зеркало из https://github.com/microsoft/clang-1.git
Added transfer function support for ReturnStmt to support detecting leaks
involving objects that are returned but have an excessive reference count. git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@49861 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Ted Kremenek
Родитель
165b954fb2
Коммит
4fd8897f81
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@ -26,6 +26,15 @@
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using namespace clang;
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//===----------------------------------------------------------------------===//
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// Utility functions.
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//===----------------------------------------------------------------------===//
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static inline Selector GetUnarySelector(const char* name, ASTContext& Ctx) {
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IdentifierInfo* II = &Ctx.Idents.get(name);
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return Ctx.Selectors.getSelector(0, &II);
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}
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//===----------------------------------------------------------------------===//
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// Symbolic Evaluation of Reference Counting Logic
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//===----------------------------------------------------------------------===//
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@ -461,28 +470,35 @@ namespace {
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namespace {
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class VISIBILITY_HIDDEN RefVal {
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unsigned Data;
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public:
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RefVal(unsigned K, unsigned D) : Data((D << 3) | K) {
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assert ((K & ~0x7) == 0x0);
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}
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enum Kind {
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Owned = 0, // Owning reference.
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NotOwned, // Reference is not owned by still valid (not freed).
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Released, // Object has been released.
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ReturnedOwned, // Returned object passes ownership to caller.
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ReturnedNotOwned, // Return object does not pass ownership to caller.
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ErrorUseAfterRelease, // Object used after released.
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ErrorReleaseNotOwned, // Release of an object that was not owned.
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ErrorLeak // A memory leak due to excessive reference counts.
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};
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RefVal(unsigned K) : Data(K) {
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assert ((K & ~0x7) == 0x0);
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}
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private:
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Kind kind;
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unsigned Cnt;
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RefVal(Kind k, unsigned cnt) : kind(k), Cnt(cnt) {}
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RefVal(Kind k) : kind(k), Cnt(0) {}
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public:
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enum Kind { Owned = 0, NotOwned = 1, Released = 2,
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ErrorUseAfterRelease = 3, ErrorReleaseNotOwned = 4,
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ErrorLeak = 5 };
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Kind getKind() const { return kind; }
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Kind getKind() const { return (Kind) (Data & 0x7); }
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unsigned getCount() const { return Cnt; }
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unsigned getCount() const {
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assert (getKind() == Owned || getKind() == NotOwned);
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return Data >> 3;
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}
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// Useful predicates.
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static bool isError(Kind k) { return k >= ErrorUseAfterRelease; }
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@ -496,6 +512,21 @@ public:
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return getKind() == NotOwned;
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}
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bool isReturnedOwned() const {
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return getKind() == ReturnedOwned;
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}
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bool isReturnedNotOwned() const {
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return getKind() == ReturnedNotOwned;
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}
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bool isNonLeakError() const {
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Kind k = getKind();
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return isError(k) && !isLeak(k);
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}
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// State creation: normal state.
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static RefVal makeOwned(unsigned Count = 0) {
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return RefVal(Owned, Count);
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}
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@ -504,13 +535,31 @@ public:
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return RefVal(NotOwned, Count);
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}
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static RefVal makeReturnedOwned(unsigned Count) {
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return RefVal(ReturnedOwned, Count);
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}
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static RefVal makeReturnedNotOwned() {
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return RefVal(ReturnedNotOwned);
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}
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// State creation: errors.
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static RefVal makeLeak() { return RefVal(ErrorLeak); }
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static RefVal makeReleased() { return RefVal(Released); }
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static RefVal makeUseAfterRelease() { return RefVal(ErrorUseAfterRelease); }
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static RefVal makeReleaseNotOwned() { return RefVal(ErrorReleaseNotOwned); }
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bool operator==(const RefVal& X) const { return Data == X.Data; }
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void Profile(llvm::FoldingSetNodeID& ID) const { ID.AddInteger(Data); }
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// Comparison, profiling, and pretty-printing.
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bool operator==(const RefVal& X) const {
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return kind == X.kind && Cnt == X.Cnt;
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}
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void Profile(llvm::FoldingSetNodeID& ID) const {
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ID.AddInteger((unsigned) kind);
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ID.AddInteger(Cnt);
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}
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void print(std::ostream& Out) const;
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};
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@ -526,7 +575,21 @@ void RefVal::print(std::ostream& Out) const {
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}
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case NotOwned: {
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Out << "Not-Owned";
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Out << "NotOwned";
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unsigned cnt = getCount();
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if (cnt) Out << " (+ " << cnt << ")";
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break;
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}
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case ReturnedOwned: {
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Out << "ReturnedOwned";
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unsigned cnt = getCount();
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if (cnt) Out << " (+ " << cnt << ")";
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break;
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}
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case ReturnedNotOwned: {
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Out << "ReturnedNotOwned";
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unsigned cnt = getCount();
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if (cnt) Out << " (+ " << cnt << ")";
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break;
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@ -554,11 +617,6 @@ void RefVal::print(std::ostream& Out) const {
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// Transfer functions.
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//===----------------------------------------------------------------------===//
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static inline Selector GetUnarySelector(const char* name, ASTContext& Ctx) {
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IdentifierInfo* II = &Ctx.Idents.get(name);
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return Ctx.Selectors.getSelector(0, &II);
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}
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class VISIBILITY_HIDDEN CFRefCount : public GRSimpleVals {
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// Type definitions.
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@ -670,6 +728,14 @@ public:
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virtual void EvalEndPath(GRExprEngine& Engine,
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GREndPathNodeBuilder<ValueState>& Builder);
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// Return statements.
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virtual void EvalReturn(ExplodedNodeSet<ValueState>& Dst,
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GRExprEngine& Engine,
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GRStmtNodeBuilder<ValueState>& Builder,
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ReturnStmt* S,
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ExplodedNode<ValueState>* Pred);
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// Error iterators.
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typedef UseAfterReleasesTy::iterator use_after_iterator;
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@ -1008,7 +1074,8 @@ ValueState* CFRefCount::HandleSymbolDeath(ValueStateManager& VMgr,
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ValueState* St, SymbolID sid,
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RefVal V, bool& hasLeak) {
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hasLeak = V.isOwned() || V.isNotOwned() && V.getCount() > 0;
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hasLeak = V.isOwned() ||
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((V.isNotOwned() || V.isReturnedOwned()) && V.getCount() > 0);
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if (!hasLeak)
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return NukeBinding(VMgr, St, sid);
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@ -1043,6 +1110,66 @@ void CFRefCount::EvalEndPath(GRExprEngine& Eng,
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Leaks.push_back(std::make_pair(*I, N));
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}
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// Return statements.
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void CFRefCount::EvalReturn(ExplodedNodeSet<ValueState>& Dst,
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GRExprEngine& Eng,
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GRStmtNodeBuilder<ValueState>& Builder,
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ReturnStmt* S,
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ExplodedNode<ValueState>* Pred) {
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Expr* RetE = S->getRetValue();
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if (!RetE) return;
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ValueStateManager& StateMgr = Eng.getStateManager();
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ValueState* St = Builder.GetState(Pred);
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RVal V = StateMgr.GetRVal(St, RetE);
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if (!isa<lval::SymbolVal>(V))
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return;
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// Get the reference count binding (if any).
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SymbolID Sym = cast<lval::SymbolVal>(V).getSymbol();
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RefBindings B = GetRefBindings(*St);
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RefBindings::TreeTy* T = B.SlimFind(Sym);
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if (!T)
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return;
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// Change the reference count.
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RefVal X = T->getValue().second;
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switch (X.getKind()) {
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case RefVal::Owned: {
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unsigned cnt = X.getCount();
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X = RefVal::makeReturnedOwned(cnt);
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break;
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}
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case RefVal::NotOwned: {
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unsigned cnt = X.getCount();
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X = cnt ? RefVal::makeReturnedOwned(cnt - 1)
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: RefVal::makeReturnedNotOwned();
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break;
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}
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default:
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// None of the error states should be possible at this point.
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// A symbol could not have been leaked (yet) if we are returning it
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// (and thus it is still live), and the other errors are hard errors.
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assert(false);
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return;
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}
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// Update the binding.
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ValueState StImpl = *St;
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StImpl.CheckerState = RefBFactory.Add(B, Sym, X).getRoot();
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Builder.MakeNode(Dst, S, Pred, StateMgr.getPersistentState(StImpl));
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}
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CFRefCount::RefBindings CFRefCount::Update(RefBindings B, SymbolID sym,
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RefVal V, ArgEffect E,
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@ -1091,16 +1218,16 @@ CFRefCount::RefBindings CFRefCount::Update(RefBindings B, SymbolID sym,
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assert (false);
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case RefVal::Owned: {
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signed Count = ((signed) V.getCount()) - 1;
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V = Count >= 0 ? RefVal::makeOwned(Count) : RefVal::makeReleased();
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unsigned Count = V.getCount();
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V = Count > 0 ? RefVal::makeOwned(Count - 1) : RefVal::makeReleased();
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break;
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}
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case RefVal::NotOwned: {
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signed Count = ((signed) V.getCount()) - 1;
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unsigned Count = V.getCount();
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if (Count >= 0)
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V = RefVal::makeNotOwned(Count);
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if (Count > 0)
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V = RefVal::makeNotOwned(Count - 1);
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else {
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V = RefVal::makeReleaseNotOwned();
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hasErr = V.getKind();
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