Changeset 289515 in webkit for trunk/Source/JavaScriptCore/runtime/JSString.cpp

Timestamp:

Feb 9, 2022, 5:50:04 PM (3 years ago)

Author:

[email protected]

Message:

Use local variable pointer for concurrently load value
​https://bugs.webkit.org/show_bug.cgi?id=236387

Reviewed by Saam Barati.

Consistently using local pointer to load member fields in

1. WriteBarrierStructureID
2. JSString's fiber
3. Weak
4. WriteBarrier<SomeKindOfCell>

to encourage compilers not to load the field twice.

• heap/Weak.cpp:

(JSC::weakClearSlowCase):

• heap/Weak.h:

(JSC::Weak::isHashTableEmptyValue const):
(JSC::Weak::unsafeImpl const):
(JSC::Weak::clear):
(JSC::Weak::impl const):

• heap/WeakInlines.h:

(JSC::Weak<T>::isHashTableDeletedValue const):
(JSC:: const):
(JSC::Weak<T>::operator const):
(JSC::Weak<T>::get const):
(JSC::Weak<T>::leakImpl):

• runtime/JSString.cpp:

(JSC::JSString::dumpToStream):
(JSC::JSString::estimatedSize):
(JSC::JSString::visitChildrenImpl):

• runtime/JSString.h:

(JSC::JSString::fiberConcurrently const):
(JSC::JSString::is8Bit const):
(JSC::JSString::length const):
(JSC::JSString::tryGetValueImpl const):
(JSC::JSString::isSubstring const):

• runtime/WriteBarrier.h:

(JSC::WriteBarrierBase::get const):
(JSC::WriteBarrierBase::operator* const):
(JSC::WriteBarrierBase::operator-> const):
(JSC::WriteBarrierBase::operator bool const):
(JSC::WriteBarrierBase::operator! const):
(JSC::WriteBarrierBase::unvalidatedGet const):
(JSC::WriteBarrierBase::cell const):
(JSC::WriteBarrierStructureID::get const):
(JSC::WriteBarrierStructureID::operator* const):
(JSC::WriteBarrierStructureID::operator-> const):
(JSC::WriteBarrierStructureID::operator bool const):
(JSC::WriteBarrierStructureID::operator! const):
(JSC::WriteBarrierStructureID::unvalidatedGet const):

File:

• trunk/Source/JavaScriptCore/runtime/JSString.cpp (modified) (3 diffs)

trunk/Source/JavaScriptCore/runtime/JSString.cpp

@@ -69 +69 @@
     const JSString* thisObject = jsCast<const JSString*>(cell);
     out.printf("<%p, %s, [%u], ", thisObject, thisObject->className(vm), thisObject->length());
-    uintptr_t pointer = thisObject->m_fiber;
+    uintptr_t pointer = thisObject->fiberConcurrently();
     if (pointer & isRopeInPointer) {
         if (pointer & JSRopeString::isSubstringInPointer)
@@ -104 +104 @@
 {
     JSString* thisObject = asString(cell);
-    uintptr_t pointer = thisObject->m_fiber;
+    uintptr_t pointer = thisObject->fiberConcurrently();
     if (pointer & isRopeInPointer)
         return Base::estimatedSize(cell, vm);
@@ -117 +117 @@
     Base::visitChildren(thisObject, visitor);
     
-    uintptr_t pointer = thisObject->m_fiber;
+    uintptr_t pointer = thisObject->fiberConcurrently();
     if (pointer & isRopeInPointer) {
         if (pointer & JSRopeString::isSubstringInPointer) {