rust jit wasm webassembly runtime wasi cranelift sandbox wasmtime

History

Nick Fitzgerald 868f0c381c Wasmtime: Add support for Wasm tail calls (#6774 ) * Wasmtime: Add support for Wasm tail calls This adds the `Config::wasm_tail_call` method and `--wasm-features tail-call` CLI flag to enable the Wasm tail calls proposal in Wasmtime. This PR is mostly just plumbing and enabling tests, since all the prerequisite work (Wasmtime trampoline overhauls and Cranelift tail calls) was completed in earlier pull requests. When Wasm tail calls are enabled, Wasm code uses the `tail` calling convention. The `tail` calling convention is known to cause a 1-7% slow down for regular code that isn't using tail calls, which is why it isn't used unconditionally. This involved shepherding `Tunables` through to Wasm signature construction methods. The eventual plan is for the `tail` calling convention to be used unconditionally, but not until the performance regression is addressed. This work is tracked in https://github.com/bytecodealliance/wasmtime/issues/6759 Additionally while our x86-64, aarch64, and riscv64 backends support tail calls, the s390x backend does not support them yet. Attempts to use tail calls on s390x will return errors. Support for s390x is tracked in https://github.com/bytecodealliance/wasmtime/issues/6530 * Store `Tunables` inside the `Compiler` Instead of passing as an argument to every `Compiler` method. * Cranelift: Support "direct" return calls on riscv64 They still use `jalr` instead of `jal` but this allows us to use the `RiscvCall` reloc, which Wasmtime handles. Before we were using `LoadExternalName` which produces an `Abs8` reloc, which Wasmtime intentionally does not handle since that involves patching code at runtime, which makes loading code slower. * Fix tests that assume tail call support on s390x		1 year ago
..
src	Wasmtime: Add support for Wasm tail calls (#6774)	1 year ago
wasm-spec-interpreter	Add release notes for 3.0.1 and update some versions (#5364)	2 years ago
Cargo.toml	Update v8 and proc-macro2 dependencies (#6680)	1 year ago
README.md	Create a new `wasmtime-fuzzing` crate	5 years ago
build.rs	Actually make spectest fuzzing deterministic	4 years ago

README.md

Fuzzing Infrastructure for Wasmtime

This crate provides test case generators and oracles for use with fuzzing.

These generators and oracles are generally independent of the fuzzing engine that might be using them and driving the whole fuzzing process (e.g. libFuzzer or AFL). As such, this crate does not contain any actual fuzz targets itself. Those are generally just a couple lines of glue code that plug raw input from (for example) libFuzzer into a generator, and then run one or more oracles on the generated test case.

If you're looking for the actual fuzz target definitions we currently have, they live in wasmtime/fuzz/fuzz_targets/* and are driven by cargo fuzz and libFuzzer.