* Exports symbols to be shared with external GDB/JIT debugging interface tools.
Windows O/S specific requirement.
* Moved comments into platform specific compiler directive sections.
* Use `__builtin_setjmp` instead of `sigsetjmp`.
Use [`__builtin_setjmp`] instead of `sigsetjmp`, as it is implemented in
the compiler, performed inline, and saves much less state. This speeds up
calls into wasm by about 8% on my machine.
[`__builtin_setjmp`]: https://gcc.gnu.org/onlinedocs/gcc/Nonlocal-Gotos.html
* Add a comment confirming that 5 really is the documented size.
* Add a comment about callee-saved state and __builtin_setjmp.
* On clang on aarch64, use sigsetjmp.
* Fix a stray `#endif`.
* Add differential fuzzing against V8
This commit adds a differential fuzzing target to Wasmtime along the
lines of the wasmi and spec interpreters we already have, but with V8
instead. The intention here is that wasmi is unlikely to receive updates
over time (e.g. for SIMD), and the spec interpreter is not suitable for
fuzzing against in general due to its performance characteristics. The
hope is that V8 is indeed appropriate to fuzz against because it's
naturally receiving updates and it also is expected to have good
performance.
Here the `rusty_v8` crate is used which provides bindings to V8 as well
as precompiled binaries by default. This matches exactly the use case we
need and at least for now I think the `rusty_v8` crate will be
maintained by the Deno folks as they continue to develop it. If it
becomes an issue though maintaining we can evaluate other options to
have differential fuzzing against.
For now this commit enables the SIMD and bulk-memory feature of
fuzz-target-generation which should enable them to get
differentially-fuzzed with V8 in addition to the compilation fuzzing
we're already getting.
* Use weak linkage for GDB jit helpers
This should help us deduplicate our symbol with other JIT runtimes, if
any. For now this leans on some C helpers to define the weak linkage
since Rust doesn't support that on stable yet.
* Don't use rusty_v8 on MinGW
They don't have precompiled libraries there.
* Fix msvc build
* Comment about execution
This commit adds a `#[link]` annotation to the block defining symbols
coming from a native static library that we build and link. This is
required by rustc to get symbols to get exported correctly when linking
wasmtime into a Rust dynamic library instead of always as an rlib.
While I was at it I went ahead and renamed the symbols now that they're
no longer in C++ and they're doing setjmp/longjmp and not much else.
Closes#3006
Implement Wasmtime's new API as designed by RFC 11. This is quite a large commit which has had lots of discussion externally, so for more information it's best to read the RFC thread and the PR thread.
Apparently on macOS `setjmp` manipulates the process-wide signal mask
which adds a good deal of overhead. We don't actually need this
functionality so this commit switches to using the `sig` version of
setjmp/longjmp where we can explicitly ask the signal mask to not get
preserved. This came out of poking around on #2644 and on macOS locally
thi sdropped the overhead from 721ns to 55ns.
This commit adds a few odds and ends required to build wasmtime on ARM64
with the new backend. In particular, it adds:
- Support for the `Arm64Call` relocation type.
- Support for fetching the trap PC when a signal is received.
- A hook for `SIGTRAP`, which is sent by the `brk` opcode (in contrast to
x86's `SIGILL`).
With the patch sequence up to and including this patch applied,
`wasmtime` can now compile and successfully execute code on arm64. Not
all tests pass yet, but basic Wasm/WASI tests work correctly.
* Remove C++ dependency from `wasmtime`
This commit removes the last wads of C++ that we have in wasmtime,
meaning that building wasmtime no longer requires a C++ compiler. It
still does require a C toolchain for some minor purposes, but hopefully
we can remove that over time too!
The motivation for doing this is to consolidate all our signal-handling
code into one location in one language so you don't have to keep
crossing back and forth when understanding what's going on. This also
allows us to remove some extra cruft that wasn't necessary from the C++
original implementation. Additionally this should also make building
wasmtime a bit more portable since it's often easier to acquire a C
toolchain than it is to acquire a C++ toolchain. (e.g. if you're
cross-compiling to a musl target)
* Typos
