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llvm / lld / ee1597d5e30783fcb44456bee5f9cbcae6d3b364
commitee1597d5e30783fcb44456bee5f9cbcae6d3b364[log] [tgz]
authorTom Stellard <tstellar@redhat.com>Fri May 31 22:44:22 2019 +0000
committerTom Stellard <tstellar@redhat.com>Fri May 31 22:44:22 2019 +0000
tree045ff234e1a0fd623f0e28bff6fa81baa0546486
parentc4d6f95c15fd68f93d10ba65679677ff4cc46054 [diff]
Merging r360405:

------------------------------------------------------------------------
r360405 | maskray | 2019-05-09 22:51:00 -0700 (Thu, 09 May 2019) | 25 lines

[PPC64] Define getThunkSectionSpacing() based on the range of R_PPC64_REL24

Suggested by Sean Fertile and Peter Smith.

Thunk section spacing decrease the total number of thunks. I measured a
decrease of 1% or less in some large programs, with no perceivable
slowdown in link time. Override getThunkSectionSpacing() to enable it.
0x2000000 is the farthest point R_PPC64_REL24 can reach. I tried several
numbers and found 0x2000000 works the best. Numbers near 0x2000000 work
as well but let's just use the simpler number.

As demonstrated by the updated tests, this essentially changes placement
of most thunks to the end of the output section. We leverage this
property to fix PR40740 reported by Alfredo Dal'Ava Júnior:

The output section .init consists of input sections from several object
files (crti.o crtbegin.o crtend.o crtn.o). Sections other than the last
one do not have a terminator. With this patch, we create the thunk after
the last .init input section and thus fix the issue. This is not
foolproof but works quite well for such sections (with no terminator) in
practice.

Reviewed By: ruiu, sfertile

Differential Revision: https://reviews.llvm.org/D61720
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git-svn-id: https://llvm.org/svn/llvm-project/lld/branches/release_80@362274 91177308-0d34-0410-b5e6-96231b3b80d8
9 files changed
tree: 045ff234e1a0fd623f0e28bff6fa81baa0546486
  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.