[RFA/dwarf] Anonymous nested function causes SEGV during psymbol read

[RFA/dwarf] Anonymous nested function causes SEGV during psymbol read

[Joel Brobecker]

Hello,

One of the AdaCore engineers reported a GDB crash while debugging
optimized code.  This is the first problem that I found...

According to the DWARF3 standard, a function always has a name attribute
(Section 3.3 - Subroutine and Entry Point Entries).  The only exception
is when a DW_AT_abstract_origin attribute is provided, in which case
the name may be inherited from the referenced DIE.

The problem occured because our compiler generated a subprogram DIE
for a nested function where the name attribute was missing (and no
abstract-origin either).  Our code in add_partial_symbol is not
prepared to deal with the situation, and happily just tries  to compute
the length of the (NULL) function name.

This normally cannot happen, because there is already a guard in
scan_partial_symbols, where we (silently!) ignore anonymous dies,
including anonymous subprograms. Unfortunately, there is a flaw that
affects Ada and other languages that allow nested subprograms. For
nested subprograms, we do not go through scan_partial_symbols and
thus we are missing the name check.

This patch adds the name check in the nested subprogram case.
A complaint was initially added, but then it seemed inconsistent
to emit that complaint for nested subprograms only.  I suggest
we either do not emit them at all, or we emit them for both cases.

One other option that just occurred to me while typing this message is
to still create the partial symbol, but with a dummy name. Something
like "<anonymous>" or "<function-name-missing>".  However, I think we need
to be careful to do the same when creating the associated symbol...
Right now, we simply ignore them:

  /* Ignore functions with missing or empty names and functions with
     missing or invalid low and high pc attributes.  */
  if (name == NULL || !dwarf2_get_pc_bounds (die, &lowpc, &highpc, cu, NULL))
    return;

(and the way things are implemented, this also applies to nested
subprograms).

gdb/ChangeLog:

        * dwarf2read.c (add_partial_subprogram): If the subprogram does not
        have a name, do not create the associated partial symbol.

gdb/testsuite/ChangeLog:

        * gdb.dwarf2/dw2-anonymous-func.S: New file.
        * gdb.dwarf2/dw2-anonymous-func.exp: New testcase.

Tested on x86_64-linux, no regression.  Note that the testcase also
verifies that the psymtab->symtab conversion does not crash (this is
the purpose of the "list file1.txt:1" test.

OK to apply?

Thanks,
-- 
Joel

---
 gdb/dwarf2read.c                                |    5 +-
 gdb/testsuite/gdb.dwarf2/dw2-anonymous-func.S   |  237 +++++++++++++++++++++++
 gdb/testsuite/gdb.dwarf2/dw2-anonymous-func.exp |   53 +++++
 3 files changed, 294 insertions(+), 1 deletions(-)
 create mode 100644 gdb/testsuite/gdb.dwarf2/dw2-anonymous-func.S
 create mode 100644 gdb/testsuite/gdb.dwarf2/dw2-anonymous-func.exp

diff --git a/gdb/dwarf2read.c b/gdb/dwarf2read.c
index a05c946..25de83d 100644
--- a/gdb/dwarf2read.c
+++ b/gdb/dwarf2read.c
@@ -2698,7 +2698,10 @@ add_partial_subprogram (struct partial_die_info *pdi,
 				 pdi->lowpc, pdi->highpc - 1,
 				 cu->per_cu->psymtab);
 	    }
-          if (!pdi->is_declaration)
+	  /* Ignore subprograms that do not have a name.  Such entries
+	     are incorrect, according to the DWARF standard, and we need
+	     a function name to create the associated partial symbol.  */
+	  if (!pdi->is_declaration && pdi->name)
             add_partial_symbol (pdi, cu);
         }
     }
diff --git a/gdb/testsuite/gdb.dwarf2/dw2-anonymous-func.S b/gdb/testsuite/gdb.dwarf2/dw2-anonymous-func.S
new file mode 100644
index 0000000..5db1985
--- /dev/null
+++ b/gdb/testsuite/gdb.dwarf2/dw2-anonymous-func.S
@@ -0,0 +1,237 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2004, 2007, 2008, 2009, 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 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 a minimal file containing DWARF-2 information.  This test also
+   serves as a skeleton for other DWARF-2 tests.  Most other tests will
+   not be this extensively itemized and commented...  */
+
+/* Dummy function to provide debug information for.  */
+
+	.text
+.Lbegin_text1:
+	.globl func_cu1
+	.type func_cu1, %function
+func_cu1:
+.Lbegin_func_cu1:
+	.int 0
+.Lend_func_cu1:
+	.size func_cu1, .-func_cu1
+	.globl func_cu2
+	.type func_cu2, %function
+func_cu2:
+.Lbegin_func_cu2:
+	.int 0
+.Lend_func_cu2:
+	.size func_cu2, .-func_cu2
+.Lend_text1:
+
+/* Debug information */
+
+	.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 */
+	.4byte	.Lline1_begin			/* DW_AT_stmt_list */
+	.4byte	.Lend_text1			/* DW_AT_high_pc */
+	.4byte	.Lbegin_text1			/* DW_AT_low_pc */
+	.ascii	"file1.txt\0"			/* DW_AT_name */
+	.ascii	"GNU C 3.3.3\0"			/* DW_AT_producer */
+	.byte	0x0d				/* DW_AT_language (Ada95) */
+
+	/* func_cu1 */
+	.uleb128	2			/* Abbrev: DW_TAG_subprogram */
+	.byte		1			/* DW_AT_external */
+	.byte		1			/* DW_AT_decl_file */
+	.byte		2			/* DW_AT_decl_line */
+	.ascii		"func_cu1\0"		/* DW_AT_name */
+	.4byte		.Ltype_int-.Lcu1_begin	/* DW_AT_type */
+	.4byte		.Lbegin_func_cu1	/* DW_AT_low_pc */
+	.4byte		.Lend_func_cu1		/* DW_AT_high_pc */
+	.byte		1			/* DW_AT_frame_base: length */
+	.byte		0x55			/* DW_AT_frame_base: DW_OP_reg5 */
+	/* func_cu2 */
+	.uleb128	4			/* Abbrev: DW_TAG_subprogram */
+	.byte		1			/* DW_AT_external */
+	.byte		1			/* DW_AT_decl_file */
+	.byte		2			/* DW_AT_decl_line */
+	.4byte		.Ltype_int-.Lcu1_begin	/* DW_AT_type */
+	.4byte		.Lbegin_func_cu2	/* DW_AT_low_pc */
+	.4byte		.Lend_func_cu2		/* DW_AT_high_pc */
+	.byte		1			/* DW_AT_frame_base: length */
+	.byte		0x55			/* DW_AT_frame_base: DW_OP_reg5 */
+	.byte		0x0			/* End of children of func_cu1 */
+
+.Ltype_int:
+	.uleb128	3			/* Abbrev: DW_TAG_base_type */
+	.ascii		"int\0"			/* DW_AT_name */
+	.byte		4			/* DW_AT_byte_size */
+	.byte		5			/* DW_AT_encoding */
+
+	.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	0x10			/* DW_AT_stmt_list */
+	.uleb128	0x6			/* DW_FORM_data4 */
+	.uleb128	0x12			/* DW_AT_high_pc */
+	.uleb128	0x1			/* DW_FORM_addr */
+	.uleb128	0x11			/* DW_AT_low_pc */
+	.uleb128	0x1			/* DW_FORM_addr */
+	.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	0x2e			/* DW_TAG_subprogram */
+	.byte		1			/* has_children */
+	.uleb128	0x3f			/* DW_AT_external */
+	.uleb128	0xc			/* DW_FORM_flag */
+	.uleb128	0x3a			/* DW_AT_decl_file */
+	.uleb128	0xb			/* DW_FORM_data1 */
+	.uleb128	0x3b			/* DW_AT_decl_line */
+	.uleb128	0xb			/* DW_FORM_data1 */
+	.uleb128	0x3			/* DW_AT_name */
+	.uleb128	0x8			/* DW_FORM_string */
+	.uleb128	0x49			/* DW_AT_type */
+	.uleb128	0x13			/* DW_FORM_ref4 */
+	.uleb128	0x11			/* DW_AT_low_pc */
+	.uleb128	0x1			/* DW_FORM_addr */
+	.uleb128	0x12			/* DW_AT_high_pc */
+	.uleb128	0x1			/* DW_FORM_addr */
+	.uleb128	0x40			/* DW_AT_frame_base */
+	.uleb128	0xa			/* DW_FORM_block1 */
+	.byte		0x0			/* Terminator */
+	.byte		0x0			/* Terminator */
+
+	.uleb128	3			/* 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	4			/* Abbrev code */
+	.uleb128	0x2e			/* DW_TAG_subprogram */
+	.byte		0			/* has_children */
+	.uleb128	0x3f			/* DW_AT_external */
+	.uleb128	0xc			/* DW_FORM_flag */
+	.uleb128	0x3a			/* DW_AT_decl_file */
+	.uleb128	0xb			/* DW_FORM_data1 */
+	.uleb128	0x3b			/* DW_AT_decl_line */
+	.uleb128	0xb			/* DW_FORM_data1 */
+	.uleb128	0x49			/* DW_AT_type */
+	.uleb128	0x13			/* DW_FORM_ref4 */
+	.uleb128	0x11			/* DW_AT_low_pc */
+	.uleb128	0x1			/* DW_FORM_addr */
+	.uleb128	0x12			/* DW_AT_high_pc */
+	.uleb128	0x1			/* DW_FORM_addr */
+	.uleb128	0x40			/* DW_AT_frame_base */
+	.uleb128	0xa			/* DW_FORM_block1 */
+	.byte		0x0			/* Terminator */
+	.byte		0x0			/* Terminator */
+
+	.byte		0x0			/* Terminator */
+	.byte		0x0			/* Terminator */
+
+/* Line table */
+	.section .debug_line
+.Lline1_begin:
+	.4byte		.Lline1_end - .Lline1_start	/* Initial length */
+.Lline1_start:
+	.2byte		2			/* Version */
+	.4byte		.Lline1_lines - .Lline1_hdr	/* header_length */
+.Lline1_hdr:
+	.byte		1			/* Minimum insn length */
+	.byte		1			/* default_is_stmt */
+	.byte		1			/* line_base */
+	.byte		1			/* line_range */
+	.byte		0x10			/* opcode_base */
+
+	/* Standard lengths */
+	.byte		0
+	.byte		1
+	.byte		1
+	.byte		1
+	.byte		1
+	.byte		0
+	.byte		0
+	.byte		0
+	.byte		1
+	.byte		0
+	.byte		0
+	.byte		1
+	.byte		0
+	.byte		0
+	.byte		0
+
+	/* Include directories */
+	.byte		0
+
+	/* File names */
+	.ascii		"file1.txt\0"
+	.uleb128	0
+	.uleb128	0
+	.uleb128	0
+
+	.byte		0
+
+.Lline1_lines:
+	.byte		0	/* DW_LNE_set_address */
+	.uleb128	5
+	.byte		2
+	.4byte		.Lbegin_func_cu1
+
+	.byte		3	/* DW_LNS_advance_line */
+	.sleb128	3	/* ... to 4 */
+
+	.byte		1	/* DW_LNS_copy */
+
+	.byte		1	/* DW_LNS_copy (second time as an end-of-prologue marker) */
+
+	.byte		0	/* DW_LNE_set_address */
+	.uleb128	5
+	.byte		2
+	.4byte		.Lend_func_cu1
+
+	.byte		0	/* DW_LNE_end_of_sequence */
+	.uleb128	1
+	.byte		1
+
+.Lline1_end:
diff --git a/gdb/testsuite/gdb.dwarf2/dw2-anonymous-func.exp b/gdb/testsuite/gdb.dwarf2/dw2-anonymous-func.exp
new file mode 100644
index 0000000..10662eb
--- /dev/null
+++ b/gdb/testsuite/gdb.dwarf2/dw2-anonymous-func.exp
@@ -0,0 +1,53 @@
+# Copyright 2004, 2005, 2007, 2008, 2009, 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 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/>.
+
+# Minimal DWARF-2 unit test
+
+# 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-anonymous-func"
+set dwarf_srcfile "file1.txt"
+set srcfile ${testfile}.S
+set binfile ${objdir}/${subdir}/${testfile}.x
+
+if  { [gdb_compile "${srcdir}/${subdir}/main.c" "main.o" object {debug}] != "" } {
+    return -1
+}
+
+if  { [gdb_compile "${srcdir}/${subdir}/${srcfile}" "${testfile}.o" object {nodebug}] != "" } {
+    return -1
+}
+
+if  { [gdb_compile "${testfile}.o main.o" "${binfile}" executable {debug}] != "" } {
+    return -1
+}
+
+gdb_exit
+gdb_start
+gdb_reinitialize_dir $srcdir/$subdir
+gdb_load ${binfile}
+
+# Force the debugger to create the file1.txt symtab, to make sure that
+# the debugger does not crash doing so.
+gdb_test "list file1.txt:1" "File 1 Line 1.*File 1 Line 8" "list file1.txt"
-- 
1.6.3.3

Re: [RFA/dwarf] Anonymous nested function causes SEGV during psymbol read

[Tom Tromey]

>>>>> "Joel" == Joel Brobecker <brobecker@adacore.com> writes:

Joel> +	  /* Ignore subprograms that do not have a name.  Such entries
Joel> +	     are incorrect, according to the DWARF standard, and we need
Joel> +	     a function name to create the associated partial symbol.  */
Joel> +	  if (!pdi->is_declaration && pdi->name)
Joel>              add_partial_symbol (pdi, cu);

I think it is worthwhile to call complaint for invalid DWARF.

Tom

Re: [RFA/dwarf] Anonymous nested function causes SEGV during psymbol read

[Joel Brobecker]

> Joel> +	  /* Ignore subprograms that do not have a name.  Such entries
> Joel> +	     are incorrect, according to the DWARF standard, and we need
> Joel> +	     a function name to create the associated partial symbol.  */
> Joel> +	  if (!pdi->is_declaration && pdi->name)
> Joel>              add_partial_symbol (pdi, cu);
> 
> I think it is worthwhile to call complaint for invalid DWARF.

Not a problem - I will take care of that (I think we should complain in
all cases, so that'll be two sites that need to be complaning). I'm answering
now without a new patch because I won't have time to look into thin until
early march, but I will.

-- 
Joel

Re: [RFA/dwarf] Anonymous nested function causes SEGV during psymbol read

[Joel Brobecker]

[-- Attachment #1: Type: text/plain, Size: 738 bytes --]

> Joel> +	  /* Ignore subprograms that do not have a name.  Such entries
> Joel> +	     are incorrect, according to the DWARF standard, and we need
> Joel> +	     a function name to create the associated partial symbol.  */
> Joel> +	  if (!pdi->is_declaration && pdi->name)
> Joel>              add_partial_symbol (pdi, cu);
> 
> I think it is worthwhile to call complaint for invalid DWARF.

Thanks again for the feedback.  Attached is a new version of the patch,
with the complaints added.  Since I also added a complaint for the
non-nested case, I also extended the testcase to cover that case as
well.

I will leave the patch out for review for a while, and hopefully commit
sometime next week, if there are no objections.

-- 
Joel

[-- Attachment #2: dw2-anon-func.diff --]
[-- Type: text/x-diff, Size: 12953 bytes --]

commit 22ada2cfef694620508dffa0e05a19e6b8d3da8c
Author: Joel Brobecker <brobecker@adacore.com>
Date:   Wed Feb 17 07:29:04 2010 +0400

    [dwarf] Anonymous nested function causes SEGV during psymbol read
    
    According to the DWARF3 standard, a function always has a name attribute
    (Section 3.3 - Subroutine and Entry Point Entries).  The only exception
    is when a DW_AT_abstract_origin attribute is provided, in which case
    the name may be inherited from the referenced DIE.
    
    The problem occured because our compiler generated a subprogram DIE
    for a nested function where the name attribute was missing (and no
    abstract-origin either).  Our code in add_partial_symbol is not
    prepared to deal with the situation, and happily just tries  to compute
    the length of the (NULL) function name.
    
    This normally cannot happen, because there is already a guard in
    scan_partial_symbols, where we (silently!) ignore anonymous dies,
    including anonymous subprograms. Unfortunately, there is a flaw that
    affects Ada and other languages that allow nested subprograms. For
    nested subprograms, we do not go through scan_partial_symbols and
    thus we are missing the name check.
    
    This patch adds the name check in the nested subprogram case, and
    emits a complaint if missing.  To be consistent, a complaint has also
    been added to cover the non-nested case.
    
    gdb/ChangeLog:
    
            * dwarf2read.c (scan_partial_symbols): Emit a complaint if
            PDI is a subprogram without a name attribute.
            (add_partial_subprogram): If the subprogram does not
            have a name, do not create the associated partial symbol but
            emit a complaint.
    
    gdb/testsuite/ChangeLog:
    
            * gdb.dwarf2/dw2-anonymous-func.S: New file.
            * gdb.dwarf2/dw2-anonymous-func.exp: New testcase.
    
    Tested on x86_64-linux, no regression.  Note that the testcase also
    verifies that the psymtab->symtab conversion does not crash (this is
    the purpose of the "list file1.txt:1" test.

diff --git a/gdb/dwarf2read.c b/gdb/dwarf2read.c
index 563cb18..b6e51ef 100644
--- a/gdb/dwarf2read.c
+++ b/gdb/dwarf2read.c
@@ -2241,6 +2241,12 @@ scan_partial_symbols (struct partial_die_info *first_die, CORE_ADDR *lowpc,
 	      break;
 	    }
 	}
+      else if (pdi->tag == DW_TAG_subprogram)
+	/* This is a subprogram DIE that does not have a name, which is
+	   invalid.  */
+	complaint (&symfile_complaints,
+		   _("missing name for DW_TAG_subprogram DIE at 321 %d"),
+		   pdi->offset);
 
       /* If the die has a sibling, skip to the sibling.  */
 
@@ -2572,8 +2578,17 @@ add_partial_subprogram (struct partial_die_info *pdi,
 				 pdi->highpc - 1 + baseaddr,
 				 cu->per_cu->psymtab);
 	    }
-          if (!pdi->is_declaration)
-            add_partial_symbol (pdi, cu);
+	  if (!pdi->is_declaration)
+	    {
+	      if (pdi->name)
+		add_partial_symbol (pdi, cu);
+	      else
+		/* This subprogram die is missing its name attribute, which
+		   is illegal accordingly to the DWARF standard.  */
+	      complaint (&symfile_complaints,
+			 _("missing name for DW_TAG_subprogram DIE at %d"),
+			 pdi->offset);
+	    }
         }
     }
   
diff --git a/gdb/testsuite/gdb.dwarf2/dw2-anonymous-func.S b/gdb/testsuite/gdb.dwarf2/dw2-anonymous-func.S
new file mode 100644
index 0000000..84552bf
--- /dev/null
+++ b/gdb/testsuite/gdb.dwarf2/dw2-anonymous-func.S
@@ -0,0 +1,248 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2004, 2007, 2008, 2009, 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 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 a minimal file containing DWARF-2 information.  This test also
+   serves as a skeleton for other DWARF-2 tests.  Most other tests will
+   not be this extensively itemized and commented...  */
+
+/* Dummy function to provide debug information for.  */
+
+	.text
+.Lbegin_text1:
+	.globl func_cu1
+	.type func_cu1, %function
+func_cu1:
+.Lbegin_func_cu1:
+	.int 0
+.Lend_func_cu1:
+	.size func_cu1, .-func_cu1
+	.globl func_cu2
+	.type func_cu2, %function
+func_cu2:
+.Lbegin_func_cu2:
+	.int 0
+.Lend_func_cu2:
+	.size func_cu2, .-func_cu2
+.Lend_text1:
+
+/* Debug information */
+
+	.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 */
+	.4byte	.Lline1_begin			/* DW_AT_stmt_list */
+	.4byte	.Lend_text1			/* DW_AT_high_pc */
+	.4byte	.Lbegin_text1			/* DW_AT_low_pc */
+	.ascii	"file1.txt\0"			/* DW_AT_name */
+	.ascii	"GNU C 3.3.3\0"			/* DW_AT_producer */
+	.byte	0x0d				/* DW_AT_language (Ada95) */
+
+	/* func_cu1 */
+	.uleb128	2			/* Abbrev: DW_TAG_subprogram */
+	.byte		1			/* DW_AT_external */
+	.byte		1			/* DW_AT_decl_file */
+	.byte		2			/* DW_AT_decl_line */
+	.ascii		"func_cu1\0"		/* DW_AT_name */
+	.4byte		.Ltype_int-.Lcu1_begin	/* DW_AT_type */
+	.4byte		.Lbegin_func_cu1	/* DW_AT_low_pc */
+	.4byte		.Lend_func_cu1		/* DW_AT_high_pc */
+	.byte		1			/* DW_AT_frame_base: length */
+	.byte		0x55			/* DW_AT_frame_base: DW_OP_reg5 */
+	/* Nested function missing a name attribute.  */
+	.uleb128	4			/* Abbrev: DW_TAG_subprogram */
+	.byte		1			/* DW_AT_external */
+	.byte		1			/* DW_AT_decl_file */
+	.byte		2			/* DW_AT_decl_line */
+	.4byte		.Ltype_int-.Lcu1_begin	/* DW_AT_type */
+	.4byte		.Lbegin_func_cu2	/* DW_AT_low_pc */
+	.4byte		.Lend_func_cu2		/* DW_AT_high_pc */
+	.byte		1			/* DW_AT_frame_base: length */
+	.byte		0x55			/* DW_AT_frame_base: DW_OP_reg5 */
+	.byte		0x0			/* End of children of func_cu1 */
+
+	/* Non-nested function missing a name attribute.  */
+	.uleb128	4			/* Abbrev: DW_TAG_subprogram */
+	.byte		1			/* DW_AT_external */
+	.byte		1			/* DW_AT_decl_file */
+	.byte		2			/* DW_AT_decl_line */
+	.4byte		.Ltype_int-.Lcu1_begin	/* DW_AT_type */
+	.4byte		.Lbegin_func_cu2	/* DW_AT_low_pc */
+	.4byte		.Lend_func_cu2		/* DW_AT_high_pc */
+	.byte		1			/* DW_AT_frame_base: length */
+	.byte		0x55			/* DW_AT_frame_base: DW_OP_reg5 */
+
+.Ltype_int:
+	.uleb128	3			/* Abbrev: DW_TAG_base_type */
+	.ascii		"int\0"			/* DW_AT_name */
+	.byte		4			/* DW_AT_byte_size */
+	.byte		5			/* DW_AT_encoding */
+
+	.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	0x10			/* DW_AT_stmt_list */
+	.uleb128	0x6			/* DW_FORM_data4 */
+	.uleb128	0x12			/* DW_AT_high_pc */
+	.uleb128	0x1			/* DW_FORM_addr */
+	.uleb128	0x11			/* DW_AT_low_pc */
+	.uleb128	0x1			/* DW_FORM_addr */
+	.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	0x2e			/* DW_TAG_subprogram */
+	.byte		1			/* has_children */
+	.uleb128	0x3f			/* DW_AT_external */
+	.uleb128	0xc			/* DW_FORM_flag */
+	.uleb128	0x3a			/* DW_AT_decl_file */
+	.uleb128	0xb			/* DW_FORM_data1 */
+	.uleb128	0x3b			/* DW_AT_decl_line */
+	.uleb128	0xb			/* DW_FORM_data1 */
+	.uleb128	0x3			/* DW_AT_name */
+	.uleb128	0x8			/* DW_FORM_string */
+	.uleb128	0x49			/* DW_AT_type */
+	.uleb128	0x13			/* DW_FORM_ref4 */
+	.uleb128	0x11			/* DW_AT_low_pc */
+	.uleb128	0x1			/* DW_FORM_addr */
+	.uleb128	0x12			/* DW_AT_high_pc */
+	.uleb128	0x1			/* DW_FORM_addr */
+	.uleb128	0x40			/* DW_AT_frame_base */
+	.uleb128	0xa			/* DW_FORM_block1 */
+	.byte		0x0			/* Terminator */
+	.byte		0x0			/* Terminator */
+
+	.uleb128	3			/* 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	4			/* Abbrev code */
+	.uleb128	0x2e			/* DW_TAG_subprogram */
+	.byte		0			/* has_children */
+	.uleb128	0x3f			/* DW_AT_external */
+	.uleb128	0xc			/* DW_FORM_flag */
+	.uleb128	0x3a			/* DW_AT_decl_file */
+	.uleb128	0xb			/* DW_FORM_data1 */
+	.uleb128	0x3b			/* DW_AT_decl_line */
+	.uleb128	0xb			/* DW_FORM_data1 */
+	.uleb128	0x49			/* DW_AT_type */
+	.uleb128	0x13			/* DW_FORM_ref4 */
+	.uleb128	0x11			/* DW_AT_low_pc */
+	.uleb128	0x1			/* DW_FORM_addr */
+	.uleb128	0x12			/* DW_AT_high_pc */
+	.uleb128	0x1			/* DW_FORM_addr */
+	.uleb128	0x40			/* DW_AT_frame_base */
+	.uleb128	0xa			/* DW_FORM_block1 */
+	.byte		0x0			/* Terminator */
+	.byte		0x0			/* Terminator */
+
+	.byte		0x0			/* Terminator */
+	.byte		0x0			/* Terminator */
+
+/* Line table */
+	.section .debug_line
+.Lline1_begin:
+	.4byte		.Lline1_end - .Lline1_start	/* Initial length */
+.Lline1_start:
+	.2byte		2			/* Version */
+	.4byte		.Lline1_lines - .Lline1_hdr	/* header_length */
+.Lline1_hdr:
+	.byte		1			/* Minimum insn length */
+	.byte		1			/* default_is_stmt */
+	.byte		1			/* line_base */
+	.byte		1			/* line_range */
+	.byte		0x10			/* opcode_base */
+
+	/* Standard lengths */
+	.byte		0
+	.byte		1
+	.byte		1
+	.byte		1
+	.byte		1
+	.byte		0
+	.byte		0
+	.byte		0
+	.byte		1
+	.byte		0
+	.byte		0
+	.byte		1
+	.byte		0
+	.byte		0
+	.byte		0
+
+	/* Include directories */
+	.byte		0
+
+	/* File names */
+	.ascii		"file1.txt\0"
+	.uleb128	0
+	.uleb128	0
+	.uleb128	0
+
+	.byte		0
+
+.Lline1_lines:
+	.byte		0	/* DW_LNE_set_address */
+	.uleb128	5
+	.byte		2
+	.4byte		.Lbegin_func_cu1
+
+	.byte		3	/* DW_LNS_advance_line */
+	.sleb128	3	/* ... to 4 */
+
+	.byte		1	/* DW_LNS_copy */
+
+	.byte		1	/* DW_LNS_copy (second time as an end-of-prologue marker) */
+
+	.byte		0	/* DW_LNE_set_address */
+	.uleb128	5
+	.byte		2
+	.4byte		.Lend_func_cu1
+
+	.byte		0	/* DW_LNE_end_of_sequence */
+	.uleb128	1
+	.byte		1
+
+.Lline1_end:
diff --git a/gdb/testsuite/gdb.dwarf2/dw2-anonymous-func.exp b/gdb/testsuite/gdb.dwarf2/dw2-anonymous-func.exp
new file mode 100644
index 0000000..10662eb
--- /dev/null
+++ b/gdb/testsuite/gdb.dwarf2/dw2-anonymous-func.exp
@@ -0,0 +1,53 @@
+# Copyright 2004, 2005, 2007, 2008, 2009, 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 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/>.
+
+# Minimal DWARF-2 unit test
+
+# 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-anonymous-func"
+set dwarf_srcfile "file1.txt"
+set srcfile ${testfile}.S
+set binfile ${objdir}/${subdir}/${testfile}.x
+
+if  { [gdb_compile "${srcdir}/${subdir}/main.c" "main.o" object {debug}] != "" } {
+    return -1
+}
+
+if  { [gdb_compile "${srcdir}/${subdir}/${srcfile}" "${testfile}.o" object {nodebug}] != "" } {
+    return -1
+}
+
+if  { [gdb_compile "${testfile}.o main.o" "${binfile}" executable {debug}] != "" } {
+    return -1
+}
+
+gdb_exit
+gdb_start
+gdb_reinitialize_dir $srcdir/$subdir
+gdb_load ${binfile}
+
+# Force the debugger to create the file1.txt symtab, to make sure that
+# the debugger does not crash doing so.
+gdb_test "list file1.txt:1" "File 1 Line 1.*File 1 Line 8" "list file1.txt"

Re: [RFA/dwarf] Anonymous nested function causes SEGV during psymbol read

[Joel Brobecker]

[-- Attachment #1: Type: text/plain, Size: 805 bytes --]

> Thanks again for the feedback.  Attached is a new version of the patch,
> with the complaints added.  Since I also added a complaint for the
> non-nested case, I also extended the testcase to cover that case as
> well.

Yet another version: Instead of generating the complaint while creating
the psymbols, I decided to generate them during the symtab creation
phase. A couple of reasons:
  - From an implementation perspective, it means that I only have to
    generate the complete from one location in our code.
  - Instead of generating a complaint for all broken DIEs all at once
    at startup, just generate them when it affects a unit which the user
    is actually referring to.
  - If we ever get rid of the psymtab, we'd lose the warning...

That's why I like this version better...

-- 
Joel

[-- Attachment #2: dw2-anon-subprogram.diff --]
[-- Type: text/x-diff, Size: 13364 bytes --]

commit 82a94c19a204c46c5666e72a9071bf99d481a275
Author: Joel Brobecker <brobecker@adacore.com>
Date:   Wed Feb 17 07:29:04 2010 +0400

    [dwarf] Anonymous nested function causes SEGV during psymbol read
    
    According to the DWARF3 standard, a function always has a name attribute
    (Section 3.3 - Subroutine and Entry Point Entries).  The only exception
    is when a DW_AT_abstract_origin attribute is provided, in which case
    the name may be inherited from the referenced DIE.
    
    The problem occured because our compiler generated a subprogram DIE
    for a nested function where the name attribute was missing (and no
    abstract-origin either).  Our code in add_partial_symbol is not
    prepared to deal with the situation, and happily just tries  to compute
    the length of the (NULL) function name.
    
    This normally cannot happen, because there is already a guard in
    scan_partial_symbols, where we (silently!) ignore anonymous dies,
    including anonymous subprograms. Unfortunately, there is a flaw that
    affects Ada and other languages that allow nested subprograms. For
    nested subprograms, we do not go through scan_partial_symbols and
    thus we are missing the name check.
    
    This patch adds the name check in the nested subprogram case. It also
    adds a complaint which is emitted during the psymtab->symtab conversion
    phase.
    
    gdb/ChangeLog:
    
            * dwarf2read.c (add_partial_subprogram): Make sure the subprogram
            DIE has a name before creating the associated partial symbol.
            (read_func_scope): Emit a complaint if the subprogram does not
            have a name or when we can't extract the subprogram PC bounds.
    
    gdb/testsuite/ChangeLog:
    
            * gdb.dwarf2/dw2-anonymous-func.S: New file.
            * gdb.dwarf2/dw2-anonymous-func.exp: New testcase.
    
    Tested on x86_64-linux, no regression.  Note that the testcase also
    verifies that the psymtab->symtab conversion does not crash (this is
    the purpose of the "list file1.txt:1" test.

diff --git a/gdb/dwarf2read.c b/gdb/dwarf2read.c
index 563cb18..02b10d9 100644
--- a/gdb/dwarf2read.c
+++ b/gdb/dwarf2read.c
@@ -2573,7 +2573,11 @@ add_partial_subprogram (struct partial_die_info *pdi,
 				 cu->per_cu->psymtab);
 	    }
           if (!pdi->is_declaration)
-            add_partial_symbol (pdi, cu);
+	    /* Ignore subprogram DIEs that do not have a name, they are
+	       illegal.  Do not emit a complaint at this point, we will
+	       do so when we convert this psymtab into a symtab.  */
+	    if (pdi->name)
+	      add_partial_symbol (pdi, cu);
         }
     }
   
@@ -3857,10 +3861,23 @@ read_func_scope (struct die_info *die, struct dwarf2_cu *cu)
 
   name = dwarf2_name (die, cu);
 
-  /* Ignore functions with missing or empty names and functions with
-     missing or invalid low and high pc attributes.  */
-  if (name == NULL || !dwarf2_get_pc_bounds (die, &lowpc, &highpc, cu, NULL))
-    return;
+  /* Ignore functions with missing or empty names.  These are actually
+     illegal according to the DWARF standard.  */
+  if (name == NULL)
+    {
+      complaint (&symfile_complaints,
+                 _("missing name for subprogram DIE at %d"), die->offset);
+      return;
+    }
+
+  /* Ignore functions with missing or invalid low and high pc attributes.  */
+  if (!dwarf2_get_pc_bounds (die, &lowpc, &highpc, cu, NULL))
+    {
+      complaint (&symfile_complaints,
+                 _("cannot get low and high bounds for subprogram DIE at %d"),
+                 die->offset);
+      return;
+    }
 
   lowpc += baseaddr;
   highpc += baseaddr;
diff --git a/gdb/testsuite/gdb.dwarf2/dw2-anonymous-func.S b/gdb/testsuite/gdb.dwarf2/dw2-anonymous-func.S
new file mode 100644
index 0000000..84552bf
--- /dev/null
+++ b/gdb/testsuite/gdb.dwarf2/dw2-anonymous-func.S
@@ -0,0 +1,248 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2004, 2007, 2008, 2009, 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 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 a minimal file containing DWARF-2 information.  This test also
+   serves as a skeleton for other DWARF-2 tests.  Most other tests will
+   not be this extensively itemized and commented...  */
+
+/* Dummy function to provide debug information for.  */
+
+	.text
+.Lbegin_text1:
+	.globl func_cu1
+	.type func_cu1, %function
+func_cu1:
+.Lbegin_func_cu1:
+	.int 0
+.Lend_func_cu1:
+	.size func_cu1, .-func_cu1
+	.globl func_cu2
+	.type func_cu2, %function
+func_cu2:
+.Lbegin_func_cu2:
+	.int 0
+.Lend_func_cu2:
+	.size func_cu2, .-func_cu2
+.Lend_text1:
+
+/* Debug information */
+
+	.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 */
+	.4byte	.Lline1_begin			/* DW_AT_stmt_list */
+	.4byte	.Lend_text1			/* DW_AT_high_pc */
+	.4byte	.Lbegin_text1			/* DW_AT_low_pc */
+	.ascii	"file1.txt\0"			/* DW_AT_name */
+	.ascii	"GNU C 3.3.3\0"			/* DW_AT_producer */
+	.byte	0x0d				/* DW_AT_language (Ada95) */
+
+	/* func_cu1 */
+	.uleb128	2			/* Abbrev: DW_TAG_subprogram */
+	.byte		1			/* DW_AT_external */
+	.byte		1			/* DW_AT_decl_file */
+	.byte		2			/* DW_AT_decl_line */
+	.ascii		"func_cu1\0"		/* DW_AT_name */
+	.4byte		.Ltype_int-.Lcu1_begin	/* DW_AT_type */
+	.4byte		.Lbegin_func_cu1	/* DW_AT_low_pc */
+	.4byte		.Lend_func_cu1		/* DW_AT_high_pc */
+	.byte		1			/* DW_AT_frame_base: length */
+	.byte		0x55			/* DW_AT_frame_base: DW_OP_reg5 */
+	/* Nested function missing a name attribute.  */
+	.uleb128	4			/* Abbrev: DW_TAG_subprogram */
+	.byte		1			/* DW_AT_external */
+	.byte		1			/* DW_AT_decl_file */
+	.byte		2			/* DW_AT_decl_line */
+	.4byte		.Ltype_int-.Lcu1_begin	/* DW_AT_type */
+	.4byte		.Lbegin_func_cu2	/* DW_AT_low_pc */
+	.4byte		.Lend_func_cu2		/* DW_AT_high_pc */
+	.byte		1			/* DW_AT_frame_base: length */
+	.byte		0x55			/* DW_AT_frame_base: DW_OP_reg5 */
+	.byte		0x0			/* End of children of func_cu1 */
+
+	/* Non-nested function missing a name attribute.  */
+	.uleb128	4			/* Abbrev: DW_TAG_subprogram */
+	.byte		1			/* DW_AT_external */
+	.byte		1			/* DW_AT_decl_file */
+	.byte		2			/* DW_AT_decl_line */
+	.4byte		.Ltype_int-.Lcu1_begin	/* DW_AT_type */
+	.4byte		.Lbegin_func_cu2	/* DW_AT_low_pc */
+	.4byte		.Lend_func_cu2		/* DW_AT_high_pc */
+	.byte		1			/* DW_AT_frame_base: length */
+	.byte		0x55			/* DW_AT_frame_base: DW_OP_reg5 */
+
+.Ltype_int:
+	.uleb128	3			/* Abbrev: DW_TAG_base_type */
+	.ascii		"int\0"			/* DW_AT_name */
+	.byte		4			/* DW_AT_byte_size */
+	.byte		5			/* DW_AT_encoding */
+
+	.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	0x10			/* DW_AT_stmt_list */
+	.uleb128	0x6			/* DW_FORM_data4 */
+	.uleb128	0x12			/* DW_AT_high_pc */
+	.uleb128	0x1			/* DW_FORM_addr */
+	.uleb128	0x11			/* DW_AT_low_pc */
+	.uleb128	0x1			/* DW_FORM_addr */
+	.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	0x2e			/* DW_TAG_subprogram */
+	.byte		1			/* has_children */
+	.uleb128	0x3f			/* DW_AT_external */
+	.uleb128	0xc			/* DW_FORM_flag */
+	.uleb128	0x3a			/* DW_AT_decl_file */
+	.uleb128	0xb			/* DW_FORM_data1 */
+	.uleb128	0x3b			/* DW_AT_decl_line */
+	.uleb128	0xb			/* DW_FORM_data1 */
+	.uleb128	0x3			/* DW_AT_name */
+	.uleb128	0x8			/* DW_FORM_string */
+	.uleb128	0x49			/* DW_AT_type */
+	.uleb128	0x13			/* DW_FORM_ref4 */
+	.uleb128	0x11			/* DW_AT_low_pc */
+	.uleb128	0x1			/* DW_FORM_addr */
+	.uleb128	0x12			/* DW_AT_high_pc */
+	.uleb128	0x1			/* DW_FORM_addr */
+	.uleb128	0x40			/* DW_AT_frame_base */
+	.uleb128	0xa			/* DW_FORM_block1 */
+	.byte		0x0			/* Terminator */
+	.byte		0x0			/* Terminator */
+
+	.uleb128	3			/* 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	4			/* Abbrev code */
+	.uleb128	0x2e			/* DW_TAG_subprogram */
+	.byte		0			/* has_children */
+	.uleb128	0x3f			/* DW_AT_external */
+	.uleb128	0xc			/* DW_FORM_flag */
+	.uleb128	0x3a			/* DW_AT_decl_file */
+	.uleb128	0xb			/* DW_FORM_data1 */
+	.uleb128	0x3b			/* DW_AT_decl_line */
+	.uleb128	0xb			/* DW_FORM_data1 */
+	.uleb128	0x49			/* DW_AT_type */
+	.uleb128	0x13			/* DW_FORM_ref4 */
+	.uleb128	0x11			/* DW_AT_low_pc */
+	.uleb128	0x1			/* DW_FORM_addr */
+	.uleb128	0x12			/* DW_AT_high_pc */
+	.uleb128	0x1			/* DW_FORM_addr */
+	.uleb128	0x40			/* DW_AT_frame_base */
+	.uleb128	0xa			/* DW_FORM_block1 */
+	.byte		0x0			/* Terminator */
+	.byte		0x0			/* Terminator */
+
+	.byte		0x0			/* Terminator */
+	.byte		0x0			/* Terminator */
+
+/* Line table */
+	.section .debug_line
+.Lline1_begin:
+	.4byte		.Lline1_end - .Lline1_start	/* Initial length */
+.Lline1_start:
+	.2byte		2			/* Version */
+	.4byte		.Lline1_lines - .Lline1_hdr	/* header_length */
+.Lline1_hdr:
+	.byte		1			/* Minimum insn length */
+	.byte		1			/* default_is_stmt */
+	.byte		1			/* line_base */
+	.byte		1			/* line_range */
+	.byte		0x10			/* opcode_base */
+
+	/* Standard lengths */
+	.byte		0
+	.byte		1
+	.byte		1
+	.byte		1
+	.byte		1
+	.byte		0
+	.byte		0
+	.byte		0
+	.byte		1
+	.byte		0
+	.byte		0
+	.byte		1
+	.byte		0
+	.byte		0
+	.byte		0
+
+	/* Include directories */
+	.byte		0
+
+	/* File names */
+	.ascii		"file1.txt\0"
+	.uleb128	0
+	.uleb128	0
+	.uleb128	0
+
+	.byte		0
+
+.Lline1_lines:
+	.byte		0	/* DW_LNE_set_address */
+	.uleb128	5
+	.byte		2
+	.4byte		.Lbegin_func_cu1
+
+	.byte		3	/* DW_LNS_advance_line */
+	.sleb128	3	/* ... to 4 */
+
+	.byte		1	/* DW_LNS_copy */
+
+	.byte		1	/* DW_LNS_copy (second time as an end-of-prologue marker) */
+
+	.byte		0	/* DW_LNE_set_address */
+	.uleb128	5
+	.byte		2
+	.4byte		.Lend_func_cu1
+
+	.byte		0	/* DW_LNE_end_of_sequence */
+	.uleb128	1
+	.byte		1
+
+.Lline1_end:
diff --git a/gdb/testsuite/gdb.dwarf2/dw2-anonymous-func.exp b/gdb/testsuite/gdb.dwarf2/dw2-anonymous-func.exp
new file mode 100644
index 0000000..10662eb
--- /dev/null
+++ b/gdb/testsuite/gdb.dwarf2/dw2-anonymous-func.exp
@@ -0,0 +1,53 @@
+# Copyright 2004, 2005, 2007, 2008, 2009, 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 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/>.
+
+# Minimal DWARF-2 unit test
+
+# 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-anonymous-func"
+set dwarf_srcfile "file1.txt"
+set srcfile ${testfile}.S
+set binfile ${objdir}/${subdir}/${testfile}.x
+
+if  { [gdb_compile "${srcdir}/${subdir}/main.c" "main.o" object {debug}] != "" } {
+    return -1
+}
+
+if  { [gdb_compile "${srcdir}/${subdir}/${srcfile}" "${testfile}.o" object {nodebug}] != "" } {
+    return -1
+}
+
+if  { [gdb_compile "${testfile}.o main.o" "${binfile}" executable {debug}] != "" } {
+    return -1
+}
+
+gdb_exit
+gdb_start
+gdb_reinitialize_dir $srcdir/$subdir
+gdb_load ${binfile}
+
+# Force the debugger to create the file1.txt symtab, to make sure that
+# the debugger does not crash doing so.
+gdb_test "list file1.txt:1" "File 1 Line 1.*File 1 Line 8" "list file1.txt"

Re: [RFA/dwarf] Anonymous nested function causes SEGV during psymbol read

[Tom Tromey]

>>>>> "Joel" == Joel Brobecker <brobecker@adacore.com> writes:

Joel> Yet another version: Instead of generating the complaint while creating
Joel> the psymbols, I decided to generate them during the symtab creation
Joel> phase. A couple of reasons:
[...]
Joel> That's why I like this version better...

FWIW, seems reasonable to me.

Tom

Re: [RFA/dwarf] Anonymous nested function causes SEGV during psymbol read

[Joel Brobecker]

> Joel> Yet another version: Instead of generating the complaint while creating
> Joel> the psymbols, I decided to generate them during the symtab creation
> Joel> phase. A couple of reasons:
> [...]
> Joel> That's why I like this version better...
> 
> FWIW, seems reasonable to me.

Thanks! Checked in (I just lOoove that git cvsexportcommit thing :).

The only thing is the length of the commit messages. They now contain
the full description of the issue this patch is fixing, very close to
the initial email I send when submitting a patch.  Is that a problem
with anyone?
-- 
Joel

Re: [RFA/dwarf] Anonymous nested function causes SEGV during psymbol read

[Tom Tromey]

>>>>> "Joel" == Joel Brobecker <brobecker@adacore.com> writes:

Joel> The only thing is the length of the commit messages. They now contain
Joel> the full description of the issue this patch is fixing, very close to
Joel> the initial email I send when submitting a patch.  Is that a problem
Joel> with anyone?

I personally don't care.  Though, FWIW, I don't use the auto-commit
feature of git cvsexportcommit.  I just do it the old way, including
mashing up all the different ChangeLog entries manually.

Tom