[PATCH, doc RFA] New option: set print symbol-loading

[Doug Evans <dje at google dot com>]

Hi.

I added this patch a few years ago, but
I got uncomfortable with keeping it upstream.
https://sourceware.org/ml/gdb-patches/2008-07/msg00165.html

It's proven quite useful here over the years (and continues to be useful),
so I'm resubmitting it (it's changed a bit since then, but the main idea
is still the same).

The motivation for the patch is that it's not helpful to have 100s (or 1000s)
of "Reading symbols from" messages printed on the screen.

Note: This patch is written as if the following patch hasn't been applied:
https://sourceware.org/ml/gdb-patches/2014-02/msg00742.html
I'll update the patch before committing based on whether it does get applied.

Regression tested on amd64-linux.

2014-02-24  Doug Evans  <dje@google.com>

	New option "set print symbol-loading".
	* NEWS: Mention it.
	* solib.c (solib_read_symbols): Only print symbol loading messages
	if requested.
	(solib_add): If symbol loading is in "brief" mode, notify user
	symbols are being loaded.
	(reload_shared_libraries_1): Ditto.
	* symfile.c (print_symbol_loading_off): New static global.
	(print_symbol_loading_brief): New static global.
	(print_symbol_loading_full): New static global.
	(print_symbol_loading_enums): New static global.
	(print_symbol_loading): New static global.
	(print_symbol_loading_p): New function.
	(symbol_file_add_with_addrs): Only print symbol loading messages
	if requested.
	(_initialize_symfile): Register "print symbol-loading" set/show
	command.
	* symfile.h (print_symbol_loading_p): Declare.

	doc/
	* gdb.texinfo (Symbols): Document set/show print symbol-loading.

	testsuite/
	* gdb.base/print-symbol-loading-lib.c: New file.
	* gdb.base/print-symbol-loading-main.c: New file.
	* gdb.base/print-symbol-loading.exp: New file.

diff --git a/gdb/NEWS b/gdb/NEWS
index 2a384ba..df233fc 100644
--- a/gdb/NEWS
+++ b/gdb/NEWS
@@ -28,6 +28,13 @@ info auto-load guile-scripts [regexp]
 
 * New options
 
+set print symbol-loading (off|brief|full)
+show print symbol-loading
+  Control whether to print informational messages when loading symbol
+  information for a file.  The default is "full", but when debugging
+  programs with large numbers of shared libraries the amount of output
+  becomes less useful.
+
 set guile print-stack (none|message|full)
 show guile print-stack
   Show a stack trace when an error is encountered in a Guile script.
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index de5ac63..9037bd2 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -16184,6 +16184,28 @@ is printed as follows:
 @item show opaque-type-resolution
 Show whether opaque types are resolved or not.
 
+@kindex set print symbol-loading
+@cindex print messages when symbols are loaded
+@item set print symbol-loading
+@itemx set print symbol-loading full
+@itemx set print symbol-loading brief
+@itemx set print symbol-loading off
+The @code{set print symbol-loading} command allows you to control the
+printing of messages when @value{GDBN} loads symbol information.
+By default a message is printed for the executable and one for each
+shared library, and normally this is what you want.  However, when
+debugging apps with large numbers of shared libraries these messages
+can be annoying.
+When set to @code{brief} a message is printed for each executable,
+and when @value{GDBN} loads a collection of shared libraries at once
+it will only print one message regardless of the number of shared
+libraries.  When set to @code{off} no messages are printed.
+
+@kindex show print symbol-loading
+@item show print symbol-loading
+Show whether messages will be printed when a @value{GDBN} command
+entered from the keyboard causes symbol information to be loaded.
+
 @kindex maint print symbols
 @cindex symbol dump
 @kindex maint print psymbols
diff --git a/gdb/solib.c b/gdb/solib.c
index 3350bfd..84942d3 100644
--- a/gdb/solib.c
+++ b/gdb/solib.c
@@ -650,7 +650,7 @@ solib_read_symbols (struct so_list *so, int flags)
 			   so->so_name);
       else
 	{
-	  if (from_tty || info_verbose)
+	  if (print_symbol_loading_p (from_tty, 0, 1))
 	    printf_unfiltered (_("Loaded symbols for %s\n"), so->so_name);
 	  so->symbols_loaded = 1;
 	}
@@ -905,6 +905,15 @@ solib_add (char *pattern, int from_tty,
 {
   struct so_list *gdb;
 
+  if (print_symbol_loading_p (from_tty, 0, 0))
+    {
+      if (pattern != NULL)
+	printf_unfiltered (_("Loading symbols for shared libraries.\n"));
+      else
+	printf_unfiltered (_("Loading symbols for shared libraries: %s\n"),
+			   pattern);
+    }
+
   current_program_space->solib_add_generation++;
 
   if (pattern)
@@ -1277,6 +1286,9 @@ reload_shared_libraries_1 (int from_tty)
   struct so_list *so;
   struct cleanup *old_chain = make_cleanup (null_cleanup, NULL);
 
+  if (print_symbol_loading_p (from_tty, 0, 0))
+    printf_unfiltered (_("Loading symbols for shared libraries.\n"));
+
   for (so = so_list_head; so != NULL; so = so->next)
     {
       char *filename, *found_pathname = NULL;
diff --git a/gdb/symfile.c b/gdb/symfile.c
index 06d2119..9edb3da 100644
--- a/gdb/symfile.c
+++ b/gdb/symfile.c
@@ -143,6 +143,20 @@ DEF_VEC_O (registered_sym_fns);
 
 static VEC (registered_sym_fns) *symtab_fns = NULL;
 
+/* Values for "set print symbol-loading".  */
+
+const char print_symbol_loading_off[] = "off";
+const char print_symbol_loading_brief[] = "brief";
+const char print_symbol_loading_full[] = "full";
+static const char *print_symbol_loading_enums[] =
+{
+  print_symbol_loading_off,
+  print_symbol_loading_brief,
+  print_symbol_loading_full,
+  NULL
+};
+static const char *print_symbol_loading = print_symbol_loading_full;
+
 /* If non-zero, shared library symbols will be added automatically
    when the inferior is created, new libraries are loaded, or when
    attaching to the inferior.  This is almost always what users will
@@ -156,6 +170,31 @@ static VEC (registered_sym_fns) *symtab_fns = NULL;
 int auto_solib_add = 1;
 
 
+/* Return non-zero if symbol-loading messages should be printed.
+   FROM_TTY is the standard from_tty argument to gdb commands.
+   If EXEC is non-zero the messages are for the executable.
+   Otherwise, messages are for shared libraries.
+   If FULL is non-zero then the caller is printing a detailed message.
+   E.g., the message includes the shared library name.
+   Otherwise, the caller is printing a brief "summary" message.  */
+
+int
+print_symbol_loading_p (int from_tty, int exec, int full)
+{
+  if (!from_tty && !info_verbose)
+    return 0;
+
+  if (exec)
+    {
+      /* We don't check FULL for executables, there are few such
+	 messages, therefore brief == full.  */
+      return print_symbol_loading != print_symbol_loading_off;
+    }
+  if (full)
+    return print_symbol_loading == print_symbol_loading_full;
+  return print_symbol_loading == print_symbol_loading_brief;
+}
+
 /* True if we are reading a symbol table.  */
 
 int currently_reading_symtab = 0;
@@ -1111,7 +1150,7 @@ symbol_file_add_with_addrs (bfd *abfd, const char *name, int add_flags,
   struct objfile *objfile;
   const int from_tty = add_flags & SYMFILE_VERBOSE;
   const int mainline = add_flags & SYMFILE_MAINLINE;
-  const int should_print = ((from_tty || info_verbose)
+  const int should_print = (print_symbol_loading_p (from_tty, mainline, 1)
 			    && (readnow_symbol_files
 				|| (add_flags & SYMFILE_NO_READ) == 0));
 
@@ -3990,4 +4029,18 @@ each global debug-file-directory component prepended."),
 				     NULL,
 				     show_debug_file_directory,
 				     &setlist, &showlist);
+
+  add_setshow_enum_cmd ("symbol-loading", no_class,
+			print_symbol_loading_enums, &print_symbol_loading,
+			_("\
+Set printing of symbol loading messages."), _("\
+Show printing of symbol loading messages."), _("\
+off   == turn all messages off\n\
+brief == print messages for the executable,\n\
+         and brief messages for shared libraries\n\
+full  == print messages for the executable,\n\
+         and messages for each shared library."),
+			NULL,
+			NULL,
+			&setprintlist, &showprintlist);
 }
diff --git a/gdb/symfile.h b/gdb/symfile.h
index 17599be..24110f9 100644
--- a/gdb/symfile.h
+++ b/gdb/symfile.h
@@ -508,6 +508,8 @@ extern bfd *gdb_bfd_open_maybe_remote (const char *);
 
 extern int get_section_index (struct objfile *, char *);
 
+extern int print_symbol_loading_p (int from_tty, int mainline, int full);
+
 /* Utility functions for overlay sections: */
 extern enum overlay_debugging_state
 {
diff --git a/gdb/testsuite/gdb.base/print-symbol-loading-lib.c b/gdb/testsuite/gdb.base/print-symbol-loading-lib.c
new file mode 100644
index 0000000..1e31e53
--- /dev/null
+++ b/gdb/testsuite/gdb.base/print-symbol-loading-lib.c
@@ -0,0 +1,21 @@
+/* Copyright 2010-2014 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+void
+lib (void)
+{
+}
diff --git a/gdb/testsuite/gdb.base/print-symbol-loading-main.c b/gdb/testsuite/gdb.base/print-symbol-loading-main.c
new file mode 100644
index 0000000..8379b58
--- /dev/null
+++ b/gdb/testsuite/gdb.base/print-symbol-loading-main.c
@@ -0,0 +1,25 @@
+/* Copyright 2010-2014 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+extern void lib (void);
+
+int
+main (void)
+{
+  lib ();
+  return 0;
+}
diff --git a/gdb/testsuite/gdb.base/print-symbol-loading.exp b/gdb/testsuite/gdb.base/print-symbol-loading.exp
new file mode 100644
index 0000000..a6f93fc
--- /dev/null
+++ b/gdb/testsuite/gdb.base/print-symbol-loading.exp
@@ -0,0 +1,144 @@
+# Copyright 2012-2014 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# Test the "print symbol-loading" option.
+
+if {[skip_shlib_tests]} {
+    return 0
+}
+
+standard_testfile print-symbol-loading-main.c
+set libfile print-symbol-loading-lib
+set srcfile_lib ${libfile}.c
+set binfile_lib [standard_output_file ${libfile}.so]
+set gcorefile ${binfile}.gcore
+set objfile [standard_output_file ${testfile}.o]
+
+if { [gdb_compile_shlib ${srcdir}/${subdir}/${srcfile_lib} ${binfile_lib} {debug}] != ""
+     || [gdb_compile ${srcdir}/${subdir}/${srcfile} ${objfile} object {debug}] != "" } {
+    untested ${testfile}.exp
+    return -1
+}
+set opts [list debug shlib=${binfile_lib}]
+if { [gdb_compile ${objfile} ${binfile} executable $opts] != "" } {
+    untested ${testfile}.exp
+    return -1
+}
+
+clean_restart ${binfile}
+gdb_load_shlibs ${binfile_lib}
+
+# Does this gdb support gcore?
+set test "help gcore"
+gdb_test_multiple $test $test {
+    -re "Undefined command: .gcore.*\r\n$gdb_prompt $" {
+	# gcore command not supported -- nothing to test here.
+	unsupported "gdb does not support gcore on this target"
+	return -1
+    }
+    -re "Save a core file .*\r\n$gdb_prompt $" {
+	pass $test
+    }
+}
+
+if ![runto lib] {
+    return -1
+}
+
+if {![gdb_gcore_cmd $gcorefile "save a corefile"]} {
+    return -1
+}
+
+proc test_load_core { print_symbol_loading } {
+    global binfile binfile_lib gcorefile srcdir subdir
+    with_test_prefix "core ${print_symbol_loading}" {
+	gdb_exit
+	gdb_start
+	gdb_reinitialize_dir $srcdir/$subdir
+	gdb_test_no_output "set print symbol-loading $print_symbol_loading"
+	if { ${print_symbol_loading} != "off" } {
+	    gdb_test "file $binfile" "Reading symbols from.*done\\." "file"
+	} else {
+	    gdb_test_no_output "file $binfile" "file"
+	}
+	# Rename the shared lib so gdb can't find it.
+	remote_exec host "mv -f ${binfile_lib} ${binfile_lib}.save"
+	gdb_test "core ${gcorefile}" "Core was generated by .*" \
+	    "re-load generated corefile"
+	# Now put it back and use "set solib-search-path" to trigger
+	# loading of symbols.
+	remote_exec host "mv -f ${binfile_lib}.save ${binfile_lib}"
+	set test_name "load shared-lib"
+	switch "${print_symbol_loading}" {
+	    "off" {
+		gdb_test_no_output "set solib-search-path [file dirname ${binfile_lib}]" \
+		    ${test_name}
+	    }
+	    "brief" {
+		gdb_test "set solib-search-path [file dirname ${binfile_lib}]" \
+		    "Loading symbols for shared libraries\\." \
+		    ${test_name}
+	    }
+	    "full" {
+		gdb_test "set solib-search-path [file dirname ${binfile_lib}]" \
+		    "Reading symbols from.*Loaded symbols for.*" \
+		    ${test_name}
+	    }
+	}
+	gdb_test "frame" "#0 \[^\r\n\]* lib .*" "library got loaded"
+    }
+}
+
+test_load_core off
+test_load_core brief
+test_load_core full
+
+# Now test the sharedlibrary command.
+
+proc test_load_shlib { print_symbol_loading } {
+    global binfile
+    with_test_prefix "shlib ${print_symbol_loading}" {
+	clean_restart ${binfile}
+	gdb_test_no_output "set auto-solib-add off"
+	if ![runto_main] {
+	    return -1
+	}
+	gdb_test_no_output "set print symbol-loading $print_symbol_loading"
+	set test_name "load shared-lib"
+	switch ${print_symbol_loading} {
+	    "off" {
+		gdb_test_no_output "sharedlibrary .*" \
+		    ${test_name}
+	    }
+	    "brief" {
+		gdb_test "sharedlibrary .*" \
+		    "Loading symbols for shared libraries\\." \
+		    ${test_name}
+	    }
+	    "full" {
+		gdb_test "sharedlibrary .*" \
+		    "Reading symbols from.*Loaded symbols for.*" \
+		    ${test_name}
+	    }
+	}
+	gdb_breakpoint "lib"
+	gdb_continue_to_breakpoint "lib"
+	gdb_test "frame" "#0 \[^\r\n\]* lib .*" "library got loaded"
+    }
+}
+
+test_load_shlib off
+test_load_shlib brief
+test_load_shlib full