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llvm-project/clang/lib/Checker/GRExprEngine.cpp

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//=-- 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 "GRExprEngineInternalChecks.h"
#include "clang/Checker/BugReporter/BugType.h"
#include "clang/Checker/PathSensitive/AnalysisManager.h"
#include "clang/Checker/PathSensitive/GRExprEngine.h"
#include "clang/Checker/PathSensitive/GRExprEngineBuilders.h"
#include "clang/Checker/PathSensitive/Checker.h"
#include "clang/AST/CharUnits.h"
#include "clang/AST/ParentMap.h"
#include "clang/AST/StmtObjC.h"
#include "clang/AST/DeclCXX.h"
#include "clang/Basic/Builtins.h"
#include "clang/Basic/SourceManager.h"
#include "clang/Basic/SourceManager.h"
#include "clang/Basic/PrettyStackTrace.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/ADT/ImmutableList.h"
#ifndef NDEBUG
#include "llvm/Support/GraphWriter.h"
#endif
using namespace clang;
using llvm::dyn_cast;
using llvm::dyn_cast_or_null;
using llvm::cast;
using llvm::APSInt;
namespace {
// Trait class for recording returned expression in the state.
struct ReturnExpr {
static int TagInt;
typedef const Stmt *data_type;
};
int ReturnExpr::TagInt;
}
//===----------------------------------------------------------------------===//
// Utility functions.
//===----------------------------------------------------------------------===//
static inline Selector GetNullarySelector(const char* name, ASTContext& Ctx) {
IdentifierInfo* II = &Ctx.Idents.get(name);
return Ctx.Selectors.getSelector(0, &II);
}
static QualType GetCalleeReturnType(const CallExpr *CE) {
const Expr *Callee = CE->getCallee();
QualType T = Callee->getType();
if (const PointerType *PT = T->getAs<PointerType>()) {
const FunctionType *FT = PT->getPointeeType()->getAs<FunctionType>();
T = FT->getResultType();
}
else {
const BlockPointerType *BT = T->getAs<BlockPointerType>();
T = BT->getPointeeType()->getAs<FunctionType>()->getResultType();
}
return T;
}
static bool CalleeReturnsReference(const CallExpr *CE) {
return (bool) GetCalleeReturnType(CE)->getAs<ReferenceType>();
}
static bool ReceiverReturnsReference(const ObjCMessageExpr *ME) {
const ObjCMethodDecl *MD = ME->getMethodDecl();
if (!MD)
return false;
return MD->getResultType()->getAs<ReferenceType>();
}
#ifndef NDEBUG
static bool ReceiverReturnsReferenceOrRecord(const ObjCMessageExpr *ME) {
const ObjCMethodDecl *MD = ME->getMethodDecl();
if (!MD)
return false;
QualType T = MD->getResultType();
return T->getAs<RecordType>() || T->getAs<ReferenceType>();
}
static bool CalleeReturnsReferenceOrRecord(const CallExpr *CE) {
QualType T = GetCalleeReturnType(CE);
return T->getAs<ReferenceType>() || T->getAs<RecordType>();
}
#endif
//===----------------------------------------------------------------------===//
// Batch auditor. DEPRECATED.
//===----------------------------------------------------------------------===//
namespace {
class MappedBatchAuditor : public GRSimpleAPICheck {
typedef llvm::ImmutableList<GRSimpleAPICheck*> Checks;
typedef llvm::DenseMap<void*,Checks> MapTy;
MapTy M;
Checks::Factory F;
Checks AllStmts;
public:
MappedBatchAuditor(llvm::BumpPtrAllocator& Alloc) :
F(Alloc), AllStmts(F.GetEmptyList()) {}
virtual ~MappedBatchAuditor() {
llvm::DenseSet<GRSimpleAPICheck*> AlreadyVisited;
for (MapTy::iterator MI = M.begin(), ME = M.end(); MI != ME; ++MI)
for (Checks::iterator I=MI->second.begin(), E=MI->second.end(); I!=E;++I){
GRSimpleAPICheck* check = *I;
if (AlreadyVisited.count(check))
continue;
AlreadyVisited.insert(check);
delete check;
}
}
void AddCheck(GRSimpleAPICheck *A, Stmt::StmtClass C) {
assert (A && "Check cannot be null.");
void* key = reinterpret_cast<void*>((uintptr_t) C);
MapTy::iterator I = M.find(key);
M[key] = F.Concat(A, I == M.end() ? F.GetEmptyList() : I->second);
}
void AddCheck(GRSimpleAPICheck *A) {
assert (A && "Check cannot be null.");
AllStmts = F.Concat(A, AllStmts);
}
virtual bool Audit(ExplodedNode* N, GRStateManager& VMgr) {
// First handle the auditors that accept all statements.
bool isSink = false;
for (Checks::iterator I = AllStmts.begin(), E = AllStmts.end(); I!=E; ++I)
isSink |= (*I)->Audit(N, VMgr);
// Next handle the auditors that accept only specific statements.
const Stmt* S = cast<PostStmt>(N->getLocation()).getStmt();
void* key = reinterpret_cast<void*>((uintptr_t) S->getStmtClass());
MapTy::iterator MI = M.find(key);
if (MI != M.end()) {
for (Checks::iterator I=MI->second.begin(), E=MI->second.end(); I!=E; ++I)
isSink |= (*I)->Audit(N, VMgr);
}
return isSink;
}
};
} // end anonymous namespace
//===----------------------------------------------------------------------===//
// Checker worklist routines.
//===----------------------------------------------------------------------===//
void GRExprEngine::CheckerVisit(Stmt *S, ExplodedNodeSet &Dst,
ExplodedNodeSet &Src, bool isPrevisit) {
if (Checkers.empty()) {
Dst.insert(Src);
return;
}
ExplodedNodeSet Tmp;
ExplodedNodeSet *PrevSet = &Src;
for (CheckersOrdered::iterator I=Checkers.begin(),E=Checkers.end(); I!=E;++I){
ExplodedNodeSet *CurrSet = 0;
if (I+1 == E)
CurrSet = &Dst;
else {
CurrSet = (PrevSet == &Tmp) ? &Src : &Tmp;
CurrSet->clear();
}
void *tag = I->first;
Checker *checker = I->second;
for (ExplodedNodeSet::iterator NI = PrevSet->begin(), NE = PrevSet->end();
NI != NE; ++NI)
checker->GR_Visit(*CurrSet, *Builder, *this, S, *NI, tag, isPrevisit);
PrevSet = CurrSet;
}
// Don't autotransition. The CheckerContext objects should do this
// automatically.
}
void GRExprEngine::CheckerEvalNilReceiver(const ObjCMessageExpr *ME,
ExplodedNodeSet &Dst,
const GRState *state,
ExplodedNode *Pred) {
bool Evaluated = false;
ExplodedNodeSet DstTmp;
for (CheckersOrdered::iterator I=Checkers.begin(),E=Checkers.end();I!=E;++I) {
void *tag = I->first;
Checker *checker = I->second;
if (checker->GR_EvalNilReceiver(DstTmp, *Builder, *this, ME, Pred, state,
tag)) {
Evaluated = true;
break;
} else
// The checker didn't evaluate the expr. Restore the Dst.
DstTmp.clear();
}
if (Evaluated)
Dst.insert(DstTmp);
else
Dst.insert(Pred);
}
// CheckerEvalCall returns true if one of the checkers processed the node.
// This may return void when all call evaluation logic goes to some checker
// in the future.
bool GRExprEngine::CheckerEvalCall(const CallExpr *CE,
ExplodedNodeSet &Dst,
ExplodedNode *Pred) {
bool Evaluated = false;
ExplodedNodeSet DstTmp;
for (CheckersOrdered::iterator I=Checkers.begin(),E=Checkers.end();I!=E;++I) {
void *tag = I->first;
Checker *checker = I->second;
if (checker->GR_EvalCallExpr(DstTmp, *Builder, *this, CE, Pred, tag)) {
Evaluated = true;
break;
} else
// The checker didn't evaluate the expr. Restore the DstTmp set.
DstTmp.clear();
}
if (Evaluated)
Dst.insert(DstTmp);
else
Dst.insert(Pred);
return Evaluated;
}
// FIXME: This is largely copy-paste from CheckerVisit(). Need to
// unify.
void GRExprEngine::CheckerVisitBind(const Stmt *AssignE, const Stmt *StoreE,
ExplodedNodeSet &Dst,
ExplodedNodeSet &Src,
SVal location, SVal val, bool isPrevisit) {
if (Checkers.empty()) {
Dst.insert(Src);
return;
}
ExplodedNodeSet Tmp;
ExplodedNodeSet *PrevSet = &Src;
for (CheckersOrdered::iterator I=Checkers.begin(),E=Checkers.end(); I!=E; ++I)
{
ExplodedNodeSet *CurrSet = 0;
if (I+1 == E)
CurrSet = &Dst;
else {
CurrSet = (PrevSet == &Tmp) ? &Src : &Tmp;
CurrSet->clear();
}
void *tag = I->first;
Checker *checker = I->second;
for (ExplodedNodeSet::iterator NI = PrevSet->begin(), NE = PrevSet->end();
NI != NE; ++NI)
checker->GR_VisitBind(*CurrSet, *Builder, *this, AssignE, StoreE,
*NI, tag, location, val, isPrevisit);
// Update which NodeSet is the current one.
PrevSet = CurrSet;
}
// Don't autotransition. The CheckerContext objects should do this
// automatically.
}
//===----------------------------------------------------------------------===//
// Engine construction and deletion.
//===----------------------------------------------------------------------===//
static void RegisterInternalChecks(GRExprEngine &Eng) {
// Register internal "built-in" BugTypes with the BugReporter. These BugTypes
// are different than what probably many checks will do since they don't
// create BugReports on-the-fly but instead wait until GRExprEngine finishes
// analyzing a function. Generation of BugReport objects is done via a call
// to 'FlushReports' from BugReporter.
// The following checks do not need to have their associated BugTypes
// explicitly registered with the BugReporter. If they issue any BugReports,
// their associated BugType will get registered with the BugReporter
// automatically. Note that the check itself is owned by the GRExprEngine
// object.
RegisterAdjustedReturnValueChecker(Eng);
RegisterAttrNonNullChecker(Eng);
RegisterCallAndMessageChecker(Eng);
RegisterDereferenceChecker(Eng);
RegisterVLASizeChecker(Eng);
RegisterDivZeroChecker(Eng);
RegisterReturnStackAddressChecker(Eng);
RegisterReturnUndefChecker(Eng);
RegisterUndefinedArraySubscriptChecker(Eng);
RegisterUndefinedAssignmentChecker(Eng);
RegisterUndefBranchChecker(Eng);
RegisterUndefCapturedBlockVarChecker(Eng);
RegisterUndefResultChecker(Eng);
// This is not a checker yet.
RegisterNoReturnFunctionChecker(Eng);
RegisterBuiltinFunctionChecker(Eng);
RegisterOSAtomicChecker(Eng);
RegisterUnixAPIChecker(Eng);
RegisterMacOSXAPIChecker(Eng);
}
GRExprEngine::GRExprEngine(AnalysisManager &mgr, GRTransferFuncs *tf)
: AMgr(mgr),
CoreEngine(mgr.getASTContext(), *this),
G(CoreEngine.getGraph()),
Builder(NULL),
StateMgr(G.getContext(), mgr.getStoreManagerCreator(),
mgr.getConstraintManagerCreator(), G.getAllocator(),
*this),
SymMgr(StateMgr.getSymbolManager()),
ValMgr(StateMgr.getValueManager()),
SVator(ValMgr.getSValuator()),
CurrentStmt(NULL),
NSExceptionII(NULL), NSExceptionInstanceRaiseSelectors(NULL),
RaiseSel(GetNullarySelector("raise", G.getContext())),
BR(mgr, *this), TF(tf) {
// Register internal checks.
RegisterInternalChecks(*this);
// FIXME: Eventually remove the TF object entirely.
TF->RegisterChecks(*this);
TF->RegisterPrinters(getStateManager().Printers);
}
GRExprEngine::~GRExprEngine() {
BR.FlushReports();
delete [] NSExceptionInstanceRaiseSelectors;
for (CheckersOrdered::iterator I=Checkers.begin(), E=Checkers.end(); I!=E;++I)
delete I->second;
}
//===----------------------------------------------------------------------===//
// Utility methods.
//===----------------------------------------------------------------------===//
void GRExprEngine::AddCheck(GRSimpleAPICheck* A, Stmt::StmtClass C) {
if (!BatchAuditor)
BatchAuditor.reset(new MappedBatchAuditor(getGraph().getAllocator()));
((MappedBatchAuditor*) BatchAuditor.get())->AddCheck(A, C);
}
void GRExprEngine::AddCheck(GRSimpleAPICheck *A) {
if (!BatchAuditor)
BatchAuditor.reset(new MappedBatchAuditor(getGraph().getAllocator()));
((MappedBatchAuditor*) BatchAuditor.get())->AddCheck(A);
}
const GRState* GRExprEngine::getInitialState(const LocationContext *InitLoc) {
const GRState *state = StateMgr.getInitialState(InitLoc);
// Preconditions.
// FIXME: It would be nice if we had a more general mechanism to add
// such preconditions. Some day.
do {
const Decl *D = InitLoc->getDecl();
if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
// Precondition: the first argument of 'main' is an integer guaranteed
// to be > 0.
const IdentifierInfo *II = FD->getIdentifier();
if (!II || !(II->getName() == "main" && FD->getNumParams() > 0))
break;
const ParmVarDecl *PD = FD->getParamDecl(0);
QualType T = PD->getType();
if (!T->isIntegerType())
break;
const MemRegion *R = state->getRegion(PD, InitLoc);
if (!R)
break;
SVal V = state->getSVal(loc::MemRegionVal(R));
SVal Constraint_untested = EvalBinOp(state, BinaryOperator::GT, V,
ValMgr.makeZeroVal(T),
getContext().IntTy);
DefinedOrUnknownSVal *Constraint =
dyn_cast<DefinedOrUnknownSVal>(&Constraint_untested);
if (!Constraint)
break;
if (const GRState *newState = state->Assume(*Constraint, true))
state = newState;
break;
}
if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D)) {
// Precondition: 'self' is always non-null upon entry to an Objective-C
// method.
const ImplicitParamDecl *SelfD = MD->getSelfDecl();
const MemRegion *R = state->getRegion(SelfD, InitLoc);
SVal V = state->getSVal(loc::MemRegionVal(R));
if (const Loc *LV = dyn_cast<Loc>(&V)) {
// Assume that the pointer value in 'self' is non-null.
state = state->Assume(*LV, true);
assert(state && "'self' cannot be null");
}
}
} while (0);
return state;
}
//===----------------------------------------------------------------------===//
// Top-level transfer function logic (Dispatcher).
//===----------------------------------------------------------------------===//
/// EvalAssume - Called by ConstraintManager. Used to call checker-specific
/// logic for handling assumptions on symbolic values.
const GRState *GRExprEngine::ProcessAssume(const GRState *state, SVal cond,
bool assumption) {
for (CheckersOrdered::iterator I = Checkers.begin(), E = Checkers.end();
I != E; ++I) {
if (!state)
return NULL;
state = I->second->EvalAssume(state, cond, assumption);
}
if (!state)
return NULL;
return TF->EvalAssume(state, cond, assumption);
}
void GRExprEngine::ProcessStmt(CFGElement CE, GRStmtNodeBuilder& builder) {
CurrentStmt = CE.getStmt();
PrettyStackTraceLoc CrashInfo(getContext().getSourceManager(),
CurrentStmt->getLocStart(),
"Error evaluating statement");
Builder = &builder;
EntryNode = builder.getBasePredecessor();
// Set up our simple checks.
if (BatchAuditor)
Builder->setAuditor(BatchAuditor.get());
// Create the cleaned state.
const ExplodedNode *BasePred = Builder->getBasePredecessor();
SymbolReaper SymReaper(BasePred->getLocationContext(), SymMgr);
CleanedState = AMgr.shouldPurgeDead()
? StateMgr.RemoveDeadBindings(EntryNode->getState(), CurrentStmt,
BasePred->getLocationContext()->getCurrentStackFrame(),
SymReaper)
: EntryNode->getState();
// Process any special transfer function for dead symbols.
ExplodedNodeSet Tmp;
if (!SymReaper.hasDeadSymbols())
Tmp.Add(EntryNode);
else {
SaveAndRestore<bool> OldSink(Builder->BuildSinks);
SaveOr OldHasGen(Builder->HasGeneratedNode);
SaveAndRestore<bool> OldPurgeDeadSymbols(Builder->PurgingDeadSymbols);
Builder->PurgingDeadSymbols = true;
// FIXME: This should soon be removed.
ExplodedNodeSet Tmp2;
getTF().EvalDeadSymbols(Tmp2, *this, *Builder, EntryNode, CurrentStmt,
CleanedState, SymReaper);
if (Checkers.empty())
Tmp.insert(Tmp2);
else {
ExplodedNodeSet Tmp3;
ExplodedNodeSet *SrcSet = &Tmp2;
for (CheckersOrdered::iterator I = Checkers.begin(), E = Checkers.end();
I != E; ++I) {
ExplodedNodeSet *DstSet = 0;
if (I+1 == E)
DstSet = &Tmp;
else {
DstSet = (SrcSet == &Tmp2) ? &Tmp3 : &Tmp2;
DstSet->clear();
}
void *tag = I->first;
Checker *checker = I->second;
for (ExplodedNodeSet::iterator NI = SrcSet->begin(), NE = SrcSet->end();
NI != NE; ++NI)
checker->GR_EvalDeadSymbols(*DstSet, *Builder, *this, CurrentStmt,
*NI, SymReaper, tag);
SrcSet = DstSet;
}
}
if (!Builder->BuildSinks && !Builder->HasGeneratedNode)
Tmp.Add(EntryNode);
}
bool HasAutoGenerated = false;
for (ExplodedNodeSet::iterator I=Tmp.begin(), E=Tmp.end(); I!=E; ++I) {
ExplodedNodeSet Dst;
// Set the cleaned state.
Builder->SetCleanedState(*I == EntryNode ? CleanedState : GetState(*I));
// Visit the statement.
if (CE.asLValue())
VisitLValue(cast<Expr>(CurrentStmt), *I, Dst);
else
Visit(CurrentStmt, *I, Dst);
// Do we need to auto-generate a node? We only need to do this to generate
// a node with a "cleaned" state; GRCoreEngine will actually handle
// auto-transitions for other cases.
if (Dst.size() == 1 && *Dst.begin() == EntryNode
&& !Builder->HasGeneratedNode && !HasAutoGenerated) {
HasAutoGenerated = true;
builder.generateNode(CurrentStmt, GetState(EntryNode), *I);
}
}
// NULL out these variables to cleanup.
CleanedState = NULL;
EntryNode = NULL;
CurrentStmt = 0;
Builder = NULL;
}
void GRExprEngine::Visit(Stmt* S, ExplodedNode* Pred, ExplodedNodeSet& Dst) {
PrettyStackTraceLoc CrashInfo(getContext().getSourceManager(),
S->getLocStart(),
"Error evaluating statement");
// 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 && Pred->getLocationContext()->getCFG()->isBlkExpr(S)) {
Dst.Add(Pred);
return;
}
switch (S->getStmtClass()) {
// C++ stuff we don't support yet.
case Stmt::CXXMemberCallExprClass:
case Stmt::CXXNamedCastExprClass:
case Stmt::CXXStaticCastExprClass:
case Stmt::CXXDynamicCastExprClass:
case Stmt::CXXReinterpretCastExprClass:
case Stmt::CXXConstCastExprClass:
case Stmt::CXXFunctionalCastExprClass:
case Stmt::CXXTypeidExprClass:
case Stmt::CXXBoolLiteralExprClass:
case Stmt::CXXNullPtrLiteralExprClass:
case Stmt::CXXThrowExprClass:
case Stmt::CXXDefaultArgExprClass:
case Stmt::CXXZeroInitValueExprClass:
case Stmt::CXXNewExprClass:
case Stmt::CXXDeleteExprClass:
case Stmt::CXXPseudoDestructorExprClass:
case Stmt::UnresolvedLookupExprClass:
case Stmt::UnaryTypeTraitExprClass:
case Stmt::DependentScopeDeclRefExprClass:
case Stmt::CXXConstructExprClass:
case Stmt::CXXBindTemporaryExprClass:
case Stmt::CXXExprWithTemporariesClass:
case Stmt::CXXTemporaryObjectExprClass:
case Stmt::CXXUnresolvedConstructExprClass:
case Stmt::CXXDependentScopeMemberExprClass:
case Stmt::UnresolvedMemberExprClass:
case Stmt::CXXCatchStmtClass:
case Stmt::CXXTryStmtClass: {
SaveAndRestore<bool> OldSink(Builder->BuildSinks);
Builder->BuildSinks = true;
MakeNode(Dst, S, Pred, GetState(Pred));
break;
}
default:
// Cases we intentionally have "default" handle:
// AddrLabelExpr, IntegerLiteral, CharacterLiteral
Dst.Add(Pred); // No-op. Simply propagate the current state unchanged.
break;
case Stmt::ArraySubscriptExprClass:
VisitArraySubscriptExpr(cast<ArraySubscriptExpr>(S), Pred, Dst, false);
break;
case Stmt::AsmStmtClass:
VisitAsmStmt(cast<AsmStmt>(S), Pred, Dst);
break;
case Stmt::BlockDeclRefExprClass:
VisitBlockDeclRefExpr(cast<BlockDeclRefExpr>(S), Pred, Dst, false);
break;
case Stmt::BlockExprClass:
VisitBlockExpr(cast<BlockExpr>(S), Pred, Dst);
break;
case Stmt::BinaryOperatorClass: {
BinaryOperator* B = cast<BinaryOperator>(S);
if (B->isLogicalOp()) {
VisitLogicalExpr(B, Pred, Dst);
break;
}
else if (B->getOpcode() == BinaryOperator::Comma) {
const GRState* state = GetState(Pred);
MakeNode(Dst, B, Pred, state->BindExpr(B, state->getSVal(B->getRHS())));
break;
}
if (AMgr.shouldEagerlyAssume() &&
(B->isRelationalOp() || B->isEqualityOp())) {
ExplodedNodeSet Tmp;
VisitBinaryOperator(cast<BinaryOperator>(S), Pred, Tmp, false);
EvalEagerlyAssume(Dst, Tmp, cast<Expr>(S));
}
else
VisitBinaryOperator(cast<BinaryOperator>(S), Pred, Dst, false);
break;
}
case Stmt::CallExprClass:
case Stmt::CXXOperatorCallExprClass: {
CallExpr* C = cast<CallExpr>(S);
VisitCall(C, Pred, C->arg_begin(), C->arg_end(), Dst, false);
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, false);
break;
case Stmt::CompoundLiteralExprClass:
VisitCompoundLiteralExpr(cast<CompoundLiteralExpr>(S), Pred, Dst, false);
break;
case Stmt::ConditionalOperatorClass: { // '?' operator
ConditionalOperator* C = cast<ConditionalOperator>(S);
VisitGuardedExpr(C, C->getLHS(), C->getRHS(), Pred, Dst);
break;
}
case Stmt::CXXThisExprClass:
VisitCXXThisExpr(cast<CXXThisExpr>(S), Pred, Dst);
break;
case Stmt::DeclRefExprClass:
VisitDeclRefExpr(cast<DeclRefExpr>(S), Pred, Dst, false);
break;
case Stmt::DeclStmtClass:
VisitDeclStmt(cast<DeclStmt>(S), Pred, Dst);
break;
case Stmt::ForStmtClass:
// This case isn't for branch processing, but for handling the
// initialization of a condition variable.
VisitCondInit(cast<ForStmt>(S)->getConditionVariable(), S, Pred, Dst);
break;
case Stmt::ImplicitCastExprClass:
case Stmt::CStyleCastExprClass: {
CastExpr* C = cast<CastExpr>(S);
VisitCast(C, C->getSubExpr(), Pred, Dst, false);
break;
}
case Stmt::IfStmtClass:
// This case isn't for branch processing, but for handling the
// initialization of a condition variable.
VisitCondInit(cast<IfStmt>(S)->getConditionVariable(), S, Pred, Dst);
break;
case Stmt::InitListExprClass:
VisitInitListExpr(cast<InitListExpr>(S), Pred, Dst);
break;
case Stmt::MemberExprClass:
VisitMemberExpr(cast<MemberExpr>(S), Pred, Dst, false);
break;
case Stmt::ObjCIvarRefExprClass:
VisitObjCIvarRefExpr(cast<ObjCIvarRefExpr>(S), Pred, Dst, false);
break;
case Stmt::ObjCForCollectionStmtClass:
VisitObjCForCollectionStmt(cast<ObjCForCollectionStmt>(S), Pred, Dst);
break;
case Stmt::ObjCMessageExprClass:
VisitObjCMessageExpr(cast<ObjCMessageExpr>(S), Pred, Dst, false);
break;
case Stmt::ObjCAtThrowStmtClass: {
// FIXME: This is not complete. We basically treat @throw as
// an abort.
SaveAndRestore<bool> OldSink(Builder->BuildSinks);
Builder->BuildSinks = true;
MakeNode(Dst, S, Pred, GetState(Pred));
break;
}
case Stmt::ParenExprClass:
Visit(cast<ParenExpr>(S)->getSubExpr()->IgnoreParens(), Pred, Dst);
break;
case Stmt::ReturnStmtClass:
VisitReturnStmt(cast<ReturnStmt>(S), Pred, Dst);
break;
case Stmt::SizeOfAlignOfExprClass:
VisitSizeOfAlignOfExpr(cast<SizeOfAlignOfExpr>(S), Pred, Dst);
break;
case Stmt::StmtExprClass: {
StmtExpr* SE = cast<StmtExpr>(S);
if (SE->getSubStmt()->body_empty()) {
// Empty statement expression.
assert(SE->getType() == getContext().VoidTy
&& "Empty statement expression must have void type.");
Dst.Add(Pred);
break;
}
if (Expr* LastExpr = dyn_cast<Expr>(*SE->getSubStmt()->body_rbegin())) {
const GRState* state = GetState(Pred);
MakeNode(Dst, SE, Pred, state->BindExpr(SE, state->getSVal(LastExpr)));
}
else
Dst.Add(Pred);
break;
}
case Stmt::StringLiteralClass:
VisitLValue(cast<StringLiteral>(S), Pred, Dst);
break;
case Stmt::SwitchStmtClass:
// This case isn't for branch processing, but for handling the
// initialization of a condition variable.
VisitCondInit(cast<SwitchStmt>(S)->getConditionVariable(), S, Pred, Dst);
break;
case Stmt::UnaryOperatorClass: {
UnaryOperator *U = cast<UnaryOperator>(S);
if (AMgr.shouldEagerlyAssume()&&(U->getOpcode() == UnaryOperator::LNot)) {
ExplodedNodeSet Tmp;
VisitUnaryOperator(U, Pred, Tmp, false);
EvalEagerlyAssume(Dst, Tmp, U);
}
else
VisitUnaryOperator(U, Pred, Dst, false);
break;
}
case Stmt::WhileStmtClass:
// This case isn't for branch processing, but for handling the
// initialization of a condition variable.
VisitCondInit(cast<WhileStmt>(S)->getConditionVariable(), S, Pred, Dst);
break;
}
}
void GRExprEngine::VisitLValue(Expr* Ex, ExplodedNode* Pred,
ExplodedNodeSet& Dst) {
PrettyStackTraceLoc CrashInfo(getContext().getSourceManager(),
Ex->getLocStart(),
"Error evaluating statement");
Ex = Ex->IgnoreParens();
if (Ex != CurrentStmt && Pred->getLocationContext()->getCFG()->isBlkExpr(Ex)){
Dst.Add(Pred);
return;
}
switch (Ex->getStmtClass()) {
// C++ stuff we don't support yet.
case Stmt::CXXExprWithTemporariesClass:
case Stmt::CXXMemberCallExprClass:
case Stmt::CXXZeroInitValueExprClass: {
SaveAndRestore<bool> OldSink(Builder->BuildSinks);
Builder->BuildSinks = true;
MakeNode(Dst, Ex, Pred, GetState(Pred));
break;
}
case Stmt::ArraySubscriptExprClass:
VisitArraySubscriptExpr(cast<ArraySubscriptExpr>(Ex), Pred, Dst, true);
return;
case Stmt::BinaryOperatorClass:
case Stmt::CompoundAssignOperatorClass:
VisitBinaryOperator(cast<BinaryOperator>(Ex), Pred, Dst, true);
return;
case Stmt::BlockDeclRefExprClass:
VisitBlockDeclRefExpr(cast<BlockDeclRefExpr>(Ex), Pred, Dst, true);
return;
case Stmt::CallExprClass:
case Stmt::CXXOperatorCallExprClass: {
CallExpr *C = cast<CallExpr>(Ex);
assert(CalleeReturnsReferenceOrRecord(C));
VisitCall(C, Pred, C->arg_begin(), C->arg_end(), Dst, true);
break;
}
case Stmt::CompoundLiteralExprClass:
VisitCompoundLiteralExpr(cast<CompoundLiteralExpr>(Ex), Pred, Dst, true);
return;
case Stmt::DeclRefExprClass:
VisitDeclRefExpr(cast<DeclRefExpr>(Ex), Pred, Dst, true);
return;
case Stmt::ImplicitCastExprClass:
case Stmt::CStyleCastExprClass: {
CastExpr *C = cast<CastExpr>(Ex);
QualType T = Ex->getType();
VisitCast(C, C->getSubExpr(), Pred, Dst, true);
break;
}
case Stmt::MemberExprClass:
VisitMemberExpr(cast<MemberExpr>(Ex), Pred, Dst, true);
return;
case Stmt::ObjCIvarRefExprClass:
VisitObjCIvarRefExpr(cast<ObjCIvarRefExpr>(Ex), Pred, Dst, true);
return;
case Stmt::ObjCMessageExprClass: {
ObjCMessageExpr *ME = cast<ObjCMessageExpr>(Ex);
assert(ReceiverReturnsReferenceOrRecord(ME));
VisitObjCMessageExpr(ME, Pred, Dst, true);
return;
}
case Stmt::ObjCPropertyRefExprClass:
case Stmt::ObjCImplicitSetterGetterRefExprClass:
// FIXME: Property assignments are lvalues, but not really "locations".
// e.g.: self.x = something;
// Here the "self.x" really can translate to a method call (setter) when
// the assignment is made. Moreover, the entire assignment expression
// evaluate to whatever "something" is, not calling the "getter" for
// the property (which would make sense since it can have side effects).
// We'll probably treat this as a location, but not one that we can
// take the address of. Perhaps we need a new SVal class for cases
// like thsis?
// Note that we have a similar problem for bitfields, since they don't
// have "locations" in the sense that we can take their address.
Dst.Add(Pred);
return;
case Stmt::StringLiteralClass: {
const GRState* state = GetState(Pred);
SVal V = state->getLValue(cast<StringLiteral>(Ex));
MakeNode(Dst, Ex, Pred, state->BindExpr(Ex, V));
return;
}
case Stmt::UnaryOperatorClass:
VisitUnaryOperator(cast<UnaryOperator>(Ex), Pred, Dst, true);
return;
// In C++, binding an rvalue to a reference requires to create an object.
case Stmt::IntegerLiteralClass:
CreateCXXTemporaryObject(Ex, Pred, Dst);
return;
default:
// Arbitrary subexpressions can return aggregate temporaries that
// can be used in a lvalue context. We need to enhance our support
// of such temporaries in both the environment and the store, so right
// now we just do a regular visit.
assert ((Ex->getType()->isAggregateType()) &&
"Other kinds of expressions with non-aggregate/union types do"
" not have lvalues.");
Visit(Ex, Pred, Dst);
}
}
//===----------------------------------------------------------------------===//
// Block entrance. (Update counters).
//===----------------------------------------------------------------------===//
bool GRExprEngine::ProcessBlockEntrance(CFGBlock* B, const ExplodedNode *Pred,
GRBlockCounter BC) {
return BC.getNumVisited(Pred->getLocationContext()->getCurrentStackFrame(),
B->getBlockID()) < 3;
}
//===----------------------------------------------------------------------===//
// Generic node creation.
//===----------------------------------------------------------------------===//
ExplodedNode* GRExprEngine::MakeNode(ExplodedNodeSet& Dst, Stmt* S,
ExplodedNode* Pred, const GRState* St,
ProgramPoint::Kind K, const void *tag) {
assert (Builder && "GRStmtNodeBuilder not present.");
SaveAndRestore<const void*> OldTag(Builder->Tag);
Builder->Tag = tag;
return Builder->MakeNode(Dst, S, Pred, St, K);
}
//===----------------------------------------------------------------------===//
// Branch processing.
//===----------------------------------------------------------------------===//
const GRState* GRExprEngine::MarkBranch(const GRState* state,
Stmt* Terminator,
bool branchTaken) {
switch (Terminator->getStmtClass()) {
default:
return state;
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 state->BindExpr(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 state->BindExpr(C, UndefinedVal(Ex));
}
case Stmt::ChooseExprClass: { // ?:
ChooseExpr* C = cast<ChooseExpr>(Terminator);
Expr* Ex = branchTaken ? C->getLHS() : C->getRHS();
return state->BindExpr(C, UndefinedVal(Ex));
}
}
}
/// RecoverCastedSymbol - A helper function for ProcessBranch that is used
/// to try to recover some path-sensitivity for casts of symbolic
/// integers that promote their values (which are currently not tracked well).
/// This function returns the SVal bound to Condition->IgnoreCasts if all the
// cast(s) did was sign-extend the original value.
static SVal RecoverCastedSymbol(GRStateManager& StateMgr, const GRState* state,
Stmt* Condition, ASTContext& Ctx) {
Expr *Ex = dyn_cast<Expr>(Condition);
if (!Ex)
return UnknownVal();
uint64_t bits = 0;
bool bitsInit = false;
while (CastExpr *CE = dyn_cast<CastExpr>(Ex)) {
QualType T = CE->getType();
if (!T->isIntegerType())
return UnknownVal();
uint64_t newBits = Ctx.getTypeSize(T);
if (!bitsInit || newBits < bits) {
bitsInit = true;
bits = newBits;
}
Ex = CE->getSubExpr();
}
// We reached a non-cast. Is it a symbolic value?
QualType T = Ex->getType();
if (!bitsInit || !T->isIntegerType() || Ctx.getTypeSize(T) > bits)
return UnknownVal();
return state->getSVal(Ex);
}
void GRExprEngine::ProcessBranch(Stmt* Condition, Stmt* Term,
GRBranchNodeBuilder& builder) {
// Check for NULL conditions; e.g. "for(;;)"
if (!Condition) {
builder.markInfeasible(false);
return;
}
PrettyStackTraceLoc CrashInfo(getContext().getSourceManager(),
Condition->getLocStart(),
"Error evaluating branch");
for (CheckersOrdered::iterator I=Checkers.begin(),E=Checkers.end();I!=E;++I) {
void *tag = I->first;
Checker *checker = I->second;
checker->VisitBranchCondition(builder, *this, Condition, tag);
}
// If the branch condition is undefined, return;
if (!builder.isFeasible(true) && !builder.isFeasible(false))
return;
const GRState* PrevState = builder.getState();
SVal X = PrevState->getSVal(Condition);
if (X.isUnknown()) {
// Give it a chance to recover from unknown.
if (const Expr *Ex = dyn_cast<Expr>(Condition)) {
if (Ex->getType()->isIntegerType()) {
// Try to recover some path-sensitivity. Right now casts of symbolic
// integers that promote their values are currently not tracked well.
// If 'Condition' is such an expression, try and recover the
// underlying value and use that instead.
SVal recovered = RecoverCastedSymbol(getStateManager(),
builder.getState(), Condition,
getContext());
if (!recovered.isUnknown()) {
X = recovered;
}
}
}
// If the condition is still unknown, give up.
if (X.isUnknown()) {
builder.generateNode(MarkBranch(PrevState, Term, true), true);
builder.generateNode(MarkBranch(PrevState, Term, false), false);
return;
}
}
DefinedSVal V = cast<DefinedSVal>(X);
// Process the true branch.
if (builder.isFeasible(true)) {
if (const GRState *state = PrevState->Assume(V, true))
builder.generateNode(MarkBranch(state, Term, true), true);
else
builder.markInfeasible(true);
}
// Process the false branch.
if (builder.isFeasible(false)) {
if (const GRState *state = PrevState->Assume(V, false))
builder.generateNode(MarkBranch(state, 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(GRIndirectGotoNodeBuilder& builder) {
const GRState *state = builder.getState();
SVal V = state->getSVal(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 GRIndirectGotoNodeBuilder::iterator iterator;
if (isa<loc::GotoLabel>(V)) {
LabelStmt* L = cast<loc::GotoLabel>(V).getLabel();
for (iterator I=builder.begin(), E=builder.end(); I != E; ++I) {
if (I.getLabel() == L) {
builder.generateNode(I, state);
return;
}
}
assert (false && "No block with label.");
return;
}
if (isa<loc::ConcreteInt>(V) || isa<UndefinedVal>(V)) {
// Dispatch to the first target and mark it as a sink.
//ExplodedNode* N = builder.generateNode(builder.begin(), state, true);
// FIXME: add checker visit.
// UndefBranches.insert(N);
return;
}
// This is really a catch-all. We don't support symbolics yet.
// FIXME: Implement dispatch for symbolic pointers.
for (iterator I=builder.begin(), E=builder.end(); I != E; ++I)
builder.generateNode(I, state);
}
void GRExprEngine::VisitGuardedExpr(Expr* Ex, Expr* L, Expr* R,
ExplodedNode* Pred, ExplodedNodeSet& Dst) {
assert(Ex == CurrentStmt &&
Pred->getLocationContext()->getCFG()->isBlkExpr(Ex));
const GRState* state = GetState(Pred);
SVal X = state->getSVal(Ex);
assert (X.isUndef());
Expr *SE = (Expr*) cast<UndefinedVal>(X).getData();
assert(SE);
X = state->getSVal(SE);
// Make sure that we invalidate the previous binding.
MakeNode(Dst, Ex, Pred, state->BindExpr(Ex, X, true));
}
/// ProcessEndPath - Called by GRCoreEngine. Used to generate end-of-path
/// nodes when the control reaches the end of a function.
void GRExprEngine::ProcessEndPath(GREndPathNodeBuilder& builder) {
getTF().EvalEndPath(*this, builder);
StateMgr.EndPath(builder.getState());
for (CheckersOrdered::iterator I=Checkers.begin(),E=Checkers.end(); I!=E;++I){
void *tag = I->first;
Checker *checker = I->second;
checker->EvalEndPath(builder, tag, *this);
}
}
/// ProcessSwitch - Called by GRCoreEngine. Used to generate successor
/// nodes by processing the 'effects' of a switch statement.
void GRExprEngine::ProcessSwitch(GRSwitchNodeBuilder& builder) {
typedef GRSwitchNodeBuilder::iterator iterator;
const GRState* state = builder.getState();
Expr* CondE = builder.getCondition();
SVal CondV_untested = state->getSVal(CondE);
if (CondV_untested.isUndef()) {
//ExplodedNode* N = builder.generateDefaultCaseNode(state, true);
// FIXME: add checker
//UndefBranches.insert(N);
return;
}
DefinedOrUnknownSVal CondV = cast<DefinedOrUnknownSVal>(CondV_untested);
const GRState *DefaultSt = state;
bool defaultIsFeasible = false;
for (iterator I = builder.begin(), EI = builder.end(); I != EI; ++I) {
CaseStmt* Case = cast<CaseStmt>(I.getCase());
// Evaluate the LHS of the case value.
Expr::EvalResult V1;
bool b = Case->getLHS()->Evaluate(V1, getContext());
// Sanity checks. These go away in Release builds.
assert(b && V1.Val.isInt() && !V1.HasSideEffects
&& "Case condition must evaluate to an integer constant.");
b = b; // silence unused variable warning
assert(V1.Val.getInt().getBitWidth() ==
getContext().getTypeSize(CondE->getType()));
// Get the RHS of the case, if it exists.
Expr::EvalResult V2;
if (Expr* E = Case->getRHS()) {
b = E->Evaluate(V2, getContext());
assert(b && V2.Val.isInt() && !V2.HasSideEffects
&& "Case condition must evaluate to an integer constant.");
b = b; // silence unused variable warning
}
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 {
nonloc::ConcreteInt CaseVal(getBasicVals().getValue(V1.Val.getInt()));
DefinedOrUnknownSVal Res = SVator.EvalEQ(DefaultSt ? DefaultSt : state,
CondV, CaseVal);
// Now "assume" that the case matches.
if (const GRState* stateNew = state->Assume(Res, true)) {
builder.generateCaseStmtNode(I, stateNew);
// 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<nonloc::ConcreteInt>(CondV))
return;
}
// Now "assume" that the case doesn't match. Add this state
// to the default state (if it is feasible).
if (DefaultSt) {
if (const GRState *stateNew = DefaultSt->Assume(Res, false)) {
defaultIsFeasible = true;
DefaultSt = stateNew;
}
else {
defaultIsFeasible = false;
DefaultSt = NULL;
}
}
// Concretize the next value in the range.
if (V1.Val.getInt() == V2.Val.getInt())
break;
++V1.Val.getInt();
assert (V1.Val.getInt() <= V2.Val.getInt());
} while (true);
}
// If we reach here, than we know that the default branch is
// possible.
if (defaultIsFeasible) builder.generateDefaultCaseNode(DefaultSt);
}
void GRExprEngine::ProcessCallEnter(GRCallEnterNodeBuilder &B) {
const FunctionDecl *FD = B.getCallee();
const StackFrameContext *LocCtx = AMgr.getStackFrame(FD,
B.getLocationContext(),
B.getCallExpr(),
B.getBlock(),
B.getIndex());
const GRState *state = B.getState();
state = getStoreManager().EnterStackFrame(state, LocCtx);
B.GenerateNode(state, LocCtx);
}
void GRExprEngine::ProcessCallExit(GRCallExitNodeBuilder &B) {
const GRState *state = B.getState();
const ExplodedNode *Pred = B.getPredecessor();
const StackFrameContext *LocCtx =
cast<StackFrameContext>(Pred->getLocationContext());
const Stmt *CE = LocCtx->getCallSite();
// If the callee returns an expression, bind its value to CallExpr.
const Stmt *ReturnedExpr = state->get<ReturnExpr>();
if (ReturnedExpr) {
SVal RetVal = state->getSVal(ReturnedExpr);
state = state->BindExpr(CE, RetVal);
// Clear the return expr GDM.
state = state->remove<ReturnExpr>();
}
// Bind the constructed object value to CXXConstructExpr.
if (const CXXConstructExpr *CCE = dyn_cast<CXXConstructExpr>(CE)) {
const CXXThisRegion *ThisR = getCXXThisRegion(CCE, LocCtx);
// We might not have 'this' region in the binding if we didn't inline
// the ctor call.
SVal ThisV = state->getSVal(ThisR);
loc::MemRegionVal *V = dyn_cast<loc::MemRegionVal>(&ThisV);
if (V) {
SVal ObjVal = state->getSVal(V->getRegion());
assert(isa<nonloc::LazyCompoundVal>(ObjVal));
state = state->BindExpr(CCE, ObjVal);
}
}
B.GenerateNode(state);
}
//===----------------------------------------------------------------------===//
// Transfer functions: logical operations ('&&', '||').
//===----------------------------------------------------------------------===//
void GRExprEngine::VisitLogicalExpr(BinaryOperator* B, ExplodedNode* Pred,
ExplodedNodeSet& Dst) {
assert(B->getOpcode() == BinaryOperator::LAnd ||
B->getOpcode() == BinaryOperator::LOr);
assert(B==CurrentStmt && Pred->getLocationContext()->getCFG()->isBlkExpr(B));
const GRState* state = GetState(Pred);
SVal X = state->getSVal(B);
assert(X.isUndef());
const Expr *Ex = (const Expr*) cast<UndefinedVal>(X).getData();
assert(Ex);
if (Ex == B->getRHS()) {
X = state->getSVal(Ex);
// Handle undefined values.
if (X.isUndef()) {
MakeNode(Dst, B, Pred, state->BindExpr(B, X));
return;
}
DefinedOrUnknownSVal XD = cast<DefinedOrUnknownSVal>(X);
// 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.
if (const GRState *newState = state->Assume(XD, true))
MakeNode(Dst, B, Pred,
newState->BindExpr(B, ValMgr.makeIntVal(1U, B->getType())));
if (const GRState *newState = state->Assume(XD, false))
MakeNode(Dst, B, Pred,
newState->BindExpr(B, ValMgr.makeIntVal(0U, B->getType())));
}
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 = ValMgr.makeIntVal(B->getOpcode() == BinaryOperator::LAnd ? 0U : 1U,
B->getType());
MakeNode(Dst, B, Pred, state->BindExpr(B, X));
}
}
//===----------------------------------------------------------------------===//
// Transfer functions: Loads and stores.
//===----------------------------------------------------------------------===//
void GRExprEngine::VisitBlockExpr(BlockExpr *BE, ExplodedNode *Pred,
ExplodedNodeSet &Dst) {
ExplodedNodeSet Tmp;
CanQualType T = getContext().getCanonicalType(BE->getType());
SVal V = ValMgr.getBlockPointer(BE->getBlockDecl(), T,
Pred->getLocationContext());
MakeNode(Tmp, BE, Pred, GetState(Pred)->BindExpr(BE, V),
ProgramPoint::PostLValueKind);
// Post-visit the BlockExpr.
CheckerVisit(BE, Dst, Tmp, false);
}
void GRExprEngine::VisitDeclRefExpr(DeclRefExpr *Ex, ExplodedNode *Pred,
ExplodedNodeSet &Dst, bool asLValue) {
VisitCommonDeclRefExpr(Ex, Ex->getDecl(), Pred, Dst, asLValue);
}
void GRExprEngine::VisitBlockDeclRefExpr(BlockDeclRefExpr *Ex,
ExplodedNode *Pred,
ExplodedNodeSet &Dst, bool asLValue) {
VisitCommonDeclRefExpr(Ex, Ex->getDecl(), Pred, Dst, asLValue);
}
void GRExprEngine::VisitCommonDeclRefExpr(Expr *Ex, const NamedDecl *D,
ExplodedNode *Pred,
ExplodedNodeSet &Dst, bool asLValue) {
const GRState *state = GetState(Pred);
if (const VarDecl* VD = dyn_cast<VarDecl>(D)) {
SVal V = state->getLValue(VD, Pred->getLocationContext());
if (asLValue) {
// For references, the 'lvalue' is the pointer address stored in the
// reference region.
if (VD->getType()->isReferenceType()) {
if (const MemRegion *R = V.getAsRegion())
V = state->getSVal(R);
else
V = UnknownVal();
}
MakeNode(Dst, Ex, Pred, state->BindExpr(Ex, V),
ProgramPoint::PostLValueKind);
}
else
EvalLoad(Dst, Ex, Pred, state, V);
return;
} else if (const EnumConstantDecl* ED = dyn_cast<EnumConstantDecl>(D)) {
assert(!asLValue && "EnumConstantDecl does not have lvalue.");
SVal V = ValMgr.makeIntVal(ED->getInitVal());
MakeNode(Dst, Ex, Pred, state->BindExpr(Ex, V));
return;
} else if (const FunctionDecl* FD = dyn_cast<FunctionDecl>(D)) {
// This code is valid regardless of the value of 'isLValue'.
SVal V = ValMgr.getFunctionPointer(FD);
MakeNode(Dst, Ex, Pred, state->BindExpr(Ex, V),
ProgramPoint::PostLValueKind);
return;
}
assert (false &&
"ValueDecl support for this ValueDecl not implemented.");
}
/// VisitArraySubscriptExpr - Transfer function for array accesses
void GRExprEngine::VisitArraySubscriptExpr(ArraySubscriptExpr* A,
ExplodedNode* Pred,
ExplodedNodeSet& Dst, bool asLValue){
Expr* Base = A->getBase()->IgnoreParens();
Expr* Idx = A->getIdx()->IgnoreParens();
ExplodedNodeSet Tmp;
if (Base->getType()->isVectorType()) {
// For vector types get its lvalue.
// FIXME: This may not be correct. Is the rvalue of a vector its location?
// In fact, I think this is just a hack. We need to get the right
// semantics.
VisitLValue(Base, Pred, Tmp);
}
else
Visit(Base, Pred, Tmp); // Get Base's rvalue, which should be an LocVal.
for (ExplodedNodeSet::iterator I1=Tmp.begin(), E1=Tmp.end(); I1!=E1; ++I1) {
ExplodedNodeSet Tmp2;
Visit(Idx, *I1, Tmp2); // Evaluate the index.
ExplodedNodeSet Tmp3;
CheckerVisit(A, Tmp3, Tmp2, true);
for (ExplodedNodeSet::iterator I2=Tmp3.begin(),E2=Tmp3.end();I2!=E2; ++I2) {
const GRState* state = GetState(*I2);
SVal V = state->getLValue(A->getType(), state->getSVal(Idx),
state->getSVal(Base));
if (asLValue)
MakeNode(Dst, A, *I2, state->BindExpr(A, V),
ProgramPoint::PostLValueKind);
else
EvalLoad(Dst, A, *I2, state, V);
}
}
}
/// VisitMemberExpr - Transfer function for member expressions.
void GRExprEngine::VisitMemberExpr(MemberExpr* M, ExplodedNode* Pred,
ExplodedNodeSet& Dst, bool asLValue) {
Expr* Base = M->getBase()->IgnoreParens();
ExplodedNodeSet Tmp;
if (M->isArrow())
Visit(Base, Pred, Tmp); // p->f = ... or ... = p->f
else
VisitLValue(Base, Pred, Tmp); // x.f = ... or ... = x.f
FieldDecl *Field = dyn_cast<FieldDecl>(M->getMemberDecl());
if (!Field) // FIXME: skipping member expressions for non-fields
return;
for (ExplodedNodeSet::iterator I = Tmp.begin(), E = Tmp.end(); I != E; ++I) {
const GRState* state = GetState(*I);
// FIXME: Should we insert some assumption logic in here to determine
// if "Base" is a valid piece of memory? Before we put this assumption
// later when using FieldOffset lvals (which we no longer have).
SVal L = state->getLValue(Field, state->getSVal(Base));
if (asLValue)
MakeNode(Dst, M, *I, state->BindExpr(M, L), ProgramPoint::PostLValueKind);
else
EvalLoad(Dst, M, *I, state, L);
}
}
/// EvalBind - Handle the semantics of binding a value to a specific location.
/// This method is used by EvalStore and (soon) VisitDeclStmt, and others.
void GRExprEngine::EvalBind(ExplodedNodeSet& Dst, Stmt *AssignE,
Stmt* StoreE, ExplodedNode* Pred,
const GRState* state, SVal location, SVal Val,
bool atDeclInit) {
// Do a previsit of the bind.
ExplodedNodeSet CheckedSet, Src;
Src.Add(Pred);
CheckerVisitBind(AssignE, StoreE, CheckedSet, Src, location, Val, true);
for (ExplodedNodeSet::iterator I = CheckedSet.begin(), E = CheckedSet.end();
I!=E; ++I) {
if (Pred != *I)
state = GetState(*I);
const GRState* newState = 0;
if (atDeclInit) {
const VarRegion *VR =
cast<VarRegion>(cast<loc::MemRegionVal>(location).getRegion());
newState = state->bindDecl(VR, Val);
}
else {
if (location.isUnknown()) {
// We know that the new state will be the same as the old state since
// the location of the binding is "unknown". Consequently, there
// is no reason to just create a new node.
newState = state;
}
else {
// We are binding to a value other than 'unknown'. Perform the binding
// using the StoreManager.
newState = state->bindLoc(cast<Loc>(location), Val);
}
}
// The next thing to do is check if the GRTransferFuncs object wants to
// update the state based on the new binding. If the GRTransferFunc object
// doesn't do anything, just auto-propagate the current state.
GRStmtNodeBuilderRef BuilderRef(Dst, *Builder, *this, *I, newState, StoreE,
newState != state);
getTF().EvalBind(BuilderRef, location, Val);
}
}
/// EvalStore - Handle the semantics of a store via an assignment.
/// @param Dst The node set to store generated state nodes
/// @param Ex The expression representing the location of the store
/// @param state The current simulation state
/// @param location The location to store the value
/// @param Val The value to be stored
void GRExprEngine::EvalStore(ExplodedNodeSet& Dst, Expr *AssignE,
Expr* StoreE,
ExplodedNode* Pred,
const GRState* state, SVal location, SVal Val,
const void *tag) {
assert(Builder && "GRStmtNodeBuilder must be defined.");
// Evaluate the location (checks for bad dereferences).
ExplodedNodeSet Tmp;
EvalLocation(Tmp, StoreE, Pred, state, location, tag, false);
if (Tmp.empty())
return;
assert(!location.isUndef());
SaveAndRestore<ProgramPoint::Kind> OldSPointKind(Builder->PointKind,
ProgramPoint::PostStoreKind);
SaveAndRestore<const void*> OldTag(Builder->Tag, tag);
// Proceed with the store.
for (ExplodedNodeSet::iterator NI=Tmp.begin(), NE=Tmp.end(); NI!=NE; ++NI)
EvalBind(Dst, AssignE, StoreE, *NI, GetState(*NI), location, Val);
}
void GRExprEngine::EvalLoad(ExplodedNodeSet& Dst, Expr *Ex, ExplodedNode* Pred,
const GRState* state, SVal location,
const void *tag, QualType LoadTy) {
// Are we loading from a region? This actually results in two loads; one
// to fetch the address of the referenced value and one to fetch the
// referenced value.
if (const TypedRegion *TR =
dyn_cast_or_null<TypedRegion>(location.getAsRegion())) {
QualType ValTy = TR->getValueType(getContext());
if (const ReferenceType *RT = ValTy->getAs<ReferenceType>()) {
static int loadReferenceTag = 0;
ExplodedNodeSet Tmp;
EvalLoadCommon(Tmp, Ex, Pred, state, location, &loadReferenceTag,
getContext().getPointerType(RT->getPointeeType()));
// Perform the load from the referenced value.
for (ExplodedNodeSet::iterator I=Tmp.begin(), E=Tmp.end() ; I!=E; ++I) {
state = GetState(*I);
location = state->getSVal(Ex);
EvalLoadCommon(Dst, Ex, *I, state, location, tag, LoadTy);
}
return;
}
}
EvalLoadCommon(Dst, Ex, Pred, state, location, tag, LoadTy);
}
void GRExprEngine::EvalLoadCommon(ExplodedNodeSet& Dst, Expr *Ex,
ExplodedNode* Pred,
const GRState* state, SVal location,
const void *tag, QualType LoadTy) {
// Evaluate the location (checks for bad dereferences).
ExplodedNodeSet Tmp;
EvalLocation(Tmp, Ex, Pred, state, location, tag, true);
if (Tmp.empty())
return;
assert(!location.isUndef());
SaveAndRestore<ProgramPoint::Kind> OldSPointKind(Builder->PointKind);
SaveAndRestore<const void*> OldTag(Builder->Tag);
// Proceed with the load.
for (ExplodedNodeSet::iterator NI=Tmp.begin(), NE=Tmp.end(); NI!=NE; ++NI) {
state = GetState(*NI);
if (location.isUnknown()) {
// This is important. We must nuke the old binding.
MakeNode(Dst, Ex, *NI, state->BindExpr(Ex, UnknownVal()),
ProgramPoint::PostLoadKind, tag);
}
else {
SVal V = state->getSVal(cast<Loc>(location), LoadTy.isNull() ?
Ex->getType() : LoadTy);
MakeNode(Dst, Ex, *NI, state->BindExpr(Ex, V), ProgramPoint::PostLoadKind,
tag);
}
}
}
void GRExprEngine::EvalLocation(ExplodedNodeSet &Dst, Stmt *S,
ExplodedNode* Pred,
const GRState* state, SVal location,
const void *tag, bool isLoad) {
// Early checks for performance reason.
if (location.isUnknown() || Checkers.empty()) {
Dst.Add(Pred);
return;
}
ExplodedNodeSet Src, Tmp;
Src.Add(Pred);
ExplodedNodeSet *PrevSet = &Src;
for (CheckersOrdered::iterator I=Checkers.begin(),E=Checkers.end(); I!=E; ++I)
{
ExplodedNodeSet *CurrSet = 0;
if (I+1 == E)
CurrSet = &Dst;
else {
CurrSet = (PrevSet == &Tmp) ? &Src : &Tmp;
CurrSet->clear();
}
void *tag = I->first;
Checker *checker = I->second;
for (ExplodedNodeSet::iterator NI = PrevSet->begin(), NE = PrevSet->end();
NI != NE; ++NI) {
// Use the 'state' argument only when the predecessor node is the
// same as Pred. This allows us to catch updates to the state.
checker->GR_VisitLocation(*CurrSet, *Builder, *this, S, *NI,
*NI == Pred ? state : GetState(*NI),
location, tag, isLoad);
}
// Update which NodeSet is the current one.
PrevSet = CurrSet;
}
}
//===----------------------------------------------------------------------===//
// Transfer function: Function calls.
//===----------------------------------------------------------------------===//
namespace {
class CallExprWLItem {
public:
CallExpr::arg_iterator I;
ExplodedNode *N;
CallExprWLItem(const CallExpr::arg_iterator &i, ExplodedNode *n)
: I(i), N(n) {}
};
} // end anonymous namespace
void GRExprEngine::VisitCall(CallExpr* CE, ExplodedNode* Pred,
CallExpr::arg_iterator AI,
CallExpr::arg_iterator AE,
ExplodedNodeSet& Dst, bool asLValue) {
// Determine the type of function we're calling (if available).
const FunctionProtoType *Proto = NULL;
QualType FnType = CE->getCallee()->IgnoreParens()->getType();
if (const PointerType *FnTypePtr = FnType->getAs<PointerType>())
Proto = FnTypePtr->getPointeeType()->getAs<FunctionProtoType>();
// Create a worklist to process the arguments.
llvm::SmallVector<CallExprWLItem, 20> WorkList;
WorkList.reserve(AE - AI);
WorkList.push_back(CallExprWLItem(AI, Pred));
ExplodedNodeSet ArgsEvaluated;
while (!WorkList.empty()) {
CallExprWLItem Item = WorkList.back();
WorkList.pop_back();
if (Item.I == AE) {
ArgsEvaluated.insert(Item.N);
continue;
}
// Evaluate the argument.
ExplodedNodeSet Tmp;
const unsigned ParamIdx = Item.I - AI;
bool VisitAsLvalue = false;
if (Proto && ParamIdx < Proto->getNumArgs())
VisitAsLvalue = Proto->getArgType(ParamIdx)->isReferenceType();
if (VisitAsLvalue)
VisitLValue(*Item.I, Item.N, Tmp);
else
Visit(*Item.I, Item.N, Tmp);
// Enqueue evaluating the next argument on the worklist.
++(Item.I);
for (ExplodedNodeSet::iterator NI=Tmp.begin(), NE=Tmp.end(); NI!=NE; ++NI)
WorkList.push_back(CallExprWLItem(Item.I, *NI));
}
// Now process the call itself.
ExplodedNodeSet DstTmp;
Expr* Callee = CE->getCallee()->IgnoreParens();
for (ExplodedNodeSet::iterator NI=ArgsEvaluated.begin(),
NE=ArgsEvaluated.end(); NI != NE; ++NI) {
// Evaluate the callee.
ExplodedNodeSet DstTmp2;
Visit(Callee, *NI, DstTmp2);
// Perform the previsit of the CallExpr, storing the results in DstTmp.
CheckerVisit(CE, DstTmp, DstTmp2, true);
}
// Finally, evaluate the function call. We try each of the checkers
// to see if the can evaluate the function call.
ExplodedNodeSet DstTmp3;
for (ExplodedNodeSet::iterator DI = DstTmp.begin(), DE = DstTmp.end();
DI != DE; ++DI) {
const GRState* state = GetState(*DI);
SVal L = state->getSVal(Callee);
// FIXME: Add support for symbolic function calls (calls involving
// function pointer values that are symbolic).
SaveAndRestore<bool> OldSink(Builder->BuildSinks);
ExplodedNodeSet DstChecker;
// If the callee is processed by a checker, skip the rest logic.
if (CheckerEvalCall(CE, DstChecker, *DI))
DstTmp3.insert(DstChecker);
else {
for (ExplodedNodeSet::iterator DI_Checker = DstChecker.begin(),
DE_Checker = DstChecker.end();
DI_Checker != DE_Checker; ++DI_Checker) {
// Dispatch to the plug-in transfer function.
unsigned OldSize = DstTmp3.size();
SaveOr OldHasGen(Builder->HasGeneratedNode);
Pred = *DI_Checker;
// Dispatch to transfer function logic to handle the call itself.
// FIXME: Allow us to chain together transfer functions.
assert(Builder && "GRStmtNodeBuilder must be defined.");
getTF().EvalCall(DstTmp3, *this, *Builder, CE, L, Pred);
// Handle the case where no nodes where generated. Auto-generate that
// contains the updated state if we aren't generating sinks.
if (!Builder->BuildSinks && DstTmp3.size() == OldSize &&
!Builder->HasGeneratedNode)
MakeNode(DstTmp3, CE, Pred, state);
}
}
}
// Finally, perform the post-condition check of the CallExpr and store
// the created nodes in 'Dst'.
if (!(!asLValue && CalleeReturnsReference(CE))) {
CheckerVisit(CE, Dst, DstTmp3, false);
return;
}
// Handle the case where the called function returns a reference but
// we expect an rvalue. For such cases, convert the reference to
// an rvalue.
// FIXME: This conversion doesn't actually happen unless the result
// of CallExpr is consumed by another expression.
ExplodedNodeSet DstTmp4;
CheckerVisit(CE, DstTmp4, DstTmp3, false);
QualType LoadTy = CE->getType();
static int *ConvertToRvalueTag = 0;
for (ExplodedNodeSet::iterator NI = DstTmp4.begin(), NE = DstTmp4.end();
NI!=NE; ++NI) {
const GRState *state = GetState(*NI);
EvalLoad(Dst, CE, *NI, state, state->getSVal(CE),
&ConvertToRvalueTag, LoadTy);
}
}
//===----------------------------------------------------------------------===//
// Transfer function: Objective-C ivar references.
//===----------------------------------------------------------------------===//
static std::pair<const void*,const void*> EagerlyAssumeTag
= std::pair<const void*,const void*>(&EagerlyAssumeTag,0);
void GRExprEngine::EvalEagerlyAssume(ExplodedNodeSet &Dst, ExplodedNodeSet &Src,
Expr *Ex) {
for (ExplodedNodeSet::iterator I=Src.begin(), E=Src.end(); I!=E; ++I) {
ExplodedNode *Pred = *I;
// Test if the previous node was as the same expression. This can happen
// when the expression fails to evaluate to anything meaningful and
// (as an optimization) we don't generate a node.
ProgramPoint P = Pred->getLocation();
if (!isa<PostStmt>(P) || cast<PostStmt>(P).getStmt() != Ex) {
Dst.Add(Pred);
continue;
}
const GRState* state = Pred->getState();
SVal V = state->getSVal(Ex);
if (nonloc::SymExprVal *SEV = dyn_cast<nonloc::SymExprVal>(&V)) {
// First assume that the condition is true.
if (const GRState *stateTrue = state->Assume(*SEV, true)) {
stateTrue = stateTrue->BindExpr(Ex,
ValMgr.makeIntVal(1U, Ex->getType()));
Dst.Add(Builder->generateNode(PostStmtCustom(Ex,
&EagerlyAssumeTag, Pred->getLocationContext()),
stateTrue, Pred));
}
// Next, assume that the condition is false.
if (const GRState *stateFalse = state->Assume(*SEV, false)) {
stateFalse = stateFalse->BindExpr(Ex,
ValMgr.makeIntVal(0U, Ex->getType()));
Dst.Add(Builder->generateNode(PostStmtCustom(Ex, &EagerlyAssumeTag,
Pred->getLocationContext()),
stateFalse, Pred));
}
}
else
Dst.Add(Pred);
}
}
//===----------------------------------------------------------------------===//
// Transfer function: Objective-C ivar references.
//===----------------------------------------------------------------------===//
void GRExprEngine::VisitObjCIvarRefExpr(ObjCIvarRefExpr* Ex, ExplodedNode* Pred,
ExplodedNodeSet& Dst, bool asLValue) {
Expr* Base = cast<Expr>(Ex->getBase());
ExplodedNodeSet Tmp;
Visit(Base, Pred, Tmp);
for (ExplodedNodeSet::iterator I=Tmp.begin(), E=Tmp.end(); I!=E; ++I) {
const GRState* state = GetState(*I);
SVal BaseVal = state->getSVal(Base);
SVal location = state->getLValue(Ex->getDecl(), BaseVal);
if (asLValue)
MakeNode(Dst, Ex, *I, state->BindExpr(Ex, location));
else
EvalLoad(Dst, Ex, *I, state, location);
}
}
//===----------------------------------------------------------------------===//
// Transfer function: Objective-C fast enumeration 'for' statements.
//===----------------------------------------------------------------------===//
void GRExprEngine::VisitObjCForCollectionStmt(ObjCForCollectionStmt* S,
ExplodedNode* Pred, ExplodedNodeSet& Dst) {
// ObjCForCollectionStmts are processed in two places. This method
// handles the case where an ObjCForCollectionStmt* occurs as one of the
// statements within a basic block. This transfer function does two things:
//
// (1) binds the next container value to 'element'. This creates a new
// node in the ExplodedGraph.
//
// (2) binds the value 0/1 to the ObjCForCollectionStmt* itself, indicating
// whether or not the container has any more elements. This value
// will be tested in ProcessBranch. We need to explicitly bind
// this value because a container can contain nil elements.
//
// FIXME: Eventually this logic should actually do dispatches to
// 'countByEnumeratingWithState:objects:count:' (NSFastEnumeration).
// This will require simulating a temporary NSFastEnumerationState, either
// through an SVal or through the use of MemRegions. This value can
// be affixed to the ObjCForCollectionStmt* instead of 0/1; when the loop
// terminates we reclaim the temporary (it goes out of scope) and we
// we can test if the SVal is 0 or if the MemRegion is null (depending
// on what approach we take).
//
// For now: simulate (1) by assigning either a symbol or nil if the
// container is empty. Thus this transfer function will by default
// result in state splitting.
Stmt* elem = S->getElement();
SVal ElementV;
if (DeclStmt* DS = dyn_cast<DeclStmt>(elem)) {
VarDecl* ElemD = cast<VarDecl>(DS->getSingleDecl());
assert (ElemD->getInit() == 0);
ElementV = GetState(Pred)->getLValue(ElemD, Pred->getLocationContext());
VisitObjCForCollectionStmtAux(S, Pred, Dst, ElementV);
return;
}
ExplodedNodeSet Tmp;
VisitLValue(cast<Expr>(elem), Pred, Tmp);
for (ExplodedNodeSet::iterator I = Tmp.begin(), E = Tmp.end(); I!=E; ++I) {
const GRState* state = GetState(*I);
VisitObjCForCollectionStmtAux(S, *I, Dst, state->getSVal(elem));
}
}
void GRExprEngine::VisitObjCForCollectionStmtAux(ObjCForCollectionStmt* S,
ExplodedNode* Pred, ExplodedNodeSet& Dst,
SVal ElementV) {
// Check if the location we are writing back to is a null pointer.
Stmt* elem = S->getElement();
ExplodedNodeSet Tmp;
EvalLocation(Tmp, elem, Pred, GetState(Pred), ElementV, NULL, false);
if (Tmp.empty())
return;
for (ExplodedNodeSet::iterator NI=Tmp.begin(), NE=Tmp.end(); NI!=NE; ++NI) {
Pred = *NI;
const GRState *state = GetState(Pred);
// Handle the case where the container still has elements.
SVal TrueV = ValMgr.makeTruthVal(1);
const GRState *hasElems = state->BindExpr(S, TrueV);
// Handle the case where the container has no elements.
SVal FalseV = ValMgr.makeTruthVal(0);
const GRState *noElems = state->BindExpr(S, FalseV);
if (loc::MemRegionVal* MV = dyn_cast<loc::MemRegionVal>(&ElementV))
if (const TypedRegion* R = dyn_cast<TypedRegion>(MV->getRegion())) {
// FIXME: The proper thing to do is to really iterate over the
// container. We will do this with dispatch logic to the store.
// For now, just 'conjure' up a symbolic value.
QualType T = R->getValueType(getContext());
assert(Loc::IsLocType(T));
unsigned Count = Builder->getCurrentBlockCount();
SymbolRef Sym = SymMgr.getConjuredSymbol(elem, T, Count);
SVal V = ValMgr.makeLoc(Sym);
hasElems = hasElems->bindLoc(ElementV, V);
// Bind the location to 'nil' on the false branch.
SVal nilV = ValMgr.makeIntVal(0, T);
noElems = noElems->bindLoc(ElementV, nilV);
}
// Create the new nodes.
MakeNode(Dst, S, Pred, hasElems);
MakeNode(Dst, S, Pred, noElems);
}
}
//===----------------------------------------------------------------------===//
// Transfer function: Objective-C message expressions.
//===----------------------------------------------------------------------===//
namespace {
class ObjCMsgWLItem {
public:
ObjCMessageExpr::arg_iterator I;
ExplodedNode *N;
ObjCMsgWLItem(const ObjCMessageExpr::arg_iterator &i, ExplodedNode *n)
: I(i), N(n) {}
};
} // end anonymous namespace
void GRExprEngine::VisitObjCMessageExpr(ObjCMessageExpr* ME, ExplodedNode* Pred,
ExplodedNodeSet& Dst, bool asLValue){
// Create a worklist to process both the arguments.
llvm::SmallVector<ObjCMsgWLItem, 20> WL;
// But first evaluate the receiver (if any).
ObjCMessageExpr::arg_iterator AI = ME->arg_begin(), AE = ME->arg_end();
if (Expr *Receiver = ME->getReceiver()) {
ExplodedNodeSet Tmp;
Visit(Receiver, Pred, Tmp);
if (Tmp.empty())
return;
for (ExplodedNodeSet::iterator I=Tmp.begin(), E=Tmp.end(); I!=E; ++I)
WL.push_back(ObjCMsgWLItem(AI, *I));
}
else
WL.push_back(ObjCMsgWLItem(AI, Pred));
// Evaluate the arguments.
ExplodedNodeSet ArgsEvaluated;
while (!WL.empty()) {
ObjCMsgWLItem Item = WL.back();
WL.pop_back();
if (Item.I == AE) {
ArgsEvaluated.insert(Item.N);
continue;
}
// Evaluate the subexpression.
ExplodedNodeSet Tmp;
// FIXME: [Objective-C++] handle arguments that are references
Visit(*Item.I, Item.N, Tmp);
// Enqueue evaluating the next argument on the worklist.
++(Item.I);
for (ExplodedNodeSet::iterator NI=Tmp.begin(), NE=Tmp.end(); NI!=NE; ++NI)
WL.push_back(ObjCMsgWLItem(Item.I, *NI));
}
// Now that the arguments are processed, handle the previsits checks.
ExplodedNodeSet DstPrevisit;
CheckerVisit(ME, DstPrevisit, ArgsEvaluated, true);
// Proceed with evaluate the message expression.
ExplodedNodeSet DstEval;
for (ExplodedNodeSet::iterator DI = DstPrevisit.begin(),
DE = DstPrevisit.end(); DI != DE; ++DI) {
Pred = *DI;
bool RaisesException = false;
unsigned OldSize = DstEval.size();
SaveAndRestore<bool> OldSink(Builder->BuildSinks);
SaveOr OldHasGen(Builder->HasGeneratedNode);
if (const Expr *Receiver = ME->getReceiver()) {
const GRState *state = Pred->getState();
// Bifurcate the state into nil and non-nil ones.
DefinedOrUnknownSVal receiverVal =
cast<DefinedOrUnknownSVal>(state->getSVal(Receiver));
const GRState *notNilState, *nilState;
llvm::tie(notNilState, nilState) = state->Assume(receiverVal);
// There are three cases: can be nil or non-nil, must be nil, must be
// non-nil. We handle must be nil, and merge the rest two into non-nil.
if (nilState && !notNilState) {
CheckerEvalNilReceiver(ME, DstEval, nilState, Pred);
continue;
}
// Check if the "raise" message was sent.
assert(notNilState);
if (ME->getSelector() == RaiseSel)
RaisesException = true;
// Check if we raise an exception. For now treat these as sinks.
// Eventually we will want to handle exceptions properly.
if (RaisesException)
Builder->BuildSinks = true;
// Dispatch to plug-in transfer function.
EvalObjCMessageExpr(DstEval, ME, Pred, notNilState);
}
else {
IdentifierInfo* ClsName = ME->getClassName();
Selector S = ME->getSelector();
// Check for special instance methods.
if (!NSExceptionII) {
ASTContext& Ctx = getContext();
NSExceptionII = &Ctx.Idents.get("NSException");
}
if (ClsName == NSExceptionII) {
enum { NUM_RAISE_SELECTORS = 2 };
// Lazily create a cache of the selectors.
if (!NSExceptionInstanceRaiseSelectors) {
ASTContext& Ctx = getContext();
NSExceptionInstanceRaiseSelectors =
new Selector[NUM_RAISE_SELECTORS];
llvm::SmallVector<IdentifierInfo*, NUM_RAISE_SELECTORS> II;
unsigned idx = 0;
// raise:format:
II.push_back(&Ctx.Idents.get("raise"));
II.push_back(&Ctx.Idents.get("format"));
NSExceptionInstanceRaiseSelectors[idx++] =
Ctx.Selectors.getSelector(II.size(), &II[0]);
// raise:format::arguments:
II.push_back(&Ctx.Idents.get("arguments"));
NSExceptionInstanceRaiseSelectors[idx++] =
Ctx.Selectors.getSelector(II.size(), &II[0]);
}
for (unsigned i = 0; i < NUM_RAISE_SELECTORS; ++i)
if (S == NSExceptionInstanceRaiseSelectors[i]) {
RaisesException = true;
break;
}
}
// Check if we raise an exception. For now treat these as sinks.
// Eventually we will want to handle exceptions properly.
if (RaisesException)
Builder->BuildSinks = true;
// Dispatch to plug-in transfer function.
EvalObjCMessageExpr(DstEval, ME, Pred, Builder->GetState(Pred));
}
// Handle the case where no nodes where generated. Auto-generate that
// contains the updated state if we aren't generating sinks.
if (!Builder->BuildSinks && DstEval.size() == OldSize &&
!Builder->HasGeneratedNode)
MakeNode(DstEval, ME, Pred, GetState(Pred));
}
// Finally, perform the post-condition check of the ObjCMessageExpr and store
// the created nodes in 'Dst'.
if (!(!asLValue && ReceiverReturnsReference(ME))) {
CheckerVisit(ME, Dst, DstEval, false);
return;
}
// Handle the case where the message expression returns a reference but
// we expect an rvalue. For such cases, convert the reference to
// an rvalue.
// FIXME: This conversion doesn't actually happen unless the result
// of ObjCMessageExpr is consumed by another expression.
ExplodedNodeSet DstRValueConvert;
CheckerVisit(ME, DstRValueConvert, DstEval, false);
QualType LoadTy = ME->getType();
static int *ConvertToRvalueTag = 0;
for (ExplodedNodeSet::iterator NI = DstRValueConvert.begin(),
NE = DstRValueConvert.end(); NI != NE; ++NI) {
const GRState *state = GetState(*NI);
EvalLoad(Dst, ME, *NI, state, state->getSVal(ME),
&ConvertToRvalueTag, LoadTy);
}
}
//===----------------------------------------------------------------------===//
// Transfer functions: Miscellaneous statements.
//===----------------------------------------------------------------------===//
void GRExprEngine::VisitCast(CastExpr *CastE, Expr *Ex, ExplodedNode *Pred,
ExplodedNodeSet &Dst, bool asLValue) {
ExplodedNodeSet S1;
QualType T = CastE->getType();
QualType ExTy = Ex->getType();
if (const ExplicitCastExpr *ExCast=dyn_cast_or_null<ExplicitCastExpr>(CastE))
T = ExCast->getTypeAsWritten();
if (ExTy->isArrayType() || ExTy->isFunctionType() || T->isReferenceType() ||
asLValue)
VisitLValue(Ex, Pred, S1);
else
Visit(Ex, Pred, S1);
ExplodedNodeSet S2;
CheckerVisit(CastE, S2, S1, true);
// If we are evaluating the cast in an lvalue context, we implicitly want
// the cast to evaluate to a location.
if (asLValue) {
ASTContext &Ctx = getContext();
T = Ctx.getPointerType(Ctx.getCanonicalType(T));
ExTy = Ctx.getPointerType(Ctx.getCanonicalType(ExTy));
}
switch (CastE->getCastKind()) {
case CastExpr::CK_ToVoid:
assert(!asLValue);
for (ExplodedNodeSet::iterator I = S2.begin(), E = S2.end(); I != E; ++I)
Dst.Add(*I);
return;
case CastExpr::CK_NoOp:
case CastExpr::CK_FunctionToPointerDecay:
for (ExplodedNodeSet::iterator I = S2.begin(), E = S2.end(); I != E; ++I) {
// Copy the SVal of Ex to CastE.
ExplodedNode *N = *I;
const GRState *state = GetState(N);
SVal V = state->getSVal(Ex);
state = state->BindExpr(CastE, V);
MakeNode(Dst, CastE, N, state);
}
return;
case CastExpr::CK_Unknown:
case CastExpr::CK_ArrayToPointerDecay:
case CastExpr::CK_BitCast:
case CastExpr::CK_IntegralCast:
case CastExpr::CK_IntegralToPointer:
case CastExpr::CK_PointerToIntegral:
case CastExpr::CK_IntegralToFloating:
case CastExpr::CK_FloatingToIntegral:
case CastExpr::CK_FloatingCast:
case CastExpr::CK_AnyPointerToObjCPointerCast:
case CastExpr::CK_AnyPointerToBlockPointerCast:
case CastExpr::CK_DerivedToBase:
// Delegate to SValuator to process.
for (ExplodedNodeSet::iterator I = S2.begin(), E = S2.end(); I != E; ++I) {
ExplodedNode* N = *I;
const GRState* state = GetState(N);
SVal V = state->getSVal(Ex);
V = SVator.EvalCast(V, T, ExTy);
state = state->BindExpr(CastE, V);
MakeNode(Dst, CastE, N, state);
}
return;
default:
llvm::errs() << "Cast kind " << CastE->getCastKind() << " not handled.\n";
assert(0);
}
}
void GRExprEngine::VisitCompoundLiteralExpr(CompoundLiteralExpr* CL,
ExplodedNode* Pred,
ExplodedNodeSet& Dst,
bool asLValue) {
InitListExpr* ILE = cast<InitListExpr>(CL->getInitializer()->IgnoreParens());
ExplodedNodeSet Tmp;
Visit(ILE, Pred, Tmp);
for (ExplodedNodeSet::iterator I = Tmp.begin(), EI = Tmp.end(); I!=EI; ++I) {
const GRState* state = GetState(*I);
SVal ILV = state->getSVal(ILE);
const LocationContext *LC = (*I)->getLocationContext();
state = state->bindCompoundLiteral(CL, LC, ILV);
if (asLValue) {
MakeNode(Dst, CL, *I, state->BindExpr(CL, state->getLValue(CL, LC)));
}
else
MakeNode(Dst, CL, *I, state->BindExpr(CL, ILV));
}
}
void GRExprEngine::VisitDeclStmt(DeclStmt *DS, ExplodedNode *Pred,
ExplodedNodeSet& Dst) {
// The CFG has one DeclStmt per Decl.
Decl* D = *DS->decl_begin();
if (!D || !isa<VarDecl>(D))
return;
const VarDecl* VD = dyn_cast<VarDecl>(D);
Expr* InitEx = const_cast<Expr*>(VD->getInit());
// FIXME: static variables may have an initializer, but the second
// time a function is called those values may not be current.
ExplodedNodeSet Tmp;
if (InitEx) {
if (const CXXConstructExpr *E = dyn_cast<CXXConstructExpr>(InitEx)) {
VisitCXXConstructExpr(E, GetState(Pred)->getLValue(VD,
Pred->getLocationContext()), Pred, Dst);
return;
} else if (VD->getType()->isReferenceType())
VisitLValue(InitEx, Pred, Tmp);
else
Visit(InitEx, Pred, Tmp);
}
else
Tmp.Add(Pred);
ExplodedNodeSet Tmp2;
CheckerVisit(DS, Tmp2, Tmp, true);
for (ExplodedNodeSet::iterator I=Tmp2.begin(), E=Tmp2.end(); I!=E; ++I) {
ExplodedNode *N = *I;
const GRState *state = GetState(N);
// Decls without InitExpr are not initialized explicitly.
const LocationContext *LC = N->getLocationContext();
if (InitEx) {
SVal InitVal = state->getSVal(InitEx);
// Recover some path-sensitivity if a scalar value evaluated to
// UnknownVal.
if ((InitVal.isUnknown() ||
!getConstraintManager().canReasonAbout(InitVal)) &&
!VD->getType()->isReferenceType()) {
InitVal = ValMgr.getConjuredSymbolVal(NULL, InitEx,
Builder->getCurrentBlockCount());
}
EvalBind(Dst, DS, DS, *I, state,
loc::MemRegionVal(state->getRegion(VD, LC)), InitVal, true);
}
else {
state = state->bindDeclWithNoInit(state->getRegion(VD, LC));
MakeNode(Dst, DS, *I, state);
}
}
}
void GRExprEngine::VisitCondInit(VarDecl *VD, Stmt *S,
ExplodedNode *Pred, ExplodedNodeSet& Dst) {
Expr* InitEx = VD->getInit();
ExplodedNodeSet Tmp;
Visit(InitEx, Pred, Tmp);
for (ExplodedNodeSet::iterator I=Tmp.begin(), E=Tmp.end(); I!=E; ++I) {
ExplodedNode *N = *I;
const GRState *state = GetState(N);
const LocationContext *LC = N->getLocationContext();
SVal InitVal = state->getSVal(InitEx);
// Recover some path-sensitivity if a scalar value evaluated to
// UnknownVal.
if (InitVal.isUnknown() ||
!getConstraintManager().canReasonAbout(InitVal)) {
InitVal = ValMgr.getConjuredSymbolVal(NULL, InitEx,
Builder->getCurrentBlockCount());
}
EvalBind(Dst, S, S, N, state,
loc::MemRegionVal(state->getRegion(VD, LC)), InitVal, true);
}
}
namespace {
// This class is used by VisitInitListExpr as an item in a worklist
// for processing the values contained in an InitListExpr.
class InitListWLItem {
public:
llvm::ImmutableList<SVal> Vals;
ExplodedNode* N;
InitListExpr::reverse_iterator Itr;
InitListWLItem(ExplodedNode* n, llvm::ImmutableList<SVal> vals,
InitListExpr::reverse_iterator itr)
: Vals(vals), N(n), Itr(itr) {}
};
}
void GRExprEngine::VisitInitListExpr(InitListExpr* E, ExplodedNode* Pred,
ExplodedNodeSet& Dst) {
const GRState* state = GetState(Pred);
QualType T = getContext().getCanonicalType(E->getType());
unsigned NumInitElements = E->getNumInits();
if (T->isArrayType() || T->isStructureType() ||
T->isUnionType() || T->isVectorType()) {
llvm::ImmutableList<SVal> StartVals = getBasicVals().getEmptySValList();
// Handle base case where the initializer has no elements.
// e.g: static int* myArray[] = {};
if (NumInitElements == 0) {
SVal V = ValMgr.makeCompoundVal(T, StartVals);
MakeNode(Dst, E, Pred, state->BindExpr(E, V));
return;
}
// Create a worklist to process the initializers.
llvm::SmallVector<InitListWLItem, 10> WorkList;
WorkList.reserve(NumInitElements);
WorkList.push_back(InitListWLItem(Pred, StartVals, E->rbegin()));
InitListExpr::reverse_iterator ItrEnd = E->rend();
assert(!(E->rbegin() == E->rend()));
// Process the worklist until it is empty.
while (!WorkList.empty()) {
InitListWLItem X = WorkList.back();
WorkList.pop_back();
ExplodedNodeSet Tmp;
Visit(*X.Itr, X.N, Tmp);
InitListExpr::reverse_iterator NewItr = X.Itr + 1;
for (ExplodedNodeSet::iterator NI=Tmp.begin(),NE=Tmp.end();NI!=NE;++NI) {
// Get the last initializer value.
state = GetState(*NI);
SVal InitV = state->getSVal(cast<Expr>(*X.Itr));
// Construct the new list of values by prepending the new value to
// the already constructed list.
llvm::ImmutableList<SVal> NewVals =
getBasicVals().consVals(InitV, X.Vals);
if (NewItr == ItrEnd) {
// Now we have a list holding all init values. Make CompoundValData.
SVal V = ValMgr.makeCompoundVal(T, NewVals);
// Make final state and node.
MakeNode(Dst, E, *NI, state->BindExpr(E, V));
}
else {
// Still some initializer values to go. Push them onto the worklist.
WorkList.push_back(InitListWLItem(*NI, NewVals, NewItr));
}
}
}
return;
}
if (Loc::IsLocType(T) || T->isIntegerType()) {
assert (E->getNumInits() == 1);
ExplodedNodeSet Tmp;
Expr* Init = E->getInit(0);
Visit(Init, Pred, Tmp);
for (ExplodedNodeSet::iterator I=Tmp.begin(), EI=Tmp.end(); I != EI; ++I) {
state = GetState(*I);
MakeNode(Dst, E, *I, state->BindExpr(E, state->getSVal(Init)));
}
return;
}
assert(0 && "unprocessed InitListExpr type");
}
/// VisitSizeOfAlignOfExpr - Transfer function for sizeof(type).
void GRExprEngine::VisitSizeOfAlignOfExpr(SizeOfAlignOfExpr* Ex,
ExplodedNode* Pred,
ExplodedNodeSet& Dst) {
QualType T = Ex->getTypeOfArgument();
CharUnits amt;
if (Ex->isSizeOf()) {
if (T == getContext().VoidTy) {
// sizeof(void) == 1 byte.
amt = CharUnits::One();
}
else if (!T.getTypePtr()->isConstantSizeType()) {
// FIXME: Add support for VLAs.
Dst.Add(Pred);
return;
}
else if (T->isObjCInterfaceType()) {
// Some code tries to take the sizeof an ObjCInterfaceType, relying that
// the compiler has laid out its representation. Just report Unknown
// for these.
Dst.Add(Pred);
return;
}
else {
// All other cases.
amt = getContext().getTypeSizeInChars(T);
}
}
else // Get alignment of the type.
amt = getContext().getTypeAlignInChars(T);
MakeNode(Dst, Ex, Pred,
GetState(Pred)->BindExpr(Ex,
ValMgr.makeIntVal(amt.getQuantity(), Ex->getType())));
}
void GRExprEngine::VisitUnaryOperator(UnaryOperator* U, ExplodedNode* Pred,
ExplodedNodeSet& Dst, bool asLValue) {
switch (U->getOpcode()) {
default:
break;
case UnaryOperator::Deref: {
Expr* Ex = U->getSubExpr()->IgnoreParens();
ExplodedNodeSet Tmp;
Visit(Ex, Pred, Tmp);
for (ExplodedNodeSet::iterator I=Tmp.begin(), E=Tmp.end(); I!=E; ++I) {
const GRState* state = GetState(*I);
SVal location = state->getSVal(Ex);
if (asLValue)
MakeNode(Dst, U, *I, state->BindExpr(U, location),
ProgramPoint::PostLValueKind);
else
EvalLoad(Dst, U, *I, state, location);
}
return;
}
case UnaryOperator::Real: {
Expr* Ex = U->getSubExpr()->IgnoreParens();
ExplodedNodeSet Tmp;
Visit(Ex, Pred, Tmp);
for (ExplodedNodeSet::iterator I=Tmp.begin(), E=Tmp.end(); I!=E; ++I) {
// FIXME: We don't have complex SValues yet.
if (Ex->getType()->isAnyComplexType()) {
// Just report "Unknown."
Dst.Add(*I);
continue;
}
// For all other types, UnaryOperator::Real is an identity operation.
assert (U->getType() == Ex->getType());
const GRState* state = GetState(*I);
MakeNode(Dst, U, *I, state->BindExpr(U, state->getSVal(Ex)));
}
return;
}
case UnaryOperator::Imag: {
Expr* Ex = U->getSubExpr()->IgnoreParens();
ExplodedNodeSet Tmp;
Visit(Ex, Pred, Tmp);
for (ExplodedNodeSet::iterator I=Tmp.begin(), E=Tmp.end(); I!=E; ++I) {
// FIXME: We don't have complex SValues yet.
if (Ex->getType()->isAnyComplexType()) {
// Just report "Unknown."
Dst.Add(*I);
continue;
}
// For all other types, UnaryOperator::Float returns 0.
assert (Ex->getType()->isIntegerType());
const GRState* state = GetState(*I);
SVal X = ValMgr.makeZeroVal(Ex->getType());
MakeNode(Dst, U, *I, state->BindExpr(U, X));
}
return;
}
case UnaryOperator::OffsetOf: {
Expr::EvalResult Res;
if (U->Evaluate(Res, getContext()) && Res.Val.isInt()) {
const APSInt &IV = Res.Val.getInt();
assert(IV.getBitWidth() == getContext().getTypeSize(U->getType()));
assert(U->getType()->isIntegerType());
assert(IV.isSigned() == U->getType()->isSignedIntegerType());
SVal X = ValMgr.makeIntVal(IV);
MakeNode(Dst, U, Pred, GetState(Pred)->BindExpr(U, X));
return;
}
// FIXME: Handle the case where __builtin_offsetof is not a constant.
Dst.Add(Pred);
return;
}
case UnaryOperator::Plus: assert (!asLValue); // FALL-THROUGH.
case UnaryOperator::Extension: {
// Unary "+" is a no-op, similar to a parentheses. We still have places
// where it may be a block-level expression, so we need to
// generate an extra node that just propagates the value of the
// subexpression.
Expr* Ex = U->getSubExpr()->IgnoreParens();
ExplodedNodeSet Tmp;
Visit(Ex, Pred, Tmp);
for (ExplodedNodeSet::iterator I=Tmp.begin(), E=Tmp.end(); I!=E; ++I) {
const GRState* state = GetState(*I);
MakeNode(Dst, U, *I, state->BindExpr(U, state->getSVal(Ex)));
}
return;
}
case UnaryOperator::AddrOf: {
assert(!asLValue);
Expr* Ex = U->getSubExpr()->IgnoreParens();
ExplodedNodeSet Tmp;
VisitLValue(Ex, Pred, Tmp);
for (ExplodedNodeSet::iterator I=Tmp.begin(), E=Tmp.end(); I!=E; ++I) {
const GRState* state = GetState(*I);
SVal V = state->getSVal(Ex);
state = state->BindExpr(U, V);
MakeNode(Dst, U, *I, state);
}
return;
}
case UnaryOperator::LNot:
case UnaryOperator::Minus:
case UnaryOperator::Not: {
assert (!asLValue);
Expr* Ex = U->getSubExpr()->IgnoreParens();
ExplodedNodeSet Tmp;
Visit(Ex, Pred, Tmp);
for (ExplodedNodeSet::iterator I=Tmp.begin(), E=Tmp.end(); I!=E; ++I) {
const GRState* state = GetState(*I);
// Get the value of the subexpression.
SVal V = state->getSVal(Ex);
if (V.isUnknownOrUndef()) {
MakeNode(Dst, U, *I, state->BindExpr(U, V));
continue;
}
// QualType DstT = getContext().getCanonicalType(U->getType());
// QualType SrcT = getContext().getCanonicalType(Ex->getType());
//
// if (DstT != SrcT) // Perform promotions.
// V = EvalCast(V, DstT);
//
// if (V.isUnknownOrUndef()) {
// MakeNode(Dst, U, *I, BindExpr(St, U, V));
// continue;
// }
switch (U->getOpcode()) {
default:
assert(false && "Invalid Opcode.");
break;
case UnaryOperator::Not:
// FIXME: Do we need to handle promotions?
state = state->BindExpr(U, EvalComplement(cast<NonLoc>(V)));
break;
case UnaryOperator::Minus:
// FIXME: Do we need to handle promotions?
state = state->BindExpr(U, EvalMinus(cast<NonLoc>(V)));
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".
SVal Result;
if (isa<Loc>(V)) {
Loc X = ValMgr.makeNull();
Result = EvalBinOp(state, BinaryOperator::EQ, cast<Loc>(V), X,
U->getType());
}
else {
nonloc::ConcreteInt X(getBasicVals().getValue(0, Ex->getType()));
Result = EvalBinOp(state, BinaryOperator::EQ, cast<NonLoc>(V), X,
U->getType());
}
state = state->BindExpr(U, Result);
break;
}
MakeNode(Dst, U, *I, state);
}
return;
}
}
// Handle ++ and -- (both pre- and post-increment).
assert (U->isIncrementDecrementOp());
ExplodedNodeSet Tmp;
Expr* Ex = U->getSubExpr()->IgnoreParens();
VisitLValue(Ex, Pred, Tmp);
for (ExplodedNodeSet::iterator I = Tmp.begin(), E = Tmp.end(); I!=E; ++I) {
const GRState* state = GetState(*I);
SVal V1 = state->getSVal(Ex);
// Perform a load.
ExplodedNodeSet Tmp2;
EvalLoad(Tmp2, Ex, *I, state, V1);
for (ExplodedNodeSet::iterator I2=Tmp2.begin(), E2=Tmp2.end();I2!=E2;++I2) {
state = GetState(*I2);
SVal V2_untested = state->getSVal(Ex);
// Propagate unknown and undefined values.
if (V2_untested.isUnknownOrUndef()) {
MakeNode(Dst, U, *I2, state->BindExpr(U, V2_untested));
continue;
}
DefinedSVal V2 = cast<DefinedSVal>(V2_untested);
// Handle all other values.
BinaryOperator::Opcode Op = U->isIncrementOp() ? BinaryOperator::Add
: BinaryOperator::Sub;
// If the UnaryOperator has non-location type, use its type to create the
// constant value. If the UnaryOperator has location type, create the
// constant with int type and pointer width.
SVal RHS;
if (U->getType()->isAnyPointerType())
RHS = ValMgr.makeIntValWithPtrWidth(1, false);
else
RHS = ValMgr.makeIntVal(1, U->getType());
SVal Result = EvalBinOp(state, Op, V2, RHS, U->getType());
// Conjure a new symbol if necessary to recover precision.
if (Result.isUnknown() || !getConstraintManager().canReasonAbout(Result)){
DefinedOrUnknownSVal SymVal =
ValMgr.getConjuredSymbolVal(NULL, Ex,
Builder->getCurrentBlockCount());
Result = SymVal;
// If the value is a location, ++/-- should always preserve
// non-nullness. Check if the original value was non-null, and if so
// propagate that constraint.
if (Loc::IsLocType(U->getType())) {
DefinedOrUnknownSVal Constraint =
SVator.EvalEQ(state, V2, ValMgr.makeZeroVal(U->getType()));
if (!state->Assume(Constraint, true)) {
// It isn't feasible for the original value to be null.
// Propagate this constraint.
Constraint = SVator.EvalEQ(state, SymVal,
ValMgr.makeZeroVal(U->getType()));
state = state->Assume(Constraint, false);
assert(state);
}
}
}
state = state->BindExpr(U, U->isPostfix() ? V2 : Result);
// Perform the store.
EvalStore(Dst, NULL, U, *I2, state, V1, Result);
}
}
}
void GRExprEngine::VisitCXXThisExpr(CXXThisExpr *TE, ExplodedNode *Pred,
ExplodedNodeSet & Dst) {
// Get the this object region from StoreManager.
const MemRegion *R =
ValMgr.getRegionManager().getCXXThisRegion(
getContext().getCanonicalType(TE->getType()),
Pred->getLocationContext());
const GRState *state = GetState(Pred);
SVal V = state->getSVal(loc::MemRegionVal(R));
MakeNode(Dst, TE, Pred, state->BindExpr(TE, V));
}
void GRExprEngine::VisitAsmStmt(AsmStmt* A, ExplodedNode* Pred,
ExplodedNodeSet& Dst) {
VisitAsmStmtHelperOutputs(A, A->begin_outputs(), A->end_outputs(), Pred, Dst);
}
void GRExprEngine::VisitAsmStmtHelperOutputs(AsmStmt* A,
AsmStmt::outputs_iterator I,
AsmStmt::outputs_iterator E,
ExplodedNode* Pred, ExplodedNodeSet& Dst) {
if (I == E) {
VisitAsmStmtHelperInputs(A, A->begin_inputs(), A->end_inputs(), Pred, Dst);
return;
}
ExplodedNodeSet Tmp;
VisitLValue(*I, Pred, Tmp);
++I;
for (ExplodedNodeSet::iterator NI = Tmp.begin(), NE = Tmp.end();NI != NE;++NI)
VisitAsmStmtHelperOutputs(A, I, E, *NI, Dst);
}
void GRExprEngine::VisitAsmStmtHelperInputs(AsmStmt* A,
AsmStmt::inputs_iterator I,
AsmStmt::inputs_iterator E,
ExplodedNode* Pred,
ExplodedNodeSet& Dst) {
if (I == E) {
// We have processed both the inputs and the outputs. All of the outputs
// should evaluate to Locs. Nuke all of their values.
// FIXME: Some day in the future it would be nice to allow a "plug-in"
// which interprets the inline asm and stores proper results in the
// outputs.
const GRState* state = GetState(Pred);
for (AsmStmt::outputs_iterator OI = A->begin_outputs(),
OE = A->end_outputs(); OI != OE; ++OI) {
SVal X = state->getSVal(*OI);
assert (!isa<NonLoc>(X)); // Should be an Lval, or unknown, undef.
if (isa<Loc>(X))
state = state->bindLoc(cast<Loc>(X), UnknownVal());
}
MakeNode(Dst, A, Pred, state);
return;
}
ExplodedNodeSet Tmp;
Visit(*I, Pred, Tmp);
++I;
for (ExplodedNodeSet::iterator NI = Tmp.begin(), NE = Tmp.end(); NI!=NE; ++NI)
VisitAsmStmtHelperInputs(A, I, E, *NI, Dst);
}
void GRExprEngine::VisitReturnStmt(ReturnStmt *RS, ExplodedNode *Pred,
ExplodedNodeSet &Dst) {
ExplodedNodeSet Src;
if (Expr *RetE = RS->getRetValue()) {
// Record the returned expression in the state. It will be used in
// ProcessCallExit to bind the return value to the call expr.
{
static int Tag = 0;
SaveAndRestore<const void *> OldTag(Builder->Tag, &Tag);
const GRState *state = GetState(Pred);
state = state->set<ReturnExpr>(RetE);
Pred = Builder->generateNode(RetE, state, Pred);
}
// We may get a NULL Pred because we generated a cached node.
if (Pred)
Visit(RetE, Pred, Src);
}
else {
Src.Add(Pred);
}
ExplodedNodeSet CheckedSet;
CheckerVisit(RS, CheckedSet, Src, true);
for (ExplodedNodeSet::iterator I = CheckedSet.begin(), E = CheckedSet.end();
I != E; ++I) {
assert(Builder && "GRStmtNodeBuilder must be defined.");
Pred = *I;
unsigned size = Dst.size();
SaveAndRestore<bool> OldSink(Builder->BuildSinks);
SaveOr OldHasGen(Builder->HasGeneratedNode);
getTF().EvalReturn(Dst, *this, *Builder, RS, Pred);
// Handle the case where no nodes where generated.
if (!Builder->BuildSinks && Dst.size() == size &&
!Builder->HasGeneratedNode)
MakeNode(Dst, RS, Pred, GetState(Pred));
}
}
//===----------------------------------------------------------------------===//
// Transfer functions: Binary operators.
//===----------------------------------------------------------------------===//
void GRExprEngine::VisitBinaryOperator(BinaryOperator* B,
ExplodedNode* Pred,
ExplodedNodeSet& Dst, bool asLValue) {
ExplodedNodeSet Tmp1;
Expr* LHS = B->getLHS()->IgnoreParens();
Expr* RHS = B->getRHS()->IgnoreParens();
// FIXME: Add proper support for ObjCImplicitSetterGetterRefExpr.
if (isa<ObjCImplicitSetterGetterRefExpr>(LHS)) {
Visit(RHS, Pred, Dst);
return;
}
if (B->isAssignmentOp())
VisitLValue(LHS, Pred, Tmp1);
else
Visit(LHS, Pred, Tmp1);
ExplodedNodeSet Tmp3;
for (ExplodedNodeSet::iterator I1=Tmp1.begin(), E1=Tmp1.end(); I1!=E1; ++I1) {
SVal LeftV = (*I1)->getState()->getSVal(LHS);
ExplodedNodeSet Tmp2;
Visit(RHS, *I1, Tmp2);
ExplodedNodeSet CheckedSet;
CheckerVisit(B, CheckedSet, Tmp2, true);
// With both the LHS and RHS evaluated, process the operation itself.
for (ExplodedNodeSet::iterator I2=CheckedSet.begin(), E2=CheckedSet.end();
I2 != E2; ++I2) {
const GRState *state = GetState(*I2);
const GRState *OldSt = state;
SVal RightV = state->getSVal(RHS);
BinaryOperator::Opcode Op = B->getOpcode();
if (Op == BinaryOperator::Assign) {
// EXPERIMENTAL: "Conjured" symbols.
// FIXME: Handle structs.
QualType T = RHS->getType();
if ((RightV.isUnknown()||!getConstraintManager().canReasonAbout(RightV))
&& (Loc::IsLocType(T) || (T->isScalarType()&&T->isIntegerType()))) {
unsigned Count = Builder->getCurrentBlockCount();
RightV = ValMgr.getConjuredSymbolVal(NULL, B->getRHS(), Count);
}
SVal ExprVal = asLValue ? LeftV : RightV;
// Simulate the effects of a "store": bind the value of the RHS
// to the L-Value represented by the LHS.
EvalStore(Tmp3, B, LHS, *I2, state->BindExpr(B, ExprVal), LeftV,RightV);
continue;
}
if (!B->isAssignmentOp()) {
// Process non-assignments except commas or short-circuited
// logical expressions (LAnd and LOr).
SVal Result = EvalBinOp(state, Op, LeftV, RightV, B->getType());
if (Result.isUnknown()) {
if (OldSt != state) {
// Generate a new node if we have already created a new state.
MakeNode(Tmp3, B, *I2, state);
}
else
Tmp3.Add(*I2);
continue;
}
state = state->BindExpr(B, Result);
MakeNode(Tmp3, B, *I2, state);
continue;
}
assert (B->isCompoundAssignmentOp());
switch (Op) {
default:
assert(0 && "Invalid opcode for compound assignment.");
case BinaryOperator::MulAssign: Op = BinaryOperator::Mul; break;
case BinaryOperator::DivAssign: Op = BinaryOperator::Div; break;
case BinaryOperator::RemAssign: Op = BinaryOperator::Rem; break;
case BinaryOperator::AddAssign: Op = BinaryOperator::Add; break;
case BinaryOperator::SubAssign: Op = BinaryOperator::Sub; break;
case BinaryOperator::ShlAssign: Op = BinaryOperator::Shl; break;
case BinaryOperator::ShrAssign: Op = BinaryOperator::Shr; break;
case BinaryOperator::AndAssign: Op = BinaryOperator::And; break;
case BinaryOperator::XorAssign: Op = BinaryOperator::Xor; break;
case BinaryOperator::OrAssign: Op = BinaryOperator::Or; break;
}
// Perform a load (the LHS). This performs the checks for
// null dereferences, and so on.
ExplodedNodeSet Tmp4;
SVal location = state->getSVal(LHS);
EvalLoad(Tmp4, LHS, *I2, state, location);
for (ExplodedNodeSet::iterator I4=Tmp4.begin(), E4=Tmp4.end(); I4!=E4;
++I4) {
state = GetState(*I4);
SVal V = state->getSVal(LHS);
// Get the computation type.
QualType CTy =
cast<CompoundAssignOperator>(B)->getComputationResultType();
CTy = getContext().getCanonicalType(CTy);
QualType CLHSTy =
cast<CompoundAssignOperator>(B)->getComputationLHSType();
CLHSTy = getContext().getCanonicalType(CLHSTy);
QualType LTy = getContext().getCanonicalType(LHS->getType());
QualType RTy = getContext().getCanonicalType(RHS->getType());
// Promote LHS.
V = SVator.EvalCast(V, CLHSTy, LTy);
// Compute the result of the operation.
SVal Result = SVator.EvalCast(EvalBinOp(state, Op, V, RightV, CTy),
B->getType(), CTy);
// EXPERIMENTAL: "Conjured" symbols.
// FIXME: Handle structs.
SVal LHSVal;
if ((Result.isUnknown() ||
!getConstraintManager().canReasonAbout(Result))
&& (Loc::IsLocType(CTy)
|| (CTy->isScalarType() && CTy->isIntegerType()))) {
unsigned Count = Builder->getCurrentBlockCount();
// The symbolic value is actually for the type of the left-hand side
// expression, not the computation type, as this is the value the
// LValue on the LHS will bind to.
LHSVal = ValMgr.getConjuredSymbolVal(NULL, B->getRHS(), LTy, Count);
// However, we need to convert the symbol to the computation type.
Result = SVator.EvalCast(LHSVal, CTy, LTy);
}
else {
// The left-hand side may bind to a different value then the
// computation type.
LHSVal = SVator.EvalCast(Result, LTy, CTy);
}
EvalStore(Tmp3, B, LHS, *I4, state->BindExpr(B, Result),
location, LHSVal);
}
}
}
CheckerVisit(B, Dst, Tmp3, false);
}
void GRExprEngine::CreateCXXTemporaryObject(Expr *Ex, ExplodedNode *Pred,
ExplodedNodeSet &Dst) {
ExplodedNodeSet Tmp;
Visit(Ex, Pred, Tmp);
for (ExplodedNodeSet::iterator I = Tmp.begin(), E = Tmp.end(); I != E; ++I) {
const GRState *state = GetState(*I);
// Bind the temporary object to the value of the expression. Then bind
// the expression to the location of the object.
SVal V = state->getSVal(Ex);
const MemRegion *R =
ValMgr.getRegionManager().getCXXObjectRegion(Ex,
Pred->getLocationContext());
state = state->bindLoc(loc::MemRegionVal(R), V);
MakeNode(Dst, Ex, Pred, state->BindExpr(Ex, loc::MemRegionVal(R)));
}
}
void GRExprEngine::VisitCXXConstructExpr(const CXXConstructExpr *E, SVal Dest,
ExplodedNode *Pred,
ExplodedNodeSet &Dst) {
if (E->isElidable()) {
VisitAggExpr(E->getArg(0), Dest, Pred, Dst);
return;
}
const CXXConstructorDecl *CD = E->getConstructor();
assert(CD);
if (!CD->isThisDeclarationADefinition())
// FIXME: invalidate the object.
return;
// Evaluate other arguments.
CXXConstructExpr::arg_iterator AB
= const_cast<CXXConstructExpr*>(E)->arg_begin();
CXXConstructExpr::arg_iterator AE
= const_cast<CXXConstructExpr*>(E)->arg_end();
llvm::SmallVector<CallExprWLItem, 20> WorkList;
WorkList.reserve(AE - AB);
WorkList.push_back(CallExprWLItem(AB, Pred));
ExplodedNodeSet ArgsEvaluated;
const FunctionProtoType *Proto = CD->getType()->getAs<FunctionProtoType>();
while (!WorkList.empty()) {
CallExprWLItem Item = WorkList.back();
WorkList.pop_back();
if (Item.I == AE) {
ArgsEvaluated.insert(Item.N);
continue;
}
// Evaluate the argument.
ExplodedNodeSet Tmp;
const unsigned ParamIdx = Item.I - AB;
bool VisitAsLvalue = false;
if (ParamIdx < Proto->getNumArgs())
VisitAsLvalue = Proto->getArgType(ParamIdx)->isReferenceType();
if (VisitAsLvalue)
VisitLValue(*Item.I, Item.N, Tmp);
else
Visit(*Item.I, Item.N, Tmp);
++(Item.I);
for (ExplodedNodeSet::iterator NI=Tmp.begin(), NE=Tmp.end(); NI!=NE; ++NI)
WorkList.push_back(CallExprWLItem(Item.I, *NI));
}
// The callee stack frame context used to create the 'this' parameter region.
const StackFrameContext *SFC = AMgr.getStackFrame(CD,
Pred->getLocationContext(),
E, Builder->getBlock(), Builder->getIndex());
const CXXThisRegion *ThisR = getCXXThisRegion(E, SFC);
CallEnter Loc(E, CD, Pred->getLocationContext());
for (ExplodedNodeSet::iterator NI = ArgsEvaluated.begin(),
NE = ArgsEvaluated.end(); NI != NE; ++NI) {
const GRState *state = GetState(*NI);
// Setup 'this' region.
state = state->bindLoc(loc::MemRegionVal(ThisR), Dest);
ExplodedNode *N = Builder->generateNode(Loc, state, Pred);
if (N)
Dst.Add(N);
}
}
const CXXThisRegion *GRExprEngine::getCXXThisRegion(const CXXConstructExpr *E,
const StackFrameContext *SFC) {
Type *T = E->getConstructor()->getParent()->getTypeForDecl();
QualType PT = getContext().getPointerType(QualType(T,0));
return ValMgr.getRegionManager().getCXXThisRegion(PT, SFC);
}
//===----------------------------------------------------------------------===//
// Checker registration/lookup.
//===----------------------------------------------------------------------===//
Checker *GRExprEngine::lookupChecker(void *tag) const {
CheckerMap::const_iterator I = CheckerM.find(tag);
return (I == CheckerM.end()) ? NULL : Checkers[I->second].second;
}
//===----------------------------------------------------------------------===//
// Visualization.
//===----------------------------------------------------------------------===//
#ifndef NDEBUG
static GRExprEngine* GraphPrintCheckerState;
static SourceManager* GraphPrintSourceManager;
namespace llvm {
template<>
struct DOTGraphTraits<ExplodedNode*> :
public DefaultDOTGraphTraits {
DOTGraphTraits (bool isSimple=false) : DefaultDOTGraphTraits(isSimple) {}
// FIXME: Since we do not cache error nodes in GRExprEngine now, this does not
// work.
static std::string getNodeAttributes(const ExplodedNode* N, void*) {
#if 0
// FIXME: Replace with a general scheme to tell if the node is
// an error node.
if (GraphPrintCheckerState->isImplicitNullDeref(N) ||
GraphPrintCheckerState->isExplicitNullDeref(N) ||
GraphPrintCheckerState->isUndefDeref(N) ||
GraphPrintCheckerState->isUndefStore(N) ||
GraphPrintCheckerState->isUndefControlFlow(N) ||
GraphPrintCheckerState->isUndefResult(N) ||
GraphPrintCheckerState->isBadCall(N) ||
GraphPrintCheckerState->isUndefArg(N))
return "color=\"red\",style=\"filled\"";
if (GraphPrintCheckerState->isNoReturnCall(N))
return "color=\"blue\",style=\"filled\"";
#endif
return "";
}
static std::string getNodeLabel(const ExplodedNode* N, void*){
std::string sbuf;
llvm::raw_string_ostream Out(sbuf);
// 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::CallEnterKind:
Out << "CallEnter";
break;
case ProgramPoint::CallExitKind:
Out << "CallExit";
break;
default: {
if (StmtPoint *L = dyn_cast<StmtPoint>(&Loc)) {
const Stmt* S = L->getStmt();
SourceLocation SLoc = S->getLocStart();
Out << S->getStmtClassName() << ' ' << (void*) S << ' ';
LangOptions LO; // FIXME.
S->printPretty(Out, 0, PrintingPolicy(LO));
if (SLoc.isFileID()) {
Out << "\\lline="
<< GraphPrintSourceManager->getInstantiationLineNumber(SLoc)
<< " col="
<< GraphPrintSourceManager->getInstantiationColumnNumber(SLoc)
<< "\\l";
}
if (isa<PreStmt>(Loc))
Out << "\\lPreStmt\\l;";
else if (isa<PostLoad>(Loc))
Out << "\\lPostLoad\\l;";
else if (isa<PostStore>(Loc))
Out << "\\lPostStore\\l";
else if (isa<PostLValue>(Loc))
Out << "\\lPostLValue\\l";
#if 0
// FIXME: Replace with a general scheme to determine
// the name of the check.
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 Loc.";
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";
#endif
break;
}
const BlockEdge& E = cast<BlockEdge>(Loc);
Out << "Edge: (B" << E.getSrc()->getBlockID() << ", B"
<< E.getDst()->getBlockID() << ')';
if (Stmt* T = E.getSrc()->getTerminator()) {
SourceLocation SLoc = T->getLocStart();
Out << "\\|Terminator: ";
LangOptions LO; // FIXME.
E.getSrc()->printTerminator(Out, LO);
if (SLoc.isFileID()) {
Out << "\\lline="
<< GraphPrintSourceManager->getInstantiationLineNumber(SLoc)
<< " col="
<< GraphPrintSourceManager->getInstantiationColumnNumber(SLoc);
}
if (isa<SwitchStmt>(T)) {
Stmt* Label = E.getDst()->getLabel();
if (Label) {
if (CaseStmt* C = dyn_cast<CaseStmt>(Label)) {
Out << "\\lcase ";
LangOptions LO; // FIXME.
C->getLHS()->printPretty(Out, 0, PrintingPolicy(LO));
if (Stmt* RHS = C->getRHS()) {
Out << " .. ";
RHS->printPretty(Out, 0, PrintingPolicy(LO));
}
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 0
// FIXME: Replace with a general scheme to determine
// the name of the check.
if (GraphPrintCheckerState->isUndefControlFlow(N)) {
Out << "\\|Control-flow based on\\lUndefined value.\\l";
}
#endif
}
}
Out << "\\|StateID: " << (void*) N->getState() << "\\|";
const GRState *state = N->getState();
state->printDOT(Out, *N->getLocationContext()->getCFG());
Out << "\\l";
return Out.str();
}
};
} // end llvm namespace
#endif
#ifndef NDEBUG
template <typename ITERATOR>
ExplodedNode* GetGraphNode(ITERATOR I) { return *I; }
template <> ExplodedNode*
GetGraphNode<llvm::DenseMap<ExplodedNode*, Expr*>::iterator>
(llvm::DenseMap<ExplodedNode*, Expr*>::iterator I) {
return I->first;
}
#endif
void GRExprEngine::ViewGraph(bool trim) {
#ifndef NDEBUG
if (trim) {
std::vector<ExplodedNode*> Src;
// Flush any outstanding reports to make sure we cover all the nodes.
// This does not cause them to get displayed.
for (BugReporter::iterator I=BR.begin(), E=BR.end(); I!=E; ++I)
const_cast<BugType*>(*I)->FlushReports(BR);
// Iterate through the reports and get their nodes.
for (BugReporter::iterator I=BR.begin(), E=BR.end(); I!=E; ++I) {
for (BugType::const_iterator I2=(*I)->begin(), E2=(*I)->end();
I2!=E2; ++I2) {
const BugReportEquivClass& EQ = *I2;
const BugReport &R = **EQ.begin();
ExplodedNode *N = const_cast<ExplodedNode*>(R.getEndNode());
if (N) Src.push_back(N);
}
}
ViewGraph(&Src[0], &Src[0]+Src.size());
}
else {
GraphPrintCheckerState = this;
GraphPrintSourceManager = &getContext().getSourceManager();
llvm::ViewGraph(*G.roots_begin(), "GRExprEngine");
GraphPrintCheckerState = NULL;
GraphPrintSourceManager = NULL;
}
#endif
}
void GRExprEngine::ViewGraph(ExplodedNode** Beg, ExplodedNode** End) {
#ifndef NDEBUG
GraphPrintCheckerState = this;
GraphPrintSourceManager = &getContext().getSourceManager();
std::auto_ptr<ExplodedGraph> TrimmedG(G.Trim(Beg, End).first);
if (!TrimmedG.get())
llvm::errs() << "warning: Trimmed ExplodedGraph is empty.\n";
else
llvm::ViewGraph(*TrimmedG->roots_begin(), "TrimmedGRExprEngine");
GraphPrintCheckerState = NULL;
GraphPrintSourceManager = NULL;
#endif
}
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