Title: [293768] trunk/Source/WTF
- Revision
- 293768
- Author
- ysuz...@apple.com
- Date
- 2022-05-04 02:30:16 -0700 (Wed, 04 May 2022)
Log Message
[WTF] Initialize emptyString and nullString data at compile time
https://bugs.webkit.org/show_bug.cgi?id=240054
Reviewed by Mark Lam.
As we did for AtomString in r293757, we can initialize emptyString() and nullString()
data at compile time. This patch does that for WTF::String.
* Source/WTF/wtf/text/WTFString.cpp:
(WTF::emptyString): Deleted.
(WTF::nullString): Deleted.
* Source/WTF/wtf/text/WTFString.h:
(WTF::StaticString::StaticString):
(WTF::nullString):
(WTF::emptyString):
Canonical link: https://commits.webkit.org/250247@main
Modified Paths
Diff
Modified: trunk/Source/WTF/ChangeLog (293767 => 293768)
--- trunk/Source/WTF/ChangeLog 2022-05-04 09:12:15 UTC (rev 293767)
+++ trunk/Source/WTF/ChangeLog 2022-05-04 09:30:16 UTC (rev 293768)
@@ -1,5 +1,23 @@
2022-05-03 Yusuke Suzuki <ysuz...@apple.com>
+ [WTF] Initialize emptyString and nullString data at compile time
+ https://bugs.webkit.org/show_bug.cgi?id=240054
+
+ Reviewed by Mark Lam.
+
+ As we did for AtomString in r293757, we can initialize emptyString() and nullString()
+ data at compile time. This patch does that for WTF::String.
+
+ * wtf/text/WTFString.cpp:
+ (WTF::emptyString): Deleted.
+ (WTF::nullString): Deleted.
+ * wtf/text/WTFString.h:
+ (WTF::StaticString::StaticString):
+ (WTF::nullString):
+ (WTF::emptyString):
+
+2022-05-03 Yusuke Suzuki <ysuz...@apple.com>
+
[JSC] Initialize empty and null AtomString at compile time
https://bugs.webkit.org/show_bug.cgi?id=240031
Modified: trunk/Source/WTF/wtf/text/WTFString.cpp (293767 => 293768)
--- trunk/Source/WTF/wtf/text/WTFString.cpp 2022-05-04 09:12:15 UTC (rev 293767)
+++ trunk/Source/WTF/wtf/text/WTFString.cpp 2022-05-04 09:30:16 UTC (rev 293768)
@@ -635,18 +635,9 @@
return static_cast<float>(toDoubleType<UChar, TrailingJunkPolicy::Allow>(data, length, nullptr, parsedLength));
}
-const String& emptyString()
-{
- static NeverDestroyed<String> emptyString(StringImpl::empty());
- return emptyString;
-}
+WTF_EXPORT_PRIVATE const StaticString nullStringData { nullptr };
+WTF_EXPORT_PRIVATE const StaticString emptyStringData { &StringImpl::s_emptyAtomString };
-const String& nullString()
-{
- static NeverDestroyed<String> nullString;
- return nullString;
-}
-
} // namespace WTF
#ifndef NDEBUG
Modified: trunk/Source/WTF/wtf/text/WTFString.h (293767 => 293768)
--- trunk/Source/WTF/wtf/text/WTFString.h 2022-05-04 09:12:15 UTC (rev 293767)
+++ trunk/Source/WTF/wtf/text/WTFString.h 2022-05-04 09:30:16 UTC (rev 293768)
@@ -380,9 +380,21 @@
template<typename CharacterType> void appendNumber(Vector<CharacterType>&, unsigned char number);
// Shared global empty and null string.
-WTF_EXPORT_PRIVATE const String& emptyString();
-WTF_EXPORT_PRIVATE const String& nullString();
+struct StaticString {
+ constexpr StaticString(StringImpl::StaticStringImpl* pointer)
+ : m_pointer(pointer)
+ {
+ }
+ StringImpl::StaticStringImpl* m_pointer;
+};
+static_assert(sizeof(String) == sizeof(StaticString), "String and StaticString must be the same size!");
+extern WTF_EXPORT_PRIVATE const StaticString nullStringData;
+extern WTF_EXPORT_PRIVATE const StaticString emptyStringData;
+
+inline const String& nullString() { return *reinterpret_cast<const String*>(&nullStringData); }
+inline const String& emptyString() { return *reinterpret_cast<const String*>(&emptyStringData); }
+
template<typename> struct DefaultHash;
template<> struct DefaultHash<String>;
template<> struct VectorTraits<String> : VectorTraitsBase<false, void> {
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