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 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() << "<" << R << ">";
91 bool SymExpr::symbol_iterator::operator==(const symbol_iterator &X) const {
95 bool SymExpr::symbol_iterator::operator!=(const symbol_iterator &X) const {
99 SymExpr::symbol_iterator::symbol_iterator(const SymExpr *SE) {
103 SymExpr::symbol_iterator &SymExpr::symbol_iterator::operator++() {
104 assert(!itr.empty() && "attempting to iterate on an 'end' iterator");
109 SymbolRef SymExpr::symbol_iterator::operator*() {
110 assert(!itr.empty() && "attempting to dereference an 'end' iterator");
114 void SymExpr::symbol_iterator::expand() {
115 const SymExpr *SE = itr.pop_back_val();
117 switch (SE->getKind()) {
118 case SymExpr::RegionValueKind:
119 case SymExpr::ConjuredKind:
120 case SymExpr::DerivedKind:
121 case SymExpr::ExtentKind:
122 case SymExpr::MetadataKind:
124 case SymExpr::CastSymbolKind:
125 itr.push_back(cast<SymbolCast>(SE)->getOperand());
127 case SymExpr::SymIntKind:
128 itr.push_back(cast<SymIntExpr>(SE)->getLHS());
130 case SymExpr::IntSymKind:
131 itr.push_back(cast<IntSymExpr>(SE)->getRHS());
133 case SymExpr::SymSymKind: {
134 const SymSymExpr *x = cast<SymSymExpr>(SE);
135 itr.push_back(x->getLHS());
136 itr.push_back(x->getRHS());
140 llvm_unreachable("unhandled expansion case");
143 unsigned SymExpr::computeComplexity() const {
145 for (symbol_iterator I = symbol_begin(), E = symbol_end(); I != E; ++I)
150 const SymbolRegionValue*
151 SymbolManager::getRegionValueSymbol(const TypedValueRegion* R) {
152 llvm::FoldingSetNodeID profile;
153 SymbolRegionValue::Profile(profile, R);
155 SymExpr *SD = DataSet.FindNodeOrInsertPos(profile, InsertPos);
157 SD = (SymExpr*) BPAlloc.Allocate<SymbolRegionValue>();
158 new (SD) SymbolRegionValue(SymbolCounter, R);
159 DataSet.InsertNode(SD, InsertPos);
163 return cast<SymbolRegionValue>(SD);
166 const SymbolConjured* SymbolManager::conjureSymbol(const Stmt *E,
167 const LocationContext *LCtx,
170 const void *SymbolTag) {
171 llvm::FoldingSetNodeID profile;
172 SymbolConjured::Profile(profile, E, T, Count, LCtx, SymbolTag);
174 SymExpr *SD = DataSet.FindNodeOrInsertPos(profile, InsertPos);
176 SD = (SymExpr*) BPAlloc.Allocate<SymbolConjured>();
177 new (SD) SymbolConjured(SymbolCounter, E, LCtx, T, Count, SymbolTag);
178 DataSet.InsertNode(SD, InsertPos);
182 return cast<SymbolConjured>(SD);
186 SymbolManager::getDerivedSymbol(SymbolRef parentSymbol,
187 const TypedValueRegion *R) {
189 llvm::FoldingSetNodeID profile;
190 SymbolDerived::Profile(profile, parentSymbol, R);
192 SymExpr *SD = DataSet.FindNodeOrInsertPos(profile, InsertPos);
194 SD = (SymExpr*) BPAlloc.Allocate<SymbolDerived>();
195 new (SD) SymbolDerived(SymbolCounter, parentSymbol, R);
196 DataSet.InsertNode(SD, InsertPos);
200 return cast<SymbolDerived>(SD);
204 SymbolManager::getExtentSymbol(const SubRegion *R) {
205 llvm::FoldingSetNodeID profile;
206 SymbolExtent::Profile(profile, R);
208 SymExpr *SD = DataSet.FindNodeOrInsertPos(profile, InsertPos);
210 SD = (SymExpr*) BPAlloc.Allocate<SymbolExtent>();
211 new (SD) SymbolExtent(SymbolCounter, R);
212 DataSet.InsertNode(SD, InsertPos);
216 return cast<SymbolExtent>(SD);
219 const SymbolMetadata*
220 SymbolManager::getMetadataSymbol(const MemRegion* R, const Stmt *S, QualType T,
221 unsigned Count, const void *SymbolTag) {
223 llvm::FoldingSetNodeID profile;
224 SymbolMetadata::Profile(profile, R, S, T, Count, SymbolTag);
226 SymExpr *SD = DataSet.FindNodeOrInsertPos(profile, InsertPos);
228 SD = (SymExpr*) BPAlloc.Allocate<SymbolMetadata>();
229 new (SD) SymbolMetadata(SymbolCounter, R, S, T, Count, SymbolTag);
230 DataSet.InsertNode(SD, InsertPos);
234 return cast<SymbolMetadata>(SD);
238 SymbolManager::getCastSymbol(const SymExpr *Op,
239 QualType From, QualType To) {
240 llvm::FoldingSetNodeID ID;
241 SymbolCast::Profile(ID, Op, From, To);
243 SymExpr *data = DataSet.FindNodeOrInsertPos(ID, InsertPos);
245 data = (SymbolCast*) BPAlloc.Allocate<SymbolCast>();
246 new (data) SymbolCast(Op, From, To);
247 DataSet.InsertNode(data, InsertPos);
250 return cast<SymbolCast>(data);
253 const SymIntExpr *SymbolManager::getSymIntExpr(const SymExpr *lhs,
254 BinaryOperator::Opcode op,
255 const llvm::APSInt& v,
257 llvm::FoldingSetNodeID ID;
258 SymIntExpr::Profile(ID, lhs, op, v, t);
260 SymExpr *data = DataSet.FindNodeOrInsertPos(ID, InsertPos);
263 data = (SymIntExpr*) BPAlloc.Allocate<SymIntExpr>();
264 new (data) SymIntExpr(lhs, op, v, t);
265 DataSet.InsertNode(data, InsertPos);
268 return cast<SymIntExpr>(data);
271 const IntSymExpr *SymbolManager::getIntSymExpr(const llvm::APSInt& lhs,
272 BinaryOperator::Opcode op,
275 llvm::FoldingSetNodeID ID;
276 IntSymExpr::Profile(ID, lhs, op, rhs, t);
278 SymExpr *data = DataSet.FindNodeOrInsertPos(ID, InsertPos);
281 data = (IntSymExpr*) BPAlloc.Allocate<IntSymExpr>();
282 new (data) IntSymExpr(lhs, op, rhs, t);
283 DataSet.InsertNode(data, InsertPos);
286 return cast<IntSymExpr>(data);
289 const SymSymExpr *SymbolManager::getSymSymExpr(const SymExpr *lhs,
290 BinaryOperator::Opcode op,
293 llvm::FoldingSetNodeID ID;
294 SymSymExpr::Profile(ID, lhs, op, rhs, t);
296 SymExpr *data = DataSet.FindNodeOrInsertPos(ID, InsertPos);
299 data = (SymSymExpr*) BPAlloc.Allocate<SymSymExpr>();
300 new (data) SymSymExpr(lhs, op, rhs, t);
301 DataSet.InsertNode(data, InsertPos);
304 return cast<SymSymExpr>(data);
307 QualType SymbolConjured::getType() const {
311 QualType SymbolDerived::getType() const {
312 return R->getValueType();
315 QualType SymbolExtent::getType() const {
316 ASTContext &Ctx = R->getMemRegionManager()->getContext();
317 return Ctx.getSizeType();
320 QualType SymbolMetadata::getType() const {
324 QualType SymbolRegionValue::getType() const {
325 return R->getValueType();
328 SymbolManager::~SymbolManager() {
329 for (SymbolDependTy::const_iterator I = SymbolDependencies.begin(),
330 E = SymbolDependencies.end(); I != E; ++I) {
336 bool SymbolManager::canSymbolicate(QualType T) {
337 T = T.getCanonicalType();
339 if (Loc::isLocType(T))
342 if (T->isIntegralOrEnumerationType())
345 if (T->isRecordType() && !T->isUnionType())
351 void SymbolManager::addSymbolDependency(const SymbolRef Primary,
352 const SymbolRef Dependent) {
353 SymbolDependTy::iterator I = SymbolDependencies.find(Primary);
354 SymbolRefSmallVectorTy *dependencies = 0;
355 if (I == SymbolDependencies.end()) {
356 dependencies = new SymbolRefSmallVectorTy();
357 SymbolDependencies[Primary] = dependencies;
359 dependencies = I->second;
361 dependencies->push_back(Dependent);
364 const SymbolRefSmallVectorTy *SymbolManager::getDependentSymbols(
365 const SymbolRef Primary) {
366 SymbolDependTy::const_iterator I = SymbolDependencies.find(Primary);
367 if (I == SymbolDependencies.end())
372 void SymbolReaper::markDependentsLive(SymbolRef sym) {
373 // Do not mark dependents more then once.
374 SymbolMapTy::iterator LI = TheLiving.find(sym);
375 assert(LI != TheLiving.end() && "The primary symbol is not live.");
376 if (LI->second == HaveMarkedDependents)
378 LI->second = HaveMarkedDependents;
380 if (const SymbolRefSmallVectorTy *Deps = SymMgr.getDependentSymbols(sym)) {
381 for (SymbolRefSmallVectorTy::const_iterator I = Deps->begin(),
382 E = Deps->end(); I != E; ++I) {
383 if (TheLiving.find(*I) != TheLiving.end())
390 void SymbolReaper::markLive(SymbolRef sym) {
391 TheLiving[sym] = NotProcessed;
393 markDependentsLive(sym);
396 void SymbolReaper::markLive(const MemRegion *region) {
397 RegionRoots.insert(region);
400 void SymbolReaper::markInUse(SymbolRef sym) {
401 if (isa<SymbolMetadata>(sym))
402 MetadataInUse.insert(sym);
405 bool SymbolReaper::maybeDead(SymbolRef sym) {
413 bool SymbolReaper::isLiveRegion(const MemRegion *MR) {
414 if (RegionRoots.count(MR))
417 MR = MR->getBaseRegion();
419 if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(MR))
420 return isLive(SR->getSymbol());
422 if (const VarRegion *VR = dyn_cast<VarRegion>(MR))
423 return isLive(VR, true);
425 // FIXME: This is a gross over-approximation. What we really need is a way to
426 // tell if anything still refers to this region. Unlike SymbolicRegions,
427 // AllocaRegions don't have associated symbols, though, so we don't actually
428 // have a way to track their liveness.
429 if (isa<AllocaRegion>(MR))
432 if (isa<CXXThisRegion>(MR))
435 if (isa<MemSpaceRegion>(MR))
438 if (isa<CodeTextRegion>(MR))
444 bool SymbolReaper::isLive(SymbolRef sym) {
445 if (TheLiving.count(sym)) {
446 markDependentsLive(sym);
452 switch (sym->getKind()) {
453 case SymExpr::RegionValueKind:
454 KnownLive = isLiveRegion(cast<SymbolRegionValue>(sym)->getRegion());
456 case SymExpr::ConjuredKind:
459 case SymExpr::DerivedKind:
460 KnownLive = isLive(cast<SymbolDerived>(sym)->getParentSymbol());
462 case SymExpr::ExtentKind:
463 KnownLive = isLiveRegion(cast<SymbolExtent>(sym)->getRegion());
465 case SymExpr::MetadataKind:
466 KnownLive = MetadataInUse.count(sym) &&
467 isLiveRegion(cast<SymbolMetadata>(sym)->getRegion());
469 MetadataInUse.erase(sym);
471 case SymExpr::SymIntKind:
472 KnownLive = isLive(cast<SymIntExpr>(sym)->getLHS());
474 case SymExpr::IntSymKind:
475 KnownLive = isLive(cast<IntSymExpr>(sym)->getRHS());
477 case SymExpr::SymSymKind:
478 KnownLive = isLive(cast<SymSymExpr>(sym)->getLHS()) &&
479 isLive(cast<SymSymExpr>(sym)->getRHS());
481 case SymExpr::CastSymbolKind:
482 KnownLive = isLive(cast<SymbolCast>(sym)->getOperand());
493 SymbolReaper::isLive(const Stmt *ExprVal, const LocationContext *ELCtx) const {
498 // If the reaper's location context is a parent of the expression's
499 // location context, then the expression value is now "out of scope".
500 if (LCtx->isParentOf(ELCtx))
505 // If no statement is provided, everything is this and parent contexts is live.
509 return LCtx->getAnalysis<RelaxedLiveVariables>()->isLive(Loc, ExprVal);
512 bool SymbolReaper::isLive(const VarRegion *VR, bool includeStoreBindings) const{
513 const StackFrameContext *VarContext = VR->getStackFrame();
520 const StackFrameContext *CurrentContext = LCtx->getCurrentStackFrame();
522 if (VarContext == CurrentContext) {
523 // If no statement is provided, everything is live.
527 if (LCtx->getAnalysis<RelaxedLiveVariables>()->isLive(Loc, VR->getDecl()))
530 if (!includeStoreBindings)
533 unsigned &cachedQuery =
534 const_cast<SymbolReaper*>(this)->includedRegionCache[VR];
537 return cachedQuery == 1;
540 // Query the store to see if the region occurs in any live bindings.
541 if (Store store = reapedStore.getStore()) {
543 reapedStore.getStoreManager().includedInBindings(store, VR);
544 cachedQuery = hasRegion ? 1 : 2;
551 return VarContext->isParentOf(CurrentContext);
554 SymbolVisitor::~SymbolVisitor() {}