[builtins] Improve performance of array.prototype.filter and map

src/code-stub-assembler.h

Index: src/code-stub-assembler.h
diff --git a/src/code-stub-assembler.h b/src/code-stub-assembler.h
index 3e20e6fb32042c729a9f4b3285cfe9fc92183f9f..2b2c5cdc1b7dfae71279a5ccddc65da441460a75 100644
--- a/src/code-stub-assembler.h
+++ b/src/code-stub-assembler.h
@@ -501,9 +501,23 @@ class V8_EXPORT_PRIVATE CodeStubAssembler : public compiler::CodeAssembler {
       Node* object, Node* index, Node* value,
       ParameterMode parameter_mode = INTPTR_PARAMETERS);
 
-  Node* BuildAppendJSArray(ElementsKind kind, Node* context, Node* array,
+  // EnsureArrayPushable verifies that receiver is:
+  //   1. Is not a prototype.
+  //   2. Is not a dictionary.
+  //   3. Has a writeable length property.
+  // It returns ElementsKind as a node for further division into cases.
+  Node* EnsureArrayPushable(Node* receiver, Label* bailout);
+
+  void TryStoreArrayElement(ElementsKind kind, ParameterMode mode,
+                            Label* bailout, Node* elements, Node* index,
+                            Node* value);
+  // Consumes args into the array, and returns tagged new length.
+  Node* BuildAppendJSArray(ElementsKind kind, Node* array,
                            CodeStubArguments& args, Variable& arg_index,
                            Label* bailout);
+  // Pushes value onto the end of array.
+  void BuildAppendJSArray(ElementsKind kind, Node* array, Node* value,
+                          Label* bailout);
 
   void StoreFieldsNoWriteBarrier(Node* start_address, Node* end_address,
                                  Node* value);
@@ -663,6 +677,15 @@ class V8_EXPORT_PRIVATE CodeStubAssembler : public compiler::CodeAssembler {
                              Node* capacity, Node* new_capacity,
                              ParameterMode mode, Label* bailout);
 
+  // Given a need to grow by |growth|, allocate an appropriate new capacity
+  // and return a new elements FixedArray object. Label |bailout| is
+  // followed for allocation failure. Label |fits| is followed if current

[danno, 2017/04/24 12:12:11]

nit: There is no label |fits|?

[mvstanton, 2017/04/24 12:21:16]

Ah! Outdated comment - I fixed the wording. Thanks!

+  // capacity is sufficient.
+  void PossiblyGrowElementsCapacity(ParameterMode mode, ElementsKind kind,
+                                    Node* array, Node* length,
+                                    Variable* var_elements, Node* growth,
+                                    Label* bailout);
+
   // Allocation site manipulation
   void InitializeAllocationMemento(Node* base_allocation,
                                    int base_allocation_size,
@@ -750,6 +773,8 @@ class V8_EXPORT_PRIVATE CodeStubAssembler : public compiler::CodeAssembler {
   // ElementsKind helpers:
   Node* IsFastElementsKind(Node* elements_kind);
   Node* IsHoleyFastElementsKind(Node* elements_kind);
+  Node* IsElementsKindGreaterThan(Node* target_kind,
+                                  ElementsKind reference_kind);
 
   // String helpers.
   // Load a character from a String (might flatten a ConsString).