205 lines
7.1 KiB
Diff
205 lines
7.1 KiB
Diff
|
http://sourceware.org/ml/gdb-patches/2010-07/msg00237.html
|
||
|
Subject: [patch] Fix regression on prelinked executables
|
||
|
|
||
|
Hi,
|
||
|
|
||
|
there is a regression since gdb-7.0 for a combination of:
|
||
|
* prelinked
|
||
|
* main executable
|
||
|
* using separate debug info
|
||
|
* using copy relocations
|
||
|
|
||
|
It is since a patch for both PIE and (AFAIK) OSX support:
|
||
|
[commit] syms_from_objfile: Relativize also MAINLINE
|
||
|
http://sourceware.org/ml/gdb-patches/2010-01/msg00080.html
|
||
|
|
||
|
which started to use problematic addr_info_make_relative even for main
|
||
|
executables. prelink<->gdb discussion at:
|
||
|
https://bugzilla.redhat.com/show_bug.cgi?id=614659
|
||
|
|
||
|
Currently in the unfortunately executables GDB has invalid displcement for
|
||
|
symbols in .bss:
|
||
|
int bssvar, *bssvarp = &bssvar;
|
||
|
(gdb) p &bssvar
|
||
|
$1 = (int *) 0x600b54
|
||
|
(gdb) p bssvarp
|
||
|
$2 = (int *) 0x600b50
|
||
|
|
||
|
<abstract-higher-point-of-view>
|
||
|
addr_info_make_relative could just simply subtract entry point address and
|
||
|
provide single CORE_ADDR objfile->offset (instead of the current
|
||
|
section_offsets array with offsets specific for each section). Linux systems
|
||
|
use always single offset for the whole objfile. AFAIK these per-section
|
||
|
offsets are there for some embedded targets. Curiously GDB already uses at
|
||
|
many places
|
||
|
baseaddr = ANOFFSET (objfile->section_offsets, SECT_OFF_TEXT (objfile));
|
||
|
instead of using offset for the appropriate section at that place and nobody
|
||
|
complains.
|
||
|
</abstract-higher-point-of-view>
|
||
|
|
||
|
No regressions on {x86_64,x86_64-m32,i686}-fedora13-linux-gnu.
|
||
|
|
||
|
Proposing for the gdb-7.2 branch. I had problems fixing up my crashing X.
|
||
|
|
||
|
|
||
|
Thanks,
|
||
|
Jan
|
||
|
|
||
|
|
||
|
gdb/
|
||
|
2010-07-15 Jan Kratochvil <jan.kratochvil@redhat.com>
|
||
|
|
||
|
* symfile.c (addr_section_name): New function.
|
||
|
(addrs_section_compar): Use it.
|
||
|
(addr_info_make_relative): Use it. Move variable sect_name into a more
|
||
|
inner block. Make ".dynbss" and ".sdynbss" checks more strict.
|
||
|
|
||
|
gdb/testsuite/
|
||
|
2010-07-15 Jan Kratochvil <jan.kratochvil@redhat.com>
|
||
|
|
||
|
* gdb.base/prelink-lib.c (copyreloc): New initialized variable.
|
||
|
* gdb.base/prelink.c (copyreloc, bssvar, bssvarp): New variables.
|
||
|
(main): Use copyreloc.
|
||
|
* gdb.base/prelink.exp (split debug of executable)
|
||
|
(.dynbss vs. .bss address shift): New tests.
|
||
|
|
||
|
Index: gdb-7.1/gdb/symfile.c
|
||
|
===================================================================
|
||
|
--- gdb-7.1.orig/gdb/symfile.c 2010-07-19 23:11:10.000000000 +0200
|
||
|
+++ gdb-7.1/gdb/symfile.c 2010-07-20 18:34:50.000000000 +0200
|
||
|
@@ -557,6 +557,23 @@ relative_addr_info_to_section_offsets (s
|
||
|
}
|
||
|
}
|
||
|
|
||
|
+/* Transform section name S for a name comparison. prelink can split section
|
||
|
+ `.bss' into two sections `.dynbss' and `.bss' (in this order). Similarly
|
||
|
+ prelink can split `.sbss' into `.sdynbss' and `.sbss'. Use virtual address
|
||
|
+ of the new `.dynbss' (`.sdynbss') section as the adjacent new `.bss'
|
||
|
+ (`.sbss') section has invalid (increased) virtual address. */
|
||
|
+
|
||
|
+static const char *
|
||
|
+addr_section_name (const char *s)
|
||
|
+{
|
||
|
+ if (strcmp (s, ".dynbss") == 0)
|
||
|
+ return ".bss";
|
||
|
+ if (strcmp (s, ".sdynbss") == 0)
|
||
|
+ return ".sbss";
|
||
|
+
|
||
|
+ return s;
|
||
|
+}
|
||
|
+
|
||
|
/* Relativize absolute addresses in ADDRS into offsets based on ABFD. Fill-in
|
||
|
also SECTINDEXes specific to ABFD there. This function can be used to
|
||
|
rebase ADDRS to start referencing different BFD than before. */
|
||
|
@@ -607,8 +624,17 @@ addr_info_make_relative (struct section_
|
||
|
if (sect && strcmp (sect_name, bfd_get_section_name (abfd, sect)) != 0)
|
||
|
sect = NULL;
|
||
|
|
||
|
- if (sect == NULL)
|
||
|
- sect = bfd_get_section_by_name (abfd, sect_name);
|
||
|
+ /* Prevent the search by name if `.bss' has the address already set from
|
||
|
+ `.dynbss'. */
|
||
|
+ if (sect == NULL
|
||
|
+ && !(0
|
||
|
+ || (strcmp (sect_name, ".bss") == 0
|
||
|
+ && i > 0
|
||
|
+ && strcmp (addrs->other[i - 1].name, ".dynbss") == 0)
|
||
|
+ || (strcmp (sect_name, ".sbss") == 0
|
||
|
+ && i > 0
|
||
|
+ && strcmp (addrs->other[i - 1].name, ".sdynbss") == 0)))
|
||
|
+ sect = bfd_get_section_by_name (abfd, addr_section_name (sect_name));
|
||
|
if (sect)
|
||
|
{
|
||
|
/* This is the index used by BFD. */
|
||
|
@@ -634,12 +660,18 @@ addr_info_make_relative (struct section_
|
||
|
a warning. Shared libraries contain just the section
|
||
|
".gnu.liblist" but it is not marked as loadable there. There is
|
||
|
no other way to identify them than by their name as the sections
|
||
|
- created by prelink have no special flags. */
|
||
|
+ created by prelink have no special flags.
|
||
|
+
|
||
|
+ For the sections `.bss' and `.sbss' see addr_section_name. */
|
||
|
|
||
|
if (!(strcmp (sect_name, ".gnu.liblist") == 0
|
||
|
|| strcmp (sect_name, ".gnu.conflict") == 0
|
||
|
- || strcmp (sect_name, ".dynbss") == 0
|
||
|
- || strcmp (sect_name, ".sdynbss") == 0))
|
||
|
+ || (strcmp (sect_name, ".bss") == 0
|
||
|
+ && i > 0
|
||
|
+ && strcmp (addrs->other[i - 1].name, ".dynbss") == 0)
|
||
|
+ || (strcmp (sect_name, ".sbss") == 0
|
||
|
+ && i > 0
|
||
|
+ && strcmp (addrs->other[i - 1].name, ".sdynbss") == 0)))
|
||
|
warning (_("section %s not found in %s"), sect_name,
|
||
|
bfd_get_filename (abfd));
|
||
|
|
||
|
Index: gdb-7.1/gdb/testsuite/gdb.base/prelink-lib.c
|
||
|
===================================================================
|
||
|
--- gdb-7.1.orig/gdb/testsuite/gdb.base/prelink-lib.c 2010-01-01 08:32:01.000000000 +0100
|
||
|
+++ gdb-7.1/gdb/testsuite/gdb.base/prelink-lib.c 2010-07-19 23:11:56.000000000 +0200
|
||
|
@@ -16,6 +16,8 @@
|
||
|
along with this program. If not, see <http://www.gnu.org/licenses/>.
|
||
|
*/
|
||
|
|
||
|
+int copyreloc = 1;
|
||
|
+
|
||
|
int
|
||
|
g (void (*p)(void))
|
||
|
{
|
||
|
Index: gdb-7.1/gdb/testsuite/gdb.base/prelink.c
|
||
|
===================================================================
|
||
|
--- gdb-7.1.orig/gdb/testsuite/gdb.base/prelink.c 2010-01-01 08:32:01.000000000 +0100
|
||
|
+++ gdb-7.1/gdb/testsuite/gdb.base/prelink.c 2010-07-19 23:11:56.000000000 +0200
|
||
|
@@ -18,6 +18,11 @@
|
||
|
|
||
|
#include <stdio.h>
|
||
|
|
||
|
+extern int copyreloc;
|
||
|
+
|
||
|
+/* Test GDB itself finds `&bssvar' right. */
|
||
|
+static int bssvar, *bssvarp = &bssvar;
|
||
|
+
|
||
|
extern void (*h (void)) (void (*)(void));
|
||
|
|
||
|
int
|
||
|
@@ -25,5 +30,6 @@ main (void)
|
||
|
{
|
||
|
void (*f) (void (*)(void)) = h ();
|
||
|
printf ("%p\n", f);
|
||
|
+ printf ("%d\n", copyreloc);
|
||
|
f (0);
|
||
|
}
|
||
|
Index: gdb-7.1/gdb/testsuite/gdb.base/prelink.exp
|
||
|
===================================================================
|
||
|
--- gdb-7.1.orig/gdb/testsuite/gdb.base/prelink.exp 2010-07-19 23:11:12.000000000 +0200
|
||
|
+++ gdb-7.1/gdb/testsuite/gdb.base/prelink.exp 2010-07-20 00:06:18.000000000 +0200
|
||
|
@@ -84,6 +84,13 @@ if { [gdb_compile "${srcdir}/${subdir}/$
|
||
|
return -1;
|
||
|
}
|
||
|
|
||
|
+set test "split debug of executable"
|
||
|
+if [gdb_gnu_strip_debug $binfile] {
|
||
|
+ fail $test
|
||
|
+} else {
|
||
|
+ pass $test
|
||
|
+}
|
||
|
+
|
||
|
set found 0
|
||
|
set coredir "${objdir}/${subdir}/coredir.[getpid]"
|
||
|
file mkdir $coredir
|
||
|
@@ -118,7 +125,7 @@ if {[catch "system \"/usr/sbin/prelink -
|
||
|
untested "${testfile}.so was not prelinked, maybe system libraries are not prelinked?"
|
||
|
return 0
|
||
|
}
|
||
|
-catch "system \"/usr/sbin/prelink -qNR --no-exec-shield ${libfile}\""
|
||
|
+catch "system \"/usr/sbin/prelink -qNR --no-exec-shield ${libfile} ${binfile}\""
|
||
|
|
||
|
# Start with a fresh gdb
|
||
|
|
||
|
@@ -131,3 +138,5 @@ gdb_load ${binfile}
|
||
|
gdb_test "set verbose on"
|
||
|
|
||
|
gdb_test "core-file $objdir/$subdir/prelink.core" {Using PIC \(Position Independent Code\) prelink displacement.*} "prelink"
|
||
|
+
|
||
|
+gdb_test "p &bssvar == bssvarp" " = 1" ".dynbss vs. .bss address shift"
|