Source file src/cmd/compile/internal/ssagen/ssa.go

     1  // Copyright 2015 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package ssagen
     6  
     7  import (
     8  	"bufio"
     9  	"bytes"
    10  	"cmp"
    11  	"fmt"
    12  	"go/constant"
    13  	"html"
    14  	"internal/buildcfg"
    15  	"internal/goexperiment"
    16  	"internal/runtime/gc"
    17  	"os"
    18  	"path/filepath"
    19  	"slices"
    20  	"strings"
    21  
    22  	"cmd/compile/internal/abi"
    23  	"cmd/compile/internal/base"
    24  	"cmd/compile/internal/ir"
    25  	"cmd/compile/internal/liveness"
    26  	"cmd/compile/internal/objw"
    27  	"cmd/compile/internal/reflectdata"
    28  	"cmd/compile/internal/rttype"
    29  	"cmd/compile/internal/ssa"
    30  	"cmd/compile/internal/ssa/block"
    31  	"cmd/compile/internal/ssa/ssaconfig"
    32  	"cmd/compile/internal/staticdata"
    33  	"cmd/compile/internal/typecheck"
    34  	"cmd/compile/internal/types"
    35  	"cmd/internal/obj"
    36  	"cmd/internal/objabi"
    37  	"cmd/internal/src"
    38  	"cmd/internal/sys"
    39  
    40  	rtabi "internal/abi"
    41  )
    42  
    43  var ssaConfig *ssa.Config
    44  var ssaCaches []ssa.Cache
    45  
    46  var ssaDump string     // early copy of $GOSSAFUNC; the func name to dump output for
    47  var ssaDir string      // optional destination for ssa dump file
    48  var ssaDumpStdout bool // whether to dump to stdout
    49  var ssaDumpCFG string  // generate CFGs for these phases
    50  const ssaDumpFile = "ssa.html"
    51  
    52  // ssaDumpInlined holds all inlined functions when ssaDump contains a function name.
    53  var ssaDumpInlined []*ir.Func
    54  
    55  // Maximum size we will aggregate heap allocations of scalar locals.
    56  // Almost certainly can't hurt to be as big as the tiny allocator.
    57  // Might help to be a bit bigger.
    58  const maxAggregatedHeapAllocation = 16
    59  
    60  func DumpInline(fn *ir.Func) {
    61  	if ssaDump != "" && ssaDump == ir.FuncName(fn) {
    62  		ssaDumpInlined = append(ssaDumpInlined, fn)
    63  	}
    64  }
    65  
    66  func InitEnv() {
    67  	ssaDump = os.Getenv("GOSSAFUNC")
    68  	if ssaDump == "" {
    69  		ssaDump = base.Debug.Html
    70  	}
    71  	ssaDir = os.Getenv("GOSSADIR")
    72  	if ssaDump != "" {
    73  		if strings.HasSuffix(ssaDump, "+") {
    74  			ssaDump = ssaDump[:len(ssaDump)-1]
    75  			ssaDumpStdout = true
    76  		}
    77  		spl := strings.Split(ssaDump, ":")
    78  		if len(spl) > 1 {
    79  			ssaDump = spl[0]
    80  			ssaDumpCFG = spl[1]
    81  		}
    82  	}
    83  }
    84  
    85  func InitConfig() {
    86  	types_ := ssa.NewTypes()
    87  
    88  	if Arch.SoftFloat {
    89  		softfloatInit()
    90  	}
    91  
    92  	// Generate a few pointer types that are uncommon in the frontend but common in the backend.
    93  	// Caching is disabled in the backend, so generating these here avoids allocations.
    94  	_ = types.NewPtr(types.Types[types.TINTER])                             // *interface{}
    95  	_ = types.NewPtr(types.NewPtr(types.Types[types.TSTRING]))              // **string
    96  	_ = types.NewPtr(types.NewSlice(types.Types[types.TINTER]))             // *[]interface{}
    97  	_ = types.NewPtr(types.NewPtr(types.ByteType))                          // **byte
    98  	_ = types.NewPtr(types.NewSlice(types.ByteType))                        // *[]byte
    99  	_ = types.NewPtr(types.NewSlice(types.Types[types.TSTRING]))            // *[]string
   100  	_ = types.NewPtr(types.NewPtr(types.NewPtr(types.Types[types.TUINT8]))) // ***uint8
   101  	_ = types.NewPtr(types.Types[types.TINT16])                             // *int16
   102  	_ = types.NewPtr(types.Types[types.TINT64])                             // *int64
   103  	_ = types.NewPtr(types.ErrorType)                                       // *error
   104  	_ = types.NewPtr(reflectdata.MapType())                                 // *internal/runtime/maps.Map
   105  	_ = types.NewPtr(deferstruct())                                         // *runtime._defer
   106  	types.NewPtrCacheEnabled = false
   107  	ssaConfig = ssa.NewConfig(base.Ctxt.Arch.Name, *types_, base.Ctxt, base.Flag.N == 0, Arch.SoftFloat)
   108  	ssaConfig.Race = base.Flag.Race
   109  	ssaCaches = make([]ssa.Cache, base.Flag.LowerC)
   110  
   111  	// Set up some runtime functions we'll need to call.
   112  	ir.Syms.AssertE2I = typecheck.LookupRuntimeFunc("assertE2I")
   113  	ir.Syms.AssertE2I2 = typecheck.LookupRuntimeFunc("assertE2I2")
   114  	ir.Syms.CgoCheckMemmove = typecheck.LookupRuntimeFunc("cgoCheckMemmove")
   115  	ir.Syms.CgoCheckPtrWrite = typecheck.LookupRuntimeFunc("cgoCheckPtrWrite")
   116  	ir.Syms.CheckPtrAlignment = typecheck.LookupRuntimeFunc("checkptrAlignment")
   117  	ir.Syms.Deferproc = typecheck.LookupRuntimeFunc("deferproc")
   118  	ir.Syms.Deferprocat = typecheck.LookupRuntimeFunc("deferprocat")
   119  	ir.Syms.DeferprocStack = typecheck.LookupRuntimeFunc("deferprocStack")
   120  	ir.Syms.Deferreturn = typecheck.LookupRuntimeFunc("deferreturn")
   121  	ir.Syms.Duffcopy = typecheck.LookupRuntimeFunc("duffcopy")
   122  	ir.Syms.Duffzero = typecheck.LookupRuntimeFunc("duffzero")
   123  	ir.Syms.GCWriteBarrier[0] = typecheck.LookupRuntimeFunc("gcWriteBarrier1")
   124  	ir.Syms.GCWriteBarrier[1] = typecheck.LookupRuntimeFunc("gcWriteBarrier2")
   125  	ir.Syms.GCWriteBarrier[2] = typecheck.LookupRuntimeFunc("gcWriteBarrier3")
   126  	ir.Syms.GCWriteBarrier[3] = typecheck.LookupRuntimeFunc("gcWriteBarrier4")
   127  	ir.Syms.GCWriteBarrier[4] = typecheck.LookupRuntimeFunc("gcWriteBarrier5")
   128  	ir.Syms.GCWriteBarrier[5] = typecheck.LookupRuntimeFunc("gcWriteBarrier6")
   129  	ir.Syms.GCWriteBarrier[6] = typecheck.LookupRuntimeFunc("gcWriteBarrier7")
   130  	ir.Syms.GCWriteBarrier[7] = typecheck.LookupRuntimeFunc("gcWriteBarrier8")
   131  	ir.Syms.Goschedguarded = typecheck.LookupRuntimeFunc("goschedguarded")
   132  	ir.Syms.Growslice = typecheck.LookupRuntimeFunc("growslice")
   133  	ir.Syms.GrowsliceBuf = typecheck.LookupRuntimeFunc("growsliceBuf")
   134  	ir.Syms.GrowsliceBufNoAlias = typecheck.LookupRuntimeFunc("growsliceBufNoAlias")
   135  	ir.Syms.GrowsliceNoAlias = typecheck.LookupRuntimeFunc("growsliceNoAlias")
   136  	ir.Syms.MoveSlice = typecheck.LookupRuntimeFunc("moveSlice")
   137  	ir.Syms.MoveSliceNoScan = typecheck.LookupRuntimeFunc("moveSliceNoScan")
   138  	ir.Syms.MoveSliceNoCap = typecheck.LookupRuntimeFunc("moveSliceNoCap")
   139  	ir.Syms.MoveSliceNoCapNoScan = typecheck.LookupRuntimeFunc("moveSliceNoCapNoScan")
   140  	ir.Syms.InterfaceSwitch = typecheck.LookupRuntimeFunc("interfaceSwitch")
   141  	for i := 1; i < len(ir.Syms.MallocGCSmallNoScan); i++ {
   142  		ir.Syms.MallocGCSmallNoScan[i] = typecheck.LookupRuntimeFunc(fmt.Sprintf("mallocgcSmallNoScanSC%d", i))
   143  	}
   144  	for i := 1; i < len(ir.Syms.MallocGCSmallScanNoHeader); i++ {
   145  		ir.Syms.MallocGCSmallScanNoHeader[i] = typecheck.LookupRuntimeFunc(fmt.Sprintf("mallocgcSmallScanNoHeaderSC%d", i))
   146  	}
   147  	ir.Syms.MallocGCTiny = typecheck.LookupRuntimeFunc("mallocgcTinySC2")
   148  	ir.Syms.MallocGC = typecheck.LookupRuntimeFunc("mallocgc")
   149  	ir.Syms.Memmove = typecheck.LookupRuntimeFunc("memmove")
   150  	ir.Syms.Memequal = typecheck.LookupRuntimeFunc("memequal")
   151  	ir.Syms.Msanread = typecheck.LookupRuntimeFunc("msanread")
   152  	ir.Syms.Msanwrite = typecheck.LookupRuntimeFunc("msanwrite")
   153  	ir.Syms.Msanmove = typecheck.LookupRuntimeFunc("msanmove")
   154  	ir.Syms.Asanread = typecheck.LookupRuntimeFunc("asanread")
   155  	ir.Syms.Asanwrite = typecheck.LookupRuntimeFunc("asanwrite")
   156  	ir.Syms.Newobject = typecheck.LookupRuntimeFunc("newobject")
   157  	ir.Syms.Newproc = typecheck.LookupRuntimeFunc("newproc")
   158  	ir.Syms.PanicBounds = typecheck.LookupRuntimeFunc("panicBounds")
   159  	ir.Syms.PanicExtend = typecheck.LookupRuntimeFunc("panicExtend")
   160  	ir.Syms.Panicdivide = typecheck.LookupRuntimeFunc("panicdivide")
   161  	ir.Syms.PanicdottypeE = typecheck.LookupRuntimeFunc("panicdottypeE")
   162  	ir.Syms.PanicdottypeI = typecheck.LookupRuntimeFunc("panicdottypeI")
   163  	ir.Syms.Panicnildottype = typecheck.LookupRuntimeFunc("panicnildottype")
   164  	ir.Syms.Panicoverflow = typecheck.LookupRuntimeFunc("panicoverflow")
   165  	ir.Syms.Panicshift = typecheck.LookupRuntimeFunc("panicshift")
   166  	ir.Syms.PanicSimdImm = typecheck.LookupRuntimeFunc("panicSimdImm")
   167  	ir.Syms.Racefuncenter = typecheck.LookupRuntimeFunc("racefuncenter")
   168  	ir.Syms.Racefuncexit = typecheck.LookupRuntimeFunc("racefuncexit")
   169  	ir.Syms.Raceread = typecheck.LookupRuntimeFunc("raceread")
   170  	ir.Syms.Racereadrange = typecheck.LookupRuntimeFunc("racereadrange")
   171  	ir.Syms.Racewrite = typecheck.LookupRuntimeFunc("racewrite")
   172  	ir.Syms.Racewriterange = typecheck.LookupRuntimeFunc("racewriterange")
   173  	ir.Syms.TypeAssert = typecheck.LookupRuntimeFunc("typeAssert")
   174  	ir.Syms.WBZero = typecheck.LookupRuntimeFunc("wbZero")
   175  	ir.Syms.WBMove = typecheck.LookupRuntimeFunc("wbMove")
   176  	ir.Syms.X86HasAVX = typecheck.LookupRuntimeVar("x86HasAVX")                       // bool
   177  	ir.Syms.X86HasFMA = typecheck.LookupRuntimeVar("x86HasFMA")                       // bool
   178  	ir.Syms.X86HasPOPCNT = typecheck.LookupRuntimeVar("x86HasPOPCNT")                 // bool
   179  	ir.Syms.X86HasSSE41 = typecheck.LookupRuntimeVar("x86HasSSE41")                   // bool
   180  	ir.Syms.ARMHasVFPv4 = typecheck.LookupRuntimeVar("armHasVFPv4")                   // bool
   181  	ir.Syms.ARM64HasATOMICS = typecheck.LookupRuntimeVar("arm64HasATOMICS")           // bool
   182  	ir.Syms.Loong64HasLAMCAS = typecheck.LookupRuntimeVar("loong64HasLAMCAS")         // bool
   183  	ir.Syms.Loong64HasLAM_BH = typecheck.LookupRuntimeVar("loong64HasLAM_BH")         // bool
   184  	ir.Syms.Loong64HasDBAR_HINTS = typecheck.LookupRuntimeVar("loong64HasDBAR_HINTS") // bool
   185  	ir.Syms.Loong64HasLSX = typecheck.LookupRuntimeVar("loong64HasLSX")               // bool
   186  	ir.Syms.RISCV64HasZbb = typecheck.LookupRuntimeVar("riscv64HasZbb")               // bool
   187  	ir.Syms.Staticuint64s = typecheck.LookupRuntimeVar("staticuint64s")
   188  	ir.Syms.Typedmemmove = typecheck.LookupRuntimeFunc("typedmemmove")
   189  	ir.Syms.Udiv = typecheck.LookupRuntimeVar("udiv")                 // asm func with special ABI
   190  	ir.Syms.WriteBarrier = typecheck.LookupRuntimeVar("writeBarrier") // struct { bool; ... }
   191  	ir.Syms.Zerobase = typecheck.LookupRuntimeVar("zerobase")
   192  	ir.Syms.ZeroVal = typecheck.LookupRuntimeVar("zeroVal")
   193  
   194  	if Arch.LinkArch.Family == sys.Wasm {
   195  		BoundsCheckFunc[ssa.BoundsIndex] = typecheck.LookupRuntimeFunc("goPanicIndex")
   196  		BoundsCheckFunc[ssa.BoundsIndexU] = typecheck.LookupRuntimeFunc("goPanicIndexU")
   197  		BoundsCheckFunc[ssa.BoundsSliceAlen] = typecheck.LookupRuntimeFunc("goPanicSliceAlen")
   198  		BoundsCheckFunc[ssa.BoundsSliceAlenU] = typecheck.LookupRuntimeFunc("goPanicSliceAlenU")
   199  		BoundsCheckFunc[ssa.BoundsSliceAcap] = typecheck.LookupRuntimeFunc("goPanicSliceAcap")
   200  		BoundsCheckFunc[ssa.BoundsSliceAcapU] = typecheck.LookupRuntimeFunc("goPanicSliceAcapU")
   201  		BoundsCheckFunc[ssa.BoundsSliceB] = typecheck.LookupRuntimeFunc("goPanicSliceB")
   202  		BoundsCheckFunc[ssa.BoundsSliceBU] = typecheck.LookupRuntimeFunc("goPanicSliceBU")
   203  		BoundsCheckFunc[ssa.BoundsSlice3Alen] = typecheck.LookupRuntimeFunc("goPanicSlice3Alen")
   204  		BoundsCheckFunc[ssa.BoundsSlice3AlenU] = typecheck.LookupRuntimeFunc("goPanicSlice3AlenU")
   205  		BoundsCheckFunc[ssa.BoundsSlice3Acap] = typecheck.LookupRuntimeFunc("goPanicSlice3Acap")
   206  		BoundsCheckFunc[ssa.BoundsSlice3AcapU] = typecheck.LookupRuntimeFunc("goPanicSlice3AcapU")
   207  		BoundsCheckFunc[ssa.BoundsSlice3B] = typecheck.LookupRuntimeFunc("goPanicSlice3B")
   208  		BoundsCheckFunc[ssa.BoundsSlice3BU] = typecheck.LookupRuntimeFunc("goPanicSlice3BU")
   209  		BoundsCheckFunc[ssa.BoundsSlice3C] = typecheck.LookupRuntimeFunc("goPanicSlice3C")
   210  		BoundsCheckFunc[ssa.BoundsSlice3CU] = typecheck.LookupRuntimeFunc("goPanicSlice3CU")
   211  		BoundsCheckFunc[ssa.BoundsConvert] = typecheck.LookupRuntimeFunc("goPanicSliceConvert")
   212  	}
   213  
   214  	// Wasm (all asm funcs with special ABIs)
   215  	ir.Syms.WasmDiv = typecheck.LookupRuntimeVar("wasmDiv")
   216  	ir.Syms.WasmTruncS = typecheck.LookupRuntimeVar("wasmTruncS")
   217  	ir.Syms.WasmTruncU = typecheck.LookupRuntimeVar("wasmTruncU")
   218  	ir.Syms.SigPanic = typecheck.LookupRuntimeFunc("sigpanic")
   219  }
   220  
   221  func InitTables() {
   222  	initIntrinsics(nil)
   223  }
   224  
   225  // AbiForBodylessFuncStackMap returns the ABI for a bodyless function's stack map.
   226  // This is not necessarily the ABI used to call it.
   227  // Currently (1.17 dev) such a stack map is always ABI0;
   228  // any ABI wrapper that is present is nosplit, hence a precise
   229  // stack map is not needed there (the parameters survive only long
   230  // enough to call the wrapped assembly function).
   231  func AbiForBodylessFuncStackMap(fn *ir.Func) *abi.ABIConfig {
   232  	return ssaConfig.ABI0
   233  }
   234  
   235  // abiForFunc implements ABI policy for a function.
   236  // Passing a nil function returns the default ABI based on experiment configuration.
   237  func abiForFunc(fn *ir.Func, abi0, abi1 *abi.ABIConfig) *abi.ABIConfig {
   238  	if buildcfg.Experiment.RegabiArgs {
   239  		// Select the ABI based on the function's defining ABI.
   240  		if fn == nil {
   241  			return abi1
   242  		}
   243  		switch fn.ABI {
   244  		case obj.ABI0:
   245  			return abi0
   246  		case obj.ABIInternal:
   247  			// TODO(austin): Clean up the nomenclature here.
   248  			// It's not clear that "abi1" is ABIInternal.
   249  			return abi1
   250  		}
   251  		base.Fatalf("function %v has unknown ABI %v", fn, fn.ABI)
   252  		panic("not reachable")
   253  	}
   254  
   255  	a := abi0
   256  	if fn != nil {
   257  		if fn.Pragma&ir.RegisterParams != 0 { // TODO(register args) remove after register abi is working
   258  			a = abi1
   259  		}
   260  	}
   261  	return a
   262  }
   263  
   264  // emitOpenDeferInfo emits FUNCDATA information about the defers in a function
   265  // that is using open-coded defers.  This funcdata is used to determine the active
   266  // defers in a function and execute those defers during panic processing.
   267  //
   268  // The funcdata is all encoded in varints (since values will almost always be less than
   269  // 128, but stack offsets could potentially be up to 2Gbyte). All "locations" (offsets)
   270  // for stack variables are specified as the number of bytes below varp (pointer to the
   271  // top of the local variables) for their starting address. The format is:
   272  //
   273  //   - Offset of the deferBits variable
   274  //   - Offset of the first closure slot (the rest are laid out consecutively).
   275  func (s *state) emitOpenDeferInfo() {
   276  	firstOffset := s.openDefers[0].closureNode.FrameOffset()
   277  
   278  	// Verify that cmpstackvarlt laid out the slots in order.
   279  	for i, r := range s.openDefers {
   280  		have := r.closureNode.FrameOffset()
   281  		want := firstOffset + int64(i)*int64(types.PtrSize)
   282  		if have != want {
   283  			base.FatalfAt(s.curfn.Pos(), "unexpected frame offset for open-coded defer slot #%v: have %v, want %v", i, have, want)
   284  		}
   285  	}
   286  
   287  	x := base.Ctxt.Lookup(s.curfn.LSym.Name + ".opendefer")
   288  	x.Set(obj.AttrContentAddressable, true)
   289  	x.Align = 1
   290  	s.curfn.LSym.Func().OpenCodedDeferInfo = x
   291  
   292  	off := 0
   293  	off = objw.Uvarint(x, off, uint64(-s.deferBitsTemp.FrameOffset()))
   294  	off = objw.Uvarint(x, off, uint64(-firstOffset))
   295  }
   296  
   297  // buildssa builds an SSA function for fn.
   298  // worker indicates which of the backend workers is doing the processing.
   299  func buildssa(fn *ir.Func, worker int, isPgoHot bool) (*ssa.Func, *ssa.HTMLWriter) {
   300  	name := ir.FuncName(fn)
   301  
   302  	abiSelf := abiForFunc(fn, ssaConfig.ABI0, ssaConfig.ABI1)
   303  
   304  	printssa := false
   305  	// match either a simple name e.g. "(*Reader).Reset", package.name e.g. "compress/gzip.(*Reader).Reset", or subpackage name "gzip.(*Reader).Reset"
   306  	// optionally allows an ABI suffix specification in the GOSSAHASH, e.g. "(*Reader).Reset<0>" etc
   307  	if strings.Contains(ssaDump, name) { // in all the cases the function name is entirely contained within the GOSSAFUNC string.
   308  		nameOptABI := name
   309  		if l := len(ssaDump); l > 1 && ssaDump[l-2] == ',' { // ABI specification
   310  			nameOptABI = ssa.FuncNameABI(name, abiSelf.Which())
   311  		} else if strings.HasSuffix(ssaDump, ">") { // if they use the linker syntax instead....
   312  			l := len(ssaDump)
   313  			if l >= 3 && ssaDump[l-3] == '<' {
   314  				nameOptABI = ssa.FuncNameABI(name, abiSelf.Which())
   315  				ssaDump = ssaDump[:l-3] + "," + ssaDump[l-2:l-1]
   316  			}
   317  		}
   318  		pkgDotName := base.Ctxt.Pkgpath + "." + nameOptABI
   319  		printssa = nameOptABI == ssaDump || // "(*Reader).Reset"
   320  			pkgDotName == ssaDump || // "compress/gzip.(*Reader).Reset"
   321  			strings.HasSuffix(pkgDotName, ssaDump) && strings.HasSuffix(pkgDotName, "/"+ssaDump) // "gzip.(*Reader).Reset"
   322  	}
   323  
   324  	var astBuf *bytes.Buffer
   325  	if printssa {
   326  		astBuf = &bytes.Buffer{}
   327  		ir.FDumpList(astBuf, "buildssa-body", fn.Body)
   328  		if ssaDumpStdout {
   329  			fmt.Println("generating SSA for", name)
   330  			fmt.Print(astBuf.String())
   331  		}
   332  	}
   333  
   334  	var s state
   335  	s.pushLine(fn.Pos())
   336  	defer s.popLine()
   337  
   338  	s.hasdefer = fn.HasDefer()
   339  	if fn.Pragma&ir.CgoUnsafeArgs != 0 {
   340  		s.cgoUnsafeArgs = true
   341  	}
   342  	s.checkPtrEnabled = ir.ShouldCheckPtr(fn, 1)
   343  
   344  	if base.Flag.Cfg.Instrumenting && fn.Pragma&ir.Norace == 0 && !fn.Linksym().ABIWrapper() {
   345  		if !base.Flag.Race || !objabi.LookupPkgSpecial(fn.Sym().Pkg.Path).NoRaceFunc {
   346  			s.instrumentMemory = true
   347  			if base.Flag.Race {
   348  				s.instrumentEnterExit = true
   349  			}
   350  		}
   351  	}
   352  
   353  	fe := ssafn{
   354  		curfn: fn,
   355  		log:   printssa && ssaDumpStdout,
   356  	}
   357  	s.curfn = fn
   358  
   359  	cache := &ssaCaches[worker]
   360  	cache.Reset()
   361  
   362  	s.f = ssaConfig.NewFunc(&fe, cache)
   363  	s.config = ssaConfig
   364  	s.f.Type = fn.Type()
   365  	s.f.Name = name
   366  	s.f.PrintOrHtmlSSA = printssa
   367  	if fn.Pragma&ir.Nosplit != 0 {
   368  		s.f.NoSplit = true
   369  	}
   370  	s.f.ABI0 = ssaConfig.ABI0
   371  	s.f.ABI1 = ssaConfig.ABI1
   372  	s.f.ABIDefault = abiForFunc(nil, ssaConfig.ABI0, ssaConfig.ABI1)
   373  	s.f.ABISelf = abiSelf
   374  
   375  	s.panics = map[funcLine]*ssa.Block{}
   376  	s.softFloat = s.config.SoftFloat
   377  
   378  	// Allocate starting block
   379  	s.f.Entry = s.f.NewBlock(block.BlockPlain)
   380  	s.f.Entry.Pos = fn.Pos()
   381  	s.f.IsPgoHot = isPgoHot
   382  	var htmlWriter *ssa.HTMLWriter
   383  
   384  	if printssa {
   385  		ssaDF := ssaDumpFile
   386  		if ssaDir != "" {
   387  			ssaDF = filepath.Join(ssaDir, base.Ctxt.Pkgpath+"."+s.f.NameABI()+".html")
   388  			ssaD := filepath.Dir(ssaDF)
   389  			os.MkdirAll(ssaD, 0755)
   390  		}
   391  		htmlWriter = ssa.NewHTMLWriter(ssaDF, s.f, ssaDumpCFG)
   392  		// TODO: generate and print a mapping from nodes to values and blocks
   393  		dumpSourcesColumn(htmlWriter, fn)
   394  		htmlWriter.WriteAST("AST", astBuf)
   395  		s.f.FatalCleanup = htmlWriter.FatalCleanup
   396  	}
   397  
   398  	// Allocate starting values
   399  	s.labels = map[string]*ssaLabel{}
   400  	s.fwdVars = map[ir.Node]*ssa.Value{}
   401  	s.startmem = s.entryNewValue0(ssa.OpInitMem, types.TypeMem)
   402  
   403  	s.hasOpenDefers = base.Flag.N == 0 && s.hasdefer && !s.curfn.OpenCodedDeferDisallowed()
   404  	switch {
   405  	case base.Debug.NoOpenDefer != 0:
   406  		s.hasOpenDefers = false
   407  	case s.hasOpenDefers && (base.Ctxt.Flag_shared || base.Ctxt.Flag_dynlink) && base.Ctxt.Arch.Name == "386":
   408  		// Don't support open-coded defers for 386 ONLY when using shared
   409  		// libraries, because there is extra code (added by rewriteToUseGot())
   410  		// preceding the deferreturn/ret code that we don't track correctly.
   411  		//
   412  		// TODO this restriction can be removed given adjusted offset in computeDeferReturn in cmd/link/internal/ld/pcln.go
   413  		s.hasOpenDefers = false
   414  	}
   415  	if s.hasOpenDefers && s.instrumentEnterExit {
   416  		// Skip doing open defers if we need to instrument function
   417  		// returns for the race detector, since we will not generate that
   418  		// code in the case of the extra deferreturn/ret segment.
   419  		s.hasOpenDefers = false
   420  	}
   421  	if s.hasOpenDefers {
   422  		// Similarly, skip if there are any heap-allocated result
   423  		// parameters that need to be copied back to their stack slots.
   424  		for _, f := range s.curfn.Type().Results() {
   425  			if !f.Nname.(*ir.Name).OnStack() {
   426  				s.hasOpenDefers = false
   427  				break
   428  			}
   429  		}
   430  	}
   431  	if s.hasOpenDefers &&
   432  		s.curfn.NumReturns*s.curfn.NumDefers > 15 {
   433  		// Since we are generating defer calls at every exit for
   434  		// open-coded defers, skip doing open-coded defers if there are
   435  		// too many returns (especially if there are multiple defers).
   436  		// Open-coded defers are most important for improving performance
   437  		// for smaller functions (which don't have many returns).
   438  		s.hasOpenDefers = false
   439  	}
   440  
   441  	s.sp = s.entryNewValue0(ssa.OpSP, types.Types[types.TUINTPTR]) // TODO: use generic pointer type (unsafe.Pointer?) instead
   442  	s.sb = s.entryNewValue0(ssa.OpSB, types.Types[types.TUINTPTR])
   443  
   444  	s.startBlock(s.f.Entry)
   445  	s.vars[memVar] = s.startmem
   446  	if s.hasOpenDefers {
   447  		// Create the deferBits variable and stack slot.  deferBits is a
   448  		// bitmask showing which of the open-coded defers in this function
   449  		// have been activated.
   450  		deferBitsTemp := typecheck.TempAt(src.NoXPos, s.curfn, types.Types[types.TUINT8])
   451  		deferBitsTemp.SetAddrtaken(true)
   452  		s.deferBitsTemp = deferBitsTemp
   453  		// For this value, AuxInt is initialized to zero by default
   454  		startDeferBits := s.entryNewValue0(ssa.OpConst8, types.Types[types.TUINT8])
   455  		s.vars[deferBitsVar] = startDeferBits
   456  		s.deferBitsAddr = s.addr(deferBitsTemp)
   457  		s.store(types.Types[types.TUINT8], s.deferBitsAddr, startDeferBits)
   458  		// Make sure that the deferBits stack slot is kept alive (for use
   459  		// by panics) and stores to deferBits are not eliminated, even if
   460  		// all checking code on deferBits in the function exit can be
   461  		// eliminated, because the defer statements were all
   462  		// unconditional.
   463  		s.vars[memVar] = s.newValue1Apos(ssa.OpVarLive, types.TypeMem, deferBitsTemp, s.mem(), false)
   464  	}
   465  
   466  	var params *abi.ABIParamResultInfo
   467  	params = s.f.ABISelf.ABIAnalyze(fn.Type(), true)
   468  
   469  	// The backend's stackframe pass prunes away entries from the fn's
   470  	// Dcl list, including PARAMOUT nodes that correspond to output
   471  	// params passed in registers. Walk the Dcl list and capture these
   472  	// nodes to a side list, so that we'll have them available during
   473  	// DWARF-gen later on. See issue 48573 for more details.
   474  	var debugInfo ssa.FuncDebug
   475  	for _, n := range fn.Dcl {
   476  		if n.Class == ir.PPARAMOUT && n.IsOutputParamInRegisters() {
   477  			debugInfo.RegOutputParams = append(debugInfo.RegOutputParams, n)
   478  		}
   479  	}
   480  	fn.DebugInfo = &debugInfo
   481  
   482  	// Generate addresses of local declarations
   483  	s.decladdrs = map[*ir.Name]*ssa.Value{}
   484  	for _, n := range fn.Dcl {
   485  		switch n.Class {
   486  		case ir.PPARAM:
   487  			// Be aware that blank and unnamed input parameters will not appear here, but do appear in the type
   488  			s.decladdrs[n] = s.entryNewValue2A(ssa.OpLocalAddr, types.NewPtr(n.Type()), n, s.sp, s.startmem)
   489  		case ir.PPARAMOUT:
   490  			s.decladdrs[n] = s.entryNewValue2A(ssa.OpLocalAddr, types.NewPtr(n.Type()), n, s.sp, s.startmem)
   491  		case ir.PAUTO:
   492  			// processed at each use, to prevent Addr coming
   493  			// before the decl.
   494  		default:
   495  			s.Fatalf("local variable with class %v unimplemented", n.Class)
   496  		}
   497  	}
   498  
   499  	s.f.OwnAux = ssa.OwnAuxCall(fn.LSym, params)
   500  
   501  	// Populate SSAable arguments.
   502  	for _, n := range fn.Dcl {
   503  		if n.Class == ir.PPARAM {
   504  			if s.canSSA(n) {
   505  				v := s.newValue0A(ssa.OpArg, n.Type(), n)
   506  				s.vars[n] = v
   507  				s.addNamedValue(n, v) // This helps with debugging information, not needed for compilation itself.
   508  			} else { // address was taken AND/OR too large for SSA
   509  				paramAssignment := ssa.ParamAssignmentForArgName(s.f, n)
   510  				if len(paramAssignment.Registers) > 0 {
   511  					if ssa.CanSSA(n.Type()) { // SSA-able type, so address was taken -- receive value in OpArg, DO NOT bind to var, store immediately to memory.
   512  						v := s.newValue0A(ssa.OpArg, n.Type(), n)
   513  						s.store(n.Type(), s.decladdrs[n], v)
   514  					} else { // Too big for SSA.
   515  						// Brute force, and early, do a bunch of stores from registers
   516  						// Note that expand calls knows about this and doesn't trouble itself with larger-than-SSA-able Args in registers.
   517  						s.storeParameterRegsToStack(s.f.ABISelf, paramAssignment, n, s.decladdrs[n], false)
   518  					}
   519  				}
   520  			}
   521  		}
   522  	}
   523  
   524  	// Populate closure variables.
   525  	if fn.Needctxt() {
   526  		clo := s.entryNewValue0(ssa.OpGetClosurePtr, s.f.Config.Types.BytePtr)
   527  		if fn.RangeParent != nil && base.Flag.N != 0 {
   528  			// For a range body closure, keep its closure pointer live on the
   529  			// stack with a special name, so the debugger can look for it and
   530  			// find the parent frame.
   531  			sym := &types.Sym{Name: ".closureptr", Pkg: types.LocalPkg}
   532  			cloSlot := s.curfn.NewLocal(src.NoXPos, sym, s.f.Config.Types.BytePtr)
   533  			cloSlot.SetUsed(true)
   534  			cloSlot.SetEsc(ir.EscNever)
   535  			cloSlot.SetAddrtaken(true)
   536  			s.f.CloSlot = cloSlot
   537  			s.vars[memVar] = s.newValue1Apos(ssa.OpVarDef, types.TypeMem, cloSlot, s.mem(), false)
   538  			addr := s.addr(cloSlot)
   539  			s.store(s.f.Config.Types.BytePtr, addr, clo)
   540  			// Keep it from being dead-store eliminated.
   541  			s.vars[memVar] = s.newValue1Apos(ssa.OpVarLive, types.TypeMem, cloSlot, s.mem(), false)
   542  		}
   543  		csiter := typecheck.NewClosureStructIter(fn.ClosureVars)
   544  		for {
   545  			n, typ, offset := csiter.Next()
   546  			if n == nil {
   547  				break
   548  			}
   549  
   550  			ptr := s.newValue1I(ssa.OpOffPtr, types.NewPtr(typ), offset, clo)
   551  
   552  			// If n is a small variable captured by value, promote
   553  			// it to PAUTO so it can be converted to SSA.
   554  			//
   555  			// Note: While we never capture a variable by value if
   556  			// the user took its address, we may have generated
   557  			// runtime calls that did (#43701). Since we don't
   558  			// convert Addrtaken variables to SSA anyway, no point
   559  			// in promoting them either.
   560  			if n.Byval() && !n.Addrtaken() && ssa.CanSSA(n.Type()) {
   561  				n.Class = ir.PAUTO
   562  				fn.Dcl = append(fn.Dcl, n)
   563  				s.assign(n, s.load(n.Type(), ptr), false, 0)
   564  				continue
   565  			}
   566  
   567  			if !n.Byval() {
   568  				ptr = s.load(typ, ptr)
   569  			}
   570  			s.setHeapaddr(fn.Pos(), n, ptr)
   571  		}
   572  	}
   573  
   574  	// Convert the AST-based IR to the SSA-based IR
   575  	if s.instrumentEnterExit {
   576  		s.rtcall(ir.Syms.Racefuncenter, true, nil, s.newValue0(ssa.OpGetCallerPC, types.Types[types.TUINTPTR]))
   577  	}
   578  	s.zeroResults()
   579  	s.paramsToHeap()
   580  	s.stmtList(fn.Body)
   581  
   582  	// fallthrough to exit
   583  	if s.curBlock != nil {
   584  		s.pushLine(fn.Endlineno)
   585  		s.exit()
   586  		s.popLine()
   587  	}
   588  
   589  	for _, b := range s.f.Blocks {
   590  		if b.Pos != src.NoXPos {
   591  			s.updateUnsetPredPos(b)
   592  		}
   593  	}
   594  
   595  	htmlWriter.WritePhase("before insert phis", "before insert phis")
   596  
   597  	s.insertPhis()
   598  
   599  	// Main call to ssa package to compile function
   600  	ssa.Compile(s.f, htmlWriter)
   601  
   602  	fe.AllocFrame(s.f)
   603  
   604  	if len(s.openDefers) != 0 {
   605  		s.emitOpenDeferInfo()
   606  	}
   607  
   608  	// Record incoming parameter spill information for morestack calls emitted in the assembler.
   609  	// This is done here, using all the parameters (used, partially used, and unused) because
   610  	// it mimics the behavior of the former ABI (everything stored) and because it's not 100%
   611  	// clear if naming conventions are respected in autogenerated code.
   612  	// TODO figure out exactly what's unused, don't spill it. Make liveness fine-grained, also.
   613  	for _, p := range params.InParams() {
   614  		typs, offs := p.RegisterTypesAndOffsets()
   615  		if len(offs) < len(typs) {
   616  			s.Fatalf("len(offs)=%d < len(typs)=%d, params=\n%s", len(offs), len(typs), params)
   617  		}
   618  		for i, t := range typs {
   619  			o := offs[i]                // offset within parameter
   620  			fo := p.FrameOffset(params) // offset of parameter in frame
   621  			reg := ssa.ObjRegForAbiReg(p.Registers[i], s.f.Config)
   622  			s.f.RegArgs = append(s.f.RegArgs, ssa.Spill{Reg: reg, Offset: fo + o, Type: t})
   623  		}
   624  	}
   625  
   626  	return s.f, htmlWriter
   627  }
   628  
   629  func (s *state) storeParameterRegsToStack(abi *abi.ABIConfig, paramAssignment *abi.ABIParamAssignment, n *ir.Name, addr *ssa.Value, pointersOnly bool) {
   630  	typs, offs := paramAssignment.RegisterTypesAndOffsets()
   631  	for i, t := range typs {
   632  		if pointersOnly && !t.IsPtrShaped() {
   633  			continue
   634  		}
   635  		r := paramAssignment.Registers[i]
   636  		o := offs[i]
   637  		op, reg := ssa.ArgOpAndRegisterFor(r, abi)
   638  		aux := &ssa.AuxNameOffset{Name: n, Offset: o}
   639  		v := s.newValue0I(op, t, reg)
   640  		v.Aux = aux
   641  		p := s.newValue1I(ssa.OpOffPtr, types.NewPtr(t), o, addr)
   642  		s.store(t, p, v)
   643  	}
   644  }
   645  
   646  // zeroResults zeros the return values at the start of the function.
   647  // We need to do this very early in the function.  Defer might stop a
   648  // panic and show the return values as they exist at the time of
   649  // panic.  For precise stacks, the garbage collector assumes results
   650  // are always live, so we need to zero them before any allocations,
   651  // even allocations to move params/results to the heap.
   652  func (s *state) zeroResults() {
   653  	for _, f := range s.curfn.Type().Results() {
   654  		n := f.Nname.(*ir.Name)
   655  		if !n.OnStack() {
   656  			// The local which points to the return value is the
   657  			// thing that needs zeroing. This is already handled
   658  			// by a Needzero annotation in plive.go:(*liveness).epilogue.
   659  			continue
   660  		}
   661  		// Zero the stack location containing f.
   662  		if typ := n.Type(); ssa.CanSSA(typ) {
   663  			s.assign(n, s.zeroVal(typ), false, 0)
   664  		} else {
   665  			if typ.HasPointers() || ssa.IsMergeCandidate(n) {
   666  				s.vars[memVar] = s.newValue1A(ssa.OpVarDef, types.TypeMem, n, s.mem())
   667  			}
   668  			s.zero(n.Type(), s.decladdrs[n])
   669  		}
   670  	}
   671  }
   672  
   673  // paramsToHeap produces code to allocate memory for heap-escaped parameters
   674  // and to copy non-result parameters' values from the stack.
   675  func (s *state) paramsToHeap() {
   676  	do := func(params []*types.Field) {
   677  		for _, f := range params {
   678  			if f.Nname == nil {
   679  				continue // anonymous or blank parameter
   680  			}
   681  			n := f.Nname.(*ir.Name)
   682  			if ir.IsBlank(n) || n.OnStack() {
   683  				continue
   684  			}
   685  			s.newHeapaddr(n)
   686  			if n.Class == ir.PPARAM {
   687  				s.move(n.Type(), s.expr(n.Heapaddr), s.decladdrs[n])
   688  			}
   689  		}
   690  	}
   691  
   692  	typ := s.curfn.Type()
   693  	do(typ.Recvs())
   694  	do(typ.Params())
   695  	do(typ.Results())
   696  }
   697  
   698  // allocSizeAndAlign returns the size and alignment of t.
   699  // Normally just t.Size() and t.Alignment(), but there
   700  // is a special case to handle 64-bit atomics on 32-bit systems.
   701  func allocSizeAndAlign(t *types.Type) (int64, int64) {
   702  	size, align := t.Size(), t.Alignment()
   703  	if types.PtrSize == 4 && align == 4 && size >= 8 {
   704  		// For 64-bit atomics on 32-bit systems.
   705  		size = types.RoundUp(size, 8)
   706  		align = 8
   707  	}
   708  	return size, align
   709  }
   710  func allocSize(t *types.Type) int64 {
   711  	size, _ := allocSizeAndAlign(t)
   712  	return size
   713  }
   714  func allocAlign(t *types.Type) int64 {
   715  	_, align := allocSizeAndAlign(t)
   716  	return align
   717  }
   718  
   719  // newHeapaddr allocates heap memory for n and sets its heap address.
   720  func (s *state) newHeapaddr(n *ir.Name) {
   721  	size := allocSize(n.Type())
   722  	if n.Type().HasPointers() || size >= maxAggregatedHeapAllocation || size == 0 {
   723  		s.setHeapaddr(n.Pos(), n, s.newObject(n.Type()))
   724  		return
   725  	}
   726  
   727  	// Do we have room together with our pending allocations?
   728  	// If not, flush all the current ones.
   729  	var used int64
   730  	for _, v := range s.pendingHeapAllocations {
   731  		used += allocSize(v.Type.Elem())
   732  	}
   733  	if used+size > maxAggregatedHeapAllocation {
   734  		s.flushPendingHeapAllocations()
   735  	}
   736  
   737  	var allocCall *ssa.Value // (SelectN [0] (call of runtime.newobject))
   738  	if len(s.pendingHeapAllocations) == 0 {
   739  		// Make an allocation, but the type being allocated is just
   740  		// the first pending object. We will come back and update it
   741  		// later if needed.
   742  		allocCall = s.newObjectNonSpecialized(n.Type(), nil)
   743  	} else {
   744  		allocCall = s.pendingHeapAllocations[0].Args[0]
   745  	}
   746  	// v is an offset to the shared allocation. Offsets are dummy 0s for now.
   747  	v := s.newValue1I(ssa.OpOffPtr, n.Type().PtrTo(), 0, allocCall)
   748  
   749  	// Add to list of pending allocations.
   750  	s.pendingHeapAllocations = append(s.pendingHeapAllocations, v)
   751  
   752  	// Finally, record for posterity.
   753  	s.setHeapaddr(n.Pos(), n, v)
   754  }
   755  
   756  func (s *state) flushPendingHeapAllocations() {
   757  	pending := s.pendingHeapAllocations
   758  	if len(pending) == 0 {
   759  		return // nothing to do
   760  	}
   761  	s.pendingHeapAllocations = nil // reset state
   762  	ptr := pending[0].Args[0]      // The SelectN [0] op
   763  	call := ptr.Args[0]            // The runtime.newobject call
   764  
   765  	if len(pending) == 1 {
   766  		// Just a single object, do a standard allocation.
   767  		v := pending[0]
   768  		v.Op = ssa.OpCopy // instead of OffPtr [0]
   769  		return
   770  	}
   771  
   772  	// Sort in decreasing alignment.
   773  	// This way we never have to worry about padding.
   774  	// (Stable not required; just cleaner to keep program order among equal alignments.)
   775  	slices.SortStableFunc(pending, func(x, y *ssa.Value) int {
   776  		return cmp.Compare(allocAlign(y.Type.Elem()), allocAlign(x.Type.Elem()))
   777  	})
   778  
   779  	// Figure out how much data we need allocate.
   780  	var size int64
   781  	for _, v := range pending {
   782  		v.AuxInt = size // Adjust OffPtr to the right value while we are here.
   783  		size += allocSize(v.Type.Elem())
   784  	}
   785  	align := allocAlign(pending[0].Type.Elem())
   786  	size = types.RoundUp(size, align)
   787  
   788  	// Convert newObject call to a mallocgc call.
   789  	args := []*ssa.Value{
   790  		s.constInt(types.Types[types.TUINTPTR], size),
   791  		s.constNil(call.Args[0].Type), // a nil *runtime._type
   792  		s.constBool(true),             // needZero TODO: false is ok?
   793  		call.Args[1],                  // memory
   794  	}
   795  	mallocSym := ir.Syms.MallocGC
   796  	if specialMallocSym := s.specializedMallocSym(size, false); specialMallocSym != nil {
   797  		mallocSym = specialMallocSym
   798  	}
   799  	call.Aux = ssa.StaticAuxCall(mallocSym, s.f.ABIDefault.ABIAnalyzeTypes(
   800  		[]*types.Type{args[0].Type, args[1].Type, args[2].Type},
   801  		[]*types.Type{types.Types[types.TUNSAFEPTR]},
   802  	))
   803  	call.AuxInt = 4 * s.config.PtrSize // arg+results size, uintptr/ptr/bool/ptr
   804  	call.SetArgs4(args[0], args[1], args[2], args[3])
   805  	// TODO: figure out how to pass alignment to runtime
   806  
   807  	call.Type = types.NewTuple(types.Types[types.TUNSAFEPTR], types.TypeMem)
   808  	ptr.Type = types.Types[types.TUNSAFEPTR]
   809  }
   810  
   811  func (s *state) specializedMallocSym(size int64, hasPointers bool) *obj.LSym {
   812  	if !s.sizeSpecializedMallocEnabled() {
   813  		return nil
   814  	}
   815  	const specializedMallocMax = 80 // This must match the constant in mkmalloc.
   816  	if size > specializedMallocMax {
   817  		return nil
   818  	}
   819  	divRoundUp := func(n, a uintptr) uintptr { return (n + a - 1) / a }
   820  	sizeClass := gc.SizeToSizeClass8[divRoundUp(uintptr(size), gc.SmallSizeDiv)]
   821  	if hasPointers {
   822  		return ir.Syms.MallocGCSmallScanNoHeader[sizeClass]
   823  	}
   824  	if size < gc.TinySize {
   825  		return ir.Syms.MallocGCTiny
   826  	}
   827  	return ir.Syms.MallocGCSmallNoScan[sizeClass]
   828  }
   829  
   830  func (s *state) sizeSpecializedMallocEnabled() bool {
   831  	if base.Flag.CompilingRuntime {
   832  		// The compiler forces the values of the asan, msan, and race flags to false if
   833  		// we're compiling the runtime, so we lose the information about whether we're
   834  		// building in asan, msan, or race mode. Because the specialized functions don't
   835  		// work in that mode, just turn if off in that case.
   836  		// TODO(matloob): Save the information about whether the flags were passed in
   837  		// originally so we can turn off size specialized malloc in that case instead
   838  		// using Instrumenting below. Then we can remove this condition.
   839  		return false
   840  	}
   841  
   842  	return !base.Flag.Cfg.Instrumenting
   843  }
   844  
   845  // setHeapaddr allocates a new PAUTO variable to store ptr (which must be non-nil)
   846  // and then sets it as n's heap address.
   847  func (s *state) setHeapaddr(pos src.XPos, n *ir.Name, ptr *ssa.Value) {
   848  	if !ptr.Type.IsPtr() || !types.Identical(n.Type(), ptr.Type.Elem()) {
   849  		base.FatalfAt(n.Pos(), "setHeapaddr %L with type %v", n, ptr.Type)
   850  	}
   851  
   852  	// Declare variable to hold address.
   853  	sym := &types.Sym{Name: "&" + n.Sym().Name, Pkg: types.LocalPkg}
   854  	addr := s.curfn.NewLocal(pos, sym, types.NewPtr(n.Type()))
   855  	addr.SetUsed(true)
   856  	types.CalcSize(addr.Type())
   857  
   858  	if n.Class == ir.PPARAMOUT {
   859  		addr.SetIsOutputParamHeapAddr(true)
   860  	}
   861  
   862  	n.Heapaddr = addr
   863  	s.assign(addr, ptr, false, 0)
   864  }
   865  
   866  // newObject returns an SSA value denoting new(typ).
   867  func (s *state) newObject(typ *types.Type) *ssa.Value {
   868  	if typ.Size() == 0 {
   869  		return s.newValue1A(ssa.OpAddr, types.NewPtr(typ), ir.Syms.Zerobase, s.sb)
   870  	}
   871  	rtype := s.reflectType(typ)
   872  	if specialMallocSym := s.specializedMallocSym(typ.Size(), typ.HasPointers()); specialMallocSym != nil {
   873  		return s.rtcall(specialMallocSym, true, []*types.Type{types.NewPtr(typ)},
   874  			s.constInt(types.Types[types.TUINTPTR], typ.Size()),
   875  			rtype,
   876  			s.constBool(true),
   877  		)[0]
   878  	}
   879  	return s.rtcall(ir.Syms.Newobject, true, []*types.Type{types.NewPtr(typ)}, rtype)[0]
   880  }
   881  
   882  // newObjectNonSpecialized returns an SSA value denoting new(typ). It does
   883  // not produce size-specialized malloc functions.
   884  func (s *state) newObjectNonSpecialized(typ *types.Type, rtype *ssa.Value) *ssa.Value {
   885  	if typ.Size() == 0 {
   886  		return s.newValue1A(ssa.OpAddr, types.NewPtr(typ), ir.Syms.Zerobase, s.sb)
   887  	}
   888  	if rtype == nil {
   889  		rtype = s.reflectType(typ)
   890  	}
   891  	return s.rtcall(ir.Syms.Newobject, true, []*types.Type{types.NewPtr(typ)}, rtype)[0]
   892  }
   893  
   894  func (s *state) checkPtrAlignment(n *ir.ConvExpr, v *ssa.Value, count *ssa.Value) {
   895  	if !n.Type().IsPtr() {
   896  		s.Fatalf("expected pointer type: %v", n.Type())
   897  	}
   898  	elem, rtypeExpr := n.Type().Elem(), n.ElemRType
   899  	if count != nil {
   900  		if !elem.IsArray() {
   901  			s.Fatalf("expected array type: %v", elem)
   902  		}
   903  		elem, rtypeExpr = elem.Elem(), n.ElemElemRType
   904  	}
   905  	size := elem.Size()
   906  	// Casting from larger type to smaller one is ok, so for smallest type, do nothing.
   907  	if elem.Alignment() == 1 && (size == 0 || size == 1 || count == nil) {
   908  		return
   909  	}
   910  	if count == nil {
   911  		count = s.constInt(types.Types[types.TUINTPTR], 1)
   912  	}
   913  	if count.Type.Size() != s.config.PtrSize {
   914  		s.Fatalf("expected count fit to a uintptr size, have: %d, want: %d", count.Type.Size(), s.config.PtrSize)
   915  	}
   916  	var rtype *ssa.Value
   917  	if rtypeExpr != nil {
   918  		rtype = s.expr(rtypeExpr)
   919  	} else {
   920  		rtype = s.reflectType(elem)
   921  	}
   922  	s.rtcall(ir.Syms.CheckPtrAlignment, true, nil, v, rtype, count)
   923  }
   924  
   925  // reflectType returns an SSA value representing a pointer to typ's
   926  // reflection type descriptor.
   927  func (s *state) reflectType(typ *types.Type) *ssa.Value {
   928  	// TODO(mdempsky): Make this Fatalf under Unified IR; frontend needs
   929  	// to supply RType expressions.
   930  	lsym := reflectdata.TypeLinksym(typ)
   931  	return s.entryNewValue1A(ssa.OpAddr, types.NewPtr(types.Types[types.TUINT8]), lsym, s.sb)
   932  }
   933  
   934  func dumpSourcesColumn(writer *ssa.HTMLWriter, fn *ir.Func) {
   935  	// Read sources of target function fn.
   936  	fname := base.Ctxt.PosTable.Pos(fn.Pos()).Filename()
   937  	targetFn, err := readFuncLines(fname, fn.Pos().Line(), fn.Endlineno.Line())
   938  	if err != nil {
   939  		writer.Logf("cannot read sources for function %v: %v", fn, err)
   940  	}
   941  
   942  	// Read sources of inlined functions.
   943  	var inlFns []*ssa.FuncLines
   944  	for _, fi := range ssaDumpInlined {
   945  		elno := fi.Endlineno
   946  		fname := base.Ctxt.PosTable.Pos(fi.Pos()).Filename()
   947  		fnLines, err := readFuncLines(fname, fi.Pos().Line(), elno.Line())
   948  		if err != nil {
   949  			writer.Logf("cannot read sources for inlined function %v: %v", fi, err)
   950  			continue
   951  		}
   952  		inlFns = append(inlFns, fnLines)
   953  	}
   954  
   955  	slices.SortFunc(inlFns, ssa.ByTopoCmp)
   956  	if targetFn != nil {
   957  		inlFns = append([]*ssa.FuncLines{targetFn}, inlFns...)
   958  	}
   959  
   960  	writer.WriteSources("sources", inlFns)
   961  }
   962  
   963  func readFuncLines(file string, start, end uint) (*ssa.FuncLines, error) {
   964  	f, err := os.Open(os.ExpandEnv(file))
   965  	if err != nil {
   966  		return nil, err
   967  	}
   968  	defer f.Close() // ignore error
   969  	var lines []string
   970  	ln := uint(1)
   971  	scanner := bufio.NewScanner(f)
   972  	for scanner.Scan() && ln <= end {
   973  		if ln >= start {
   974  			lines = append(lines, scanner.Text())
   975  		}
   976  		ln++
   977  	}
   978  	if err := scanner.Err(); err != nil {
   979  		return nil, fmt.Errorf("scanning %s: %v", file, err)
   980  	}
   981  	return &ssa.FuncLines{Filename: file, StartLineno: start, Lines: lines}, nil
   982  }
   983  
   984  // updateUnsetPredPos propagates the earliest-value position information for b
   985  // towards all of b's predecessors that need a position, and recurs on that
   986  // predecessor if its position is updated. B should have a non-empty position.
   987  func (s *state) updateUnsetPredPos(b *ssa.Block) {
   988  	if b.Pos == src.NoXPos {
   989  		s.Fatalf("Block %s should have a position", b)
   990  	}
   991  	bestPos := src.NoXPos
   992  	for _, e := range b.Preds {
   993  		p := e.Block()
   994  		if !p.LackingPos() {
   995  			continue
   996  		}
   997  		if bestPos == src.NoXPos {
   998  			bestPos = b.Pos
   999  			for _, v := range b.Values {
  1000  				if v.LackingPos() {
  1001  					continue
  1002  				}
  1003  				if v.Pos != src.NoXPos {
  1004  					// Assume values are still in roughly textual order;
  1005  					// TODO: could also seek minimum position?
  1006  					bestPos = v.Pos
  1007  					break
  1008  				}
  1009  			}
  1010  		}
  1011  		p.Pos = bestPos
  1012  		s.updateUnsetPredPos(p) // We do not expect long chains of these, thus recursion is okay.
  1013  	}
  1014  }
  1015  
  1016  // Information about each open-coded defer.
  1017  type openDeferInfo struct {
  1018  	// The node representing the call of the defer
  1019  	n *ir.CallExpr
  1020  	// If defer call is closure call, the address of the argtmp where the
  1021  	// closure is stored.
  1022  	closure *ssa.Value
  1023  	// The node representing the argtmp where the closure is stored - used for
  1024  	// function, method, or interface call, to store a closure that panic
  1025  	// processing can use for this defer.
  1026  	closureNode *ir.Name
  1027  }
  1028  
  1029  type state struct {
  1030  	// configuration (arch) information
  1031  	config *ssa.Config
  1032  
  1033  	// function we're building
  1034  	f *ssa.Func
  1035  
  1036  	// Node for function
  1037  	curfn *ir.Func
  1038  
  1039  	// labels in f
  1040  	labels map[string]*ssaLabel
  1041  
  1042  	// unlabeled break and continue statement tracking
  1043  	breakTo    *ssa.Block // current target for plain break statement
  1044  	continueTo *ssa.Block // current target for plain continue statement
  1045  
  1046  	// current location where we're interpreting the AST
  1047  	curBlock *ssa.Block
  1048  
  1049  	// variable assignments in the current block (map from variable symbol to ssa value)
  1050  	// *Node is the unique identifier (an ONAME Node) for the variable.
  1051  	// TODO: keep a single varnum map, then make all of these maps slices instead?
  1052  	vars map[ir.Node]*ssa.Value
  1053  
  1054  	// fwdVars are variables that are used before they are defined in the current block.
  1055  	// This map exists just to coalesce multiple references into a single FwdRef op.
  1056  	// *Node is the unique identifier (an ONAME Node) for the variable.
  1057  	fwdVars map[ir.Node]*ssa.Value
  1058  
  1059  	// all defined variables at the end of each block. Indexed by block ID.
  1060  	defvars []map[ir.Node]*ssa.Value
  1061  
  1062  	// addresses of PPARAM and PPARAMOUT variables on the stack.
  1063  	decladdrs map[*ir.Name]*ssa.Value
  1064  
  1065  	// starting values. Memory, stack pointer, and globals pointer
  1066  	startmem *ssa.Value
  1067  	sp       *ssa.Value
  1068  	sb       *ssa.Value
  1069  	// value representing address of where deferBits autotmp is stored
  1070  	deferBitsAddr *ssa.Value
  1071  	deferBitsTemp *ir.Name
  1072  
  1073  	// line number stack. The current line number is top of stack
  1074  	line []src.XPos
  1075  	// the last line number processed; it may have been popped
  1076  	lastPos src.XPos
  1077  
  1078  	// list of panic calls by function name and line number.
  1079  	// Used to deduplicate panic calls.
  1080  	panics map[funcLine]*ssa.Block
  1081  
  1082  	cgoUnsafeArgs       bool
  1083  	hasdefer            bool // whether the function contains a defer statement
  1084  	softFloat           bool
  1085  	hasOpenDefers       bool // whether we are doing open-coded defers
  1086  	checkPtrEnabled     bool // whether to insert checkptr instrumentation
  1087  	instrumentEnterExit bool // whether to instrument function enter/exit
  1088  	instrumentMemory    bool // whether to instrument memory operations
  1089  
  1090  	// If doing open-coded defers, list of info about the defer calls in
  1091  	// scanning order. Hence, at exit we should run these defers in reverse
  1092  	// order of this list
  1093  	openDefers []*openDeferInfo
  1094  	// For open-coded defers, this is the beginning and end blocks of the last
  1095  	// defer exit code that we have generated so far. We use these to share
  1096  	// code between exits if the shareDeferExits option (disabled by default)
  1097  	// is on.
  1098  	lastDeferExit       *ssa.Block // Entry block of last defer exit code we generated
  1099  	lastDeferFinalBlock *ssa.Block // Final block of last defer exit code we generated
  1100  	lastDeferCount      int        // Number of defers encountered at that point
  1101  
  1102  	prevCall *ssa.Value // the previous call; use this to tie results to the call op.
  1103  
  1104  	// List of allocations in the current block that are still pending.
  1105  	// They are all (OffPtr (Select0 (runtime call))) and have the correct types,
  1106  	// but the offsets are not set yet, and the type of the runtime call is also not final.
  1107  	pendingHeapAllocations []*ssa.Value
  1108  
  1109  	// First argument of append calls that could be stack allocated.
  1110  	appendTargets map[ir.Node]bool
  1111  
  1112  	// Block starting position, indexed by block id.
  1113  	blockStarts []src.XPos
  1114  
  1115  	// Information for stack allocation. Indexed by the first argument
  1116  	// to an append call. Normally a slice-typed variable, but not always.
  1117  	backingStores map[ir.Node]*backingStoreInfo
  1118  }
  1119  
  1120  type backingStoreInfo struct {
  1121  	// Size of backing store array (in elements)
  1122  	K int64
  1123  	// Stack-allocated backing store variable.
  1124  	store *ir.Name
  1125  	// Dynamic boolean variable marking the fact that we used this backing store.
  1126  	used *ir.Name
  1127  	// Have we used this variable statically yet? This is just a hint
  1128  	// to avoid checking the dynamic variable if the answer is obvious.
  1129  	// (usedStatic == true implies used == true)
  1130  	usedStatic bool
  1131  }
  1132  
  1133  type funcLine struct {
  1134  	f    *obj.LSym
  1135  	base *src.PosBase
  1136  	line uint
  1137  }
  1138  
  1139  type ssaLabel struct {
  1140  	target         *ssa.Block // block identified by this label
  1141  	breakTarget    *ssa.Block // block to break to in control flow node identified by this label
  1142  	continueTarget *ssa.Block // block to continue to in control flow node identified by this label
  1143  }
  1144  
  1145  // label returns the label associated with sym, creating it if necessary.
  1146  func (s *state) label(sym *types.Sym) *ssaLabel {
  1147  	lab := s.labels[sym.Name]
  1148  	if lab == nil {
  1149  		lab = new(ssaLabel)
  1150  		s.labels[sym.Name] = lab
  1151  	}
  1152  	return lab
  1153  }
  1154  
  1155  func (s *state) Logf(msg string, args ...any) { s.f.Logf(msg, args...) }
  1156  func (s *state) Log() bool                    { return s.f.Log() }
  1157  func (s *state) Fatalf(msg string, args ...any) {
  1158  	s.f.Frontend().Fatalf(s.peekPos(), msg, args...)
  1159  }
  1160  func (s *state) Warnl(pos src.XPos, msg string, args ...any) { s.f.Warnl(pos, msg, args...) }
  1161  func (s *state) Debug_checknil() bool                        { return s.f.Frontend().Debug_checknil() }
  1162  
  1163  func ssaMarker(name string) *ir.Name {
  1164  	return ir.NewNameAt(base.Pos, &types.Sym{Name: name}, nil)
  1165  }
  1166  
  1167  var (
  1168  	// marker node for the memory variable
  1169  	memVar = ssaMarker("mem")
  1170  
  1171  	// marker nodes for temporary variables
  1172  	ptrVar       = ssaMarker("ptr")
  1173  	lenVar       = ssaMarker("len")
  1174  	capVar       = ssaMarker("cap")
  1175  	typVar       = ssaMarker("typ")
  1176  	okVar        = ssaMarker("ok")
  1177  	deferBitsVar = ssaMarker("deferBits")
  1178  	hashVar      = ssaMarker("hash")
  1179  )
  1180  
  1181  // startBlock sets the current block we're generating code in to b.
  1182  func (s *state) startBlock(b *ssa.Block) {
  1183  	if s.curBlock != nil {
  1184  		s.Fatalf("starting block %v when block %v has not ended", b, s.curBlock)
  1185  	}
  1186  	s.curBlock = b
  1187  	s.vars = map[ir.Node]*ssa.Value{}
  1188  	clear(s.fwdVars)
  1189  	for len(s.blockStarts) <= int(b.ID) {
  1190  		s.blockStarts = append(s.blockStarts, src.NoXPos)
  1191  	}
  1192  }
  1193  
  1194  // endBlock marks the end of generating code for the current block.
  1195  // Returns the (former) current block. Returns nil if there is no current
  1196  // block, i.e. if no code flows to the current execution point.
  1197  func (s *state) endBlock() *ssa.Block {
  1198  	b := s.curBlock
  1199  	if b == nil {
  1200  		return nil
  1201  	}
  1202  
  1203  	s.flushPendingHeapAllocations()
  1204  
  1205  	for len(s.defvars) <= int(b.ID) {
  1206  		s.defvars = append(s.defvars, nil)
  1207  	}
  1208  	s.defvars[b.ID] = s.vars
  1209  	s.curBlock = nil
  1210  	s.vars = nil
  1211  	if b.LackingPos() {
  1212  		// Empty plain blocks get the line of their successor (handled after all blocks created),
  1213  		// except for increment blocks in For statements (handled in ssa conversion of OFOR),
  1214  		// and for blocks ending in GOTO/BREAK/CONTINUE.
  1215  		b.Pos = src.NoXPos
  1216  	} else {
  1217  		b.Pos = s.lastPos
  1218  		if s.blockStarts[b.ID] == src.NoXPos {
  1219  			s.blockStarts[b.ID] = s.lastPos
  1220  		}
  1221  	}
  1222  	return b
  1223  }
  1224  
  1225  // pushLine pushes a line number on the line number stack.
  1226  func (s *state) pushLine(line src.XPos) {
  1227  	if !line.IsKnown() {
  1228  		// the frontend may emit node with line number missing,
  1229  		// use the parent line number in this case.
  1230  		line = s.peekPos()
  1231  		if base.Flag.K != 0 {
  1232  			base.Warn("buildssa: unknown position (line 0)")
  1233  		}
  1234  	} else {
  1235  		s.lastPos = line
  1236  	}
  1237  	// The first position we see for a new block is its starting position
  1238  	// (the line number for its phis, if any).
  1239  	if b := s.curBlock; b != nil && s.blockStarts[b.ID] == src.NoXPos {
  1240  		s.blockStarts[b.ID] = line
  1241  	}
  1242  
  1243  	s.line = append(s.line, line)
  1244  }
  1245  
  1246  // popLine pops the top of the line number stack.
  1247  func (s *state) popLine() {
  1248  	s.line = s.line[:len(s.line)-1]
  1249  }
  1250  
  1251  // peekPos peeks the top of the line number stack.
  1252  func (s *state) peekPos() src.XPos {
  1253  	return s.line[len(s.line)-1]
  1254  }
  1255  
  1256  // newValue0 adds a new value with no arguments to the current block.
  1257  func (s *state) newValue0(op ssa.Op, t *types.Type) *ssa.Value {
  1258  	return s.curBlock.NewValue0(s.peekPos(), op, t)
  1259  }
  1260  
  1261  // newValue0A adds a new value with no arguments and an aux value to the current block.
  1262  func (s *state) newValue0A(op ssa.Op, t *types.Type, aux ssa.Aux) *ssa.Value {
  1263  	return s.curBlock.NewValue0A(s.peekPos(), op, t, aux)
  1264  }
  1265  
  1266  // newValue0I adds a new value with no arguments and an auxint value to the current block.
  1267  func (s *state) newValue0I(op ssa.Op, t *types.Type, auxint int64) *ssa.Value {
  1268  	return s.curBlock.NewValue0I(s.peekPos(), op, t, auxint)
  1269  }
  1270  
  1271  // newValue1 adds a new value with one argument to the current block.
  1272  func (s *state) newValue1(op ssa.Op, t *types.Type, arg *ssa.Value) *ssa.Value {
  1273  	return s.curBlock.NewValue1(s.peekPos(), op, t, arg)
  1274  }
  1275  
  1276  // newValue1A adds a new value with one argument and an aux value to the current block.
  1277  func (s *state) newValue1A(op ssa.Op, t *types.Type, aux ssa.Aux, arg *ssa.Value) *ssa.Value {
  1278  	return s.curBlock.NewValue1A(s.peekPos(), op, t, aux, arg)
  1279  }
  1280  
  1281  // newValue1Apos adds a new value with one argument and an aux value to the current block.
  1282  // isStmt determines whether the created values may be a statement or not
  1283  // (i.e., false means never, yes means maybe).
  1284  func (s *state) newValue1Apos(op ssa.Op, t *types.Type, aux ssa.Aux, arg *ssa.Value, isStmt bool) *ssa.Value {
  1285  	if isStmt {
  1286  		return s.curBlock.NewValue1A(s.peekPos(), op, t, aux, arg)
  1287  	}
  1288  	return s.curBlock.NewValue1A(s.peekPos().WithNotStmt(), op, t, aux, arg)
  1289  }
  1290  
  1291  // newValue1I adds a new value with one argument and an auxint value to the current block.
  1292  func (s *state) newValue1I(op ssa.Op, t *types.Type, aux int64, arg *ssa.Value) *ssa.Value {
  1293  	return s.curBlock.NewValue1I(s.peekPos(), op, t, aux, arg)
  1294  }
  1295  
  1296  // newValue2 adds a new value with two arguments to the current block.
  1297  func (s *state) newValue2(op ssa.Op, t *types.Type, arg0, arg1 *ssa.Value) *ssa.Value {
  1298  	return s.curBlock.NewValue2(s.peekPos(), op, t, arg0, arg1)
  1299  }
  1300  
  1301  // newValue2A adds a new value with two arguments and an aux value to the current block.
  1302  func (s *state) newValue2A(op ssa.Op, t *types.Type, aux ssa.Aux, arg0, arg1 *ssa.Value) *ssa.Value {
  1303  	return s.curBlock.NewValue2A(s.peekPos(), op, t, aux, arg0, arg1)
  1304  }
  1305  
  1306  // newValue2Apos adds a new value with two arguments and an aux value to the current block.
  1307  // isStmt determines whether the created values may be a statement or not
  1308  // (i.e., false means never, yes means maybe).
  1309  func (s *state) newValue2Apos(op ssa.Op, t *types.Type, aux ssa.Aux, arg0, arg1 *ssa.Value, isStmt bool) *ssa.Value {
  1310  	if isStmt {
  1311  		return s.curBlock.NewValue2A(s.peekPos(), op, t, aux, arg0, arg1)
  1312  	}
  1313  	return s.curBlock.NewValue2A(s.peekPos().WithNotStmt(), op, t, aux, arg0, arg1)
  1314  }
  1315  
  1316  // newValue2I adds a new value with two arguments and an auxint value to the current block.
  1317  func (s *state) newValue2I(op ssa.Op, t *types.Type, aux int64, arg0, arg1 *ssa.Value) *ssa.Value {
  1318  	return s.curBlock.NewValue2I(s.peekPos(), op, t, aux, arg0, arg1)
  1319  }
  1320  
  1321  // newValue3 adds a new value with three arguments to the current block.
  1322  func (s *state) newValue3(op ssa.Op, t *types.Type, arg0, arg1, arg2 *ssa.Value) *ssa.Value {
  1323  	return s.curBlock.NewValue3(s.peekPos(), op, t, arg0, arg1, arg2)
  1324  }
  1325  
  1326  // newValue3I adds a new value with three arguments and an auxint value to the current block.
  1327  func (s *state) newValue3I(op ssa.Op, t *types.Type, aux int64, arg0, arg1, arg2 *ssa.Value) *ssa.Value {
  1328  	return s.curBlock.NewValue3I(s.peekPos(), op, t, aux, arg0, arg1, arg2)
  1329  }
  1330  
  1331  // newValue3A adds a new value with three arguments and an aux value to the current block.
  1332  func (s *state) newValue3A(op ssa.Op, t *types.Type, aux ssa.Aux, arg0, arg1, arg2 *ssa.Value) *ssa.Value {
  1333  	return s.curBlock.NewValue3A(s.peekPos(), op, t, aux, arg0, arg1, arg2)
  1334  }
  1335  
  1336  // newValue3Apos adds a new value with three arguments and an aux value to the current block.
  1337  // isStmt determines whether the created values may be a statement or not
  1338  // (i.e., false means never, yes means maybe).
  1339  func (s *state) newValue3Apos(op ssa.Op, t *types.Type, aux ssa.Aux, arg0, arg1, arg2 *ssa.Value, isStmt bool) *ssa.Value {
  1340  	if isStmt {
  1341  		return s.curBlock.NewValue3A(s.peekPos(), op, t, aux, arg0, arg1, arg2)
  1342  	}
  1343  	return s.curBlock.NewValue3A(s.peekPos().WithNotStmt(), op, t, aux, arg0, arg1, arg2)
  1344  }
  1345  
  1346  // newValue4 adds a new value with four arguments to the current block.
  1347  func (s *state) newValue4(op ssa.Op, t *types.Type, arg0, arg1, arg2, arg3 *ssa.Value) *ssa.Value {
  1348  	return s.curBlock.NewValue4(s.peekPos(), op, t, arg0, arg1, arg2, arg3)
  1349  }
  1350  
  1351  // newValue4A adds a new value with four arguments and an aux value to the current block.
  1352  func (s *state) newValue4A(op ssa.Op, t *types.Type, aux ssa.Aux, arg0, arg1, arg2, arg3 *ssa.Value) *ssa.Value {
  1353  	return s.curBlock.NewValue4A(s.peekPos(), op, t, aux, arg0, arg1, arg2, arg3)
  1354  }
  1355  
  1356  // newValue4I adds a new value with four arguments and an auxint value to the current block.
  1357  func (s *state) newValue4I(op ssa.Op, t *types.Type, aux int64, arg0, arg1, arg2, arg3 *ssa.Value) *ssa.Value {
  1358  	return s.curBlock.NewValue4I(s.peekPos(), op, t, aux, arg0, arg1, arg2, arg3)
  1359  }
  1360  
  1361  func (s *state) entryBlock() *ssa.Block {
  1362  	b := s.f.Entry
  1363  	if base.Flag.N > 0 && s.curBlock != nil {
  1364  		// If optimizations are off, allocate in current block instead. Since with -N
  1365  		// we're not doing the CSE or tighten passes, putting lots of stuff in the
  1366  		// entry block leads to O(n^2) entries in the live value map during regalloc.
  1367  		// See issue 45897.
  1368  		b = s.curBlock
  1369  	}
  1370  	return b
  1371  }
  1372  
  1373  // entryNewValue0 adds a new value with no arguments to the entry block.
  1374  func (s *state) entryNewValue0(op ssa.Op, t *types.Type) *ssa.Value {
  1375  	return s.entryBlock().NewValue0(src.NoXPos, op, t)
  1376  }
  1377  
  1378  // entryNewValue0A adds a new value with no arguments and an aux value to the entry block.
  1379  func (s *state) entryNewValue0A(op ssa.Op, t *types.Type, aux ssa.Aux) *ssa.Value {
  1380  	return s.entryBlock().NewValue0A(src.NoXPos, op, t, aux)
  1381  }
  1382  
  1383  // entryNewValue1 adds a new value with one argument to the entry block.
  1384  func (s *state) entryNewValue1(op ssa.Op, t *types.Type, arg *ssa.Value) *ssa.Value {
  1385  	return s.entryBlock().NewValue1(src.NoXPos, op, t, arg)
  1386  }
  1387  
  1388  // entryNewValue1I adds a new value with one argument and an auxint value to the entry block.
  1389  func (s *state) entryNewValue1I(op ssa.Op, t *types.Type, auxint int64, arg *ssa.Value) *ssa.Value {
  1390  	return s.entryBlock().NewValue1I(src.NoXPos, op, t, auxint, arg)
  1391  }
  1392  
  1393  // entryNewValue1A adds a new value with one argument and an aux value to the entry block.
  1394  func (s *state) entryNewValue1A(op ssa.Op, t *types.Type, aux ssa.Aux, arg *ssa.Value) *ssa.Value {
  1395  	return s.entryBlock().NewValue1A(src.NoXPos, op, t, aux, arg)
  1396  }
  1397  
  1398  // entryNewValue2 adds a new value with two arguments to the entry block.
  1399  func (s *state) entryNewValue2(op ssa.Op, t *types.Type, arg0, arg1 *ssa.Value) *ssa.Value {
  1400  	return s.entryBlock().NewValue2(src.NoXPos, op, t, arg0, arg1)
  1401  }
  1402  
  1403  // entryNewValue2A adds a new value with two arguments and an aux value to the entry block.
  1404  func (s *state) entryNewValue2A(op ssa.Op, t *types.Type, aux ssa.Aux, arg0, arg1 *ssa.Value) *ssa.Value {
  1405  	return s.entryBlock().NewValue2A(src.NoXPos, op, t, aux, arg0, arg1)
  1406  }
  1407  
  1408  // const* routines add a new const value to the entry block.
  1409  func (s *state) constSlice(t *types.Type) *ssa.Value {
  1410  	return s.f.ConstSlice(t)
  1411  }
  1412  func (s *state) constInterface(t *types.Type) *ssa.Value {
  1413  	return s.f.ConstInterface(t)
  1414  }
  1415  func (s *state) constNil(t *types.Type) *ssa.Value { return s.f.ConstNil(t) }
  1416  func (s *state) constEmptyString(t *types.Type) *ssa.Value {
  1417  	return s.f.ConstEmptyString(t)
  1418  }
  1419  func (s *state) constBool(c bool) *ssa.Value {
  1420  	return s.f.ConstBool(types.Types[types.TBOOL], c)
  1421  }
  1422  func (s *state) constInt8(t *types.Type, c int8) *ssa.Value {
  1423  	return s.f.ConstInt8(t, c)
  1424  }
  1425  func (s *state) constInt16(t *types.Type, c int16) *ssa.Value {
  1426  	return s.f.ConstInt16(t, c)
  1427  }
  1428  func (s *state) constInt32(t *types.Type, c int32) *ssa.Value {
  1429  	return s.f.ConstInt32(t, c)
  1430  }
  1431  func (s *state) constInt64(t *types.Type, c int64) *ssa.Value {
  1432  	return s.f.ConstInt64(t, c)
  1433  }
  1434  func (s *state) constFloat32(t *types.Type, c float64) *ssa.Value {
  1435  	return s.f.ConstFloat32(t, c)
  1436  }
  1437  func (s *state) constFloat64(t *types.Type, c float64) *ssa.Value {
  1438  	return s.f.ConstFloat64(t, c)
  1439  }
  1440  func (s *state) constInt(t *types.Type, c int64) *ssa.Value {
  1441  	if s.config.PtrSize == 8 {
  1442  		return s.constInt64(t, c)
  1443  	}
  1444  	if int64(int32(c)) != c {
  1445  		s.Fatalf("integer constant too big %d", c)
  1446  	}
  1447  	return s.constInt32(t, int32(c))
  1448  }
  1449  
  1450  // newValueOrSfCall* are wrappers around newValue*, which may create a call to a
  1451  // soft-float runtime function instead (when emitting soft-float code).
  1452  func (s *state) newValueOrSfCall1(op ssa.Op, t *types.Type, arg *ssa.Value) *ssa.Value {
  1453  	if s.softFloat {
  1454  		if c, ok := s.sfcall(op, arg); ok {
  1455  			return c
  1456  		}
  1457  	}
  1458  	return s.newValue1(op, t, arg)
  1459  }
  1460  func (s *state) newValueOrSfCall2(op ssa.Op, t *types.Type, arg0, arg1 *ssa.Value) *ssa.Value {
  1461  	if s.softFloat {
  1462  		if c, ok := s.sfcall(op, arg0, arg1); ok {
  1463  			return c
  1464  		}
  1465  	}
  1466  	return s.newValue2(op, t, arg0, arg1)
  1467  }
  1468  
  1469  type instrumentKind uint8
  1470  
  1471  const (
  1472  	instrumentRead = iota
  1473  	instrumentWrite
  1474  	instrumentMove
  1475  )
  1476  
  1477  func (s *state) instrument(t *types.Type, addr *ssa.Value, kind instrumentKind) {
  1478  	s.instrument2(t, addr, nil, kind)
  1479  }
  1480  
  1481  // instrumentFields instruments a read/write operation on addr.
  1482  // If it is instrumenting for MSAN or ASAN and t is a struct type, it instruments
  1483  // operation for each field, instead of for the whole struct.
  1484  func (s *state) instrumentFields(t *types.Type, addr *ssa.Value, kind instrumentKind) {
  1485  	if !(base.Flag.MSan || base.Flag.ASan) || !isStructNotSIMD(t) {
  1486  		s.instrument(t, addr, kind)
  1487  		return
  1488  	}
  1489  	for _, f := range t.Fields() {
  1490  		if f.Sym.IsBlank() {
  1491  			continue
  1492  		}
  1493  		offptr := s.newValue1I(ssa.OpOffPtr, types.NewPtr(f.Type), f.Offset, addr)
  1494  		s.instrumentFields(f.Type, offptr, kind)
  1495  	}
  1496  }
  1497  
  1498  func (s *state) instrumentMove(t *types.Type, dst, src *ssa.Value) {
  1499  	if base.Flag.MSan {
  1500  		s.instrument2(t, dst, src, instrumentMove)
  1501  	} else {
  1502  		s.instrument(t, src, instrumentRead)
  1503  		s.instrument(t, dst, instrumentWrite)
  1504  	}
  1505  }
  1506  
  1507  func (s *state) instrument2(t *types.Type, addr, addr2 *ssa.Value, kind instrumentKind) {
  1508  	if !s.instrumentMemory {
  1509  		return
  1510  	}
  1511  
  1512  	w := t.Size()
  1513  	if w == 0 {
  1514  		return // can't race on zero-sized things
  1515  	}
  1516  
  1517  	if ssa.IsSanitizerSafeAddr(addr) {
  1518  		return
  1519  	}
  1520  
  1521  	var fn *obj.LSym
  1522  	needWidth := false
  1523  
  1524  	if addr2 != nil && kind != instrumentMove {
  1525  		panic("instrument2: non-nil addr2 for non-move instrumentation")
  1526  	}
  1527  
  1528  	if base.Flag.MSan {
  1529  		switch kind {
  1530  		case instrumentRead:
  1531  			fn = ir.Syms.Msanread
  1532  		case instrumentWrite:
  1533  			fn = ir.Syms.Msanwrite
  1534  		case instrumentMove:
  1535  			fn = ir.Syms.Msanmove
  1536  		default:
  1537  			panic("unreachable")
  1538  		}
  1539  		needWidth = true
  1540  	} else if base.Flag.Race && t.NumComponents(types.CountBlankFields) > 1 {
  1541  		// for composite objects we have to write every address
  1542  		// because a write might happen to any subobject.
  1543  		// composites with only one element don't have subobjects, though.
  1544  		switch kind {
  1545  		case instrumentRead:
  1546  			fn = ir.Syms.Racereadrange
  1547  		case instrumentWrite:
  1548  			fn = ir.Syms.Racewriterange
  1549  		default:
  1550  			panic("unreachable")
  1551  		}
  1552  		needWidth = true
  1553  	} else if base.Flag.Race {
  1554  		// for non-composite objects we can write just the start
  1555  		// address, as any write must write the first byte.
  1556  		switch kind {
  1557  		case instrumentRead:
  1558  			fn = ir.Syms.Raceread
  1559  		case instrumentWrite:
  1560  			fn = ir.Syms.Racewrite
  1561  		default:
  1562  			panic("unreachable")
  1563  		}
  1564  	} else if base.Flag.ASan {
  1565  		switch kind {
  1566  		case instrumentRead:
  1567  			fn = ir.Syms.Asanread
  1568  		case instrumentWrite:
  1569  			fn = ir.Syms.Asanwrite
  1570  		default:
  1571  			panic("unreachable")
  1572  		}
  1573  		needWidth = true
  1574  	} else {
  1575  		panic("unreachable")
  1576  	}
  1577  
  1578  	args := []*ssa.Value{addr}
  1579  	if addr2 != nil {
  1580  		args = append(args, addr2)
  1581  	}
  1582  	if needWidth {
  1583  		args = append(args, s.constInt(types.Types[types.TUINTPTR], w))
  1584  	}
  1585  	s.rtcall(fn, true, nil, args...)
  1586  }
  1587  
  1588  func (s *state) load(t *types.Type, src *ssa.Value) *ssa.Value {
  1589  	s.instrumentFields(t, src, instrumentRead)
  1590  	return s.rawLoad(t, src)
  1591  }
  1592  
  1593  func (s *state) rawLoad(t *types.Type, src *ssa.Value) *ssa.Value {
  1594  	return s.newValue2(ssa.OpLoad, t, src, s.mem())
  1595  }
  1596  
  1597  func (s *state) store(t *types.Type, dst, val *ssa.Value) {
  1598  	s.vars[memVar] = s.newValue3A(ssa.OpStore, types.TypeMem, t, dst, val, s.mem())
  1599  }
  1600  
  1601  func (s *state) zero(t *types.Type, dst *ssa.Value) {
  1602  	s.instrument(t, dst, instrumentWrite)
  1603  	store := s.newValue2I(ssa.OpZero, types.TypeMem, t.Size(), dst, s.mem())
  1604  	store.Aux = t
  1605  	s.vars[memVar] = store
  1606  }
  1607  
  1608  func (s *state) move(t *types.Type, dst, src *ssa.Value) {
  1609  	s.moveWhichMayOverlap(t, dst, src, false)
  1610  }
  1611  func (s *state) moveWhichMayOverlap(t *types.Type, dst, src *ssa.Value, mayOverlap bool) {
  1612  	s.instrumentMove(t, dst, src)
  1613  	if mayOverlap && t.IsArray() && t.NumElem() > 1 && !ssa.IsInlinableMemmove(dst, src, t.Size(), s.f.Config) {
  1614  		// Normally, when moving Go values of type T from one location to another,
  1615  		// we don't need to worry about partial overlaps. The two Ts must either be
  1616  		// in disjoint (nonoverlapping) memory or in exactly the same location.
  1617  		// There are 2 cases where this isn't true:
  1618  		//  1) Using unsafe you can arrange partial overlaps.
  1619  		//  2) Since Go 1.17, you can use a cast from a slice to a ptr-to-array.
  1620  		//     https://go.dev/ref/spec#Conversions_from_slice_to_array_pointer
  1621  		//     This feature can be used to construct partial overlaps of array types.
  1622  		//       var a [3]int
  1623  		//       p := (*[2]int)(a[:])
  1624  		//       q := (*[2]int)(a[1:])
  1625  		//       *p = *q
  1626  		// We don't care about solving 1. Or at least, we haven't historically
  1627  		// and no one has complained.
  1628  		// For 2, we need to ensure that if there might be partial overlap,
  1629  		// then we can't use OpMove; we must use memmove instead.
  1630  		// (memmove handles partial overlap by copying in the correct
  1631  		// direction. OpMove does not.)
  1632  		//
  1633  		// Note that we have to be careful here not to introduce a call when
  1634  		// we're marshaling arguments to a call or unmarshaling results from a call.
  1635  		// Cases where this is happening must pass mayOverlap to false.
  1636  		// (Currently this only happens when unmarshaling results of a call.)
  1637  		if t.HasPointers() {
  1638  			s.rtcall(ir.Syms.Typedmemmove, true, nil, s.reflectType(t), dst, src)
  1639  			// We would have otherwise implemented this move with straightline code,
  1640  			// including a write barrier. Pretend we issue a write barrier here,
  1641  			// so that the write barrier tests work. (Otherwise they'd need to know
  1642  			// the details of IsInlineableMemmove.)
  1643  			s.curfn.SetWBPos(s.peekPos())
  1644  		} else {
  1645  			s.rtcall(ir.Syms.Memmove, true, nil, dst, src, s.constInt(types.Types[types.TUINTPTR], t.Size()))
  1646  		}
  1647  		ssa.LogLargeCopy(s.f.Name, s.peekPos(), t.Size())
  1648  		return
  1649  	}
  1650  	store := s.newValue3I(ssa.OpMove, types.TypeMem, t.Size(), dst, src, s.mem())
  1651  	store.Aux = t
  1652  	s.vars[memVar] = store
  1653  }
  1654  
  1655  // stmtList converts the statement list n to SSA and adds it to s.
  1656  func (s *state) stmtList(l ir.Nodes) {
  1657  	for _, n := range l {
  1658  		s.stmt(n)
  1659  	}
  1660  }
  1661  
  1662  func peelConvNop(n ir.Node) ir.Node {
  1663  	if n == nil {
  1664  		return n
  1665  	}
  1666  	for n.Op() == ir.OCONVNOP {
  1667  		n = n.(*ir.ConvExpr).X
  1668  	}
  1669  	return n
  1670  }
  1671  
  1672  // stmt converts the statement n to SSA and adds it to s.
  1673  func (s *state) stmt(n ir.Node) {
  1674  	s.pushLine(n.Pos())
  1675  	defer s.popLine()
  1676  
  1677  	// If s.curBlock is nil, and n isn't a label (which might have an associated goto somewhere),
  1678  	// then this code is dead. Stop here.
  1679  	if s.curBlock == nil && n.Op() != ir.OLABEL {
  1680  		return
  1681  	}
  1682  
  1683  	s.stmtList(n.Init())
  1684  	switch n.Op() {
  1685  
  1686  	case ir.OBLOCK:
  1687  		n := n.(*ir.BlockStmt)
  1688  		s.stmtList(n.List)
  1689  
  1690  	case ir.OFALL: // no-op
  1691  
  1692  	// Expression statements
  1693  	case ir.OCALLFUNC:
  1694  		n := n.(*ir.CallExpr)
  1695  		if ir.IsIntrinsicCall(n) {
  1696  			s.intrinsicCall(n)
  1697  			return
  1698  		}
  1699  		fallthrough
  1700  
  1701  	case ir.OCALLINTER:
  1702  		n := n.(*ir.CallExpr)
  1703  		s.callResult(n, callNormal)
  1704  		if n.Op() == ir.OCALLFUNC && n.Fun.Op() == ir.ONAME && n.Fun.(*ir.Name).Class == ir.PFUNC {
  1705  			if fn := n.Fun.Sym().Name; base.Flag.CompilingRuntime && fn == "throw" ||
  1706  				n.Fun.Sym().Pkg == ir.Pkgs.Runtime &&
  1707  					(fn == "throwinit" || fn == "gopanic" || fn == "panicwrap" || fn == "block" ||
  1708  						fn == "panicmakeslicelen" || fn == "panicmakeslicecap" || fn == "panicunsafeslicelen" ||
  1709  						fn == "panicunsafeslicenilptr" || fn == "panicunsafestringlen" || fn == "panicunsafestringnilptr" ||
  1710  						fn == "panicrangestate") {
  1711  				m := s.mem()
  1712  				b := s.endBlock()
  1713  				b.Kind = block.BlockExit
  1714  				b.SetControl(m)
  1715  				// TODO: never rewrite OPANIC to OCALLFUNC in the
  1716  				// first place. Need to wait until all backends
  1717  				// go through SSA.
  1718  			}
  1719  		}
  1720  	case ir.ODEFER:
  1721  		n := n.(*ir.GoDeferStmt)
  1722  		if base.Debug.Defer > 0 {
  1723  			var defertype string
  1724  			if s.hasOpenDefers {
  1725  				defertype = "open-coded"
  1726  			} else if n.Esc() == ir.EscNever {
  1727  				defertype = "stack-allocated"
  1728  			} else {
  1729  				defertype = "heap-allocated"
  1730  			}
  1731  			base.WarnfAt(n.Pos(), "%s defer", defertype)
  1732  		}
  1733  		if s.hasOpenDefers {
  1734  			s.openDeferRecord(n.Call.(*ir.CallExpr))
  1735  		} else {
  1736  			d := callDefer
  1737  			if n.Esc() == ir.EscNever && n.DeferAt == nil {
  1738  				d = callDeferStack
  1739  			}
  1740  			s.call(n.Call.(*ir.CallExpr), d, false, n.DeferAt)
  1741  		}
  1742  	case ir.OGO:
  1743  		n := n.(*ir.GoDeferStmt)
  1744  		s.callResult(n.Call.(*ir.CallExpr), callGo)
  1745  
  1746  	case ir.OAS2DOTTYPE:
  1747  		n := n.(*ir.AssignListStmt)
  1748  		var res, resok *ssa.Value
  1749  		if n.Rhs[0].Op() == ir.ODOTTYPE2 {
  1750  			res, resok = s.dottype(n.Rhs[0].(*ir.TypeAssertExpr), true)
  1751  		} else {
  1752  			res, resok = s.dynamicDottype(n.Rhs[0].(*ir.DynamicTypeAssertExpr), true)
  1753  		}
  1754  		deref := false
  1755  		if !ssa.CanSSA(n.Rhs[0].Type()) {
  1756  			if res.Op != ssa.OpLoad {
  1757  				s.Fatalf("dottype of non-load")
  1758  			}
  1759  			mem := s.mem()
  1760  			if res.Args[1] != mem {
  1761  				s.Fatalf("memory no longer live from 2-result dottype load")
  1762  			}
  1763  			deref = true
  1764  			res = res.Args[0]
  1765  		}
  1766  		s.assign(n.Lhs[0], res, deref, 0)
  1767  		s.assign(n.Lhs[1], resok, false, 0)
  1768  		return
  1769  
  1770  	case ir.OAS2FUNC:
  1771  		// We come here only when it is an intrinsic call returning two values.
  1772  		n := n.(*ir.AssignListStmt)
  1773  		call := n.Rhs[0].(*ir.CallExpr)
  1774  		if !ir.IsIntrinsicCall(call) {
  1775  			s.Fatalf("non-intrinsic AS2FUNC not expanded %v", call)
  1776  		}
  1777  		v := s.intrinsicCall(call)
  1778  		v1 := s.newValue1(ssa.OpSelect0, n.Lhs[0].Type(), v)
  1779  		v2 := s.newValue1(ssa.OpSelect1, n.Lhs[1].Type(), v)
  1780  		s.assign(n.Lhs[0], v1, false, 0)
  1781  		s.assign(n.Lhs[1], v2, false, 0)
  1782  		return
  1783  
  1784  	case ir.ODCL:
  1785  		n := n.(*ir.Decl)
  1786  		if v := n.X; v.Esc() == ir.EscHeap {
  1787  			s.newHeapaddr(v)
  1788  		}
  1789  
  1790  	case ir.OLABEL:
  1791  		n := n.(*ir.LabelStmt)
  1792  		sym := n.Label
  1793  		if sym.IsBlank() {
  1794  			// Nothing to do because the label isn't targetable. See issue 52278.
  1795  			break
  1796  		}
  1797  		lab := s.label(sym)
  1798  
  1799  		// The label might already have a target block via a goto.
  1800  		if lab.target == nil {
  1801  			lab.target = s.f.NewBlock(block.BlockPlain)
  1802  		}
  1803  
  1804  		// Go to that label.
  1805  		// (We pretend "label:" is preceded by "goto label", unless the predecessor is unreachable.)
  1806  		if s.curBlock != nil {
  1807  			b := s.endBlock()
  1808  			b.AddEdgeTo(lab.target)
  1809  		}
  1810  		s.startBlock(lab.target)
  1811  
  1812  	case ir.OGOTO:
  1813  		n := n.(*ir.BranchStmt)
  1814  		sym := n.Label
  1815  
  1816  		lab := s.label(sym)
  1817  		if lab.target == nil {
  1818  			lab.target = s.f.NewBlock(block.BlockPlain)
  1819  		}
  1820  
  1821  		b := s.endBlock()
  1822  		b.Pos = s.lastPos.WithIsStmt() // Do this even if b is an empty block.
  1823  		b.AddEdgeTo(lab.target)
  1824  
  1825  	case ir.OAS:
  1826  		n := n.(*ir.AssignStmt)
  1827  		if n.X == n.Y && n.X.Op() == ir.ONAME {
  1828  			// An x=x assignment. No point in doing anything
  1829  			// here. In addition, skipping this assignment
  1830  			// prevents generating:
  1831  			//   VARDEF x
  1832  			//   COPY x -> x
  1833  			// which is bad because x is incorrectly considered
  1834  			// dead before the vardef. See issue #14904.
  1835  			return
  1836  		}
  1837  
  1838  		// mayOverlap keeps track of whether the LHS and RHS might
  1839  		// refer to partially overlapping memory. Partial overlapping can
  1840  		// only happen for arrays, see the comment in moveWhichMayOverlap.
  1841  		//
  1842  		// If both sides of the assignment are not dereferences, then partial
  1843  		// overlap can't happen. Partial overlap can only occur only when the
  1844  		// arrays referenced are strictly smaller parts of the same base array.
  1845  		// If one side of the assignment is a full array, then partial overlap
  1846  		// can't happen. (The arrays are either disjoint or identical.)
  1847  		ny := peelConvNop(n.Y)
  1848  		mayOverlap := n.X.Op() == ir.ODEREF && (n.Y != nil && ny.Op() == ir.ODEREF)
  1849  		if ny != nil && ny.Op() == ir.ODEREF {
  1850  			p := peelConvNop(ny.(*ir.StarExpr).X)
  1851  			if p.Op() == ir.OSPTR && p.(*ir.UnaryExpr).X.Type().IsString() {
  1852  				// Pointer fields of strings point to unmodifiable memory.
  1853  				// That memory can't overlap with the memory being written.
  1854  				mayOverlap = false
  1855  			}
  1856  		}
  1857  
  1858  		// Evaluate RHS.
  1859  		rhs := n.Y
  1860  		if rhs != nil {
  1861  			switch rhs.Op() {
  1862  			case ir.OSTRUCTLIT, ir.OARRAYLIT, ir.OSLICELIT:
  1863  				// All literals with nonzero fields have already been
  1864  				// rewritten during walk. Any that remain are just T{}
  1865  				// or equivalents. Use the zero value.
  1866  				if !ir.IsZero(rhs) {
  1867  					s.Fatalf("literal with nonzero value in SSA: %v", rhs)
  1868  				}
  1869  				rhs = nil
  1870  			case ir.OAPPEND:
  1871  				rhs := rhs.(*ir.CallExpr)
  1872  				// Check whether we're writing the result of an append back to the same slice.
  1873  				// If so, we handle it specially to avoid write barriers on the fast
  1874  				// (non-growth) path.
  1875  				if !ir.SameSafeExpr(n.X, rhs.Args[0]) || base.Flag.N != 0 {
  1876  					break
  1877  				}
  1878  				// If the slice can be SSA'd, it'll be on the stack,
  1879  				// so there will be no write barriers,
  1880  				// so there's no need to attempt to prevent them.
  1881  				if s.canSSA(n.X) {
  1882  					if base.Debug.Append > 0 { // replicating old diagnostic message
  1883  						base.WarnfAt(n.Pos(), "append: len-only update (in local slice)")
  1884  					}
  1885  					break
  1886  				}
  1887  				if base.Debug.Append > 0 {
  1888  					base.WarnfAt(n.Pos(), "append: len-only update")
  1889  				}
  1890  				s.append(rhs, true)
  1891  				return
  1892  			}
  1893  		}
  1894  
  1895  		if ir.IsBlank(n.X) {
  1896  			// _ = rhs
  1897  			// Just evaluate rhs for side-effects.
  1898  			if rhs != nil {
  1899  				s.expr(rhs)
  1900  			}
  1901  			return
  1902  		}
  1903  
  1904  		var t *types.Type
  1905  		if n.Y != nil {
  1906  			t = n.Y.Type()
  1907  		} else {
  1908  			t = n.X.Type()
  1909  		}
  1910  
  1911  		var r *ssa.Value
  1912  		deref := !ssa.CanSSA(t)
  1913  		if deref {
  1914  			if rhs == nil {
  1915  				r = nil // Signal assign to use OpZero.
  1916  			} else {
  1917  				r = s.addr(rhs)
  1918  			}
  1919  		} else {
  1920  			if rhs == nil {
  1921  				r = s.zeroVal(t)
  1922  			} else {
  1923  				r = s.expr(rhs)
  1924  			}
  1925  		}
  1926  
  1927  		var skip skipMask
  1928  		if rhs != nil && (rhs.Op() == ir.OSLICE || rhs.Op() == ir.OSLICE3 || rhs.Op() == ir.OSLICESTR) && ir.SameSafeExpr(rhs.(*ir.SliceExpr).X, n.X) {
  1929  			// We're assigning a slicing operation back to its source.
  1930  			// Don't write back fields we aren't changing. See issue #14855.
  1931  			rhs := rhs.(*ir.SliceExpr)
  1932  			i, j, k := rhs.Low, rhs.High, rhs.Max
  1933  			if i != nil && (i.Op() == ir.OLITERAL && i.Val().Kind() == constant.Int && ir.Int64Val(i) == 0) {
  1934  				// [0:...] is the same as [:...]
  1935  				i = nil
  1936  			}
  1937  			// TODO: detect defaults for len/cap also.
  1938  			// Currently doesn't really work because (*p)[:len(*p)] appears here as:
  1939  			//    tmp = len(*p)
  1940  			//    (*p)[:tmp]
  1941  			// if j != nil && (j.Op == OLEN && SameSafeExpr(j.Left, n.Left)) {
  1942  			//      j = nil
  1943  			// }
  1944  			// if k != nil && (k.Op == OCAP && SameSafeExpr(k.Left, n.Left)) {
  1945  			//      k = nil
  1946  			// }
  1947  			if i == nil {
  1948  				skip |= skipPtr
  1949  				if j == nil {
  1950  					skip |= skipLen
  1951  				}
  1952  				if k == nil {
  1953  					skip |= skipCap
  1954  				}
  1955  			}
  1956  		}
  1957  
  1958  		s.assignWhichMayOverlap(n.X, r, deref, skip, mayOverlap)
  1959  
  1960  	case ir.OIF:
  1961  		n := n.(*ir.IfStmt)
  1962  		if ir.IsConst(n.Cond, constant.Bool) {
  1963  			s.stmtList(n.Cond.Init())
  1964  			if ir.BoolVal(n.Cond) {
  1965  				s.stmtList(n.Body)
  1966  			} else {
  1967  				s.stmtList(n.Else)
  1968  			}
  1969  			break
  1970  		}
  1971  
  1972  		bEnd := s.f.NewBlock(block.BlockPlain)
  1973  		var likely int8
  1974  		if n.Likely {
  1975  			likely = 1
  1976  		}
  1977  		var bThen *ssa.Block
  1978  		if len(n.Body) != 0 {
  1979  			bThen = s.f.NewBlock(block.BlockPlain)
  1980  		} else {
  1981  			bThen = bEnd
  1982  		}
  1983  		var bElse *ssa.Block
  1984  		if len(n.Else) != 0 {
  1985  			bElse = s.f.NewBlock(block.BlockPlain)
  1986  		} else {
  1987  			bElse = bEnd
  1988  		}
  1989  		s.condBranch(n.Cond, bThen, bElse, likely)
  1990  
  1991  		if len(n.Body) != 0 {
  1992  			s.startBlock(bThen)
  1993  			s.stmtList(n.Body)
  1994  			if b := s.endBlock(); b != nil {
  1995  				b.AddEdgeTo(bEnd)
  1996  			}
  1997  		}
  1998  		if len(n.Else) != 0 {
  1999  			s.startBlock(bElse)
  2000  			s.stmtList(n.Else)
  2001  			if b := s.endBlock(); b != nil {
  2002  				b.AddEdgeTo(bEnd)
  2003  			}
  2004  		}
  2005  		s.startBlock(bEnd)
  2006  
  2007  	case ir.ORETURN:
  2008  		n := n.(*ir.ReturnStmt)
  2009  		s.stmtList(n.Results)
  2010  		b := s.exit()
  2011  		b.Pos = s.lastPos.WithIsStmt()
  2012  
  2013  	case ir.OTAILCALL:
  2014  		n := n.(*ir.TailCallStmt)
  2015  		s.callResult(n.Call, callTail)
  2016  		call := s.mem()
  2017  		b := s.endBlock()
  2018  		b.Kind = block.BlockRetJmp // could use BlockExit. BlockRetJmp is mostly for clarity.
  2019  		b.SetControl(call)
  2020  
  2021  	case ir.OCONTINUE, ir.OBREAK:
  2022  		n := n.(*ir.BranchStmt)
  2023  		var to *ssa.Block
  2024  		if n.Label == nil {
  2025  			// plain break/continue
  2026  			switch n.Op() {
  2027  			case ir.OCONTINUE:
  2028  				to = s.continueTo
  2029  			case ir.OBREAK:
  2030  				to = s.breakTo
  2031  			}
  2032  		} else {
  2033  			// labeled break/continue; look up the target
  2034  			sym := n.Label
  2035  			lab := s.label(sym)
  2036  			switch n.Op() {
  2037  			case ir.OCONTINUE:
  2038  				to = lab.continueTarget
  2039  			case ir.OBREAK:
  2040  				to = lab.breakTarget
  2041  			}
  2042  		}
  2043  
  2044  		b := s.endBlock()
  2045  		b.Pos = s.lastPos.WithIsStmt() // Do this even if b is an empty block.
  2046  		b.AddEdgeTo(to)
  2047  
  2048  	case ir.OFOR:
  2049  		// OFOR: for Ninit; Left; Right { Nbody }
  2050  		// cond (Left); body (Nbody); incr (Right)
  2051  		n := n.(*ir.ForStmt)
  2052  		base.Assert(!n.DistinctVars) // Should all be rewritten before escape analysis
  2053  		bCond := s.f.NewBlock(block.BlockPlain)
  2054  		bBody := s.f.NewBlock(block.BlockPlain)
  2055  		bIncr := s.f.NewBlock(block.BlockPlain)
  2056  		bEnd := s.f.NewBlock(block.BlockPlain)
  2057  
  2058  		// ensure empty for loops have correct position; issue #30167
  2059  		bBody.Pos = n.Pos()
  2060  
  2061  		// first, jump to condition test
  2062  		b := s.endBlock()
  2063  		b.AddEdgeTo(bCond)
  2064  
  2065  		// generate code to test condition
  2066  		s.startBlock(bCond)
  2067  		if n.Cond != nil {
  2068  			s.condBranch(n.Cond, bBody, bEnd, 1)
  2069  		} else {
  2070  			b := s.endBlock()
  2071  			b.Kind = block.BlockPlain
  2072  			b.AddEdgeTo(bBody)
  2073  		}
  2074  
  2075  		// set up for continue/break in body
  2076  		prevContinue := s.continueTo
  2077  		prevBreak := s.breakTo
  2078  		s.continueTo = bIncr
  2079  		s.breakTo = bEnd
  2080  		var lab *ssaLabel
  2081  		if sym := n.Label; sym != nil {
  2082  			// labeled for loop
  2083  			lab = s.label(sym)
  2084  			lab.continueTarget = bIncr
  2085  			lab.breakTarget = bEnd
  2086  		}
  2087  
  2088  		// generate body
  2089  		s.startBlock(bBody)
  2090  		s.stmtList(n.Body)
  2091  
  2092  		// tear down continue/break
  2093  		s.continueTo = prevContinue
  2094  		s.breakTo = prevBreak
  2095  		if lab != nil {
  2096  			lab.continueTarget = nil
  2097  			lab.breakTarget = nil
  2098  		}
  2099  
  2100  		// done with body, goto incr
  2101  		if b := s.endBlock(); b != nil {
  2102  			b.AddEdgeTo(bIncr)
  2103  		}
  2104  
  2105  		// generate incr
  2106  		s.startBlock(bIncr)
  2107  		if n.Post != nil {
  2108  			s.stmt(n.Post)
  2109  		}
  2110  		if b := s.endBlock(); b != nil {
  2111  			b.AddEdgeTo(bCond)
  2112  			// It can happen that bIncr ends in a block containing only VARKILL,
  2113  			// and that muddles the debugging experience.
  2114  			if b.Pos == src.NoXPos {
  2115  				b.Pos = bCond.Pos
  2116  			}
  2117  		}
  2118  
  2119  		s.startBlock(bEnd)
  2120  
  2121  	case ir.OSWITCH, ir.OSELECT:
  2122  		// These have been mostly rewritten by the front end into their Nbody fields.
  2123  		// Our main task is to correctly hook up any break statements.
  2124  		bEnd := s.f.NewBlock(block.BlockPlain)
  2125  
  2126  		prevBreak := s.breakTo
  2127  		s.breakTo = bEnd
  2128  		var sym *types.Sym
  2129  		var body ir.Nodes
  2130  		if n.Op() == ir.OSWITCH {
  2131  			n := n.(*ir.SwitchStmt)
  2132  			sym = n.Label
  2133  			body = n.Compiled
  2134  		} else {
  2135  			n := n.(*ir.SelectStmt)
  2136  			sym = n.Label
  2137  			body = n.Compiled
  2138  		}
  2139  
  2140  		var lab *ssaLabel
  2141  		if sym != nil {
  2142  			// labeled
  2143  			lab = s.label(sym)
  2144  			lab.breakTarget = bEnd
  2145  		}
  2146  
  2147  		// generate body code
  2148  		s.stmtList(body)
  2149  
  2150  		s.breakTo = prevBreak
  2151  		if lab != nil {
  2152  			lab.breakTarget = nil
  2153  		}
  2154  
  2155  		// walk adds explicit OBREAK nodes to the end of all reachable code paths.
  2156  		// If we still have a current block here, then mark it unreachable.
  2157  		if s.curBlock != nil {
  2158  			m := s.mem()
  2159  			b := s.endBlock()
  2160  			b.Kind = block.BlockExit
  2161  			b.SetControl(m)
  2162  		}
  2163  		s.startBlock(bEnd)
  2164  
  2165  	case ir.OJUMPTABLE:
  2166  		n := n.(*ir.JumpTableStmt)
  2167  
  2168  		// Make blocks we'll need.
  2169  		jt := s.f.NewBlock(block.BlockJumpTable)
  2170  		bEnd := s.f.NewBlock(block.BlockPlain)
  2171  
  2172  		// The only thing that needs evaluating is the index we're looking up.
  2173  		idx := s.expr(n.Idx)
  2174  		unsigned := idx.Type.IsUnsigned()
  2175  
  2176  		// Extend so we can do everything in uintptr arithmetic.
  2177  		t := types.Types[types.TUINTPTR]
  2178  		idx = s.conv(nil, idx, idx.Type, t)
  2179  
  2180  		// The ending condition for the current block decides whether we'll use
  2181  		// the jump table at all.
  2182  		// We check that min <= idx <= max and jump around the jump table
  2183  		// if that test fails.
  2184  		// We implement min <= idx <= max with 0 <= idx-min <= max-min, because
  2185  		// we'll need idx-min anyway as the control value for the jump table.
  2186  		var min, max uint64
  2187  		if unsigned {
  2188  			min, _ = constant.Uint64Val(n.Cases[0])
  2189  			max, _ = constant.Uint64Val(n.Cases[len(n.Cases)-1])
  2190  		} else {
  2191  			mn, _ := constant.Int64Val(n.Cases[0])
  2192  			mx, _ := constant.Int64Val(n.Cases[len(n.Cases)-1])
  2193  			min = uint64(mn)
  2194  			max = uint64(mx)
  2195  		}
  2196  		// Compare idx-min with max-min, to see if we can use the jump table.
  2197  		idx = s.newValue2(s.ssaOp(ir.OSUB, t), t, idx, s.uintptrConstant(min))
  2198  		width := s.uintptrConstant(max - min)
  2199  		cmp := s.newValue2(s.ssaOp(ir.OLE, t), types.Types[types.TBOOL], idx, width)
  2200  		b := s.endBlock()
  2201  		b.Kind = block.BlockIf
  2202  		b.SetControl(cmp)
  2203  		b.AddEdgeTo(jt)             // in range - use jump table
  2204  		b.AddEdgeTo(bEnd)           // out of range - no case in the jump table will trigger
  2205  		b.Likely = ssa.BranchLikely // TODO: assumes missing the table entirely is unlikely. True?
  2206  
  2207  		// Build jump table block.
  2208  		s.startBlock(jt)
  2209  		jt.Pos = n.Pos()
  2210  		if base.Flag.Cfg.SpectreIndex {
  2211  			idx = s.newValue2(ssa.OpSpectreSliceIndex, t, idx, width)
  2212  		}
  2213  		jt.SetControl(idx)
  2214  
  2215  		// Figure out where we should go for each index in the table.
  2216  		table := make([]*ssa.Block, max-min+1)
  2217  		for i := range table {
  2218  			table[i] = bEnd // default target
  2219  		}
  2220  		for i := range n.Targets {
  2221  			c := n.Cases[i]
  2222  			lab := s.label(n.Targets[i])
  2223  			if lab.target == nil {
  2224  				lab.target = s.f.NewBlock(block.BlockPlain)
  2225  			}
  2226  			var val uint64
  2227  			if unsigned {
  2228  				val, _ = constant.Uint64Val(c)
  2229  			} else {
  2230  				vl, _ := constant.Int64Val(c)
  2231  				val = uint64(vl)
  2232  			}
  2233  			// Overwrite the default target.
  2234  			table[val-min] = lab.target
  2235  		}
  2236  		for _, t := range table {
  2237  			jt.AddEdgeTo(t)
  2238  		}
  2239  		s.endBlock()
  2240  
  2241  		s.startBlock(bEnd)
  2242  
  2243  	case ir.OINTERFACESWITCH:
  2244  		n := n.(*ir.InterfaceSwitchStmt)
  2245  		typs := s.f.Config.Types
  2246  
  2247  		t := s.expr(n.RuntimeType)
  2248  		h := s.expr(n.Hash)
  2249  		d := s.newValue1A(ssa.OpAddr, typs.BytePtr, n.Descriptor, s.sb)
  2250  
  2251  		// Check the cache first.
  2252  		var merge *ssa.Block
  2253  		if base.Flag.N == 0 && rtabi.UseInterfaceSwitchCache(Arch.LinkArch.Family) {
  2254  			// Note: we can only use the cache if we have the right atomic load instruction.
  2255  			// Double-check that here.
  2256  			if intrinsics.lookup(Arch.LinkArch.Arch, "internal/runtime/atomic", "Loadp") == nil {
  2257  				s.Fatalf("atomic load not available")
  2258  			}
  2259  			merge = s.f.NewBlock(block.BlockPlain)
  2260  			cacheHit := s.f.NewBlock(block.BlockPlain)
  2261  			cacheMiss := s.f.NewBlock(block.BlockPlain)
  2262  			loopHead := s.f.NewBlock(block.BlockPlain)
  2263  			loopBody := s.f.NewBlock(block.BlockPlain)
  2264  
  2265  			// Pick right size ops.
  2266  			var mul, and, add, zext ssa.Op
  2267  			if s.config.PtrSize == 4 {
  2268  				mul = ssa.OpMul32
  2269  				and = ssa.OpAnd32
  2270  				add = ssa.OpAdd32
  2271  				zext = ssa.OpCopy
  2272  			} else {
  2273  				mul = ssa.OpMul64
  2274  				and = ssa.OpAnd64
  2275  				add = ssa.OpAdd64
  2276  				zext = ssa.OpZeroExt32to64
  2277  			}
  2278  
  2279  			// Load cache pointer out of descriptor, with an atomic load so
  2280  			// we ensure that we see a fully written cache.
  2281  			atomicLoad := s.newValue2(ssa.OpAtomicLoadPtr, types.NewTuple(typs.BytePtr, types.TypeMem), d, s.mem())
  2282  			cache := s.newValue1(ssa.OpSelect0, typs.BytePtr, atomicLoad)
  2283  			s.vars[memVar] = s.newValue1(ssa.OpSelect1, types.TypeMem, atomicLoad)
  2284  
  2285  			// Initialize hash variable.
  2286  			s.vars[hashVar] = s.newValue1(zext, typs.Uintptr, h)
  2287  
  2288  			// Load mask from cache.
  2289  			mask := s.newValue2(ssa.OpLoad, typs.Uintptr, cache, s.mem())
  2290  			// Jump to loop head.
  2291  			b := s.endBlock()
  2292  			b.AddEdgeTo(loopHead)
  2293  
  2294  			// At loop head, get pointer to the cache entry.
  2295  			//   e := &cache.Entries[hash&mask]
  2296  			s.startBlock(loopHead)
  2297  			entries := s.newValue2(ssa.OpAddPtr, typs.UintptrPtr, cache, s.uintptrConstant(uint64(s.config.PtrSize)))
  2298  			idx := s.newValue2(and, typs.Uintptr, s.variable(hashVar, typs.Uintptr), mask)
  2299  			idx = s.newValue2(mul, typs.Uintptr, idx, s.uintptrConstant(uint64(3*s.config.PtrSize)))
  2300  			e := s.newValue2(ssa.OpAddPtr, typs.UintptrPtr, entries, idx)
  2301  			//   hash++
  2302  			s.vars[hashVar] = s.newValue2(add, typs.Uintptr, s.variable(hashVar, typs.Uintptr), s.uintptrConstant(1))
  2303  
  2304  			// Look for a cache hit.
  2305  			//   if e.Typ == t { goto hit }
  2306  			eTyp := s.newValue2(ssa.OpLoad, typs.Uintptr, e, s.mem())
  2307  			cmp1 := s.newValue2(ssa.OpEqPtr, typs.Bool, t, eTyp)
  2308  			b = s.endBlock()
  2309  			b.Kind = block.BlockIf
  2310  			b.SetControl(cmp1)
  2311  			b.AddEdgeTo(cacheHit)
  2312  			b.AddEdgeTo(loopBody)
  2313  
  2314  			// Look for an empty entry, the tombstone for this hash table.
  2315  			//   if e.Typ == nil { goto miss }
  2316  			s.startBlock(loopBody)
  2317  			cmp2 := s.newValue2(ssa.OpEqPtr, typs.Bool, eTyp, s.constNil(typs.BytePtr))
  2318  			b = s.endBlock()
  2319  			b.Kind = block.BlockIf
  2320  			b.SetControl(cmp2)
  2321  			b.AddEdgeTo(cacheMiss)
  2322  			b.AddEdgeTo(loopHead)
  2323  
  2324  			// On a hit, load the data fields of the cache entry.
  2325  			//   Case = e.Case
  2326  			//   Itab = e.Itab
  2327  			s.startBlock(cacheHit)
  2328  			eCase := s.newValue2(ssa.OpLoad, typs.Int, s.newValue1I(ssa.OpOffPtr, typs.IntPtr, s.config.PtrSize, e), s.mem())
  2329  			eItab := s.newValue2(ssa.OpLoad, typs.BytePtr, s.newValue1I(ssa.OpOffPtr, typs.BytePtrPtr, 2*s.config.PtrSize, e), s.mem())
  2330  			s.assign(n.Case, eCase, false, 0)
  2331  			s.assign(n.Itab, eItab, false, 0)
  2332  			b = s.endBlock()
  2333  			b.AddEdgeTo(merge)
  2334  
  2335  			// On a miss, call into the runtime to get the answer.
  2336  			s.startBlock(cacheMiss)
  2337  		}
  2338  
  2339  		r := s.rtcall(ir.Syms.InterfaceSwitch, true, []*types.Type{typs.Int, typs.BytePtr}, d, t)
  2340  		s.assign(n.Case, r[0], false, 0)
  2341  		s.assign(n.Itab, r[1], false, 0)
  2342  
  2343  		if merge != nil {
  2344  			// Cache hits merge in here.
  2345  			b := s.endBlock()
  2346  			b.Kind = block.BlockPlain
  2347  			b.AddEdgeTo(merge)
  2348  			s.startBlock(merge)
  2349  		}
  2350  
  2351  	case ir.OCHECKNIL:
  2352  		n := n.(*ir.UnaryExpr)
  2353  		p := s.expr(n.X)
  2354  		_ = s.nilCheck(p)
  2355  		// TODO: check that throwing away the nilcheck result is ok.
  2356  
  2357  	case ir.OINLMARK:
  2358  		n := n.(*ir.InlineMarkStmt)
  2359  		s.newValue1I(ssa.OpInlMark, types.TypeVoid, n.Index, s.mem())
  2360  
  2361  	default:
  2362  		s.Fatalf("unhandled stmt %v", n.Op())
  2363  	}
  2364  }
  2365  
  2366  // If true, share as many open-coded defer exits as possible (with the downside of
  2367  // worse line-number information)
  2368  const shareDeferExits = false
  2369  
  2370  // exit processes any code that needs to be generated just before returning.
  2371  // It returns a BlockRet block that ends the control flow. Its control value
  2372  // will be set to the final memory state.
  2373  func (s *state) exit() *ssa.Block {
  2374  	if s.hasdefer {
  2375  		if s.hasOpenDefers {
  2376  			if shareDeferExits && s.lastDeferExit != nil && len(s.openDefers) == s.lastDeferCount {
  2377  				if s.curBlock.Kind != block.BlockPlain {
  2378  					panic("Block for an exit should be BlockPlain")
  2379  				}
  2380  				s.curBlock.AddEdgeTo(s.lastDeferExit)
  2381  				s.endBlock()
  2382  				return s.lastDeferFinalBlock
  2383  			}
  2384  			s.openDeferExit()
  2385  		} else {
  2386  			// Shared deferreturn is assigned the "last" position in the function.
  2387  			// The linker picks the first deferreturn call it sees, so this is
  2388  			// the only sensible "shared" place.
  2389  			// To not-share deferreturn, the protocol would need to be changed
  2390  			// so that the call to deferproc-etc would receive the PC offset from
  2391  			// the return PC, and the runtime would need to use that instead of
  2392  			// the deferreturn retrieved from the pcln information.
  2393  			// opendefers would remain a problem, however.
  2394  			s.pushLine(s.curfn.Endlineno)
  2395  			s.rtcall(ir.Syms.Deferreturn, true, nil)
  2396  			s.popLine()
  2397  		}
  2398  	}
  2399  
  2400  	// Do actual return.
  2401  	// These currently turn into self-copies (in many cases).
  2402  	resultFields := s.curfn.Type().Results()
  2403  	results := make([]*ssa.Value, len(resultFields)+1, len(resultFields)+1)
  2404  	// Store SSAable and heap-escaped PPARAMOUT variables back to stack locations.
  2405  	for i, f := range resultFields {
  2406  		n := f.Nname.(*ir.Name)
  2407  		if s.canSSA(n) { // result is in some SSA variable
  2408  			if !n.IsOutputParamInRegisters() && n.Type().HasPointers() {
  2409  				// We are about to store to the result slot.
  2410  				s.vars[memVar] = s.newValue1A(ssa.OpVarDef, types.TypeMem, n, s.mem())
  2411  			}
  2412  			results[i] = s.variable(n, n.Type())
  2413  		} else if !n.OnStack() { // result is actually heap allocated
  2414  			// We are about to copy the in-heap result to the result slot.
  2415  			if n.Type().HasPointers() {
  2416  				s.vars[memVar] = s.newValue1A(ssa.OpVarDef, types.TypeMem, n, s.mem())
  2417  			}
  2418  			ha := s.expr(n.Heapaddr)
  2419  			s.instrumentFields(n.Type(), ha, instrumentRead)
  2420  			results[i] = s.newValue2(ssa.OpDereference, n.Type(), ha, s.mem())
  2421  		} else { // result is not SSA-able; not escaped, so not on heap, but too large for SSA.
  2422  			// Before register ABI this ought to be a self-move, home=dest,
  2423  			// With register ABI, it's still a self-move if parameter is on stack (i.e., too big or overflowed)
  2424  			// No VarDef, as the result slot is already holding live value.
  2425  			results[i] = s.newValue2(ssa.OpDereference, n.Type(), s.addr(n), s.mem())
  2426  		}
  2427  	}
  2428  
  2429  	// In -race mode, we need to call racefuncexit.
  2430  	// Note: This has to happen after we load any heap-allocated results,
  2431  	// otherwise races will be attributed to the caller instead.
  2432  	if s.instrumentEnterExit {
  2433  		s.rtcall(ir.Syms.Racefuncexit, true, nil)
  2434  	}
  2435  
  2436  	results[len(results)-1] = s.mem()
  2437  	m := s.newValue0(ssa.OpMakeResult, s.f.OwnAux.LateExpansionResultType())
  2438  	m.AddArgs(results...)
  2439  
  2440  	b := s.endBlock()
  2441  	b.Kind = block.BlockRet
  2442  	b.SetControl(m)
  2443  	if s.hasdefer && s.hasOpenDefers {
  2444  		s.lastDeferFinalBlock = b
  2445  	}
  2446  	return b
  2447  }
  2448  
  2449  type opAndType struct {
  2450  	op    ir.Op
  2451  	etype types.Kind
  2452  }
  2453  
  2454  var opToSSA = map[opAndType]ssa.Op{
  2455  	{ir.OADD, types.TINT8}:    ssa.OpAdd8,
  2456  	{ir.OADD, types.TUINT8}:   ssa.OpAdd8,
  2457  	{ir.OADD, types.TINT16}:   ssa.OpAdd16,
  2458  	{ir.OADD, types.TUINT16}:  ssa.OpAdd16,
  2459  	{ir.OADD, types.TINT32}:   ssa.OpAdd32,
  2460  	{ir.OADD, types.TUINT32}:  ssa.OpAdd32,
  2461  	{ir.OADD, types.TINT64}:   ssa.OpAdd64,
  2462  	{ir.OADD, types.TUINT64}:  ssa.OpAdd64,
  2463  	{ir.OADD, types.TFLOAT32}: ssa.OpAdd32F,
  2464  	{ir.OADD, types.TFLOAT64}: ssa.OpAdd64F,
  2465  
  2466  	{ir.OSUB, types.TINT8}:    ssa.OpSub8,
  2467  	{ir.OSUB, types.TUINT8}:   ssa.OpSub8,
  2468  	{ir.OSUB, types.TINT16}:   ssa.OpSub16,
  2469  	{ir.OSUB, types.TUINT16}:  ssa.OpSub16,
  2470  	{ir.OSUB, types.TINT32}:   ssa.OpSub32,
  2471  	{ir.OSUB, types.TUINT32}:  ssa.OpSub32,
  2472  	{ir.OSUB, types.TINT64}:   ssa.OpSub64,
  2473  	{ir.OSUB, types.TUINT64}:  ssa.OpSub64,
  2474  	{ir.OSUB, types.TFLOAT32}: ssa.OpSub32F,
  2475  	{ir.OSUB, types.TFLOAT64}: ssa.OpSub64F,
  2476  
  2477  	{ir.ONOT, types.TBOOL}: ssa.OpNot,
  2478  
  2479  	{ir.ONEG, types.TINT8}:    ssa.OpNeg8,
  2480  	{ir.ONEG, types.TUINT8}:   ssa.OpNeg8,
  2481  	{ir.ONEG, types.TINT16}:   ssa.OpNeg16,
  2482  	{ir.ONEG, types.TUINT16}:  ssa.OpNeg16,
  2483  	{ir.ONEG, types.TINT32}:   ssa.OpNeg32,
  2484  	{ir.ONEG, types.TUINT32}:  ssa.OpNeg32,
  2485  	{ir.ONEG, types.TINT64}:   ssa.OpNeg64,
  2486  	{ir.ONEG, types.TUINT64}:  ssa.OpNeg64,
  2487  	{ir.ONEG, types.TFLOAT32}: ssa.OpNeg32F,
  2488  	{ir.ONEG, types.TFLOAT64}: ssa.OpNeg64F,
  2489  
  2490  	{ir.OBITNOT, types.TINT8}:   ssa.OpCom8,
  2491  	{ir.OBITNOT, types.TUINT8}:  ssa.OpCom8,
  2492  	{ir.OBITNOT, types.TINT16}:  ssa.OpCom16,
  2493  	{ir.OBITNOT, types.TUINT16}: ssa.OpCom16,
  2494  	{ir.OBITNOT, types.TINT32}:  ssa.OpCom32,
  2495  	{ir.OBITNOT, types.TUINT32}: ssa.OpCom32,
  2496  	{ir.OBITNOT, types.TINT64}:  ssa.OpCom64,
  2497  	{ir.OBITNOT, types.TUINT64}: ssa.OpCom64,
  2498  
  2499  	{ir.OIMAG, types.TCOMPLEX64}:  ssa.OpComplexImag,
  2500  	{ir.OIMAG, types.TCOMPLEX128}: ssa.OpComplexImag,
  2501  	{ir.OREAL, types.TCOMPLEX64}:  ssa.OpComplexReal,
  2502  	{ir.OREAL, types.TCOMPLEX128}: ssa.OpComplexReal,
  2503  
  2504  	{ir.OMUL, types.TINT8}:    ssa.OpMul8,
  2505  	{ir.OMUL, types.TUINT8}:   ssa.OpMul8,
  2506  	{ir.OMUL, types.TINT16}:   ssa.OpMul16,
  2507  	{ir.OMUL, types.TUINT16}:  ssa.OpMul16,
  2508  	{ir.OMUL, types.TINT32}:   ssa.OpMul32,
  2509  	{ir.OMUL, types.TUINT32}:  ssa.OpMul32,
  2510  	{ir.OMUL, types.TINT64}:   ssa.OpMul64,
  2511  	{ir.OMUL, types.TUINT64}:  ssa.OpMul64,
  2512  	{ir.OMUL, types.TFLOAT32}: ssa.OpMul32F,
  2513  	{ir.OMUL, types.TFLOAT64}: ssa.OpMul64F,
  2514  
  2515  	{ir.ODIV, types.TFLOAT32}: ssa.OpDiv32F,
  2516  	{ir.ODIV, types.TFLOAT64}: ssa.OpDiv64F,
  2517  
  2518  	{ir.ODIV, types.TINT8}:   ssa.OpDiv8,
  2519  	{ir.ODIV, types.TUINT8}:  ssa.OpDiv8u,
  2520  	{ir.ODIV, types.TINT16}:  ssa.OpDiv16,
  2521  	{ir.ODIV, types.TUINT16}: ssa.OpDiv16u,
  2522  	{ir.ODIV, types.TINT32}:  ssa.OpDiv32,
  2523  	{ir.ODIV, types.TUINT32}: ssa.OpDiv32u,
  2524  	{ir.ODIV, types.TINT64}:  ssa.OpDiv64,
  2525  	{ir.ODIV, types.TUINT64}: ssa.OpDiv64u,
  2526  
  2527  	{ir.OMOD, types.TINT8}:   ssa.OpMod8,
  2528  	{ir.OMOD, types.TUINT8}:  ssa.OpMod8u,
  2529  	{ir.OMOD, types.TINT16}:  ssa.OpMod16,
  2530  	{ir.OMOD, types.TUINT16}: ssa.OpMod16u,
  2531  	{ir.OMOD, types.TINT32}:  ssa.OpMod32,
  2532  	{ir.OMOD, types.TUINT32}: ssa.OpMod32u,
  2533  	{ir.OMOD, types.TINT64}:  ssa.OpMod64,
  2534  	{ir.OMOD, types.TUINT64}: ssa.OpMod64u,
  2535  
  2536  	{ir.OAND, types.TINT8}:   ssa.OpAnd8,
  2537  	{ir.OAND, types.TUINT8}:  ssa.OpAnd8,
  2538  	{ir.OAND, types.TINT16}:  ssa.OpAnd16,
  2539  	{ir.OAND, types.TUINT16}: ssa.OpAnd16,
  2540  	{ir.OAND, types.TINT32}:  ssa.OpAnd32,
  2541  	{ir.OAND, types.TUINT32}: ssa.OpAnd32,
  2542  	{ir.OAND, types.TINT64}:  ssa.OpAnd64,
  2543  	{ir.OAND, types.TUINT64}: ssa.OpAnd64,
  2544  
  2545  	{ir.OOR, types.TINT8}:   ssa.OpOr8,
  2546  	{ir.OOR, types.TUINT8}:  ssa.OpOr8,
  2547  	{ir.OOR, types.TINT16}:  ssa.OpOr16,
  2548  	{ir.OOR, types.TUINT16}: ssa.OpOr16,
  2549  	{ir.OOR, types.TINT32}:  ssa.OpOr32,
  2550  	{ir.OOR, types.TUINT32}: ssa.OpOr32,
  2551  	{ir.OOR, types.TINT64}:  ssa.OpOr64,
  2552  	{ir.OOR, types.TUINT64}: ssa.OpOr64,
  2553  
  2554  	{ir.OXOR, types.TINT8}:   ssa.OpXor8,
  2555  	{ir.OXOR, types.TUINT8}:  ssa.OpXor8,
  2556  	{ir.OXOR, types.TINT16}:  ssa.OpXor16,
  2557  	{ir.OXOR, types.TUINT16}: ssa.OpXor16,
  2558  	{ir.OXOR, types.TINT32}:  ssa.OpXor32,
  2559  	{ir.OXOR, types.TUINT32}: ssa.OpXor32,
  2560  	{ir.OXOR, types.TINT64}:  ssa.OpXor64,
  2561  	{ir.OXOR, types.TUINT64}: ssa.OpXor64,
  2562  
  2563  	{ir.OEQ, types.TBOOL}:      ssa.OpEqB,
  2564  	{ir.OEQ, types.TINT8}:      ssa.OpEq8,
  2565  	{ir.OEQ, types.TUINT8}:     ssa.OpEq8,
  2566  	{ir.OEQ, types.TINT16}:     ssa.OpEq16,
  2567  	{ir.OEQ, types.TUINT16}:    ssa.OpEq16,
  2568  	{ir.OEQ, types.TINT32}:     ssa.OpEq32,
  2569  	{ir.OEQ, types.TUINT32}:    ssa.OpEq32,
  2570  	{ir.OEQ, types.TINT64}:     ssa.OpEq64,
  2571  	{ir.OEQ, types.TUINT64}:    ssa.OpEq64,
  2572  	{ir.OEQ, types.TINTER}:     ssa.OpEqInter,
  2573  	{ir.OEQ, types.TSLICE}:     ssa.OpEqSlice,
  2574  	{ir.OEQ, types.TFUNC}:      ssa.OpEqPtr,
  2575  	{ir.OEQ, types.TMAP}:       ssa.OpEqPtr,
  2576  	{ir.OEQ, types.TCHAN}:      ssa.OpEqPtr,
  2577  	{ir.OEQ, types.TPTR}:       ssa.OpEqPtr,
  2578  	{ir.OEQ, types.TUINTPTR}:   ssa.OpEqPtr,
  2579  	{ir.OEQ, types.TUNSAFEPTR}: ssa.OpEqPtr,
  2580  	{ir.OEQ, types.TFLOAT64}:   ssa.OpEq64F,
  2581  	{ir.OEQ, types.TFLOAT32}:   ssa.OpEq32F,
  2582  
  2583  	{ir.ONE, types.TBOOL}:      ssa.OpNeqB,
  2584  	{ir.ONE, types.TINT8}:      ssa.OpNeq8,
  2585  	{ir.ONE, types.TUINT8}:     ssa.OpNeq8,
  2586  	{ir.ONE, types.TINT16}:     ssa.OpNeq16,
  2587  	{ir.ONE, types.TUINT16}:    ssa.OpNeq16,
  2588  	{ir.ONE, types.TINT32}:     ssa.OpNeq32,
  2589  	{ir.ONE, types.TUINT32}:    ssa.OpNeq32,
  2590  	{ir.ONE, types.TINT64}:     ssa.OpNeq64,
  2591  	{ir.ONE, types.TUINT64}:    ssa.OpNeq64,
  2592  	{ir.ONE, types.TINTER}:     ssa.OpNeqInter,
  2593  	{ir.ONE, types.TSLICE}:     ssa.OpNeqSlice,
  2594  	{ir.ONE, types.TFUNC}:      ssa.OpNeqPtr,
  2595  	{ir.ONE, types.TMAP}:       ssa.OpNeqPtr,
  2596  	{ir.ONE, types.TCHAN}:      ssa.OpNeqPtr,
  2597  	{ir.ONE, types.TPTR}:       ssa.OpNeqPtr,
  2598  	{ir.ONE, types.TUINTPTR}:   ssa.OpNeqPtr,
  2599  	{ir.ONE, types.TUNSAFEPTR}: ssa.OpNeqPtr,
  2600  	{ir.ONE, types.TFLOAT64}:   ssa.OpNeq64F,
  2601  	{ir.ONE, types.TFLOAT32}:   ssa.OpNeq32F,
  2602  
  2603  	{ir.OLT, types.TINT8}:    ssa.OpLess8,
  2604  	{ir.OLT, types.TUINT8}:   ssa.OpLess8U,
  2605  	{ir.OLT, types.TINT16}:   ssa.OpLess16,
  2606  	{ir.OLT, types.TUINT16}:  ssa.OpLess16U,
  2607  	{ir.OLT, types.TINT32}:   ssa.OpLess32,
  2608  	{ir.OLT, types.TUINT32}:  ssa.OpLess32U,
  2609  	{ir.OLT, types.TINT64}:   ssa.OpLess64,
  2610  	{ir.OLT, types.TUINT64}:  ssa.OpLess64U,
  2611  	{ir.OLT, types.TFLOAT64}: ssa.OpLess64F,
  2612  	{ir.OLT, types.TFLOAT32}: ssa.OpLess32F,
  2613  
  2614  	{ir.OLE, types.TINT8}:    ssa.OpLeq8,
  2615  	{ir.OLE, types.TUINT8}:   ssa.OpLeq8U,
  2616  	{ir.OLE, types.TINT16}:   ssa.OpLeq16,
  2617  	{ir.OLE, types.TUINT16}:  ssa.OpLeq16U,
  2618  	{ir.OLE, types.TINT32}:   ssa.OpLeq32,
  2619  	{ir.OLE, types.TUINT32}:  ssa.OpLeq32U,
  2620  	{ir.OLE, types.TINT64}:   ssa.OpLeq64,
  2621  	{ir.OLE, types.TUINT64}:  ssa.OpLeq64U,
  2622  	{ir.OLE, types.TFLOAT64}: ssa.OpLeq64F,
  2623  	{ir.OLE, types.TFLOAT32}: ssa.OpLeq32F,
  2624  }
  2625  
  2626  func (s *state) concreteEtype(t *types.Type) types.Kind {
  2627  	e := t.Kind()
  2628  	switch e {
  2629  	default:
  2630  		return e
  2631  	case types.TINT:
  2632  		if s.config.PtrSize == 8 {
  2633  			return types.TINT64
  2634  		}
  2635  		return types.TINT32
  2636  	case types.TUINT:
  2637  		if s.config.PtrSize == 8 {
  2638  			return types.TUINT64
  2639  		}
  2640  		return types.TUINT32
  2641  	case types.TUINTPTR:
  2642  		if s.config.PtrSize == 8 {
  2643  			return types.TUINT64
  2644  		}
  2645  		return types.TUINT32
  2646  	}
  2647  }
  2648  
  2649  func (s *state) ssaOp(op ir.Op, t *types.Type) ssa.Op {
  2650  	etype := s.concreteEtype(t)
  2651  	x, ok := opToSSA[opAndType{op, etype}]
  2652  	if !ok {
  2653  		s.Fatalf("unhandled binary op %v %s", op, etype)
  2654  	}
  2655  	return x
  2656  }
  2657  
  2658  type opAndTwoTypes struct {
  2659  	op     ir.Op
  2660  	etype1 types.Kind
  2661  	etype2 types.Kind
  2662  }
  2663  
  2664  type twoTypes struct {
  2665  	etype1 types.Kind
  2666  	etype2 types.Kind
  2667  }
  2668  
  2669  type twoOpsAndType struct {
  2670  	op1              ssa.Op
  2671  	op2              ssa.Op
  2672  	intermediateType types.Kind
  2673  }
  2674  
  2675  var fpConvOpToSSA = map[twoTypes]twoOpsAndType{
  2676  
  2677  	{types.TINT8, types.TFLOAT32}:  {ssa.OpSignExt8to32, ssa.OpCvt32to32F, types.TINT32},
  2678  	{types.TINT16, types.TFLOAT32}: {ssa.OpSignExt16to32, ssa.OpCvt32to32F, types.TINT32},
  2679  	{types.TINT32, types.TFLOAT32}: {ssa.OpCopy, ssa.OpCvt32to32F, types.TINT32},
  2680  	{types.TINT64, types.TFLOAT32}: {ssa.OpCopy, ssa.OpCvt64to32F, types.TINT64},
  2681  
  2682  	{types.TINT8, types.TFLOAT64}:  {ssa.OpSignExt8to32, ssa.OpCvt32to64F, types.TINT32},
  2683  	{types.TINT16, types.TFLOAT64}: {ssa.OpSignExt16to32, ssa.OpCvt32to64F, types.TINT32},
  2684  	{types.TINT32, types.TFLOAT64}: {ssa.OpCopy, ssa.OpCvt32to64F, types.TINT32},
  2685  	{types.TINT64, types.TFLOAT64}: {ssa.OpCopy, ssa.OpCvt64to64F, types.TINT64},
  2686  
  2687  	{types.TFLOAT32, types.TINT8}:  {ssa.OpCvt32Fto32, ssa.OpTrunc32to8, types.TINT32},
  2688  	{types.TFLOAT32, types.TINT16}: {ssa.OpCvt32Fto32, ssa.OpTrunc32to16, types.TINT32},
  2689  	{types.TFLOAT32, types.TINT32}: {ssa.OpCvt32Fto32, ssa.OpCopy, types.TINT32},
  2690  	{types.TFLOAT32, types.TINT64}: {ssa.OpCvt32Fto64, ssa.OpCopy, types.TINT64},
  2691  
  2692  	{types.TFLOAT64, types.TINT8}:  {ssa.OpCvt64Fto32, ssa.OpTrunc32to8, types.TINT32},
  2693  	{types.TFLOAT64, types.TINT16}: {ssa.OpCvt64Fto32, ssa.OpTrunc32to16, types.TINT32},
  2694  	{types.TFLOAT64, types.TINT32}: {ssa.OpCvt64Fto32, ssa.OpCopy, types.TINT32},
  2695  	{types.TFLOAT64, types.TINT64}: {ssa.OpCvt64Fto64, ssa.OpCopy, types.TINT64},
  2696  	// unsigned
  2697  	{types.TUINT8, types.TFLOAT32}:  {ssa.OpZeroExt8to32, ssa.OpCvt32to32F, types.TINT32},
  2698  	{types.TUINT16, types.TFLOAT32}: {ssa.OpZeroExt16to32, ssa.OpCvt32to32F, types.TINT32},
  2699  	{types.TUINT32, types.TFLOAT32}: {ssa.OpZeroExt32to64, ssa.OpCvt64to32F, types.TINT64}, // go wide to dodge unsigned
  2700  	{types.TUINT64, types.TFLOAT32}: {ssa.OpCopy, ssa.OpInvalid, types.TUINT64},            // Cvt64Uto32F, branchy code expansion instead
  2701  
  2702  	{types.TUINT8, types.TFLOAT64}:  {ssa.OpZeroExt8to32, ssa.OpCvt32to64F, types.TINT32},
  2703  	{types.TUINT16, types.TFLOAT64}: {ssa.OpZeroExt16to32, ssa.OpCvt32to64F, types.TINT32},
  2704  	{types.TUINT32, types.TFLOAT64}: {ssa.OpZeroExt32to64, ssa.OpCvt64to64F, types.TINT64}, // go wide to dodge unsigned
  2705  	{types.TUINT64, types.TFLOAT64}: {ssa.OpCopy, ssa.OpInvalid, types.TUINT64},            // Cvt64Uto64F, branchy code expansion instead
  2706  
  2707  	{types.TFLOAT32, types.TUINT8}:  {ssa.OpCvt32Fto32, ssa.OpTrunc32to8, types.TINT32},
  2708  	{types.TFLOAT32, types.TUINT16}: {ssa.OpCvt32Fto32, ssa.OpTrunc32to16, types.TINT32},
  2709  	{types.TFLOAT32, types.TUINT32}: {ssa.OpInvalid, ssa.OpCopy, types.TINT64},  // Cvt64Fto32U, branchy code expansion instead
  2710  	{types.TFLOAT32, types.TUINT64}: {ssa.OpInvalid, ssa.OpCopy, types.TUINT64}, // Cvt32Fto64U, branchy code expansion instead
  2711  
  2712  	{types.TFLOAT64, types.TUINT8}:  {ssa.OpCvt64Fto32, ssa.OpTrunc32to8, types.TINT32},
  2713  	{types.TFLOAT64, types.TUINT16}: {ssa.OpCvt64Fto32, ssa.OpTrunc32to16, types.TINT32},
  2714  	{types.TFLOAT64, types.TUINT32}: {ssa.OpInvalid, ssa.OpCopy, types.TINT64},  // Cvt64Fto32U, branchy code expansion instead
  2715  	{types.TFLOAT64, types.TUINT64}: {ssa.OpInvalid, ssa.OpCopy, types.TUINT64}, // Cvt64Fto64U, branchy code expansion instead
  2716  
  2717  	// float
  2718  	{types.TFLOAT64, types.TFLOAT32}: {ssa.OpCvt64Fto32F, ssa.OpCopy, types.TFLOAT32},
  2719  	{types.TFLOAT64, types.TFLOAT64}: {ssa.OpRound64F, ssa.OpCopy, types.TFLOAT64},
  2720  	{types.TFLOAT32, types.TFLOAT32}: {ssa.OpRound32F, ssa.OpCopy, types.TFLOAT32},
  2721  	{types.TFLOAT32, types.TFLOAT64}: {ssa.OpCvt32Fto64F, ssa.OpCopy, types.TFLOAT64},
  2722  }
  2723  
  2724  // this map is used only for 32-bit arch, and only includes the difference
  2725  // on 32-bit arch, don't use int64<->float conversion for uint32
  2726  var fpConvOpToSSA32 = map[twoTypes]twoOpsAndType{
  2727  	{types.TUINT32, types.TFLOAT32}: {ssa.OpCopy, ssa.OpCvt32Uto32F, types.TUINT32},
  2728  	{types.TUINT32, types.TFLOAT64}: {ssa.OpCopy, ssa.OpCvt32Uto64F, types.TUINT32},
  2729  	{types.TFLOAT32, types.TUINT32}: {ssa.OpCvt32Fto32U, ssa.OpCopy, types.TUINT32},
  2730  	{types.TFLOAT64, types.TUINT32}: {ssa.OpCvt64Fto32U, ssa.OpCopy, types.TUINT32},
  2731  }
  2732  
  2733  // uint64<->float conversions, only on machines that have instructions for that
  2734  var uint64fpConvOpToSSA = map[twoTypes]twoOpsAndType{
  2735  	{types.TUINT64, types.TFLOAT32}: {ssa.OpCopy, ssa.OpCvt64Uto32F, types.TUINT64},
  2736  	{types.TUINT64, types.TFLOAT64}: {ssa.OpCopy, ssa.OpCvt64Uto64F, types.TUINT64},
  2737  	{types.TFLOAT32, types.TUINT64}: {ssa.OpCvt32Fto64U, ssa.OpCopy, types.TUINT64},
  2738  	{types.TFLOAT64, types.TUINT64}: {ssa.OpCvt64Fto64U, ssa.OpCopy, types.TUINT64},
  2739  }
  2740  
  2741  var shiftOpToSSA = map[opAndTwoTypes]ssa.Op{
  2742  	{ir.OLSH, types.TINT8, types.TUINT8}:   ssa.OpLsh8x8,
  2743  	{ir.OLSH, types.TUINT8, types.TUINT8}:  ssa.OpLsh8x8,
  2744  	{ir.OLSH, types.TINT8, types.TUINT16}:  ssa.OpLsh8x16,
  2745  	{ir.OLSH, types.TUINT8, types.TUINT16}: ssa.OpLsh8x16,
  2746  	{ir.OLSH, types.TINT8, types.TUINT32}:  ssa.OpLsh8x32,
  2747  	{ir.OLSH, types.TUINT8, types.TUINT32}: ssa.OpLsh8x32,
  2748  	{ir.OLSH, types.TINT8, types.TUINT64}:  ssa.OpLsh8x64,
  2749  	{ir.OLSH, types.TUINT8, types.TUINT64}: ssa.OpLsh8x64,
  2750  
  2751  	{ir.OLSH, types.TINT16, types.TUINT8}:   ssa.OpLsh16x8,
  2752  	{ir.OLSH, types.TUINT16, types.TUINT8}:  ssa.OpLsh16x8,
  2753  	{ir.OLSH, types.TINT16, types.TUINT16}:  ssa.OpLsh16x16,
  2754  	{ir.OLSH, types.TUINT16, types.TUINT16}: ssa.OpLsh16x16,
  2755  	{ir.OLSH, types.TINT16, types.TUINT32}:  ssa.OpLsh16x32,
  2756  	{ir.OLSH, types.TUINT16, types.TUINT32}: ssa.OpLsh16x32,
  2757  	{ir.OLSH, types.TINT16, types.TUINT64}:  ssa.OpLsh16x64,
  2758  	{ir.OLSH, types.TUINT16, types.TUINT64}: ssa.OpLsh16x64,
  2759  
  2760  	{ir.OLSH, types.TINT32, types.TUINT8}:   ssa.OpLsh32x8,
  2761  	{ir.OLSH, types.TUINT32, types.TUINT8}:  ssa.OpLsh32x8,
  2762  	{ir.OLSH, types.TINT32, types.TUINT16}:  ssa.OpLsh32x16,
  2763  	{ir.OLSH, types.TUINT32, types.TUINT16}: ssa.OpLsh32x16,
  2764  	{ir.OLSH, types.TINT32, types.TUINT32}:  ssa.OpLsh32x32,
  2765  	{ir.OLSH, types.TUINT32, types.TUINT32}: ssa.OpLsh32x32,
  2766  	{ir.OLSH, types.TINT32, types.TUINT64}:  ssa.OpLsh32x64,
  2767  	{ir.OLSH, types.TUINT32, types.TUINT64}: ssa.OpLsh32x64,
  2768  
  2769  	{ir.OLSH, types.TINT64, types.TUINT8}:   ssa.OpLsh64x8,
  2770  	{ir.OLSH, types.TUINT64, types.TUINT8}:  ssa.OpLsh64x8,
  2771  	{ir.OLSH, types.TINT64, types.TUINT16}:  ssa.OpLsh64x16,
  2772  	{ir.OLSH, types.TUINT64, types.TUINT16}: ssa.OpLsh64x16,
  2773  	{ir.OLSH, types.TINT64, types.TUINT32}:  ssa.OpLsh64x32,
  2774  	{ir.OLSH, types.TUINT64, types.TUINT32}: ssa.OpLsh64x32,
  2775  	{ir.OLSH, types.TINT64, types.TUINT64}:  ssa.OpLsh64x64,
  2776  	{ir.OLSH, types.TUINT64, types.TUINT64}: ssa.OpLsh64x64,
  2777  
  2778  	{ir.ORSH, types.TINT8, types.TUINT8}:   ssa.OpRsh8x8,
  2779  	{ir.ORSH, types.TUINT8, types.TUINT8}:  ssa.OpRsh8Ux8,
  2780  	{ir.ORSH, types.TINT8, types.TUINT16}:  ssa.OpRsh8x16,
  2781  	{ir.ORSH, types.TUINT8, types.TUINT16}: ssa.OpRsh8Ux16,
  2782  	{ir.ORSH, types.TINT8, types.TUINT32}:  ssa.OpRsh8x32,
  2783  	{ir.ORSH, types.TUINT8, types.TUINT32}: ssa.OpRsh8Ux32,
  2784  	{ir.ORSH, types.TINT8, types.TUINT64}:  ssa.OpRsh8x64,
  2785  	{ir.ORSH, types.TUINT8, types.TUINT64}: ssa.OpRsh8Ux64,
  2786  
  2787  	{ir.ORSH, types.TINT16, types.TUINT8}:   ssa.OpRsh16x8,
  2788  	{ir.ORSH, types.TUINT16, types.TUINT8}:  ssa.OpRsh16Ux8,
  2789  	{ir.ORSH, types.TINT16, types.TUINT16}:  ssa.OpRsh16x16,
  2790  	{ir.ORSH, types.TUINT16, types.TUINT16}: ssa.OpRsh16Ux16,
  2791  	{ir.ORSH, types.TINT16, types.TUINT32}:  ssa.OpRsh16x32,
  2792  	{ir.ORSH, types.TUINT16, types.TUINT32}: ssa.OpRsh16Ux32,
  2793  	{ir.ORSH, types.TINT16, types.TUINT64}:  ssa.OpRsh16x64,
  2794  	{ir.ORSH, types.TUINT16, types.TUINT64}: ssa.OpRsh16Ux64,
  2795  
  2796  	{ir.ORSH, types.TINT32, types.TUINT8}:   ssa.OpRsh32x8,
  2797  	{ir.ORSH, types.TUINT32, types.TUINT8}:  ssa.OpRsh32Ux8,
  2798  	{ir.ORSH, types.TINT32, types.TUINT16}:  ssa.OpRsh32x16,
  2799  	{ir.ORSH, types.TUINT32, types.TUINT16}: ssa.OpRsh32Ux16,
  2800  	{ir.ORSH, types.TINT32, types.TUINT32}:  ssa.OpRsh32x32,
  2801  	{ir.ORSH, types.TUINT32, types.TUINT32}: ssa.OpRsh32Ux32,
  2802  	{ir.ORSH, types.TINT32, types.TUINT64}:  ssa.OpRsh32x64,
  2803  	{ir.ORSH, types.TUINT32, types.TUINT64}: ssa.OpRsh32Ux64,
  2804  
  2805  	{ir.ORSH, types.TINT64, types.TUINT8}:   ssa.OpRsh64x8,
  2806  	{ir.ORSH, types.TUINT64, types.TUINT8}:  ssa.OpRsh64Ux8,
  2807  	{ir.ORSH, types.TINT64, types.TUINT16}:  ssa.OpRsh64x16,
  2808  	{ir.ORSH, types.TUINT64, types.TUINT16}: ssa.OpRsh64Ux16,
  2809  	{ir.ORSH, types.TINT64, types.TUINT32}:  ssa.OpRsh64x32,
  2810  	{ir.ORSH, types.TUINT64, types.TUINT32}: ssa.OpRsh64Ux32,
  2811  	{ir.ORSH, types.TINT64, types.TUINT64}:  ssa.OpRsh64x64,
  2812  	{ir.ORSH, types.TUINT64, types.TUINT64}: ssa.OpRsh64Ux64,
  2813  }
  2814  
  2815  func (s *state) ssaShiftOp(op ir.Op, t *types.Type, u *types.Type) ssa.Op {
  2816  	etype1 := s.concreteEtype(t)
  2817  	etype2 := s.concreteEtype(u)
  2818  	x, ok := shiftOpToSSA[opAndTwoTypes{op, etype1, etype2}]
  2819  	if !ok {
  2820  		s.Fatalf("unhandled shift op %v etype=%s/%s", op, etype1, etype2)
  2821  	}
  2822  	return x
  2823  }
  2824  
  2825  func (s *state) uintptrConstant(v uint64) *ssa.Value {
  2826  	if s.config.PtrSize == 4 {
  2827  		return s.newValue0I(ssa.OpConst32, types.Types[types.TUINTPTR], int64(v))
  2828  	}
  2829  	return s.newValue0I(ssa.OpConst64, types.Types[types.TUINTPTR], int64(v))
  2830  }
  2831  
  2832  func (s *state) conv(n ir.Node, v *ssa.Value, ft, tt *types.Type) *ssa.Value {
  2833  	if ft.IsBoolean() && tt.IsKind(types.TUINT8) {
  2834  		// Bool -> uint8 is generated internally when indexing into runtime.staticbyte.
  2835  		return s.newValue1(ssa.OpCvtBoolToUint8, tt, v)
  2836  	}
  2837  	if ft.IsInteger() && tt.IsInteger() {
  2838  		var op ssa.Op
  2839  		if tt.Size() == ft.Size() {
  2840  			op = ssa.OpCopy
  2841  		} else if tt.Size() < ft.Size() {
  2842  			// truncation
  2843  			switch 10*ft.Size() + tt.Size() {
  2844  			case 21:
  2845  				op = ssa.OpTrunc16to8
  2846  			case 41:
  2847  				op = ssa.OpTrunc32to8
  2848  			case 42:
  2849  				op = ssa.OpTrunc32to16
  2850  			case 81:
  2851  				op = ssa.OpTrunc64to8
  2852  			case 82:
  2853  				op = ssa.OpTrunc64to16
  2854  			case 84:
  2855  				op = ssa.OpTrunc64to32
  2856  			default:
  2857  				s.Fatalf("weird integer truncation %v -> %v", ft, tt)
  2858  			}
  2859  		} else if ft.IsSigned() {
  2860  			// sign extension
  2861  			switch 10*ft.Size() + tt.Size() {
  2862  			case 12:
  2863  				op = ssa.OpSignExt8to16
  2864  			case 14:
  2865  				op = ssa.OpSignExt8to32
  2866  			case 18:
  2867  				op = ssa.OpSignExt8to64
  2868  			case 24:
  2869  				op = ssa.OpSignExt16to32
  2870  			case 28:
  2871  				op = ssa.OpSignExt16to64
  2872  			case 48:
  2873  				op = ssa.OpSignExt32to64
  2874  			default:
  2875  				s.Fatalf("bad integer sign extension %v -> %v", ft, tt)
  2876  			}
  2877  		} else {
  2878  			// zero extension
  2879  			switch 10*ft.Size() + tt.Size() {
  2880  			case 12:
  2881  				op = ssa.OpZeroExt8to16
  2882  			case 14:
  2883  				op = ssa.OpZeroExt8to32
  2884  			case 18:
  2885  				op = ssa.OpZeroExt8to64
  2886  			case 24:
  2887  				op = ssa.OpZeroExt16to32
  2888  			case 28:
  2889  				op = ssa.OpZeroExt16to64
  2890  			case 48:
  2891  				op = ssa.OpZeroExt32to64
  2892  			default:
  2893  				s.Fatalf("weird integer sign extension %v -> %v", ft, tt)
  2894  			}
  2895  		}
  2896  		return s.newValue1(op, tt, v)
  2897  	}
  2898  
  2899  	if ft.IsComplex() && tt.IsComplex() {
  2900  		var op ssa.Op
  2901  		if ft.Size() == tt.Size() {
  2902  			switch ft.Size() {
  2903  			case 8:
  2904  				op = ssa.OpRound32F
  2905  			case 16:
  2906  				op = ssa.OpRound64F
  2907  			default:
  2908  				s.Fatalf("weird complex conversion %v -> %v", ft, tt)
  2909  			}
  2910  		} else if ft.Size() == 8 && tt.Size() == 16 {
  2911  			op = ssa.OpCvt32Fto64F
  2912  		} else if ft.Size() == 16 && tt.Size() == 8 {
  2913  			op = ssa.OpCvt64Fto32F
  2914  		} else {
  2915  			s.Fatalf("weird complex conversion %v -> %v", ft, tt)
  2916  		}
  2917  		ftp := types.FloatForComplex(ft)
  2918  		ttp := types.FloatForComplex(tt)
  2919  		return s.newValue2(ssa.OpComplexMake, tt,
  2920  			s.newValueOrSfCall1(op, ttp, s.newValue1(ssa.OpComplexReal, ftp, v)),
  2921  			s.newValueOrSfCall1(op, ttp, s.newValue1(ssa.OpComplexImag, ftp, v)))
  2922  	}
  2923  
  2924  	if tt.IsComplex() { // and ft is not complex
  2925  		// Needed for generics support - can't happen in normal Go code.
  2926  		et := types.FloatForComplex(tt)
  2927  		v = s.conv(n, v, ft, et)
  2928  		return s.newValue2(ssa.OpComplexMake, tt, v, s.zeroVal(et))
  2929  	}
  2930  
  2931  	if ft.IsFloat() || tt.IsFloat() {
  2932  		cft, ctt := s.concreteEtype(ft), s.concreteEtype(tt)
  2933  		conv, ok := fpConvOpToSSA[twoTypes{cft, ctt}]
  2934  		// there's a change to a conversion-op table, this restores the old behavior if ConvertHash is false.
  2935  		// use salted hash to distinguish unsigned convert at a Pos from signed convert at a Pos
  2936  		if ctt == types.TUINT32 && ft.IsFloat() && !base.ConvertHash.MatchPosWithInfo(n.Pos(), "U", nil) {
  2937  			// revert to old behavior
  2938  			conv.op1 = ssa.OpCvt64Fto64
  2939  			if cft == types.TFLOAT32 {
  2940  				conv.op1 = ssa.OpCvt32Fto64
  2941  			}
  2942  			conv.op2 = ssa.OpTrunc64to32
  2943  
  2944  		}
  2945  		if s.config.RegSize == 4 && Arch.LinkArch.Family != sys.MIPS && !s.softFloat {
  2946  			if conv1, ok1 := fpConvOpToSSA32[twoTypes{s.concreteEtype(ft), s.concreteEtype(tt)}]; ok1 {
  2947  				conv = conv1
  2948  			}
  2949  		}
  2950  		if Arch.LinkArch.Family == sys.ARM64 || Arch.LinkArch.Family == sys.Wasm || Arch.LinkArch.Family == sys.S390X || s.softFloat {
  2951  			if conv1, ok1 := uint64fpConvOpToSSA[twoTypes{s.concreteEtype(ft), s.concreteEtype(tt)}]; ok1 {
  2952  				conv = conv1
  2953  			}
  2954  		}
  2955  
  2956  		if Arch.LinkArch.Family == sys.MIPS && !s.softFloat {
  2957  			if ft.Size() == 4 && ft.IsInteger() && !ft.IsSigned() {
  2958  				// tt is float32 or float64, and ft is also unsigned
  2959  				if tt.Size() == 4 {
  2960  					return s.uint32Tofloat32(n, v, ft, tt)
  2961  				}
  2962  				if tt.Size() == 8 {
  2963  					return s.uint32Tofloat64(n, v, ft, tt)
  2964  				}
  2965  			} else if tt.Size() == 4 && tt.IsInteger() && !tt.IsSigned() {
  2966  				// ft is float32 or float64, and tt is unsigned integer
  2967  				if ft.Size() == 4 {
  2968  					return s.float32ToUint32(n, v, ft, tt)
  2969  				}
  2970  				if ft.Size() == 8 {
  2971  					return s.float64ToUint32(n, v, ft, tt)
  2972  				}
  2973  			}
  2974  		}
  2975  
  2976  		if !ok {
  2977  			s.Fatalf("weird float conversion %v -> %v", ft, tt)
  2978  		}
  2979  		op1, op2, it := conv.op1, conv.op2, conv.intermediateType
  2980  
  2981  		if op1 != ssa.OpInvalid && op2 != ssa.OpInvalid {
  2982  			// normal case, not tripping over unsigned 64
  2983  			if op1 == ssa.OpCopy {
  2984  				if op2 == ssa.OpCopy {
  2985  					return v
  2986  				}
  2987  				return s.newValueOrSfCall1(op2, tt, v)
  2988  			}
  2989  			if op2 == ssa.OpCopy {
  2990  				return s.newValueOrSfCall1(op1, tt, v)
  2991  			}
  2992  			return s.newValueOrSfCall1(op2, tt, s.newValueOrSfCall1(op1, types.Types[it], v))
  2993  		}
  2994  		// Tricky 64-bit unsigned cases.
  2995  		if ft.IsInteger() {
  2996  			// tt is float32 or float64, and ft is also unsigned
  2997  			if tt.Size() == 4 {
  2998  				return s.uint64Tofloat32(n, v, ft, tt)
  2999  			}
  3000  			if tt.Size() == 8 {
  3001  				return s.uint64Tofloat64(n, v, ft, tt)
  3002  			}
  3003  			s.Fatalf("weird unsigned integer to float conversion %v -> %v", ft, tt)
  3004  		}
  3005  		// ft is float32 or float64, and tt is unsigned integer
  3006  		if ft.Size() == 4 {
  3007  			switch tt.Size() {
  3008  			case 8:
  3009  				return s.float32ToUint64(n, v, ft, tt)
  3010  			case 4, 2, 1:
  3011  				// TODO should 2 and 1 saturate or truncate?
  3012  				return s.float32ToUint32(n, v, ft, tt)
  3013  			}
  3014  		}
  3015  		if ft.Size() == 8 {
  3016  			switch tt.Size() {
  3017  			case 8:
  3018  				return s.float64ToUint64(n, v, ft, tt)
  3019  			case 4, 2, 1:
  3020  				// TODO should 2 and 1 saturate or truncate?
  3021  				return s.float64ToUint32(n, v, ft, tt)
  3022  			}
  3023  
  3024  		}
  3025  		s.Fatalf("weird float to unsigned integer conversion %v -> %v", ft, tt)
  3026  		return nil
  3027  	}
  3028  
  3029  	s.Fatalf("unhandled OCONV %s -> %s", ft.Kind(), tt.Kind())
  3030  	return nil
  3031  }
  3032  
  3033  // expr converts the expression n to ssa, adds it to s and returns the ssa result.
  3034  func (s *state) expr(n ir.Node) *ssa.Value {
  3035  	return s.exprCheckPtr(n, true)
  3036  }
  3037  
  3038  func (s *state) exprCheckPtr(n ir.Node, checkPtrOK bool) *ssa.Value {
  3039  	if ir.HasUniquePos(n) {
  3040  		// ONAMEs and named OLITERALs have the line number
  3041  		// of the decl, not the use. See issue 14742.
  3042  		s.pushLine(n.Pos())
  3043  		defer s.popLine()
  3044  	}
  3045  
  3046  	s.stmtList(n.Init())
  3047  	switch n.Op() {
  3048  	case ir.OBYTES2STRTMP:
  3049  		n := n.(*ir.ConvExpr)
  3050  		slice := s.expr(n.X)
  3051  		ptr := s.newValue1(ssa.OpSlicePtr, s.f.Config.Types.BytePtr, slice)
  3052  		len := s.newValue1(ssa.OpSliceLen, types.Types[types.TINT], slice)
  3053  		return s.newValue2(ssa.OpStringMake, n.Type(), ptr, len)
  3054  	case ir.OSTR2BYTESTMP:
  3055  		n := n.(*ir.ConvExpr)
  3056  		str := s.expr(n.X)
  3057  		ptr := s.newValue1(ssa.OpStringPtr, s.f.Config.Types.BytePtr, str)
  3058  		if !n.NonNil() {
  3059  			// We need to ensure []byte("") evaluates to []byte{}, and not []byte(nil).
  3060  			//
  3061  			// TODO(mdempsky): Investigate using "len != 0" instead of "ptr != nil".
  3062  			cond := s.newValue2(ssa.OpNeqPtr, types.Types[types.TBOOL], ptr, s.constNil(ptr.Type))
  3063  			zerobase := s.newValue1A(ssa.OpAddr, ptr.Type, ir.Syms.Zerobase, s.sb)
  3064  			ptr = s.ternary(cond, ptr, zerobase)
  3065  		}
  3066  		len := s.newValue1(ssa.OpStringLen, types.Types[types.TINT], str)
  3067  		return s.newValue3(ssa.OpSliceMake, n.Type(), ptr, len, len)
  3068  	case ir.OCFUNC:
  3069  		n := n.(*ir.UnaryExpr)
  3070  		aux := n.X.(*ir.Name).Linksym()
  3071  		// OCFUNC is used to build function values, which must
  3072  		// always reference ABIInternal entry points.
  3073  		if aux.ABI() != obj.ABIInternal {
  3074  			s.Fatalf("expected ABIInternal: %v", aux.ABI())
  3075  		}
  3076  		return s.entryNewValue1A(ssa.OpAddr, n.Type(), aux, s.sb)
  3077  	case ir.ONAME:
  3078  		n := n.(*ir.Name)
  3079  		if n.Class == ir.PFUNC {
  3080  			// "value" of a function is the address of the function's closure
  3081  			sym := staticdata.FuncLinksym(n)
  3082  			return s.entryNewValue1A(ssa.OpAddr, types.NewPtr(n.Type()), sym, s.sb)
  3083  		}
  3084  		if s.canSSA(n) {
  3085  			return s.variable(n, n.Type())
  3086  		}
  3087  		return s.load(n.Type(), s.addr(n))
  3088  	case ir.OLINKSYMOFFSET:
  3089  		n := n.(*ir.LinksymOffsetExpr)
  3090  		return s.load(n.Type(), s.addr(n))
  3091  	case ir.ONIL:
  3092  		n := n.(*ir.NilExpr)
  3093  		t := n.Type()
  3094  		switch {
  3095  		case t.IsSlice():
  3096  			return s.constSlice(t)
  3097  		case t.IsInterface():
  3098  			return s.constInterface(t)
  3099  		default:
  3100  			return s.constNil(t)
  3101  		}
  3102  	case ir.OLITERAL:
  3103  		switch u := n.Val(); u.Kind() {
  3104  		case constant.Int:
  3105  			i := ir.IntVal(n.Type(), u)
  3106  			switch n.Type().Size() {
  3107  			case 1:
  3108  				return s.constInt8(n.Type(), int8(i))
  3109  			case 2:
  3110  				return s.constInt16(n.Type(), int16(i))
  3111  			case 4:
  3112  				return s.constInt32(n.Type(), int32(i))
  3113  			case 8:
  3114  				return s.constInt64(n.Type(), i)
  3115  			default:
  3116  				s.Fatalf("bad integer size %d", n.Type().Size())
  3117  				return nil
  3118  			}
  3119  		case constant.String:
  3120  			i := constant.StringVal(u)
  3121  			if i == "" {
  3122  				return s.constEmptyString(n.Type())
  3123  			}
  3124  			return s.entryNewValue0A(ssa.OpConstString, n.Type(), ssa.StringToAux(i))
  3125  		case constant.Bool:
  3126  			return s.constBool(constant.BoolVal(u))
  3127  		case constant.Float:
  3128  			f, _ := constant.Float64Val(u)
  3129  			switch n.Type().Size() {
  3130  			case 4:
  3131  				return s.constFloat32(n.Type(), f)
  3132  			case 8:
  3133  				return s.constFloat64(n.Type(), f)
  3134  			default:
  3135  				s.Fatalf("bad float size %d", n.Type().Size())
  3136  				return nil
  3137  			}
  3138  		case constant.Complex:
  3139  			re, _ := constant.Float64Val(constant.Real(u))
  3140  			im, _ := constant.Float64Val(constant.Imag(u))
  3141  			switch n.Type().Size() {
  3142  			case 8:
  3143  				pt := types.Types[types.TFLOAT32]
  3144  				return s.newValue2(ssa.OpComplexMake, n.Type(),
  3145  					s.constFloat32(pt, re),
  3146  					s.constFloat32(pt, im))
  3147  			case 16:
  3148  				pt := types.Types[types.TFLOAT64]
  3149  				return s.newValue2(ssa.OpComplexMake, n.Type(),
  3150  					s.constFloat64(pt, re),
  3151  					s.constFloat64(pt, im))
  3152  			default:
  3153  				s.Fatalf("bad complex size %d", n.Type().Size())
  3154  				return nil
  3155  			}
  3156  		default:
  3157  			s.Fatalf("unhandled OLITERAL %v", u.Kind())
  3158  			return nil
  3159  		}
  3160  	case ir.OCONVNOP:
  3161  		n := n.(*ir.ConvExpr)
  3162  		to := n.Type()
  3163  		from := n.X.Type()
  3164  
  3165  		// Assume everything will work out, so set up our return value.
  3166  		// Anything interesting that happens from here is a fatal.
  3167  		x := s.expr(n.X)
  3168  		if to == from {
  3169  			return x
  3170  		}
  3171  
  3172  		// Special case for not confusing GC and liveness.
  3173  		// We don't want pointers accidentally classified
  3174  		// as not-pointers or vice-versa because of copy
  3175  		// elision.
  3176  		if to.IsPtrShaped() != from.IsPtrShaped() {
  3177  			return s.newValue2(ssa.OpConvert, to, x, s.mem())
  3178  		}
  3179  
  3180  		v := s.newValue1(ssa.OpCopy, to, x) // ensure that v has the right type
  3181  
  3182  		// CONVNOP closure
  3183  		if to.Kind() == types.TFUNC && from.IsPtrShaped() {
  3184  			return v
  3185  		}
  3186  
  3187  		// named <--> unnamed type or typed <--> untyped const
  3188  		if from.Kind() == to.Kind() {
  3189  			return v
  3190  		}
  3191  
  3192  		// unsafe.Pointer <--> *T
  3193  		if to.IsUnsafePtr() && from.IsPtrShaped() || from.IsUnsafePtr() && to.IsPtrShaped() {
  3194  			if s.checkPtrEnabled && checkPtrOK && to.IsPtr() && from.IsUnsafePtr() {
  3195  				s.checkPtrAlignment(n, v, nil)
  3196  			}
  3197  			return v
  3198  		}
  3199  
  3200  		// map <--> *internal/runtime/maps.Map
  3201  		mt := types.NewPtr(reflectdata.MapType())
  3202  		if to.Kind() == types.TMAP && from == mt {
  3203  			return v
  3204  		}
  3205  
  3206  		types.CalcSize(from)
  3207  		types.CalcSize(to)
  3208  		if from.Size() != to.Size() {
  3209  			s.Fatalf("CONVNOP width mismatch %v (%d) -> %v (%d)\n", from, from.Size(), to, to.Size())
  3210  			return nil
  3211  		}
  3212  		if etypesign(from.Kind()) != etypesign(to.Kind()) {
  3213  			s.Fatalf("CONVNOP sign mismatch %v (%s) -> %v (%s)\n", from, from.Kind(), to, to.Kind())
  3214  			return nil
  3215  		}
  3216  
  3217  		if base.Flag.Cfg.Instrumenting {
  3218  			// These appear to be fine, but they fail the
  3219  			// integer constraint below, so okay them here.
  3220  			// Sample non-integer conversion: map[string]string -> *uint8
  3221  			return v
  3222  		}
  3223  
  3224  		if etypesign(from.Kind()) == 0 {
  3225  			s.Fatalf("CONVNOP unrecognized non-integer %v -> %v\n", from, to)
  3226  			return nil
  3227  		}
  3228  
  3229  		// integer, same width, same sign
  3230  		return v
  3231  
  3232  	case ir.OCONV:
  3233  		n := n.(*ir.ConvExpr)
  3234  		x := s.expr(n.X)
  3235  		return s.conv(n, x, n.X.Type(), n.Type())
  3236  
  3237  	case ir.ODOTTYPE:
  3238  		n := n.(*ir.TypeAssertExpr)
  3239  		res, _ := s.dottype(n, false)
  3240  		return res
  3241  
  3242  	case ir.ODYNAMICDOTTYPE:
  3243  		n := n.(*ir.DynamicTypeAssertExpr)
  3244  		res, _ := s.dynamicDottype(n, false)
  3245  		return res
  3246  
  3247  	// binary ops
  3248  	case ir.OLT, ir.OEQ, ir.ONE, ir.OLE, ir.OGE, ir.OGT:
  3249  		n := n.(*ir.BinaryExpr)
  3250  		a := s.expr(n.X)
  3251  		b := s.expr(n.Y)
  3252  		if n.X.Type().IsComplex() {
  3253  			pt := types.FloatForComplex(n.X.Type())
  3254  			op := s.ssaOp(ir.OEQ, pt)
  3255  			r := s.newValueOrSfCall2(op, types.Types[types.TBOOL], s.newValue1(ssa.OpComplexReal, pt, a), s.newValue1(ssa.OpComplexReal, pt, b))
  3256  			i := s.newValueOrSfCall2(op, types.Types[types.TBOOL], s.newValue1(ssa.OpComplexImag, pt, a), s.newValue1(ssa.OpComplexImag, pt, b))
  3257  			c := s.newValue2(ssa.OpAndB, types.Types[types.TBOOL], r, i)
  3258  			switch n.Op() {
  3259  			case ir.OEQ:
  3260  				return c
  3261  			case ir.ONE:
  3262  				return s.newValue1(ssa.OpNot, types.Types[types.TBOOL], c)
  3263  			default:
  3264  				s.Fatalf("ordered complex compare %v", n.Op())
  3265  			}
  3266  		}
  3267  
  3268  		// Convert OGE and OGT into OLE and OLT.
  3269  		op := n.Op()
  3270  		switch op {
  3271  		case ir.OGE:
  3272  			op, a, b = ir.OLE, b, a
  3273  		case ir.OGT:
  3274  			op, a, b = ir.OLT, b, a
  3275  		}
  3276  		if n.X.Type().IsFloat() {
  3277  			// float comparison
  3278  			return s.newValueOrSfCall2(s.ssaOp(op, n.X.Type()), types.Types[types.TBOOL], a, b)
  3279  		}
  3280  		// integer comparison
  3281  		return s.newValue2(s.ssaOp(op, n.X.Type()), types.Types[types.TBOOL], a, b)
  3282  	case ir.OMUL:
  3283  		n := n.(*ir.BinaryExpr)
  3284  		a := s.expr(n.X)
  3285  		b := s.expr(n.Y)
  3286  		if n.Type().IsComplex() {
  3287  			mulop := ssa.OpMul64F
  3288  			addop := ssa.OpAdd64F
  3289  			subop := ssa.OpSub64F
  3290  			pt := types.FloatForComplex(n.Type()) // Could be Float32 or Float64
  3291  			wt := types.Types[types.TFLOAT64]     // Compute in Float64 to minimize cancellation error
  3292  
  3293  			areal := s.newValue1(ssa.OpComplexReal, pt, a)
  3294  			breal := s.newValue1(ssa.OpComplexReal, pt, b)
  3295  			aimag := s.newValue1(ssa.OpComplexImag, pt, a)
  3296  			bimag := s.newValue1(ssa.OpComplexImag, pt, b)
  3297  
  3298  			if pt != wt { // Widen for calculation
  3299  				areal = s.newValueOrSfCall1(ssa.OpCvt32Fto64F, wt, areal)
  3300  				breal = s.newValueOrSfCall1(ssa.OpCvt32Fto64F, wt, breal)
  3301  				aimag = s.newValueOrSfCall1(ssa.OpCvt32Fto64F, wt, aimag)
  3302  				bimag = s.newValueOrSfCall1(ssa.OpCvt32Fto64F, wt, bimag)
  3303  			}
  3304  
  3305  			xreal := s.newValueOrSfCall2(subop, wt, s.newValueOrSfCall2(mulop, wt, areal, breal), s.newValueOrSfCall2(mulop, wt, aimag, bimag))
  3306  			ximag := s.newValueOrSfCall2(addop, wt, s.newValueOrSfCall2(mulop, wt, areal, bimag), s.newValueOrSfCall2(mulop, wt, aimag, breal))
  3307  
  3308  			if pt != wt { // Narrow to store back
  3309  				xreal = s.newValueOrSfCall1(ssa.OpCvt64Fto32F, pt, xreal)
  3310  				ximag = s.newValueOrSfCall1(ssa.OpCvt64Fto32F, pt, ximag)
  3311  			}
  3312  
  3313  			return s.newValue2(ssa.OpComplexMake, n.Type(), xreal, ximag)
  3314  		}
  3315  
  3316  		if n.Type().IsFloat() {
  3317  			return s.newValueOrSfCall2(s.ssaOp(n.Op(), n.Type()), a.Type, a, b)
  3318  		}
  3319  
  3320  		return s.newValue2(s.ssaOp(n.Op(), n.Type()), a.Type, a, b)
  3321  
  3322  	case ir.ODIV:
  3323  		n := n.(*ir.BinaryExpr)
  3324  		a := s.expr(n.X)
  3325  		b := s.expr(n.Y)
  3326  		if n.Type().IsComplex() {
  3327  			// TODO this is not executed because the front-end substitutes a runtime call.
  3328  			// That probably ought to change; with modest optimization the widen/narrow
  3329  			// conversions could all be elided in larger expression trees.
  3330  			mulop := ssa.OpMul64F
  3331  			addop := ssa.OpAdd64F
  3332  			subop := ssa.OpSub64F
  3333  			divop := ssa.OpDiv64F
  3334  			pt := types.FloatForComplex(n.Type()) // Could be Float32 or Float64
  3335  			wt := types.Types[types.TFLOAT64]     // Compute in Float64 to minimize cancellation error
  3336  
  3337  			areal := s.newValue1(ssa.OpComplexReal, pt, a)
  3338  			breal := s.newValue1(ssa.OpComplexReal, pt, b)
  3339  			aimag := s.newValue1(ssa.OpComplexImag, pt, a)
  3340  			bimag := s.newValue1(ssa.OpComplexImag, pt, b)
  3341  
  3342  			if pt != wt { // Widen for calculation
  3343  				areal = s.newValueOrSfCall1(ssa.OpCvt32Fto64F, wt, areal)
  3344  				breal = s.newValueOrSfCall1(ssa.OpCvt32Fto64F, wt, breal)
  3345  				aimag = s.newValueOrSfCall1(ssa.OpCvt32Fto64F, wt, aimag)
  3346  				bimag = s.newValueOrSfCall1(ssa.OpCvt32Fto64F, wt, bimag)
  3347  			}
  3348  
  3349  			denom := s.newValueOrSfCall2(addop, wt, s.newValueOrSfCall2(mulop, wt, breal, breal), s.newValueOrSfCall2(mulop, wt, bimag, bimag))
  3350  			xreal := s.newValueOrSfCall2(addop, wt, s.newValueOrSfCall2(mulop, wt, areal, breal), s.newValueOrSfCall2(mulop, wt, aimag, bimag))
  3351  			ximag := s.newValueOrSfCall2(subop, wt, s.newValueOrSfCall2(mulop, wt, aimag, breal), s.newValueOrSfCall2(mulop, wt, areal, bimag))
  3352  
  3353  			// TODO not sure if this is best done in wide precision or narrow
  3354  			// Double-rounding might be an issue.
  3355  			// Note that the pre-SSA implementation does the entire calculation
  3356  			// in wide format, so wide is compatible.
  3357  			xreal = s.newValueOrSfCall2(divop, wt, xreal, denom)
  3358  			ximag = s.newValueOrSfCall2(divop, wt, ximag, denom)
  3359  
  3360  			if pt != wt { // Narrow to store back
  3361  				xreal = s.newValueOrSfCall1(ssa.OpCvt64Fto32F, pt, xreal)
  3362  				ximag = s.newValueOrSfCall1(ssa.OpCvt64Fto32F, pt, ximag)
  3363  			}
  3364  			return s.newValue2(ssa.OpComplexMake, n.Type(), xreal, ximag)
  3365  		}
  3366  		if n.Type().IsFloat() {
  3367  			return s.newValueOrSfCall2(s.ssaOp(n.Op(), n.Type()), a.Type, a, b)
  3368  		}
  3369  		return s.intDivide(n, a, b)
  3370  	case ir.OMOD:
  3371  		n := n.(*ir.BinaryExpr)
  3372  		a := s.expr(n.X)
  3373  		b := s.expr(n.Y)
  3374  		return s.intDivide(n, a, b)
  3375  	case ir.OADD, ir.OSUB:
  3376  		n := n.(*ir.BinaryExpr)
  3377  		a := s.expr(n.X)
  3378  		b := s.expr(n.Y)
  3379  		if n.Type().IsComplex() {
  3380  			pt := types.FloatForComplex(n.Type())
  3381  			op := s.ssaOp(n.Op(), pt)
  3382  			return s.newValue2(ssa.OpComplexMake, n.Type(),
  3383  				s.newValueOrSfCall2(op, pt, s.newValue1(ssa.OpComplexReal, pt, a), s.newValue1(ssa.OpComplexReal, pt, b)),
  3384  				s.newValueOrSfCall2(op, pt, s.newValue1(ssa.OpComplexImag, pt, a), s.newValue1(ssa.OpComplexImag, pt, b)))
  3385  		}
  3386  		if n.Type().IsFloat() {
  3387  			return s.newValueOrSfCall2(s.ssaOp(n.Op(), n.Type()), a.Type, a, b)
  3388  		}
  3389  		return s.newValue2(s.ssaOp(n.Op(), n.Type()), a.Type, a, b)
  3390  	case ir.OAND, ir.OOR, ir.OXOR:
  3391  		n := n.(*ir.BinaryExpr)
  3392  		a := s.expr(n.X)
  3393  		b := s.expr(n.Y)
  3394  		return s.newValue2(s.ssaOp(n.Op(), n.Type()), a.Type, a, b)
  3395  	case ir.OANDNOT:
  3396  		n := n.(*ir.BinaryExpr)
  3397  		a := s.expr(n.X)
  3398  		b := s.expr(n.Y)
  3399  		b = s.newValue1(s.ssaOp(ir.OBITNOT, b.Type), b.Type, b)
  3400  		return s.newValue2(s.ssaOp(ir.OAND, n.Type()), a.Type, a, b)
  3401  	case ir.OLSH, ir.ORSH:
  3402  		n := n.(*ir.BinaryExpr)
  3403  		a := s.expr(n.X)
  3404  		b := s.expr(n.Y)
  3405  		bt := b.Type
  3406  		if bt.IsSigned() {
  3407  			cmp := s.newValue2(s.ssaOp(ir.OLE, bt), types.Types[types.TBOOL], s.zeroVal(bt), b)
  3408  			s.check(cmp, ir.Syms.Panicshift)
  3409  			bt = bt.ToUnsigned()
  3410  		}
  3411  		return s.newValue2(s.ssaShiftOp(n.Op(), n.Type(), bt), a.Type, a, b)
  3412  	case ir.OANDAND, ir.OOROR:
  3413  		// To implement OANDAND (and OOROR), we introduce a
  3414  		// new temporary variable to hold the result. The
  3415  		// variable is associated with the OANDAND node in the
  3416  		// s.vars table (normally variables are only
  3417  		// associated with ONAME nodes). We convert
  3418  		//     A && B
  3419  		// to
  3420  		//     var = A
  3421  		//     if var {
  3422  		//         var = B
  3423  		//     }
  3424  		// Using var in the subsequent block introduces the
  3425  		// necessary phi variable.
  3426  		n := n.(*ir.LogicalExpr)
  3427  		el := s.expr(n.X)
  3428  		s.vars[n] = el
  3429  
  3430  		b := s.endBlock()
  3431  		b.Kind = block.BlockIf
  3432  		b.SetControl(el)
  3433  		// In theory, we should set b.Likely here based on context.
  3434  		// However, gc only gives us likeliness hints
  3435  		// in a single place, for plain OIF statements,
  3436  		// and passing around context is finicky, so don't bother for now.
  3437  
  3438  		bRight := s.f.NewBlock(block.BlockPlain)
  3439  		bResult := s.f.NewBlock(block.BlockPlain)
  3440  		if n.Op() == ir.OANDAND {
  3441  			b.AddEdgeTo(bRight)
  3442  			b.AddEdgeTo(bResult)
  3443  		} else if n.Op() == ir.OOROR {
  3444  			b.AddEdgeTo(bResult)
  3445  			b.AddEdgeTo(bRight)
  3446  		}
  3447  
  3448  		s.startBlock(bRight)
  3449  		er := s.expr(n.Y)
  3450  		s.vars[n] = er
  3451  
  3452  		b = s.endBlock()
  3453  		b.AddEdgeTo(bResult)
  3454  
  3455  		s.startBlock(bResult)
  3456  		return s.variable(n, types.Types[types.TBOOL])
  3457  	case ir.OCOMPLEX:
  3458  		n := n.(*ir.BinaryExpr)
  3459  		r := s.expr(n.X)
  3460  		i := s.expr(n.Y)
  3461  		return s.newValue2(ssa.OpComplexMake, n.Type(), r, i)
  3462  
  3463  	// unary ops
  3464  	case ir.ONEG:
  3465  		n := n.(*ir.UnaryExpr)
  3466  		a := s.expr(n.X)
  3467  		if n.Type().IsComplex() {
  3468  			tp := types.FloatForComplex(n.Type())
  3469  			negop := s.ssaOp(n.Op(), tp)
  3470  			return s.newValue2(ssa.OpComplexMake, n.Type(),
  3471  				s.newValue1(negop, tp, s.newValue1(ssa.OpComplexReal, tp, a)),
  3472  				s.newValue1(negop, tp, s.newValue1(ssa.OpComplexImag, tp, a)))
  3473  		}
  3474  		return s.newValue1(s.ssaOp(n.Op(), n.Type()), a.Type, a)
  3475  	case ir.ONOT, ir.OBITNOT:
  3476  		n := n.(*ir.UnaryExpr)
  3477  		a := s.expr(n.X)
  3478  		return s.newValue1(s.ssaOp(n.Op(), n.Type()), a.Type, a)
  3479  	case ir.OIMAG, ir.OREAL:
  3480  		n := n.(*ir.UnaryExpr)
  3481  		a := s.expr(n.X)
  3482  		return s.newValue1(s.ssaOp(n.Op(), n.X.Type()), n.Type(), a)
  3483  	case ir.OPLUS:
  3484  		n := n.(*ir.UnaryExpr)
  3485  		return s.expr(n.X)
  3486  
  3487  	case ir.OADDR:
  3488  		n := n.(*ir.AddrExpr)
  3489  		return s.addr(n.X)
  3490  
  3491  	case ir.ORESULT:
  3492  		n := n.(*ir.ResultExpr)
  3493  		if s.prevCall == nil || s.prevCall.Op != ssa.OpStaticLECall && s.prevCall.Op != ssa.OpInterLECall && s.prevCall.Op != ssa.OpClosureLECall {
  3494  			panic("Expected to see a previous call")
  3495  		}
  3496  		which := n.Index
  3497  		if which == -1 {
  3498  			panic(fmt.Errorf("ORESULT %v does not match call %s", n, s.prevCall))
  3499  		}
  3500  		return s.resultOfCall(s.prevCall, which, n.Type())
  3501  
  3502  	case ir.ODEREF:
  3503  		n := n.(*ir.StarExpr)
  3504  		p := s.exprPtr(n.X, n.Bounded(), n.Pos())
  3505  		return s.load(n.Type(), p)
  3506  
  3507  	case ir.ODOT:
  3508  		n := n.(*ir.SelectorExpr)
  3509  		if n.X.Op() == ir.OSTRUCTLIT {
  3510  			// All literals with nonzero fields have already been
  3511  			// rewritten during walk. Any that remain are just T{}
  3512  			// or equivalents. Use the zero value.
  3513  			if !ir.IsZero(n.X) {
  3514  				s.Fatalf("literal with nonzero value in SSA: %v", n.X)
  3515  			}
  3516  			return s.zeroVal(n.Type())
  3517  		}
  3518  		// If n is addressable and can't be represented in
  3519  		// SSA, then load just the selected field. This
  3520  		// prevents false memory dependencies in race/msan/asan
  3521  		// instrumentation.
  3522  		if ir.IsAddressable(n) && !s.canSSA(n) {
  3523  			p := s.addr(n)
  3524  			return s.load(n.Type(), p)
  3525  		}
  3526  		v := s.expr(n.X)
  3527  		return s.newValue1I(ssa.OpStructSelect, n.Type(), int64(fieldIdx(n)), v)
  3528  
  3529  	case ir.ODOTPTR:
  3530  		n := n.(*ir.SelectorExpr)
  3531  		p := s.exprPtr(n.X, n.Bounded(), n.Pos())
  3532  		p = s.newValue1I(ssa.OpOffPtr, types.NewPtr(n.Type()), n.Offset(), p)
  3533  		return s.load(n.Type(), p)
  3534  
  3535  	case ir.OINDEX:
  3536  		n := n.(*ir.IndexExpr)
  3537  		switch {
  3538  		case n.X.Type().IsString():
  3539  			if n.Bounded() && ir.IsConst(n.X, constant.String) && ir.IsConst(n.Index, constant.Int) {
  3540  				// Replace "abc"[1] with 'b'.
  3541  				// Delayed until now because "abc"[1] is not an ideal constant.
  3542  				// See test/fixedbugs/issue11370.go.
  3543  				return s.newValue0I(ssa.OpConst8, types.Types[types.TUINT8], int64(int8(ir.StringVal(n.X)[ir.Int64Val(n.Index)])))
  3544  			}
  3545  			a := s.expr(n.X)
  3546  			i := s.expr(n.Index)
  3547  			len := s.newValue1(ssa.OpStringLen, types.Types[types.TINT], a)
  3548  			i = s.boundsCheck(i, len, ssa.BoundsIndex, n.Bounded())
  3549  			ptrtyp := s.f.Config.Types.BytePtr
  3550  			ptr := s.newValue1(ssa.OpStringPtr, ptrtyp, a)
  3551  			if ir.IsConst(n.Index, constant.Int) {
  3552  				ptr = s.newValue1I(ssa.OpOffPtr, ptrtyp, ir.Int64Val(n.Index), ptr)
  3553  			} else {
  3554  				ptr = s.newValue2(ssa.OpAddPtr, ptrtyp, ptr, i)
  3555  			}
  3556  			return s.load(types.Types[types.TUINT8], ptr)
  3557  		case n.X.Type().IsSlice():
  3558  			p := s.addr(n)
  3559  			return s.load(n.X.Type().Elem(), p)
  3560  		case n.X.Type().IsArray():
  3561  			if ssa.CanSSA(n.X.Type()) {
  3562  				// SSA can handle arrays of length at most 1.
  3563  				bound := n.X.Type().NumElem()
  3564  				a := s.expr(n.X)
  3565  				i := s.expr(n.Index)
  3566  				len := s.constInt(types.Types[types.TINT], bound)
  3567  				if bound == 0 {
  3568  					// Bounds check will never succeed.
  3569  					s.boundsCheck(i, len, ssa.BoundsIndex, false)
  3570  					// The return value won't be live. In case bounds checks
  3571  					// are turned off, load from (*T)(nil) to cause a segfault.
  3572  					return s.load(n.Type(), s.constNil(n.Type().PtrTo()))
  3573  				}
  3574  				s.boundsCheck(i, len, ssa.BoundsIndex, n.Bounded()) // checks i == 0
  3575  				return s.newValue1I(ssa.OpArraySelect, n.Type(), 0, a)
  3576  			}
  3577  			p := s.addr(n)
  3578  			return s.load(n.X.Type().Elem(), p)
  3579  		default:
  3580  			s.Fatalf("bad type for index %v", n.X.Type())
  3581  			return nil
  3582  		}
  3583  
  3584  	case ir.OLEN, ir.OCAP:
  3585  		n := n.(*ir.UnaryExpr)
  3586  		// Note: all constant cases are handled by the frontend. If len or cap
  3587  		// makes it here, we want the side effects of the argument. See issue 72844.
  3588  		a := s.expr(n.X)
  3589  		t := n.X.Type()
  3590  		switch {
  3591  		case t.IsSlice():
  3592  			op := ssa.OpSliceLen
  3593  			if n.Op() == ir.OCAP {
  3594  				op = ssa.OpSliceCap
  3595  			}
  3596  			return s.newValue1(op, types.Types[types.TINT], a)
  3597  		case t.IsString(): // string; not reachable for OCAP
  3598  			return s.newValue1(ssa.OpStringLen, types.Types[types.TINT], a)
  3599  		case t.IsMap(), t.IsChan():
  3600  			return s.referenceTypeBuiltin(n, a)
  3601  		case t.IsArray():
  3602  			return s.constInt(types.Types[types.TINT], t.NumElem())
  3603  		case t.IsPtr() && t.Elem().IsArray():
  3604  			return s.constInt(types.Types[types.TINT], t.Elem().NumElem())
  3605  		default:
  3606  			s.Fatalf("bad type in len/cap: %v", t)
  3607  			return nil
  3608  		}
  3609  
  3610  	case ir.OSPTR:
  3611  		n := n.(*ir.UnaryExpr)
  3612  		a := s.expr(n.X)
  3613  		if n.X.Type().IsSlice() {
  3614  			if n.Bounded() {
  3615  				return s.newValue1(ssa.OpSlicePtr, n.Type(), a)
  3616  			}
  3617  			return s.newValue1(ssa.OpSlicePtrUnchecked, n.Type(), a)
  3618  		} else {
  3619  			return s.newValue1(ssa.OpStringPtr, n.Type(), a)
  3620  		}
  3621  
  3622  	case ir.OITAB:
  3623  		n := n.(*ir.UnaryExpr)
  3624  		a := s.expr(n.X)
  3625  		return s.newValue1(ssa.OpITab, n.Type(), a)
  3626  
  3627  	case ir.OIDATA:
  3628  		n := n.(*ir.UnaryExpr)
  3629  		a := s.expr(n.X)
  3630  		return s.newValue1(ssa.OpIData, n.Type(), a)
  3631  
  3632  	case ir.OMAKEFACE:
  3633  		n := n.(*ir.BinaryExpr)
  3634  		tab := s.expr(n.X)
  3635  		data := s.expr(n.Y)
  3636  		return s.newValue2(ssa.OpIMake, n.Type(), tab, data)
  3637  
  3638  	case ir.OSLICEHEADER:
  3639  		n := n.(*ir.SliceHeaderExpr)
  3640  		p := s.expr(n.Ptr)
  3641  		l := s.expr(n.Len)
  3642  		c := s.expr(n.Cap)
  3643  		return s.newValue3(ssa.OpSliceMake, n.Type(), p, l, c)
  3644  
  3645  	case ir.OSTRINGHEADER:
  3646  		n := n.(*ir.StringHeaderExpr)
  3647  		p := s.expr(n.Ptr)
  3648  		l := s.expr(n.Len)
  3649  		return s.newValue2(ssa.OpStringMake, n.Type(), p, l)
  3650  
  3651  	case ir.OSLICE, ir.OSLICEARR, ir.OSLICE3, ir.OSLICE3ARR:
  3652  		n := n.(*ir.SliceExpr)
  3653  		check := s.checkPtrEnabled && n.Op() == ir.OSLICE3ARR && n.X.Op() == ir.OCONVNOP && n.X.(*ir.ConvExpr).X.Type().IsUnsafePtr()
  3654  		v := s.exprCheckPtr(n.X, !check)
  3655  		var i, j, k *ssa.Value
  3656  		if n.Low != nil {
  3657  			i = s.expr(n.Low)
  3658  		}
  3659  		if n.High != nil {
  3660  			j = s.expr(n.High)
  3661  		}
  3662  		if n.Max != nil {
  3663  			k = s.expr(n.Max)
  3664  		}
  3665  		p, l, c := s.slice(v, i, j, k, n.Bounded())
  3666  		if check {
  3667  			// Emit checkptr instrumentation after bound check to prevent false positive, see #46938.
  3668  			s.checkPtrAlignment(n.X.(*ir.ConvExpr), v, s.conv(n.Max, k, k.Type, types.Types[types.TUINTPTR]))
  3669  		}
  3670  		return s.newValue3(ssa.OpSliceMake, n.Type(), p, l, c)
  3671  
  3672  	case ir.OSLICESTR:
  3673  		n := n.(*ir.SliceExpr)
  3674  		v := s.expr(n.X)
  3675  		var i, j *ssa.Value
  3676  		if n.Low != nil {
  3677  			i = s.expr(n.Low)
  3678  		}
  3679  		if n.High != nil {
  3680  			j = s.expr(n.High)
  3681  		}
  3682  		p, l, _ := s.slice(v, i, j, nil, n.Bounded())
  3683  		return s.newValue2(ssa.OpStringMake, n.Type(), p, l)
  3684  
  3685  	case ir.OSLICE2ARRPTR:
  3686  		// if arrlen > slice.len {
  3687  		//   panic(...)
  3688  		// }
  3689  		// slice.ptr
  3690  		n := n.(*ir.ConvExpr)
  3691  		v := s.expr(n.X)
  3692  		nelem := n.Type().Elem().NumElem()
  3693  		arrlen := s.constInt(types.Types[types.TINT], nelem)
  3694  		cap := s.newValue1(ssa.OpSliceLen, types.Types[types.TINT], v)
  3695  		s.boundsCheck(arrlen, cap, ssa.BoundsConvert, false)
  3696  		op := ssa.OpSlicePtr
  3697  		if nelem == 0 {
  3698  			op = ssa.OpSlicePtrUnchecked
  3699  		}
  3700  		return s.newValue1(op, n.Type(), v)
  3701  
  3702  	case ir.OCALLFUNC:
  3703  		n := n.(*ir.CallExpr)
  3704  		if ir.IsIntrinsicCall(n) {
  3705  			return s.intrinsicCall(n)
  3706  		}
  3707  		fallthrough
  3708  
  3709  	case ir.OCALLINTER:
  3710  		n := n.(*ir.CallExpr)
  3711  		return s.callResult(n, callNormal)
  3712  
  3713  	case ir.OGETG:
  3714  		n := n.(*ir.CallExpr)
  3715  		return s.newValue1(ssa.OpGetG, n.Type(), s.mem())
  3716  
  3717  	case ir.OGETCALLERSP:
  3718  		n := n.(*ir.CallExpr)
  3719  		return s.newValue1(ssa.OpGetCallerSP, n.Type(), s.mem())
  3720  
  3721  	case ir.OAPPEND:
  3722  		return s.append(n.(*ir.CallExpr), false)
  3723  
  3724  	case ir.OMOVE2HEAP:
  3725  		return s.move2heap(n.(*ir.MoveToHeapExpr))
  3726  
  3727  	case ir.OMIN, ir.OMAX:
  3728  		return s.minMax(n.(*ir.CallExpr))
  3729  
  3730  	case ir.OSTRUCTLIT, ir.OARRAYLIT:
  3731  		// All literals with nonzero fields have already been
  3732  		// rewritten during walk. Any that remain are just T{}
  3733  		// or equivalents. Use the zero value.
  3734  		n := n.(*ir.CompLitExpr)
  3735  		if !ir.IsZero(n) {
  3736  			s.Fatalf("literal with nonzero value in SSA: %v", n)
  3737  		}
  3738  		return s.zeroVal(n.Type())
  3739  
  3740  	case ir.ONEW:
  3741  		n := n.(*ir.UnaryExpr)
  3742  		if x, ok := n.X.(*ir.DynamicType); ok && x.Op() == ir.ODYNAMICTYPE {
  3743  			return s.newObjectNonSpecialized(n.Type().Elem(), s.expr(x.RType))
  3744  		}
  3745  		return s.newObject(n.Type().Elem())
  3746  
  3747  	case ir.OUNSAFEADD:
  3748  		n := n.(*ir.BinaryExpr)
  3749  		ptr := s.expr(n.X)
  3750  		len := s.expr(n.Y)
  3751  
  3752  		// Force len to uintptr to prevent misuse of garbage bits in the
  3753  		// upper part of the register (#48536).
  3754  		len = s.conv(n, len, len.Type, types.Types[types.TUINTPTR])
  3755  
  3756  		return s.newValue2(ssa.OpAddPtr, n.Type(), ptr, len)
  3757  
  3758  	default:
  3759  		s.Fatalf("unhandled expr %v", n.Op())
  3760  		return nil
  3761  	}
  3762  }
  3763  
  3764  func (s *state) resultOfCall(c *ssa.Value, which int64, t *types.Type) *ssa.Value {
  3765  	aux := c.Aux.(*ssa.AuxCall)
  3766  	pa := aux.ParamAssignmentForResult(which)
  3767  	// TODO(register args) determine if in-memory TypeOK is better loaded early from SelectNAddr or later when SelectN is expanded.
  3768  	// SelectN is better for pattern-matching and possible call-aware analysis we might want to do in the future.
  3769  	if len(pa.Registers) == 0 && !ssa.CanSSA(t) {
  3770  		addr := s.newValue1I(ssa.OpSelectNAddr, types.NewPtr(t), which, c)
  3771  		return s.rawLoad(t, addr)
  3772  	}
  3773  	return s.newValue1I(ssa.OpSelectN, t, which, c)
  3774  }
  3775  
  3776  func (s *state) resultAddrOfCall(c *ssa.Value, which int64, t *types.Type) *ssa.Value {
  3777  	aux := c.Aux.(*ssa.AuxCall)
  3778  	pa := aux.ParamAssignmentForResult(which)
  3779  	if len(pa.Registers) == 0 {
  3780  		return s.newValue1I(ssa.OpSelectNAddr, types.NewPtr(t), which, c)
  3781  	}
  3782  	_, addr := s.temp(c.Pos, t)
  3783  	rval := s.newValue1I(ssa.OpSelectN, t, which, c)
  3784  	s.vars[memVar] = s.newValue3Apos(ssa.OpStore, types.TypeMem, t, addr, rval, s.mem(), false)
  3785  	return addr
  3786  }
  3787  
  3788  // Get backing store information for an append call.
  3789  func (s *state) getBackingStoreInfoForAppend(n *ir.CallExpr) *backingStoreInfo {
  3790  	if n.Esc() != ir.EscNone {
  3791  		return nil
  3792  	}
  3793  	return s.getBackingStoreInfo(n.Args[0])
  3794  }
  3795  func (s *state) getBackingStoreInfo(n ir.Node) *backingStoreInfo {
  3796  	t := n.Type()
  3797  	et := t.Elem()
  3798  	maxStackSize := int64(base.Debug.VariableMakeThreshold)
  3799  	if et.Size() == 0 || et.Size() > maxStackSize {
  3800  		return nil
  3801  	}
  3802  	if base.Flag.N != 0 {
  3803  		return nil
  3804  	}
  3805  	if !base.VariableMakeHash.MatchPos(n.Pos(), nil) {
  3806  		return nil
  3807  	}
  3808  	i := s.backingStores[n]
  3809  	if i != nil {
  3810  		return i
  3811  	}
  3812  
  3813  	// Build type of backing store.
  3814  	K := maxStackSize / et.Size() // rounds down
  3815  	KT := types.NewArray(et, K)
  3816  	KT.SetNoalg(true)
  3817  	types.CalcArraySize(KT)
  3818  	// Align more than naturally for the type KT. See issue 73199.
  3819  	align := types.NewArray(types.Types[types.TUINTPTR], 0)
  3820  	types.CalcArraySize(align)
  3821  	storeTyp := types.NewStruct([]*types.Field{
  3822  		{Sym: types.BlankSym, Type: align},
  3823  		{Sym: types.BlankSym, Type: KT},
  3824  	})
  3825  	storeTyp.SetNoalg(true)
  3826  	types.CalcStructSize(storeTyp)
  3827  
  3828  	// Make backing store variable.
  3829  	backingStore := typecheck.TempAt(n.Pos(), s.curfn, storeTyp)
  3830  	backingStore.SetAddrtaken(true)
  3831  
  3832  	// Make "used" boolean.
  3833  	used := typecheck.TempAt(n.Pos(), s.curfn, types.Types[types.TBOOL])
  3834  	if s.curBlock == s.f.Entry {
  3835  		s.vars[used] = s.constBool(false)
  3836  	} else {
  3837  		// initialize this variable at end of entry block
  3838  		s.defvars[s.f.Entry.ID][used] = s.constBool(false)
  3839  	}
  3840  
  3841  	// Initialize an info structure.
  3842  	if s.backingStores == nil {
  3843  		s.backingStores = map[ir.Node]*backingStoreInfo{}
  3844  	}
  3845  	i = &backingStoreInfo{K: K, store: backingStore, used: used, usedStatic: false}
  3846  	s.backingStores[n] = i
  3847  	return i
  3848  }
  3849  
  3850  // append converts an OAPPEND node to SSA.
  3851  // If inplace is false, it converts the OAPPEND expression n to an ssa.Value,
  3852  // adds it to s, and returns the Value.
  3853  // If inplace is true, it writes the result of the OAPPEND expression n
  3854  // back to the slice being appended to, and returns nil.
  3855  // inplace MUST be set to false if the slice can be SSA'd.
  3856  // Note: this code only handles fixed-count appends. Dotdotdot appends
  3857  // have already been rewritten at this point (by walk).
  3858  func (s *state) append(n *ir.CallExpr, inplace bool) *ssa.Value {
  3859  	// If inplace is false, process as expression "append(s, e1, e2, e3)":
  3860  	//
  3861  	// ptr, len, cap := s
  3862  	// len += 3
  3863  	// if uint(len) > uint(cap) {
  3864  	//     ptr, len, cap = growslice(ptr, len, cap, 3, typ)
  3865  	//     Note that len is unmodified by growslice.
  3866  	// }
  3867  	// // with write barriers, if needed:
  3868  	// *(ptr+(len-3)) = e1
  3869  	// *(ptr+(len-2)) = e2
  3870  	// *(ptr+(len-1)) = e3
  3871  	// return makeslice(ptr, len, cap)
  3872  	//
  3873  	//
  3874  	// If inplace is true, process as statement "s = append(s, e1, e2, e3)":
  3875  	//
  3876  	// a := &s
  3877  	// ptr, len, cap := s
  3878  	// len += 3
  3879  	// if uint(len) > uint(cap) {
  3880  	//    ptr, len, cap = growslice(ptr, len, cap, 3, typ)
  3881  	//    vardef(a)    // if necessary, advise liveness we are writing a new a
  3882  	//    *a.cap = cap // write before ptr to avoid a spill
  3883  	//    *a.ptr = ptr // with write barrier
  3884  	// }
  3885  	// *a.len = len
  3886  	// // with write barriers, if needed:
  3887  	// *(ptr+(len-3)) = e1
  3888  	// *(ptr+(len-2)) = e2
  3889  	// *(ptr+(len-1)) = e3
  3890  
  3891  	et := n.Type().Elem()
  3892  	pt := types.NewPtr(et)
  3893  
  3894  	// Evaluate slice
  3895  	sn := n.Args[0] // the slice node is the first in the list
  3896  	var slice, addr *ssa.Value
  3897  	if inplace {
  3898  		addr = s.addr(sn)
  3899  		slice = s.load(n.Type(), addr)
  3900  	} else {
  3901  		slice = s.expr(sn)
  3902  	}
  3903  
  3904  	// Allocate new blocks
  3905  	grow := s.f.NewBlock(block.BlockPlain)
  3906  	assign := s.f.NewBlock(block.BlockPlain)
  3907  
  3908  	// Decomposse input slice.
  3909  	p := s.newValue1(ssa.OpSlicePtr, pt, slice)
  3910  	l := s.newValue1(ssa.OpSliceLen, types.Types[types.TINT], slice)
  3911  	c := s.newValue1(ssa.OpSliceCap, types.Types[types.TINT], slice)
  3912  
  3913  	// Add number of new elements to length.
  3914  	nargs := s.constInt(types.Types[types.TINT], int64(len(n.Args)-1))
  3915  	oldLen := l
  3916  	l = s.newValue2(s.ssaOp(ir.OADD, types.Types[types.TINT]), types.Types[types.TINT], l, nargs)
  3917  
  3918  	// Decide if we need to grow
  3919  	cmp := s.newValue2(s.ssaOp(ir.OLT, types.Types[types.TUINT]), types.Types[types.TBOOL], c, l)
  3920  
  3921  	// Record values of ptr/len/cap before branch.
  3922  	s.vars[ptrVar] = p
  3923  	s.vars[lenVar] = l
  3924  	if !inplace {
  3925  		s.vars[capVar] = c
  3926  	}
  3927  
  3928  	b := s.endBlock()
  3929  	b.Kind = block.BlockIf
  3930  	b.Likely = ssa.BranchUnlikely
  3931  	b.SetControl(cmp)
  3932  	b.AddEdgeTo(grow)
  3933  	b.AddEdgeTo(assign)
  3934  
  3935  	// If the result of the append does not escape, we can use
  3936  	// a stack-allocated backing store if len is small enough.
  3937  	// A stack-allocated backing store could be used at every
  3938  	// append that qualifies, but we limit it in some cases to
  3939  	// avoid wasted code and stack space.
  3940  	//
  3941  	// Note that we have two different strategies.
  3942  	// 1. The standard strategy is just to allocate the full
  3943  	//    backing store at the first append.
  3944  	// 2. An alternate strategy is used when
  3945  	//        a. The backing store eventually escapes via move2heap
  3946  	//    and b. The capacity is used somehow
  3947  	//    In this case, we don't want to just allocate
  3948  	//    the full buffer at the first append, because when
  3949  	//    we move2heap the buffer to the heap when it escapes,
  3950  	//    we might end up wasting memory because we can't
  3951  	//    change the capacity.
  3952  	//    So in this case we use growsliceBuf to reuse the buffer
  3953  	//    and walk one step up the size class ladder each time.
  3954  	//
  3955  	// TODO: handle ... append case? Currently we handle only
  3956  	// a fixed number of appended elements.
  3957  	var info *backingStoreInfo
  3958  	if !inplace {
  3959  		info = s.getBackingStoreInfoForAppend(n)
  3960  	}
  3961  
  3962  	if !inplace && info != nil && !n.UseBuf && !info.usedStatic {
  3963  		// if l <= K {
  3964  		//   if !used {
  3965  		//     if oldLen == 0 {
  3966  		//       var store [K]T
  3967  		//       s = store[:l:K]
  3968  		//       used = true
  3969  		//     }
  3970  		//   }
  3971  		// }
  3972  		// ... if we didn't use the stack backing store, call growslice ...
  3973  		//
  3974  		// oldLen==0 is not strictly necessary, but requiring it means
  3975  		// we don't have to worry about copying existing elements.
  3976  		// Allowing oldLen>0 would add complication. Worth it? I would guess not.
  3977  		//
  3978  		// TODO: instead of the used boolean, we could insist that this only applies
  3979  		// to monotonic slices, those which once they have >0 entries never go back
  3980  		// to 0 entries. Then oldLen==0 is enough.
  3981  		//
  3982  		// We also do this for append(x, ...) once for every x.
  3983  		// It is ok to do it more often, but it is probably helpful only for
  3984  		// the first instance. TODO: this could use more tuning. Using ir.Node
  3985  		// as the key works for *ir.Name instances but probably nothing else.
  3986  		info.usedStatic = true
  3987  		// TODO: unset usedStatic somehow?
  3988  
  3989  		usedTestBlock := s.f.NewBlock(block.BlockPlain)
  3990  		oldLenTestBlock := s.f.NewBlock(block.BlockPlain)
  3991  		bodyBlock := s.f.NewBlock(block.BlockPlain)
  3992  		growSlice := s.f.NewBlock(block.BlockPlain)
  3993  		tInt := types.Types[types.TINT]
  3994  		tBool := types.Types[types.TBOOL]
  3995  
  3996  		// if l <= K
  3997  		s.startBlock(grow)
  3998  		kTest := s.newValue2(s.ssaOp(ir.OLE, tInt), tBool, l, s.constInt(tInt, info.K))
  3999  		b := s.endBlock()
  4000  		b.Kind = block.BlockIf
  4001  		b.SetControl(kTest)
  4002  		b.AddEdgeTo(usedTestBlock)
  4003  		b.AddEdgeTo(growSlice)
  4004  		b.Likely = ssa.BranchLikely
  4005  
  4006  		// if !used
  4007  		s.startBlock(usedTestBlock)
  4008  		usedTest := s.newValue1(ssa.OpNot, tBool, s.expr(info.used))
  4009  		b = s.endBlock()
  4010  		b.Kind = block.BlockIf
  4011  		b.SetControl(usedTest)
  4012  		b.AddEdgeTo(oldLenTestBlock)
  4013  		b.AddEdgeTo(growSlice)
  4014  		b.Likely = ssa.BranchLikely
  4015  
  4016  		// if oldLen == 0
  4017  		s.startBlock(oldLenTestBlock)
  4018  		oldLenTest := s.newValue2(s.ssaOp(ir.OEQ, tInt), tBool, oldLen, s.constInt(tInt, 0))
  4019  		b = s.endBlock()
  4020  		b.Kind = block.BlockIf
  4021  		b.SetControl(oldLenTest)
  4022  		b.AddEdgeTo(bodyBlock)
  4023  		b.AddEdgeTo(growSlice)
  4024  		b.Likely = ssa.BranchLikely
  4025  
  4026  		// var store struct { _ [0]uintptr; arr [K]T }
  4027  		s.startBlock(bodyBlock)
  4028  		if et.HasPointers() {
  4029  			s.vars[memVar] = s.newValue1A(ssa.OpVarDef, types.TypeMem, info.store, s.mem())
  4030  		}
  4031  		addr := s.addr(info.store)
  4032  		s.zero(info.store.Type(), addr)
  4033  
  4034  		// s = store.arr[:l:K]
  4035  		s.vars[ptrVar] = addr
  4036  		s.vars[lenVar] = l // nargs would also be ok because of the oldLen==0 test.
  4037  		s.vars[capVar] = s.constInt(tInt, info.K)
  4038  
  4039  		// used = true
  4040  		s.assign(info.used, s.constBool(true), false, 0)
  4041  		b = s.endBlock()
  4042  		b.AddEdgeTo(assign)
  4043  
  4044  		// New block to use for growslice call.
  4045  		grow = growSlice
  4046  	}
  4047  
  4048  	// Call growslice
  4049  	s.startBlock(grow)
  4050  	taddr := s.expr(n.Fun)
  4051  	var r []*ssa.Value
  4052  	if info != nil && n.UseBuf {
  4053  		// Use stack-allocated buffer as backing store, if we can.
  4054  		if et.HasPointers() && !info.usedStatic {
  4055  			// Initialize in the function header. Not the best place,
  4056  			// but it makes sure we don't scan this area before it is
  4057  			// initialized.
  4058  			mem := s.defvars[s.f.Entry.ID][memVar]
  4059  			mem = s.f.Entry.NewValue1A(n.Pos(), ssa.OpVarDef, types.TypeMem, info.store, mem)
  4060  			addr := s.f.Entry.NewValue2A(n.Pos(), ssa.OpLocalAddr, types.NewPtr(info.store.Type()), info.store, s.sp, mem)
  4061  			mem = s.f.Entry.NewValue2I(n.Pos(), ssa.OpZero, types.TypeMem, info.store.Type().Size(), addr, mem)
  4062  			mem.Aux = info.store.Type()
  4063  			s.defvars[s.f.Entry.ID][memVar] = mem
  4064  			info.usedStatic = true
  4065  		}
  4066  		fn := ir.Syms.GrowsliceBuf
  4067  		if goexperiment.RuntimeFreegc && n.AppendNoAlias && !et.HasPointers() {
  4068  			// The append is for a non-aliased slice where the runtime knows how to free
  4069  			// the old logically dead backing store after growth.
  4070  			// TODO(thepudds): for now, we only use the NoAlias version for element types
  4071  			// without pointers while waiting on additional runtime support (CL 698515).
  4072  			fn = ir.Syms.GrowsliceBufNoAlias
  4073  		}
  4074  		r = s.rtcall(fn, true, []*types.Type{n.Type()}, p, l, c, nargs, taddr, s.addr(info.store), s.constInt(types.Types[types.TINT], info.K))
  4075  	} else {
  4076  		fn := ir.Syms.Growslice
  4077  		if goexperiment.RuntimeFreegc && n.AppendNoAlias && !et.HasPointers() {
  4078  			// The append is for a non-aliased slice where the runtime knows how to free
  4079  			// the old logically dead backing store after growth.
  4080  			// TODO(thepudds): for now, we only use the NoAlias version for element types
  4081  			// without pointers while waiting on additional runtime support (CL 698515).
  4082  			fn = ir.Syms.GrowsliceNoAlias
  4083  		}
  4084  		r = s.rtcall(fn, true, []*types.Type{n.Type()}, p, l, c, nargs, taddr)
  4085  	}
  4086  
  4087  	// Decompose output slice
  4088  	p = s.newValue1(ssa.OpSlicePtr, pt, r[0])
  4089  	l = s.newValue1(ssa.OpSliceLen, types.Types[types.TINT], r[0])
  4090  	c = s.newValue1(ssa.OpSliceCap, types.Types[types.TINT], r[0])
  4091  
  4092  	s.vars[ptrVar] = p
  4093  	s.vars[lenVar] = l
  4094  	s.vars[capVar] = c
  4095  	if inplace {
  4096  		if sn.Op() == ir.ONAME {
  4097  			sn := sn.(*ir.Name)
  4098  			if sn.Class != ir.PEXTERN {
  4099  				// Tell liveness we're about to build a new slice
  4100  				s.vars[memVar] = s.newValue1A(ssa.OpVarDef, types.TypeMem, sn, s.mem())
  4101  			}
  4102  		}
  4103  		capaddr := s.newValue1I(ssa.OpOffPtr, s.f.Config.Types.IntPtr, types.SliceCapOffset, addr)
  4104  		s.store(types.Types[types.TINT], capaddr, c)
  4105  		s.store(pt, addr, p)
  4106  	}
  4107  
  4108  	b = s.endBlock()
  4109  	b.AddEdgeTo(assign)
  4110  
  4111  	// assign new elements to slots
  4112  	s.startBlock(assign)
  4113  	p = s.variable(ptrVar, pt)                      // generates phi for ptr
  4114  	l = s.variable(lenVar, types.Types[types.TINT]) // generates phi for len
  4115  	if !inplace {
  4116  		c = s.variable(capVar, types.Types[types.TINT]) // generates phi for cap
  4117  	}
  4118  
  4119  	if inplace {
  4120  		// Update length in place.
  4121  		// We have to wait until here to make sure growslice succeeded.
  4122  		lenaddr := s.newValue1I(ssa.OpOffPtr, s.f.Config.Types.IntPtr, types.SliceLenOffset, addr)
  4123  		s.store(types.Types[types.TINT], lenaddr, l)
  4124  	}
  4125  
  4126  	// Evaluate args
  4127  	type argRec struct {
  4128  		// if store is true, we're appending the value v.  If false, we're appending the
  4129  		// value at *v.
  4130  		v     *ssa.Value
  4131  		store bool
  4132  	}
  4133  	args := make([]argRec, 0, len(n.Args[1:]))
  4134  	for _, n := range n.Args[1:] {
  4135  		if ssa.CanSSA(n.Type()) {
  4136  			args = append(args, argRec{v: s.expr(n), store: true})
  4137  		} else {
  4138  			v := s.addr(n)
  4139  			args = append(args, argRec{v: v})
  4140  		}
  4141  	}
  4142  
  4143  	// Write args into slice.
  4144  	oldLen = s.newValue2(s.ssaOp(ir.OSUB, types.Types[types.TINT]), types.Types[types.TINT], l, nargs)
  4145  	p2 := s.newValue2(ssa.OpPtrIndex, pt, p, oldLen)
  4146  	for i, arg := range args {
  4147  		addr := s.newValue2(ssa.OpPtrIndex, pt, p2, s.constInt(types.Types[types.TINT], int64(i)))
  4148  		if arg.store {
  4149  			s.storeType(et, addr, arg.v, 0, true)
  4150  		} else {
  4151  			s.move(et, addr, arg.v)
  4152  		}
  4153  	}
  4154  
  4155  	// The following deletions have no practical effect at this time
  4156  	// because state.vars has been reset by the preceding state.startBlock.
  4157  	// They only enforce the fact that these variables are no longer need in
  4158  	// the current scope.
  4159  	delete(s.vars, ptrVar)
  4160  	delete(s.vars, lenVar)
  4161  	if !inplace {
  4162  		delete(s.vars, capVar)
  4163  	}
  4164  
  4165  	// make result
  4166  	if inplace {
  4167  		return nil
  4168  	}
  4169  	return s.newValue3(ssa.OpSliceMake, n.Type(), p, l, c)
  4170  }
  4171  
  4172  func (s *state) move2heap(n *ir.MoveToHeapExpr) *ssa.Value {
  4173  	// s := n.Slice
  4174  	// if s.ptr points to current stack frame {
  4175  	//     s2 := make([]T, s.len, s.cap)
  4176  	//     copy(s2[:cap], s[:cap])
  4177  	//     s = s2
  4178  	// }
  4179  	// return s
  4180  
  4181  	slice := s.expr(n.Slice)
  4182  	et := slice.Type.Elem()
  4183  	pt := types.NewPtr(et)
  4184  
  4185  	info := s.getBackingStoreInfo(n)
  4186  	if info == nil {
  4187  		// Backing store will never be stack allocated, so
  4188  		// move2heap is a no-op.
  4189  		return slice
  4190  	}
  4191  
  4192  	// Decomposse input slice.
  4193  	p := s.newValue1(ssa.OpSlicePtr, pt, slice)
  4194  	l := s.newValue1(ssa.OpSliceLen, types.Types[types.TINT], slice)
  4195  	c := s.newValue1(ssa.OpSliceCap, types.Types[types.TINT], slice)
  4196  
  4197  	moveBlock := s.f.NewBlock(block.BlockPlain)
  4198  	mergeBlock := s.f.NewBlock(block.BlockPlain)
  4199  
  4200  	s.vars[ptrVar] = p
  4201  	s.vars[lenVar] = l
  4202  	s.vars[capVar] = c
  4203  
  4204  	// Decide if we need to move the slice backing store.
  4205  	// It needs to be moved if it is currently on the stack.
  4206  	sub := ssa.OpSub64
  4207  	less := ssa.OpLess64U
  4208  	if s.config.PtrSize == 4 {
  4209  		sub = ssa.OpSub32
  4210  		less = ssa.OpLess32U
  4211  	}
  4212  	callerSP := s.newValue1(ssa.OpGetCallerSP, types.Types[types.TUINTPTR], s.mem())
  4213  	frameSize := s.newValue2(sub, types.Types[types.TUINTPTR], callerSP, s.sp)
  4214  	pInt := s.newValue2(ssa.OpConvert, types.Types[types.TUINTPTR], p, s.mem())
  4215  	off := s.newValue2(sub, types.Types[types.TUINTPTR], pInt, s.sp)
  4216  	cond := s.newValue2(less, types.Types[types.TBOOL], off, frameSize)
  4217  
  4218  	b := s.endBlock()
  4219  	b.Kind = block.BlockIf
  4220  	b.Likely = ssa.BranchUnlikely // fast path is to not have to call into runtime
  4221  	b.SetControl(cond)
  4222  	b.AddEdgeTo(moveBlock)
  4223  	b.AddEdgeTo(mergeBlock)
  4224  
  4225  	// Move the slice to heap
  4226  	s.startBlock(moveBlock)
  4227  	var newSlice *ssa.Value
  4228  	if et.HasPointers() {
  4229  		typ := s.expr(n.RType)
  4230  		if n.PreserveCapacity {
  4231  			newSlice = s.rtcall(ir.Syms.MoveSlice, true, []*types.Type{slice.Type}, typ, p, l, c)[0]
  4232  		} else {
  4233  			newSlice = s.rtcall(ir.Syms.MoveSliceNoCap, true, []*types.Type{slice.Type}, typ, p, l)[0]
  4234  		}
  4235  	} else {
  4236  		elemSize := s.constInt(types.Types[types.TUINTPTR], et.Size())
  4237  		if n.PreserveCapacity {
  4238  			newSlice = s.rtcall(ir.Syms.MoveSliceNoScan, true, []*types.Type{slice.Type}, elemSize, p, l, c)[0]
  4239  		} else {
  4240  			newSlice = s.rtcall(ir.Syms.MoveSliceNoCapNoScan, true, []*types.Type{slice.Type}, elemSize, p, l)[0]
  4241  		}
  4242  	}
  4243  	// Decompose output slice
  4244  	s.vars[ptrVar] = s.newValue1(ssa.OpSlicePtr, pt, newSlice)
  4245  	s.vars[lenVar] = s.newValue1(ssa.OpSliceLen, types.Types[types.TINT], newSlice)
  4246  	s.vars[capVar] = s.newValue1(ssa.OpSliceCap, types.Types[types.TINT], newSlice)
  4247  	b = s.endBlock()
  4248  	b.AddEdgeTo(mergeBlock)
  4249  
  4250  	// Merge fast path (no moving) and slow path (moved)
  4251  	s.startBlock(mergeBlock)
  4252  	p = s.variable(ptrVar, pt)                      // generates phi for ptr
  4253  	l = s.variable(lenVar, types.Types[types.TINT]) // generates phi for len
  4254  	c = s.variable(capVar, types.Types[types.TINT]) // generates phi for cap
  4255  	delete(s.vars, ptrVar)
  4256  	delete(s.vars, lenVar)
  4257  	delete(s.vars, capVar)
  4258  	return s.newValue3(ssa.OpSliceMake, slice.Type, p, l, c)
  4259  }
  4260  
  4261  // minMax converts an OMIN/OMAX builtin call into SSA.
  4262  func (s *state) minMax(n *ir.CallExpr) *ssa.Value {
  4263  	// The OMIN/OMAX builtin is variadic, but its semantics are
  4264  	// equivalent to left-folding a binary min/max operation across the
  4265  	// arguments list.
  4266  	fold := func(op func(x, a *ssa.Value) *ssa.Value) *ssa.Value {
  4267  		x := s.expr(n.Args[0])
  4268  		for _, arg := range n.Args[1:] {
  4269  			x = op(x, s.expr(arg))
  4270  		}
  4271  		return x
  4272  	}
  4273  
  4274  	typ := n.Type()
  4275  
  4276  	if typ.IsFloat() || typ.IsString() {
  4277  		// min/max semantics for floats are tricky because of NaNs and
  4278  		// negative zero. Some architectures have instructions which
  4279  		// we can use to generate the right result. For others we must
  4280  		// call into the runtime instead.
  4281  		//
  4282  		// Strings are conceptually simpler, but we currently desugar
  4283  		// string comparisons during walk, not ssagen.
  4284  
  4285  		if typ.IsFloat() {
  4286  			hasIntrinsic := false
  4287  			switch Arch.LinkArch.Family {
  4288  			case sys.AMD64, sys.ARM64, sys.Loong64, sys.RISCV64, sys.S390X:
  4289  				hasIntrinsic = true
  4290  			case sys.PPC64:
  4291  				hasIntrinsic = buildcfg.GOPPC64 >= 9
  4292  			}
  4293  
  4294  			if hasIntrinsic {
  4295  				var op ssa.Op
  4296  				switch {
  4297  				case typ.Kind() == types.TFLOAT64 && n.Op() == ir.OMIN:
  4298  					op = ssa.OpMin64F
  4299  				case typ.Kind() == types.TFLOAT64 && n.Op() == ir.OMAX:
  4300  					op = ssa.OpMax64F
  4301  				case typ.Kind() == types.TFLOAT32 && n.Op() == ir.OMIN:
  4302  					op = ssa.OpMin32F
  4303  				case typ.Kind() == types.TFLOAT32 && n.Op() == ir.OMAX:
  4304  					op = ssa.OpMax32F
  4305  				}
  4306  				return fold(func(x, a *ssa.Value) *ssa.Value {
  4307  					return s.newValue2(op, typ, x, a)
  4308  				})
  4309  			}
  4310  		}
  4311  		var name string
  4312  		switch typ.Kind() {
  4313  		case types.TFLOAT32:
  4314  			switch n.Op() {
  4315  			case ir.OMIN:
  4316  				name = "fmin32"
  4317  			case ir.OMAX:
  4318  				name = "fmax32"
  4319  			}
  4320  		case types.TFLOAT64:
  4321  			switch n.Op() {
  4322  			case ir.OMIN:
  4323  				name = "fmin64"
  4324  			case ir.OMAX:
  4325  				name = "fmax64"
  4326  			}
  4327  		case types.TSTRING:
  4328  			switch n.Op() {
  4329  			case ir.OMIN:
  4330  				name = "strmin"
  4331  			case ir.OMAX:
  4332  				name = "strmax"
  4333  			}
  4334  		}
  4335  		fn := typecheck.LookupRuntimeFunc(name)
  4336  
  4337  		return fold(func(x, a *ssa.Value) *ssa.Value {
  4338  			return s.rtcall(fn, true, []*types.Type{typ}, x, a)[0]
  4339  		})
  4340  	}
  4341  
  4342  	if typ.IsInteger() {
  4343  		if Arch.LinkArch.Family == sys.RISCV64 && buildcfg.GORISCV64 >= 22 && typ.Size() == 8 {
  4344  			var op ssa.Op
  4345  			switch {
  4346  			case typ.IsSigned() && n.Op() == ir.OMIN:
  4347  				op = ssa.OpMin64
  4348  			case typ.IsSigned() && n.Op() == ir.OMAX:
  4349  				op = ssa.OpMax64
  4350  			case typ.IsUnsigned() && n.Op() == ir.OMIN:
  4351  				op = ssa.OpMin64u
  4352  			case typ.IsUnsigned() && n.Op() == ir.OMAX:
  4353  				op = ssa.OpMax64u
  4354  			}
  4355  			return fold(func(x, a *ssa.Value) *ssa.Value {
  4356  				return s.newValue2(op, typ, x, a)
  4357  			})
  4358  		}
  4359  	}
  4360  
  4361  	lt := s.ssaOp(ir.OLT, typ)
  4362  
  4363  	return fold(func(x, a *ssa.Value) *ssa.Value {
  4364  		switch n.Op() {
  4365  		case ir.OMIN:
  4366  			// a < x ? a : x
  4367  			return s.ternary(s.newValue2(lt, types.Types[types.TBOOL], a, x), a, x)
  4368  		case ir.OMAX:
  4369  			// x < a ? a : x
  4370  			return s.ternary(s.newValue2(lt, types.Types[types.TBOOL], x, a), a, x)
  4371  		}
  4372  		panic("unreachable")
  4373  	})
  4374  }
  4375  
  4376  // ternary emits code to evaluate cond ? x : y.
  4377  func (s *state) ternary(cond, x, y *ssa.Value) *ssa.Value {
  4378  	// Note that we need a new ternaryVar each time (unlike okVar where we can
  4379  	// reuse the variable) because it might have a different type every time.
  4380  	ternaryVar := ssaMarker("ternary")
  4381  
  4382  	bThen := s.f.NewBlock(block.BlockPlain)
  4383  	bElse := s.f.NewBlock(block.BlockPlain)
  4384  	bEnd := s.f.NewBlock(block.BlockPlain)
  4385  
  4386  	b := s.endBlock()
  4387  	b.Kind = block.BlockIf
  4388  	b.SetControl(cond)
  4389  	b.AddEdgeTo(bThen)
  4390  	b.AddEdgeTo(bElse)
  4391  
  4392  	s.startBlock(bThen)
  4393  	s.vars[ternaryVar] = x
  4394  	s.endBlock().AddEdgeTo(bEnd)
  4395  
  4396  	s.startBlock(bElse)
  4397  	s.vars[ternaryVar] = y
  4398  	s.endBlock().AddEdgeTo(bEnd)
  4399  
  4400  	s.startBlock(bEnd)
  4401  	r := s.variable(ternaryVar, x.Type)
  4402  	delete(s.vars, ternaryVar)
  4403  	return r
  4404  }
  4405  
  4406  // condBranch evaluates the boolean expression cond and branches to yes
  4407  // if cond is true and no if cond is false.
  4408  // This function is intended to handle && and || better than just calling
  4409  // s.expr(cond) and branching on the result.
  4410  func (s *state) condBranch(cond ir.Node, yes, no *ssa.Block, likely int8) {
  4411  	switch cond.Op() {
  4412  	case ir.OANDAND:
  4413  		cond := cond.(*ir.LogicalExpr)
  4414  		mid := s.f.NewBlock(block.BlockPlain)
  4415  		s.stmtList(cond.Init())
  4416  		s.condBranch(cond.X, mid, no, max(likely, 0))
  4417  		s.startBlock(mid)
  4418  		s.condBranch(cond.Y, yes, no, likely)
  4419  		return
  4420  		// Note: if likely==1, then both recursive calls pass 1.
  4421  		// If likely==-1, then we don't have enough information to decide
  4422  		// whether the first branch is likely or not. So we pass 0 for
  4423  		// the likeliness of the first branch.
  4424  		// TODO: have the frontend give us branch prediction hints for
  4425  		// OANDAND and OOROR nodes (if it ever has such info).
  4426  	case ir.OOROR:
  4427  		cond := cond.(*ir.LogicalExpr)
  4428  		mid := s.f.NewBlock(block.BlockPlain)
  4429  		s.stmtList(cond.Init())
  4430  		s.condBranch(cond.X, yes, mid, min(likely, 0))
  4431  		s.startBlock(mid)
  4432  		s.condBranch(cond.Y, yes, no, likely)
  4433  		return
  4434  		// Note: if likely==-1, then both recursive calls pass -1.
  4435  		// If likely==1, then we don't have enough info to decide
  4436  		// the likelihood of the first branch.
  4437  	case ir.ONOT:
  4438  		cond := cond.(*ir.UnaryExpr)
  4439  		s.stmtList(cond.Init())
  4440  		s.condBranch(cond.X, no, yes, -likely)
  4441  		return
  4442  	case ir.OCONVNOP:
  4443  		cond := cond.(*ir.ConvExpr)
  4444  		s.stmtList(cond.Init())
  4445  		s.condBranch(cond.X, yes, no, likely)
  4446  		return
  4447  	}
  4448  	c := s.expr(cond)
  4449  	b := s.endBlock()
  4450  	b.Kind = block.BlockIf
  4451  	b.SetControl(c)
  4452  	b.Likely = ssa.BranchPrediction(likely) // gc and ssa both use -1/0/+1 for likeliness
  4453  	b.AddEdgeTo(yes)
  4454  	b.AddEdgeTo(no)
  4455  }
  4456  
  4457  type skipMask uint8
  4458  
  4459  const (
  4460  	skipPtr skipMask = 1 << iota
  4461  	skipLen
  4462  	skipCap
  4463  )
  4464  
  4465  // assign does left = right.
  4466  // Right has already been evaluated to ssa, left has not.
  4467  // If deref is true, then we do left = *right instead (and right has already been nil-checked).
  4468  // If deref is true and right == nil, just do left = 0.
  4469  // skip indicates assignments (at the top level) that can be avoided.
  4470  // mayOverlap indicates whether left&right might partially overlap in memory. Default is false.
  4471  func (s *state) assign(left ir.Node, right *ssa.Value, deref bool, skip skipMask) {
  4472  	s.assignWhichMayOverlap(left, right, deref, skip, false)
  4473  }
  4474  func (s *state) assignWhichMayOverlap(left ir.Node, right *ssa.Value, deref bool, skip skipMask, mayOverlap bool) {
  4475  	if left.Op() == ir.ONAME && ir.IsBlank(left) {
  4476  		return
  4477  	}
  4478  	t := left.Type()
  4479  	types.CalcSize(t)
  4480  	if s.canSSA(left) {
  4481  		if deref {
  4482  			s.Fatalf("can SSA LHS %v but not RHS %s", left, right)
  4483  		}
  4484  		if left.Op() == ir.ODOT {
  4485  			// We're assigning to a field of an ssa-able value.
  4486  			// We need to build a new structure with the new value for the
  4487  			// field we're assigning and the old values for the other fields.
  4488  			// For instance:
  4489  			//   type T struct {a, b, c int}
  4490  			//   var T x
  4491  			//   x.b = 5
  4492  			// For the x.b = 5 assignment we want to generate x = T{x.a, 5, x.c}
  4493  
  4494  			// Grab information about the structure type.
  4495  			left := left.(*ir.SelectorExpr)
  4496  			t := left.X.Type()
  4497  			nf := t.NumFields()
  4498  			idx := fieldIdx(left)
  4499  
  4500  			// Grab old value of structure.
  4501  			old := s.expr(left.X)
  4502  
  4503  			if left.Type().Size() == 0 {
  4504  				// Nothing to do when assigning zero-sized things.
  4505  				return
  4506  			}
  4507  
  4508  			// Make new structure.
  4509  			new := s.newValue0(ssa.OpStructMake, t)
  4510  
  4511  			// Add fields as args.
  4512  			for i := 0; i < nf; i++ {
  4513  				if i == idx {
  4514  					new.AddArg(right)
  4515  				} else {
  4516  					new.AddArg(s.newValue1I(ssa.OpStructSelect, t.FieldType(i), int64(i), old))
  4517  				}
  4518  			}
  4519  
  4520  			// Recursively assign the new value we've made to the base of the dot op.
  4521  			s.assign(left.X, new, false, 0)
  4522  			// TODO: do we need to update named values here?
  4523  			return
  4524  		}
  4525  		if left.Op() == ir.OINDEX && left.(*ir.IndexExpr).X.Type().IsArray() {
  4526  			left := left.(*ir.IndexExpr)
  4527  			s.pushLine(left.Pos())
  4528  			defer s.popLine()
  4529  			// We're assigning to an element of an ssa-able array.
  4530  			// a[i] = v
  4531  			t := left.X.Type()
  4532  			n := t.NumElem()
  4533  
  4534  			i := s.expr(left.Index) // index
  4535  			if n == 0 {
  4536  				_ = s.expr(left.X) // Evaluating left.X for any side-effects.
  4537  				// The bounds check must fail.  Might as well
  4538  				// ignore the actual index and just use zeros.
  4539  				z := s.constInt(types.Types[types.TINT], 0)
  4540  				s.boundsCheck(z, z, ssa.BoundsIndex, false)
  4541  				return
  4542  			}
  4543  			if t.Size() == 0 {
  4544  				_ = s.expr(left.X) // Evaluating left.X for any side-effects.
  4545  				// Generate bounds check for left, since this can happen
  4546  				// for 0-size assignment case, see issue #79236.
  4547  				len := s.constInt(types.Types[types.TINT], n)
  4548  				s.boundsCheck(i, len, ssa.BoundsIndex, false)
  4549  				return
  4550  			}
  4551  			if n != 1 {
  4552  				// This can happen in weird, always-panics cases, like:
  4553  				//     var x [0][2]int
  4554  				//     x[i][j] = 5
  4555  				// We know it always panics because the LHS is ssa-able,
  4556  				// and arrays of length > 1 can't be ssa-able unless
  4557  				// they are somewhere inside an outer [0].
  4558  				// We can ignore the actual assignment, it is dynamically
  4559  				// unreachable. See issue 77635.
  4560  				// Still, evaluating left.X for any side-effects.
  4561  				_ = s.expr(left.X)
  4562  				return
  4563  			}
  4564  
  4565  			// Rewrite to a = [1]{v}
  4566  			len := s.constInt(types.Types[types.TINT], 1)
  4567  			s.boundsCheck(i, len, ssa.BoundsIndex, false) // checks i == 0
  4568  			v := s.newValue1(ssa.OpArrayMake1, t, right)
  4569  			s.assign(left.X, v, false, 0)
  4570  			return
  4571  		}
  4572  		left := left.(*ir.Name)
  4573  		// Update variable assignment.
  4574  		s.vars[left] = right
  4575  		s.addNamedValue(left, right)
  4576  		return
  4577  	}
  4578  
  4579  	// If this assignment clobbers an entire local variable, then emit
  4580  	// OpVarDef so liveness analysis knows the variable is redefined.
  4581  	if base, ok := clobberBase(left).(*ir.Name); ok && base.OnStack() && skip == 0 && (t.HasPointers() || ssa.IsMergeCandidate(base)) {
  4582  		s.vars[memVar] = s.newValue1Apos(ssa.OpVarDef, types.TypeMem, base, s.mem(), !ir.IsAutoTmp(base))
  4583  	}
  4584  
  4585  	// Left is not ssa-able. Compute its address.
  4586  	addr := s.addr(left)
  4587  	if ir.IsReflectHeaderDataField(left) {
  4588  		// Package unsafe's documentation says storing pointers into
  4589  		// reflect.SliceHeader and reflect.StringHeader's Data fields
  4590  		// is valid, even though they have type uintptr (#19168).
  4591  		// Mark it pointer type to signal the writebarrier pass to
  4592  		// insert a write barrier.
  4593  		t = types.Types[types.TUNSAFEPTR]
  4594  	}
  4595  	if deref {
  4596  		// Treat as a mem->mem move.
  4597  		if right == nil {
  4598  			s.zero(t, addr)
  4599  		} else {
  4600  			s.moveWhichMayOverlap(t, addr, right, mayOverlap)
  4601  		}
  4602  		return
  4603  	}
  4604  	// Treat as a store.
  4605  	s.storeType(t, addr, right, skip, !ir.IsAutoTmp(left))
  4606  }
  4607  
  4608  // zeroVal returns the zero value for type t.
  4609  func (s *state) zeroVal(t *types.Type) *ssa.Value {
  4610  	if t.Size() == 0 {
  4611  		return s.entryNewValue0(ssa.OpEmpty, t)
  4612  	}
  4613  	switch {
  4614  	case t.IsInteger():
  4615  		switch t.Size() {
  4616  		case 1:
  4617  			return s.constInt8(t, 0)
  4618  		case 2:
  4619  			return s.constInt16(t, 0)
  4620  		case 4:
  4621  			return s.constInt32(t, 0)
  4622  		case 8:
  4623  			return s.constInt64(t, 0)
  4624  		default:
  4625  			s.Fatalf("bad sized integer type %v", t)
  4626  		}
  4627  	case t.IsFloat():
  4628  		switch t.Size() {
  4629  		case 4:
  4630  			return s.constFloat32(t, 0)
  4631  		case 8:
  4632  			return s.constFloat64(t, 0)
  4633  		default:
  4634  			s.Fatalf("bad sized float type %v", t)
  4635  		}
  4636  	case t.IsComplex():
  4637  		switch t.Size() {
  4638  		case 8:
  4639  			z := s.constFloat32(types.Types[types.TFLOAT32], 0)
  4640  			return s.entryNewValue2(ssa.OpComplexMake, t, z, z)
  4641  		case 16:
  4642  			z := s.constFloat64(types.Types[types.TFLOAT64], 0)
  4643  			return s.entryNewValue2(ssa.OpComplexMake, t, z, z)
  4644  		default:
  4645  			s.Fatalf("bad sized complex type %v", t)
  4646  		}
  4647  
  4648  	case t.IsString():
  4649  		return s.constEmptyString(t)
  4650  	case t.IsPtrShaped():
  4651  		return s.constNil(t)
  4652  	case t.IsBoolean():
  4653  		return s.constBool(false)
  4654  	case t.IsInterface():
  4655  		return s.constInterface(t)
  4656  	case t.IsSlice():
  4657  		return s.constSlice(t)
  4658  	case isStructNotSIMD(t):
  4659  		n := t.NumFields()
  4660  		v := s.entryNewValue0(ssa.OpStructMake, t)
  4661  		for i := 0; i < n; i++ {
  4662  			v.AddArg(s.zeroVal(t.FieldType(i)))
  4663  		}
  4664  		return v
  4665  	case t.IsArray() && t.NumElem() == 1:
  4666  		return s.entryNewValue1(ssa.OpArrayMake1, t, s.zeroVal(t.Elem()))
  4667  	case t.IsSIMD():
  4668  		return s.newValue0(ssa.OpZeroSIMD, t)
  4669  	}
  4670  	s.Fatalf("zero for type %v not implemented", t)
  4671  	return nil
  4672  }
  4673  
  4674  type callKind int8
  4675  
  4676  const (
  4677  	callNormal callKind = iota
  4678  	callDefer
  4679  	callDeferStack
  4680  	callGo
  4681  	callTail
  4682  )
  4683  
  4684  type sfRtCallDef struct {
  4685  	rtfn  *obj.LSym
  4686  	rtype types.Kind
  4687  }
  4688  
  4689  var softFloatOps map[ssa.Op]sfRtCallDef
  4690  
  4691  func softfloatInit() {
  4692  	// Some of these operations get transformed by sfcall.
  4693  	softFloatOps = map[ssa.Op]sfRtCallDef{
  4694  		ssa.OpAdd32F: {typecheck.LookupRuntimeFunc("fadd32"), types.TFLOAT32},
  4695  		ssa.OpAdd64F: {typecheck.LookupRuntimeFunc("fadd64"), types.TFLOAT64},
  4696  		ssa.OpSub32F: {typecheck.LookupRuntimeFunc("fadd32"), types.TFLOAT32},
  4697  		ssa.OpSub64F: {typecheck.LookupRuntimeFunc("fadd64"), types.TFLOAT64},
  4698  		ssa.OpMul32F: {typecheck.LookupRuntimeFunc("fmul32"), types.TFLOAT32},
  4699  		ssa.OpMul64F: {typecheck.LookupRuntimeFunc("fmul64"), types.TFLOAT64},
  4700  		ssa.OpDiv32F: {typecheck.LookupRuntimeFunc("fdiv32"), types.TFLOAT32},
  4701  		ssa.OpDiv64F: {typecheck.LookupRuntimeFunc("fdiv64"), types.TFLOAT64},
  4702  
  4703  		ssa.OpEq64F:   {typecheck.LookupRuntimeFunc("feq64"), types.TBOOL},
  4704  		ssa.OpEq32F:   {typecheck.LookupRuntimeFunc("feq32"), types.TBOOL},
  4705  		ssa.OpNeq64F:  {typecheck.LookupRuntimeFunc("feq64"), types.TBOOL},
  4706  		ssa.OpNeq32F:  {typecheck.LookupRuntimeFunc("feq32"), types.TBOOL},
  4707  		ssa.OpLess64F: {typecheck.LookupRuntimeFunc("fgt64"), types.TBOOL},
  4708  		ssa.OpLess32F: {typecheck.LookupRuntimeFunc("fgt32"), types.TBOOL},
  4709  		ssa.OpLeq64F:  {typecheck.LookupRuntimeFunc("fge64"), types.TBOOL},
  4710  		ssa.OpLeq32F:  {typecheck.LookupRuntimeFunc("fge32"), types.TBOOL},
  4711  
  4712  		ssa.OpCvt32to32F:  {typecheck.LookupRuntimeFunc("fint32to32"), types.TFLOAT32},
  4713  		ssa.OpCvt32Fto32:  {typecheck.LookupRuntimeFunc("f32toint32"), types.TINT32},
  4714  		ssa.OpCvt64to32F:  {typecheck.LookupRuntimeFunc("fint64to32"), types.TFLOAT32},
  4715  		ssa.OpCvt32Fto64:  {typecheck.LookupRuntimeFunc("f32toint64"), types.TINT64},
  4716  		ssa.OpCvt64Uto32F: {typecheck.LookupRuntimeFunc("fuint64to32"), types.TFLOAT32},
  4717  		ssa.OpCvt32Fto64U: {typecheck.LookupRuntimeFunc("f32touint64"), types.TUINT64},
  4718  		ssa.OpCvt32to64F:  {typecheck.LookupRuntimeFunc("fint32to64"), types.TFLOAT64},
  4719  		ssa.OpCvt64Fto32:  {typecheck.LookupRuntimeFunc("f64toint32"), types.TINT32},
  4720  		ssa.OpCvt64to64F:  {typecheck.LookupRuntimeFunc("fint64to64"), types.TFLOAT64},
  4721  		ssa.OpCvt64Fto64:  {typecheck.LookupRuntimeFunc("f64toint64"), types.TINT64},
  4722  		ssa.OpCvt64Uto64F: {typecheck.LookupRuntimeFunc("fuint64to64"), types.TFLOAT64},
  4723  		ssa.OpCvt64Fto64U: {typecheck.LookupRuntimeFunc("f64touint64"), types.TUINT64},
  4724  		ssa.OpCvt32Fto64F: {typecheck.LookupRuntimeFunc("f32to64"), types.TFLOAT64},
  4725  		ssa.OpCvt64Fto32F: {typecheck.LookupRuntimeFunc("f64to32"), types.TFLOAT32},
  4726  	}
  4727  }
  4728  
  4729  // TODO: do not emit sfcall if operation can be optimized to constant in later
  4730  // opt phase
  4731  func (s *state) sfcall(op ssa.Op, args ...*ssa.Value) (*ssa.Value, bool) {
  4732  	f2i := func(t *types.Type) *types.Type {
  4733  		switch t.Kind() {
  4734  		case types.TFLOAT32:
  4735  			return types.Types[types.TUINT32]
  4736  		case types.TFLOAT64:
  4737  			return types.Types[types.TUINT64]
  4738  		}
  4739  		return t
  4740  	}
  4741  
  4742  	if callDef, ok := softFloatOps[op]; ok {
  4743  		switch op {
  4744  		case ssa.OpLess32F,
  4745  			ssa.OpLess64F,
  4746  			ssa.OpLeq32F,
  4747  			ssa.OpLeq64F:
  4748  			args[0], args[1] = args[1], args[0]
  4749  		case ssa.OpSub32F,
  4750  			ssa.OpSub64F:
  4751  			args[1] = s.newValue1(s.ssaOp(ir.ONEG, types.Types[callDef.rtype]), args[1].Type, args[1])
  4752  		}
  4753  
  4754  		// runtime functions take uints for floats and returns uints.
  4755  		// Convert to uints so we use the right calling convention.
  4756  		for i, a := range args {
  4757  			if a.Type.IsFloat() {
  4758  				args[i] = s.newValue1(ssa.OpCopy, f2i(a.Type), a)
  4759  			}
  4760  		}
  4761  
  4762  		rt := types.Types[callDef.rtype]
  4763  		result := s.rtcall(callDef.rtfn, true, []*types.Type{f2i(rt)}, args...)[0]
  4764  		if rt.IsFloat() {
  4765  			result = s.newValue1(ssa.OpCopy, rt, result)
  4766  		}
  4767  		if op == ssa.OpNeq32F || op == ssa.OpNeq64F {
  4768  			result = s.newValue1(ssa.OpNot, result.Type, result)
  4769  		}
  4770  		return result, true
  4771  	}
  4772  	return nil, false
  4773  }
  4774  
  4775  // split breaks up a tuple-typed value into its 2 parts.
  4776  func (s *state) split(v *ssa.Value) (*ssa.Value, *ssa.Value) {
  4777  	p0 := s.newValue1(ssa.OpSelect0, v.Type.FieldType(0), v)
  4778  	p1 := s.newValue1(ssa.OpSelect1, v.Type.FieldType(1), v)
  4779  	return p0, p1
  4780  }
  4781  
  4782  // intrinsicCall converts a call to a recognized intrinsic function into the intrinsic SSA operation.
  4783  func (s *state) intrinsicCall(n *ir.CallExpr) *ssa.Value {
  4784  	v := findIntrinsic(n.Fun.Sym())(s, n, s.intrinsicArgs(n))
  4785  	if ssaconfig.IntrinsicsDebug > 0 {
  4786  		x := v
  4787  		if x == nil {
  4788  			x = s.mem()
  4789  		}
  4790  		if x.Op == ssa.OpSelect0 || x.Op == ssa.OpSelect1 {
  4791  			x = x.Args[0]
  4792  		}
  4793  		base.WarnfAt(n.Pos(), "intrinsic substitution for %v with %s", n.Fun.Sym().Name, x.LongString())
  4794  	}
  4795  	return v
  4796  }
  4797  
  4798  // intrinsicArgs extracts args from n, evaluates them to SSA values, and returns them.
  4799  func (s *state) intrinsicArgs(n *ir.CallExpr) []*ssa.Value {
  4800  	args := make([]*ssa.Value, len(n.Args))
  4801  	for i, n := range n.Args {
  4802  		args[i] = s.expr(n)
  4803  	}
  4804  	return args
  4805  }
  4806  
  4807  // openDeferRecord adds code to evaluate and store the function for an open-code defer
  4808  // call, and records info about the defer, so we can generate proper code on the
  4809  // exit paths. n is the sub-node of the defer node that is the actual function
  4810  // call. We will also record funcdata information on where the function is stored
  4811  // (as well as the deferBits variable), and this will enable us to run the proper
  4812  // defer calls during panics.
  4813  func (s *state) openDeferRecord(n *ir.CallExpr) {
  4814  	if len(n.Args) != 0 || n.Op() != ir.OCALLFUNC || n.Fun.Type().NumResults() != 0 {
  4815  		s.Fatalf("defer call with arguments or results: %v", n)
  4816  	}
  4817  
  4818  	opendefer := &openDeferInfo{
  4819  		n: n,
  4820  	}
  4821  	fn := n.Fun
  4822  	// We must always store the function value in a stack slot for the
  4823  	// runtime panic code to use. But in the defer exit code, we will
  4824  	// call the function directly if it is a static function.
  4825  	closureVal := s.expr(fn)
  4826  	closure := s.openDeferSave(fn.Type(), closureVal)
  4827  	opendefer.closureNode = closure.Aux.(*ir.Name)
  4828  	if !(fn.Op() == ir.ONAME && fn.(*ir.Name).Class == ir.PFUNC) {
  4829  		opendefer.closure = closure
  4830  	}
  4831  	index := len(s.openDefers)
  4832  	s.openDefers = append(s.openDefers, opendefer)
  4833  
  4834  	// Update deferBits only after evaluation and storage to stack of
  4835  	// the function is successful.
  4836  	bitvalue := s.constInt8(types.Types[types.TUINT8], 1<<uint(index))
  4837  	newDeferBits := s.newValue2(ssa.OpOr8, types.Types[types.TUINT8], s.variable(deferBitsVar, types.Types[types.TUINT8]), bitvalue)
  4838  	s.vars[deferBitsVar] = newDeferBits
  4839  	s.store(types.Types[types.TUINT8], s.deferBitsAddr, newDeferBits)
  4840  }
  4841  
  4842  // openDeferSave generates SSA nodes to store a value (with type t) for an
  4843  // open-coded defer at an explicit autotmp location on the stack, so it can be
  4844  // reloaded and used for the appropriate call on exit. Type t must be a function type
  4845  // (therefore SSAable). val is the value to be stored. The function returns an SSA
  4846  // value representing a pointer to the autotmp location.
  4847  func (s *state) openDeferSave(t *types.Type, val *ssa.Value) *ssa.Value {
  4848  	if !ssa.CanSSA(t) {
  4849  		s.Fatalf("openDeferSave of non-SSA-able type %v val=%v", t, val)
  4850  	}
  4851  	if !t.HasPointers() {
  4852  		s.Fatalf("openDeferSave of pointerless type %v val=%v", t, val)
  4853  	}
  4854  	pos := val.Pos
  4855  	temp := typecheck.TempAt(pos.WithNotStmt(), s.curfn, t)
  4856  	temp.SetOpenDeferSlot(true)
  4857  	temp.SetFrameOffset(int64(len(s.openDefers))) // so cmpstackvarlt can order them
  4858  	var addrTemp *ssa.Value
  4859  	// Use OpVarLive to make sure stack slot for the closure is not removed by
  4860  	// dead-store elimination
  4861  	if s.curBlock.ID != s.f.Entry.ID {
  4862  		// Force the tmp storing this defer function to be declared in the entry
  4863  		// block, so that it will be live for the defer exit code (which will
  4864  		// actually access it only if the associated defer call has been activated).
  4865  		if t.HasPointers() {
  4866  			s.defvars[s.f.Entry.ID][memVar] = s.f.Entry.NewValue1A(src.NoXPos, ssa.OpVarDef, types.TypeMem, temp, s.defvars[s.f.Entry.ID][memVar])
  4867  		}
  4868  		s.defvars[s.f.Entry.ID][memVar] = s.f.Entry.NewValue1A(src.NoXPos, ssa.OpVarLive, types.TypeMem, temp, s.defvars[s.f.Entry.ID][memVar])
  4869  		addrTemp = s.f.Entry.NewValue2A(src.NoXPos, ssa.OpLocalAddr, types.NewPtr(temp.Type()), temp, s.sp, s.defvars[s.f.Entry.ID][memVar])
  4870  	} else {
  4871  		// Special case if we're still in the entry block. We can't use
  4872  		// the above code, since s.defvars[s.f.Entry.ID] isn't defined
  4873  		// until we end the entry block with s.endBlock().
  4874  		if t.HasPointers() {
  4875  			s.vars[memVar] = s.newValue1Apos(ssa.OpVarDef, types.TypeMem, temp, s.mem(), false)
  4876  		}
  4877  		s.vars[memVar] = s.newValue1Apos(ssa.OpVarLive, types.TypeMem, temp, s.mem(), false)
  4878  		addrTemp = s.newValue2Apos(ssa.OpLocalAddr, types.NewPtr(temp.Type()), temp, s.sp, s.mem(), false)
  4879  	}
  4880  	// Since we may use this temp during exit depending on the
  4881  	// deferBits, we must define it unconditionally on entry.
  4882  	// Therefore, we must make sure it is zeroed out in the entry
  4883  	// block if it contains pointers, else GC may wrongly follow an
  4884  	// uninitialized pointer value.
  4885  	temp.SetNeedzero(true)
  4886  	// We are storing to the stack, hence we can avoid the full checks in
  4887  	// storeType() (no write barrier) and do a simple store().
  4888  	s.store(t, addrTemp, val)
  4889  	return addrTemp
  4890  }
  4891  
  4892  // openDeferExit generates SSA for processing all the open coded defers at exit.
  4893  // The code involves loading deferBits, and checking each of the bits to see if
  4894  // the corresponding defer statement was executed. For each bit that is turned
  4895  // on, the associated defer call is made.
  4896  func (s *state) openDeferExit() {
  4897  	deferExit := s.f.NewBlock(block.BlockPlain)
  4898  	s.endBlock().AddEdgeTo(deferExit)
  4899  	s.startBlock(deferExit)
  4900  	s.lastDeferExit = deferExit
  4901  	s.lastDeferCount = len(s.openDefers)
  4902  	zeroval := s.constInt8(types.Types[types.TUINT8], 0)
  4903  	// Test for and run defers in reverse order
  4904  	for i := len(s.openDefers) - 1; i >= 0; i-- {
  4905  		r := s.openDefers[i]
  4906  		bCond := s.f.NewBlock(block.BlockPlain)
  4907  		bEnd := s.f.NewBlock(block.BlockPlain)
  4908  
  4909  		deferBits := s.variable(deferBitsVar, types.Types[types.TUINT8])
  4910  		// Generate code to check if the bit associated with the current
  4911  		// defer is set.
  4912  		bitval := s.constInt8(types.Types[types.TUINT8], 1<<uint(i))
  4913  		andval := s.newValue2(ssa.OpAnd8, types.Types[types.TUINT8], deferBits, bitval)
  4914  		eqVal := s.newValue2(ssa.OpEq8, types.Types[types.TBOOL], andval, zeroval)
  4915  		b := s.endBlock()
  4916  		b.Kind = block.BlockIf
  4917  		b.SetControl(eqVal)
  4918  		b.AddEdgeTo(bEnd)
  4919  		b.AddEdgeTo(bCond)
  4920  		bCond.AddEdgeTo(bEnd)
  4921  		s.startBlock(bCond)
  4922  
  4923  		// Clear this bit in deferBits and force store back to stack, so
  4924  		// we will not try to re-run this defer call if this defer call panics.
  4925  		nbitval := s.newValue1(ssa.OpCom8, types.Types[types.TUINT8], bitval)
  4926  		maskedval := s.newValue2(ssa.OpAnd8, types.Types[types.TUINT8], deferBits, nbitval)
  4927  		s.store(types.Types[types.TUINT8], s.deferBitsAddr, maskedval)
  4928  		// Use this value for following tests, so we keep previous
  4929  		// bits cleared.
  4930  		s.vars[deferBitsVar] = maskedval
  4931  
  4932  		// Generate code to call the function call of the defer, using the
  4933  		// closure that were stored in argtmps at the point of the defer
  4934  		// statement.
  4935  		fn := r.n.Fun
  4936  		stksize := fn.Type().ArgWidth()
  4937  		var callArgs []*ssa.Value
  4938  		var call *ssa.Value
  4939  		if r.closure != nil {
  4940  			v := s.load(r.closure.Type.Elem(), r.closure)
  4941  			s.maybeNilCheckClosure(v, callDefer)
  4942  			codeptr := s.rawLoad(types.Types[types.TUINTPTR], v)
  4943  			aux := ssa.ClosureAuxCall(s.f.ABIDefault.ABIAnalyzeTypes(nil, nil))
  4944  			call = s.newValue2A(ssa.OpClosureLECall, aux.LateExpansionResultType(), aux, codeptr, v)
  4945  		} else {
  4946  			aux := ssa.StaticAuxCall(fn.(*ir.Name).Linksym(), s.f.ABIDefault.ABIAnalyzeTypes(nil, nil))
  4947  			call = s.newValue0A(ssa.OpStaticLECall, aux.LateExpansionResultType(), aux)
  4948  		}
  4949  		callArgs = append(callArgs, s.mem())
  4950  		call.AddArgs(callArgs...)
  4951  		call.AuxInt = stksize
  4952  		s.vars[memVar] = s.newValue1I(ssa.OpSelectN, types.TypeMem, 0, call)
  4953  		// Make sure that the stack slots with pointers are kept live
  4954  		// through the call (which is a pre-emption point). Also, we will
  4955  		// use the first call of the last defer exit to compute liveness
  4956  		// for the deferreturn, so we want all stack slots to be live.
  4957  		if r.closureNode != nil {
  4958  			s.vars[memVar] = s.newValue1Apos(ssa.OpVarLive, types.TypeMem, r.closureNode, s.mem(), false)
  4959  		}
  4960  
  4961  		s.endBlock()
  4962  		s.startBlock(bEnd)
  4963  	}
  4964  }
  4965  
  4966  func (s *state) callResult(n *ir.CallExpr, k callKind) *ssa.Value {
  4967  	return s.call(n, k, false, nil)
  4968  }
  4969  
  4970  func (s *state) callAddr(n *ir.CallExpr, k callKind) *ssa.Value {
  4971  	return s.call(n, k, true, nil)
  4972  }
  4973  
  4974  // Calls the function n using the specified call type.
  4975  // Returns the address of the return value (or nil if none).
  4976  func (s *state) call(n *ir.CallExpr, k callKind, returnResultAddr bool, deferExtra ir.Expr) *ssa.Value {
  4977  	s.prevCall = nil
  4978  	var calleeLSym *obj.LSym // target function (if static)
  4979  	var closure *ssa.Value   // ptr to closure to run (if dynamic)
  4980  	var codeptr *ssa.Value   // ptr to target code (if dynamic)
  4981  	var dextra *ssa.Value    // defer extra arg
  4982  	var rcvr *ssa.Value      // receiver to set
  4983  	fn := n.Fun
  4984  	var ACArgs []*types.Type    // AuxCall args
  4985  	var ACResults []*types.Type // AuxCall results
  4986  	var callArgs []*ssa.Value   // For late-expansion, the args themselves (not stored, args to the call instead).
  4987  
  4988  	callABI := s.f.ABIDefault
  4989  
  4990  	if k != callNormal && k != callTail && (len(n.Args) != 0 || n.Op() == ir.OCALLINTER || n.Fun.Type().NumResults() != 0) {
  4991  		s.Fatalf("go/defer call with arguments: %v", n)
  4992  	}
  4993  
  4994  	isCallDeferRangeFunc := false
  4995  
  4996  	switch n.Op() {
  4997  	case ir.OCALLFUNC:
  4998  		if (k == callNormal || k == callTail) && fn.Op() == ir.ONAME && fn.(*ir.Name).Class == ir.PFUNC {
  4999  			fn := fn.(*ir.Name)
  5000  			calleeLSym = callTargetLSym(fn)
  5001  			if buildcfg.Experiment.RegabiArgs {
  5002  				// This is a static call, so it may be
  5003  				// a direct call to a non-ABIInternal
  5004  				// function. fn.Func may be nil for
  5005  				// some compiler-generated functions,
  5006  				// but those are all ABIInternal.
  5007  				if fn.Func != nil {
  5008  					callABI = abiForFunc(fn.Func, s.f.ABI0, s.f.ABI1)
  5009  				}
  5010  			} else {
  5011  				// TODO(register args) remove after register abi is working
  5012  				inRegistersImported := fn.Pragma()&ir.RegisterParams != 0
  5013  				inRegistersSamePackage := fn.Func != nil && fn.Func.Pragma&ir.RegisterParams != 0
  5014  				if inRegistersImported || inRegistersSamePackage {
  5015  					callABI = s.f.ABI1
  5016  				}
  5017  			}
  5018  			if fn := n.Fun.Sym().Name; n.Fun.Sym().Pkg == ir.Pkgs.Runtime && fn == "deferrangefunc" {
  5019  				isCallDeferRangeFunc = true
  5020  			}
  5021  			break
  5022  		}
  5023  		closure = s.expr(fn)
  5024  		if k != callDefer && k != callDeferStack {
  5025  			// Deferred nil function needs to panic when the function is invoked,
  5026  			// not the point of defer statement.
  5027  			s.maybeNilCheckClosure(closure, k)
  5028  		}
  5029  	case ir.OCALLINTER:
  5030  		if fn.Op() != ir.ODOTINTER {
  5031  			s.Fatalf("OCALLINTER: n.Left not an ODOTINTER: %v", fn.Op())
  5032  		}
  5033  		fn := fn.(*ir.SelectorExpr)
  5034  		var iclosure *ssa.Value
  5035  		iclosure, rcvr = s.getClosureAndRcvr(fn)
  5036  		if k == callNormal || k == callTail {
  5037  			codeptr = s.load(types.Types[types.TUINTPTR], iclosure)
  5038  		} else {
  5039  			closure = iclosure
  5040  		}
  5041  	}
  5042  	if deferExtra != nil {
  5043  		dextra = s.expr(deferExtra)
  5044  	}
  5045  
  5046  	params := callABI.ABIAnalyze(n.Fun.Type(), false /* Do not set (register) nNames from caller side -- can cause races. */)
  5047  	types.CalcSize(fn.Type())
  5048  	stksize := params.ArgWidth() // includes receiver, args, and results
  5049  
  5050  	res := n.Fun.Type().Results()
  5051  	if k == callNormal || k == callTail {
  5052  		for _, p := range params.OutParams() {
  5053  			ACResults = append(ACResults, p.Type)
  5054  		}
  5055  	}
  5056  
  5057  	var call *ssa.Value
  5058  	if k == callDeferStack {
  5059  		if stksize != 0 {
  5060  			s.Fatalf("deferprocStack with non-zero stack size %d: %v", stksize, n)
  5061  		}
  5062  		// Make a defer struct on the stack.
  5063  		t := deferstruct()
  5064  		n, addr := s.temp(n.Pos(), t)
  5065  		n.SetNonMergeable(true)
  5066  		s.store(closure.Type,
  5067  			s.newValue1I(ssa.OpOffPtr, closure.Type.PtrTo(), t.FieldOff(deferStructFnField), addr),
  5068  			closure)
  5069  
  5070  		// Call runtime.deferprocStack with pointer to _defer record.
  5071  		ACArgs = append(ACArgs, types.Types[types.TUINTPTR])
  5072  		aux := ssa.StaticAuxCall(ir.Syms.DeferprocStack, s.f.ABIDefault.ABIAnalyzeTypes(ACArgs, ACResults))
  5073  		callArgs = append(callArgs, addr, s.mem())
  5074  		call = s.newValue0A(ssa.OpStaticLECall, aux.LateExpansionResultType(), aux)
  5075  		call.AddArgs(callArgs...)
  5076  		call.AuxInt = int64(types.PtrSize) // deferprocStack takes a *_defer arg
  5077  	} else {
  5078  		// Store arguments to stack, including defer/go arguments and receiver for method calls.
  5079  		// These are written in SP-offset order.
  5080  		argStart := base.Ctxt.Arch.FixedFrameSize
  5081  		// Defer/go args.
  5082  		if k != callNormal && k != callTail {
  5083  			// Write closure (arg to newproc/deferproc).
  5084  			ACArgs = append(ACArgs, types.Types[types.TUINTPTR]) // not argExtra
  5085  			callArgs = append(callArgs, closure)
  5086  			stksize += int64(types.PtrSize)
  5087  			argStart += int64(types.PtrSize)
  5088  			if dextra != nil {
  5089  				// Extra token of type any for deferproc
  5090  				ACArgs = append(ACArgs, types.Types[types.TINTER])
  5091  				callArgs = append(callArgs, dextra)
  5092  				stksize += 2 * int64(types.PtrSize)
  5093  				argStart += 2 * int64(types.PtrSize)
  5094  			}
  5095  		}
  5096  
  5097  		// Set receiver (for interface calls).
  5098  		if rcvr != nil {
  5099  			callArgs = append(callArgs, rcvr)
  5100  		}
  5101  
  5102  		// Write args.
  5103  		t := n.Fun.Type()
  5104  		args := n.Args
  5105  
  5106  		for _, p := range params.InParams() { // includes receiver for interface calls
  5107  			ACArgs = append(ACArgs, p.Type)
  5108  		}
  5109  
  5110  		// Split the entry block if there are open defers, because later calls to
  5111  		// openDeferSave may cause a mismatch between the mem for an OpDereference
  5112  		// and the call site which uses it. See #49282.
  5113  		if s.curBlock.ID == s.f.Entry.ID && s.hasOpenDefers {
  5114  			b := s.endBlock()
  5115  			b.Kind = block.BlockPlain
  5116  			curb := s.f.NewBlock(block.BlockPlain)
  5117  			b.AddEdgeTo(curb)
  5118  			s.startBlock(curb)
  5119  		}
  5120  
  5121  		for i, n := range args {
  5122  			callArgs = append(callArgs, s.putArg(n, t.Param(i).Type))
  5123  		}
  5124  
  5125  		callArgs = append(callArgs, s.mem())
  5126  
  5127  		// call target
  5128  		switch {
  5129  		case k == callDefer:
  5130  			sym := ir.Syms.Deferproc
  5131  			if dextra != nil {
  5132  				sym = ir.Syms.Deferprocat
  5133  			}
  5134  			aux := ssa.StaticAuxCall(sym, s.f.ABIDefault.ABIAnalyzeTypes(ACArgs, ACResults)) // TODO paramResultInfo for Deferproc(at)
  5135  			call = s.newValue0A(ssa.OpStaticLECall, aux.LateExpansionResultType(), aux)
  5136  		case k == callGo:
  5137  			aux := ssa.StaticAuxCall(ir.Syms.Newproc, s.f.ABIDefault.ABIAnalyzeTypes(ACArgs, ACResults))
  5138  			call = s.newValue0A(ssa.OpStaticLECall, aux.LateExpansionResultType(), aux) // TODO paramResultInfo for Newproc
  5139  		case closure != nil:
  5140  			// rawLoad because loading the code pointer from a
  5141  			// closure is always safe, but IsSanitizerSafeAddr
  5142  			// can't always figure that out currently, and it's
  5143  			// critical that we not clobber any arguments already
  5144  			// stored onto the stack.
  5145  			codeptr = s.rawLoad(types.Types[types.TUINTPTR], closure)
  5146  			aux := ssa.ClosureAuxCall(callABI.ABIAnalyzeTypes(ACArgs, ACResults))
  5147  			call = s.newValue2A(ssa.OpClosureLECall, aux.LateExpansionResultType(), aux, codeptr, closure)
  5148  		case codeptr != nil:
  5149  			// Note that the "receiver" parameter is nil because the actual receiver is the first input parameter.
  5150  			aux := ssa.InterfaceAuxCall(params)
  5151  			call = s.newValue1A(ssa.OpInterLECall, aux.LateExpansionResultType(), aux, codeptr)
  5152  			if k == callTail {
  5153  				call.Op = ssa.OpTailLECallInter
  5154  				stksize = 0 // Tail call does not use stack. We reuse caller's frame.
  5155  			}
  5156  		case calleeLSym != nil:
  5157  			aux := ssa.StaticAuxCall(calleeLSym, params)
  5158  			call = s.newValue0A(ssa.OpStaticLECall, aux.LateExpansionResultType(), aux)
  5159  			if k == callTail {
  5160  				call.Op = ssa.OpTailLECall
  5161  				stksize = 0 // Tail call does not use stack. We reuse caller's frame.
  5162  			}
  5163  		default:
  5164  			s.Fatalf("bad call type %v %v", n.Op(), n)
  5165  		}
  5166  		call.AddArgs(callArgs...)
  5167  		call.AuxInt = stksize // Call operations carry the argsize of the callee along with them
  5168  	}
  5169  	s.prevCall = call
  5170  	s.vars[memVar] = s.newValue1I(ssa.OpSelectN, types.TypeMem, int64(len(ACResults)), call)
  5171  	// Insert VarLive opcodes.
  5172  	for _, v := range n.KeepAlive {
  5173  		if !v.Addrtaken() {
  5174  			s.Fatalf("KeepAlive variable %v must have Addrtaken set", v)
  5175  		}
  5176  		switch v.Class {
  5177  		case ir.PAUTO, ir.PPARAM, ir.PPARAMOUT:
  5178  		default:
  5179  			s.Fatalf("KeepAlive variable %v must be Auto or Arg", v)
  5180  		}
  5181  		s.vars[memVar] = s.newValue1A(ssa.OpVarLive, types.TypeMem, v, s.mem())
  5182  	}
  5183  
  5184  	// Build result value (before we might end the defer block, below).
  5185  	var result *ssa.Value
  5186  	if len(res) == 0 || k != callNormal {
  5187  		result = nil
  5188  	} else {
  5189  		fp := res[0]
  5190  		if returnResultAddr {
  5191  			result = s.resultAddrOfCall(call, 0, fp.Type)
  5192  		} else {
  5193  			result = s.newValue1I(ssa.OpSelectN, fp.Type, 0, call)
  5194  		}
  5195  		if n.Reshape {
  5196  			result = s.newValue1(ssa.OpCopy, n.Type(), result)
  5197  		}
  5198  	}
  5199  
  5200  	// Finish block for defers
  5201  	if k == callDefer || k == callDeferStack || isCallDeferRangeFunc {
  5202  		b := s.endBlock()
  5203  		b.Kind = block.BlockDefer
  5204  		b.SetControl(call)
  5205  		bNext := s.f.NewBlock(block.BlockPlain)
  5206  		b.AddEdgeTo(bNext)
  5207  		r := s.f.DeferReturn // Share a single deferreturn among all defers
  5208  		if r == nil {
  5209  			r = s.f.NewBlock(block.BlockPlain)
  5210  			s.startBlock(r)
  5211  			s.exit()
  5212  			s.f.DeferReturn = r
  5213  		}
  5214  		b.AddEdgeTo(r) // Add recover edge to exit code.  This is a fake edge to keep the block live.
  5215  		b.Likely = ssa.BranchLikely
  5216  		s.startBlock(bNext)
  5217  	}
  5218  
  5219  	return result
  5220  }
  5221  
  5222  // maybeNilCheckClosure checks if a nil check of a closure is needed in some
  5223  // architecture-dependent situations and, if so, emits the nil check.
  5224  func (s *state) maybeNilCheckClosure(closure *ssa.Value, k callKind) {
  5225  	if Arch.LinkArch.Family == sys.Wasm || buildcfg.GOOS == "aix" && k != callGo {
  5226  		// On AIX, the closure needs to be verified as fn can be nil, except if it's a call go. This needs to be handled by the runtime to have the "go of nil func value" error.
  5227  		// TODO(neelance): On other architectures this should be eliminated by the optimization steps
  5228  		s.nilCheck(closure)
  5229  	}
  5230  }
  5231  
  5232  // getClosureAndRcvr returns values for the appropriate closure and receiver of an
  5233  // interface call
  5234  func (s *state) getClosureAndRcvr(fn *ir.SelectorExpr) (*ssa.Value, *ssa.Value) {
  5235  	i := s.expr(fn.X)
  5236  	itab := s.newValue1(ssa.OpITab, types.Types[types.TUINTPTR], i)
  5237  	s.nilCheck(itab)
  5238  	itabidx := fn.Offset() + rttype.ITab.OffsetOf("Fun")
  5239  	closure := s.newValue1I(ssa.OpOffPtr, s.f.Config.Types.UintptrPtr, itabidx, itab)
  5240  	rcvr := s.newValue1(ssa.OpIData, s.f.Config.Types.BytePtr, i)
  5241  	return closure, rcvr
  5242  }
  5243  
  5244  // etypesign returns the signed-ness of e, for integer/pointer etypes.
  5245  // -1 means signed, +1 means unsigned, 0 means non-integer/non-pointer.
  5246  func etypesign(e types.Kind) int8 {
  5247  	switch e {
  5248  	case types.TINT8, types.TINT16, types.TINT32, types.TINT64, types.TINT:
  5249  		return -1
  5250  	case types.TUINT8, types.TUINT16, types.TUINT32, types.TUINT64, types.TUINT, types.TUINTPTR, types.TUNSAFEPTR:
  5251  		return +1
  5252  	}
  5253  	return 0
  5254  }
  5255  
  5256  // addr converts the address of the expression n to SSA, adds it to s and returns the SSA result.
  5257  // The value that the returned Value represents is guaranteed to be non-nil.
  5258  func (s *state) addr(n ir.Node) *ssa.Value {
  5259  	if n.Op() != ir.ONAME {
  5260  		s.pushLine(n.Pos())
  5261  		defer s.popLine()
  5262  	}
  5263  
  5264  	if s.canSSA(n) {
  5265  		// This happens in weird, always-panics cases, like:
  5266  		//     var x [0][2]int
  5267  		//     x[i][j] = 5
  5268  		// The outer assignment, ...[j] = 5, is a fine
  5269  		// assignment to do, but requires computing the address
  5270  		// &x[i], which will always panic when evaluated.
  5271  		// We just return something reasonable in this case.
  5272  		// It will be dynamically unreachable. See issue 77635.
  5273  		s.boundsCheckArrayIndex(n)
  5274  		return s.newValue1A(ssa.OpAddr, n.Type().PtrTo(), ir.Syms.Zerobase, s.sb)
  5275  	}
  5276  
  5277  	t := types.NewPtr(n.Type())
  5278  	linksymOffset := func(lsym *obj.LSym, offset int64) *ssa.Value {
  5279  		v := s.entryNewValue1A(ssa.OpAddr, t, lsym, s.sb)
  5280  		// TODO: Make OpAddr use AuxInt as well as Aux.
  5281  		if offset != 0 {
  5282  			v = s.entryNewValue1I(ssa.OpOffPtr, v.Type, offset, v)
  5283  		}
  5284  		return v
  5285  	}
  5286  	switch n.Op() {
  5287  	case ir.OLINKSYMOFFSET:
  5288  		no := n.(*ir.LinksymOffsetExpr)
  5289  		return linksymOffset(no.Linksym, no.Offset_)
  5290  	case ir.ONAME:
  5291  		n := n.(*ir.Name)
  5292  		if n.Heapaddr != nil {
  5293  			return s.expr(n.Heapaddr)
  5294  		}
  5295  		switch n.Class {
  5296  		case ir.PEXTERN:
  5297  			// global variable
  5298  			return linksymOffset(n.Linksym(), 0)
  5299  		case ir.PPARAM:
  5300  			// parameter slot
  5301  			v := s.decladdrs[n]
  5302  			if v != nil {
  5303  				return v
  5304  			}
  5305  			s.Fatalf("addr of undeclared ONAME %v. declared: %v", n, s.decladdrs)
  5306  			return nil
  5307  		case ir.PAUTO:
  5308  			return s.newValue2Apos(ssa.OpLocalAddr, t, n, s.sp, s.mem(), !ir.IsAutoTmp(n))
  5309  
  5310  		case ir.PPARAMOUT: // Same as PAUTO -- cannot generate LEA early.
  5311  			// ensure that we reuse symbols for out parameters so
  5312  			// that cse works on their addresses
  5313  			return s.newValue2Apos(ssa.OpLocalAddr, t, n, s.sp, s.mem(), true)
  5314  		default:
  5315  			s.Fatalf("variable address class %v not implemented", n.Class)
  5316  			return nil
  5317  		}
  5318  	case ir.ORESULT:
  5319  		// load return from callee
  5320  		n := n.(*ir.ResultExpr)
  5321  		return s.resultAddrOfCall(s.prevCall, n.Index, n.Type())
  5322  	case ir.OINDEX:
  5323  		n := n.(*ir.IndexExpr)
  5324  		if n.X.Type().IsSlice() {
  5325  			a := s.expr(n.X)
  5326  			i := s.expr(n.Index)
  5327  			len := s.newValue1(ssa.OpSliceLen, types.Types[types.TINT], a)
  5328  			i = s.boundsCheck(i, len, ssa.BoundsIndex, n.Bounded())
  5329  			p := s.newValue1(ssa.OpSlicePtr, t, a)
  5330  			return s.newValue2(ssa.OpPtrIndex, t, p, i)
  5331  		} else { // array
  5332  			a := s.addr(n.X)
  5333  			i := s.expr(n.Index)
  5334  			len := s.constInt(types.Types[types.TINT], n.X.Type().NumElem())
  5335  			i = s.boundsCheck(i, len, ssa.BoundsIndex, n.Bounded())
  5336  			return s.newValue2(ssa.OpPtrIndex, types.NewPtr(n.X.Type().Elem()), a, i)
  5337  		}
  5338  	case ir.ODEREF:
  5339  		n := n.(*ir.StarExpr)
  5340  		return s.exprPtr(n.X, n.Bounded(), n.Pos())
  5341  	case ir.ODOT:
  5342  		n := n.(*ir.SelectorExpr)
  5343  		p := s.addr(n.X)
  5344  		return s.newValue1I(ssa.OpOffPtr, t, n.Offset(), p)
  5345  	case ir.ODOTPTR:
  5346  		n := n.(*ir.SelectorExpr)
  5347  		p := s.exprPtr(n.X, n.Bounded(), n.Pos())
  5348  		return s.newValue1I(ssa.OpOffPtr, t, n.Offset(), p)
  5349  	case ir.OCONVNOP:
  5350  		n := n.(*ir.ConvExpr)
  5351  		if n.Type() == n.X.Type() {
  5352  			return s.addr(n.X)
  5353  		}
  5354  		addr := s.addr(n.X)
  5355  		return s.newValue1(ssa.OpCopy, t, addr) // ensure that addr has the right type
  5356  	case ir.OCALLFUNC, ir.OCALLINTER:
  5357  		n := n.(*ir.CallExpr)
  5358  		return s.callAddr(n, callNormal)
  5359  	case ir.ODOTTYPE, ir.ODYNAMICDOTTYPE:
  5360  		var v *ssa.Value
  5361  		if n.Op() == ir.ODOTTYPE {
  5362  			v, _ = s.dottype(n.(*ir.TypeAssertExpr), false)
  5363  		} else {
  5364  			v, _ = s.dynamicDottype(n.(*ir.DynamicTypeAssertExpr), false)
  5365  		}
  5366  		if v.Op != ssa.OpLoad {
  5367  			s.Fatalf("dottype of non-load")
  5368  		}
  5369  		if v.Args[1] != s.mem() {
  5370  			s.Fatalf("memory no longer live from dottype load")
  5371  		}
  5372  		return v.Args[0]
  5373  	default:
  5374  		s.Fatalf("unhandled addr %v", n.Op())
  5375  		return nil
  5376  	}
  5377  }
  5378  
  5379  // canSSA reports whether n is SSA-able.
  5380  // n must be an ONAME (or an ODOT sequence with an ONAME base).
  5381  func (s *state) canSSA(n ir.Node) bool {
  5382  	if base.Flag.N != 0 {
  5383  		return false
  5384  	}
  5385  	for {
  5386  		nn := n
  5387  		if nn.Op() == ir.ODOT {
  5388  			nn := nn.(*ir.SelectorExpr)
  5389  			n = nn.X
  5390  			continue
  5391  		}
  5392  		if nn.Op() == ir.OINDEX {
  5393  			nn := nn.(*ir.IndexExpr)
  5394  			if nn.X.Type().IsArray() {
  5395  				n = nn.X
  5396  				continue
  5397  			}
  5398  		}
  5399  		break
  5400  	}
  5401  	if n.Op() != ir.ONAME {
  5402  		return false
  5403  	}
  5404  	return s.canSSAName(n.(*ir.Name)) && ssa.CanSSA(n.Type())
  5405  }
  5406  
  5407  func (s *state) canSSAName(name *ir.Name) bool {
  5408  	if name.Addrtaken() || !name.OnStack() {
  5409  		return false
  5410  	}
  5411  	switch name.Class {
  5412  	case ir.PPARAMOUT:
  5413  		if s.hasdefer {
  5414  			// TODO: handle this case? Named return values must be
  5415  			// in memory so that the deferred function can see them.
  5416  			// Maybe do: if !strings.HasPrefix(n.String(), "~") { return false }
  5417  			// Or maybe not, see issue 18860.  Even unnamed return values
  5418  			// must be written back so if a defer recovers, the caller can see them.
  5419  			return false
  5420  		}
  5421  		if s.cgoUnsafeArgs {
  5422  			// Cgo effectively takes the address of all result args,
  5423  			// but the compiler can't see that.
  5424  			return false
  5425  		}
  5426  	}
  5427  	return true
  5428  	// TODO: try to make more variables SSAable?
  5429  }
  5430  
  5431  // exprPtr evaluates n to a pointer and nil-checks it.
  5432  func (s *state) exprPtr(n ir.Node, bounded bool, lineno src.XPos) *ssa.Value {
  5433  	p := s.expr(n)
  5434  	if bounded || n.NonNil() {
  5435  		if s.f.Frontend().Debug_checknil() && lineno.Line() > 1 {
  5436  			s.f.Warnl(lineno, "removed nil check")
  5437  		}
  5438  		return p
  5439  	}
  5440  	p = s.nilCheck(p)
  5441  	return p
  5442  }
  5443  
  5444  // nilCheck generates nil pointer checking code.
  5445  // Used only for automatically inserted nil checks,
  5446  // not for user code like 'x != nil'.
  5447  // Returns a "definitely not nil" copy of x to ensure proper ordering
  5448  // of the uses of the post-nilcheck pointer.
  5449  func (s *state) nilCheck(ptr *ssa.Value) *ssa.Value {
  5450  	if base.Debug.DisableNil != 0 || s.curfn.NilCheckDisabled() {
  5451  		return ptr
  5452  	}
  5453  	return s.newValue2(ssa.OpNilCheck, ptr.Type, ptr, s.mem())
  5454  }
  5455  
  5456  // boundsCheckArrayIndex generates bounds checking code for array indexing operations.
  5457  func (s *state) boundsCheckArrayIndex(n ir.Node) {
  5458  	if n.Op() != ir.OINDEX {
  5459  		return
  5460  	}
  5461  	nn := n.(*ir.IndexExpr)
  5462  	typ := nn.X.Type()
  5463  	if typ.IsArray() {
  5464  		_ = s.expr(nn.X) // for side effects
  5465  		idx := s.expr(nn.Index)
  5466  		len := s.constInt(types.Types[types.TINT], typ.NumElem())
  5467  		s.boundsCheck(idx, len, ssa.BoundsIndex, nn.Bounded())
  5468  	}
  5469  }
  5470  
  5471  // boundsCheck generates bounds checking code. Checks if 0 <= idx <[=] len, branches to exit if not.
  5472  // Starts a new block on return.
  5473  // On input, len must be converted to full int width and be nonnegative.
  5474  // Returns idx converted to full int width.
  5475  // If bounded is true then caller guarantees the index is not out of bounds
  5476  // (but boundsCheck will still extend the index to full int width).
  5477  func (s *state) boundsCheck(idx, len *ssa.Value, kind ssa.BoundsKind, bounded bool) *ssa.Value {
  5478  	idx = s.extendIndex(idx, len, kind, bounded)
  5479  
  5480  	if bounded || base.Flag.B != 0 {
  5481  		// If bounded or bounds checking is flag-disabled, then no check necessary,
  5482  		// just return the extended index.
  5483  		//
  5484  		// Here, bounded == true if the compiler generated the index itself,
  5485  		// such as in the expansion of a slice initializer. These indexes are
  5486  		// compiler-generated, not Go program variables, so they cannot be
  5487  		// attacker-controlled, so we can omit Spectre masking as well.
  5488  		//
  5489  		// Note that we do not want to omit Spectre masking in code like:
  5490  		//
  5491  		//	if 0 <= i && i < len(x) {
  5492  		//		use(x[i])
  5493  		//	}
  5494  		//
  5495  		// Lucky for us, bounded==false for that code.
  5496  		// In that case (handled below), we emit a bound check (and Spectre mask)
  5497  		// and then the prove pass will remove the bounds check.
  5498  		// In theory the prove pass could potentially remove certain
  5499  		// Spectre masks, but it's very delicate and probably better
  5500  		// to be conservative and leave them all in.
  5501  		return idx
  5502  	}
  5503  
  5504  	bNext := s.f.NewBlock(block.BlockPlain)
  5505  	bPanic := s.f.NewBlock(block.BlockExit)
  5506  
  5507  	if !idx.Type.IsSigned() {
  5508  		switch kind {
  5509  		case ssa.BoundsIndex:
  5510  			kind = ssa.BoundsIndexU
  5511  		case ssa.BoundsSliceAlen:
  5512  			kind = ssa.BoundsSliceAlenU
  5513  		case ssa.BoundsSliceAcap:
  5514  			kind = ssa.BoundsSliceAcapU
  5515  		case ssa.BoundsSliceB:
  5516  			kind = ssa.BoundsSliceBU
  5517  		case ssa.BoundsSlice3Alen:
  5518  			kind = ssa.BoundsSlice3AlenU
  5519  		case ssa.BoundsSlice3Acap:
  5520  			kind = ssa.BoundsSlice3AcapU
  5521  		case ssa.BoundsSlice3B:
  5522  			kind = ssa.BoundsSlice3BU
  5523  		case ssa.BoundsSlice3C:
  5524  			kind = ssa.BoundsSlice3CU
  5525  		}
  5526  	}
  5527  
  5528  	var cmp *ssa.Value
  5529  	if kind == ssa.BoundsIndex || kind == ssa.BoundsIndexU {
  5530  		cmp = s.newValue2(ssa.OpIsInBounds, types.Types[types.TBOOL], idx, len)
  5531  	} else {
  5532  		cmp = s.newValue2(ssa.OpIsSliceInBounds, types.Types[types.TBOOL], idx, len)
  5533  	}
  5534  	b := s.endBlock()
  5535  	b.Kind = block.BlockIf
  5536  	b.SetControl(cmp)
  5537  	b.Likely = ssa.BranchLikely
  5538  	b.AddEdgeTo(bNext)
  5539  	b.AddEdgeTo(bPanic)
  5540  
  5541  	s.startBlock(bPanic)
  5542  	if Arch.LinkArch.Family == sys.Wasm {
  5543  		// TODO(khr): figure out how to do "register" based calling convention for bounds checks.
  5544  		// Should be similar to gcWriteBarrier, but I can't make it work.
  5545  		s.rtcall(BoundsCheckFunc[kind], false, nil, idx, len)
  5546  	} else {
  5547  		mem := s.newValue3I(ssa.OpPanicBounds, types.TypeMem, int64(kind), idx, len, s.mem())
  5548  		s.endBlock().SetControl(mem)
  5549  	}
  5550  	s.startBlock(bNext)
  5551  
  5552  	// In Spectre index mode, apply an appropriate mask to avoid speculative out-of-bounds accesses.
  5553  	if base.Flag.Cfg.SpectreIndex {
  5554  		op := ssa.OpSpectreIndex
  5555  		if kind != ssa.BoundsIndex && kind != ssa.BoundsIndexU {
  5556  			op = ssa.OpSpectreSliceIndex
  5557  		}
  5558  		idx = s.newValue2(op, types.Types[types.TINT], idx, len)
  5559  	}
  5560  
  5561  	return idx
  5562  }
  5563  
  5564  // If cmp (a bool) is false, panic using the given function.
  5565  func (s *state) check(cmp *ssa.Value, fn *obj.LSym) {
  5566  	b := s.endBlock()
  5567  	b.Kind = block.BlockIf
  5568  	b.SetControl(cmp)
  5569  	b.Likely = ssa.BranchLikely
  5570  	bNext := s.f.NewBlock(block.BlockPlain)
  5571  	line := s.peekPos()
  5572  	pos := base.Ctxt.PosTable.Pos(line)
  5573  	fl := funcLine{f: fn, base: pos.Base(), line: pos.Line()}
  5574  	bPanic := s.panics[fl]
  5575  	if bPanic == nil {
  5576  		bPanic = s.f.NewBlock(block.BlockPlain)
  5577  		s.panics[fl] = bPanic
  5578  		s.startBlock(bPanic)
  5579  		// The panic call takes/returns memory to ensure that the right
  5580  		// memory state is observed if the panic happens.
  5581  		s.rtcall(fn, false, nil)
  5582  	}
  5583  	b.AddEdgeTo(bNext)
  5584  	b.AddEdgeTo(bPanic)
  5585  	s.startBlock(bNext)
  5586  }
  5587  
  5588  func (s *state) intDivide(n ir.Node, a, b *ssa.Value) *ssa.Value {
  5589  	needcheck := true
  5590  	switch b.Op {
  5591  	case ssa.OpConst8, ssa.OpConst16, ssa.OpConst32, ssa.OpConst64:
  5592  		if b.AuxInt != 0 {
  5593  			needcheck = false
  5594  		}
  5595  	}
  5596  	if needcheck {
  5597  		// do a size-appropriate check for zero
  5598  		cmp := s.newValue2(s.ssaOp(ir.ONE, n.Type()), types.Types[types.TBOOL], b, s.zeroVal(n.Type()))
  5599  		s.check(cmp, ir.Syms.Panicdivide)
  5600  	}
  5601  	return s.newValue2(s.ssaOp(n.Op(), n.Type()), a.Type, a, b)
  5602  }
  5603  
  5604  // rtcall issues a call to the given runtime function fn with the listed args.
  5605  // Returns a slice of results of the given result types.
  5606  // The call is added to the end of the current block.
  5607  // If returns is false, the block is marked as an exit block.
  5608  func (s *state) rtcall(fn *obj.LSym, returns bool, results []*types.Type, args ...*ssa.Value) []*ssa.Value {
  5609  	s.prevCall = nil
  5610  	// Write args to the stack
  5611  	off := base.Ctxt.Arch.FixedFrameSize
  5612  	var callArgs []*ssa.Value
  5613  	var callArgTypes []*types.Type
  5614  
  5615  	for _, arg := range args {
  5616  		t := arg.Type
  5617  		off = types.RoundUp(off, t.Alignment())
  5618  		size := t.Size()
  5619  		callArgs = append(callArgs, arg)
  5620  		callArgTypes = append(callArgTypes, t)
  5621  		off += size
  5622  	}
  5623  	off = types.RoundUp(off, int64(types.RegSize))
  5624  
  5625  	// Issue call
  5626  	var call *ssa.Value
  5627  	aux := ssa.StaticAuxCall(fn, s.f.ABIDefault.ABIAnalyzeTypes(callArgTypes, results))
  5628  	callArgs = append(callArgs, s.mem())
  5629  	call = s.newValue0A(ssa.OpStaticLECall, aux.LateExpansionResultType(), aux)
  5630  	call.AddArgs(callArgs...)
  5631  	s.vars[memVar] = s.newValue1I(ssa.OpSelectN, types.TypeMem, int64(len(results)), call)
  5632  
  5633  	if !returns {
  5634  		// Finish block
  5635  		b := s.endBlock()
  5636  		b.Kind = block.BlockExit
  5637  		b.SetControl(call)
  5638  		call.AuxInt = off - base.Ctxt.Arch.FixedFrameSize
  5639  		if len(results) > 0 {
  5640  			s.Fatalf("panic call can't have results")
  5641  		}
  5642  		return nil
  5643  	}
  5644  
  5645  	// Load results
  5646  	res := make([]*ssa.Value, len(results))
  5647  	for i, t := range results {
  5648  		off = types.RoundUp(off, t.Alignment())
  5649  		res[i] = s.resultOfCall(call, int64(i), t)
  5650  		off += t.Size()
  5651  	}
  5652  	off = types.RoundUp(off, int64(types.PtrSize))
  5653  
  5654  	// Remember how much callee stack space we needed.
  5655  	call.AuxInt = off
  5656  
  5657  	return res
  5658  }
  5659  
  5660  // do *left = right for type t.
  5661  func (s *state) storeType(t *types.Type, left, right *ssa.Value, skip skipMask, leftIsStmt bool) {
  5662  	s.instrument(t, left, instrumentWrite)
  5663  
  5664  	if skip == 0 && (!t.HasPointers() || ssa.IsStackAddr(left)) {
  5665  		// Known to not have write barrier. Store the whole type.
  5666  		s.vars[memVar] = s.newValue3Apos(ssa.OpStore, types.TypeMem, t, left, right, s.mem(), leftIsStmt)
  5667  		return
  5668  	}
  5669  
  5670  	// store scalar fields first, so write barrier stores for
  5671  	// pointer fields can be grouped together, and scalar values
  5672  	// don't need to be live across the write barrier call.
  5673  	// TODO: if the writebarrier pass knows how to reorder stores,
  5674  	// we can do a single store here as long as skip==0.
  5675  	s.storeTypeScalars(t, left, right, skip)
  5676  	if skip&skipPtr == 0 && t.HasPointers() {
  5677  		s.storeTypePtrs(t, left, right)
  5678  	}
  5679  }
  5680  
  5681  // do *left = right for all scalar (non-pointer) parts of t.
  5682  func (s *state) storeTypeScalars(t *types.Type, left, right *ssa.Value, skip skipMask) {
  5683  	switch {
  5684  	case t.IsBoolean() || t.IsInteger() || t.IsFloat() || t.IsComplex() || t.IsSIMD():
  5685  		s.store(t, left, right)
  5686  	case t.IsPtrShaped():
  5687  		if t.IsPtr() && t.Elem().NotInHeap() {
  5688  			s.store(t, left, right) // see issue 42032
  5689  		}
  5690  		// otherwise, no scalar fields.
  5691  	case t.IsString():
  5692  		if skip&skipLen != 0 {
  5693  			return
  5694  		}
  5695  		len := s.newValue1(ssa.OpStringLen, types.Types[types.TINT], right)
  5696  		lenAddr := s.newValue1I(ssa.OpOffPtr, s.f.Config.Types.IntPtr, s.config.PtrSize, left)
  5697  		s.store(types.Types[types.TINT], lenAddr, len)
  5698  	case t.IsSlice():
  5699  		if skip&skipLen == 0 {
  5700  			len := s.newValue1(ssa.OpSliceLen, types.Types[types.TINT], right)
  5701  			lenAddr := s.newValue1I(ssa.OpOffPtr, s.f.Config.Types.IntPtr, s.config.PtrSize, left)
  5702  			s.store(types.Types[types.TINT], lenAddr, len)
  5703  		}
  5704  		if skip&skipCap == 0 {
  5705  			cap := s.newValue1(ssa.OpSliceCap, types.Types[types.TINT], right)
  5706  			capAddr := s.newValue1I(ssa.OpOffPtr, s.f.Config.Types.IntPtr, 2*s.config.PtrSize, left)
  5707  			s.store(types.Types[types.TINT], capAddr, cap)
  5708  		}
  5709  	case t.IsInterface():
  5710  		// itab field doesn't need a write barrier (even though it is a pointer).
  5711  		itab := s.newValue1(ssa.OpITab, s.f.Config.Types.BytePtr, right)
  5712  		s.store(types.Types[types.TUINTPTR], left, itab)
  5713  	case isStructNotSIMD(t):
  5714  		n := t.NumFields()
  5715  		for i := 0; i < n; i++ {
  5716  			ft := t.FieldType(i)
  5717  			addr := s.newValue1I(ssa.OpOffPtr, ft.PtrTo(), t.FieldOff(i), left)
  5718  			val := s.newValue1I(ssa.OpStructSelect, ft, int64(i), right)
  5719  			s.storeTypeScalars(ft, addr, val, 0)
  5720  		}
  5721  	case t.IsArray() && t.Size() == 0:
  5722  		// nothing
  5723  	case t.IsArray() && t.NumElem() == 1:
  5724  		s.storeTypeScalars(t.Elem(), left, s.newValue1I(ssa.OpArraySelect, t.Elem(), 0, right), 0)
  5725  	default:
  5726  		s.Fatalf("bad write barrier type %v", t)
  5727  	}
  5728  }
  5729  
  5730  // do *left = right for all pointer parts of t.
  5731  func (s *state) storeTypePtrs(t *types.Type, left, right *ssa.Value) {
  5732  	switch {
  5733  	case t.IsPtrShaped():
  5734  		if t.IsPtr() && t.Elem().NotInHeap() {
  5735  			break // see issue 42032
  5736  		}
  5737  		s.store(t, left, right)
  5738  	case t.IsString():
  5739  		ptr := s.newValue1(ssa.OpStringPtr, s.f.Config.Types.BytePtr, right)
  5740  		s.store(s.f.Config.Types.BytePtr, left, ptr)
  5741  	case t.IsSlice():
  5742  		elType := types.NewPtr(t.Elem())
  5743  		ptr := s.newValue1(ssa.OpSlicePtr, elType, right)
  5744  		s.store(elType, left, ptr)
  5745  	case t.IsInterface():
  5746  		// itab field is treated as a scalar.
  5747  		idata := s.newValue1(ssa.OpIData, s.f.Config.Types.BytePtr, right)
  5748  		idataAddr := s.newValue1I(ssa.OpOffPtr, s.f.Config.Types.BytePtrPtr, s.config.PtrSize, left)
  5749  		s.store(s.f.Config.Types.BytePtr, idataAddr, idata)
  5750  	case isStructNotSIMD(t):
  5751  		n := t.NumFields()
  5752  		for i := 0; i < n; i++ {
  5753  			ft := t.FieldType(i)
  5754  			if !ft.HasPointers() {
  5755  				continue
  5756  			}
  5757  			addr := s.newValue1I(ssa.OpOffPtr, ft.PtrTo(), t.FieldOff(i), left)
  5758  			val := s.newValue1I(ssa.OpStructSelect, ft, int64(i), right)
  5759  			s.storeTypePtrs(ft, addr, val)
  5760  		}
  5761  	case t.IsArray() && t.Size() == 0:
  5762  		// nothing
  5763  	case t.IsArray() && t.NumElem() == 1:
  5764  		s.storeTypePtrs(t.Elem(), left, s.newValue1I(ssa.OpArraySelect, t.Elem(), 0, right))
  5765  	default:
  5766  		s.Fatalf("bad write barrier type %v", t)
  5767  	}
  5768  }
  5769  
  5770  // putArg evaluates n for the purpose of passing it as an argument to a function and returns the value for the call.
  5771  func (s *state) putArg(n ir.Node, t *types.Type) *ssa.Value {
  5772  	var a *ssa.Value
  5773  	if !ssa.CanSSA(t) {
  5774  		a = s.newValue2(ssa.OpDereference, t, s.addr(n), s.mem())
  5775  	} else {
  5776  		a = s.expr(n)
  5777  	}
  5778  	return a
  5779  }
  5780  
  5781  // slice computes the slice v[i:j:k] and returns ptr, len, and cap of result.
  5782  // i,j,k may be nil, in which case they are set to their default value.
  5783  // v may be a slice, string or pointer to an array.
  5784  func (s *state) slice(v, i, j, k *ssa.Value, bounded bool) (p, l, c *ssa.Value) {
  5785  	t := v.Type
  5786  	var ptr, len, cap *ssa.Value
  5787  	switch {
  5788  	case t.IsSlice():
  5789  		ptr = s.newValue1(ssa.OpSlicePtr, types.NewPtr(t.Elem()), v)
  5790  		len = s.newValue1(ssa.OpSliceLen, types.Types[types.TINT], v)
  5791  		cap = s.newValue1(ssa.OpSliceCap, types.Types[types.TINT], v)
  5792  	case t.IsString():
  5793  		ptr = s.newValue1(ssa.OpStringPtr, types.NewPtr(types.Types[types.TUINT8]), v)
  5794  		len = s.newValue1(ssa.OpStringLen, types.Types[types.TINT], v)
  5795  		cap = len
  5796  	case t.IsPtr():
  5797  		if !t.Elem().IsArray() {
  5798  			s.Fatalf("bad ptr to array in slice %v\n", t)
  5799  		}
  5800  		nv := s.nilCheck(v)
  5801  		ptr = s.newValue1(ssa.OpCopy, types.NewPtr(t.Elem().Elem()), nv)
  5802  		len = s.constInt(types.Types[types.TINT], t.Elem().NumElem())
  5803  		cap = len
  5804  	default:
  5805  		s.Fatalf("bad type in slice %v\n", t)
  5806  	}
  5807  
  5808  	// Set default values
  5809  	if i == nil {
  5810  		i = s.constInt(types.Types[types.TINT], 0)
  5811  	}
  5812  	if j == nil {
  5813  		j = len
  5814  	}
  5815  	three := true
  5816  	if k == nil {
  5817  		three = false
  5818  		k = cap
  5819  	}
  5820  
  5821  	// Panic if slice indices are not in bounds.
  5822  	// Make sure we check these in reverse order so that we're always
  5823  	// comparing against a value known to be nonnegative. See issue 28797.
  5824  	if three {
  5825  		if k != cap {
  5826  			kind := ssa.BoundsSlice3Alen
  5827  			if t.IsSlice() {
  5828  				kind = ssa.BoundsSlice3Acap
  5829  			}
  5830  			k = s.boundsCheck(k, cap, kind, bounded)
  5831  		}
  5832  		if j != k {
  5833  			j = s.boundsCheck(j, k, ssa.BoundsSlice3B, bounded)
  5834  		}
  5835  		i = s.boundsCheck(i, j, ssa.BoundsSlice3C, bounded)
  5836  	} else {
  5837  		if j != k {
  5838  			kind := ssa.BoundsSliceAlen
  5839  			if t.IsSlice() {
  5840  				kind = ssa.BoundsSliceAcap
  5841  			}
  5842  			j = s.boundsCheck(j, k, kind, bounded)
  5843  		}
  5844  		i = s.boundsCheck(i, j, ssa.BoundsSliceB, bounded)
  5845  	}
  5846  
  5847  	// Word-sized integer operations.
  5848  	subOp := s.ssaOp(ir.OSUB, types.Types[types.TINT])
  5849  	mulOp := s.ssaOp(ir.OMUL, types.Types[types.TINT])
  5850  	andOp := s.ssaOp(ir.OAND, types.Types[types.TINT])
  5851  
  5852  	// Calculate the length (rlen) and capacity (rcap) of the new slice.
  5853  	// For strings the capacity of the result is unimportant. However,
  5854  	// we use rcap to test if we've generated a zero-length slice.
  5855  	// Use length of strings for that.
  5856  	rlen := s.newValue2(subOp, types.Types[types.TINT], j, i)
  5857  	rcap := rlen
  5858  	if j != k && !t.IsString() {
  5859  		rcap = s.newValue2(subOp, types.Types[types.TINT], k, i)
  5860  	}
  5861  
  5862  	if (i.Op == ssa.OpConst64 || i.Op == ssa.OpConst32) && i.AuxInt == 0 {
  5863  		// No pointer arithmetic necessary.
  5864  		return ptr, rlen, rcap
  5865  	}
  5866  
  5867  	// Calculate the base pointer (rptr) for the new slice.
  5868  	//
  5869  	// Generate the following code assuming that indexes are in bounds.
  5870  	// The masking is to make sure that we don't generate a slice
  5871  	// that points to the next object in memory. We cannot just set
  5872  	// the pointer to nil because then we would create a nil slice or
  5873  	// string.
  5874  	//
  5875  	//     rcap = k - i
  5876  	//     rlen = j - i
  5877  	//     rptr = ptr + (mask(rcap) & (i * stride))
  5878  	//
  5879  	// Where mask(x) is 0 if x==0 and -1 if x>0 and stride is the width
  5880  	// of the element type.
  5881  	stride := s.constInt(types.Types[types.TINT], ptr.Type.Elem().Size())
  5882  
  5883  	// The delta is the number of bytes to offset ptr by.
  5884  	delta := s.newValue2(mulOp, types.Types[types.TINT], i, stride)
  5885  
  5886  	// If we're slicing to the point where the capacity is zero,
  5887  	// zero out the delta.
  5888  	mask := s.newValue1(ssa.OpSlicemask, types.Types[types.TINT], rcap)
  5889  	delta = s.newValue2(andOp, types.Types[types.TINT], delta, mask)
  5890  
  5891  	// Compute rptr = ptr + delta.
  5892  	rptr := s.newValue2(ssa.OpAddPtr, ptr.Type, ptr, delta)
  5893  
  5894  	return rptr, rlen, rcap
  5895  }
  5896  
  5897  type u642fcvtTab struct {
  5898  	leq, cvt2F, and, rsh, or, add ssa.Op
  5899  	one                           func(*state, *types.Type, int64) *ssa.Value
  5900  }
  5901  
  5902  var u64_f64 = u642fcvtTab{
  5903  	leq:   ssa.OpLeq64,
  5904  	cvt2F: ssa.OpCvt64to64F,
  5905  	and:   ssa.OpAnd64,
  5906  	rsh:   ssa.OpRsh64Ux64,
  5907  	or:    ssa.OpOr64,
  5908  	add:   ssa.OpAdd64F,
  5909  	one:   (*state).constInt64,
  5910  }
  5911  
  5912  var u64_f32 = u642fcvtTab{
  5913  	leq:   ssa.OpLeq64,
  5914  	cvt2F: ssa.OpCvt64to32F,
  5915  	and:   ssa.OpAnd64,
  5916  	rsh:   ssa.OpRsh64Ux64,
  5917  	or:    ssa.OpOr64,
  5918  	add:   ssa.OpAdd32F,
  5919  	one:   (*state).constInt64,
  5920  }
  5921  
  5922  func (s *state) uint64Tofloat64(n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  5923  	return s.uint64Tofloat(&u64_f64, n, x, ft, tt)
  5924  }
  5925  
  5926  func (s *state) uint64Tofloat32(n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  5927  	return s.uint64Tofloat(&u64_f32, n, x, ft, tt)
  5928  }
  5929  
  5930  func (s *state) uint64Tofloat(cvttab *u642fcvtTab, n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  5931  	// if x >= 0 {
  5932  	//    result = (floatY) x
  5933  	// } else {
  5934  	// 	  y = uintX(x) ; y = x & 1
  5935  	// 	  z = uintX(x) ; z = z >> 1
  5936  	// 	  z = z | y
  5937  	// 	  result = floatY(z)
  5938  	// 	  result = result + result
  5939  	// }
  5940  	//
  5941  	// Code borrowed from old code generator.
  5942  	// What's going on: large 64-bit "unsigned" looks like
  5943  	// negative number to hardware's integer-to-float
  5944  	// conversion. However, because the mantissa is only
  5945  	// 63 bits, we don't need the LSB, so instead we do an
  5946  	// unsigned right shift (divide by two), convert, and
  5947  	// double. However, before we do that, we need to be
  5948  	// sure that we do not lose a "1" if that made the
  5949  	// difference in the resulting rounding. Therefore, we
  5950  	// preserve it, and OR (not ADD) it back in. The case
  5951  	// that matters is when the eleven discarded bits are
  5952  	// equal to 10000000001; that rounds up, and the 1 cannot
  5953  	// be lost else it would round down if the LSB of the
  5954  	// candidate mantissa is 0.
  5955  
  5956  	cmp := s.newValue2(cvttab.leq, types.Types[types.TBOOL], s.zeroVal(ft), x)
  5957  
  5958  	b := s.endBlock()
  5959  	b.Kind = block.BlockIf
  5960  	b.SetControl(cmp)
  5961  	b.Likely = ssa.BranchLikely
  5962  
  5963  	bThen := s.f.NewBlock(block.BlockPlain)
  5964  	bElse := s.f.NewBlock(block.BlockPlain)
  5965  	bAfter := s.f.NewBlock(block.BlockPlain)
  5966  
  5967  	b.AddEdgeTo(bThen)
  5968  	s.startBlock(bThen)
  5969  	a0 := s.newValue1(cvttab.cvt2F, tt, x)
  5970  	s.vars[n] = a0
  5971  	s.endBlock()
  5972  	bThen.AddEdgeTo(bAfter)
  5973  
  5974  	b.AddEdgeTo(bElse)
  5975  	s.startBlock(bElse)
  5976  	one := cvttab.one(s, ft, 1)
  5977  	y := s.newValue2(cvttab.and, ft, x, one)
  5978  	z := s.newValue2(cvttab.rsh, ft, x, one)
  5979  	z = s.newValue2(cvttab.or, ft, z, y)
  5980  	a := s.newValue1(cvttab.cvt2F, tt, z)
  5981  	a1 := s.newValue2(cvttab.add, tt, a, a)
  5982  	s.vars[n] = a1
  5983  	s.endBlock()
  5984  	bElse.AddEdgeTo(bAfter)
  5985  
  5986  	s.startBlock(bAfter)
  5987  	return s.variable(n, n.Type())
  5988  }
  5989  
  5990  type u322fcvtTab struct {
  5991  	cvtI2F, cvtF2F ssa.Op
  5992  }
  5993  
  5994  var u32_f64 = u322fcvtTab{
  5995  	cvtI2F: ssa.OpCvt32to64F,
  5996  	cvtF2F: ssa.OpCopy,
  5997  }
  5998  
  5999  var u32_f32 = u322fcvtTab{
  6000  	cvtI2F: ssa.OpCvt32to32F,
  6001  	cvtF2F: ssa.OpCvt64Fto32F,
  6002  }
  6003  
  6004  func (s *state) uint32Tofloat64(n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  6005  	return s.uint32Tofloat(&u32_f64, n, x, ft, tt)
  6006  }
  6007  
  6008  func (s *state) uint32Tofloat32(n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  6009  	return s.uint32Tofloat(&u32_f32, n, x, ft, tt)
  6010  }
  6011  
  6012  func (s *state) uint32Tofloat(cvttab *u322fcvtTab, n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  6013  	// if x >= 0 {
  6014  	// 	result = floatY(x)
  6015  	// } else {
  6016  	// 	result = floatY(float64(x) + (1<<32))
  6017  	// }
  6018  	cmp := s.newValue2(ssa.OpLeq32, types.Types[types.TBOOL], s.zeroVal(ft), x)
  6019  	b := s.endBlock()
  6020  	b.Kind = block.BlockIf
  6021  	b.SetControl(cmp)
  6022  	b.Likely = ssa.BranchLikely
  6023  
  6024  	bThen := s.f.NewBlock(block.BlockPlain)
  6025  	bElse := s.f.NewBlock(block.BlockPlain)
  6026  	bAfter := s.f.NewBlock(block.BlockPlain)
  6027  
  6028  	b.AddEdgeTo(bThen)
  6029  	s.startBlock(bThen)
  6030  	a0 := s.newValue1(cvttab.cvtI2F, tt, x)
  6031  	s.vars[n] = a0
  6032  	s.endBlock()
  6033  	bThen.AddEdgeTo(bAfter)
  6034  
  6035  	b.AddEdgeTo(bElse)
  6036  	s.startBlock(bElse)
  6037  	a1 := s.newValue1(ssa.OpCvt32to64F, types.Types[types.TFLOAT64], x)
  6038  	twoToThe32 := s.constFloat64(types.Types[types.TFLOAT64], float64(1<<32))
  6039  	a2 := s.newValue2(ssa.OpAdd64F, types.Types[types.TFLOAT64], a1, twoToThe32)
  6040  	a3 := s.newValue1(cvttab.cvtF2F, tt, a2)
  6041  
  6042  	s.vars[n] = a3
  6043  	s.endBlock()
  6044  	bElse.AddEdgeTo(bAfter)
  6045  
  6046  	s.startBlock(bAfter)
  6047  	return s.variable(n, n.Type())
  6048  }
  6049  
  6050  // referenceTypeBuiltin generates code for the len/cap builtins for maps and channels.
  6051  func (s *state) referenceTypeBuiltin(n *ir.UnaryExpr, x *ssa.Value) *ssa.Value {
  6052  	if !n.X.Type().IsMap() && !n.X.Type().IsChan() {
  6053  		s.Fatalf("node must be a map or a channel")
  6054  	}
  6055  	if n.X.Type().IsChan() && n.Op() == ir.OLEN {
  6056  		s.Fatalf("cannot inline len(chan)") // must use runtime.chanlen now
  6057  	}
  6058  	if n.X.Type().IsChan() && n.Op() == ir.OCAP {
  6059  		s.Fatalf("cannot inline cap(chan)") // must use runtime.chancap now
  6060  	}
  6061  	if n.X.Type().IsMap() && n.Op() == ir.OCAP {
  6062  		s.Fatalf("cannot inline cap(map)") // cap(map) does not exist
  6063  	}
  6064  	// if n == nil {
  6065  	//   return 0
  6066  	// } else {
  6067  	//   // len, the actual loadType depends
  6068  	//   return int(*((*loadType)n))
  6069  	//   // cap (chan only, not used for now)
  6070  	//   return *(((*int)n)+1)
  6071  	// }
  6072  	lenType := n.Type()
  6073  	nilValue := s.constNil(types.Types[types.TUINTPTR])
  6074  	cmp := s.newValue2(ssa.OpEqPtr, types.Types[types.TBOOL], x, nilValue)
  6075  	b := s.endBlock()
  6076  	b.Kind = block.BlockIf
  6077  	b.SetControl(cmp)
  6078  	b.Likely = ssa.BranchUnlikely
  6079  
  6080  	bThen := s.f.NewBlock(block.BlockPlain)
  6081  	bElse := s.f.NewBlock(block.BlockPlain)
  6082  	bAfter := s.f.NewBlock(block.BlockPlain)
  6083  
  6084  	// length/capacity of a nil map/chan is zero
  6085  	b.AddEdgeTo(bThen)
  6086  	s.startBlock(bThen)
  6087  	s.vars[n] = s.zeroVal(lenType)
  6088  	s.endBlock()
  6089  	bThen.AddEdgeTo(bAfter)
  6090  
  6091  	b.AddEdgeTo(bElse)
  6092  	s.startBlock(bElse)
  6093  	switch n.Op() {
  6094  	case ir.OLEN:
  6095  		if n.X.Type().IsMap() {
  6096  			// length is stored in the first word, but needs conversion to int.
  6097  			loadType := reflectdata.MapType().Field(0).Type // uint64
  6098  			load := s.load(loadType, x)
  6099  			s.vars[n] = s.conv(nil, load, loadType, lenType) // integer conversion doesn't need Node
  6100  		} else {
  6101  			// length is stored in the first word for chan, no conversion needed.
  6102  			s.vars[n] = s.load(lenType, x)
  6103  		}
  6104  	case ir.OCAP:
  6105  		// capacity is stored in the second word for chan
  6106  		sw := s.newValue1I(ssa.OpOffPtr, lenType.PtrTo(), lenType.Size(), x)
  6107  		s.vars[n] = s.load(lenType, sw)
  6108  	default:
  6109  		s.Fatalf("op must be OLEN or OCAP")
  6110  	}
  6111  	s.endBlock()
  6112  	bElse.AddEdgeTo(bAfter)
  6113  
  6114  	s.startBlock(bAfter)
  6115  	return s.variable(n, lenType)
  6116  }
  6117  
  6118  type f2uCvtTab struct {
  6119  	ltf, cvt2U, subf, or ssa.Op
  6120  	floatValue           func(*state, *types.Type, float64) *ssa.Value
  6121  	intValue             func(*state, *types.Type, int64) *ssa.Value
  6122  	cutoff               uint64
  6123  }
  6124  
  6125  var f32_u64 = f2uCvtTab{
  6126  	ltf:        ssa.OpLess32F,
  6127  	cvt2U:      ssa.OpCvt32Fto64,
  6128  	subf:       ssa.OpSub32F,
  6129  	or:         ssa.OpOr64,
  6130  	floatValue: (*state).constFloat32,
  6131  	intValue:   (*state).constInt64,
  6132  	cutoff:     1 << 63,
  6133  }
  6134  
  6135  var f64_u64 = f2uCvtTab{
  6136  	ltf:        ssa.OpLess64F,
  6137  	cvt2U:      ssa.OpCvt64Fto64,
  6138  	subf:       ssa.OpSub64F,
  6139  	or:         ssa.OpOr64,
  6140  	floatValue: (*state).constFloat64,
  6141  	intValue:   (*state).constInt64,
  6142  	cutoff:     1 << 63,
  6143  }
  6144  
  6145  var f32_u32 = f2uCvtTab{
  6146  	ltf:        ssa.OpLess32F,
  6147  	cvt2U:      ssa.OpCvt32Fto32,
  6148  	subf:       ssa.OpSub32F,
  6149  	or:         ssa.OpOr32,
  6150  	floatValue: (*state).constFloat32,
  6151  	intValue:   func(s *state, t *types.Type, v int64) *ssa.Value { return s.constInt32(t, int32(v)) },
  6152  	cutoff:     1 << 31,
  6153  }
  6154  
  6155  var f64_u32 = f2uCvtTab{
  6156  	ltf:        ssa.OpLess64F,
  6157  	cvt2U:      ssa.OpCvt64Fto32,
  6158  	subf:       ssa.OpSub64F,
  6159  	or:         ssa.OpOr32,
  6160  	floatValue: (*state).constFloat64,
  6161  	intValue:   func(s *state, t *types.Type, v int64) *ssa.Value { return s.constInt32(t, int32(v)) },
  6162  	cutoff:     1 << 31,
  6163  }
  6164  
  6165  func (s *state) float32ToUint64(n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  6166  	return s.floatToUint(&f32_u64, n, x, ft, tt)
  6167  }
  6168  func (s *state) float64ToUint64(n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  6169  	return s.floatToUint(&f64_u64, n, x, ft, tt)
  6170  }
  6171  
  6172  func (s *state) float32ToUint32(n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  6173  	return s.floatToUint(&f32_u32, n, x, ft, tt)
  6174  }
  6175  
  6176  func (s *state) float64ToUint32(n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  6177  	return s.floatToUint(&f64_u32, n, x, ft, tt)
  6178  }
  6179  
  6180  func (s *state) floatToUint(cvttab *f2uCvtTab, n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  6181  	// cutoff:=1<<(intY_Size-1)
  6182  	// if x < floatX(cutoff) {
  6183  	// 	result = uintY(x) // bThen
  6184  	//  // gated by ConvertHash, clamp negative inputs to zero
  6185  	// 	if x < 0 { // unlikely
  6186  	// 		result = 0 // bZero
  6187  	// 	}
  6188  	// } else {
  6189  	// 	y = x - floatX(cutoff) // bElse
  6190  	// 	z = uintY(y)
  6191  	// 	result = z | -(cutoff)
  6192  	// }
  6193  
  6194  	cutoff := cvttab.floatValue(s, ft, float64(cvttab.cutoff))
  6195  	cmp := s.newValueOrSfCall2(cvttab.ltf, types.Types[types.TBOOL], x, cutoff)
  6196  	b := s.endBlock()
  6197  	b.Kind = block.BlockIf
  6198  	b.SetControl(cmp)
  6199  	b.Likely = ssa.BranchLikely
  6200  
  6201  	var bThen, bZero *ssa.Block
  6202  	// use salted hash to distinguish unsigned convert at a Pos from signed convert at a Pos
  6203  	newConversion := base.ConvertHash.MatchPosWithInfo(n.Pos(), "U", nil)
  6204  	if newConversion {
  6205  		bZero = s.f.NewBlock(block.BlockPlain)
  6206  		bThen = s.f.NewBlock(block.BlockIf)
  6207  	} else {
  6208  		bThen = s.f.NewBlock(block.BlockPlain)
  6209  	}
  6210  
  6211  	bElse := s.f.NewBlock(block.BlockPlain)
  6212  	bAfter := s.f.NewBlock(block.BlockPlain)
  6213  
  6214  	b.AddEdgeTo(bThen)
  6215  	s.startBlock(bThen)
  6216  	a0 := s.newValueOrSfCall1(cvttab.cvt2U, tt, x)
  6217  	s.vars[n] = a0
  6218  
  6219  	if newConversion {
  6220  		cmpz := s.newValueOrSfCall2(cvttab.ltf, types.Types[types.TBOOL], x, cvttab.floatValue(s, ft, 0.0))
  6221  		s.endBlock()
  6222  		bThen.SetControl(cmpz)
  6223  		bThen.AddEdgeTo(bZero)
  6224  		bThen.Likely = ssa.BranchUnlikely
  6225  		bThen.AddEdgeTo(bAfter)
  6226  
  6227  		s.startBlock(bZero)
  6228  		s.vars[n] = cvttab.intValue(s, tt, 0)
  6229  		s.endBlock()
  6230  		bZero.AddEdgeTo(bAfter)
  6231  	} else {
  6232  		s.endBlock()
  6233  		bThen.AddEdgeTo(bAfter)
  6234  	}
  6235  
  6236  	b.AddEdgeTo(bElse)
  6237  	s.startBlock(bElse)
  6238  	y := s.newValueOrSfCall2(cvttab.subf, ft, x, cutoff)
  6239  	y = s.newValueOrSfCall1(cvttab.cvt2U, tt, y)
  6240  	z := cvttab.intValue(s, tt, int64(-cvttab.cutoff))
  6241  	a1 := s.newValue2(cvttab.or, tt, y, z)
  6242  	s.vars[n] = a1
  6243  	s.endBlock()
  6244  	bElse.AddEdgeTo(bAfter)
  6245  
  6246  	s.startBlock(bAfter)
  6247  	return s.variable(n, n.Type())
  6248  }
  6249  
  6250  // dottype generates SSA for a type assertion node.
  6251  // commaok indicates whether to panic or return a bool.
  6252  // If commaok is false, resok will be nil.
  6253  func (s *state) dottype(n *ir.TypeAssertExpr, commaok bool) (res, resok *ssa.Value) {
  6254  	iface := s.expr(n.X)              // input interface
  6255  	target := s.reflectType(n.Type()) // target type
  6256  	var targetItab *ssa.Value
  6257  	if n.ITab != nil {
  6258  		targetItab = s.expr(n.ITab)
  6259  	}
  6260  
  6261  	if n.UseNilPanic {
  6262  		if commaok {
  6263  			base.Fatalf("unexpected *ir.TypeAssertExpr with UseNilPanic == true && commaok == true")
  6264  		}
  6265  		if n.Type().IsInterface() {
  6266  			// Currently we do not expect the compiler to emit type assertions with UseNilPanic, that asserts to an interface type.
  6267  			// If needed, this can be relaxed in the future, but for now we can't assert that.
  6268  			base.Fatalf("unexpected *ir.TypeAssertExpr with UseNilPanic == true && Type().IsInterface() == true")
  6269  		}
  6270  		typs := s.f.Config.Types
  6271  		iface = s.newValue2(
  6272  			ssa.OpIMake,
  6273  			iface.Type,
  6274  			s.nilCheck(s.newValue1(ssa.OpITab, typs.BytePtr, iface)),
  6275  			s.newValue1(ssa.OpIData, typs.BytePtr, iface),
  6276  		)
  6277  	}
  6278  
  6279  	return s.dottype1(n.Pos(), n.X.Type(), n.Type(), iface, nil, target, targetItab, commaok, n.Descriptor)
  6280  }
  6281  
  6282  func (s *state) dynamicDottype(n *ir.DynamicTypeAssertExpr, commaok bool) (res, resok *ssa.Value) {
  6283  	iface := s.expr(n.X)
  6284  	var source, target, targetItab *ssa.Value
  6285  	if n.SrcRType != nil {
  6286  		source = s.expr(n.SrcRType)
  6287  	}
  6288  	if !n.X.Type().IsEmptyInterface() && !n.Type().IsInterface() {
  6289  		byteptr := s.f.Config.Types.BytePtr
  6290  		targetItab = s.expr(n.ITab)
  6291  		// TODO(mdempsky): Investigate whether compiling n.RType could be
  6292  		// better than loading itab.typ.
  6293  		target = s.load(byteptr, s.newValue1I(ssa.OpOffPtr, byteptr, rttype.ITab.OffsetOf("Type"), targetItab))
  6294  	} else {
  6295  		target = s.expr(n.RType)
  6296  	}
  6297  	return s.dottype1(n.Pos(), n.X.Type(), n.Type(), iface, source, target, targetItab, commaok, nil)
  6298  }
  6299  
  6300  // dottype1 implements a x.(T) operation. iface is the argument (x), dst is the type we're asserting to (T)
  6301  // and src is the type we're asserting from.
  6302  // source is the *runtime._type of src
  6303  // target is the *runtime._type of dst.
  6304  // If src is a nonempty interface and dst is not an interface, targetItab is an itab representing (dst, src). Otherwise it is nil.
  6305  // commaok is true if the caller wants a boolean success value. Otherwise, the generated code panics if the conversion fails.
  6306  // descriptor is a compiler-allocated internal/abi.TypeAssert whose address is passed to runtime.typeAssert when
  6307  // the target type is a compile-time-known non-empty interface. It may be nil.
  6308  func (s *state) dottype1(pos src.XPos, src, dst *types.Type, iface, source, target, targetItab *ssa.Value, commaok bool, descriptor *obj.LSym) (res, resok *ssa.Value) {
  6309  	typs := s.f.Config.Types
  6310  	byteptr := typs.BytePtr
  6311  	if dst.IsInterface() {
  6312  		if dst.IsEmptyInterface() {
  6313  			// Converting to an empty interface.
  6314  			// Input could be an empty or nonempty interface.
  6315  			if base.Debug.TypeAssert > 0 {
  6316  				base.WarnfAt(pos, "type assertion inlined")
  6317  			}
  6318  
  6319  			// Get itab/type field from input.
  6320  			itab := s.newValue1(ssa.OpITab, byteptr, iface)
  6321  			// Conversion succeeds iff that field is not nil.
  6322  			cond := s.newValue2(ssa.OpNeqPtr, types.Types[types.TBOOL], itab, s.constNil(byteptr))
  6323  
  6324  			if src.IsEmptyInterface() && commaok {
  6325  				// Converting empty interface to empty interface with ,ok is just a nil check.
  6326  				return iface, cond
  6327  			}
  6328  
  6329  			// Branch on nilness.
  6330  			b := s.endBlock()
  6331  			b.Kind = block.BlockIf
  6332  			b.SetControl(cond)
  6333  			b.Likely = ssa.BranchLikely
  6334  			bOk := s.f.NewBlock(block.BlockPlain)
  6335  			bFail := s.f.NewBlock(block.BlockPlain)
  6336  			b.AddEdgeTo(bOk)
  6337  			b.AddEdgeTo(bFail)
  6338  
  6339  			if !commaok {
  6340  				// On failure, panic by calling panicnildottype.
  6341  				s.startBlock(bFail)
  6342  				s.rtcall(ir.Syms.Panicnildottype, false, nil, target)
  6343  
  6344  				// On success, return (perhaps modified) input interface.
  6345  				s.startBlock(bOk)
  6346  				if src.IsEmptyInterface() {
  6347  					res = iface // Use input interface unchanged.
  6348  					return
  6349  				}
  6350  				// Load type out of itab, build interface with existing idata.
  6351  				off := s.newValue1I(ssa.OpOffPtr, byteptr, rttype.ITab.OffsetOf("Type"), itab)
  6352  				typ := s.load(byteptr, off)
  6353  				idata := s.newValue1(ssa.OpIData, byteptr, iface)
  6354  				res = s.newValue2(ssa.OpIMake, dst, typ, idata)
  6355  				return
  6356  			}
  6357  
  6358  			s.startBlock(bOk)
  6359  			// nonempty -> empty
  6360  			// Need to load type from itab
  6361  			off := s.newValue1I(ssa.OpOffPtr, byteptr, rttype.ITab.OffsetOf("Type"), itab)
  6362  			s.vars[typVar] = s.load(byteptr, off)
  6363  			s.endBlock()
  6364  
  6365  			// itab is nil, might as well use that as the nil result.
  6366  			s.startBlock(bFail)
  6367  			s.vars[typVar] = itab
  6368  			s.endBlock()
  6369  
  6370  			// Merge point.
  6371  			bEnd := s.f.NewBlock(block.BlockPlain)
  6372  			bOk.AddEdgeTo(bEnd)
  6373  			bFail.AddEdgeTo(bEnd)
  6374  			s.startBlock(bEnd)
  6375  			idata := s.newValue1(ssa.OpIData, byteptr, iface)
  6376  			res = s.newValue2(ssa.OpIMake, dst, s.variable(typVar, byteptr), idata)
  6377  			resok = cond
  6378  			delete(s.vars, typVar) // no practical effect, just to indicate typVar is no longer live.
  6379  			return
  6380  		}
  6381  		// converting to a nonempty interface needs a runtime call.
  6382  		if base.Debug.TypeAssert > 0 {
  6383  			base.WarnfAt(pos, "type assertion not inlined")
  6384  		}
  6385  
  6386  		itab := s.newValue1(ssa.OpITab, byteptr, iface)
  6387  		data := s.newValue1(ssa.OpIData, types.Types[types.TUNSAFEPTR], iface)
  6388  
  6389  		// First, check for nil.
  6390  		bNil := s.f.NewBlock(block.BlockPlain)
  6391  		bNonNil := s.f.NewBlock(block.BlockPlain)
  6392  		bMerge := s.f.NewBlock(block.BlockPlain)
  6393  		cond := s.newValue2(ssa.OpNeqPtr, types.Types[types.TBOOL], itab, s.constNil(byteptr))
  6394  		b := s.endBlock()
  6395  		b.Kind = block.BlockIf
  6396  		b.SetControl(cond)
  6397  		b.Likely = ssa.BranchLikely
  6398  		b.AddEdgeTo(bNonNil)
  6399  		b.AddEdgeTo(bNil)
  6400  
  6401  		s.startBlock(bNil)
  6402  		if commaok {
  6403  			s.vars[typVar] = itab // which will be nil
  6404  			b := s.endBlock()
  6405  			b.AddEdgeTo(bMerge)
  6406  		} else {
  6407  			// Panic if input is nil.
  6408  			s.rtcall(ir.Syms.Panicnildottype, false, nil, target)
  6409  		}
  6410  
  6411  		// Get typ, possibly by loading out of itab.
  6412  		s.startBlock(bNonNil)
  6413  		typ := itab
  6414  		if !src.IsEmptyInterface() {
  6415  			typ = s.load(byteptr, s.newValue1I(ssa.OpOffPtr, byteptr, rttype.ITab.OffsetOf("Type"), itab))
  6416  		}
  6417  
  6418  		// Check the cache first.
  6419  		var d *ssa.Value
  6420  		if descriptor != nil {
  6421  			d = s.newValue1A(ssa.OpAddr, byteptr, descriptor, s.sb)
  6422  			if base.Flag.N == 0 && rtabi.UseInterfaceSwitchCache(Arch.LinkArch.Family) {
  6423  				// Note: we can only use the cache if we have the right atomic load instruction.
  6424  				// Double-check that here.
  6425  				if intrinsics.lookup(Arch.LinkArch.Arch, "internal/runtime/atomic", "Loadp") == nil {
  6426  					s.Fatalf("atomic load not available")
  6427  				}
  6428  				// Pick right size ops.
  6429  				var mul, and, add, zext ssa.Op
  6430  				if s.config.PtrSize == 4 {
  6431  					mul = ssa.OpMul32
  6432  					and = ssa.OpAnd32
  6433  					add = ssa.OpAdd32
  6434  					zext = ssa.OpCopy
  6435  				} else {
  6436  					mul = ssa.OpMul64
  6437  					and = ssa.OpAnd64
  6438  					add = ssa.OpAdd64
  6439  					zext = ssa.OpZeroExt32to64
  6440  				}
  6441  
  6442  				loopHead := s.f.NewBlock(block.BlockPlain)
  6443  				loopBody := s.f.NewBlock(block.BlockPlain)
  6444  				cacheHit := s.f.NewBlock(block.BlockPlain)
  6445  				cacheMiss := s.f.NewBlock(block.BlockPlain)
  6446  
  6447  				// Load cache pointer out of descriptor, with an atomic load so
  6448  				// we ensure that we see a fully written cache.
  6449  				atomicLoad := s.newValue2(ssa.OpAtomicLoadPtr, types.NewTuple(typs.BytePtr, types.TypeMem), d, s.mem())
  6450  				cache := s.newValue1(ssa.OpSelect0, typs.BytePtr, atomicLoad)
  6451  				s.vars[memVar] = s.newValue1(ssa.OpSelect1, types.TypeMem, atomicLoad)
  6452  
  6453  				// Load hash from type or itab.
  6454  				var hash *ssa.Value
  6455  				if src.IsEmptyInterface() {
  6456  					hash = s.newValue2(ssa.OpLoad, typs.UInt32, s.newValue1I(ssa.OpOffPtr, typs.UInt32Ptr, rttype.Type.OffsetOf("Hash"), typ), s.mem())
  6457  				} else {
  6458  					hash = s.newValue2(ssa.OpLoad, typs.UInt32, s.newValue1I(ssa.OpOffPtr, typs.UInt32Ptr, rttype.ITab.OffsetOf("Hash"), itab), s.mem())
  6459  				}
  6460  				hash = s.newValue1(zext, typs.Uintptr, hash)
  6461  				s.vars[hashVar] = hash
  6462  				// Load mask from cache.
  6463  				mask := s.newValue2(ssa.OpLoad, typs.Uintptr, cache, s.mem())
  6464  				// Jump to loop head.
  6465  				b := s.endBlock()
  6466  				b.AddEdgeTo(loopHead)
  6467  
  6468  				// At loop head, get pointer to the cache entry.
  6469  				//   e := &cache.Entries[hash&mask]
  6470  				s.startBlock(loopHead)
  6471  				idx := s.newValue2(and, typs.Uintptr, s.variable(hashVar, typs.Uintptr), mask)
  6472  				idx = s.newValue2(mul, typs.Uintptr, idx, s.uintptrConstant(uint64(2*s.config.PtrSize)))
  6473  				idx = s.newValue2(add, typs.Uintptr, idx, s.uintptrConstant(uint64(s.config.PtrSize)))
  6474  				e := s.newValue2(ssa.OpAddPtr, typs.UintptrPtr, cache, idx)
  6475  				//   hash++
  6476  				s.vars[hashVar] = s.newValue2(add, typs.Uintptr, s.variable(hashVar, typs.Uintptr), s.uintptrConstant(1))
  6477  
  6478  				// Look for a cache hit.
  6479  				//   if e.Typ == typ { goto hit }
  6480  				eTyp := s.newValue2(ssa.OpLoad, typs.Uintptr, e, s.mem())
  6481  				cmp1 := s.newValue2(ssa.OpEqPtr, typs.Bool, typ, eTyp)
  6482  				b = s.endBlock()
  6483  				b.Kind = block.BlockIf
  6484  				b.SetControl(cmp1)
  6485  				b.AddEdgeTo(cacheHit)
  6486  				b.AddEdgeTo(loopBody)
  6487  
  6488  				// Look for an empty entry, the tombstone for this hash table.
  6489  				//   if e.Typ == nil { goto miss }
  6490  				s.startBlock(loopBody)
  6491  				cmp2 := s.newValue2(ssa.OpEqPtr, typs.Bool, eTyp, s.constNil(typs.BytePtr))
  6492  				b = s.endBlock()
  6493  				b.Kind = block.BlockIf
  6494  				b.SetControl(cmp2)
  6495  				b.AddEdgeTo(cacheMiss)
  6496  				b.AddEdgeTo(loopHead)
  6497  
  6498  				// On a hit, load the data fields of the cache entry.
  6499  				//   Itab = e.Itab
  6500  				s.startBlock(cacheHit)
  6501  				eItab := s.newValue2(ssa.OpLoad, typs.BytePtr, s.newValue1I(ssa.OpOffPtr, typs.BytePtrPtr, s.config.PtrSize, e), s.mem())
  6502  				s.vars[typVar] = eItab
  6503  				b = s.endBlock()
  6504  				b.AddEdgeTo(bMerge)
  6505  
  6506  				// On a miss, call into the runtime to get the answer.
  6507  				s.startBlock(cacheMiss)
  6508  			}
  6509  		}
  6510  
  6511  		// Call into runtime to get itab for result.
  6512  		if descriptor != nil {
  6513  			itab = s.rtcall(ir.Syms.TypeAssert, true, []*types.Type{byteptr}, d, typ)[0]
  6514  		} else {
  6515  			var fn *obj.LSym
  6516  			if commaok {
  6517  				fn = ir.Syms.AssertE2I2
  6518  			} else {
  6519  				fn = ir.Syms.AssertE2I
  6520  			}
  6521  			itab = s.rtcall(fn, true, []*types.Type{byteptr}, target, typ)[0]
  6522  		}
  6523  		s.vars[typVar] = itab
  6524  		b = s.endBlock()
  6525  		b.AddEdgeTo(bMerge)
  6526  
  6527  		// Build resulting interface.
  6528  		s.startBlock(bMerge)
  6529  		itab = s.variable(typVar, byteptr)
  6530  		var ok *ssa.Value
  6531  		if commaok {
  6532  			ok = s.newValue2(ssa.OpNeqPtr, types.Types[types.TBOOL], itab, s.constNil(byteptr))
  6533  		}
  6534  		return s.newValue2(ssa.OpIMake, dst, itab, data), ok
  6535  	}
  6536  
  6537  	if base.Debug.TypeAssert > 0 {
  6538  		base.WarnfAt(pos, "type assertion inlined")
  6539  	}
  6540  
  6541  	// Converting to a concrete type.
  6542  	direct := types.IsDirectIface(dst)
  6543  	itab := s.newValue1(ssa.OpITab, byteptr, iface) // type word of interface
  6544  	if base.Debug.TypeAssert > 0 {
  6545  		base.WarnfAt(pos, "type assertion inlined")
  6546  	}
  6547  	var wantedFirstWord *ssa.Value
  6548  	if src.IsEmptyInterface() {
  6549  		// Looking for pointer to target type.
  6550  		wantedFirstWord = target
  6551  	} else {
  6552  		// Looking for pointer to itab for target type and source interface.
  6553  		wantedFirstWord = targetItab
  6554  	}
  6555  
  6556  	var tmp ir.Node     // temporary for use with large types
  6557  	var addr *ssa.Value // address of tmp
  6558  	if commaok && !ssa.CanSSA(dst) {
  6559  		// unSSAable type, use temporary.
  6560  		// TODO: get rid of some of these temporaries.
  6561  		tmp, addr = s.temp(pos, dst)
  6562  	}
  6563  
  6564  	cond := s.newValue2(ssa.OpEqPtr, types.Types[types.TBOOL], itab, wantedFirstWord)
  6565  	b := s.endBlock()
  6566  	b.Kind = block.BlockIf
  6567  	b.SetControl(cond)
  6568  	b.Likely = ssa.BranchLikely
  6569  
  6570  	bOk := s.f.NewBlock(block.BlockPlain)
  6571  	bFail := s.f.NewBlock(block.BlockPlain)
  6572  	b.AddEdgeTo(bOk)
  6573  	b.AddEdgeTo(bFail)
  6574  
  6575  	if !commaok {
  6576  		// on failure, panic by calling panicdottype
  6577  		s.startBlock(bFail)
  6578  		taddr := source
  6579  		if taddr == nil {
  6580  			taddr = s.reflectType(src)
  6581  		}
  6582  		if src.IsEmptyInterface() {
  6583  			s.rtcall(ir.Syms.PanicdottypeE, false, nil, itab, target, taddr)
  6584  		} else {
  6585  			s.rtcall(ir.Syms.PanicdottypeI, false, nil, itab, target, taddr)
  6586  		}
  6587  
  6588  		// on success, return data from interface
  6589  		s.startBlock(bOk)
  6590  		if direct {
  6591  			return s.newValue1(ssa.OpIData, dst, iface), nil
  6592  		}
  6593  		p := s.newValue1(ssa.OpIData, types.NewPtr(dst), iface)
  6594  		return s.load(dst, p), nil
  6595  	}
  6596  
  6597  	// commaok is the more complicated case because we have
  6598  	// a control flow merge point.
  6599  	bEnd := s.f.NewBlock(block.BlockPlain)
  6600  	// Note that we need a new valVar each time (unlike okVar where we can
  6601  	// reuse the variable) because it might have a different type every time.
  6602  	valVar := ssaMarker("val")
  6603  
  6604  	// type assertion succeeded
  6605  	s.startBlock(bOk)
  6606  	if tmp == nil {
  6607  		if direct {
  6608  			s.vars[valVar] = s.newValue1(ssa.OpIData, dst, iface)
  6609  		} else {
  6610  			p := s.newValue1(ssa.OpIData, types.NewPtr(dst), iface)
  6611  			s.vars[valVar] = s.load(dst, p)
  6612  		}
  6613  	} else {
  6614  		p := s.newValue1(ssa.OpIData, types.NewPtr(dst), iface)
  6615  		s.move(dst, addr, p)
  6616  	}
  6617  	s.vars[okVar] = s.constBool(true)
  6618  	s.endBlock()
  6619  	bOk.AddEdgeTo(bEnd)
  6620  
  6621  	// type assertion failed
  6622  	s.startBlock(bFail)
  6623  	if tmp == nil {
  6624  		s.vars[valVar] = s.zeroVal(dst)
  6625  	} else {
  6626  		s.zero(dst, addr)
  6627  	}
  6628  	s.vars[okVar] = s.constBool(false)
  6629  	s.endBlock()
  6630  	bFail.AddEdgeTo(bEnd)
  6631  
  6632  	// merge point
  6633  	s.startBlock(bEnd)
  6634  	if tmp == nil {
  6635  		res = s.variable(valVar, dst)
  6636  		delete(s.vars, valVar) // no practical effect, just to indicate typVar is no longer live.
  6637  	} else {
  6638  		res = s.load(dst, addr)
  6639  	}
  6640  	resok = s.variable(okVar, types.Types[types.TBOOL])
  6641  	delete(s.vars, okVar) // ditto
  6642  	return res, resok
  6643  }
  6644  
  6645  // temp allocates a temp of type t at position pos
  6646  func (s *state) temp(pos src.XPos, t *types.Type) (*ir.Name, *ssa.Value) {
  6647  	tmp := typecheck.TempAt(pos, s.curfn, t)
  6648  	if t.HasPointers() || (ssa.IsMergeCandidate(tmp) && t != deferstruct()) {
  6649  		s.vars[memVar] = s.newValue1A(ssa.OpVarDef, types.TypeMem, tmp, s.mem())
  6650  	}
  6651  	addr := s.addr(tmp)
  6652  	return tmp, addr
  6653  }
  6654  
  6655  // variable returns the value of a variable at the current location.
  6656  func (s *state) variable(n ir.Node, t *types.Type) *ssa.Value {
  6657  	v := s.vars[n]
  6658  	if v != nil {
  6659  		return v
  6660  	}
  6661  	v = s.fwdVars[n]
  6662  	if v != nil {
  6663  		return v
  6664  	}
  6665  
  6666  	if s.curBlock == s.f.Entry {
  6667  		// No variable should be live at entry.
  6668  		s.f.Fatalf("value %v (%v) incorrectly live at entry", n, v)
  6669  	}
  6670  	// Make a FwdRef, which records a value that's live on block input.
  6671  	// We'll find the matching definition as part of insertPhis.
  6672  	v = s.newValue0A(ssa.OpFwdRef, t, fwdRefAux{N: n})
  6673  	s.fwdVars[n] = v
  6674  	if n.Op() == ir.ONAME {
  6675  		s.addNamedValue(n.(*ir.Name), v)
  6676  	}
  6677  	return v
  6678  }
  6679  
  6680  func (s *state) mem() *ssa.Value {
  6681  	return s.variable(memVar, types.TypeMem)
  6682  }
  6683  
  6684  func (s *state) addNamedValue(n *ir.Name, v *ssa.Value) {
  6685  	if n.Class == ir.Pxxx {
  6686  		// Don't track our marker nodes (memVar etc.).
  6687  		return
  6688  	}
  6689  	if ir.IsAutoTmp(n) {
  6690  		// Don't track temporary variables.
  6691  		return
  6692  	}
  6693  	if n.Class == ir.PPARAMOUT {
  6694  		// Don't track named output values.  This prevents return values
  6695  		// from being assigned too early. See #14591 and #14762. TODO: allow this.
  6696  		return
  6697  	}
  6698  	loc := ssa.LocalSlot{N: n, Type: n.Type(), Off: 0}
  6699  	values, ok := s.f.NamedValues[loc]
  6700  	if !ok {
  6701  		s.f.Names = append(s.f.Names, loc)
  6702  	}
  6703  	s.f.NamedValues[loc] = append(values, v)
  6704  }
  6705  
  6706  // Branch is an unresolved branch.
  6707  type Branch struct {
  6708  	P *obj.Prog  // branch instruction
  6709  	B *ssa.Block // target
  6710  }
  6711  
  6712  // State contains state needed during Prog generation.
  6713  type State struct {
  6714  	ABI obj.ABI
  6715  
  6716  	pp *objw.Progs
  6717  
  6718  	// Branches remembers all the branch instructions we've seen
  6719  	// and where they would like to go.
  6720  	Branches []Branch
  6721  
  6722  	// JumpTables remembers all the jump tables we've seen.
  6723  	JumpTables []*ssa.Block
  6724  
  6725  	// bstart remembers where each block starts (indexed by block ID)
  6726  	bstart []*obj.Prog
  6727  
  6728  	maxarg int64 // largest frame size for arguments to calls made by the function
  6729  
  6730  	// Map from GC safe points to liveness index, generated by
  6731  	// liveness analysis.
  6732  	livenessMap liveness.Map
  6733  
  6734  	// partLiveArgs includes arguments that may be partially live, for which we
  6735  	// need to generate instructions that spill the argument registers.
  6736  	partLiveArgs map[*ir.Name]bool
  6737  
  6738  	// lineRunStart records the beginning of the current run of instructions
  6739  	// within a single block sharing the same line number
  6740  	// Used to move statement marks to the beginning of such runs.
  6741  	lineRunStart *obj.Prog
  6742  
  6743  	// wasm: The number of values on the WebAssembly stack. This is only used as a safeguard.
  6744  	OnWasmStackSkipped int
  6745  }
  6746  
  6747  func (s *State) FuncInfo() *obj.FuncInfo {
  6748  	return s.pp.CurFunc.LSym.Func()
  6749  }
  6750  
  6751  // Prog appends a new Prog.
  6752  func (s *State) Prog(as obj.As) *obj.Prog {
  6753  	p := s.pp.Prog(as)
  6754  	if objw.LosesStmtMark(as) {
  6755  		return p
  6756  	}
  6757  	// Float a statement start to the beginning of any same-line run.
  6758  	// lineRunStart is reset at block boundaries, which appears to work well.
  6759  	if s.lineRunStart == nil || s.lineRunStart.Pos.Line() != p.Pos.Line() {
  6760  		s.lineRunStart = p
  6761  	} else if p.Pos.IsStmt() == src.PosIsStmt {
  6762  		s.lineRunStart.Pos = s.lineRunStart.Pos.WithIsStmt()
  6763  		p.Pos = p.Pos.WithNotStmt()
  6764  	}
  6765  	return p
  6766  }
  6767  
  6768  // Pc returns the current Prog.
  6769  func (s *State) Pc() *obj.Prog {
  6770  	return s.pp.Next
  6771  }
  6772  
  6773  // SetPos sets the current source position.
  6774  func (s *State) SetPos(pos src.XPos) {
  6775  	s.pp.Pos = pos
  6776  }
  6777  
  6778  // Br emits a single branch instruction and returns the instruction.
  6779  // Not all architectures need the returned instruction, but otherwise
  6780  // the boilerplate is common to all.
  6781  func (s *State) Br(op obj.As, target *ssa.Block) *obj.Prog {
  6782  	p := s.Prog(op)
  6783  	p.To.Type = obj.TYPE_BRANCH
  6784  	s.Branches = append(s.Branches, Branch{P: p, B: target})
  6785  	return p
  6786  }
  6787  
  6788  // DebugFriendlySetPosFrom adjusts Pos.IsStmt subject to heuristics
  6789  // that reduce "jumpy" line number churn when debugging.
  6790  // Spill/fill/copy instructions from the register allocator,
  6791  // phi functions, and instructions with a no-pos position
  6792  // are examples of instructions that can cause churn.
  6793  func (s *State) DebugFriendlySetPosFrom(v *ssa.Value) {
  6794  	switch v.Op {
  6795  	case ssa.OpPhi, ssa.OpCopy, ssa.OpLoadReg, ssa.OpStoreReg:
  6796  		// These are not statements
  6797  		s.SetPos(v.Pos.WithNotStmt())
  6798  	default:
  6799  		p := v.Pos
  6800  		if p != src.NoXPos {
  6801  			// If the position is defined, update the position.
  6802  			// Also convert default IsStmt to NotStmt; only
  6803  			// explicit statement boundaries should appear
  6804  			// in the generated code.
  6805  			if p.IsStmt() != src.PosIsStmt {
  6806  				if s.pp.Pos.IsStmt() == src.PosIsStmt && s.pp.Pos.SameFileAndLine(p) {
  6807  					// If s.pp.Pos already has a statement mark, then it was set here (below) for
  6808  					// the previous value.  If an actual instruction had been emitted for that
  6809  					// value, then the statement mark would have been reset.  Since the statement
  6810  					// mark of s.pp.Pos was not reset, this position (file/line) still needs a
  6811  					// statement mark on an instruction.  If file and line for this value are
  6812  					// the same as the previous value, then the first instruction for this
  6813  					// value will work to take the statement mark.  Return early to avoid
  6814  					// resetting the statement mark.
  6815  					//
  6816  					// The reset of s.pp.Pos occurs in (*Progs).Prog() -- if it emits
  6817  					// an instruction, and the instruction's statement mark was set,
  6818  					// and it is not one of the LosesStmtMark instructions,
  6819  					// then Prog() resets the statement mark on the (*Progs).Pos.
  6820  					return
  6821  				}
  6822  				p = p.WithNotStmt()
  6823  				// Calls use the pos attached to v, but copy the statement mark from State
  6824  			}
  6825  			s.SetPos(p)
  6826  		} else {
  6827  			s.SetPos(s.pp.Pos.WithNotStmt())
  6828  		}
  6829  	}
  6830  }
  6831  
  6832  // emit argument info (locations on stack) for traceback.
  6833  func emitArgInfo(e *ssafn, f *ssa.Func, pp *objw.Progs) {
  6834  	ft := e.curfn.Type()
  6835  	if ft.NumRecvs() == 0 && ft.NumParams() == 0 {
  6836  		return
  6837  	}
  6838  
  6839  	x := EmitArgInfo(e.curfn, f.OwnAux.ABIInfo())
  6840  	x.Set(obj.AttrContentAddressable, true)
  6841  	e.curfn.LSym.Func().ArgInfo = x
  6842  
  6843  	// Emit a funcdata pointing at the arg info data.
  6844  	p := pp.Prog(obj.AFUNCDATA)
  6845  	p.From.SetConst(rtabi.FUNCDATA_ArgInfo)
  6846  	p.To.Type = obj.TYPE_MEM
  6847  	p.To.Name = obj.NAME_EXTERN
  6848  	p.To.Sym = x
  6849  }
  6850  
  6851  // emit argument info (locations on stack) of f for traceback.
  6852  func EmitArgInfo(f *ir.Func, abiInfo *abi.ABIParamResultInfo) *obj.LSym {
  6853  	x := base.Ctxt.Lookup(fmt.Sprintf("%s.arginfo%d", f.LSym.Name, f.ABI))
  6854  	x.Align = 1
  6855  	// NOTE: do not set ContentAddressable here. This may be referenced from
  6856  	// assembly code by name (in this case f is a declaration).
  6857  	// Instead, set it in emitArgInfo above.
  6858  
  6859  	PtrSize := int64(types.PtrSize)
  6860  	uintptrTyp := types.Types[types.TUINTPTR]
  6861  
  6862  	isAggregate := func(t *types.Type) bool {
  6863  		return isStructNotSIMD(t) || t.IsArray() || t.IsComplex() || t.IsInterface() || t.IsString() || t.IsSlice()
  6864  	}
  6865  
  6866  	wOff := 0
  6867  	n := 0
  6868  	writebyte := func(o uint8) { wOff = objw.Uint8(x, wOff, o) }
  6869  
  6870  	// Write one non-aggregate arg/field/element.
  6871  	write1 := func(sz, offset int64) {
  6872  		if offset >= rtabi.TraceArgsSpecial {
  6873  			writebyte(rtabi.TraceArgsOffsetTooLarge)
  6874  		} else {
  6875  			writebyte(uint8(offset))
  6876  			writebyte(uint8(sz))
  6877  		}
  6878  		n++
  6879  	}
  6880  
  6881  	// Visit t recursively and write it out.
  6882  	// Returns whether to continue visiting.
  6883  	var visitType func(baseOffset int64, t *types.Type, depth int) bool
  6884  	visitType = func(baseOffset int64, t *types.Type, depth int) bool {
  6885  		if n >= rtabi.TraceArgsLimit {
  6886  			writebyte(rtabi.TraceArgsDotdotdot)
  6887  			return false
  6888  		}
  6889  		if !isAggregate(t) {
  6890  			write1(t.Size(), baseOffset)
  6891  			return true
  6892  		}
  6893  		writebyte(rtabi.TraceArgsStartAgg)
  6894  		depth++
  6895  		if depth >= rtabi.TraceArgsMaxDepth {
  6896  			writebyte(rtabi.TraceArgsDotdotdot)
  6897  			writebyte(rtabi.TraceArgsEndAgg)
  6898  			n++
  6899  			return true
  6900  		}
  6901  		switch {
  6902  		case t.IsInterface(), t.IsString():
  6903  			_ = visitType(baseOffset, uintptrTyp, depth) &&
  6904  				visitType(baseOffset+PtrSize, uintptrTyp, depth)
  6905  		case t.IsSlice():
  6906  			_ = visitType(baseOffset, uintptrTyp, depth) &&
  6907  				visitType(baseOffset+PtrSize, uintptrTyp, depth) &&
  6908  				visitType(baseOffset+PtrSize*2, uintptrTyp, depth)
  6909  		case t.IsComplex():
  6910  			_ = visitType(baseOffset, types.FloatForComplex(t), depth) &&
  6911  				visitType(baseOffset+t.Size()/2, types.FloatForComplex(t), depth)
  6912  		case t.IsArray():
  6913  			if t.NumElem() == 0 {
  6914  				n++ // {} counts as a component
  6915  				break
  6916  			}
  6917  			for i := int64(0); i < t.NumElem(); i++ {
  6918  				if !visitType(baseOffset, t.Elem(), depth) {
  6919  					break
  6920  				}
  6921  				baseOffset += t.Elem().Size()
  6922  			}
  6923  		case isStructNotSIMD(t):
  6924  			if t.NumFields() == 0 {
  6925  				n++ // {} counts as a component
  6926  				break
  6927  			}
  6928  			for _, field := range t.Fields() {
  6929  				if !visitType(baseOffset+field.Offset, field.Type, depth) {
  6930  					break
  6931  				}
  6932  			}
  6933  		}
  6934  		writebyte(rtabi.TraceArgsEndAgg)
  6935  		return true
  6936  	}
  6937  
  6938  	start := 0
  6939  	if strings.Contains(f.LSym.Name, "[") {
  6940  		// Skip the dictionary argument - it is implicit and the user doesn't need to see it.
  6941  		start = 1
  6942  	}
  6943  
  6944  	for _, a := range abiInfo.InParams()[start:] {
  6945  		if !visitType(a.FrameOffset(abiInfo), a.Type, 0) {
  6946  			break
  6947  		}
  6948  	}
  6949  	writebyte(rtabi.TraceArgsEndSeq)
  6950  	if wOff > rtabi.TraceArgsMaxLen {
  6951  		base.Fatalf("ArgInfo too large")
  6952  	}
  6953  
  6954  	return x
  6955  }
  6956  
  6957  // for wrapper, emit info of wrapped function.
  6958  func emitWrappedFuncInfo(e *ssafn, pp *objw.Progs) {
  6959  	if base.Ctxt.Flag_linkshared {
  6960  		// Relative reference (SymPtrOff) to another shared object doesn't work.
  6961  		// Unfortunate.
  6962  		return
  6963  	}
  6964  
  6965  	wfn := e.curfn.WrappedFunc
  6966  	if wfn == nil {
  6967  		return
  6968  	}
  6969  
  6970  	wsym := wfn.Linksym()
  6971  	x := base.Ctxt.LookupInit(fmt.Sprintf("%s.wrapinfo", wsym.Name), func(x *obj.LSym) {
  6972  		objw.SymPtrOff(x, 0, wsym)
  6973  		x.Set(obj.AttrContentAddressable, true)
  6974  		x.Align = 4
  6975  	})
  6976  	e.curfn.LSym.Func().WrapInfo = x
  6977  
  6978  	// Emit a funcdata pointing at the wrap info data.
  6979  	p := pp.Prog(obj.AFUNCDATA)
  6980  	p.From.SetConst(rtabi.FUNCDATA_WrapInfo)
  6981  	p.To.Type = obj.TYPE_MEM
  6982  	p.To.Name = obj.NAME_EXTERN
  6983  	p.To.Sym = x
  6984  }
  6985  
  6986  // genssa appends entries to pp for each instruction in f.
  6987  func genssa(htmlWriter *ssa.HTMLWriter, f *ssa.Func, pp *objw.Progs) {
  6988  	var s State
  6989  	s.ABI = f.OwnAux.Fn.ABI()
  6990  
  6991  	e := f.Frontend().(*ssafn)
  6992  
  6993  	gatherPrintInfo := f.PrintOrHtmlSSA || ssaconfig.GenssaDump[f.Name]
  6994  
  6995  	var lv *liveness.Liveness
  6996  	s.livenessMap, s.partLiveArgs, lv = liveness.Compute(e.curfn, f, e.stkptrsize, pp, gatherPrintInfo)
  6997  	emitArgInfo(e, f, pp)
  6998  	argLiveBlockMap, argLiveValueMap := liveness.ArgLiveness(e.curfn, f, pp)
  6999  
  7000  	openDeferInfo := e.curfn.LSym.Func().OpenCodedDeferInfo
  7001  	if openDeferInfo != nil {
  7002  		// This function uses open-coded defers -- write out the funcdata
  7003  		// info that we computed at the end of genssa.
  7004  		p := pp.Prog(obj.AFUNCDATA)
  7005  		p.From.SetConst(rtabi.FUNCDATA_OpenCodedDeferInfo)
  7006  		p.To.Type = obj.TYPE_MEM
  7007  		p.To.Name = obj.NAME_EXTERN
  7008  		p.To.Sym = openDeferInfo
  7009  	}
  7010  
  7011  	emitWrappedFuncInfo(e, pp)
  7012  
  7013  	// Remember where each block starts.
  7014  	s.bstart = make([]*obj.Prog, f.NumBlocks())
  7015  	s.pp = pp
  7016  	var progToValue map[*obj.Prog]*ssa.Value
  7017  	var progToBlock map[*obj.Prog]*ssa.Block
  7018  	var valueToProgAfter []*obj.Prog // The first Prog following computation of a value v; v is visible at this point.
  7019  	if gatherPrintInfo {
  7020  		progToValue = make(map[*obj.Prog]*ssa.Value, f.NumValues())
  7021  		progToBlock = make(map[*obj.Prog]*ssa.Block, f.NumBlocks())
  7022  		f.Logf("genssa %s\n", f.Name)
  7023  		progToBlock[s.pp.Next] = f.Blocks[0]
  7024  	}
  7025  
  7026  	if base.Ctxt.Flag_locationlists {
  7027  		if cap(f.Cache.ValueToProgAfter) < f.NumValues() {
  7028  			f.Cache.ValueToProgAfter = make([]*obj.Prog, f.NumValues())
  7029  		}
  7030  		valueToProgAfter = f.Cache.ValueToProgAfter[:f.NumValues()]
  7031  		clear(valueToProgAfter)
  7032  	}
  7033  
  7034  	// If the very first instruction is not tagged as a statement,
  7035  	// debuggers may attribute it to previous function in program.
  7036  	firstPos := src.NoXPos
  7037  	for _, v := range f.Entry.Values {
  7038  		if v.Pos.IsStmt() == src.PosIsStmt && v.Op != ssa.OpArg && v.Op != ssa.OpArgIntReg && v.Op != ssa.OpArgFloatReg && v.Op != ssa.OpLoadReg && v.Op != ssa.OpStoreReg {
  7039  			firstPos = v.Pos
  7040  			v.Pos = firstPos.WithDefaultStmt()
  7041  			break
  7042  		}
  7043  	}
  7044  
  7045  	// inlMarks has an entry for each Prog that implements an inline mark.
  7046  	// It maps from that Prog to the global inlining id of the inlined body
  7047  	// which should unwind to this Prog's location.
  7048  	var inlMarks map[*obj.Prog]int32
  7049  	var inlMarkList []*obj.Prog
  7050  
  7051  	// inlMarksByPos maps from a (column 1) source position to the set of
  7052  	// Progs that are in the set above and have that source position.
  7053  	var inlMarksByPos map[src.XPos][]*obj.Prog
  7054  
  7055  	var argLiveIdx int = -1 // argument liveness info index
  7056  
  7057  	// These control cache line alignment; if the required portion of
  7058  	// a cache line is not available, then pad to obtain cache line
  7059  	// alignment.  Not implemented on all architectures, may not be
  7060  	// useful on all architectures.
  7061  	var hotAlign, hotRequire int64
  7062  
  7063  	if base.Debug.AlignHot > 0 {
  7064  		switch base.Ctxt.Arch.Name {
  7065  		// enable this on a case-by-case basis, with benchmarking.
  7066  		// currently shown:
  7067  		//   good for amd64
  7068  		//   not helpful for Apple Silicon
  7069  		//
  7070  		case "amd64", "386":
  7071  			// Align to 64 if 31 or fewer bytes remain in a cache line
  7072  			// benchmarks a little better than always aligning, and also
  7073  			// adds slightly less to the (PGO-compiled) binary size.
  7074  			hotAlign = 64
  7075  			hotRequire = 31
  7076  		}
  7077  	}
  7078  
  7079  	// Emit basic blocks
  7080  	for i, b := range f.Blocks {
  7081  
  7082  		s.lineRunStart = nil
  7083  		s.SetPos(s.pp.Pos.WithNotStmt()) // It needs a non-empty Pos, but cannot be a statement boundary (yet).
  7084  
  7085  		if hotAlign > 0 && b.Hotness&ssa.HotPgoInitial == ssa.HotPgoInitial {
  7086  			// So far this has only been shown profitable for PGO-hot loop headers.
  7087  			// The Hotness values allows distinctions between initial blocks that are "hot" or not, and "flow-in" or not.
  7088  			// Currently only the initial blocks of loops are tagged in this way;
  7089  			// there are no blocks tagged "pgo-hot" that are not also tagged "initial".
  7090  			// TODO more heuristics, more architectures.
  7091  			p := s.pp.Prog(obj.APCALIGNMAX)
  7092  			p.From.SetConst(hotAlign)
  7093  			p.To.SetConst(hotRequire)
  7094  		}
  7095  
  7096  		s.bstart[b.ID] = s.pp.Next
  7097  
  7098  		if idx, ok := argLiveBlockMap[b.ID]; ok && idx != argLiveIdx {
  7099  			argLiveIdx = idx
  7100  			p := s.pp.Prog(obj.APCDATA)
  7101  			p.From.SetConst(rtabi.PCDATA_ArgLiveIndex)
  7102  			p.To.SetConst(int64(idx))
  7103  		}
  7104  
  7105  		// Emit values in block
  7106  		Arch.SSAMarkMoves(&s, b)
  7107  		for _, v := range b.Values {
  7108  			x := s.pp.Next
  7109  			s.DebugFriendlySetPosFrom(v)
  7110  
  7111  			if v.Op.ResultInArg0() && v.ResultReg() != v.Args[0].Reg() {
  7112  				v.Fatalf("input[0] and output not in same register %s", v.LongString())
  7113  			}
  7114  
  7115  			switch v.Op {
  7116  			case ssa.OpInitMem:
  7117  				// memory arg needs no code
  7118  			case ssa.OpArg:
  7119  				// input args need no code
  7120  			case ssa.OpSP, ssa.OpSB:
  7121  				// nothing to do
  7122  			case ssa.OpSelect0, ssa.OpSelect1, ssa.OpSelectN, ssa.OpMakeResult:
  7123  				// nothing to do
  7124  			case ssa.OpGetG:
  7125  				// nothing to do when there's a g register,
  7126  				// and checkLower complains if there's not
  7127  			case ssa.OpVarDef, ssa.OpVarLive, ssa.OpKeepAlive, ssa.OpWBend:
  7128  				// nothing to do; already used by liveness
  7129  			case ssa.OpPhi:
  7130  				CheckLoweredPhi(v)
  7131  			case ssa.OpConvert:
  7132  				// nothing to do; no-op conversion for liveness
  7133  				if v.Args[0].Reg() != v.Reg() {
  7134  					v.Fatalf("OpConvert should be a no-op: %s; %s", v.Args[0].LongString(), v.LongString())
  7135  				}
  7136  			case ssa.OpInlMark:
  7137  				p := Arch.Ginsnop(s.pp)
  7138  				if inlMarks == nil {
  7139  					inlMarks = map[*obj.Prog]int32{}
  7140  					inlMarksByPos = map[src.XPos][]*obj.Prog{}
  7141  				}
  7142  				inlMarks[p] = v.AuxInt32()
  7143  				inlMarkList = append(inlMarkList, p)
  7144  				pos := v.Pos.AtColumn1()
  7145  				inlMarksByPos[pos] = append(inlMarksByPos[pos], p)
  7146  				firstPos = src.NoXPos
  7147  
  7148  			default:
  7149  				// Special case for first line in function; move it to the start (which cannot be a register-valued instruction)
  7150  				if firstPos != src.NoXPos && v.Op != ssa.OpArgIntReg && v.Op != ssa.OpArgFloatReg && v.Op != ssa.OpLoadReg && v.Op != ssa.OpStoreReg {
  7151  					s.SetPos(firstPos)
  7152  					firstPos = src.NoXPos
  7153  				}
  7154  				// Attach this safe point to the next
  7155  				// instruction.
  7156  				s.pp.NextLive = s.livenessMap.Get(v)
  7157  				s.pp.NextUnsafe = s.livenessMap.GetUnsafe(v)
  7158  
  7159  				// let the backend handle it
  7160  				Arch.SSAGenValue(&s, v)
  7161  			}
  7162  
  7163  			if idx, ok := argLiveValueMap[v.ID]; ok && idx != argLiveIdx {
  7164  				argLiveIdx = idx
  7165  				p := s.pp.Prog(obj.APCDATA)
  7166  				p.From.SetConst(rtabi.PCDATA_ArgLiveIndex)
  7167  				p.To.SetConst(int64(idx))
  7168  			}
  7169  
  7170  			if base.Ctxt.Flag_locationlists {
  7171  				valueToProgAfter[v.ID] = s.pp.Next
  7172  			}
  7173  
  7174  			if gatherPrintInfo {
  7175  				for ; x != s.pp.Next; x = x.Link {
  7176  					progToValue[x] = v
  7177  				}
  7178  			}
  7179  		}
  7180  		// If this is an empty infinite loop, stick a hardware NOP in there so that debuggers are less confused.
  7181  		if s.bstart[b.ID] == s.pp.Next && len(b.Succs) == 1 && b.Succs[0].Block() == b {
  7182  			p := Arch.Ginsnop(s.pp)
  7183  			p.Pos = p.Pos.WithIsStmt()
  7184  			if b.Pos == src.NoXPos {
  7185  				b.Pos = p.Pos // It needs a file, otherwise a no-file non-zero line causes confusion.  See #35652.
  7186  				if b.Pos == src.NoXPos {
  7187  					b.Pos = s.pp.Text.Pos // Sometimes p.Pos is empty.  See #35695.
  7188  				}
  7189  			}
  7190  			b.Pos = b.Pos.WithBogusLine() // Debuggers are not good about infinite loops, force a change in line number
  7191  		}
  7192  
  7193  		// Set unsafe mark for any end-of-block generated instructions
  7194  		// (normally, conditional or unconditional branches).
  7195  		// This is particularly important for empty blocks, as there
  7196  		// are no values to inherit the unsafe mark from.
  7197  		s.pp.NextUnsafe = s.livenessMap.GetUnsafeBlock(b)
  7198  
  7199  		// Emit control flow instructions for block
  7200  		var next *ssa.Block
  7201  		if i < len(f.Blocks)-1 && base.Flag.N == 0 {
  7202  			// If -N, leave next==nil so every block with successors
  7203  			// ends in a JMP (except call blocks - plive doesn't like
  7204  			// select{send,recv} followed by a JMP call).  Helps keep
  7205  			// line numbers for otherwise empty blocks.
  7206  			next = f.Blocks[i+1]
  7207  		}
  7208  		x := s.pp.Next
  7209  		s.SetPos(b.Pos)
  7210  		Arch.SSAGenBlock(&s, b, next)
  7211  		if gatherPrintInfo {
  7212  			for ; x != s.pp.Next; x = x.Link {
  7213  				progToBlock[x] = b
  7214  			}
  7215  		}
  7216  	}
  7217  	if f.Blocks[len(f.Blocks)-1].Kind == block.BlockExit {
  7218  		// We need the return address of a panic call to
  7219  		// still be inside the function in question. So if
  7220  		// it ends in a call which doesn't return, add a
  7221  		// nop (which will never execute) after the call.
  7222  		Arch.Ginsnop(s.pp)
  7223  	}
  7224  	if openDeferInfo != nil {
  7225  		// When doing open-coded defers, generate a disconnected call to
  7226  		// deferreturn and a return. This will be used to during panic
  7227  		// recovery to unwind the stack and return back to the runtime.
  7228  
  7229  		// Note that this exit code doesn't work if a return parameter
  7230  		// is heap-allocated, but open defers aren't enabled in that case.
  7231  
  7232  		// TODO either make this handle heap-allocated return parameters or reuse the other-defers general-purpose code path.
  7233  		s.pp.NextLive = s.livenessMap.DeferReturn
  7234  		p := s.pp.Prog(obj.ACALL)
  7235  		p.To.Type = obj.TYPE_MEM
  7236  		p.To.Name = obj.NAME_EXTERN
  7237  		p.To.Sym = ir.Syms.Deferreturn
  7238  
  7239  		// Load results into registers. So when a deferred function
  7240  		// recovers a panic, it will return to caller with right results.
  7241  		// The results are already in memory, because they are not SSA'd
  7242  		// when the function has defers (see canSSAName).
  7243  		for _, o := range f.OwnAux.ABIInfo().OutParams() {
  7244  			n := o.Name
  7245  			rts, offs := o.RegisterTypesAndOffsets()
  7246  			for i := range o.Registers {
  7247  				Arch.LoadRegResult(&s, f, rts[i], ssa.ObjRegForAbiReg(o.Registers[i], f.Config), n, offs[i])
  7248  			}
  7249  		}
  7250  
  7251  		s.pp.Prog(obj.ARET)
  7252  	}
  7253  
  7254  	if inlMarks != nil {
  7255  		hasCall := false
  7256  
  7257  		// We have some inline marks. Try to find other instructions we're
  7258  		// going to emit anyway, and use those instructions instead of the
  7259  		// inline marks.
  7260  		for p := s.pp.Text; p != nil; p = p.Link {
  7261  			if p.As == obj.ANOP || p.As == obj.AFUNCDATA || p.As == obj.APCDATA || p.As == obj.ATEXT ||
  7262  				p.As == obj.APCALIGN || p.As == obj.APCALIGNMAX || Arch.LinkArch.Family == sys.Wasm {
  7263  				// Don't use 0-sized instructions as inline marks, because we need
  7264  				// to identify inline mark instructions by pc offset.
  7265  				// (Some of these instructions are sometimes zero-sized, sometimes not.
  7266  				// We must not use anything that even might be zero-sized.)
  7267  				// TODO: are there others?
  7268  				continue
  7269  			}
  7270  			if _, ok := inlMarks[p]; ok {
  7271  				// Don't use inline marks themselves. We don't know
  7272  				// whether they will be zero-sized or not yet.
  7273  				continue
  7274  			}
  7275  			if p.As == obj.ACALL || p.As == obj.ADUFFCOPY || p.As == obj.ADUFFZERO {
  7276  				hasCall = true
  7277  			}
  7278  			pos := p.Pos.AtColumn1()
  7279  			marks := inlMarksByPos[pos]
  7280  			if len(marks) == 0 {
  7281  				continue
  7282  			}
  7283  			for _, m := range marks {
  7284  				// We found an instruction with the same source position as
  7285  				// some of the inline marks.
  7286  				// Use this instruction instead.
  7287  				p.Pos = p.Pos.WithIsStmt() // promote position to a statement
  7288  				s.pp.CurFunc.LSym.Func().AddInlMark(p, inlMarks[m])
  7289  				// Make the inline mark a real nop, so it doesn't generate any code.
  7290  				m.As = obj.ANOP
  7291  				m.Pos = src.NoXPos
  7292  				m.From = obj.Addr{}
  7293  				m.To = obj.Addr{}
  7294  			}
  7295  			delete(inlMarksByPos, pos)
  7296  		}
  7297  		// Any unmatched inline marks now need to be added to the inlining tree (and will generate a nop instruction).
  7298  		for _, p := range inlMarkList {
  7299  			if p.As != obj.ANOP {
  7300  				s.pp.CurFunc.LSym.Func().AddInlMark(p, inlMarks[p])
  7301  			}
  7302  		}
  7303  
  7304  		if e.stksize == 0 && !hasCall {
  7305  			// Frameless leaf function. It doesn't need any preamble,
  7306  			// so make sure its first instruction isn't from an inlined callee.
  7307  			// If it is, add a nop at the start of the function with a position
  7308  			// equal to the start of the function.
  7309  			// This ensures that runtime.FuncForPC(uintptr(reflect.ValueOf(fn).Pointer())).Name()
  7310  			// returns the right answer. See issue 58300.
  7311  			for p := s.pp.Text; p != nil; p = p.Link {
  7312  				if p.As == obj.AFUNCDATA || p.As == obj.APCDATA || p.As == obj.ATEXT || p.As == obj.ANOP {
  7313  					continue
  7314  				}
  7315  				if base.Ctxt.PosTable.Pos(p.Pos).Base().InliningIndex() >= 0 {
  7316  					// Make a real (not 0-sized) nop.
  7317  					nop := Arch.Ginsnop(s.pp)
  7318  					nop.Pos = e.curfn.Pos().WithIsStmt()
  7319  
  7320  					// Unfortunately, Ginsnop puts the instruction at the
  7321  					// end of the list. Move it up to just before p.
  7322  
  7323  					// Unlink from the current list.
  7324  					for x := s.pp.Text; x != nil; x = x.Link {
  7325  						if x.Link == nop {
  7326  							x.Link = nop.Link
  7327  							break
  7328  						}
  7329  					}
  7330  					// Splice in right before p.
  7331  					for x := s.pp.Text; x != nil; x = x.Link {
  7332  						if x.Link == p {
  7333  							nop.Link = p
  7334  							x.Link = nop
  7335  							break
  7336  						}
  7337  					}
  7338  				}
  7339  				break
  7340  			}
  7341  		}
  7342  	}
  7343  
  7344  	if base.Ctxt.Flag_locationlists {
  7345  		var debugInfo *ssa.FuncDebug
  7346  		debugInfo = e.curfn.DebugInfo.(*ssa.FuncDebug)
  7347  		// Save off entry ID in case we need it later for DWARF generation
  7348  		// for return values promoted to the heap.
  7349  		debugInfo.EntryID = f.Entry.ID
  7350  		if e.curfn.ABI == obj.ABIInternal && base.Flag.N != 0 {
  7351  			ssa.BuildFuncDebugNoOptimized(base.Ctxt, f, base.Debug.LocationLists > 1, StackOffset, debugInfo)
  7352  		} else {
  7353  			ssa.BuildFuncDebug(base.Ctxt, f, base.Debug.LocationLists, StackOffset, debugInfo)
  7354  		}
  7355  		bstart := s.bstart
  7356  		idToIdx := make([]int, f.NumBlocks())
  7357  		for i, b := range f.Blocks {
  7358  			idToIdx[b.ID] = i
  7359  		}
  7360  		// Register a callback that will be used later to fill in PCs into location
  7361  		// lists. At the moment, Prog.Pc is a sequence number; it's not a real PC
  7362  		// until after assembly, so the translation needs to be deferred.
  7363  		debugInfo.GetPC = func(b, v ssa.ID) int64 {
  7364  			switch v {
  7365  			case ssa.BlockStart.ID:
  7366  				if b == f.Entry.ID {
  7367  					return 0 // Start at the very beginning, at the assembler-generated prologue.
  7368  					// this should only happen for function args (ssa.OpArg)
  7369  				}
  7370  				return bstart[b].Pc
  7371  			case ssa.BlockEnd.ID:
  7372  				blk := f.Blocks[idToIdx[b]]
  7373  				nv := len(blk.Values)
  7374  				return valueToProgAfter[blk.Values[nv-1].ID].Pc
  7375  			case ssa.FuncEnd.ID:
  7376  				return e.curfn.LSym.Size
  7377  			default:
  7378  				return valueToProgAfter[v].Pc
  7379  			}
  7380  		}
  7381  	}
  7382  
  7383  	// Resolve branches, and relax DefaultStmt into NotStmt
  7384  	for _, br := range s.Branches {
  7385  		br.P.To.SetTarget(s.bstart[br.B.ID])
  7386  		if br.P.Pos.IsStmt() != src.PosIsStmt {
  7387  			br.P.Pos = br.P.Pos.WithNotStmt()
  7388  		} else if v0 := br.B.FirstPossibleStmtValue(); v0 != nil && v0.Pos.Line() == br.P.Pos.Line() && v0.Pos.IsStmt() == src.PosIsStmt {
  7389  			br.P.Pos = br.P.Pos.WithNotStmt()
  7390  		}
  7391  
  7392  	}
  7393  
  7394  	// Resolve jump table destinations.
  7395  	for _, jt := range s.JumpTables {
  7396  		// Convert from *Block targets to *Prog targets.
  7397  		targets := make([]*obj.Prog, len(jt.Succs))
  7398  		for i, e := range jt.Succs {
  7399  			targets[i] = s.bstart[e.Block().ID]
  7400  		}
  7401  		// Add to list of jump tables to be resolved at assembly time.
  7402  		// The assembler converts from *Prog entries to absolute addresses
  7403  		// once it knows instruction byte offsets.
  7404  		fi := s.pp.CurFunc.LSym.Func()
  7405  		fi.JumpTables = append(fi.JumpTables, obj.JumpTable{Sym: jt.Aux.(*obj.LSym), Targets: targets})
  7406  	}
  7407  
  7408  	// Finalize the frame, then let the backend run a final pass over the
  7409  	// generated Progs (e.g. arm64 fuses adjacent spill/reload MOVDs into
  7410  	// STP/LDP). Branch and jump-table targets are resolved at this point.
  7411  	// Doing this before the debug dumps below means -S and GOSSAFUNC's genssa
  7412  	// output reflect the instructions that are actually assembled. defframe
  7413  	// must run first: it finalizes the frame size, which the backend pass
  7414  	// depends on.
  7415  	defframe(&s, e, f)
  7416  	if Arch.SSAGenFinish != nil {
  7417  		Arch.SSAGenFinish(s.pp)
  7418  	}
  7419  
  7420  	if e.log { // spew to stdout
  7421  		filename := ""
  7422  		for p := s.pp.Text; p != nil; p = p.Link {
  7423  			if p.Pos.IsKnown() && p.InnermostFilename() != filename {
  7424  				filename = p.InnermostFilename()
  7425  				f.Logf("# %s\n", filename)
  7426  			}
  7427  
  7428  			var s string
  7429  			if v, ok := progToValue[p]; ok {
  7430  				s = v.String()
  7431  			} else if b, ok := progToBlock[p]; ok {
  7432  				s = b.String()
  7433  			} else {
  7434  				s = "   " // most value and branch strings are 2-3 characters long
  7435  			}
  7436  			f.Logf(" %-6s\t%.5d (%s)\t%s\n", s, p.Pc, p.InnermostLineNumber(), p.InstructionString())
  7437  		}
  7438  	}
  7439  	if htmlWriter != nil { // spew to ssa.html
  7440  		var buf strings.Builder
  7441  		buf.WriteString("<code>")
  7442  		buf.WriteString("<dl class=\"ssa-gen\">")
  7443  		filename := ""
  7444  
  7445  		liveness := lv.Format(nil)
  7446  		if liveness != "" {
  7447  			buf.WriteString("<dt class=\"ssa-prog-src\"></dt><dd class=\"ssa-prog\">")
  7448  			buf.WriteString(html.EscapeString("# " + liveness))
  7449  			buf.WriteString("</dd>")
  7450  		}
  7451  
  7452  		for p := s.pp.Text; p != nil; p = p.Link {
  7453  			// Don't spam every line with the file name, which is often huge.
  7454  			// Only print changes, and "unknown" is not a change.
  7455  			if p.Pos.IsKnown() && p.InnermostFilename() != filename {
  7456  				filename = p.InnermostFilename()
  7457  				buf.WriteString("<dt class=\"ssa-prog-src\"></dt><dd class=\"ssa-prog\">")
  7458  				buf.WriteString(html.EscapeString("# " + filename))
  7459  				buf.WriteString("</dd>")
  7460  			}
  7461  
  7462  			buf.WriteString("<dt class=\"ssa-prog-src\">")
  7463  			if v, ok := progToValue[p]; ok {
  7464  
  7465  				// Prefix calls with their liveness, if any
  7466  				if p.As != obj.APCDATA {
  7467  					if liveness := lv.Format(v); liveness != "" {
  7468  						// Steal this line, and restart a line
  7469  						buf.WriteString("</dt><dd class=\"ssa-prog\">")
  7470  						buf.WriteString(html.EscapeString("# " + liveness))
  7471  						buf.WriteString("</dd>")
  7472  						// restarting a line
  7473  						buf.WriteString("<dt class=\"ssa-prog-src\">")
  7474  					}
  7475  				}
  7476  
  7477  				buf.WriteString(v.HTML())
  7478  			} else if b, ok := progToBlock[p]; ok {
  7479  				buf.WriteString("<b>" + b.HTML() + "</b>")
  7480  			}
  7481  			buf.WriteString("</dt>")
  7482  			buf.WriteString("<dd class=\"ssa-prog\">")
  7483  			fmt.Fprintf(&buf, "%.5d <span class=\"l%v line-number\">(%s)</span> %s", p.Pc, p.InnermostLineNumber(), p.InnermostLineNumberHTML(), html.EscapeString(p.InstructionString()))
  7484  			buf.WriteString("</dd>")
  7485  		}
  7486  		buf.WriteString("</dl>")
  7487  		buf.WriteString("</code>")
  7488  		htmlWriter.WriteColumn("genssa", "genssa", "ssa-prog", buf.String())
  7489  	}
  7490  	if ssaconfig.GenssaDump[f.Name] {
  7491  		fi := f.DumpFileForPhase("genssa")
  7492  		if fi != nil {
  7493  
  7494  			// inliningDiffers if any filename changes or if any line number except the innermost (last index) changes.
  7495  			inliningDiffers := func(a, b []src.Pos) bool {
  7496  				if len(a) != len(b) {
  7497  					return true
  7498  				}
  7499  				for i := range a {
  7500  					if a[i].Filename() != b[i].Filename() {
  7501  						return true
  7502  					}
  7503  					if i != len(a)-1 && a[i].Line() != b[i].Line() {
  7504  						return true
  7505  					}
  7506  				}
  7507  				return false
  7508  			}
  7509  
  7510  			var allPosOld []src.Pos
  7511  			var allPos []src.Pos
  7512  
  7513  			for p := s.pp.Text; p != nil; p = p.Link {
  7514  				if p.Pos.IsKnown() {
  7515  					allPos = allPos[:0]
  7516  					p.Ctxt.AllPos(p.Pos, func(pos src.Pos) { allPos = append(allPos, pos) })
  7517  					if inliningDiffers(allPos, allPosOld) {
  7518  						for _, pos := range allPos {
  7519  							fmt.Fprintf(fi, "# %s:%d\n", pos.Filename(), pos.Line())
  7520  						}
  7521  						allPos, allPosOld = allPosOld, allPos // swap, not copy, so that they do not share slice storage.
  7522  					}
  7523  				}
  7524  
  7525  				var s string
  7526  				if v, ok := progToValue[p]; ok {
  7527  					s = v.String()
  7528  				} else if b, ok := progToBlock[p]; ok {
  7529  					s = b.String()
  7530  				} else {
  7531  					s = "   " // most value and branch strings are 2-3 characters long
  7532  				}
  7533  				fmt.Fprintf(fi, " %-6s\t%.5d %s\t%s\n", s, p.Pc, ssa.StmtString(p.Pos), p.InstructionString())
  7534  			}
  7535  			fi.Close()
  7536  		}
  7537  	}
  7538  
  7539  	htmlWriter.Close()
  7540  	htmlWriter = nil
  7541  }
  7542  
  7543  func defframe(s *State, e *ssafn, f *ssa.Func) {
  7544  	pp := s.pp
  7545  
  7546  	s.maxarg = types.RoundUp(s.maxarg, e.stkalign)
  7547  	frame := s.maxarg + e.stksize
  7548  	if Arch.PadFrame != nil {
  7549  		frame = Arch.PadFrame(frame)
  7550  	}
  7551  
  7552  	// Fill in argument and frame size.
  7553  	pp.Text.To.Type = obj.TYPE_TEXTSIZE
  7554  	pp.Text.To.Val = int32(types.RoundUp(f.OwnAux.ArgWidth(), int64(types.RegSize)))
  7555  	pp.Text.To.Offset = frame
  7556  
  7557  	p := pp.Text
  7558  
  7559  	// Insert code to spill argument registers if the named slot may be partially
  7560  	// live. That is, the named slot is considered live by liveness analysis,
  7561  	// (because a part of it is live), but we may not spill all parts into the
  7562  	// slot. This can only happen with aggregate-typed arguments that are SSA-able
  7563  	// and not address-taken (for non-SSA-able or address-taken arguments we always
  7564  	// spill upfront).
  7565  	// Note: spilling is unnecessary in the -N/no-optimize case, since all values
  7566  	// will be considered non-SSAable and spilled up front.
  7567  	// TODO(register args) Make liveness more fine-grained to that partial spilling is okay.
  7568  	if f.OwnAux.ABIInfo().InRegistersUsed() != 0 && base.Flag.N == 0 {
  7569  		// First, see if it is already spilled before it may be live. Look for a spill
  7570  		// in the entry block up to the first safepoint.
  7571  		type nameOff struct {
  7572  			n   *ir.Name
  7573  			off int64
  7574  		}
  7575  		partLiveArgsSpilled := make(map[nameOff]bool)
  7576  		for _, v := range f.Entry.Values {
  7577  			if v.Op.IsCall() {
  7578  				break
  7579  			}
  7580  			if v.Op != ssa.OpStoreReg || v.Args[0].Op != ssa.OpArgIntReg {
  7581  				continue
  7582  			}
  7583  			n, off := ssa.AutoVar(v)
  7584  			if n.Class != ir.PPARAM || n.Addrtaken() || !ssa.CanSSA(n.Type()) || !s.partLiveArgs[n] {
  7585  				continue
  7586  			}
  7587  			partLiveArgsSpilled[nameOff{n, off}] = true
  7588  		}
  7589  
  7590  		// Then, insert code to spill registers if not already.
  7591  		for _, a := range f.OwnAux.ABIInfo().InParams() {
  7592  			n := a.Name
  7593  			if n == nil || n.Addrtaken() || !ssa.CanSSA(n.Type()) || !s.partLiveArgs[n] || len(a.Registers) <= 1 {
  7594  				continue
  7595  			}
  7596  			rts, offs := a.RegisterTypesAndOffsets()
  7597  			for i := range a.Registers {
  7598  				if !rts[i].HasPointers() {
  7599  					continue
  7600  				}
  7601  				if partLiveArgsSpilled[nameOff{n, offs[i]}] {
  7602  					continue // already spilled
  7603  				}
  7604  				reg := ssa.ObjRegForAbiReg(a.Registers[i], f.Config)
  7605  				p = Arch.SpillArgReg(pp, p, f, rts[i], reg, n, offs[i])
  7606  			}
  7607  		}
  7608  	}
  7609  
  7610  	// Insert code to zero ambiguously live variables so that the
  7611  	// garbage collector only sees initialized values when it
  7612  	// looks for pointers.
  7613  	var lo, hi int64
  7614  
  7615  	// Opaque state for backend to use. Current backends use it to
  7616  	// keep track of which helper registers have been zeroed.
  7617  	var state uint32
  7618  
  7619  	// Iterate through declarations. Autos are sorted in decreasing
  7620  	// frame offset order.
  7621  	for _, n := range e.curfn.Dcl {
  7622  		if !n.Needzero() {
  7623  			continue
  7624  		}
  7625  		if n.Class != ir.PAUTO {
  7626  			e.Fatalf(n.Pos(), "needzero class %d", n.Class)
  7627  		}
  7628  		if n.Type().Size()%int64(types.PtrSize) != 0 || n.FrameOffset()%int64(types.PtrSize) != 0 || n.Type().Size() == 0 {
  7629  			e.Fatalf(n.Pos(), "var %L has size %d offset %d", n, n.Type().Size(), n.Offset_)
  7630  		}
  7631  
  7632  		if lo != hi && n.FrameOffset()+n.Type().Size() >= lo-int64(2*types.RegSize) {
  7633  			// Merge with range we already have.
  7634  			lo = n.FrameOffset()
  7635  			continue
  7636  		}
  7637  
  7638  		// Zero old range
  7639  		p = Arch.ZeroRange(pp, p, frame+lo, hi-lo, &state)
  7640  
  7641  		// Set new range.
  7642  		lo = n.FrameOffset()
  7643  		hi = lo + n.Type().Size()
  7644  	}
  7645  
  7646  	// Zero final range.
  7647  	Arch.ZeroRange(pp, p, frame+lo, hi-lo, &state)
  7648  }
  7649  
  7650  // For generating consecutive jump instructions to model a specific branching
  7651  type IndexJump struct {
  7652  	Jump  obj.As
  7653  	Index int
  7654  }
  7655  
  7656  func (s *State) oneJump(b *ssa.Block, jump *IndexJump) {
  7657  	p := s.Br(jump.Jump, b.Succs[jump.Index].Block())
  7658  	p.Pos = b.Pos
  7659  }
  7660  
  7661  // CombJump generates combinational instructions (2 at present) for a block jump,
  7662  // thereby the behaviour of non-standard condition codes could be simulated
  7663  func (s *State) CombJump(b, next *ssa.Block, jumps *[2][2]IndexJump) {
  7664  	switch next {
  7665  	case b.Succs[0].Block():
  7666  		s.oneJump(b, &jumps[0][0])
  7667  		s.oneJump(b, &jumps[0][1])
  7668  	case b.Succs[1].Block():
  7669  		s.oneJump(b, &jumps[1][0])
  7670  		s.oneJump(b, &jumps[1][1])
  7671  	default:
  7672  		var q *obj.Prog
  7673  		if b.Likely != ssa.BranchUnlikely {
  7674  			s.oneJump(b, &jumps[1][0])
  7675  			s.oneJump(b, &jumps[1][1])
  7676  			q = s.Br(obj.AJMP, b.Succs[1].Block())
  7677  		} else {
  7678  			s.oneJump(b, &jumps[0][0])
  7679  			s.oneJump(b, &jumps[0][1])
  7680  			q = s.Br(obj.AJMP, b.Succs[0].Block())
  7681  		}
  7682  		q.Pos = b.Pos
  7683  	}
  7684  }
  7685  
  7686  // AddAux adds the offset in the aux fields (AuxInt and Aux) of v to a.
  7687  func AddAux(a *obj.Addr, v *ssa.Value) {
  7688  	AddAux2(a, v, v.AuxInt)
  7689  }
  7690  func AddAux2(a *obj.Addr, v *ssa.Value, offset int64) {
  7691  	if a.Type != obj.TYPE_MEM && a.Type != obj.TYPE_ADDR {
  7692  		v.Fatalf("bad AddAux addr %v", a)
  7693  	}
  7694  	// add integer offset
  7695  	a.Offset += offset
  7696  
  7697  	// If no additional symbol offset, we're done.
  7698  	if v.Aux == nil {
  7699  		return
  7700  	}
  7701  	// Add symbol's offset from its base register.
  7702  	switch n := v.Aux.(type) {
  7703  	case *ssa.AuxCall:
  7704  		a.Name = obj.NAME_EXTERN
  7705  		a.Sym = n.Fn
  7706  	case *obj.LSym:
  7707  		a.Name = obj.NAME_EXTERN
  7708  		a.Sym = n
  7709  	case *ir.Name:
  7710  		if n.Class == ir.PPARAM || (n.Class == ir.PPARAMOUT && !n.IsOutputParamInRegisters()) {
  7711  			a.Name = obj.NAME_PARAM
  7712  		} else {
  7713  			a.Name = obj.NAME_AUTO
  7714  		}
  7715  		a.Sym = n.Linksym()
  7716  		a.Offset += n.FrameOffset()
  7717  	default:
  7718  		v.Fatalf("aux in %s not implemented %#v", v, v.Aux)
  7719  	}
  7720  }
  7721  
  7722  // extendIndex extends v to a full int width.
  7723  // panic with the given kind if v does not fit in an int (only on 32-bit archs).
  7724  func (s *state) extendIndex(idx, len *ssa.Value, kind ssa.BoundsKind, bounded bool) *ssa.Value {
  7725  	size := idx.Type.Size()
  7726  	if size == s.config.PtrSize {
  7727  		return idx
  7728  	}
  7729  	if size > s.config.PtrSize {
  7730  		// truncate 64-bit indexes on 32-bit pointer archs. Test the
  7731  		// high word and branch to out-of-bounds failure if it is not 0.
  7732  		var lo *ssa.Value
  7733  		if idx.Type.IsSigned() {
  7734  			lo = s.newValue1(ssa.OpInt64Lo, types.Types[types.TINT], idx)
  7735  		} else {
  7736  			lo = s.newValue1(ssa.OpInt64Lo, types.Types[types.TUINT], idx)
  7737  		}
  7738  		if bounded || base.Flag.B != 0 {
  7739  			return lo
  7740  		}
  7741  		bNext := s.f.NewBlock(block.BlockPlain)
  7742  		bPanic := s.f.NewBlock(block.BlockExit)
  7743  		hi := s.newValue1(ssa.OpInt64Hi, types.Types[types.TUINT32], idx)
  7744  		cmp := s.newValue2(ssa.OpEq32, types.Types[types.TBOOL], hi, s.constInt32(types.Types[types.TUINT32], 0))
  7745  		if !idx.Type.IsSigned() {
  7746  			switch kind {
  7747  			case ssa.BoundsIndex:
  7748  				kind = ssa.BoundsIndexU
  7749  			case ssa.BoundsSliceAlen:
  7750  				kind = ssa.BoundsSliceAlenU
  7751  			case ssa.BoundsSliceAcap:
  7752  				kind = ssa.BoundsSliceAcapU
  7753  			case ssa.BoundsSliceB:
  7754  				kind = ssa.BoundsSliceBU
  7755  			case ssa.BoundsSlice3Alen:
  7756  				kind = ssa.BoundsSlice3AlenU
  7757  			case ssa.BoundsSlice3Acap:
  7758  				kind = ssa.BoundsSlice3AcapU
  7759  			case ssa.BoundsSlice3B:
  7760  				kind = ssa.BoundsSlice3BU
  7761  			case ssa.BoundsSlice3C:
  7762  				kind = ssa.BoundsSlice3CU
  7763  			}
  7764  		}
  7765  		b := s.endBlock()
  7766  		b.Kind = block.BlockIf
  7767  		b.SetControl(cmp)
  7768  		b.Likely = ssa.BranchLikely
  7769  		b.AddEdgeTo(bNext)
  7770  		b.AddEdgeTo(bPanic)
  7771  
  7772  		s.startBlock(bPanic)
  7773  		mem := s.newValue4I(ssa.OpPanicExtend, types.TypeMem, int64(kind), hi, lo, len, s.mem())
  7774  		s.endBlock().SetControl(mem)
  7775  		s.startBlock(bNext)
  7776  
  7777  		return lo
  7778  	}
  7779  
  7780  	// Extend value to the required size
  7781  	var op ssa.Op
  7782  	if idx.Type.IsSigned() {
  7783  		switch 10*size + s.config.PtrSize {
  7784  		case 14:
  7785  			op = ssa.OpSignExt8to32
  7786  		case 18:
  7787  			op = ssa.OpSignExt8to64
  7788  		case 24:
  7789  			op = ssa.OpSignExt16to32
  7790  		case 28:
  7791  			op = ssa.OpSignExt16to64
  7792  		case 48:
  7793  			op = ssa.OpSignExt32to64
  7794  		default:
  7795  			s.Fatalf("bad signed index extension %s", idx.Type)
  7796  		}
  7797  	} else {
  7798  		switch 10*size + s.config.PtrSize {
  7799  		case 14:
  7800  			op = ssa.OpZeroExt8to32
  7801  		case 18:
  7802  			op = ssa.OpZeroExt8to64
  7803  		case 24:
  7804  			op = ssa.OpZeroExt16to32
  7805  		case 28:
  7806  			op = ssa.OpZeroExt16to64
  7807  		case 48:
  7808  			op = ssa.OpZeroExt32to64
  7809  		default:
  7810  			s.Fatalf("bad unsigned index extension %s", idx.Type)
  7811  		}
  7812  	}
  7813  	return s.newValue1(op, types.Types[types.TINT], idx)
  7814  }
  7815  
  7816  // CheckLoweredPhi checks that regalloc and stackalloc correctly handled phi values.
  7817  // Called during ssaGenValue.
  7818  func CheckLoweredPhi(v *ssa.Value) {
  7819  	if v.Op != ssa.OpPhi {
  7820  		v.Fatalf("CheckLoweredPhi called with non-phi value: %v", v.LongString())
  7821  	}
  7822  	if v.Type.IsMemory() {
  7823  		return
  7824  	}
  7825  	f := v.Block.Func
  7826  	loc := f.RegAlloc[v.ID]
  7827  	for _, a := range v.Args {
  7828  		if aloc := f.RegAlloc[a.ID]; aloc != loc { // TODO: .Equal() instead?
  7829  			v.Fatalf("phi arg at different location than phi: %v @ %s, but arg %v @ %s\n%s\n", v, loc, a, aloc, v.Block.Func)
  7830  		}
  7831  	}
  7832  }
  7833  
  7834  // CheckLoweredGetClosurePtr checks that v is the first instruction in the function's entry block,
  7835  // except for incoming in-register arguments.
  7836  // The output of LoweredGetClosurePtr is generally hardwired to the correct register.
  7837  // That register contains the closure pointer on closure entry.
  7838  func CheckLoweredGetClosurePtr(v *ssa.Value) {
  7839  	entry := v.Block.Func.Entry
  7840  	if entry != v.Block {
  7841  		base.Fatalf("in %s, badly placed LoweredGetClosurePtr: %v %v", v.Block.Func.Name, v.Block, v)
  7842  	}
  7843  	for _, w := range entry.Values {
  7844  		if w == v {
  7845  			break
  7846  		}
  7847  		switch w.Op {
  7848  		case ssa.OpArgIntReg, ssa.OpArgFloatReg:
  7849  			// okay
  7850  		default:
  7851  			base.Fatalf("in %s, badly placed LoweredGetClosurePtr: %v %v", v.Block.Func.Name, v.Block, v)
  7852  		}
  7853  	}
  7854  }
  7855  
  7856  // CheckArgReg ensures that v is in the function's entry block.
  7857  func CheckArgReg(v *ssa.Value) {
  7858  	entry := v.Block.Func.Entry
  7859  	if entry != v.Block {
  7860  		base.Fatalf("in %s, badly placed ArgIReg or ArgFReg: %v %v", v.Block.Func.Name, v.Block, v)
  7861  	}
  7862  }
  7863  
  7864  func AddrAuto(a *obj.Addr, v *ssa.Value) {
  7865  	n, off := ssa.AutoVar(v)
  7866  	a.Type = obj.TYPE_MEM
  7867  	a.Sym = n.Linksym()
  7868  	a.Reg = int16(Arch.REGSP)
  7869  	a.Offset = n.FrameOffset() + off
  7870  	if n.Class == ir.PPARAM || (n.Class == ir.PPARAMOUT && !n.IsOutputParamInRegisters()) {
  7871  		a.Name = obj.NAME_PARAM
  7872  	} else {
  7873  		a.Name = obj.NAME_AUTO
  7874  	}
  7875  }
  7876  
  7877  // Call returns a new CALL instruction for the SSA value v.
  7878  // It uses PrepareCall to prepare the call.
  7879  func (s *State) Call(v *ssa.Value) *obj.Prog {
  7880  	pPosIsStmt := s.pp.Pos.IsStmt() // The statement-ness of the call comes from ssaGenState
  7881  	s.PrepareCall(v)
  7882  
  7883  	p := s.Prog(obj.ACALL)
  7884  	if pPosIsStmt == src.PosIsStmt {
  7885  		p.Pos = v.Pos.WithIsStmt()
  7886  	} else {
  7887  		p.Pos = v.Pos.WithNotStmt()
  7888  	}
  7889  	if sym, ok := v.Aux.(*ssa.AuxCall); ok && sym.Fn != nil {
  7890  		p.To.Type = obj.TYPE_MEM
  7891  		p.To.Name = obj.NAME_EXTERN
  7892  		p.To.Sym = sym.Fn
  7893  	} else {
  7894  		// TODO(mdempsky): Can these differences be eliminated?
  7895  		switch Arch.LinkArch.Family {
  7896  		case sys.AMD64, sys.I386, sys.PPC64, sys.RISCV64, sys.S390X, sys.Wasm:
  7897  			p.To.Type = obj.TYPE_REG
  7898  		case sys.ARM, sys.ARM64, sys.Loong64, sys.MIPS, sys.MIPS64:
  7899  			p.To.Type = obj.TYPE_MEM
  7900  		default:
  7901  			base.Fatalf("unknown indirect call family")
  7902  		}
  7903  		p.To.Reg = v.Args[0].Reg()
  7904  	}
  7905  	return p
  7906  }
  7907  
  7908  // TailCall returns a new tail call instruction for the SSA value v.
  7909  // It is like Call, but for a tail call.
  7910  func (s *State) TailCall(v *ssa.Value) *obj.Prog {
  7911  	p := s.Call(v)
  7912  	p.As = obj.ARET
  7913  	return p
  7914  }
  7915  
  7916  // PrepareCall prepares to emit a CALL instruction for v and does call-related bookkeeping.
  7917  // It must be called immediately before emitting the actual CALL instruction,
  7918  // since it emits PCDATA for the stack map at the call (calls are safe points).
  7919  func (s *State) PrepareCall(v *ssa.Value) {
  7920  	idx := s.livenessMap.Get(v)
  7921  	if !idx.StackMapValid() {
  7922  		// See Liveness.hasStackMap.
  7923  		if sym, ok := v.Aux.(*ssa.AuxCall); !ok || !(sym.Fn == ir.Syms.WBZero || sym.Fn == ir.Syms.WBMove) {
  7924  			base.Fatalf("missing stack map index for %v", v.LongString())
  7925  		}
  7926  	}
  7927  
  7928  	call, ok := v.Aux.(*ssa.AuxCall)
  7929  
  7930  	if ok {
  7931  		// Record call graph information for nowritebarrierrec
  7932  		// analysis.
  7933  		if nowritebarrierrecCheck != nil {
  7934  			nowritebarrierrecCheck.recordCall(s.pp.CurFunc, call.Fn, v.Pos)
  7935  		}
  7936  	}
  7937  
  7938  	if s.maxarg < v.AuxInt {
  7939  		s.maxarg = v.AuxInt
  7940  	}
  7941  }
  7942  
  7943  // UseArgs records the fact that an instruction needs a certain amount of
  7944  // callee args space for its use.
  7945  func (s *State) UseArgs(n int64) {
  7946  	if s.maxarg < n {
  7947  		s.maxarg = n
  7948  	}
  7949  }
  7950  
  7951  // fieldIdx finds the index of the field referred to by the ODOT node n.
  7952  func fieldIdx(n *ir.SelectorExpr) int {
  7953  	t := n.X.Type()
  7954  	if !isStructNotSIMD(t) {
  7955  		panic("ODOT's LHS is not a struct")
  7956  	}
  7957  
  7958  	for i, f := range t.Fields() {
  7959  		if f.Sym == n.Sel {
  7960  			if f.Offset != n.Offset() {
  7961  				panic("field offset doesn't match")
  7962  			}
  7963  			return i
  7964  		}
  7965  	}
  7966  	panic(fmt.Sprintf("can't find field in expr %v\n", n))
  7967  
  7968  	// TODO: keep the result of this function somewhere in the ODOT Node
  7969  	// so we don't have to recompute it each time we need it.
  7970  }
  7971  
  7972  // ssafn holds frontend information about a function that the backend is processing.
  7973  // It also exports a bunch of compiler services for the ssa backend.
  7974  type ssafn struct {
  7975  	curfn      *ir.Func
  7976  	strings    map[string]*obj.LSym // map from constant string to data symbols
  7977  	stksize    int64                // stack size for current frame
  7978  	stkptrsize int64                // prefix of stack containing pointers
  7979  
  7980  	// alignment for current frame.
  7981  	// NOTE: when stkalign > PtrSize, currently this only ensures the offsets of
  7982  	// objects in the stack frame are aligned. The stack pointer is still aligned
  7983  	// only PtrSize.
  7984  	stkalign int64
  7985  
  7986  	log bool // print ssa debug to the stdout
  7987  }
  7988  
  7989  // StringData returns a symbol which
  7990  // is the data component of a global string constant containing s.
  7991  func (e *ssafn) StringData(s string) *obj.LSym {
  7992  	if aux, ok := e.strings[s]; ok {
  7993  		return aux
  7994  	}
  7995  	if e.strings == nil {
  7996  		e.strings = make(map[string]*obj.LSym)
  7997  	}
  7998  	data := staticdata.StringSym(e.curfn.Pos(), s)
  7999  	e.strings[s] = data
  8000  	return data
  8001  }
  8002  
  8003  // SplitSlot returns a slot representing the data of parent starting at offset.
  8004  func (e *ssafn) SplitSlot(parent *ssa.LocalSlot, suffix string, offset int64, t *types.Type) ssa.LocalSlot {
  8005  	node := parent.N
  8006  
  8007  	if node.Class != ir.PAUTO || node.Addrtaken() {
  8008  		// addressed things and non-autos retain their parents (i.e., cannot truly be split)
  8009  		return ssa.LocalSlot{N: node, Type: t, Off: parent.Off + offset}
  8010  	}
  8011  
  8012  	sym := &types.Sym{Name: node.Sym().Name + suffix, Pkg: types.LocalPkg}
  8013  	n := e.curfn.NewLocal(parent.N.Pos(), sym, t)
  8014  	n.SetUsed(true)
  8015  	n.SetEsc(ir.EscNever)
  8016  	types.CalcSize(t)
  8017  	return ssa.LocalSlot{N: n, Type: t, Off: 0, SplitOf: parent, SplitOffset: offset}
  8018  }
  8019  
  8020  // Logf logs a message from the compiler.
  8021  func (e *ssafn) Logf(msg string, args ...any) {
  8022  	if e.log {
  8023  		fmt.Printf(msg, args...)
  8024  	}
  8025  }
  8026  
  8027  func (e *ssafn) Log() bool {
  8028  	return e.log
  8029  }
  8030  
  8031  // Fatalf reports a compiler error and exits.
  8032  func (e *ssafn) Fatalf(pos src.XPos, msg string, args ...any) {
  8033  	base.Pos = pos
  8034  	nargs := append([]any{ir.FuncName(e.curfn)}, args...)
  8035  	base.Fatalf("'%s': "+msg, nargs...)
  8036  }
  8037  
  8038  // Warnl reports a "warning", which is usually flag-triggered
  8039  // logging output for the benefit of tests.
  8040  func (e *ssafn) Warnl(pos src.XPos, fmt_ string, args ...any) {
  8041  	base.WarnfAt(pos, fmt_, args...)
  8042  }
  8043  
  8044  func (e *ssafn) Debug_checknil() bool {
  8045  	return base.Debug.Nil != 0
  8046  }
  8047  
  8048  func (e *ssafn) UseWriteBarrier() bool {
  8049  	return base.Flag.WB
  8050  }
  8051  
  8052  func (e *ssafn) Syslook(name string) *obj.LSym {
  8053  	switch name {
  8054  	case "goschedguarded":
  8055  		return ir.Syms.Goschedguarded
  8056  	case "writeBarrier":
  8057  		return ir.Syms.WriteBarrier
  8058  	case "wbZero":
  8059  		return ir.Syms.WBZero
  8060  	case "wbMove":
  8061  		return ir.Syms.WBMove
  8062  	case "cgoCheckMemmove":
  8063  		return ir.Syms.CgoCheckMemmove
  8064  	case "cgoCheckPtrWrite":
  8065  		return ir.Syms.CgoCheckPtrWrite
  8066  	}
  8067  	e.Fatalf(src.NoXPos, "unknown Syslook func %v", name)
  8068  	return nil
  8069  }
  8070  
  8071  func (e *ssafn) Func() *ir.Func {
  8072  	return e.curfn
  8073  }
  8074  
  8075  func clobberBase(n ir.Node) ir.Node {
  8076  	if n.Op() == ir.ODOT {
  8077  		n := n.(*ir.SelectorExpr)
  8078  		if n.X.Type().NumFields() == 1 {
  8079  			return clobberBase(n.X)
  8080  		}
  8081  	}
  8082  	if n.Op() == ir.OINDEX {
  8083  		n := n.(*ir.IndexExpr)
  8084  		if n.X.Type().IsArray() && n.X.Type().NumElem() == 1 {
  8085  			return clobberBase(n.X)
  8086  		}
  8087  	}
  8088  	return n
  8089  }
  8090  
  8091  // callTargetLSym returns the correct LSym to call 'callee' using its ABI.
  8092  func callTargetLSym(callee *ir.Name) *obj.LSym {
  8093  	if callee.Func == nil {
  8094  		// TODO(austin): This happens in case of interface method I.M from imported package.
  8095  		// It's ABIInternal, and would be better if callee.Func was never nil and we didn't
  8096  		// need this case.
  8097  		return callee.Linksym()
  8098  	}
  8099  
  8100  	return callee.LinksymABI(callee.Func.ABI)
  8101  }
  8102  
  8103  // deferStructFnField is the field index of _defer.fn.
  8104  const deferStructFnField = 4
  8105  
  8106  var deferType *types.Type
  8107  
  8108  // deferstruct returns a type interchangeable with runtime._defer.
  8109  // Make sure this stays in sync with runtime/runtime2.go:_defer.
  8110  func deferstruct() *types.Type {
  8111  	if deferType != nil {
  8112  		return deferType
  8113  	}
  8114  
  8115  	makefield := func(name string, t *types.Type) *types.Field {
  8116  		sym := (*types.Pkg)(nil).Lookup(name)
  8117  		return types.NewField(src.NoXPos, sym, t)
  8118  	}
  8119  
  8120  	fields := []*types.Field{
  8121  		makefield("heap", types.Types[types.TBOOL]),
  8122  		makefield("rangefunc", types.Types[types.TBOOL]),
  8123  		makefield("sp", types.Types[types.TUINTPTR]),
  8124  		makefield("pc", types.Types[types.TUINTPTR]),
  8125  		// Note: the types here don't really matter. Defer structures
  8126  		// are always scanned explicitly during stack copying and GC,
  8127  		// so we make them uintptr type even though they are real pointers.
  8128  		makefield("fn", types.Types[types.TUINTPTR]),
  8129  		makefield("link", types.Types[types.TUINTPTR]),
  8130  		makefield("head", types.Types[types.TUINTPTR]),
  8131  	}
  8132  	if name := fields[deferStructFnField].Sym.Name; name != "fn" {
  8133  		base.Fatalf("deferStructFnField is %q, not fn", name)
  8134  	}
  8135  
  8136  	n := ir.NewDeclNameAt(src.NoXPos, ir.OTYPE, ir.Pkgs.Runtime.Lookup("_defer"))
  8137  	typ := types.NewNamed(n)
  8138  	n.SetType(typ)
  8139  	n.SetTypecheck(1)
  8140  
  8141  	// build struct holding the above fields
  8142  	typ.SetUnderlying(types.NewStruct(fields))
  8143  	types.CalcStructSize(typ)
  8144  
  8145  	deferType = typ
  8146  	return typ
  8147  }
  8148  
  8149  // SpillSlotAddr uses LocalSlot information to initialize an obj.Addr
  8150  // The resulting addr is used in a non-standard context -- in the prologue
  8151  // of a function, before the frame has been constructed, so the standard
  8152  // addressing for the parameters will be wrong.
  8153  func SpillSlotAddr(spill ssa.Spill, baseReg int16, extraOffset int64) obj.Addr {
  8154  	return obj.Addr{
  8155  		Name:   obj.NAME_NONE,
  8156  		Type:   obj.TYPE_MEM,
  8157  		Reg:    baseReg,
  8158  		Offset: spill.Offset + extraOffset,
  8159  	}
  8160  }
  8161  
  8162  func isStructNotSIMD(t *types.Type) bool {
  8163  	return t.IsStruct() && !t.IsSIMD()
  8164  }
  8165  
  8166  var BoundsCheckFunc [ssa.BoundsKindCount]*obj.LSym
  8167