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[184.96.250.76]) by smtp.gmail.com with ESMTPSA id j126sm5168111qke.103.2021.11.22.15.00.57 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 22 Nov 2021 15:00:57 -0800 (PST) To: gcc-patches , Jason Merrill Subject: [PATCH] handle member references in -Waddress [PR96507] Message-ID: Date: Mon, 22 Nov 2021 16:00:56 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.2.2 MIME-Version: 1.0 Content-Language: en-US X-Spam-Status: No, score=-10.4 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, FREEMAIL_FROM, GIT_PATCH_0, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org X-BeenThere: gcc-patches@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gcc-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-Patchwork-Original-From: Martin Sebor via Gcc-patches From: Martin Sebor Reply-To: Martin Sebor Errors-To: gcc-patches-bounces+patchwork=sourceware.org@gcc.gnu.org Sender: "Gcc-patches" While going through old -Waddress bug reports to close after the recent improvements to the warning I came across PR 96507 that points out that member references aren't handled. Since testing the address of a reference for equality to null is in general diagnosed, this seems like an oversight worth fixing. Attached is a change to the C++ front end to diagnose member references as well. Tested on x86_64-linux. Martin Issue -Waddress also for reference members [PR96507]. Resolves: PR c++/96507 - missing -Waddress for member references gcc/cp/ChangeLog: PR c++/96507 * typeck.c (warn_for_null_address): Handle reference members. gcc/testsuite/ChangeLog: PR c++/96507 * g++.dg/warn/Waddress-8.C: New test. diff --git a/gcc/cp/typeck.c b/gcc/cp/typeck.c index 58919aaf13e..694c53eef8a 100644 --- a/gcc/cp/typeck.c +++ b/gcc/cp/typeck.c @@ -4676,15 +4676,21 @@ warn_for_null_address (location_t location, tree op, tsubst_flags_t complain) "addition %qE and NULL", cop); return; } - else if (CONVERT_EXPR_P (op) - && TYPE_REF_P (TREE_TYPE (TREE_OPERAND (op, 0)))) + else if (CONVERT_EXPR_P (op)) { - STRIP_NOPS (op); + tree op0 = TREE_OPERAND (op, 0); + if (TYPE_REF_P (TREE_TYPE (op0))) + { + STRIP_NOPS (op); + + if (TREE_CODE (op) == COMPONENT_REF) + op = TREE_OPERAND (op, 1); - if (DECL_P (op)) - warned = warning_at (location, OPT_Waddress, - "the compiler can assume that the address of " - "%qD will never be NULL", op); + if (DECL_P (op)) + warned = warning_at (location, OPT_Waddress, + "the compiler can assume that the address of " + "%qD will never be NULL", op); + } } if (warned && DECL_P (op)) diff --git a/gcc/testsuite/g++.dg/warn/Waddress-8.C b/gcc/testsuite/g++.dg/warn/Waddress-8.C new file mode 100644 index 00000000000..797102d6be4 --- /dev/null +++ b/gcc/testsuite/g++.dg/warn/Waddress-8.C @@ -0,0 +1,85 @@ +/* PR c++/96507 - missing -Waddress for member references + { dg-do compile } + { dg-options "-Wall" } */ + +typedef void F (); + +extern F 𝔢 +extern int &eir; + +bool warn_ext_rfun () +{ + return &efr != 0; // { dg-warning "-Waddress" } +} + +bool warn_ext_rvar () +{ + return &eir != 0; // { dg-warning "-Waddress" } +} + + +bool warn_parm_rfun (F &rf) +{ + return &rf != 0; // { dg-warning "-Waddress" } +} + +bool warn_parm_rvar (int &ir) +{ + return &ir != 0; // { dg-warning "-Waddress" } +} + +// Comparing the address of a reference argument to null also triggers +// a -Wnonnull-compare (that seems like a bug, hence PR 103363). +// { dg-prune-output "-Wnonnull-compare" } + + +struct S +{ + F &fr; + int &ir; +}; + +extern S es, esa[]; + +bool warn_ext_mem_rfun () +{ + return &es.fr != 0; // { dg-warning "-Waddress" } +} + +bool warn_ext_mem_rvar () +{ + return &es.ir != 0; // { dg-warning "-Waddress" } +} + + +bool warn_ext_arr_mem_rfun (int i) +{ + return &esa[i].fr != 0; // { dg-warning "-Waddress" } +} + +bool warn_ext_arr_mem_rvar (int i) +{ + return &esa[i].ir != 0; // { dg-warning "-Waddress" } +} + + +bool warn_parm_mem_rfun (S &s) +{ + return &s.fr != 0; // { dg-warning "-Waddress" } +} + +bool warn_parm_mem_rvar (S &s) +{ + return &s.ir != 0; // { dg-warning "-Waddress" } +} + + +bool warn_parm_arr_mem_rfun (S sa[], int i) +{ + return &sa[i].fr != 0; // { dg-warning "-Waddress" } +} + +bool warn_parm_arr_mem_rvar (S sa[], int i) +{ + return &sa[i].ir != 0; // { dg-warning "-Waddress" } +}