Store transitioned JSArray maps in global context

src/x64/macro-assembler-x64.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 4015 matching lines @@
   // chain (i.e., the static scope chain and runtime context chain do
   // not agree).  A variable occurring in such a scope should have
   // slot type LOOKUP and not CONTEXT.
   if (emit_debug_code()) {
     CompareRoot(FieldOperand(dst, HeapObject::kMapOffset),
                 Heap::kWithContextMapRootIndex);
     Check(not_equal, "Variable resolved to with context.");
   }
 }
 
+
+void MacroAssembler::LoadGlobalInitialConstructedArrayMap(
+    Register function_in, Register scratch, Register map_out) {
+  ASSERT(!function_in.is(map_out));
+  Label done;
+  movq(map_out, FieldOperand(function_in,
+                             JSFunction::kPrototypeOrInitialMapOffset));
+  if (!FLAG_smi_only_arrays) {
+    // Load the global or builtins object from the current context.
+    movq(scratch, Operand(rsi, Context::SlotOffset(Context::GLOBAL_INDEX)));
+    movq(scratch, FieldOperand(scratch, GlobalObject::kGlobalContextOffset));
+
+    // Check that the function's map is same as the cached map.
+    cmpq(map_out,
+         Operand(scratch,
+                 Context::SlotOffset(Context::SMI_JS_ARRAY_MAP_INDEX)));
+    j(not_equal, &done);
+
+    // Use the cached transitioned map.
+    movq(map_out,
+         Operand(scratch,
+                 Context::SlotOffset(Context::OBJECT_JS_ARRAY_MAP_INDEX)));
+  }
+  bind(&done);
+}
+
 #ifdef _WIN64
 static const int kRegisterPassedArguments = 4;
 #else
 static const int kRegisterPassedArguments = 6;
 #endif
 
 void MacroAssembler::LoadGlobalFunction(int index, Register function) {
   // Load the global or builtins object from the current context.
   movq(function, Operand(rsi, Context::SlotOffset(Context::GLOBAL_INDEX)));
   // Load the global context from the global or builtins object.
@@ skipping 292 matching lines @@
 
   and_(bitmap_scratch, Immediate(~Page::kPageAlignmentMask));
   addl(Operand(bitmap_scratch, MemoryChunk::kLiveBytesOffset), length);
 
   bind(&done);
 }
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64