* Reduce number of thread locals in trap handling
This commit refactors the trap handling portion of wasmtime with a few
goals in mind. I've been reading around a bit lately and feel that we
have a bit too few globals and thread locals floating around rather than
handles attached to contexts. I'm hoping that we can reduce the number
of thread locals and globals, and this commit is the start of reducing
this number.
The changes applied in this commit remove the set of thread locals in
the `traphandlers` module in favor of one thread local that's managed in
a sort of stack discipline. This way each call to `wasmtime_call*` sets
up its own stack local state that can be managed and read on that stack
frame.
Additionally the C++ glue code around `setjmp` and `longjmp` has all
been refactored to avoid going back and forth between Rust and C++. Now
we'll simply enter C++, go straight into `setjmp`/the call, and then
traps will enter Rust only once to both learn if the trap should be
acted upon and record information about the trap.
Overall the hope here is that context passing between `wasmtime_call*`
and the trap handling function will be a bit easier. For example I hope
to remove the global `get_trap_registry()` function next in favor of
storing a handle to a registry inside each instance, and the `*mut
VMContext` can be used to reach the `InstanceHandle` underneath, and
this trap registry.
* Update crates/runtime/src/traphandlers.rs
Co-Authored-By: Sergei Pepyakin <s.pepyakin@gmail.com>
Co-authored-by: Sergei Pepyakin <s.pepyakin@gmail.com>
* Replace the global-exports mechanism with a caller-vmctx mechanism.
This eliminates the global exports mechanism, and instead adds a
caller-vmctx argument to wasm functions so that WASI can obtain the
memory and other things from the caller rather than looking them up in a
global registry.
This replaces #390.
* Fixup some merge conflicts
* Rustfmt
* Ensure VMContext is aligned to 16 bytes
With the removal of `global_exports` it "just so happens" that this
isn't happening naturally any more.
* Fixup some bugs with double vmctx in wasmtime crate
* Trampoline stub needed adjusting
* Use pointer type instead of always using I64 for caller vmctx
* Don't store `ir::Signature` in `Func` since we don't know the pointer
size at creation time.
* Skip the first 2 arguments in IR signatures since that's the two vmctx
parameters.
* Update cranelift to 0.56.0
* Handle more merge conflicts
* Rustfmt
Co-authored-by: Alex Crichton <alex@alexcrichton.com>
