glibc/sysdeps/loongarch/configure.ac

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

dnl It is always possible to access static and hidden symbols in an
dnl position independent way.
AC_DEFINE(HIDDEN_VAR_NEEDS_DYNAMIC_RELOC)

dnl Test if the toolchain is new enough for static PIE.
dnl We need a GAS supporting explicit reloc (older GAS produces stack-based
dnl reloc and triggers an internal error in the linker).  And, we need GCC to
dnl pass the correct linker flags for static PIE.  GCC >= 13 and GAS >= 2.40
dnl satisify the requirement, but a distro may backport static PIE support into
dnl earlier GCC or Binutils releases as well.
AC_CACHE_CHECK([if the toolchain is sufficient to build static PIE on LoongArch],
libc_cv_static_pie_on_loongarch, [
  cat > conftest1.S << EOF
.global _start
.type _start, @function
_start:
  li.w \$a7, 93
  /* This ensures the assembler supports explicit reloc.  */
  pcalau12i \$a0, %pc_hi20(x)
  ld.w \$a0, \$a0, %pc_lo12(x)
  syscall 0

.data
x:
  .word 0
  /* This should produce an R_LARCH_RELATIVE in the static PIE.  */
  .dword _start
EOF
  cat > conftest2.S << EOF
.global f
.type f, @function
f:
  /* The linker should be able to handle this and produce a PLT entry.  */
  la.pcrel \$t0, \$t0, external_func
  jirl \$zero, \$t0, 0
EOF

  libc_cv_static_pie_on_loongarch=no
  if AC_TRY_COMMAND([${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS -static-pie -nostdlib -fPIE -o conftest1 conftest1.S]) \
     && AC_TRY_COMMAND([LC_ALL=C $READELF -Wr conftest1 | grep -q R_LARCH_RELATIVE]) \
     && AC_TRY_COMMAND([${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS -shared -fPIC -o conftest2.so conftest2.S]) \
     && AC_TRY_COMMAND([LC_ALL=C $READELF -Wr conftest2.so | grep -q 'R_LARCH_JUMP_SLOT.*external_func'])
  then
    libc_cv_static_pie_on_loongarch=yes
  fi
  rm -rf conftest* ])

if test "$libc_cv_static_pie_on_loongarch" = yes; then
  AC_DEFINE(SUPPORT_STATIC_PIE)
fi