// -*- C++ -*- Allocate exception objects.
// Copyright (C) 2001-2013 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 3, 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.
//
// 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
// <http://www.gnu.org/licenses/>.
// This is derived from the C++ ABI for IA-64. Where we diverge
// for cross-architecture compatibility are noted with "@@@".
#include <bits/c++config.h>
#include <cstdlib>
#if _GLIBCXX_HOSTED
#include <cstring>
#endif
#include <climits>
#include <exception>
#include "unwind-cxx.h"
#include <ext/concurrence.h>
#if _GLIBCXX_HOSTED
using std::free;
using std::malloc;
using std::memset;
#else
// In a freestanding environment, these functions may not be available
// -- but for now, we assume that they are.
extern "C" void *malloc (std::size_t);
extern "C" void free(void *);
extern "C" void *memset (void *, int, std::size_t);
#endif
using namespace __cxxabiv1;
// ??? How to control these parameters.
// Guess from the size of basic types how large a buffer is reasonable.
// Note that the basic c++ exception header has 13 pointers and 2 ints,
// so on a system with PSImode pointers we're talking about 56 bytes
// just for overhead.
#if INT_MAX == 32767
# define EMERGENCY_OBJ_SIZE 128
# define EMERGENCY_OBJ_COUNT 16
#elif !defined (_GLIBCXX_LLP64) && LONG_MAX == 2147483647
# define EMERGENCY_OBJ_SIZE 512
# define EMERGENCY_OBJ_COUNT 32
#else
# define EMERGENCY_OBJ_SIZE 1024
# define EMERGENCY_OBJ_COUNT 64
#endif
#ifndef __GTHREADS
# undef EMERGENCY_OBJ_COUNT
# define EMERGENCY_OBJ_COUNT 4
#endif
#if INT_MAX == 32767 || EMERGENCY_OBJ_COUNT <= 32
typedef unsigned int bitmask_type;
#else
#if defined (_GLIBCXX_LLP64)
typedef unsigned long long bitmask_type;
#else
typedef unsigned long bitmask_type;
#endif
#endif
typedef char one_buffer[EMERGENCY_OBJ_SIZE] __attribute__((aligned));
static one_buffer emergency_buffer[EMERGENCY_OBJ_COUNT];
static bitmask_type emergency_used;
static __cxa_dependent_exception dependents_buffer[EMERGENCY_OBJ_COUNT];
static bitmask_type dependents_used;
namespace
{
// A single mutex controlling emergency allocations.
__gnu_cxx::__mutex emergency_mutex;
}
extern "C" void *
__cxxabiv1::__cxa_allocate_exception(std::size_t thrown_size) _GLIBCXX_NOTHROW
{
void *ret;
thrown_size += sizeof (__cxa_refcounted_exception);
ret = malloc (thrown_size);
if (! ret)
{
__gnu_cxx::__scoped_lock sentry(emergency_mutex);
bitmask_type used = emergency_used;
unsigned int which = 0;
if (thrown_size > EMERGENCY_OBJ_SIZE)
goto failed;
while (used & 1)
{
used >>= 1;
if (++which >= EMERGENCY_OBJ_COUNT)
goto failed;
}
emergency_used |= (bitmask_type)1 << which;
ret = &emergency_buffer[which][0];
failed:;
if (!ret)
std::terminate ();
}
memset (ret, 0, sizeof (__cxa_refcounted_exception));
return (void *)((char *)ret + sizeof (__cxa_refcounted_exception));
}
extern "C" void
__cxxabiv1::__cxa_free_exception(void *vptr) _GLIBCXX_NOTHROW
{
char *base = (char *) emergency_buffer;
char *ptr = (char *) vptr;
if (ptr >= base
&& ptr < base + sizeof (emergency_buffer))
{
const unsigned int which
= (unsigned) (ptr - base) / EMERGENCY_OBJ_SIZE;
__gnu_cxx::__scoped_lock sentry(emergency_mutex);
emergency_used &= ~((bitmask_type)1 << which);
}
else
free (ptr - sizeof (__cxa_refcounted_exception));
}
extern "C" __cxa_dependent_exception*
__cxxabiv1::__cxa_allocate_dependent_exception() _GLIBCXX_NOTHROW
{
__cxa_dependent_exception *ret;
ret = static_cast<__cxa_dependent_exception*>
(malloc (sizeof (__cxa_dependent_exception)));
if (!ret)
{
__gnu_cxx::__scoped_lock sentry(emergency_mutex);
bitmask_type used = dependents_used;
unsigned int which = 0;
while (used & 1)
{
used >>= 1;
if (++which >= EMERGENCY_OBJ_COUNT)
goto failed;
}
dependents_used |= (bitmask_type)1 << which;
ret = &dependents_buffer[which];
failed:;
if (!ret)
std::terminate ();
}
memset (ret, 0, sizeof (__cxa_dependent_exception));
return ret;
}
extern "C" void
__cxxabiv1::__cxa_free_dependent_exception
(__cxa_dependent_exception *vptr) _GLIBCXX_NOTHROW
{
char *base = (char *) dependents_buffer;
char *ptr = (char *) vptr;
if (ptr >= base
&& ptr < base + sizeof (dependents_buffer))
{
const unsigned int which
= (unsigned) (ptr - base) / sizeof (__cxa_dependent_exception);
__gnu_cxx::__scoped_lock sentry(emergency_mutex);
dependents_used &= ~((bitmask_type)1 << which);
}
else
free (vptr);
}