Changes in stacks.rs

b19f6cc3 - Fix a `stacks` fuzzer regression (#12755)

Fri, 20 Mar 2026 13:22:15 +0000

Fix a `stacks` fuzzer regression (#12755)This commit fixes an accidental mistake from #12542 where when the`limit` of stack frames for the fuzzer to capture is `None` then itmeant that backtraces were never captured. This updates the assertionlogic to handle a missing `WasmBacktrace` and the case that`stacks.limit` is `None`. List of files: /wasmtime-44.0.1/crates/fuzzing/src/oracles/stacks.rs

c8764ed0 - Limit the number of frames in backtrace collection (#12542)

Wed, 18 Feb 2026 15:49:55 +0000

Limit the number of frames in backtrace collection (#12542)* Limit the number of frames in backtrace collectionAdd `Config::wasm_backtrace_max_frames` option to limit the number offrames collected in backtraces and set the default at 20. This helpsprevent expensive work from very deep call stacks.Setting the value to 0 is the same as disabling backtraces and so thischange deprecates `Config::wasm_backtrace`.Addresses https://github.com/bytecodealliance/wasmtime/issues/5052* review comments* fix tests* formatting* fix stack overflow test* fix docs and fuzzing* configure backtraces when fuzzing List of files: /wasmtime-44.0.1/crates/fuzzing/src/oracles/stacks.rs

93d22fcd - Migrate fuzzing to `wasmtime::error` (#12263)

Wed, 07 Jan 2026 21:51:23 +0000

Migrate fuzzing to `wasmtime::error` (#12263)* Migrate fuzzing to `wasmtime::error`* fix List of files: /wasmtime-44.0.1/crates/fuzzing/src/oracles/stacks.rs

882f22a7 - Cleanup/add some testing in `wasmtime-fuzzing` (#12038)

Tue, 18 Nov 2025 17:04:40 +0000

Cleanup/add some testing in `wasmtime-fuzzing` (#12038)Share the fuzz-generator-helpers across more tests and add smoke testsfor the dynamic/static component API tests too. List of files: /wasmtime-44.0.1/crates/fuzzing/src/oracles/stacks.rs

2bac6574 - Update the `log` dependency (#11197)

Mon, 07 Jul 2025 23:25:45 +0000

Update the `log` dependency (#11197)* Update the `log` dependencyThis enables getting warnings about formatting strings in the `log`crate directives which are then additionally fixed here as well.* Update dependency directive in `Cargo.toml` List of files: /wasmtime-44.0.1/crates/fuzzing/src/oracles/stacks.rs

de469e27 - Change stack walking to stop at a precise fp (#9420)

Wed, 09 Oct 2024 18:53:06 +0000

Change stack walking to stop at a precise fp (#9420)* Change stack walking to stop at a precise fpPrior to this commit entry trampolines into wasm would record theirstack pointer at the time of the function call to wasm and then thisstack pointer was used to halt the stack walking process. The problemwith this though is that due to the `tail` ABI it's possible that thecallee will update the caller's stack pointer temporarily. This meansthat the recorded stack pointer at the time the trampoline called wasmmay differ from the callee's idea of what the stack pointer is when abacktrace happens.To handle this condition when stack walking the frame pointer instead ofthe stack pointer is now recorded when wasm is invoked. This framepointer is a trusted value as it's managed by Cranelift itself. Thisadditionally enables the stop condition for frame walking to be aprecise "it must be this value" condition.Put together this commit fixes an issue where when `return_call` is usedit's possible for the initial few frames of the stack to get lost instack traces. After this the frame pointer chain should always beprecisely walked in its entirety, even in the face of different numbersof arguments and parameters as `return_call` instructions are executed.* Add tail-calls, params, and results to stacks fuzzerThis commit extends the preexisting `stacks` fuzzer with a few newfeatures:* `return_call` instructions are now generated* functions may have both params/results to exercise logic around stack adjustments and how that might affect a stack trace List of files: /wasmtime-44.0.1/crates/fuzzing/src/oracles/stacks.rs

9ce3ffe1 - Update some CI dependencies (#7983)

Thu, 22 Feb 2024 23:54:03 +0000

Update some CI dependencies (#7983)* Update some CI dependencies* Update to the latest nightly toolchain* Update mdbook* Update QEMU for cross-compiled testing* Update `cargo nextest` for usage with MIRIprtest:full* Remove lots of unnecessary imports* Downgrade qemu as 8.2.1 seems to segfault* Remove more imports* Remove unused winch trait method* Fix warnings about unused trait methods* More unused imports* More unused imports List of files: /wasmtime-44.0.1/crates/fuzzing/src/oracles/stacks.rs

b0939f66 - Remove explicit `S` type parameters (#5275)

Wed, 16 Nov 2022 05:04:26 +0000

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 List of files: /wasmtime-44.0.1/crates/fuzzing/src/oracles/stacks.rs

2afaac51 - Return `anyhow::Error` from host functions instead of `Trap`, redesign `Trap` (#5149)

Wed, 02 Nov 2022 16:29:31 +0000

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` now work with `Result` instead where the error is `anyhow::Error`. This includes functions such as: * Host-defined functions in a `Linker` * `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` to `-> Result` 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 List of files: /wasmtime-44.0.1/crates/fuzzing/src/oracles/stacks.rs

05e6abf2 - Fix the `stacks` fuzzer in the face of stack overflow (#4557)

Mon, 01 Aug 2022 16:03:23 +0000

Fix the `stacks` fuzzer in the face of stack overflow (#4557)When the `stacks` fuzzer hits a stack overflow the trace generated by Wasmtime will have one more frame than the trace generated by the wasm itself. This comes about due to the wasm not actually pushing the final frame when it stack overflows. The host, however, will still see the final frame that triggered the stack overflow. In this situation the fuzzer asserts that the host has one extra frame and then discards the frame. List of files: /wasmtime-44.0.1/crates/fuzzing/src/oracles/stacks.rs

46782b18 - `wasmtime`: Implement fast Wasm stack walking (#4431)

Thu, 28 Jul 2022 22:46:14 +0000

`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.

Benchmarks

Traps and Stack Traces

Large improvements to taking stack traces on traps, ranging from shaving off 64% to 99.95% of the time it used to take.

``` 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 ```

Calls

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.

``` 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 ```

* 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 Co-authored-by: Alex Crichton List of files: /wasmtime-44.0.1/crates/fuzzing/src/oracles/stacks.rs