IR: Remove implicit iterator conversions from lib/IR, NFC

Stop converting implicitly between iterators and pointers/references in
lib/IR.  For convenience, I've added a `getIterator()` accessor to
`ilist_node` so that callers don't need to know how to spell the
iterator class (i.e., they can use `X.getIterator()` instead of
`Function::iterator(X)`).

I'll eventually disallow these implicit conversions entirely, but
there's a lot of code, so it doesn't make sense to do it all in one
patch.  One library or so at a time.

Why?  To root out cases of `getNextNode()` and `getPrevNode()` being
used in iterator logic.  The design of `ilist` makes that invalid when
the current node could be at the back of the list, but it happens to
"work" right now because of a bug where those functions never return
`nullptr` if you're using a half-node sentinel.  Before I can fix the
function, I have to remove uses of it that rely on it misbehaving.
(Maybe the function should just be deleted anyway?  But I don't want
deleting it -- potentially a huge project -- to block fixing
ilist/iplist.)

llvm-svn: 249782

1 files changed, 1 insertions, 1 deletions

diff --git a/llvm/lib/IR/SymbolTableListTraitsImpl.h b/llvm/lib/IR/SymbolTableListTraitsImpl.h
index e7fa8ba58f4..50573d8d688 100644
--- a/llvm/lib/IR/SymbolTableListTraitsImpl.h
+++ b/llvm/lib/IR/SymbolTableListTraitsImpl.h
@@ -55,7 +55,7 @@ void SymbolTableListTraits<ValueSubClass>::setSymTabObject(TPtr *Dest,
     // Add all of the items to the new symtab.
     for (auto I = ItemList.begin(); I != ItemList.end(); ++I)
       if (I->hasName())
-        NewST->reinsertValue(I);
+        NewST->reinsertValue(&*I);
   }
   
 }