209 lines
8.0 KiB
Ruby
209 lines
8.0 KiB
Ruby
require_relative "tree"
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require_relative "method_compiler/assignment"
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require_relative "method_compiler/basic_values"
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require_relative "method_compiler/call_site"
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require_relative "method_compiler/collections"
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require_relative "method_compiler/field_access"
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require_relative "method_compiler/if_statement"
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require_relative "method_compiler/name_expression"
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require_relative "method_compiler/operator_expression"
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require_relative "method_compiler/return_statement"
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require_relative "method_compiler/statement_list"
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require_relative "method_compiler/while_statement"
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module Vm
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CompilerModules = [ "assignment" , "basic_values" , "call_site",
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"collections" , "field_access",
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"if_statement" , "name_expression" ,
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"operator_expression" , "return_statement", "statement_list",
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"while_statement"]
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CompilerModules.each do |mod|
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# require_relative "method_compiler/" + mod
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end
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# Compiling is the conversion of the AST into 2 things:
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# - code (ie sequences of Instructions inside Methods)
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# - an object graph containing all the Methods, their classes and Constants
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#
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# Some compile methods just add code, some may add Instructions while
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# others instantiate Class and TypedMethod objects
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#
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# Everything in ruby is an statement, ie returns a value. So the effect of every compile
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# is that a value is put into the ReturnSlot of the current Message.
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# The compile method (so every compile method) returns the value that it deposits.
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#
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# The process uses a visitor pattern (from AST::Processor) to dispatch according to the
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# type the statement. So a s(:if xx) will become an on_if(node) call.
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# This makes the dispatch extensible, ie Expressions may be added by external code,
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# as long as matching compile methods are supplied too.
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#
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# A compiler can also be used to generate code for a method without AST nodes. In the same way
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# compile methods do, ie adding Instructions etc. In this way code may be generated that
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# has no code equivalent.
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#
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# The Compiler also keeps a list of used registers, from which one may take to use and return to
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# when done. The list may be reset.
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#
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# The Compiler also carries method and class instance variables. The method is where code is
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# added to (with add_code). To be more precise, the @current instruction is where code is added
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# to, and that may be changed with set_current
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# All Statements reset the registers and return nil.
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# Expressions use registers and return the register where their value is stored.
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# Helper function to create a new compiler and compie the statement(s)
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# Statement must be and AST::Node as generated by s expressions
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def self.compile_ast( statement )
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compiler = MethodCompiler.new
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code = Vm.ast_to_code statement
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compiler.process code
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end
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class MethodCompiler
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CompilerModules.each do |mod|
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include Vm.const_get( mod.camelize )
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end
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def initialize( method = nil )
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@regs = []
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if method
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@method = method
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@type = method.for_type
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else
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@type = Parfait.object_space.get_type()
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@method = @type.get_method( :main )
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@method = @type.create_method( :main ,{}) unless @method
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end
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@current = @method.instructions
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end
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attr_reader :type , :method
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# Dispatches `code` according to it's class name, for class NameExpression
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# a method named `on_NameExpression` is invoked with one argument, the `code`
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#
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# @param [Vm::Code, nil] code
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def process(code)
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name = code.class.name.split("::").last
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# Invoke a specific handler
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on_handler = :"on_#{name}"
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if respond_to? on_handler
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return send on_handler, code
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else
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raise "No handler on_#{name}(code) #{code.inspect}"
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end
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end
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# {#process}es each code from `codes` and returns an array of
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# results.
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#
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def process_all(codes)
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codes.to_a.map do |code|
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process code
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end
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end
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# create the method, do some checks and set it as the current method to be added to
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# class_name and method_name are pretty clear, args are given as a ruby array
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def create_method( class_name , method_name , args = {})
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raise "create_method #{class_name}.#{class_name.class}" unless class_name.is_a? Symbol
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clazz = Parfait.object_space.get_class_by_name! class_name
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create_method_for( clazz.instance_type , method_name , args)
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end
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# create a method for the given type ( Parfait type object)
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# method_name is a Symbol
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# args a hash that will be converted to a type
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# the created method is set as the current and the given type too
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# return the compiler (for chaining)
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def create_method_for( type , method_name , args )
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@type = type
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raise "create_method #{type.inspect} is not a Type" unless type.is_a? Parfait::Type
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raise "Args must be Hash #{args}" unless args.is_a?(Hash)
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raise "create_method #{method_name}.#{method_name.class}" unless method_name.is_a? Symbol
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@method = type.create_method( method_name , args)
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self
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end
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# add method entry and exit code. Mainly save_return for the enter and
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# message shuffle and FunctionReturn for the return
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# return self for chaining
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def init_method
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source = "_init_method"
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name = "#{method.for_type.name}.#{method.name}"
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@current = @method.set_instructions( Register.label(source, name))
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# add the type of the locals to the existing NamedList instance
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locals_reg = use_reg(:Type , method.locals )
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list_reg = use_reg(:NamedList )
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add_load_constant("#{name} load locals type", method.locals , locals_reg)
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add_slot_to_reg( "#{name} get locals from method" , :message , :locals , list_reg )
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add_reg_to_slot( "#{name} store locals type in locals" , locals_reg , list_reg , 1 )
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enter = @current # this is where method body goes
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add_label( source, "return #{name}")
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#load the return address into pc, affecting return. (other cpus have commands for this, but not arm)
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add_function_return( source , Register.message_reg , Register.resolve_to_index(:message , :return_address) )
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@current = enter
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self
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end
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# set the insertion point (where code is added with add_code)
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def set_current c
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@current = c
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end
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# add an instruction after the current (insertion point)
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# the added instruction will become the new insertion point
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def add_code instruction
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raise instruction.to_s unless instruction.is_a?(Register::Instruction)
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raise instruction.to_s if( instruction.class.name.split("::").first == "Arm")
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@current.insert(instruction) #insert after current
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@current = instruction
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self
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end
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[:label, :reg_to_slot , :slot_to_reg , :load_constant, :function_return ,
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:transfer , :reg_to_slot , :byte_to_reg , :reg_to_byte].each do |method|
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define_method("add_#{method}".to_sym) do |*args|
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add_code Register.send( method , *args )
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end
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end
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# require a (temporary) register. code must give this back with release_reg
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def use_reg( type , value = nil )
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raise "Not type #{type.inspect}" unless type.is_a?(Symbol) or type.is_a?(Parfait::Type)
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if @regs.empty?
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reg = Register.tmp_reg(type , value)
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else
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reg = @regs.last.next_reg_use(type , value)
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end
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@regs << reg
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return reg
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end
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def copy( reg , source )
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copied = use_reg reg.type
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add_code Reister.transfer source , reg , copied
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copied
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end
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# releasing a register (accuired by use_reg) makes it available for use again
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# thus avoiding possibly using too many registers
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def release_reg reg
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last = @regs.pop
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raise "released register in wrong order, expect #{last} but was #{reg}" if reg != last
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end
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# reset the registers to be used. Start at r4 for next usage.
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# Every statement starts with this, meaning each statement may use all registers, but none
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# get saved. Statements have affect on objects.
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def reset_regs
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@regs.clear
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end
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end
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end
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