| //= GRState.cpp - Path-Sensitive "State" for tracking values -----*- C++ -*--=// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file implements GRState and GRStateManager. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "clang/Analysis/CFG.h" |
| #include "clang/GR/PathSensitive/GRStateTrait.h" |
| #include "clang/GR/PathSensitive/GRState.h" |
| #include "clang/GR/PathSensitive/SubEngine.h" |
| #include "clang/GR/PathSensitive/TransferFuncs.h" |
| #include "llvm/Support/raw_ostream.h" |
| |
| using namespace clang; |
| using namespace ento; |
| |
| // Give the vtable for ConstraintManager somewhere to live. |
| // FIXME: Move this elsewhere. |
| ConstraintManager::~ConstraintManager() {} |
| |
| GRStateManager::~GRStateManager() { |
| for (std::vector<GRState::Printer*>::iterator I=Printers.begin(), |
| E=Printers.end(); I!=E; ++I) |
| delete *I; |
| |
| for (GDMContextsTy::iterator I=GDMContexts.begin(), E=GDMContexts.end(); |
| I!=E; ++I) |
| I->second.second(I->second.first); |
| } |
| |
| const GRState* |
| GRStateManager::RemoveDeadBindings(const GRState* state, |
| const StackFrameContext *LCtx, |
| SymbolReaper& SymReaper) { |
| |
| // This code essentially performs a "mark-and-sweep" of the VariableBindings. |
| // The roots are any Block-level exprs and Decls that our liveness algorithm |
| // tells us are live. We then see what Decls they may reference, and keep |
| // those around. This code more than likely can be made faster, and the |
| // frequency of which this method is called should be experimented with |
| // for optimum performance. |
| llvm::SmallVector<const MemRegion*, 10> RegionRoots; |
| GRState NewState = *state; |
| |
| NewState.Env = EnvMgr.RemoveDeadBindings(NewState.Env, SymReaper, |
| state, RegionRoots); |
| |
| // Clean up the store. |
| NewState.St = StoreMgr->RemoveDeadBindings(NewState.St, LCtx, |
| SymReaper, RegionRoots); |
| state = getPersistentState(NewState); |
| return ConstraintMgr->RemoveDeadBindings(state, SymReaper); |
| } |
| |
| const GRState *GRStateManager::MarshalState(const GRState *state, |
| const StackFrameContext *InitLoc) { |
| // make up an empty state for now. |
| GRState State(this, |
| EnvMgr.getInitialEnvironment(), |
| StoreMgr->getInitialStore(InitLoc), |
| GDMFactory.getEmptyMap()); |
| |
| return getPersistentState(State); |
| } |
| |
| const GRState *GRState::bindCompoundLiteral(const CompoundLiteralExpr* CL, |
| const LocationContext *LC, |
| SVal V) const { |
| Store new_store = |
| getStateManager().StoreMgr->BindCompoundLiteral(St, CL, LC, V); |
| return makeWithStore(new_store); |
| } |
| |
| const GRState *GRState::bindDecl(const VarRegion* VR, SVal IVal) const { |
| Store new_store = getStateManager().StoreMgr->BindDecl(St, VR, IVal); |
| return makeWithStore(new_store); |
| } |
| |
| const GRState *GRState::bindDeclWithNoInit(const VarRegion* VR) const { |
| Store new_store = getStateManager().StoreMgr->BindDeclWithNoInit(St, VR); |
| return makeWithStore(new_store); |
| } |
| |
| const GRState *GRState::bindLoc(Loc LV, SVal V) const { |
| GRStateManager &Mgr = getStateManager(); |
| Store new_store = Mgr.StoreMgr->Bind(St, LV, V); |
| const GRState *new_state = makeWithStore(new_store); |
| |
| const MemRegion *MR = LV.getAsRegion(); |
| if (MR) |
| return Mgr.getOwningEngine().ProcessRegionChange(new_state, MR); |
| |
| return new_state; |
| } |
| |
| const GRState *GRState::bindDefault(SVal loc, SVal V) const { |
| GRStateManager &Mgr = getStateManager(); |
| const MemRegion *R = cast<loc::MemRegionVal>(loc).getRegion(); |
| Store new_store = Mgr.StoreMgr->BindDefault(St, R, V); |
| const GRState *new_state = makeWithStore(new_store); |
| return Mgr.getOwningEngine().ProcessRegionChange(new_state, R); |
| } |
| |
| const GRState *GRState::InvalidateRegions(const MemRegion * const *Begin, |
| const MemRegion * const *End, |
| const Expr *E, unsigned Count, |
| StoreManager::InvalidatedSymbols *IS, |
| bool invalidateGlobals) const { |
| GRStateManager &Mgr = getStateManager(); |
| SubEngine &Eng = Mgr.getOwningEngine(); |
| |
| if (Eng.WantsRegionChangeUpdate(this)) { |
| StoreManager::InvalidatedRegions Regions; |
| |
| Store new_store = Mgr.StoreMgr->InvalidateRegions(St, Begin, End, |
| E, Count, IS, |
| invalidateGlobals, |
| &Regions); |
| const GRState *new_state = makeWithStore(new_store); |
| |
| return Eng.ProcessRegionChanges(new_state, |
| &Regions.front(), |
| &Regions.back()+1); |
| } |
| |
| Store new_store = Mgr.StoreMgr->InvalidateRegions(St, Begin, End, |
| E, Count, IS, |
| invalidateGlobals, |
| NULL); |
| return makeWithStore(new_store); |
| } |
| |
| const GRState *GRState::unbindLoc(Loc LV) const { |
| assert(!isa<loc::MemRegionVal>(LV) && "Use InvalidateRegion instead."); |
| |
| Store OldStore = getStore(); |
| Store NewStore = getStateManager().StoreMgr->Remove(OldStore, LV); |
| |
| if (NewStore == OldStore) |
| return this; |
| |
| return makeWithStore(NewStore); |
| } |
| |
| const GRState *GRState::EnterStackFrame(const StackFrameContext *frame) const { |
| Store new_store = getStateManager().StoreMgr->EnterStackFrame(this, frame); |
| return makeWithStore(new_store); |
| } |
| |
| SVal GRState::getSValAsScalarOrLoc(const MemRegion *R) const { |
| // We only want to do fetches from regions that we can actually bind |
| // values. For example, SymbolicRegions of type 'id<...>' cannot |
| // have direct bindings (but their can be bindings on their subregions). |
| if (!R->isBoundable()) |
| return UnknownVal(); |
| |
| if (const TypedRegion *TR = dyn_cast<TypedRegion>(R)) { |
| QualType T = TR->getValueType(); |
| if (Loc::IsLocType(T) || T->isIntegerType()) |
| return getSVal(R); |
| } |
| |
| return UnknownVal(); |
| } |
| |
| SVal GRState::getSVal(Loc location, QualType T) const { |
| SVal V = getRawSVal(cast<Loc>(location), T); |
| |
| // If 'V' is a symbolic value that is *perfectly* constrained to |
| // be a constant value, use that value instead to lessen the burden |
| // on later analysis stages (so we have less symbolic values to reason |
| // about). |
| if (!T.isNull()) { |
| if (SymbolRef sym = V.getAsSymbol()) { |
| if (const llvm::APSInt *Int = getSymVal(sym)) { |
| // FIXME: Because we don't correctly model (yet) sign-extension |
| // and truncation of symbolic values, we need to convert |
| // the integer value to the correct signedness and bitwidth. |
| // |
| // This shows up in the following: |
| // |
| // char foo(); |
| // unsigned x = foo(); |
| // if (x == 54) |
| // ... |
| // |
| // The symbolic value stored to 'x' is actually the conjured |
| // symbol for the call to foo(); the type of that symbol is 'char', |
| // not unsigned. |
| const llvm::APSInt &NewV = getBasicVals().Convert(T, *Int); |
| |
| if (isa<Loc>(V)) |
| return loc::ConcreteInt(NewV); |
| else |
| return nonloc::ConcreteInt(NewV); |
| } |
| } |
| } |
| |
| return V; |
| } |
| |
| const GRState *GRState::BindExpr(const Stmt* S, SVal V, bool Invalidate) const{ |
| Environment NewEnv = getStateManager().EnvMgr.bindExpr(Env, S, V, |
| Invalidate); |
| if (NewEnv == Env) |
| return this; |
| |
| GRState NewSt = *this; |
| NewSt.Env = NewEnv; |
| return getStateManager().getPersistentState(NewSt); |
| } |
| |
| const GRState *GRState::bindExprAndLocation(const Stmt *S, SVal location, |
| SVal V) const { |
| Environment NewEnv = |
| getStateManager().EnvMgr.bindExprAndLocation(Env, S, location, V); |
| |
| if (NewEnv == Env) |
| return this; |
| |
| GRState NewSt = *this; |
| NewSt.Env = NewEnv; |
| return getStateManager().getPersistentState(NewSt); |
| } |
| |
| const GRState *GRState::assumeInBound(DefinedOrUnknownSVal Idx, |
| DefinedOrUnknownSVal UpperBound, |
| bool Assumption) const { |
| if (Idx.isUnknown() || UpperBound.isUnknown()) |
| return this; |
| |
| // Build an expression for 0 <= Idx < UpperBound. |
| // This is the same as Idx + MIN < UpperBound + MIN, if overflow is allowed. |
| // FIXME: This should probably be part of SValBuilder. |
| GRStateManager &SM = getStateManager(); |
| SValBuilder &svalBuilder = SM.getSValBuilder(); |
| ASTContext &Ctx = svalBuilder.getContext(); |
| |
| // Get the offset: the minimum value of the array index type. |
| BasicValueFactory &BVF = svalBuilder.getBasicValueFactory(); |
| // FIXME: This should be using ValueManager::ArrayindexTy...somehow. |
| QualType indexTy = Ctx.IntTy; |
| nonloc::ConcreteInt Min(BVF.getMinValue(indexTy)); |
| |
| // Adjust the index. |
| SVal newIdx = svalBuilder.evalBinOpNN(this, BO_Add, |
| cast<NonLoc>(Idx), Min, indexTy); |
| if (newIdx.isUnknownOrUndef()) |
| return this; |
| |
| // Adjust the upper bound. |
| SVal newBound = |
| svalBuilder.evalBinOpNN(this, BO_Add, cast<NonLoc>(UpperBound), |
| Min, indexTy); |
| |
| if (newBound.isUnknownOrUndef()) |
| return this; |
| |
| // Build the actual comparison. |
| SVal inBound = svalBuilder.evalBinOpNN(this, BO_LT, |
| cast<NonLoc>(newIdx), cast<NonLoc>(newBound), |
| Ctx.IntTy); |
| if (inBound.isUnknownOrUndef()) |
| return this; |
| |
| // Finally, let the constraint manager take care of it. |
| ConstraintManager &CM = SM.getConstraintManager(); |
| return CM.assume(this, cast<DefinedSVal>(inBound), Assumption); |
| } |
| |
| const GRState* GRStateManager::getInitialState(const LocationContext *InitLoc) { |
| GRState State(this, |
| EnvMgr.getInitialEnvironment(), |
| StoreMgr->getInitialStore(InitLoc), |
| GDMFactory.getEmptyMap()); |
| |
| return getPersistentState(State); |
| } |
| |
| const GRState* GRStateManager::getPersistentState(GRState& State) { |
| |
| llvm::FoldingSetNodeID ID; |
| State.Profile(ID); |
| void* InsertPos; |
| |
| if (GRState* I = StateSet.FindNodeOrInsertPos(ID, InsertPos)) |
| return I; |
| |
| GRState* I = (GRState*) Alloc.Allocate<GRState>(); |
| new (I) GRState(State); |
| StateSet.InsertNode(I, InsertPos); |
| return I; |
| } |
| |
| const GRState* GRState::makeWithStore(Store store) const { |
| GRState NewSt = *this; |
| NewSt.St = store; |
| return getStateManager().getPersistentState(NewSt); |
| } |
| |
| //===----------------------------------------------------------------------===// |
| // State pretty-printing. |
| //===----------------------------------------------------------------------===// |
| |
| static bool IsEnvLoc(const Stmt *S) { |
| // FIXME: This is a layering violation. Should be in environment. |
| return (bool) (((uintptr_t) S) & 0x1); |
| } |
| |
| void GRState::print(llvm::raw_ostream& Out, CFG &C, const char* nl, |
| const char* sep) const { |
| // Print the store. |
| GRStateManager &Mgr = getStateManager(); |
| Mgr.getStoreManager().print(getStore(), Out, nl, sep); |
| |
| // Print Subexpression bindings. |
| bool isFirst = true; |
| |
| // FIXME: All environment printing should be moved inside Environment. |
| for (Environment::iterator I = Env.begin(), E = Env.end(); I != E; ++I) { |
| if (C.isBlkExpr(I.getKey()) || IsEnvLoc(I.getKey())) |
| continue; |
| |
| if (isFirst) { |
| Out << nl << nl << "Sub-Expressions:" << nl; |
| isFirst = false; |
| } |
| else { Out << nl; } |
| |
| Out << " (" << (void*) I.getKey() << ") "; |
| LangOptions LO; // FIXME. |
| I.getKey()->printPretty(Out, 0, PrintingPolicy(LO)); |
| Out << " : " << I.getData(); |
| } |
| |
| // Print block-expression bindings. |
| isFirst = true; |
| |
| for (Environment::iterator I = Env.begin(), E = Env.end(); I != E; ++I) { |
| if (!C.isBlkExpr(I.getKey())) |
| continue; |
| |
| if (isFirst) { |
| Out << nl << nl << "Block-level Expressions:" << nl; |
| isFirst = false; |
| } |
| else { Out << nl; } |
| |
| Out << " (" << (void*) I.getKey() << ") "; |
| LangOptions LO; // FIXME. |
| I.getKey()->printPretty(Out, 0, PrintingPolicy(LO)); |
| Out << " : " << I.getData(); |
| } |
| |
| // Print locations. |
| isFirst = true; |
| |
| for (Environment::iterator I = Env.begin(), E = Env.end(); I != E; ++I) { |
| if (!IsEnvLoc(I.getKey())) |
| continue; |
| |
| if (isFirst) { |
| Out << nl << nl << "Load/store locations:" << nl; |
| isFirst = false; |
| } |
| else { Out << nl; } |
| |
| const Stmt *S = (Stmt*) (((uintptr_t) I.getKey()) & ((uintptr_t) ~0x1)); |
| |
| Out << " (" << (void*) S << ") "; |
| LangOptions LO; // FIXME. |
| S->printPretty(Out, 0, PrintingPolicy(LO)); |
| Out << " : " << I.getData(); |
| } |
| |
| Mgr.getConstraintManager().print(this, Out, nl, sep); |
| |
| // Print checker-specific data. |
| for (std::vector<Printer*>::iterator I = Mgr.Printers.begin(), |
| E = Mgr.Printers.end(); I != E; ++I) { |
| (*I)->Print(Out, this, nl, sep); |
| } |
| } |
| |
| void GRState::printDOT(llvm::raw_ostream& Out, CFG &C) const { |
| print(Out, C, "\\l", "\\|"); |
| } |
| |
| void GRState::printStdErr(CFG &C) const { |
| print(llvm::errs(), C); |
| } |
| |
| //===----------------------------------------------------------------------===// |
| // Generic Data Map. |
| //===----------------------------------------------------------------------===// |
| |
| void* const* GRState::FindGDM(void* K) const { |
| return GDM.lookup(K); |
| } |
| |
| void* |
| GRStateManager::FindGDMContext(void* K, |
| void* (*CreateContext)(llvm::BumpPtrAllocator&), |
| void (*DeleteContext)(void*)) { |
| |
| std::pair<void*, void (*)(void*)>& p = GDMContexts[K]; |
| if (!p.first) { |
| p.first = CreateContext(Alloc); |
| p.second = DeleteContext; |
| } |
| |
| return p.first; |
| } |
| |
| const GRState* GRStateManager::addGDM(const GRState* St, void* Key, void* Data){ |
| GRState::GenericDataMap M1 = St->getGDM(); |
| GRState::GenericDataMap M2 = GDMFactory.add(M1, Key, Data); |
| |
| if (M1 == M2) |
| return St; |
| |
| GRState NewSt = *St; |
| NewSt.GDM = M2; |
| return getPersistentState(NewSt); |
| } |
| |
| const GRState *GRStateManager::removeGDM(const GRState *state, void *Key) { |
| GRState::GenericDataMap OldM = state->getGDM(); |
| GRState::GenericDataMap NewM = GDMFactory.remove(OldM, Key); |
| |
| if (NewM == OldM) |
| return state; |
| |
| GRState NewState = *state; |
| NewState.GDM = NewM; |
| return getPersistentState(NewState); |
| } |
| |
| //===----------------------------------------------------------------------===// |
| // Utility. |
| //===----------------------------------------------------------------------===// |
| |
| namespace { |
| class ScanReachableSymbols : public SubRegionMap::Visitor { |
| typedef llvm::DenseSet<const MemRegion*> VisitedRegionsTy; |
| |
| VisitedRegionsTy visited; |
| const GRState *state; |
| SymbolVisitor &visitor; |
| llvm::OwningPtr<SubRegionMap> SRM; |
| public: |
| |
| ScanReachableSymbols(const GRState *st, SymbolVisitor& v) |
| : state(st), visitor(v) {} |
| |
| bool scan(nonloc::CompoundVal val); |
| bool scan(SVal val); |
| bool scan(const MemRegion *R); |
| |
| // From SubRegionMap::Visitor. |
| bool Visit(const MemRegion* Parent, const MemRegion* SubRegion) { |
| return scan(SubRegion); |
| } |
| }; |
| } |
| |
| bool ScanReachableSymbols::scan(nonloc::CompoundVal val) { |
| for (nonloc::CompoundVal::iterator I=val.begin(), E=val.end(); I!=E; ++I) |
| if (!scan(*I)) |
| return false; |
| |
| return true; |
| } |
| |
| bool ScanReachableSymbols::scan(SVal val) { |
| if (loc::MemRegionVal *X = dyn_cast<loc::MemRegionVal>(&val)) |
| return scan(X->getRegion()); |
| |
| if (nonloc::LocAsInteger *X = dyn_cast<nonloc::LocAsInteger>(&val)) |
| return scan(X->getLoc()); |
| |
| if (SymbolRef Sym = val.getAsSymbol()) |
| return visitor.VisitSymbol(Sym); |
| |
| if (nonloc::CompoundVal *X = dyn_cast<nonloc::CompoundVal>(&val)) |
| return scan(*X); |
| |
| return true; |
| } |
| |
| bool ScanReachableSymbols::scan(const MemRegion *R) { |
| if (isa<MemSpaceRegion>(R) || visited.count(R)) |
| return true; |
| |
| visited.insert(R); |
| |
| // If this is a symbolic region, visit the symbol for the region. |
| if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R)) |
| if (!visitor.VisitSymbol(SR->getSymbol())) |
| return false; |
| |
| // If this is a subregion, also visit the parent regions. |
| if (const SubRegion *SR = dyn_cast<SubRegion>(R)) |
| if (!scan(SR->getSuperRegion())) |
| return false; |
| |
| // Now look at the binding to this region (if any). |
| if (!scan(state->getSValAsScalarOrLoc(R))) |
| return false; |
| |
| // Now look at the subregions. |
| if (!SRM.get()) |
| SRM.reset(state->getStateManager().getStoreManager(). |
| getSubRegionMap(state->getStore())); |
| |
| return SRM->iterSubRegions(R, *this); |
| } |
| |
| bool GRState::scanReachableSymbols(SVal val, SymbolVisitor& visitor) const { |
| ScanReachableSymbols S(this, visitor); |
| return S.scan(val); |
| } |
| |
| bool GRState::scanReachableSymbols(const SVal *I, const SVal *E, |
| SymbolVisitor &visitor) const { |
| ScanReachableSymbols S(this, visitor); |
| for ( ; I != E; ++I) { |
| if (!S.scan(*I)) |
| return false; |
| } |
| return true; |
| } |
| |
| bool GRState::scanReachableSymbols(const MemRegion * const *I, |
| const MemRegion * const *E, |
| SymbolVisitor &visitor) const { |
| ScanReachableSymbols S(this, visitor); |
| for ( ; I != E; ++I) { |
| if (!S.scan(*I)) |
| return false; |
| } |
| return true; |
| } |