gh-95855: Better platform triplet detection code

Misc/platform_triplet.c

@@ -0,0 +1,197 @@
+/* Detect platform triplet from builtin defines
+ * cc -E Misc/platform_triplet.c | grep -v '^#' | grep -v '^ *$' | grep -v '^typedef' | tr -d ' '
+ */
+#undef bfin
+#undef cris
+#undef fr30
+#undef linux
+#undef hppa
+#undef hpux
+#undef i386
+#undef mips
+#undef powerpc
+#undef sparc
+#undef unix
+#if defined(__ANDROID__)
+    # Android is not a multiarch system.
+#elif defined(__linux__)
+/*
+ * BEGIN of Linux block
+ */
+// detect libc (glibc, musl)
+# include <features.h>
+# if defined(__UCLIBC__)
+#  error "uclibc is not supported"
+# elif defined(__dietlibc__)
+#  error "dietlibc is not supported"
+# elif defined(__GLIBC__)
+#  define LIBC gnu
+#  define LIBC_X32 gnux32
+#  define LIBC_ARM_EABIHF gnueabihf
+#  define LIBC_ARM_EABI gnueabi
+#  define LIBC_PPC_SPE gnuspe
+#  if defined(_MIPS_SIM)
+#   if _MIPS_SIM == _ABIO32
+        define LIBC_MIPS_SIM gnu
+#   elif _MIPS_SIM == _ABIN32
+        define LIBC_MIPS_SIM gnuabin32
+#   elif _MIPS_SIM == _ABI64
+        define LIBC_MIPS_SIM gnuabi64
+#   endif
+#  endif /* defined(_MIPS_SIM) */
+# else
+/* heuristic to detect musl libc (based on config.guess).
+ * Adds "typedef __builtin_va_list va_list;" to output.
+ */
+#  include <stdarg.h>
+#  ifdef __DEFINED_va_list
+#   define LIBC musl
+// #   define LIBC_X32
+#   define LIBC_ARM_EABIHF musleabihf
+#   define LIBC_ARM_EABI musleabi
+//#   define LIBC_PPC_SPE
+#   define LIBC_MIPS_SIM musl
+#  else
+#   error "unknown libc"
+#  endif
+#endif
+
+# if defined(__x86_64__) && defined(__LP64__)
+        x86_64-linux-LIBC
+# elif defined(__x86_64__) && defined(__ILP32__) && defined(LIBC_X32)
+        x86_64-linux-LIBC_X32
+# elif defined(__i386__)
+        i386-linux-LIBC
+# elif defined(__aarch64__) && defined(__AARCH64EL__)
+#  if defined(__ILP32__)
+        aarch64_ilp32-linux-LIBC
+#  else
+        aarch64-linux-LIBC
+#  endif
+# elif defined(__aarch64__) && defined(__AARCH64EB__)
+#  if defined(__ILP32__)
+        aarch64_be_ilp32-linux-LIBC
+#  else
+        aarch64_be-linux-LIBC
+#  endif
+# elif defined(__alpha__)
+        alpha-linux-LIBC
+# elif defined(__ARM_EABI__) && defined(__ARM_PCS_VFP) && defined(LIBC_ARM_EABIHF)
+#  if defined(__ARMEL__)
+        arm-linux-LIBC_ARM_EABIHF
+#  else
+        armeb-linux-LIBC_ARM_EABIHF
+#  endif
+# elif defined(__ARM_EABI__) && !defined(__ARM_PCS_VFP) && defined(LIBC_ARM_EABI)
+#  if defined(__ARMEL__)
+        arm-linux-LIBC_ARM_EABI
+#  else
+        armeb-linux-LIBC_ARM_EABI
+#  endif
+# elif defined(__hppa__)
+        hppa-linux-LIBC
+# elif defined(__ia64__)
+        ia64-linux-LIBC
+# elif defined(__m68k__) && !defined(__mcoldfire__)
+        m68k-linux-LIBC
+# elif defined(__mips_hard_float) && defined(__mips_isa_rev) && (__mips_isa_rev >=6) && defined(_MIPSEL) && defined(LIBC_MIPS_SIM)
+#  if _MIPS_SIM == _ABIO32
+        mipsisa32r6el-linux-LIBC_MIPS_SIM
+#  elif (_MIPS_SIM == _ABIN32) || (_MIPS_SIM == _ABI64)
+        mipsisa64r6el-linux-LIBC_MIPS_SIM
+#  else
+#   error unknown platform triplet
+#  endif
+# elif defined(__mips_hard_float) && defined(__mips_isa_rev) && (__mips_isa_rev >=6) && defined(LIBC_MIPS_SIM)
+#  if _MIPS_SIM == _ABIO32
+        mipsisa32r6-linux-LIBC_MIPS_SIM
+#  elif (_MIPS_SIM == _ABIN32) || (_MIPS_SIM == _ABI64)
+        mipsisa64r6-linux-LIBC_MIPS_SIM
+#  else
+#   error unknown platform triplet
+#  endif
+# elif defined(__mips_hard_float) && defined(_MIPSEL) && defined(LIBC_MIPS_SIM)
+#  if _MIPS_SIM == _ABIO32
+        mipsel-linux-LIBC_MIPS_SIM
+#  elif (_MIPS_SIM == _ABIN32) || (_MIPS_SIM == _ABI64)
+        mips64el-linux-LIBC_MIPS_SIM
+#  else
+#   error unknown platform triplet
+#  endif
+# elif defined(__mips_hard_float) && defined(LIBC_MIPS_SIM)
+#  if _MIPS_SIM == _ABIO32
+        mips-linux-LIBC_MIPS_SIM
+#  elif (_MIPS_SIM == _ABIN32) || (_MIPS_SIM == _ABI64)
+        mips64-linux-LIBC_MIPS_SIM
+#  else
+#   error unknown platform triplet
+#  endif
+# elif defined(__or1k__)
+        or1k-linux-LIBC
+# elif defined(__powerpc__) && defined(__SPE__) && defined(LIBC_PPC_SPE)
+        powerpc-linux-LIBC_PPC_SPE
+# elif defined(__powerpc64__)
+#  if defined(__LITTLE_ENDIAN__)
+        powerpc64le-linux-LIBC
+#  else
+        powerpc64-linux-LIBC
+#  endif
+# elif defined(__powerpc__)
+        powerpc-linux-LIBC
+# elif defined(__s390x__)
+        s390x-linux-LIBC
+# elif defined(__s390__)
+        s390-linux-LIBC
+# elif defined(__sh__) && defined(__LITTLE_ENDIAN__)
+        sh4-linux-LIBC
+# elif defined(__sparc__) && defined(__arch64__)
+        sparc64-linux-LIBC
+# elif defined(__sparc__)
+        sparc-linux-LIBC
+# elif defined(__riscv)
+#  if __riscv_xlen == 32
+        riscv32-linux-LIBC
+#  elif __riscv_xlen == 64
+        riscv64-linux-LIBC
+#  else
+#   error unknown platform triplet
+#  endif
+# else
+#   error unknown platform triplet
+# endif
+/*
+ * END of Linux block
+ */
+#elif defined(__FreeBSD_kernel__)
+# if defined(__LP64__)
+        x86_64-kfreebsd-gnu
+# elif defined(__i386__)
+        i386-kfreebsd-gnu
+# else
+#   error unknown platform triplet
+# endif
+#elif defined(__gnu_hurd__)
+        i386-gnu
+#elif defined(__APPLE__)
+        darwin
+#elif defined(__VXWORKS__)
+        vxworks
+#elif defined(__EMSCRIPTEN__)
+#  if defined(__wasm32__)
+        wasm32-emscripten
+#  elif defined(__wasm64__)
+        wasm64-emscripten
+#  else
+#    error unknown Emscripten platform
+#  endif
+#elif defined(__wasi__)
+#  if defined(__wasm32__)
+        wasm32-wasi
+#  elif defined(__wasm64__)
+        wasm64-wasi
+#  else
+#    error unknown WASI platform
+#  endif
+#else
+# error unknown platform triplet
+#endif