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>

4 files changed, 16 insertions, 16 deletions

diff --git a/src/runtime/abi_test.go b/src/runtime/abi_test.go
index fa365c0832..f50ed879d4 100644
--- a/src/runtime/abi_test.go
+++ b/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.regabi
+//go:build goexperiment.regabireflect
+// +build goexperiment.regabireflect
 
 // This file contains tests specific to making sure the register ABI
 // works in a bunch of contexts in the runtime.
diff --git a/src/runtime/asm_amd64.s b/src/runtime/asm_amd64.s
index ddd6a5bd5b..ab3f639929 100644
--- a/src/runtime/asm_amd64.s
+++ b/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)
diff --git a/src/runtime/race_amd64.s b/src/runtime/race_amd64.s
index 287bb9fc0a..5f6b86a1fe 100644
--- a/src/runtime/race_amd64.s
+++ b/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
diff --git a/src/runtime/sys_linux_amd64.s b/src/runtime/sys_linux_amd64.s
index d48573c2c5..584f2c5b1e 100644
--- a/src/runtime/sys_linux_amd64.s
+++ b/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.