Fix language of compilation unit with unknown file extension (Re: [PATCH] Guard compile tests from running when unsupported + harden feature support check)
Commit Message
On 08/19/2015 08:57 PM, Pedro Alves wrote:
> On 08/19/2015 07:01 PM, Luis Machado wrote:
>> It could be either a GDB bug for not honoring the language in the DIE
>> itself or a testcase issue for not naming the source file with the
>> correct language extension.
>
> I think it's a GDB bug. See patch below.
I had left some unnecessary bits in the test's assembly (copy/paste, and
then insufficient trimming). Here's a leaner version.
---
From 8451d7202d4126bfaec5a49fe555989b6fd9b2b1 Mon Sep 17 00:00:00 2001
From: Pedro Alves <palves@redhat.com>
Date: Wed, 19 Aug 2015 20:52:44 +0100
Subject: [PATCH] Fix language of compilation unit with unknown file extension
Here, in dwarfread.c:process_full_comp_unit:
/* Set symtab language to language from DW_AT_language. If the
compilation is from a C file generated by language preprocessors, do
not set the language if it was already deduced by start_subfile. */
if (!(cu->language == language_c
&& COMPUNIT_FILETABS (cust)->language != language_c))
COMPUNIT_FILETABS (cust)->language = cu->language;
in case start_subfile doesn't manage to deduce a language
COMPUNIT_FILETABS(cust)->language ends up as language_unknown, not
language_c. So the condition above evals false and we never set the
language from the cu's language.
gdb/ChangeLog:
2015-08-19 Pedro Alves <palves@redhat.com>
* dwarf2read.c (process_full_comp_unit): To tell whether
start_subfile managed to deduce a language, test for
language_unknown instead of language_c.
gdb/testsuite/ChangeLog:
2015-08-19 Pedro Alves <palves@redhat.com>
* gdb.dwarf2/comp-unit-lang.exp: New file.
* gdb.dwarf2/comp-unit-lang.c: New file.
---
gdb/dwarf2read.c | 2 +-
gdb/testsuite/gdb.dwarf2/comp-unit-lang.c | 34 ++++++++++++
gdb/testsuite/gdb.dwarf2/comp-unit-lang.exp | 83 +++++++++++++++++++++++++++++
3 files changed, 118 insertions(+), 1 deletion(-)
create mode 100644 gdb/testsuite/gdb.dwarf2/comp-unit-lang.c
create mode 100644 gdb/testsuite/gdb.dwarf2/comp-unit-lang.exp
Comments
On Wed, Aug 19, 2015 at 1:02 PM, Pedro Alves <palves@redhat.com> wrote:
> On 08/19/2015 08:57 PM, Pedro Alves wrote:
>> On 08/19/2015 07:01 PM, Luis Machado wrote:
>>> It could be either a GDB bug for not honoring the language in the DIE
>>> itself or a testcase issue for not naming the source file with the
>>> correct language extension.
>>
>> I think it's a GDB bug. See patch below.
>
> I had left some unnecessary bits in the test's assembly (copy/paste, and
> then insufficient trimming). Here's a leaner version.
>
> ---
> From 8451d7202d4126bfaec5a49fe555989b6fd9b2b1 Mon Sep 17 00:00:00 2001
> From: Pedro Alves <palves@redhat.com>
> Date: Wed, 19 Aug 2015 20:52:44 +0100
> Subject: [PATCH] Fix language of compilation unit with unknown file extension
>
> Here, in dwarfread.c:process_full_comp_unit:
>
> /* Set symtab language to language from DW_AT_language. If the
> compilation is from a C file generated by language preprocessors, do
> not set the language if it was already deduced by start_subfile. */
> if (!(cu->language == language_c
> && COMPUNIT_FILETABS (cust)->language != language_c))
> COMPUNIT_FILETABS (cust)->language = cu->language;
>
> in case start_subfile doesn't manage to deduce a language
> COMPUNIT_FILETABS(cust)->language ends up as language_unknown, not
> language_c. So the condition above evals false and we never set the
> language from the cu's language.
>
> gdb/ChangeLog:
> 2015-08-19 Pedro Alves <palves@redhat.com>
>
> * dwarf2read.c (process_full_comp_unit): To tell whether
> start_subfile managed to deduce a language, test for
> language_unknown instead of language_c.
>
> gdb/testsuite/ChangeLog:
> 2015-08-19 Pedro Alves <palves@redhat.com>
>
> * gdb.dwarf2/comp-unit-lang.exp: New file.
> * gdb.dwarf2/comp-unit-lang.c: New file.
LGTM.
I'm assuming the "global lang" in the test is necessary.
Didn't verify it though.
@@ -8079,7 +8079,7 @@ process_full_comp_unit (struct dwarf2_per_cu_data *per_cu,
compilation is from a C file generated by language preprocessors, do
not set the language if it was already deduced by start_subfile. */
if (!(cu->language == language_c
- && COMPUNIT_FILETABS (cust)->language != language_c))
+ && COMPUNIT_FILETABS (cust)->language != language_unknown))
COMPUNIT_FILETABS (cust)->language = cu->language;
/* GCC-4.0 has started to support -fvar-tracking. GCC-3.x still can
new file mode 100644
@@ -0,0 +1,34 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+ Copyright 2011-2015 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/>. */
+
+asm (".section \".text\"");
+asm (".balign 8");
+asm ("func_start: .globl func_start");
+
+static void
+func (void)
+{
+}
+
+asm ("func_end: .globl func_end");
+
+int
+main (void)
+{
+ func ();
+ return 0;
+}
new file mode 100644
@@ -0,0 +1,83 @@
+# Copyright 2014-2015 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/>.
+
+# Test that GDB determines the frame's language based on the comp
+# unit's language, even if the file has an unknown file extension,
+# such as ".txt".
+
+load_lib dwarf.exp
+
+# This test can only be run on targets which support DWARF-2 and use
+# gas.
+if {![dwarf2_support]} {
+ return 0
+}
+
+standard_testfile .c comp-unit-lang.S
+
+# Assemble the DWARF using CU_LANG as compilation unit's language.
+# Run to a function in that compilation unit and check that GDB
+# figures out that the language is GDB_LANG.
+
+proc do_test {cu_lang gdb_lang} {
+ global testfile srcfile srcfile2
+
+ global lang
+ set lang $cu_lang
+
+ # Make some DWARF for the test.
+ set asm_file [standard_output_file $srcfile2]
+ Dwarf::assemble $asm_file {
+ # Creating a CU with 4-byte addresses lets this test link on
+ # both 32- and 64-bit machines.
+ cu { addr_size 4 } {
+ extern func_start func_end
+
+ global lang
+
+ compile_unit {
+ {name file1.txt}
+ {language @$lang}
+ {low_pc func_start addr}
+ {high_pc func_end addr}
+ } {
+ subprogram {
+ {external 1 flag}
+ {name func}
+ {low_pc func_start addr}
+ {high_pc func_end addr}
+ } {
+ }
+ }
+ }
+ }
+
+ if { [prepare_for_testing "failed to prepare" ${testfile} \
+ [list $srcfile $asm_file] {nodebug}] } {
+ return -1
+ }
+
+ if ![runto func] {
+ return -1
+ }
+
+ gdb_test "show language" "\"auto; currently $gdb_lang\".*"
+}
+
+# Some paths in the debugger that built-in fallbacks to C. Check C++
+# as well to make sure the test doesn't happen to work because of such
+# a fallback.
+do_test DW_LANG_C "c"
+do_test DW_LANG_C_plus_plus "c\\+\\+"