| Message ID | 20240421222657.1052635-3-thiago.bauermann@linaro.org |
|---|---|
| State | New |
| Headers | show |
| Series | Add testcase for libc memory operations | expand |
Hi, On 4/21/24 23:26, Thiago Jung Bauermann wrote: > Test behaviour of watchpoints triggered by libc's memset/memcpy/memmove. > These functions are frequently optimized with specialized instructions > that favor larger memory access operations, so make sure GDB behaves > correctly in their presence. > > There's a separate watched variable for each function so that the testcase > can test whether GDB correctly identified the watchpoint that triggered. > > Also, the watchpoint is 28 bytes away from the beginning of the buffer > being modified, so that large memory accesses (if present) are exercised. > > PR testsuite/31484 > Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=31484 > --- > gdb/testsuite/gdb.base/memops-watchpoint.c | 45 ++++++++++ > gdb/testsuite/gdb.base/memops-watchpoint.exp | 86 ++++++++++++++++++++ > 2 files changed, 131 insertions(+) > create mode 100644 gdb/testsuite/gdb.base/memops-watchpoint.c > create mode 100644 gdb/testsuite/gdb.base/memops-watchpoint.exp > > NB: As with v1, please let me know if you think there are more interesting > tests regarding watchpoint and memory accesses that can be done. I tried > to make it cover the interesting scenarios but the testcase is small, so > maybe I'm not very creative. > > Changes in v2: > - Ensure watchpoints are aligned to 4 bytes. > - Add kfail for arm-linux. > > diff --git a/gdb/testsuite/gdb.base/memops-watchpoint.c b/gdb/testsuite/gdb.base/memops-watchpoint.c > new file mode 100644 > index 000000000000..0255cfb43404 > --- /dev/null > +++ b/gdb/testsuite/gdb.base/memops-watchpoint.c > @@ -0,0 +1,45 @@ > +/* This test program is part of GDB, the GNU debugger. > + > + Copyright 2024 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/>. */ > + > +#include <stdio.h> > +#include <string.h> > + > +int > +main (void) > +{ > + /* Some targets need 4-byte alignment for hardware watchpoints. */ > + char s[40] __attribute__ ((aligned (4))) > + = "This is a relatively long string..."; > + char a[40] __attribute__ ((aligned (4))) > + = "String to be overwritten with zeroes"; > + char b[40] __attribute__ ((aligned (4))) > + = "Another string to be memcopied..."; > + char c[40] __attribute__ ((aligned (4))) > + = "Another string to be memmoved..."; > + > + /* Break here. */ > + memset (a, 0, sizeof (a)); > + > + memcpy (b, s, sizeof (b)); > + > + memmove (c, s, sizeof (c)); > + > + printf ("b = '%s'\n", b); > + printf ("c = '%s'\n", c); > + > + return 0; > +} > diff --git a/gdb/testsuite/gdb.base/memops-watchpoint.exp b/gdb/testsuite/gdb.base/memops-watchpoint.exp > new file mode 100644 > index 000000000000..0edc646e67aa > --- /dev/null > +++ b/gdb/testsuite/gdb.base/memops-watchpoint.exp > @@ -0,0 +1,86 @@ > +# Copyright 2024 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 a binary that uses standard libc memory operation functions. They are > +# frequently optimized with specialized instructions, so make sure GDB behaves > +# correctly in their presence. > + > +# It's not possible to check in which libc function the watchpoint triggers > +# without its debug info. > +require libc_has_debug_info > + > +standard_testfile > + > +set options "-fno-builtin-memset -fno-builtin-memcpy -fno-builtin-memmove" > +if { [prepare_for_testing "failed to prepare" ${testfile} ${srcfile} \ > + [list debug additional_flags=$options]] } { > + return -1 > +} > + > +set linespec ${srcfile}:[gdb_get_line_number "Break here"] > + > +if ![runto ${linespec}] { > + return > +} > + > +gdb_test "watch -location a\[28\]" \ > + "(Hardware w|W)atchpoint ${decimal}: -location a\\\[28\\\]" \ > + "set watch on a" > +gdb_test "watch -location b\[28\]" \ > + "(Hardware w|W)atchpoint ${decimal}: -location b\\\[28\\\]" \ > + "set watchpoint on b" > +gdb_test "watch -location c\[28\]" \ > + "(Hardware w|W)atchpoint ${decimal}: -location c\\\[28\\\]" \ > + "set watchpoint on c" > + > +setup_kfail breakpoints/31665 arm*-*-linux* > +gdb_test "continue" \ > + [multi_line \ > + "Continuing\\." \ > + "" \ > + "(Hardware w|W)atchpoint ${decimal}: -location a\\\[28\\\]" \ > + "" \ > + "Old value = 104 'h'" \ > + "New value = 0 '\\\\000'" \ > + ".*memset.* \\(\\) at .*:$decimal" \ > + ".*"] \ > + "continue until memset watchpoint hits" > + > +setup_kfail breakpoints/31665 arm*-*-linux* > +gdb_test "continue" \ > + [multi_line \ > + "Continuing\\." \ > + "" \ > + "(Hardware w|W)atchpoint ${decimal}: -location b\\\[28\\\]" \ > + "" \ > + "Old value = 101 'e'" \ > + "New value = 114 'r'" \ > + ".*memcpy.* \\(\\) at .*:$decimal" \ > + ".*"] \ > + "continue until memcpy watchpoint hits" > + > +# Note: Some architectures use memcpy for memmove. > +setup_kfail breakpoints/31665 arm*-*-linux* > +gdb_test "continue" \ > + [multi_line \ > + "Continuing\\." \ > + "" \ > + "(Hardware w|W)atchpoint ${decimal}: -location c\\\[28\\\]" \ > + "" \ > + "Old value = 100 'd'" \ > + "New value = 114 'r'" \ > + ".*(memmove|memcpy).* \\(\\) at .*:$decimal" \ > + ".*"] \ > + "continue until memmove watchpoint hits" For this test, on aarch64 I see full passes, but on 32-bit Arm I see 3 passes and 3 kfail's. Is that the expected outcome?
Hello Luis, Thanks for reviewing the patches! Luis Machado <luis.machado@arm.com> writes: > On 4/21/24 23:26, Thiago Jung Bauermann wrote: >> +setup_kfail breakpoints/31665 arm*-*-linux* >> +gdb_test "continue" \ >> + [multi_line \ >> + "Continuing\\." \ >> + "" \ >> + "(Hardware w|W)atchpoint ${decimal}: -location a\\\[28\\\]" \ >> + "" \ >> + "Old value = 104 'h'" \ >> + "New value = 0 '\\\\000'" \ >> + ".*memset.* \\(\\) at .*:$decimal" \ >> + ".*"] \ >> + "continue until memset watchpoint hits" >> + >> +setup_kfail breakpoints/31665 arm*-*-linux* >> +gdb_test "continue" \ >> + [multi_line \ >> + "Continuing\\." \ >> + "" \ >> + "(Hardware w|W)atchpoint ${decimal}: -location b\\\[28\\\]" \ >> + "" \ >> + "Old value = 101 'e'" \ >> + "New value = 114 'r'" \ >> + ".*memcpy.* \\(\\) at .*:$decimal" \ >> + ".*"] \ >> + "continue until memcpy watchpoint hits" >> + >> +# Note: Some architectures use memcpy for memmove. >> +setup_kfail breakpoints/31665 arm*-*-linux* >> +gdb_test "continue" \ >> + [multi_line \ >> + "Continuing\\." \ >> + "" \ >> + "(Hardware w|W)atchpoint ${decimal}: -location c\\\[28\\\]" \ >> + "" \ >> + "Old value = 100 'd'" \ >> + "New value = 114 'r'" \ >> + ".*(memmove|memcpy).* \\(\\) at .*:$decimal" \ >> + ".*"] \ >> + "continue until memmove watchpoint hits" > > For this test, on aarch64 I see full passes, but on 32-bit Arm I see > 3 passes and 3 kfail's. > > Is that the expected outcome? Yes, the testcase uncovered a bug in in hardware watchpoints with 32-bit Arm (the testcase fully passes when the testcase is modified to use software watchpoints) so I opened PR breakpoints/31665 to track it. I didn't have the chance to investigate the problem yet, but it's in my TODO list. -- Thiago
diff --git a/gdb/testsuite/gdb.base/memops-watchpoint.c b/gdb/testsuite/gdb.base/memops-watchpoint.c new file mode 100644 index 000000000000..0255cfb43404 --- /dev/null +++ b/gdb/testsuite/gdb.base/memops-watchpoint.c @@ -0,0 +1,45 @@ +/* This test program is part of GDB, the GNU debugger. + + Copyright 2024 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/>. */ + +#include <stdio.h> +#include <string.h> + +int +main (void) +{ + /* Some targets need 4-byte alignment for hardware watchpoints. */ + char s[40] __attribute__ ((aligned (4))) + = "This is a relatively long string..."; + char a[40] __attribute__ ((aligned (4))) + = "String to be overwritten with zeroes"; + char b[40] __attribute__ ((aligned (4))) + = "Another string to be memcopied..."; + char c[40] __attribute__ ((aligned (4))) + = "Another string to be memmoved..."; + + /* Break here. */ + memset (a, 0, sizeof (a)); + + memcpy (b, s, sizeof (b)); + + memmove (c, s, sizeof (c)); + + printf ("b = '%s'\n", b); + printf ("c = '%s'\n", c); + + return 0; +} diff --git a/gdb/testsuite/gdb.base/memops-watchpoint.exp b/gdb/testsuite/gdb.base/memops-watchpoint.exp new file mode 100644 index 000000000000..0edc646e67aa --- /dev/null +++ b/gdb/testsuite/gdb.base/memops-watchpoint.exp @@ -0,0 +1,86 @@ +# Copyright 2024 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 a binary that uses standard libc memory operation functions. They are +# frequently optimized with specialized instructions, so make sure GDB behaves +# correctly in their presence. + +# It's not possible to check in which libc function the watchpoint triggers +# without its debug info. +require libc_has_debug_info + +standard_testfile + +set options "-fno-builtin-memset -fno-builtin-memcpy -fno-builtin-memmove" +if { [prepare_for_testing "failed to prepare" ${testfile} ${srcfile} \ + [list debug additional_flags=$options]] } { + return -1 +} + +set linespec ${srcfile}:[gdb_get_line_number "Break here"] + +if ![runto ${linespec}] { + return +} + +gdb_test "watch -location a\[28\]" \ + "(Hardware w|W)atchpoint ${decimal}: -location a\\\[28\\\]" \ + "set watch on a" +gdb_test "watch -location b\[28\]" \ + "(Hardware w|W)atchpoint ${decimal}: -location b\\\[28\\\]" \ + "set watchpoint on b" +gdb_test "watch -location c\[28\]" \ + "(Hardware w|W)atchpoint ${decimal}: -location c\\\[28\\\]" \ + "set watchpoint on c" + +setup_kfail breakpoints/31665 arm*-*-linux* +gdb_test "continue" \ + [multi_line \ + "Continuing\\." \ + "" \ + "(Hardware w|W)atchpoint ${decimal}: -location a\\\[28\\\]" \ + "" \ + "Old value = 104 'h'" \ + "New value = 0 '\\\\000'" \ + ".*memset.* \\(\\) at .*:$decimal" \ + ".*"] \ + "continue until memset watchpoint hits" + +setup_kfail breakpoints/31665 arm*-*-linux* +gdb_test "continue" \ + [multi_line \ + "Continuing\\." \ + "" \ + "(Hardware w|W)atchpoint ${decimal}: -location b\\\[28\\\]" \ + "" \ + "Old value = 101 'e'" \ + "New value = 114 'r'" \ + ".*memcpy.* \\(\\) at .*:$decimal" \ + ".*"] \ + "continue until memcpy watchpoint hits" + +# Note: Some architectures use memcpy for memmove. +setup_kfail breakpoints/31665 arm*-*-linux* +gdb_test "continue" \ + [multi_line \ + "Continuing\\." \ + "" \ + "(Hardware w|W)atchpoint ${decimal}: -location c\\\[28\\\]" \ + "" \ + "Old value = 100 'd'" \ + "New value = 114 'r'" \ + ".*(memmove|memcpy).* \\(\\) at .*:$decimal" \ + ".*"] \ + "continue until memmove watchpoint hits"