cxa_exception_storage.cpp revision 928afcd281e2bcad26baaa67dfd035e547870a8d 
1//===--------------------- cxa_exception_storage.cpp ----------------------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is dual licensed under the MIT and the University of Illinois Open
6// Source Licenses. See LICENSE.TXT for details.
7//
8//
9//  This file implements the storage for the "Caught Exception Stack"
10//  http://www.codesourcery.com/public/cxx-abi/abi-eh.html (section 2.2.2)
11//
12//===----------------------------------------------------------------------===//
13
14#include "cxa_exception.hpp"
15
16#ifdef HAS_THREAD_LOCAL
17
18namespace __cxxabiv1 {
19
20namespace {
21    __cxa_eh_globals * __globals () throw () {
22        static thread_local __cxa_eh_globals eh_globals;
23        return &eh_globals;
24        }
25    }
26
27extern "C" {
28    __cxa_eh_globals * __cxa_get_globals      () throw() { return __globals (); }
29    __cxa_eh_globals * __cxa_get_globals_fast () throw() { return __globals (); }
30    }
31}
32
33#else
34
35#include <pthread.h>
36#include <cstdlib>          // for calloc, free
37#include "abort_message.h"
38
39//  In general, we treat all pthread errors as fatal.
40//  We cannot call std::terminate() because that will in turn
41//  call __cxa_get_globals() and cause infinite recursion.
42
43namespace __cxxabiv1 {
44namespace {
45    pthread_key_t  key_;
46
47    void destruct_ (void *p) throw () {
48        std::free ( p );
49        if ( 0 != ::pthread_setspecific ( key_, NULL ) )
50            abort_message("cannot zero out thread value for __cxa_get_globals()");
51        }
52
53    int construct_ () throw () {
54        if ( 0 != pthread_key_create ( &key_, destruct_ ) )
55            abort_message("cannot create pthread key for __cxa_get_globals()");
56        return 0;
57        }
58}
59
60extern "C" {
61    __cxa_eh_globals * __cxa_get_globals () throw () {
62
63    //  Try to get the globals for this thread
64        __cxa_eh_globals* retVal = __cxa_get_globals_fast ();
65
66    //  If this is the first time we've been asked for these globals, create them
67        if ( NULL == retVal ) {
68            retVal = static_cast<__cxa_eh_globals*>
69                        (std::calloc (1, sizeof (__cxa_eh_globals)));
70            if ( NULL == retVal )
71                abort_message("cannot allocate __cxa_eh_globals");
72            if ( 0 != pthread_setspecific ( key_, retVal ) )
73               abort_message("pthread_setspecific failure in __cxa_get_globals()");
74           }
75        return retVal;
76        }
77
78    __cxa_eh_globals * __cxa_get_globals_fast () throw () {
79    //  First time through, create the key.
80        static int init = construct_();
81        return static_cast<__cxa_eh_globals*>(::pthread_getspecific(key_));
82        }
83
84}
85}
86#endif
87