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" |
bfffd258 | 38 | #include "libguile/vm.h" |
5f144b10 | 39 | |
db4b4ca6 | 40 | #include "libguile/validate.h" |
a0599745 | 41 | #include "libguile/continuations.h" |
01c8a3dd | 42 | |
0f2d19dd JB |
43 | \f |
44 | ||
45 | /* {Continuations} | |
46 | */ | |
47 | ||
92c2555f | 48 | scm_t_bits scm_tc16_continuation; |
0f2d19dd | 49 | |
e841c3e0 KN |
50 | static SCM |
51 | continuation_mark (SCM obj) | |
5f144b10 | 52 | { |
92c2555f | 53 | scm_t_contregs *continuation = SCM_CONTREGS (obj); |
01c8a3dd | 54 | |
9de87eea | 55 | scm_gc_mark (continuation->root); |
5f144b10 | 56 | scm_gc_mark (continuation->throw_value); |
7ff01700 | 57 | scm_gc_mark (continuation->vm_conts); |
5f144b10 | 58 | scm_mark_locations (continuation->stack, continuation->num_stack_items); |
193297d8 RB |
59 | #ifdef __ia64__ |
60 | if (continuation->backing_store) | |
61 | scm_mark_locations (continuation->backing_store, | |
62 | continuation->backing_store_size / | |
63 | sizeof (SCM_STACKITEM)); | |
64 | #endif /* __ia64__ */ | |
5f144b10 GH |
65 | return continuation->dynenv; |
66 | } | |
01c8a3dd | 67 | |
1be6b49c | 68 | static size_t |
e841c3e0 | 69 | continuation_free (SCM obj) |
5f144b10 | 70 | { |
92c2555f | 71 | scm_t_contregs *continuation = SCM_CONTREGS (obj); |
9de87eea | 72 | /* stack array size is 1 if num_stack_items is 0. */ |
1be6b49c | 73 | size_t extra_items = (continuation->num_stack_items > 0) |
5f144b10 GH |
74 | ? (continuation->num_stack_items - 1) |
75 | : 0; | |
92c2555f | 76 | size_t bytes_free = sizeof (scm_t_contregs) |
5f144b10 | 77 | + extra_items * sizeof (SCM_STACKITEM); |
193297d8 RB |
78 | |
79 | #ifdef __ia64__ | |
4c9419ac MV |
80 | scm_gc_free (continuation->backing_store, continuation->backing_store_size, |
81 | "continuation backing store"); | |
193297d8 | 82 | #endif /* __ia64__ */ |
4c9419ac MV |
83 | scm_gc_free (continuation, bytes_free, "continuation"); |
84 | return 0; | |
5f144b10 | 85 | } |
01c8a3dd | 86 | |
e841c3e0 | 87 | static int |
e81d98ec | 88 | continuation_print (SCM obj, SCM port, scm_print_state *state SCM_UNUSED) |
5f144b10 | 89 | { |
92c2555f | 90 | scm_t_contregs *continuation = SCM_CONTREGS (obj); |
5f144b10 GH |
91 | |
92 | scm_puts ("#<continuation ", port); | |
93 | scm_intprint (continuation->num_stack_items, 10, port); | |
94 | scm_puts (" @ ", port); | |
0345e278 | 95 | scm_uintprint (SCM_CELL_WORD_1 (obj), 16, port); |
5f144b10 GH |
96 | scm_putc ('>', port); |
97 | return 1; | |
98 | } | |
1cc91f1b | 99 | |
5f144b10 GH |
100 | /* this may return more than once: the first time with the escape |
101 | procedure, then subsequently with the value to be passed to the | |
102 | continuation. */ | |
103 | #define FUNC_NAME "scm_make_continuation" | |
0f2d19dd | 104 | SCM |
5f144b10 | 105 | scm_make_continuation (int *first) |
0f2d19dd | 106 | { |
9de87eea MV |
107 | scm_i_thread *thread = SCM_I_CURRENT_THREAD; |
108 | SCM cont; | |
92c2555f | 109 | scm_t_contregs *continuation; |
c014a02e | 110 | long stack_size; |
01c8a3dd | 111 | SCM_STACKITEM * src; |
0f2d19dd | 112 | |
0f2d19dd | 113 | SCM_FLUSH_REGISTER_WINDOWS; |
9de87eea | 114 | stack_size = scm_stack_size (thread->continuation_base); |
4c9419ac MV |
115 | continuation = scm_gc_malloc (sizeof (scm_t_contregs) |
116 | + (stack_size - 1) * sizeof (SCM_STACKITEM), | |
117 | "continuation"); | |
5f144b10 | 118 | continuation->num_stack_items = stack_size; |
9de87eea | 119 | continuation->dynenv = scm_i_dynwinds (); |
5f144b10 | 120 | continuation->throw_value = SCM_EOL; |
9de87eea MV |
121 | continuation->root = thread->continuation_root; |
122 | continuation->dframe = scm_i_last_debug_frame (); | |
123 | src = thread->continuation_base; | |
5f144b10 | 124 | SCM_NEWSMOB (cont, scm_tc16_continuation, continuation); |
01c8a3dd | 125 | |
4ccb2cd2 | 126 | #if ! SCM_STACK_GROWS_UP |
5f144b10 GH |
127 | src -= stack_size; |
128 | #endif | |
5c5c27dc | 129 | continuation->offset = continuation->stack - src; |
5f144b10 | 130 | memcpy (continuation->stack, src, sizeof (SCM_STACKITEM) * stack_size); |
bfffd258 | 131 | continuation->vm_conts = scm_vm_capture_continuations (); |
5f144b10 | 132 | |
346e4402 NJ |
133 | *first = !setjmp (continuation->jmpbuf); |
134 | if (*first) | |
193297d8 | 135 | { |
346e4402 | 136 | #ifdef __ia64__ |
9a5fa6e9 | 137 | continuation->backing_store_size = |
346e4402 | 138 | (char *) scm_ia64_ar_bsp(&continuation->jmpbuf.ctx) |
9a5fa6e9 | 139 | - |
346e4402 | 140 | (char *) thread->register_backing_store_base; |
193297d8 RB |
141 | continuation->backing_store = NULL; |
142 | continuation->backing_store = | |
4c9419ac MV |
143 | scm_gc_malloc (continuation->backing_store_size, |
144 | "continuation backing store"); | |
193297d8 | 145 | memcpy (continuation->backing_store, |
346e4402 | 146 | (void *) thread->register_backing_store_base, |
193297d8 | 147 | continuation->backing_store_size); |
346e4402 | 148 | #endif /* __ia64__ */ |
193297d8 RB |
149 | return cont; |
150 | } | |
151 | else | |
152 | { | |
3c468478 | 153 | SCM ret = continuation->throw_value; |
3c468478 MV |
154 | continuation->throw_value = SCM_BOOL_F; |
155 | return ret; | |
193297d8 | 156 | } |
0f2d19dd | 157 | } |
5f144b10 | 158 | #undef FUNC_NAME |
0f2d19dd | 159 | |
d3c6aef9 MV |
160 | |
161 | /* Invoking a continuation proceeds as follows: | |
162 | * | |
163 | * - the stack is made large enough for the called continuation | |
164 | * - the old windchain is unwound down to the branching point | |
165 | * - the continuation stack is copied into place | |
166 | * - the windchain is rewound up to the continuation's context | |
167 | * - the continuation is invoked via longjmp (or setcontext) | |
168 | * | |
169 | * This order is important so that unwind and rewind handlers are run | |
170 | * with their correct stack. | |
171 | */ | |
172 | ||
5f144b10 | 173 | static void scm_dynthrow (SCM, SCM); |
01c8a3dd DH |
174 | |
175 | /* Grow the stack by a fixed amount to provide space to copy in the | |
176 | * continuation. Possibly this function has to be called several times | |
177 | * recursively before enough space is available. Make sure the compiler does | |
178 | * not optimize the growth array away by storing it's address into a global | |
179 | * variable. | |
180 | */ | |
181 | ||
92c2555f | 182 | scm_t_bits scm_i_dummy; |
1cc91f1b | 183 | |
0f2d19dd | 184 | static void |
01c8a3dd DH |
185 | grow_stack (SCM cont, SCM val) |
186 | { | |
92c2555f | 187 | scm_t_bits growth[100]; |
01c8a3dd | 188 | |
92c2555f | 189 | scm_i_dummy = (scm_t_bits) growth; |
01c8a3dd | 190 | scm_dynthrow (cont, val); |
0f2d19dd | 191 | } |
0f2d19dd | 192 | |
1cc91f1b | 193 | |
01c8a3dd DH |
194 | /* Copy the continuation stack into the current stack. Calling functions from |
195 | * within this function is safe, since only stack frames below this function's | |
196 | * own frame are overwritten. Thus, memcpy can be used for best performance. | |
197 | */ | |
d3c6aef9 MV |
198 | |
199 | typedef struct { | |
200 | scm_t_contregs *continuation; | |
201 | SCM_STACKITEM *dst; | |
202 | } copy_stack_data; | |
203 | ||
01c8a3dd | 204 | static void |
d3c6aef9 MV |
205 | copy_stack (void *data) |
206 | { | |
207 | copy_stack_data *d = (copy_stack_data *)data; | |
208 | memcpy (d->dst, d->continuation->stack, | |
209 | sizeof (SCM_STACKITEM) * d->continuation->num_stack_items); | |
bfffd258 | 210 | scm_vm_reinstate_continuations (d->continuation->vm_conts); |
346e4402 NJ |
211 | #ifdef __ia64__ |
212 | SCM_I_CURRENT_THREAD->pending_rbs_continuation = d->continuation; | |
213 | #endif | |
d3c6aef9 MV |
214 | } |
215 | ||
216 | static void | |
217 | copy_stack_and_call (scm_t_contregs *continuation, SCM val, | |
5f144b10 | 218 | SCM_STACKITEM * dst) |
0f2d19dd | 219 | { |
d3c6aef9 MV |
220 | long delta; |
221 | copy_stack_data data; | |
222 | ||
9de87eea | 223 | delta = scm_ilength (scm_i_dynwinds ()) - scm_ilength (continuation->dynenv); |
d3c6aef9 MV |
224 | data.continuation = continuation; |
225 | data.dst = dst; | |
14578fa4 | 226 | scm_i_dowinds (continuation->dynenv, delta, copy_stack, &data); |
01c8a3dd | 227 | |
9de87eea | 228 | scm_i_set_last_debug_frame (continuation->dframe); |
01c8a3dd | 229 | |
5f144b10 GH |
230 | continuation->throw_value = val; |
231 | longjmp (continuation->jmpbuf, 1); | |
01c8a3dd DH |
232 | } |
233 | ||
346e4402 NJ |
234 | #ifdef __ia64__ |
235 | void | |
236 | scm_ia64_longjmp (jmp_buf *JB, int VAL) | |
237 | { | |
238 | scm_i_thread *t = SCM_I_CURRENT_THREAD; | |
239 | ||
240 | if (t->pending_rbs_continuation) | |
241 | { | |
242 | memcpy (t->register_backing_store_base, | |
243 | t->pending_rbs_continuation->backing_store, | |
244 | t->pending_rbs_continuation->backing_store_size); | |
245 | t->pending_rbs_continuation = NULL; | |
246 | } | |
247 | setcontext (&JB->ctx); | |
248 | } | |
249 | #endif | |
250 | ||
01c8a3dd DH |
251 | /* Call grow_stack until the stack space is large enough, then, as the current |
252 | * stack frame might get overwritten, let copy_stack_and_call perform the | |
253 | * actual copying and continuation calling. | |
254 | */ | |
255 | static void | |
256 | scm_dynthrow (SCM cont, SCM val) | |
257 | { | |
9de87eea | 258 | scm_i_thread *thread = SCM_I_CURRENT_THREAD; |
92c2555f | 259 | scm_t_contregs *continuation = SCM_CONTREGS (cont); |
9de87eea | 260 | SCM_STACKITEM *dst = thread->continuation_base; |
01c8a3dd DH |
261 | SCM_STACKITEM stack_top_element; |
262 | ||
8b7f0bb3 MV |
263 | if (scm_i_critical_section_level) |
264 | { | |
265 | fprintf (stderr, "continuation invoked from within critical section.\n"); | |
266 | abort (); | |
267 | } | |
268 | ||
4ccb2cd2 | 269 | #if SCM_STACK_GROWS_UP |
5afcf08b | 270 | if (dst + continuation->num_stack_items >= &stack_top_element) |
01c8a3dd | 271 | grow_stack (cont, val); |
0f2d19dd | 272 | #else |
5f144b10 | 273 | dst -= continuation->num_stack_items; |
c8a1bdc4 | 274 | if (dst <= &stack_top_element) |
01c8a3dd | 275 | grow_stack (cont, val); |
0f2d19dd | 276 | #endif /* def SCM_STACK_GROWS_UP */ |
01c8a3dd | 277 | |
5f144b10 GH |
278 | SCM_FLUSH_REGISTER_WINDOWS; |
279 | copy_stack_and_call (continuation, val, dst); | |
0f2d19dd JB |
280 | } |
281 | ||
db4b4ca6 DH |
282 | |
283 | static SCM | |
284 | continuation_apply (SCM cont, SCM args) | |
5f144b10 | 285 | #define FUNC_NAME "continuation_apply" |
0f2d19dd | 286 | { |
9de87eea | 287 | scm_i_thread *thread = SCM_I_CURRENT_THREAD; |
92c2555f | 288 | scm_t_contregs *continuation = SCM_CONTREGS (cont); |
5f144b10 | 289 | |
9de87eea | 290 | if (continuation->root != thread->continuation_root) |
5f144b10 | 291 | { |
9de87eea MV |
292 | SCM_MISC_ERROR |
293 | ("invoking continuation would cross continuation barrier: ~A", | |
294 | scm_list_1 (cont)); | |
5f144b10 | 295 | } |
0f2d19dd | 296 | |
ce212434 | 297 | scm_dynthrow (cont, scm_values (args)); |
0f2d19dd JB |
298 | return SCM_UNSPECIFIED; /* not reached */ |
299 | } | |
5f144b10 | 300 | #undef FUNC_NAME |
0f2d19dd | 301 | |
9de87eea MV |
302 | SCM |
303 | scm_i_with_continuation_barrier (scm_t_catch_body body, | |
304 | void *body_data, | |
305 | scm_t_catch_handler handler, | |
43e01b1e NJ |
306 | void *handler_data, |
307 | scm_t_catch_handler pre_unwind_handler, | |
308 | void *pre_unwind_handler_data) | |
9de87eea MV |
309 | { |
310 | SCM_STACKITEM stack_item; | |
311 | scm_i_thread *thread = SCM_I_CURRENT_THREAD; | |
312 | SCM old_controot; | |
313 | SCM_STACKITEM *old_contbase; | |
314 | scm_t_debug_frame *old_lastframe; | |
315 | SCM result; | |
316 | ||
317 | /* Establish a fresh continuation root. | |
318 | */ | |
319 | old_controot = thread->continuation_root; | |
320 | old_contbase = thread->continuation_base; | |
321 | old_lastframe = thread->last_debug_frame; | |
322 | thread->continuation_root = scm_cons (thread->handle, old_controot); | |
323 | thread->continuation_base = &stack_item; | |
324 | thread->last_debug_frame = NULL; | |
325 | ||
326 | /* Call FUNC inside a catch all. This is now guaranteed to return | |
327 | directly and exactly once. | |
328 | */ | |
43e01b1e NJ |
329 | result = scm_c_catch (SCM_BOOL_T, |
330 | body, body_data, | |
331 | handler, handler_data, | |
332 | pre_unwind_handler, pre_unwind_handler_data); | |
9de87eea MV |
333 | |
334 | /* Return to old continuation root. | |
335 | */ | |
336 | thread->last_debug_frame = old_lastframe; | |
337 | thread->continuation_base = old_contbase; | |
338 | thread->continuation_root = old_controot; | |
339 | ||
340 | return result; | |
341 | } | |
342 | ||
343 | struct c_data { | |
344 | void *(*func) (void *); | |
345 | void *data; | |
346 | void *result; | |
347 | }; | |
348 | ||
349 | static SCM | |
350 | c_body (void *d) | |
351 | { | |
352 | struct c_data *data = (struct c_data *)d; | |
353 | data->result = data->func (data->data); | |
354 | return SCM_UNSPECIFIED; | |
355 | } | |
356 | ||
357 | static SCM | |
358 | c_handler (void *d, SCM tag, SCM args) | |
359 | { | |
360 | struct c_data *data = (struct c_data *)d; | |
9de87eea MV |
361 | data->result = NULL; |
362 | return SCM_UNSPECIFIED; | |
363 | } | |
364 | ||
365 | void * | |
366 | scm_c_with_continuation_barrier (void *(*func) (void *), void *data) | |
367 | { | |
368 | struct c_data c_data; | |
369 | c_data.func = func; | |
370 | c_data.data = data; | |
371 | scm_i_with_continuation_barrier (c_body, &c_data, | |
43e01b1e NJ |
372 | c_handler, &c_data, |
373 | scm_handle_by_message_noexit, NULL); | |
9de87eea MV |
374 | return c_data.result; |
375 | } | |
376 | ||
377 | struct scm_data { | |
378 | SCM proc; | |
379 | }; | |
380 | ||
381 | static SCM | |
382 | scm_body (void *d) | |
383 | { | |
384 | struct scm_data *data = (struct scm_data *)d; | |
385 | return scm_call_0 (data->proc); | |
386 | } | |
387 | ||
388 | static SCM | |
389 | scm_handler (void *d, SCM tag, SCM args) | |
390 | { | |
9de87eea MV |
391 | return SCM_BOOL_F; |
392 | } | |
393 | ||
394 | SCM_DEFINE (scm_with_continuation_barrier, "with-continuation-barrier", 1,0,0, | |
395 | (SCM proc), | |
69d2000d MV |
396 | "Call @var{proc} and return its result. Do not allow the invocation of\n" |
397 | "continuations that would leave or enter the dynamic extent of the call\n" | |
398 | "to @code{with-continuation-barrier}. Such an attempt causes an error\n" | |
399 | "to be signaled.\n" | |
400 | "\n" | |
401 | "Throws (such as errors) that are not caught from within @var{proc} are\n" | |
402 | "caught by @code{with-continuation-barrier}. In that case, a short\n" | |
403 | "message is printed to the current error port and @code{#f} is returned.\n" | |
404 | "\n" | |
405 | "Thus, @code{with-continuation-barrier} returns exactly once.\n") | |
9de87eea MV |
406 | #define FUNC_NAME s_scm_with_continuation_barrier |
407 | { | |
408 | struct scm_data scm_data; | |
409 | scm_data.proc = proc; | |
410 | return scm_i_with_continuation_barrier (scm_body, &scm_data, | |
43e01b1e NJ |
411 | scm_handler, &scm_data, |
412 | scm_handle_by_message_noexit, NULL); | |
9de87eea MV |
413 | } |
414 | #undef FUNC_NAME | |
db4b4ca6 | 415 | |
0f2d19dd JB |
416 | void |
417 | scm_init_continuations () | |
0f2d19dd | 418 | { |
5f144b10 GH |
419 | scm_tc16_continuation = scm_make_smob_type ("continuation", 0); |
420 | scm_set_smob_mark (scm_tc16_continuation, continuation_mark); | |
421 | scm_set_smob_free (scm_tc16_continuation, continuation_free); | |
422 | scm_set_smob_print (scm_tc16_continuation, continuation_print); | |
423 | scm_set_smob_apply (scm_tc16_continuation, continuation_apply, 0, 0, 1); | |
a0599745 | 424 | #include "libguile/continuations.x" |
0f2d19dd JB |
425 | } |
426 | ||
89e00824 ML |
427 | /* |
428 | Local Variables: | |
429 | c-file-style: "gnu" | |
430 | End: | |
431 | */ |