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//=-- ExprEngine.cpp - Path-Sensitive Expression-Level Dataflow ---*- C++ -*-=
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines a meta-engine for path-sensitive dataflow analysis that
// is built on GREngine, but provides the boilerplate to execute transfer
// functions and build the ExplodedGraph at the expression level.
//
//===----------------------------------------------------------------------===//
#include "clang/StaticAnalyzer/Core/PathSensitive/ExprEngine.h"
#include "PrettyStackTraceLocationContext.h"
#include "clang/AST/CharUnits.h"
#include "clang/AST/ParentMap.h"
#include "clang/AST/StmtCXX.h"
#include "clang/AST/StmtObjC.h"
#include "clang/Basic/Builtins.h"
#include "clang/Basic/PrettyStackTrace.h"
#include "clang/Basic/SourceManager.h"
#include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
#include "clang/StaticAnalyzer/Core/CheckerManager.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/AnalysisManager.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/LoopWidening.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Support/SaveAndRestore.h"
#include "llvm/Support/raw_ostream.h"
#ifndef NDEBUG
#include "llvm/Support/GraphWriter.h"
#endif
using namespace clang;
using namespace ento;
using llvm::APSInt;
#define DEBUG_TYPE "ExprEngine"
STATISTIC(NumRemoveDeadBindings,
"The # of times RemoveDeadBindings is called");
STATISTIC(NumMaxBlockCountReached,
"The # of aborted paths due to reaching the maximum block count in "
"a top level function");
STATISTIC(NumMaxBlockCountReachedInInlined,
"The # of aborted paths due to reaching the maximum block count in "
"an inlined function");
STATISTIC(NumTimesRetriedWithoutInlining,
"The # of times we re-evaluated a call without inlining");
typedef std::pair<const CXXBindTemporaryExpr *, const StackFrameContext *>
CXXBindTemporaryContext;
// Keeps track of whether CXXBindTemporaryExpr nodes have been evaluated.
// The StackFrameContext assures that nested calls due to inlined recursive
// functions do not interfere.
REGISTER_TRAIT_WITH_PROGRAMSTATE(InitializedTemporariesSet,
llvm::ImmutableSet<CXXBindTemporaryContext>)
//===----------------------------------------------------------------------===//
// Engine construction and deletion.
//===----------------------------------------------------------------------===//
static const char* TagProviderName = "ExprEngine";
ExprEngine::ExprEngine(AnalysisManager &mgr, bool gcEnabled,
SetOfConstDecls *VisitedCalleesIn,
FunctionSummariesTy *FS,
InliningModes HowToInlineIn)
: AMgr(mgr),
AnalysisDeclContexts(mgr.getAnalysisDeclContextManager()),
Engine(*this, FS),
G(Engine.getGraph()),
StateMgr(getContext(), mgr.getStoreManagerCreator(),
mgr.getConstraintManagerCreator(), G.getAllocator(),
this),
SymMgr(StateMgr.getSymbolManager()),
svalBuilder(StateMgr.getSValBuilder()),
currStmtIdx(0), currBldrCtx(nullptr),
ObjCNoRet(mgr.getASTContext()),
ObjCGCEnabled(gcEnabled), BR(mgr, *this),
VisitedCallees(VisitedCalleesIn),
HowToInline(HowToInlineIn)
{
unsigned TrimInterval = mgr.options.getGraphTrimInterval();
if (TrimInterval != 0) {
// Enable eager node reclaimation when constructing the ExplodedGraph.
G.enableNodeReclamation(TrimInterval);
}
}
ExprEngine::~ExprEngine() {
BR.FlushReports();
}
//===----------------------------------------------------------------------===//
// Utility methods.
//===----------------------------------------------------------------------===//
ProgramStateRef ExprEngine::getInitialState(const LocationContext *InitLoc) {
ProgramStateRef state = StateMgr.getInitialState(InitLoc);
const Decl *D = InitLoc->getDecl();
// Preconditions.
// FIXME: It would be nice if we had a more general mechanism to add
// such preconditions. Some day.
do {
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();
const BuiltinType *BT = dyn_cast<BuiltinType>(T);
if (!BT || !BT->isInteger())
break;
const MemRegion *R = state->getRegion(PD, InitLoc);
if (!R)
break;
SVal V = state->getSVal(loc::MemRegionVal(R));
SVal Constraint_untested = evalBinOp(state, BO_GT, V,
svalBuilder.makeZeroVal(T),
svalBuilder.getConditionType());
Optional<DefinedOrUnknownSVal> Constraint =
Constraint_untested.getAs<DefinedOrUnknownSVal>();
if (!Constraint)
break;
if (ProgramStateRef newState = state->assume(*Constraint, true))
state = newState;
}
break;
}
while (0);
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 (Optional<Loc> LV = V.getAs<Loc>()) {
// Assume that the pointer value in 'self' is non-null.
state = state->assume(*LV, true);
assert(state && "'self' cannot be null");
}
}
if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(D)) {
if (!MD->isStatic()) {
// Precondition: 'this' is always non-null upon entry to the
// top-level function. This is our starting assumption for
// analyzing an "open" program.
const StackFrameContext *SFC = InitLoc->getCurrentStackFrame();
if (SFC->getParent() == nullptr) {
loc::MemRegionVal L = svalBuilder.getCXXThis(MD, SFC);
SVal V = state->getSVal(L);
if (Optional<Loc> LV = V.getAs<Loc>()) {
state = state->assume(*LV, true);
assert(state && "'this' cannot be null");
}
}
}
}
return state;
}
ProgramStateRef
ExprEngine::createTemporaryRegionIfNeeded(ProgramStateRef State,
const LocationContext *LC,
const Expr *Ex,
const Expr *Result) {
SVal V = State->getSVal(Ex, LC);
if (!Result) {
// If we don't have an explicit result expression, we're in "if needed"
// mode. Only create a region if the current value is a NonLoc.
if (!V.getAs<NonLoc>())
return State;
Result = Ex;
} else {
// We need to create a region no matter what. For sanity, make sure we don't
// try to stuff a Loc into a non-pointer temporary region.
assert(!V.getAs<Loc>() || Loc::isLocType(Result->getType()) ||
Result->getType()->isMemberPointerType());
}
ProgramStateManager &StateMgr = State->getStateManager();
MemRegionManager &MRMgr = StateMgr.getRegionManager();
StoreManager &StoreMgr = StateMgr.getStoreManager();
// MaterializeTemporaryExpr may appear out of place, after a few field and
// base-class accesses have been made to the object, even though semantically
// it is the whole object that gets materialized and lifetime-extended.
//
// For example:
//
// `-MaterializeTemporaryExpr
// `-MemberExpr
// `-CXXTemporaryObjectExpr
//
// instead of the more natural
//
// `-MemberExpr
// `-MaterializeTemporaryExpr
// `-CXXTemporaryObjectExpr
//
// Use the usual methods for obtaining the expression of the base object,
// and record the adjustments that we need to make to obtain the sub-object
// that the whole expression 'Ex' refers to. This trick is usual,
// in the sense that CodeGen takes a similar route.
SmallVector<const Expr *, 2> CommaLHSs;
SmallVector<SubobjectAdjustment, 2> Adjustments;
const Expr *Init = Ex->skipRValueSubobjectAdjustments(CommaLHSs, Adjustments);
const TypedValueRegion *TR = nullptr;
if (const MaterializeTemporaryExpr *MT =
dyn_cast<MaterializeTemporaryExpr>(Result)) {
StorageDuration SD = MT->getStorageDuration();
// If this object is bound to a reference with static storage duration, we
// put it in a different region to prevent "address leakage" warnings.
if (SD == SD_Static || SD == SD_Thread)
TR = MRMgr.getCXXStaticTempObjectRegion(Init);
}
if (!TR)
TR = MRMgr.getCXXTempObjectRegion(Init, LC);
SVal Reg = loc::MemRegionVal(TR);
// Make the necessary adjustments to obtain the sub-object.
for (auto I = Adjustments.rbegin(), E = Adjustments.rend(); I != E; ++I) {
const SubobjectAdjustment &Adj = *I;
switch (Adj.Kind) {
case SubobjectAdjustment::DerivedToBaseAdjustment:
Reg = StoreMgr.evalDerivedToBase(Reg, Adj.DerivedToBase.BasePath);
break;
case SubobjectAdjustment::FieldAdjustment:
Reg = StoreMgr.getLValueField(Adj.Field, Reg);
break;
case SubobjectAdjustment::MemberPointerAdjustment:
// FIXME: Unimplemented.
State->bindDefault(Reg, UnknownVal());
return State;
}
}
// Try to recover some path sensitivity in case we couldn't compute the value.
if (V.isUnknown())
V = getSValBuilder().conjureSymbolVal(Result, LC, TR->getValueType(),
currBldrCtx->blockCount());
// Bind the value of the expression to the sub-object region, and then bind
// the sub-object region to our expression.
State = State->bindLoc(Reg, V);
State = State->BindExpr(Result, LC, Reg);
return State;
}
//===----------------------------------------------------------------------===//
// Top-level transfer function logic (Dispatcher).
//===----------------------------------------------------------------------===//
/// evalAssume - Called by ConstraintManager. Used to call checker-specific
/// logic for handling assumptions on symbolic values.
ProgramStateRef ExprEngine::processAssume(ProgramStateRef state,
SVal cond, bool assumption) {
return getCheckerManager().runCheckersForEvalAssume(state, cond, assumption);
}
ProgramStateRef
ExprEngine::processRegionChanges(ProgramStateRef state,
const InvalidatedSymbols *invalidated,
ArrayRef<const MemRegion *> Explicits,
ArrayRef<const MemRegion *> Regions,
const CallEvent *Call) {
return getCheckerManager().runCheckersForRegionChanges(state, invalidated,
Explicits, Regions, Call);
}
void ExprEngine::printState(raw_ostream &Out, ProgramStateRef State,
const char *NL, const char *Sep) {
getCheckerManager().runCheckersForPrintState(Out, State, NL, Sep);
}
void ExprEngine::processEndWorklist(bool hasWorkRemaining) {
getCheckerManager().runCheckersForEndAnalysis(G, BR, *this);
}
void ExprEngine::processCFGElement(const CFGElement E, ExplodedNode *Pred,
unsigned StmtIdx, NodeBuilderContext *Ctx) {
PrettyStackTraceLocationContext CrashInfo(Pred->getLocationContext());
currStmtIdx = StmtIdx;
currBldrCtx = Ctx;
switch (E.getKind()) {
case CFGElement::Statement:
ProcessStmt(const_cast<Stmt*>(E.castAs<CFGStmt>().getStmt()), Pred);
return;
case CFGElement::Initializer:
ProcessInitializer(E.castAs<CFGInitializer>().getInitializer(), Pred);
return;
case CFGElement::NewAllocator:
ProcessNewAllocator(E.castAs<CFGNewAllocator>().getAllocatorExpr(),
Pred);
return;
case CFGElement::AutomaticObjectDtor:
case CFGElement::DeleteDtor:
case CFGElement::BaseDtor:
case CFGElement::MemberDtor:
case CFGElement::TemporaryDtor:
ProcessImplicitDtor(E.castAs<CFGImplicitDtor>(), Pred);
return;
}
}
static bool shouldRemoveDeadBindings(AnalysisManager &AMgr,
const CFGStmt S,
const ExplodedNode *Pred,
const LocationContext *LC) {
// Are we never purging state values?
if (AMgr.options.AnalysisPurgeOpt == PurgeNone)
return false;
// Is this the beginning of a basic block?
if (Pred->getLocation().getAs<BlockEntrance>())
return true;
// Is this on a non-expression?
if (!isa<Expr>(S.getStmt()))
return true;
// Run before processing a call.
if (CallEvent::isCallStmt(S.getStmt()))
return true;
// Is this an expression that is consumed by another expression? If so,
// postpone cleaning out the state.
ParentMap &PM = LC->getAnalysisDeclContext()->getParentMap();
return !PM.isConsumedExpr(cast<Expr>(S.getStmt()));
}
void ExprEngine::removeDead(ExplodedNode *Pred, ExplodedNodeSet &Out,
const Stmt *ReferenceStmt,
const LocationContext *LC,
const Stmt *DiagnosticStmt,
ProgramPoint::Kind K) {
assert((K == ProgramPoint::PreStmtPurgeDeadSymbolsKind ||
ReferenceStmt == nullptr || isa<ReturnStmt>(ReferenceStmt))
&& "PostStmt is not generally supported by the SymbolReaper yet");
assert(LC && "Must pass the current (or expiring) LocationContext");
if (!DiagnosticStmt) {
DiagnosticStmt = ReferenceStmt;
assert(DiagnosticStmt && "Required for clearing a LocationContext");
}
NumRemoveDeadBindings++;
ProgramStateRef CleanedState = Pred->getState();
// LC is the location context being destroyed, but SymbolReaper wants a
// location context that is still live. (If this is the top-level stack
// frame, this will be null.)
if (!ReferenceStmt) {
assert(K == ProgramPoint::PostStmtPurgeDeadSymbolsKind &&
"Use PostStmtPurgeDeadSymbolsKind for clearing a LocationContext");
LC = LC->getParent();
}
const StackFrameContext *SFC = LC ? LC->getCurrentStackFrame() : nullptr;
SymbolReaper SymReaper(SFC, ReferenceStmt, SymMgr, getStoreManager());
getCheckerManager().runCheckersForLiveSymbols(CleanedState, SymReaper);
// Create a state in which dead bindings are removed from the environment
// and the store. TODO: The function should just return new env and store,
// not a new state.
CleanedState = StateMgr.removeDeadBindings(CleanedState, SFC, SymReaper);
// Process any special transfer function for dead symbols.
// A tag to track convenience transitions, which can be removed at cleanup.
static SimpleProgramPointTag cleanupTag(TagProviderName, "Clean Node");
if (!SymReaper.hasDeadSymbols()) {
// Generate a CleanedNode that has the environment and store cleaned
// up. Since no symbols are dead, we can optimize and not clean out
// the constraint manager.
StmtNodeBuilder Bldr(Pred, Out, *currBldrCtx);
Bldr.generateNode(DiagnosticStmt, Pred, CleanedState, &cleanupTag, K);
} else {
// Call checkers with the non-cleaned state so that they could query the
// values of the soon to be dead symbols.
ExplodedNodeSet CheckedSet;
getCheckerManager().runCheckersForDeadSymbols(CheckedSet, Pred, SymReaper,
DiagnosticStmt, *this, K);
// For each node in CheckedSet, generate CleanedNodes that have the
// environment, the store, and the constraints cleaned up but have the
// user-supplied states as the predecessors.
StmtNodeBuilder Bldr(CheckedSet, Out, *currBldrCtx);
for (ExplodedNodeSet::const_iterator
I = CheckedSet.begin(), E = CheckedSet.end(); I != E; ++I) {
ProgramStateRef CheckerState = (*I)->getState();
// The constraint manager has not been cleaned up yet, so clean up now.
CheckerState = getConstraintManager().removeDeadBindings(CheckerState,
SymReaper);
assert(StateMgr.haveEqualEnvironments(CheckerState, Pred->getState()) &&
"Checkers are not allowed to modify the Environment as a part of "
"checkDeadSymbols processing.");
assert(StateMgr.haveEqualStores(CheckerState, Pred->getState()) &&
"Checkers are not allowed to modify the Store as a part of "
"checkDeadSymbols processing.");
// Create a state based on CleanedState with CheckerState GDM and
// generate a transition to that state.
ProgramStateRef CleanedCheckerSt =
StateMgr.getPersistentStateWithGDM(CleanedState, CheckerState);
Bldr.generateNode(DiagnosticStmt, *I, CleanedCheckerSt, &cleanupTag, K);
}
}
}
void ExprEngine::ProcessStmt(const CFGStmt S,
ExplodedNode *Pred) {
// Reclaim any unnecessary nodes in the ExplodedGraph.
G.reclaimRecentlyAllocatedNodes();
const Stmt *currStmt = S.getStmt();
PrettyStackTraceLoc CrashInfo(getContext().getSourceManager(),
currStmt->getLocStart(),
"Error evaluating statement");
// Remove dead bindings and symbols.
ExplodedNodeSet CleanedStates;
if (shouldRemoveDeadBindings(AMgr, S, Pred, Pred->getLocationContext())){
removeDead(Pred, CleanedStates, currStmt, Pred->getLocationContext());
} else
CleanedStates.Add(Pred);
// Visit the statement.
ExplodedNodeSet Dst;
for (ExplodedNodeSet::iterator I = CleanedStates.begin(),
E = CleanedStates.end(); I != E; ++I) {
ExplodedNodeSet DstI;
// Visit the statement.
Visit(currStmt, *I, DstI);
Dst.insert(DstI);
}
// Enqueue the new nodes onto the work list.
Engine.enqueue(Dst, currBldrCtx->getBlock(), currStmtIdx);
}
void ExprEngine::ProcessInitializer(const CFGInitializer Init,
ExplodedNode *Pred) {
const CXXCtorInitializer *BMI = Init.getInitializer();
PrettyStackTraceLoc CrashInfo(getContext().getSourceManager(),
BMI->getSourceLocation(),
"Error evaluating initializer");
// We don't clean up dead bindings here.
const StackFrameContext *stackFrame =
cast<StackFrameContext>(Pred->getLocationContext());
const CXXConstructorDecl *decl =
cast<CXXConstructorDecl>(stackFrame->getDecl());
ProgramStateRef State = Pred->getState();
SVal thisVal = State->getSVal(svalBuilder.getCXXThis(decl, stackFrame));
ExplodedNodeSet Tmp(Pred);
SVal FieldLoc;
// Evaluate the initializer, if necessary
if (BMI->isAnyMemberInitializer()) {
// Constructors build the object directly in the field,
// but non-objects must be copied in from the initializer.
if (auto *CtorExpr = findDirectConstructorForCurrentCFGElement()) {
assert(BMI->getInit()->IgnoreImplicit() == CtorExpr);
(void)CtorExpr;
// The field was directly constructed, so there is no need to bind.
} else {
const Expr *Init = BMI->getInit()->IgnoreImplicit();
const ValueDecl *Field;
if (BMI->isIndirectMemberInitializer()) {
Field = BMI->getIndirectMember();
FieldLoc = State->getLValue(BMI->getIndirectMember(), thisVal);
} else {
Field = BMI->getMember();
FieldLoc = State->getLValue(BMI->getMember(), thisVal);
}
SVal InitVal;
if (BMI->getNumArrayIndices() > 0) {
// Handle arrays of trivial type. We can represent this with a
// primitive load/copy from the base array region.
const ArraySubscriptExpr *ASE;
while ((ASE = dyn_cast<ArraySubscriptExpr>(Init)))
Init = ASE->getBase()->IgnoreImplicit();
SVal LValue = State->getSVal(Init, stackFrame);
if (!Field->getType()->isReferenceType())
if (Optional<Loc> LValueLoc = LValue.getAs<Loc>())
InitVal = State->getSVal(*LValueLoc);
// If we fail to get the value for some reason, use a symbolic value.
if (InitVal.isUnknownOrUndef()) {
SValBuilder &SVB = getSValBuilder();
InitVal = SVB.conjureSymbolVal(BMI->getInit(), stackFrame,
Field->getType(),
currBldrCtx->blockCount());
}
} else {
InitVal = State->getSVal(BMI->getInit(), stackFrame);
}
assert(Tmp.size() == 1 && "have not generated any new nodes yet");
assert(*Tmp.begin() == Pred && "have not generated any new nodes yet");
Tmp.clear();
PostInitializer PP(BMI, FieldLoc.getAsRegion(), stackFrame);
evalBind(Tmp, Init, Pred, FieldLoc, InitVal, /*isInit=*/true, &PP);
}
} else {
assert(BMI->isBaseInitializer() || BMI->isDelegatingInitializer());
// We already did all the work when visiting the CXXConstructExpr.
}
// Construct PostInitializer nodes whether the state changed or not,
// so that the diagnostics don't get confused.
PostInitializer PP(BMI, FieldLoc.getAsRegion(), stackFrame);
ExplodedNodeSet Dst;
NodeBuilder Bldr(Tmp, Dst, *currBldrCtx);
for (ExplodedNodeSet::iterator I = Tmp.begin(), E = Tmp.end(); I != E; ++I) {
ExplodedNode *N = *I;
Bldr.generateNode(PP, N->getState(), N);
}
// Enqueue the new nodes onto the work list.
Engine.enqueue(Dst, currBldrCtx->getBlock(), currStmtIdx);
}
void ExprEngine::ProcessImplicitDtor(const CFGImplicitDtor D,
ExplodedNode *Pred) {
ExplodedNodeSet Dst;
switch (D.getKind()) {
case CFGElement::AutomaticObjectDtor:
ProcessAutomaticObjDtor(D.castAs<CFGAutomaticObjDtor>(), Pred, Dst);
break;
case CFGElement::BaseDtor:
ProcessBaseDtor(D.castAs<CFGBaseDtor>(), Pred, Dst);
break;
case CFGElement::MemberDtor:
ProcessMemberDtor(D.castAs<CFGMemberDtor>(), Pred, Dst);
break;
case CFGElement::TemporaryDtor:
ProcessTemporaryDtor(D.castAs<CFGTemporaryDtor>(), Pred, Dst);
break;
case CFGElement::DeleteDtor:
ProcessDeleteDtor(D.castAs<CFGDeleteDtor>(), Pred, Dst);
break;
default:
llvm_unreachable("Unexpected dtor kind.");
}
// Enqueue the new nodes onto the work list.
Engine.enqueue(Dst, currBldrCtx->getBlock(), currStmtIdx);
}
void ExprEngine::ProcessNewAllocator(const CXXNewExpr *NE,
ExplodedNode *Pred) {
ExplodedNodeSet Dst;
AnalysisManager &AMgr = getAnalysisManager();
AnalyzerOptions &Opts = AMgr.options;
// TODO: We're not evaluating allocators for all cases just yet as
// we're not handling the return value correctly, which causes false
// positives when the alpha.cplusplus.NewDeleteLeaks check is on.
if (Opts.mayInlineCXXAllocator())
VisitCXXNewAllocatorCall(NE, Pred, Dst);
else {
NodeBuilder Bldr(Pred, Dst, *currBldrCtx);
const LocationContext *LCtx = Pred->getLocationContext();
PostImplicitCall PP(NE->getOperatorNew(), NE->getLocStart(), LCtx);
Bldr.generateNode(PP, Pred->getState(), Pred);
}
Engine.enqueue(Dst, currBldrCtx->getBlock(), currStmtIdx);
}
void ExprEngine::ProcessAutomaticObjDtor(const CFGAutomaticObjDtor Dtor,
ExplodedNode *Pred,
ExplodedNodeSet &Dst) {
const VarDecl *varDecl = Dtor.getVarDecl();
QualType varType = varDecl->getType();
ProgramStateRef state = Pred->getState();
SVal dest = state->getLValue(varDecl, Pred->getLocationContext());
const MemRegion *Region = dest.castAs<loc::MemRegionVal>().getRegion();
if (varType->isReferenceType()) {
const MemRegion *ValueRegion = state->getSVal(Region).getAsRegion();
if (!ValueRegion) {
// FIXME: This should not happen. The language guarantees a presence
// of a valid initializer here, so the reference shall not be undefined.
// It seems that we're calling destructors over variables that
// were not initialized yet.
return;
}
Region = ValueRegion->getBaseRegion();
varType = cast<TypedValueRegion>(Region)->getValueType();
}
VisitCXXDestructor(varType, Region, Dtor.getTriggerStmt(), /*IsBase=*/ false,
Pred, Dst);
}
void ExprEngine::ProcessDeleteDtor(const CFGDeleteDtor Dtor,
ExplodedNode *Pred,
ExplodedNodeSet &Dst) {
ProgramStateRef State = Pred->getState();
const LocationContext *LCtx = Pred->getLocationContext();
const CXXDeleteExpr *DE = Dtor.getDeleteExpr();
const Stmt *Arg = DE->getArgument();
SVal ArgVal = State->getSVal(Arg, LCtx);
// If the argument to delete is known to be a null value,
// don't run destructor.
if (State->isNull(ArgVal).isConstrainedTrue()) {
QualType DTy = DE->getDestroyedType();
QualType BTy = getContext().getBaseElementType(DTy);
const CXXRecordDecl *RD = BTy->getAsCXXRecordDecl();
const CXXDestructorDecl *Dtor = RD->getDestructor();
PostImplicitCall PP(Dtor, DE->getLocStart(), LCtx);
NodeBuilder Bldr(Pred, Dst, *currBldrCtx);
Bldr.generateNode(PP, Pred->getState(), Pred);
return;
}
VisitCXXDestructor(DE->getDestroyedType(),
ArgVal.getAsRegion(),
DE, /*IsBase=*/ false,
Pred, Dst);
}
void ExprEngine::ProcessBaseDtor(const CFGBaseDtor D,
ExplodedNode *Pred, ExplodedNodeSet &Dst) {
const LocationContext *LCtx = Pred->getLocationContext();
const CXXDestructorDecl *CurDtor = cast<CXXDestructorDecl>(LCtx->getDecl());
Loc ThisPtr = getSValBuilder().getCXXThis(CurDtor,
LCtx->getCurrentStackFrame());
SVal ThisVal = Pred->getState()->getSVal(ThisPtr);
// Create the base object region.
const CXXBaseSpecifier *Base = D.getBaseSpecifier();
QualType BaseTy = Base->getType();
SVal BaseVal = getStoreManager().evalDerivedToBase(ThisVal, BaseTy,
Base->isVirtual());
VisitCXXDestructor(BaseTy, BaseVal.castAs<loc::MemRegionVal>().getRegion(),
CurDtor->getBody(), /*IsBase=*/ true, Pred, Dst);
}
void ExprEngine::ProcessMemberDtor(const CFGMemberDtor D,
ExplodedNode *Pred, ExplodedNodeSet &Dst) {
const FieldDecl *Member = D.getFieldDecl();
ProgramStateRef State = Pred->getState();
const LocationContext *LCtx = Pred->getLocationContext();
const CXXDestructorDecl *CurDtor = cast<CXXDestructorDecl>(LCtx->getDecl());
Loc ThisVal = getSValBuilder().getCXXThis(CurDtor,
LCtx->getCurrentStackFrame());
SVal FieldVal =
State->getLValue(Member, State->getSVal(ThisVal).castAs<Loc>());
VisitCXXDestructor(Member->getType(),
FieldVal.castAs<loc::MemRegionVal>().getRegion(),
CurDtor->getBody(), /*IsBase=*/false, Pred, Dst);
}
void ExprEngine::ProcessTemporaryDtor(const CFGTemporaryDtor D,
ExplodedNode *Pred,
ExplodedNodeSet &Dst) {
ExplodedNodeSet CleanDtorState;
StmtNodeBuilder StmtBldr(Pred, CleanDtorState, *currBldrCtx);
ProgramStateRef State = Pred->getState();
if (State->contains<InitializedTemporariesSet>(
std::make_pair(D.getBindTemporaryExpr(), Pred->getStackFrame()))) {
// FIXME: Currently we insert temporary destructors for default parameters,
// but we don't insert the constructors.
State = State->remove<InitializedTemporariesSet>(
std::make_pair(D.getBindTemporaryExpr(), Pred->getStackFrame()));
}
StmtBldr.generateNode(D.getBindTemporaryExpr(), Pred, State);
QualType varType = D.getBindTemporaryExpr()->getSubExpr()->getType();
// FIXME: Currently CleanDtorState can be empty here due to temporaries being
// bound to default parameters.
assert(CleanDtorState.size() <= 1);
ExplodedNode *CleanPred =
CleanDtorState.empty() ? Pred : *CleanDtorState.begin();
// FIXME: Inlining of temporary destructors is not supported yet anyway, so
// we just put a NULL region for now. This will need to be changed later.
VisitCXXDestructor(varType, nullptr, D.getBindTemporaryExpr(),
/*IsBase=*/false, CleanPred, Dst);
}
void ExprEngine::processCleanupTemporaryBranch(const CXXBindTemporaryExpr *BTE,
NodeBuilderContext &BldCtx,
ExplodedNode *Pred,
ExplodedNodeSet &Dst,
const CFGBlock *DstT,
const CFGBlock *DstF) {
BranchNodeBuilder TempDtorBuilder(Pred, Dst, BldCtx, DstT, DstF);
if (Pred->getState()->contains<InitializedTemporariesSet>(
std::make_pair(BTE, Pred->getStackFrame()))) {
TempDtorBuilder.markInfeasible(false);
TempDtorBuilder.generateNode(Pred->getState(), true, Pred);
} else {
TempDtorBuilder.markInfeasible(true);
TempDtorBuilder.generateNode(Pred->getState(), false, Pred);
}
}
void ExprEngine::VisitCXXBindTemporaryExpr(const CXXBindTemporaryExpr *BTE,
ExplodedNodeSet &PreVisit,
ExplodedNodeSet &Dst) {
if (!getAnalysisManager().options.includeTemporaryDtorsInCFG()) {
// In case we don't have temporary destructors in the CFG, do not mark
// the initialization - we would otherwise never clean it up.
Dst = PreVisit;
return;
}
StmtNodeBuilder StmtBldr(PreVisit, Dst, *currBldrCtx);
for (ExplodedNode *Node : PreVisit) {
ProgramStateRef State = Node->getState();
if (!State->contains<InitializedTemporariesSet>(
std::make_pair(BTE, Node->getStackFrame()))) {
// FIXME: Currently the state might already contain the marker due to
// incorrect handling of temporaries bound to default parameters; for
// those, we currently skip the CXXBindTemporaryExpr but rely on adding
// temporary destructor nodes.
State = State->add<InitializedTemporariesSet>(
std::make_pair(BTE, Node->getStackFrame()));
}
StmtBldr.generateNode(BTE, Node, State);
}
}
void ExprEngine::Visit(const Stmt *S, ExplodedNode *Pred,
ExplodedNodeSet &DstTop) {
PrettyStackTraceLoc CrashInfo(getContext().getSourceManager(),
S->getLocStart(),
"Error evaluating statement");
ExplodedNodeSet Dst;
StmtNodeBuilder Bldr(Pred, DstTop, *currBldrCtx);
assert(!isa<Expr>(S) || S == cast<Expr>(S)->IgnoreParens());
switch (S->getStmtClass()) {
// C++ and ARC stuff we don't support yet.
case Expr::ObjCIndirectCopyRestoreExprClass:
case Stmt::CXXDependentScopeMemberExprClass:
case Stmt::CXXInheritedCtorInitExprClass:
case Stmt::CXXTryStmtClass:
case Stmt::CXXTypeidExprClass:
case Stmt::CXXUuidofExprClass:
case Stmt::CXXFoldExprClass:
case Stmt::MSPropertyRefExprClass:
case Stmt::MSPropertySubscriptExprClass:
case Stmt::CXXUnresolvedConstructExprClass:
case Stmt::DependentScopeDeclRefExprClass:
case Stmt::ArrayTypeTraitExprClass:
case Stmt::ExpressionTraitExprClass:
case Stmt::UnresolvedLookupExprClass:
case Stmt::UnresolvedMemberExprClass:
case Stmt::TypoExprClass:
case Stmt::CXXNoexceptExprClass:
case Stmt::PackExpansionExprClass:
case Stmt::SubstNonTypeTemplateParmPackExprClass:
case Stmt::FunctionParmPackExprClass:
case Stmt::CoroutineBodyStmtClass:
case Stmt::CoawaitExprClass:
case Stmt::CoreturnStmtClass:
case Stmt::CoyieldExprClass:
case Stmt::SEHTryStmtClass:
case Stmt::SEHExceptStmtClass:
case Stmt::SEHLeaveStmtClass:
case Stmt::SEHFinallyStmtClass: {
const ExplodedNode *node = Bldr.generateSink(S, Pred, Pred->getState());
Engine.addAbortedBlock(node, currBldrCtx->getBlock());
break;
}
case Stmt::ParenExprClass:
llvm_unreachable("ParenExprs already handled.");
case Stmt::GenericSelectionExprClass:
llvm_unreachable("GenericSelectionExprs already handled.");
// Cases that should never be evaluated simply because they shouldn't
// appear in the CFG.
case Stmt::BreakStmtClass:
case Stmt::CaseStmtClass:
case Stmt::CompoundStmtClass:
case Stmt::ContinueStmtClass:
case Stmt::CXXForRangeStmtClass:
case Stmt::DefaultStmtClass:
case Stmt::DoStmtClass:
case Stmt::ForStmtClass:
case Stmt::GotoStmtClass:
case Stmt::IfStmtClass:
case Stmt::IndirectGotoStmtClass:
case Stmt::LabelStmtClass:
case Stmt::NoStmtClass:
case Stmt::NullStmtClass:
case Stmt::SwitchStmtClass:
case Stmt::WhileStmtClass:
case Expr::MSDependentExistsStmtClass:
case Stmt::CapturedStmtClass:
case Stmt::OMPParallelDirectiveClass:
case Stmt::OMPSimdDirectiveClass:
case Stmt::OMPForDirectiveClass:
case Stmt::OMPForSimdDirectiveClass:
case Stmt::OMPSectionsDirectiveClass:
case Stmt::OMPSectionDirectiveClass:
case Stmt::OMPSingleDirectiveClass:
case Stmt::OMPMasterDirectiveClass:
case Stmt::OMPCriticalDirectiveClass:
case Stmt::OMPParallelForDirectiveClass:
case Stmt::OMPParallelForSimdDirectiveClass:
case Stmt::OMPParallelSectionsDirectiveClass:
case Stmt::OMPTaskDirectiveClass:
case Stmt::OMPTaskyieldDirectiveClass:
case Stmt::OMPBarrierDirectiveClass:
case Stmt::OMPTaskwaitDirectiveClass:
case Stmt::OMPTaskgroupDirectiveClass:
case Stmt::OMPFlushDirectiveClass:
case Stmt::OMPOrderedDirectiveClass:
case Stmt::OMPAtomicDirectiveClass:
case Stmt::OMPTargetDirectiveClass:
case Stmt::OMPTargetDataDirectiveClass:
case Stmt::OMPTargetEnterDataDirectiveClass:
case Stmt::OMPTargetExitDataDirectiveClass:
case Stmt::OMPTargetParallelDirectiveClass:
case Stmt::OMPTargetParallelForDirectiveClass:
case Stmt::OMPTargetUpdateDirectiveClass:
case Stmt::OMPTeamsDirectiveClass:
case Stmt::OMPCancellationPointDirectiveClass:
case Stmt::OMPCancelDirectiveClass:
case Stmt::OMPTaskLoopDirectiveClass:
case Stmt::OMPTaskLoopSimdDirectiveClass:
case Stmt::OMPDistributeDirectiveClass:
case Stmt::OMPDistributeParallelForDirectiveClass:
case Stmt::OMPDistributeParallelForSimdDirectiveClass:
case Stmt::OMPDistributeSimdDirectiveClass:
case Stmt::OMPTargetParallelForSimdDirectiveClass:
case Stmt::OMPTargetSimdDirectiveClass:
case Stmt::OMPTeamsDistributeDirectiveClass:
llvm_unreachable("Stmt should not be in analyzer evaluation loop");
case Stmt::ObjCSubscriptRefExprClass:
case Stmt::ObjCPropertyRefExprClass:
llvm_unreachable("These are handled by PseudoObjectExpr");
case Stmt::GNUNullExprClass: {
// GNU __null is a pointer-width integer, not an actual pointer.
ProgramStateRef state = Pred->getState();
state = state->BindExpr(S, Pred->getLocationContext(),
svalBuilder.makeIntValWithPtrWidth(0, false));
Bldr.generateNode(S, Pred, state);
break;
}
case Stmt::ObjCAtSynchronizedStmtClass:
Bldr.takeNodes(Pred);
VisitObjCAtSynchronizedStmt(cast<ObjCAtSynchronizedStmt>(S), Pred, Dst);
Bldr.addNodes(Dst);
break;
case Stmt::ExprWithCleanupsClass:
// Handled due to fully linearised CFG.
break;
case Stmt::CXXBindTemporaryExprClass: {
Bldr.takeNodes(Pred);
ExplodedNodeSet PreVisit;
getCheckerManager().runCheckersForPreStmt(PreVisit, Pred, S, *this);
ExplodedNodeSet Next;
VisitCXXBindTemporaryExpr(cast<CXXBindTemporaryExpr>(S), PreVisit, Next);
getCheckerManager().runCheckersForPostStmt(Dst, Next, S, *this);
Bldr.addNodes(Dst);
break;
}
// Cases not handled yet; but will handle some day.
case Stmt::DesignatedInitExprClass:
case Stmt::DesignatedInitUpdateExprClass:
case Stmt::ExtVectorElementExprClass:
case Stmt::ImaginaryLiteralClass:
case Stmt::ObjCAtCatchStmtClass:
case Stmt::ObjCAtFinallyStmtClass:
case Stmt::ObjCAtTryStmtClass:
case Stmt::ObjCAutoreleasePoolStmtClass:
case Stmt::ObjCEncodeExprClass:
case Stmt::ObjCIsaExprClass:
case Stmt::ObjCProtocolExprClass:
case Stmt::ObjCSelectorExprClass:
case Stmt::ParenListExprClass:
case Stmt::ShuffleVectorExprClass:
case Stmt::ConvertVectorExprClass:
case Stmt::VAArgExprClass:
case Stmt::CUDAKernelCallExprClass:
case Stmt::OpaqueValueExprClass:
case Stmt::AsTypeExprClass:
// Fall through.
// Cases we intentionally don't evaluate, since they don't need
// to be explicitly evaluated.
case Stmt::PredefinedExprClass:
case Stmt::AddrLabelExprClass:
case Stmt::AttributedStmtClass:
case Stmt::IntegerLiteralClass:
case Stmt::CharacterLiteralClass:
case Stmt::ImplicitValueInitExprClass:
case Stmt::CXXScalarValueInitExprClass:
case Stmt::CXXBoolLiteralExprClass:
case Stmt::ObjCBoolLiteralExprClass:
case Stmt::ObjCAvailabilityCheckExprClass:
case Stmt::FloatingLiteralClass:
case Stmt::NoInitExprClass:
case Stmt::SizeOfPackExprClass:
case Stmt::StringLiteralClass:
case Stmt::ObjCStringLiteralClass:
case Stmt::CXXPseudoDestructorExprClass:
case Stmt::SubstNonTypeTemplateParmExprClass:
case Stmt::CXXNullPtrLiteralExprClass:
case Stmt::OMPArraySectionExprClass:
case Stmt::TypeTraitExprClass: {
Bldr.takeNodes(Pred);
ExplodedNodeSet preVisit;
getCheckerManager().runCheckersForPreStmt(preVisit, Pred, S, *this);
getCheckerManager().runCheckersForPostStmt(Dst, preVisit, S, *this);
Bldr.addNodes(Dst);
break;
}
case Stmt::CXXDefaultArgExprClass:
case Stmt::CXXDefaultInitExprClass: {
Bldr.takeNodes(Pred);
ExplodedNodeSet PreVisit;
getCheckerManager().runCheckersForPreStmt(PreVisit, Pred, S, *this);
ExplodedNodeSet Tmp;
StmtNodeBuilder Bldr2(PreVisit, Tmp, *currBldrCtx);
const Expr *ArgE;
if (const CXXDefaultArgExpr *DefE = dyn_cast<CXXDefaultArgExpr>(S))
ArgE = DefE->getExpr();
else if (const CXXDefaultInitExpr *DefE = dyn_cast<CXXDefaultInitExpr>(S))
ArgE = DefE->getExpr();
else
llvm_unreachable("unknown constant wrapper kind");
bool IsTemporary = false;
if (const MaterializeTemporaryExpr *MTE =
dyn_cast<MaterializeTemporaryExpr>(ArgE)) {
ArgE = MTE->GetTemporaryExpr();
IsTemporary = true;
}
Optional<SVal> ConstantVal = svalBuilder.getConstantVal(ArgE);
if (!ConstantVal)
ConstantVal = UnknownVal();
const LocationContext *LCtx = Pred->getLocationContext();
for (ExplodedNodeSet::iterator I = PreVisit.begin(), E = PreVisit.end();
I != E; ++I) {
ProgramStateRef State = (*I)->getState();
State = State->BindExpr(S, LCtx, *ConstantVal);
if (IsTemporary)
State = createTemporaryRegionIfNeeded(State, LCtx,
cast<Expr>(S),
cast<Expr>(S));
Bldr2.generateNode(S, *I, State);
}
getCheckerManager().runCheckersForPostStmt(Dst, Tmp, S, *this);
Bldr.addNodes(Dst);
break;
}
// Cases we evaluate as opaque expressions, conjuring a symbol.
case Stmt::CXXStdInitializerListExprClass:
case Expr::ObjCArrayLiteralClass:
case Expr::ObjCDictionaryLiteralClass:
case Expr::ObjCBoxedExprClass: {
Bldr.takeNodes(Pred);
ExplodedNodeSet preVisit;
getCheckerManager().runCheckersForPreStmt(preVisit, Pred, S, *this);
ExplodedNodeSet Tmp;
StmtNodeBuilder Bldr2(preVisit, Tmp, *currBldrCtx);
const Expr *Ex = cast<Expr>(S);
QualType resultType = Ex->getType();
for (ExplodedNodeSet::iterator it = preVisit.begin(), et = preVisit.end();
it != et; ++it) {
ExplodedNode *N = *it;
const LocationContext *LCtx = N->getLocationContext();
SVal result = svalBuilder.conjureSymbolVal(nullptr, Ex, LCtx,
resultType,
currBldrCtx->blockCount());
ProgramStateRef state = N->getState()->BindExpr(Ex, LCtx, result);
Bldr2.generateNode(S, N, state);
}
getCheckerManager().runCheckersForPostStmt(Dst, Tmp, S, *this);
Bldr.addNodes(Dst);
break;
}
case Stmt::ArraySubscriptExprClass:
Bldr.takeNodes(Pred);
VisitLvalArraySubscriptExpr(cast<ArraySubscriptExpr>(S), Pred, Dst);
Bldr.addNodes(Dst);
break;
case Stmt::GCCAsmStmtClass:
Bldr.takeNodes(Pred);
VisitGCCAsmStmt(cast<GCCAsmStmt>(S), Pred, Dst);
Bldr.addNodes(Dst);
break;
case Stmt::MSAsmStmtClass:
Bldr.takeNodes(Pred);
VisitMSAsmStmt(cast<MSAsmStmt>(S), Pred, Dst);
Bldr.addNodes(Dst);
break;
case Stmt::BlockExprClass:
Bldr.takeNodes(Pred);
VisitBlockExpr(cast<BlockExpr>(S), Pred, Dst);
Bldr.addNodes(Dst);
break;
case Stmt::LambdaExprClass:
if (AMgr.options.shouldInlineLambdas()) {
Bldr.takeNodes(Pred);
VisitLambdaExpr(cast<LambdaExpr>(S), Pred, Dst);
Bldr.addNodes(Dst);
} else {
const ExplodedNode *node = Bldr.generateSink(S, Pred, Pred->getState());
Engine.addAbortedBlock(node, currBldrCtx->getBlock());
}
break;
case Stmt::BinaryOperatorClass: {
const BinaryOperator* B = cast<BinaryOperator>(S);
if (B->isLogicalOp()) {
Bldr.takeNodes(Pred);
VisitLogicalExpr(B, Pred, Dst);
Bldr.addNodes(Dst);
break;
}
else if (B->getOpcode() == BO_Comma) {
ProgramStateRef state = Pred->getState();
Bldr.generateNode(B, Pred,
state->BindExpr(B, Pred->getLocationContext(),
state->getSVal(B->getRHS(),
Pred->getLocationContext())));
break;
}
Bldr.takeNodes(Pred);
if (AMgr.options.eagerlyAssumeBinOpBifurcation &&
(B->isRelationalOp() || B->isEqualityOp())) {
ExplodedNodeSet Tmp;
VisitBinaryOperator(cast<BinaryOperator>(S), Pred, Tmp);
evalEagerlyAssumeBinOpBifurcation(Dst, Tmp, cast<Expr>(S));
}
else
VisitBinaryOperator(cast<BinaryOperator>(S), Pred, Dst);
Bldr.addNodes(Dst);
break;
}
case Stmt::CXXOperatorCallExprClass: {
const CXXOperatorCallExpr *OCE = cast<CXXOperatorCallExpr>(S);
// For instance method operators, make sure the 'this' argument has a
// valid region.
const Decl *Callee = OCE->getCalleeDecl();
if (const CXXMethodDecl *MD = dyn_cast_or_null<CXXMethodDecl>(Callee)) {
if (MD->isInstance()) {
ProgramStateRef State = Pred->getState();
const LocationContext *LCtx = Pred->getLocationContext();
ProgramStateRef NewState =
createTemporaryRegionIfNeeded(State, LCtx, OCE->getArg(0));
if (NewState != State) {
Pred = Bldr.generateNode(OCE, Pred, NewState, /*Tag=*/nullptr,
ProgramPoint::PreStmtKind);
// Did we cache out?
if (!Pred)
break;
}
}
}
// FALLTHROUGH
}
case Stmt::CallExprClass:
case Stmt::CXXMemberCallExprClass:
case Stmt::UserDefinedLiteralClass: {
Bldr.takeNodes(Pred);
VisitCallExpr(cast<CallExpr>(S), Pred, Dst);
Bldr.addNodes(Dst);
break;
}
case Stmt::CXXCatchStmtClass: {
Bldr.takeNodes(Pred);
VisitCXXCatchStmt(cast<CXXCatchStmt>(S), Pred, Dst);
Bldr.addNodes(Dst);
break;
}
case Stmt::CXXTemporaryObjectExprClass:
case Stmt::CXXConstructExprClass: {
Bldr.takeNodes(Pred);
VisitCXXConstructExpr(cast<CXXConstructExpr>(S), Pred, Dst);
Bldr.addNodes(Dst);
break;
}
case Stmt::CXXNewExprClass: {
Bldr.takeNodes(Pred);
ExplodedNodeSet PostVisit;
VisitCXXNewExpr(cast<CXXNewExpr>(S), Pred, PostVisit);
getCheckerManager().runCheckersForPostStmt(Dst, PostVisit, S, *this);
Bldr.addNodes(Dst);
break;
}
case Stmt::CXXDeleteExprClass: {
Bldr.takeNodes(Pred);
ExplodedNodeSet PreVisit;
const CXXDeleteExpr *CDE = cast<CXXDeleteExpr>(S);
getCheckerManager().runCheckersForPreStmt(PreVisit, Pred, S, *this);
for (ExplodedNodeSet::iterator i = PreVisit.begin(),
e = PreVisit.end(); i != e ; ++i)
VisitCXXDeleteExpr(CDE, *i, Dst);
Bldr.addNodes(Dst);
break;
}
// FIXME: ChooseExpr is really a constant. We need to fix
// the CFG do not model them as explicit control-flow.
case Stmt::ChooseExprClass: { // __builtin_choose_expr
Bldr.takeNodes(Pred);
const ChooseExpr *C = cast<ChooseExpr>(S);
VisitGuardedExpr(C, C->getLHS(), C->getRHS(), Pred, Dst);
Bldr.addNodes(Dst);
break;
}
case Stmt::CompoundAssignOperatorClass:
Bldr.takeNodes(Pred);
VisitBinaryOperator(cast<BinaryOperator>(S), Pred, Dst);
Bldr.addNodes(Dst);
break;
case Stmt::CompoundLiteralExprClass:
Bldr.takeNodes(Pred);
VisitCompoundLiteralExpr(cast<CompoundLiteralExpr>(S), Pred, Dst);
Bldr.addNodes(Dst);
break;
case Stmt::BinaryConditionalOperatorClass:
case Stmt::ConditionalOperatorClass: { // '?' operator
Bldr.takeNodes(Pred);
const AbstractConditionalOperator *C
= cast<AbstractConditionalOperator>(S);
VisitGuardedExpr(C, C->getTrueExpr(), C->getFalseExpr(), Pred, Dst);
Bldr.addNodes(Dst);
break;
}
case Stmt::CXXThisExprClass:
Bldr.takeNodes(Pred);
VisitCXXThisExpr(cast<CXXThisExpr>(S), Pred, Dst);
Bldr.addNodes(Dst);
break;
case Stmt::DeclRefExprClass: {
Bldr.takeNodes(Pred);
const DeclRefExpr *DE = cast<DeclRefExpr>(S);
VisitCommonDeclRefExpr(DE, DE->getDecl(), Pred, Dst);
Bldr.addNodes(Dst);
break;
}
case Stmt::DeclStmtClass:
Bldr.takeNodes(Pred);
VisitDeclStmt(cast<DeclStmt>(S), Pred, Dst);
Bldr.addNodes(Dst);
break;
case Stmt::ImplicitCastExprClass:
case Stmt::CStyleCastExprClass:
case Stmt::CXXStaticCastExprClass:
case Stmt::CXXDynamicCastExprClass:
case Stmt::CXXReinterpretCastExprClass:
case Stmt::CXXConstCastExprClass:
case Stmt::CXXFunctionalCastExprClass:
case Stmt::ObjCBridgedCastExprClass: {
Bldr.takeNodes(Pred);
const CastExpr *C = cast<CastExpr>(S);
ExplodedNodeSet dstExpr;
VisitCast(C, C->getSubExpr(), Pred, dstExpr);
// Handle the postvisit checks.
getCheckerManager().runCheckersForPostStmt(Dst, dstExpr, C, *this);
Bldr.addNodes(Dst);
break;
}
case Expr::MaterializeTemporaryExprClass: {
Bldr.takeNodes(Pred);
const MaterializeTemporaryExpr *MTE = cast<MaterializeTemporaryExpr>(S);
CreateCXXTemporaryObject(MTE, Pred, Dst);
Bldr.addNodes(Dst);
break;
}
case Stmt::InitListExprClass:
Bldr.takeNodes(Pred);
VisitInitListExpr(cast<InitListExpr>(S), Pred, Dst);
Bldr.addNodes(Dst);
break;
case Stmt::MemberExprClass:
Bldr.takeNodes(Pred);
VisitMemberExpr(cast<MemberExpr>(S), Pred, Dst);
Bldr.addNodes(Dst);
break;
case Stmt::AtomicExprClass:
Bldr.takeNodes(Pred);
VisitAtomicExpr(cast<AtomicExpr>(S), Pred, Dst);
Bldr.addNodes(Dst);
break;
case Stmt::ObjCIvarRefExprClass:
Bldr.takeNodes(Pred);
VisitLvalObjCIvarRefExpr(cast<ObjCIvarRefExpr>(S), Pred, Dst);
Bldr.addNodes(Dst);
break;
case Stmt::ObjCForCollectionStmtClass:
Bldr.takeNodes(Pred);
VisitObjCForCollectionStmt(cast<ObjCForCollectionStmt>(S), Pred, Dst);
Bldr.addNodes(Dst);
break;
case Stmt::ObjCMessageExprClass:
Bldr.takeNodes(Pred);
VisitObjCMessage(cast<ObjCMessageExpr>(S), Pred, Dst);
Bldr.addNodes(Dst);
break;
case Stmt::ObjCAtThrowStmtClass:
case Stmt::CXXThrowExprClass:
// FIXME: This is not complete. We basically treat @throw as
// an abort.
Bldr.generateSink(S, Pred, Pred->getState());
break;
case Stmt::ReturnStmtClass:
Bldr.takeNodes(Pred);
VisitReturnStmt(cast<ReturnStmt>(S), Pred, Dst);
Bldr.addNodes(Dst);
break;
case Stmt::OffsetOfExprClass:
Bldr.takeNodes(Pred);
VisitOffsetOfExpr(cast<OffsetOfExpr>(S), Pred, Dst);
Bldr.addNodes(Dst);
break;
case Stmt::UnaryExprOrTypeTraitExprClass:
Bldr.takeNodes(Pred);
VisitUnaryExprOrTypeTraitExpr(cast<UnaryExprOrTypeTraitExpr>(S),
Pred, Dst);
Bldr.addNodes(Dst);
break;
case Stmt::StmtExprClass: {
const 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.");
break;
}
if (Expr *LastExpr = dyn_cast<Expr>(*SE->getSubStmt()->body_rbegin())) {
ProgramStateRef state = Pred->getState();
Bldr.generateNode(SE, Pred,
state->BindExpr(SE, Pred->getLocationContext(),
state->getSVal(LastExpr,
Pred->getLocationContext())));
}
break;
}
case Stmt::UnaryOperatorClass: {
Bldr.takeNodes(Pred);
const UnaryOperator *U = cast<UnaryOperator>(S);
if (AMgr.options.eagerlyAssumeBinOpBifurcation && (U->getOpcode() == UO_LNot)) {
ExplodedNodeSet Tmp;
VisitUnaryOperator(U, Pred, Tmp);
evalEagerlyAssumeBinOpBifurcation(Dst, Tmp, U);
}
else
VisitUnaryOperator(U, Pred, Dst);
Bldr.addNodes(Dst);
break;
}
case Stmt::PseudoObjectExprClass: {
Bldr.takeNodes(Pred);
ProgramStateRef state = Pred->getState();
const PseudoObjectExpr *PE = cast<PseudoObjectExpr>(S);
if (const Expr *Result = PE->getResultExpr()) {
SVal V = state->getSVal(Result, Pred->getLocationContext());
Bldr.generateNode(S, Pred,
state->BindExpr(S, Pred->getLocationContext(), V));
}
else
Bldr.generateNode(S, Pred,
state->BindExpr(S, Pred->getLocationContext(),
UnknownVal()));
Bldr.addNodes(Dst);
break;
}
}
}
bool ExprEngine::replayWithoutInlining(ExplodedNode *N,
const LocationContext *CalleeLC) {
const StackFrameContext *CalleeSF = CalleeLC->getCurrentStackFrame();
const StackFrameContext *CallerSF = CalleeSF->getParent()->getCurrentStackFrame();
assert(CalleeSF && CallerSF);
ExplodedNode *BeforeProcessingCall = nullptr;
const Stmt *CE = CalleeSF->getCallSite();
// Find the first node before we started processing the call expression.
while (N) {
ProgramPoint L = N->getLocation();
BeforeProcessingCall = N;
N = N->pred_empty() ? nullptr : *(N->pred_begin());
// Skip the nodes corresponding to the inlined code.
if (L.getLocationContext()->getCurrentStackFrame() != CallerSF)
continue;
// We reached the caller. Find the node right before we started
// processing the call.
if (L.isPurgeKind())
continue;
if (L.getAs<PreImplicitCall>())
continue;
if (L.getAs<CallEnter>())
continue;
if (Optional<StmtPoint> SP = L.getAs<StmtPoint>())
if (SP->getStmt() == CE)
continue;
break;
}
if (!BeforeProcessingCall)
return false;
// TODO: Clean up the unneeded nodes.
// Build an Epsilon node from which we will restart the analyzes.
// Note that CE is permitted to be NULL!
ProgramPoint NewNodeLoc =
EpsilonPoint(BeforeProcessingCall->getLocationContext(), CE);
// Add the special flag to GDM to signal retrying with no inlining.
// Note, changing the state ensures that we are not going to cache out.
ProgramStateRef NewNodeState = BeforeProcessingCall->getState();
NewNodeState =
NewNodeState->set<ReplayWithoutInlining>(const_cast<Stmt *>(CE));
// Make the new node a successor of BeforeProcessingCall.
bool IsNew = false;
ExplodedNode *NewNode = G.getNode(NewNodeLoc, NewNodeState, false, &IsNew);
// We cached out at this point. Caching out is common due to us backtracking
// from the inlined function, which might spawn several paths.
if (!IsNew)
return true;
NewNode->addPredecessor(BeforeProcessingCall, G);
// Add the new node to the work list.
Engine.enqueueStmtNode(NewNode, CalleeSF->getCallSiteBlock(),
CalleeSF->getIndex());
NumTimesRetriedWithoutInlining++;
return true;
}
/// Block entrance. (Update counters).
void ExprEngine::processCFGBlockEntrance(const BlockEdge &L,
NodeBuilderWithSinks &nodeBuilder,
ExplodedNode *Pred) {
PrettyStackTraceLocationContext CrashInfo(Pred->getLocationContext());
// If this block is terminated by a loop and it has already been visited the
// maximum number of times, widen the loop.
unsigned int BlockCount = nodeBuilder.getContext().blockCount();
if (BlockCount == AMgr.options.maxBlockVisitOnPath - 1 &&
AMgr.options.shouldWidenLoops()) {
const Stmt *Term = nodeBuilder.getContext().getBlock()->getTerminator();
if (!(Term &&
(isa<ForStmt>(Term) || isa<WhileStmt>(Term) || isa<DoStmt>(Term))))
return;
// Widen.
const LocationContext *LCtx = Pred->getLocationContext();
ProgramStateRef WidenedState =
getWidenedLoopState(Pred->getState(), LCtx, BlockCount, Term);
nodeBuilder.generateNode(WidenedState, Pred);
return;
}
// FIXME: Refactor this into a checker.
if (BlockCount >= AMgr.options.maxBlockVisitOnPath) {
static SimpleProgramPointTag tag(TagProviderName, "Block count exceeded");
const ExplodedNode *Sink =
nodeBuilder.generateSink(Pred->getState(), Pred, &tag);
// Check if we stopped at the top level function or not.
// Root node should have the location context of the top most function.
const LocationContext *CalleeLC = Pred->getLocation().getLocationContext();
const LocationContext *CalleeSF = CalleeLC->getCurrentStackFrame();
const LocationContext *RootLC =
(*G.roots_begin())->getLocation().getLocationContext();
if (RootLC->getCurrentStackFrame() != CalleeSF) {
Engine.FunctionSummaries->markReachedMaxBlockCount(CalleeSF->getDecl());
// Re-run the call evaluation without inlining it, by storing the
// no-inlining policy in the state and enqueuing the new work item on
// the list. Replay should almost never fail. Use the stats to catch it
// if it does.
if ((!AMgr.options.NoRetryExhausted &&
replayWithoutInlining(Pred, CalleeLC)))
return;
NumMaxBlockCountReachedInInlined++;
} else
NumMaxBlockCountReached++;
// Make sink nodes as exhausted(for stats) only if retry failed.
Engine.blocksExhausted.push_back(std::make_pair(L, Sink));
}
}
//===----------------------------------------------------------------------===//
// Branch processing.
//===----------------------------------------------------------------------===//
/// 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(ProgramStateManager& StateMgr,
ProgramStateRef state,
const Stmt *Condition,
const LocationContext *LCtx,
ASTContext &Ctx) {
const Expr *Ex = dyn_cast<Expr>(Condition);
if (!Ex)
return UnknownVal();
uint64_t bits = 0;
bool bitsInit = false;
while (const CastExpr *CE = dyn_cast<CastExpr>(Ex)) {
QualType T = CE->getType();
if (!T->isIntegralOrEnumerationType())
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->isIntegralOrEnumerationType() ||
Ctx.getTypeSize(T) > bits)
return UnknownVal();
return state->getSVal(Ex, LCtx);
}
#ifndef NDEBUG
static const Stmt *getRightmostLeaf(const Stmt *Condition) {
while (Condition) {
const BinaryOperator *BO = dyn_cast<BinaryOperator>(Condition);
if (!BO || !BO->isLogicalOp()) {
return Condition;
}
Condition = BO->getRHS()->IgnoreParens();
}
return nullptr;
}
#endif
// Returns the condition the branch at the end of 'B' depends on and whose value
// has been evaluated within 'B'.
// In most cases, the terminator condition of 'B' will be evaluated fully in
// the last statement of 'B'; in those cases, the resolved condition is the
// given 'Condition'.
// If the condition of the branch is a logical binary operator tree, the CFG is
// optimized: in that case, we know that the expression formed by all but the
// rightmost leaf of the logical binary operator tree must be true, and thus
// the branch condition is at this point equivalent to the truth value of that
// rightmost leaf; the CFG block thus only evaluates this rightmost leaf
// expression in its final statement. As the full condition in that case was
// not evaluated, and is thus not in the SVal cache, we need to use that leaf
// expression to evaluate the truth value of the condition in the current state
// space.
static const Stmt *ResolveCondition(const Stmt *Condition,
const CFGBlock *B) {
if (const Expr *Ex = dyn_cast<Expr>(Condition))
Condition = Ex->IgnoreParens();
const BinaryOperator *BO = dyn_cast<BinaryOperator>(Condition);
if (!BO || !BO->isLogicalOp())
return Condition;
assert(!B->getTerminator().isTemporaryDtorsBranch() &&
"Temporary destructor branches handled by processBindTemporary.");
// For logical operations, we still have the case where some branches
// use the traditional "merge" approach and others sink the branch
// directly into the basic blocks representing the logical operation.
// We need to distinguish between those two cases here.
// The invariants are still shifting, but it is possible that the
// last element in a CFGBlock is not a CFGStmt. Look for the last
// CFGStmt as the value of the condition.
CFGBlock::const_reverse_iterator I = B->rbegin(), E = B->rend();
for (; I != E; ++I) {
CFGElement Elem = *I;
Optional<CFGStmt> CS = Elem.getAs<CFGStmt>();
if (!CS)
continue;
const Stmt *LastStmt = CS->getStmt();
assert(LastStmt == Condition || LastStmt == getRightmostLeaf(Condition));
return LastStmt;
}
llvm_unreachable("could not resolve condition");
}
void ExprEngine::processBranch(const Stmt *Condition, const Stmt *Term,
NodeBuilderContext& BldCtx,
ExplodedNode *Pred,
ExplodedNodeSet &Dst,
const CFGBlock *DstT,
const CFGBlock *DstF) {
assert((!Condition || !isa<CXXBindTemporaryExpr>(Condition)) &&
"CXXBindTemporaryExprs are handled by processBindTemporary.");
const LocationContext *LCtx = Pred->getLocationContext();
PrettyStackTraceLocationContext StackCrashInfo(LCtx);
currBldrCtx = &BldCtx;
// Check for NULL conditions; e.g. "for(;;)"
if (!Condition) {
BranchNodeBuilder NullCondBldr(Pred, Dst, BldCtx, DstT, DstF);
NullCondBldr.markInfeasible(false);
NullCondBldr.generateNode(Pred->getState(), true, Pred);
return;
}
if (const Expr *Ex = dyn_cast<Expr>(Condition))
Condition = Ex->IgnoreParens();
Condition = ResolveCondition(Condition, BldCtx.getBlock());
PrettyStackTraceLoc CrashInfo(getContext().getSourceManager(),
Condition->getLocStart(),
"Error evaluating branch");
ExplodedNodeSet CheckersOutSet;
getCheckerManager().runCheckersForBranchCondition(Condition, CheckersOutSet,
Pred, *this);
// We generated only sinks.
if (CheckersOutSet.empty())
return;
BranchNodeBuilder builder(CheckersOutSet, Dst, BldCtx, DstT, DstF);
for (NodeBuilder::iterator I = CheckersOutSet.begin(),
E = CheckersOutSet.end(); E != I; ++I) {
ExplodedNode *PredI = *I;
if (PredI->isSink())
continue;
ProgramStateRef PrevState = PredI->getState();
SVal X = PrevState->getSVal(Condition, PredI->getLocationContext());
if (X.isUnknownOrUndef()) {
// Give it a chance to recover from unknown.
if (const Expr *Ex = dyn_cast<Expr>(Condition)) {
if (Ex->getType()->isIntegralOrEnumerationType()) {
// 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(),
PrevState, Condition,
PredI->getLocationContext(),
getContext());
if (!recovered.isUnknown()) {
X = recovered;
}
}
}
}
// If the condition is still unknown, give up.
if (X.isUnknownOrUndef()) {
builder.generateNode(PrevState, true, PredI);
builder.generateNode(PrevState, false, PredI);
continue;
}
DefinedSVal V = X.castAs<DefinedSVal>();
ProgramStateRef StTrue, StFalse;
std::tie(StTrue, StFalse) = PrevState->assume(V);
// Process the true branch.
if (builder.isFeasible(true)) {
if (StTrue)
builder.generateNode(StTrue, true, PredI);
else
builder.markInfeasible(true);
}
// Process the false branch.
if (builder.isFeasible(false)) {
if (StFalse)
builder.generateNode(StFalse, false, PredI);
else
builder.markInfeasible(false);
}
}
currBldrCtx = nullptr;
}
/// The GDM component containing the set of global variables which have been
/// previously initialized with explicit initializers.
REGISTER_TRAIT_WITH_PROGRAMSTATE(InitializedGlobalsSet,
llvm::ImmutableSet<const VarDecl *>)
void ExprEngine::processStaticInitializer(const DeclStmt *DS,
NodeBuilderContext &BuilderCtx,
ExplodedNode *Pred,
clang::ento::ExplodedNodeSet &Dst,
const CFGBlock *DstT,
const CFGBlock *DstF) {
PrettyStackTraceLocationContext CrashInfo(Pred->getLocationContext());
currBldrCtx = &BuilderCtx;
const VarDecl *VD = cast<VarDecl>(DS->getSingleDecl());
ProgramStateRef state = Pred->getState();
bool initHasRun = state->contains<InitializedGlobalsSet>(VD);
BranchNodeBuilder builder(Pred, Dst, BuilderCtx, DstT, DstF);
if (!initHasRun) {
state = state->add<InitializedGlobalsSet>(VD);
}
builder.generateNode(state, initHasRun, Pred);
builder.markInfeasible(!initHasRun);
currBldrCtx = nullptr;
}
/// processIndirectGoto - Called by CoreEngine. Used to generate successor
/// nodes by processing the 'effects' of a computed goto jump.
void ExprEngine::processIndirectGoto(IndirectGotoNodeBuilder &builder) {
ProgramStateRef state = builder.getState();
SVal V = state->getSVal(builder.getTarget(), builder.getLocationContext());
// Three possibilities:
//
// (1) We know the computed label.
// (2) The label is NULL (or some other constant), or Undefined.
// (3) We have no clue about the label. Dispatch to all targets.
//
typedef IndirectGotoNodeBuilder::iterator iterator;
if (Optional<loc::GotoLabel> LV = V.getAs<loc::GotoLabel>()) {
const LabelDecl *L = LV->getLabel();
for (iterator I = builder.begin(), E = builder.end(); I != E; ++I) {
if (I.getLabel() == L) {
builder.generateNode(I, state);
return;
}
}
llvm_unreachable("No block with label.");
}
if (V.getAs<loc::ConcreteInt>() || V.getAs<UndefinedVal>()) {
// 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);
}
#if 0
static bool stackFrameDoesNotContainInitializedTemporaries(ExplodedNode &Pred) {
const StackFrameContext* Frame = Pred.getStackFrame();
const llvm::ImmutableSet<CXXBindTemporaryContext> &Set =
Pred.getState()->get<InitializedTemporariesSet>();
return std::find_if(Set.begin(), Set.end(),
[&](const CXXBindTemporaryContext &Ctx) {
if (Ctx.second == Frame) {
Ctx.first->dump();
llvm::errs() << "\n";
}
return Ctx.second == Frame;
}) == Set.end();
}
#endif
void ExprEngine::processBeginOfFunction(NodeBuilderContext &BC,
ExplodedNode *Pred,
ExplodedNodeSet &Dst,
const BlockEdge &L) {
SaveAndRestore<const NodeBuilderContext *> NodeContextRAII(currBldrCtx, &BC);
getCheckerManager().runCheckersForBeginFunction(Dst, L, Pred, *this);
}
/// ProcessEndPath - Called by CoreEngine. Used to generate end-of-path
/// nodes when the control reaches the end of a function.
void ExprEngine::processEndOfFunction(NodeBuilderContext& BC,
ExplodedNode *Pred,
const ReturnStmt *RS) {
// FIXME: Assert that stackFrameDoesNotContainInitializedTemporaries(*Pred)).
// We currently cannot enable this assert, as lifetime extended temporaries
// are not modelled correctly.
PrettyStackTraceLocationContext CrashInfo(Pred->getLocationContext());
StateMgr.EndPath(Pred->getState());
ExplodedNodeSet Dst;
if (Pred->getLocationContext()->inTopFrame()) {
// Remove dead symbols.
ExplodedNodeSet AfterRemovedDead;
removeDeadOnEndOfFunction(BC, Pred, AfterRemovedDead);
// Notify checkers.
for (ExplodedNodeSet::iterator I = AfterRemovedDead.begin(),
E = AfterRemovedDead.end(); I != E; ++I) {
getCheckerManager().runCheckersForEndFunction(BC, Dst, *I, *this);
}
} else {
getCheckerManager().runCheckersForEndFunction(BC, Dst, Pred, *this);
}
Engine.enqueueEndOfFunction(Dst, RS);
}
/// ProcessSwitch - Called by CoreEngine. Used to generate successor
/// nodes by processing the 'effects' of a switch statement.
void ExprEngine::processSwitch(SwitchNodeBuilder& builder) {
typedef SwitchNodeBuilder::iterator iterator;
ProgramStateRef state = builder.getState();
const Expr *CondE = builder.getCondition();
SVal CondV_untested = state->getSVal(CondE, builder.getLocationContext());
if (CondV_untested.isUndef()) {
//ExplodedNode* N = builder.generateDefaultCaseNode(state, true);
// FIXME: add checker
//UndefBranches.insert(N);
return;
}
DefinedOrUnknownSVal CondV = CondV_untested.castAs<DefinedOrUnknownSVal>();
ProgramStateRef DefaultSt = state;
iterator I = builder.begin(), EI = builder.end();
bool defaultIsFeasible = I == EI;
for ( ; I != EI; ++I) {
// Successor may be pruned out during CFG construction.
if (!I.getBlock())
continue;
const CaseStmt *Case = I.getCase();
// Evaluate the LHS of the case value.
llvm::APSInt V1 = Case->getLHS()->EvaluateKnownConstInt(getContext());
assert(V1.getBitWidth() == getContext().getTypeSize(CondE->getType()));
// Get the RHS of the case, if it exists.
llvm::APSInt V2;
if (const Expr *E = Case->getRHS())
V2 = E->EvaluateKnownConstInt(getContext());
else
V2 = V1;
ProgramStateRef StateCase;
if (Optional<NonLoc> NL = CondV.getAs<NonLoc>())
std::tie(StateCase, DefaultSt) =
DefaultSt->assumeInclusiveRange(*NL, V1, V2);
else // UnknownVal
StateCase = DefaultSt;
if (StateCase)
builder.generateCaseStmtNode(I, StateCase);
// Now "assume" that the case doesn't match. Add this state
// to the default state (if it is feasible).
if (DefaultSt)
defaultIsFeasible = true;
else {
defaultIsFeasible = false;
break;
}
}
if (!defaultIsFeasible)
return;
// If we have switch(enum value), the default branch is not
// feasible if all of the enum constants not covered by 'case:' statements
// are not feasible values for the switch condition.
//
// Note that this isn't as accurate as it could be. Even if there isn't
// a case for a particular enum value as long as that enum value isn't
// feasible then it shouldn't be considered for making 'default:' reachable.
const SwitchStmt *SS = builder.getSwitch();
const Expr *CondExpr = SS->getCond()->IgnoreParenImpCasts();
if (CondExpr->getType()->getAs<EnumType>()) {
if (SS->isAllEnumCasesCovered())
return;
}
builder.generateDefaultCaseNode(DefaultSt);
}
//===----------------------------------------------------------------------===//
// Transfer functions: Loads and stores.
//===----------------------------------------------------------------------===//
void ExprEngine::VisitCommonDeclRefExpr(const Expr *Ex, const NamedDecl *D,
ExplodedNode *Pred,
ExplodedNodeSet &Dst) {
StmtNodeBuilder Bldr(Pred, Dst, *currBldrCtx);
ProgramStateRef state = Pred->getState();
const LocationContext *LCtx = Pred->getLocationContext();
if (const VarDecl *VD = dyn_cast<VarDecl>(D)) {
// C permits "extern void v", and if you cast the address to a valid type,
// you can even do things with it. We simply pretend
assert(Ex->isGLValue() || VD->getType()->isVoidType());
const LocationContext *LocCtxt = Pred->getLocationContext();
const Decl *D = LocCtxt->getDecl();
const auto *MD = D ? dyn_cast<CXXMethodDecl>(D) : nullptr;
const auto *DeclRefEx = dyn_cast<DeclRefExpr>(Ex);
SVal V;
bool IsReference;
if (AMgr.options.shouldInlineLambdas() && DeclRefEx &&
DeclRefEx->refersToEnclosingVariableOrCapture() && MD &&
MD->getParent()->isLambda()) {
// Lookup the field of the lambda.
const CXXRecordDecl *CXXRec = MD->getParent();
llvm::DenseMap<const VarDecl *, FieldDecl *> LambdaCaptureFields;
FieldDecl *LambdaThisCaptureField;
CXXRec->getCaptureFields(LambdaCaptureFields, LambdaThisCaptureField);
const FieldDecl *FD = LambdaCaptureFields[VD];
if (!FD) {
// When a constant is captured, sometimes no corresponding field is
// created in the lambda object.
assert(VD->getType().isConstQualified());
V = state->getLValue(VD, LocCtxt);
IsReference = false;
} else {
Loc CXXThis =
svalBuilder.getCXXThis(MD, LocCtxt->getCurrentStackFrame());
SVal CXXThisVal = state->getSVal(CXXThis);
V = state->getLValue(FD, CXXThisVal);
IsReference = FD->getType()->isReferenceType();
}
} else {
V = state->getLValue(VD, LocCtxt);
IsReference = VD->getType()->isReferenceType();
}
// For references, the 'lvalue' is the pointer address stored in the
// reference region.
if (IsReference) {
if (const MemRegion *R = V.getAsRegion())
V = state->getSVal(R);
else
V = UnknownVal();
}
Bldr.generateNode(Ex, Pred, state->BindExpr(Ex, LCtx, V), nullptr,
ProgramPoint::PostLValueKind);
return;
}
if (const EnumConstantDecl *ED = dyn_cast<EnumConstantDecl>(D)) {
assert(!Ex->isGLValue());
SVal V = svalBuilder.makeIntVal(ED->getInitVal());
Bldr.generateNode(Ex, Pred, state->BindExpr(Ex, LCtx, V));
return;
}
if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
SVal V = svalBuilder.getFunctionPointer(FD);
Bldr.generateNode(Ex, Pred, state->BindExpr(Ex, LCtx, V), nullptr,
ProgramPoint::PostLValueKind);
return;
}
if (isa<FieldDecl>(D)) {
// FIXME: Compute lvalue of field pointers-to-member.
// Right now we just use a non-null void pointer, so that it gives proper
// results in boolean contexts.
SVal V = svalBuilder.conjureSymbolVal(Ex, LCtx, getContext().VoidPtrTy,
currBldrCtx->blockCount());
state = state->assume(V.castAs<DefinedOrUnknownSVal>(), true);
Bldr.generateNode(Ex, Pred, state->BindExpr(Ex, LCtx, V), nullptr,
ProgramPoint::PostLValueKind);
return;
}
llvm_unreachable("Support for this Decl not implemented.");
}
/// VisitArraySubscriptExpr - Transfer function for array accesses
void ExprEngine::VisitLvalArraySubscriptExpr(const ArraySubscriptExpr *A,
ExplodedNode *Pred,
ExplodedNodeSet &Dst){
const Expr *Base = A->getBase()->IgnoreParens();
const Expr *Idx = A->getIdx()->IgnoreParens();
ExplodedNodeSet CheckerPreStmt;
getCheckerManager().runCheckersForPreStmt(CheckerPreStmt, Pred, A, *this);
ExplodedNodeSet EvalSet;
StmtNodeBuilder Bldr(CheckerPreStmt, EvalSet, *currBldrCtx);
assert(A->isGLValue() ||
(!AMgr.getLangOpts().CPlusPlus &&
A->getType().isCForbiddenLValueType()));
for (auto *Node : CheckerPreStmt) {
const LocationContext *LCtx = Node->getLocationContext();
ProgramStateRef state = Node->getState();
SVal V = state->getLValue(A->getType(),
state->getSVal(Idx, LCtx),
state->getSVal(Base, LCtx));
Bldr.generateNode(A, Node, state->BindExpr(A, LCtx, V), nullptr,
ProgramPoint::PostLValueKind);
}
getCheckerManager().runCheckersForPostStmt(Dst, EvalSet, A, *this);
}
/// VisitMemberExpr - Transfer function for member expressions.
void ExprEngine::VisitMemberExpr(const MemberExpr *M, ExplodedNode *Pred,
ExplodedNodeSet &Dst) {
// FIXME: Prechecks eventually go in ::Visit().
ExplodedNodeSet CheckedSet;
getCheckerManager().runCheckersForPreStmt(CheckedSet, Pred, M, *this);
ExplodedNodeSet EvalSet;
ValueDecl *Member = M->getMemberDecl();
// Handle static member variables and enum constants accessed via
// member syntax.
if (isa<VarDecl>(Member) || isa<EnumConstantDecl>(Member)) {
ExplodedNodeSet Dst;
for (ExplodedNodeSet::iterator I = CheckedSet.begin(), E = CheckedSet.end();
I != E; ++I) {
VisitCommonDeclRefExpr(M, Member, Pred, EvalSet);
}
} else {
StmtNodeBuilder Bldr(CheckedSet, EvalSet, *currBldrCtx);
ExplodedNodeSet Tmp;
for (ExplodedNodeSet::iterator I = CheckedSet.begin(), E = CheckedSet.end();
I != E; ++I) {
ProgramStateRef state = (*I)->getState();
const LocationContext *LCtx = (*I)->getLocationContext();
Expr *BaseExpr = M->getBase();
// Handle C++ method calls.
if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(Member)) {
if (MD->isInstance())
state = createTemporaryRegionIfNeeded(state, LCtx, BaseExpr);
SVal MDVal = svalBuilder.getFunctionPointer(MD);
state = state->BindExpr(M, LCtx, MDVal);
Bldr.generateNode(M, *I, state);
continue;
}
// Handle regular struct fields / member variables.
state = createTemporaryRegionIfNeeded(state, LCtx, BaseExpr);
SVal baseExprVal = state->getSVal(BaseExpr, LCtx);
FieldDecl *field = cast<FieldDecl>(Member);
SVal L = state->getLValue(field, baseExprVal);
if (M->isGLValue() || M->getType()->isArrayType()) {
// We special-case rvalues of array type because the analyzer cannot
// reason about them, since we expect all regions to be wrapped in Locs.
// We instead treat these as lvalues and assume that they will decay to
// pointers as soon as they are used.
if (!M->isGLValue()) {
assert(M->getType()->isArrayType());
const ImplicitCastExpr *PE =
dyn_cast<ImplicitCastExpr>((*I)->getParentMap().getParentIgnoreParens(M));
if (!PE || PE->getCastKind() != CK_ArrayToPointerDecay) {
llvm_unreachable("should always be wrapped in ArrayToPointerDecay");
}
}
if (field->getType()->isReferenceType()) {
if (const MemRegion *R = L.getAsRegion())
L = state->getSVal(R);
else
L = UnknownVal();
}
Bldr.generateNode(M, *I, state->BindExpr(M, LCtx, L), nullptr,
ProgramPoint::PostLValueKind);
} else {
Bldr.takeNodes(*I);
evalLoad(Tmp, M, M, *I, state, L);
Bldr.addNodes(Tmp);
}
}
}
getCheckerManager().runCheckersForPostStmt(Dst, EvalSet, M, *this);
}
void ExprEngine::VisitAtomicExpr(const AtomicExpr *AE, ExplodedNode *Pred,
ExplodedNodeSet &Dst) {
ExplodedNodeSet AfterPreSet;
getCheckerManager().runCheckersForPreStmt(AfterPreSet, Pred, AE, *this);
// For now, treat all the arguments to C11 atomics as escaping.
// FIXME: Ideally we should model the behavior of the atomics precisely here.
ExplodedNodeSet AfterInvalidateSet;
StmtNodeBuilder Bldr(AfterPreSet, AfterInvalidateSet, *currBldrCtx);
for (ExplodedNodeSet::iterator I = AfterPreSet.begin(), E = AfterPreSet.end();
I != E; ++I) {
ProgramStateRef State = (*I)->getState();
const LocationContext *LCtx = (*I)->getLocationContext();
SmallVector<SVal, 8> ValuesToInvalidate;
for (unsigned SI = 0, Count = AE->getNumSubExprs(); SI != Count; SI++) {
const Expr *SubExpr = AE->getSubExprs()[SI];
SVal SubExprVal = State->getSVal(SubExpr, LCtx);
ValuesToInvalidate.push_back(SubExprVal);
}
State = State->invalidateRegions(ValuesToInvalidate, AE,
currBldrCtx->blockCount(),
LCtx,
/*CausedByPointerEscape*/true,
/*Symbols=*/nullptr);
SVal ResultVal = UnknownVal();
State = State->BindExpr(AE, LCtx, ResultVal);
Bldr.generateNode(AE, *I, State, nullptr,
ProgramPoint::PostStmtKind);
}
getCheckerManager().runCheckersForPostStmt(Dst, AfterInvalidateSet, AE, *this);
}
namespace {
class CollectReachableSymbolsCallback final : public SymbolVisitor {
InvalidatedSymbols Symbols;
public:
CollectReachableSymbolsCallback(ProgramStateRef State) {}
const InvalidatedSymbols &getSymbols() const { return Symbols; }
bool VisitSymbol(SymbolRef Sym) override {
Symbols.insert(Sym);
return true;
}
};
} // end anonymous namespace
// A value escapes in three possible cases:
// (1) We are binding to something that is not a memory region.
// (2) We are binding to a MemrRegion that does not have stack storage.
// (3) We are binding to a MemRegion with stack storage that the store
// does not understand.
ProgramStateRef ExprEngine::processPointerEscapedOnBind(ProgramStateRef State,
SVal Loc, SVal Val) {
// Are we storing to something that causes the value to "escape"?
bool escapes = true;
// TODO: Move to StoreManager.
if (Optional<loc::MemRegionVal> regionLoc = Loc.getAs<loc::MemRegionVal>()) {
escapes = !regionLoc->getRegion()->hasStackStorage();
if (!escapes) {
// To test (3), generate a new state with the binding added. If it is
// the same state, then it escapes (since the store cannot represent
// the binding).
// Do this only if we know that the store is not supposed to generate the
// same state.
SVal StoredVal = State->getSVal(regionLoc->getRegion());
if (StoredVal != Val)
escapes = (State == (State->bindLoc(*regionLoc, Val)));
}
}
// If our store can represent the binding and we aren't storing to something
// that doesn't have local storage then just return and have the simulation
// state continue as is.
if (!escapes)
return State;
// Otherwise, find all symbols referenced by 'val' that we are tracking
// and stop tracking them.
CollectReachableSymbolsCallback Scanner =
State->scanReachableSymbols<CollectReachableSymbolsCallback>(Val);
const InvalidatedSymbols &EscapedSymbols = Scanner.getSymbols();
State = getCheckerManager().runCheckersForPointerEscape(State,
EscapedSymbols,
/*CallEvent*/ nullptr,
PSK_EscapeOnBind,
nullptr);
return State;
}
ProgramStateRef
ExprEngine::notifyCheckersOfPointerEscape(ProgramStateRef State,
const InvalidatedSymbols *Invalidated,
ArrayRef<const MemRegion *> ExplicitRegions,
ArrayRef<const MemRegion *> Regions,
const CallEvent *Call,
RegionAndSymbolInvalidationTraits &ITraits) {
if (!Invalidated || Invalidated->empty())
return State;
if (!Call)
return getCheckerManager().runCheckersForPointerEscape(State,
*Invalidated,
nullptr,
PSK_EscapeOther,
&ITraits);
// If the symbols were invalidated by a call, we want to find out which ones
// were invalidated directly due to being arguments to the call.
InvalidatedSymbols SymbolsDirectlyInvalidated;
for (ArrayRef<const MemRegion *>::iterator I = ExplicitRegions.begin(),
E = ExplicitRegions.end(); I != E; ++I) {
if (const SymbolicRegion *R = (*I)->StripCasts()->getAs<SymbolicRegion>())
SymbolsDirectlyInvalidated.insert(R->getSymbol());
}
InvalidatedSymbols SymbolsIndirectlyInvalidated;
for (InvalidatedSymbols::const_iterator I=Invalidated->begin(),
E = Invalidated->end(); I!=E; ++I) {
SymbolRef sym = *I;
if (SymbolsDirectlyInvalidated.count(sym))
continue;
SymbolsIndirectlyInvalidated.insert(sym);
}
if (!SymbolsDirectlyInvalidated.empty())
State = getCheckerManager().runCheckersForPointerEscape(State,
SymbolsDirectlyInvalidated, Call, PSK_DirectEscapeOnCall, &ITraits);
// Notify about the symbols that get indirectly invalidated by the call.
if (!SymbolsIndirectlyInvalidated.empty())
State = getCheckerManager().runCheckersForPointerEscape(State,
SymbolsIndirectlyInvalidated, Call, PSK_IndirectEscapeOnCall, &ITraits);
return State;
}
/// evalBind - Handle the semantics of binding a value to a specific location.
/// This method is used by evalStore and (soon) VisitDeclStmt, and others.
void ExprEngine::evalBind(ExplodedNodeSet &Dst, const Stmt *StoreE,
ExplodedNode *Pred,
SVal location, SVal Val,
bool atDeclInit, const ProgramPoint *PP) {
const LocationContext *LC = Pred->getLocationContext();
PostStmt PS(StoreE, LC);
if (!PP)
PP = &PS;
// Do a previsit of the bind.
ExplodedNodeSet CheckedSet;
getCheckerManager().runCheckersForBind(CheckedSet, Pred, location, Val,
StoreE, *this, *PP);
StmtNodeBuilder Bldr(CheckedSet, Dst, *currBldrCtx);
// If the location is not a 'Loc', it will already be handled by
// the checkers. There is nothing left to do.
if (!location.getAs<Loc>()) {
const ProgramPoint L = PostStore(StoreE, LC, /*Loc*/nullptr,
/*tag*/nullptr);
ProgramStateRef state = Pred->getState();
state = processPointerEscapedOnBind(state, location, Val);
Bldr.generateNode(L, state, Pred);
return;
}
for (ExplodedNodeSet::iterator I = CheckedSet.begin(), E = CheckedSet.end();
I!=E; ++I) {
ExplodedNode *PredI = *I;
ProgramStateRef state = PredI->getState();
state = processPointerEscapedOnBind(state, location, Val);
// When binding the value, pass on the hint that this is a initialization.
// For initializations, we do not need to inform clients of region
// changes.
state = state->bindLoc(location.castAs<Loc>(),
Val, /* notifyChanges = */ !atDeclInit);
const MemRegion *LocReg = nullptr;
if (Optional<loc::MemRegionVal> LocRegVal =
location.getAs<loc::MemRegionVal>()) {
LocReg = LocRegVal->getRegion();
}
const ProgramPoint L = PostStore(StoreE, LC, LocReg, nullptr);
Bldr.generateNode(L, state, PredI);
}
}
/// evalStore - Handle the semantics of a store via an assignment.
/// @param Dst The node set to store generated state nodes
/// @param AssignE The assignment expression if the store happens in an
/// assignment.
/// @param LocationE The location expression that is stored to.
/// @param state The current simulation state
/// @param location The location to store the value
/// @param Val The value to be stored
void ExprEngine::evalStore(ExplodedNodeSet &Dst, const Expr *AssignE,
const Expr *LocationE,
ExplodedNode *Pred,
ProgramStateRef state, SVal location, SVal Val,
const ProgramPointTag *tag) {
// Proceed with the store. We use AssignE as the anchor for the PostStore
// ProgramPoint if it is non-NULL, and LocationE otherwise.
const Expr *StoreE = AssignE ? AssignE : LocationE;
// Evaluate the location (checks for bad dereferences).
ExplodedNodeSet Tmp;
evalLocation(Tmp, AssignE, LocationE, Pred, state, location, tag, false);
if (Tmp.empty())
return;
if (location.isUndef())
return;
for (ExplodedNodeSet::iterator NI=Tmp.begin(), NE=Tmp.end(); NI!=NE; ++NI)
evalBind(Dst, StoreE, *NI, location, Val, false);
}
void ExprEngine::evalLoad(ExplodedNodeSet &Dst,
const Expr *NodeEx,
const Expr *BoundEx,
ExplodedNode *Pred,
ProgramStateRef state,
SVal location,
const ProgramPointTag *tag,
QualType LoadTy)
{
assert(!location.getAs<NonLoc>() && "location cannot be a NonLoc.");
// 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 TypedValueRegion *TR =
dyn_cast_or_null<TypedValueRegion>(location.getAsRegion())) {
QualType ValTy = TR->getValueType();
if (const ReferenceType *RT = ValTy->getAs<ReferenceType>()) {
static SimpleProgramPointTag
loadReferenceTag(TagProviderName, "Load Reference");
ExplodedNodeSet Tmp;
evalLoadCommon(Tmp, NodeEx, BoundEx, 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 = (*I)->getState();
location = state->getSVal(BoundEx, (*I)->getLocationContext());
evalLoadCommon(Dst, NodeEx, BoundEx, *I, state, location, tag, LoadTy);
}
return;
}
}
evalLoadCommon(Dst, NodeEx, BoundEx, Pred, state, location, tag, LoadTy);
}
void ExprEngine::evalLoadCommon(ExplodedNodeSet &Dst,
const Expr *NodeEx,
const Expr *BoundEx,
ExplodedNode *Pred,
ProgramStateRef state,
SVal location,
const ProgramPointTag *tag,
QualType LoadTy) {
assert(NodeEx);
assert(BoundEx);
// Evaluate the location (checks for bad dereferences).
ExplodedNodeSet Tmp;
evalLocation(Tmp, NodeEx, BoundEx, Pred, state, location, tag, true);
if (Tmp.empty())
return;
StmtNodeBuilder Bldr(Tmp, Dst, *currBldrCtx);
if (location.isUndef())
return;
// Proceed with the load.
for (ExplodedNodeSet::iterator NI=Tmp.begin(), NE=Tmp.end(); NI!=NE; ++NI) {
state = (*NI)->getState();
const LocationContext *LCtx = (*NI)->getLocationContext();
SVal V = UnknownVal();
if (location.isValid()) {
if (LoadTy.isNull())
LoadTy = BoundEx->getType();
V = state->getSVal(location.castAs<Loc>(), LoadTy);
}
Bldr.generateNode(NodeEx, *NI, state->BindExpr(BoundEx, LCtx, V), tag,
ProgramPoint::PostLoadKind);
}
}
void ExprEngine::evalLocation(ExplodedNodeSet &Dst,
const Stmt *NodeEx,
const Stmt *BoundEx,
ExplodedNode *Pred,
ProgramStateRef state,
SVal location,
const ProgramPointTag *tag,
bool isLoad) {
StmtNodeBuilder BldrTop(Pred, Dst, *currBldrCtx);
// Early checks for performance reason.
if (location.isUnknown()) {
return;
}
ExplodedNodeSet Src;
BldrTop.takeNodes(Pred);
StmtNodeBuilder Bldr(Pred, Src, *currBldrCtx);
if (Pred->getState() != state) {
// Associate this new state with an ExplodedNode.
// FIXME: If I pass null tag, the graph is incorrect, e.g for
// int *p;
// p = 0;
// *p = 0xDEADBEEF;
// "p = 0" is not noted as "Null pointer value stored to 'p'" but
// instead "int *p" is noted as
// "Variable 'p' initialized to a null pointer value"
static SimpleProgramPointTag tag(TagProviderName, "Location");
Bldr.generateNode(NodeEx, Pred, state, &tag);
}
ExplodedNodeSet Tmp;
getCheckerManager().runCheckersForLocation(Tmp, Src, location, isLoad,
NodeEx, BoundEx, *this);
BldrTop.addNodes(Tmp);
}
std::pair<const ProgramPointTag *, const ProgramPointTag*>
ExprEngine::geteagerlyAssumeBinOpBifurcationTags() {
static SimpleProgramPointTag
eagerlyAssumeBinOpBifurcationTrue(TagProviderName,
"Eagerly Assume True"),
eagerlyAssumeBinOpBifurcationFalse(TagProviderName,
"Eagerly Assume False");
return std::make_pair(&eagerlyAssumeBinOpBifurcationTrue,