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// 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/internal/obj"
"fmt"
)
// An Op encodes the specific operation that a Value performs.
// Opcodes' semantics can be modified by the type and aux fields of the Value.
// For instance, OpAdd can be 32 or 64 bit, signed or unsigned, float or complex, depending on Value.Type.
// Semantics of each op are described in the opcode files in gen/*Ops.go.
// There is one file for generic (architecture-independent) ops and one file
// for each architecture.
type Op int32
type opInfo struct {
name string
reg regInfo
auxType auxType
argLen int32 // the number of arguments, -1 if variable length
asm obj.As
generic bool // this is a generic (arch-independent) opcode
rematerializeable bool // this op is rematerializeable
commutative bool // this operation is commutative (e.g. addition)
resultInArg0 bool // (first, if a tuple) output of v and v.Args[0] must be allocated to the same register
resultNotInArgs bool // outputs must not be allocated to the same registers as inputs
clobberFlags bool // this op clobbers flags register
call bool // is a function call
nilCheck bool // this op is a nil check on arg0
faultOnNilArg0 bool // this op will fault if arg0 is nil (and aux encodes a small offset)
faultOnNilArg1 bool // this op will fault if arg1 is nil (and aux encodes a small offset)
usesScratch bool // this op requires scratch memory space
}
type inputInfo struct {
idx int // index in Args array
regs regMask // allowed input registers
}
type outputInfo struct {
idx int // index in output tuple
regs regMask // allowed output registers
}
type regInfo struct {
inputs []inputInfo // ordered in register allocation order
clobbers regMask
outputs []outputInfo // ordered in register allocation order
}
type auxType int8
const (
auxNone auxType = iota
auxBool // auxInt is 0/1 for false/true
auxInt8 // auxInt is an 8-bit integer
auxInt16 // auxInt is a 16-bit integer
auxInt32 // auxInt is a 32-bit integer
auxInt64 // auxInt is a 64-bit integer
auxInt128 // auxInt represents a 128-bit integer. Always 0.
auxFloat32 // auxInt is a float32 (encoded with math.Float64bits)
auxFloat64 // auxInt is a float64 (encoded with math.Float64bits)
auxSizeAndAlign // auxInt is a SizeAndAlign
auxString // aux is a string
auxSym // aux is a symbol
auxSymOff // aux is a symbol, auxInt is an offset
auxSymValAndOff // aux is a symbol, auxInt is a ValAndOff
auxSymSizeAndAlign // aux is a symbol, auxInt is a SizeAndAlign
auxSymInt32 // aux is a symbol, auxInt is a 32-bit integer
)
// A ValAndOff is used by the several opcodes. It holds
// both a value and a pointer offset.
// A ValAndOff is intended to be encoded into an AuxInt field.
// The zero ValAndOff encodes a value of 0 and an offset of 0.
// The high 32 bits hold a value.
// The low 32 bits hold a pointer offset.
type ValAndOff int64
func (x ValAndOff) Val() int64 {
return int64(x) >> 32
}
func (x ValAndOff) Off() int64 {
return int64(int32(x))
}
func (x ValAndOff) Int64() int64 {
return int64(x)
}
func (x ValAndOff) String() string {
return fmt.Sprintf("val=%d,off=%d", x.Val(), x.Off())
}
// validVal reports whether the value can be used
// as an argument to makeValAndOff.
func validVal(val int64) bool {
return val == int64(int32(val))
}
// validOff reports whether the offset can be used
// as an argument to makeValAndOff.
func validOff(off int64) bool {
return off == int64(int32(off))
}
// validValAndOff reports whether we can fit the value and offset into
// a ValAndOff value.
func validValAndOff(val, off int64) bool {
if !validVal(val) {
return false
}
if !validOff(off) {
return false
}
return true
}
// makeValAndOff encodes a ValAndOff into an int64 suitable for storing in an AuxInt field.
func makeValAndOff(val, off int64) int64 {
if !validValAndOff(val, off) {
panic("invalid makeValAndOff")
}
return ValAndOff(val<<32 + int64(uint32(off))).Int64()
}
func (x ValAndOff) canAdd(off int64) bool {
newoff := x.Off() + off
return newoff == int64(int32(newoff))
}
func (x ValAndOff) add(off int64) int64 {
if !x.canAdd(off) {
panic("invalid ValAndOff.add")
}
return makeValAndOff(x.Val(), x.Off()+off)
}
// SizeAndAlign holds both the size and the alignment of a type,
// used in Zero and Move ops.
// The high 8 bits hold the alignment.
// The low 56 bits hold the size.
type SizeAndAlign int64
func (x SizeAndAlign) Size() int64 {
return int64(x) & (1<<56 - 1)
}
func (x SizeAndAlign) Align() int64 {
return int64(uint64(x) >> 56)
}
func (x SizeAndAlign) Int64() int64 {
return int64(x)
}
func (x SizeAndAlign) String() string {
return fmt.Sprintf("size=%d,align=%d", x.Size(), x.Align())
}
func MakeSizeAndAlign(size, align int64) SizeAndAlign {
if size&^(1<<56-1) != 0 {
panic("size too big in SizeAndAlign")
}
if align >= 1<<8 {
panic("alignment too big in SizeAndAlign")
}
return SizeAndAlign(size | align<<56)
}
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