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llvm-project/clang/lib/StaticAnalyzer/Core/ExprEngineCXX.cpp

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//===- ExprEngineCXX.cpp - ExprEngine support for C++ -----------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file defines the C++ expression evaluation engine.
//
//===----------------------------------------------------------------------===//
#include "clang/StaticAnalyzer/Core/PathSensitive/ExprEngine.h"
#include "clang/Analysis/ConstructionContext.h"
#include "clang/AST/DeclCXX.h"
#include "clang/AST/StmtCXX.h"
#include "clang/AST/ParentMap.h"
#include "clang/Basic/PrettyStackTrace.h"
#include "clang/StaticAnalyzer/Core/CheckerManager.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/AnalysisManager.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h"
using namespace clang;
using namespace ento;
void ExprEngine::CreateCXXTemporaryObject(const MaterializeTemporaryExpr *ME,
ExplodedNode *Pred,
ExplodedNodeSet &Dst) {
StmtNodeBuilder Bldr(Pred, Dst, *currBldrCtx);
const Expr *tempExpr = ME->getSubExpr()->IgnoreParens();
ProgramStateRef state = Pred->getState();
const LocationContext *LCtx = Pred->getLocationContext();
state = createTemporaryRegionIfNeeded(state, LCtx, tempExpr, ME);
Bldr.generateNode(ME, Pred, state);
}
// FIXME: This is the sort of code that should eventually live in a Core
// checker rather than as a special case in ExprEngine.
void ExprEngine::performTrivialCopy(NodeBuilder &Bldr, ExplodedNode *Pred,
const CallEvent &Call) {
SVal ThisVal;
bool AlwaysReturnsLValue;
const CXXRecordDecl *ThisRD = nullptr;
if (const CXXConstructorCall *Ctor = dyn_cast<CXXConstructorCall>(&Call)) {
assert(Ctor->getDecl()->isTrivial());
assert(Ctor->getDecl()->isCopyOrMoveConstructor());
ThisVal = Ctor->getCXXThisVal();
ThisRD = Ctor->getDecl()->getParent();
AlwaysReturnsLValue = false;
} else {
assert(cast<CXXMethodDecl>(Call.getDecl())->isTrivial());
assert(cast<CXXMethodDecl>(Call.getDecl())->getOverloadedOperator() ==
OO_Equal);
ThisVal = cast<CXXInstanceCall>(Call).getCXXThisVal();
ThisRD = cast<CXXMethodDecl>(Call.getDecl())->getParent();
AlwaysReturnsLValue = true;
}
assert(ThisRD);
if (ThisRD->isEmpty()) {
// Do nothing for empty classes. Otherwise it'd retrieve an UnknownVal
// and bind it and RegionStore would think that the actual value
// in this region at this offset is unknown.
return;
}
const LocationContext *LCtx = Pred->getLocationContext();
ExplodedNodeSet Dst;
Bldr.takeNodes(Pred);
SVal V = Call.getArgSVal(0);
// If the value being copied is not unknown, load from its location to get
// an aggregate rvalue.
if (Optional<Loc> L = V.getAs<Loc>())
V = Pred->getState()->getSVal(*L);
else
assert(V.isUnknownOrUndef());
const Expr *CallExpr = Call.getOriginExpr();
evalBind(Dst, CallExpr, Pred, ThisVal, V, true);
PostStmt PS(CallExpr, LCtx);
for (ExplodedNodeSet::iterator I = Dst.begin(), E = Dst.end();
I != E; ++I) {
ProgramStateRef State = (*I)->getState();
if (AlwaysReturnsLValue)
State = State->BindExpr(CallExpr, LCtx, ThisVal);
else
State = bindReturnValue(Call, LCtx, State);
Bldr.generateNode(PS, State, *I);
}
}
SVal ExprEngine::makeZeroElementRegion(ProgramStateRef State, SVal LValue,
QualType &Ty, bool &IsArray) {
SValBuilder &SVB = State->getStateManager().getSValBuilder();
ASTContext &Ctx = SVB.getContext();
while (const ArrayType *AT = Ctx.getAsArrayType(Ty)) {
Ty = AT->getElementType();
LValue = State->getLValue(Ty, SVB.makeZeroArrayIndex(), LValue);
IsArray = true;
}
return LValue;
}
std::pair<ProgramStateRef, SVal> ExprEngine::handleConstructionContext(
const Expr *E, ProgramStateRef State, const LocationContext *LCtx,
const ConstructionContext *CC, EvalCallOptions &CallOpts) {
SValBuilder &SVB = getSValBuilder();
MemRegionManager &MRMgr = SVB.getRegionManager();
ASTContext &ACtx = SVB.getContext();
// See if we're constructing an existing region by looking at the
// current construction context.
if (CC) {
switch (CC->getKind()) {
case ConstructionContext::CXX17ElidedCopyVariableKind:
case ConstructionContext::SimpleVariableKind: {
const auto *DSCC = cast<VariableConstructionContext>(CC);
const auto *DS = DSCC->getDeclStmt();
const auto *Var = cast<VarDecl>(DS->getSingleDecl());
SVal LValue = State->getLValue(Var, LCtx);
QualType Ty = Var->getType();
LValue =
makeZeroElementRegion(State, LValue, Ty, CallOpts.IsArrayCtorOrDtor);
State =
addObjectUnderConstruction(State, DSCC->getDeclStmt(), LCtx, LValue);
return std::make_pair(State, LValue);
}
case ConstructionContext::CXX17ElidedCopyConstructorInitializerKind:
case ConstructionContext::SimpleConstructorInitializerKind: {
const auto *ICC = cast<ConstructorInitializerConstructionContext>(CC);
const auto *Init = ICC->getCXXCtorInitializer();
assert(Init->isAnyMemberInitializer());
const CXXMethodDecl *CurCtor = cast<CXXMethodDecl>(LCtx->getDecl());
Loc ThisPtr =
SVB.getCXXThis(CurCtor, LCtx->getStackFrame());
SVal ThisVal = State->getSVal(ThisPtr);
const ValueDecl *Field;
SVal FieldVal;
if (Init->isIndirectMemberInitializer()) {
Field = Init->getIndirectMember();
FieldVal = State->getLValue(Init->getIndirectMember(), ThisVal);
} else {
Field = Init->getMember();
FieldVal = State->getLValue(Init->getMember(), ThisVal);
}
QualType Ty = Field->getType();
FieldVal = makeZeroElementRegion(State, FieldVal, Ty,
CallOpts.IsArrayCtorOrDtor);
State = addObjectUnderConstruction(State, Init, LCtx, FieldVal);
return std::make_pair(State, FieldVal);
}
case ConstructionContext::NewAllocatedObjectKind: {
if (AMgr.getAnalyzerOptions().MayInlineCXXAllocator) {
const auto *NECC = cast<NewAllocatedObjectConstructionContext>(CC);
const auto *NE = NECC->getCXXNewExpr();
SVal V = *getObjectUnderConstruction(State, NE, LCtx);
if (const SubRegion *MR =
dyn_cast_or_null<SubRegion>(V.getAsRegion())) {
if (NE->isArray()) {
// TODO: In fact, we need to call the constructor for every
// allocated element, not just the first one!
CallOpts.IsArrayCtorOrDtor = true;
return std::make_pair(
State, loc::MemRegionVal(getStoreManager().GetElementZeroRegion(
MR, NE->getType()->getPointeeType())));
}
return std::make_pair(State, V);
}
// TODO: Detect when the allocator returns a null pointer.
// Constructor shall not be called in this case.
}
break;
}
case ConstructionContext::SimpleReturnedValueKind:
case ConstructionContext::CXX17ElidedCopyReturnedValueKind: {
// The temporary is to be managed by the parent stack frame.
// So build it in the parent stack frame if we're not in the
// top frame of the analysis.
const StackFrameContext *SFC = LCtx->getStackFrame();
if (const LocationContext *CallerLCtx = SFC->getParent()) {
auto RTC = (*SFC->getCallSiteBlock())[SFC->getIndex()]
.getAs<CFGCXXRecordTypedCall>();
if (!RTC) {
// We were unable to find the correct construction context for the
// call in the parent stack frame. This is equivalent to not being
// able to find construction context at all.
break;
}
if (isa<BlockInvocationContext>(CallerLCtx)) {
// Unwrap block invocation contexts. They're mostly part of
// the current stack frame.
CallerLCtx = CallerLCtx->getParent();
assert(!isa<BlockInvocationContext>(CallerLCtx));
}
return handleConstructionContext(
cast<Expr>(SFC->getCallSite()), State, CallerLCtx,
RTC->getConstructionContext(), CallOpts);
} else {
// We are on the top frame of the analysis. We do not know where is the
// object returned to. Conjure a symbolic region for the return value.
// TODO: We probably need a new MemRegion kind to represent the storage
// of that SymbolicRegion, so that we cound produce a fancy symbol
// instead of an anonymous conjured symbol.
// TODO: Do we need to track the region to avoid having it dead
// too early? It does die too early, at least in C++17, but because
// putting anything into a SymbolicRegion causes an immediate escape,
// it doesn't cause any leak false positives.
const auto *RCC = cast<ReturnedValueConstructionContext>(CC);
// Make sure that this doesn't coincide with any other symbol
// conjured for the returned expression.
static const int TopLevelSymRegionTag = 0;
const Expr *RetE = RCC->getReturnStmt()->getRetValue();
assert(RetE && "Void returns should not have a construction context");
QualType ReturnTy = RetE->getType();
QualType RegionTy = ACtx.getPointerType(ReturnTy);
SVal V = SVB.conjureSymbolVal(&TopLevelSymRegionTag, RetE, SFC,
RegionTy, currBldrCtx->blockCount());
return std::make_pair(State, V);
}
llvm_unreachable("Unhandled return value construction context!");
}
case ConstructionContext::ElidedTemporaryObjectKind: {
assert(AMgr.getAnalyzerOptions().ShouldElideConstructors);
const auto *TCC = cast<ElidedTemporaryObjectConstructionContext>(CC);
const CXXBindTemporaryExpr *BTE = TCC->getCXXBindTemporaryExpr();
const MaterializeTemporaryExpr *MTE = TCC->getMaterializedTemporaryExpr();
const CXXConstructExpr *CE = TCC->getConstructorAfterElision();
// Support pre-C++17 copy elision. We'll have the elidable copy
// constructor in the AST and in the CFG, but we'll skip it
// and construct directly into the final object. This call
// also sets the CallOpts flags for us.
SVal V;
// If the elided copy/move constructor is not supported, there's still
// benefit in trying to model the non-elided constructor.
// Stash our state before trying to elide, as it'll get overwritten.
ProgramStateRef PreElideState = State;
EvalCallOptions PreElideCallOpts = CallOpts;
std::tie(State, V) = handleConstructionContext(
CE, State, LCtx, TCC->getConstructionContextAfterElision(), CallOpts);
// FIXME: This definition of "copy elision has not failed" is unreliable.
// It doesn't indicate that the constructor will actually be inlined
// later; it is still up to evalCall() to decide.
if (!CallOpts.IsCtorOrDtorWithImproperlyModeledTargetRegion) {
// Remember that we've elided the constructor.
State = addObjectUnderConstruction(State, CE, LCtx, V);
// Remember that we've elided the destructor.
if (BTE)
State = elideDestructor(State, BTE, LCtx);
// Instead of materialization, shamelessly return
// the final object destination.
if (MTE)
State = addObjectUnderConstruction(State, MTE, LCtx, V);
return std::make_pair(State, V);
} else {
// Copy elision failed. Revert the changes and proceed as if we have
// a simple temporary.
State = PreElideState;
CallOpts = PreElideCallOpts;
}
LLVM_FALLTHROUGH;
}
case ConstructionContext::SimpleTemporaryObjectKind: {
const auto *TCC = cast<TemporaryObjectConstructionContext>(CC);
const CXXBindTemporaryExpr *BTE = TCC->getCXXBindTemporaryExpr();
const MaterializeTemporaryExpr *MTE = TCC->getMaterializedTemporaryExpr();
SVal V = UnknownVal();
if (MTE) {
if (const ValueDecl *VD = MTE->getExtendingDecl()) {
assert(MTE->getStorageDuration() != SD_FullExpression);
if (!VD->getType()->isReferenceType()) {
// We're lifetime-extended by a surrounding aggregate.
// Automatic destructors aren't quite working in this case
// on the CFG side. We should warn the caller about that.
// FIXME: Is there a better way to retrieve this information from
// the MaterializeTemporaryExpr?
CallOpts.IsTemporaryLifetimeExtendedViaAggregate = true;
}
}
if (MTE->getStorageDuration() == SD_Static ||
MTE->getStorageDuration() == SD_Thread)
V = loc::MemRegionVal(MRMgr.getCXXStaticTempObjectRegion(E));
}
if (V.isUnknown())
V = loc::MemRegionVal(MRMgr.getCXXTempObjectRegion(E, LCtx));
if (BTE)
State = addObjectUnderConstruction(State, BTE, LCtx, V);
if (MTE)
State = addObjectUnderConstruction(State, MTE, LCtx, V);
CallOpts.IsTemporaryCtorOrDtor = true;
return std::make_pair(State, V);
}
case ConstructionContext::ArgumentKind: {
// Arguments are technically temporaries.
CallOpts.IsTemporaryCtorOrDtor = true;
const auto *ACC = cast<ArgumentConstructionContext>(CC);
const Expr *E = ACC->getCallLikeExpr();
unsigned Idx = ACC->getIndex();
const CXXBindTemporaryExpr *BTE = ACC->getCXXBindTemporaryExpr();
CallEventManager &CEMgr = getStateManager().getCallEventManager();
SVal V = UnknownVal();
auto getArgLoc = [&](CallEventRef<> Caller) -> Optional<SVal> {
const LocationContext *FutureSFC =
Caller->getCalleeStackFrame(currBldrCtx->blockCount());
// Return early if we are unable to reliably foresee
// the future stack frame.
if (!FutureSFC)
return None;
// This should be equivalent to Caller->getDecl() for now, but
// FutureSFC->getDecl() is likely to support better stuff (like
// virtual functions) earlier.
const Decl *CalleeD = FutureSFC->getDecl();
// FIXME: Support for variadic arguments is not implemented here yet.
if (CallEvent::isVariadic(CalleeD))
return None;
// Operator arguments do not correspond to operator parameters
// because this-argument is implemented as a normal argument in
// operator call expressions but not in operator declarations.
const VarRegion *VR = Caller->getParameterLocation(
*Caller->getAdjustedParameterIndex(Idx), currBldrCtx->blockCount());
if (!VR)
return None;
return loc::MemRegionVal(VR);
};
if (const auto *CE = dyn_cast<CallExpr>(E)) {
CallEventRef<> Caller = CEMgr.getSimpleCall(CE, State, LCtx);
if (auto OptV = getArgLoc(Caller))
V = *OptV;
else
break;
State = addObjectUnderConstruction(State, {CE, Idx}, LCtx, V);
} else if (const auto *CCE = dyn_cast<CXXConstructExpr>(E)) {
// Don't bother figuring out the target region for the future
// constructor because we won't need it.
CallEventRef<> Caller =
CEMgr.getCXXConstructorCall(CCE, /*Target=*/nullptr, State, LCtx);
if (auto OptV = getArgLoc(Caller))
V = *OptV;
else
break;
State = addObjectUnderConstruction(State, {CCE, Idx}, LCtx, V);
} else if (const auto *ME = dyn_cast<ObjCMessageExpr>(E)) {
CallEventRef<> Caller = CEMgr.getObjCMethodCall(ME, State, LCtx);
if (auto OptV = getArgLoc(Caller))
V = *OptV;
else
break;
State = addObjectUnderConstruction(State, {ME, Idx}, LCtx, V);
}
assert(!V.isUnknown());
if (BTE)
State = addObjectUnderConstruction(State, BTE, LCtx, V);
return std::make_pair(State, V);
}
}
}
// If we couldn't find an existing region to construct into, assume we're
// constructing a temporary. Notify the caller of our failure.
CallOpts.IsCtorOrDtorWithImproperlyModeledTargetRegion = true;
return std::make_pair(
State, loc::MemRegionVal(MRMgr.getCXXTempObjectRegion(E, LCtx)));
}
void ExprEngine::handleConstructor(const Expr *E,
ExplodedNode *Pred,
ExplodedNodeSet &destNodes) {
const auto *CE = dyn_cast<CXXConstructExpr>(E);
const auto *CIE = dyn_cast<CXXInheritedCtorInitExpr>(E);
assert(CE || CIE);
const LocationContext *LCtx = Pred->getLocationContext();
ProgramStateRef State = Pred->getState();
SVal Target = UnknownVal();
if (CE) {
if (Optional<SVal> ElidedTarget =
getObjectUnderConstruction(State, CE, LCtx)) {
// We've previously modeled an elidable constructor by pretending that it
// in fact constructs into the correct target. This constructor can
// therefore be skipped.
Target = *ElidedTarget;
StmtNodeBuilder Bldr(Pred, destNodes, *currBldrCtx);
State = finishObjectConstruction(State, CE, LCtx);
if (auto L = Target.getAs<Loc>())
State = State->BindExpr(CE, LCtx, State->getSVal(*L, CE->getType()));
Bldr.generateNode(CE, Pred, State);
return;
}
}
// FIXME: Handle arrays, which run the same constructor for every element.
// For now, we just run the first constructor (which should still invalidate
// the entire array).
EvalCallOptions CallOpts;
auto C = getCurrentCFGElement().getAs<CFGConstructor>();
assert(C || getCurrentCFGElement().getAs<CFGStmt>());
const ConstructionContext *CC = C ? C->getConstructionContext() : nullptr;
const CXXConstructExpr::ConstructionKind CK =
CE ? CE->getConstructionKind() : CIE->getConstructionKind();
switch (CK) {
case CXXConstructExpr::CK_Complete: {
// Inherited constructors are always base class constructors.
assert(CE && !CIE && "A complete constructor is inherited?!");
// The target region is found from construction context.
std::tie(State, Target) =
handleConstructionContext(CE, State, LCtx, CC, CallOpts);
break;
}
case CXXConstructExpr::CK_VirtualBase: {
// Make sure we are not calling virtual base class initializers twice.
// Only the most-derived object should initialize virtual base classes.
const auto *OuterCtor = dyn_cast_or_null<CXXConstructExpr>(
LCtx->getStackFrame()->getCallSite());
assert(
(!OuterCtor ||
OuterCtor->getConstructionKind() == CXXConstructExpr::CK_Complete ||
OuterCtor->getConstructionKind() == CXXConstructExpr::CK_Delegating) &&
("This virtual base should have already been initialized by "
"the most derived class!"));
(void)OuterCtor;
LLVM_FALLTHROUGH;
}
case CXXConstructExpr::CK_NonVirtualBase:
// In C++17, classes with non-virtual bases may be aggregates, so they would
// be initialized as aggregates without a constructor call, so we may have
// a base class constructed directly into an initializer list without
// having the derived-class constructor call on the previous stack frame.
// Initializer lists may be nested into more initializer lists that
// correspond to surrounding aggregate initializations.
// FIXME: For now this code essentially bails out. We need to find the
// correct target region and set it.
// FIXME: Instead of relying on the ParentMap, we should have the
// trigger-statement (InitListExpr in this case) passed down from CFG or
// otherwise always available during construction.
if (dyn_cast_or_null<InitListExpr>(LCtx->getParentMap().getParent(E))) {
MemRegionManager &MRMgr = getSValBuilder().getRegionManager();
Target = loc::MemRegionVal(MRMgr.getCXXTempObjectRegion(E, LCtx));
CallOpts.IsCtorOrDtorWithImproperlyModeledTargetRegion = true;
break;
}
LLVM_FALLTHROUGH;
case CXXConstructExpr::CK_Delegating: {
const CXXMethodDecl *CurCtor = cast<CXXMethodDecl>(LCtx->getDecl());
Loc ThisPtr = getSValBuilder().getCXXThis(CurCtor,
LCtx->getStackFrame());
SVal ThisVal = State->getSVal(ThisPtr);
if (CK == CXXConstructExpr::CK_Delegating) {
Target = ThisVal;
} else {
// Cast to the base type.
bool IsVirtual = (CK == CXXConstructExpr::CK_VirtualBase);
SVal BaseVal =
getStoreManager().evalDerivedToBase(ThisVal, E->getType(), IsVirtual);
Target = BaseVal;
}
break;
}
}
if (State != Pred->getState()) {
static SimpleProgramPointTag T("ExprEngine",
"Prepare for object construction");
ExplodedNodeSet DstPrepare;
StmtNodeBuilder BldrPrepare(Pred, DstPrepare, *currBldrCtx);
BldrPrepare.generateNode(E, Pred, State, &T, ProgramPoint::PreStmtKind);
assert(DstPrepare.size() <= 1);
if (DstPrepare.size() == 0)
return;
Pred = *BldrPrepare.begin();
}
const MemRegion *TargetRegion = Target.getAsRegion();
CallEventManager &CEMgr = getStateManager().getCallEventManager();
CallEventRef<> Call =
CIE ? (CallEventRef<>)CEMgr.getCXXInheritedConstructorCall(
CIE, TargetRegion, State, LCtx)
: (CallEventRef<>)CEMgr.getCXXConstructorCall(
CE, TargetRegion, State, LCtx);
ExplodedNodeSet DstPreVisit;
getCheckerManager().runCheckersForPreStmt(DstPreVisit, Pred, E, *this);
ExplodedNodeSet PreInitialized;
if (CE) {
// FIXME: Is it possible and/or useful to do this before PreStmt?
StmtNodeBuilder Bldr(DstPreVisit, PreInitialized, *currBldrCtx);
for (ExplodedNodeSet::iterator I = DstPreVisit.begin(),
E = DstPreVisit.end();
I != E; ++I) {
ProgramStateRef State = (*I)->getState();
if (CE->requiresZeroInitialization()) {
// FIXME: Once we properly handle constructors in new-expressions, we'll
// need to invalidate the region before setting a default value, to make
// sure there aren't any lingering bindings around. This probably needs
// to happen regardless of whether or not the object is zero-initialized
// to handle random fields of a placement-initialized object picking up
// old bindings. We might only want to do it when we need to, though.
// FIXME: This isn't actually correct for arrays -- we need to zero-
// initialize the entire array, not just the first element -- but our
// handling of arrays everywhere else is weak as well, so this shouldn't
// actually make things worse. Placement new makes this tricky as well,
// since it's then possible to be initializing one part of a multi-
// dimensional array.
State = State->bindDefaultZero(Target, LCtx);
}
Bldr.generateNode(CE, *I, State, /*tag=*/nullptr,
ProgramPoint::PreStmtKind);
}
} else {
PreInitialized = DstPreVisit;
}
ExplodedNodeSet DstPreCall;
getCheckerManager().runCheckersForPreCall(DstPreCall, PreInitialized,
*Call, *this);
ExplodedNodeSet DstEvaluated;
StmtNodeBuilder Bldr(DstPreCall, DstEvaluated, *currBldrCtx);
if (CE && CE->getConstructor()->isTrivial() &&
CE->getConstructor()->isCopyOrMoveConstructor() &&
!CallOpts.IsArrayCtorOrDtor) {
// FIXME: Handle other kinds of trivial constructors as well.
for (ExplodedNodeSet::iterator I = DstPreCall.begin(), E = DstPreCall.end();
I != E; ++I)
performTrivialCopy(Bldr, *I, *Call);
} else {
for (ExplodedNodeSet::iterator I = DstPreCall.begin(), E = DstPreCall.end();
I != E; ++I)
defaultEvalCall(Bldr, *I, *Call, CallOpts);
}
// If the CFG was constructed without elements for temporary destructors
// and the just-called constructor created a temporary object then
// stop exploration if the temporary object has a noreturn constructor.
// This can lose coverage because the destructor, if it were present
// in the CFG, would be called at the end of the full expression or
// later (for life-time extended temporaries) -- but avoids infeasible
// paths when no-return temporary destructors are used for assertions.
const AnalysisDeclContext *ADC = LCtx->getAnalysisDeclContext();
if (!ADC->getCFGBuildOptions().AddTemporaryDtors) {
if (TargetRegion && isa<CXXTempObjectRegion>(TargetRegion) &&
cast<CXXConstructorDecl>(Call->getDecl())
->getParent()->isAnyDestructorNoReturn()) {
// If we've inlined the constructor, then DstEvaluated would be empty.
// In this case we still want a sink, which could be implemented
// in processCallExit. But we don't have that implemented at the moment,
// so if you hit this assertion, see if you can avoid inlining
// the respective constructor when analyzer-config cfg-temporary-dtors
// is set to false.
// Otherwise there's nothing wrong with inlining such constructor.
assert(!DstEvaluated.empty() &&
"We should not have inlined this constructor!");
for (ExplodedNode *N : DstEvaluated) {
Bldr.generateSink(E, N, N->getState());
}
// There is no need to run the PostCall and PostStmt checker
// callbacks because we just generated sinks on all nodes in th
// frontier.
return;
}
}
ExplodedNodeSet DstPostArgumentCleanup;
for (auto I : DstEvaluated)
finishArgumentConstruction(DstPostArgumentCleanup, I, *Call);
// If there were other constructors called for object-type arguments
// of this constructor, clean them up.
ExplodedNodeSet DstPostCall;
getCheckerManager().runCheckersForPostCall(DstPostCall,
DstPostArgumentCleanup,
*Call, *this);
getCheckerManager().runCheckersForPostStmt(destNodes, DstPostCall, E, *this);
}
void ExprEngine::VisitCXXConstructExpr(const CXXConstructExpr *CE,
ExplodedNode *Pred,
ExplodedNodeSet &Dst) {
handleConstructor(CE, Pred, Dst);
}
void ExprEngine::VisitCXXInheritedCtorInitExpr(
const CXXInheritedCtorInitExpr *CE, ExplodedNode *Pred,
ExplodedNodeSet &Dst) {
handleConstructor(CE, Pred, Dst);
}
void ExprEngine::VisitCXXDestructor(QualType ObjectType,
const MemRegion *Dest,
const Stmt *S,
bool IsBaseDtor,
ExplodedNode *Pred,
ExplodedNodeSet &Dst,
EvalCallOptions &CallOpts) {
assert(S && "A destructor without a trigger!");
const LocationContext *LCtx = Pred->getLocationContext();
ProgramStateRef State = Pred->getState();
const CXXRecordDecl *RecordDecl = ObjectType->getAsCXXRecordDecl();
assert(RecordDecl && "Only CXXRecordDecls should have destructors");
const CXXDestructorDecl *DtorDecl = RecordDecl->getDestructor();
// FIXME: There should always be a Decl, otherwise the destructor call
// shouldn't have been added to the CFG in the first place.
if (!DtorDecl) {
// Skip the invalid destructor. We cannot simply return because
// it would interrupt the analysis instead.
static SimpleProgramPointTag T("ExprEngine", "SkipInvalidDestructor");
// FIXME: PostImplicitCall with a null decl may crash elsewhere anyway.
PostImplicitCall PP(/*Decl=*/nullptr, S->getEndLoc(), LCtx, &T);
NodeBuilder Bldr(Pred, Dst, *currBldrCtx);
Bldr.generateNode(PP, Pred->getState(), Pred);
return;
}
if (!Dest) {
// We're trying to destroy something that is not a region. This may happen
// for a variety of reasons (unknown target region, concrete integer instead
// of target region, etc.). The current code makes an attempt to recover.
// FIXME: We probably don't really need to recover when we're dealing
// with concrete integers specifically.
CallOpts.IsCtorOrDtorWithImproperlyModeledTargetRegion = true;
if (const Expr *E = dyn_cast_or_null<Expr>(S)) {
Dest = MRMgr.getCXXTempObjectRegion(E, Pred->getLocationContext());
} else {
static SimpleProgramPointTag T("ExprEngine", "SkipInvalidDestructor");
NodeBuilder Bldr(Pred, Dst, *currBldrCtx);
Bldr.generateSink(Pred->getLocation().withTag(&T),
Pred->getState(), Pred);
return;
}
}
CallEventManager &CEMgr = getStateManager().getCallEventManager();
CallEventRef<CXXDestructorCall> Call =
CEMgr.getCXXDestructorCall(DtorDecl, S, Dest, IsBaseDtor, State, LCtx);
PrettyStackTraceLoc CrashInfo(getContext().getSourceManager(),
Call->getSourceRange().getBegin(),
"Error evaluating destructor");
ExplodedNodeSet DstPreCall;
getCheckerManager().runCheckersForPreCall(DstPreCall, Pred,
*Call, *this);
ExplodedNodeSet DstInvalidated;
StmtNodeBuilder Bldr(DstPreCall, DstInvalidated, *currBldrCtx);
for (ExplodedNodeSet::iterator I = DstPreCall.begin(), E = DstPreCall.end();
I != E; ++I)
defaultEvalCall(Bldr, *I, *Call, CallOpts);
getCheckerManager().runCheckersForPostCall(Dst, DstInvalidated,
*Call, *this);
}
void ExprEngine::VisitCXXNewAllocatorCall(const CXXNewExpr *CNE,
ExplodedNode *Pred,
ExplodedNodeSet &Dst) {
ProgramStateRef State = Pred->getState();
const LocationContext *LCtx = Pred->getLocationContext();
PrettyStackTraceLoc CrashInfo(getContext().getSourceManager(),
CNE->getBeginLoc(),
"Error evaluating New Allocator Call");
CallEventManager &CEMgr = getStateManager().getCallEventManager();
CallEventRef<CXXAllocatorCall> Call =
CEMgr.getCXXAllocatorCall(CNE, State, LCtx);
ExplodedNodeSet DstPreCall;
getCheckerManager().runCheckersForPreCall(DstPreCall, Pred,
*Call, *this);
ExplodedNodeSet DstPostCall;
StmtNodeBuilder CallBldr(DstPreCall, DstPostCall, *currBldrCtx);
for (auto I : DstPreCall) {
// FIXME: Provide evalCall for checkers?
defaultEvalCall(CallBldr, I, *Call);
}
// If the call is inlined, DstPostCall will be empty and we bail out now.
// Store return value of operator new() for future use, until the actual
// CXXNewExpr gets processed.
ExplodedNodeSet DstPostValue;
StmtNodeBuilder ValueBldr(DstPostCall, DstPostValue, *currBldrCtx);
for (auto I : DstPostCall) {
// FIXME: Because CNE serves as the "call site" for the allocator (due to
// lack of a better expression in the AST), the conjured return value symbol
// is going to be of the same type (C++ object pointer type). Technically
// this is not correct because the operator new's prototype always says that
// it returns a 'void *'. So we should change the type of the symbol,
// and then evaluate the cast over the symbolic pointer from 'void *' to
// the object pointer type. But without changing the symbol's type it
// is breaking too much to evaluate the no-op symbolic cast over it, so we
// skip it for now.
ProgramStateRef State = I->getState();
SVal RetVal = State->getSVal(CNE, LCtx);
// If this allocation function is not declared as non-throwing, failures
// /must/ be signalled by exceptions, and thus the return value will never
// be NULL. -fno-exceptions does not influence this semantics.
// FIXME: GCC has a -fcheck-new option, which forces it to consider the case
// where new can return NULL. If we end up supporting that option, we can
// consider adding a check for it here.
// C++11 [basic.stc.dynamic.allocation]p3.
if (const FunctionDecl *FD = CNE->getOperatorNew()) {
QualType Ty = FD->getType();
if (const auto *ProtoType = Ty->getAs<FunctionProtoType>())
if (!ProtoType->isNothrow())
State = State->assume(RetVal.castAs<DefinedOrUnknownSVal>(), true);
}
ValueBldr.generateNode(
CNE, I, addObjectUnderConstruction(State, CNE, LCtx, RetVal));
}
ExplodedNodeSet DstPostPostCallCallback;
getCheckerManager().runCheckersForPostCall(DstPostPostCallCallback,
DstPostValue, *Call, *this);
for (auto I : DstPostPostCallCallback) {
getCheckerManager().runCheckersForNewAllocator(
CNE, *getObjectUnderConstruction(I->getState(), CNE, LCtx), Dst, I,
*this);
}
}
void ExprEngine::VisitCXXNewExpr(const CXXNewExpr *CNE, ExplodedNode *Pred,
ExplodedNodeSet &Dst) {
// FIXME: Much of this should eventually migrate to CXXAllocatorCall.
// Also, we need to decide how allocators actually work -- they're not
// really part of the CXXNewExpr because they happen BEFORE the
// CXXConstructExpr subexpression. See PR12014 for some discussion.
unsigned blockCount = currBldrCtx->blockCount();
const LocationContext *LCtx = Pred->getLocationContext();
SVal symVal = UnknownVal();
FunctionDecl *FD = CNE->getOperatorNew();
bool IsStandardGlobalOpNewFunction =
FD->isReplaceableGlobalAllocationFunction();
ProgramStateRef State = Pred->getState();
// Retrieve the stored operator new() return value.
if (AMgr.getAnalyzerOptions().MayInlineCXXAllocator) {
symVal = *getObjectUnderConstruction(State, CNE, LCtx);
State = finishObjectConstruction(State, CNE, LCtx);
}
// We assume all standard global 'operator new' functions allocate memory in
// heap. We realize this is an approximation that might not correctly model
// a custom global allocator.
if (symVal.isUnknown()) {
if (IsStandardGlobalOpNewFunction)
symVal = svalBuilder.getConjuredHeapSymbolVal(CNE, LCtx, blockCount);
else
symVal = svalBuilder.conjureSymbolVal(nullptr, CNE, LCtx, CNE->getType(),
blockCount);
}
CallEventManager &CEMgr = getStateManager().getCallEventManager();
CallEventRef<CXXAllocatorCall> Call =
CEMgr.getCXXAllocatorCall(CNE, State, LCtx);
if (!AMgr.getAnalyzerOptions().MayInlineCXXAllocator) {
// Invalidate placement args.
// FIXME: Once we figure out how we want allocators to work,
// we should be using the usual pre-/(default-)eval-/post-call checkers
// here.
State = Call->invalidateRegions(blockCount);
if (!State)
return;
// If this allocation function is not declared as non-throwing, failures
// /must/ be signalled by exceptions, and thus the return value will never
// be NULL. -fno-exceptions does not influence this semantics.
// FIXME: GCC has a -fcheck-new option, which forces it to consider the case
// where new can return NULL. If we end up supporting that option, we can
// consider adding a check for it here.
// C++11 [basic.stc.dynamic.allocation]p3.
if (FD) {
QualType Ty = FD->getType();
if (const auto *ProtoType = Ty->getAs<FunctionProtoType>())
if (!ProtoType->isNothrow())
if (auto dSymVal = symVal.getAs<DefinedOrUnknownSVal>())
State = State->assume(*dSymVal, true);
}
}
StmtNodeBuilder Bldr(Pred, Dst, *currBldrCtx);
SVal Result = symVal;
if (CNE->isArray()) {
// FIXME: allocating an array requires simulating the constructors.
// For now, just return a symbolicated region.
if (const auto *NewReg = cast_or_null<SubRegion>(symVal.getAsRegion())) {
QualType ObjTy = CNE->getType()->getPointeeType();
const ElementRegion *EleReg =
getStoreManager().GetElementZeroRegion(NewReg, ObjTy);
Result = loc::MemRegionVal(EleReg);
}
State = State->BindExpr(CNE, Pred->getLocationContext(), Result);
Bldr.generateNode(CNE, Pred, State);
return;
}
// FIXME: Once we have proper support for CXXConstructExprs inside
// CXXNewExpr, we need to make sure that the constructed object is not
// immediately invalidated here. (The placement call should happen before
// the constructor call anyway.)
if (FD && FD->isReservedGlobalPlacementOperator()) {
// Non-array placement new should always return the placement location.
SVal PlacementLoc = State->getSVal(CNE->getPlacementArg(0), LCtx);
Result = svalBuilder.evalCast(PlacementLoc, CNE->getType(),
CNE->getPlacementArg(0)->getType());
}
// Bind the address of the object, then check to see if we cached out.
State = State->BindExpr(CNE, LCtx, Result);
ExplodedNode *NewN = Bldr.generateNode(CNE, Pred, State);
if (!NewN)
return;
// If the type is not a record, we won't have a CXXConstructExpr as an
// initializer. Copy the value over.
if (const Expr *Init = CNE->getInitializer()) {
if (!isa<CXXConstructExpr>(Init)) {
assert(Bldr.getResults().size() == 1);
Bldr.takeNodes(NewN);
evalBind(Dst, CNE, NewN, Result, State->getSVal(Init, LCtx),
/*FirstInit=*/IsStandardGlobalOpNewFunction);
}
}
}
void ExprEngine::VisitCXXDeleteExpr(const CXXDeleteExpr *CDE,
ExplodedNode *Pred, ExplodedNodeSet &Dst) {
StmtNodeBuilder Bldr(Pred, Dst, *currBldrCtx);
ProgramStateRef state = Pred->getState();
Bldr.generateNode(CDE, Pred, state);
}
void ExprEngine::VisitCXXCatchStmt(const CXXCatchStmt *CS,
ExplodedNode *Pred,
ExplodedNodeSet &Dst) {
const VarDecl *VD = CS->getExceptionDecl();
if (!VD) {
Dst.Add(Pred);
return;
}
const LocationContext *LCtx = Pred->getLocationContext();
SVal V = svalBuilder.conjureSymbolVal(CS, LCtx, VD->getType(),
currBldrCtx->blockCount());
ProgramStateRef state = Pred->getState();
state = state->bindLoc(state->getLValue(VD, LCtx), V, LCtx);
StmtNodeBuilder Bldr(Pred, Dst, *currBldrCtx);
Bldr.generateNode(CS, Pred, state);
}
void ExprEngine::VisitCXXThisExpr(const CXXThisExpr *TE, ExplodedNode *Pred,
ExplodedNodeSet &Dst) {
StmtNodeBuilder Bldr(Pred, Dst, *currBldrCtx);
// Get the this object region from StoreManager.
const LocationContext *LCtx = Pred->getLocationContext();
const MemRegion *R =
svalBuilder.getRegionManager().getCXXThisRegion(
getContext().getCanonicalType(TE->getType()),
LCtx);
ProgramStateRef state = Pred->getState();
SVal V = state->getSVal(loc::MemRegionVal(R));
Bldr.generateNode(TE, Pred, state->BindExpr(TE, LCtx, V));
}
void ExprEngine::VisitLambdaExpr(const LambdaExpr *LE, ExplodedNode *Pred,
ExplodedNodeSet &Dst) {
const LocationContext *LocCtxt = Pred->getLocationContext();
// Get the region of the lambda itself.
const MemRegion *R = svalBuilder.getRegionManager().getCXXTempObjectRegion(
LE, LocCtxt);
SVal V = loc::MemRegionVal(R);
ProgramStateRef State = Pred->getState();
// If we created a new MemRegion for the lambda, we should explicitly bind
// the captures.
CXXRecordDecl::field_iterator CurField = LE->getLambdaClass()->field_begin();
for (LambdaExpr::const_capture_init_iterator i = LE->capture_init_begin(),
e = LE->capture_init_end();
i != e; ++i, ++CurField) {
FieldDecl *FieldForCapture = *CurField;
SVal FieldLoc = State->getLValue(FieldForCapture, V);
SVal InitVal;
if (!FieldForCapture->hasCapturedVLAType()) {
Expr *InitExpr = *i;
assert(InitExpr && "Capture missing initialization expression");
InitVal = State->getSVal(InitExpr, LocCtxt);
} else {
// The field stores the length of a captured variable-length array.
// These captures don't have initialization expressions; instead we
// get the length from the VLAType size expression.
Expr *SizeExpr = FieldForCapture->getCapturedVLAType()->getSizeExpr();
InitVal = State->getSVal(SizeExpr, LocCtxt);
}
State = State->bindLoc(FieldLoc, InitVal, LocCtxt);
}
// Decay the Loc into an RValue, because there might be a
// MaterializeTemporaryExpr node above this one which expects the bound value
// to be an RValue.
SVal LambdaRVal = State->getSVal(R);
ExplodedNodeSet Tmp;
StmtNodeBuilder Bldr(Pred, Tmp, *currBldrCtx);
// FIXME: is this the right program point kind?
Bldr.generateNode(LE, Pred,
State->BindExpr(LE, LocCtxt, LambdaRVal),
nullptr, ProgramPoint::PostLValueKind);
// FIXME: Move all post/pre visits to ::Visit().
getCheckerManager().runCheckersForPostStmt(Dst, Tmp, LE, *this);
}
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