Re: [LTO][PATCH] Compress LTO IL sections in object files

["Joseph S. Myers" <joseph at codesourcery dot com>]

On Fri, 8 May 2009, Simon Baldwin wrote:

> 	* Makefile.in: Added entries to build lto-compress module, added
> 	ZLIB to cc1 link lines.

To add a new required host library you generally need to:

* Add configure options specifying where to find any pre-installed copy 
that may not be in the default headers and libraries search path, along 
the lines of those for GMP. MPFR, CLooG, PPL.

* Document the library as required in install.texi.

* Document the configure options in install.texi.

In the case of zlib, GCC has an imported copy for use of libjava so you 
might be able to make sure the imported copy is built as a static library 
for the host and used by default (unless --with-system-zlib is passed) as 
an alternative to these items - it's not clear there's any need for 
options to specify where to find a pre-built zlib copy different from the 
system one when GCC builds its own.  You should also make sure that 
--with-system-zlib uses the system copy.  If you have verified these 
conditions already hold then say so.

> +#include "zlib.h"
> +#include "config.h"
> +#include "system.h"

zlib.h is a system header.  It includes other system headers.  Those 
headers may test feature test macros.  config.h may define feature test 
macros.  You cannot include zlib.h before config.h safely.  Include it 
*after* including config.h and system.h, and use <zlib.h> not "zlib.h" 
since it is a system header.

> Index: gcc/lto-compress.h
> ===================================================================
> --- gcc/lto-compress.h	(revision 0)
> +++ gcc/lto-compress.h	(revision 0)
> @@ -0,0 +1,37 @@
> +/* LTO IL compression streams.
> +
> +   Copyright 2009 Free Software Foundation, Inc.
> +   Contributed by Simon Baldwin <simonb@google.com>
> +
> +This file is part of GCC.
> +
> +GCC is free software; you can redistribute it and/or modify
> +it under the terms of the GNU General Public License as published by
> +the Free Software Foundation; either version 2, or (at your option)
> +any later version.

No new files should have GPLv2 notices.  Use the standard form of GPLv3 
notice in GCC, and make sure that all other files present on LTO branch 
but not on trunk do so.

-- 
Joseph S. Myers
joseph@codesourcery.com