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[71.211.170.195]) by smtp.gmail.com with ESMTPSA id bn29-20020a056e02339d00b00363c664cfeasm2622692ilb.61.2024.02.13.08.58.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 13 Feb 2024 08:58:57 -0800 (PST) From: Tom Tromey Date: Tue, 13 Feb 2024 09:58:54 -0700 Subject: [PATCH v2 2/2] Add return value to DAP scope MIME-Version: 1.0 Message-Id: <20240213-dap-finish-v2-2-d507b889d735@adacore.com> References: <20240213-dap-finish-v2-0-d507b889d735@adacore.com> In-Reply-To: <20240213-dap-finish-v2-0-d507b889d735@adacore.com> To: gdb-patches@sourceware.org Cc: =?utf-8?q?K=C3=A9vin_Le_Gouguec?= X-Mailer: b4 0.12.4 X-Spam-Status: No, score=-11.2 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, GIT_PATCH_0, KAM_SHORT, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org X-BeenThere: gdb-patches@sourceware.org X-Mailman-Version: 2.1.30 Precedence: list List-Id: Gdb-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: gdb-patches-bounces+patchwork=sourceware.org@sourceware.org A bug report in the DAP specification repository pointed out that it is typical for DAP implementations to put a function's return value into the outermost scope. This patch changes gdb to follow this convention. Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=31341 Reviewed-By: Kévin Le Gouguec --- gdb/python/lib/gdb/dap/events.py | 3 ++ gdb/python/lib/gdb/dap/scopes.py | 39 +++++++++++++++++- gdb/testsuite/gdb.dap/step-out.c | 36 +++++++++++++++++ gdb/testsuite/gdb.dap/step-out.exp | 82 ++++++++++++++++++++++++++++++++++++++ 4 files changed, 158 insertions(+), 2 deletions(-) diff --git a/gdb/python/lib/gdb/dap/events.py b/gdb/python/lib/gdb/dap/events.py index 41302229ee5..928f23fd3ff 100644 --- a/gdb/python/lib/gdb/dap/events.py +++ b/gdb/python/lib/gdb/dap/events.py @@ -15,6 +15,7 @@ import gdb +from .scopes import set_finish_value from .server import send_event from .startup import exec_and_log, in_gdb_thread, log from .modules import is_module, make_module @@ -218,6 +219,8 @@ def _on_stop(event): } if isinstance(event, gdb.BreakpointEvent): obj["hitBreakpointIds"] = [x.number for x in event.breakpoints] + if hasattr(event, "details") and "finish-value" in event.details: + set_finish_value(event.details["finish-value"]) global _expected_pause global _expected_stop_reason diff --git a/gdb/python/lib/gdb/dap/scopes.py b/gdb/python/lib/gdb/dap/scopes.py index ff553259ea9..be2c382b40b 100644 --- a/gdb/python/lib/gdb/dap/scopes.py +++ b/gdb/python/lib/gdb/dap/scopes.py @@ -25,17 +25,32 @@ from .varref import BaseReference frame_to_scope = {} +# If the most recent stop was due to a 'finish', and the return value +# could be computed, then this holds that value. Otherwise it holds +# None. +_last_return_value = None + + # When the inferior is re-started, we erase all scope references. See # the section "Lifetime of Objects References" in the spec. @in_gdb_thread def clear_scopes(event): global frame_to_scope frame_to_scope = {} + global _last_return_value + _last_return_value = None gdb.events.cont.connect(clear_scopes) +@in_gdb_thread +def set_finish_value(val): + """Set the current 'finish' value on a stop.""" + global _last_return_value + _last_return_value = val + + # A helper function to compute the value of a symbol. SYM is either a # gdb.Symbol, or an object implementing the SymValueWrapper interface. # FRAME is a frame wrapper, as produced by a frame filter. Returns a @@ -76,7 +91,7 @@ class _ScopeReference(BaseReference): result["presentationHint"] = self.hint # How would we know? result["expensive"] = False - result["namedVariables"] = len(self.var_list) + result["namedVariables"] = self.child_count() if self.line is not None: result["line"] = self.line # FIXME construct a Source object @@ -93,6 +108,22 @@ class _ScopeReference(BaseReference): return symbol_value(self.var_list[idx], self.frame) +# A _ScopeReference that prepends the most recent return value. Note +# that this object is only created if such a value actually exists. +class _FinishScopeReference(_ScopeReference): + def __init__(self, *args): + super().__init__(*args) + + def child_count(self): + return super().child_count() + 1 + + def fetch_one_child(self, idx): + if idx == 0: + global _last_return_value + return ("(return)", _last_return_value) + return super().fetch_one_child(idx - 1) + + class _RegisterReference(_ScopeReference): def __init__(self, name, frame): super().__init__( @@ -109,6 +140,7 @@ class _RegisterReference(_ScopeReference): @request("scopes") def scopes(*, frameId: int, **extra): + global _last_return_value global frame_to_scope if frameId in frame_to_scope: scopes = frame_to_scope[frameId] @@ -120,10 +152,13 @@ def scopes(*, frameId: int, **extra): args = tuple(frame.frame_args() or ()) if args: scopes.append(_ScopeReference("Arguments", "arguments", frame, args)) + has_return_value = frameId == 0 and _last_return_value is not None # Make sure to handle the None case as well as the empty # iterator case. locs = tuple(frame.frame_locals() or ()) - if locs: + if has_return_value: + scopes.append(_FinishScopeReference("Locals", "locals", frame, locs)) + elif locs: scopes.append(_ScopeReference("Locals", "locals", frame, locs)) scopes.append(_RegisterReference("Registers", frame)) frame_to_scope[frameId] = scopes diff --git a/gdb/testsuite/gdb.dap/step-out.c b/gdb/testsuite/gdb.dap/step-out.c new file mode 100644 index 00000000000..8c7e6942342 --- /dev/null +++ b/gdb/testsuite/gdb.dap/step-out.c @@ -0,0 +1,36 @@ +/* Copyright 2024 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 . */ + +struct result +{ + int x; +}; + +struct result +function_breakpoint_here (int q) +{ + struct result val; + val.x = q; + return val; +} + +int +main () +{ + int q = 23; + return function_breakpoint_here (q).x - q; +} diff --git a/gdb/testsuite/gdb.dap/step-out.exp b/gdb/testsuite/gdb.dap/step-out.exp new file mode 100644 index 00000000000..757f4ebdaca --- /dev/null +++ b/gdb/testsuite/gdb.dap/step-out.exp @@ -0,0 +1,82 @@ +# 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 . + +# Test that stepOut puts the return value in scope. + +require allow_dap_tests + +load_lib dap-support.exp + +standard_testfile + +if {[build_executable ${testfile}.exp $testfile] == -1} { + return +} + +if {[dap_initialize] == ""} { + return +} + +set obj [dap_check_request_and_response "set breakpoint on function" \ + setFunctionBreakpoints \ + {o breakpoints [a [o name [s function_breakpoint_here]]]}] +set fn_bpno [dap_get_breakpoint_number $obj] + +dap_check_request_and_response "configurationDone" configurationDone + +if {[dap_launch $testfile] == ""} { + return +} +dap_wait_for_event_and_check "inferior started" thread "body reason" started + +dap_wait_for_event_and_check "stopped at function breakpoint" stopped \ + "body reason" breakpoint \ + "body hitBreakpointIds" $fn_bpno + +dap_check_request_and_response "return from function" stepOut \ + {o threadId [i 1]} +dap_wait_for_event_and_check "stopped after return" stopped \ + "body reason" step + +set bt [lindex [dap_check_request_and_response "backtrace" stackTrace \ + {o threadId [i 1]}] \ + 0] +set frame_id [dict get [lindex [dict get $bt body stackFrames] 0] id] + +set scopes [dap_check_request_and_response "get scopes" scopes \ + [format {o frameId [i %d]} $frame_id]] +set scopes [dict get [lindex $scopes 0] body scopes] + +gdb_assert {[llength $scopes] == 2} "two scopes" + +lassign $scopes scope reg_scope +gdb_assert {[dict get $scope name] == "Locals"} "scope is locals" +gdb_assert {[dict get $scope presentationHint] == "locals"} \ + "locals presentation hint" +gdb_assert {[dict get $scope namedVariables] == 2} "two vars in scope" + +set num [dict get $scope variablesReference] +set refs [lindex [dap_check_request_and_response "fetch arguments" \ + "variables" \ + [format {o variablesReference [i %d]} $num]] \ + 0] +set varlist [lindex [dict get $refs body variables] 0] + +gdb_assert {[dict get $varlist variablesReference] > 0} \ + "variable has children" +gdb_assert {[dict get $varlist name] == "(return)"} \ + "variable is return value" + +dap_shutdown