| 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 |
