From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.9]) by sourceware.org (Postfix) with ESMTPS id EB2F33858D33 for ; Sun, 5 May 2024 18:15:30 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org EB2F33858D33 Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=linux.intel.com Authentication-Results: sourceware.org; spf=none smtp.mailfrom=linux.intel.com ARC-Filter: OpenARC Filter v1.0.0 sourceware.org EB2F33858D33 Authentication-Results: server2.sourceware.org; arc=none smtp.remote-ip=192.198.163.9 ARC-Seal: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1714932933; cv=none; b=FuyROEtG2NNuA8MOG3/q0mVlHEmVs8wDbLIGfJ/iEFe1Aer+L1ZUdM5tYc38LWN3z0Gpynnk0IEVFPEXMUb1hl/wVynmNI1fOgNrW3e8RZqhKkxKgp8j11HcfSwqkvTegUIXnqbynRh36AauP0AOWaU1Q+7AKl3Bn3wa9uJMsPk= ARC-Message-Signature: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1714932933; c=relaxed/simple; bh=K8LRpn7LAsMF8xNOf+FbJs8s+Tcn2K/OZjtJgnczO9Y=; h=DKIM-Signature:From:To:Subject:Date:Message-ID:MIME-Version; b=fWhbwgZcmhHVZvq9zb3WevJ1PKnPpcvKrAnX0m1Fri2gy6EtuiiF8raU6T/NGVwfuOHc36AXn+PkLwHunNMZ4ga8ZjbasAyvz7BE/GmbnRdXdhhd/T3A67Smb2VBw9Y1NXFxwLZ2Al7wlGDtOEDi7OzFzVGLPrIW74mwa2OQsdA= ARC-Authentication-Results: i=1; server2.sourceware.org DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1714932931; x=1746468931; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=K8LRpn7LAsMF8xNOf+FbJs8s+Tcn2K/OZjtJgnczO9Y=; b=fAQBJnZjUx2tEOjF1GxW62jLfmgrY0jEj1KZjaYNtdLSkPLdiey4WgSF SUUFeKTr1CC1tEWfL/nJFZ7KfKT3SqSdKIAge9MYLpEaULXd3tQcOOf+Y DO5rIGP4ZpRetibiu5nYi3E9rJnYHOGx3IQJ9uzjXPnErcTCfeDN8uLFw BiwZj7/mCuHHTGLUz1x/o4MBbUi2+3P1h+5z5b5j2Qxmw0nueP6Xb5BsV h75EaXx8uU/UkNcpqdZhVxm17OFjMGBNAi78X24fPtdDXxokqoSGJdp5D k8sMSbjH8xIGw7osJkzjgyTPklkKOtpz0ZedFXtWmtoIZESw+nFGJy1kf w==; X-CSE-ConnectionGUID: GI9ddjb9SvqOvGIhc00rYg== X-CSE-MsgGUID: p0pBewd6QhaRTLn1ID6x2w== X-IronPort-AV: E=McAfee;i="6600,9927,11064"; a="21356323" X-IronPort-AV: E=Sophos;i="6.07,256,1708416000"; d="scan'208";a="21356323" Received: from orviesa007.jf.intel.com ([10.64.159.147]) by fmvoesa103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 05 May 2024 11:15:26 -0700 X-CSE-ConnectionGUID: qWrv4Z7bS2ioHpmLqe8szw== X-CSE-MsgGUID: FVhBEtXPTR6iy9ZGl8zKnw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.07,256,1708416000"; d="scan'208";a="28457580" Received: from tassilo.jf.intel.com ([10.54.38.190]) by orviesa007-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 05 May 2024 11:15:25 -0700 From: Andi Kleen To: gcc-patches@gcc.gnu.org Cc: nathan@acm.org, josmyers@redhat.com, richard.sandiford@arm.com, jason@redhat.com, Andi Kleen Subject: [PATCH v5 3/5] C: Implement musttail attribute for returns Date: Sun, 5 May 2024 11:14:56 -0700 Message-ID: <20240505181458.2903045-3-ak@linux.intel.com> X-Mailer: git-send-email 2.44.0 In-Reply-To: <20240505181458.2903045-1-ak@linux.intel.com> References: <20240505181458.2903045-1-ak@linux.intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Spam-Status: No, score=-11.3 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_EF,GIT_PATCH_0,SPF_HELO_NONE,SPF_NONE,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 List-Id: Implement a C23 clang compatible musttail attribute similar to the earlier C++ implementation in the C parser. PR83324 gcc/c/ChangeLog: * c-parser.cc (struct attr_state): Define with musttail_p. (c_parser_statement_after_labels): Handle [[musttail]] (c_parser_std_attribute): Dito. (c_parser_handle_musttail): Dito. (c_parser_compound_statement_nostart): Dito. (c_parser_all_labels): Dito. (c_parser_statement): Dito. * c-tree.h (c_finish_return): Add musttail_p flag. * c-typeck.cc (c_finish_return): Handle musttail_p flag. --- gcc/c/c-parser.cc | 61 +++++++++++++++++++++++++++++++++++++---------- gcc/c/c-tree.h | 2 +- gcc/c/c-typeck.cc | 15 ++++++++++-- 3 files changed, 63 insertions(+), 15 deletions(-) diff --git a/gcc/c/c-parser.cc b/gcc/c/c-parser.cc index 00f8bf4376e5..9edadb0fee96 100644 --- a/gcc/c/c-parser.cc +++ b/gcc/c/c-parser.cc @@ -1616,6 +1616,11 @@ struct omp_for_parse_data { bool fail : 1; }; +struct attr_state +{ + bool musttail_p; // parsed a musttail for return +}; + static bool c_parser_nth_token_starts_std_attributes (c_parser *, unsigned int); static tree c_parser_std_attribute_specifier_sequence (c_parser *); @@ -1660,7 +1665,7 @@ static location_t c_parser_compound_statement_nostart (c_parser *); static void c_parser_label (c_parser *, tree); static void c_parser_statement (c_parser *, bool *, location_t * = NULL); static void c_parser_statement_after_labels (c_parser *, bool *, - vec * = NULL); + vec * = NULL, attr_state = {}); static tree c_parser_c99_block_statement (c_parser *, bool *, location_t * = NULL); static void c_parser_if_statement (c_parser *, bool *, vec *); @@ -5756,6 +5761,8 @@ c_parser_std_attribute (c_parser *parser, bool for_tm) } goto out; } + else if (is_attribute_p ("musttail", name)) + error ("% attribute has arguments"); { location_t open_loc = c_parser_peek_token (parser)->location; matching_parens parens; @@ -6941,6 +6948,28 @@ c_parser_handle_directive_omp_attributes (tree &attrs, } } +/* Check if STD_ATTR contains a musttail attribute and handle it + PARSER is the parser and A is the output attr_state. */ + +static tree +c_parser_handle_musttail (c_parser *parser, tree std_attrs, attr_state &a) +{ + if (c_parser_next_token_is_keyword (parser, RID_RETURN)) + { + if (lookup_attribute ("gnu", "musttail", std_attrs)) + { + std_attrs = remove_attribute ("gnu", "musttail", std_attrs); + a.musttail_p = true; + } + if (lookup_attribute ("clang", "musttail", std_attrs)) + { + std_attrs = remove_attribute ("clang", "musttail", std_attrs); + a.musttail_p = true; + } + } + return std_attrs; +} + /* Parse a compound statement except for the opening brace. This is used for parsing both compound statements and statement expressions (which follow different paths to handling the opening). */ @@ -6957,6 +6986,7 @@ c_parser_compound_statement_nostart (c_parser *parser) bool in_omp_loop_block = omp_for_parse_state ? omp_for_parse_state->want_nested_loop : false; tree sl = NULL_TREE; + attr_state a = {}; if (c_parser_next_token_is (parser, CPP_CLOSE_BRACE)) { @@ -7095,7 +7125,10 @@ c_parser_compound_statement_nostart (c_parser *parser) = c_parser_nth_token_starts_std_attributes (parser, 1); tree std_attrs = NULL_TREE; if (have_std_attrs) - std_attrs = c_parser_std_attribute_specifier_sequence (parser); + { + std_attrs = c_parser_std_attribute_specifier_sequence (parser); + std_attrs = c_parser_handle_musttail (parser, std_attrs, a); + } if (c_parser_next_token_is_keyword (parser, RID_CASE) || c_parser_next_token_is_keyword (parser, RID_DEFAULT) || (c_parser_next_token_is (parser, CPP_NAME) @@ -7243,7 +7276,7 @@ c_parser_compound_statement_nostart (c_parser *parser) last_stmt = true; mark_valid_location_for_stdc_pragma (false); if (!omp_for_parse_state) - c_parser_statement_after_labels (parser, NULL); + c_parser_statement_after_labels (parser, NULL, NULL, a); else { /* In canonical loop nest form, nested loops can only appear @@ -7285,15 +7318,18 @@ c_parser_compound_statement_nostart (c_parser *parser) /* Parse all consecutive labels, possibly preceded by standard attributes. In this context, a statement is required, not a declaration, so attributes must be followed by a statement that is - not just a semicolon. */ + not just a semicolon. Returns an attr_state. */ -static void +static attr_state c_parser_all_labels (c_parser *parser) { + attr_state a = {}; bool have_std_attrs; tree std_attrs = NULL; if ((have_std_attrs = c_parser_nth_token_starts_std_attributes (parser, 1))) - std_attrs = c_parser_std_attribute_specifier_sequence (parser); + std_attrs = c_parser_handle_musttail (parser, + c_parser_std_attribute_specifier_sequence (parser), a); + while (c_parser_next_token_is_keyword (parser, RID_CASE) || c_parser_next_token_is_keyword (parser, RID_DEFAULT) || (c_parser_next_token_is (parser, CPP_NAME) @@ -7315,6 +7351,7 @@ c_parser_all_labels (c_parser *parser) } else if (have_std_attrs && c_parser_next_token_is (parser, CPP_SEMICOLON)) c_parser_error (parser, "expected statement"); + return a; } /* Parse a label (C90 6.6.1, C99 6.8.1, C11 6.8.1). @@ -7558,11 +7595,11 @@ c_parser_label (c_parser *parser, tree std_attrs) static void c_parser_statement (c_parser *parser, bool *if_p, location_t *loc_after_labels) { - c_parser_all_labels (parser); + attr_state a = c_parser_all_labels (parser); if (loc_after_labels) *loc_after_labels = c_parser_peek_token (parser)->location; parser->omp_attrs_forbidden_p = false; - c_parser_statement_after_labels (parser, if_p, NULL); + c_parser_statement_after_labels (parser, if_p, NULL, a); } /* Parse a statement, other than a labeled statement. CHAIN is a vector @@ -7571,11 +7608,11 @@ c_parser_statement (c_parser *parser, bool *if_p, location_t *loc_after_labels) IF_P is used to track whether there's a (possibly labeled) if statement which is not enclosed in braces and has an else clause. This is used to - implement -Wparentheses. */ + implement -Wparentheses. A has an earlier parsed attribute state. */ static void c_parser_statement_after_labels (c_parser *parser, bool *if_p, - vec *chain) + vec *chain, attr_state a) { location_t loc = c_parser_peek_token (parser)->location; tree stmt = NULL_TREE; @@ -7643,7 +7680,7 @@ c_parser_statement_after_labels (c_parser *parser, bool *if_p, c_parser_consume_token (parser); if (c_parser_next_token_is (parser, CPP_SEMICOLON)) { - stmt = c_finish_return (loc, NULL_TREE, NULL_TREE); + stmt = c_finish_return (loc, NULL_TREE, NULL_TREE, a.musttail_p); c_parser_consume_token (parser); } else @@ -7652,7 +7689,7 @@ c_parser_statement_after_labels (c_parser *parser, bool *if_p, struct c_expr expr = c_parser_expression_conv (parser); mark_exp_read (expr.value); stmt = c_finish_return (EXPR_LOC_OR_LOC (expr.value, xloc), - expr.value, expr.original_type); + expr.value, expr.original_type, a.musttail_p); goto expect_semicolon; } break; diff --git a/gcc/c/c-tree.h b/gcc/c/c-tree.h index 22b0009874b5..002351bb9934 100644 --- a/gcc/c/c-tree.h +++ b/gcc/c/c-tree.h @@ -826,7 +826,7 @@ extern tree c_begin_stmt_expr (void); extern tree c_finish_stmt_expr (location_t, tree); extern tree c_process_expr_stmt (location_t, tree); extern tree c_finish_expr_stmt (location_t, tree); -extern tree c_finish_return (location_t, tree, tree); +extern tree c_finish_return (location_t, tree, tree, bool = false); 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, c_expr val); diff --git a/gcc/c/c-typeck.cc b/gcc/c/c-typeck.cc index 4567b114734b..174348e96d7f 100644 --- a/gcc/c/c-typeck.cc +++ b/gcc/c/c-typeck.cc @@ -11445,10 +11445,10 @@ c_finish_goto_ptr (location_t loc, c_expr val) to return, or a null pointer for `return;' with no value. LOC is the location of the return statement, or the location of the expression, if the statement has any. If ORIGTYPE is not NULL_TREE, it - is the original type of RETVAL. */ + is the original type of RETVAL. MUSTTAIL_P indicates a musttail attribute. */ tree -c_finish_return (location_t loc, tree retval, tree origtype) +c_finish_return (location_t loc, tree retval, tree origtype, bool musttail_p) { tree valtype = TREE_TYPE (TREE_TYPE (current_function_decl)), ret_stmt; bool no_warning = false; @@ -11462,6 +11462,17 @@ c_finish_return (location_t loc, tree retval, tree origtype) warning_at (xloc, 0, "function declared % has a % statement"); + if (retval && musttail_p) + { + tree t = retval; + if (TREE_CODE (t) == TARGET_EXPR) + t = TARGET_EXPR_INITIAL (t); + if (TREE_CODE (t) != CALL_EXPR) + error_at (xloc, "cannot tail-call: return value must be call"); + else + CALL_EXPR_MUST_TAIL_CALL (t) = 1; + } + if (retval) { tree semantic_type = NULL_TREE; -- 2.44.0