Defensively guard against calling malloc() with a size of zero.

llvm-svn: 155661

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]);