Implement 'set print frame-info|frame-arguments presence'.

New settings allow to better control what frame information is printed.

'set print frame-info' allows to override the default frame information
printed when a GDB command prints a frame.
The backtrace command has a new option -frame-info to override
this global setting.

It is now possible to have very short frame information by using the
new 'set print frame-arguments presence' and
'set print frame-info short-location'.

Combined with 'set print address off', a backtrace will only show
the essential information to see the function call chain, e.g.:
  (gdb) set print address off
  (gdb) set print frame-arguments presence
  (gdb) set print frame-info short-location
  (gdb) bt
  #0  break_me ()
  #1  call_me (...)
  #2  main ()
  (gdb)

This is handy in particular for big backtraces with functions having
many arguments.

Python frame filter printing logic has been updated to respect the new
setting in non MI mode.

Also, the default frame information printed was inconsistent when
backtrace was printing the frame information itself, or when the python
frame filtering code was printing the frame information.
This patch changes the default of python frame filtering to have a
consistent behaviour regarding printed frame-information, whatever
the presence/activity/matches of python filters.

2019-07-29  Philippe Waroquiers  <philippe.waroquiers@skynet.be>

	* frame.h (enum print_what): New value 'SHORT_LOCATION', update
	comments.
	(print_frame_info_auto, print_frame_info_source_line,
	print_frame_info_location, print_frame_info_source_and_location,
	print_frame_info_location_and_address, print_frame_info_short_location):
	New declarations.
	(struct frame_print_options): New member print_frame_info.
	* extension.h (enum ext_lang_frame_args): New value CLI_PRESENCE.
	* stack.h (get_user_print_what_frame_info): New declaration.
	(frame_show_address): New declaration.
	* stack.c (print_frame_arguments_choices): New value 'presence'.
	(print_frame_info_auto, print_frame_info_source_line,
	print_frame_info_location, print_frame_info_source_and_location,
	print_frame_info_location_and_address, print_frame_info_short_location,
	print_frame_info_choices, print_frame_info_print_what): New definitions.
	(print_frame_args): Only print dots for args if print frame-arguments
	is 'presence'.
	(frame_print_option_defs): New element for "frame-info".
	(get_user_print_what_frame_info): New function.
	(frame_show_address): Make non static.  Move comment to stack.h.
	(print_frame_info_to_print_what): New function.
	(print_frame_info): Update comment.  Use fp_opts.print_frame_info
	to decide what to print.
	(backtrace_command_1): Handle the new print_frame_arguments_presence
	value.
	(_initialize_stack): Call add_setshow_enum_cmd for frame-info.
	* python/py-framefilter.c (py_print_args): Handle CLI_PRESENCE.
	(py_print_frame): In non-mi mode, use LOCATION as default for
	print_what, similarly to frame information printed directly by
	backtrace command. Handle frame-info user option in non MI mode.

1 files changed, 108 insertions, 18 deletions

diff --git a/gdb/stack.c b/gdb/stack.c
index 06f10a1..7833ca4 100644
--- a/gdb/stack.c
+++ b/gdb/stack.c
@@ -61,15 +61,44 @@
 const char print_frame_arguments_all[] = "all";
 const char print_frame_arguments_scalars[] = "scalars";
 const char print_frame_arguments_none[] = "none";
+const char print_frame_arguments_presence[] = "presence";
 
 static const char *const print_frame_arguments_choices[] =
 {
   print_frame_arguments_all,
   print_frame_arguments_scalars,
   print_frame_arguments_none,
+  print_frame_arguments_presence,
   NULL
 };
 
+/* The possible choices of "set print frame-info", and the value
+   of this setting.  */
+
+const char print_frame_info_auto[] = "auto";
+const char print_frame_info_source_line[] = "source-line";
+const char print_frame_info_location[] = "location";
+const char print_frame_info_source_and_location[] = "source-and-location";
+const char print_frame_info_location_and_address[] = "location-and-address";
+const char print_frame_info_short_location[] = "short-location";
+
+static const char *const print_frame_info_choices[] =
+{
+  print_frame_info_auto,
+  print_frame_info_source_line,
+  print_frame_info_location,
+  print_frame_info_source_and_location,
+  print_frame_info_location_and_address,
+  print_frame_info_short_location,
+  NULL
+};
+
+/* print_frame_info_print_what[i] maps a choice to the corresponding
+   print_what enum.  */
+static const gdb::optional<enum print_what> print_frame_info_print_what[] =
+  {{}, /* Empty value for "auto".  */
+   SRC_LINE, LOCATION, SRC_AND_LOC, LOC_AND_ADDRESS, SHORT_LOCATION};
+
 /* The possible choices of "set print entry-values", and the value
    of this setting.  */
 
@@ -137,6 +166,17 @@ or both.  Note that one or both of these values may be <optimized out>."),
     N_("If set, frame arguments are printed in raw form, bypassing any\n\
 pretty-printers for that value.")
   },
+
+  enum_option_def {
+    "frame-info",
+    print_frame_info_choices,
+    [] (frame_print_options *opt) { return &opt->print_frame_info; },
+    NULL, /* show_cmd_cb */
+    N_("Set printing of frame information."),
+    N_("Show printing of frame information."),
+    NULL /* help_doc */
+  }
+
 };
 
 /* Options for the "backtrace" command.  */
@@ -209,10 +249,9 @@ static struct symtab *last_displayed_symtab = 0;
 static int last_displayed_line = 0;
 
 
-/* Return 1 if we should display the address in addition to the location,
-   because we are in the middle of a statement.  */
+/* See stack.h.  */
 
-static int
+int
 frame_show_address (struct frame_info *frame,
 		    struct symtab_and_line sal)
 {
@@ -631,9 +670,14 @@ print_frame_args (const frame_print_options &fp_opts,
   long highest_offset = -1;
   /* Number of ints of arguments that we have printed so far.  */
   int args_printed = 0;
+  /* True if we should print arg names.  If false, we only indicate
+     the presence of arguments by printing ellipsis.  */
+  bool print_names
+    = fp_opts.print_frame_arguments != print_frame_arguments_presence;
   /* True if we should print arguments, false otherwise.  */
   bool print_args
-    = fp_opts.print_frame_arguments != print_frame_arguments_none;
+    = (print_names
+       && fp_opts.print_frame_arguments != print_frame_arguments_none);
 
   if (func)
     {
@@ -653,6 +697,13 @@ print_frame_args (const frame_print_options &fp_opts,
 	  if (!SYMBOL_IS_ARGUMENT (sym))
 	    continue;
 
+	  if (!print_names)
+	    {
+	      uiout->text ("...");
+	      first = 0;
+	      break;
+	    }
+
 	  switch (SYMBOL_CLASS (sym))
 	    {
 	    case LOC_ARG:
@@ -801,8 +852,11 @@ print_frame_args (const frame_print_options &fp_opts,
       else
 	start = highest_offset;
 
-      print_frame_nameless_args (frame, start, num - args_printed,
-				 first, stream);
+      if (!print_names && !first && num > 0)
+	uiout->text ("...");
+      else
+	print_frame_nameless_args (frame, start, num - args_printed,
+				   first, stream);
     }
 }
 
@@ -859,13 +913,37 @@ do_gdb_disassembly (struct gdbarch *gdbarch,
     }
 }
 
+/* Converts the PRINT_FRAME_INFO choice to an optional enum print_what.
+   Value not present indicates to the caller to use default values
+   specific to the command being executed.  */
+
+static gdb::optional<enum print_what>
+print_frame_info_to_print_what (const char *print_frame_info)
+{
+  for (int i = 0; print_frame_info_choices[i] != NULL; i++)
+    if (print_frame_info == print_frame_info_choices[i])
+      return print_frame_info_print_what[i];
+
+  internal_error (__FILE__, __LINE__,
+		  "Unexpected print frame-info value `%s'.",
+		  print_frame_info);
+}
+
+/* See stack.h.  */
+
+void
+get_user_print_what_frame_info (gdb::optional<enum print_what> *what)
+{
+  *what
+    = print_frame_info_to_print_what
+        (user_frame_print_options.print_frame_info);
+}
+
 /* Print information about frame FRAME.  The output is format according
-   to PRINT_LEVEL and PRINT_WHAT and PRINT_ARGS.  The meaning of
-   PRINT_WHAT is:
-   
-   SRC_LINE: Print only source line.
-   LOCATION: Print only location.
-   SRC_AND_LOC: Print location and source line.
+   to PRINT_LEVEL and PRINT_WHAT and PRINT_ARGS.  For the meaning of
+   PRINT_WHAT, see enum print_what comments in frame.h.
+   Note that PRINT_WHAT is overriden if FP_OPTS.print_frame_info
+   != print_frame_info_auto.
 
    Used in "where" output, and to emit breakpoint or step
    messages.  */
@@ -881,6 +959,13 @@ print_frame_info (const frame_print_options &fp_opts,
   int location_print;
   struct ui_out *uiout = current_uiout;
 
+  if (!current_uiout->is_mi_like_p ()
+      && fp_opts.print_frame_info != print_frame_info_auto)
+    {
+      /* Use the specific frame information desired by the user.  */
+      print_what = *print_frame_info_to_print_what (fp_opts.print_frame_info);
+    }
+
   if (get_frame_type (frame) == DUMMY_FRAME
       || get_frame_type (frame) == SIGTRAMP_FRAME
       || get_frame_type (frame) == ARCH_FRAME)
@@ -944,10 +1029,10 @@ print_frame_info (const frame_print_options &fp_opts,
      to get the line containing FRAME->pc.  */
   symtab_and_line sal = find_frame_sal (frame);
 
-  location_print = (print_what == LOCATION 
+  location_print = (print_what == LOCATION
+		    || print_what == SRC_AND_LOC
 		    || print_what == LOC_AND_ADDRESS
-		    || print_what == SRC_AND_LOC);
-
+		    || print_what == SHORT_LOCATION);
   if (location_print || !sal.symtab)
     print_frame (fp_opts, frame, print_level, print_what, print_args, sal);
 
@@ -1258,7 +1343,7 @@ print_frame (const frame_print_options &fp_opts,
 	QUIT;
       }
     uiout->text (")");
-    if (sal.symtab)
+    if (print_what != SHORT_LOCATION && sal.symtab)
       {
 	const char *filename_display;
       
@@ -1281,7 +1366,8 @@ print_frame (const frame_print_options &fp_opts,
 	annotate_frame_source_end ();
       }
 
-    if (pc_p && (funname == NULL || sal.symtab == NULL))
+    if (print_what != SHORT_LOCATION
+	&& pc_p && (funname == NULL || sal.symtab == NULL))
       {
 	char *lib = solib_name_from_address (get_frame_program_space (frame),
 					     get_frame_pc (frame));
@@ -1891,8 +1977,12 @@ backtrace_command_1 (const frame_print_options &fp_opts,
 	arg_type = CLI_SCALAR_VALUES;
       else if (fp_opts.print_frame_arguments == print_frame_arguments_all)
 	arg_type = CLI_ALL_VALUES;
-      else
+      else if (fp_opts.print_frame_arguments == print_frame_arguments_presence)
+	arg_type = CLI_PRESENCE;
+      else if (fp_opts.print_frame_arguments == print_frame_arguments_none)
 	arg_type = NO_VALUES;
+      else
+	gdb_assert (0);
 
       result = apply_ext_lang_frame_filter (get_current_frame (), flags,
 					    arg_type, current_uiout,