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synced 2025-12-08 06:10:04 +00:00
runtime: enable framepointer on all arm64
Frame pointers were already enabled on linux, darwin, ios, but not freebsd, android, openbsd, netbsd. But the space was reserved on all platforms, leading to two different arm64 framepointer conditions in different parts of the code, one of which had no name (framepointer_enabled || GOARCH == "arm64", which might have been "framepointer_space_reserved"). So on the disabled systems, the stack layouts were still set up for frame pointers and the only difference was not actually maintaining the FP register in the generated code. Reduce complexity by just enabling the frame pointer completely on all the arm64 systems. This commit passes on freebsd, android, netbsd. I have not been able to try it on openbsd. This CL is part of a stack adding windows/arm64 support (#36439), intended to land in the Go 1.17 cycle. This CL is, however, not windows/arm64-specific. It is cleanup meant to make the port (and future ports) easier. Change-Id: I83bd23369d24b76db4c6a648fa74f6917819a093 Reviewed-on: https://go-review.googlesource.com/c/go/+/288814 Trust: Russ Cox <rsc@golang.org> Reviewed-by: Cherry Zhang <cherryyz@google.com>
This commit is contained in:
Russ Cox
parent
b19e7b518e
commit
09e059afb1
7 changed files with 164 additions and 136 deletions
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@ -271,8 +271,7 @@ func createSimpleVar(fnsym *obj.LSym, n *ir.Name) *dwarf.Var {
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if base.Ctxt.FixedFrameSize() == 0 {
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if base.Ctxt.FixedFrameSize() == 0 {
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offs -= int64(types.PtrSize)
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offs -= int64(types.PtrSize)
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}
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}
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if objabi.Framepointer_enabled || objabi.GOARCH == "arm64" {
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if objabi.Framepointer_enabled {
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// There is a word space for FP on ARM64 even if the frame pointer is disabled
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offs -= int64(types.PtrSize)
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offs -= int64(types.PtrSize)
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}
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}
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@ -213,8 +213,7 @@ func StackOffset(slot ssa.LocalSlot) int32 {
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if base.Ctxt.FixedFrameSize() == 0 {
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if base.Ctxt.FixedFrameSize() == 0 {
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off -= int64(types.PtrSize)
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off -= int64(types.PtrSize)
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}
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}
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if objabi.Framepointer_enabled || objabi.GOARCH == "arm64" {
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if objabi.Framepointer_enabled {
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// There is a word space for FP on ARM64 even if the frame pointer is disabled
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off -= int64(types.PtrSize)
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off -= int64(types.PtrSize)
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}
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}
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case ir.PPARAM, ir.PPARAMOUT:
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case ir.PPARAM, ir.PPARAMOUT:
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@ -239,7 +239,7 @@ const (
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REGCTXT = REG_R26 // environment for closures
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REGCTXT = REG_R26 // environment for closures
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REGTMP = REG_R27 // reserved for liblink
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REGTMP = REG_R27 // reserved for liblink
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REGG = REG_R28 // G
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REGG = REG_R28 // G
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REGFP = REG_R29 // frame pointer, unused in the Go toolchain
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REGFP = REG_R29 // frame pointer
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REGLINK = REG_R30
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REGLINK = REG_R30
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// ARM64 uses R31 as both stack pointer and zero register,
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// ARM64 uses R31 as both stack pointer and zero register,
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@ -622,25 +622,24 @@ func preprocess(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) {
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prologueEnd.Pos = prologueEnd.Pos.WithXlogue(src.PosPrologueEnd)
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prologueEnd.Pos = prologueEnd.Pos.WithXlogue(src.PosPrologueEnd)
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if objabi.Framepointer_enabled {
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// Frame pointer.
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q1 = obj.Appendp(q1, c.newprog)
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q1 = obj.Appendp(q1, c.newprog)
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q1.Pos = p.Pos
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q1.Pos = p.Pos
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q1.As = AMOVD
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q1.As = AMOVD
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q1.From.Type = obj.TYPE_REG
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q1.From.Type = obj.TYPE_REG
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q1.From.Reg = REGFP
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q1.From.Reg = REGFP
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q1.To.Type = obj.TYPE_MEM
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q1.To.Type = obj.TYPE_MEM
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q1.To.Reg = REGSP
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q1.To.Reg = REGSP
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q1.To.Offset = -8
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q1.To.Offset = -8
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q1 = obj.Appendp(q1, c.newprog)
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q1 = obj.Appendp(q1, c.newprog)
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q1.Pos = p.Pos
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q1.Pos = p.Pos
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q1.As = ASUB
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q1.As = ASUB
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q1.From.Type = obj.TYPE_CONST
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q1.From.Type = obj.TYPE_CONST
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q1.From.Offset = 8
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q1.From.Offset = 8
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q1.Reg = REGSP
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q1.Reg = REGSP
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q1.To.Type = obj.TYPE_REG
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q1.To.Type = obj.TYPE_REG
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q1.To.Reg = REGFP
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q1.To.Reg = REGFP
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}
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if c.cursym.Func().Text.From.Sym.Wrapper() {
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if c.cursym.Func().Text.From.Sym.Wrapper() {
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// if(g->panic != nil && g->panic->argp == FP) g->panic->argp = bottom-of-frame
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// if(g->panic != nil && g->panic->argp == FP) g->panic->argp = bottom-of-frame
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@ -765,28 +764,26 @@ func preprocess(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) {
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p.To.Reg = REGSP
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p.To.Reg = REGSP
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p.Spadj = -c.autosize
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p.Spadj = -c.autosize
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if objabi.Framepointer_enabled {
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// Frame pointer.
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p = obj.Appendp(p, c.newprog)
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p = obj.Appendp(p, c.newprog)
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p.As = ASUB
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p.As = ASUB
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p.From.Type = obj.TYPE_CONST
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p.From.Type = obj.TYPE_CONST
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p.From.Offset = 8
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p.From.Offset = 8
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p.Reg = REGSP
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p.Reg = REGSP
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p.To.Type = obj.TYPE_REG
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p.To.Type = obj.TYPE_REG
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p.To.Reg = REGFP
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p.To.Reg = REGFP
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}
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}
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}
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} else {
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} else {
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/* want write-back pre-indexed SP+autosize -> SP, loading REGLINK*/
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/* want write-back pre-indexed SP+autosize -> SP, loading REGLINK*/
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if objabi.Framepointer_enabled {
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// Frame pointer.
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p.As = AMOVD
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p.As = AMOVD
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p.From.Type = obj.TYPE_MEM
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p.From.Type = obj.TYPE_MEM
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p.From.Reg = REGSP
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p.From.Reg = REGSP
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p.From.Offset = -8
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p.From.Offset = -8
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p.To.Type = obj.TYPE_REG
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p.To.Type = obj.TYPE_REG
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p.To.Reg = REGFP
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p.To.Reg = REGFP
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p = obj.Appendp(p, c.newprog)
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p = obj.Appendp(p, c.newprog)
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}
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aoffset := c.autosize
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aoffset := c.autosize
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@ -821,6 +818,28 @@ func preprocess(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) {
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}
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}
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}
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}
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// If enabled, this code emits 'MOV PC, R27' before every 'MOV LR, PC',
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// so that if you are debugging a low-level crash where PC and LR are zero,
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// you can look at R27 to see what jumped to the zero.
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// This is useful when bringing up Go on a new system.
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// (There is similar code in ../ppc64/obj9.go:/if.false.)
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const debugRETZERO = false
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if debugRETZERO {
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if p.As != obj.ARET {
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q = newprog()
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q.Pos = p.Pos
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q.Link = p.Link
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p.Link = q
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p = q
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}
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p.As = AADR
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p.From.Type = obj.TYPE_BRANCH
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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 = REGTMP
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}
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if p.As != obj.ARET {
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if p.As != obj.ARET {
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q = newprog()
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q = newprog()
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q.Pos = p.Pos
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q.Pos = p.Pos
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@ -866,110 +885,106 @@ func preprocess(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) {
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}
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}
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case obj.ADUFFCOPY:
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case obj.ADUFFCOPY:
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if objabi.Framepointer_enabled {
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// ADR ret_addr, R27
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// ADR ret_addr, R27
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// STP (FP, R27), -24(SP)
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// STP (FP, R27), -24(SP)
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// SUB 24, SP, FP
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// SUB 24, SP, FP
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// DUFFCOPY
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// DUFFCOPY
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// ret_addr:
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// ret_addr:
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// SUB 8, SP, FP
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// SUB 8, SP, FP
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q1 := p
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q1 := p
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// copy DUFFCOPY from q1 to q4
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// copy DUFFCOPY from q1 to q4
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q4 := obj.Appendp(p, c.newprog)
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q4 := obj.Appendp(p, c.newprog)
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q4.Pos = p.Pos
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q4.Pos = p.Pos
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q4.As = obj.ADUFFCOPY
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q4.As = obj.ADUFFCOPY
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q4.To = p.To
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q4.To = p.To
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q1.As = AADR
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q1.As = AADR
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q1.From.Type = obj.TYPE_BRANCH
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q1.From.Type = obj.TYPE_BRANCH
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q1.To.Type = obj.TYPE_REG
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q1.To.Type = obj.TYPE_REG
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q1.To.Reg = REG_R27
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q1.To.Reg = REG_R27
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q2 := obj.Appendp(q1, c.newprog)
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q2 := obj.Appendp(q1, c.newprog)
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q2.Pos = p.Pos
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q2.Pos = p.Pos
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q2.As = ASTP
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q2.As = ASTP
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q2.From.Type = obj.TYPE_REGREG
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q2.From.Type = obj.TYPE_REGREG
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q2.From.Reg = REGFP
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q2.From.Reg = REGFP
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q2.From.Offset = int64(REG_R27)
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q2.From.Offset = int64(REG_R27)
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q2.To.Type = obj.TYPE_MEM
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q2.To.Type = obj.TYPE_MEM
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q2.To.Reg = REGSP
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q2.To.Reg = REGSP
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q2.To.Offset = -24
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q2.To.Offset = -24
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// maintaine FP for DUFFCOPY
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// maintain FP for DUFFCOPY
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q3 := obj.Appendp(q2, c.newprog)
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q3 := obj.Appendp(q2, c.newprog)
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q3.Pos = p.Pos
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q3.Pos = p.Pos
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q3.As = ASUB
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q3.As = ASUB
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q3.From.Type = obj.TYPE_CONST
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q3.From.Type = obj.TYPE_CONST
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q3.From.Offset = 24
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q3.From.Offset = 24
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q3.Reg = REGSP
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q3.Reg = REGSP
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q3.To.Type = obj.TYPE_REG
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q3.To.Type = obj.TYPE_REG
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q3.To.Reg = REGFP
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q3.To.Reg = REGFP
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q5 := obj.Appendp(q4, c.newprog)
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q5 := obj.Appendp(q4, c.newprog)
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q5.Pos = p.Pos
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q5.Pos = p.Pos
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q5.As = ASUB
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q5.As = ASUB
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q5.From.Type = obj.TYPE_CONST
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q5.From.Type = obj.TYPE_CONST
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q5.From.Offset = 8
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q5.From.Offset = 8
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q5.Reg = REGSP
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q5.Reg = REGSP
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q5.To.Type = obj.TYPE_REG
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q5.To.Type = obj.TYPE_REG
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q5.To.Reg = REGFP
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q5.To.Reg = REGFP
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q1.From.SetTarget(q5)
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q1.From.SetTarget(q5)
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p = q5
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p = q5
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}
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case obj.ADUFFZERO:
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case obj.ADUFFZERO:
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if objabi.Framepointer_enabled {
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// ADR ret_addr, R27
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// ADR ret_addr, R27
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// STP (FP, R27), -24(SP)
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// STP (FP, R27), -24(SP)
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// SUB 24, SP, FP
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// SUB 24, SP, FP
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// DUFFZERO
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// DUFFZERO
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// ret_addr:
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// ret_addr:
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// SUB 8, SP, FP
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// SUB 8, SP, FP
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q1 := p
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q1 := p
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// copy DUFFZERO from q1 to q4
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// copy DUFFZERO from q1 to q4
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q4 := obj.Appendp(p, c.newprog)
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q4 := obj.Appendp(p, c.newprog)
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q4.Pos = p.Pos
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q4.Pos = p.Pos
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q4.As = obj.ADUFFZERO
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q4.As = obj.ADUFFZERO
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q4.To = p.To
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q4.To = p.To
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q1.As = AADR
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q1.As = AADR
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q1.From.Type = obj.TYPE_BRANCH
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q1.From.Type = obj.TYPE_BRANCH
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q1.To.Type = obj.TYPE_REG
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q1.To.Type = obj.TYPE_REG
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q1.To.Reg = REG_R27
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q1.To.Reg = REG_R27
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q2 := obj.Appendp(q1, c.newprog)
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q2 := obj.Appendp(q1, c.newprog)
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q2.Pos = p.Pos
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q2.Pos = p.Pos
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q2.As = ASTP
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q2.As = ASTP
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q2.From.Type = obj.TYPE_REGREG
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q2.From.Type = obj.TYPE_REGREG
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q2.From.Reg = REGFP
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q2.From.Reg = REGFP
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q2.From.Offset = int64(REG_R27)
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q2.From.Offset = int64(REG_R27)
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q2.To.Type = obj.TYPE_MEM
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q2.To.Type = obj.TYPE_MEM
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q2.To.Reg = REGSP
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q2.To.Reg = REGSP
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q2.To.Offset = -24
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q2.To.Offset = -24
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// maintaine FP for DUFFZERO
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// maintain FP for DUFFZERO
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q3 := obj.Appendp(q2, c.newprog)
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q3 := obj.Appendp(q2, c.newprog)
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q3.Pos = p.Pos
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q3.Pos = p.Pos
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q3.As = ASUB
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q3.As = ASUB
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q3.From.Type = obj.TYPE_CONST
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q3.From.Type = obj.TYPE_CONST
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q3.From.Offset = 24
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q3.From.Offset = 24
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q3.Reg = REGSP
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q3.Reg = REGSP
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q3.To.Type = obj.TYPE_REG
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q3.To.Type = obj.TYPE_REG
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q3.To.Reg = REGFP
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q3.To.Reg = REGFP
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q5 := obj.Appendp(q4, c.newprog)
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q5 := obj.Appendp(q4, c.newprog)
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q5.Pos = p.Pos
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q5.Pos = p.Pos
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q5.As = ASUB
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q5.As = ASUB
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q5.From.Type = obj.TYPE_CONST
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q5.From.Type = obj.TYPE_CONST
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q5.From.Offset = 8
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q5.From.Offset = 8
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q5.Reg = REGSP
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q5.Reg = REGSP
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q5.To.Type = obj.TYPE_REG
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q5.To.Type = obj.TYPE_REG
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q5.To.Reg = REGFP
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q5.To.Reg = REGFP
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q1.From.SetTarget(q5)
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q1.From.SetTarget(q5)
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p = q5
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p = q5
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}
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}
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}
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if p.To.Type == obj.TYPE_REG && p.To.Reg == REGSP && p.Spadj == 0 {
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if p.To.Type == obj.TYPE_REG && p.To.Reg == REGSP && p.Spadj == 0 {
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@ -137,7 +137,7 @@ func init() {
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}
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}
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// Note: must agree with runtime.framepointer_enabled.
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// Note: must agree with runtime.framepointer_enabled.
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var Framepointer_enabled = GOARCH == "amd64" || GOARCH == "arm64" && (GOOS == "linux" || GOOS == "darwin" || GOOS == "ios")
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var Framepointer_enabled = GOARCH == "amd64" || GOARCH == "arm64"
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func addexp(s string) {
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func addexp(s string) {
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// Could do general integer parsing here, but the runtime copy doesn't yet.
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// Could do general integer parsing here, but the runtime copy doesn't yet.
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@ -1106,4 +1106,4 @@ var (
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)
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)
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// Must agree with cmd/internal/objabi.Framepointer_enabled.
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// Must agree with cmd/internal/objabi.Framepointer_enabled.
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const framepointer_enabled = GOARCH == "amd64" || GOARCH == "arm64" && (GOOS == "linux" || GOOS == "darwin" || GOOS == "ios")
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const framepointer_enabled = GOARCH == "amd64" || GOARCH == "arm64"
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@ -275,7 +275,22 @@ func gentraceback(pc0, sp0, lr0 uintptr, gp *g, skip int, pcbuf *uintptr, max in
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// For architectures with frame pointers, if there's
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// For architectures with frame pointers, if there's
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// a frame, then there's a saved frame pointer here.
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// a frame, then there's a saved frame pointer here.
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if frame.varp > frame.sp && (GOARCH == "amd64" || GOARCH == "arm64") {
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//
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// NOTE: This code is not as general as it looks.
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// On x86, the ABI is to save the frame pointer word at the
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// top of the stack frame, so we have to back down over it.
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// On arm64, the frame pointer should be at the bottom of
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// the stack (with R29 (aka FP) = RSP), in which case we would
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// not want to do the subtraction here. But we started out without
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// any frame pointer, and when we wanted to add it, we didn't
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// want to break all the assembly doing direct writes to 8(RSP)
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// to set the first parameter to a called function.
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// So we decided to write the FP link *below* the stack pointer
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// (with R29 = RSP - 8 in Go functions).
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// This is technically ABI-compatible but not standard.
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||||||
|
// And it happens to end up mimicking the x86 layout.
|
||||||
|
// Other architectures may make different decisions.
|
||||||
|
if frame.varp > frame.sp && framepointer_enabled {
|
||||||
frame.varp -= sys.PtrSize
|
frame.varp -= sys.PtrSize
|
||||||
}
|
}
|
||||||
|
|
||||||
|
|
|
||||||
Loading…
Add table
Add a link
Reference in a new issue