458 lines
14 KiB
C++
458 lines
14 KiB
C++
//= RValues.cpp - Abstract RValues for Path-Sens. Value Tracking -*- C++ -*-==//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file defines SVal, Loc, and NonLoc, classes that represent
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// abstract r-values for use with path-sensitive value tracking.
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//
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//===----------------------------------------------------------------------===//
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#include "clang/Analysis/PathSensitive/GRState.h"
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#include "clang/Basic/IdentifierTable.h"
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#include "llvm/Support/Streams.h"
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using namespace clang;
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using llvm::dyn_cast;
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using llvm::cast;
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using llvm::APSInt;
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//===----------------------------------------------------------------------===//
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// Symbol iteration within an SVal.
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//===----------------------------------------------------------------------===//
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//===----------------------------------------------------------------------===//
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// Utility methods.
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//===----------------------------------------------------------------------===//
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/// getAsLocSymbol - If this SVal is a location (subclasses Loc) and
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/// wraps a symbol, return that SymbolRef. Otherwise return a SymbolRef
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/// where 'isValid()' returns false.
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SymbolRef SVal::getAsLocSymbol() const {
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if (const loc::SymbolVal *X = dyn_cast<loc::SymbolVal>(this))
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return X->getSymbol();
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if (const loc::MemRegionVal *X = dyn_cast<loc::MemRegionVal>(this)) {
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const MemRegion *R = X->getRegion();
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while (R) {
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// Blast through region views.
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if (const TypedViewRegion *View = dyn_cast<TypedViewRegion>(R)) {
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R = View->getSuperRegion();
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continue;
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}
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if (const SymbolicRegion *SymR = dyn_cast<SymbolicRegion>(R))
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return SymR->getSymbol();
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break;
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}
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}
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return 0;
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}
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/// getAsSymbol - If this Sval wraps a symbol return that SymbolRef.
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/// Otherwise return a SymbolRef where 'isValid()' returns false.
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SymbolRef SVal::getAsSymbol() const {
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if (const nonloc::SymbolVal *X = dyn_cast<nonloc::SymbolVal>(this))
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return X->getSymbol();
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if (const nonloc::SymExprVal *X = dyn_cast<nonloc::SymExprVal>(this))
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if (SymbolRef Y = dyn_cast<SymbolData>(X->getSymbolicExpression()))
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return Y;
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return getAsLocSymbol();
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}
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/// getAsSymbolicExpression - If this Sval wraps a symbolic expression then
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/// return that expression. Otherwise return NULL.
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const SymExpr *SVal::getAsSymbolicExpression() const {
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if (const nonloc::SymExprVal *X = dyn_cast<nonloc::SymExprVal>(this))
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return X->getSymbolicExpression();
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return getAsSymbol();
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}
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bool SVal::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 SVal::symbol_iterator::operator!=(const symbol_iterator &X) const {
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return itr != X.itr;
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}
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SVal::symbol_iterator::symbol_iterator(const SymExpr *SE) {
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itr.push_back(SE);
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while (!isa<SymbolData>(itr.back())) expand();
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}
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SVal::symbol_iterator& SVal::symbol_iterator::operator++() {
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assert(!itr.empty() && "attempting to iterate on an 'end' iterator");
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assert(isa<SymbolData>(itr.back()));
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itr.pop_back();
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if (!itr.empty())
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while (!isa<SymbolData>(itr.back())) expand();
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return *this;
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}
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SymbolRef SVal::symbol_iterator::operator*() {
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assert(!itr.empty() && "attempting to dereference an 'end' iterator");
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return cast<SymbolData>(itr.back());
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}
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void SVal::symbol_iterator::expand() {
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const SymExpr *SE = itr.back();
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itr.pop_back();
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if (const SymIntExpr *SIE = dyn_cast<SymIntExpr>(SE)) {
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itr.push_back(SIE->getLHS());
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return;
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}
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else if (const SymSymExpr *SSE = dyn_cast<SymSymExpr>(SE)) {
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itr.push_back(SSE->getLHS());
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itr.push_back(SSE->getRHS());
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return;
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}
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assert(false && "unhandled expansion case");
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}
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//===----------------------------------------------------------------------===//
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// Other Iterators.
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//===----------------------------------------------------------------------===//
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nonloc::CompoundVal::iterator nonloc::CompoundVal::begin() const {
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return getValue()->begin();
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}
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nonloc::CompoundVal::iterator nonloc::CompoundVal::end() const {
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return getValue()->end();
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}
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//===----------------------------------------------------------------------===//
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// Useful predicates.
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//===----------------------------------------------------------------------===//
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bool SVal::isZeroConstant() const {
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if (isa<loc::ConcreteInt>(*this))
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return cast<loc::ConcreteInt>(*this).getValue() == 0;
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else if (isa<nonloc::ConcreteInt>(*this))
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return cast<nonloc::ConcreteInt>(*this).getValue() == 0;
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else
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return false;
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}
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//===----------------------------------------------------------------------===//
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// Transfer function dispatch for Non-Locs.
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//===----------------------------------------------------------------------===//
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SVal nonloc::ConcreteInt::EvalBinOp(BasicValueFactory& BasicVals,
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BinaryOperator::Opcode Op,
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const nonloc::ConcreteInt& R) const {
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const llvm::APSInt* X =
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BasicVals.EvaluateAPSInt(Op, getValue(), R.getValue());
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if (X)
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return nonloc::ConcreteInt(*X);
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else
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return UndefinedVal();
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}
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// Bitwise-Complement.
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nonloc::ConcreteInt
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nonloc::ConcreteInt::EvalComplement(BasicValueFactory& BasicVals) const {
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return BasicVals.getValue(~getValue());
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}
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// Unary Minus.
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nonloc::ConcreteInt
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nonloc::ConcreteInt::EvalMinus(BasicValueFactory& BasicVals, UnaryOperator* U) const {
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assert (U->getType() == U->getSubExpr()->getType());
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assert (U->getType()->isIntegerType());
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return BasicVals.getValue(-getValue());
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}
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//===----------------------------------------------------------------------===//
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// Transfer function dispatch for Locs.
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//===----------------------------------------------------------------------===//
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SVal loc::ConcreteInt::EvalBinOp(BasicValueFactory& BasicVals,
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BinaryOperator::Opcode Op,
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const loc::ConcreteInt& R) const {
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assert (Op == BinaryOperator::Add || Op == BinaryOperator::Sub ||
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(Op >= BinaryOperator::LT && Op <= BinaryOperator::NE));
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const llvm::APSInt* X = BasicVals.EvaluateAPSInt(Op, getValue(), R.getValue());
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if (X)
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return loc::ConcreteInt(*X);
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else
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return UndefinedVal();
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}
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//===----------------------------------------------------------------------===//
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// Utility methods for constructing SVals.
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//===----------------------------------------------------------------------===//
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SVal ValueManager::makeZeroVal(QualType T) {
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if (Loc::IsLocType(T))
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return Loc::MakeNull(BasicVals);
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if (T->isIntegerType())
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return NonLoc::MakeVal(BasicVals, 0, T);
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// FIXME: Handle floats.
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// FIXME: Handle structs.
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return UnknownVal();
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}
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//===----------------------------------------------------------------------===//
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// Utility methods for constructing Non-Locs.
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//===----------------------------------------------------------------------===//
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NonLoc NonLoc::MakeVal(SymbolRef sym) {
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return nonloc::SymbolVal(sym);
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}
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NonLoc NonLoc::MakeVal(SymbolManager& SymMgr, const SymExpr *lhs,
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BinaryOperator::Opcode op, const APSInt& v, QualType T) {
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// The Environment ensures we always get a persistent APSInt in
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// BasicValueFactory, so we don't need to get the APSInt from
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// BasicValueFactory again.
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assert(!Loc::IsLocType(T));
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return nonloc::SymExprVal(SymMgr.getSymIntExpr(lhs, op, v, T));
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}
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NonLoc NonLoc::MakeVal(SymbolManager& SymMgr, const SymExpr *lhs,
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BinaryOperator::Opcode op, const SymExpr *rhs,
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QualType T) {
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assert(SymMgr.getType(lhs) == SymMgr.getType(rhs));
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assert(!Loc::IsLocType(T));
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return nonloc::SymExprVal(SymMgr.getSymSymExpr(lhs, op, rhs, T));
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}
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NonLoc NonLoc::MakeIntVal(BasicValueFactory& BasicVals, uint64_t X,
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bool isUnsigned) {
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return nonloc::ConcreteInt(BasicVals.getIntValue(X, isUnsigned));
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}
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NonLoc NonLoc::MakeVal(BasicValueFactory& BasicVals, uint64_t X,
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unsigned BitWidth, bool isUnsigned) {
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return nonloc::ConcreteInt(BasicVals.getValue(X, BitWidth, isUnsigned));
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}
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NonLoc NonLoc::MakeVal(BasicValueFactory& BasicVals, uint64_t X, QualType T) {
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return nonloc::ConcreteInt(BasicVals.getValue(X, T));
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}
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NonLoc NonLoc::MakeVal(BasicValueFactory& BasicVals, IntegerLiteral* I) {
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return nonloc::ConcreteInt(BasicVals.getValue(APSInt(I->getValue(),
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I->getType()->isUnsignedIntegerType())));
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}
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NonLoc NonLoc::MakeVal(BasicValueFactory& BasicVals, const llvm::APInt& I,
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bool isUnsigned) {
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return nonloc::ConcreteInt(BasicVals.getValue(I, isUnsigned));
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}
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NonLoc NonLoc::MakeVal(BasicValueFactory& BasicVals, const llvm::APSInt& I) {
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return nonloc::ConcreteInt(BasicVals.getValue(I));
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}
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NonLoc NonLoc::MakeIntTruthVal(BasicValueFactory& BasicVals, bool b) {
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return nonloc::ConcreteInt(BasicVals.getTruthValue(b));
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}
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NonLoc NonLoc::MakeCompoundVal(QualType T, llvm::ImmutableList<SVal> Vals,
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BasicValueFactory& BasicVals) {
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return nonloc::CompoundVal(BasicVals.getCompoundValData(T, Vals));
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}
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SVal SVal::GetRValueSymbolVal(SymbolManager& SymMgr, MemRegionManager& MRMgr,
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const MemRegion* R) {
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SymbolRef sym = SymMgr.getRegionRValueSymbol(R);
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if (const TypedRegion* TR = dyn_cast<TypedRegion>(R)) {
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QualType T = TR->getRValueType(SymMgr.getContext());
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if (Loc::IsLocType(T))
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return Loc::MakeVal(MRMgr.getSymbolicRegion(sym));
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// Only handle integers for now.
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if (T->isIntegerType() && T->isScalarType())
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return NonLoc::MakeVal(sym);
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}
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return UnknownVal();
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}
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SVal SVal::GetConjuredSymbolVal(SymbolManager &SymMgr, MemRegionManager& MRMgr,
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const Expr* E, unsigned Count) {
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QualType T = E->getType();
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SymbolRef sym = SymMgr.getConjuredSymbol(E, Count);
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if (Loc::IsLocType(T))
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return Loc::MakeVal(MRMgr.getSymbolicRegion(sym));
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if (T->isIntegerType() && T->isScalarType())
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return NonLoc::MakeVal(sym);
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return UnknownVal();
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}
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SVal SVal::GetConjuredSymbolVal(SymbolManager &SymMgr, MemRegionManager& MRMgr,
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const Expr* E, QualType T, unsigned Count) {
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SymbolRef sym = SymMgr.getConjuredSymbol(E, T, Count);
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if (Loc::IsLocType(T))
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return Loc::MakeVal(MRMgr.getSymbolicRegion(sym));
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if (T->isIntegerType() && T->isScalarType())
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return NonLoc::MakeVal(sym);
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return UnknownVal();
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}
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nonloc::LocAsInteger nonloc::LocAsInteger::Make(BasicValueFactory& Vals, Loc V,
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unsigned Bits) {
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return LocAsInteger(Vals.getPersistentSValWithData(V, Bits));
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}
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//===----------------------------------------------------------------------===//
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// Utility methods for constructing Locs.
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//===----------------------------------------------------------------------===//
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Loc Loc::MakeVal(const MemRegion* R) { return loc::MemRegionVal(R); }
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Loc Loc::MakeVal(AddrLabelExpr* E) { return loc::GotoLabel(E->getLabel()); }
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Loc Loc::MakeNull(BasicValueFactory &BasicVals) {
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return loc::ConcreteInt(BasicVals.getZeroWithPtrWidth());
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}
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//===----------------------------------------------------------------------===//
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// Pretty-Printing.
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//===----------------------------------------------------------------------===//
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void SVal::printStdErr() const { print(llvm::errs()); }
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void SVal::print(std::ostream& Out) const {
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llvm::raw_os_ostream out(Out);
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print(out);
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}
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void SVal::print(llvm::raw_ostream& Out) const {
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switch (getBaseKind()) {
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case UnknownKind:
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Out << "Invalid"; break;
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case NonLocKind:
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cast<NonLoc>(this)->print(Out); break;
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case LocKind:
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cast<Loc>(this)->print(Out); break;
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case UndefinedKind:
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Out << "Undefined"; break;
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default:
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assert (false && "Invalid SVal.");
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}
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}
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void NonLoc::print(llvm::raw_ostream& Out) const {
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switch (getSubKind()) {
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case nonloc::ConcreteIntKind:
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Out << cast<nonloc::ConcreteInt>(this)->getValue().getZExtValue();
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if (cast<nonloc::ConcreteInt>(this)->getValue().isUnsigned())
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Out << 'U';
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break;
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case nonloc::SymbolValKind:
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Out << '$' << cast<nonloc::SymbolVal>(this)->getSymbol();
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break;
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case nonloc::SymExprValKind: {
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const nonloc::SymExprVal& C = *cast<nonloc::SymExprVal>(this);
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const SymExpr *SE = C.getSymbolicExpression();
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Out << SE;
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break;
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}
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case nonloc::LocAsIntegerKind: {
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const nonloc::LocAsInteger& C = *cast<nonloc::LocAsInteger>(this);
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C.getLoc().print(Out);
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Out << " [as " << C.getNumBits() << " bit integer]";
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break;
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}
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case nonloc::CompoundValKind: {
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const nonloc::CompoundVal& C = *cast<nonloc::CompoundVal>(this);
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Out << " {";
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bool first = true;
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for (nonloc::CompoundVal::iterator I=C.begin(), E=C.end(); I!=E; ++I) {
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if (first) { Out << ' '; first = false; }
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else Out << ", ";
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(*I).print(Out);
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}
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Out << " }";
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break;
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}
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default:
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assert (false && "Pretty-printed not implemented for this NonLoc.");
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break;
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}
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}
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void Loc::print(llvm::raw_ostream& Out) const {
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switch (getSubKind()) {
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case loc::ConcreteIntKind:
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Out << cast<loc::ConcreteInt>(this)->getValue().getZExtValue()
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<< " (Loc)";
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break;
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case loc::SymbolValKind:
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Out << '$' << cast<loc::SymbolVal>(this)->getSymbol();
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break;
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case loc::GotoLabelKind:
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Out << "&&"
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<< cast<loc::GotoLabel>(this)->getLabel()->getID()->getName();
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break;
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case loc::MemRegionKind:
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Out << '&' << cast<loc::MemRegionVal>(this)->getRegion()->getString();
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break;
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case loc::FuncValKind:
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Out << "function "
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<< cast<loc::FuncVal>(this)->getDecl()->getIdentifier()->getName();
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break;
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default:
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assert (false && "Pretty-printing not implemented for this Loc.");
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break;
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}
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}
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