From patchwork Fri Oct 28 11:08:46 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pedro Alves X-Patchwork-Id: 59575 Return-Path: X-Original-To: patchwork@sourceware.org Delivered-To: patchwork@sourceware.org Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id E76B1385D0C2 for ; Fri, 28 Oct 2022 11:09:05 +0000 (GMT) X-Original-To: gdb-patches@sourceware.org Delivered-To: gdb-patches@sourceware.org Received: from mail-wr1-f48.google.com (mail-wr1-f48.google.com [209.85.221.48]) by sourceware.org (Postfix) with ESMTPS id 54F353857C63 for ; Fri, 28 Oct 2022 11:08:49 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 54F353857C63 Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=palves.net Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=gmail.com Received: by mail-wr1-f48.google.com with SMTP id bk15so6107843wrb.13 for ; Fri, 28 Oct 2022 04:08:49 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:content-language:in-reply-to:mime-version :user-agent:date:message-id:references:to:from:subject :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=t0vMs5Ve/Az/vtwk8OHjFIozoxOTRrDc0LwkAlfXQDs=; b=taNbJXj3kyyZxdmJiKWYAC8NsRZEZR8qnhk6YltbUFEipWCxADK8KP8HMDbHGvFHVw Cjnf3YHcVODKhHszcWileLA4SuzpxbUcOxiHMN8aC+/hq0UBOhfog+x/y++UXAnoKRVx roXHtCy025WnSOb/QZtrAfPDtbIZ2oz0CB2XuyR2c8plqiRhPaOhFzHv9+XfO3LrOZv6 iT60/1TW17ptljAeTqILxAi7xQi3Rq+XF5orOUz4tICTQ2Db0pTYFEVp6DQe6L7LM7UD kfEu+CioOmWlZ/tQt5nL1NKte8aPaizvgHp0F0togwDaMIEIQCZH0EVj4EsgTr/OOvMj KYKw== X-Gm-Message-State: ACrzQf16Ru3fZ7RmSVeHNAQu7VFIIwuxswjYuBQW2e9v/o3Yii0qc1X4 Lvs6tlUkBzgjyK27MJ7fjVYwMZH4W0hfug== X-Google-Smtp-Source: AMsMyM4KpGL01sj4oDcocdFJeBwVjed/xOk49db37pHNeMrm98ngQ/ZSXEr2s1lLgaL/bxLHEX2tWg== X-Received: by 2002:a5d:4692:0:b0:235:b188:3ec with SMTP id u18-20020a5d4692000000b00235b18803ecmr28899421wrq.210.1666955327890; Fri, 28 Oct 2022 04:08:47 -0700 (PDT) Received: from ?IPv6:2001:8a0:f93a:3b00:e038:5cdc:b8bf:4653? ([2001:8a0:f93a:3b00:e038:5cdc:b8bf:4653]) by smtp.gmail.com with ESMTPSA id bg35-20020a05600c3ca300b003c65c9a36dfsm4311938wmb.48.2022.10.28.04.08.47 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 28 Oct 2022 04:08:47 -0700 (PDT) Subject: [PATCH v3] enum_flags to_string (was: Re: [PATCH v2 07/29] Thread options & clone events (core + remote)) From: Pedro Alves To: Simon Marchi , gdb-patches@sourceware.org References: <20220713222433.374898-1-pedro@palves.net> <20220713222433.374898-8-pedro@palves.net> <5d68cd36-e8d6-e8ad-5428-863e79742062@simark.ca> Message-ID: <6b91f8f6-d3b5-c44b-297c-ce1c3a1c80f6@palves.net> Date: Fri, 28 Oct 2022 12:08:46 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.10.1 MIME-Version: 1.0 In-Reply-To: Content-Language: en-US X-Spam-Status: No, score=-10.1 required=5.0 tests=BAYES_00, FREEMAIL_FORGED_FROMDOMAIN, FREEMAIL_FROM, GIT_PATCH_0, HEADER_FROM_DIFFERENT_DOMAINS, KAM_DMARC_STATUS, RCVD_IN_DNSWL_NONE, RCVD_IN_MSPIKE_H2, 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: gdb-patches@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gdb-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: gdb-patches-bounces+patchwork=sourceware.org@sourceware.org Sender: "Gdb-patches" On 2022-10-28 11:26 a.m., Pedro Alves wrote: > Some self review. :-) > > On 2022-10-27 8:55 p.m., Pedro Alves wrote: > >> >> static std::string >> to_string (some_flags flags) >> { >> #define CASE(X) { X, #X } >> static constexpr test_flags::string_map_element mapping[] = { >> CASE (SOME_FLAG1), >> CASE (SOME_FLAG2), >> CASE (SOME_FLAG3), >> }; >> #undef CASE >> >> return flags.to_string (mapping); >> } > > I was looking at this again, and noticed I named the macro "CASE". That's just > because that style of macro is typically used in a switch/case, my first approach > used one. That isn't what's being done in the end, so better rename it. And while doing that, > I realized that you don't even need to name the array or its type. Like so: > > static std::string > to_string (some_flags flags) > { > #define MAP_ENUM_FLAG(X) { X, #X } > return flags.to_string ({ > MAP_ENUM_FLAG (SOME_FLAG1), > MAP_ENUM_FLAG (SOME_FLAG3), > }); > #undef MAP_ENUM_FLAG > } > > But then, every enum_flags to_string implementation will end up defining/undefining that > same macro, so might as well put it in gdbsupport/enum-flags.h, resulting in: > > static std::string > to_string (test_flags flags) > { > return flags.to_string ({ > MAP_ENUM_FLAG (FLAG1), > MAP_ENUM_FLAG (FLAG3), > }); > } Bah, I now looked at the generated code at -O2, and with the unnamed array, the compiler emits code to manually compose a temporary array on the stack at every call... 3rd time's a charm? -- >8 -- From 0fe3edef69360c6795ab6811c4f3cba06159a50d Mon Sep 17 00:00:00 2001 From: Pedro Alves Date: Tue, 25 Oct 2022 15:39:37 +0100 Subject: [PATCH] enum_flags to_string This commit introduces shared infrastructure that can be used to implement enum_flags -> to_string functions. With this, if we want to support converting a given enum_flags specialization to string, we just need to implement a function that provides the enumerator->string mapping, like so: enum some_flag { SOME_FLAG1 = 1 << 0, SOME_FLAG2 = 1 << 1, SOME_FLAG3 = 1 << 2, }; DEF_ENUM_FLAGS_TYPE (some_flag, some_flags); static std::string to_string (some_flags flags) { static constexpr some_flags::string_mapping mapping[] = { MAP_ENUM_FLAG (SOME_FLAG1), MAP_ENUM_FLAG (SOME_FLAG2), MAP_ENUM_FLAG (SOME_FLAG3), }; return flags.to_string (mapping); } .. and then to_string(SOME_FLAG2 | SOME_FLAG3) produces a string like "0x6 [SOME_FLAG2 SOME_FLAG3]". If we happen to forget to update the mapping array when we introduce a new enumerator, then the string representation will pretty-print the flags it knows about, and then the leftover flags in hex (one single number). For example, if we had missed mapping SOME_FLAG2 above, we'd end up with: to_string(SOME_FLAG2 | SOME_FLAG3) => "0x6 [SOME_FLAG2 0x4]"); Other than in the unit tests included, no actual usage of the functionality is added in this commit. Change-Id: I835de43c33d13bc0c95132f42c3f97318b875779 --- gdb/unittests/enum-flags-selftests.c | 24 ++++++++++++ gdbsupport/enum-flags.h | 57 ++++++++++++++++++++++++++++ 2 files changed, 81 insertions(+) base-commit: 508ccf9b3e1db355037a4a1c9004efe0d6d3ffbf diff --git a/gdb/unittests/enum-flags-selftests.c b/gdb/unittests/enum-flags-selftests.c index f52fc7220a1..ef43ba23cdf 100644 --- a/gdb/unittests/enum-flags-selftests.c +++ b/gdb/unittests/enum-flags-selftests.c @@ -374,6 +374,20 @@ enum test_uflag : unsigned DEF_ENUM_FLAGS_TYPE (test_flag, test_flags); DEF_ENUM_FLAGS_TYPE (test_uflag, test_uflags); +/* to_string enumerator->string mapping function used to test + enum_flags::to_string. This intentionally misses mapping one + enumerator (FLAG2). */ + +static std::string +to_string (test_flags flags) +{ + static constexpr test_flags::string_mapping mapping[] = { + MAP_ENUM_FLAG (FLAG1), + MAP_ENUM_FLAG (FLAG3), + }; + return flags.to_string (mapping); +} + static void self_test () { @@ -581,6 +595,16 @@ self_test () SELF_CHECK (ok); } + + /* Check string conversion. */ + { + SELF_CHECK (to_string (0) == "0x0 []"); + SELF_CHECK (to_string (FLAG1) == "0x2 [FLAG1]"); + SELF_CHECK (to_string (FLAG1 | FLAG3) == "0xa [FLAG1 FLAG3]"); + SELF_CHECK (to_string (FLAG1 | FLAG2 | FLAG3) == "0xe [FLAG1 FLAG3 0x4]"); + SELF_CHECK (to_string (FLAG2) == "0x4 [0x4]"); + SELF_CHECK (to_string (test_flag (0xff)) == "0xff [FLAG1 FLAG3 0xf5]"); + } } } /* namespace enum_flags_tests */ diff --git a/gdbsupport/enum-flags.h b/gdbsupport/enum-flags.h index cd500f55ff3..911f3fd7890 100644 --- a/gdbsupport/enum-flags.h +++ b/gdbsupport/enum-flags.h @@ -130,6 +130,17 @@ class enum_flags typedef E enum_type; typedef typename enum_underlying_type::type underlying_type; + /* For to_string. Maps one enumerator of E to a string. */ + struct string_mapping + { + E flag; + const char *str; + }; + + /* Convenience for to_string implementations, to build a + string_mapping array. */ +#define MAP_ENUM_FLAG(ENUM_FLAG) { ENUM_FLAG, #ENUM_FLAG } + public: /* Allow default construction. */ constexpr enum_flags () @@ -183,6 +194,52 @@ class enum_flags /* Binary operations involving some unrelated type (which would be a bug) are implemented as non-members, and deleted. */ + /* Convert this object to a std::string, using MAPPING as + enumerator-to-string mapping array. This is not meant to be + called directly. Instead, enum_flags specializations should have + their own to_string function wrapping this one, thus hidding the + mapping array from callers. */ + + template + std::string + to_string (const string_mapping (&mapping)[N]) const + { + enum_type flags = raw (); + std::string res = hex_string (flags); + res += " ["; + + bool need_space = false; + for (const auto &entry : mapping) + { + if ((flags & entry.flag) != 0) + { + /* Do op~ in the underlying type, because if enum_type's + underlying type is signed, op~ won't be defined for + it. */ + flags &= (enum_type) ~(underlying_type) entry.flag; + + if (need_space) + res += " "; + res += entry.str; + + need_space = true; + } + } + + /* If there were flags not included in the mapping, print them as + a hex number. */ + if (flags != 0) + { + if (need_space) + res += " "; + res += hex_string (flags); + } + + res += "]"; + + return res; + } + private: /* Stored as enum_type because GDB knows to print the bit flags neatly if the enum values look like bit flags. */