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PowerPC64 --plt-align
- From: Alan Modra <amodra at gmail dot com>
- To: Binutils Development <binutils at sourceware dot org>
- Date: Wed, 13 Sep 2017 17:25:17 +0930
- Subject: PowerPC64 --plt-align
- Authentication-results: sourceware.org; auth=none
Resent after losing emails I tried to send while in Prague.
git commit 2420fff633 for the patch
git commit 38d47c224 on 2.29 branch
This changes the PowerPC64 --plt-align option to perform the usual
alignment of code as suggested by its name, as well as the previous
behaviour of padding so as to reduce boundary crossing. The old
behaviour is had by using a negative parameter.
The default is also changed to align plt stub code by default to 32
byte boundaries, the point being to get better bctr branch prediction
on power8 and power9 hardware.
bfd/
* elf64-ppp.c (plt_stub_pad): Handle positive and negative
plt_stub_align.
ld/
* ld.texinfo (--plt-align): Describe new behaviour of option.
* emultempl/ppc64elf.em (params): Default plt_stub_align to 5.
* testsuite/ld-powerpc/powerpc.exp: Pass --no-plt-align for
selected tests.
* testsuite/ld-powerpc/relbrlt.d: Pass --no-plt-align.
* testsuite/ld-powerpc/elfv2so.d: Adjust expected output.