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runtime: framepointers are no longer an experiment - hard code them

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I think they are no longer experimental status. Might as well promote
them to permanent.

Change-Id: Id1259601b3dd2061dd60df86ee48080bfb575d2f
Reviewed-on: https://go-review.googlesource.com/c/go/+/249857
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
This commit is contained in:
Keith Randall 2020-08-21 11:09:45 -07:00
parent 29634436fd
commit 5c2c6d3fbf
14 changed files with 28 additions and 51 deletions
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4
src/cmd/compile/internal/gc/pgen.go
View File

@ -507,7 +507,7 @@ func createSimpleVar(fnsym *obj.LSym, n *Node) *dwarf.Var {
if Ctxt.FixedFrameSize() == 0 {
offs -= int64(Widthptr)
}
if objabi.Framepointer_enabled(objabi.GOOS, objabi.GOARCH) || objabi.GOARCH == "arm64" {
if objabi.Framepointer_enabled || objabi.GOARCH == "arm64" {
// There is a word space for FP on ARM64 even if the frame pointer is disabled
offs -= int64(Widthptr)
}
@ -703,7 +703,7 @@ func stackOffset(slot ssa.LocalSlot) int32 {
if Ctxt.FixedFrameSize() == 0 {
base -= int64(Widthptr)
}
if objabi.Framepointer_enabled(objabi.GOOS, objabi.GOARCH) || objabi.GOARCH == "arm64" {
if objabi.Framepointer_enabled || objabi.GOARCH == "arm64" {
// There is a word space for FP on ARM64 even if the frame pointer is disabled
base -= int64(Widthptr)
}

2
src/cmd/compile/internal/ssa/regalloc.go
View File

@ -588,7 +588,7 @@ func (s *regAllocState) init(f *Func) {
if s.f.Config.hasGReg {
s.allocatable &^= 1 << s.GReg
}
if s.f.Config.ctxt.Framepointer_enabled && s.f.Config.FPReg >= 0 {
if objabi.Framepointer_enabled && s.f.Config.FPReg >= 0 {
s.allocatable &^= 1 << uint(s.f.Config.FPReg)
}
if s.f.Config.LinkReg != -1 {

10
src/cmd/internal/obj/arm64/obj7.go
View File

@ -621,7 +621,7 @@ func preprocess(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) {
prologueEnd.Pos = prologueEnd.Pos.WithXlogue(src.PosPrologueEnd)
if objabi.Framepointer_enabled(objabi.GOOS, objabi.GOARCH) {
if objabi.Framepointer_enabled {
q1 = obj.Appendp(q1, c.newprog)
q1.Pos = p.Pos
q1.As = AMOVD
@ -764,7 +764,7 @@ func preprocess(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) {
p.To.Reg = REGSP
p.Spadj = -c.autosize
if objabi.Framepointer_enabled(objabi.GOOS, objabi.GOARCH) {
if objabi.Framepointer_enabled {
p = obj.Appendp(p, c.newprog)
p.As = ASUB
p.From.Type = obj.TYPE_CONST
@ -777,7 +777,7 @@ func preprocess(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) {
} else {
/* want write-back pre-indexed SP+autosize -> SP, loading REGLINK*/
if objabi.Framepointer_enabled(objabi.GOOS, objabi.GOARCH) {
if objabi.Framepointer_enabled {
p.As = AMOVD
p.From.Type = obj.TYPE_MEM
p.From.Reg = REGSP
@ -865,7 +865,7 @@ func preprocess(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) {
}
case obj.ADUFFCOPY:
if objabi.Framepointer_enabled(objabi.GOOS, objabi.GOARCH) {
if objabi.Framepointer_enabled {
// ADR ret_addr, R27
// STP (FP, R27), -24(SP)
// SUB 24, SP, FP
@ -918,7 +918,7 @@ func preprocess(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) {
}
case obj.ADUFFZERO:
if objabi.Framepointer_enabled(objabi.GOOS, objabi.GOARCH) {
if objabi.Framepointer_enabled {
// ADR ret_addr, R27
// STP (FP, R27), -24(SP)
// SUB 24, SP, FP

1
src/cmd/internal/obj/link.go
View File

@ -683,7 +683,6 @@ type Link struct {
Errors int
InParallel bool // parallel backend phase in effect
Framepointer_enabled bool
UseBASEntries bool // use Base Address Selection Entries in location lists and PC ranges
IsAsm bool // is the source assembly language, which may contain surprising idioms (e.g., call tables)

1
src/cmd/internal/obj/sym.go
View File

@ -53,7 +53,6 @@ func Linknew(arch *LinkArch) *Link {
}
ctxt.Flag_optimize = true
ctxt.Framepointer_enabled = objabi.Framepointer_enabled(objabi.GOOS, arch.Name)
return ctxt
}

6
src/cmd/internal/obj/x86/asm6.go
View File

@ -4833,12 +4833,12 @@ func (ab *AsmBuf) doasm(ctxt *obj.Link, cursym *obj.LSym, p *obj.Prog) {
ctxt.Diag("directly calling duff when dynamically linking Go")
}
if ctxt.Framepointer_enabled && yt.zcase == Zcallduff && ctxt.Arch.Family == sys.AMD64 {
if yt.zcase == Zcallduff && ctxt.Arch.Family == sys.AMD64 {
// Maintain BP around call, since duffcopy/duffzero can't do it
// (the call jumps into the middle of the function).
// This makes it possible to see call sites for duffcopy/duffzero in
// BP-based profiling tools like Linux perf (which is the
// whole point of obj.Framepointer_enabled).
// whole point of maintaining frame pointers in Go).
// MOVQ BP, -16(SP)
// LEAQ -16(SP), BP
ab.Put(bpduff1)
@ -4852,7 +4852,7 @@ func (ab *AsmBuf) doasm(ctxt *obj.Link, cursym *obj.LSym, p *obj.Prog) {
r.Siz = 4
ab.PutInt32(0)
if ctxt.Framepointer_enabled && yt.zcase == Zcallduff && ctxt.Arch.Family == sys.AMD64 {
if yt.zcase == Zcallduff && ctxt.Arch.Family == sys.AMD64 {
// Pop BP pushed above.
// MOVQ 0(BP), BP
ab.Put(bpduff2)

2
src/cmd/internal/obj/x86/obj6.go
View File

@ -582,7 +582,7 @@ func preprocess(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) {
}
var bpsize int
if ctxt.Arch.Family == sys.AMD64 && ctxt.Framepointer_enabled &&
if ctxt.Arch.Family == sys.AMD64 &&
!p.From.Sym.NoFrame() && // (1) below
!(autoffset == 0 && p.From.Sym.NoSplit()) && // (2) below
!(autoffset == 0 && !hasCall) { // (3) below

7
src/cmd/internal/objabi/util.go
View File

@ -133,9 +133,8 @@ func init() {
}
}
func Framepointer_enabled(goos, goarch string) bool {
return framepointer_enabled != 0 && (goarch == "amd64" || goarch == "arm64" && (goos == "linux" || goos == "darwin"))
}
// Note: must agree with runtime.framepointer_enabled.
var Framepointer_enabled = GOARCH == "amd64" || GOARCH == "arm64" && (GOOS == "linux" || GOOS == "darwin")
func addexp(s string) {
// Could do general integer parsing here, but the runtime copy doesn't yet.
@ -159,7 +158,6 @@ func addexp(s string) {
}
var (
framepointer_enabled int = 1
Fieldtrack_enabled int
Preemptibleloops_enabled int
Staticlockranking_enabled int
@ -174,7 +172,6 @@ var exper = []struct {
val *int
}{
{"fieldtrack", &Fieldtrack_enabled},
{"framepointer", &framepointer_enabled},
{"preemptibleloops", &Preemptibleloops_enabled},
{"staticlockranking", &Staticlockranking_enabled},
}

8
src/cmd/link/internal/ld/lib.go
View File

@ -775,14 +775,6 @@ func (ctxt *Link) linksetup() {
sb.SetSize(0)
sb.AddUint8(uint8(objabi.GOARM))
}
if objabi.Framepointer_enabled(objabi.GOOS, objabi.GOARCH) {
fpe := ctxt.loader.LookupOrCreateSym("runtime.framepointer_enabled", 0)
sb := ctxt.loader.MakeSymbolUpdater(fpe)
sb.SetType(sym.SNOPTRDATA)
sb.SetSize(0)
sb.AddUint8(1)
}
} else {
// If OTOH the module does not contain the runtime package,
// create a local symbol for the moduledata.

7
src/runtime/cgocall.go
View File

@ -286,13 +286,8 @@ func cgocallbackg1(ctxt uintptr) {
// Additional two words (16-byte alignment) are for saving FP.
cb = (*args)(unsafe.Pointer(sp + 7*sys.PtrSize))
case "amd64":
// On amd64, stack frame is two words, plus caller PC.
if framepointer_enabled {
// In this case, there's also saved BP.
// On amd64, stack frame is two words, plus caller PC and BP.
cb = (*args)(unsafe.Pointer(sp + 4*sys.PtrSize))
break
}
cb = (*args)(unsafe.Pointer(sp + 3*sys.PtrSize))
case "386":
// On 386, stack frame is three words, plus caller PC.
cb = (*args)(unsafe.Pointer(sp + 4*sys.PtrSize))

3
src/runtime/proc.go
View File

@ -5459,9 +5459,6 @@ func setMaxThreads(in int) (out int) {
}
func haveexperiment(name string) bool {
if name == "framepointer" {
return framepointer_enabled // set by linker
}
x := sys.Goexperiment
for x != "" {
xname := ""

6
src/runtime/runtime2.go
View File

@ -329,7 +329,7 @@ type gobuf struct {
ctxt unsafe.Pointer
ret sys.Uintreg
lr uintptr
bp uintptr // for GOEXPERIMENT=framepointer
bp uintptr // for framepointer-enabled architectures
}
// sudog represents a g in a wait list, such as for sending/receiving
@ -1047,7 +1047,6 @@ var (
lfenceBeforeRdtsc bool
goarm uint8 // set by cmd/link on arm systems
framepointer_enabled bool // set by cmd/link
)
// Set by the linker so the runtime can determine the buildmode.
@ -1055,3 +1054,6 @@ var (
islibrary bool // -buildmode=c-shared
isarchive bool // -buildmode=c-archive
)
// Must agree with cmd/internal/objabi.Framepointer_enabled.
const framepointer_enabled = GOARCH == "amd64" || GOARCH == "arm64" && (GOOS == "linux" || GOOS == "darwin")

6
src/runtime/stack.go
View File

@ -648,12 +648,8 @@ func adjustframe(frame *stkframe, arg unsafe.Pointer) bool {
}
// Adjust saved base pointer if there is one.
// TODO what about arm64 frame pointer adjustment?
if sys.ArchFamily == sys.AMD64 && frame.argp-frame.varp == 2*sys.RegSize {
if !framepointer_enabled {
print("runtime: found space for saved base pointer, but no framepointer experiment\n")
print("argp=", hex(frame.argp), " varp=", hex(frame.varp), "\n")
throw("bad frame layout")
}
if stackDebug >= 3 {
print(" saved bp\n")
}

6
src/runtime/traceback.go
View File

@ -269,9 +269,9 @@ func gentraceback(pc0, sp0, lr0 uintptr, gp *g, skip int, pcbuf *uintptr, max in
frame.varp -= sys.RegSize
}
// If framepointer_enabled and there's a frame, then
// there's a saved bp here.
if frame.varp > frame.sp && (framepointer_enabled && GOARCH == "amd64" || GOARCH == "arm64") {
// For architectures with frame pointers, if there's
// a frame, then there's a saved frame pointer here.
if frame.varp > frame.sp && (GOARCH == "amd64" || GOARCH == "arm64") {
frame.varp -= sys.RegSize
}