From: Tom Tromey <tromey@adacore.com>
To: gdb-patches@sourceware.org
Subject: [PATCH 7/7] Implement DAP "hover" context
Date: Mon, 12 Jun 2023 13:36:34 -0600 [thread overview]
Message-ID: <20230612-more-dap-v1-7-ad868f1a4cc0@adacore.com> (raw)
In-Reply-To: <20230612-more-dap-v1-0-ad868f1a4cc0@adacore.com>
A DAP client can request that an expression be evaluated in "hover"
context, meaning that it should not cause side effects. In gdb, this
can be implemented by temporarily setting a few "may-" parameters to
"off".
In order to make this work, I had to also change "may-write-registers"
so that it can be changed while the program is running. I don't think
there was any reason for this prohibition in the first place.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=30476
---
gdb/python/lib/gdb/dap/evaluate.py | 13 +++++++
gdb/target.c | 12 +++----
gdb/testsuite/gdb.dap/hover.c | 30 ++++++++++++++++
gdb/testsuite/gdb.dap/hover.exp | 70 ++++++++++++++++++++++++++++++++++++++
4 files changed, 119 insertions(+), 6 deletions(-)
diff --git a/gdb/python/lib/gdb/dap/evaluate.py b/gdb/python/lib/gdb/dap/evaluate.py
index a0b199a1ed4..651a4046a34 100644
--- a/gdb/python/lib/gdb/dap/evaluate.py
+++ b/gdb/python/lib/gdb/dap/evaluate.py
@@ -43,6 +43,16 @@ def _evaluate(expr, frame_id):
return ref.to_object()
+# Like _evaluate but ensure that the expression cannot cause side
+# effects.
+@in_gdb_thread
+def _eval_for_hover(expr, frame_id):
+ with gdb.with_parameter("may-write-registers", "off"):
+ with gdb.with_parameter("may-write-memory", "off"):
+ with gdb.with_parameter("may-call-functions", "off"):
+ return _evaluate(expr, frame_id)
+
+
# Helper function to perform an assignment.
@in_gdb_thread
def _set_expression(expression, value, frame_id):
@@ -71,6 +81,7 @@ def _repl(command, frame_id):
@request("evaluate")
+@capability("supportsEvaluateForHovers")
def eval_request(
*,
expression: str,
@@ -81,6 +92,8 @@ def eval_request(
if context in ("watch", "variables"):
# These seem to be expression-like.
return send_gdb_with_response(lambda: _evaluate(expression, frameId))
+ elif context == "hover":
+ return send_gdb_with_response(lambda: _eval_for_hover(expression, frameId))
elif context == "repl":
return send_gdb_with_response(lambda: _repl(expression, frameId))
else:
diff --git a/gdb/target.c b/gdb/target.c
index 80d2c80d4bf..fecbc89d3ca 100644
--- a/gdb/target.c
+++ b/gdb/target.c
@@ -4494,7 +4494,6 @@ set_target_permissions (const char *args, int from_tty,
}
/* Make the real values match the user-changed values. */
- may_write_registers = may_write_registers_1;
may_insert_breakpoints = may_insert_breakpoints_1;
may_insert_tracepoints = may_insert_tracepoints_1;
may_insert_fast_tracepoints = may_insert_fast_tracepoints_1;
@@ -4502,14 +4501,15 @@ set_target_permissions (const char *args, int from_tty,
update_observer_mode ();
}
-/* Set memory write permission independently of observer mode. */
+/* Set some permissions independently of observer mode. */
static void
-set_write_memory_permission (const char *args, int from_tty,
- struct cmd_list_element *c)
+set_write_memory_registers_permission (const char *args, int from_tty,
+ struct cmd_list_element *c)
{
/* Make the real values match the user-changed values. */
may_write_memory = may_write_memory_1;
+ may_write_registers = may_write_registers_1;
update_observer_mode ();
}
@@ -4578,7 +4578,7 @@ Set permission to write into registers."), _("\
Show permission to write into registers."), _("\
When this permission is on, GDB may write into the target's registers.\n\
Otherwise, any sort of write attempt will result in an error."),
- set_target_permissions, NULL,
+ set_write_memory_registers_permission, NULL,
&setlist, &showlist);
add_setshow_boolean_cmd ("may-write-memory", class_support,
@@ -4587,7 +4587,7 @@ Set permission to write into target memory."), _("\
Show permission to write into target memory."), _("\
When this permission is on, GDB may write into the target's memory.\n\
Otherwise, any sort of write attempt will result in an error."),
- set_write_memory_permission, NULL,
+ set_write_memory_registers_permission, NULL,
&setlist, &showlist);
add_setshow_boolean_cmd ("may-insert-breakpoints", class_support,
diff --git a/gdb/testsuite/gdb.dap/hover.c b/gdb/testsuite/gdb.dap/hover.c
new file mode 100644
index 00000000000..f85339612cd
--- /dev/null
+++ b/gdb/testsuite/gdb.dap/hover.c
@@ -0,0 +1,30 @@
+/* Copyright 2023 Free Software Foundation, Inc.
+
+ This file is part of GDB.
+
+ 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 global_variable = 23;
+
+int
+increment ()
+{
+ return ++global_variable;
+}
+
+int
+main ()
+{
+ return 0; /* BREAK */
+}
diff --git a/gdb/testsuite/gdb.dap/hover.exp b/gdb/testsuite/gdb.dap/hover.exp
new file mode 100644
index 00000000000..4caf105b347
--- /dev/null
+++ b/gdb/testsuite/gdb.dap/hover.exp
@@ -0,0 +1,70 @@
+# 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/>.
+
+# Test DAP "hover" evaluation.
+
+require allow_dap_tests
+
+load_lib dap-support.exp
+
+standard_testfile
+
+if {[build_executable ${testfile}.exp $testfile] == -1} {
+ return
+}
+
+if {[dap_launch $testfile] == ""} {
+ return
+}
+
+set line [gdb_get_line_number "BREAK"]
+set obj [dap_check_request_and_response "set breakpoint by line number" \
+ setBreakpoints \
+ [format {o source [o path [%s]] breakpoints [a [o line [i %d]]]} \
+ [list s $srcfile] $line]]
+set line_bpno [dap_get_breakpoint_number $obj]
+
+dap_check_request_and_response "start inferior" configurationDone
+dap_wait_for_event_and_check "inferior started" thread "body reason" started
+
+dap_wait_for_event_and_check "stopped at breakpoint" stopped \
+ "body reason" breakpoint \
+ "body hitBreakpointIds" $line_bpno
+
+set obj [dap_check_request_and_response "evaluate global" \
+ evaluate {o expression [s global_variable]}]
+dap_match_values "global value in function" [lindex $obj 0] \
+ "body result" 23
+
+set obj [dap_request_and_response \
+ evaluate {o context [s hover] expression [s increment()]}]
+gdb_assert {[dict get [lindex $obj 0] success] == "false"} \
+ "increment was rejected in hover mode"
+
+dap_check_request_and_response "call increment" \
+ evaluate {o expression [s increment()]}
+
+set obj [dap_request_and_response \
+ evaluate {o context [s hover] \
+ expression [s "global_variable = -1"]}]
+gdb_assert {[dict get [lindex $obj 0] success] == "false"} \
+ "assignment was rejected in hover mode"
+
+set obj [dap_check_request_and_response "evaluate global again" \
+ evaluate {o expression [s global_variable]}]
+dap_match_values "global value incremented once" [lindex $obj 0] \
+ "body result" 24
+
+dap_shutdown
--
2.40.1
next prev parent reply other threads:[~2023-06-12 19:36 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-12 19:36 [PATCH 0/7] More changes to DAP Tom Tromey
2023-06-12 19:36 ` [PATCH 1/7] Fix type of DAP hitCondition Tom Tromey
2023-06-12 19:36 ` [PATCH 2/7] Reuse breakpoints more frequently in DAP Tom Tromey
2023-06-12 19:36 ` [PATCH 3/7] Handle exceptions when creating DAP breakpoints Tom Tromey
2023-06-12 19:36 ` [PATCH 4/7] Implement type checking for DAP breakpoint requests Tom Tromey
2023-06-12 19:36 ` [PATCH 5/7] Handle supportsVariablePaging in DAP Tom Tromey
2023-06-12 19:36 ` [PATCH 6/7] Implement DAP logging breakpoints Tom Tromey
2023-06-12 19:36 ` Tom Tromey [this message]
2023-06-22 15:46 ` [PATCH 0/7] More changes to DAP Tom Tromey
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