[analyzer] Refactor RegionStore's sub-region bindings traversal.

This is going to be used in the next commit.
While I'm here, tighten up assumptions about symbolic offset
BindingKeys, and make offset calculation explicitly handle all
MemRegion kinds.

No functionality change.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@175228 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 23 insertions, 2 deletions

diff --git a/lib/StaticAnalyzer/Core/MemRegion.cpp b/lib/StaticAnalyzer/Core/MemRegion.cpp
index 687c7c0188..a0abe42253 100644
--- a/lib/StaticAnalyzer/Core/MemRegion.cpp
+++ b/lib/StaticAnalyzer/Core/MemRegion.cpp
@@ -1080,16 +1080,37 @@ RegionOffset MemRegion::getAsOffset() const {
 
   while (1) {
     switch (R->getKind()) {
-    default:
-      return RegionOffset(R, RegionOffset::Symbolic);
+    case GenericMemSpaceRegionKind:
+    case StackLocalsSpaceRegionKind:
+    case StackArgumentsSpaceRegionKind:
+    case HeapSpaceRegionKind:
+    case UnknownSpaceRegionKind:
+    case StaticGlobalSpaceRegionKind:
+    case GlobalInternalSpaceRegionKind:
+    case GlobalSystemSpaceRegionKind:
+    case GlobalImmutableSpaceRegionKind:
+      // Stores can bind directly to a region space to set a default value.
+      assert(Offset == 0 && !SymbolicOffsetBase);
+      goto Finish;
+
+    case FunctionTextRegionKind:
+    case BlockTextRegionKind:
+    case BlockDataRegionKind:
+      // These will never have bindings, but may end up having values requested
+      // if the user does some strange casting.
+      if (Offset != 0)
+        SymbolicOffsetBase = R;
+      goto Finish;
 
     case SymbolicRegionKind:
     case AllocaRegionKind:
     case CompoundLiteralRegionKind:
     case CXXThisRegionKind:
     case StringRegionKind:
+    case ObjCStringRegionKind:
     case VarRegionKind:
     case CXXTempObjectRegionKind:
+      // Usual base regions.
       goto Finish;
 
     case ObjCIvarRegionKind: