From 3c8b7515f41f5b636a437a808a77fcad959b6831 Mon Sep 17 00:00:00 2001
From: Nico Weber <thakis@chromium.org>
Date: Thu, 23 May 2013 18:20:22 -0700
Subject: [PATCH] Don't use va_start() with reference parameters, it's
 undefined behavior.

Should fix issue #584.
---
 src/ninja.cc | 4 ++--
 src/util.cc  | 5 ++++-
 src/util.h   | 2 +-
 3 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/src/ninja.cc b/src/ninja.cc
index b4797ed..bb3abe1 100644
--- a/src/ninja.cc
+++ b/src/ninja.cc
@@ -385,7 +385,7 @@ int ToolTargets(Globals* globals, int argc, char* argv[]) {
       return ToolTargetsList(globals->state);
     } else {
       const char* suggestion =
-          SpellcheckString(mode, "rule", "depth", "all", NULL);
+          SpellcheckString(mode.c_str(), "rule", "depth", "all", NULL);
       if (suggestion) {
         Error("unknown target tool mode '%s', did you mean '%s'?",
               mode.c_str(), suggestion);
@@ -628,7 +628,7 @@ bool DebugEnable(const string& name, Globals* globals) {
     return true;
   } else {
     const char* suggestion =
-        SpellcheckString(name, "stats", "explain", NULL);
+        SpellcheckString(name.c_str(), "stats", "explain", NULL);
     if (suggestion) {
       Error("unknown debug setting '%s', did you mean '%s'?",
             name.c_str(), suggestion);
diff --git a/src/util.cc b/src/util.cc
index fa72dd2..b9c2c0d 100644
--- a/src/util.cc
+++ b/src/util.cc
@@ -234,13 +234,16 @@ const char* SpellcheckStringV(const string& text,
   return result;
 }
 
-const char* SpellcheckString(const string& text, ...) {
+const char* SpellcheckString(const char* text, ...) {
+  // Note: This takes a const char* instead of a string& because using
+  // va_start() with a reference parameter is undefined behavior.
   va_list ap;
   va_start(ap, text);
   vector<const char*> words;
   const char* word;
   while ((word = va_arg(ap, const char*)))
     words.push_back(word);
+  va_end(ap);
   return SpellcheckStringV(text, words);
 }
 
diff --git a/src/util.h b/src/util.h
index 9740565..6788410 100644
--- a/src/util.h
+++ b/src/util.h
@@ -59,7 +59,7 @@ const char* SpellcheckStringV(const string& text,
                               const vector<const char*>& words);
 
 /// Like SpellcheckStringV, but takes a NULL-terminated list.
-const char* SpellcheckString(const string& text, ...);
+const char* SpellcheckString(const char* text, ...);
 
 /// Removes all Ansi escape codes (http://www.termsys.demon.co.uk/vtansi.htm).
 string StripAnsiEscapeCodes(const string& in);
-- 
2.7.4