old-cross-binutils/gdb/testsuite/gdb.dwarf2/dw2-bad-mips-linkage-name.c

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dwarf2read.c: Check type of string valued attributes prior to decoding. This change introduces a new function, dwarf2_string_attr(), which is a wrapper for dwarf2_attr(). dwarf2read.c has been updated to call dwarf2_string_attr in most instances where a string-valued attribute is decoded to produce a string value. In most cases, it simplifies the code; in some instances, the complexity of the code remains unchanged. I performed this change by looking for instances where the result of DW_STRING was used in an assignment. Many of these had a pattern which (roughly) looks something like this: struct attribute *attr = NULL; attr = dwarf2_attr (die, name, cu); if (attr != NULL && DW_STRING (attr)) { const char *str; ... str = DW_STRING (attr); ... /* Use str in some fashion. */ } Code of this form is transformed to look like this instead: const char *str; str = dwarf2_string_attr (die, name, cu) if (str != NULL) { ... /* Use str in some fashion. */ ... } In addition to invoking dwarf2_attr() and DW_STRING(), dwarf2_string_attr() checks to make sure that the attribute's `form' field matches one of DW_FORM_strp, DW_FORM_string, or DW_FORM_GNU_strp_alt. If it does not match one of these forms, it will return a NULL value in addition to calling complaint(). An earlier version of this patch did this type checking for one particular instance where a string attribute was being decoded. The situation that I was attempting to handle in that earlier patch is this: The Texas Instruments compiler uses the encoding for DW_AT_MIPS_linkage_name for other purposes. TI uses the encoding, 0x2007, for TI_AT_TI_end_line which, unlike DW_AT_MIPS_linkage_name, does not have a string-typed value. In this instance, GDB was attempting to use an integer value as a string pointer, with predictable results. (GDB would die with a segmentation fault.) I've added a test which reproduces the problem that I was orignally wanting to fix. It uses DW_AT_MIPS_linkage name with an associate value which is a string, and again, where the value is a small integer. My test case causes GDB to segfault in an unpatched GDB. There will be two PASSes in a patched GDB. Unpatched GDB: (gdb) ptype f ERROR: Process no longer exists UNRESOLVED: gdb.dwarf2/dw2-bad-mips-linkage-name.exp: ptype f ERROR: Couldn't send ptype g to GDB. UNRESOLVED: gdb.dwarf2/dw2-bad-mips-linkage-name.exp: ptype g Patched GDB: (gdb) ptype f type = bool () (gdb) PASS: gdb.dwarf2/dw2-bad-mips-linkage-name.exp: ptype f ptype g type = bool () (gdb) PASS: gdb.dwarf2/dw2-bad-mips-linkage-name.exp: ptype g I see no regressions on an x86_64 native target. gdb/ChangeLog: * dwarf2read.c (dwarf2_string_attr): New function. (lookup_dwo_unit, process_psymtab_comp_unit_reader) (dwarf2_compute_name, dwarf2_physname, find_file_and_directory) (read_call_site_scope, namespace_name, guess_full_die_structure_name) (anonymous_struct_prefix, prepare_one_comp_unit): Use dwarf2_string_attr in place of dwarf2_attr and DW_STRING. gdb/testsuite/ChangeLog: * gdb.dwarf2/dw2-bad-mips-linkage-name.c: New file. * gdb.dwarf2/dw2-bad-mips-linkage-name.exp: New file.
2015-08-03 21:17:17 +00:00
/* This testcase is part of GDB, the GNU debugger.
Copyright 2015 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/>. */
/* Dummy main function. */
int
main (void)
{
asm ("main_label: .globl main_label");
return 0;
}
/* dummy f function, DWARF will describe arguments and type differently. */
int
f (char *x)
{
asm (".global f_end_lbl\nf_end_lbl:");
return 0;
}
/* dummy g function, DWARF will describe arguments and type differently. */
int
g (char *x)
{
asm (".global g_end_lbl\ng_end_lbl:");
return 0;
}