218 lines
7.0 KiB
Diff
218 lines
7.0 KiB
Diff
http://sourceware.org/ml/gdb-patches/2010-07/msg00237.html
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Subject: [patch] Fix regression on prelinked executables
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Hi,
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there is a regression since gdb-7.0 for a combination of:
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* prelinked
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* main executable
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* using separate debug info
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* using copy relocations
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It is since a patch for both PIE and (AFAIK) OSX support:
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[commit] syms_from_objfile: Relativize also MAINLINE
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http://sourceware.org/ml/gdb-patches/2010-01/msg00080.html
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which started to use problematic addr_info_make_relative even for main
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executables. prelink<->gdb discussion at:
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https://bugzilla.redhat.com/show_bug.cgi?id=614659
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Currently in the unfortunately executables GDB has invalid displcement for
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symbols in .bss:
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int bssvar, *bssvarp = &bssvar;
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(gdb) p &bssvar
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$1 = (int *) 0x600b54
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(gdb) p bssvarp
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$2 = (int *) 0x600b50
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<abstract-higher-point-of-view>
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addr_info_make_relative could just simply subtract entry point address and
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provide single CORE_ADDR objfile->offset (instead of the current
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section_offsets array with offsets specific for each section). Linux systems
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use always single offset for the whole objfile. AFAIK these per-section
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offsets are there for some embedded targets. Curiously GDB already uses at
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many places
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baseaddr = ANOFFSET (objfile->section_offsets, SECT_OFF_TEXT (objfile));
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instead of using offset for the appropriate section at that place and nobody
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complains.
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</abstract-higher-point-of-view>
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No regressions on {x86_64,x86_64-m32,i686}-fedora13-linux-gnu.
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Proposing for the gdb-7.2 branch. I had problems fixing up my crashing X.
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Thanks,
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Jan
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gdb/
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2010-07-15 Jan Kratochvil <jan.kratochvil@redhat.com>
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* symfile.c (addr_section_name): New function.
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(addrs_section_compar): Use it.
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(addr_info_make_relative): Use it. Move variable sect_name into a more
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inner block. Make ".dynbss" and ".sdynbss" checks more strict.
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gdb/testsuite/
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2010-07-15 Jan Kratochvil <jan.kratochvil@redhat.com>
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* gdb.base/prelink-lib.c (copyreloc): New initialized variable.
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* gdb.base/prelink.c (copyreloc, bssvar, bssvarp): New variables.
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(main): Use copyreloc.
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* gdb.base/prelink.exp (split debug of executable)
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(.dynbss vs. .bss address shift): New tests.
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--- a/gdb/symfile.c
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+++ b/gdb/symfile.c
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@@ -547,6 +547,23 @@ relative_addr_info_to_section_offsets (struct section_offsets *section_offsets,
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}
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}
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+/* Transform section name S for a name comparison. prelink can split section
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+ `.bss' into two sections `.dynbss' and `.bss' (in this order). Similarly
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+ prelink can split `.sbss' into `.sdynbss' and `.sbss'. Use virtual address
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+ of the new `.dynbss' (`.sdynbss') section as the adjacent new `.bss'
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+ (`.sbss') section has invalid (increased) virtual address. */
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+
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+static const char *
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+addr_section_name (const char *s)
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+{
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+ if (strcmp (s, ".dynbss") == 0)
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+ return ".bss";
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+ if (strcmp (s, ".sdynbss") == 0)
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+ return ".sbss";
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+
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+ return s;
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+}
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+
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/* qsort comparator for addrs_section_sort. Sort entries in ascending order by
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their (name, sectindex) pair. sectindex makes the sort by name stable. */
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@@ -557,7 +574,7 @@ addrs_section_compar (const void *ap, const void *bp)
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const struct other_sections *b = *((struct other_sections **) bp);
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int retval, a_idx, b_idx;
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- retval = strcmp (a->name, b->name);
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+ retval = strcmp (addr_section_name (a->name), addr_section_name (b->name));
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if (retval)
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return retval;
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@@ -641,14 +658,16 @@ addr_info_make_relative (struct section_addr_info *addrs, bfd *abfd)
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while (*addrs_sorted)
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{
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- const char *sect_name = (*addrs_sorted)->name;
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+ const char *sect_name = addr_section_name ((*addrs_sorted)->name);
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while (*abfd_addrs_sorted
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- && strcmp ((*abfd_addrs_sorted)->name, sect_name) < 0)
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+ && strcmp (addr_section_name ((*abfd_addrs_sorted)->name),
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+ sect_name) < 0)
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abfd_addrs_sorted++;
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if (*abfd_addrs_sorted
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- && strcmp ((*abfd_addrs_sorted)->name, sect_name) == 0)
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+ && strcmp (addr_section_name ((*abfd_addrs_sorted)->name),
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+ sect_name) == 0)
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{
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int index_in_addrs;
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@@ -676,7 +695,6 @@ addr_info_make_relative (struct section_addr_info *addrs, bfd *abfd)
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for (i = 0; i < addrs->num_sections && addrs->other[i].name; i++)
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{
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- const char *sect_name = addrs->other[i].name;
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struct other_sections *sect = addrs_to_abfd_addrs[i];
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if (sect)
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@@ -694,6 +712,9 @@ addr_info_make_relative (struct section_addr_info *addrs, bfd *abfd)
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}
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else
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{
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+ /* addr_section_name transformation is not used for SECT_NAME. */
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+ const char *sect_name = addrs->other[i].name;
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+
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/* This section does not exist in ABFD, which is normally
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unexpected and we want to issue a warning.
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@@ -704,12 +725,20 @@ addr_info_make_relative (struct section_addr_info *addrs, bfd *abfd)
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a warning. Shared libraries contain just the section
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".gnu.liblist" but it is not marked as loadable there. There is
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no other way to identify them than by their name as the sections
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- created by prelink have no special flags. */
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+ created by prelink have no special flags.
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+
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+ For the sections `.bss' and `.sbss' see addr_section_name. */
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if (!(strcmp (sect_name, ".gnu.liblist") == 0
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|| strcmp (sect_name, ".gnu.conflict") == 0
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- || strcmp (sect_name, ".dynbss") == 0
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- || strcmp (sect_name, ".sdynbss") == 0))
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+ || (strcmp (sect_name, ".bss") == 0
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+ && i > 0
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+ && strcmp (addrs->other[i - 1].name, ".dynbss") == 0
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+ && addrs_to_abfd_addrs[i - 1] != NULL)
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+ || (strcmp (sect_name, ".sbss") == 0
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+ && i > 0
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+ && strcmp (addrs->other[i - 1].name, ".sdynbss") == 0
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+ && addrs_to_abfd_addrs[i - 1] != NULL)))
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warning (_("section %s not found in %s"), sect_name,
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bfd_get_filename (abfd));
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--- a/gdb/testsuite/gdb.base/prelink-lib.c
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+++ b/gdb/testsuite/gdb.base/prelink-lib.c
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@@ -16,6 +16,8 @@
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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+int copyreloc = 1;
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+
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int
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g (void (*p)(void))
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{
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--- a/gdb/testsuite/gdb.base/prelink.c
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+++ b/gdb/testsuite/gdb.base/prelink.c
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@@ -18,6 +18,11 @@
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#include <stdio.h>
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+extern int copyreloc;
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+
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+/* Test GDB itself finds `&bssvar' right. */
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+static int bssvar, *bssvarp = &bssvar;
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+
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extern void (*h (void)) (void (*)(void));
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int
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@@ -25,5 +30,6 @@ main (void)
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{
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void (*f) (void (*)(void)) = h ();
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printf ("%p\n", f);
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+ printf ("%d\n", copyreloc);
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f (0);
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}
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--- a/gdb/testsuite/gdb.base/prelink.exp
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+++ b/gdb/testsuite/gdb.base/prelink.exp
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@@ -57,6 +57,13 @@ if {$prelink_args == ""} {
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return -1
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}
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+set test "split debug of executable"
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+if [gdb_gnu_strip_debug $binfile] {
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+ fail $test
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+} else {
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+ pass $test
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+}
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+
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if ![prelink_yes $prelink_args] {
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# Maybe we don't have prelink.
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return -1
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@@ -105,3 +112,5 @@ clean_restart $executable
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gdb_test_no_output "set verbose on"
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gdb_test "core-file $objdir/$subdir/prelink.core" "Using PIC \\(Position Independent Code\\) prelink displacement 0x\[^0\]\[0-9a-f\]* for \[^\r\n\]*[file tail ${libfile}].*" "seen displacement message"
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+
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+gdb_test "p &bssvar == bssvarp" " = 1" ".dynbss vs. .bss address shift"
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