* Makefile.in (symfile-mem.o): Update dependencies.

* i386-linux-tdep.c (i386_linux_dwarf_signal_frame_p): New.
	(i386_linux_init_abi): Call dwarf2_frame_set_signal_frame_p.
	* inf-ptrace.c (inf_ptrace_attach): Call
	observer_notify_inferior_created.
	* inftarg.c (child_attach): Likewise.
	* symfile-mem.c: Include "observer.h", "auxv.h", and "elf/common.h".
	(symbol_file_add_from_memory): Take NAME argument.  Use it for
	the new BFD's filename.
	(add_symbol_file_from_memory_command): Update call to
	symbol_file_add_from_memory.
	(struct symbol_file_add_from_memory_args, add_vsyscall_page)
	(symbol_file_add_from_memory_wrapper): New.
	(_initialize_symfile_mem): Register add_vsyscall_page as an
	inferior_created observer.

gdb/ChangeLog

@@ -1,3 +1,23 @@
+2004-11-07  Andrew Cagney  <cagney@redhat.com>
+	    Daniel Jacobowitz  <dan@debian.org>
+	    Roland McGrath  <roland@redhat.com>
+
+	* Makefile.in (symfile-mem.o): Update dependencies.
+	* i386-linux-tdep.c (i386_linux_dwarf_signal_frame_p): New.
+	(i386_linux_init_abi): Call dwarf2_frame_set_signal_frame_p.
+	* inf-ptrace.c (inf_ptrace_attach): Call
+	observer_notify_inferior_created.
+	* inftarg.c (child_attach): Likewise.
+	* symfile-mem.c: Include "observer.h", "auxv.h", and "elf/common.h".
+	(symbol_file_add_from_memory): Take NAME argument.  Use it for
+	the new BFD's filename.
+	(add_symbol_file_from_memory_command): Update call to
+	symbol_file_add_from_memory.
+	(struct symbol_file_add_from_memory_args, add_vsyscall_page)
+	(symbol_file_add_from_memory_wrapper): New.
+	(_initialize_symfile_mem): Register add_vsyscall_page as an
+	inferior_created observer.
+
 2004-11-07  Mark Kettenis  <kettenis@gnu.org>
 
 	* m68kbsd-nat.c (m68kbsd_fetch_inferior_registers): Rename from

gdb/Makefile.in

@@ -2620,7 +2620,8 @@ symfile.o: symfile.c $(defs_h) $(bfdlink_h) $(symtab_h) $(gdbtypes_h) \
 	$(hashtab_h) $(readline_h) $(gdb_assert_h) $(block_h) \
 	$(gdb_string_h) $(gdb_stat_h)
 symfile-mem.o: symfile-mem.c $(defs_h) $(symtab_h) $(gdbcore_h) \
-	$(objfiles_h) $(gdbcmd_h) $(target_h) $(value_h) $(symfile_h)
+	$(objfiles_h) $(gdbcmd_h) $(target_h) $(value_h) $(symfile_h) \
+	$(observer_h) $(auxv_h) $(elf_common_h)
 symmisc.o: symmisc.c $(defs_h) $(symtab_h) $(gdbtypes_h) $(bfd_h) \
 	$(symfile_h) $(objfiles_h) $(breakpoint_h) $(command_h) \
 	$(gdb_obstack_h) $(language_h) $(bcache_h) $(block_h) $(gdb_regex_h) \

gdb/i386-linux-tdep.c

@@ -244,6 +244,27 @@ i386_linux_sigtramp_p (struct frame_info *next_frame)
 	  || strcmp ("__restore_rt", name) == 0);
 }
 
+/* Return one if the unwound PC from NEXT_FRAME is in a signal trampoline
+   which may have DWARF-2 CFI.  */
+
+static int
+i386_linux_dwarf_signal_frame_p (struct gdbarch *gdbarch,
+				 struct frame_info *next_frame)
+{
+  CORE_ADDR pc = frame_pc_unwind (next_frame);
+  char *name;
+
+  find_pc_partial_function (pc, &name, NULL, NULL);
+
+  /* If a vsyscall DSO is in use, the signal trampolines may have these
+     names.  */
+  if (name && (strcmp (name, "__kernel_sigreturn") == 0
+	       || strcmp (name, "__kernel_rt_sigreturn") == 0))
+    return 1;
+
+  return 0;
+}
+
 /* Offset to struct sigcontext in ucontext, from <asm/ucontext.h>.  */
 #define I386_LINUX_UCONTEXT_SIGCONTEXT_OFFSET 20
 
@@ -414,6 +435,8 @@ i386_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 
   /* GNU/Linux uses the dynamic linker included in the GNU C Library.  */
   set_gdbarch_skip_solib_resolver (gdbarch, glibc_skip_solib_resolver);
+
+  dwarf2_frame_set_signal_frame_p (gdbarch, i386_linux_dwarf_signal_frame_p);
 }
 
 /* Provide a prototype to silence -Wmissing-prototypes.  */

gdb/inf-ptrace.c

@@ -220,6 +220,10 @@ inf_ptrace_attach (char *args, int from_tty)
 
   inferior_ptid = pid_to_ptid (pid);
   push_target (ptrace_ops_hack);
+
+  /* Do this first, before anything has had a chance to query the
+     inferior's symbol table or similar.  */
+  observer_notify_inferior_created (&current_target, from_tty);
 }
 
 static void

gdb/inftarg.c

@@ -211,6 +211,10 @@ child_attach (char *args, int from_tty)
   
   inferior_ptid = pid_to_ptid (pid);
   push_target (&deprecated_child_ops);
+
+  /* Do this first, before anything has had a chance to query the
+     inferior's symbol table or similar.  */
+  observer_notify_inferior_created (&current_target, from_tty);
 }
 
 #if !defined(CHILD_POST_ATTACH)

gdb/symfile-mem.c

@@ -52,13 +52,19 @@
 #include "target.h"
 #include "value.h"
 #include "symfile.h"
+#include "observer.h"
+#include "auxv.h"
+#include "elf/common.h"
 
 
 /* Read inferior memory at ADDR to find the header of a loaded object file
    and read its in-core symbols out of inferior memory.  TEMPL is a bfd
-   representing the target's format.  */
+   representing the target's format.  NAME is the name to use for this
+   symbol file in messages; it can be NULL or a malloc-allocated string
+   which will be attached to the BFD.  */
 static struct objfile *
-symbol_file_add_from_memory (struct bfd *templ, CORE_ADDR addr, int from_tty)
+symbol_file_add_from_memory (struct bfd *templ, CORE_ADDR addr, char *name,
+			     int from_tty)
 {
   struct objfile *objf;
   struct bfd *nbfd;
@@ -75,7 +81,10 @@ symbol_file_add_from_memory (struct bfd *templ, CORE_ADDR addr, int from_tty)
   if (nbfd == NULL)
     error ("Failed to read a valid object file image from memory.");
 
-  nbfd->filename = xstrdup ("shared object read from target memory");
+  if (name == NULL)
+    nbfd->filename = xstrdup ("shared object read from target memory");
+  else
+    nbfd->filename = name;
 
   if (!bfd_check_format (nbfd, bfd_object))
     {
@@ -129,7 +138,73 @@ add_symbol_file_from_memory_command (char *args, int from_tty)
     error ("\
 Must use symbol-file or exec-file before add-symbol-file-from-memory.");
 
-  symbol_file_add_from_memory (templ, addr, from_tty);
+  symbol_file_add_from_memory (templ, addr, NULL, from_tty);
+}
+
+/* Arguments for symbol_file_add_from_memory_wrapper.  */
+
+struct symbol_file_add_from_memory_args
+{
+  struct bfd *bfd;
+  CORE_ADDR sysinfo_ehdr;
+  char *name;
+  int from_tty;
+};
+
+/* Wrapper function for symbol_file_add_from_memory, for
+   catch_exceptions.  */
+
+static int
+symbol_file_add_from_memory_wrapper (struct ui_out *uiout, void *data)
+{
+  struct symbol_file_add_from_memory_args *args = data;
+
+  symbol_file_add_from_memory (args->bfd, args->sysinfo_ehdr, args->name,
+			       args->from_tty);
+  return 0;
+}
+
+/* Try to add the symbols for the vsyscall page, if there is one.  This function
+   is called via the inferior_created observer.  */
+
+static void
+add_vsyscall_page (struct target_ops *target, int from_tty)
+{
+  CORE_ADDR sysinfo_ehdr;
+
+  if (target_auxv_search (target, AT_SYSINFO_EHDR, &sysinfo_ehdr) > 0
+      && sysinfo_ehdr != (CORE_ADDR) 0)
+    {
+      struct bfd *bfd;
+      struct symbol_file_add_from_memory_args args;
+
+      if (core_bfd != NULL)
+	bfd = core_bfd;
+      else if (exec_bfd != NULL)
+	bfd = exec_bfd;
+      else
+       /* FIXME: cagney/2004-05-06: Should not require an existing
+	  BFD when trying to create a run-time BFD of the VSYSCALL
+	  page in the inferior.  Unfortunately that's the current
+	  interface so for the moment bail.  Introducing a
+	  ``bfd_runtime'' (a BFD created using the loaded image) file
+	  format should fix this.  */
+	{
+	  warning ("could not load vsyscall page because no executable was specified");
+	  warning ("try using the \"file\" command first");
+	  return;
+	}
+      args.bfd = bfd;
+      args.sysinfo_ehdr = sysinfo_ehdr;
+      xasprintf (&args.name, "system-supplied DSO at 0x%s",
+		 paddr_nz (sysinfo_ehdr));
+      /* Pass zero for FROM_TTY, because the action of loading the
+	 vsyscall DSO was not triggered by the user, even if the user
+	 typed "run" at the TTY.  */
+      args.from_tty = 0;
+      catch_exceptions (uiout, symbol_file_add_from_memory_wrapper,
+			&args, NULL, RETURN_MASK_ALL);
+    }
 }
 
 
@@ -143,4 +218,7 @@ Load the symbols out of memory from a dynamically loaded object file.\n\
 Give an expression for the address of the file's shared object file header.",
            &cmdlist);
 
+  /* Want to know of each new inferior so that its vsyscall info can
+     be extracted.  */
+  observer_attach_inferior_created (add_vsyscall_page);
 }