Use a primop for getting the fields of the AP_STACK rather than an FFI call
[ghc.git] / rts / Interpreter.c
1 /* -----------------------------------------------------------------------------
2 * Bytecode interpreter
3 *
4 * Copyright (c) The GHC Team, 1994-2002.
5 * ---------------------------------------------------------------------------*/
6
7 #include "PosixSource.h"
8 #include "Rts.h"
9 #include "RtsAPI.h"
10 #include "RtsUtils.h"
11 #include "Closures.h"
12 #include "TSO.h"
13 #include "Schedule.h"
14 #include "RtsFlags.h"
15 #include "LdvProfile.h"
16 #include "Updates.h"
17 #include "Sanity.h"
18 #include "Liveness.h"
19
20 #include "Bytecodes.h"
21 #include "Printer.h"
22 #include "Disassembler.h"
23 #include "Interpreter.h"
24
25 #include <string.h> /* for memcpy */
26 #ifdef HAVE_ERRNO_H
27 #include <errno.h>
28 #endif
29
30
31 /* --------------------------------------------------------------------------
32 * The bytecode interpreter
33 * ------------------------------------------------------------------------*/
34
35 /* Gather stats about entry, opcode, opcode-pair frequencies. For
36 tuning the interpreter. */
37
38 /* #define INTERP_STATS */
39
40
41 /* Sp points to the lowest live word on the stack. */
42
43 #define BCO_NEXT instrs[bciPtr++]
44 #define BCO_NEXT_32 (bciPtr += 2, (((StgWord) instrs[bciPtr-2]) << 16) + ((StgWord) instrs[bciPtr-1]))
45 #define BCO_NEXT_64 (bciPtr += 4, (((StgWord) instrs[bciPtr-4]) << 48) + (((StgWord) instrs[bciPtr-3]) << 32) + (((StgWord) instrs[bciPtr-2]) << 16) + ((StgWord) instrs[bciPtr-1]))
46 #if WORD_SIZE_IN_BITS == 32
47 #define BCO_NEXT_WORD BCO_NEXT_32
48 #elif WORD_SIZE_IN_BITS == 64
49 #define BCO_NEXT_WORD BCO_NEXT_64
50 #else
51 #error Cannot cope with WORD_SIZE_IN_BITS being nether 32 nor 64
52 #endif
53 #define BCO_GET_LARGE_ARG ((bci & bci_FLAG_LARGE_ARGS) ? BCO_NEXT_WORD : BCO_NEXT)
54
55 #define BCO_PTR(n) (W_)ptrs[n]
56 #define BCO_LIT(n) literals[n]
57
58 #define LOAD_STACK_POINTERS \
59 Sp = cap->r.rCurrentTSO->sp; \
60 /* We don't change this ... */ \
61 SpLim = cap->r.rCurrentTSO->stack + RESERVED_STACK_WORDS;
62
63 #define SAVE_STACK_POINTERS \
64 cap->r.rCurrentTSO->sp = Sp
65
66 #define RETURN_TO_SCHEDULER(todo,retcode) \
67 SAVE_STACK_POINTERS; \
68 cap->r.rCurrentTSO->what_next = (todo); \
69 threadPaused(cap,cap->r.rCurrentTSO); \
70 cap->r.rRet = (retcode); \
71 return cap;
72
73 #define RETURN_TO_SCHEDULER_NO_PAUSE(todo,retcode) \
74 SAVE_STACK_POINTERS; \
75 cap->r.rCurrentTSO->what_next = (todo); \
76 cap->r.rRet = (retcode); \
77 return cap;
78
79
80 STATIC_INLINE StgPtr
81 allocate_NONUPD (int n_words)
82 {
83 return allocate(stg_max(sizeofW(StgHeader)+MIN_PAYLOAD_SIZE, n_words));
84 }
85
86 rtsBool stop_next_breakpoint = rtsFalse;
87
88 #ifdef INTERP_STATS
89
90 /* Hacky stats, for tuning the interpreter ... */
91 int it_unknown_entries[N_CLOSURE_TYPES];
92 int it_total_unknown_entries;
93 int it_total_entries;
94
95 int it_retto_BCO;
96 int it_retto_UPDATE;
97 int it_retto_other;
98
99 int it_slides;
100 int it_insns;
101 int it_BCO_entries;
102
103 int it_ofreq[27];
104 int it_oofreq[27][27];
105 int it_lastopc;
106
107
108 #define INTERP_TICK(n) (n)++
109
110 void interp_startup ( void )
111 {
112 int i, j;
113 it_retto_BCO = it_retto_UPDATE = it_retto_other = 0;
114 it_total_entries = it_total_unknown_entries = 0;
115 for (i = 0; i < N_CLOSURE_TYPES; i++)
116 it_unknown_entries[i] = 0;
117 it_slides = it_insns = it_BCO_entries = 0;
118 for (i = 0; i < 27; i++) it_ofreq[i] = 0;
119 for (i = 0; i < 27; i++)
120 for (j = 0; j < 27; j++)
121 it_oofreq[i][j] = 0;
122 it_lastopc = 0;
123 }
124
125 void interp_shutdown ( void )
126 {
127 int i, j, k, o_max, i_max, j_max;
128 debugBelch("%d constrs entered -> (%d BCO, %d UPD, %d ??? )\n",
129 it_retto_BCO + it_retto_UPDATE + it_retto_other,
130 it_retto_BCO, it_retto_UPDATE, it_retto_other );
131 debugBelch("%d total entries, %d unknown entries \n",
132 it_total_entries, it_total_unknown_entries);
133 for (i = 0; i < N_CLOSURE_TYPES; i++) {
134 if (it_unknown_entries[i] == 0) continue;
135 debugBelch(" type %2d: unknown entries (%4.1f%%) == %d\n",
136 i, 100.0 * ((double)it_unknown_entries[i]) /
137 ((double)it_total_unknown_entries),
138 it_unknown_entries[i]);
139 }
140 debugBelch("%d insns, %d slides, %d BCO_entries\n",
141 it_insns, it_slides, it_BCO_entries);
142 for (i = 0; i < 27; i++)
143 debugBelch("opcode %2d got %d\n", i, it_ofreq[i] );
144
145 for (k = 1; k < 20; k++) {
146 o_max = 0;
147 i_max = j_max = 0;
148 for (i = 0; i < 27; i++) {
149 for (j = 0; j < 27; j++) {
150 if (it_oofreq[i][j] > o_max) {
151 o_max = it_oofreq[i][j];
152 i_max = i; j_max = j;
153 }
154 }
155 }
156
157 debugBelch("%d: count (%4.1f%%) %6d is %d then %d\n",
158 k, ((double)o_max) * 100.0 / ((double)it_insns), o_max,
159 i_max, j_max );
160 it_oofreq[i_max][j_max] = 0;
161
162 }
163 }
164
165 #else // !INTERP_STATS
166
167 #define INTERP_TICK(n) /* nothing */
168
169 #endif
170
171 static StgWord app_ptrs_itbl[] = {
172 (W_)&stg_ap_p_info,
173 (W_)&stg_ap_pp_info,
174 (W_)&stg_ap_ppp_info,
175 (W_)&stg_ap_pppp_info,
176 (W_)&stg_ap_ppppp_info,
177 (W_)&stg_ap_pppppp_info,
178 };
179
180 HsStablePtr breakPointIOAction; // points to the IO action which is executed on a breakpoint
181 // it is set in main/GHC.hs:runStmt
182
183 Capability *
184 interpretBCO (Capability* cap)
185 {
186 // Use of register here is primarily to make it clear to compilers
187 // that these entities are non-aliasable.
188 register StgPtr Sp; // local state -- stack pointer
189 register StgPtr SpLim; // local state -- stack lim pointer
190 register StgClosure* obj;
191 nat n, m;
192
193 LOAD_STACK_POINTERS;
194
195 // ------------------------------------------------------------------------
196 // Case 1:
197 //
198 // We have a closure to evaluate. Stack looks like:
199 //
200 // | XXXX_info |
201 // +---------------+
202 // Sp | -------------------> closure
203 // +---------------+
204 //
205 if (Sp[0] == (W_)&stg_enter_info) {
206 Sp++;
207 goto eval;
208 }
209
210 // ------------------------------------------------------------------------
211 // Case 2:
212 //
213 // We have a BCO application to perform. Stack looks like:
214 //
215 // | .... |
216 // +---------------+
217 // | arg1 |
218 // +---------------+
219 // | BCO |
220 // +---------------+
221 // Sp | RET_BCO |
222 // +---------------+
223 //
224 else if (Sp[0] == (W_)&stg_apply_interp_info) {
225 obj = (StgClosure *)Sp[1];
226 Sp += 2;
227 goto run_BCO_fun;
228 }
229
230 // ------------------------------------------------------------------------
231 // Case 3:
232 //
233 // We have an unboxed value to return. See comment before
234 // do_return_unboxed, below.
235 //
236 else {
237 goto do_return_unboxed;
238 }
239
240 // Evaluate the object on top of the stack.
241 eval:
242 obj = (StgClosure*)Sp[0]; Sp++;
243
244 eval_obj:
245 INTERP_TICK(it_total_evals);
246
247 IF_DEBUG(interpreter,
248 debugBelch(
249 "\n---------------------------------------------------------------\n");
250 debugBelch("Evaluating: "); printObj(obj);
251 debugBelch("Sp = %p\n", Sp);
252 debugBelch("\n" );
253
254 printStackChunk(Sp,cap->r.rCurrentTSO->stack+cap->r.rCurrentTSO->stack_size);
255 debugBelch("\n\n");
256 );
257
258 IF_DEBUG(sanity,checkStackChunk(Sp, cap->r.rCurrentTSO->stack+cap->r.rCurrentTSO->stack_size));
259
260 switch ( get_itbl(obj)->type ) {
261
262 case IND:
263 case IND_OLDGEN:
264 case IND_PERM:
265 case IND_OLDGEN_PERM:
266 case IND_STATIC:
267 {
268 obj = ((StgInd*)obj)->indirectee;
269 goto eval_obj;
270 }
271
272 case CONSTR:
273 case CONSTR_1_0:
274 case CONSTR_0_1:
275 case CONSTR_2_0:
276 case CONSTR_1_1:
277 case CONSTR_0_2:
278 case CONSTR_STATIC:
279 case CONSTR_NOCAF_STATIC:
280 case FUN:
281 case FUN_1_0:
282 case FUN_0_1:
283 case FUN_2_0:
284 case FUN_1_1:
285 case FUN_0_2:
286 case FUN_STATIC:
287 case PAP:
288 // already in WHNF
289 break;
290
291 case BCO:
292 {
293 ASSERT(((StgBCO *)obj)->arity > 0);
294 break;
295 }
296
297 case AP: /* Copied from stg_AP_entry. */
298 {
299 nat i, words;
300 StgAP *ap;
301
302 ap = (StgAP*)obj;
303 words = ap->n_args;
304
305 // Stack check
306 if (Sp - (words+sizeofW(StgUpdateFrame)) < SpLim) {
307 Sp -= 2;
308 Sp[1] = (W_)obj;
309 Sp[0] = (W_)&stg_enter_info;
310 RETURN_TO_SCHEDULER(ThreadInterpret, StackOverflow);
311 }
312
313 /* Ok; we're safe. Party on. Push an update frame. */
314 Sp -= sizeofW(StgUpdateFrame);
315 {
316 StgUpdateFrame *__frame;
317 __frame = (StgUpdateFrame *)Sp;
318 SET_INFO(__frame, (StgInfoTable *)&stg_upd_frame_info);
319 __frame->updatee = (StgClosure *)(ap);
320 }
321
322 /* Reload the stack */
323 Sp -= words;
324 for (i=0; i < words; i++) {
325 Sp[i] = (W_)ap->payload[i];
326 }
327
328 obj = (StgClosure*)ap->fun;
329 ASSERT(get_itbl(obj)->type == BCO);
330 goto run_BCO_fun;
331 }
332
333 default:
334 #ifdef INTERP_STATS
335 {
336 int j;
337
338 j = get_itbl(obj)->type;
339 ASSERT(j >= 0 && j < N_CLOSURE_TYPES);
340 it_unknown_entries[j]++;
341 it_total_unknown_entries++;
342 }
343 #endif
344 {
345 // Can't handle this object; yield to scheduler
346 IF_DEBUG(interpreter,
347 debugBelch("evaluating unknown closure -- yielding to sched\n");
348 printObj(obj);
349 );
350 Sp -= 2;
351 Sp[1] = (W_)obj;
352 Sp[0] = (W_)&stg_enter_info;
353 RETURN_TO_SCHEDULER_NO_PAUSE(ThreadRunGHC, ThreadYielding);
354 }
355 }
356
357 // ------------------------------------------------------------------------
358 // We now have an evaluated object (obj). The next thing to
359 // do is return it to the stack frame on top of the stack.
360 do_return:
361 ASSERT(closure_HNF(obj));
362
363 IF_DEBUG(interpreter,
364 debugBelch(
365 "\n---------------------------------------------------------------\n");
366 debugBelch("Returning: "); printObj(obj);
367 debugBelch("Sp = %p\n", Sp);
368 debugBelch("\n" );
369 printStackChunk(Sp,cap->r.rCurrentTSO->stack+cap->r.rCurrentTSO->stack_size);
370 debugBelch("\n\n");
371 );
372
373 IF_DEBUG(sanity,checkStackChunk(Sp, cap->r.rCurrentTSO->stack+cap->r.rCurrentTSO->stack_size));
374
375 switch (get_itbl((StgClosure *)Sp)->type) {
376
377 case RET_SMALL: {
378 const StgInfoTable *info;
379
380 // NOTE: not using get_itbl().
381 info = ((StgClosure *)Sp)->header.info;
382 if (info == (StgInfoTable *)&stg_ap_v_info) {
383 n = 1; m = 0; goto do_apply;
384 }
385 if (info == (StgInfoTable *)&stg_ap_f_info) {
386 n = 1; m = 1; goto do_apply;
387 }
388 if (info == (StgInfoTable *)&stg_ap_d_info) {
389 n = 1; m = sizeofW(StgDouble); goto do_apply;
390 }
391 if (info == (StgInfoTable *)&stg_ap_l_info) {
392 n = 1; m = sizeofW(StgInt64); goto do_apply;
393 }
394 if (info == (StgInfoTable *)&stg_ap_n_info) {
395 n = 1; m = 1; goto do_apply;
396 }
397 if (info == (StgInfoTable *)&stg_ap_p_info) {
398 n = 1; m = 1; goto do_apply;
399 }
400 if (info == (StgInfoTable *)&stg_ap_pp_info) {
401 n = 2; m = 2; goto do_apply;
402 }
403 if (info == (StgInfoTable *)&stg_ap_ppp_info) {
404 n = 3; m = 3; goto do_apply;
405 }
406 if (info == (StgInfoTable *)&stg_ap_pppp_info) {
407 n = 4; m = 4; goto do_apply;
408 }
409 if (info == (StgInfoTable *)&stg_ap_ppppp_info) {
410 n = 5; m = 5; goto do_apply;
411 }
412 if (info == (StgInfoTable *)&stg_ap_pppppp_info) {
413 n = 6; m = 6; goto do_apply;
414 }
415 goto do_return_unrecognised;
416 }
417
418 case UPDATE_FRAME:
419 // Returning to an update frame: do the update, pop the update
420 // frame, and continue with the next stack frame.
421 INTERP_TICK(it_retto_UPDATE);
422 UPD_IND(((StgUpdateFrame *)Sp)->updatee, obj);
423 Sp += sizeofW(StgUpdateFrame);
424 goto do_return;
425
426 case RET_BCO:
427 // Returning to an interpreted continuation: put the object on
428 // the stack, and start executing the BCO.
429 INTERP_TICK(it_retto_BCO);
430 Sp--;
431 Sp[0] = (W_)obj;
432 obj = (StgClosure*)Sp[2];
433 ASSERT(get_itbl(obj)->type == BCO);
434 goto run_BCO_return;
435
436 default:
437 do_return_unrecognised:
438 {
439 // Can't handle this return address; yield to scheduler
440 INTERP_TICK(it_retto_other);
441 IF_DEBUG(interpreter,
442 debugBelch("returning to unknown frame -- yielding to sched\n");
443 printStackChunk(Sp,cap->r.rCurrentTSO->stack+cap->r.rCurrentTSO->stack_size);
444 );
445 Sp -= 2;
446 Sp[1] = (W_)obj;
447 Sp[0] = (W_)&stg_enter_info;
448 RETURN_TO_SCHEDULER_NO_PAUSE(ThreadRunGHC, ThreadYielding);
449 }
450 }
451
452 // -------------------------------------------------------------------------
453 // Returning an unboxed value. The stack looks like this:
454 //
455 // | .... |
456 // +---------------+
457 // | fv2 |
458 // +---------------+
459 // | fv1 |
460 // +---------------+
461 // | BCO |
462 // +---------------+
463 // | stg_ctoi_ret_ |
464 // +---------------+
465 // | retval |
466 // +---------------+
467 // | XXXX_info |
468 // +---------------+
469 //
470 // where XXXX_info is one of the stg_gc_unbx_r1_info family.
471 //
472 // We're only interested in the case when the real return address
473 // is a BCO; otherwise we'll return to the scheduler.
474
475 do_return_unboxed:
476 {
477 int offset;
478
479 ASSERT( Sp[0] == (W_)&stg_gc_unbx_r1_info
480 || Sp[0] == (W_)&stg_gc_unpt_r1_info
481 || Sp[0] == (W_)&stg_gc_f1_info
482 || Sp[0] == (W_)&stg_gc_d1_info
483 || Sp[0] == (W_)&stg_gc_l1_info
484 || Sp[0] == (W_)&stg_gc_void_info // VoidRep
485 );
486
487 // get the offset of the stg_ctoi_ret_XXX itbl
488 offset = stack_frame_sizeW((StgClosure *)Sp);
489
490 switch (get_itbl((StgClosure *)Sp+offset)->type) {
491
492 case RET_BCO:
493 // Returning to an interpreted continuation: put the object on
494 // the stack, and start executing the BCO.
495 INTERP_TICK(it_retto_BCO);
496 obj = (StgClosure*)Sp[offset+1];
497 ASSERT(get_itbl(obj)->type == BCO);
498 goto run_BCO_return_unboxed;
499
500 default:
501 {
502 // Can't handle this return address; yield to scheduler
503 INTERP_TICK(it_retto_other);
504 IF_DEBUG(interpreter,
505 debugBelch("returning to unknown frame -- yielding to sched\n");
506 printStackChunk(Sp,cap->r.rCurrentTSO->stack+cap->r.rCurrentTSO->stack_size);
507 );
508 RETURN_TO_SCHEDULER_NO_PAUSE(ThreadRunGHC, ThreadYielding);
509 }
510 }
511 }
512 // not reached.
513
514
515 // -------------------------------------------------------------------------
516 // Application...
517
518 do_apply:
519 // we have a function to apply (obj), and n arguments taking up m
520 // words on the stack. The info table (stg_ap_pp_info or whatever)
521 // is on top of the arguments on the stack.
522 {
523 switch (get_itbl(obj)->type) {
524
525 case PAP: {
526 StgPAP *pap;
527 nat i, arity;
528
529 pap = (StgPAP *)obj;
530
531 // we only cope with PAPs whose function is a BCO
532 if (get_itbl(pap->fun)->type != BCO) {
533 goto defer_apply_to_sched;
534 }
535
536 Sp++;
537 arity = pap->arity;
538 ASSERT(arity > 0);
539 if (arity < n) {
540 // n must be greater than 1, and the only kinds of
541 // application we support with more than one argument
542 // are all pointers...
543 //
544 // Shuffle the args for this function down, and put
545 // the appropriate info table in the gap.
546 for (i = 0; i < arity; i++) {
547 Sp[(int)i-1] = Sp[i];
548 // ^^^^^ careful, i-1 might be negative, but i in unsigned
549 }
550 Sp[arity-1] = app_ptrs_itbl[n-arity-1];
551 Sp--;
552 // unpack the PAP's arguments onto the stack
553 Sp -= pap->n_args;
554 for (i = 0; i < pap->n_args; i++) {
555 Sp[i] = (W_)pap->payload[i];
556 }
557 obj = pap->fun;
558 goto run_BCO_fun;
559 }
560 else if (arity == n) {
561 Sp -= pap->n_args;
562 for (i = 0; i < pap->n_args; i++) {
563 Sp[i] = (W_)pap->payload[i];
564 }
565 obj = pap->fun;
566 goto run_BCO_fun;
567 }
568 else /* arity > n */ {
569 // build a new PAP and return it.
570 StgPAP *new_pap;
571 new_pap = (StgPAP *)allocate(PAP_sizeW(pap->n_args + m));
572 SET_HDR(new_pap,&stg_PAP_info,CCCS);
573 new_pap->arity = pap->arity - n;
574 new_pap->n_args = pap->n_args + m;
575 new_pap->fun = pap->fun;
576 for (i = 0; i < pap->n_args; i++) {
577 new_pap->payload[i] = pap->payload[i];
578 }
579 for (i = 0; i < m; i++) {
580 new_pap->payload[pap->n_args + i] = (StgClosure *)Sp[i];
581 }
582 obj = (StgClosure *)new_pap;
583 Sp += m;
584 goto do_return;
585 }
586 }
587
588 case BCO: {
589 nat arity, i;
590
591 Sp++;
592 arity = ((StgBCO *)obj)->arity;
593 ASSERT(arity > 0);
594 if (arity < n) {
595 // n must be greater than 1, and the only kinds of
596 // application we support with more than one argument
597 // are all pointers...
598 //
599 // Shuffle the args for this function down, and put
600 // the appropriate info table in the gap.
601 for (i = 0; i < arity; i++) {
602 Sp[(int)i-1] = Sp[i];
603 // ^^^^^ careful, i-1 might be negative, but i in unsigned
604 }
605 Sp[arity-1] = app_ptrs_itbl[n-arity-1];
606 Sp--;
607 goto run_BCO_fun;
608 }
609 else if (arity == n) {
610 goto run_BCO_fun;
611 }
612 else /* arity > n */ {
613 // build a PAP and return it.
614 StgPAP *pap;
615 nat i;
616 pap = (StgPAP *)allocate(PAP_sizeW(m));
617 SET_HDR(pap, &stg_PAP_info,CCCS);
618 pap->arity = arity - n;
619 pap->fun = obj;
620 pap->n_args = m;
621 for (i = 0; i < m; i++) {
622 pap->payload[i] = (StgClosure *)Sp[i];
623 }
624 obj = (StgClosure *)pap;
625 Sp += m;
626 goto do_return;
627 }
628 }
629
630 // No point in us applying machine-code functions
631 default:
632 defer_apply_to_sched:
633 Sp -= 2;
634 Sp[1] = (W_)obj;
635 Sp[0] = (W_)&stg_enter_info;
636 RETURN_TO_SCHEDULER_NO_PAUSE(ThreadRunGHC, ThreadYielding);
637 }
638
639 // ------------------------------------------------------------------------
640 // Ok, we now have a bco (obj), and its arguments are all on the
641 // stack. We can start executing the byte codes.
642 //
643 // The stack is in one of two states. First, if this BCO is a
644 // function:
645 //
646 // | .... |
647 // +---------------+
648 // | arg2 |
649 // +---------------+
650 // | arg1 |
651 // +---------------+
652 //
653 // Second, if this BCO is a continuation:
654 //
655 // | .... |
656 // +---------------+
657 // | fv2 |
658 // +---------------+
659 // | fv1 |
660 // +---------------+
661 // | BCO |
662 // +---------------+
663 // | stg_ctoi_ret_ |
664 // +---------------+
665 // | retval |
666 // +---------------+
667 //
668 // where retval is the value being returned to this continuation.
669 // In the event of a stack check, heap check, or context switch,
670 // we need to leave the stack in a sane state so the garbage
671 // collector can find all the pointers.
672 //
673 // (1) BCO is a function: the BCO's bitmap describes the
674 // pointerhood of the arguments.
675 //
676 // (2) BCO is a continuation: BCO's bitmap describes the
677 // pointerhood of the free variables.
678 //
679 // Sadly we have three different kinds of stack/heap/cswitch check
680 // to do:
681
682
683 run_BCO_return:
684 // Heap check
685 if (doYouWantToGC()) {
686 Sp--; Sp[0] = (W_)&stg_enter_info;
687 RETURN_TO_SCHEDULER(ThreadInterpret, HeapOverflow);
688 }
689 // Stack checks aren't necessary at return points, the stack use
690 // is aggregated into the enclosing function entry point.
691
692 goto run_BCO;
693
694 run_BCO_return_unboxed:
695 // Heap check
696 if (doYouWantToGC()) {
697 RETURN_TO_SCHEDULER(ThreadInterpret, HeapOverflow);
698 }
699 // Stack checks aren't necessary at return points, the stack use
700 // is aggregated into the enclosing function entry point.
701
702 goto run_BCO;
703
704 run_BCO_fun:
705 IF_DEBUG(sanity,
706 Sp -= 2;
707 Sp[1] = (W_)obj;
708 Sp[0] = (W_)&stg_apply_interp_info;
709 checkStackChunk(Sp,SpLim);
710 Sp += 2;
711 );
712
713 // Heap check
714 if (doYouWantToGC()) {
715 Sp -= 2;
716 Sp[1] = (W_)obj;
717 Sp[0] = (W_)&stg_apply_interp_info; // placeholder, really
718 RETURN_TO_SCHEDULER(ThreadInterpret, HeapOverflow);
719 }
720
721 // Stack check
722 if (Sp - INTERP_STACK_CHECK_THRESH < SpLim) {
723 Sp -= 2;
724 Sp[1] = (W_)obj;
725 Sp[0] = (W_)&stg_apply_interp_info; // placeholder, really
726 RETURN_TO_SCHEDULER(ThreadInterpret, StackOverflow);
727 }
728
729 goto run_BCO;
730
731 // Now, actually interpret the BCO... (no returning to the
732 // scheduler again until the stack is in an orderly state).
733 run_BCO:
734 INTERP_TICK(it_BCO_entries);
735 {
736 register int bciPtr = 1; /* instruction pointer */
737 register StgWord16 bci;
738 register StgBCO* bco = (StgBCO*)obj;
739 register StgWord16* instrs = (StgWord16*)(bco->instrs->payload);
740 register StgWord* literals = (StgWord*)(&bco->literals->payload[0]);
741 register StgPtr* ptrs = (StgPtr*)(&bco->ptrs->payload[0]);
742
743 #ifdef INTERP_STATS
744 it_lastopc = 0; /* no opcode */
745 #endif
746
747 nextInsn:
748 ASSERT(bciPtr <= instrs[0]);
749 IF_DEBUG(interpreter,
750 //if (do_print_stack) {
751 //debugBelch("\n-- BEGIN stack\n");
752 //printStack(Sp,cap->r.rCurrentTSO->stack+cap->r.rCurrentTSO->stack_size,iSu);
753 //debugBelch("-- END stack\n\n");
754 //}
755 debugBelch("Sp = %p pc = %d ", Sp, bciPtr);
756 disInstr(bco,bciPtr);
757 if (0) { int i;
758 debugBelch("\n");
759 for (i = 8; i >= 0; i--) {
760 debugBelch("%d %p\n", i, (StgPtr)(*(Sp+i)));
761 }
762 debugBelch("\n");
763 }
764 //if (do_print_stack) checkStack(Sp,cap->r.rCurrentTSO->stack+cap->r.rCurrentTSO->stack_size,iSu);
765 );
766
767
768 INTERP_TICK(it_insns);
769
770 #ifdef INTERP_STATS
771 ASSERT( (int)instrs[bciPtr] >= 0 && (int)instrs[bciPtr] < 27 );
772 it_ofreq[ (int)instrs[bciPtr] ] ++;
773 it_oofreq[ it_lastopc ][ (int)instrs[bciPtr] ] ++;
774 it_lastopc = (int)instrs[bciPtr];
775 #endif
776
777 bci = BCO_NEXT;
778 /* We use the high 8 bits for flags, only the highest of which is
779 * currently allocated */
780 ASSERT((bci & 0xFF00) == (bci & 0x8000));
781
782 switch (bci & 0xFF) {
783
784 /* check for a breakpoint on the beginning of a let binding */
785 case bci_BRK_FUN:
786 {
787 int arg1_brk_array, arg2_array_index, arg3_freeVars;
788 StgArrWords *breakPoints;
789 int returning_from_break; // are we resuming execution from a breakpoint?
790 // if yes, then don't break this time around
791 StgClosure *ioAction; // the io action to run at a breakpoint
792
793 StgAP_STACK *new_aps; // a closure to save the top stack frame on the heap
794 int i;
795 int size_words;
796
797 arg1_brk_array = BCO_NEXT; // 1st arg of break instruction
798 arg2_array_index = BCO_NEXT; // 2nd arg of break instruction
799 arg3_freeVars = BCO_NEXT; // 3rd arg of break instruction
800
801 // check if we are returning from a breakpoint - this info
802 // is stored in the flags field of the current TSO
803 returning_from_break = cap->r.rCurrentTSO->flags & TSO_STOPPED_ON_BREAKPOINT;
804
805 // if we are returning from a break then skip this section
806 // and continue executing
807 if (!returning_from_break)
808 {
809 breakPoints = (StgArrWords *) BCO_PTR(arg1_brk_array);
810
811 // stop the current thread if either the
812 // "stop_next_breakpoint" flag is true OR if the
813 // breakpoint flag for this particular expression is
814 // true
815 if (stop_next_breakpoint == rtsTrue ||
816 breakPoints->payload[arg2_array_index] == rtsTrue)
817 {
818 // make sure we don't automatically stop at the
819 // next breakpoint
820 stop_next_breakpoint = rtsFalse;
821
822 // allocate memory for a new AP_STACK, enough to
823 // store the top stack frame plus an
824 // stg_apply_interp_info pointer and a pointer to
825 // the BCO
826 size_words = BCO_BITMAP_SIZE(obj) + 2;
827 new_aps = (StgAP_STACK *) allocate (AP_STACK_sizeW(size_words));
828 SET_HDR(new_aps,&stg_AP_STACK_info,CCS_SYSTEM);
829 new_aps->size = size_words;
830 new_aps->fun = &stg_dummy_ret_closure;
831
832 // fill in the payload of the AP_STACK
833 new_aps->payload[0] = (StgClosure *)&stg_apply_interp_info;
834 new_aps->payload[1] = (StgClosure *)obj;
835
836 // copy the contents of the top stack frame into the AP_STACK
837 for (i = 2; i < size_words; i++)
838 {
839 new_aps->payload[i] = (StgClosure *)Sp[i-2];
840 }
841
842 // prepare the stack so that we can call the
843 // breakPointIOAction and ensure that the stack is
844 // in a reasonable state for the GC and so that
845 // execution of this BCO can continue when we resume
846 ioAction = (StgClosure *) deRefStablePtr (breakPointIOAction);
847 Sp -= 7;
848 Sp[6] = (W_)obj;
849 Sp[5] = (W_)&stg_apply_interp_info;
850 Sp[4] = (W_)new_aps; // the AP_STACK
851 Sp[3] = (W_)BCO_PTR(arg3_freeVars); // the info about local vars of the breakpoint
852 Sp[2] = (W_)&stg_ap_ppv_info;
853 Sp[1] = (W_)ioAction; // apply the IO action to its two arguments above
854 Sp[0] = (W_)&stg_enter_info; // get ready to run the IO action
855
856 // set the flag in the TSO to say that we are now
857 // stopping at a breakpoint so that when we resume
858 // we don't stop on the same breakpoint that we
859 // already stopped at just now
860 cap->r.rCurrentTSO->flags |= TSO_STOPPED_ON_BREAKPOINT;
861
862 // stop this thread and return to the scheduler -
863 // eventually we will come back and the IO action on
864 // the top of the stack will be executed
865 RETURN_TO_SCHEDULER_NO_PAUSE(ThreadRunGHC, ThreadYielding);
866 }
867 }
868 // record that this thread is not stopped at a breakpoint anymore
869 cap->r.rCurrentTSO->flags &= ~TSO_STOPPED_ON_BREAKPOINT;
870
871 // continue normal execution of the byte code instructions
872 goto nextInsn;
873 }
874
875 case bci_STKCHECK: {
876 // Explicit stack check at the beginning of a function
877 // *only* (stack checks in case alternatives are
878 // propagated to the enclosing function).
879 StgWord stk_words_reqd = BCO_GET_LARGE_ARG + 1;
880 if (Sp - stk_words_reqd < SpLim) {
881 Sp -= 2;
882 Sp[1] = (W_)obj;
883 Sp[0] = (W_)&stg_apply_interp_info;
884 RETURN_TO_SCHEDULER(ThreadInterpret, StackOverflow);
885 } else {
886 goto nextInsn;
887 }
888 }
889
890 case bci_PUSH_L: {
891 int o1 = BCO_NEXT;
892 Sp[-1] = Sp[o1];
893 Sp--;
894 goto nextInsn;
895 }
896
897 case bci_PUSH_LL: {
898 int o1 = BCO_NEXT;
899 int o2 = BCO_NEXT;
900 Sp[-1] = Sp[o1];
901 Sp[-2] = Sp[o2];
902 Sp -= 2;
903 goto nextInsn;
904 }
905
906 case bci_PUSH_LLL: {
907 int o1 = BCO_NEXT;
908 int o2 = BCO_NEXT;
909 int o3 = BCO_NEXT;
910 Sp[-1] = Sp[o1];
911 Sp[-2] = Sp[o2];
912 Sp[-3] = Sp[o3];
913 Sp -= 3;
914 goto nextInsn;
915 }
916
917 case bci_PUSH_G: {
918 int o1 = BCO_NEXT;
919 Sp[-1] = BCO_PTR(o1);
920 Sp -= 1;
921 goto nextInsn;
922 }
923
924 case bci_PUSH_ALTS: {
925 int o_bco = BCO_NEXT;
926 Sp[-2] = (W_)&stg_ctoi_R1p_info;
927 Sp[-1] = BCO_PTR(o_bco);
928 Sp -= 2;
929 goto nextInsn;
930 }
931
932 case bci_PUSH_ALTS_P: {
933 int o_bco = BCO_NEXT;
934 Sp[-2] = (W_)&stg_ctoi_R1unpt_info;
935 Sp[-1] = BCO_PTR(o_bco);
936 Sp -= 2;
937 goto nextInsn;
938 }
939
940 case bci_PUSH_ALTS_N: {
941 int o_bco = BCO_NEXT;
942 Sp[-2] = (W_)&stg_ctoi_R1n_info;
943 Sp[-1] = BCO_PTR(o_bco);
944 Sp -= 2;
945 goto nextInsn;
946 }
947
948 case bci_PUSH_ALTS_F: {
949 int o_bco = BCO_NEXT;
950 Sp[-2] = (W_)&stg_ctoi_F1_info;
951 Sp[-1] = BCO_PTR(o_bco);
952 Sp -= 2;
953 goto nextInsn;
954 }
955
956 case bci_PUSH_ALTS_D: {
957 int o_bco = BCO_NEXT;
958 Sp[-2] = (W_)&stg_ctoi_D1_info;
959 Sp[-1] = BCO_PTR(o_bco);
960 Sp -= 2;
961 goto nextInsn;
962 }
963
964 case bci_PUSH_ALTS_L: {
965 int o_bco = BCO_NEXT;
966 Sp[-2] = (W_)&stg_ctoi_L1_info;
967 Sp[-1] = BCO_PTR(o_bco);
968 Sp -= 2;
969 goto nextInsn;
970 }
971
972 case bci_PUSH_ALTS_V: {
973 int o_bco = BCO_NEXT;
974 Sp[-2] = (W_)&stg_ctoi_V_info;
975 Sp[-1] = BCO_PTR(o_bco);
976 Sp -= 2;
977 goto nextInsn;
978 }
979
980 case bci_PUSH_APPLY_N:
981 Sp--; Sp[0] = (W_)&stg_ap_n_info;
982 goto nextInsn;
983 case bci_PUSH_APPLY_V:
984 Sp--; Sp[0] = (W_)&stg_ap_v_info;
985 goto nextInsn;
986 case bci_PUSH_APPLY_F:
987 Sp--; Sp[0] = (W_)&stg_ap_f_info;
988 goto nextInsn;
989 case bci_PUSH_APPLY_D:
990 Sp--; Sp[0] = (W_)&stg_ap_d_info;
991 goto nextInsn;
992 case bci_PUSH_APPLY_L:
993 Sp--; Sp[0] = (W_)&stg_ap_l_info;
994 goto nextInsn;
995 case bci_PUSH_APPLY_P:
996 Sp--; Sp[0] = (W_)&stg_ap_p_info;
997 goto nextInsn;
998 case bci_PUSH_APPLY_PP:
999 Sp--; Sp[0] = (W_)&stg_ap_pp_info;
1000 goto nextInsn;
1001 case bci_PUSH_APPLY_PPP:
1002 Sp--; Sp[0] = (W_)&stg_ap_ppp_info;
1003 goto nextInsn;
1004 case bci_PUSH_APPLY_PPPP:
1005 Sp--; Sp[0] = (W_)&stg_ap_pppp_info;
1006 goto nextInsn;
1007 case bci_PUSH_APPLY_PPPPP:
1008 Sp--; Sp[0] = (W_)&stg_ap_ppppp_info;
1009 goto nextInsn;
1010 case bci_PUSH_APPLY_PPPPPP:
1011 Sp--; Sp[0] = (W_)&stg_ap_pppppp_info;
1012 goto nextInsn;
1013
1014 case bci_PUSH_UBX: {
1015 int i;
1016 int o_lits = BCO_NEXT;
1017 int n_words = BCO_NEXT;
1018 Sp -= n_words;
1019 for (i = 0; i < n_words; i++) {
1020 Sp[i] = (W_)BCO_LIT(o_lits+i);
1021 }
1022 goto nextInsn;
1023 }
1024
1025 case bci_SLIDE: {
1026 int n = BCO_NEXT;
1027 int by = BCO_NEXT;
1028 /* a_1, .. a_n, b_1, .. b_by, s => a_1, .. a_n, s */
1029 while(--n >= 0) {
1030 Sp[n+by] = Sp[n];
1031 }
1032 Sp += by;
1033 INTERP_TICK(it_slides);
1034 goto nextInsn;
1035 }
1036
1037 case bci_ALLOC_AP: {
1038 StgAP* ap;
1039 int n_payload = BCO_NEXT;
1040 ap = (StgAP*)allocate(AP_sizeW(n_payload));
1041 Sp[-1] = (W_)ap;
1042 ap->n_args = n_payload;
1043 SET_HDR(ap, &stg_AP_info, CCS_SYSTEM/*ToDo*/)
1044 Sp --;
1045 goto nextInsn;
1046 }
1047
1048 case bci_ALLOC_PAP: {
1049 StgPAP* pap;
1050 int arity = BCO_NEXT;
1051 int n_payload = BCO_NEXT;
1052 pap = (StgPAP*)allocate(PAP_sizeW(n_payload));
1053 Sp[-1] = (W_)pap;
1054 pap->n_args = n_payload;
1055 pap->arity = arity;
1056 SET_HDR(pap, &stg_PAP_info, CCS_SYSTEM/*ToDo*/)
1057 Sp --;
1058 goto nextInsn;
1059 }
1060
1061 case bci_MKAP: {
1062 int i;
1063 int stkoff = BCO_NEXT;
1064 int n_payload = BCO_NEXT;
1065 StgAP* ap = (StgAP*)Sp[stkoff];
1066 ASSERT((int)ap->n_args == n_payload);
1067 ap->fun = (StgClosure*)Sp[0];
1068
1069 // The function should be a BCO, and its bitmap should
1070 // cover the payload of the AP correctly.
1071 ASSERT(get_itbl(ap->fun)->type == BCO
1072 && BCO_BITMAP_SIZE(ap->fun) == ap->n_args);
1073
1074 for (i = 0; i < n_payload; i++)
1075 ap->payload[i] = (StgClosure*)Sp[i+1];
1076 Sp += n_payload+1;
1077 IF_DEBUG(interpreter,
1078 debugBelch("\tBuilt ");
1079 printObj((StgClosure*)ap);
1080 );
1081 goto nextInsn;
1082 }
1083
1084 case bci_MKPAP: {
1085 int i;
1086 int stkoff = BCO_NEXT;
1087 int n_payload = BCO_NEXT;
1088 StgPAP* pap = (StgPAP*)Sp[stkoff];
1089 ASSERT((int)pap->n_args == n_payload);
1090 pap->fun = (StgClosure*)Sp[0];
1091
1092 // The function should be a BCO
1093 ASSERT(get_itbl(pap->fun)->type == BCO);
1094
1095 for (i = 0; i < n_payload; i++)
1096 pap->payload[i] = (StgClosure*)Sp[i+1];
1097 Sp += n_payload+1;
1098 IF_DEBUG(interpreter,
1099 debugBelch("\tBuilt ");
1100 printObj((StgClosure*)pap);
1101 );
1102 goto nextInsn;
1103 }
1104
1105 case bci_UNPACK: {
1106 /* Unpack N ptr words from t.o.s constructor */
1107 int i;
1108 int n_words = BCO_NEXT;
1109 StgClosure* con = (StgClosure*)Sp[0];
1110 Sp -= n_words;
1111 for (i = 0; i < n_words; i++) {
1112 Sp[i] = (W_)con->payload[i];
1113 }
1114 goto nextInsn;
1115 }
1116
1117 case bci_PACK: {
1118 int i;
1119 int o_itbl = BCO_NEXT;
1120 int n_words = BCO_NEXT;
1121 StgInfoTable* itbl = INFO_PTR_TO_STRUCT(BCO_LIT(o_itbl));
1122 int request = CONSTR_sizeW( itbl->layout.payload.ptrs,
1123 itbl->layout.payload.nptrs );
1124 StgClosure* con = (StgClosure*)allocate_NONUPD(request);
1125 ASSERT( itbl->layout.payload.ptrs + itbl->layout.payload.nptrs > 0);
1126 SET_HDR(con, (StgInfoTable*)BCO_LIT(o_itbl), CCS_SYSTEM/*ToDo*/);
1127 for (i = 0; i < n_words; i++) {
1128 con->payload[i] = (StgClosure*)Sp[i];
1129 }
1130 Sp += n_words;
1131 Sp --;
1132 Sp[0] = (W_)con;
1133 IF_DEBUG(interpreter,
1134 debugBelch("\tBuilt ");
1135 printObj((StgClosure*)con);
1136 );
1137 goto nextInsn;
1138 }
1139
1140 case bci_TESTLT_P: {
1141 unsigned int discr = BCO_NEXT;
1142 int failto = BCO_NEXT;
1143 StgClosure* con = (StgClosure*)Sp[0];
1144 if (GET_TAG(con) >= discr) {
1145 bciPtr = failto;
1146 }
1147 goto nextInsn;
1148 }
1149
1150 case bci_TESTEQ_P: {
1151 unsigned int discr = BCO_NEXT;
1152 int failto = BCO_NEXT;
1153 StgClosure* con = (StgClosure*)Sp[0];
1154 if (GET_TAG(con) != discr) {
1155 bciPtr = failto;
1156 }
1157 goto nextInsn;
1158 }
1159
1160 case bci_TESTLT_I: {
1161 // There should be an Int at Sp[1], and an info table at Sp[0].
1162 int discr = BCO_NEXT;
1163 int failto = BCO_NEXT;
1164 I_ stackInt = (I_)Sp[1];
1165 if (stackInt >= (I_)BCO_LIT(discr))
1166 bciPtr = failto;
1167 goto nextInsn;
1168 }
1169
1170 case bci_TESTEQ_I: {
1171 // There should be an Int at Sp[1], and an info table at Sp[0].
1172 int discr = BCO_NEXT;
1173 int failto = BCO_NEXT;
1174 I_ stackInt = (I_)Sp[1];
1175 if (stackInt != (I_)BCO_LIT(discr)) {
1176 bciPtr = failto;
1177 }
1178 goto nextInsn;
1179 }
1180
1181 case bci_TESTLT_D: {
1182 // There should be a Double at Sp[1], and an info table at Sp[0].
1183 int discr = BCO_NEXT;
1184 int failto = BCO_NEXT;
1185 StgDouble stackDbl, discrDbl;
1186 stackDbl = PK_DBL( & Sp[1] );
1187 discrDbl = PK_DBL( & BCO_LIT(discr) );
1188 if (stackDbl >= discrDbl) {
1189 bciPtr = failto;
1190 }
1191 goto nextInsn;
1192 }
1193
1194 case bci_TESTEQ_D: {
1195 // There should be a Double at Sp[1], and an info table at Sp[0].
1196 int discr = BCO_NEXT;
1197 int failto = BCO_NEXT;
1198 StgDouble stackDbl, discrDbl;
1199 stackDbl = PK_DBL( & Sp[1] );
1200 discrDbl = PK_DBL( & BCO_LIT(discr) );
1201 if (stackDbl != discrDbl) {
1202 bciPtr = failto;
1203 }
1204 goto nextInsn;
1205 }
1206
1207 case bci_TESTLT_F: {
1208 // There should be a Float at Sp[1], and an info table at Sp[0].
1209 int discr = BCO_NEXT;
1210 int failto = BCO_NEXT;
1211 StgFloat stackFlt, discrFlt;
1212 stackFlt = PK_FLT( & Sp[1] );
1213 discrFlt = PK_FLT( & BCO_LIT(discr) );
1214 if (stackFlt >= discrFlt) {
1215 bciPtr = failto;
1216 }
1217 goto nextInsn;
1218 }
1219
1220 case bci_TESTEQ_F: {
1221 // There should be a Float at Sp[1], and an info table at Sp[0].
1222 int discr = BCO_NEXT;
1223 int failto = BCO_NEXT;
1224 StgFloat stackFlt, discrFlt;
1225 stackFlt = PK_FLT( & Sp[1] );
1226 discrFlt = PK_FLT( & BCO_LIT(discr) );
1227 if (stackFlt != discrFlt) {
1228 bciPtr = failto;
1229 }
1230 goto nextInsn;
1231 }
1232
1233 // Control-flow ish things
1234 case bci_ENTER:
1235 // Context-switch check. We put it here to ensure that
1236 // the interpreter has done at least *some* work before
1237 // context switching: sometimes the scheduler can invoke
1238 // the interpreter with context_switch == 1, particularly
1239 // if the -C0 flag has been given on the cmd line.
1240 if (context_switch) {
1241 Sp--; Sp[0] = (W_)&stg_enter_info;
1242 RETURN_TO_SCHEDULER(ThreadInterpret, ThreadYielding);
1243 }
1244 goto eval;
1245
1246 case bci_RETURN:
1247 obj = (StgClosure *)Sp[0];
1248 Sp++;
1249 goto do_return;
1250
1251 case bci_RETURN_P:
1252 Sp--;
1253 Sp[0] = (W_)&stg_gc_unpt_r1_info;
1254 goto do_return_unboxed;
1255 case bci_RETURN_N:
1256 Sp--;
1257 Sp[0] = (W_)&stg_gc_unbx_r1_info;
1258 goto do_return_unboxed;
1259 case bci_RETURN_F:
1260 Sp--;
1261 Sp[0] = (W_)&stg_gc_f1_info;
1262 goto do_return_unboxed;
1263 case bci_RETURN_D:
1264 Sp--;
1265 Sp[0] = (W_)&stg_gc_d1_info;
1266 goto do_return_unboxed;
1267 case bci_RETURN_L:
1268 Sp--;
1269 Sp[0] = (W_)&stg_gc_l1_info;
1270 goto do_return_unboxed;
1271 case bci_RETURN_V:
1272 Sp--;
1273 Sp[0] = (W_)&stg_gc_void_info;
1274 goto do_return_unboxed;
1275
1276 case bci_SWIZZLE: {
1277 int stkoff = BCO_NEXT;
1278 signed short n = (signed short)(BCO_NEXT);
1279 Sp[stkoff] += (W_)n;
1280 goto nextInsn;
1281 }
1282
1283 case bci_CCALL: {
1284 void *tok;
1285 int stk_offset = BCO_NEXT;
1286 int o_itbl = BCO_NEXT;
1287 void(*marshall_fn)(void*) = (void (*)(void*))BCO_LIT(o_itbl);
1288 int ret_dyn_size =
1289 RET_DYN_BITMAP_SIZE + RET_DYN_NONPTR_REGS_SIZE
1290 + sizeofW(StgRetDyn);
1291
1292 #ifdef THREADED_RTS
1293 // Threaded RTS:
1294 // Arguments on the TSO stack are not good, because garbage
1295 // collection might move the TSO as soon as we call
1296 // suspendThread below.
1297
1298 W_ arguments[stk_offset];
1299
1300 memcpy(arguments, Sp, sizeof(W_) * stk_offset);
1301 #endif
1302
1303 // Restore the Haskell thread's current value of errno
1304 errno = cap->r.rCurrentTSO->saved_errno;
1305
1306 // There are a bunch of non-ptr words on the stack (the
1307 // ccall args, the ccall fun address and space for the
1308 // result), which we need to cover with an info table
1309 // since we might GC during this call.
1310 //
1311 // We know how many (non-ptr) words there are before the
1312 // next valid stack frame: it is the stk_offset arg to the
1313 // CCALL instruction. So we build a RET_DYN stack frame
1314 // on the stack frame to describe this chunk of stack.
1315 //
1316 Sp -= ret_dyn_size;
1317 ((StgRetDyn *)Sp)->liveness = NO_PTRS | N_NONPTRS(stk_offset);
1318 ((StgRetDyn *)Sp)->info = (StgInfoTable *)&stg_gc_gen_info;
1319
1320 SAVE_STACK_POINTERS;
1321 tok = suspendThread(&cap->r);
1322
1323 #ifndef THREADED_RTS
1324 // Careful:
1325 // suspendThread might have shifted the stack
1326 // around (stack squeezing), so we have to grab the real
1327 // Sp out of the TSO to find the ccall args again.
1328
1329 marshall_fn ( (void*)(cap->r.rCurrentTSO->sp + ret_dyn_size) );
1330 #else
1331 // Threaded RTS:
1332 // We already made a copy of the arguments above.
1333
1334 marshall_fn ( arguments );
1335 #endif
1336
1337 // And restart the thread again, popping the RET_DYN frame.
1338 cap = (Capability *)((void *)((unsigned char*)resumeThread(tok) - sizeof(StgFunTable)));
1339 LOAD_STACK_POINTERS;
1340 Sp += ret_dyn_size;
1341
1342 // Save the Haskell thread's current value of errno
1343 cap->r.rCurrentTSO->saved_errno = errno;
1344
1345 #ifdef THREADED_RTS
1346 // Threaded RTS:
1347 // Copy the "arguments", which might include a return value,
1348 // back to the TSO stack. It would of course be enough to
1349 // just copy the return value, but we don't know the offset.
1350 memcpy(Sp, arguments, sizeof(W_) * stk_offset);
1351 #endif
1352
1353 goto nextInsn;
1354 }
1355
1356 case bci_JMP: {
1357 /* BCO_NEXT modifies bciPtr, so be conservative. */
1358 int nextpc = BCO_NEXT;
1359 bciPtr = nextpc;
1360 goto nextInsn;
1361 }
1362
1363 case bci_CASEFAIL:
1364 barf("interpretBCO: hit a CASEFAIL");
1365
1366 // Errors
1367 default:
1368 barf("interpretBCO: unknown or unimplemented opcode %d",
1369 (int)BCO_NEXT);
1370
1371 } /* switch on opcode */
1372 }
1373 }
1374
1375 barf("interpretBCO: fell off end of the interpreter");
1376 }
1377
1378 /* set the single step flag for the debugger to True -
1379 it gets set back to false in the interpreter everytime
1380 we hit a breakpoint
1381 */
1382 void rts_setStepFlag (void);
1383 void rts_setStepFlag (void)
1384 {
1385 stop_next_breakpoint = rtsTrue;
1386 }