forked from OSchip/llvm-project
b257d3c8a8
The current implementation assumes that R_PPC64_TOC16_HA is always followed by R_PPC64_TOC16_LO_DS. This can break with R_PPC64_TOC16_LO: // Load the address of the TOC entry, instead of the value stored at that address addis 3, 2, .LC0@tloc@ha # R_PPC64_TOC16_HA addi 3, 3, .LC0@tloc@l # R_PPC64_TOC16_LO blr which is used by boringssl's util/fipstools/delocate/delocate.go https://github.com/google/boringssl/blob/master/crypto/fipsmodule/FIPS.md has some documentation. In short, this tool converts an assembly file to avoid any potential relocations. The distance to an input .toc is not a constant after linking, so it cannot use an `addis;ld` pair. Instead, it jumps to a stub which loads the TOC entry address with `addis;addi`. This patch checks the presence of R_PPC64_TOC16_LO and suppresses toc-indirect to toc-relative relaxation if R_PPC64_TOC16_LO is seen. This approach is conservative and loses some relaxation opportunities but is easy to implement. addis 3, 2, .LC0@toc@ha # no relaxation addi 3, 3, .LC0@toc@l # no relaxation li 9, 0 addis 4, 2, .LC0@toc@ha # can relax but suppressed ld 4, .LC0@toc@l(4) # can relax but suppressed Also note that interleaved R_PPC64_TOC16_HA and R_PPC64_TOC16_LO_DS is possible and this patch accounts for that. addis 3, 2, .LC1@toc@ha # can relax addis 4, 2, .LC2@toc@ha # can relax ld 3, .LC1@toc@l(3) # can relax ld 4, .LC2@toc@l(4) # can relax Reviewed By: #powerpc, sfertile Differential Revision: https://reviews.llvm.org/D78431 |
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| .. | ||
| COFF | ||
| Common | ||
| ELF | ||
| MachO | ||
| MinGW | ||
| cmake/modules | ||
| docs | ||
| include/lld | ||
| lib | ||
| test | ||
| tools/lld | ||
| unittests | ||
| utils | ||
| wasm | ||
| .clang-format | ||
| .clang-tidy | ||
| .gitignore | ||
| CMakeLists.txt | ||
| CODE_OWNERS.TXT | ||
| LICENSE.TXT | ||
| README.md | ||
README.md
LLVM Linker (lld)
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.
lld is open source software. You may freely distribute it under the terms of the license agreement found in LICENSE.txt.
Benchmarking
In order to make sure various developers can evaluate patches over the same tests, we create a collection of self contained programs.
It is hosted at https://s3-us-west-2.amazonaws.com/linker-tests/lld-speed-test.tar.xz
The current sha256 is 10eec685463d5a8bbf08d77f4ca96282161d396c65bd97dc99dbde644a31610f.