| // BugReporterVisitors.cpp - Helpers for reporting bugs -----------*- C++ -*--// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file defines a set of BugReporter "visitors" which can be used to |
| // enhance the diagnostics reported for a bug. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "clang/AST/Expr.h" |
| #include "clang/AST/ExprObjC.h" |
| #include "clang/Analysis/PathSensitive/BugReporter.h" |
| #include "clang/Analysis/PathDiagnostic.h" |
| #include "clang/Analysis/PathSensitive/GRState.h" |
| |
| using namespace clang; |
| |
| //===----------------------------------------------------------------------===// |
| // Utility functions. |
| //===----------------------------------------------------------------------===// |
| |
| const Stmt *clang::bugreporter::GetDerefExpr(const ExplodedNode<GRState> *N) { |
| // Pattern match for a few useful cases (do something smarter later): |
| // a[0], p->f, *p |
| const Stmt *S = N->getLocationAs<PostStmt>()->getStmt(); |
| |
| if (const UnaryOperator *U = dyn_cast<UnaryOperator>(S)) { |
| if (U->getOpcode() == UnaryOperator::Deref) |
| return U->getSubExpr()->IgnoreParenCasts(); |
| } |
| else if (const MemberExpr *ME = dyn_cast<MemberExpr>(S)) { |
| return ME->getBase()->IgnoreParenCasts(); |
| } |
| else if (const ArraySubscriptExpr *AE = dyn_cast<ArraySubscriptExpr>(S)) { |
| // Retrieve the base for arrays since BasicStoreManager doesn't know how |
| // to reason about them. |
| return AE->getBase(); |
| } |
| |
| return NULL; |
| } |
| |
| const Stmt* |
| clang::bugreporter::GetReceiverExpr(const ExplodedNode<GRState> *N){ |
| const Stmt *S = N->getLocationAs<PostStmt>()->getStmt(); |
| if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(S)) |
| return ME->getReceiver(); |
| return NULL; |
| } |
| |
| const Stmt* |
| clang::bugreporter::GetDenomExpr(const ExplodedNode<GRState> *N) { |
| const Stmt *S = N->getLocationAs<PostStmt>()->getStmt(); |
| if (const BinaryOperator *BE = dyn_cast<BinaryOperator>(S)) |
| return BE->getRHS(); |
| return NULL; |
| } |
| |
| const Stmt* |
| clang::bugreporter::GetCalleeExpr(const ExplodedNode<GRState> *N) { |
| const Stmt *S = N->getLocationAs<PostStmt>()->getStmt(); |
| if (const CallExpr *CE = dyn_cast<CallExpr>(S)) |
| return CE->getCallee(); |
| return NULL; |
| } |
| |
| const Stmt* |
| clang::bugreporter::GetRetValExpr(const ExplodedNode<GRState> *N) { |
| const Stmt *S = N->getLocationAs<PostStmt>()->getStmt(); |
| if (const ReturnStmt *RS = dyn_cast<ReturnStmt>(S)) |
| return RS->getRetValue(); |
| return NULL; |
| } |
| |
| //===----------------------------------------------------------------------===// |
| // Definitions for bug reporter visitors. |
| //===----------------------------------------------------------------------===// |
| |
| namespace { |
| class VISIBILITY_HIDDEN FindLastStoreBRVisitor : public BugReporterVisitor { |
| const MemRegion *R; |
| SVal V; |
| bool satisfied; |
| const ExplodedNode<GRState> *StoreSite; |
| public: |
| FindLastStoreBRVisitor(SVal v, const MemRegion *r) |
| : R(r), V(v), satisfied(false), StoreSite(0) {} |
| |
| PathDiagnosticPiece* VisitNode(const ExplodedNode<GRState> *N, |
| const ExplodedNode<GRState> *PrevN, |
| BugReporterContext& BRC) { |
| |
| if (satisfied) |
| return NULL; |
| |
| if (!StoreSite) { |
| const ExplodedNode<GRState> *Node = N, *Last = NULL; |
| |
| for ( ; Node ; Last = Node, Node = Node->getFirstPred()) { |
| |
| if (const VarRegion *VR = dyn_cast<VarRegion>(R)) { |
| if (const PostStmt *P = Node->getLocationAs<PostStmt>()) |
| if (const DeclStmt *DS = P->getStmtAs<DeclStmt>()) |
| if (DS->getSingleDecl() == VR->getDecl()) { |
| Last = Node; |
| break; |
| } |
| } |
| |
| if (Node->getState()->getSVal(R) != V) |
| break; |
| } |
| |
| if (!Node || !Last) { |
| satisfied = true; |
| return NULL; |
| } |
| |
| StoreSite = Last; |
| } |
| |
| if (StoreSite != N) |
| return NULL; |
| |
| satisfied = true; |
| std::string sbuf; |
| llvm::raw_string_ostream os(sbuf); |
| |
| if (const PostStmt *PS = N->getLocationAs<PostStmt>()) { |
| if (const DeclStmt *DS = PS->getStmtAs<DeclStmt>()) { |
| |
| if (const VarRegion *VR = dyn_cast<VarRegion>(R)) { |
| os << "Variable '" << VR->getDecl()->getNameAsString() << "' "; |
| } |
| else |
| return NULL; |
| |
| if (isa<loc::ConcreteInt>(V)) { |
| bool b = false; |
| ASTContext &C = BRC.getASTContext(); |
| if (R->isBoundable()) { |
| if (const TypedRegion *TR = dyn_cast<TypedRegion>(R)) { |
| if (TR->getValueType(C)->isObjCObjectPointerType()) { |
| os << "initialized to nil"; |
| b = true; |
| } |
| } |
| } |
| |
| if (!b) |
| os << "initialized to a null pointer value"; |
| } |
| else if (isa<nonloc::ConcreteInt>(V)) { |
| os << "initialized to " << cast<nonloc::ConcreteInt>(V).getValue(); |
| } |
| else if (V.isUndef()) { |
| if (isa<VarRegion>(R)) { |
| const VarDecl *VD = cast<VarDecl>(DS->getSingleDecl()); |
| if (VD->getInit()) |
| os << "initialized to a garbage value"; |
| else |
| os << "declared without an initial value"; |
| } |
| } |
| } |
| } |
| |
| if (os.str().empty()) { |
| if (isa<loc::ConcreteInt>(V)) { |
| bool b = false; |
| ASTContext &C = BRC.getASTContext(); |
| if (R->isBoundable()) { |
| if (const TypedRegion *TR = dyn_cast<TypedRegion>(R)) { |
| if (TR->getValueType(C)->isObjCObjectPointerType()) { |
| os << "nil object reference stored to "; |
| b = true; |
| } |
| } |
| } |
| |
| if (!b) |
| os << "Null pointer value stored to "; |
| } |
| else if (V.isUndef()) { |
| os << "Uninitialized value stored to "; |
| } |
| else |
| return NULL; |
| |
| if (const VarRegion *VR = dyn_cast<VarRegion>(R)) { |
| os << '\'' << VR->getDecl()->getNameAsString() << '\''; |
| } |
| else |
| return NULL; |
| } |
| |
| // FIXME: Refactor this into BugReporterContext. |
| const Stmt *S = 0; |
| ProgramPoint P = N->getLocation(); |
| |
| if (BlockEdge *BE = dyn_cast<BlockEdge>(&P)) { |
| CFGBlock *BSrc = BE->getSrc(); |
| S = BSrc->getTerminatorCondition(); |
| } |
| else if (PostStmt *PS = dyn_cast<PostStmt>(&P)) { |
| S = PS->getStmt(); |
| } |
| |
| if (!S) |
| return NULL; |
| |
| // Construct a new PathDiagnosticPiece. |
| PathDiagnosticLocation L(S, BRC.getSourceManager()); |
| return new PathDiagnosticEventPiece(L, os.str()); |
| } |
| }; |
| |
| |
| static void registerFindLastStore(BugReporterContext& BRC, const MemRegion *R, |
| SVal V) { |
| BRC.addVisitor(new FindLastStoreBRVisitor(V, R)); |
| } |
| |
| class VISIBILITY_HIDDEN TrackConstraintBRVisitor : public BugReporterVisitor { |
| SVal Constraint; |
| const bool Assumption; |
| bool isSatisfied; |
| public: |
| TrackConstraintBRVisitor(SVal constraint, bool assumption) |
| : Constraint(constraint), Assumption(assumption), isSatisfied(false) {} |
| |
| PathDiagnosticPiece* VisitNode(const ExplodedNode<GRState> *N, |
| const ExplodedNode<GRState> *PrevN, |
| BugReporterContext& BRC) { |
| if (isSatisfied) |
| return NULL; |
| |
| // Check if in the previous state it was feasible for this constraint |
| // to *not* be true. |
| if (PrevN->getState()->assume(Constraint, !Assumption)) { |
| |
| isSatisfied = true; |
| |
| // As a sanity check, make sure that the negation of the constraint |
| // was infeasible in the current state. If it is feasible, we somehow |
| // missed the transition point. |
| if (N->getState()->assume(Constraint, !Assumption)) |
| return NULL; |
| |
| // We found the transition point for the constraint. We now need to |
| // pretty-print the constraint. (work-in-progress) |
| std::string sbuf; |
| llvm::raw_string_ostream os(sbuf); |
| |
| if (isa<Loc>(Constraint)) { |
| os << "Assuming pointer value is "; |
| os << (Assumption ? "non-null" : "null"); |
| } |
| |
| if (os.str().empty()) |
| return NULL; |
| |
| // FIXME: Refactor this into BugReporterContext. |
| const Stmt *S = 0; |
| ProgramPoint P = N->getLocation(); |
| |
| if (BlockEdge *BE = dyn_cast<BlockEdge>(&P)) { |
| CFGBlock *BSrc = BE->getSrc(); |
| S = BSrc->getTerminatorCondition(); |
| } |
| else if (PostStmt *PS = dyn_cast<PostStmt>(&P)) { |
| S = PS->getStmt(); |
| } |
| |
| if (!S) |
| return NULL; |
| |
| // Construct a new PathDiagnosticPiece. |
| PathDiagnosticLocation L(S, BRC.getSourceManager()); |
| return new PathDiagnosticEventPiece(L, os.str()); |
| } |
| |
| return NULL; |
| } |
| }; |
| } // end anonymous namespace |
| |
| static void registerTrackConstraint(BugReporterContext& BRC, SVal Constraint, |
| bool Assumption) { |
| BRC.addVisitor(new TrackConstraintBRVisitor(Constraint, Assumption)); |
| } |
| |
| void clang::bugreporter::registerTrackNullOrUndefValue(BugReporterContext& BRC, |
| const Stmt *S, |
| const ExplodedNode<GRState>* N) { |
| |
| if (!S) |
| return; |
| |
| GRStateManager &StateMgr = BRC.getStateManager(); |
| const GRState *state = N->getState(); |
| |
| if (const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(S)) { |
| if (const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl())) { |
| const VarRegion *R = |
| StateMgr.getRegionManager().getVarRegion(VD); |
| |
| // What did we load? |
| SVal V = state->getSVal(S); |
| |
| if (isa<loc::ConcreteInt>(V) || isa<nonloc::ConcreteInt>(V) |
| || V.isUndef()) { |
| registerFindLastStore(BRC, R, V); |
| } |
| } |
| } |
| |
| SVal V = state->getSValAsScalarOrLoc(S); |
| |
| // Uncomment this to find cases where we aren't properly getting the |
| // base value that was dereferenced. |
| // assert(!V.isUnknownOrUndef()); |
| |
| // Is it a symbolic value? |
| if (loc::MemRegionVal *L = dyn_cast<loc::MemRegionVal>(&V)) { |
| const SubRegion *R = cast<SubRegion>(L->getRegion()); |
| while (R && !isa<SymbolicRegion>(R)) { |
| R = dyn_cast<SubRegion>(R->getSuperRegion()); |
| } |
| |
| if (R) { |
| assert(isa<SymbolicRegion>(R)); |
| registerTrackConstraint(BRC, loc::MemRegionVal(R), false); |
| } |
| } |
| } |