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      1 //=- NSAutoreleasePoolChecker.cpp --------------------------------*- C++ -*-==//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 //
     10 //  This file defines a NSAutoreleasePoolChecker, a small checker that warns
     11 //  about subpar uses of NSAutoreleasePool.  Note that while the check itself
     12 //  (in its current form) could be written as a flow-insensitive check, in
     13 //  can be potentially enhanced in the future with flow-sensitive information.
     14 //  It is also a good example of the CheckerVisitor interface.
     15 //
     16 //===----------------------------------------------------------------------===//
     17 
     18 #include "ClangSACheckers.h"
     19 #include "clang/AST/Decl.h"
     20 #include "clang/AST/DeclObjC.h"
     21 #include "clang/StaticAnalyzer/Core/BugReporter/BugReporter.h"
     22 #include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
     23 #include "clang/StaticAnalyzer/Core/Checker.h"
     24 #include "clang/StaticAnalyzer/Core/CheckerManager.h"
     25 #include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h"
     26 #include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
     27 #include "clang/StaticAnalyzer/Core/PathSensitive/ExprEngine.h"
     28 
     29 using namespace clang;
     30 using namespace ento;
     31 
     32 namespace {
     33 class NSAutoreleasePoolChecker
     34   : public Checker<check::PreObjCMessage> {
     35   mutable std::unique_ptr<BugType> BT;
     36   mutable Selector releaseS;
     37 
     38 public:
     39   void checkPreObjCMessage(const ObjCMethodCall &msg, CheckerContext &C) const;
     40 };
     41 
     42 } // end anonymous namespace
     43 
     44 void NSAutoreleasePoolChecker::checkPreObjCMessage(const ObjCMethodCall &msg,
     45                                                    CheckerContext &C) const {
     46   if (!msg.isInstanceMessage())
     47     return;
     48 
     49   const ObjCInterfaceDecl *OD = msg.getReceiverInterface();
     50   if (!OD)
     51     return;
     52   if (!OD->getIdentifier()->isStr("NSAutoreleasePool"))
     53     return;
     54 
     55   if (releaseS.isNull())
     56     releaseS = GetNullarySelector("release", C.getASTContext());
     57   // Sending 'release' message?
     58   if (msg.getSelector() != releaseS)
     59     return;
     60 
     61   if (!BT)
     62     BT.reset(new BugType(this, "Use -drain instead of -release",
     63                          "API Upgrade (Apple)"));
     64 
     65   ExplodedNode *N = C.generateNonFatalErrorNode();
     66   if (!N) {
     67     assert(0);
     68     return;
     69   }
     70 
     71   auto Report = llvm::make_unique<BugReport>(
     72       *BT, "Use -drain instead of -release when using NSAutoreleasePool and "
     73            "garbage collection", N);
     74   Report->addRange(msg.getSourceRange());
     75   C.emitReport(std::move(Report));
     76 }
     77 
     78 void ento::registerNSAutoreleasePoolChecker(CheckerManager &mgr) {
     79   if (mgr.getLangOpts().getGC() != LangOptions::NonGC)
     80     mgr.registerChecker<NSAutoreleasePoolChecker>();
     81 }
     82