Limit breakpoint re-set to the current program space

Currently, we always re-set all locations of all breakpoints.  This
commit makes us re-set only locations of the current program space.

If we loaded symbols to a program space (e.g., "file" command or some
shared library was loaded), GDB must run through all breakpoints and
determine if any new locations need to be added to the breakpoint.
However, there's no reason to recreate locations for _other_ program
spaces, as those haven't changed.

Similarly, when we create a new inferior, through e.g., a fork, GDB
must run through all breakpoints and determine if any new locations
need to be added to the breakpoint.  There's no reason to destroy the
locations of the parent inferior and other inferiors.  We know those
won't change.

In addition to being inneficient, resetting breakpoints of inferiors
that are currently running is problematic, because:

 - some targets can't read memory while the inferior is running.

 - the inferior might exit while we're re-setting its breakpoints,
   which may confuse prologue skipping.

I went through all the places where we call breakpoint_re_set, and it
seems to me that all can be changed to only re-set locations of the
current program space.

The patch that reversed threads order in "info threads" etc. happened
to make gdb.threads/fork-plus-thread.exp expose this problem when
testing on x86/-m32.  The problem was latent and masked out by chance
by the code-cache:

 https://sourceware.org/ml/gdb-patches/2016-01/msg00213.html

Tested on x86-64 F20, native (-m64/-m32) and extended-remote
gdbserver.

Fixes the regression discussed in the url above with --target_board=unix/-m32:

 -FAIL: gdb.threads/fork-plus-threads.exp: detach-on-fork=off: inferior 1 exited
 +PASS: gdb.threads/fork-plus-threads.exp: detach-on-fork=off: inferior 1 exited
 -FAIL: gdb.threads/fork-plus-threads.exp: detach-on-fork=off: no threads left (timeout)
 -FAIL: gdb.threads/fork-plus-threads.exp: detach-on-fork=off: only inferior 1 left (the program exited)
 +PASS: gdb.threads/fork-plus-threads.exp: detach-on-fork=off: no threads left
 +PASS: gdb.threads/fork-plus-threads.exp: detach-on-fork=off: only inferior 1 left

gdb/ChangeLog:
2016-01-19  Pedro Alves  <palves@redhat.com>

	* ax-gdb.c (agent_command_1): Adjust call to decode_line_full.
	* break-catch-throw.c (re_set_exception_catchpoint): Pass the
	current program space down to linespec decoding and breakpoint
	location updating.
	* breakpoint.c (parse_breakpoint_sals): Adjust calls to
	decode_line_full.
	(until_break_command): Adjust calls to decode_line_1.
	(base_breakpoint_decode_location, bkpt_decode_location): Add
	'search_pspace' parameter.  Pass it along.
	(bkpt_probe_create_sals_from_location): Adjust calls to
	parse_probes.
	(tracepoint_decode_location, tracepoint_probe_decode_location)
	(strace_marker_decode_location): Add 'search_pspace' parameter.
	Pass it along.
	(all_locations_are_pending): Rewrite to take a breakpoint and
	program space as arguments instead.
	(hoist_existing_locations): New function.
	(update_breakpoint_locations): Add 'filter_pspace' parameter.  Use
	hoist_existing_locations instead of always removing all locations,
	and adjust to all_locations_are_pending change.
	(location_to_sals): Add 'search_pspace' parameter.  Pass it along.
	Don't disable the breakpoint if there are other locations in
	another program space.
	(breakpoint_re_set_default): Adjust to pass down the current
	program space as filter program space.
	(decode_location_default): Add 'search_pspace' parameter and pass
	it along.
	(prepare_re_set_context): Don't switch program space here.
	(breakpoint_re_set): Use save_current_space_and_thread instead of
	save_current_program_space.
	* breakpoint.h (struct breakpoint_ops) <decode_location>: Add
	'search_pspace' parameter.
	(update_breakpoint_locations): Add 'filter_pspace' parameter.
	* cli/cli-cmds.c (edit_command, list_command): Adjust calls to
	decode_line_1.
	* elfread.c (elf_gnu_ifunc_resolver_return_stop): Pass the current
	program space as filter program space.
	* linespec.c (struct linespec_state) <search_pspace>: New field.
	(create_sals_line_offset, convert_explicit_location_to_sals)
	(parse_linespec): Pass the search program space down.
	(linespec_state_constructor): Add 'search_pspace' parameter.
	Store it.
	(linespec_parser_new): Add 'search_pspace' parameter and pass it
	along.
	(linespec_lex_to_end): Adjust.
	(decode_line_full, decode_line_1): Add 'search_pspace' parameter
	and pass it along.
	(decode_line_with_last_displayed): Adjust.
	(collect_symtabs_from_filename, symtabs_from_filename): New
	'search_pspace' parameter.  Use it.
	(find_function_symbols): Pass the search program space down.
	* linespec.h (decode_line_1, decode_line_full): Add
	'search_pspace' parameter.
	* probe.c (parse_probes_in_pspace): New function, factored out
	from ...
	(parse_probes): ... this.  Add 'search_pspace' parameter and use
	it.
	* probe.h (parse_probes): Add pspace' parameter.
	* python/python.c (gdbpy_decode_line): Adjust.
	* tracepoint.c (scope_info): Adjust.

1 files changed, 57 insertions, 25 deletions

diff --git a/gdb/linespec.c b/gdb/linespec.c
index 50951bd..588ad83 100644
--- a/gdb/linespec.c
+++ b/gdb/linespec.c
@@ -123,6 +123,10 @@ struct linespec_state
   /* The program space as seen when the module was entered.  */
   struct program_space *program_space;
 
+  /* If not NULL, the search is restricted to just this program
+     space.  */
+  struct program_space *search_pspace;
+
   /* The default symtab to use, if no other symtab is specified.  */
   struct symtab *default_symtab;
 
@@ -274,7 +278,8 @@ static struct symtabs_and_lines decode_objc (struct linespec_state *self,
 					     linespec_p ls,
 					     const char *arg);
 
-static VEC (symtab_ptr) *symtabs_from_filename (const char *);
+static VEC (symtab_ptr) *symtabs_from_filename (const char *,
+						struct program_space *pspace);
 
 static VEC (symbolp) *find_label_symbols (struct linespec_state *self,
 					  VEC (symbolp) *function_symbols,
@@ -302,7 +307,9 @@ static void add_all_symbol_names_from_pspace (struct collect_info *info,
 					      struct program_space *pspace,
 					      VEC (const_char_ptr) *names);
 
-static VEC (symtab_ptr) *collect_symtabs_from_filename (const char *file);
+static VEC (symtab_ptr) *
+  collect_symtabs_from_filename (const char *file,
+				 struct program_space *pspace);
 
 static void decode_digits_ordinary (struct linespec_state *self,
 				    linespec_p ls,
@@ -1842,7 +1849,8 @@ create_sals_line_offset (struct linespec_state *self,
       fullname = symtab_to_fullname (self->default_symtab);
       VEC_pop (symtab_ptr, ls->file_symtabs);
       VEC_free (symtab_ptr, ls->file_symtabs);
-      ls->file_symtabs = collect_symtabs_from_filename (fullname);
+      ls->file_symtabs = collect_symtabs_from_filename (fullname,
+							self->search_pspace);
       use_default = 1;
     }
 
@@ -2094,7 +2102,8 @@ convert_explicit_location_to_sals (struct linespec_state *self,
       TRY
 	{
 	  result->file_symtabs
-	    = symtabs_from_filename (explicit_loc->source_filename);
+	    = symtabs_from_filename (explicit_loc->source_filename,
+				     self->search_pspace);
 	}
       CATCH (except, RETURN_MASK_ERROR)
 	{
@@ -2285,7 +2294,8 @@ parse_linespec (linespec_parser *parser, const char *arg)
       TRY
 	{
 	  PARSER_RESULT (parser)->file_symtabs
-	    = symtabs_from_filename (user_filename);
+	    = symtabs_from_filename (user_filename,
+				     PARSER_STATE (parser)->search_pspace);
 	}
       CATCH (ex, RETURN_MASK_ERROR)
 	{
@@ -2367,6 +2377,7 @@ parse_linespec (linespec_parser *parser, const char *arg)
 static void
 linespec_state_constructor (struct linespec_state *self,
 			    int flags, const struct language_defn *language,
+			    struct program_space *search_pspace,
 			    struct symtab *default_symtab,
 			    int default_line,
 			    struct linespec_result *canonical)
@@ -2375,6 +2386,7 @@ linespec_state_constructor (struct linespec_state *self,
   self->language = language;
   self->funfirstline = (flags & DECODE_LINE_FUNFIRSTLINE) ? 1 : 0;
   self->list_mode = (flags & DECODE_LINE_LIST_MODE) ? 1 : 0;
+  self->search_pspace = search_pspace;
   self->default_symtab = default_symtab;
   self->default_line = default_line;
   self->canonical = canonical;
@@ -2389,6 +2401,7 @@ linespec_state_constructor (struct linespec_state *self,
 static void
 linespec_parser_new (linespec_parser *parser,
 		     int flags, const struct language_defn *language,
+		     struct program_space *search_pspace,
 		     struct symtab *default_symtab,
 		     int default_line,
 		     struct linespec_result *canonical)
@@ -2398,6 +2411,7 @@ linespec_parser_new (linespec_parser *parser,
   memset (PARSER_RESULT (parser), 0, sizeof (struct linespec));
   PARSER_EXPLICIT (parser)->line_offset.sign = LINE_OFFSET_UNKNOWN;
   linespec_state_constructor (PARSER_STATE (parser), flags, language,
+			      search_pspace,
 			      default_symtab, default_line, canonical);
 }
 
@@ -2451,7 +2465,7 @@ linespec_lex_to_end (char **stringp)
   if (stringp == NULL || *stringp == NULL)
     return;
 
-  linespec_parser_new (&parser, 0, current_language, NULL, 0, NULL);
+  linespec_parser_new (&parser, 0, current_language, NULL, NULL, 0, NULL);
   cleanup = make_cleanup (linespec_parser_delete, &parser);
   parser.lexer.saved_arg = *stringp;
   PARSER_STREAM (&parser) = orig = *stringp;
@@ -2530,6 +2544,7 @@ event_location_to_sals (linespec_parser *parser,
 
 void
 decode_line_full (const struct event_location *location, int flags,
+		  struct program_space *search_pspace,
 		  struct symtab *default_symtab,
 		  int default_line, struct linespec_result *canonical,
 		  const char *select_mode,
@@ -2550,7 +2565,8 @@ decode_line_full (const struct event_location *location, int flags,
 	      || select_mode == multiple_symbols_cancel);
   gdb_assert ((flags & DECODE_LINE_LIST_MODE) == 0);
 
-  linespec_parser_new (&parser, flags, current_language, default_symtab,
+  linespec_parser_new (&parser, flags, current_language,
+		       search_pspace, default_symtab,
 		       default_line, canonical);
   cleanups = make_cleanup (linespec_parser_delete, &parser);
   save_current_program_space ();
@@ -2603,6 +2619,7 @@ decode_line_full (const struct event_location *location, int flags,
 
 struct symtabs_and_lines
 decode_line_1 (const struct event_location *location, int flags,
+	       struct program_space *search_pspace,
 	       struct symtab *default_symtab,
 	       int default_line)
 {
@@ -2610,7 +2627,8 @@ decode_line_1 (const struct event_location *location, int flags,
   linespec_parser parser;
   struct cleanup *cleanups;
 
-  linespec_parser_new (&parser, flags, current_language, default_symtab,
+  linespec_parser_new (&parser, flags, current_language,
+		       search_pspace, default_symtab,
 		       default_line, NULL);
   cleanups = make_cleanup (linespec_parser_delete, &parser);
   save_current_program_space ();
@@ -2640,7 +2658,7 @@ decode_line_with_current_source (char *string, int flags)
 
   location = string_to_event_location (&string, current_language);
   cleanup = make_cleanup_delete_event_location (location);
-  sals = decode_line_1 (location, flags,
+  sals = decode_line_1 (location, flags, NULL,
 			cursal.symtab, cursal.line);
 
   if (*string)
@@ -2665,11 +2683,11 @@ decode_line_with_last_displayed (char *string, int flags)
   location = string_to_event_location (&string, current_language);
   cleanup = make_cleanup_delete_event_location (location);
   if (last_displayed_sal_is_valid ())
-    sals = decode_line_1 (location, flags,
+    sals = decode_line_1 (location, flags, NULL,
 			  get_last_displayed_symtab (),
 			  get_last_displayed_line ());
   else
-    sals = decode_line_1 (location, flags, (struct symtab *) NULL, 0);
+    sals = decode_line_1 (location, flags, NULL, (struct symtab *) NULL, 0);
 
   if (*string)
     error (_("Junk at end of line specification: %s"), string);
@@ -3117,10 +3135,13 @@ add_symtabs_to_list (struct symtab *symtab, void *d)
   return 0;
 }
 
-/* Given a file name, return a VEC of all matching symtabs.  */
+/* Given a file name, return a VEC of all matching symtabs.  If
+   SEARCH_PSPACE is not NULL, the search is restricted to just that
+   program space.  */
 
 static VEC (symtab_ptr) *
-collect_symtabs_from_filename (const char *file)
+collect_symtabs_from_filename (const char *file,
+			       struct program_space *search_pspace)
 {
   struct symtab_collector collector;
   struct cleanup *cleanups;
@@ -3132,27 +3153,37 @@ collect_symtabs_from_filename (const char *file)
   cleanups = make_cleanup_htab_delete (collector.symtab_table);
 
   /* Find that file's data.  */
-  ALL_PSPACES (pspace)
-  {
-    if (pspace->executing_startup)
-      continue;
+  if (search_pspace == NULL)
+    {
+      ALL_PSPACES (pspace)
+        {
+	  if (pspace->executing_startup)
+	    continue;
 
-    set_current_program_space (pspace);
-    iterate_over_symtabs (file, add_symtabs_to_list, &collector);
-  }
+	  set_current_program_space (pspace);
+	  iterate_over_symtabs (file, add_symtabs_to_list, &collector);
+	}
+    }
+  else
+    {
+      set_current_program_space (search_pspace);
+      iterate_over_symtabs (file, add_symtabs_to_list, &collector);
+    }
 
   do_cleanups (cleanups);
   return collector.symtabs;
 }
 
-/* Return all the symtabs associated to the FILENAME.  */
+/* Return all the symtabs associated to the FILENAME.  If SEARCH_PSPACE is
+   not NULL, the search is restricted to just that program space.  */
 
 static VEC (symtab_ptr) *
-symtabs_from_filename (const char *filename)
+symtabs_from_filename (const char *filename,
+		       struct program_space *search_pspace)
 {
   VEC (symtab_ptr) *result;
   
-  result = collect_symtabs_from_filename (filename);
+  result = collect_symtabs_from_filename (filename, search_pspace);
 
   if (VEC_empty (symtab_ptr, result))
     {
@@ -3189,9 +3220,10 @@ find_function_symbols (struct linespec_state *state,
   /* Try NAME as an Objective-C selector.  */
   find_imps (name, &symbol_names);
   if (!VEC_empty (const_char_ptr, symbol_names))
-    add_all_symbol_names_from_pspace (&info, NULL, symbol_names);
+    add_all_symbol_names_from_pspace (&info, state->search_pspace,
+				      symbol_names);
   else
-    add_matching_symbols_to_info (name, &info, NULL);
+    add_matching_symbols_to_info (name, &info, state->search_pspace);
 
   do_cleanups (cleanup);