From: Tom Tromey Date: Thu, 1 Jun 2023 17:54:17 +0000 (-0600) Subject: Implement DAP "hover" context X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=d8a001f57016eff05977e9699c7aabdf4302c71b;p=binutils-gdb.git Implement DAP "hover" context 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 --- 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 . */ + +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 . + +# 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