commit | cf47f8dd15d304b822130957d16a5dd058485339 | [log] [tgz] |
---|---|---|
author | Nico Weber <nicolasweber@gmx.de> | Wed Jan 30 02:17:27 2019 +0000 |
committer | Nico Weber <nicolasweber@gmx.de> | Wed Jan 30 02:17:27 2019 +0000 |
tree | 6bffc513df82e258ae684593b12a274f2e5b8241 | |
parent | 25db38eac5ffec9ff7f24757c7daf43d885e7e35 [diff] |
lld/coff: Implement some support for the comdat selection field LLD used to handle comdats as if the selection field was always set to IMAGE_COMDAT_SELECT_ANY. This means for obj files produced by `cl /Gy`, LLD would never report a duplicate symbol error. This change: - adds validation for the Selection field (should make no difference in practice for compiler-generated obj inputs) - rejects comdats that have different Selection fields in different obj files (likewise). This is a bit more strict but also more self-consistent thank link.exe (see comment in code) - implements handling for all the selection kinds In practice, compilers only generate comdats with IMAGE_COMDAT_SELECT_NODUPLICATES (LLD now produces duplicate symbol errors for these), IMAGE_COMDAT_SELECT_ANY (no behavior change), and IMAGE_COMDAT_SELECT_LARGEST (for RTTI data; here LLD should no longer create broken executables when linking some TUs with RTTI enabled and some with it disabled – but see below). The implementation of `IMAGE_COMDAT_SELECT_LARGEST` is incomplete: If one SELECT_LARGEST comdat replaces an earlier one, the comdat symbol is replaced correctly, but the old section stays loaded and if /opt:ref is disabled (via /opt:noref or /debug) it's still written to the output. That's not ideal, but better than the current treatment of just picking any one of those comdats. I hope to fix this better later. Fixes most of PR40094. Differential Revision: https://reviews.llvm.org/D57324 git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@352590 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.
lld is open source software. You may freely distribute it under the terms of the license agreement found in LICENSE.txt.
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
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