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