917 lines
32 KiB
C++
917 lines
32 KiB
C++
// RetainCountDiagnostics.cpp - Checks for leaks and other issues -*- C++ -*--//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This file defines diagnostics for RetainCountChecker, which implements
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// a reference count checker for Core Foundation and Cocoa on (Mac OS X).
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//
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//===----------------------------------------------------------------------===//
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#include "RetainCountDiagnostics.h"
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#include "RetainCountChecker.h"
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using namespace clang;
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using namespace ento;
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using namespace retaincountchecker;
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StringRef RefCountBug::bugTypeToName(RefCountBug::RefCountBugKind BT) {
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switch (BT) {
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case UseAfterRelease:
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return "Use-after-release";
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case ReleaseNotOwned:
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return "Bad release";
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case DeallocNotOwned:
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return "-dealloc sent to non-exclusively owned object";
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case FreeNotOwned:
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return "freeing non-exclusively owned object";
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case OverAutorelease:
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return "Object autoreleased too many times";
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case ReturnNotOwnedForOwned:
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return "Method should return an owned object";
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case LeakWithinFunction:
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return "Leak";
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case LeakAtReturn:
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return "Leak of returned object";
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}
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llvm_unreachable("Unknown RefCountBugKind");
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}
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StringRef RefCountBug::getDescription() const {
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switch (BT) {
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case UseAfterRelease:
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return "Reference-counted object is used after it is released";
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case ReleaseNotOwned:
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return "Incorrect decrement of the reference count of an object that is "
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"not owned at this point by the caller";
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case DeallocNotOwned:
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return "-dealloc sent to object that may be referenced elsewhere";
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case FreeNotOwned:
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return "'free' called on an object that may be referenced elsewhere";
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case OverAutorelease:
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return "Object autoreleased too many times";
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case ReturnNotOwnedForOwned:
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return "Object with a +0 retain count returned to caller where a +1 "
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"(owning) retain count is expected";
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case LeakWithinFunction:
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case LeakAtReturn:
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return "";
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}
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llvm_unreachable("Unknown RefCountBugKind");
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}
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RefCountBug::RefCountBug(CheckerNameRef Checker, RefCountBugKind BT)
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: BugType(Checker, bugTypeToName(BT), categories::MemoryRefCount,
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/*SuppressOnSink=*/BT == LeakWithinFunction ||
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BT == LeakAtReturn),
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BT(BT) {}
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static bool isNumericLiteralExpression(const Expr *E) {
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// FIXME: This set of cases was copied from SemaExprObjC.
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return isa<IntegerLiteral>(E) ||
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isa<CharacterLiteral>(E) ||
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isa<FloatingLiteral>(E) ||
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isa<ObjCBoolLiteralExpr>(E) ||
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isa<CXXBoolLiteralExpr>(E);
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}
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/// If type represents a pointer to CXXRecordDecl,
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/// and is not a typedef, return the decl name.
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/// Otherwise, return the serialization of type.
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static std::string getPrettyTypeName(QualType QT) {
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QualType PT = QT->getPointeeType();
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if (!PT.isNull() && !QT->getAs<TypedefType>())
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if (const auto *RD = PT->getAsCXXRecordDecl())
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return std::string(RD->getName());
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return QT.getAsString();
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}
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/// Write information about the type state change to {@code os},
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/// return whether the note should be generated.
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static bool shouldGenerateNote(llvm::raw_string_ostream &os,
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const RefVal *PrevT,
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const RefVal &CurrV,
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bool DeallocSent) {
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// Get the previous type state.
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RefVal PrevV = *PrevT;
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// Specially handle -dealloc.
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if (DeallocSent) {
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// Determine if the object's reference count was pushed to zero.
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assert(!PrevV.hasSameState(CurrV) && "The state should have changed.");
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// We may not have transitioned to 'release' if we hit an error.
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// This case is handled elsewhere.
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if (CurrV.getKind() == RefVal::Released) {
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assert(CurrV.getCombinedCounts() == 0);
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os << "Object released by directly sending the '-dealloc' message";
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return true;
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}
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}
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// Determine if the typestate has changed.
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if (!PrevV.hasSameState(CurrV))
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switch (CurrV.getKind()) {
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case RefVal::Owned:
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case RefVal::NotOwned:
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if (PrevV.getCount() == CurrV.getCount()) {
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// Did an autorelease message get sent?
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if (PrevV.getAutoreleaseCount() == CurrV.getAutoreleaseCount())
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return false;
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assert(PrevV.getAutoreleaseCount() < CurrV.getAutoreleaseCount());
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os << "Object autoreleased";
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return true;
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}
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if (PrevV.getCount() > CurrV.getCount())
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os << "Reference count decremented.";
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else
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os << "Reference count incremented.";
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if (unsigned Count = CurrV.getCount())
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os << " The object now has a +" << Count << " retain count.";
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return true;
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case RefVal::Released:
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if (CurrV.getIvarAccessHistory() ==
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RefVal::IvarAccessHistory::ReleasedAfterDirectAccess &&
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CurrV.getIvarAccessHistory() != PrevV.getIvarAccessHistory()) {
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os << "Strong instance variable relinquished. ";
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}
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os << "Object released.";
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return true;
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case RefVal::ReturnedOwned:
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// Autoreleases can be applied after marking a node ReturnedOwned.
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if (CurrV.getAutoreleaseCount())
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return false;
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os << "Object returned to caller as an owning reference (single "
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"retain count transferred to caller)";
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return true;
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case RefVal::ReturnedNotOwned:
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os << "Object returned to caller with a +0 retain count";
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return true;
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default:
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return false;
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}
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return true;
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}
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/// Finds argument index of the out paramter in the call {@code S}
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/// corresponding to the symbol {@code Sym}.
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/// If none found, returns None.
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static Optional<unsigned> findArgIdxOfSymbol(ProgramStateRef CurrSt,
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const LocationContext *LCtx,
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SymbolRef &Sym,
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Optional<CallEventRef<>> CE) {
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if (!CE)
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return None;
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for (unsigned Idx = 0; Idx < (*CE)->getNumArgs(); Idx++)
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if (const MemRegion *MR = (*CE)->getArgSVal(Idx).getAsRegion())
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if (const auto *TR = dyn_cast<TypedValueRegion>(MR))
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if (CurrSt->getSVal(MR, TR->getValueType()).getAsSymbol() == Sym)
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return Idx;
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return None;
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}
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static Optional<std::string> findMetaClassAlloc(const Expr *Callee) {
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if (const auto *ME = dyn_cast<MemberExpr>(Callee)) {
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if (ME->getMemberDecl()->getNameAsString() != "alloc")
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return None;
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const Expr *This = ME->getBase()->IgnoreParenImpCasts();
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if (const auto *DRE = dyn_cast<DeclRefExpr>(This)) {
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const ValueDecl *VD = DRE->getDecl();
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if (VD->getNameAsString() != "metaClass")
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return None;
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if (const auto *RD = dyn_cast<CXXRecordDecl>(VD->getDeclContext()))
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return RD->getNameAsString();
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}
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}
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return None;
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}
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static std::string findAllocatedObjectName(const Stmt *S, QualType QT) {
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if (const auto *CE = dyn_cast<CallExpr>(S))
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if (auto Out = findMetaClassAlloc(CE->getCallee()))
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return *Out;
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return getPrettyTypeName(QT);
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}
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static void generateDiagnosticsForCallLike(ProgramStateRef CurrSt,
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const LocationContext *LCtx,
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const RefVal &CurrV, SymbolRef &Sym,
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const Stmt *S,
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llvm::raw_string_ostream &os) {
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CallEventManager &Mgr = CurrSt->getStateManager().getCallEventManager();
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if (const CallExpr *CE = dyn_cast<CallExpr>(S)) {
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// Get the name of the callee (if it is available)
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// from the tracked SVal.
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SVal X = CurrSt->getSValAsScalarOrLoc(CE->getCallee(), LCtx);
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const FunctionDecl *FD = X.getAsFunctionDecl();
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// If failed, try to get it from AST.
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if (!FD)
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FD = dyn_cast<FunctionDecl>(CE->getCalleeDecl());
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if (const auto *MD = dyn_cast<CXXMethodDecl>(CE->getCalleeDecl())) {
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os << "Call to method '" << MD->getQualifiedNameAsString() << '\'';
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} else if (FD) {
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os << "Call to function '" << FD->getQualifiedNameAsString() << '\'';
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} else {
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os << "function call";
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}
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} else if (isa<CXXNewExpr>(S)) {
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os << "Operator 'new'";
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} else {
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assert(isa<ObjCMessageExpr>(S));
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CallEventRef<ObjCMethodCall> Call =
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Mgr.getObjCMethodCall(cast<ObjCMessageExpr>(S), CurrSt, LCtx);
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switch (Call->getMessageKind()) {
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case OCM_Message:
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os << "Method";
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break;
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case OCM_PropertyAccess:
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os << "Property";
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break;
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case OCM_Subscript:
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os << "Subscript";
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break;
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}
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}
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Optional<CallEventRef<>> CE = Mgr.getCall(S, CurrSt, LCtx);
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auto Idx = findArgIdxOfSymbol(CurrSt, LCtx, Sym, CE);
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// If index is not found, we assume that the symbol was returned.
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if (!Idx) {
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os << " returns ";
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} else {
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os << " writes ";
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}
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if (CurrV.getObjKind() == ObjKind::CF) {
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os << "a Core Foundation object of type '"
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<< Sym->getType().getAsString() << "' with a ";
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} else if (CurrV.getObjKind() == ObjKind::OS) {
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os << "an OSObject of type '" << findAllocatedObjectName(S, Sym->getType())
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<< "' with a ";
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} else if (CurrV.getObjKind() == ObjKind::Generalized) {
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os << "an object of type '" << Sym->getType().getAsString()
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<< "' with a ";
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} else {
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assert(CurrV.getObjKind() == ObjKind::ObjC);
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QualType T = Sym->getType();
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if (!isa<ObjCObjectPointerType>(T)) {
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os << "an Objective-C object with a ";
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} else {
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const ObjCObjectPointerType *PT = cast<ObjCObjectPointerType>(T);
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os << "an instance of " << PT->getPointeeType().getAsString()
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<< " with a ";
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}
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}
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if (CurrV.isOwned()) {
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os << "+1 retain count";
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} else {
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assert(CurrV.isNotOwned());
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os << "+0 retain count";
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}
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if (Idx) {
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os << " into an out parameter '";
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const ParmVarDecl *PVD = (*CE)->parameters()[*Idx];
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PVD->getNameForDiagnostic(os, PVD->getASTContext().getPrintingPolicy(),
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/*Qualified=*/false);
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os << "'";
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QualType RT = (*CE)->getResultType();
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if (!RT.isNull() && !RT->isVoidType()) {
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SVal RV = (*CE)->getReturnValue();
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if (CurrSt->isNull(RV).isConstrainedTrue()) {
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os << " (assuming the call returns zero)";
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} else if (CurrSt->isNonNull(RV).isConstrainedTrue()) {
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os << " (assuming the call returns non-zero)";
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}
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}
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}
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}
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namespace clang {
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namespace ento {
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namespace retaincountchecker {
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class RefCountReportVisitor : public BugReporterVisitor {
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protected:
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SymbolRef Sym;
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public:
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RefCountReportVisitor(SymbolRef sym) : Sym(sym) {}
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void Profile(llvm::FoldingSetNodeID &ID) const override {
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static int x = 0;
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ID.AddPointer(&x);
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ID.AddPointer(Sym);
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}
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PathDiagnosticPieceRef VisitNode(const ExplodedNode *N,
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BugReporterContext &BRC,
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PathSensitiveBugReport &BR) override;
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PathDiagnosticPieceRef getEndPath(BugReporterContext &BRC,
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const ExplodedNode *N,
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PathSensitiveBugReport &BR) override;
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};
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class RefLeakReportVisitor : public RefCountReportVisitor {
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public:
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RefLeakReportVisitor(SymbolRef sym) : RefCountReportVisitor(sym) {}
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PathDiagnosticPieceRef getEndPath(BugReporterContext &BRC,
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const ExplodedNode *N,
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PathSensitiveBugReport &BR) override;
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};
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} // end namespace retaincountchecker
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} // end namespace ento
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} // end namespace clang
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/// Find the first node with the parent stack frame.
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static const ExplodedNode *getCalleeNode(const ExplodedNode *Pred) {
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const StackFrameContext *SC = Pred->getStackFrame();
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if (SC->inTopFrame())
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return nullptr;
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const StackFrameContext *PC = SC->getParent()->getStackFrame();
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if (!PC)
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return nullptr;
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const ExplodedNode *N = Pred;
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while (N && N->getStackFrame() != PC) {
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N = N->getFirstPred();
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}
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return N;
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}
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/// Insert a diagnostic piece at function exit
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/// if a function parameter is annotated as "os_consumed",
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/// but it does not actually consume the reference.
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static std::shared_ptr<PathDiagnosticEventPiece>
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annotateConsumedSummaryMismatch(const ExplodedNode *N,
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CallExitBegin &CallExitLoc,
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const SourceManager &SM,
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CallEventManager &CEMgr) {
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const ExplodedNode *CN = getCalleeNode(N);
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if (!CN)
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return nullptr;
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CallEventRef<> Call = CEMgr.getCaller(N->getStackFrame(), N->getState());
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std::string sbuf;
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llvm::raw_string_ostream os(sbuf);
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ArrayRef<const ParmVarDecl *> Parameters = Call->parameters();
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for (unsigned I=0; I < Call->getNumArgs() && I < Parameters.size(); ++I) {
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const ParmVarDecl *PVD = Parameters[I];
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if (!PVD->hasAttr<OSConsumedAttr>())
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continue;
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if (SymbolRef SR = Call->getArgSVal(I).getAsLocSymbol()) {
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const RefVal *CountBeforeCall = getRefBinding(CN->getState(), SR);
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const RefVal *CountAtExit = getRefBinding(N->getState(), SR);
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if (!CountBeforeCall || !CountAtExit)
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continue;
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unsigned CountBefore = CountBeforeCall->getCount();
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unsigned CountAfter = CountAtExit->getCount();
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bool AsExpected = CountBefore > 0 && CountAfter == CountBefore - 1;
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if (!AsExpected) {
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os << "Parameter '";
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PVD->getNameForDiagnostic(os, PVD->getASTContext().getPrintingPolicy(),
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/*Qualified=*/false);
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os << "' is marked as consuming, but the function did not consume "
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<< "the reference\n";
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}
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}
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}
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if (os.str().empty())
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return nullptr;
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PathDiagnosticLocation L = PathDiagnosticLocation::create(CallExitLoc, SM);
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return std::make_shared<PathDiagnosticEventPiece>(L, os.str());
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}
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/// Annotate the parameter at the analysis entry point.
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static std::shared_ptr<PathDiagnosticEventPiece>
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annotateStartParameter(const ExplodedNode *N, SymbolRef Sym,
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const SourceManager &SM) {
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auto PP = N->getLocationAs<BlockEdge>();
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if (!PP)
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return nullptr;
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const CFGBlock *Src = PP->getSrc();
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const RefVal *CurrT = getRefBinding(N->getState(), Sym);
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if (&Src->getParent()->getEntry() != Src || !CurrT ||
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getRefBinding(N->getFirstPred()->getState(), Sym))
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return nullptr;
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const auto *VR = cast<VarRegion>(cast<SymbolRegionValue>(Sym)->getRegion());
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const auto *PVD = cast<ParmVarDecl>(VR->getDecl());
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PathDiagnosticLocation L = PathDiagnosticLocation(PVD, SM);
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std::string s;
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llvm::raw_string_ostream os(s);
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os << "Parameter '" << PVD->getDeclName() << "' starts at +";
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if (CurrT->getCount() == 1) {
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os << "1, as it is marked as consuming";
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} else {
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assert(CurrT->getCount() == 0);
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os << "0";
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}
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return std::make_shared<PathDiagnosticEventPiece>(L, os.str());
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}
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PathDiagnosticPieceRef
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RefCountReportVisitor::VisitNode(const ExplodedNode *N, BugReporterContext &BRC,
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PathSensitiveBugReport &BR) {
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const auto &BT = static_cast<const RefCountBug&>(BR.getBugType());
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bool IsFreeUnowned = BT.getBugType() == RefCountBug::FreeNotOwned ||
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BT.getBugType() == RefCountBug::DeallocNotOwned;
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const SourceManager &SM = BRC.getSourceManager();
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CallEventManager &CEMgr = BRC.getStateManager().getCallEventManager();
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if (auto CE = N->getLocationAs<CallExitBegin>())
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if (auto PD = annotateConsumedSummaryMismatch(N, *CE, SM, CEMgr))
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return PD;
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if (auto PD = annotateStartParameter(N, Sym, SM))
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return PD;
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// FIXME: We will eventually need to handle non-statement-based events
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// (__attribute__((cleanup))).
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if (!N->getLocation().getAs<StmtPoint>())
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return nullptr;
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// Check if the type state has changed.
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const ExplodedNode *PrevNode = N->getFirstPred();
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ProgramStateRef PrevSt = PrevNode->getState();
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ProgramStateRef CurrSt = N->getState();
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const LocationContext *LCtx = N->getLocationContext();
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const RefVal* CurrT = getRefBinding(CurrSt, Sym);
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if (!CurrT)
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return nullptr;
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const RefVal &CurrV = *CurrT;
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const RefVal *PrevT = getRefBinding(PrevSt, Sym);
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// Create a string buffer to constain all the useful things we want
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// to tell the user.
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std::string sbuf;
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llvm::raw_string_ostream os(sbuf);
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if (PrevT && IsFreeUnowned && CurrV.isNotOwned() && PrevT->isOwned()) {
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os << "Object is now not exclusively owned";
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auto Pos = PathDiagnosticLocation::create(N->getLocation(), SM);
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return std::make_shared<PathDiagnosticEventPiece>(Pos, os.str());
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}
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// This is the allocation site since the previous node had no bindings
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// for this symbol.
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if (!PrevT) {
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const Stmt *S = N->getLocation().castAs<StmtPoint>().getStmt();
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|
|
if (isa<ObjCIvarRefExpr>(S) &&
|
|
isSynthesizedAccessor(LCtx->getStackFrame())) {
|
|
S = LCtx->getStackFrame()->getCallSite();
|
|
}
|
|
|
|
if (isa<ObjCArrayLiteral>(S)) {
|
|
os << "NSArray literal is an object with a +0 retain count";
|
|
} else if (isa<ObjCDictionaryLiteral>(S)) {
|
|
os << "NSDictionary literal is an object with a +0 retain count";
|
|
} else if (const ObjCBoxedExpr *BL = dyn_cast<ObjCBoxedExpr>(S)) {
|
|
if (isNumericLiteralExpression(BL->getSubExpr()))
|
|
os << "NSNumber literal is an object with a +0 retain count";
|
|
else {
|
|
const ObjCInterfaceDecl *BoxClass = nullptr;
|
|
if (const ObjCMethodDecl *Method = BL->getBoxingMethod())
|
|
BoxClass = Method->getClassInterface();
|
|
|
|
// We should always be able to find the boxing class interface,
|
|
// but consider this future-proofing.
|
|
if (BoxClass) {
|
|
os << *BoxClass << " b";
|
|
} else {
|
|
os << "B";
|
|
}
|
|
|
|
os << "oxed expression produces an object with a +0 retain count";
|
|
}
|
|
} else if (isa<ObjCIvarRefExpr>(S)) {
|
|
os << "Object loaded from instance variable";
|
|
} else {
|
|
generateDiagnosticsForCallLike(CurrSt, LCtx, CurrV, Sym, S, os);
|
|
}
|
|
|
|
PathDiagnosticLocation Pos(S, SM, N->getLocationContext());
|
|
return std::make_shared<PathDiagnosticEventPiece>(Pos, os.str());
|
|
}
|
|
|
|
// Gather up the effects that were performed on the object at this
|
|
// program point
|
|
bool DeallocSent = false;
|
|
|
|
const ProgramPointTag *Tag = N->getLocation().getTag();
|
|
|
|
if (Tag == &RetainCountChecker::getCastFailTag()) {
|
|
os << "Assuming dynamic cast returns null due to type mismatch";
|
|
}
|
|
|
|
if (Tag == &RetainCountChecker::getDeallocSentTag()) {
|
|
// We only have summaries attached to nodes after evaluating CallExpr and
|
|
// ObjCMessageExprs.
|
|
const Stmt *S = N->getLocation().castAs<StmtPoint>().getStmt();
|
|
|
|
if (const CallExpr *CE = dyn_cast<CallExpr>(S)) {
|
|
// Iterate through the parameter expressions and see if the symbol
|
|
// was ever passed as an argument.
|
|
unsigned i = 0;
|
|
|
|
for (auto AI=CE->arg_begin(), AE=CE->arg_end(); AI!=AE; ++AI, ++i) {
|
|
|
|
// Retrieve the value of the argument. Is it the symbol
|
|
// we are interested in?
|
|
if (CurrSt->getSValAsScalarOrLoc(*AI, LCtx).getAsLocSymbol() != Sym)
|
|
continue;
|
|
|
|
// We have an argument. Get the effect!
|
|
DeallocSent = true;
|
|
}
|
|
} else if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(S)) {
|
|
if (const Expr *receiver = ME->getInstanceReceiver()) {
|
|
if (CurrSt->getSValAsScalarOrLoc(receiver, LCtx)
|
|
.getAsLocSymbol() == Sym) {
|
|
// The symbol we are tracking is the receiver.
|
|
DeallocSent = true;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
if (!shouldGenerateNote(os, PrevT, CurrV, DeallocSent))
|
|
return nullptr;
|
|
|
|
if (os.str().empty())
|
|
return nullptr; // We have nothing to say!
|
|
|
|
const Stmt *S = N->getLocation().castAs<StmtPoint>().getStmt();
|
|
PathDiagnosticLocation Pos(S, BRC.getSourceManager(),
|
|
N->getLocationContext());
|
|
auto P = std::make_shared<PathDiagnosticEventPiece>(Pos, os.str());
|
|
|
|
// Add the range by scanning the children of the statement for any bindings
|
|
// to Sym.
|
|
for (const Stmt *Child : S->children())
|
|
if (const Expr *Exp = dyn_cast_or_null<Expr>(Child))
|
|
if (CurrSt->getSValAsScalarOrLoc(Exp, LCtx).getAsLocSymbol() == Sym) {
|
|
P->addRange(Exp->getSourceRange());
|
|
break;
|
|
}
|
|
|
|
return std::move(P);
|
|
}
|
|
|
|
static Optional<std::string> describeRegion(const MemRegion *MR) {
|
|
if (const auto *VR = dyn_cast_or_null<VarRegion>(MR))
|
|
return std::string(VR->getDecl()->getName());
|
|
// Once we support more storage locations for bindings,
|
|
// this would need to be improved.
|
|
return None;
|
|
}
|
|
|
|
namespace {
|
|
// Find the first node in the current function context that referred to the
|
|
// tracked symbol and the memory location that value was stored to. Note, the
|
|
// value is only reported if the allocation occurred in the same function as
|
|
// the leak. The function can also return a location context, which should be
|
|
// treated as interesting.
|
|
struct AllocationInfo {
|
|
const ExplodedNode* N;
|
|
const MemRegion *R;
|
|
const LocationContext *InterestingMethodContext;
|
|
AllocationInfo(const ExplodedNode *InN,
|
|
const MemRegion *InR,
|
|
const LocationContext *InInterestingMethodContext) :
|
|
N(InN), R(InR), InterestingMethodContext(InInterestingMethodContext) {}
|
|
};
|
|
} // end anonymous namespace
|
|
|
|
static AllocationInfo GetAllocationSite(ProgramStateManager &StateMgr,
|
|
const ExplodedNode *N, SymbolRef Sym) {
|
|
const ExplodedNode *AllocationNode = N;
|
|
const ExplodedNode *AllocationNodeInCurrentOrParentContext = N;
|
|
const MemRegion *FirstBinding = nullptr;
|
|
const LocationContext *LeakContext = N->getLocationContext();
|
|
|
|
// The location context of the init method called on the leaked object, if
|
|
// available.
|
|
const LocationContext *InitMethodContext = nullptr;
|
|
|
|
while (N) {
|
|
ProgramStateRef St = N->getState();
|
|
const LocationContext *NContext = N->getLocationContext();
|
|
|
|
if (!getRefBinding(St, Sym))
|
|
break;
|
|
|
|
StoreManager::FindUniqueBinding FB(Sym);
|
|
StateMgr.iterBindings(St, FB);
|
|
|
|
if (FB) {
|
|
const MemRegion *R = FB.getRegion();
|
|
// Do not show local variables belonging to a function other than
|
|
// where the error is reported.
|
|
if (auto MR = dyn_cast<StackSpaceRegion>(R->getMemorySpace()))
|
|
if (MR->getStackFrame() == LeakContext->getStackFrame())
|
|
FirstBinding = R;
|
|
}
|
|
|
|
// AllocationNode is the last node in which the symbol was tracked.
|
|
AllocationNode = N;
|
|
|
|
// AllocationNodeInCurrentContext, is the last node in the current or
|
|
// parent context in which the symbol was tracked.
|
|
//
|
|
// Note that the allocation site might be in the parent context. For example,
|
|
// the case where an allocation happens in a block that captures a reference
|
|
// to it and that reference is overwritten/dropped by another call to
|
|
// the block.
|
|
if (NContext == LeakContext || NContext->isParentOf(LeakContext))
|
|
AllocationNodeInCurrentOrParentContext = N;
|
|
|
|
// Find the last init that was called on the given symbol and store the
|
|
// init method's location context.
|
|
if (!InitMethodContext)
|
|
if (auto CEP = N->getLocation().getAs<CallEnter>()) {
|
|
const Stmt *CE = CEP->getCallExpr();
|
|
if (const auto *ME = dyn_cast_or_null<ObjCMessageExpr>(CE)) {
|
|
const Stmt *RecExpr = ME->getInstanceReceiver();
|
|
if (RecExpr) {
|
|
SVal RecV = St->getSVal(RecExpr, NContext);
|
|
if (ME->getMethodFamily() == OMF_init && RecV.getAsSymbol() == Sym)
|
|
InitMethodContext = CEP->getCalleeContext();
|
|
}
|
|
}
|
|
}
|
|
|
|
N = N->getFirstPred();
|
|
}
|
|
|
|
// If we are reporting a leak of the object that was allocated with alloc,
|
|
// mark its init method as interesting.
|
|
const LocationContext *InterestingMethodContext = nullptr;
|
|
if (InitMethodContext) {
|
|
const ProgramPoint AllocPP = AllocationNode->getLocation();
|
|
if (Optional<StmtPoint> SP = AllocPP.getAs<StmtPoint>())
|
|
if (const ObjCMessageExpr *ME = SP->getStmtAs<ObjCMessageExpr>())
|
|
if (ME->getMethodFamily() == OMF_alloc)
|
|
InterestingMethodContext = InitMethodContext;
|
|
}
|
|
|
|
// If allocation happened in a function different from the leak node context,
|
|
// do not report the binding.
|
|
assert(N && "Could not find allocation node");
|
|
|
|
if (AllocationNodeInCurrentOrParentContext &&
|
|
AllocationNodeInCurrentOrParentContext->getLocationContext() !=
|
|
LeakContext)
|
|
FirstBinding = nullptr;
|
|
|
|
return AllocationInfo(AllocationNodeInCurrentOrParentContext, FirstBinding,
|
|
InterestingMethodContext);
|
|
}
|
|
|
|
PathDiagnosticPieceRef
|
|
RefCountReportVisitor::getEndPath(BugReporterContext &BRC,
|
|
const ExplodedNode *EndN,
|
|
PathSensitiveBugReport &BR) {
|
|
BR.markInteresting(Sym);
|
|
return BugReporterVisitor::getDefaultEndPath(BRC, EndN, BR);
|
|
}
|
|
|
|
PathDiagnosticPieceRef
|
|
RefLeakReportVisitor::getEndPath(BugReporterContext &BRC,
|
|
const ExplodedNode *EndN,
|
|
PathSensitiveBugReport &BR) {
|
|
|
|
// Tell the BugReporterContext to report cases when the tracked symbol is
|
|
// assigned to different variables, etc.
|
|
BR.markInteresting(Sym);
|
|
|
|
// We are reporting a leak. Walk up the graph to get to the first node where
|
|
// the symbol appeared, and also get the first VarDecl that tracked object
|
|
// is stored to.
|
|
AllocationInfo AllocI = GetAllocationSite(BRC.getStateManager(), EndN, Sym);
|
|
|
|
const MemRegion* FirstBinding = AllocI.R;
|
|
BR.markInteresting(AllocI.InterestingMethodContext);
|
|
|
|
PathDiagnosticLocation L = cast<RefLeakReport>(BR).getEndOfPath();
|
|
|
|
std::string sbuf;
|
|
llvm::raw_string_ostream os(sbuf);
|
|
|
|
os << "Object leaked: ";
|
|
|
|
Optional<std::string> RegionDescription = describeRegion(FirstBinding);
|
|
if (RegionDescription) {
|
|
os << "object allocated and stored into '" << *RegionDescription << '\'';
|
|
} else {
|
|
os << "allocated object of type '" << getPrettyTypeName(Sym->getType())
|
|
<< "'";
|
|
}
|
|
|
|
// Get the retain count.
|
|
const RefVal* RV = getRefBinding(EndN->getState(), Sym);
|
|
assert(RV);
|
|
|
|
if (RV->getKind() == RefVal::ErrorLeakReturned) {
|
|
// FIXME: Per comments in rdar://6320065, "create" only applies to CF
|
|
// objects. Only "copy", "alloc", "retain" and "new" transfer ownership
|
|
// to the caller for NS objects.
|
|
const Decl *D = &EndN->getCodeDecl();
|
|
|
|
os << (isa<ObjCMethodDecl>(D) ? " is returned from a method "
|
|
: " is returned from a function ");
|
|
|
|
if (D->hasAttr<CFReturnsNotRetainedAttr>()) {
|
|
os << "that is annotated as CF_RETURNS_NOT_RETAINED";
|
|
} else if (D->hasAttr<NSReturnsNotRetainedAttr>()) {
|
|
os << "that is annotated as NS_RETURNS_NOT_RETAINED";
|
|
} else if (D->hasAttr<OSReturnsNotRetainedAttr>()) {
|
|
os << "that is annotated as OS_RETURNS_NOT_RETAINED";
|
|
} else {
|
|
if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D)) {
|
|
if (BRC.getASTContext().getLangOpts().ObjCAutoRefCount) {
|
|
os << "managed by Automatic Reference Counting";
|
|
} else {
|
|
os << "whose name ('" << MD->getSelector().getAsString()
|
|
<< "') does not start with "
|
|
"'copy', 'mutableCopy', 'alloc' or 'new'."
|
|
" This violates the naming convention rules"
|
|
" given in the Memory Management Guide for Cocoa";
|
|
}
|
|
} else {
|
|
const FunctionDecl *FD = cast<FunctionDecl>(D);
|
|
ObjKind K = RV->getObjKind();
|
|
if (K == ObjKind::ObjC || K == ObjKind::CF) {
|
|
os << "whose name ('" << *FD
|
|
<< "') does not contain 'Copy' or 'Create'. This violates the "
|
|
"naming"
|
|
" convention rules given in the Memory Management Guide for "
|
|
"Core"
|
|
" Foundation";
|
|
} else if (RV->getObjKind() == ObjKind::OS) {
|
|
std::string FuncName = FD->getNameAsString();
|
|
os << "whose name ('" << FuncName
|
|
<< "') starts with '" << StringRef(FuncName).substr(0, 3) << "'";
|
|
}
|
|
}
|
|
}
|
|
} else {
|
|
os << " is not referenced later in this execution path and has a retain "
|
|
"count of +" << RV->getCount();
|
|
}
|
|
|
|
return std::make_shared<PathDiagnosticEventPiece>(L, os.str());
|
|
}
|
|
|
|
RefCountReport::RefCountReport(const RefCountBug &D, const LangOptions &LOpts,
|
|
ExplodedNode *n, SymbolRef sym, bool isLeak)
|
|
: PathSensitiveBugReport(D, D.getDescription(), n), Sym(sym),
|
|
isLeak(isLeak) {
|
|
if (!isLeak)
|
|
addVisitor(std::make_unique<RefCountReportVisitor>(sym));
|
|
}
|
|
|
|
RefCountReport::RefCountReport(const RefCountBug &D, const LangOptions &LOpts,
|
|
ExplodedNode *n, SymbolRef sym,
|
|
StringRef endText)
|
|
: PathSensitiveBugReport(D, D.getDescription(), endText, n) {
|
|
|
|
addVisitor(std::make_unique<RefCountReportVisitor>(sym));
|
|
}
|
|
|
|
void RefLeakReport::deriveParamLocation(CheckerContext &Ctx, SymbolRef sym) {
|
|
const SourceManager& SMgr = Ctx.getSourceManager();
|
|
|
|
if (!sym->getOriginRegion())
|
|
return;
|
|
|
|
auto *Region = dyn_cast<DeclRegion>(sym->getOriginRegion());
|
|
if (Region) {
|
|
const Decl *PDecl = Region->getDecl();
|
|
if (PDecl && isa<ParmVarDecl>(PDecl)) {
|
|
PathDiagnosticLocation ParamLocation =
|
|
PathDiagnosticLocation::create(PDecl, SMgr);
|
|
Location = ParamLocation;
|
|
UniqueingLocation = ParamLocation;
|
|
UniqueingDecl = Ctx.getLocationContext()->getDecl();
|
|
}
|
|
}
|
|
}
|
|
|
|
void RefLeakReport::deriveAllocLocation(CheckerContext &Ctx,
|
|
SymbolRef sym) {
|
|
// Most bug reports are cached at the location where they occurred.
|
|
// With leaks, we want to unique them by the location where they were
|
|
// allocated, and only report a single path. To do this, we need to find
|
|
// the allocation site of a piece of tracked memory, which we do via a
|
|
// call to GetAllocationSite. This will walk the ExplodedGraph backwards.
|
|
// Note that this is *not* the trimmed graph; we are guaranteed, however,
|
|
// that all ancestor nodes that represent the allocation site have the
|
|
// same SourceLocation.
|
|
const ExplodedNode *AllocNode = nullptr;
|
|
|
|
const SourceManager& SMgr = Ctx.getSourceManager();
|
|
|
|
AllocationInfo AllocI =
|
|
GetAllocationSite(Ctx.getStateManager(), getErrorNode(), sym);
|
|
|
|
AllocNode = AllocI.N;
|
|
AllocBinding = AllocI.R;
|
|
markInteresting(AllocI.InterestingMethodContext);
|
|
|
|
// Get the SourceLocation for the allocation site.
|
|
// FIXME: This will crash the analyzer if an allocation comes from an
|
|
// implicit call (ex: a destructor call).
|
|
// (Currently there are no such allocations in Cocoa, though.)
|
|
AllocStmt = AllocNode->getStmtForDiagnostics();
|
|
|
|
if (!AllocStmt) {
|
|
AllocBinding = nullptr;
|
|
return;
|
|
}
|
|
|
|
PathDiagnosticLocation AllocLocation =
|
|
PathDiagnosticLocation::createBegin(AllocStmt, SMgr,
|
|
AllocNode->getLocationContext());
|
|
Location = AllocLocation;
|
|
|
|
// Set uniqieing info, which will be used for unique the bug reports. The
|
|
// leaks should be uniqued on the allocation site.
|
|
UniqueingLocation = AllocLocation;
|
|
UniqueingDecl = AllocNode->getLocationContext()->getDecl();
|
|
}
|
|
|
|
void RefLeakReport::createDescription(CheckerContext &Ctx) {
|
|
assert(Location.isValid() && UniqueingDecl && UniqueingLocation.isValid());
|
|
Description.clear();
|
|
llvm::raw_string_ostream os(Description);
|
|
os << "Potential leak of an object";
|
|
|
|
Optional<std::string> RegionDescription = describeRegion(AllocBinding);
|
|
if (RegionDescription) {
|
|
os << " stored into '" << *RegionDescription << '\'';
|
|
} else {
|
|
|
|
// If we can't figure out the name, just supply the type information.
|
|
os << " of type '" << getPrettyTypeName(Sym->getType()) << "'";
|
|
}
|
|
}
|
|
|
|
RefLeakReport::RefLeakReport(const RefCountBug &D, const LangOptions &LOpts,
|
|
ExplodedNode *n, SymbolRef sym,
|
|
CheckerContext &Ctx)
|
|
: RefCountReport(D, LOpts, n, sym, /*isLeak=*/true) {
|
|
|
|
deriveAllocLocation(Ctx, sym);
|
|
if (!AllocBinding)
|
|
deriveParamLocation(Ctx, sym);
|
|
|
|
createDescription(Ctx);
|
|
|
|
addVisitor(std::make_unique<RefLeakReportVisitor>(sym));
|
|
}
|