glibc/sysdeps/arm/configure.ac

GLIBC_PROVIDES dnl See aclocal.m4 in the top level source directory.
# Local configure fragment for sysdeps/arm.

# We check to see if the compiler and flags are
# selecting the hard-float ABI and if they are then
# we set libc_cv_arm_pcs_vfp to yes which causes
# HAVE_ARM_PCS_VFP to be defined in config.h and
# in include/libc-symbols.h and thus available to
# shlib-versions to select the appropriate name for
# the dynamic linker via %ifdef.
AC_CACHE_CHECK([whether the compiler is using the ARM hard-float ABI],
  [libc_cv_arm_pcs_vfp],
  [AC_EGREP_CPP(yes,[#ifdef __ARM_PCS_VFP
		      yes
		     #endif
  ], libc_cv_arm_pcs_vfp=yes, libc_cv_arm_pcs_vfp=no)])
if test $libc_cv_arm_pcs_vfp = yes; then
  AC_DEFINE(HAVE_ARM_PCS_VFP)
  LIBC_CONFIG_VAR([default-abi], [hard])
else
  LIBC_CONFIG_VAR([default-abi], [soft])
fi

AC_CACHE_CHECK([whether PC-relative relocs in movw/movt work properly],
	       libc_cv_arm_pcrel_movw, [
cat > conftest.s <<\EOF
	.syntax unified
	.arm
	.arch armv7-a

	.text
	.globl foo
	.type foo,%function
foo:	movw r0, #:lower16:symbol - 1f - 8
	movt r0, #:upper16:symbol - 1f - 8
1:	add r0, pc
	@ And now a case with a local symbol.
	movw r0, #:lower16:3f - 2f - 8
	movt r0, #:upper16:3f - 2f - 8
2:	add r0, pc
	bx lr

.data
	.globl symbol
	.hidden symbol
symbol:	.long 23
3:	.long 17
EOF
libc_cv_arm_pcrel_movw=no
${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS \
	 -nostartfiles -nostdlib -shared \
	 -o conftest.so conftest.s 1>&AS_MESSAGE_LOG_FD 2>&AS_MESSAGE_LOG_FD &&
LC_ALL=C $READELF -dr conftest.so > conftest.dr 2>&AS_MESSAGE_LOG_FD &&
{
  cat conftest.dr 1>&AS_MESSAGE_LOG_FD
  grep -F 'TEXTREL
R_ARM_NONE' conftest.dr > /dev/null || libc_cv_arm_pcrel_movw=yes
}
rm -f conftest*])
if test $libc_cv_arm_pcrel_movw = yes; then
  AC_DEFINE([ARM_PCREL_MOVW_OK])
fi

# This was buggy in assemblers from GNU binutils versions before 2.25.1
# (it's known to be broken in 2.24 and 2.25; see
# https://sourceware.org/bugzilla/show_bug.cgi?id=18383).
AC_CACHE_CHECK([whether TPOFF relocs with addends are assembled correctly],
	       libc_cv_arm_tpoff_addend, [
cat > conftest.s <<\EOF
	.syntax unified
	.arm
	.arch armv7-a

	.text
foo:
	.word tbase(tpoff)+4

	.section .tdata,"awT",%progbits
	.word -4
tbase:	.word 0
	.word 4
EOF
libc_cv_arm_tpoff_addend=no
${CC-cc} -c $CFLAGS $CPPFLAGS \
	 -o conftest.o conftest.s 1>&AS_MESSAGE_LOG_FD 2>&AS_MESSAGE_LOG_FD &&
LC_ALL=C $READELF -x.text conftest.o > conftest.x 2>&AS_MESSAGE_LOG_FD &&
{
  cat conftest.x 1>&AS_MESSAGE_LOG_FD
  $AWK 'BEGIN { result = 2 }
$1 ~ /0x0+/ && $2 ~ /[[0-9a-f]]+/ {
# Check for little-endian or big-endian encoding of 4 in the in-place addend.
  result = ($2 == "04000000" || $2 == "00000004") ? 0 : 1
}
END { exit(result) }
' conftest.x 2>&AS_MESSAGE_LOG_FD && libc_cv_arm_tpoff_addend=yes
}
rm -f conftest*])
if test $libc_cv_arm_tpoff_addend = no; then
  LIBC_CONFIG_VAR([test-xfail-tst-tlsalign], [yes])
  LIBC_CONFIG_VAR([test-xfail-tst-tlsalign-static], [yes])
fi


libc_cv_gcc_unwind_find_fde=no

# Remove -fno-unwind-tables that was added in sysdeps/arm/preconfigure.ac.
CFLAGS=${CFLAGS% -fno-unwind-tables}