From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from nikam.ms.mff.cuni.cz (nikam.ms.mff.cuni.cz [195.113.20.16]) by sourceware.org (Postfix) with ESMTPS id ED1893858C33; Wed, 28 Jun 2023 07:56:13 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org ED1893858C33 Authentication-Results: sourceware.org; dmarc=fail (p=none dis=none) header.from=ucw.cz Authentication-Results: sourceware.org; spf=none smtp.mailfrom=kam.mff.cuni.cz Received: by nikam.ms.mff.cuni.cz (Postfix, from userid 16202) id 28B33281AB9; Wed, 28 Jun 2023 09:56:12 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ucw.cz; s=gen1; t=1687938972; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=Tu8go17pqxelb9aA9MxyMduCfXNNHHtUQkMGI8P8T2E=; b=GsZdKeozgNt7jEX8loEJs1ZV1P3UfqTKRKQhsIvlB4f1B56IpSOi9+f6dmr1PcGtQxCCn1 elQJK9aZgC8vtyVjbeTp3aOKxbUDPXMSnXuCucCjqBSvaICkn+06kr2g3//CNwQMrh6o/u 0dNmOyulBkpdpIqBpDkAmYwpUeRzV0c= Date: Wed, 28 Jun 2023 09:56:12 +0200 From: Jan Hubicka To: Jonathan Wakely Cc: libstdc++@gcc.gnu.org, gcc-patches@gcc.gnu.org Subject: Re: [PATCH] libstdc++: Use RAII in std::vector::_M_realloc_insert Message-ID: References: <20230620133858.166497-1-jwakely@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Spam-Status: No, score=-11.2 required=5.0 tests=BAYES_00,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,GIT_PATCH_0,HEADER_FROM_DIFFERENT_DOMAINS,RCVD_IN_MSPIKE_H3,RCVD_IN_MSPIKE_WL,SPF_HELO_NONE,SPF_NONE,TXREP,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: > I think the __throw_bad_alloc() and __throw_bad_array_new_length() > functions should always be rare, so marking them cold seems fine (users who > define their own allocators that want to throw bad_alloc "often" will > probably throw it directly, they shouldn't be using our __throw_bad_alloc() > function anyway). I don't think __throw_bad_exception is ever used, so that > doesn't matter (we could remove it from the header and just keep its > definition in the library, but there's no big advantage to doing that). > Others like __throw_length_error() should also be very very rare, and could > be marked cold. > > Maybe we should just mark everything in as cold. If > users want to avoid the cost of calls to those functions they can do so by > checking function preconditions/arguments to avoid the exceptions. There > are very few places where a throwing libstdc++ API doesn't have a way to > avoid the exception. The only one that isn't easily avoidable is > __throw_bad_alloc but OOM should be rare. Hi, this marks everything in functexcept.h as cold and I also noticed that we probably want to mark as such terminate. With fix to 110436 and -O3 we now inline _M_realloc_insert, yay :) tested on x86_64-linux, OK? * include/bits/c++config (std::__terminate): Mark cold. * include/bits/functexcept.h: Mark everything as cold. * libsupc++/exception: Mark terminate and unexpected as cold. diff --git a/libstdc++-v3/include/bits/c++config b/libstdc++-v3/include/bits/c++config index 009a017b048..dd47f274d5f 100644 --- a/libstdc++-v3/include/bits/c++config +++ b/libstdc++-v3/include/bits/c++config @@ -320,7 +320,7 @@ namespace std extern "C++" __attribute__ ((__noreturn__, __always_inline__)) inline void __terminate() _GLIBCXX_USE_NOEXCEPT { - void terminate() _GLIBCXX_USE_NOEXCEPT __attribute__ ((__noreturn__)); + void terminate() _GLIBCXX_USE_NOEXCEPT __attribute__ ((__noreturn__,__cold__)); terminate(); } #pragma GCC visibility pop diff --git a/libstdc++-v3/include/bits/functexcept.h b/libstdc++-v3/include/bits/functexcept.h index 2765f7865df..a2e97413661 100644 --- a/libstdc++-v3/include/bits/functexcept.h +++ b/libstdc++-v3/include/bits/functexcept.h @@ -57,61 +57,61 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION // Helper for exception objects in void - __throw_bad_cast(void) __attribute__((__noreturn__)); + __throw_bad_cast(void) __attribute__((__noreturn__,__cold__)); void - __throw_bad_typeid(void) __attribute__((__noreturn__)); + __throw_bad_typeid(void) __attribute__((__noreturn__,__cold__)); // Helpers for exception objects in void - __throw_logic_error(const char*) __attribute__((__noreturn__)); + __throw_logic_error(const char*) __attribute__((__noreturn__,__cold__)); void - __throw_domain_error(const char*) __attribute__((__noreturn__)); + __throw_domain_error(const char*) __attribute__((__noreturn__,__cold__)); void - __throw_invalid_argument(const char*) __attribute__((__noreturn__)); + __throw_invalid_argument(const char*) __attribute__((__noreturn__,__cold__)); void - __throw_length_error(const char*) __attribute__((__noreturn__)); + __throw_length_error(const char*) __attribute__((__noreturn__,__cold__)); void - __throw_out_of_range(const char*) __attribute__((__noreturn__)); + __throw_out_of_range(const char*) __attribute__((__noreturn__,__cold__)); void - __throw_out_of_range_fmt(const char*, ...) __attribute__((__noreturn__)) + __throw_out_of_range_fmt(const char*, ...) __attribute__((__noreturn__,__cold__)) __attribute__((__format__(__gnu_printf__, 1, 2))); void - __throw_runtime_error(const char*) __attribute__((__noreturn__)); + __throw_runtime_error(const char*) __attribute__((__noreturn__,__cold__)); void - __throw_range_error(const char*) __attribute__((__noreturn__)); + __throw_range_error(const char*) __attribute__((__noreturn__,__cold__)); void - __throw_overflow_error(const char*) __attribute__((__noreturn__)); + __throw_overflow_error(const char*) __attribute__((__noreturn__,__cold__)); void - __throw_underflow_error(const char*) __attribute__((__noreturn__)); + __throw_underflow_error(const char*) __attribute__((__noreturn__,__cold__)); // Helpers for exception objects in void - __throw_ios_failure(const char*) __attribute__((__noreturn__)); + __throw_ios_failure(const char*) __attribute__((__noreturn__,__cold__)); void - __throw_ios_failure(const char*, int) __attribute__((__noreturn__)); + __throw_ios_failure(const char*, int) __attribute__((__noreturn__,__cold__)); // Helpers for exception objects in void - __throw_system_error(int) __attribute__((__noreturn__)); + __throw_system_error(int) __attribute__((__noreturn__,__cold__)); // Helpers for exception objects in void - __throw_future_error(int) __attribute__((__noreturn__)); + __throw_future_error(int) __attribute__((__noreturn__,__cold__)); // Helpers for exception objects in void - __throw_bad_function_call() __attribute__((__noreturn__)); + __throw_bad_function_call() __attribute__((__noreturn__,__cold__)); #else // ! HOSTED diff --git a/libstdc++-v3/libsupc++/exception b/libstdc++-v3/libsupc++/exception index a34386e6026..00a6347ebe5 100644 --- a/libstdc++-v3/libsupc++/exception +++ b/libstdc++-v3/libsupc++/exception @@ -75,7 +75,7 @@ namespace std _GLIBCXX_VISIBILITY(default) /** The runtime will call this function if %exception handling must be * abandoned for any reason. It can also be called by the user. */ - void terminate() _GLIBCXX_USE_NOEXCEPT __attribute__ ((__noreturn__)); + void terminate() _GLIBCXX_USE_NOEXCEPT __attribute__ ((__noreturn__,__cold__)); #if __cplusplus < 201703L || (__cplusplus <= 202002L && _GLIBCXX_USE_DEPRECATED) /// If you write a replacement %unexpected handler, it must be of this type. @@ -104,7 +104,7 @@ namespace std _GLIBCXX_VISIBILITY(default) * @deprecated Removed from the C++ standard in C++17 */ _GLIBCXX11_DEPRECATED - void unexpected() __attribute__ ((__noreturn__)); + void unexpected() __attribute__ ((__noreturn__,__cold__)); #endif /** [18.6.4]/1: 'Returns true after completing evaluation of a