Changes in config.rs

2f7dbd61 - PCC: remove proof-carrying code (for now?). (#12800)

Tue, 31 Mar 2026 04:36:33 +0000

PCC: remove proof-carrying code (for now?). (#12800)In late 2023, we built out an experimental feature calledProof-Carrying Code (PCC), where we attached "facts" to values in theCLIF IR and built verification of these facts after lowering tomachine instructions. We also added "memory types" describing layoutof memory and a "checked" flag on memory operations such that we couldverify that any checked memory operation accessed valid memory (asdefined by memory types attached to pointer values viafacts). Wasmtime's Cranelift backend then put appropriate memory typesand facts in its IR such that all accesses to memory (aspirationally)could be checked, taking the whole mid-end and lowering backend ofCranelift out of the trusted core that enforces SFI.This basically worked, at the time, for static memories; but never fordynamic memories, and then work on the feature lostprioritization (aka I had to work on other things) and I wasn't ableto complete it and put it in fuzzing/enable it as a production option.Unfortunately since then it has bit-rotted significantly -- as we addnew backend optimizations and instruction lowerings we haven't keptthe PCC framework up to date.Inspired by the discussion in #12497 I think it's time to deleteit (hopefully just "for now"?) unless/until we can build it again. Andwhen we do that, we should probably get it to the point of validatingrobust operation on all combinations of memory configurations beforemerging. (That implies a big experiment branch rather than a bunch ofeager PRs in-tree, but so it goes.) I still believe it is possible tobuild this (and I have ideas on how to do it!) but not right now. List of files: /wasmtime-44.0.1/crates/fuzzing/src/generators/config.rs

e50d897b - Add `bulk_memory` to wast configuration (#12883)

Mon, 30 Mar 2026 12:44:15 +0000

Add `bulk_memory` to wast configuration (#12883)Allows enabling/disabling this wasm proposal on a per-test basis. List of files: /wasmtime-44.0.1/crates/fuzzing/src/generators/config.rs

1b59b579 - Add support for map type (#12216)

Mon, 09 Mar 2026 23:34:21 +0000

Add support for map type (#12216)* Add support for map typeSigned-off-by: Yordis Prieto * Add Map and MapEntry classes to support key/value pairs in component modelThis commit introduces the Map and MapEntry classes, enabling the representation of map values in the component model. The Map class allows for the creation and iteration of key/value pairs, enhancing the functionality of the wasmtime component API. Additionally, the .gitignore file is updated to exclude build artifacts from the crates/c-api directory.* Add wasm_component_model_map configuration support* Format code* Format C code* Enhance component model to support HashMap typeThis commit introduces support for HashMap in the component model, allowing maps to be represented as list> in the canonical ABI. It includes implementations for the ComponentType, Lower, and Lift traits for HashMap, enabling type checking, lowering to flat representations, and lifting from memory. Additionally, the maximum depth for type generation in the fuzzing utility is updated to accommodate the new map type.* Refactor component configuration to introduce map supportThis commit removes the previous wasm features configuration and adds new functions for creating a map-configured engine. The `map_config` and `map_engine` functions are introduced to facilitate the use of the component model with maps in tests, ensuring that the engine is properly configured for map types in the component model.* Add new WAST test for map types and remove map type definitions from existing testsThis commit introduces a new WAST test file specifically for testing various map types in the component model. Additionally, it removes the redundant map type definitions from the existing types.wast file to streamline the test suite.* Update component fuzzing and dynamic tests to replace call_and_post_return with call* Format code* Refactor HashMap usage in typed.rs to use wasmtime_environ collections* Fix HashMap initialization and insertion to handle potential errors in typed.rs* Refactor HashMap handling in typed.rs to use lower_map_iter for improved iteration and memory management. Introduce new implementations for ComponentType, Lower, and Lift traits for std::collections::HashMap, enhancing support for map types in the component model.* Fix map adapter trampoline compilation and alignment bugsThe translate_map function had two categories of bugs preventing mapadapter trampolines from working:1. Wasm stack discipline: local_set_new_tmp emits LocalSet which pops from the stack, but was called when the stack was empty (to "pre-allocate" locals). Fixed by computing values first, then calling local_set_new_tmp to consume them—matching translate_list's pattern. Also removed an erroneous LocalTee that left an orphan value on the stack. Affected: src_byte_len, dst_byte_len, cur_src_ptr, cur_dst_ptr.2. Pointer advancement: after value translation, the pointer still points at the value start. The code only advanced by trailing padding instead of value_size + trailing_padding, causing every loop iteration to re-read the same memory.Also fixes entry layout to use proper record alignment rules (entryalign = max(key_align, value_align), value at aligned offset).* Refactor map entry layout calculations to use canonical ABI* Remove unnecessary clone of map pairs during loweringVal::Map already holds Vec<(Val, Val)> which derefs to &[(Val, Val)],matching lower_map's signature directly. The intermediate Vec allocationand deep clone of every key/value pair was redundant.* Deduplicate map lift logic between HashMap implementations* Deduplicate list and map sequence translation scaffolding* Fix cargo fmt formatting issues* Deduplicate map typecheck logic* Deduplicate map lowering with linear_lower_map_to_flat and linear_lower_map_to_memory helpers* Clean up lift_try_map: use drop, move TryHashMap import to module scope* Fix CI: arbtest overflow and no-std HashMap lift_map- component_fuzz: use saturating_sub in generate_hashable_key to prevent underflow when fuel is 0 and Enum variant is chosen- typed: remove incorrect ? operators in lift_map for hashbrown::HashMap (with_capacity and insert don't return Result)* Store map tuple layout in TypeMapCompute map entry ABI and value offsets once during type building, and reuse that metadata in runtime map lift/lower paths instead of recalculating tuple layout at each call site.* Refactor map ABI argument passingBundle map lift/lower layout and type metadata into a small MapAbi32 helper so map helper calls stay concise without changing behavior.* Fix CI: enable component_model_map in fuzzing and handle map in arbitrary_valThe fuzzer's component_api oracle was generating map types but the enginedidn't have the map feature enabled, and arbitrary_val had no arm forType::Map. Enable component_model_map in the store helper (matching howcomponent_model_async is forced on) and implement arbitrary value generationfor map types.---------Signed-off-by: Yordis Prieto List of files: /wasmtime-44.0.1/crates/fuzzing/src/generators/config.rs

332b4ce6 - fuzz: Enable winch-aarch64 (#12646)

Tue, 24 Feb 2026 16:55:02 +0000

fuzz: Enable winch-aarch64 (#12646)As of https://github.com/bytecodealliance/wasmtime/pull/11051, Winchsupports all of Core Wasm on aarch64. This commit enables fuzzingrespectively. List of files: /wasmtime-44.0.1/crates/fuzzing/src/generators/config.rs

caf0f752 - Minimal implementation of fixed-length lists to enable wit-bindgen runtime tests (#10619)

Wed, 14 Jan 2026 16:12:38 +0000

Minimal implementation of fixed-length lists to enable wit-bindgen runtime tests (#10619)* necessary parts to make the wit-bindgen test pass* post-merge fixes* fix clippy* inline type computations* link missing functionality to an issue* undo unintended removal of blank line* fix logic mistake, enable feature in wasmtime* optimized conversion* add offset* unify on name and implement wast option* cargo fmt and beautify fixed_size_list_type* add multi memory as it is needed by the test runner* standardize on the official name (component model standard) "fixed-length lists"changing wasm-tools (parser etc. is a different task)* More instances of fixed size corrected to fixed length List of files: /wasmtime-44.0.1/crates/fuzzing/src/generators/config.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/generators/config.rs

0a55f804 - "Downgrade" threads support to tier 2, disable fuzzing (#12036)

Mon, 24 Nov 2025 17:09:20 +0000

"Downgrade" threads support to tier 2, disable fuzzing (#12036)* "Downgrade" threads support to tier 2, disable fuzzingThis commit is borne out of a fuzz bug that was opened recently. Thefuzz bug specifically has to do with fallout from #12022, specifically`SharedMemory` being used to allocated instead of `Memory`. In thissituation the resource limiter is no longer consulted meaning thatshared memories bypass this and aren't caught by OOM checks. This iscurrently by design because `SharedMemory` instances don't know whichresource limiter to hook into per-store.More generally though the implementation of wasm threads, while workablein Wasmtime, has a number of known relatively large deficiencies. Thesewere not resolved prior to ungating the wasm proposal (that's on me) butnevertheless the quality of implementation is not quite up to "tier 1par" with the rest of what Wasmtime offers. Given this the threadsproposal is now downgraded to tier 2. To help minimize the impact ofthis the wasm proposal is left enabled-by-default, but creation of a`SharedMemory` in the Rust API requires opting-in via a new`Config::shared_memory` method.This commit shuffles around some documentation of wasm proposals tosplit it into tier 1/2/3 instead of on/off-by-default and then adds acolumn for whether the proposal is on-by-default.* clangformat* Fix tests* Add tests for failed creationFix an issue where defined shared memories weren't gated* Sync disabled threads stub* Fix another testprtest:full* Fix fuzzing tests* Fix dwarf tests List of files: /wasmtime-44.0.1/crates/fuzzing/src/generators/config.rs

6b1c0dfc - Disable mach ports during fuzzing (#11990)

Thu, 06 Nov 2025 21:28:27 +0000

Disable mach ports during fuzzing (#11990)Reported [here] and confirmed locally for myself it appears thatsometimes exceptions bypass our mach port thread and go to signalhandlers instead. I've got no idea why myself and it seemsnon-deterministic. Instead of trying to bottom this out I've gone aheadand just disabled mach ports during fuzzing. Mach ports are mainly thereto play nice with Breakpad and such which isn't a concern duringfuzzing, so using signals should work just as well.[here]: https://github.com/bytecodealliance/wasmtime/issues/11850#issuecomment-3493237271 List of files: /wasmtime-44.0.1/crates/fuzzing/src/generators/config.rs

e06fbf70 - Cooperative Multithreading (#11751)

Mon, 27 Oct 2025 21:39:35 +0000

Cooperative Multithreading (#11751)* Initial work* Almost compiling* Partially working* Cleanup* Fix merge* Cancellation and suspension refactoring* Remove printlns* Test with several threads* More testing* Cancellation* Fix cancellation for explicit suspends* Finish cancellation test* Store threads in the instance table* Deletion almost there* Tests all pass* Tighten up task deletion* Set thread state correctly* Store pairs of thread and task ids* Remove lift abi members* Cleanup unnecessary change* More cleanup* Cleanup* Revert cargo changes* Revert cargo changes* Comments* Comments on test* Update comments* Update comments* Add space that was removed in an earlier commit* Cleanup* Delete threads from the instance table* Revert cargo file* Remove dead code* Clippy changes* Clippy* Revert unnecessary changes* Revert unnecessary changes* Revert unnecessary changes* Revert unnecessary changes* Revert unnecessary changes* Review comments* Review feedback* Make thread IDs per-component-instance* Fix config* Tighten up completion* Clippy* Trigger full PR test* Move funcref table reading* Remove unused import* Formatting* Rename RemoveOnDrop* Review feedback* Review feedback* Move start thread closure* Review feedback* Review feedback* Correct feature for import* Review feedback* Disable failing tests* Enable fixed tests* Review feedback* Readd tests* Ignore task deletion test with Miri List of files: /wasmtime-44.0.1/crates/fuzzing/src/generators/config.rs

c2cfaa7a - Update upstream wasm spec test suite submodule (#11926)

Thu, 23 Oct 2025 20:23:07 +0000

Update upstream wasm spec test suite submodule (#11926)* Update upstream wasm spec test suite submoduleJuggle some configuration options here and there to accommodate all ofthe new tests.* Fix wasmtime-fuzzing compile* Fix miri script for table.wast* Fix a miri provenance issue List of files: /wasmtime-44.0.1/crates/fuzzing/src/generators/config.rs

152ee387 - Disable single-pass regalloc in fuzzing and add docs (#11864)

Wed, 15 Oct 2025 21:42:25 +0000

Disable single-pass regalloc in fuzzing and add docs (#11864)This commit disables the single-pass algorithm when fuzzing dueto #11850 which has discovered a few issues with it. Additionallydocumentation has been added to the configuration option indicating thatit's not recommended for security-sensitive applications to clarify itsimplementation status. List of files: /wasmtime-44.0.1/crates/fuzzing/src/generators/config.rs

c07703be - docs: fix typo (#11509)

Wed, 24 Sep 2025 12:05:09 +0000

docs: fix typo (#11509)* Update store.rs* Update types.rs* Update config.rs List of files: /wasmtime-44.0.1/crates/fuzzing/src/generators/config.rs

45f8b2a7 - Re-enable single-pass regalloc in fuzzing (#11721)

Fri, 19 Sep 2025 18:03:32 +0000

Re-enable single-pass regalloc in fuzzing (#11721)Follow-up to #11712 List of files: /wasmtime-44.0.1/crates/fuzzing/src/generators/config.rs

6a66b9a0 - Put each component in its own store in wast testing (#11686)

Thu, 11 Sep 2025 20:51:13 +0000

Put each component in its own store in wast testing (#11686)This commit refactors the `wasmtime-wast` crate to place each componentin its own store. This is in contrast to core wasm testing where allinstances get placed in the same store. The reason for this is thatcomponents, in particular async state, is only fully defined so long asa trap doesn't happen and once a trap happens it's expected the entirestore is torn down. This removes the need for the store to keep track ofexactly which instance all async tasks are associated with to ensurethat once any of them trap only the precise set of tasks necessary aretorn down. Instead Wasmtime can rely on embedders throwing away`Store` entirely.The refactoring here provides a hook in `WastContext` to configure thestore but otherwise a new store is manufactured for all componentinstances. Core wasm is unaffected. Tests are also unaffected assame-store behavior isn't actually required by any tests. List of files: /wasmtime-44.0.1/crates/fuzzing/src/generators/config.rs

be5661c0 - Disable `SinglePass` regalloc when fuzzing (#11546)

Tue, 26 Aug 2025 19:56:00 +0000

Disable `SinglePass` regalloc when fuzzing (#11546)OSS-Fuzz found #11544 and #11545 overnight so disable fuzzing for nowuntil those are fixed to avoid hindering too much progress while fuzzing. List of files: /wasmtime-44.0.1/crates/fuzzing/src/generators/config.rs

73de2ee9 - Pull in new regalloc2 with fastalloc fixes for exceptions, and re-enable and add to testing. (#11533)

Mon, 25 Aug 2025 19:22:21 +0000

Pull in new regalloc2 with fastalloc fixes for exceptions, and re-enable and add to testing. (#11533)* Revert "Cranelift/Wasmtime: disable fastalloc (single-pass) allocator for now. (#10554)"This reverts commit d52e23b09191185996792b8ef18e5fca2865ca43.* Upgrade to regalloc2 0.13.1.Pulls in bytecodealliance/regalloc2#233 to update fastalloc to supportthe looser constraints needed by exception-related changes.* cargo-vet update. List of files: /wasmtime-44.0.1/crates/fuzzing/src/generators/config.rs

3aa39239 - Exceptions: add basic support for fuzzing. (#11511)

Fri, 22 Aug 2025 17:24:40 +0000

Exceptions: add basic support for fuzzing. (#11511)* Enable use of exceptions in our fuzz module generator.This patch was provided by Alex in #11505; it is thusCo-authored-by: Alex Crichton * Add ExnRef comparison to differential result checking.---------Co-authored-by: Alex Crichton List of files: /wasmtime-44.0.1/crates/fuzzing/src/generators/config.rs

2d25f862 - WebAssembly exception-handling support. (#11326)

Thu, 21 Aug 2025 02:55:44 +0000

WebAssembly exception-handling support. (#11326)* WebAssembly exception-handling support.This PR introduces support for the [Wasm exception-handling proposal],which introduces a conventional try/catch mechanism to WebAssembly. ThePR supports modules that use `try_table` to register handlers for alexical scope; and provides `throw` and `throw_ref` that allocate (inthe first case) and throw exception objects.This PR builds on top of the work in #10510 for Cranelift-levelexception support, #10919 for an unwinder, and #11230 for exceptionobjects built on top of GC, in addition a bunch of smaller fix andenabling PRs around those.[Wasm exception-handling proposal]: https://github.com/WebAssembly/exception-handling/prtest:full* Permit UnwindToWasm to have unused fields in Pulley builds (for now).* Resolve miri-caught reborrowing issue.* Ignore exceptions tests in miri for now (Pulley not supported).* Use wasmtime_test on exceptions tests.* Get tests passing on pulley platforms* Add a check to `supports_host` for the generated test and assert failure also when that is false.* Remove `pulley_unsupported` test as it falls out of `#[wasmtime_test]`* Remove `exceptions_store` helper as it falls out of `#[wasmtime_test]`* Remove miri annotations as they fall out of `#[wasmtime_test]`* Remove dead import* Skip some unsupported tests entirely in `#[wasmtime_test]`If the selected compiler doesn't support the host at all then there's noneed to run it. Actually running it could misinterpret `CraneliftNative`as "run with pulley" otherwise, so avoid such false negatives.* Cranelift: dynamic contexts: account for outgoing-args area.---------Co-authored-by: Alex Crichton List of files: /wasmtime-44.0.1/crates/fuzzing/src/generators/config.rs

698028ce - Add a configuration knob for `PAGEMAP_SCAN` (#11433)

Thu, 14 Aug 2025 22:07:53 +0000

Add a configuration knob for `PAGEMAP_SCAN` (#11433)* Add a configuration knob for `PAGEMAP_SCAN`This commit adds `PoolingAlloationConfig::pagemap_scan` and additionallyadds `-Opooling-pagemap-scan` to configure on the CLI. This is the sametri-state configuration option as `MpkEnable` so that enum was renamedto just `Enabled` and repurposed for both options.This then additionally turns the option off-by-default instead of theprevious on-by-default-if-able-to to enable more slowly rolling out thisfeature.* Fix broken test List of files: /wasmtime-44.0.1/crates/fuzzing/src/generators/config.rs

3ecb338e - Wasmtime: Add (optional) bottom-up function inlining to Wasm compilation (#11283)

Tue, 29 Jul 2025 14:32:54 +0000

Wasmtime: Add (optional) bottom-up function inlining to Wasm compilation (#11283)* Wasmtime: Add (optional) bottom-up function inlining to Wasm compilationThis commit plumbs together two pieces of recently-added infrastructure:1. function inlining in Cranelift, and2. the parallel bottom-up inlining scheduler in Wasmtime.Sprinkle some very simple inlining heuristics on top, and this gives us functioninlining in Wasm compilation.The default Wasmtime configuration does not enable inlining, and when we doenable it, we only enable it for cross-component calls by default (sincepresumably the toolchain that produced a particular core Wasm module, like LLVM,already performed any inlining that was beneficial within that module, but thattoolchain couldn't know how that Wasm module would be getting linked togetherwith other modules via component composition, and so it could not have done anycross-component inlining). For what it is worth, there is a config knob toenable intra-module function inlining, but this is primarily for use by ourfuzzers, so that they can easily excercise and explore this new inliningfunctionality.All this plumbing required some changes to the `wasmtime_environ::Compiler`trait, since Winch cannot do inlining but Cranelift can. This is mostlyencapsulated in the new `wasmtime_environ::InliningCompiler` trait, for the mostpart. Additionally, we take care not to construct the call graph, or any otherdata structures required only by the inliner and not regular compilation, bothwhen using Winch and when using Cranelift with inlining disabled.Finally, we add a `disas` test to verify that we successfully inline a series ofcalls from a function in one component, to a cross-component adapter function,to a function in another component. Most test coverage is expected to come fromour fuzzing, however.* Fix dead code warning when not `cfg(feature = "component-model")`* fix winch trampoline compilation* Move CLI options to codegen* Move parameters into struct* Use an index set for call-graph construction* Smuggle inlining heuristic options through cranelift flags* Remove old CLI flags* set tunables before settings* Only configure inlining options for cranelift in fuzzing List of files: /wasmtime-44.0.1/crates/fuzzing/src/generators/config.rs