1  // Control various target specific ABI tweaks.  ARM version.
       2  
       3  // Copyright (C) 2004-2023 Free Software Foundation, Inc.
       4  //
       5  // This file is part of the GNU ISO C++ Library.  This library is free
       6  // software; you can redistribute it and/or modify it under the
       7  // terms of the GNU General Public License as published by the
       8  // Free Software Foundation; either version 3, or (at your option)
       9  // any later version.
      10  
      11  // This library is distributed in the hope that it will be useful,
      12  // but WITHOUT ANY WARRANTY; without even the implied warranty of
      13  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      14  // GNU General Public License for more details.
      15  
      16  // Under Section 7 of GPL version 3, you are granted additional
      17  // permissions described in the GCC Runtime Library Exception, version
      18  // 3.1, as published by the Free Software Foundation.
      19  
      20  // You should have received a copy of the GNU General Public License and
      21  // a copy of the GCC Runtime Library Exception along with this program;
      22  // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
      23  // <http://www.gnu.org/licenses/>.
      24  
      25  /** @file bits/cxxabi_tweaks.h
      26   *  This is an internal header file, included by other library headers.
      27   *  Do not attempt to use it directly. @headername{cxxabi.h}
      28   */
      29  
      30  #ifndef _CXXABI_TWEAKS_H
      31  #define _CXXABI_TWEAKS_H 1
      32  
      33  #ifdef __cplusplus
      34  namespace __cxxabiv1
      35  {
      36    extern "C"
      37    {
      38  #endif
      39  
      40  #ifdef __ARM_EABI__
      41    // The ARM EABI uses the least significant bit of a 32-bit
      42    // guard variable.
      43  #define _GLIBCXX_GUARD_TEST(x) ((*(x) & 1) != 0)
      44  #define _GLIBCXX_GUARD_SET(x) *(x) = 1
      45  #define _GLIBCXX_GUARD_BIT 1
      46  #define _GLIBCXX_GUARD_PENDING_BIT __guard_test_bit (1, 1)
      47  #define _GLIBCXX_GUARD_WAITING_BIT __guard_test_bit (2, 1)
      48    typedef int __guard;
      49  
      50  #define _GLIBCXX_GUARD_TEST_AND_ACQUIRE(x) \
      51    ((__atomic_load_n(x, __ATOMIC_ACQUIRE) & 1) != 0)
      52  #define _GLIBCXX_GUARD_SET_AND_RELEASE(x) \
      53    __atomic_store_n(x, 1, __ATOMIC_RELEASE)
      54  
      55    // We also want the element size in array cookies.
      56  #define _GLIBCXX_ELTSIZE_IN_COOKIE 1
      57  
      58    // __cxa_vec_ctor should return a pointer to the array.
      59    typedef void * __cxa_vec_ctor_return_type;
      60  #define _GLIBCXX_CXA_VEC_CTOR_RETURN(x) return x
      61    // Constructors and destructors return the "this" pointer.
      62    typedef void * __cxa_cdtor_return_type;
      63  
      64  #else // __ARM_EABI__
      65  
      66    // The generic ABI uses the first byte of a 64-bit guard variable.
      67  #define _GLIBCXX_GUARD_TEST(x) (*(char *) (x) != 0)
      68  #define _GLIBCXX_GUARD_SET(x) *(char *) (x) = 1
      69  #define _GLIBCXX_GUARD_BIT __guard_test_bit (0, 1)
      70  #define _GLIBCXX_GUARD_PENDING_BIT __guard_test_bit (1, 1)
      71  #define _GLIBCXX_GUARD_WAITING_BIT __guard_test_bit (2, 1)
      72    __extension__ typedef int __guard __attribute__((mode (__DI__)));
      73  
      74    // __cxa_vec_ctor has void return type.
      75    typedef void __cxa_vec_ctor_return_type;
      76  #define _GLIBCXX_CXA_VEC_CTOR_RETURN(x) return
      77    // Constructors and destructors do not return a value.
      78    typedef void __cxa_cdtor_return_type;
      79  
      80  #endif //!__ARM_EABI__
      81  
      82  #ifdef __cplusplus
      83    }
      84  } // namespace __cxxabiv1
      85  #endif
      86  
      87  #endif