-The functions in this built-in module control the behavior of the JIT -compiler engine. Note that JIT-compilation is fully automatic — -you probably won't need to use any of the following functions unless -you have special needs. -
- -jit.on()
-jit.off()
--Turns the whole JIT compiler on (default) or off. -
--These functions are typically used with the command line options --j on or -j off. -
- -jit.flush()
--Flushes the whole cache of compiled code. -
- -jit.on(func|true [,true|false])
-jit.off(func|true [,true|false])
-jit.flush(func|true [,true|false])
--jit.on enables JIT compilation for a Lua function (this is -the default). -
--jit.off disables JIT compilation for a Lua function and -flushes any already compiled code from the code cache. -
--jit.flush flushes the code, but doesn't affect the -enable/disable status. -
--The current function, i.e. the Lua function calling this library -function, can also be specified by passing true as the first -argument. -
--If the second argument is true, JIT compilation is also -enabled, disabled or flushed recursively for all sub-functions of a -function. With false only the sub-functions are affected. -
--The jit.on and jit.off functions only set a flag -which is checked when the function is about to be compiled. They do -not trigger immediate compilation. -
--Typical usage is jit.off(true, true) in the main chunk -of a module to turn off JIT compilation for the whole module for -debugging purposes. -
- -jit.flush(tr)
--Flushes the root trace, specified by its number, and all of its side -traces from the cache. The code for the trace will be retained as long -as there are any other traces which link to it. -
- -status, ... = jit.status()
--Returns the current status of the JIT compiler. The first result is -either true or false if the JIT compiler is turned -on or off. The remaining results are strings for CPU-specific features -and enabled optimizations. -
- -jit.version
--Contains the LuaJIT version string. -
- -jit.version_num
--Contains the version number of the LuaJIT core. Version xx.yy.zz -is represented by the decimal number xxyyzz. -
- -jit.os
--Contains the target OS name: -"Windows", "Linux", "OSX", "BSD", "POSIX" or "Other". -
- -jit.arch
--Contains the target architecture name: -"x86", "x64" or "ppcspe". -
- -jit.opt.* — JIT compiler optimization control
--This sub-module provides the backend for the -O command line -option. -
--You can also use it programmatically, e.g.: -
-
-jit.opt.start(2) -- same as -O2
-jit.opt.start("-dce")
-jit.opt.start("hotloop=10", "hotexit=2")
-
--Unlike in LuaJIT 1.x, the module is built-in and -optimization is turned on by default! -It's no longer necessary to run require("jit.opt").start(), -which was one of the ways to enable optimization. -
- -jit.util.* — JIT compiler introspection
--This sub-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. -
--The debug modules -jbc, -jv and -jdump make -extensive use of these functions. Please check out their source code, -if you want to know more. -
--