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, 78 insertions, 12 deletions

diff --git a/gdb/python/py-framefilter.c b/gdb/python/py-framefilter.c
index 840faf9..a2a96ac 100644
--- a/gdb/python/py-framefilter.c
+++ b/gdb/python/py-framefilter.c
@@ -25,6 +25,8 @@
 #include "python.h"
 #include "ui-out.h"
 #include "valprint.h"
+#include "stack.h"
+#include "source.h"
 #include "annotate.h"
 #include "hashtab.h"
 #include "demangle.h"
@@ -713,9 +715,21 @@ py_print_args (PyObject *filter,
   annotate_frame_args ();
   out->text (" (");
 
-  if (args_iter != Py_None
-      && (enumerate_args (args_iter.get (), out, args_type, 0, frame)
-	  == EXT_LANG_BT_ERROR))
+  if (args_type == CLI_PRESENCE)
+    {
+      if (args_iter != Py_None)
+	{
+	  gdbpy_ref<> item (PyIter_Next (args_iter.get ()));
+
+	  if (item != NULL)
+	    out->text ("...");
+	  else if (PyErr_Occurred ())
+	    return EXT_LANG_BT_ERROR;
+	}
+    }
+  else if (args_iter != Py_None
+	   && (enumerate_args (args_iter.get (), out, args_type, 0, frame)
+	       == EXT_LANG_BT_ERROR))
     return EXT_LANG_BT_ERROR;
 
   out->text (")");
@@ -748,7 +762,16 @@ py_print_frame (PyObject *filter, frame_filter_flags flags,
   struct gdbarch *gdbarch = NULL;
   struct frame_info *frame = NULL;
   struct value_print_options opts;
+
   int print_level, print_frame_info, print_args, print_locals;
+  /* Note that the below default in non-mi mode is the same as the
+     default value for the backtrace command (see the call to print_frame_info
+     in backtrace_command_1).
+     Having the same default ensures that 'bt' and 'bt no-filters'
+     have the same behaviour when some filters exist but do not apply
+     to a frame.  */
+  enum print_what print_what
+    = out->is_mi_like_p () ? LOC_AND_ADDRESS : LOCATION;
   gdb::unique_xmalloc_ptr<char> function_to_free;
 
   /* Extract print settings from FLAGS.  */
@@ -758,6 +781,17 @@ py_print_frame (PyObject *filter, frame_filter_flags flags,
   print_locals = (flags & PRINT_LOCALS) ? 1 : 0;
 
   get_user_print_options (&opts);
+  if (print_frame_info)
+  {
+    gdb::optional<enum print_what> user_frame_info_print_what;
+
+    get_user_print_what_frame_info (&user_frame_info_print_what);
+    if (!out->is_mi_like_p () && user_frame_info_print_what.has_value ())
+      {
+	/* Use the specific frame information desired by the user.  */
+	print_what = *user_frame_info_print_what;
+      }
+  }
 
   /* Get the underlying frame.  This is needed to determine GDB
   architecture, and also, in the cases of frame variables/arguments to
@@ -771,6 +805,8 @@ py_print_frame (PyObject *filter, frame_filter_flags flags,
   if (frame == NULL)
     return EXT_LANG_BT_ERROR;
 
+  symtab_and_line sal = find_frame_sal (frame);
+
   gdbarch = get_frame_arch (frame);
 
   /* stack-list-variables.  */
@@ -815,9 +851,19 @@ py_print_frame (PyObject *filter, frame_filter_flags flags,
 	}
     }
 
+  /* For MI, each piece is controlled individually.  */
+  bool location_print = (print_frame_info
+			 && !out->is_mi_like_p ()
+			 && (print_what == LOCATION
+			     || print_what == SRC_AND_LOC
+			     || print_what == LOC_AND_ADDRESS
+			     || print_what == SHORT_LOCATION));
+
   /* Print frame level.  MI does not require the level if
      locals/variables only are being printed.  */
-  if ((print_frame_info || print_args) && print_level)
+  if (print_level
+      && (location_print
+	  || (out->is_mi_like_p () && (print_frame_info || print_args))))
     {
       struct frame_info **slot;
       int level;
@@ -843,16 +889,21 @@ py_print_frame (PyObject *filter, frame_filter_flags flags,
 	}
     }
 
-  if (print_frame_info)
+  if (location_print || (out->is_mi_like_p () && print_frame_info))
     {
       /* Print address to the address field.  If an address is not provided,
 	 print nothing.  */
       if (opts.addressprint && has_addr)
 	{
-	  annotate_frame_address ();
-	  out->field_core_addr ("addr", gdbarch, address);
-	  annotate_frame_address_end ();
-	  out->text (" in ");
+	  if (!sal.symtab
+	      || frame_show_address (frame, sal)
+	      || print_what == LOC_AND_ADDRESS)
+	    {
+	      annotate_frame_address ();
+	      out->field_core_addr ("addr", gdbarch, address);
+	      annotate_frame_address_end ();
+	      out->text (" in ");
+	    }
 	}
 
       /* Print frame function name.  */
@@ -904,14 +955,17 @@ py_print_frame (PyObject *filter, frame_filter_flags flags,
 
   /* Frame arguments.  Check the result, and error if something went
      wrong.  */
-  if (print_args)
+  if (print_args && (location_print || out->is_mi_like_p ()))
     {
       if (py_print_args (filter, out, args_type, frame) == EXT_LANG_BT_ERROR)
 	return EXT_LANG_BT_ERROR;
     }
 
   /* File name/source/line number information.  */
-  if (print_frame_info)
+  bool print_location_source
+    = ((location_print && print_what != SHORT_LOCATION)
+       || (out->is_mi_like_p () && print_frame_info));
+  if (print_location_source)
     {
       annotate_frame_source_begin ();
 
@@ -963,12 +1017,24 @@ py_print_frame (PyObject *filter, frame_filter_flags flags,
                            (gdbarch_bfd_arch_info (gdbarch))->printable_name);
     }
 
+  bool source_print
+    = (! out->is_mi_like_p ()
+       && (print_what == SRC_LINE || print_what == SRC_AND_LOC));
+  if (source_print)
+    {
+      if (print_location_source)
+	out->text ("\n"); /* Newline after the location source.  */
+      print_source_lines (sal.symtab, sal.line, sal.line + 1, 0);
+    }
+
   /* For MI we need to deal with the "children" list population of
      elided frames, so if MI output detected do not send newline.  */
   if (! out->is_mi_like_p ())
     {
       annotate_frame_end ();
-      out->text ("\n");
+      /* print_source_lines has already printed a newline.  */
+      if (!source_print)
+	out->text ("\n");
     }
 
   if (print_locals)