JIT-Fu

A lesson in the art of JoeJITFu!

JIT-Fu is a PHP extension that exposes an OO API for the creation of native instructions to PHP userland, using libjit.

Disclaimer: the elephpant above is an artists rendition, the actual animal may or may not exist ...

Fibonacci

Because apparently, that's super important ...

<?php
use JITFU\Context;
use JITFU\Type;
use JITFU\Signature;
use JITFU\Func;
use JITFU\Value;

$context = new Context();

$integer   = Type::of(Type::int);

$function = new Func($context, new Signature($integer, [$integer]), function($args) use($integer) {
	$zero     = new Value($this, 0, $integer);
	$one      = new Value($this, 1, $integer);
	$two      = new Value($this, 2, $integer);

	/* if ($arg == 0) return 0; */
	$this->doIf(
		$this->doEq($args[0], $zero),
		function() use ($zero) {
			$this->doReturn($zero);
		}
	);

	/* if ($arg == 1) return 1; */
	$this->doIf(
		$this->doEq($args[0], $one),
		function() use($one) {
			$this->doReturn($one);
		}
	);

	/* return $function($arg-1) + $function($arg-2); */
	$this->doReturn(
		$this->doAdd(
			$this->doCall($this, [$this->doSub($args[0], $one)]),
			$this->doCall($this, [$this->doSub($args[0], $two)])));	
});

if (stripos('win', PHP_OS) !== 0) {
	$function->dump("Fibonacci");
}

var_dump($function(40)); /* __invoke with magicalness */
?>

The code above will yield something like the following output on Linux:

[joe@localhost jit]$ time php -dextension=jitfu.so objects.php 
function Fibonacci(i1 : int) : int
        incoming_reg(i1, rdi)
.L:
        i6 = i1 == 0
        if i1 != 0 then goto .L0
.L:
        return_int(0)
        ends_in_dead
.L0:
        i7 = i1 == 1
        if i1 != 1 then goto .L1
.L:
        return_int(1)
        ends_in_dead
.L1:
        i8 = i1 - 1
        outgoing_reg(i8, rdi)
        call 0x08215dfd0
.L:
        return_reg(i10, rax)
        i12 = i1 - 2
        outgoing_reg(i12, rdi)
        call 0x08215dfd0
.L:
        return_reg(i14, rax)
        i15 = i10 + i14
        return_int(i15)
        ends_in_dead
.L:
.L:
end

int(102334155)


real    0m1.001s
user    0m0.997s
sys     0m0.003s

On my machine, this is ~60 times faster than PHP.

This library is not useful for compiling Zend opcodes

Installation Instructions

Linux

This extension is being developed against the latest libjit sources, it is advisable to install a fresh copy of libjit even if the system has one present:

git clone git://git.sv.gnu.org/libjit.git
cd libjit
./auto_gen.sh
./configure --prefix=/opt
make
sudo make install

Now you can build the PHP extension:

git clone https://github.com/krakjoe/jitfu
cd jitfu
phpize
./configure --with-jitfu=/opt
make
sudo make install

The example sessions above will result in a build of libjit and JIT-Fu

Windows

Snapshots of the master branch are built at 1-2 AM UTC on Mondays. Currently only VC11 x86 builds against PHP 5.5 and 5.6 are available, these should work with the packages that can be downloaded from windows.php.net. The bundled libjit is built as an self-contained binary with MinGW from a patched version of the master branch.

• Download the appropriate package for your PHP installation from here.
• Place php_jitfu.dll in your configured extension_dir.
• Place libjit.dll in a directory that appears in your %PATH%.

Note: The dump() methods are currently unavailable on Windows. Calling these methods on Windows will result in a JITFU\Exception being thrown.

TODO

• integration tests for as much as possible
• other cool things, probably
• pecl & phpdoc