glibc/sysdeps/powerpc/powerpc64/configure.ac
Fangrui Song 098a657fe4 elf: Replace PI_STATIC_AND_HIDDEN with opposite HIDDEN_VAR_NEEDS_DYNAMIC_RELOC
PI_STATIC_AND_HIDDEN indicates whether accesses to internal linkage
variables and hidden visibility variables in a shared object (ld.so)
need dynamic relocations (usually R_*_RELATIVE). PI (position
independent) in the macro name is a misnomer: a code sequence using GOT
is typically position-independent as well, but using dynamic relocations
does not meet the requirement.

Not defining PI_STATIC_AND_HIDDEN is legacy and we expect that all new
ports will define PI_STATIC_AND_HIDDEN. Current ports defining
PI_STATIC_AND_HIDDEN are more than the opposite. Change the configure
default.

No functional change.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2022-04-26 09:26:22 -07:00

46 lines
1.5 KiB
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GLIBC_PROVIDES dnl See aclocal.m4 in the top level source directory.
# Local configure fragment for sysdeps/powerpc/powerpc64.
AC_DEFINE(HIDDEN_VAR_NEEDS_DYNAMIC_RELOC)
AC_CACHE_CHECK(for support for overlapping .opd entries,
libc_cv_overlapping_opd, [dnl
libc_cv_overlapping_opd=no
echo 'void foo (void) {}' > conftest.c
if AC_TRY_COMMAND(${CC-cc} $CFLAGS $CPPFLAGS -S conftest.c -o conftest.s 1>&AS_MESSAGE_LOG_FD); then
changequote(,)dnl
if grep '\.TOC\.@tocbase' conftest.s > /dev/null; then
if grep '\.TOC\.@tocbase[ ]*,[ ]*0' conftest.s > /dev/null; then
:
else
libc_cv_overlapping_opd=yes
fi
fi
changequote([,])dnl
fi
rm -f conftest.c conftest.s
])
if test x$libc_cv_overlapping_opd = xyes; then
AC_DEFINE(USE_PPC64_OVERLAPPING_OPD)
fi
# We check if compiler supports @notoc generation since there is no
# gain by enabling it if it will be optimized away by the linker.
# It also helps linkers that might not optimize it and end up
# generating stubs with ISA 3.1 instruction even targetting older ISA.
AC_CACHE_CHECK([if the compiler supports @notoc],
libc_cv_ppc64_notoc, [dnl
cat > conftest.c <<EOF
int bar (void);
int foo (void) { return bar () + 1; }
EOF
libc_cv_ppc64_notoc=no
if AC_TRY_COMMAND([${CC-cc} $libc_cv_cc_submachine $CFLAGS $CPPFLAGS -S -o conftest.s conftest.c]) \
&& AC_TRY_COMMAND([grep -q -E 'bar@notoc' conftest.s])
then
libc_cv_ppc64_notoc=yes
fi
rm -rf conftest.*])
AS_IF([test x$libc_cv_ppc64_notoc = xyes],
[AC_DEFINE(USE_PPC64_NOTOC)])