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cmd/compile: register abi, morestack work and mole whacking
Morestack works for non-pointer register parameters Within a function body, pointer-typed parameters are correctly tracked. Results still not hooked up. For #40724. Change-Id: Icaee0b51d0da54af983662d945d939b756088746 Reviewed-on: https://go-review.googlesource.com/c/go/+/294410 Trust: David Chase <drchase@google.com> Reviewed-by: Cherry Zhang <cherryyz@google.com>
This commit is contained in:
David Chase
parent
868a110c56
commit
a2d92b5143
11 changed files with 175 additions and 57 deletions
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@ -135,7 +135,7 @@ func progedit(ctxt *obj.Link, p *obj.Prog, newprog obj.ProgAlloc) {
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p.To.Index = REG_NONE
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}
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} else {
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// load_g_cx, below, always inserts the 1-instruction sequence. Rewrite it
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// load_g, below, always inserts the 1-instruction sequence. Rewrite it
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// as the 2-instruction sequence if necessary.
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// MOVQ 0(TLS), BX
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// becomes
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@ -644,8 +644,12 @@ func preprocess(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) {
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regg = REGG // use the g register directly in ABIInternal
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} else {
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p = obj.Appendp(p, newprog)
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p = load_g_cx(ctxt, p, newprog) // load g into CX
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regg = REG_CX
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if ctxt.Arch.Family == sys.AMD64 {
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// Using this register means that stacksplit works w/ //go:registerparams even when objabi.Regabi_enabled == 0
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regg = REGG // == REG_R14
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}
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p = load_g(ctxt, p, newprog, regg) // load g into regg
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}
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}
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@ -963,7 +967,7 @@ func indir_cx(ctxt *obj.Link, a *obj.Addr) {
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// Overwriting p is unusual but it lets use this in both the
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// prologue (caller must call appendp first) and in the epilogue.
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// Returns last new instruction.
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func load_g_cx(ctxt *obj.Link, p *obj.Prog, newprog obj.ProgAlloc) *obj.Prog {
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func load_g(ctxt *obj.Link, p *obj.Prog, newprog obj.ProgAlloc, rg int16) *obj.Prog {
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p.As = AMOVQ
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if ctxt.Arch.PtrSize == 4 {
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p.As = AMOVL
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@ -972,7 +976,7 @@ func load_g_cx(ctxt *obj.Link, p *obj.Prog, newprog obj.ProgAlloc) *obj.Prog {
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p.From.Reg = REG_TLS
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p.From.Offset = 0
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p.To.Type = obj.TYPE_REG
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p.To.Reg = REG_CX
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p.To.Reg = rg
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next := p.Link
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progedit(ctxt, p, newprog)
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@ -1027,9 +1031,14 @@ func stacksplit(ctxt *obj.Link, cursym *obj.LSym, p *obj.Prog, newprog obj.ProgA
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// unnecessarily. See issue #35470.
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p = ctxt.StartUnsafePoint(p, newprog)
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} else if framesize <= objabi.StackBig {
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tmp := int16(REG_AX) // use AX for 32-bit
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if ctxt.Arch.Family == sys.AMD64 {
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// for 64-bit, stay away from register ABI parameter registers, even w/o GOEXPERIMENT=regabi
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tmp = int16(REG_R13)
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}
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// large stack: SP-framesize <= stackguard-StackSmall
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// LEAQ -xxx(SP), AX
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// CMPQ AX, stackguard
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// LEAQ -xxx(SP), tmp
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// CMPQ tmp, stackguard
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p = obj.Appendp(p, newprog)
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p.As = lea
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@ -1037,12 +1046,12 @@ func stacksplit(ctxt *obj.Link, cursym *obj.LSym, p *obj.Prog, newprog obj.ProgA
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p.From.Reg = REG_SP
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p.From.Offset = -(int64(framesize) - objabi.StackSmall)
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p.To.Type = obj.TYPE_REG
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p.To.Reg = REG_AX
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p.To.Reg = tmp
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p = obj.Appendp(p, newprog)
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p.As = cmp
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p.From.Type = obj.TYPE_REG
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p.From.Reg = REG_AX
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p.From.Reg = tmp
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p.To.Type = obj.TYPE_MEM
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p.To.Reg = rg
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p.To.Offset = 2 * int64(ctxt.Arch.PtrSize) // G.stackguard0
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@ -1052,6 +1061,12 @@ func stacksplit(ctxt *obj.Link, cursym *obj.LSym, p *obj.Prog, newprog obj.ProgA
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p = ctxt.StartUnsafePoint(p, newprog) // see the comment above
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} else {
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tmp1 := int16(REG_SI)
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tmp2 := int16(REG_AX)
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if ctxt.Arch.Family == sys.AMD64 {
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tmp1 = int16(REG_R13) // register ABI uses REG_SI and REG_AX for parameters.
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tmp2 = int16(REG_R12)
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}
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// Such a large stack we need to protect against wraparound.
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// If SP is close to zero:
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// SP-stackguard+StackGuard <= framesize + (StackGuard-StackSmall)
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@ -1060,12 +1075,12 @@ func stacksplit(ctxt *obj.Link, cursym *obj.LSym, p *obj.Prog, newprog obj.ProgA
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//
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// Preemption sets stackguard to StackPreempt, a very large value.
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// That breaks the math above, so we have to check for that explicitly.
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// MOVQ stackguard, SI
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// MOVQ stackguard, tmp1
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// CMPQ SI, $StackPreempt
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// JEQ label-of-call-to-morestack
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// LEAQ StackGuard(SP), AX
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// SUBQ SI, AX
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// CMPQ AX, $(framesize+(StackGuard-StackSmall))
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// LEAQ StackGuard(SP), tmp2
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// SUBQ tmp1, tmp2
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// CMPQ tmp2, $(framesize+(StackGuard-StackSmall))
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p = obj.Appendp(p, newprog)
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@ -1077,14 +1092,14 @@ func stacksplit(ctxt *obj.Link, cursym *obj.LSym, p *obj.Prog, newprog obj.ProgA
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p.From.Offset = 3 * int64(ctxt.Arch.PtrSize) // G.stackguard1
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}
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p.To.Type = obj.TYPE_REG
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p.To.Reg = REG_SI
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p.To.Reg = tmp1
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p = ctxt.StartUnsafePoint(p, newprog) // see the comment above
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p = obj.Appendp(p, newprog)
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p.As = cmp
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p.From.Type = obj.TYPE_REG
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p.From.Reg = REG_SI
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p.From.Reg = tmp1
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p.To.Type = obj.TYPE_CONST
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p.To.Offset = objabi.StackPreempt
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if ctxt.Arch.Family == sys.I386 {
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@ -1102,19 +1117,19 @@ func stacksplit(ctxt *obj.Link, cursym *obj.LSym, p *obj.Prog, newprog obj.ProgA
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p.From.Reg = REG_SP
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p.From.Offset = int64(objabi.StackGuard)
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p.To.Type = obj.TYPE_REG
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p.To.Reg = REG_AX
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p.To.Reg = tmp2
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p = obj.Appendp(p, newprog)
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p.As = sub
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p.From.Type = obj.TYPE_REG
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p.From.Reg = REG_SI
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p.From.Reg = tmp1
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p.To.Type = obj.TYPE_REG
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p.To.Reg = REG_AX
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p.To.Reg = tmp2
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p = obj.Appendp(p, newprog)
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p.As = cmp
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p.From.Type = obj.TYPE_REG
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p.From.Reg = REG_AX
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p.From.Reg = tmp2
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p.To.Type = obj.TYPE_CONST
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p.To.Offset = int64(framesize) + (int64(objabi.StackGuard) - objabi.StackSmall)
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}
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@ -1139,7 +1154,7 @@ func stacksplit(ctxt *obj.Link, cursym *obj.LSym, p *obj.Prog, newprog obj.ProgA
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pcdata := ctxt.EmitEntryStackMap(cursym, spfix, newprog)
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spill := ctxt.StartUnsafePoint(pcdata, newprog)
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pcdata = ctxt.SpillRegisterArgs(spill, newprog)
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pcdata = cursym.Func().SpillRegisterArgs(spill, newprog)
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call := obj.Appendp(pcdata, newprog)
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call.Pos = cursym.Func().Text.Pos
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@ -1164,7 +1179,7 @@ func stacksplit(ctxt *obj.Link, cursym *obj.LSym, p *obj.Prog, newprog obj.ProgA
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progedit(ctxt, callend.Link, newprog)
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}
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pcdata = ctxt.UnspillRegisterArgs(callend, newprog)
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pcdata = cursym.Func().UnspillRegisterArgs(callend, newprog)
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pcdata = ctxt.EndUnsafePoint(pcdata, newprog, -1)
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jmp := obj.Appendp(pcdata, newprog)
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