From patchwork Sat Apr 10 13:30:45 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Luc Van Oostenryck X-Patchwork-Id: 12195609 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 640B6C433ED for ; Sat, 10 Apr 2021 13:31:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 379D361028 for ; Sat, 10 Apr 2021 13:31:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234091AbhDJNbR (ORCPT ); Sat, 10 Apr 2021 09:31:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43954 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234806AbhDJNbP (ORCPT ); Sat, 10 Apr 2021 09:31:15 -0400 Received: from mail-ed1-x52d.google.com (mail-ed1-x52d.google.com [IPv6:2a00:1450:4864:20::52d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1BEF1C061764 for ; Sat, 10 Apr 2021 06:31:01 -0700 (PDT) Received: by mail-ed1-x52d.google.com with SMTP id x4so9722617edd.2 for ; Sat, 10 Apr 2021 06:31:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=7GyhyKuCGDerdGuoNjbX1b5UU6r+UUpK9bAjsPh002U=; b=Lfov4o0wSsKkgCwmT00i//X0LmRgtQNOPv8TcIHRS6o4BLlGXDQhMvCnHKCG/CjTBd BW8LTLNoXeP8+vqpdMVbT1G8NdUZH+jtJl72iIJvxosDxXOcP9XlaS38IIpPbbdicrsE uLUCJefWdsbKJTNGzp9Nd9UaWgHwxFrPP6QPTHyWVzW9WsqK8idBz2MYCtKwX5RpVLA8 X04hrdlGGCEsyBzXUVmicD0Ikf2EE0l/94bG6pi1AD6N03jydxHrKhiyUtjOdGcYI53F 6Fe+2l5V5Ngok686brxZ/kgw/FVS9a/A6Ij6mWNjMyGbe5ue/dosELf+WLub4XwRk6ao Op0Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=7GyhyKuCGDerdGuoNjbX1b5UU6r+UUpK9bAjsPh002U=; b=cAadWSb+Yx864AZAJ0injWnxOZbJxU7GdCYkW+8ozJReW31JZCy0As8S/cfXOio5gb y6XtvlaMBkf8Mhxh+2wxlwu6exsiuF4tTZX80ObKk1hMPM7U2tNBleZn8pATXDU3gy+c cbBIfysFVqFWa1KhtRBTfpfoPjoyrysBvt+ElDrO5oQ+yTnvpm7p/XMR4KhUTOV5WWvc lZi9+YXiFhdytpYh0NpYG4+oicoVTDppOPhQSfIQnF06SSSt9bAqu5ep55HK0jvr98S3 q3RCVz2nZp2DXXP7zDjTDoZo4mNRRFjr5wfSY3vNGUpt9JF3i+8SC/M7tX9yiIuzE0Kd RQNw== X-Gm-Message-State: AOAM53125rYBeK8xt1R4smDnt25ttBEeEC00ZphkIvc81UgqyAgjyMux uaBqG5aflrcIbASRSDokO8dGbgM6h+8= X-Google-Smtp-Source: ABdhPJxz5c34O3QoJqQn0esRVm8ihzJD7Cd135ks7yNNyKAfmhgFz6bQK9Ck63Ak+2bzlsa85/CYYQ== X-Received: by 2002:a50:85cd:: with SMTP id q13mr22115272edh.114.1618061459901; Sat, 10 Apr 2021 06:30:59 -0700 (PDT) Received: from localhost.localdomain ([2a02:a03f:b7fe:f700:f96a:804d:4fe5:372f]) by smtp.gmail.com with ESMTPSA id g26sm2594910ejz.70.2021.04.10.06.30.59 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 10 Apr 2021 06:30:59 -0700 (PDT) From: Luc Van Oostenryck To: linux-sparse@vger.kernel.org Cc: Luc Van Oostenryck Subject: [PATCH 8/8] scheck: support pre-conditions via __assume() Date: Sat, 10 Apr 2021 15:30:45 +0200 Message-Id: <20210410133045.53189-9-luc.vanoostenryck@gmail.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210410133045.53189-1-luc.vanoostenryck@gmail.com> References: <20210410133045.53189-1-luc.vanoostenryck@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-sparse@vger.kernel.org A lot of simplifications are only valid when their variables satisfy to some conditions (like "is within a given range" or "is a power of two"). So, allow to add such pre-conditions via new _assume() statements. Internally, all such preconditions are ANDed together and what is checked is they imply the assertions: AND(pre-condition) implies assertion 1 ... Note: IIUC, it seems that boolector has a native mechanism for such things but I'm not sure if t can be used here. Signed-off-by: Luc Van Oostenryck --- ident-list.h | 1 + scheck.c | 33 ++++++++++++++++++++++++--------- validation/scheck/ok.c | 6 ++++++ 3 files changed, 31 insertions(+), 9 deletions(-) diff --git a/ident-list.h b/ident-list.h index 6264fd062534..3c08e8ca9aa4 100644 --- a/ident-list.h +++ b/ident-list.h @@ -79,6 +79,7 @@ IDENT(copy_to_user); IDENT(copy_from_user); IDENT(main); /* used by the symbolic checker */ +IDENT(__assume); IDENT(__assert); IDENT(__assert_eq); IDENT(__assert_const); diff --git a/scheck.c b/scheck.c index ff140aaa1e95..b8bc9bb28498 100644 --- a/scheck.c +++ b/scheck.c @@ -31,6 +31,7 @@ #define dyntype incomplete_ctype static const struct builtin_fn builtins_scheck[] = { + { "__assume", &void_ctype, 0, { &dyntype }, .op = &generic_int_op }, { "__assert", &void_ctype, 0, { &bool_ctype }, .op = &generic_int_op }, { "__assert_eq", &void_ctype, 0, { &dyntype, &dyntype }, .op = &generic_int_op }, { "__assert_const", &void_ctype, 0, { &dyntype, &dyntype }, .op = &generic_int_op }, @@ -184,11 +185,22 @@ static void ternop(Btor *btor, struct instruction *insn) insn->target->priv = t; } -static bool check_btor(Btor *btor, BoolectorNode *n, struct instruction *insn) +static bool add_precondition(Btor *btor, BoolectorNode **pre, struct instruction *insn) +{ + BoolectorNode *a = get_arg(btor, insn, 0); + BoolectorNode *z = boolector_zero(btor, boolector_get_sort(btor, a)); + BoolectorNode *n = boolector_ne(btor, a, z); + BoolectorNode *p = boolector_and(btor, *pre, n); + *pre = p; + return true; +} + +static bool check_btor(Btor *btor, BoolectorNode *p, BoolectorNode *n, struct instruction *insn) { char model_format[] = "btor"; int res; + n = boolector_implies(btor, p, n); boolector_assert(btor, boolector_not(btor, n)); res = boolector_sat(btor); switch (res) { @@ -207,20 +219,20 @@ static bool check_btor(Btor *btor, BoolectorNode *n, struct instruction *insn) return 0; } -static bool check_assert(Btor *btor, struct instruction *insn) +static bool check_assert(Btor *btor, BoolectorNode *pre, struct instruction *insn) { BoolectorNode *a = get_arg(btor, insn, 0); BoolectorNode *z = boolector_zero(btor, boolector_get_sort(btor, a)); BoolectorNode *n = boolector_ne(btor, a, z); - return check_btor(btor, n, insn); + return check_btor(btor, pre, n, insn); } -static bool check_equal(Btor *btor, struct instruction *insn) +static bool check_equal(Btor *btor, BoolectorNode *pre, struct instruction *insn) { BoolectorNode *a = get_arg(btor, insn, 0); BoolectorNode *b = get_arg(btor, insn, 1); BoolectorNode *n = boolector_eq(btor, a, b); - return check_btor(btor, n, insn); + return check_btor(btor, pre, n, insn); } static bool check_const(Btor *ctxt, struct instruction *insn) @@ -239,15 +251,17 @@ static bool check_const(Btor *ctxt, struct instruction *insn) return 0; } -static bool check_call(Btor *btor, struct instruction *insn) +static bool check_call(Btor *btor, BoolectorNode **pre, struct instruction *insn) { pseudo_t func = insn->func; struct ident *ident = func->ident; + if (ident == &__assume_ident) + return add_precondition(btor, pre, insn); if (ident == &__assert_ident) - return check_assert(btor, insn); + return check_assert(btor, *pre, insn); if (ident == &__assert_eq_ident) - return check_equal(btor, insn); + return check_equal(btor, *pre, insn); if (ident == &__assert_const_ident) return check_const(btor, insn); return 0; @@ -256,6 +270,7 @@ static bool check_call(Btor *btor, struct instruction *insn) static bool check_function(struct entrypoint *ep) { Btor *btor = boolector_new(); + BoolectorNode *pre = boolector_true(btor); struct basic_block *bb; int rc = 0; @@ -281,7 +296,7 @@ static bool check_function(struct entrypoint *ep) ternop(btor, insn); break; case OP_CALL: - rc &= check_call(btor, insn); + rc &= check_call(btor, &pre, insn); break; case OP_RET: goto out; diff --git a/validation/scheck/ok.c b/validation/scheck/ok.c index 8f65013e1618..1e5314f24ded 100644 --- a/validation/scheck/ok.c +++ b/validation/scheck/ok.c @@ -10,6 +10,12 @@ static void always(int x) __assert((x - x) == 0); // true and simplified } +static void assumed(int x, int a, int b) +{ + __assume((a & ~b) == 0); + __assert_eq((x ^ a) | b, x | b); +} + /* * check-name: scheck-ok * check-command: scheck $file