Class: SyntaxTree::YARV::VM

Inherits:
Object
  • Object
show all
Extended by:
Forwardable
Defined in:
lib/syntax_tree/yarv/vm.rb

Defined Under Namespace

Classes: BlockFrame, BreakError, ClassFrame, Frame, FrozenCore, Jump, Leave, MethodFrame, NextError, NullEvents, RescueFrame, ReturnError, STDOUTEvents, Stack, ThrownError, TopFrame

Constant Summary collapse

FROZEN_CORE = 
FrozenCore.new.freeze
DLEXT =

Methods for overriding runtime behavior

".#{RbConfig::CONFIG["DLEXT"]}"
SOEXT = 
".#{RbConfig::CONFIG["SOEXT"]}"

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(events = NullEvents.new) ⇒ VM

Returns a new instance of VM.



216
217
218
219
220
 
# File 'lib/syntax_tree/yarv/vm.rb', line 216

def initialize(events = NullEvents.new)
  @events = events
  @stack = Stack.new(events)
  @frame = nil
end

Instance Attribute Details

#events ⇒ Object (readonly)

Returns the value of attribute events.



209
210
211
 
# File 'lib/syntax_tree/yarv/vm.rb', line 209

def events
  @events
end

#frame ⇒ Object (readonly)

Returns the value of attribute frame.



214
215
216
 
# File 'lib/syntax_tree/yarv/vm.rb', line 214

def frame
  @frame
end

#stack ⇒ Object (readonly)

Returns the value of attribute stack.



211
212
213
 
# File 'lib/syntax_tree/yarv/vm.rb', line 211

def stack
  @stack
end

Instance Method Details

#catch(tag, &block) ⇒ Object 



619
620
621
 
# File 'lib/syntax_tree/yarv/vm.rb', line 619

def catch(tag, &block)
  Kernel.catch(tag, &block)
end

#const_base ⇒ Object

Helper methods for instructions



490
491
492
 
# File 'lib/syntax_tree/yarv/vm.rb', line 490

def const_base
  frame.nesting.last
end

#eval(source, binding = TOPLEVEL_BINDING, filename = "(eval)", lineno = 1) ⇒ Object 



606
607
608
609
610
611
612
613
 
# File 'lib/syntax_tree/yarv/vm.rb', line 606

def eval(
  source,
  binding = TOPLEVEL_BINDING,
  filename = "(eval)",
  lineno = 1
)
  Kernel.yarv_eval(source, binding, filename, lineno)
end

#find_catch_entry(frame, type) ⇒ Object 



340
341
342
343
344
345
346
347
348
349
350
 
# File 'lib/syntax_tree/yarv/vm.rb', line 340

def find_catch_entry(frame, type)
  iseq = frame.iseq
  iseq.catch_table.find do |catch_entry|
    next unless catch_entry.is_a?(type)

    begin_pc = iseq.insns.index(catch_entry.begin_label)
    end_pc = iseq.insns.index(catch_entry.end_label)

    (begin_pc...end_pc).cover?(frame.pc)
  end
end

#frame_at(level) ⇒ Object 



494
495
496
497
498
 
# File 'lib/syntax_tree/yarv/vm.rb', line 494

def frame_at(level)
  current = frame
  level.times { current = current.parent }
  current
end

#frame_svar ⇒ Object 



500
501
502
503
504
 
# File 'lib/syntax_tree/yarv/vm.rb', line 500

def frame_svar
  current = frame
  current = current.parent while current.is_a?(BlockFrame)
  current
end

#frame_yield ⇒ Object 



506
507
508
509
510
 
# File 'lib/syntax_tree/yarv/vm.rb', line 506

def frame_yield
  current = frame
  current = current.parent until current.is_a?(MethodFrame)
  current
end

#frozen_core ⇒ Object 



512
513
514
 
# File 'lib/syntax_tree/yarv/vm.rb', line 512

def frozen_core
  FROZEN_CORE
end

#jump(label) ⇒ Object 



516
517
518
 
# File 'lib/syntax_tree/yarv/vm.rb', line 516

def jump(label)
  Jump.new(label)
end

#leave ⇒ Object 



520
521
522
 
# File 'lib/syntax_tree/yarv/vm.rb', line 520

def leave
  Leave.new(pop)
end

#load(filepath) ⇒ Object 



602
603
604
 
# File 'lib/syntax_tree/yarv/vm.rb', line 602

def load(filepath)
  require_internal(filepath, loading: true)
end

#local_get(index, level) ⇒ Object 



524
525
526
 
# File 'lib/syntax_tree/yarv/vm.rb', line 524

def local_get(index, level)
  stack[frame_at(level).stack_index + index]
end

#local_set(index, level, value) ⇒ Object 



528
529
530
 
# File 'lib/syntax_tree/yarv/vm.rb', line 528

def local_set(index, level, value)
  stack[frame_at(level).stack_index + index] = value
end

#require(filepath) ⇒ Object 



594
595
596
 
# File 'lib/syntax_tree/yarv/vm.rb', line 594

def require(filepath)
  require_internal(filepath, loading: false)
end

#require_internal(filepath, loading: false) ⇒ Object 



545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
 
# File 'lib/syntax_tree/yarv/vm.rb', line 545

def require_internal(filepath, loading: false)
  case (extname = File.extname(filepath))
  when ""
    # search for all the extensions
    searching = filepath
    extensions = ["", ".rb", DLEXT, SOEXT]
  when ".rb", DLEXT, SOEXT
    # search only for the given extension name
    searching = File.basename(filepath, extname)
    extensions = [extname]
  else
    # we don't handle these extensions, raise a load error
    raise LoadError, "cannot load such file -- #{filepath}"
  end

  if filepath.start_with?("/")
    # absolute path, search only in the given directory
    directories = [File.dirname(searching)]
    searching = File.basename(searching)
  else
    # relative path, search in the load path
    directories = $LOAD_PATH
  end

  directories.each do |directory|
    extensions.each do |extension|
      absolute_path = File.join(directory, "#{searching}#{extension}")
      next unless File.exist?(absolute_path)

      if !loading && $LOADED_FEATURES.include?(absolute_path)
        return false
      elsif extension == ".rb"
        require_resolved(absolute_path)
        return true
      elsif loading
        return Kernel.send(:yarv_load, filepath)
      else
        return Kernel.send(:yarv_require, filepath)
      end
    end
  end

  if loading
    Kernel.send(:yarv_load, filepath)
  else
    Kernel.send(:yarv_require, filepath)
  end
end

#require_relative(filepath) ⇒ Object 



598
599
600
 
# File 'lib/syntax_tree/yarv/vm.rb', line 598

def require_relative(filepath)
  Kernel.yarv_require_relative(filepath)
end

#require_resolved(filepath) ⇒ Object 



539
540
541
542
543
 
# File 'lib/syntax_tree/yarv/vm.rb', line 539

def require_resolved(filepath)
  $LOADED_FEATURES << filepath
  iseq = RubyVM::InstructionSequence.compile_file(filepath)
  run_top_frame(InstructionSequence.from(iseq.to_a))
end

#run_block_frame(iseq, frame, *args, **kwargs, &block) ⇒ Object 



356
357
358
359
360
 
# File 'lib/syntax_tree/yarv/vm.rb', line 356

def run_block_frame(iseq, frame, *args, **kwargs, &block)
  run_frame(BlockFrame.new(iseq, frame, stack.length)) do
    setup_arguments(iseq, args, kwargs, block)
  end
end

#run_class_frame(iseq, clazz) ⇒ Object 



362
363
364
 
# File 'lib/syntax_tree/yarv/vm.rb', line 362

def run_class_frame(iseq, clazz)
  run_frame(ClassFrame.new(iseq, frame, stack.length, clazz))
end

#run_frame(frame) ⇒ Object

Helper methods for frames



226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
 
# File 'lib/syntax_tree/yarv/vm.rb', line 226

def run_frame(frame)
  # First, set the current frame to the given value.
  previous = @frame
  @frame = frame
  events.publish_frame_change(@frame)

  # Next, set up the local table for the frame. This is actually incorrect
  # as it could use the values already on the stack, but for now we're
  # just doing this for simplicity.
  stack.concat(Array.new(frame.iseq.local_table.size))

  # Yield so that some frame-specific setup can be done.
  start_label = yield if block_given?
  frame.pc = frame.iseq.insns.index(start_label) if start_label

  # Finally we can execute the instructions one at a time. If they return
  # jumps or leaves we will handle those appropriately.
  loop do
    case (insn = frame.iseq.insns[frame.pc])
    when Integer
      frame.line = insn
      frame.pc += 1
    when Symbol
      events.publish_tracepoint(insn)
      frame.pc += 1
    when InstructionSequence::Label
      # skip labels
      frame.pc += 1
    else
      begin
        events.publish_instruction(frame.iseq, insn)
        result = insn.call(self)
      rescue ReturnError => error
        raise if frame.iseq.type != :method

        stack.slice!(frame.stack_index..)
        @frame = frame.parent
        events.publish_frame_change(@frame)

        return error.value
      rescue BreakError => error
        raise if frame.iseq.type != :block

        catch_entry =
          find_catch_entry(frame, InstructionSequence::CatchBreak)
        raise unless catch_entry

        stack.slice!(
          (
            frame.stack_index + frame.iseq.local_table.size +
              catch_entry.restore_sp
          )..
        )
        @frame = frame
        events.publish_frame_change(@frame)

        frame.pc = frame.iseq.insns.index(catch_entry.exit_label)
        push(result = error.value)
      rescue NextError => error
        raise if frame.iseq.type != :block

        catch_entry =
          find_catch_entry(frame, InstructionSequence::CatchNext)
        raise unless catch_entry

        stack.slice!(
          (
            frame.stack_index + frame.iseq.local_table.size +
              catch_entry.restore_sp
          )..
        )
        @frame = frame
        events.publish_frame_change(@frame)

        frame.pc = frame.iseq.insns.index(catch_entry.exit_label)
        push(result = error.value)
      rescue Exception => error
        catch_entry =
          find_catch_entry(frame, InstructionSequence::CatchRescue)
        raise unless catch_entry

        stack.slice!(
          (
            frame.stack_index + frame.iseq.local_table.size +
              catch_entry.restore_sp
          )..
        )
        @frame = frame
        events.publish_frame_change(@frame)

        frame.pc = frame.iseq.insns.index(catch_entry.exit_label)
        push(result = run_rescue_frame(catch_entry.iseq, frame, error))
      end

      case result
      when Jump
        frame.pc = frame.iseq.insns.index(result.label) + 1
      when Leave
        # this shouldn't be necessary, but is because we're not handling
        # the stack correctly at the moment
        stack.slice!(frame.stack_index..)

        # restore the previous frame
        @frame = previous || frame.parent
        events.publish_frame_change(@frame) if @frame

        return result.value
      else
        frame.pc += 1
      end
    end
  end
end

#run_method_frame(name, nesting, iseq, _self, *args, **kwargs, &block) ⇒ Object 



366
367
368
369
370
371
372
373
374
375
376
377
378
 
# File 'lib/syntax_tree/yarv/vm.rb', line 366

def run_method_frame(name, nesting, iseq, _self, *args, **kwargs, &block)
  run_frame(
    MethodFrame.new(
      iseq,
      nesting,
      frame,
      stack.length,
      _self,
      name,
      block
    )
  ) { setup_arguments(iseq, args, kwargs, block) }
end

#run_rescue_frame(iseq, frame, error) ⇒ Object 



380
381
382
383
384
385
 
# File 'lib/syntax_tree/yarv/vm.rb', line 380

def run_rescue_frame(iseq, frame, error)
  run_frame(RescueFrame.new(iseq, frame, stack.length)) do
    local_set(0, 0, error)
    nil
  end
end

#run_top_frame(iseq) ⇒ Object 



352
353
354
 
# File 'lib/syntax_tree/yarv/vm.rb', line 352

def run_top_frame(iseq)
  run_frame(TopFrame.new(iseq))
end

#setup_arguments(iseq, args, kwargs, block) ⇒ Object 



387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
 
# File 'lib/syntax_tree/yarv/vm.rb', line 387

def setup_arguments(iseq, args, kwargs, block)
  locals = [*args]
  local_index = 0
  start_label = nil

  # First, set up all of the leading arguments. These are positional and
  # required arguments at the start of the argument list.
  if (lead_num = iseq.argument_options[:lead_num])
    lead_num.times do
      local_set(local_index, 0, locals.shift)
      local_index += 1
    end
  end

  # Next, set up all of the optional arguments. The opt array contains
  # the labels that the frame should start at if the optional is
  # present. The last element of the array is the label that the frame
  # should start at if all of the optional arguments are present.
  if (opt = iseq.argument_options[:opt])
    opt[0...-1].each do |label|
      if locals.empty?
        start_label = label
        break
      else
        local_set(local_index, 0, locals.shift)
        local_index += 1
      end

      start_label = opt.last if start_label.nil?
    end
  end

  # If there is a splat argument, then we'll set that up here. It will
  # grab up all of the remaining positional arguments.
  if (rest_start = iseq.argument_options[:rest_start])
    if (post_start = iseq.argument_options[:post_start])
      length = post_start - rest_start
      local_set(local_index, 0, locals[0...length])
      locals = locals[length..]
    else
      local_set(local_index, 0, locals.dup)
      locals.clear
    end
    local_index += 1
  end

  # Next, set up any post arguments. These are positional arguments that
  # come after the splat argument.
  if (post_num = iseq.argument_options[:post_num])
    post_num.times do
      local_set(local_index, 0, locals.shift)
      local_index += 1
    end
  end

  if (keyword_option = iseq.argument_options[:keyword])
    # First, set up the keyword bits array.
    keyword_bits =
      keyword_option.map do |config|
        kwargs.key?(config.is_a?(Array) ? config[0] : config)
      end

    iseq.local_table.locals.each_with_index do |local, index|
      # If this is the keyword bits local, then set it appropriately.
      if local.name.is_a?(Integer)
        local_set(index, 0, keyword_bits)
        next
      end

      # First, find the configuration for this local in the keywords
      # list if it exists.
      name = local.name
      config =
        keyword_option.find do |keyword|
          keyword.is_a?(Array) ? keyword[0] == name : keyword == name
        end

      # If the configuration doesn't exist, then the local is not a
      # keyword local.
      next unless config

      if !config.is_a?(Array)
        # required keyword
        local_set(index, 0, kwargs.fetch(name))
      elsif !config[1].nil?
        # optional keyword with embedded default value
        local_set(index, 0, kwargs.fetch(name, config[1]))
      else
        # optional keyword with expression default value
        local_set(index, 0, kwargs[name])
      end
    end
  end

  local_set(local_index, 0, block) if iseq.argument_options[:block_start]

  start_label
end

#throw(tag, value = nil) ⇒ Object 



615
616
617
 
# File 'lib/syntax_tree/yarv/vm.rb', line 615

def throw(tag, value = nil)
  Kernel.throw(tag, value)
end