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

["Terry Guo" <terry dot guo at arm dot com>]

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