Added "symbol iterators" for RValues, allowing easy iteration over the symbols
referenced by an RValue, instead of having to query the type of the RValue.

Modified ValueState::RemoveDeadBindings to also prune dead symbols.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@47142 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/Analysis/RValues.cpp b/Analysis/RValues.cpp
index 8d16f12..8eb607c 100644
--- a/Analysis/RValues.cpp
+++ b/Analysis/RValues.cpp
@@ -123,8 +123,32 @@
   return *C;
 }
 
+//===----------------------------------------------------------------------===//
+// Symbol Iteration.
+//===----------------------------------------------------------------------===//
 
- 
+RValue::symbol_iterator RValue::symbol_begin() const {
+  if (isa<LValue>(this)) {
+    if (isa<lval::SymbolVal>(this))
+      return (symbol_iterator) (&Data);
+  }
+  else {
+    if (isa<nonlval::SymbolVal>(this))
+      return (symbol_iterator) (&Data);
+    else if (isa<nonlval::SymIntConstraintVal>(this)) {
+      const SymIntConstraint& C =
+        cast<nonlval::SymIntConstraintVal>(this)->getConstraint();
+      return (symbol_iterator) &C.getSymbol();
+    }
+  }
+  
+  return NULL;
+}
+
+RValue::symbol_iterator RValue::symbol_end() const {
+  symbol_iterator X = symbol_begin();
+  return X ? X+1 : NULL;
+}
 
 //===----------------------------------------------------------------------===//
 // Transfer function dispatch for Non-LValues.
diff --git a/Analysis/ValueState.cpp b/Analysis/ValueState.cpp
index c74c876..27818ef 100644
--- a/Analysis/ValueState.cpp
+++ b/Analysis/ValueState.cpp
@@ -12,6 +12,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "ValueState.h"
+#include "llvm/ADT/SmallSet.h"
 
 using namespace clang;
 
@@ -43,6 +44,8 @@
   // for optimum performance.
   
   llvm::SmallVector<ValueDecl*, 10> WList;
+  llvm::SmallPtrSet<ValueDecl*, 10> Marked;  
+  llvm::SmallSet<SymbolID, 20> MarkedSymbols;
   
   ValueStateImpl NewSt = *St;
   
@@ -55,10 +58,16 @@
     Expr* BlkExpr = I.getKey();
     
     if (Liveness.isLive(Loc, BlkExpr)) {
-      if (isa<lval::DeclVal>(I.getData())) {
-        lval::DeclVal LV = cast<lval::DeclVal>(I.getData());
+      RValue X = I.getData();
+      
+      if (isa<lval::DeclVal>(X)) {
+        lval::DeclVal LV = cast<lval::DeclVal>(X);
         WList.push_back(LV.getDecl());
       }
+      
+      for (RValue::symbol_iterator SI=X.symbol_begin(), SE=X.symbol_end();
+                                   SI != SE; ++SI)
+        MarkedSymbols.insert(*SI);      
     }
     else
       NewSt.BlockExprBindings = Remove(NewSt, BlkExpr);
@@ -70,8 +79,7 @@
   for (ValueState::vb_iterator I = St.vb_begin(), E = St.vb_end(); I!=E ; ++I)
     if (Liveness.isLive(Loc, I.getKey()))
       WList.push_back(I.getKey());
-  
-  llvm::SmallPtrSet<ValueDecl*, 10> Marked;  
+
   
   while (!WList.empty()) {
     ValueDecl* V = WList.back();
@@ -83,7 +91,11 @@
     Marked.insert(V);
     
     if (V->getType()->isPointerType()) {
-      const LValue& LV = cast<LValue>(GetValue(St, lval::DeclVal(V)));
+      const LValue& LV = cast<LValue>(GetValue(St, lval::DeclVal(V)));      
+      
+      for (RValue::symbol_iterator SI=LV.symbol_begin(), SE=LV.symbol_end();
+           SI != SE; ++SI)
+        MarkedSymbols.insert(*SI); 
       
       if (!isa<lval::DeclVal>(LV))
         continue;
@@ -93,10 +105,20 @@
     }    
   }
   
+  // Remove dead variable bindings.
   for (ValueState::vb_iterator I = St.vb_begin(), E = St.vb_end(); I!=E ; ++I)
     if (!Marked.count(I.getKey()))
       NewSt.VarBindings = Remove(NewSt, I.getKey());
   
+  // Remove dead symbols.
+  for (ValueState::ce_iterator I = St.ce_begin(), E=St.ce_end(); I!=E; ++I)
+    if (!MarkedSymbols.count(I.getKey()))
+      NewSt.ConstantEq = CEFactory.Remove(NewSt.ConstantEq, I.getKey());
+  
+  for (ValueState::cne_iterator I = St.cne_begin(), E=St.cne_end(); I!=E; ++I)
+    if (!MarkedSymbols.count(I.getKey()))
+      NewSt.ConstantNotEq = CNEFactory.Remove(NewSt.ConstantNotEq, I.getKey());
+  
   return getPersistentState(NewSt);
 }
 
diff --git a/Analysis/ValueState.h b/Analysis/ValueState.h
index c0bc81d..38c34cb 100644
--- a/Analysis/ValueState.h
+++ b/Analysis/ValueState.h
@@ -153,6 +153,14 @@
   beb_iterator beb_begin() const { return Data->BlockExprBindings.begin(); }
   beb_iterator beb_end() const { return Data->BlockExprBindings.end(); }
   
+  typedef ConstantNotEqTy::iterator cne_iterator;
+  cne_iterator cne_begin() const { return Data->ConstantNotEq.begin(); }
+  cne_iterator cne_end() const { return Data->ConstantNotEq.end(); }
+  
+  typedef ConstantEqTy::iterator ce_iterator;
+  ce_iterator ce_begin() const { return Data->ConstantEq.begin(); }
+  ce_iterator ce_end() const { return Data->ConstantEq.end(); }
+  
   // Profiling and equality testing.
   
   bool operator==(const ValueState& RHS) const {