[PATCH (updated)] Convert symtab, cgraph and varpool nodes into a real class hierarchy

[David Malcolm <dmalcolm at redhat dot com>]

On Fri, 2013-09-20 at 17:33 +0200, Jan Hubicka wrote:
> > This patch is the handwritten part of the conversion of these types
> > to C++; it requires the followup patch, which is autogenerated.
> > 
> > It converts:
> >   struct symtab_node_base
> > to:
> >   class symtab_node_base
> > 
> > and converts:
> >   struct cgraph_node
> > to:
> >   struct cgraph_node : public symtab_node_base
> > and:
> >   struct varpool_node
> > to:
> >   class varpool_node : public symtab_node_base
> > 
> > dropping the symtab_node_def union.
> 
> Yep, incrementally we should continue with the grand renaming 
> retiring symtab_node_base and getting things symmetric.
> > 
> > 	* cgraph.h (symtab_node_base): Convert to a class;
> > 	add GTY((desc ("%h.type"), tag ("SYMTAB_SYMBOL"))).
> > 	(cgraph_node): Inherit from symtab_node; add GTY option
> > 	tag ("SYMTAB_FUNCTION").
> > 	(varpool_node): Inherit from symtab_node; add GTY option
> > 	tag ("SYMTAB_VARIABLE").
> > 	(symtab_node_def): Remove.
> > 	(is_a_helper <cgraph_node>::test (symtab_node_def *)): Convert to...
> > 	(is_a_helper <cgraph_node>::test (symtab_node_base *)): ...this.
> > 	(is_a_helper <varpool_node>::test (symtab_node_def *)): Convert to...
> > 	(is_a_helper <varpool_node>::test (symtab_node_base *)): ...this.
> > 
> > 	* ipa-ref.h (symtab_node_def): Drop.
> > 	(symtab_node): Change underlying type from symtab_node_def to
> > 	symtab_node_base.
> > 	(const_symtab_node): Likwise.
> > 
> > 	* is-a.h: Update examples in comment.
> > 
> > 	* symtab.c (symtab_hash): Change symtab_node_def to symtab_node_base.
> > 	(assembler_name_hash): Likewise.
> 
> This patch is OK.  Thanks for working on this!

These symtab changes were dependent on having gengtype support for
inheritance, which is now in trunk, so I'm now revisiting these patches.

The above patch hasn't bitrotted, though the autogenerated one that goes
with it needed regenerating.

A new version of the autogenerated patch can be seen at:
http://dmalcolm.fedorapeople.org/gcc/large-patches/eaba9669644c84592ea32be2dcd19ba92beca381-0003-Autogenerated-fixes-of-symbol.-to.patch
Is that new patch OK?  (it's 450KB so one's eyes tend to glaze over
after a while, but FWIW you approved an earlier version of that in:
  http://gcc.gnu.org/ml/gcc-patches/2013-09/msg00730.html
and the test suite for the script that generated the patch can be seen
at:
https://github.com/davidmalcolm/gcc-refactoring-scripts/blob/master/test_refactor_symtab.py )

Also, I noticed when reviewing the autogenerated marking routines in
gtype-desc.c that the symtab_node_def union had chain_next/chain_prev
markings, and that my patch above effectively dropped them.

The attached patch reinstates them, albeit to the symtab_node_base base
class, and inspection of the generated gtype-desc.c shows that the
generated code does the right thing.

Is this change also OK for trunk?

(I'm still bootstrapping/regtesting the patch series now, so the above
is all conditional on that, so my apologies if this turns out to be
premature).

Dave

>From f070f1ecc2baa536d121f2942bd8af750dbc2f02 Mon Sep 17 00:00:00 2001
From: David Malcolm <dmalcolm@redhat.com>
Date: Mon, 28 Oct 2013 22:25:38 -0400
Subject: [PATCH 2/3] Add chain_next and chain_prev options back to
 symtab_node_base

gcc/
	* cgraph.h (symtab_node_base): Add missing chain_next and
	chain_prev GTY options.
---
 gcc/cgraph.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/gcc/cgraph.h b/gcc/cgraph.h
index 5a582d8..35f79ec 100644
--- a/gcc/cgraph.h
+++ b/gcc/cgraph.h
@@ -39,7 +39,7 @@ enum symtab_type
 
 /* Base of all entries in the symbol table.
    The symtab_node is inherited by cgraph and varpol nodes.  */
-class GTY((desc ("%h.type"), tag ("SYMTAB_SYMBOL"))) symtab_node_base
+class GTY((desc ("%h.type"), tag ("SYMTAB_SYMBOL"), chain_next ("%h.next"), chain_prev ("%h.previous"))) symtab_node_base
 {
 public:
   /* Type of the symbol.  */
-- 
1.7.11.7