all: explode GOEXPERIMENT=regabi into 5 sub-experiments

This separates GOEXPERIMENT=regabi into five sub-experiments:
regabiwrappers, regabig, regabireflect, regabidefer, and regabiargs.
Setting GOEXPERIMENT=regabi now implies the working subset of these
(currently, regabiwrappers, regabig, and regabireflect).

This simplifies testing, helps derisk the register ABI project,
and will also help with performance comparisons.

This replaces the -abiwrap flag to the compiler and linker with
the regabiwrappers experiment.

As part of this, regabiargs now enables registers for all calls
in the compiler. Previously, this was statically disabled in
regabiEnabledForAllCompilation, but now that we can control it
independently, this isn't necessary.

For #40724.

Change-Id: I5171e60cda6789031f2ef034cc2e7c5d62459122
Reviewed-on: https://go-review.googlesource.com/c/go/+/302070
Trust: Austin Clements <austin@google.com>
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: David Chase <drchase@google.com>

src/cmd/asm/internal/lex/input.go

@@ -46,12 +46,30 @@ func NewInput(name string) *Input {
 func predefine(defines flags.MultiFlag) map[string]*Macro {
 	macros := make(map[string]*Macro)
 
-	if *flags.CompilingRuntime && objabi.Regabi_enabled != 0 {
+	// Set macros for various GOEXPERIMENTs so we can easily
-		const name = "GOEXPERIMENT_REGABI"
+	// switch runtime assembly code based on them.
-		macros[name] = &Macro{
+	if *flags.CompilingRuntime {
-			name:   name,
+		set := func(name string) {
-			args:   nil,
+			macros[name] = &Macro{
-			tokens: Tokenize("1"),
+				name:   name,
+				args:   nil,
+				tokens: Tokenize("1"),
+			}
+		}
+		if objabi.Experiment.RegabiWrappers {
+			set("GOEXPERIMENT_REGABI_WRAPPERS")
+		}
+		if objabi.Experiment.RegabiG {
+			set("GOEXPERIMENT_REGABI_G")
+		}
+		if objabi.Experiment.RegabiReflect {
+			set("GOEXPERIMENT_REGABI_REFLECT")
+		}
+		if objabi.Experiment.RegabiDefer {
+			set("GOEXPERIMENT_REGABI_DEFER")
+		}
+		if objabi.Experiment.RegabiArgs {
+			set("GOEXPERIMENT_REGABI_ARGS")
 		}
 	}
 

src/cmd/compile/internal/amd64/ggen.go

@@ -85,7 +85,7 @@ func zerorange(pp *objw.Progs, p *obj.Prog, off, cnt int64, state *uint32) *obj.
 		}
 		p = pp.Append(p, x86.AMOVQ, obj.TYPE_REG, x86.REG_AX, 0, obj.TYPE_MEM, x86.REG_SP, off)
 	} else if !isPlan9 && cnt <= int64(8*types.RegSize) {
-		if objabi.Regabi_enabled == 0 && *state&x15 == 0 {
+		if !objabi.Experiment.RegabiG && *state&x15 == 0 {
 			p = pp.Append(p, x86.AXORPS, obj.TYPE_REG, x86.REG_X15, 0, obj.TYPE_REG, x86.REG_X15, 0)
 			*state |= x15
 		}
@@ -98,7 +98,7 @@ func zerorange(pp *objw.Progs, p *obj.Prog, off, cnt int64, state *uint32) *obj.
 			p = pp.Append(p, x86.AMOVUPS, obj.TYPE_REG, x86.REG_X15, 0, obj.TYPE_MEM, x86.REG_SP, off+cnt-int64(16))
 		}
 	} else if !isPlan9 && (cnt <= int64(128*types.RegSize)) {
-		if objabi.Regabi_enabled == 0 && *state&x15 == 0 {
+		if !objabi.Experiment.RegabiG && *state&x15 == 0 {
 			p = pp.Append(p, x86.AXORPS, obj.TYPE_REG, x86.REG_X15, 0, obj.TYPE_REG, x86.REG_X15, 0)
 			*state |= x15
 		}

src/cmd/compile/internal/amd64/ssa.go

@@ -827,8 +827,8 @@ func ssaGenValue(s *ssagen.State, v *ssa.Value) {
 		if s.ABI != obj.ABIInternal {
 			v.Fatalf("MOVOstorezero can be only used in ABIInternal functions")
 		}
-		if !(objabi.Regabi_enabled == 1 && base.Flag.ABIWrap) {
+		if !objabi.Experiment.RegabiG {
-			// zeroing X15 manually if wrappers are not used
+			// zero X15 manually
 			opregreg(s, x86.AXORPS, x86.REG_X15, x86.REG_X15)
 		}
 		p := s.Prog(v.Op.Asm())
@@ -921,8 +921,8 @@ func ssaGenValue(s *ssagen.State, v *ssa.Value) {
 		if s.ABI != obj.ABIInternal {
 			v.Fatalf("MOVOconst can be only used in ABIInternal functions")
 		}
-		if !(objabi.Regabi_enabled == 1 && base.Flag.ABIWrap) {
+		if !objabi.Experiment.RegabiG {
-			// zeroing X15 manually if wrappers are not used
+			// zero X15 manually
 			opregreg(s, x86.AXORPS, x86.REG_X15, x86.REG_X15)
 		}
 		off := duffStart(v.AuxInt)
@@ -1004,20 +1004,20 @@ func ssaGenValue(s *ssagen.State, v *ssa.Value) {
 		// Closure pointer is DX.
 		ssagen.CheckLoweredGetClosurePtr(v)
 	case ssa.OpAMD64LoweredGetG:
-		if objabi.Regabi_enabled == 1 && base.Flag.ABIWrap {
+		if objabi.Experiment.RegabiG {
 			v.Fatalf("LoweredGetG should not appear in new ABI")
 		}
 		r := v.Reg()
 		getgFromTLS(s, r)
 	case ssa.OpAMD64CALLstatic:
-		if objabi.Regabi_enabled == 1 && s.ABI == obj.ABI0 && v.Aux.(*ssa.AuxCall).Fn.ABI() == obj.ABIInternal {
+		if objabi.Experiment.RegabiG && s.ABI == obj.ABI0 && v.Aux.(*ssa.AuxCall).Fn.ABI() == obj.ABIInternal {
 			// zeroing X15 when entering ABIInternal from ABI0
 			opregreg(s, x86.AXORPS, x86.REG_X15, x86.REG_X15)
 			// set G register from TLS
 			getgFromTLS(s, x86.REG_R14)
 		}
 		s.Call(v)
-		if objabi.Regabi_enabled == 1 && s.ABI == obj.ABIInternal && v.Aux.(*ssa.AuxCall).Fn.ABI() == obj.ABI0 {
+		if objabi.Experiment.RegabiG && s.ABI == obj.ABIInternal && v.Aux.(*ssa.AuxCall).Fn.ABI() == obj.ABI0 {
 			// zeroing X15 when entering ABIInternal from ABI0
 			opregreg(s, x86.AXORPS, x86.REG_X15, x86.REG_X15)
 			// set G register from TLS
@@ -1304,7 +1304,7 @@ func ssaGenBlock(s *ssagen.State, b, next *ssa.Block) {
 	case ssa.BlockRet:
 		s.Prog(obj.ARET)
 	case ssa.BlockRetJmp:
-		if objabi.Regabi_enabled == 1 && s.ABI == obj.ABI0 && b.Aux.(*obj.LSym).ABI() == obj.ABIInternal {
+		if objabi.Experiment.RegabiG && s.ABI == obj.ABI0 && b.Aux.(*obj.LSym).ABI() == obj.ABIInternal {
 			// zeroing X15 when entering ABIInternal from ABI0
 			opregreg(s, x86.AXORPS, x86.REG_X15, x86.REG_X15)
 			// set G register from TLS

src/cmd/compile/internal/base/flag.go

@@ -82,7 +82,6 @@ type CmdFlags struct {
 	CompilingRuntime bool "flag:\"+\" help:\"compiling runtime\""
 
 	// Longer names
-	ABIWrap            bool         "help:\"enable generation of ABI wrappers\""
 	ABIWrapLimit       int          "help:\"emit at most N ABI wrappers (for debugging)\""
 	AsmHdr             string       "help:\"write assembly header to `file`\""
 	Bench              string       "help:\"append benchmark times to `file`\""
@@ -147,7 +146,6 @@ func ParseFlags() {
 	Flag.LowerP = &Ctxt.Pkgpath
 	Flag.LowerV = &Ctxt.Debugvlog
 
-	Flag.ABIWrap = objabi.Regabi_enabled != 0
 	Flag.Dwarf = objabi.GOARCH != "wasm"
 	Flag.DwarfBASEntries = &Ctxt.UseBASEntries
 	Flag.DwarfLocationLists = &Ctxt.Flag_locationlists

src/cmd/compile/internal/ssa/config.go

@@ -6,7 +6,6 @@ package ssa
 
 import (
 	"cmd/compile/internal/abi"
-	"cmd/compile/internal/base"
 	"cmd/compile/internal/ir"
 	"cmd/compile/internal/types"
 	"cmd/internal/obj"
@@ -204,7 +203,7 @@ func NewConfig(arch string, types Types, ctxt *obj.Link, optimize bool) *Config
 		c.floatParamRegs = paramFloatRegAMD64
 		c.FPReg = framepointerRegAMD64
 		c.LinkReg = linkRegAMD64
-		c.hasGReg = base.Flag.ABIWrap
+		c.hasGReg = objabi.Experiment.RegabiG
 	case "386":
 		c.PtrSize = 4
 		c.RegSize = 4

src/cmd/compile/internal/ssa/gen/AMD64.rules

@@ -460,7 +460,7 @@
 (IsInBounds idx len) => (SETB (CMPQ idx len))
 (IsSliceInBounds idx len) => (SETBE (CMPQ idx len))
 (NilCheck ...) => (LoweredNilCheck ...)
-(GetG mem) && !(objabi.Regabi_enabled == 1 && base.Flag.ABIWrap) => (LoweredGetG mem) // only lower in old ABI. in new ABI we have a G register.
+(GetG mem) && !objabi.Experiment.RegabiG => (LoweredGetG mem) // only lower in old ABI. in new ABI we have a G register.
 (GetClosurePtr ...) => (LoweredGetClosurePtr ...)
 (GetCallerPC ...) => (LoweredGetCallerPC ...)
 (GetCallerSP ...) => (LoweredGetCallerSP ...)

src/cmd/compile/internal/ssa/rewriteAMD64.go

@@ -5,7 +5,6 @@ package ssa
 
 import "math"
 import "cmd/internal/objabi"
-import "cmd/compile/internal/base"
 import "cmd/compile/internal/types"
 
 func rewriteValueAMD64(v *Value) bool {
@@ -30273,11 +30272,11 @@ func rewriteValueAMD64_OpFloor(v *Value) bool {
 func rewriteValueAMD64_OpGetG(v *Value) bool {
 	v_0 := v.Args[0]
 	// match: (GetG mem)
-	// cond: !(objabi.Regabi_enabled == 1 && base.Flag.ABIWrap)
+	// cond: !objabi.Experiment.RegabiG
 	// result: (LoweredGetG mem)
 	for {
 		mem := v_0
-		if !(!(objabi.Regabi_enabled == 1 && base.Flag.ABIWrap)) {
+		if !(!objabi.Experiment.RegabiG) {
 			break
 		}
 		v.reset(OpAMD64LoweredGetG)

src/cmd/compile/internal/ssagen/abi.go

@@ -24,7 +24,7 @@ import (
 // useNewABIWrapGen returns TRUE if the compiler should generate an
 // ABI wrapper for the function 'f'.
 func useABIWrapGen(f *ir.Func) bool {
-	if !base.Flag.ABIWrap {
+	if !objabi.Experiment.RegabiWrappers {
 		return false
 	}
 
@@ -140,7 +140,7 @@ func ReadSymABIs(file, myimportpath string) {
 func InitLSym(f *ir.Func, hasBody bool) {
 	// FIXME: for new-style ABI wrappers, we set up the lsym at the
 	// point the wrapper is created.
-	if f.LSym != nil && base.Flag.ABIWrap {
+	if f.LSym != nil && objabi.Experiment.RegabiWrappers {
 		return
 	}
 	staticdata.NeedFuncSym(f.Sym())

src/cmd/compile/internal/ssagen/ssa.go

@@ -261,8 +261,7 @@ func regAbiForFuncType(ft *types.Func) bool {
 }
 
 func regabiEnabledForAllCompilation() bool {
-	// TODO compiler does not yet change behavior for GOEXPERIMENT=regabi
+	return objabi.Experiment.RegabiArgs
-	return false && objabi.Regabi_enabled != 0
 }
 
 // getParam returns the Field of ith param of node n (which is a
@@ -7448,7 +7447,7 @@ func clobberBase(n ir.Node) ir.Node {
 //
 func callTargetLSym(callee *ir.Name, callerLSym *obj.LSym) *obj.LSym {
 	lsym := callee.Linksym()
-	if !base.Flag.ABIWrap {
+	if !objabi.Experiment.RegabiWrappers {
 		return lsym
 	}
 	fn := callee.Func

src/cmd/internal/obj/x86/obj6.go

@@ -646,13 +646,13 @@ 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()) {
-		if ctxt.Arch.Family == sys.AMD64 && objabi.Regabi_enabled != 0 && cursym.ABI() == obj.ABIInternal {
+		if ctxt.Arch.Family == sys.AMD64 && objabi.Experiment.RegabiG && cursym.ABI() == obj.ABIInternal {
 			regg = REGG // use the g register directly in ABIInternal
 		} else {
 			p = obj.Appendp(p, newprog)
 			regg = REG_CX
 			if ctxt.Arch.Family == sys.AMD64 {
-				// Using this register means that stacksplit works w/ //go:registerparams even when objabi.Regabi_enabled == 0
+				// Using this register means that stacksplit works w/ //go:registerparams even when !objabi.Experiment.RegabiG
 				regg = REGG // == REG_R14
 			}
 			p = load_g(ctxt, p, newprog, regg) // load g into regg

src/cmd/internal/objabi/util.go

@@ -146,7 +146,28 @@ func init() {
 
 	// regabi is only supported on amd64.
 	if GOARCH != "amd64" {
-		Regabi_enabled = 0
+		Experiment.regabi = false
+		Experiment.RegabiWrappers = false
+		Experiment.RegabiG = false
+		Experiment.RegabiReflect = false
+		Experiment.RegabiDefer = false
+		Experiment.RegabiArgs = false
+	}
+	// Setting regabi sets working sub-experiments.
+	if Experiment.regabi {
+		Experiment.RegabiWrappers = true
+		Experiment.RegabiG = true
+		Experiment.RegabiReflect = true
+		// Not ready yet:
+		//Experiment.RegabiDefer = true
+		//Experiment.RegabiArgs = true
+	}
+	// Check regabi dependencies.
+	if Experiment.RegabiG && !Experiment.RegabiWrappers {
+		panic("GOEXPERIMENT regabig requires regabiwrappers")
+	}
+	if Experiment.RegabiArgs && !(Experiment.RegabiWrappers && Experiment.RegabiReflect && Experiment.RegabiDefer) {
+		panic("GOEXPERIMENT regabiargs requires regabiwrappers,regabireflect,regabidefer")
 	}
 
 	// Set GOEXPERIMENT to the parsed and canonicalized set of experiments.
@@ -186,9 +207,42 @@ var (
 	Fieldtrack_enabled        int
 	Preemptibleloops_enabled  int
 	Staticlockranking_enabled int
-	Regabi_enabled            int
 )
 
+// Experiment contains flags for GOEXPERIMENTs.
+//
+// TODO(austin): Move the package-level experiment flags into this.
+var Experiment ExpFlags
+
+type ExpFlags struct {
+	// regabi is split into several sub-experiments that can be
+	// enabled individually. GOEXPERIMENT=regabi implies the
+	// subset that are currently "working". Not all combinations work.
+	regabi bool
+	// RegabiWrappers enables ABI wrappers for calling between
+	// ABI0 and ABIInternal functions. Without this, the ABIs are
+	// assumed to be identical so cross-ABI calls are direct.
+	RegabiWrappers bool
+	// RegabiG enables dedicated G and zero registers in
+	// ABIInternal.
+	//
+	// Requires wrappers because it makes the ABIs incompatible.
+	RegabiG bool
+	// RegabiReflect enables the register-passing paths in
+	// reflection calls. This is also gated by intArgRegs in
+	// reflect and runtime (which are disabled by default) so it
+	// can be used in targeted tests.
+	RegabiReflect bool
+	// RegabiDefer enables desugaring defer and go calls
+	// into argument-less closures.
+	RegabiDefer bool
+	// RegabiArgs enables register arguments/results in all
+	// compiled Go functions.
+	//
+	// Requires wrappers, reflect, defer.
+	RegabiArgs bool
+}
+
 // Toolchain experiments.
 // These are controlled by the GOEXPERIMENT environment
 // variable recorded when the toolchain is built.
@@ -199,7 +253,12 @@ var exper = []struct {
 	{"fieldtrack", &Fieldtrack_enabled},
 	{"preemptibleloops", &Preemptibleloops_enabled},
 	{"staticlockranking", &Staticlockranking_enabled},
-	{"regabi", &Regabi_enabled},
+	{"regabi", &Experiment.regabi},
+	{"regabiwrappers", &Experiment.RegabiWrappers},
+	{"regabig", &Experiment.RegabiG},
+	{"regabireflect", &Experiment.RegabiReflect},
+	{"regabidefer", &Experiment.RegabiDefer},
+	{"regabiargs", &Experiment.RegabiArgs},
 }
 
 var defaultExpstring string

src/cmd/link/internal/ld/lib.go

@@ -493,7 +493,7 @@ func (ctxt *Link) loadlib() {
 	default:
 		log.Fatalf("invalid -strictdups flag value %d", *FlagStrictDups)
 	}
-	if !*flagAbiWrap || ctxt.linkShared {
+	if !objabi.Experiment.RegabiWrappers || ctxt.linkShared {
 		// Use ABI aliases if ABI wrappers are not used.
 		// TODO: for now we still use ABI aliases in shared linkage, even if
 		// the wrapper is enabled.
@@ -2116,7 +2116,7 @@ func ldshlibsyms(ctxt *Link, shlib string) {
 
 	// collect text symbol ABI versions.
 	symabi := make(map[string]int) // map (unmangled) symbol name to version
-	if *flagAbiWrap {
+	if objabi.Experiment.RegabiWrappers {
 		for _, elfsym := range syms {
 			if elf.ST_TYPE(elfsym.Info) != elf.STT_FUNC {
 				continue
@@ -2144,7 +2144,7 @@ func ldshlibsyms(ctxt *Link, shlib string) {
 		symname := elfsym.Name // (unmangled) symbol name
 		if elf.ST_TYPE(elfsym.Info) == elf.STT_FUNC && strings.HasPrefix(elfsym.Name, "type.") {
 			ver = sym.SymVerABIInternal
-		} else if *flagAbiWrap && elf.ST_TYPE(elfsym.Info) == elf.STT_FUNC {
+		} else if objabi.Experiment.RegabiWrappers && elf.ST_TYPE(elfsym.Info) == elf.STT_FUNC {
 			if strings.HasSuffix(elfsym.Name, ".abiinternal") {
 				ver = sym.SymVerABIInternal
 				symname = strings.TrimSuffix(elfsym.Name, ".abiinternal")
@@ -2194,7 +2194,7 @@ func ldshlibsyms(ctxt *Link, shlib string) {
 		// mangle Go function names in the .so to include the
 		// ABI.
 		if elf.ST_TYPE(elfsym.Info) == elf.STT_FUNC && ver == 0 {
-			if *flagAbiWrap {
+			if objabi.Experiment.RegabiWrappers {
 				if _, ok := symabi[symname]; ok {
 					continue // only use alias for functions w/o ABI wrappers
 				}

src/cmd/link/internal/ld/main.go

@@ -95,7 +95,6 @@ var (
 	cpuprofile        = flag.String("cpuprofile", "", "write cpu profile to `file`")
 	memprofile        = flag.String("memprofile", "", "write memory profile to `file`")
 	memprofilerate    = flag.Int64("memprofilerate", 0, "set runtime.MemProfileRate to `rate`")
-	flagAbiWrap       = flag.Bool("abiwrap", objabi.Regabi_enabled != 0, "support ABI wrapper functions")
 	benchmarkFlag     = flag.String("benchmark", "", "set to 'mem' or 'cpu' to enable phase benchmarking")
 	benchmarkFileFlag = flag.String("benchmarkprofile", "", "emit phase profiles to `base`_phase.{cpu,mem}prof")
 )

src/cmd/link/internal/ld/symtab.go

@@ -121,7 +121,7 @@ func putelfsym(ctxt *Link, x loader.Sym, typ elf.SymType, curbind elf.SymBind) {
 	// sym or marker relocation to associate the wrapper with the
 	// wrapped function.
 	//
-	if *flagAbiWrap {
+	if objabi.Experiment.RegabiWrappers {
 		if !ldr.IsExternal(x) && ldr.SymType(x) == sym.STEXT {
 			// First case
 			if ldr.SymVersion(x) == sym.SymVerABIInternal {

src/internal/abi/abi_amd64.go

@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build goexperiment.regabi
+//go:build goexperiment.regabireflect
-// +build goexperiment.regabi
+// +build goexperiment.regabireflect
 
 package abi
 

src/internal/abi/abi_generic.go

@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build !goexperiment.regabi
+//go:build !goexperiment.regabireflect
-// +build !goexperiment.regabi
+// +build !goexperiment.regabireflect
 
 package abi
 

src/runtime/abi_test.go

@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build goexperiment.regabi
+//go:build goexperiment.regabireflect
-//go:build goexperiment.regabi
+// +build goexperiment.regabireflect
 
 // This file contains tests specific to making sure the register ABI
 // works in a bunch of contexts in the runtime.

src/runtime/asm_amd64.s

@@ -442,7 +442,7 @@ TEXT runtime·morestack_noctxt(SB),NOSPLIT,$0
 	MOVL	$0, DX
 	JMP	runtime·morestack(SB)
 
-#ifdef GOEXPERIMENT_REGABI
+#ifdef GOEXPERIMENT_REGABI_REFLECT
 // spillArgs stores return values from registers to a *internal/abi.RegArgs in R12.
 TEXT spillArgs<>(SB),NOSPLIT,$0-0
 	MOVQ AX, 0(R12)
@@ -660,7 +660,7 @@ TEXT runtime·jmpdefer(SB), NOSPLIT, $0-16
 // or else unwinding from systemstack_switch is incorrect.
 // Smashes R9.
 TEXT gosave_systemstack_switch<>(SB),NOSPLIT,$0
-#ifndef GOEXPERIMENT_REGABI
+#ifndef GOEXPERIMENT_REGABI_G
 	get_tls(R14)
 	MOVQ	g(R14), R14
 #endif
@@ -1461,7 +1461,7 @@ TEXT runtime·addmoduledata(SB),NOSPLIT,$0-0
 // signals. It is quite painful to set X15 in the signal context,
 // so we do it here.
 TEXT ·sigpanic0<ABIInternal>(SB),NOSPLIT,$0-0
-#ifdef GOEXPERIMENT_REGABI
+#ifdef GOEXPERIMENT_REGABI_G
 	get_tls(R14)
 	MOVQ	g(R14), R14
 	XORPS	X15, X15
@@ -1483,7 +1483,7 @@ TEXT runtime·gcWriteBarrier<ABIInternal>(SB),NOSPLIT,$112
 	MOVQ	R13, 104(SP)
 	// TODO: Consider passing g.m.p in as an argument so they can be shared
 	// across a sequence of write barriers.
-#ifdef GOEXPERIMENT_REGABI
+#ifdef GOEXPERIMENT_REGABI_G
 	MOVQ	g_m(R14), R13
 #else
 	get_tls(R13)

src/runtime/race_amd64.s

@@ -146,7 +146,7 @@ TEXT	runtime·racewriterangepc1(SB), NOSPLIT, $0-24
 // If addr (RARG1) is out of range, do nothing.
 // Otherwise, setup goroutine context and invoke racecall. Other arguments already set.
 TEXT	racecalladdr<>(SB), NOSPLIT, $0-0
-#ifndef GOEXPERIMENT_REGABI
+#ifndef GOEXPERIMENT_REGABI_G
 	get_tls(R12)
 	MOVQ	g(R12), R14
 #endif
@@ -177,7 +177,7 @@ TEXT	runtime·racefuncenter(SB), NOSPLIT, $0-8
 // R11 = caller's return address
 TEXT	racefuncenter<>(SB), NOSPLIT, $0-0
 	MOVQ	DX, BX		// save function entry context (for closures)
-#ifndef GOEXPERIMENT_REGABI
+#ifndef GOEXPERIMENT_REGABI_G
 	get_tls(R12)
 	MOVQ	g(R12), R14
 #endif
@@ -193,7 +193,7 @@ TEXT	racefuncenter<>(SB), NOSPLIT, $0-0
 // func runtime·racefuncexit()
 // Called from instrumented code.
 TEXT	runtime·racefuncexit(SB), NOSPLIT, $0-0
-#ifndef GOEXPERIMENT_REGABI
+#ifndef GOEXPERIMENT_REGABI_G
 	get_tls(R12)
 	MOVQ	g(R12), R14
 #endif
@@ -355,7 +355,7 @@ racecallatomic_data:
 	JAE	racecallatomic_ignore
 racecallatomic_ok:
 	// Addr is within the good range, call the atomic function.
-#ifndef GOEXPERIMENT_REGABI
+#ifndef GOEXPERIMENT_REGABI_G
 	get_tls(R12)
 	MOVQ	g(R12), R14
 #endif
@@ -370,7 +370,7 @@ racecallatomic_ignore:
 	// An attempt to synchronize on the address would cause crash.
 	MOVQ	AX, BX	// remember the original function
 	MOVQ	$__tsan_go_ignore_sync_begin(SB), AX
-#ifndef GOEXPERIMENT_REGABI
+#ifndef GOEXPERIMENT_REGABI_G
 	get_tls(R12)
 	MOVQ	g(R12), R14
 #endif
@@ -401,7 +401,7 @@ TEXT	runtime·racecall(SB), NOSPLIT, $0-0
 
 // Switches SP to g0 stack and calls (AX). Arguments already set.
 TEXT	racecall<>(SB), NOSPLIT, $0-0
-#ifndef GOEXPERIMENT_REGABI
+#ifndef GOEXPERIMENT_REGABI_G
 	get_tls(R12)
 	MOVQ	g(R12), R14
 #endif

src/runtime/sys_linux_amd64.s

@@ -215,7 +215,7 @@ TEXT runtime·walltime1(SB),NOSPLIT,$16-12
 
 	MOVQ	SP, R12	// Save old SP; R12 unchanged by C code.
 
-#ifdef GOEXPERIMENT_REGABI
+#ifdef GOEXPERIMENT_REGABI_G
 	MOVQ	g_m(R14), BX // BX unchanged by C code.
 #else
 	get_tls(CX)
@@ -236,7 +236,7 @@ TEXT runtime·walltime1(SB),NOSPLIT,$16-12
 	MOVQ	CX, m_vdsoPC(BX)
 	MOVQ	DX, m_vdsoSP(BX)
 
-#ifdef GOEXPERIMENT_REGABI
+#ifdef GOEXPERIMENT_REGABI_G
 	CMPQ	R14, m_curg(BX)	// Only switch if on curg.
 #else
 	CMPQ	AX, m_curg(BX)	// Only switch if on curg.
@@ -283,7 +283,7 @@ TEXT runtime·nanotime1(SB),NOSPLIT,$16-8
 
 	MOVQ	SP, R12	// Save old SP; R12 unchanged by C code.
 
-#ifdef GOEXPERIMENT_REGABI
+#ifdef GOEXPERIMENT_REGABI_G
 	MOVQ	g_m(R14), BX // BX unchanged by C code.
 #else
 	get_tls(CX)
@@ -304,7 +304,7 @@ TEXT runtime·nanotime1(SB),NOSPLIT,$16-8
 	MOVQ	CX, m_vdsoPC(BX)
 	MOVQ	DX, m_vdsoSP(BX)
 
-#ifdef GOEXPERIMENT_REGABI
+#ifdef GOEXPERIMENT_REGABI_G
 	CMPQ	R14, m_curg(BX)	// Only switch if on curg.
 #else
 	CMPQ	AX, m_curg(BX)	// Only switch if on curg.