From patchwork Wed Oct 16 10:13:50 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Alejandro Colomar X-Patchwork-Id: 1997954 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=IVK+oVGc; dkim-atps=neutral Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=gcc.gnu.org (client-ip=8.43.85.97; helo=server2.sourceware.org; envelope-from=gcc-patches-bounces~incoming=patchwork.ozlabs.org@gcc.gnu.org; receiver=patchwork.ozlabs.org) Received: from server2.sourceware.org (server2.sourceware.org [8.43.85.97]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (secp384r1) server-digest SHA384) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4XT6LW17drz1xv6 for ; Wed, 16 Oct 2024 21:16:03 +1100 (AEDT) Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id 4ABF53858417 for ; Wed, 16 Oct 2024 10:16:01 +0000 (GMT) X-Original-To: gcc-patches@gcc.gnu.org Delivered-To: gcc-patches@gcc.gnu.org Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by sourceware.org (Postfix) with ESMTPS id 68A3A3858288 for ; Wed, 16 Oct 2024 10:13:53 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 68A3A3858288 Authentication-Results: sourceware.org; dmarc=pass (p=quarantine dis=none) header.from=kernel.org Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=kernel.org ARC-Filter: OpenARC Filter v1.0.0 sourceware.org 68A3A3858288 Authentication-Results: server2.sourceware.org; arc=none smtp.remote-ip=139.178.84.217 ARC-Seal: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1729073638; cv=none; b=FSIuMDdUS9u97/Ms7Wek7R20yitygWjzuOc1I1WkMzxyKHhnF1Imb9Om+jf4OCU7jl9i7UgOfIsp0I7BxopjaBVyEK2+LV1OUSALckgH0kY8SVIy37Iq+PKP0XLC/lleDQ+JA0Lwzc/1bB0z9cW4ZEcnC66hPFxLq2wH/0GOMTY= ARC-Message-Signature: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1729073638; c=relaxed/simple; bh=DsjlXFnzwr9SLAwv1tsSRFHtvt1e0wHWmuvQEyaMC0M=; h=DKIM-Signature:Date:From:To:Subject:Message-ID:MIME-Version; b=N0UUibKOjm1FOoVGTDD6NOi2CWpSn7NiDL889+hv4wWPSBhrgFA/Qeefi4xXGtNrzYDvVo80E8hbRHnVdklRP/rm8CQXm7eAoFoYy0QRIdvVCCjOgAl26MQsia5UptmAlNuS0VQNxQJQi+NqW+c149sXQAX41ODexV4dJ9G8RNc= ARC-Authentication-Results: i=1; server2.sourceware.org Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by dfw.source.kernel.org (Postfix) with ESMTP id 828CB5C5B2D; Wed, 16 Oct 2024 10:13:48 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id BAB90C4CEC5; Wed, 16 Oct 2024 10:13:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1729073632; bh=DsjlXFnzwr9SLAwv1tsSRFHtvt1e0wHWmuvQEyaMC0M=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=IVK+oVGcIz56OO5ZkpUhXkco68C/oqoL4YtSxWqJIWIY3JQ1L2bOhOtu0/v5bh/G8 xPxg0WCymUMh07EchJJwT0XTpjDSJsVFzyS3uqfxpU5MDR4QoU56+CRsJng7if5kQQ d47VBNMFzYvvfY/JfbjN3Ppn9Uof5OCV2xkQx9mvKLTasw9rwUChnQLGToCwi1tH9x cTap9i/UaPHr/DYAQ/IvYKfAmqykEFOdIOBsoYZ3lqDx9emusNGplhYlddEhZwxGLm Y839AJSHFhg+65jySmBGr2pVd7JnEYtPXtGJLegO3J/P9BP2d/4O3fKRwKmkc4MC2J zgQtFryO3Cc5w== Date: Wed, 16 Oct 2024 12:13:50 +0200 From: Alejandro Colomar To: gcc-patches@gcc.gnu.org Cc: Richard Biener Subject: [PATCH v15 4/4] c: Add __countof__ operator Message-ID: <8a6959d2d382e62c1034567775988624acbffbaf.1729073399.git.alx@kernel.org> X-Mailer: git-send-email 2.45.2 References: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-Spam-Status: No, score=-10.0 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, GIT_PATCH_0, KAM_SHORT, 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: gcc-patches@gcc.gnu.org X-Mailman-Version: 2.1.30 Precedence: list List-Id: Gcc-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: gcc-patches-bounces~incoming=patchwork.ozlabs.org@gcc.gnu.org This operator is similar to sizeof but can only be applied to an array, and returns its number of elements. FUTURE DIRECTIONS: - We should make it work with array parameters to functions, and somehow magically return the number of elements of the array, regardless of it being really a pointer. - Fix support for [0]. gcc/ChangeLog: * doc/extend.texi: Document __countof__ operator. gcc/c-family/ChangeLog: * c-common.h * c-common.def * c-common.cc (c_countof_type): Add __countof__ operator. gcc/c/ChangeLog: * c-tree.h (c_expr_countof_expr, c_expr_countof_type) * c-decl.cc (start_struct, finish_struct) (start_enum, finish_enum) * c-parser.cc (c_parser_sizeof_expression) (c_parser_countof_expression) (c_parser_sizeof_or_countof_expression) (c_parser_unary_expression) * c-typeck.cc (build_external_ref) (record_maybe_used_decl) (pop_maybe_used) (is_top_array_vla) (c_expr_countof_expr, c_expr_countof_type): Add __countof__operator. gcc/testsuite/ChangeLog: * gcc.dg/countof-compile.c * gcc.dg/countof-vla.c * gcc.dg/countof.c: Add tests for __countof__ operator. Link: Link: Link: Link: Link: Link: Link: Link: Suggested-by: Xavier Del Campo Romero Co-authored-by: Martin Uecker Acked-by: "James K. Lowden" Cc: Joseph Myers Cc: Gabriel Ravier Cc: Jakub Jelinek Cc: Kees Cook Cc: Qing Zhao Cc: Jens Gustedt Cc: David Brown Cc: Florian Weimer Cc: Andreas Schwab Cc: Timm Baeder Cc: Daniel Plakosh Cc: "A. Jiang" Cc: Eugene Zelenko Cc: Aaron Ballman Cc: Paul Koning Cc: Daniel Lundin Cc: Nikolaos Strimpas Cc: JeanHeyd Meneide Cc: Fernando Borretti Cc: Jonathan Protzenko Cc: Chris Bazley Cc: Ville Voutilainen Cc: Alex Celeste Cc: Jakub Łukasiewicz Cc: Douglas McIlroy Cc: Jason Merrill Cc: "Gustavo A. R. Silva" Cc: Patrizia Kaye Cc: Ori Bernstein Cc: Robert Seacord Cc: Marek Polacek Cc: Sam James Signed-off-by: Alejandro Colomar --- gcc/c-family/c-common.cc | 26 +++++ gcc/c-family/c-common.def | 3 + gcc/c-family/c-common.h | 2 + gcc/c/c-decl.cc | 22 +++- gcc/c/c-parser.cc | 62 +++++++--- gcc/c/c-tree.h | 4 + gcc/c/c-typeck.cc | 118 ++++++++++++++++++- gcc/doc/extend.texi | 30 +++++ gcc/testsuite/gcc.dg/countof-compile.c | 115 +++++++++++++++++++ gcc/testsuite/gcc.dg/countof-vla.c | 46 ++++++++ gcc/testsuite/gcc.dg/countof.c | 150 +++++++++++++++++++++++++ 11 files changed, 554 insertions(+), 24 deletions(-) create mode 100644 gcc/testsuite/gcc.dg/countof-compile.c create mode 100644 gcc/testsuite/gcc.dg/countof-vla.c create mode 100644 gcc/testsuite/gcc.dg/countof.c diff --git a/gcc/c-family/c-common.cc b/gcc/c-family/c-common.cc index ec6a5da892d..5e374d56a87 100644 --- a/gcc/c-family/c-common.cc +++ b/gcc/c-family/c-common.cc @@ -465,6 +465,7 @@ const struct c_common_resword c_common_reswords[] = { "__inline", RID_INLINE, 0 }, { "__inline__", RID_INLINE, 0 }, { "__label__", RID_LABEL, 0 }, + { "__countof__", RID_COUNTOF, 0 }, { "__null", RID_NULL, 0 }, { "__real", RID_REALPART, 0 }, { "__real__", RID_REALPART, 0 }, @@ -4070,6 +4071,31 @@ c_alignof_expr (location_t loc, tree expr) return fold_convert_loc (loc, size_type_node, t); } + +/* Implement the countof keyword: + Return the number of elements of an array. */ + +tree +c_countof_type (location_t loc, tree type) +{ + enum tree_code type_code; + + type_code = TREE_CODE (type); + if (type_code != ARRAY_TYPE) + { + error_at (loc, "invalid application of % to type %qT", type); + return error_mark_node; + } + if (!COMPLETE_TYPE_P (type)) + { + error_at (loc, + "invalid application of % to incomplete type %qT", + type); + return error_mark_node; + } + + return array_type_nelts_top (type); +} /* Handle C and C++ default attributes. */ diff --git a/gcc/c-family/c-common.def b/gcc/c-family/c-common.def index 5de96e5d4a8..3d882e70cc0 100644 --- a/gcc/c-family/c-common.def +++ b/gcc/c-family/c-common.def @@ -50,6 +50,9 @@ DEFTREECODE (EXCESS_PRECISION_EXPR, "excess_precision_expr", tcc_expression, 1) number. */ DEFTREECODE (USERDEF_LITERAL, "userdef_literal", tcc_exceptional, 3) +/* Represents a 'countof' expression. */ +DEFTREECODE (COUNTOF_EXPR, "countof_expr", tcc_expression, 1) + /* Represents a 'sizeof' expression during C++ template expansion, or for the purpose of -Wsizeof-pointer-memaccess warning. */ DEFTREECODE (SIZEOF_EXPR, "sizeof_expr", tcc_expression, 1) diff --git a/gcc/c-family/c-common.h b/gcc/c-family/c-common.h index 027f077d51b..5d2cb158d54 100644 --- a/gcc/c-family/c-common.h +++ b/gcc/c-family/c-common.h @@ -105,6 +105,7 @@ enum rid /* C extensions */ RID_ASM, RID_TYPEOF, RID_TYPEOF_UNQUAL, RID_ALIGNOF, RID_ATTRIBUTE, + RID_COUNTOF, RID_VA_ARG, RID_EXTENSION, RID_IMAGPART, RID_REALPART, RID_LABEL, RID_CHOOSE_EXPR, RID_TYPES_COMPATIBLE_P, RID_BUILTIN_COMPLEX, RID_BUILTIN_SHUFFLE, @@ -888,6 +889,7 @@ extern tree c_common_truthvalue_conversion (location_t, tree); extern void c_apply_type_quals_to_decl (int, tree); extern tree c_sizeof_or_alignof_type (location_t, tree, bool, bool, int); extern tree c_alignof_expr (location_t, tree); +extern tree c_countof_type (location_t, tree); /* Print an error message for invalid operands to arith operation CODE. NOP_EXPR is used as a special case (see truthvalue_conversion). */ extern void binary_op_error (rich_location *, enum tree_code, tree, tree); diff --git a/gcc/c/c-decl.cc b/gcc/c/c-decl.cc index a03f756bf33..3733966d51b 100644 --- a/gcc/c/c-decl.cc +++ b/gcc/c/c-decl.cc @@ -8992,12 +8992,17 @@ start_struct (location_t loc, enum tree_code code, tree name, within a statement expr used within sizeof, et. al. This is not terribly serious as C++ doesn't permit statement exprs within sizeof anyhow. */ - if (warn_cxx_compat && (in_sizeof || in_typeof || in_alignof)) + if (warn_cxx_compat + && (in_sizeof || in_typeof || in_alignof || in_countof)) warning_at (loc, OPT_Wc___compat, "defining type in %qs expression is invalid in C++", (in_sizeof ? "sizeof" - : (in_typeof ? "typeof" : "alignof"))); + : (in_typeof + ? "typeof" + : (in_alignof + ? "alignof" + : "countof")))); if (in_underspecified_init) error_at (loc, "%qT defined in underspecified object initializer", ref); @@ -9961,7 +9966,7 @@ finish_struct (location_t loc, tree t, tree fieldlist, tree attributes, struct_types. */ if (warn_cxx_compat && struct_parse_info != NULL - && !in_sizeof && !in_typeof && !in_alignof) + && !in_sizeof && !in_typeof && !in_alignof && !in_countof) struct_parse_info->struct_types.safe_push (t); } @@ -10135,12 +10140,17 @@ start_enum (location_t loc, struct c_enum_contents *the_enum, tree name, /* FIXME: This will issue a warning for a use of a type defined within sizeof in a statement expr. This is not terribly serious as C++ doesn't permit statement exprs within sizeof anyhow. */ - if (warn_cxx_compat && (in_sizeof || in_typeof || in_alignof)) + if (warn_cxx_compat + && (in_sizeof || in_typeof || in_alignof || in_countof)) warning_at (loc, OPT_Wc___compat, "defining type in %qs expression is invalid in C++", (in_sizeof ? "sizeof" - : (in_typeof ? "typeof" : "alignof"))); + : (in_typeof + ? "typeof" + : (in_alignof + ? "alignof" + : "countof")))); if (in_underspecified_init) error_at (loc, "%qT defined in underspecified object initializer", @@ -10334,7 +10344,7 @@ finish_enum (tree enumtype, tree values, tree attributes) struct_types. */ if (warn_cxx_compat && struct_parse_info != NULL - && !in_sizeof && !in_typeof && !in_alignof) + && !in_sizeof && !in_typeof && !in_alignof && !in_countof) struct_parse_info->struct_types.safe_push (enumtype); /* Check for consistency with previous definition */ diff --git a/gcc/c/c-parser.cc b/gcc/c/c-parser.cc index fe01f955e21..ffd8d6eafe7 100644 --- a/gcc/c/c-parser.cc +++ b/gcc/c/c-parser.cc @@ -74,7 +74,17 @@ along with GCC; see the file COPYING3. If not see #include "bitmap.h" #include "analyzer/analyzer-language.h" #include "toplev.h" + +#define c_parser_sizeof_expression(parser) \ +( \ + c_parser_sizeof_or_countof_expression (parser, RID_SIZEOF) \ +) +#define c_parser_countof_expression(parser) \ +( \ + c_parser_sizeof_or_countof_expression (parser, RID_COUNTOF) \ +) + /* We need to walk over decls with incomplete struct/union/enum types after parsing the whole translation unit. In finish_decl(), if the decl is static, has incomplete @@ -1694,7 +1704,8 @@ static struct c_expr c_parser_binary_expression (c_parser *, struct c_expr *, tree); static struct c_expr c_parser_cast_expression (c_parser *, struct c_expr *); static struct c_expr c_parser_unary_expression (c_parser *); -static struct c_expr c_parser_sizeof_expression (c_parser *); +static struct c_expr c_parser_sizeof_or_countof_expression (c_parser *, + enum rid); static struct c_expr c_parser_alignof_expression (c_parser *); static struct c_expr c_parser_postfix_expression (c_parser *); static struct c_expr c_parser_postfix_expression_after_paren_type (c_parser *, @@ -9910,6 +9921,8 @@ c_parser_unary_expression (c_parser *parser) case CPP_KEYWORD: switch (c_parser_peek_token (parser)->keyword) { + case RID_COUNTOF: + return c_parser_countof_expression (parser); case RID_SIZEOF: return c_parser_sizeof_expression (parser); case RID_ALIGNOF: @@ -9949,12 +9962,13 @@ c_parser_unary_expression (c_parser *parser) /* Parse a sizeof expression. */ static struct c_expr -c_parser_sizeof_expression (c_parser *parser) +c_parser_sizeof_or_countof_expression (c_parser *parser, enum rid rid) { + const char *op_name = (rid == RID_COUNTOF) ? "countof" : "sizeof"; struct c_expr expr; struct c_expr result; location_t expr_loc; - gcc_assert (c_parser_next_token_is_keyword (parser, RID_SIZEOF)); + gcc_assert (c_parser_next_token_is_keyword (parser, rid)); location_t start; location_t finish = UNKNOWN_LOCATION; @@ -9963,7 +9977,10 @@ c_parser_sizeof_expression (c_parser *parser) c_parser_consume_token (parser); c_inhibit_evaluation_warnings++; - in_sizeof++; + if (rid == RID_COUNTOF) + in_countof++; + else + in_sizeof++; if (c_parser_next_token_is (parser, CPP_OPEN_PAREN) && c_token_starts_compound_literal (c_parser_peek_2nd_token (parser))) { @@ -9982,7 +9999,10 @@ c_parser_sizeof_expression (c_parser *parser) { struct c_expr ret; c_inhibit_evaluation_warnings--; - in_sizeof--; + if (rid == RID_COUNTOF) + in_countof--; + else + in_sizeof--; ret.set_error (); ret.original_code = ERROR_MARK; ret.original_type = NULL; @@ -9994,31 +10014,45 @@ c_parser_sizeof_expression (c_parser *parser) type_name, expr_loc); finish = expr.get_finish (); - goto sizeof_expr; + goto Xof_expr; } /* sizeof ( type-name ). */ if (scspecs) - error_at (expr_loc, "storage class specifier in %"); + error_at (expr_loc, "storage class specifier in %qs", op_name); if (type_name->specs->alignas_p) error_at (type_name->specs->locations[cdw_alignas], - "alignment specified for type name in %"); + "alignment specified for type name in %qs", op_name); c_inhibit_evaluation_warnings--; - in_sizeof--; - result = c_expr_sizeof_type (expr_loc, type_name); + if (rid == RID_COUNTOF) + { + in_countof--; + result = c_expr_countof_type (expr_loc, type_name); + } + else + { + in_sizeof--; + result = c_expr_sizeof_type (expr_loc, type_name); + } } else { expr_loc = c_parser_peek_token (parser)->location; expr = c_parser_unary_expression (parser); finish = expr.get_finish (); - sizeof_expr: + Xof_expr: c_inhibit_evaluation_warnings--; - in_sizeof--; + if (rid == RID_COUNTOF) + in_countof--; + else + in_sizeof--; mark_exp_read (expr.value); if (TREE_CODE (expr.value) == COMPONENT_REF && DECL_C_BIT_FIELD (TREE_OPERAND (expr.value, 1))) - error_at (expr_loc, "% applied to a bit-field"); - result = c_expr_sizeof_expr (expr_loc, expr); + error_at (expr_loc, "%qs applied to a bit-field", op_name); + if (rid == RID_COUNTOF) + result = c_expr_countof_expr (expr_loc, expr); + else + result = c_expr_sizeof_expr (expr_loc, expr); } if (finish == UNKNOWN_LOCATION) finish = start; diff --git a/gcc/c/c-tree.h b/gcc/c/c-tree.h index b3e7bb013b6..22d289c2db6 100644 --- a/gcc/c/c-tree.h +++ b/gcc/c/c-tree.h @@ -736,6 +736,7 @@ extern int c_type_dwarf_attribute (const_tree, int); /* in c-typeck.cc */ extern int in_alignof; extern int in_sizeof; +extern int in_countof; extern int in_typeof; extern bool c_in_omp_for; extern bool c_omp_array_section_p; @@ -786,6 +787,9 @@ extern tree build_external_ref (location_t, tree, bool, tree *); extern void pop_maybe_used (bool); extern struct c_expr c_expr_sizeof_expr (location_t, struct c_expr); extern struct c_expr c_expr_sizeof_type (location_t, struct c_type_name *); +extern struct c_expr c_expr_countof_expr (location_t, struct c_expr); +extern struct c_expr c_expr_countof_type (location_t loc, + struct c_type_name *); extern struct c_expr parser_build_unary_op (location_t, enum tree_code, struct c_expr); extern struct c_expr parser_build_binary_op (location_t, diff --git a/gcc/c/c-typeck.cc b/gcc/c/c-typeck.cc index ba6d96d26b2..ad7d71031a4 100644 --- a/gcc/c/c-typeck.cc +++ b/gcc/c/c-typeck.cc @@ -71,6 +71,9 @@ int in_alignof; /* The level of nesting inside "sizeof". */ int in_sizeof; +/* The level of nesting inside "countof". */ +int in_countof; + /* The level of nesting inside "typeof". */ int in_typeof; @@ -3258,7 +3261,7 @@ build_external_ref (location_t loc, tree id, bool fun, tree *type) if (TREE_CODE (ref) == FUNCTION_DECL && !in_alignof) { - if (!in_sizeof && !in_typeof) + if (!in_sizeof && !in_typeof && !in_countof) C_DECL_USED (ref) = 1; else if (DECL_INITIAL (ref) == NULL_TREE && DECL_EXTERNAL (ref) @@ -3314,7 +3317,7 @@ struct maybe_used_decl { /* The decl. */ tree decl; - /* The level seen at (in_sizeof + in_typeof). */ + /* The level seen at (in_sizeof + in_typeof + in_countof). */ int level; /* The next one at this level or above, or NULL. */ struct maybe_used_decl *next; @@ -3332,7 +3335,7 @@ record_maybe_used_decl (tree decl) { struct maybe_used_decl *t = XOBNEW (&parser_obstack, struct maybe_used_decl); t->decl = decl; - t->level = in_sizeof + in_typeof; + t->level = in_sizeof + in_typeof + in_countof; t->next = maybe_used_decls; maybe_used_decls = t; } @@ -3346,7 +3349,7 @@ void pop_maybe_used (bool used) { struct maybe_used_decl *p = maybe_used_decls; - int cur_level = in_sizeof + in_typeof; + int cur_level = in_sizeof + in_typeof + in_countof; while (p && p->level > cur_level) { if (used) @@ -3456,6 +3459,113 @@ c_expr_sizeof_type (location_t loc, struct c_type_name *t) return ret; } +static bool +is_top_array_vla (tree type) +{ + bool zero, star, var; + tree d; + + if (TREE_CODE (type) != ARRAY_TYPE) + return false; + if (!COMPLETE_TYPE_P (type)) + return false; + + d = TYPE_DOMAIN (type); + zero = !TYPE_MAX_VALUE (d); + star = (zero && C_TYPE_VARIABLE_SIZE (type)); + if (star) + return true; + if (zero) + return false; + + var = (TREE_CODE (TYPE_MIN_VALUE (d)) != INTEGER_CST + || TREE_CODE (TYPE_MAX_VALUE (d)) != INTEGER_CST); + return var; +} + +/* Return the result of countof applied to EXPR. */ + +struct c_expr +c_expr_countof_expr (location_t loc, struct c_expr expr) +{ + struct c_expr ret; + if (expr.value == error_mark_node) + { + ret.value = error_mark_node; + ret.original_code = ERROR_MARK; + ret.original_type = NULL; + ret.m_decimal = 0; + pop_maybe_used (false); + } + else + { + bool expr_const_operands = true; + + tree folded_expr = c_fully_fold (expr.value, require_constant_value, + &expr_const_operands); + ret.value = c_countof_type (loc, TREE_TYPE (folded_expr)); + c_last_sizeof_arg = expr.value; + c_last_sizeof_loc = loc; + ret.original_code = COUNTOF_EXPR; + ret.original_type = NULL; + ret.m_decimal = 0; + if (is_top_array_vla (TREE_TYPE (folded_expr))) + { + /* countof is evaluated when given a vla. */ + ret.value = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (ret.value), + folded_expr, ret.value); + C_MAYBE_CONST_EXPR_NON_CONST (ret.value) = !expr_const_operands; + SET_EXPR_LOCATION (ret.value, loc); + } + pop_maybe_used (is_top_array_vla (TREE_TYPE (folded_expr))); + } + return ret; +} + +/* Return the result of countof applied to T, a structure for the type + name passed to countof (rather than the type itself). LOC is the + location of the original expression. */ + +struct c_expr +c_expr_countof_type (location_t loc, struct c_type_name *t) +{ + tree type; + struct c_expr ret; + tree type_expr = NULL_TREE; + bool type_expr_const = true; + type = groktypename (t, &type_expr, &type_expr_const); + ret.value = c_countof_type (loc, type); + c_last_sizeof_arg = type; + c_last_sizeof_loc = loc; + ret.original_code = COUNTOF_EXPR; + ret.original_type = NULL; + ret.m_decimal = 0; + if (type == error_mark_node) + { + ret.value = error_mark_node; + ret.original_code = ERROR_MARK; + } + else + if ((type_expr || TREE_CODE (ret.value) == INTEGER_CST) + && is_top_array_vla (type)) + { + /* If the type is a [*] array, it is a VLA but is represented as + having a size of zero. In such a case we must ensure that + the result of countof does not get folded to a constant by + c_fully_fold, because if the number of elements is evaluated + the result is not constant and so + constraints on zero or negative size arrays must not be applied + when this countof call is inside another array declarator. */ + if (!type_expr) + type_expr = integer_zero_node; + ret.value = build2 (C_MAYBE_CONST_EXPR, TREE_TYPE (ret.value), + type_expr, ret.value); + C_MAYBE_CONST_EXPR_NON_CONST (ret.value) = !type_expr_const; + } + pop_maybe_used (type != error_mark_node ? is_top_array_vla (type) : false); + return ret; +} + /* Build a function call to function FUNCTION with parameters PARAMS. The function call is at LOC. PARAMS is a list--a chain of TREE_LIST nodes--in which the diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi index 302c3299ede..82f31668e37 100644 --- a/gcc/doc/extend.texi +++ b/gcc/doc/extend.texi @@ -10555,6 +10555,36 @@ If the operand of the @code{__alignof__} expression is a function, the expression evaluates to the alignment of the function which may be specified by attribute @code{aligned} (@pxref{Common Function Attributes}). +@node countof +@section Determining the Number of Elements of Arrays +@cindex countof +@cindex number of elements + +The keyword @code{__countof__} determines +the number of elements of an array operand. +Its syntax is similar to @code{sizeof}. +The operand must be +a parenthesized complete array type name +or an expression of such a type. +For example: + +@smallexample +int a[n]; +__countof__ (a); // returns n +__countof__ (int [7][3]); // returns 7 +@end smallexample + +The result of this operator is an integer constant expression, +unless the array has a variable number of elements. +The operand is only evaluated +if the array has a variable number of elements. +For example: + +@smallexample +__countof__ (int [7][n++]); // integer constant expression +__countof__ (int [n++][7]); // run-time value; n++ is evaluated +@end smallexample + @node Inline @section An Inline Function is As Fast As a Macro @cindex inline functions diff --git a/gcc/testsuite/gcc.dg/countof-compile.c b/gcc/testsuite/gcc.dg/countof-compile.c new file mode 100644 index 00000000000..6e2592edbb0 --- /dev/null +++ b/gcc/testsuite/gcc.dg/countof-compile.c @@ -0,0 +1,115 @@ +/* { dg-do compile } */ +/* { dg-options "-Wno-declaration-after-statement -Wno-pedantic -Wno-vla" } */ + +extern int x[]; + +static int w[] = {1, 2, 3}; + +static int z[0]; +static int y[__countof__(z)]; + +void +automatic(void) +{ + __countof__ (w); +} + +void +incomplete (int p[]) +{ + __countof__ (x); /* { dg-error "incomplete" } */ + + /* We want to support the following one in the future, + but for now it should fail. */ + __countof__ (p); /* { dg-error "invalid" } */ +} + +void +fam (void) +{ + struct { + int x; + int fam[]; + } s; + + __countof__ (s.fam); /* { dg-error "incomplete" } */ +} + +void fix_fix (int i, char (*a)[3][5], int (*x)[__countof__ (*a)]); +void fix_var (int i, char (*a)[3][i], int (*x)[__countof__ (*a)]); +void fix_uns (int i, char (*a)[3][*], int (*x)[__countof__ (*a)]); + +void +func (void) +{ + int i3[3]; + int i5[5]; + char c35[3][5]; + + fix_fix (5, &c35, &i3); + fix_fix (5, &c35, &i5); /* { dg-error "incompatible-pointer-types" } */ + + fix_var (5, &c35, &i3); + fix_var (5, &c35, &i5); /* { dg-error "incompatible-pointer-types" } */ + + fix_uns (5, &c35, &i3); + fix_uns (5, &c35, &i5); /* { dg-error "incompatible-pointer-types" } */ +} + +void +non_arr(void) +{ + int x; + int *p; + struct s { + int x[3]; + } s; + + __countof__ (x); /* { dg-error "invalid" } */ + __countof__ (int); /* { dg-error "invalid" } */ + __countof__ (s); /* { dg-error "invalid" } */ + __countof__ (struct s); /* { dg-error "invalid" } */ + __countof__ (&x); /* { dg-error "invalid" } */ + __countof__ (p); /* { dg-error "invalid" } */ + __countof__ (int *); /* { dg-error "invalid" } */ + __countof__ (&s.x); /* { dg-error "invalid" } */ + __countof__ (int (*)[3]); /* { dg-error "invalid" } */ +} + +static int f1(); +static int f2(); /* { dg-warning "never defined" } */ +int a[10][10]; +int n; + +void +syms(void) +{ + int b[n][n]; + + __countof__ (a[f1()]); + __countof__ (b[f2()]); +} + +void +no_parens(void) +{ + __countof__ a; + __countof__ *a; + __countof__ (int [3]) {}; + + __countof__ int [3]; /* { dg-error "expected expression before" } */ +} + +void +const_expr(void) +{ + int n = 7; + + _Static_assert (__countof__ (int [3][n]) == 3); + _Static_assert (__countof__ (int [n][3]) == 7); /* { dg-error "not constant" } */ + _Static_assert (__countof__ (int [0][3]) == 0); + _Static_assert (__countof__ (int [0]) == 0); + + /* FIXME: countof(int [0][n]) should result in a constant expression. */ + _Static_assert (__countof__ (int [0][n]) == 0); /* { dg-error "not constant" } */ +} diff --git a/gcc/testsuite/gcc.dg/countof-vla.c b/gcc/testsuite/gcc.dg/countof-vla.c new file mode 100644 index 00000000000..5a82aeed782 --- /dev/null +++ b/gcc/testsuite/gcc.dg/countof-vla.c @@ -0,0 +1,46 @@ +/* { dg-do compile } */ +/* { dg-options "-Wno-pedantic -Wvla-parameter" } */ + +void fix_fix (int i, + char (*a)[3][5], + int (*x)[__countof__ (*a)]); +void fix_var (int i, + char (*a)[3][i], /* dg-warn "variable" */ + int (*x)[__countof__ (*a)]); +void fix_uns (int i, + char (*a)[3][*], + int (*x)[__countof__ (*a)]); + +void zro_fix (int i, + char (*a)[0][5], + int (*x)[__countof__ (*a)]); +void zro_var (int i, + char (*a)[0][i], /* dg-warn "variable" */ + int (*x)[__countof__ (*a)]); +void zro_uns (int i, + char (*a)[0][*], + int (*x)[__countof__ (*a)]); + +void var_fix (int i, + char (*a)[i][5], /* dg-warn "variable" */ + int (*x)[__countof__ (*a)]); /* dg-warn "variable" */ +void var_var (int i, + char (*a)[i][i], /* dg-warn "variable" */ + int (*x)[__countof__ (*a)]); /* dg-warn "variable" */ +void var_uns (int i, + char (*a)[i][*], /* dg-warn "variable" */ + int (*x)[__countof__ (*a)]); /* dg-warn "variable" */ + +void uns_fix (int i, + char (*a)[*][5], + int (*x)[__countof__ (*a)]); +void uns_var (int i, + char (*a)[*][i], /* dg-warn "variable" */ + int (*x)[__countof__ (*a)]); +void uns_uns (int i, + char (*a)[*][*], + int (*x)[__countof__ (*a)]); + +// Can't test due to bug: +//static int z2[0]; +//static int y2[__countof__(z2)]; diff --git a/gcc/testsuite/gcc.dg/countof.c b/gcc/testsuite/gcc.dg/countof.c new file mode 100644 index 00000000000..063a207fb6b --- /dev/null +++ b/gcc/testsuite/gcc.dg/countof.c @@ -0,0 +1,150 @@ +/* { dg-do run } */ +/* { dg-options "-Wno-declaration-after-statement -Wno-pedantic -Wno-vla" } */ + +#undef NDEBUG +#include + +void +array (void) +{ + short a[7]; + + static_assert (__countof__ (a) == 7); + static_assert (__countof__ (long [0]) == 0); + static_assert (__countof__ (unsigned [99]) == 99); +} + +void +automatic(void) +{ + int a[] = {1, 2, 3}; + int z[] = {}; + + static_assert (__countof__ (a) == 3); + static_assert (__countof__ (z) == 0); +} + +void +vla (void) +{ + unsigned n; + + n = 99; + assert (__countof__ (short [n - 10]) == 99 - 10); + + int v[n / 2]; + assert (__countof__ (v) == 99 / 2); + + n = 0; + int z[n]; + assert (__countof__ (z) == 0); +} + +void +member (void) +{ + struct { + int a[8]; + } s; + + static_assert (__countof__ (s.a) == 8); +} + +void +vla_eval (void) +{ + int i; + + i = 7; + assert (__countof__ (struct {int x;}[i++]) == 7); + assert (i == 7 + 1); + + int v[i]; + int (*p)[i]; + p = &v; + assert (__countof__ (*p++) == i); + assert (p - 1 == &v); +} + +void +inner_vla_noeval (void) +{ + int i; + + i = 3; + static_assert (__countof__ (struct {int x[i++];}[3]) == 3); + assert (i == 3); +} + +void +array_noeval (void) +{ + long a[5]; + long (*p)[__countof__ (a)]; + + p = &a; + static_assert (__countof__ (*p++) == 5); + assert (p == &a); +} + +void +matrix_zero (void) +{ + int i; + + static_assert (__countof__ (int [0][4]) == 0); + i = 3; + assert (__countof__ (int [0][i]) == 0); +} + +void +matrix_fixed (void) +{ + int i; + + static_assert (__countof__ (int [7][4]) == 7); + i = 3; + static_assert (__countof__ (int [7][i]) == 7); +} + +void +matrix_vla (void) +{ + int i, j; + + i = 7; + assert (__countof__ (int [i++][4]) == 7); + assert (i == 7 + 1); + + i = 9; + j = 3; + assert (__countof__ (int [i++][j]) == 9); + assert (i == 9 + 1); +} + +void +no_parens(void) +{ + int n = 3; + int a[7]; + int v[n]; + + static_assert (__countof__ a == 7); + assert (__countof__ v == 3); +} + +int +main (void) +{ + array (); + automatic (); + vla (); + member (); + vla_eval (); + inner_vla_noeval (); + array_noeval (); + matrix_zero (); + matrix_fixed (); + matrix_vla (); + no_parens (); +}