From f4cbf3477f1456b4d28a7b74b31820ee60b7e6d1 Mon Sep 17 00:00:00 2001
From: David Chase <drchase@google.com>
Date: Mon, 31 Aug 2020 14:29:58 -0400
Subject: [PATCH] cmd/compile: allow directory specification for GOSSAFUNC
 output

This was useful for debugging failures occurring during make.bash.
The added flush also ensures that any hints in the GOSSAFUNC output
are flushed before fatal exit.

The environment variable GOSSADIR specifies where the SSA html debugging
files should be placed.  To avoid collisions, each one is written into
the [package].[functionOrMethod].html, where [package] is the filepath
separator separated package name, function is the function name, and method
is either (*Type).Method, or Type.Method, as appropriate.  Directories
are created as necessary to make this work.

Change-Id: I420927426b618b633bb1ffc51cf0f223b8f6d49c
Reviewed-on: https://go-review.googlesource.com/c/go/+/252338
Trust: David Chase <drchase@google.com>
Run-TryBot: David Chase <drchase@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
---
 src/cmd/compile/internal/gc/main.go     |  1 +
 src/cmd/compile/internal/gc/ssa.go      | 10 +++++++++-
 src/cmd/compile/internal/ssa/compile.go | 10 ++++++++++
 src/cmd/compile/internal/ssa/html.go    | 13 +++++++++----
 4 files changed, 29 insertions(+), 5 deletions(-)

diff --git a/src/cmd/compile/internal/gc/main.go b/src/cmd/compile/internal/gc/main.go
index 7ad3bfe0c8..e4e4ce72fd 100644
--- a/src/cmd/compile/internal/gc/main.go
+++ b/src/cmd/compile/internal/gc/main.go
@@ -516,6 +516,7 @@ func Main(archInit func(*Arch)) {
 	}
 
 	ssaDump = os.Getenv("GOSSAFUNC")
+	ssaDir = os.Getenv("GOSSADIR")
 	if ssaDump != "" {
 		if strings.HasSuffix(ssaDump, "+") {
 			ssaDump = ssaDump[:len(ssaDump)-1]
diff --git a/src/cmd/compile/internal/gc/ssa.go b/src/cmd/compile/internal/gc/ssa.go
index 7effa9bd4b..1d50cefe54 100644
--- a/src/cmd/compile/internal/gc/ssa.go
+++ b/src/cmd/compile/internal/gc/ssa.go
@@ -9,6 +9,7 @@ import (
 	"fmt"
 	"html"
 	"os"
+	"path/filepath"
 	"sort"
 
 	"bufio"
@@ -26,6 +27,7 @@ var ssaConfig *ssa.Config
 var ssaCaches []ssa.Cache
 
 var ssaDump string     // early copy of $GOSSAFUNC; the func name to dump output for
+var ssaDir string      // optional destination for ssa dump file
 var ssaDumpStdout bool // whether to dump to stdout
 var ssaDumpCFG string  // generate CFGs for these phases
 const ssaDumpFile = "ssa.html"
@@ -346,7 +348,13 @@ func buildssa(fn *Node, worker int) *ssa.Func {
 	s.f.Entry.Pos = fn.Pos
 
 	if printssa {
-		s.f.HTMLWriter = ssa.NewHTMLWriter(ssaDumpFile, s.f, ssaDumpCFG)
+		ssaDF := ssaDumpFile
+		if ssaDir != "" {
+			ssaDF = filepath.Join(ssaDir, myimportpath+"."+name+".html")
+			ssaD := filepath.Dir(ssaDF)
+			os.MkdirAll(ssaD, 0755)
+		}
+		s.f.HTMLWriter = ssa.NewHTMLWriter(ssaDF, s.f, ssaDumpCFG)
 		// TODO: generate and print a mapping from nodes to values and blocks
 		dumpSourcesColumn(s.f.HTMLWriter, fn)
 		s.f.HTMLWriter.WriteAST("AST", astBuf)
diff --git a/src/cmd/compile/internal/ssa/compile.go b/src/cmd/compile/internal/ssa/compile.go
index 3dec1cd85b..0664c0ba46 100644
--- a/src/cmd/compile/internal/ssa/compile.go
+++ b/src/cmd/compile/internal/ssa/compile.go
@@ -47,6 +47,9 @@ func Compile(f *Func) {
 			stack := make([]byte, 16384)
 			n := runtime.Stack(stack, false)
 			stack = stack[:n]
+			if f.HTMLWriter != nil {
+				f.HTMLWriter.flushPhases()
+			}
 			f.Fatalf("panic during %s while compiling %s:\n\n%v\n\n%s\n", phaseName, f.Name, err, stack)
 		}
 	}()
@@ -201,6 +204,13 @@ func (p *pass) addDump(s string) {
 	p.dump[s] = true
 }
 
+func (p *pass) String() string {
+	if p == nil {
+		return "nil pass"
+	}
+	return p.name
+}
+
 // Run consistency checker between each phase
 var (
 	checkEnabled  = false
diff --git a/src/cmd/compile/internal/ssa/html.go b/src/cmd/compile/internal/ssa/html.go
index c781ca92cc..a9d52fa4ee 100644
--- a/src/cmd/compile/internal/ssa/html.go
+++ b/src/cmd/compile/internal/ssa/html.go
@@ -28,18 +28,23 @@ type HTMLWriter struct {
 }
 
 func NewHTMLWriter(path string, f *Func, cfgMask string) *HTMLWriter {
+	path = strings.Replace(path, "/", string(filepath.Separator), -1)
 	out, err := os.OpenFile(path, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0644)
 	if err != nil {
 		f.Fatalf("%v", err)
 	}
-	pwd, err := os.Getwd()
-	if err != nil {
-		f.Fatalf("%v", err)
+	reportPath := path
+	if !filepath.IsAbs(reportPath) {
+		pwd, err := os.Getwd()
+		if err != nil {
+			f.Fatalf("%v", err)
+		}
+		reportPath = filepath.Join(pwd, path)
 	}
 	html := HTMLWriter{
 		w:    out,
 		Func: f,
-		path: filepath.Join(pwd, path),
+		path: reportPath,
 		dot:  newDotWriter(cfgMask),
 	}
 	html.start()
-- 
2.50.0