[v4,RESEND,1/2] Move NO_PIE_CFLAGS logic from gcc to libgcc
Commit Message
My goal is to be able to build libgcc cleanly in isolation --- today one
needs to figure `make ...` misc things in the gcc subdir.
Following Andrew Pinski's suggestions in
https://gcc.gnu.org/pipermail/gcc-patches/2025-July/689683.html, this
commit moves the NO_PIE_CFLAGS logic.
gcc/ChangeLog:
* Makefile.in:: Remove NO_PIE_CFLAGS logic, since it is now in
libgcc.
* configure: Regenerate.
* configure.ac: Remove the enable_default_pie substitution, since
libgcc now has its own logic.
libgcc/ChangeLog:
* Makefile.in: Define NO_PIE_CFLAGS make variable via autoconf
substitution.
* configure: Regenerate.
* configure.ac: New configure check to define NO_PIE_CFLAGS
using the algorithm Andrew asked for in the linked mail.
Suggested-by: Andrew Pinski <quic_apinski@quicinc.com>
Signed-off-by: John Ericson <git@JohnEricson.me>
---
gcc/Makefile.in | 6 ------
gcc/configure | 6 ++----
gcc/configure.ac | 1 -
libgcc/Makefile.in | 2 ++
libgcc/configure | 35 +++++++++++++++++++++++++++++++++++
libgcc/configure.ac | 14 ++++++++++++++
6 files changed, 53 insertions(+), 11 deletions(-)
Comments
On Sun, 7 Dec 2025, John Ericson wrote:
> My goal is to be able to build libgcc cleanly in isolation --- today one
> needs to figure `make ...` misc things in the gcc subdir.
>
> Following Andrew Pinski's suggestions in
> https://gcc.gnu.org/pipermail/gcc-patches/2025-July/689683.html, this
> commit moves the NO_PIE_CFLAGS logic.
>
> gcc/ChangeLog:
>
> * Makefile.in:: Remove NO_PIE_CFLAGS logic, since it is now in
> libgcc.
> * configure: Regenerate.
> * configure.ac: Remove the enable_default_pie substitution, since
> libgcc now has its own logic.
>
> libgcc/ChangeLog:
>
> * Makefile.in: Define NO_PIE_CFLAGS make variable via autoconf
> substitution.
> * configure: Regenerate.
> * configure.ac: New configure check to define NO_PIE_CFLAGS
> using the algorithm Andrew asked for in the linked mail.
This is another patch I approved in July in the absence of more specific
maintainer objections.
@@ -2504,12 +2504,6 @@ libgcc.mvars: config.status Makefile specs xgcc$(exeext)
echo GCC_CFLAGS = '$(GCC_CFLAGS)' >> tmp-libgcc.mvars
echo INHIBIT_LIBC_CFLAGS = '$(INHIBIT_LIBC_CFLAGS)' >> tmp-libgcc.mvars
echo TARGET_SYSTEM_ROOT = '$(TARGET_SYSTEM_ROOT)' >> tmp-libgcc.mvars
- if test @enable_default_pie@ = yes; then \
- NO_PIE_CFLAGS="-fno-PIE"; \
- else \
- NO_PIE_CFLAGS=; \
- fi; \
- echo NO_PIE_CFLAGS = "$$NO_PIE_CFLAGS" >> tmp-libgcc.mvars
mv tmp-libgcc.mvars libgcc.mvars
@@ -635,7 +635,6 @@ LIBOBJS
CET_HOST_FLAGS
LD_PICFLAG
PICFLAG
-enable_default_pie
libgccjit_version
enable_host_bind_now
LIBGDIAGNOSTICS
@@ -21877,7 +21876,7 @@ else
lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
lt_status=$lt_dlunknown
cat > conftest.$ac_ext <<_LT_EOF
-#line 21880 "configure"
+#line 21879 "configure"
#include "confdefs.h"
#if HAVE_DLFCN_H
@@ -21983,7 +21982,7 @@ else
lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
lt_status=$lt_dlunknown
cat > conftest.$ac_ext <<_LT_EOF
-#line 21986 "configure"
+#line 21985 "configure"
#include "confdefs.h"
#if HAVE_DLFCN_H
@@ -34939,7 +34938,6 @@ $as_echo "#define ENABLE_DEFAULT_PIE 1" >>confdefs.h
fi
-
# Check if -fno-PIE works.
{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for -fno-PIE option" >&5
$as_echo_n "checking for -fno-PIE option... " >&6; }
@@ -7765,7 +7765,6 @@ if test x$enable_default_pie = xyes ; then
AC_DEFINE(ENABLE_DEFAULT_PIE, 1,
[Define if your target supports default PIE and it is enabled.])
fi
-AC_SUBST([enable_default_pie])
# Check if -fno-PIE works.
AC_CACHE_CHECK([for -fno-PIE option],
@@ -298,6 +298,8 @@ override CFLAGS := $(filter-out -fprofile-generate -fprofile-use,$(CFLAGS))
INTERNAL_CFLAGS = $(CFLAGS) $(LIBGCC2_CFLAGS) $(HOST_LIBGCC2_CFLAGS) \
$(INCLUDES) @set_have_cc_tls@ @set_use_emutls@
+NO_PIE_CFLAGS = @NO_PIE_CFLAGS@
+
# Options to use when compiling crtbegin/end.
CRTSTUFF_CFLAGS = -O2 $(GCC_CFLAGS) $(INCLUDES) $(MULTILIB_CFLAGS) -g0 \
$(NO_PIE_CFLAGS) -finhibit-size-directive -fno-inline -fno-exceptions \
@@ -610,6 +610,7 @@ accel_dir_suffix
use_tm_clone_registry
force_explicit_eh_registry
CET_FLAGS
+NO_PIE_CFLAGS
fixed_point
enable_decimal_float
decimal_float
@@ -4836,6 +4837,40 @@ $as_echo "$libgcc_cv_fixed_point" >&6; }
fixed_point=$libgcc_cv_fixed_point
+# Check whether the compiler defines __PIE__ by default, so -fno-PIE is needed.
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether the compiler defines __PIE__" >&5
+$as_echo_n "checking whether the compiler defines __PIE__... " >&6; }
+if ${libgcc_cv_no_pie_cflags+:} false; then :
+ $as_echo_n "(cached) " >&6
+else
+ cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h. */
+
+#ifdef __PIE__
+#error __PIE__ defined
+#endif
+
+int
+main ()
+{
+
+ ;
+ return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+ libgcc_cv_no_pie_cflags=''
+else
+ libgcc_cv_no_pie_cflags='-fno-PIE'
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $libgcc_cv_no_pie_cflags" >&5
+$as_echo "$libgcc_cv_no_pie_cflags" >&6; }
+
+NO_PIE_CFLAGS=$libgcc_cv_no_pie_cflags
+
+
# For platforms with the unwind ABI which includes an unwind library,
# libunwind, we can choose to use the system libunwind.
# config.gcc also contains tests of with_system_libunwind.
@@ -258,6 +258,20 @@ AC_CACHE_CHECK([whether fixed-point is supported], [libgcc_cv_fixed_point],
fixed_point=$libgcc_cv_fixed_point
AC_SUBST(fixed_point)
+# Check whether the compiler defines __PIE__ by default, so -fno-PIE is needed.
+AC_CACHE_CHECK([whether the compiler defines __PIE__], [libgcc_cv_no_pie_cflags],
+ [AC_COMPILE_IFELSE(
+ [AC_LANG_PROGRAM([[
+#ifdef __PIE__
+#error __PIE__ defined
+#endif
+ ]], [[]])],
+ [libgcc_cv_no_pie_cflags=''],
+ [libgcc_cv_no_pie_cflags='-fno-PIE'])])
+
+NO_PIE_CFLAGS=$libgcc_cv_no_pie_cflags
+AC_SUBST([NO_PIE_CFLAGS])
+
# For platforms with the unwind ABI which includes an unwind library,
# libunwind, we can choose to use the system libunwind.
# config.gcc also contains tests of with_system_libunwind.