[expr-cumulative] Fix namespace regression for G++-4.1

[Jan Kratochvil <jan dot kratochvil at redhat dot com>]

Hi,

this patch was discussed here before:
	Re: [patch by Michael Matz] Re: archer gdb and gcc 4.1 global namespaceDIE
	http://sourceware.org/ml/archer/2009-q2/msg00094.html

but the code is not present in current archer-keiths-expr-cumulative and thus
this branch regresses on the testcase against FSF GDB.

On G++-4.1 code it creates GDB symbol "::::var".

It is also not present in any of the branches merged in
archer-jankratochvil-fedora12.

OK to check it in archer-keiths-expr-cumulative?


Thanks,
Jan


gdb/
2009-12-20  Jan Kratochvil  <jan.kratochvil@redhat.com>

	Fix compatibility with G++-4.1.
	* dwarf2read.c (partial_die_parent_scope): New variable PARENT_NAME.
	Ignore parent namespaces with name "::".
	(physname_prefix_1): Ignore namespaces with name "::".

gdb/testsuite/
2009-12-20  Jan Kratochvil  <jan.kratochvil@redhat.com>

	* gdb.dwarf2/dw2-empty-namespace.exp, gdb.dwarf2/dw2-empty-namespace.S:
	New.

--- a/gdb/dwarf2read.c
+++ b/gdb/dwarf2read.c
@@ -2355,11 +2355,18 @@ partial_die_parent_scope (struct partial_die_info *pdi,
       || parent->tag == DW_TAG_interface_type
       || parent->tag == DW_TAG_union_type)
     {
+      char *parent_name = parent->name;
+
+      /* G++ 4.1 produced DW_TAG_namespace with DW_AT_name "::".  */
+      if (parent->tag == DW_TAG_namespace && parent_name != NULL
+          && strcmp (parent_name, "::") == 0)
+	parent_name = NULL;
+
       if (grandparent_scope == NULL)
-	parent->scope = parent->name;
+	parent->scope = parent_name;
       else
 	parent->scope = typename_concat (&cu->comp_unit_obstack, grandparent_scope,
-					 parent->name, cu);
+					 parent_name, cu);
     }
   else if (parent->tag == DW_TAG_enumeration_type)
     /* Enumerators should not get the name of the enumeration as a prefix.  */
@@ -9008,6 +9015,9 @@ physname_prefix_1 (struct ui_file *buf, struct die_info *die,
 	  name = dwarf2_name (die, cu);
 	  if (name == NULL)
 	    name = "(anonymous namespace)";
+	  /* G++ 4.1 produced DW_TAG_namespace with DW_AT_name "::".  */
+	  else if (strcmp (name, "::") == 0)
+	    name = NULL;
 	  break;
 
 	case DW_TAG_class_type:
--- /dev/null
+++ b/gdb/testsuite/gdb.dwarf2/dw2-empty-namespace.S
@@ -0,0 +1,108 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2009 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 G++ 4.1 producing DW_TAG_namespace with DW_AT_name "::".  */
+
+	.data
+var:	.4byte	1
+
+	.section .debug_info
+.Lcu1_begin:
+	/* CU header */
+	.4byte	.Lcu1_end - .Lcu1_start		/* Length of Compilation Unit */
+.Lcu1_start:
+	.2byte	2				/* DWARF Version */
+	.4byte	.Labbrev1_begin			/* Offset into abbrev section */
+	.byte	4				/* Pointer size */
+
+	/* CU die */
+	.uleb128 1				/* Abbrev: DW_TAG_compile_unit */
+	.ascii	"file1.txt\0"			/* DW_AT_name */
+	.ascii	"GNU C 3.3.3\0"			/* DW_AT_producer */
+	.byte	4				/* DW_LANG_C_plus_plus (C++) */
+
+.Ltype_int:
+	.uleb128	2			/* Abbrev: DW_TAG_base_type */
+	.ascii		"int\0"			/* DW_AT_name */
+	.byte		4			/* DW_AT_byte_size */
+	.byte		5			/* DW_AT_encoding */
+
+	.uleb128	3			/* Abbrev: DW_TAG_namespace */
+	.ascii		"::\0"			/* DW_AT_name */
+
+	.uleb128	7			/* Abbrev: DW_TAG_variable (location) */
+	.ascii		"var\0"			/* DW_AT_name */
+	.byte		2f - 1f			/* DW_AT_location */
+1:	.byte		3			/*   DW_OP_addr */
+	.4byte		var			/*   <addr> */
+2:	.4byte		.Ltype_int-.Lcu1_begin	/* DW_AT_type */
+
+	.byte		0			/* End of children of DW_TAG_namespace */
+
+	.byte		0			/* End of children of CU */
+
+.Lcu1_end:
+
+/* Abbrev table */
+	.section .debug_abbrev
+.Labbrev1_begin:
+	.uleb128	1			/* Abbrev code */
+	.uleb128	0x11			/* DW_TAG_compile_unit */
+	.byte		1			/* has_children */
+	.uleb128	0x3			/* DW_AT_name */
+	.uleb128	0x8			/* DW_FORM_string */
+	.uleb128	0x25			/* DW_AT_producer */
+	.uleb128	0x8			/* DW_FORM_string */
+	.uleb128	0x13			/* DW_AT_language */
+	.uleb128	0xb			/* DW_FORM_data1 */
+	.byte		0x0			/* Terminator */
+	.byte		0x0			/* Terminator */
+
+	.uleb128	2			/* Abbrev code */
+	.uleb128	0x24			/* DW_TAG_base_type */
+	.byte		0			/* has_children */
+	.uleb128	0x3			/* DW_AT_name */
+	.uleb128	0x8			/* DW_FORM_string */
+	.uleb128	0xb			/* DW_AT_byte_size */
+	.uleb128	0xb			/* DW_FORM_data1 */
+	.uleb128	0x3e			/* DW_AT_encoding */
+	.uleb128	0xb			/* DW_FORM_data1 */
+	.byte		0x0			/* Terminator */
+	.byte		0x0			/* Terminator */
+
+	.uleb128	3			/* Abbrev code */
+	.uleb128	0x39			/* DW_TAG_namespace */
+	.byte		1			/* has_children */
+	.uleb128	0x3			/* DW_AT_name */
+	.uleb128	0x8			/* DW_FORM_string */
+	.byte		0x0			/* Terminator */
+	.byte		0x0			/* Terminator */
+
+	.uleb128	7			/* Abbrev code (location) */
+	.uleb128	0x34			/* DW_TAG_variable */
+	.byte		0			/* has_children */
+	.uleb128	0x3			/* DW_AT_name */
+	.uleb128	0x8			/* DW_FORM_string */
+	.uleb128	0x2			/* DW_AT_location */
+	.uleb128	0xa			/* DW_FORM_block1 */
+	.uleb128	0x49			/* DW_AT_type */
+	.uleb128	0x13			/* DW_FORM_ref4 */
+	.byte		0x0			/* Terminator */
+	.byte		0x0			/* Terminator */
+
+	.byte		0x0			/* Terminator */
+	.byte		0x0			/* Terminator */
--- /dev/null
+++ b/gdb/testsuite/gdb.dwarf2/dw2-empty-namespace.exp
@@ -0,0 +1,43 @@
+# Copyright 2009 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 G++ 4.1 producing DW_TAG_namespace with DW_AT_name "::".
+
+# This test can only be run on targets which support DWARF-2 and use gas.
+# For now pick a sampling of likely targets.
+if {![istarget *-*-linux*]
+    && ![istarget *-*-gnu*]
+    && ![istarget *-*-elf*]
+    && ![istarget *-*-openbsd*]
+    && ![istarget arm-*-eabi*]
+    && ![istarget powerpc-*-eabi*]} {
+    return 0  
+}
+
+set testfile "dw2-empty-namespace"
+set srcfile ${testfile}.S
+set executable ${testfile}.x
+
+if  { [gdb_compile "${srcdir}/${subdir}/${srcfile}" "${objdir}/${subdir}/${executable}" object {nodebug}] != "" } {
+    return -1
+}
+
+clean_restart $executable
+
+# `p var' below can work without identified DWARF DIE just based on its ELF symbol.
+# Catch it here as `type = <data variable, no debug info>'.
+gdb_test "ptype var" "type = int"
+
+gdb_test "p var" " = 1"