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 if linker can convert "movl main@GOT(%ebx), %eax" to

dnl "leal main@GOTOFF(%ebx), %eax" for static PIE.

if test "$static_pie" = yes; then

  AC_CACHE_CHECK(for linker static PIE support, libc_cv_ld_static_pie, [dnl

cat > conftest.s <<\EOF

	.text

	.global _start

_start:

	movl	_start@GOT(%ebx), %eax

EOF

  libc_cv_pie_option="-Wl,-pie"

  libc_cv_ld_static_pie=no

  if AC_TRY_COMMAND(${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS -nostartfiles -nostdlib $no_ssp $libc_cv_pie_option -o conftest conftest.s 1>&AS_MESSAGE_LOG_FD); then

    if $READELF -r conftest | grep 'There are no relocations in this file.' > /dev/null; then

      libc_cv_ld_static_pie=yes

    fi

  fi

rm -f conftest*])

  if test "$libc_cv_ld_static_pie" != yes; then

    AC_MSG_ERROR([linker support for static PIE needed])

  fi

fi

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

dnl It is always possible to access static and hidden symbols in an

dnl position independent way.

AC_DEFINE(PI_STATIC_AND_HIDDEN)

dnl When multi-arch is enabled, all external functions must be called

dnl via PIC PLT in PIE, which requires setting up EBX register.

if test x"$multi_arch" != xno; then

  AC_DEFINE(NO_HIDDEN_EXTERN_FUNC_IN_PIE)

fi