From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm1-x32d.google.com (mail-wm1-x32d.google.com [IPv6:2a00:1450:4864:20::32d]) by sourceware.org (Postfix) with ESMTPS id 31E7D3858C2C for ; Fri, 1 Oct 2021 11:02:17 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 31E7D3858C2C Received: by mail-wm1-x32d.google.com with SMTP id m14-20020a05600c3b0e00b0030d4dffd04fso1157378wms.3 for ; Fri, 01 Oct 2021 04:02:17 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=zLnq86QTu8SrjGpijJvhfFuoV2rBN5Hoj76I4rg/J0k=; b=3segkqnRIMGdW+E+zNmYbZjLH3+XdyuoBaimRkarcvkSZ9PC0QlQy4cW5ME74MWJV4 Rmkm70nq0Slm12hFYmrD1B1qfO2DfbH42rHPD1+ydQXCVu+NVwpbb973eDPHQkvweZJ+ TNra68uhISEn0h2CO88vaVtKNwYIzaW7GgrKiGI2F3/MEX2PxsGe27/cCN/LTk41l7Ns n+sfVJdfl8Xf6DJkABYt9RbTIu1q5/HTNnyPgpi9kTZ5ZA/ikz0rnxmOmpKmEm1AjTdo 4hv35KVUWRf6zEb7B4WCc9farOxkejB57P9u/QE8JMFUF+tjdfzpIcvc+Oer+w0z9ajf dlew== X-Gm-Message-State: AOAM531KkSSSg7d7+w9zbSfHKD8cFFAesna22ZHyBbe7U7VVSrcDsZ1R qHxnEKBuwSzxvz6VFaurjMWziGJ28ZTzdLgVU5jMMw== X-Google-Smtp-Source: ABdhPJzGGH/wrUU8jqtWsb/JIXZXACsJB3HoW4Z7WNF1fI72fffc6YnsH+IN2VYBz6Oum4W7cqNgr101IGBx2ZyCXKY= X-Received: by 2002:a05:600c:1d18:: with SMTP id l24mr3937752wms.98.1633086135742; Fri, 01 Oct 2021 04:02:15 -0700 (PDT) MIME-Version: 1.0 References: <1632111261-18790-1-git-send-email-apinski@marvell.com> In-Reply-To: <1632111261-18790-1-git-send-email-apinski@marvell.com> From: Eric Gallager Date: Fri, 1 Oct 2021 07:02:04 -0400 Message-ID: Subject: Re: [PATCH] c: [PR32122] Require pointer types for computed gotos To: apinski@marvell.com Cc: gcc-patches Content-Type: text/plain; charset="UTF-8" X-Spam-Status: No, score=-8.8 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, GIT_PATCH_0, JMQ_SPF_NEUTRAL, 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-List-Received-Date: Fri, 01 Oct 2021 11:02:20 -0000 On Mon, Sep 20, 2021 at 12:15 AM apinski--- via Gcc-patches wrote: > > From: Andrew Pinski > > So GCC has always accepted non-pointer types in computed gotos but > that was wrong based on the documentation: > Any expression of type void * is allowed. > > So this fixes the problem by requiring the type to > be a pointer type. > > OK? Bootstrapped and tested on x86_64-linux-gnu with no regressions. > > PR c/32122 > > gcc/c/ChangeLog: > > * c-parser.c (c_parser_statement_after_labels): Pass > the c_expr instead of the tree to c_finish_goto_ptr. > * c-typeck.c (c_finish_goto_ptr): Change the second > argument type to c_expr. > * c-tree.h (c_finish_goto_ptr): Likewise. > Error out if the expression was not of a pointer type. > > gcc/testsuite/ChangeLog: > > * gcc.dg/comp-goto-5.c: New test. > * gcc.dg/comp-goto-6.c: New test. > --- > gcc/c/c-parser.c | 2 +- > gcc/c/c-tree.h | 2 +- > gcc/c/c-typeck.c | 11 ++++++++++- > gcc/testsuite/gcc.dg/comp-goto-5.c | 11 +++++++++++ > gcc/testsuite/gcc.dg/comp-goto-6.c | 6 ++++++ > 5 files changed, 29 insertions(+), 3 deletions(-) > create mode 100644 gcc/testsuite/gcc.dg/comp-goto-5.c > create mode 100644 gcc/testsuite/gcc.dg/comp-goto-6.c > > diff --git a/gcc/c/c-parser.c b/gcc/c/c-parser.c > index fb1399e300d..bcd8a05489f 100644 > --- a/gcc/c/c-parser.c > +++ b/gcc/c/c-parser.c > @@ -6141,7 +6141,7 @@ c_parser_statement_after_labels (c_parser *parser, bool *if_p, > c_parser_consume_token (parser); > val = c_parser_expression (parser); > val = convert_lvalue_to_rvalue (loc, val, false, true); > - stmt = c_finish_goto_ptr (loc, val.value); > + stmt = c_finish_goto_ptr (loc, val); > } > else > c_parser_error (parser, "expected identifier or %<*%>"); > diff --git a/gcc/c/c-tree.h b/gcc/c/c-tree.h > index d50d0cb7f2d..a046c6b0926 100644 > --- a/gcc/c/c-tree.h > +++ b/gcc/c/c-tree.h > @@ -746,7 +746,7 @@ extern tree c_finish_expr_stmt (location_t, tree); > extern tree c_finish_return (location_t, tree, tree); > extern tree c_finish_bc_stmt (location_t, tree, bool); > extern tree c_finish_goto_label (location_t, tree); > -extern tree c_finish_goto_ptr (location_t, tree); > +extern tree c_finish_goto_ptr (location_t, c_expr val); > extern tree c_expr_to_decl (tree, bool *, bool *); > extern tree c_finish_omp_construct (location_t, enum tree_code, tree, tree); > extern tree c_finish_oacc_data (location_t, tree, tree); > diff --git a/gcc/c/c-typeck.c b/gcc/c/c-typeck.c > index 49d1bb067a0..b472e448011 100644 > --- a/gcc/c/c-typeck.c > +++ b/gcc/c/c-typeck.c > @@ -10783,10 +10783,19 @@ c_finish_goto_label (location_t loc, tree label) > the GOTO. */ > > tree > -c_finish_goto_ptr (location_t loc, tree expr) > +c_finish_goto_ptr (location_t loc, c_expr val) > { > + tree expr = val.value; > tree t; > pedwarn (loc, OPT_Wpedantic, "ISO C forbids %"); > + if (expr != error_mark_node > + && !POINTER_TYPE_P (TREE_TYPE (expr)) > + && !null_pointer_constant_p (expr)) > + { > + error_at (val.get_location (), > + "computed goto must be pointer type"); > + expr = build_zero_cst (ptr_type_node); > + } > expr = c_fully_fold (expr, false, NULL); > expr = convert (ptr_type_node, expr); > t = build1 (GOTO_EXPR, void_type_node, expr); > diff --git a/gcc/testsuite/gcc.dg/comp-goto-5.c b/gcc/testsuite/gcc.dg/comp-goto-5.c > new file mode 100644 > index 00000000000..d487729a5d4 > --- /dev/null > +++ b/gcc/testsuite/gcc.dg/comp-goto-5.c > @@ -0,0 +1,11 @@ > +/* PR c/32122 */ > +/* { dg-do compile } */ > +/* { dg-options "" } */ > + > +enum {a=1}; > +void foo() > +{ > + goto * > + a; /* { dg-error "computed goto must be pointer type" } */ > +} > + > diff --git a/gcc/testsuite/gcc.dg/comp-goto-6.c b/gcc/testsuite/gcc.dg/comp-goto-6.c > new file mode 100644 > index 00000000000..497f6cd76ca > --- /dev/null > +++ b/gcc/testsuite/gcc.dg/comp-goto-6.c > @@ -0,0 +1,6 @@ > +/* PR c/32122 */ > +/* { dg-do compile } */ > +/* { dg-options "" } */ > +void foo(void *a) { goto *10000000; } /* { dg-error "computed goto must be pointer type" } */ > +void foo1(void *a) { goto *a; } > + > -- > 2.17.1 > Maybe add to one of the testcases a test to ensure that the cast-to-void workaround works successfully? e.g. void foo2(void *a) { goto *(void *)10000000; } /* { dg-bogus "computed goto must be pointer type" } */