[PATCH, bootstrap]: Add bootstrap-lto-noplugin build configuration (PR65537)

[PATCH, bootstrap]: Add bootstrap-lto-noplugin build configuration (PR65537)

[Uros Bizjak]

[-- Attachment #1: Type: text/plain, Size: 848 bytes --]

Hello!

Attached patch introduces bootstrap-lto-noplugin bootstrap
configuration for hosts that do not support linker plugin (e.g. CentOS
5.11 with binutils 2.17). Also, the patch adds some additional
documentation to bootstrap-lto option.

config/ChangeLog:

2015-03-24  Uros Bizjak  <ubizjak@gmail.com>

    PR bootstrap/65537
    * bootstrap-lto-noplugin.mk: New build configuration.

gcc/ChangeLog:

2015-03-24  Uros Bizjak  <ubizjak@gmail.com>

    PR bootstrap/65537
    * doc/install.texi (Building a native compiler): Document new
    bootstrap-lto-noplugin configuration.  Mention that bootstrap-lto
    configuration assumes that the host supports the linker plugin.

Patch was bootstrapped and tested on x86_64-linux-gnu (CentOS 5.11)
host, configured with --with-build-config=bootstrap-lto build
configuration.

OK for mainline?

Uros.

[-- Attachment #2: p.diff.txt --]
[-- Type: text/plain, Size: 1384 bytes --]

Index: config/bootstrap-lto-noplugin.mk
===================================================================
--- config/bootstrap-lto-noplugin.mk	(revision 0)
+++ config/bootstrap-lto-noplugin.mk	(working copy)
@@ -0,0 +1,6 @@
+# This option enables LTO for stage2 and stage3 on
+# hosts without linker plugin support.
+
+STAGE2_CFLAGS += -flto=jobserver -frandom-seed=1 -ffat-lto-objects
+STAGE3_CFLAGS += -flto=jobserver -frandom-seed=1 -ffat-lto-objects
+STAGEprofile_CFLAGS += -fno-lto
Index: gcc/doc/install.texi
===================================================================
--- gcc/doc/install.texi	(revision 221636)
+++ gcc/doc/install.texi	(working copy)
@@ -2519,8 +2519,14 @@
 @item @samp{bootstrap-lto}
 Enables Link-Time Optimization for host tools during bootstrapping.
 @samp{BUILD_CONFIG=bootstrap-lto} is equivalent to adding
-@option{-flto} to @samp{BOOT_CFLAGS}.
+@option{-flto} to @samp{BOOT_CFLAGS}.  This option assumes that the host
+supports the linker plugin (e.g. GNU ld version 2.21 or later or GNU gold
+version 2.21 or later).
 
+@item @samp{bootstrap-lto-noplugin}
+This option is similar to @code{bootstrap-lto}, but is intended for
+hosts that do not support the linker plugin.
+
 @item @samp{bootstrap-debug}
 Verifies that the compiler generates the same executable code, whether
 or not it is asked to emit debug information.  To this end, this

Re: [PATCH, bootstrap]: Add bootstrap-lto-noplugin build configuration (PR65537)

[Jakub Jelinek]

On Tue, Mar 24, 2015 at 05:43:09PM +0100, Uros Bizjak wrote:
> Attached patch introduces bootstrap-lto-noplugin bootstrap
> configuration for hosts that do not support linker plugin (e.g. CentOS
> 5.11 with binutils 2.17). Also, the patch adds some additional
> documentation to bootstrap-lto option.
> 
> config/ChangeLog:
> 
> 2015-03-24  Uros Bizjak  <ubizjak@gmail.com>
> 
>     PR bootstrap/65537
>     * bootstrap-lto-noplugin.mk: New build configuration.
> 
> gcc/ChangeLog:
> 
> 2015-03-24  Uros Bizjak  <ubizjak@gmail.com>
> 
>     PR bootstrap/65537
>     * doc/install.texi (Building a native compiler): Document new
>     bootstrap-lto-noplugin configuration.  Mention that bootstrap-lto
>     configuration assumes that the host supports the linker plugin.
> 
> Patch was bootstrapped and tested on x86_64-linux-gnu (CentOS 5.11)
> host, configured with --with-build-config=bootstrap-lto build
> configuration.

and not --with-build-config=bootstrap-lto-noplugin ?

> OK for mainline?

Ok, thanks.

	Jakub

Re: [PATCH, bootstrap]: Add bootstrap-lto-noplugin build configuration (PR65537)

[Uros Bizjak]

On Wed, Mar 25, 2015 at 3:23 PM, Jakub Jelinek <jakub@redhat.com> wrote:

>> Attached patch introduces bootstrap-lto-noplugin bootstrap
>> configuration for hosts that do not support linker plugin (e.g. CentOS
>> 5.11 with binutils 2.17). Also, the patch adds some additional
>> documentation to bootstrap-lto option.
>>
>> config/ChangeLog:
>>
>> 2015-03-24  Uros Bizjak  <ubizjak@gmail.com>
>>
>>     PR bootstrap/65537
>>     * bootstrap-lto-noplugin.mk: New build configuration.
>>
>> gcc/ChangeLog:
>>
>> 2015-03-24  Uros Bizjak  <ubizjak@gmail.com>
>>
>>     PR bootstrap/65537
>>     * doc/install.texi (Building a native compiler): Document new
>>     bootstrap-lto-noplugin configuration.  Mention that bootstrap-lto
>>     configuration assumes that the host supports the linker plugin.
>>
>> Patch was bootstrapped and tested on x86_64-linux-gnu (CentOS 5.11)
>> host, configured with --with-build-config=bootstrap-lto build
>> configuration.
>
> and not --with-build-config=bootstrap-lto-noplugin ?

Oh ... with bootstrap-lto-noplugin option. The bootstrap with linker
plugin does not work at all on CentOS 5.11.

Uros.

Re: [PATCH, bootstrap]: Add bootstrap-lto-noplugin build configuration (PR65537)

[Jan Hubicka]

> Hello!
> 
> Attached patch introduces bootstrap-lto-noplugin bootstrap
> configuration for hosts that do not support linker plugin (e.g. CentOS
> 5.11 with binutils 2.17). Also, the patch adds some additional
> documentation to bootstrap-lto option.
> 
> config/ChangeLog:
> 
> 2015-03-24  Uros Bizjak  <ubizjak@gmail.com>
> 
>     PR bootstrap/65537
>     * bootstrap-lto-noplugin.mk: New build configuration.
> 
> gcc/ChangeLog:
> 
> 2015-03-24  Uros Bizjak  <ubizjak@gmail.com>
> 
>     PR bootstrap/65537
>     * doc/install.texi (Building a native compiler): Document new
>     bootstrap-lto-noplugin configuration.  Mention that bootstrap-lto
>     configuration assumes that the host supports the linker plugin.
> 
> Patch was bootstrapped and tested on x86_64-linux-gnu (CentOS 5.11)
> host, configured with --with-build-config=bootstrap-lto build
> configuration.
> 
> OK for mainline?
> Index: gcc/doc/install.texi
> ===================================================================
> --- gcc/doc/install.texi	(revision 221636)
> +++ gcc/doc/install.texi	(working copy)
> @@ -2519,8 +2519,14 @@
>  @item @samp{bootstrap-lto}
>  Enables Link-Time Optimization for host tools during bootstrapping.
>  @samp{BUILD_CONFIG=bootstrap-lto} is equivalent to adding
> -@option{-flto} to @samp{BOOT_CFLAGS}.
> +@option{-flto} to @samp{BOOT_CFLAGS}.  This option assumes that the host
> +supports the linker plugin (e.g. GNU ld version 2.21 or later or GNU gold
> +version 2.21 or later).
>  
> +@item @samp{bootstrap-lto-noplugin}
> +This option is similar to @code{bootstrap-lto}, but is intended for
> +hosts that do not support the linker plugin.

Can you, please, add a note that without linker plugin the static libraries are
not compiled with linktime optimization. Because GCC middle-end and backend is
in libbackend.a it means that only (part of) the frontend is actually LTO
optimized?

Currently it seems bit too welcoming to skip the linker update.

Honza
> +
>  @item @samp{bootstrap-debug}
>  Verifies that the compiler generates the same executable code, whether
>  or not it is asked to emit debug information.  To this end, this

Re: [PATCH, bootstrap]: Add bootstrap-lto-noplugin build configuration (PR65537)

[Uros Bizjak]

On Thu, Mar 26, 2015 at 2:11 AM, Jan Hubicka <hubicka@ucw.cz> wrote:
>> Hello!
>>
>> Attached patch introduces bootstrap-lto-noplugin bootstrap
>> configuration for hosts that do not support linker plugin (e.g. CentOS
>> 5.11 with binutils 2.17). Also, the patch adds some additional
>> documentation to bootstrap-lto option.

[...]

> Can you, please, add a note that without linker plugin the static libraries are
> not compiled with linktime optimization. Because GCC middle-end and backend is
> in libbackend.a it means that only (part of) the frontend is actually LTO
> optimized?

Thanks, I have added following text to the description:

--cut here--
 @item @samp{bootstrap-lto-noplugin}
 This option is similar to @code{bootstrap-lto}, but is intended for
-hosts that do not support the linker plugin.
+hosts that do not support the linker plugin. Please note that static
+libraries are not compiled with link time optimizations without
+linker plugin.  Since GCC middle-end and back-end are in libbackend.a,
+it means that only part of the frontend is actually LTO optimized.
--cut here--

Uros.

Re: [PATCH, bootstrap]: Add bootstrap-lto-noplugin build configuration (PR65537)

[Gerald Pfeifer]

On Thu, 26 Mar 2015, Uros Bizjak wrote:
> Thanks, I have added following text to the description:
> 
> --cut here--
>  @item @samp{bootstrap-lto-noplugin}
>  This option is similar to @code{bootstrap-lto}, but is intended for
> -hosts that do not support the linker plugin.
> +hosts that do not support the linker plugin. Please note that static
> +libraries are not compiled with link time optimizations without
> +linker plugin.  Since GCC middle-end and back-end are in libbackend.a,
> +it means that only part of the frontend is actually LTO optimized.
> --cut here--

I believe there were a couple of issues (link time should be link-time
when it's an adjective, middle-end and back-end on the other hand lose
the the dash when used as a noun,...) and I rewrote this a bit.

Thoughts on the below?  Sandra?

Gerald

2015-04-06  Gerald Pfeifer  <gerald@pfeifer.com>

	* doc/install.texi (bootstrap-lto-noplugin): Rewrite. 

Index: doc/install.texi
===================================================================
--- doc/install.texi	(revision 221832)
+++ doc/install.texi	(working copy)
@@ -2525,10 +2525,10 @@
 
 @item @samp{bootstrap-lto-noplugin}
 This option is similar to @code{bootstrap-lto}, but is intended for
-hosts that do not support the linker plugin. Please note that static
-libraries are not compiled with link time optimizations without
-linker plugin.  Since GCC middle-end and back-end are in libbackend.a,
-it means that only part of the frontend is actually LTO optimized.
+hosts that do not support the linker plugin.  Without the linker plugin 
+static libraries are not compiled with link-time optimizations.  Since 
+the GCC middle end and back end are in @file{libbackend.a} this means
+that only the frontend is actually LTO optimized.
 
 @item @samp{bootstrap-debug}
 Verifies that the compiler generates the same executable code, whether

Re: [PATCH, bootstrap]: Add bootstrap-lto-noplugin build configuration (PR65537)

[Sandra Loosemore]

On 04/06/2015 06:45 AM, Gerald Pfeifer wrote:
>
> Thoughts on the below?  Sandra?
>
> ===================================================================
> --- doc/install.texi	(revision 221832)
> +++ doc/install.texi	(working copy)
> @@ -2525,10 +2525,10 @@
>
>   @item @samp{bootstrap-lto-noplugin}
>   This option is similar to @code{bootstrap-lto}, but is intended for
> -hosts that do not support the linker plugin. Please note that static
> -libraries are not compiled with link time optimizations without
> -linker plugin.  Since GCC middle-end and back-end are in libbackend.a,
> -it means that only part of the frontend is actually LTO optimized.
> +hosts that do not support the linker plugin.  Without the linker plugin
> +static libraries are not compiled with link-time optimizations.  Since
> +the GCC middle end and back end are in @file{libbackend.a} this means
> +that only the frontend is actually LTO optimized.

s/frontend/front end/  ??

(Since we have "middle end" and "back end" on the previous line.)

>
>   @item @samp{bootstrap-debug}
>   Verifies that the compiler generates the same executable code, whether
>

-Sandra

Re: [PATCH, bootstrap]: Add bootstrap-lto-noplugin build configuration (PR65537)

[Gerald Pfeifer]

On Mon, 6 Apr 2015, Sandra Loosemore wrote:
> s/frontend/front end/  ??
> 
> (Since we have "middle end" and "back end" on the previous line.)

Absolutely -- I should have caught this.  Is also is in line with 
https://gcc.gnu.org/codingconventions.html.

Here is the updated patch I just committed.

2015-04-08  Gerald Pfeifer  <gerald@pfeifer.com>

	* doc/install.texi (bootstrap-lto-noplugin): Rewrite. 

Index: doc/install.texi
===================================================================
--- doc/install.texi	(revision 221916)
+++ doc/install.texi	(working copy)
@@ -2525,10 +2525,10 @@
 
 @item @samp{bootstrap-lto-noplugin}
 This option is similar to @code{bootstrap-lto}, but is intended for
-hosts that do not support the linker plugin. Please note that static
-libraries are not compiled with link time optimizations without
-linker plugin.  Since GCC middle-end and back-end are in libbackend.a,
-it means that only part of the frontend is actually LTO optimized.
+hosts that do not support the linker plugin.  Without the linker plugin 
+static libraries are not compiled with link-time optimizations.  Since 
+the GCC middle end and back end are in @file{libbackend.a} this means
+that only the front end is actually LTO optimized.
 
 @item @samp{bootstrap-debug}
 Verifies that the compiler generates the same executable code, whether