http://sourceware.org/ml/gdb-patches/2014-08/msg00025.html
Subject: [patch 1/2] Re: Crash regression(?) printing Fortran strings in bt  [Re: [V2 00/23] Fortran dynamic array support]


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On Fri, 01 Aug 2014 09:20:19 +0200, Keven Boell wrote:
> I just tried it on Fedora 20 i686.  Applied the patch, you mentioned, on top of
> the Fortran VLA series and executed your dynamic-other-frame test.  Everything
> is working fine here, I cannot reproduce the crash.

I have it reproducible on Fedora 20 i686 with plain
CFLAGS=-g ./configure;make;cd gdb/testsuite;make site.exp;runtest gdb.fortran/dynamic-other-frame.exp

Besides that I have updated the testcase with
	gdb_test_no_output "set print frame-arguments all"
so that there is no longer needed the patch:
	[patch] Display Fortran strings in backtraces
	https://sourceware.org/ml/gdb-patches/2014-07/msg00709.html

The fix below has no regressions for me.  Unfortunately I do not see why you
cannot reproduce it.


Thanks,
Jan

--- ./gdb/dwarf2loc.c	2016-08-29 04:01:25.000000000 +0200
+++ ./gdb/dwarf2loc.c	2016-09-01 11:00:20.258909494 +0200
@@ -2289,6 +2289,15 @@ const struct dwarf_expr_context_funcs dw
   dwarf_expr_get_obj_addr
 };
 
+static void
+select_frame_cleanup (void *arg)
+{
+  struct frame_info *frame = (struct frame_info *) arg;
+
+  if (frame != NULL)
+    select_frame (frame);
+}
+
 /* Evaluate a location description, starting at DATA and with length
    SIZE, to find the current location of variable of TYPE in the
    context of FRAME.  BYTE_OFFSET is applied after the contents are
@@ -2318,6 +2327,11 @@ dwarf2_evaluate_loc_desc_full (struct ty
 
   ctx = new_dwarf_expr_context ();
   old_chain = make_cleanup_free_dwarf_expr_context (ctx);
+
+  make_cleanup (select_frame_cleanup, deprecated_safe_get_selected_frame ());
+  if (frame != NULL)
+    select_frame (frame);
+
   value_chain = make_cleanup_value_free_to_mark (value_mark ());
 
   ctx->gdbarch = get_objfile_arch (objfile);
Index: gdb-7.9.50.20150520/gdb/testsuite/gdb.fortran/dynamic-other-frame-stub.f90
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ gdb-7.9.50.20150520/gdb/testsuite/gdb.fortran/dynamic-other-frame-stub.f90	2015-05-31 16:14:05.844545344 +0200
@@ -0,0 +1,24 @@
+! Copyright 2010 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, write to the Free Software
+! Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+!
+! Ihis file is the Fortran source file for dynamic.exp.
+! Original file written by Jakub Jelinek <jakub@redhat.com>.
+! Modified for the GDB testcase by Jan Kratochvil <jan.kratochvil@redhat.com>.
+
+subroutine bar
+  real :: dummy
+  dummy = 1
+end subroutine bar
Index: gdb-7.9.50.20150520/gdb/testsuite/gdb.fortran/dynamic-other-frame.exp
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ gdb-7.9.50.20150520/gdb/testsuite/gdb.fortran/dynamic-other-frame.exp	2015-05-31 16:14:05.845545351 +0200
@@ -0,0 +1,39 @@
+# Copyright 2010 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, write to the Free Software
+# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  
+
+set testfile "dynamic-other-frame"
+set srcfile1 ${testfile}.f90
+set srcfile2 ${testfile}-stub.f90
+set objfile2 [standard_output_file ${testfile}-stub.o]
+set executable ${testfile}
+set binfile [standard_output_file ${executable}]
+
+if { [gdb_compile "${srcdir}/${subdir}/${srcfile2}" "${objfile2}" object {f90}] != ""
+     || [gdb_compile "${srcdir}/${subdir}/${srcfile1} ${objfile2}" "${binfile}" executable {debug f90}] != "" } {
+    untested "Couldn't compile ${srcfile1} or ${srcfile2}"
+    return -1
+}
+
+clean_restart ${executable}
+
+gdb_test_no_output "set print frame-arguments all"
+
+if ![runto bar_] then {
+    perror "couldn't run to bar_"
+    continue
+}
+
+gdb_test "bt" {foo \(string='hello'.*}
Index: gdb-7.9.50.20150520/gdb/testsuite/gdb.fortran/dynamic-other-frame.f90
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ gdb-7.9.50.20150520/gdb/testsuite/gdb.fortran/dynamic-other-frame.f90	2015-05-31 16:14:05.845545351 +0200
@@ -0,0 +1,36 @@
+! Copyright 2010 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, write to the Free Software
+! Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+!
+! Ihis file is the Fortran source file for dynamic.exp.
+! Original file written by Jakub Jelinek <jakub@redhat.com>.
+! Modified for the GDB testcase by Jan Kratochvil <jan.kratochvil@redhat.com>.
+
+subroutine foo (string)
+  interface
+    subroutine bar
+    end subroutine
+  end interface
+  character string*(*)
+  call bar                                ! stop-here
+end subroutine foo
+program test
+  interface
+    subroutine foo (string)
+    character string*(*)
+    end subroutine
+  end interface
+  call foo ('hello')
+end