From 25b3df3e21324465fefd9aed2cf3901cfd76a7c1 Mon Sep 17 00:00:00 2001 From: Daniel Ehrenberg Date: Mon, 18 Mar 2019 10:52:13 +0100 Subject: [PATCH] [jsapi] Normative: Always queue a task during asynchronous instantiation JSC will have to do asynchronous compilation work during some instantiations. To be consistent, this PR always queues a task to complete instantiation, except through the synchronous Instance(module) API, to ensure consistency across platforms. This patch also cleans up the specification in various surrounding ways: - Include notes about APIs whose use is discouraged/may be limited Closes #741 See also https://github.com/webpack/webpack/issues/6433 --- document/js-api/index.bs | 27 +++++++++++++++------------ 1 file changed, 15 insertions(+), 12 deletions(-) diff --git a/document/js-api/index.bs b/document/js-api/index.bs index 19600b85c4..19faf7ed0e 100644 --- a/document/js-api/index.bs +++ b/document/js-api/index.bs @@ -474,13 +474,15 @@ The verification of WebAssembly type requirements is deferred to the 1. Let |module| be |moduleObject|.\[[Module]]. 1. [=Read the imports=] of |module| with imports |importObject|, and let |imports| be the result. If this operation throws an exception, catch it, [=reject=] |promise| with the exception, and return |promise|. - 1. [=Queue a task=] to perform the following steps: - 1. [=Instantiate the core of a WebAssembly module=] |module| with |imports|, and let |instance| be the result. - If this throws an exception, catch it, [=reject=] |promise| with the exception, and terminate these substeps. - 1. Let |instanceObject| be a [=/new=] {{Instance}}. - 1. [=initialize an instance object|Initialize=] |instanceObject| from |module| and |instance|. - If this throws an exception, catch it, [=reject=] |promise| with the exception, and terminate these substeps. - 1. [=Resolve=] |promise| with |instanceObject|. + 1. Run the following steps [=in parallel=]: + 1. [=Queue a task=] to perform the following steps: + Note: Implementation-specific work may be performed here. + 1. [=Instantiate the core of a WebAssembly module=] |module| with |imports|, and let |instance| be the result. + If this throws an exception, catch it, [=reject=] |promise| with the exception, and terminate these substeps. + 1. Let |instanceObject| be a [=/new=] {{Instance}}. + 1. [=initialize an instance object|Initialize=] |instanceObject| from |module| and |instance|. + If this throws an exception, catch it, [=reject=] |promise| with the exception, and terminate these substeps. + 1. [=Resolve=] |promise| with |instanceObject|. 1. Return |promise|. @@ -499,14 +501,15 @@ The verification of WebAssembly type requirements is deferred to the 1. Let |promise| be [=a new promise=]. 1. [=Upon fulfillment=] of |promiseOfModule| with value |module|: - 1. [=synchronously instantiate a WebAssembly module|Synchronously instantiate the WebAssembly module=] |module| importing |importObject|, and let |instance| be the result. If this throws an exception, catch it, [=reject=] |promise| with the exception, and abort these substeps. - 1. Let |result| be the {{WebAssemblyInstantiatedSource}} value «[ "{{WebAssemblyInstantiatedSource/module}}" → |module|, "{{WebAssemblyInstantiatedSource/instance}}" → |instance| ]». - 1. [=Resolve=] |promise| with |result|. + 1. [=asynchronously instantiate a WebAssembly module|Instantiate the WebAssembly module=] |module| importing |importObject|, and let |innerPromise| be the result. + 1. [=Upon fulfillment=] of |innerPromise| with value |instance|. + 1. Let |result| be the {{WebAssemblyInstantiatedSource}} value «[ "{{WebAssemblyInstantiatedSource/module}}" → |module|, "{{WebAssemblyInstantiatedSource/instance}}" → |instance| ]». + 1. [=Resolve=] |promise| with |result|. + 1. [=Upon rejection=] of |innerPromise| with reason |reason|: + 1. [=Reject=] |promise| with |reason|. 1. [=Upon rejection=] of |promiseOfModule| with reason |reason|: 1. [=Reject=] |promise| with |reason|. 1. Return |promise|. - - Note: It would be valid to perform certain parts of the instantiation [=in parallel=], but several parts need to happen in the event loop, including JavaScript operations to access the |importObject| and execution of the start function.