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

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//== RegionStore.cpp - Field-sensitive store model --------------*- 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 basic region store model. In this model, we do have field
// sensitivity. But we assume nothing about the heap shape. So recursive data
// structures are largely ignored. Basically we do 1-limiting analysis.
// Parameter pointers are assumed with no aliasing. Pointee objects of
// parameters are created lazily.
//
//===----------------------------------------------------------------------===//
#include "clang/Checker/PathSensitive/MemRegion.h"
#include "clang/Analysis/AnalysisContext.h"
#include "clang/Checker/PathSensitive/GRState.h"
#include "clang/Checker/PathSensitive/GRStateTrait.h"
#include "clang/Analysis/Analyses/LiveVariables.h"
#include "clang/Analysis/Support/Optional.h"
#include "clang/Basic/TargetInfo.h"
#include "clang/AST/CharUnits.h"
#include "llvm/ADT/ImmutableMap.h"
#include "llvm/ADT/ImmutableList.h"
#include "llvm/Support/raw_ostream.h"
using namespace clang;
#define USE_EXPLICIT_COMPOUND 0
//===----------------------------------------------------------------------===//
// Representation of binding keys.
//===----------------------------------------------------------------------===//
namespace {
class BindingKey {
public:
enum Kind { Direct = 0x0, Default = 0x1 };
private:
llvm ::PointerIntPair<const MemRegion*, 1> P;
uint64_t Offset;
explicit BindingKey(const MemRegion *r, uint64_t offset, Kind k)
: P(r, (unsigned) k), Offset(offset) { assert(r); }
public:
bool isDefault() const { return P.getInt() == Default; }
bool isDirect() const { return P.getInt() == Direct; }
const MemRegion *getRegion() const { return P.getPointer(); }
uint64_t getOffset() const { return Offset; }
void Profile(llvm::FoldingSetNodeID& ID) const {
ID.AddPointer(P.getOpaqueValue());
ID.AddInteger(Offset);
}
static BindingKey Make(const MemRegion *R, Kind k);
bool operator<(const BindingKey &X) const {
if (P.getOpaqueValue() < X.P.getOpaqueValue())
return true;
if (P.getOpaqueValue() > X.P.getOpaqueValue())
return false;
return Offset < X.Offset;
}
bool operator==(const BindingKey &X) const {
return P.getOpaqueValue() == X.P.getOpaqueValue() &&
Offset == X.Offset;
}
};
} // end anonymous namespace
namespace llvm {
static inline
llvm::raw_ostream& operator<<(llvm::raw_ostream& os, BindingKey K) {
os << '(' << K.getRegion() << ',' << K.getOffset()
<< ',' << (K.isDirect() ? "direct" : "default")
<< ')';
return os;
}
} // end llvm namespace
//===----------------------------------------------------------------------===//
// Actual Store type.
//===----------------------------------------------------------------------===//
typedef llvm::ImmutableMap<BindingKey, SVal> RegionBindings;
//===----------------------------------------------------------------------===//
// Fine-grained control of RegionStoreManager.
//===----------------------------------------------------------------------===//
namespace {
struct minimal_features_tag {};
struct maximal_features_tag {};
class RegionStoreFeatures {
bool SupportsFields;
bool SupportsRemaining;
public:
RegionStoreFeatures(minimal_features_tag) :
SupportsFields(false), SupportsRemaining(false) {}
RegionStoreFeatures(maximal_features_tag) :
SupportsFields(true), SupportsRemaining(false) {}
void enableFields(bool t) { SupportsFields = t; }
bool supportsFields() const { return SupportsFields; }
bool supportsRemaining() const { return SupportsRemaining; }
};
}
//===----------------------------------------------------------------------===//
// Region "Extents"
//===----------------------------------------------------------------------===//
//
// MemRegions represent chunks of memory with a size (their "extent"). This
// GDM entry tracks the extents for regions. Extents are in bytes.
//
namespace { class RegionExtents {}; }
static int RegionExtentsIndex = 0;
namespace clang {
template<> struct GRStateTrait<RegionExtents>
: public GRStatePartialTrait<llvm::ImmutableMap<const MemRegion*, SVal> > {
static void* GDMIndex() { return &RegionExtentsIndex; }
};
}
//===----------------------------------------------------------------------===//
// Utility functions.
//===----------------------------------------------------------------------===//
static bool IsAnyPointerOrIntptr(QualType ty, ASTContext &Ctx) {
if (ty->isAnyPointerType())
return true;
return ty->isIntegerType() && ty->isScalarType() &&
Ctx.getTypeSize(ty) == Ctx.getTypeSize(Ctx.VoidPtrTy);
}
//===----------------------------------------------------------------------===//
// Main RegionStore logic.
//===----------------------------------------------------------------------===//
namespace {
class RegionStoreSubRegionMap : public SubRegionMap {
public:
typedef llvm::ImmutableSet<const MemRegion*> Set;
typedef llvm::DenseMap<const MemRegion*, Set> Map;
private:
Set::Factory F;
Map M;
public:
bool add(const MemRegion* Parent, const MemRegion* SubRegion) {
Map::iterator I = M.find(Parent);
if (I == M.end()) {
M.insert(std::make_pair(Parent, F.Add(F.GetEmptySet(), SubRegion)));
return true;
}
I->second = F.Add(I->second, SubRegion);
return false;
}
void process(llvm::SmallVectorImpl<const SubRegion*> &WL, const SubRegion *R);
~RegionStoreSubRegionMap() {}
const Set *getSubRegions(const MemRegion *Parent) const {
Map::const_iterator I = M.find(Parent);
return I == M.end() ? NULL : &I->second;
}
bool iterSubRegions(const MemRegion* Parent, Visitor& V) const {
Map::const_iterator I = M.find(Parent);
if (I == M.end())
return true;
Set S = I->second;
for (Set::iterator SI=S.begin(),SE=S.end(); SI != SE; ++SI) {
if (!V.Visit(Parent, *SI))
return false;
}
return true;
}
};
class RegionStoreManager : public StoreManager {
const RegionStoreFeatures Features;
RegionBindings::Factory RBFactory;
typedef llvm::DenseMap<Store, RegionStoreSubRegionMap*> SMCache;
SMCache SC;
public:
RegionStoreManager(GRStateManager& mgr, const RegionStoreFeatures &f)
: StoreManager(mgr),
Features(f),
RBFactory(mgr.getAllocator()) {}
virtual ~RegionStoreManager() {
for (SMCache::iterator I = SC.begin(), E = SC.end(); I != E; ++I)
delete (*I).second;
}
SubRegionMap *getSubRegionMap(Store store) {
return getRegionStoreSubRegionMap(store);
}
RegionStoreSubRegionMap *getRegionStoreSubRegionMap(Store store);
Optional<SVal> getBinding(RegionBindings B, const MemRegion *R);
Optional<SVal> getDirectBinding(RegionBindings B, const MemRegion *R);
/// getDefaultBinding - Returns an SVal* representing an optional default
/// binding associated with a region and its subregions.
Optional<SVal> getDefaultBinding(RegionBindings B, const MemRegion *R);
/// setImplicitDefaultValue - Set the default binding for the provided
/// MemRegion to the value implicitly defined for compound literals when
/// the value is not specified.
Store setImplicitDefaultValue(Store store, const MemRegion *R, QualType T);
/// ArrayToPointer - Emulates the "decay" of an array to a pointer
/// type. 'Array' represents the lvalue of the array being decayed
/// to a pointer, and the returned SVal represents the decayed
/// version of that lvalue (i.e., a pointer to the first element of
/// the array). This is called by GRExprEngine when evaluating
/// casts from arrays to pointers.
SVal ArrayToPointer(Loc Array);
SVal EvalBinOp(BinaryOperator::Opcode Op,Loc L, NonLoc R, QualType resultTy);
Store getInitialStore(const LocationContext *InitLoc) {
return RBFactory.GetEmptyMap().getRoot();
}
//===-------------------------------------------------------------------===//
// Binding values to regions.
//===-------------------------------------------------------------------===//
Store InvalidateRegion(Store store, const MemRegion *R, const Expr *E,
unsigned Count, InvalidatedSymbols *IS) {
return RegionStoreManager::InvalidateRegions(store, &R, &R+1, E, Count, IS);
}
Store InvalidateRegions(Store store,
const MemRegion * const *Begin,
const MemRegion * const *End,
const Expr *E, unsigned Count,
InvalidatedSymbols *IS);
public: // Made public for helper classes.
void RemoveSubRegionBindings(RegionBindings &B, const MemRegion *R,
RegionStoreSubRegionMap &M);
RegionBindings Add(RegionBindings B, BindingKey K, SVal V);
RegionBindings Add(RegionBindings B, const MemRegion *R,
BindingKey::Kind k, SVal V);
const SVal *Lookup(RegionBindings B, BindingKey K);
const SVal *Lookup(RegionBindings B, const MemRegion *R, BindingKey::Kind k);
RegionBindings Remove(RegionBindings B, BindingKey K);
RegionBindings Remove(RegionBindings B, const MemRegion *R,
BindingKey::Kind k);
RegionBindings Remove(RegionBindings B, const MemRegion *R) {
return Remove(Remove(B, R, BindingKey::Direct), R, BindingKey::Default);
}
Store Remove(Store store, BindingKey K);
public: // Part of public interface to class.
Store Bind(Store store, Loc LV, SVal V);
Store BindCompoundLiteral(Store store, const CompoundLiteralExpr* CL,
const LocationContext *LC, SVal V);
Store BindDecl(Store store, const VarRegion *VR, SVal InitVal);
Store BindDeclWithNoInit(Store store, const VarRegion *) {
return store;
}
/// BindStruct - Bind a compound value to a structure.
Store BindStruct(Store store, const TypedRegion* R, SVal V);
Store BindArray(Store store, const TypedRegion* R, SVal V);
/// KillStruct - Set the entire struct to unknown.
Store KillStruct(Store store, const TypedRegion* R);
Store Remove(Store store, Loc LV);
//===------------------------------------------------------------------===//
// Loading values from regions.
//===------------------------------------------------------------------===//
/// The high level logic for this method is this:
/// Retrieve (L)
/// if L has binding
/// return L's binding
/// else if L is in killset
/// return unknown
/// else
/// if L is on stack or heap
/// return undefined
/// else
/// return symbolic
SVal Retrieve(Store store, Loc L, QualType T = QualType());
SVal RetrieveElement(Store store, const ElementRegion *R);
SVal RetrieveField(Store store, const FieldRegion *R);
SVal RetrieveObjCIvar(Store store, const ObjCIvarRegion *R);
SVal RetrieveVar(Store store, const VarRegion *R);
SVal RetrieveLazySymbol(const TypedRegion *R);
SVal RetrieveFieldOrElementCommon(Store store, const TypedRegion *R,
QualType Ty, const MemRegion *superR);
/// Retrieve the values in a struct and return a CompoundVal, used when doing
/// struct copy:
/// struct s x, y;
/// x = y;
/// y's value is retrieved by this method.
SVal RetrieveStruct(Store store, const TypedRegion* R);
SVal RetrieveArray(Store store, const TypedRegion* R);
/// Get the state and region whose binding this region R corresponds to.
std::pair<Store, const MemRegion*>
GetLazyBinding(RegionBindings B, const MemRegion *R);
Store CopyLazyBindings(nonloc::LazyCompoundVal V, Store store,
const TypedRegion *R);
const ElementRegion *GetElementZeroRegion(const MemRegion *R, QualType T);
//===------------------------------------------------------------------===//
// State pruning.
//===------------------------------------------------------------------===//
/// RemoveDeadBindings - Scans the RegionStore of 'state' for dead values.
/// It returns a new Store with these values removed.
Store RemoveDeadBindings(Store store, Stmt* Loc, SymbolReaper& SymReaper,
llvm::SmallVectorImpl<const MemRegion*>& RegionRoots);
const GRState *EnterStackFrame(const GRState *state,
const StackFrameContext *frame);
//===------------------------------------------------------------------===//
// Region "extents".
//===------------------------------------------------------------------===//
const GRState *setExtent(const GRState *state,const MemRegion* R,SVal Extent);
DefinedOrUnknownSVal getSizeInElements(const GRState *state,
const MemRegion* R, QualType EleTy);
//===------------------------------------------------------------------===//
// Utility methods.
//===------------------------------------------------------------------===//
static inline RegionBindings GetRegionBindings(Store store) {
return RegionBindings(static_cast<const RegionBindings::TreeTy*>(store));
}
void print(Store store, llvm::raw_ostream& Out, const char* nl,
const char *sep);
void iterBindings(Store store, BindingsHandler& f) {
// FIXME: Implement.
}
// FIXME: Remove.
BasicValueFactory& getBasicVals() {
return StateMgr.getBasicVals();
}
// FIXME: Remove.
ASTContext& getContext() { return StateMgr.getContext(); }
};
} // end anonymous namespace
//===----------------------------------------------------------------------===//
// RegionStore creation.
//===----------------------------------------------------------------------===//
StoreManager *clang::CreateRegionStoreManager(GRStateManager& StMgr) {
RegionStoreFeatures F = maximal_features_tag();
return new RegionStoreManager(StMgr, F);
}
StoreManager *clang::CreateFieldsOnlyRegionStoreManager(GRStateManager &StMgr) {
RegionStoreFeatures F = minimal_features_tag();
F.enableFields(true);
return new RegionStoreManager(StMgr, F);
}
void
RegionStoreSubRegionMap::process(llvm::SmallVectorImpl<const SubRegion*> &WL,
const SubRegion *R) {
const MemRegion *superR = R->getSuperRegion();
if (add(superR, R))
if (const SubRegion *sr = dyn_cast<SubRegion>(superR))
WL.push_back(sr);
}
RegionStoreSubRegionMap*
RegionStoreManager::getRegionStoreSubRegionMap(Store store) {
RegionBindings B = GetRegionBindings(store);
RegionStoreSubRegionMap *M = new RegionStoreSubRegionMap();
llvm::SmallVector<const SubRegion*, 10> WL;
for (RegionBindings::iterator I=B.begin(), E=B.end(); I!=E; ++I)
if (const SubRegion *R = dyn_cast<SubRegion>(I.getKey().getRegion()))
M->process(WL, R);
// We also need to record in the subregion map "intermediate" regions that
// don't have direct bindings but are super regions of those that do.
while (!WL.empty()) {
const SubRegion *R = WL.back();
WL.pop_back();
M->process(WL, R);
}
return M;
}
//===----------------------------------------------------------------------===//
// Binding invalidation.
//===----------------------------------------------------------------------===//
void RegionStoreManager::RemoveSubRegionBindings(RegionBindings &B,
const MemRegion *R,
RegionStoreSubRegionMap &M) {
if (const RegionStoreSubRegionMap::Set *S = M.getSubRegions(R))
for (RegionStoreSubRegionMap::Set::iterator I = S->begin(), E = S->end();
I != E; ++I)
RemoveSubRegionBindings(B, *I, M);
B = Remove(B, R);
}
namespace {
class InvalidateRegionsWorker {
typedef BumpVector<BindingKey> RegionCluster;
typedef llvm::DenseMap<const MemRegion *, RegionCluster *> ClusterMap;
typedef llvm::SmallVector<std::pair<const MemRegion *,RegionCluster*>, 10>
WorkList;
BumpVectorContext BVC;
ClusterMap ClusterM;
WorkList WL;
public:
Store InvalidateRegions(RegionStoreManager &RM, Store store,
const MemRegion * const *I,const MemRegion * const *E,
const Expr *Ex, unsigned Count,
StoreManager::InvalidatedSymbols *IS,
ASTContext &Ctx, ValueManager &ValMgr);
private:
void AddToWorkList(BindingKey K);
void AddToWorkList(const MemRegion *R);
void AddToCluster(BindingKey K);
RegionCluster **getCluster(const MemRegion *R);
};
}
void InvalidateRegionsWorker::AddToCluster(BindingKey K) {
const MemRegion *R = K.getRegion();
const MemRegion *baseR = R->getBaseRegion();
RegionCluster **CPtr = getCluster(baseR);
assert(*CPtr);
(*CPtr)->push_back(K, BVC);
}
void InvalidateRegionsWorker::AddToWorkList(BindingKey K) {
AddToWorkList(K.getRegion());
}
void InvalidateRegionsWorker::AddToWorkList(const MemRegion *R) {
const MemRegion *baseR = R->getBaseRegion();
RegionCluster **CPtr = getCluster(baseR);
if (RegionCluster *C = *CPtr) {
WL.push_back(std::make_pair(baseR, C));
*CPtr = NULL;
}
}
InvalidateRegionsWorker::RegionCluster **
InvalidateRegionsWorker::getCluster(const MemRegion *R) {
RegionCluster *&CRef = ClusterM[R];
if (!CRef) {
void *Mem = BVC.getAllocator().Allocate<RegionCluster>();
CRef = new (Mem) RegionCluster(BVC, 10);
}
return &CRef;
}
Store InvalidateRegionsWorker::InvalidateRegions(RegionStoreManager &RM,
Store store,
const MemRegion * const *I,
const MemRegion * const *E,
const Expr *Ex, unsigned Count,
StoreManager::InvalidatedSymbols *IS,
ASTContext &Ctx,
ValueManager &ValMgr) {
RegionBindings B = RegionStoreManager::GetRegionBindings(store);
// Scan the entire store and make the region clusters.
for (RegionBindings::iterator RI = B.begin(), RE = B.end(); RI != RE; ++RI) {
AddToCluster(RI.getKey());
if (const MemRegion *R = RI.getData().getAsRegion()) {
// Generate a cluster, but don't add the region to the cluster
// if there aren't any bindings.
getCluster(R->getBaseRegion());
}
}
// Add the cluster for I .. E to a worklist.
for ( ; I != E; ++I)
AddToWorkList(*I);
while (!WL.empty()) {
const MemRegion *baseR;
RegionCluster *C;
llvm::tie(baseR, C) = WL.back();
WL.pop_back();
for (RegionCluster::iterator I = C->begin(), E = C->end(); I != E; ++I) {
BindingKey K = *I;
// Get the old binding. Is it a region? If so, add it to the worklist.
if (const SVal *V = RM.Lookup(B, K)) {
if (const MemRegion *R = V->getAsRegion())
AddToWorkList(R);
// A symbol? Mark it touched by the invalidation.
if (IS)
if (SymbolRef Sym = V->getAsSymbol())
IS->insert(Sym);
}
B = RM.Remove(B, K);
}
// Now inspect the base region.
if (IS) {
// Symbolic region? Mark that symbol touched by the invalidation.
if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(baseR))
IS->insert(SR->getSymbol());
}
// BlockDataRegion? If so, invalidate captured variables that are passed
// by reference.
if (const BlockDataRegion *BR = dyn_cast<BlockDataRegion>(baseR)) {
for (BlockDataRegion::referenced_vars_iterator
BI = BR->referenced_vars_begin(), BE = BR->referenced_vars_end() ;
BI != BE; ++BI) {
const VarRegion *VR = *BI;
const VarDecl *VD = VR->getDecl();
if (VD->getAttr<BlocksAttr>() || !VD->hasLocalStorage())
AddToWorkList(VR);
}
continue;
}
if (isa<AllocaRegion>(baseR) || isa<SymbolicRegion>(baseR)) {
// Invalidate the region by setting its default value to
// conjured symbol. The type of the symbol is irrelavant.
DefinedOrUnknownSVal V = ValMgr.getConjuredSymbolVal(baseR, Ex, Ctx.IntTy,
Count);
B = RM.Add(B, baseR, BindingKey::Default, V);
continue;
}
if (!baseR->isBoundable())
continue;
const TypedRegion *TR = cast<TypedRegion>(baseR);
QualType T = TR->getValueType(Ctx);
// Invalidate the binding.
if (const RecordType *RT = T->getAsStructureType()) {
const RecordDecl *RD = RT->getDecl()->getDefinition();
// No record definition. There is nothing we can do.
if (!RD) {
B = RM.Remove(B, baseR);
continue;
}
// Invalidate the region by setting its default value to
// conjured symbol. The type of the symbol is irrelavant.
DefinedOrUnknownSVal V = ValMgr.getConjuredSymbolVal(baseR, Ex, Ctx.IntTy,
Count);
B = RM.Add(B, baseR, BindingKey::Default, V);
continue;
}
if (const ArrayType *AT = Ctx.getAsArrayType(T)) {
// Set the default value of the array to conjured symbol.
DefinedOrUnknownSVal V =
ValMgr.getConjuredSymbolVal(baseR, Ex, AT->getElementType(), Count);
B = RM.Add(B, baseR, BindingKey::Default, V);
continue;
}
DefinedOrUnknownSVal V = ValMgr.getConjuredSymbolVal(baseR, Ex, T, Count);
assert(SymbolManager::canSymbolicate(T) || V.isUnknown());
B = RM.Add(B, baseR, BindingKey::Direct, V);
}
// Create a new state with the updated bindings.
return B.getRoot();
}
Store RegionStoreManager::InvalidateRegions(Store store,
const MemRegion * const *I,
const MemRegion * const *E,
const Expr *Ex, unsigned Count,
InvalidatedSymbols *IS) {
InvalidateRegionsWorker W;
return W.InvalidateRegions(*this, store, I, E, Ex, Count, IS, getContext(),
StateMgr.getValueManager());
}
//===----------------------------------------------------------------------===//
// Extents for regions.
//===----------------------------------------------------------------------===//
DefinedOrUnknownSVal RegionStoreManager::getSizeInElements(const GRState *state,
const MemRegion *R,
QualType EleTy) {
switch (R->getKind()) {
case MemRegion::CXXThisRegionKind:
assert(0 && "Cannot get size of 'this' region");
case MemRegion::GenericMemSpaceRegionKind:
case MemRegion::StackLocalsSpaceRegionKind:
case MemRegion::StackArgumentsSpaceRegionKind:
case MemRegion::HeapSpaceRegionKind:
case MemRegion::GlobalsSpaceRegionKind:
case MemRegion::UnknownSpaceRegionKind:
assert(0 && "Cannot index into a MemSpace");
return UnknownVal();
case MemRegion::FunctionTextRegionKind:
case MemRegion::BlockTextRegionKind:
case MemRegion::BlockDataRegionKind:
// Technically this can happen if people do funny things with casts.
return UnknownVal();
// Not yet handled.
case MemRegion::AllocaRegionKind:
case MemRegion::CompoundLiteralRegionKind:
case MemRegion::ElementRegionKind:
case MemRegion::FieldRegionKind:
case MemRegion::ObjCIvarRegionKind:
case MemRegion::CXXObjectRegionKind:
return UnknownVal();
case MemRegion::SymbolicRegionKind: {
const SVal *Size = state->get<RegionExtents>(R);
if (!Size)
return UnknownVal();
const nonloc::ConcreteInt *CI = dyn_cast<nonloc::ConcreteInt>(Size);
if (!CI)
return UnknownVal();
CharUnits RegionSize =
CharUnits::fromQuantity(CI->getValue().getSExtValue());
CharUnits EleSize = getContext().getTypeSizeInChars(EleTy);
assert(RegionSize % EleSize == 0);
return ValMgr.makeIntVal(RegionSize / EleSize, false);
}
case MemRegion::StringRegionKind: {
const StringLiteral* Str = cast<StringRegion>(R)->getStringLiteral();
// We intentionally made the size value signed because it participates in
// operations with signed indices.
return ValMgr.makeIntVal(Str->getByteLength()+1, false);
}
case MemRegion::VarRegionKind: {
const VarRegion* VR = cast<VarRegion>(R);
// Get the type of the variable.
QualType T = VR->getDesugaredValueType(getContext());
// FIXME: Handle variable-length arrays.
if (isa<VariableArrayType>(T))
return UnknownVal();
if (const ConstantArrayType* CAT = dyn_cast<ConstantArrayType>(T)) {
// return the size as signed integer.
return ValMgr.makeIntVal(CAT->getSize(), false);
}
// Clients can use ordinary variables as if they were arrays. These
// essentially are arrays of size 1.
return ValMgr.makeIntVal(1, false);
}
}
assert(0 && "Unreachable");
return UnknownVal();
}
const GRState *RegionStoreManager::setExtent(const GRState *state,
const MemRegion *region,
SVal extent) {
return state->set<RegionExtents>(region, extent);
}
//===----------------------------------------------------------------------===//
// Location and region casting.
//===----------------------------------------------------------------------===//
/// ArrayToPointer - Emulates the "decay" of an array to a pointer
/// type. 'Array' represents the lvalue of the array being decayed
/// to a pointer, and the returned SVal represents the decayed
/// version of that lvalue (i.e., a pointer to the first element of
/// the array). This is called by GRExprEngine when evaluating casts
/// from arrays to pointers.
SVal RegionStoreManager::ArrayToPointer(Loc Array) {
if (!isa<loc::MemRegionVal>(Array))
return UnknownVal();
const MemRegion* R = cast<loc::MemRegionVal>(&Array)->getRegion();
const TypedRegion* ArrayR = dyn_cast<TypedRegion>(R);
if (!ArrayR)
return UnknownVal();
// Strip off typedefs from the ArrayRegion's ValueType.
QualType T = ArrayR->getValueType(getContext()).getDesugaredType();
ArrayType *AT = cast<ArrayType>(T);
T = AT->getElementType();
SVal ZeroIdx = ValMgr.makeZeroArrayIndex();
return loc::MemRegionVal(MRMgr.getElementRegion(T, ZeroIdx, ArrayR,
getContext()));
}
//===----------------------------------------------------------------------===//
// Pointer arithmetic.
//===----------------------------------------------------------------------===//
SVal RegionStoreManager::EvalBinOp(BinaryOperator::Opcode Op, Loc L, NonLoc R,
QualType resultTy) {
// Assume the base location is MemRegionVal.
if (!isa<loc::MemRegionVal>(L))
return UnknownVal();
const MemRegion* MR = cast<loc::MemRegionVal>(L).getRegion();
const ElementRegion *ER = 0;
switch (MR->getKind()) {
case MemRegion::SymbolicRegionKind: {
const SymbolicRegion *SR = cast<SymbolicRegion>(MR);
SymbolRef Sym = SR->getSymbol();
QualType T = Sym->getType(getContext());
QualType EleTy;
if (const PointerType *PT = T->getAs<PointerType>())
EleTy = PT->getPointeeType();
else
EleTy = T->getAs<ObjCObjectPointerType>()->getPointeeType();
SVal ZeroIdx = ValMgr.makeZeroArrayIndex();
ER = MRMgr.getElementRegion(EleTy, ZeroIdx, SR, getContext());
break;
}
case MemRegion::AllocaRegionKind: {
const AllocaRegion *AR = cast<AllocaRegion>(MR);
QualType T = getContext().CharTy; // Create an ElementRegion of bytes.
QualType EleTy = T->getAs<PointerType>()->getPointeeType();
SVal ZeroIdx = ValMgr.makeZeroArrayIndex();
ER = MRMgr.getElementRegion(EleTy, ZeroIdx, AR, getContext());
break;
}
case MemRegion::ElementRegionKind: {
ER = cast<ElementRegion>(MR);
break;
}
// Not yet handled.
case MemRegion::VarRegionKind:
case MemRegion::StringRegionKind: {
}
// Fall-through.
case MemRegion::CompoundLiteralRegionKind:
case MemRegion::FieldRegionKind:
case MemRegion::ObjCIvarRegionKind:
case MemRegion::CXXObjectRegionKind:
return UnknownVal();
case MemRegion::FunctionTextRegionKind:
case MemRegion::BlockTextRegionKind:
case MemRegion::BlockDataRegionKind:
// Technically this can happen if people do funny things with casts.
return UnknownVal();
case MemRegion::CXXThisRegionKind:
assert(0 &&
"Cannot perform pointer arithmetic on implicit argument 'this'");
case MemRegion::GenericMemSpaceRegionKind:
case MemRegion::StackLocalsSpaceRegionKind:
case MemRegion::StackArgumentsSpaceRegionKind:
case MemRegion::HeapSpaceRegionKind:
case MemRegion::GlobalsSpaceRegionKind:
case MemRegion::UnknownSpaceRegionKind:
assert(0 && "Cannot perform pointer arithmetic on a MemSpace");
return UnknownVal();
}
SVal Idx = ER->getIndex();
nonloc::ConcreteInt* Base = dyn_cast<nonloc::ConcreteInt>(&Idx);
// For now, only support:
// (a) concrete integer indices that can easily be resolved
// (b) 0 + symbolic index
if (Base) {
if (nonloc::ConcreteInt *Offset = dyn_cast<nonloc::ConcreteInt>(&R)) {
// FIXME: Should use SValuator here.
SVal NewIdx =
Base->evalBinOp(ValMgr, Op,
cast<nonloc::ConcreteInt>(ValMgr.convertToArrayIndex(*Offset)));
const MemRegion* NewER =
MRMgr.getElementRegion(ER->getElementType(), NewIdx,
ER->getSuperRegion(), getContext());
return ValMgr.makeLoc(NewER);
}
if (0 == Base->getValue()) {
const MemRegion* NewER =
MRMgr.getElementRegion(ER->getElementType(), R,
ER->getSuperRegion(), getContext());
return ValMgr.makeLoc(NewER);
}
}
return UnknownVal();
}
//===----------------------------------------------------------------------===//
// Loading values from regions.
//===----------------------------------------------------------------------===//
Optional<SVal> RegionStoreManager::getDirectBinding(RegionBindings B,
const MemRegion *R) {
if (const SVal *V = Lookup(B, R, BindingKey::Direct))
return *V;
return Optional<SVal>();
}
Optional<SVal> RegionStoreManager::getDefaultBinding(RegionBindings B,
const MemRegion *R) {
if (R->isBoundable())
if (const TypedRegion *TR = dyn_cast<TypedRegion>(R))
if (TR->getValueType(getContext())->isUnionType())
return UnknownVal();
if (const SVal *V = Lookup(B, R, BindingKey::Default))
return *V;
return Optional<SVal>();
}
Optional<SVal> RegionStoreManager::getBinding(RegionBindings B,
const MemRegion *R) {
if (Optional<SVal> V = getDirectBinding(B, R))
return V;
return getDefaultBinding(B, R);
}
static bool IsReinterpreted(QualType RTy, QualType UsedTy, ASTContext &Ctx) {
RTy = Ctx.getCanonicalType(RTy);
UsedTy = Ctx.getCanonicalType(UsedTy);
if (RTy == UsedTy)
return false;
// Recursively check the types. We basically want to see if a pointer value
// is ever reinterpreted as a non-pointer, e.g. void** and intptr_t*
// represents a reinterpretation.
if (Loc::IsLocType(RTy) && Loc::IsLocType(UsedTy)) {
const PointerType *PRTy = RTy->getAs<PointerType>();
const PointerType *PUsedTy = UsedTy->getAs<PointerType>();
return PUsedTy && PRTy &&
IsReinterpreted(PRTy->getPointeeType(),
PUsedTy->getPointeeType(), Ctx);
}
return true;
}
const ElementRegion *
RegionStoreManager::GetElementZeroRegion(const MemRegion *R, QualType T) {
ASTContext &Ctx = getContext();
SVal idx = ValMgr.makeZeroArrayIndex();
assert(!T.isNull());
return MRMgr.getElementRegion(T, idx, R, Ctx);
}
SVal RegionStoreManager::Retrieve(Store store, Loc L, QualType T) {
assert(!isa<UnknownVal>(L) && "location unknown");
assert(!isa<UndefinedVal>(L) && "location undefined");
// FIXME: Is this even possible? Shouldn't this be treated as a null
// dereference at a higher level?
if (isa<loc::ConcreteInt>(L))
return UndefinedVal();
const MemRegion *MR = cast<loc::MemRegionVal>(L).getRegion();
if (isa<AllocaRegion>(MR) || isa<SymbolicRegion>(MR))
MR = GetElementZeroRegion(MR, T);
if (isa<CodeTextRegion>(MR))
return UnknownVal();
// FIXME: Perhaps this method should just take a 'const MemRegion*' argument
// instead of 'Loc', and have the other Loc cases handled at a higher level.
const TypedRegion *R = cast<TypedRegion>(MR);
QualType RTy = R->getValueType(getContext());
// FIXME: We should eventually handle funny addressing. e.g.:
//
// int x = ...;
// int *p = &x;
// char *q = (char*) p;
// char c = *q; // returns the first byte of 'x'.
//
// Such funny addressing will occur due to layering of regions.
#if 0
ASTContext &Ctx = getContext();
if (!T.isNull() && IsReinterpreted(RTy, T, Ctx)) {
SVal ZeroIdx = ValMgr.makeZeroArrayIndex();
R = MRMgr.getElementRegion(T, ZeroIdx, R, Ctx);
RTy = T;
assert(Ctx.getCanonicalType(RTy) ==
Ctx.getCanonicalType(R->getValueType(Ctx)));
}
#endif
if (RTy->isStructureType())
return RetrieveStruct(store, R);
// FIXME: Handle unions.
if (RTy->isUnionType())
return UnknownVal();
if (RTy->isArrayType())
return RetrieveArray(store, R);
// FIXME: handle Vector types.
if (RTy->isVectorType())
return UnknownVal();
if (const FieldRegion* FR = dyn_cast<FieldRegion>(R))
return CastRetrievedVal(RetrieveField(store, FR), FR, T, false);
if (const ElementRegion* ER = dyn_cast<ElementRegion>(R)) {
// FIXME: Here we actually perform an implicit conversion from the loaded
// value to the element type. Eventually we want to compose these values
// more intelligently. For example, an 'element' can encompass multiple
// bound regions (e.g., several bound bytes), or could be a subset of
// a larger value.
return CastRetrievedVal(RetrieveElement(store, ER), ER, T, false);
}
if (const ObjCIvarRegion *IVR = dyn_cast<ObjCIvarRegion>(R)) {
// FIXME: Here we actually perform an implicit conversion from the loaded
// value to the ivar type. What we should model is stores to ivars
// that blow past the extent of the ivar. If the address of the ivar is
// reinterpretted, it is possible we stored a different value that could
// fit within the ivar. Either we need to cast these when storing them
// or reinterpret them lazily (as we do here).
return CastRetrievedVal(RetrieveObjCIvar(store, IVR), IVR, T, false);
}
if (const VarRegion *VR = dyn_cast<VarRegion>(R)) {
// FIXME: Here we actually perform an implicit conversion from the loaded
// value to the variable type. What we should model is stores to variables
// that blow past the extent of the variable. If the address of the
// variable is reinterpretted, it is possible we stored a different value
// that could fit within the variable. Either we need to cast these when
// storing them or reinterpret them lazily (as we do here).
return CastRetrievedVal(RetrieveVar(store, VR), VR, T, false);
}
RegionBindings B = GetRegionBindings(store);
const SVal *V = Lookup(B, R, BindingKey::Direct);
// Check if the region has a binding.
if (V)
return *V;
// The location does not have a bound value. This means that it has
// the value it had upon its creation and/or entry to the analyzed
// function/method. These are either symbolic values or 'undefined'.
if (R->hasStackNonParametersStorage()) {
// All stack variables are considered to have undefined values
// upon creation. All heap allocated blocks are considered to
// have undefined values as well unless they are explicitly bound
// to specific values.
return UndefinedVal();
}
// All other values are symbolic.
return ValMgr.getRegionValueSymbolVal(R, RTy);
}
std::pair<Store, const MemRegion *>
RegionStoreManager::GetLazyBinding(RegionBindings B, const MemRegion *R) {
if (Optional<SVal> OV = getDirectBinding(B, R))
if (const nonloc::LazyCompoundVal *V =
dyn_cast<nonloc::LazyCompoundVal>(OV.getPointer()))
return std::make_pair(V->getStore(), V->getRegion());
if (const ElementRegion *ER = dyn_cast<ElementRegion>(R)) {
const std::pair<Store, const MemRegion *> &X =
GetLazyBinding(B, ER->getSuperRegion());
if (X.second)
return std::make_pair(X.first,
MRMgr.getElementRegionWithSuper(ER, X.second));
}
else if (const FieldRegion *FR = dyn_cast<FieldRegion>(R)) {
const std::pair<Store, const MemRegion *> &X =
GetLazyBinding(B, FR->getSuperRegion());
if (X.second)
return std::make_pair(X.first,
MRMgr.getFieldRegionWithSuper(FR, X.second));
}
// The NULL MemRegion indicates an non-existent lazy binding. A NULL Store is
// possible for a valid lazy binding.
return std::make_pair((Store) 0, (const MemRegion *) 0);
}
SVal RegionStoreManager::RetrieveElement(Store store,
const ElementRegion* R) {
// Check if the region has a binding.
RegionBindings B = GetRegionBindings(store);
if (Optional<SVal> V = getDirectBinding(B, R))
return *V;
const MemRegion* superR = R->getSuperRegion();
// Check if the region is an element region of a string literal.
if (const StringRegion *StrR=dyn_cast<StringRegion>(superR)) {
// FIXME: Handle loads from strings where the literal is treated as
// an integer, e.g., *((unsigned int*)"hello")
ASTContext &Ctx = getContext();
QualType T = Ctx.getAsArrayType(StrR->getValueType(Ctx))->getElementType();
if (T != Ctx.getCanonicalType(R->getElementType()))
return UnknownVal();
const StringLiteral *Str = StrR->getStringLiteral();
SVal Idx = R->getIndex();
if (nonloc::ConcreteInt *CI = dyn_cast<nonloc::ConcreteInt>(&Idx)) {
int64_t i = CI->getValue().getSExtValue();
int64_t byteLength = Str->getByteLength();
if (i > byteLength) {
// Buffer overflow checking in GRExprEngine should handle this case,
// but we shouldn't rely on it to not overflow here if that checking
// is disabled.
return UnknownVal();
}
char c = (i == byteLength) ? '\0' : Str->getStrData()[i];
return ValMgr.makeIntVal(c, T);
}
}
// Check if the immediate super region has a direct binding.
if (Optional<SVal> V = getDirectBinding(B, superR)) {
if (SymbolRef parentSym = V->getAsSymbol())
return ValMgr.getDerivedRegionValueSymbolVal(parentSym, R);
if (V->isUnknownOrUndef())
return *V;
// Handle LazyCompoundVals for the immediate super region. Other cases
// are handled in 'RetrieveFieldOrElementCommon'.
if (const nonloc::LazyCompoundVal *LCV =
dyn_cast<nonloc::LazyCompoundVal>(V)) {
R = MRMgr.getElementRegionWithSuper(R, LCV->getRegion());
return RetrieveElement(LCV->getStore(), R);
}
// Other cases: give up.
return UnknownVal();
}
return RetrieveFieldOrElementCommon(store, R, R->getElementType(), superR);
}
SVal RegionStoreManager::RetrieveField(Store store,
const FieldRegion* R) {
// Check if the region has a binding.
RegionBindings B = GetRegionBindings(store);
if (Optional<SVal> V = getDirectBinding(B, R))
return *V;
QualType Ty = R->getValueType(getContext());
return RetrieveFieldOrElementCommon(store, R, Ty, R->getSuperRegion());
}
SVal RegionStoreManager::RetrieveFieldOrElementCommon(Store store,
const TypedRegion *R,
QualType Ty,
const MemRegion *superR) {
// At this point we have already checked in either RetrieveElement or
// RetrieveField if 'R' has a direct binding.
RegionBindings B = GetRegionBindings(store);
while (superR) {
if (const Optional<SVal> &D = getDefaultBinding(B, superR)) {
if (SymbolRef parentSym = D->getAsSymbol())
return ValMgr.getDerivedRegionValueSymbolVal(parentSym, R);
if (D->isZeroConstant())
return ValMgr.makeZeroVal(Ty);
if (D->isUnknown())
return *D;
assert(0 && "Unknown default value");
}
// If our super region is a field or element itself, walk up the region
// hierarchy to see if there is a default value installed in an ancestor.
if (isa<FieldRegion>(superR) || isa<ElementRegion>(superR)) {
superR = cast<SubRegion>(superR)->getSuperRegion();
continue;
}
break;
}
// Lazy binding?
Store lazyBindingStore = NULL;
const MemRegion *lazyBindingRegion = NULL;
llvm::tie(lazyBindingStore, lazyBindingRegion) = GetLazyBinding(B, R);
if (lazyBindingRegion) {
if (const ElementRegion *ER = dyn_cast<ElementRegion>(lazyBindingRegion))
return RetrieveElement(lazyBindingStore, ER);
return RetrieveField(lazyBindingStore,
cast<FieldRegion>(lazyBindingRegion));
}
if (R->hasStackNonParametersStorage()) {
if (isa<ElementRegion>(R)) {
// Currently we don't reason specially about Clang-style vectors. Check
// if superR is a vector and if so return Unknown.
if (const TypedRegion *typedSuperR = dyn_cast<TypedRegion>(superR)) {
if (typedSuperR->getValueType(getContext())->isVectorType())
return UnknownVal();
}
}
return UndefinedVal();
}
// All other values are symbolic.
return ValMgr.getRegionValueSymbolVal(R, Ty);
}
SVal RegionStoreManager::RetrieveObjCIvar(Store store, const ObjCIvarRegion* R){
// Check if the region has a binding.
RegionBindings B = GetRegionBindings(store);
if (Optional<SVal> V = getDirectBinding(B, R))
return *V;
const MemRegion *superR = R->getSuperRegion();
// Check if the super region has a default binding.
if (Optional<SVal> V = getDefaultBinding(B, superR)) {
if (SymbolRef parentSym = V->getAsSymbol())
return ValMgr.getDerivedRegionValueSymbolVal(parentSym, R);
// Other cases: give up.
return UnknownVal();
}
return RetrieveLazySymbol(R);
}
SVal RegionStoreManager::RetrieveVar(Store store, const VarRegion *R) {
// Check if the region has a binding.
RegionBindings B = GetRegionBindings(store);
if (Optional<SVal> V = getDirectBinding(B, R))
return *V;
// Lazily derive a value for the VarRegion.
const VarDecl *VD = R->getDecl();
QualType T = VD->getType();
const MemSpaceRegion *MS = R->getMemorySpace();
if (isa<UnknownSpaceRegion>(MS) ||
isa<StackArgumentsSpaceRegion>(MS))
return ValMgr.getRegionValueSymbolVal(R, T);
if (isa<GlobalsSpaceRegion>(MS)) {
if (VD->isFileVarDecl())
return ValMgr.getRegionValueSymbolVal(R, T);
if (T->isIntegerType())
return ValMgr.makeIntVal(0, T);
if (T->isPointerType())
return ValMgr.makeNull();
return UnknownVal();
}
return UndefinedVal();
}
SVal RegionStoreManager::RetrieveLazySymbol(const TypedRegion *R) {
QualType valTy = R->getValueType(getContext());
// All other values are symbolic.
return ValMgr.getRegionValueSymbolVal(R, valTy);
}
SVal RegionStoreManager::RetrieveStruct(Store store, const TypedRegion* R) {
QualType T = R->getValueType(getContext());
assert(T->isStructureType());
const RecordType* RT = T->getAsStructureType();
RecordDecl* RD = RT->getDecl();
assert(RD->isDefinition());
(void)RD;
#if USE_EXPLICIT_COMPOUND
llvm::ImmutableList<SVal> StructVal = getBasicVals().getEmptySValList();
// FIXME: We shouldn't use a std::vector. If RecordDecl doesn't have a
// reverse iterator, we should implement one.
std::vector<FieldDecl *> Fields(RD->field_begin(), RD->field_end());
for (std::vector<FieldDecl *>::reverse_iterator Field = Fields.rbegin(),
FieldEnd = Fields.rend();
Field != FieldEnd; ++Field) {
FieldRegion* FR = MRMgr.getFieldRegion(*Field, R);
QualType FTy = (*Field)->getType();
SVal FieldValue = Retrieve(store, loc::MemRegionVal(FR), FTy).getSVal();
StructVal = getBasicVals().consVals(FieldValue, StructVal);
}
return ValMgr.makeCompoundVal(T, StructVal);
#else
return ValMgr.makeLazyCompoundVal(store, R);
#endif
}
SVal RegionStoreManager::RetrieveArray(Store store, const TypedRegion * R) {
#if USE_EXPLICIT_COMPOUND
QualType T = R->getValueType(getContext());
ConstantArrayType* CAT = cast<ConstantArrayType>(T.getTypePtr());
llvm::ImmutableList<SVal> ArrayVal = getBasicVals().getEmptySValList();
uint64_t size = CAT->getSize().getZExtValue();
for (uint64_t i = 0; i < size; ++i) {
SVal Idx = ValMgr.makeArrayIndex(i);
ElementRegion* ER = MRMgr.getElementRegion(CAT->getElementType(), Idx, R,
getContext());
QualType ETy = ER->getElementType();
SVal ElementVal = Retrieve(store, loc::MemRegionVal(ER), ETy).getSVal();
ArrayVal = getBasicVals().consVals(ElementVal, ArrayVal);
}
return ValMgr.makeCompoundVal(T, ArrayVal);
#else
assert(isa<ConstantArrayType>(R->getValueType(getContext())));
return ValMgr.makeLazyCompoundVal(store, R);
#endif
}
//===----------------------------------------------------------------------===//
// Binding values to regions.
//===----------------------------------------------------------------------===//
Store RegionStoreManager::Remove(Store store, Loc L) {
if (isa<loc::MemRegionVal>(L))
if (const MemRegion* R = cast<loc::MemRegionVal>(L).getRegion())
return Remove(GetRegionBindings(store), R).getRoot();
return store;
}
Store RegionStoreManager::Bind(Store store, Loc L, SVal V) {
if (isa<loc::ConcreteInt>(L))
return store;
// If we get here, the location should be a region.
const MemRegion *R = cast<loc::MemRegionVal>(L).getRegion();
// Check if the region is a struct region.
if (const TypedRegion* TR = dyn_cast<TypedRegion>(R))
if (TR->getValueType(getContext())->isStructureType())
return BindStruct(store, TR, V);
// Special case: the current region represents a cast and it and the super
// region both have pointer types or intptr_t types. If so, perform the
// bind to the super region.
// This is needed to support OSAtomicCompareAndSwap and friends or other
// loads that treat integers as pointers and vis versa.
if (const ElementRegion *ER = dyn_cast<ElementRegion>(R)) {
if (ER->getIndex().isZeroConstant()) {
if (const TypedRegion *superR =
dyn_cast<TypedRegion>(ER->getSuperRegion())) {
ASTContext &Ctx = getContext();
QualType superTy = superR->getValueType(Ctx);
QualType erTy = ER->getValueType(Ctx);
if (IsAnyPointerOrIntptr(superTy, Ctx) &&
IsAnyPointerOrIntptr(erTy, Ctx)) {
V = ValMgr.getSValuator().EvalCast(V, superTy, erTy);
return Bind(store, loc::MemRegionVal(superR), V);
}
// For now, just invalidate the fields of the struct/union/class.
// FIXME: Precisely handle the fields of the record.
if (superTy->isRecordType())
return InvalidateRegion(store, superR, NULL, 0, NULL);
}
}
}
else if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R)) {
// Binding directly to a symbolic region should be treated as binding
// to element 0.
QualType T = SR->getSymbol()->getType(getContext());
// FIXME: Is this the right way to handle symbols that are references?
if (const PointerType *PT = T->getAs<PointerType>())
T = PT->getPointeeType();
else
T = T->getAs<ReferenceType>()->getPointeeType();
R = GetElementZeroRegion(SR, T);
}
// Perform the binding.
RegionBindings B = GetRegionBindings(store);
return Add(B, R, BindingKey::Direct, V).getRoot();
}
Store RegionStoreManager::BindDecl(Store store, const VarRegion *VR,
SVal InitVal) {
QualType T = VR->getDecl()->getType();
if (T->isArrayType())
return BindArray(store, VR, InitVal);
if (T->isStructureType())
return BindStruct(store, VR, InitVal);
return Bind(store, ValMgr.makeLoc(VR), InitVal);
}
// FIXME: this method should be merged into Bind().
Store RegionStoreManager::BindCompoundLiteral(Store store,
const CompoundLiteralExpr *CL,
const LocationContext *LC,
SVal V) {
return Bind(store, loc::MemRegionVal(MRMgr.getCompoundLiteralRegion(CL, LC)),
V);
}
Store RegionStoreManager::setImplicitDefaultValue(Store store,
const MemRegion *R,
QualType T) {
RegionBindings B = GetRegionBindings(store);
SVal V;
if (Loc::IsLocType(T))
V = ValMgr.makeNull();
else if (T->isIntegerType())
V = ValMgr.makeZeroVal(T);
else if (T->isStructureType() || T->isArrayType()) {
// Set the default value to a zero constant when it is a structure
// or array. The type doesn't really matter.
V = ValMgr.makeZeroVal(ValMgr.getContext().IntTy);
}
else {
return store;
}
return Add(B, R, BindingKey::Default, V).getRoot();
}
Store RegionStoreManager::BindArray(Store store, const TypedRegion* R,
SVal Init) {
ASTContext &Ctx = getContext();
const ArrayType *AT =
cast<ArrayType>(Ctx.getCanonicalType(R->getValueType(Ctx)));
QualType ElementTy = AT->getElementType();
Optional<uint64_t> Size;
if (const ConstantArrayType* CAT = dyn_cast<ConstantArrayType>(AT))
Size = CAT->getSize().getZExtValue();
// Check if the init expr is a StringLiteral.
if (isa<loc::MemRegionVal>(Init)) {
const MemRegion* InitR = cast<loc::MemRegionVal>(Init).getRegion();
const StringLiteral* S = cast<StringRegion>(InitR)->getStringLiteral();
const char* str = S->getStrData();
unsigned len = S->getByteLength();
unsigned j = 0;
// Copy bytes from the string literal into the target array. Trailing bytes
// in the array that are not covered by the string literal are initialized
// to zero.
// We assume that string constants are bound to
// constant arrays.
uint64_t size = Size.getValue();
for (uint64_t i = 0; i < size; ++i, ++j) {
if (j >= len)
break;
SVal Idx = ValMgr.makeArrayIndex(i);
const ElementRegion* ER = MRMgr.getElementRegion(ElementTy, Idx, R,
getContext());
SVal V = ValMgr.makeIntVal(str[j], sizeof(char)*8, true);
store = Bind(store, loc::MemRegionVal(ER), V);
}
return store;
}
// Handle lazy compound values.
if (nonloc::LazyCompoundVal *LCV = dyn_cast<nonloc::LazyCompoundVal>(&Init))
return CopyLazyBindings(*LCV, store, R);
// Remaining case: explicit compound values.
if (Init.isUnknown())
return setImplicitDefaultValue(store, R, ElementTy);
nonloc::CompoundVal& CV = cast<nonloc::CompoundVal>(Init);
nonloc::CompoundVal::iterator VI = CV.begin(), VE = CV.end();
uint64_t i = 0;
for (; Size.hasValue() ? i < Size.getValue() : true ; ++i, ++VI) {
// The init list might be shorter than the array length.
if (VI == VE)
break;
SVal Idx = ValMgr.makeArrayIndex(i);
const ElementRegion *ER = MRMgr.getElementRegion(ElementTy, Idx, R, getContext());
if (ElementTy->isStructureType())
store = BindStruct(store, ER, *VI);
else
store = Bind(store, ValMgr.makeLoc(ER), *VI);
}
// If the init list is shorter than the array length, set the
// array default value.
if (Size.hasValue() && i < Size.getValue())
store = setImplicitDefaultValue(store, R, ElementTy);
return store;
}
Store RegionStoreManager::BindStruct(Store store, const TypedRegion* R,
SVal V) {
if (!Features.supportsFields())
return store;
QualType T = R->getValueType(getContext());
assert(T->isStructureType());
const RecordType* RT = T->getAs<RecordType>();
RecordDecl* RD = RT->getDecl();
if (!RD->isDefinition())
return store;
// Handle lazy compound values.
if (const nonloc::LazyCompoundVal *LCV=dyn_cast<nonloc::LazyCompoundVal>(&V))
return CopyLazyBindings(*LCV, store, R);
// We may get non-CompoundVal accidentally due to imprecise cast logic.
// Ignore them and kill the field values.
if (V.isUnknown() || !isa<nonloc::CompoundVal>(V))
return KillStruct(store, R);
nonloc::CompoundVal& CV = cast<nonloc::CompoundVal>(V);
nonloc::CompoundVal::iterator VI = CV.begin(), VE = CV.end();
RecordDecl::field_iterator FI, FE;
for (FI = RD->field_begin(), FE = RD->field_end(); FI != FE; ++FI, ++VI) {
if (VI == VE)
break;
QualType FTy = (*FI)->getType();
const FieldRegion* FR = MRMgr.getFieldRegion(*FI, R);
if (FTy->isArrayType())
store = BindArray(store, FR, *VI);
else if (FTy->isStructureType())
store = BindStruct(store, FR, *VI);
else
store = Bind(store, ValMgr.makeLoc(FR), *VI);
}
// There may be fewer values in the initialize list than the fields of struct.
if (FI != FE) {
RegionBindings B = GetRegionBindings(store);
B = Add(B, R, BindingKey::Default, ValMgr.makeIntVal(0, false));
store = B.getRoot();
}
return store;
}
Store RegionStoreManager::KillStruct(Store store, const TypedRegion* R) {
RegionBindings B = GetRegionBindings(store);
llvm::OwningPtr<RegionStoreSubRegionMap>
SubRegions(getRegionStoreSubRegionMap(store));
RemoveSubRegionBindings(B, R, *SubRegions);
// Set the default value of the struct region to "unknown".
return Add(B, R, BindingKey::Default, UnknownVal()).getRoot();
}
Store RegionStoreManager::CopyLazyBindings(nonloc::LazyCompoundVal V,
Store store, const TypedRegion *R) {
// Nuke the old bindings stemming from R.
RegionBindings B = GetRegionBindings(store);
llvm::OwningPtr<RegionStoreSubRegionMap>
SubRegions(getRegionStoreSubRegionMap(store));
// B and DVM are updated after the call to RemoveSubRegionBindings.
RemoveSubRegionBindings(B, R, *SubRegions.get());
// Now copy the bindings. This amounts to just binding 'V' to 'R'. This
// results in a zero-copy algorithm.
return Add(B, R, BindingKey::Direct, V).getRoot();
}
//===----------------------------------------------------------------------===//
// "Raw" retrievals and bindings.
//===----------------------------------------------------------------------===//
BindingKey BindingKey::Make(const MemRegion *R, Kind k) {
if (const ElementRegion *ER = dyn_cast<ElementRegion>(R)) {
const RegionRawOffset &O = ER->getAsRawOffset();
if (O.getRegion())
return BindingKey(O.getRegion(), O.getByteOffset(), k);
// FIXME: There are some ElementRegions for which we cannot compute
// raw offsets yet, including regions with symbolic offsets.
}
return BindingKey(R, 0, k);
}
RegionBindings RegionStoreManager::Add(RegionBindings B, BindingKey K, SVal V) {
return RBFactory.Add(B, K, V);
}
RegionBindings RegionStoreManager::Add(RegionBindings B, const MemRegion *R,
BindingKey::Kind k, SVal V) {
return Add(B, BindingKey::Make(R, k), V);
}
const SVal *RegionStoreManager::Lookup(RegionBindings B, BindingKey K) {
return B.lookup(K);
}
const SVal *RegionStoreManager::Lookup(RegionBindings B,
const MemRegion *R,
BindingKey::Kind k) {
return Lookup(B, BindingKey::Make(R, k));
}
RegionBindings RegionStoreManager::Remove(RegionBindings B, BindingKey K) {
return RBFactory.Remove(B, K);
}
RegionBindings RegionStoreManager::Remove(RegionBindings B, const MemRegion *R,
BindingKey::Kind k){
return Remove(B, BindingKey::Make(R, k));
}
Store RegionStoreManager::Remove(Store store, BindingKey K) {
RegionBindings B = GetRegionBindings(store);
return Remove(B, K).getRoot();
}
//===----------------------------------------------------------------------===//
// State pruning.
//===----------------------------------------------------------------------===//
Store RegionStoreManager::RemoveDeadBindings(Store store, Stmt* Loc,
SymbolReaper& SymReaper,
llvm::SmallVectorImpl<const MemRegion*>& RegionRoots)
{
typedef std::pair<Store, const MemRegion *> RBDNode;
RegionBindings B = GetRegionBindings(store);
// The backmap from regions to subregions.
llvm::OwningPtr<RegionStoreSubRegionMap>
SubRegions(getRegionStoreSubRegionMap(store));
// Do a pass over the regions in the store. For VarRegions we check if
// the variable is still live and if so add it to the list of live roots.
// For other regions we populate our region backmap.
llvm::SmallVector<const MemRegion*, 10> IntermediateRoots;
// Scan the direct bindings for "intermediate" roots.
for (RegionBindings::iterator I = B.begin(), E = B.end(); I != E; ++I) {
const MemRegion *R = I.getKey().getRegion();
IntermediateRoots.push_back(R);
}
// Process the "intermediate" roots to find if they are referenced by
// real roots.
llvm::SmallVector<RBDNode, 10> WorkList;
llvm::SmallVector<RBDNode, 10> Postponed;
llvm::DenseSet<const MemRegion*> IntermediateVisited;
while (!IntermediateRoots.empty()) {
const MemRegion* R = IntermediateRoots.back();
IntermediateRoots.pop_back();
if (IntermediateVisited.count(R))
continue;
IntermediateVisited.insert(R);
if (const VarRegion* VR = dyn_cast<VarRegion>(R)) {
if (SymReaper.isLive(Loc, VR))
WorkList.push_back(std::make_pair(store, VR));
continue;
}
if (const SymbolicRegion* SR = dyn_cast<SymbolicRegion>(R)) {
llvm::SmallVectorImpl<RBDNode> &Q =
SymReaper.isLive(SR->getSymbol()) ? WorkList : Postponed;
Q.push_back(std::make_pair(store, SR));
continue;
}
// Add the super region for R to the worklist if it is a subregion.
if (const SubRegion* superR =
dyn_cast<SubRegion>(cast<SubRegion>(R)->getSuperRegion()))
IntermediateRoots.push_back(superR);
}
// Enqueue the RegionRoots onto WorkList.
for (llvm::SmallVectorImpl<const MemRegion*>::iterator I=RegionRoots.begin(),
E=RegionRoots.end(); I!=E; ++I) {
WorkList.push_back(std::make_pair(store, *I));
}
RegionRoots.clear();
llvm::DenseSet<RBDNode> Visited;
tryAgain:
while (!WorkList.empty()) {
RBDNode N = WorkList.back();
WorkList.pop_back();
// Have we visited this node before?
if (Visited.count(N))
continue;
Visited.insert(N);
const MemRegion *R = N.second;
Store store_N = N.first;
// Enqueue subregions.
RegionStoreSubRegionMap *M;
if (store == store_N)
M = SubRegions.get();
else {
RegionStoreSubRegionMap *& SM = SC[store_N];
if (!SM)
SM = getRegionStoreSubRegionMap(store_N);
M = SM;
}
if (const RegionStoreSubRegionMap::Set *S = M->getSubRegions(R))
for (RegionStoreSubRegionMap::Set::iterator I = S->begin(), E = S->end();
I != E; ++I)
WorkList.push_back(std::make_pair(store_N, *I));
// Enqueue the super region.
if (const SubRegion *SR = dyn_cast<SubRegion>(R)) {
const MemRegion *superR = SR->getSuperRegion();
if (!isa<MemSpaceRegion>(superR)) {
// If 'R' is a field or an element, we want to keep the bindings
// for the other fields and elements around. The reason is that
// pointer arithmetic can get us to the other fields or elements.
assert(isa<FieldRegion>(R) || isa<ElementRegion>(R)
|| isa<ObjCIvarRegion>(R));
WorkList.push_back(std::make_pair(store_N, superR));
}
}
// Mark the symbol for any live SymbolicRegion as "live". This means we
// should continue to track that symbol.
if (const SymbolicRegion *SymR = dyn_cast<SymbolicRegion>(R))
SymReaper.markLive(SymR->getSymbol());
// For BlockDataRegions, enqueue the VarRegions for variables marked
// with __block (passed-by-reference).
// via BlockDeclRefExprs.
if (const BlockDataRegion *BD = dyn_cast<BlockDataRegion>(R)) {
for (BlockDataRegion::referenced_vars_iterator
RI = BD->referenced_vars_begin(), RE = BD->referenced_vars_end();
RI != RE; ++RI) {
if ((*RI)->getDecl()->getAttr<BlocksAttr>())
WorkList.push_back(std::make_pair(store_N, *RI));
}
// No possible data bindings on a BlockDataRegion. Continue to the
// next region in the worklist.
continue;
}
RegionBindings B_N = GetRegionBindings(store_N);
// Get the data binding for R (if any).
Optional<SVal> V = getBinding(B_N, R);
if (V) {
// Check for lazy bindings.
if (const nonloc::LazyCompoundVal *LCV =
dyn_cast<nonloc::LazyCompoundVal>(V.getPointer())) {
const LazyCompoundValData *D = LCV->getCVData();
WorkList.push_back(std::make_pair(D->getStore(), D->getRegion()));
}
else {
// Update the set of live symbols.
for (SVal::symbol_iterator SI=V->symbol_begin(), SE=V->symbol_end();
SI!=SE;++SI)
SymReaper.markLive(*SI);
// If V is a region, then add it to the worklist.
if (const MemRegion *RX = V->getAsRegion())
WorkList.push_back(std::make_pair(store_N, RX));
}
}
}
// See if any postponed SymbolicRegions are actually live now, after
// having done a scan.
for (llvm::SmallVectorImpl<RBDNode>::iterator I = Postponed.begin(),
E = Postponed.end() ; I != E ; ++I) {
if (const SymbolicRegion *SR = cast_or_null<SymbolicRegion>(I->second)) {
if (SymReaper.isLive(SR->getSymbol())) {
WorkList.push_back(*I);
I->second = NULL;
}
}
}
if (!WorkList.empty())
goto tryAgain;
// We have now scanned the store, marking reachable regions and symbols
// as live. We now remove all the regions that are dead from the store
// as well as update DSymbols with the set symbols that are now dead.
Store new_store = store;
for (RegionBindings::iterator I = B.begin(), E = B.end(); I != E; ++I) {
const MemRegion* R = I.getKey().getRegion();
// If this region live? Is so, none of its symbols are dead.
if (Visited.count(std::make_pair(store, R)))
continue;
// Remove this dead region from the store.
new_store = Remove(new_store, I.getKey());
// Mark all non-live symbols that this region references as dead.
if (const SymbolicRegion* SymR = dyn_cast<SymbolicRegion>(R))
SymReaper.maybeDead(SymR->getSymbol());
SVal X = I.getData();
SVal::symbol_iterator SI = X.symbol_begin(), SE = X.symbol_end();
for (; SI != SE; ++SI)
SymReaper.maybeDead(*SI);
}
return new_store;
}
GRState const *RegionStoreManager::EnterStackFrame(GRState const *state,
StackFrameContext const *frame) {
FunctionDecl const *FD = cast<FunctionDecl>(frame->getDecl());
CallExpr const *CE = cast<CallExpr>(frame->getCallSite());
FunctionDecl::param_const_iterator PI = FD->param_begin();
CallExpr::const_arg_iterator AI = CE->arg_begin(), AE = CE->arg_end();
// Copy the arg expression value to the arg variables.
Store store = state->getStore();
for (; AI != AE; ++AI, ++PI) {
SVal ArgVal = state->getSVal(*AI);
store = Bind(store, ValMgr.makeLoc(MRMgr.getVarRegion(*PI, frame)), ArgVal);
}
return state->makeWithStore(store);
}
//===----------------------------------------------------------------------===//
// Utility methods.
//===----------------------------------------------------------------------===//
void RegionStoreManager::print(Store store, llvm::raw_ostream& OS,
const char* nl, const char *sep) {
RegionBindings B = GetRegionBindings(store);
OS << "Store (direct and default bindings):" << nl;
for (RegionBindings::iterator I = B.begin(), E = B.end(); I != E; ++I)
OS << ' ' << I.getKey() << " : " << I.getData() << nl;
}
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