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69 строки
2.2 KiB
HTML
69 строки
2.2 KiB
HTML
<HTML>
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<HEAD>
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<META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1">
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<META NAME="Author" CONTENT="Norris Boyd">
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<META NAME="GENERATOR" CONTENT="Mozilla/4.05 [en] (WinNT; U) [Netscape]">
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<TITLE>Optimization</TITLE>
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</HEAD>
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<BODY BGCOLOR="#FFFFFF">
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<CENTER>
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<H1>
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Optimization</H1></CENTER>
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<H2>
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Optimization settings</H2>
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<P>The currently supported optimization settings are:</P>
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<P><B>-1</B>
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<P><B></B>Interpretive mode is always
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used. The compilation time is minimized at the expense of runtime performance.
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No class files are generated, which may improve memory usage depending on your
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system.
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<p>
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If the optimization package is not available, then optimization acts as if it is always -1.
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</P>
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<P><B>0</B>
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<P><B></B>No optimizations are
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performed. The bytecode compiler runs fastest in this mode, but the generated byte code
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is less efficient.</P>
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<P><B>1-9</B>
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<P>All optimizations are performed. Simple data & type
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flow analysis is performed to determine which JavaScript variables can be
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allocated to Java VM registers, and which variables are used only as Numbers.
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Local common sub-expressions are collapsed (currently this only happens for
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property lookup, but in the future more expressions may be optimized). All local
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variables and parameters are allocated to Java VM registers. Function call
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targets are speculatively pre-cached (based on the name used in the source) so
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that dispatching can be direct, pending runtime confirmation of the actual
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target. Arguments are passed as Object/Number pairs to reduce conversion
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overhead.</P>
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<P>Note:
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<OL>
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<LI>
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Some language features (indirect calls to eval, use
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of the arguments property of function objects) were previously not supported
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in higher optimization levels. These features have been removed from the
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language in ECMA, so higher optimization levels are now conformant.
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<LI>
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Future versions may allocate more aggressive
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optimizations to higher optimization levels. For compatibility with future
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versions, use level 1. For maximal optimization, use level 9, but retest
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your application when upgrading to new versions.</LI>
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</OL>
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<P>
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<HR WIDTH="100%">
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<BR><A HREF="index.html">back to top</A>
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<br>
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</BODY>
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</HTML>
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