| // 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 ( |
| "fmt" |
| "math" |
| ) |
| |
| // 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 type.go. |
| Type 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). |
| AuxInt int64 |
| Aux interface{} |
| |
| // Arguments of this value |
| Args []*Value |
| |
| // Containing basic block |
| Block *Block |
| |
| // Source line number |
| Line int32 |
| |
| // Use count. Each appearance in Value.Args and Block.Control counts once. |
| Uses int32 |
| |
| // 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 { |
| v.Fatalf("op %s doesn't have an int8 aux field", v.Op) |
| } |
| return int8(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) |
| } |
| |
| 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) |
| } |
| |
| // long form print. v# = opcode <type> [aux] args [: reg] |
| func (v *Value) LongString() string { |
| 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) |
| } |
| r := v.Block.Func.RegAlloc |
| if int(v.ID) < len(r) && r[v.ID] != nil { |
| s += " : " + r[v.ID].Name() |
| } |
| 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 auxSizeAndAlign: |
| return fmt.Sprintf(" [%s]", SizeAndAlign(v.AuxInt)) |
| case auxFloat32, auxFloat64: |
| return fmt.Sprintf(" [%g]", v.AuxFloat()) |
| case auxString: |
| return fmt.Sprintf(" {%q}", v.Aux) |
| case auxSym: |
| if v.Aux != nil { |
| return fmt.Sprintf(" {%v}", v.Aux) |
| } |
| case auxSymOff, auxSymInt32: |
| s := "" |
| if v.Aux != nil { |
| s = fmt.Sprintf(" {%v}", v.Aux) |
| } |
| if v.AuxInt != 0 { |
| 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 auxSymSizeAndAlign: |
| s := "" |
| if v.Aux != nil { |
| s = fmt.Sprintf(" {%v}", v.Aux) |
| } |
| return s + fmt.Sprintf(" [%s]", SizeAndAlign(v.AuxInt)) |
| } |
| return "" |
| } |
| |
| func (v *Value) AddArg(w *Value) { |
| if v.Args == nil { |
| v.resetArgs() // use argstorage |
| } |
| v.Args = append(v.Args, w) |
| w.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) RemoveArg(i int) { |
| v.Args[i].Uses-- |
| copy(v.Args[i:], v.Args[i+1:]) |
| v.Args[len(v.Args)-1] = nil // aid GC |
| v.Args = v.Args[:len(v.Args)-1] |
| } |
| func (v *Value) SetArgs1(a *Value) { |
| v.resetArgs() |
| v.AddArg(a) |
| } |
| func (v *Value) SetArgs2(a *Value, b *Value) { |
| v.resetArgs() |
| v.AddArg(a) |
| v.AddArg(b) |
| } |
| |
| 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] |
| } |
| |
| func (v *Value) reset(op Op) { |
| v.Op = op |
| v.resetArgs() |
| v.AuxInt = 0 |
| v.Aux = nil |
| } |
| |
| // copyInto makes a new value identical to v and adds it to the end of b. |
| func (v *Value) copyInto(b *Block) *Value { |
| c := b.NewValue0(v.Line, 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.Config.Fatalf(v.Line, msg, args...) |
| } |
| |
| // isGenericIntConst returns 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) |
| } |
| |
| // ExternSymbol is an aux value that encodes a variable's |
| // constant offset from the static base pointer. |
| type ExternSymbol struct { |
| Typ Type // Go type |
| Sym fmt.Stringer // A *gc.Sym referring to a global variable |
| // Note: the offset for an external symbol is not |
| // calculated until link time. |
| } |
| |
| // ArgSymbol is an aux value that encodes an argument or result |
| // variable's constant offset from FP (FP = SP + framesize). |
| type ArgSymbol struct { |
| Typ Type // Go type |
| Node GCNode // A *gc.Node referring to the argument/result variable. |
| } |
| |
| // AutoSymbol is an aux value that encodes a local variable's |
| // constant offset from SP. |
| type AutoSymbol struct { |
| Typ Type // Go type |
| Node GCNode // A *gc.Node referring to a local (auto) variable. |
| } |
| |
| func (s *ExternSymbol) String() string { |
| return s.Sym.String() |
| } |
| |
| func (s *ArgSymbol) String() string { |
| return s.Node.String() |
| } |
| |
| func (s *AutoSymbol) String() string { |
| return s.Node.String() |
| } |
| |
| // 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 |
| } |
| |
| 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 |
| } |
