ADT: Explode include/llvm/ADT/{ilist,ilist_node}.h, NFC

I'm working on a lower-level intrusive list that can be used
stand-alone, and splitting the files up a bit will make the code easier
to organize.  Explode the ilist headers in advance to improve blame
lists in the future.
- Move ilist_node_base from ilist_node.h to ilist_node_base.h.
- Move ilist_base from ilist.h to ilist_base.h.
- Move ilist_iterator from ilist.h to ilist_iterator.h.
- Move ilist_node_access from ilist.h to ilist_node.h to support
  ilist_iterator.
- Update unit tests to #include smaller headers.
- Clang-format the moved things.

I noticed in transit that there is a simplify_type specialization for
ilist_iterator.  Since there is no longer an implicit conversion from
ilist<T>::iterator to T*, this doesn't make sense (effectively it's a
form of implicit conversion).  For now I've added a FIXME.

llvm-svn: 280047

1 files changed, 1 insertions, 1 deletions

diff --git a/llvm/unittests/ADT/IListNodeBaseTest.cpp b/llvm/unittests/ADT/IListNodeBaseTest.cpp
index 1e9c2a1fa04..0fb1282b21d 100644
--- a/llvm/unittests/ADT/IListNodeBaseTest.cpp
+++ b/llvm/unittests/ADT/IListNodeBaseTest.cpp
@@ -7,7 +7,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "llvm/ADT/ilist_node.h"
+#include "llvm/ADT/ilist_node_base.h"
 #include "gtest/gtest.h"
 
 using namespace llvm;