[PATCH] XCore target add __LITTLE_ENDIAN__ defined macro

[robert lytton]

  Hi Richard,

  The lnt test-suite's file tools/TargetConfig.mk.in uses the macro to steer the testing viz:

    #ifdef __LITTLE_ENDIAN__
    ENDIAN := little
    #else
    ENDIAN := big
    #endif

  All targets get the define __BYTE_ORDER__ (added in GCC 4.6) viz:
    #define __BYTE_ORDER__ __ORDER_LITTLE_ENDIAN__

  However other targets do define additional endianess:

    // AARCH64-NETBSD:#define __LITTLE_ENDIAN__ 1
    // ARM:#define __LITTLE_ENDIAN__ 1
    // ARMEABISOFTFP:#define __LITTLE_ENDIAN__ 1
    // ARMEABIHARDFP:#define __LITTLE_ENDIAN__ 1
    // I386:#define __LITTLE_ENDIAN__ 1
    // I386-LINUX:#define __LITTLE_ENDIAN__ 1
    // I386-NETBSD:#define __LITTLE_ENDIAN__ 1
    // PPC603E:#define _BIG_ENDIAN 1
    // PPC603E:#define __BIG_ENDIAN__ 1
    // PPC64:#define _BIG_ENDIAN 1
    // PPC64:#define __BIG_ENDIAN__ 1
    // PPC64LE:#define _LITTLE_ENDIAN 1
    // PPC64LE:#define __LITTLE_ENDIAN__ 1
    // PPC64-LINUX:#define _BIG_ENDIAN 1
    // PPC64-LINUX:#define __BIG_ENDIAN__ 1
    // PPC:#define _BIG_ENDIAN 1
    // PPC:#define __BIG_ENDIAN__ 1
    // PPC-LINUX:#define _BIG_ENDIAN 1
    // PPC-LINUX:#define __BIG_ENDIAN__ 1
    // PPC-DARWIN:#define _BIG_ENDIAN 1
    // PPC-DARWIN:#define __BIG_ENDIAN__ 1
    // X86_64:#define __LITTLE_ENDIAN__ 1
    // X86_64-LINUX:#define __LITTLE_ENDIAN__ 1
    // X86_64-NETBSD:#define __LITTLE_ENDIAN__ 1

  If we do not wish to define __LITTLE_ENDIAN__ we could either alter tools/TargetConfig.mk.in to use:
    #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
  or we could explicitly add '__LITTLE_ENDIAN__' to the $(TARGET_FLAGS) we pass into lnt - which is the simplest option!

  Robert

http://llvm-reviews.chandlerc.com/D2760