[all-commits] [llvm/llvm-project] e364b9: [libc++] Take the mersenne twister ABI break uncon...

[Nikolas Klauser via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: e364b9da263dcd9a4dcda0d183f403d3f138bb51
      https://github.com/llvm/llvm-project/commit/e364b9da263dcd9a4dcda0d183f403d3f138bb51
  Author: Nikolas Klauser <nikolasklauser at berlin.de>
  Date:   2026-09-16 (Wed, 16 Sep 2026)

  Changed paths:
    M libcxx/include/__configuration/abi.h
    M libcxx/include/__random/mersenne_twister_engine.h
    M libcxx/test/std/numerics/rand/rand.eng/rand.eng.mers/ctor_result_type.pass.cpp
    M libcxx/test/std/numerics/rand/rand.eng/rand.eng.mers/ctor_sseq.pass.cpp
    M libcxx/utils/libcxx/test/features/libcxx_macros.py

  Log Message:
  -----------
  [libc++] Take the mersenne twister ABI break unconditionally (#222700)

Technically this is ABI breaking, since we change the meaning of the
bytes inside the mersenne twister. However, this doesn't cause changes
in the size of any objects and is only an issue in very specific
circumstances. Specifically, the mersenne twister has to be passed on an
ABI boundary and be used on both sides of that ABI boundary. If it's
only used on one side, the values will continue to be correct, since
only a single algorithm is used. Even then, the only issue is that the
values aren't properly randomized, since both versions of the mersenne
twister implementation read the same type of data and produce the same
kind of output with it.

Fixes #209514



To unsubscribe from these emails, change your notification settings at https://github.com/llvm/llvm-project/settings/notifications