[1/3] Drop traversable_base::traverse method.

  The traverse method is defined in the traversable_base class but is
never used as the synonymous methods in the derived classes have
different argument types and so hide it.

The function can be removed and consequently the source file
abg-traverse.cc too.

This removes a trigger of Clang's -Werror-overloaded-virtual which is
enabled with -Wmost which is enabled by -Wall.

	* include/abg-traverse.h (class traversable_base): Add
	class-level comment about expected usage, drop declaration of
	traverse method.
	* src/Makefile.am: Remove mention of src/abg-traverse.cc.
	* src/abg-traverse.cc: Remove file as it only contains the
	unused traversable_base::traverse method.

Signed-off-by: Giuliano Procida <gprocida@google.com>
---
 include/abg-traverse.h | 21 ++++++---------------
 src/Makefile.am        |  1 -
 src/abg-traverse.cc    | 43 ------------------------------------------
 3 files changed, 6 insertions(+), 59 deletions(-)
 delete mode 100644 src/abg-traverse.cc
  

On Thu, Jul 09, 2020 at 07:22:48PM +0100, Giuliano Procida wrote:
>The traverse method is defined in the traversable_base class but is
>never used as the synonymous methods in the derived classes have
>different argument types and so hide it.
>
>The function can be removed and consequently the source file
>abg-traverse.cc too.
>
>This removes a trigger of Clang's -Werror-overloaded-virtual which is
>enabled with -Wmost which is enabled by -Wall.
>
>	* include/abg-traverse.h (class traversable_base): Add
>	class-level comment about expected usage, drop declaration of
>	traverse method.
>	* src/Makefile.am: Remove mention of src/abg-traverse.cc.
>	* src/abg-traverse.cc: Remove file as it only contains the
>	unused traversable_base::traverse method.
>
>Signed-off-by: Giuliano Procida <gprocida@google.com>

Reviewed-by: Matthias Maennich <maennich@google.com>

Cheers,
Matthias

>---
> include/abg-traverse.h | 21 ++++++---------------
> src/Makefile.am        |  1 -
> src/abg-traverse.cc    | 43 ------------------------------------------
> 3 files changed, 6 insertions(+), 59 deletions(-)
> delete mode 100644 src/abg-traverse.cc
>
>diff --git a/include/abg-traverse.h b/include/abg-traverse.h
>index a7170dad..2cb84804 100644
>--- a/include/abg-traverse.h
>+++ b/include/abg-traverse.h
>@@ -44,6 +44,12 @@ struct node_visitor_base
>
> /// The interface for types which are feeling social and want to be
> /// visited during the traversal of a hierarchy of nodes.
>+///
>+/// It is expected that classes derived from traversable_base define a
>+/// traverse method specialised to the node *visitor* type. Such
>+/// methods should visit nodes recursively, calling
>+/// ir_node_visitor::visit for each node. The method should return
>+/// true until all nodes have been visited.
> class traversable_base
> {
>   bool visiting_;
>@@ -78,21 +84,6 @@ public:
>   {}
>
>   virtual ~traversable_base() {}
>-
>-  /// This virtual method is overloaded and implemented by any single
>-  /// type which instance is going to be visited during the traversal
>-  /// of translation unit nodes.
>-  ///
>-  /// The method visits a given node and, for scopes, visits their
>-  /// member nodes.  Visiting a node means calling the
>-  /// ir_node_visitor::visit method with the node passed as an
>-  /// argument.
>-  ///
>-  /// @param v the visitor used during the traverse.
>-  ///
>-  /// @return true if traversed until the end of the type tree, false
>-  /// otherwise.
>-  virtual bool traverse(node_visitor_base& v);
> };
>
> }// end namespace ir.
>diff --git a/src/Makefile.am b/src/Makefile.am
>index 1153a5f8..7684e373 100644
>--- a/src/Makefile.am
>+++ b/src/Makefile.am
>@@ -13,7 +13,6 @@ endif
>
> libabigail_la_SOURCES =			\
> abg-internal.h				\
>-abg-traverse.cc				\
> abg-ir-priv.h				\
> abg-ir.cc				\
> abg-corpus-priv.h			\
>diff --git a/src/abg-traverse.cc b/src/abg-traverse.cc
>deleted file mode 100644
>index 3fb87ea2..00000000
>--- a/src/abg-traverse.cc
>+++ /dev/null
>@@ -1,43 +0,0 @@
>-// -*- Mode: C++ -*-
>-//
>-// Copyright (C) 2013-2020 Red Hat, Inc.
>-//
>-// This file is part of the GNU Application Binary Interface Generic
>-// Analysis and Instrumentation Library (libabigail).  This library is
>-// free software; you can redistribute it and/or modify it under the
>-// terms of the GNU Lesser General Public License as published by the
>-// Free Software Foundation; either version 3, or (at your option) any
>-// later version.
>-
>-// This library is distributed in the hope that it will be useful, but
>-// WITHOUT ANY WARRANTY; without even the implied warranty of
>-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
>-// General Lesser Public License for more details.
>-
>-// You should have received a copy of the GNU Lesser General Public
>-// License along with this program; see the file COPYING-LGPLV3.  If
>-// not, see <http://www.gnu.org/licenses/>.
>-
>-/// @file
>-
>-#include "abg-internal.h"
>-// <headers defining libabigail's API go under here>
>-ABG_BEGIN_EXPORT_DECLARATIONS
>-
>-#include "abg-traverse.h"
>-
>-ABG_END_EXPORT_DECLARATIONS
>-// </headers defining libabigail's API>
>-
>-namespace abigail
>-{
>-
>-namespace ir
>-{
>-
>-bool
>-traversable_base::traverse(node_visitor_base&)
>-{return true;}
>-
>-}// end namaspace ir
>-}// end namespace abigail
>-- 
>2.27.0.383.g050319c2ae-goog
>
  

Giuliano Procida <gprocida@google.com> a écrit:

> The traverse method is defined in the traversable_base class but is
> never used as the synonymous methods in the derived classes have
> different argument types and so hide it.

The derived classes have a traverse method which parameter type
(ir_node_visitor and diff_node_visitor) derives from the type of the
parameter of traversable_base::traverse (node_visitor_base).  And that
is by design.  So yes they are different, but they are closely
related.

So I'd like to keep the traversable_base::traverse method at least as a
comment, saying that types that extend traversable_base ought to declare
a virtual traverse method which type extends node_visitor_base.

I've done so in the attached patch I am applying.

> The function can be removed and consequently the source file
> abg-traverse.cc too.

Rather than removing abg-traverse.cc, I'd pimpl-ify abg-traverse.h and
move its inline definitions into abg-traverse.cc.  This gets
abg-traverse.h closer to a somewhat achieving some a{b,p}i stability in
the future.  It's a generic "backburner" goal that I have and I think
removing this file gets me further from it.

So I've done that in the patch as well.

[...]

Please find attached the patch I am applying to master.

Cheers,