On 27/04/12 00:27, Michael Hope wrote:
> On 27 April 2012 08:20, Carlos O'Donell <car...@systemhalted.org> wrote:
>> On Mon, Apr 23, 2012 at 5:36 PM, Michael Hope <michael.h...@linaro.org>
>> wrote:
>>> 2012-04-24 Michael Hope <michael.h...@linaro.org>
>>> Richard Earnshaw <rearn...@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.h...@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.
R.
--- linux-eabi.h (revision 186924)
+++ linux-eabi.h (local)
@@ -32,7 +32,8 @@
while (false)
/* We default to a soft-float ABI so that binaries can run on all
- target hardware. */
+ target hardware. If you override this to use the hard-float ABI then
+ change the setting of GLIBC_DYNAMIC_LINKER_DEFAULT as well. */
#undef TARGET_DEFAULT_FLOAT_ABI
#define TARGET_DEFAULT_FLOAT_ABI ARM_FLOAT_ABI_SOFT
@@ -59,16 +60,19 @@
#undef SUBTARGET_EXTRA_LINK_SPEC
#define SUBTARGET_EXTRA_LINK_SPEC " -m " TARGET_LINKER_EMULATION
-/* Use ld-linux.so.3 so that it will be possible to run "classic"
- GNU/Linux binaries on an EABI system. */
+/* GNU/Linux on ARM currently supports three dynamic linkers:
+ - ld-linux.so.2 - for the legacy ABI
+ - ld-linux.so.3 - for the EABI-derived soft-float ABI
+ - ld-linux-armhf.so.3 - for the EABI-derived hard-float ABI.
+ All the dynamic linkers live in /lib.
+ We default to soft-float, but this can be overridden by changing both
+ GLIBC_DYNAMIC_LINKER_DEFAULT and TARGET_DEFAULT_FLOAT_ABI. */
+
#undef GLIBC_DYNAMIC_LINKER
#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 "} \
