Author: baloghadamsoftware Date: Tue Dec 4 02:22:28 2018 New Revision: 348244
URL: http://llvm.org/viewvc/llvm-project?rev=348244&view=rev Log: [Analyzer] Iterator Checkers - Use the region of the topmost base class for iterators stored in a region If an iterator is represented by a derived C++ class but its comparison operator is for its base the iterator checkers cannot recognize the iterators compared. This results in false positives in very straightforward cases (range error when dereferencing an iterator after disclosing that it is equal to the past-the-end iterator). To overcome this problem we always use the region of the topmost base class for iterators stored in a region. A new method called getMostDerivedObjectRegion() was added to the MemRegion class to get this region. Differential Revision: https://reviews.llvm.org/D54466 Modified: cfe/trunk/include/clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h cfe/trunk/lib/StaticAnalyzer/Checkers/IteratorChecker.cpp cfe/trunk/lib/StaticAnalyzer/Core/MemRegion.cpp cfe/trunk/test/Analysis/iterator-range.cpp Modified: cfe/trunk/include/clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h?rev=348244&r1=348243&r2=348244&view=diff ============================================================================== --- cfe/trunk/include/clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h (original) +++ cfe/trunk/include/clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h Tue Dec 4 02:22:28 2018 @@ -118,6 +118,10 @@ public: const MemRegion *getBaseRegion() const; + /// Recursively retrieve the region of the most derived class instance of + /// regions of C++ base class instances. + const MemRegion *getMostDerivedObjectRegion() const; + /// Check if the region is a subregion of the given region. /// Each region is a subregion of itself. virtual bool isSubRegionOf(const MemRegion *R) const; Modified: cfe/trunk/lib/StaticAnalyzer/Checkers/IteratorChecker.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/StaticAnalyzer/Checkers/IteratorChecker.cpp?rev=348244&r1=348243&r2=348244&view=diff ============================================================================== --- cfe/trunk/lib/StaticAnalyzer/Checkers/IteratorChecker.cpp (original) +++ cfe/trunk/lib/StaticAnalyzer/Checkers/IteratorChecker.cpp Tue Dec 4 02:22:28 2018 @@ -1089,9 +1089,7 @@ void IteratorChecker::verifyRandomIncrOr void IteratorChecker::verifyMatch(CheckerContext &C, const SVal &Iter, const MemRegion *Cont) const { // Verify match between a container and the container of an iterator - while (const auto *CBOR = Cont->getAs<CXXBaseObjectRegion>()) { - Cont = CBOR->getSuperRegion(); - } + Cont = Cont->getMostDerivedObjectRegion(); auto State = C.getState(); const auto *Pos = getIteratorPosition(State, Iter); @@ -1125,9 +1123,7 @@ void IteratorChecker::handleBegin(Checke if (!ContReg) return; - while (const auto *CBOR = ContReg->getAs<CXXBaseObjectRegion>()) { - ContReg = CBOR->getSuperRegion(); - } + ContReg = ContReg->getMostDerivedObjectRegion(); // If the container already has a begin symbol then use it. Otherwise first // create a new one. @@ -1151,9 +1147,7 @@ void IteratorChecker::handleEnd(CheckerC if (!ContReg) return; - while (const auto *CBOR = ContReg->getAs<CXXBaseObjectRegion>()) { - ContReg = CBOR->getSuperRegion(); - } + ContReg = ContReg->getMostDerivedObjectRegion(); // If the container already has an end symbol then use it. Otherwise first // create a new one. @@ -1174,9 +1168,7 @@ void IteratorChecker::handleEnd(CheckerC void IteratorChecker::assignToContainer(CheckerContext &C, const Expr *CE, const SVal &RetVal, const MemRegion *Cont) const { - while (const auto *CBOR = Cont->getAs<CXXBaseObjectRegion>()) { - Cont = CBOR->getSuperRegion(); - } + Cont = Cont->getMostDerivedObjectRegion(); auto State = C.getState(); auto &SymMgr = C.getSymbolManager(); @@ -1194,9 +1186,7 @@ void IteratorChecker::handleAssign(Check if (!ContReg) return; - while (const auto *CBOR = ContReg->getAs<CXXBaseObjectRegion>()) { - ContReg = CBOR->getSuperRegion(); - } + ContReg = ContReg->getMostDerivedObjectRegion(); // Assignment of a new value to a container always invalidates all its // iterators @@ -1211,9 +1201,7 @@ void IteratorChecker::handleAssign(Check if (!OldCont.isUndef()) { const auto *OldContReg = OldCont.getAsRegion(); if (OldContReg) { - while (const auto *CBOR = OldContReg->getAs<CXXBaseObjectRegion>()) { - OldContReg = CBOR->getSuperRegion(); - } + OldContReg = OldContReg->getMostDerivedObjectRegion(); const auto OldCData = getContainerData(State, OldContReg); if (OldCData) { if (const auto OldEndSym = OldCData->getEnd()) { @@ -1273,9 +1261,7 @@ void IteratorChecker::handleClear(Checke if (!ContReg) return; - while (const auto *CBOR = ContReg->getAs<CXXBaseObjectRegion>()) { - ContReg = CBOR->getSuperRegion(); - } + ContReg = ContReg->getMostDerivedObjectRegion(); // The clear() operation invalidates all the iterators, except the past-end // iterators of list-like containers @@ -1302,9 +1288,7 @@ void IteratorChecker::handlePushBack(Che if (!ContReg) return; - while (const auto *CBOR = ContReg->getAs<CXXBaseObjectRegion>()) { - ContReg = CBOR->getSuperRegion(); - } + ContReg = ContReg->getMostDerivedObjectRegion(); // For deque-like containers invalidate all iterator positions auto State = C.getState(); @@ -1341,9 +1325,7 @@ void IteratorChecker::handlePopBack(Chec if (!ContReg) return; - while (const auto *CBOR = ContReg->getAs<CXXBaseObjectRegion>()) { - ContReg = CBOR->getSuperRegion(); - } + ContReg = ContReg->getMostDerivedObjectRegion(); auto State = C.getState(); const auto CData = getContainerData(State, ContReg); @@ -1381,9 +1363,7 @@ void IteratorChecker::handlePushFront(Ch if (!ContReg) return; - while (const auto *CBOR = ContReg->getAs<CXXBaseObjectRegion>()) { - ContReg = CBOR->getSuperRegion(); - } + ContReg = ContReg->getMostDerivedObjectRegion(); // For deque-like containers invalidate all iterator positions auto State = C.getState(); @@ -1416,9 +1396,7 @@ void IteratorChecker::handlePopFront(Che if (!ContReg) return; - while (const auto *CBOR = ContReg->getAs<CXXBaseObjectRegion>()) { - ContReg = CBOR->getSuperRegion(); - } + ContReg = ContReg->getMostDerivedObjectRegion(); auto State = C.getState(); const auto CData = getContainerData(State, ContReg); @@ -2015,7 +1993,8 @@ ProgramStateRef setContainerData(Program const IteratorPosition *getIteratorPosition(ProgramStateRef State, const SVal &Val) { - if (const auto Reg = Val.getAsRegion()) { + if (auto Reg = Val.getAsRegion()) { + Reg = Reg->getMostDerivedObjectRegion(); return State->get<IteratorRegionMap>(Reg); } else if (const auto Sym = Val.getAsSymbol()) { return State->get<IteratorSymbolMap>(Sym); @@ -2028,7 +2007,8 @@ const IteratorPosition *getIteratorPosit const IteratorPosition *getIteratorPosition(ProgramStateRef State, RegionOrSymbol RegOrSym) { if (RegOrSym.is<const MemRegion *>()) { - return State->get<IteratorRegionMap>(RegOrSym.get<const MemRegion *>()); + auto Reg = RegOrSym.get<const MemRegion *>()->getMostDerivedObjectRegion(); + return State->get<IteratorRegionMap>(Reg); } else if (RegOrSym.is<SymbolRef>()) { return State->get<IteratorSymbolMap>(RegOrSym.get<SymbolRef>()); } @@ -2037,7 +2017,8 @@ const IteratorPosition *getIteratorPosit ProgramStateRef setIteratorPosition(ProgramStateRef State, const SVal &Val, const IteratorPosition &Pos) { - if (const auto Reg = Val.getAsRegion()) { + if (auto Reg = Val.getAsRegion()) { + Reg = Reg->getMostDerivedObjectRegion(); return State->set<IteratorRegionMap>(Reg, Pos); } else if (const auto Sym = Val.getAsSymbol()) { return State->set<IteratorSymbolMap>(Sym, Pos); @@ -2051,8 +2032,8 @@ ProgramStateRef setIteratorPosition(Prog RegionOrSymbol RegOrSym, const IteratorPosition &Pos) { if (RegOrSym.is<const MemRegion *>()) { - return State->set<IteratorRegionMap>(RegOrSym.get<const MemRegion *>(), - Pos); + auto Reg = RegOrSym.get<const MemRegion *>()->getMostDerivedObjectRegion(); + return State->set<IteratorRegionMap>(Reg, Pos); } else if (RegOrSym.is<SymbolRef>()) { return State->set<IteratorSymbolMap>(RegOrSym.get<SymbolRef>(), Pos); } @@ -2060,7 +2041,8 @@ ProgramStateRef setIteratorPosition(Prog } ProgramStateRef removeIteratorPosition(ProgramStateRef State, const SVal &Val) { - if (const auto Reg = Val.getAsRegion()) { + if (auto Reg = Val.getAsRegion()) { + Reg = Reg->getMostDerivedObjectRegion(); return State->remove<IteratorRegionMap>(Reg); } else if (const auto Sym = Val.getAsSymbol()) { return State->remove<IteratorSymbolMap>(Sym); Modified: cfe/trunk/lib/StaticAnalyzer/Core/MemRegion.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/StaticAnalyzer/Core/MemRegion.cpp?rev=348244&r1=348243&r2=348244&view=diff ============================================================================== --- cfe/trunk/lib/StaticAnalyzer/Core/MemRegion.cpp (original) +++ cfe/trunk/lib/StaticAnalyzer/Core/MemRegion.cpp Tue Dec 4 02:22:28 2018 @@ -1175,6 +1175,15 @@ const MemRegion *MemRegion::getBaseRegio return R; } +// getgetMostDerivedObjectRegion gets the region of the root class of a C++ +// class hierarchy. +const MemRegion *MemRegion::getMostDerivedObjectRegion() const { + const MemRegion *R = this; + while (const auto *BR = dyn_cast<CXXBaseObjectRegion>(R)) + R = BR->getSuperRegion(); + return R; +} + bool MemRegion::isSubRegionOf(const MemRegion *) const { return false; } Modified: cfe/trunk/test/Analysis/iterator-range.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Analysis/iterator-range.cpp?rev=348244&r1=348243&r2=348244&view=diff ============================================================================== --- cfe/trunk/test/Analysis/iterator-range.cpp (original) +++ cfe/trunk/test/Analysis/iterator-range.cpp Tue Dec 4 02:22:28 2018 @@ -200,3 +200,40 @@ void bad_move_push_back(std::list<int> & ++i0; *++i0; // expected-warning{{Iterator accessed outside of its range}} } + +struct simple_iterator_base { + simple_iterator_base(); + simple_iterator_base(const simple_iterator_base& rhs); + simple_iterator_base &operator=(const simple_iterator_base& rhs); + virtual ~simple_iterator_base(); + bool friend operator==(const simple_iterator_base &lhs, + const simple_iterator_base &rhs); + bool friend operator!=(const simple_iterator_base &lhs, + const simple_iterator_base &rhs); +private: + int *ptr; +}; + +struct simple_derived_iterator: public simple_iterator_base { + int& operator*(); + int* operator->(); + simple_iterator_base &operator++(); + simple_iterator_base operator++(int); + simple_iterator_base &operator--(); + simple_iterator_base operator--(int); +}; + +struct simple_container { + typedef simple_derived_iterator iterator; + + iterator begin(); + iterator end(); +}; + +void good_derived(simple_container c) { + auto i0 = c.end(); + if (i0 != c.end()) { + clang_analyzer_warnIfReached(); + *i0; // no-warning + } +} _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits