| commit | 40fecdb5f8ce59dfd3a7db89bd6509f68a6d69a6 | [log] [tgz] |
|---|---|---|
| author | Fangrui Song <maskray@google.com> | Tue May 07 04:26:05 2019 +0000 |
| committer | Fangrui Song <maskray@google.com> | Tue May 07 04:26:05 2019 +0000 |
| tree | f2db44936d5426673e048c532c952895cdea3a80 | |
| parent | 7f93e61036319b59ef44d0eab65eb1894c61c3e9 [diff] |
[PPC64] toc-indirect to toc-relative relaxation
This is based on D54720 by Sean Fertile.
When accessing a global symbol which is not defined in the translation unit,
compilers will generate instructions that load the address from the toc entry.
If the symbol is defined, non-preemptable, and addressable with a 32-bit
signed offset from the toc pointer, the address can be computed
directly. e.g.
addis 3, 2, .LC0@toc@ha # R_PPC64_TOC16_HA
ld 3, .LC0@toc@l(3) # R_PPC64_TOC16_LO_DS, load the address from a .toc entry
ld/lwa 3, 0(3) # load the value from the address
.section .toc,"aw",@progbits
.LC0: .tc var[TC],var
can be relaxed to
addis 3,2,var@toc@ha # this may be relaxed to a nop,
addi 3,3,var@toc@l # then this becomes addi 3,2,var@toc
ld/lwa 3, 0(3) # load the value from the address
We can delete the test ppc64-got-indirect.s as its purpose is covered by
newly added ppc64-toc-relax.s and ppc64-toc-relax-constants.s
Reviewed By: ruiu, sfertile
Differential Revision: https://reviews.llvm.org/D60958
git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@360112 91177308-0d34-0410-b5e6-96231b3b80d8
This directory and its subdirectories contain source code for the LLVM Linker, a modular cross platform linker which is built as part of the LLVM compiler infrastructure project.
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In order to make sure various developers can evaluate patches over the same tests, we create a collection of self contained programs.
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