Fix pr6293. If ptr is NULL, no operation is preformed.

llvm-svn: 96154

2 files changed, 9 insertions, 0 deletions

diff --git a/clang/lib/Checker/MallocChecker.cpp b/clang/lib/Checker/MallocChecker.cpp
index 3be2e0299bb..4ff98642e1c 100644
--- a/clang/lib/Checker/MallocChecker.cpp
+++ b/clang/lib/Checker/MallocChecker.cpp
@@ -172,6 +172,11 @@ void MallocChecker::FreeMem(CheckerContext &C, const CallExpr *CE) {
 const GRState *MallocChecker::FreeMemAux(CheckerContext &C, const CallExpr *CE,
                                          const GRState *state) {
   SVal ArgVal = state->getSVal(CE->getArg(0));
+
+  // If ptr is NULL, no operation is preformed.
+  if (ArgVal.isZeroConstant())
+    return state;
+
   SymbolRef Sym = ArgVal.getAsLocSymbol();
   assert(Sym);
 
diff --git a/clang/test/Analysis/malloc.c b/clang/test/Analysis/malloc.c
index 518ab82ff11..3cce1b0d2ef 100644
--- a/clang/test/Analysis/malloc.c
+++ b/clang/test/Analysis/malloc.c
@@ -57,3 +57,7 @@ void pr6069() {
   char *buf = doit2();
   free(buf);
 }
+
+void pr6293() {
+  free(0);
+}