MIPS: Store transitioned JSArray maps in global context

Port r10523 (79463).

BUG=
TEST=

Review URL: https://chromiumcodereview.appspot.com/9298011
Patch from Daniel Kalmar <kalmard@homejinni.com>.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@10537 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/mips/builtins-mips.cc

@@ -116,9 +116,7 @@ static void AllocateEmptyJSArray(MacroAssembler* masm,
                                  Label* gc_required) {
   const int initial_capacity = JSArray::kPreallocatedArrayElements;
   STATIC_ASSERT(initial_capacity >= 0);
-  // Load the initial map from the array function.
-  __ lw(scratch1, FieldMemOperand(array_function,
-                                  JSFunction::kPrototypeOrInitialMapOffset));
+  __ LoadGlobalInitialConstructedArrayMap(array_function, scratch2, scratch1);
 
   // Allocate the JSArray object together with space for a fixed array with the
   // requested elements.
@@ -214,9 +212,8 @@ static void AllocateJSArray(MacroAssembler* masm,
                             bool fill_with_hole,
                             Label* gc_required) {
   // Load the initial map from the array function.
-  __ lw(elements_array_storage,
-         FieldMemOperand(array_function,
-                         JSFunction::kPrototypeOrInitialMapOffset));
+  __ LoadGlobalInitialConstructedArrayMap(array_function, scratch2,
+                                          elements_array_storage);
 
   if (FLAG_debug_code) {  // Assert that array size is not zero.
     __ Assert(

src/mips/macro-assembler-mips.cc

@@ -4279,6 +4279,31 @@ void MacroAssembler::LoadContext(Register dst, int context_chain_length) {
 }
 
 
+void MacroAssembler::LoadGlobalInitialConstructedArrayMap(
+    Register function_in, Register scratch, Register map_out) {
+  ASSERT(!function_in.is(map_out));
+  Label done;
+  lw(map_out, FieldMemOperand(function_in,
+                              JSFunction::kPrototypeOrInitialMapOffset));
+  if (!FLAG_smi_only_arrays) {
+    // Load the global or builtins object from the current context.
+    lw(scratch, MemOperand(cp, Context::SlotOffset(Context::GLOBAL_INDEX)));
+    lw(scratch, FieldMemOperand(scratch, GlobalObject::kGlobalContextOffset));
+
+    // Check that the function's map is same as the cached map.
+    lw(at, MemOperand(
+       scratch, Context::SlotOffset(Context::SMI_JS_ARRAY_MAP_INDEX)));
+    Branch(&done, ne, map_out, Operand(at));
+
+    // Use the cached transitioned map.
+    lw(map_out,
+       MemOperand(scratch,
+                  Context::SlotOffset(Context::OBJECT_JS_ARRAY_MAP_INDEX)));
+  }
+  bind(&done);
+}
+
+
 void MacroAssembler::LoadGlobalFunction(int index, Register function) {
   // Load the global or builtins object from the current context.
   lw(function, MemOperand(cp, Context::SlotOffset(Context::GLOBAL_INDEX)));

src/mips/macro-assembler-mips.h

@@ -772,6 +772,11 @@ class MacroAssembler: public Assembler {
 
   void LoadContext(Register dst, int context_chain_length);
 
+  // Load the initial map for new Arrays of a given type.
+  void LoadGlobalInitialConstructedArrayMap(Register function_in,
+                                            Register scratch,
+                                            Register map_out);
+
   void LoadGlobalFunction(int index, Register function);
 
   // Load the initial map from the global function. The registers