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