From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 2181) id D42383857825; Thu, 2 Dec 2021 16:53:46 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org D42383857825 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset="utf-8" From: Jonathan Wakely To: gcc-cvs@gcc.gnu.org, libstdc++-cvs@gcc.gnu.org Subject: [gcc r12-5754] libstdc++: Remove broken std::allocator base classes [PR103340] X-Act-Checkin: gcc X-Git-Author: Jonathan Wakely X-Git-Refname: refs/heads/master X-Git-Oldrev: b5a568683f71b4a8b1e4e45a43484398e9a66ff2 X-Git-Newrev: e2e98f524fdb80c16e3395f20fee930fbcad5562 Message-Id: <20211202165346.D42383857825@sourceware.org> Date: Thu, 2 Dec 2021 16:53:46 +0000 (GMT) X-BeenThere: gcc-cvs@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gcc-cvs mailing list List-Unsubscribe: , List-Archive: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 02 Dec 2021 16:53:46 -0000 https://gcc.gnu.org/g:e2e98f524fdb80c16e3395f20fee930fbcad5562 commit r12-5754-ge2e98f524fdb80c16e3395f20fee930fbcad5562 Author: Jonathan Wakely Date: Wed Dec 1 16:30:30 2021 +0000 libstdc++: Remove broken std::allocator base classes [PR103340] The bitmap_allocator, __mt_alloc and __pool_alloc extensions are no longer suitable for use as the base class of std::allocator, because they have not been updated to meet the C++20 requirements. There is a patch attached to PR 103340 which addresses that, but more work would be needed to solve the linking errors that occur when the library is configured to use them. Using --enable-libstdcxx-allocator=bitmap wouldn't even bootstrap for the past few years, and I can't find any gcc-testresults reports using any of these allocators. This patch removes the configure option to use these as the std::allocator base class. The allocators are still in the tree and can be used directly, you just can't configure the library to use one of them as the base class of std::allocator. libstdc++-v3/ChangeLog: PR libstdc++/103340 PR libstdc++/103400 PR libstdc++/103381 * acinclude.m4 (GLIBCXX_ENABLE_ALLOCATOR): Remove mt, bitmap and pool options. * configure: Regenerate. * config/allocator/bitmap_allocator_base.h: Removed. * config/allocator/mt_allocator_base.h: Removed. * config/allocator/pool_allocator_base.h: Removed. * doc/xml/manual/allocator.xml: Update. * doc/xml/manual/configure.xml: Update. * doc/xml/manual/evolution.xml: Document removal. * doc/xml/manual/mt_allocator.xml: Editorial tweaks. * doc/html/manual/*: Regenerate. Diff: --- libstdc++-v3/acinclude.m4 | 14 +---- .../config/allocator/bitmap_allocator_base.h | 55 ------------------ libstdc++-v3/config/allocator/mt_allocator_base.h | 55 ------------------ .../config/allocator/pool_allocator_base.h | 55 ------------------ libstdc++-v3/configure | 14 +---- libstdc++-v3/doc/html/manual/api.html | 3 + libstdc++-v3/doc/html/manual/configure.html | 10 ++-- libstdc++-v3/doc/html/manual/memory.html | 57 ++++++------------ libstdc++-v3/doc/html/manual/mt_allocator.html | 8 +-- libstdc++-v3/doc/xml/manual/allocator.xml | 67 +++++++--------------- libstdc++-v3/doc/xml/manual/configure.xml | 10 ++-- libstdc++-v3/doc/xml/manual/evolution.xml | 5 ++ libstdc++-v3/doc/xml/manual/mt_allocator.xml | 8 +-- 13 files changed, 64 insertions(+), 297 deletions(-) diff --git a/libstdc++-v3/acinclude.m4 b/libstdc++-v3/acinclude.m4 index 71321055de7..6d9a8875e31 100644 --- a/libstdc++-v3/acinclude.m4 +++ b/libstdc++-v3/acinclude.m4 @@ -2599,7 +2599,7 @@ AC_DEFUN([GLIBCXX_ENABLE_ALLOCATOR], [ AC_MSG_CHECKING([for std::allocator base class]) GLIBCXX_ENABLE(libstdcxx-allocator,auto,[[[=KIND]]], [use KIND for target std::allocator base], - [permit new|malloc|mt|bitmap|pool|yes|no|auto]) + [permit new|malloc|yes|no|auto]) # If they didn't use this option switch, or if they specified --enable # with no specific model, we'll have to look for one. If they @@ -2631,26 +2631,14 @@ AC_DEFUN([GLIBCXX_ENABLE_ALLOCATOR], [ # Set configure bits for specified locale package case ${enable_libstdcxx_allocator_flag} in - bitmap) - ALLOCATOR_H=config/allocator/bitmap_allocator_base.h - ALLOCATOR_NAME=__gnu_cxx::bitmap_allocator - ;; malloc) ALLOCATOR_H=config/allocator/malloc_allocator_base.h ALLOCATOR_NAME=__gnu_cxx::malloc_allocator ;; - mt) - ALLOCATOR_H=config/allocator/mt_allocator_base.h - ALLOCATOR_NAME=__gnu_cxx::__mt_alloc - ;; new) ALLOCATOR_H=config/allocator/new_allocator_base.h ALLOCATOR_NAME=__gnu_cxx::new_allocator ;; - pool) - ALLOCATOR_H=config/allocator/pool_allocator_base.h - ALLOCATOR_NAME=__gnu_cxx::__pool_alloc - ;; esac GLIBCXX_CONDITIONAL(ENABLE_ALLOCATOR_NEW, diff --git a/libstdc++-v3/config/allocator/bitmap_allocator_base.h b/libstdc++-v3/config/allocator/bitmap_allocator_base.h deleted file mode 100644 index 40ccbf03449..00000000000 --- a/libstdc++-v3/config/allocator/bitmap_allocator_base.h +++ /dev/null @@ -1,55 +0,0 @@ -// Base to std::allocator -*- C++ -*- - -// Copyright (C) 2004-2021 Free Software Foundation, Inc. -// -// This file is part of the GNU ISO C++ Library. This library is free -// software; you can redistribute it and/or modify it under the -// terms of the GNU General Public License as published by the -// Free Software Foundation; either version 3, or (at your option) -// any later version. - -// This library is distributed in the hope that it will be useful, -// but WITHOUT ANY WARRANTY; without even the implied warranty of -// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the -// GNU General Public License for more details. - -// Under Section 7 of GPL version 3, you are granted additional -// permissions described in the GCC Runtime Library Exception, version -// 3.1, as published by the Free Software Foundation. - -// You should have received a copy of the GNU General Public License and -// a copy of the GCC Runtime Library Exception along with this program; -// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see -// . - -/** @file bits/c++allocator.h - * This is an internal header file, included by other library headers. - * Do not attempt to use it directly. @headername{memory} - */ - -#ifndef _GLIBCXX_CXX_ALLOCATOR_H -#define _GLIBCXX_CXX_ALLOCATOR_H 1 - -#include - -#if __cplusplus >= 201103L -namespace std -{ - /** - * @brief An alias to the base class for std::allocator. - * @ingroup allocators - * - * Used to set the std::allocator base class to - * __gnu_cxx::bitmap_allocator. - * - * @tparam _Tp Type of allocated object. - */ - template - using __allocator_base = __gnu_cxx::bitmap_allocator<_Tp>; -} -#else -// Define bitmap_allocator as the base class to std::allocator. -# define __allocator_base __gnu_cxx::bitmap_allocator -#endif - -#endif diff --git a/libstdc++-v3/config/allocator/mt_allocator_base.h b/libstdc++-v3/config/allocator/mt_allocator_base.h deleted file mode 100644 index eb45b8dea6d..00000000000 --- a/libstdc++-v3/config/allocator/mt_allocator_base.h +++ /dev/null @@ -1,55 +0,0 @@ -// Base to std::allocator -*- C++ -*- - -// Copyright (C) 2004-2021 Free Software Foundation, Inc. -// -// This file is part of the GNU ISO C++ Library. This library is free -// software; you can redistribute it and/or modify it under the -// terms of the GNU General Public License as published by the -// Free Software Foundation; either version 3, or (at your option) -// any later version. - -// This library is distributed in the hope that it will be useful, -// but WITHOUT ANY WARRANTY; without even the implied warranty of -// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the -// GNU General Public License for more details. - -// Under Section 7 of GPL version 3, you are granted additional -// permissions described in the GCC Runtime Library Exception, version -// 3.1, as published by the Free Software Foundation. - -// You should have received a copy of the GNU General Public License and -// a copy of the GCC Runtime Library Exception along with this program; -// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see -// . - -/** @file bits/c++allocator.h - * This is an internal header file, included by other library headers. - * Do not attempt to use it directly. @headername{memory} - */ - -#ifndef _GLIBCXX_CXX_ALLOCATOR_H -#define _GLIBCXX_CXX_ALLOCATOR_H 1 - -#include - -#if __cplusplus >= 201103L -namespace std -{ - /** - * @brief An alias to the base class for std::allocator. - * @ingroup allocators - * - * Used to set the std::allocator base class to - * __gnu_cxx::__mt_alloc. - * - * @tparam _Tp Type of allocated object. - */ - template - using __allocator_base = __gnu_cxx::__mt_alloc<_Tp>; -} -#else -// Define __mt_alloc as the base class to std::allocator. -# define __allocator_base __gnu_cxx::__mt_alloc -#endif - -#endif diff --git a/libstdc++-v3/config/allocator/pool_allocator_base.h b/libstdc++-v3/config/allocator/pool_allocator_base.h deleted file mode 100644 index c3ec8ecce8d..00000000000 --- a/libstdc++-v3/config/allocator/pool_allocator_base.h +++ /dev/null @@ -1,55 +0,0 @@ -// Base to std::allocator -*- C++ -*- - -// Copyright (C) 2004-2021 Free Software Foundation, Inc. -// -// This file is part of the GNU ISO C++ Library. This library is free -// software; you can redistribute it and/or modify it under the -// terms of the GNU General Public License as published by the -// Free Software Foundation; either version 3, or (at your option) -// any later version. - -// This library is distributed in the hope that it will be useful, -// but WITHOUT ANY WARRANTY; without even the implied warranty of -// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the -// GNU General Public License for more details. - -// Under Section 7 of GPL version 3, you are granted additional -// permissions described in the GCC Runtime Library Exception, version -// 3.1, as published by the Free Software Foundation. - -// You should have received a copy of the GNU General Public License and -// a copy of the GCC Runtime Library Exception along with this program; -// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see -// . - -/** @file bits/c++allocator.h - * This is an internal header file, included by other library headers. - * Do not attempt to use it directly. @headername{memory} - */ - -#ifndef _GLIBCXX_CXX_ALLOCATOR_H -#define _GLIBCXX_CXX_ALLOCATOR_H 1 - -#include - -#if __cplusplus >= 201103L -namespace std -{ - /** - * @brief An alias to the base class for std::allocator. - * @ingroup allocators - * - * Used to set the std::allocator base class to - * __gnu_cxx::__pool_alloc. - * - * @tparam _Tp Type of allocated object. - */ - template - using __allocator_base = __gnu_cxx::__pool_alloc<_Tp>; -} -#else -// Define __pool_alloc as the base class to std::allocator. -# define __allocator_base __gnu_cxx::__pool_alloc -#endif - -#endif diff --git a/libstdc++-v3/configure b/libstdc++-v3/configure index 9049e4b9864..61a14a2cb3b 100755 --- a/libstdc++-v3/configure +++ b/libstdc++-v3/configure @@ -16848,7 +16848,7 @@ $as_echo_n "checking for std::allocator base class... " >&6; } if test "${enable_libstdcxx_allocator+set}" = set; then : enableval=$enable_libstdcxx_allocator; case "$enableval" in - new|malloc|mt|bitmap|pool|yes|no|auto) ;; + new|malloc|yes|no|auto) ;; *) as_fn_error $? "Unknown argument to enable/disable libstdcxx-allocator" "$LINENO" 5 ;; esac @@ -16889,26 +16889,14 @@ $as_echo "$enable_libstdcxx_allocator_flag" >&6; } # Set configure bits for specified locale package case ${enable_libstdcxx_allocator_flag} in - bitmap) - ALLOCATOR_H=config/allocator/bitmap_allocator_base.h - ALLOCATOR_NAME=__gnu_cxx::bitmap_allocator - ;; malloc) ALLOCATOR_H=config/allocator/malloc_allocator_base.h ALLOCATOR_NAME=__gnu_cxx::malloc_allocator ;; - mt) - ALLOCATOR_H=config/allocator/mt_allocator_base.h - ALLOCATOR_NAME=__gnu_cxx::__mt_alloc - ;; new) ALLOCATOR_H=config/allocator/new_allocator_base.h ALLOCATOR_NAME=__gnu_cxx::new_allocator ;; - pool) - ALLOCATOR_H=config/allocator/pool_allocator_base.h - ALLOCATOR_NAME=__gnu_cxx::__pool_alloc - ;; esac diff --git a/libstdc++-v3/doc/html/manual/api.html b/libstdc++-v3/doc/html/manual/api.html index 32810788bf2..2cc44aed4e3 100644 --- a/libstdc++-v3/doc/html/manual/api.html +++ b/libstdc++-v3/doc/html/manual/api.html @@ -444,4 +444,7 @@ can be used instead. The std::unexpected function and related typedef and accessors for the unexpected handler are deprecated for C++11 and later. Dynamic exception specifications should be replaced with noexcept. +

+The bitmap, mt, and pool +options for --enable-libstdcxx-allocator were removed.

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ABI Policy and Guidelines Home Backwards Compatibility
\ No newline at end of file diff --git a/libstdc++-v3/doc/html/manual/configure.html b/libstdc++-v3/doc/html/manual/configure.html index 9e2e9dcb18e..31c4da8a5e3 100644 --- a/libstdc++-v3/doc/html/manual/configure.html +++ b/libstdc++-v3/doc/html/manual/configure.html @@ -64,12 +64,10 @@ '--enable-libstdcxx-allocator=auto' (described next).

--enable-libstdcxx-allocator=OPTION

Select a target-specific underlying std::allocator. The - choices are 'new' to specify a wrapper for new, 'malloc' to - specify a wrapper for malloc, 'mt' for a fixed power of two allocator, - 'pool' for the SGI pooled allocator or 'bitmap' for a bitmap allocator. - See this page for more information on allocator - extensions. This option - can change the library ABI. + choices are 'new' to specify a wrapper for new, and 'malloc' to + specify a wrapper for malloc. + See the section called “Extension Allocators” for more information. + This option can change the library ABI.

--enable-cheaders=OPTION

This allows the user to define the approach taken for C header compatibility with C++. Options are c, c_std, and c_global. These correspond to the source directory's include/c, diff --git a/libstdc++-v3/doc/html/manual/memory.html b/libstdc++-v3/doc/html/manual/memory.html index 5b28a5a9763..1681d9853b0 100644 --- a/libstdc++-v3/doc/html/manual/memory.html +++ b/libstdc++-v3/doc/html/manual/memory.html @@ -103,8 +103,9 @@ high-speed extension allocators, covered below. Thus, all allocation and deallocation depends on the base class.

- The base class that allocator is derived from - may not be user-configurable. + The choice of base class that allocator + is derived from is fixed at the time when GCC is built, + and the different choices are not ABI compatible.

Selecting Default Allocation Policy

It's difficult to pick an allocation strategy that will provide maximum utility, without excessively penalizing some behavior. In @@ -198,6 +199,10 @@ Probably the best place to start would be to copy one of the extension allocators: say a simple one like new_allocator. +

+ Since C++11 the minimal interface require for an allocator is + much smaller, as std::allocator_traits + can provide default for much of the interface.

Extension Allocators

Several other allocators are provided as part of this implementation. The location of the extension allocators and their @@ -224,9 +229,10 @@

  • debug_allocator

    - A wrapper around an arbitrary allocator A. It passes on - slightly increased size requests to A, and uses the extra - memory to store size information. When a pointer is passed + A wrapper around an arbitrary allocator A. + It passes on slightly increased size requests to A, + and uses the extra memory to store size information. + When a pointer is passed to deallocate(), the stored size is checked, and assert() is used to guarantee they match. @@ -248,41 +254,14 @@ request is passed to ::operator new directly.

    - Older versions of this class take a boolean template - parameter, called thr, and an integer template - parameter, called inst. + For thread-enabled configurations, the pool is locked with a + single big lock. In some situations, this implementation detail + may result in severe performance degradation.

    - The inst number is used to track additional memory - pools. The point of the number is to allow multiple - instantiations of the classes without changing the semantics at - all. All three of - 

    -    typedef  __pool_alloc<true,0>    normal;
-    typedef  __pool_alloc<true,1>    private;
-    typedef  __pool_alloc<true,42>   also_private;
-

    - behave exactly the same way. However, the memory pool for each type - (and remember that different instantiations result in different types) - remains separate. -

    - The library uses 0 in all its instantiations. If you - wish to keep separate free lists for a particular purpose, use a - different number. -

    The thr boolean determines whether the - pool should be manipulated atomically or not. When - thr = true, the allocator - is thread-safe, while thr = - false, is slightly faster but unsafe for - multiple threads. -

    - For thread-enabled configurations, the pool is locked with a - single big lock. In some situations, this implementation detail - may result in severe performance degradation. -

    - (Note that the GCC thread abstraction layer allows us to provide - safe zero-overhead stubs for the threading routines, if threads - were disabled at configuration time.) -

  • + (Note that the GCC thread abstraction layer allows us to provide + safe zero-overhead stubs for the threading routines, if threads + were disabled at configuration time.) +

  • __mt_alloc

    A high-performance fixed-size allocator with diff --git a/libstdc++-v3/doc/html/manual/mt_allocator.html b/libstdc++-v3/doc/html/manual/mt_allocator.html index c7786f02844..68e7dccde78 100644 --- a/libstdc++-v3/doc/html/manual/mt_allocator.html +++ b/libstdc++-v3/doc/html/manual/mt_allocator.html @@ -6,12 +6,12 @@

    Intro

    The mt allocator [hereinafter referred to simply as "the allocator"] is a fixed size (power of two) allocator that was initially - developed specifically to suit the needs of multi threaded + developed specifically to suit the needs of multi-threaded applications [hereinafter referred to as an MT application]. Over time the allocator has evolved and been improved in many ways, in - particular it now also does a good job in single threaded - applications [hereinafter referred to as a ST application]. (Note: - In this document, when referring to single threaded applications + particular it now also does a good job in single-threaded + applications [hereinafter referred to as an ST application]. (Note: + In this document, when referring to single-threaded applications this also includes applications that are compiled with gcc without thread support enabled. This is accomplished using ifdef's on __GTHREADS). This allocator is tunable, very flexible, and capable diff --git a/libstdc++-v3/doc/xml/manual/allocator.xml b/libstdc++-v3/doc/xml/manual/allocator.xml index 1f429410eb0..aaab4e29aa7 100644 --- a/libstdc++-v3/doc/xml/manual/allocator.xml +++ b/libstdc++-v3/doc/xml/manual/allocator.xml @@ -154,8 +154,9 @@ - The base class that allocator is derived from - may not be user-configurable. + The choice of base class that allocator + is derived from is fixed at the time when GCC is built, + and the different choices are not ABI compatible. @@ -314,6 +315,13 @@ new_allocator. + + Since C++11 the minimal interface require for an allocator is + much smaller, as std::allocator_traits + can provide default for much of the interface. + + +

    Extension Allocators @@ -359,9 +367,10 @@ debug_allocator - A wrapper around an arbitrary allocator A. It passes on - slightly increased size requests to A, and uses the extra - memory to store size information. When a pointer is passed + A wrapper around an arbitrary allocator A. + It passes on slightly increased size requests to A, + and uses the extra memory to store size information. + When a pointer is passed to deallocate(), the stored size is checked, and assert() is used to guarantee they match. @@ -393,52 +402,16 @@ - Older versions of this class take a boolean template - parameter, called thr, and an integer template - parameter, called inst. + For thread-enabled configurations, the pool is locked with a + single big lock. In some situations, this implementation detail + may result in severe performance degradation. - The inst number is used to track additional memory - pools. The point of the number is to allow multiple - instantiations of the classes without changing the semantics at - all. All three of + (Note that the GCC thread abstraction layer allows us to provide + safe zero-overhead stubs for the threading routines, if threads + were disabled at configuration time.) - - - typedef __pool_alloc<true,0> normal; - typedef __pool_alloc<true,1> private; - typedef __pool_alloc<true,42> also_private; - - - behave exactly the same way. However, the memory pool for each type - (and remember that different instantiations result in different types) - remains separate. - - - The library uses 0 in all its instantiations. If you - wish to keep separate free lists for a particular purpose, use a - different number. - - The thr boolean determines whether the - pool should be manipulated atomically or not. When - thr = true, the allocator - is thread-safe, while thr = - false, is slightly faster but unsafe for - multiple threads. - - - - For thread-enabled configurations, the pool is locked with a - single big lock. In some situations, this implementation detail - may result in severe performance degradation. - - - - (Note that the GCC thread abstraction layer allows us to provide - safe zero-overhead stubs for the threading routines, if threads - were disabled at configuration time.) - diff --git a/libstdc++-v3/doc/xml/manual/configure.xml b/libstdc++-v3/doc/xml/manual/configure.xml index cc9c8554c6c..8c26acc95a7 100644 --- a/libstdc++-v3/doc/xml/manual/configure.xml +++ b/libstdc++-v3/doc/xml/manual/configure.xml @@ -118,12 +118,10 @@ --enable-libstdcxx-allocator=OPTION Select a target-specific underlying std::allocator. The - choices are 'new' to specify a wrapper for new, 'malloc' to - specify a wrapper for malloc, 'mt' for a fixed power of two allocator, - 'pool' for the SGI pooled allocator or 'bitmap' for a bitmap allocator. - See this page for more information on allocator - extensions. This option - can change the library ABI. + choices are 'new' to specify a wrapper for new, and 'malloc' to + specify a wrapper for malloc. + See for more information. + This option can change the library ABI. diff --git a/libstdc++-v3/doc/xml/manual/evolution.xml b/libstdc++-v3/doc/xml/manual/evolution.xml index 9aef84a0933..271d2225c3a 100644 --- a/libstdc++-v3/doc/xml/manual/evolution.xml +++ b/libstdc++-v3/doc/xml/manual/evolution.xml @@ -1033,6 +1033,11 @@ accessors for the unexpected handler are deprecated for C++11 and later. Dynamic exception specifications should be replaced with noexcept. + +The bitmap, mt, and pool +options for were removed. + +
    diff --git a/libstdc++-v3/doc/xml/manual/mt_allocator.xml b/libstdc++-v3/doc/xml/manual/mt_allocator.xml index 93504a7d711..f1c09b3bd8f 100644 --- a/libstdc++-v3/doc/xml/manual/mt_allocator.xml +++ b/libstdc++-v3/doc/xml/manual/mt_allocator.xml @@ -20,12 +20,12 @@ The mt allocator [hereinafter referred to simply as "the allocator"] is a fixed size (power of two) allocator that was initially - developed specifically to suit the needs of multi threaded + developed specifically to suit the needs of multi-threaded applications [hereinafter referred to as an MT application]. Over time the allocator has evolved and been improved in many ways, in - particular it now also does a good job in single threaded - applications [hereinafter referred to as a ST application]. (Note: - In this document, when referring to single threaded applications + particular it now also does a good job in single-threaded + applications [hereinafter referred to as an ST application]. (Note: + In this document, when referring to single-threaded applications this also includes applications that are compiled with gcc without thread support enabled. This is accomplished using ifdef's on __GTHREADS). This allocator is tunable, very flexible, and capable