[Builtins] Provide a code-stub impl. of Array.prototype.map

src/builtins/builtins-array-gen.cc

Index: src/builtins/builtins-array-gen.cc
diff --git a/src/builtins/builtins-array-gen.cc b/src/builtins/builtins-array-gen.cc
index 41a75c49b0b660e7be0aa1be8ef9ba9cfc7d0c85..0027d91866e337bfa8ed2e311ed2365ab4532310 100644
--- a/src/builtins/builtins-array-gen.cc
+++ b/src/builtins/builtins-array-gen.cc
@@ -128,6 +128,11 @@ class ArrayBuiltinCodeStubAssembler : public CodeStubAssembler {
     return ArraySpeciesCreate(context(), o(), SmiConstant(0));
   }
 
+  Node* MapResultGenerator() {
+    // 7. Let A be ArraySpeciesCreate(O, 0).
+    return ArraySpeciesCreate(context(), o(), len_);
+  }
+

[danno, 2017/03/23 12:25:04]

Nit: Elsewhere we group the *Generator/*Filters together. Can you move this
after FilterProcessor?

[mvstanton, 2017/03/24 09:37:08]

Done.

   Node* FilterProcessor(Node* k_value, Node* k) {
     Node* callback_result = CallJS(CodeFactory::Call(isolate()), context(),
                                    callbackfn(), this_arg(), k_value, k, o());
@@ -147,6 +152,17 @@ class ArrayBuiltinCodeStubAssembler : public CodeStubAssembler {
     return a();
   }
 
+  Node* MapProcessor(Node* k_value, Node* k) {
+    Node* callback_result = CallJS(CodeFactory::Call(isolate()), context(),
+                                   callbackfn(), this_arg(), k_value, k, o());
+    // TODO(mvstanton): in some cases we have the ToString version of k,
+    // in the continuation.
+    Node* const p_k = ToString(context(), k);

[danno, 2017/03/23 12:25:04]

I wonder if you really need the ToString here, because CreateDataPropery should
be able to deal with all Numbers as property keys, and k is guaranteed to be a
Number, right? 

[mvstanton, 2017/03/24 09:37:08]

Done. This prompted some comment cleanup, to annotate what is happening
vis-a-vis the spec better.

+    CallRuntime(Runtime::kCreateDataProperty, context(), a(), p_k,
+                callback_result);
+    return a();
+  }
+
   void NullPostLoopAction() {}
 
  protected:
@@ -770,13 +786,50 @@ TF_BUILTIN(ArrayFilter, ArrayBuiltinCodeStubAssembler) {
                                 new_target);
 
   GenerateIteratingArrayBuiltinBody(
-      "Array.prototype.reduce",
+      "Array.prototype.filter",
       &ArrayBuiltinCodeStubAssembler::FilterResultGenerator,
       &ArrayBuiltinCodeStubAssembler::FilterProcessor,
       &ArrayBuiltinCodeStubAssembler::NullPostLoopAction,
       CodeFactory::ArrayFilterLoopContinuation(isolate()));
 }
 
+TF_BUILTIN(ArrayMapLoopContinuation, ArrayBuiltinCodeStubAssembler) {
+  Node* context = Parameter(Descriptor::kContext);
+  Node* receiver = Parameter(Descriptor::kReceiver);
+  Node* callbackfn = Parameter(Descriptor::kCallbackFn);
+  Node* this_arg = Parameter(Descriptor::kThisArg);
+  Node* array = Parameter(Descriptor::kArray);
+  Node* object = Parameter(Descriptor::kObject);
+  Node* initial_k = Parameter(Descriptor::kInitialK);
+  Node* len = Parameter(Descriptor::kLength);
+  Node* to = Parameter(Descriptor::kTo);
+
+  InitIteratingArrayBuiltinLoopContinuation(context, receiver, callbackfn,
+                                            this_arg, array, object, initial_k,
+                                            len, to);
+
+  GenerateIteratingArrayBuiltinLoopContinuation(
+      &ArrayBuiltinCodeStubAssembler::MapProcessor,
+      &ArrayBuiltinCodeStubAssembler::NullPostLoopAction);
+}
+
+TF_BUILTIN(ArrayMap, ArrayBuiltinCodeStubAssembler) {
+  Node* context = Parameter(Descriptor::kContext);
+  Node* receiver = Parameter(Descriptor::kReceiver);
+  Node* callbackfn = Parameter(Descriptor::kCallbackFn);
+  Node* this_arg = Parameter(Descriptor::kThisArg);
+  Node* new_target = Parameter(Descriptor::kNewTarget);
+
+  InitIteratingArrayBuiltinBody(context, receiver, callbackfn, this_arg,
+                                new_target);
+
+  GenerateIteratingArrayBuiltinBody(
+      "Array.prototype.map", &ArrayBuiltinCodeStubAssembler::MapResultGenerator,
+      &ArrayBuiltinCodeStubAssembler::MapProcessor,
+      &ArrayBuiltinCodeStubAssembler::NullPostLoopAction,
+      CodeFactory::ArrayMapLoopContinuation(isolate()));
+}
+
 TF_BUILTIN(ArrayIsArray, CodeStubAssembler) {
   Node* object = Parameter(Descriptor::kArg);
   Node* context = Parameter(Descriptor::kContext);