all: delete regabireflect goexperiment

regabireflect goexperiment was helpful in the register ABI
development, to control code paths for reflect calls, before the
compiler can generate register ABI everywhere. It is not necessary
for now. Drop it.

Change-Id: I2731197d2f496e29616c426a01045c9b685946a4
Reviewed-on: https://go-review.googlesource.com/c/go/+/393362
Trust: Cherry Mui <cherryyz@google.com>
Run-TryBot: Cherry Mui <cherryyz@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Michael Knyszek <mknyszek@google.com>

src/internal/abi/abi_arm64.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build goexperiment.regabireflect
+//go:build goexperiment.regabiargs
 
 package abi
 

src/internal/abi/abi_generic.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build !goexperiment.regabireflect && !amd64
+//go:build !goexperiment.regabiargs && !amd64
 
 package abi
 

src/internal/abi/abi_ppc64x.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build goexperiment.regabireflect && (ppc64 || ppc64le)
+//go:build goexperiment.regabiargs && (ppc64 || ppc64le)
 
 package abi
 

src/internal/buildcfg/exp.go

@@ -54,7 +54,6 @@ func ParseGOEXPERIMENT(goos, goarch, goexp string) (flags, baseline goexperiment
 
 	baseline = goexperiment.Flags{
 		RegabiWrappers: regabiSupported,
-		RegabiReflect:  regabiSupported,
 		RegabiArgs:     regabiSupported,
 		PacerRedesign:  true,
 	}
@@ -81,7 +80,6 @@ func ParseGOEXPERIMENT(goos, goarch, goexp string) (flags, baseline goexperiment
 		// do the right thing.
 		names["regabi"] = func(v bool) {
 			flags.RegabiWrappers = v
-			flags.RegabiReflect = v
 			flags.RegabiArgs = v
 		}
 
@@ -113,17 +111,15 @@ func ParseGOEXPERIMENT(goos, goarch, goexp string) (flags, baseline goexperiment
 	// regabi is always enabled on amd64.
 	if goarch == "amd64" {
 		flags.RegabiWrappers = true
-		flags.RegabiReflect = true
 		flags.RegabiArgs = true
 	}
 	// regabi is only supported on amd64, arm64, ppc64 and ppc64le.
 	if !regabiSupported {
-		flags.RegabiReflect = false
 		flags.RegabiArgs = false
 	}
 	// Check regabi dependencies.
-	if flags.RegabiArgs && !(flags.RegabiWrappers && flags.RegabiReflect) {
-		err = fmt.Errorf("GOEXPERIMENT regabiargs requires regabiwrappers,regabireflect")
+	if flags.RegabiArgs && !flags.RegabiWrappers {
+		err = fmt.Errorf("GOEXPERIMENT regabiargs requires regabiwrappers")
 	}
 	return
 }

src/internal/goexperiment/exp_regabireflect_off.go

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

src/internal/goexperiment/exp_regabireflect_on.go

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

src/internal/goexperiment/flags.go

@@ -72,11 +72,6 @@ type Flags struct {
 	// ABI0 and ABIInternal functions. Without this, the ABIs are
 	// assumed to be identical so cross-ABI calls are direct.
 	RegabiWrappers 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
 	// RegabiArgs enables register arguments/results in all
 	// compiled Go functions.
 	//

src/reflect/abi_test.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build goexperiment.regabireflect && goexperiment.regabiargs
+//go:build goexperiment.regabiargs
 
 package reflect_test
 

src/runtime/abi_test.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build goexperiment.regabireflect
+//go:build goexperiment.regabiargs
 
 // This file contains tests specific to making sure the register ABI
 // works in a bunch of contexts in the runtime.

src/runtime/asm_arm64.s

@@ -317,7 +317,7 @@ TEXT runtime·morestack_noctxt(SB),NOSPLIT|NOFRAME,$0-0
 	MOVW	$0, R26
 	B runtime·morestack(SB)
 
-#ifdef GOEXPERIMENT_regabireflect
+#ifdef GOEXPERIMENT_regabiargs
 // spillArgs stores return values from registers to a *internal/abi.RegArgs in R20.
 TEXT ·spillArgs(SB),NOSPLIT,$0-0
 	MOVD	R0, (0*8)(R20)

src/runtime/asm_ppc64x.s

@@ -788,7 +788,7 @@ TEXT runtime·cputicks(SB),NOSPLIT,$0-8
 	MOVD	R3, ret+0(FP)
 	RET
 
-#ifdef GOEXPERIMENT_regabireflect
+#ifdef GOEXPERIMENT_regabiargs
 // spillArgs stores return values from registers to a *internal/abi.RegArgs in R20.
 TEXT runtime·spillArgs(SB),NOSPLIT,$0-0
 	MOVD    R3, 0(R20)