From mboxrd@z Thu Jan 1 00:00:00 1970 From: Luc Van Oostenryck Subject: [PATCH 4/5] C11: teach sparse about '_Alignas()' Date: Thu, 5 Jan 2017 04:22:19 +0100 Message-ID: <20170105032220.7339-5-luc.vanoostenryck@gmail.com> References: <20170105032220.7339-1-luc.vanoostenryck@gmail.com> Return-path: Received: from mail-wm0-f65.google.com ([74.125.82.65]:33934 "EHLO mail-wm0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S937571AbdAED3j (ORCPT ); Wed, 4 Jan 2017 22:29:39 -0500 Received: by mail-wm0-f65.google.com with SMTP id c85so56117682wmi.1 for ; Wed, 04 Jan 2017 19:29:38 -0800 (PST) In-Reply-To: <20170105032220.7339-1-luc.vanoostenryck@gmail.com> Sender: linux-sparse-owner@vger.kernel.org List-Id: linux-sparse@vger.kernel.org To: linux-sparse@vger.kernel.org Cc: Luc Van Oostenryck This is quite similar to GCC's 'attribute(aligned(..))' but defined as a new specifier and also accepting a typename as argument. Signed-off-by: Luc Van Oostenryck --- parse.c | 43 +++++++++++++++++++++++++++++++++++++++++++ validation/c11-alignas.c | 40 ++++++++++++++++++++++++++++++++++++++++ 2 files changed, 83 insertions(+) create mode 100644 validation/c11-alignas.c diff --git a/parse.c b/parse.c index f131d0e6..6eca5686 100644 --- a/parse.c +++ b/parse.c @@ -128,6 +128,12 @@ static struct symbol_op noreturn_op = { .declarator = noreturn_specifier, }; +static declarator_t alignas_specifier; +static struct symbol_op alignas_op = { + .type = KW_MODIFIER, + .declarator = alignas_specifier, +}; + static struct symbol_op auto_op = { .type = KW_MODIFIER, .declarator = auto_specifier, @@ -440,6 +446,8 @@ static struct init_keyword { { "_Noreturn", NS_TYPEDEF, .op = &noreturn_op }, + { "_Alignas", NS_TYPEDEF, .op = &alignas_op }, + /* Ignored for now.. */ { "restrict", NS_TYPEDEF, .op = &restrict_op}, { "__restrict", NS_TYPEDEF, .op = &restrict_op}, @@ -1382,6 +1390,41 @@ static struct token *noreturn_specifier(struct token *next, struct decl_state *c return next; } +static struct token *alignas_specifier(struct token *token, struct decl_state *ctx) +{ + int alignment = 0; + + if (!match_op(token, '(')) { + sparse_error(token->pos, "expected '(' after _Alignas"); + return token; + } + if (lookup_type(token->next)) { + struct symbol *sym = NULL; + token = typename(token->next, &sym, NULL); + sym = examine_symbol_type(sym); + alignment = sym->ctype.alignment; + token = expect(token, ')', "after _Alignas(..."); + } else { + struct expression *expr = NULL; + token = parens_expression(token, &expr, "after _Alignas"); + if (!expr) + return token; + alignment = const_expression_value(expr); + } + + if (alignment < 0) { + warning(token->pos, "non-positive alignment"); + return token; + } + if (alignment & (alignment-1)) { + warning(token->pos, "non-power-of-2 alignment"); + return token; + } + if (alignment > ctx->ctype.alignment) + ctx->ctype.alignment = alignment; + return token; +} + static struct token *const_qualifier(struct token *next, struct decl_state *ctx) { apply_qualifier(&next->pos, &ctx->ctype, MOD_CONST); diff --git a/validation/c11-alignas.c b/validation/c11-alignas.c new file mode 100644 index 00000000..4b264a5d --- /dev/null +++ b/validation/c11-alignas.c @@ -0,0 +1,40 @@ +static _Alignas(8) int v; +static _Alignas(long) int t; +static _Alignas(void *) int p; +static _Alignas(int[4]) int a; +static _Alignas(0) int z; +static _Alignas(3) int bnpow2; +static _Alignas(-1) int bneg; +static _Alignas(-2) int bnegpow2; +static _Alignas(v) int bnc; +static _Alignas(+) int bsyn; + +static int check(void) +{ + if (_Alignof(v) != 8) + return -1; + if (_Alignof(t) != _Alignof(long)) + return -1; + if (_Alignof(p) != _Alignof(void *)) + return -1; + if (_Alignof(a) != _Alignof(int)) + return -1; + + return 0; +} + +/* + * check-name: c11-alignas + * check-command: test-linearize -std=c11 $file + * + * check-error-start +c11-alignas.c:6:25: warning: non-power-of-2 alignment +c11-alignas.c:7:25: warning: non-positive alignment +c11-alignas.c:8:25: warning: non-positive alignment +c11-alignas.c:9:17: error: bad constant expression +c11-alignas.c:10:17: error: Syntax error in unary expression + * check-error-end + * + * check-output-ignore + * check-output-contains: ret\\.32 *\$0 + */ -- 2.11.0