stdio: Remove the usage of $(fno-unit-at-a-time) for siglist.c

The siglist.c is built with -fno-toplevel-reorder to avoid compiler
to reorder the compat assembly directives due an assembler
issue [1] (fixed on 2.39).

This patch removes the compiler flags by split the compat symbol
generation in two phases.  First the __sys_siglist and __sys_sigabbrev
without any compat symbol directive is preprocessed to generate an
assembly source code.  This generate assembly is then used as input
on a platform agnostic siglist.S which then creates the compat
definitions.  This prevents compiler to move any compat directive
prior the _sys_errlist definition itself.

Checked on a make check run-built-tests=no on all affected ABIs.

Reviewed-by: Fangrui Song <maskray@google.com>

include/signal.h

@@ -14,10 +14,8 @@ libc_hidden_proto (__sigpause)
 libc_hidden_proto (raise)
 libc_hidden_proto (__libc_current_sigrtmin)
 libc_hidden_proto (__libc_current_sigrtmax)
-extern const char * const __sys_siglist[_NSIG];
+extern const char * const __sys_siglist[_NSIG] attribute_hidden;
-libc_hidden_proto (__sys_siglist)
+extern const char * const __sys_sigabbrev[_NSIG] attribute_hidden;
-extern const char * const __sys_sigabbrev[_NSIG];
-libc_hidden_proto (__sys_sigabbrev)
 
 /* Now define the internal interfaces.  */
 extern __sighandler_t __bsd_signal (int __sig, __sighandler_t __handler);

stdio-common/Makefile

@@ -215,6 +215,8 @@ tests := \
 generated += \
   errlist-data-aux-shared.S \
   errlist-data-aux.S \
+  siglist-aux-shared.S \
+  siglist-aux.S \
   # generated
 
 test-srcs = tst-unbputc tst-printf tst-printfsz-islongdouble
@@ -265,6 +267,17 @@ $(objpfx)errlist-data-aux.S: errlist-data-gen.c
 $(objpfx)errlist-data.os: $(objpfx)errlist-data-aux-shared.S
 $(objpfx)errlist-data.o: $(objpfx)errlist-data-aux.S
 
+$(objpfx)siglist-aux-shared.S: siglist-gen.c
+	$(make-target-directory)
+	$(compile-command.c) $(pic-cppflags) $(pic-ccflag) $(no-stack-protector) -S
+
+$(objpfx)siglist-aux.S: siglist-gen.c
+	$(make-target-directory)
+	$(compile-command.c) $(pie-default) $(no-stack-protector) -S
+
+$(objpfx)siglist.os: $(objpfx)siglist-aux-shared.S
+$(objpfx)siglist.o: $(objpfx)siglist-aux.S
+
 ifeq ($(run-built-tests),yes)
 LOCALES := \
   de_DE.ISO-8859-1 \
@@ -353,7 +366,6 @@ CFLAGS-isoc99_vfscanf.c += -fexceptions
 CFLAGS-isoc99_vscanf.c += -fexceptions
 CFLAGS-isoc99_fscanf.c += -fexceptions
 CFLAGS-isoc99_scanf.c += -fexceptions
-CFLAGS-siglist.c += $(fno-unit-at-a-time)
 
 # scanf14a.c and scanf16a.c test a deprecated extension which is no
 # longer visible under most conformance levels; see the source files

stdio-common/siglist-gen.c

@@ -26,7 +26,6 @@ const char *const __sys_siglist[NSIG] =
 #include <siglist.h>
 #undef init_sig
 };
-libc_hidden_def (__sys_siglist)
 
 const char *const __sys_sigabbrev[NSIG] =
 {
@@ -34,6 +33,3 @@ const char *const __sys_sigabbrev[NSIG] =
 #include <siglist.h>
 #undef init_sig
 };
-libc_hidden_def (__sys_sigabbrev)
-
-#include <siglist-compat.c>

stdio-common/siglist.S

@@ -0,0 +1,7 @@
+#ifdef SHARED
+# include "siglist-aux-shared.S"
+#else
+# include "siglist-aux.S"
+#endif
+
+#include <siglist-compat.h>

sysdeps/generic/siglist-compat-def.h

@@ -28,20 +28,23 @@
    sys_sigabbrev alias to __sys_sigabbrev.  Both target alias are
    define in siglist.c.  */
 #define DEFINE_COMPAT_SIGLIST(NUMBERSIG, VERSION) 			     \
-  declare_symbol_alias (__ ## VERSION ## _sys_siglist,			     \
+  declare_object_symbol_alias (__ ## VERSION ## _sys_siglist,		     \
 			       __sys_siglist,				     \
-			object,	NUMBERSIG * (ULONG_WIDTH / UCHAR_WIDTH));    \
+			       NUMBERSIG * (ULONG_WIDTH / UCHAR_WIDTH))      \
-  declare_symbol_alias (__ ## VERSION ## sys_siglist,			     \
+			       ASM_LINE_SEP				     \
+  declare_object_symbol_alias (__ ## VERSION ## sys_siglist,		     \
 			       __sys_siglist,				     \
-			object,	NUMBERSIG * (ULONG_WIDTH / UCHAR_WIDTH));    \
+			       NUMBERSIG * (ULONG_WIDTH / UCHAR_WIDTH))      \
-  declare_symbol_alias (__ ## VERSION ## _sys_sigabbrev,		     \
+			       ASM_LINE_SEP				     \
+  declare_object_symbol_alias (__ ## VERSION ## _sys_sigabbrev,		     \
 			       __sys_sigabbrev,				     \
-			object, NUMBERSIG * (ULONG_WIDTH / UCHAR_WIDTH));    \
+			       NUMBERSIG * (ULONG_WIDTH / UCHAR_WIDTH))      \
+			       ASM_LINE_SEP				     \
   compat_symbol (libc, __## VERSION ## _sys_siglist,   _sys_siglist,	     \
-		 VERSION);						     \
+		 VERSION) ASM_LINE_SEP					     \
   compat_symbol (libc, __## VERSION ## sys_siglist,    sys_siglist,	     \
-		 VERSION);						     \
+		 VERSION) ASM_LINE_SEP					     \
   compat_symbol (libc, __## VERSION ## _sys_sigabbrev, sys_sigabbrev,	     \
-		 VERSION);						     \
+		 VERSION)
 
 #endif

sysdeps/generic/siglist-compat.c

@@ -1 +0,0 @@
-/* Empty.  */

sysdeps/mach/hurd/siglist-compat.h

@@ -16,12 +16,15 @@
    License along with the GNU C Library; if not, see
    <https://www.gnu.org/licenses/>.  */
 
-#include <siglist-compat.h>
+#include <siglist-compat-def.h>
+/* To get _NSIG definition.  */
+#define _SIGNAL_H
+#include <bits/signum-generic.h>
 
 #if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_1)
 DEFINE_COMPAT_SIGLIST (33, GLIBC_2_0)
 #endif
 
 #if SHLIB_COMPAT (libc, GLIBC_2_1, GLIBC_2_32)
-DEFINE_COMPAT_SIGLIST (NSIG, GLIBC_2_1)
+DEFINE_COMPAT_SIGLIST (_NSIG, GLIBC_2_1)
 #endif

sysdeps/unix/sysv/linux/siglist-compat.h

@@ -16,7 +16,10 @@
    License along with the GNU C Library; if not, see
    <https://www.gnu.org/licenses/>.  */
 
-#include <siglist-compat.h>
+#include <siglist-compat-def.h>
+/* To get _NSIG definition.  */
+#define _SIGNAL_H
+#include <bits/signum-generic.h>
 
 #if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_1)
 DEFINE_COMPAT_SIGLIST (32, GLIBC_2_0)
@@ -27,5 +30,5 @@ DEFINE_COMPAT_SIGLIST (64, GLIBC_2_1)
 #endif
 
 #if SHLIB_COMPAT (libc, GLIBC_2_3_3, GLIBC_2_32)
-DEFINE_COMPAT_SIGLIST (NSIG, GLIBC_2_3_3)
+DEFINE_COMPAT_SIGLIST (_NSIG, GLIBC_2_3_3)
 #endif