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