[webkit-changes] [WebKit/WebKit] b4d99e: [JSC] Extend megamorphic store cache with invalida...

[Yusuke Suzuki]

  Branch: refs/heads/main
  Home:   https://github.com/WebKit/WebKit
  Commit: b4d99e644e12f78fe4c1e71edea6aab37ead4450
      https://github.com/WebKit/WebKit/commit/b4d99e644e12f78fe4c1e71edea6aab37ead4450
  Author: Yusuke Suzuki <ysuzuki at apple.com>
  Date:   2023-05-18 (Thu, 18 May 2023)

  Changed paths:
    M Source/JavaScriptCore/bytecode/InlineCacheCompiler.cpp
    M Source/JavaScriptCore/jit/AssemblyHelpers.cpp
    M Source/JavaScriptCore/jit/JITOperations.cpp
    M Source/JavaScriptCore/runtime/Structure.cpp
    M Source/JavaScriptCore/runtime/Structure.h
    M Source/JavaScriptCore/runtime/StructureInlines.h

  Log Message:
  -----------
  [JSC] Extend megamorphic store cache with invalidating replacement watchpoint set
https://bugs.webkit.org/show_bug.cgi?id=256943
rdar://109493502

Reviewed by Justin Michaud.

This patch recovers regression in JetStream2/typescript after introducing megamorphic store cache.
The reason is that the previous cache was a bit too conservative, and we are using slow path for
Structure::isWatchingReplacement case, but JetStream2/typescript includes legit use of this kind of
Structure with megamorphic cache.
This patch allows Structure::isWatchingReplacement case, and invalidate replacement watchpoint when
caching replace structure. This recovers and rather improves JetStream2/typescript.

* Source/JavaScriptCore/bytecode/InlineCacheCompiler.cpp:
(JSC::InlineCacheCompiler::regenerate):
* Source/JavaScriptCore/jit/AssemblyHelpers.cpp:
(JSC::AssemblyHelpers::storeMegamorphicProperty):
* Source/JavaScriptCore/jit/JITOperations.cpp:
(JSC::putByIdMegamorphic):

Canonical link: https://commits.webkit.org/264212@main