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, 18 insertions, 29 deletions

diff --git a/gdb/symmisc.c b/gdb/symmisc.c
index 86422e7..ed2e8d2 100644
--- a/gdb/symmisc.c
+++ b/gdb/symmisc.c
@@ -54,15 +54,8 @@ FILE *std_err;
 
 static int block_depth (struct block *);
 
-struct print_symbol_args
-  {
-    struct gdbarch *gdbarch;
-    struct symbol *symbol;
-    int depth;
-    struct ui_file *outfile;
-  };
-
-static int print_symbol (void *);
+static void print_symbol (struct gdbarch *gdbarch, struct symbol *symbol,
+			  int depth, ui_file *outfile);
 
 
 void
@@ -357,14 +350,16 @@ dump_symtab_1 (struct symtab *symtab, struct ui_file *outfile)
 	     block, not any blocks from included symtabs.  */
 	  ALL_DICT_SYMBOLS (BLOCK_DICT (b), iter, sym)
 	    {
-	      struct print_symbol_args s;
-
-	      s.gdbarch = gdbarch;
-	      s.symbol = sym;
-	      s.depth = depth + 1;
-	      s.outfile = outfile;
-	      catch_errors (print_symbol, &s, "Error printing symbol:\n",
-			    RETURN_MASK_ERROR);
+	      TRY
+		{
+		  print_symbol (gdbarch, sym, depth + 1, outfile);
+		}
+	      CATCH (ex, RETURN_MASK_ERROR)
+		{
+		  exception_fprintf (gdb_stderr, ex,
+				     "Error printing symbol:\n");
+		}
+	      END_CATCH
 	    }
 	}
       fprintf_filtered (outfile, "\n");
@@ -515,18 +510,12 @@ maintenance_print_symbols (const char *args, int from_tty)
     }
 }
 
-/* Print symbol ARGS->SYMBOL on ARGS->OUTFILE.  ARGS->DEPTH says how
-   far to indent.  ARGS is really a struct print_symbol_args *, but is
-   declared as char * to get it past catch_errors.  Returns 0 for error,
-   1 for success.  */
+/* Print symbol SYMBOL on OUTFILE.  DEPTH says how far to indent.  */
 
-static int
-print_symbol (void *args)
+static void
+print_symbol (struct gdbarch *gdbarch, struct symbol *symbol,
+	      int depth, ui_file *outfile)
 {
-  struct gdbarch *gdbarch = ((struct print_symbol_args *) args)->gdbarch;
-  struct symbol *symbol = ((struct print_symbol_args *) args)->symbol;
-  int depth = ((struct print_symbol_args *) args)->depth;
-  struct ui_file *outfile = ((struct print_symbol_args *) args)->outfile;
   struct obj_section *section;
 
   if (SYMBOL_OBJFILE_OWNED (symbol))
@@ -546,8 +535,9 @@ print_symbol (void *args)
 					    section->the_bfd_section));
       else
 	fprintf_filtered (outfile, "\n");
-      return 1;
+      return;
     }
+
   if (SYMBOL_DOMAIN (symbol) == STRUCT_DOMAIN)
     {
       if (TYPE_TAG_NAME (SYMBOL_TYPE (symbol)))
@@ -694,7 +684,6 @@ print_symbol (void *args)
 	}
     }
   fprintf_filtered (outfile, "\n");
-  return 1;
 }
 
 static void