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b2e863b8 | 1 | /* SJLJ exception handling and frame unwind runtime interface routines. |
7adcbafe | 2 | Copyright (C) 1997-2022 Free Software Foundation, Inc. |
52a11cbf | 3 | |
1322177d | 4 | This file is part of GCC. |
52a11cbf | 5 | |
1322177d LB |
6 | GCC is free software; you can redistribute it and/or modify it |
7 | under the terms of the GNU General Public License as published by | |
748086b7 | 8 | the Free Software Foundation; either version 3, or (at your option) |
52a11cbf RH |
9 | any later version. |
10 | ||
1322177d LB |
11 | GCC is distributed in the hope that it will be useful, but WITHOUT |
12 | ANY WARRANTY; without even the implied warranty of MERCHANTABILITY | |
13 | or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public | |
14 | License for more details. | |
52a11cbf | 15 | |
748086b7 JJ |
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/>. */ | |
52a11cbf RH |
24 | |
25 | #include "tconfig.h" | |
26 | #include "tsystem.h" | |
4977bab6 ZW |
27 | #include "coretypes.h" |
28 | #include "tm.h" | |
852b75ed | 29 | #include "libgcc_tm.h" |
52a11cbf RH |
30 | #include "unwind.h" |
31 | #include "gthr.h" | |
32 | ||
0d24f4d1 | 33 | #ifdef __USING_SJLJ_EXCEPTIONS__ |
52a11cbf | 34 | |
53d68b9f | 35 | #ifdef __LIBGCC_DONT_USE_BUILTIN_SETJMP__ |
9defc9b7 | 36 | #ifndef inhibit_libc |
52a11cbf RH |
37 | #include <setjmp.h> |
38 | #else | |
53d68b9f | 39 | typedef void *jmp_buf[__LIBGCC_JMP_BUF_SIZE__]; |
9defc9b7 RH |
40 | extern void longjmp(jmp_buf, int) __attribute__((noreturn)); |
41 | #endif | |
42 | #else | |
52a11cbf RH |
43 | #define longjmp __builtin_longjmp |
44 | #endif | |
45 | ||
4f6c2131 EB |
46 | /* The setjmp side is dealt with in the except.c file. */ |
47 | #undef setjmp | |
48 | #define setjmp setjmp_should_not_be_used_in_this_file | |
49 | ||
50 | ||
52a11cbf RH |
51 | /* This structure is allocated on the stack of the target function. |
52 | This must match the definition created in except.c:init_eh. */ | |
53 | struct SjLj_Function_Context | |
54 | { | |
55 | /* This is the chain through all registered contexts. It is | |
56 | filled in by _Unwind_SjLj_Register. */ | |
57 | struct SjLj_Function_Context *prev; | |
58 | ||
59 | /* This is assigned in by the target function before every call | |
60 | to the index of the call site in the lsda. It is assigned by | |
61 | the personality routine to the landing pad index. */ | |
62 | int call_site; | |
63 | ||
64 | /* This is how data is returned from the personality routine to | |
65 | the target function's handler. */ | |
66 | _Unwind_Word data[4]; | |
67 | ||
68 | /* These are filled in once by the target function before any | |
69 | exceptions are expected to be handled. */ | |
70 | _Unwind_Personality_Fn personality; | |
71 | void *lsda; | |
72 | ||
53d68b9f | 73 | #ifdef __LIBGCC_DONT_USE_BUILTIN_SETJMP__ |
52a11cbf RH |
74 | /* We don't know what sort of alignment requirements the system |
75 | jmp_buf has. We over estimated in except.c, and now we have | |
41077ce4 | 76 | to match that here just in case the system *didn't* have more |
52a11cbf RH |
77 | restrictive requirements. */ |
78 | jmp_buf jbuf __attribute__((aligned)); | |
79 | #else | |
80 | void *jbuf[]; | |
81 | #endif | |
82 | }; | |
83 | ||
84 | struct _Unwind_Context | |
85 | { | |
86 | struct SjLj_Function_Context *fc; | |
87 | }; | |
88 | ||
41077ce4 | 89 | typedef struct |
52a11cbf RH |
90 | { |
91 | _Unwind_Personality_Fn personality; | |
92 | } _Unwind_FrameState; | |
93 | ||
94 | \f | |
95 | /* Manage the chain of registered function contexts. */ | |
96 | ||
97 | /* Single threaded fallback chain. */ | |
98 | static struct SjLj_Function_Context *fc_static; | |
99 | ||
100 | #if __GTHREADS | |
101 | static __gthread_key_t fc_key; | |
102 | static int use_fc_key = -1; | |
103 | ||
52a11cbf RH |
104 | static void |
105 | fc_key_init (void) | |
106 | { | |
4977bab6 | 107 | use_fc_key = __gthread_key_create (&fc_key, 0) == 0; |
52a11cbf RH |
108 | } |
109 | ||
110 | static void | |
111 | fc_key_init_once (void) | |
112 | { | |
113 | static __gthread_once_t once = __GTHREAD_ONCE_INIT; | |
114 | if (__gthread_once (&once, fc_key_init) != 0 || use_fc_key < 0) | |
115 | use_fc_key = 0; | |
116 | } | |
117 | #endif | |
118 | ||
119 | void | |
120 | _Unwind_SjLj_Register (struct SjLj_Function_Context *fc) | |
121 | { | |
122 | #if __GTHREADS | |
123 | if (use_fc_key < 0) | |
124 | fc_key_init_once (); | |
125 | ||
126 | if (use_fc_key) | |
127 | { | |
128 | fc->prev = __gthread_getspecific (fc_key); | |
129 | __gthread_setspecific (fc_key, fc); | |
130 | } | |
131 | else | |
132 | #endif | |
133 | { | |
134 | fc->prev = fc_static; | |
135 | fc_static = fc; | |
136 | } | |
137 | } | |
138 | ||
139 | static inline struct SjLj_Function_Context * | |
140 | _Unwind_SjLj_GetContext (void) | |
141 | { | |
142 | #if __GTHREADS | |
143 | if (use_fc_key < 0) | |
144 | fc_key_init_once (); | |
145 | ||
146 | if (use_fc_key) | |
147 | return __gthread_getspecific (fc_key); | |
148 | #endif | |
149 | return fc_static; | |
150 | } | |
151 | ||
152 | static inline void | |
153 | _Unwind_SjLj_SetContext (struct SjLj_Function_Context *fc) | |
154 | { | |
155 | #if __GTHREADS | |
156 | if (use_fc_key < 0) | |
157 | fc_key_init_once (); | |
158 | ||
159 | if (use_fc_key) | |
160 | __gthread_setspecific (fc_key, fc); | |
161 | else | |
162 | #endif | |
163 | fc_static = fc; | |
164 | } | |
165 | ||
166 | void | |
167 | _Unwind_SjLj_Unregister (struct SjLj_Function_Context *fc) | |
168 | { | |
169 | _Unwind_SjLj_SetContext (fc->prev); | |
170 | } | |
171 | ||
172 | \f | |
173 | /* Get/set the return data value at INDEX in CONTEXT. */ | |
174 | ||
175 | _Unwind_Word | |
176 | _Unwind_GetGR (struct _Unwind_Context *context, int index) | |
177 | { | |
178 | return context->fc->data[index]; | |
179 | } | |
180 | ||
378683cf RH |
181 | /* Get the value of the CFA as saved in CONTEXT. */ |
182 | ||
183 | _Unwind_Word | |
525996eb | 184 | _Unwind_GetCFA (struct _Unwind_Context *context __attribute__((unused))) |
378683cf RH |
185 | { |
186 | /* ??? Ideally __builtin_setjmp places the CFA in the jmpbuf. */ | |
0e32bbcc | 187 | |
53d68b9f | 188 | #ifndef __LIBGCC_DONT_USE_BUILTIN_SETJMP__ |
0e32bbcc DJ |
189 | /* This is a crude imitation of the CFA: the saved stack pointer. |
190 | This is roughly the CFA of the frame before CONTEXT. When using the | |
191 | DWARF-2 unwinder _Unwind_GetCFA returns the CFA of the frame described | |
192 | by CONTEXT instead; but for DWARF-2 the cleanups associated with | |
193 | CONTEXT have already been run, and for SJLJ they have not yet been. */ | |
194 | if (context->fc != NULL) | |
195 | return (_Unwind_Word) context->fc->jbuf[2]; | |
196 | #endif | |
197 | ||
198 | /* Otherwise we're out of luck for now. */ | |
d234bf61 | 199 | return (_Unwind_Word) 0; |
378683cf RH |
200 | } |
201 | ||
52a11cbf RH |
202 | void |
203 | _Unwind_SetGR (struct _Unwind_Context *context, int index, _Unwind_Word val) | |
204 | { | |
205 | context->fc->data[index] = val; | |
206 | } | |
207 | ||
208 | /* Get the call-site index as saved in CONTEXT. */ | |
209 | ||
210 | _Unwind_Ptr | |
211 | _Unwind_GetIP (struct _Unwind_Context *context) | |
212 | { | |
213 | return context->fc->call_site + 1; | |
214 | } | |
215 | ||
754e45a8 JJ |
216 | _Unwind_Ptr |
217 | _Unwind_GetIPInfo (struct _Unwind_Context *context, int *ip_before_insn) | |
218 | { | |
219 | *ip_before_insn = 0; | |
759580ed AH |
220 | if (context->fc != NULL) |
221 | return context->fc->call_site + 1; | |
222 | else | |
223 | return 0; | |
754e45a8 JJ |
224 | } |
225 | ||
52a11cbf RH |
226 | /* Set the return landing pad index in CONTEXT. */ |
227 | ||
228 | void | |
229 | _Unwind_SetIP (struct _Unwind_Context *context, _Unwind_Ptr val) | |
230 | { | |
231 | context->fc->call_site = val - 1; | |
232 | } | |
233 | ||
234 | void * | |
235 | _Unwind_GetLanguageSpecificData (struct _Unwind_Context *context) | |
236 | { | |
237 | return context->fc->lsda; | |
238 | } | |
239 | ||
240 | _Unwind_Ptr | |
2adaabc6 | 241 | _Unwind_GetRegionStart (struct _Unwind_Context *context __attribute__((unused)) ) |
52a11cbf RH |
242 | { |
243 | return 0; | |
244 | } | |
245 | ||
5dafd282 | 246 | void * |
525996eb | 247 | _Unwind_FindEnclosingFunction (void *pc __attribute__((unused))) |
5dafd282 AH |
248 | { |
249 | return NULL; | |
250 | } | |
251 | ||
48941cb8 RH |
252 | #ifndef __ia64__ |
253 | _Unwind_Ptr | |
2adaabc6 | 254 | _Unwind_GetDataRelBase (struct _Unwind_Context *context __attribute__((unused)) ) |
48941cb8 RH |
255 | { |
256 | return 0; | |
257 | } | |
258 | ||
259 | _Unwind_Ptr | |
2adaabc6 | 260 | _Unwind_GetTextRelBase (struct _Unwind_Context *context __attribute__((unused)) ) |
48941cb8 RH |
261 | { |
262 | return 0; | |
263 | } | |
264 | #endif | |
52a11cbf RH |
265 | \f |
266 | static inline _Unwind_Reason_Code | |
267 | uw_frame_state_for (struct _Unwind_Context *context, _Unwind_FrameState *fs) | |
268 | { | |
269 | if (context->fc == NULL) | |
270 | { | |
271 | fs->personality = NULL; | |
272 | return _URC_END_OF_STACK; | |
273 | } | |
274 | else | |
275 | { | |
276 | fs->personality = context->fc->personality; | |
277 | return _URC_NO_REASON; | |
278 | } | |
279 | } | |
280 | ||
281 | static inline void | |
282 | uw_update_context (struct _Unwind_Context *context, | |
283 | _Unwind_FrameState *fs __attribute__((unused)) ) | |
284 | { | |
285 | context->fc = context->fc->prev; | |
286 | } | |
287 | ||
60aef23e DJ |
288 | static void |
289 | uw_advance_context (struct _Unwind_Context *context, _Unwind_FrameState *fs) | |
290 | { | |
291 | _Unwind_SjLj_Unregister (context->fc); | |
292 | uw_update_context (context, fs); | |
293 | } | |
294 | ||
41077ce4 | 295 | static inline void |
52a11cbf RH |
296 | uw_init_context (struct _Unwind_Context *context) |
297 | { | |
298 | context->fc = _Unwind_SjLj_GetContext (); | |
299 | } | |
300 | ||
6de9cd9a DN |
301 | static void __attribute__((noreturn)) |
302 | uw_install_context (struct _Unwind_Context *current __attribute__((unused)), | |
1ebafce0 IT |
303 | struct _Unwind_Context *target, |
304 | unsigned long frames __attribute__((unused))) | |
6de9cd9a DN |
305 | { |
306 | _Unwind_SjLj_SetContext (target->fc); | |
307 | longjmp (target->fc->jbuf, 1); | |
308 | } | |
52a11cbf RH |
309 | |
310 | static inline _Unwind_Ptr | |
311 | uw_identify_context (struct _Unwind_Context *context) | |
312 | { | |
313 | return (_Unwind_Ptr) context->fc; | |
314 | } | |
315 | ||
316 | ||
317 | /* Play games with unwind symbols so that we can have call frame | |
318 | and sjlj symbols in the same shared library. Not that you can | |
319 | use them simultaneously... */ | |
320 | #define _Unwind_RaiseException _Unwind_SjLj_RaiseException | |
321 | #define _Unwind_ForcedUnwind _Unwind_SjLj_ForcedUnwind | |
322 | #define _Unwind_Resume _Unwind_SjLj_Resume | |
a944ceb9 | 323 | #define _Unwind_Resume_or_Rethrow _Unwind_SjLj_Resume_or_Rethrow |
52a11cbf RH |
324 | |
325 | #include "unwind.inc" | |
326 | ||
327 | #endif /* USING_SJLJ_EXCEPTIONS */ |