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RELEASE LuaJIT-2.0.0-beta2

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Mike Pall
2009-12-08 19:49:20 +01:00
parent 55b1695971
commit 1d1fed48a0
46 changed files with 1289 additions and 441 deletions
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147
doc/api.html
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@@ -100,12 +100,6 @@ These functions are typically used with the command line options
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>
@@ -142,6 +136,13 @@ of a module to turn off JIT compilation for the whole module for
debugging purposes.
</p>
<h3 id="jit_flush_tr"><tt>status = jit.flush(tr)</tt></h3>
<p>
Tries to flush the code for the specified trace and all of its
side traces from the cache. Returns <tt>true</tt> on success.
Returns <tt>false</tt> if there are still links to this trace.
</p>
<h3 id="jit_version"><tt>jit.version</tt></h3>
<p>
Contains the LuaJIT version string.
@@ -189,6 +190,140 @@ 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>
<h2 id="c_api">C API extensions</h2>
<p>
LuaJIT adds some extensions to the Lua/C API. The LuaJIT include
directory must be in the compiler search path (<tt>-I<i>path</i></tt>)
to be able to include the required header for C code:
</p>
<pre class="code">
#include "luajit.h"
</pre>
<p>
Or for C++ code:
</p>
<pre class="code">
#include "lua.hpp"
</pre>
<h2 id="luaJIT_setmode"><tt>luaJIT_setmode(L, idx, mode)</tt>
&mdash; Control VM</h2>
<p>
This is a C API extension to allow control of the VM from C code. The
full prototype of <tt>LuaJIT_setmode</tt> is:
</p>
<pre class="code">
LUA_API int luaJIT_setmode(lua_State *L, int idx, int mode);
</pre>
<p>
The returned status is either success (<tt>1</tt>) or failure (<tt>0</tt>).
The second argument is either <tt>0</tt> or a stack index (similar to the
other Lua/C API functions).
</p>
<p>
The third argument specifies the mode, which is 'or'ed with a flag.
The flag can be <tt>LUAJIT_MODE_OFF</tt> to turn a feature on,
<tt>LUAJIT_MODE_ON</tt> to turn a feature off, or
<tt>LUAJIT_MODE_FLUSH</tt> to flush cached code.
</p>
<p>
The following modes are defined:
</p>
<h3 id="mode_engine"><tt>luaJIT_setmode(L, 0, LUAJIT_MODE_ENGINE|flag)</tt></h3>
<p>
Turn the whole JIT compiler on or off or flush the whole cache of compiled code.
</p>
<h3 id="mode_func"><tt>luaJIT_setmode(L, idx, LUAJIT_MODE_FUNC|flag)</tt><br>
<tt>luaJIT_setmode(L, idx, LUAJIT_MODE_ALLFUNC|flag)</tt><br>
<tt>luaJIT_setmode(L, idx, LUAJIT_MODE_ALLSUBFUNC|flag)</tt></h3>
<p>
This sets the mode for the function at the stack index <tt>idx</tt> or
the parent of the calling function (<tt>idx = 0</tt>). It either
enables JIT compilation for a function, disables it and flushes any
already compiled code or only flushes already compiled code. This
applies recursively to all subfunctions of the function with
<tt>LUAJIT_MODE_ALLFUNC</tt> or only to the subfunctions with
<tt>LUAJIT_MODE_ALLSUBFUNC</tt>.
</p>
<h3 id="mode_engine"><tt>luaJIT_setmode(L, trace,<br>
&nbsp;&nbsp;LUAJIT_MODE_TRACE|LUAJIT_MODE_FLUSH)</tt></h3>
<p>
Tries to flush the code for the specified trace and all of its
side traces from the cache.
</p>
<h3 id="mode_engine"><tt>luaJIT_setmode(L, idx, LUAJIT_MODE_WRAPCFUNC|flag)</tt></h3>
<p>
This mode defines a wrapper function for calls to C functions. The
first time this is called with <tt>LUAJIT_MODE_ON</tt>, the stack
index at <tt>idx</tt> must be a <tt>lightuserdata</tt> object holding
a pointer to the wrapper function. All <b>subsequently created C
functions</b> are called through the wrapper functions. After the initial
definition <tt>idx</tt> can be left at <tt>0</tt> when turning the mode
on or off.
</p>
<p>
The wrapper function can be used for debugging purposes or to catch
and convert foreign exceptions. Recommended usage can be seen in this
C++ code excerpt:
</p>
<pre class="code">
#include &lt;exception&gt;
#include "lua.hpp"
// Catch C++ exceptions and convert them to Lua error messages.
// Customize as needed for your own exception classes.
static int wrap_exceptions(lua_State *L, lua_CFunction f)
{
try {
return f(L); // Call wrapped function and return result.
} catch (const char *s) { // Catch and convert exceptions.
lua_pushstring(L, s);
} catch (std::exception& e) {
lua_pushstring(L, e.what());
} catch (...) {
lua_pushliteral(L, "caught (...)");
}
return lua_error(L); // Rethrow as a Lua error.
}
static int myregister(lua_State *L)
{
...
// Define wrapper function and enable it.
lua_pushlightuserdata(L, (void *)wrap_exceptions);
luaJIT_setmode(L, -1, LUAJIT_MODE_WRAPCFUNC|LUAJIT_MODE_ON);
lua_pop(L, 1);
luaL_register(L, "mymodule", myfuncs); // Pass luaL_Reg list.
luaJIT_setmode(L, 0, LUAJIT_MODE_WRAPCFUNC|LUAJIT_MODE_OFF);
...
// Wrap some more C++ functions which might throw an exception.
luaJIT_setmode(L, 0, LUAJIT_MODE_WRAPCFUNC|LUAJIT_MODE_ON);
lua_pushcfunction(L, mythrowingfunc1);
lua_pushcclosure(L, mythrowingfunc2, 1);
luaJIT_setmode(L, 0, LUAJIT_MODE_WRAPCFUNC|LUAJIT_MODE_OFF);
...
}
</pre>
<p>
Note that you can only define <b>a single global wrapper function</b>,
so be careful when using this mechanism from multiple C++ modules.
Also note that this mechanism is not without overhead. It should only
be enabled for definitions of C++ functions that can actually throw
exceptions. If you're embedding LuaJIT into an application, only
enable it <b>after</b> running <tt>luaL_openlibs</tt>.
</p>
<p>
LuaJIT already intercepts exception handling for systems using
ELF/DWARF2 stack unwinding (e.g. Linux). This is a zero-cost mechanism
and always enabled. You don't need to use any wrapper functions,
except when you want to get a more specific error message than
<tt>"C++&nbsp;exception"</tt>.
</p>
<br class="flush">
</div>
<div id="foot">