rubyx/lib/typed/compiler.rb

193 lines
7.1 KiB
Ruby

require_relative "tree"
module Typed
CompilerModules = [ "assignment" , "basic_values" , "call_site",
"class_statement" , "collections" , "field_access",
"function_statement" , "if_statement" , "name_expression" ,
"operator_expression" , "return_statement", "statement_list",
"while_statement"]
CompilerModules.each do |mod|
require_relative "compiler/" + mod
end
# Compiling is the conversion of the AST into 2 things:
# - code (ie sequences of Instructions inside Methods)
# - an object graph containing all the Methods, their classes and Constants
#
# Some compile methods just add code, some may add Instructions while
# others instantiate Class and TypedMethod objects
#
# Everything in ruby is an statement, ie returns a value. So the effect of every compile
# is that a value is put into the ReturnSlot of the current Message.
# The compile method (so every compile method) returns the value that it deposits.
#
# The process uses a visitor pattern (from AST::Processor) to dispatch according to the
# type the statement. So a s(:if xx) will become an on_if(node) call.
# This makes the dispatch extensible, ie Expressions may be added by external code,
# as long as matching compile methods are supplied too.
#
# A compiler can also be used to generate code for a method without AST nodes. In the same way
# compile methods do, ie adding Instructions etc. In this way code may be generated that
# has no code equivalent.
#
# The Compiler also keeps a list of used registers, from which one may take to use and return to
# when done. The list may be reset.
#
# The Compiler also carries method and class instance variables. The method is where code is
# added to (with add_code). To be more precise, the @current instruction is where code is added
# to, and that may be changed with set_current
# All Statements reset the registers and return nil.
# Expressions use registers and return the register where their value is stored.
# Helper function to create a new compiler and compie the statement(s)
def self.compile statement
compiler = Compiler.new
code = Typed.ast_to_code statement
compiler.process code
end
class Compiler
CompilerModules.each do |mod|
include Typed.const_get( mod.camelize )
end
def initialize( method = nil )
@regs = []
if method
@method = method
@type = method.for_type
else
@type = Parfait::Space.object_space.get_type()
@method = @type.get_instance_method( :main )
@method = @type.create_instance_method( :main ,{}) unless @method
end
@current = @method.instructions
end
attr_reader :type , :method
# Dispatches `code` according to it's class name, for class NameExpression
# a method named `on_NameExpression` is invoked with one argument, the `code`
#
# @param [Typed::Code, nil] code
def process(code)
name = code.class.name.split("::").last
# Invoke a specific handler
on_handler = :"on_#{name}"
if respond_to? on_handler
return send on_handler, code
else
raise "No handler on_#{name}(code) #{code.inspect}"
end
end
# {#process}es each code from `codes` and returns an array of
# results.
#
def process_all(codes)
codes.to_a.map do |code|
process code
end
end
# create the method, do some checks and set it as the current method to be added to
# class_name and method_name are pretty clear, args are given as a ruby array
def create_method( class_name , method_name , args = {})
raise "create_method #{class_name}.#{class_name.class}" unless class_name.is_a? Symbol
clazz = Register.machine.space.get_class_by_name! class_name
create_method_for( clazz.instance_type , method_name , args)
end
# create a method for the given type ( Parfait type object)
# method_name is a Symbol
# args a hash that will be converted to a type
# the created method is set as the current and the given type too
# return the compiler (for chaining)
def create_method_for( type , method_name , args )
@type = type
raise "create_method #{type.inspect} is not a Type" unless type.is_a? Parfait::Type
raise "Args must be Hash #{args}" unless args.is_a?(Hash)
raise "create_method #{method_name}.#{method_name.class}" unless method_name.is_a? Symbol
arguments = Parfait::Type.new_for_hash( type.object_class , args )
@method = type.create_instance_method( method_name , arguments)
self
end
# add method entry and exit code. Mainly save_return for the enter and
# message shuffle and FunctionReturn for the return
# return self for chaining
def init_method
source = "_init_method"
name = "#{method.for_type.name}.#{method.name}"
@method.instructions = Register::Label.new(source, name)
@current = enter = method.instructions
add_code Register::Label.new( source, "return #{name}")
#load the return address into pc, affecting return. (other cpus have commands for this, but not arm)
add_code Register::FunctionReturn.new( source , Register.message_reg , Register.resolve_index(:message , :return_address) )
@current = enter
self
end
# set the insertion point (where code is added with add_code)
def set_current c
@current = c
end
# add an instruction after the current (insertion point)
# the added instruction will become the new insertion point
def add_code instruction
unless instruction.is_a?(Register::Instruction)
raise instruction.to_s
end
if( instruction.class.name.split("::").first == "Arm")
raise instruction.to_s
end
@current.insert(instruction) #insert after current
@current = instruction
self
end
# require a (temporary) register. code must give this back with release_reg
def use_reg type , value = nil
raise "Not type #{type.inspect}" unless type.is_a?(Symbol) or type.is_a?(Parfait::Type)
if @regs.empty?
reg = Register.tmp_reg(type , value)
else
reg = @regs.last.next_reg_use(type , value)
end
@regs << reg
return reg
end
def copy reg , source
copied = use_reg reg.type
add_code Reister.transfer source , reg , copied
copied
end
# releasing a register (accuired by use_reg) makes it available for use again
# thus avoiding possibly using too many registers
def release_reg reg
last = @regs.pop
raise "released register in wrong order, expect #{last} but was #{reg}" if reg != last
end
# reset the registers to be used. Start at r4 for next usage.
# Every statement starts with this, meaning each statement may use all registers, but none
# get saved. Statements have affect on objects.
def reset_regs
@regs.clear
end
# ensure the name given is not space and raise exception otherwise
# return the name for chaining
def no_space name
raise "space is a reserved name" if name == :space
name
end
end
end