r256887 - [analyzer] Fix false warning about memory leak for QApplication::postEvent

[Anna Zaks via cfe-commits]

Author: zaks
Date: Tue Jan  5 18:32:56 2016
New Revision: 256887

URL: http://llvm.org/viewvc/llvm-project?rev=256887&view=rev
Log:
[analyzer] Fix false warning about memory leak for QApplication::postEvent

According to Qt documentation Qt takes care of memory allocated for QEvent:
http://doc.qt.io/qt-4.8/qcoreapplication.html#postEvent

A patch by Evgeniy Dushistov!

Differential Revision: http://reviews.llvm.org/D14170

Added:
    cfe/trunk/test/Analysis/Inputs/qt-simulator.h
    cfe/trunk/test/Analysis/qt_malloc.cpp
Modified:
    cfe/trunk/lib/StaticAnalyzer/Checkers/MallocChecker.cpp

Modified: cfe/trunk/lib/StaticAnalyzer/Checkers/MallocChecker.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/StaticAnalyzer/Checkers/MallocChecker.cpp?rev=256887&r1=256886&r2=256887&view=diff
==============================================================================
--- cfe/trunk/lib/StaticAnalyzer/Checkers/MallocChecker.cpp (original)
+++ cfe/trunk/lib/StaticAnalyzer/Checkers/MallocChecker.cpp Tue Jan  5 18:32:56 2016
@@ -2508,6 +2508,16 @@ bool MallocChecker::mayFreeAnyEscapedMem
     return true;
   }
 
+  if (FName == "postEvent" &&
+      FD->getQualifiedNameAsString() == "QCoreApplication::postEvent") {
+    return true;
+  }
+
+  if (FName == "postEvent" &&
+      FD->getQualifiedNameAsString() == "QCoreApplication::postEvent") {
+    return true;
+  }
+
   // Handle cases where we know a buffer's /address/ can escape.
   // Note that the above checks handle some special cases where we know that
   // even though the address escapes, it's still our responsibility to free the

Added: cfe/trunk/test/Analysis/Inputs/qt-simulator.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Analysis/Inputs/qt-simulator.h?rev=256887&view=auto
==============================================================================
--- cfe/trunk/test/Analysis/Inputs/qt-simulator.h (added)
+++ cfe/trunk/test/Analysis/Inputs/qt-simulator.h Tue Jan  5 18:32:56 2016
@@ -0,0 +1,16 @@
+#pragma clang system_header
+
+struct QObject {
+};
+
+struct QEvent {
+  enum Type { None };
+  QEvent(Type) {}
+};
+
+struct QCoreApplication : public QObject {
+  static void postEvent(QObject *receiver, QEvent *event);
+  static QCoreApplication *instance();
+};
+
+struct QApplication : public QCoreApplication {};

Added: cfe/trunk/test/Analysis/qt_malloc.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Analysis/qt_malloc.cpp?rev=256887&view=auto
==============================================================================
--- cfe/trunk/test/Analysis/qt_malloc.cpp (added)
+++ cfe/trunk/test/Analysis/qt_malloc.cpp Tue Jan  5 18:32:56 2016
@@ -0,0 +1,15 @@
+// RUN: %clang_cc1 -analyze -analyzer-checker=core,alpha.deadcode.UnreachableCode,alpha.core.CastSize,unix.Malloc,cplusplus -analyzer-store=region -verify %s
+// expected-no-diagnostics
+#include "Inputs/qt-simulator.h"
+
+void send(QObject *obj)
+{
+  QEvent *e1 = new QEvent(QEvent::None);
+  static_cast<QApplication *>(QCoreApplication::instance())->postEvent(obj, e1);
+  QEvent *e2 = new QEvent(QEvent::None);
+  QCoreApplication::instance()->postEvent(obj, e2);
+  QEvent *e3 = new QEvent(QEvent::None);
+  QCoreApplication::postEvent(obj, e3);
+  QEvent *e4 = new QEvent(QEvent::None);
+  QApplication::postEvent(obj, e4);
+}