From 2e60c00f56cdab9bb02e649e089b2ee5761acf26 Mon Sep 17 00:00:00 2001 From: Cherry Zhang Date: Thu, 4 Feb 2021 11:43:24 -0500 Subject: [PATCH] [dev.regabi] cmd/internal/obj/x86: use g register in stack bounds check 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 Run-TryBot: Cherry Zhang TryBot-Result: Go Bot Reviewed-by: David Chase --- src/cmd/internal/obj/x86/obj6.go | 29 +++++++++++++++++++---------- 1 file changed, 19 insertions(+), 10 deletions(-) diff --git a/src/cmd/internal/obj/x86/obj6.go b/src/cmd/internal/obj/x86/obj6.go index 1674db626f..84de58a4c4 100644 --- a/src/cmd/internal/obj/x86/obj6.go +++ b/src/cmd/internal/obj/x86/obj6.go @@ -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 -- 2.50.0