[Patch, ARM]Enable veneer routine for R_ARM_THM_JUMP19

[Will Newton]

On 4 August 2014 10:40, Tony Wang <tony.wang@arm.com> wrote:
>> -----Original Message-----
>> From: Will Newton [mailto:will.newton@linaro.org]
>> Sent: Monday, August 04, 2014 5:14 PM
>> To: Tony Wang
>> Cc: binutils@sourceware.org; nickc@redhat.com
>> Subject: Re: [Patch, ARM]Enable veneer routine for R_ARM_THM_JUMP19
>>
>> On 4 August 2014 05:40, Tony Wang <tony.wang@arm.com> wrote:
>> > Hi there,
>> >
>> > According to AAPCS-ELF specification R_ARM_THM_JUMP19 should also be
>> > veneered if the target is outside the addressable span of the branch
>> > instruction or where interworking happened.
>> >
>> > So the attached patch implements the veneer routine for
>> > R_ARM_THM_JUMP19, and two new macros
>> THM2_MAX_FWD_COND_BRANCH_OFFSET
>> > and THM2_MAX_BWD_COND_BRANCH_OFFSET are introduced. Also
>> updated the
>> > conditional branch for both cases mentioned above.
>> >
>> > Tested with Binutils regression test, no new regressions. No
>> > regression on gcc trunk with target cortex m4
>> >
>> > Ok for the trunk?
>> >
>> > bfd/ChangeLog:
>> > 2014-08-4  Tony Wang <tony.wang@arm.com>
>> >
>> >      * elf32-arm.c (elf32_arm_final_link_relocate): Implement the
>> > veneer routine for R_ARM_THM_JUMP19.
>> >      (arm_type_of_stub): Add conditional clause for R_ARM_THM_JUMP19
>> >      (elf32_arm_size_stub): Ditto.
>> >
>> > ld/testsuite/ChangeLog:
>> > 2014-08-4  Tony Wang <tony.wang@arm.com>
>> >
>> >      * ld-arm/jump-reloc-veneers-cond.s: New test.
>> >      * ld-arm/farcall-cond-thumb-arm.s: Ditto.
>> >      * ld-arm/jump-reloc-veneers-cond-short.d: Expected output for
>> > target without a veneer generation.
>> >      * ld-arm/jump-reloc-veneers-cond-long.d: Expected output for
>> > target with a veneer generation.
>> >      * ld-arm/farcall-cond-thumb-arm.d: Expected output for inter
>> > working veneer generation.
>> >      * ld-arm/arm-elf.exp: Add tests for conditional branch veneer.
>>
>> Looks ok to me (although I am not a maintainer). Small details but logical
>> operations bind more loosely than almost every other operator so in some
>> cases you can drop the brackets around assignments in conditionals and
>> make them a bit easier to read.
>
> I agreed with your point.
>
>>Also the casts to unsigned int in
>> elf32_arm_size_stubs seem unnecessary.
>
> From my point of view, it might still needed here, as the enum type not always equals to unsigned int.

Fair enough, its not a big issue.

I also noticed a testsuite failure for armeb:

/home/will/linaro/binutils-arm/ld/../binutils/objdump -d
tmpdir/jump-reloc-veneers-cond-long
regexp_diff match failure
regexp "^    80..:      8002f040        .word   0x8002f040$"
line   "    8000:       f0408002        .word   0xf0408002"
FAIL: R_ARM_THM_JUMP19 Relocation veneers: Long

-- 
Will Newton
Toolchain Working Group, Linaro