[mips] Move all ByVal handling into CCState and tablegen-erated code. NFC.

Summary:
CCState already contains a byval implementation that is very similar to the
Mips custom code. This patch merges the custom code into the existing
common code and tablegen-erated code.

Reviewers: vmedic

Reviewed By: vmedic

Subscribers: rnk, llvm-commits

Differential Revision: http://reviews.llvm.org/D5977

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221059 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/Mips/MipsABIInfo.cpp

@@ -0,0 +1,29 @@
+//===---- MipsABIInfo.cpp - Information about MIPS ABI's ------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "MipsABIInfo.h"
+#include "MipsRegisterInfo.h"
+
+using namespace llvm;
+
+namespace {
+static const MCPhysReg O32IntRegs[4] = {Mips::A0, Mips::A1, Mips::A2, Mips::A3};
+
+static const MCPhysReg Mips64IntRegs[8] = {
+    Mips::A0_64, Mips::A1_64, Mips::A2_64, Mips::A3_64,
+    Mips::T0_64, Mips::T1_64, Mips::T2_64, Mips::T3_64};
+}
+
+const ArrayRef<MCPhysReg> MipsABIInfo::GetByValArgRegs() const {
+  if (IsO32())
+    return makeArrayRef(O32IntRegs);
+  if (IsN32() || IsN64())
+    return makeArrayRef(Mips64IntRegs);
+  llvm_unreachable("Unhandled ABI");
+}