Some string optimizations:

src/macros.py

 # Copyright 2006-2009 the V8 project authors. All rights reserved.
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 #       notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
 #       copyright notice, this list of conditions and the following
 #       disclaimer in the documentation and/or other materials provided
@@ skipping 56 matching lines @@
 
 # Note: kDayZeroInJulianDay = ToJulianDay(1970, 0, 1).
 const kInvalidDate        = 'Invalid Date';
 const kDayZeroInJulianDay = 2440588;
 const kMonthMask          = 0x1e0;
 const kDayMask            = 0x01f;
 const kYearShift          = 9;
 const kMonthShift         = 5;
 
 # Type query macros.
+#
+# Note: We have special support for typeof(foo) === 'bar' in the compiler.
+#       It will *not* generate a runtime typeof call for the most important
+#       values of 'bar'.
 macro IS_NULL(arg)              = (arg === null);
 macro IS_NULL_OR_UNDEFINED(arg) = (arg == null);
 macro IS_UNDEFINED(arg)         = (typeof(arg) === 'undefined');
 macro IS_NUMBER(arg)            = (typeof(arg) === 'number');
 macro IS_STRING(arg)            = (typeof(arg) === 'string');
 macro IS_BOOLEAN(arg)           = (typeof(arg) === 'boolean');
 macro IS_OBJECT(arg)            = (%_IsObject(arg));
 macro IS_ARRAY(arg)             = (%_IsArray(arg));
 macro IS_FUNCTION(arg)          = (%_IsFunction(arg));
-macro IS_REGEXP(arg)            = (%_ClassOf(arg) === 'RegExp');
+macro IS_REGEXP(arg)            = (%_IsRegExp(arg));
 macro IS_DATE(arg)              = (%_ClassOf(arg) === 'Date');
 macro IS_NUMBER_WRAPPER(arg)    = (%_ClassOf(arg) === 'Number');
 macro IS_STRING_WRAPPER(arg)    = (%_ClassOf(arg) === 'String');
 macro IS_BOOLEAN_WRAPPER(arg)   = (%_ClassOf(arg) === 'Boolean');
 macro IS_ERROR(arg)             = (%_ClassOf(arg) === 'Error');
 macro IS_SCRIPT(arg)            = (%_ClassOf(arg) === 'Script');
 macro IS_ARGUMENTS(arg)         = (%_ClassOf(arg) === 'Arguments');
 macro IS_GLOBAL(arg)            = (%_ClassOf(arg) === 'global');
 macro IS_UNDETECTABLE(arg)      = (%_IsUndetectableObject(arg));
 macro FLOOR(arg)                = $floor(arg);
 
 # Inline macros. Use %IS_VAR to make sure arg is evaluated only once.
 macro NUMBER_IS_NAN(arg) = (!%_IsSmi(%IS_VAR(arg)) && !(arg == arg));
 macro TO_INTEGER(arg)    = (%_IsSmi(%IS_VAR(arg)) ? arg : ToInteger(arg));
 macro TO_INT32(arg)      = (%_IsSmi(%IS_VAR(arg)) ? arg : (arg >> 0));
 macro TO_UINT32(arg)     = (arg >>> 0);
+macro TO_STRING_INLINE(arg)     = (IS_STRING(%IS_VAR(arg)) ? arg : NonStringToString(arg));

[Mads Ager (chromium), 2010/02/19 09:56:29]

Remove extra spaces before '=' on this line.  I would be in favor of removing
all of the alignment whitespace here, but you don't have to do that in this
change.

[Vitaly Repeshko, 2010/02/19 13:12:35]

Done.

+
 
 # Macros implemented in Python.
 python macro CHAR_CODE(str) = ord(str[1]);
 
 # Accessors for original global properties that ensure they have been loaded.
 const ORIGINAL_REGEXP = (global.RegExp, $RegExp);
 const ORIGINAL_DATE   = (global.Date, $Date);
 
 # Constants used on an array to implement the properties of the RegExp object.
 const REGEXP_NUMBER_OF_CAPTURES = 0;
@@ skipping 16 matching lines @@
 macro MS_FROM_TIME(time) = (Modulo(time, 1000));
 
 # Last input and last subject of regexp matches.
 macro LAST_SUBJECT(array) = ((array)[1]);
 macro LAST_INPUT(array) = ((array)[2]);
 
 # REGEXP_FIRST_CAPTURE
 macro CAPTURE(index) = (3 + (index));
 const CAPTURE0 = 3;
 const CAPTURE1 = 4;