rubyx/lib/risc/builder.rb
2018-04-16 21:24:27 +03:00

208 lines
7.7 KiB
Ruby

module Risc
# A Builder is used to generate code, either by using it's api, or dsl
#
# The code that is generated can be added to the comiled method, ie to the compiler.
# This is used to generate the builtin methods.
# Or the code can be stored up and returned. This is used in Mom::to_risc methods
class Builder
attr_reader :built , :compiler
# pass a compiler, to which instruction are added (usually)
# second arg determines weather instructions are added (default true)
# call build with a block to build
def initialize(compiler, auto_add)
@compiler = compiler
@auto_add = auto_add
@built = nil
@names = {}
end
# make the magic: convert incoming names into registers that have the
# type set according to the name (using resolve_type)
# anmes are stored, so subsequent calls use the same register
def method_missing(*args)
super if args.length != 1
name = args[0]
return @names[name] if @names.has_key?(name)
if name == :message
reg = Risc.message_reg
reg.builder = self
elsif name.to_s.index("label")
reg = Risc.label( name.to_s , "#{name}_#{object_id}")
else
type = Risc.resolve_type(name , @compiler) #checking
reg = @compiler.use_reg( type.object_class.name )
reg.builder = self
end
@names[name] = reg
reg
end
def if_zero( label )
add_code Risc::IsZero.new("jump if zero" , label)
end
def if_not_zero( label )
add_code Risc::IsNotZero.new("jump if not zero" , label)
end
def branch( label )
add_code Risc::Branch.new("jump to" , label)
end
# build code using dsl (see __init__ or MessageSetup for examples)
# names (that ruby would resolve to a variable/method) are converted
# to registers. << means assignment and [] is supported both on
# L and R values (but only one at a time). R values may also be constants.
# Basically this allows to create LoadConstant, RegToSlot, SlotToReg and
# Transfer instructions with extremely readable code.
# example:
# space << Parfait.object_space # load constant
# message[:receiver] << space #make current message (r0) receiver the space
#
# build result is available as built, but also gets added to compiler, if the
# builder is created with default args
def build(&block)
instance_eval(&block)
@built
end
# adding code to the builder either stores it in the built variable
# or adds it straight to the compiler.
# Depending on wether auto_add was given in construction.
def add_code(ins)
return @compiler.add_code(ins) if @auto_add
if(@built)
@built << ins
else
@built = ins
end
end
# move a machine int from register "from" to a Parfait::Integer in register "to"
# have to grab an integer from space and stick it in the "to" register first.
def add_new_int( source , from, to )
source += "add_new_int "
space = compiler.use_reg(:Space)
int = compiler.use_reg(:Integer)
space_i = Risc.resolve_to_index(:Space, :next_integer)
add_load_constant( source + "space" , Parfait.object_space , space )
add_slot_to_reg( source + "next_i1" , space , space_i , to)
add_slot_to_reg( source + "next_i2" , to , Risc.resolve_to_index(:Integer, :next_integer) , int)
add_reg_to_slot( source + "store link" , int , space , space_i )
add_reg_to_slot( source + "store value" , from , to , Parfait::Integer.integer_index)
end
# load receiver and the first argument (int)
# return both registers
def self_and_int_arg( source )
me = add_known( :receiver )
int_arg = load_int_arg_at(source , 1 )
return me , int_arg
end
# Load the first argument, assumed to be integer
def load_int_arg_at( source , at)
int_arg = compiler.use_reg :Integer
add_slot_to_reg(source , :message , :arguments , int_arg )
add_slot_to_reg(source , int_arg , at + 1, int_arg ) #1 for type
return int_arg
end
# assumed Integer in given register is replaced by the fixnum that it is holding
def reduce_int( source , register )
add_slot_to_reg( source + "int -> fix" , register , Parfait::Integer.integer_index , register)
end
# for computationally building code (ie writing assembler) these short cuts
# help to instantiate risc instructions and add them immediately
[:label, :reg_to_slot , :slot_to_reg , :load_constant, :load_data,
:function_return , :function_call, :op ,
:transfer , :reg_to_slot , :byte_to_reg , :reg_to_byte].each do |method|
define_method("add_#{method}".to_sym) do |*args|
add_code Risc.send( method , *args )
end
end
def add_known(name)
case name
when :receiver
ret = compiler.use_reg compiler.type
add_slot_to_reg(" load self" , :message , :receiver , ret )
return ret
when :space
space = Parfait.object_space
reg = compiler.use_reg :Space , space
add_load_constant( "load space", space , reg )
return reg
when :message
reg = compiler.use_reg :Message
add_transfer( "load message", Risc.message_reg , reg )
return reg
else
raise "Unknow expression #{name}"
end
end
end
# if a symbol is given, it may be the message or the new_message.
# These are mapped to register references.
# The valid symbols (:message,:new_message) are the same that are returned
# by the slots. All data (at any time) is in one of the instance variables of these two
# objects. Risc defines module methods with the same names (and _reg)
def self.resolve_to_register( reference )
return reference if reference.is_a?(RiscValue)
case reference
when :message
return message_reg
when :new_message
return new_message_reg
else
raise "not recognized register reference #{reference} #{reference.class}"
end
end
# The first arg is a class name (possibly lowercase) and the second an instance variable name.
def self.resolve_type( object , compiler )
object = object.type if object.is_a?(RiscValue)
case object
when :name
type = Parfait.object_space.get_class_by_name( :Word ).instance_type
when :frame
type = compiler.method.frame_type
when :message , :next_message , :caller
type = Parfait.object_space.get_class_by_name(:Message).instance_type
when :arguments
type = compiler.method.arguments_type
when :receiver
type = compiler.method.for_type
when Parfait::Object
type = Parfait.object_space.get_class_by_name( object.class.name.split("::").last.to_sym).instance_type
when Symbol
object = object.to_s.camelise.to_sym
clazz = Parfait.object_space.get_class_by_name(object)
raise "Not implemented/found object #{object}:#{object.class}" unless clazz
type = clazz.instance_type
else
raise "Not implemented/found object #{object}:#{object.class}"
end
return type
end
# The first arg is a class name (possibly lowercase) and the second an instance variable name.
# By looking up the class and the type for that class, we can resolve the instance
# variable name to an index.
# The class can be mapped to a register, and so we get a memory address (reg+index)
# Third arg, compiler, is only needed to resolve receiver/arguments/frame
def self.resolve_to_index(object , variable_name ,compiler = nil)
return variable_name if variable_name.is_a?(Integer) or variable_name.is_a?(RiscValue)
type = resolve_type(object , compiler)
index = type.variable_index(variable_name)
raise "Index not found for #{variable_name} in #{object} of type #{type}" unless index
return index
end
end