IR: Remove MDNodeFwdDecl

Remove `MDNodeFwdDecl` (as promised in r226481).  Aside from API
changes, there's no real functionality change here.
`MDNode::getTemporary()` now forwards to `MDTuple::getTemporary()`,
which returns a tuple with `isTemporary()` equal to true.

The main point is that we can now add temporaries of other `MDNode`
subclasses, needed for PR22235 (I introduced `MDNodeFwdDecl` in the
first place because I didn't recognize this need, and thought they were
only needed to handle forward references).

A few things left out of (or highlighted by) this commit:

  - I've had to remove the (few) uses of `std::unique_ptr<>` to deal
    with temporaries, since the destructor is no longer public.
    `getTemporary()` should probably return the equivalent of
    `std::unique_ptr<T, MDNode::deleteTemporary>`.
  - `MDLocation::getTemporary()` doesn't exist yet (worse, it actually
    does exist, but does the wrong thing: `MDNode::getTemporary()` is
    inherited and returns an `MDTuple`).
  - `MDNode` now only has one subclass, `UniquableMDNode`, and the
    distinction between them is actually somewhat confusing.

I'll fix those up next.

llvm-svn: 226501

1 files changed, 3 insertions, 3 deletions

diff --git a/llvm/lib/AsmParser/LLParser.cpp b/llvm/lib/AsmParser/LLParser.cpp
index 11a5983c8ad..ce195381cfb 100644
--- a/llvm/lib/AsmParser/LLParser.cpp
+++ b/llvm/lib/AsmParser/LLParser.cpp
@@ -531,7 +531,7 @@ bool LLParser::ParseMDNodeID(MDNode *&Result) {
   }
 
   // Otherwise, create MDNode forward reference.
-  MDNodeFwdDecl *FwdNode = MDNodeFwdDecl::get(Context, None);
+  MDTuple *FwdNode = MDTuple::getTemporary(Context, None);
   ForwardRefMDNodes[MID] = std::make_pair(FwdNode, Lex.getLoc());
 
   if (NumberedMetadata.size() <= MID)
@@ -597,9 +597,9 @@ bool LLParser::ParseStandaloneMetadata() {
   // See if this was forward referenced, if so, handle it.
   auto FI = ForwardRefMDNodes.find(MetadataID);
   if (FI != ForwardRefMDNodes.end()) {
-    MDNodeFwdDecl *Temp = FI->second.first;
+    MDTuple *Temp = FI->second.first;
     Temp->replaceAllUsesWith(Init);
-    delete Temp;
+    MDNode::deleteTemporary(Temp);
     ForwardRefMDNodes.erase(FI);
 
     assert(NumberedMetadata[MetadataID] == Init && "Tracking VH didn't work");