| //=-- GRExprEngine.cpp - Path-Sensitive Expression-Level Dataflow ---*- 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 meta-engine for path-sensitive dataflow analysis that |
| // is built on GREngine, but provides the boilerplate to execute transfer |
| // functions and build the ExplodedGraph at the expression level. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "clang/Analysis/PathSensitive/GRExprEngine.h" |
| #include "llvm/Support/Streams.h" |
| |
| #ifndef NDEBUG |
| #include "llvm/Support/GraphWriter.h" |
| #include <sstream> |
| #endif |
| |
| // SaveAndRestore - A utility class that uses RIIA to save and restore |
| // the value of a variable. |
| template<typename T> |
| struct VISIBILITY_HIDDEN SaveAndRestore { |
| SaveAndRestore(T& x) : X(x), old_value(x) {} |
| ~SaveAndRestore() { X = old_value; } |
| T get() { return old_value; } |
| |
| T& X; |
| T old_value; |
| }; |
| |
| using namespace clang; |
| using llvm::dyn_cast; |
| using llvm::cast; |
| using llvm::APSInt; |
| |
| ValueState* GRExprEngine::getInitialState() { |
| |
| // The LiveVariables information already has a compilation of all VarDecls |
| // used in the function. Iterate through this set, and "symbolicate" |
| // any VarDecl whose value originally comes from outside the function. |
| |
| typedef LiveVariables::AnalysisDataTy LVDataTy; |
| LVDataTy& D = Liveness.getAnalysisData(); |
| |
| ValueState StateImpl = *StateMgr.getInitialState(); |
| |
| for (LVDataTy::decl_iterator I=D.begin_decl(), E=D.end_decl(); I != E; ++I) { |
| |
| VarDecl* VD = cast<VarDecl>(const_cast<ScopedDecl*>(I->first)); |
| |
| if (VD->hasGlobalStorage() || isa<ParmVarDecl>(VD)) { |
| RVal X = RVal::GetSymbolValue(SymMgr, VD); |
| StateMgr.BindVar(StateImpl, VD, X); |
| } |
| } |
| |
| return StateMgr.getPersistentState(StateImpl); |
| } |
| |
| ValueState* GRExprEngine::SetRVal(ValueState* St, Expr* Ex, RVal V) { |
| |
| if (!StateCleaned) { |
| St = RemoveDeadBindings(CurrentStmt, St); |
| StateCleaned = true; |
| } |
| |
| bool isBlkExpr = false; |
| |
| if (Ex == CurrentStmt) { |
| isBlkExpr = getCFG().isBlkExpr(Ex); |
| |
| if (!isBlkExpr) |
| return St; |
| } |
| |
| return StateMgr.SetRVal(St, Ex, V, isBlkExpr, false); |
| } |
| |
| ValueState* GRExprEngine::SetRVal(ValueState* St, LVal LV, RVal RV) { |
| |
| if (!StateCleaned) { |
| St = RemoveDeadBindings(CurrentStmt, St); |
| StateCleaned = true; |
| } |
| |
| return StateMgr.SetRVal(St, LV, RV); |
| } |
| |
| ValueState* GRExprEngine::MarkBranch(ValueState* St, Stmt* Terminator, |
| bool branchTaken) { |
| |
| switch (Terminator->getStmtClass()) { |
| default: |
| return St; |
| |
| case Stmt::BinaryOperatorClass: { // '&&' and '||' |
| |
| BinaryOperator* B = cast<BinaryOperator>(Terminator); |
| BinaryOperator::Opcode Op = B->getOpcode(); |
| |
| assert (Op == BinaryOperator::LAnd || Op == BinaryOperator::LOr); |
| |
| // For &&, if we take the true branch, then the value of the whole |
| // expression is that of the RHS expression. |
| // |
| // For ||, if we take the false branch, then the value of the whole |
| // expression is that of the RHS expression. |
| |
| Expr* Ex = (Op == BinaryOperator::LAnd && branchTaken) || |
| (Op == BinaryOperator::LOr && !branchTaken) |
| ? B->getRHS() : B->getLHS(); |
| |
| return SetBlkExprRVal(St, B, UndefinedVal(Ex)); |
| } |
| |
| case Stmt::ConditionalOperatorClass: { // ?: |
| |
| ConditionalOperator* C = cast<ConditionalOperator>(Terminator); |
| |
| // For ?, if branchTaken == true then the value is either the LHS or |
| // the condition itself. (GNU extension). |
| |
| Expr* Ex; |
| |
| if (branchTaken) |
| Ex = C->getLHS() ? C->getLHS() : C->getCond(); |
| else |
| Ex = C->getRHS(); |
| |
| return SetBlkExprRVal(St, C, UndefinedVal(Ex)); |
| } |
| |
| case Stmt::ChooseExprClass: { // ?: |
| |
| ChooseExpr* C = cast<ChooseExpr>(Terminator); |
| |
| Expr* Ex = branchTaken ? C->getLHS() : C->getRHS(); |
| return SetBlkExprRVal(St, C, UndefinedVal(Ex)); |
| } |
| } |
| } |
| |
| bool GRExprEngine::ProcessBlockEntrance(CFGBlock* B, ValueState*, |
| GRBlockCounter BC) { |
| |
| return BC.getNumVisited(B->getBlockID()) < 3; |
| } |
| |
| void GRExprEngine::ProcessBranch(Expr* Condition, Stmt* Term, |
| BranchNodeBuilder& builder) { |
| |
| // Remove old bindings for subexpressions. |
| ValueState* PrevState = StateMgr.RemoveSubExprBindings(builder.getState()); |
| |
| // Check for NULL conditions; e.g. "for(;;)" |
| if (!Condition) { |
| builder.markInfeasible(false); |
| return; |
| } |
| |
| RVal V = GetRVal(PrevState, Condition); |
| |
| switch (V.getBaseKind()) { |
| default: |
| break; |
| |
| case RVal::UnknownKind: |
| builder.generateNode(MarkBranch(PrevState, Term, true), true); |
| builder.generateNode(MarkBranch(PrevState, Term, false), false); |
| return; |
| |
| case RVal::UndefinedKind: { |
| NodeTy* N = builder.generateNode(PrevState, true); |
| |
| if (N) { |
| N->markAsSink(); |
| UndefBranches.insert(N); |
| } |
| |
| builder.markInfeasible(false); |
| return; |
| } |
| } |
| |
| |
| // Process the true branch. |
| |
| bool isFeasible = true; |
| ValueState* St = Assume(PrevState, V, true, isFeasible); |
| |
| if (isFeasible) |
| builder.generateNode(MarkBranch(St, Term, true), true); |
| else |
| builder.markInfeasible(true); |
| |
| // Process the false branch. |
| |
| isFeasible = false; |
| St = Assume(PrevState, V, false, isFeasible); |
| |
| if (isFeasible) |
| builder.generateNode(MarkBranch(St, Term, false), false); |
| else |
| builder.markInfeasible(false); |
| } |
| |
| /// ProcessIndirectGoto - Called by GRCoreEngine. Used to generate successor |
| /// nodes by processing the 'effects' of a computed goto jump. |
| void GRExprEngine::ProcessIndirectGoto(IndirectGotoNodeBuilder& builder) { |
| |
| ValueState* St = builder.getState(); |
| RVal V = GetRVal(St, builder.getTarget()); |
| |
| // Three possibilities: |
| // |
| // (1) We know the computed label. |
| // (2) The label is NULL (or some other constant), or Undefined. |
| // (3) We have no clue about the label. Dispatch to all targets. |
| // |
| |
| typedef IndirectGotoNodeBuilder::iterator iterator; |
| |
| if (isa<lval::GotoLabel>(V)) { |
| LabelStmt* L = cast<lval::GotoLabel>(V).getLabel(); |
| |
| for (iterator I=builder.begin(), E=builder.end(); I != E; ++I) { |
| if (I.getLabel() == L) { |
| builder.generateNode(I, St); |
| return; |
| } |
| } |
| |
| assert (false && "No block with label."); |
| return; |
| } |
| |
| if (isa<lval::ConcreteInt>(V) || isa<UndefinedVal>(V)) { |
| // Dispatch to the first target and mark it as a sink. |
| NodeTy* N = builder.generateNode(builder.begin(), St, true); |
| UndefBranches.insert(N); |
| return; |
| } |
| |
| // This is really a catch-all. We don't support symbolics yet. |
| |
| assert (V.isUnknown()); |
| |
| for (iterator I=builder.begin(), E=builder.end(); I != E; ++I) |
| builder.generateNode(I, St); |
| } |
| |
| /// ProcessSwitch - Called by GRCoreEngine. Used to generate successor |
| /// nodes by processing the 'effects' of a switch statement. |
| void GRExprEngine::ProcessSwitch(SwitchNodeBuilder& builder) { |
| |
| typedef SwitchNodeBuilder::iterator iterator; |
| |
| ValueState* St = builder.getState(); |
| Expr* CondE = builder.getCondition(); |
| RVal CondV = GetRVal(St, CondE); |
| |
| if (CondV.isUndef()) { |
| NodeTy* N = builder.generateDefaultCaseNode(St, true); |
| UndefBranches.insert(N); |
| return; |
| } |
| |
| ValueState* DefaultSt = St; |
| |
| // While most of this can be assumed (such as the signedness), having it |
| // just computed makes sure everything makes the same assumptions end-to-end. |
| |
| unsigned bits = getContext().getTypeSize(CondE->getType()); |
| |
| APSInt V1(bits, false); |
| APSInt V2 = V1; |
| |
| for (iterator I = builder.begin(), EI = builder.end(); I != EI; ++I) { |
| |
| CaseStmt* Case = cast<CaseStmt>(I.getCase()); |
| |
| // Evaluate the case. |
| if (!Case->getLHS()->isIntegerConstantExpr(V1, getContext(), 0, true)) { |
| assert (false && "Case condition must evaluate to an integer constant."); |
| return; |
| } |
| |
| // Get the RHS of the case, if it exists. |
| |
| if (Expr* E = Case->getRHS()) { |
| if (!E->isIntegerConstantExpr(V2, getContext(), 0, true)) { |
| assert (false && |
| "Case condition (RHS) must evaluate to an integer constant."); |
| return ; |
| } |
| |
| assert (V1 <= V2); |
| } |
| else V2 = V1; |
| |
| // FIXME: Eventually we should replace the logic below with a range |
| // comparison, rather than concretize the values within the range. |
| // This should be easy once we have "ranges" for NonLVals. |
| |
| do { |
| nonlval::ConcreteInt CaseVal(ValMgr.getValue(V1)); |
| |
| RVal Res = EvalBinOp(BinaryOperator::EQ, CondV, CaseVal); |
| |
| // Now "assume" that the case matches. |
| bool isFeasible = false; |
| |
| ValueState* StNew = Assume(St, Res, true, isFeasible); |
| |
| if (isFeasible) { |
| builder.generateCaseStmtNode(I, StNew); |
| |
| // If CondV evaluates to a constant, then we know that this |
| // is the *only* case that we can take, so stop evaluating the |
| // others. |
| if (isa<nonlval::ConcreteInt>(CondV)) |
| return; |
| } |
| |
| // Now "assume" that the case doesn't match. Add this state |
| // to the default state (if it is feasible). |
| |
| StNew = Assume(DefaultSt, Res, false, isFeasible); |
| |
| if (isFeasible) |
| DefaultSt = StNew; |
| |
| // Concretize the next value in the range. |
| ++V1; |
| |
| } while (V1 < V2); |
| } |
| |
| // If we reach here, than we know that the default branch is |
| // possible. |
| builder.generateDefaultCaseNode(DefaultSt); |
| } |
| |
| |
| void GRExprEngine::VisitLogicalExpr(BinaryOperator* B, NodeTy* Pred, |
| NodeSet& Dst) { |
| |
| assert (B->getOpcode() == BinaryOperator::LAnd || |
| B->getOpcode() == BinaryOperator::LOr); |
| |
| assert (B == CurrentStmt && getCFG().isBlkExpr(B)); |
| |
| ValueState* St = Pred->getState(); |
| RVal X = GetBlkExprRVal(St, B); |
| |
| assert (X.isUndef()); |
| |
| Expr* Ex = (Expr*) cast<UndefinedVal>(X).getData(); |
| |
| assert (Ex); |
| |
| if (Ex == B->getRHS()) { |
| |
| X = GetBlkExprRVal(St, Ex); |
| |
| // Handle undefined values. |
| |
| if (X.isUndef()) { |
| Nodify(Dst, B, Pred, SetBlkExprRVal(St, B, X)); |
| return; |
| } |
| |
| // We took the RHS. Because the value of the '&&' or '||' expression must |
| // evaluate to 0 or 1, we must assume the value of the RHS evaluates to 0 |
| // or 1. Alternatively, we could take a lazy approach, and calculate this |
| // value later when necessary. We don't have the machinery in place for |
| // this right now, and since most logical expressions are used for branches, |
| // the payoff is not likely to be large. Instead, we do eager evaluation. |
| |
| bool isFeasible = false; |
| ValueState* NewState = Assume(St, X, true, isFeasible); |
| |
| if (isFeasible) |
| Nodify(Dst, B, Pred, SetBlkExprRVal(NewState, B, MakeConstantVal(1U, B))); |
| |
| isFeasible = false; |
| NewState = Assume(St, X, false, isFeasible); |
| |
| if (isFeasible) |
| Nodify(Dst, B, Pred, SetBlkExprRVal(NewState, B, MakeConstantVal(0U, B))); |
| } |
| else { |
| // We took the LHS expression. Depending on whether we are '&&' or |
| // '||' we know what the value of the expression is via properties of |
| // the short-circuiting. |
| |
| X = MakeConstantVal( B->getOpcode() == BinaryOperator::LAnd ? 0U : 1U, B); |
| Nodify(Dst, B, Pred, SetBlkExprRVal(St, B, X)); |
| } |
| } |
| |
| |
| void GRExprEngine::ProcessStmt(Stmt* S, StmtNodeBuilder& builder) { |
| |
| Builder = &builder; |
| StmtEntryNode = builder.getLastNode(); |
| CurrentStmt = S; |
| NodeSet Dst; |
| StateCleaned = false; |
| |
| Visit(S, StmtEntryNode, Dst); |
| |
| // If no nodes were generated, generate a new node that has all the |
| // dead mappings removed. |
| |
| if (Dst.size() == 1 && *Dst.begin() == StmtEntryNode) { |
| ValueState* St = RemoveDeadBindings(S, StmtEntryNode->getState()); |
| builder.generateNode(S, St, StmtEntryNode); |
| } |
| |
| // For safety, NULL out these variables. |
| |
| CurrentStmt = NULL; |
| StmtEntryNode = NULL; |
| Builder = NULL; |
| } |
| |
| void GRExprEngine::VisitDeclRefExpr(DeclRefExpr* D, NodeTy* Pred, NodeSet& Dst){ |
| |
| if (D != CurrentStmt) { |
| Dst.Add(Pred); // No-op. Simply propagate the current state unchanged. |
| return; |
| } |
| |
| // If we are here, we are loading the value of the decl and binding |
| // it to the block-level expression. |
| |
| ValueState* St = Pred->getState(); |
| Nodify(Dst, D, Pred, SetRVal(St, D, GetRVal(St, D))); |
| } |
| |
| void GRExprEngine::VisitCall(CallExpr* CE, NodeTy* Pred, |
| CallExpr::arg_iterator AI, |
| CallExpr::arg_iterator AE, |
| NodeSet& Dst) { |
| |
| // Process the arguments. |
| |
| if (AI != AE) { |
| |
| NodeSet DstTmp; |
| Visit(*AI, Pred, DstTmp); |
| ++AI; |
| |
| for (NodeSet::iterator DI=DstTmp.begin(), DE=DstTmp.end(); DI != DE; ++DI) |
| VisitCall(CE, *DI, AI, AE, Dst); |
| |
| return; |
| } |
| |
| // If we reach here we have processed all of the arguments. Evaluate |
| // the callee expression. |
| |
| NodeSet DstTmp; |
| Expr* Callee = CE->getCallee()->IgnoreParenCasts(); |
| |
| VisitLVal(Callee, Pred, DstTmp); |
| |
| if (DstTmp.empty()) |
| DstTmp.Add(Pred); |
| |
| // Finally, evaluate the function call. |
| for (NodeSet::iterator DI = DstTmp.begin(), DE = DstTmp.end(); DI!=DE; ++DI) { |
| |
| ValueState* St = (*DI)->getState(); |
| RVal L = GetLVal(St, Callee); |
| |
| // FIXME: Add support for symbolic function calls (calls involving |
| // function pointer values that are symbolic). |
| |
| // Check for undefined control-flow or calls to NULL. |
| |
| if (L.isUndef() || isa<lval::ConcreteInt>(L)) { |
| NodeTy* N = Builder->generateNode(CE, St, *DI); |
| |
| if (N) { |
| N->markAsSink(); |
| BadCalls.insert(N); |
| } |
| |
| continue; |
| } |
| |
| // Check for the "noreturn" attribute. |
| |
| SaveAndRestore<bool> OldSink(Builder->BuildSinks); |
| |
| if (isa<lval::FuncVal>(L)) |
| if (cast<lval::FuncVal>(L).getDecl()->getAttr<NoReturnAttr>()) |
| Builder->BuildSinks = true; |
| |
| // Evaluate the call. |
| |
| |
| bool invalidateArgs = false; |
| |
| if (L.isUnknown()) { |
| // Check for an "unknown" callee. |
| invalidateArgs = true; |
| } |
| else if (isa<lval::FuncVal>(L)) { |
| |
| IdentifierInfo* Info = cast<lval::FuncVal>(L).getDecl()->getIdentifier(); |
| |
| if (unsigned id = Info->getBuiltinID()) { |
| switch (id) { |
| case Builtin::BI__builtin_expect: { |
| // For __builtin_expect, just return the value of the subexpression. |
| assert (CE->arg_begin() != CE->arg_end()); |
| RVal X = GetRVal(St, *(CE->arg_begin())); |
| Nodify(Dst, CE, *DI, SetRVal(St, CE, X)); |
| continue; |
| } |
| |
| default: |
| invalidateArgs = true; |
| break; |
| } |
| } |
| } |
| |
| if (invalidateArgs) { |
| // Invalidate all arguments passed in by reference (LVals). |
| for (CallExpr::arg_iterator I = CE->arg_begin(), E = CE->arg_end(); |
| I != E; ++I) { |
| RVal V = GetRVal(St, *I); |
| |
| if (isa<LVal>(V)) |
| St = SetRVal(St, cast<LVal>(V), UnknownVal()); |
| } |
| |
| Nodify(Dst, CE, *DI, St); |
| } |
| else { |
| |
| // Check any arguments passed-by-value against being undefined. |
| |
| bool badArg = false; |
| |
| for (CallExpr::arg_iterator I = CE->arg_begin(), E = CE->arg_end(); |
| I != E; ++I) { |
| |
| if (GetRVal((*DI)->getState(), *I).isUndef()) { |
| NodeTy* N = Builder->generateNode(CE, (*DI)->getState(), *DI); |
| |
| if (N) { |
| N->markAsSink(); |
| UndefArgs[N] = *I; |
| } |
| |
| badArg = true; |
| break; |
| } |
| } |
| |
| if (badArg) |
| continue; |
| |
| // Dispatch to the plug-in transfer function. |
| |
| unsigned size = Dst.size(); |
| |
| EvalCall(Dst, CE, cast<LVal>(L), *DI); |
| |
| if (!Builder->BuildSinks && Dst.size() == size) |
| Nodify(Dst, CE, *DI, St); |
| } |
| } |
| } |
| |
| void GRExprEngine::VisitCast(Expr* CastE, Expr* Ex, NodeTy* Pred, NodeSet& Dst){ |
| |
| NodeSet S1; |
| QualType T = CastE->getType(); |
| |
| if (T->isReferenceType()) |
| VisitLVal(Ex, Pred, S1); |
| else |
| Visit(Ex, Pred, S1); |
| |
| // Check for redundant casts or casting to "void" |
| if (T->isVoidType() || |
| Ex->getType() == T || |
| (T->isPointerType() && Ex->getType()->isFunctionType())) { |
| |
| for (NodeSet::iterator I1 = S1.begin(), E1 = S1.end(); I1 != E1; ++I1) |
| Dst.Add(*I1); |
| |
| return; |
| } |
| |
| for (NodeSet::iterator I1 = S1.begin(), E1 = S1.end(); I1 != E1; ++I1) { |
| NodeTy* N = *I1; |
| ValueState* St = N->getState(); |
| |
| RVal V = T->isReferenceType() ? GetLVal(St, Ex) : GetRVal(St, Ex); |
| |
| Nodify(Dst, CastE, N, SetRVal(St, CastE, EvalCast(V, CastE->getType()))); |
| } |
| } |
| |
| void GRExprEngine::VisitDeclStmt(DeclStmt* DS, GRExprEngine::NodeTy* Pred, |
| GRExprEngine::NodeSet& Dst) { |
| |
| ValueState* St = Pred->getState(); |
| |
| for (const ScopedDecl* D = DS->getDecl(); D; D = D->getNextDeclarator()) |
| if (const VarDecl* VD = dyn_cast<VarDecl>(D)) { |
| |
| // FIXME: Add support for local arrays. |
| if (VD->getType()->isArrayType()) |
| continue; |
| |
| const Expr* Ex = VD->getInit(); |
| |
| if (!VD->hasGlobalStorage() || VD->getStorageClass() == VarDecl::Static) { |
| |
| // In this context, Static => Local variable. |
| |
| assert (!VD->getStorageClass() == VarDecl::Static || |
| !isa<FileVarDecl>(VD)); |
| |
| // If there is no initializer, set the value of the |
| // variable to "Undefined". |
| // |
| // FIXME: static variables may have an initializer, but the second |
| // time a function is called those values may not be current. |
| |
| QualType T = VD->getType(); |
| |
| if ( VD->getStorageClass() == VarDecl::Static) { |
| |
| // C99: 6.7.8 Initialization |
| // If an object that has static storage duration is not initialized |
| // explicitly, then: |
| // —if it has pointer type, it is initialized to a null pointer; |
| // —if it has arithmetic type, it is initialized to (positive or |
| // unsigned) zero; |
| |
| // FIXME: Handle structs. Now we treat their values as unknown. |
| |
| if (T->isPointerType()) { |
| |
| St = SetRVal(St, lval::DeclVal(VD), |
| lval::ConcreteInt(ValMgr.getValue(0, T))); |
| } |
| else if (T->isIntegerType()) { |
| |
| St = SetRVal(St, lval::DeclVal(VD), |
| nonlval::ConcreteInt(ValMgr.getValue(0, T))); |
| } |
| |
| |
| } |
| else { |
| |
| // FIXME: Handle structs. Now we treat them as unknown. What |
| // we need to do is treat their members as unknown. |
| |
| if (T->isPointerType() || T->isIntegerType()) |
| St = SetRVal(St, lval::DeclVal(VD), |
| Ex ? GetRVal(St, Ex) : UndefinedVal()); |
| } |
| } |
| } |
| |
| Nodify(Dst, DS, Pred, St); |
| } |
| |
| |
| void GRExprEngine::VisitGuardedExpr(Expr* Ex, Expr* L, Expr* R, |
| NodeTy* Pred, NodeSet& Dst) { |
| |
| assert (Ex == CurrentStmt && getCFG().isBlkExpr(Ex)); |
| |
| ValueState* St = Pred->getState(); |
| RVal X = GetBlkExprRVal(St, Ex); |
| |
| assert (X.isUndef()); |
| |
| Expr* SE = (Expr*) cast<UndefinedVal>(X).getData(); |
| |
| assert (SE); |
| |
| X = GetBlkExprRVal(St, SE); |
| |
| // Make sure that we invalidate the previous binding. |
| Nodify(Dst, Ex, Pred, StateMgr.SetRVal(St, Ex, X, true, true)); |
| } |
| |
| /// VisitSizeOfAlignOfTypeExpr - Transfer function for sizeof(type). |
| void GRExprEngine::VisitSizeOfAlignOfTypeExpr(SizeOfAlignOfTypeExpr* Ex, |
| NodeTy* Pred, |
| NodeSet& Dst) { |
| |
| assert (Ex->isSizeOf() && "FIXME: AlignOf(Expr) not yet implemented."); |
| |
| // 6.5.3.4 sizeof: "The result type is an integer." |
| |
| QualType T = Ex->getArgumentType(); |
| |
| |
| // FIXME: Add support for VLAs. |
| if (!T.getTypePtr()->isConstantSizeType()) |
| return; |
| |
| |
| uint64_t size = 1; // Handle sizeof(void) |
| |
| if (T != getContext().VoidTy) |
| size = getContext().getTypeSize(T) / 8; |
| |
| Nodify(Dst, Ex, Pred, |
| SetRVal(Pred->getState(), Ex, |
| NonLVal::MakeVal(ValMgr, size, Ex->getType()))); |
| |
| } |
| |
| void GRExprEngine::VisitDeref(UnaryOperator* U, NodeTy* Pred, NodeSet& Dst) { |
| |
| Expr* Ex = U->getSubExpr()->IgnoreParens(); |
| |
| NodeSet DstTmp; |
| |
| if (isa<DeclRefExpr>(Ex)) |
| DstTmp.Add(Pred); |
| else |
| Visit(Ex, Pred, DstTmp); |
| |
| for (NodeSet::iterator I = DstTmp.begin(), DE = DstTmp.end(); I != DE; ++I) { |
| |
| NodeTy* N = *I; |
| ValueState* St = N->getState(); |
| |
| // FIXME: Bifurcate when dereferencing a symbolic with no constraints? |
| |
| RVal V = GetRVal(St, Ex); |
| |
| // Check for dereferences of undefined values. |
| |
| if (V.isUndef()) { |
| |
| NodeTy* Succ = Builder->generateNode(U, St, N); |
| |
| if (Succ) { |
| Succ->markAsSink(); |
| UndefDeref.insert(Succ); |
| } |
| |
| continue; |
| } |
| |
| // Check for dereferences of unknown values. Treat as No-Ops. |
| |
| if (V.isUnknown()) { |
| Dst.Add(N); |
| continue; |
| } |
| |
| // After a dereference, one of two possible situations arise: |
| // (1) A crash, because the pointer was NULL. |
| // (2) The pointer is not NULL, and the dereference works. |
| // |
| // We add these assumptions. |
| |
| LVal LV = cast<LVal>(V); |
| bool isFeasibleNotNull; |
| |
| // "Assume" that the pointer is Not-NULL. |
| |
| ValueState* StNotNull = Assume(St, LV, true, isFeasibleNotNull); |
| |
| if (isFeasibleNotNull) { |
| |
| // FIXME: Currently symbolic analysis "generates" new symbols |
| // for the contents of values. We need a better approach. |
| |
| Nodify(Dst, U, N, SetRVal(StNotNull, U, |
| GetRVal(StNotNull, LV, U->getType()))); |
| } |
| |
| bool isFeasibleNull; |
| |
| // Now "assume" that the pointer is NULL. |
| |
| ValueState* StNull = Assume(St, LV, false, isFeasibleNull); |
| |
| if (isFeasibleNull) { |
| |
| // We don't use "Nodify" here because the node will be a sink |
| // and we have no intention of processing it later. |
| |
| NodeTy* NullNode = Builder->generateNode(U, StNull, N); |
| |
| if (NullNode) { |
| |
| NullNode->markAsSink(); |
| |
| if (isFeasibleNotNull) ImplicitNullDeref.insert(NullNode); |
| else ExplicitNullDeref.insert(NullNode); |
| } |
| } |
| } |
| } |
| |
| void GRExprEngine::VisitUnaryOperator(UnaryOperator* U, NodeTy* Pred, |
| NodeSet& Dst) { |
| |
| NodeSet S1; |
| |
| assert (U->getOpcode() != UnaryOperator::Deref); |
| assert (U->getOpcode() != UnaryOperator::SizeOf); |
| assert (U->getOpcode() != UnaryOperator::AlignOf); |
| |
| bool use_GetLVal = false; |
| |
| switch (U->getOpcode()) { |
| case UnaryOperator::PostInc: |
| case UnaryOperator::PostDec: |
| case UnaryOperator::PreInc: |
| case UnaryOperator::PreDec: |
| case UnaryOperator::AddrOf: |
| // Evalue subexpression as an LVal. |
| use_GetLVal = true; |
| VisitLVal(U->getSubExpr(), Pred, S1); |
| break; |
| |
| default: |
| Visit(U->getSubExpr(), Pred, S1); |
| break; |
| } |
| |
| for (NodeSet::iterator I1 = S1.begin(), E1 = S1.end(); I1 != E1; ++I1) { |
| |
| NodeTy* N1 = *I1; |
| ValueState* St = N1->getState(); |
| |
| RVal SubV = use_GetLVal ? GetLVal(St, U->getSubExpr()) : |
| GetRVal(St, U->getSubExpr()); |
| |
| if (SubV.isUnknown()) { |
| Dst.Add(N1); |
| continue; |
| } |
| |
| if (SubV.isUndef()) { |
| Nodify(Dst, U, N1, SetRVal(St, U, SubV)); |
| continue; |
| } |
| |
| if (U->isIncrementDecrementOp()) { |
| |
| // Handle ++ and -- (both pre- and post-increment). |
| |
| LVal SubLV = cast<LVal>(SubV); |
| RVal V = GetRVal(St, SubLV, U->getType()); |
| |
| if (V.isUnknown()) { |
| Dst.Add(N1); |
| continue; |
| } |
| |
| // Propagate undefined values. |
| if (V.isUndef()) { |
| Nodify(Dst, U, N1, SetRVal(St, U, V)); |
| continue; |
| } |
| |
| // Handle all other values. |
| |
| BinaryOperator::Opcode Op = U->isIncrementOp() ? BinaryOperator::Add |
| : BinaryOperator::Sub; |
| |
| RVal Result = EvalBinOp(Op, V, MakeConstantVal(1U, U)); |
| |
| if (U->isPostfix()) |
| St = SetRVal(SetRVal(St, U, V), SubLV, Result); |
| else |
| St = SetRVal(SetRVal(St, U, Result), SubLV, Result); |
| |
| Nodify(Dst, U, N1, St); |
| continue; |
| } |
| |
| // Handle all other unary operators. |
| |
| switch (U->getOpcode()) { |
| |
| case UnaryOperator::Minus: |
| St = SetRVal(St, U, EvalMinus(U, cast<NonLVal>(SubV))); |
| break; |
| |
| case UnaryOperator::Not: |
| St = SetRVal(St, U, EvalComplement(cast<NonLVal>(SubV))); |
| break; |
| |
| case UnaryOperator::LNot: |
| |
| // C99 6.5.3.3: "The expression !E is equivalent to (0==E)." |
| // |
| // Note: technically we do "E == 0", but this is the same in the |
| // transfer functions as "0 == E". |
| |
| if (isa<LVal>(SubV)) { |
| lval::ConcreteInt V(ValMgr.getZeroWithPtrWidth()); |
| RVal Result = EvalBinOp(BinaryOperator::EQ, cast<LVal>(SubV), V); |
| St = SetRVal(St, U, Result); |
| } |
| else { |
| Expr* Ex = U->getSubExpr(); |
| nonlval::ConcreteInt V(ValMgr.getValue(0, Ex->getType())); |
| RVal Result = EvalBinOp(BinaryOperator::EQ, cast<NonLVal>(SubV), V); |
| St = SetRVal(St, U, Result); |
| } |
| |
| break; |
| |
| case UnaryOperator::AddrOf: { |
| assert (isa<LVal>(SubV)); |
| St = SetRVal(St, U, SubV); |
| break; |
| } |
| |
| default: ; |
| assert (false && "Not implemented."); |
| } |
| |
| Nodify(Dst, U, N1, St); |
| } |
| } |
| |
| void GRExprEngine::VisitSizeOfExpr(UnaryOperator* U, NodeTy* Pred, |
| NodeSet& Dst) { |
| |
| QualType T = U->getSubExpr()->getType(); |
| |
| // FIXME: Add support for VLAs. |
| if (!T.getTypePtr()->isConstantSizeType()) |
| return; |
| |
| uint64_t size = getContext().getTypeSize(T) / 8; |
| ValueState* St = Pred->getState(); |
| St = SetRVal(St, U, NonLVal::MakeVal(ValMgr, size, U->getType())); |
| |
| Nodify(Dst, U, Pred, St); |
| } |
| |
| void GRExprEngine::VisitLVal(Expr* Ex, NodeTy* Pred, NodeSet& Dst) { |
| |
| if (Ex != CurrentStmt && getCFG().isBlkExpr(Ex)) { |
| Dst.Add(Pred); |
| return; |
| } |
| |
| Ex = Ex->IgnoreParens(); |
| |
| if (isa<DeclRefExpr>(Ex)) { |
| Dst.Add(Pred); |
| return; |
| } |
| |
| if (UnaryOperator* U = dyn_cast<UnaryOperator>(Ex)) { |
| if (U->getOpcode() == UnaryOperator::Deref) { |
| Ex = U->getSubExpr()->IgnoreParens(); |
| |
| if (isa<DeclRefExpr>(Ex)) |
| Dst.Add(Pred); |
| else |
| Visit(Ex, Pred, Dst); |
| |
| return; |
| } |
| } |
| |
| Visit(Ex, Pred, Dst); |
| } |
| |
| void GRExprEngine::VisitBinaryOperator(BinaryOperator* B, |
| GRExprEngine::NodeTy* Pred, |
| GRExprEngine::NodeSet& Dst) { |
| NodeSet S1; |
| |
| if (B->isAssignmentOp()) |
| VisitLVal(B->getLHS(), Pred, S1); |
| else |
| Visit(B->getLHS(), Pred, S1); |
| |
| for (NodeSet::iterator I1=S1.begin(), E1=S1.end(); I1 != E1; ++I1) { |
| |
| NodeTy* N1 = *I1; |
| |
| // When getting the value for the LHS, check if we are in an assignment. |
| // In such cases, we want to (initially) treat the LHS as an LVal, |
| // so we use GetLVal instead of GetRVal so that DeclRefExpr's are |
| // evaluated to LValDecl's instead of to an NonLVal. |
| |
| RVal LeftV = B->isAssignmentOp() ? GetLVal(N1->getState(), B->getLHS()) |
| : GetRVal(N1->getState(), B->getLHS()); |
| |
| // Visit the RHS... |
| |
| NodeSet S2; |
| Visit(B->getRHS(), N1, S2); |
| |
| // Process the binary operator. |
| |
| for (NodeSet::iterator I2 = S2.begin(), E2 = S2.end(); I2 != E2; ++I2) { |
| |
| NodeTy* N2 = *I2; |
| ValueState* St = N2->getState(); |
| Expr* RHS = B->getRHS(); |
| RVal RightV = GetRVal(St, RHS); |
| |
| BinaryOperator::Opcode Op = B->getOpcode(); |
| |
| if ((Op == BinaryOperator::Div || Op == BinaryOperator::Rem) |
| && RHS->getType()->isIntegerType()) { |
| |
| // Check if the denominator is undefined. |
| |
| if (!RightV.isUnknown()) { |
| |
| if (RightV.isUndef()) { |
| NodeTy* DivUndef = Builder->generateNode(B, St, N2); |
| |
| if (DivUndef) { |
| DivUndef->markAsSink(); |
| ExplicitBadDivides.insert(DivUndef); |
| } |
| |
| continue; |
| } |
| |
| // Check for divide/remainder-by-zero. |
| // |
| // First, "assume" that the denominator is 0 or undefined. |
| |
| bool isFeasibleZero = false; |
| ValueState* ZeroSt = Assume(St, RightV, false, isFeasibleZero); |
| |
| // Second, "assume" that the denominator cannot be 0. |
| |
| bool isFeasibleNotZero = false; |
| St = Assume(St, RightV, true, isFeasibleNotZero); |
| |
| // Create the node for the divide-by-zero (if it occurred). |
| |
| if (isFeasibleZero) |
| if (NodeTy* DivZeroNode = Builder->generateNode(B, ZeroSt, N2)) { |
| DivZeroNode->markAsSink(); |
| |
| if (isFeasibleNotZero) |
| ImplicitBadDivides.insert(DivZeroNode); |
| else |
| ExplicitBadDivides.insert(DivZeroNode); |
| |
| } |
| |
| if (!isFeasibleNotZero) |
| continue; |
| } |
| |
| // Fall-through. The logic below processes the divide. |
| } |
| |
| |
| if (Op <= BinaryOperator::Or) { |
| |
| // Process non-assignements except commas or short-circuited |
| // logical expressions (LAnd and LOr). |
| |
| RVal Result = EvalBinOp(Op, LeftV, RightV); |
| |
| if (Result.isUnknown()) { |
| Dst.Add(N2); |
| continue; |
| } |
| |
| if (Result.isUndef() && !LeftV.isUndef() && !RightV.isUndef()) { |
| |
| // The operands were not undefined, but the result is undefined. |
| |
| if (NodeTy* UndefNode = Builder->generateNode(B, St, N2)) { |
| UndefNode->markAsSink(); |
| UndefResults.insert(UndefNode); |
| } |
| |
| continue; |
| } |
| |
| Nodify(Dst, B, N2, SetRVal(St, B, Result)); |
| continue; |
| } |
| |
| // Process assignments. |
| |
| switch (Op) { |
| |
| case BinaryOperator::Assign: { |
| |
| // Simple assignments. |
| |
| if (LeftV.isUndef()) { |
| HandleUndefinedStore(B, N2); |
| continue; |
| } |
| |
| if (LeftV.isUnknown()) { |
| St = SetRVal(St, B, RightV); |
| break; |
| } |
| |
| St = SetRVal(SetRVal(St, B, RightV), cast<LVal>(LeftV), RightV); |
| break; |
| } |
| |
| // Compound assignment operators. |
| |
| default: { |
| |
| assert (B->isCompoundAssignmentOp()); |
| |
| if (Op >= BinaryOperator::AndAssign) |
| ((int&) Op) -= (BinaryOperator::AndAssign - BinaryOperator::And); |
| else |
| ((int&) Op) -= BinaryOperator::MulAssign; |
| |
| // Check if the LHS is undefined. |
| |
| if (LeftV.isUndef()) { |
| HandleUndefinedStore(B, N2); |
| continue; |
| } |
| |
| if (LeftV.isUnknown()) { |
| |
| // While we do not know the location to store RightV, |
| // the entire expression does evaluate to RightV. |
| |
| if (RightV.isUnknown()) { |
| Dst.Add(N2); |
| continue; |
| } |
| |
| St = SetRVal(St, B, RightV); |
| break; |
| } |
| |
| // At this pointer we know that the LHS evaluates to an LVal |
| // that is neither "Unknown" or "Unintialized." |
| |
| LVal LeftLV = cast<LVal>(LeftV); |
| |
| // Fetch the value of the LHS (the value of the variable, etc.). |
| |
| RVal V = GetRVal(N1->getState(), LeftLV, B->getLHS()->getType()); |
| |
| // Propagate undefined value (left-side). We |
| // propogate undefined values for the RHS below when |
| // we also check for divide-by-zero. |
| |
| if (V.isUndef()) { |
| St = SetRVal(St, B, V); |
| break; |
| } |
| |
| // Propagate unknown values. |
| |
| if (V.isUnknown()) { |
| Dst.Add(N2); |
| continue; |
| } |
| |
| if (RightV.isUnknown()) { |
| St = SetRVal(SetRVal(St, LeftLV, RightV), B, RightV); |
| break; |
| } |
| |
| // At this point: |
| // |
| // The LHS is not Undef/Unknown. |
| // The RHS is not Unknown. |
| |
| // Get the computation type. |
| QualType CTy = cast<CompoundAssignOperator>(B)->getComputationType(); |
| |
| // Perform promotions. |
| V = EvalCast(V, CTy); |
| RightV = EvalCast(RightV, CTy); |
| |
| // Evaluate operands and promote to result type. |
| |
| if ((Op == BinaryOperator::Div || Op == BinaryOperator::Rem) |
| && RHS->getType()->isIntegerType()) { |
| |
| // Check if the denominator is undefined. |
| |
| if (RightV.isUndef()) { |
| NodeTy* DivUndef = Builder->generateNode(B, St, N2); |
| |
| if (DivUndef) { |
| DivUndef->markAsSink(); |
| ExplicitBadDivides.insert(DivUndef); |
| } |
| |
| continue; |
| } |
| |
| // First, "assume" that the denominator is 0. |
| |
| bool isFeasibleZero = false; |
| ValueState* ZeroSt = Assume(St, RightV, false, isFeasibleZero); |
| |
| // Second, "assume" that the denominator cannot be 0. |
| |
| bool isFeasibleNotZero = false; |
| St = Assume(St, RightV, true, isFeasibleNotZero); |
| |
| // Create the node for the divide-by-zero error (if it occurred). |
| |
| if (isFeasibleZero) { |
| NodeTy* DivZeroNode = Builder->generateNode(B, ZeroSt, N2); |
| |
| if (DivZeroNode) { |
| DivZeroNode->markAsSink(); |
| |
| if (isFeasibleNotZero) |
| ImplicitBadDivides.insert(DivZeroNode); |
| else |
| ExplicitBadDivides.insert(DivZeroNode); |
| } |
| } |
| |
| if (!isFeasibleNotZero) |
| continue; |
| |
| // Fall-through. The logic below processes the divide. |
| } |
| else { |
| |
| // Propagate undefined values (right-side). |
| |
| if (RightV.isUndef()) { |
| St = SetRVal(SetRVal(St, B, RightV), LeftLV, RightV); |
| break; |
| } |
| |
| } |
| |
| RVal Result = EvalCast(EvalBinOp(Op, V, RightV), B->getType()); |
| |
| if (Result.isUndef()) { |
| |
| // The operands were not undefined, but the result is undefined. |
| |
| if (NodeTy* UndefNode = Builder->generateNode(B, St, N2)) { |
| UndefNode->markAsSink(); |
| UndefResults.insert(UndefNode); |
| } |
| |
| continue; |
| } |
| |
| St = SetRVal(SetRVal(St, B, Result), LeftLV, Result); |
| } |
| } |
| |
| Nodify(Dst, B, N2, St); |
| } |
| } |
| } |
| |
| void GRExprEngine::HandleUndefinedStore(Stmt* S, NodeTy* Pred) { |
| NodeTy* N = Builder->generateNode(S, Pred->getState(), Pred); |
| N->markAsSink(); |
| UndefStores.insert(N); |
| } |
| |
| void GRExprEngine::Visit(Stmt* S, NodeTy* Pred, NodeSet& Dst) { |
| |
| // FIXME: add metadata to the CFG so that we can disable |
| // this check when we KNOW that there is no block-level subexpression. |
| // The motivation is that this check requires a hashtable lookup. |
| |
| if (S != CurrentStmt && getCFG().isBlkExpr(S)) { |
| Dst.Add(Pred); |
| return; |
| } |
| |
| switch (S->getStmtClass()) { |
| |
| default: |
| // Cases we intentionally have "default" handle: |
| // AddrLabelExpr, IntegerLiteral, CharacterLiteral |
| |
| Dst.Add(Pred); // No-op. Simply propagate the current state unchanged. |
| break; |
| |
| case Stmt::BinaryOperatorClass: { |
| BinaryOperator* B = cast<BinaryOperator>(S); |
| |
| if (B->isLogicalOp()) { |
| VisitLogicalExpr(B, Pred, Dst); |
| break; |
| } |
| else if (B->getOpcode() == BinaryOperator::Comma) { |
| ValueState* St = Pred->getState(); |
| Nodify(Dst, B, Pred, SetRVal(St, B, GetRVal(St, B->getRHS()))); |
| break; |
| } |
| |
| VisitBinaryOperator(cast<BinaryOperator>(S), Pred, Dst); |
| break; |
| } |
| |
| case Stmt::CallExprClass: { |
| CallExpr* C = cast<CallExpr>(S); |
| VisitCall(C, Pred, C->arg_begin(), C->arg_end(), Dst); |
| break; |
| } |
| |
| case Stmt::CastExprClass: { |
| CastExpr* C = cast<CastExpr>(S); |
| VisitCast(C, C->getSubExpr(), Pred, Dst); |
| break; |
| } |
| |
| // FIXME: ChooseExpr is really a constant. We need to fix |
| // the CFG do not model them as explicit control-flow. |
| |
| case Stmt::ChooseExprClass: { // __builtin_choose_expr |
| ChooseExpr* C = cast<ChooseExpr>(S); |
| VisitGuardedExpr(C, C->getLHS(), C->getRHS(), Pred, Dst); |
| break; |
| } |
| |
| case Stmt::CompoundAssignOperatorClass: |
| VisitBinaryOperator(cast<BinaryOperator>(S), Pred, Dst); |
| break; |
| |
| case Stmt::ConditionalOperatorClass: { // '?' operator |
| ConditionalOperator* C = cast<ConditionalOperator>(S); |
| VisitGuardedExpr(C, C->getLHS(), C->getRHS(), Pred, Dst); |
| break; |
| } |
| |
| case Stmt::DeclRefExprClass: |
| VisitDeclRefExpr(cast<DeclRefExpr>(S), Pred, Dst); |
| break; |
| |
| case Stmt::DeclStmtClass: |
| VisitDeclStmt(cast<DeclStmt>(S), Pred, Dst); |
| break; |
| |
| case Stmt::ImplicitCastExprClass: { |
| ImplicitCastExpr* C = cast<ImplicitCastExpr>(S); |
| VisitCast(C, C->getSubExpr(), Pred, Dst); |
| break; |
| } |
| |
| case Stmt::ParenExprClass: |
| Visit(cast<ParenExpr>(S)->getSubExpr(), Pred, Dst); |
| break; |
| |
| case Stmt::SizeOfAlignOfTypeExprClass: |
| VisitSizeOfAlignOfTypeExpr(cast<SizeOfAlignOfTypeExpr>(S), Pred, Dst); |
| break; |
| |
| case Stmt::StmtExprClass: { |
| StmtExpr* SE = cast<StmtExpr>(S); |
| |
| ValueState* St = Pred->getState(); |
| Expr* LastExpr = cast<Expr>(*SE->getSubStmt()->body_rbegin()); |
| Nodify(Dst, SE, Pred, SetRVal(St, SE, GetRVal(St, LastExpr))); |
| break; |
| } |
| |
| // FIXME: We may wish to always bind state to ReturnStmts so |
| // that users can quickly query what was the state at the |
| // exit points of a function. |
| |
| case Stmt::ReturnStmtClass: { |
| if (Expr* R = cast<ReturnStmt>(S)->getRetValue()) |
| Visit(R, Pred, Dst); |
| else |
| Dst.Add(Pred); |
| |
| break; |
| } |
| |
| case Stmt::UnaryOperatorClass: { |
| UnaryOperator* U = cast<UnaryOperator>(S); |
| |
| switch (U->getOpcode()) { |
| case UnaryOperator::Deref: VisitDeref(U, Pred, Dst); break; |
| case UnaryOperator::Plus: Visit(U->getSubExpr(), Pred, Dst); break; |
| case UnaryOperator::SizeOf: VisitSizeOfExpr(U, Pred, Dst); break; |
| default: VisitUnaryOperator(U, Pred, Dst); break; |
| } |
| |
| break; |
| } |
| } |
| } |
| |
| //===----------------------------------------------------------------------===// |
| // "Assume" logic. |
| //===----------------------------------------------------------------------===// |
| |
| ValueState* GRExprEngine::Assume(ValueState* St, LVal Cond, |
| bool Assumption, |
| bool& isFeasible) { |
| switch (Cond.getSubKind()) { |
| default: |
| assert (false && "'Assume' not implemented for this LVal."); |
| return St; |
| |
| case lval::SymbolValKind: |
| if (Assumption) |
| return AssumeSymNE(St, cast<lval::SymbolVal>(Cond).getSymbol(), |
| ValMgr.getZeroWithPtrWidth(), isFeasible); |
| else |
| return AssumeSymEQ(St, cast<lval::SymbolVal>(Cond).getSymbol(), |
| ValMgr.getZeroWithPtrWidth(), isFeasible); |
| |
| |
| case lval::DeclValKind: |
| case lval::FuncValKind: |
| case lval::GotoLabelKind: |
| isFeasible = Assumption; |
| return St; |
| |
| case lval::ConcreteIntKind: { |
| bool b = cast<lval::ConcreteInt>(Cond).getValue() != 0; |
| isFeasible = b ? Assumption : !Assumption; |
| return St; |
| } |
| } |
| } |
| |
| ValueState* GRExprEngine::Assume(ValueState* St, NonLVal Cond, |
| bool Assumption, |
| bool& isFeasible) { |
| switch (Cond.getSubKind()) { |
| default: |
| assert (false && "'Assume' not implemented for this NonLVal."); |
| return St; |
| |
| |
| case nonlval::SymbolValKind: { |
| nonlval::SymbolVal& SV = cast<nonlval::SymbolVal>(Cond); |
| SymbolID sym = SV.getSymbol(); |
| |
| if (Assumption) |
| return AssumeSymNE(St, sym, ValMgr.getValue(0, SymMgr.getType(sym)), |
| isFeasible); |
| else |
| return AssumeSymEQ(St, sym, ValMgr.getValue(0, SymMgr.getType(sym)), |
| isFeasible); |
| } |
| |
| case nonlval::SymIntConstraintValKind: |
| return |
| AssumeSymInt(St, Assumption, |
| cast<nonlval::SymIntConstraintVal>(Cond).getConstraint(), |
| isFeasible); |
| |
| case nonlval::ConcreteIntKind: { |
| bool b = cast<nonlval::ConcreteInt>(Cond).getValue() != 0; |
| isFeasible = b ? Assumption : !Assumption; |
| return St; |
| } |
| } |
| } |
| |
| ValueState* |
| GRExprEngine::AssumeSymNE(ValueState* St, SymbolID sym, |
| const llvm::APSInt& V, bool& isFeasible) { |
| |
| // First, determine if sym == X, where X != V. |
| if (const llvm::APSInt* X = St->getSymVal(sym)) { |
| isFeasible = *X != V; |
| return St; |
| } |
| |
| // Second, determine if sym != V. |
| if (St->isNotEqual(sym, V)) { |
| isFeasible = true; |
| return St; |
| } |
| |
| // If we reach here, sym is not a constant and we don't know if it is != V. |
| // Make that assumption. |
| |
| isFeasible = true; |
| return StateMgr.AddNE(St, sym, V); |
| } |
| |
| ValueState* |
| GRExprEngine::AssumeSymEQ(ValueState* St, SymbolID sym, |
| const llvm::APSInt& V, bool& isFeasible) { |
| |
| // First, determine if sym == X, where X != V. |
| if (const llvm::APSInt* X = St->getSymVal(sym)) { |
| isFeasible = *X == V; |
| return St; |
| } |
| |
| // Second, determine if sym != V. |
| if (St->isNotEqual(sym, V)) { |
| isFeasible = false; |
| return St; |
| } |
| |
| // If we reach here, sym is not a constant and we don't know if it is == V. |
| // Make that assumption. |
| |
| isFeasible = true; |
| return StateMgr.AddEQ(St, sym, V); |
| } |
| |
| ValueState* |
| GRExprEngine::AssumeSymInt(ValueState* St, bool Assumption, |
| const SymIntConstraint& C, bool& isFeasible) { |
| |
| switch (C.getOpcode()) { |
| default: |
| // No logic yet for other operators. |
| return St; |
| |
| case BinaryOperator::EQ: |
| if (Assumption) |
| return AssumeSymEQ(St, C.getSymbol(), C.getInt(), isFeasible); |
| else |
| return AssumeSymNE(St, C.getSymbol(), C.getInt(), isFeasible); |
| |
| case BinaryOperator::NE: |
| if (Assumption) |
| return AssumeSymNE(St, C.getSymbol(), C.getInt(), isFeasible); |
| else |
| return AssumeSymEQ(St, C.getSymbol(), C.getInt(), isFeasible); |
| } |
| } |
| |
| //===----------------------------------------------------------------------===// |
| // Visualization. |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef NDEBUG |
| static GRExprEngine* GraphPrintCheckerState; |
| |
| namespace llvm { |
| template<> |
| struct VISIBILITY_HIDDEN DOTGraphTraits<GRExprEngine::NodeTy*> : |
| public DefaultDOTGraphTraits { |
| |
| static void PrintVarBindings(std::ostream& Out, ValueState* St) { |
| |
| Out << "Variables:\\l"; |
| |
| bool isFirst = true; |
| |
| for (ValueState::vb_iterator I=St->vb_begin(), E=St->vb_end(); I!=E;++I) { |
| |
| if (isFirst) |
| isFirst = false; |
| else |
| Out << "\\l"; |
| |
| Out << ' ' << I.getKey()->getName() << " : "; |
| I.getData().print(Out); |
| } |
| |
| } |
| |
| |
| static void PrintSubExprBindings(std::ostream& Out, ValueState* St){ |
| |
| bool isFirst = true; |
| |
| for (ValueState::seb_iterator I=St->seb_begin(), E=St->seb_end();I!=E;++I) { |
| |
| if (isFirst) { |
| Out << "\\l\\lSub-Expressions:\\l"; |
| isFirst = false; |
| } |
| else |
| Out << "\\l"; |
| |
| Out << " (" << (void*) I.getKey() << ") "; |
| I.getKey()->printPretty(Out); |
| Out << " : "; |
| I.getData().print(Out); |
| } |
| } |
| |
| static void PrintBlkExprBindings(std::ostream& Out, ValueState* St){ |
| |
| bool isFirst = true; |
| |
| for (ValueState::beb_iterator I=St->beb_begin(), E=St->beb_end(); I!=E;++I){ |
| if (isFirst) { |
| Out << "\\l\\lBlock-level Expressions:\\l"; |
| isFirst = false; |
| } |
| else |
| Out << "\\l"; |
| |
| Out << " (" << (void*) I.getKey() << ") "; |
| I.getKey()->printPretty(Out); |
| Out << " : "; |
| I.getData().print(Out); |
| } |
| } |
| |
| static void PrintEQ(std::ostream& Out, ValueState* St) { |
| ValueState::ConstEqTy CE = St->ConstEq; |
| |
| if (CE.isEmpty()) |
| return; |
| |
| Out << "\\l\\|'==' constraints:"; |
| |
| for (ValueState::ConstEqTy::iterator I=CE.begin(), E=CE.end(); I!=E;++I) |
| Out << "\\l $" << I.getKey() << " : " << I.getData()->toString(); |
| } |
| |
| static void PrintNE(std::ostream& Out, ValueState* St) { |
| ValueState::ConstNotEqTy NE = St->ConstNotEq; |
| |
| if (NE.isEmpty()) |
| return; |
| |
| Out << "\\l\\|'!=' constraints:"; |
| |
| for (ValueState::ConstNotEqTy::iterator I=NE.begin(), EI=NE.end(); |
| I != EI; ++I){ |
| |
| Out << "\\l $" << I.getKey() << " : "; |
| bool isFirst = true; |
| |
| ValueState::IntSetTy::iterator J=I.getData().begin(), |
| EJ=I.getData().end(); |
| for ( ; J != EJ; ++J) { |
| if (isFirst) isFirst = false; |
| else Out << ", "; |
| |
| Out << (*J)->toString(); |
| } |
| } |
| } |
| |
| static std::string getNodeAttributes(const GRExprEngine::NodeTy* N, void*) { |
| |
| if (GraphPrintCheckerState->isImplicitNullDeref(N) || |
| GraphPrintCheckerState->isExplicitNullDeref(N) || |
| GraphPrintCheckerState->isUndefDeref(N) || |
| GraphPrintCheckerState->isUndefStore(N) || |
| GraphPrintCheckerState->isUndefControlFlow(N) || |
| GraphPrintCheckerState->isExplicitBadDivide(N) || |
| GraphPrintCheckerState->isImplicitBadDivide(N) || |
| GraphPrintCheckerState->isUndefResult(N) || |
| GraphPrintCheckerState->isBadCall(N) || |
| GraphPrintCheckerState->isUndefArg(N)) |
| return "color=\"red\",style=\"filled\""; |
| |
| if (GraphPrintCheckerState->isNoReturnCall(N)) |
| return "color=\"blue\",style=\"filled\""; |
| |
| return ""; |
| } |
| |
| static std::string getNodeLabel(const GRExprEngine::NodeTy* N, void*) { |
| std::ostringstream Out; |
| |
| // Program Location. |
| ProgramPoint Loc = N->getLocation(); |
| |
| switch (Loc.getKind()) { |
| case ProgramPoint::BlockEntranceKind: |
| Out << "Block Entrance: B" |
| << cast<BlockEntrance>(Loc).getBlock()->getBlockID(); |
| break; |
| |
| case ProgramPoint::BlockExitKind: |
| assert (false); |
| break; |
| |
| case ProgramPoint::PostStmtKind: { |
| const PostStmt& L = cast<PostStmt>(Loc); |
| Out << L.getStmt()->getStmtClassName() << ':' |
| << (void*) L.getStmt() << ' '; |
| |
| L.getStmt()->printPretty(Out); |
| |
| if (GraphPrintCheckerState->isImplicitNullDeref(N)) |
| Out << "\\|Implicit-Null Dereference.\\l"; |
| else if (GraphPrintCheckerState->isExplicitNullDeref(N)) |
| Out << "\\|Explicit-Null Dereference.\\l"; |
| else if (GraphPrintCheckerState->isUndefDeref(N)) |
| Out << "\\|Dereference of undefialied value.\\l"; |
| else if (GraphPrintCheckerState->isUndefStore(N)) |
| Out << "\\|Store to Undefined LVal."; |
| else if (GraphPrintCheckerState->isExplicitBadDivide(N)) |
| Out << "\\|Explicit divide-by zero or undefined value."; |
| else if (GraphPrintCheckerState->isImplicitBadDivide(N)) |
| Out << "\\|Implicit divide-by zero or undefined value."; |
| else if (GraphPrintCheckerState->isUndefResult(N)) |
| Out << "\\|Result of operation is undefined."; |
| else if (GraphPrintCheckerState->isNoReturnCall(N)) |
| Out << "\\|Call to function marked \"noreturn\"."; |
| else if (GraphPrintCheckerState->isBadCall(N)) |
| Out << "\\|Call to NULL/Undefined."; |
| else if (GraphPrintCheckerState->isUndefArg(N)) |
| Out << "\\|Argument in call is undefined"; |
| |
| break; |
| } |
| |
| default: { |
| const BlockEdge& E = cast<BlockEdge>(Loc); |
| Out << "Edge: (B" << E.getSrc()->getBlockID() << ", B" |
| << E.getDst()->getBlockID() << ')'; |
| |
| if (Stmt* T = E.getSrc()->getTerminator()) { |
| Out << "\\|Terminator: "; |
| E.getSrc()->printTerminator(Out); |
| |
| if (isa<SwitchStmt>(T)) { |
| Stmt* Label = E.getDst()->getLabel(); |
| |
| if (Label) { |
| if (CaseStmt* C = dyn_cast<CaseStmt>(Label)) { |
| Out << "\\lcase "; |
| C->getLHS()->printPretty(Out); |
| |
| if (Stmt* RHS = C->getRHS()) { |
| Out << " .. "; |
| RHS->printPretty(Out); |
| } |
| |
| Out << ":"; |
| } |
| else { |
| assert (isa<DefaultStmt>(Label)); |
| Out << "\\ldefault:"; |
| } |
| } |
| else |
| Out << "\\l(implicit) default:"; |
| } |
| else if (isa<IndirectGotoStmt>(T)) { |
| // FIXME |
| } |
| else { |
| Out << "\\lCondition: "; |
| if (*E.getSrc()->succ_begin() == E.getDst()) |
| Out << "true"; |
| else |
| Out << "false"; |
| } |
| |
| Out << "\\l"; |
| } |
| |
| if (GraphPrintCheckerState->isUndefControlFlow(N)) { |
| Out << "\\|Control-flow based on\\lUndefined value.\\l"; |
| } |
| } |
| } |
| |
| Out << "\\|StateID: " << (void*) N->getState() << "\\|"; |
| |
| N->getState()->printDOT(Out); |
| |
| Out << "\\l"; |
| return Out.str(); |
| } |
| }; |
| } // end llvm namespace |
| #endif |
| |
| void GRExprEngine::ViewGraph() { |
| #ifndef NDEBUG |
| GraphPrintCheckerState = this; |
| llvm::ViewGraph(*G.roots_begin(), "GRExprEngine"); |
| GraphPrintCheckerState = NULL; |
| #endif |
| } |