73 lines
2.6 KiB
Ruby
73 lines
2.6 KiB
Ruby
module Phisol
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class Compiler < AST::Processor
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def initialize()
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@regs = []
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end
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def handler_missing node
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raise "No handler on_#{node.type}(node)"
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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 Blocks) carried by MethodSource
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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 structure (ie Blocks) while
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# others instantiate Class and Method 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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def self.compile statement
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compiler = Compiler.new
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compiler.process statement
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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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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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# 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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require_relative "ast_helper"
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require_relative "compiler/basic_values"
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require_relative "compiler/call_site"
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require_relative "compiler/class_field"
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require_relative "compiler/collections"
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require_relative "compiler/statement_list"
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require_relative "compiler/field_def"
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require_relative "compiler/field_access"
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require_relative "compiler/function_definition"
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require_relative "compiler/if_statement"
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require_relative "compiler/class_statement"
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require_relative "compiler/name_expression"
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require_relative "compiler/operator_value"
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require_relative "compiler/return_statement"
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require_relative "compiler/while_statement"
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