[PATCH v2 1/7] DWARF: Don't add nameless modules to partial symbol table.

[Pawel Wodkowski <pwodkowski@pl.sii.eu>]

From: Bernhard Heckel <bernhard.heckel@intel.com>

A name for BLOCK DATA in Fortran is optional. If no
name has been assigned, GDB will crash during read-in of DWARF
when BLOCK DATA is represented via DW_TAG_module.
BLOCK DATA is used for one-time initialization of
non-pointer variables in named common blocks.

2016-06-15  Bernhard Heckel  <bernhard.heckel@intel.com>

gdb/Changelog:
	* dwarf2read.c (add_partial_symbol): Skip nameless modules.

gdb/Testsuite/Changelog:
	* gdb.fortran/block-data.f: New.
	* gdb.fortran/block-data.exp: New.
---
 gdb/dwarf2read.c                         | 13 ++++---
 gdb/testsuite/gdb.fortran/block-data.exp | 51 ++++++++++++++++++++++++++++
 gdb/testsuite/gdb.fortran/block-data.f   | 58 ++++++++++++++++++++++++++++++++
 3 files changed, 117 insertions(+), 5 deletions(-)
 create mode 100644 gdb/testsuite/gdb.fortran/block-data.exp
 create mode 100644 gdb/testsuite/gdb.fortran/block-data.f

diff --git a/gdb/dwarf2read.c b/gdb/dwarf2read.c
index d2a8cd44f9a5..89fd4ae15e80 100644
--- a/gdb/dwarf2read.c
+++ b/gdb/dwarf2read.c
@@ -8995,11 +8995,14 @@ add_partial_symbol (struct partial_die_info *pdi, struct dwarf2_cu *cu)
 			   0, cu->language, objfile);
       break;
     case DW_TAG_module:
-      add_psymbol_to_list (actual_name, strlen (actual_name),
-			   built_actual_name != NULL,
-			   MODULE_DOMAIN, LOC_TYPEDEF, -1,
-			   &objfile->global_psymbols,
-			   0, cu->language, objfile);
+      /* In Fortran 77 there might be a "BLOCK DATA" module available wihout
+         any name. If so, we skip the module as it doesn't bring any value */
+      if (actual_name != nullptr)
+	add_psymbol_to_list (actual_name, strlen (actual_name),
+			     built_actual_name != nullptr,
+			     MODULE_DOMAIN, LOC_TYPEDEF, -1,
+			     &objfile->global_psymbols,
+			     0, cu->language, objfile);
       break;
     case DW_TAG_class_type:
     case DW_TAG_interface_type:
diff --git a/gdb/testsuite/gdb.fortran/block-data.exp b/gdb/testsuite/gdb.fortran/block-data.exp
new file mode 100644
index 000000000000..2af250ad3886
--- /dev/null
+++ b/gdb/testsuite/gdb.fortran/block-data.exp
@@ -0,0 +1,51 @@
+# Copyright 2018 Free Software Foundation, Inc.
+#
+# Contributed by Intel Corp. <bernhard.heckel@intel.com>
+#
+# 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 test is supposed to test anonymous block-data statement.
+
+if { [skip_fortran_tests] } { return -1 }
+
+standard_testfile .f
+load_lib "fortran.exp"
+
+if {[prepare_for_testing $testfile.exp $testfile $srcfile {debug f90}]} {
+    return -1
+}
+
+if ![runto MAIN__] then {
+    untested "couldn't run to breakpoint MAIN__"
+    return -1
+}
+
+gdb_test "print doub1" "= 1.11\\d+" "print doub1, default values"
+gdb_test "print doub2" "= 2.22\\d+" "print doub2, default values"
+gdb_test "print char1" "= 'abcdef'" "print char1, default values"
+gdb_test "print char2" "= 'ghijkl'" "print char2, default values"
+
+gdb_breakpoint [gdb_get_line_number "! BP_BEFORE_SUB"]
+gdb_continue_to_breakpoint "! BP_BEFORE_SUB" ".*! BP_BEFORE_SUB.*"
+gdb_test "print doub1" "= 11.11\\d+" "print doub1, before sub"
+gdb_test "print doub2" "= 22.22\\d+" "print doub2, before sub"
+gdb_test "print char1" "= 'ABCDEF'" "print char1, before sub"
+gdb_test "print char2" "= 'GHIJKL'" "print char2, before sub"
+
+gdb_breakpoint [gdb_get_line_number "! BP_SUB"]
+gdb_continue_to_breakpoint "! BP_SUB" ".*! BP_SUB.*"
+gdb_test "print doub1" "= 11.11\\d+" "print char1, in sub"
+gdb_test "print doub2" "= 22.22\\d+" "print doub2, in sub"
+gdb_test "print char1" "= 'ABCDEF'" "print char1, in sub"
+gdb_test "print char2" "= 'GHIJKL'" "print char2, in sub"
diff --git a/gdb/testsuite/gdb.fortran/block-data.f b/gdb/testsuite/gdb.fortran/block-data.f
new file mode 100644
index 000000000000..a28e687ec885
--- /dev/null
+++ b/gdb/testsuite/gdb.fortran/block-data.f
@@ -0,0 +1,58 @@
+! Copyright 2018 Free Software Foundation, Inc.
+!
+! Contributed by Intel Corp. <bernhard.heckel@intel.com>
+!
+! 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 if GDB can handle block data without global name
+!
+! MAIN
+        PROGRAM bdata
+        DOUBLE PRECISION doub1, doub2
+        CHARACTER*6 char1, char2
+
+        COMMON /BLK1/ doub1, char1
+        COMMON /BLK2/ doub2, char2
+
+        doub1 = 11.111
+        doub2 = 22.222
+        char1 = 'ABCDEF'
+        char2 = 'GHIJKL'
+        CALL sub_block_data      ! BP_BEFORE_SUB
+        STOP
+        END
+
+! BLOCK DATA
+        BLOCK DATA
+
+        DOUBLE PRECISION doub1, doub2
+        CHARACTER*6 char1, char2
+
+        COMMON /BLK1/ doub1, char1
+        COMMON /BLK2/ doub2, char2
+        DATA doub1, doub2 /1.111, 2.222/
+        DATA char1, char2 /'abcdef', 'ghijkl'/
+        END
+
+! SUBROUTINE
+        SUBROUTINE sub_block_data
+
+        DOUBLE PRECISION doub1, doub2
+        CHARACTER*6 char1, char2
+
+        COMMON /BLK1/ doub1, char1
+        COMMON /BLK2/ doub2, char2
+
+        char1 = char2;    ! BP_SUB
+        END
-- 
2.7.4