1 //== SymbolManager.h - Management of Symbolic Values ------------*- C++ -*--==//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file defines SymbolManager, a class that manages symbolic values
11 // created for use by ExprEngine and related classes.
13 //===----------------------------------------------------------------------===//
15 #include "clang/StaticAnalyzer/Core/PathSensitive/SymbolManager.h"
16 #include "clang/Analysis/Analyses/LiveVariables.h"
17 #include "clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h"
18 #include "clang/StaticAnalyzer/Core/PathSensitive/Store.h"
19 #include "llvm/Support/raw_ostream.h"
21 using namespace clang;
24 void SymExpr::anchor() { }
26 LLVM_DUMP_METHOD void SymExpr::dump() const {
27 dumpToStream(llvm::errs());
30 void SymIntExpr::dumpToStream(raw_ostream &os) const {
32 getLHS()->dumpToStream(os);
34 << BinaryOperator::getOpcodeStr(getOpcode()) << ' '
35 << getRHS().getZExtValue();
36 if (getRHS().isUnsigned())
40 void IntSymExpr::dumpToStream(raw_ostream &os) const {
41 os << getLHS().getZExtValue();
42 if (getLHS().isUnsigned())
45 << BinaryOperator::getOpcodeStr(getOpcode())
47 getRHS()->dumpToStream(os);
51 void SymSymExpr::dumpToStream(raw_ostream &os) const {
53 getLHS()->dumpToStream(os);
55 << BinaryOperator::getOpcodeStr(getOpcode())
57 getRHS()->dumpToStream(os);
61 void SymbolCast::dumpToStream(raw_ostream &os) const {
62 os << '(' << ToTy.getAsString() << ") (";
63 Operand->dumpToStream(os);
67 void SymbolConjured::dumpToStream(raw_ostream &os) const {
68 os << "conj_$" << getSymbolID() << '{' << T.getAsString() << '}';
71 void SymbolDerived::dumpToStream(raw_ostream &os) const {
72 os << "derived_$" << getSymbolID() << '{'
73 << getParentSymbol() << ',' << getRegion() << '}';
76 void SymbolExtent::dumpToStream(raw_ostream &os) const {
77 os << "extent_$" << getSymbolID() << '{' << getRegion() << '}';
80 void SymbolMetadata::dumpToStream(raw_ostream &os) const {
81 os << "meta_$" << getSymbolID() << '{'
82 << getRegion() << ',' << T.getAsString() << '}';
85 void SymbolData::anchor() { }
87 void SymbolRegionValue::dumpToStream(raw_ostream &os) const {
88 os << "reg_$" << getSymbolID()
89 << '<' << getType().getAsString() << ' ' << R << '>';
92 bool SymExpr::symbol_iterator::operator==(const symbol_iterator &X) const {
96 bool SymExpr::symbol_iterator::operator!=(const symbol_iterator &X) const {
100 SymExpr::symbol_iterator::symbol_iterator(const SymExpr *SE) {
104 SymExpr::symbol_iterator &SymExpr::symbol_iterator::operator++() {
105 assert(!itr.empty() && "attempting to iterate on an 'end' iterator");
110 SymbolRef SymExpr::symbol_iterator::operator*() {
111 assert(!itr.empty() && "attempting to dereference an 'end' iterator");
115 void SymExpr::symbol_iterator::expand() {
116 const SymExpr *SE = itr.pop_back_val();
118 switch (SE->getKind()) {
119 case SymExpr::SymbolRegionValueKind:
120 case SymExpr::SymbolConjuredKind:
121 case SymExpr::SymbolDerivedKind:
122 case SymExpr::SymbolExtentKind:
123 case SymExpr::SymbolMetadataKind:
125 case SymExpr::SymbolCastKind:
126 itr.push_back(cast<SymbolCast>(SE)->getOperand());
128 case SymExpr::SymIntExprKind:
129 itr.push_back(cast<SymIntExpr>(SE)->getLHS());
131 case SymExpr::IntSymExprKind:
132 itr.push_back(cast<IntSymExpr>(SE)->getRHS());
134 case SymExpr::SymSymExprKind: {
135 const SymSymExpr *x = cast<SymSymExpr>(SE);
136 itr.push_back(x->getLHS());
137 itr.push_back(x->getRHS());
141 llvm_unreachable("unhandled expansion case");
144 unsigned SymExpr::computeComplexity() const {
146 for (symbol_iterator I = symbol_begin(), E = symbol_end(); I != E; ++I)
151 const SymbolRegionValue*
152 SymbolManager::getRegionValueSymbol(const TypedValueRegion* R) {
153 llvm::FoldingSetNodeID profile;
154 SymbolRegionValue::Profile(profile, R);
156 SymExpr *SD = DataSet.FindNodeOrInsertPos(profile, InsertPos);
158 SD = (SymExpr*) BPAlloc.Allocate<SymbolRegionValue>();
159 new (SD) SymbolRegionValue(SymbolCounter, R);
160 DataSet.InsertNode(SD, InsertPos);
164 return cast<SymbolRegionValue>(SD);
167 const SymbolConjured* SymbolManager::conjureSymbol(const Stmt *E,
168 const LocationContext *LCtx,
171 const void *SymbolTag) {
172 llvm::FoldingSetNodeID profile;
173 SymbolConjured::Profile(profile, E, T, Count, LCtx, SymbolTag);
175 SymExpr *SD = DataSet.FindNodeOrInsertPos(profile, InsertPos);
177 SD = (SymExpr*) BPAlloc.Allocate<SymbolConjured>();
178 new (SD) SymbolConjured(SymbolCounter, E, LCtx, T, Count, SymbolTag);
179 DataSet.InsertNode(SD, InsertPos);
183 return cast<SymbolConjured>(SD);
187 SymbolManager::getDerivedSymbol(SymbolRef parentSymbol,
188 const TypedValueRegion *R) {
190 llvm::FoldingSetNodeID profile;
191 SymbolDerived::Profile(profile, parentSymbol, R);
193 SymExpr *SD = DataSet.FindNodeOrInsertPos(profile, InsertPos);
195 SD = (SymExpr*) BPAlloc.Allocate<SymbolDerived>();
196 new (SD) SymbolDerived(SymbolCounter, parentSymbol, R);
197 DataSet.InsertNode(SD, InsertPos);
201 return cast<SymbolDerived>(SD);
205 SymbolManager::getExtentSymbol(const SubRegion *R) {
206 llvm::FoldingSetNodeID profile;
207 SymbolExtent::Profile(profile, R);
209 SymExpr *SD = DataSet.FindNodeOrInsertPos(profile, InsertPos);
211 SD = (SymExpr*) BPAlloc.Allocate<SymbolExtent>();
212 new (SD) SymbolExtent(SymbolCounter, R);
213 DataSet.InsertNode(SD, InsertPos);
217 return cast<SymbolExtent>(SD);
220 const SymbolMetadata *
221 SymbolManager::getMetadataSymbol(const MemRegion* R, const Stmt *S, QualType T,
222 const LocationContext *LCtx,
223 unsigned Count, const void *SymbolTag) {
225 llvm::FoldingSetNodeID profile;
226 SymbolMetadata::Profile(profile, R, S, T, LCtx, Count, SymbolTag);
228 SymExpr *SD = DataSet.FindNodeOrInsertPos(profile, InsertPos);
230 SD = (SymExpr*) BPAlloc.Allocate<SymbolMetadata>();
231 new (SD) SymbolMetadata(SymbolCounter, R, S, T, LCtx, Count, SymbolTag);
232 DataSet.InsertNode(SD, InsertPos);
236 return cast<SymbolMetadata>(SD);
240 SymbolManager::getCastSymbol(const SymExpr *Op,
241 QualType From, QualType To) {
242 llvm::FoldingSetNodeID ID;
243 SymbolCast::Profile(ID, Op, From, To);
245 SymExpr *data = DataSet.FindNodeOrInsertPos(ID, InsertPos);
247 data = (SymbolCast*) BPAlloc.Allocate<SymbolCast>();
248 new (data) SymbolCast(Op, From, To);
249 DataSet.InsertNode(data, InsertPos);
252 return cast<SymbolCast>(data);
255 const SymIntExpr *SymbolManager::getSymIntExpr(const SymExpr *lhs,
256 BinaryOperator::Opcode op,
257 const llvm::APSInt& v,
259 llvm::FoldingSetNodeID ID;
260 SymIntExpr::Profile(ID, lhs, op, v, t);
262 SymExpr *data = DataSet.FindNodeOrInsertPos(ID, InsertPos);
265 data = (SymIntExpr*) BPAlloc.Allocate<SymIntExpr>();
266 new (data) SymIntExpr(lhs, op, v, t);
267 DataSet.InsertNode(data, InsertPos);
270 return cast<SymIntExpr>(data);
273 const IntSymExpr *SymbolManager::getIntSymExpr(const llvm::APSInt& lhs,
274 BinaryOperator::Opcode op,
277 llvm::FoldingSetNodeID ID;
278 IntSymExpr::Profile(ID, lhs, op, rhs, t);
280 SymExpr *data = DataSet.FindNodeOrInsertPos(ID, InsertPos);
283 data = (IntSymExpr*) BPAlloc.Allocate<IntSymExpr>();
284 new (data) IntSymExpr(lhs, op, rhs, t);
285 DataSet.InsertNode(data, InsertPos);
288 return cast<IntSymExpr>(data);
291 const SymSymExpr *SymbolManager::getSymSymExpr(const SymExpr *lhs,
292 BinaryOperator::Opcode op,
295 llvm::FoldingSetNodeID ID;
296 SymSymExpr::Profile(ID, lhs, op, rhs, t);
298 SymExpr *data = DataSet.FindNodeOrInsertPos(ID, InsertPos);
301 data = (SymSymExpr*) BPAlloc.Allocate<SymSymExpr>();
302 new (data) SymSymExpr(lhs, op, rhs, t);
303 DataSet.InsertNode(data, InsertPos);
306 return cast<SymSymExpr>(data);
309 QualType SymbolConjured::getType() const {
313 QualType SymbolDerived::getType() const {
314 return R->getValueType();
317 QualType SymbolExtent::getType() const {
318 ASTContext &Ctx = R->getMemRegionManager()->getContext();
319 return Ctx.getSizeType();
322 QualType SymbolMetadata::getType() const {
326 QualType SymbolRegionValue::getType() const {
327 return R->getValueType();
330 SymbolManager::~SymbolManager() {
331 llvm::DeleteContainerSeconds(SymbolDependencies);
334 bool SymbolManager::canSymbolicate(QualType T) {
335 T = T.getCanonicalType();
337 if (Loc::isLocType(T))
340 if (T->isIntegralOrEnumerationType())
343 if (T->isRecordType() && !T->isUnionType())
349 void SymbolManager::addSymbolDependency(const SymbolRef Primary,
350 const SymbolRef Dependent) {
351 SymbolDependTy::iterator I = SymbolDependencies.find(Primary);
352 SymbolRefSmallVectorTy *dependencies = nullptr;
353 if (I == SymbolDependencies.end()) {
354 dependencies = new SymbolRefSmallVectorTy();
355 SymbolDependencies[Primary] = dependencies;
357 dependencies = I->second;
359 dependencies->push_back(Dependent);
362 const SymbolRefSmallVectorTy *SymbolManager::getDependentSymbols(
363 const SymbolRef Primary) {
364 SymbolDependTy::const_iterator I = SymbolDependencies.find(Primary);
365 if (I == SymbolDependencies.end())
370 void SymbolReaper::markDependentsLive(SymbolRef sym) {
371 // Do not mark dependents more then once.
372 SymbolMapTy::iterator LI = TheLiving.find(sym);
373 assert(LI != TheLiving.end() && "The primary symbol is not live.");
374 if (LI->second == HaveMarkedDependents)
376 LI->second = HaveMarkedDependents;
378 if (const SymbolRefSmallVectorTy *Deps = SymMgr.getDependentSymbols(sym)) {
379 for (SymbolRefSmallVectorTy::const_iterator I = Deps->begin(),
380 E = Deps->end(); I != E; ++I) {
381 if (TheLiving.find(*I) != TheLiving.end())
388 void SymbolReaper::markLive(SymbolRef sym) {
389 TheLiving[sym] = NotProcessed;
391 markDependentsLive(sym);
394 void SymbolReaper::markLive(const MemRegion *region) {
395 RegionRoots.insert(region);
396 markElementIndicesLive(region);
399 void SymbolReaper::markElementIndicesLive(const MemRegion *region) {
400 for (auto SR = dyn_cast<SubRegion>(region); SR;
401 SR = dyn_cast<SubRegion>(SR->getSuperRegion())) {
402 if (auto ER = dyn_cast<ElementRegion>(SR)) {
403 SVal Idx = ER->getIndex();
404 for (auto SI = Idx.symbol_begin(), SE = Idx.symbol_end(); SI != SE; ++SI)
410 void SymbolReaper::markInUse(SymbolRef sym) {
411 if (isa<SymbolMetadata>(sym))
412 MetadataInUse.insert(sym);
415 bool SymbolReaper::maybeDead(SymbolRef sym) {
423 bool SymbolReaper::isLiveRegion(const MemRegion *MR) {
424 if (RegionRoots.count(MR))
427 MR = MR->getBaseRegion();
429 if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(MR))
430 return isLive(SR->getSymbol());
432 if (const VarRegion *VR = dyn_cast<VarRegion>(MR))
433 return isLive(VR, true);
435 // FIXME: This is a gross over-approximation. What we really need is a way to
436 // tell if anything still refers to this region. Unlike SymbolicRegions,
437 // AllocaRegions don't have associated symbols, though, so we don't actually
438 // have a way to track their liveness.
439 if (isa<AllocaRegion>(MR))
442 if (isa<CXXThisRegion>(MR))
445 if (isa<MemSpaceRegion>(MR))
448 if (isa<CodeTextRegion>(MR))
454 bool SymbolReaper::isLive(SymbolRef sym) {
455 if (TheLiving.count(sym)) {
456 markDependentsLive(sym);
462 switch (sym->getKind()) {
463 case SymExpr::SymbolRegionValueKind:
464 KnownLive = isLiveRegion(cast<SymbolRegionValue>(sym)->getRegion());
466 case SymExpr::SymbolConjuredKind:
469 case SymExpr::SymbolDerivedKind:
470 KnownLive = isLive(cast<SymbolDerived>(sym)->getParentSymbol());
472 case SymExpr::SymbolExtentKind:
473 KnownLive = isLiveRegion(cast<SymbolExtent>(sym)->getRegion());
475 case SymExpr::SymbolMetadataKind:
476 KnownLive = MetadataInUse.count(sym) &&
477 isLiveRegion(cast<SymbolMetadata>(sym)->getRegion());
479 MetadataInUse.erase(sym);
481 case SymExpr::SymIntExprKind:
482 KnownLive = isLive(cast<SymIntExpr>(sym)->getLHS());
484 case SymExpr::IntSymExprKind:
485 KnownLive = isLive(cast<IntSymExpr>(sym)->getRHS());
487 case SymExpr::SymSymExprKind:
488 KnownLive = isLive(cast<SymSymExpr>(sym)->getLHS()) &&
489 isLive(cast<SymSymExpr>(sym)->getRHS());
491 case SymExpr::SymbolCastKind:
492 KnownLive = isLive(cast<SymbolCast>(sym)->getOperand());
503 SymbolReaper::isLive(const Stmt *ExprVal, const LocationContext *ELCtx) const {
508 // If the reaper's location context is a parent of the expression's
509 // location context, then the expression value is now "out of scope".
510 if (LCtx->isParentOf(ELCtx))
515 // If no statement is provided, everything is this and parent contexts is live.
519 return LCtx->getAnalysis<RelaxedLiveVariables>()->isLive(Loc, ExprVal);
522 bool SymbolReaper::isLive(const VarRegion *VR, bool includeStoreBindings) const{
523 const StackFrameContext *VarContext = VR->getStackFrame();
530 const StackFrameContext *CurrentContext = LCtx->getCurrentStackFrame();
532 if (VarContext == CurrentContext) {
533 // If no statement is provided, everything is live.
537 if (LCtx->getAnalysis<RelaxedLiveVariables>()->isLive(Loc, VR->getDecl()))
540 if (!includeStoreBindings)
543 unsigned &cachedQuery =
544 const_cast<SymbolReaper*>(this)->includedRegionCache[VR];
547 return cachedQuery == 1;
550 // Query the store to see if the region occurs in any live bindings.
551 if (Store store = reapedStore.getStore()) {
553 reapedStore.getStoreManager().includedInBindings(store, VR);
554 cachedQuery = hasRegion ? 1 : 2;
561 return VarContext->isParentOf(CurrentContext);