* Copyright (c) 1994-2000.
*
* $RCSfile: Interpreter.c,v $
- * $Revision: 1.13 $
- * $Date: 2001/01/15 16:55:25 $
+ * $Revision: 1.14 $
+ * $Date: 2001/02/05 17:27:48 $
* ---------------------------------------------------------------------------*/
#ifdef GHCI
* The new bytecode interpreter
* ------------------------------------------------------------------------*/
-/* Sp points to the lowest live word on the stack. */
+/* The interpreter can be compiled so it just interprets BCOs and
+ hands literally everything else to the scheduler. This gives a
+ "reference interpreter" which is correct but slow -- useful for
+ debugging. By default, we handle certain closures specially so as
+ to dramatically cut down on the number of deferrals to the
+ scheduler. Ie normally you don't want REFERENCE_INTERPRETER to be
+ defined. */
+
+/* #define REFERENCE_INTERPRETER */
+
+/* Gather stats about entry, opcode, opcode-pair frequencies. For
+ tuning the interpreter. */
+
+/* #define INTERP_STATS */
+
+
+
+/* iSp points to the lowest live word on the stack. */
#define StackWord(n) iSp[n]
#define BCO_NEXT instrs[bciPtr++]
static __inline__ StgPtr allocate_UPD ( int n_words )
{
- //fprintf(stderr, "alloc_UPD %d -> ", n_words );
if (n_words - sizeofW(StgHeader) < MIN_UPD_SIZE)
n_words = MIN_UPD_SIZE + sizeofW(StgHeader);
- //fprintf(stderr, "%d\n", n_words );
return allocate(n_words);
}
static __inline__ StgPtr allocate_NONUPD ( int n_words )
{
- //fprintf(stderr, "alloc_NONUPD %d -> ", n_words );
if (n_words - sizeofW(StgHeader) < MIN_NONUPD_SIZE)
n_words = MIN_NONUPD_SIZE + sizeofW(StgHeader);
- //fprintf(stderr, "%d\n", n_words );
return allocate(n_words);
}
+#ifdef INTERP_STATS
+/* Hacky stats, for tuning the interpreter ... */
+int it_unknown_entries[N_CLOSURE_TYPES];
+int it_total_unknown_entries;
+int it_total_entries;
+
+int it_retto_BCO;
+int it_retto_UPDATE;
+int it_retto_other;
+
+int it_slides;
+int it_insns;
+int it_BCO_entries;
+
+int it_ofreq[26];
+int it_oofreq[26][26];
+int it_lastopc;
+
+void interp_startup ( void )
+{
+ int i, j;
+ it_retto_BCO = it_retto_UPDATE = it_retto_other = 0;
+ it_total_entries = it_total_unknown_entries = 0;
+ for (i = 0; i < N_CLOSURE_TYPES; i++)
+ it_unknown_entries[i] = 0;
+ it_slides = it_insns = it_BCO_entries = 0;
+ for (i = 0; i < 26; i++) it_ofreq[i] = 0;
+ for (i = 0; i < 26; i++)
+ for (j = 0; j < 26; j++)
+ it_oofreq[i][j] = 0;
+ it_lastopc = 0;
+}
+
+void interp_shutdown ( void )
+{
+ int i, j, k, o_max, i_max, j_max;
+ fprintf(stderr, "%d constrs entered -> (%d BCO, %d UPD, %d ???)\n",
+ it_retto_BCO + it_retto_UPDATE + it_retto_other,
+ it_retto_BCO, it_retto_UPDATE, it_retto_other );
+ fprintf(stderr, "%d total entries, %d unknown entries \n",
+ it_total_entries, it_total_unknown_entries);
+ for (i = 0; i < N_CLOSURE_TYPES; i++) {
+ if (it_unknown_entries[i] == 0) continue;
+ fprintf(stderr, " type %2d: unknown entries (%4.1f%%) == %d\n",
+ i, 100.0 * ((double)it_unknown_entries[i]) /
+ ((double)it_total_unknown_entries),
+ it_unknown_entries[i]);
+ }
+ fprintf(stderr, "%d insns, %d slides, %d BCO_entries\n",
+ it_insns, it_slides, it_BCO_entries);
+ for (i = 0; i < 26; i++)
+ fprintf(stderr, "opcode %2d got %d\n", i, it_ofreq[i] );
+
+ for (k = 1; k < 20; k++) {
+ o_max = 0;
+ i_max = j_max = 0;
+ for (i = 0; i < 26; i++) {
+ for (j = 0; j < 26; j++) {
+ if (it_oofreq[i][j] > o_max) {
+ o_max = it_oofreq[i][j];
+ i_max = i; j_max = j;
+ }
+ }
+ }
+
+ fprintf ( stderr, "%d: count (%4.1f%%) %6d is %d then %d\n",
+ k, ((double)o_max) * 100.0 / ((double)it_insns), o_max,
+ i_max, j_max );
+ it_oofreq[i_max][j_max] = 0;
+
+ }
+}
+#endif
+
+
StgThreadReturnCode interpretBCO ( Capability* cap )
{
/* On entry, the closure to interpret is on the top of the
LOAD_STACK_POINTERS;
+ /* We don't change this ... */
iSpLim = cap->rCurrentTSO->stack + RESERVED_STACK_WORDS;
/* Main object-entering loop. Object to be entered is on top of
obj = (StgClosure*)StackWord(0); iSp++;
+ nextEnter_obj:
+
+# ifdef INTERP_STATS
+ it_total_entries++;
+# endif
+
IF_DEBUG(evaluator,
fprintf(stderr,
"\n---------------------------------------------------------------\n");
fprintf(stderr, "\n\n");
);
+
+
switch ( get_itbl(obj)->type ) {
+
case INVALID_OBJECT:
barf("Invalid object %p",(StgPtr)obj);
-#if 0
+# ifndef REFERENCE_INTERPRETER
+
+ case IND:
+ case IND_OLDGEN:
+ case IND_PERM:
+ case IND_OLDGEN_PERM:
+ case IND_STATIC:
+ {
+ obj = ((StgInd*)obj)->indirectee;
+ goto nextEnter_obj;
+ }
+
+ case CONSTR:
+ case CONSTR_1_0:
+ case CONSTR_0_1:
+ case CONSTR_2_0:
+ case CONSTR_1_1:
+ case CONSTR_0_2:
+ case CONSTR_INTLIKE:
+ case CONSTR_CHARLIKE:
+ case CONSTR_STATIC:
+ case CONSTR_NOCAF_STATIC:
+ nextEnter_obj_CONSTR:
+ {
+ StgInfoTable* ret_itbl = (StgInfoTable*)StackWord(0);
+ if (ret_itbl == (StgInfoTable*)&stg_ctoi_ret_R1p_info) {
+# ifdef INTERP_STATS
+ it_retto_BCO++;
+# endif
+ /* Returning this constr to a BCO. Push the constr on
+ the stack and enter the return continuation BCO, which
+ is immediately underneath ret_itbl. */
+ StackWord(-1) = (W_)obj;
+ obj = (StgClosure*)StackWord(1);
+ iSp --;
+ if (get_itbl(obj)->type == BCO)
+ goto nextEnter_obj_BCO; /* fast-track common case */
+ else
+ goto nextEnter_obj; /* a safe fallback */
+ } else
+ if (ret_itbl == (StgInfoTable*)&stg_upd_frame_info) {
+# ifdef INTERP_STATS
+ it_retto_UPDATE++;
+# endif
+ /* Returning this constr to an update frame. Do the
+ update and re-enter the constr. */
+ ASSERT((W_*)iSu == iSp);
+ UPD_IND(iSu->updatee, obj);
+ iSu = iSu->link;
+ iSp += sizeofW(StgUpdateFrame);
+ goto nextEnter_obj_CONSTR;
+ }
+# ifdef INTERP_STATS
+ else it_retto_other++;
+# endif
+ goto defer_to_sched;
+ }
+
case AP_UPD:
- { nat Words;
- nat i;
+ /* Copied from stg_AP_UPD_entry. */
+ {
+ nat i, words;
StgAP_UPD *ap = (StgAP_UPD*)obj;
- Words = ap->n_args;
+ words = ap->n_args;
- /* WARNING: do a stack overflow check here !
- This code (copied from stg_AP_UPD_entry) is not correct without it. */
+ /* Stack check. If a stack overflow might occur, don't enter
+ the closure; let the scheduler handle it instead. */
+ if (iSp - (words+sizeofW(StgUpdateFrame)) < iSpLim)
+ goto defer_to_sched;
+ /* Ok; we're safe. Party on. Push an update frame. */
iSp -= sizeofW(StgUpdateFrame);
-
{
StgUpdateFrame *__frame;
__frame = (StgUpdateFrame *)iSp;
iSu = __frame;
}
- iSp -= Words;
-
/* Reload the stack */
- for (i=0; i<Words; i++) StackWord(i) = (W_)ap->payload[i];
+ iSp -= words;
+ for (i=0; i < words; i++) StackWord(i) = (W_)ap->payload[i];
- iSp--; StackWord(0) = (W_)ap->fun;
- goto nextEnter;
- }
-#endif
+ obj = (StgClosure*)ap->fun;
+ goto nextEnter_obj;
+ }
- case BCO:
+ case PAP:
+ /* Copied from stg_PAP_entry. */
+ {
+ nat words, i;
+ StgPAP* pap = (StgPAP *)obj;
+
+ /*
+ * remove any update frames on the top of the stack, by just
+ * performing the update here.
+ */
+ while ((W_)iSu - (W_)iSp == 0) {
+
+ switch (get_itbl(iSu)->type) {
+
+ case UPDATE_FRAME:
+ /* We're sitting on top of an update frame, so let's
+ do the business. */
+ UPD_IND(iSu->updatee, pap);
+ iSu = iSu->link;
+ iSp += sizeofW(StgUpdateFrame);
+ continue;
+
+ case SEQ_FRAME:
+ /* Too complicated ... adopt the Usual Solution. */
+ fprintf(stderr, "!!! SEQ frame in PAP update\n");
+ goto defer_to_sched;
+
+ case CATCH_FRAME:
+ /* can't happen, see stg_update_PAP */
+ barf("interpretBCO: PAP_entry: CATCH_FRAME");
+
+ default:
+ barf("interpretBCO: PAP_entry: strange activation record");
+ }
+ }
+
+ words = pap->n_args;
+
+ /* Stack check. If a stack overflow might occur, don't enter
+ the closure; let the scheduler handle it instead. */
+ if (iSp - words < iSpLim)
+ goto defer_to_sched;
+
+ /* Ok; safe. */
+ iSp -= words;
+ for (i=0; i < words; i++) StackWord(i) = (W_)pap->payload[i];
+
+ obj = (StgClosure*)pap->fun;
+ goto nextEnter_obj;
+ }
+
+# endif /* ndef REFERENCE_INTERPRETER */
+ case BCO:
/* ---------------------------------------------------- */
/* Start of the bytecode interpreter */
/* ---------------------------------------------------- */
+ nextEnter_obj_BCO:
+# ifdef INTERP_STATS
+ it_BCO_entries++;
+# endif
{
int do_print_stack = 1;
register int bciPtr = 1; /* instruction pointer */
if (doYouWantToGC()) {
iSp--; StackWord(0) = (W_)bco;
+ cap->rCurrentTSO->what_next = ThreadEnterGHC;
RETURN(HeapOverflow);
}
+# ifdef INTERP_STATS
+ it_lastopc = 0; /* no opcode */
+# endif
+
nextInsn:
ASSERT(bciPtr <= instrs[0]);
//if (do_print_stack) checkStack(iSp,cap->rCurrentTSO->stack+cap->rCurrentTSO->stack_size,iSu);
);
+# ifdef INTERP_STATS
+ it_insns++;
+ ASSERT( (int)instrs[bciPtr] >= 0 && (int)instrs[bciPtr] < 26 );
+ it_ofreq[ (int)instrs[bciPtr] ] ++;
+ it_oofreq[ it_lastopc ][ (int)instrs[bciPtr] ] ++;
+ it_lastopc = (int)instrs[bciPtr];
+# endif
switch (BCO_NEXT) {
int arg_words_reqd = BCO_NEXT;
int arg_words_avail = ((W_*)iSu) - ((W_*)iSp);
if (arg_words_avail >= arg_words_reqd) goto nextInsn;
- /* Handle arg check failure. Copy the spare args
- into a PAP frame. */
- /* fprintf(stderr, "arg check fail %d %d\n", arg_words_reqd, arg_words_avail ); */
+
+# ifndef REFERENCE_INTERPRETER
+
+ /* Optimisation: if there are no args avail and the
+ t-o-s is an update frame, do the update, and
+ re-enter the object. */
+ if (arg_words_avail == 0
+ && get_itbl(iSu)->type == UPDATE_FRAME) {
+ UPD_IND(iSu->updatee, obj);
+ iSu = iSu->link;
+ iSp += sizeofW(StgUpdateFrame);
+ goto nextEnter_obj_BCO;
+ }
+
+# endif /* ndef REFERENCE_INTERPRETER */
+
+ /* Handle arg check failure. General case: copy the
+ spare args into a PAP frame. */
pap = (StgPAP*)allocate_UPD(PAP_sizeW(arg_words_avail));
SET_HDR(pap,&stg_PAP_info,CCS_SYSTEM/*ToDo*/);
pap->n_args = arg_words_avail;
pap->fun = obj;
for (i = 0; i < arg_words_avail; i++)
pap->payload[i] = (StgClosure*)StackWord(i);
+
/* Push on the stack and defer to the scheduler. */
iSp = (StgPtr)iSu;
iSp --;
fprintf(stderr,"\tBuilt ");
printObj((StgClosure*)pap);
);
- RETURN(ThreadEnterGHC);
+ cap->rCurrentTSO->what_next = ThreadEnterGHC;
+ RETURN(ThreadYielding);
}
case bci_PUSH_L: {
int o1 = BCO_NEXT;
case bci_PUSH_LL: {
int o1 = BCO_NEXT;
int o2 = BCO_NEXT;
+ ASSERT((W_*)iSp+o1 < (W_*)iSu);
+ ASSERT((W_*)iSp+o2 < (W_*)iSu);
StackWord(-1) = StackWord(o1);
StackWord(-2) = StackWord(o2);
iSp -= 2;
int o1 = BCO_NEXT;
int o2 = BCO_NEXT;
int o3 = BCO_NEXT;
+ ASSERT((W_*)iSp+o1 < (W_*)iSu);
+ ASSERT((W_*)iSp+o2 < (W_*)iSu);
+ ASSERT((W_*)iSp+o3 < (W_*)iSu);
StackWord(-1) = StackWord(o1);
StackWord(-2) = StackWord(o2);
StackWord(-3) = StackWord(o3);
StackWord(n+by) = StackWord(n);
}
iSp += by;
+# ifdef INTERP_STATS
+ it_slides++;
+# endif
goto nextInsn;
}
case bci_ALLOC: {
int request = CONSTR_sizeW( itbl->layout.payload.ptrs,
itbl->layout.payload.nptrs );
StgClosure* con = (StgClosure*)allocate_NONUPD(request);
- //fprintf(stderr, "---PACK p %d, np %d\n",
- // (int) itbl->layout.payload.ptrs,
- // (int) itbl->layout.payload.nptrs );
ASSERT( itbl->layout.payload.ptrs + itbl->layout.payload.nptrs > 0);
SET_HDR(con, BCO_ITBL(o_itbl), CCS_SYSTEM/*ToDo*/);
for (i = 0; i < n_words; i++)
compiled-code return. */
StgInfoTable* magic_itbl = BCO_ITBL(o_itoc_itbl);
StackWord(0) = (W_)magic_itbl;
- RETURN(ThreadRunGHC);
+ cap->rCurrentTSO->what_next = ThreadRunGHC;
+ RETURN(ThreadYielding);
}
}
/* End of the bytecode interpreter */
/* ---------------------------------------------------- */
+ defer_to_sched:
default: {
+# ifdef INTERP_STATS
+ { int j = get_itbl(obj)->type;
+ ASSERT(j >= 0 && j < N_CLOSURE_TYPES);
+ it_unknown_entries[j]++;
+ it_total_unknown_entries++;
+ }
+# endif
+
/* Can't handle this object; yield to sched. */
IF_DEBUG(evaluator,
fprintf(stderr, "entering unknown closure -- yielding to sched\n");
printObj(obj);
- )
- cap->rCurrentTSO->what_next = ThreadEnterGHC;
+ );
iSp--; StackWord(0) = (W_)obj;
+ cap->rCurrentTSO->what_next = ThreadEnterGHC;
RETURN(ThreadYielding);
}
} /* switch on object kind */
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