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mold 1.8.0
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@rui314 rui314 released this 26 Dec 07:10
· 1249 commits to main since this release
v1.8.0
a49a201

mold 1.8.0 is a new release of the high-speed linker.

New features

  • The --relocatable (or -r) option has been reimplemented to improve its performance and compatibility with the GNU linkers. That option tells the linker to combine input object files into another object file instead of into an executable or a shared library file. mold has been supporting the feature since version 0.9, but until now the output file created with -r looked fairly different from what GNU linkers would produce. GHC (Glasgow Haskell Compiler) in particular uses re-linkable object files as dynamic libraries instead of real .so files, and it didn't work with mold. Now, mold can produce object files that GHC can load. Note that this work was funded by Mercury, so thanks to the company to help us improve the product. (Yes, you can ask us to prioritize your feature request by funding the project.) (c9a7ae7)
  • --relocatable-merge-sections option has been added. By default, mold keeps original input section names for the --relocatable output and therefore does not merge input sections into a single output sections unless they are of the same name. If --relocatable-merge-sections is given, mold merges input by the usual default merging rule. For example, .text.foo and .text.bar are merged to .text if and only if --relocatable-merge-sections is given for the --relocatable output. (c2a0ae1)
  • -z [no]dynamic-undefined-weak options have been added. This option controls whether an undefined weak symbol is promoted to a dynamic symbol or not. (ed235f3)
  • --[no-]undefined-version options have been supported. Now, mold warns on a symbol name in a version script if it does not match with any defined symbol. This change was made so that it is easy to find a typo in a version script. (e2d7353)
  • mold now warns on symbol type mismatch. If two object files have the same symbol with different symbol types, it usually means your program has a bug. Chances are, you are using the same identifier as a function name in one translation unit and as a global variable name in another. So it makes sense to warn on the mismatch. (b70211e)
  • mold now merges .gnu.note.property sections for various x86 properties. (d30d743)

Removed features

  • The experimental macOS/iOS support has been removed from mold. If you want to use it, please use our sold linker instead.

Bug fixes and compatibility improvements

  • --wrap now works with LTO. (07d8911)
  • A global variable initialized with an IFUNC function pointer is now initialized correctly with the function's address. Previously, it was mistakenly initialized to the function resolver's address. (b2858d2)
  • The filename specified by --version-script or --dynamic-list is now searched from library search paths if it does not exist in the current working directory. This behavior is compatible with GNU linkers. (3c1a055, 8c87f16)
  • mold now tries to avoid creating copy relocations as much as possible. This change fixed a compatibility issue with GHC. (5866c9e)
  • Thread-local variables are now correctly aligned even if there's a TLV with a large alignment. (bd46edf)
  • mold can now handle GCC LTO files created with -ffat-lto-objects. (804b843)
  • mold now accepts -z nopack-relative-relocs as an alias for --pack-dyn-relocs=none for the sake of compatibility with GNU linkers. (b510588)
  • mold now recognizes -z start-stop-visibility=hidden but ignores it because it's the default for mold. GNU linkers support this option to control the visibility of linker-synthesized __start_<sectname> and __stop_<sectname> symbols, with global as the default visibility. mold creates these symbols with the hidden visibility by default, which is desirable for almost all cases. (22c9ec8)
  • [ARM32, i386] mold now emits REL-type relocations instead of RELA-type for the --relocatable output file. (8b373d3)

Acknowledgements

mold is an open-source project, and we accept donations via GitHub Sponsors and OpenCollective. We thank you to everybody who sponsors our project. In particular, we'd like to acknowledge the following organizations and people who have sponsored $32/mo or more during this release cycle:

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