2009-02-06 Pedro Alves <pedro@codesourcery.com>

	gdb/
	* target.h (enum target_object): Add new TARGET_OBJECT_SIGNAL_INFO.
	* infrun.c (siginfo_value_read, siginfo_value_write): New.
	(siginfo_value_funcs): New.
	(siginfo_make_value): New.
	(_initialize_infrun): Create the $_siginfo convenience variable.
	* gdbtypes.h (append_composite_type_field_aligned): Declare.
	* gdbtypes.c (append_composite_type_field): Rename to...
	(append_composite_type_field_aligned): ... this.  Add ALIGNMENT
	argument.  Handle it.
	(append_composite_type_field): Rewrite on top of
	append_composite_type_field_aligned.
	* value.h (internalvar_make_value): New typedef.
	(struct internalvar) <make_value>: New field.
	(create_internalvar_type_lazy): Declare.
	* value.c (create_internalvar): Clear make_value.
	(create_internalvar_type_lazy): New.
	(value_of_internalvar): If make_value is set use it.
	(preserve_values): Skip internal variables that don't have a
	value.
	* gdbarch.sh (get_siginfo_type): New.
	* gdbarch.h, gdbarch.c: Regenerate.

	* linux-tdep.h, linux-tdep.c: New.
	* amd64-linux-tdep.c: Include "linux-tdep.h".
	(amd64_linux_init_abi): Register linux_get_siginfo_type and
	linux_get_siginfo_mapper.
	* i386-linux-tdep.c: Include "linux-tdep.h".
	(i386_linux_init_abi): Register linux_get_siginfo_type and
	linux_get_siginfo_mapper.
	* arm-linux-tdep.c: Include "linux-tdep.h".
	(i386_linux_init_abi): Register linux_get_siginfo_type and
	linux_get_siginfo_mapper.

	* linux-nat.c (linux_xfer_siginfo): New.
	(linux_nat_xfer_partial): Handle TARGET_OBJECT_SIGNAL_INFO.
	* remote.c (PACKET_qXfer_siginfo_read)
	(PACKET_qXfer_siginfo_write): New.
	(feature remote_protocol_features): Add "qXfer:siginfo:read" and
	"qXfer:siginfo:write" features.
	(remote_xfer_partial): Handle TARGET_OBJECT_SIGNAL_INFO.
	(_initialize_remote): Add "set/show remote read-siginfo-object"
	and "set/show remote write-siginfo-object" commands.

	* Makefile.in (ALL_TARGET_OBS): Add linux-tdep.o.
	(HFILES_NO_SRCDIR): Add linux-tdep.h.
	(ALLDEPFILES): Add linux-tdep.c.

	* configure.tgt (arm*-*-linux* | arm*-*-uclinux*)
	(i[34567]86-*-linux*, x86_64-*-linux*): Add linux-tdep.o to
	gdb_target_obs.

2009-02-06  Pedro Alves  <pedro@codesourcery.com>

	gdb/gdbserver/
	* server.c (handle_query): Report qXfer:siginfo:read and
	qXfer:siginfo:write as supported and handle them.
	* target.h (struct target_ops) <qxfer_siginfo>: New field.
	* linux-low.c (linux_xfer_siginfo): New.
	(linux_target_ops): Set it.

2009-02-06  Pedro Alves  <pedro@codesourcery.com>

	gdb/doc/
	* gdb.texinfo (Signals): Document $_siginfo.
	(Convenience Variables): Mention $_siginfo.
	(Remote Configuration): Document qXfer:siginfo:read,
	qXfer:siginfo:write packets, and the read-siginfo-object,
	write-siginfo-object commands.

2009-02-06  Pedro Alves  <pedro@codesourcery.com>

	gdb/testsuite/
	* gdb.base/siginfo-obj.c, gdb.base/siginfo-obj.exp: New.

1 files changed, 87 insertions, 0 deletions

diff --git a/gdb/infrun.c b/gdb/infrun.c
index 3a67ac5..bed628d 100644
--- a/gdb/infrun.c
+++ b/gdb/infrun.c
@@ -4804,6 +4804,87 @@ signals_info (char *signum_exp, int from_tty)
 
   printf_filtered (_("\nUse the \"handle\" command to change these tables.\n"));
 }
+
+/* The $_siginfo convenience variable is a bit special.  We don't know
+   for sure the type of the value until we actually have a chance to
+   fetch the data.  The type can change depending on gdbarch, so it it
+   also dependent on which thread you have selected.
+
+     1. making $_siginfo be an internalvar that creates a new value on
+     access.
+
+     2. making the value of $_siginfo be an lval_computed value.  */
+
+/* This function implements the lval_computed support for reading a
+   $_siginfo value.  */
+
+static void
+siginfo_value_read (struct value *v)
+{
+  LONGEST transferred;
+
+  transferred =
+    target_read (&current_target, TARGET_OBJECT_SIGNAL_INFO,
+		 NULL,
+		 value_contents_all_raw (v),
+		 value_offset (v),
+		 TYPE_LENGTH (value_type (v)));
+
+  if (transferred != TYPE_LENGTH (value_type (v)))
+    error (_("Unable to read siginfo"));
+}
+
+/* This function implements the lval_computed support for writing a
+   $_siginfo value.  */
+
+static void
+siginfo_value_write (struct value *v, struct value *fromval)
+{
+  LONGEST transferred;
+
+  transferred = target_write (&current_target,
+			      TARGET_OBJECT_SIGNAL_INFO,
+			      NULL,
+			      value_contents_all_raw (fromval),
+			      value_offset (v),
+			      TYPE_LENGTH (value_type (fromval)));
+
+  if (transferred != TYPE_LENGTH (value_type (fromval)))
+    error (_("Unable to write siginfo"));
+}
+
+static struct lval_funcs siginfo_value_funcs =
+  {
+    siginfo_value_read,
+    siginfo_value_write
+  };
+
+/* Return a new value with the correct type for the siginfo object of
+   the current thread.  Return a void value if there's no object
+   available.  */
+
+struct value *
+siginfo_make_value (struct internalvar *var)
+{
+  struct type *type;
+  struct gdbarch *gdbarch;
+
+  if (target_has_stack
+      && !ptid_equal (inferior_ptid, null_ptid))
+    {
+      gdbarch = get_frame_arch (get_current_frame ());
+
+      if (gdbarch_get_siginfo_type_p (gdbarch))
+	{
+	  type = gdbarch_get_siginfo_type (gdbarch);
+
+	  return allocate_computed_value (type, &siginfo_value_funcs, NULL);
+	}
+    }
+
+  return allocate_value (builtin_type_void);
+}
+
 
 /* Inferior thread state.
    These are details related to the inferior itself, and don't include
@@ -5467,4 +5548,10 @@ Options are 'forward' or 'reverse'."),
 
   observer_attach_thread_ptid_changed (infrun_thread_ptid_changed);
   observer_attach_thread_stop_requested (infrun_thread_stop_requested);
+
+  /* Explicitly create without lookup, since that tries to create a
+     value with a void typed value, and when we get here, gdbarch
+     isn't initialized yet.  At this point, we're quite sure there
+     isn't another convenience variable of the same name.  */
+  create_internalvar_type_lazy ("_siginfo", siginfo_make_value);
 }