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, 24 insertions, 11 deletions

diff --git a/gdb/windows-nat.c b/gdb/windows-nat.c
index 98c32d8..58d7e11 100644
--- a/gdb/windows-nat.c
+++ b/gdb/windows-nat.c
@@ -756,8 +756,8 @@ get_image_name (HANDLE h, void *address, int unicode)
    do_initial_windows_stuff and windows_add_all_dlls for more info
    on how we handle DLL loading during that phase).  */
 
-static int
-handle_load_dll (void *dummy)
+static void
+handle_load_dll ()
 {
   LOAD_DLL_DEBUG_INFO *event = &current_event.u.LoadDll;
   char *dll_name;
@@ -770,7 +770,7 @@ handle_load_dll (void *dummy)
   dll_name = get_image_name (current_process_handle,
 			     event->lpImageName, event->fUnicode);
   if (!dll_name)
-    return 1;
+    return;
 
   solib_end->next = windows_make_so (dll_name, event->lpBaseOfDll);
   solib_end = solib_end->next;
@@ -779,8 +779,6 @@ handle_load_dll (void *dummy)
 
   DEBUG_EVENTS (("gdb: Loading dll \"%s\" at %s.\n", solib_end->so_name,
 		 host_address_to_string (li->load_addr)));
-
-  return 1;
 }
 
 static void
@@ -800,8 +798,8 @@ windows_free_so (struct so_list *so)
    do_initial_windows_stuff and windows_add_all_dlls for more info
    on how we handle DLL loading during that phase).  */
 
-static int
-handle_unload_dll (void *dummy)
+static void
+handle_unload_dll ()
 {
   LPVOID lpBaseOfDll = current_event.u.UnloadDll.lpBaseOfDll;
   struct so_list *so;
@@ -820,7 +818,7 @@ handle_unload_dll (void *dummy)
 	  DEBUG_EVENTS (("gdb: Unloading dll \"%s\".\n", sodel->so_name));
 
 	  windows_free_so (sodel);
-	  return 1;
+	  return;
 	}
     }
 
@@ -833,8 +831,23 @@ handle_unload_dll (void *dummy)
      32bit and 64bit worlds).  */
   complaint (&symfile_complaints, _("dll starting at %s not found."),
 	     host_address_to_string (lpBaseOfDll));
+}
 
-  return 0;
+/* Call FUNC wrapped in a TRY/CATCH that swallows all GDB
+   exceptions.  */
+
+static void
+catch_errors (void (*func) ())
+{
+  TRY
+    {
+      func ();
+    }
+  CATCH (ex, RETURN_MASK_ALL)
+    {
+      exception_print (gdb_stderr, ex);
+    }
+  END_CATCH
 }
 
 /* Clear list of loaded DLLs.  */
@@ -1542,7 +1555,7 @@ get_windows_debug_event (struct target_ops *ops,
       CloseHandle (current_event.u.LoadDll.hFile);
       if (saw_create != 1 || ! windows_initialization_done)
 	break;
-      catch_errors (handle_load_dll, NULL, (char *) "", RETURN_MASK_ALL);
+      catch_errors (handle_load_dll);
       ourstatus->kind = TARGET_WAITKIND_LOADED;
       ourstatus->value.integer = 0;
       thread_id = main_thread_id;
@@ -1555,7 +1568,7 @@ get_windows_debug_event (struct target_ops *ops,
 		     "UNLOAD_DLL_DEBUG_EVENT"));
       if (saw_create != 1 || ! windows_initialization_done)
 	break;
-      catch_errors (handle_unload_dll, NULL, (char *) "", RETURN_MASK_ALL);
+      catch_errors (handle_unload_dll);
       ourstatus->kind = TARGET_WAITKIND_LOADED;
       ourstatus->value.integer = 0;
       thread_id = main_thread_id;