Torsten Rüger
d6c38d15ba
Before, when the type was determined, it was assumed that the method can be resolved. But off course tis is not true, as methods may be defined later in the file. Two solutions for that. One could (and should) define all methods and only then start to compile. Thus having the type safety. Or (as now) make a dynamic call and let it fail at runtime.
105 lines
3.9 KiB
Ruby
105 lines
3.9 KiB
Ruby
module Vool
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# Sending in a dynamic language is off course not as simple as just calling.
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# The function that needs to be called depends after all on the receiver,
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# and no guarantees can be made on what that is.
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#
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# It helps to know that usually (>99%) the class of the receiver does not change.
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# Our stategy then is to cache the functions and only dynamically determine it in
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# case of a miss (the 1%, and first invocation)
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#
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# As cache key we must use the type of the object (which is the first word of _every_ object)
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# as that is constant, and function implementations depend on the type (not class)
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class SendStatement < CallStatement
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attr_reader :block
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def block
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return nil if arguments.empty?
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bl = arguments.last
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bl.is_a?(BlockStatement) ? bl : nil
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end
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def add_block( block )
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@arguments << block
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end
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def each(&block)
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super
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self.block.each(&block) if self.block
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end
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# lazy init this, to keep the dependency (which goes to parfait and booting) at bay
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def dynamic_call
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@dynamic ||= Mom::DynamicCall.new()
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end
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# A Send breaks down to 2 steps:
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# - Setting up the next message, with receiver, arguments, and (importantly) return address
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# - a CachedCall , or a SimpleCall, depending on wether the receiver type can be determined
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def to_mom( compiler )
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puts "Compiling #{self.to_s}"
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@receiver = SelfExpression.new(compiler.receiver_type) if @receiver.is_a?(SelfExpression)
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if(@receiver.ct_type)
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method = @receiver.ct_type.resolve_method(self.name)
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return simple_call(compiler, method) if method
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end
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cached_call(compiler)
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end
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def message_setup(compiler,called_method)
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setup = Mom::MessageSetup.new( called_method )
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mom_receive = @receiver.slot_definition(compiler)
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arg_target = [:message , :next_message , :arguments]
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args = []
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@arguments.each_with_index do |arg , index| # +1 because of type
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args << Mom::SlotLoad.new(self, arg_target + [index + 1] , arg.slot_definition(compiler))
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end
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setup << Mom::ArgumentTransfer.new(self, mom_receive , args )
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end
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def simple_call(compiler, called_method)
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message_setup(compiler,called_method) << Mom::SimpleCall.new(called_method)
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end
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# this breaks cleanly into two parts:
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# - check the cached type and if neccessary update
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# - call the cached method
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def cached_call(compiler)
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cache_check(compiler) << call_cached_method(compiler)
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end
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# check that current type is the cached type
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# if not, change and find method for the type (simple_call to resolve_method)
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# conceptually easy in ruby, but we have to compile that "easy" ruby
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def cache_check(compiler)
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ok = Mom::Label.new(self,"cache_ok_#{self.object_id}")
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check = build_condition(ok, compiler) # if cached_type != current_type
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check << Mom::SlotLoad.new(self,[dynamic_call.cache_entry, :cached_type] , receiver_type_definition(compiler))
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check << Mom::ResolveMethod.new(self, @name , dynamic_call.cache_entry )
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check << ok
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end
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# to call the method (that we know now to be in the cache), we move the method
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# to reg1, do the setup (very similar to static) and call
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def call_cached_method(compiler)
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message_setup(compiler,dynamic_call.cache_entry) << dynamic_call
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end
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def to_s(depth = 0)
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sen = "#{receiver}.#{name}(#{@arguments.collect{|a| a.to_s}.join(', ')})"
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at_depth(depth , sen)
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end
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private
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def receiver_type_definition(compiler)
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defi = @receiver.slot_definition(compiler)
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defi.slots << :type
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defi
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end
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def build_condition(ok_label, compiler)
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cached_type = Mom::SlotDefinition.new(dynamic_call.cache_entry , [:cached_type])
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current_type = receiver_type_definition(compiler)
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Mom::NotSameCheck.new(cached_type , current_type, ok_label)
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end
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end
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end
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