1 //===- SymbolManager.h - Management of Symbolic Values --------------------===//
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/AST/ASTContext.h"
17 #include "clang/AST/Expr.h"
18 #include "clang/Analysis/Analyses/LiveVariables.h"
19 #include "clang/Analysis/AnalysisDeclContext.h"
20 #include "clang/Basic/LLVM.h"
21 #include "clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h"
22 #include "clang/StaticAnalyzer/Core/PathSensitive/SVals.h"
23 #include "clang/StaticAnalyzer/Core/PathSensitive/Store.h"
24 #include "clang/StaticAnalyzer/Core/PathSensitive/SymExpr.h"
25 #include "llvm/ADT/FoldingSet.h"
26 #include "llvm/ADT/STLExtras.h"
27 #include "llvm/Support/Casting.h"
28 #include "llvm/Support/Compiler.h"
29 #include "llvm/Support/ErrorHandling.h"
30 #include "llvm/Support/raw_ostream.h"
33 using namespace clang;
36 void SymExpr::anchor() {}
38 LLVM_DUMP_METHOD void SymExpr::dump() const {
39 dumpToStream(llvm::errs());
42 void SymIntExpr::dumpToStream(raw_ostream &os) const {
44 getLHS()->dumpToStream(os);
46 << BinaryOperator::getOpcodeStr(getOpcode()) << ' ';
47 if (getRHS().isUnsigned())
48 os << getRHS().getZExtValue();
50 os << getRHS().getSExtValue();
51 if (getRHS().isUnsigned())
55 void IntSymExpr::dumpToStream(raw_ostream &os) const {
56 if (getLHS().isUnsigned())
57 os << getLHS().getZExtValue();
59 os << getLHS().getSExtValue();
60 if (getLHS().isUnsigned())
63 << BinaryOperator::getOpcodeStr(getOpcode())
65 getRHS()->dumpToStream(os);
69 void SymSymExpr::dumpToStream(raw_ostream &os) const {
71 getLHS()->dumpToStream(os);
73 << BinaryOperator::getOpcodeStr(getOpcode())
75 getRHS()->dumpToStream(os);
79 void SymbolCast::dumpToStream(raw_ostream &os) const {
80 os << '(' << ToTy.getAsString() << ") (";
81 Operand->dumpToStream(os);
85 void SymbolConjured::dumpToStream(raw_ostream &os) const {
86 os << "conj_$" << getSymbolID() << '{' << T.getAsString() << '}';
89 void SymbolDerived::dumpToStream(raw_ostream &os) const {
90 os << "derived_$" << getSymbolID() << '{'
91 << getParentSymbol() << ',' << getRegion() << '}';
94 void SymbolExtent::dumpToStream(raw_ostream &os) const {
95 os << "extent_$" << getSymbolID() << '{' << getRegion() << '}';
98 void SymbolMetadata::dumpToStream(raw_ostream &os) const {
99 os << "meta_$" << getSymbolID() << '{'
100 << getRegion() << ',' << T.getAsString() << '}';
103 void SymbolData::anchor() {}
105 void SymbolRegionValue::dumpToStream(raw_ostream &os) const {
106 os << "reg_$" << getSymbolID()
107 << '<' << getType().getAsString() << ' ' << R << '>';
110 bool SymExpr::symbol_iterator::operator==(const symbol_iterator &X) const {
114 bool SymExpr::symbol_iterator::operator!=(const symbol_iterator &X) const {
118 SymExpr::symbol_iterator::symbol_iterator(const SymExpr *SE) {
122 SymExpr::symbol_iterator &SymExpr::symbol_iterator::operator++() {
123 assert(!itr.empty() && "attempting to iterate on an 'end' iterator");
128 SymbolRef SymExpr::symbol_iterator::operator*() {
129 assert(!itr.empty() && "attempting to dereference an 'end' iterator");
133 void SymExpr::symbol_iterator::expand() {
134 const SymExpr *SE = itr.pop_back_val();
136 switch (SE->getKind()) {
137 case SymExpr::SymbolRegionValueKind:
138 case SymExpr::SymbolConjuredKind:
139 case SymExpr::SymbolDerivedKind:
140 case SymExpr::SymbolExtentKind:
141 case SymExpr::SymbolMetadataKind:
143 case SymExpr::SymbolCastKind:
144 itr.push_back(cast<SymbolCast>(SE)->getOperand());
146 case SymExpr::SymIntExprKind:
147 itr.push_back(cast<SymIntExpr>(SE)->getLHS());
149 case SymExpr::IntSymExprKind:
150 itr.push_back(cast<IntSymExpr>(SE)->getRHS());
152 case SymExpr::SymSymExprKind: {
153 const auto *x = cast<SymSymExpr>(SE);
154 itr.push_back(x->getLHS());
155 itr.push_back(x->getRHS());
159 llvm_unreachable("unhandled expansion case");
162 const SymbolRegionValue*
163 SymbolManager::getRegionValueSymbol(const TypedValueRegion* R) {
164 llvm::FoldingSetNodeID profile;
165 SymbolRegionValue::Profile(profile, R);
167 SymExpr *SD = DataSet.FindNodeOrInsertPos(profile, InsertPos);
169 SD = (SymExpr*) BPAlloc.Allocate<SymbolRegionValue>();
170 new (SD) SymbolRegionValue(SymbolCounter, R);
171 DataSet.InsertNode(SD, InsertPos);
175 return cast<SymbolRegionValue>(SD);
178 const SymbolConjured* SymbolManager::conjureSymbol(const Stmt *E,
179 const LocationContext *LCtx,
182 const void *SymbolTag) {
183 llvm::FoldingSetNodeID profile;
184 SymbolConjured::Profile(profile, E, T, Count, LCtx, SymbolTag);
186 SymExpr *SD = DataSet.FindNodeOrInsertPos(profile, InsertPos);
188 SD = (SymExpr*) BPAlloc.Allocate<SymbolConjured>();
189 new (SD) SymbolConjured(SymbolCounter, E, LCtx, T, Count, SymbolTag);
190 DataSet.InsertNode(SD, InsertPos);
194 return cast<SymbolConjured>(SD);
198 SymbolManager::getDerivedSymbol(SymbolRef parentSymbol,
199 const TypedValueRegion *R) {
200 llvm::FoldingSetNodeID profile;
201 SymbolDerived::Profile(profile, parentSymbol, R);
203 SymExpr *SD = DataSet.FindNodeOrInsertPos(profile, InsertPos);
205 SD = (SymExpr*) BPAlloc.Allocate<SymbolDerived>();
206 new (SD) SymbolDerived(SymbolCounter, parentSymbol, R);
207 DataSet.InsertNode(SD, InsertPos);
211 return cast<SymbolDerived>(SD);
215 SymbolManager::getExtentSymbol(const SubRegion *R) {
216 llvm::FoldingSetNodeID profile;
217 SymbolExtent::Profile(profile, R);
219 SymExpr *SD = DataSet.FindNodeOrInsertPos(profile, InsertPos);
221 SD = (SymExpr*) BPAlloc.Allocate<SymbolExtent>();
222 new (SD) SymbolExtent(SymbolCounter, R);
223 DataSet.InsertNode(SD, InsertPos);
227 return cast<SymbolExtent>(SD);
230 const SymbolMetadata *
231 SymbolManager::getMetadataSymbol(const MemRegion* R, const Stmt *S, QualType T,
232 const LocationContext *LCtx,
233 unsigned Count, const void *SymbolTag) {
234 llvm::FoldingSetNodeID profile;
235 SymbolMetadata::Profile(profile, R, S, T, LCtx, Count, SymbolTag);
237 SymExpr *SD = DataSet.FindNodeOrInsertPos(profile, InsertPos);
239 SD = (SymExpr*) BPAlloc.Allocate<SymbolMetadata>();
240 new (SD) SymbolMetadata(SymbolCounter, R, S, T, LCtx, Count, SymbolTag);
241 DataSet.InsertNode(SD, InsertPos);
245 return cast<SymbolMetadata>(SD);
249 SymbolManager::getCastSymbol(const SymExpr *Op,
250 QualType From, QualType To) {
251 llvm::FoldingSetNodeID ID;
252 SymbolCast::Profile(ID, Op, From, To);
254 SymExpr *data = DataSet.FindNodeOrInsertPos(ID, InsertPos);
256 data = (SymbolCast*) BPAlloc.Allocate<SymbolCast>();
257 new (data) SymbolCast(Op, From, To);
258 DataSet.InsertNode(data, InsertPos);
261 return cast<SymbolCast>(data);
264 const SymIntExpr *SymbolManager::getSymIntExpr(const SymExpr *lhs,
265 BinaryOperator::Opcode op,
266 const llvm::APSInt& v,
268 llvm::FoldingSetNodeID ID;
269 SymIntExpr::Profile(ID, lhs, op, v, t);
271 SymExpr *data = DataSet.FindNodeOrInsertPos(ID, InsertPos);
274 data = (SymIntExpr*) BPAlloc.Allocate<SymIntExpr>();
275 new (data) SymIntExpr(lhs, op, v, t);
276 DataSet.InsertNode(data, InsertPos);
279 return cast<SymIntExpr>(data);
282 const IntSymExpr *SymbolManager::getIntSymExpr(const llvm::APSInt& lhs,
283 BinaryOperator::Opcode op,
286 llvm::FoldingSetNodeID ID;
287 IntSymExpr::Profile(ID, lhs, op, rhs, t);
289 SymExpr *data = DataSet.FindNodeOrInsertPos(ID, InsertPos);
292 data = (IntSymExpr*) BPAlloc.Allocate<IntSymExpr>();
293 new (data) IntSymExpr(lhs, op, rhs, t);
294 DataSet.InsertNode(data, InsertPos);
297 return cast<IntSymExpr>(data);
300 const SymSymExpr *SymbolManager::getSymSymExpr(const SymExpr *lhs,
301 BinaryOperator::Opcode op,
304 llvm::FoldingSetNodeID ID;
305 SymSymExpr::Profile(ID, lhs, op, rhs, t);
307 SymExpr *data = DataSet.FindNodeOrInsertPos(ID, InsertPos);
310 data = (SymSymExpr*) BPAlloc.Allocate<SymSymExpr>();
311 new (data) SymSymExpr(lhs, op, rhs, t);
312 DataSet.InsertNode(data, InsertPos);
315 return cast<SymSymExpr>(data);
318 QualType SymbolConjured::getType() const {
322 QualType SymbolDerived::getType() const {
323 return R->getValueType();
326 QualType SymbolExtent::getType() const {
327 ASTContext &Ctx = R->getMemRegionManager()->getContext();
328 return Ctx.getSizeType();
331 QualType SymbolMetadata::getType() const {
335 QualType SymbolRegionValue::getType() const {
336 return R->getValueType();
339 SymbolManager::~SymbolManager() {
340 llvm::DeleteContainerSeconds(SymbolDependencies);
343 bool SymbolManager::canSymbolicate(QualType T) {
344 T = T.getCanonicalType();
346 if (Loc::isLocType(T))
349 if (T->isIntegralOrEnumerationType())
352 if (T->isRecordType() && !T->isUnionType())
358 void SymbolManager::addSymbolDependency(const SymbolRef Primary,
359 const SymbolRef Dependent) {
360 SymbolDependTy::iterator I = SymbolDependencies.find(Primary);
361 SymbolRefSmallVectorTy *dependencies = nullptr;
362 if (I == SymbolDependencies.end()) {
363 dependencies = new SymbolRefSmallVectorTy();
364 SymbolDependencies[Primary] = dependencies;
366 dependencies = I->second;
368 dependencies->push_back(Dependent);
371 const SymbolRefSmallVectorTy *SymbolManager::getDependentSymbols(
372 const SymbolRef Primary) {
373 SymbolDependTy::const_iterator I = SymbolDependencies.find(Primary);
374 if (I == SymbolDependencies.end())
379 void SymbolReaper::markDependentsLive(SymbolRef sym) {
380 // Do not mark dependents more then once.
381 SymbolMapTy::iterator LI = TheLiving.find(sym);
382 assert(LI != TheLiving.end() && "The primary symbol is not live.");
383 if (LI->second == HaveMarkedDependents)
385 LI->second = HaveMarkedDependents;
387 if (const SymbolRefSmallVectorTy *Deps = SymMgr.getDependentSymbols(sym)) {
388 for (const auto I : *Deps) {
389 if (TheLiving.find(I) != TheLiving.end())
396 void SymbolReaper::markLive(SymbolRef sym) {
397 TheLiving[sym] = NotProcessed;
399 markDependentsLive(sym);
402 void SymbolReaper::markLive(const MemRegion *region) {
403 RegionRoots.insert(region);
404 markElementIndicesLive(region);
407 void SymbolReaper::markElementIndicesLive(const MemRegion *region) {
408 for (auto SR = dyn_cast<SubRegion>(region); SR;
409 SR = dyn_cast<SubRegion>(SR->getSuperRegion())) {
410 if (const auto ER = dyn_cast<ElementRegion>(SR)) {
411 SVal Idx = ER->getIndex();
412 for (auto SI = Idx.symbol_begin(), SE = Idx.symbol_end(); SI != SE; ++SI)
418 void SymbolReaper::markInUse(SymbolRef sym) {
419 if (isa<SymbolMetadata>(sym))
420 MetadataInUse.insert(sym);
423 bool SymbolReaper::maybeDead(SymbolRef sym) {
431 bool SymbolReaper::isLiveRegion(const MemRegion *MR) {
432 if (RegionRoots.count(MR))
435 MR = MR->getBaseRegion();
437 if (const auto *SR = dyn_cast<SymbolicRegion>(MR))
438 return isLive(SR->getSymbol());
440 if (const auto *VR = dyn_cast<VarRegion>(MR))
441 return isLive(VR, true);
443 // FIXME: This is a gross over-approximation. What we really need is a way to
444 // tell if anything still refers to this region. Unlike SymbolicRegions,
445 // AllocaRegions don't have associated symbols, though, so we don't actually
446 // have a way to track their liveness.
447 if (isa<AllocaRegion>(MR))
450 if (isa<CXXThisRegion>(MR))
453 if (isa<MemSpaceRegion>(MR))
456 if (isa<CodeTextRegion>(MR))
462 bool SymbolReaper::isLive(SymbolRef sym) {
463 if (TheLiving.count(sym)) {
464 markDependentsLive(sym);
470 switch (sym->getKind()) {
471 case SymExpr::SymbolRegionValueKind:
472 KnownLive = isLiveRegion(cast<SymbolRegionValue>(sym)->getRegion());
474 case SymExpr::SymbolConjuredKind:
477 case SymExpr::SymbolDerivedKind:
478 KnownLive = isLive(cast<SymbolDerived>(sym)->getParentSymbol());
480 case SymExpr::SymbolExtentKind:
481 KnownLive = isLiveRegion(cast<SymbolExtent>(sym)->getRegion());
483 case SymExpr::SymbolMetadataKind:
484 KnownLive = MetadataInUse.count(sym) &&
485 isLiveRegion(cast<SymbolMetadata>(sym)->getRegion());
487 MetadataInUse.erase(sym);
489 case SymExpr::SymIntExprKind:
490 KnownLive = isLive(cast<SymIntExpr>(sym)->getLHS());
492 case SymExpr::IntSymExprKind:
493 KnownLive = isLive(cast<IntSymExpr>(sym)->getRHS());
495 case SymExpr::SymSymExprKind:
496 KnownLive = isLive(cast<SymSymExpr>(sym)->getLHS()) &&
497 isLive(cast<SymSymExpr>(sym)->getRHS());
499 case SymExpr::SymbolCastKind:
500 KnownLive = isLive(cast<SymbolCast>(sym)->getOperand());
511 SymbolReaper::isLive(const Stmt *ExprVal, const LocationContext *ELCtx) const {
516 // If the reaper's location context is a parent of the expression's
517 // location context, then the expression value is now "out of scope".
518 if (LCtx->isParentOf(ELCtx))
523 // If no statement is provided, everything is this and parent contexts is live.
527 return LCtx->getAnalysis<RelaxedLiveVariables>()->isLive(Loc, ExprVal);
530 bool SymbolReaper::isLive(const VarRegion *VR, bool includeStoreBindings) const{
531 const StackFrameContext *VarContext = VR->getStackFrame();
538 const StackFrameContext *CurrentContext = LCtx->getStackFrame();
540 if (VarContext == CurrentContext) {
541 // If no statement is provided, everything is live.
545 if (LCtx->getAnalysis<RelaxedLiveVariables>()->isLive(Loc, VR->getDecl()))
548 if (!includeStoreBindings)
551 unsigned &cachedQuery =
552 const_cast<SymbolReaper *>(this)->includedRegionCache[VR];
555 return cachedQuery == 1;
558 // Query the store to see if the region occurs in any live bindings.
559 if (Store store = reapedStore.getStore()) {
561 reapedStore.getStoreManager().includedInBindings(store, VR);
562 cachedQuery = hasRegion ? 1 : 2;
569 return VarContext->isParentOf(CurrentContext);