gdb-gcc46-typedef.patch

   1 http://sourceware.org/ml/gdb-patches/2011-04/msg00154.html
   2 Subject: [patch] Workaround buggy GCC PR 47510 produced code
   3
   4 Hi,
   5
   6 GCC PR debug/47510 is already fixed and GDB has the proper support for it:
   7         RFC: update for GCC PR 47510
   8         http://sourceware.org/ml/gdb-patches/2011-03/msg00916.html
   9
  10 Still FSF GDB HEAD will crash on a binary produced by older/buggy GCC:
  11         Reading symbols from .../gcc46.o...dwarf2read.c:9329: internal-error: could not find partial DIE 0x9a in cache [from module .../gcc46.o]
  12
  13 Which may not give much clue to the user.
  14
  15 The proposed patch could make false warnings if any code out there has
  16 DW_TAG_typedef with children, it does not check for specific GCC versions.
  17 Still such DWARF is invalid, although in such case complaint() would be more
  18 appropriate than warning().  Does it make sense to differentiate it?
  19
  20 No regressions on {x86_64,x86_64-m32,i686}-fedora15-linux-gnu.
  21
  22
  23 Thanks,
  24 Jan
  25
  26
  27 gdb/
  28 2011-04-11  Jan Kratochvil  <jan.kratochvil@redhat.com>
  29
  30         * dwarf2read.c (struct dwarf2_per_objfile): New field
  31         typedef_children_warning_printed.
  32         (load_partial_dies): Read in any children of DW_TAG_typedef with
  33         a warning in such case.
  34
  35 gdb/testsuite/
  36 2011-04-11  Jan Kratochvil  <jan.kratochvil@redhat.com>
  37
  38         * gdb.dwarf2/dw2-typedef-children.S: New file.
  39         * gdb.dwarf2/dw2-typedef-children.exp: New file.
  40
  41 --- a/gdb/dwarf2read.c
  42 +++ b/gdb/dwarf2read.c
  43 @@ -209,6 +209,9 @@ struct dwarf2_per_objfile
  44       or we are faking it for OBJF_READNOW's sake.  */
  45    unsigned char using_index;
  46
  47 +  /* Print the GCC PR debug/47510 warning only once per objfile.  */
  48 +  unsigned typedef_children_warning_printed : 1;
  49 +
  50    /* The mapped index, or NULL if .gdb_index is missing or not being used.  */
  51    struct mapped_index *index_table;
  52
  53 @@ -8951,7 +8954,7 @@ load_partial_dies (bfd *abfd, gdb_byte *buffer, gdb_byte *info_ptr,
  54        if (parent_die == NULL
  55           && part_die->has_specification == 0
  56           && part_die->is_declaration == 0
  57 -         && (part_die->tag == DW_TAG_typedef
  58 +         && ((part_die->tag == DW_TAG_typedef && !part_die->has_children)
  59               || part_die->tag == DW_TAG_base_type
  60               || part_die->tag == DW_TAG_subrange_type))
  61         {
  62 @@ -8964,6 +8967,20 @@ load_partial_dies (bfd *abfd, gdb_byte *buffer, gdb_byte *info_ptr,
  63           continue;
  64         }
  65
  66 +      /* The exception for DW_TAG_typedef with has_children above is
  67 +        a workaround of GCC PR debug/47510.  GDB crashed on broken GCC output
  68 +        as it skipped children of DW_TAG_typedef by the shortcut above and
  69 +        then it could not find the child DIEs referenced later.  */
  70 +
  71 +      if (!dwarf2_per_objfile->typedef_children_warning_printed
  72 +         && part_die->tag == DW_TAG_typedef && part_die->has_children)
  73 +       {
  74 +         warning (_("DW_TAG_typedef has childen - GCC PR debug/47510 bug "
  75 +                    "- DIE at 0x%x [in module %s]"),
  76 +                  part_die->offset, cu->objfile->name);
  77 +         dwarf2_per_objfile->typedef_children_warning_printed = 1;
  78 +       }
  79 +
  80        /* If we're at the second level, and we're an enumerator, and
  81          our parent has no specification (meaning possibly lives in a
  82          namespace elsewhere), then we can add the partial symbol now
  83 --- /dev/null
  84 +++ b/gdb/testsuite/gdb.dwarf2/dw2-typedef-children.S
  85 @@ -0,0 +1,92 @@
  86 +/* This testcase is part of GDB, the GNU debugger.
  87 +
  88 +   Copyright 2011 Free Software Foundation, Inc.
  89 +
  90 +   This program is free software; you can redistribute it and/or modify
  91 +   it under the terms of the GNU General Public License as published by
  92 +   the Free Software Foundation; either version 3 of the License, or
  93 +   (at your option) any later version.
  94 +
  95 +   This program is distributed in the hope that it will be useful,
  96 +   but WITHOUT ANY WARRANTY; without even the implied warranty of
  97 +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  98 +   GNU General Public License for more details.
  99 +
 100 +   You should have received a copy of the GNU General Public License
 101 +   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 102 +
 103 +/* Debug information */
 104 +
 105 +       .section .debug_info
 106 +.Lcu1_begin:
 107 +       /* CU header */
 108 +       .4byte  .Lcu1_end - .Lcu1_start         /* Length of Compilation Unit */
 109 +.Lcu1_start:
 110 +       .2byte  2                               /* DWARF Version */
 111 +       .4byte  .Labbrev1_begin                 /* Offset into abbrev section */
 112 +       .byte   4                               /* Pointer size */
 113 +
 114 +       /* CU die */
 115 +       .uleb128 1                              /* Abbrev: DW_TAG_compile_unit */
 116 +       .ascii  "file1.txt\0"                   /* DW_AT_name */
 117 +       .ascii  "GNU C 3.3.3\0"                 /* DW_AT_producer */
 118 +       .byte   1                               /* DW_AT_language (C) */
 119 +
 120 +.Ltype_int:
 121 +       .uleb128        2                       /* Abbrev: DW_TAG_base_type */
 122 +       .ascii          "int\0"                 /* DW_AT_name */
 123 +       .byte           4                       /* DW_AT_byte_size */
 124 +       .byte           5                       /* DW_AT_encoding */
 125 +
 126 +       .uleb128        0x3                     /* (DIE (0x38) DW_TAG_typedef) */
 127 +       .ascii          "new\0"                 /* DW_AT_name */
 128 +       .long           .Ltype_int - .Lcu1_begin        /* DW_AT_type */
 129 +
 130 +       .uleb128        2                       /* Abbrev: DW_TAG_base_type */
 131 +       .ascii          "int\0"                 /* DW_AT_name */
 132 +       .byte           4                       /* DW_AT_byte_size */
 133 +       .byte           5                       /* DW_AT_encoding */
 134 +
 135 +       .uleb128        0                       /* End of DW_TAG_typedef */
 136 +       .uleb128        0                       /* End of DW_TAG_compile_unit */
 137 +.Lcu1_end:
 138 +
 139 +/* Abbrev table */
 140 +       .section .debug_abbrev
 141 +.Labbrev1_begin:
 142 +       .uleb128        1                       /* Abbrev code */
 143 +       .uleb128        0x11                    /* DW_TAG_compile_unit */
 144 +       .byte           1                       /* has_children */
 145 +       .uleb128        0x3                     /* DW_AT_name */
 146 +       .uleb128        0x8                     /* DW_FORM_string */
 147 +       .uleb128        0x25                    /* DW_AT_producer */
 148 +       .uleb128        0x8                     /* DW_FORM_string */
 149 +       .uleb128        0x13                    /* DW_AT_language */
 150 +       .uleb128        0xb                     /* DW_FORM_data1 */
 151 +       .byte           0x0                     /* Terminator */
 152 +       .byte           0x0                     /* Terminator */
 153 +
 154 +       .uleb128        2                       /* Abbrev code */
 155 +       .uleb128        0x24                    /* DW_TAG_base_type */
 156 +       .byte           0                       /* has_children */
 157 +       .uleb128        0x3                     /* DW_AT_name */
 158 +       .uleb128        0x8                     /* DW_FORM_string */
 159 +       .uleb128        0xb                     /* DW_AT_byte_size */
 160 +       .uleb128        0xb                     /* DW_FORM_data1 */
 161 +       .uleb128        0x3e                    /* DW_AT_encoding */
 162 +       .uleb128        0xb                     /* DW_FORM_data1 */
 163 +       .byte           0x0                     /* Terminator */
 164 +       .byte           0x0                     /* Terminator */
 165 +
 166 +       .uleb128        0x3                     /* (abbrev code) */
 167 +       .uleb128        0x16                    /* (TAG: DW_TAG_typedef) */
 168 +       .byte           0x1                     /* DW_children_yes */
 169 +       .uleb128        0x3                     /* (DW_AT_name) */
 170 +       .uleb128        0x8                     /* (DW_FORM_string) */
 171 +       .uleb128        0x49                    /* (DW_AT_type) */
 172 +       .uleb128        0x13                    /* (DW_FORM_ref4) */
 173 +       .byte           0x0
 174 +       .byte           0x0
 175 +
 176 +       .byte           0x0                     /* Terminator */
 177 +       .byte           0x0                     /* Terminator */
 178 --- /dev/null
 179 +++ b/gdb/testsuite/gdb.dwarf2/dw2-typedef-children.exp
 180 @@ -0,0 +1,37 @@
 181 +# Copyright 2011 Free Software Foundation, Inc.
 182 +
 183 +# This program is free software; you can redistribute it and/or modify
 184 +# it under the terms of the GNU General Public License as published by
 185 +# the Free Software Foundation; either version 3 of the License, or
 186 +# (at your option) any later version.
 187 +#
 188 +# This program is distributed in the hope that it will be useful,
 189 +# but WITHOUT ANY WARRANTY; without even the implied warranty of
 190 +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 191 +# GNU General Public License for more details.
 192 +#
 193 +# You should have received a copy of the GNU General Public License
 194 +# along with this program.  If not, see <http://www.gnu.org/licenses/>.
 195 +load_lib dwarf.exp
 196 +
 197 +# Note: Inspired from dw2-basic.exp.
 198 +
 199 +# This test can only be run on targets which support DWARF-2 and use gas.
 200 +if {![dwarf2_support]} {
 201 +    return 0
 202 +}
 203 +
 204 +set testfile "dw2-typedef-children"
 205 +set srcfile ${testfile}.S
 206 +set binfile ${objdir}/${subdir}/${testfile}.x
 207 +
 208 +if  { [gdb_compile "${srcdir}/${subdir}/${srcfile}" "${binfile}" object {nodebug}] != "" } {
 209 +    return -1
 210 +}
 211 +
 212 +gdb_exit
 213 +gdb_start
 214 +
 215 +gdb_test "file $binfile" \
 216 +        "warning: DW_TAG_typedef has childen - GCC PR debug/47510 bug - DIE at .*" \
 217 +        "warning message"
 218