Eliminate catch_errors

If you want to use catch_errors with a function with parameters, then
currently you have to manually write a "capture" struct wrapping the
arguments and marshall/unmarshall that.

https://sourceware.org/ml/gdb-patches/2017-09/msg00834.html proposed
adjusting catch_errors to use gdb::function_view, which would allow
passing lambdas with automatic captures.  However, it seems like using
TRY/CATCH directly instead ends up producing clearer and easier to
debug code.  This is what this commit does.

Note that removing catch_errors exposes further cleanup opportunities
around no longer having to follow catch_errors callback type, and also
removes a few cleanups.

I didn't do anything to save/restore current_uiout because I think
that should be the responsibility of the code that changes
current_uiout in the first place.

(Another approach could be to make catch_errors a variadic template
like:

  template<typename Function, typename... Args>
  int catch_errors (const char *errstring, return_mask mask,
		    Function &&func, Args... args);

and then with:

  extern void function_with_args (int, int);
  extern void function_with_no_args ();

calls to the above functions would be wrapped like this:

  catch_errors ("some error happened", RETURN_MASK_ERROR,
                function_with_args, arg1, arg2);

  catch_errors ("some error happened", RETURN_MASK_ERROR,
                function_with_no_args);

but I'm thinking that that doesn't improve much if at all either.)

gdb/ChangeLog
2017-10-10  Pedro Alves  <palves@redhat.com>
	    Tom Tromey  <tom@tromey.com>

	* breakpoint.c (breakpoint_cond_eval): Change return type to bool
	and reverse logic.
	(WP_DELETED, WP_VALUE_CHANGED, WP_VALUE_NOT_CHANGED, WP_IGNORE):
	No longer macros.  Instead ...
	(enum wp_check_result): They're now values of this new
	enumeration.
	(watchpoint_check): Change return type to wp_check_result and
	parameter type to bpstat.
	(bpstat_check_watchpoint): Use TRY/CATCH instead of catch_errors.
	(bpstat_check_breakpoint_conditions): Use TRY/CATCH instead of
	catch_errors.  Reverse logic of watchpoint_check call.
	(breakpoint_re_set_one): Now returns void and takes a breakpoint
	pointer as parameter.
	(breakpoint_re_set): Use TRY/CATCH instead of catch_errors.
	* common/common-exceptions.c (throw_exception_sjlj): Update
	comments to avoid mentioning catch_errors.
	* exceptions.c (catch_errors): Delete.
	* exceptions.h: Update comments to avoid mentioning catch_errors.
	(catch_errors_ftype, catch_errors): Delete.
	* infrun.c (normal_stop): Use TRY/CATCH instead of catch_errors.
	(hook_stop_stub): Delete.
	(restore_selected_frame): Change return type to void, and
	parameter type to const frame_id &.
	(restore_infcall_control_state): Use TRY/CATCH instead of
	catch_errors.
	* main.c (captured_command_loop): Return void and remove
	parameter.  Remove references to catch_errors.
	(captured_main): Use TRY/CATCH instead of catch_errors.
	* objc-lang.c (objc_submethod_helper_data)
	(find_objc_msgcall_submethod_helper): Delete.
	(find_objc_msgcall_submethod): Use TRY/CATCH instead of
	catch_errors.
	* record-full.c (record_full_message): Return void.
	(record_full_message_args, record_full_message_wrapper): Delete.
	(record_full_message_wrapper_safe): Return bool and use TRY/CATCH
	instead of catch_errors.
	* solib-aix.c (solib_aix_open_symbol_file_object): Change
	parameter type to int.
	* solib-darwin.c (open_symbol_file_object): Ditto.
	* solib-dsbt.c (open_symbol_file_object): Ditto.
	* solib-frv.c (open_symbol_file_object): Ditto.
	* solib-svr4.c (open_symbol_file_object): Ditto.
	* solib-target.c (solib_target_open_symbol_file_object): Ditto.
	* solib.c (update_solib_list): Use TRY/CATCH instead of
	catch_errors.
	* solist.h (struct target_so_ops) <open_symbol_file_object>:
	Change type.
	* symmisc.c (struct print_symbol_args): Remove.
	(dump_symtab_1): Use TRY/CATCH instead of catch_errors.
	(print_symbol): Change type.
	* windows-nat.c (handle_load_dll, handle_unload_dll): Return void
	and remove parameters.
	(catch_errors): New.
	(get_windows_debug_event): Adjust.

gdb/testsuite/ChangeLog:
2017-10-10  Pedro Alves  <palves@redhat.com>

	* lib/selftest-support.exp (selftest_setup): Update for
	captured_command_loop's prototype change.

1 files changed, 7 insertions, 25 deletions

diff --git a/gdb/exceptions.h b/gdb/exceptions.h
index b2cdee3..37b8a19 100644
--- a/gdb/exceptions.h
+++ b/gdb/exceptions.h
@@ -48,21 +48,16 @@ extern void exception_fprintf (struct ui_file *file, struct gdb_exception e,
    copy of the gdb error message.  This is used when a silent error is 
    issued and the caller wants to manually issue the error message.
 
-   MASK specifies what to catch; it is normally set to
-   RETURN_MASK_ALL, if for no other reason than that the code which
-   calls catch_errors might not be set up to deal with a quit which
-   isn't caught.  But if the code can deal with it, it generally
-   should be RETURN_MASK_ERROR, unless for some reason it is more
-   useful to abort only the portion of the operation inside the
-   catch_errors.  Note that quit should return to the command line
+   MASK specifies what to catch; it is normally set to RETURN_MASK_ALL
+   if the code which calls catch_exceptions is not set up to deal with
+   a quit which isn't caught.  But if the code can deal with it, it
+   generally should be RETURN_MASK_ERROR, unless for some reason it is
+   more useful to abort only the portion of the operation inside the
+   catch_exceptions.  Note that quit should return to the command line
    fairly quickly, even if some further processing is being done.
 
    FIXME; cagney/2001-08-13: The need to override the global UIOUT
-   builder variable should just go away.
-
-   This function supersedes catch_errors().
-
-   This function uses SETJMP() and LONGJUMP().  */
+   builder variable should just go away.  */
 
 struct ui_out;
 typedef int (catch_exceptions_ftype) (struct ui_out *ui_out, void *args);
@@ -76,19 +71,6 @@ extern int catch_exceptions_with_msg (struct ui_out *uiout,
 			     	      char **gdberrmsg,
 				      return_mask mask);
 
-/* If CATCH_ERRORS_FTYPE throws an error, catch_errors() returns zero
-   otherwize the result from CATCH_ERRORS_FTYPE is returned.  It is
-   probably useful for CATCH_ERRORS_FTYPE to always return a non-zero
-   value.  It's unfortunate that, catch_errors() does not return an
-   indication of the exact exception that it caught - quit_flag might
-   help.
-
-   This function is superseded by catch_exceptions().  */
-
-typedef int (catch_errors_ftype) (void *);
-extern int catch_errors (catch_errors_ftype *, void *,
-			 const char *, return_mask);
-
 /* Compare two exception objects for print equality.  */
 extern int exception_print_same (struct gdb_exception e1,
 				 struct gdb_exception e2);