59 lines
1.4 KiB
Ruby
59 lines
1.4 KiB
Ruby
require_relative "object"
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module Virtual
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# Think flowcharts: blocks are the boxes. The smallest unit of linear code
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# Blocks must end in control instructions (jump/call/return).
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# And the only valid argument for a jump is a Block
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# Blocks form a graph, which is managed by the method
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class Block < Virtual::Object
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def initialize(name , method )
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super()
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@method = method
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@name = name.to_sym
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@branch = nil
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@codes = []
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end
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attr_reader :name , :codes , :method
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attr_accessor :branch
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def reachable ret = []
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add_next ret
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add_branch ret
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ret
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end
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def add_code kode
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@codes << kode
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self
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end
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# returns if this is a block that ends in a call (and thus needs local variable handling)
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def call_block?
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return false unless codes.last.is_a?(CallInstruction)
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return false unless codes.last.opcode == :call
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codes.dup.reverse.find{ |c| c.is_a? StackInstruction }
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end
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private
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# helper for determining reachable blocks
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def add_next ret
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return if @next.nil?
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return if ret.include? @next
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ret << @next
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@next.reachable ret
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end
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# helper for determining reachable blocks
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def add_branch ret
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return if @branch.nil?
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return if ret.include? @branch
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ret << @branch
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@branch.reachable ret
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end
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end
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end |