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[patch] Fix crash on NULL function's TYPE_FIELD_TYPE


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"


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