Re: Problem with ARM longcalls

[Richard Guenther <richard.guenther@gmail.com>]

On Thu, Apr 14, 2011 at 2:40 PM, Bernd Schmidt <bernds@codesourcery.com> wrote:
> Ping.  Contains only changes outside config/arm.
>
> http://gcc.gnu.org/m/gcc-patches/2011-03/msg01509.html

Ok.

Thanks,
Richard.

>
> Bernd
>
> On 03/23/2011 04:46 PM, Bernd Schmidt wrote:
>> I've discovered a problem with -mlong-calls on ARM. The bug was first
>> reported against a new target, but I'd copied the relevant code from the
>> ARM backend.
>>
>> We use current_function_section in arm_is_long_call_p to decide whether
>> we're calling something that goes into the same section. The problem
>> with this is that current_function_section can only be used during
>> final, since it relies on the global variable in_cold_section_p which is
>> set up only in assemble_start_function. On ARM, this problem manifests
>> as short-calls when a long-call would be required; in the other port it
>> was an "insn doesn't satisfy its constraints" error.
>>
>> The following patch is against 4.5, since the problem appears hidden in
>> mainline (the initialization of first_function_block_is_cold has
>> changed). Ok for trunk and branches after arm-linux tests complete?
>
>>       * function.c (init_function_start): Call decide_function_section.
>>       * varasm.c (decide_function_section): New function.
>>       (assemble_start_function): When not using
>>       flag_reorder_blocks_and_partition, don't compute in_cold_section_p
>>       or first_function_block_is_cold.
>>       * rtl.h (decide_function_section): Declare.
>>
>>       * gcc.target/arm/cold-lc.c: New test.
>