From: Richard Earnshaw <rearnsha@arm.com>
To: Michael Hope <michael.hope@linaro.org>
Cc: Carlos O'Donell <carlos@systemhalted.org>,
GCC Patches <gcc-patches@gcc.gnu.org>,
"cross-distro@lists.linaro.org" <cross-distro@lists.linaro.org>,
"libc-ports@sourceware.org" <libc-ports@sourceware.org>
Subject: Re: [PATCH v2] ARM: Use different linker path for hardfloat ABI
Date: Tue, 01 May 2012 08:52:00 -0000 [thread overview]
Message-ID: <4F9FA448.6090509@arm.com> (raw)
In-Reply-To: <CANLjY-nhVTqr1_xrM7NpyOnyWYZkT4hpWZJb2VKDAGVvSaf8Aw@mail.gmail.com>
On 30/04/12 22:47, Michael Hope wrote:
> On 1 May 2012 03:24, Richard Earnshaw <rearnsha@arm.com> wrote:
>> On 27/04/12 00:27, Michael Hope wrote:
>>> On 27 April 2012 08:20, Carlos O'Donell <carlos@systemhalted.org> wrote:
>>>> On Mon, Apr 23, 2012 at 5:36 PM, Michael Hope <michael.hope@linaro.org> wrote:
>>>>> 2012-04-24 Michael Hope <michael.hope@linaro.org>
>>>>> Richard Earnshaw <rearnsha@arm.com>
>>>>>
>>>>> * config/arm/linux-eabi.h (GLIBC_DYNAMIC_LINKER_SOFT_FLOAT): Define.
>>>>> (GLIBC_DYNAMIC_LINKER_HARD_FLOAT): Define.
>>>>> (GLIBC_DYNAMIC_LINKER_DEFAULT): Define.
>>>>> (GLIBC_DYNAMIC_LINKER): Redefine to use the hard float path.
>>>>>
>>>>> diff --git a/gcc/config/arm/linux-eabi.h b/gcc/config/arm/linux-eabi.h
>>>>> index 80bd825..2ace6f0 100644
>>>>> --- a/gcc/config/arm/linux-eabi.h
>>>>> +++ b/gcc/config/arm/linux-eabi.h
>>>>> @@ -62,7 +62,17 @@
>>>>> /* Use ld-linux.so.3 so that it will be possible to run "classic"
>>>>> GNU/Linux binaries on an EABI system. */
>>>>> #undef GLIBC_DYNAMIC_LINKER
>>>>> -#define GLIBC_DYNAMIC_LINKER "/lib/ld-linux.so.3"
>>>>> +#define GLIBC_DYNAMIC_LINKER_SOFT_FLOAT "/lib/ld-linux.so.3"
>>>>> +#define GLIBC_DYNAMIC_LINKER_HARD_FLOAT "/lib/ld-linux-armhf.so.3"
>>>>> +#if TARGET_DEFAULT_FLOAT_ABI == ARM_FLOAT_ABI_HARD
>>>>> +#define GLIBC_DYNAMIC_LINKER_DEFAULT GLIBC_DYNAMIC_LINKER_HARD_FLOAT
>>>>> +#else
>>>>> +#define GLIBC_DYNAMIC_LINKER_DEFAULT GLIBC_DYNAMIC_LINKER_SOFT_FLOAT
>>>>> +#endif
>>>>> +#define GLIBC_DYNAMIC_LINKER \
>>>>> + "%{mfloat-abi=hard:" GLIBC_DYNAMIC_LINKER_HARD_FLOAT "} \
>>>>> + %{mfloat-abi=soft*:" GLIBC_DYNAMIC_LINKER_SOFT_FLOAT "} \
>>>>> + %{!mfloat-abi=*:" GLIBC_DYNAMIC_LINKER_DEFAULT "}"
>>>>>
>>>>> /* At this point, bpabi.h will have clobbered LINK_SPEC. We want to
>>>>> use the GNU/Linux version, not the generic BPABI version. */
>>>>
>>>> This patch is broken. Please fix this.
>>>>
>>>> You can't use a named enumeration in cpp equality.
>>>>
>>>> The type ARM_FLOAT_ABI_HARD is a named enumeration and evaluates to 0
>>>> as an unknown identifier.
>>>>
>>>> Therefore "#if TARGET_DEFAULT_FLOAT_ABI == ARM_FLOAT_ABI_HARD"
>>>> evaluates to "#if 0 == 0" and is always true.
>>>>
>>>> Watch out that "#define ARM_FLOAT_ABI_HARD ARM_FLOAT_ABI_HARD" for
>>>> such enums is not conforming C99/C11.
>>>>
>>>> I suggest you define the types as macros and then set the named enum
>>>> to those values, then use the macros in the header equality checks.
>>>>
>>>> e.g.
>>>> #define VAL1 0 then enum FOO { RVAL1 = VAL1, ... }
>>>>
>>>> Look at arm.h for the enum definition.
>>>
>>> I've looked further into this and I think the original pre-#if version
>>> is correct.
>>>
>>> The float ABI comes from these places:
>>> * The -mfloat-abi= command line argument, else
>>> * The --with-float= configure time argument, else
>>> * TARGET_DEFAULT_FLOAT_ABI from linux-eabi.h
>>>
>>> In the first case the ABI is explicit. In the second
>>> OPTION_DEFAULT_SPECS turns the configure time argument into an explict
>>> -mfloat-abi=.
>>>
>>> The patch below covers all cases, keeps the logic in the spec file,
>>> and adds a comment linking the two #defines.
>>>
>>> Tested by building with no configure flags, --wtih-float=softfp,
>>> --with-float=hard, and then running with all combinations of
>>> {,-mfloat-abi=softfp,-mfloat-abi=hard} {,-mglibc,-muclibc,-mbionic}.
>>>
>>> OK?
>>>
>>> -- Michael
>>>
>>> 2012-04-27 Michael Hope <michael.hope@linaro.org>
>>>
>>> * config/arm/linux-eabi.h (GLIBC_DYNAMIC_LINKER): Pick the loader
>>> using a spec rule.
>>>
>>
>> Michael,
>>
>> can you try this patch please. It should make it possible to then
>> create linux-eabihf.h containing just
>>
>> #undef TARGET_DEFAULT_FLOAT_ABI
>> #define TARGET_DEFAULT_FLOAT_ABI ARM_FLOAT_ABI_HARD
>> #undef GLIBC_DYNAMIC_LINKER_DEFAULT
>> #define GLIBC_DYNAMIC_LINKER_DEFAULT GLIBC_DYNAMIC_LINKER_HARD_FLOAT
>>
>> Which is not quite as simple as leaving out the second re-define, but
>> pretty close.
>
> Hi Richard. Your patch tests just fine. I like it. You could change
> the spec rule to the newer if-elseif-else form but that's a nit.
>
> -- Michael
>
Great, thanks! I've committed it as is.
R.
next prev parent reply other threads:[~2012-05-01 8:52 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-04-22 22:20 Michael Hope
2012-04-23 15:37 ` Richard Earnshaw
2012-04-23 21:37 ` Michael Hope
2012-04-24 13:32 ` Richard Earnshaw
2012-04-26 20:21 ` Carlos O'Donell
2012-04-26 23:27 ` Michael Hope
2012-04-30 15:24 ` Richard Earnshaw
2012-04-30 21:48 ` Michael Hope
2012-04-30 22:01 ` Jeff Law
2012-05-01 2:44 ` Michael Hope
2012-05-01 3:46 ` Jeff Law
2012-05-01 8:52 ` Richard Earnshaw [this message]
2012-05-23 7:13 ` Andreas Jaeger
2012-05-23 7:56 ` Richard Earnshaw
2012-05-23 8:01 ` Andreas Jaeger
2012-05-23 8:18 ` Richard Guenther
2012-05-23 14:15 ` Mike Frysinger
2012-05-23 21:12 ` Michael Hope
2012-05-24 4:08 ` Mike Frysinger
2012-05-24 8:15 ` Andrew Haley
2012-05-25 0:27 ` Mike Frysinger
2012-05-25 8:24 ` Andrew Haley
2012-05-24 17:08 ` Jakub Jelinek
2012-04-23 19:58 ` Carlos O'Donell
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=4F9FA448.6090509@arm.com \
--to=rearnsha@arm.com \
--cc=carlos@systemhalted.org \
--cc=cross-distro@lists.linaro.org \
--cc=gcc-patches@gcc.gnu.org \
--cc=libc-ports@sourceware.org \
--cc=michael.hope@linaro.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).