dyld-635.2.tar.gz
[apple/dyld.git] / src / dyldExceptions.c
1 /* -*- mode: C++; c-basic-offset: 4; tab-width: 4 -*-
2 *
3 * Copyright (c) 2004-2011 Apple Inc. All rights reserved.
4 *
5 * @APPLE_LICENSE_HEADER_START@
6 *
7 * This file contains Original Code and/or Modifications of Original Code
8 * as defined in and that are subject to the Apple Public Source License
9 * Version 2.0 (the 'License'). You may not use this file except in
10 * compliance with the License. Please obtain a copy of the License at
11 * http://www.opensource.apple.com/apsl/ and read it before using this
12 * file.
13 *
14 * The Original Code and all software distributed under the License are
15 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
16 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
17 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
19 * Please see the License for the specific language governing rights and
20 * limitations under the License.
21 *
22 * @APPLE_LICENSE_HEADER_END@
23 */
24
25 #include <stdlib.h>
26 #include <string.h>
27 #include <mach-o/loader.h>
28 #include <unistd.h>
29 #include <stdio.h>
30 #include <stdbool.h>
31 #include <stdarg.h>
32 #include <pthread.h>
33 #include <Availability.h>
34
35 #include "mach-o/dyld_priv.h"
36 #include "dyldLibSystemInterface.h"
37
38
39 extern void _ZN4dyld3logEPKcz(const char*, ...);
40 extern struct LibSystemHelpers* _ZN4dyld17gLibSystemHelpersE;
41
42
43 #if __LP64__
44 #define LC_SEGMENT_COMMAND LC_SEGMENT_64
45 #define macho_header mach_header_64
46 #define macho_segment_command segment_command_64
47 #define macho_section section_64
48 #define getsectdatafromheader getsectdatafromheader_64
49 #else
50 #define LC_SEGMENT_COMMAND LC_SEGMENT
51 #define macho_header mach_header
52 #define macho_segment_command segment_command
53 #define macho_section section
54 #endif
55
56
57 //
58 // The standard versions of __cxa_get_globals*() from libstdc++-static.a cannot be used.
59 // On Mac OS X, they use keymgr which dyld does not implement.
60 // On iPhoneOS, they use pthread_key_create which dyld cannot use.
61 //
62 // Implement these ourselves to make upcalls into libSystem to malloc and create a pthread key
63 //
64 static pthread_key_t sCxaKey = 0;
65 static char sPreMainCxaGlobals[2*sizeof(long)];
66
67 // called by libstdc++.a
68 char* __cxa_get_globals()
69 {
70 // if libSystem.dylib not yet initialized, or is old libSystem, use shared global
71 if ( (_ZN4dyld17gLibSystemHelpersE == NULL) || (_ZN4dyld17gLibSystemHelpersE->version < 7) )
72 return sPreMainCxaGlobals;
73
74 if ( sCxaKey == 0 ) {
75 // create key
76 // we don't need a lock because only one thread can be in dyld at a time
77 _ZN4dyld17gLibSystemHelpersE->pthread_key_create(&sCxaKey, &free);
78 }
79 char* data = (char*)_ZN4dyld17gLibSystemHelpersE->pthread_getspecific(sCxaKey);
80 if ( data == NULL ) {
81 long* t = (long*)calloc(2,sizeof(long));
82 data = (char*)t;
83 _ZN4dyld17gLibSystemHelpersE->pthread_setspecific(sCxaKey, data);
84 }
85 return data;
86 }
87
88 // called by libstdc++.a
89 char* __cxa_get_globals_fast()
90 {
91 // if libSystem.dylib not yet initialized, or is old libSystem, use shared global
92 if ( (_ZN4dyld17gLibSystemHelpersE == NULL) || (_ZN4dyld17gLibSystemHelpersE->version < 7) )
93 return sPreMainCxaGlobals;
94
95 return _ZN4dyld17gLibSystemHelpersE->pthread_getspecific(sCxaKey);
96 }
97
98
99
100 #if !__USING_SJLJ_EXCEPTIONS__
101 //
102 // When dyld uses zero-cost exceptions it just needs to implement
103 // _dyld_find_unwind_sections to return sections inside dyld proper.
104 //
105
106 extern void* ehStart __asm("section$start$__TEXT$__eh_frame");
107 extern void* ehEnd __asm("section$end$__TEXT$__eh_frame");
108 extern void* uwStart __asm("section$start$__TEXT$__unwind_info");
109 extern void* uwEnd __asm("section$end$__TEXT$__unwind_info");
110
111 extern void* textStart __asm("section$start$__TEXT$__text");
112 extern void* textEnd __asm("section$end$__TEXT$__text");
113
114 extern void* __dso_handle;
115
116 // called by libuwind code to find unwind information sections in dyld
117 bool _dyld_find_unwind_sections(void* addr, struct dyld_unwind_sections* info)
118 {
119 if ( ((void*)&textStart < addr) && (addr < (void*)&textEnd) ) {
120 info->mh = (struct mach_header*)&__dso_handle;
121 info->dwarf_section = &ehStart;
122 info->dwarf_section_length = ((char*)&ehEnd - (char*)&ehStart);
123 info->compact_unwind_section = &uwStart;
124 info->compact_unwind_section_length = ((char*)&uwEnd - (char*)&uwStart);
125 return true;
126 }
127 else {
128 return false;
129 }
130 }
131
132 #else
133 //
134 // When dyld uses setjump-longjump exceptions it needs to implement
135 // routines to push and pop a stack of _Unwind_FunctionContext.
136 //
137
138 struct _Unwind_FunctionContext
139 {
140 // next function in stack of handlers
141 struct _Unwind_FunctionContext* prev;
142
143 };
144
145
146 static pthread_key_t sThreadChainKey = 0;
147 static struct _Unwind_FunctionContext* sStaticThreadChain = NULL;
148
149 //
150 // When libSystem's initializers are run, they call back into dyld's
151 // registerThreadHelpers which creates a pthread key and calls
152 // __Unwind_SjLj_SetThreadKey().
153 //
154 void __Unwind_SjLj_SetThreadKey(pthread_key_t key)
155 {
156 sThreadChainKey = key;
157 //_ZN4dyld3logEPKcz("__Unwind_SjLj_SetThreadKey(key=%d), sStaticThreadChain=%p\n", key, sStaticThreadChain);
158 // switch static chain to be per thread
159 _ZN4dyld17gLibSystemHelpersE->pthread_setspecific(sThreadChainKey, sStaticThreadChain);
160 sStaticThreadChain = NULL;
161 //_ZN4dyld3logEPKcz("__Unwind_SjLj_SetThreadKey(key=%d), result=%d, new top=%p\n", key, result, pthread_getspecific(sThreadChainKey));
162 }
163
164
165 //static void printChain()
166 //{
167 // _ZN4dyld3logEPKcz("chain: ");
168 // struct _Unwind_FunctionContext* start = sStaticThreadChain;
169 // if ( sThreadChainKey != 0 ) {
170 // start = (struct _Unwind_FunctionContext*)pthread_getspecific(sThreadChainKey);
171 // }
172 // for (struct _Unwind_FunctionContext* p = start; p != NULL; p = p->prev) {
173 // _ZN4dyld3logEPKcz("%p -> ", p);
174 // }
175 // _ZN4dyld3logEPKcz("\n");
176 //}
177
178
179 struct _Unwind_FunctionContext* __Unwind_SjLj_GetTopOfFunctionStack()
180 {
181 //_ZN4dyld3logEPKcz("__Unwind_SjLj_GetTopOfFunctionStack(), key=%d, ", sThreadChainKey);
182 //printChain();
183 if ( sThreadChainKey != 0 ) {
184 return (struct _Unwind_FunctionContext*)pthread_getspecific(sThreadChainKey);
185 }
186 else {
187 return sStaticThreadChain;
188 }
189 }
190
191 void __Unwind_SjLj_SetTopOfFunctionStack(struct _Unwind_FunctionContext* fc)
192 {
193 //_ZN4dyld3logEPKcz("__Unwind_SjLj_SetTopOfFunctionStack(%p), key=%d, prev=%p\n",
194 // fc, sThreadChainKey, (fc != NULL) ? fc->prev : NULL);
195 if ( sThreadChainKey != 0 )
196 _ZN4dyld17gLibSystemHelpersE->pthread_setspecific(sThreadChainKey, fc);
197 else
198 sStaticThreadChain = fc;
199 //_ZN4dyld3logEPKcz("__Unwind_SjLj_SetTopOfFunctionStack(%p), key=%d, ", fc, sThreadChainKey);
200 //printChain();
201 }
202
203 #endif
204
205
206