gdb/mi: Add -max-results parameter to some -symbol-info-* commands

Adds a new parameter -max-results to -symbol-info-functions,
-symbol-info-variables, -symbol-info-types, and -symbol-info-modules.
This parameter limits the number of results returned.

This change still leaves -symbol-info-module-functions and
-symbol-info-module-variables always returning all results, fixing
these commands is slightly harder.

There's currently no mechanism for the user of these commands to know
if the result list has been truncated if you get back the maximum
number of results, so if there are exactly 10 functions and you call
'-symbol-info-functions --max-results 10' the reply would appear no
different than if you had 20 functions and called with a max of 10.
Right now, if you get back the maximum then you should assume that
there might be more results available.

One other thing to note is that the global_symbol_searcher::search by
default returns SIZE_MAX results, there's no longer a mechanism to
return an unlimited number of results, though hopefully this will not
be a huge issue.

gdb/ChangeLog:

	* mi/mi-symbol-cmds.c (mi_symbol_info): Take extra parameter, and
	add it into the search spec.
	(parse_max_results_option): New function.
	(mi_info_functions_or_variables): Parse -max-results flag and pass
	it to mi_symbol_info.
	(mi_cmd_symbol_info_modules): Likewise.
	(mi_cmd_symbol_info_types): Likewise.
	* symtab.c (global_symbol_searcher::add_matching_symbols): Change
	return type to bool, change result container into a set, and don't
	add new results if we have enough already.
	(global_symbol_searcher::add_matching_msymbols): Change return
	type to bool, and don't add new results if we have enough already.
	(sort_search_symbols_remove_dups): Delete.
	(global_symbol_searcher::search): Early exit from search loop when
	we have enough results.  Use a std::set to collect the results
	from calling add_matching_symbols.
	* symtab.h (global_symbol_searcher) <set_max_seach_results>: New
	member function.
	(global_symbol_searcher) <m_max_search_results>: New member
	variable.
	(global_symbol_searcher) <add_matching_symbols>: Update header
	comment and change return type to bool.
	(global_symbol_searcher) <add_matching_msymbols>: Update header
	comment and change return type to bool.

gdb/doc/ChangeLog:

	* doc/gdb.texinfo (GDB/MI Symbol Query): Add documentation of
	-max-results to some -symbol-info-* commands.

gdb/testsuite/ChangeLog:

	* gdb.mi/mi-sym-info.exp: Add tests for -max-results parameter.

Change-Id: I90a28feb55b388fb46461a096c5db08b6b0bd427

1 files changed, 26 insertions, 7 deletions

diff --git a/gdb/symtab.h b/gdb/symtab.h
index 41abf1f..e8321d4 100644
--- a/gdb/symtab.h
+++ b/gdb/symtab.h
@@ -23,6 +23,7 @@
 #include <array>
 #include <vector>
 #include <string>
+#include <set>
 #include "gdbsupport/gdb_vecs.h"
 #include "gdbtypes.h"
 #include "gdb_obstack.h"
@@ -2092,6 +2093,12 @@ public:
     m_exclude_minsyms = exclude_minsyms;
   }
 
+  /* Set the maximum number of search results to be returned.  */
+  void set_max_search_results (size_t max_search_results)
+  {
+    m_max_search_results = max_search_results;
+  }
+
   /* Search the symbols from all objfiles in the current program space
      looking for matches as defined by the current state of this object.
 
@@ -2125,6 +2132,10 @@ private:
      be included in the results, otherwise they are excluded.  */
   bool m_exclude_minsyms = false;
 
+  /* Maximum number of search results.  We currently impose a hard limit
+     of SIZE_MAX, there is no "unlimited".  */
+  size_t m_max_search_results = SIZE_MAX;
+
   /* Expand symtabs in OBJFILE that match PREG, are of type M_KIND.  Return
      true if any msymbols were seen that we should later consider adding to
      the results list.  */
@@ -2132,15 +2143,23 @@ private:
 		       const gdb::optional<compiled_regex> &preg) const;
 
   /* Add symbols from symtabs in OBJFILE that match PREG, and TREG, and are
-     of type M_KIND, to the results vector RESULTS.  */
-  void add_matching_symbols (objfile *objfile,
+     of type M_KIND, to the results set RESULTS_SET.  Return false if we
+     stop adding results early due to having already found too many results
+     (based on M_MAX_SEARCH_RESULTS limit), otherwise return true.
+     Returning true does not indicate that any results were added, just
+     that we didn't _not_ add a result due to reaching MAX_SEARCH_RESULTS.  */
+  bool add_matching_symbols (objfile *objfile,
 			     const gdb::optional<compiled_regex> &preg,
 			     const gdb::optional<compiled_regex> &treg,
-			     std::vector<symbol_search> *results) const;
-
-  /* Add msymbols from OBJFILE that match PREG and M_KIND, to the
-     results vector RESULTS.  */
-  void add_matching_msymbols (objfile *objfile,
+			     std::set<symbol_search> *result_set) const;
+
+  /* Add msymbols from OBJFILE that match PREG and M_KIND, to the results
+     vector RESULTS.  Return false if we stop adding results early due to
+     having already found too many results (based on max search results
+     limit M_MAX_SEARCH_RESULTS), otherwise return true.  Returning true
+     does not indicate that any results were added, just that we didn't
+     _not_ add a result due to reaching MAX_SEARCH_RESULTS.  */
+  bool add_matching_msymbols (objfile *objfile,
 			      const gdb::optional<compiled_regex> &preg,
 			      std::vector<symbol_search> *results) const;