Adding upstream version 1.22.1.upstream/1.22.1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 620 insertions, 0 deletions

diff --git a/src/cmd/compile/internal/ssa/value.go b/src/cmd/compile/internal/ssa/value.go
new file mode 100644
index 0000000..4eaab40
--- /dev/null
+++ b/src/cmd/compile/internal/ssa/value.go
@@ -0,0 +1,620 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package ssa
+
+import (
+	"cmd/compile/internal/ir"
+	"cmd/compile/internal/types"
+	"cmd/internal/src"
+	"fmt"
+	"math"
+	"sort"
+	"strings"
+)
+
+// A Value represents a value in the SSA representation of the program.
+// The ID and Type fields must not be modified. The remainder may be modified
+// if they preserve the value of the Value (e.g. changing a (mul 2 x) to an (add x x)).
+type Value struct {
+	// A unique identifier for the value. For performance we allocate these IDs
+	// densely starting at 1.  There is no guarantee that there won't be occasional holes, though.
+	ID ID
+
+	// The operation that computes this value. See op.go.
+	Op Op
+
+	// The type of this value. Normally this will be a Go type, but there
+	// are a few other pseudo-types, see ../types/type.go.
+	Type *types.Type
+
+	// Auxiliary info for this value. The type of this information depends on the opcode and type.
+	// AuxInt is used for integer values, Aux is used for other values.
+	// Floats are stored in AuxInt using math.Float64bits(f).
+	// Unused portions of AuxInt are filled by sign-extending the used portion,
+	// even if the represented value is unsigned.
+	// Users of AuxInt which interpret AuxInt as unsigned (e.g. shifts) must be careful.
+	// Use Value.AuxUnsigned to get the zero-extended value of AuxInt.
+	AuxInt int64
+	Aux    Aux
+
+	// Arguments of this value
+	Args []*Value
+
+	// Containing basic block
+	Block *Block
+
+	// Source position
+	Pos src.XPos
+
+	// Use count. Each appearance in Value.Args and Block.Controls counts once.
+	Uses int32
+
+	// wasm: Value stays on the WebAssembly stack. This value will not get a "register" (WebAssembly variable)
+	// nor a slot on Go stack, and the generation of this value is delayed to its use time.
+	OnWasmStack bool
+
+	// Is this value in the per-function constant cache? If so, remove from cache before changing it or recycling it.
+	InCache bool
+
+	// Storage for the first three args
+	argstorage [3]*Value
+}
+
+// Examples:
+// Opcode          aux   args
+//  OpAdd          nil      2
+//  OpConst     string      0    string constant
+//  OpConst      int64      0    int64 constant
+//  OpAddcq      int64      1    amd64 op: v = arg[0] + constant
+
+// short form print. Just v#.
+func (v *Value) String() string {
+	if v == nil {
+		return "nil" // should never happen, but not panicking helps with debugging
+	}
+	return fmt.Sprintf("v%d", v.ID)
+}
+
+func (v *Value) AuxInt8() int8 {
+	if opcodeTable[v.Op].auxType != auxInt8 && opcodeTable[v.Op].auxType != auxNameOffsetInt8 {
+		v.Fatalf("op %s doesn't have an int8 aux field", v.Op)
+	}
+	return int8(v.AuxInt)
+}
+
+func (v *Value) AuxUInt8() uint8 {
+	if opcodeTable[v.Op].auxType != auxUInt8 {
+		v.Fatalf("op %s doesn't have a uint8 aux field", v.Op)
+	}
+	return uint8(v.AuxInt)
+}
+
+func (v *Value) AuxInt16() int16 {
+	if opcodeTable[v.Op].auxType != auxInt16 {
+		v.Fatalf("op %s doesn't have an int16 aux field", v.Op)
+	}
+	return int16(v.AuxInt)
+}
+
+func (v *Value) AuxInt32() int32 {
+	if opcodeTable[v.Op].auxType != auxInt32 {
+		v.Fatalf("op %s doesn't have an int32 aux field", v.Op)
+	}
+	return int32(v.AuxInt)
+}
+
+// AuxUnsigned returns v.AuxInt as an unsigned value for OpConst*.
+// v.AuxInt is always sign-extended to 64 bits, even if the
+// represented value is unsigned. This undoes that sign extension.
+func (v *Value) AuxUnsigned() uint64 {
+	c := v.AuxInt
+	switch v.Op {
+	case OpConst64:
+		return uint64(c)
+	case OpConst32:
+		return uint64(uint32(c))
+	case OpConst16:
+		return uint64(uint16(c))
+	case OpConst8:
+		return uint64(uint8(c))
+	}
+	v.Fatalf("op %s isn't OpConst*", v.Op)
+	return 0
+}
+
+func (v *Value) AuxFloat() float64 {
+	if opcodeTable[v.Op].auxType != auxFloat32 && opcodeTable[v.Op].auxType != auxFloat64 {
+		v.Fatalf("op %s doesn't have a float aux field", v.Op)
+	}
+	return math.Float64frombits(uint64(v.AuxInt))
+}
+func (v *Value) AuxValAndOff() ValAndOff {
+	if opcodeTable[v.Op].auxType != auxSymValAndOff {
+		v.Fatalf("op %s doesn't have a ValAndOff aux field", v.Op)
+	}
+	return ValAndOff(v.AuxInt)
+}
+
+func (v *Value) AuxArm64BitField() arm64BitField {
+	if opcodeTable[v.Op].auxType != auxARM64BitField {
+		v.Fatalf("op %s doesn't have a ValAndOff aux field", v.Op)
+	}
+	return arm64BitField(v.AuxInt)
+}
+
+// long form print.  v# = opcode <type> [aux] args [: reg] (names)
+func (v *Value) LongString() string {
+	if v == nil {
+		return "<NIL VALUE>"
+	}
+	s := fmt.Sprintf("v%d = %s", v.ID, v.Op)
+	s += " <" + v.Type.String() + ">"
+	s += v.auxString()
+	for _, a := range v.Args {
+		s += fmt.Sprintf(" %v", a)
+	}
+	if v.Block == nil {
+		return s
+	}
+	r := v.Block.Func.RegAlloc
+	if int(v.ID) < len(r) && r[v.ID] != nil {
+		s += " : " + r[v.ID].String()
+	}
+	if reg := v.Block.Func.tempRegs[v.ID]; reg != nil {
+		s += " tmp=" + reg.String()
+	}
+	var names []string
+	for name, values := range v.Block.Func.NamedValues {
+		for _, value := range values {
+			if value == v {
+				names = append(names, name.String())
+				break // drop duplicates.
+			}
+		}
+	}
+	if len(names) != 0 {
+		sort.Strings(names) // Otherwise a source of variation in debugging output.
+		s += " (" + strings.Join(names, ", ") + ")"
+	}
+	return s
+}
+
+func (v *Value) auxString() string {
+	switch opcodeTable[v.Op].auxType {
+	case auxBool:
+		if v.AuxInt == 0 {
+			return " [false]"
+		} else {
+			return " [true]"
+		}
+	case auxInt8:
+		return fmt.Sprintf(" [%d]", v.AuxInt8())
+	case auxInt16:
+		return fmt.Sprintf(" [%d]", v.AuxInt16())
+	case auxInt32:
+		return fmt.Sprintf(" [%d]", v.AuxInt32())
+	case auxInt64, auxInt128:
+		return fmt.Sprintf(" [%d]", v.AuxInt)
+	case auxUInt8:
+		return fmt.Sprintf(" [%d]", v.AuxUInt8())
+	case auxARM64BitField:
+		lsb := v.AuxArm64BitField().getARM64BFlsb()
+		width := v.AuxArm64BitField().getARM64BFwidth()
+		return fmt.Sprintf(" [lsb=%d,width=%d]", lsb, width)
+	case auxFloat32, auxFloat64:
+		return fmt.Sprintf(" [%g]", v.AuxFloat())
+	case auxString:
+		return fmt.Sprintf(" {%q}", v.Aux)
+	case auxSym, auxCall, auxTyp:
+		if v.Aux != nil {
+			return fmt.Sprintf(" {%v}", v.Aux)
+		}
+		return ""
+	case auxSymOff, auxCallOff, auxTypSize, auxNameOffsetInt8:
+		s := ""
+		if v.Aux != nil {
+			s = fmt.Sprintf(" {%v}", v.Aux)
+		}
+		if v.AuxInt != 0 || opcodeTable[v.Op].auxType == auxNameOffsetInt8 {
+			s += fmt.Sprintf(" [%v]", v.AuxInt)
+		}
+		return s
+	case auxSymValAndOff:
+		s := ""
+		if v.Aux != nil {
+			s = fmt.Sprintf(" {%v}", v.Aux)
+		}
+		return s + fmt.Sprintf(" [%s]", v.AuxValAndOff())
+	case auxCCop:
+		return fmt.Sprintf(" {%s}", Op(v.AuxInt))
+	case auxS390XCCMask, auxS390XRotateParams:
+		return fmt.Sprintf(" {%v}", v.Aux)
+	case auxFlagConstant:
+		return fmt.Sprintf("[%s]", flagConstant(v.AuxInt))
+	case auxNone:
+		return ""
+	default:
+		// If you see this, add a case above instead.
+		return fmt.Sprintf("[auxtype=%d AuxInt=%d Aux=%v]", opcodeTable[v.Op].auxType, v.AuxInt, v.Aux)
+	}
+}
+
+// If/when midstack inlining is enabled (-l=4), the compiler gets both larger and slower.
+// Not-inlining this method is a help (*Value.reset and *Block.NewValue0 are similar).
+//
+//go:noinline
+func (v *Value) AddArg(w *Value) {
+	if v.Args == nil {
+		v.resetArgs() // use argstorage
+	}
+	v.Args = append(v.Args, w)
+	w.Uses++
+}
+
+//go:noinline
+func (v *Value) AddArg2(w1, w2 *Value) {
+	if v.Args == nil {
+		v.resetArgs() // use argstorage
+	}
+	v.Args = append(v.Args, w1, w2)
+	w1.Uses++
+	w2.Uses++
+}
+
+//go:noinline
+func (v *Value) AddArg3(w1, w2, w3 *Value) {
+	if v.Args == nil {
+		v.resetArgs() // use argstorage
+	}
+	v.Args = append(v.Args, w1, w2, w3)
+	w1.Uses++
+	w2.Uses++
+	w3.Uses++
+}
+
+//go:noinline
+func (v *Value) AddArg4(w1, w2, w3, w4 *Value) {
+	v.Args = append(v.Args, w1, w2, w3, w4)
+	w1.Uses++
+	w2.Uses++
+	w3.Uses++
+	w4.Uses++
+}
+
+//go:noinline
+func (v *Value) AddArg5(w1, w2, w3, w4, w5 *Value) {
+	v.Args = append(v.Args, w1, w2, w3, w4, w5)
+	w1.Uses++
+	w2.Uses++
+	w3.Uses++
+	w4.Uses++
+	w5.Uses++
+}
+
+//go:noinline
+func (v *Value) AddArg6(w1, w2, w3, w4, w5, w6 *Value) {
+	v.Args = append(v.Args, w1, w2, w3, w4, w5, w6)
+	w1.Uses++
+	w2.Uses++
+	w3.Uses++
+	w4.Uses++
+	w5.Uses++
+	w6.Uses++
+}
+
+func (v *Value) AddArgs(a ...*Value) {
+	if v.Args == nil {
+		v.resetArgs() // use argstorage
+	}
+	v.Args = append(v.Args, a...)
+	for _, x := range a {
+		x.Uses++
+	}
+}
+func (v *Value) SetArg(i int, w *Value) {
+	v.Args[i].Uses--
+	v.Args[i] = w
+	w.Uses++
+}
+func (v *Value) SetArgs1(a *Value) {
+	v.resetArgs()
+	v.AddArg(a)
+}
+func (v *Value) SetArgs2(a, b *Value) {
+	v.resetArgs()
+	v.AddArg(a)
+	v.AddArg(b)
+}
+func (v *Value) SetArgs3(a, b, c *Value) {
+	v.resetArgs()
+	v.AddArg(a)
+	v.AddArg(b)
+	v.AddArg(c)
+}
+
+func (v *Value) resetArgs() {
+	for _, a := range v.Args {
+		a.Uses--
+	}
+	v.argstorage[0] = nil
+	v.argstorage[1] = nil
+	v.argstorage[2] = nil
+	v.Args = v.argstorage[:0]
+}
+
+// reset is called from most rewrite rules.
+// Allowing it to be inlined increases the size
+// of cmd/compile by almost 10%, and slows it down.
+//
+//go:noinline
+func (v *Value) reset(op Op) {
+	if v.InCache {
+		v.Block.Func.unCache(v)
+	}
+	v.Op = op
+	v.resetArgs()
+	v.AuxInt = 0
+	v.Aux = nil
+}
+
+// invalidateRecursively marks a value as invalid (unused)
+// and after decrementing reference counts on its Args,
+// also recursively invalidates any of those whose use
+// count goes to zero.  It returns whether any of the
+// invalidated values was marked with IsStmt.
+//
+// BEWARE of doing this *before* you've applied intended
+// updates to SSA.
+func (v *Value) invalidateRecursively() bool {
+	lostStmt := v.Pos.IsStmt() == src.PosIsStmt
+	if v.InCache {
+		v.Block.Func.unCache(v)
+	}
+	v.Op = OpInvalid
+
+	for _, a := range v.Args {
+		a.Uses--
+		if a.Uses == 0 {
+			lost := a.invalidateRecursively()
+			lostStmt = lost || lostStmt
+		}
+	}
+
+	v.argstorage[0] = nil
+	v.argstorage[1] = nil
+	v.argstorage[2] = nil
+	v.Args = v.argstorage[:0]
+
+	v.AuxInt = 0
+	v.Aux = nil
+	return lostStmt
+}
+
+// copyOf is called from rewrite rules.
+// It modifies v to be (Copy a).
+//
+//go:noinline
+func (v *Value) copyOf(a *Value) {
+	if v == a {
+		return
+	}
+	if v.InCache {
+		v.Block.Func.unCache(v)
+	}
+	v.Op = OpCopy
+	v.resetArgs()
+	v.AddArg(a)
+	v.AuxInt = 0
+	v.Aux = nil
+	v.Type = a.Type
+}
+
+// copyInto makes a new value identical to v and adds it to the end of b.
+// unlike copyIntoWithXPos this does not check for v.Pos being a statement.
+func (v *Value) copyInto(b *Block) *Value {
+	c := b.NewValue0(v.Pos.WithNotStmt(), v.Op, v.Type) // Lose the position, this causes line number churn otherwise.
+	c.Aux = v.Aux
+	c.AuxInt = v.AuxInt
+	c.AddArgs(v.Args...)
+	for _, a := range v.Args {
+		if a.Type.IsMemory() {
+			v.Fatalf("can't move a value with a memory arg %s", v.LongString())
+		}
+	}
+	return c
+}
+
+// copyIntoWithXPos makes a new value identical to v and adds it to the end of b.
+// The supplied position is used as the position of the new value.
+// Because this is used for rematerialization, check for case that (rematerialized)
+// input to value with position 'pos' carried a statement mark, and that the supplied
+// position (of the instruction using the rematerialized value) is not marked, and
+// preserve that mark if its line matches the supplied position.
+func (v *Value) copyIntoWithXPos(b *Block, pos src.XPos) *Value {
+	if v.Pos.IsStmt() == src.PosIsStmt && pos.IsStmt() != src.PosIsStmt && v.Pos.SameFileAndLine(pos) {
+		pos = pos.WithIsStmt()
+	}
+	c := b.NewValue0(pos, v.Op, v.Type)
+	c.Aux = v.Aux
+	c.AuxInt = v.AuxInt
+	c.AddArgs(v.Args...)
+	for _, a := range v.Args {
+		if a.Type.IsMemory() {
+			v.Fatalf("can't move a value with a memory arg %s", v.LongString())
+		}
+	}
+	return c
+}
+
+func (v *Value) Logf(msg string, args ...interface{}) { v.Block.Logf(msg, args...) }
+func (v *Value) Log() bool                            { return v.Block.Log() }
+func (v *Value) Fatalf(msg string, args ...interface{}) {
+	v.Block.Func.fe.Fatalf(v.Pos, msg, args...)
+}
+
+// isGenericIntConst reports whether v is a generic integer constant.
+func (v *Value) isGenericIntConst() bool {
+	return v != nil && (v.Op == OpConst64 || v.Op == OpConst32 || v.Op == OpConst16 || v.Op == OpConst8)
+}
+
+// ResultReg returns the result register assigned to v, in cmd/internal/obj/$ARCH numbering.
+// It is similar to Reg and Reg0, except that it is usable interchangeably for all Value Ops.
+// If you know v.Op, using Reg or Reg0 (as appropriate) will be more efficient.
+func (v *Value) ResultReg() int16 {
+	reg := v.Block.Func.RegAlloc[v.ID]
+	if reg == nil {
+		v.Fatalf("nil reg for value: %s\n%s\n", v.LongString(), v.Block.Func)
+	}
+	if pair, ok := reg.(LocPair); ok {
+		reg = pair[0]
+	}
+	if reg == nil {
+		v.Fatalf("nil reg0 for value: %s\n%s\n", v.LongString(), v.Block.Func)
+	}
+	return reg.(*Register).objNum
+}
+
+// Reg returns the register assigned to v, in cmd/internal/obj/$ARCH numbering.
+func (v *Value) Reg() int16 {
+	reg := v.Block.Func.RegAlloc[v.ID]
+	if reg == nil {
+		v.Fatalf("nil register for value: %s\n%s\n", v.LongString(), v.Block.Func)
+	}
+	return reg.(*Register).objNum
+}
+
+// Reg0 returns the register assigned to the first output of v, in cmd/internal/obj/$ARCH numbering.
+func (v *Value) Reg0() int16 {
+	reg := v.Block.Func.RegAlloc[v.ID].(LocPair)[0]
+	if reg == nil {
+		v.Fatalf("nil first register for value: %s\n%s\n", v.LongString(), v.Block.Func)
+	}
+	return reg.(*Register).objNum
+}
+
+// Reg1 returns the register assigned to the second output of v, in cmd/internal/obj/$ARCH numbering.
+func (v *Value) Reg1() int16 {
+	reg := v.Block.Func.RegAlloc[v.ID].(LocPair)[1]
+	if reg == nil {
+		v.Fatalf("nil second register for value: %s\n%s\n", v.LongString(), v.Block.Func)
+	}
+	return reg.(*Register).objNum
+}
+
+// RegTmp returns the temporary register assigned to v, in cmd/internal/obj/$ARCH numbering.
+func (v *Value) RegTmp() int16 {
+	reg := v.Block.Func.tempRegs[v.ID]
+	if reg == nil {
+		v.Fatalf("nil tmp register for value: %s\n%s\n", v.LongString(), v.Block.Func)
+	}
+	return reg.objNum
+}
+
+func (v *Value) RegName() string {
+	reg := v.Block.Func.RegAlloc[v.ID]
+	if reg == nil {
+		v.Fatalf("nil register for value: %s\n%s\n", v.LongString(), v.Block.Func)
+	}
+	return reg.(*Register).name
+}
+
+// MemoryArg returns the memory argument for the Value.
+// The returned value, if non-nil, will be memory-typed (or a tuple with a memory-typed second part).
+// Otherwise, nil is returned.
+func (v *Value) MemoryArg() *Value {
+	if v.Op == OpPhi {
+		v.Fatalf("MemoryArg on Phi")
+	}
+	na := len(v.Args)
+	if na == 0 {
+		return nil
+	}
+	if m := v.Args[na-1]; m.Type.IsMemory() {
+		return m
+	}
+	return nil
+}
+
+// LackingPos indicates whether v is a value that is unlikely to have a correct
+// position assigned to it.  Ignoring such values leads to more user-friendly positions
+// assigned to nearby values and the blocks containing them.
+func (v *Value) LackingPos() bool {
+	// The exact definition of LackingPos is somewhat heuristically defined and may change
+	// in the future, for example if some of these operations are generated more carefully
+	// with respect to their source position.
+	return v.Op == OpVarDef || v.Op == OpVarLive || v.Op == OpPhi ||
+		(v.Op == OpFwdRef || v.Op == OpCopy) && v.Type == types.TypeMem
+}
+
+// removeable reports whether the value v can be removed from the SSA graph entirely
+// if its use count drops to 0.
+func (v *Value) removeable() bool {
+	if v.Type.IsVoid() {
+		// Void ops (inline marks), must stay.
+		return false
+	}
+	if opcodeTable[v.Op].nilCheck {
+		// Nil pointer checks must stay.
+		return false
+	}
+	if v.Type.IsMemory() {
+		// We don't need to preserve all memory ops, but we do need
+		// to keep calls at least (because they might have
+		// synchronization operations we can't see).
+		return false
+	}
+	if v.Op.HasSideEffects() {
+		// These are mostly synchronization operations.
+		return false
+	}
+	return true
+}
+
+// AutoVar returns a *Name and int64 representing the auto variable and offset within it
+// where v should be spilled.
+func AutoVar(v *Value) (*ir.Name, int64) {
+	if loc, ok := v.Block.Func.RegAlloc[v.ID].(LocalSlot); ok {
+		if v.Type.Size() > loc.Type.Size() {
+			v.Fatalf("spill/restore type %s doesn't fit in slot type %s", v.Type, loc.Type)
+		}
+		return loc.N, loc.Off
+	}
+	// Assume it is a register, return its spill slot, which needs to be live
+	nameOff := v.Aux.(*AuxNameOffset)
+	return nameOff.Name, nameOff.Offset
+}
+
+// CanSSA reports whether values of type t can be represented as a Value.
+func CanSSA(t *types.Type) bool {
+	types.CalcSize(t)
+	if t.Size() > int64(4*types.PtrSize) {
+		// 4*Widthptr is an arbitrary constant. We want it
+		// to be at least 3*Widthptr so slices can be registerized.
+		// Too big and we'll introduce too much register pressure.
+		return false
+	}
+	switch t.Kind() {
+	case types.TARRAY:
+		// We can't do larger arrays because dynamic indexing is
+		// not supported on SSA variables.
+		// TODO: allow if all indexes are constant.
+		if t.NumElem() <= 1 {
+			return CanSSA(t.Elem())
+		}
+		return false
+	case types.TSTRUCT:
+		if t.NumFields() > MaxStruct {
+			return false
+		}
+		for _, t1 := range t.Fields() {
+			if !CanSSA(t1.Type) {
+				return false
+			}
+		}
+		return true
+	default:
+		return true
+	}
+}