Released 2023-09-20
Added
* Configuration of mach ports vs signals on macOS is now done through a `Config`
instead of at compile time.
[6807](https://github.com/bytecodealliance/wasmtime/pull/6807)
* `Engine::detect_precompiled{,_file}` can be used to determine whether some
bytes or a file look like a precompiled module or a component.
[6832](https://github.com/bytecodealliance/wasmtime/pull/6832)
[6937](https://github.com/bytecodealliance/wasmtime/pull/6937)
* A new feature "wmemcheck" has been added to enable Valgrind-like detection of
use-after-free within a WebAssembly guest module.
[6820](https://github.com/bytecodealliance/wasmtime/pull/6820)
[6856](https://github.com/bytecodealliance/wasmtime/pull/6856)
* The `wasmtime` CLI now supports executing components.
[6836](https://github.com/bytecodealliance/wasmtime/pull/6836)
* Support for WASI preview2's TCP sockets interface has been added.
[6837](https://github.com/bytecodealliance/wasmtime/pull/6837)
* Wasmtime's implementation of the wasi-nn proposal now supports named models.
[6854](https://github.com/bytecodealliance/wasmtime/pull/6854)
* The C API now supports configuring `native_unwind_info`,
`dynamic_memory_reserved_for_growth`, `target`, and Cranelift settings.
[6896](https://github.com/bytecodealliance/wasmtime/pull/6896)
[6934](https://github.com/bytecodealliance/wasmtime/pull/6934)
* The `wasmtime` crate now has initial support for component model bindings
generation for the WIT `resource` type.
[6886](https://github.com/bytecodealliance/wasmtime/pull/6886)
* Cranelift's RISC-V backend now has a complete implementation of the
WebAssembly SIMD proposal. Many thanks to Afonso Bordado for all their
contributions!
[6920](https://github.com/bytecodealliance/wasmtime/pull/6920)
[6924](https://github.com/bytecodealliance/wasmtime/pull/6924)
* The `bindgen!` macro in the `wasmtime` crate now supports conditional
configuration for which imports should be `async` and which should be
synchronous.
[6942](https://github.com/bytecodealliance/wasmtime/pull/6942)
Changed
* The pooling allocator was significantly refactored and the
`PoolingAllocationConfig` has some minor breaking API changes that reflect
those changes.
Previously, the pooling allocator had `count` slots, and each slot had `N`
memories and `M` tables. Every allocated instance would reserve those `N`
memories and `M` tables regardless whether it actually needed them all or
not. This could lead to some waste and over-allocation when a module used less
memories and tables than the pooling allocator's configured maximums.
After the refactors in this release, the pooling allocator doesn't have
one-size-fits-all slots anymore. Instead, memories and tables are in separate
pools that can be allocated from independently, and we allocate exactly as
many memories and tables as are necessary for the instance being allocated.
To preserve your old configuration with the new methods you can do the following:
rust
let mut config = PoolingAllocationConfig::default();
// If you used to have this old, no-longer-compiling configuration:
config.count(count);
config.instance_memories(n);
config.instance_tables(m);
// You can use these equivalent settings for the new config methods:
config.total_core_instances(count);
config.total_stacks(count); // If using the `async` feature.
config.total_memories(count * n);
config.max_memories_per_module(n);
config.total_tables(count * m);
config.max_tables_per_module(m);
There are additionally a variety of methods to limit the maximum amount of
resources a single core Wasm or component instance can take from the pool:
* `PoolingAllocationConfig::max_memories_per_module`
* `PoolingAllocationConfig::max_tables_per_module`
* `PoolingAllocationConfig::max_memories_per_component`
* `PoolingAllocationConfig::max_tables_per_component`
* `PoolingAllocationConfig::max_core_instances_per_component`
These methods do not affect the size of the pre-allocated pool.
[6835](https://github.com/bytecodealliance/wasmtime/pull/6835)
* Builder methods for WASI contexts now use `&mut self` instead of `self`.
[6770](https://github.com/bytecodealliance/wasmtime/pull/6770)
* Native unwinding information is now properly disabled when it is configured to
be turned off.
[6547](https://github.com/bytecodealliance/wasmtime/pull/6547)
* Wasmtime's minimum supported Rust version (MSRV) is now 1.70.0. Wasmtime's
MSRV policy of supporting the last three releases of Rust (N-2) is now
additionally documented. More discussion can additionally be found on the PR
itself.
[6900](https://github.com/bytecodealliance/wasmtime/pull/6900)
* Wasmtime's support for DWARF debugging information has seen some fixes for
previously reported crashes.
[6931](https://github.com/bytecodealliance/wasmtime/pull/6931)
Removed
* Wasmtime's experimental implementation of wasi-crypto has been removed. More
discussion of this change can be found on
[6732](https://github.com/bytecodealliance/wasmtime/pull/6732)
and
[6816](https://github.com/bytecodealliance/wasmtime/pull/6816)
* Support for `union` types in the component model has been removed.
[6913](https://github.com/bytecodealliance/wasmtime/pull/6913)
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