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