WIP SharedArrayBuffer implementation

src/runtime/runtime-typedarray.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/v8.h"
 
 #include "src/arguments.h"
 #include "src/runtime/runtime.h"
 #include "src/runtime/runtime-utils.h"
 
 
 namespace v8 {
 namespace internal {
 
 void Runtime::FreeArrayBuffer(Isolate* isolate,
                               JSArrayBuffer* phantom_array_buffer) {
   if (phantom_array_buffer->should_be_freed()) {
     DCHECK(phantom_array_buffer->is_external());
     free(phantom_array_buffer->backing_store());
   }
   if (phantom_array_buffer->is_external()) return;
 
   size_t allocated_length =
       NumberToSize(isolate, phantom_array_buffer->byte_length());
 
   reinterpret_cast<v8::Isolate*>(isolate)
       ->AdjustAmountOfExternalAllocatedMemory(
           -static_cast<int64_t>(allocated_length));
-  CHECK(V8::ArrayBufferAllocator() != NULL);
-  V8::ArrayBufferAllocator()->Free(phantom_array_buffer->backing_store(),
-                                   allocated_length);
+  if (phantom_array_buffer->is_shared()) {
+    CHECK(V8::SharedArrayBufferAllocator() != NULL);
+    V8::SharedArrayBufferAllocator()->Free(
+        phantom_array_buffer->backing_store(), allocated_length);
+  } else {
+    CHECK(V8::ArrayBufferAllocator() != NULL);
+    V8::ArrayBufferAllocator()->Free(phantom_array_buffer->backing_store(),
+                                     allocated_length);
+  }
 }
 
 
 void Runtime::SetupArrayBuffer(Isolate* isolate,
                                Handle<JSArrayBuffer> array_buffer,
                                bool is_external, void* data,
-                               size_t allocated_length) {
+                               size_t allocated_length, bool is_shared) {
   DCHECK(array_buffer->GetInternalFieldCount() ==
          v8::ArrayBuffer::kInternalFieldCount);
   for (int i = 0; i < v8::ArrayBuffer::kInternalFieldCount; i++) {
     array_buffer->SetInternalField(i, Smi::FromInt(0));
   }
   array_buffer->set_backing_store(data);
   array_buffer->set_flag(Smi::FromInt(0));
   array_buffer->set_is_external(is_external);
   array_buffer->set_is_neuterable(true);
+  array_buffer->set_is_shared(is_shared);
 
   Handle<Object> byte_length =
       isolate->factory()->NewNumberFromSize(allocated_length);
   CHECK(byte_length->IsSmi() || byte_length->IsHeapNumber());
   array_buffer->set_byte_length(*byte_length);
 
   array_buffer->set_weak_next(isolate->heap()->array_buffers_list());
   isolate->heap()->set_array_buffers_list(*array_buffer);
   array_buffer->set_weak_first_view(isolate->heap()->undefined_value());
 }
 
 
 bool Runtime::SetupArrayBufferAllocatingData(Isolate* isolate,
                                              Handle<JSArrayBuffer> array_buffer,
                                              size_t allocated_length,
-                                             bool initialize) {
+                                             bool initialize, bool is_shared) {
   void* data;
-  CHECK(V8::ArrayBufferAllocator() != NULL);
+  CHECK(is_shared ? V8::SharedArrayBufferAllocator() != NULL
+                  : V8::ArrayBufferAllocator() != NULL);
   // Prevent creating array buffers when serializing.
   DCHECK(!isolate->serializer_enabled());
   if (allocated_length != 0) {
-    if (initialize) {
-      data = V8::ArrayBufferAllocator()->Allocate(allocated_length);
+    if (is_shared) {
+      if (initialize) {
+        data = V8::SharedArrayBufferAllocator()->Allocate(allocated_length);
+      } else {
+        data = V8::SharedArrayBufferAllocator()->AllocateUninitialized(
+            allocated_length);
+      }
     } else {
-      data =
-          V8::ArrayBufferAllocator()->AllocateUninitialized(allocated_length);
+      if (initialize) {
+        data = V8::ArrayBufferAllocator()->Allocate(allocated_length);
+      } else {
+        data =
+            V8::ArrayBufferAllocator()->AllocateUninitialized(allocated_length);
+      }
     }
     if (data == NULL) return false;
   } else {
     data = NULL;
   }
 
-  SetupArrayBuffer(isolate, array_buffer, false, data, allocated_length);
+  SetupArrayBuffer(isolate, array_buffer, false, data, allocated_length,
+                   is_shared);
 
   reinterpret_cast<v8::Isolate*>(isolate)
       ->AdjustAmountOfExternalAllocatedMemory(allocated_length);
 
   return true;
 }
 
 
 void Runtime::NeuterArrayBuffer(Handle<JSArrayBuffer> array_buffer) {
   Isolate* isolate = array_buffer->GetIsolate();
@@ skipping 28 matching lines @@
       }
     }
     view_obj = handle(view->weak_next(), isolate);
   }
   array_buffer->Neuter();
 }
 
 
 RUNTIME_FUNCTION(Runtime_ArrayBufferInitialize) {
   HandleScope scope(isolate);
-  DCHECK(args.length() == 2);
+  DCHECK(args.length() == 3);
   CONVERT_ARG_HANDLE_CHECKED(JSArrayBuffer, holder, 0);
   CONVERT_NUMBER_ARG_HANDLE_CHECKED(byteLength, 1);
+  CONVERT_BOOLEAN_ARG_CHECKED(isShared, 2);
   if (!holder->byte_length()->IsUndefined()) {
     // ArrayBuffer is already initialized; probably a fuzz test.
     return *holder;
   }
   size_t allocated_length = 0;
   if (!TryNumberToSize(isolate, *byteLength, &allocated_length)) {
     THROW_NEW_ERROR_RETURN_FAILURE(
         isolate, NewRangeError("invalid_array_buffer_length",
                                HandleVector<Object>(NULL, 0)));
   }
-  if (!Runtime::SetupArrayBufferAllocatingData(isolate, holder,
-                                               allocated_length)) {
+  if (!Runtime::SetupArrayBufferAllocatingData(
+          isolate, holder, allocated_length, true, isShared)) {
     THROW_NEW_ERROR_RETURN_FAILURE(
         isolate, NewRangeError("invalid_array_buffer_length",
                                HandleVector<Object>(NULL, 0)));
   }
   return *holder;
 }
 
 
 RUNTIME_FUNCTION(Runtime_ArrayBufferGetByteLength) {
   SealHandleScope shs(isolate);
   DCHECK(args.length() == 1);
   CONVERT_ARG_CHECKED(JSArrayBuffer, holder, 0);
   return holder->byte_length();
 }
 
 
+RUNTIME_FUNCTION(Runtime_ArrayBufferIsShared) {
+  SealHandleScope shs(isolate);
+  DCHECK(args.length() == 1);
+  CONVERT_ARG_CHECKED(JSArrayBuffer, holder, 0);
+  return isolate->heap()->ToBoolean(holder->is_shared());
+}
+
+
 RUNTIME_FUNCTION(Runtime_ArrayBufferSliceImpl) {
   HandleScope scope(isolate);
   DCHECK(args.length() == 3);
   CONVERT_ARG_HANDLE_CHECKED(JSArrayBuffer, source, 0);
   CONVERT_ARG_HANDLE_CHECKED(JSArrayBuffer, target, 1);
   CONVERT_NUMBER_ARG_HANDLE_CHECKED(first, 2);
   RUNTIME_ASSERT(!source.is_identical_to(target));
   size_t start = 0;
   RUNTIME_ASSERT(TryNumberToSize(isolate, *first, &start));
   size_t target_length = NumberToSize(isolate, target->byte_length());
@@ skipping 19 matching lines @@
 
 
 RUNTIME_FUNCTION(Runtime_ArrayBufferNeuter) {
   HandleScope scope(isolate);
   DCHECK(args.length() == 1);
   CONVERT_ARG_HANDLE_CHECKED(JSArrayBuffer, array_buffer, 0);
   if (array_buffer->backing_store() == NULL) {
     CHECK(Smi::FromInt(0) == array_buffer->byte_length());
     return isolate->heap()->undefined_value();
   }
+  // Shared array buffers should never be neutered.
+  DCHECK(!array_buffer->is_shared());
   DCHECK(!array_buffer->is_external());
   void* backing_store = array_buffer->backing_store();
   size_t byte_length = NumberToSize(isolate, array_buffer->byte_length());
   array_buffer->set_is_external(true);
   Runtime::NeuterArrayBuffer(array_buffer);
   V8::ArrayBufferAllocator()->Free(backing_store, byte_length);
   return isolate->heap()->undefined_value();
 }
 
 
@@ skipping 14 matching lines @@
 #undef ARRAY_ID_CASE
 
     default:
       UNREACHABLE();
   }
 }
 
 
 RUNTIME_FUNCTION(Runtime_TypedArrayInitialize) {
   HandleScope scope(isolate);
-  DCHECK(args.length() == 5);
+  DCHECK(args.length() == 6);
   CONVERT_ARG_HANDLE_CHECKED(JSTypedArray, holder, 0);
   CONVERT_SMI_ARG_CHECKED(arrayId, 1);
   CONVERT_ARG_HANDLE_CHECKED(Object, maybe_buffer, 2);
   CONVERT_NUMBER_ARG_HANDLE_CHECKED(byte_offset_object, 3);
   CONVERT_NUMBER_ARG_HANDLE_CHECKED(byte_length_object, 4);
+  CONVERT_BOOLEAN_ARG_CHECKED(isShared, 5);
 
   RUNTIME_ASSERT(arrayId >= Runtime::ARRAY_ID_FIRST &&
                  arrayId <= Runtime::ARRAY_ID_LAST);
 
   ExternalArrayType array_type = kExternalInt8Array;  // Bogus initialization.
   size_t element_size = 1;                            // Bogus initialization.
   ElementsKind external_elements_kind =
       EXTERNAL_INT8_ELEMENTS;                        // Bogus initialization.
   ElementsKind fixed_elements_kind = INT8_ELEMENTS;  // Bogus initialization.
   Runtime::ArrayIdToTypeAndSize(arrayId, &array_type, &external_elements_kind,
                                 &fixed_elements_kind, &element_size);
   RUNTIME_ASSERT(holder->map()->elements_kind() == fixed_elements_kind);
 
   size_t byte_offset = 0;
   size_t byte_length = 0;
   RUNTIME_ASSERT(TryNumberToSize(isolate, *byte_offset_object, &byte_offset));
   RUNTIME_ASSERT(TryNumberToSize(isolate, *byte_length_object, &byte_length));
 
   if (maybe_buffer->IsJSArrayBuffer()) {
     Handle<JSArrayBuffer> buffer = Handle<JSArrayBuffer>::cast(maybe_buffer);
     size_t array_buffer_byte_length =
         NumberToSize(isolate, buffer->byte_length());
     RUNTIME_ASSERT(byte_offset <= array_buffer_byte_length);
     RUNTIME_ASSERT(array_buffer_byte_length - byte_offset >= byte_length);
+    RUNTIME_ASSERT(isShared == buffer->is_shared());
   } else {
     RUNTIME_ASSERT(maybe_buffer->IsNull());
   }
 
   RUNTIME_ASSERT(byte_length % element_size == 0);
   size_t length = byte_length / element_size;
 
   if (length > static_cast<unsigned>(Smi::kMaxValue)) {
     THROW_NEW_ERROR_RETURN_FAILURE(
         isolate, NewRangeError("invalid_typed_array_length",
                                HandleVector<Object>(NULL, 0)));
   }
 
   // All checks are done, now we can modify objects.
 
   DCHECK(holder->GetInternalFieldCount() ==
          v8::ArrayBufferView::kInternalFieldCount);
   for (int i = 0; i < v8::ArrayBufferView::kInternalFieldCount; i++) {
     holder->SetInternalField(i, Smi::FromInt(0));
   }
   Handle<Object> length_obj = isolate->factory()->NewNumberFromSize(length);
   holder->set_length(*length_obj);
   holder->set_byte_offset(*byte_offset_object);
   holder->set_byte_length(*byte_length_object);
+  holder->set_is_shared(isShared);
 
   Heap* heap = isolate->heap();
   if (!maybe_buffer->IsNull()) {
     Handle<JSArrayBuffer> buffer = Handle<JSArrayBuffer>::cast(maybe_buffer);
     holder->set_buffer(*buffer);
 
     if (heap->InNewSpace(*holder)) {
       holder->set_weak_next(heap->new_array_buffer_views_list());
       heap->set_new_array_buffer_views_list(*holder);
     } else {
@@ skipping 504 matching lines @@
 DATA_VIEW_SETTER(Uint16, uint16_t)
 DATA_VIEW_SETTER(Int16, int16_t)
 DATA_VIEW_SETTER(Uint32, uint32_t)
 DATA_VIEW_SETTER(Int32, int32_t)
 DATA_VIEW_SETTER(Float32, float)
 DATA_VIEW_SETTER(Float64, double)
 
 #undef DATA_VIEW_SETTER
 }
 }  // namespace v8::internal