Branch: refs/heads/main
Home: https://github.com/WebKit/WebKit
Commit: 702a8c0f58a9cc1a99bab360867740121892661c
https://github.com/WebKit/WebKit/commit/702a8c0f58a9cc1a99bab360867740121892661c
Author: Keith Miller <keith_mil...@apple.com>
Date: 2024-11-12 (Tue, 12 Nov 2024)
Changed paths:
M Source/JavaScriptCore/runtime/NativeCalleeRegistry.h
M Source/JavaScriptCore/wasm/WasmCallee.cpp
M Source/JavaScriptCore/wasm/WasmCallee.h
M Source/WTF/wtf/Atomics.h
M Source/WTF/wtf/ThreadSafeWeakPtr.h
M Tools/TestWebKitAPI/Tests/WTF/WeakPtr.cpp
Log Message:
-----------
ThreadSafeRefCountedAndCanMakeThreadSafeWeakPtr should be optimized for the
case where most references are strong
https://bugs.webkit.org/show_bug.cgi?id=282623
rdar://139297882
Reviewed by Justin Michaud.
This patch optimizes ThreadSafeRefCountedAndCanMakeThreadSafeWeakPtr for the
case that the object is
only referenced strongly. This comes up a lot for Wasm::Callees as they're only
weakly referenced only
while they are awaiting destruction. To make this work, the pointer to the
ControlBlock is now logically
a `union { ControlBlock*; Atomic<uintptr_t> strongOnlyRefCountAndFlag }`.
In this new world it also no longer makes sense to take a WeakPtr to an object
during its destructor,
which IMO didn't really make sense before. The WeakPtr must report the object
as dead since the WeakPtr
doesn't realistically have a way to know if the new strong ref is coming from
the thread destroying the
object or not. This patch removes a test case ASSERTing this was possible.
Lastly, this patch moves m_index in Wasm::Callee above m_indexOrName since that
reduces padding, thus
Wasm::Callee is no bigger than it was before.
* Source/JavaScriptCore/runtime/NativeCalleeRegistry.h:
(JSC::NativeCalleeRegistry::registerCallee):
* Source/JavaScriptCore/wasm/WasmCallee.cpp:
(JSC::Wasm::Callee::Callee):
* Source/JavaScriptCore/wasm/WasmCallee.h:
* Source/WTF/wtf/Atomics.h:
(WTF::Atomic::transaction):
* Source/WTF/wtf/ThreadSafeWeakPtr.h:
(WTF::ThreadSafeWeakPtrControlBlock::ThreadSafeWeakPtrControlBlock):
(WTF::ThreadSafeRefCountedAndCanMakeThreadSafeWeakPtr::ref const):
(WTF::ThreadSafeRefCountedAndCanMakeThreadSafeWeakPtr::deref const):
(WTF::ThreadSafeRefCountedAndCanMakeThreadSafeWeakPtr::refCount const):
(WTF::ThreadSafeRefCountedAndCanMakeThreadSafeWeakPtr::hasOneRef const):
(WTF::ThreadSafeRefCountedAndCanMakeThreadSafeWeakPtr::controlBlock const):
(WTF::ThreadSafeRefCountedAndCanMakeThreadSafeWeakPtr::isStrongOnly):
* Tools/TestWebKitAPI/Tests/WTF/WeakPtr.cpp:
Canonical link: https://commits.webkit.org/286483@main
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