From 09a9ce60c7014ddff97690bf023ac5b2bfc142c7 Mon Sep 17 00:00:00 2001
From: David Chase <drchase@google.com>
Date: Thu, 17 Mar 2016 14:12:12 -0400
Subject: [PATCH] cmd/compile: get gcflags to bootstrap; ssa debug opts for
 "all"

This is intended to help debug compiler problems that pop
up in the bootstrap phase of make.bash.  GO_GCFLAGS does not
normally apply there.  Options-for-all phases is intended
to allow crude tracing (and full timing) by turning on timing
for all phases, not just one.

Phase names can also be specified using a regular expression,
for example
BOOT_GO_GCFLAGS=-d='ssa/~^.*scc$/off' \
GO_GCFLAGS='-d=ssa/~^.*scc$/off' ./make.bash

I just added this because it was the fastest way to get
me to a place where I could easily debug the compiler.

Change-Id: I0781f3e7c19651ae7452fa25c2d54c9a245ef62d
Reviewed-on: https://go-review.googlesource.com/20775
Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
---
 src/cmd/compile/internal/ssa/compile.go | 50 ++++++++++++++++++++++---
 src/cmd/dist/build.go                   |  6 +++
 src/make.bash                           |  3 +-
 3 files changed, 52 insertions(+), 7 deletions(-)

diff --git a/src/cmd/compile/internal/ssa/compile.go b/src/cmd/compile/internal/ssa/compile.go
index 7496aebcfc..b8e2b42c3e 100644
--- a/src/cmd/compile/internal/ssa/compile.go
+++ b/src/cmd/compile/internal/ssa/compile.go
@@ -7,6 +7,7 @@ package ssa
 import (
 	"fmt"
 	"log"
+	"regexp"
 	"runtime"
 	"strings"
 	"time"
@@ -121,10 +122,21 @@ var checkEnabled = false
 
 // PhaseOption sets the specified flag in the specified ssa phase,
 // returning empty string if this was successful or a string explaining
-// the error if it was not. A version of the phase name with "_"
-// replaced by " " is also checked for a match.
-// See gc/lex.go for dissection of the option string. Example use:
-// GO_GCFLAGS=-d=ssa/generic_cse/time,ssa/generic_cse/stats,ssa/generic_cse/debug=3 ./make.bash ...
+// the error if it was not.
+// A version of the phase name with "_" replaced by " " is also checked for a match.
+// If the phase name begins a '~' then the rest of the underscores-replaced-with-blanks
+// version is used as a regular expression to match the phase name(s).
+//
+// Special cases that have turned out to be useful:
+//  ssa/check/on enables checking after each phase
+//  ssa/all/time enables time reporting for all phases
+//
+// See gc/lex.go for dissection of the option string.
+// Example uses:
+//
+// GO_GCFLAGS=-d=ssa/generic_cse/time,ssa/generic_cse/stats,ssa/generic_cse/debug=3 ./make.bash
+//
+// BOOT_GO_GCFLAGS=-d='ssa/~^.*scc$/off' GO_GCFLAGS='-d=ssa/~^.*scc$/off' ./make.bash
 //
 func PhaseOption(phase, flag string, val int) string {
 	if phase == "check" && flag == "on" {
@@ -135,9 +147,32 @@ func PhaseOption(phase, flag string, val int) string {
 		checkEnabled = val == 0
 		return ""
 	}
+
+	alltime := false
+	if phase == "all" {
+		if flag == "time" {
+			alltime = val != 0
+		} else {
+			return fmt.Sprintf("Did not find a flag matching %s in -d=ssa/%s debug option", flag, phase)
+		}
+	}
+
 	underphase := strings.Replace(phase, "_", " ", -1)
+	var re *regexp.Regexp
+	if phase[0] == '~' {
+		r, ok := regexp.Compile(underphase[1:])
+		if ok != nil {
+			return fmt.Sprintf("Error %s in regexp for phase %s, flag %s", ok.Error(), phase, flag)
+		}
+		re = r
+	}
+	matchedOne := false
 	for i, p := range passes {
-		if p.name == phase || p.name == underphase {
+		if phase == "all" {
+			p.time = alltime
+			passes[i] = p
+			matchedOne = true
+		} else if p.name == phase || p.name == underphase || re != nil && re.MatchString(p.name) {
 			switch flag {
 			case "on":
 				p.disabled = val == 0
@@ -160,9 +195,12 @@ func PhaseOption(phase, flag string, val int) string {
 				return fmt.Sprintf("Cannot disable required SSA phase %s using -d=ssa/%s debug option", phase, phase)
 			}
 			passes[i] = p
-			return ""
+			matchedOne = true
 		}
 	}
+	if matchedOne {
+		return ""
+	}
 	return fmt.Sprintf("Did not find a phase matching %s in -d=ssa/... debug option", phase)
 }
 
diff --git a/src/cmd/dist/build.go b/src/cmd/dist/build.go
index e0e2ba1e3b..e35d96946e 100644
--- a/src/cmd/dist/build.go
+++ b/src/cmd/dist/build.go
@@ -31,6 +31,7 @@ var (
 	goroot           string
 	goroot_final     string
 	goextlinkenabled string
+	gogcflags        string // For running built compiler
 	workdir          string
 	tooldir          string
 	oldgoos          string
@@ -166,6 +167,8 @@ func xinit() {
 		goextlinkenabled = b
 	}
 
+	gogcflags = os.Getenv("GO_GCFLAGS")
+
 	b = os.Getenv("CC")
 	if b == "" {
 		// Use clang on OS X, because gcc is deprecated there.
@@ -687,6 +690,9 @@ func install(dir string) {
 		archive = b
 	}
 	compile := []string{pathf("%s/compile", tooldir), "-pack", "-o", b, "-p", pkg}
+	if gogcflags != "" {
+		compile = append(compile, gogcflags)
+	}
 	if dir == "runtime" {
 		compile = append(compile, "-+", "-asmhdr", pathf("%s/go_asm.h", workdir))
 	}
diff --git a/src/make.bash b/src/make.bash
index 21cc29730d..6e9c12901b 100755
--- a/src/make.bash
+++ b/src/make.bash
@@ -151,7 +151,8 @@ if [ "$1" = "--no-clean" ]; then
 	buildall=""
 	shift
 fi
-./cmd/dist/dist bootstrap $buildall $GO_DISTFLAGS -v # builds go_bootstrap
+
+GO_GCFLAGS="$BOOT_GO_GCFLAGS" ./cmd/dist/dist bootstrap $buildall $GO_DISTFLAGS -v # builds go_bootstrap
 # Delay move of dist tool to now, because bootstrap may clear tool directory.
 mv cmd/dist/dist "$GOTOOLDIR"/dist
 echo
-- 
2.48.1