/// Scan all symbols referenced by the constraints. If the symbol is not alive
/// as marked in LSymbols, mark it as dead in DSymbols.
ProgramStateRef
BasicConstraintManager::removeDeadBindings(ProgramStateRef state,
SymbolReaper& SymReaper) {
ConstEqTy CE = state->get<ConstEq>();
ConstEqTy::Factory& CEFactory = state->get_context<ConstEq>();
for (ConstEqTy::iterator I = CE.begin(), E = CE.end(); I!=E; ++I) {
SymbolRef sym = I.getKey();
if (SymReaper.maybeDead(sym))
CE = CEFactory.remove(CE, sym);
}
state = state->set<ConstEq>(CE);
ConstNotEqTy CNE = state->get<ConstNotEq>();
ConstNotEqTy::Factory& CNEFactory = state->get_context<ConstNotEq>();
for (ConstNotEqTy::iterator I = CNE.begin(), E = CNE.end(); I != E; ++I) {
SymbolRef sym = I.getKey();
if (SymReaper.maybeDead(sym))
CNE = CNEFactory.remove(CNE, sym);
}
return state->set<ConstNotEq>(CNE);
}
/// Scan all symbols referenced by the constraints. If the symbol is not alive
/// as marked in LSymbols, mark it as dead in DSymbols.
ProgramStateRef
RangeConstraintManager::removeDeadBindings(ProgramStateRef state,
SymbolReaper& SymReaper) {
ConstraintRangeTy CR = state->get<ConstraintRange>();
ConstraintRangeTy::Factory& CRFactory = state->get_context<ConstraintRange>();
for (ConstraintRangeTy::iterator I = CR.begin(), E = CR.end(); I != E; ++I) {
SymbolRef sym = I.getKey();
if (SymReaper.maybeDead(sym))
CR = CRFactory.remove(CR, sym);
}
return state->set<ConstraintRange>(CR);
}
/// Scan all symbols referenced by the constraints. If the symbol is not alive
/// as marked in LSymbols, mark it as dead in DSymbols.
ProgramStateRef
RangeConstraintManager::removeDeadBindings(ProgramStateRef State,
SymbolReaper &SymReaper) {
bool Changed = false;
ConstraintRangeTy CR = State->get<ConstraintRange>();
ConstraintRangeTy::Factory &CRFactory = State->get_context<ConstraintRange>();
for (ConstraintRangeTy::iterator I = CR.begin(), E = CR.end(); I != E; ++I) {
SymbolRef Sym = I.getKey();
if (SymReaper.maybeDead(Sym)) {
Changed = true;
CR = CRFactory.remove(CR, Sym);
}
}
return Changed ? State->set<ConstraintRange>(CR) : State;
}
// removeDeadBindings:
// - Remove subexpression bindings.
// - Remove dead block expression bindings.
// - Keep live block expression bindings:
// - Mark their reachable symbols live in SymbolReaper,
// see ScanReachableSymbols.
// - Mark the region in DRoots if the binding is a loc::MemRegionVal.
Environment
EnvironmentManager::removeDeadBindings(Environment Env,
SymbolReaper &SymReaper,
ProgramStateRef ST) {
// We construct a new Environment object entirely, as this is cheaper than
// individually removing all the subexpression bindings (which will greatly
// outnumber block-level expression bindings).
Environment NewEnv = getInitialEnvironment();
MarkLiveCallback CB(SymReaper);
ScanReachableSymbols RSScaner(ST, CB);
llvm::ImmutableMapRef<EnvironmentEntry,SVal>
EBMapRef(NewEnv.ExprBindings.getRootWithoutRetain(),
F.getTreeFactory());
// Iterate over the block-expr bindings.
for (Environment::iterator I = Env.begin(), E = Env.end();
I != E; ++I) {
const EnvironmentEntry &BlkExpr = I.getKey();
const SVal &X = I.getData();
if (SymReaper.isLive(BlkExpr.getStmt(), BlkExpr.getLocationContext())) {
// Copy the binding to the new map.
EBMapRef = EBMapRef.add(BlkExpr, X);
// If the block expr's value is a memory region, then mark that region.
if (Optional<loc::MemRegionVal> R = X.getAs<loc::MemRegionVal>())
SymReaper.markLive(R->getRegion());
// Mark all symbols in the block expr's value live.
RSScaner.scan(X);
continue;
} else {
SymExpr::symbol_iterator SI = X.symbol_begin(), SE = X.symbol_end();
for (; SI != SE; ++SI)
SymReaper.maybeDead(*SI);
}
}
NewEnv.ExprBindings = EBMapRef.asImmutableMap();
return NewEnv;
}
Store BasicStoreManager::RemoveDeadBindings(Store store, Stmt* Loc,
SymbolReaper& SymReaper,
llvm::SmallVectorImpl<const MemRegion*>& RegionRoots)
{
BindingsTy B = GetBindings(store);
typedef SVal::symbol_iterator symbol_iterator;
// Iterate over the variable bindings.
for (BindingsTy::iterator I=B.begin(), E=B.end(); I!=E ; ++I) {
if (const VarRegion *VR = dyn_cast<VarRegion>(I.getKey())) {
if (SymReaper.isLive(Loc, VR))
RegionRoots.push_back(VR);
else
continue;
}
else if (isa<ObjCIvarRegion>(I.getKey())) {
RegionRoots.push_back(I.getKey());
}
else
continue;
// Mark the bindings in the data as live.
SVal X = I.getData();
for (symbol_iterator SI=X.symbol_begin(), SE=X.symbol_end(); SI!=SE; ++SI)
SymReaper.markLive(*SI);
}
// Scan for live variables and live symbols.
llvm::SmallPtrSet<const MemRegion*, 10> Marked;
while (!RegionRoots.empty()) {
const MemRegion* MR = RegionRoots.back();
RegionRoots.pop_back();
while (MR) {
if (const SymbolicRegion* SymR = dyn_cast<SymbolicRegion>(MR)) {
SymReaper.markLive(SymR->getSymbol());
break;
}
else if (isa<VarRegion>(MR) || isa<ObjCIvarRegion>(MR)) {
if (Marked.count(MR))
break;
Marked.insert(MR);
SVal X = Retrieve(store, loc::MemRegionVal(MR));
// FIXME: We need to handle symbols nested in region definitions.
for (symbol_iterator SI=X.symbol_begin(),SE=X.symbol_end(); SI!=SE; ++SI)
SymReaper.markLive(*SI);
if (!isa<loc::MemRegionVal>(X))
break;
const loc::MemRegionVal& LVD = cast<loc::MemRegionVal>(X);
RegionRoots.push_back(LVD.getRegion());
break;
}
else if (const SubRegion* R = dyn_cast<SubRegion>(MR))
MR = R->getSuperRegion();
else
break;
}
}
// Remove dead variable bindings.
for (BindingsTy::iterator I=B.begin(), E=B.end(); I!=E ; ++I) {
const MemRegion* R = I.getKey();
if (!Marked.count(R)) {
store = Remove(store, ValMgr.makeLoc(R));
SVal X = I.getData();
for (symbol_iterator SI=X.symbol_begin(), SE=X.symbol_end(); SI!=SE; ++SI)
SymReaper.maybeDead(*SI);
}
}
return store;
}
