Attachment 361375 Details for Bug 194374 – Patch

[patch] Patch

bug-194374-20190206205930.patch (text/plain), 4.00 KB, created by Yusuke Suzuki on 2019-02-06 20:59:30 PST

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Creator: Yusuke Suzuki

Created: 2019-02-06 20:59:30 PST

Size: 4.00 KB

patch

obsolete

>Subversion Revision: 241114
>diff --git a/Source/JavaScriptCore/ChangeLog b/Source/JavaScriptCore/ChangeLog
>index 9ca525e7f7b1f02d723cf095ae71c5933e011227..97d5bdd9d86c634ddc2f76bebe2df26ef5ff86c9 100644
>--- a/Source/JavaScriptCore/ChangeLog
>+++ b/Source/JavaScriptCore/ChangeLog
>@@ -1,3 +1,19 @@
>+2019-02-06  Yusuke Suzuki  <ysuzuki@apple.com>
>+
>+        [JSC] Use BufferInternal single character StringImpl for SmallStrings
>+        https://bugs.webkit.org/show_bug.cgi?id=194374
>+
>+        Reviewed by NOBODY (OOPS!).
>+
>+        Currently, we first create a large StringImpl, and create bunch of substrings with length = 1.
>+        But pointer is larger than single character. BufferInternal StringImpl with single character
>+        is more memory efficient.
>+
>+        * runtime/SmallStrings.cpp:
>+        (JSC::SmallStringsStorage::SmallStringsStorage):
>+        (JSC::SmallStrings::SmallStrings):
>+        * runtime/SmallStrings.h:
>+
> 2019-02-06  Yusuke Suzuki  <ysuzuki@apple.com>
> 
>         [JSC] InitializeEntrypointArguments should produce SpecCellCheck if FlushFormat is FlushedCell
>diff --git a/Source/JavaScriptCore/runtime/SmallStrings.cpp b/Source/JavaScriptCore/runtime/SmallStrings.cpp
>index 60e21b6cf46e13e462358448ff28b7da91422fce..8f26b3e1e2a164e7f3c3347287c0f4e33734747f 100644
>--- a/Source/JavaScriptCore/runtime/SmallStrings.cpp
>+++ b/Source/JavaScriptCore/runtime/SmallStrings.cpp
>@@ -52,28 +52,18 @@ class SmallStringsStorage {
> 
> SmallStringsStorage::SmallStringsStorage()
> {
>-    LChar* characterBuffer = 0;
>-    auto baseString = StringImpl::createUninitialized(singleCharacterStringCount, characterBuffer);
>     for (unsigned i = 0; i < singleCharacterStringCount; ++i) {
>-        characterBuffer[i] = i;
>-        m_reps[i] = AtomicStringImpl::add(StringImpl::createSubstringSharingImpl(baseString.get(), i, 1).ptr());
>+        const LChar string[] = { static_cast<LChar>(i) };
>+        m_reps[i] = AtomicStringImpl::add(StringImpl::create(string, 1).ptr());
>     }
> }
> 
> SmallStrings::SmallStrings()
>-    : m_emptyString(0)
>-#define JSC_COMMON_STRINGS_ATTRIBUTE_INITIALIZE(name) , m_##name(0)
>-    JSC_COMMON_STRINGS_EACH_NAME(JSC_COMMON_STRINGS_ATTRIBUTE_INITIALIZE)
>-#undef JSC_COMMON_STRINGS_ATTRIBUTE_INITIALIZE
>-    , m_objectStringStart(nullptr)
>-    , m_nullObjectString(nullptr)
>-    , m_undefinedObjectString(nullptr)
>-    , m_needsToBeVisited(true)
> {
>     COMPILE_ASSERT(singleCharacterStringCount == sizeof(m_singleCharacterStrings) / sizeof(m_singleCharacterStrings[0]), IsNumCharactersConstInSyncWithClassUsage);
> 
>     for (unsigned i = 0; i < singleCharacterStringCount; ++i)
>-        m_singleCharacterStrings[i] = 0;
>+        m_singleCharacterStrings[i] = nullptr;
> }
> 
> void SmallStrings::initializeCommonStrings(VM& vm)
>diff --git a/Source/JavaScriptCore/runtime/SmallStrings.h b/Source/JavaScriptCore/runtime/SmallStrings.h
>index 8850c4a9a34394f18f75a35d67ba3a45a19fe47e..769d494f320c403eff6f1539e22396f09cf83486 100644
>--- a/Source/JavaScriptCore/runtime/SmallStrings.h
>+++ b/Source/JavaScriptCore/runtime/SmallStrings.h
>@@ -131,16 +131,16 @@ class SmallStrings {
> 
>     void initialize(VM*, JSString*&, const char* value);
> 
>-    JSString* m_emptyString;
>-#define JSC_COMMON_STRINGS_ATTRIBUTE_DECLARATION(name) JSString* m_##name;
>+    JSString* m_emptyString { nullptr };
>+#define JSC_COMMON_STRINGS_ATTRIBUTE_DECLARATION(name) JSString* m_##name { nullptr };
>     JSC_COMMON_STRINGS_EACH_NAME(JSC_COMMON_STRINGS_ATTRIBUTE_DECLARATION)
> #undef JSC_COMMON_STRINGS_ATTRIBUTE_DECLARATION
>-    JSString* m_objectStringStart;
>-    JSString* m_nullObjectString;
>-    JSString* m_undefinedObjectString;
>-    JSString* m_singleCharacterStrings[singleCharacterStringCount];
>+    JSString* m_objectStringStart { nullptr };
>+    JSString* m_nullObjectString { nullptr };
>+    JSString* m_undefinedObjectString { nullptr };
>+    JSString* m_singleCharacterStrings[singleCharacterStringCount] { nullptr };
>     std::unique_ptr<SmallStringsStorage> m_storage;
>-    bool m_needsToBeVisited;
>+    bool m_needsToBeVisited { true };
> };
> 
> } // namespace JSC

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Attachments on bug 194374: 361375