mold 2.35.0 is a new release of the high-speed linker. It includes the following new features and bug fixes.

New features

• Big-endian ARM64 is now supported. ARM64 is a bi-endian processor, meaning that the processor can run in either little- or big-endian mode. Even though little-endian is the de facto standard, the ARM64 processor-specific ABI defines its big-endian variant, and the ARM toolchain supports it. Now we support it too. (882e7eb)
• Big-endian SH4 is now supported. SH4 has become a minor CPU nowadays, and its big-endian variant is even more so, but some SHARP scientific calculators still use SH4 processors in big-endian mode. (0cb9fc6)

Bug fixes and compatibility improvements

• mold attempts to overwrite an existing file if a specified output file already exists because reusing an existing file is much faster than creating a fresh file and writing to it on Linux. If an existing file is currently running, open(2) for that file fails with ETXTBSY. When that happens, mold falls back to creating a new file. The problem here is that Linux kernel version 6.11 changed that well-known behavior of open(2), and it now allows user programs to overwrite a running executable. That caused a very mysterious issue for programs that rebuild themselves during the build, such as gcc or ninja (#1361). Even though the kernel's change has been reverted (torvalds/linux@3b83203), we need to make adjustments to mold for that particular version of the Linux kernel. So, if mold detects that it is running on Linux 6.11, it no longer tries to reuse an existing output file. (8e4f7b5)
• On rare occasions, mold could fail with a "ConcurrentMap is full" error. Now the issue has been resolved. (e56b649)
• Even if a user choose not to use mimalloc memory allocator (i.e. built mold with -DMOLD_USE_MIMALLOC=0), mold was still being built with mimalloc. This issue has been resolved. (ffd10dd)
• [s390x] s390x uses nonstandard 8-byte entries for the .hash section. Previously, mold created 4-byte entries for .hash, which caused mold-generated executables to crash on startup if they were built with -Wl,--hash-style=sysv. Now, mold generates a psABI-compliant .hash section. (e2e1146)

Acknowledgements

mold is an open-source project, and we accept donations via GitHub Sponsors and OpenCollective. We thank everyone 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:

• Ahrefs
• VMind AI
• Cybozu, Inc.
• Signal Slot Inc.
• Bryant Biggs
• kraptor23
• Mercury
• G-Research-OSS
• Jinkyu Yi
• David Wells
• Ville Vesilehto
• Mercedes-Benz Group
• CubeSoft, Inc.
• superfunc
• Miguel I. Solano
• Wei Wu
• daquexian
• Josh Triplett
• nomeaning
• Igor Matuszewski
• Rahul Butani
• Kyle Lacy
• Martin Liška
• Foxie Solutions