bytecodealliance/wasmtime v34.0.0

on GitHub

34.0.0

Released 2025-06-20.

Added

• Support for SIMD in the Pulley interpreter can now be disabled at compile-time
  to shrink the size of the final binary.
  #10727

• The C API now has wasmtime_trap_new_code to create a wasm_trap_t from
  its code.
  #10765

• Winch's support for x86_64 is now classified with tier 1 support in Wasmtime.
  #10755

• Winch's support for aarch64 now implements stack checks to pass many more spec
  tests.
  #10763

• Cranelift's s390x backend now has full support for the f128 type.
  #10774

• Wasmtime's C API for the component model has initial support for calling
  functions.
  #10697
  #10841
  #10858
  #10864
  #10877

• The wasmtime wast command now has a --generate-dwarf flag to show
  filename/line number information for backtraces.
  #10780

Changed

• The shape of bindgen!-generated add_to_linker functions has changed with
  the removal of GetHost and replacement of a HasData trait. For more
  information see the associated PR.
  #10770

• Wasmtime's Store<T> now requires that T: 'static. This is done in
  preparation for merging WASIp3 work to the main repository with some more
  information on the associated PR.
  #10760

• The wasmtime::component::Instance::instance_pre method is now public.
  #10761

• Wasmtime and Cranelift's minimnum supported version of Rust (MSRV) is now
  1.85.0.
  #10785

• Cranelift's debugtrap on aarch64 now generates brk #0xf000 for debuggers
  to recognize it.
  #10813

• The wasi-http implementation no longer generates a trap if the handle to
  receive the response on the host is dropped early.
  #10833

• The wasmtime serve command will now send some boilerplate descriptive HTML
  on a 500 server error instead of nothing.
  #10851

• A significant amount of work has gone into the new assembler for the x64
  backend. Too many PRs to list here but progress continues apace at defining
  all machine instructions in a standalone crate.

• Cranelift will now reject unimplemented big-endian loads/stores on backends
  that do not implement this functionality.
  #10863

• The wasmtime explore generated HTML handles large modules better now.
  #10892

• Wasmtime's internal representation of wasmtime::Func has changed and a
  previous optimization of Func::call has been lost. If affected it'd
  recommended to use Func::call_unchecked instead or to open an issue.
  #10897