Added install_lucet_signal_handler() and remove_lucet_signal_handler(), along with Instance::ensure_signal_handler_installed() and Instance::ensure_sigstack_installed() options to control the automatic installation and removal of signal handlers and alternate signal stacks. The default behaviors have not changed.

Added Instance::run_start() to the public API, which runs the Wasm start function if it is present in that instance's Wasm module. It does nothing if there is no start function.

Creating or resetting an instance no longer implicitly runs the start function. Embedders must ensure that run_start() is called before calling any other exported functions. Instance::run() will now return Err(Error::InstanceNeedsStart) if the start function is present but hasn't been run since the instance was created or reset.

Encoded the Wasm start function in Lucet module metadata, rather than as a specially-named symbol in the shared object. This reduces contention from dlsym operations when multiple threads run Lucet instances concurrently.

Upgraded the libloading dependency, allowing for more specific error messages from dynamic loading operations.

Corrected a race condition where a KillSwitch fired while lucet-runtime is handling a guest fault could result in a SIGALRM or panic in the Lucet embedder.

Converted the &mut Vmctx argument to hostcalls into &Vmctx. Additionally, all Vmctx methods now take &self, where some methods such as yield previously took &mut self. These methods still require that no other outstanding borrows (such as the heap view) are held across them, but that property is checked dynamically rather than at compile time.

Added the field hostcall_reservation to Limits to specify an amount of stack space Lucet will ensure is available when making a hostcall. hostcall_reservation defaults to 32KiB. If there is less than the configured amount of stack space when making a hostcall, the instance will fault in the same way as any other guest-code stack overflow.

Added terminate_on_heap_oom as an option for instances. This causes instances to terminate with an OOM-specific termination value rather than returning -1 when a memory.grow instruction fails.

Added metadata to compiled modules that record whether instruction counting instrumentation is present.

Made lucetc more flexible in its interpretation of the LD environment variable. It now accepts a space-separated set of tokens; the first token specifies the program to invoke, and the remaining tokens specifying arguments to be passed to that program. Thanks, @froydnj!

Added public LucetcOpt methods to configure the canonicalize_nans setting. Thanks, @roman-kashitsyn!

Fixed lucet-runtime's use of CPUID to not look for extended features unless required by the module being loaded, avoiding a failure on older CPUs where that CPUID leaf is not present. Thanks, @shravanrn!

Added free_slots(), used_slots(), and capacity() methods to the Region trait.

Added a check to ensure the Limits signal stack size is at least MINSIGSTKSZ, and increased the default signal stack size on macOS debug builds to fit this constraint.

Added an option to canonicalize NaNs to the lucetc API. Thanks, @DavidM-D!

Restored some of the verbosity of pretty-printed errors in lucetc and lucet-validate, with more on the way.

Fixed OS detection for LDFLAGS on macOS. Thanks, @roman-kashitsyn!

Lucet officially became a project of the Bytecode Alliance 🎉.

Integrated wasi-common as the underlying implementation for WASI in lucet-wasi.

Updated to Cranelift to version 0.51.0.

Fixed a soundness bug by changing the types of the Vmctx::yield*() methods to require exclusive &mut self access to the Vmctx. This prevents resources like embedder contexts or heap views from living across yield points, which is important for safety since the host can modify the data underlying those resources while the instance is suspended.

Added the #[lucet_hostcall] attribute to replace lucet_hostcalls!, which is now deprecated.

Added the ability to specify an alignment for the base of a MmapRegion-backed instance's heap. Thanks, @shravanrn!

Added a --target option to lucetc to allow cross-compilation to other architectures than the host's. Thanks, @froydnj!

Changed the Cargo dependencies between Lucet crates to be exact (e.g., "=0.5.0" rather than "0.5.0") rather than allowing semver differences.

Fixed the KillSwitch type not being exported from the public API, despite being usable via Instance::kill_switch().

Improved the formatting of error messages.

Ensured the lucet-wasi executable properly links in the exported symbols from lucet-runtime.