830885383f2fefca7ad06f9d901b9376237fab6c
6 Commits
| Author | SHA1 | Message | Date | |
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Alex Crichton
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b305f251fb |
Update the wasm-tools family of crates (#5310)
Most of the changes here are the updates to the component model which includes optional URL fields in imports/exports. |
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Alex Crichton
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2afaac5181 |
Return anyhow::Error from host functions instead of Trap, redesign Trap (#5149)
* Return `anyhow::Error` from host functions instead of `Trap` This commit refactors how errors are modeled when returned from host functions and additionally refactors how custom errors work with `Trap`. At a high level functions in Wasmtime that previously worked with `Result<T, Trap>` now work with `Result<T>` instead where the error is `anyhow::Error`. This includes functions such as: * Host-defined functions in a `Linker<T>` * `TypedFunc::call` * Host-related callbacks like call hooks Errors are now modeled primarily as `anyhow::Error` throughout Wasmtime. This subsequently removes the need for `Trap` to have the ability to represent all host-defined errors as it previously did. Consequently the `From` implementations for any error into a `Trap` have been removed here and the only embedder-defined way to create a `Trap` is to use `Trap::new` with a custom string. After this commit the distinction between a `Trap` and a host error is the wasm backtrace that it contains. Previously all errors in host functions would flow through a `Trap` and get a wasm backtrace attached to them, but now this only happens if a `Trap` itself is created meaning that arbitrary host-defined errors flowing from a host import to the other side won't get backtraces attached. Some internals of Wasmtime itself were updated or preserved to use `Trap::new` to capture a backtrace where it seemed useful, such as when fuel runs out. The main motivation for this commit is that it now enables hosts to thread a concrete error type from a host function all the way through to where a wasm function was invoked. Previously this could not be done since the host error was wrapped in a `Trap` that didn't provide the ability to get at the internals. A consequence of this commit is that when a host error is returned that isn't a `Trap` we'll capture a backtrace and then won't have a `Trap` to attach it to. To avoid losing the contextual information this commit uses the `Error::context` method to attach the backtrace as contextual information to ensure that the backtrace is itself not lost. This is a breaking change for likely all users of Wasmtime, but it's hoped to be a relatively minor change to workaround. Most use cases can likely change `-> Result<T, Trap>` to `-> Result<T>` and otherwise explicit creation of a `Trap` is largely no longer necessary. * Fix some doc links * add some tests and make a backtrace type public (#55) * Trap: avoid a trailing newline in the Display impl which in turn ends up with three newlines between the end of the backtrace and the `Caused by` in the anyhow Debug impl * make BacktraceContext pub, and add tests showing downcasting behavior of anyhow::Error to traps or backtraces * Remove now-unnecesary `Trap` downcasts in `Linker::module` * Fix test output expectations * Remove `Trap::i32_exit` This commit removes special-handling in the `wasmtime::Trap` type for the i32 exit code required by WASI. This is now instead modeled as a specific `I32Exit` error type in the `wasmtime-wasi` crate which is returned by the `proc_exit` hostcall. Embedders which previously tested for i32 exits now downcast to the `I32Exit` value. * Remove the `Trap::new` constructor This commit removes the ability to create a trap with an arbitrary error message. The purpose of this commit is to continue the prior trend of leaning into the `anyhow::Error` type instead of trying to recreate it with `Trap`. A subsequent simplification to `Trap` after this commit is that `Trap` will simply be an `enum` of trap codes with no extra information. This commit is doubly-motivated by the desire to always use the new `BacktraceContext` type instead of sometimes using that and sometimes using `Trap`. Most of the changes here were around updating `Trap::new` calls to `bail!` calls instead. Tests which assert particular error messages additionally often needed to use the `:?` formatter instead of the `{}` formatter because the prior formats the whole `anyhow::Error` and the latter only formats the top-most error, which now contains the backtrace. * Merge `Trap` and `TrapCode` With prior refactorings there's no more need for `Trap` to be opaque or otherwise contain a backtrace. This commit parse down `Trap` to simply an `enum` which was the old `TrapCode`. All various tests and such were updated to handle this. The main consequence of this commit is that all errors have a `BacktraceContext` context attached to them. This unfortunately means that the backtrace is printed first before the error message or trap code, but given all the prior simplifications that seems worth it at this time. * Rename `BacktraceContext` to `WasmBacktrace` This feels like a better name given how this has turned out, and additionally this commit removes having both `WasmBacktrace` and `BacktraceContext`. * Soup up documentation for errors and traps * Fix build of the C API Co-authored-by: Pat Hickey <pat@moreproductive.org> |
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Pat Hickey
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78ecc17d0f |
unsplat component::Linker::func_wrap args (#5065)
* component::Linker::func_wrap: replace IntoComponentFunc with directly accepting a closure We find that this makes the Linker::func_wrap type signature much easier to read. The IntoComponentFunc abstraction was adding a lot of weight to "splat" a set of arguments from a tuple of types into individual arguments to the closure. Additionally, making the StoreContextMut argument optional, or the Result<return> optional, wasn't very worthwhile. * Fixes for the new style of closure required by component::Linker::func_wrap * fix fuzzing generator |
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Alex Crichton
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29c7de7340 |
Update wasm-tools dependencies (#4970)
* Update wasm-tools dependencies This update brings in a number of features such as: * The component model binary format and AST has been slightly adjusted in a few locations. Names are dropped from parameters/results now in the internal representation since they were not used anyway. At this time the ability to bind a multi-return function has not been exposed. * The `wasmparser` validator pass will now share allocations with prior functions, providing what's probably a very minor speedup for Wasmtime itself. * The text format for many component-related tests now requires named parameters. * Some new relaxed-simd instructions are updated to be ignored. I hope to have a follow-up to expose the multi-return ability to the embedding API of components. * Update audit information for new crates |
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Alex Crichton
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57dca934ad |
Upgrade wasm-tools crates, namely the component model (#4715)
* Upgrade wasm-tools crates, namely the component model This commit pulls in the latest versions of all of the `wasm-tools` family of crates. There were two major changes that happened in `wasm-tools` in the meantime: * bytecodealliance/wasm-tools#697 - this commit introduced a new API for more efficiently reading binary operators from a wasm binary. The old `Operator`-based reading was left in place, however, and continues to be what Wasmtime uses. I hope to update Wasmtime in a future PR to use this new API, but for now the biggest change is... * bytecodealliance/wasm-tools#703 - this commit was a major update to the component model AST. This commit almost entirely deals with the fallout of this change. The changes made to the component model were: 1. The `unit` type no longer exists. This was generally a simple change where the `Unit` case in a few different locations were all removed. 2. The `expected` type was renamed to `result`. This similarly was relatively lightweight and mostly just a renaming on the surface. I took this opportunity to rename `val::Result` to `val::ResultVal` and `types::Result` to `types::ResultType` to avoid clashing with the standard library types. The `Option`-based types were handled with this as well. 3. The payload type of `variant` and `result` types are now optional. This affected many locations that calculate flat type representations, ABI information, etc. The `#[derive(ComponentType)]` macro now specifically handles Rust-defined `enum` types which have no payload to the equivalent in the component model. 4. Functions can now return multiple parameters. This changed the signature of invoking component functions because the return value is now bound by `ComponentNamedList` (renamed from `ComponentParams`). This had a large effect in the tests, fuzz test case generation, etc. 5. Function types with 2-or-more parameters/results must uniquely name all parameters/results. This mostly affected the text format used throughout the tests. I haven't added specifically new tests for multi-return but I changed a number of tests to use it. Additionally I've updated the fuzzers to all exercise multi-return as well so I think we should get some good coverage with that. * Update version numbers * Use crates.io |
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Alex Crichton
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650979ae40 |
Implement strings in adapter modules (#4623)
* Implement strings in adapter modules This commit is a hefty addition to Wasmtime's support for the component model. This implements the final remaining type (in the current type hierarchy) unimplemented in adapter module trampolines: strings. Strings are the most complicated type to implement in adapter trampolines because they are highly structured chunks of data in memory (according to specific encodings). Additionally each lift/lower operation can choose its own encoding for strings meaning that Wasmtime, the host, may have to convert between any pairwise ordering of string encodings. The `CanonicalABI.md` in the component-model repo in general specifies all the fiddly bits of string encoding so there's not a ton of wiggle room for Wasmtime to get creative. This PR largely "just" implements that. The high-level architecture of this implementation is: * Fused adapters are first identified to determine src/dst string encodings. This statically fixes what transcoding operation is being performed. * The generated adapter will be responsible for managing calls to `realloc` and performing bounds checks. The adapter itself does not perform memory copies or validation of string contents, however. Instead each transcoding operation is modeled as an imported function into the adapter module. This means that the adapter module dynamically, during compile time, determines what string transcoders are needed. Note that an imported transcoder is not only parameterized over the transcoding operation but additionally which memory is the source and which is the destination. * The imported core wasm functions are modeled as a new `CoreDef::Transcoder` structure. These transcoders end up being small Cranelift-compiled trampolines. The Cranelift-compiled trampoline will load the actual base pointer of memory and add it to the relative pointers passed as function arguments. This trampoline then calls a transcoder "libcall" which enters Rust-defined functions for actual transcoding operations. * Each possible transcoding operation is implemented in Rust with a unique name and a unique signature depending on the needs of the transcoder. I've tried to document inline what each transcoder does. This means that the `Module::translate_string` in adapter modules is by far the largest translation method. The main reason for this is due to the management around calling the imported transcoder functions in the face of validating string pointer/lengths and performing the dance of `realloc`-vs-transcode at the right time. I've tried to ensure that each individual case in transcoding is documented well enough to understand what's going on as well. Additionally in this PR is a full implementation in the host for the `latin1+utf16` encoding which means that both lifting and lowering host strings now works with this encoding. Currently the implementation of each transcoder function is likely far from optimal. Where possible I've leaned on the standard library itself and for latin1-related things I'm leaning on the `encoding_rs` crate. I initially tried to implement everything with `encoding_rs` but was unable to uniformly do so easily. For now I settled on trying to get a known-correct (even in the face of endianness) implementation for all of these transcoders. If an when performance becomes an issue it should be possible to implement more optimized versions of each of these transcoding operations. Testing this commit has been somewhat difficult and my general plan, like with the `(list T)` type, is to rely heavily on fuzzing to cover the various cases here. In this PR though I've added a simple test that pushes some statically known strings through all the pairs of encodings between source and destination. I've attempted to pick "interesting" strings that one way or another stress the various paths in each transcoding operation to ideally get full branch coverage there. Additionally a suite of "negative" tests have also been added to ensure that validity of encoding is actually checked. * Fix a temporarily commented out case * Fix wasmtime-runtime tests * Update deny.toml configuration * Add `BSD-3-Clause` for the `encoding_rs` crate * Remove some unused licenses * Add an exemption for `encoding_rs` for now * Split up the `translate_string` method Move out all the closures and package up captured state into smaller lists of arguments. * Test out-of-bounds for zero-length strings |