Title: [292327] branches/safari-613-branch/Source/_javascript_Core/runtime
- Revision
- 292327
- Author
- alanc...@apple.com
- Date
- 2022-04-04 14:55:22 -0700 (Mon, 04 Apr 2022)
Log Message
Cherry-pick r289177. rdar://91259284
Cache the most recent AtomString produced by JSString::toIdentifier
https://bugs.webkit.org/show_bug.cgi?id=236124
Reviewed by Yusuke Suzuki.
JSString::toIdentifier does not store the result of atomizing its string
value, except when it is a rope. We can often end up atomizing the same
JSString a number of times.
This patch caches the last atomized string produced from
JSString::toIdentifier in a given VM. From local testing, this is a 0.5%
Speedometer2 improvement on an M1 MacBook Air, although surprisingly is
neutral on a recent Intel MacBook Pro.
runtime/JSString.h:
(JSC::JSRopeString::toIdentifier const):
(JSC::JSString::toIdentifier const):
runtime/VM.h:
Modified Paths
Diff
Modified: branches/safari-613-branch/Source/_javascript_Core/runtime/JSString.h (292326 => 292327)
--- branches/safari-613-branch/Source/_javascript_Core/runtime/JSString.h 2022-04-04 21:55:19 UTC (rev 292326)
+++ branches/safari-613-branch/Source/_javascript_Core/runtime/JSString.h 2022-04-04 21:55:22 UTC (rev 292327)
@@ -602,6 +602,7 @@
JS_EXPORT_PRIVATE RefPtr<AtomStringImpl> resolveRopeToExistingAtomString(JSGlobalObject*) const;
template<typename CharacterType> NEVER_INLINE void resolveRopeSlowCase(CharacterType*) const;
template<typename CharacterType> void resolveRopeInternalNoSubstring(CharacterType*) const;
+ Identifier toIdentifier(JSGlobalObject*) const;
void outOfMemory(JSGlobalObject* nullOrGlobalObjectForOOM) const;
void resolveRopeInternal8(LChar*) const;
void resolveRopeInternal16(UChar*) const;
@@ -759,15 +760,31 @@
return JSString::create(vm, s.releaseImpl().releaseNonNull());
}
-ALWAYS_INLINE Identifier JSString::toIdentifier(JSGlobalObject* globalObject) const
+ALWAYS_INLINE Identifier JSRopeString::toIdentifier(JSGlobalObject* globalObject) const
{
VM& vm = getVM(globalObject);
auto scope = DECLARE_THROW_SCOPE(vm);
- AtomString atomString = toAtomString(globalObject);
+ auto atomString = static_cast<const JSRopeString*>(this)->resolveRopeToAtomString(globalObject);
RETURN_IF_EXCEPTION(scope, { });
return Identifier::fromString(vm, atomString);
}
+ALWAYS_INLINE Identifier JSString::toIdentifier(JSGlobalObject* globalObject) const
+{
+ if constexpr (validateDFGDoesGC)
+ vm().verifyCanGC();
+ if (isRope())
+ return static_cast<const JSRopeString*>(this)->toIdentifier(globalObject);
+ VM& vm = getVM(globalObject);
+ if (valueInternal().impl()->isAtom())
+ return Identifier::fromString(vm, Ref { *static_cast<AtomStringImpl*>(valueInternal().impl()) });
+ if (vm.lastAtomizedIdentifierStringImpl.ptr() != valueInternal().impl()) {
+ vm.lastAtomizedIdentifierStringImpl = *valueInternal().impl();
+ vm.lastAtomizedIdentifierAtomStringImpl = AtomStringImpl::add(valueInternal().impl()).releaseNonNull();
+ }
+ return Identifier::fromString(vm, Ref { vm.lastAtomizedIdentifierAtomStringImpl });
+}
+
ALWAYS_INLINE AtomString JSString::toAtomString(JSGlobalObject* globalObject) const
{
if constexpr (validateDFGDoesGC)
Modified: branches/safari-613-branch/Source/_javascript_Core/runtime/VM.h (292326 => 292327)
--- branches/safari-613-branch/Source/_javascript_Core/runtime/VM.h 2022-04-04 21:55:19 UTC (rev 292326)
+++ branches/safari-613-branch/Source/_javascript_Core/runtime/VM.h 2022-04-04 21:55:22 UTC (rev 292327)
@@ -586,6 +586,8 @@
NumericStrings numericStrings;
std::unique_ptr<SimpleStats> machineCodeBytesPerBytecodeWordForBaselineJIT;
Strong<JSString> lastCachedString;
+ Ref<StringImpl> lastAtomizedIdentifierStringImpl { *StringImpl::empty() };
+ Ref<AtomStringImpl> lastAtomizedIdentifierAtomStringImpl { *static_cast<AtomStringImpl*>(StringImpl::empty()) };
JSONAtomStringCache jsonAtomStringCache;
AtomStringTable* atomStringTable() const { return m_atomStringTable; }
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