1 files changed, 83 insertions, 0 deletions
diff --git a/deps/v8/src/builtins/constants-table-builder.cc b/deps/v8/src/builtins/constants-table-builder.cc
new file mode 100644
index 0000000000..a4117bd5a2
--- /dev/null
+++ b/deps/v8/src/builtins/constants-table-builder.cc
@@ -0,0 +1,83 @@
+// Copyright 2018 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/builtins/constants-table-builder.h"
+
+#include "src/heap/heap-inl.h"
+
+namespace v8 {
+namespace internal {
+
+BuiltinsConstantsTableBuilder::BuiltinsConstantsTableBuilder(Isolate* isolate)
+    : isolate_(isolate), map_(isolate->heap()) {
+  // Ensure this is only called once per Isolate.
+  DCHECK_EQ(isolate_->heap()->empty_fixed_array(),
+            isolate_->heap()->builtins_constants_table());
+
+  // And that the initial value of the builtins constants table can be treated
+  // as a constant, which means that codegen will load it using the root
+  // register.
+  DCHECK(isolate_->heap()->RootCanBeTreatedAsConstant(
+      Heap::kEmptyFixedArrayRootIndex));
+}
+
+uint32_t BuiltinsConstantsTableBuilder::AddObject(Handle<Object> object) {
+#ifdef DEBUG
+  // Roots must not be inserted into the constants table as they are already
+  // accessibly from the root list.
+  Heap::RootListIndex root_list_index;
+  DCHECK(!isolate_->heap()->IsRootHandle(object, &root_list_index));
+
+  // Not yet finalized.
+  DCHECK_EQ(isolate_->heap()->empty_fixed_array(),
+            isolate_->heap()->builtins_constants_table());
+#endif
+
+  uint32_t* maybe_key = map_.Find(object);
+  if (maybe_key == nullptr) {
+    uint32_t index = map_.size();
+    map_.Set(object, index);
+    return index;
+  } else {
+    return *maybe_key;
+  }
+}
+
+void BuiltinsConstantsTableBuilder::Finalize() {
+  HandleScope handle_scope(isolate_);
+
+  DCHECK_EQ(isolate_->heap()->empty_fixed_array(),
+            isolate_->heap()->builtins_constants_table());
+
+  DCHECK_LT(0, map_.size());
+  Handle<FixedArray> table =
+      isolate_->factory()->NewFixedArray(map_.size(), TENURED);
+
+  Builtins* builtins = isolate_->builtins();
+  ConstantsMap::IteratableScope it_scope(&map_);
+  for (auto it = it_scope.begin(); it != it_scope.end(); ++it) {
+    uint32_t index = *it.entry();
+    Object* value = it.key();
+    if (value->IsCode() && Code::cast(value)->kind() == Code::BUILTIN) {
+      // Replace placeholder code objects with the real builtin.
+      // See also: SetupIsolateDelegate::PopulateWithPlaceholders.
+      // TODO(jgruber): Deduplicate placeholders and their corresponding
+      // builtin.
+      value = builtins->builtin(Code::cast(value)->builtin_index());
+    }
+    table->set(index, value);
+  }
+
+#ifdef DEBUG
+  for (int i = 0; i < map_.size(); i++) {
+    DCHECK(table->get(i)->IsHeapObject());
+    DCHECK_NE(isolate_->heap()->undefined_value(), table->get(i));
+  }
+#endif
+
+  isolate_->heap()->SetBuiltinsConstantsTable(*table);
+}
+
+}  // namespace internal
+}  // namespace v8