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//===- ExprEngineCXX.cpp - ExprEngine support for C++ -----------*- 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 the C++ expression evaluation engine.
//
//===----------------------------------------------------------------------===//
#include "clang/StaticAnalyzer/Core/PathSensitive/ExprEngine.h"
#include "clang/AST/DeclCXX.h"
#include "clang/AST/StmtCXX.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->GetTemporaryExpr()->IgnoreParens();
ProgramStateRef state = Pred->getState();
const LocationContext *LCtx = Pred->getLocationContext();
SVal V = state->getSVal(tempExpr, LCtx);
// If the value is already a CXXTempObjectRegion, it is fine as it is.
// Otherwise, create a new CXXTempObjectRegion, and copy the value into it.
// This is an optimization for when an rvalue is constructed and then
// immediately materialized.
const MemRegion *MR = V.getAsRegion();
if (const CXXTempObjectRegion *TR =
dyn_cast_or_null<CXXTempObjectRegion>(MR)) {
if (getContext().hasSameUnqualifiedType(TR->getValueType(), ME->getType()))
state = state->BindExpr(ME, LCtx, V);
}
if (state == Pred->getState())
state = createTemporaryRegionIfNeeded(state, LCtx, tempExpr, ME);
Bldr.generateNode(ME, Pred, state);
}
void ExprEngine::performTrivialCopy(NodeBuilder &Bldr, ExplodedNode *Pred,
const CXXConstructorCall &Call) {
const CXXConstructExpr *CtorExpr = Call.getOriginExpr();
assert(CtorExpr->getConstructor()->isCopyOrMoveConstructor());
assert(CtorExpr->getConstructor()->isTrivial());
SVal ThisVal = Call.getCXXThisVal();
const LocationContext *LCtx = Pred->getLocationContext();
ExplodedNodeSet Dst;
Bldr.takeNodes(Pred);
SVal V = Call.getArgSVal(0);
// Make sure the value being copied is not unknown.
if (Optional<Loc> L = V.getAs<Loc>())
V = Pred->getState()->getSVal(*L);
evalBind(Dst, CtorExpr, Pred, ThisVal, V, true);
PostStmt PS(CtorExpr, LCtx);
for (ExplodedNodeSet::iterator I = Dst.begin(), E = Dst.end();
I != E; ++I) {
ProgramStateRef State = (*I)->getState();
State = bindReturnValue(Call, LCtx, State);
Bldr.generateNode(PS, State, *I);
}
}
void ExprEngine::VisitCXXConstructExpr(const CXXConstructExpr *CE,
ExplodedNode *Pred,
ExplodedNodeSet &destNodes) {
const LocationContext *LCtx = Pred->getLocationContext();
ProgramStateRef State = Pred->getState();
const MemRegion *Target = 0;
bool IsArray = false;
switch (CE->getConstructionKind()) {
case CXXConstructExpr::CK_Complete: {
// See if we're constructing an existing region by looking at the next
// element in the CFG.
const CFGBlock *B = currBldrCtx->getBlock();
if (currStmtIdx + 1 < B->size()) {
CFGElement Next = (*B)[currStmtIdx+1];
// Is this a constructor for a local variable?
if (Optional<CFGStmt> StmtElem = Next.getAs<CFGStmt>()) {
if (const DeclStmt *DS = dyn_cast<DeclStmt>(StmtElem->getStmt())) {
if (const VarDecl *Var = dyn_cast<VarDecl>(DS->getSingleDecl())) {
if (Var->getInit()->IgnoreImplicit() == CE) {
QualType Ty = Var->getType();
if (const ArrayType *AT = getContext().getAsArrayType(Ty)) {
// FIXME: Handle arrays, which run the same constructor for
// every element. This workaround will just run the first
// constructor (which should still invalidate the entire array).
SVal Base = State->getLValue(Var, LCtx);
Target = State->getLValue(AT->getElementType(),
getSValBuilder().makeZeroArrayIndex(),
Base).getAsRegion();
IsArray = true;
} else {
Target = State->getLValue(Var, LCtx).getAsRegion();
}
}
}
}
}
// Is this a constructor for a member?
if (Optional<CFGInitializer> InitElem = Next.getAs<CFGInitializer>()) {
const CXXCtorInitializer *Init = InitElem->getInitializer();
assert(Init->isAnyMemberInitializer());
const CXXMethodDecl *CurCtor = cast<CXXMethodDecl>(LCtx->getDecl());
Loc ThisPtr = getSValBuilder().getCXXThis(CurCtor,
LCtx->getCurrentStackFrame());
SVal ThisVal = State->getSVal(ThisPtr);
if (Init->isIndirectMemberInitializer()) {
SVal Field = State->getLValue(Init->getIndirectMember(), ThisVal);
Target = Field.getAsRegion();
} else {
SVal Field = State->getLValue(Init->getMember(), ThisVal);
Target = Field.getAsRegion();
}
}
// FIXME: This will eventually need to handle new-expressions as well.
}
// If we couldn't find an existing region to construct into, assume we're
// constructing a temporary.
if (!Target) {
MemRegionManager &MRMgr = getSValBuilder().getRegionManager();
Target = MRMgr.getCXXTempObjectRegion(CE, LCtx);
}
break;
}
case CXXConstructExpr::CK_NonVirtualBase:
case CXXConstructExpr::CK_VirtualBase:
case CXXConstructExpr::CK_Delegating: {
const CXXMethodDecl *CurCtor = cast<CXXMethodDecl>(LCtx->getDecl());
Loc ThisPtr = getSValBuilder().getCXXThis(CurCtor,
LCtx->getCurrentStackFrame());
SVal ThisVal = State->getSVal(ThisPtr);
if (CE->getConstructionKind() == CXXConstructExpr::CK_Delegating) {
Target = ThisVal.getAsRegion();
} else {
// Cast to the base type.
bool IsVirtual =
(CE->getConstructionKind() == CXXConstructExpr::CK_VirtualBase);
SVal BaseVal = getStoreManager().evalDerivedToBase(ThisVal, CE->getType(),
IsVirtual);
Target = BaseVal.getAsRegion();
}
break;
}
}
CallEventManager &CEMgr = getStateManager().getCallEventManager();
CallEventRef<CXXConstructorCall> Call =
CEMgr.getCXXConstructorCall(CE, Target, State, LCtx);
ExplodedNodeSet DstPreVisit;
getCheckerManager().runCheckersForPreStmt(DstPreVisit, Pred, CE, *this);
ExplodedNodeSet DstPreCall;
getCheckerManager().runCheckersForPreCall(DstPreCall, DstPreVisit,
*Call, *this);
ExplodedNodeSet DstEvaluated;
StmtNodeBuilder Bldr(DstPreCall, DstEvaluated, *currBldrCtx);
if (CE->getConstructor()->isTrivial() &&
CE->getConstructor()->isCopyOrMoveConstructor() &&
!IsArray) {
// 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);
}
ExplodedNodeSet DstPostCall;
getCheckerManager().runCheckersForPostCall(DstPostCall, DstEvaluated,
*Call, *this);
getCheckerManager().runCheckersForPostStmt(destNodes, DstPostCall, CE, *this);
}
void ExprEngine::VisitCXXDestructor(QualType ObjectType,
const MemRegion *Dest,
const Stmt *S,
bool IsBaseDtor,
ExplodedNode *Pred,
ExplodedNodeSet &Dst) {
const LocationContext *LCtx = Pred->getLocationContext();
ProgramStateRef State = Pred->getState();
// FIXME: We need to run the same destructor on every element of the array.
// This workaround will just run the first destructor (which will still
// invalidate the entire array).
// This is a loop because of multidimensional arrays.
while (const ArrayType *AT = getContext().getAsArrayType(ObjectType)) {
ObjectType = AT->getElementType();
Dest = State->getLValue(ObjectType, getSValBuilder().makeZeroArrayIndex(),
loc::MemRegionVal(Dest)).getAsRegion();
}
const CXXRecordDecl *RecordDecl = ObjectType->getAsCXXRecordDecl();
assert(RecordDecl && "Only CXXRecordDecls should have destructors");
const CXXDestructorDecl *DtorDecl = RecordDecl->getDestructor();
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);
ExplodedNodeSet DstPostCall;
getCheckerManager().runCheckersForPostCall(Dst, DstInvalidated,
*Call, *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.
StmtNodeBuilder Bldr(Pred, Dst, *currBldrCtx);
unsigned blockCount = currBldrCtx->blockCount();
const LocationContext *LCtx = Pred->getLocationContext();
DefinedOrUnknownSVal symVal = svalBuilder.conjureSymbolVal(0, CNE, LCtx,
CNE->getType(),
blockCount);
ProgramStateRef State = Pred->getState();
CallEventManager &CEMgr = getStateManager().getCallEventManager();
CallEventRef<CXXAllocatorCall> Call =
CEMgr.getCXXAllocatorCall(CNE, State, LCtx);
// 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 checks here.
State = Call->invalidateRegions(blockCount);
// If we're compiling with exceptions enabled, and this allocation function
// is not declared as non-throwing, failures /must/ be signalled by
// exceptions, and thus the return value will never be NULL.
// C++11 [basic.stc.dynamic.allocation]p3.
FunctionDecl *FD = CNE->getOperatorNew();
if (FD && getContext().getLangOpts().CXXExceptions) {
QualType Ty = FD->getType();
if (const FunctionProtoType *ProtoType = Ty->getAs<FunctionProtoType>())
if (!ProtoType->isNothrow(getContext()))
State = State->assume(symVal, true);
}
if (CNE->isArray()) {
// FIXME: allocating an array requires simulating the constructors.
// For now, just return a symbolicated region.
const MemRegion *NewReg = symVal.castAs<loc::MemRegionVal>().getRegion();
QualType ObjTy = CNE->getType()->getAs<PointerType>()->getPointeeType();
const ElementRegion *EleReg =
getStoreManager().GetElementZeroRegion(NewReg, ObjTy);
State = State->BindExpr(CNE, Pred->getLocationContext(),
loc::MemRegionVal(EleReg));
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);
SVal Result = svalBuilder.evalCast(PlacementLoc, CNE->getType(),
CNE->getPlacementArg(0)->getType());
State = State->BindExpr(CNE, LCtx, Result);
} else {
State = State->BindExpr(CNE, LCtx, symVal);
}
// 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)) {
QualType ObjTy = CNE->getType()->getAs<PointerType>()->getPointeeType();
(void)ObjTy;
assert(!ObjTy->isRecordType());
SVal Location = State->getSVal(CNE, LCtx);
if (Optional<Loc> LV = Location.getAs<Loc>())
State = State->bindLoc(*LV, State->getSVal(Init, LCtx));
}
}
Bldr.generateNode(CNE, Pred, State);
}
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);
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));
}