352 lines
10 KiB
C++
352 lines
10 KiB
C++
//= GRState.cpp - Path-Sensitive "State" for tracking values -----*- 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 implements GRState and GRStateManager.
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//
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//===----------------------------------------------------------------------===//
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#include "clang/Analysis/PathSensitive/GRStateTrait.h"
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#include "clang/Analysis/PathSensitive/GRState.h"
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#include "clang/Analysis/PathSensitive/GRTransferFuncs.h"
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#include "llvm/ADT/SmallSet.h"
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#include "llvm/Support/raw_ostream.h"
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using namespace clang;
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// Give the vtable for ConstraintManager somewhere to live.
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// FIXME: Move this elsewhere.
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ConstraintManager::~ConstraintManager() {}
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GRStateManager::~GRStateManager() {
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for (std::vector<GRState::Printer*>::iterator I=Printers.begin(),
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E=Printers.end(); I!=E; ++I)
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delete *I;
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for (GDMContextsTy::iterator I=GDMContexts.begin(), E=GDMContexts.end();
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I!=E; ++I)
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I->second.second(I->second.first);
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}
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const GRState*
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GRStateManager::RemoveDeadBindings(const GRState* state, Stmt* Loc,
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SymbolReaper& SymReaper) {
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// This code essentially performs a "mark-and-sweep" of the VariableBindings.
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// The roots are any Block-level exprs and Decls that our liveness algorithm
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// tells us are live. We then see what Decls they may reference, and keep
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// those around. This code more than likely can be made faster, and the
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// frequency of which this method is called should be experimented with
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// for optimum performance.
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llvm::SmallVector<const MemRegion*, 10> RegionRoots;
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GRState NewState = *state;
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NewState.Env = EnvMgr.RemoveDeadBindings(NewState.Env, Loc, SymReaper, *this,
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state, RegionRoots);
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// Clean up the store.
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StoreMgr->RemoveDeadBindings(NewState, Loc, SymReaper, RegionRoots);
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return ConstraintMgr->RemoveDeadBindings(getPersistentState(NewState),
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SymReaper);
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}
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const GRState *GRState::unbindLoc(Loc LV) const {
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Store OldStore = getStore();
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Store NewStore = Mgr->StoreMgr->Remove(OldStore, LV);
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if (NewStore == OldStore)
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return this;
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GRState NewSt = *this;
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NewSt.St = NewStore;
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return Mgr->getPersistentState(NewSt);
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}
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SVal GRState::getSValAsScalarOrLoc(const MemRegion *R) const {
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// We only want to do fetches from regions that we can actually bind
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// values. For example, SymbolicRegions of type 'id<...>' cannot
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// have direct bindings (but their can be bindings on their subregions).
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if (!R->isBoundable())
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return UnknownVal();
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if (const TypedRegion *TR = dyn_cast<TypedRegion>(R)) {
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QualType T = TR->getValueType(Mgr->getContext());
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if (Loc::IsLocType(T) || T->isIntegerType())
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return getSVal(R);
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}
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return UnknownVal();
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}
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const GRState *GRState::bindExpr(const Stmt* Ex, SVal V, bool isBlkExpr,
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bool Invalidate) const {
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Environment NewEnv = Mgr->EnvMgr.BindExpr(Env, Ex, V, isBlkExpr, Invalidate);
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if (NewEnv == Env)
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return this;
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GRState NewSt = *this;
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NewSt.Env = NewEnv;
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return Mgr->getPersistentState(NewSt);
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}
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const GRState *GRState::bindExpr(const Stmt* Ex, SVal V,
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bool Invalidate) const {
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bool isBlkExpr = false;
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if (Ex == Mgr->CurrentStmt) {
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// FIXME: Should this just be an assertion? When would we want to set
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// the value of a block-level expression if it wasn't CurrentStmt?
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isBlkExpr = Mgr->cfg.isBlkExpr(Ex);
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if (!isBlkExpr)
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return this;
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}
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return bindExpr(Ex, V, isBlkExpr, Invalidate);
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}
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const GRState* GRStateManager::getInitialState() {
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GRState StateImpl(this, EnvMgr.getInitialEnvironment(),
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StoreMgr->getInitialStore(),
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GDMFactory.GetEmptyMap());
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return getPersistentState(StateImpl);
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}
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const GRState* GRStateManager::getPersistentState(GRState& State) {
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llvm::FoldingSetNodeID ID;
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State.Profile(ID);
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void* InsertPos;
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if (GRState* I = StateSet.FindNodeOrInsertPos(ID, InsertPos))
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return I;
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GRState* I = (GRState*) Alloc.Allocate<GRState>();
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new (I) GRState(State);
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StateSet.InsertNode(I, InsertPos);
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return I;
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}
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const GRState* GRState::makeWithStore(Store store) const {
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GRState NewSt = *this;
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NewSt.St = store;
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return Mgr->getPersistentState(NewSt);
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}
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//===----------------------------------------------------------------------===//
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// State pretty-printing.
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//===----------------------------------------------------------------------===//
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void GRState::print(llvm::raw_ostream& Out, const char* nl,
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const char* sep) const {
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// Print the store.
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Mgr->getStoreManager().print(getStore(), Out, nl, sep);
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// Print Subexpression bindings.
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bool isFirst = true;
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for (seb_iterator I = seb_begin(), E = seb_end(); I != E; ++I) {
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if (isFirst) {
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Out << nl << nl << "Sub-Expressions:" << nl;
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isFirst = false;
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}
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else { Out << nl; }
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Out << " (" << (void*) I.getKey() << ") ";
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LangOptions LO; // FIXME.
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I.getKey()->printPretty(Out, 0, PrintingPolicy(LO));
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Out << " : " << I.getData();
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}
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// Print block-expression bindings.
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isFirst = true;
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for (beb_iterator I = beb_begin(), E = beb_end(); I != E; ++I) {
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if (isFirst) {
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Out << nl << nl << "Block-level Expressions:" << nl;
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isFirst = false;
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}
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else { Out << nl; }
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Out << " (" << (void*) I.getKey() << ") ";
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LangOptions LO; // FIXME.
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I.getKey()->printPretty(Out, 0, PrintingPolicy(LO));
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Out << " : " << I.getData();
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}
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Mgr->getConstraintManager().print(this, Out, nl, sep);
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// Print checker-specific data.
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for (std::vector<Printer*>::iterator I = Mgr->Printers.begin(),
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E = Mgr->Printers.end(); I != E; ++I) {
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(*I)->Print(Out, this, nl, sep);
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}
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}
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void GRState::printDOT(llvm::raw_ostream& Out) const {
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print(Out, "\\l", "\\|");
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}
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void GRState::printStdErr() const {
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print(llvm::errs());
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}
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//===----------------------------------------------------------------------===//
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// Generic Data Map.
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//===----------------------------------------------------------------------===//
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void* const* GRState::FindGDM(void* K) const {
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return GDM.lookup(K);
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}
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void*
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GRStateManager::FindGDMContext(void* K,
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void* (*CreateContext)(llvm::BumpPtrAllocator&),
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void (*DeleteContext)(void*)) {
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std::pair<void*, void (*)(void*)>& p = GDMContexts[K];
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if (!p.first) {
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p.first = CreateContext(Alloc);
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p.second = DeleteContext;
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}
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return p.first;
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}
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const GRState* GRStateManager::addGDM(const GRState* St, void* Key, void* Data){
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GRState::GenericDataMap M1 = St->getGDM();
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GRState::GenericDataMap M2 = GDMFactory.Add(M1, Key, Data);
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if (M1 == M2)
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return St;
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GRState NewSt = *St;
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NewSt.GDM = M2;
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return getPersistentState(NewSt);
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}
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//===----------------------------------------------------------------------===//
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// Utility.
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//===----------------------------------------------------------------------===//
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namespace {
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class VISIBILITY_HIDDEN ScanReachableSymbols : public SubRegionMap::Visitor {
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typedef llvm::DenseSet<const MemRegion*> VisitedRegionsTy;
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VisitedRegionsTy visited;
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const GRState *state;
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SymbolVisitor &visitor;
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llvm::OwningPtr<SubRegionMap> SRM;
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public:
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ScanReachableSymbols(const GRState *st, SymbolVisitor& v)
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: state(st), visitor(v) {}
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bool scan(nonloc::CompoundVal val);
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bool scan(SVal val);
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bool scan(const MemRegion *R);
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// From SubRegionMap::Visitor.
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bool Visit(const MemRegion* Parent, const MemRegion* SubRegion) {
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return scan(SubRegion);
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}
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};
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}
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bool ScanReachableSymbols::scan(nonloc::CompoundVal val) {
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for (nonloc::CompoundVal::iterator I=val.begin(), E=val.end(); I!=E; ++I)
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if (!scan(*I))
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return false;
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return true;
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}
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bool ScanReachableSymbols::scan(SVal val) {
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if (loc::MemRegionVal *X = dyn_cast<loc::MemRegionVal>(&val))
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return scan(X->getRegion());
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if (SymbolRef Sym = val.getAsSymbol())
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return visitor.VisitSymbol(Sym);
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if (nonloc::CompoundVal *X = dyn_cast<nonloc::CompoundVal>(&val))
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return scan(*X);
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return true;
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}
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bool ScanReachableSymbols::scan(const MemRegion *R) {
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if (isa<MemSpaceRegion>(R) || visited.count(R))
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return true;
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visited.insert(R);
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// If this is a symbolic region, visit the symbol for the region.
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if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R))
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if (!visitor.VisitSymbol(SR->getSymbol()))
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return false;
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// If this is a subregion, also visit the parent regions.
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if (const SubRegion *SR = dyn_cast<SubRegion>(R))
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if (!scan(SR->getSuperRegion()))
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return false;
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// Now look at the binding to this region (if any).
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if (!scan(state->getSValAsScalarOrLoc(R)))
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return false;
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// Now look at the subregions.
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if (!SRM.get())
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SRM.reset(state->getStateManager().getStoreManager().getSubRegionMap(state));
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return SRM->iterSubRegions(R, *this);
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}
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bool GRState::scanReachableSymbols(SVal val, SymbolVisitor& visitor) const {
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ScanReachableSymbols S(this, visitor);
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return S.scan(val);
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}
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//===----------------------------------------------------------------------===//
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// Queries.
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//===----------------------------------------------------------------------===//
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bool GRStateManager::isEqual(const GRState* state, const Expr* Ex,
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const llvm::APSInt& Y) {
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SVal V = state->getSVal(Ex);
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if (loc::ConcreteInt* X = dyn_cast<loc::ConcreteInt>(&V))
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return X->getValue() == Y;
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if (nonloc::ConcreteInt* X = dyn_cast<nonloc::ConcreteInt>(&V))
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return X->getValue() == Y;
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if (SymbolRef Sym = V.getAsSymbol())
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return ConstraintMgr->isEqual(state, Sym, Y);
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return false;
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}
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bool GRStateManager::isEqual(const GRState* state, const Expr* Ex, uint64_t x) {
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return isEqual(state, Ex, getBasicVals().getValue(x, Ex->getType()));
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}
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//===----------------------------------------------------------------------===//
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// Persistent values for indexing into the Generic Data Map.
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int GRState::NullDerefTag::TagInt = 0;
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