[patch] Do not use not current line for caller-'break' [Re: Why does gdb stop at a different line than “i b ” shows while returning from function?]

[Jan Kratochvil <jan dot kratochvil at redhat dot com>]

On Sat, 04 Aug 2012 22:01:50 +0200, wempwer@gmail.com wrote:
> That's right, I didn't notice that before. Maybe it's a bug? I include the full log:

Yes, I think it is a bug.

 (gdb) up
 #1  0x00000000004005aa in main () at ./gdb.base/break-caller-line.c:29
 29       callee ();
 (gdb) PASS: gdb.base/break-caller-line.exp: up
 info line *$pc
 Line 30 of "./gdb.base/break-caller-line.c" starts at address 0x4005aa <main+9> and ends at 0x4005af <main+14>.
 (gdb) PASS: gdb.base/break-caller-line.exp: info line *$pc
 break
-Breakpoint 2 at 0x4005aa: file ./gdb.base/break-caller-line.c, line 29.
-(gdb) FAIL: gdb.base/break-caller-line.exp: break (caller line)
+Breakpoint 2 at 0x4005aa: file ./gdb.base/break-caller-line.c, line 30.
+(gdb) PASS: gdb.base/break-caller-line.exp: break

No regressions on {x86_64,x86_64-m32,i686}-fedorarawhide-linux-gnu.
For example on ia64 it is UNTESTED.


Thanks,
Jan


gdb/
2012-08-04  Jan Kratochvil  <jan.kratochvil@redhat.com>

	* breakpoint.c (parse_breakpoint_sals) <(*address) == NULL>: New
	variable pc.  Call find_pc_line instead of find_pc_overlay, restore
	original PC for it.

gdb/testsuite/
2012-08-04  Jan Kratochvil  <jan.kratochvil@redhat.com>

	* gdb.base/break-caller-line.c: New file.
	* gdb.base/break-caller-line.exp: New file.

diff --git a/gdb/breakpoint.c b/gdb/breakpoint.c
index 03719d4..3e44a5b 100644
--- a/gdb/breakpoint.c
+++ b/gdb/breakpoint.c
@@ -9128,21 +9128,27 @@ parse_breakpoint_sals (char **address,
 	{
 	  struct linespec_sals lsal;
 	  struct symtab_and_line sal;
+	  CORE_ADDR pc;
 
 	  init_sal (&sal);		/* Initialize to zeroes.  */
 	  lsal.sals.sals = (struct symtab_and_line *)
 	    xmalloc (sizeof (struct symtab_and_line));
 
 	  /* Set sal's pspace, pc, symtab, and line to the values
-	     corresponding to the last call to print_frame_info.  */
+	     corresponding to the last call to print_frame_info.
+	     Be sure to reinitialize LINE with NOTCURRENT == 0
+	     as the breakpoint line number is inappropriate otherwise.
+	     find_pc_line would adjust PC, re-set it back.  */
 	  get_last_displayed_sal (&sal);
-          sal.section = find_pc_overlay (sal.pc);
+	  pc = sal.pc;
+	  sal = find_pc_line (pc, 0);
 
 	  /* "break" without arguments is equivalent to "break *PC"
 	     where PC is the last displayed codepoint's address.  So
 	     make sure to set sal.explicit_pc to prevent GDB from
 	     trying to expand the list of sals to include all other
 	     instances with the same symtab and line.  */
+	  sal.pc = pc;
 	  sal.explicit_pc = 1;
 
 	  lsal.sals.sals[0] = sal;
diff --git a/gdb/testsuite/gdb.base/break-caller-line.c b/gdb/testsuite/gdb.base/break-caller-line.c
new file mode 100644
index 0000000..59d15ee
--- /dev/null
+++ b/gdb/testsuite/gdb.base/break-caller-line.c
@@ -0,0 +1,31 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2012 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/>.  */
+
+static int v;
+
+static void
+callee (void)
+{
+  v++;
+}
+
+int
+main (void)
+{
+  callee ();
+  return 0;
+}
diff --git a/gdb/testsuite/gdb.base/break-caller-line.exp b/gdb/testsuite/gdb.base/break-caller-line.exp
new file mode 100644
index 0000000..45abe476
--- /dev/null
+++ b/gdb/testsuite/gdb.base/break-caller-line.exp
@@ -0,0 +1,55 @@
+# Copyright (C) 2012 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/>.
+
+standard_testfile
+
+if { [prepare_for_testing ${testfile}.exp ${testfile}] } {
+    return -1
+}
+
+if ![runto callee] {
+    return 0
+}
+
+set test "up"
+gdb_test_multiple $test $test {
+    -re "\r\n(\[0-9\]+)\[ \t\]+callee \\(\\);\r\n$gdb_prompt $" {
+	set notcurrent $expect_out(1,string)
+	pass $test
+    }
+}
+
+set test {info line *$pc}
+gdb_test_multiple $test $test {
+    -re "\r\nLine (\[0-9\]+) of .*\r\n$gdb_prompt $" {
+	set current $expect_out(1,string)
+	pass $test
+    }
+}
+
+if {$notcurrent == $current} {
+    untested "target arch has an instruction after call as part of the caller line"
+    return 0
+}
+
+set test "break"
+gdb_test_multiple $test $test {
+    -re "\r\nBreakpoint \[0-9\]+ at .*, line $current\\.\r\n$gdb_prompt $" {
+	pass $test
+    }
+    -re "\r\nBreakpoint \[0-9\]+ at .*, line $notcurrent\\.\r\n$gdb_prompt $" {
+	fail "$test (caller line)"
+    }
+}