1 // -*- C++ -*- Allocate exception objects.
2 // Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006
3 // Free Software Foundation, Inc.
5 // This file is part of GCC.
7 // GCC is free software; you can redistribute it and/or modify
8 // it under the terms of the GNU General Public License as published by
9 // the Free Software Foundation; either version 2, or (at your option)
12 // GCC is distributed in the hope that it will be useful,
13 // but WITHOUT ANY WARRANTY; without even the implied warranty of
14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 // GNU General Public License for more details.
17 // You should have received a copy of the GNU General Public License
18 // along with GCC; see the file COPYING. If not, write to
19 // the Free Software Foundation, 51 Franklin Street, Fifth Floor,
20 // Boston, MA 02110-1301, USA.
22 // As a special exception, you may use this file as part of a free software
23 // library without restriction. Specifically, if other files instantiate
24 // templates or use macros or inline functions from this file, or you compile
25 // this file and link it with other files to produce an executable, this
26 // file does not by itself cause the resulting executable to be covered by
27 // the GNU General Public License. This exception does not however
28 // invalidate any other reasons why the executable file might be covered by
29 // the GNU General Public License.
31 // This is derived from the C++ ABI for IA-64. Where we diverge
32 // for cross-architecture compatibility are noted with "@@@".
34 #include <bits/c++config.h>
41 #include "unwind-cxx.h"
42 #include <ext/concurrence.h>
49 // In a freestanding environment, these functions may not be available
50 // -- but for now, we assume that they are.
51 extern "C" void *malloc (std::size_t);
52 extern "C" void free(void *);
53 extern "C" void *memset (void *, int, std::size_t);
56 using namespace __cxxabiv1
;
58 // ??? How to control these parameters.
60 // Guess from the size of basic types how large a buffer is reasonable.
61 // Note that the basic c++ exception header has 13 pointers and 2 ints,
62 // so on a system with PSImode pointers we're talking about 56 bytes
66 # define EMERGENCY_OBJ_SIZE 128
67 # define EMERGENCY_OBJ_COUNT 16
68 #elif LONG_MAX == 2147483647
69 # define EMERGENCY_OBJ_SIZE 512
70 # define EMERGENCY_OBJ_COUNT 32
72 # define EMERGENCY_OBJ_SIZE 1024
73 # define EMERGENCY_OBJ_COUNT 64
77 # undef EMERGENCY_OBJ_COUNT
78 # define EMERGENCY_OBJ_COUNT 4
81 #if INT_MAX == 32767 || EMERGENCY_OBJ_COUNT <= 32
82 typedef unsigned int bitmask_type
;
84 typedef unsigned long bitmask_type
;
88 typedef char one_buffer
[EMERGENCY_OBJ_SIZE
] __attribute__((aligned
));
89 static one_buffer emergency_buffer
[EMERGENCY_OBJ_COUNT
];
90 static bitmask_type emergency_used
;
94 // A single mutex controlling emergency allocations.
95 __gnu_cxx::__mutex emergency_mutex
;
99 __cxxabiv1::__cxa_allocate_exception(std::size_t thrown_size
) throw()
103 thrown_size
+= sizeof (__cxa_exception
);
104 ret
= malloc (thrown_size
);
108 __gnu_cxx::__scoped_lock
sentry(emergency_mutex
);
110 bitmask_type used
= emergency_used
;
111 unsigned int which
= 0;
113 if (thrown_size
> EMERGENCY_OBJ_SIZE
)
118 if (++which
>= EMERGENCY_OBJ_COUNT
)
122 emergency_used
|= (bitmask_type
)1 << which
;
123 ret
= &emergency_buffer
[which
][0];
131 // We have an uncaught exception as soon as we allocate memory. This
132 // yields uncaught_exception() true during the copy-constructor that
133 // initializes the exception object. See Issue 475.
134 __cxa_eh_globals
*globals
= __cxa_get_globals ();
135 globals
->uncaughtExceptions
+= 1;
137 memset (ret
, 0, sizeof (__cxa_exception
));
139 return (void *)((char *)ret
+ sizeof (__cxa_exception
));
144 __cxxabiv1::__cxa_free_exception(void *vptr
) throw()
146 char *base
= (char *) emergency_buffer
;
147 char *ptr
= (char *) vptr
;
149 && ptr
< base
+ sizeof (emergency_buffer
))
151 const unsigned int which
152 = (unsigned) (ptr
- base
) / EMERGENCY_OBJ_SIZE
;
154 __gnu_cxx::__scoped_lock
sentry(emergency_mutex
);
155 emergency_used
&= ~((bitmask_type
)1 << which
);
158 free (ptr
- sizeof (__cxa_exception
));