Create per-descriptor-index LoadApiGetterStub

src/code-stubs.cc

Index: src/code-stubs.cc
diff --git a/src/code-stubs.cc b/src/code-stubs.cc
index 27712ce73f27be1d69ad8550cfd79a0660c52e70..a90b8853925dab269502a6cf2bfae3f514b1cd5e 100644
--- a/src/code-stubs.cc
+++ b/src/code-stubs.cc
@@ -3243,6 +3243,24 @@ void GenerateStringEqual(compiler::CodeStubAssembler* assembler,
 
 }  // namespace
 
+void LoadApiGetterStub::GenerateAssembly(
+    compiler::CodeStubAssembler* assembler) const {
+  typedef compiler::Node Node;
+  Node* context = assembler->Parameter(3);
+  Node* receiver = assembler->Parameter(0);
+  // For now we only support receiver_is_holder.
+  DCHECK(receiver_is_holder());
+  Node* holder = receiver;
+  Node* map = assembler->LoadMap(receiver);
+  Node* descriptors = assembler->LoadMapDescriptors(map);
+  Node* offset =
+      assembler->Int32Constant(DescriptorArray::ToValueIndex(index()));
+  Node* callback =
+      assembler->LoadFixedArrayElementInt32Index(descriptors, offset);
+  assembler->TailCallStub(CodeFactory::ApiGetter(isolate()), context, receiver,
+                          holder, callback);
+}
+
 void LessThanStub::GenerateAssembly(
     compiler::CodeStubAssembler* assembler) const {
   GenerateAbstractRelationalComparison(assembler, kLessThan);