* [PATCH] [gdb/symtab] Add optimized out static var to cooked index
@ 2023-07-20 14:40 Tom de Vries
2023-07-20 15:58 ` [PATCH, v2] " Tom de Vries
2023-07-20 21:05 ` [PATCH] " Tom Tromey
0 siblings, 2 replies; 3+ messages in thread
From: Tom de Vries @ 2023-07-20 14:40 UTC (permalink / raw)
To: gdb-patches; +Cc: Tom Tromey
Consider the test-case:
...
$ cat main.c
int main (void) { return 0; }
$ cat static-optimized-out.c
static int aaa;
...
compiled like this:
...
$ gcc-12 static-optimized-out.c main.c -g -O2 -flto
...
There's a difference in behaviour depending on symtab expansion state:
...
$ gdb -q -batch a.out -ex "print aaa"
No symbol "aaa" in current context.
$ gdb -q -batch a.out -ex "maint expand-symtab" -ex "print aaa"
$1 = <optimized out>
...
The reason for the difference is that the optimized out variable aaa:
...
<1><104>: Abbrev Number: 2 (DW_TAG_variable)
<105> DW_AT_name : aaa
<109> DW_AT_decl_file : 1
<10a> DW_AT_decl_line : 18
<10b> DW_AT_decl_column : 12
<10c> DW_AT_type : <0x110>
...
is not added to the cooked index because of this clause in abbrev_table::read:
...
else if (!has_location && !has_specification_or_origin && !has_external
&& cur_abbrev->tag == DW_TAG_variable)
cur_abbrev->interesting = false;
...
Fix this inconsistency by making sure that the optimized out variable is added
to the cooked index.
Regression tested on x86_64-linux.
Tested the C test-case with gcc-8 to gcc-12, for which we consistently get:
...
(gdb) print aaa^M
$1 = <optimized out>^M
...
and with gcc 7.5.0 and clang 13.0.1, for which we consistently get:
...
(gdb) print aaa^M
No symbol "aaa" in current context.^M
...
due to missing debug info for the variable.
PR symtab/30656
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=30656
---
gdb/dwarf2/abbrev.c | 9 ----
gdb/testsuite/gdb.opt/main.c | 22 +++++++++
gdb/testsuite/gdb.opt/static-optimized-out.c | 18 +++++++
.../gdb.opt/static-optimized-out.exp | 49 +++++++++++++++++++
4 files changed, 89 insertions(+), 9 deletions(-)
create mode 100644 gdb/testsuite/gdb.opt/main.c
create mode 100644 gdb/testsuite/gdb.opt/static-optimized-out.c
create mode 100644 gdb/testsuite/gdb.opt/static-optimized-out.exp
diff --git a/gdb/dwarf2/abbrev.c b/gdb/dwarf2/abbrev.c
index 1ebf8f6eed5..3a429fd41b1 100644
--- a/gdb/dwarf2/abbrev.c
+++ b/gdb/dwarf2/abbrev.c
@@ -162,7 +162,6 @@ abbrev_table::read (struct dwarf2_section_info *section,
bool has_specification_or_origin = false;
bool has_name = false;
bool has_linkage_name = false;
- bool has_location = false;
bool has_external = false;
/* Now read in declarations. */
@@ -217,11 +216,6 @@ abbrev_table::read (struct dwarf2_section_info *section,
has_linkage_name = true;
break;
- case DW_AT_const_value:
- case DW_AT_location:
- has_location = true;
- break;
-
case DW_AT_sibling:
if (is_csize && cur_attr.form == DW_FORM_ref4)
sibling_offset = size;
@@ -296,9 +290,6 @@ abbrev_table::read (struct dwarf2_section_info *section,
cur_abbrev->interesting = false;
else if (!tag_interesting_for_index (cur_abbrev->tag))
cur_abbrev->interesting = false;
- else if (!has_location && !has_specification_or_origin && !has_external
- && cur_abbrev->tag == DW_TAG_variable)
- cur_abbrev->interesting = false;
else
cur_abbrev->interesting = true;
diff --git a/gdb/testsuite/gdb.opt/main.c b/gdb/testsuite/gdb.opt/main.c
new file mode 100644
index 00000000000..c6beff77dbe
--- /dev/null
+++ b/gdb/testsuite/gdb.opt/main.c
@@ -0,0 +1,22 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+ Copyright 2023 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/>. */
+
+int
+main (void)
+{
+ return 0;
+}
diff --git a/gdb/testsuite/gdb.opt/static-optimized-out.c b/gdb/testsuite/gdb.opt/static-optimized-out.c
new file mode 100644
index 00000000000..44287fbd6d2
--- /dev/null
+++ b/gdb/testsuite/gdb.opt/static-optimized-out.c
@@ -0,0 +1,18 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+ Copyright 2023 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 aaa;
diff --git a/gdb/testsuite/gdb.opt/static-optimized-out.exp b/gdb/testsuite/gdb.opt/static-optimized-out.exp
new file mode 100644
index 00000000000..262485a5bda
--- /dev/null
+++ b/gdb/testsuite/gdb.opt/static-optimized-out.exp
@@ -0,0 +1,49 @@
+# Copyright 2023 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/>.
+
+# Check that an optimized out static variable is printed the same independent
+# of state of symtab expansion.
+
+standard_testfile .c main.c
+
+set opts {}
+lappend opts debug
+lappend opts "optimize=-O2 -flto"
+
+if { [prepare_for_testing "failed to prepare" $testfile \
+ [list $srcfile $srcfile2] $opts] } {
+ return -1
+}
+
+set val ""
+gdb_test_multiple "print aaa" "" {
+ -re -wrap "^(?:\\$$decimal = )?(.*)" {
+ set val $expect_out(1,string)
+ }
+}
+
+if { $val == "" } {
+ return
+}
+
+# Expand all symbol tables.
+gdb_test_no_output "maint expand-symtab"
+
+# Make sure we do an actual lookup rather than just returning the same as
+# before.
+gdb_test "maint flush symbol-cache"
+
+# Now check that we get the same result in both cases.
+gdb_test "print aaa" [string_to_regexp $val] "consistency"
base-commit: 22e69d8d37738c2aa33543b9f311130d3fe2e4c3
--
2.35.3
^ permalink raw reply [flat|nested] 3+ messages in thread
* [PATCH, v2] [gdb/symtab] Add optimized out static var to cooked index
2023-07-20 14:40 [PATCH] [gdb/symtab] Add optimized out static var to cooked index Tom de Vries
@ 2023-07-20 15:58 ` Tom de Vries
2023-07-20 21:05 ` [PATCH] " Tom Tromey
1 sibling, 0 replies; 3+ messages in thread
From: Tom de Vries @ 2023-07-20 15:58 UTC (permalink / raw)
To: gdb-patches; +Cc: Tom Tromey
[-- Attachment #1: Type: text/plain, Size: 265 bytes --]
On 7/20/23 16:40, Tom de Vries via Gdb-patches wrote:
And here's a v2:
- add a dwarf assembly test-case (that I already had partially written,
but forgotten about)
- fix a few nits in the gdb.opt testcase (gdb_test -> gdb_test_no_output
etc)
Thanks,
- Tom
[-- Attachment #2: v2-0001-gdb-symtab-Add-optimized-out-static-var-to-cooked.patch --]
[-- Type: text/x-patch, Size: 9823 bytes --]
From 120e45112c2fe56f5ba1bed34c904bff53df9bde Mon Sep 17 00:00:00 2001
From: Tom de Vries <tdevries@suse.de>
Date: Thu, 20 Jul 2023 13:28:44 +0200
Subject: [PATCH v2] [gdb/symtab] Add optimized out static var to cooked index
Consider the test-case:
...
$ cat main.c
int main (void) { return 0; }
$ cat static-optimized-out.c
static int aaa;
...
compiled like this:
...
$ gcc-12 static-optimized-out.c main.c -g -O2 -flto
...
There's a difference in behaviour depending on symtab expansion state:
...
$ gdb -q -batch a.out -ex "print aaa"
No symbol "aaa" in current context.
$ gdb -q -batch a.out -ex "maint expand-symtab" -ex "print aaa"
$1 = <optimized out>
...
The reason for the difference is that the optimized out variable aaa:
...
<1><104>: Abbrev Number: 2 (DW_TAG_variable)
<105> DW_AT_name : aaa
<109> DW_AT_decl_file : 1
<10a> DW_AT_decl_line : 18
<10b> DW_AT_decl_column : 12
<10c> DW_AT_type : <0x110>
...
is not added to the cooked index because of this clause in abbrev_table::read:
...
else if (!has_location && !has_specification_or_origin && !has_external
&& cur_abbrev->tag == DW_TAG_variable)
cur_abbrev->interesting = false;
...
Fix this inconsistency by making sure that the optimized out variable is added
to the cooked index.
Regression tested on x86_64-linux.
Add two test-cases, a C test-case gdb.opt/static-optimized-out.exp and a dwarf
assembly test-case gdb.dwarf2/static-optimized-out.exp.
Tested gdb.opt/static-optimized-out.exp with gcc-8 to gcc-12, for which we now
consistently get:
...
(gdb) print aaa^M
$1 = <optimized out>^M
...
and with gcc 7.5.0 and clang 13.0.1, for which we still consistently get:
...
(gdb) print aaa^M
No symbol "aaa" in current context.^M
...
due to missing debug info for the variable.
PR symtab/30656
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=30656
---
gdb/dwarf2/abbrev.c | 9 ---
.../gdb.dwarf2/static-optimized-out.exp | 67 +++++++++++++++++++
gdb/testsuite/gdb.opt/main.c | 22 ++++++
gdb/testsuite/gdb.opt/static-optimized-out.c | 18 +++++
.../gdb.opt/static-optimized-out.exp | 49 ++++++++++++++
5 files changed, 156 insertions(+), 9 deletions(-)
create mode 100644 gdb/testsuite/gdb.dwarf2/static-optimized-out.exp
create mode 100644 gdb/testsuite/gdb.opt/main.c
create mode 100644 gdb/testsuite/gdb.opt/static-optimized-out.c
create mode 100644 gdb/testsuite/gdb.opt/static-optimized-out.exp
diff --git a/gdb/dwarf2/abbrev.c b/gdb/dwarf2/abbrev.c
index 1ebf8f6eed5..3a429fd41b1 100644
--- a/gdb/dwarf2/abbrev.c
+++ b/gdb/dwarf2/abbrev.c
@@ -162,7 +162,6 @@ abbrev_table::read (struct dwarf2_section_info *section,
bool has_specification_or_origin = false;
bool has_name = false;
bool has_linkage_name = false;
- bool has_location = false;
bool has_external = false;
/* Now read in declarations. */
@@ -217,11 +216,6 @@ abbrev_table::read (struct dwarf2_section_info *section,
has_linkage_name = true;
break;
- case DW_AT_const_value:
- case DW_AT_location:
- has_location = true;
- break;
-
case DW_AT_sibling:
if (is_csize && cur_attr.form == DW_FORM_ref4)
sibling_offset = size;
@@ -296,9 +290,6 @@ abbrev_table::read (struct dwarf2_section_info *section,
cur_abbrev->interesting = false;
else if (!tag_interesting_for_index (cur_abbrev->tag))
cur_abbrev->interesting = false;
- else if (!has_location && !has_specification_or_origin && !has_external
- && cur_abbrev->tag == DW_TAG_variable)
- cur_abbrev->interesting = false;
else
cur_abbrev->interesting = true;
diff --git a/gdb/testsuite/gdb.dwarf2/static-optimized-out.exp b/gdb/testsuite/gdb.dwarf2/static-optimized-out.exp
new file mode 100644
index 00000000000..f3eff586911
--- /dev/null
+++ b/gdb/testsuite/gdb.dwarf2/static-optimized-out.exp
@@ -0,0 +1,67 @@
+# Copyright 2023 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/>.
+
+# Check that an optimized out static variable is printed the same independent
+# of state of symtab expansion. See also gdb.opt/static-optimized-out.exp.
+
+load_lib dwarf.exp
+
+# This test can only be run on targets which support DWARF-2 and use gas.
+require dwarf2_support
+
+standard_testfile main.c -dw.S
+
+# Make DWARF for the test.
+set asm_file [standard_output_file $srcfile2]
+Dwarf::assemble $asm_file {
+ cu {} {
+ compile_unit {
+ {
+ language @DW_LANG_C
+ }
+ } {
+ declare_labels integer_label
+
+ integer_label: DW_TAG_base_type {
+ {DW_AT_byte_size 4 DW_FORM_sdata}
+ {DW_AT_encoding @DW_ATE_signed}
+ {DW_AT_name integer}
+ }
+
+ DW_TAG_variable {
+ {name var}
+ {type :$integer_label}
+ }
+ }
+ }
+}
+
+if { [prepare_for_testing "failed to prepare" ${testfile} \
+ [list $srcfile $asm_file] {nodebug}] } {
+ return -1
+}
+
+gdb_test "print var" " = <optimized out>"
+
+# Expand all symbol tables.
+gdb_test_no_output "maint expand-symtabs"
+
+# Make sure we do an actual lookup rather than just returning the same as
+# before.
+gdb_test_no_output "maint flush symbol-cache"
+
+with_test_prefix "after expand-symtabs" {
+ gdb_test "print var" " = <optimized out>"
+}
diff --git a/gdb/testsuite/gdb.opt/main.c b/gdb/testsuite/gdb.opt/main.c
new file mode 100644
index 00000000000..c6beff77dbe
--- /dev/null
+++ b/gdb/testsuite/gdb.opt/main.c
@@ -0,0 +1,22 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+ Copyright 2023 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/>. */
+
+int
+main (void)
+{
+ return 0;
+}
diff --git a/gdb/testsuite/gdb.opt/static-optimized-out.c b/gdb/testsuite/gdb.opt/static-optimized-out.c
new file mode 100644
index 00000000000..44287fbd6d2
--- /dev/null
+++ b/gdb/testsuite/gdb.opt/static-optimized-out.c
@@ -0,0 +1,18 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+ Copyright 2023 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 aaa;
diff --git a/gdb/testsuite/gdb.opt/static-optimized-out.exp b/gdb/testsuite/gdb.opt/static-optimized-out.exp
new file mode 100644
index 00000000000..bd673b6503e
--- /dev/null
+++ b/gdb/testsuite/gdb.opt/static-optimized-out.exp
@@ -0,0 +1,49 @@
+# Copyright 2023 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/>.
+
+# Check that an optimized out static variable is printed the same independent
+# of state of symtab expansion. See also gdb.dwarf2/static-optimized-out.exp.
+
+standard_testfile .c main.c
+
+set opts {}
+lappend opts debug
+lappend opts "optimize=-O2 -flto"
+
+if { [prepare_for_testing "failed to prepare" $testfile \
+ [list $srcfile $srcfile2] $opts] } {
+ return -1
+}
+
+set val ""
+gdb_test_multiple "print aaa" "" {
+ -re -wrap "^(?:\\$$decimal = )?(.*)" {
+ set val $expect_out(1,string)
+ }
+}
+
+if { $val == "" } {
+ return
+}
+
+# Expand all symbol tables.
+gdb_test_no_output "maint expand-symtab"
+
+# Make sure we do an actual lookup rather than just returning the same as
+# before.
+gdb_test_no_output "maint flush symbol-cache"
+
+# Now check that we get the same result in both cases.
+gdb_test "print aaa" [string_to_regexp $val] "consistency"
base-commit: 22e69d8d37738c2aa33543b9f311130d3fe2e4c3
--
2.35.3
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] [gdb/symtab] Add optimized out static var to cooked index
2023-07-20 14:40 [PATCH] [gdb/symtab] Add optimized out static var to cooked index Tom de Vries
2023-07-20 15:58 ` [PATCH, v2] " Tom de Vries
@ 2023-07-20 21:05 ` Tom Tromey
1 sibling, 0 replies; 3+ messages in thread
From: Tom Tromey @ 2023-07-20 21:05 UTC (permalink / raw)
To: Tom de Vries; +Cc: gdb-patches, Tom Tromey
>>>>> "Tom" == Tom de Vries <tdevries@suse.de> writes:
Tom> Tested the C test-case with gcc-8 to gcc-12, for which we consistently get:
Tom> ...
Tom> (gdb) print aaa^M
Tom> $1 = <optimized out>^M
Tom> ...
The patch is ok. Thanks.
Tom
^ permalink raw reply [flat|nested] 3+ messages in thread
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