14e3bec8fc
This patch adds support to lld for --fat-lto-objects. We add a new --fat-lto-objects option to LLD, and slightly change how it chooses input files in the driver when the option is set. Fat LTO objects contain both LTO compatible IR, as well as generated object code. This allows users to defer the choice of whether to use LTO or not to link-time. This is a feature available in GCC for some time, and makes the existing -ffat-lto-objects option functional in the same way as GCC's. If the --fat-lto-objects option is passed to LLD and the input files are fat object files, then the linker will chose the LTO compatible bitcode sections embedded within the fat object and link them together using LTO. Otherwise, standard object file linking is done using the assembly section in the object files. The previous version of this patch had a missing `REQUIRES: x86` line in `fatlto.invalid.s`. Additionally, it was reported that this patch caused a test failure in `export-dynamic-symbols.s`, however, 29112a994694baee070a2021e00f772f1913d214 disabled the `export-dynamic-symbols.s` test on Windows due to a quotation difference between platforms, unrelated to this patch. Original RFC: https://discourse.llvm.org/t/rfc-ffat-lto-objects-support/63977 Reviewed By: MaskRay Differential Revision: https://reviews.llvm.org/D146778
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.