Class: CodeTools::Generator::BasicBlock

Inherits:
Object
  • Object
show all
Defined in:
lib/rubinius/code/compiler/generator.rb

Constant Summary collapse

SEPARATOR_SIZE = 
40

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(generator) ⇒ BasicBlock

Returns a new instance of BasicBlock.



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# File 'lib/rubinius/code/compiler/generator.rb', line 76

def initialize(generator)
  @generator  = generator
  @ip         = generator.ip
  @enter_size = nil
  @max_size   = 0
  @min_size   = 0
  @exit_ip    = 0
  @exit_size  = nil
  @stack      = 0
  @left       = nil
  @right      = nil
  @visited    = false
  @closed     = false
end

Instance Attribute Details

#left ⇒ Object

Returns the value of attribute left.



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# File 'lib/rubinius/code/compiler/generator.rb', line 73

def left
  @left
end

#right ⇒ Object

Returns the value of attribute right.



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# File 'lib/rubinius/code/compiler/generator.rb', line 74

def right
  @right
end

Instance Method Details

#add_stack(read, write) ⇒ Object 



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# File 'lib/rubinius/code/compiler/generator.rb', line 91

def add_stack(read, write)
  read_change = @stack - read
  @min_size = read_change if read_change < @min_size

  @stack += (write - read)

  @max_size = @stack if @stack > @max_size
end

#check_stack(stack_size) ⇒ Object 



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# File 'lib/rubinius/code/compiler/generator.rb', line 226

def check_stack(stack_size)
  if @enter_size
    unless stack_size == @enter_size
      invalid "unbalanced stack at #{location}: #{stack_size} != #{@enter_size}"
    end
  else
    if not @closed
      invalid "control fails to exit properly at #{location}"
    end

    @enter_size = stack_size
  end
end

#close(record_exit = false) ⇒ Object 



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# File 'lib/rubinius/code/compiler/generator.rb', line 104

def close(record_exit=false)
  @closed = true

  if record_exit
    @exit_size = @stack
    @exit_ip = @generator.ip - 1
  end
end

#flow_stack_size(stack) ⇒ Object 



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# File 'lib/rubinius/code/compiler/generator.rb', line 194

def flow_stack_size(stack)
  unless @visited
    @visited = true

    @generator.accumulate_stack(@enter_size + @max_size)

    net_size = @enter_size + @stack

    if net_size < 0
      invalid "net stack underflow in block starting at #{location}"
    end

    if @enter_size + @min_size < 0
      invalid "minimum stack underflow in block starting at #{location}"
    end

    if @exit_size and @enter_size + @exit_size < 1
      invalid "exit stack underflow in block starting at #{location(@exit_ip)}"
    end

    if @left
      @left.check_stack net_size
      stack.push @left unless @left.visited?
    end

    if @right
      @right.check_stack net_size
      stack.push @right unless @right.visited?
    end
  end
end

#invalid(message) ⇒ Object

Raises:



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# File 'lib/rubinius/code/compiler/generator.rb', line 121

def invalid(message)
  puts message
  name = @generator.name.inspect
  size = (SEPARATOR_SIZE - name.size - 2) / 2
  size = 1 if size <= 0
  puts "\n#{"=" * size} #{name} #{"=" * (size + name.size % 2)}"

  literals = @generator.literals
  names = @generator.local_names
  stream = @generator.stream
  i = 0
  n = stream.size
  stack = 0

  while i < n
    insn = Rubinius::InstructionSet[stream[i]]
    printf "[%3d] %04d  %-28s" % [stack, i, insn.opcode.inspect]

    args = stream[i+1, insn.size-1]
    if insn.size > 1
      insn.args.each_with_index do |kind, index|
        arg = args[index]
        case kind
        when :literal
          printf "%s " % literals[arg].inspect
        when :local
          printf "%s " % (names ? names[arg] : arg)
        else
          printf "%d " % arg
        end
      end
    end

    puts

    if insn.variable_stack?
      use = insn.stack_consumed
      if use.kind_of? Array
        use = args[use[1] - 1] + use[0]
      end

      pro = insn.stack_produced
      if pro.kind_of? Array
        pro = (args[pro[1] - 1] * pro[2]) + pro[0]
      end

      stack += pro - use
    else
      stack += insn.stack_difference
    end

    i += insn.size
  end

  puts "-" * SEPARATOR_SIZE

  raise CompileError, message
end

#location(ip = nil) ⇒ Object 



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# File 'lib/rubinius/code/compiler/generator.rb', line 113

def location(ip=nil)
  ip ||= @ip
  line = @generator.ip_to_line(ip)
  "#{@generator.name}: line: #{line}, IP: #{ip}"
end

#open ⇒ Object 



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# File 'lib/rubinius/code/compiler/generator.rb', line 100

def open
  @ip = @generator.ip
end

#validate_stack ⇒ Object 



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# File 'lib/rubinius/code/compiler/generator.rb', line 184

def validate_stack
  @enter_size = 0

  stack = [self]
  until stack.empty?
    bb = stack.shift
    bb.flow_stack_size stack
  end
end

#visited? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/rubinius/code/compiler/generator.rb', line 180

def visited?
  @visited
end