Building glibc 2.5 on Hurd: GCC

[Thomas Schwinge]

Hello!

Needed because of GCC changes.  Not everything is ready for upstream
inclusion.


This is no proper fix, but a workaround to not make argp-enabled programs
segfault on ``PROGRAM --help'' when glibc is build with GCC 4.1.
Reported on
<http://lists.gnu.org/archive/html/bug-hurd/2006-12/msg00064.html>.

--- argp/Makefile~      2004-03-28 16:15:30.000000000 +0200
+++ argp/Makefile       2007-01-29 21:54:59.000000000 +0100
@@ -30,6 +30,7 @@
 
 CFLAGS-argp-help.c = $(uses-callbacks) -fexceptions
 CFLAGS-argp-parse.c = $(uses-callbacks)
-CFLAGS-argp-fmtstream.c = -fexceptions
+# The following `-fno-strict-aliasing' is of course not a proper fix.
+CFLAGS-argp-fmtstream.c = -fexceptions -fno-strict-aliasing
 
 include ../Rules


If building with GCC 4.1, needed for HEAD, glibc-2_5-branch and
glibc-2_3-branch.  Produces one warning in `init-first.c' that should be
fixed.  Reported at <http://savannah.gnu.org/bugs/?17647>.  Continued at
<http://lists.gnu.org/archive/html/bug-hurd/2006-11/msg00249.html>.

Revert Roland patch.  (Part of `-r 1.44' to '-r 1.43').

Index: sysdeps/mach/hurd/i386/init-first.c
===================================================================
RCS file: /cvs/glibc/libc/sysdeps/mach/hurd/i386/init-first.c,v
retrieving revision 1.43.4.1
diff -u -p -r1.43.4.1 init-first.c
--- sysdeps/mach/hurd/i386/init-first.c 23 Oct 2005 01:00:09 -0000      1.43.4.1
+++ sysdeps/mach/hurd/i386/init-first.c 20 Nov 2006 11:05:47 -0000
@@ -320,11 +320,11 @@ first_init (void)
    stack set up just as the user will see it, so it can switch stacks.  */
 
 void
-_dl_init_first (void)
+_dl_init_first (int argc, ...)
 {
   first_init ();
 
-  init ((int *) __builtin_frame_address (0) + 2);
+  init (&argc);
 }
 #endif
 
@@ -351,23 +351,21 @@ strong_alias (posixland_init, __libc_ini
    This poorly-named function is called by static-start.S,
    which should not exist at all.  */
 void
-_hurd_stack_setup (void)
+_hurd_stack_setup (volatile int argc, ...)
 {
-  intptr_t caller = (intptr_t) __builtin_return_address (0);
-
   void doinit (intptr_t *data)
     {
       /* This function gets called with the argument data at TOS.  */
-      void doinit1 (void)
+      void doinit1 (volatile int argc, ...)
        {
-         init ((int *) __builtin_frame_address (0) + 2);
+         init ((int *) &argc);
        }
 
       /* Push the user return address after the argument data, and then
          jump to `doinit1' (above), so it is as if __libc_init_first's
          caller had called `doinit1' with the argument data already on the
          stack.  */
-      *--data = caller;
+      *--data = (&argc)[-1];
       asm volatile ("movl %0, %%esp\n" /* Switch to new outermost stack.  */
                    "movl $0, %%ebp\n" /* Clear outermost frame pointer.  */
                    "jmp *%1" : : "r" (data), "r" (&doinit1) : "sp");
@@ -376,7 +374,7 @@ _hurd_stack_setup (void)
 
   first_init ();
 
-  _hurd_startup ((void **) __builtin_frame_address (0) + 2, &doinit);
+  _hurd_startup ((void **) &argc, &doinit);
 }
 #endif

Make the code work with GCC 4.1.  This is essentially what Roland had
done -- moving the resolution of the return address out of the nested
subfunction -- but this time without replacing it with
`__builtin_return_address'.

Index: sysdeps/mach/hurd/i386/init-first.c
===================================================================
RCS file: /cvs/glibc/libc/sysdeps/mach/hurd/i386/init-first.c,v
retrieving revision 1.43.4.1
diff -u -p -r1.43.4.1 init-first.c
--- sysdeps/mach/hurd/i386/init-first.c 23 Oct 2005 01:00:09 -0000      1.43.4.1
+++ sysdeps/mach/hurd/i386/init-first.c 20 Nov 2006 11:05:47 -0000
@@ -353,6 +355,8 @@
 void
 _hurd_stack_setup (volatile int argc, ...)
 {
+  intptr_t caller = (&argc)[-1];
+
   void doinit (intptr_t *data)
     {
       /* This function gets called with the argument data at TOS.  */
@@ -365,7 +369,7 @@
          jump to `doinit1' (above), so it is as if __libc_init_first's
          caller had called `doinit1' with the argument data already on the
          stack.  */
-      *--data = (&argc)[-1];
+      *--data = caller;
       asm volatile ("movl %0, %%esp\n" /* Switch to new outermost stack.  */
                    "movl $0, %%ebp\n" /* Clear outermost frame pointer.  */
                    "jmp *%1" : : "r" (data), "r" (&doinit1) : "sp");

Cosmetical and documentation fixes.

Index: sysdeps/mach/hurd/i386/init-first.c
===================================================================
RCS file: /cvs/glibc/libc/sysdeps/mach/hurd/i386/init-first.c,v
retrieving revision 1.43.4.1
diff -u -p -r1.43.4.1 init-first.c
--- sysdeps/mach/hurd/i386/init-first.c 23 Oct 2005 01:00:09 -0000      1.43.4.1
+++ sysdeps/mach/hurd/i386/init-first.c 20 Nov 2006 11:05:47 -0000
@@ -243,8 +243,8 @@ init (int *data)
         be the return address for `init1'; we will jump there with NEWSP
         as the stack pointer.  */
       *--newsp = data[-1];
-      ((void **) data)[-1] = switch_stacks;
-      /* Force NEWSP into %ecx and &init1 into %eax, which are not restored
+      data[-1] = (int) &switch_stacks;
+      /* Force NEWSP into %eax and &init1 into %ecx, which are not restored
         by function return.  */
       asm volatile ("# a %0 c %1" : : "a" (newsp), "c" (&init1));
     }


In HEAD, but not yet in glibc-2_5-branch and glibc-2_3-branch.  Needed
when building with GCC 4.0 (I think) and newer.  Reported on
<http://savannah.gnu.org/bugs/?17808>.

2006-10-10  Roland McGrath  <roland@frob.com>

        * sysdeps/mach/hurd/utimes.c: Use a union to avoid an improper cast.
        * sysdeps/mach/hurd/futimes.c: Likewise.
        * sysdeps/mach/hurd/lutimes.c: Likewise.

diff -x CVS -ru sysdeps/mach/hurd/futimes.c ../HEAD/sysdeps/mach/hurd/futimes.c
--- sysdeps/mach/hurd/futimes.c 2006-12-18 00:35:54.000000000 +0100
+++ ../HEAD/sysdeps/mach/hurd/futimes.c 2006-10-10 11:28:40.000000000 +0200
@@ -28,20 +28,24 @@
 int
 __futimes (int fd, const struct timeval tvp[2])
 {
-  struct timeval timevals[2];
+  union tv
+  {
+    struct timeval tv;
+    time_value_t tvt;
+  };
+  const union tv *u = (const union tv *) tvp;
+  union tv nulltv[2];
   error_t err;
 
   if (tvp == NULL)
     {
       /* Setting the number of microseconds to `-1' tells the
          underlying filesystems to use the current time.  */
-      timevals[1].tv_usec = timevals[0].tv_usec = (time_t)-1;
-      tvp = timevals;
+      nulltv[0].tvt.microseconds = nulltv[1].tvt.microseconds = -1;
+      u = nulltv;
     }
 
-  err = HURD_DPORT_USE (fd, __file_utimes (port,
-                                          *(time_value_t *) &tvp[0],
-                                          *(time_value_t *) &tvp[1]));
+  err = HURD_DPORT_USE (fd, __file_utimes (port, u[0].tvt, u[1].tvt));
   return err ? __hurd_dfail (fd, err) : 0;
 }
 weak_alias (__futimes, futimes)
diff -x CVS -ru sysdeps/mach/hurd/lutimes.c ../HEAD/sysdeps/mach/hurd/lutimes.c
--- sysdeps/mach/hurd/lutimes.c 2006-12-18 00:35:54.000000000 +0100
+++ ../HEAD/sysdeps/mach/hurd/lutimes.c 2006-10-10 11:28:40.000000000 +0200
@@ -28,7 +28,13 @@
 int
 __lutimes (const char *file, const struct timeval tvp[2])
 {
-  struct timeval timevals[2];
+  union tv
+  {
+    struct timeval tv;
+    time_value_t tvt;
+  };
+  const union tv *u = (const union tv *) tvp;
+  union tv nulltv[2];
   error_t err;
   file_t port;
 
@@ -36,15 +42,14 @@
     {
       /* Setting the number of microseconds to `-1' tells the
          underlying filesystems to use the current time.  */
-      timevals[1].tv_usec = timevals[0].tv_usec = (time_t)-1;
-      tvp = timevals;
+      nulltv[0].tvt.microseconds = nulltv[1].tvt.microseconds = -1;
+      u = nulltv;
     }
 
   port = __file_name_lookup (file, O_NOLINK, 0);
   if (port == MACH_PORT_NULL)
     return -1;
-  err = __file_utimes (port,
-                      *(time_value_t *) &tvp[0], *(time_value_t *) &tvp[1]);
+  err = __file_utimes (port, u[0].tvt, u[1].tvt);
   __mach_port_deallocate (__mach_task_self (), port);
   if (err)
     return __hurd_fail (err);
diff -x CVS -ru sysdeps/mach/hurd/utimes.c ../HEAD/sysdeps/mach/hurd/utimes.c
--- sysdeps/mach/hurd/utimes.c  2006-12-18 00:35:54.000000000 +0100
+++ ../HEAD/sysdeps/mach/hurd/utimes.c  2006-10-10 11:28:40.000000000 +0200
@@ -28,7 +29,13 @@
      const char *file;
      const struct timeval tvp[2];
 {
-  struct timeval timevals[2];
+  union tv
+  {
+    struct timeval tv;
+    time_value_t tvt;
+  };
+  const union tv *u = (const union tv *) tvp;
+  union tv nulltv[2];
   error_t err;
   file_t port;
 
@@ -36,19 +43,17 @@
     {
       /* Setting the number of microseconds to `-1' tells the
          underlying filesystems to use the current time.  */
-      timevals[1].tv_usec = timevals[0].tv_usec = (time_t)-1;
-      tvp = timevals;
+      nulltv[0].tvt.microseconds = nulltv[1].tvt.microseconds = -1;
+      u = nulltv;
     }
 
   port = __file_name_lookup (file, 0, 0);
   if (port == MACH_PORT_NULL)
     return -1;
-  err = __file_utimes (port,
-                      *(time_value_t *) &tvp[0], *(time_value_t *) &tvp[1]);
+  err = __file_utimes (port, u[0].tvt, u[1].tvt);
   __mach_port_deallocate (__mach_task_self (), port);
   if (err)
     return __hurd_fail (err);
   return 0;
 }
-
 weak_alias (__utimes, utimes)


Regards,
 Thomas

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