| // Copyright (C) 2002, 2004, 2006 Free Software Foundation, Inc. |
| // |
| // This file is part of GCC. |
| // |
| // GCC 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 2, or (at your option) |
| // any later version. |
| |
| // GCC 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. |
| |
| // You should have received a copy of the GNU General Public License |
| // along with GCC; see the file COPYING. If not, write to |
| // the Free Software Foundation, 51 Franklin Street, Fifth Floor, |
| // Boston, MA 02110-1301, USA. |
| |
| // As a special exception, you may use this file as part of a free software |
| // library without restriction. Specifically, if other files instantiate |
| // templates or use macros or inline functions from this file, or you compile |
| // this file and link it with other files to produce an executable, this |
| // file does not by itself cause the resulting executable to be covered by |
| // the GNU General Public License. This exception does not however |
| // invalidate any other reasons why the executable file might be covered by |
| // the GNU General Public License. |
| |
| // Written by Mark Mitchell, CodeSourcery LLC, <mark@codesourcery.com> |
| // Thread support written by Jason Merrill, Red Hat Inc. <jason@redhat.com> |
| |
| #include <bits/c++config.h> |
| #include <cxxabi.h> |
| #include <exception> |
| #include <new> |
| #include <ext/atomicity.h> |
| #include <ext/concurrence.h> |
| |
| // The IA64/generic ABI uses the first byte of the guard variable. |
| // The ARM EABI uses the least significant bit. |
| |
| // Thread-safe static local initialization support. |
| #ifdef __GTHREADS |
| namespace |
| { |
| // A single mutex controlling all static initializations. |
| static __gnu_cxx::__recursive_mutex* static_mutex; |
| |
| typedef char fake_recursive_mutex[sizeof(__gnu_cxx::__recursive_mutex)] |
| __attribute__ ((aligned(__alignof__(__gnu_cxx::__recursive_mutex)))); |
| fake_recursive_mutex fake_mutex; |
| |
| static void init() |
| { static_mutex = new (&fake_mutex) __gnu_cxx::__recursive_mutex(); } |
| |
| __gnu_cxx::__recursive_mutex& |
| get_static_mutex() |
| { |
| static __gthread_once_t once = __GTHREAD_ONCE_INIT; |
| __gthread_once(&once, init); |
| return *static_mutex; |
| } |
| } |
| |
| #ifndef _GLIBCXX_GUARD_TEST_AND_ACQUIRE |
| inline bool |
| __test_and_acquire (__cxxabiv1::__guard *g) |
| { |
| bool b = _GLIBCXX_GUARD_TEST (g); |
| _GLIBCXX_READ_MEM_BARRIER; |
| return b; |
| } |
| #define _GLIBCXX_GUARD_TEST_AND_ACQUIRE(G) __test_and_acquire (G) |
| #endif |
| |
| #ifndef _GLIBCXX_GUARD_SET_AND_RELEASE |
| inline void |
| __set_and_release (__cxxabiv1::__guard *g) |
| { |
| _GLIBCXX_WRITE_MEM_BARRIER; |
| _GLIBCXX_GUARD_SET (g); |
| } |
| #define _GLIBCXX_GUARD_SET_AND_RELEASE(G) __set_and_release (G) |
| #endif |
| |
| #else /* !__GTHREADS */ |
| |
| #undef _GLIBCXX_GUARD_TEST_AND_ACQUIRE |
| #undef _GLIBCXX_GUARD_SET_AND_RELEASE |
| #define _GLIBCXX_GUARD_SET_AND_RELEASE(G) _GLIBCXX_GUARD_SET (G) |
| |
| #endif /* __GTHREADS */ |
| |
| namespace __gnu_cxx |
| { |
| // 6.7[stmt.dcl]/4: If control re-enters the declaration (recursively) |
| // while the object is being initialized, the behavior is undefined. |
| |
| // Since we already have a library function to handle locking, we might |
| // as well check for this situation and throw an exception. |
| // We use the second byte of the guard variable to remember that we're |
| // in the middle of an initialization. |
| class recursive_init_error: public std::exception |
| { |
| public: |
| recursive_init_error() throw() { } |
| virtual ~recursive_init_error() throw (); |
| }; |
| |
| recursive_init_error::~recursive_init_error() throw() { } |
| } |
| |
| namespace __cxxabiv1 |
| { |
| static inline int |
| recursion_push (__guard* g) |
| { return ((char *)g)[1]++; } |
| |
| static inline void |
| recursion_pop (__guard* g) |
| { --((char *)g)[1]; } |
| |
| static int |
| acquire (__guard *g) |
| { |
| if (_GLIBCXX_GUARD_TEST (g)) |
| return 0; |
| |
| if (recursion_push (g)) |
| { |
| #ifdef __EXCEPTIONS |
| throw __gnu_cxx::recursive_init_error(); |
| #else |
| // Use __builtin_trap so we don't require abort(). |
| __builtin_trap (); |
| #endif |
| } |
| return 1; |
| } |
| |
| extern "C" |
| int __cxa_guard_acquire (__guard *g) |
| { |
| #ifdef __GTHREADS |
| // If the target can reorder loads, we need to insert a read memory |
| // barrier so that accesses to the guarded variable happen after the |
| // guard test. |
| if (_GLIBCXX_GUARD_TEST_AND_ACQUIRE (g)) |
| return 0; |
| |
| if (__gthread_active_p ()) |
| { |
| // Simple wrapper for exception safety. |
| struct mutex_wrapper |
| { |
| bool unlock; |
| mutex_wrapper() : unlock(true) |
| { get_static_mutex().lock(); } |
| |
| ~mutex_wrapper() |
| { |
| if (unlock) |
| static_mutex->unlock(); |
| } |
| }; |
| |
| mutex_wrapper mw; |
| if (acquire (g)) |
| { |
| mw.unlock = false; |
| return 1; |
| } |
| |
| return 0; |
| } |
| #endif |
| |
| return acquire (g); |
| } |
| |
| extern "C" |
| void __cxa_guard_abort (__guard *g) |
| { |
| recursion_pop (g); |
| #ifdef __GTHREADS |
| if (__gthread_active_p ()) |
| static_mutex->unlock(); |
| #endif |
| } |
| |
| extern "C" |
| void __cxa_guard_release (__guard *g) |
| { |
| recursion_pop (g); |
| _GLIBCXX_GUARD_SET_AND_RELEASE (g); |
| #ifdef __GTHREADS |
| if (__gthread_active_p ()) |
| static_mutex->unlock(); |
| #endif |
| } |
| } |