cranelift

Commit Graph

Author	SHA1	Message	Date
Nick Fitzgerald	6a7ef27b72	Make `wasmtime::WasmCoreDump` serializable (#7078 ) This commit makes it so that the library type for core dumps is serializable into the standard binary format for core dumps. Additionally, this commit makes it so that we use the library type for generating core dumps in the CLI. We previously were using a one-off implementation of core dump generation that only had backtrace information and no instances, modules, globals, or memories included. The library type has all that information, so the core dumps produced by our CLI will both be more featureful and be generated by shared code paths going forward. Along the way, implementing all this required some new helper methods sprinkled throughout `wasmtime` and `wasmtime-runtime`: * `wasmtime::Instance::module`: get the module that a `wasmtime::Instance` is an instance of. This is public, since it seems generally useful. This involved adding a new return value from `ModuleRegistry::register_module` that is an identifier that can be used to recover a reference to the registered module. * `wasmtime::Instance::all_{globals,memories}`: get the full global/memory index space. I made these `pub(crate)` out of caution. I don't think we want to commit to exposing non-exported things in the public API, even if we internally need them for debugging-related features like core dumps. These also needed corresponding methods inside `wasmtime-runtime`. * `wasmtime::{Global,Memory}::hash_key`: this was needed to work around the fact that each time you call `{Global,Memory}::from_wasmtime`, it creates a new entry in the `StoreData` and so you can get duplicates. But we need to key some hash maps on globals and memories when constructing core dumps, so we can't treat the underlying `Stored<T>` as a hash key because it isn't stable across duplicate `StoreData` entries. So we have these new methods. They are only `pub(crate)`, are definitely implementation details, and aren't exposed in the public API. * `wasmtime::FrameInfo::module`: Each frame in a backtrace now keeps a handle to its associated module instead of just the name. This is publicly exposed because it seems generally useful. This means I also deprecated `wasmtime::FrameInfo::module_name` since you can now instead do `frame.module().name()` to get that exact same info. I updated callers inside the repo.	1 year ago
guregu	7dfae4c38e	Ignore async_stack_size if async_support is disabled (#6771 ) Fixes an issue where max_wasm_stack was being validated against async_stack_size when async_support was disabled, discussed in #6762.	1 year ago
Alex Crichton	c0bb341d95	Run some tests in MIRI on CI (#6332 ) * Run some tests in MIRI on CI This commit is an implementation of getting at least chunks of Wasmtime to run in MIRI on CI. The full test suite is not possible to run in MIRI because MIRI cannot run Cranelift-produced code at runtime (aka it doesn't support JITs). Running MIRI, however, is still quite valuable if we can manage it because it would have trivially detected GHSA-ch89-5g45-qwc7, our most recent security advisory. The goal of this PR is to select a subset of the test suite to execute in CI under MIRI and boost our confidence in the copious amount of `unsafe` code in Wasmtime's runtime. Under MIRI's default settings, which is to use the [Stacked Borrows][stacked] model, much of the code in `Instance` and `VMContext` is considered invalid. Under the optional [Tree Borrows][tree] model, however, this same code is accepted. After some [extremely helpful discussion][discuss] on the Rust Zulip my current conclusion is that what we're doing is not fundamentally un-sound but we need to model it in a different way. This PR, however, uses the Tree Borrows model for MIRI to get something onto CI sooner rather than later, and I hope to follow this up with something that passed Stacked Borrows. Additionally that'll hopefully make this diff smaller and easier to digest. Given all that, the end result of this PR is to get 131 separate unit tests executing on CI. These unit tests largely exercise the embedding API where wasm function compilation is not involved. Some tests compile wasm functions but don't run them, but compiling wasm through Cranelift in MIRI is so slow that it doesn't seem worth it at this time. This does mean that there's a pretty big hole in MIRI's test coverage, but that's to be expected as we're a JIT compiler after all. To get tests working in MIRI this PR uses a number of strategies: * When platform-specific code is involved there's now `#[cfg(miri)]` for MIRI's version. For example there's a custom-built "mmap" just for MIRI now. Many of these are simple noops, some are `unimplemented!()` as they shouldn't be reached, and some are slightly nontrivial implementations such as mmaps and trap handling (for native-to-native function calls). * Many test modules are simply excluded via `#![cfg(not(miri))]` at the top of the file. This excludes the entire module's worth of tests from MIRI. Other modules have `#[cfg_attr(miri, ignore)]` annotations to ignore tests by default on MIRI. The latter form is used in modules where some tests work and some don't. This means that all future test additions will need to be effectively annotated whether they work in MIRI or not. My hope though is that there's enough precedent in the test suite of what to do to not cause too much burden. * A number of locations are fixed with respect to MIRI's analysis. For example `ComponentInstance`, the component equivalent of `wasmtime_runtime::Instance`, was actually left out from the fix for the CVE by accident. MIRI dutifully highlighted the issues here and I've fixed them locally. Some locations fixed for MIRI are changed to something that looks similar but is subtly different. For example retaining items in a `Store<T>` is now done with a Wasmtime-specific `StoreBox<T>` type. This is because, with MIRI's analyses, moving a `Box<T>` invalidates all pointers derived from this `Box<T>`. We don't want these semantics, so we effectively have a custom `Box<T>` to suit our needs in this regard. * Some default configuration is different under MIRI. For example most linear memories are dynamic with no guards and no space reserved for growth. Settings such as parallel compilation are disabled. These are applied to make MIRI "work by default" in more places ideally. Some tests which perform N iterations of something perform fewer iterations on MIRI to not take quite so long. This PR is not intended to be a one-and-done-we-never-look-at-it-again kind of thing. Instead this is intended to lay the groundwork to continuously run MIRI in CI to catch any soundness issues. This feels, to me, overdue given the amount of `unsafe` code inside of Wasmtime. My hope is that over time we can figure out how to run Wasm in MIRI but that may take quite some time. Regardless this will be adding nontrivial maintenance work to contributors to Wasmtime. MIRI will be run on CI for merges, MIRI will have test failures when everything else passes, MIRI's errors will need to be deciphered by those who have probably never run MIRI before, things like that. Despite all this to me it seems worth the cost at this time. Just getting this running caught two possible soundness bugs in the component implementation that could have had a real-world impact in the future! [stacked]: https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md [tree]: https://perso.crans.org/vanille/treebor/ [discuss]: https://rust-lang.zulipchat.com/#narrow/stream/269128-miri/topic/Tree.20vs.20Stacked.20Borrows.20.26.20a.20debugging.20question * Update alignment comment	2 years ago
Nick Fitzgerald	60ce6f5d5c	`wasmtime`: Fix resetting stack-walking registers when entering/exiting Wasm (#6321 ) * wasmtime: Fix resetting stack-walking registers when entering/exiting Wasm Fixes a regression from #6262, originally reported in https://github.com/bytecodealliance/wasmtime-dotnet/pull/245 The issue was that we would enter Wasm and save the stack-walking registers but never clear them after Wasm returns. Then if a host-to-host call tried to capture a stack, we would mistakenly attempt to use those stale registers to start the stack walk. This mistake would be caught by an assertion, triggering a panic. This commit fixes the issue by managing the save/restore in the `CallThreadState` construction/drop, rather than in the old `set_prev` method. Co-Authored-By: Alex Crichton <alex@alexcrichton.com> * Plumb through `VMRuntimeLimits` when capturing stack traces This way we can differentiate between the same module loaded in different stores and avoid leaking other stores' frames into our backtraces. Co-Authored-By: Jamey Sharp <jsharp@fastly.com> --------- Co-authored-by: Alex Crichton <alex@alexcrichton.com> Co-authored-by: Jamey Sharp <jsharp@fastly.com>	2 years ago
Nick Fitzgerald	913efdf24d	wasmtime: Overhaul trampolines (#6262 ) This commit splits `VMCallerCheckedFuncRef::func_ptr` into three new function pointers: `VMCallerCheckedFuncRef::{wasm,array,native}_call`. Each one has a dedicated calling convention, so callers just choose the version that works for them. This is as opposed to the previous behavior where we would chain together many trampolines that converted between calling conventions, sometimes up to four on the way into Wasm and four more on the way back out. See [0] for details. [0] https://github.com/bytecodealliance/rfcs/blob/main/accepted/tail-calls.md#a-review-of-our-existing-trampolines-calling-conventions-and-call-paths Thanks to @bjorn3 for the initial idea of having multiple function pointers for different calling conventions. This is generally a nice ~5-10% speed up to our call benchmarks across the board: both Wasm-to-host and host-to-Wasm. The one exception is typed calls from Wasm to the host, which have a minor regression. We hypothesize that this is because the old hand-written assembly trampolines did not maintain a call frame and do a tail call, but the new Cranelift-generated trampolines do maintain a call frame and do a regular call. The regression is only a couple nanoseconds, which seems well-explained by these differences explain, and ultimately is not a big deal. However, this does lead to a ~5% code size regression for compiled modules. Before, we compiled a trampoline per escaping function's signature and we deduplicated these trampolines by signature. Now we compile two trampolines per escaping function: one for if the host calls via the array calling convention and one for it the host calls via the native calling convention. Additionally, we compile a trampoline for every type in the module, in case there is a native calling convention function from the host that we `call_indirect` of that type. Much of this is in the `.eh_frame` section in the compiled module, because each of our trampolines needs an entry there. Note that the `.eh_frame` section is not required for Wasmtime's correctness, and you can disable its generation to shrink compiled module code size; we just emit it to play nice with external unwinders and profilers. We believe there are code size gains available for follow up work to offset this code size regression in the future. Backing up a bit: the reason each Wasm module needs to provide these Wasm-to-native trampolines is because `wasmtime::Func::wrap` and friends allow embedders to create functions even when there is no compiler available, so they cannot bring their own trampoline. Instead the Wasm module has to supply it. This in turn means that we need to look up and patch in these Wasm-to-native trampolines during roughly instantiation time. But instantiation is super hot, and we don't want to add more passes over imports or any extra work on this path. So we integrate with `wasmtime::InstancePre` to patch these trampolines in ahead of time. Co-Authored-By: Jamey Sharp <jsharp@fastly.com> Co-Authored-By: Alex Crichton <alex@alexcrichton.com> prtest:full	2 years ago
Alex Crichton	a3b21031d4	Add a `MachBuffer::defer_trap` method (#6011 ) * Add a `MachBuffer::defer_trap` method This commit adds a new method to `MachBuffer` to defer trap opcodes to the end of a function in a similar manner to how constants are deferred to the end of the function. This is useful for backends which frequently use `TrapIf`-style opcodes. Currently a jump is emitted which skips the next instruction, a trap, and then execution continues normally. While there isn't any pressing problem with this construction the trap opcode is in the middle of the instruction stream as opposed to "off on the side" despite rarely being taken. With this method in place all the backends (except riscv64 since I couldn't figure it out easily enough) have a new lowering of their `TrapIf` opcode. Now a trap is deferred, which returns a label, and then that label is jumped to when executing the trap. A fixup is then recorded in `MachBuffer` to get patched later on during emission, or at the end of the function. Subsequently all `TrapIf` instructions translate to a single branch plus a single trap at the end of the function. I've additionally further updated some more lowerings in the x64 backend which were explicitly using traps to instead use `TrapIf` where applicable to avoid jumping over traps mid-function. Other backends didn't appear to have many jump-over-the-next-trap patterns. Lots of tests have had their expectations updated here which should reflect all the traps being sunk to the end of functions. * Print trap code on all platforms * Emit traps before constants * Preserve source location information for traps * Fix test expectations * Attempt to fix s390x The MachBuffer was registering trap codes with the first byte of the trap, but the SIGILL handler was expecting it to be registered with the last byte of the trap. Exploit that SIGILL is always represented with a 2-byte instruction and always march 2-backwards for SIGILL, continuing to march backwards 1 byte for SIGFPE-generating instructions. * Back out s390x changes * Back out more s390x bits * Review comments	2 years ago
Alex Crichton	28371bfd40	Validate faulting addresses are valid to fault on (#6028 ) * Validate faulting addresses are valid to fault on This commit adds a defense-in-depth measure to Wasmtime which is intended to mitigate the impact of CVEs such as GHSA-ff4p-7xrq-q5r8. Currently Wasmtime will catch `SIGSEGV` signals for WebAssembly code so long as the instruction which faulted is an allow-listed instruction (aka has a trap code listed for it). With the recent security issue, however, the problem was that a wasm guest could exploit a compiler bug to access memory outside of its sandbox. If the access was successful there's no real way to detect that, but if the access was unsuccessful then Wasmtime would happily swallow the `SIGSEGV` and report a nominal trap. To embedders, this might look like nothing is going awry. The new strategy implemented here in this commit is to attempt to be more robust towards these sorts of failures. When a `SIGSEGV` is raised the faulting pc is recorded but additionally the address of the inaccessible location is also record. After the WebAssembly stack is unwound and control returns to Wasmtime which has access to a `Store` Wasmtime will now use this inaccessible faulting address to translate it to a wasm address. This process should be guaranteed to succeed as WebAssembly should only be able to access a well-defined region of memory for all linear memories in a `Store`. If no linear memory in a `Store` could contain the faulting address, then Wasmtime now prints a scary message and aborts the process. The purpose of this is to catch these sorts of bugs, make them very loud errors, and hopefully mitigate impact. This would continue to not mitigate the impact of a guest successfully loading data outside of its sandbox, but if a guest was doing a sort of probing strategy trying to find valid addresses then any invalid access would turn into a process crash which would immediately be noticed by embedders. While I was here I went ahead and additionally took a stab at #3120. Traps due to `SIGSEGV` will now report the size of linear memory and the address that was being accessed in addition to the bland "access out of bounds" error. While this is still somewhat bland in the context of a high level source language it's hopefully at least a little bit more actionable for some. I'll note though that this isn't a guaranteed contextual message since only the default configuration for Wasmtime generates `SIGSEGV` on out-of-bounds memory accesses. Dynamically bounds-checked configurations, for example, don't do this. Testing-wise I unfortunately am not aware of a great way to test this. The closet equivalent would be something like an `unsafe` method `Config::allow_wasm_sandbox_escape`. In lieu of adding tests, though, I can confirm that during development the crashing messages works just fine as it took awhile on macOS to figure out where the faulting address was recorded in the exception information which meant I had lots of instances of recording an address of a trap not accessible from wasm. * Fix tests * Review comments * Fix compile after refactor * Fix compile on macOS * Fix trap test for s390x s390x rounds faulting addresses to 4k boundaries.	2 years ago
Alex Crichton	5ae8575296	x64: Take SIGFPE signals for divide traps (#6026 ) * x64: Take SIGFPE signals for divide traps Prior to this commit Wasmtime would configure `avoid_div_traps=true` unconditionally for Cranelift. This, for the division-based instructions, would change emitted code to explicitly trap on trap conditions instead of letting the `div` x86 instruction trap. There's no specific reason for Wasmtime, however, to specifically avoid traps in the `div` instruction. This means that the extra generated branches on x86 aren't necessary since the `div` and `idiv` instructions already trap for similar conditions as wasm requires. This commit instead disables the `avoid_div_traps` setting for Wasmtime's usage of Cranelift. Subsequently the codegen rules were updated slightly: * When `avoid_div_traps=true`, traps are no longer emitted for `div` instructions. * The `udiv`/`urem` instructions now list their trap as divide-by-zero instead of integer overflow. * The lowering for `sdiv` was updated to still explicitly check for zero but the integer overflow case is deferred to the instruction itself. * The lowering of `srem` no longer checks for zero and the listed trap for the `div` instruction is a divide-by-zero. This means that the codegen for `udiv` and `urem` no longer have any branches. The codegen for `sdiv` removes one branch but keeps the zero-check to differentiate the two kinds of traps. The codegen for `srem` removes one branch but keeps the -1 check since the semantics of `srem` mismatch with the semantics of `idiv` with a -1 divisor (specifically for INT_MIN). This is unlikely to have really all that much of a speedup but was something I noticed during #6008 which seemed like it'd be good to clean up. Plus Wasmtime's signal handling was already set up to catch `SIGFPE`, it was just never firing. * Remove the `avoid_div_traps` cranelift setting With no known users currently removing this should be possible and helps simplify the x64 backend. * x64: GC more support for avoid_div_traps Remove the `validate_sdiv_divisor` pseudo-instructions and clean up some of the ISLE rules now that `div` is allowed to itself trap unconditionally. x64: Store div trap code in instruction itself * Keep divisors in registers, not in memory Don't accidentally fold multiple traps together * Handle EXC_ARITHMETIC on macos * Update emit tests * Update winch and tests	2 years ago
Alex Crichton	138a76df5d	Fix a debug assert with `wasm_backtrace(false)` (#5580 ) This commit fixes an issue where when backtraces were disabled but a host function returned an error it would trigger a debug assertion within Wasmtime. The fix here is to update the condition of the debug assertion and add a test doing this behavior to ensure it works in the future. I've also further taken the liberty in this commit to remove the deprecation notice for `Config::wasm_backtrace`. We don't really have a strong reason for removing this functionality at this time and users have multiple times now reported issues with performance that seem worthwhile to keep the option. The latest issue, #5577, has a use case where it appears the quadratic behavior is back in a way that Wasmtime won't be able to detect. Namely with lots of wasm interleaved with host on the stack if the original error isn't threaded through the entire time then each host error will trigger a new backtrace since it doesn't see a prior backtrace in the error being returned. While this could otherwise be fixed with only capturing one contiguous backtrace perhaps this seems reasonable enough to leave the `wasm_backtrace` config option for now. Closes #5577	2 years ago
Jake Champion	0a6a28a4fb	fix typo in hint about WASMTIME_BACKTRACE_DETAILS env var (#5443 ) * fix typo in hint about WASMTIME_BACKTRACE_DETAILS env var * Update traps.rs	2 years ago
Alex Crichton	ed6769084b	Add a `WasmBacktrace::new()` constructor (#5341 ) * Add a `WasmBacktrace::new()` constructor This commit adds a method of manually capturing a backtrace of WebAssembly frames within a `Store`. The new constructor can be called with any `AsContext` values, primarily `&Store` and `&Caller`, during host functions to inspect the calling state. For now this does not respect the `Config::wasm_backtrace` option and instead unconditionally captures the backtrace. It's hoped that this can continue to adapt to needs of embedders by making it more configurable int he future if necessary. Closes #5339 * Split `new` into `capture` and `force_capture`	2 years ago
Alex Crichton	b0939f6626	Remove explicit `S` type parameters (#5275 ) * Remove explicit `S` type parameters This commit removes the explicit `S` type parameter on `Func::typed` and `Instance::get_typed_func`. Historical versions of Rust required that this be a type parameter but recent rustcs support a mixture of explicit type parameters and `impl Trait`. This removes, at callsites, a superfluous `, _` argument which otherwise never needs specification. * Fix mdbook examples	2 years ago
Alex Crichton	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>	2 years ago
Nick Fitzgerald	a2f846f124	Don't re-capture backtraces when propagating traps through host frames (#5049 ) * Add a benchmark for traps with many Wasm<-->host calls on the stack * Add a test for expected Wasm stack traces with Wasm<--host calls on the stack when we trap * Don't re-capture backtraces when propagating traps through host frames This fixes some accidentally quadratic code where we would re-capture a Wasm stack trace (takes `O(n)` time) every time we propagated a trap through a host frame back to Wasm (can happen `O(n)` times). And `O(n) * O(n) = O(n^2)`, of course. Whoops. After this commit, it trapping with a call stack that is `n` frames deep of Wasm-to-host-to-Wasm calls just captures a single backtrace and is therefore just a proper `O(n)` time operation, as it is intended to be. Now we explicitly track whether we need to capture a Wasm backtrace or not when raising a trap. This unfortunately isn't as straightforward as one might hope, however, because of the split between `wasmtime::Trap` and `wasmtime_runtime::Trap`. We need to decide whether or not to capture a Wasm backtrace inside `wasmtime_runtime` but in order to determine whether to do that or not we need to reflect on the `anyhow::Error` and see if it is a `wasmtime::Trap` that already has a backtrace or not. This can't be done the straightforward way because it would introduce a cyclic dependency between the `wasmtime` and `wasmtime-runtime` crates. We can't merge those two `Trap` types-- at least not without effectively merging the whole `wasmtime` and `wasmtime-runtime` crates together, which would be a good idea in a perfect world but would be a ton of ocean boiling from where we currently are -- because `wasmtime::Trap` does symbolication of stack traces which relies on module registration information data that resides inside the `wasmtime` crate and therefore can't be moved into `wasmtime-runtime`. We resolve this problem by adding a boolean to `wasmtime_runtime::raise_user_trap` that controls whether we should capture a Wasm backtrace or not, and then determine whether we need a backtrace or not at each of that function's call sites, which are in `wasmtime` and therefore can do the reflection to determine whether the user trap already has a backtrace or not. Phew! Fixes #5037 * debug assert that we don't record unnecessary backtraces for traps * Add assertions around `needs_backtrace` Unfortunately we can't do debug_assert_eq!(needs_backtrace, trap.inner.backtrace.get().is_some()); because `needs_backtrace` doesn't consider whether Wasm backtraces have been disabled via config. * Consolidate `needs_backtrace` calculation followed by calling `raise_user_trap` into one place	2 years ago
Nick Fitzgerald	ff0e84ecf4	Wasmtime: fix stack walking across frames from different stores (#4779 ) We were previously implicitly assuming that all Wasm frames in a stack used the same `VMRuntimeLimits` as the previous frame we walked, but this is not true when Wasm in store A calls into the host which then calls into Wasm in store B: \| ... \| \| Host \| \| +-----------------+ \| stack \| Wasm in store A \| \| grows +-----------------+ \| down \| Host \| \| +-----------------+ \| \| Wasm in store B \| V +-----------------+ Trying to walk this stack would previously result in a runtime panic. The solution is to push the maintenance of our list of saved Wasm FP/SP/PC registers that allow us to identify contiguous regions of Wasm frames on the stack deeper into `CallThreadState`. The saved registers list is now maintained whenever updating the `CallThreadState` linked list by making the `CallThreadState::prev` field private and only accessible via a getter and setter, where the setter always maintains our invariants.	2 years ago
Benjamin Bouvier	a40b253792	Uncomment unwind stack frame tests that now pass on aarch64 (#4687 ) Thanks to #4431 and @fitzgen who implemented it!	2 years ago
Nick Fitzgerald	ec47335b9c	wasmtime: Add a `Config::native_unwind_info` method (#4643 ) This method configures whether native unwind information (e.g. `.eh_frame` on Linux) is generated or not. This helps integrate with third-party stack capturing tools, such as the system unwinder or the `backtrace` crate. It does not affect whether Wasmtime can capture stack traces in Wasm code that it is running or not. Unwind info is always enabled on Windows, since the Windows ABI requires it. This configuration option defaults to true. Additionally, we deprecate `Config::wasm_backtrace` since we can always cheaply capture stack traces ever since https://github.com/bytecodealliance/wasmtime/pull/4431. Fixes https://github.com/bytecodealliance/wasmtime/issues/4554	2 years ago
Nick Fitzgerald	46782b18c2	`wasmtime`: Implement fast Wasm stack walking (#4431 ) * Always preserve frame pointers in Wasmtime This allows us to efficiently and simply capture Wasm stacks without maintaining and synchronizing any safety-critical side tables between the compiler and the runtime. * wasmtime: Implement fast Wasm stack walking Why do we want Wasm stack walking to be fast? Because we capture stacks whenever there is a trap and traps actually happen fairly frequently with short-lived programs and WASI's `exit`. Previously, we would rely on generating the system unwind info (e.g. `.eh_frame`) and using the system unwinder (via the `backtrace`crate) to walk the full stack and filter out any non-Wasm stack frames. This can, unfortunately, be slow for two primary reasons: 1. The system unwinder is doing `O(all-kinds-of-frames)` work rather than `O(wasm-frames)` work. 2. System unwind info and the system unwinder need to be much more general than a purpose-built stack walker for Wasm needs to be. It has to handle any kind of stack frame that any compiler might emit where as our Wasm frames are emitted by Cranelift and always have frame pointers. This translates into implementation complexity and general overhead. There can also be unnecessary-for-our-use-cases global synchronization and locks involved, further slowing down stack walking in the presence of multiple threads trying to capture stacks in parallel. This commit introduces a purpose-built stack walker for traversing just our Wasm frames. To find all the sequences of Wasm-to-Wasm stack frames, and ignore non-Wasm stack frames, we keep a linked list of `(entry stack pointer, exit frame pointer)` pairs. This linked list is maintained via Wasm-to-host and host-to-Wasm trampolines. Within a sequence of Wasm-to-Wasm calls, we can use frame pointers (which Cranelift preserves) to find the next older Wasm frame on the stack, and we keep doing this until we reach the entry stack pointer, meaning that the next older frame will be a host frame. The trampolines need to avoid a couple stumbling blocks. First, they need to be compiled ahead of time, since we may not have access to a compiler at runtime (e.g. if the `cranelift` feature is disabled) but still want to be able to call functions that have already been compiled and get stack traces for those functions. Usually this means we would compile the appropriate trampolines inside `Module::new` and the compiled module object would hold the trampolines. However, we also need to support calling host functions that are wrapped into `wasmtime::Func`s and there doesn't exist any ahead-of-time compiled module object to hold the appropriate trampolines: ```rust // Define a host function. let func_type = wasmtime::FuncType::new( vec![wasmtime::ValType::I32], vec![wasmtime::ValType::I32], ); let func = Func::new(&mut store, func_type, \|_, params, results\| { // ... Ok(()) }); // Call that host function. let mut results = vec![wasmtime::Val::I32(0)]; func.call(&[wasmtime::Val::I32(0)], &mut results)?; ``` Therefore, we define one host-to-Wasm trampoline and one Wasm-to-host trampoline in assembly that work for all Wasm and host function signatures. These trampolines are careful to only use volatile registers, avoid touching any register that is an argument in the calling convention ABI, and tail call to the target callee function. This allows forwarding any set of arguments and any returns to and from the callee, while also allowing us to maintain our linked list of Wasm stack and frame pointers before transferring control to the callee. These trampolines are not used in Wasm-to-Wasm calls, only when crossing the host-Wasm boundary, so they do not impose overhead on regular calls. (And if using one trampoline for all host-Wasm boundary crossing ever breaks branch prediction enough in the CPU to become any kind of bottleneck, we can do fun things like have multiple copies of the same trampoline and choose a random copy for each function, sharding the functions across branch predictor entries.) Finally, this commit also ends the use of a synthetic `Module` and allocating a stubbed out `VMContext` for host functions. Instead, we define a `VMHostFuncContext` with its own magic value, similar to `VMComponentContext`, specifically for host functions. <h2>Benchmarks</h2> <h3>Traps and Stack Traces</h3> Large improvements to taking stack traces on traps, ranging from shaving off 64% to 99.95% of the time it used to take. <details> ``` multi-threaded-traps/0 time: [2.5686 us 2.5808 us 2.5934 us] thrpt: [0.0000 elem/s 0.0000 elem/s 0.0000 elem/s] change: time: [-85.419% -85.153% -84.869%] (p = 0.00 < 0.05) thrpt: [+560.90% +573.56% +585.84%] Performance has improved. Found 8 outliers among 100 measurements (8.00%) 4 (4.00%) high mild 4 (4.00%) high severe multi-threaded-traps/1 time: [2.9021 us 2.9167 us 2.9322 us] thrpt: [341.04 Kelem/s 342.86 Kelem/s 344.58 Kelem/s] change: time: [-91.455% -91.294% -91.096%] (p = 0.00 < 0.05) thrpt: [+1023.1% +1048.6% +1070.3%] Performance has improved. Found 6 outliers among 100 measurements (6.00%) 1 (1.00%) high mild 5 (5.00%) high severe multi-threaded-traps/2 time: [2.9996 us 3.0145 us 3.0295 us] thrpt: [660.18 Kelem/s 663.47 Kelem/s 666.76 Kelem/s] change: time: [-94.040% -93.910% -93.762%] (p = 0.00 < 0.05) thrpt: [+1503.1% +1542.0% +1578.0%] Performance has improved. Found 5 outliers among 100 measurements (5.00%) 5 (5.00%) high severe multi-threaded-traps/4 time: [5.5768 us 5.6052 us 5.6364 us] thrpt: [709.68 Kelem/s 713.63 Kelem/s 717.25 Kelem/s] change: time: [-93.193% -93.121% -93.052%] (p = 0.00 < 0.05) thrpt: [+1339.2% +1353.6% +1369.1%] Performance has improved. multi-threaded-traps/8 time: [8.6408 us 9.1212 us 9.5438 us] thrpt: [838.24 Kelem/s 877.08 Kelem/s 925.84 Kelem/s] change: time: [-94.754% -94.473% -94.202%] (p = 0.00 < 0.05) thrpt: [+1624.7% +1709.2% +1806.1%] Performance has improved. multi-threaded-traps/16 time: [10.152 us 10.840 us 11.545 us] thrpt: [1.3858 Melem/s 1.4760 Melem/s 1.5761 Melem/s] change: time: [-97.042% -96.823% -96.577%] (p = 0.00 < 0.05) thrpt: [+2821.5% +3048.1% +3281.1%] Performance has improved. Found 1 outliers among 100 measurements (1.00%) 1 (1.00%) high mild many-modules-registered-traps/1 time: [2.6278 us 2.6361 us 2.6447 us] thrpt: [378.11 Kelem/s 379.35 Kelem/s 380.55 Kelem/s] change: time: [-85.311% -85.108% -84.909%] (p = 0.00 < 0.05) thrpt: [+562.65% +571.51% +580.76%] Performance has improved. Found 9 outliers among 100 measurements (9.00%) 3 (3.00%) high mild 6 (6.00%) high severe many-modules-registered-traps/8 time: [2.6294 us 2.6460 us 2.6623 us] thrpt: [3.0049 Melem/s 3.0235 Melem/s 3.0425 Melem/s] change: time: [-85.895% -85.485% -85.022%] (p = 0.00 < 0.05) thrpt: [+567.63% +588.95% +608.95%] Performance has improved. Found 8 outliers among 100 measurements (8.00%) 3 (3.00%) high mild 5 (5.00%) high severe many-modules-registered-traps/64 time: [2.6218 us 2.6329 us 2.6452 us] thrpt: [24.195 Melem/s 24.308 Melem/s 24.411 Melem/s] change: time: [-93.629% -93.551% -93.470%] (p = 0.00 < 0.05) thrpt: [+1431.4% +1450.6% +1469.5%] Performance has improved. Found 3 outliers among 100 measurements (3.00%) 3 (3.00%) high mild many-modules-registered-traps/512 time: [2.6569 us 2.6737 us 2.6923 us] thrpt: [190.17 Melem/s 191.50 Melem/s 192.71 Melem/s] change: time: [-99.277% -99.268% -99.260%] (p = 0.00 < 0.05) thrpt: [+13417% +13566% +13731%] Performance has improved. Found 4 outliers among 100 measurements (4.00%) 4 (4.00%) high mild many-modules-registered-traps/4096 time: [2.7258 us 2.7390 us 2.7535 us] thrpt: [1.4876 Gelem/s 1.4955 Gelem/s 1.5027 Gelem/s] change: time: [-99.956% -99.955% -99.955%] (p = 0.00 < 0.05) thrpt: [+221417% +223380% +224881%] Performance has improved. Found 2 outliers among 100 measurements (2.00%) 1 (1.00%) high mild 1 (1.00%) high severe many-stack-frames-traps/1 time: [1.4658 us 1.4719 us 1.4784 us] thrpt: [676.39 Kelem/s 679.38 Kelem/s 682.21 Kelem/s] change: time: [-90.368% -89.947% -89.586%] (p = 0.00 < 0.05) thrpt: [+860.23% +894.72% +938.21%] Performance has improved. Found 8 outliers among 100 measurements (8.00%) 5 (5.00%) high mild 3 (3.00%) high severe many-stack-frames-traps/8 time: [2.4772 us 2.4870 us 2.4973 us] thrpt: [3.2034 Melem/s 3.2167 Melem/s 3.2294 Melem/s] change: time: [-85.550% -85.370% -85.199%] (p = 0.00 < 0.05) thrpt: [+575.65% +583.51% +592.03%] Performance has improved. Found 8 outliers among 100 measurements (8.00%) 4 (4.00%) high mild 4 (4.00%) high severe many-stack-frames-traps/64 time: [10.109 us 10.171 us 10.236 us] thrpt: [6.2525 Melem/s 6.2925 Melem/s 6.3309 Melem/s] change: time: [-78.144% -77.797% -77.336%] (p = 0.00 < 0.05) thrpt: [+341.22% +350.38% +357.55%] Performance has improved. Found 7 outliers among 100 measurements (7.00%) 5 (5.00%) high mild 2 (2.00%) high severe many-stack-frames-traps/512 time: [126.16 us 126.54 us 126.96 us] thrpt: [4.0329 Melem/s 4.0461 Melem/s 4.0583 Melem/s] change: time: [-65.364% -64.933% -64.453%] (p = 0.00 < 0.05) thrpt: [+181.32% +185.17% +188.71%] Performance has improved. Found 4 outliers among 100 measurements (4.00%) 4 (4.00%) high severe ``` </details> <h3>Calls</h3> There is, however, a small regression in raw Wasm-to-host and host-to-Wasm call performance due the new trampolines. It seems to be on the order of about 2-10 nanoseconds per call, depending on the benchmark. I believe this regression is ultimately acceptable because 1. this overhead will be vastly dominated by whatever work a non-nop callee actually does, 2. we will need these trampolines, or something like them, when implementing the Wasm exceptions proposal to do things like translate Wasm's exceptions into Rust's `Result`s, 3. and because the performance improvements to trapping and capturing stack traces are of such a larger magnitude than this call regressions. <details> ``` sync/no-hook/host-to-wasm - typed - nop time: [28.683 ns 28.757 ns 28.844 ns] change: [+16.472% +17.183% +17.904%] (p = 0.00 < 0.05) Performance has regressed. Found 10 outliers among 100 measurements (10.00%) 1 (1.00%) low mild 4 (4.00%) high mild 5 (5.00%) high severe sync/no-hook/host-to-wasm - untyped - nop time: [42.515 ns 42.652 ns 42.841 ns] change: [+12.371% +14.614% +17.462%] (p = 0.00 < 0.05) Performance has regressed. Found 11 outliers among 100 measurements (11.00%) 1 (1.00%) high mild 10 (10.00%) high severe sync/no-hook/host-to-wasm - unchecked - nop time: [33.936 ns 34.052 ns 34.179 ns] change: [+25.478% +26.938% +28.369%] (p = 0.00 < 0.05) Performance has regressed. Found 9 outliers among 100 measurements (9.00%) 7 (7.00%) high mild 2 (2.00%) high severe sync/no-hook/host-to-wasm - typed - nop-params-and-results time: [34.290 ns 34.388 ns 34.502 ns] change: [+40.802% +42.706% +44.526%] (p = 0.00 < 0.05) Performance has regressed. Found 13 outliers among 100 measurements (13.00%) 5 (5.00%) high mild 8 (8.00%) high severe sync/no-hook/host-to-wasm - untyped - nop-params-and-results time: [62.546 ns 62.721 ns 62.919 ns] change: [+2.5014% +3.6319% +4.8078%] (p = 0.00 < 0.05) Performance has regressed. Found 12 outliers among 100 measurements (12.00%) 2 (2.00%) high mild 10 (10.00%) high severe sync/no-hook/host-to-wasm - unchecked - nop-params-and-results time: [42.609 ns 42.710 ns 42.831 ns] change: [+20.966% +22.282% +23.475%] (p = 0.00 < 0.05) Performance has regressed. Found 11 outliers among 100 measurements (11.00%) 4 (4.00%) high mild 7 (7.00%) high severe sync/hook-sync/host-to-wasm - typed - nop time: [29.546 ns 29.675 ns 29.818 ns] change: [+20.693% +21.794% +22.836%] (p = 0.00 < 0.05) Performance has regressed. Found 5 outliers among 100 measurements (5.00%) 3 (3.00%) high mild 2 (2.00%) high severe sync/hook-sync/host-to-wasm - untyped - nop time: [45.448 ns 45.699 ns 45.961 ns] change: [+17.204% +18.514% +19.590%] (p = 0.00 < 0.05) Performance has regressed. Found 14 outliers among 100 measurements (14.00%) 4 (4.00%) high mild 10 (10.00%) high severe sync/hook-sync/host-to-wasm - unchecked - nop time: [34.334 ns 34.437 ns 34.558 ns] change: [+23.225% +24.477% +25.886%] (p = 0.00 < 0.05) Performance has regressed. Found 12 outliers among 100 measurements (12.00%) 5 (5.00%) high mild 7 (7.00%) high severe sync/hook-sync/host-to-wasm - typed - nop-params-and-results time: [36.594 ns 36.763 ns 36.974 ns] change: [+41.967% +47.261% +52.086%] (p = 0.00 < 0.05) Performance has regressed. Found 12 outliers among 100 measurements (12.00%) 3 (3.00%) high mild 9 (9.00%) high severe sync/hook-sync/host-to-wasm - untyped - nop-params-and-results time: [63.541 ns 63.831 ns 64.194 ns] change: [-4.4337% -0.6855% +2.7134%] (p = 0.73 > 0.05) No change in performance detected. Found 8 outliers among 100 measurements (8.00%) 6 (6.00%) high mild 2 (2.00%) high severe sync/hook-sync/host-to-wasm - unchecked - nop-params-and-results time: [43.968 ns 44.169 ns 44.437 ns] change: [+18.772% +21.802% +24.623%] (p = 0.00 < 0.05) Performance has regressed. Found 15 outliers among 100 measurements (15.00%) 3 (3.00%) high mild 12 (12.00%) high severe async/no-hook/host-to-wasm - typed - nop time: [4.9612 us 4.9743 us 4.9889 us] change: [+9.9493% +11.911% +13.502%] (p = 0.00 < 0.05) Performance has regressed. Found 10 outliers among 100 measurements (10.00%) 6 (6.00%) high mild 4 (4.00%) high severe async/no-hook/host-to-wasm - untyped - nop time: [5.0030 us 5.0211 us 5.0439 us] change: [+10.841% +11.873% +12.977%] (p = 0.00 < 0.05) Performance has regressed. Found 10 outliers among 100 measurements (10.00%) 3 (3.00%) high mild 7 (7.00%) high severe async/no-hook/host-to-wasm - typed - nop-params-and-results time: [4.9273 us 4.9468 us 4.9700 us] change: [+4.7381% +6.8445% +8.8238%] (p = 0.00 < 0.05) Performance has regressed. Found 14 outliers among 100 measurements (14.00%) 5 (5.00%) high mild 9 (9.00%) high severe async/no-hook/host-to-wasm - untyped - nop-params-and-results time: [5.1151 us 5.1338 us 5.1555 us] change: [+9.5335% +11.290% +13.044%] (p = 0.00 < 0.05) Performance has regressed. Found 16 outliers among 100 measurements (16.00%) 3 (3.00%) high mild 13 (13.00%) high severe async/hook-sync/host-to-wasm - typed - nop time: [4.9330 us 4.9394 us 4.9467 us] change: [+10.046% +11.038% +12.035%] (p = 0.00 < 0.05) Performance has regressed. Found 12 outliers among 100 measurements (12.00%) 5 (5.00%) high mild 7 (7.00%) high severe async/hook-sync/host-to-wasm - untyped - nop time: [5.0073 us 5.0183 us 5.0310 us] change: [+9.3828% +10.565% +11.752%] (p = 0.00 < 0.05) Performance has regressed. Found 8 outliers among 100 measurements (8.00%) 3 (3.00%) high mild 5 (5.00%) high severe async/hook-sync/host-to-wasm - typed - nop-params-and-results time: [4.9610 us 4.9839 us 5.0097 us] change: [+9.0857% +11.513% +14.359%] (p = 0.00 < 0.05) Performance has regressed. Found 13 outliers among 100 measurements (13.00%) 7 (7.00%) high mild 6 (6.00%) high severe async/hook-sync/host-to-wasm - untyped - nop-params-and-results time: [5.0995 us 5.1272 us 5.1617 us] change: [+9.3600% +11.506% +13.809%] (p = 0.00 < 0.05) Performance has regressed. Found 10 outliers among 100 measurements (10.00%) 6 (6.00%) high mild 4 (4.00%) high severe async-pool/no-hook/host-to-wasm - typed - nop time: [2.4242 us 2.4316 us 2.4396 us] change: [+7.8756% +8.8803% +9.8346%] (p = 0.00 < 0.05) Performance has regressed. Found 8 outliers among 100 measurements (8.00%) 5 (5.00%) high mild 3 (3.00%) high severe async-pool/no-hook/host-to-wasm - untyped - nop time: [2.5102 us 2.5155 us 2.5210 us] change: [+12.130% +13.194% +14.270%] (p = 0.00 < 0.05) Performance has regressed. Found 12 outliers among 100 measurements (12.00%) 4 (4.00%) high mild 8 (8.00%) high severe async-pool/no-hook/host-to-wasm - typed - nop-params-and-results time: [2.4203 us 2.4310 us 2.4440 us] change: [+4.0380% +6.3623% +8.7534%] (p = 0.00 < 0.05) Performance has regressed. Found 14 outliers among 100 measurements (14.00%) 5 (5.00%) high mild 9 (9.00%) high severe async-pool/no-hook/host-to-wasm - untyped - nop-params-and-results time: [2.5501 us 2.5593 us 2.5700 us] change: [+8.8802% +10.976% +12.937%] (p = 0.00 < 0.05) Performance has regressed. Found 16 outliers among 100 measurements (16.00%) 5 (5.00%) high mild 11 (11.00%) high severe async-pool/hook-sync/host-to-wasm - typed - nop time: [2.4135 us 2.4190 us 2.4254 us] change: [+8.3640% +9.3774% +10.435%] (p = 0.00 < 0.05) Performance has regressed. Found 11 outliers among 100 measurements (11.00%) 6 (6.00%) high mild 5 (5.00%) high severe async-pool/hook-sync/host-to-wasm - untyped - nop time: [2.5172 us 2.5248 us 2.5357 us] change: [+11.543% +12.750% +13.982%] (p = 0.00 < 0.05) Performance has regressed. Found 8 outliers among 100 measurements (8.00%) 1 (1.00%) high mild 7 (7.00%) high severe async-pool/hook-sync/host-to-wasm - typed - nop-params-and-results time: [2.4214 us 2.4353 us 2.4532 us] change: [+1.5158% +5.0872% +8.6765%] (p = 0.00 < 0.05) Performance has regressed. Found 15 outliers among 100 measurements (15.00%) 2 (2.00%) high mild 13 (13.00%) high severe async-pool/hook-sync/host-to-wasm - untyped - nop-params-and-results time: [2.5499 us 2.5607 us 2.5748 us] change: [+10.146% +12.459% +14.919%] (p = 0.00 < 0.05) Performance has regressed. Found 18 outliers among 100 measurements (18.00%) 3 (3.00%) high mild 15 (15.00%) high severe sync/no-hook/wasm-to-host - nop - typed time: [6.6135 ns 6.6288 ns 6.6452 ns] change: [+37.927% +38.837% +39.869%] (p = 0.00 < 0.05) Performance has regressed. Found 7 outliers among 100 measurements (7.00%) 2 (2.00%) high mild 5 (5.00%) high severe sync/no-hook/wasm-to-host - nop-params-and-results - typed time: [15.930 ns 15.993 ns 16.067 ns] change: [+3.9583% +5.6286% +7.2430%] (p = 0.00 < 0.05) Performance has regressed. Found 12 outliers among 100 measurements (12.00%) 11 (11.00%) high mild 1 (1.00%) high severe sync/no-hook/wasm-to-host - nop - untyped time: [20.596 ns 20.640 ns 20.690 ns] change: [+4.3293% +5.2047% +6.0935%] (p = 0.00 < 0.05) Performance has regressed. Found 10 outliers among 100 measurements (10.00%) 5 (5.00%) high mild 5 (5.00%) high severe sync/no-hook/wasm-to-host - nop-params-and-results - untyped time: [42.659 ns 42.882 ns 43.159 ns] change: [-2.1466% -0.5079% +1.2554%] (p = 0.58 > 0.05) No change in performance detected. Found 15 outliers among 100 measurements (15.00%) 1 (1.00%) high mild 14 (14.00%) high severe sync/no-hook/wasm-to-host - nop - unchecked time: [10.671 ns 10.691 ns 10.713 ns] change: [+83.911% +87.620% +92.062%] (p = 0.00 < 0.05) Performance has regressed. Found 9 outliers among 100 measurements (9.00%) 2 (2.00%) high mild 7 (7.00%) high severe sync/no-hook/wasm-to-host - nop-params-and-results - unchecked time: [11.136 ns 11.190 ns 11.263 ns] change: [-29.719% -28.446% -27.029%] (p = 0.00 < 0.05) Performance has improved. Found 14 outliers among 100 measurements (14.00%) 4 (4.00%) high mild 10 (10.00%) high severe sync/hook-sync/wasm-to-host - nop - typed time: [6.7964 ns 6.8087 ns 6.8226 ns] change: [+21.531% +24.206% +27.331%] (p = 0.00 < 0.05) Performance has regressed. Found 14 outliers among 100 measurements (14.00%) 4 (4.00%) high mild 10 (10.00%) high severe sync/hook-sync/wasm-to-host - nop-params-and-results - typed time: [15.865 ns 15.921 ns 15.985 ns] change: [+4.8466% +6.3330% +7.8317%] (p = 0.00 < 0.05) Performance has regressed. Found 16 outliers among 100 measurements (16.00%) 3 (3.00%) high mild 13 (13.00%) high severe sync/hook-sync/wasm-to-host - nop - untyped time: [21.505 ns 21.587 ns 21.677 ns] change: [+8.0908% +9.1943% +10.254%] (p = 0.00 < 0.05) Performance has regressed. Found 8 outliers among 100 measurements (8.00%) 4 (4.00%) high mild 4 (4.00%) high severe sync/hook-sync/wasm-to-host - nop-params-and-results - untyped time: [44.018 ns 44.128 ns 44.261 ns] change: [-1.4671% -0.0458% +1.2443%] (p = 0.94 > 0.05) No change in performance detected. Found 14 outliers among 100 measurements (14.00%) 5 (5.00%) high mild 9 (9.00%) high severe sync/hook-sync/wasm-to-host - nop - unchecked time: [11.264 ns 11.326 ns 11.387 ns] change: [+80.225% +81.659% +83.068%] (p = 0.00 < 0.05) Performance has regressed. Found 6 outliers among 100 measurements (6.00%) 3 (3.00%) high mild 3 (3.00%) high severe sync/hook-sync/wasm-to-host - nop-params-and-results - unchecked time: [11.816 ns 11.865 ns 11.920 ns] change: [-29.152% -28.040% -26.957%] (p = 0.00 < 0.05) Performance has improved. Found 14 outliers among 100 measurements (14.00%) 8 (8.00%) high mild 6 (6.00%) high severe async/no-hook/wasm-to-host - nop - typed time: [6.6221 ns 6.6385 ns 6.6569 ns] change: [+43.618% +44.755% +45.965%] (p = 0.00 < 0.05) Performance has regressed. Found 13 outliers among 100 measurements (13.00%) 6 (6.00%) high mild 7 (7.00%) high severe async/no-hook/wasm-to-host - nop-params-and-results - typed time: [15.884 ns 15.929 ns 15.983 ns] change: [+3.5987% +5.2053% +6.7846%] (p = 0.00 < 0.05) Performance has regressed. Found 16 outliers among 100 measurements (16.00%) 3 (3.00%) high mild 13 (13.00%) high severe async/no-hook/wasm-to-host - nop - untyped time: [20.615 ns 20.702 ns 20.821 ns] change: [+6.9799% +8.1212% +9.2819%] (p = 0.00 < 0.05) Performance has regressed. Found 10 outliers among 100 measurements (10.00%) 2 (2.00%) high mild 8 (8.00%) high severe async/no-hook/wasm-to-host - nop-params-and-results - untyped time: [41.956 ns 42.207 ns 42.521 ns] change: [-4.3057% -2.7730% -1.2428%] (p = 0.00 < 0.05) Performance has improved. Found 14 outliers among 100 measurements (14.00%) 3 (3.00%) high mild 11 (11.00%) high severe async/no-hook/wasm-to-host - nop - unchecked time: [10.440 ns 10.474 ns 10.513 ns] change: [+83.959% +85.826% +87.541%] (p = 0.00 < 0.05) Performance has regressed. Found 11 outliers among 100 measurements (11.00%) 5 (5.00%) high mild 6 (6.00%) high severe async/no-hook/wasm-to-host - nop-params-and-results - unchecked time: [11.476 ns 11.512 ns 11.554 ns] change: [-29.857% -28.383% -26.978%] (p = 0.00 < 0.05) Performance has improved. Found 12 outliers among 100 measurements (12.00%) 1 (1.00%) low mild 6 (6.00%) high mild 5 (5.00%) high severe async/no-hook/wasm-to-host - nop - async-typed time: [26.427 ns 26.478 ns 26.532 ns] change: [+6.5730% +7.4676% +8.3983%] (p = 0.00 < 0.05) Performance has regressed. Found 9 outliers among 100 measurements (9.00%) 2 (2.00%) high mild 7 (7.00%) high severe async/no-hook/wasm-to-host - nop-params-and-results - async-typed time: [28.557 ns 28.693 ns 28.880 ns] change: [+1.9099% +3.7332% +5.9731%] (p = 0.00 < 0.05) Performance has regressed. Found 15 outliers among 100 measurements (15.00%) 1 (1.00%) high mild 14 (14.00%) high severe async/hook-sync/wasm-to-host - nop - typed time: [6.7488 ns 6.7630 ns 6.7784 ns] change: [+19.935% +22.080% +23.683%] (p = 0.00 < 0.05) Performance has regressed. Found 9 outliers among 100 measurements (9.00%) 4 (4.00%) high mild 5 (5.00%) high severe async/hook-sync/wasm-to-host - nop-params-and-results - typed time: [15.928 ns 16.031 ns 16.149 ns] change: [+5.5188% +6.9567% +8.3839%] (p = 0.00 < 0.05) Performance has regressed. Found 11 outliers among 100 measurements (11.00%) 9 (9.00%) high mild 2 (2.00%) high severe async/hook-sync/wasm-to-host - nop - untyped time: [21.930 ns 22.114 ns 22.296 ns] change: [+4.6674% +7.7588% +10.375%] (p = 0.00 < 0.05) Performance has regressed. Found 4 outliers among 100 measurements (4.00%) 3 (3.00%) high mild 1 (1.00%) high severe async/hook-sync/wasm-to-host - nop-params-and-results - untyped time: [42.684 ns 42.858 ns 43.081 ns] change: [-5.2957% -3.4693% -1.6217%] (p = 0.00 < 0.05) Performance has improved. Found 14 outliers among 100 measurements (14.00%) 2 (2.00%) high mild 12 (12.00%) high severe async/hook-sync/wasm-to-host - nop - unchecked time: [11.026 ns 11.053 ns 11.086 ns] change: [+70.751% +72.378% +73.961%] (p = 0.00 < 0.05) Performance has regressed. Found 10 outliers among 100 measurements (10.00%) 5 (5.00%) high mild 5 (5.00%) high severe async/hook-sync/wasm-to-host - nop-params-and-results - unchecked time: [11.840 ns 11.900 ns 11.982 ns] change: [-27.977% -26.584% -24.887%] (p = 0.00 < 0.05) Performance has improved. Found 18 outliers among 100 measurements (18.00%) 3 (3.00%) high mild 15 (15.00%) high severe async/hook-sync/wasm-to-host - nop - async-typed time: [27.601 ns 27.709 ns 27.882 ns] change: [+8.1781% +9.1102% +10.030%] (p = 0.00 < 0.05) Performance has regressed. Found 11 outliers among 100 measurements (11.00%) 2 (2.00%) low mild 3 (3.00%) high mild 6 (6.00%) high severe async/hook-sync/wasm-to-host - nop-params-and-results - async-typed time: [28.955 ns 29.174 ns 29.413 ns] change: [+1.1226% +3.0366% +5.1126%] (p = 0.00 < 0.05) Performance has regressed. Found 13 outliers among 100 measurements (13.00%) 7 (7.00%) high mild 6 (6.00%) high severe async-pool/no-hook/wasm-to-host - nop - typed time: [6.5626 ns 6.5733 ns 6.5851 ns] change: [+40.561% +42.307% +44.514%] (p = 0.00 < 0.05) Performance has regressed. Found 9 outliers among 100 measurements (9.00%) 5 (5.00%) high mild 4 (4.00%) high severe async-pool/no-hook/wasm-to-host - nop-params-and-results - typed time: [15.820 ns 15.886 ns 15.969 ns] change: [+4.1044% +5.7928% +7.7122%] (p = 0.00 < 0.05) Performance has regressed. Found 17 outliers among 100 measurements (17.00%) 4 (4.00%) high mild 13 (13.00%) high severe async-pool/no-hook/wasm-to-host - nop - untyped time: [20.481 ns 20.521 ns 20.566 ns] change: [+6.7962% +7.6950% +8.7612%] (p = 0.00 < 0.05) Performance has regressed. Found 11 outliers among 100 measurements (11.00%) 6 (6.00%) high mild 5 (5.00%) high severe async-pool/no-hook/wasm-to-host - nop-params-and-results - untyped time: [41.834 ns 41.998 ns 42.189 ns] change: [-3.8185% -2.2687% -0.7541%] (p = 0.01 < 0.05) Change within noise threshold. Found 13 outliers among 100 measurements (13.00%) 3 (3.00%) high mild 10 (10.00%) high severe async-pool/no-hook/wasm-to-host - nop - unchecked time: [10.353 ns 10.380 ns 10.414 ns] change: [+82.042% +84.591% +87.205%] (p = 0.00 < 0.05) Performance has regressed. Found 7 outliers among 100 measurements (7.00%) 4 (4.00%) high mild 3 (3.00%) high severe async-pool/no-hook/wasm-to-host - nop-params-and-results - unchecked time: [11.123 ns 11.168 ns 11.228 ns] change: [-30.813% -29.285% -27.874%] (p = 0.00 < 0.05) Performance has improved. Found 12 outliers among 100 measurements (12.00%) 11 (11.00%) high mild 1 (1.00%) high severe async-pool/no-hook/wasm-to-host - nop - async-typed time: [27.442 ns 27.528 ns 27.638 ns] change: [+7.5215% +9.9795% +12.266%] (p = 0.00 < 0.05) Performance has regressed. Found 18 outliers among 100 measurements (18.00%) 3 (3.00%) high mild 15 (15.00%) high severe async-pool/no-hook/wasm-to-host - nop-params-and-results - async-typed time: [29.014 ns 29.148 ns 29.312 ns] change: [+2.0227% +3.4722% +4.9047%] (p = 0.00 < 0.05) Performance has regressed. Found 7 outliers among 100 measurements (7.00%) 6 (6.00%) high mild 1 (1.00%) high severe async-pool/hook-sync/wasm-to-host - nop - typed time: [6.7916 ns 6.8116 ns 6.8325 ns] change: [+20.937% +22.050% +23.281%] (p = 0.00 < 0.05) Performance has regressed. Found 11 outliers among 100 measurements (11.00%) 5 (5.00%) high mild 6 (6.00%) high severe async-pool/hook-sync/wasm-to-host - nop-params-and-results - typed time: [15.917 ns 15.975 ns 16.051 ns] change: [+4.6404% +6.4217% +8.3075%] (p = 0.00 < 0.05) Performance has regressed. Found 16 outliers among 100 measurements (16.00%) 5 (5.00%) high mild 11 (11.00%) high severe async-pool/hook-sync/wasm-to-host - nop - untyped time: [21.558 ns 21.612 ns 21.679 ns] change: [+8.1158% +9.1409% +10.217%] (p = 0.00 < 0.05) Performance has regressed. Found 9 outliers among 100 measurements (9.00%) 2 (2.00%) high mild 7 (7.00%) high severe async-pool/hook-sync/wasm-to-host - nop-params-and-results - untyped time: [42.475 ns 42.614 ns 42.775 ns] change: [-6.3613% -4.4709% -2.7647%] (p = 0.00 < 0.05) Performance has improved. Found 18 outliers among 100 measurements (18.00%) 3 (3.00%) high mild 15 (15.00%) high severe async-pool/hook-sync/wasm-to-host - nop - unchecked time: [11.150 ns 11.195 ns 11.247 ns] change: [+74.424% +77.056% +79.811%] (p = 0.00 < 0.05) Performance has regressed. Found 14 outliers among 100 measurements (14.00%) 3 (3.00%) high mild 11 (11.00%) high severe async-pool/hook-sync/wasm-to-host - nop-params-and-results - unchecked time: [11.639 ns 11.695 ns 11.760 ns] change: [-30.212% -29.023% -27.954%] (p = 0.00 < 0.05) Performance has improved. Found 15 outliers among 100 measurements (15.00%) 7 (7.00%) high mild 8 (8.00%) high severe async-pool/hook-sync/wasm-to-host - nop - async-typed time: [27.480 ns 27.712 ns 27.984 ns] change: [+2.9764% +6.5061% +9.8914%] (p = 0.00 < 0.05) Performance has regressed. Found 8 outliers among 100 measurements (8.00%) 6 (6.00%) high mild 2 (2.00%) high severe async-pool/hook-sync/wasm-to-host - nop-params-and-results - async-typed time: [29.218 ns 29.380 ns 29.600 ns] change: [+5.2283% +7.7247% +10.822%] (p = 0.00 < 0.05) Performance has regressed. Found 16 outliers among 100 measurements (16.00%) 2 (2.00%) high mild 14 (14.00%) high severe ``` </details> * Add s390x support for frame pointer-based stack walking * wasmtime: Allow `Caller::get_export` to get all exports * fuzzing: Add a fuzz target to check that our stack traces are correct We generate Wasm modules that keep track of their own stack as they call and return between functions, and then we periodically check that if the host captures a backtrace, it matches what the Wasm module has recorded. * Remove VM offsets for `VMHostFuncContext` since it isn't used by JIT code * Add doc comment with stack walking implementation notes * Document the extra state that can be passed to `wasmtime_runtime::Backtrace` methods * Add extensive comments for stack walking function * Factor architecture-specific bits of stack walking out into modules * Initialize store-related fields in a vmctx to null when there is no store yet Rather than leaving them as uninitialized data. * Use `set_callee` instead of manually setting the vmctx field * Use a more informative compile error message for unsupported architectures * Document unsafety of `prepare_host_to_wasm_trampoline` * Use `bti c` instead of `hint #34` in inline aarch64 assembly * Remove outdated TODO comment * Remove setting of `last_wasm_exit_fp` in `set_jit_trap` This is no longer needed as the value is plumbed through to the backtrace code directly now. * Only set the stack limit once, in the face of re-entrancy into Wasm * Add comments for s390x-specific stack walking bits * Use the helper macro for all libcalls If we forget to use it, and then trigger a GC from the libcall, that means we could miss stack frames when walking the stack, fail to find live GC refs, and then get use after free bugs. Much less risky to always use the helper macro that takes care of all of that for us. * Use the `asm_sym!` macro in Wasm-to-libcall trampolines This macro handles the macOS-specific underscore prefix stuff for us. * wasmtime: add size and align to `externref` assertion error message * Extend the `stacks` fuzzer to have host frames in between Wasm frames This way we get one or more contiguous sequences of Wasm frames on the stack, instead of exactly one. * Add documentation for aarch64-specific backtrace helpers * Clarify that we only support little-endian aarch64 in trampoline comment * Use `.machine z13` in s390x assembly file Since apparently our CI machines have pretty old assemblers that don't have `.machine z14`. This should be fine though since these trampolines don't make use of anything that is introduced in z14. * Fix aarch64 build * Fix macOS build * Document the `asm_sym!` macro * Add windows support to the `wasmtime-asm-macros` crate * Add windows support to host<--->Wasm trampolines * Fix trap handler build on windows * Run `rustfmt` on s390x trampoline source file * Temporarily disable some assertions about a trap's backtrace in the component model tests Follow up to re-enable this and fix the associated issue: https://github.com/bytecodealliance/wasmtime/issues/4535 * Refactor libcall definitions with less macros This refactors the `libcall!` macro to use the `foreach_builtin_function!` macro to define all of the trampolines. Additionally the macro surrounding each libcall itself is no longer necessary and helps avoid too many macros. * Use `VMOpaqueContext::from_vm_host_func_context` in `VMHostFuncContext::new` * Move `backtrace` module to be submodule of `traphandlers` This avoids making some things `pub(crate)` in `traphandlers` that really shouldn't be. * Fix macOS aarch64 build * Use "i64" instead of "word" in aarch64-specific file * Save/restore entry SP and exit FP/return pointer in the face of panicking imported host functions Also clean up assertions surrounding our saved entry/exit registers. * Put "typed" vs "untyped" in the same position of call benchmark names Regardless if we are doing wasm-to-host or host-to-wasm * Fix stacks test case generator build for new `wasm-encoder` * Fix build for s390x * Expand libcalls in s390x asm * Disable more parts of component tests now that backtrace assertions are a bit tighter * Remove assertion that can maybe fail on s390x Co-authored-by: Ulrich Weigand <ulrich.weigand@de.ibm.com> Co-authored-by: Alex Crichton <alex@alexcrichton.com>	2 years ago
Pat Hickey	bffce37050	make backtrace collection a Config field rather than a cargo feature (#4183 ) * sorta working in runtime * wasmtime-runtime: get rid of wasm-backtrace feature * wasmtime: factor to make backtraces recording optional. not configurable yet * get rid of wasm-backtrace features * trap tests: now a Trap optionally contains backtrace * eliminate wasm-backtrace feature * code review fixes * ci: no more wasm-backtrace feature * c_api: backtraces always enabled * config: unwind required by backtraces and ref types * plumbed * test that disabling backtraces works * code review comments * fuzzing generator: wasm_backtrace is a runtime config now * doc fix	2 years ago
Alex Crichton	f1225dfd93	Add a compilation section to disable address maps (#3598 ) * Add a compilation section to disable address maps This commit adds a new `Config::generate_address_map` compilation setting which is used to disable emission of the `.wasmtime.addrmap` section of compiled artifacts. This section is currently around the size of the entire `.text` section itself unfortunately and for size reasons may wish to be omitted. Functionality-wise all that is lost is knowing the precise wasm module offset address of a faulting instruction or in a backtrace of instructions. This also means that if the module has DWARF debugging information available with it Wasmtime isn't able to produce a filename and line number in the backtrace. This option remains enabled by default. This option may not be needed in the future with #3547 perhaps, but in the meantime it seems reasonable enough to support a configuration mode where the section is entirely omitted if the smallest module possible is desired. * Fix some CI issues * Update tests/all/traps.rs Co-authored-by: Nick Fitzgerald <fitzgen@gmail.com> * Do less work in compilation for address maps But only when disabled Co-authored-by: Nick Fitzgerald <fitzgen@gmail.com>	3 years ago
Dan Gohman	42b23dac4a	Make the trap name for `unreachable` traps more descriptive. (#3568 ) Following up on WebAssembly/wasi-sdk#210, this makes the trap message for `unreachable` traps more descriptive of what actually caused the trap, so that it doesn't sound like maybe Wasmtime itself executed a `unreachable!()` macro in Rust. Before: ``` wasm trap: unreachable wasm backtrace: [...] ``` After: ``` wasm trap: wasm `unreachable` instruction executed wasm backtrace: [...] ```	3 years ago
Alex Crichton	bcf3544924	Optimize `Func::call` and its C API (#3319 ) * Optimize `Func::call` and its C API This commit is an alternative to #3298 which achieves effectively the same goal of optimizing the `Func::call` API as well as its C API sibling of `wasmtime_func_call`. The strategy taken here is different than #3298 though where a new API isn't created, rather a small tweak to an existing API is done. Specifically this commit handles the major sources of slowness with `Func::call` with: * Looking up the type of a function, to typecheck the arguments with and use to guide how the results should be loaded, no longer hits the rwlock in the `Engine` but instead each `Func` contains its own `FuncType`. This can be an unnecessary allocation for funcs not used with `Func::call`, so this is a downside of this implementation relative to #3298. A mitigating factor, though, is that instance exports are loaded lazily into the `Store` and in theory not too many funcs are active in the store as `Func` objects. * Temporary storage is amortized with a long-lived `Vec` in the `Store` rather than allocating a new vector on each call. This is basically the same strategy as #3294 only applied to different types in different places. Specifically `wasmtime::Store` now retains a `Vec<u128>` for `Func::call`, and the C API retains a `Vec<Val>` for calling `Func::call`. * Finally, an API breaking change is made to `Func::call` and its type signature (as well as `Func::call_async`). Instead of returning `Box<[Val]>` as it did before this function now takes a `results: &mut [Val]` parameter. This allows the caller to manage the allocation and we can amortize-remove it in `wasmtime_func_call` by using space after the parameters in the `Vec<Val>` we're passing in. This change is naturally a breaking change and we'll want to consider it carefully, but mitigating factors are that most embeddings are likely using `TypedFunc::call` instead and this signature taking a mutable slice better aligns with `Func::new` which receives a mutable slice for the results. Overall this change, in the benchmark of "call a nop function from the C API" is not quite as good as #3298. It's still a bit slower, on the order of 15ns, because there's lots of capacity checks around vectors and the type checks are slightly less optimized than before. Overall though this is still significantly better than today because allocations and the rwlock to acquire the type information are both avoided. I personally feel that this change is the best to do because it has less of an API impact than #3298. * Rebase issues	3 years ago
Alex Crichton	3da677796b	Reword env var hint for dwarf debug info (#3081 ) * Reword env var hint for dwarf debug info Try not to declare that more information will indeed be displayed, instead suggest that the output may improve if the env var is set since dwarf debug info wasn't parsed. cc bytecodealliance/wasmtime-go#90 * Fix test assertion	3 years ago
Alex Crichton	7a1b7cdf92	Implement RFC 11: Redesigning Wasmtime's APIs (#2897 ) 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.	3 years ago
Pat Hickey	0f5bdc6497	only wasi_cap_std_sync and wasi_tokio need to define WasiCtxBuilders (#2917 ) * wasmtime-wasi: re-exporting this WasiCtxBuilder was shadowing the right one wasi-common's WasiCtxBuilder is really only useful wasi_cap_std_sync and wasi_tokio to implement their own Builder on top of. This re-export of wasi-common's is 1. not useful and 2. shadow's the re-export of the right one in sync::. wasi-common: eliminate WasiCtxBuilder, make the builder methods on WasiCtx instead * delete wasi-common::WasiCtxBuilder altogether just put those methods directly on &mut WasiCtx. As a bonus, the sync and tokio WasiCtxBuilder::build functions are no longer fallible! * bench fixes * more test fixes	4 years ago
Alex Crichton	7ec073cef1	Bring back per-thread lazy initialization (#2863 ) * Bring back per-thread lazy initialization Platforms Wasmtime supports may have per-thread initialization that needs to run before WebAssembly. For example Unix needs to setup a sigaltstack and macOS needs to set up mach ports. In #2757 this per-thread setup was moved out of the invocation of a wasm function, relying on the lack of Send for Store to initialize the thread at Store creation time and never worry about it later. This conflicted with [wasmtime's desired multithreading story](https://github.com/bytecodealliance/wasmtime/pull/2812) so a new [`Store::notify_switched_thread` was added](https://github.com/bytecodealliance/wasmtime/pull/2822) to explicitly indicate a Store has moved to another thread (if it unsafely did so). It turns out though that it's not always easy to determine when a `Store` moves to a new thread. For example the Go bindings for Wasmtime are generally unaware when a goroutine switches OS threads. This led to https://github.com/bytecodealliance/wasmtime-go/issues/74 where a SIGILL was left uncaught, making it appear that traps aren't working properly. This commit revisits the decision in #2757 and moves per-thread initialization back into the path of calling into WebAssembly. This is differently from before, though, where there's still only one TLS access on the path of calling into WebAssembly, unlike before where it was a separate access. This allows us to get the speed benefits of #2757 as well as the flexibility benefits of not having to explicitly move a store between threads. With this new ability this commit deletes the recently added `Store::notify_switched_thread` method since it's no longer necessary. * Fix a test compiling	4 years ago
Benjamin Bouvier	ba73b458b8	Introduce a new API that allows notifying that a Store has moved to a new thread (#2822 ) * Introduce a new API that allows notifying that a Store has moved to a new thread * Add backlink to documentation, and mention the new API in the multithreading doc;	4 years ago
Benjamin Bouvier	7588565078	Tweaks some tests for Mac aarch64 - some tests don't pass because of bad interactions with the system's libunwind; ignore them for now. - the page size on mac aarch64 is 16K, not 4K; tweak some tests which were expecting 4K or multiples of 4K pages to use a multiple of host page size instead. - a cranelift-native test needed an update for the new calling convention.	4 years ago
Chris Fallin	cb48ea406e	Switch default to new x86_64 backend. This PR switches the default backend on x86, for both the `cranelift-codegen` crate and for Wasmtime, to the new (`MachInst`-style, `VCode`-based) backend that has been under development and testing for some time now. The old backend is still available by default in builds with the `old-x86-backend` feature, or by requesting `BackendVariant::Legacy` from the appropriate APIs. As part of that switch, it adds some more runtime-configurable plumbing to the testing infrastructure so that tests can be run using the appropriate backend. `clif-util test` is now capable of parsing a backend selector option from filetests and instantiating the correct backend. CI has been updated so that the old x86 backend continues to run its tests, just as we used to run the new x64 backend separately. At some point, we will remove the old x86 backend entirely, once we are satisfied that the new backend has not caused any unforeseen issues and we do not need to revert.	4 years ago
Pat Hickey	ae4c5a9d7f	fixes in tests and examples	4 years ago
Alex Crichton	2697a18d2f	Redo the statically typed `Func` API (#2719 ) * Redo the statically typed `Func` API This commit reimplements the `Func` API with respect to statically typed dispatch. Previously `Func` had a `getN` and `getN_async` family of methods which were implemented for 0 to 16 parameters. The return value of these functions was an `impl Fn(..)` closure with the appropriate parameters and return values. There are a number of downsides with this approach that have become apparent over time: * The addition of `_async` doubled the API surface area (which is quite large here due to one-method-per-number-of-parameters). The [documentation of `Func`][old-docs] are quite verbose and feel "polluted" with all these getters, making it harder to understand the other methods that can be used to interact with a `Func`. * These methods unconditionally pay the cost of returning an owned `impl Fn` with a `'static` lifetime. While cheap, this is still paying the cost for cloning the `Store` effectively and moving data into the closed-over environment. * Storage of the return value into a struct, for example, always requires `Box`-ing the returned closure since it otherwise cannot be named. * Recently I had the desire to implement an "unchecked" path for invoking wasm where you unsafely assert the type signature of a wasm function. Doing this with today's scheme would require doubling (again) the API surface area for both async and synchronous calls, further polluting the documentation. The main benefit of the previous scheme is that by returning a `impl Fn` it was quite easy and ergonomic to actually invoke the function. In practice, though, examples would often have something akin to `.get0::<()>()?()?` which is a lot of things to interpret all at once. Note that `get0` means "0 parameters" yet a type parameter is passed. There's also a double function invocation which looks like a lot of characters all lined up in a row. Overall, I think that the previous design is starting to show too many cracks and deserves a rewrite. This commit is that rewrite. The new design in this commit is to delete the `getN{,_async}` family of functions and instead have a new API: impl Func { fn typed<P, R>(&self) -> Result<&Typed<P, R>>; } impl Typed<P, R> { fn call(&self, params: P) -> Result<R, Trap>; async fn call_async(&self, params: P) -> Result<R, Trap>; } This should entirely replace the current scheme, albeit by slightly losing ergonomics use cases. The idea behind the API is that the existence of `Typed<P, R>` is a "proof" that the underlying function takes `P` and returns `R`. The `Func::typed` method peforms a runtime type-check to ensure that types all match up, and if successful you get a `Typed` value. Otherwise an error is returned. Once you have a `Typed` then, like `Func`, you can either `call` or `call_async`. The difference with a `Typed`, however, is that the params/results are statically known and hence these calls can be much more efficient. This is a much smaller API surface area from before and should greatly simplify the `Func` documentation. There's still a problem where `Func::wrapN_async` produces a lot of functions to document, but that's now the sole offender. It's a nice benefit that the statically-typed-async verisons are now expressed with an `async` function rather than a function-returning-a-future which makes it both more efficient and easier to understand. The type `P` and `R` are intended to either be bare types (e.g. `i32`) or tuples of any length (including 0). At this time `R` is only allowed to be `()` or a bare `i32`-style type because multi-value is not supported with a native ABI (yet). The `P`, however, can be any size of tuples of parameters. This is also where some ergonomics are lost because instead of `f(1, 2)` you now have to write `f.call((1, 2))` (note the double-parens). Similarly `f()` becomes `f.call(())`. Overall I feel that this is a better tradeoff than before. While not universally better due to the loss in ergonomics I feel that this design is much more flexible in terms of what you can do with the return value and also understanding the API surface area (just less to take in). [old-docs]: https://docs.rs/wasmtime/0.24.0/wasmtime/struct.Func.html#method.get0 * Rename Typed to TypedFunc * Implement multi-value returns through `Func::typed` * Fix examples in docs * Fix some more errors * More test fixes * Rebasing and adding `get_typed_func` * Updating tests * Fix typo * More doc tweaks * Tweak visibility on `Func::invoke` * Fix tests again	4 years ago
Peter Huene	54c07d8f16	Implement shared host functions. (#2625 ) * Implement defining host functions at the Config level. This commit introduces defining host functions at the `Config` rather than with `Func` tied to a `Store`. The intention here is to enable a host to define all of the functions once with a `Config` and then use a `Linker` (or directly with `Store::get_host_func`) to use the functions when instantiating a module. This should help improve the performance of use cases where a `Store` is short-lived and redefining the functions at every module instantiation is a noticeable performance hit. This commit adds `add_to_config` to the code generation for Wasmtime's `Wasi` type. The new method adds the WASI functions to the given config as host functions. This commit adds context functions to `Store`: `get` to get a context of a particular type and `set` to set the context on the store. For safety, `set` cannot replace an existing context value of the same type. `Wasi::set_context` was added to set the WASI context for a `Store` when using `Wasi::add_to_config`. * Add `Config::define_host_func_async`. * Make config "async" rather than store. This commit moves the concept of "async-ness" to `Config` rather than `Store`. Note: this is a breaking API change for anyone that's already adopted the new async support in Wasmtime. Now `Config::new_async` is used to create an "async" config and any `Store` associated with that config is inherently "async". This is needed for async shared host functions to have some sanity check during their execution (async host functions, like "async" `Func`, need to be called with the "async" variants). * Update async function tests to smoke async shared host functions. This commit updates the async function tests to also smoke the shared host functions, plus `Func::wrap0_async`. This also changes the "wrap async" method names on `Config` to `wrap$N_host_func_async` to slightly better match what is on `Func`. * Move the instance allocator into `Engine`. This commit moves the instantiated instance allocator from `Config` into `Engine`. This makes certain settings in `Config` no longer order-dependent, which is how `Config` should ideally be. This also removes the confusing concept of the "default" instance allocator, instead opting to construct the on-demand instance allocator when needed. This does alter the semantics of the instance allocator as now each `Engine` gets its own instance allocator rather than sharing a single one between all engines created from a configuration. * Make `Engine::new` return `Result`. This is a breaking API change for anyone using `Engine::new`. As creating the pooling instance allocator may fail (likely cause is not enough memory for the provided limits), instead of panicking when creating an `Engine`, `Engine::new` now returns a `Result`. * Remove `Config::new_async`. This commit removes `Config::new_async` in favor of treating "async support" as any other setting on `Config`. The setting is `Config::async_support`. * Remove order dependency when defining async host functions in `Config`. This commit removes the order dependency where async support must be enabled on the `Config` prior to defining async host functions. The check is now delayed to when an `Engine` is created from the config. * Update WASI example to use shared `Wasi::add_to_config`. This commit updates the WASI example to use `Wasi::add_to_config`. As only a single store and instance are used in the example, it has no semantic difference from the previous example, but the intention is to steer users towards defining WASI on the config and only using `Wasi::add_to_linker` when more explicit scoping of the WASI context is required.	4 years ago
Pat Hickey	8e015ca9e7	traps needed stdio	4 years ago
Pat Hickey	8313a62e46	fix test	4 years ago
Alex Crichton	51c1d4bbd6	Provide filename/line number information in `Trap` (#2452 ) * Provide filename/line number information in `Trap` This commit extends the `Trap` type and `Store` to retain DWARF debug information found in a wasm file unconditionally, if it's present. This then enables us to print filenames and line numbers which point back to actual source code when a trap backtrace is printed. Additionally the `FrameInfo` type has been souped up to return filename/line number information as well. The implementation here is pretty simplistic currently. The meat of all the work happens in `gimli` and `addr2line`, and otherwise wasmtime is just schlepping around bytes of dwarf debuginfo here and there! The general goal here is to assist with debugging when using wasmtime because filenames and line numbers are generally orders of magnitude better even when you already have a stack trace. Another nicety here is that backtraces will display inlined frames (learned through debug information), improving the experience in release mode as well. An example of this is that with this file: ```rust fn main() { panic!("hello"); } ``` we get this stack trace: ``` $ rustc foo.rs --target wasm32-wasi -g $ cargo run foo.wasm Finished dev [unoptimized + debuginfo] target(s) in 0.16s Running `target/debug/wasmtime foo.wasm` thread 'main' panicked at 'hello', foo.rs:2:5 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace Error: failed to run main module `foo.wasm` Caused by: 0: failed to invoke command default 1: wasm trap: unreachable wasm backtrace: 0: 0x6c1c - panic_abort::__rust_start_panic::abort::h2d60298621b1ccbf at /rustc/7eac88abb2e57e752f3302f02be5f3ce3d7adfb4/library/panic_abort/src/lib.rs:77:17 - __rust_start_panic at /rustc/7eac88abb2e57e752f3302f02be5f3ce3d7adfb4/library/panic_abort/src/lib.rs:32:5 1: 0x68c7 - rust_panic at /rustc/7eac88abb2e57e752f3302f02be5f3ce3d7adfb4/library/std/src/panicking.rs:626:9 2: 0x65a1 - std::panicking::rust_panic_with_hook::h2345fb0909b53e12 at /rustc/7eac88abb2e57e752f3302f02be5f3ce3d7adfb4/library/std/src/panicking.rs:596:5 3: 0x1436 - std::panicking::begin_panic::{{closure}}::h106f151a6db8c8fb at /rustc/7eac88abb2e57e752f3302f02be5f3ce3d7adfb4/library/std/src/panicking.rs:506:9 4: 0xda8 - std::sys_common::backtrace::__rust_end_short_backtrace::he55aa13f22782798 at /rustc/7eac88abb2e57e752f3302f02be5f3ce3d7adfb4/library/std/src/sys_common/backtrace.rs:153:18 5: 0x1324 - std::panicking::begin_panic::h1727e7d1d719c76f at /rustc/7eac88abb2e57e752f3302f02be5f3ce3d7adfb4/library/std/src/panicking.rs:505:12 6: 0xfde - foo::main::h2db1313a64510850 at /Users/acrichton/code/wasmtime/foo.rs:2:5 7: 0x11d5 - core::ops::function::FnOnce::call_once::h20ee1cc04aeff1fc at /rustc/7eac88abb2e57e752f3302f02be5f3ce3d7adfb4/library/core/src/ops/function.rs:227:5 8: 0xddf - std::sys_common::backtrace::__rust_begin_short_backtrace::h054493e41e27e69c at /rustc/7eac88abb2e57e752f3302f02be5f3ce3d7adfb4/library/std/src/sys_common/backtrace.rs:137:18 9: 0x1d5a - std::rt::lang_start::{{closure}}::hd83784448d3fcb42 at /rustc/7eac88abb2e57e752f3302f02be5f3ce3d7adfb4/library/std/src/rt.rs:66:18 10: 0x69d8 - core::ops::function::impls::<impl core::ops::function::FnOnce<A> for &F>::call_once::h564d3dad35014917 at /rustc/7eac88abb2e57e752f3302f02be5f3ce3d7adfb4/library/core/src/ops/function.rs:259:13 - std::panicking::try::do_call::hdca4832ace5a8603 at /rustc/7eac88abb2e57e752f3302f02be5f3ce3d7adfb4/library/std/src/panicking.rs:381:40 - std::panicking::try::ha8624a1a6854b456 at /rustc/7eac88abb2e57e752f3302f02be5f3ce3d7adfb4/library/std/src/panicking.rs:345:19 - std::panic::catch_unwind::h71421f57cf2bc688 at /rustc/7eac88abb2e57e752f3302f02be5f3ce3d7adfb4/library/std/src/panic.rs:382:14 - std::rt::lang_start_internal::h260050c92cd470af at /rustc/7eac88abb2e57e752f3302f02be5f3ce3d7adfb4/library/std/src/rt.rs:51:25 11: 0x1d0c - std::rt::lang_start::h0b4bcf3c5e498224 at /rustc/7eac88abb2e57e752f3302f02be5f3ce3d7adfb4/library/std/src/rt.rs:65:5 12: 0xffc - <unknown>!__original_main 13: 0x393 - __muloti4 at /cargo/registry/src/github.com-1ecc6299db9ec823/compiler_builtins-0.1.35/src/macros.rs:269 ``` This is relatively noisy by default but there's filenames and line numbers! Additionally frame 10 can be seen to have lots of frames inlined into it. All information is always available to the embedder but we could try to handle the `__rust_begin_short_backtrace` and `__rust_end_short_backtrace` markers to trim the backtrace by default as well. The only gotcha here is that it looks like `__muloti4` is out of place. That's because the libc that Rust ships with doesn't have dwarf information, although I'm not sure why we land in that function for symbolizing it... * Add a configuration switch for debuginfo * Control debuginfo by default with `WASM_BACKTRACE_DETAILS` * Try cpp_demangle on demangling as well * Rename to WASMTIME_BACKTRACE_DETAILS	4 years ago
Yury Delendik	b2b7bc10e2	machinst aarch64: New backend unwind (#2313 ) * Unwind information for aarch64 backend.	4 years ago
Alex Crichton	a277cf5ee4	Store `WasmFuncType` in `FuncType` (#2365 ) This commit updates `wasmtime::FuncType` to exactly store an internal `WasmFuncType` from the cranelift crates. This allows us to remove a translation layer when we are given a `FuncType` and want to get an internal cranelift type out as a result. The other major change from this commit was changing the constructor and accessors of `FuncType` to be iterator-based instead of exposing implementation details.	4 years ago
Leonardo Yvens	bde9555793	Add Trap::trap_code (#2309 ) * add Trap::trap_code * Add non-exhaustive wasmtime::TrapCode * wasmtime: Better document TrapCode * move and refactor test	4 years ago
Yury Delendik	de4af90af6	machinst x64: New backend unwind (#2266 ) Addresses unwind for experimental x64 backend. The preliminary code enables backtrace on SystemV call convension.	4 years ago
Benjamin Bouvier	79abcdb035	machinst x64: add testing to the CI;	4 years ago
Yury Delendik	15c68f2cc1	Disconnects `Store` state fields from `Compiler` (#1761 ) * Moves CodeMemory, VMInterrupts and SignatureRegistry from Compiler * CompiledModule holds CodeMemory and GdbJitImageRegistration * Store keeps track of its JIT code * Makes "jit_int.rs" stuff Send+Sync * Adds the threads example.	4 years ago
Nick Fitzgerald	a8ee0554a9	wasmtime: Initial, partial support for `externref` This is enough to get an `externref -> externref` identity function passing. However, `externref`s that are dropped by compiled Wasm code are (safely) leaked. Follow up work will leverage cranelift's stack maps to resolve this issue.	5 years ago
Leonardo Yvens	0b3b9c298e	impl From<anyhow::Error> for Trap (#1753 ) * From<anyhow::Error> for Trap * Add TrapReason::Error * wasmtime: Improve Error to Trap conversion * Remove Trap::message	5 years ago
Alex Crichton	db92dcd990	Update test ignore annotations for aarch64 (#1643 ) Looks like everything is in general passing now so it's probably time to close #1521 and all other remaining tests that are failing are classified under new more focused issues. Closes #1521	5 years ago
Alex Crichton	d1aa86f91a	Add AArch64 tests to CI (#1526 ) * Add AArch64 tests to CI This commit enhances our CI with an AArch64 builder. Currently we have no physical hardware to run on so for now we run all tests in an emulator. The AArch64 build is cross-compiled from x86_64 from Linux. Tests all happen in release mode with a recent version of QEMU (recent version because it's so much faster, and in release mode because debug mode tests take quite a long time in an emulator). The goal here was not to get all tests passing on CI, but rather to get AArch64 running on CI and get it green at the same time. To achieve that goal many tests are now ignored on aarch64 platforms. Many tests fail due to unimplemented functionality in the aarch64 backend (#1521), and all wasmtime tests involving compilation are also disabled due to panicking attempting to generate generate instruction offset information for trap symbolication (#1523). Despite this, though, all Cranelift tests and other wasmtime tests should be runnin on AArch64 through QEMU with this PR. Additionally we'll have an AArch64 binary release of Wasmtime for Linux, although it won't be too useful just yet since it will panic on almost all wasm modules. * Review comments	5 years ago
Dan Gohman	9364eb1d98	Refactor (#1524 ) * Compute instance exports on demand. Instead having instances eagerly compute a Vec of Externs, and bumping the refcount for each Extern, compute Externs on demand. This also enables `Instance::get_export` to avoid doing a linear search. This also means that the closure returned by `get0` and friends now holds an `InstanceHandle` to dynamically hold the instance live rather than being scoped to a lifetime. * Compute module imports and exports on demand too. And compute Extern::ty on demand too. * Add a utility function for computing an ExternType. * Add a utility function for looking up a function's signature. * Add a utility function for computing the ValType of a Global. * Rename wasmtime_environ::Export to EntityIndex. This helps differentiate it from other Export types in the tree, and describes what it is. * Fix a typo in a comment. * Simplify module imports and exports. * Make `Instance::exports` return the export names. This significantly simplifies the public API, as it's relatively common to need the names, and this avoids the need to do a zip with `Module::exports`. This also changes `ImportType` and `ExportType` to have public members instead of private members and accessors, as I find that simplifies the usage particularly in cases where there are temporary instances. * Remove `Instance::module`. This doesn't quite remove `Instance`'s `module` member, it gets a step closer. * Use a InstanceHandle utility function. * Don't consume self in the `Func::get` methods. Instead, just create a closure containing the instance handle and the export for them to call. Use `ExactSizeIterator` to avoid needing separate `num_` methods. Rename `Extern::func()` etc. to `into_func()` etc. * Revise examples to avoid using `nth`. * Add convenience methods to instance for getting specific extern types. * Use the convenience functions in more tests and examples. * Avoid cloning strings for `ImportType` and `ExportType`. * Remove more obviated clone() calls. * Simplify `Func`'s closure state. * Make wasmtime::Export's fields private. This makes them more consistent with ExportType. * Fix compilation error. * Make a lifetime parameter explicit, and use better lifetime names. Instead of 'me, use 'instance and 'module to make it clear what the lifetime is. * More lifetime cleanups.	5 years ago
Alex Crichton	4c82da440a	Move most wasmtime tests into one test suite (#1544 ) * Move most wasmtime tests into one test suite This commit moves most wasmtime tests into a single test suite which gets compiled into one executable instead of having lots of test executables. The goal here is to reduce disk space on CI, and this should be achieved by having fewer executables which means fewer copies of `libwasmtime.rlib` linked across binaries on the system. More importantly though this means that DWARF debug information should only be in one executable rather than duplicated across many. * Share more build caches Globally set `RUSTFLAGS` to `-Dwarnings` instead of individually so all build steps share the same value. * Allow some dead code in cranelift-codegen Prevents having to fix all warnings for all possible feature combinations, only the main ones which come up. * Update some debug file paths	5 years ago
Alex Crichton	99adc1d218	Keep frame info registered until internal instance is gone (#1514 ) This commit fixes an issue where the global registration of frame data goes away once the `wasmtime::Module` has been dropped. Even after this has been dropped, though, there may still be `wasmtime::Func` instances which reference the original module, so it's only once the underlying `wasmtime_runtime::Instance` has gone away that we can drop everything. Closes #1479	5 years ago
Alex Crichton	be85242a3f	Expose precise offset information in `wasmtime::FrameInfo` (#1495 ) * Consolidate trap/frame information This commit removes `TrapRegistry` in favor of consolidating this information in the `FRAME_INFO` we already have in the `wasmtime` crate. This allows us to keep information generally in one place and have one canonical location for "map this PC to some original wasm stuff". The intent for this is to next update with enough information to go from a program counter to a position in the original wasm file. * Expose module offset information in `FrameInfo` This commit implements functionality for `FrameInfo`, the wasm stack trace of a `Trap`, to return the module/function offset. This allows knowing the precise wasm location of each stack frame, instead of only the main trap itself. The intention here is to provide more visibility into the wasm source when something traps, so you know precisely where calls were and where traps were, in order to assist in debugging. Eventually we might use this information for mapping back to native source languages as well (given sufficient debug information). This change makes a previously-optional artifact of compilation always computed on the cranelift side of things. This `ModuleAddressMap` is then propagated to the same store of information other frame information is stored within. This also removes the need for passing a `SourceLoc` with wasm traps or to wasm trap creation, since the backtrace's wasm frames will be able to infer their own `SourceLoc` from the relevant program counters.	5 years ago
Alex Crichton	bd374fd6fc	Add Wasmtime-specific C API functions to return errors (#1467 ) * Add Wasmtime-specific C API functions to return errors This commit adds new `wasmtime_` symbols to the C API, many of which mirror the existing counterparts in the `wasm.h` header. These APIs are enhanced in a number of respects: Detailed error information is now available through a `wasmtime_error_t`. Currently this only exposes one function which is to extract a string version of the error. * There is a distinction now between traps and errors during instantiation and function calling. Traps only happen if wasm traps, and errors can happen for things like runtime type errors when interacting with the API. * APIs have improved safety with respect to embedders where the lengths of arrays are now taken as explicit parameters rather than assumed from other parameters. * Handle trap updates * Update C examples * Fix memory.c compile on MSVC * Update test assertions * Refactor C slightly * Bare-bones .NET update * Remove bogus nul handling	5 years ago

47 Commits (cf28c228d280d5e30817002cb886a78104325ba3)