1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
|
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
<title>API Extensions</title>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<meta name="Author" content="Mike Pall">
<meta name="Copyright" content="Copyright (C) 2005-2009, Mike Pall">
<meta name="Language" content="en">
<link rel="stylesheet" type="text/css" href="bluequad.css" media="screen">
<link rel="stylesheet" type="text/css" href="bluequad-print.css" media="print">
</head>
<body>
<div id="site">
<a href="http://luajit.org"><span>Lua<span id="logo">JIT</span></span></a>
</div>
<div id="head">
<h1>API Extensions</h1>
</div>
<div id="nav">
<ul><li>
<a href="luajit.html">LuaJIT</a>
<ul><li>
<a href="install.html">Installation</a>
</li><li>
<a href="running.html">Running</a>
</li><li>
<a class="current" href="api.html">API Extensions</a>
</li></ul>
</li><li>
<a href="status.html">Status</a>
<ul><li>
<a href="changes.html">Changes</a>
</li></ul>
</li><li>
<a href="faq.html">FAQ</a>
</li><li>
<a href="http://luajit.org/download.html">Download <span class="ext">»</span></a>
</li></ul>
</div>
<div id="main">
<p>
LuaJIT is fully upwards-compatible with Lua 5.1. It supports all
<a href="http://www.lua.org/manual/5.1/manual.html#5"><span class="ext">»</span> standard Lua
library functions</a> and the full set of
<a href="http://www.lua.org/manual/5.1/manual.html#3"><span class="ext">»</span> Lua/C API
functions</a>.
</p>
<p>
LuaJIT is also fully ABI-compatible to Lua 5.1 at the linker/dynamic
loader level. This means you can compile a C module against the
standard Lua headers and load the same shared library from either Lua
or LuaJIT.
</p>
<h2 id="bit"><tt>bit.*</tt> — Bitwise Operations</h2>
<p>
LuaJIT supports all bitwise operations as defined by
<a href="http://bitop.luajit.org"><span class="ext">»</span> Lua BitOp</a>:
</p>
<pre class="code">
bit.tobit bit.tohex bit.bnot bit.band bit.bor bit.bxor
bit.lshift bit.rshift bit.arshift bit.rol bit.ror bit.bswap
</pre>
<p>
This module is a LuaJIT built-in — you don't need to download or
install Lua BitOp. The Lua BitOp site has full documentation for all
<a href="http://bitop.luajit.org/api.html"><span class="ext">»</span> Lua BitOp API functions</a>.
</p>
<p>
Please make sure to <tt>require</tt> the module before using any of
its functions:
</p>
<pre class="code">
local bit = require("bit")
</pre>
<p>
An already installed Lua BitOp module is ignored by LuaJIT.
This way you can use bit operations from both Lua and LuaJIT on a
shared installation.
</p>
<h2 id="jit"><tt>jit.*</tt> — JIT compiler control</h2>
<p>
The functions in this built-in module control the behavior
of the JIT compiler engine.
</p>
<h3 id="jit_onoff"><tt>jit.on()<br>
jit.off()</tt></h3>
<p>
Turns the whole JIT compiler on (default) or off.
</p>
<p>
These functions are typically used with the command line options
<tt>-j on</tt> or <tt>-j off</tt>.
</p>
<h3 id="jit_flush"><tt>jit.flush()</tt></h3>
<p>
Flushes the whole cache of compiled code.
</p>
<h3 id="jit_flush_tr"><tt>jit.flush(tr)</tt></h3>
<p>
Flushes the code for the specified root trace and all of its
side traces from the cache.
</p>
<h3 id="jit_onoff_func"><tt>jit.on(func|true [,true|false])<br>
jit.off(func|true [,true|false])<br>
jit.flush(func|true [,true|false])</tt></h3>
<p>
<tt>jit.on</tt> enables JIT compilation for a Lua function (this is
the default).
</p>
<p>
<tt>jit.off</tt> disables JIT compilation for a Lua function and
flushes any already compiled code from the code cache.
</p>
<p>
<tt>jit.flush</tt> flushes the code, but doesn't affect the
enable/disable status.
</p>
<p>
The current function, i.e. the Lua function calling this library
function, can also be specified by passing <tt>true</tt> as the first
argument.
</p>
<p>
If the second argument is <tt>true</tt>, JIT compilation is also
enabled, disabled or flushed recursively for all subfunctions of a
function. With <tt>false</tt> only the subfunctions are affected.
</p>
<p>
The <tt>jit.on</tt> and <tt>jit.off</tt> functions only set a flag
which is checked when the function is about to be compiled. They do
not trigger immediate compilation.
</p>
<p>
Typical usage is <tt>jit.off(true, true)</tt> in the main chunk
of a module to turn off JIT compilation for the whole module for
debugging purposes.
</p>
<h3 id="jit_version"><tt>jit.version</tt></h3>
<p>
Contains the LuaJIT version string.
</p>
<h3 id="jit_version_num"><tt>jit.version_num</tt></h3>
<p>
Contains the version number of the LuaJIT core. Version xx.yy.zz
is represented by the decimal number xxyyzz.
</p>
<h3 id="jit_arch"><tt>jit.arch</tt></h3>
<p>
Contains the target architecture name (CPU and optional ABI).
</p>
<h2 id="jit_opt"><tt>jit.opt.*</tt> — JIT compiler optimization control</h2>
<p>
This module provides the backend for the <tt>-O</tt> command line
option.
</p>
<p>
You can also use it programmatically, e.g.:
</p>
<pre class="code">
jit.opt.start(2) -- same as -O2
jit.opt.start("-dce")
jit.opt.start("hotloop=10", "hotexit=2")
</pre>
<p>
Unlike in LuaJIT 1.x, the module is built-in and
<b>optimization is turned on by default!</b>
It's no longer necessary to run <tt>require("jit.opt").start()</tt>,
which was one of the ways to enable optimization.
</p>
<h2 id="jit_util"><tt>jit.util.*</tt> — JIT compiler introspection</h2>
<p>
This module holds functions to introspect the bytecode, generated
traces, the IR and the generated machine code. The functionality
provided by this module is still in flux and therefore undocumented.
</p>
<p>
The debug modules <tt>-jbc</tt>, <tt>-jv</tt> and <tt>-jdump</tt> make
extensive use of these functions. Please check out their source code,
if you want to know more.
</p>
<br class="flush">
</div>
<div id="foot">
<hr class="hide">
Copyright © 2005-2009 Mike Pall
<span class="noprint">
·
<a href="contact.html">Contact</a>
</span>
</div>
</body>
</html>
|
