From b62cf212b241724d5096ba13de2d688f7e4cf43f Mon Sep 17 00:00:00 2001
From: Ted Kremenek <kremenek@apple.com>
Date: Thu, 26 Apr 2012 20:54:27 +0000
Subject: [PATCH] Defensively guard against calling malloc() with a size of
 zero.

llvm-svn: 155661
---
 llvm/runtime/libprofile/CommonProfiling.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/llvm/runtime/libprofile/CommonProfiling.c b/llvm/runtime/libprofile/CommonProfiling.c
index d55f51c5b44a..13e3eb9cf7bd 100644
--- a/llvm/runtime/libprofile/CommonProfiling.c
+++ b/llvm/runtime/libprofile/CommonProfiling.c
@@ -65,6 +65,15 @@ int save_arguments(int argc, const char **argv) {
   for (Length = 0, i = 0; i != (unsigned)argc; ++i)
     Length += strlen(argv[i])+1;
 
+  // Defensively check for a zero length, even though this is unlikely
+  // to happen in practice.  This avoids calling malloc() below with a
+  // size of 0.
+  if (Length == 0) {
+    SavedArgs = 0;
+    SavedArgsLength = 0;
+    return argc;
+  }
+  
   SavedArgs = (char*)malloc(Length);
   for (Length = 0, i = 0; i != (unsigned)argc; ++i) {
     unsigned Len = strlen(argv[i]);