From patchwork Tue Nov 22 16:32:52 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christopher Li X-Patchwork-Id: 9441547 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 1CCFD600BA for ; Tue, 22 Nov 2016 16:47:28 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 0BC2A284C7 for ; Tue, 22 Nov 2016 16:47:28 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id F2C98284B6; Tue, 22 Nov 2016 16:47:27 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.3 required=2.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_HI,RCVD_IN_SORBS_SPAM,T_DKIM_INVALID,T_TVD_MIME_EPI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id C539E284B6 for ; Tue, 22 Nov 2016 16:47:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755825AbcKVQrX (ORCPT ); Tue, 22 Nov 2016 11:47:23 -0500 Received: from mail-it0-f66.google.com ([209.85.214.66]:36389 "EHLO mail-it0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751487AbcKVQrV (ORCPT ); Tue, 22 Nov 2016 11:47:21 -0500 Received: by mail-it0-f66.google.com with SMTP id n68so2451840itn.3 for ; Tue, 22 Nov 2016 08:47:21 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:sender:in-reply-to:references:from:date:message-id :subject:to:cc; bh=mtBUDxo5uLFS0/IbNT1pVzlXp18STsBocM8kxG8SPGU=; b=uTAuKtwaliwF9LA9awSv1uu+tRpsmjiF3/Ks31NPyvPudh1oh8TSTyxf3gatvSJzab yisIbhYX8QyqEfzBakW2VMtkEVMfIg0OwI98r831LBxkoWbZPvu8GaxCOfP/CU6uWjbl lsnHrmoNENAbyvQH8mNOgRlAoSK4QCl+pRadmEQL1mc9N2wHMk1o3VfYD8/2wXXUlN74 Qolqad1kLzdJgNqlTgzuSaBW2vHZevHHKXpEkmskxks1Jb17zTiJ/ipHVseXLCL9eoQA EwaIL7uq6DAx75HxODcZs13113Jn1Ttn65w+0QiOtInsYTmyWwXkk67a5I9J18LVsCd8 wONg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:sender:in-reply-to:references:from :date:message-id:subject:to:cc; bh=mtBUDxo5uLFS0/IbNT1pVzlXp18STsBocM8kxG8SPGU=; b=AUzCDMJOewlfEX0Xe11xbV0oP69KVFseAv7H5I+nuvGKp+IweyI5tabZAqmQ6/bjtC UUru2oOJv55Dr30ibAs599caRbQJm1xKNXoSgwQ6w45uw41XAYcUeDlffLAN/Fvn9vZk fslnrrnAWY3tHB52KXsSejoeyLkyJnKYcI17eAjUS1OiPLjrT6DBLkEm5hLvAV6Tyou9 JbFAGWtxOC5ewqCrcEOfQLpXLwx9Wb0mAW0Tm0gdRSZdW/MtVCCcPC2QTE3d+lImCwnx mJpRrIgc+OQjfQ4DXNd5wE8ZzX3h/AEhOIQB4SwC+IQ5SQbXXM2jPpe6AFbeBXz0Fnla w90g== X-Gm-Message-State: AKaTC02uK3kiLAs8Dc0efV8YfkKgMDR9pbKDjF2gN9c6ynTmpIZcm7EWfgsVZTcI9NyF6Z8hTeU9E8NMMOnv7Q== X-Received: by 10.36.14.84 with SMTP id 81mr1916529ite.54.1479832373094; Tue, 22 Nov 2016 08:32:53 -0800 (PST) MIME-Version: 1.0 Received: by 10.36.209.68 with HTTP; Tue, 22 Nov 2016 08:32:52 -0800 (PST) In-Reply-To: <20161122131543.GA8370@macbook.local> References: <20161117095503.8754-1-johannes@sipsolutions.net> <1479721551.8662.10.camel@sipsolutions.net> <20161122131543.GA8370@macbook.local> From: Christopher Li Date: Wed, 23 Nov 2016 00:32:52 +0800 X-Google-Sender-Auth: 604HspX1KSDEzKXtBa3bs5gb-4w Message-ID: Subject: Re: [PATCH v2] implement constant-folding in __builtin_bswap*() To: Luc Van Oostenryck Cc: Johannes Berg , Linux-Sparse , Nicolai Stange Sender: linux-sparse-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-sparse@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP On Tue, Nov 22, 2016 at 9:15 PM, Luc Van Oostenryck wrote: >> >> I will see if I can hack up some thing very quick. I get it working in the end. Not too far from what I thought. Patch attach here for review. > > I think it would be best to do any change related tos handling > of constant expressions on to of Nicolai Stange's serie: > http://marc.info/?l=linux-sparse&m=145429372932235 Yes, it is on my patch list. That series can still apply clean. I just check it. My current strategy is apply other patches which have impact on the sparse warning first. Otherwise my anxiety level is too high, make me hard to pick up and hack sparse. That integer series needs a relative big chunk of time to review it. For me it is more important to keep on making progress rather than solve all problem in one blow. I think I have been catch up with most of the patches. Should be able to work on that soon. Chris Tested-by: Luc Van Oostenryck diff --git a/expand.c b/expand.c index 0f6720c..1ef95ea 100644 --- a/expand.c +++ b/expand.c @@ -802,6 +802,44 @@ int expand_safe_p(struct expression *expr, int cost) return 0; } +/* The arguments are constant if the cost of all of them is zero */ +int expand_bswap(struct expression *expr, int cost) +{ + struct symbol *sym; + struct expression_list *args = expr->args; + long long input; + + if (cost) + return cost; + + sym = expr->fn->ctype; + if (expression_list_size(args) != 1) { + sparse_error(expr->pos, "not enough arguments for function %s", + show_ident(sym->ident)); + return SIDE_EFFECTS; + } + + input = const_expression_value(first_expression(args)); + + if (sym->ident == &__builtin_bswap16_ident) { + expr->value = __builtin_bswap16(input); + expr->ctype = &ushort_ctype; + } else if (sym->ident == &__builtin_bswap32_ident) { + expr->value = __builtin_bswap32(input); + expr->ctype = &uint_ctype; + } else if (sym->ident == &__builtin_bswap64_ident) { + expr->value = __builtin_bswap64(input); + expr->ctype = &ullong_ctype; + } else { + die("Unexpected __builtin_bswap symbol %s\n", show_ident(sym->ident)); + } + + expr->type = EXPR_VALUE; + expr->taint = 0; + return 0; +} + + /* * expand a call expression with a symbol. This * should expand builtins. diff --git a/ident-list.h b/ident-list.h index b65b667..a683f6c 100644 --- a/ident-list.h +++ b/ident-list.h @@ -35,6 +35,9 @@ IDENT_RESERVED(__sizeof_ptr__); IDENT_RESERVED(__builtin_types_compatible_p); IDENT_RESERVED(__builtin_offsetof); IDENT_RESERVED(__label__); +IDENT(__builtin_bswap16); +IDENT(__builtin_bswap32); +IDENT(__builtin_bswap64); /* Attribute names */ IDENT(packed); IDENT(__packed__); diff --git a/lib.c b/lib.c index 2660575..7e35049 100644 --- a/lib.c +++ b/lib.c @@ -819,40 +819,6 @@ void declare_builtin_functions(void) add_pre_buffer("extern int __builtin_popcountl(unsigned long);\n"); add_pre_buffer("extern int __builtin_popcountll(unsigned long long);\n"); - /* And byte swaps.. */ - add_pre_buffer("extern unsigned short ____builtin_bswap16(unsigned short);\n"); - add_pre_buffer("extern unsigned int ____builtin_bswap32(unsigned int);\n"); - add_pre_buffer("extern unsigned long long ____builtin_bswap64(unsigned long long);\n"); - add_pre_buffer("#define __sparse_constant_swab16(x) ((unsigned short)(" - " (((unsigned short)(x) & (unsigned short)0x00ffU) << 8) |" - " (((unsigned short)(x) & (unsigned short)0xff00U) >> 8)))\n"); - add_pre_buffer("#define __sparse_constant_swab32(x) ((unsigned int)(" - " (((unsigned int)(x) & (unsigned int)0x000000ffUL) << 24) |" - " (((unsigned int)(x) & (unsigned int)0x0000ff00UL) << 8) |" - " (((unsigned int)(x) & (unsigned int)0x00ff0000UL) >> 8) |" - " (((unsigned int)(x) & (unsigned int)0xff000000UL) >> 24)))\n"); - add_pre_buffer("#define __sparse_constant_swab64(x) ((unsigned long long)(" - " (((unsigned long long)(x) & (unsigned long long)0x00000000000000ffULL) << 56) |" - " (((unsigned long long)(x) & (unsigned long long)0x000000000000ff00ULL) << 40) |" - " (((unsigned long long)(x) & (unsigned long long)0x0000000000ff0000ULL) << 24) |" - " (((unsigned long long)(x) & (unsigned long long)0x00000000ff000000ULL) << 8) |" - " (((unsigned long long)(x) & (unsigned long long)0x000000ff00000000ULL) >> 8) |" - " (((unsigned long long)(x) & (unsigned long long)0x0000ff0000000000ULL) >> 24) |" - " (((unsigned long long)(x) & (unsigned long long)0x00ff000000000000ULL) >> 40) |" - " (((unsigned long long)(x) & (unsigned long long)0xff00000000000000ULL) >> 56)))\n"); - add_pre_buffer("#define __builtin_bswap16(x)" - " (__builtin_constant_p((unsigned short)(x)) ?" - " __sparse_constant_swab16(x) :" - " ____builtin_bswap16(x))\n"); - add_pre_buffer("#define __builtin_bswap32(x)" - " (__builtin_constant_p((unsigned int)(x)) ?" - " __sparse_constant_swab32(x) :" - " ____builtin_bswap32(x))\n"); - add_pre_buffer("#define __builtin_bswap64(x)" - " (__builtin_constant_p((unsigned long long)(x)) ?" - " __sparse_constant_swab64(x) :" - " ____builtin_bswap64(x))\n"); - /* And atomic memory access functions.. */ add_pre_buffer("extern int __sync_fetch_and_add(void *, ...);\n"); add_pre_buffer("extern int __sync_fetch_and_sub(void *, ...);\n"); diff --git a/lib.h b/lib.h index b778bdc..306ee45 100644 --- a/lib.h +++ b/lib.h @@ -200,6 +200,11 @@ static inline struct instruction *first_instruction(struct instruction_list *hea return first_ptr_list((struct ptr_list *)head); } +static inline struct expression *first_expression(struct expression_list *head) +{ + return first_ptr_list((struct ptr_list *)head); +} + static inline pseudo_t first_pseudo(struct pseudo_list *head) { return first_ptr_list((struct ptr_list *)head); diff --git a/symbol.c b/symbol.c index 92a7a62..e57f207 100644 --- a/symbol.c +++ b/symbol.c @@ -773,6 +773,11 @@ static struct symbol_op choose_op = { .args = arguments_choose, }; +static struct symbol_op bswap_op = { + .evaluate = evaluate_to_integer, + .expand = expand_bswap +}; + /* * Builtin functions */ @@ -788,6 +793,9 @@ static struct sym_init { { "__builtin_warning", &builtin_fn_type, MOD_TOPLEVEL, &warning_op }, { "__builtin_expect", &builtin_fn_type, MOD_TOPLEVEL, &expect_op }, { "__builtin_choose_expr", &builtin_fn_type, MOD_TOPLEVEL, &choose_op }, + { "__builtin_bswap16", &builtin_fn_type, MOD_TOPLEVEL, &bswap_op }, + { "__builtin_bswap32", &builtin_fn_type, MOD_TOPLEVEL, &bswap_op }, + { "__builtin_bswap64", &builtin_fn_type, MOD_TOPLEVEL, &bswap_op }, { NULL, NULL, 0 } }; diff --git a/symbol.h b/symbol.h index 9b3f160..48bbfce 100644 --- a/symbol.h +++ b/symbol.h @@ -130,6 +130,7 @@ struct symbol_op { extern int expand_safe_p(struct expression *expr, int cost); extern int expand_constant_p(struct expression *expr, int cost); +extern int expand_bswap(struct expression *expr, int cost); #define SYM_ATTR_WEAK 0 #define SYM_ATTR_NORMAL 1