|  | GLIBC_PROVIDES dnl See aclocal.m4 in the top level source directory. | 
|  | # Local configure fragment for sysdeps/i386. | 
|  |  | 
|  | # We no longer support i386 since it lacks the atomic instructions | 
|  | # required to implement NPTL threading. | 
|  | if test "$config_machine" = i386; then | 
|  | AC_MSG_ERROR([ | 
|  | *** ERROR: Support for i386 is deprecated. | 
|  | *** Please use host i786, i686, i585 or i486. | 
|  | *** For example: /src/glibc/configure --host=i686-pc-linux-gnu ..."]) | 
|  | fi | 
|  |  | 
|  | # The GNU C Library can't be built for i386.  There are several reasons for | 
|  | # this restriction.  The primary reason is that i386 lacks the atomic | 
|  | # operations required to support the current NPTL implementation.  While it is | 
|  | # possible that such atomic operations could be emulated in the kernel to date | 
|  | # no such work has been done to enable this.  Even with NPTL disabled you still | 
|  | # have no atomic.h implementation.  Given the declining use of i386 we disable | 
|  | # support for building with `-march=i386' or `-mcpu=i386.' We don't explicitly | 
|  | # check for i386, instead we make sure the compiler has support for inlining | 
|  | # the builtin __sync_val_compare_and_swap. If it does then we should have no | 
|  | # problem building for i386. | 
|  | LIBC_COMPILER_BUILTIN_INLINED( | 
|  | [__sync_val_compare_and_swap], | 
|  | [int a, b, c; __sync_val_compare_and_swap (&a, b, c);], | 
|  | [-O0], | 
|  | [libc_cv_unsupported_i386=no], | 
|  | [AC_MSG_ERROR([ | 
|  | *** Building with -march=i386/-mcpu=i386 is not supported. | 
|  | *** Please use host i786, i686, i586, or i486. | 
|  | *** For example: /source/glibc/configure CFLAGS='-O2 -march=i686' ...])]) | 
|  |  | 
|  | dnl Check whether asm supports Intel MPX | 
|  | AC_CACHE_CHECK(for Intel MPX support, libc_cv_asm_mpx, [dnl | 
|  | cat > conftest.s <<\EOF | 
|  | bndmov %bnd0,(%esp) | 
|  | EOF | 
|  | if AC_TRY_COMMAND(${CC-cc} -c $ASFLAGS conftest.s 1>&AS_MESSAGE_LOG_FD); then | 
|  | libc_cv_asm_mpx=yes | 
|  | else | 
|  | libc_cv_asm_mpx=no | 
|  | fi | 
|  | rm -f conftest*]) | 
|  | if test $libc_cv_asm_mpx == yes; then | 
|  | AC_DEFINE(HAVE_MPX_SUPPORT) | 
|  | fi | 
|  |  | 
|  | AC_DEFINE(USE_REGPARMS) | 
|  |  | 
|  | dnl It is always possible to access static and hidden symbols in an | 
|  | dnl position independent way. | 
|  | AC_DEFINE(PI_STATIC_AND_HIDDEN) |