+
+/* 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 (¤t_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 (¤t_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. */
+
+static 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);
+}
+