MIPS: Eliminate special keyed load string stub in favor of uniform handlers.

src/mips64/code-stubs-mips64.cc

Index: src/mips64/code-stubs-mips64.cc
diff --git a/src/mips64/code-stubs-mips64.cc b/src/mips64/code-stubs-mips64.cc
index 867c24df9c0889a611308316726e0078076df2b2..d570c5879ea6ae6988d313a1a5189eba3715a709 100644
--- a/src/mips64/code-stubs-mips64.cc
+++ b/src/mips64/code-stubs-mips64.cc
@@ -1405,6 +1405,34 @@ void JSEntryStub::Generate(MacroAssembler* masm) {
 }
 
 
+void LoadIndexedStringStub::Generate(MacroAssembler* masm) {
+  // Return address is in ra.
+  Label miss;
+
+  Register receiver = LoadDescriptor::ReceiverRegister();
+  Register index = LoadDescriptor::NameRegister();
+  Register scratch = a3;
+  Register result = v0;
+  DCHECK(!scratch.is(receiver) && !scratch.is(index));
+
+  StringCharAtGenerator char_at_generator(receiver, index, scratch, result,
+                                          &miss,  // When not a string.
+                                          &miss,  // When not a number.
+                                          &miss,  // When index out of range.
+                                          STRING_INDEX_IS_ARRAY_INDEX,
+                                          RECEIVER_IS_STRING);
+  char_at_generator.GenerateFast(masm);
+  __ Ret();
+
+  StubRuntimeCallHelper call_helper;
+  char_at_generator.GenerateSlow(masm, call_helper);
+
+  __ bind(&miss);
+  PropertyAccessCompiler::TailCallBuiltin(
+      masm, PropertyAccessCompiler::MissBuiltin(Code::KEYED_LOAD_IC));
+}
+
+
 // Uses registers a0 to a4.
 // Expected input (depending on whether args are in registers or on the stack):
 // * object: a0 or at sp + 1 * kPointerSize.