Commit | Line | Data |
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dbb605f5 | 1 | /* Copyright (C) 1995,1996,1998,2000,2001,2004, 2006, 2008 Free Software Foundation, Inc. |
0f2d19dd | 2 | * |
73be1d9e MV |
3 | * This library is free software; you can redistribute it and/or |
4 | * modify it under the terms of the GNU Lesser General Public | |
5 | * License as published by the Free Software Foundation; either | |
6 | * version 2.1 of the License, or (at your option) any later version. | |
0f2d19dd | 7 | * |
73be1d9e MV |
8 | * This library is distributed in the hope that it will be useful, |
9 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
10 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
11 | * Lesser General Public License for more details. | |
0f2d19dd | 12 | * |
73be1d9e MV |
13 | * You should have received a copy of the GNU Lesser General Public |
14 | * License along with this library; if not, write to the Free Software | |
92205699 | 15 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
73be1d9e | 16 | */ |
1bbd0b84 | 17 | |
1bbd0b84 | 18 | |
0f2d19dd | 19 | \f |
dbb605f5 LC |
20 | #ifdef HAVE_CONFIG_H |
21 | # include <config.h> | |
22 | #endif | |
0f2d19dd | 23 | |
bbd43f03 RB |
24 | #include "libguile/_scm.h" |
25 | ||
13070bd3 | 26 | #include <string.h> |
8b7f0bb3 | 27 | #include <stdio.h> |
13070bd3 | 28 | |
8b7f0bb3 | 29 | #include "libguile/async.h" |
d0f6ceb8 | 30 | #include "libguile/debug.h" |
a0599745 MD |
31 | #include "libguile/root.h" |
32 | #include "libguile/stackchk.h" | |
5f144b10 GH |
33 | #include "libguile/smob.h" |
34 | #include "libguile/ports.h" | |
35 | #include "libguile/dynwind.h" | |
ce212434 | 36 | #include "libguile/values.h" |
9de87eea | 37 | #include "libguile/eval.h" |
5f144b10 | 38 | |
db4b4ca6 | 39 | #include "libguile/validate.h" |
a0599745 | 40 | #include "libguile/continuations.h" |
01c8a3dd | 41 | |
0f2d19dd JB |
42 | \f |
43 | ||
44 | /* {Continuations} | |
45 | */ | |
46 | ||
92c2555f | 47 | scm_t_bits scm_tc16_continuation; |
0f2d19dd | 48 | |
e841c3e0 KN |
49 | static SCM |
50 | continuation_mark (SCM obj) | |
5f144b10 | 51 | { |
92c2555f | 52 | scm_t_contregs *continuation = SCM_CONTREGS (obj); |
01c8a3dd | 53 | |
9de87eea | 54 | scm_gc_mark (continuation->root); |
5f144b10 GH |
55 | scm_gc_mark (continuation->throw_value); |
56 | scm_mark_locations (continuation->stack, continuation->num_stack_items); | |
193297d8 RB |
57 | #ifdef __ia64__ |
58 | if (continuation->backing_store) | |
59 | scm_mark_locations (continuation->backing_store, | |
60 | continuation->backing_store_size / | |
61 | sizeof (SCM_STACKITEM)); | |
62 | #endif /* __ia64__ */ | |
5f144b10 GH |
63 | return continuation->dynenv; |
64 | } | |
01c8a3dd | 65 | |
1be6b49c | 66 | static size_t |
e841c3e0 | 67 | continuation_free (SCM obj) |
5f144b10 | 68 | { |
92c2555f | 69 | scm_t_contregs *continuation = SCM_CONTREGS (obj); |
9de87eea | 70 | /* stack array size is 1 if num_stack_items is 0. */ |
1be6b49c | 71 | size_t extra_items = (continuation->num_stack_items > 0) |
5f144b10 GH |
72 | ? (continuation->num_stack_items - 1) |
73 | : 0; | |
92c2555f | 74 | size_t bytes_free = sizeof (scm_t_contregs) |
5f144b10 | 75 | + extra_items * sizeof (SCM_STACKITEM); |
193297d8 RB |
76 | |
77 | #ifdef __ia64__ | |
4c9419ac MV |
78 | scm_gc_free (continuation->backing_store, continuation->backing_store_size, |
79 | "continuation backing store"); | |
193297d8 | 80 | #endif /* __ia64__ */ |
4c9419ac MV |
81 | scm_gc_free (continuation, bytes_free, "continuation"); |
82 | return 0; | |
5f144b10 | 83 | } |
01c8a3dd | 84 | |
e841c3e0 | 85 | static int |
e81d98ec | 86 | continuation_print (SCM obj, SCM port, scm_print_state *state SCM_UNUSED) |
5f144b10 | 87 | { |
92c2555f | 88 | scm_t_contregs *continuation = SCM_CONTREGS (obj); |
5f144b10 GH |
89 | |
90 | scm_puts ("#<continuation ", port); | |
91 | scm_intprint (continuation->num_stack_items, 10, port); | |
92 | scm_puts (" @ ", port); | |
0345e278 | 93 | scm_uintprint (SCM_CELL_WORD_1 (obj), 16, port); |
5f144b10 GH |
94 | scm_putc ('>', port); |
95 | return 1; | |
96 | } | |
1cc91f1b | 97 | |
5f144b10 GH |
98 | /* this may return more than once: the first time with the escape |
99 | procedure, then subsequently with the value to be passed to the | |
100 | continuation. */ | |
101 | #define FUNC_NAME "scm_make_continuation" | |
0f2d19dd | 102 | SCM |
5f144b10 | 103 | scm_make_continuation (int *first) |
0f2d19dd | 104 | { |
9de87eea MV |
105 | scm_i_thread *thread = SCM_I_CURRENT_THREAD; |
106 | SCM cont; | |
92c2555f | 107 | scm_t_contregs *continuation; |
c014a02e | 108 | long stack_size; |
01c8a3dd | 109 | SCM_STACKITEM * src; |
0f2d19dd | 110 | |
0f2d19dd | 111 | SCM_FLUSH_REGISTER_WINDOWS; |
9de87eea | 112 | stack_size = scm_stack_size (thread->continuation_base); |
4c9419ac MV |
113 | continuation = scm_gc_malloc (sizeof (scm_t_contregs) |
114 | + (stack_size - 1) * sizeof (SCM_STACKITEM), | |
115 | "continuation"); | |
5f144b10 | 116 | continuation->num_stack_items = stack_size; |
9de87eea | 117 | continuation->dynenv = scm_i_dynwinds (); |
5f144b10 | 118 | continuation->throw_value = SCM_EOL; |
9de87eea MV |
119 | continuation->root = thread->continuation_root; |
120 | continuation->dframe = scm_i_last_debug_frame (); | |
121 | src = thread->continuation_base; | |
5f144b10 | 122 | SCM_NEWSMOB (cont, scm_tc16_continuation, continuation); |
01c8a3dd | 123 | |
4ccb2cd2 | 124 | #if ! SCM_STACK_GROWS_UP |
5f144b10 GH |
125 | src -= stack_size; |
126 | #endif | |
5c5c27dc | 127 | continuation->offset = continuation->stack - src; |
5f144b10 GH |
128 | memcpy (continuation->stack, src, sizeof (SCM_STACKITEM) * stack_size); |
129 | ||
346e4402 NJ |
130 | *first = !setjmp (continuation->jmpbuf); |
131 | if (*first) | |
193297d8 | 132 | { |
346e4402 | 133 | #ifdef __ia64__ |
9a5fa6e9 | 134 | continuation->backing_store_size = |
346e4402 | 135 | (char *) scm_ia64_ar_bsp(&continuation->jmpbuf.ctx) |
9a5fa6e9 | 136 | - |
346e4402 | 137 | (char *) thread->register_backing_store_base; |
193297d8 RB |
138 | continuation->backing_store = NULL; |
139 | continuation->backing_store = | |
4c9419ac MV |
140 | scm_gc_malloc (continuation->backing_store_size, |
141 | "continuation backing store"); | |
193297d8 | 142 | memcpy (continuation->backing_store, |
346e4402 | 143 | (void *) thread->register_backing_store_base, |
193297d8 | 144 | continuation->backing_store_size); |
346e4402 | 145 | #endif /* __ia64__ */ |
193297d8 RB |
146 | return cont; |
147 | } | |
148 | else | |
149 | { | |
3c468478 | 150 | SCM ret = continuation->throw_value; |
3c468478 MV |
151 | continuation->throw_value = SCM_BOOL_F; |
152 | return ret; | |
193297d8 | 153 | } |
0f2d19dd | 154 | } |
5f144b10 | 155 | #undef FUNC_NAME |
0f2d19dd | 156 | |
d3c6aef9 MV |
157 | |
158 | /* Invoking a continuation proceeds as follows: | |
159 | * | |
160 | * - the stack is made large enough for the called continuation | |
161 | * - the old windchain is unwound down to the branching point | |
162 | * - the continuation stack is copied into place | |
163 | * - the windchain is rewound up to the continuation's context | |
164 | * - the continuation is invoked via longjmp (or setcontext) | |
165 | * | |
166 | * This order is important so that unwind and rewind handlers are run | |
167 | * with their correct stack. | |
168 | */ | |
169 | ||
5f144b10 | 170 | static void scm_dynthrow (SCM, SCM); |
01c8a3dd DH |
171 | |
172 | /* Grow the stack by a fixed amount to provide space to copy in the | |
173 | * continuation. Possibly this function has to be called several times | |
174 | * recursively before enough space is available. Make sure the compiler does | |
175 | * not optimize the growth array away by storing it's address into a global | |
176 | * variable. | |
177 | */ | |
178 | ||
92c2555f | 179 | scm_t_bits scm_i_dummy; |
1cc91f1b | 180 | |
0f2d19dd | 181 | static void |
01c8a3dd DH |
182 | grow_stack (SCM cont, SCM val) |
183 | { | |
92c2555f | 184 | scm_t_bits growth[100]; |
01c8a3dd | 185 | |
92c2555f | 186 | scm_i_dummy = (scm_t_bits) growth; |
01c8a3dd | 187 | scm_dynthrow (cont, val); |
0f2d19dd | 188 | } |
0f2d19dd | 189 | |
1cc91f1b | 190 | |
01c8a3dd DH |
191 | /* Copy the continuation stack into the current stack. Calling functions from |
192 | * within this function is safe, since only stack frames below this function's | |
193 | * own frame are overwritten. Thus, memcpy can be used for best performance. | |
194 | */ | |
d3c6aef9 MV |
195 | |
196 | typedef struct { | |
197 | scm_t_contregs *continuation; | |
198 | SCM_STACKITEM *dst; | |
199 | } copy_stack_data; | |
200 | ||
01c8a3dd | 201 | static void |
d3c6aef9 MV |
202 | copy_stack (void *data) |
203 | { | |
204 | copy_stack_data *d = (copy_stack_data *)data; | |
205 | memcpy (d->dst, d->continuation->stack, | |
206 | sizeof (SCM_STACKITEM) * d->continuation->num_stack_items); | |
346e4402 NJ |
207 | #ifdef __ia64__ |
208 | SCM_I_CURRENT_THREAD->pending_rbs_continuation = d->continuation; | |
209 | #endif | |
d3c6aef9 MV |
210 | } |
211 | ||
212 | static void | |
213 | copy_stack_and_call (scm_t_contregs *continuation, SCM val, | |
5f144b10 | 214 | SCM_STACKITEM * dst) |
0f2d19dd | 215 | { |
d3c6aef9 MV |
216 | long delta; |
217 | copy_stack_data data; | |
218 | ||
9de87eea | 219 | delta = scm_ilength (scm_i_dynwinds ()) - scm_ilength (continuation->dynenv); |
d3c6aef9 MV |
220 | data.continuation = continuation; |
221 | data.dst = dst; | |
14578fa4 | 222 | scm_i_dowinds (continuation->dynenv, delta, copy_stack, &data); |
01c8a3dd | 223 | |
9de87eea | 224 | scm_i_set_last_debug_frame (continuation->dframe); |
01c8a3dd | 225 | |
5f144b10 GH |
226 | continuation->throw_value = val; |
227 | longjmp (continuation->jmpbuf, 1); | |
01c8a3dd DH |
228 | } |
229 | ||
346e4402 NJ |
230 | #ifdef __ia64__ |
231 | void | |
232 | scm_ia64_longjmp (jmp_buf *JB, int VAL) | |
233 | { | |
234 | scm_i_thread *t = SCM_I_CURRENT_THREAD; | |
235 | ||
236 | if (t->pending_rbs_continuation) | |
237 | { | |
238 | memcpy (t->register_backing_store_base, | |
239 | t->pending_rbs_continuation->backing_store, | |
240 | t->pending_rbs_continuation->backing_store_size); | |
241 | t->pending_rbs_continuation = NULL; | |
242 | } | |
243 | setcontext (&JB->ctx); | |
244 | } | |
245 | #endif | |
246 | ||
01c8a3dd DH |
247 | /* Call grow_stack until the stack space is large enough, then, as the current |
248 | * stack frame might get overwritten, let copy_stack_and_call perform the | |
249 | * actual copying and continuation calling. | |
250 | */ | |
251 | static void | |
252 | scm_dynthrow (SCM cont, SCM val) | |
253 | { | |
9de87eea | 254 | scm_i_thread *thread = SCM_I_CURRENT_THREAD; |
92c2555f | 255 | scm_t_contregs *continuation = SCM_CONTREGS (cont); |
9de87eea | 256 | SCM_STACKITEM *dst = thread->continuation_base; |
01c8a3dd DH |
257 | SCM_STACKITEM stack_top_element; |
258 | ||
8b7f0bb3 MV |
259 | if (scm_i_critical_section_level) |
260 | { | |
261 | fprintf (stderr, "continuation invoked from within critical section.\n"); | |
262 | abort (); | |
263 | } | |
264 | ||
4ccb2cd2 | 265 | #if SCM_STACK_GROWS_UP |
5afcf08b | 266 | if (dst + continuation->num_stack_items >= &stack_top_element) |
01c8a3dd | 267 | grow_stack (cont, val); |
0f2d19dd | 268 | #else |
5f144b10 | 269 | dst -= continuation->num_stack_items; |
c8a1bdc4 | 270 | if (dst <= &stack_top_element) |
01c8a3dd | 271 | grow_stack (cont, val); |
0f2d19dd | 272 | #endif /* def SCM_STACK_GROWS_UP */ |
01c8a3dd | 273 | |
5f144b10 GH |
274 | SCM_FLUSH_REGISTER_WINDOWS; |
275 | copy_stack_and_call (continuation, val, dst); | |
0f2d19dd JB |
276 | } |
277 | ||
db4b4ca6 DH |
278 | |
279 | static SCM | |
280 | continuation_apply (SCM cont, SCM args) | |
5f144b10 | 281 | #define FUNC_NAME "continuation_apply" |
0f2d19dd | 282 | { |
9de87eea | 283 | scm_i_thread *thread = SCM_I_CURRENT_THREAD; |
92c2555f | 284 | scm_t_contregs *continuation = SCM_CONTREGS (cont); |
5f144b10 | 285 | |
9de87eea | 286 | if (continuation->root != thread->continuation_root) |
5f144b10 | 287 | { |
9de87eea MV |
288 | SCM_MISC_ERROR |
289 | ("invoking continuation would cross continuation barrier: ~A", | |
290 | scm_list_1 (cont)); | |
5f144b10 | 291 | } |
0f2d19dd | 292 | |
ce212434 | 293 | scm_dynthrow (cont, scm_values (args)); |
0f2d19dd JB |
294 | return SCM_UNSPECIFIED; /* not reached */ |
295 | } | |
5f144b10 | 296 | #undef FUNC_NAME |
0f2d19dd | 297 | |
9de87eea MV |
298 | SCM |
299 | scm_i_with_continuation_barrier (scm_t_catch_body body, | |
300 | void *body_data, | |
301 | scm_t_catch_handler handler, | |
43e01b1e NJ |
302 | void *handler_data, |
303 | scm_t_catch_handler pre_unwind_handler, | |
304 | void *pre_unwind_handler_data) | |
9de87eea MV |
305 | { |
306 | SCM_STACKITEM stack_item; | |
307 | scm_i_thread *thread = SCM_I_CURRENT_THREAD; | |
308 | SCM old_controot; | |
309 | SCM_STACKITEM *old_contbase; | |
310 | scm_t_debug_frame *old_lastframe; | |
311 | SCM result; | |
312 | ||
313 | /* Establish a fresh continuation root. | |
314 | */ | |
315 | old_controot = thread->continuation_root; | |
316 | old_contbase = thread->continuation_base; | |
317 | old_lastframe = thread->last_debug_frame; | |
318 | thread->continuation_root = scm_cons (thread->handle, old_controot); | |
319 | thread->continuation_base = &stack_item; | |
320 | thread->last_debug_frame = NULL; | |
321 | ||
322 | /* Call FUNC inside a catch all. This is now guaranteed to return | |
323 | directly and exactly once. | |
324 | */ | |
43e01b1e NJ |
325 | result = scm_c_catch (SCM_BOOL_T, |
326 | body, body_data, | |
327 | handler, handler_data, | |
328 | pre_unwind_handler, pre_unwind_handler_data); | |
9de87eea MV |
329 | |
330 | /* Return to old continuation root. | |
331 | */ | |
332 | thread->last_debug_frame = old_lastframe; | |
333 | thread->continuation_base = old_contbase; | |
334 | thread->continuation_root = old_controot; | |
335 | ||
336 | return result; | |
337 | } | |
338 | ||
339 | struct c_data { | |
340 | void *(*func) (void *); | |
341 | void *data; | |
342 | void *result; | |
343 | }; | |
344 | ||
345 | static SCM | |
346 | c_body (void *d) | |
347 | { | |
348 | struct c_data *data = (struct c_data *)d; | |
349 | data->result = data->func (data->data); | |
350 | return SCM_UNSPECIFIED; | |
351 | } | |
352 | ||
353 | static SCM | |
354 | c_handler (void *d, SCM tag, SCM args) | |
355 | { | |
356 | struct c_data *data = (struct c_data *)d; | |
9de87eea MV |
357 | data->result = NULL; |
358 | return SCM_UNSPECIFIED; | |
359 | } | |
360 | ||
361 | void * | |
362 | scm_c_with_continuation_barrier (void *(*func) (void *), void *data) | |
363 | { | |
364 | struct c_data c_data; | |
365 | c_data.func = func; | |
366 | c_data.data = data; | |
367 | scm_i_with_continuation_barrier (c_body, &c_data, | |
43e01b1e NJ |
368 | c_handler, &c_data, |
369 | scm_handle_by_message_noexit, NULL); | |
9de87eea MV |
370 | return c_data.result; |
371 | } | |
372 | ||
373 | struct scm_data { | |
374 | SCM proc; | |
375 | }; | |
376 | ||
377 | static SCM | |
378 | scm_body (void *d) | |
379 | { | |
380 | struct scm_data *data = (struct scm_data *)d; | |
381 | return scm_call_0 (data->proc); | |
382 | } | |
383 | ||
384 | static SCM | |
385 | scm_handler (void *d, SCM tag, SCM args) | |
386 | { | |
9de87eea MV |
387 | return SCM_BOOL_F; |
388 | } | |
389 | ||
390 | SCM_DEFINE (scm_with_continuation_barrier, "with-continuation-barrier", 1,0,0, | |
391 | (SCM proc), | |
69d2000d MV |
392 | "Call @var{proc} and return its result. Do not allow the invocation of\n" |
393 | "continuations that would leave or enter the dynamic extent of the call\n" | |
394 | "to @code{with-continuation-barrier}. Such an attempt causes an error\n" | |
395 | "to be signaled.\n" | |
396 | "\n" | |
397 | "Throws (such as errors) that are not caught from within @var{proc} are\n" | |
398 | "caught by @code{with-continuation-barrier}. In that case, a short\n" | |
399 | "message is printed to the current error port and @code{#f} is returned.\n" | |
400 | "\n" | |
401 | "Thus, @code{with-continuation-barrier} returns exactly once.\n") | |
9de87eea MV |
402 | #define FUNC_NAME s_scm_with_continuation_barrier |
403 | { | |
404 | struct scm_data scm_data; | |
405 | scm_data.proc = proc; | |
406 | return scm_i_with_continuation_barrier (scm_body, &scm_data, | |
43e01b1e NJ |
407 | scm_handler, &scm_data, |
408 | scm_handle_by_message_noexit, NULL); | |
9de87eea MV |
409 | } |
410 | #undef FUNC_NAME | |
db4b4ca6 | 411 | |
0f2d19dd JB |
412 | void |
413 | scm_init_continuations () | |
0f2d19dd | 414 | { |
5f144b10 GH |
415 | scm_tc16_continuation = scm_make_smob_type ("continuation", 0); |
416 | scm_set_smob_mark (scm_tc16_continuation, continuation_mark); | |
417 | scm_set_smob_free (scm_tc16_continuation, continuation_free); | |
418 | scm_set_smob_print (scm_tc16_continuation, continuation_print); | |
419 | scm_set_smob_apply (scm_tc16_continuation, continuation_apply, 0, 0, 1); | |
a0599745 | 420 | #include "libguile/continuations.x" |
0f2d19dd JB |
421 | } |
422 | ||
89e00824 ML |
423 | /* |
424 | Local Variables: | |
425 | c-file-style: "gnu" | |
426 | End: | |
427 | */ |