Implemented deserialization of references. References are handled

just like pointers, except that they cannot be backpatched.  This
means that references are essentially non-owning pointers where the
referred object must be deserialized prior to the reference being
deserialized.  Because of the nature of references, this ordering of
objects is always possible.

Fixed a bug in backpatching code (returning the backpatched pointer
would accidentally include a bit flag).

llvm-svn: 43570

1 files changed, 13 insertions, 1 deletions

diff --git a/llvm/lib/Bitcode/Reader/Deserialize.cpp b/llvm/lib/Bitcode/Reader/Deserialize.cpp
index ff0dd44dc25..4b58cf41dc1 100644
--- a/llvm/lib/Bitcode/Reader/Deserialize.cpp
+++ b/llvm/lib/Bitcode/Reader/Deserialize.cpp
@@ -115,7 +115,7 @@ void Deserializer::ReadUIntPtr(uintptr_t& PtrRef) {
   BPatchEntry& E = BPatchMap[PtrId];
   
   if (E.hasFinalPtr())
-    PtrRef = E.getRawPtr();
+    PtrRef = E.getFinalPtr();
   else {
     // Register backpatch.  Check the freelist for a BPNode.
     BPNode* N;
@@ -132,6 +132,18 @@ void Deserializer::ReadUIntPtr(uintptr_t& PtrRef) {
   }
 }
 
+uintptr_t Deserializer::ReadInternalRefPtr() {
+  unsigned PtrId = ReadInt();
+  
+  assert (PtrId != 0 && "References cannot refer the NULL address.");
+
+  BPatchEntry& E = BPatchMap[PtrId];
+  
+  assert (E.hasFinalPtr() &&
+          "Cannot backpatch references.  Object must be already deserialized.");
+  
+  return E.getFinalPtr();
+}
 
 void Deserializer::BPatchEntry::setFinalPtr(BPNode*& FreeList, void* P) {
   assert (!hasFinalPtr());