Re: [RFA, doc RFA] New option set use-deprecated-index-sections

[dje@google.com]

Eli Zaretskii writes:
 > > Date: Thu, 19 Jul 2012 11:25:41 -0700
 > > cc: gdb-patches@sourceware.org
 > > From: dje@google.com
 > > 
 > > How about this?
 > 
 > Fine with me, thanks.

Thanks.
And I committed this to the 7.5 branch.

2012-07-20  Doug Evans  <dje@google.com>

	* NEWS: Document new options "set/show use-deprecated-index-sections",
	and delete reference to --use-deprecated-index-sections.
	* symfile.h (use_deprecated_index_sections): Delete.
	* dwarf2read.c (use_deprecated_index_sections): Make static.
	(read_index_from_section): Update wording of how to load
	deprecated index sections.
	(_initialize_dwarf2_read): New options
	"set/show use-deprecated-index-sections".
	* main.c (captured_main): Delete --use-deprecated-index-sections.

	doc/
	* gdb.texinfo (Mode Options): Delete --use-deprecated-index-sections.
	(Index Files): Document how to control the use of deprecated index
	sections.
	(Index Section Format): Replace --use-deprecated-index-sections with
	"set use-deprecated-index-sections on".

Index: NEWS
===================================================================
RCS file: /cvs/src/src/gdb/NEWS,v
retrieving revision 1.533.2.1
diff -u -p -r1.533.2.1 NEWS
--- NEWS	18 Jul 2012 15:56:55 -0000	1.533.2.1
+++ NEWS	20 Jul 2012 17:57:19 -0000
@@ -112,11 +112,11 @@
 * The .gdb_index section has been updated to include symbols for
   inlined functions.  GDB will ignore older .gdb_index sections by
   default, which could cause symbol files to be loaded more slowly
-  until their .gdb_index sections can be recreated.  The new option
-  --use-deprecated-index-sections will cause GDB to use any older
-  .gdb_index sections it finds.  This will restore performance, but
-  the ability to set breakpoints on inlined functions will be lost
-  in symbol files with older .gdb_index sections.
+  until their .gdb_index sections can be recreated.  The new command
+  "set use-deprecated-index-sections on" will cause GDB to use any older
+  .gdb_index sections it finds.  This will restore performance, but the
+  ability to set breakpoints on inlined functions will be lost in symbol
+  files with older .gdb_index sections.
 
   The .gdb_index section has also been updated to record more information
   about each symbol.  This speeds up the "info variables", "info functions"
@@ -137,6 +137,10 @@
 
 * New commands
 
+  ** "set use-deprecated-index-sections on|off"
+     "show use-deprecated-index-sections on|off"
+     Controls the use of deprecated .gdb_index sections.
+
   ** "catch load" and "catch unload" can be used to stop when a shared
      library is loaded or unloaded, respectively.
 
Index: dwarf2read.c
===================================================================
RCS file: /cvs/src/src/gdb/dwarf2read.c,v
retrieving revision 1.687
diff -u -p -r1.687 dwarf2read.c
--- dwarf2read.c	16 Jul 2012 03:22:40 -0000	1.687
+++ dwarf2read.c	20 Jul 2012 17:57:19 -0000
@@ -93,7 +93,7 @@ static int dwarf2_die_debug = 0;
 static int check_physname = 0;
 
 /* When non-zero, do not reject deprecated .gdb_index sections.  */
-int use_deprecated_index_sections = 0;
+static int use_deprecated_index_sections = 0;
 
 static int pagesize;
 
@@ -2558,15 +2558,17 @@ dwarf2_read_index (struct objfile *objfi
      Versions earlier than 6 did not emit psymbols for inlined
      functions.  Using these files will cause GDB not to be able to
      set breakpoints on inlined functions by name, so we ignore these
-     indices unless the --use-deprecated-index-sections command line
-     option was supplied.  */
+     indices unless the user has done
+     "set use-deprecated-index-sections on".  */
   if (version < 6 && !use_deprecated_index_sections)
     {
       static int warning_printed = 0;
       if (!warning_printed)
 	{
-	  warning (_("Skipping deprecated .gdb_index section in %s, pass "
-		     "--use-deprecated-index-sections to use them anyway"),
+	  warning (_("\
+Skipping deprecated .gdb_index section in %s.\n\
+Do \"set use-deprecated-index-sections on\" before the file is read\n\
+to use the section anyway."),
 		   objfile->name);
 	  warning_printed = 1;
 	}
@@ -19387,6 +19389,18 @@ the demangler."),
 			   NULL, show_check_physname,
 			   &setdebuglist, &showdebuglist);
 
+  add_setshow_boolean_cmd ("use-deprecated-index-sections",
+			   no_class, &use_deprecated_index_sections, _("\
+Set whether to use deprecated gdb_index sections."), _("\
+Show whether to use deprecated gdb_index sections."), _("\
+When enabled, deprecated .gdb_index sections are used anyway.\n\
+Normally they are ignored either because of a missing feature or\n\
+performance issue.\n\
+Warning: This option must be enabled before gdb reads the file."),
+			   NULL,
+			   NULL,
+			   &setlist, &showlist);
+
   c = add_cmd ("gdb-index", class_files, save_gdb_index_command,
 	       _("\
 Save a gdb-index file.\n\
Index: main.c
===================================================================
RCS file: /cvs/src/src/gdb/main.c,v
retrieving revision 1.110
diff -u -p -r1.110 main.c
--- main.c	2 Jul 2012 12:05:00 -0000	1.110
+++ main.c	20 Jul 2012 17:57:19 -0000
@@ -471,8 +471,6 @@ captured_main (void *data)
       {"args", no_argument, &set_args, 1},
       {"l", required_argument, 0, 'l'},
       {"return-child-result", no_argument, &return_child_result, 1},
-      {"use-deprecated-index-sections", no_argument,
-       &use_deprecated_index_sections, 1},
       {0, no_argument, 0, 0}
     };
 
Index: symfile.h
===================================================================
RCS file: /cvs/src/src/gdb/symfile.h,v
retrieving revision 1.109
diff -u -p -r1.109 symfile.h
--- symfile.h	24 May 2012 22:14:35 -0000	1.109
+++ symfile.h	20 Jul 2012 17:57:19 -0000
@@ -676,9 +676,6 @@ extern void dwarf2_build_frame_info (str
 
 void dwarf2_free_objfile (struct objfile *);
 
-/* Whether to use deprecated .gdb_index sections.  */
-extern int use_deprecated_index_sections;
-
 /* From mdebugread.c */
 
 /* Hack to force structures to exist before use in parameter list.  */
Index: doc/gdb.texinfo
===================================================================
RCS file: /cvs/src/src/gdb/doc/gdb.texinfo,v
retrieving revision 1.990
diff -u -p -r1.990 gdb.texinfo
--- doc/gdb.texinfo	5 Jul 2012 01:08:24 -0000	1.990
+++ doc/gdb.texinfo	20 Jul 2012 17:57:20 -0000
@@ -1247,13 +1247,6 @@ memory usage after it completes each com
 This option causes @value{GDBN} to print its version number and
 no-warranty blurb, and exit.
 
-@item -use-deprecated-index-sections
-@cindex @code{--use-deprecated-index-sections}
-This option causes @value{GDBN} to read and use deprecated
-@samp{.gdb_index} sections from symbol files.  This can speed up
-startup, but may result in some functionality being lost.
-@xref{Index Section Format}.
-
 @end table
 
 @node Startup
@@ -16753,6 +16746,28 @@ $ objcopy --add-section .gdb_index=symfi
     --set-section-flags .gdb_index=readonly symfile symfile
 @end smallexample
 
+@value{GDBN} will normally ignore older versions of @file{.gdb_index}
+sections that have been deprecated.  Usually they are deprecated because
+they are missing a new feature or have performance issues.
+To tell @value{GDBN} to use a deprecated index section anyway
+specify @code{set use-deprecated-index-sections on}.
+The default is @code{off}.
+This can speed up startup, but may result in some functionality being lost.
+@xref{Index Section Format}.
+
+@emph{Warning:} Setting @code{use-deprecated-index-sections} to @code{on}
+must be done before gdb reads the file.  The following will not work:
+
+@smallexample
+$ gdb -ex "set use-deprecated-index-sections on" <program>
+@end smallexample
+
+Instead you must do, for example,
+
+@smallexample
+$ gdb -iex "set use-deprecated-index-sections on" <program>
+@end smallexample
+
 There are currently some limitation on indices.  They only work when
 for DWARF debugging information, not stabs.  And, they do not
 currently work for programs using Ada.
@@ -40408,7 +40423,7 @@ Version 4 uses a different hashing funct
 Version 6 includes symbols for inlined functions, whereas versions 4
 and 5 do not.  Version 7 adds attributes to the CU indices in the
 symbol table.  @value{GDBN} will only read version 4, 5, or 6 indices
-if the @code{--use-deprecated-index-sections} option is used.
+by specifying @code{set use-deprecated-index-sections on}.
 
 @item
 The offset, from the start of the file, of the CU list.