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

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//===- Calls.cpp - Wrapper for all function and method calls ------*- C++ -*--//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
/// \file This file defines CallEvent and its subclasses, which represent path-
/// sensitive instances of different kinds of function and method calls
/// (C, C++, and Objective-C).
//
//===----------------------------------------------------------------------===//
#include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h"
#include "clang/AST/ParentMap.h"
#include "clang/Analysis/ProgramPoint.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/DynamicTypeMap.h"
#include "llvm/ADT/SmallSet.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/Support/raw_ostream.h"
using namespace clang;
using namespace ento;
QualType CallEvent::getResultType() const {
const Expr *E = getOriginExpr();
assert(E && "Calls without origin expressions do not have results");
QualType ResultTy = E->getType();
ASTContext &Ctx = getState()->getStateManager().getContext();
// A function that returns a reference to 'int' will have a result type
// of simply 'int'. Check the origin expr's value kind to recover the
// proper type.
switch (E->getValueKind()) {
case VK_LValue:
ResultTy = Ctx.getLValueReferenceType(ResultTy);
break;
case VK_XValue:
ResultTy = Ctx.getRValueReferenceType(ResultTy);
break;
case VK_RValue:
// No adjustment is necessary.
break;
}
return ResultTy;
}
static bool isCallback(QualType T) {
// If a parameter is a block or a callback, assume it can modify pointer.
if (T->isBlockPointerType() ||
T->isFunctionPointerType() ||
T->isObjCSelType())
return true;
// Check if a callback is passed inside a struct (for both, struct passed by
// reference and by value). Dig just one level into the struct for now.
if (T->isAnyPointerType() || T->isReferenceType())
T = T->getPointeeType();
if (const RecordType *RT = T->getAsStructureType()) {
const RecordDecl *RD = RT->getDecl();
for (const auto *I : RD->fields()) {
QualType FieldT = I->getType();
if (FieldT->isBlockPointerType() || FieldT->isFunctionPointerType())
return true;
}
}
return false;
}
static bool isVoidPointerToNonConst(QualType T) {
if (const PointerType *PT = T->getAs<PointerType>()) {
QualType PointeeTy = PT->getPointeeType();
if (PointeeTy.isConstQualified())
return false;
return PointeeTy->isVoidType();
} else
return false;
}
bool CallEvent::hasNonNullArgumentsWithType(bool (*Condition)(QualType)) const {
unsigned NumOfArgs = getNumArgs();
// If calling using a function pointer, assume the function does not
// satisfy the callback.
// TODO: We could check the types of the arguments here.
if (!getDecl())
return false;
unsigned Idx = 0;
for (CallEvent::param_type_iterator I = param_type_begin(),
E = param_type_end();
I != E && Idx < NumOfArgs; ++I, ++Idx) {
if (NumOfArgs <= Idx)
break;
// If the parameter is 0, it's harmless.
if (getArgSVal(Idx).isZeroConstant())
continue;
if (Condition(*I))
return true;
}
return false;
}
bool CallEvent::hasNonZeroCallbackArg() const {
return hasNonNullArgumentsWithType(isCallback);
}
bool CallEvent::hasVoidPointerToNonConstArg() const {
return hasNonNullArgumentsWithType(isVoidPointerToNonConst);
}
bool CallEvent::isGlobalCFunction(StringRef FunctionName) const {
const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(getDecl());
if (!FD)
return false;
return CheckerContext::isCLibraryFunction(FD, FunctionName);
}
/// \brief Returns true if a type is a pointer-to-const or reference-to-const
/// with no further indirection.
static bool isPointerToConst(QualType Ty) {
QualType PointeeTy = Ty->getPointeeType();
if (PointeeTy == QualType())
return false;
if (!PointeeTy.isConstQualified())
return false;
if (PointeeTy->isAnyPointerType())
return false;
return true;
}
// Try to retrieve the function declaration and find the function parameter
// types which are pointers/references to a non-pointer const.
// We will not invalidate the corresponding argument regions.
static void findPtrToConstParams(llvm::SmallSet<unsigned, 4> &PreserveArgs,
const CallEvent &Call) {
unsigned Idx = 0;
for (CallEvent::param_type_iterator I = Call.param_type_begin(),
E = Call.param_type_end();
I != E; ++I, ++Idx) {
if (isPointerToConst(*I))
PreserveArgs.insert(Idx);
}
}
ProgramStateRef CallEvent::invalidateRegions(unsigned BlockCount,
ProgramStateRef Orig) const {
ProgramStateRef Result = (Orig ? Orig : getState());
// Don't invalidate anything if the callee is marked pure/const.
if (const Decl *callee = getDecl())
if (callee->hasAttr<PureAttr>() || callee->hasAttr<ConstAttr>())
return Result;
SmallVector<SVal, 8> ValuesToInvalidate;
RegionAndSymbolInvalidationTraits ETraits;
getExtraInvalidatedValues(ValuesToInvalidate, &ETraits);
// Indexes of arguments whose values will be preserved by the call.
llvm::SmallSet<unsigned, 4> PreserveArgs;
if (!argumentsMayEscape())
findPtrToConstParams(PreserveArgs, *this);
for (unsigned Idx = 0, Count = getNumArgs(); Idx != Count; ++Idx) {
// Mark this region for invalidation. We batch invalidate regions
// below for efficiency.
if (PreserveArgs.count(Idx))
if (const MemRegion *MR = getArgSVal(Idx).getAsRegion())
ETraits.setTrait(MR->getBaseRegion(),
RegionAndSymbolInvalidationTraits::TK_PreserveContents);
// TODO: Factor this out + handle the lower level const pointers.
ValuesToInvalidate.push_back(getArgSVal(Idx));
}
// Invalidate designated regions using the batch invalidation API.
// NOTE: Even if RegionsToInvalidate is empty, we may still invalidate
// global variables.
return Result->invalidateRegions(ValuesToInvalidate, getOriginExpr(),
BlockCount, getLocationContext(),
/*CausedByPointerEscape*/ true,
/*Symbols=*/nullptr, this, &ETraits);
}
ProgramPoint CallEvent::getProgramPoint(bool IsPreVisit,
const ProgramPointTag *Tag) const {
if (const Expr *E = getOriginExpr()) {
if (IsPreVisit)
return PreStmt(E, getLocationContext(), Tag);
return PostStmt(E, getLocationContext(), Tag);
}
const Decl *D = getDecl();
assert(D && "Cannot get a program point without a statement or decl");
SourceLocation Loc = getSourceRange().getBegin();
if (IsPreVisit)
return PreImplicitCall(D, Loc, getLocationContext(), Tag);
return PostImplicitCall(D, Loc, getLocationContext(), Tag);
}
bool CallEvent::isCalled(const CallDescription &CD) const {
assert(getKind() != CE_ObjCMessage && "Obj-C methods are not supported");
if (!CD.II)
CD.II = &getState()->getStateManager().getContext().Idents.get(CD.FuncName);
if (getCalleeIdentifier() != CD.II)
return false;
return (CD.RequiredArgs == CallDescription::NoArgRequirement ||
CD.RequiredArgs == getNumArgs());
}
SVal CallEvent::getArgSVal(unsigned Index) const {
const Expr *ArgE = getArgExpr(Index);
if (!ArgE)
return UnknownVal();
return getSVal(ArgE);
}
SourceRange CallEvent::getArgSourceRange(unsigned Index) const {
const Expr *ArgE = getArgExpr(Index);
if (!ArgE)
return SourceRange();
return ArgE->getSourceRange();
}
SVal CallEvent::getReturnValue() const {
const Expr *E = getOriginExpr();
if (!E)
return UndefinedVal();
return getSVal(E);
}
LLVM_DUMP_METHOD void CallEvent::dump() const { dump(llvm::errs()); }
void CallEvent::dump(raw_ostream &Out) const {
ASTContext &Ctx = getState()->getStateManager().getContext();
if (const Expr *E = getOriginExpr()) {
E->printPretty(Out, nullptr, Ctx.getPrintingPolicy());
Out << "\n";
return;
}
if (const Decl *D = getDecl()) {
Out << "Call to ";
D->print(Out, Ctx.getPrintingPolicy());
return;
}
// FIXME: a string representation of the kind would be nice.
Out << "Unknown call (type " << getKind() << ")";
}
bool CallEvent::isCallStmt(const Stmt *S) {
return isa<CallExpr>(S) || isa<ObjCMessageExpr>(S)
|| isa<CXXConstructExpr>(S)
|| isa<CXXNewExpr>(S);
}
QualType CallEvent::getDeclaredResultType(const Decl *D) {
assert(D);
if (const FunctionDecl* FD = dyn_cast<FunctionDecl>(D))
return FD->getReturnType();
if (const ObjCMethodDecl* MD = dyn_cast<ObjCMethodDecl>(D))
return MD->getReturnType();
if (const BlockDecl *BD = dyn_cast<BlockDecl>(D)) {
// Blocks are difficult because the return type may not be stored in the
// BlockDecl itself. The AST should probably be enhanced, but for now we
// just do what we can.
// If the block is declared without an explicit argument list, the
// signature-as-written just includes the return type, not the entire
// function type.
// FIXME: All blocks should have signatures-as-written, even if the return
// type is inferred. (That's signified with a dependent result type.)
if (const TypeSourceInfo *TSI = BD->getSignatureAsWritten()) {
QualType Ty = TSI->getType();
if (const FunctionType *FT = Ty->getAs<FunctionType>())
Ty = FT->getReturnType();
if (!Ty->isDependentType())
return Ty;
}
return QualType();
}
llvm_unreachable("unknown callable kind");
}
bool CallEvent::isVariadic(const Decl *D) {
assert(D);
if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D))
return FD->isVariadic();
if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D))
return MD->isVariadic();
if (const BlockDecl *BD = dyn_cast<BlockDecl>(D))
return BD->isVariadic();
llvm_unreachable("unknown callable kind");
}
static void addParameterValuesToBindings(const StackFrameContext *CalleeCtx,
CallEvent::BindingsTy &Bindings,
SValBuilder &SVB,
const CallEvent &Call,
ArrayRef<ParmVarDecl*> parameters) {
MemRegionManager &MRMgr = SVB.getRegionManager();
// If the function has fewer parameters than the call has arguments, we simply
// do not bind any values to them.
unsigned NumArgs = Call.getNumArgs();
unsigned Idx = 0;
ArrayRef<ParmVarDecl*>::iterator I = parameters.begin(), E = parameters.end();
for (; I != E && Idx < NumArgs; ++I, ++Idx) {
const ParmVarDecl *ParamDecl = *I;
assert(ParamDecl && "Formal parameter has no decl?");
SVal ArgVal = Call.getArgSVal(Idx);
if (!ArgVal.isUnknown()) {
Loc ParamLoc = SVB.makeLoc(MRMgr.getVarRegion(ParamDecl, CalleeCtx));
Bindings.push_back(std::make_pair(ParamLoc, ArgVal));
}
}
// FIXME: Variadic arguments are not handled at all right now.
}
ArrayRef<ParmVarDecl*> AnyFunctionCall::parameters() const {
const FunctionDecl *D = getDecl();
if (!D)
return None;
return D->parameters();
}
void AnyFunctionCall::getInitialStackFrameContents(
const StackFrameContext *CalleeCtx,
BindingsTy &Bindings) const {
const FunctionDecl *D = cast<FunctionDecl>(CalleeCtx->getDecl());
SValBuilder &SVB = getState()->getStateManager().getSValBuilder();
addParameterValuesToBindings(CalleeCtx, Bindings, SVB, *this,
D->parameters());
}
bool AnyFunctionCall::argumentsMayEscape() const {
if (CallEvent::argumentsMayEscape() || hasVoidPointerToNonConstArg())
return true;
const FunctionDecl *D = getDecl();
if (!D)
return true;
const IdentifierInfo *II = D->getIdentifier();
if (!II)
return false;
// This set of "escaping" APIs is
// - 'int pthread_setspecific(ptheread_key k, const void *)' stores a
// value into thread local storage. The value can later be retrieved with
// 'void *ptheread_getspecific(pthread_key)'. So even thought the
// parameter is 'const void *', the region escapes through the call.
if (II->isStr("pthread_setspecific"))
return true;
// - xpc_connection_set_context stores a value which can be retrieved later
// with xpc_connection_get_context.
if (II->isStr("xpc_connection_set_context"))
return true;
// - funopen - sets a buffer for future IO calls.
if (II->isStr("funopen"))
return true;
StringRef FName = II->getName();
// - CoreFoundation functions that end with "NoCopy" can free a passed-in
// buffer even if it is const.
if (FName.endswith("NoCopy"))
return true;
// - NSXXInsertXX, for example NSMapInsertIfAbsent, since they can
// be deallocated by NSMapRemove.
if (FName.startswith("NS") && (FName.find("Insert") != StringRef::npos))
return true;
// - Many CF containers allow objects to escape through custom
// allocators/deallocators upon container construction. (PR12101)
if (FName.startswith("CF") || FName.startswith("CG")) {
return StrInStrNoCase(FName, "InsertValue") != StringRef::npos ||
StrInStrNoCase(FName, "AddValue") != StringRef::npos ||
StrInStrNoCase(FName, "SetValue") != StringRef::npos ||
StrInStrNoCase(FName, "WithData") != StringRef::npos ||
StrInStrNoCase(FName, "AppendValue") != StringRef::npos ||
StrInStrNoCase(FName, "SetAttribute") != StringRef::npos;
}
return false;
}
const FunctionDecl *SimpleFunctionCall::getDecl() const {
const FunctionDecl *D = getOriginExpr()->getDirectCallee();
if (D)
return D;
return getSVal(getOriginExpr()->getCallee()).getAsFunctionDecl();
}
const FunctionDecl *CXXInstanceCall::getDecl() const {
const CallExpr *CE = cast_or_null<CallExpr>(getOriginExpr());
if (!CE)
return AnyFunctionCall::getDecl();
const FunctionDecl *D = CE->getDirectCallee();
if (D)
return D;
return getSVal(CE->getCallee()).getAsFunctionDecl();
}
void CXXInstanceCall::getExtraInvalidatedValues(
ValueList &Values, RegionAndSymbolInvalidationTraits *ETraits) const {
SVal ThisVal = getCXXThisVal();
Values.push_back(ThisVal);
// Don't invalidate if the method is const and there are no mutable fields.
if (const CXXMethodDecl *D = cast_or_null<CXXMethodDecl>(getDecl())) {
if (!D->isConst())
return;
// Get the record decl for the class of 'This'. D->getParent() may return a
// base class decl, rather than the class of the instance which needs to be
// checked for mutable fields.
const Expr *Ex = getCXXThisExpr()->ignoreParenBaseCasts();
const CXXRecordDecl *ParentRecord = Ex->getType()->getAsCXXRecordDecl();
if (!ParentRecord || ParentRecord->hasMutableFields())
return;
// Preserve CXXThis.
const MemRegion *ThisRegion = ThisVal.getAsRegion();
if (!ThisRegion)
return;
ETraits->setTrait(ThisRegion->getBaseRegion(),
RegionAndSymbolInvalidationTraits::TK_PreserveContents);
}
}
SVal CXXInstanceCall::getCXXThisVal() const {
const Expr *Base = getCXXThisExpr();
// FIXME: This doesn't handle an overloaded ->* operator.
if (!Base)
return UnknownVal();
SVal ThisVal = getSVal(Base);
assert(ThisVal.isUnknownOrUndef() || ThisVal.getAs<Loc>());
return ThisVal;
}
RuntimeDefinition CXXInstanceCall::getRuntimeDefinition() const {
// Do we have a decl at all?
const Decl *D = getDecl();
if (!D)
return RuntimeDefinition();
// If the method is non-virtual, we know we can inline it.
const CXXMethodDecl *MD = cast<CXXMethodDecl>(D);
if (!MD->isVirtual())
return AnyFunctionCall::getRuntimeDefinition();
// Do we know the implicit 'this' object being called?
const MemRegion *R = getCXXThisVal().getAsRegion();
if (!R)
return RuntimeDefinition();
// Do we know anything about the type of 'this'?
DynamicTypeInfo DynType = getDynamicTypeInfo(getState(), R);
if (!DynType.isValid())
return RuntimeDefinition();
// Is the type a C++ class? (This is mostly a defensive check.)
QualType RegionType = DynType.getType()->getPointeeType();
assert(!RegionType.isNull() && "DynamicTypeInfo should always be a pointer.");
const CXXRecordDecl *RD = RegionType->getAsCXXRecordDecl();
if (!RD || !RD->hasDefinition())
return RuntimeDefinition();
// Find the decl for this method in that class.
const CXXMethodDecl *Result = MD->getCorrespondingMethodInClass(RD, true);
if (!Result) {
// We might not even get the original statically-resolved method due to
// some particularly nasty casting (e.g. casts to sister classes).
// However, we should at least be able to search up and down our own class
// hierarchy, and some real bugs have been caught by checking this.
assert(!RD->isDerivedFrom(MD->getParent()) && "Couldn't find known method");
// FIXME: This is checking that our DynamicTypeInfo is at least as good as
// the static type. However, because we currently don't update
// DynamicTypeInfo when an object is cast, we can't actually be sure the
// DynamicTypeInfo is up to date. This assert should be re-enabled once
// this is fixed. <rdar://problem/12287087>
//assert(!MD->getParent()->isDerivedFrom(RD) && "Bad DynamicTypeInfo");
return RuntimeDefinition();
}
// Does the decl that we found have an implementation?
const FunctionDecl *Definition;
if (!Result->hasBody(Definition))
return RuntimeDefinition();
// We found a definition. If we're not sure that this devirtualization is
// actually what will happen at runtime, make sure to provide the region so
// that ExprEngine can decide what to do with it.
if (DynType.canBeASubClass())
return RuntimeDefinition(Definition, R->StripCasts());
return RuntimeDefinition(Definition, /*DispatchRegion=*/nullptr);
}
void CXXInstanceCall::getInitialStackFrameContents(
const StackFrameContext *CalleeCtx,
BindingsTy &Bindings) const {
AnyFunctionCall::getInitialStackFrameContents(CalleeCtx, Bindings);
// Handle the binding of 'this' in the new stack frame.
SVal ThisVal = getCXXThisVal();
if (!ThisVal.isUnknown()) {
ProgramStateManager &StateMgr = getState()->getStateManager();
SValBuilder &SVB = StateMgr.getSValBuilder();
const CXXMethodDecl *MD = cast<CXXMethodDecl>(CalleeCtx->getDecl());
Loc ThisLoc = SVB.getCXXThis(MD, CalleeCtx);
// If we devirtualized to a different member function, we need to make sure
// we have the proper layering of CXXBaseObjectRegions.
if (MD->getCanonicalDecl() != getDecl()->getCanonicalDecl()) {
ASTContext &Ctx = SVB.getContext();
const CXXRecordDecl *Class = MD->getParent();
QualType Ty = Ctx.getPointerType(Ctx.getRecordType(Class));
// FIXME: CallEvent maybe shouldn't be directly accessing StoreManager.
bool Failed;
ThisVal = StateMgr.getStoreManager().attemptDownCast(ThisVal, Ty, Failed);
assert(!Failed && "Calling an incorrectly devirtualized method");
}
if (!ThisVal.isUnknown())
Bindings.push_back(std::make_pair(ThisLoc, ThisVal));
}
}
const Expr *CXXMemberCall::getCXXThisExpr() const {
return getOriginExpr()->getImplicitObjectArgument();
}
RuntimeDefinition CXXMemberCall::getRuntimeDefinition() const {
// C++11 [expr.call]p1: ...If the selected function is non-virtual, or if the
// id-expression in the class member access expression is a qualified-id,
// that function is called. Otherwise, its final overrider in the dynamic type
// of the object expression is called.
if (const MemberExpr *ME = dyn_cast<MemberExpr>(getOriginExpr()->getCallee()))
if (ME->hasQualifier())
return AnyFunctionCall::getRuntimeDefinition();
return CXXInstanceCall::getRuntimeDefinition();
}
const Expr *CXXMemberOperatorCall::getCXXThisExpr() const {
return getOriginExpr()->getArg(0);
}
const BlockDataRegion *BlockCall::getBlockRegion() const {
const Expr *Callee = getOriginExpr()->getCallee();
const MemRegion *DataReg = getSVal(Callee).getAsRegion();
return dyn_cast_or_null<BlockDataRegion>(DataReg);
}
ArrayRef<ParmVarDecl*> BlockCall::parameters() const {
const BlockDecl *D = getDecl();
if (!D)
return nullptr;
return D->parameters();
}
void BlockCall::getExtraInvalidatedValues(ValueList &Values,
RegionAndSymbolInvalidationTraits *ETraits) const {
// FIXME: This also needs to invalidate captured globals.
if (const MemRegion *R = getBlockRegion())
Values.push_back(loc::MemRegionVal(R));
}
void BlockCall::getInitialStackFrameContents(const StackFrameContext *CalleeCtx,
BindingsTy &Bindings) const {
SValBuilder &SVB = getState()->getStateManager().getSValBuilder();
ArrayRef<ParmVarDecl*> Params;
if (isConversionFromLambda()) {
auto *LambdaOperatorDecl = cast<CXXMethodDecl>(CalleeCtx->getDecl());
Params = LambdaOperatorDecl->parameters();
// For blocks converted from a C++ lambda, the callee declaration is the
// operator() method on the lambda so we bind "this" to
// the lambda captured by the block.
const VarRegion *CapturedLambdaRegion = getRegionStoringCapturedLambda();
SVal ThisVal = loc::MemRegionVal(CapturedLambdaRegion);
Loc ThisLoc = SVB.getCXXThis(LambdaOperatorDecl, CalleeCtx);
Bindings.push_back(std::make_pair(ThisLoc, ThisVal));
} else {
Params = cast<BlockDecl>(CalleeCtx->getDecl())->parameters();
}
addParameterValuesToBindings(CalleeCtx, Bindings, SVB, *this,
Params);
}
SVal CXXConstructorCall::getCXXThisVal() const {
if (Data)
return loc::MemRegionVal(static_cast<const MemRegion *>(Data));
return UnknownVal();
}
void CXXConstructorCall::getExtraInvalidatedValues(ValueList &Values,
RegionAndSymbolInvalidationTraits *ETraits) const {
if (Data)
Values.push_back(loc::MemRegionVal(static_cast<const MemRegion *>(Data)));
}
void CXXConstructorCall::getInitialStackFrameContents(
const StackFrameContext *CalleeCtx,
BindingsTy &Bindings) const {
AnyFunctionCall::getInitialStackFrameContents(CalleeCtx, Bindings);
SVal ThisVal = getCXXThisVal();
if (!ThisVal.isUnknown()) {
SValBuilder &SVB = getState()->getStateManager().getSValBuilder();
const CXXMethodDecl *MD = cast<CXXMethodDecl>(CalleeCtx->getDecl());
Loc ThisLoc = SVB.getCXXThis(MD, CalleeCtx);
Bindings.push_back(std::make_pair(ThisLoc, ThisVal));
}
}
SVal CXXDestructorCall::getCXXThisVal() const {
if (Data)
return loc::MemRegionVal(DtorDataTy::getFromOpaqueValue(Data).getPointer());
return UnknownVal();
}
RuntimeDefinition CXXDestructorCall::getRuntimeDefinition() const {
// Base destructors are always called non-virtually.
// Skip CXXInstanceCall's devirtualization logic in this case.
if (isBaseDestructor())
return AnyFunctionCall::getRuntimeDefinition();
return CXXInstanceCall::getRuntimeDefinition();
}
ArrayRef<ParmVarDecl*> ObjCMethodCall::parameters() const {
const ObjCMethodDecl *D = getDecl();
if (!D)
return None;
return D->parameters();
}
void ObjCMethodCall::getExtraInvalidatedValues(
ValueList &Values, RegionAndSymbolInvalidationTraits *ETraits) const {
// If the method call is a setter for property known to be backed by
// an instance variable, don't invalidate the entire receiver, just
// the storage for that instance variable.
if (const ObjCPropertyDecl *PropDecl = getAccessedProperty()) {
if (const ObjCIvarDecl *PropIvar = PropDecl->getPropertyIvarDecl()) {
SVal IvarLVal = getState()->getLValue(PropIvar, getReceiverSVal());
const MemRegion *IvarRegion = IvarLVal.getAsRegion();
ETraits->setTrait(
IvarRegion,
RegionAndSymbolInvalidationTraits::TK_DoNotInvalidateSuperRegion);
ETraits->setTrait(IvarRegion,
RegionAndSymbolInvalidationTraits::TK_SuppressEscape);
Values.push_back(IvarLVal);
return;
}
}
Values.push_back(getReceiverSVal());
}
SVal ObjCMethodCall::getSelfSVal() const {
const LocationContext *LCtx = getLocationContext();
const ImplicitParamDecl *SelfDecl = LCtx->getSelfDecl();
if (!SelfDecl)
return SVal();
return getState()->getSVal(getState()->getRegion(SelfDecl, LCtx));
}
SVal ObjCMethodCall::getReceiverSVal() const {
// FIXME: Is this the best way to handle class receivers?
if (!isInstanceMessage())
return UnknownVal();
if (const Expr *RecE = getOriginExpr()->getInstanceReceiver())
return getSVal(RecE);
// An instance message with no expression means we are sending to super.
// In this case the object reference is the same as 'self'.
assert(getOriginExpr()->getReceiverKind() == ObjCMessageExpr::SuperInstance);
SVal SelfVal = getSelfSVal();
assert(SelfVal.isValid() && "Calling super but not in ObjC method");
return SelfVal;
}
bool ObjCMethodCall::isReceiverSelfOrSuper() const {
if (getOriginExpr()->getReceiverKind() == ObjCMessageExpr::SuperInstance ||
getOriginExpr()->getReceiverKind() == ObjCMessageExpr::SuperClass)
return true;
if (!isInstanceMessage())
return false;
SVal RecVal = getSVal(getOriginExpr()->getInstanceReceiver());
return (RecVal == getSelfSVal());
}
SourceRange ObjCMethodCall::getSourceRange() const {
switch (getMessageKind()) {
case OCM_Message:
return getOriginExpr()->getSourceRange();
case OCM_PropertyAccess:
case OCM_Subscript:
return getContainingPseudoObjectExpr()->getSourceRange();
}
llvm_unreachable("unknown message kind");
}
typedef llvm::PointerIntPair<const PseudoObjectExpr *, 2> ObjCMessageDataTy;
const PseudoObjectExpr *ObjCMethodCall::getContainingPseudoObjectExpr() const {
assert(Data && "Lazy lookup not yet performed.");
assert(getMessageKind() != OCM_Message && "Explicit message send.");
return ObjCMessageDataTy::getFromOpaqueValue(Data).getPointer();
}
static const Expr *
getSyntacticFromForPseudoObjectExpr(const PseudoObjectExpr *POE) {
const Expr *Syntactic = POE->getSyntacticForm();
// This handles the funny case of assigning to the result of a getter.
// This can happen if the getter returns a non-const reference.
if (const BinaryOperator *BO = dyn_cast<BinaryOperator>(Syntactic))
Syntactic = BO->getLHS();
return Syntactic;
}
ObjCMessageKind ObjCMethodCall::getMessageKind() const {
if (!Data) {
// Find the parent, ignoring implicit casts.
ParentMap &PM = getLocationContext()->getParentMap();
const Stmt *S = PM.getParentIgnoreParenCasts(getOriginExpr());
// Check if parent is a PseudoObjectExpr.
if (const PseudoObjectExpr *POE = dyn_cast_or_null<PseudoObjectExpr>(S)) {
const Expr *Syntactic = getSyntacticFromForPseudoObjectExpr(POE);
ObjCMessageKind K;
switch (Syntactic->getStmtClass()) {
case Stmt::ObjCPropertyRefExprClass:
K = OCM_PropertyAccess;
break;
case Stmt::ObjCSubscriptRefExprClass:
K = OCM_Subscript;
break;
default:
// FIXME: Can this ever happen?
K = OCM_Message;
break;
}
if (K != OCM_Message) {
const_cast<ObjCMethodCall *>(this)->Data
= ObjCMessageDataTy(POE, K).getOpaqueValue();
assert(getMessageKind() == K);
return K;
}
}
const_cast<ObjCMethodCall *>(this)->Data
= ObjCMessageDataTy(nullptr, 1).getOpaqueValue();
assert(getMessageKind() == OCM_Message);
return OCM_Message;
}
ObjCMessageDataTy Info = ObjCMessageDataTy::getFromOpaqueValue(Data);
if (!Info.getPointer())
return OCM_Message;
return static_cast<ObjCMessageKind>(Info.getInt());
}
const ObjCPropertyDecl *ObjCMethodCall::getAccessedProperty() const {
// Look for properties accessed with property syntax (foo.bar = ...)
if ( getMessageKind() == OCM_PropertyAccess) {
const PseudoObjectExpr *POE = getContainingPseudoObjectExpr();
assert(POE && "Property access without PseudoObjectExpr?");
const Expr *Syntactic = getSyntacticFromForPseudoObjectExpr(POE);
auto *RefExpr = cast<ObjCPropertyRefExpr>(Syntactic);
if (RefExpr->isExplicitProperty())
return RefExpr->getExplicitProperty();
}
// Look for properties accessed with method syntax ([foo setBar:...]).
const ObjCMethodDecl *MD = getDecl();
if (!MD || !MD->isPropertyAccessor())
return nullptr;
// Note: This is potentially quite slow.
return MD->findPropertyDecl();
}
bool ObjCMethodCall::canBeOverridenInSubclass(ObjCInterfaceDecl *IDecl,
Selector Sel) const {
assert(IDecl);
const SourceManager &SM =
getState()->getStateManager().getContext().getSourceManager();
// If the class interface is declared inside the main file, assume it is not
// subcassed.
// TODO: It could actually be subclassed if the subclass is private as well.
// This is probably very rare.
SourceLocation InterfLoc = IDecl->getEndOfDefinitionLoc();
if (InterfLoc.isValid() && SM.isInMainFile(InterfLoc))
return false;
// Assume that property accessors are not overridden.
if (getMessageKind() == OCM_PropertyAccess)
return false;
// We assume that if the method is public (declared outside of main file) or
// has a parent which publicly declares the method, the method could be
// overridden in a subclass.
// Find the first declaration in the class hierarchy that declares
// the selector.
ObjCMethodDecl *D = nullptr;
while (true) {
D = IDecl->lookupMethod(Sel, true);
// Cannot find a public definition.
if (!D)
return false;
// If outside the main file,
if (D->getLocation().isValid() && !SM.isInMainFile(D->getLocation()))
return true;
if (D->isOverriding()) {
// Search in the superclass on the next iteration.
IDecl = D->getClassInterface();
if (!IDecl)
return false;
IDecl = IDecl->getSuperClass();
if (!IDecl)
return false;
continue;
}
return false;
};
llvm_unreachable("The while loop should always terminate.");
}
RuntimeDefinition ObjCMethodCall::getRuntimeDefinition() const {
const ObjCMessageExpr *E = getOriginExpr();
assert(E);
Selector Sel = E->getSelector();
if (E->isInstanceMessage()) {
// Find the receiver type.
const ObjCObjectPointerType *ReceiverT = nullptr;
bool CanBeSubClassed = false;
QualType SupersType = E->getSuperType();
const MemRegion *Receiver = nullptr;
if (!SupersType.isNull()) {
// Super always means the type of immediate predecessor to the method
// where the call occurs.
ReceiverT = cast<ObjCObjectPointerType>(SupersType);
} else {
Receiver = getReceiverSVal().getAsRegion();
if (!Receiver)
return RuntimeDefinition();
DynamicTypeInfo DTI = getDynamicTypeInfo(getState(), Receiver);
QualType DynType = DTI.getType();
CanBeSubClassed = DTI.canBeASubClass();
ReceiverT = dyn_cast<ObjCObjectPointerType>(DynType);
if (ReceiverT && CanBeSubClassed)
if (ObjCInterfaceDecl *IDecl = ReceiverT->getInterfaceDecl())
if (!canBeOverridenInSubclass(IDecl, Sel))
CanBeSubClassed = false;
}
// Lookup the method implementation.
if (ReceiverT)
if (ObjCInterfaceDecl *IDecl = ReceiverT->getInterfaceDecl()) {
// Repeatedly calling lookupPrivateMethod() is expensive, especially
// when in many cases it returns null. We cache the results so
// that repeated queries on the same ObjCIntefaceDecl and Selector
// don't incur the same cost. On some test cases, we can see the
// same query being issued thousands of times.
//
// NOTE: This cache is essentially a "global" variable, but it
// only gets lazily created when we get here. The value of the
// cache probably comes from it being global across ExprEngines,
// where the same queries may get issued. If we are worried about
// concurrency, or possibly loading/unloading ASTs, etc., we may
// need to revisit this someday. In terms of memory, this table
// stays around until clang quits, which also may be bad if we
// need to release memory.
typedef std::pair<const ObjCInterfaceDecl*, Selector>
PrivateMethodKey;
typedef llvm::DenseMap<PrivateMethodKey,
Optional<const ObjCMethodDecl *> >
PrivateMethodCache;
static PrivateMethodCache PMC;
Optional<const ObjCMethodDecl *> &Val = PMC[std::make_pair(IDecl, Sel)];
// Query lookupPrivateMethod() if the cache does not hit.
if (!Val.hasValue()) {
Val = IDecl->lookupPrivateMethod(Sel);
// If the method is a property accessor, we should try to "inline" it
// even if we don't actually have an implementation.
if (!*Val)
if (const ObjCMethodDecl *CompileTimeMD = E->getMethodDecl())
if (CompileTimeMD->isPropertyAccessor()) {
if (!CompileTimeMD->getSelfDecl() &&
isa<ObjCCategoryDecl>(CompileTimeMD->getDeclContext())) {
// If the method is an accessor in a category, and it doesn't
// have a self declaration, first
// try to find the method in a class extension. This
// works around a bug in Sema where multiple accessors
// are synthesized for properties in class
// extensions that are redeclared in a category and the
// the implicit parameters are not filled in for
// the method on the category.
// This ensures we find the accessor in the extension, which
// has the implicit parameters filled in.
auto *ID = CompileTimeMD->getClassInterface();
for (auto *CatDecl : ID->visible_extensions()) {
Val = CatDecl->getMethod(Sel,
CompileTimeMD->isInstanceMethod());
if (*Val)
break;
}
}
if (!*Val)
Val = IDecl->lookupInstanceMethod(Sel);
}
}
const ObjCMethodDecl *MD = Val.getValue();
if (CanBeSubClassed)
return RuntimeDefinition(MD, Receiver);
else
return RuntimeDefinition(MD, nullptr);
}
} else {
// This is a class method.
// If we have type info for the receiver class, we are calling via
// class name.
if (ObjCInterfaceDecl *IDecl = E->getReceiverInterface()) {
// Find/Return the method implementation.
return RuntimeDefinition(IDecl->lookupPrivateClassMethod(Sel));
}
}
return RuntimeDefinition();
}
bool ObjCMethodCall::argumentsMayEscape() const {
if (isInSystemHeader() && !isInstanceMessage()) {
Selector Sel = getSelector();
if (Sel.getNumArgs() == 1 &&
Sel.getIdentifierInfoForSlot(0)->isStr("valueWithPointer"))
return true;
}
return CallEvent::argumentsMayEscape();
}
void ObjCMethodCall::getInitialStackFrameContents(
const StackFrameContext *CalleeCtx,
BindingsTy &Bindings) const {
const ObjCMethodDecl *D = cast<ObjCMethodDecl>(CalleeCtx->getDecl());
SValBuilder &SVB = getState()->getStateManager().getSValBuilder();
addParameterValuesToBindings(CalleeCtx, Bindings, SVB, *this,
D->parameters());
SVal SelfVal = getReceiverSVal();
if (!SelfVal.isUnknown()) {
const VarDecl *SelfD = CalleeCtx->getAnalysisDeclContext()->getSelfDecl();
MemRegionManager &MRMgr = SVB.getRegionManager();
Loc SelfLoc = SVB.makeLoc(MRMgr.getVarRegion(SelfD, CalleeCtx));
Bindings.push_back(std::make_pair(SelfLoc, SelfVal));
}
}
CallEventRef<>
CallEventManager::getSimpleCall(const CallExpr *CE, ProgramStateRef State,
const LocationContext *LCtx) {
if (const CXXMemberCallExpr *MCE = dyn_cast<CXXMemberCallExpr>(CE))
return create<CXXMemberCall>(MCE, State, LCtx);
if (const CXXOperatorCallExpr *OpCE = dyn_cast<CXXOperatorCallExpr>(CE)) {
const FunctionDecl *DirectCallee = OpCE->getDirectCallee();
if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(DirectCallee))
if (MD->isInstance())
return create<CXXMemberOperatorCall>(OpCE, State, LCtx);
} else if (CE->getCallee()->getType()->isBlockPointerType()) {
return create<BlockCall>(CE, State, LCtx);
}
// Otherwise, it's a normal function call, static member function call, or
// something we can't reason about.
return create<SimpleFunctionCall>(CE, State, LCtx);
}
CallEventRef<>
CallEventManager::getCaller(const StackFrameContext *CalleeCtx,
ProgramStateRef State) {
const LocationContext *ParentCtx = CalleeCtx->getParent();
const LocationContext *CallerCtx = ParentCtx->getCurrentStackFrame();
assert(CallerCtx && "This should not be used for top-level stack frames");
const Stmt *CallSite = CalleeCtx->getCallSite();
if (CallSite) {
if (const CallExpr *CE = dyn_cast<CallExpr>(CallSite))
return getSimpleCall(CE, State, CallerCtx);
switch (CallSite->getStmtClass()) {
case Stmt::CXXConstructExprClass:
case Stmt::CXXTemporaryObjectExprClass: {
SValBuilder &SVB = State->getStateManager().getSValBuilder();
const CXXMethodDecl *Ctor = cast<CXXMethodDecl>(CalleeCtx->getDecl());
Loc ThisPtr = SVB.getCXXThis(Ctor, CalleeCtx);
SVal ThisVal = State->getSVal(ThisPtr);
return getCXXConstructorCall(cast<CXXConstructExpr>(CallSite),
ThisVal.getAsRegion(), State, CallerCtx);
}
case Stmt::CXXNewExprClass:
return getCXXAllocatorCall(cast<CXXNewExpr>(CallSite), State, CallerCtx);
case Stmt::ObjCMessageExprClass:
return getObjCMethodCall(cast<ObjCMessageExpr>(CallSite),
State, CallerCtx);
default:
llvm_unreachable("This is not an inlineable statement.");
}
}
// Fall back to the CFG. The only thing we haven't handled yet is
// destructors, though this could change in the future.
const CFGBlock *B = CalleeCtx->getCallSiteBlock();
CFGElement E = (*B)[CalleeCtx->getIndex()];
assert(E.getAs<CFGImplicitDtor>() &&
"All other CFG elements should have exprs");
assert(!E.getAs<CFGTemporaryDtor>() && "We don't handle temporaries yet");
SValBuilder &SVB = State->getStateManager().getSValBuilder();
const CXXDestructorDecl *Dtor = cast<CXXDestructorDecl>(CalleeCtx->getDecl());
Loc ThisPtr = SVB.getCXXThis(Dtor, CalleeCtx);
SVal ThisVal = State->getSVal(ThisPtr);
const Stmt *Trigger;
if (Optional<CFGAutomaticObjDtor> AutoDtor = E.getAs<CFGAutomaticObjDtor>())
Trigger = AutoDtor->getTriggerStmt();
else if (Optional<CFGDeleteDtor> DeleteDtor = E.getAs<CFGDeleteDtor>())
Trigger = cast<Stmt>(DeleteDtor->getDeleteExpr());
else
Trigger = Dtor->getBody();
return getCXXDestructorCall(Dtor, Trigger, ThisVal.getAsRegion(),
E.getAs<CFGBaseDtor>().hasValue(), State,
CallerCtx);
}
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