llvmruby.org

LLVMRuby is a pretty straighforward wrapper around the C++ API for generating LLVM bytecode and JIT compilation. The LLVM API is both very well designed and very object oriented and so maps pretty straightforwardly into Ruby. Here is a simple example of using LLVMRuby to construct and JIT compile a function which manipulates native Ruby objects.

require 'llvm'
include LLVM
include RubyInternals

class Builder
  include RubyHelpers
end

m = LLVM::Module.new('ruby_bindings_examples')
ExecutionEngine.get(m)

def ftype(ret_type, arg_types)
  Type.function(ret_type, arg_types)
end

rb_ary_new = m.external_function('rb_ary_new', ftype(VALUE, []))
rb_to_id = m.external_function('rb_to_id', ftype(VALUE, [VALUE]))
rb_ivar_get = m.external_function('rb_ivar_get', ftype(VALUE, [VALUE, ID]))
rb_ivar_set = m.external_function('rb_ivar_set', ftype(VALUE, [VALUE, ID, VALUE]))

class TestClass
  def initialize
    @shaka = 'khan'
  end
end

test_instance = TestClass.new

# take an object and an instance variable symbol, return value of instance variable
type = Type.function(VALUE, [VALUE, VALUE])
f = m.get_or_insert_function('shakula', type)
obj, ivar_sym = f.arguments
b = f.create_block.builder
new_ary = b.call(rb_ary_new)
ivar_id = b.call(rb_to_id, ivar_sym)
ret_val = b.call(rb_ivar_get, obj, ivar_id)
b.return(ret_val)
ret = ExecutionEngine.run_function(f, test_instance, :@shaka)
puts "get instance variable @shaka: #{ret.inspect}"