[builtins] Start refactoring the Apply builtin.

src/mips/macro-assembler-mips.cc

Index: src/mips/macro-assembler-mips.cc
diff --git a/src/mips/macro-assembler-mips.cc b/src/mips/macro-assembler-mips.cc
index b38cb9b8c260689a57013d55c7640d10a8038269..451eab87f8a53b1afa988646fd9826bd192e65d7 100644
--- a/src/mips/macro-assembler-mips.cc
+++ b/src/mips/macro-assembler-mips.cc
@@ -5873,6 +5873,15 @@ void MacroAssembler::AssertSmi(Register object) {
   }
 }
 
+void MacroAssembler::AssertFixedArray(Register object) {
+  if (emit_debug_code()) {
+    STATIC_ASSERT(kSmiTag == 0);
+    SmiTst(object, t8);
+    Check(ne, kOperandIsASmiAndNotAFixedArray, t8, Operand(zero_reg));
+    GetObjectType(object, t8, t8);
+    Check(eq, kOperandIsNotAFixedArray, t8, Operand(FIXED_ARRAY_TYPE));
+  }
+}
 
 void MacroAssembler::AssertFunction(Register object) {
   if (emit_debug_code()) {