From patchwork Mon Jan 20 20:42:45 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tom Tromey X-Patchwork-Id: 312729 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from sourceware.org (server1.sourceware.org [209.132.180.131]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 902032C0089 for ; Tue, 21 Jan 2014 07:43:01 +1100 (EST) DomainKey-Signature: a=rsa-sha1; c=nofws; d=gcc.gnu.org; h=list-id :list-unsubscribe:list-archive:list-post:list-help:sender:from :to:subject:date:message-id:mime-version:content-type; q=dns; s= default; b=aKApKHYsZokIxDy3gRm2AnYGVDkQY2koChwMtYur/sRTNR7nC/hOC FSSLpyBZo4WOVvF/xWJql8UoBSqzLat7DYASWzAtPYuzVe4fFnTPGTq1rgB2LeND qpk9nxp7Nw+pai/qXXwjNsODFqYnFljx3gpb6bc12pplSEA1AiuZGk= DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=gcc.gnu.org; h=list-id :list-unsubscribe:list-archive:list-post:list-help:sender:from :to:subject:date:message-id:mime-version:content-type; s= default; bh=rYppbvQ6xtqwWCMDAhzleLdZtiY=; b=A4BG7oaB/tMs/Ua/F7Yj kbJAcvyVcRuZrncrzLw/9nMrQ5WStpuZuS635YGzh91pqUzxW8Ij+0j3yGvExkdm L+CJkpdyMyboPojk5ysPfsDzIIyFOOZ5QKaILc+KLeSQgGvY4jaYZpyFLX00NTuc FiWP1LFeFvwEhzO2sRKtPoc= Received: (qmail 18955 invoked by alias); 20 Jan 2014 20:42:55 -0000 Mailing-List: contact gcc-patches-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Archive: List-Post: List-Help: Sender: gcc-patches-owner@gcc.gnu.org Delivered-To: mailing list gcc-patches@gcc.gnu.org Received: (qmail 18936 invoked by uid 89); 20 Jan 2014 20:42:54 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-3.2 required=5.0 tests=AWL, BAYES_00, RP_MATCHES_RCVD, SPF_HELO_PASS, SPF_PASS autolearn=ham version=3.3.2 X-HELO: mx1.redhat.com Received: from mx1.redhat.com (HELO mx1.redhat.com) (209.132.183.28) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Mon, 20 Jan 2014 20:42:50 +0000 Received: from int-mx12.intmail.prod.int.phx2.redhat.com (int-mx12.intmail.prod.int.phx2.redhat.com [10.5.11.25]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id s0KKgm76031094 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Mon, 20 Jan 2014 15:42:48 -0500 Received: from barimba (ovpn-113-85.phx2.redhat.com [10.3.113.85]) by int-mx12.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id s0KKgkVM010060 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES128-SHA bits=128 verify=NO); Mon, 20 Jan 2014 15:42:46 -0500 From: Tom Tromey To: gcc-patches@gcc.gnu.org Subject: [PATCH] add __attribute__ ((designated_init)) Date: Mon, 20 Jan 2014 13:42:45 -0700 Message-ID: <874n4ygzay.fsf@fleche.redhat.com> MIME-Version: 1.0 This adds __attribute__((designated_init)) and -Wdesignated-init, a feature from sparse. This is also PR c/59855. The name of the attribute and the option were chosen to be compatible with sparse. I added this warning to -Wall since it seemed like the kind of warning users would ordinarily want -- if they are not using the attribute, they won't ever see it anyhow. I wrote a new test case covering the same cases that the sparse test case covers. I also added tests for applying the attribute to non-struct types; note that in this case sparse issues a warning but gcc issues an error. I think an error is more appropriate. Built and regtested on x86-64 Fedora 20. It's been a while but I think I did it properly. Tom --- gcc/ChangeLog | 7 +++ gcc/c-family/ChangeLog | 7 +++ gcc/c-family/c-common.c | 17 +++++++ gcc/c-family/c.opt | 4 ++ gcc/c/ChangeLog | 9 ++++ gcc/c/c-typeck.c | 12 +++++ gcc/doc/extend.texi | 11 +++++ gcc/doc/invoke.texi | 10 +++- gcc/testsuite/ChangeLog | 5 ++ gcc/testsuite/gcc.dg/Wdesignated-init.c | 82 +++++++++++++++++++++++++++++++++ 10 files changed, 163 insertions(+), 1 deletion(-) create mode 100644 gcc/testsuite/gcc.dg/Wdesignated-init.c diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 652d2c9..77e4d54 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,10 @@ +2014-01-20 Tom Tromey + + PR c/59855 + * doc/invoke.texi (Warning Options): Document -Wdesignated-init. + * doc/extend.texi (Type Attributes): Document designated_init + attribute. + 2014-01-19 John David Anglin * config/pa/pa.c (pa_attr_length_millicode_call): Correct length of diff --git a/gcc/c-family/ChangeLog b/gcc/c-family/ChangeLog index fede01f..7593791 100644 --- a/gcc/c-family/ChangeLog +++ b/gcc/c-family/ChangeLog @@ -1,3 +1,10 @@ +2014-01-20 Tom Tromey + + PR c/59855 + * c.opt (Wdesignated-init): New option. + * c-common.c (c_common_attribute_table): Add "designated_init". + (handle_designated_init): New function. + 2014-01-15 Laurent Alfonsi PR c++/49718 diff --git a/gcc/c-family/c-common.c b/gcc/c-family/c-common.c index 35958ea..e0a0653 100644 --- a/gcc/c-family/c-common.c +++ b/gcc/c-family/c-common.c @@ -377,6 +377,7 @@ static tree handle_omp_declare_simd_attribute (tree *, tree, tree, int, bool *); static tree handle_omp_declare_target_attribute (tree *, tree, tree, int, bool *); +static tree handle_designated_init (tree *, tree, tree, int, bool *); static void check_function_nonnull (tree, int, tree *); static void check_nonnull_arg (void *, tree, unsigned HOST_WIDE_INT); @@ -766,6 +767,8 @@ const struct attribute_spec c_common_attribute_table[] = handle_omp_declare_simd_attribute, false }, { "omp declare target", 0, 0, true, false, false, handle_omp_declare_target_attribute, false }, + { "designated_init", 0, 0, false, true, false, + handle_designated_init, false }, { NULL, 0, 0, false, false, false, NULL, false } }; @@ -9133,6 +9136,20 @@ handle_returns_nonnull_attribute (tree *node, tree, tree, int, return NULL_TREE; } +/* Handle a "designated_init" attribute; arguments as in + struct attribute_spec.handler. */ + +static tree +handle_designated_init (tree *node, tree, tree, int, bool *no_add_attrs) +{ + if (TREE_CODE (*node) != RECORD_TYPE) + { + error ("designated_init attribute is only valid on struct type"); + *no_add_attrs = true; + } + return NULL_TREE; +} + /* Check for valid arguments being passed to a function with FNTYPE. There are NARGS arguments in the array ARGARRAY. */ diff --git a/gcc/c-family/c.opt b/gcc/c-family/c.opt index 38ae58e..29ac4d0 100644 --- a/gcc/c-family/c.opt +++ b/gcc/c-family/c.opt @@ -355,6 +355,10 @@ Wdeprecated C C++ ObjC ObjC++ Var(warn_deprecated) Init(1) Warning Warn if a deprecated compiler feature, class, method, or field is used +Wdesignated-init +C ObjC Var(warn_designated_init) Init(0) Warning LangEnabledBy(C ObjC,Wall) +Warn about positional initialization of structs requiring designated initializers + Wdiv-by-zero C ObjC C++ ObjC++ Var(warn_div_by_zero) Init(1) Warning Warn about compile-time integer division by zero diff --git a/gcc/c/ChangeLog b/gcc/c/ChangeLog index 4754bdf..c34fe93 100644 --- a/gcc/c/ChangeLog +++ b/gcc/c/ChangeLog @@ -1,3 +1,12 @@ +2014-01-20 Tom Tromey + + * c-typeck.c (struct constructor_stack) : New + field. + (really_start_incremental_init, push_init_level): Initialize + designator_depth. + (pop_init_level): Set global designator_depth. + (process_init_element): Check for designated_init attribute. + 2014-01-15 Jakub Jelinek PR c/58943 diff --git a/gcc/c/c-typeck.c b/gcc/c/c-typeck.c index 09049e2..31a1f5a 100644 --- a/gcc/c/c-typeck.c +++ b/gcc/c/c-typeck.c @@ -6885,6 +6885,7 @@ struct constructor_stack char outer; char incremental; char designated; + int designator_depth; }; static struct constructor_stack *constructor_stack; @@ -7056,6 +7057,7 @@ really_start_incremental_init (tree type) p->outer = 0; p->incremental = constructor_incremental; p->designated = constructor_designated; + p->designator_depth = designator_depth; p->next = 0; constructor_stack = p; @@ -7201,6 +7203,7 @@ push_init_level (int implicit, struct obstack * braced_init_obstack) p->outer = 0; p->incremental = constructor_incremental; p->designated = constructor_designated; + p->designator_depth = designator_depth; p->next = constructor_stack; p->range_stack = 0; constructor_stack = p; @@ -7501,6 +7504,7 @@ pop_init_level (int implicit, struct obstack * braced_init_obstack) constructor_erroneous = p->erroneous; constructor_incremental = p->incremental; constructor_designated = p->designated; + designator_depth = p->designator_depth; constructor_pending_elts = p->pending_elts; constructor_depth = p->depth; if (!p->implicit) @@ -8558,6 +8562,14 @@ process_init_element (struct c_expr value, bool implicit, if (constructor_type == 0) return; + if (!implicit && warn_designated_init && !was_designated + && TREE_CODE (constructor_type) == RECORD_TYPE + && lookup_attribute ("designated_init", + TYPE_ATTRIBUTES (constructor_type))) + warning_init (OPT_Wdesignated_init, + "positional initialization of field " + "in struct declared with designated_init attribute"); + /* If we've exhausted any levels that didn't have braces, pop them now. */ while (constructor_stack->implicit) diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi index 2f4f91d..7cefeb1 100644 --- a/gcc/doc/extend.texi +++ b/gcc/doc/extend.texi @@ -5742,6 +5742,17 @@ and caught in another, the class must have default visibility. Otherwise the two shared objects are unable to use the same typeinfo node and exception handling will break. +@item designated_init +This attribute may only be applied to struct types. It indicates that +any initialization of an object of this type must use designated +initializers rather than positional initializers. The intent of this +attribute is to allow the programmer to indicate that a structure's +layout may change, and that therefore relying on positional +initialization will result in future breakage. + +GCC only emits a warning for this attribute when +@option{-Wdesignated-init} is given. + @end table To specify multiple attributes, separate them by commas within the diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi index ac4b597..fd5fb18 100644 --- a/gcc/doc/invoke.texi +++ b/gcc/doc/invoke.texi @@ -241,7 +241,8 @@ Objective-C and Objective-C++ Dialects}. -Wc++-compat -Wc++11-compat -Wcast-align -Wcast-qual @gol -Wchar-subscripts -Wclobbered -Wcomment -Wconditionally-supported @gol -Wconversion -Wcoverage-mismatch -Wdate-time -Wdelete-incomplete -Wno-cpp @gol --Wno-deprecated -Wno-deprecated-declarations -Wdisabled-optimization @gol +-Wno-deprecated -Wno-deprecated-declarations @gol +-Wdesignated-init -Wdisabled-optimization @gol -Wno-div-by-zero -Wdouble-promotion -Wempty-body -Wenum-compare @gol -Wno-endif-labels -Werror -Werror=* @gol -Wfatal-errors -Wfloat-equal -Wformat -Wformat=2 @gol @@ -3340,6 +3341,7 @@ Options} and @ref{Objective-C and Objective-C++ Dialect Options}. -Warray-bounds @r{(only with} @option{-O2}@r{)} @gol -Wc++11-compat @gol -Wchar-subscripts @gol +-Wdesignated-init @gol -Wenum-compare @r{(in C/ObjC; this is on by default in C++)} @gol -Wimplicit-int @r{(C and Objective-C only)} @gol -Wimplicit-function-declaration @r{(C and Objective-C only)} @gol @@ -5094,6 +5096,12 @@ a suffix. When used together with @option{-Wsystem-headers} it warns about such constants in system header files. This can be useful when preparing code to use with the @code{FLOAT_CONST_DECIMAL64} pragma from the decimal floating-point extension to C99. + +@item -Wdesignated-init @r{(C and Objective-C only)} +Issue a warning when a positional initializer is used to initialize a +structure that has been marked with the @code{designated_init} +attribute. + @end table @node Debugging Options diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 665280c..57eea75 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2014-01-20 Tom Tromey + + PR c/59855 + * gcc.dg/Wdesignated-init.c: New file. + 2014-01-19 Uros Bizjak * g++.dg/pr49718.C: Add "-mno-explicit-relocs" for alpha*-*-* targets. diff --git a/gcc/testsuite/gcc.dg/Wdesignated-init.c b/gcc/testsuite/gcc.dg/Wdesignated-init.c new file mode 100644 index 0000000..72cda8b --- /dev/null +++ b/gcc/testsuite/gcc.dg/Wdesignated-init.c @@ -0,0 +1,82 @@ +/* PR c/59855 */ +/* { dg-do compile } */ +/* { dg-options "-Wdesignated-init" } */ + +typedef int vvv __attribute__((designated_init)); /* { dg-error "only valid" } */ + +union U { + int a; + double b; +} __attribute__((designated_init)); /* { dg-error "only valid" } */ + +enum E { ONE, TWO } __attribute__((designated_init)); /* { dg-error "only valid" } */ + +struct Pok { + int x; + int y; +}; + +struct Des { + int x; + int y; +} __attribute__ ((designated_init)); + +struct Des d1 = { 5, 5 }; /* { dg-warning "(positional|near initialization)" } */ +struct Des d2 = { .x = 5, .y = 5 }; +struct Des d3 = { .x = 5, 5 }; /* { dg-warning "(positional|near initialization)" } */ + +struct Des fd1 (void) +{ + return (struct Des) { 5, 5 }; /* { dg-warning "(positional|near initialization)" } */ +} + +struct Des fd2 (void) +{ + return (struct Des) { .x = 5, .y = 5 }; +} + +struct Des fd3 (void) +{ + return (struct Des) { .x = 5, 5 }; /* { dg-warning "(positional|near initialization)" } */ +} + +struct Wrap { + struct Pok p; + struct Des d; +} __attribute__ ((designated_init)); + +struct Wrap w1 = { { 0, 1 }, { 2, 3} }; /* { dg-warning "(positional|near initialization)" } */ +struct Wrap w2 = { .p = { 0, 1 }, { 2, 3} }; /* { dg-warning "(positional|near initialization)" } */ +struct Wrap w3 = { .p = { 0, 1 }, .d = { 2, 3} }; /* { dg-warning "(positional|near initialization)" } */ +struct Wrap w4 = { { 0, 1 }, .d = { 2, 3} }; /* { dg-warning "(positional|near initialization)" } */ +struct Wrap w5 = { .p = { 0, 1 }, .d = { .x = 2, .y = 3} }; + +struct Wrap fw1 (void) +{ + return (struct Wrap) { { 0, 1 }, { 2, 3} }; /* { dg-warning "(positional|near initialization)" } */ +}; + +struct Wrap fw2 (void) +{ + return (struct Wrap) { .p = { 0, 1 }, { 2, 3} }; /* { dg-warning "(positional|near initialization)" } */ +} + +struct Wrap fw3 (void) +{ + return (struct Wrap) { .p = { 0, 1 }, .d = { 2, 3} }; /* { dg-warning "(positional|near initialization)" } */ +} + +struct Wrap fw4 (void) +{ + return (struct Wrap) { { 0, 1 }, .d = { 2, 3} }; /* { dg-warning "(positional|near initialization)" } */ +} + +struct Wrap fw5 (void) +{ + return (struct Wrap) { .p = { 0, 1 }, .d = { .x = 2, .y = 3} }; +} + +struct Des da[] = { + { .x = 1, .y = 2 }, + { 5, 5 } /* { dg-warning "(positional|near initialization)" } */ +};