[webkit-changes] [WebKit/WebKit] c95abf: [JSC] Wasm-GC: Struct members should have their na...

[jjgriego]

  Branch: refs/heads/main
  Home:   https://github.com/WebKit/WebKit
  Commit: c95abf8658bed1f7efac061995e591f8cff43b90
      https://github.com/WebKit/WebKit/commit/c95abf8658bed1f7efac061995e591f8cff43b90
  Author: Joseph Griego <jgriego at igalia.com>
  Date:   2023-11-27 (Mon, 27 Nov 2023)

  Changed paths:
    M Source/JavaScriptCore/wasm/WasmTypeDefinition.cpp
    M Source/JavaScriptCore/wasm/WasmTypeDefinition.h

  Log Message:
  -----------
  [JSC] Wasm-GC: Struct members should have their natural alignment
https://bugs.webkit.org/show_bug.cgi?id=265322

Reviewed by Justin Michaud.

For 32-bit concurrent JIT (and also for concurrent GC on 64-bit, AIUI), we need
members of these structs that are refs to be 8-byte aligned (for 64-bit atomic
access and to avoid spanning cache lines respectively); also, for performance
reasons, it's probably also good to have the scalar types aligned, anyways.

* Source/JavaScriptCore/wasm/WasmTypeDefinition.cpp:
(JSC::Wasm::StructType::StructType):
* Source/JavaScriptCore/wasm/WasmTypeDefinition.h:
(JSC::Wasm::typeAlignmentInBytes):

Canonical link: https://commits.webkit.org/271146@main