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[dev.regabi] cmd/internal/obj/x86: use g register in stack bounds check

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In ABIInternal context, we can directly use the g register for
stack bounds check.

Change-Id: I8b1073a3343984a6cd76cf5734ddc4a8cd5dc73f
Reviewed-on: https://go-review.googlesource.com/c/go/+/289711
Trust: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
This commit is contained in:
Cherry Zhang 2021-02-04 11:43:24 -05:00
parent 22f9e1ccbc
commit 2e60c00f56
1 changed files with 19 additions and 10 deletions
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29
src/cmd/internal/obj/x86/obj6.go
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@ -637,13 +637,19 @@ func preprocess(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) {
}
}
var regg int16
if !p.From.Sym.NoSplit() || (p.From.Sym.Wrapper() && !p.From.Sym.ABIWrapper()) {
p = obj.Appendp(p, newprog)
p = load_g_cx(ctxt, p, newprog) // load g into CX
if ctxt.Arch.Family == sys.AMD64 && objabi.Regabi_enabled != 0 && cursym.ABI() == obj.ABIInternal {
regg = REGG // use the g register directly in ABIInternal
} else {
p = obj.Appendp(p, newprog)
p = load_g_cx(ctxt, p, newprog) // load g into CX
regg = REG_CX
}
}
if !cursym.Func().Text.From.Sym.NoSplit() {
p = stacksplit(ctxt, cursym, p, newprog, autoffset, int32(textarg)) // emit split check
p = stacksplit(ctxt, cursym, p, newprog, autoffset, int32(textarg), regg) // emit split check
}
// Delve debugger would like the next instruction to be noted as the end of the function prologue.
@ -695,7 +701,7 @@ func preprocess(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) {
// g._panic.argp = bottom-of-frame
// }
//
// MOVQ g_panic(CX), BX
// MOVQ g_panic(g), BX
// TESTQ BX, BX
// JNE checkargp
// end:
@ -718,7 +724,7 @@ func preprocess(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) {
p = obj.Appendp(p, newprog)
p.As = AMOVQ
p.From.Type = obj.TYPE_MEM
p.From.Reg = REG_CX
p.From.Reg = regg
p.From.Offset = 4 * int64(ctxt.Arch.PtrSize) // g_panic
p.To.Type = obj.TYPE_REG
p.To.Reg = REG_BX
@ -969,9 +975,9 @@ func load_g_cx(ctxt *obj.Link, p *obj.Prog, newprog obj.ProgAlloc) *obj.Prog {
// Append code to p to check for stack split.
// Appends to (does not overwrite) p.
// Assumes g is in CX.
// Assumes g is in rg.
// Returns last new instruction.
func stacksplit(ctxt *obj.Link, cursym *obj.LSym, p *obj.Prog, newprog obj.ProgAlloc, framesize int32, textarg int32) *obj.Prog {
func stacksplit(ctxt *obj.Link, cursym *obj.LSym, p *obj.Prog, newprog obj.ProgAlloc, framesize int32, textarg int32, rg int16) *obj.Prog {
cmp := ACMPQ
lea := ALEAQ
mov := AMOVQ
@ -993,7 +999,8 @@ func stacksplit(ctxt *obj.Link, cursym *obj.LSym, p *obj.Prog, newprog obj.ProgA
p.As = cmp
p.From.Type = obj.TYPE_REG
p.From.Reg = REG_SP
indir_cx(ctxt, &p.To)
p.To.Type = obj.TYPE_MEM
p.To.Reg = rg
p.To.Offset = 2 * int64(ctxt.Arch.PtrSize) // G.stackguard0
if cursym.CFunc() {
p.To.Offset = 3 * int64(ctxt.Arch.PtrSize) // G.stackguard1
@ -1021,7 +1028,8 @@ func stacksplit(ctxt *obj.Link, cursym *obj.LSym, p *obj.Prog, newprog obj.ProgA
p.As = cmp
p.From.Type = obj.TYPE_REG
p.From.Reg = REG_AX
indir_cx(ctxt, &p.To)
p.To.Type = obj.TYPE_MEM
p.To.Reg = rg
p.To.Offset = 2 * int64(ctxt.Arch.PtrSize) // G.stackguard0
if cursym.CFunc() {
p.To.Offset = 3 * int64(ctxt.Arch.PtrSize) // G.stackguard1
@ -1047,7 +1055,8 @@ func stacksplit(ctxt *obj.Link, cursym *obj.LSym, p *obj.Prog, newprog obj.ProgA
p = obj.Appendp(p, newprog)
p.As = mov
indir_cx(ctxt, &p.From)
p.From.Type = obj.TYPE_MEM
p.From.Reg = rg
p.From.Offset = 2 * int64(ctxt.Arch.PtrSize) // G.stackguard0
if cursym.CFunc() {
p.From.Offset = 3 * int64(ctxt.Arch.PtrSize) // G.stackguard1