126 lines
4.4 KiB
Ruby
126 lines
4.4 KiB
Ruby
module Risc
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class Builder
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attr_reader :built , :compiler
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# pass a compiler, to which instruction are added (usually)
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# call build or build_and_return with a block
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def initialize(compiler)
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@compiler = compiler
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@names = {}
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end
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# make the magic: convert incoming names into registers that have the
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# type set according to the name (using resolve_type)
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# anmes are stored, so subsequent calls use the same register
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def method_missing(*args)
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super if args.length != 1
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name = args[0]
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return @names[name] if @names.has_key?(name)
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if name == :message
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reg = Risc.message_reg
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else
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type = Risc.resolve_type(name , @compiler) #checking
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reg = @compiler.use_reg( type.object_class.name )
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end
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@names[name] = reg
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reg.builder = self
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reg
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end
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# build code using dsl (see __init__ or MessageSetup for examples)
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# names (that ruby would resolve to a variable/method) are converted
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# to registers. << means assignment and [] is supported both on
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# L and R values (but only one at a time). R values may also be constants.
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# Basically this allows to create LoadConstant, RegToSlot, SlotToReg and
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# Transfer instructions with extremely readable code.
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# example:
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# space << Parfait.object_space # load constant
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# message[:receiver] << space #make current message (r0) receiver the space
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#
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# build result is available as built, but also gets added to compiler
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def build(&block)
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risc = build_and_return(&block)
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@compiler.add_code(risc)
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risc
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end
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# version of build that does not add to compiler, just returns the code
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def build_and_return(&block)
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@built = nil
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instance_eval(&block)
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risc = @built
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@built = nil
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return risc
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end
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def add_instruction(ins)
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if(@built)
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@built << ins
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else
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@built = ins
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end
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end
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end
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# if a symbol is given, it may be the message or the new_message.
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# These are mapped to register references.
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# The valid symbols (:message,:new_message) are the same that are returned
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# by the slots. All data (at any time) is in one of the instance variables of these two
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# objects. Risc defines module methods with the same names (and _reg)
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def self.resolve_to_register( reference )
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return reference if reference.is_a?(RiscValue)
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case reference
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when :message
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return message_reg
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when :new_message
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return new_message_reg
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else
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raise "not recognized register reference #{reference} #{reference.class}"
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end
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end
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# The first arg is a class name (possibly lowercase) and the second an instance variable name.
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def self.resolve_type( object , compiler )
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object = object.type if object.is_a?(RiscValue)
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case object
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when :name
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type = Parfait.object_space.get_class_by_name( :Word ).instance_type
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when :frame
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type = compiler.method.frame_type
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when :message , :next_message , :caller
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type = Parfait.object_space.get_class_by_name(:Message).instance_type
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when :arguments
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type = compiler.method.arguments_type
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when :receiver
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type = compiler.method.for_type
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when Parfait::Object
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type = Parfait.object_space.get_class_by_name( object.class.name.split("::").last.to_sym).instance_type
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when Symbol
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object = object.to_s.camelize.to_sym
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clazz = Parfait.object_space.get_class_by_name(object)
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raise "Not implemented/found object #{object}:#{object.class}" unless clazz
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type = clazz.instance_type
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else
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raise "Not implemented/found object #{object}:#{object.class}"
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end
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return type
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end
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# The first arg is a class name (possibly lowercase) and the second an instance variable name.
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# By looking up the class and the type for that class, we can resolve the instance
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# variable name to an index.
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# The class can be mapped to a register, and so we get a memory address (reg+index)
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# Third arg, compiler, is only needed to resolve receiver/arguments/frame
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def self.resolve_to_index(object , variable_name ,compiler = nil)
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return variable_name if variable_name.is_a?(Integer) or variable_name.is_a?(RiscValue)
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type = resolve_type(object , compiler)
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index = type.variable_index(variable_name)
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raise "Index not found for #{variable_name} in #{object} of type #{type}" unless index
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return index
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end
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end
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