Check in LLVM r95781.
diff --git a/lib/Checker/Environment.cpp b/lib/Checker/Environment.cpp
new file mode 100644
index 0000000..c2c9190
--- /dev/null
+++ b/lib/Checker/Environment.cpp
@@ -0,0 +1,164 @@
+//== Environment.cpp - Map from Stmt* to Locations/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 defined the Environment and EnvironmentManager classes.
+//
+//===----------------------------------------------------------------------===//
+#include "clang/Checker/PathSensitive/GRState.h"
+#include "clang/Analysis/Analyses/LiveVariables.h"
+#include "llvm/ADT/ImmutableMap.h"
+
+using namespace clang;
+
+SVal Environment::GetSVal(const Stmt *E, ValueManager& ValMgr) const {
+
+ for (;;) {
+
+ switch (E->getStmtClass()) {
+
+ case Stmt::AddrLabelExprClass:
+ return ValMgr.makeLoc(cast<AddrLabelExpr>(E));
+
+ // ParenExprs are no-ops.
+
+ case Stmt::ParenExprClass:
+ E = cast<ParenExpr>(E)->getSubExpr();
+ continue;
+
+ case Stmt::CharacterLiteralClass: {
+ const CharacterLiteral* C = cast<CharacterLiteral>(E);
+ return ValMgr.makeIntVal(C->getValue(), C->getType());
+ }
+
+ case Stmt::IntegerLiteralClass: {
+ // In C++, this expression may have been bound to a temporary object.
+ SVal const *X = ExprBindings.lookup(E);
+ if (X)
+ return *X;
+ else
+ return ValMgr.makeIntVal(cast<IntegerLiteral>(E));
+ }
+
+ // Casts where the source and target type are the same
+ // are no-ops. We blast through these to get the descendant
+ // subexpression that has a value.
+
+ case Stmt::ImplicitCastExprClass:
+ case Stmt::CStyleCastExprClass: {
+ const CastExpr* C = cast<CastExpr>(E);
+ QualType CT = C->getType();
+
+ if (CT->isVoidType())
+ return UnknownVal();
+
+ break;
+ }
+
+ // Handle all other Stmt* using a lookup.
+
+ default:
+ break;
+ };
+
+ break;
+ }
+
+ return LookupExpr(E);
+}
+
+Environment EnvironmentManager::BindExpr(Environment Env, const Stmt *S,
+ SVal V, bool Invalidate) {
+ assert(S);
+
+ if (V.isUnknown()) {
+ if (Invalidate)
+ return Environment(F.Remove(Env.ExprBindings, S), Env.ACtx);
+ else
+ return Env;
+ }
+
+ return Environment(F.Add(Env.ExprBindings, S, V), Env.ACtx);
+}
+
+namespace {
+class MarkLiveCallback : public SymbolVisitor {
+ SymbolReaper &SymReaper;
+public:
+ MarkLiveCallback(SymbolReaper &symreaper) : SymReaper(symreaper) {}
+ bool VisitSymbol(SymbolRef sym) { SymReaper.markLive(sym); return true; }
+};
+} // end anonymous namespace
+
+// 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, const Stmt *S,
+ SymbolReaper &SymReaper,
+ const GRState *ST,
+ llvm::SmallVectorImpl<const MemRegion*> &DRoots) {
+
+ CFG &C = *Env.getAnalysisContext().getCFG();
+
+ // 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(&Env.getAnalysisContext());
+
+ // Iterate over the block-expr bindings.
+ for (Environment::iterator I = Env.begin(), E = Env.end();
+ I != E; ++I) {
+
+ const Stmt *BlkExpr = I.getKey();
+
+ // Not a block-level expression?
+ if (!C.isBlkExpr(BlkExpr))
+ continue;
+
+ const SVal &X = I.getData();
+
+ if (SymReaper.isLive(S, BlkExpr)) {
+ // Copy the binding to the new map.
+ NewEnv.ExprBindings = F.Add(NewEnv.ExprBindings, BlkExpr, X);
+
+ // If the block expr's value is a memory region, then mark that region.
+ if (isa<loc::MemRegionVal>(X)) {
+ const MemRegion* R = cast<loc::MemRegionVal>(X).getRegion();
+ DRoots.push_back(R);
+ // Mark the super region of the RX as live.
+ // e.g.: int x; char *y = (char*) &x; if (*y) ...
+ // 'y' => element region. 'x' is its super region.
+ // We only add one level super region for now.
+
+ // FIXME: maybe multiple level of super regions should be added.
+ if (const SubRegion *SR = dyn_cast<SubRegion>(R))
+ DRoots.push_back(SR->getSuperRegion());
+ }
+
+ // Mark all symbols in the block expr's value live.
+ MarkLiveCallback cb(SymReaper);
+ ST->scanReachableSymbols(X, cb);
+ continue;
+ }
+
+ // Otherwise the expression is dead with a couple exceptions.
+ // Do not misclean LogicalExpr or ConditionalOperator. It is dead at the
+ // beginning of itself, but we need its UndefinedVal to determine its
+ // SVal.
+ if (X.isUndef() && cast<UndefinedVal>(X).getData())
+ NewEnv.ExprBindings = F.Add(NewEnv.ExprBindings, BlkExpr, X);
+ }
+
+ return NewEnv;
+}