Changes in runtime.rs

e069bdd3 - `CodeBuilder` APIs for defining compile-time builtins (#11918)

Thu, 23 Oct 2025 18:46:59 +0000

`CodeBuilder` APIs for defining compile-time builtins (#11918)* `CodeBuilder` APIs for defining compile-time builtinsCompile-time builtins, as described in [theRFC](https://github.com/bytecodealliance/rfcs/blob/main/accepted/wasmtime-compile-time-builtins.md),are effectively the sum of three parts:1. Function inlining2. Unsafe intrinsics3. Component compositionThe first two have already been implemented in Wasmtime. This commit implementsthe final part, leveraging `wasm-compose` to link host-defined compile-timebuiltin components with guest-defined main components. It exposes Wasmtime'sunsafe intrinsics only to the host-defined compile-time builtins, not theguest-defined main Wasm component.Why `wasm-compose` and not `wac`? Because it is in the same repo as the rest ofthe `wasm-tools` crates, and therefore it is easy to depend on without bringingin duplicate copies of that family of crates into our workspace and builds. Alsoits programmatic API is somewhat easier to use, and is not spread acrossmultiple crates.* Fix unused lifetime in `cfg(not(feature = "compile-time-builtins"))`* Fix an unused warning when `cfg(not(feature = "compile-time-builtins"))`* Add cargo vet audit for `fixedbitset` version `0.4.2`* Add cargo vet audit for `bitmaps` version 2.10.0* Add cargo vet audit for `sized-chunks` diff `0.6.5 -> 0.7.0`* Add/tweak cargo vet exemptions for some depsThese all have >10,000 daily downloads, and so are okay to exempt per ourpolicy:https://docs.wasmtime.dev/contributing-coding-guidelines.html#policy-for-adding-cargo-vet-entries* Add cargo vet audit for `wasm-compose` diff `0.236.0 -> 0.238.1`Don't know why I have to do this certification even though we have a wildcardaudit for this crate because it is authored by the Bytecode Alliance...* Fix visibility of type* Move compile-time builtins methods to module to cut down on `cfg`s* Skip checking `heck` in `cargo deny`Until https://github.com/bytecodealliance/wasm-tools/pull/2359 is merged,released, and updated in this tree.* Always read compile-time inputs* Tighten up parse loop and level tracking* as_deref instead of clone* Remove 'b lifetime from CodeBuilder* fix `cfg(not(feature = "compile-time-builtins"))` build* Ignore tests that run wasm when in MIRI List of files: /wasmtime-44.0.1/crates/wasmtime/src/compile/runtime.rs

ad56ff98 - Implement unsafe intrinsics for compile-time builtins (#11825)

Fri, 17 Oct 2025 00:01:54 +0000

Implement unsafe intrinsics for compile-time builtins (#11825)* Implement unsafe intrinsics for compile-time builtinsThis commit adds the extremely unsafe`wasmtime::CodeBuilder::expose_unsafe_intrinsics` method. When enabled, the Wasmbeing compiled is given access to special imports that correspond to direct,unchecked and unsandboxed, native load and store operations. These intrinsicsare intended to be used for implementing fast, inline-able versions of WASIinterfaces that are special-cased to a particular host embedding, for example.Compile-time builtins, as originally described in [theRFC](https://github.com/bytecodealliance/rfcs/pull/43), are basically made up ofthree parts:1. A function inliner2. Unsafe intrinsics3. Component composition to encapsulate the usage of unsafe intrinsics in a safeinterfacePart (1) has been implemented in Wasmtime and Cranelift for a little whilenow (see `wasmtime::Config::compiler_inlining`). This commit is part (2). Afterthis commit lands, part (3) can be done with `wac` and `wasm-compose`, althoughfollow up work is required to make the developer experience nicer and moreintegrated into Wasmtime so that the APIs can look like those proposed in theRFC.* fill out some more docs* fix non component model builds* start filling out the doc example* Factor abi params/returns out; truncate/extend pointers* Compile unsafe intrinsics on winch as well* prtest:full* have the macro define the signature* ignore tests in MIRI because MIRI can't compile Wasm* juggle pointer provenance in `Store::data[_mut]`* add a test for store data provenance and also fix it* use `VmPtr` for the store data pointer* finish writing unsafe intrinsics example* fix up docs and rules around only accessing data from `T` in a `Store`* Only reserve space for the intrinsics' `VMFuncRef`s if they are in use* use dangling pointers instead of options* Rename `StoreInner::data` to `data_no_provenance` and fix some accesses to use the method accessors* Add comments about the provenance juggling inside `StoreInner::data[_mut]`* only compile intrinsics that are usedTurns out we don't need to add phases, we already have the info available to dothis.* fix duplicate symbol names List of files: /wasmtime-44.0.1/crates/wasmtime/src/compile/runtime.rs

703871a2 - Enable the `useless_conversion` Clippy lint (#10838)

Tue, 27 May 2025 16:49:22 +0000

Enable the `useless_conversion` Clippy lint (#10838)* Enable the `useless_conversion` Clippy lintWe've got lots of types in Wasmtime and convert between them quite alot, but often over time conversions become unnecessary throughrefactorings or similar. This will hopefully enable us to clean up someconversions as they come up to try to have as few as possible ideally.* Review comments List of files: /wasmtime-44.0.1/crates/wasmtime/src/compile/runtime.rs

2cd52b76 - Allow creation of a CacheConfig without loading from a file (#10665)

Tue, 29 Apr 2025 14:50:26 +0000

Allow creation of a CacheConfig without loading from a file (#10665)* cache: Add builder pattern for CacheConfig* wasmtime: Add cache_config method to wasmtime::Config* Refactor test_builder_default to use test_prolog helper* Remove enabled option from CacheConfigBuilder and always set to true* Change builder methods to take &mut self and return &mut Self* Simplify cache configuration APIA new `cache_config(Option)` method replaces multiple methodsfor controlling module caching. Now `None` disables caching, and users candirectly provide a cache config or load one from a file.* Make cache configuration optional* Add Cache struct to separate configuration from runtime (wip)* Ensure default values earlier* Consolidate CacheConfig and CacheConfigBuilder* Set Cache directly on wastime::Config and make it easier to create onefrom a file* Validate after loading file again* Move cache to top-level module* Fix tests List of files: /wasmtime-44.0.1/crates/wasmtime/src/compile/runtime.rs

6dae7eb8 - Enable warnings if `cache` is disabled (#10140)

Tue, 28 Jan 2025 17:59:10 +0000

Enable warnings if `cache` is disabled (#10140)Continuation of work in #10131 List of files: /wasmtime-44.0.1/crates/wasmtime/src/compile/runtime.rs

5eee6313 - Wasmtime: support a notion of "custom code publisher". (#9778)

Tue, 10 Dec 2024 23:56:25 +0000

Wasmtime: support a notion of "custom code publisher". (#9778)* Wasmtime: support a notion of "custom code publisher".In some `no_std` environments, virtual memory usage is *generally*prohibited for performance-predictability reasons, but the MMUhardware is still in use for permissions (e.g., `W^X`write-xor-execute). Occasional changes to page mapping permissions arethus necessary when new modules are loaded dynamically, and areacceptable in that context. Wasmtime needs a way to support"publishing" code (making it executable) in such environments.Rather than try to segment the `signals-based-traps` divide further,and piece out the code-publishing parts from the heap parts, andbackdoor a path to `mprotect` in an otherwise `no_std` build, in thisPR I have opted to add a trait an impl of which the embedder canprovide to the `Config` to implement custom actions for "codepublish". This otherwise operates properly in ano-`signals-based-traps` environment, e.g., the module backing memoryitself is regularly allocated rather than mmap'd (but is now alignedto the degree requested by the trait impl).* Review feedback.* Plumb through custom alignment for runtime code generation* Add a test for custom code memory. List of files: /wasmtime-44.0.1/crates/wasmtime/src/compile/runtime.rs

d3132c9d - Add a `signals-based-traps` Cargo compile-time feature (#9614)

Tue, 19 Nov 2024 19:21:36 +0000

Add a `signals-based-traps` Cargo compile-time feature (#9614)* Gate signal handlers behind a new Cargo featureThis commit adds a new on-by-default Cargo feature to the `wasmtime`crate named `signals-based-traps`. This is modeled after the`Config::signals_based_traps` configuration at runtime and can be usedto statically disable the use of signal handlers in Wasmtime. Thisnotably reduces the number of platform dependencies that Wasmtime hasand provides a mode of avoiding relying on signals altogether.This introduces a new `MallocMemory` which is a linear memory backed bythe system allocator. This new type of memory is enabled when virtualmemory guards are disabled and signals-based-traps are disabled. Thismeans that this new type of memory will be candidate for fuzzing forexample.prtest:full* Fix rebase conflict* Refactor `MmapVec` documentation and representation* Remove no-longer-needed `Arc`* Document it may be backed by `Vec` List of files: /wasmtime-44.0.1/crates/wasmtime/src/compile/runtime.rs

f673cde3 - Refactor use of `CodeBuilder` on the CLI (#9125)

Wed, 14 Aug 2024 17:31:07 +0000

Refactor use of `CodeBuilder` on the CLI (#9125)* Refactor use of `CodeBuilder` on the CLIThis commit refactors `wasmtime run` and `wasmtime compile` tounconditionally use `CodeBuilder` internally. This will in theory helpout in the future if more debug-related options are added to`CodeBuilder` for example. This refactoring required some changes to`CodeBuilder` to be able to support a query about whether the internalbytes were a component or a module. The text format is now converted tobinary immediately when supplied rather than during the compilationphase. This in turn required some API changes to make the selection ofsupporting the text format a compile-time choice of method rather than aruntime value.* Fix compile* Fix no-cranelift build of CLI List of files: /wasmtime-44.0.1/crates/wasmtime/src/compile/runtime.rs

1512a954 - Add `anyhow` stuff to our internal `wasmtime` crate prelude (#8804)

Fri, 14 Jun 2024 15:24:12 +0000

Add `anyhow` stuff to our internal `wasmtime` crate prelude (#8804)* Add `anyhow` stuff to our internal `wasmtime` crate preludeWe use it basically everywhere and it is annoying to have to import.I also did an audit of existing `use` statements and removed the now-redundantones and replaced one-off imports with usage of the prelude, so that the preludeis available by default in more places.* Fix `cargo doc` List of files: /wasmtime-44.0.1/crates/wasmtime/src/compile/runtime.rs

1d11b265 - Remove the native ABI calling convention from Wasmtime (#8629)

Fri, 17 May 2024 04:28:11 +0000

Remove the native ABI calling convention from Wasmtime (#8629)* Remove the native ABI calling convention from WasmtimeThis commit proposes removing the "native abi" calling convention usedin Wasmtime. For background this ABI dates back to the origins ofWasmtime. Originally Wasmtime only had `Func::call` and eventually Iadded `TypedFunc` with `TypedFunc::call` and `Func::wrap` for a fasterpath. At the time given the state of trampolines it was easiest to callWebAssembly code directly without any trampolines using the native ABIthat wasm used at the time. This is the original source of the nativeABI and it's persisted over time under the assumption that it's fasterthan the array ABI due to keeping arguments in registers rather thanspilling them to the stack.Over time, however, this design decision of using the native ABI has notaged well. Trampolines have changed quite a lot in the meantime and it'sno longer possible for the host to call wasm without a trampoline, forexample. Compilations nowadays maintain both native and arraytrampolines for wasm functions in addition to host functions. There's alarge split between `Func::new` and `Func::wrap`. Overall, there's quitea lot of weight that we're pulling for the design decision of using thenative ABI.Functionally this hasn't ever really been the end of the world.Trampolines aren't a known issue in terms of performance or code size.There's no known faster way to invoke WebAssembly from the host (orvice-versa). One major downside of this design, however, is that`Func::new` requires Cranelift as a backend to exist. This is due to thefact that it needs to synthesize various entries in the matrix of ABIswe have that aren't available at any other time. While this is itselfnot the worst of issues it means that the C API cannot be built withouta compiler because the C API does not have access to `Func::wrap`.Overall I'd like to reevaluate given where Wasmtime is today whether itmakes sense to keep the native ABI trampolines. Sure they're supposed tobe fast, but are they really that much faster than the array-call ABI asan alternative? This commit is intended to measure this.This commit removes the native ABI calling convention entirely. Forexample `VMFuncRef` is now one pointer smaller. All of `TypedFunc` nowuses `*mut ValRaw` for loads/stores rather than dealing with ABIbusiness. The benchmarks with this PR are:* `sync/no-hook/core - host-to-wasm - typed - nop` - 5% faster* `sync/no-hook/core - host-to-wasm - typed - nop-params-and-results` - 10% slower* `sync/no-hook/core - wasm-to-host - typed - nop` - no change* `sync/no-hook/core - wasm-to-host - typed - nop-params-and-results` - 7% fasterThese numbers are a bit surprising as I would have suspected no changein both "nop" benchmarks as well as both being slower in theparams-and-results benchmarks. Regardless it is apparent that this isnot a major change in terms of performance given Wasmtime's currentstate. In general my hunch is that there are more expensive sources ofoverhead than reads/writes from the stack when dealing with wasm values(e.g. trap handling, store management, etc).Overall this commit feels like a large simplification of what wecurrently do in `TypedFunc`:* The number of ABIs that Wasmtime deals with is reduced by one. ABIs are pretty much always tricky and having fewer moving parts should help improve the understandability of the system.* All of the `WasmTy` trait methods and `TypedFunc` infrastructure is simplified. Traits now work with simple `load`/`store` methods rather than various other flavors of conversion.* The multi-return-value handling of the native ABI is all gone now which gave rise to significant complexity within Wasmtime's Cranelift translation layer in addition to the `TypedFunc` backing traits.* This aligns components and core wasm where components always use the array ABI and now core wasm additionally will always use the array ABI when communicating with the host.I'll note that this still leaves a major ABI "complexity" with respectto native functions do not have a wasm ABI function pointer untilthey're "attached" to a `Store` with a `Module`. That's required toavoid needing Cranelift for creating host functions and that property isstill true today. This is a bit simpler to understand though now that`Func::new` and `Func::wrap` are treated uniformly rather than one beingspecial-cased.* Fix miri unsafetyprtest:full List of files: /wasmtime-44.0.1/crates/wasmtime/src/compile/runtime.rs

964f8986 - Use rustdoc's `doc_auto_cfg` feature instead of `doc_cfg` (#8532)

Fri, 03 May 2024 16:01:12 +0000

Use rustdoc's `doc_auto_cfg` feature instead of `doc_cfg` (#8532)This commit removes all our `#[cfg_attr(..., doc(cfg(...)))]`annotations throughout Wasmtime and `wasmtime-wasi`. These are allreplaced with `feature(doc_auto_cfg)` which automatically infers theattribute to show rather than requiring us to duplicate it.Spot-checking the docs this looks just-as-readable while being mucheasier to maintain over time. List of files: /wasmtime-44.0.1/crates/wasmtime/src/compile/runtime.rs

72004aad - Turn the `wasmtime-runtime` crate into the `wasmtime::runtime::vm` module (#8501)

Tue, 30 Apr 2024 18:52:45 +0000

Turn the `wasmtime-runtime` crate into the `wasmtime::runtime::vm` module (#8501)* Expose `wasmtime-runtime` as `crate::runtime::vm` internally for the `wasmtime` crate* Rewrite uses of `wasmtime_runtime` to `crate::runtime::vm`* Remove dep on `wasmtime-runtime` from `wasmtime-cli`* Move the `wasmtime-runtime` crate into the `wasmtime::runtime::vm` module* Update labeler for merged crates* Fix `publish verify`prtest:full List of files: /wasmtime-44.0.1/crates/wasmtime/src/compile/runtime.rs

fb4f4cd3 - Add initial support for DWARF Fission (#8055)

Wed, 24 Apr 2024 14:23:08 +0000

Add initial support for DWARF Fission (#8055)* add cloning for String attributes* use into_owned instead of to_vec to avoid a clone if possible.* runs, but does not substitute* show vars from c program, start cleanup* tiday* resolve conflicts* remove WASI folder* Add module_builderadd dwarf_package to state for cache* move dwarf loading to module_environ.rspass the dwarf as binary as low as module_environ.rs* pass dwarf package rather than add to debug_info* tidy option/result nested if* revert some toml and whitespace.* add features cranelift,winch to module_builder and compute_artifactsremove some `use`s* address some feedbackremove unused 'use's* address some feedbackremove unused 'use's* move wat feature condition to cover whole method.* More feedbackAnother try at wat feature move* Another try at wat feature move* change gimli exemption versionadd typed-arena exemption* add None for c-api* move `use` to #cfg* fix another config build* revert unwanted code deletion* move inner function closer to use* revert extra param to Module::new* workaround object crate bug.* add missing parameter* add missing parameter* Merge remote-tracking branch 'origin/main' into dwarf-att-string# Conflicts:# crates/wasmtime/src/engine.rs# crates/wasmtime/src/runtime/module.rs# src/common.rs* remove moduke* use common gimli version of 28.1* remove wasm feature, revert gimli version* remove use of object for wasm dwarf* remove NativeFile workaround, add feature for dwp loading* sync winch signature* revert bench api change* add dwarf for no cache feature* put back merge loss of module kind* remove param from docs* add dwarf fission lldb test* simplify and include test source* clang-format* address feedback, remove packagesadd docssimplify return type* remove Default use on ModuleTypesBuilder* Remove an `unwrap()` and use `if let` instead* Use `&[u8]` instead of `&Vec`* Remove an `unwrap()` and return `None` instead* Clean up some code in `transform_dwarf`* Clean up some code in `replace_unit_from_split_dwarf`* Clean up some code in `split_unit`* Minor refactorings and documentation in `CodeBuilder`* Restrict visibility of `dwarf_package_binary`* Revert supply-chain folder changes* Fix compile error on nightly* prtest:full* prtest:full* prtest:full* prtest:full* prtest:full* prtest:full* prtest:full* prtest:full* use lldb 15* prtest:full* prtest:full* load dwp when loading wasm bytes with path* correct source file name* remove debug---------Co-authored-by: Alex Crichton List of files: /wasmtime-44.0.1/crates/wasmtime/src/compile/runtime.rs

1a7de7cc - Add a `compile` feature to `wasmtime-environ` (#8250)

Thu, 28 Mar 2024 16:07:12 +0000

Add a `compile` feature to `wasmtime-environ` (#8250)* Add a `compile` feature to `wasmtime-environ`This commit adds a compile-time feature to remove some dependencies ofthe `wasmtime-environ` crate. This compiles out support for compilingmodules/components and makes the crate slimmer in terms of amount ofcode compiled along with its dependencies. Much of this should alreadyhave been statically removed by native linkers so this likely won't haveany compile-size impact, but it's a nice-to-have in terms oforganization.This has a fair bit of shuffling around of code, but apart fromrenamings and movement there are no major changes here.* Fix compile issue* Gate `ModuleTranslation` and its methods on `compile`* Fix doc link* Fix doc link List of files: /wasmtime-44.0.1/crates/wasmtime/src/compile/runtime.rs