[patch] Fix crash on NULL function's TYPE_FIELD_TYPE

Jan Kratochvil
2010-03-30T08:38:34Z

Hi,

seen one possibility of a crash.

#0 c_print_type (type=0x0, ...)
#1 in c_type_print_args (type=0xfceb890,

(The real reason of a reported GDB crash was different, though.)

Thanks,
Jan

gdb/
2010-03-30 Jan Kratochvil <jan.kratochvil@redhat.com>

Fix crash on reading wrong function declaration DWARF.
* dwarf2read.c (read_subroutine_type): New variable void_type.
Pre-fill all TYPE_FIELD_TYPEs. Move nparams and iparams initialization
more close to their use.

gdb/testsuite/
2010-03-30 Jan Kratochvil <jan.kratochvil@redhat.com>

* gdb.dwarf2/dw2-bad-parameter-type.exp,
gdb.dwarf2/dw2-bad-parameter-type.S: New.

--- a/gdb/dwarf2read.c
+++ b/gdb/dwarf2read.c
@@ -5938,13 +5938,14 @@ 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 = 0;
- int iparams = 0;
+ int nparams, iparams;

/* Count the number of parameters.
FIXME: GDB currently ignores vararg functions, but knows about
vararg member functions. */
+ nparams = 0;
child_die = die->child;
while (child_die && child_die->tag)
{
@@ -5960,6 +5961,12 @@ 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)
{
--- /dev/null
+++ b/gdb/testsuite/gdb.dwarf2/dw2-bad-parameter-type.S
@@ -0,0 +1,73 @@
+/* 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/>. */
+
+ .section .debug_info
+debug_start:
+ .long debug_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) */
+ .uleb128 0x1 /* (DIE (0xb) DW_TAG_compile_unit) */
+ .ascii "GNU C 4.4.3\0" /* DW_AT_producer */
+ .byte 0x1 /* DW_AT_language */
+ .ascii "1.c\0" /* DW_AT_name */
+ .uleb128 0x4 /* (DIE (0x3c) DW_TAG_subprogram) */
+ .ascii "f\0" /* DW_AT_name */
+/* Value 0 would require has_section_at_zero != 0 (which is true, though). */
+ .long 1 /* DW_AT_low_pc */
+ .long 2 /* DW_AT_high_pc */
+ .byte 0x1 /* DW_AT_prototyped */
+ .uleb128 0x5 /* (DIE (0x42) DW_TAG_formal_parameter) */
+/* Invalid value. */
+ .long 0x0 /* DW_AT_type */
+ .byte 0x0 /* end of children of DIE 0x3c */
+ .byte 0x0 /* end of children of DIE 0xb */
+debug_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 0x8 /* (DW_FORM_string) */
+ .uleb128 0x13 /* (DW_AT_language) */
+ .uleb128 0xb /* (DW_FORM_data1) */
+ .uleb128 0x3 /* (DW_AT_name) */
+ .uleb128 0x8 /* (DW_FORM_string) */
+ .byte 0x0
+ .byte 0x0
+ .uleb128 0x4 /* (abbrev code) */
+ .uleb128 0x2e /* (TAG: DW_TAG_subprogram) */
+ .byte 0x1 /* DW_children_yes */
+ .uleb128 0x3 /* (DW_AT_name) */
+ .uleb128 0x8 /* (DW_FORM_string) */
+ .uleb128 0x11 /* (DW_AT_low_pc) */
+ .uleb128 0x1 /* (DW_FORM_addr) */
+ .uleb128 0x12 /* (DW_AT_high_pc) */
+ .uleb128 0x1 /* (DW_FORM_addr) */
+ .uleb128 0x27 /* (DW_AT_prototyped) */
+ .uleb128 0xc /* (DW_FORM_flag) */
+ .byte 0x0
+ .byte 0x0
+ .uleb128 0x5 /* (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
+ .byte 0x0
--- /dev/null
+++ b/gdb/testsuite/gdb.dwarf2/dw2-bad-parameter-type.exp
@@ -0,0 +1,44 @@
+# 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-bad-parameter-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
+
+# The first access (as we do not use -readnow) prints some:
+# Dwarf Error: Cannot find DIE at 0x0 referenced from DIE at 0x29 [in module ...]
+gdb_test "ptype f"
+
+gdb_test "ptype f"
+gdb_test "p 5" " = 5" "is alive"