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llvm / lld / 833d8cf473b2c1e1981f8d3012cd176abced9ad2
commit833d8cf473b2c1e1981f8d3012cd176abced9ad2[log] [tgz]
authorFangrui Song <maskray@google.com>Wed Nov 21 18:10:00 2018 +0000
committerFangrui Song <maskray@google.com>Wed Nov 21 18:10:00 2018 +0000
tree74381721cd3fc28c47dc4173a48c50a25686c482
parent3ad31c539fe257ebe9d9c6c2df71fb6f905533b9 [diff]
[ELF] Write IPLT header in -static -z retpolineplt mode

Summary:
This fixes PR39711: -static -z retpolineplt does not produce retpoline PLT header.
-z now is not relevant.

Statically linked executable does not have PLT, but may have IPLT with no header. When -z retpolineplt is specified, however, the repoline PLT header should still be emitted.

I've checked that this fixes the FreeBSD reproduce in PR39711 and a Linux program statically linked against glibc. The programm print "Hi" rather than SIGILL/SIGSEGV.

getPltEntryOffset may look dirty after this patch, but it can be cleaned up later.

Another possible improvement is that when there are non-preemptible IFUNC symbols (rare case, e.g. -Bsymbolic), both In.Plt and In.Iplt can be non-empty and we'll emit the retpoline PLT header twice.

Reviewers: espindola, emaste, chandlerc, ruiu

Reviewed By: emaste

Subscribers: emaste, arichardson, krytarowski, llvm-commits

Differential Revision: https://reviews.llvm.org/D54782

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@347404 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed
tree: 74381721cd3fc28c47dc4173a48c50a25686c482
  1. cmake/
  2. COFF/
  3. Common/
  4. docs/
  5. ELF/
  6. include/
  7. lib/
  8. MinGW/
  9. test/
  10. tools/
  11. unittests/
  12. utils/
  13. wasm/
  14. .arcconfig
  15. .clang-format
  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.