rubyx/lib/vm/program.rb

110 lines
3.3 KiB
Ruby

require_relative "function"
require_relative "function_call"
require "arm/arm_machine"
module Vm
# A Program represents an executable that we want to build
# it has a list of functions and (global) objects
# The main entry is a function called (of all things) "main", This _must be supplied by the compling
# There is a start and exit block that call main, which receives an array of strings
# While data "ususally" would live in a .data section, we may also "inline" it into the code
# in an oo system all data is represented as objects
# in terms of variables and their visibility, things are simple. They are either local or global
# throwing in a context for unspecified use (well one is to pass the programm/globals around)
class Program < Block
# Initialize with a string for cpu. Naming conventions are: for Machine XXX there exists a module XXX
# with a XXXMachine in it that derives from Vm::Machine
def initialize machine = nil
super("start")
machine = RbConfig::CONFIG["host_cpu"] unless machine
machine = "intel" if machine == "x86_64"
machine = machine.capitalize
Machine.instance = eval("#{machine}::#{machine}Machine").new
@context = Context.new(self)
#global objects (data)
@objects = []
# global functions
@functions = []
@entry = Core::Kernel::main_start
#main gets executed between entry and exit
@main = Block.new("main")
@exit = Core::Kernel::main_exit
end
attr_reader :context , :main , :functions
def add_object o
return if @objects.include? o
@objects << o # TODO check type , no basic values allowed (must be wrapped)
end
def add_function function
raise "not a function #{function}" unless function.is_a? Function
@functions << function
end
def get_function name
name = name.to_sym
@functions.detect{ |f| (f.name == name) }
end
# preferred way of creating new functions (also forward declarations, will flag unresolved later)
def get_or_create_function name
fun = get_function name
unless fun
puts @functions.inspect
fun = Function.new(name)
block = Core::Kernel.send(name)
fun.set_body block
@functions << fun
end
fun
end
# linking entry , main , exit
# functions , objects
def link_at( start , context)
@position = start
@entry.link_at( start , context )
start += @entry.length
@main.link_at( start , context )
start += @main.length
@exit.link_at( start , context)
start += @exit.length
@functions.each do |function|
function.link_at(start , context)
start += function.length
end
@objects.each do |o|
o.link_at(start , context)
start += o.length
end
end
# assemble in the same order as linked
def assemble( io )
link_at( @position , {}) #second link in case of forward declarations
@entry.assemble( io )
@main.assemble( io )
@exit.assemble( io )
@functions.each do |function|
function.assemble(io)
end
@objects.each do |o|
o.assemble(io)
end
io
end
def main= code
@main = code
end
end
end