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dd331082e7
Replace the family of `SymbolManager::get*Symbol(...)` member functions with a single generic `SymbolManager::get<*>` member function.
415 lines
12 KiB
C++
415 lines
12 KiB
C++
//===- SymbolManager.h - Management of Symbolic Values --------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This file defines SymbolManager, a class that manages symbolic values
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// created for use by ExprEngine and related classes.
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//
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//===----------------------------------------------------------------------===//
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#include "clang/StaticAnalyzer/Core/PathSensitive/SymbolManager.h"
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#include "clang/AST/ASTContext.h"
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#include "clang/AST/Expr.h"
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#include "clang/AST/StmtObjC.h"
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#include "clang/Analysis/Analyses/LiveVariables.h"
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#include "clang/Analysis/AnalysisDeclContext.h"
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#include "clang/Basic/LLVM.h"
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#include "clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h"
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#include "clang/StaticAnalyzer/Core/PathSensitive/SVals.h"
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#include "clang/StaticAnalyzer/Core/PathSensitive/Store.h"
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#include "clang/StaticAnalyzer/Core/PathSensitive/SymExpr.h"
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#include "llvm/ADT/FoldingSet.h"
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#include "llvm/ADT/STLExtras.h"
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#include "llvm/Support/Casting.h"
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#include "llvm/Support/Compiler.h"
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#include "llvm/Support/ErrorHandling.h"
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#include "llvm/Support/raw_ostream.h"
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#include <cassert>
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using namespace clang;
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using namespace ento;
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void SymExpr::anchor() {}
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StringRef SymbolConjured::getKindStr() const { return "conj_$"; }
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StringRef SymbolDerived::getKindStr() const { return "derived_$"; }
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StringRef SymbolExtent::getKindStr() const { return "extent_$"; }
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StringRef SymbolMetadata::getKindStr() const { return "meta_$"; }
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StringRef SymbolRegionValue::getKindStr() const { return "reg_$"; }
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LLVM_DUMP_METHOD void SymExpr::dump() const { dumpToStream(llvm::errs()); }
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void BinarySymExpr::dumpToStreamImpl(raw_ostream &OS, const SymExpr *Sym) {
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OS << '(';
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Sym->dumpToStream(OS);
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OS << ')';
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}
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void BinarySymExpr::dumpToStreamImpl(raw_ostream &OS,
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const llvm::APSInt &Value) {
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if (Value.isUnsigned())
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OS << Value.getZExtValue();
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else
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OS << Value.getSExtValue();
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if (Value.isUnsigned())
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OS << 'U';
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}
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void BinarySymExpr::dumpToStreamImpl(raw_ostream &OS,
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BinaryOperator::Opcode Op) {
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OS << ' ' << BinaryOperator::getOpcodeStr(Op) << ' ';
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}
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void SymbolCast::dumpToStream(raw_ostream &os) const {
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os << '(' << ToTy << ") (";
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Operand->dumpToStream(os);
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os << ')';
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}
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void UnarySymExpr::dumpToStream(raw_ostream &os) const {
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os << UnaryOperator::getOpcodeStr(Op);
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bool Binary = isa<BinarySymExpr>(Operand);
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if (Binary)
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os << '(';
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Operand->dumpToStream(os);
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if (Binary)
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os << ')';
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}
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void SymbolConjured::dumpToStream(raw_ostream &os) const {
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os << getKindStr() << getSymbolID() << '{' << T << ", LC" << LCtx->getID();
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if (S)
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os << ", S" << S->getID(LCtx->getDecl()->getASTContext());
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else
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os << ", no stmt";
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os << ", #" << Count << '}';
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}
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void SymbolDerived::dumpToStream(raw_ostream &os) const {
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os << getKindStr() << getSymbolID() << '{' << getParentSymbol() << ','
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<< getRegion() << '}';
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}
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void SymbolExtent::dumpToStream(raw_ostream &os) const {
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os << getKindStr() << getSymbolID() << '{' << getRegion() << '}';
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}
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void SymbolMetadata::dumpToStream(raw_ostream &os) const {
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os << getKindStr() << getSymbolID() << '{' << getRegion() << ',' << T << '}';
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}
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void SymbolData::anchor() {}
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void SymbolRegionValue::dumpToStream(raw_ostream &os) const {
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os << getKindStr() << getSymbolID() << '<' << getType() << ' ' << R << '>';
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}
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bool SymExpr::symbol_iterator::operator==(const symbol_iterator &X) const {
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return itr == X.itr;
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}
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bool SymExpr::symbol_iterator::operator!=(const symbol_iterator &X) const {
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return itr != X.itr;
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}
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SymExpr::symbol_iterator::symbol_iterator(const SymExpr *SE) {
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itr.push_back(SE);
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}
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SymExpr::symbol_iterator &SymExpr::symbol_iterator::operator++() {
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assert(!itr.empty() && "attempting to iterate on an 'end' iterator");
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expand();
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return *this;
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}
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SymbolRef SymExpr::symbol_iterator::operator*() {
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assert(!itr.empty() && "attempting to dereference an 'end' iterator");
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return itr.back();
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}
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void SymExpr::symbol_iterator::expand() {
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const SymExpr *SE = itr.pop_back_val();
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switch (SE->getKind()) {
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case SymExpr::SymbolRegionValueKind:
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case SymExpr::SymbolConjuredKind:
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case SymExpr::SymbolDerivedKind:
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case SymExpr::SymbolExtentKind:
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case SymExpr::SymbolMetadataKind:
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return;
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case SymExpr::SymbolCastKind:
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itr.push_back(cast<SymbolCast>(SE)->getOperand());
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return;
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case SymExpr::UnarySymExprKind:
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itr.push_back(cast<UnarySymExpr>(SE)->getOperand());
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return;
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case SymExpr::SymIntExprKind:
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itr.push_back(cast<SymIntExpr>(SE)->getLHS());
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return;
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case SymExpr::IntSymExprKind:
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itr.push_back(cast<IntSymExpr>(SE)->getRHS());
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return;
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case SymExpr::SymSymExprKind: {
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const auto *x = cast<SymSymExpr>(SE);
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itr.push_back(x->getLHS());
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itr.push_back(x->getRHS());
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return;
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}
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}
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llvm_unreachable("unhandled expansion case");
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}
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QualType SymbolConjured::getType() const {
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return T;
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}
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QualType SymbolDerived::getType() const {
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return R->getValueType();
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}
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QualType SymbolExtent::getType() const {
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ASTContext &Ctx = R->getMemRegionManager().getContext();
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return Ctx.getSizeType();
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}
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QualType SymbolMetadata::getType() const {
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return T;
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}
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QualType SymbolRegionValue::getType() const {
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return R->getValueType();
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}
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bool SymbolManager::canSymbolicate(QualType T) {
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T = T.getCanonicalType();
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if (Loc::isLocType(T))
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return true;
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if (T->isIntegralOrEnumerationType())
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return true;
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if (T->isRecordType() && !T->isUnionType())
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return true;
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return false;
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}
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void SymbolManager::addSymbolDependency(const SymbolRef Primary,
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const SymbolRef Dependent) {
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auto &dependencies = SymbolDependencies[Primary];
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if (!dependencies) {
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dependencies = std::make_unique<SymbolRefSmallVectorTy>();
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}
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dependencies->push_back(Dependent);
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}
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const SymbolRefSmallVectorTy *SymbolManager::getDependentSymbols(
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const SymbolRef Primary) {
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SymbolDependTy::const_iterator I = SymbolDependencies.find(Primary);
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if (I == SymbolDependencies.end())
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return nullptr;
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return I->second.get();
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}
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void SymbolReaper::markDependentsLive(SymbolRef sym) {
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// Do not mark dependents more then once.
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SymbolMapTy::iterator LI = TheLiving.find(sym);
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assert(LI != TheLiving.end() && "The primary symbol is not live.");
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if (LI->second == HaveMarkedDependents)
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return;
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LI->second = HaveMarkedDependents;
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if (const SymbolRefSmallVectorTy *Deps = SymMgr.getDependentSymbols(sym)) {
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for (const auto I : *Deps) {
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if (TheLiving.contains(I))
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continue;
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markLive(I);
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}
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}
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}
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void SymbolReaper::markLive(SymbolRef sym) {
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TheLiving[sym] = NotProcessed;
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markDependentsLive(sym);
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}
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void SymbolReaper::markLive(const MemRegion *region) {
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LiveRegionRoots.insert(region->getBaseRegion());
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markElementIndicesLive(region);
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}
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void SymbolReaper::markLazilyCopied(const clang::ento::MemRegion *region) {
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LazilyCopiedRegionRoots.insert(region->getBaseRegion());
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}
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void SymbolReaper::markElementIndicesLive(const MemRegion *region) {
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for (auto SR = dyn_cast<SubRegion>(region); SR;
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SR = dyn_cast<SubRegion>(SR->getSuperRegion())) {
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if (const auto ER = dyn_cast<ElementRegion>(SR)) {
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SVal Idx = ER->getIndex();
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for (SymbolRef Sym : Idx.symbols())
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markLive(Sym);
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}
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}
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}
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void SymbolReaper::markInUse(SymbolRef sym) {
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if (isa<SymbolMetadata>(sym))
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MetadataInUse.insert(sym);
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}
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bool SymbolReaper::isLiveRegion(const MemRegion *MR) {
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// TODO: For now, liveness of a memory region is equivalent to liveness of its
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// base region. In fact we can do a bit better: say, if a particular FieldDecl
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// is not used later in the path, we can diagnose a leak of a value within
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// that field earlier than, say, the variable that contains the field dies.
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MR = MR->getBaseRegion();
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if (LiveRegionRoots.count(MR))
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return true;
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if (const auto *SR = dyn_cast<SymbolicRegion>(MR))
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return isLive(SR->getSymbol());
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if (const auto *VR = dyn_cast<VarRegion>(MR))
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return isLive(VR, true);
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// FIXME: This is a gross over-approximation. What we really need is a way to
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// tell if anything still refers to this region. Unlike SymbolicRegions,
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// AllocaRegions don't have associated symbols, though, so we don't actually
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// have a way to track their liveness.
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return isa<AllocaRegion, CXXThisRegion, MemSpaceRegion, CodeTextRegion>(MR);
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}
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bool SymbolReaper::isLazilyCopiedRegion(const MemRegion *MR) const {
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// TODO: See comment in isLiveRegion.
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return LazilyCopiedRegionRoots.count(MR->getBaseRegion());
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}
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bool SymbolReaper::isReadableRegion(const MemRegion *MR) {
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return isLiveRegion(MR) || isLazilyCopiedRegion(MR);
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}
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bool SymbolReaper::isLive(SymbolRef sym) {
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if (TheLiving.count(sym)) {
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markDependentsLive(sym);
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return true;
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}
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bool KnownLive;
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switch (sym->getKind()) {
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case SymExpr::SymbolRegionValueKind:
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KnownLive = isReadableRegion(cast<SymbolRegionValue>(sym)->getRegion());
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break;
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case SymExpr::SymbolConjuredKind:
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KnownLive = false;
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break;
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case SymExpr::SymbolDerivedKind:
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KnownLive = isLive(cast<SymbolDerived>(sym)->getParentSymbol());
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break;
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case SymExpr::SymbolExtentKind:
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KnownLive = isLiveRegion(cast<SymbolExtent>(sym)->getRegion());
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break;
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case SymExpr::SymbolMetadataKind:
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KnownLive = MetadataInUse.count(sym) &&
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isLiveRegion(cast<SymbolMetadata>(sym)->getRegion());
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if (KnownLive)
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MetadataInUse.erase(sym);
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break;
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case SymExpr::SymIntExprKind:
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KnownLive = isLive(cast<SymIntExpr>(sym)->getLHS());
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break;
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case SymExpr::IntSymExprKind:
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KnownLive = isLive(cast<IntSymExpr>(sym)->getRHS());
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break;
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case SymExpr::SymSymExprKind:
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KnownLive = isLive(cast<SymSymExpr>(sym)->getLHS()) &&
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isLive(cast<SymSymExpr>(sym)->getRHS());
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break;
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case SymExpr::SymbolCastKind:
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KnownLive = isLive(cast<SymbolCast>(sym)->getOperand());
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break;
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case SymExpr::UnarySymExprKind:
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KnownLive = isLive(cast<UnarySymExpr>(sym)->getOperand());
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break;
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}
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if (KnownLive)
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markLive(sym);
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return KnownLive;
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}
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bool
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SymbolReaper::isLive(const Expr *ExprVal, const LocationContext *ELCtx) const {
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if (LCtx == nullptr)
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return false;
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if (LCtx != ELCtx) {
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// If the reaper's location context is a parent of the expression's
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// location context, then the expression value is now "out of scope".
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if (LCtx->isParentOf(ELCtx))
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return false;
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return true;
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}
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// If no statement is provided, everything in this and parent contexts is
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// live.
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if (!Loc)
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return true;
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return LCtx->getAnalysis<RelaxedLiveVariables>()->isLive(Loc, ExprVal);
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}
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bool SymbolReaper::isLive(const VarRegion *VR, bool includeStoreBindings) const{
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const StackFrameContext *VarContext = VR->getStackFrame();
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if (!VarContext)
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return true;
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if (!LCtx)
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return false;
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const StackFrameContext *CurrentContext = LCtx->getStackFrame();
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if (VarContext == CurrentContext) {
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// If no statement is provided, everything is live.
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if (!Loc)
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return true;
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// Anonymous parameters of an inheriting constructor are live for the entire
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// duration of the constructor.
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if (isa<CXXInheritedCtorInitExpr>(Loc))
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return true;
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if (LCtx->getAnalysis<RelaxedLiveVariables>()->isLive(Loc, VR->getDecl()))
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return true;
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if (!includeStoreBindings)
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return false;
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unsigned &cachedQuery =
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const_cast<SymbolReaper *>(this)->includedRegionCache[VR];
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if (cachedQuery) {
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return cachedQuery == 1;
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}
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// Query the store to see if the region occurs in any live bindings.
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if (Store store = reapedStore.getStore()) {
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bool hasRegion =
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reapedStore.getStoreManager().includedInBindings(store, VR);
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cachedQuery = hasRegion ? 1 : 2;
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return hasRegion;
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}
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return false;
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}
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return VarContext->isParentOf(CurrentContext);
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}
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