Changeset 97872 in webkit for trunk/Source/JavaScriptCore/runtime/JSString.h

Timestamp:

Oct 19, 2011, 12:45:35 PM (14 years ago)

Author:

[email protected]

Message:

Some rope cleanup following r97827
​https://bugs.webkit.org/show_bug.cgi?id=70398

Reviewed by Oliver Hunt.

9% speedup on date-format-xparb, neutral overall.

• Removed RopeImpl*.
• Removed JSString::m_fiberCount, since this can be deduced from other data.
• Renamed a jsString() variant to jsStringFromArguments for clarity.

• CMakeLists.txt:
• GNUmakefile.list.am:
• JavaScriptCore.order:
• JavaScriptCore.pro:
• JavaScriptCore.vcproj/JavaScriptCore/JavaScriptCore.vcproj:
• JavaScriptCore.xcodeproj/project.pbxproj: Removed RopeImpl*.

• dfg/DFGSpeculativeJIT.cpp:

(JSC::DFG::SpeculativeJIT::compileGetCharCodeAt):
(JSC::DFG::SpeculativeJIT::compileGetByValOnString):

• jit/JITInlineMethods.h:

(JSC::JIT::emitLoadCharacterString):

• jit/JITPropertyAccess.cpp:

(JSC::JIT::stringGetByValStubGenerator):

• jit/JITPropertyAccess32_64.cpp:

(JSC::JIT::stringGetByValStubGenerator):

• jit/SpecializedThunkJIT.h:

(JSC::SpecializedThunkJIT::loadJSStringArgument):

• jit/ThunkGenerators.cpp:

(JSC::stringCharLoad): Use a NULL m_value to signal rope-iness, instead
of testing m_fiberCount, since m_fiberCount is gone now.

• runtime/JSString.cpp:

(JSC::JSString::RopeBuilder::expand):
(JSC::JSString::visitChildren):
(JSC::JSString::resolveRope):
(JSC::JSString::resolveRopeSlowCase):
(JSC::JSString::outOfMemory): Use a NULL fiber to indicate "last fiber
in the vector" instead of testing m_fiberCount, since m_fiberCount is gone now.

• runtime/JSString.h:

(JSC::RopeBuilder::JSString):
(JSC::RopeBuilder::finishCreation):
(JSC::RopeBuilder::offsetOfLength):
(JSC::RopeBuilder::isRope):
(JSC::RopeBuilder::string): Removed m_fiberCount. Renamed
jsString => jsStringFromArguments for clarity.

• runtime/Operations.h:

(JSC::jsStringFromArguments): Renamed.

• runtime/RopeImpl.cpp: Removed.
• runtime/RopeImpl.h: Removed.

• runtime/SmallStrings.cpp:

(JSC::SmallStrings::createEmptyString): Switched to StringImpl::empty,
which is slightly faster.

• runtime/StringPrototype.cpp:

(JSC::stringProtoFuncConcat): Updated for rename.

• wtf/text/StringImplBase.h:

(WTF::StringImplBase::StringImplBase): Removed the concept of an invalid
StringImpl, since this was only used by RopeImpl, which is now gone.

File:

• trunk/Source/JavaScriptCore/runtime/JSString.h (modified) (11 diffs)

trunk/Source/JavaScriptCore/runtime/JSString.h

@@ -29 +29 @@
 #include "PropertyDescriptor.h"
 #include "PropertySlot.h"
-#include "RopeImpl.h"
 #include "Structure.h"
 
@@ -77 +76 @@
                 : m_globalData(globalData)
                 , m_jsString(jsStringBuilder(&globalData))
+                , m_index(0)
             {
             }
@@ -82 +82 @@
             void append(JSString* jsString)
             {
-                if (m_jsString->m_fiberCount == JSString::s_maxInternalRopeLength)
+                if (m_index == JSString::s_maxInternalRopeLength)
                     expand();
-                m_jsString->m_fibers[m_jsString->m_fiberCount].set(m_globalData, m_jsString, jsString);
-                m_jsString->m_fiberCount += 1;
+                m_jsString->m_fibers[m_index++].set(m_globalData, m_jsString, jsString);
                 m_jsString->m_length += jsString->m_length;
             }
@@ -103 +102 @@
             JSGlobalData& m_globalData;
             JSString* m_jsString;
+            size_t m_index;
         };
 
@@ -109 +109 @@
             : JSCell(globalData, globalData.stringStructure.get())
             , m_value(value)
-            , m_fiberCount(0)
         {
         }
@@ -115 +114 @@
         JSString(JSGlobalData& globalData)
             : JSCell(globalData, globalData.stringStructure.get())
-            , m_fiberCount(0)
         {
         }
@@ -144 +142 @@
             Base::finishCreation(globalData);
             m_length = s1->length() + s2->length();
-            m_fiberCount = 2;
             m_fibers[0].set(globalData, this, s1);
             m_fibers[1].set(globalData, this, s2);
@@ -153 +150 @@
             Base::finishCreation(globalData);
             m_length = s1->length() + s2->length() + s3->length();
-            m_fiberCount = 3;
             m_fibers[0].set(globalData, this, s1);
             m_fibers[1].set(globalData, this, s2);
@@ -236 +232 @@
 
         static size_t offsetOfLength() { return OBJECT_OFFSETOF(JSString, m_length); }
-        static size_t offsetOfFiberCount() { return OBJECT_OFFSETOF(JSString, m_fiberCount); }
         static size_t offsetOfValue() { return OBJECT_OFFSETOF(JSString, m_value); }
 
@@ -246 +241 @@
         JSString(VPtrStealingHackType) 
             : JSCell(VPtrStealingHack)
-            , m_fiberCount(0)
         {
         }
@@ -265 +259 @@
         static const unsigned s_maxInternalRopeLength = 3;
 
-        // A string is represented either by a UString or a RopeImpl.
+        // A string is represented either by a UString or a rope of fibers.
         unsigned m_length;
         mutable UString m_value;
-        mutable unsigned m_fiberCount;
         mutable FixedArray<WriteBarrier<JSString>, s_maxInternalRopeLength> m_fibers;
 
-        bool isRope() const { return m_fiberCount; }
+        bool isRope() const { return m_value.isNull(); }
         UString& string() { ASSERT(!isRope()); return m_value; }
-        unsigned fiberCount() { return m_fiberCount ? m_fiberCount : 1; }
-
-        friend JSValue jsString(ExecState* exec, JSString* s1, JSString* s2);
-        friend JSValue jsString(ExecState* exec, Register* strings, unsigned count);
-        friend JSValue jsString(ExecState* exec, JSValue thisValue);
-        friend JSString* jsSubstring(ExecState* exec, JSString* s, unsigned offset, unsigned length);
+
+        friend JSValue jsString(ExecState*, JSString*, JSString*);
+        friend JSValue jsString(ExecState*, Register*, unsigned count);
+        friend JSValue jsStringFromArguments(ExecState*, JSValue thisValue);
+        friend JSString* jsSubstring(ExecState*, JSString*, unsigned offset, unsigned length);
     };