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go/src/cmd/compile/internal/x86/ssa.go
Keith Randall c069bc4996 [dev.ssa] cmd/compile: implement GO386=387 
Last part of the 386 SSA port.

Modify the x86 backend to simulate SSE registers and
instructions with 387 registers and instructions.
The simulation isn't terribly performant, but it works,
and the old implementation wasn't very performant either.
Leaving to people who care about 387 to optimize if they want.

Turn on SSA backend for 386 by default.

Fixes #16358

Change-Id: I678fb59132620b2c47e993c1c10c4c21135f70c0
Reviewed-on: https://go-review.googlesource.com/25271
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
2016-08-10 17:41:01 +00:00

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// Copyright 2016 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 x86
import (
"fmt"
"math"
"cmd/compile/internal/gc"
"cmd/compile/internal/ssa"
"cmd/internal/obj"
"cmd/internal/obj/x86"
)
// Smallest possible faulting page at address zero.
const minZeroPage = 4096
// ssaRegToReg maps ssa register numbers to obj register numbers.
var ssaRegToReg = []int16{
x86.REG_AX,
x86.REG_CX,
x86.REG_DX,
x86.REG_BX,
x86.REG_SP,
x86.REG_BP,
x86.REG_SI,
x86.REG_DI,
x86.REG_X0,
x86.REG_X1,
x86.REG_X2,
x86.REG_X3,
x86.REG_X4,
x86.REG_X5,
x86.REG_X6,
x86.REG_X7,
0, // SB isn't a real register. We fill an Addr.Reg field with 0 in this case.
}
// markMoves marks any MOVXconst ops that need to avoid clobbering flags.
func ssaMarkMoves(s *gc.SSAGenState, b *ssa.Block) {
flive := b.FlagsLiveAtEnd
if b.Control != nil && b.Control.Type.IsFlags() {
flive = true
}
for i := len(b.Values) - 1; i >= 0; i-- {
v := b.Values[i]
if flive && v.Op == ssa.Op386MOVLconst {
// The "mark" is any non-nil Aux value.
v.Aux = v
}
if v.Type.IsFlags() {
flive = false
}
for _, a := range v.Args {
if a.Type.IsFlags() {
flive = true
}
}
}
}
// loadByType returns the load instruction of the given type.
func loadByType(t ssa.Type) obj.As {
// Avoid partial register write
if !t.IsFloat() && t.Size() <= 2 {
if t.Size() == 1 {
return x86.AMOVBLZX
} else {
return x86.AMOVWLZX
}
}
// Otherwise, there's no difference between load and store opcodes.
return storeByType(t)
}
// storeByType returns the store instruction of the given type.
func storeByType(t ssa.Type) obj.As {
width := t.Size()
if t.IsFloat() {
switch width {
case 4:
return x86.AMOVSS
case 8:
return x86.AMOVSD
}
} else {
switch width {
case 1:
return x86.AMOVB
case 2:
return x86.AMOVW
case 4:
return x86.AMOVL
}
}
panic("bad store type")
}
// moveByType returns the reg->reg move instruction of the given type.
func moveByType(t ssa.Type) obj.As {
if t.IsFloat() {
switch t.Size() {
case 4:
return x86.AMOVSS
case 8:
return x86.AMOVSD
default:
panic(fmt.Sprintf("bad float register width %d:%s", t.Size(), t))
}
} else {
switch t.Size() {
case 1:
// Avoids partial register write
return x86.AMOVL
case 2:
return x86.AMOVL
case 4:
return x86.AMOVL
default:
panic(fmt.Sprintf("bad int register width %d:%s", t.Size(), t))
}
}
}
// opregreg emits instructions for
// dest := dest(To) op src(From)
// and also returns the created obj.Prog so it
// may be further adjusted (offset, scale, etc).
func opregreg(op obj.As, dest, src int16) *obj.Prog {
p := gc.Prog(op)
p.From.Type = obj.TYPE_REG
p.To.Type = obj.TYPE_REG
p.To.Reg = dest
p.From.Reg = src
return p
}
func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
s.SetLineno(v.Line)
if gc.Thearch.Use387 {
if ssaGenValue387(s, v) {
return // v was handled by 387 generation.
}
}
switch v.Op {
case ssa.Op386ADDL:
r := gc.SSARegNum(v)
r1 := gc.SSARegNum(v.Args[0])
r2 := gc.SSARegNum(v.Args[1])
switch {
case r == r1:
p := gc.Prog(v.Op.Asm())
p.From.Type = obj.TYPE_REG
p.From.Reg = r2
p.To.Type = obj.TYPE_REG
p.To.Reg = r
case r == r2:
p := gc.Prog(v.Op.Asm())
p.From.Type = obj.TYPE_REG
p.From.Reg = r1
p.To.Type = obj.TYPE_REG
p.To.Reg = r
default:
p := gc.Prog(x86.ALEAL)
p.From.Type = obj.TYPE_MEM
p.From.Reg = r1
p.From.Scale = 1
p.From.Index = r2
p.To.Type = obj.TYPE_REG
p.To.Reg = r
}
// 2-address opcode arithmetic
case ssa.Op386SUBL,
ssa.Op386MULL,
ssa.Op386ANDL,
ssa.Op386ORL,
ssa.Op386XORL,
ssa.Op386SHLL,
ssa.Op386SHRL, ssa.Op386SHRW, ssa.Op386SHRB,
ssa.Op386SARL, ssa.Op386SARW, ssa.Op386SARB,
ssa.Op386ADDSS, ssa.Op386ADDSD, ssa.Op386SUBSS, ssa.Op386SUBSD,
ssa.Op386MULSS, ssa.Op386MULSD, ssa.Op386DIVSS, ssa.Op386DIVSD,
ssa.Op386PXOR,
ssa.Op386ADCL,
ssa.Op386SBBL:
r := gc.SSARegNum(v)
if r != gc.SSARegNum(v.Args[0]) {
v.Fatalf("input[0] and output not in same register %s", v.LongString())
}
opregreg(v.Op.Asm(), r, gc.SSARegNum(v.Args[1]))
case ssa.Op386ADDLcarry, ssa.Op386SUBLcarry:
// output 0 is carry/borrow, output 1 is the low 32 bits.
r := gc.SSARegNum1(v)
if r != gc.SSARegNum(v.Args[0]) {
v.Fatalf("input[0] and output[1] not in same register %s", v.LongString())
}
opregreg(v.Op.Asm(), r, gc.SSARegNum(v.Args[1]))
case ssa.Op386ADDLconstcarry, ssa.Op386SUBLconstcarry:
// output 0 is carry/borrow, output 1 is the low 32 bits.
r := gc.SSARegNum1(v)
if r != gc.SSARegNum(v.Args[0]) {
v.Fatalf("input[0] and output[1] not in same register %s", v.LongString())
}
p := gc.Prog(v.Op.Asm())
p.From.Type = obj.TYPE_CONST
p.From.Offset = v.AuxInt
p.To.Type = obj.TYPE_REG
p.To.Reg = r
case ssa.Op386DIVL, ssa.Op386DIVW,
ssa.Op386DIVLU, ssa.Op386DIVWU,
ssa.Op386MODL, ssa.Op386MODW,
ssa.Op386MODLU, ssa.Op386MODWU:
// Arg[0] is already in AX as it's the only register we allow
// and AX is the only output
x := gc.SSARegNum(v.Args[1])
// CPU faults upon signed overflow, which occurs when most
// negative int is divided by -1.
var j *obj.Prog
if v.Op == ssa.Op386DIVL || v.Op == ssa.Op386DIVW ||
v.Op == ssa.Op386MODL || v.Op == ssa.Op386MODW {
var c *obj.Prog
switch v.Op {
case ssa.Op386DIVL, ssa.Op386MODL:
c = gc.Prog(x86.ACMPL)
j = gc.Prog(x86.AJEQ)
gc.Prog(x86.ACDQ) //TODO: fix
case ssa.Op386DIVW, ssa.Op386MODW:
c = gc.Prog(x86.ACMPW)
j = gc.Prog(x86.AJEQ)
gc.Prog(x86.ACWD)
}
c.From.Type = obj.TYPE_REG
c.From.Reg = x
c.To.Type = obj.TYPE_CONST
c.To.Offset = -1
j.To.Type = obj.TYPE_BRANCH
}
// for unsigned ints, we sign extend by setting DX = 0
// signed ints were sign extended above
if v.Op == ssa.Op386DIVLU || v.Op == ssa.Op386MODLU ||
v.Op == ssa.Op386DIVWU || v.Op == ssa.Op386MODWU {
c := gc.Prog(x86.AXORL)
c.From.Type = obj.TYPE_REG
c.From.Reg = x86.REG_DX
c.To.Type = obj.TYPE_REG
c.To.Reg = x86.REG_DX
}
p := gc.Prog(v.Op.Asm())
p.From.Type = obj.TYPE_REG
p.From.Reg = x
// signed division, rest of the check for -1 case
if j != nil {
j2 := gc.Prog(obj.AJMP)
j2.To.Type = obj.TYPE_BRANCH
var n *obj.Prog
if v.Op == ssa.Op386DIVL || v.Op == ssa.Op386DIVW {
// n * -1 = -n
n = gc.Prog(x86.ANEGL)
n.To.Type = obj.TYPE_REG
n.To.Reg = x86.REG_AX
} else {
// n % -1 == 0
n = gc.Prog(x86.AXORL)
n.From.Type = obj.TYPE_REG
n.From.Reg = x86.REG_DX
n.To.Type = obj.TYPE_REG
n.To.Reg = x86.REG_DX
}
j.To.Val = n
j2.To.Val = s.Pc()
}
case ssa.Op386HMULL, ssa.Op386HMULW, ssa.Op386HMULB,
ssa.Op386HMULLU, ssa.Op386HMULWU, ssa.Op386HMULBU:
// the frontend rewrites constant division by 8/16/32 bit integers into
// HMUL by a constant
// SSA rewrites generate the 64 bit versions
// Arg[0] is already in AX as it's the only register we allow
// and DX is the only output we care about (the high bits)
p := gc.Prog(v.Op.Asm())
p.From.Type = obj.TYPE_REG
p.From.Reg = gc.SSARegNum(v.Args[1])
// IMULB puts the high portion in AH instead of DL,
// so move it to DL for consistency
if v.Type.Size() == 1 {
m := gc.Prog(x86.AMOVB)
m.From.Type = obj.TYPE_REG
m.From.Reg = x86.REG_AH
m.To.Type = obj.TYPE_REG
m.To.Reg = x86.REG_DX
}
case ssa.Op386MULLQU:
// AX * args[1], high 32 bits in DX (result[0]), low 32 bits in AX (result[1]).
p := gc.Prog(v.Op.Asm())
p.From.Type = obj.TYPE_REG
p.From.Reg = gc.SSARegNum(v.Args[1])
case ssa.Op386ADDLconst:
r := gc.SSARegNum(v)
a := gc.SSARegNum(v.Args[0])
if r == a {
if v.AuxInt == 1 {
p := gc.Prog(x86.AINCL)
p.To.Type = obj.TYPE_REG
p.To.Reg = r
return
}
if v.AuxInt == -1 {
p := gc.Prog(x86.ADECL)
p.To.Type = obj.TYPE_REG
p.To.Reg = r
return
}
p := gc.Prog(v.Op.Asm())
p.From.Type = obj.TYPE_CONST
p.From.Offset = v.AuxInt
p.To.Type = obj.TYPE_REG
p.To.Reg = r
return
}
p := gc.Prog(x86.ALEAL)
p.From.Type = obj.TYPE_MEM
p.From.Reg = a
p.From.Offset = v.AuxInt
p.To.Type = obj.TYPE_REG
p.To.Reg = r
case ssa.Op386MULLconst:
r := gc.SSARegNum(v)
if r != gc.SSARegNum(v.Args[0]) {
v.Fatalf("input[0] and output not in same register %s", v.LongString())
}
p := gc.Prog(v.Op.Asm())
p.From.Type = obj.TYPE_CONST
p.From.Offset = v.AuxInt
p.To.Type = obj.TYPE_REG
p.To.Reg = r
// TODO: Teach doasm to compile the three-address multiply imul $c, r1, r2
// then we don't need to use resultInArg0 for these ops.
//p.From3 = new(obj.Addr)
//p.From3.Type = obj.TYPE_REG
//p.From3.Reg = gc.SSARegNum(v.Args[0])
case ssa.Op386SUBLconst,
ssa.Op386ADCLconst,
ssa.Op386SBBLconst,
ssa.Op386ANDLconst,
ssa.Op386ORLconst,
ssa.Op386XORLconst,
ssa.Op386SHLLconst,
ssa.Op386SHRLconst, ssa.Op386SHRWconst, ssa.Op386SHRBconst,
ssa.Op386SARLconst, ssa.Op386SARWconst, ssa.Op386SARBconst,
ssa.Op386ROLLconst, ssa.Op386ROLWconst, ssa.Op386ROLBconst:
r := gc.SSARegNum(v)
if r != gc.SSARegNum(v.Args[0]) {
v.Fatalf("input[0] and output not in same register %s", v.LongString())
}
p := gc.Prog(v.Op.Asm())
p.From.Type = obj.TYPE_CONST
p.From.Offset = v.AuxInt
p.To.Type = obj.TYPE_REG
p.To.Reg = r
case ssa.Op386SBBLcarrymask:
r := gc.SSARegNum(v)
p := gc.Prog(v.Op.Asm())
p.From.Type = obj.TYPE_REG
p.From.Reg = r
p.To.Type = obj.TYPE_REG
p.To.Reg = r
case ssa.Op386LEAL1, ssa.Op386LEAL2, ssa.Op386LEAL4, ssa.Op386LEAL8:
r := gc.SSARegNum(v.Args[0])
i := gc.SSARegNum(v.Args[1])
p := gc.Prog(x86.ALEAL)
switch v.Op {
case ssa.Op386LEAL1:
p.From.Scale = 1
if i == x86.REG_SP {
r, i = i, r
}
case ssa.Op386LEAL2:
p.From.Scale = 2
case ssa.Op386LEAL4:
p.From.Scale = 4
case ssa.Op386LEAL8:
p.From.Scale = 8
}
p.From.Type = obj.TYPE_MEM
p.From.Reg = r
p.From.Index = i
gc.AddAux(&p.From, v)
p.To.Type = obj.TYPE_REG
p.To.Reg = gc.SSARegNum(v)
case ssa.Op386LEAL:
p := gc.Prog(x86.ALEAL)
p.From.Type = obj.TYPE_MEM
p.From.Reg = gc.SSARegNum(v.Args[0])
gc.AddAux(&p.From, v)
p.To.Type = obj.TYPE_REG
p.To.Reg = gc.SSARegNum(v)
case ssa.Op386CMPL, ssa.Op386CMPW, ssa.Op386CMPB,
ssa.Op386TESTL, ssa.Op386TESTW, ssa.Op386TESTB:
opregreg(v.Op.Asm(), gc.SSARegNum(v.Args[1]), gc.SSARegNum(v.Args[0]))
case ssa.Op386UCOMISS, ssa.Op386UCOMISD:
// Go assembler has swapped operands for UCOMISx relative to CMP,
// must account for that right here.
opregreg(v.Op.Asm(), gc.SSARegNum(v.Args[0]), gc.SSARegNum(v.Args[1]))
case ssa.Op386CMPLconst, ssa.Op386CMPWconst, ssa.Op386CMPBconst:
p := gc.Prog(v.Op.Asm())
p.From.Type = obj.TYPE_REG
p.From.Reg = gc.SSARegNum(v.Args[0])
p.To.Type = obj.TYPE_CONST
p.To.Offset = v.AuxInt
case ssa.Op386TESTLconst, ssa.Op386TESTWconst, ssa.Op386TESTBconst:
p := gc.Prog(v.Op.Asm())
p.From.Type = obj.TYPE_CONST
p.From.Offset = v.AuxInt
p.To.Type = obj.TYPE_REG
p.To.Reg = gc.SSARegNum(v.Args[0])
case ssa.Op386MOVLconst:
x := gc.SSARegNum(v)
p := gc.Prog(v.Op.Asm())
p.From.Type = obj.TYPE_CONST
p.From.Offset = v.AuxInt
p.To.Type = obj.TYPE_REG
p.To.Reg = x
// If flags are live at this instruction, suppress the
// MOV $0,AX -> XOR AX,AX optimization.
if v.Aux != nil {
p.Mark |= x86.PRESERVEFLAGS
}
case ssa.Op386MOVSSconst, ssa.Op386MOVSDconst:
x := gc.SSARegNum(v)
p := gc.Prog(v.Op.Asm())
p.From.Type = obj.TYPE_FCONST
p.From.Val = math.Float64frombits(uint64(v.AuxInt))
p.To.Type = obj.TYPE_REG
p.To.Reg = x
case ssa.Op386MOVSSload, ssa.Op386MOVSDload, ssa.Op386MOVLload, ssa.Op386MOVWload, ssa.Op386MOVBload, ssa.Op386MOVBLSXload, ssa.Op386MOVWLSXload:
p := gc.Prog(v.Op.Asm())
p.From.Type = obj.TYPE_MEM
p.From.Reg = gc.SSARegNum(v.Args[0])
gc.AddAux(&p.From, v)
p.To.Type = obj.TYPE_REG
p.To.Reg = gc.SSARegNum(v)
case ssa.Op386MOVSDloadidx8:
p := gc.Prog(v.Op.Asm())
p.From.Type = obj.TYPE_MEM
p.From.Reg = gc.SSARegNum(v.Args[0])
gc.AddAux(&p.From, v)
p.From.Scale = 8
p.From.Index = gc.SSARegNum(v.Args[1])
p.To.Type = obj.TYPE_REG
p.To.Reg = gc.SSARegNum(v)
case ssa.Op386MOVLloadidx4, ssa.Op386MOVSSloadidx4:
p := gc.Prog(v.Op.Asm())
p.From.Type = obj.TYPE_MEM
p.From.Reg = gc.SSARegNum(v.Args[0])
gc.AddAux(&p.From, v)
p.From.Scale = 4
p.From.Index = gc.SSARegNum(v.Args[1])
p.To.Type = obj.TYPE_REG
p.To.Reg = gc.SSARegNum(v)
case ssa.Op386MOVWloadidx2:
p := gc.Prog(v.Op.Asm())
p.From.Type = obj.TYPE_MEM
p.From.Reg = gc.SSARegNum(v.Args[0])
gc.AddAux(&p.From, v)
p.From.Scale = 2
p.From.Index = gc.SSARegNum(v.Args[1])
p.To.Type = obj.TYPE_REG
p.To.Reg = gc.SSARegNum(v)
case ssa.Op386MOVBloadidx1, ssa.Op386MOVWloadidx1, ssa.Op386MOVLloadidx1, ssa.Op386MOVSSloadidx1, ssa.Op386MOVSDloadidx1:
r := gc.SSARegNum(v.Args[0])
i := gc.SSARegNum(v.Args[1])
if i == x86.REG_SP {
r, i = i, r
}
p := gc.Prog(v.Op.Asm())
p.From.Type = obj.TYPE_MEM
p.From.Reg = r
p.From.Scale = 1
p.From.Index = i
gc.AddAux(&p.From, v)
p.To.Type = obj.TYPE_REG
p.To.Reg = gc.SSARegNum(v)
case ssa.Op386MOVSSstore, ssa.Op386MOVSDstore, ssa.Op386MOVLstore, ssa.Op386MOVWstore, ssa.Op386MOVBstore:
p := gc.Prog(v.Op.Asm())
p.From.Type = obj.TYPE_REG
p.From.Reg = gc.SSARegNum(v.Args[1])
p.To.Type = obj.TYPE_MEM
p.To.Reg = gc.SSARegNum(v.Args[0])
gc.AddAux(&p.To, v)
case ssa.Op386MOVSDstoreidx8:
p := gc.Prog(v.Op.Asm())
p.From.Type = obj.TYPE_REG
p.From.Reg = gc.SSARegNum(v.Args[2])
p.To.Type = obj.TYPE_MEM
p.To.Reg = gc.SSARegNum(v.Args[0])
p.To.Scale = 8
p.To.Index = gc.SSARegNum(v.Args[1])
gc.AddAux(&p.To, v)
case ssa.Op386MOVSSstoreidx4, ssa.Op386MOVLstoreidx4:
p := gc.Prog(v.Op.Asm())
p.From.Type = obj.TYPE_REG
p.From.Reg = gc.SSARegNum(v.Args[2])
p.To.Type = obj.TYPE_MEM
p.To.Reg = gc.SSARegNum(v.Args[0])
p.To.Scale = 4
p.To.Index = gc.SSARegNum(v.Args[1])
gc.AddAux(&p.To, v)
case ssa.Op386MOVWstoreidx2:
p := gc.Prog(v.Op.Asm())
p.From.Type = obj.TYPE_REG
p.From.Reg = gc.SSARegNum(v.Args[2])
p.To.Type = obj.TYPE_MEM
p.To.Reg = gc.SSARegNum(v.Args[0])
p.To.Scale = 2
p.To.Index = gc.SSARegNum(v.Args[1])
gc.AddAux(&p.To, v)
case ssa.Op386MOVBstoreidx1, ssa.Op386MOVWstoreidx1, ssa.Op386MOVLstoreidx1, ssa.Op386MOVSSstoreidx1, ssa.Op386MOVSDstoreidx1:
r := gc.SSARegNum(v.Args[0])
i := gc.SSARegNum(v.Args[1])
if i == x86.REG_SP {
r, i = i, r
}
p := gc.Prog(v.Op.Asm())
p.From.Type = obj.TYPE_REG
p.From.Reg = gc.SSARegNum(v.Args[2])
p.To.Type = obj.TYPE_MEM
p.To.Reg = r
p.To.Scale = 1
p.To.Index = i
gc.AddAux(&p.To, v)
case ssa.Op386MOVLstoreconst, ssa.Op386MOVWstoreconst, ssa.Op386MOVBstoreconst:
p := gc.Prog(v.Op.Asm())
p.From.Type = obj.TYPE_CONST
sc := v.AuxValAndOff()
p.From.Offset = sc.Val()
p.To.Type = obj.TYPE_MEM
p.To.Reg = gc.SSARegNum(v.Args[0])
gc.AddAux2(&p.To, v, sc.Off())
case ssa.Op386MOVLstoreconstidx1, ssa.Op386MOVLstoreconstidx4, ssa.Op386MOVWstoreconstidx1, ssa.Op386MOVWstoreconstidx2, ssa.Op386MOVBstoreconstidx1:
p := gc.Prog(v.Op.Asm())
p.From.Type = obj.TYPE_CONST
sc := v.AuxValAndOff()
p.From.Offset = sc.Val()
r := gc.SSARegNum(v.Args[0])
i := gc.SSARegNum(v.Args[1])
switch v.Op {
case ssa.Op386MOVBstoreconstidx1, ssa.Op386MOVWstoreconstidx1, ssa.Op386MOVLstoreconstidx1:
p.To.Scale = 1
if i == x86.REG_SP {
r, i = i, r
}
case ssa.Op386MOVWstoreconstidx2:
p.To.Scale = 2
case ssa.Op386MOVLstoreconstidx4:
p.To.Scale = 4
}
p.To.Type = obj.TYPE_MEM
p.To.Reg = r
p.To.Index = i
gc.AddAux2(&p.To, v, sc.Off())
case ssa.Op386MOVWLSX, ssa.Op386MOVBLSX, ssa.Op386MOVWLZX, ssa.Op386MOVBLZX,
ssa.Op386CVTSL2SS, ssa.Op386CVTSL2SD,
ssa.Op386CVTTSS2SL, ssa.Op386CVTTSD2SL,
ssa.Op386CVTSS2SD, ssa.Op386CVTSD2SS:
opregreg(v.Op.Asm(), gc.SSARegNum(v), gc.SSARegNum(v.Args[0]))
case ssa.Op386DUFFZERO:
p := gc.Prog(obj.ADUFFZERO)
p.To.Type = obj.TYPE_ADDR
p.To.Sym = gc.Linksym(gc.Pkglookup("duffzero", gc.Runtimepkg))
p.To.Offset = v.AuxInt
case ssa.Op386DUFFCOPY:
p := gc.Prog(obj.ADUFFCOPY)
p.To.Type = obj.TYPE_ADDR
p.To.Sym = gc.Linksym(gc.Pkglookup("duffcopy", gc.Runtimepkg))
p.To.Offset = v.AuxInt
case ssa.OpCopy, ssa.Op386MOVLconvert: // TODO: use MOVLreg for reg->reg copies instead of OpCopy?
if v.Type.IsMemory() {
return
}
x := gc.SSARegNum(v.Args[0])
y := gc.SSARegNum(v)
if x != y {
opregreg(moveByType(v.Type), y, x)
}
case ssa.OpLoadReg:
if v.Type.IsFlags() {
v.Unimplementedf("load flags not implemented: %v", v.LongString())
return
}
p := gc.Prog(loadByType(v.Type))
n, off := gc.AutoVar(v.Args[0])
p.From.Type = obj.TYPE_MEM
p.From.Node = n
p.From.Sym = gc.Linksym(n.Sym)
p.From.Offset = off
if n.Class == gc.PPARAM || n.Class == gc.PPARAMOUT {
p.From.Name = obj.NAME_PARAM
p.From.Offset += n.Xoffset
} else {
p.From.Name = obj.NAME_AUTO
}
p.To.Type = obj.TYPE_REG
p.To.Reg = gc.SSARegNum(v)
case ssa.OpStoreReg:
if v.Type.IsFlags() {
v.Unimplementedf("store flags not implemented: %v", v.LongString())
return
}
p := gc.Prog(storeByType(v.Type))
p.From.Type = obj.TYPE_REG
p.From.Reg = gc.SSARegNum(v.Args[0])
n, off := gc.AutoVar(v)
p.To.Type = obj.TYPE_MEM
p.To.Node = n
p.To.Sym = gc.Linksym(n.Sym)
p.To.Offset = off
if n.Class == gc.PPARAM || n.Class == gc.PPARAMOUT {
p.To.Name = obj.NAME_PARAM
p.To.Offset += n.Xoffset
} else {
p.To.Name = obj.NAME_AUTO
}
case ssa.OpPhi:
gc.CheckLoweredPhi(v)
case ssa.OpInitMem:
// memory arg needs no code
case ssa.OpArg:
// input args need no code
case ssa.Op386LoweredGetClosurePtr:
// Closure pointer is DX.
gc.CheckLoweredGetClosurePtr(v)
case ssa.Op386LoweredGetG:
r := gc.SSARegNum(v)
// See the comments in cmd/internal/obj/x86/obj6.go
// near CanUse1InsnTLS for a detailed explanation of these instructions.
if x86.CanUse1InsnTLS(gc.Ctxt) {
// MOVL (TLS), r
p := gc.Prog(x86.AMOVL)
p.From.Type = obj.TYPE_MEM
p.From.Reg = x86.REG_TLS
p.To.Type = obj.TYPE_REG
p.To.Reg = r
} else {
// MOVL TLS, r
// MOVL (r)(TLS*1), r
p := gc.Prog(x86.AMOVL)
p.From.Type = obj.TYPE_REG
p.From.Reg = x86.REG_TLS
p.To.Type = obj.TYPE_REG
p.To.Reg = r
q := gc.Prog(x86.AMOVL)
q.From.Type = obj.TYPE_MEM
q.From.Reg = r
q.From.Index = x86.REG_TLS
q.From.Scale = 1
q.To.Type = obj.TYPE_REG
q.To.Reg = r
}
case ssa.Op386CALLstatic:
if v.Aux.(*gc.Sym) == gc.Deferreturn.Sym {
// Deferred calls will appear to be returning to
// the CALL deferreturn(SB) that we are about to emit.
// However, the stack trace code will show the line
// of the instruction byte before the return PC.
// To avoid that being an unrelated instruction,
// insert an actual hardware NOP that will have the right line number.
// This is different from obj.ANOP, which is a virtual no-op
// that doesn't make it into the instruction stream.
ginsnop()
}
p := gc.Prog(obj.ACALL)
p.To.Type = obj.TYPE_MEM
p.To.Name = obj.NAME_EXTERN
p.To.Sym = gc.Linksym(v.Aux.(*gc.Sym))
if gc.Maxarg < v.AuxInt {
gc.Maxarg = v.AuxInt
}
case ssa.Op386CALLclosure:
p := gc.Prog(obj.ACALL)
p.To.Type = obj.TYPE_REG
p.To.Reg = gc.SSARegNum(v.Args[0])
if gc.Maxarg < v.AuxInt {
gc.Maxarg = v.AuxInt
}
case ssa.Op386CALLdefer:
p := gc.Prog(obj.ACALL)
p.To.Type = obj.TYPE_MEM
p.To.Name = obj.NAME_EXTERN
p.To.Sym = gc.Linksym(gc.Deferproc.Sym)
if gc.Maxarg < v.AuxInt {
gc.Maxarg = v.AuxInt
}
case ssa.Op386CALLgo:
p := gc.Prog(obj.ACALL)
p.To.Type = obj.TYPE_MEM
p.To.Name = obj.NAME_EXTERN
p.To.Sym = gc.Linksym(gc.Newproc.Sym)
if gc.Maxarg < v.AuxInt {
gc.Maxarg = v.AuxInt
}
case ssa.Op386CALLinter:
p := gc.Prog(obj.ACALL)
p.To.Type = obj.TYPE_REG
p.To.Reg = gc.SSARegNum(v.Args[0])
if gc.Maxarg < v.AuxInt {
gc.Maxarg = v.AuxInt
}
case ssa.Op386NEGL,
ssa.Op386BSWAPL,
ssa.Op386NOTL:
r := gc.SSARegNum(v)
if r != gc.SSARegNum(v.Args[0]) {
v.Fatalf("input[0] and output not in same register %s", v.LongString())
}
p := gc.Prog(v.Op.Asm())
p.To.Type = obj.TYPE_REG
p.To.Reg = r
case ssa.Op386BSFL, ssa.Op386BSFW,
ssa.Op386BSRL, ssa.Op386BSRW,
ssa.Op386SQRTSD:
p := gc.Prog(v.Op.Asm())
p.From.Type = obj.TYPE_REG
p.From.Reg = gc.SSARegNum(v.Args[0])
p.To.Type = obj.TYPE_REG
p.To.Reg = gc.SSARegNum(v)
case ssa.OpSP, ssa.OpSB, ssa.OpSelect0, ssa.OpSelect1:
// nothing to do
case ssa.Op386SETEQ, ssa.Op386SETNE,
ssa.Op386SETL, ssa.Op386SETLE,
ssa.Op386SETG, ssa.Op386SETGE,
ssa.Op386SETGF, ssa.Op386SETGEF,
ssa.Op386SETB, ssa.Op386SETBE,
ssa.Op386SETORD, ssa.Op386SETNAN,
ssa.Op386SETA, ssa.Op386SETAE:
p := gc.Prog(v.Op.Asm())
p.To.Type = obj.TYPE_REG
p.To.Reg = gc.SSARegNum(v)
case ssa.Op386SETNEF:
p := gc.Prog(v.Op.Asm())
p.To.Type = obj.TYPE_REG
p.To.Reg = gc.SSARegNum(v)
q := gc.Prog(x86.ASETPS)
q.To.Type = obj.TYPE_REG
q.To.Reg = x86.REG_AX
opregreg(x86.AORL, gc.SSARegNum(v), x86.REG_AX)
case ssa.Op386SETEQF:
p := gc.Prog(v.Op.Asm())
p.To.Type = obj.TYPE_REG
p.To.Reg = gc.SSARegNum(v)
q := gc.Prog(x86.ASETPC)
q.To.Type = obj.TYPE_REG
q.To.Reg = x86.REG_AX
opregreg(x86.AANDL, gc.SSARegNum(v), x86.REG_AX)
case ssa.Op386InvertFlags:
v.Fatalf("InvertFlags should never make it to codegen %v", v.LongString())
case ssa.Op386FlagEQ, ssa.Op386FlagLT_ULT, ssa.Op386FlagLT_UGT, ssa.Op386FlagGT_ULT, ssa.Op386FlagGT_UGT:
v.Fatalf("Flag* ops should never make it to codegen %v", v.LongString())
case ssa.Op386REPSTOSL:
gc.Prog(x86.AREP)
gc.Prog(x86.ASTOSL)
case ssa.Op386REPMOVSL:
gc.Prog(x86.AREP)
gc.Prog(x86.AMOVSL)
case ssa.OpVarDef:
gc.Gvardef(v.Aux.(*gc.Node))
case ssa.OpVarKill:
gc.Gvarkill(v.Aux.(*gc.Node))
case ssa.OpVarLive:
gc.Gvarlive(v.Aux.(*gc.Node))
case ssa.OpKeepAlive:
if !v.Args[0].Type.IsPtrShaped() {
v.Fatalf("keeping non-pointer alive %v", v.Args[0])
}
n, off := gc.AutoVar(v.Args[0])
if n == nil {
v.Fatalf("KeepLive with non-spilled value %s %s", v, v.Args[0])
}
if off != 0 {
v.Fatalf("KeepLive with non-zero offset spill location %s:%d", n, off)
}
gc.Gvarlive(n)
case ssa.Op386LoweredNilCheck:
// Optimization - if the subsequent block has a load or store
// at the same address, we don't need to issue this instruction.
mem := v.Args[1]
for _, w := range v.Block.Succs[0].Block().Values {
if w.Op == ssa.OpPhi {
if w.Type.IsMemory() {
mem = w
}
continue
}
if len(w.Args) == 0 || !w.Args[len(w.Args)-1].Type.IsMemory() {
// w doesn't use a store - can't be a memory op.
continue
}
if w.Args[len(w.Args)-1] != mem {
v.Fatalf("wrong store after nilcheck v=%s w=%s", v, w)
}
switch w.Op {
case ssa.Op386MOVLload, ssa.Op386MOVWload, ssa.Op386MOVBload,
ssa.Op386MOVLstore, ssa.Op386MOVWstore, ssa.Op386MOVBstore,
ssa.Op386MOVBLSXload, ssa.Op386MOVWLSXload,
ssa.Op386MOVSSload, ssa.Op386MOVSDload,
ssa.Op386MOVSSstore, ssa.Op386MOVSDstore:
if w.Args[0] == v.Args[0] && w.Aux == nil && w.AuxInt >= 0 && w.AuxInt < minZeroPage {
if gc.Debug_checknil != 0 && int(v.Line) > 1 {
gc.Warnl(v.Line, "removed nil check")
}
return
}
case ssa.Op386MOVLstoreconst, ssa.Op386MOVWstoreconst, ssa.Op386MOVBstoreconst:
off := ssa.ValAndOff(v.AuxInt).Off()
if w.Args[0] == v.Args[0] && w.Aux == nil && off >= 0 && off < minZeroPage {
if gc.Debug_checknil != 0 && int(v.Line) > 1 {
gc.Warnl(v.Line, "removed nil check")
}
return
}
}
if w.Type.IsMemory() {
if w.Op == ssa.OpVarDef || w.Op == ssa.OpVarKill || w.Op == ssa.OpVarLive {
// these ops are OK
mem = w
continue
}
// We can't delay the nil check past the next store.
break
}
}
// Issue a load which will fault if the input is nil.
// TODO: We currently use the 2-byte instruction TESTB AX, (reg).
// Should we use the 3-byte TESTB $0, (reg) instead? It is larger
// but it doesn't have false dependency on AX.
// Or maybe allocate an output register and use MOVL (reg),reg2 ?
// That trades clobbering flags for clobbering a register.
p := gc.Prog(x86.ATESTB)
p.From.Type = obj.TYPE_REG
p.From.Reg = x86.REG_AX
p.To.Type = obj.TYPE_MEM
p.To.Reg = gc.SSARegNum(v.Args[0])
gc.AddAux(&p.To, v)
if gc.Debug_checknil != 0 && v.Line > 1 { // v.Line==1 in generated wrappers
gc.Warnl(v.Line, "generated nil check")
}
default:
v.Unimplementedf("genValue not implemented: %s", v.LongString())
}
}
var blockJump = [...]struct {
asm, invasm obj.As
}{
ssa.Block386EQ: {x86.AJEQ, x86.AJNE},
ssa.Block386NE: {x86.AJNE, x86.AJEQ},
ssa.Block386LT: {x86.AJLT, x86.AJGE},
ssa.Block386GE: {x86.AJGE, x86.AJLT},
ssa.Block386LE: {x86.AJLE, x86.AJGT},
ssa.Block386GT: {x86.AJGT, x86.AJLE},
ssa.Block386ULT: {x86.AJCS, x86.AJCC},
ssa.Block386UGE: {x86.AJCC, x86.AJCS},
ssa.Block386UGT: {x86.AJHI, x86.AJLS},
ssa.Block386ULE: {x86.AJLS, x86.AJHI},
ssa.Block386ORD: {x86.AJPC, x86.AJPS},
ssa.Block386NAN: {x86.AJPS, x86.AJPC},
}
var eqfJumps = [2][2]gc.FloatingEQNEJump{
{{Jump: x86.AJNE, Index: 1}, {Jump: x86.AJPS, Index: 1}}, // next == b.Succs[0]
{{Jump: x86.AJNE, Index: 1}, {Jump: x86.AJPC, Index: 0}}, // next == b.Succs[1]
}
var nefJumps = [2][2]gc.FloatingEQNEJump{
{{Jump: x86.AJNE, Index: 0}, {Jump: x86.AJPC, Index: 1}}, // next == b.Succs[0]
{{Jump: x86.AJNE, Index: 0}, {Jump: x86.AJPS, Index: 0}}, // next == b.Succs[1]
}
func ssaGenBlock(s *gc.SSAGenState, b, next *ssa.Block) {
s.SetLineno(b.Line)
if gc.Thearch.Use387 {
// Empty the 387's FP stack before the block ends.
flush387(s)
}
switch b.Kind {
case ssa.BlockPlain, ssa.BlockCall, ssa.BlockCheck:
if b.Succs[0].Block() != next {
p := gc.Prog(obj.AJMP)
p.To.Type = obj.TYPE_BRANCH
s.Branches = append(s.Branches, gc.Branch{P: p, B: b.Succs[0].Block()})
}
case ssa.BlockDefer:
// defer returns in rax:
// 0 if we should continue executing
// 1 if we should jump to deferreturn call
p := gc.Prog(x86.ATESTL)
p.From.Type = obj.TYPE_REG
p.From.Reg = x86.REG_AX
p.To.Type = obj.TYPE_REG
p.To.Reg = x86.REG_AX
p = gc.Prog(x86.AJNE)
p.To.Type = obj.TYPE_BRANCH
s.Branches = append(s.Branches, gc.Branch{P: p, B: b.Succs[1].Block()})
if b.Succs[0].Block() != next {
p := gc.Prog(obj.AJMP)
p.To.Type = obj.TYPE_BRANCH
s.Branches = append(s.Branches, gc.Branch{P: p, B: b.Succs[0].Block()})
}
case ssa.BlockExit:
gc.Prog(obj.AUNDEF) // tell plive.go that we never reach here
case ssa.BlockRet:
gc.Prog(obj.ARET)
case ssa.BlockRetJmp:
p := gc.Prog(obj.AJMP)
p.To.Type = obj.TYPE_MEM
p.To.Name = obj.NAME_EXTERN
p.To.Sym = gc.Linksym(b.Aux.(*gc.Sym))
case ssa.Block386EQF:
gc.SSAGenFPJump(s, b, next, &eqfJumps)
case ssa.Block386NEF:
gc.SSAGenFPJump(s, b, next, &nefJumps)
case ssa.Block386EQ, ssa.Block386NE,
ssa.Block386LT, ssa.Block386GE,
ssa.Block386LE, ssa.Block386GT,
ssa.Block386ULT, ssa.Block386UGT,
ssa.Block386ULE, ssa.Block386UGE:
jmp := blockJump[b.Kind]
likely := b.Likely
var p *obj.Prog
switch next {
case b.Succs[0].Block():
p = gc.Prog(jmp.invasm)
likely *= -1
p.To.Type = obj.TYPE_BRANCH
s.Branches = append(s.Branches, gc.Branch{P: p, B: b.Succs[1].Block()})
case b.Succs[1].Block():
p = gc.Prog(jmp.asm)
p.To.Type = obj.TYPE_BRANCH
s.Branches = append(s.Branches, gc.Branch{P: p, B: b.Succs[0].Block()})
default:
p = gc.Prog(jmp.asm)
p.To.Type = obj.TYPE_BRANCH
s.Branches = append(s.Branches, gc.Branch{P: p, B: b.Succs[0].Block()})
q := gc.Prog(obj.AJMP)
q.To.Type = obj.TYPE_BRANCH
s.Branches = append(s.Branches, gc.Branch{P: q, B: b.Succs[1].Block()})
}
// liblink reorders the instruction stream as it sees fit.
// Pass along what we know so liblink can make use of it.
// TODO: Once we've fully switched to SSA,
// make liblink leave our output alone.
switch likely {
case ssa.BranchUnlikely:
p.From.Type = obj.TYPE_CONST
p.From.Offset = 0
case ssa.BranchLikely:
p.From.Type = obj.TYPE_CONST
p.From.Offset = 1
}
default:
b.Unimplementedf("branch not implemented: %s. Control: %s", b.LongString(), b.Control.LongString())
}
}
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