[analyzer] Stop tracking the objects with attribute cleanup in the RetainCountChecker.

This suppresses false positive leaks. We stop tracking a value if it is assigned to a variable declared with a cleanup attribute.

llvm-svn: 190835

clang/lib/StaticAnalyzer/Checkers/RetainCountChecker.cpp

@@ -3356,6 +3356,16 @@ void RetainCountChecker::checkBind(SVal loc, SVal val, const Stmt *S,
     }
   }
 
+  // If we are storing the value into an auto function scope variable annotated
+  // with (__attribute__((cleanup))), stop tracking the value to avoid leak
+  // false positives.
+  if (const VarRegion *LVR = dyn_cast_or_null<VarRegion>(loc.getAsRegion())) {
+    const VarDecl *VD = LVR->getDecl();
+    if (VD->getAttr<CleanupAttr>()) {
+      escapes = true;
+    }
+  }
+
   // If our store can represent the binding and we aren't storing to something
   // that doesn't have local storage then just return and have the simulation
   // state continue as is.

clang/test/Analysis/retain-release.m

@@ -2022,6 +2022,20 @@ void rdar13783514(xpc_connection_t connection) {
   xpc_connection_set_finalizer_f(connection, releaseAfterXPC);
 } // no-warning
 
+// Do not report leaks when object is cleaned up with __attribute__((cleanup ..)).
+inline static void cleanupFunction(void *tp) {
+    CFTypeRef x = *(CFTypeRef *)tp;
+    if (x) {
+        CFRelease(x);
+    }
+}
+#define ADDCLEANUP __attribute__((cleanup(cleanupFunction)))
+void foo() {
+  ADDCLEANUP CFStringRef myString;
+  myString = CFStringCreateWithCString(0, "hello world", kCFStringEncodingUTF8);
+  ADDCLEANUP CFStringRef myString2 = 
+    CFStringCreateWithCString(0, "hello world", kCFStringEncodingUTF8);
+}
 
 // CHECK:  <key>diagnostics</key>
 // CHECK-NEXT:  <array>