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