Re-working of the breakpoint support
[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; /* first argument of break instruction */
798 arg2_array_index = BCO_NEXT; /* second dargument of break instruction */
799 arg3_freeVars = BCO_NEXT; /* third argument of break instruction */
800
801 // check if we are returning from a breakpoint - this info is stored in
802 // 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 and continue executing
806 if (!returning_from_break)
807 {
808 breakPoints = (StgArrWords *) BCO_PTR(arg1_brk_array);
809
810 // stop the current thread if either the "stop_next_breakpoint" flag is true
811 // OR if the breakpoint flag for this particular expression is true
812 if (stop_next_breakpoint == rtsTrue || breakPoints->payload[arg2_array_index] == rtsTrue)
813 {
814 stop_next_breakpoint = rtsFalse; // make sure we don't automatically stop at the next breakpoint
815
816 // allocate memory for a new AP_STACK, enough to store the top stack frame
817 // plus an stg_apply_interp_info pointer and a pointer to the BCO
818 size_words = BCO_BITMAP_SIZE(obj) + 2;
819 new_aps = (StgAP_STACK *) allocate (AP_STACK_sizeW(size_words));
820 SET_HDR(new_aps,&stg_AP_STACK_info,CCS_SYSTEM);
821 new_aps->size = size_words;
822 // we should never enter new_aps->fun, so it is assigned to a dummy value
823 // ToDo: fixme to something that explodes with an error if you enter it
824 new_aps->fun = &stg_dummy_ret_closure;
825
826 // fill in the payload of the AP_STACK
827 new_aps->payload[0] = (W_)&stg_apply_interp_info;
828 new_aps->payload[1] = (W_)obj;
829
830 // copy the contents of the top stack frame into the AP_STACK
831 for (i = 2; i < size_words; i++)
832 {
833 new_aps->payload[i] = (W_)Sp[i-2];
834 }
835
836 // prepare the stack so that we can call the breakPointIOAction
837 // and ensure that the stack is in a reasonable state for the GC
838 // and so that execution of this BCO can continue when we resume
839 ioAction = (StgClosure *) deRefStablePtr (breakPointIOAction);
840 Sp -= 7;
841 Sp[6] = (W_)obj;
842 Sp[5] = (W_)&stg_apply_interp_info;
843 Sp[4] = (W_)new_aps; /* the AP_STACK */
844 Sp[3] = (W_)BCO_PTR(arg3_freeVars); /* the info about local vars of the breakpoint */
845 Sp[2] = (W_)&stg_ap_ppv_info;
846 Sp[1] = (W_)ioAction; /* apply the IO action to its two arguments above */
847 Sp[0] = (W_)&stg_enter_info; /* get ready to run the IO action */
848
849 // set the flag in the TSO to say that we are now stopping at a breakpoint
850 // so that when we resume we don't stop on the same breakpoint that we already
851 // stopped at just now
852 cap->r.rCurrentTSO->flags |= TSO_STOPPED_ON_BREAKPOINT;
853
854 // stop this thread and return to the scheduler - eventually we will come back
855 // and the IO action on the top of the stack will be executed
856 RETURN_TO_SCHEDULER_NO_PAUSE(ThreadRunGHC, ThreadYielding);
857 }
858 }
859 // record that this thread is not stopped at a breakpoint anymore
860 cap->r.rCurrentTSO->flags &= ~TSO_STOPPED_ON_BREAKPOINT;
861
862 // continue normal execution of the byte code instructions
863 goto nextInsn;
864 }
865
866 case bci_STKCHECK: {
867 // Explicit stack check at the beginning of a function
868 // *only* (stack checks in case alternatives are
869 // propagated to the enclosing function).
870 StgWord stk_words_reqd = BCO_GET_LARGE_ARG + 1;
871 if (Sp - stk_words_reqd < SpLim) {
872 Sp -= 2;
873 Sp[1] = (W_)obj;
874 Sp[0] = (W_)&stg_apply_interp_info;
875 RETURN_TO_SCHEDULER(ThreadInterpret, StackOverflow);
876 } else {
877 goto nextInsn;
878 }
879 }
880
881 case bci_PUSH_L: {
882 int o1 = BCO_NEXT;
883 Sp[-1] = Sp[o1];
884 Sp--;
885 goto nextInsn;
886 }
887
888 case bci_PUSH_LL: {
889 int o1 = BCO_NEXT;
890 int o2 = BCO_NEXT;
891 Sp[-1] = Sp[o1];
892 Sp[-2] = Sp[o2];
893 Sp -= 2;
894 goto nextInsn;
895 }
896
897 case bci_PUSH_LLL: {
898 int o1 = BCO_NEXT;
899 int o2 = BCO_NEXT;
900 int o3 = BCO_NEXT;
901 Sp[-1] = Sp[o1];
902 Sp[-2] = Sp[o2];
903 Sp[-3] = Sp[o3];
904 Sp -= 3;
905 goto nextInsn;
906 }
907
908 case bci_PUSH_G: {
909 int o1 = BCO_NEXT;
910 Sp[-1] = BCO_PTR(o1);
911 Sp -= 1;
912 goto nextInsn;
913 }
914
915 case bci_PUSH_ALTS: {
916 int o_bco = BCO_NEXT;
917 Sp[-2] = (W_)&stg_ctoi_R1p_info;
918 Sp[-1] = BCO_PTR(o_bco);
919 Sp -= 2;
920 goto nextInsn;
921 }
922
923 case bci_PUSH_ALTS_P: {
924 int o_bco = BCO_NEXT;
925 Sp[-2] = (W_)&stg_ctoi_R1unpt_info;
926 Sp[-1] = BCO_PTR(o_bco);
927 Sp -= 2;
928 goto nextInsn;
929 }
930
931 case bci_PUSH_ALTS_N: {
932 int o_bco = BCO_NEXT;
933 Sp[-2] = (W_)&stg_ctoi_R1n_info;
934 Sp[-1] = BCO_PTR(o_bco);
935 Sp -= 2;
936 goto nextInsn;
937 }
938
939 case bci_PUSH_ALTS_F: {
940 int o_bco = BCO_NEXT;
941 Sp[-2] = (W_)&stg_ctoi_F1_info;
942 Sp[-1] = BCO_PTR(o_bco);
943 Sp -= 2;
944 goto nextInsn;
945 }
946
947 case bci_PUSH_ALTS_D: {
948 int o_bco = BCO_NEXT;
949 Sp[-2] = (W_)&stg_ctoi_D1_info;
950 Sp[-1] = BCO_PTR(o_bco);
951 Sp -= 2;
952 goto nextInsn;
953 }
954
955 case bci_PUSH_ALTS_L: {
956 int o_bco = BCO_NEXT;
957 Sp[-2] = (W_)&stg_ctoi_L1_info;
958 Sp[-1] = BCO_PTR(o_bco);
959 Sp -= 2;
960 goto nextInsn;
961 }
962
963 case bci_PUSH_ALTS_V: {
964 int o_bco = BCO_NEXT;
965 Sp[-2] = (W_)&stg_ctoi_V_info;
966 Sp[-1] = BCO_PTR(o_bco);
967 Sp -= 2;
968 goto nextInsn;
969 }
970
971 case bci_PUSH_APPLY_N:
972 Sp--; Sp[0] = (W_)&stg_ap_n_info;
973 goto nextInsn;
974 case bci_PUSH_APPLY_V:
975 Sp--; Sp[0] = (W_)&stg_ap_v_info;
976 goto nextInsn;
977 case bci_PUSH_APPLY_F:
978 Sp--; Sp[0] = (W_)&stg_ap_f_info;
979 goto nextInsn;
980 case bci_PUSH_APPLY_D:
981 Sp--; Sp[0] = (W_)&stg_ap_d_info;
982 goto nextInsn;
983 case bci_PUSH_APPLY_L:
984 Sp--; Sp[0] = (W_)&stg_ap_l_info;
985 goto nextInsn;
986 case bci_PUSH_APPLY_P:
987 Sp--; Sp[0] = (W_)&stg_ap_p_info;
988 goto nextInsn;
989 case bci_PUSH_APPLY_PP:
990 Sp--; Sp[0] = (W_)&stg_ap_pp_info;
991 goto nextInsn;
992 case bci_PUSH_APPLY_PPP:
993 Sp--; Sp[0] = (W_)&stg_ap_ppp_info;
994 goto nextInsn;
995 case bci_PUSH_APPLY_PPPP:
996 Sp--; Sp[0] = (W_)&stg_ap_pppp_info;
997 goto nextInsn;
998 case bci_PUSH_APPLY_PPPPP:
999 Sp--; Sp[0] = (W_)&stg_ap_ppppp_info;
1000 goto nextInsn;
1001 case bci_PUSH_APPLY_PPPPPP:
1002 Sp--; Sp[0] = (W_)&stg_ap_pppppp_info;
1003 goto nextInsn;
1004
1005 case bci_PUSH_UBX: {
1006 int i;
1007 int o_lits = BCO_NEXT;
1008 int n_words = BCO_NEXT;
1009 Sp -= n_words;
1010 for (i = 0; i < n_words; i++) {
1011 Sp[i] = (W_)BCO_LIT(o_lits+i);
1012 }
1013 goto nextInsn;
1014 }
1015
1016 case bci_SLIDE: {
1017 int n = BCO_NEXT;
1018 int by = BCO_NEXT;
1019 /* a_1, .. a_n, b_1, .. b_by, s => a_1, .. a_n, s */
1020 while(--n >= 0) {
1021 Sp[n+by] = Sp[n];
1022 }
1023 Sp += by;
1024 INTERP_TICK(it_slides);
1025 goto nextInsn;
1026 }
1027
1028 case bci_ALLOC_AP: {
1029 StgAP* ap;
1030 int n_payload = BCO_NEXT;
1031 ap = (StgAP*)allocate(AP_sizeW(n_payload));
1032 Sp[-1] = (W_)ap;
1033 ap->n_args = n_payload;
1034 SET_HDR(ap, &stg_AP_info, CCS_SYSTEM/*ToDo*/)
1035 Sp --;
1036 goto nextInsn;
1037 }
1038
1039 case bci_ALLOC_PAP: {
1040 StgPAP* pap;
1041 int arity = BCO_NEXT;
1042 int n_payload = BCO_NEXT;
1043 pap = (StgPAP*)allocate(PAP_sizeW(n_payload));
1044 Sp[-1] = (W_)pap;
1045 pap->n_args = n_payload;
1046 pap->arity = arity;
1047 SET_HDR(pap, &stg_PAP_info, CCS_SYSTEM/*ToDo*/)
1048 Sp --;
1049 goto nextInsn;
1050 }
1051
1052 case bci_MKAP: {
1053 int i;
1054 int stkoff = BCO_NEXT;
1055 int n_payload = BCO_NEXT;
1056 StgAP* ap = (StgAP*)Sp[stkoff];
1057 ASSERT((int)ap->n_args == n_payload);
1058 ap->fun = (StgClosure*)Sp[0];
1059
1060 // The function should be a BCO, and its bitmap should
1061 // cover the payload of the AP correctly.
1062 ASSERT(get_itbl(ap->fun)->type == BCO
1063 && BCO_BITMAP_SIZE(ap->fun) == ap->n_args);
1064
1065 for (i = 0; i < n_payload; i++)
1066 ap->payload[i] = (StgClosure*)Sp[i+1];
1067 Sp += n_payload+1;
1068 IF_DEBUG(interpreter,
1069 debugBelch("\tBuilt ");
1070 printObj((StgClosure*)ap);
1071 );
1072 goto nextInsn;
1073 }
1074
1075 case bci_MKPAP: {
1076 int i;
1077 int stkoff = BCO_NEXT;
1078 int n_payload = BCO_NEXT;
1079 StgPAP* pap = (StgPAP*)Sp[stkoff];
1080 ASSERT((int)pap->n_args == n_payload);
1081 pap->fun = (StgClosure*)Sp[0];
1082
1083 // The function should be a BCO
1084 ASSERT(get_itbl(pap->fun)->type == BCO);
1085
1086 for (i = 0; i < n_payload; i++)
1087 pap->payload[i] = (StgClosure*)Sp[i+1];
1088 Sp += n_payload+1;
1089 IF_DEBUG(interpreter,
1090 debugBelch("\tBuilt ");
1091 printObj((StgClosure*)pap);
1092 );
1093 goto nextInsn;
1094 }
1095
1096 case bci_UNPACK: {
1097 /* Unpack N ptr words from t.o.s constructor */
1098 int i;
1099 int n_words = BCO_NEXT;
1100 StgClosure* con = (StgClosure*)Sp[0];
1101 Sp -= n_words;
1102 for (i = 0; i < n_words; i++) {
1103 Sp[i] = (W_)con->payload[i];
1104 }
1105 goto nextInsn;
1106 }
1107
1108 case bci_PACK: {
1109 int i;
1110 int o_itbl = BCO_NEXT;
1111 int n_words = BCO_NEXT;
1112 StgInfoTable* itbl = INFO_PTR_TO_STRUCT(BCO_LIT(o_itbl));
1113 int request = CONSTR_sizeW( itbl->layout.payload.ptrs,
1114 itbl->layout.payload.nptrs );
1115 StgClosure* con = (StgClosure*)allocate_NONUPD(request);
1116 ASSERT( itbl->layout.payload.ptrs + itbl->layout.payload.nptrs > 0);
1117 SET_HDR(con, (StgInfoTable*)BCO_LIT(o_itbl), CCS_SYSTEM/*ToDo*/);
1118 for (i = 0; i < n_words; i++) {
1119 con->payload[i] = (StgClosure*)Sp[i];
1120 }
1121 Sp += n_words;
1122 Sp --;
1123 Sp[0] = (W_)con;
1124 IF_DEBUG(interpreter,
1125 debugBelch("\tBuilt ");
1126 printObj((StgClosure*)con);
1127 );
1128 goto nextInsn;
1129 }
1130
1131 case bci_TESTLT_P: {
1132 unsigned int discr = BCO_NEXT;
1133 int failto = BCO_NEXT;
1134 StgClosure* con = (StgClosure*)Sp[0];
1135 if (GET_TAG(con) >= discr) {
1136 bciPtr = failto;
1137 }
1138 goto nextInsn;
1139 }
1140
1141 case bci_TESTEQ_P: {
1142 unsigned int discr = BCO_NEXT;
1143 int failto = BCO_NEXT;
1144 StgClosure* con = (StgClosure*)Sp[0];
1145 if (GET_TAG(con) != discr) {
1146 bciPtr = failto;
1147 }
1148 goto nextInsn;
1149 }
1150
1151 case bci_TESTLT_I: {
1152 // There should be an Int at Sp[1], and an info table at Sp[0].
1153 int discr = BCO_NEXT;
1154 int failto = BCO_NEXT;
1155 I_ stackInt = (I_)Sp[1];
1156 if (stackInt >= (I_)BCO_LIT(discr))
1157 bciPtr = failto;
1158 goto nextInsn;
1159 }
1160
1161 case bci_TESTEQ_I: {
1162 // There should be an Int at Sp[1], and an info table at Sp[0].
1163 int discr = BCO_NEXT;
1164 int failto = BCO_NEXT;
1165 I_ stackInt = (I_)Sp[1];
1166 if (stackInt != (I_)BCO_LIT(discr)) {
1167 bciPtr = failto;
1168 }
1169 goto nextInsn;
1170 }
1171
1172 case bci_TESTLT_D: {
1173 // There should be a Double at Sp[1], and an info table at Sp[0].
1174 int discr = BCO_NEXT;
1175 int failto = BCO_NEXT;
1176 StgDouble stackDbl, discrDbl;
1177 stackDbl = PK_DBL( & Sp[1] );
1178 discrDbl = PK_DBL( & BCO_LIT(discr) );
1179 if (stackDbl >= discrDbl) {
1180 bciPtr = failto;
1181 }
1182 goto nextInsn;
1183 }
1184
1185 case bci_TESTEQ_D: {
1186 // There should be a Double at Sp[1], and an info table at Sp[0].
1187 int discr = BCO_NEXT;
1188 int failto = BCO_NEXT;
1189 StgDouble stackDbl, discrDbl;
1190 stackDbl = PK_DBL( & Sp[1] );
1191 discrDbl = PK_DBL( & BCO_LIT(discr) );
1192 if (stackDbl != discrDbl) {
1193 bciPtr = failto;
1194 }
1195 goto nextInsn;
1196 }
1197
1198 case bci_TESTLT_F: {
1199 // There should be a Float at Sp[1], and an info table at Sp[0].
1200 int discr = BCO_NEXT;
1201 int failto = BCO_NEXT;
1202 StgFloat stackFlt, discrFlt;
1203 stackFlt = PK_FLT( & Sp[1] );
1204 discrFlt = PK_FLT( & BCO_LIT(discr) );
1205 if (stackFlt >= discrFlt) {
1206 bciPtr = failto;
1207 }
1208 goto nextInsn;
1209 }
1210
1211 case bci_TESTEQ_F: {
1212 // There should be a Float at Sp[1], and an info table at Sp[0].
1213 int discr = BCO_NEXT;
1214 int failto = BCO_NEXT;
1215 StgFloat stackFlt, discrFlt;
1216 stackFlt = PK_FLT( & Sp[1] );
1217 discrFlt = PK_FLT( & BCO_LIT(discr) );
1218 if (stackFlt != discrFlt) {
1219 bciPtr = failto;
1220 }
1221 goto nextInsn;
1222 }
1223
1224 // Control-flow ish things
1225 case bci_ENTER:
1226 // Context-switch check. We put it here to ensure that
1227 // the interpreter has done at least *some* work before
1228 // context switching: sometimes the scheduler can invoke
1229 // the interpreter with context_switch == 1, particularly
1230 // if the -C0 flag has been given on the cmd line.
1231 if (context_switch) {
1232 Sp--; Sp[0] = (W_)&stg_enter_info;
1233 RETURN_TO_SCHEDULER(ThreadInterpret, ThreadYielding);
1234 }
1235 goto eval;
1236
1237 case bci_RETURN:
1238 obj = (StgClosure *)Sp[0];
1239 Sp++;
1240 goto do_return;
1241
1242 case bci_RETURN_P:
1243 Sp--;
1244 Sp[0] = (W_)&stg_gc_unpt_r1_info;
1245 goto do_return_unboxed;
1246 case bci_RETURN_N:
1247 Sp--;
1248 Sp[0] = (W_)&stg_gc_unbx_r1_info;
1249 goto do_return_unboxed;
1250 case bci_RETURN_F:
1251 Sp--;
1252 Sp[0] = (W_)&stg_gc_f1_info;
1253 goto do_return_unboxed;
1254 case bci_RETURN_D:
1255 Sp--;
1256 Sp[0] = (W_)&stg_gc_d1_info;
1257 goto do_return_unboxed;
1258 case bci_RETURN_L:
1259 Sp--;
1260 Sp[0] = (W_)&stg_gc_l1_info;
1261 goto do_return_unboxed;
1262 case bci_RETURN_V:
1263 Sp--;
1264 Sp[0] = (W_)&stg_gc_void_info;
1265 goto do_return_unboxed;
1266
1267 case bci_SWIZZLE: {
1268 int stkoff = BCO_NEXT;
1269 signed short n = (signed short)(BCO_NEXT);
1270 Sp[stkoff] += (W_)n;
1271 goto nextInsn;
1272 }
1273
1274 case bci_CCALL: {
1275 void *tok;
1276 int stk_offset = BCO_NEXT;
1277 int o_itbl = BCO_NEXT;
1278 void(*marshall_fn)(void*) = (void (*)(void*))BCO_LIT(o_itbl);
1279 int ret_dyn_size =
1280 RET_DYN_BITMAP_SIZE + RET_DYN_NONPTR_REGS_SIZE
1281 + sizeofW(StgRetDyn);
1282
1283 #ifdef THREADED_RTS
1284 // Threaded RTS:
1285 // Arguments on the TSO stack are not good, because garbage
1286 // collection might move the TSO as soon as we call
1287 // suspendThread below.
1288
1289 W_ arguments[stk_offset];
1290
1291 memcpy(arguments, Sp, sizeof(W_) * stk_offset);
1292 #endif
1293
1294 // Restore the Haskell thread's current value of errno
1295 errno = cap->r.rCurrentTSO->saved_errno;
1296
1297 // There are a bunch of non-ptr words on the stack (the
1298 // ccall args, the ccall fun address and space for the
1299 // result), which we need to cover with an info table
1300 // since we might GC during this call.
1301 //
1302 // We know how many (non-ptr) words there are before the
1303 // next valid stack frame: it is the stk_offset arg to the
1304 // CCALL instruction. So we build a RET_DYN stack frame
1305 // on the stack frame to describe this chunk of stack.
1306 //
1307 Sp -= ret_dyn_size;
1308 ((StgRetDyn *)Sp)->liveness = NO_PTRS | N_NONPTRS(stk_offset);
1309 ((StgRetDyn *)Sp)->info = (StgInfoTable *)&stg_gc_gen_info;
1310
1311 SAVE_STACK_POINTERS;
1312 tok = suspendThread(&cap->r);
1313
1314 #ifndef THREADED_RTS
1315 // Careful:
1316 // suspendThread might have shifted the stack
1317 // around (stack squeezing), so we have to grab the real
1318 // Sp out of the TSO to find the ccall args again.
1319
1320 marshall_fn ( (void*)(cap->r.rCurrentTSO->sp + ret_dyn_size) );
1321 #else
1322 // Threaded RTS:
1323 // We already made a copy of the arguments above.
1324
1325 marshall_fn ( arguments );
1326 #endif
1327
1328 // And restart the thread again, popping the RET_DYN frame.
1329 cap = (Capability *)((void *)((unsigned char*)resumeThread(tok) - sizeof(StgFunTable)));
1330 LOAD_STACK_POINTERS;
1331 Sp += ret_dyn_size;
1332
1333 // Save the Haskell thread's current value of errno
1334 cap->r.rCurrentTSO->saved_errno = errno;
1335
1336 #ifdef THREADED_RTS
1337 // Threaded RTS:
1338 // Copy the "arguments", which might include a return value,
1339 // back to the TSO stack. It would of course be enough to
1340 // just copy the return value, but we don't know the offset.
1341 memcpy(Sp, arguments, sizeof(W_) * stk_offset);
1342 #endif
1343
1344 goto nextInsn;
1345 }
1346
1347 case bci_JMP: {
1348 /* BCO_NEXT modifies bciPtr, so be conservative. */
1349 int nextpc = BCO_NEXT;
1350 bciPtr = nextpc;
1351 goto nextInsn;
1352 }
1353
1354 case bci_CASEFAIL:
1355 barf("interpretBCO: hit a CASEFAIL");
1356
1357 // Errors
1358 default:
1359 barf("interpretBCO: unknown or unimplemented opcode %d",
1360 (int)BCO_NEXT);
1361
1362 } /* switch on opcode */
1363 }
1364 }
1365
1366 barf("interpretBCO: fell off end of the interpreter");
1367 }
1368
1369 /* temporary code for peeking inside a AP_STACK and pulling out values
1370 based on their stack offset - used in the debugger for inspecting
1371 the local values of a breakpoint
1372 */
1373 HsStablePtr rts_getApStackVal (HsStablePtr, int);
1374 HsStablePtr rts_getApStackVal (HsStablePtr apStackSptr, int offset)
1375 {
1376 HsStablePtr resultSptr;
1377 StgAP_STACK *apStack;
1378 StgClosure **payload;
1379 StgClosure *val;
1380
1381 apStack = (StgAP_STACK *) deRefStablePtr (apStackSptr);
1382 payload = apStack->payload;
1383 val = (StgClosure *) payload[offset+2];
1384 resultSptr = getStablePtr (val);
1385 return resultSptr;
1386 }
1387
1388 /* set the single step flag for the debugger to True -
1389 it gets set back to false in the interpreter everytime
1390 we hit a breakpoint
1391 */
1392 void rts_setStepFlag (void);
1393 void rts_setStepFlag (void)
1394 {
1395 stop_next_breakpoint = rtsTrue;
1396 }