[ELF] Reject certain unknown section types (#85173)

Unknown section sections may require special linking rules, and
rejecting such sections for older linkers may be desired. For example,
if we introduce a new section type to replace a control structure (e.g.
relocations), it would be nice for older linkers to reject the new
section type. GNU ld allows certain unknown section types:

* [SHT_LOUSER,SHT_HIUSER] and non-SHF_ALLOC
* [SHT_LOOS,SHT_HIOS] and non-SHF_OS_NONCONFORMING

but reports errors and stops linking for others (unless
--no-warn-mismatch is specified). Port its behavior. For convenience, we
additionally allow all [SHT_LOPROC,SHT_HIPROC] types so that we don't
have to hard code all known types for each processor.

Close https://github.com/llvm/llvm-project/issues/84812

GitOrigin-RevId: e115c00565be88677e8b7fe021a3e242249c67b8
8 files changed
tree: 89864439f5439af9ae8a513202a6395ea9d9be89
  1. cmake/
  2. COFF/
  3. Common/
  4. docs/
  5. ELF/
  6. include/
  7. MachO/
  8. MinGW/
  9. test/
  10. tools/
  11. unittests/
  12. utils/
  13. wasm/
  14. .clang-format
  15. .clang-tidy
  16. .gitignore
  17. CMakeLists.txt
  18. CODE_OWNERS.TXT
  19. LICENSE.TXT
  20. 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.