Changeset 52028 in webkit for trunk/JavaScriptCore/bytecode

Timestamp:

Dec 11, 2009, 3:34:10 PM (15 years ago)

Author:

[email protected]

Message:

​https://bugs.webkit.org/show_bug.cgi?id=32454
Refactor construction of simple strings to avoid string concatenation.

Reviewed by Oliver Hunt.

Building strings through concatenation has a memory and performance cost -
a memory cost since we must over-allocate the buffer to leave space to append
into, and performance in that the string may still require reallocation (and
thus copying during construction). Instead move the full construction to
within a single function call (makeString), so that the arguments' lengths
can be calculated and an appropriate sized buffer allocated before copying
any characters.

~No performance change (~2% progression on date tests).

• bytecode/CodeBlock.cpp:

(JSC::escapeQuotes):
(JSC::valueToSourceString):
(JSC::constantName):
(JSC::idName):
(JSC::CodeBlock::registerName):
(JSC::regexpToSourceString):
(JSC::regexpName):

• bytecompiler/NodesCodegen.cpp:

(JSC::substitute):

• profiler/Profiler.cpp:

(JSC::Profiler::createCallIdentifier):

• runtime/DateConstructor.cpp:

(JSC::callDate):

• runtime/DateConversion.cpp:

(JSC::formatDate):
(JSC::formatDateUTCVariant):
(JSC::formatTime):
(JSC::formatTimeUTC):

• runtime/DateConversion.h:

(JSC::):

• runtime/DatePrototype.cpp:

(JSC::dateProtoFuncToString):
(JSC::dateProtoFuncToUTCString):
(JSC::dateProtoFuncToDateString):
(JSC::dateProtoFuncToTimeString):
(JSC::dateProtoFuncToGMTString):

• runtime/ErrorPrototype.cpp:

(JSC::errorProtoFuncToString):

• runtime/ExceptionHelpers.cpp:

(JSC::createUndefinedVariableError):
(JSC::createErrorMessage):
(JSC::createInvalidParamError):

• runtime/FunctionPrototype.cpp:

(JSC::insertSemicolonIfNeeded):
(JSC::functionProtoFuncToString):

• runtime/ObjectPrototype.cpp:

(JSC::objectProtoFuncToString):

• runtime/RegExpConstructor.cpp:

(JSC::constructRegExp):

• runtime/RegExpObject.cpp:

(JSC::RegExpObject::match):

• runtime/RegExpPrototype.cpp:

(JSC::regExpProtoFuncCompile):
(JSC::regExpProtoFuncToString):

• runtime/StringPrototype.cpp:

(JSC::stringProtoFuncBig):
(JSC::stringProtoFuncSmall):
(JSC::stringProtoFuncBlink):
(JSC::stringProtoFuncBold):
(JSC::stringProtoFuncFixed):
(JSC::stringProtoFuncItalics):
(JSC::stringProtoFuncStrike):
(JSC::stringProtoFuncSub):
(JSC::stringProtoFuncSup):
(JSC::stringProtoFuncFontcolor):
(JSC::stringProtoFuncFontsize):
(JSC::stringProtoFuncAnchor):

• runtime/UString.h:

(JSC::):
(JSC::makeString):

File:

• trunk/JavaScriptCore/bytecode/CodeBlock.cpp (modified) (4 diffs)

trunk/JavaScriptCore/bytecode/CodeBlock.cpp

@@ -52 +52 @@
     int pos = 0;
     while ((pos = result.find('\"', pos)) >= 0) {
-        result = result.substr(0, pos) + "\"\\\"\"" + result.substr(pos + 1);
+        result = makeString(result.substr(0, pos), "\"\\\"\"", result.substr(pos + 1));
         pos += 4;
     }
@@ -63 +63 @@
         return "0";
 
-    if (val.isString()) {
-        UString result("\"");
-        result += escapeQuotes(val.toString(exec)) + "\"";
-        return result;
-    } 
+    if (val.isString())
+        return makeString("\"", escapeQuotes(val.toString(exec)), "\"");
 
     return val.toString(exec);
@@ -74 +71 @@
 static CString constantName(ExecState* exec, int k, JSValue value)
 {
-    return (valueToSourceString(exec, value) + "(@k" + UString::from(k - FirstConstantRegisterIndex) + ")").UTF8String();
+    return makeString(valueToSourceString(exec, value), "(@k", UString::from(k - FirstConstantRegisterIndex), ")").UTF8String();
 }
 
 static CString idName(int id0, const Identifier& ident)
 {
-    return (ident.ustring() + "(@id" + UString::from(id0) +")").UTF8String();
+    return makeString(ident.ustring(), "(@id", UString::from(id0), ")").UTF8String();
 }
 
@@ -90 +87 @@
         return constantName(exec, r, getConstant(r));
 
-    return (UString("r") + UString::from(r)).UTF8String();
+    return makeString("r", UString::from(r)).UTF8String();
 }
 
 static UString regexpToSourceString(RegExp* regExp)
 {
-    UString pattern = UString("/") + regExp->pattern() + "/";
+    char postfix[5] = { '/', 0, 0, 0, 0 };
+    int index = 1;
     if (regExp->global())
-        pattern += "g";
+        postfix[index++] = 'g';
     if (regExp->ignoreCase())
-        pattern += "i";
+        postfix[index++] = 'i';
     if (regExp->multiline())
-        pattern += "m";
-
-    return pattern;
+        postfix[index] = 'm';
+
+    return makeString("/", regExp->pattern(), postfix);
 }
 
 static CString regexpName(int re, RegExp* regexp)
 {
-    return (regexpToSourceString(regexp) + "(@re" + UString::from(re) + ")").UTF8String();
+    return makeString(regexpToSourceString(regexp), "(@re", UString::from(re), ")").UTF8String();
 }