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Issue 1265923002: Debugger: move implementation to a separate folder. (Closed) Base URL: https://chromium.googlesource.com/v8/v8.git@master
Patch Set: rebase Created 5 years, 4 months ago
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1 // Copyright 2012 the V8 project authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5
6 #include "src/v8.h"
7
8 #include "src/liveedit.h"
9
10 #include "src/code-stubs.h"
11 #include "src/compilation-cache.h"
12 #include "src/compiler.h"
13 #include "src/debug.h"
14 #include "src/deoptimizer.h"
15 #include "src/global-handles.h"
16 #include "src/messages.h"
17 #include "src/parser.h"
18 #include "src/scopeinfo.h"
19 #include "src/scopes.h"
20 #include "src/v8memory.h"
21
22 namespace v8 {
23 namespace internal {
24
25 void SetElementSloppy(Handle<JSObject> object,
26 uint32_t index,
27 Handle<Object> value) {
28 // Ignore return value from SetElement. It can only be a failure if there
29 // are element setters causing exceptions and the debugger context has none
30 // of these.
31 Object::SetElement(object->GetIsolate(), object, index, value, SLOPPY)
32 .Assert();
33 }
34
35
36 // A simple implementation of dynamic programming algorithm. It solves
37 // the problem of finding the difference of 2 arrays. It uses a table of results
38 // of subproblems. Each cell contains a number together with 2-bit flag
39 // that helps building the chunk list.
40 class Differencer {
41 public:
42 explicit Differencer(Comparator::Input* input)
43 : input_(input), len1_(input->GetLength1()), len2_(input->GetLength2()) {
44 buffer_ = NewArray<int>(len1_ * len2_);
45 }
46 ~Differencer() {
47 DeleteArray(buffer_);
48 }
49
50 void Initialize() {
51 int array_size = len1_ * len2_;
52 for (int i = 0; i < array_size; i++) {
53 buffer_[i] = kEmptyCellValue;
54 }
55 }
56
57 // Makes sure that result for the full problem is calculated and stored
58 // in the table together with flags showing a path through subproblems.
59 void FillTable() {
60 CompareUpToTail(0, 0);
61 }
62
63 void SaveResult(Comparator::Output* chunk_writer) {
64 ResultWriter writer(chunk_writer);
65
66 int pos1 = 0;
67 int pos2 = 0;
68 while (true) {
69 if (pos1 < len1_) {
70 if (pos2 < len2_) {
71 Direction dir = get_direction(pos1, pos2);
72 switch (dir) {
73 case EQ:
74 writer.eq();
75 pos1++;
76 pos2++;
77 break;
78 case SKIP1:
79 writer.skip1(1);
80 pos1++;
81 break;
82 case SKIP2:
83 case SKIP_ANY:
84 writer.skip2(1);
85 pos2++;
86 break;
87 default:
88 UNREACHABLE();
89 }
90 } else {
91 writer.skip1(len1_ - pos1);
92 break;
93 }
94 } else {
95 if (len2_ != pos2) {
96 writer.skip2(len2_ - pos2);
97 }
98 break;
99 }
100 }
101 writer.close();
102 }
103
104 private:
105 Comparator::Input* input_;
106 int* buffer_;
107 int len1_;
108 int len2_;
109
110 enum Direction {
111 EQ = 0,
112 SKIP1,
113 SKIP2,
114 SKIP_ANY,
115
116 MAX_DIRECTION_FLAG_VALUE = SKIP_ANY
117 };
118
119 // Computes result for a subtask and optionally caches it in the buffer table.
120 // All results values are shifted to make space for flags in the lower bits.
121 int CompareUpToTail(int pos1, int pos2) {
122 if (pos1 < len1_) {
123 if (pos2 < len2_) {
124 int cached_res = get_value4(pos1, pos2);
125 if (cached_res == kEmptyCellValue) {
126 Direction dir;
127 int res;
128 if (input_->Equals(pos1, pos2)) {
129 res = CompareUpToTail(pos1 + 1, pos2 + 1);
130 dir = EQ;
131 } else {
132 int res1 = CompareUpToTail(pos1 + 1, pos2) +
133 (1 << kDirectionSizeBits);
134 int res2 = CompareUpToTail(pos1, pos2 + 1) +
135 (1 << kDirectionSizeBits);
136 if (res1 == res2) {
137 res = res1;
138 dir = SKIP_ANY;
139 } else if (res1 < res2) {
140 res = res1;
141 dir = SKIP1;
142 } else {
143 res = res2;
144 dir = SKIP2;
145 }
146 }
147 set_value4_and_dir(pos1, pos2, res, dir);
148 cached_res = res;
149 }
150 return cached_res;
151 } else {
152 return (len1_ - pos1) << kDirectionSizeBits;
153 }
154 } else {
155 return (len2_ - pos2) << kDirectionSizeBits;
156 }
157 }
158
159 inline int& get_cell(int i1, int i2) {
160 return buffer_[i1 + i2 * len1_];
161 }
162
163 // Each cell keeps a value plus direction. Value is multiplied by 4.
164 void set_value4_and_dir(int i1, int i2, int value4, Direction dir) {
165 DCHECK((value4 & kDirectionMask) == 0);
166 get_cell(i1, i2) = value4 | dir;
167 }
168
169 int get_value4(int i1, int i2) {
170 return get_cell(i1, i2) & (kMaxUInt32 ^ kDirectionMask);
171 }
172 Direction get_direction(int i1, int i2) {
173 return static_cast<Direction>(get_cell(i1, i2) & kDirectionMask);
174 }
175
176 static const int kDirectionSizeBits = 2;
177 static const int kDirectionMask = (1 << kDirectionSizeBits) - 1;
178 static const int kEmptyCellValue = ~0u << kDirectionSizeBits;
179
180 // This method only holds static assert statement (unfortunately you cannot
181 // place one in class scope).
182 void StaticAssertHolder() {
183 STATIC_ASSERT(MAX_DIRECTION_FLAG_VALUE < (1 << kDirectionSizeBits));
184 }
185
186 class ResultWriter {
187 public:
188 explicit ResultWriter(Comparator::Output* chunk_writer)
189 : chunk_writer_(chunk_writer), pos1_(0), pos2_(0),
190 pos1_begin_(-1), pos2_begin_(-1), has_open_chunk_(false) {
191 }
192 void eq() {
193 FlushChunk();
194 pos1_++;
195 pos2_++;
196 }
197 void skip1(int len1) {
198 StartChunk();
199 pos1_ += len1;
200 }
201 void skip2(int len2) {
202 StartChunk();
203 pos2_ += len2;
204 }
205 void close() {
206 FlushChunk();
207 }
208
209 private:
210 Comparator::Output* chunk_writer_;
211 int pos1_;
212 int pos2_;
213 int pos1_begin_;
214 int pos2_begin_;
215 bool has_open_chunk_;
216
217 void StartChunk() {
218 if (!has_open_chunk_) {
219 pos1_begin_ = pos1_;
220 pos2_begin_ = pos2_;
221 has_open_chunk_ = true;
222 }
223 }
224
225 void FlushChunk() {
226 if (has_open_chunk_) {
227 chunk_writer_->AddChunk(pos1_begin_, pos2_begin_,
228 pos1_ - pos1_begin_, pos2_ - pos2_begin_);
229 has_open_chunk_ = false;
230 }
231 }
232 };
233 };
234
235
236 void Comparator::CalculateDifference(Comparator::Input* input,
237 Comparator::Output* result_writer) {
238 Differencer differencer(input);
239 differencer.Initialize();
240 differencer.FillTable();
241 differencer.SaveResult(result_writer);
242 }
243
244
245 static bool CompareSubstrings(Handle<String> s1, int pos1,
246 Handle<String> s2, int pos2, int len) {
247 for (int i = 0; i < len; i++) {
248 if (s1->Get(i + pos1) != s2->Get(i + pos2)) {
249 return false;
250 }
251 }
252 return true;
253 }
254
255
256 // Additional to Input interface. Lets switch Input range to subrange.
257 // More elegant way would be to wrap one Input as another Input object
258 // and translate positions there, but that would cost us additional virtual
259 // call per comparison.
260 class SubrangableInput : public Comparator::Input {
261 public:
262 virtual void SetSubrange1(int offset, int len) = 0;
263 virtual void SetSubrange2(int offset, int len) = 0;
264 };
265
266
267 class SubrangableOutput : public Comparator::Output {
268 public:
269 virtual void SetSubrange1(int offset, int len) = 0;
270 virtual void SetSubrange2(int offset, int len) = 0;
271 };
272
273
274 static int min(int a, int b) {
275 return a < b ? a : b;
276 }
277
278
279 // Finds common prefix and suffix in input. This parts shouldn't take space in
280 // linear programming table. Enable subranging in input and output.
281 static void NarrowDownInput(SubrangableInput* input,
282 SubrangableOutput* output) {
283 const int len1 = input->GetLength1();
284 const int len2 = input->GetLength2();
285
286 int common_prefix_len;
287 int common_suffix_len;
288
289 {
290 common_prefix_len = 0;
291 int prefix_limit = min(len1, len2);
292 while (common_prefix_len < prefix_limit &&
293 input->Equals(common_prefix_len, common_prefix_len)) {
294 common_prefix_len++;
295 }
296
297 common_suffix_len = 0;
298 int suffix_limit = min(len1 - common_prefix_len, len2 - common_prefix_len);
299
300 while (common_suffix_len < suffix_limit &&
301 input->Equals(len1 - common_suffix_len - 1,
302 len2 - common_suffix_len - 1)) {
303 common_suffix_len++;
304 }
305 }
306
307 if (common_prefix_len > 0 || common_suffix_len > 0) {
308 int new_len1 = len1 - common_suffix_len - common_prefix_len;
309 int new_len2 = len2 - common_suffix_len - common_prefix_len;
310
311 input->SetSubrange1(common_prefix_len, new_len1);
312 input->SetSubrange2(common_prefix_len, new_len2);
313
314 output->SetSubrange1(common_prefix_len, new_len1);
315 output->SetSubrange2(common_prefix_len, new_len2);
316 }
317 }
318
319
320 // A helper class that writes chunk numbers into JSArray.
321 // Each chunk is stored as 3 array elements: (pos1_begin, pos1_end, pos2_end).
322 class CompareOutputArrayWriter {
323 public:
324 explicit CompareOutputArrayWriter(Isolate* isolate)
325 : array_(isolate->factory()->NewJSArray(10)), current_size_(0) {}
326
327 Handle<JSArray> GetResult() {
328 return array_;
329 }
330
331 void WriteChunk(int char_pos1, int char_pos2, int char_len1, int char_len2) {
332 Isolate* isolate = array_->GetIsolate();
333 SetElementSloppy(array_,
334 current_size_,
335 Handle<Object>(Smi::FromInt(char_pos1), isolate));
336 SetElementSloppy(array_,
337 current_size_ + 1,
338 Handle<Object>(Smi::FromInt(char_pos1 + char_len1),
339 isolate));
340 SetElementSloppy(array_,
341 current_size_ + 2,
342 Handle<Object>(Smi::FromInt(char_pos2 + char_len2),
343 isolate));
344 current_size_ += 3;
345 }
346
347 private:
348 Handle<JSArray> array_;
349 int current_size_;
350 };
351
352
353 // Represents 2 strings as 2 arrays of tokens.
354 // TODO(LiveEdit): Currently it's actually an array of charactres.
355 // Make array of tokens instead.
356 class TokensCompareInput : public Comparator::Input {
357 public:
358 TokensCompareInput(Handle<String> s1, int offset1, int len1,
359 Handle<String> s2, int offset2, int len2)
360 : s1_(s1), offset1_(offset1), len1_(len1),
361 s2_(s2), offset2_(offset2), len2_(len2) {
362 }
363 virtual int GetLength1() {
364 return len1_;
365 }
366 virtual int GetLength2() {
367 return len2_;
368 }
369 bool Equals(int index1, int index2) {
370 return s1_->Get(offset1_ + index1) == s2_->Get(offset2_ + index2);
371 }
372
373 private:
374 Handle<String> s1_;
375 int offset1_;
376 int len1_;
377 Handle<String> s2_;
378 int offset2_;
379 int len2_;
380 };
381
382
383 // Stores compare result in JSArray. Converts substring positions
384 // to absolute positions.
385 class TokensCompareOutput : public Comparator::Output {
386 public:
387 TokensCompareOutput(CompareOutputArrayWriter* array_writer,
388 int offset1, int offset2)
389 : array_writer_(array_writer), offset1_(offset1), offset2_(offset2) {
390 }
391
392 void AddChunk(int pos1, int pos2, int len1, int len2) {
393 array_writer_->WriteChunk(pos1 + offset1_, pos2 + offset2_, len1, len2);
394 }
395
396 private:
397 CompareOutputArrayWriter* array_writer_;
398 int offset1_;
399 int offset2_;
400 };
401
402
403 // Wraps raw n-elements line_ends array as a list of n+1 lines. The last line
404 // never has terminating new line character.
405 class LineEndsWrapper {
406 public:
407 explicit LineEndsWrapper(Handle<String> string)
408 : ends_array_(String::CalculateLineEnds(string, false)),
409 string_len_(string->length()) {
410 }
411 int length() {
412 return ends_array_->length() + 1;
413 }
414 // Returns start for any line including start of the imaginary line after
415 // the last line.
416 int GetLineStart(int index) {
417 if (index == 0) {
418 return 0;
419 } else {
420 return GetLineEnd(index - 1);
421 }
422 }
423 int GetLineEnd(int index) {
424 if (index == ends_array_->length()) {
425 // End of the last line is always an end of the whole string.
426 // If the string ends with a new line character, the last line is an
427 // empty string after this character.
428 return string_len_;
429 } else {
430 return GetPosAfterNewLine(index);
431 }
432 }
433
434 private:
435 Handle<FixedArray> ends_array_;
436 int string_len_;
437
438 int GetPosAfterNewLine(int index) {
439 return Smi::cast(ends_array_->get(index))->value() + 1;
440 }
441 };
442
443
444 // Represents 2 strings as 2 arrays of lines.
445 class LineArrayCompareInput : public SubrangableInput {
446 public:
447 LineArrayCompareInput(Handle<String> s1, Handle<String> s2,
448 LineEndsWrapper line_ends1, LineEndsWrapper line_ends2)
449 : s1_(s1), s2_(s2), line_ends1_(line_ends1),
450 line_ends2_(line_ends2),
451 subrange_offset1_(0), subrange_offset2_(0),
452 subrange_len1_(line_ends1_.length()),
453 subrange_len2_(line_ends2_.length()) {
454 }
455 int GetLength1() {
456 return subrange_len1_;
457 }
458 int GetLength2() {
459 return subrange_len2_;
460 }
461 bool Equals(int index1, int index2) {
462 index1 += subrange_offset1_;
463 index2 += subrange_offset2_;
464
465 int line_start1 = line_ends1_.GetLineStart(index1);
466 int line_start2 = line_ends2_.GetLineStart(index2);
467 int line_end1 = line_ends1_.GetLineEnd(index1);
468 int line_end2 = line_ends2_.GetLineEnd(index2);
469 int len1 = line_end1 - line_start1;
470 int len2 = line_end2 - line_start2;
471 if (len1 != len2) {
472 return false;
473 }
474 return CompareSubstrings(s1_, line_start1, s2_, line_start2,
475 len1);
476 }
477 void SetSubrange1(int offset, int len) {
478 subrange_offset1_ = offset;
479 subrange_len1_ = len;
480 }
481 void SetSubrange2(int offset, int len) {
482 subrange_offset2_ = offset;
483 subrange_len2_ = len;
484 }
485
486 private:
487 Handle<String> s1_;
488 Handle<String> s2_;
489 LineEndsWrapper line_ends1_;
490 LineEndsWrapper line_ends2_;
491 int subrange_offset1_;
492 int subrange_offset2_;
493 int subrange_len1_;
494 int subrange_len2_;
495 };
496
497
498 // Stores compare result in JSArray. For each chunk tries to conduct
499 // a fine-grained nested diff token-wise.
500 class TokenizingLineArrayCompareOutput : public SubrangableOutput {
501 public:
502 TokenizingLineArrayCompareOutput(LineEndsWrapper line_ends1,
503 LineEndsWrapper line_ends2,
504 Handle<String> s1, Handle<String> s2)
505 : array_writer_(s1->GetIsolate()),
506 line_ends1_(line_ends1), line_ends2_(line_ends2), s1_(s1), s2_(s2),
507 subrange_offset1_(0), subrange_offset2_(0) {
508 }
509
510 void AddChunk(int line_pos1, int line_pos2, int line_len1, int line_len2) {
511 line_pos1 += subrange_offset1_;
512 line_pos2 += subrange_offset2_;
513
514 int char_pos1 = line_ends1_.GetLineStart(line_pos1);
515 int char_pos2 = line_ends2_.GetLineStart(line_pos2);
516 int char_len1 = line_ends1_.GetLineStart(line_pos1 + line_len1) - char_pos1;
517 int char_len2 = line_ends2_.GetLineStart(line_pos2 + line_len2) - char_pos2;
518
519 if (char_len1 < CHUNK_LEN_LIMIT && char_len2 < CHUNK_LEN_LIMIT) {
520 // Chunk is small enough to conduct a nested token-level diff.
521 HandleScope subTaskScope(s1_->GetIsolate());
522
523 TokensCompareInput tokens_input(s1_, char_pos1, char_len1,
524 s2_, char_pos2, char_len2);
525 TokensCompareOutput tokens_output(&array_writer_, char_pos1,
526 char_pos2);
527
528 Comparator::CalculateDifference(&tokens_input, &tokens_output);
529 } else {
530 array_writer_.WriteChunk(char_pos1, char_pos2, char_len1, char_len2);
531 }
532 }
533 void SetSubrange1(int offset, int len) {
534 subrange_offset1_ = offset;
535 }
536 void SetSubrange2(int offset, int len) {
537 subrange_offset2_ = offset;
538 }
539
540 Handle<JSArray> GetResult() {
541 return array_writer_.GetResult();
542 }
543
544 private:
545 static const int CHUNK_LEN_LIMIT = 800;
546
547 CompareOutputArrayWriter array_writer_;
548 LineEndsWrapper line_ends1_;
549 LineEndsWrapper line_ends2_;
550 Handle<String> s1_;
551 Handle<String> s2_;
552 int subrange_offset1_;
553 int subrange_offset2_;
554 };
555
556
557 Handle<JSArray> LiveEdit::CompareStrings(Handle<String> s1,
558 Handle<String> s2) {
559 s1 = String::Flatten(s1);
560 s2 = String::Flatten(s2);
561
562 LineEndsWrapper line_ends1(s1);
563 LineEndsWrapper line_ends2(s2);
564
565 LineArrayCompareInput input(s1, s2, line_ends1, line_ends2);
566 TokenizingLineArrayCompareOutput output(line_ends1, line_ends2, s1, s2);
567
568 NarrowDownInput(&input, &output);
569
570 Comparator::CalculateDifference(&input, &output);
571
572 return output.GetResult();
573 }
574
575
576 // Unwraps JSValue object, returning its field "value"
577 static Handle<Object> UnwrapJSValue(Handle<JSValue> jsValue) {
578 return Handle<Object>(jsValue->value(), jsValue->GetIsolate());
579 }
580
581
582 // Wraps any object into a OpaqueReference, that will hide the object
583 // from JavaScript.
584 static Handle<JSValue> WrapInJSValue(Handle<HeapObject> object) {
585 Isolate* isolate = object->GetIsolate();
586 Handle<JSFunction> constructor = isolate->opaque_reference_function();
587 Handle<JSValue> result =
588 Handle<JSValue>::cast(isolate->factory()->NewJSObject(constructor));
589 result->set_value(*object);
590 return result;
591 }
592
593
594 static Handle<SharedFunctionInfo> UnwrapSharedFunctionInfoFromJSValue(
595 Handle<JSValue> jsValue) {
596 Object* shared = jsValue->value();
597 CHECK(shared->IsSharedFunctionInfo());
598 return Handle<SharedFunctionInfo>(SharedFunctionInfo::cast(shared));
599 }
600
601
602 static int GetArrayLength(Handle<JSArray> array) {
603 Object* length = array->length();
604 CHECK(length->IsSmi());
605 return Smi::cast(length)->value();
606 }
607
608
609 void FunctionInfoWrapper::SetInitialProperties(Handle<String> name,
610 int start_position,
611 int end_position, int param_num,
612 int literal_count,
613 int parent_index) {
614 HandleScope scope(isolate());
615 this->SetField(kFunctionNameOffset_, name);
616 this->SetSmiValueField(kStartPositionOffset_, start_position);
617 this->SetSmiValueField(kEndPositionOffset_, end_position);
618 this->SetSmiValueField(kParamNumOffset_, param_num);
619 this->SetSmiValueField(kLiteralNumOffset_, literal_count);
620 this->SetSmiValueField(kParentIndexOffset_, parent_index);
621 }
622
623
624 void FunctionInfoWrapper::SetFunctionCode(Handle<Code> function_code,
625 Handle<HeapObject> code_scope_info) {
626 Handle<JSValue> code_wrapper = WrapInJSValue(function_code);
627 this->SetField(kCodeOffset_, code_wrapper);
628
629 Handle<JSValue> scope_wrapper = WrapInJSValue(code_scope_info);
630 this->SetField(kCodeScopeInfoOffset_, scope_wrapper);
631 }
632
633
634 void FunctionInfoWrapper::SetSharedFunctionInfo(
635 Handle<SharedFunctionInfo> info) {
636 Handle<JSValue> info_holder = WrapInJSValue(info);
637 this->SetField(kSharedFunctionInfoOffset_, info_holder);
638 }
639
640
641 Handle<Code> FunctionInfoWrapper::GetFunctionCode() {
642 Handle<Object> element = this->GetField(kCodeOffset_);
643 Handle<JSValue> value_wrapper = Handle<JSValue>::cast(element);
644 Handle<Object> raw_result = UnwrapJSValue(value_wrapper);
645 CHECK(raw_result->IsCode());
646 return Handle<Code>::cast(raw_result);
647 }
648
649
650 MaybeHandle<TypeFeedbackVector> FunctionInfoWrapper::GetFeedbackVector() {
651 Handle<Object> element = this->GetField(kSharedFunctionInfoOffset_);
652 if (element->IsJSValue()) {
653 Handle<JSValue> value_wrapper = Handle<JSValue>::cast(element);
654 Handle<Object> raw_result = UnwrapJSValue(value_wrapper);
655 Handle<SharedFunctionInfo> shared =
656 Handle<SharedFunctionInfo>::cast(raw_result);
657 return Handle<TypeFeedbackVector>(shared->feedback_vector(), isolate());
658 } else {
659 // Scripts may never have a SharedFunctionInfo created.
660 return MaybeHandle<TypeFeedbackVector>();
661 }
662 }
663
664
665 Handle<Object> FunctionInfoWrapper::GetCodeScopeInfo() {
666 Handle<Object> element = this->GetField(kCodeScopeInfoOffset_);
667 return UnwrapJSValue(Handle<JSValue>::cast(element));
668 }
669
670
671 void SharedInfoWrapper::SetProperties(Handle<String> name,
672 int start_position,
673 int end_position,
674 Handle<SharedFunctionInfo> info) {
675 HandleScope scope(isolate());
676 this->SetField(kFunctionNameOffset_, name);
677 Handle<JSValue> info_holder = WrapInJSValue(info);
678 this->SetField(kSharedInfoOffset_, info_holder);
679 this->SetSmiValueField(kStartPositionOffset_, start_position);
680 this->SetSmiValueField(kEndPositionOffset_, end_position);
681 }
682
683
684 Handle<SharedFunctionInfo> SharedInfoWrapper::GetInfo() {
685 Handle<Object> element = this->GetField(kSharedInfoOffset_);
686 Handle<JSValue> value_wrapper = Handle<JSValue>::cast(element);
687 return UnwrapSharedFunctionInfoFromJSValue(value_wrapper);
688 }
689
690
691 class FunctionInfoListener {
692 public:
693 explicit FunctionInfoListener(Isolate* isolate) {
694 current_parent_index_ = -1;
695 len_ = 0;
696 result_ = isolate->factory()->NewJSArray(10);
697 }
698
699 void FunctionStarted(FunctionLiteral* fun) {
700 HandleScope scope(isolate());
701 FunctionInfoWrapper info = FunctionInfoWrapper::Create(isolate());
702 info.SetInitialProperties(fun->name(), fun->start_position(),
703 fun->end_position(), fun->parameter_count(),
704 fun->materialized_literal_count(),
705 current_parent_index_);
706 current_parent_index_ = len_;
707 SetElementSloppy(result_, len_, info.GetJSArray());
708 len_++;
709 }
710
711 void FunctionDone() {
712 HandleScope scope(isolate());
713 FunctionInfoWrapper info =
714 FunctionInfoWrapper::cast(
715 *Object::GetElement(
716 isolate(), result_, current_parent_index_).ToHandleChecked());
717 current_parent_index_ = info.GetParentIndex();
718 }
719
720 // Saves only function code, because for a script function we
721 // may never create a SharedFunctionInfo object.
722 void FunctionCode(Handle<Code> function_code) {
723 FunctionInfoWrapper info =
724 FunctionInfoWrapper::cast(
725 *Object::GetElement(
726 isolate(), result_, current_parent_index_).ToHandleChecked());
727 info.SetFunctionCode(function_code,
728 Handle<HeapObject>(isolate()->heap()->null_value()));
729 }
730
731 // Saves full information about a function: its code, its scope info
732 // and a SharedFunctionInfo object.
733 void FunctionInfo(Handle<SharedFunctionInfo> shared, Scope* scope,
734 Zone* zone) {
735 if (!shared->IsSharedFunctionInfo()) {
736 return;
737 }
738 FunctionInfoWrapper info =
739 FunctionInfoWrapper::cast(
740 *Object::GetElement(
741 isolate(), result_, current_parent_index_).ToHandleChecked());
742 info.SetFunctionCode(Handle<Code>(shared->code()),
743 Handle<HeapObject>(shared->scope_info()));
744 info.SetSharedFunctionInfo(shared);
745
746 Handle<Object> scope_info_list = SerializeFunctionScope(scope, zone);
747 info.SetFunctionScopeInfo(scope_info_list);
748 }
749
750 Handle<JSArray> GetResult() { return result_; }
751
752 private:
753 Isolate* isolate() const { return result_->GetIsolate(); }
754
755 Handle<Object> SerializeFunctionScope(Scope* scope, Zone* zone) {
756 Handle<JSArray> scope_info_list = isolate()->factory()->NewJSArray(10);
757 int scope_info_length = 0;
758
759 // Saves some description of scope. It stores name and indexes of
760 // variables in the whole scope chain. Null-named slots delimit
761 // scopes of this chain.
762 Scope* current_scope = scope;
763 while (current_scope != NULL) {
764 HandleScope handle_scope(isolate());
765 ZoneList<Variable*> stack_list(current_scope->StackLocalCount(), zone);
766 ZoneList<Variable*> context_list(
767 current_scope->ContextLocalCount(), zone);
768 ZoneList<Variable*> globals_list(current_scope->ContextGlobalCount(),
769 zone);
770 current_scope->CollectStackAndContextLocals(&stack_list, &context_list,
771 &globals_list);
772 context_list.Sort(&Variable::CompareIndex);
773
774 for (int i = 0; i < context_list.length(); i++) {
775 SetElementSloppy(scope_info_list,
776 scope_info_length,
777 context_list[i]->name());
778 scope_info_length++;
779 SetElementSloppy(
780 scope_info_list,
781 scope_info_length,
782 Handle<Smi>(Smi::FromInt(context_list[i]->index()), isolate()));
783 scope_info_length++;
784 }
785 SetElementSloppy(scope_info_list,
786 scope_info_length,
787 Handle<Object>(isolate()->heap()->null_value(),
788 isolate()));
789 scope_info_length++;
790
791 current_scope = current_scope->outer_scope();
792 }
793
794 return scope_info_list;
795 }
796
797 Handle<JSArray> result_;
798 int len_;
799 int current_parent_index_;
800 };
801
802
803 void LiveEdit::InitializeThreadLocal(Debug* debug) {
804 debug->thread_local_.frame_drop_mode_ = LiveEdit::FRAMES_UNTOUCHED;
805 }
806
807
808 bool LiveEdit::SetAfterBreakTarget(Debug* debug) {
809 Code* code = NULL;
810 Isolate* isolate = debug->isolate_;
811 switch (debug->thread_local_.frame_drop_mode_) {
812 case FRAMES_UNTOUCHED:
813 return false;
814 case FRAME_DROPPED_IN_IC_CALL:
815 // We must have been calling IC stub. Do not go there anymore.
816 code = isolate->builtins()->builtin(Builtins::kPlainReturn_LiveEdit);
817 break;
818 case FRAME_DROPPED_IN_DEBUG_SLOT_CALL:
819 // Debug break slot stub does not return normally, instead it manually
820 // cleans the stack and jumps. We should patch the jump address.
821 code = isolate->builtins()->builtin(Builtins::kFrameDropper_LiveEdit);
822 break;
823 case FRAME_DROPPED_IN_DIRECT_CALL:
824 // Nothing to do, after_break_target is not used here.
825 return true;
826 case FRAME_DROPPED_IN_RETURN_CALL:
827 code = isolate->builtins()->builtin(Builtins::kFrameDropper_LiveEdit);
828 break;
829 case CURRENTLY_SET_MODE:
830 UNREACHABLE();
831 break;
832 }
833 debug->after_break_target_ = code->entry();
834 return true;
835 }
836
837
838 MaybeHandle<JSArray> LiveEdit::GatherCompileInfo(Handle<Script> script,
839 Handle<String> source) {
840 Isolate* isolate = script->GetIsolate();
841
842 FunctionInfoListener listener(isolate);
843 Handle<Object> original_source =
844 Handle<Object>(script->source(), isolate);
845 script->set_source(*source);
846 isolate->set_active_function_info_listener(&listener);
847
848 {
849 // Creating verbose TryCatch from public API is currently the only way to
850 // force code save location. We do not use this the object directly.
851 v8::TryCatch try_catch(reinterpret_cast<v8::Isolate*>(isolate));
852 try_catch.SetVerbose(true);
853
854 // A logical 'try' section.
855 Compiler::CompileForLiveEdit(script);
856 }
857
858 // A logical 'catch' section.
859 Handle<JSObject> rethrow_exception;
860 if (isolate->has_pending_exception()) {
861 Handle<Object> exception(isolate->pending_exception(), isolate);
862 MessageLocation message_location = isolate->GetMessageLocation();
863
864 isolate->clear_pending_message();
865 isolate->clear_pending_exception();
866
867 // If possible, copy positions from message object to exception object.
868 if (exception->IsJSObject() && !message_location.script().is_null()) {
869 rethrow_exception = Handle<JSObject>::cast(exception);
870
871 Factory* factory = isolate->factory();
872 Handle<String> start_pos_key = factory->InternalizeOneByteString(
873 STATIC_CHAR_VECTOR("startPosition"));
874 Handle<String> end_pos_key =
875 factory->InternalizeOneByteString(STATIC_CHAR_VECTOR("endPosition"));
876 Handle<String> script_obj_key =
877 factory->InternalizeOneByteString(STATIC_CHAR_VECTOR("scriptObject"));
878 Handle<Smi> start_pos(
879 Smi::FromInt(message_location.start_pos()), isolate);
880 Handle<Smi> end_pos(Smi::FromInt(message_location.end_pos()), isolate);
881 Handle<JSObject> script_obj =
882 Script::GetWrapper(message_location.script());
883 Object::SetProperty(rethrow_exception, start_pos_key, start_pos, SLOPPY)
884 .Assert();
885 Object::SetProperty(rethrow_exception, end_pos_key, end_pos, SLOPPY)
886 .Assert();
887 Object::SetProperty(rethrow_exception, script_obj_key, script_obj, SLOPPY)
888 .Assert();
889 }
890 }
891
892 // A logical 'finally' section.
893 isolate->set_active_function_info_listener(NULL);
894 script->set_source(*original_source);
895
896 if (rethrow_exception.is_null()) {
897 return listener.GetResult();
898 } else {
899 return isolate->Throw<JSArray>(rethrow_exception);
900 }
901 }
902
903
904 void LiveEdit::WrapSharedFunctionInfos(Handle<JSArray> array) {
905 Isolate* isolate = array->GetIsolate();
906 HandleScope scope(isolate);
907 int len = GetArrayLength(array);
908 for (int i = 0; i < len; i++) {
909 Handle<SharedFunctionInfo> info(
910 SharedFunctionInfo::cast(
911 *Object::GetElement(isolate, array, i).ToHandleChecked()));
912 SharedInfoWrapper info_wrapper = SharedInfoWrapper::Create(isolate);
913 Handle<String> name_handle(String::cast(info->name()));
914 info_wrapper.SetProperties(name_handle, info->start_position(),
915 info->end_position(), info);
916 SetElementSloppy(array, i, info_wrapper.GetJSArray());
917 }
918 }
919
920
921 // Visitor that finds all references to a particular code object,
922 // including "CODE_TARGET" references in other code objects and replaces
923 // them on the fly.
924 class ReplacingVisitor : public ObjectVisitor {
925 public:
926 explicit ReplacingVisitor(Code* original, Code* substitution)
927 : original_(original), substitution_(substitution) {
928 }
929
930 virtual void VisitPointers(Object** start, Object** end) {
931 for (Object** p = start; p < end; p++) {
932 if (*p == original_) {
933 *p = substitution_;
934 }
935 }
936 }
937
938 virtual void VisitCodeEntry(Address entry) {
939 if (Code::GetObjectFromEntryAddress(entry) == original_) {
940 Address substitution_entry = substitution_->instruction_start();
941 Memory::Address_at(entry) = substitution_entry;
942 }
943 }
944
945 virtual void VisitCodeTarget(RelocInfo* rinfo) {
946 if (RelocInfo::IsCodeTarget(rinfo->rmode()) &&
947 Code::GetCodeFromTargetAddress(rinfo->target_address()) == original_) {
948 Address substitution_entry = substitution_->instruction_start();
949 rinfo->set_target_address(substitution_entry);
950 }
951 }
952
953 virtual void VisitDebugTarget(RelocInfo* rinfo) {
954 VisitCodeTarget(rinfo);
955 }
956
957 private:
958 Code* original_;
959 Code* substitution_;
960 };
961
962
963 // Finds all references to original and replaces them with substitution.
964 static void ReplaceCodeObject(Handle<Code> original,
965 Handle<Code> substitution) {
966 // Perform a full GC in order to ensure that we are not in the middle of an
967 // incremental marking phase when we are replacing the code object.
968 // Since we are not in an incremental marking phase we can write pointers
969 // to code objects (that are never in new space) without worrying about
970 // write barriers.
971 Heap* heap = original->GetHeap();
972 HeapIterator iterator(heap);
973
974 DCHECK(!heap->InNewSpace(*substitution));
975
976 ReplacingVisitor visitor(*original, *substitution);
977
978 // Iterate over all roots. Stack frames may have pointer into original code,
979 // so temporary replace the pointers with offset numbers
980 // in prologue/epilogue.
981 heap->IterateRoots(&visitor, VISIT_ALL);
982
983 // Now iterate over all pointers of all objects, including code_target
984 // implicit pointers.
985 for (HeapObject* obj = iterator.next(); obj != NULL; obj = iterator.next()) {
986 obj->Iterate(&visitor);
987 }
988 }
989
990
991 // Patch function literals.
992 // Name 'literals' is a misnomer. Rather it's a cache for complex object
993 // boilerplates and for a native context. We must clean cached values.
994 // Additionally we may need to allocate a new array if number of literals
995 // changed.
996 class LiteralFixer {
997 public:
998 static void PatchLiterals(FunctionInfoWrapper* compile_info_wrapper,
999 Handle<SharedFunctionInfo> shared_info,
1000 Isolate* isolate) {
1001 int new_literal_count = compile_info_wrapper->GetLiteralCount();
1002 int old_literal_count = shared_info->num_literals();
1003
1004 if (old_literal_count == new_literal_count) {
1005 // If literal count didn't change, simply go over all functions
1006 // and clear literal arrays.
1007 ClearValuesVisitor visitor;
1008 IterateJSFunctions(shared_info, &visitor);
1009 } else {
1010 // When literal count changes, we have to create new array instances.
1011 // Since we cannot create instances when iterating heap, we should first
1012 // collect all functions and fix their literal arrays.
1013 Handle<FixedArray> function_instances =
1014 CollectJSFunctions(shared_info, isolate);
1015 for (int i = 0; i < function_instances->length(); i++) {
1016 Handle<JSFunction> fun(JSFunction::cast(function_instances->get(i)));
1017 Handle<FixedArray> new_literals =
1018 isolate->factory()->NewFixedArray(new_literal_count);
1019 fun->set_literals(*new_literals);
1020 }
1021
1022 shared_info->set_num_literals(new_literal_count);
1023 }
1024 }
1025
1026 private:
1027 // Iterates all function instances in the HEAP that refers to the
1028 // provided shared_info.
1029 template<typename Visitor>
1030 static void IterateJSFunctions(Handle<SharedFunctionInfo> shared_info,
1031 Visitor* visitor) {
1032 HeapIterator iterator(shared_info->GetHeap());
1033 for (HeapObject* obj = iterator.next(); obj != NULL;
1034 obj = iterator.next()) {
1035 if (obj->IsJSFunction()) {
1036 JSFunction* function = JSFunction::cast(obj);
1037 if (function->shared() == *shared_info) {
1038 visitor->visit(function);
1039 }
1040 }
1041 }
1042 }
1043
1044 // Finds all instances of JSFunction that refers to the provided shared_info
1045 // and returns array with them.
1046 static Handle<FixedArray> CollectJSFunctions(
1047 Handle<SharedFunctionInfo> shared_info, Isolate* isolate) {
1048 CountVisitor count_visitor;
1049 count_visitor.count = 0;
1050 IterateJSFunctions(shared_info, &count_visitor);
1051 int size = count_visitor.count;
1052
1053 Handle<FixedArray> result = isolate->factory()->NewFixedArray(size);
1054 if (size > 0) {
1055 CollectVisitor collect_visitor(result);
1056 IterateJSFunctions(shared_info, &collect_visitor);
1057 }
1058 return result;
1059 }
1060
1061 class ClearValuesVisitor {
1062 public:
1063 void visit(JSFunction* fun) {
1064 FixedArray* literals = fun->literals();
1065 int len = literals->length();
1066 for (int j = 0; j < len; j++) {
1067 literals->set_undefined(j);
1068 }
1069 }
1070 };
1071
1072 class CountVisitor {
1073 public:
1074 void visit(JSFunction* fun) {
1075 count++;
1076 }
1077 int count;
1078 };
1079
1080 class CollectVisitor {
1081 public:
1082 explicit CollectVisitor(Handle<FixedArray> output)
1083 : m_output(output), m_pos(0) {}
1084
1085 void visit(JSFunction* fun) {
1086 m_output->set(m_pos, fun);
1087 m_pos++;
1088 }
1089 private:
1090 Handle<FixedArray> m_output;
1091 int m_pos;
1092 };
1093 };
1094
1095
1096 // Marks code that shares the same shared function info or has inlined
1097 // code that shares the same function info.
1098 class DependentFunctionMarker: public OptimizedFunctionVisitor {
1099 public:
1100 SharedFunctionInfo* shared_info_;
1101 bool found_;
1102
1103 explicit DependentFunctionMarker(SharedFunctionInfo* shared_info)
1104 : shared_info_(shared_info), found_(false) { }
1105
1106 virtual void EnterContext(Context* context) { } // Don't care.
1107 virtual void LeaveContext(Context* context) { } // Don't care.
1108 virtual void VisitFunction(JSFunction* function) {
1109 // It should be guaranteed by the iterator that everything is optimized.
1110 DCHECK(function->code()->kind() == Code::OPTIMIZED_FUNCTION);
1111 if (function->Inlines(shared_info_)) {
1112 // Mark the code for deoptimization.
1113 function->code()->set_marked_for_deoptimization(true);
1114 found_ = true;
1115 }
1116 }
1117 };
1118
1119
1120 static void DeoptimizeDependentFunctions(SharedFunctionInfo* function_info) {
1121 DisallowHeapAllocation no_allocation;
1122 DependentFunctionMarker marker(function_info);
1123 // TODO(titzer): need to traverse all optimized code to find OSR code here.
1124 Deoptimizer::VisitAllOptimizedFunctions(function_info->GetIsolate(), &marker);
1125
1126 if (marker.found_) {
1127 // Only go through with the deoptimization if something was found.
1128 Deoptimizer::DeoptimizeMarkedCode(function_info->GetIsolate());
1129 }
1130 }
1131
1132
1133 void LiveEdit::ReplaceFunctionCode(
1134 Handle<JSArray> new_compile_info_array,
1135 Handle<JSArray> shared_info_array) {
1136 Isolate* isolate = new_compile_info_array->GetIsolate();
1137
1138 FunctionInfoWrapper compile_info_wrapper(new_compile_info_array);
1139 SharedInfoWrapper shared_info_wrapper(shared_info_array);
1140
1141 Handle<SharedFunctionInfo> shared_info = shared_info_wrapper.GetInfo();
1142
1143 if (shared_info->code()->kind() == Code::FUNCTION) {
1144 Handle<Code> code = compile_info_wrapper.GetFunctionCode();
1145 ReplaceCodeObject(Handle<Code>(shared_info->code()), code);
1146 Handle<Object> code_scope_info = compile_info_wrapper.GetCodeScopeInfo();
1147 if (code_scope_info->IsFixedArray()) {
1148 shared_info->set_scope_info(ScopeInfo::cast(*code_scope_info));
1149 }
1150 shared_info->DisableOptimization(kLiveEdit);
1151 // Update the type feedback vector, if needed.
1152 MaybeHandle<TypeFeedbackVector> feedback_vector =
1153 compile_info_wrapper.GetFeedbackVector();
1154 if (!feedback_vector.is_null()) {
1155 shared_info->set_feedback_vector(*feedback_vector.ToHandleChecked());
1156 }
1157 }
1158
1159 int start_position = compile_info_wrapper.GetStartPosition();
1160 int end_position = compile_info_wrapper.GetEndPosition();
1161 shared_info->set_start_position(start_position);
1162 shared_info->set_end_position(end_position);
1163
1164 LiteralFixer::PatchLiterals(&compile_info_wrapper, shared_info, isolate);
1165
1166 shared_info->set_construct_stub(
1167 isolate->builtins()->builtin(Builtins::kJSConstructStubGeneric));
1168
1169 DeoptimizeDependentFunctions(*shared_info);
1170 isolate->compilation_cache()->Remove(shared_info);
1171 }
1172
1173
1174 void LiveEdit::FunctionSourceUpdated(Handle<JSArray> shared_info_array) {
1175 SharedInfoWrapper shared_info_wrapper(shared_info_array);
1176 Handle<SharedFunctionInfo> shared_info = shared_info_wrapper.GetInfo();
1177
1178 DeoptimizeDependentFunctions(*shared_info);
1179 shared_info_array->GetIsolate()->compilation_cache()->Remove(shared_info);
1180 }
1181
1182
1183 void LiveEdit::SetFunctionScript(Handle<JSValue> function_wrapper,
1184 Handle<Object> script_handle) {
1185 Handle<SharedFunctionInfo> shared_info =
1186 UnwrapSharedFunctionInfoFromJSValue(function_wrapper);
1187 CHECK(script_handle->IsScript() || script_handle->IsUndefined());
1188 SharedFunctionInfo::SetScript(shared_info, script_handle);
1189 shared_info->DisableOptimization(kLiveEdit);
1190
1191 function_wrapper->GetIsolate()->compilation_cache()->Remove(shared_info);
1192 }
1193
1194
1195 // For a script text change (defined as position_change_array), translates
1196 // position in unchanged text to position in changed text.
1197 // Text change is a set of non-overlapping regions in text, that have changed
1198 // their contents and length. It is specified as array of groups of 3 numbers:
1199 // (change_begin, change_end, change_end_new_position).
1200 // Each group describes a change in text; groups are sorted by change_begin.
1201 // Only position in text beyond any changes may be successfully translated.
1202 // If a positions is inside some region that changed, result is currently
1203 // undefined.
1204 static int TranslatePosition(int original_position,
1205 Handle<JSArray> position_change_array) {
1206 int position_diff = 0;
1207 int array_len = GetArrayLength(position_change_array);
1208 Isolate* isolate = position_change_array->GetIsolate();
1209 // TODO(635): binary search may be used here
1210 for (int i = 0; i < array_len; i += 3) {
1211 HandleScope scope(isolate);
1212 Handle<Object> element = Object::GetElement(
1213 isolate, position_change_array, i).ToHandleChecked();
1214 CHECK(element->IsSmi());
1215 int chunk_start = Handle<Smi>::cast(element)->value();
1216 if (original_position < chunk_start) {
1217 break;
1218 }
1219 element = Object::GetElement(
1220 isolate, position_change_array, i + 1).ToHandleChecked();
1221 CHECK(element->IsSmi());
1222 int chunk_end = Handle<Smi>::cast(element)->value();
1223 // Position mustn't be inside a chunk.
1224 DCHECK(original_position >= chunk_end);
1225 element = Object::GetElement(
1226 isolate, position_change_array, i + 2).ToHandleChecked();
1227 CHECK(element->IsSmi());
1228 int chunk_changed_end = Handle<Smi>::cast(element)->value();
1229 position_diff = chunk_changed_end - chunk_end;
1230 }
1231
1232 return original_position + position_diff;
1233 }
1234
1235
1236 // Auto-growing buffer for writing relocation info code section. This buffer
1237 // is a simplified version of buffer from Assembler. Unlike Assembler, this
1238 // class is platform-independent and it works without dealing with instructions.
1239 // As specified by RelocInfo format, the buffer is filled in reversed order:
1240 // from upper to lower addresses.
1241 // It uses NewArray/DeleteArray for memory management.
1242 class RelocInfoBuffer {
1243 public:
1244 RelocInfoBuffer(int buffer_initial_capicity, byte* pc) {
1245 buffer_size_ = buffer_initial_capicity + kBufferGap;
1246 buffer_ = NewArray<byte>(buffer_size_);
1247
1248 reloc_info_writer_.Reposition(buffer_ + buffer_size_, pc);
1249 }
1250 ~RelocInfoBuffer() {
1251 DeleteArray(buffer_);
1252 }
1253
1254 // As specified by RelocInfo format, the buffer is filled in reversed order:
1255 // from upper to lower addresses.
1256 void Write(const RelocInfo* rinfo) {
1257 if (buffer_ + kBufferGap >= reloc_info_writer_.pos()) {
1258 Grow();
1259 }
1260 reloc_info_writer_.Write(rinfo);
1261 }
1262
1263 Vector<byte> GetResult() {
1264 // Return the bytes from pos up to end of buffer.
1265 int result_size =
1266 static_cast<int>((buffer_ + buffer_size_) - reloc_info_writer_.pos());
1267 return Vector<byte>(reloc_info_writer_.pos(), result_size);
1268 }
1269
1270 private:
1271 void Grow() {
1272 // Compute new buffer size.
1273 int new_buffer_size;
1274 if (buffer_size_ < 2 * KB) {
1275 new_buffer_size = 4 * KB;
1276 } else {
1277 new_buffer_size = 2 * buffer_size_;
1278 }
1279 // Some internal data structures overflow for very large buffers,
1280 // they must ensure that kMaximalBufferSize is not too large.
1281 if (new_buffer_size > kMaximalBufferSize) {
1282 V8::FatalProcessOutOfMemory("RelocInfoBuffer::GrowBuffer");
1283 }
1284
1285 // Set up new buffer.
1286 byte* new_buffer = NewArray<byte>(new_buffer_size);
1287
1288 // Copy the data.
1289 int curently_used_size =
1290 static_cast<int>(buffer_ + buffer_size_ - reloc_info_writer_.pos());
1291 MemMove(new_buffer + new_buffer_size - curently_used_size,
1292 reloc_info_writer_.pos(), curently_used_size);
1293
1294 reloc_info_writer_.Reposition(
1295 new_buffer + new_buffer_size - curently_used_size,
1296 reloc_info_writer_.last_pc());
1297
1298 DeleteArray(buffer_);
1299 buffer_ = new_buffer;
1300 buffer_size_ = new_buffer_size;
1301 }
1302
1303 RelocInfoWriter reloc_info_writer_;
1304 byte* buffer_;
1305 int buffer_size_;
1306
1307 static const int kBufferGap = RelocInfoWriter::kMaxSize;
1308 static const int kMaximalBufferSize = 512*MB;
1309 };
1310
1311
1312 // Patch positions in code (changes relocation info section) and possibly
1313 // returns new instance of code.
1314 static Handle<Code> PatchPositionsInCode(
1315 Handle<Code> code,
1316 Handle<JSArray> position_change_array) {
1317 Isolate* isolate = code->GetIsolate();
1318
1319 RelocInfoBuffer buffer_writer(code->relocation_size(),
1320 code->instruction_start());
1321
1322 {
1323 for (RelocIterator it(*code); !it.done(); it.next()) {
1324 RelocInfo* rinfo = it.rinfo();
1325 if (RelocInfo::IsPosition(rinfo->rmode())) {
1326 int position = static_cast<int>(rinfo->data());
1327 int new_position = TranslatePosition(position,
1328 position_change_array);
1329 if (position != new_position) {
1330 RelocInfo info_copy(rinfo->pc(), rinfo->rmode(), new_position, NULL);
1331 buffer_writer.Write(&info_copy);
1332 continue;
1333 }
1334 }
1335 if (RelocInfo::IsRealRelocMode(rinfo->rmode())) {
1336 buffer_writer.Write(it.rinfo());
1337 }
1338 }
1339 }
1340
1341 Vector<byte> buffer = buffer_writer.GetResult();
1342
1343 if (buffer.length() == code->relocation_size()) {
1344 // Simply patch relocation area of code.
1345 MemCopy(code->relocation_start(), buffer.start(), buffer.length());
1346 return code;
1347 } else {
1348 // Relocation info section now has different size. We cannot simply
1349 // rewrite it inside code object. Instead we have to create a new
1350 // code object.
1351 Handle<Code> result(isolate->factory()->CopyCode(code, buffer));
1352 return result;
1353 }
1354 }
1355
1356
1357 void LiveEdit::PatchFunctionPositions(Handle<JSArray> shared_info_array,
1358 Handle<JSArray> position_change_array) {
1359 SharedInfoWrapper shared_info_wrapper(shared_info_array);
1360 Handle<SharedFunctionInfo> info = shared_info_wrapper.GetInfo();
1361
1362 int old_function_start = info->start_position();
1363 int new_function_start = TranslatePosition(old_function_start,
1364 position_change_array);
1365 int new_function_end = TranslatePosition(info->end_position(),
1366 position_change_array);
1367 int new_function_token_pos =
1368 TranslatePosition(info->function_token_position(), position_change_array);
1369
1370 info->set_start_position(new_function_start);
1371 info->set_end_position(new_function_end);
1372 info->set_function_token_position(new_function_token_pos);
1373
1374 if (info->code()->kind() == Code::FUNCTION) {
1375 // Patch relocation info section of the code.
1376 Handle<Code> patched_code = PatchPositionsInCode(Handle<Code>(info->code()),
1377 position_change_array);
1378 if (*patched_code != info->code()) {
1379 // Replace all references to the code across the heap. In particular,
1380 // some stubs may refer to this code and this code may be being executed
1381 // on stack (it is safe to substitute the code object on stack, because
1382 // we only change the structure of rinfo and leave instructions
1383 // untouched).
1384 ReplaceCodeObject(Handle<Code>(info->code()), patched_code);
1385 }
1386 }
1387 }
1388
1389
1390 static Handle<Script> CreateScriptCopy(Handle<Script> original) {
1391 Isolate* isolate = original->GetIsolate();
1392
1393 Handle<String> original_source(String::cast(original->source()));
1394 Handle<Script> copy = isolate->factory()->NewScript(original_source);
1395
1396 copy->set_name(original->name());
1397 copy->set_line_offset(original->line_offset());
1398 copy->set_column_offset(original->column_offset());
1399 copy->set_type(original->type());
1400 copy->set_context_data(original->context_data());
1401 copy->set_eval_from_shared(original->eval_from_shared());
1402 copy->set_eval_from_instructions_offset(
1403 original->eval_from_instructions_offset());
1404
1405 // Copy all the flags, but clear compilation state.
1406 copy->set_flags(original->flags());
1407 copy->set_compilation_state(Script::COMPILATION_STATE_INITIAL);
1408
1409 return copy;
1410 }
1411
1412
1413 Handle<Object> LiveEdit::ChangeScriptSource(Handle<Script> original_script,
1414 Handle<String> new_source,
1415 Handle<Object> old_script_name) {
1416 Isolate* isolate = original_script->GetIsolate();
1417 Handle<Object> old_script_object;
1418 if (old_script_name->IsString()) {
1419 Handle<Script> old_script = CreateScriptCopy(original_script);
1420 old_script->set_name(String::cast(*old_script_name));
1421 old_script_object = old_script;
1422 isolate->debug()->OnAfterCompile(old_script);
1423 } else {
1424 old_script_object = isolate->factory()->null_value();
1425 }
1426
1427 original_script->set_source(*new_source);
1428
1429 // Drop line ends so that they will be recalculated.
1430 original_script->set_line_ends(isolate->heap()->undefined_value());
1431
1432 return old_script_object;
1433 }
1434
1435
1436
1437 void LiveEdit::ReplaceRefToNestedFunction(
1438 Handle<JSValue> parent_function_wrapper,
1439 Handle<JSValue> orig_function_wrapper,
1440 Handle<JSValue> subst_function_wrapper) {
1441
1442 Handle<SharedFunctionInfo> parent_shared =
1443 UnwrapSharedFunctionInfoFromJSValue(parent_function_wrapper);
1444 Handle<SharedFunctionInfo> orig_shared =
1445 UnwrapSharedFunctionInfoFromJSValue(orig_function_wrapper);
1446 Handle<SharedFunctionInfo> subst_shared =
1447 UnwrapSharedFunctionInfoFromJSValue(subst_function_wrapper);
1448
1449 for (RelocIterator it(parent_shared->code()); !it.done(); it.next()) {
1450 if (it.rinfo()->rmode() == RelocInfo::EMBEDDED_OBJECT) {
1451 if (it.rinfo()->target_object() == *orig_shared) {
1452 it.rinfo()->set_target_object(*subst_shared);
1453 }
1454 }
1455 }
1456 }
1457
1458
1459 // Check an activation against list of functions. If there is a function
1460 // that matches, its status in result array is changed to status argument value.
1461 static bool CheckActivation(Handle<JSArray> shared_info_array,
1462 Handle<JSArray> result,
1463 StackFrame* frame,
1464 LiveEdit::FunctionPatchabilityStatus status) {
1465 if (!frame->is_java_script()) return false;
1466
1467 Handle<JSFunction> function(JavaScriptFrame::cast(frame)->function());
1468
1469 Isolate* isolate = shared_info_array->GetIsolate();
1470 int len = GetArrayLength(shared_info_array);
1471 for (int i = 0; i < len; i++) {
1472 HandleScope scope(isolate);
1473 Handle<Object> element =
1474 Object::GetElement(isolate, shared_info_array, i).ToHandleChecked();
1475 Handle<JSValue> jsvalue = Handle<JSValue>::cast(element);
1476 Handle<SharedFunctionInfo> shared =
1477 UnwrapSharedFunctionInfoFromJSValue(jsvalue);
1478
1479 if (function->Inlines(*shared)) {
1480 SetElementSloppy(result, i, Handle<Smi>(Smi::FromInt(status), isolate));
1481 return true;
1482 }
1483 }
1484 return false;
1485 }
1486
1487
1488 // Iterates over handler chain and removes all elements that are inside
1489 // frames being dropped.
1490 static bool FixTryCatchHandler(StackFrame* top_frame,
1491 StackFrame* bottom_frame) {
1492 Address* pointer_address =
1493 &Memory::Address_at(top_frame->isolate()->get_address_from_id(
1494 Isolate::kHandlerAddress));
1495
1496 while (*pointer_address < top_frame->sp()) {
1497 pointer_address = &Memory::Address_at(*pointer_address);
1498 }
1499 Address* above_frame_address = pointer_address;
1500 while (*pointer_address < bottom_frame->fp()) {
1501 pointer_address = &Memory::Address_at(*pointer_address);
1502 }
1503 bool change = *above_frame_address != *pointer_address;
1504 *above_frame_address = *pointer_address;
1505 return change;
1506 }
1507
1508
1509 // Initializes an artificial stack frame. The data it contains is used for:
1510 // a. successful work of frame dropper code which eventually gets control,
1511 // b. being compatible with regular stack structure for various stack
1512 // iterators.
1513 // Returns address of stack allocated pointer to restarted function,
1514 // the value that is called 'restarter_frame_function_pointer'. The value
1515 // at this address (possibly updated by GC) may be used later when preparing
1516 // 'step in' operation.
1517 // Frame structure (conforms InternalFrame structure):
1518 // -- code
1519 // -- SMI maker
1520 // -- function (slot is called "context")
1521 // -- frame base
1522 static Object** SetUpFrameDropperFrame(StackFrame* bottom_js_frame,
1523 Handle<Code> code) {
1524 DCHECK(bottom_js_frame->is_java_script());
1525
1526 Address fp = bottom_js_frame->fp();
1527
1528 // Move function pointer into "context" slot.
1529 Memory::Object_at(fp + StandardFrameConstants::kContextOffset) =
1530 Memory::Object_at(fp + JavaScriptFrameConstants::kFunctionOffset);
1531
1532 Memory::Object_at(fp + InternalFrameConstants::kCodeOffset) = *code;
1533 Memory::Object_at(fp + StandardFrameConstants::kMarkerOffset) =
1534 Smi::FromInt(StackFrame::INTERNAL);
1535
1536 return reinterpret_cast<Object**>(&Memory::Object_at(
1537 fp + StandardFrameConstants::kContextOffset));
1538 }
1539
1540
1541 // Removes specified range of frames from stack. There may be 1 or more
1542 // frames in range. Anyway the bottom frame is restarted rather than dropped,
1543 // and therefore has to be a JavaScript frame.
1544 // Returns error message or NULL.
1545 static const char* DropFrames(Vector<StackFrame*> frames,
1546 int top_frame_index,
1547 int bottom_js_frame_index,
1548 LiveEdit::FrameDropMode* mode,
1549 Object*** restarter_frame_function_pointer) {
1550 if (!LiveEdit::kFrameDropperSupported) {
1551 return "Stack manipulations are not supported in this architecture.";
1552 }
1553
1554 StackFrame* pre_top_frame = frames[top_frame_index - 1];
1555 StackFrame* top_frame = frames[top_frame_index];
1556 StackFrame* bottom_js_frame = frames[bottom_js_frame_index];
1557
1558 DCHECK(bottom_js_frame->is_java_script());
1559
1560 // Check the nature of the top frame.
1561 Isolate* isolate = bottom_js_frame->isolate();
1562 Code* pre_top_frame_code = pre_top_frame->LookupCode();
1563 bool frame_has_padding = true;
1564 if (pre_top_frame_code->is_inline_cache_stub() &&
1565 pre_top_frame_code->is_debug_stub()) {
1566 // OK, we can drop inline cache calls.
1567 *mode = LiveEdit::FRAME_DROPPED_IN_IC_CALL;
1568 } else if (pre_top_frame_code ==
1569 isolate->builtins()->builtin(Builtins::kSlot_DebugBreak)) {
1570 // OK, we can drop debug break slot.
1571 *mode = LiveEdit::FRAME_DROPPED_IN_DEBUG_SLOT_CALL;
1572 } else if (pre_top_frame_code ==
1573 isolate->builtins()->builtin(Builtins::kFrameDropper_LiveEdit)) {
1574 // OK, we can drop our own code.
1575 pre_top_frame = frames[top_frame_index - 2];
1576 top_frame = frames[top_frame_index - 1];
1577 *mode = LiveEdit::CURRENTLY_SET_MODE;
1578 frame_has_padding = false;
1579 } else if (pre_top_frame_code ==
1580 isolate->builtins()->builtin(Builtins::kReturn_DebugBreak)) {
1581 *mode = LiveEdit::FRAME_DROPPED_IN_RETURN_CALL;
1582 } else if (pre_top_frame_code->kind() == Code::STUB &&
1583 CodeStub::GetMajorKey(pre_top_frame_code) == CodeStub::CEntry) {
1584 // Entry from our unit tests on 'debugger' statement.
1585 // It's fine, we support this case.
1586 *mode = LiveEdit::FRAME_DROPPED_IN_DIRECT_CALL;
1587 // We don't have a padding from 'debugger' statement call.
1588 // Here the stub is CEntry, it's not debug-only and can't be padded.
1589 // If anyone would complain, a proxy padded stub could be added.
1590 frame_has_padding = false;
1591 } else if (pre_top_frame->type() == StackFrame::ARGUMENTS_ADAPTOR) {
1592 // This must be adaptor that remain from the frame dropping that
1593 // is still on stack. A frame dropper frame must be above it.
1594 DCHECK(frames[top_frame_index - 2]->LookupCode() ==
1595 isolate->builtins()->builtin(Builtins::kFrameDropper_LiveEdit));
1596 pre_top_frame = frames[top_frame_index - 3];
1597 top_frame = frames[top_frame_index - 2];
1598 *mode = LiveEdit::CURRENTLY_SET_MODE;
1599 frame_has_padding = false;
1600 } else {
1601 return "Unknown structure of stack above changing function";
1602 }
1603
1604 Address unused_stack_top = top_frame->sp();
1605 int new_frame_size = LiveEdit::kFrameDropperFrameSize * kPointerSize;
1606 Address unused_stack_bottom = bottom_js_frame->fp()
1607 - new_frame_size + kPointerSize; // Bigger address end is exclusive.
1608
1609 Address* top_frame_pc_address = top_frame->pc_address();
1610
1611 // top_frame may be damaged below this point. Do not used it.
1612 DCHECK(!(top_frame = NULL));
1613
1614 if (unused_stack_top > unused_stack_bottom) {
1615 if (frame_has_padding) {
1616 int shortage_bytes =
1617 static_cast<int>(unused_stack_top - unused_stack_bottom);
1618
1619 Address padding_start = pre_top_frame->fp() -
1620 LiveEdit::kFrameDropperFrameSize * kPointerSize;
1621
1622 Address padding_pointer = padding_start;
1623 Smi* padding_object = Smi::FromInt(LiveEdit::kFramePaddingValue);
1624 while (Memory::Object_at(padding_pointer) == padding_object) {
1625 padding_pointer -= kPointerSize;
1626 }
1627 int padding_counter =
1628 Smi::cast(Memory::Object_at(padding_pointer))->value();
1629 if (padding_counter * kPointerSize < shortage_bytes) {
1630 return "Not enough space for frame dropper frame "
1631 "(even with padding frame)";
1632 }
1633 Memory::Object_at(padding_pointer) =
1634 Smi::FromInt(padding_counter - shortage_bytes / kPointerSize);
1635
1636 StackFrame* pre_pre_frame = frames[top_frame_index - 2];
1637
1638 MemMove(padding_start + kPointerSize - shortage_bytes,
1639 padding_start + kPointerSize,
1640 LiveEdit::kFrameDropperFrameSize * kPointerSize);
1641
1642 pre_top_frame->UpdateFp(pre_top_frame->fp() - shortage_bytes);
1643 pre_pre_frame->SetCallerFp(pre_top_frame->fp());
1644 unused_stack_top -= shortage_bytes;
1645
1646 STATIC_ASSERT(sizeof(Address) == kPointerSize);
1647 top_frame_pc_address -= shortage_bytes / kPointerSize;
1648 } else {
1649 return "Not enough space for frame dropper frame";
1650 }
1651 }
1652
1653 // Committing now. After this point we should return only NULL value.
1654
1655 FixTryCatchHandler(pre_top_frame, bottom_js_frame);
1656 // Make sure FixTryCatchHandler is idempotent.
1657 DCHECK(!FixTryCatchHandler(pre_top_frame, bottom_js_frame));
1658
1659 Handle<Code> code = isolate->builtins()->FrameDropper_LiveEdit();
1660 *top_frame_pc_address = code->entry();
1661 pre_top_frame->SetCallerFp(bottom_js_frame->fp());
1662
1663 *restarter_frame_function_pointer =
1664 SetUpFrameDropperFrame(bottom_js_frame, code);
1665
1666 DCHECK((**restarter_frame_function_pointer)->IsJSFunction());
1667
1668 for (Address a = unused_stack_top;
1669 a < unused_stack_bottom;
1670 a += kPointerSize) {
1671 Memory::Object_at(a) = Smi::FromInt(0);
1672 }
1673
1674 return NULL;
1675 }
1676
1677
1678 // Describes a set of call frames that execute any of listed functions.
1679 // Finding no such frames does not mean error.
1680 class MultipleFunctionTarget {
1681 public:
1682 MultipleFunctionTarget(Handle<JSArray> shared_info_array,
1683 Handle<JSArray> result)
1684 : m_shared_info_array(shared_info_array),
1685 m_result(result) {}
1686 bool MatchActivation(StackFrame* frame,
1687 LiveEdit::FunctionPatchabilityStatus status) {
1688 return CheckActivation(m_shared_info_array, m_result, frame, status);
1689 }
1690 const char* GetNotFoundMessage() const {
1691 return NULL;
1692 }
1693 private:
1694 Handle<JSArray> m_shared_info_array;
1695 Handle<JSArray> m_result;
1696 };
1697
1698
1699 // Drops all call frame matched by target and all frames above them.
1700 template <typename TARGET>
1701 static const char* DropActivationsInActiveThreadImpl(Isolate* isolate,
1702 TARGET& target, // NOLINT
1703 bool do_drop) {
1704 Debug* debug = isolate->debug();
1705 Zone zone;
1706 Vector<StackFrame*> frames = CreateStackMap(isolate, &zone);
1707
1708
1709 int top_frame_index = -1;
1710 int frame_index = 0;
1711 for (; frame_index < frames.length(); frame_index++) {
1712 StackFrame* frame = frames[frame_index];
1713 if (frame->id() == debug->break_frame_id()) {
1714 top_frame_index = frame_index;
1715 break;
1716 }
1717 if (target.MatchActivation(
1718 frame, LiveEdit::FUNCTION_BLOCKED_UNDER_NATIVE_CODE)) {
1719 // We are still above break_frame. It is not a target frame,
1720 // it is a problem.
1721 return "Debugger mark-up on stack is not found";
1722 }
1723 }
1724
1725 if (top_frame_index == -1) {
1726 // We haven't found break frame, but no function is blocking us anyway.
1727 return target.GetNotFoundMessage();
1728 }
1729
1730 bool target_frame_found = false;
1731 int bottom_js_frame_index = top_frame_index;
1732 bool non_droppable_frame_found = false;
1733 LiveEdit::FunctionPatchabilityStatus non_droppable_reason;
1734
1735 for (; frame_index < frames.length(); frame_index++) {
1736 StackFrame* frame = frames[frame_index];
1737 if (frame->is_exit()) {
1738 non_droppable_frame_found = true;
1739 non_droppable_reason = LiveEdit::FUNCTION_BLOCKED_UNDER_NATIVE_CODE;
1740 break;
1741 }
1742 if (frame->is_java_script() &&
1743 JavaScriptFrame::cast(frame)->function()->shared()->is_generator()) {
1744 non_droppable_frame_found = true;
1745 non_droppable_reason = LiveEdit::FUNCTION_BLOCKED_UNDER_GENERATOR;
1746 break;
1747 }
1748 if (target.MatchActivation(
1749 frame, LiveEdit::FUNCTION_BLOCKED_ON_ACTIVE_STACK)) {
1750 target_frame_found = true;
1751 bottom_js_frame_index = frame_index;
1752 }
1753 }
1754
1755 if (non_droppable_frame_found) {
1756 // There is a C or generator frame on stack. We can't drop C frames, and we
1757 // can't restart generators. Check that there are no target frames below
1758 // them.
1759 for (; frame_index < frames.length(); frame_index++) {
1760 StackFrame* frame = frames[frame_index];
1761 if (frame->is_java_script()) {
1762 if (target.MatchActivation(frame, non_droppable_reason)) {
1763 // Fail.
1764 return NULL;
1765 }
1766 }
1767 }
1768 }
1769
1770 if (!do_drop) {
1771 // We are in check-only mode.
1772 return NULL;
1773 }
1774
1775 if (!target_frame_found) {
1776 // Nothing to drop.
1777 return target.GetNotFoundMessage();
1778 }
1779
1780 LiveEdit::FrameDropMode drop_mode = LiveEdit::FRAMES_UNTOUCHED;
1781 Object** restarter_frame_function_pointer = NULL;
1782 const char* error_message = DropFrames(frames, top_frame_index,
1783 bottom_js_frame_index, &drop_mode,
1784 &restarter_frame_function_pointer);
1785
1786 if (error_message != NULL) {
1787 return error_message;
1788 }
1789
1790 // Adjust break_frame after some frames has been dropped.
1791 StackFrame::Id new_id = StackFrame::NO_ID;
1792 for (int i = bottom_js_frame_index + 1; i < frames.length(); i++) {
1793 if (frames[i]->type() == StackFrame::JAVA_SCRIPT) {
1794 new_id = frames[i]->id();
1795 break;
1796 }
1797 }
1798 debug->FramesHaveBeenDropped(
1799 new_id, drop_mode, restarter_frame_function_pointer);
1800 return NULL;
1801 }
1802
1803
1804 // Fills result array with statuses of functions. Modifies the stack
1805 // removing all listed function if possible and if do_drop is true.
1806 static const char* DropActivationsInActiveThread(
1807 Handle<JSArray> shared_info_array, Handle<JSArray> result, bool do_drop) {
1808 MultipleFunctionTarget target(shared_info_array, result);
1809 Isolate* isolate = shared_info_array->GetIsolate();
1810
1811 const char* message =
1812 DropActivationsInActiveThreadImpl(isolate, target, do_drop);
1813 if (message) {
1814 return message;
1815 }
1816
1817 int array_len = GetArrayLength(shared_info_array);
1818
1819 // Replace "blocked on active" with "replaced on active" status.
1820 for (int i = 0; i < array_len; i++) {
1821 Handle<Object> obj =
1822 Object::GetElement(isolate, result, i).ToHandleChecked();
1823 if (*obj == Smi::FromInt(LiveEdit::FUNCTION_BLOCKED_ON_ACTIVE_STACK)) {
1824 Handle<Object> replaced(
1825 Smi::FromInt(LiveEdit::FUNCTION_REPLACED_ON_ACTIVE_STACK), isolate);
1826 SetElementSloppy(result, i, replaced);
1827 }
1828 }
1829 return NULL;
1830 }
1831
1832
1833 bool LiveEdit::FindActiveGenerators(Handle<FixedArray> shared_info_array,
1834 Handle<FixedArray> result,
1835 int len) {
1836 Isolate* isolate = shared_info_array->GetIsolate();
1837 bool found_suspended_activations = false;
1838
1839 DCHECK_LE(len, result->length());
1840
1841 FunctionPatchabilityStatus active = FUNCTION_BLOCKED_ACTIVE_GENERATOR;
1842
1843 Heap* heap = isolate->heap();
1844 HeapIterator iterator(heap);
1845 HeapObject* obj = NULL;
1846 while ((obj = iterator.next()) != NULL) {
1847 if (!obj->IsJSGeneratorObject()) continue;
1848
1849 JSGeneratorObject* gen = JSGeneratorObject::cast(obj);
1850 if (gen->is_closed()) continue;
1851
1852 HandleScope scope(isolate);
1853
1854 for (int i = 0; i < len; i++) {
1855 Handle<JSValue> jsvalue =
1856 Handle<JSValue>::cast(FixedArray::get(shared_info_array, i));
1857 Handle<SharedFunctionInfo> shared =
1858 UnwrapSharedFunctionInfoFromJSValue(jsvalue);
1859
1860 if (gen->function()->shared() == *shared) {
1861 result->set(i, Smi::FromInt(active));
1862 found_suspended_activations = true;
1863 }
1864 }
1865 }
1866
1867 return found_suspended_activations;
1868 }
1869
1870
1871 class InactiveThreadActivationsChecker : public ThreadVisitor {
1872 public:
1873 InactiveThreadActivationsChecker(Handle<JSArray> shared_info_array,
1874 Handle<JSArray> result)
1875 : shared_info_array_(shared_info_array), result_(result),
1876 has_blocked_functions_(false) {
1877 }
1878 void VisitThread(Isolate* isolate, ThreadLocalTop* top) {
1879 for (StackFrameIterator it(isolate, top); !it.done(); it.Advance()) {
1880 has_blocked_functions_ |= CheckActivation(
1881 shared_info_array_, result_, it.frame(),
1882 LiveEdit::FUNCTION_BLOCKED_ON_OTHER_STACK);
1883 }
1884 }
1885 bool HasBlockedFunctions() {
1886 return has_blocked_functions_;
1887 }
1888
1889 private:
1890 Handle<JSArray> shared_info_array_;
1891 Handle<JSArray> result_;
1892 bool has_blocked_functions_;
1893 };
1894
1895
1896 Handle<JSArray> LiveEdit::CheckAndDropActivations(
1897 Handle<JSArray> shared_info_array, bool do_drop) {
1898 Isolate* isolate = shared_info_array->GetIsolate();
1899 int len = GetArrayLength(shared_info_array);
1900
1901 DCHECK(shared_info_array->HasFastElements());
1902 Handle<FixedArray> shared_info_array_elements(
1903 FixedArray::cast(shared_info_array->elements()));
1904
1905 Handle<JSArray> result = isolate->factory()->NewJSArray(len);
1906 Handle<FixedArray> result_elements =
1907 JSObject::EnsureWritableFastElements(result);
1908
1909 // Fill the default values.
1910 for (int i = 0; i < len; i++) {
1911 FunctionPatchabilityStatus status = FUNCTION_AVAILABLE_FOR_PATCH;
1912 result_elements->set(i, Smi::FromInt(status));
1913 }
1914
1915 // Scan the heap for active generators -- those that are either currently
1916 // running (as we wouldn't want to restart them, because we don't know where
1917 // to restart them from) or suspended. Fail if any one corresponds to the set
1918 // of functions being edited.
1919 if (FindActiveGenerators(shared_info_array_elements, result_elements, len)) {
1920 return result;
1921 }
1922
1923 // Check inactive threads. Fail if some functions are blocked there.
1924 InactiveThreadActivationsChecker inactive_threads_checker(shared_info_array,
1925 result);
1926 isolate->thread_manager()->IterateArchivedThreads(
1927 &inactive_threads_checker);
1928 if (inactive_threads_checker.HasBlockedFunctions()) {
1929 return result;
1930 }
1931
1932 // Try to drop activations from the current stack.
1933 const char* error_message =
1934 DropActivationsInActiveThread(shared_info_array, result, do_drop);
1935 if (error_message != NULL) {
1936 // Add error message as an array extra element.
1937 Handle<String> str =
1938 isolate->factory()->NewStringFromAsciiChecked(error_message);
1939 SetElementSloppy(result, len, str);
1940 }
1941 return result;
1942 }
1943
1944
1945 // Describes a single callframe a target. Not finding this frame
1946 // means an error.
1947 class SingleFrameTarget {
1948 public:
1949 explicit SingleFrameTarget(JavaScriptFrame* frame)
1950 : m_frame(frame),
1951 m_saved_status(LiveEdit::FUNCTION_AVAILABLE_FOR_PATCH) {}
1952
1953 bool MatchActivation(StackFrame* frame,
1954 LiveEdit::FunctionPatchabilityStatus status) {
1955 if (frame->fp() == m_frame->fp()) {
1956 m_saved_status = status;
1957 return true;
1958 }
1959 return false;
1960 }
1961 const char* GetNotFoundMessage() const {
1962 return "Failed to found requested frame";
1963 }
1964 LiveEdit::FunctionPatchabilityStatus saved_status() {
1965 return m_saved_status;
1966 }
1967 private:
1968 JavaScriptFrame* m_frame;
1969 LiveEdit::FunctionPatchabilityStatus m_saved_status;
1970 };
1971
1972
1973 // Finds a drops required frame and all frames above.
1974 // Returns error message or NULL.
1975 const char* LiveEdit::RestartFrame(JavaScriptFrame* frame) {
1976 SingleFrameTarget target(frame);
1977
1978 const char* result =
1979 DropActivationsInActiveThreadImpl(frame->isolate(), target, true);
1980 if (result != NULL) {
1981 return result;
1982 }
1983 if (target.saved_status() == LiveEdit::FUNCTION_BLOCKED_UNDER_NATIVE_CODE) {
1984 return "Function is blocked under native code";
1985 }
1986 if (target.saved_status() == LiveEdit::FUNCTION_BLOCKED_UNDER_GENERATOR) {
1987 return "Function is blocked under a generator activation";
1988 }
1989 return NULL;
1990 }
1991
1992
1993 LiveEditFunctionTracker::LiveEditFunctionTracker(Isolate* isolate,
1994 FunctionLiteral* fun)
1995 : isolate_(isolate) {
1996 if (isolate_->active_function_info_listener() != NULL) {
1997 isolate_->active_function_info_listener()->FunctionStarted(fun);
1998 }
1999 }
2000
2001
2002 LiveEditFunctionTracker::~LiveEditFunctionTracker() {
2003 if (isolate_->active_function_info_listener() != NULL) {
2004 isolate_->active_function_info_listener()->FunctionDone();
2005 }
2006 }
2007
2008
2009 void LiveEditFunctionTracker::RecordFunctionInfo(
2010 Handle<SharedFunctionInfo> info, FunctionLiteral* lit,
2011 Zone* zone) {
2012 if (isolate_->active_function_info_listener() != NULL) {
2013 isolate_->active_function_info_listener()->FunctionInfo(info, lit->scope(),
2014 zone);
2015 }
2016 }
2017
2018
2019 void LiveEditFunctionTracker::RecordRootFunctionInfo(Handle<Code> code) {
2020 isolate_->active_function_info_listener()->FunctionCode(code);
2021 }
2022
2023
2024 bool LiveEditFunctionTracker::IsActive(Isolate* isolate) {
2025 return isolate->active_function_info_listener() != NULL;
2026 }
2027
2028 } // namespace internal
2029 } // namespace v8
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