From patchwork Sat Apr 8 21:18:59 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Luc Van Oostenryck X-Patchwork-Id: 9671323 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 A15D960365 for ; Sat, 8 Apr 2017 21:19:18 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 936AE28387 for ; Sat, 8 Apr 2017 21:19:18 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 87C2C28421; Sat, 8 Apr 2017 21:19:18 +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=-6.8 required=2.0 tests=BAYES_00, DKIM_ADSP_CUSTOM_MED, DKIM_SIGNED, FREEMAIL_FROM, RCVD_IN_DNSWL_HI, T_DKIM_INVALID 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 0419828387 for ; Sat, 8 Apr 2017 21:19:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752338AbdDHVTR (ORCPT ); Sat, 8 Apr 2017 17:19:17 -0400 Received: from mail-wm0-f66.google.com ([74.125.82.66]:36694 "EHLO mail-wm0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752187AbdDHVTQ (ORCPT ); Sat, 8 Apr 2017 17:19:16 -0400 Received: by mail-wm0-f66.google.com with SMTP id q125so3594308wmd.3 for ; Sat, 08 Apr 2017 14:19:16 -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; bh=qqa9wO26h8TsiDbqD/Rx4dq9WdYwMcHaCr/ENvoQ4nQ=; b=i7+0r61veWYQ7Fyv961uxMKNzT+3EayoxQXmSPAowzux5jclXpTyEUyAV9+NbDIOxP wDzwagJ6+K4Jylo2bggYbQa3vjbUnWWMBtHNFjXqdxIG2rQ8qRFDUgz8ZGs+ICPI9xBE bgHbr7Qq96VtTW9JNUsllEHBxqaWBSclkTFdr/X+PRrzpRoziZik+WAU1jNYqUu9UTxC xy0Brhuow2L6U2V6XQ7XEyzDVAqqZPObnnEt4v2l06SyW+y4/eRq55r8/vRbafx3pMeU u8ilS2LsMyOSj0Hkm5blnLOAdTyed6OUdzJLkzUo1Nlo+T4pKygIUXv0MTURL/Zz5wJl G4Kg== 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; bh=qqa9wO26h8TsiDbqD/Rx4dq9WdYwMcHaCr/ENvoQ4nQ=; b=dGe8wZTepUk0BgCHgvpyiWTUZNwGFKB71K61Fk9jpEd/As7u3ntvDWyt6ufjy39suy qclbyJvJhSblDyN0FL8vq3AZH3j3fcAe6lsJeGJAFuPerXWOLW6gTSxSYsm5Q49gRjaD VjPacmOeaux+iwUpu7qrlq32ayuTuIkNFyTGg+581YHGalnJvnqoiVFGigAAWa0pqDEC QYoZSEVj8skIT0c276K8qLzNqTBsuJbXw8uTjfqZ3XPjGaMkd+v3Elf9fzMIl8Zgh4ht ePOq1fHOsyC2zErajmN/7DgngCzb+eX3ZWSv3RJ5+ooafPznyE1gLlxh658NJzLBxJ3b mMgg== X-Gm-Message-State: AN3rC/6w0JrPuZ8BP1GmwuEIz6loCgl0QY2Igho7ipE2MQQTrSfkbwuk JGa1dbehD9XPfttc0cg= X-Received: by 10.28.169.199 with SMTP id s190mr4335090wme.2.1491686355076; Sat, 08 Apr 2017 14:19:15 -0700 (PDT) Received: from localhost.localdomain ([2a02:a03f:88d:1900:3d63:d6f1:4c06:8f0f]) by smtp.gmail.com with ESMTPSA id n5sm4032362wmf.14.2017.04.08.14.19.14 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sat, 08 Apr 2017 14:19:14 -0700 (PDT) From: Luc Van Oostenryck To: linux-sparse@vger.kernel.org Cc: Luc Van Oostenryck Subject: [PATCH v2 4/6] fix implicit zero initializer. Date: Sat, 8 Apr 2017 23:18:59 +0200 Message-Id: <20170408211901.40507-5-luc.vanoostenryck@gmail.com> X-Mailer: git-send-email 2.12.0 In-Reply-To: <20170408211901.40507-1-luc.vanoostenryck@gmail.com> References: <20170408211901.40507-1-luc.vanoostenryck@gmail.com> 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 The C standard requires that, when initializing an aggregate, all fieds not explicitly initialized shall be implicity zero-initialized (more exactly "the same as objects that have static storage duration" [6.7.9.21]). Until now sparse didn't did this. Fix this (when an initializer is present and the object not a scalar) by first storing zeroes in the whole object before doing the initialization of each fields explicitly initialized. Note 1: this patch initialize the *whole* aggregate while the standard only requires that existing fields are initialized. Thanks to Linus to notice this. Note 2: this implicit initialization is not needed if all fields are explicitly initialized but is done anyway, for the moment. Note 3: the code simplify nicely when there is a single field that is initialized, much less so when there is several ones. Signed-off-by: Luc Van Oostenryck --- linearize.c | 15 +++++ validation/linear/bitfield-init-zero.c | 102 ++++++++++++++++++++++++++++++++ validation/linear/struct-init-full.c | 28 +++++++++ validation/linear/struct-init-partial.c | 41 +++++++++++++ 4 files changed, 186 insertions(+) create mode 100644 validation/linear/bitfield-init-zero.c create mode 100644 validation/linear/struct-init-full.c create mode 100644 validation/linear/struct-init-partial.c diff --git a/linearize.c b/linearize.c index 5c273a91d..f628f5a74 100644 --- a/linearize.c +++ b/linearize.c @@ -1635,6 +1635,21 @@ static pseudo_t linearize_one_symbol(struct entrypoint *ep, struct symbol *sym) sym->initialized = 1; ad.address = symbol_pseudo(ep, sym); + + if (sym->initializer && !is_scalar_type(sym)) { + // default zero initialization [6.7.9.21] + // FIXME: this init the whole aggregate while + // only the existing fields need to be initialized. + // FIXME: this init the whole aggregate even if + // all fields arelater explicitely initialized. + struct expression *expr = sym->initializer; + ad.pos = expr->pos; + ad.result_type = sym; + ad.source_type = base_type(sym); + ad.address = symbol_pseudo(ep, sym); + linearize_store_gen(ep, value_pseudo(0), &ad); + } + value = linearize_initializer(ep, sym->initializer, &ad); finish_address_gen(ep, &ad); return value; diff --git a/validation/linear/bitfield-init-zero.c b/validation/linear/bitfield-init-zero.c new file mode 100644 index 000000000..39a64345e --- /dev/null +++ b/validation/linear/bitfield-init-zero.c @@ -0,0 +1,102 @@ +struct bfu { + unsigned int a:11; + unsigned int f:9; + unsigned int :2; + unsigned int z:3; +}; + +struct bfu bfuu_init(unsigned int a) +{ + struct bfu bf = { .f = a, }; + return bf; +} + +struct bfu bfus_init(int a) +{ + struct bfu bf = { .f = a, }; + return bf; +} + +unsigned int bfu_get0(void) +{ + struct bfu bf = { }; + return bf.f; +} + + +struct bfs { + signed int a:11; + signed int f:9; + signed int :2; + signed int z:3; +}; + +struct bfs bfsu_init(unsigned int a) +{ + struct bfs bf = { .f = a, }; + return bf; +} + +struct bfs bfss_init(int a) +{ + struct bfs bf = { .f = a, }; + return bf; +} + +int bfs_get0(void) +{ + struct bfs bf = { }; + return bf.f; +} + +/* + * check-name: bitfield implicit init zero + * check-command: test-linearize -Wno-decl $file + * + * check-output-start +bfuu_init: +.L0: + + cast.9 %r2 <- (32) %arg1 + shl.32 %r4 <- %r2, $11 + ret.32 %r4 + + +bfus_init: +.L2: + + scast.9 %r10 <- (32) %arg1 + shl.32 %r12 <- %r10, $11 + ret.32 %r12 + + +bfu_get0: +.L4: + + ret.32 $0 + + +bfsu_init: +.L6: + + cast.9 %r23 <- (32) %arg1 + shl.32 %r25 <- %r23, $11 + ret.32 %r25 + + +bfss_init: +.L8: + + scast.9 %r31 <- (32) %arg1 + shl.32 %r33 <- %r31, $11 + ret.32 %r33 + + +bfs_get0: +.L10: + + ret.32 $0 + + + * check-output-end + */ diff --git a/validation/linear/struct-init-full.c b/validation/linear/struct-init-full.c new file mode 100644 index 000000000..f1b03db71 --- /dev/null +++ b/validation/linear/struct-init-full.c @@ -0,0 +1,28 @@ +struct s { + int a, b, c; +}; + +struct s s_init_all(int a) +{ + struct s s = { .a = a, .b = 42, .c = 123, }; + return s; +} + +/* + * check-name: struct implicit init zero not needed + * check-command: test-linearize -Wno-decl $file + * check-known-to-fail + * + * check-output-start +s_init_all: +.L4: + + store.32 %arg1 -> 0[s] + store.32 $42 -> 4[s] + store.32 $123 -> 8[s] + load.96 %r8 <- 0[s] + ret.96 %r8 + + + * check-output-end + */ diff --git a/validation/linear/struct-init-partial.c b/validation/linear/struct-init-partial.c new file mode 100644 index 000000000..1f5078bfa --- /dev/null +++ b/validation/linear/struct-init-partial.c @@ -0,0 +1,41 @@ +struct s { + int a, b, c; +}; + +struct s s_init_first(int a) +{ + struct s s = { .a = a, }; + return s; +} + +struct s s_init_third(int a) +{ + struct s s = { .c = a, }; + return s; +} + +/* + * check-name: struct implicit init zero needed + * check-command: test-linearize -Wno-decl $file + * + * check-output-start +s_init_first: +.L0: + + store.96 $0 -> 0[s] + store.32 %arg1 -> 0[s] + load.96 %r2 <- 0[s] + ret.96 %r2 + + +s_init_third: +.L2: + + store.96 $0 -> 0[s] + store.32 %arg1 -> 8[s] + load.96 %r5 <- 0[s] + ret.96 %r5 + + + * check-output-end + */