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 static void print(raw_ostream &os, BinaryOperator::Opcode Op) {
33 llvm_unreachable("operator printing not implemented");
34 case BO_Mul: os << '*' ; break;
35 case BO_Div: os << '/' ; break;
36 case BO_Rem: os << '%' ; break;
37 case BO_Add: os << '+' ; break;
38 case BO_Sub: os << '-' ; break;
39 case BO_Shl: os << "<<" ; break;
40 case BO_Shr: os << ">>" ; break;
41 case BO_LT: os << "<" ; break;
42 case BO_GT: os << '>' ; break;
43 case BO_LE: os << "<=" ; break;
44 case BO_GE: os << ">=" ; break;
45 case BO_EQ: os << "==" ; break;
46 case BO_NE: os << "!=" ; break;
47 case BO_And: os << '&' ; break;
48 case BO_Xor: os << '^' ; break;
49 case BO_Or: os << '|' ; break;
53 void SymIntExpr::dumpToStream(raw_ostream &os) const {
55 getLHS()->dumpToStream(os);
57 print(os, getOpcode());
58 os << ' ' << getRHS().getZExtValue();
59 if (getRHS().isUnsigned()) os << 'U';
62 void IntSymExpr::dumpToStream(raw_ostream &os) const {
63 os << ' ' << getLHS().getZExtValue();
64 if (getLHS().isUnsigned()) os << 'U';
65 print(os, getOpcode());
67 getRHS()->dumpToStream(os);
71 void SymSymExpr::dumpToStream(raw_ostream &os) const {
73 getLHS()->dumpToStream(os);
76 getRHS()->dumpToStream(os);
80 void SymbolCast::dumpToStream(raw_ostream &os) const {
81 os << '(' << ToTy.getAsString() << ") (";
82 Operand->dumpToStream(os);
86 void SymbolConjured::dumpToStream(raw_ostream &os) const {
87 os << "conj_$" << getSymbolID() << '{' << T.getAsString() << '}';
90 void SymbolDerived::dumpToStream(raw_ostream &os) const {
91 os << "derived_$" << getSymbolID() << '{'
92 << getParentSymbol() << ',' << getRegion() << '}';
95 void SymbolExtent::dumpToStream(raw_ostream &os) const {
96 os << "extent_$" << getSymbolID() << '{' << getRegion() << '}';
99 void SymbolMetadata::dumpToStream(raw_ostream &os) const {
100 os << "meta_$" << getSymbolID() << '{'
101 << getRegion() << ',' << T.getAsString() << '}';
104 void SymbolData::anchor() { }
106 void SymbolRegionValue::dumpToStream(raw_ostream &os) const {
107 os << "reg_$" << getSymbolID() << "<" << 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.back();
137 switch (SE->getKind()) {
138 case SymExpr::RegionValueKind:
139 case SymExpr::ConjuredKind:
140 case SymExpr::DerivedKind:
141 case SymExpr::ExtentKind:
142 case SymExpr::MetadataKind:
144 case SymExpr::CastSymbolKind:
145 itr.push_back(cast<SymbolCast>(SE)->getOperand());
147 case SymExpr::SymIntKind:
148 itr.push_back(cast<SymIntExpr>(SE)->getLHS());
150 case SymExpr::IntSymKind:
151 itr.push_back(cast<IntSymExpr>(SE)->getRHS());
153 case SymExpr::SymSymKind: {
154 const SymSymExpr *x = cast<SymSymExpr>(SE);
155 itr.push_back(x->getLHS());
156 itr.push_back(x->getRHS());
160 llvm_unreachable("unhandled expansion case");
163 unsigned SymExpr::computeComplexity() const {
165 for (symbol_iterator I = symbol_begin(), E = symbol_end(); I != E; ++I)
170 const SymbolRegionValue*
171 SymbolManager::getRegionValueSymbol(const TypedValueRegion* R) {
172 llvm::FoldingSetNodeID profile;
173 SymbolRegionValue::Profile(profile, R);
175 SymExpr *SD = DataSet.FindNodeOrInsertPos(profile, InsertPos);
177 SD = (SymExpr*) BPAlloc.Allocate<SymbolRegionValue>();
178 new (SD) SymbolRegionValue(SymbolCounter, R);
179 DataSet.InsertNode(SD, InsertPos);
183 return cast<SymbolRegionValue>(SD);
186 const SymbolConjured* SymbolManager::conjureSymbol(const Stmt *E,
187 const LocationContext *LCtx,
190 const void *SymbolTag) {
191 llvm::FoldingSetNodeID profile;
192 SymbolConjured::Profile(profile, E, T, Count, LCtx, SymbolTag);
194 SymExpr *SD = DataSet.FindNodeOrInsertPos(profile, InsertPos);
196 SD = (SymExpr*) BPAlloc.Allocate<SymbolConjured>();
197 new (SD) SymbolConjured(SymbolCounter, E, LCtx, T, Count, SymbolTag);
198 DataSet.InsertNode(SD, InsertPos);
202 return cast<SymbolConjured>(SD);
206 SymbolManager::getDerivedSymbol(SymbolRef parentSymbol,
207 const TypedValueRegion *R) {
209 llvm::FoldingSetNodeID profile;
210 SymbolDerived::Profile(profile, parentSymbol, R);
212 SymExpr *SD = DataSet.FindNodeOrInsertPos(profile, InsertPos);
214 SD = (SymExpr*) BPAlloc.Allocate<SymbolDerived>();
215 new (SD) SymbolDerived(SymbolCounter, parentSymbol, R);
216 DataSet.InsertNode(SD, InsertPos);
220 return cast<SymbolDerived>(SD);
224 SymbolManager::getExtentSymbol(const SubRegion *R) {
225 llvm::FoldingSetNodeID profile;
226 SymbolExtent::Profile(profile, R);
228 SymExpr *SD = DataSet.FindNodeOrInsertPos(profile, InsertPos);
230 SD = (SymExpr*) BPAlloc.Allocate<SymbolExtent>();
231 new (SD) SymbolExtent(SymbolCounter, R);
232 DataSet.InsertNode(SD, InsertPos);
236 return cast<SymbolExtent>(SD);
239 const SymbolMetadata*
240 SymbolManager::getMetadataSymbol(const MemRegion* R, const Stmt *S, QualType T,
241 unsigned Count, const void *SymbolTag) {
243 llvm::FoldingSetNodeID profile;
244 SymbolMetadata::Profile(profile, R, S, T, Count, SymbolTag);
246 SymExpr *SD = DataSet.FindNodeOrInsertPos(profile, InsertPos);
248 SD = (SymExpr*) BPAlloc.Allocate<SymbolMetadata>();
249 new (SD) SymbolMetadata(SymbolCounter, R, S, T, Count, SymbolTag);
250 DataSet.InsertNode(SD, InsertPos);
254 return cast<SymbolMetadata>(SD);
258 SymbolManager::getCastSymbol(const SymExpr *Op,
259 QualType From, QualType To) {
260 llvm::FoldingSetNodeID ID;
261 SymbolCast::Profile(ID, Op, From, To);
263 SymExpr *data = DataSet.FindNodeOrInsertPos(ID, InsertPos);
265 data = (SymbolCast*) BPAlloc.Allocate<SymbolCast>();
266 new (data) SymbolCast(Op, From, To);
267 DataSet.InsertNode(data, InsertPos);
270 return cast<SymbolCast>(data);
273 const SymIntExpr *SymbolManager::getSymIntExpr(const SymExpr *lhs,
274 BinaryOperator::Opcode op,
275 const llvm::APSInt& v,
277 llvm::FoldingSetNodeID ID;
278 SymIntExpr::Profile(ID, lhs, op, v, t);
280 SymExpr *data = DataSet.FindNodeOrInsertPos(ID, InsertPos);
283 data = (SymIntExpr*) BPAlloc.Allocate<SymIntExpr>();
284 new (data) SymIntExpr(lhs, op, v, t);
285 DataSet.InsertNode(data, InsertPos);
288 return cast<SymIntExpr>(data);
291 const IntSymExpr *SymbolManager::getIntSymExpr(const llvm::APSInt& lhs,
292 BinaryOperator::Opcode op,
295 llvm::FoldingSetNodeID ID;
296 IntSymExpr::Profile(ID, lhs, op, rhs, t);
298 SymExpr *data = DataSet.FindNodeOrInsertPos(ID, InsertPos);
301 data = (IntSymExpr*) BPAlloc.Allocate<IntSymExpr>();
302 new (data) IntSymExpr(lhs, op, rhs, t);
303 DataSet.InsertNode(data, InsertPos);
306 return cast<IntSymExpr>(data);
309 const SymSymExpr *SymbolManager::getSymSymExpr(const SymExpr *lhs,
310 BinaryOperator::Opcode op,
313 llvm::FoldingSetNodeID ID;
314 SymSymExpr::Profile(ID, lhs, op, rhs, t);
316 SymExpr *data = DataSet.FindNodeOrInsertPos(ID, InsertPos);
319 data = (SymSymExpr*) BPAlloc.Allocate<SymSymExpr>();
320 new (data) SymSymExpr(lhs, op, rhs, t);
321 DataSet.InsertNode(data, InsertPos);
324 return cast<SymSymExpr>(data);
327 QualType SymbolConjured::getType() const {
331 QualType SymbolDerived::getType() const {
332 return R->getValueType();
335 QualType SymbolExtent::getType() const {
336 ASTContext &Ctx = R->getMemRegionManager()->getContext();
337 return Ctx.getSizeType();
340 QualType SymbolMetadata::getType() const {
344 QualType SymbolRegionValue::getType() const {
345 return R->getValueType();
348 SymbolManager::~SymbolManager() {
349 for (SymbolDependTy::const_iterator I = SymbolDependencies.begin(),
350 E = SymbolDependencies.end(); I != E; ++I) {
356 bool SymbolManager::canSymbolicate(QualType T) {
357 T = T.getCanonicalType();
359 if (Loc::isLocType(T))
362 if (T->isIntegerType())
363 return T->isScalarType();
365 if (T->isRecordType() && !T->isUnionType())
371 void SymbolManager::addSymbolDependency(const SymbolRef Primary,
372 const SymbolRef Dependent) {
373 SymbolDependTy::iterator I = SymbolDependencies.find(Primary);
374 SymbolRefSmallVectorTy *dependencies = 0;
375 if (I == SymbolDependencies.end()) {
376 dependencies = new SymbolRefSmallVectorTy();
377 SymbolDependencies[Primary] = dependencies;
379 dependencies = I->second;
381 dependencies->push_back(Dependent);
384 const SymbolRefSmallVectorTy *SymbolManager::getDependentSymbols(
385 const SymbolRef Primary) {
386 SymbolDependTy::const_iterator I = SymbolDependencies.find(Primary);
387 if (I == SymbolDependencies.end())
392 void SymbolReaper::markDependentsLive(SymbolRef sym) {
393 // Do not mark dependents more then once.
394 SymbolMapTy::iterator LI = TheLiving.find(sym);
395 assert(LI != TheLiving.end() && "The primary symbol is not live.");
396 if (LI->second == HaveMarkedDependents)
398 LI->second = HaveMarkedDependents;
400 if (const SymbolRefSmallVectorTy *Deps = SymMgr.getDependentSymbols(sym)) {
401 for (SymbolRefSmallVectorTy::const_iterator I = Deps->begin(),
402 E = Deps->end(); I != E; ++I) {
403 if (TheLiving.find(*I) != TheLiving.end())
410 void SymbolReaper::markLive(SymbolRef sym) {
411 TheLiving[sym] = NotProcessed;
413 markDependentsLive(sym);
416 void SymbolReaper::markLive(const MemRegion *region) {
417 RegionRoots.insert(region);
420 void SymbolReaper::markInUse(SymbolRef sym) {
421 if (isa<SymbolMetadata>(sym))
422 MetadataInUse.insert(sym);
425 bool SymbolReaper::maybeDead(SymbolRef sym) {
433 bool SymbolReaper::isLiveRegion(const MemRegion *MR) {
434 if (RegionRoots.count(MR))
437 MR = MR->getBaseRegion();
439 if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(MR))
440 return isLive(SR->getSymbol());
442 if (const VarRegion *VR = dyn_cast<VarRegion>(MR))
443 return isLive(VR, true);
445 // FIXME: This is a gross over-approximation. What we really need is a way to
446 // tell if anything still refers to this region. Unlike SymbolicRegions,
447 // AllocaRegions don't have associated symbols, though, so we don't actually
448 // have a way to track their liveness.
449 if (isa<AllocaRegion>(MR))
452 if (isa<CXXThisRegion>(MR))
455 if (isa<MemSpaceRegion>(MR))
461 bool SymbolReaper::isLive(SymbolRef sym) {
462 if (TheLiving.count(sym)) {
463 markDependentsLive(sym);
469 switch (sym->getKind()) {
470 case SymExpr::RegionValueKind:
471 // FIXME: We should be able to use isLiveRegion here (this behavior
472 // predates isLiveRegion), but doing so causes test failures. Investigate.
475 case SymExpr::ConjuredKind:
478 case SymExpr::DerivedKind:
479 KnownLive = isLive(cast<SymbolDerived>(sym)->getParentSymbol());
481 case SymExpr::ExtentKind:
482 KnownLive = isLiveRegion(cast<SymbolExtent>(sym)->getRegion());
484 case SymExpr::MetadataKind:
485 KnownLive = MetadataInUse.count(sym) &&
486 isLiveRegion(cast<SymbolMetadata>(sym)->getRegion());
488 MetadataInUse.erase(sym);
490 case SymExpr::SymIntKind:
491 KnownLive = isLive(cast<SymIntExpr>(sym)->getLHS());
493 case SymExpr::IntSymKind:
494 KnownLive = isLive(cast<IntSymExpr>(sym)->getRHS());
496 case SymExpr::SymSymKind:
497 KnownLive = isLive(cast<SymSymExpr>(sym)->getLHS()) &&
498 isLive(cast<SymSymExpr>(sym)->getRHS());
500 case SymExpr::CastSymbolKind:
501 KnownLive = isLive(cast<SymbolCast>(sym)->getOperand());
512 SymbolReaper::isLive(const Stmt *ExprVal, const LocationContext *ELCtx) const {
517 // If the reaper's location context is a parent of the expression's
518 // location context, then the expression value is now "out of scope".
519 if (LCtx->isParentOf(ELCtx))
524 // If no statement is provided, everything is this and parent contexts is live.
528 return LCtx->getAnalysis<RelaxedLiveVariables>()->isLive(Loc, ExprVal);
531 bool SymbolReaper::isLive(const VarRegion *VR, bool includeStoreBindings) const{
532 const StackFrameContext *VarContext = VR->getStackFrame();
539 const StackFrameContext *CurrentContext = LCtx->getCurrentStackFrame();
541 if (VarContext == CurrentContext) {
542 // If no statement is provided, everything is live.
546 if (LCtx->getAnalysis<RelaxedLiveVariables>()->isLive(Loc, VR->getDecl()))
549 if (!includeStoreBindings)
552 unsigned &cachedQuery =
553 const_cast<SymbolReaper*>(this)->includedRegionCache[VR];
556 return cachedQuery == 1;
559 // Query the store to see if the region occurs in any live bindings.
560 if (Store store = reapedStore.getStore()) {
562 reapedStore.getStoreManager().includedInBindings(store, VR);
563 cachedQuery = hasRegion ? 1 : 2;
570 return VarContext->isParentOf(CurrentContext);
573 SymbolVisitor::~SymbolVisitor() {}