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[dwarf] Anonymous nested function causes SEGV during psymbol read

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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.
This commit is contained in:
Joel Brobecker
2010-03-18 18:35:55 +00:00
parent 2cff808dfa
commit e8d054800a
5 changed files with 335 additions and 5 deletions
Download Patch File Download Diff File Expand all files Collapse all files

7
gdb/ChangeLog
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@@ -3,6 +3,13 @@
* infcmd.c (finish_command_continuation): Wrap print_return_value
in TRY_CATCH.
2010-03-18 Joel Brobecker <brobecker@adacore.com>
* 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.
2010-03-18 Ulrich Weigand <uweigand@de.ibm.com>
* mi/mi-main.c (mi_cmd_list_thread_groups): Use get_current_arch

27
gdb/dwarf2read.c
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@@ -2583,7 +2583,11 @@ 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);
}
}
@@ -3867,10 +3871,23 @@ 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;

5
gdb/testsuite/ChangeLog
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@@ -1,3 +1,8 @@
2010-03-18 Joel Brobecker <brobecker@adacore.com>
* gdb.dwarf2/dw2-anonymous-func.S: New file.
* gdb.dwarf2/dw2-anonymous-func.exp: New testcase.
2010-03-18 Ulrich Weigand <Ulrich.Weigand@de.ibm.com>
* gdb.mi/gdb680.exp: Revert 2009-06-17 change.

248
gdb/testsuite/gdb.dwarf2/dw2-anonymous-func.S Normal file
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@@ -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:

53
gdb/testsuite/gdb.dwarf2/dw2-anonymous-func.exp Normal file
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@@ -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"