Zubin pushed to branch ghc-9.12 at Glasgow Haskell Compiler / GHC Commits: d4489170 by Cheng Shao at 2025-11-21T15:50:36+01:00 rts: fix top handler closure type signatures This commit fixes the runIO/runNonIO closure type signatures in the RTS which should be extern StgClosure. This allows us to remove an unnecessary type cast in the C foreign desugaring logic, as well as unneeded complications of JSFFI desugaring logic that also needs to generate C stubs that may refer to those top handler closures. Otherwise, we'll have to take special care to avoid generating "extern StgClosure" declarations for them as we would for other closures, just to avoid conflicting type signature error at stub compile time. (cherry picked from commit c78d8f55afacfd559b1602bc2fbc35b1f326f1c1) - - - - - 18d6cf11 by Cheng Shao at 2025-11-21T15:50:36+01:00 compiler: allow arbitrary label string for JSFFI exports This commit allows arbitrary label string to appear in a foreign export declaration, as long as the calling convention is javascript. Well, doesn't make sense to enforce it's a C function symbol for a JSFFI declaration anyway, and it gets in the way of implementing the "sync" flavour of exports. (cherry picked from commit a204df3aa5a7be00c67aa7c92c5091ab32522226) - - - - - 3ecb5e0b by Cheng Shao at 2025-11-21T15:50:36+01:00 compiler: wasm backend JSFFI sync exports This commit implements the synchronous flavour of the wasm backend JSFFI exports: - `foreign export javascript "foo sync"` exports a top-level Haskell binding as a synchronous JS function - `foreign import javascript "wrapper sync"` dynamically exports a Haskell function closure as a synchronous JS function - `foreign import javascript unsafe` is now re-entrant by lowering to a safe ccall - Also fix the issue that JSFFI dynamic exports didn't really work in TH & ghci (#25473) (cherry picked from commit 03ebab52bd00d4726735829cf6a24e5c9d3ac0c1) - - - - - 5afe9c33 by Cheng Shao at 2025-11-21T15:50:36+01:00 testsuite: test wasm backend JSFFI sync exports This commit repurposes some existing JSFFI test cases to make them cover JSFFI sync exports as well. (cherry picked from commit b6ae908bd3ae7b75b79925e56c3e11ba5c40b5ec) - - - - - 9efbf3f4 by Cheng Shao at 2025-11-21T15:50:37+01:00 docs: document wasm backend JSFFI sync exports This commit updates wasm backend documentation to reflect the new JSFFI sync exports feature. (cherry picked from commit edae287402792c09fa92b655e0cbd01100db9856) - - - - - 61754416 by Cheng Shao at 2025-11-21T15:50:37+01:00 wasm: add error message to WouldBlockException This commit attaches an error message to WouldBlockException, for now the error message consists of the JS async import code snippet that thunk is trying to block for. This is useful for debugging synchronous callbacks that accidentally call an async JS function. (cherry picked from commit 9b54eecbee7329543e5016cec1574831bfb788c2) - - - - - 3b26d306 by Cheng Shao at 2025-11-21T15:50:37+01:00 ghc-experimental: make JSVal abstract in GHC.Wasm.Prim This commit makes JSVal an abstract type in the export list of GHC.Wasm.Prim. JSVal's internal representation is supposed to be a non user facing implementation detail subject to change at any time. We should only expose things that are newtypes of JSVal, not JSVal itself. (cherry picked from commit 8037f487ff1721973737b01e29136c671fd25157) - - - - - 03600749 by Cheng Shao at 2025-11-21T15:50:37+01:00 wasm: make JSVal internal Weak# point to lifted JSVal JSVal has an internal Weak# with the unlifted JSVal# object as key to arrange its builtin finalization logic. The Weak# used to designate Unit_closure as a dummy value; now this commit designates the lifted JSVal closure as the Weak# value. This allows the implementation of mkWeakJSVal which can be used to observe the liveliness of a JSVal and attach a user-specified finalizer. (cherry picked from commit 4f34243101684a0ad15f5986abec00c675b48955) - - - - - f66e52c8 by Cheng Shao at 2025-11-21T15:50:37+01:00 ghc-experimental: add mkWeakJSVal This commit adds a mkWeakJSVal function that can be used to set up a Weak pointer with a JSVal key to observe the key's lifetime and optionally attach a finalizer. (cherry picked from commit 55af20e6ed5c72a46a09b88e8590b6b2309eb41b) - - - - - da0ccd0e by Cheng Shao at 2025-11-21T15:50:37+01:00 wasm: don't create a wasm global for dyld poison There's a much more efficient way to convert an unsigned i32 to a signed one. Thanks, o3-mini-high. (cherry picked from commit 75fcc5c9ab900cb80834802c581283681cf8c398) - - - - - 8003474f by Cheng Shao at 2025-11-21T16:01:18+01:00 wasm: revamp JSFFI internal implementation and documentation This patch revamps the wasm backend's JSFFI internal implementation and documentation: - `JSValManager` logic to allocate a key is simplified to simple bumping. According to experiments with all major browsers, the internal `Map` would overflow the heap much earlier before we really exhaust the 32-bit key space, so there's no point in the extra complexity. - `freeJSVal` is now idempotent and safe to call more than once. This is achieved by attaching the `StablePtr#` to the `JSVal#` closure and nullifying it when calling `freeJSVal`, so the same stable pointer cannot be double freed. - `mkWeakJSVal` no longer exposes the internal `Weak#` pointer and always creates a new `Weak#` on the fly. Otherwise by finalizing that `Weak#`, user could accidentally drop the `JSVal`, but `mkWeakJSVal` is only supposed to create a `Weak` that observes the `JSVal`'s liveliness without actually interfering it. - `PromisePendingException` is no longer exported since it's never meant to be caught by user code; it's a severe bug if it's actually raised at runtime. - Everything exported by user-facing `GHC.Wasm.Prim` now has proper haddock documentation. - Note [JSVal representation for wasm] has been updated to reflect the new JSVal# memory layout. (cherry picked from commit fd40eaa17c6ce8716ec2eacc95beae194a935352) - - - - - 60acee61 by Cheng Shao at 2025-11-21T16:03:36+01:00 rts: add hs_try_putmvar_with_value to RTS API This commit adds hs_try_putmvar_with_value to rts. It allows more flexibility than hs_try_putmvar by taking an additional value argument as a closure to be put into the MVar. This function is used & tested by the wasm backend runtime, though it makes sense to expose it as a public facing RTS API function as well. (cherry picked from commit f75e823e0a9ac9fbe661fce232324c5b103ee8a8) - - - - - cdfb37c3 by Cheng Shao at 2025-11-21T16:03:36+01:00 wasm: use MVar as JSFFI import blocking mechanism Previously, when blocking on a JSFFI import, we push a custom stg_jsffi_block stack frame and arrange the `promise.then` callback to write to that stack frame. It turns out we can simply use the good old MVar to implement the blocking logic, with a few benefits: - Less maintenance burden. We can drop the stg_jsffi_block related Cmm code without loss of functionality. - It interacts better with existing async exception mechanism. throwTo would properly block the caller if the target thread is masking async exceptions. (cherry picked from commit 9cd9f34787b4d54e1ba3fbbf927a160a0f8eab99) - - - - - 8dfb64de by Cheng Shao at 2025-11-21T16:03:36+01:00 wasm: properly pin the raiseJSException closure We used to use keepAlive# to pin the raiseJSException closure when blocking on a JSFFI import thunk, since it can potentially be used by RTS. But raiseJSException may be used in other places as well (e.g. the promise.throwTo logic), and it's better to simply unconditionally pin it in the JSFFI initialization logic. (cherry picked from commit da34f0aa2082d1c5a306cc8356abba15f3d59aad) - - - - - 0166eb5d by Cheng Shao at 2025-11-21T16:03:36+01:00 wasm: implement promise.throwTo() for async JSFFI exports This commit implements promise.throwTo() for wasm backend JSFFI exports. This allows the JavaScript side to interrupt Haskell computation by raising an async exception. See subsequent docs/test commits for more details. (cherry picked from commit dc904bfdd17ed1108580367b34bbe7204ed4ea95) - - - - - 93de375e by Cheng Shao at 2025-11-21T16:03:36+01:00 testsuite: add test for wasm promise.throwTo() logic This commit adds a test case to test the wasm backend promise.throwTo() logic. (cherry picked from commit 7f80455ee45e70d142bbc69478b9a8db43082187) - - - - - 791ac161 by Cheng Shao at 2025-11-21T16:03:36+01:00 docs: document the wasm backend promise.throwTo() feature (cherry picked from commit afdd3fe7fff60e046f6a3ee4795c58abe81f03a2) - - - - - 8d8807f2 by Cheng Shao at 2025-11-21T16:24:59+01:00 rts: fix wasm JSFFI initialization constructor code This commit fixes wasm JSFFI initialization constructor code so that the constructor is self-contained and avoids invoking a fake __main_argc_argv function. The previous approach of reusing __main_void logic in wasi-libc saves a tiny bit of code, at the expense of link-time trouble whenever GHC links a wasm module without -no-hs-main, in which case the driver-generated main function would clash with the definition here, resulting in a linker error. It's simply better to avoid messing with the main function, and it would additionally allow linking wasm32-wasi command modules that does make use of synchronous JSFFI. (cherry picked from commit bdc9d130a838017f863f5c7a380cb0858035f859) - - - - - 6d38b32c by Cheng Shao at 2025-11-21T17:16:11+01:00 wasm: fix remaining regressions in upstream 9.12 branch This commit fixes remaining regressions in upstream 9.12 branch caused by broken backporting of !14892. Fixes #26600. - - - - - 3cd27895 by Cheng Shao at 2025-11-25T14:30:05+01:00 docs: add wasm related items in 9.12.3 notes - - - - - 31 changed files: - compiler/GHC/HsToCore/Foreign/C.hs - compiler/GHC/HsToCore/Foreign/Wasm.hs - compiler/GHC/Tc/Gen/Foreign.hs - docs/users_guide/9.12.3-notes.rst - docs/users_guide/exts/ffi.rst - docs/users_guide/wasm.rst - libraries/ghc-experimental/src/GHC/Wasm/Prim.hs - libraries/ghc-internal/src/GHC/Internal/Wasm/Prim.hs - libraries/ghc-internal/src/GHC/Internal/Wasm/Prim/Exports.hs - libraries/ghc-internal/src/GHC/Internal/Wasm/Prim/Flag.hs - libraries/ghc-internal/src/GHC/Internal/Wasm/Prim/Imports.hs - libraries/ghc-internal/src/GHC/Internal/Wasm/Prim/Types.hs - rts/RtsAPI.c - rts/RtsSymbols.c - rts/include/HsFFI.h - rts/wasm/JSFFI.c - rts/wasm/blocker.cmm - rts/wasm/jsval.cmm - rts/wasm/scheduler.cmm - testsuite/tests/jsffi/all.T - + testsuite/tests/jsffi/cancel.hs - + testsuite/tests/jsffi/cancel.mjs - + testsuite/tests/jsffi/cancel.stdout - testsuite/tests/jsffi/jsffigc.hs - testsuite/tests/jsffi/jsffigc.mjs - testsuite/tests/jsffi/jsffisleep.hs - testsuite/tests/jsffi/jsffisleep.stdout - testsuite/tests/jsffi/textconv.hs - testsuite/tests/jsffi/textconv.mjs - utils/jsffi/dyld.mjs - utils/jsffi/prelude.mjs The diff was not included because it is too large. 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