1// -*- C++ -*- Manage the thread-local exception globals.
2// Copyright (C) 2001-2017 Free Software Foundation, Inc.
3//
4// This file is part of GCC.
5//
6// GCC is free software; you can redistribute it and/or modify
7// it under the terms of the GNU General Public License as published by
8// the Free Software Foundation; either version 3, or (at your option)
9// any later version.
10//
11// GCC 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#include <bits/c++config.h>
26#include <exception>
27#include <cstdlib>
28#include "cxxabi.h"
29#include "unwind-cxx.h"
30#include "bits/gthr.h"
31
32#if _GLIBCXX_HOSTED
33using std::free;
34using std::malloc;
35#else
36// In a freestanding environment, these functions may not be
37// available -- but for now, we assume that they are.
38extern "C" void *malloc (std::size_t);
39extern "C" void free(void *);
40#endif
41
42using namespace __cxxabiv1;
43
44#if _GLIBCXX_HAVE_TLS
45
46namespace
47{
48 abi::__cxa_eh_globals*
49 get_global() _GLIBCXX_NOTHROW
50 {
51 static __thread abi::__cxa_eh_globals global;
52 return &global;
53 }
54} // anonymous namespace
55
56extern "C" __cxa_eh_globals*
57__cxxabiv1::__cxa_get_globals_fast() _GLIBCXX_NOTHROW
58{ return get_global(); }
59
60extern "C" __cxa_eh_globals*
61__cxxabiv1::__cxa_get_globals() _GLIBCXX_NOTHROW
62{ return get_global(); }
63
64
65#else
66
67// Single-threaded fallback buffer.
68static __cxa_eh_globals eh_globals;
69
70#if __GTHREADS
71
72static void
73eh_globals_dtor(void* ptr)
74{
75 if (ptr)
76 {
77 __cxa_eh_globals* g = reinterpret_cast<__cxa_eh_globals*>(ptr);
78 __cxa_exception* exn = g->caughtExceptions;
79 __cxa_exception* next;
80 while (exn)
81 {
82 next = exn->nextException;
83 _Unwind_DeleteException(&exn->unwindHeader);
84 exn = next;
85 }
86 free(ptr);
87 }
88}
89
90struct __eh_globals_init
91{
92 __gthread_key_t _M_key;
93 bool _M_init;
94
95 __eh_globals_init() : _M_init(false)
96 {
97 if (__gthread_active_p())
98 _M_init = __gthread_key_create(&_M_key, eh_globals_dtor) == 0;
99 }
100
101 ~__eh_globals_init()
102 {
103 if (_M_init)
104 __gthread_key_delete(_M_key);
105 _M_init = false;
106 }
107};
108
109static __eh_globals_init init;
110
111extern "C" __cxa_eh_globals*
112__cxxabiv1::__cxa_get_globals_fast() _GLIBCXX_NOTHROW
113{
114 __cxa_eh_globals* g;
115 if (init._M_init)
116 g = static_cast<__cxa_eh_globals*>(__gthread_getspecific(init._M_key));
117 else
118 g = &eh_globals;
119 return g;
120}
121
122extern "C" __cxa_eh_globals*
123__cxxabiv1::__cxa_get_globals() _GLIBCXX_NOTHROW
124{
125 __cxa_eh_globals* g;
126 if (init._M_init)
127 {
128 g = static_cast<__cxa_eh_globals*>(__gthread_getspecific(init._M_key));
129 if (!g)
130 {
131 void* v = malloc(sizeof(__cxa_eh_globals));
132 if (v == 0 || __gthread_setspecific(init._M_key, v) != 0)
133 std::terminate();
134 g = static_cast<__cxa_eh_globals*>(v);
135 g->caughtExceptions = 0;
136 g->uncaughtExceptions = 0;
137#ifdef __ARM_EABI_UNWINDER__
138 g->propagatingExceptions = 0;
139#endif
140 }
141 }
142 else
143 g = &eh_globals;
144 return g;
145}
146
147#else
148
149extern "C" __cxa_eh_globals*
150__cxxabiv1::__cxa_get_globals_fast() _GLIBCXX_NOTHROW
151{ return &eh_globals; }
152
153extern "C" __cxa_eh_globals*
154__cxxabiv1::__cxa_get_globals() _GLIBCXX_NOTHROW
155{ return &eh_globals; }
156
157#endif
158
159#endif
160