Added several guards in transfer functions for "InvalidValues".
Fixed bug in RemoveDeadBindings by implementing a simple "mark-and-sweep"
cleaner over the bindings, starting from the Decls and block-level expressions
that are considered "live" by the Liveness analysis.
Fixed bug in isa<> implementation for class LValue.
Added "VisitDeclRefExpr" to GRConstants so that we explicitly bind the current
value of variable to the Block-level Expression (i.e., when the DeclRefExpr is
at the CFGBlock level).
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@46839 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/Analysis/GRConstants.cpp b/Analysis/GRConstants.cpp
index 65cb6e7..399dacc 100644
--- a/Analysis/GRConstants.cpp
+++ b/Analysis/GRConstants.cpp
@@ -257,7 +257,10 @@
void VisitBinaryOperator(BinaryOperator* B, NodeTy* Pred, NodeSet& Dst);
void VisitAssignmentLHS(Expr* E, NodeTy* Pred, NodeSet& Dst);
-
+
+ /// VisitDeclRefExpr - Transfer function logic for DeclRefExprs.
+ void VisitDeclRefExpr(DeclRefExpr* DR, NodeTy* Pred, NodeSet& Dst);
+
/// VisitDeclStmt - Transfer function logic for DeclStmts.
void VisitDeclStmt(DeclStmt* DS, NodeTy* Pred, NodeSet& Dst);
@@ -273,21 +276,21 @@
GRConstants::StateTy
GRConstants::SetValue(StateTy St, Stmt* S, const RValue& V) {
-
+
if (!StateCleaned) {
St = RemoveDeadBindings(CurrentStmt, St);
StateCleaned = true;
}
-
+
bool isBlkExpr = false;
-
+
if (S == CurrentStmt) {
isBlkExpr = getCFG().isBlkExpr(S);
if (!isBlkExpr)
return St;
}
-
+
return StateMgr.SetValue(St, S, isBlkExpr, V);
}
@@ -484,25 +487,73 @@
}
GRConstants::StateTy GRConstants::RemoveDeadBindings(Stmt* Loc, StateTy M) {
- // Note: in the code below, we can assign a new map to M since the
- // iterators are iterating over the tree of the *original* map.
- StateTy::vb_iterator I = M.begin(), E = M.end();
+
+ // 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<ValueDecl*, 10> WList;
- for (; I!=E && !I.getKey().isSymbol(); ++I) {
- // Remove old bindings for subexpressions and "dead"
- // block-level expressions.
- if (I.getKey().isSubExpr() ||
- I.getKey().isBlkExpr() && !Liveness.isLive(Loc,cast<Stmt>(I.getKey()))){
+ for (StateTy::vb_iterator I = M.begin(), E = M.end();
+ I!=E && !I.getKey().isSymbol(); ++I) {
+
+ // Remove old bindings for subexpressions.
+ if (I.getKey().isSubExpr()) {
M = StateMgr.Remove(M, I.getKey());
+ continue;
}
- else if (I.getKey().isDecl()) { // Remove bindings for "dead" decls.
- if (VarDecl* V = dyn_cast<VarDecl>(cast<ValueDecl>(I.getKey())))
- if (!Liveness.isLive(Loc, V))
- M = StateMgr.Remove(M, I.getKey());
+
+ if (I.getKey().isBlkExpr()) {
+ if (Liveness.isLive(Loc, cast<Stmt>(I.getKey()))) {
+ if (isa<lval::DeclVal>(I.getData())) {
+ lval::DeclVal LV = cast<lval::DeclVal>(I.getData());
+ WList.push_back(LV.getDecl());
+ }
+ }
+ else
+ M = StateMgr.Remove(M, I.getKey());
+
+ continue;
}
+
+ assert (I.getKey().isDecl());
+
+ if (VarDecl* V = dyn_cast<VarDecl>(cast<ValueDecl>(I.getKey())))
+ if (Liveness.isLive(Loc, V))
+ WList.push_back(V);
}
+ llvm::SmallPtrSet<ValueDecl*, 10> Marked;
+
+ while (!WList.empty()) {
+ ValueDecl* V = WList.back();
+ WList.pop_back();
+
+ if (Marked.count(V))
+ continue;
+
+ Marked.insert(V);
+
+ if (V->getType()->isPointerType()) {
+ const LValue& LV = cast<LValue>(GetValue(M, lval::DeclVal(V)));
+
+ if (!isa<lval::DeclVal>(LV))
+ continue;
+
+ const lval::DeclVal& LVD = cast<lval::DeclVal>(LV);
+ WList.push_back(LVD.getDecl());
+ }
+ }
+
+ for (StateTy::vb_iterator I = M.begin(), E = M.end(); I!=E ; ++I)
+ if (I.getKey().isDecl())
+ if (VarDecl* V = dyn_cast<VarDecl>(cast<ValueDecl>(I.getKey())))
+ if (!Marked.count(V))
+ M = StateMgr.Remove(M, V);
+
return M;
}
@@ -522,6 +573,21 @@
Nodify(Dst, S, Pred, *I);
}
+void GRConstants::VisitDeclRefExpr(DeclRefExpr* D, NodeTy* Pred, NodeSet& Dst) {
+ if (D != CurrentStmt) {
+ Dst.Add(Pred); // No-op. Simply propagate the current state unchanged.
+ return;
+ }
+
+ // If we are here, we are loading the value of the decl and binding
+ // it to the block-level expression.
+
+ StateTy St = Pred->getState();
+
+ Nodify(Dst, D, Pred,
+ SetValue(St, D, GetValue(St, lval::DeclVal(D->getDecl()))));
+}
+
void GRConstants::VisitCast(Expr* CastE, Expr* E, NodeTy* Pred, NodeSet& Dst) {
QualType T = CastE->getType();
@@ -576,8 +642,19 @@
void GRConstants::VisitUnaryOperator(UnaryOperator* U,
GRConstants::NodeTy* Pred,
GRConstants::NodeSet& Dst) {
+
NodeSet S1;
- Visit(U->getSubExpr(), Pred, S1);
+ UnaryOperator::Opcode Op = U->getOpcode();
+
+ // FIXME: This is a hack so that for '*' and '&' we don't recurse
+ // on visiting the subexpression if it is a DeclRefExpr. We should
+ // probably just handle AddrOf and Deref in their own methods to make
+ // this cleaner.
+ if ((Op == UnaryOperator::Deref || Op == UnaryOperator::AddrOf) &&
+ isa<DeclRefExpr>(U->getSubExpr()))
+ S1.Add(Pred);
+ else
+ Visit(U->getSubExpr(), Pred, S1);
for (NodeSet::iterator I1=S1.begin(), E1=S1.end(); I1 != E1; ++I1) {
NodeTy* N1 = *I1;
@@ -673,7 +750,12 @@
}
case UnaryOperator::Deref: {
- const LValue& L1 = cast<LValue>(GetValue(St, U->getSubExpr()));
+ // FIXME: Stop when dereferencing an uninitialized value.
+ // FIXME: Bifurcate when dereferencing a symbolic with no constraints?
+
+ const RValue& V = GetValue(St, U->getSubExpr());
+ const LValue& L1 = cast<LValue>(V);
+
Nodify(Dst, U, N1, SetValue(St, U, GetValue(St, L1)));
break;
}
@@ -687,8 +769,10 @@
void GRConstants::VisitAssignmentLHS(Expr* E, GRConstants::NodeTy* Pred,
GRConstants::NodeSet& Dst) {
- if (isa<DeclRefExpr>(E))
+ if (isa<DeclRefExpr>(E)) {
+ Dst.Add(Pred);
return;
+ }
if (UnaryOperator* U = dyn_cast<UnaryOperator>(E)) {
if (U->getOpcode() == UnaryOperator::Deref) {
@@ -754,6 +838,7 @@
}
continue;
+
}
switch (Op) {
@@ -826,6 +911,10 @@
case Stmt::ParenExprClass:
Visit(cast<ParenExpr>(S)->getSubExpr(), Pred, Dst);
break;
+
+ case Stmt::DeclRefExprClass:
+ VisitDeclRefExpr(cast<DeclRefExpr>(S), Pred, Dst);
+ break;
case Stmt::ImplicitCastExprClass: {
ImplicitCastExpr* C = cast<ImplicitCastExpr>(S);