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Re: [PATCH] Fix bug using dwarf_next_unit to iterate over .debug_types
- From: Mark Wielaard <mjw at redhat dot com>
- To: elfutils-devel at lists dot fedorahosted dot org
- Date: Wed, 21 Mar 2012 16:45:18 +0100
- Subject: Re: [PATCH] Fix bug using dwarf_next_unit to iterate over .debug_types
On Wed, 2012-03-21 at 08:54 -0600, Tom Tromey wrote:
> * libdw_findcu.c (findcu_cb): Move earlier.
> (__libdw_intern_next_unit): Add new CU to search tree here...
> (__libdw_findcu): ... not here.
>
> * typeiter.c: New file.
> * run-typeiter.sh: New file.
> * testfile59.bz2: New file.
> * Makefile.am (noinst_PROGRAMS): Add typeiter.
> (TESTS): Add run-typeiter.sh.
> (EXTRA_DIST): Add run-typeiter.sh, testfile59.bz2.
> (typeiter_LDADD): New variable.
Thanks for adding the testcase. I tested that it fails before and
succeeds after the fix. Also the systemtap testcase works with this.
Since roland already OKed the code I pushed it for you with one small
change. I added the actual source that was used to create the test
binary to the testcase as comment in case anybody wants to recreate it
in the future.
Cheers,
Mark
# struct s1
# {
# char c;
# short s;
# int i;
# long l;
# float f;
# double d;
# };
#
# s1 S1;
#
# int func (s1 *p)
# {
# return p->i;
# }
#
# int main()
# {
# return func (&S1);
# }
#
# g++ -gdwarf-4 -g -fdebug-types-section
> If you call dwarf_next_unit to iterate over .debug_types, then call
> dwarf_offdie_types, you can see a failure if some earlier call
> happened to call __libdw_intern_next_unit via dwarf_formref_die.
>
> What happens is that __libdw_intern_next_unit updates the Dwarf's
> next_tu_offset, but does not add the TU to the TU search tree. So,
> the call to dwarf_offdie_types does not find the TU in the tree, and
> will not search any more, causing a failure.
>
> This fix changes __libdw_intern_next_unit to add the TU to the search
> tree, rather than relying on __libdw_findcu to do it.
> ---
> libdw/ChangeLog | 6 +++
> libdw/libdw_findcu.c | 68 ++++++++++++++++-----------------
> tests/ChangeLog | 10 +++++
> tests/Makefile.am | 8 ++-
> tests/run-typeiter.sh | 34 +++++++++++++++++
> tests/testfile59.bz2 | Bin 0 -> 3097 bytes
> tests/typeiter.c | 98 +++++++++++++++++++++++++++++++++++++++++++++++++
> 7 files changed, 186 insertions(+), 38 deletions(-)
> create mode 100755 tests/run-typeiter.sh
> create mode 100755 tests/testfile59.bz2
> create mode 100644 tests/typeiter.c
>
> diff --git a/libdw/ChangeLog b/libdw/ChangeLog
> index 98b67f4..f96c0d1 100644
> --- a/libdw/ChangeLog
> +++ b/libdw/ChangeLog
> @@ -1,3 +1,9 @@
> +2012-03-19 Tom Tromey <tromey@redhat.com>
> +
> + * libdw_findcu.c (findcu_cb): Move earlier.
> + (__libdw_intern_next_unit): Add new CU to search tree here...
> + (__libdw_findcu): ... not here.
> +
> 2012-01-31 Mark Wielaard <mjw@redhat.com>
>
> * dwarf_formudata.c (dwarf_formudata): Handle DW_FORM_sec_offset.
> diff --git a/libdw/libdw_findcu.c b/libdw/libdw_findcu.c
> index 8e5f9e9..83c96ba 100644
> --- a/libdw/libdw_findcu.c
> +++ b/libdw/libdw_findcu.c
> @@ -56,6 +56,31 @@
> #include <search.h>
> #include "libdwP.h"
>
> +static int
> +findcu_cb (const void *arg1, const void *arg2)
> +{
> + struct Dwarf_CU *cu1 = (struct Dwarf_CU *) arg1;
> + struct Dwarf_CU *cu2 = (struct Dwarf_CU *) arg2;
> +
> + /* Find out which of the two arguments is the search value. It has
> + end offset 0. */
> + if (cu1->end == 0)
> + {
> + if (cu1->start < cu2->start)
> + return -1;
> + if (cu1->start >= cu2->end)
> + return 1;
> + }
> + else
> + {
> + if (cu2->start < cu1->start)
> + return 1;
> + if (cu2->start >= cu1->end)
> + return -1;
> + }
> +
> + return 0;
> +}
>
> struct Dwarf_CU *
> internal_function
> @@ -65,6 +90,7 @@ __libdw_intern_next_unit (dbg, debug_types)
> {
> Dwarf_Off *const offsetp
> = debug_types ? &dbg->next_tu_offset : &dbg->next_cu_offset;
> + void **tree = debug_types ? &dbg->tu_tree : &dbg->cu_tree;
>
> Dwarf_Off oldoff = *offsetp;
> uint16_t version;
> @@ -105,34 +131,16 @@ __libdw_intern_next_unit (dbg, debug_types)
> newp->lines = NULL;
> newp->locs = NULL;
>
> - return newp;
> -}
> -
> -
> -static int
> -findcu_cb (const void *arg1, const void *arg2)
> -{
> - struct Dwarf_CU *cu1 = (struct Dwarf_CU *) arg1;
> - struct Dwarf_CU *cu2 = (struct Dwarf_CU *) arg2;
> -
> - /* Find out which of the two arguments is the search value. It has
> - end offset 0. */
> - if (cu1->end == 0)
> + /* Add the new entry to the search tree. */
> + if (tsearch (newp, tree, findcu_cb) == NULL)
> {
> - if (cu1->start < cu2->start)
> - return -1;
> - if (cu1->start >= cu2->end)
> - return 1;
> - }
> - else
> - {
> - if (cu2->start < cu1->start)
> - return 1;
> - if (cu2->start >= cu1->end)
> - return -1;
> + /* Something went wrong. Undo the operation. */
> + *offsetp = oldoff;
> + __libdw_seterrno (DWARF_E_NOMEM);
> + return NULL;
> }
>
> - return 0;
> + return newp;
> }
>
> struct Dwarf_CU *
> @@ -160,20 +168,10 @@ __libdw_findcu (dbg, start, debug_types)
> /* No. Then read more CUs. */
> while (1)
> {
> - Dwarf_Off oldoff = *next_offset;
> struct Dwarf_CU *newp = __libdw_intern_next_unit (dbg, debug_types);
> if (newp == NULL)
> return NULL;
>
> - /* Add the new entry to the search tree. */
> - if (tsearch (newp, tree, findcu_cb) == NULL)
> - {
> - /* Something went wrong. Undo the operation. */
> - *next_offset = oldoff;
> - __libdw_seterrno (DWARF_E_NOMEM);
> - return NULL;
> - }
> -
> /* Is this the one we are looking for? */
> if (start < *next_offset)
> // XXX Match exact offset.
> diff --git a/tests/ChangeLog b/tests/ChangeLog
> index a782591..8d2b83f 100644
> --- a/tests/ChangeLog
> +++ b/tests/ChangeLog
> @@ -1,3 +1,13 @@
> +2012-03-21 Tom Tromey <tromey@redhat.com>
> +
> + * typeiter.c: New file.
> + * run-typeiter.sh: New file.
> + * testfile59.bz2: New file.
> + * Makefile.am (noinst_PROGRAMS): Add typeiter.
> + (TESTS): Add run-typeiter.sh.
> + (EXTRA_DIST): Add run-typeiter.sh, testfile59.bz2.
> + (typeiter_LDADD): New variable.
> +
> 2012-02-21 Kurt Roeckx <kurt@roeckx.be>
>
> * run-alldts.sh: testrun ./alldts.
> diff --git a/tests/Makefile.am b/tests/Makefile.am
> index 3074c89..f2c211b 100644
> --- a/tests/Makefile.am
> +++ b/tests/Makefile.am
> @@ -58,7 +58,7 @@ noinst_PROGRAMS = arextract arsymtest newfile saridx scnnames sectiondump \
> dwfl-addr-sect dwfl-bug-report early-offscn \
> dwfl-bug-getmodules dwarf-getmacros addrcfi \
> test-flag-nobits dwarf-getstring rerequest_tag \
> - alldts md5-sha1-test
> + alldts md5-sha1-test typeiter
> asm_TESTS = asm-tst1 asm-tst2 asm-tst3 asm-tst4 asm-tst5 \
> asm-tst6 asm-tst7 asm-tst8 asm-tst9
>
> @@ -86,7 +86,7 @@ TESTS = run-arextract.sh run-arsymtest.sh newfile test-nlist \
> run-disasm-x86.sh run-disasm-x86-64.sh \
> run-early-offscn.sh run-dwarf-getmacros.sh \
> run-test-flag-nobits.sh run-prelink-addr-test.sh \
> - run-dwarf-getstring.sh run-rerequest_tag.sh
> + run-dwarf-getstring.sh run-rerequest_tag.sh run-typeiter.sh
> # run-show-ciefde.sh
>
> if !STANDALONE
> @@ -161,7 +161,8 @@ EXTRA_DIST = run-arextract.sh run-arsymtest.sh \
> testfile55-32.bz2 testfile55-32.debug.bz2 \
> testfile55-32.prelink.bz2 testfile55-64.bz2 \
> testfile55-64.debug.bz2 testfile55-64.prelink.bz2 \
> - testfile56.bz2 testfile57.bz2 testfile58.bz2
> + testfile56.bz2 testfile57.bz2 testfile58.bz2 \
> + run-typeiter.sh testfile59.bz2
>
> installed_TESTS_ENVIRONMENT = libdir=$(DESTDIR)$(libdir) \
> bindir=$(DESTDIR)$(bindir) \
> @@ -258,6 +259,7 @@ test_flag_nobits_LDADD = $(libelf) $(libmudflap)
> rerequest_tag_LDADD = $(libdw) $(libmudflap)
> alldts_LDADD = $(libebl) $(libelf) $(libmudflap)
> md5_sha1_test_LDADD = $(libeu)
> +typeiter_LDADD = $(libdw) $(libelf) $(libmudflap)
>
> if GCOV
> check: check-am coverage
> diff --git a/tests/run-typeiter.sh b/tests/run-typeiter.sh
> new file mode 100755
> index 0000000..34a4eb3
> --- /dev/null
> +++ b/tests/run-typeiter.sh
> @@ -0,0 +1,34 @@
> +#! /bin/sh
> +# Copyright (C) 2012 Red Hat, Inc.
> +# This file is part of Red Hat elfutils.
> +#
> +# Red Hat elfutils 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; version 2 of the License.
> +#
> +# Red Hat elfutils 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 Red Hat elfutils; if not, write to the Free Software Foundation,
> +# Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301 USA.
> +#
> +# Red Hat elfutils is an included package of the Open Invention Network.
> +# An included package of the Open Invention Network is a package for which
> +# Open Invention Network licensees cross-license their patents. No patent
> +# license is granted, either expressly or impliedly, by designation as an
> +# included package. Should you wish to participate in the Open Invention
> +# Network licensing program, please visit www.openinventionnetwork.com
> +# <http://www.openinventionnetwork.com>.
> +
> +. $srcdir/test-subr.sh
> +
> +testfiles testfile59
> +
> +testrun_compare ./typeiter testfile59 <<\EOF
> +ok
> +EOF
> +
> +exit 0
> diff --git a/tests/testfile59.bz2 b/tests/testfile59.bz2
> new file mode 100755
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> diff --git a/tests/typeiter.c b/tests/typeiter.c
> new file mode 100644
> index 0000000..184b00b
> --- /dev/null
> +++ b/tests/typeiter.c
> @@ -0,0 +1,98 @@
> +/* Copyright (C) 2012 Red Hat, Inc.
> + This file is part of Red Hat elfutils.
> +
> + Red Hat elfutils 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; version 2 of the License.
> +
> + Red Hat elfutils 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 Red Hat elfutils; if not, write to the Free Software Foundation,
> + Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301 USA.
> +
> + Red Hat elfutils is an included package of the Open Invention Network.
> + An included package of the Open Invention Network is a package for which
> + Open Invention Network licensees cross-license their patents. No patent
> + license is granted, either expressly or impliedly, by designation as an
> + included package. Should you wish to participate in the Open Invention
> + Network licensing program, please visit www.openinventionnetwork.com
> + <http://www.openinventionnetwork.com>. */
> +
> +#ifdef HAVE_CONFIG_H
> +# include <config.h>
> +#endif
> +
> +#include <fcntl.h>
> +#include ELFUTILS_HEADER(dw)
> +#include <stdio.h>
> +#include <unistd.h>
> +#include <dwarf.h>
> +
> +int
> +main (int argc, char *argv[])
> +{
> + for (int i = 1; i < argc; ++i)
> + {
> + int fd = open (argv[i], O_RDONLY);
> +
> + Dwarf *dbg = dwarf_begin (fd, DWARF_C_READ);
> + if (dbg != NULL)
> + {
> + Dwarf_Off off = 0;
> + size_t cuhl;
> + Dwarf_Off noff;
> +
> + while (dwarf_nextcu (dbg, off, &noff, &cuhl, NULL, NULL, NULL) == 0)
> + {
> + Dwarf_Die die_mem;
> + Dwarf_Die *die = dwarf_offdie (dbg, off + cuhl, &die_mem);
> +
> + Dwarf_Die iter_mem;
> + Dwarf_Die *iter = &iter_mem;
> + dwarf_child (die, &iter_mem);
> +
> + while (1)
> + {
> + if (dwarf_tag (iter) == DW_TAG_variable)
> + {
> + Dwarf_Attribute attr_mem;
> + Dwarf_Die form_mem;
> + dwarf_formref_die (dwarf_attr (iter, DW_AT_type,
> + &attr_mem),
> + &form_mem);
> + }
> +
> + if (dwarf_siblingof (iter, &iter_mem) != 0)
> + break;
> + }
> +
> + off = noff;
> + }
> +
> + off = 0;
> + uint64_t type_sig;
> +
> + while (dwarf_next_unit (dbg, off, &noff, &cuhl, NULL, NULL, NULL,
> + NULL, &type_sig, NULL) == 0)
> + {
> + Dwarf_Die die_mem;
> + Dwarf_Die *die = dwarf_offdie_types (dbg, off + cuhl, &die_mem);
> +
> + if (die == NULL)
> + printf ("fail\n");
> + else
> + printf ("ok\n");
> +
> + off = noff;
> + }
> +
> + dwarf_end (dbg);
> + }
> +
> + close (fd);
> + }
> +}