[PATCHv2 3/4] gdb/fortran: Add new 'info modules' command

[Andrew Burgess <andrew.burgess@embecosm.com>]

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.
	* psymtab.c (recursively_search_psymtabs): Likewise.
	* 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: Update expected results.
	* gdb.fortran/info-types.f90: Extend with extra module.
---
 gdb/ChangeLog                              | 16 ++++++++
 gdb/NEWS                                   |  4 ++
 gdb/doc/ChangeLog                          |  4 ++
 gdb/doc/gdb.texinfo                        | 10 +++++
 gdb/dwarf2read.c                           | 25 ++++++++++++
 gdb/psymtab.c                              |  2 +
 gdb/symtab.c                               | 36 ++++++++++++++++--
 gdb/symtab.h                               |  5 ++-
 gdb/testsuite/ChangeLog                    |  6 +++
 gdb/testsuite/gdb.fortran/info-modules.exp | 61 ++++++++++++++++++++++++++++++
 gdb/testsuite/gdb.fortran/info-types.exp   |  2 +-
 gdb/testsuite/gdb.fortran/info-types.f90   |  5 +++
 12 files changed, 170 insertions(+), 6 deletions(-)
 create mode 100644 gdb/testsuite/gdb.fortran/info-modules.exp

diff --git a/gdb/NEWS b/gdb/NEWS
index 3211ec9542c..2347c14d37d 100644
--- a/gdb/NEWS
+++ b/gdb/NEWS
@@ -138,6 +138,10 @@ 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/gdb.texinfo b/gdb/doc/gdb.texinfo
index 78d38284693..17e2c4cce71 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -18780,6 +18780,16 @@
 is printed only if its name matches @var{regexp} and its type matches
 @var{type_regexp}.
 
+@kindex info modules
+@cindex modules
+@item info modules [-q] [@var{regexp}]
+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 9d9dd6db709..c7b3a90042f 100644
--- a/gdb/dwarf2read.c
+++ b/gdb/dwarf2read.c
@@ -4025,6 +4025,10 @@ 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;
 	    }
@@ -5047,6 +5051,10 @@ 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;
 	    }
@@ -5953,6 +5961,15 @@ 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;
     }
@@ -5989,6 +6006,14 @@ 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;
     }
diff --git a/gdb/psymtab.c b/gdb/psymtab.c
index 31b6d597773..44af8031fc4 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 8a551f1575a..27db03089d2 100644
--- a/gdb/symtab.c
+++ b/gdb/symtab.c
@@ -297,6 +297,7 @@ 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");
     }
@@ -4474,7 +4475,7 @@ 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 <= MODULES_DOMAIN);
 
   ourtype = types[kind];
   ourtype2 = types2[kind];
@@ -4648,7 +4649,9 @@ 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))))
 		    {
 		      /* match */
 		      result.emplace_back (i, sym);
@@ -4779,6 +4782,11 @@ 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
@@ -4819,11 +4827,11 @@ 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 <= MODULES_DOMAIN);
 
   if (regexp != nullptr && *regexp == '\0')
     regexp = nullptr;
@@ -5042,6 +5050,22 @@ 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
@@ -6365,6 +6389,10 @@ 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 dc65409dd24..ba8df9191ff 100644
--- a/gdb/symtab.h
+++ b/gdb/symtab.h
@@ -829,8 +829,11 @@ 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/gdb.fortran/info-modules.exp b/gdb/testsuite/gdb.fortran/info-modules.exp
new file mode 100644
index 00000000000..33110236271
--- /dev/null
+++ b/gdb/testsuite/gdb.fortran/info-modules.exp
@@ -0,0 +1,61 @@
+# 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
+
+if { [prepare_for_testing "failed to prepare" $testfile $srcfile {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 .*:" \
+	 "16:\[\t \]+mod1" \
+	 "22:\[\t \]+mod2" ]
+
+gdb_test "info modules 1" \
+    [multi_line \
+	 "All modules matching regular expression \"1\":" \
+	 "" \
+	 "File .*:" \
+	 "16:\[\t \]+mod1" ]
+
+gdb_test "info modules 2" \
+    [multi_line \
+	 "All modules matching regular expression \"2\":" \
+	 "" \
+	 "File .*:" \
+	 "22:\[\t \]+mod2" ]
+
+gdb_test "info modules mod" \
+    [multi_line \
+	 "All modules matching regular expression \"mod\":" \
+	 "" \
+	 "File .*:" \
+	 "16:\[\t \]+mod1" \
+	 "22:\[\t \]+mod2" ]
diff --git a/gdb/testsuite/gdb.fortran/info-types.exp b/gdb/testsuite/gdb.fortran/info-types.exp
index 30646287ee9..efaf4e57368 100644
--- a/gdb/testsuite/gdb.fortran/info-types.exp
+++ b/gdb/testsuite/gdb.fortran/info-types.exp
@@ -46,5 +46,5 @@ gdb_test "info types" \
 	 ")?\[\t \]+${logical4}" \
 	 "(20:\[\t \]+Type __vtype_mod1_M1t1;" \
 	 ")?$decimal:\[\t \]+Type m1t1;" \
-	 "22:\[\t \]+Type s1;(" \
+	 "26:\[\t \]+Type s1;(" \
 	 ".*)?"]
diff --git a/gdb/testsuite/gdb.fortran/info-types.f90 b/gdb/testsuite/gdb.fortran/info-types.f90
index 0e27e1ddf08..859a9485c8f 100644
--- a/gdb/testsuite/gdb.fortran/info-types.f90
+++ b/gdb/testsuite/gdb.fortran/info-types.f90
@@ -19,8 +19,13 @@ module mod1
   end type m1t1
 end module mod1
 
+module mod2
+  integer :: mod2_var_1 = 123
+end module mod2
+
 program info_types_test
   use mod1
+  use mod2
 
   type :: s1
      integer :: a
-- 
2.14.5