LCOV - code coverage report
Current view: top level - src - handles.cc (source / functions) Hit Total Coverage
Test: app.info Lines: 74 75 98.7 %
Date: 2017-04-26 Functions: 13 13 100.0 %

          Line data    Source code
       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             : #include "src/handles.h"
       6             : 
       7             : #include "src/address-map.h"
       8             : #include "src/base/logging.h"
       9             : #include "src/identity-map.h"
      10             : #include "src/objects-inl.h"
      11             : 
      12             : namespace v8 {
      13             : namespace internal {
      14             : 
      15             : #ifdef DEBUG
      16             : bool HandleBase::IsDereferenceAllowed(DereferenceCheckMode mode) const {
      17             :   DCHECK_NOT_NULL(location_);
      18             :   Object* object = *location_;
      19             :   if (object->IsSmi()) return true;
      20             :   HeapObject* heap_object = HeapObject::cast(object);
      21             :   Heap* heap = heap_object->GetHeap();
      22             :   Object** roots_array_start = heap->roots_array_start();
      23             :   if (roots_array_start <= location_ &&
      24             :       location_ < roots_array_start + Heap::kStrongRootListLength &&
      25             :       heap->RootCanBeTreatedAsConstant(
      26             :           static_cast<Heap::RootListIndex>(location_ - roots_array_start))) {
      27             :     return true;
      28             :   }
      29             :   if (!AllowHandleDereference::IsAllowed()) return false;
      30             :   if (mode == INCLUDE_DEFERRED_CHECK &&
      31             :       !AllowDeferredHandleDereference::IsAllowed()) {
      32             :     // Accessing cells, maps and internalized strings is safe.
      33             :     if (heap_object->IsCell()) return true;
      34             :     if (heap_object->IsMap()) return true;
      35             :     if (heap_object->IsInternalizedString()) return true;
      36             :     return !heap->isolate()->IsDeferredHandle(location_);
      37             :   }
      38             :   return true;
      39             : }
      40             : #endif
      41             : 
      42             : 
      43        7068 : int HandleScope::NumberOfHandles(Isolate* isolate) {
      44             :   HandleScopeImplementer* impl = isolate->handle_scope_implementer();
      45        7068 :   int n = impl->blocks()->length();
      46        7068 :   if (n == 0) return 0;
      47       14094 :   return ((n - 1) * kHandleBlockSize) + static_cast<int>(
      48       21141 :       (isolate->handle_scope_data()->next - impl->blocks()->last()));
      49             : }
      50             : 
      51             : 
      52     3669992 : Object** HandleScope::Extend(Isolate* isolate) {
      53             :   HandleScopeData* current = isolate->handle_scope_data();
      54             : 
      55     1834996 :   Object** result = current->next;
      56             : 
      57             :   DCHECK(result == current->limit);
      58             :   // Make sure there's at least one scope on the stack and that the
      59             :   // top of the scope stack isn't a barrier.
      60     1834996 :   if (!Utils::ApiCheck(current->level != current->sealed_level,
      61             :                        "v8::HandleScope::CreateHandle()",
      62     1834996 :                        "Cannot create a handle without a HandleScope")) {
      63             :     return NULL;
      64             :   }
      65             :   HandleScopeImplementer* impl = isolate->handle_scope_implementer();
      66             :   // If there's more room in the last block, we use that. This is used
      67             :   // for fast creation of scopes after scope barriers.
      68     1834996 :   if (!impl->blocks()->is_empty()) {
      69             :     Object** limit = &impl->blocks()->last()[kHandleBlockSize];
      70      985217 :     if (current->limit != limit) {
      71           0 :       current->limit = limit;
      72             :       DCHECK(limit - current->next < kHandleBlockSize);
      73             :     }
      74             :   }
      75             : 
      76             :   // If we still haven't found a slot for the handle, we extend the
      77             :   // current handle scope by allocating a new handle block.
      78     1834996 :   if (result == current->limit) {
      79             :     // If there's a spare block, use it for growing the current scope.
      80             :     result = impl->GetSpareOrNewBlock();
      81             :     // Add the extension to the global list of blocks, but count the
      82             :     // extension as part of the current scope.
      83     1834996 :     impl->blocks()->Add(result);
      84     1834994 :     current->limit = &result[kHandleBlockSize];
      85             :   }
      86             : 
      87     1834994 :   return result;
      88             : }
      89             : 
      90             : 
      91     3095212 : void HandleScope::DeleteExtensions(Isolate* isolate) {
      92             :   HandleScopeData* current = isolate->handle_scope_data();
      93     3095212 :   isolate->handle_scope_implementer()->DeleteExtensions(current->limit);
      94     1547613 : }
      95             : 
      96             : 
      97             : #ifdef ENABLE_HANDLE_ZAPPING
      98  1392301871 : void HandleScope::ZapRange(Object** start, Object** end) {
      99             :   DCHECK(end - start <= kHandleBlockSize);
     100  6228732521 :   for (Object** p = start; p != end; p++) {
     101  4836430650 :     *reinterpret_cast<Address*>(p) = kHandleZapValue;
     102             :   }
     103  1392301871 : }
     104             : #endif
     105             : 
     106             : 
     107       67218 : Address HandleScope::current_level_address(Isolate* isolate) {
     108       67218 :   return reinterpret_cast<Address>(&isolate->handle_scope_data()->level);
     109             : }
     110             : 
     111             : 
     112       67218 : Address HandleScope::current_next_address(Isolate* isolate) {
     113       67218 :   return reinterpret_cast<Address>(&isolate->handle_scope_data()->next);
     114             : }
     115             : 
     116             : 
     117       67218 : Address HandleScope::current_limit_address(Isolate* isolate) {
     118       67218 :   return reinterpret_cast<Address>(&isolate->handle_scope_data()->limit);
     119             : }
     120             : 
     121      791226 : CanonicalHandleScope::CanonicalHandleScope(Isolate* isolate)
     122      791226 :     : isolate_(isolate), zone_(isolate->allocator(), ZONE_NAME) {
     123      395613 :   HandleScopeData* handle_scope_data = isolate_->handle_scope_data();
     124      395613 :   prev_canonical_scope_ = handle_scope_data->canonical_scope;
     125      395613 :   handle_scope_data->canonical_scope = this;
     126      395613 :   root_index_map_ = new RootIndexMap(isolate);
     127             :   identity_map_ = new IdentityMap<Object**, ZoneAllocationPolicy>(
     128      791226 :       isolate->heap(), ZoneAllocationPolicy(&zone_));
     129      395613 :   canonical_level_ = handle_scope_data->level;
     130      395613 : }
     131             : 
     132             : 
     133      791225 : CanonicalHandleScope::~CanonicalHandleScope() {
     134      395612 :   delete root_index_map_;
     135      395613 :   delete identity_map_;
     136      395613 :   isolate_->handle_scope_data()->canonical_scope = prev_canonical_scope_;
     137      395613 : }
     138             : 
     139             : 
     140    27263134 : Object** CanonicalHandleScope::Lookup(Object* object) {
     141             :   DCHECK_LE(canonical_level_, isolate_->handle_scope_data()->level);
     142    27263134 :   if (isolate_->handle_scope_data()->level != canonical_level_) {
     143             :     // We are in an inner handle scope. Do not canonicalize since we will leave
     144             :     // this handle scope while still being in the canonical scope.
     145      287760 :     return HandleScope::CreateHandle(isolate_, object);
     146             :   }
     147    26975374 :   if (object->IsHeapObject()) {
     148    22996921 :     int index = root_index_map_->Lookup(HeapObject::cast(object));
     149    22996967 :     if (index != RootIndexMap::kInvalidRootIndex) {
     150             :       return isolate_->heap()
     151     1325343 :           ->root_handle(static_cast<Heap::RootListIndex>(index))
     152             :           .location();
     153             :     }
     154             :   }
     155    25650077 :   Object*** entry = identity_map_->Get(object);
     156    25649988 :   if (*entry == nullptr) {
     157             :     // Allocate new handle location.
     158    28971524 :     *entry = HandleScope::CreateHandle(isolate_, object);
     159             :   }
     160    25649990 :   return reinterpret_cast<Object**>(*entry);
     161             : }
     162             : 
     163             : 
     164      150621 : DeferredHandleScope::DeferredHandleScope(Isolate* isolate)
     165      150621 :     : impl_(isolate->handle_scope_implementer()) {
     166      301242 :   impl_->BeginDeferredScope();
     167      150621 :   HandleScopeData* data = impl_->isolate()->handle_scope_data();
     168             :   Object** new_next = impl_->GetSpareOrNewBlock();
     169      150621 :   Object** new_limit = &new_next[kHandleBlockSize];
     170             :   // Check that at least one HandleScope exists, see the class description.
     171             :   DCHECK(!impl_->blocks()->is_empty());
     172             :   // Check that we are not in a SealedHandleScope.
     173             :   DCHECK(data->limit == &impl_->blocks()->last()[kHandleBlockSize]);
     174      150621 :   impl_->blocks()->Add(new_next);
     175             : 
     176             : #ifdef DEBUG
     177             :   prev_level_ = data->level;
     178             : #endif
     179      150621 :   data->level++;
     180      150621 :   prev_limit_ = data->limit;
     181      150621 :   prev_next_ = data->next;
     182      150621 :   data->next = new_next;
     183      150621 :   data->limit = new_limit;
     184      150621 : }
     185             : 
     186             : 
     187      150621 : DeferredHandleScope::~DeferredHandleScope() {
     188      150621 :   impl_->isolate()->handle_scope_data()->level--;
     189             :   DCHECK(handles_detached_);
     190             :   DCHECK(impl_->isolate()->handle_scope_data()->level == prev_level_);
     191      150621 : }
     192             : 
     193             : 
     194      150621 : DeferredHandles* DeferredHandleScope::Detach() {
     195      301242 :   DeferredHandles* deferred = impl_->Detach(prev_limit_);
     196      150621 :   HandleScopeData* data = impl_->isolate()->handle_scope_data();
     197      150621 :   data->next = prev_next_;
     198      150621 :   data->limit = prev_limit_;
     199             : #ifdef DEBUG
     200             :   handles_detached_ = true;
     201             : #endif
     202      150621 :   return deferred;
     203             : }
     204             : 
     205             : }  // namespace internal
     206             : }  // namespace v8

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