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authorCarlo Zancanaro <carlo@pc-4w14-0.cs.usyd.edu.au>2012-10-15 17:10:06 +1100
committerCarlo Zancanaro <carlo@pc-4w14-0.cs.usyd.edu.au>2012-10-15 17:10:06 +1100
commitbe1de4be954c80875ad4108e0a33e8e131b2f2c0 (patch)
tree1fbbecf276bf7c7bdcbb4dd446099d6d90eaa516 /clang/lib/StaticAnalyzer/Core/SymbolManager.cpp
parentc4626a62754862d20b41e8a46a3574264ea80e6d (diff)
parentf1bd2e48c5324d3f7cda4090c87f8a5b6f463ce2 (diff)
Merge branch 'master' of ssh://bitbucket.org/czan/honours
Diffstat (limited to 'clang/lib/StaticAnalyzer/Core/SymbolManager.cpp')
-rw-r--r--clang/lib/StaticAnalyzer/Core/SymbolManager.cpp540
1 files changed, 540 insertions, 0 deletions
diff --git a/clang/lib/StaticAnalyzer/Core/SymbolManager.cpp b/clang/lib/StaticAnalyzer/Core/SymbolManager.cpp
new file mode 100644
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+++ b/clang/lib/StaticAnalyzer/Core/SymbolManager.cpp
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+//== SymbolManager.h - Management of Symbolic Values ------------*- 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 SymbolManager, a class that manages symbolic values
+// created for use by ExprEngine and related classes.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/StaticAnalyzer/Core/PathSensitive/SymbolManager.h"
+#include "clang/Analysis/Analyses/LiveVariables.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/Store.h"
+#include "llvm/Support/raw_ostream.h"
+
+using namespace clang;
+using namespace ento;
+
+void SymExpr::anchor() { }
+
+void SymExpr::dump() const {
+ dumpToStream(llvm::errs());
+}
+
+static void print(raw_ostream &os, BinaryOperator::Opcode Op) {
+ switch (Op) {
+ default:
+ llvm_unreachable("operator printing not implemented");
+ case BO_Mul: os << '*' ; break;
+ case BO_Div: os << '/' ; break;
+ case BO_Rem: os << '%' ; break;
+ case BO_Add: os << '+' ; break;
+ case BO_Sub: os << '-' ; break;
+ case BO_Shl: os << "<<" ; break;
+ case BO_Shr: os << ">>" ; break;
+ case BO_LT: os << "<" ; break;
+ case BO_GT: os << '>' ; break;
+ case BO_LE: os << "<=" ; break;
+ case BO_GE: os << ">=" ; break;
+ case BO_EQ: os << "==" ; break;
+ case BO_NE: os << "!=" ; break;
+ case BO_And: os << '&' ; break;
+ case BO_Xor: os << '^' ; break;
+ case BO_Or: os << '|' ; break;
+ }
+}
+
+void SymIntExpr::dumpToStream(raw_ostream &os) const {
+ os << '(';
+ getLHS()->dumpToStream(os);
+ os << ") ";
+ print(os, getOpcode());
+ os << ' ' << getRHS().getZExtValue();
+ if (getRHS().isUnsigned()) os << 'U';
+}
+
+void IntSymExpr::dumpToStream(raw_ostream &os) const {
+ os << ' ' << getLHS().getZExtValue();
+ if (getLHS().isUnsigned()) os << 'U';
+ print(os, getOpcode());
+ os << '(';
+ getRHS()->dumpToStream(os);
+ os << ") ";
+}
+
+void SymSymExpr::dumpToStream(raw_ostream &os) const {
+ os << '(';
+ getLHS()->dumpToStream(os);
+ os << ") ";
+ os << '(';
+ getRHS()->dumpToStream(os);
+ os << ')';
+}
+
+void SymbolCast::dumpToStream(raw_ostream &os) const {
+ os << '(' << ToTy.getAsString() << ") (";
+ Operand->dumpToStream(os);
+ os << ')';
+}
+
+void SymbolConjured::dumpToStream(raw_ostream &os) const {
+ os << "conj_$" << getSymbolID() << '{' << T.getAsString() << '}';
+}
+
+void SymbolDerived::dumpToStream(raw_ostream &os) const {
+ os << "derived_$" << getSymbolID() << '{'
+ << getParentSymbol() << ',' << getRegion() << '}';
+}
+
+void SymbolExtent::dumpToStream(raw_ostream &os) const {
+ os << "extent_$" << getSymbolID() << '{' << getRegion() << '}';
+}
+
+void SymbolMetadata::dumpToStream(raw_ostream &os) const {
+ os << "meta_$" << getSymbolID() << '{'
+ << getRegion() << ',' << T.getAsString() << '}';
+}
+
+void SymbolData::anchor() { }
+
+void SymbolRegionValue::dumpToStream(raw_ostream &os) const {
+ os << "reg_$" << getSymbolID() << "<" << R << ">";
+}
+
+bool SymExpr::symbol_iterator::operator==(const symbol_iterator &X) const {
+ return itr == X.itr;
+}
+
+bool SymExpr::symbol_iterator::operator!=(const symbol_iterator &X) const {
+ return itr != X.itr;
+}
+
+SymExpr::symbol_iterator::symbol_iterator(const SymExpr *SE) {
+ itr.push_back(SE);
+ while (!isa<SymbolData>(itr.back())) expand();
+}
+
+SymExpr::symbol_iterator &SymExpr::symbol_iterator::operator++() {
+ assert(!itr.empty() && "attempting to iterate on an 'end' iterator");
+ assert(isa<SymbolData>(itr.back()));
+ itr.pop_back();
+ if (!itr.empty())
+ while (!isa<SymbolData>(itr.back())) expand();
+ return *this;
+}
+
+SymbolRef SymExpr::symbol_iterator::operator*() {
+ assert(!itr.empty() && "attempting to dereference an 'end' iterator");
+ return cast<SymbolData>(itr.back());
+}
+
+void SymExpr::symbol_iterator::expand() {
+ const SymExpr *SE = itr.back();
+ itr.pop_back();
+
+ switch (SE->getKind()) {
+ case SymExpr::RegionValueKind:
+ case SymExpr::ConjuredKind:
+ case SymExpr::DerivedKind:
+ case SymExpr::ExtentKind:
+ case SymExpr::MetadataKind:
+ return;
+ case SymExpr::CastSymbolKind:
+ itr.push_back(cast<SymbolCast>(SE)->getOperand());
+ return;
+ case SymExpr::SymIntKind:
+ itr.push_back(cast<SymIntExpr>(SE)->getLHS());
+ return;
+ case SymExpr::IntSymKind:
+ itr.push_back(cast<IntSymExpr>(SE)->getRHS());
+ return;
+ case SymExpr::SymSymKind: {
+ const SymSymExpr *x = cast<SymSymExpr>(SE);
+ itr.push_back(x->getLHS());
+ itr.push_back(x->getRHS());
+ return;
+ }
+ }
+ llvm_unreachable("unhandled expansion case");
+}
+
+const SymbolRegionValue*
+SymbolManager::getRegionValueSymbol(const TypedValueRegion* R) {
+ llvm::FoldingSetNodeID profile;
+ SymbolRegionValue::Profile(profile, R);
+ void *InsertPos;
+ SymExpr *SD = DataSet.FindNodeOrInsertPos(profile, InsertPos);
+ if (!SD) {
+ SD = (SymExpr*) BPAlloc.Allocate<SymbolRegionValue>();
+ new (SD) SymbolRegionValue(SymbolCounter, R);
+ DataSet.InsertNode(SD, InsertPos);
+ ++SymbolCounter;
+ }
+
+ return cast<SymbolRegionValue>(SD);
+}
+
+const SymbolConjured*
+SymbolManager::getConjuredSymbol(const Stmt *E, const LocationContext *LCtx,
+ QualType T, unsigned Count,
+ const void *SymbolTag) {
+
+ llvm::FoldingSetNodeID profile;
+ SymbolConjured::Profile(profile, E, T, Count, LCtx, SymbolTag);
+ void *InsertPos;
+ SymExpr *SD = DataSet.FindNodeOrInsertPos(profile, InsertPos);
+ if (!SD) {
+ SD = (SymExpr*) BPAlloc.Allocate<SymbolConjured>();
+ new (SD) SymbolConjured(SymbolCounter, E, LCtx, T, Count, SymbolTag);
+ DataSet.InsertNode(SD, InsertPos);
+ ++SymbolCounter;
+ }
+
+ return cast<SymbolConjured>(SD);
+}
+
+const SymbolDerived*
+SymbolManager::getDerivedSymbol(SymbolRef parentSymbol,
+ const TypedValueRegion *R) {
+
+ llvm::FoldingSetNodeID profile;
+ SymbolDerived::Profile(profile, parentSymbol, R);
+ void *InsertPos;
+ SymExpr *SD = DataSet.FindNodeOrInsertPos(profile, InsertPos);
+ if (!SD) {
+ SD = (SymExpr*) BPAlloc.Allocate<SymbolDerived>();
+ new (SD) SymbolDerived(SymbolCounter, parentSymbol, R);
+ DataSet.InsertNode(SD, InsertPos);
+ ++SymbolCounter;
+ }
+
+ return cast<SymbolDerived>(SD);
+}
+
+const SymbolExtent*
+SymbolManager::getExtentSymbol(const SubRegion *R) {
+ llvm::FoldingSetNodeID profile;
+ SymbolExtent::Profile(profile, R);
+ void *InsertPos;
+ SymExpr *SD = DataSet.FindNodeOrInsertPos(profile, InsertPos);
+ if (!SD) {
+ SD = (SymExpr*) BPAlloc.Allocate<SymbolExtent>();
+ new (SD) SymbolExtent(SymbolCounter, R);
+ DataSet.InsertNode(SD, InsertPos);
+ ++SymbolCounter;
+ }
+
+ return cast<SymbolExtent>(SD);
+}
+
+const SymbolMetadata*
+SymbolManager::getMetadataSymbol(const MemRegion* R, const Stmt *S, QualType T,
+ unsigned Count, const void *SymbolTag) {
+
+ llvm::FoldingSetNodeID profile;
+ SymbolMetadata::Profile(profile, R, S, T, Count, SymbolTag);
+ void *InsertPos;
+ SymExpr *SD = DataSet.FindNodeOrInsertPos(profile, InsertPos);
+ if (!SD) {
+ SD = (SymExpr*) BPAlloc.Allocate<SymbolMetadata>();
+ new (SD) SymbolMetadata(SymbolCounter, R, S, T, Count, SymbolTag);
+ DataSet.InsertNode(SD, InsertPos);
+ ++SymbolCounter;
+ }
+
+ return cast<SymbolMetadata>(SD);
+}
+
+const SymbolCast*
+SymbolManager::getCastSymbol(const SymExpr *Op,
+ QualType From, QualType To) {
+ llvm::FoldingSetNodeID ID;
+ SymbolCast::Profile(ID, Op, From, To);
+ void *InsertPos;
+ SymExpr *data = DataSet.FindNodeOrInsertPos(ID, InsertPos);
+ if (!data) {
+ data = (SymbolCast*) BPAlloc.Allocate<SymbolCast>();
+ new (data) SymbolCast(Op, From, To);
+ DataSet.InsertNode(data, InsertPos);
+ }
+
+ return cast<SymbolCast>(data);
+}
+
+const SymIntExpr *SymbolManager::getSymIntExpr(const SymExpr *lhs,
+ BinaryOperator::Opcode op,
+ const llvm::APSInt& v,
+ QualType t) {
+ llvm::FoldingSetNodeID ID;
+ SymIntExpr::Profile(ID, lhs, op, v, t);
+ void *InsertPos;
+ SymExpr *data = DataSet.FindNodeOrInsertPos(ID, InsertPos);
+
+ if (!data) {
+ data = (SymIntExpr*) BPAlloc.Allocate<SymIntExpr>();
+ new (data) SymIntExpr(lhs, op, v, t);
+ DataSet.InsertNode(data, InsertPos);
+ }
+
+ return cast<SymIntExpr>(data);
+}
+
+const IntSymExpr *SymbolManager::getIntSymExpr(const llvm::APSInt& lhs,
+ BinaryOperator::Opcode op,
+ const SymExpr *rhs,
+ QualType t) {
+ llvm::FoldingSetNodeID ID;
+ IntSymExpr::Profile(ID, lhs, op, rhs, t);
+ void *InsertPos;
+ SymExpr *data = DataSet.FindNodeOrInsertPos(ID, InsertPos);
+
+ if (!data) {
+ data = (IntSymExpr*) BPAlloc.Allocate<IntSymExpr>();
+ new (data) IntSymExpr(lhs, op, rhs, t);
+ DataSet.InsertNode(data, InsertPos);
+ }
+
+ return cast<IntSymExpr>(data);
+}
+
+const SymSymExpr *SymbolManager::getSymSymExpr(const SymExpr *lhs,
+ BinaryOperator::Opcode op,
+ const SymExpr *rhs,
+ QualType t) {
+ llvm::FoldingSetNodeID ID;
+ SymSymExpr::Profile(ID, lhs, op, rhs, t);
+ void *InsertPos;
+ SymExpr *data = DataSet.FindNodeOrInsertPos(ID, InsertPos);
+
+ if (!data) {
+ data = (SymSymExpr*) BPAlloc.Allocate<SymSymExpr>();
+ new (data) SymSymExpr(lhs, op, rhs, t);
+ DataSet.InsertNode(data, InsertPos);
+ }
+
+ return cast<SymSymExpr>(data);
+}
+
+QualType SymbolConjured::getType(ASTContext&) const {
+ return T;
+}
+
+QualType SymbolDerived::getType(ASTContext &Ctx) const {
+ return R->getValueType();
+}
+
+QualType SymbolExtent::getType(ASTContext &Ctx) const {
+ return Ctx.getSizeType();
+}
+
+QualType SymbolMetadata::getType(ASTContext&) const {
+ return T;
+}
+
+QualType SymbolRegionValue::getType(ASTContext &C) const {
+ return R->getValueType();
+}
+
+SymbolManager::~SymbolManager() {
+ for (SymbolDependTy::const_iterator I = SymbolDependencies.begin(),
+ E = SymbolDependencies.end(); I != E; ++I) {
+ delete I->second;
+ }
+
+}
+
+bool SymbolManager::canSymbolicate(QualType T) {
+ T = T.getCanonicalType();
+
+ if (Loc::isLocType(T))
+ return true;
+
+ if (T->isIntegerType())
+ return T->isScalarType();
+
+ if (T->isRecordType() && !T->isUnionType())
+ return true;
+
+ return false;
+}
+
+void SymbolManager::addSymbolDependency(const SymbolRef Primary,
+ const SymbolRef Dependent) {
+ SymbolDependTy::iterator I = SymbolDependencies.find(Primary);
+ SymbolRefSmallVectorTy *dependencies = 0;
+ if (I == SymbolDependencies.end()) {
+ dependencies = new SymbolRefSmallVectorTy();
+ SymbolDependencies[Primary] = dependencies;
+ } else {
+ dependencies = I->second;
+ }
+ dependencies->push_back(Dependent);
+}
+
+const SymbolRefSmallVectorTy *SymbolManager::getDependentSymbols(
+ const SymbolRef Primary) {
+ SymbolDependTy::const_iterator I = SymbolDependencies.find(Primary);
+ if (I == SymbolDependencies.end())
+ return 0;
+ return I->second;
+}
+
+void SymbolReaper::markDependentsLive(SymbolRef sym) {
+ // Do not mark dependents more then once.
+ SymbolMapTy::iterator LI = TheLiving.find(sym);
+ assert(LI != TheLiving.end() && "The primary symbol is not live.");
+ if (LI->second == HaveMarkedDependents)
+ return;
+ LI->second = HaveMarkedDependents;
+
+ if (const SymbolRefSmallVectorTy *Deps = SymMgr.getDependentSymbols(sym)) {
+ for (SymbolRefSmallVectorTy::const_iterator I = Deps->begin(),
+ E = Deps->end(); I != E; ++I) {
+ if (TheLiving.find(*I) != TheLiving.end())
+ continue;
+ markLive(*I);
+ }
+ }
+}
+
+void SymbolReaper::markLive(SymbolRef sym) {
+ TheLiving[sym] = NotProcessed;
+ TheDead.erase(sym);
+ markDependentsLive(sym);
+}
+
+void SymbolReaper::markLive(const MemRegion *region) {
+ RegionRoots.insert(region);
+}
+
+void SymbolReaper::markInUse(SymbolRef sym) {
+ if (isa<SymbolMetadata>(sym))
+ MetadataInUse.insert(sym);
+}
+
+bool SymbolReaper::maybeDead(SymbolRef sym) {
+ if (isLive(sym))
+ return false;
+
+ TheDead.insert(sym);
+ return true;
+}
+
+bool SymbolReaper::isLiveRegion(const MemRegion *MR) {
+ if (RegionRoots.count(MR))
+ return true;
+
+ MR = MR->getBaseRegion();
+
+ if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(MR))
+ return isLive(SR->getSymbol());
+
+ if (const VarRegion *VR = dyn_cast<VarRegion>(MR))
+ return isLive(VR, true);
+
+ // FIXME: This is a gross over-approximation. What we really need is a way to
+ // tell if anything still refers to this region. Unlike SymbolicRegions,
+ // AllocaRegions don't have associated symbols, though, so we don't actually
+ // have a way to track their liveness.
+ if (isa<AllocaRegion>(MR))
+ return true;
+
+ if (isa<CXXThisRegion>(MR))
+ return true;
+
+ if (isa<MemSpaceRegion>(MR))
+ return true;
+
+ return false;
+}
+
+bool SymbolReaper::isLive(SymbolRef sym) {
+ if (TheLiving.count(sym)) {
+ markDependentsLive(sym);
+ return true;
+ }
+
+ if (const SymbolDerived *derived = dyn_cast<SymbolDerived>(sym)) {
+ if (isLive(derived->getParentSymbol())) {
+ markLive(sym);
+ return true;
+ }
+ return false;
+ }
+
+ if (const SymbolExtent *extent = dyn_cast<SymbolExtent>(sym)) {
+ if (isLiveRegion(extent->getRegion())) {
+ markLive(sym);
+ return true;
+ }
+ return false;
+ }
+
+ if (const SymbolMetadata *metadata = dyn_cast<SymbolMetadata>(sym)) {
+ if (MetadataInUse.count(sym)) {
+ if (isLiveRegion(metadata->getRegion())) {
+ markLive(sym);
+ MetadataInUse.erase(sym);
+ return true;
+ }
+ }
+ return false;
+ }
+
+ // Interogate the symbol. It may derive from an input value to
+ // the analyzed function/method.
+ return isa<SymbolRegionValue>(sym);
+}
+
+bool
+SymbolReaper::isLive(const Stmt *ExprVal, const LocationContext *ELCtx) const {
+ if (LCtx != ELCtx) {
+ // If the reaper's location context is a parent of the expression's
+ // location context, then the expression value is now "out of scope".
+ if (LCtx->isParentOf(ELCtx))
+ return false;
+ return true;
+ }
+
+ return LCtx->getAnalysis<RelaxedLiveVariables>()->isLive(Loc, ExprVal);
+}
+
+bool SymbolReaper::isLive(const VarRegion *VR, bool includeStoreBindings) const{
+ const StackFrameContext *VarContext = VR->getStackFrame();
+ const StackFrameContext *CurrentContext = LCtx->getCurrentStackFrame();
+
+ if (VarContext == CurrentContext) {
+ if (LCtx->getAnalysis<RelaxedLiveVariables>()->isLive(Loc, VR->getDecl()))
+ return true;
+
+ if (!includeStoreBindings)
+ return false;
+
+ unsigned &cachedQuery =
+ const_cast<SymbolReaper*>(this)->includedRegionCache[VR];
+
+ if (cachedQuery) {
+ return cachedQuery == 1;
+ }
+
+ // Query the store to see if the region occurs in any live bindings.
+ if (Store store = reapedStore.getStore()) {
+ bool hasRegion =
+ reapedStore.getStoreManager().includedInBindings(store, VR);
+ cachedQuery = hasRegion ? 1 : 2;
+ return hasRegion;
+ }
+
+ return false;
+ }
+
+ return VarContext->isParentOf(CurrentContext);
+}
+
+SymbolVisitor::~SymbolVisitor() {}