[PATCH v2 3/5] gdb/testsuite: Add gdb.arch/aarch64-mops-watchpoint.exp

[Thiago Jung Bauermann <thiago.bauermann@linaro.org>]

Test behaviour of watchpoints triggered by MOPS instructions.  This test
is similar to gdb.base/memops-watchpoint.exp, but specifically for MOPS
instructions rather than whatever instructions are used in the libc's
implementation of memset/memcpy/memmove.

There's a separate watched variable for each set of instructions so that
the testcase can test whether GDB correctly identified the watchpoint
that triggered in each case.
---
 .../gdb.arch/aarch64-mops-watchpoint.c        | 66 ++++++++++++++++
 .../gdb.arch/aarch64-mops-watchpoint.exp      | 79 +++++++++++++++++++
 gdb/testsuite/lib/gdb.exp                     | 61 ++++++++++++++
 3 files changed, 206 insertions(+)
 create mode 100644 gdb/testsuite/gdb.arch/aarch64-mops-watchpoint.c
 create mode 100644 gdb/testsuite/gdb.arch/aarch64-mops-watchpoint.exp

No change in v2.

diff --git a/gdb/testsuite/gdb.arch/aarch64-mops-watchpoint.c b/gdb/testsuite/gdb.arch/aarch64-mops-watchpoint.c
new file mode 100644
index 000000000000..b981f033d210
--- /dev/null
+++ b/gdb/testsuite/gdb.arch/aarch64-mops-watchpoint.c
@@ -0,0 +1,66 @@
+/* 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/>.  */
+
+int
+main (void)
+{
+  char source[40] __attribute__ ((aligned (8)))
+    = "This is a relatively long string...";
+  char a[40] __attribute__ ((aligned (8)))
+    = "String to be overwritten with zeroes";
+  char b[40] __attribute__ ((aligned (8)))
+    = "Another string to be memcopied...";
+  char c[40] __attribute__ ((aligned (8)))
+    = "Another string to be memmoved...";
+  char *p, *q;
+  long size, zero;
+
+  /* Break here.  */
+  p = a;
+  size = sizeof (a);
+  zero = 0;
+  /* memset implemented in MOPS instructions.  */
+  __asm__ volatile ("setp [%0]!, %1!, %2\n\t"
+		    "setm [%0]!, %1!, %2\n\t"
+		    "sete [%0]!, %1!, %2\n\t"
+		    : "+&r"(p), "+&r"(size)
+		    : "r"(zero)
+		    : "memory");
+
+  p = b;
+  q = source;
+  size = sizeof (b);
+  /* memmove implemented in MOPS instructions.  */
+  __asm__ volatile ("cpyp   [%0]!, [%1]!, %2!\n\t"
+		    "cpym   [%0]!, [%1]!, %2!\n\t"
+		    "cpye   [%0]!, [%1]!, %2!\n\t"
+		    : "+&r" (p), "+&r" (q), "+&r" (size)
+		    :
+		    : "memory");
+  p = c;
+  q = source;
+  size = sizeof (c);
+  /* memcpy implemented in MOPS instructions.  */
+  __asm__ volatile ("cpyfp   [%0]!, [%1]!, %2!\n\t"
+		    "cpyfm   [%0]!, [%1]!, %2!\n\t"
+		    "cpyfe   [%0]!, [%1]!, %2!\n\t"
+		    : "+&r" (p), "+&r" (q), "+&r" (size)
+		    :
+		    : "memory");
+
+  return 0;
+}
diff --git a/gdb/testsuite/gdb.arch/aarch64-mops-watchpoint.exp b/gdb/testsuite/gdb.arch/aarch64-mops-watchpoint.exp
new file mode 100644
index 000000000000..9e210602d800
--- /dev/null
+++ b/gdb/testsuite/gdb.arch/aarch64-mops-watchpoint.exp
@@ -0,0 +1,79 @@
+# 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 MOPS (Memory Operations) instructions.
+# This test is similar to gdb.base/memops-watchpoint.exp, but specifically
+# tests MOPS instructions rather than whatever instructions are used in the
+# system libc's implementation of memset/memcpy/memmove.
+
+require allow_hw_watchpoint_tests allow_aarch64_mops_tests
+
+standard_testfile
+
+if { [prepare_for_testing "failed to prepare" ${testfile} ${srcfile} \
+	  [list debug additional_flags=-march=armv9.3-a]] } {
+    return -1
+}
+
+set linespec ${srcfile}:[gdb_get_line_number "Break here"]
+if ![runto ${linespec}] {
+    return -1
+}
+
+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"
+
+gdb_test "continue" \
+    [multi_line \
+	 "Continuing\\." \
+	 "" \
+	 "Hardware watchpoint ${decimal}: -location a\\\[28\\\]" \
+	 "" \
+	 "Old value = 104 'h'" \
+	 "New value = 0 '\\\\000'" \
+	 "$hex in main \\(\\) at .*aarch64-mops-watchpoint.c:$decimal" \
+	 "${decimal}\\s+__asm__ volatile \\(\"setp.*\\\\n\\\\t\""] \
+    "continue until set watchpoint hits"
+
+gdb_test "continue" \
+    [multi_line \
+	 "Continuing\\." \
+	 "" \
+	 "Hardware watchpoint ${decimal}: -location b\\\[28\\\]" \
+	 "" \
+	 "Old value = 101 'e'" \
+	 "New value = 114 'r'" \
+	 "$hex in main \\(\\) at .*aarch64-mops-watchpoint.c:$decimal" \
+	 "${decimal}\\s+__asm__ volatile \\(\"cpyp.*\\\\n\\\\t\""] \
+    "continue until cpy watchpoint hits"
+
+gdb_test "continue" \
+    [multi_line \
+	 "Continuing\\." \
+	 "" \
+	 "Hardware watchpoint ${decimal}: -location c\\\[28\\\]" \
+	 "" \
+	 "Old value = 100 'd'" \
+	 "New value = 114 'r'" \
+	 "$hex in main \\(\\) at .*aarch64-mops-watchpoint.c:$decimal" \
+	 "${decimal}\\s+__asm__ volatile \\(\"cpyfp.*\\\\n\\\\t\""] \
+    "continue until cpyf watchpoint hits"
diff --git a/gdb/testsuite/lib/gdb.exp b/gdb/testsuite/lib/gdb.exp
index fe3f05c18df9..78c926ac80b6 100644
--- a/gdb/testsuite/lib/gdb.exp
+++ b/gdb/testsuite/lib/gdb.exp
@@ -4497,6 +4497,67 @@ proc aarch64_supports_sme_svl { length } {
     return 1
 }
 
+# Run a test on the target to see if it supports Aarch64 MOPS (Memory
+# Operations) extensions.  Return 0 if so, 1 if it does not.  Note this causes
+# a restart of GDB.
+
+gdb_caching_proc allow_aarch64_mops_tests {} {
+    global srcdir subdir gdb_prompt inferior_exited_re
+
+    set me "allow_aarch64_mops_tests"
+
+    if { ![is_aarch64_target]} {
+	return 0
+    }
+
+    # ARMv9.3-A contains the MOPS extension.  The test program doesn't use it,
+    # but take the opportunity to check whether the toolchain knows about MOPS.
+    set compile_flags "{additional_flags=-march=armv9.3-a}"
+
+    # Compile a program that tests the MOPS feature.
+    set src {
+	#include <stdbool.h>
+	#include <sys/auxv.h>
+
+	#ifndef HWCAP2_MOPS
+	#define HWCAP2_MOPS (1UL << 43)
+	#endif
+
+	int main() {
+	    bool mops_supported = getauxval (AT_HWCAP2) & HWCAP2_MOPS;
+
+	    return !mops_supported;
+	}
+    }
+
+    if {![gdb_simple_compile $me $src executable $compile_flags]} {
+	return 0
+    }
+
+    # Compilation succeeded so now run it via gdb.
+    clean_restart $obj
+    gdb_run_cmd
+    gdb_expect {
+	-re ".*$inferior_exited_re with code 01.*${gdb_prompt} $" {
+	    verbose -log "\n$me mops support not detected"
+	    set allow_mops_tests 0
+	}
+	-re ".*$inferior_exited_re normally.*${gdb_prompt} $" {
+	    verbose -log "\n$me: mops support detected"
+	    set allow_mops_tests 1
+	}
+	default {
+	  warning "\n$me: default case taken"
+	    set allow_mops_tests 0
+	}
+    }
+    gdb_exit
+    remote_file build delete $obj
+
+    verbose "$me:  returning $allow_mops_tests" 2
+    return $allow_mops_tests
+}
+
 # A helper that compiles a test case to see if __int128 is supported.
 proc gdb_int128_helper {lang} {
     return [gdb_can_simple_compile "i128-for-$lang" {