C++ bootstrap of GCC - still useful ?

C++ bootstrap of GCC - still useful ?

[Toon Moene]

All,

As of a couple of months, I perform a bootstrap-with-C++ 
(--enable-build-with-cxx) daily on my machine between 18:10 and 20:10 UTC.

I see that the build by a C++ compiler has been the subject of the GCC 
Gathering at Google:

C++ style and migration   crowl    writing and using C++ in gcc

It is not quite clear what the outcome of this discussion was.

Is there still interest in daily builds like mine ?

Kind regards,

-- 
Toon Moene - e-mail: toon@moene.org - phone: +31 346 214290
Saturnushof 14, 3738 XG  Maartensdijk, The Netherlands
At home: http://moene.org/~toon/; weather: http://moene.org/~hirlam/
Progress of GNU Fortran: http://gcc.gnu.org/wiki/GFortran#news

Re: C++ bootstrap of GCC - still useful ?

[Gabriel Dos Reis]

On Sat, Jul 9, 2011 at 3:07 PM, Toon Moene <toon@moene.org> wrote:

> Is there still interest in daily builds like mine ?

Yes.  I am wondering why you have to ask the question :-)

-- Gaby

RE: C++ bootstrap of GCC - still useful ?

[Hargett, Matt]

> As of a couple of months, I perform a bootstrap-with-C++
> (--enable-build-with-cxx) daily on my machine between 18:10 and 20:10 UTC.

> Is there still interest in daily builds like mine ?

Absolutely! Especially if you do a profiled-bootstrap and/or LTO bootstrap in that mode. Hopefully this is feasible given the recent improvements in trunk that allowed Mozilla to be built this way.

Even without those things, it's quite useful to make sure it stays working. So, thanks and keep it up :)

Re: C++ bootstrap of GCC - still useful ?

[Ian Lance Taylor]

Toon Moene <toon@moene.org> writes:

> As of a couple of months, I perform a bootstrap-with-C++
> (--enable-build-with-cxx) daily on my machine between 18:10 and 20:10
> UTC.
>
> I see that the build by a C++ compiler has been the subject of the GCC
> Gathering at Google:
>
> C++ style and migration   crowl    writing and using C++ in gcc
>
> It is not quite clear what the outcome of this discussion was.
>
> Is there still interest in daily builds like mine ?

Yes, it's definitely useful.

The immediate blocker to using C++ in gcc is the Ada frontend.
--enable-build-with-cxx and --enable-languages=ada do not work together.

Ian

Re: C++ bootstrap of GCC - still useful ?

[Eric Botcazou]

> The immediate blocker to using C++ in gcc is the Ada frontend.
> --enable-build-with-cxx and --enable-languages=ada do not work together.

Could you elaborate?

-- 
Eric Botcazou

Re: C++ bootstrap of GCC - still useful ?

[Toon Moene]

On 07/10/2011 06:45 AM, Ian Lance Taylor wrote:

> Toon Moene<toon@moene.org>  writes:

>> As of a couple of months, I perform a bootstrap-with-C++
>> (--enable-build-with-cxx) daily on my machine between 18:10 and 20:10
>> UTC.
>>
>> I see that the build by a C++ compiler has been the subject of the GCC
>> Gathering at Google:
>>
>> C++ style and migration   crowl    writing and using C++ in gcc
>>
>> It is not quite clear what the outcome of this discussion was.
>>
>> Is there still interest in daily builds like mine ?
>
> Yes, it's definitely useful.
>
> The immediate blocker to using C++ in gcc is the Ada frontend.
> --enable-build-with-cxx and --enable-languages=ada do not work together.

Ah, OK.

Just drop me a note when a regular test including Ada starts to be 
useful (I probably have to skip some other front end language in favor 
Ada to stay within the two hour elapsed time window between two weather 
forecasting runs).

BTW, the ultimate reason I asked was that it turned out that running an 
ordinary quad core PC to the max doesn't come for free.

Last month I got past year's electricity bill - it turns out that I am 
now (16 hours of weather forecasting and 4 hours of GCC bootstrapping 
per day) using 3200 KWh a year - to the tune of 1100 Euros.

So the question whether a run is useful is certainly relevant :-)

-- 
Toon Moene - e-mail: toon@moene.org - phone: +31 346 214290
Saturnushof 14, 3738 XG  Maartensdijk, The Netherlands
At home: http://moene.org/~toon/; weather: http://moene.org/~hirlam/
Progress of GNU Fortran: http://gcc.gnu.org/wiki/GFortran#news

Re: C++ bootstrap of GCC - still useful ?

[Gabriel Dos Reis]

On Sun, Jul 10, 2011 at 1:03 PM, Toon Moene <toon@moene.org> wrote:

> BTW, the ultimate reason I asked was that it turned out that running an
> ordinary quad core PC to the max doesn't come for free.
>
> Last month I got past year's electricity bill - it turns out that I am now
> (16 hours of weather forecasting and 4 hours of GCC bootstrapping per day)
> using 3200 KWh a year - to the tune of 1100 Euros.

Ouch! :-/

> So the question whether a run is useful is certainly relevant :-)

Indeed :-)

Re: C++ bootstrap of GCC - still useful ?

[Laurent GUERBY]

On Sun, 2011-07-10 at 20:03 +0200, Toon Moene wrote:
> On 07/10/2011 06:45 AM, Ian Lance Taylor wrote:
> 
> > Toon Moene<toon@moene.org>  writes:
> 
> >> As of a couple of months, I perform a bootstrap-with-C++
> >> (--enable-build-with-cxx) daily on my machine between 18:10 and 20:10
> >> UTC.
> >>
> >> I see that the build by a C++ compiler has been the subject of the GCC
> >> Gathering at Google:
> >>
> >> C++ style and migration   crowl    writing and using C++ in gcc
> >>
> >> It is not quite clear what the outcome of this discussion was.
> >>
> >> Is there still interest in daily builds like mine ?
> >
> > Yes, it's definitely useful.
> >
> > The immediate blocker to using C++ in gcc is the Ada frontend.
> > --enable-build-with-cxx and --enable-languages=ada do not work together.
> 
> Ah, OK.
> 
> Just drop me a note when a regular test including Ada starts to be 
> useful (I probably have to skip some other front end language in favor 
> Ada to stay within the two hour elapsed time window between two weather 
> forecasting runs).
> 
> BTW, the ultimate reason I asked was that it turned out that running an 
> ordinary quad core PC to the max doesn't come for free.
> 
> Last month I got past year's electricity bill - it turns out that I am 
> now (16 hours of weather forecasting and 4 hours of GCC bootstrapping 
> per day) using 3200 KWh a year - to the tune of 1100 Euros.
> 
> So the question whether a run is useful is certainly relevant :-)

Hi,

Since I pay the electricty bill of some compile farm machines
I understand you here :).

New generation of hardware has made significant progress on energy
efficiency: my latest built PC is a Intel core i7 2600 4 cores 8 threads
3.4 GHz 4x4 GB of RAM with 40 GB SSD + 2TB HDD, 80+ gold PSU and it
idles around 30W and uses 110W full CPU load. PC cost is around 800 EUR
in France (19.6% VAT included). 

According to your data it should reduce your bill by a factor of three
(365W => 110W), so it should pay itself in around a year: 720 EUR less
on your yearly electricity bill, assuming you counted only your PC power
consumption in your figures. And bonus nearly no noise in a case with 2
or 3 120mm fans.

I haven't had a chance to test AMD A8 processors but I will do soon.

Sincerely,

Laurent

Re: C++ bootstrap of GCC - still useful ?

[Ian Lance Taylor]

Eric Botcazou <ebotcazou@adacore.com> writes:

>> The immediate blocker to using C++ in gcc is the Ada frontend.
>> --enable-build-with-cxx and --enable-languages=ada do not work together.
>
> Could you elaborate?

When I configure with
    --enable-build-with-cxx --enable-languages=c,c++,ada
I get the appended.  The problem is that the Ada code is looking for C
symbol names but the names in the .o files are mangled for C++.

Ian


gcc -static-libgcc  -o gnatbind ada/b_gnatb.o ada/adaint.o ada/argv.o ada/exit.o ada/cio.o ada/cstreams.o ada/env.o ada/final.o ada/init.o ada/initialize.o ada/seh_init.o ada/link.o ada/targext.o ada/raise.o ada/tracebak.o ada/ada.o ada/a-clrefi.o ada/a-comlin.o ada/a-elchha.o ada/a-except.o ada/ali-util.o ada/ali.o ada/alloc.o ada/aspects.o ada/atree.o ada/bcheck.o ada/binde.o ada/binderr.o ada/bindgen.o ada/bindusg.o ada/butil.o ada/casing.o ada/csets.o ada/debug.o ada/einfo.o ada/elists.o ada/err_vars.o ada/errout.o ada/erroutc.o ada/fmap.o ada/fname.o ada/g-hesora.o ada/g-htable.o ada/s-os_lib.o ada/s-string.o ada/gnat.o ada/gnatbind.o ada/gnatvsn.o ada/hostparm.o ada/interfac.o ada/lib.o ada/namet.o ada/nlists.o ada/opt.o ada/osint-b.o ada/osint.o ada/output.o ada/rident.o ada/s-addope.o ada/s-assert.o ada/s-carun8.o ada/s-casuti.o ada/s-conca2.o ada/s-conca3.o ada/s-conca4.o ada/s-conca5.o ada/s-conca6.o ada/s-conca7.o ada/s-conca8.o ada/s-conca9.o ada/s-crc32.o ada/s-crtl.o ada/s-except.o ada/s-exctab.o ada/s-htable.o ada/s-imenne.o ada/s-imgenu.o ada/s-mastop.o ada/s-memory.o ada/s-parame.o ada/s-restri.o ada/s-secsta.o ada/s-soflin.o ada/s-sopco3.o ada/s-sopco4.o ada/s-sopco5.o ada/s-stache.o ada/s-stalib.o ada/s-stoele.o ada/s-strhas.o ada/s-strops.o ada/s-traceb.o ada/s-traent.o ada/s-unstyp.o ada/s-utf_32.o ada/s-wchcnv.o ada/s-wchcon.o ada/s-wchjis.o ada/scng.o ada/scans.o ada/scil_ll.o ada/sdefault.o ada/sem_aux.o ada/sinfo.o ada/sinput.o ada/sinput-c.o ada/snames.o ada/stand.o ada/stringt.o ada/switch-b.o ada/switch.o ada/style.o ada/styleg.o ada/stylesw.o ada/system.o ada/table.o ada/targparm.o ada/tree_io.o ada/types.o ada/uintp.o ada/uname.o ada/urealp.o ada/widechar.o ggc-none.o libcommon-target.a libcommon.a ../libcpp/libcpp.a   ../libiberty/libiberty.a ../libdecnumber/libdecnumber.a   -g
ada/b_gnatb.o: In function `adainit':
/home/ian/gcc/build-with-cxx-ada/gcc/ada/b_gnatb.adb:122: undefined reference to `__gnat_install_handler'
ada/b_gnatb.o: In function `main':
/home/ian/gcc/build-with-cxx-ada/gcc/ada/b_gnatb.adb:250: undefined reference to `__gnat_initialize'
/home/ian/gcc/build-with-cxx-ada/gcc/ada/b_gnatb.adb:255: undefined reference to `__gnat_finalize'
ada/init.o: In function `__gnat_error_handler':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/init.c:661: undefined reference to `ada__exceptions__raise_from_signal_handler(Exception_Data*, char const*)'
ada/a-comlin.o: In function `ada__command_line__argument':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/a-comlin.adb:75: undefined reference to `__gnat_len_arg'
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/a-comlin.adb:77: undefined reference to `__gnat_fill_arg'
ada/a-comlin.o: In function `ada__command_line__argument_count':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/a-comlin.adb:94: undefined reference to `__gnat_arg_count'
ada/a-comlin.o: In function `ada__command_line__command_name':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/a-comlin.adb:123: undefined reference to `__gnat_len_arg'
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/a-comlin.adb:126: undefined reference to `__gnat_fill_arg'
ada/a-elchha.o: In function `__gnat_last_chance_handler':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/a-elchha.adb:137: undefined reference to `__gnat_unhandled_terminate'
ada/a-except.o: In function `__gnat_to_stderr_char':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/a-except.adb:1314: undefined reference to `put_char_stderr'
ada/a-except.o: In function `ada__exceptions__process_raise_exception':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/a-except.adb:748: undefined reference to `_gnat_builtin_longjmp'
ada/fmap.o: In function `fmap__update_mapping_file':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/fmap.adb:498: undefined reference to `__gnat_lseek'
ada/s-os_lib.o: In function `system__os_lib__copy_file':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/s-os_lib.adb:569: undefined reference to `__gnat_lseek'
ada/s-os_lib.o: In function `system__os_lib__copy_file__copy_to':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/s-os_lib.adb:482: undefined reference to `__gnat_copy_attribs'
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/s-os_lib.adb:487: undefined reference to `__gnat_copy_attribs'
ada/s-os_lib.o: In function `system__os_lib__copy_time_stamps':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/s-os_lib.adb:637: undefined reference to `__gnat_copy_attribs'
ada/s-os_lib.o: In function `system__os_lib__create_file__2':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/s-os_lib.adb:679: undefined reference to `__gnat_open_create'
ada/s-os_lib.o: In function `system__os_lib__create_new_file__2':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/s-os_lib.adb:708: undefined reference to `__gnat_open_new'
ada/s-os_lib.o: In function `system__os_lib__create_output_text_file':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/s-os_lib.adb:737: undefined reference to `__gnat_create_output_file'
ada/s-os_lib.o: In function `system__os_lib__create_temp_file':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/s-os_lib.adb:754: undefined reference to `__gnat_open_new_temp'
ada/s-os_lib.o: In function `system__os_lib__create_temp_file_internal__create_new_output_text_file':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/s-os_lib.adb:809: undefined reference to `__gnat_create_output_file_new'
ada/s-os_lib.o: In function `system__os_lib__delete_file__2':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/s-os_lib.adb:908: undefined reference to `__gnat_unlink'
ada/s-os_lib.o: In function `system__os_lib__file_time_stamp__2':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/s-os_lib.adb:930: undefined reference to `__gnat_file_time_fd'
ada/s-os_lib.o: In function `system__os_lib__file_time_stamp__3':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/s-os_lib.adb:937: undefined reference to `__gnat_file_time_name'
ada/s-os_lib.o: In function `system__os_lib__get_debuggable_suffix':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/s-os_lib.adb:964: undefined reference to `__gnat_get_debuggable_suffix_ptr'
ada/s-os_lib.o: In function `system__os_lib__get_executable_suffix':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/s-os_lib.adb:991: undefined reference to `__gnat_get_executable_suffix_ptr'
ada/s-os_lib.o: In function `system__os_lib__get_object_suffix':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/s-os_lib.adb:1018: undefined reference to `__gnat_get_object_suffix_ptr'
ada/s-os_lib.o: In function `system__os_lib__getenv':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/s-os_lib.adb:1139: undefined reference to `__gnat_getenv'
ada/s-os_lib.o: In function `system__os_lib__gm_split':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/s-os_lib.adb:1281: undefined reference to `__gnat_to_gm_time'
ada/s-os_lib.o: In function `system__os_lib__is_absolute_path':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/s-os_lib.adb:1330: undefined reference to `__gnat_is_absolute_path'
ada/s-os_lib.o: In function `system__os_lib__is_directory__2':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/s-os_lib.adb:1341: undefined reference to `__gnat_is_directory'
ada/s-os_lib.o: In function `system__os_lib__is_readable_file__2':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/s-os_lib.adb:1360: undefined reference to `__gnat_is_readable_file'
ada/s-os_lib.o: In function `system__os_lib__is_executable_file__2':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/s-os_lib.adb:1379: undefined reference to `__gnat_is_executable_file'
ada/s-os_lib.o: In function `system__os_lib__is_regular_file__2':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/s-os_lib.adb:1398: undefined reference to `__gnat_is_regular_file'
ada/s-os_lib.o: In function `system__os_lib__is_symbolic_link__2':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/s-os_lib.adb:1417: undefined reference to `__gnat_is_symbolic_link'
ada/s-os_lib.o: In function `system__os_lib__is_writable_file__2':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/s-os_lib.adb:1436: undefined reference to `__gnat_is_writable_file'
ada/s-os_lib.o: In function `system__os_lib__locate_exec_on_path':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/s-os_lib.adb:1469: undefined reference to `__gnat_locate_exec_on_path'
ada/s-os_lib.o: In function `system__os_lib__locate_regular_file__2':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/s-os_lib.adb:1515: undefined reference to `__gnat_locate_regular_file'
ada/s-os_lib.o: In function `system__os_lib__non_blocking_spawn__2':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/s-os_lib.adb:1592: undefined reference to `__gnat_dup'
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/s-os_lib.adb:1593: undefined reference to `__gnat_dup2'
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/s-os_lib.adb:1596: undefined reference to `__gnat_dup'
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/s-os_lib.adb:1597: undefined reference to `__gnat_dup2'
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/s-os_lib.adb:1606: undefined reference to `__gnat_dup2'
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/s-os_lib.adb:1609: undefined reference to `__gnat_dup2'
ada/s-os_lib.o: In function `system__os_lib__normalize_pathname':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/s-os_lib.adb:1788: undefined reference to `__gnat_get_file_names_case_sensitive'
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/s-os_lib.adb:1937: undefined reference to `__gnat_to_canonical_file_spec'
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/s-os_lib.adb:2171: undefined reference to `__gnat_readlink'
ada/s-os_lib.o: In function `system__os_lib__normalize_pathname__get_directory':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/s-os_lib.adb:1899: undefined reference to `__gnat_get_current_dir'
ada/s-os_lib.o: In function `system__os_lib__open_read__2':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/s-os_lib.adb:2230: undefined reference to `__gnat_open_read'
ada/s-os_lib.o: In function `system__os_lib__open_read_write__2':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/s-os_lib.adb:2257: undefined reference to `__gnat_open_rw'
ada/s-os_lib.o: In function `system__os_lib__os_exit_default':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/s-os_lib.adb:2290: undefined reference to `__gnat_os_exit'
ada/s-os_lib.o: In function `system__os_lib__rename_file__2':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/s-os_lib.adb:2332: undefined reference to `__gnat_rename'
ada/s-os_lib.o: In function `system__os_lib__set_close_on_exec':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/s-os_lib.adb:2365: undefined reference to `__gnat_set_close_on_exec'
ada/s-os_lib.o: In function `system__os_lib__set_executable':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/s-os_lib.adb:2379: undefined reference to `__gnat_set_executable'
ada/s-os_lib.o: In function `system__os_lib__set_non_readable':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/s-os_lib.adb:2393: undefined reference to `__gnat_set_non_readable'
ada/s-os_lib.o: In function `system__os_lib__set_non_writable':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/s-os_lib.adb:2407: undefined reference to `__gnat_set_non_writable'
ada/s-os_lib.o: In function `system__os_lib__set_readable':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/s-os_lib.adb:2421: undefined reference to `__gnat_set_readable'
ada/s-os_lib.o: In function `system__os_lib__set_writable':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/s-os_lib.adb:2435: undefined reference to `__gnat_set_writable'
ada/s-os_lib.o: In function `system__os_lib__setenv':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/s-os_lib.adb:2456: undefined reference to `__gnat_setenv'
ada/s-os_lib.o: In function `system__os_lib__spawn__3':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/s-os_lib.adb:2497: undefined reference to `__gnat_dup'
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/s-os_lib.adb:2498: undefined reference to `__gnat_dup2'
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/s-os_lib.adb:2501: undefined reference to `__gnat_dup'
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/s-os_lib.adb:2502: undefined reference to `__gnat_dup2'
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/s-os_lib.adb:2511: undefined reference to `__gnat_dup2'
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/s-os_lib.adb:2514: undefined reference to `__gnat_dup2'
ada/s-os_lib.o: In function `system__os_lib__spawn_internal__spawn':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/s-os_lib.adb:2639: undefined reference to `__gnat_portable_spawn'
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/s-os_lib.adb:2641: undefined reference to `__gnat_portable_no_block_spawn'
ada/s-os_lib.o: In function `system__os_lib__wait_process':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/s-os_lib.adb:2710: undefined reference to `__gnat_portable_wait'
ada/gnatbind.o: In function `_ada_gnatbind':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/gnatbind.adb:505: undefined reference to `__gnat_arg_count'
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/gnatbind.adb:507: undefined reference to `__gnat_len_arg'
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/gnatbind.adb:509: undefined reference to `__gnat_fill_arg'
ada/gnatbind.o: In function `gnatbind__check_version_and_help':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/switch.adb:62: undefined reference to `__gnat_arg_count'
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/switch.adb:64: undefined reference to `__gnat_len_arg'
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/switch.adb:66: undefined reference to `__gnat_fill_arg'
ada/gnatbind.o: In function `gnatbind__gnatbind_supports_auto_init':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/gnatbind.adb:119: undefined reference to `__gnat_binder_supports_auto_init'
ada/hostparm.o: In function `hostparm___elabs':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/hostparm.ads:47: undefined reference to `__gnat_vmsp'
ada/opt.o: In function `opt___elabs':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/opt.ads:1902: undefined reference to `get_gcc_version'
ada/osint.o: In function `osint__add_default_search_dirs__get_dirs_from_file':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/osint.adb:363: undefined reference to `__gnat_file_length'
ada/osint.o: In function `osint__add_default_search_dirs__get_libraries_from_registry':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/osint.adb:433: undefined reference to `__gnat_get_libraries_from_registry'
ada/osint.o: In function `osint__executable_prefix':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/osint.adb:981: undefined reference to `__gnat_len_arg'
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/osint.adb:982: undefined reference to `__gnat_fill_arg'
ada/osint.o: In function `osint__file_length':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/osint.adb:1073: undefined reference to `__gnat_file_length_attr'
ada/osint.o: In function `osint__file_time_stamp':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/osint.adb:1087: undefined reference to `__gnat_file_time_name_attr'
ada/osint.o: In function `osint__find_program_name':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/osint.adb:1254: undefined reference to `__gnat_len_arg'
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/osint.adb:1259: undefined reference to `__gnat_fill_arg'
ada/osint.o: In function `osint__get_rts_search_dir':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/osint.adb:1540: undefined reference to `__gnat_get_current_dir'
ada/osint.o: In function `osint__is_directory':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/osint.adb:1679: undefined reference to `__gnat_is_directory_attr'
ada/osint.o: In function `osint__is_executable_file':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/osint.adb:1723: undefined reference to `__gnat_is_executable_file_attr'
ada/osint.o: In function `osint__is_readable_file':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/osint.adb:1736: undefined reference to `__gnat_is_readable_file_attr'
ada/osint.o: In function `osint__is_regular_file':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/osint.adb:1749: undefined reference to `__gnat_is_regular_file_attr'
ada/osint.o: In function `osint__is_symbolic_link':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/osint.adb:1762: undefined reference to `__gnat_is_symbolic_link_attr'
ada/osint.o: In function `osint__is_writable_file':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/osint.adb:1775: undefined reference to `__gnat_is_writable_file_attr'
ada/osint.o: In function `osint__read_default_search_dirs':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/osint.adb:2311: undefined reference to `__gnat_file_length'
ada/osint.o: In function `osint__read_source_file':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/osint.adb:2649: undefined reference to `__gnat_file_length'
ada/osint.o: In function `osint__relocate_path':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/osint.adb:2734: undefined reference to `set_std_prefix'
ada/osint.o: In function `osint__to_canonical_dir_spec':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/osint.adb:2952: undefined reference to `__gnat_to_canonical_dir_spec'
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/osint.adb:2954: undefined reference to `__gnat_to_canonical_dir_spec'
ada/osint.o: In function `osint__to_canonical_file_list':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/osint.adb:3003: undefined reference to `__gnat_to_canonical_file_list_init'
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/osint.adb:3015: undefined reference to `__gnat_to_canonical_file_list_next'
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/osint.adb:3023: undefined reference to `__gnat_to_canonical_file_list_free'
ada/osint.o: In function `osint__to_canonical_file_spec':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/osint.adb:3048: undefined reference to `__gnat_to_canonical_file_spec'
ada/osint.o: In function `osint__to_canonical_path_spec':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/osint.adb:3083: undefined reference to `__gnat_to_canonical_path_spec'
ada/osint.o: In function `osint__to_host_dir_spec':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/osint.adb:3119: undefined reference to `__gnat_to_host_dir_spec'
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/osint.adb:3121: undefined reference to `__gnat_to_host_dir_spec'
ada/osint.o: In function `osint__to_host_file_spec':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/osint.adb:3150: undefined reference to `__gnat_to_host_file_spec'
ada/osint.o: In function `osint__update_path':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/osint.adb:3216: undefined reference to `update_path'
ada/osint.o: In function `osint___elabb':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/osint.adb:3314: undefined reference to `__gnat_size_of_file_attributes'
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/osint.adb:3316: undefined reference to `__gnat_reset_attributes'
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/osint.adb:3318: undefined reference to `__gnat_get_default_identifier_character_set'
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/osint.adb:3319: undefined reference to `__gnat_get_maximum_file_name_length'
ada/osint.o: In function `osint___elabs':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/osint.ads:84: undefined reference to `__gnat_get_file_names_case_sensitive'
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/osint.ads:101: undefined reference to `__gnat_get_env_vars_case_sensitive'
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/osint.ads:698: undefined reference to `__gnat_arg_count'
ada/s-traceb.o: In function `system__traceback__call_chain':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/s-traceb.adb:86: undefined reference to `__gnat_backtrace'
ada/sinput-c.o: In function `sinput__c__load_file':
/home/ian/gcc/build-with-cxx-ada/gcc/../../trunk/gcc/ada/sinput-c.adb:92: undefined reference to `__gnat_file_length'
collect2: ld returned 1 exit status
make[3]: *** [gnatbind] Error 1

Re: C++ bootstrap of GCC - still useful ?

[Arnaud Charlet]

> When I configure with
>     --enable-build-with-cxx --enable-languages=c,c++,ada
> I get the appended.  The problem is that the Ada code is looking for C
> symbol names but the names in the .o files are mangled for C++.

Right, or rather than we want to use the C compiler to compile all those
files (e.g. init.c, argv.c), not the C++ compiler.

Arno

Re: C++ bootstrap of GCC - still useful ?

[Paul Koning]

On Jul 11, 2011, at 12:53 PM, Arnaud Charlet wrote:

>> When I configure with
>>    --enable-build-with-cxx --enable-languages=c,c++,ada
>> I get the appended.  The problem is that the Ada code is looking for C
>> symbol names but the names in the .o files are mangled for C++.
> 
> Right, or rather than we want to use the C compiler to compile all those
> files (e.g. init.c, argv.c), not the C++ compiler.

Isn't 'extern "C" ' the standard way to handle this sort of thing?

	paul

Re: C++ bootstrap of GCC - still useful ?

[Gabriel Dos Reis]

On Mon, Jul 11, 2011 at 11:53 AM, Arnaud Charlet <charlet@adacore.com> wrote:
>> When I configure with
>>     --enable-build-with-cxx --enable-languages=c,c++,ada
>> I get the appended.  The problem is that the Ada code is looking for C
>> symbol names but the names in the .o files are mangled for C++.
>
> Right, or rather than we want to use the C compiler to compile all those
> files (e.g. init.c, argv.c), not the C++ compiler.

Do you want a C compiler for that, or do you in fact just need an

   extern "C"

language specification for those symbols?  I would have thought the latter.

-- Gaby

Re: C++ bootstrap of GCC - still useful ?

[Toon Moene]

On 07/10/2011 11:20 PM, Laurent GUERBY wrote:

> On Sun, 2011-07-10 at 20:03 +0200, Toon Moene wrote:

>> Last month I got past year's electricity bill - it turns out that I am
>> now (16 hours of weather forecasting and 4 hours of GCC bootstrapping
>> per day) using 3200 KWh a year - to the tune of 1100 Euros.
>>
>> So the question whether a run is useful is certainly relevant :-)

> Since I pay the electricity bill of some compile farm machines
> I understand you here :).
>
> New generation of hardware has made significant progress on energy
> efficiency: my latest built PC is a Intel core i7 2600 4 cores 8 threads
> 3.4 GHz 4x4 GB of RAM with 40 GB SSD + 2TB HDD, 80+ gold PSU and it
> idles around 30W and uses 110W full CPU load. PC cost is around 800 EUR
> in France (19.6% VAT included).
>
> According to your data it should reduce your bill by a factor of three
> (365W =>  110W), so it should pay itself in around a year: 720 EUR less
> on your yearly electricity bill, assuming you counted only your PC power
> consumption in your figures. And bonus nearly no noise in a case with 2
> or 3 120mm fans.
>
> I haven't had a chance to test AMD A8 processors but I will do soon.

One of the most frustrating aspects of this is that I cannot just write 
an Invitation To Tender for a 1000-1200 Euro PC (I have been involved 
with that process for KNMI's High Performance Computer now for over 15 
years).

If I could do that, I would be able to:

1) Choose from several vendors.

2) Evaluate both "speed-of-execution" and "energy-efficiency" in a
    consistent way.

3) Evaluate the use of AMD vs Intel processors independent of the
    vendor of choice.

4) Get the vendor to install the Operating-System-of-choice (Debian
    Testing) and run my benchmarks, so that I'll be able to check
    their assumptions.

Instead, what I am currently doing to plan the replacement of the 2007 
vintage machine that runs just two feet away from me, is to:

1) Gather information about upcoming Intel and AMD CPU's.

2) Estimate when they will hit the "Home and Small Business Market".

3) Hope that such a machine will indeed be priced between 1000-1200
    Euro's.

4) Hope that the vendor who delivered me the current machine will have
    a competitive offer (note that I want to stay with my current vendor
    - I yet have to see another PC vendor making a machine that's
    obviously geared towards teenagers storing bittorrent-downloaded
    movies, that actually is able to work 16 hours+ per day on
    *real science* at full capacity without breaking down after years of
    service).

Sigh.

-- 
Toon Moene - e-mail: toon@moene.org - phone: +31 346 214290
Saturnushof 14, 3738 XG  Maartensdijk, The Netherlands
At home: http://moene.org/~toon/; weather: http://moene.org/~hirlam/
Progress of GNU Fortran: http://gcc.gnu.org/wiki/GFortran#news

Re: C++ bootstrap of GCC - still useful ?

[Eric Botcazou]

> When I configure with
>     --enable-build-with-cxx --enable-languages=c,c++,ada
> I get the appended.  The problem is that the Ada code is looking for C
> symbol names but the names in the .o files are mangled for C++.

OK, this is known: a couple of tweaks to the Makefile (to use g++ instead of 
gcc to link) are needed and extern "C" must be added all over the place, see:
  http://gcc.gnu.org/ml/gcc/2009-06/msg00635.html

I can post an updated patch if you want, but saying that the Ada front-end 
blocks the use of C++ in gcc is unfair; it is (and has always been) neutral.

-- 
Eric Botcazou

Re: C++ bootstrap of GCC - still useful ?

[Ian Lance Taylor]

Eric Botcazou <ebotcazou@adacore.com> writes:

>> When I configure with
>>     --enable-build-with-cxx --enable-languages=c,c++,ada
>> I get the appended.  The problem is that the Ada code is looking for C
>> symbol names but the names in the .o files are mangled for C++.
>
> OK, this is known: a couple of tweaks to the Makefile (to use g++ instead of 
> gcc to link) are needed and extern "C" must be added all over the place, see:
>   http://gcc.gnu.org/ml/gcc/2009-06/msg00635.html
>
> I can post an updated patch if you want, but saying that the Ada front-end 
> blocks the use of C++ in gcc is unfair; it is (and has always been) neutral.

My apologies, I didn't mean to attack.  I tried it, and it failed
building Ada.  That's all I meant.

If there is an up to date patch, I'm happy to review it if it would
help.  But perhaps an Ada maintainer would prefer to do the review, I
don't know what the usual policy is as I've never approved an Ada patch.

I have a patch ready to go which would use C++ in stages 2 and 3.  I
can't propose that patch right now because it fails when building Ada.
If we get Ada fixed, I will propose it.

Ian

Re: C++ bootstrap of GCC - still useful ?

[Eric Botcazou]

> If there is an up to date patch, I'm happy to review it if it would
> help.  But perhaps an Ada maintainer would prefer to do the review, I
> don't know what the usual policy is as I've never approved an Ada patch.

The patch is here: http://gcc.gnu.org/ml/gcc-patches/2011-07/msg00845.html

> I have a patch ready to go which would use C++ in stages 2 and 3.  I
> can't propose that patch right now because it fails when building Ada.
> If we get Ada fixed, I will propose it.

OK, let's fix --enable-build-with-cxx with Ada.  Thanks for clarifying.

-- 
Eric Botcazou

Re: C++ bootstrap of GCC - still useful ?

[Ian Lance Taylor]

Eric Botcazou <ebotcazou@adacore.com> writes:

>> If there is an up to date patch, I'm happy to review it if it would
>> help.  But perhaps an Ada maintainer would prefer to do the review, I
>> don't know what the usual policy is as I've never approved an Ada patch.
>
> The patch is here: http://gcc.gnu.org/ml/gcc-patches/2011-07/msg00845.html

Thanks.

I'm not sure that always setting LINKER=$(CXX) in gnattools/Makefile.in
is correct.  It seems to me that that should vary based on
--enable-build-with-cxx, as is done in gcc/Makefile.in.  But I don't
know much about building Ada, and perhaps this is right.

Otherwise the patch looks fine to me, for whatever that is worth.

Ian

Re: C++ bootstrap of GCC - still useful ?

[Eric Botcazou]

> I'm not sure that always setting LINKER=$(CXX) in gnattools/Makefile.in
> is correct.  It seems to me that that should vary based on
> --enable-build-with-cxx, as is done in gcc/Makefile.in.  But I don't
> know much about building Ada, and perhaps this is right.

Good catch, thanks, will fix.

-- 
Eric Botcazou

Re: C++ bootstrap of GCC - still useful ?

[Laurent GUERBY]

On Mon, 2011-07-11 at 13:58 -0700, Ian Lance Taylor wrote:
> Eric Botcazou <ebotcazou@adacore.com> writes:
> 
> >> If there is an up to date patch, I'm happy to review it if it would
> >> help.  But perhaps an Ada maintainer would prefer to do the review, I
> >> don't know what the usual policy is as I've never approved an Ada patch.
> >
> > The patch is here: http://gcc.gnu.org/ml/gcc-patches/2011-07/msg00845.html
> 
> Thanks.
> 
> I'm not sure that always setting LINKER=$(CXX) in gnattools/Makefile.in
> is correct.  It seems to me that that should vary based on
> --enable-build-with-cxx, as is done in gcc/Makefile.in.  But I don't
> know much about building Ada, and perhaps this is right.

Hi,

Paolo did suggest something like that:

http://gcc.gnu.org/ml/gcc/2009-06/msg00639.html
<<
I think you should rather do

	"CC=../../xgcc -B../../" \
+	"CXX=../../g++ -B../../" \
        "CFLAGS=$(CFLAGS) $(WARN_CFLAGS)" \
+       "CXXFLAGS=$(CXXFLAGS) $(WARN_CFLAGS)" \

and copy the setting of COMPILER and LINKER from gcc/Makefile.in into
gcc/ada/gcc-interface/Makefile.in:

ENABLE_BUILD_WITH_CXX = @ENABLE_BUILD_WITH_CXX@
ifneq ($(ENABLE_BUILD_WITH_CXX),yes)
COMPILER = $(CC)
COMPILER_FLAGS = $(CFLAGS)
LINKER = $(CC)
LINKER_FLAGS = $(CFLAGS)
else
COMPILER = $(CXX)
COMPILER_FLAGS = $(CXXFLAGS)
LINKER = $(CXX)
LINKER_FLAGS = $(CXXFLAGS)
endif

Paolo
>>

Now I don't know if we intend to support build without CXX
in the near future :).

Sincerely,

Laurent

Re: C++ bootstrap of GCC - still useful ?

[Eric Botcazou]

> Paolo did suggest something like that:
>
> http://gcc.gnu.org/ml/gcc/2009-06/msg00639.html
> <<
> I think you should rather do
>
> 	"CC=../../xgcc -B../../" \
> +	"CXX=../../g++ -B../../" \
>         "CFLAGS=$(CFLAGS) $(WARN_CFLAGS)" \
> +       "CXXFLAGS=$(CXXFLAGS) $(WARN_CFLAGS)" \
>
> and copy the setting of COMPILER and LINKER from gcc/Makefile.in into
> gcc/ada/gcc-interface/Makefile.in:
>
> ENABLE_BUILD_WITH_CXX = @ENABLE_BUILD_WITH_CXX@
> ifneq ($(ENABLE_BUILD_WITH_CXX),yes)
> COMPILER = $(CC)
> COMPILER_FLAGS = $(CFLAGS)
> LINKER = $(CC)
> LINKER_FLAGS = $(CFLAGS)
> else
> COMPILER = $(CXX)
> COMPILER_FLAGS = $(CXXFLAGS)
> LINKER = $(CXX)
> LINKER_FLAGS = $(CXXFLAGS)
> endif

I'm not sure because I don't think we want to compile the C files of the Ada 
runtime with the C++ compiler.  We want to do that only for the compiler.

-- 
Eric Botcazou

Re: C++ bootstrap of GCC - still useful ?

[Arnaud Charlet]

> I'm not sure because I don't think we want to compile the C files of the Ada
> runtime with the C++ compiler.  We want to do that only for the compiler.

Right, we definitely don't want to use the C++ compiler for building the
Ada run-time.

Arno

Re: C++ bootstrap of GCC - still useful ?

[Paolo Bonzini]

On 07/12/2011 08:54 AM, Arnaud Charlet wrote:
>> I'm not sure because I don't think we want to compile the C files of the Ada
>> >  runtime with the C++ compiler.  We want to do that only for the compiler.
> 
> Right, we definitely don't want to use the C++ compiler for building the
> Ada run-time.

But apparently they already are (when building the compiler), otherwise
the patch in http://gcc.gnu.org/ml/gcc/2009-06/txt00004.txt would make
no sense:

Index: gcc/ada/env.c
===================================================================
--- gcc/ada/env.c	(revision 148953)
+++ gcc/ada/env.c	(working copy)
@@ -29,6 +29,11 @@
  *                                                                          *
  ****************************************************************************/
 
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #ifdef IN_RTS
 #include "tconfig.h"
 #include "tsystem.h"
@@ -313,3 +318,7 @@
   clearenv ();
 #endif
 }
+
+#ifdef __cplusplus
+}
+#endif


Perhaps it is better to always build those files with cc, perhaps not.
Since there are two versions of the Ada RTL, the one in the compiler and
the one in libada, my questions are:

1) Do they share any object files when not cross-compiling?

2) If not, is using C++ for the former okay?


If the answers are "no" and "yes" respectively, I still think a patch
like the one I suggested, where the host files in gcc/ are uniformly
compiled with C++, is preferrable. You do need to force usage of a C
compiler when compiling libada:

Index: Makefile.in
===================================================================
--- Makefile.in	(revision 169877)
+++ Makefile.in	(working copy)
@@ -2451,6 +2451,7 @@ gnatlib: ../stamp-gnatlib1-$(RTSDIR) ../
 	$(MAKE) -C $(RTSDIR) \
 		CC="`echo \"$(GCC_FOR_TARGET)\" \
 		| sed -e 's,\./xgcc,../../xgcc,' -e 's,-B\./,-B../../,'`" \
+		ENABLE_BUILD_WITH_CXX=no \
 	        INCLUDES="$(INCLUDES_FOR_SUBDIR) -I./../.." \
                 CFLAGS="$(GNATLIBCFLAGS_FOR_C)" \
 	        FORCE_DEBUG_ADAFLAGS="$(FORCE_DEBUG_ADAFLAGS)" \
@@ -2459,6 +2460,7 @@ gnatlib: ../stamp-gnatlib1-$(RTSDIR) ../
 	$(MAKE) -C $(RTSDIR) \
 		CC="`echo \"$(GCC_FOR_TARGET)\" \
 		| sed -e 's,\./xgcc,../../xgcc,' -e 's,-B\./,-B../../,'`" \
+		ENABLE_BUILD_WITH_CXX=no \
 	        ADA_INCLUDES="" \
                 CFLAGS="$(GNATLIBCFLAGS)" \
 	        ADAFLAGS="$(GNATLIBFLAGS)" \


And of course extern "C" needs to be added to the headers, so that public
symbols used by compiled Ada source are not mangled. However, static and
private symbols need not be extern "C".

Paolo

Re: C++ bootstrap of GCC - still useful ?

[Paolo Bonzini]

On 07/12/2011 08:54 AM, Arnaud Charlet wrote:
>> I'm not sure because I don't think we want to compile the C files of the Ada
>> >  runtime with the C++ compiler.  We want to do that only for the compiler.
> 
> Right, we definitely don't want to use the C++ compiler for building the
> Ada run-time.

But apparently they already are (when building the compiler), otherwise
the patch in http://gcc.gnu.org/ml/gcc/2009-06/txt00004.txt would make
no sense:

Index: gcc/ada/env.c
===================================================================
--- gcc/ada/env.c	(revision 148953)
+++ gcc/ada/env.c	(working copy)
@@ -29,6 +29,11 @@
  *                                                                          *
  ****************************************************************************/
 
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #ifdef IN_RTS
 #include "tconfig.h"
 #include "tsystem.h"
@@ -313,3 +318,7 @@
   clearenv ();
 #endif
 }
+
+#ifdef __cplusplus
+}
+#endif


Perhaps it is better to always build those files with cc, perhaps not.
Since there are two versions of the Ada RTL, the one in the compiler and
the one in libada, my questions are:

1) Do they share any object files when not cross-compiling?

2) If not, is using C++ for the former okay?


If the answers are "no" and "yes" respectively, I still think a patch
like the one I suggested, where the host files in gcc/ are uniformly
compiled with C++, is preferrable. You do need to force usage of a C
compiler when compiling libada:

Index: Makefile.in
===================================================================
--- Makefile.in	(revision 169877)
+++ Makefile.in	(working copy)
@@ -2451,6 +2451,7 @@ gnatlib: ../stamp-gnatlib1-$(RTSDIR) ../
 	$(MAKE) -C $(RTSDIR) \
 		CC="`echo \"$(GCC_FOR_TARGET)\" \
 		| sed -e 's,\./xgcc,../../xgcc,' -e 's,-B\./,-B../../,'`" \
+		ENABLE_BUILD_WITH_CXX=no \
 	        INCLUDES="$(INCLUDES_FOR_SUBDIR) -I./../.." \
                 CFLAGS="$(GNATLIBCFLAGS_FOR_C)" \
 	        FORCE_DEBUG_ADAFLAGS="$(FORCE_DEBUG_ADAFLAGS)" \
@@ -2459,6 +2460,7 @@ gnatlib: ../stamp-gnatlib1-$(RTSDIR) ../
 	$(MAKE) -C $(RTSDIR) \
 		CC="`echo \"$(GCC_FOR_TARGET)\" \
 		| sed -e 's,\./xgcc,../../xgcc,' -e 's,-B\./,-B../../,'`" \
+		ENABLE_BUILD_WITH_CXX=no \
 	        ADA_INCLUDES="" \
                 CFLAGS="$(GNATLIBCFLAGS)" \
 	        ADAFLAGS="$(GNATLIBFLAGS)" \


And of course extern "C" needs to be added to the headers, so that public
symbols used by compiled Ada source are not mangled. However, static and
private symbols need not be extern "C".

Paolo

Re: C++ bootstrap of GCC - still useful ?

[Eric Botcazou]

> Right, we definitely don't want to use the C++ compiler for building the
> Ada run-time.

OK, so the only needed Makefile change is to gcc-interface/Make-lang.in:

Index: ada/gcc-interface/Make-lang.in
===================================================================
--- ada/gcc-interface/Make-lang.in	(revision 176072)
+++ ada/gcc-interface/Make-lang.in	(working copy)
@@ -104,7 +104,7 @@ ADA_TOOLS_FLAGS_TO_PASS=\
 	"GNATLINK=../../gnatlink"	\
 	"GNATBIND=../../gnatbind"
 
-GCC_LINK=$(CC) -static-libgcc $(LDFLAGS)
+GCC_LINK=$(LINKER) $(ALL_LINKERFLAGS) -static-libgcc $(LDFLAGS)
 
 # Lists of files for various purposes.
 

I'm not sure about the long-term interaction with -static-libgcc here, but this 
works currently on Linux so let's keep it for now.

And this means that the initial version adds superfluous extern "C" blocks, I'm 
going to clean it up.

-- 
Eric Botcazou

Re: C++ bootstrap of GCC - still useful ?

[Eric Botcazou]

> Perhaps it is better to always build those files with cc, perhaps not.
> Since there are two versions of the Ada RTL, the one in the compiler and
> the one in libada, my questions are:
>
> 1) Do they share any object files when not cross-compiling?
>
> 2) If not, is using C++ for the former okay?

There aren't really 2 versions and there aren't shared in any case.

> If the answers are "no" and "yes" respectively, I still think a patch
> like the one I suggested, where the host files in gcc/ are uniformly
> compiled with C++, is preferrable.

But your patch isn't necessary to do that, the C files are already compiled 
with the C++ compiler as of today; the only issue is at the linking stage.

-- 
Eric Botcazou

Re: C++ bootstrap of GCC - still useful ?

[Arnaud Charlet]

> But apparently they already are (when building the compiler), otherwise

That's different: some parts of the run-time is used with a native compiler to
bootstrap GNAT.

The GNAT run-time is built separately using the target compiler (potentially
different from the native compiler), so bootstrapping and building the
run-time is done separately, using different compilers and different options.

Arno

Re: C++ bootstrap of GCC - still useful ?

[Paolo Bonzini]

On 07/12/2011 10:00 AM, Eric Botcazou wrote:
> But your patch isn't necessary to do that, the C files are already compiled
> with the C++ compiler as of today; the only issue is at the linking stage.

The problem is that the patches links gnattools unconditionally with 
g++.  It should depend on --enable-build-with-cxx instead.

Paolo

Re: C++ bootstrap of GCC - still useful ?

[Eric Botcazou]

> The problem is that the patches links gnattools unconditionally with
> g++.  It should depend on --enable-build-with-cxx instead.

Yes, that part was wrong, it will be dropped, we don't want to use g++ here.

-- 
Eric Botcazou

Re: C++ bootstrap of GCC - still useful ?

[Paul Koning]

On Jul 12, 2011, at 2:54 AM, Arnaud Charlet wrote:

>> I'm not sure because I don't think we want to compile the C files of the Ada
>> runtime with the C++ compiler.  We want to do that only for the compiler.
> 
> Right, we definitely don't want to use the C++ compiler for building the
> Ada run-time.

Why not?  If extern "C" is used correctly, the result will work just the same, and the improved type checking etc. would be an asset here just as it is elsewhere.

	paul

Re: C++ bootstrap of GCC - still useful ?

[Arnaud Charlet]

> Why not?  If extern "C" is used correctly, the result will work just the same,
> and the improved type checking etc. would be an asset here just as it is
> elsewhere.

We don't use much C code, so the extra benefits wouldn't really be useful
to us (we already get much more benefits by having most of the Ada run-time
written in Ada), and having to deal with mixed C++/Ada by default in the
Ada run-time can bring its own share or complexity that we shouldn't have
to deal with by default.

In addition, the GNAT run-time is built for many cross targets where requiring
a cross C++ compiler would add lots of extra pain.

Requiring a C++ native compiler for bootstrap is one thing (already an
extra pain on some platforms), requiring a C++ cross compiler for building the
run-time is just not an acceptable requirement.

Arno

Re: C++ bootstrap of GCC - still useful ?

[Paul Koning]

On Jul 12, 2011, at 6:56 AM, Arnaud Charlet wrote:

>> Why not?  If extern "C" is used correctly, the result will work just the same,
>> and the improved type checking etc. would be an asset here just as it is
>> elsewhere.
> 
> We don't use much C code, so the extra benefits wouldn't really be useful
> to us (we already get much more benefits by having most of the Ada run-time
> written in Ada), and having to deal with mixed C++/Ada by default in the
> Ada run-time can bring its own share or complexity that we shouldn't have
> to deal with by default.
> 
> In addition, the GNAT run-time is built for many cross targets where requiring
> a cross C++ compiler would add lots of extra pain.
> 
> Requiring a C++ native compiler for bootstrap is one thing (already an
> extra pain on some platforms), requiring a C++ cross compiler for building the
> run-time is just not an acceptable requirement.

Thanks for the explanation, that makes perfect sense.

	paul