Re: [PATCH]Replace -shared with -r -nostdlib in gcc.dg/lto/pr61526 pr54709 pr64415 test cases.

[Richard Biener <richard dot guenther at gmail dot com>]

On Tue, Mar 1, 2016 at 4:56 PM, Renlin Li <renlin.li@foss.arm.com> wrote:
> Hi Richard,
>
>
> On 01/03/16 09:16, Richard Biener wrote:
>>
>> On Mon, Feb 29, 2016 at 5:13 PM, Renlin Li <renlin.li@foss.arm.com> wrote:
>>>
>>> Hi all,
>>>
>>> The gcc.dg/lto/pr54709, pr61526, pr64415 linking testcases keep failing
>>> on
>>> arm/aarch64 bare-metal target.
>>>
>>> It's because statically built newlib library is used to link with shared
>>> object.
>>> And the linker complains about relocations which cannot be used in
>>> shared object.
>>>
>>> For example, the following errors are produced:
>>>
>>> crtbegin.o: relocation R_ARM_MOVW_ABS_NC against `a local symbol' can not
>>> be
>>> used when making a shared object; recompile with -fPIC
>>>
>>> crtbegin.o: relocation R_ARM_THM_MOVW_ABS_NC against `a local symbol' can
>>> not
>>> be used when making a shared object; recompile with -fPIC
>>>
>>> librdimon.a(rdimon-syscalls.o): relocation R_AARCH64_ADR_PREL_PG_HI21
>>> against
>>> external symbol `_impure_ptr' can not be used when making a shared
>>> object;
>>> recompile with -fPIC
>>>
>>> Presumably, bare-metal toolchain for other architecture have those test
>>> case
>>> failures as well?
>>>
>>> In this patch, -shared option is replace by -r -nostdlib. So that the
>>> standard
>>> system startup files or libraries are not used when linking.
>>
>> Note that -shared is not equivalent to -r -nostdlib so please verify that
>> the
>> original issue can be still reproduced with its fix reverted but -r
>> -nostdlib
>> used with the new -r -nostdlib handling on trunk.
>
>
> pr54709_0.c: Cannot be reproduced with even -shared. The error message is
> the same as shown above.
> pr64415_0.c: Reproduced with "-r -nostdlib".
> pr61526_0.c: Reproduced with "-r -nostdlib".
>
> By the way, those linking test cases all pass for linux toolchain. Only fail
> for aarch64/arm baremetal toolchain.
>
> Andrew, I saw you have done similar things in r153555
> https://gcc.gnu.org/viewcvs/gcc?view=revision&revision=153555
>
> Do you have any thoughts?
>
> And also here, the last comments in this ticket suggests to add
> check_effective_target_shared to the exp file to limit it to linux targets
> only:
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61526

As said LTO testcases tend to be somewhat fragile so limiting them to
targets known to work might be the best option.

Richard.

> Regards,
> Renlin
>
>
>>
>> Otherwise simply dg-skip for aarch64.
>>
>> Richard.
>>
>>> arm-none-eabi, aarch64-none-elf regression test OK, OK for trunk?
>>>
>>> Regards,
>>> Renlin Li
>>>
>>> gcc/testsuite/ChangeLog:
>>>
>>> 2016-02-29  Renlin Li<renlin.li@arm.com>
>>>
>>>          * gcc.dg/lto/pr54709_0.c: Replace -shard with -r -nostdlib.
>>>          * gcc.dg/lto/pr61526_0.c: Ditto.
>>>          * gcc.dg/lto/pr64415_0.c: Ditto.
>>>
>