From patchwork Fri Jan 13 18:27:21 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Richard Henderson X-Patchwork-Id: 642038 Delivered-To: patch@linaro.org Received: by 2002:a17:522:f3c4:b0:4b4:3859:abed with SMTP id in4csp357852pvb; Fri, 13 Jan 2023 10:28:08 -0800 (PST) X-Google-Smtp-Source: AMrXdXu31Wi7tXtwGDoujgfTDSxKE32RbmIHxk0NsuDx5milW4x4AxSaIS3RxIkuWrb1eyoUAHpS X-Received: by 2002:a17:907:2d09:b0:86c:988d:178c with SMTP id gs9-20020a1709072d0900b0086c988d178cmr230324ejc.52.1673634488418; Fri, 13 Jan 2023 10:28:08 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1673634488; cv=none; d=google.com; s=arc-20160816; b=sDrl+7IZ6PHSCMQJ3dPI8py0Gnq0vh7mDD4v5nljVtBbCbJ6pIuG7C78XzUehvZXga SyHywD5u/W4s5oE+9V8t+RAgxO2xo4lC+jxAzKxHtXUDsDxPTCGB/fr0Un7pqIG7HP3Q 22CGhH43vKBsOIDdyvfKx2GX6joj8xrFcQ1llTFX3PVlGR8Evlq0sxNO80ovzYpnDSaF Snn8/HvgR/o3RUloYIJZ5IlhR47j20e0EDE9SXd9hL7tDoHVjjXg1CLB06qUuHJdg3O6 LVT1ChZ+p90TkBkNJmxHUdvb/bjoAQsqC7gs6rS0G6J7n0j5WX6MIvqbb+cHwjG/kQSV PGTw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=sender:errors-to:reply-to:from:list-subscribe:list-help:list-post :list-archive:list-unsubscribe:list-id:precedence :content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:dmarc-filter:delivered-to :dkim-signature:dkim-filter; bh=OqHYFL+CdMGKg9rYN0RAWE2xppStfJKEdo6sEDhhdCk=; b=lWLcxCln4+f4ghEYM1qfrlryRhznXfvFU9t63NHlNclaVC/mlgvNEWfSWr88jVS4qq Q8aBqXOu246D2W/Cmgv7dpwBsoXtYjbqgp7rT7nt1S7X8KPY+CeGCa0/yuzynkE/ETaM jCknTNguFjeCONAMhRrNRAx4ugAXEgD4oR+vWWp4dMQr+YA4gWbu3OZIGU+UUVgG7saH u8P2TxoupiA+UpdhRjxZsjeoBfieOnDw/HOgntUpJgqdwrUmX2ooPtFrmpvLH6ksqOjh j2Gj1SFdL/+jhaLoeCNcfgp8CK2p2o4QR0le0yJc5p+2kSpjauknoUviCeXgS0GlJDxO Hd6Q== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@sourceware.org header.s=default header.b=iOkX7Xcw; spf=pass (google.com: domain of libc-alpha-bounces+patch=linaro.org@sourceware.org designates 2620:52:3:1:0:246e:9693:128c as permitted sender) smtp.mailfrom="libc-alpha-bounces+patch=linaro.org@sourceware.org"; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=sourceware.org Return-Path: Received: from sourceware.org (server2.sourceware.org. [2620:52:3:1:0:246e:9693:128c]) by mx.google.com with ESMTPS id dt19-20020a170907729300b007a7f207a1b9si20567567ejc.664.2023.01.13.10.28.08 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 13 Jan 2023 10:28:08 -0800 (PST) Received-SPF: pass (google.com: domain of libc-alpha-bounces+patch=linaro.org@sourceware.org designates 2620:52:3:1:0:246e:9693:128c as permitted sender) client-ip=2620:52:3:1:0:246e:9693:128c; Authentication-Results: mx.google.com; dkim=pass header.i=@sourceware.org header.s=default header.b=iOkX7Xcw; spf=pass (google.com: domain of libc-alpha-bounces+patch=linaro.org@sourceware.org designates 2620:52:3:1:0:246e:9693:128c as permitted sender) smtp.mailfrom="libc-alpha-bounces+patch=linaro.org@sourceware.org"; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=sourceware.org Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id 1048F3881D07 for ; Fri, 13 Jan 2023 18:28:07 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 1048F3881D07 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1673634487; bh=OqHYFL+CdMGKg9rYN0RAWE2xppStfJKEdo6sEDhhdCk=; h=To:Cc:Subject:Date:In-Reply-To:References:List-Id: List-Unsubscribe:List-Archive:List-Post:List-Help:List-Subscribe: From:Reply-To:From; b=iOkX7XcwnAvVBK4DQc8o/ZF4VQkxdVpMiEQaS33O7hJoPGwrj9AdVgEWCUzsPz7r6 Z7bdLokfwYeakcV+0nueq1qg9Z+Qf/4OEU6+afTK3SpKt3Sn5MEn2hr/buYyvS0sI6 s9xgaDxpbhvdK/Ri7eLCzBM9d95SVXPtGv0lHfhI= X-Original-To: libc-alpha@sourceware.org Delivered-To: libc-alpha@sourceware.org Received: from mail-pj1-x1034.google.com (mail-pj1-x1034.google.com [IPv6:2607:f8b0:4864:20::1034]) by sourceware.org (Postfix) with ESMTPS id 0053A38493FF for ; Fri, 13 Jan 2023 18:27:44 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 0053A38493FF Received: by mail-pj1-x1034.google.com with SMTP id o18so2057790pji.1 for ; Fri, 13 Jan 2023 10:27:44 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=OqHYFL+CdMGKg9rYN0RAWE2xppStfJKEdo6sEDhhdCk=; b=YsGlOjTZTsb4HRxf56z0EU+1ecWNKBtaFPWi/HWvbOyerQKFix7E89QjjkslKW8fxj yb9/Y+yC9WDAYSv6TNViK4xr1s/URKZj18/Oqlaoq+XUpobcqr/YTVZNp8SozLEUi4GD +g85Sm7XIRQudvY8XvyQGnlAADy5wTpxxZVJeGD3tdvT/T956rSWa/xfn6L96FzyGNu+ Mojk4iXJBMO9vfTHRRJw3m52MPESCMTlAN6nIU0qK3XuEH9vkwNRjf1e6KaaJ0+L9X6H MSK6jBmPpaJvHnei5ckYQC5fK5sjUp+tr4n+lVnALhx2uU5jsWI9fnN8CYUsF0BjzMjm QgNA== X-Gm-Message-State: AFqh2kqDdiGf9ZVaAiSHgRTpYOyCi6iPKsn1j4v+M5z2qHsPiR2EraQV +QNmE6va4eHn8rHgZAxDHEwpuSpDCC70M/57 X-Received: by 2002:a17:902:6945:b0:194:7536:de5f with SMTP id k5-20020a170902694500b001947536de5fmr1923829plt.56.1673634463990; Fri, 13 Jan 2023 10:27:43 -0800 (PST) Received: from stoup.. (rrcs-173-198-77-218.west.biz.rr.com. [173.198.77.218]) by smtp.gmail.com with ESMTPSA id s17-20020a170902c65100b001927ebc40e2sm14443640pls.193.2023.01.13.10.27.42 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 13 Jan 2023 10:27:43 -0800 (PST) To: libc-alpha@sourceware.org Cc: adhemerval.zanella@linaro.org, goldstein.w.n@gmail.com Subject: [PATCH v8 05/17] string: Improve generic strlen Date: Fri, 13 Jan 2023 08:27:21 -1000 Message-Id: <20230113182733.1268668-6-richard.henderson@linaro.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230113182733.1268668-1-richard.henderson@linaro.org> References: <20230113182733.1268668-1-richard.henderson@linaro.org> MIME-Version: 1.0 X-Spam-Status: No, score=-11.8 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, GIT_PATCH_0, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, 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 X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-Patchwork-Original-From: Richard Henderson via Libc-alpha From: Richard Henderson Reply-To: Richard Henderson Errors-To: libc-alpha-bounces+patch=linaro.org@sourceware.org Sender: "Libc-alpha" From: Adhemerval Zanella Netto New algorithm have the following key differences: - Reads first word unaligned and use string-maskoff functions to remove unwanted data. This strategy follow arch-specific optimization used on powerpc, sparc, and SH. - Use of has_zero and index_first_zero parametrized functions. Checked on x86_64-linux-gnu, i686-linux-gnu, powerpc-linux-gnu, and powercp64-linux-gnu by removing the arch-specific assembly implementation and disabling multi-arch (it covers both LE and BE for 64 and 32 bits). Co-authored-by: Richard Henderson Message-Id: <20230111204558.2402155-6-adhemerval.zanella@linaro.org> --- string/strlen.c | 87 +++++++++-------------------------------- sysdeps/s390/strlen-c.c | 12 +++--- 2 files changed, 25 insertions(+), 74 deletions(-) diff --git a/string/strlen.c b/string/strlen.c index ee1aae0fff..9769dc62c3 100644 --- a/string/strlen.c +++ b/string/strlen.c @@ -17,84 +17,33 @@ #include #include +#include +#include +#include +#include -#undef strlen - -#ifndef STRLEN -# define STRLEN strlen +#ifdef STRLEN +# define __strlen STRLEN #endif /* Return the length of the null-terminated string STR. Scan for the null terminator quickly by testing four bytes at a time. */ size_t -STRLEN (const char *str) +__strlen (const char *str) { - const char *char_ptr; - const unsigned long int *longword_ptr; - unsigned long int longword, himagic, lomagic; + /* Align pointer to sizeof op_t. */ + const uintptr_t s_int = (uintptr_t) str; + const op_t *word_ptr = word_containing (str); - /* Handle the first few characters by reading one character at a time. - Do this until CHAR_PTR is aligned on a longword boundary. */ - for (char_ptr = str; ((unsigned long int) char_ptr - & (sizeof (longword) - 1)) != 0; - ++char_ptr) - if (*char_ptr == '\0') - return char_ptr - str; + /* Read and MASK the first word. */ + op_t word = *word_ptr | create_mask (s_int); - /* All these elucidatory comments refer to 4-byte longwords, - but the theory applies equally well to 8-byte longwords. */ + while (! has_zero (word)) + word = *++word_ptr; - longword_ptr = (unsigned long int *) char_ptr; - - /* Computing (longword - lomagic) sets the high bit of any corresponding - byte that is either zero or greater than 0x80. The latter case can be - filtered out by computing (~longword & himagic). The final result - will always be non-zero if one of the bytes of longword is zero. */ - himagic = 0x80808080L; - lomagic = 0x01010101L; - if (sizeof (longword) > 4) - { - /* 64-bit version of the magic. */ - /* Do the shift in two steps to avoid a warning if long has 32 bits. */ - himagic = ((himagic << 16) << 16) | himagic; - lomagic = ((lomagic << 16) << 16) | lomagic; - } - if (sizeof (longword) > 8) - abort (); - - /* Instead of the traditional loop which tests each character, - we will test a longword at a time. The tricky part is testing - if *any of the four* bytes in the longword in question are zero. */ - for (;;) - { - longword = *longword_ptr++; - - if (((longword - lomagic) & ~longword & himagic) != 0) - { - /* Which of the bytes was the zero? */ - - const char *cp = (const char *) (longword_ptr - 1); - - if (cp[0] == 0) - return cp - str; - if (cp[1] == 0) - return cp - str + 1; - if (cp[2] == 0) - return cp - str + 2; - if (cp[3] == 0) - return cp - str + 3; - if (sizeof (longword) > 4) - { - if (cp[4] == 0) - return cp - str + 4; - if (cp[5] == 0) - return cp - str + 5; - if (cp[6] == 0) - return cp - str + 6; - if (cp[7] == 0) - return cp - str + 7; - } - } - } + return ((const char *) word_ptr) + index_first_zero (word) - str; } +#ifndef STRLEN +weak_alias (__strlen, strlen) libc_hidden_builtin_def (strlen) +#endif diff --git a/sysdeps/s390/strlen-c.c b/sysdeps/s390/strlen-c.c index b829ef2452..0a33a6f8e5 100644 --- a/sysdeps/s390/strlen-c.c +++ b/sysdeps/s390/strlen-c.c @@ -21,12 +21,14 @@ #if HAVE_STRLEN_C # if HAVE_STRLEN_IFUNC # define STRLEN STRLEN_C -# if defined SHARED && IS_IN (libc) -# undef libc_hidden_builtin_def -# define libc_hidden_builtin_def(name) \ - __hidden_ver1 (__strlen_c, __GI_strlen, __strlen_c); -# endif # endif # include + +# if HAVE_STRLEN_IFUNC +# if defined SHARED && IS_IN (libc) +__hidden_ver1 (__strlen_c, __GI_strlen, __strlen_c); +# endif +# endif + #endif