This is the mail archive of the
gdb-patches@sourceware.org
mailing list for the GDB project.
Re: [review] Fix resolving of PC in overlapping non-zero sized functions
- From: Daniel Jacobowitz <drow at false dot org>
- To: Jan Kratochvil <jan dot kratochvil at redhat dot com>
- Cc: gdb-patches at sourceware dot org
- Date: Tue, 9 Jan 2007 17:14:44 -0500
- Subject: Re: [review] Fix resolving of PC in overlapping non-zero sized functions
- References: <20061030124816.GA20298@host0.dyn.jankratochvil.net>
Sorry for not getting back to this one sooner. I definitely broke
this case when I rewrote lookup_minimal_symbol_by_pc_section; thanks
for fixing it.
On Mon, Oct 30, 2006 at 01:48:16PM +0100, Jan Kratochvil wrote:
> 2006-10-30 Jan Kratochvil <jan.kratochvil@redhat.com>
>
> * gdb/minsyms.c (lookup_minimal_symbol_by_pc_section): Handle
> overlapping non-zero sized functions (for glibc `__nanosleep').
>
> 2006-10-30 Jan Kratochvil <jan.kratochvil@redhat.com>
>
> * gdb.arch/i386-size-overlap.c, gdb.arch/i386-size-overlap.exp: New
> file, provide nested (overlapping) functions for the PC resolving.
The patch and testcase look fine. I adjusted the comments and
changelog entries, and checked in this copy. Briefer comments have
a better chance of staying accurate as the code changes, and it's
easy enough to find the submission on the mailing list later.
--
Daniel Jacobowitz
CodeSourcery
2007-01-09 Jan Kratochvil <jan.kratochvil@redhat.com>
* minsyms.c (lookup_minimal_symbol_by_pc_section): Handle
nested symbols.
2007-01-09 Jan Kratochvil <jan.kratochvil@redhat.com>
* gdb.arch/i386-size-overlap.c, gdb.arch/i386-size-overlap.exp: New.
Index: minsyms.c
===================================================================
RCS file: /cvs/src/src/gdb/minsyms.c,v
retrieving revision 1.48
diff -u -p -r1.48 minsyms.c
--- minsyms.c 9 Jan 2007 17:58:52 -0000 1.48
+++ minsyms.c 9 Jan 2007 22:10:48 -0000
@@ -510,6 +510,22 @@ lookup_minimal_symbol_by_pc_section (COR
continue;
}
+ /* If we are past the end of the current symbol, try
+ the previous symbol if it has a larger overlapping
+ size. This happens on i686-pc-linux-gnu with glibc;
+ the nocancel variants of system calls are inside
+ the cancellable variants, but both have sizes. */
+ if (hi > 0
+ && MSYMBOL_SIZE (&msymbol[hi]) != 0
+ && pc >= (SYMBOL_VALUE_ADDRESS (&msymbol[hi])
+ + MSYMBOL_SIZE (&msymbol[hi]))
+ && pc < (SYMBOL_VALUE_ADDRESS (&msymbol[hi - 1])
+ + MSYMBOL_SIZE (&msymbol[hi - 1])))
+ {
+ hi--;
+ continue;
+ }
+
/* Otherwise, this symbol must be as good as we're going
to get. */
break;
Index: testsuite/gdb.arch/i386-size-overlap.c
===================================================================
RCS file: testsuite/gdb.arch/i386-size-overlap.c
diff -N testsuite/gdb.arch/i386-size-overlap.c
--- /dev/null 1 Jan 1970 00:00:00 -0000
+++ testsuite/gdb.arch/i386-size-overlap.c 9 Jan 2007 22:10:48 -0000
@@ -0,0 +1,53 @@
+/* Overlapping symbol sizes test program.
+
+ Copyright 2007 Free Software Foundation, Inc.
+
+ This file is part of GDB.
+
+ 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 2 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, write to the Free Software
+ Foundation, Inc., 59 Temple Place - Suite 330,
+ Boston, MA 02111-1307, USA. */
+
+#ifdef SYMBOL_PREFIX
+#define SYMBOL(str) SYMBOL_PREFIX #str
+#else
+#define SYMBOL(str) #str
+#endif
+
+void
+trap (void)
+{
+ asm ("int $0x03");
+}
+
+/* Jump from a function with its symbol size set, to a function
+ named by a local label. GDB should report the `main' function
+ even for the rest, after the global `inner' ends. */
+
+asm(".text\n"
+ " .align 8\n"
+ " .globl " SYMBOL (main) "\n"
+ SYMBOL (main) ":\n"
+ " pushl %ebp\n"
+ " mov %esp, %ebp\n"
+ " call .Lfunc\n"
+ " ret\n"
+ SYMBOL (inner) ":\n"
+ " ret\n"
+ " .size " SYMBOL (inner) ", .-" SYMBOL (inner) "\n"
+ ".Lfunc:\n"
+ " pushl %ebp\n"
+ " mov %esp, %ebp\n"
+ " call " SYMBOL (trap) "\n"
+ " .size " SYMBOL (main) ", .-" SYMBOL (main) "\n");
Index: testsuite/gdb.arch/i386-size-overlap.exp
===================================================================
RCS file: testsuite/gdb.arch/i386-size-overlap.exp
diff -N testsuite/gdb.arch/i386-size-overlap.exp
--- /dev/null 1 Jan 1970 00:00:00 -0000
+++ testsuite/gdb.arch/i386-size-overlap.exp 9 Jan 2007 22:10:48 -0000
@@ -0,0 +1,76 @@
+# Copyright 2007 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 2 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, write to the Free Software
+# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+
+# This file is part of the gdb testsuite.
+
+if $tracelevel {
+ strace $tracelevel
+}
+
+# Test that GDB can handle overlapping sizes of symbols.
+
+if ![istarget "i?86-*-*"] then {
+ verbose "Skipping i386 unwinder tests."
+ return
+}
+
+set testfile "i386-size-overlap"
+set srcfile ${testfile}.c
+set binfile ${objdir}/${subdir}/${testfile}
+
+# some targets have leading underscores on assembly symbols.
+# TODO: detect this automatically
+set additional_flags ""
+if [istarget "i?86-*-cygwin*"] then {
+ set additional_flags "additional_flags=-DSYMBOL_PREFIX=\"_\""
+}
+
+if { [gdb_compile "${srcdir}/${subdir}/${srcfile}" "${binfile}" \
+ executable [list debug $additional_flags]] != "" } {
+ untested "i386-size"
+ return -1
+}
+
+gdb_exit
+gdb_start
+gdb_reinitialize_dir $srcdir/$subdir
+gdb_load ${binfile}
+
+# We use gdb_run_cmd so this stands a chance to work for remote
+# targets too.
+gdb_run_cmd
+
+gdb_expect {
+ -re "Program received signal SIGTRAP.*$gdb_prompt $" {
+ pass "run past main"
+ }
+ -re ".*$gdb_prompt $" {
+ fail "run past main"
+ }
+ timeout {
+ fail "run past main (timeout)"
+ }
+}
+
+set message "backtrace shows the outer function"
+gdb_test_multiple "backtrace 10" $message {
+ -re "#1\[ \t]*$hex in inner.*$gdb_prompt $" {
+ fail $message
+ }
+ -re "#1\[ \t]*$hex in main.*$gdb_prompt $" {
+ pass $message
+ }
+}