[RFA/commit/testcase] "info line" should not skip prologues (was: "Re: GDB 7.4 branching status? (2011-11-23)")

Joel Brobecker
2011-11-29T03:19:44Z

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This is an issue that I discovered in your previous set of patches, but
got fixed in this iteration :-). Nonetheless, I wrote a testcase,
so I'm sending it here. I think I should commit it independenly
of your series.

I had described the problem as follow:

> The "info line" command skips function prologues, but it shouldn't.
> Consider for instance the new testcase provided with this patch.
> The code looks like this:
>
> 17
> 18 int twice (int i) { /* THIS LINE */
> 19 /* We purposefully put the return type, function prototype and
> 20 opening curly brace on the same line, in an effort to make sure
> 21 that the function prologue would be associated to that line. */
> 22 return 2 * i;
> 23 }
>
> Without this patch, GDB would report the following address range
> for line 18:
>
> (gdb) info line 18
> Line 18 of "[...]/infoline.c" is at address 0x40049b <twice+7>
> but contains no code.
>
> The indicator that the prologue was skipped comes from the fact that
> the address chosen is at twice+7, not twice+0.

--
Joel

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From c21988ba1e257d0f20f2bdaf9677b867bfa0aeb0 Mon Sep 17 00:00:00 2001
From: Joel Brobecker <brobecker@adacore.com>
Date: Fri, 25 Nov 2011 11:42:26 -0800
Subject: info line should not skip function prologues.

gdb/testsuite/ChangeLog:

* gdb.base/infoline.c, gdb.base/infoline.exp: New files.
---
gdb/testsuite/gdb.base/infoline.c | 30 ++++++++++++++++++++++++++++++
gdb/testsuite/gdb.base/infoline.exp | 30 ++++++++++++++++++++++++++++++
2 files changed, 60 insertions(+), 0 deletions(-)
create mode 100644 gdb/testsuite/gdb.base/infoline.c
create mode 100644 gdb/testsuite/gdb.base/infoline.exp

diff --git a/gdb/testsuite/gdb.base/infoline.c b/gdb/testsuite/gdb.base/infoline.c
new file mode 100644
index 0000000..7b0da2b
--- /dev/null
+++ b/gdb/testsuite/gdb.base/infoline.c
@@ -0,0 +1,30 @@
+/* Copyright 2011 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 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/>. */
+
+int twice (int i) { /* THIS LINE */
+ /* We purposefully put the return type, function prototype and
+ opening curly brace on the same line, in an effort to make sure
+ that the function prologue would be associated to that line. */
+ return 2 * i;
+}
+
+int
+main (void)
+{
+ int t = twice (1);
+ return 0;
+}
diff --git a/gdb/testsuite/gdb.base/infoline.exp b/gdb/testsuite/gdb.base/infoline.exp
new file mode 100644
index 0000000..41ff894
--- /dev/null
+++ b/gdb/testsuite/gdb.base/infoline.exp
@@ -0,0 +1,30 @@
+# Copyright (C) 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 testfile infoline
+set srcfile ${testfile}.c
+
+if { [prepare_for_testing ${testfile}.exp ${testfile}] } {
+ return -1
+}
+
+clean_restart ${testfile}
+
+# Verify that the "info line" command does not skip function prologues.
+# If it did, GDB would tell us that the line we're interested in starts
+# at <twice+N> where N is different from zero.
+set fun_decl_line [gdb_get_line_number "THIS LINE"]
+gdb_test "info line ${srcfile}:${fun_decl_line}" \
+ "Line ${fun_decl_line} of \".*${testfile}\.c\" starts at address 0x\[0-9a-f\]+ <twice> and ends at .*"
--
1.7.1