[PATCH] Fix that different function breakpoints are set at same pc address (PR gdb/12703)

Terry Guo
2011-06-24T02:31:10Z

Hello,

This patch addresses the bug in gdb/12703 which sets two different function
breakpoints at same pc address. In this patch I enhanced the way to analyze
the ARM thumb prologue to prevent the function breakpoint from being set
outside the function body.

Patch has been tested against arm-none-eabi with no regressions. OK for
commit?

Thanks,

Terry

gdb/ChangLog:
2011-06-16 Terry Guo <terry.guo@arm.com>

PR gdb/12703
* arm-tdep.c (arm_skip_prologue): Don't scan beyond the end of
the current function.

gdb/testsuite/ChangLog:
2011-06-16 Terry Guo <terry.guo@arm.com>

PR gdb/12703
* gdb.base/break-function.c: New testcase.
* gdb.base/break-function.exp: New script.

diff --git gdb/arm-tdep.c gdb/arm-tdep.c
index 2dd8c9e..c188576 100644
--- gdb/arm-tdep.c
+++ gdb/arm-tdep.c
@@ -1372,13 +1372,13 @@ arm_skip_prologue (struct gdbarch *gdbarch,
CORE_ADDR pc)
enum bfd_endian byte_order_for_code = gdbarch_byte_order_for_code
(gdbarch);
unsigned long inst;
CORE_ADDR skip_pc;
- CORE_ADDR func_addr, limit_pc;
+ CORE_ADDR func_addr, limit_pc, end_pc;
struct symtab_and_line sal;

/* See if we can determine the end of the prologue via the symbol table.
If so, then return either PC, or the PC after the prologue, whichever
is greater. */
- if (find_pc_partial_function (pc, NULL, &func_addr, NULL))
+ if (find_pc_partial_function (pc, NULL, &func_addr, &end_pc))
{
CORE_ADDR post_prologue_pc
= skip_prologue_using_sal (gdbarch, func_addr);
@@ -1439,6 +1439,9 @@ arm_skip_prologue (struct gdbarch *gdbarch, CORE_ADDR
pc)
if (limit_pc == 0)
limit_pc = pc + 64; /* Magic. */

+ /* Don't scan beyond the end of the current function. */
+ if (limit_pc > end_pc)
+ limit_pc = end_pc;

/* Check if this is Thumb code. */
if (arm_pc_is_thumb (gdbarch, pc))
diff --git gdb/testsuite/gdb.base/break-function.c
gdb/testsuite/gdb.base/break-function.c
new file mode 100644
index 0000000..e24cf91
--- /dev/null
+++ gdb/testsuite/gdb.base/break-function.c
@@ -0,0 +1,47 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+ Copyright 1992, 1993, 1994, 1995, 1999, 2002, 2003, 2007, 2008, 2009,
2010,
+ 2011 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/>.
*/
+
+
+unsigned long _etext;
+unsigned long _data;
+unsigned long _edata;
+
+void foo(void)
+{
+ while(1)
+ {
+ }
+} /* End of function foo */
+
+void bar(void)
+{
+ unsigned long *pulSrc, *pulDest;
+
+ pulSrc = &_etext;
+ for(pulDest = &_data; pulDest < &_edata; )
+ {
+ *pulDest++ = *pulSrc++;
+ }
+}
+
+
+int main()
+{
+ bar();
+ foo();
+}
diff --git gdb/testsuite/gdb.base/break-function.exp
gdb/testsuite/gdb.base/break-function.exp
new file mode 100644
index 0000000..a42ba79
--- /dev/null
+++ gdb/testsuite/gdb.base/break-function.exp
@@ -0,0 +1,35 @@
+# Copyright 1988, 1990, 1991, 1992, 1994, 1995, 1996, 1997, 1998, 1999,
+# 2000, 2002, 2003, 2007, 2008, 2009, 2010, 2011
+# 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/>.
+
+set srcfile break-function.c
+
+if { [prepare_for_testing break-function.exp "break-function"
{break-function.c}] } {
+ return -1
+}
+
+set bp_location_boundary [gdb_get_line_number "End of function foo"]
+
+gdb_test_multiple "b foo" "Set breakpoint for function foo" {
+ -re "Breakpoint 1 at.*file.*, line (\[0-9\]+).*" {
+ set bp_pos $expect_out(1,string);
+ if { $bp_pos > $bp_location_boundary } {
+ fail "The location of function breakpoint exceeds the body of
the function.\n"
+ } else {
+ pass "PASS";
+ }
+ }
+}
--
1.7.1