MIPS: Added support for Loongson architectures.

src/mips/constants-mips.h

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 21 matching lines @@
 #ifdef DEBUG
 #define UNIMPLEMENTED_MIPS()                                                  \
   v8::internal::PrintF("%s, \tline %d: \tfunction %s not implemented. \n",    \
                        __FILE__, __LINE__, __func__)
 #else
 #define UNIMPLEMENTED_MIPS()
 #endif
 
 #define UNSUPPORTED_MIPS() v8::internal::PrintF("Unsupported instruction.\n")
 
+enum ArchVariants {
+  kMips32r2,
+  kMips32r1,
+  kLoongson
+};
 
 #ifdef _MIPS_ARCH_MIPS32R2
-  #define mips32r2 1
+  static const ArchVariants kArchVariant = kMips32r2;
+#elif _MIPS_ARCH_LOONGSON
+// The loongson flag refers to the LOONGSON architectures based on MIPS-III,
+// which predates (and is a subset of) the mips32r2 and r1 architectures.
+  static const ArchVariants kArchVariant = kLoongson;
 #else
-  #define mips32r2 0
+  static const ArchVariants kArchVariant = kMips32r1;
 #endif
 
 
 #if(defined(__mips_hard_float) && __mips_hard_float != 0)
 // Use floating-point coprocessor instructions. This flag is raised when
 // -mhard-float is passed to the compiler.
 const bool IsMipsSoftFloatABI = false;
 #elif(defined(__mips_soft_float) && __mips_soft_float != 0)
 // Not using floating-point coprocessor instructions. This flag is raised when
 // -msoft-float is passed to the compiler.
@@ skipping 723 matching lines @@
 const int kBranchReturnOffset = 2 * Instruction::kInstrSize;
 
 const int kDoubleAlignmentBits = 3;
 const int kDoubleAlignment = (1 << kDoubleAlignmentBits);
 const int kDoubleAlignmentMask = kDoubleAlignment - 1;
 
 
 } }   // namespace v8::internal
 
 #endif    // #ifndef V8_MIPS_CONSTANTS_H_