MIPS64: Add big-endian support for mips64.

src/mips64/constants-mips64.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef  V8_MIPS_CONSTANTS_H_
 #define  V8_MIPS_CONSTANTS_H_
 
 #include "src/base/logging.h"
 #include "src/base/macros.h"
 #include "src/globals.h"
@@ skipping 17 matching lines @@
 
 #ifdef _MIPS_ARCH_MIPS64R2
   static const ArchVariants kArchVariant = kMips64r2;
 #elif  _MIPS_ARCH_MIPS64R6
   static const ArchVariants kArchVariant = kMips64r6;
 #else
   static const ArchVariants kArchVariant = kMips64r2;
 #endif
 
 
+  enum Endianness { kLittle, kBig };
+
+#if defined(V8_TARGET_LITTLE_ENDIAN)
+  static const Endianness kArchEndian = kLittle;
+#elif defined(V8_TARGET_BIG_ENDIAN)
+  static const Endianness kArchEndian = kBig;
+#else
+#error Unknown endianness
+#endif
+
 // TODO(plind): consider deriving ABI from compiler flags or build system.
 
 // ABI-dependent definitions are made with #define in simulator-mips64.h,
 // so the ABI choice must be available to the pre-processor. However, in all
 // other cases, we should use the enum AbiVariants with normal if statements.
 
 #define MIPS_ABI_N64 1
 // #define MIPS_ABI_O32 1
 
 // The only supported Abi's are O32, and n64.
@@ skipping 1026 matching lines @@
 // TODO(plind): below should be based on kPointerSize
 // TODO(plind): find all usages and remove the needless instructions for n64.
 const int kCArgsSlotsSize = kCArgSlotCount * Instruction::kInstrSize * 2;
 
 const int kInvalidStackOffset = -1;
 const int kBranchReturnOffset = 2 * Instruction::kInstrSize;
 
 } }   // namespace v8::internal
 
 #endif    // #ifndef V8_MIPS_CONSTANTS_H_