microsoft/snmalloc 0.7.2

0.7.2

Repository: microsoft/snmalloc

Tag: 0.7.2

Published: 2025-08-05T10:30:38Z

Prerelease: no

Release notes:

What's Changed

Secondary Allocator

Thanks to @SchrodingerZhu for allowing snmalloc to support a secondary allocator, such as GWP-Asan. This feature allows snmalloc to pass some allocation and their corresponding deallocation to another allocator. This can be used for a GWP-Asan integration, and will be used to enable detours on Windows to override the default allocator.

• Enable a secondary allocator support (e.g. GWP-Asan) by @SchrodingerZhu in https://github.com/microsoft/snmalloc/pull/737
• Fix test when using GWP-Asan by @mjp41 in https://github.com/microsoft/snmalloc/pull/758
• Make Secondary Allocator a template parameter by @mjp41 in https://github.com/microsoft/snmalloc/pull/774

The next major release will build more on this feature.

Platforms

Windows support

Thanks to @NeilMonday for the Windows support improvements in particular the ability to unload snmalloc without leaking the memory associated with snmalloc.

• Windows: Remove exception handler for pagemap on unloading by @NeilMonday in https://github.com/microsoft/snmalloc/pull/746
• Release all reservations at the very end of the program or DLL by @NeilMonday in https://github.com/microsoft/snmalloc/pull/773

Rust

• [Rust] add support for optionally compiling libc functions by @wpbrown in https://github.com/microsoft/snmalloc/pull/763

Libc support

• Protection against fork by @mjp41 in https://github.com/microsoft/snmalloc/pull/735
• Update realloc(p,0) semantics. by @mjp41 in https://github.com/microsoft/snmalloc/pull/753
• Prevent internal errno setting escaping to the client. by @mjp41 in https://github.com/microsoft/snmalloc/pull/754

C++ support

• Add exception handling for new operator by @mjp41 in https://github.com/microsoft/snmalloc/pull/791

CI and build

• Mistaken commit of message_once by @mjp41 in https://github.com/microsoft/snmalloc/pull/741
• cmake: Fix HAS_EXCEPTION on Windows. by @mjp41 in https://github.com/microsoft/snmalloc/pull/743
• CI: Refresh Targets by @mjp41 in https://github.com/microsoft/snmalloc/pull/748
• build: Fix nothrow include. by @mjp41 in https://github.com/microsoft/snmalloc/pull/749
• CI: Cancel inflight checks on a new push. by @mjp41 in https://github.com/microsoft/snmalloc/pull/760
• Header-only build fix for WIN32_LEAN_AND_MEAN redefinition by @sooknarine in https://github.com/microsoft/snmalloc/pull/764
• Remove 20.04 from CI by @mjp41 in https://github.com/microsoft/snmalloc/pull/768
• Drop Win2019 from CI by @mjp41 in https://github.com/microsoft/snmalloc/pull/778
• Update minimum CMake version https://github.com/microsoft/snmalloc/pull/793

Bazel

Thanks to @jayakasadev for adding Bazel support to snmallocs build.

• feat: add support for bazel by @jayakasadev in https://github.com/microsoft/snmalloc/pull/759
• Add build platform and type to Bazel cache key by @mjp41 in https://github.com/microsoft/snmalloc/pull/779

Refactor and minor bugs fixes

• Refactor: Remove unused features and functions, and move most allocator operations to a global namespace. by @mjp41 in https://github.com/microsoft/snmalloc/pull/750
• Bug fixes by @mjp41 in https://github.com/microsoft/snmalloc/pull/752
• Fixed pagemap reservations for a fixed-region use-case using the default PAL by @Trithek in https://github.com/microsoft/snmalloc/pull/757
• Refactor check_bounds by @mjp41 in https://github.com/microsoft/snmalloc/pull/756
• Refactor representation of thread local state. by @mjp41 in https://github.com/microsoft/snmalloc/pull/751
• Fix bug in pool sort by @mjp41 in https://github.com/microsoft/snmalloc/pull/765
• Reentrancy init by @mjp41 in https://github.com/microsoft/snmalloc/pull/767
• Fix CI by @mjp41 in https://github.com/microsoft/snmalloc/pull/776
• Remove tests for experimental jemalloc ABIs by @markjdb in https://github.com/microsoft/snmalloc/pull/770
• Adjust func-memory test to be shorter. by @mjp41 in https://github.com/microsoft/snmalloc/pull/780
• Improve sizeclass calculation by @mjp41 in https://github.com/microsoft/snmalloc/pull/777
• Pass continuations for success and failure cases by @mjp41 in https://github.com/microsoft/snmalloc/pull/788
• Fallible notify using by @mjp41 in https://github.com/microsoft/snmalloc/pull/790
• Code Quality - inlining and reduce PreventFork usage by @mjp41 in https://github.com/microsoft/snmalloc/pull/792

New Contributors

• @Trithek made their first contribution in https://github.com/microsoft/snmalloc/pull/757
• @sooknarine made their first contribution in https://github.com/microsoft/snmalloc/pull/764
• @wpbrown made their first contribution in https://github.com/microsoft/snmalloc/pull/763
• @jayakasadev made their first contribution in https://github.com/microsoft/snmalloc/pull/759
• @markjdb made their first contribution in https://github.com/microsoft/snmalloc/pull/770

Full Changelog: https://github.com/microsoft/snmalloc/compare/0.7.1...0.7.2