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[71.211.160.49]) by smtp.gmail.com with ESMTPSA id h11-20020a056602154b00b006814fd71117sm1203228iow.12.2022.10.07.11.01.32 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 07 Oct 2022 11:01:32 -0700 (PDT) To: gdb-patches@sourceware.org Subject: [PATCH 4/9] Introduce value_at_non_lval Date: Fri, 7 Oct 2022 12:01:15 -0600 Message-Id: <20221007180120.1866772-5-tromey@adacore.com> X-Mailer: git-send-email 2.34.3 In-Reply-To: <20221007180120.1866772-1-tromey@adacore.com> References: <20221007180120.1866772-1-tromey@adacore.com> MIME-Version: 1.0 X-Spam-Status: No, score=-11.3 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, GIT_PATCH_0, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP 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: 2.1.29 Precedence: list List-Id: Gdb-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-Patchwork-Original-From: Tom Tromey via Gdb-patches From: Tom Tromey Reply-To: Tom Tromey Cc: Tom Tromey Errors-To: gdb-patches-bounces+patchwork=sourceware.org@sourceware.org Sender: "Gdb-patches" In some cases, while a value might be read from memory, gdb should not record the value as being equivalent to that memory. In Ada, the inferior call code will call ada_convert_actual -- and here, if the argument is already in memory, that address will simply be reused. However, for a call like "f(g())", the result of "g" might be on the stack and thus overwritten by the call to "f". This patch introduces a new function that is like value_at but that ensures that the result is non-lvalue. --- gdb/valops.c | 10 ++++++++++ gdb/value.h | 4 ++++ 2 files changed, 14 insertions(+) diff --git a/gdb/valops.c b/gdb/valops.c index de8a68888e4..be4ce025c89 100644 --- a/gdb/valops.c +++ b/gdb/valops.c @@ -1018,6 +1018,16 @@ value_at (struct type *type, CORE_ADDR addr) return get_value_at (type, addr, 0); } +/* See value.h. */ + +struct value * +value_at_non_lval (struct type *type, CORE_ADDR addr) +{ + struct value *result = value_at (type, addr); + VALUE_LVAL (result) = not_lval; + return result; +} + /* Return a lazy value with type TYPE located at ADDR (cf. value_at). The type of the created value may differ from the passed type TYPE. Make sure to retrieve the returned values's new type after this call diff --git a/gdb/value.h b/gdb/value.h index 52752df1f4c..86e06a54d7d 100644 --- a/gdb/value.h +++ b/gdb/value.h @@ -690,6 +690,10 @@ extern struct value *value_from_component (struct value *, struct type *, extern struct value *value_at (struct type *type, CORE_ADDR addr); extern struct value *value_at_lazy (struct type *type, CORE_ADDR addr); +/* Like value_at, but ensures that the result is marked not_lval. + This can be important if the memory is "volatile". */ +extern struct value *value_at_non_lval (struct type *type, CORE_ADDR addr); + extern struct value *value_from_contents_and_address_unresolved (struct type *, const gdb_byte *, CORE_ADDR); extern struct value *value_from_contents_and_address (struct type *,