From: ian <ian@138bc75d-0d04-0410-961f-82ee72b054a4>
Date: Tue, 15 May 2012 18:57:03 +0000 (+0000)
Subject: runtime: Make all variables used across getcontext volatile.
X-Git-Url: http://git.sourceforge.jp/view?p=pf3gnuchains%2Fgcc-fork.git;a=commitdiff_plain;h=c267659c24d255e7a6e5d803f42696cecfe89525

runtime: Make all variables used across getcontext volatile.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/branches/gcc-4_7-branch@187550 138bc75d-0d04-0410-961f-82ee72b054a4
---

diff --git a/libgo/runtime/proc.c b/libgo/runtime/proc.c
index eabd5e82664..0862c604640 100644
--- a/libgo/runtime/proc.c
+++ b/libgo/runtime/proc.c
@@ -1322,7 +1322,7 @@ __go_go(void (*fn)(void*), void* arg)
 {
 	byte *sp;
 	size_t spsize;
-	G * volatile newg;	// volatile to avoid longjmp warning
+	G *newg;
 
 	schedlock();
 
@@ -1363,19 +1363,26 @@ __go_go(void (*fn)(void*), void* arg)
 	if(sp == nil)
 		runtime_throw("nil g->stack0");
 
-	getcontext(&newg->context);
-	newg->context.uc_stack.ss_sp = sp;
+	{
+		// Avoid warnings about variables clobbered by
+		// longjmp.
+		byte * volatile vsp = sp;
+		size_t volatile vspsize = spsize;
+		G * volatile vnewg = newg;
+
+		getcontext(&vnewg->context);
+		vnewg->context.uc_stack.ss_sp = vsp;
 #ifdef MAKECONTEXT_STACK_TOP
-	newg->context.uc_stack.ss_sp += spsize;
+		vnewg->context.uc_stack.ss_sp += vspsize;
 #endif
-	newg->context.uc_stack.ss_size = spsize;
-	makecontext(&newg->context, kickoff, 0);
+		vnewg->context.uc_stack.ss_size = vspsize;
+		makecontext(&vnewg->context, kickoff, 0);
 
-	newprocreadylocked(newg);
-	schedunlock();
+		newprocreadylocked(vnewg);
+		schedunlock();
 
-	return newg;
-//printf(" goid=%d\n", newg->goid);
+		return vnewg;
+	}
 }
 
 // Put on gfree list.  Sched must be locked.