lib/Checker/NSAutoreleasePoolChecker.cpp

   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 it's 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 "clang/GR/BugReporter/BugReporter.h"
  19 #include "clang/GR/PathSensitive/GRExprEngine.h"
  20 #include "clang/GR/PathSensitive/CheckerVisitor.h"
  21 #include "BasicObjCFoundationChecks.h"
  22 #include "clang/AST/DeclObjC.h"
  23 #include "clang/AST/Decl.h"
  24
  25 using namespace clang;
  26
  27 namespace {
  28 class NSAutoreleasePoolChecker
  29   : public CheckerVisitor<NSAutoreleasePoolChecker> {
  30
  31   Selector releaseS;
  32
  33 public:
  34     NSAutoreleasePoolChecker(Selector release_s) : releaseS(release_s) {}
  35
  36   static void *getTag() {
  37     static int x = 0;
  38     return &x;
  39   }
  40
  41   void PreVisitObjCMessageExpr(CheckerContext &C, const ObjCMessageExpr *ME);
  42 };
  43
  44 } // end anonymous namespace
  45
  46
  47 void clang::RegisterNSAutoreleasePoolChecks(GRExprEngine &Eng) {
  48   ASTContext &Ctx = Eng.getContext();
  49   if (Ctx.getLangOptions().getGCMode() != LangOptions::NonGC) {
  50     Eng.registerCheck(new NSAutoreleasePoolChecker(GetNullarySelector("release",
  51                                                                       Ctx)));
  52   }
  53 }
  54
  55 void
  56 NSAutoreleasePoolChecker::PreVisitObjCMessageExpr(CheckerContext &C,
  57                                                   const ObjCMessageExpr *ME) {
  58
  59   const Expr *receiver = ME->getInstanceReceiver();
  60   if (!receiver)
  61     return;
  62
  63   // FIXME: Enhance with value-tracking information instead of consulting
  64   // the type of the expression.
  65   const ObjCObjectPointerType* PT =
  66     receiver->getType()->getAs<ObjCObjectPointerType>();
  67
  68   if (!PT)
  69     return;
  70   const ObjCInterfaceDecl* OD = PT->getInterfaceDecl();
  71   if (!OD)
  72     return;
  73   if (!OD->getIdentifier()->getName().equals("NSAutoreleasePool"))
  74     return;
  75
  76   // Sending 'release' message?
  77   if (ME->getSelector() != releaseS)
  78     return;
  79
  80   SourceRange R = ME->getSourceRange();
  81
  82   C.getBugReporter().EmitBasicReport("Use -drain instead of -release",
  83     "API Upgrade (Apple)",
  84     "Use -drain instead of -release when using NSAutoreleasePool "
  85     "and garbage collection", ME->getLocStart(), &R, 1);
  86 }