Class: Rubinius::SetTrace

Inherits:
Object
  • Object
show all
Defined in:
lib/set_trace.rb,
app/breakpoint.rb,
app/stepping.rb,
app/frame.rb

Overview

A Rubinius implementation of set_trace_func.

This code is wired into the debugging APIs provided by Rubinius. It tries to isolate the complicated stepping logic as well as simulate Ruby’s set_trace_func.

Defined Under Namespace

Classes: BreakPoint, Frame

Constant Summary collapse

VERSION = 
'0.0.3'
DEFAULT_SET_TRACE_FUNC_OPTS = 
{
  :callback_style => :classic,
  :step_to_parent => :true
}

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ SetTrace

Create a new object. Stepping starts up a thread which is where the callback executes from. Other threads are told that their debugging thread is the stepping thread, and this control of execution is handled.



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# File 'lib/set_trace.rb', line 28

def initialize()
  @file_lines = Hash.new do |hash, path|
    if File.exists? path
      hash[path] = File.readlines(path)
    else
      ab_path = File.join(@root_dir, path)
      if File.exists? ab_path
        hash[path] = File.readlines(ab_path)
      else
        hash[path] = []
      end
    end
  end

  @thread = nil
  @frames = []
  @user_variables = 0
  @breakpoints = []
end

Instance Attribute Details

#breakpoints ⇒ Object (readonly)

Returns the value of attribute breakpoints.



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# File 'lib/set_trace.rb', line 48

def breakpoints
  @breakpoints
end

#current_frame ⇒ Object (readonly)

Returns the value of attribute current_frame.



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# File 'lib/set_trace.rb', line 48

def current_frame
  @current_frame
end

#user_variables ⇒ Object (readonly)

Returns the value of attribute user_variables.



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# File 'lib/set_trace.rb', line 48

def user_variables
  @user_variables
end

#variables ⇒ Object (readonly)

Returns the value of attribute variables.



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# File 'lib/set_trace.rb', line 48

def variables
  @variables
end

#vm_locations ⇒ Object (readonly)

Returns the value of attribute vm_locations.



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# File 'lib/set_trace.rb', line 49

def vm_locations
  @vm_locations
end

Class Method Details

.global(opts = {}) ⇒ Object 



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# File 'lib/set_trace.rb', line 51

def self.global(opts={})
  @global ||= new
end

.set_trace_func(callback_method, opts = {}) ⇒ Object 



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# File 'lib/set_trace.rb', line 55

def self.set_trace_func(callback_method, opts={})
  opts = Rubinius::SetTrace::DEFAULT_SET_TRACE_FUNC_OPTS.merge(opts)
  opts[:call_offset] ||= 1
  global.set_trace_func(callback_method, opts)
end

Instance Method Details

#call_callback ⇒ Object

call callback



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# File 'lib/set_trace.rb', line 133

def call_callback
  case @opts[:callback_style]
  when :classic
    line = @current_frame.line
    file = @current_frame.file
    meth = @current_frame.method
    binding = @current_frame.binding
    id = nil
    classname = nil
    @callback_method.call(@event, file, line, id, binding, classname)
  else
    @callback_method.call(@event, @vm_locations)
  end
  if @tracing
    if @opts[:step_to_parent] 
      @opts[:step_to_parent] = false
      step_to_parent 
    else 
      step_over_by(1)
    end
  end
  listen
end

#decode_one ⇒ Object 



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# File 'lib/set_trace.rb', line 208

def decode_one
  ip = @current_frame.ip

  meth = @current_frame.method
  decoder = Rubinius::InstructionDecoder.new(meth.iseq)
  partial = decoder.decode_between(ip, ip+1)

  partial.each do |ins|
    op = ins.shift

    ins.each_index do |i|
      case op.args[i]
      when :literal
        ins[i] = meth.literals[ins[i]].inspect
      when :local
        if meth.local_names
          ins[i] = meth.local_names[ins[i]]
        end
      end
    end

    display "ip #{ip} = #{op.opcode} #{ins.join(', ')}"
  end
end

#delete_breakpoint(i) ⇒ Object 



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# File 'lib/set_trace.rb', line 161

def delete_breakpoint(i)
  bp = @breakpoints[i-1]

  unless bp
    STDERR.puts "Unknown breakpoint '#{i}'"
    return
  end

  bp.delete!

  @breakpoints[i-1] = nil
end

#frame(num) ⇒ Object 



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# File 'lib/set_trace.rb', line 157

def frame(num)
  @frames[num] ||= Frame.new(self, num, @vm_locations[num])
end

#goto_between(exec, start, fin) ⇒ Object 



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# File 'app/stepping.rb', line 5

def goto_between(exec, start, fin)
  goto = Rubinius::InstructionSet.opcodes_map[:goto]
  git  = Rubinius::InstructionSet.opcodes_map[:goto_if_true]
  gif  = Rubinius::InstructionSet.opcodes_map[:goto_if_false]
  
  iseq = exec.iseq
  
  i = start
  while i < fin
    op = iseq[i]
    case op
    when goto
      return next_interesting(exec, iseq[i + 1]) # goto target
    when git, gif
      return [next_interesting(exec, iseq[i + 1]),
              next_interesting(exec, i + 2)] # target and next ip
    else
      op = Rubinius::InstructionSet[op]
      i += (op.arg_count + 1)
    end
  end
  
  return next_interesting(exec, fin)
end

#listen(step_into = false) ⇒ Object

Stop and wait for a debuggee thread to send us info about stopping at a breakpoint.



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# File 'lib/set_trace.rb', line 97

def listen(step_into=false)
  while true
    if @channel
      if step_into
        @channel << :step
      else
        @channel << true
      end
    end

    # Wait for someone to stop
    @breakpoint, @debugee_thread, @channel, @vm_locations = 
      @local_channel.receive

    # Uncache all frames since we stopped at a new place
    @frames = []

    @current_frame = frame(0)

    if @breakpoint
      @event = @breakpoint.event
      # Only break out if the hit was valid
      break if @breakpoint.hit!(@vm_locations.first)
    else
      @event = 'call'
      break
    end
  end

  # puts
  # puts "Breakpoint: #{@current_frame.describe}"
  # show_code

end

#next_interesting(exec, ip) ⇒ Object 



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# File 'app/stepping.rb', line 30

def next_interesting(exec, ip)
  pop = Rubinius::InstructionSet.opcodes_map[:pop]
  
  if exec.iseq[ip] == pop
    return ip + 1
  end
  
  return ip
end

#send_between(exec, start, fin) ⇒ Object 



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# File 'lib/set_trace.rb', line 174

def send_between(exec, start, fin)
  ss = Rubinius::InstructionSet.opcodes_map[:send_stack]
  sm = Rubinius::InstructionSet.opcodes_map[:send_method]
  sb = Rubinius::InstructionSet.opcodes_map[:send_stack_with_block]

  iseq = exec.iseq

  fin = iseq.size if fin < 0

  i = start
  while i < fin
    op = iseq[i]
    case op
    when ss, sm, sb
      return exec.literals[iseq[i + 1]]
    else
      op = Rubinius::InstructionSet[op]
      i += (op.arg_count + 1)
    end
  end

  return nil
end

#set_breakpoints_between(exec, start_ip, fin_ip) ⇒ Object 



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# File 'app/stepping.rb', line 40

def set_breakpoints_between(exec, start_ip, fin_ip)
  ips = goto_between(exec, start_ip, fin_ip)
  if ips.kind_of? Fixnum
    ip = ips
  else
    one, two = ips
    bp1 = BreakPoint.for_ip(exec, one)
    bp2 = BreakPoint.for_ip(exec, two)
    
    bp1.paired_with(bp2)
    bp2.paired_with(bp1)
    
    bp1.for_step!(current_frame.variables)
    bp2.for_step!(current_frame.variables)
    
    bp1.activate
    bp2.activate
    
    return bp1
  end
  
  if ip == -1
    STDERR.puts "No place to step to"
    return nil
  end
  
  bp = BreakPoint.for_ip(exec, ip)
  bp.for_step!(current_frame.variables)
  bp.activate
  
  return bp
end

#set_trace_func(callback_method, opts = {}) ⇒ Object

Startup the stepping, skipping back opts[:call_offset] frames. This lets you start stepping straight into caller’s method.



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# File 'lib/set_trace.rb', line 65

def set_trace_func(callback_method, opts={})
  if callback_method
    @opts = opts
    call_offset = @opts[:call_offset] || 0
    @callback_method = callback_method
    @tracing  = true
    spinup_thread
    
    # Feed info to the stepping call-back thread!
    @vm_locations = Rubinius::VM.backtrace(call_offset + 1, true)
    
    method = Rubinius::CompiledMethod.of_sender
    
    bp = BreakPoint.new "<start>", method, 0, 0
    channel = Rubinius::Channel.new
    
    @local_channel.send Rubinius::Tuple[bp, Thread.current, channel, 
                                        @vm_locations]
    
    # wait for the callback to release us
    channel.receive
    
    Thread.current.set_debugger_thread @thread
    self
  else
    @tracing = false
  end
end

#show_bytecode(line = @current_frame.line) ⇒ Object 



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# File 'lib/set_trace.rb', line 233

def show_bytecode(line=@current_frame.line)
  meth = @current_frame.method
  start = meth.first_ip_on_line(line)
  fin = meth.first_ip_on_line(line+1)

  if fin == -1
    fin = meth.iseq.size
  end

  puts "Bytecode between #{start} and #{fin-1} for line #{line}"

  decoder = Rubinius::InstructionDecoder.new(meth.iseq)
  partial = decoder.decode_between(start, fin)

  ip = start

  partial.each do |ins|
    op = ins.shift

    ins.each_index do |i|
      case op.args[i]
      when :literal
        ins[i] = meth.literals[ins[i]].inspect
      when :local
        if meth.local_names
          ins[i] = meth.local_names[ins[i]]
        end
      end
    end

    puts " %4d: #{op.opcode} #{ins.join(', ')}" % ip

    ip += (ins.size + 1)
  end
end

#show_code(line = @current_frame.line) ⇒ Object 



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# File 'lib/set_trace.rb', line 198

def show_code(line=@current_frame.line)
  path = @current_frame.method.active_path

  if str = @file_lines[path][line - 1]
    puts "#{line}: #{str}"
  else
    show_bytecode(line)
  end
end

#step_over_by(step) ⇒ Object 



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# File 'app/stepping.rb', line 73

def step_over_by(step)
  f = current_frame
  
  ip = -1
  
  exec = f.method
  possible_line = f.line + step
  fin_ip = exec.first_ip_on_line possible_line, f.ip
  
  if fin_ip == -1
    return step_to_parent
  end
  
  set_breakpoints_between(exec, f.ip, fin_ip)
end

#step_to_parent ⇒ Object 



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# File 'app/stepping.rb', line 89

def step_to_parent
  f = frame(current_frame.number + 1)
  unless f
    STDERR.puts "Unable to find frame to step to next"
    return
  end
  
  exec = f.method
  ip = f.ip
  
  bp = BreakPoint.for_ip(exec, ip, :anon, 'return')
  bp.for_step!(f.variables)
  bp.activate
  
  return bp
end