AddToOptimizedCodeMapInternal.cc

// from https://raw.githubusercontent.com/v8/v8/master/src/objects.cc

void SharedFunctionInfo::AddToOptimizedCodeMapInternal(
    Handle<SharedFunctionInfo> shared, Handle<Context> native_context,
    Handle<HeapObject> code, Handle<LiteralsArray> literals,
    BailoutId osr_ast_id) {
  Isolate* isolate = shared->GetIsolate();
  if (isolate->serializer_enabled()) return;
  DCHECK(*code == isolate->heap()->undefined_value() ||
         !shared->SearchOptimizedCodeMap(*native_context, osr_ast_id).code);
  DCHECK(*code == isolate->heap()->undefined_value() ||
         Code::cast(*code)->kind() == Code::OPTIMIZED_FUNCTION);
  DCHECK(native_context->IsNativeContext());
  STATIC_ASSERT(kEntryLength == 4);
  Handle<FixedArray> new_code_map;
  int entry;

  if (shared->OptimizedCodeMapIsCleared()) {
    new_code_map = isolate->factory()->NewFixedArray(kInitialLength, TENURED);
    new_code_map->set(kSharedCodeIndex, *isolate->factory()->empty_weak_cell(),
                      SKIP_WRITE_BARRIER);
    entry = kEntriesStart;
  } else {
    Handle<FixedArray> old_code_map(shared->optimized_code_map(), isolate);
    entry = shared->SearchOptimizedCodeMapEntry(*native_context, osr_ast_id);
    if (entry > kSharedCodeIndex) {
      // Found an existing context-specific entry. If the user provided valid
      // code, it must not contain any code.
      DCHECK(code->IsUndefined() ||
             WeakCell::cast(old_code_map->get(entry + kCachedCodeOffset))
                 ->cleared());

      // Just set the code and literals to the entry.
      if (!code->IsUndefined()) {
        Handle<WeakCell> code_cell = isolate->factory()->NewWeakCell(code);
        old_code_map->set(entry + kCachedCodeOffset, *code_cell);
      }
      Handle<WeakCell> literals_cell =
          isolate->factory()->NewWeakCell(literals);
      old_code_map->set(entry + kLiteralsOffset, *literals_cell);
      return;
    }

    // Can we reuse an entry?
    DCHECK(entry < kEntriesStart);
    int length = old_code_map->length();
    for (int i = kEntriesStart; i < length; i += kEntryLength) {
      if (WeakCell::cast(old_code_map->get(i + kContextOffset))->cleared()) {
        new_code_map = old_code_map;
        entry = i;
        break;
      }
    }

    if (entry < kEntriesStart) {
      // Copy old optimized code map and append one new entry.
      new_code_map = isolate->factory()->CopyFixedArrayAndGrow(
          old_code_map, kEntryLength, TENURED);
      // TODO(mstarzinger): Temporary workaround. The allocation above might
      // have flushed the optimized code map and the copy we created is full of
      // holes. For now we just give up on adding the entry and pretend it got
      // flushed.
      if (shared->OptimizedCodeMapIsCleared()) return;
      entry = old_code_map->length();
    }
  }

  Handle<WeakCell> code_cell = code->IsUndefined()
                                   ? isolate->factory()->empty_weak_cell()
                                   : isolate->factory()->NewWeakCell(code);
  Handle<WeakCell> literals_cell = isolate->factory()->NewWeakCell(literals);
  WeakCell* context_cell = native_context->self_weak_cell();

  new_code_map->set(entry + kContextOffset, context_cell);
  new_code_map->set(entry + kCachedCodeOffset, *code_cell);
  new_code_map->set(entry + kLiteralsOffset, *literals_cell);
  new_code_map->set(entry + kOsrAstIdOffset, Smi::FromInt(osr_ast_id.ToInt()));

#ifdef DEBUG
  for (int i = kEntriesStart; i < new_code_map->length(); i += kEntryLength) {
    WeakCell* cell = WeakCell::cast(new_code_map->get(i + kContextOffset));
    DCHECK(cell->cleared() || cell->value()->IsNativeContext());
    cell = WeakCell::cast(new_code_map->get(i + kCachedCodeOffset));
    DCHECK(cell->cleared() ||
           (cell->value()->IsCode() &&
            Code::cast(cell->value())->kind() == Code::OPTIMIZED_FUNCTION));
    cell = WeakCell::cast(new_code_map->get(i + kLiteralsOffset));
    DCHECK(cell->cleared() || cell->value()->IsFixedArray());
    DCHECK(new_code_map->get(i + kOsrAstIdOffset)->IsSmi());
  }
#endif

  FixedArray* old_code_map = shared->optimized_code_map();
  if (old_code_map != *new_code_map) {
    shared->set_optimized_code_map(*new_code_map);
  }
}