RFA: implement C11 _Generic

Message ID	87mx2l9emz.fsf@fleche.redhat.com
State	New
Headers	show Return-Path: <gcc-patches-return-323392-incoming=patchwork.ozlabs.org@gcc.gnu.org> Comment: DKIM? See http://www.dkim.org Comment: DomainKeys? See http://antispam.yahoo.com/domainkeys DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=default; d=gcc.gnu.org; h=Received:Received:X-SWARE-Spam-Status:X-Spam-Check-By:Received:Received:Received:From:To:Subject:Date:Message-ID:User-Agent:MIME-Version:Content-Type:Mailing-List:Precedence:List-Id:List-Unsubscribe:List-Archive:List-Post:List-Help:Sender:Delivered-To; b=PiM4SkSGjZ9KCmQY77vbMcxXlgtVeyohpglnJZKK5asN9LlGALTYL2wTjxoonF 6lOisYHngQHLT2mlHVmA0bRbeJLuhqpHtZVbUz4O1Y8OJg9SAAhVg2cyKH0J+Ga3 tMTo5VGkvLwU5XVb5a/1FHyDVZsE+uGQOeScpAf6P6jvY=; From: Tom Tromey <tromey@redhat.com> To: gcc-patches@gcc.gnu.org Subject: RFA: implement C11 _Generic Date: Fri, 27 Jul 2012 13:40:20 -0600 Message-ID: <87mx2l9emz.fsf@fleche.redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain Mailing-List: contact gcc-patches-help@gcc.gnu.org; run by ezmlm Precedence: bulk Sender: gcc-patches-owner@gcc.gnu.org

diff --git a/gcc/c-family/c-common.c b/gcc/c-family/c-common.c index b72506b..cc880de 100644 --- a/gcc/c-family/c-common.c +++ b/gcc/c-family/c-common.c @@ -418,6 +418,7 @@ const struct c_common_resword c_common_reswords[] = { "_Sat", RID_SAT, D_CONLY | D_EXT }, { "_Static_assert", RID_STATIC_ASSERT, D_CONLY }, { "_Noreturn", RID_NORETURN, D_CONLY }, + { "_Generic", RID_GENERIC, D_CONLY }, { "__FUNCTION__", RID_FUNCTION_NAME, 0 }, { "__PRETTY_FUNCTION__", RID_PRETTY_FUNCTION_NAME, 0 }, { "__alignof", RID_ALIGNOF, 0 }, diff --git a/gcc/c-family/c-common.h b/gcc/c-family/c-common.h index 050112e..415b6e0 100644 --- a/gcc/c-family/c-common.h +++ b/gcc/c-family/c-common.h @@ -1,6 +1,6 @@ /* Definitions for c-common.c. Copyright (C) 1987, 1993, 1994, 1995, 1997, 1998, - 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2007, 2008, 2009, 2010, 2011 + 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2007, 2008, 2009, 2010, 2011, 2012 Free Software Foundation, Inc. This file is part of GCC. @@ -108,7 +108,7 @@ enum rid RID_FRACT, RID_ACCUM, /* C11 */ - RID_ALIGNAS, + RID_ALIGNAS, RID_GENERIC, /* This means to warn that this is a C++ keyword, and then treat it as a normal identifier. */ diff --git a/gcc/c/c-parser.c b/gcc/c/c-parser.c index 2237749..360cc58 100644 --- a/gcc/c/c-parser.c +++ b/gcc/c/c-parser.c @@ -6158,6 +6158,195 @@ c_parser_get_builtin_args (c_parser *parser, const char *bname, return true; } +/* This represents a single generic-association. */ + +struct c_generic_association +{ + /* The location of the starting token of the type. */ + location_t type_location; + /* The association's type, or NULL_TREE for 'default'.. */ + tree type; + /* The association's expression. */ + struct c_expr expression; +}; + +typedef struct c_generic_association c_generic_association_d; + +DEF_VEC_O (c_generic_association_d); +DEF_VEC_ALLOC_O (c_generic_association_d, heap); + +/* Parse a generic-selection. (C11 6.5.1.1). + + generic-selection: + _Generic ( assignment-expression , generic-assoc-list ) + + generic-assoc-list: + generic-association + generic-assoc-list , generic-association + + generic-association: + type-name : assignment-expression + default : assignment-expression +*/ + +static struct c_expr +c_parser_generic_selection (c_parser *parser) +{ + VEC (c_generic_association_d, heap) *associations = NULL; + struct c_expr selector, error_expr; + tree selector_type; + struct c_generic_association matched_assoc; + int match_found = 0; + location_t generic_loc, selector_loc; + + error_expr.original_code = ERROR_MARK; + error_expr.original_type = NULL; + error_expr.value = error_mark_node; + + gcc_assert (c_parser_next_token_is_keyword (parser, RID_GENERIC)); + generic_loc = c_parser_peek_token (parser)->location; + c_parser_consume_token (parser); + if (!flag_isoc11) + { + if (flag_isoc99) + pedwarn (generic_loc, OPT_Wpedantic, + "ISO C99 does not support %<_Generic%>"); + else + pedwarn (generic_loc, OPT_Wpedantic, + "ISO C90 does not support %<_Generic%>"); + } + + if (!c_parser_require (parser, CPP_OPEN_PAREN, "expected %<.%>")) + return error_expr; + + c_inhibit_evaluation_warnings++; + selector_loc = c_parser_peek_token (parser)->location; + selector = c_parser_expr_no_commas (parser, NULL); + c_inhibit_evaluation_warnings--; + + if (selector.value == error_mark_node) + return selector; + mark_exp_read (selector.value); + selector_type = TREE_TYPE (selector.value); + + if (!c_parser_require (parser, CPP_COMMA, "expected %<.%>")) + return error_expr; + + while (1) + { + struct c_generic_association assoc, *iter; + int ix; + c_token *token = c_parser_peek_token (parser); + + assoc.type_location = token->location; + if (token->type == CPP_KEYWORD && token->keyword == RID_DEFAULT) + { + c_parser_consume_token (parser); + assoc.type = NULL_TREE; + } + else + { + struct c_type_name *type_name; + + type_name = c_parser_type_name (parser); + if (type_name == NULL) + goto error_exit; + assoc.type = groktypename (type_name, NULL, NULL); + if (assoc.type == error_mark_node) + goto error_exit; + + if (! COMPLETE_TYPE_P (assoc.type)) + error_at (assoc.type_location, + "%<_Generic%> association has incomplete type"); + + if (variably_modified_type_p (assoc.type, NULL_TREE)) + error_at (assoc.type_location, + "%<_Generic%> association has " + "variable length type"); + } + + if (!c_parser_require (parser, CPP_COLON, "expected %<.%>")) + goto error_exit; + + assoc.expression = c_parser_expr_no_commas (parser, NULL); + if (assoc.expression.value == error_mark_node) + goto error_exit; + + for (ix = 0; + VEC_iterate (c_generic_association_d, associations, ix, iter); + ++ix) + { + if (assoc.type == NULL_TREE) + { + if (iter->type == NULL_TREE) + { + error_at (assoc.type_location, + "duplicate %<default%> case in %<_Generic%>"); + inform (iter->type_location, "original %<default%> is here"); + } + } + else if (iter->type != NULL_TREE) + { + if (comptypes (assoc.type, iter->type)) + { + error_at (assoc.type_location, + "%<_Generic%> specifies two compatible types"); + inform (iter->type_location, "compatible type is here"); + } + } + } + + if (assoc.type == NULL_TREE) + { + if (!match_found) + { + matched_assoc = assoc; + match_found = 1; + } + } + else if (comptypes (assoc.type, selector_type)) + { + if (!match_found || matched_assoc.type == NULL_TREE) + { + matched_assoc = assoc; + match_found = 1; + } + else + { + error_at (assoc.type_location, + "%<_Generic> selector matches multiple associations"); + inform (matched_assoc.type_location, + "other match is here"); + } + } + + VEC_safe_push (c_generic_association_d, heap, associations, &assoc); + + if (c_parser_peek_token (parser)->type != CPP_COMMA) + break; + c_parser_consume_token (parser); + } + + VEC_free (c_generic_association_d, heap, associations); + + if (!c_parser_require (parser, CPP_CLOSE_PAREN, "expected %<.%>")) + return error_expr; + + if (!match_found) + { + error_at (selector_loc, "%<_Generic%> selector of type %qT is not " + "compatible with any association", + selector_type); + return error_expr; + } + + mark_exp_read (matched_assoc.expression.value); + return matched_assoc.expression; + + error_exit: + VEC_free (c_generic_association_d, heap, associations); + return error_expr; +} /* Parse a postfix expression (C90 6.3.1-6.3.2, C99 6.5.1-6.5.2). @@ -6181,6 +6370,7 @@ c_parser_get_builtin_args (c_parser *parser, const char *bname, constant string-literal ( expression ) + generic-selection GNU extensions: @@ -6749,6 +6939,9 @@ c_parser_postfix_expression (c_parser *parser) expr.value = objc_build_encode_expr (type); } break; + case RID_GENERIC: + expr = c_parser_generic_selection (parser); + break; default: c_parser_error (parser, "expected expression"); expr.value = error_mark_node; diff --git a/gcc/testsuite/gcc.dg/c11-generic-1.c b/gcc/testsuite/gcc.dg/c11-generic-1.c new file mode 100644 index 0000000..156d3a6 --- /dev/null +++ b/gcc/testsuite/gcc.dg/c11-generic-1.c @@ -0,0 +1,28 @@ +/* Test C11 _Generic. Valid uses. */ +/* { dg-do run } */ +/* { dg-options "-std=c11 -pedantic-errors" } */ + +extern void exit (int); +extern void abort (void); + +void +check (int n) +{ + if (n) + abort (); +} + +int +main (void) +{ + int n = 0; + + check (_Generic (n++, int: 0)); + /* _Generic should not evaluate its argument. */ + check (n); + + check (_Generic (n, double: n++, default: 0)); + check (n); + + exit (0); +} diff --git a/gcc/testsuite/gcc.dg/c11-generic-2.c b/gcc/testsuite/gcc.dg/c11-generic-2.c new file mode 100644 index 0000000..db06a8e --- /dev/null +++ b/gcc/testsuite/gcc.dg/c11-generic-2.c @@ -0,0 +1,24 @@ +/* Test C11 _Generic. Error cases. */ +/* { dg-do compile } */ +/* { dg-options "-std=c11 -pedantic-errors" } */ + +struct incomplete; + +void +f (int n) +{ + /* Multiple 'default's. */ + _Generic (n, default: 1, default: 2); /* { dg-error "duplicate .*default.* case" } */ + + /* Variably-modified type not ok. */ + _Generic (n, int[n]: 0, default: 1); /* { dg-error "variable length type" } */ + /* Type must be complete. */ + _Generic (n, struct incomplete: 0, default: 1); /* { dg-error "incomplete type" } */ + _Generic (n, void: 0, default: 1); /* { dg-error "incomplete type" } */ + + /* Two compatible types in association list. */ + _Generic (&n, int: 5, signed int: 7, default: 23); /* { dg-error "two compatible types" } */ + + /* No matching association. */ + _Generic (n, void *: 5); /* { dg-error "not compatible with any association" } */ +}

RFA: implement C11 _Generic

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