LuaJC

LuaJ, but faster

This is a fork of LuaJ's Lua to Java bytecode compiler. It has been converted to use the ASM framework and many bugs have been fixed.

Changes from the original

• Core debug support (debug.traceback, debug.getinfo and all debug hooks - you cannot get or change locals/upvalues though)
• string.dump support
• getfenv and setfenv support
• Delayed compilation: only compile after n calls.
• Fixes several bugs with generation (see BranchUpvalue2, EdgeCases and NilCallReturn)

Performance

It is tricky to compare the default LuaClosure and LuaJC implementations as several optimisations are applied for debug hooks. These could also be applied to the default VM implementation and increase its performance too.

However there are still some performance increases. Testing on this aes implementation produces these results:

Task	LuaJC	LuaC	Optimised LuaVM
Compilation	0.007993	0.004938	0.004938
Running	9.783356	16.707443	14.739549

Getting started

Firstly add this as a dependency:

repositories {
	maven {
		name = "squiddev"
		url = "https://dl.bintray.com/squiddev/maven"
	}
}

dependencies {
	compile 'org.squiddev:luaj.luajc:1.+'
}

Then install it as a compiler after setting up the globals.

import org.squiddev.luaj.luajc.LuaJC;

public LuaValue load(InputStream stream, String name) throws IOException {
	LuaValue globals = JsePlatform.debugGlobals();
	LuaC.install();
	return LoadState.load(stream, name, globals);
}

You can also pass an instance of the CompileOptions class when installing the compiler.