From: Josh Bleecher Snyder <josharian@gmail.com>
Date: Fri, 20 Jan 2017 16:11:34 +0000 (-0800)
Subject: cmd/compile: fix compilebench -alloc
X-Git-Tag: go1.8rc3~1^2~17
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=e8d5989ed1272bed3600193003ebc9980bcb9275;p=gostls13.git

cmd/compile: fix compilebench -alloc

pprof.WriteHeapProfile is shorthand for
pprof.Lookup("heap").WriteTo(f, 0).
The second parameter is debug.
If it is non-zero, pprof writes legacy-format
pprof output, which compilebench can parse.

Fixes #18641

Change-Id: Ica69adeb9809e9b5933aed943dcf4a07910e43fc
Reviewed-on: https://go-review.googlesource.com/35484
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
---

diff --git a/src/cmd/compile/internal/gc/util.go b/src/cmd/compile/internal/gc/util.go
index bb5cede5a6..c62bd00808 100644
--- a/src/cmd/compile/internal/gc/util.go
+++ b/src/cmd/compile/internal/gc/util.go
@@ -57,8 +57,13 @@ func startProfile() {
 			Fatalf("%v", err)
 		}
 		atExit(func() {
-			runtime.GC() // profile all outstanding allocations
-			if err := pprof.WriteHeapProfile(f); err != nil {
+			// Profile all outstanding allocations.
+			runtime.GC()
+			// compilebench parses the memory profile to extract memstats,
+			// which are only written in the legacy pprof format.
+			// See golang.org/issue/18641 and runtime/pprof/pprof.go:writeHeap.
+			const writeLegacyFormat = 1
+			if err := pprof.Lookup("heap").WriteTo(f, writeLegacyFormat); err != nil {
 				Fatalf("%v", err)
 			}
 		})