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[patch] Fix dwarf2read to crash again
- From: Jan Kratochvil <jan dot kratochvil at redhat dot com>
- To: gdb-patches at sourceware dot org
- Date: Wed, 21 Apr 2010 11:13:03 +0200
- Subject: [patch] Fix dwarf2read to crash again
Hi,
there are multiple related patches:
[modula2]
Re: recursive bug in dwarf2read.c
From: Gaius Mulley <gaius at glam dot ac dot uk>
http://sourceware.org/ml/gdb-patches/2009-12/msg00152.html
http://sourceware.org/ml/gdb-cvs/2009-12/msg00068.html
2d04d865270162e7119b668cc4b2865fb75d5cd1
Attached here a new testcase for it:
gdb.dwarf2/dw2-modula2-self-type.exp
[physname]
Re: [RFA] dwarf2_physname FINAL
http://sourceware.org/ml/gdb-patches/2010-03/msg00359.html
42284fdf9d8cdb20c8e833bdbdb2b56977fea525
[readerror]
[patch] Fix crash on NULL function's TYPE_FIELD_TYPE
http://sourceware.org/ml/gdb-patches/2010-03/msg01039.html
http://sourceware.org/ml/gdb-cvs/2010-03/msg00302.html
7e8e956c34e0fd4f0b59ef1c46f8966c66fffbf3
The checked-in testcase is:
gdb.dwarf2/dw2-bad-parameter-type.exp
[delay]
[RFA] Delayed physname computation
http://sourceware.org/ml/gdb-patches/2010-04/msg00641.html
Posted now, the new pending testcase is:
gdb.dwarf2/pr11465.exp
[this]
This attached patch.
dw2-modula2-self-type.exp dw2-bad-parameter-type.exp pr11465.exp
2d04d865^ CRASH pass unaware:pass
[modula2]
42284fdf^ pass CRASH unaware:FAIL
[physname]
7e8e956c^ pass CRASH CRASH
[readerror]
HEAD pass pass FAIL
HEAD+[this] pass pass CRASH
HEAD+[delay] pass pass pass
[delay][this] pass pass pass
Therefore the patch of mine [readerror] turned CRASH->FAIL in some cases. The
FAIL case is difficult to understand and occurs only in very rare C++ cases
(one can -readnow libwebkit.so) so it could hide for a long time the [delay]
bug confusing C++ debugging.
The purpose of this patch is to make GDB crash again when the [delay] fix is
not applied. It has been a regression GDB no longer crashed due to its buggy
code [physname]-before-[delay].
No regressions on {x86_64,x86_64-m32,i686}-fedora12-linux-gnu.
Thanks,
Jan
gdb/
2010-04-21 Jan Kratochvil <jan.kratochvil@redhat.com>
* dwarf2read.c: Include exceptions.h.
(read_subroutine_type): Move void_type into a more inner block. New
variable e. Wrap a die_type call by TRY_CATCH. Delay parameters
filling only to the failure exit path.
gdb/testsuite/
2010-04-21 Jan Kratochvil <jan.kratochvil@redhat.com>
* gdb.dwarf2/dw2-modula2-self-type.exp,
gdb.dwarf2/dw2-modula2-self-type.S: New.
--- a/gdb/dwarf2read.c
+++ b/gdb/dwarf2read.c
@@ -51,6 +51,7 @@
#include "typeprint.h"
#include "jv-lang.h"
#include "psympriv.h"
+#include "exceptions.h"
#include <fcntl.h>
#include "gdb_string.h"
@@ -5943,7 +5944,6 @@ read_subroutine_type (struct die_info *die, struct dwarf2_cu *cu)
if (die->child != NULL)
{
- struct type *void_type = objfile_type (cu->objfile)->builtin_void;
struct die_info *child_die;
int nparams, iparams;
@@ -5966,17 +5966,14 @@ read_subroutine_type (struct die_info *die, struct dwarf2_cu *cu)
TYPE_FIELDS (ftype) = (struct field *)
TYPE_ZALLOC (ftype, nparams * sizeof (struct field));
- /* TYPE_FIELD_TYPE must never be NULL. Pre-fill the array to ensure it
- even if we error out during the parameters reading below. */
- for (iparams = 0; iparams < nparams; iparams++)
- TYPE_FIELD_TYPE (ftype, iparams) = void_type;
-
iparams = 0;
child_die = die->child;
while (child_die && child_die->tag)
{
if (child_die->tag == DW_TAG_formal_parameter)
{
+ volatile struct gdb_exception e;
+
/* Dwarf2 has no clean way to discern C++ static and non-static
member functions. G++ helps GDB by marking the first
parameter for non-static member functions (which is the
@@ -5998,7 +5995,35 @@ read_subroutine_type (struct die_info *die, struct dwarf2_cu *cu)
TYPE_FIELD_ARTIFICIAL (ftype, iparams) = 1;
}
}
- TYPE_FIELD_TYPE (ftype, iparams) = die_type (child_die, cu);
+
+ TRY_CATCH (e, RETURN_MASK_ALL)
+ {
+ TYPE_FIELD_TYPE (ftype, iparams) = die_type (child_die, cu);
+ }
+ if (e.reason < 0)
+ {
+ struct type *void_type;
+
+ void_type = objfile_type (cu->objfile)->builtin_void;
+
+ /* TYPE_FIELD_TYPE must never be NULL. As this TYPE has been
+ already installed by set_die_type above we can no longer
+ withdraw it. At least fill-in the parameters types by
+ stub types to ensure its consumers will not crash on it
+ later.
+
+ On the other hand do not fill in the parameters types in
+ advance as the DWARF reader is fragile regarding DIEs
+ reading order and we want the possible ordering bugs to be
+ caught. If anyone tries to access the TYPE parameters
+ before this function finalizes TYPE it should at least
+ crash. Filling in the parameters types in advance could
+ make the early readers quietly interpret this type as with
+ no (void) parameters. */
+ for (; iparams < nparams; iparams++)
+ TYPE_FIELD_TYPE (ftype, iparams) = void_type;
+ throw_exception (e);
+ }
iparams++;
}
child_die = sibling_die (child_die);
--- /dev/null
+++ b/gdb/testsuite/gdb.dwarf2/dw2-modula2-self-type.S
@@ -0,0 +1,123 @@
+/* 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 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/>. */
+
+/* Compiled from:
+ MODULE m;
+ TYPE t = PROCEDURE (t);
+ VAR v: t;
+ BEGIN
+ END m.
+ But "v" has been removed afterwards. */
+
+ .data
+v: .long 0
+
+ .section .debug_info
+d:
+ .long .Ldebug_info_end - 1f /* Length of Compilation Unit Info */
+1:
+ .2byte 0x3 /* DWARF version number */
+ .long .Ldebug_abbrev0 /* Offset Into Abbrev. Section */
+ .byte 0x4 /* Pointer Size (in bytes) */
+dieb:
+ .uleb128 0x1 /* (DIE (0xb) DW_TAG_compile_unit) */
+ .long .LASF0 /* DW_AT_producer */
+ .byte 0xa /* DW_AT_language = DW_LANG_Modula2 */
+ .long .LASF1 /* DW_AT_name: "2.mod" */
+ .long .LASF2 /* DW_AT_comp_dir: "" */
+
+die210:
+ .uleb128 0x5 # (DIE (0x210) DW_TAG_subroutine_type)
+die215:
+ .uleb128 0x6 # (DIE (0x215) DW_TAG_formal_parameter)
+ .long die21b-d # DW_AT_type
+ .byte 0x0 # end of children of DIE 0x210
+die21b:
+ .uleb128 0x7 # (DIE (0x21b) DW_TAG_pointer_type)
+ .byte 0x4 # DW_AT_byte_size
+ .long die210-d # DW_AT_type
+die221:
+ .uleb128 0x8 # (DIE (0x221) DW_TAG_variable)
+ .ascii "v\0" # DW_AT_name
+ .long die21b-d # DW_AT_type
+ .byte 2f-1f # DW_AT_location
+1: .byte 0x3 # DW_OP_addr
+ .long v
+2:
+
+ .byte 0x0 # end of children of DIE 0xb
+.Ldebug_info_end:
+ .section .debug_abbrev
+.Ldebug_abbrev0:
+
+ .uleb128 0x1 /* (abbrev code) */
+ .uleb128 0x11 /* (TAG: DW_TAG_compile_unit) */
+ .byte 0x1 /* DW_children_yes */
+ .uleb128 0x25 /* (DW_AT_producer) */
+ .uleb128 0xe /* (DW_FORM_strp) */
+ .uleb128 0x13 /* (DW_AT_language) */
+ .uleb128 0xb /* (DW_FORM_data1) */
+ .uleb128 0x3 /* (DW_AT_name) */
+ .uleb128 0xe /* (DW_FORM_strp) */
+ .uleb128 0x1b /* (DW_AT_comp_dir) */
+ .uleb128 0xe /* (DW_FORM_strp) */
+ .byte 0x0
+ .byte 0x0
+
+ .uleb128 0x5 # (abbrev code)
+ .uleb128 0x15 # (TAG: DW_TAG_subroutine_type)
+ .byte 0x1 # DW_children_yes
+ .byte 0x0
+ .byte 0x0
+
+ .uleb128 0x6 # (abbrev code)
+ .uleb128 0x5 # (TAG: DW_TAG_formal_parameter)
+ .byte 0x0 # DW_children_no
+ .uleb128 0x49 # (DW_AT_type)
+ .uleb128 0x13 # (DW_FORM_ref4)
+ .byte 0x0
+ .byte 0x0
+
+ .uleb128 0x7 # (abbrev code)
+ .uleb128 0xf # (TAG: DW_TAG_pointer_type)
+ .byte 0x0 # DW_children_no
+ .uleb128 0xb # (DW_AT_byte_size)
+ .uleb128 0xb # (DW_FORM_data1)
+ .uleb128 0x49 # (DW_AT_type)
+ .uleb128 0x13 # (DW_FORM_ref4)
+ .byte 0x0
+ .byte 0x0
+
+ .uleb128 0x8 # (abbrev code)
+ .uleb128 0x34 # (TAG: DW_TAG_variable)
+ .byte 0x0 # DW_children_no
+ .uleb128 0x3 # (DW_AT_name)
+ .uleb128 0x8 # (DW_FORM_string)
+ .uleb128 0x49 # (DW_AT_type)
+ .uleb128 0x13 # (DW_FORM_ref4)
+ .uleb128 0x2 # (DW_AT_location)
+ .uleb128 0xa # (DW_FORM_block1)
+ .byte 0x0
+ .byte 0x0
+
+ .byte 0x0
+
+ .section .debug_str
+.LASF1:
+ .string "2.mod"
+.LASF0:
+ .string "GNU Modula-2 0.78 (20100402) grafted onto GCC 4.1.2"
+.LASF2:
+ .string ""
--- /dev/null
+++ b/gdb/testsuite/gdb.dwarf2/dw2-modula2-self-type.exp
@@ -0,0 +1,48 @@
+# 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 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 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-modula2-self-type"
+set srcfile ${testfile}.S
+set executable ${testfile}.x
+set binfile ${objdir}/${subdir}/${executable}
+
+# First try referencing DW_AT_frame_base which is not defined.
+if { [gdb_compile "${srcdir}/${subdir}/${srcfile}" "${binfile}" object {}] != "" } {
+ return -1
+}
+
+clean_restart $executable
+
+# C language would just naively print:
+# type = void (*)(void (*)(void (*)(void (*)(void (*)(...
+# While modula-2 prints:
+# type = POINTER TO PROCEDURE
+gdb_test "set language modula-2"
+
+# The first access (as we do not use -readnow) crashes GDB.
+gdb_test "ptype v"
+
+gdb_test "p 1" " = 1" "alive"