From: Ian Lance Taylor <iant@golang.org>
Date: Fri, 12 Apr 2013 12:23:38 +0000 (-0700)
Subject: runtime: add a hook to disable precise GC
X-Git-Tag: go1.1rc2~111
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=709e03f43dce8e6fde3398e01255c08d22cb1ee2;p=gostls13.git

runtime: add a hook to disable precise GC

This will let us ask people to rebuild the Go system without
precise GC, and then rebuild and retest their program, to see
if precise GC is causing whatever problem they are having.

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/8700043
---

diff --git a/src/pkg/runtime/mgc0.c b/src/pkg/runtime/mgc0.c
index 64b5f0464a..f9dbdbb4a1 100644
--- a/src/pkg/runtime/mgc0.c
+++ b/src/pkg/runtime/mgc0.c
@@ -19,6 +19,7 @@ enum {
 	DebugMark = 0,  // run second pass to check mark
 	CollectStats = 0,
 	ScanStackByFrames = 0,
+	IgnorePreciseGC = 0,
 
 	// Four bits per word (see #defines below).
 	wordsPerBitmapWord = sizeof(void*)*8/4,
@@ -771,6 +772,9 @@ scanblock(Workbuf *wbuf, Obj *wp, uintptr nobj, bool keepworking)
 			pc = defaultProg;
 		}
 
+		if(IgnorePreciseGC)
+			pc = defaultProg;
+
 		pc++;
 		stack_top.b = (uintptr)b;