* Remove the `jit_function_registry` global state
This commit removes on the final pieces of global state in wasmtime
today, the `jit_function_registry` module. The purpose of this module is
to help translate a native backtrace with native program counters into a
wasm backtrace with module names, function names, and wasm module
indices. To that end this module retained a global map of function
ranges to this metadata information for each compiled function.
It turns out that we already had a `NAMES` global in the `wasmtime`
crate for symbolicating backtrace addresses, so this commit moves that
global into its own file and restructures the internals to account for
program counter ranges as well. The general set of changes here are:
* Remove `jit_function_registry`
* Remove `NAMES`
* Create a new `frame_info` module which has a singleton global
registering compiled module's frame information.
* Update traps to use the `frame_info` module to symbolicate pcs,
directly extracting a `FrameInfo` from the module.
* Register and unregister information on a module level instead of on a
per-function level (at least in terms of locking granluarity).
This commit leaves the new `FRAME_INFO` global variable as the only
remaining "critical" global variable in `wasmtime`, which only exists
due to the API of `Trap` where it doesn't take in any extra context when
capturing a stack trace through which we could hang off frame
information. I'm thinking though that this is ok, and we can always
tweak the API of `Trap` in the future if necessary if we truly need to
accomodate this.
* Remove a lazy_static dep
* Add some comments and restructure
* Improve panics/traps from imported functions
This commit performs a few refactorings and fixes a bug as well. The
changes here are:
* The `thread_local!` in the `wasmtime` crate for trap information is
removed. The thread local in the `wasmtime_runtime` crate is now
leveraged to transmit trap information.
* Panics in user-provided functions are now caught explicitly to be
carried across JIT code manually. Getting Rust panics unwinding
through JIT code is pretty likely to be super tricky and difficult to
do, so in the meantime we can get by with catching panics and resuming
the panic once we've resumed in Rust code.
* Various take/record trap apis have all been removed in favor of
working directly with `Trap` objects, where the internal trap object
has been expanded slightly to encompass user-provided errors as well.
This borrows a bit #839 and otherwise will...
Closes#848
* Rename `r#return` to `ret`
* Improve handling of strings for backtraces
Largely avoid storing strings at all in the `wasmtime-*` internal
crates, and instead only store strings in a separate global cache
specific to the `wasmtime` crate itself. This global cache is inserted
and removed from dynamically as modules are created and deallocated, and
the global cache is consulted whenever a `Trap` is created to
symbolicate any wasm frames.
This also avoids the need to thread `module_name` through the jit crates
and back, and additionally removes the need for `ModuleSyncString`.
* Run rustfmt
* Preserve full native stack traces in errors
This commit builds on #759 by performing a few refactorings:
* The `backtrace` crate is updated to 0.3.42 which incorporates the
Windows-specific stack-walking code, so that's no longer needed.
* A full `backtrace::Backtrace` type is held in a trap at all times.
* The trap structures in the `wasmtime-*` internal crates were
refactored a bit to preserve more information and deal with raw
values rather than converting between various types and strings.
* The `wasmtime::Trap` type has been updated with these various changes.
Eventually I think we'll want to likely render full stack traces (and/or
partial wasm ones) into error messages, but for now that's left as-is
and we can always improve it later. I suspect the most relevant thing we
need to do is to implement function name symbolication for wasm
functions first, and then afterwards we can incorporate native function
names!
* Fix some test suite assertions
* Remove unsafety from `Trap` API
This commit removes the `unsafe impl Send` for `Trap` by removing the
internal `HostRef` and leaving `HostRef` entirely as an implementation
detail of the C API.
cc #708
* Run rustfmt
* Ensure `Trap` is returned for start function traps
Handle another case of errors coming out of instantiation, resolve a
FIXME, and remove an unneeded dependency from the wast testsuite crate.
* Run rustfmt
* Migrate back to `std::` stylistically
This commit moves away from idioms such as `alloc::` and `core::` as
imports of standard data structures and types. Instead it migrates all
crates to uniformly use `std::` for importing standard data structures
and types. This also removes the `std` and `core` features from all
crates to and removes any conditional checking for `feature = "std"`
All of this support was previously added in #407 in an effort to make
wasmtime/cranelift "`no_std` compatible". Unfortunately though this
change comes at a cost:
* The usage of `alloc` and `core` isn't idiomatic. Especially trying to
dual between types like `HashMap` from `std` as well as from
`hashbrown` causes imports to be surprising in some cases.
* Unfortunately there was no CI check that crates were `no_std`, so none
of them actually were. Many crates still imported from `std` or
depended on crates that used `std`.
It's important to note, however, that **this does not mean that wasmtime
will not run in embedded environments**. The style of the code today and
idioms aren't ready in Rust to support this degree of multiplexing and
makes it somewhat difficult to keep up with the style of `wasmtime`.
Instead it's intended that embedded runtime support will be added as
necessary. Currently only `std` is necessary to build `wasmtime`, and
platforms that natively need to execute `wasmtime` will need to use a
Rust target that supports `std`. Note though that not all of `std` needs
to be supported, but instead much of it could be configured off to
return errors, and `wasmtime` would be configured to gracefully handle
errors.
The goal of this PR is to move `wasmtime` back to idiomatic usage of
features/`std`/imports/etc and help development in the short-term.
Long-term when platform concerns arise (if any) they can be addressed by
moving back to `no_std` crates (but fixing the issues mentioned above)
or ensuring that the target in Rust has `std` available.
* Start filling out platform support doc
