258 lines
8.5 KiB
C++
258 lines
8.5 KiB
C++
//==- CheckObjCDealloc.cpp - Check ObjC -dealloc implementation --*- C++ -*-==//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file defines a CheckObjCDealloc, a checker that
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// analyzes an Objective-C class's implementation to determine if it
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// correctly implements -dealloc.
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//
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//===----------------------------------------------------------------------===//
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#include "clang/Analysis/LocalCheckers.h"
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#include "clang/Analysis/PathDiagnostic.h"
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#include "clang/Analysis/PathSensitive/BugReporter.h"
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#include "clang/AST/ExprObjC.h"
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#include "clang/AST/Expr.h"
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#include "clang/AST/DeclObjC.h"
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#include "clang/Basic/LangOptions.h"
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#include "llvm/Support/raw_ostream.h"
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using namespace clang;
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static bool scan_dealloc(Stmt* S, Selector Dealloc) {
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if (ObjCMessageExpr* ME = dyn_cast<ObjCMessageExpr>(S))
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if (ME->getSelector() == Dealloc)
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if(ME->getReceiver())
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if (Expr* Receiver = ME->getReceiver()->IgnoreParenCasts())
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return isa<ObjCSuperExpr>(Receiver);
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// Recurse to children.
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for (Stmt::child_iterator I = S->child_begin(), E= S->child_end(); I!=E; ++I)
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if (*I && scan_dealloc(*I, Dealloc))
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return true;
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return false;
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}
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static bool scan_ivar_release(Stmt* S, ObjCIvarDecl* ID,
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const ObjCPropertyDecl* PD,
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Selector Release,
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IdentifierInfo* SelfII,
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ASTContext& Ctx) {
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// [mMyIvar release]
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if (ObjCMessageExpr* ME = dyn_cast<ObjCMessageExpr>(S))
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if (ME->getSelector() == Release)
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if(ME->getReceiver())
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if (Expr* Receiver = ME->getReceiver()->IgnoreParenCasts())
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if (ObjCIvarRefExpr* E = dyn_cast<ObjCIvarRefExpr>(Receiver))
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if (E->getDecl() == ID)
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return true;
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// [self setMyIvar:nil];
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if (ObjCMessageExpr* ME = dyn_cast<ObjCMessageExpr>(S))
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if(ME->getReceiver())
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if (Expr* Receiver = ME->getReceiver()->IgnoreParenCasts())
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if (DeclRefExpr* E = dyn_cast<DeclRefExpr>(Receiver))
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if (E->getDecl()->getIdentifier() == SelfII)
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if (ME->getMethodDecl() == PD->getSetterMethodDecl() &&
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ME->getNumArgs() == 1 &&
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ME->getArg(0)->isNullPointerConstant(Ctx))
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return true;
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// self.myIvar = nil;
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if (BinaryOperator* BO = dyn_cast<BinaryOperator>(S))
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if (BO->isAssignmentOp())
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if(ObjCPropertyRefExpr* PRE =
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dyn_cast<ObjCPropertyRefExpr>(BO->getLHS()->IgnoreParenCasts()))
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if(PRE->getProperty() == PD)
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if(BO->getRHS()->isNullPointerConstant(Ctx)) {
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// This is only a 'release' if the property kind is not
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// 'assign'.
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return PD->getSetterKind() != ObjCPropertyDecl::Assign;;
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}
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// Recurse to children.
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for (Stmt::child_iterator I = S->child_begin(), E= S->child_end(); I!=E; ++I)
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if (*I && scan_ivar_release(*I, ID, PD, Release, SelfII, Ctx))
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return true;
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return false;
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}
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void clang::CheckObjCDealloc(ObjCImplementationDecl* D,
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const LangOptions& LOpts, BugReporter& BR) {
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assert (LOpts.getGCMode() != LangOptions::GCOnly);
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ASTContext& Ctx = BR.getContext();
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ObjCInterfaceDecl* ID = D->getClassInterface();
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// Does the class contain any ivars that are pointers (or id<...>)?
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// If not, skip the check entirely.
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// NOTE: This is motivated by PR 2517:
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// http://llvm.org/bugs/show_bug.cgi?id=2517
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bool containsPointerIvar = false;
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for (ObjCInterfaceDecl::ivar_iterator I=ID->ivar_begin(), E=ID->ivar_end();
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I!=E; ++I) {
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ObjCIvarDecl* ID = *I;
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QualType T = ID->getType();
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if (!Ctx.isObjCObjectPointerType(T) ||
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ID->getAttr<IBOutletAttr>()) // Skip IBOutlets.
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continue;
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containsPointerIvar = true;
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break;
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}
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if (!containsPointerIvar)
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return;
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// Determine if the class subclasses NSObject.
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IdentifierInfo* NSObjectII = &Ctx.Idents.get("NSObject");
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IdentifierInfo* SenTestCaseII = &Ctx.Idents.get("SenTestCase");
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for ( ; ID ; ID = ID->getSuperClass()) {
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IdentifierInfo *II = ID->getIdentifier();
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if (II == NSObjectII)
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break;
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// FIXME: For now, ignore classes that subclass SenTestCase, as these don't
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// need to implement -dealloc. They implement tear down in another way,
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// which we should try and catch later.
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// http://llvm.org/bugs/show_bug.cgi?id=3187
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if (II == SenTestCaseII)
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return;
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}
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if (!ID)
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return;
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// Get the "dealloc" selector.
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IdentifierInfo* II = &Ctx.Idents.get("dealloc");
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Selector S = Ctx.Selectors.getSelector(0, &II);
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ObjCMethodDecl* MD = 0;
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// Scan the instance methods for "dealloc".
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for (ObjCImplementationDecl::instmeth_iterator I = D->instmeth_begin(Ctx),
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E = D->instmeth_end(Ctx); I!=E; ++I) {
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if ((*I)->getSelector() == S) {
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MD = *I;
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break;
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}
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}
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if (!MD) { // No dealloc found.
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const char* name = LOpts.getGCMode() == LangOptions::NonGC
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? "missing -dealloc"
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: "missing -dealloc (Hybrid MM, non-GC)";
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std::string buf;
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llvm::raw_string_ostream os(buf);
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os << "Objective-C class '" << D->getNameAsString()
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<< "' lacks a 'dealloc' instance method";
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BR.EmitBasicReport(name, os.str().c_str(), D->getLocStart());
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return;
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}
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// dealloc found. Scan for missing [super dealloc].
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if (MD->getBody(Ctx) && !scan_dealloc(MD->getBody(Ctx), S)) {
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const char* name = LOpts.getGCMode() == LangOptions::NonGC
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? "missing [super dealloc]"
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: "missing [super dealloc] (Hybrid MM, non-GC)";
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std::string buf;
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llvm::raw_string_ostream os(buf);
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os << "The 'dealloc' instance method in Objective-C class '"
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<< D->getNameAsString()
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<< "' does not send a 'dealloc' message to its super class"
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" (missing [super dealloc])";
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BR.EmitBasicReport(name, os.str().c_str(), D->getLocStart());
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return;
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}
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// Get the "release" selector.
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IdentifierInfo* RII = &Ctx.Idents.get("release");
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Selector RS = Ctx.Selectors.getSelector(0, &RII);
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// Get the "self" identifier
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IdentifierInfo* SelfII = &Ctx.Idents.get("self");
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// Scan for missing and extra releases of ivars used by implementations
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// of synthesized properties
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for (ObjCImplementationDecl::propimpl_iterator I = D->propimpl_begin(Ctx),
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E = D->propimpl_end(Ctx); I!=E; ++I) {
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// We can only check the synthesized properties
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if((*I)->getPropertyImplementation() != ObjCPropertyImplDecl::Synthesize)
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continue;
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ObjCIvarDecl* ID = (*I)->getPropertyIvarDecl();
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if (!ID)
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continue;
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QualType T = ID->getType();
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if (!Ctx.isObjCObjectPointerType(T)) // Skip non-pointer ivars
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continue;
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const ObjCPropertyDecl* PD = (*I)->getPropertyDecl();
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if(!PD)
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continue;
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// ivars cannot be set via read-only properties, so we'll skip them
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if(PD->isReadOnly())
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continue;
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// ivar must be released if and only if the kind of setter was not 'assign'
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bool requiresRelease = PD->getSetterKind() != ObjCPropertyDecl::Assign;
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if(scan_ivar_release(MD->getBody(Ctx), ID, PD, RS, SelfII, Ctx)
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!= requiresRelease) {
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const char *name;
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const char* category = "Memory (Core Foundation/Objective-C)";
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std::string buf;
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llvm::raw_string_ostream os(buf);
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if(requiresRelease) {
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name = LOpts.getGCMode() == LangOptions::NonGC
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? "missing ivar release (leak)"
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: "missing ivar release (Hybrid MM, non-GC)";
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os << "The '" << ID->getNameAsString()
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<< "' instance variable was retained by a synthesized property but "
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"wasn't released in 'dealloc'";
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} else {
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name = LOpts.getGCMode() == LangOptions::NonGC
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? "extra ivar release (use-after-release)"
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: "extra ivar release (Hybrid MM, non-GC)";
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os << "The '" << ID->getNameAsString()
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<< "' instance variable was not retained by a synthesized property "
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"but was released in 'dealloc'";
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}
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BR.EmitBasicReport(name, category,
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os.str().c_str(), (*I)->getLocation());
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}
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}
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}
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