[PGO] Comment how function pointers for indirect calls are mapped to function names

Summary:
Hopefully this will make it easier for the next person to figure all
this out...

Reviewers: bogner, davidxl

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D18490

llvm-svn: 264611
diff --git a/llvm/lib/ProfileData/InstrProfReader.cpp b/llvm/lib/ProfileData/InstrProfReader.cpp
index b00c139..27142e0 100644
--- a/llvm/lib/ProfileData/InstrProfReader.cpp
+++ b/llvm/lib/ProfileData/InstrProfReader.cpp
@@ -412,6 +412,9 @@
   if (VDataPtrOrErr.getError())
     return VDataPtrOrErr.getError();
 
+  // Note that besides deserialization, this also performs the conversion for
+  // indirect call targets.  The function pointers from the raw profile are
+  // remapped into function name hashes.
   VDataPtrOrErr.get()->deserializeTo(Record, &Symtab->getAddrHashMap());
   CurValueDataSize = VDataPtrOrErr.get()->getSize();
   return success();