[FFmpeg-devel] [PATCH] swresample/arm: avoid conditional branch to PLT in THUMB-2.

Michael Niedermayer michael at niedermayer.cc
Tue Apr 17 16:17:30 EEST 2018

On Mon, Apr 16, 2018 at 01:13:21PM -0700, Rahul Chaudhry wrote:
> Hi Michael,
> While it is true that some linkers support the conditional branch to PLT in
> Thumb mode, it is of very limited use, since it uses an R_ARM_THM_JUMP19
> relocation and does not have a good range. If I switch my linker to ld.bfd for
> the original issue, it fails for another library with a "relocation truncated
> to fit" error message because the PLT entry is out of range of the conditional
> branch and cannot be handled by the R_ARM_THM_JUMP19 relocation.
> It is cleaner and more stable (for all linkers) to convert the conditional
> branch to an unconditional one which uses an R_ARM_THM_JUMP24 relocation and
> has a range of 16MB.

why does it go through the PLT at all ?


Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

No snowflake in an avalanche ever feels responsible. -- Voltaire
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