Implement function prefix data as an IR feature.

Previous discussion:
http://lists.cs.uiuc.edu/pipermail/llvmdev/2013-July/063909.html

Differential Revision: http://llvm-reviews.chandlerc.com/D1191

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190773 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Bitcode/Writer/ValueEnumerator.cpp b/lib/Bitcode/Writer/ValueEnumerator.cpp
index 8bac6da..a164104 100644
--- a/lib/Bitcode/Writer/ValueEnumerator.cpp
+++ b/lib/Bitcode/Writer/ValueEnumerator.cpp
@@ -60,6 +60,11 @@
        I != E; ++I)
     EnumerateValue(I->getAliasee());
 
+  // Enumerate the prefix data constants.
+  for (Module::const_iterator I = M->begin(), E = M->end(); I != E; ++I)
+    if (I->hasPrefixData())
+      EnumerateValue(I->getPrefixData());
+
   // Insert constants and metadata that are named at module level into the slot
   // pool so that the module symbol table can refer to them...
   EnumerateValueSymbolTable(M->getValueSymbolTable());