Class: ElfUtils::Section::DebugLine::LineNumberProgram::StateMachine

Inherits:
Object
  • Object
show all
Includes:
CTypes::Helpers
Defined in:
lib/elf_utils/section/debug_line/line_number_program/state_machine.rb

Defined Under Namespace

Classes: StateRegisters

Constant Summary collapse

StandardOpCodes = 
ElfUtils::Types::Dwarf::StandardOpCodes
ExtendedOpCodes = 
ElfUtils::Types::Dwarf::ExtendedOpCodes
ULEB128 = 
ElfUtils::Types::ULEB128
SLEB128 = 
ElfUtils::Types::SLEB128

Instance Method Summary collapse

Constructor Details

#initialize(program) ⇒ StateMachine

Returns a new instance of StateMachine.



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# File 'lib/elf_utils/section/debug_line/line_number_program/state_machine.rb', line 67

def initialize(program)
  @opcode_base = program.header.opcode_base
  @standard_opcode_lengths = program.standard_opcode_lengths
  @special_opcodes = build_special_opcode_table(program.header)
  @addr_type = program.file.elf_type(:Addr)

  # initial state
  @initial_registers = StateRegisters.new(
    minimum_instruction_length: program.header.minimum_instruction_length,
    maximum_operations_per_instruction: (program.header.version >= 4) ?
        program.header.maximum_operations_per_instruction : 1,
    is_stmt: program.header.default_is_stmt == 1
  ).freeze
end

Instance Method Details

#process(opcodes) ⇒ Object 



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# File 'lib/elf_utils/section/debug_line/line_number_program/state_machine.rb', line 82

def process(opcodes)
  buf = opcodes
  opcode_base = @opcode_base
  matrix = []
  registers = @initial_registers.dup

  # TODO merge unpack & eval steps for extended & special opcodes
  until buf.empty?
    byte = uint8.unpack(buf)
    if byte == 0
      opcode, args, buf = unpack_extended_op(buf[1..])
      eval_extended_opcode(matrix, registers, opcode, args)
    elsif byte < opcode_base
      buf = eval_standard_opcode(buf, matrix, registers)
    else
      opcode, buf = byte, buf[1..]
      opcode = @special_opcodes[opcode]
      eval_special_opcode(matrix, registers, opcode)
    end
  end

  matrix
end