1 /* -----------------------------------------------------------------------------
4 * Copyright (c) The GHC Team, 1994-2002.
5 * ---------------------------------------------------------------------------*/
7 #include "PosixSource.h"
15 #include "LdvProfile.h"
21 #include "Bytecodes.h"
23 #include "Disassembler.h"
24 #include "Interpreter.h"
26 #include <string.h> /* for memcpy */
32 /* --------------------------------------------------------------------------
33 * The bytecode interpreter
34 * ------------------------------------------------------------------------*/
36 /* Gather stats about entry, opcode, opcode-pair frequencies. For
37 tuning the interpreter. */
39 /* #define INTERP_STATS */
42 /* Sp points to the lowest live word on the stack. */
44 #define BCO_NEXT instrs[bciPtr++]
45 #define BCO_NEXT_32 (bciPtr += 2, (((StgWord) instrs[bciPtr-2]) << 16) + ((StgWord) instrs[bciPtr-1]))
46 #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]))
47 #if WORD_SIZE_IN_BITS == 32
48 #define BCO_NEXT_WORD BCO_NEXT_32
49 #elif WORD_SIZE_IN_BITS == 64
50 #define BCO_NEXT_WORD BCO_NEXT_64
52 #error Cannot cope with WORD_SIZE_IN_BITS being nether 32 nor 64
54 #define BCO_GET_LARGE_ARG ((bci & bci_FLAG_LARGE_ARGS) ? BCO_NEXT_WORD : BCO_NEXT)
56 #define BCO_PTR(n) (W_)ptrs[n]
57 #define BCO_LIT(n) literals[n]
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;
64 #define SAVE_STACK_POINTERS \
65 cap->r.rCurrentTSO->sp = Sp
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); \
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); \
82 allocate_NONUPD (int n_words)
84 return allocate(stg_max(sizeofW(StgHeader)+MIN_PAYLOAD_SIZE, n_words));
87 int rts_stop_next_breakpoint = 0;
88 int rts_stop_on_exception = 0;
92 /* Hacky stats, for tuning the interpreter ... */
93 int it_unknown_entries[N_CLOSURE_TYPES];
94 int it_total_unknown_entries;
106 int it_oofreq[27][27];
110 #define INTERP_TICK(n) (n)++
112 void interp_startup ( void )
115 it_retto_BCO = it_retto_UPDATE = it_retto_other = 0;
116 it_total_entries = it_total_unknown_entries = 0;
117 for (i = 0; i < N_CLOSURE_TYPES; i++)
118 it_unknown_entries[i] = 0;
119 it_slides = it_insns = it_BCO_entries = 0;
120 for (i = 0; i < 27; i++) it_ofreq[i] = 0;
121 for (i = 0; i < 27; i++)
122 for (j = 0; j < 27; j++)
127 void interp_shutdown ( void )
129 int i, j, k, o_max, i_max, j_max;
130 debugBelch("%d constrs entered -> (%d BCO, %d UPD, %d ??? )\n",
131 it_retto_BCO + it_retto_UPDATE + it_retto_other,
132 it_retto_BCO, it_retto_UPDATE, it_retto_other );
133 debugBelch("%d total entries, %d unknown entries \n",
134 it_total_entries, it_total_unknown_entries);
135 for (i = 0; i < N_CLOSURE_TYPES; i++) {
136 if (it_unknown_entries[i] == 0) continue;
137 debugBelch(" type %2d: unknown entries (%4.1f%%) == %d\n",
138 i, 100.0 * ((double)it_unknown_entries[i]) /
139 ((double)it_total_unknown_entries),
140 it_unknown_entries[i]);
142 debugBelch("%d insns, %d slides, %d BCO_entries\n",
143 it_insns, it_slides, it_BCO_entries);
144 for (i = 0; i < 27; i++)
145 debugBelch("opcode %2d got %d\n", i, it_ofreq[i] );
147 for (k = 1; k < 20; k++) {
150 for (i = 0; i < 27; i++) {
151 for (j = 0; j < 27; j++) {
152 if (it_oofreq[i][j] > o_max) {
153 o_max = it_oofreq[i][j];
154 i_max = i; j_max = j;
159 debugBelch("%d: count (%4.1f%%) %6d is %d then %d\n",
160 k, ((double)o_max) * 100.0 / ((double)it_insns), o_max,
162 it_oofreq[i_max][j_max] = 0;
167 #else // !INTERP_STATS
169 #define INTERP_TICK(n) /* nothing */
173 static StgWord app_ptrs_itbl[] = {
176 (W_)&stg_ap_ppp_info,
177 (W_)&stg_ap_pppp_info,
178 (W_)&stg_ap_ppppp_info,
179 (W_)&stg_ap_pppppp_info,
182 HsStablePtr rts_breakpoint_io_action; // points to the IO action which is executed on a breakpoint
183 // it is set in main/GHC.hs:runStmt
186 interpretBCO (Capability* cap)
188 // Use of register here is primarily to make it clear to compilers
189 // that these entities are non-aliasable.
190 register StgPtr Sp; // local state -- stack pointer
191 register StgPtr SpLim; // local state -- stack lim pointer
192 register StgClosure *tagged_obj = 0, *obj;
197 // ------------------------------------------------------------------------
200 // We have a closure to evaluate. Stack looks like:
204 // Sp | -------------------> closure
207 if (Sp[0] == (W_)&stg_enter_info) {
212 // ------------------------------------------------------------------------
215 // We have a BCO application to perform. Stack looks like:
226 else if (Sp[0] == (W_)&stg_apply_interp_info) {
227 obj = UNTAG_CLOSURE((StgClosure *)Sp[1]);
232 // ------------------------------------------------------------------------
235 // We have an unboxed value to return. See comment before
236 // do_return_unboxed, below.
239 goto do_return_unboxed;
242 // Evaluate the object on top of the stack.
244 tagged_obj = (StgClosure*)Sp[0]; Sp++;
247 obj = UNTAG_CLOSURE(tagged_obj);
248 INTERP_TICK(it_total_evals);
250 IF_DEBUG(interpreter,
252 "\n---------------------------------------------------------------\n");
253 debugBelch("Evaluating: "); printObj(obj);
254 debugBelch("Sp = %p\n", Sp);
257 printStackChunk(Sp,cap->r.rCurrentTSO->stack+cap->r.rCurrentTSO->stack_size);
261 IF_DEBUG(sanity,checkStackChunk(Sp, cap->r.rCurrentTSO->stack+cap->r.rCurrentTSO->stack_size));
263 switch ( get_itbl(obj)->type ) {
268 case IND_OLDGEN_PERM:
271 tagged_obj = ((StgInd*)obj)->indirectee;
282 case CONSTR_NOCAF_STATIC:
296 ASSERT(((StgBCO *)obj)->arity > 0);
300 case AP: /* Copied from stg_AP_entry. */
309 if (Sp - (words+sizeofW(StgUpdateFrame)) < SpLim) {
311 Sp[1] = (W_)tagged_obj;
312 Sp[0] = (W_)&stg_enter_info;
313 RETURN_TO_SCHEDULER(ThreadInterpret, StackOverflow);
316 /* Ok; we're safe. Party on. Push an update frame. */
317 Sp -= sizeofW(StgUpdateFrame);
319 StgUpdateFrame *__frame;
320 __frame = (StgUpdateFrame *)Sp;
321 SET_INFO(__frame, (StgInfoTable *)&stg_upd_frame_info);
322 __frame->updatee = (StgClosure *)(ap);
325 /* Reload the stack */
327 for (i=0; i < words; i++) {
328 Sp[i] = (W_)ap->payload[i];
331 obj = UNTAG_CLOSURE((StgClosure*)ap->fun);
332 ASSERT(get_itbl(obj)->type == BCO);
341 j = get_itbl(obj)->type;
342 ASSERT(j >= 0 && j < N_CLOSURE_TYPES);
343 it_unknown_entries[j]++;
344 it_total_unknown_entries++;
348 // Can't handle this object; yield to scheduler
349 IF_DEBUG(interpreter,
350 debugBelch("evaluating unknown closure -- yielding to sched\n");
354 Sp[1] = (W_)tagged_obj;
355 Sp[0] = (W_)&stg_enter_info;
356 RETURN_TO_SCHEDULER_NO_PAUSE(ThreadRunGHC, ThreadYielding);
360 // ------------------------------------------------------------------------
361 // We now have an evaluated object (tagged_obj). The next thing to
362 // do is return it to the stack frame on top of the stack.
364 obj = UNTAG_CLOSURE(tagged_obj);
365 ASSERT(closure_HNF(obj));
367 IF_DEBUG(interpreter,
369 "\n---------------------------------------------------------------\n");
370 debugBelch("Returning: "); printObj(obj);
371 debugBelch("Sp = %p\n", Sp);
373 printStackChunk(Sp,cap->r.rCurrentTSO->stack+cap->r.rCurrentTSO->stack_size);
377 IF_DEBUG(sanity,checkStackChunk(Sp, cap->r.rCurrentTSO->stack+cap->r.rCurrentTSO->stack_size));
379 switch (get_itbl((StgClosure *)Sp)->type) {
382 const StgInfoTable *info;
384 // NOTE: not using get_itbl().
385 info = ((StgClosure *)Sp)->header.info;
386 if (info == (StgInfoTable *)&stg_ap_v_info) {
387 n = 1; m = 0; goto do_apply;
389 if (info == (StgInfoTable *)&stg_ap_f_info) {
390 n = 1; m = 1; goto do_apply;
392 if (info == (StgInfoTable *)&stg_ap_d_info) {
393 n = 1; m = sizeofW(StgDouble); goto do_apply;
395 if (info == (StgInfoTable *)&stg_ap_l_info) {
396 n = 1; m = sizeofW(StgInt64); goto do_apply;
398 if (info == (StgInfoTable *)&stg_ap_n_info) {
399 n = 1; m = 1; goto do_apply;
401 if (info == (StgInfoTable *)&stg_ap_p_info) {
402 n = 1; m = 1; goto do_apply;
404 if (info == (StgInfoTable *)&stg_ap_pp_info) {
405 n = 2; m = 2; goto do_apply;
407 if (info == (StgInfoTable *)&stg_ap_ppp_info) {
408 n = 3; m = 3; goto do_apply;
410 if (info == (StgInfoTable *)&stg_ap_pppp_info) {
411 n = 4; m = 4; goto do_apply;
413 if (info == (StgInfoTable *)&stg_ap_ppppp_info) {
414 n = 5; m = 5; goto do_apply;
416 if (info == (StgInfoTable *)&stg_ap_pppppp_info) {
417 n = 6; m = 6; goto do_apply;
419 goto do_return_unrecognised;
423 // Returning to an update frame: do the update, pop the update
424 // frame, and continue with the next stack frame.
426 // NB. we must update with the *tagged* pointer. Some tags
427 // are not optional, and if we omit the tag bits when updating
428 // then bad things can happen (albeit very rarely). See #1925.
429 // What happened was an indirection was created with an
430 // untagged pointer, and this untagged pointer was propagated
431 // to a PAP by the GC, violating the invariant that PAPs
432 // always contain a tagged pointer to the function.
433 INTERP_TICK(it_retto_UPDATE);
434 UPD_IND(((StgUpdateFrame *)Sp)->updatee, tagged_obj);
435 Sp += sizeofW(StgUpdateFrame);
439 // Returning to an interpreted continuation: put the object on
440 // the stack, and start executing the BCO.
441 INTERP_TICK(it_retto_BCO);
444 // NB. return the untagged object; the bytecode expects it to
445 // be untagged. XXX this doesn't seem right.
446 obj = (StgClosure*)Sp[2];
447 ASSERT(get_itbl(obj)->type == BCO);
451 do_return_unrecognised:
453 // Can't handle this return address; yield to scheduler
454 INTERP_TICK(it_retto_other);
455 IF_DEBUG(interpreter,
456 debugBelch("returning to unknown frame -- yielding to sched\n");
457 printStackChunk(Sp,cap->r.rCurrentTSO->stack+cap->r.rCurrentTSO->stack_size);
460 Sp[1] = (W_)tagged_obj;
461 Sp[0] = (W_)&stg_enter_info;
462 RETURN_TO_SCHEDULER_NO_PAUSE(ThreadRunGHC, ThreadYielding);
466 // -------------------------------------------------------------------------
467 // Returning an unboxed value. The stack looks like this:
484 // where XXXX_info is one of the stg_gc_unbx_r1_info family.
486 // We're only interested in the case when the real return address
487 // is a BCO; otherwise we'll return to the scheduler.
493 ASSERT( Sp[0] == (W_)&stg_gc_unbx_r1_info
494 || Sp[0] == (W_)&stg_gc_unpt_r1_info
495 || Sp[0] == (W_)&stg_gc_f1_info
496 || Sp[0] == (W_)&stg_gc_d1_info
497 || Sp[0] == (W_)&stg_gc_l1_info
498 || Sp[0] == (W_)&stg_gc_void_info // VoidRep
501 // get the offset of the stg_ctoi_ret_XXX itbl
502 offset = stack_frame_sizeW((StgClosure *)Sp);
504 switch (get_itbl((StgClosure *)Sp+offset)->type) {
507 // Returning to an interpreted continuation: put the object on
508 // the stack, and start executing the BCO.
509 INTERP_TICK(it_retto_BCO);
510 obj = (StgClosure*)Sp[offset+1];
511 ASSERT(get_itbl(obj)->type == BCO);
512 goto run_BCO_return_unboxed;
516 // Can't handle this return address; yield to scheduler
517 INTERP_TICK(it_retto_other);
518 IF_DEBUG(interpreter,
519 debugBelch("returning to unknown frame -- yielding to sched\n");
520 printStackChunk(Sp,cap->r.rCurrentTSO->stack+cap->r.rCurrentTSO->stack_size);
522 RETURN_TO_SCHEDULER_NO_PAUSE(ThreadRunGHC, ThreadYielding);
529 // -------------------------------------------------------------------------
533 ASSERT(obj == UNTAG_CLOSURE(tagged_obj));
534 // we have a function to apply (obj), and n arguments taking up m
535 // words on the stack. The info table (stg_ap_pp_info or whatever)
536 // is on top of the arguments on the stack.
538 switch (get_itbl(obj)->type) {
546 // we only cope with PAPs whose function is a BCO
547 if (get_itbl(UNTAG_CLOSURE(pap->fun))->type != BCO) {
548 goto defer_apply_to_sched;
555 // n must be greater than 1, and the only kinds of
556 // application we support with more than one argument
557 // are all pointers...
559 // Shuffle the args for this function down, and put
560 // the appropriate info table in the gap.
561 for (i = 0; i < arity; i++) {
562 Sp[(int)i-1] = Sp[i];
563 // ^^^^^ careful, i-1 might be negative, but i in unsigned
565 Sp[arity-1] = app_ptrs_itbl[n-arity-1];
567 // unpack the PAP's arguments onto the stack
569 for (i = 0; i < pap->n_args; i++) {
570 Sp[i] = (W_)pap->payload[i];
572 obj = UNTAG_CLOSURE(pap->fun);
575 else if (arity == n) {
577 for (i = 0; i < pap->n_args; i++) {
578 Sp[i] = (W_)pap->payload[i];
580 obj = UNTAG_CLOSURE(pap->fun);
583 else /* arity > n */ {
584 // build a new PAP and return it.
586 new_pap = (StgPAP *)allocate(PAP_sizeW(pap->n_args + m));
587 SET_HDR(new_pap,&stg_PAP_info,CCCS);
588 new_pap->arity = pap->arity - n;
589 new_pap->n_args = pap->n_args + m;
590 new_pap->fun = pap->fun;
591 for (i = 0; i < pap->n_args; i++) {
592 new_pap->payload[i] = pap->payload[i];
594 for (i = 0; i < m; i++) {
595 new_pap->payload[pap->n_args + i] = (StgClosure *)Sp[i];
597 tagged_obj = (StgClosure *)new_pap;
607 arity = ((StgBCO *)obj)->arity;
610 // n must be greater than 1, and the only kinds of
611 // application we support with more than one argument
612 // are all pointers...
614 // Shuffle the args for this function down, and put
615 // the appropriate info table in the gap.
616 for (i = 0; i < arity; i++) {
617 Sp[(int)i-1] = Sp[i];
618 // ^^^^^ careful, i-1 might be negative, but i in unsigned
620 Sp[arity-1] = app_ptrs_itbl[n-arity-1];
624 else if (arity == n) {
627 else /* arity > n */ {
628 // build a PAP and return it.
631 pap = (StgPAP *)allocate(PAP_sizeW(m));
632 SET_HDR(pap, &stg_PAP_info,CCCS);
633 pap->arity = arity - n;
636 for (i = 0; i < m; i++) {
637 pap->payload[i] = (StgClosure *)Sp[i];
639 tagged_obj = (StgClosure *)pap;
645 // No point in us applying machine-code functions
647 defer_apply_to_sched:
649 Sp[1] = (W_)tagged_obj;
650 Sp[0] = (W_)&stg_enter_info;
651 RETURN_TO_SCHEDULER_NO_PAUSE(ThreadRunGHC, ThreadYielding);
654 // ------------------------------------------------------------------------
655 // Ok, we now have a bco (obj), and its arguments are all on the
656 // stack. We can start executing the byte codes.
658 // The stack is in one of two states. First, if this BCO is a
668 // Second, if this BCO is a continuation:
683 // where retval is the value being returned to this continuation.
684 // In the event of a stack check, heap check, or context switch,
685 // we need to leave the stack in a sane state so the garbage
686 // collector can find all the pointers.
688 // (1) BCO is a function: the BCO's bitmap describes the
689 // pointerhood of the arguments.
691 // (2) BCO is a continuation: BCO's bitmap describes the
692 // pointerhood of the free variables.
694 // Sadly we have three different kinds of stack/heap/cswitch check
700 if (doYouWantToGC()) {
701 Sp--; Sp[0] = (W_)&stg_enter_info;
702 RETURN_TO_SCHEDULER(ThreadInterpret, HeapOverflow);
704 // Stack checks aren't necessary at return points, the stack use
705 // is aggregated into the enclosing function entry point.
709 run_BCO_return_unboxed:
711 if (doYouWantToGC()) {
712 RETURN_TO_SCHEDULER(ThreadInterpret, HeapOverflow);
714 // Stack checks aren't necessary at return points, the stack use
715 // is aggregated into the enclosing function entry point.
723 Sp[0] = (W_)&stg_apply_interp_info;
724 checkStackChunk(Sp,SpLim);
729 if (doYouWantToGC()) {
732 Sp[0] = (W_)&stg_apply_interp_info; // placeholder, really
733 RETURN_TO_SCHEDULER(ThreadInterpret, HeapOverflow);
737 if (Sp - INTERP_STACK_CHECK_THRESH < SpLim) {
740 Sp[0] = (W_)&stg_apply_interp_info; // placeholder, really
741 RETURN_TO_SCHEDULER(ThreadInterpret, StackOverflow);
746 // Now, actually interpret the BCO... (no returning to the
747 // scheduler again until the stack is in an orderly state).
749 INTERP_TICK(it_BCO_entries);
751 register int bciPtr = 1; /* instruction pointer */
752 register StgWord16 bci;
753 register StgBCO* bco = (StgBCO*)obj;
754 register StgWord16* instrs = (StgWord16*)(bco->instrs->payload);
755 register StgWord* literals = (StgWord*)(&bco->literals->payload[0]);
756 register StgPtr* ptrs = (StgPtr*)(&bco->ptrs->payload[0]);
759 it_lastopc = 0; /* no opcode */
763 ASSERT(bciPtr <= instrs[0]);
764 IF_DEBUG(interpreter,
765 //if (do_print_stack) {
766 //debugBelch("\n-- BEGIN stack\n");
767 //printStack(Sp,cap->r.rCurrentTSO->stack+cap->r.rCurrentTSO->stack_size,iSu);
768 //debugBelch("-- END stack\n\n");
770 debugBelch("Sp = %p pc = %d ", Sp, bciPtr);
771 disInstr(bco,bciPtr);
774 for (i = 8; i >= 0; i--) {
775 debugBelch("%d %p\n", i, (StgPtr)(*(Sp+i)));
779 //if (do_print_stack) checkStack(Sp,cap->r.rCurrentTSO->stack+cap->r.rCurrentTSO->stack_size,iSu);
783 INTERP_TICK(it_insns);
786 ASSERT( (int)instrs[bciPtr] >= 0 && (int)instrs[bciPtr] < 27 );
787 it_ofreq[ (int)instrs[bciPtr] ] ++;
788 it_oofreq[ it_lastopc ][ (int)instrs[bciPtr] ] ++;
789 it_lastopc = (int)instrs[bciPtr];
793 /* We use the high 8 bits for flags, only the highest of which is
794 * currently allocated */
795 ASSERT((bci & 0xFF00) == (bci & 0x8000));
797 switch (bci & 0xFF) {
799 /* check for a breakpoint on the beginning of a let binding */
802 int arg1_brk_array, arg2_array_index, arg3_freeVars;
803 StgArrWords *breakPoints;
804 int returning_from_break; // are we resuming execution from a breakpoint?
805 // if yes, then don't break this time around
806 StgClosure *ioAction; // the io action to run at a breakpoint
808 StgAP_STACK *new_aps; // a closure to save the top stack frame on the heap
812 arg1_brk_array = BCO_NEXT; // 1st arg of break instruction
813 arg2_array_index = BCO_NEXT; // 2nd arg of break instruction
814 arg3_freeVars = BCO_NEXT; // 3rd arg of break instruction
816 // check if we are returning from a breakpoint - this info
817 // is stored in the flags field of the current TSO
818 returning_from_break = cap->r.rCurrentTSO->flags & TSO_STOPPED_ON_BREAKPOINT;
820 // if we are returning from a break then skip this section
821 // and continue executing
822 if (!returning_from_break)
824 breakPoints = (StgArrWords *) BCO_PTR(arg1_brk_array);
826 // stop the current thread if either the
827 // "rts_stop_next_breakpoint" flag is true OR if the
828 // breakpoint flag for this particular expression is
830 if (rts_stop_next_breakpoint == rtsTrue ||
831 breakPoints->payload[arg2_array_index] == rtsTrue)
833 // make sure we don't automatically stop at the
835 rts_stop_next_breakpoint = rtsFalse;
837 // allocate memory for a new AP_STACK, enough to
838 // store the top stack frame plus an
839 // stg_apply_interp_info pointer and a pointer to
841 size_words = BCO_BITMAP_SIZE(obj) + 2;
842 new_aps = (StgAP_STACK *) allocate (AP_STACK_sizeW(size_words));
843 SET_HDR(new_aps,&stg_AP_STACK_info,CCS_SYSTEM);
844 new_aps->size = size_words;
845 new_aps->fun = &stg_dummy_ret_closure;
847 // fill in the payload of the AP_STACK
848 new_aps->payload[0] = (StgClosure *)&stg_apply_interp_info;
849 new_aps->payload[1] = (StgClosure *)obj;
851 // copy the contents of the top stack frame into the AP_STACK
852 for (i = 2; i < size_words; i++)
854 new_aps->payload[i] = (StgClosure *)Sp[i-2];
857 // prepare the stack so that we can call the
858 // rts_breakpoint_io_action and ensure that the stack is
859 // in a reasonable state for the GC and so that
860 // execution of this BCO can continue when we resume
861 ioAction = (StgClosure *) deRefStablePtr (rts_breakpoint_io_action);
864 Sp[7] = (W_)&stg_apply_interp_info;
865 Sp[6] = (W_)&stg_noforceIO_info; // see [unreg] below
866 Sp[5] = (W_)new_aps; // the AP_STACK
867 Sp[4] = (W_)BCO_PTR(arg3_freeVars); // the info about local vars of the breakpoint
868 Sp[3] = (W_)False_closure; // True <=> a breakpoint
869 Sp[2] = (W_)&stg_ap_pppv_info;
870 Sp[1] = (W_)ioAction; // apply the IO action to its two arguments above
871 Sp[0] = (W_)&stg_enter_info; // get ready to run the IO action
872 // Note [unreg]: in unregisterised mode, the return
873 // convention for IO is different. The
874 // stg_noForceIO_info stack frame is necessary to
875 // account for this difference.
877 // set the flag in the TSO to say that we are now
878 // stopping at a breakpoint so that when we resume
879 // we don't stop on the same breakpoint that we
880 // already stopped at just now
881 cap->r.rCurrentTSO->flags |= TSO_STOPPED_ON_BREAKPOINT;
883 // stop this thread and return to the scheduler -
884 // eventually we will come back and the IO action on
885 // the top of the stack will be executed
886 RETURN_TO_SCHEDULER_NO_PAUSE(ThreadRunGHC, ThreadYielding);
889 // record that this thread is not stopped at a breakpoint anymore
890 cap->r.rCurrentTSO->flags &= ~TSO_STOPPED_ON_BREAKPOINT;
892 // continue normal execution of the byte code instructions
897 // Explicit stack check at the beginning of a function
898 // *only* (stack checks in case alternatives are
899 // propagated to the enclosing function).
900 StgWord stk_words_reqd = BCO_GET_LARGE_ARG + 1;
901 if (Sp - stk_words_reqd < SpLim) {
904 Sp[0] = (W_)&stg_apply_interp_info;
905 RETURN_TO_SCHEDULER(ThreadInterpret, StackOverflow);
940 Sp[-1] = BCO_PTR(o1);
945 case bci_PUSH_ALTS: {
946 int o_bco = BCO_NEXT;
947 Sp[-2] = (W_)&stg_ctoi_R1p_info;
948 Sp[-1] = BCO_PTR(o_bco);
953 case bci_PUSH_ALTS_P: {
954 int o_bco = BCO_NEXT;
955 Sp[-2] = (W_)&stg_ctoi_R1unpt_info;
956 Sp[-1] = BCO_PTR(o_bco);
961 case bci_PUSH_ALTS_N: {
962 int o_bco = BCO_NEXT;
963 Sp[-2] = (W_)&stg_ctoi_R1n_info;
964 Sp[-1] = BCO_PTR(o_bco);
969 case bci_PUSH_ALTS_F: {
970 int o_bco = BCO_NEXT;
971 Sp[-2] = (W_)&stg_ctoi_F1_info;
972 Sp[-1] = BCO_PTR(o_bco);
977 case bci_PUSH_ALTS_D: {
978 int o_bco = BCO_NEXT;
979 Sp[-2] = (W_)&stg_ctoi_D1_info;
980 Sp[-1] = BCO_PTR(o_bco);
985 case bci_PUSH_ALTS_L: {
986 int o_bco = BCO_NEXT;
987 Sp[-2] = (W_)&stg_ctoi_L1_info;
988 Sp[-1] = BCO_PTR(o_bco);
993 case bci_PUSH_ALTS_V: {
994 int o_bco = BCO_NEXT;
995 Sp[-2] = (W_)&stg_ctoi_V_info;
996 Sp[-1] = BCO_PTR(o_bco);
1001 case bci_PUSH_APPLY_N:
1002 Sp--; Sp[0] = (W_)&stg_ap_n_info;
1004 case bci_PUSH_APPLY_V:
1005 Sp--; Sp[0] = (W_)&stg_ap_v_info;
1007 case bci_PUSH_APPLY_F:
1008 Sp--; Sp[0] = (W_)&stg_ap_f_info;
1010 case bci_PUSH_APPLY_D:
1011 Sp--; Sp[0] = (W_)&stg_ap_d_info;
1013 case bci_PUSH_APPLY_L:
1014 Sp--; Sp[0] = (W_)&stg_ap_l_info;
1016 case bci_PUSH_APPLY_P:
1017 Sp--; Sp[0] = (W_)&stg_ap_p_info;
1019 case bci_PUSH_APPLY_PP:
1020 Sp--; Sp[0] = (W_)&stg_ap_pp_info;
1022 case bci_PUSH_APPLY_PPP:
1023 Sp--; Sp[0] = (W_)&stg_ap_ppp_info;
1025 case bci_PUSH_APPLY_PPPP:
1026 Sp--; Sp[0] = (W_)&stg_ap_pppp_info;
1028 case bci_PUSH_APPLY_PPPPP:
1029 Sp--; Sp[0] = (W_)&stg_ap_ppppp_info;
1031 case bci_PUSH_APPLY_PPPPPP:
1032 Sp--; Sp[0] = (W_)&stg_ap_pppppp_info;
1035 case bci_PUSH_UBX: {
1037 int o_lits = BCO_NEXT;
1038 int n_words = BCO_NEXT;
1040 for (i = 0; i < n_words; i++) {
1041 Sp[i] = (W_)BCO_LIT(o_lits+i);
1049 /* a_1, .. a_n, b_1, .. b_by, s => a_1, .. a_n, s */
1054 INTERP_TICK(it_slides);
1058 case bci_ALLOC_AP: {
1060 int n_payload = BCO_NEXT;
1061 ap = (StgAP*)allocate(AP_sizeW(n_payload));
1063 ap->n_args = n_payload;
1064 SET_HDR(ap, &stg_AP_info, CCS_SYSTEM/*ToDo*/)
1069 case bci_ALLOC_AP_NOUPD: {
1071 int n_payload = BCO_NEXT;
1072 ap = (StgAP*)allocate(AP_sizeW(n_payload));
1074 ap->n_args = n_payload;
1075 SET_HDR(ap, &stg_AP_NOUPD_info, CCS_SYSTEM/*ToDo*/)
1080 case bci_ALLOC_PAP: {
1082 int arity = BCO_NEXT;
1083 int n_payload = BCO_NEXT;
1084 pap = (StgPAP*)allocate(PAP_sizeW(n_payload));
1086 pap->n_args = n_payload;
1088 SET_HDR(pap, &stg_PAP_info, CCS_SYSTEM/*ToDo*/)
1095 int stkoff = BCO_NEXT;
1096 int n_payload = BCO_NEXT;
1097 StgAP* ap = (StgAP*)Sp[stkoff];
1098 ASSERT((int)ap->n_args == n_payload);
1099 ap->fun = (StgClosure*)Sp[0];
1101 // The function should be a BCO, and its bitmap should
1102 // cover the payload of the AP correctly.
1103 ASSERT(get_itbl(ap->fun)->type == BCO
1104 && BCO_BITMAP_SIZE(ap->fun) == ap->n_args);
1106 for (i = 0; i < n_payload; i++)
1107 ap->payload[i] = (StgClosure*)Sp[i+1];
1109 IF_DEBUG(interpreter,
1110 debugBelch("\tBuilt ");
1111 printObj((StgClosure*)ap);
1118 int stkoff = BCO_NEXT;
1119 int n_payload = BCO_NEXT;
1120 StgPAP* pap = (StgPAP*)Sp[stkoff];
1121 ASSERT((int)pap->n_args == n_payload);
1122 pap->fun = (StgClosure*)Sp[0];
1124 // The function should be a BCO
1125 ASSERT(get_itbl(pap->fun)->type == BCO);
1127 for (i = 0; i < n_payload; i++)
1128 pap->payload[i] = (StgClosure*)Sp[i+1];
1130 IF_DEBUG(interpreter,
1131 debugBelch("\tBuilt ");
1132 printObj((StgClosure*)pap);
1138 /* Unpack N ptr words from t.o.s constructor */
1140 int n_words = BCO_NEXT;
1141 StgClosure* con = (StgClosure*)Sp[0];
1143 for (i = 0; i < n_words; i++) {
1144 Sp[i] = (W_)con->payload[i];
1151 int o_itbl = BCO_NEXT;
1152 int n_words = BCO_NEXT;
1153 StgInfoTable* itbl = INFO_PTR_TO_STRUCT(BCO_LIT(o_itbl));
1154 int request = CONSTR_sizeW( itbl->layout.payload.ptrs,
1155 itbl->layout.payload.nptrs );
1156 StgClosure* con = (StgClosure*)allocate_NONUPD(request);
1157 ASSERT( itbl->layout.payload.ptrs + itbl->layout.payload.nptrs > 0);
1158 SET_HDR(con, (StgInfoTable*)BCO_LIT(o_itbl), CCS_SYSTEM/*ToDo*/);
1159 for (i = 0; i < n_words; i++) {
1160 con->payload[i] = (StgClosure*)Sp[i];
1165 IF_DEBUG(interpreter,
1166 debugBelch("\tBuilt ");
1167 printObj((StgClosure*)con);
1172 case bci_TESTLT_P: {
1173 unsigned int discr = BCO_NEXT;
1174 int failto = BCO_NEXT;
1175 StgClosure* con = (StgClosure*)Sp[0];
1176 if (GET_TAG(con) >= discr) {
1182 case bci_TESTEQ_P: {
1183 unsigned int discr = BCO_NEXT;
1184 int failto = BCO_NEXT;
1185 StgClosure* con = (StgClosure*)Sp[0];
1186 if (GET_TAG(con) != discr) {
1192 case bci_TESTLT_I: {
1193 // There should be an Int at Sp[1], and an info table at Sp[0].
1194 int discr = BCO_NEXT;
1195 int failto = BCO_NEXT;
1196 I_ stackInt = (I_)Sp[1];
1197 if (stackInt >= (I_)BCO_LIT(discr))
1202 case bci_TESTEQ_I: {
1203 // There should be an Int at Sp[1], and an info table at Sp[0].
1204 int discr = BCO_NEXT;
1205 int failto = BCO_NEXT;
1206 I_ stackInt = (I_)Sp[1];
1207 if (stackInt != (I_)BCO_LIT(discr)) {
1213 case bci_TESTLT_D: {
1214 // There should be a Double at Sp[1], and an info table at Sp[0].
1215 int discr = BCO_NEXT;
1216 int failto = BCO_NEXT;
1217 StgDouble stackDbl, discrDbl;
1218 stackDbl = PK_DBL( & Sp[1] );
1219 discrDbl = PK_DBL( & BCO_LIT(discr) );
1220 if (stackDbl >= discrDbl) {
1226 case bci_TESTEQ_D: {
1227 // There should be a Double at Sp[1], and an info table at Sp[0].
1228 int discr = BCO_NEXT;
1229 int failto = BCO_NEXT;
1230 StgDouble stackDbl, discrDbl;
1231 stackDbl = PK_DBL( & Sp[1] );
1232 discrDbl = PK_DBL( & BCO_LIT(discr) );
1233 if (stackDbl != discrDbl) {
1239 case bci_TESTLT_F: {
1240 // There should be a Float at Sp[1], and an info table at Sp[0].
1241 int discr = BCO_NEXT;
1242 int failto = BCO_NEXT;
1243 StgFloat stackFlt, discrFlt;
1244 stackFlt = PK_FLT( & Sp[1] );
1245 discrFlt = PK_FLT( & BCO_LIT(discr) );
1246 if (stackFlt >= discrFlt) {
1252 case bci_TESTEQ_F: {
1253 // There should be a Float at Sp[1], and an info table at Sp[0].
1254 int discr = BCO_NEXT;
1255 int failto = BCO_NEXT;
1256 StgFloat stackFlt, discrFlt;
1257 stackFlt = PK_FLT( & Sp[1] );
1258 discrFlt = PK_FLT( & BCO_LIT(discr) );
1259 if (stackFlt != discrFlt) {
1265 // Control-flow ish things
1267 // Context-switch check. We put it here to ensure that
1268 // the interpreter has done at least *some* work before
1269 // context switching: sometimes the scheduler can invoke
1270 // the interpreter with context_switch == 1, particularly
1271 // if the -C0 flag has been given on the cmd line.
1272 if (context_switch) {
1273 Sp--; Sp[0] = (W_)&stg_enter_info;
1274 RETURN_TO_SCHEDULER(ThreadInterpret, ThreadYielding);
1279 tagged_obj = (StgClosure *)Sp[0];
1285 Sp[0] = (W_)&stg_gc_unpt_r1_info;
1286 goto do_return_unboxed;
1289 Sp[0] = (W_)&stg_gc_unbx_r1_info;
1290 goto do_return_unboxed;
1293 Sp[0] = (W_)&stg_gc_f1_info;
1294 goto do_return_unboxed;
1297 Sp[0] = (W_)&stg_gc_d1_info;
1298 goto do_return_unboxed;
1301 Sp[0] = (W_)&stg_gc_l1_info;
1302 goto do_return_unboxed;
1305 Sp[0] = (W_)&stg_gc_void_info;
1306 goto do_return_unboxed;
1309 int stkoff = BCO_NEXT;
1310 signed short n = (signed short)(BCO_NEXT);
1311 Sp[stkoff] += (W_)n;
1317 int stk_offset = BCO_NEXT;
1318 int o_itbl = BCO_NEXT;
1319 void(*marshall_fn)(void*) = (void (*)(void*))BCO_LIT(o_itbl);
1321 RET_DYN_BITMAP_SIZE + RET_DYN_NONPTR_REGS_SIZE
1322 + sizeofW(StgRetDyn);
1326 // Arguments on the TSO stack are not good, because garbage
1327 // collection might move the TSO as soon as we call
1328 // suspendThread below.
1330 W_ arguments[stk_offset];
1332 memcpy(arguments, Sp, sizeof(W_) * stk_offset);
1335 // Restore the Haskell thread's current value of errno
1336 errno = cap->r.rCurrentTSO->saved_errno;
1338 // There are a bunch of non-ptr words on the stack (the
1339 // ccall args, the ccall fun address and space for the
1340 // result), which we need to cover with an info table
1341 // since we might GC during this call.
1343 // We know how many (non-ptr) words there are before the
1344 // next valid stack frame: it is the stk_offset arg to the
1345 // CCALL instruction. So we build a RET_DYN stack frame
1346 // on the stack frame to describe this chunk of stack.
1349 ((StgRetDyn *)Sp)->liveness = R1_PTR | N_NONPTRS(stk_offset);
1350 ((StgRetDyn *)Sp)->info = (StgInfoTable *)&stg_gc_gen_info;
1352 // save obj (pointer to the current BCO), since this
1353 // might move during the call. We use the R1 slot in the
1354 // RET_DYN frame for this, hence R1_PTR above.
1355 ((StgRetDyn *)Sp)->payload[0] = (StgClosure *)obj;
1357 SAVE_STACK_POINTERS;
1358 tok = suspendThread(&cap->r);
1360 #ifndef THREADED_RTS
1362 // suspendThread might have shifted the stack
1363 // around (stack squeezing), so we have to grab the real
1364 // Sp out of the TSO to find the ccall args again.
1366 marshall_fn ( (void*)(cap->r.rCurrentTSO->sp + ret_dyn_size) );
1369 // We already made a copy of the arguments above.
1371 marshall_fn ( arguments );
1374 // And restart the thread again, popping the RET_DYN frame.
1375 cap = (Capability *)((void *)((unsigned char*)resumeThread(tok) - sizeof(StgFunTable)));
1376 LOAD_STACK_POINTERS;
1378 // Re-load the pointer to the BCO from the RET_DYN frame,
1379 // it might have moved during the call. Also reload the
1380 // pointers to the components of the BCO.
1381 obj = ((StgRetDyn *)Sp)->payload[0];
1383 instrs = (StgWord16*)(bco->instrs->payload);
1384 literals = (StgWord*)(&bco->literals->payload[0]);
1385 ptrs = (StgPtr*)(&bco->ptrs->payload[0]);
1389 // Save the Haskell thread's current value of errno
1390 cap->r.rCurrentTSO->saved_errno = errno;
1394 // Copy the "arguments", which might include a return value,
1395 // back to the TSO stack. It would of course be enough to
1396 // just copy the return value, but we don't know the offset.
1397 memcpy(Sp, arguments, sizeof(W_) * stk_offset);
1404 /* BCO_NEXT modifies bciPtr, so be conservative. */
1405 int nextpc = BCO_NEXT;
1411 barf("interpretBCO: hit a CASEFAIL");
1415 barf("interpretBCO: unknown or unimplemented opcode %d",
1418 } /* switch on opcode */
1422 barf("interpretBCO: fell off end of the interpreter");