Re: [PATCH] PowerPC: define _CALL_ELF if compiler does not define it

[Adhemerval Zanella <azanella at linux dot vnet dot ibm dot com>]

On 21-03-2014 17:10, Roland McGrath wrote:
> It seems questionable to modify CFLAGS for this.  It probably belongs in
> CPPFLAGS, to begin with.  But I'm not sure I like it modifying the user's
> CPPFLAGS either.  It might be best to add a new config.make variable for
> configure-deduced (as opposed to user-specified) CPPFLAGS and accumulate
> into that.  It would be an analogue to config-extra-cflags
> (libc_extra_cflags in configure).  While you're at it, generalize
> libc_extra_cflags so it accumulates and could be used by sysdeps configure
> fragments, rather than just being single-purpose as it is today.
>
Something like this:

This patch make the configure adds -D_CALL_ELF=1 when compiler does
not define _CALL_ELF (versions before powerpc64le support).  It cleans
up compiler warnings on old compiler where _CALL_ELF is not defined
on powerpc64(be) builds.

It does by add a new config.make variable for configure-deduced
CPPFLAGS and accumulate into that (confix-extra-cppflags).  It also
generalizes libc_extra_cflags so it accumulates in sysdeps configure
fragmenets.

--

	* Makeconfig (CPPFLAGS): Add config-extra-cppflags t list.
	* config.make.in (config-extra-cppflags): Set it from
	libc_extra_cppflags.
	* configure.ac (libc_extra_cflags): Make it accumulate over
	configure fragments.
	(libc_extra_cppflags): New flag.
	* configure. Regenerate.
	* sysdeps/unix/sysv/linux/powerpc/powerpc64/configure.ac
	(libc_cv_ppc64_def_call_elf): Define it to yes if compiler does not set
	_CALL_ELF and add -D_CALL_ELF=1 to libc_extra_cppflags.
	* sysdeps/unix/sysv/linux/powerpc/powerpc64/configure: Regenerate.

---

diff --git a/Makeconfig b/Makeconfig
index 3338ab6..f965398 100644
--- a/Makeconfig
+++ b/Makeconfig
@@ -792,7 +792,8 @@ libio-include = -I$(..)libio
 # Note that we can't use -std=* in CPPFLAGS, because it overrides
 # the implicit -lang-asm and breaks cpp behavior for .S files--notably
 # it causes cpp to stop predefining __ASSEMBLER__.
-CPPFLAGS = $(CPPUNDEFS) $(CPPFLAGS-config) $($(subdir)-CPPFLAGS) \
+CPPFLAGS = $(config-extra-cppflags) $(CPPUNDEFS) $(CPPFLAGS-config) \
+	   $($(subdir)-CPPFLAGS) \
 	   $(+includes) $(defines) \
 	   -include $(..)include/libc-symbols.h $(sysdep-CPPFLAGS) \
 	   $(CPPFLAGS-$(suffix $@)) \
diff --git a/config.make.in b/config.make.in
index 416fb9e..132d179 100644
--- a/config.make.in
+++ b/config.make.in
@@ -37,6 +37,7 @@ cflags-cpu = @libc_cv_cc_submachine@
 asflags-cpu = @libc_cv_cc_submachine@
 
 config-extra-cflags = @libc_extra_cflags@
+config-extra-cppflags = @libc_extra_cppflags@
 config-cflags-nofma = @libc_cv_cc_nofma@
 
 defines = @DEFINES@
diff --git a/configure b/configure
index d4b5edb..ee139bb 100755
--- a/configure
+++ b/configure
@@ -591,6 +591,7 @@ libc_cv_slibdir
 old_glibc_headers
 use_nscd
 libc_cv_gcc_unwind_find_fde
+libc_extra_cppflags
 libc_extra_cflags
 CPPUNDEFS
 sizeof_long_double
@@ -7199,9 +7200,9 @@ fi
 $as_echo "$libc_cv_predef_stack_protector" >&6; }
 libc_extra_cflags=
 if test $libc_cv_predef_stack_protector = yes; then
-  libc_extra_cflags=-fno-stack-protector
+  libc_extra_cflags+=-fno-stack-protector
 fi
-
+libc_extra_cppflags=
 
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether the linker provides __ehdr_start" >&5
 $as_echo_n "checking whether the linker provides __ehdr_start... " >&6; }
@@ -7266,6 +7267,9 @@ $as_echo "running configure fragment for $dir" >&6; }
   fi
 done
 
+
+
+
 if test x$libc_cv_gcc_unwind_find_fde = xyes; then
   $as_echo "#define EXPORT_UNWIND_FIND_FDE 1" >>confdefs.h
 
diff --git a/configure.ac b/configure.ac
index 43bd8a5..46b37b5 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2042,9 +2042,9 @@ esac],
 ])
 libc_extra_cflags=
 if test $libc_cv_predef_stack_protector = yes; then
-  libc_extra_cflags=-fno-stack-protector
+  libc_extra_cflags+=-fno-stack-protector
 fi
-AC_SUBST(libc_extra_cflags)
+libc_extra_cppflags=
 
 AC_CACHE_CHECK([whether the linker provides __ehdr_start],
 	       libc_cv_ehdr_start, [
@@ -2091,6 +2091,9 @@ for dir in $sysnames; do
   fi
 done
 
+AC_SUBST(libc_extra_cflags)
+AC_SUBST(libc_extra_cppflags)
+
 if test x$libc_cv_gcc_unwind_find_fde = xyes; then
   AC_DEFINE(EXPORT_UNWIND_FIND_FDE)
 fi
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/configure b/sysdeps/unix/sysv/linux/powerpc/powerpc64/configure
index fbb6334..7f4a7c4 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/configure
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/configure
@@ -163,4 +163,31 @@ default-abi = 64-v2"
 else
   config_vars="$config_vars
 default-abi = 64-v1"
+  # Compiler that do not support ELFv2 ABI does not define _CALL_ELF
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether the compiler defines _CALL_ELF" >&5
+$as_echo_n "checking whether the compiler defines _CALL_ELF... " >&6; }
+if ${libc_cv_ppc64_def_call_elf+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#ifdef _CALL_ELF
+                         yes
+                       #endif
+
+_ACEOF
+if (eval "$ac_cpp conftest.$ac_ext") 2>&5 |
+  $EGREP "yes" >/dev/null 2>&1; then :
+  libc_cv_ppc64_def_call_elf=yes
+else
+  libc_cv_ppc64_def_call_elf=no
+fi
+rm -f conftest*
+
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $libc_cv_ppc64_def_call_elf" >&5
+$as_echo "$libc_cv_ppc64_def_call_elf" >&6; }
+  if test $libc_cv_ppc64_def_call_elf = no; then
+    libc_extra_cppflags+=" -D_CALL_ELF=1"
+  fi
 fi
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/configure.ac b/sysdeps/unix/sysv/linux/powerpc/powerpc64/configure.ac
index c9cd4bc..5733f79 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/configure.ac
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/configure.ac
@@ -12,4 +12,14 @@ if test $libc_cv_ppc64_elfv2_abi = yes; then
   LIBC_CONFIG_VAR([default-abi], [64-v2])
 else
   LIBC_CONFIG_VAR([default-abi], [64-v1])
+  # Compiler that do not support ELFv2 ABI does not define _CALL_ELF
+  AC_CACHE_CHECK([whether the compiler defines _CALL_ELF],
+    [libc_cv_ppc64_def_call_elf],
+    [AC_EGREP_CPP(yes,[#ifdef _CALL_ELF
+                         yes
+                       #endif
+    ], libc_cv_ppc64_def_call_elf=yes, libc_cv_ppc64_def_call_elf=no)])
+  if test $libc_cv_ppc64_def_call_elf = no; then
+    libc_extra_cppflags+=" -D_CALL_ELF=1"
+  fi
 fi