From 2f6eb14af4c4de9b334320f9d25203c675133cef Mon Sep 17 00:00:00 2001
From: Ted Kremenek <kremenek@apple.com>
Date: Thu, 6 Aug 2009 21:43:54 +0000
Subject: Fix a couple false positive "uninitialized value" warnings with
 RegionStore involving reasoning about unions (which we don't handle yet).

llvm-svn: 78342
---
 clang/lib/Analysis/RegionStore.cpp | 23 ++++++++++++++++++++++-
 1 file changed, 22 insertions(+), 1 deletion(-)

(limited to 'clang/lib/Analysis/RegionStore.cpp')

diff --git a/clang/lib/Analysis/RegionStore.cpp b/clang/lib/Analysis/RegionStore.cpp
index 32167560451..8cb4d980214 100644
--- a/clang/lib/Analysis/RegionStore.cpp
+++ b/clang/lib/Analysis/RegionStore.cpp
@@ -18,6 +18,7 @@
 #include "clang/Analysis/PathSensitive/GRState.h"
 #include "clang/Analysis/PathSensitive/GRStateTrait.h"
 #include "clang/Analysis/Analyses/LiveVariables.h"
+#include "clang/Analysis/Support/Optional.h"
 #include "clang/Basic/TargetInfo.h"
 
 #include "llvm/ADT/ImmutableMap.h"
@@ -187,6 +188,11 @@ public:
     
   RegionStoreSubRegionMap *getRegionStoreSubRegionMap(const GRState *state);
   
+  
+  /// getDefaultBinding - Returns an SVal* representing an optional default
+  ///  binding associated with a region and its subregions.
+  Optional<SVal> getDefaultBinding(const GRState *state, const MemRegion *R);
+  
   /// getLValueString - Returns an SVal representing the lvalue of a
   ///  StringLiteral.  Within RegionStore a StringLiteral has an
   ///  associated StringRegion, and the lvalue of a StringLiteral is
@@ -829,6 +835,17 @@ SVal RegionStoreManager::EvalBinOp(const GRState *state,
 // Loading values from regions.
 //===----------------------------------------------------------------------===//
 
+Optional<SVal> RegionStoreManager::getDefaultBinding(const GRState *state,
+                                                     const MemRegion *R) {
+  
+  if (R->isBoundable())
+    if (const TypedRegion *TR = dyn_cast<TypedRegion>(R))
+      if (TR->getValueType(getContext())->isUnionType())
+        return UnknownVal();
+
+  return Optional<SVal>::create(state->get<RegionDefaultValue>(R));
+}
+
 static bool IsReinterpreted(QualType RTy, QualType UsedTy, ASTContext &Ctx) {
   RTy = Ctx.getCanonicalType(RTy);
   UsedTy = Ctx.getCanonicalType(UsedTy);
@@ -911,6 +928,10 @@ RegionStoreManager::Retrieve(const GRState *state, Loc L, QualType T) {
 
   if (RTy->isStructureType())
     return SValuator::CastResult(state, RetrieveStruct(state, R));
+  
+  // FIXME: Handle unions.
+  if (RTy->isUnionType())
+    return SValuator::CastResult(state, UnknownVal());
 
   if (RTy->isArrayType())
     return SValuator::CastResult(state, RetrieveArray(state, R));
@@ -1109,7 +1130,7 @@ SVal RegionStoreManager::RetrieveField(const GRState* state,
 
   const MemRegion* superR = R->getSuperRegion();
   while (superR) {
-    if (const SVal* D = state->get<RegionDefaultValue>(superR)) {
+    if (const Optional<SVal> &D = getDefaultBinding(state, superR)) {
       if (SymbolRef parentSym = D->getAsSymbol())
         return ValMgr.getDerivedRegionValueSymbolVal(parentSym, R);
 
-- 
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