[handle] Zap local and persistent handles

Zap freed local and persistent handles similar to main thread handles.
As a drive-by change, fix the creation of local handles without
LocalHandleScope.

Bug: v8:10315
Change-Id: Ia71bc5419c62ae073928751f57fc221ea11de254
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2323362
Commit-Queue: Dominik Inführ <dinfuehr@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#69121}

src/handles/handles.h

@@ -264,6 +264,8 @@ class HandleScope {
   friend class DeferredHandleScope;
   friend class HandleScopeImplementer;
   friend class Isolate;
+  friend class LocalHandles;
+  friend class PersistentHandles;
 
   DISALLOW_COPY_AND_ASSIGN(HandleScope);
 };

src/handles/local-handles-inl.h

@@ -43,11 +43,13 @@ LocalHandleScope::~LocalHandleScope() {
   handles->scope_.level--;
 
   if (old_limit != handles->scope_.limit) {
-    handles->RemoveBlocks();
+    handles->RemoveUnusedBlocks();
     old_limit = handles->scope_.limit;
   }
 
-  // TODO(dinfuehr): Zap handles
+#ifdef ENABLE_HANDLE_ZAPPING
+  LocalHandles::ZapRange(handles->scope_.next, old_limit);
+#endif
 
   MSAN_ALLOCATED_UNINITIALIZED_MEMORY(
       handles->scope_.next,

src/handles/local-handles.cc

@@ -11,6 +11,11 @@ namespace v8 {
 namespace internal {
 
 LocalHandles::LocalHandles() { scope_.Initialize(); }
+LocalHandles::~LocalHandles() {
+  scope_.limit = nullptr;
+  RemoveUnusedBlocks();
+  DCHECK(blocks_.empty());
+}
 
 void LocalHandles::Iterate(RootVisitor* visitor) {
   for (int i = 0; i < static_cast<int>(blocks_.size()) - 1; i++) {
@@ -49,13 +54,16 @@ bool LocalHandles::Contains(Address* location) {
 Address* LocalHandles::AddBlock() {
   DCHECK_EQ(scope_.next, scope_.limit);
   Address* block = NewArray<Address>(kHandleBlockSize);
+#ifdef ENABLE_HANDLE_ZAPPING
+  ZapRange(block, block + kHandleBlockSize);
+#endif
   blocks_.push_back(block);
   scope_.next = block;
   scope_.limit = block + kHandleBlockSize;
   return block;
 }
 
-void LocalHandles::RemoveBlocks() {
+void LocalHandles::RemoveUnusedBlocks() {
   while (!blocks_.empty()) {
     Address* block_start = blocks_.back();
     Address* block_limit = block_start + kHandleBlockSize;
@@ -66,11 +74,19 @@ void LocalHandles::RemoveBlocks() {
 
     blocks_.pop_back();
 
-    // TODO(dinfuehr): Zap handles in block
+#ifdef ENABLE_HANDLE_ZAPPING
+    ZapRange(block_start, block_limit);
+#endif
 
     DeleteArray(block_start);
   }
 }
 
+#ifdef ENABLE_HANDLE_ZAPPING
+void LocalHandles::ZapRange(Address* start, Address* end) {
+  HandleScope::ZapRange(start, end);
+}
+#endif
+
 }  // namespace internal
 }  // namespace v8

src/handles/local-handles.h

@@ -19,6 +19,7 @@ class RootVisitor;
 class LocalHandles {
  public:
   LocalHandles();
+  ~LocalHandles();
 
   void Iterate(RootVisitor* visitor);
 
@@ -31,7 +32,11 @@ class LocalHandles {
   std::vector<Address*> blocks_;
 
   V8_EXPORT_PRIVATE Address* AddBlock();
-  V8_EXPORT_PRIVATE void RemoveBlocks();
+  V8_EXPORT_PRIVATE void RemoveUnusedBlocks();
+
+#ifdef ENABLE_HANDLE_ZAPPING
+  V8_EXPORT_PRIVATE static void ZapRange(Address* start, Address* end);
+#endif
 
   friend class LocalHandleScope;
 };

src/handles/persistent-handles.cc

@@ -26,6 +26,9 @@ PersistentHandles::~PersistentHandles() {
   isolate_->persistent_handles_list()->Remove(this);
 
   for (Address* block_start : blocks_) {
+#if ENABLE_HANDLE_ZAPPING
+    HandleScope::ZapRange(block_start, block_start + block_size_);
+#endif
     DeleteArray(block_start);
   }
 }

src/handles/persistent-handles.h

@@ -66,7 +66,7 @@ class PersistentHandles {
 
   Isolate* isolate_;
   std::vector<Address*> blocks_;
-  size_t block_size_;
+  const size_t block_size_;
 
   Address* block_next_;
   Address* block_limit_;

test/cctest/test-local-handles.cc

@@ -8,8 +8,10 @@
 #include "src/base/platform/condition-variable.h"
 #include "src/base/platform/mutex.h"
 #include "src/base/platform/semaphore.h"
+#include "src/common/globals.h"
 #include "src/handles/handles-inl.h"
 #include "src/handles/local-handles-inl.h"
+#include "src/handles/local-handles.h"
 #include "src/heap/heap.h"
 #include "src/heap/local-heap.h"
 #include "src/heap/safepoint.h"
@@ -94,6 +96,17 @@ TEST(CreateLocalHandles) {
   thread->Join();
 }
 
+TEST(CreateLocalHandlesWithoutLocalHandleScope) {
+  CcTest::InitializeVM();
+  FLAG_local_heaps = true;
+  Isolate* isolate = CcTest::i_isolate();
+
+  {
+    LocalHeap local_heap(isolate->heap());
+    handle(Smi::FromInt(17), &local_heap);
+  }
+}
+
 TEST(DereferenceLocalHandle) {
   CcTest::InitializeVM();
   FLAG_local_heaps = true;