[analyzer] RetainCount: Fix os_returns_retained_on_zero with weird re…

…turn types.

The checker was crashing when it was trying to assume a structure
to be null or non-null so that to evaluate the effect of the annotation.

Differential Revision: https://reviews.llvm.org/D61958

llvm-svn: 360790

clang/lib/StaticAnalyzer/Checkers/RetainCountChecker/RetainCountChecker.cpp

@@ -537,6 +537,11 @@ updateOutParameters(ProgramStateRef State, const RetainSummary &Summ,
   ProgramStateRef AssumeZeroReturn = State;
 
   if (SplitNecessary) {
+    if (!CE.getResultType()->isScalarType()) {
+      // Structures cannot be assumed. This probably deserves
+      // a compiler warning for invalid annotations.
+      return {State};
+    }
     if (auto DL = L.getAs<DefinedOrUnknownSVal>()) {
       AssumeNonZeroReturn = AssumeNonZeroReturn->assume(*DL, true);
       AssumeZeroReturn = AssumeZeroReturn->assume(*DL, false);

clang/test/Analysis/osobject-retain-release.cpp

@@ -702,3 +702,16 @@ OSObject *testSuppressionForMethodsEndingWithMatching(IOService *svc,
   // returning from it at +0.
   return table; // no-warning
 }
+
+namespace weird_result {
+struct WeirdResult {
+  int x, y, z;
+};
+
+WeirdResult outParamWithWeirdResult(OS_RETURNS_RETAINED_ON_ZERO OSObject **obj);
+
+WeirdResult testOutParamWithWeirdResult() {
+  OSObject *obj;
+  return outParamWithWeirdResult(&obj); // no-warning
+}
+} // namespace weird_result