gdb/fortran: Add new 'info modules' command

Add a new command 'info modules' that lists all of the modules GDB
knows about from the debug information.

A module is a debugging entity in the DWARF defined with
DW_TAG_module, currently Fortran is known to use this tag for its
modules.  I'm not aware of any other language that currently makes use
of DW_TAG_module.

The output style is similar to the 'info type' output:

    (gdb) info modules
    All defined modules:

    File info-types.f90:
    16:     mod1
    24:     mod2
    (gdb)

Where the user is told the file the module is defined in and, on the
left hand side, the line number at which the module is defined along
with the name of the module.

This patch is a new implementation of an idea originally worked on by
Mark O'Connor, Chris January, David Lecomber, and Xavier Oro from ARM.

gdb/ChangeLog:

	* dwarf2read.c (dw2_symtab_iter_next): Handle MODULE_DOMAIN.
	(dw2_expand_marked_cus): Handle MODULES_DOMAIN.
	(dw2_debug_names_iterator::next): Handle MODULE_DOMAIN and
	MODULES_DOMAIN.
	(scan_partial_symbols): Only create partial module symbols for non
	declarations.
	* psymtab.c (recursively_search_psymtabs): Handle MODULE_DOMAIN
	and MODULES_DOMAIN.
	* symtab.c (search_domain_name): Likewise.
	(search_symbols): Likewise.
	(print_symbol_info): Likewise.
	(symtab_symbol_info): Likewise.
	(info_modules_command): New function.
	(_initialize_symtab): Register 'info modules' command.
	* symtab.h (enum search_domain): Add MODULES_DOMAIN.
	* NEWS: Mention new 'info modules' command.

gdb/doc/ChangeLog:

	* gdb.texinfo (Symbols): Document new 'info modules' command.

gdb/testsuite/ChangeLog:

	* gdb.fortran/info-modules.exp: New file.
	* gdb.fortran/info-types.exp: Build with new file.
	* gdb.fortran/info-types.f90: Include and use new module.
	* gdb.fortran/info-types-2.f90: New file.

Change-Id: I2b781dd5a06bcad04620ccdc45f01a0f711adfad

13 files changed, 201 insertions, 9 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 9c97b82..6dca965 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,22 @@
+2019-10-31  Andrew Burgess  <andrew.burgess@embecosm.com>
+
+	* dwarf2read.c (dw2_symtab_iter_next): Handle MODULE_DOMAIN.
+	(dw2_expand_marked_cus): Handle MODULES_DOMAIN.
+	(dw2_debug_names_iterator::next): Handle MODULE_DOMAIN and
+	MODULES_DOMAIN.
+	(scan_partial_symbols): Only create partial module symbols for non
+	declarations.
+	* psymtab.c (recursively_search_psymtabs): Handle MODULE_DOMAIN
+	and MODULES_DOMAIN.
+	* symtab.c (search_domain_name): Likewise.
+	(search_symbols): Likewise.
+	(print_symbol_info): Likewise.
+	(symtab_symbol_info): Likewise.
+	(info_modules_command): New function.
+	(_initialize_symtab): Register 'info modules' command.
+	* symtab.h (enum search_domain): Add MODULES_DOMAIN.
+	* NEWS: Mention new 'info modules' command.
+
 2019-10-31  Philippe Waroquiers  <philippe.waroquiers@skynet.be>
 
 	* NEWS: Mention $_gdb_setting, $_gdb_setting_str, $_gdb_maint_setting
diff --git a/gdb/NEWS b/gdb/NEWS
index ef21b5d..d46f709 100644
--- a/gdb/NEWS
+++ b/gdb/NEWS
@@ -159,6 +159,10 @@ show print frame-info
   'frame', 'stepi'.  The python frame filtering also respect this setting.
   The 'backtrace' '-frame-info' option can override this global setting.
 
+info modules [-q] [REGEXP]
+  Return a list of Fortran modules matching REGEXP, or all modules if
+  no REGEXP is given.
+
 * Changed commands
 
 help
diff --git a/gdb/doc/ChangeLog b/gdb/doc/ChangeLog
index 4d3f755..52497a1 100644
--- a/gdb/doc/ChangeLog
+++ b/gdb/doc/ChangeLog
@@ -1,3 +1,7 @@
+2019-10-31  Andrew Burgess  <andrew.burgess@embecosm.com>
+
+	* gdb.texinfo (Symbols): Document new 'info modules' command.
+
 2019-10-31  Philippe Waroquiers  <philippe.waroquiers@skynet.be>
 
 	* gdb.texinfo (Convenience Funs): Document the new
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index 7cf4141..ee06df2 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -18886,6 +18886,16 @@ If both @var{regexp} and @var{type_regexp} are provided, an argument
 is printed only if its name matches @var{regexp} and its type matches
 @var{type_regexp}.
 
+@kindex info modules
+@cindex modules
+@item info modules @r{[}-q@r{]} @r{[}@var{regexp}@r{]}
+List all Fortran modules in the program, or all modules matching the
+optional regular expression @var{regexp}.
+
+The optional flag @samp{-q}, which stands for @samp{quiet}, disables
+printing header information and messages explaining why no modules
+have been printed.
+
 @kindex info classes
 @cindex Objective-C, classes and selectors
 @item info classes
diff --git a/gdb/dwarf2read.c b/gdb/dwarf2read.c
index cac719a..0a7a033 100644
--- a/gdb/dwarf2read.c
+++ b/gdb/dwarf2read.c
@@ -4042,6 +4042,10 @@ dw2_symtab_iter_next (struct dw2_symtab_iterator *iter)
 	      if (symbol_kind != GDB_INDEX_SYMBOL_KIND_OTHER)
 		continue;
 	      break;
+	    case MODULE_DOMAIN:
+	      if (symbol_kind != GDB_INDEX_SYMBOL_KIND_OTHER)
+		continue;
+	      break;
 	    default:
 	      break;
 	    }
@@ -5064,6 +5068,10 @@ dw2_expand_marked_cus
 	      if (symbol_kind != GDB_INDEX_SYMBOL_KIND_TYPE)
 		continue;
 	      break;
+	    case MODULES_DOMAIN:
+	      if (symbol_kind != GDB_INDEX_SYMBOL_KIND_OTHER)
+		continue;
+	      break;
 	    default:
 	      break;
 	    }
@@ -5970,6 +5978,15 @@ dw2_debug_names_iterator::next ()
 	  goto again;
 	}
       break;
+    case MODULE_DOMAIN:
+      switch (indexval.dwarf_tag)
+	{
+	case DW_TAG_module:
+	  break;
+	default:
+	  goto again;
+	}
+      break;
     default:
       break;
     }
@@ -6006,6 +6023,14 @@ dw2_debug_names_iterator::next ()
 	  goto again;
 	}
       break;
+    case MODULES_DOMAIN:
+      switch (indexval.dwarf_tag)
+	{
+	case DW_TAG_module:
+	  break;
+	default:
+	  goto again;
+	}
     default:
       break;
     }
@@ -8733,7 +8758,8 @@ scan_partial_symbols (struct partial_die_info *first_die, CORE_ADDR *lowpc,
 	      add_partial_namespace (pdi, lowpc, highpc, set_addrmap, cu);
 	      break;
 	    case DW_TAG_module:
-	      add_partial_module (pdi, lowpc, highpc, set_addrmap, cu);
+	      if (!pdi->is_declaration)
+		add_partial_module (pdi, lowpc, highpc, set_addrmap, cu);
 	      break;
 	    case DW_TAG_imported_unit:
 	      {
diff --git a/gdb/psymtab.c b/gdb/psymtab.c
index b30d29e..df10a75 100644
--- a/gdb/psymtab.c
+++ b/gdb/psymtab.c
@@ -1272,6 +1272,8 @@ recursively_search_psymtabs
 	  QUIT;
 
 	  if ((domain == ALL_DOMAIN
+	       || (domain == MODULES_DOMAIN
+		   && (*psym)->domain == MODULE_DOMAIN)
 	       || (domain == VARIABLES_DOMAIN
 		   && (*psym)->aclass != LOC_TYPEDEF
 		   && (*psym)->aclass != LOC_BLOCK)
diff --git a/gdb/symtab.c b/gdb/symtab.c
index 060e676..4c14eda 100644
--- a/gdb/symtab.c
+++ b/gdb/symtab.c
@@ -299,6 +299,7 @@ search_domain_name (enum search_domain e)
     case VARIABLES_DOMAIN: return "VARIABLES_DOMAIN";
     case FUNCTIONS_DOMAIN: return "FUNCTIONS_DOMAIN";
     case TYPES_DOMAIN: return "TYPES_DOMAIN";
+    case MODULES_DOMAIN: return "MODULES_DOMAIN";
     case ALL_DOMAIN: return "ALL_DOMAIN";
     default: gdb_assert_not_reached ("bad search_domain");
     }
@@ -4482,7 +4483,7 @@ search_symbols (const char *regexp, enum search_domain kind,
   gdb::optional<compiled_regex> preg;
   gdb::optional<compiled_regex> treg;
 
-  gdb_assert (kind <= TYPES_DOMAIN);
+  gdb_assert (kind != ALL_DOMAIN);
 
   ourtype = types[kind];
   ourtype2 = types2[kind];
@@ -4656,7 +4657,10 @@ search_symbols (const char *regexp, enum search_domain kind,
 								     sym)))
 			      || (kind == TYPES_DOMAIN
 				  && SYMBOL_CLASS (sym) == LOC_TYPEDEF
-				  && SYMBOL_DOMAIN (sym) != MODULE_DOMAIN))))
+				  && SYMBOL_DOMAIN (sym) != MODULE_DOMAIN)
+			      || (kind == MODULES_DOMAIN
+				  && SYMBOL_DOMAIN (sym) == MODULE_DOMAIN
+				  && SYMBOL_LINE (sym) != 0))))
 		    {
 		      /* match */
 		      result.emplace_back (i, sym);
@@ -4787,6 +4791,11 @@ print_symbol_info (enum search_domain kind,
 
       printf_filtered (";\n");
     }
+  /* Printing of modules is currently done here, maybe at some future
+     point we might want a language specific method to print the module
+     symbol so that we can customise the output more.  */
+  else if (kind == MODULES_DOMAIN)
+    printf_filtered ("%s\n", SYMBOL_PRINT_NAME (sym));
 }
 
 /* This help function for symtab_symbol_info() prints information
@@ -4827,11 +4836,11 @@ symtab_symbol_info (bool quiet, bool exclude_minsyms,
 		    const char *t_regexp, int from_tty)
 {
   static const char * const classnames[] =
-    {"variable", "function", "type"};
+    {"variable", "function", "type", "module"};
   const char *last_filename = "";
   int first = 1;
 
-  gdb_assert (kind <= TYPES_DOMAIN);
+  gdb_assert (kind != ALL_DOMAIN);
 
   if (regexp != nullptr && *regexp == '\0')
     regexp = nullptr;
@@ -5050,6 +5059,22 @@ info_types_command_completer (struct cmd_list_element *ignore,
   symbol_completer (ignore, tracker, text, word);
 }
 
+/* Implement the 'info modules' command.  */
+
+static void
+info_modules_command (const char *args, int from_tty)
+{
+  info_types_options opts;
+
+  auto grp = make_info_types_options_def_group (&opts);
+  gdb::option::process_options
+    (&args, gdb::option::PROCESS_OPTIONS_UNKNOWN_IS_OPERAND, grp);
+  if (args != nullptr && *args == '\0')
+    args = nullptr;
+  symtab_symbol_info (opts.quiet, true, args, MODULES_DOMAIN, NULL,
+		      from_tty);
+}
+
 /* Breakpoint all functions matching regular expression.  */
 
 void
@@ -6373,6 +6398,10 @@ Options:\n\
   c = add_info ("sources", info_sources_command, info_sources_help.c_str ());
   set_cmd_completer_handle_brkchars (c, info_sources_command_completer);
 
+  c = add_info ("modules", info_modules_command,
+		_("All module names, or those matching REGEXP."));
+  set_cmd_completer_handle_brkchars (c, info_types_command_completer);
+
   add_com ("rbreak", class_breakpoint, rbreak_command,
 	   _("Set a breakpoint for all functions matching REGEXP."));
 
diff --git a/gdb/symtab.h b/gdb/symtab.h
index 20c11d1..72d1c7f 100644
--- a/gdb/symtab.h
+++ b/gdb/symtab.h
@@ -831,8 +831,11 @@ enum search_domain
   /* All defined types */
   TYPES_DOMAIN = 2,
 
+  /* All modules.  */
+  MODULES_DOMAIN = 3,
+
   /* Any type.  */
-  ALL_DOMAIN = 3
+  ALL_DOMAIN = 4
 };
 
 extern const char *search_domain_name (enum search_domain);
diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index 510a1e0..6514c07 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,10 @@
+2019-10-31  Andrew Burgess  <andrew.burgess@embecosm.com>
+
+	* gdb.fortran/info-modules.exp: New file.
+	* gdb.fortran/info-types.exp: Build with new file.
+	* gdb.fortran/info-types.f90: Include and use new module.
+	* gdb.fortran/info-types-2.f90: New file.
+
 2019-10-31  Philippe Waroquiers  <philippe.waroquiers@skynet.be>
 
 	* gdb.base/setshow.exp: Test $_gdb_setting and $_gdb_setting_str.
diff --git a/gdb/testsuite/gdb.fortran/info-modules.exp b/gdb/testsuite/gdb.fortran/info-modules.exp
new file mode 100644
index 0000000..f961d28
--- /dev/null
+++ b/gdb/testsuite/gdb.fortran/info-modules.exp
@@ -0,0 +1,66 @@
+# Copyright 2019 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/>.
+
+# This file tests 'info modules'.
+
+load_lib "fortran.exp"
+
+if { [skip_fortran_tests] } { continue }
+
+standard_testfile info-types.f90 info-types-2.f90
+
+if { [prepare_for_testing "failed to prepare" $testfile \
+	  [list $srcfile $srcfile2] {debug f90}] } {
+    return -1
+}
+
+if { ![runto MAIN__] } {
+    perror "Could not run to breakpoint `MAIN__'."
+    continue
+}
+
+gdb_test "info modules" \
+    [multi_line \
+	 "All defined modules:" \
+	 "" \
+	 "File .*${srcfile2}:" \
+	 "18:\[\t \]+mod2" \
+	 "" \
+	 "File .*${srcfile}:" \
+	 "16:\[\t \]+mod1" ]
+
+gdb_test "info modules 1" \
+    [multi_line \
+	 "All modules matching regular expression \"1\":" \
+	 "" \
+	 "File .*${srcfile}:" \
+	 "16:\[\t \]+mod1" ]
+
+gdb_test "info modules 2" \
+    [multi_line \
+	 "All modules matching regular expression \"2\":" \
+	 "" \
+	 "File .*${srcfile2}:" \
+	 "18:\[\t \]+mod2" ]
+
+gdb_test "info modules mod" \
+    [multi_line \
+	 "All modules matching regular expression \"mod\":" \
+	 "" \
+	 "File .*${srcfile2}:" \
+	 "18:\[\t \]+mod2" \
+	 "" \
+	 "File .*${srcfile}:" \
+	 "16:\[\t \]+mod1" ]
diff --git a/gdb/testsuite/gdb.fortran/info-types-2.f90 b/gdb/testsuite/gdb.fortran/info-types-2.f90
new file mode 100644
index 0000000..a404418
--- /dev/null
+++ b/gdb/testsuite/gdb.fortran/info-types-2.f90
@@ -0,0 +1,20 @@
+! Copyright 2019 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 2 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/>.
+
+! Comment just to change the line number on which
+! mod2 is defined.
+module mod2
+  integer :: mod2_var_1 = 123
+end module mod2
diff --git a/gdb/testsuite/gdb.fortran/info-types.exp b/gdb/testsuite/gdb.fortran/info-types.exp
index 3064628..954e083 100644
--- a/gdb/testsuite/gdb.fortran/info-types.exp
+++ b/gdb/testsuite/gdb.fortran/info-types.exp
@@ -19,9 +19,10 @@ load_lib "fortran.exp"
 
 if { [skip_fortran_tests] } { continue }
 
-standard_testfile .f90
+standard_testfile info-types.f90 info-types-2.f90
 
-if { [prepare_for_testing "failed to prepare" $testfile $srcfile {debug f90}] } {
+if { [prepare_for_testing "failed to prepare" $testfile \
+	  [list $srcfile2 $srcfile] {debug f90}] } {
     return -1
 }
 
diff --git a/gdb/testsuite/gdb.fortran/info-types.f90 b/gdb/testsuite/gdb.fortran/info-types.f90
index 0e27e1d..ec52ef9 100644
--- a/gdb/testsuite/gdb.fortran/info-types.f90
+++ b/gdb/testsuite/gdb.fortran/info-types.f90
@@ -21,6 +21,7 @@ end module mod1
 
 program info_types_test
   use mod1
+  use mod2
 
   type :: s1
      integer :: a
@@ -30,7 +31,7 @@ program info_types_test
   type (s1) :: var_a
   type (m1t1) :: var_b
 
-  var_a%a = 1
+  var_a%a = 1 + mod2_var_1
   var_b%b = 2
   l = .FALSE.
 end program info_types_test