* [PATCH][gdb/testsuite] Fix gdb.opt/clobbered-registers-O2.exp with clang
@ 2022-05-24 14:07 Tom de Vries
2022-05-24 15:38 ` Luis Machado
0 siblings, 1 reply; 2+ messages in thread
From: Tom de Vries @ 2022-05-24 14:07 UTC (permalink / raw)
To: gdb-patches
Hi,
When running test-case gdb.opt/clobbered-registers-O2.exp with clang 12.0.1, I
get:
...
(gdb) run ^M
Starting program: clobbered-registers-O2 ^M
^M
Program received signal SIGSEGV, Segmentation fault.^M
gen_movsd (operand0=<optimized out>, operand1=<optimized out>) at \
clobbered-registers-O2.c:31^M
31 return *start_sequence(operand0, operand1);^M
(gdb) FAIL: gdb.opt/clobbered-registers-O2.exp: runto: run to start_sequence
...
The problem is that the breakpoint in start_sequence doesn't trigger, because:
- the call to start_sequence in gen_movsd is optimized away, despite the
__attribute__((noinline)), so the actual function start_sequence doesn't get
called, and
- the debug info doesn't contain inlined function info, so there's only one
breakpoint location.
Adding noclone and noipa alongside the noinline attribute doesn't fix this.
Adding the clang-specific attribute optnone in start_sequence does, but since
it inhibits all optimization, that's not a preferred solution in a gdb.opt
test-case, and it would work only for clang and not other compilers that
possibly have the same issue.
Fix this by moving functions start_sequence and gen_movsd into their own
files, as a way of trying harder to enforce noinline/noipa/noclone.
Tested on x86_64-linux.
Any comments?
Thanks,
- Tom
[gdb/testsuite] Fix gdb.opt/clobbered-registers-O2.exp with clang
---
gdb/testsuite/gdb.opt/clobbered-registers-O2-2.c | 24 ++++++++++++++++++++++++
gdb/testsuite/gdb.opt/clobbered-registers-O2-3.c | 22 ++++++++++++++++++++++
gdb/testsuite/gdb.opt/clobbered-registers-O2.c | 16 +---------------
gdb/testsuite/gdb.opt/clobbered-registers-O2.exp | 5 +++--
4 files changed, 50 insertions(+), 17 deletions(-)
diff --git a/gdb/testsuite/gdb.opt/clobbered-registers-O2-2.c b/gdb/testsuite/gdb.opt/clobbered-registers-O2-2.c
new file mode 100644
index 00000000000..c709c043677
--- /dev/null
+++ b/gdb/testsuite/gdb.opt/clobbered-registers-O2-2.c
@@ -0,0 +1,24 @@
+/* This file is part of GDB, the GNU debugger.
+
+ Copyright 2007-2022 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/>. */
+
+extern unsigned *start_sequence (unsigned *x, unsigned *y);
+
+unsigned
+gen_movsd (unsigned *operand0, unsigned *operand1)
+{
+ return *start_sequence (operand0, operand1);
+}
diff --git a/gdb/testsuite/gdb.opt/clobbered-registers-O2-3.c b/gdb/testsuite/gdb.opt/clobbered-registers-O2-3.c
new file mode 100644
index 00000000000..664d5f20d24
--- /dev/null
+++ b/gdb/testsuite/gdb.opt/clobbered-registers-O2-3.c
@@ -0,0 +1,22 @@
+/* This file is part of GDB, the GNU debugger.
+
+ Copyright 2007-2022 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 *
+start_sequence (unsigned *x, unsigned *y)
+{
+ return (unsigned *)0xdeadbeef;
+}
diff --git a/gdb/testsuite/gdb.opt/clobbered-registers-O2.c b/gdb/testsuite/gdb.opt/clobbered-registers-O2.c
index 83cf2267d1e..8201d99763f 100644
--- a/gdb/testsuite/gdb.opt/clobbered-registers-O2.c
+++ b/gdb/testsuite/gdb.opt/clobbered-registers-O2.c
@@ -15,21 +15,7 @@
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
-#ifndef __GNUC__
-#define __attribute__(x)
-#endif
-
-unsigned * __attribute__((noinline))
-start_sequence (unsigned * x, unsigned * y)
-{
- return (unsigned *)0xdeadbeef;
-};
-
-unsigned __attribute__((noinline))
-gen_movsd (unsigned * operand0, unsigned * operand1)
-{
- return *start_sequence(operand0, operand1);
-}
+extern unsigned gen_movsd (unsigned *operand0, unsigned *operand1);
int main(void)
{
diff --git a/gdb/testsuite/gdb.opt/clobbered-registers-O2.exp b/gdb/testsuite/gdb.opt/clobbered-registers-O2.exp
index e01f445688d..b38f3642840 100644
--- a/gdb/testsuite/gdb.opt/clobbered-registers-O2.exp
+++ b/gdb/testsuite/gdb.opt/clobbered-registers-O2.exp
@@ -18,7 +18,7 @@
# Test displaying call clobbered registers in optimized binaries.
# GDB should not show incorrect values.
-standard_testfile
+standard_testfile .c -2.c -3.c
# What compiler are we using?
#
@@ -26,7 +26,8 @@ if [get_compiler_info] {
return -1
}
-if {[prepare_for_testing "failed to prepare" $testfile $srcfile \
+if {[prepare_for_testing "failed to prepare" $testfile \
+ [list $srcfile $srcfile2 $srcfile3] \
{debug optimize=-O2 nowarnings}]} {
return -1
}
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH][gdb/testsuite] Fix gdb.opt/clobbered-registers-O2.exp with clang
2022-05-24 14:07 [PATCH][gdb/testsuite] Fix gdb.opt/clobbered-registers-O2.exp with clang Tom de Vries
@ 2022-05-24 15:38 ` Luis Machado
0 siblings, 0 replies; 2+ messages in thread
From: Luis Machado @ 2022-05-24 15:38 UTC (permalink / raw)
To: Tom de Vries, gdb-patches
On 5/24/22 15:07, Tom de Vries via Gdb-patches wrote:
> Hi,
>
> When running test-case gdb.opt/clobbered-registers-O2.exp with clang 12.0.1, I
> get:
> ...
> (gdb) run ^M
> Starting program: clobbered-registers-O2 ^M
> ^M
> Program received signal SIGSEGV, Segmentation fault.^M
> gen_movsd (operand0=<optimized out>, operand1=<optimized out>) at \
> clobbered-registers-O2.c:31^M
> 31 return *start_sequence(operand0, operand1);^M
> (gdb) FAIL: gdb.opt/clobbered-registers-O2.exp: runto: run to start_sequence
> ...
>
> The problem is that the breakpoint in start_sequence doesn't trigger, because:
> - the call to start_sequence in gen_movsd is optimized away, despite the
> __attribute__((noinline)), so the actual function start_sequence doesn't get
> called, and
> - the debug info doesn't contain inlined function info, so there's only one
> breakpoint location.
>
> Adding noclone and noipa alongside the noinline attribute doesn't fix this.
>
> Adding the clang-specific attribute optnone in start_sequence does, but since
> it inhibits all optimization, that's not a preferred solution in a gdb.opt
> test-case, and it would work only for clang and not other compilers that
> possibly have the same issue.
>
> Fix this by moving functions start_sequence and gen_movsd into their own
> files, as a way of trying harder to enforce noinline/noipa/noclone.
>
> Tested on x86_64-linux.
>
> Any comments?
>
> Thanks,
> - Tom
>
> [gdb/testsuite] Fix gdb.opt/clobbered-registers-O2.exp with clang
>
> ---
> gdb/testsuite/gdb.opt/clobbered-registers-O2-2.c | 24 ++++++++++++++++++++++++
> gdb/testsuite/gdb.opt/clobbered-registers-O2-3.c | 22 ++++++++++++++++++++++
> gdb/testsuite/gdb.opt/clobbered-registers-O2.c | 16 +---------------
> gdb/testsuite/gdb.opt/clobbered-registers-O2.exp | 5 +++--
> 4 files changed, 50 insertions(+), 17 deletions(-)
>
> diff --git a/gdb/testsuite/gdb.opt/clobbered-registers-O2-2.c b/gdb/testsuite/gdb.opt/clobbered-registers-O2-2.c
> new file mode 100644
> index 00000000000..c709c043677
> --- /dev/null
> +++ b/gdb/testsuite/gdb.opt/clobbered-registers-O2-2.c
> @@ -0,0 +1,24 @@
> +/* This file is part of GDB, the GNU debugger.
> +
> + Copyright 2007-2022 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/>. */
> +
> +extern unsigned *start_sequence (unsigned *x, unsigned *y);
> +
> +unsigned
> +gen_movsd (unsigned *operand0, unsigned *operand1)
> +{
> + return *start_sequence (operand0, operand1);
> +}
> diff --git a/gdb/testsuite/gdb.opt/clobbered-registers-O2-3.c b/gdb/testsuite/gdb.opt/clobbered-registers-O2-3.c
> new file mode 100644
> index 00000000000..664d5f20d24
> --- /dev/null
> +++ b/gdb/testsuite/gdb.opt/clobbered-registers-O2-3.c
> @@ -0,0 +1,22 @@
> +/* This file is part of GDB, the GNU debugger.
> +
> + Copyright 2007-2022 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 *
> +start_sequence (unsigned *x, unsigned *y)
> +{
> + return (unsigned *)0xdeadbeef;
> +}
> diff --git a/gdb/testsuite/gdb.opt/clobbered-registers-O2.c b/gdb/testsuite/gdb.opt/clobbered-registers-O2.c
> index 83cf2267d1e..8201d99763f 100644
> --- a/gdb/testsuite/gdb.opt/clobbered-registers-O2.c
> +++ b/gdb/testsuite/gdb.opt/clobbered-registers-O2.c
> @@ -15,21 +15,7 @@
> You should have received a copy of the GNU General Public License
> along with this program. If not, see <http://www.gnu.org/licenses/>. */
>
> -#ifndef __GNUC__
> -#define __attribute__(x)
> -#endif
> -
> -unsigned * __attribute__((noinline))
> -start_sequence (unsigned * x, unsigned * y)
> -{
> - return (unsigned *)0xdeadbeef;
> -};
> -
> -unsigned __attribute__((noinline))
> -gen_movsd (unsigned * operand0, unsigned * operand1)
> -{
> - return *start_sequence(operand0, operand1);
> -}
> +extern unsigned gen_movsd (unsigned *operand0, unsigned *operand1);
>
> int main(void)
> {
> diff --git a/gdb/testsuite/gdb.opt/clobbered-registers-O2.exp b/gdb/testsuite/gdb.opt/clobbered-registers-O2.exp
> index e01f445688d..b38f3642840 100644
> --- a/gdb/testsuite/gdb.opt/clobbered-registers-O2.exp
> +++ b/gdb/testsuite/gdb.opt/clobbered-registers-O2.exp
> @@ -18,7 +18,7 @@
> # Test displaying call clobbered registers in optimized binaries.
> # GDB should not show incorrect values.
>
> -standard_testfile
> +standard_testfile .c -2.c -3.c
>
> # What compiler are we using?
> #
> @@ -26,7 +26,8 @@ if [get_compiler_info] {
> return -1
> }
>
> -if {[prepare_for_testing "failed to prepare" $testfile $srcfile \
> +if {[prepare_for_testing "failed to prepare" $testfile \
> + [list $srcfile $srcfile2 $srcfile3] \
> {debug optimize=-O2 nowarnings}]} {
> return -1
> }
As mentioned in the other thread, this test can be a bit fragile. If the above works for clang, I'm fine with it.
Thanks for getting this addressed.
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2022-05-24 14:07 [PATCH][gdb/testsuite] Fix gdb.opt/clobbered-registers-O2.exp with clang Tom de Vries
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