Relax RegionStore to allow loads from CodeTextRegions. Apparently you…

… can actually write code that does this. This seems worthy of a checker, but the StoreManager should handle the memory abstraction without crashing. Fixes PR 11450.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@145424 91177308-0d34-0410-b5e6-96231b3b80d8

lib/StaticAnalyzer/Core/RegionStore.cpp

@@ -882,18 +882,16 @@ SVal RegionStoreManager::Retrieve(Store store, Loc L, QualType T) {
 
   const MemRegion *MR = cast<loc::MemRegionVal>(L).getRegion();
 
-  if (isa<AllocaRegion>(MR) || isa<SymbolicRegion>(MR)) {
+  if (isa<AllocaRegion>(MR) ||
+      isa<SymbolicRegion>(MR) ||
+      isa<CodeTextRegion>(MR)) {
     if (T.isNull()) {
       const SymbolicRegion *SR = cast<SymbolicRegion>(MR);
       T = SR->getSymbol()->getType(Ctx);
     }
     MR = GetElementZeroRegion(MR, T);
   }
 
-  if (isa<CodeTextRegion>(MR)) {
-    llvm_unreachable("Why load from a code text region?");
-  }
-
   // FIXME: Perhaps this method should just take a 'const MemRegion*' argument
   //  instead of 'Loc', and have the other Loc cases handled at a higher level.
   const TypedValueRegion *R = cast<TypedValueRegion>(MR);

test/Analysis/misc-ps-region-store.cpp

@@ -484,3 +484,11 @@ void PR11249()
     *p = 0xDEADBEEF;  // no-warning
 }
 
+// Handle doing a load from the memory associated with the code for
+// a function.
+extern double nan( const char * );
+double PR11450() {
+  double NaN = *(double*) nan;
+  return NaN;
+}
+