From 1c64daba5bae3790429fc455a530e466a6a3a8cf Mon Sep 17 00:00:00 2001
From: Ted Kremenek <kremenek@apple.com>
Date: Wed, 27 Feb 2008 06:47:26 +0000
Subject: [PATCH] When analyzing a function, eagerly create symbolic values for
 all globals/parameters at the beginning of the analysis.

llvm-svn: 47664
---
 clang/Analysis/GRExprEngine.cpp               | 55 +++++++++----------
 clang/Analysis/ValueState.cpp                 |  6 +-
 .../Analysis/PathSensitive/GRExprEngine.h     | 11 +---
 .../clang/Analysis/PathSensitive/ValueState.h |  1 +
 4 files changed, 32 insertions(+), 41 deletions(-)

diff --git a/clang/Analysis/GRExprEngine.cpp b/clang/Analysis/GRExprEngine.cpp
index d2200bfa0fef..758e038865fd 100644
--- a/clang/Analysis/GRExprEngine.cpp
+++ b/clang/Analysis/GRExprEngine.cpp
@@ -26,6 +26,30 @@ using llvm::dyn_cast;
 using llvm::cast;
 using llvm::APSInt;
 
+GRExprEngine::StateTy GRExprEngine::getInitialState() {
+
+  // The LiveVariables information already has a compilation of all VarDecls
+  // used in the function.  Iterate through this set, and "symbolicate"
+  // any VarDecl whose value originally comes from outside the function.
+  
+  typedef LiveVariables::AnalysisDataTy LVDataTy;
+  LVDataTy& D = Liveness.getAnalysisData();
+  
+  ValueStateImpl StateImpl = *StateMgr.getInitialState().getImpl();
+  
+  for (LVDataTy::decl_iterator I=D.begin_decl(), E=D.end_decl(); I != E; ++I) {
+    
+    VarDecl* VD = cast<VarDecl>(const_cast<ScopedDecl*>(I->first));
+    
+    if (VD->hasGlobalStorage() || isa<ParmVarDecl>(VD)) {
+      RVal X = RVal::GetSymbolValue(SymMgr, VD);
+      StateMgr.BindVar(StateImpl, VD, X);
+    }
+  }
+  
+  return StateMgr.getPersistentState(StateImpl);
+}      
+      
 GRExprEngine::StateTy
 GRExprEngine::SetRVal(StateTy St, Expr* Ex, const RVal& V) {
 
@@ -455,22 +479,6 @@ void GRExprEngine::Nodify(NodeSet& Dst, Stmt* S, NodeTy* Pred,
 
 void GRExprEngine::VisitDeclRefExpr(DeclRefExpr* D, NodeTy* Pred, NodeSet& Dst){
 
-  if (VarDecl* VD = dyn_cast<VarDecl>(D->getDecl()))
-    if (VD->hasGlobalStorage() || isa<ParmVarDecl>(VD)) {
-
-      StateTy StOld = Pred->getState();
-      StateTy St = Symbolicate(StOld, VD);
-
-      if (!(St == StOld)) {
-        if (D != CurrentStmt)
-          Nodify(Dst, D, Pred, St);
-        else
-          Nodify(Dst, D, Pred, SetRVal(St, D, GetRVal(St, D)));
-        
-        return;
-      }
-    }
-  
   if (D != CurrentStmt) {
     Dst.Add(Pred); // No-op. Simply propagate the current state unchanged.
     return;
@@ -884,20 +892,7 @@ void GRExprEngine::VisitLVal(Expr* Ex, NodeTy* Pred, NodeSet& Dst) {
   
   Ex = Ex->IgnoreParens();
   
-  if (DeclRefExpr* DR = dyn_cast<DeclRefExpr>(Ex)) {
-    
-    if (VarDecl* VD = dyn_cast<VarDecl>(DR->getDecl()))
-      if (VD->hasGlobalStorage() || isa<ParmVarDecl>(VD)) {
-        
-        StateTy StOld = Pred->getState();
-        StateTy St = Symbolicate(StOld, VD);
-        
-        if (!(St == StOld)) {
-          Nodify(Dst, Ex, Pred, St);
-          return;
-        }
-      }
-    
+  if (isa<DeclRefExpr>(Ex)) {
     Dst.Add(Pred);
     return;
   }
diff --git a/clang/Analysis/ValueState.cpp b/clang/Analysis/ValueState.cpp
index cdd616fb147a..b90e265af246 100644
--- a/clang/Analysis/ValueState.cpp
+++ b/clang/Analysis/ValueState.cpp
@@ -437,10 +437,14 @@ ValueState ValueStateManager::SetRVal(ValueState St, LVal LV, RVal V) {
   }
 }
 
+void ValueStateManager::BindVar(ValueStateImpl& StImpl, VarDecl* D, RVal V) {
+  StImpl.VarBindings = VBFactory.Add(StImpl.VarBindings, D, V);
+}
+
 ValueState ValueStateManager::BindVar(ValueState St, VarDecl* D, RVal V) {
   
   // Create a new state with the old binding removed.
-  ValueStateImpl NewSt = *St;
+  ValueStateImpl NewSt = *St;  
   NewSt.VarBindings = VBFactory.Add(NewSt.VarBindings, D, V);
   
   // Get the persistent copy.
diff --git a/clang/include/clang/Analysis/PathSensitive/GRExprEngine.h b/clang/include/clang/Analysis/PathSensitive/GRExprEngine.h
index 16fd97710500..13abf53cb39f 100644
--- a/clang/include/clang/Analysis/PathSensitive/GRExprEngine.h
+++ b/clang/include/clang/Analysis/PathSensitive/GRExprEngine.h
@@ -150,7 +150,7 @@ public:
   
   /// getInitialState - Return the initial state used for the root vertex
   ///  in the ExplodedGraph.
-  StateTy getInitialState() { return StateMgr.getInitialState(); }
+  StateTy getInitialState();
   
   bool isUninitControlFlow(const NodeTy* N) const {
     return N->isSink() && UninitBranches.count(const_cast<NodeTy*>(N)) != 0;
@@ -252,15 +252,6 @@ protected:
     return StateMgr.GetLVal(St, Ex);
   }
   
-  StateTy Symbolicate(StateTy St, VarDecl* VD) {
-    lval::DeclVal X(VD);
-    
-    if (GetRVal(St, X).isUnknown()) {
-      return SetRVal(St, lval::DeclVal(VD), RVal::GetSymbolValue(SymMgr, VD));
-    }
-    else return St;
-  }
-  
   inline NonLVal MakeConstantVal(uint64_t X, Expr* Ex) {
     return NonLVal::MakeVal(ValMgr, X, Ex->getType(), Ex->getLocStart());
   }
diff --git a/clang/include/clang/Analysis/PathSensitive/ValueState.h b/clang/include/clang/Analysis/PathSensitive/ValueState.h
index 5458ab86e59c..c3e913ab703f 100644
--- a/clang/include/clang/Analysis/PathSensitive/ValueState.h
+++ b/clang/include/clang/Analysis/PathSensitive/ValueState.h
@@ -266,6 +266,7 @@ public:
   
   RVal GetBlkExprRVal(ValueState St, Expr* Ex);
   
+  void BindVar(ValueStateImpl& StImpl, VarDecl* D, RVal V);
   ValueState getPersistentState(const ValueStateImpl& Impl);
   
   ValueState AddEQ(ValueState St, SymbolID sym, const llvm::APSInt& V);