2005-05-19 Paul Brook <paul@codesourcery.com>
[official-gcc.git] / gcc / unwind-sjlj.c
blob0dd4a8395a39c80821028590dccb5e30bc69aa8e
1 /* SJLJ exception handling and frame unwind runtime interface routines.
2 Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004
3 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it
8 under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2, or (at your option)
10 any later version.
12 In addition to the permissions in the GNU General Public License, the
13 Free Software Foundation gives you unlimited permission to link the
14 compiled version of this file into combinations with other programs,
15 and to distribute those combinations without any restriction coming
16 from the use of this file. (The General Public License restrictions
17 do apply in other respects; for example, they cover modification of
18 the file, and distribution when not linked into a combined
19 executable.)
21 GCC is distributed in the hope that it will be useful, but WITHOUT
22 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
23 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
24 License for more details.
26 You should have received a copy of the GNU General Public License
27 along with GCC; see the file COPYING. If not, write to the Free
28 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
29 02111-1307, USA. */
31 #include "tconfig.h"
32 #include "tsystem.h"
33 #include "coretypes.h"
34 #include "tm.h"
35 #include "unwind.h"
36 #include "gthr.h"
38 #ifdef __USING_SJLJ_EXCEPTIONS__
40 #ifdef DONT_USE_BUILTIN_SETJMP
41 #ifndef inhibit_libc
42 #include <setjmp.h>
43 #else
44 typedef void *jmp_buf[JMP_BUF_SIZE];
45 extern void longjmp(jmp_buf, int) __attribute__((noreturn));
46 #endif
47 #else
48 #define setjmp __builtin_setjmp
49 #define longjmp __builtin_longjmp
50 #endif
52 /* This structure is allocated on the stack of the target function.
53 This must match the definition created in except.c:init_eh. */
54 struct SjLj_Function_Context
56 /* This is the chain through all registered contexts. It is
57 filled in by _Unwind_SjLj_Register. */
58 struct SjLj_Function_Context *prev;
60 /* This is assigned in by the target function before every call
61 to the index of the call site in the lsda. It is assigned by
62 the personality routine to the landing pad index. */
63 int call_site;
65 /* This is how data is returned from the personality routine to
66 the target function's handler. */
67 _Unwind_Word data[4];
69 /* These are filled in once by the target function before any
70 exceptions are expected to be handled. */
71 _Unwind_Personality_Fn personality;
72 void *lsda;
74 #ifdef DONT_USE_BUILTIN_SETJMP
75 /* We don't know what sort of alignment requirements the system
76 jmp_buf has. We over estimated in except.c, and now we have
77 to match that here just in case the system *didn't* have more
78 restrictive requirements. */
79 jmp_buf jbuf __attribute__((aligned));
80 #else
81 void *jbuf[];
82 #endif
85 struct _Unwind_Context
87 struct SjLj_Function_Context *fc;
90 typedef struct
92 _Unwind_Personality_Fn personality;
93 } _Unwind_FrameState;
96 /* Manage the chain of registered function contexts. */
98 /* Single threaded fallback chain. */
99 static struct SjLj_Function_Context *fc_static;
101 #if __GTHREADS
102 static __gthread_key_t fc_key;
103 static int use_fc_key = -1;
105 static void
106 fc_key_init (void)
108 use_fc_key = __gthread_key_create (&fc_key, 0) == 0;
111 static void
112 fc_key_init_once (void)
114 static __gthread_once_t once = __GTHREAD_ONCE_INIT;
115 if (__gthread_once (&once, fc_key_init) != 0 || use_fc_key < 0)
116 use_fc_key = 0;
118 #endif
120 void
121 _Unwind_SjLj_Register (struct SjLj_Function_Context *fc)
123 #if __GTHREADS
124 if (use_fc_key < 0)
125 fc_key_init_once ();
127 if (use_fc_key)
129 fc->prev = __gthread_getspecific (fc_key);
130 __gthread_setspecific (fc_key, fc);
132 else
133 #endif
135 fc->prev = fc_static;
136 fc_static = fc;
140 static inline struct SjLj_Function_Context *
141 _Unwind_SjLj_GetContext (void)
143 #if __GTHREADS
144 if (use_fc_key < 0)
145 fc_key_init_once ();
147 if (use_fc_key)
148 return __gthread_getspecific (fc_key);
149 #endif
150 return fc_static;
153 static inline void
154 _Unwind_SjLj_SetContext (struct SjLj_Function_Context *fc)
156 #if __GTHREADS
157 if (use_fc_key < 0)
158 fc_key_init_once ();
160 if (use_fc_key)
161 __gthread_setspecific (fc_key, fc);
162 else
163 #endif
164 fc_static = fc;
167 void
168 _Unwind_SjLj_Unregister (struct SjLj_Function_Context *fc)
170 _Unwind_SjLj_SetContext (fc->prev);
174 /* Get/set the return data value at INDEX in CONTEXT. */
176 _Unwind_Word
177 _Unwind_GetGR (struct _Unwind_Context *context, int index)
179 return context->fc->data[index];
182 /* Get the value of the CFA as saved in CONTEXT. */
184 _Unwind_Word
185 _Unwind_GetCFA (struct _Unwind_Context *context __attribute__((unused)))
187 /* ??? Ideally __builtin_setjmp places the CFA in the jmpbuf. */
188 return (_Unwind_Word) 0;
191 void
192 _Unwind_SetGR (struct _Unwind_Context *context, int index, _Unwind_Word val)
194 context->fc->data[index] = val;
197 /* Get the call-site index as saved in CONTEXT. */
199 _Unwind_Ptr
200 _Unwind_GetIP (struct _Unwind_Context *context)
202 return context->fc->call_site + 1;
205 /* Set the return landing pad index in CONTEXT. */
207 void
208 _Unwind_SetIP (struct _Unwind_Context *context, _Unwind_Ptr val)
210 context->fc->call_site = val - 1;
213 void *
214 _Unwind_GetLanguageSpecificData (struct _Unwind_Context *context)
216 return context->fc->lsda;
219 _Unwind_Ptr
220 _Unwind_GetRegionStart (struct _Unwind_Context *context __attribute__((unused)) )
222 return 0;
225 void *
226 _Unwind_FindEnclosingFunction (void *pc __attribute__((unused)))
228 return NULL;
231 #ifndef __ia64__
232 _Unwind_Ptr
233 _Unwind_GetDataRelBase (struct _Unwind_Context *context __attribute__((unused)) )
235 return 0;
238 _Unwind_Ptr
239 _Unwind_GetTextRelBase (struct _Unwind_Context *context __attribute__((unused)) )
241 return 0;
243 #endif
245 static inline _Unwind_Reason_Code
246 uw_frame_state_for (struct _Unwind_Context *context, _Unwind_FrameState *fs)
248 if (context->fc == NULL)
250 fs->personality = NULL;
251 return _URC_END_OF_STACK;
253 else
255 fs->personality = context->fc->personality;
256 return _URC_NO_REASON;
260 static inline void
261 uw_update_context (struct _Unwind_Context *context,
262 _Unwind_FrameState *fs __attribute__((unused)) )
264 context->fc = context->fc->prev;
267 static inline void
268 uw_init_context (struct _Unwind_Context *context)
270 context->fc = _Unwind_SjLj_GetContext ();
273 static void __attribute__((noreturn))
274 uw_install_context (struct _Unwind_Context *current __attribute__((unused)),
275 struct _Unwind_Context *target)
277 _Unwind_SjLj_SetContext (target->fc);
278 longjmp (target->fc->jbuf, 1);
281 static inline _Unwind_Ptr
282 uw_identify_context (struct _Unwind_Context *context)
284 return (_Unwind_Ptr) context->fc;
288 /* Play games with unwind symbols so that we can have call frame
289 and sjlj symbols in the same shared library. Not that you can
290 use them simultaneously... */
291 #define _Unwind_RaiseException _Unwind_SjLj_RaiseException
292 #define _Unwind_ForcedUnwind _Unwind_SjLj_ForcedUnwind
293 #define _Unwind_Resume _Unwind_SjLj_Resume
294 #define _Unwind_Resume_or_Rethrow _Unwind_SjLj_Resume_or_Rethrow
296 #include "unwind.inc"
298 #endif /* USING_SJLJ_EXCEPTIONS */