[patch] Avoid computing fullname if unused.

[dje@google.com (Doug Evans)]

Hi.
"b functi<tab>" takes longer than it should.
gdb spends a lot of time computing a file's "fullname" and then
never using the result.  See maybe_add_partial_symtab_filename.

I will check this in in a few days if there are no objections.

2011-11-06  Doug Evans  <dje@google.com>

	* dwarf2read.c (dw2_map_symbol_filenames): New parameter
	`need_fullname'.
	* psymtab.c (map_symbol_filenames_psymtab): Ditto.
	(map_partial_symbol_filenames): Ditto.  All callers updated.
	* psymtab.h (map_partial_symbol_filenames): Update prototype.
	* symfile.h (struct quick_symbol_functions, map_symbol_filenames): New
	parameter need_fullname.

Index: dwarf2read.c
===================================================================
RCS file: /cvs/src/src/gdb/dwarf2read.c,v
retrieving revision 1.578
diff -u -p -r1.578 dwarf2read.c
--- dwarf2read.c	20 Oct 2011 23:13:01 -0000	1.578
+++ dwarf2read.c	7 Nov 2011 06:07:10 -0000
@@ -2810,7 +2817,7 @@ dw2_find_pc_sect_symtab (struct objfile 
 
 static void
 dw2_map_symbol_filenames (struct objfile *objfile, symbol_filename_ftype *fun,
-			  void *data)
+			  void *data, int need_fullname)
 {
   int i;
 
@@ -2832,8 +2839,12 @@ dw2_map_symbol_filenames (struct objfile
 
       for (j = 0; j < file_data->num_file_names; ++j)
 	{
-	  const char *this_real_name = dw2_get_real_path (objfile, file_data,
-							  j);
+	  const char *this_real_name;
+
+	  if (need_fullname)
+	    this_real_name = dw2_get_real_path (objfile, file_data, j);
+	  else
+	    this_real_name = NULL;
 	  (*fun) (file_data->file_names[j], this_real_name, data);
 	}
     }
Index: psymtab.c
===================================================================
RCS file: /cvs/src/src/gdb/psymtab.c,v
retrieving revision 1.31
diff -u -p -r1.31 psymtab.c
--- psymtab.c	28 Oct 2011 17:29:37 -0000	1.31
+++ psymtab.c	7 Nov 2011 06:07:10 -0000
@@ -1082,7 +1089,8 @@ read_psymtabs_with_filename (struct objf
 
 static void
 map_symbol_filenames_psymtab (struct objfile *objfile,
-			      symbol_filename_ftype *fun, void *data)
+			      symbol_filename_ftype *fun, void *data,
+			      int need_fullname)
 {
   struct partial_symtab *ps;
 
@@ -1094,7 +1102,10 @@ map_symbol_filenames_psymtab (struct obj
 	continue;
 
       QUIT;
-      fullname = psymtab_to_fullname (ps);
+      if (need_fullname)
+	fullname = psymtab_to_fullname (ps);
+      else
+	fullname = NULL;
       (*fun) (ps->filename, fullname, data);
     }
 }
@@ -1916,13 +1927,15 @@ expand_partial_symbol_names (int (*fun) 
 }
 
 void
-map_partial_symbol_filenames (symbol_filename_ftype *fun, void *data)
+map_partial_symbol_filenames (symbol_filename_ftype *fun, void *data,
+			      int need_fullname)
 {
   struct objfile *objfile;
 
   ALL_OBJFILES (objfile)
   {
     if (objfile->sf)
-      objfile->sf->qf->map_symbol_filenames (objfile, fun, data);
+      objfile->sf->qf->map_symbol_filenames (objfile, fun, data,
+					     need_fullname);
   }
 }
Index: psymtab.h
===================================================================
RCS file: /cvs/src/src/gdb/psymtab.h,v
retrieving revision 1.8
diff -u -p -r1.8 psymtab.h
--- psymtab.h	10 Jun 2011 21:48:04 -0000	1.8
+++ psymtab.h	7 Nov 2011 06:07:10 -0000
@@ -33,7 +33,8 @@ extern struct bcache *psymbol_bcache_get
 void expand_partial_symbol_names (int (*fun) (const char *, void *),
 				  void *data);
 
-void map_partial_symbol_filenames (symbol_filename_ftype *fun, void *data);
+void map_partial_symbol_filenames (symbol_filename_ftype *fun, void *data,
+				   int need_fullname);
 
 extern const struct quick_symbol_functions psym_functions;
 
Index: symfile.h
===================================================================
RCS file: /cvs/src/src/gdb/symfile.h,v
retrieving revision 1.96
diff -u -p -r1.96 symfile.h
--- symfile.h	9 Oct 2011 18:37:27 -0000	1.96
+++ symfile.h	7 Nov 2011 06:07:10 -0000
@@ -289,9 +289,11 @@ struct quick_symbol_functions
 
   /* Call a callback for every file defined in OBJFILE whose symtab is
      not already read in.  FUN is the callback.  It is passed the file's
-     FILENAME, the file's FULLNAME, and the DATA passed to this function.  */
+     FILENAME, the file's FULLNAME (if need_fullname is non-zero), and
+     the DATA passed to this function.  */
   void (*map_symbol_filenames) (struct objfile *objfile,
-				symbol_filename_ftype *fun, void *data);
+				symbol_filename_ftype *fun, void *data,
+				int need_fullname);
 };
 
 /* Structure to keep track of symbol reading functions for various
Index: symtab.c
===================================================================
RCS file: /cvs/src/src/gdb/symtab.c,v
retrieving revision 1.285
diff -u -p -r1.285 symtab.c
--- symtab.c	29 Oct 2011 07:26:07 -0000	1.285
+++ symtab.c	7 Nov 2011 06:07:10 -0000
@@ -2881,7 +2890,8 @@ sources_info (char *ignore, int from_tty
 		   "will be read in on demand:\n\n");
 
   first = 1;
-  map_partial_symbol_filenames (output_partial_symbol_filename, &first);
+  map_partial_symbol_filenames (output_partial_symbol_filename, &first,
+				TRUE /*need_fullname*/);
   printf_filtered ("\n");
 }
 
@@ -4314,7 +4324,8 @@ make_source_files_completion_list (char 
   datum.list = &list;
   datum.list_used = &list_used;
   datum.list_alloced = &list_alloced;
-  map_partial_symbol_filenames (maybe_add_partial_symtab_filename, &datum);
+  map_partial_symbol_filenames (maybe_add_partial_symtab_filename, &datum,
+				FALSE /*need_fullname*/);
   discard_cleanups (back_to);
 
   return list;
Index: mi/mi-cmd-file.c
===================================================================
RCS file: /cvs/src/src/gdb/mi/mi-cmd-file.c,v
retrieving revision 1.16
diff -u -p -r1.16 mi-cmd-file.c
--- mi/mi-cmd-file.c	4 Aug 2011 19:10:14 -0000	1.16
+++ mi/mi-cmd-file.c	7 Nov 2011 06:07:12 -0000
@@ -109,7 +109,8 @@ mi_cmd_file_list_exec_source_files (char
     ui_out_end (uiout, ui_out_type_tuple);
   }
 
-  map_partial_symbol_filenames (print_partial_file_name, NULL);
+  map_partial_symbol_filenames (print_partial_file_name, NULL,
+				TRUE /*need_fullname*/);
 
   ui_out_end (uiout, ui_out_type_list);
 }