Fix comments of createReplaceableForwardDecl() and createForwardDecl().

Noticed while trying to understand how the merge of forward decalred types
and defintions work.

Reviewers: echristo, dblaikie, aprantl

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D5291

llvm-svn: 217514
diff --git a/llvm/lib/IR/DIBuilder.cpp b/llvm/lib/IR/DIBuilder.cpp
index c3beae9..181c60f 100644
--- a/llvm/lib/IR/DIBuilder.cpp
+++ b/llvm/lib/IR/DIBuilder.cpp
@@ -879,8 +879,7 @@
   return DIBasicType();
 }
 
-/// createForwardDecl - Create a temporary forward-declared type that
-/// can be RAUW'd if the full type is seen.
+/// createForwardDecl - Create a permanent forward-declared type.
 DICompositeType
 DIBuilder::createForwardDecl(unsigned Tag, StringRef Name, DIDescriptor Scope,
                              DIFile F, unsigned Line, unsigned RuntimeLang,
@@ -914,7 +913,7 @@
   return RetTy;
 }
 
-/// createForwardDecl - Create a temporary forward-declared type that
+/// createReplaceableForwardDecl - Create a temporary forward-declared type that
 /// can be RAUW'd if the full type is seen.
 DICompositeType DIBuilder::createReplaceableForwardDecl(
     unsigned Tag, StringRef Name, DIDescriptor Scope, DIFile F, unsigned Line,
@@ -942,7 +941,7 @@
   MDNode *Node = MDNode::getTemporary(VMContext, Elts);
   DICompositeType RetTy(Node);
   assert(RetTy.isCompositeType() &&
-         "createForwardDecl result should be a DIType");
+         "createReplaceableForwardDecl result should be a DIType");
   if (!UniqueIdentifier.empty())
     retainType(RetTy);
   return RetTy;