[dev.typeparams] cmd/compile, runtime: always enable defer/go wrapping

Hardwire regabidefers to true. Remove it from GOEXPERIMENTs.

Fallback paths are not cleaned up in this CL. That will be done
in later CLs.

Change-Id: Iec1112a1e55d5f6ef70232a5ff6e702f649071c4
Reviewed-on: https://go-review.googlesource.com/c/go/+/325913
Trust: Cherry Mui <cherryyz@google.com>
Run-TryBot: Cherry Mui <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>

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

@@ -4696,7 +4696,7 @@ func (s *state) openDeferRecord(n *ir.CallExpr) {
 	var args []*ssa.Value
 	var argNodes []*ir.Name
 
-	if buildcfg.Experiment.RegabiDefer && (len(n.Args) != 0 || n.Op() == ir.OCALLINTER || n.X.Type().NumResults() != 0) {
+	if len(n.Args) != 0 || n.Op() == ir.OCALLINTER || n.X.Type().NumResults() != 0 {
 		s.Fatalf("defer call with arguments or results: %v", n)
 	}
 
@@ -4951,7 +4951,7 @@ func (s *state) call(n *ir.CallExpr, k callKind, returnResultAddr bool) *ssa.Val
 		}
 	}
 
-	if buildcfg.Experiment.RegabiDefer && k != callNormal && (len(n.Args) != 0 || n.Op() == ir.OCALLINTER || n.X.Type().NumResults() != 0) {
+	if k != callNormal && (len(n.Args) != 0 || n.Op() == ir.OCALLINTER || n.X.Type().NumResults() != 0) {
 		s.Fatalf("go/defer call with arguments: %v", n)
 	}
 

src/cmd/compile/internal/walk/order.go

@@ -7,7 +7,6 @@ package walk
 import (
 	"fmt"
 	"go/constant"
-	"internal/buildcfg"
 
 	"cmd/compile/internal/base"
 	"cmd/compile/internal/escape"
@@ -790,9 +789,7 @@ func (o *orderState) stmt(n ir.Node) {
 			n.Call = walkRecover(n.Call.(*ir.CallExpr), &init)
 			o.stmtList(init)
 		}
-		if buildcfg.Experiment.RegabiDefer {
 		o.wrapGoDefer(n)
-		}
 		o.out = append(o.out, n)
 		o.cleanTemp(t)
 

src/internal/buildcfg/exp.go

@@ -30,7 +30,6 @@ var experimentBaseline = goexperiment.Flags{
 	RegabiWrappers: regabiSupported,
 	RegabiG:        regabiSupported,
 	RegabiReflect:  regabiSupported,
-	RegabiDefer:    true,
 	RegabiArgs:     regabiSupported,
 }
 
@@ -70,7 +69,6 @@ func parseExperiments() goexperiment.Flags {
 			flags.RegabiWrappers = v
 			flags.RegabiG = v
 			flags.RegabiReflect = v
-			flags.RegabiDefer = v
 			flags.RegabiArgs = v
 		}
 
@@ -110,8 +108,8 @@ func parseExperiments() goexperiment.Flags {
 	if flags.RegabiG && !flags.RegabiWrappers {
 		Error = fmt.Errorf("GOEXPERIMENT regabig requires regabiwrappers")
 	}
-	if flags.RegabiArgs && !(flags.RegabiWrappers && flags.RegabiG && flags.RegabiReflect && flags.RegabiDefer) {
-		Error = fmt.Errorf("GOEXPERIMENT regabiargs requires regabiwrappers,regabig,regabireflect,regabidefer")
+	if flags.RegabiArgs && !(flags.RegabiWrappers && flags.RegabiG && flags.RegabiReflect) {
+		Error = fmt.Errorf("GOEXPERIMENT regabiargs requires regabiwrappers,regabig,regabireflect")
 	}
 	return flags
 }

src/internal/goexperiment/exp_regabidefer_off.go

@@ -1,9 +0,0 @@
-// Code generated by mkconsts.go. DO NOT EDIT.
-
-//go:build !goexperiment.regabidefer
-// +build !goexperiment.regabidefer
-
-package goexperiment
-
-const RegabiDefer = false
-const RegabiDeferInt = 0

src/internal/goexperiment/exp_regabidefer_on.go

@@ -1,9 +0,0 @@
-// Code generated by mkconsts.go. DO NOT EDIT.
-
-//go:build goexperiment.regabidefer
-// +build goexperiment.regabidefer
-
-package goexperiment
-
-const RegabiDefer = true
-const RegabiDeferInt = 1

src/internal/goexperiment/flags.go

@@ -78,9 +78,6 @@ type Flags struct {
 	// 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.
 	//

src/runtime/panic.go

@@ -6,7 +6,6 @@ package runtime
 
 import (
 	"internal/abi"
-	"internal/goexperiment"
 	"runtime/internal/atomic"
 	"runtime/internal/sys"
 	"unsafe"
@@ -236,7 +235,7 @@ func deferproc(siz int32, fn *funcval) { // arguments of fn follow fn
 		throw("defer on system stack")
 	}
 
-	if goexperiment.RegabiDefer && siz != 0 {
+	if true && siz != 0 {
 		// TODO: Make deferproc just take a func().
 		throw("defer with non-empty frame")
 	}
@@ -293,7 +292,7 @@ func deferprocStack(d *_defer) {
 		// go code on the system stack can't defer
 		throw("defer on system stack")
 	}
-	if goexperiment.RegabiDefer && d.siz != 0 {
+	if true && d.siz != 0 {
 		throw("defer with non-empty frame")
 	}
 	// siz and fn are already set.
@@ -395,7 +394,7 @@ func deferArgs(d *_defer) unsafe.Pointer {
 // that experiment, we should change the type of d.fn.
 //go:nosplit
 func deferFunc(d *_defer) func() {
-	if !goexperiment.RegabiDefer {
+	if false {
 		throw("requires GOEXPERIMENT=regabidefer")
 	}
 	var fn func()
@@ -655,7 +654,7 @@ func Goexit() {
 				addOneOpenDeferFrame(gp, 0, nil)
 			}
 		} else {
-			if goexperiment.RegabiDefer {
+			if true {
 				// Save the pc/sp in deferCallSave(), so we can "recover" back to this
 				// loop if necessary.
 				deferCallSave(&p, deferFunc(d))
@@ -857,7 +856,7 @@ func runOpenDeferFrame(gp *g, d *_defer) bool {
 		argWidth, fd = readvarintUnsafe(fd)
 		closureOffset, fd = readvarintUnsafe(fd)
 		nArgs, fd = readvarintUnsafe(fd)
-		if goexperiment.RegabiDefer && argWidth != 0 {
+		if true && argWidth != 0 {
 			throw("defer with non-empty frame")
 		}
 		if deferBits&(1<<i) == 0 {
@@ -885,7 +884,7 @@ func runOpenDeferFrame(gp *g, d *_defer) bool {
 		deferBits = deferBits &^ (1 << i)
 		*(*uint8)(unsafe.Pointer(d.varp - uintptr(deferBitsOffset))) = deferBits
 		p := d._panic
-		if goexperiment.RegabiDefer {
+		if true {
 			deferCallSave(p, deferFunc(d))
 		} else {
 			reflectcallSave(p, unsafe.Pointer(closure), deferArgs, argWidth)
@@ -913,7 +912,7 @@ func runOpenDeferFrame(gp *g, d *_defer) bool {
 // This is marked as a wrapper by the compiler so it doesn't appear in
 // tracebacks.
 func reflectcallSave(p *_panic, fn, arg unsafe.Pointer, argsize uint32) {
-	if goexperiment.RegabiDefer {
+	if true {
 		throw("not allowed with GOEXPERIMENT=regabidefer")
 	}
 	if p != nil {
@@ -939,7 +938,7 @@ func reflectcallSave(p *_panic, fn, arg unsafe.Pointer, argsize uint32) {
 // This is marked as a wrapper by the compiler so it doesn't appear in
 // tracebacks.
 func deferCallSave(p *_panic, fn func()) {
-	if !goexperiment.RegabiDefer {
+	if false {
 		throw("only allowed with GOEXPERIMENT=regabidefer")
 	}
 	if p != nil {
@@ -1042,7 +1041,7 @@ func gopanic(e interface{}) {
 		} else {
 			p.argp = unsafe.Pointer(getargp())
 
-			if goexperiment.RegabiDefer {
+			if true {
 				fn := deferFunc(d)
 				fn()
 			} else {

src/runtime/proc.go

@@ -7,7 +7,6 @@ package runtime
 import (
 	"internal/abi"
 	"internal/cpu"
-	"internal/goexperiment"
 	"runtime/internal/atomic"
 	"runtime/internal/sys"
 	"unsafe"
@@ -4259,7 +4258,7 @@ func newproc(siz int32, fn *funcval) {
 //
 //go:systemstack
 func newproc1(fn *funcval, argp unsafe.Pointer, narg int32, callergp *g, callerpc uintptr) *g {
-	if goexperiment.RegabiDefer && narg != 0 {
+	if true && narg != 0 {
 		// TODO: When we commit to GOEXPERIMENT=regabidefer,
 		// rewrite the comments for newproc and newproc1.
 		// newproc will no longer have a funny stack layout or

test/live.go

@@ -1,5 +1,5 @@
 // errorcheckwithauto -0 -l -live -wb=0 -d=ssa/insert_resched_checks/off
-// +build !ppc64,!ppc64le,goexperiment.regabidefer,!goexperiment.regabiargs
+// +build !ppc64,!ppc64le,!goexperiment.regabiargs
 
 // ppc64 needs a better tighten pass to make f18 pass
 // rescheduling checks need to be turned off because there are some live variables across the inserted check call

test/live_regabi.go

@@ -1,5 +1,5 @@
 // errorcheckwithauto -0 -l -live -wb=0 -d=ssa/insert_resched_checks/off
-// +build amd64,goexperiment.regabidefer,goexperiment.regabiargs
+// +build amd64,goexperiment.regabiargs
 
 // Copyright 2014 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style