1 /*------------------------------------------------------------------------
3 SDCCralloc.c - source file for register allocation. (8051) specific
5 Written By - Sandeep Dutta . sandeep.dutta@usa.net (1998)
7 This program is free software; you can redistribute it and/or modify it
8 under the terms of the GNU General Public License as published by the
9 Free Software Foundation; either version 2, or (at your option) any
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program; if not, write to the Free Software
19 Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
21 In other words, you are welcome to use, share and improve this program.
22 You are forbidden to forbid anyone else to use, share and improve
23 what you give them. Help stamp out software-hoarding!
24 -------------------------------------------------------------------------*/
30 /*-----------------------------------------------------------------*/
31 /* At this point we start getting processor specific although */
32 /* some routines are non-processor specific & can be reused when */
33 /* targetting other processors. The decision for this will have */
34 /* to be made on a routine by routine basis */
35 /* routines used to pack registers are most definitely not reusable*/
36 /* since the pack the registers depending strictly on the MCU */
37 /*-----------------------------------------------------------------*/
39 extern void gen51Code(iCode *);
48 bitVect *funcrUsed; /* registers used in a function */
53 /* Shared with gen.c */
54 int mcs51_ptrRegReq; /* one byte pointer register required */
60 { REG_GPR ,R2_IDX , REG_GPR , "r2", "ar2", "0", 2, 1 },
61 { REG_GPR ,R3_IDX , REG_GPR , "r3", "ar3", "0", 3, 1 },
62 { REG_GPR ,R4_IDX , REG_GPR , "r4", "ar4", "0", 4, 1 },
63 { REG_GPR ,R5_IDX , REG_GPR , "r5", "ar5", "0", 5, 1 },
64 { REG_GPR ,R6_IDX , REG_GPR , "r6", "ar6", "0", 6, 1 },
65 { REG_GPR ,R7_IDX , REG_GPR , "r7", "ar7", "0", 7, 1 },
66 { REG_PTR ,R0_IDX , REG_PTR , "r0" , "ar0", "0", 0, 1 },
67 { REG_PTR ,R1_IDX , REG_PTR , "r1" , "ar1", "0", 1, 1 },
68 { REG_GPR ,X8_IDX , REG_GPR , "x8", "x8" , "xreg", 0, 1 },
69 { REG_GPR ,X9_IDX , REG_GPR , "x9", "x9" , "xreg", 1, 1 },
70 { REG_GPR ,X10_IDX,REG_GPR , "x10", "x10", "xreg", 2, 1 },
71 { REG_GPR ,X11_IDX,REG_GPR , "x11", "x11", "xreg", 3, 1 },
72 { REG_GPR ,X12_IDX,REG_GPR , "x12", "x12", "xreg", 4, 1 },
73 { REG_CND ,CND_IDX,REG_CND , "C" , "C" , "xreg", 0, 1 },
76 static void spillThis (symbol *);
78 /*-----------------------------------------------------------------*/
79 /* allocReg - allocates register of given type */
80 /*-----------------------------------------------------------------*/
81 static regs *allocReg (short type)
85 for ( i = 0 ; i < mcs51_nRegs ; i++ ) {
87 /* if type is given as 0 then any
88 free register will do */
90 regs8051[i].isFree ) {
91 regs8051[i].isFree = 0;
94 bitVectSetBit(currFunc->regsUsed,i);
97 /* other wise look for specific type
99 if (regs8051[i].isFree &&
100 regs8051[i].type == type) {
101 regs8051[i].isFree = 0;
104 bitVectSetBit(currFunc->regsUsed,i);
111 /*-----------------------------------------------------------------*/
112 /* mcs51_regWithIdx - returns pointer to register wit index number */
113 /*-----------------------------------------------------------------*/
114 regs *mcs51_regWithIdx (int idx)
118 for (i=0;i < mcs51_nRegs;i++)
119 if (regs8051[i].rIdx == idx)
122 werror(E_INTERNAL_ERROR,__FILE__,__LINE__,
123 "regWithIdx not found");
127 /*-----------------------------------------------------------------*/
128 /* freeReg - frees a register */
129 /*-----------------------------------------------------------------*/
130 static void freeReg (regs *reg)
136 /*-----------------------------------------------------------------*/
137 /* nFreeRegs - returns number of free registers */
138 /*-----------------------------------------------------------------*/
139 static int nFreeRegs (int type)
144 for (i = 0 ; i < mcs51_nRegs; i++ )
145 if (regs8051[i].isFree && regs8051[i].type == type)
150 /*-----------------------------------------------------------------*/
151 /* nfreeRegsType - free registers with type */
152 /*-----------------------------------------------------------------*/
153 static int nfreeRegsType (int type)
156 if (type == REG_PTR) {
157 if ((nfr = nFreeRegs(type)) == 0)
158 return nFreeRegs(REG_GPR);
161 return nFreeRegs(type);
165 /*-----------------------------------------------------------------*/
166 /* allDefsOutOfRange - all definitions are out of a range */
167 /*-----------------------------------------------------------------*/
168 static bool allDefsOutOfRange (bitVect *defs,int fseq, int toseq)
175 for ( i = 0 ;i < defs->size ; i++ ) {
178 if (bitVectBitValue(defs,i) &&
179 (ic = hTabItemWithKey(iCodehTab,i)) &&
180 ( ic->seq >= fseq && ic->seq <= toseq))
189 /*-----------------------------------------------------------------*/
190 /* computeSpillable - given a point find the spillable live ranges */
191 /*-----------------------------------------------------------------*/
192 static bitVect *computeSpillable (iCode *ic)
196 /* spillable live ranges are those that are live at this
197 point . the following categories need to be subtracted
199 a) - those that are already spilt
200 b) - if being used by this one
201 c) - defined by this one */
203 spillable = bitVectCopy(ic->rlive);
205 bitVectCplAnd(spillable,_G.spiltSet); /* those already spilt */
207 bitVectCplAnd(spillable,ic->uses); /* used in this one */
208 bitVectUnSetBit(spillable,ic->defKey);
209 spillable = bitVectIntersect(spillable,_G.regAssigned);
214 /*-----------------------------------------------------------------*/
215 /* noSpilLoc - return true if a variable has no spil location */
216 /*-----------------------------------------------------------------*/
217 static int noSpilLoc (symbol *sym, eBBlock *ebp,iCode *ic)
219 return (sym->usl.spillLoc ? 0 : 1);
222 /*-----------------------------------------------------------------*/
223 /* hasSpilLoc - will return 1 if the symbol has spil location */
224 /*-----------------------------------------------------------------*/
225 static int hasSpilLoc (symbol *sym, eBBlock *ebp, iCode *ic)
227 return (sym->usl.spillLoc ? 1 : 0);
230 /*-----------------------------------------------------------------*/
231 /* directSpilLoc - will return 1 if the splilocation is in direct */
232 /*-----------------------------------------------------------------*/
233 static int directSpilLoc (symbol *sym, eBBlock *ebp, iCode *ic)
235 if ( sym->usl.spillLoc &&
236 (IN_DIRSPACE(SPEC_OCLS(sym->usl.spillLoc->etype))))
242 /*-----------------------------------------------------------------*/
243 /* hasSpilLocnoUptr - will return 1 if the symbol has spil location*/
244 /* but is not used as a pointer */
245 /*-----------------------------------------------------------------*/
246 static int hasSpilLocnoUptr (symbol *sym, eBBlock *ebp, iCode *ic)
248 return ((sym->usl.spillLoc && !sym->uptr) ? 1 : 0);
251 /*-----------------------------------------------------------------*/
252 /* rematable - will return 1 if the remat flag is set */
253 /*-----------------------------------------------------------------*/
254 static int rematable (symbol *sym, eBBlock *ebp, iCode *ic)
259 /*-----------------------------------------------------------------*/
260 /* notUsedInBlock - not used in this block */
261 /*-----------------------------------------------------------------*/
262 static int notUsedInBlock (symbol *sym, eBBlock *ebp, iCode *ic)
264 return (!bitVectBitsInCommon(sym->defs,ebp->usesDefs) &&
265 allDefsOutOfRange (sym->defs,ebp->fSeq,ebp->lSeq));
266 /* return (!bitVectBitsInCommon(sym->defs,ebp->usesDefs)); */
269 /*-----------------------------------------------------------------*/
270 /* notUsedInRemaining - not used or defined in remain of the block */
271 /*-----------------------------------------------------------------*/
272 static int notUsedInRemaining (symbol *sym, eBBlock *ebp, iCode *ic)
274 return ((usedInRemaining (operandFromSymbol(sym),ic) ? 0 : 1) &&
275 allDefsOutOfRange (sym->defs,ic->seq,ebp->lSeq));
278 /*-----------------------------------------------------------------*/
279 /* allLRs - return true for all */
280 /*-----------------------------------------------------------------*/
281 static int allLRs (symbol *sym, eBBlock *ebp, iCode *ic)
286 /*-----------------------------------------------------------------*/
287 /* liveRangesWith - applies function to a given set of live range */
288 /*-----------------------------------------------------------------*/
289 static set *liveRangesWith (bitVect *lrs, int (func)(symbol *,eBBlock *, iCode *),
290 eBBlock *ebp, iCode *ic)
295 if (!lrs || !lrs->size)
298 for ( i = 1 ; i < lrs->size ; i++ ) {
300 if (!bitVectBitValue(lrs,i))
303 /* if we don't find it in the live range
304 hash table we are in serious trouble */
305 if (!(sym = hTabItemWithKey(liveRanges,i))) {
306 werror(E_INTERNAL_ERROR,__FILE__,__LINE__,
307 "liveRangesWith could not find liveRange");
311 if (func(sym,ebp,ic) && bitVectBitValue(_G.regAssigned,sym->key))
312 addSetHead(&rset,sym);
319 /*-----------------------------------------------------------------*/
320 /* leastUsedLR - given a set determines which is the least used */
321 /*-----------------------------------------------------------------*/
322 static symbol *leastUsedLR (set *sset)
324 symbol *sym = NULL, *lsym = NULL ;
326 sym = lsym = setFirstItem(sset);
331 for (; lsym; lsym = setNextItem(sset)) {
333 /* if usage is the same then prefer
334 the spill the smaller of the two */
335 if ( lsym->used == sym->used )
336 if (getSize(lsym->type) < getSize(sym->type))
340 if (lsym->used < sym->used )
345 setToNull((void **)&sset);
350 /*-----------------------------------------------------------------*/
351 /* noOverLap - will iterate through the list looking for over lap */
352 /*-----------------------------------------------------------------*/
353 static int noOverLap (set *itmpStack, symbol *fsym)
358 for (sym = setFirstItem(itmpStack); sym;
359 sym = setNextItem(itmpStack)) {
360 if (sym->liveTo > fsym->liveFrom )
368 /*-----------------------------------------------------------------*/
369 /* isFree - will return 1 if the a free spil location is found */
370 /*-----------------------------------------------------------------*/
371 static DEFSETFUNC(isFree)
374 V_ARG(symbol **,sloc);
375 V_ARG(symbol *,fsym);
377 /* if already found */
381 /* if it is free && and the itmp assigned to
382 this does not have any overlapping live ranges
383 with the one currently being assigned and
384 the size can be accomodated */
386 noOverLap(sym->usl.itmpStack,fsym) &&
387 getSize(sym->type) >= getSize(fsym->type)) {
395 /*-----------------------------------------------------------------*/
396 /* spillLRWithPtrReg :- will spil those live ranges which use PTR */
397 /*-----------------------------------------------------------------*/
398 static void spillLRWithPtrReg (symbol *forSym)
404 if (!_G.regAssigned ||
405 bitVectIsZero(_G.regAssigned))
408 r0 = mcs51_regWithIdx(R0_IDX);
409 r1 = mcs51_regWithIdx(R1_IDX);
411 /* for all live ranges */
412 for (lrsym = hTabFirstItem(liveRanges,&k) ; lrsym ;
413 lrsym = hTabNextItem(liveRanges,&k) ) {
416 /* if no registers assigned to it or
418 /* if it does not overlap with this then
419 not need to spill it */
421 if (lrsym->isspilt || !lrsym->nRegs ||
422 (lrsym->liveTo < forSym->liveFrom))
425 /* go thru the registers : if it is either
426 r0 or r1 then spil it */
427 for (j = 0 ; j < lrsym->nRegs ; j++ )
428 if (lrsym->regs[j] == r0 ||
429 lrsym->regs[j] == r1 ) {
437 /*-----------------------------------------------------------------*/
438 /* createStackSpil - create a location on the stack to spil */
439 /*-----------------------------------------------------------------*/
440 static symbol *createStackSpil (symbol *sym)
443 int useXstack, model, noOverlay;
447 /* first go try and find a free one that is already
448 existing on the stack */
449 if (applyToSet(_G.stackSpil,isFree,&sloc, sym)) {
450 /* found a free one : just update & return */
451 sym->usl.spillLoc = sloc;
454 addSetHead(&sloc->usl.itmpStack,sym);
458 /* could not then have to create one , this is the hard part
459 we need to allocate this on the stack : this is really a
460 hack!! but cannot think of anything better at this time */
462 if (sprintf(slocBuffer,"sloc%d",_G.slocNum++) >= sizeof(slocBuffer))
464 fprintf(stderr, "***Internal error: slocBuffer overflowed: %s:%d\n",
469 sloc = newiTemp(slocBuffer);
471 /* set the type to the spilling symbol */
472 sloc->type = copyLinkChain(sym->type);
473 sloc->etype = getSpec(sloc->type);
474 SPEC_SCLS(sloc->etype) = S_DATA ;
475 SPEC_EXTR(sloc->etype) = 0;
477 /* we don't allow it to be allocated`
478 onto the external stack since : so we
479 temporarily turn it off ; we also
480 turn off memory model to prevent
481 the spil from going to the external storage
482 and turn off overlaying
485 useXstack = options.useXstack;
486 model = options.model;
487 noOverlay = options.noOverlay;
488 options.noOverlay = 1;
489 options.model = options.useXstack = 0;
493 options.useXstack = useXstack;
494 options.model = model;
495 options.noOverlay = noOverlay;
496 sloc->isref = 1; /* to prevent compiler warning */
498 /* if it is on the stack then update the stack */
499 if (IN_STACK(sloc->etype)) {
500 currFunc->stack += getSize(sloc->type);
501 _G.stackExtend += getSize(sloc->type);
503 _G.dataExtend += getSize(sloc->type);
505 /* add it to the _G.stackSpil set */
506 addSetHead(&_G.stackSpil,sloc);
507 sym->usl.spillLoc = sloc;
510 /* add it to the set of itempStack set
511 of the spill location */
512 addSetHead(&sloc->usl.itmpStack,sym);
516 /*-----------------------------------------------------------------*/
517 /* isSpiltOnStack - returns true if the spil location is on stack */
518 /*-----------------------------------------------------------------*/
519 static bool isSpiltOnStack (symbol *sym)
529 /* if (sym->_G.stackSpil) */
532 if (!sym->usl.spillLoc)
535 etype = getSpec(sym->usl.spillLoc->type);
542 /*-----------------------------------------------------------------*/
543 /* spillThis - spils a specific operand */
544 /*-----------------------------------------------------------------*/
545 static void spillThis (symbol *sym)
548 /* if this is rematerializable or has a spillLocation
549 we are okay, else we need to create a spillLocation
551 if (!(sym->remat || sym->usl.spillLoc))
552 createStackSpil (sym);
555 /* mark it has spilt & put it in the spilt set */
557 _G.spiltSet = bitVectSetBit(_G.spiltSet,sym->key);
559 bitVectUnSetBit(_G.regAssigned,sym->key);
561 for (i = 0 ; i < sym->nRegs ; i++)
564 freeReg(sym->regs[i]);
568 /* if spilt on stack then free up r0 & r1
569 if they could have been assigned to some
571 if (!mcs51_ptrRegReq && isSpiltOnStack(sym)) {
573 spillLRWithPtrReg(sym);
576 if (sym->usl.spillLoc && !sym->remat)
577 sym->usl.spillLoc->allocreq = 1;
581 /*-----------------------------------------------------------------*/
582 /* selectSpil - select a iTemp to spil : rather a simple procedure */
583 /*-----------------------------------------------------------------*/
584 static symbol *selectSpil (iCode *ic, eBBlock *ebp, symbol *forSym)
586 bitVect *lrcs= NULL ;
590 /* get the spillable live ranges */
591 lrcs = computeSpillable (ic);
593 /* get all live ranges that are rematerizable */
594 if ((selectS = liveRangesWith(lrcs,rematable,ebp,ic))) {
596 /* return the least used of these */
597 return leastUsedLR(selectS);
600 /* get live ranges with spillLocations in direct space */
601 if ((selectS = liveRangesWith(lrcs,directSpilLoc,ebp,ic))) {
602 sym = leastUsedLR(selectS);
603 strcpy(sym->rname,(sym->usl.spillLoc->rname[0] ?
604 sym->usl.spillLoc->rname :
605 sym->usl.spillLoc->name));
607 /* mark it as allocation required */
608 sym->usl.spillLoc->allocreq = 1;
612 /* if the symbol is local to the block then */
613 if (forSym->liveTo < ebp->lSeq ) {
615 /* check if there are any live ranges allocated
616 to registers that are not used in this block */
617 if (!_G.blockSpil && (selectS = liveRangesWith(lrcs,notUsedInBlock,ebp,ic))) {
618 sym = leastUsedLR(selectS);
619 /* if this is not rematerializable */
627 /* check if there are any live ranges that not
628 used in the remainder of the block */
629 if (!_G.blockSpil && (selectS = liveRangesWith(lrcs,notUsedInRemaining,ebp,ic))) {
630 sym = leastUsedLR (selectS);
639 /* find live ranges with spillocation && not used as pointers */
640 if ((selectS = liveRangesWith(lrcs,hasSpilLocnoUptr,ebp,ic))) {
642 sym = leastUsedLR(selectS);
643 /* mark this as allocation required */
644 sym->usl.spillLoc->allocreq = 1;
648 /* find live ranges with spillocation */
649 if ((selectS = liveRangesWith(lrcs,hasSpilLoc,ebp,ic))) {
651 sym = leastUsedLR(selectS);
652 sym->usl.spillLoc->allocreq = 1;
656 /* couldn't find then we need to create a spil
657 location on the stack , for which one? the least
659 if ((selectS = liveRangesWith(lrcs,noSpilLoc,ebp,ic))) {
661 /* return a created spil location */
662 sym = createStackSpil(leastUsedLR(selectS));
663 sym->usl.spillLoc->allocreq = 1;
667 /* this is an extreme situation we will spill
668 this one : happens very rarely but it does happen */
669 spillThis ( forSym );
674 /*-----------------------------------------------------------------*/
675 /* spilSomething - spil some variable & mark registers as free */
676 /*-----------------------------------------------------------------*/
677 static bool spilSomething (iCode *ic, eBBlock *ebp, symbol *forSym)
682 /* get something we can spil */
683 ssym = selectSpil(ic,ebp,forSym);
685 /* mark it as spilt */
687 _G.spiltSet = bitVectSetBit(_G.spiltSet,ssym->key);
689 /* mark it as not register assigned &
690 take it away from the set */
691 bitVectUnSetBit(_G.regAssigned,ssym->key);
693 /* mark the registers as free */
694 for (i = 0 ; i < ssym->nRegs ;i++ )
696 freeReg(ssym->regs[i]);
698 /* if spilt on stack then free up r0 & r1
699 if they could have been assigned to as gprs */
700 if (!mcs51_ptrRegReq && isSpiltOnStack(ssym) ) {
702 spillLRWithPtrReg(ssym);
705 /* if this was a block level spil then insert push & pop
706 at the start & end of block respectively */
707 if (ssym->blockSpil) {
708 iCode *nic = newiCode(IPUSH,operandFromSymbol(ssym),NULL);
709 /* add push to the start of the block */
710 addiCodeToeBBlock(ebp,nic,( ebp->sch->op == LABEL ?
711 ebp->sch->next : ebp->sch));
712 nic = newiCode(IPOP,operandFromSymbol(ssym),NULL);
713 /* add pop to the end of the block */
714 addiCodeToeBBlock(ebp,nic,NULL);
717 /* if spilt because not used in the remainder of the
718 block then add a push before this instruction and
719 a pop at the end of the block */
720 if (ssym->remainSpil) {
722 iCode *nic = newiCode(IPUSH,operandFromSymbol(ssym),NULL);
723 /* add push just before this instruction */
724 addiCodeToeBBlock(ebp,nic,ic);
726 nic = newiCode(IPOP,operandFromSymbol(ssym),NULL);
727 /* add pop to the end of the block */
728 addiCodeToeBBlock(ebp,nic,NULL);
737 /*-----------------------------------------------------------------*/
738 /* getRegPtr - will try for PTR if not a GPR type if not spil */
739 /*-----------------------------------------------------------------*/
740 regs *getRegPtr (iCode *ic, eBBlock *ebp, symbol *sym)
745 /* try for a ptr type */
746 if ((reg = allocReg(REG_PTR)))
749 /* try for gpr type */
750 if ((reg = allocReg(REG_GPR)))
753 /* we have to spil */
754 if (!spilSomething (ic,ebp,sym))
757 /* this looks like an infinite loop but
758 in really selectSpil will abort */
762 /*-----------------------------------------------------------------*/
763 /* getRegGpr - will try for GPR if not spil */
764 /*-----------------------------------------------------------------*/
765 static regs *getRegGpr (iCode *ic, eBBlock *ebp,symbol *sym)
770 /* try for gpr type */
771 if ((reg = allocReg(REG_GPR)))
774 if (!mcs51_ptrRegReq)
775 if ((reg = allocReg(REG_PTR)))
778 /* we have to spil */
779 if (!spilSomething (ic,ebp,sym))
782 /* this looks like an infinite loop but
783 in really selectSpil will abort */
787 /*-----------------------------------------------------------------*/
788 /* symHasReg - symbol has a given register */
789 /*-----------------------------------------------------------------*/
790 static bool symHasReg(symbol *sym,regs *reg)
794 for ( i = 0 ; i < sym->nRegs ; i++)
795 if (sym->regs[i] == reg)
801 /*-----------------------------------------------------------------*/
802 /* deassignLRs - check the live to and if they have registers & are*/
803 /* not spilt then free up the registers */
804 /*-----------------------------------------------------------------*/
805 static void deassignLRs (iCode *ic, eBBlock *ebp)
811 for (sym = hTabFirstItem(liveRanges,&k); sym;
812 sym = hTabNextItem(liveRanges,&k)) {
815 /* if it does not end here */
816 if (sym->liveTo > ic->seq )
819 /* if it was spilt on stack then we can
820 mark the stack spil location as free */
822 if (sym->stackSpil) {
823 sym->usl.spillLoc->isFree = 1;
829 if (!bitVectBitValue(_G.regAssigned,sym->key))
832 /* special case check if this is an IFX &
833 the privious one was a pop and the
834 previous one was not spilt then keep track
836 if (ic->op == IFX && ic->prev &&
837 ic->prev->op == IPOP &&
838 !ic->prev->parmPush &&
839 !OP_SYMBOL(IC_LEFT(ic->prev))->isspilt)
840 psym = OP_SYMBOL(IC_LEFT(ic->prev));
845 bitVectUnSetBit(_G.regAssigned,sym->key);
847 /* if the result of this one needs registers
848 and does not have it then assign it right
851 ! (SKIP_IC2(ic) || /* not a special icode */
852 ic->op == JUMPTABLE ||
858 (result = OP_SYMBOL(IC_RESULT(ic))) && /* has a result */
859 result->liveTo > ic->seq && /* and will live beyond this */
860 result->liveTo <= ebp->lSeq && /* does not go beyond this block */
861 result->regType == sym->regType && /* same register types */
862 result->nRegs && /* which needs registers */
863 ! result->isspilt && /* and does not already have them */
865 ! bitVectBitValue(_G.regAssigned,result->key) &&
866 /* the number of free regs + number of regs in this LR
867 can accomodate the what result Needs */
868 ((nfreeRegsType(result->regType) +
869 sym->nRegs) >= result->nRegs)
872 for (i = 0 ; i < max(sym->nRegs,result->nRegs) ; i++)
874 result->regs[i] = sym->regs[i] ;
876 result->regs[i] = getRegGpr (ic,ebp,result);
878 _G.regAssigned = bitVectSetBit(_G.regAssigned,result->key);
882 /* free the remaining */
883 for (; i < sym->nRegs ; i++) {
885 if (!symHasReg(psym,sym->regs[i]))
886 freeReg(sym->regs[i]);
888 freeReg(sym->regs[i]);
895 /*-----------------------------------------------------------------*/
896 /* reassignLR - reassign this to registers */
897 /*-----------------------------------------------------------------*/
898 static void reassignLR (operand *op)
900 symbol *sym = OP_SYMBOL(op);
903 /* not spilt any more */
904 sym->isspilt = sym->blockSpil = sym->remainSpil = 0;
905 bitVectUnSetBit(_G.spiltSet,sym->key);
907 _G.regAssigned = bitVectSetBit(_G.regAssigned,sym->key);
911 for (i=0;i<sym->nRegs;i++)
912 sym->regs[i]->isFree = 0;
915 /*-----------------------------------------------------------------*/
916 /* willCauseSpill - determines if allocating will cause a spill */
917 /*-----------------------------------------------------------------*/
918 static int willCauseSpill ( int nr, int rt)
920 /* first check if there are any avlb registers
921 of te type required */
923 /* special case for pointer type
924 if pointer type not avlb then
925 check for type gpr */
926 if (nFreeRegs(rt) >= nr)
928 if (nFreeRegs(REG_GPR) >= nr)
931 if (mcs51_ptrRegReq) {
932 if (nFreeRegs(rt) >= nr)
935 if (nFreeRegs(REG_PTR) +
936 nFreeRegs(REG_GPR) >= nr)
941 /* it will cause a spil */
945 /*-----------------------------------------------------------------*/
946 /* positionRegs - the allocator can allocate same registers to res-*/
947 /* ult and operand, if this happens make sure they are in the same */
948 /* position as the operand otherwise chaos results */
949 /*-----------------------------------------------------------------*/
950 static void positionRegs (symbol *result, symbol *opsym, int lineno)
952 int count = min(result->nRegs,opsym->nRegs);
953 int i , j = 0, shared = 0;
955 /* if the result has been spilt then cannot share */
960 /* first make sure that they actually share */
961 for ( i = 0 ; i < count; i++ ) {
962 for (j = 0 ; j < count ; j++ ) {
963 if (result->regs[i] == opsym->regs[j] && i !=j) {
971 regs *tmp = result->regs[i];
972 result->regs[i] = result->regs[j];
973 result->regs[j] = tmp;
978 /*-----------------------------------------------------------------*/
979 /* serialRegAssign - serially allocate registers to the variables */
980 /*-----------------------------------------------------------------*/
981 static void serialRegAssign (eBBlock **ebbs, int count)
986 for (i = 0; i < count ; i++ ) {
990 if (ebbs[i]->noPath &&
991 (ebbs[i]->entryLabel != entryLabel &&
992 ebbs[i]->entryLabel != returnLabel ))
995 /* of all instructions do */
996 for (ic = ebbs[i]->sch ; ic ; ic = ic->next) {
998 /* if this is an ipop that means some live
999 range will have to be assigned again */
1001 reassignLR (IC_LEFT(ic));
1003 /* if result is present && is a true symbol */
1004 if (IC_RESULT(ic) && ic->op != IFX &&
1005 IS_TRUE_SYMOP(IC_RESULT(ic)))
1006 OP_SYMBOL(IC_RESULT(ic))->allocreq = 1;
1008 /* take away registers from live
1009 ranges that end at this instruction */
1010 deassignLRs (ic, ebbs[i]) ;
1012 /* some don't need registers */
1014 ic->op == JUMPTABLE ||
1018 (IC_RESULT(ic) &&POINTER_SET(ic)) )
1021 /* now we need to allocate registers
1022 only for the result */
1023 if (IC_RESULT(ic)) {
1024 symbol *sym = OP_SYMBOL(IC_RESULT(ic));
1030 /* if it does not need or is spilt
1031 or is already assigned to registers
1032 or will not live beyond this instructions */
1035 bitVectBitValue(_G.regAssigned,sym->key) ||
1036 sym->liveTo <= ic->seq)
1039 /* if some liverange has been spilt at the block level
1040 and this one live beyond this block then spil this
1042 if (_G.blockSpil && sym->liveTo > ebbs[i]->lSeq) {
1046 /* if trying to allocate this will cause
1047 a spill and there is nothing to spill
1048 or this one is rematerializable then
1050 willCS = willCauseSpill(sym->nRegs,sym->regType);
1051 spillable = computeSpillable(ic);
1053 (willCS && bitVectIsZero(spillable) ) ) {
1060 /* if it has a spillocation & is used less than
1061 all other live ranges then spill this */
1062 if ( willCS && sym->usl.spillLoc ) {
1065 leastUsedLR(liveRangesWith (spillable ,
1070 leastUsed->used > sym->used) {
1076 /* if we need ptr regs for the right side
1078 if (POINTER_GET(ic) && getSize(OP_SYMBOL(IC_LEFT(ic))->type)
1084 /* else we assign registers to it */
1085 _G.regAssigned = bitVectSetBit(_G.regAssigned,sym->key);
1087 for (j = 0 ; j < sym->nRegs ;j++ ) {
1088 if (sym->regType == REG_PTR)
1089 sym->regs[j] = getRegPtr(ic,ebbs[i],sym);
1091 sym->regs[j] = getRegGpr(ic,ebbs[i],sym);
1093 /* if the allocation falied which means
1094 this was spilt then break */
1098 /* if it shares registers with operands make sure
1099 that they are in the same position */
1100 if (IC_LEFT(ic) && IS_SYMOP(IC_LEFT(ic)) &&
1101 OP_SYMBOL(IC_LEFT(ic))->nRegs && ic->op != '=')
1102 positionRegs(OP_SYMBOL(IC_RESULT(ic)),
1103 OP_SYMBOL(IC_LEFT(ic)),ic->lineno);
1104 /* do the same for the right operand */
1105 if (IC_RIGHT(ic) && IS_SYMOP(IC_RIGHT(ic)) &&
1106 OP_SYMBOL(IC_RIGHT(ic))->nRegs && ic->op != '=')
1107 positionRegs(OP_SYMBOL(IC_RESULT(ic)),
1108 OP_SYMBOL(IC_RIGHT(ic)),ic->lineno);
1120 /*-----------------------------------------------------------------*/
1121 /* rUmaskForOp :- returns register mask for an operand */
1122 /*-----------------------------------------------------------------*/
1123 static bitVect *rUmaskForOp (operand *op)
1129 /* only temporaries are assigned registers */
1133 sym = OP_SYMBOL(op);
1135 /* if spilt or no registers assigned to it
1137 if (sym->isspilt || !sym->nRegs)
1140 rumask = newBitVect(mcs51_nRegs);
1142 for (j = 0; j < sym->nRegs; j++) {
1143 rumask = bitVectSetBit(rumask,
1144 sym->regs[j]->rIdx);
1150 /*-----------------------------------------------------------------*/
1151 /* regsUsedIniCode :- returns bit vector of registers used in iCode*/
1152 /*-----------------------------------------------------------------*/
1153 static bitVect *regsUsedIniCode (iCode *ic)
1155 bitVect *rmask = newBitVect(mcs51_nRegs);
1157 /* do the special cases first */
1158 if (ic->op == IFX ) {
1159 rmask = bitVectUnion(rmask,
1160 rUmaskForOp(IC_COND(ic)));
1164 /* for the jumptable */
1165 if (ic->op == JUMPTABLE) {
1166 rmask = bitVectUnion(rmask,
1167 rUmaskForOp(IC_JTCOND(ic)));
1172 /* of all other cases */
1174 rmask = bitVectUnion(rmask,
1175 rUmaskForOp(IC_LEFT(ic)));
1179 rmask = bitVectUnion(rmask,
1180 rUmaskForOp(IC_RIGHT(ic)));
1183 rmask = bitVectUnion(rmask,
1184 rUmaskForOp(IC_RESULT(ic)));
1190 /*-----------------------------------------------------------------*/
1191 /* createRegMask - for each instruction will determine the regsUsed*/
1192 /*-----------------------------------------------------------------*/
1193 static void createRegMask (eBBlock **ebbs, int count)
1197 /* for all blocks */
1198 for (i = 0; i < count ; i++ ) {
1201 if ( ebbs[i]->noPath &&
1202 ( ebbs[i]->entryLabel != entryLabel &&
1203 ebbs[i]->entryLabel != returnLabel ))
1206 /* for all instructions */
1207 for ( ic = ebbs[i]->sch ; ic ; ic = ic->next ) {
1211 if (SKIP_IC2(ic) || !ic->rlive)
1214 /* first mark the registers used in this
1216 ic->rUsed = regsUsedIniCode(ic);
1217 _G.funcrUsed = bitVectUnion(_G.funcrUsed,ic->rUsed);
1219 /* now create the register mask for those
1220 registers that are in use : this is a
1221 super set of ic->rUsed */
1222 ic->rMask = newBitVect(mcs51_nRegs+1);
1224 /* for all live Ranges alive at this point */
1225 for (j = 1; j < ic->rlive->size; j++ ) {
1229 /* if not alive then continue */
1230 if (!bitVectBitValue(ic->rlive,j))
1233 /* find the live range we are interested in */
1234 if (!(sym = hTabItemWithKey(liveRanges,j))) {
1235 werror (E_INTERNAL_ERROR,__FILE__,__LINE__,
1236 "createRegMask cannot find live range");
1240 /* if no register assigned to it */
1241 if (!sym->nRegs || sym->isspilt)
1244 /* for all the registers allocated to it */
1245 for (k = 0 ; k < sym->nRegs ;k++)
1248 bitVectSetBit(ic->rMask,sym->regs[k]->rIdx);
1254 /*-----------------------------------------------------------------*/
1255 /* rematStr - returns the rematerialized string for a remat var */
1256 /*-----------------------------------------------------------------*/
1257 static char *rematStr (symbol *sym)
1260 iCode *ic = sym->rematiCode;
1264 /* if plus or minus print the right hand side */
1265 if (ic->op == '+' || ic->op == '-') {
1266 sprintf(s,"0x%04x %c ",(int) operandLitValue(IC_RIGHT(ic)),
1269 ic = OP_SYMBOL(IC_LEFT(ic))->rematiCode;
1273 /* we reached the end */
1274 sprintf(s,"%s",OP_SYMBOL(IC_LEFT(ic))->rname);
1281 /*-----------------------------------------------------------------*/
1282 /* regTypeNum - computes the type & number of registers required */
1283 /*-----------------------------------------------------------------*/
1284 static void regTypeNum ()
1290 /* for each live range do */
1291 for ( sym = hTabFirstItem(liveRanges,&k); sym ;
1292 sym = hTabNextItem(liveRanges,&k)) {
1294 /* if used zero times then no registers needed */
1295 if ((sym->liveTo - sym->liveFrom) == 0)
1299 /* if the live range is a temporary */
1302 /* if the type is marked as a conditional */
1303 if (sym->regType == REG_CND)
1306 /* if used in return only then we don't
1308 if (sym->ruonly || sym->accuse) {
1309 if (IS_AGGREGATE(sym->type) || sym->isptr)
1310 sym->type = aggrToPtr(sym->type,FALSE);
1314 /* if the symbol has only one definition &
1315 that definition is a get_pointer and the
1316 pointer we are getting is rematerializable and
1319 if (bitVectnBitsOn(sym->defs) == 1 &&
1320 (ic = hTabItemWithKey(iCodehTab,
1321 bitVectFirstBit(sym->defs))) &&
1323 !IS_BITVAR(sym->etype)) {
1326 /* if remat in data space */
1327 if (OP_SYMBOL(IC_LEFT(ic))->remat &&
1328 DCL_TYPE(aggrToPtr(sym->type,FALSE)) == POINTER) {
1330 /* create a psuedo symbol & force a spil */
1331 symbol *psym = newSymbol(rematStr(OP_SYMBOL(IC_LEFT(ic))),1);
1332 psym->type = sym->type;
1333 psym->etype = sym->etype;
1334 strcpy(psym->rname,psym->name);
1336 sym->usl.spillLoc = psym;
1340 /* if in data space or idata space then try to
1341 allocate pointer register */
1345 /* if not then we require registers */
1346 sym->nRegs = ((IS_AGGREGATE(sym->type) || sym->isptr ) ?
1347 getSize(sym->type = aggrToPtr(sym->type,FALSE)) :
1348 getSize(sym->type));
1350 if (sym->nRegs > 4) {
1351 fprintf(stderr,"allocated more than 4 or 0 registers for type ");
1352 printTypeChain(sym->type,stderr);fprintf(stderr,"\n");
1355 /* determine the type of register required */
1356 if (sym->nRegs == 1 &&
1357 IS_PTR(sym->type) &&
1359 sym->regType = REG_PTR ;
1361 sym->regType = REG_GPR ;
1364 /* for the first run we don't provide */
1365 /* registers for true symbols we will */
1366 /* see how things go */
1372 /*-----------------------------------------------------------------*/
1373 /* freeAllRegs - mark all registers as free */
1374 /*-----------------------------------------------------------------*/
1375 static void freeAllRegs()
1379 for (i=0;i< mcs51_nRegs;i++ )
1380 regs8051[i].isFree = 1;
1383 /*-----------------------------------------------------------------*/
1384 /* deallocStackSpil - this will set the stack pointer back */
1385 /*-----------------------------------------------------------------*/
1386 static DEFSETFUNC(deallocStackSpil)
1394 /*-----------------------------------------------------------------*/
1395 /* farSpacePackable - returns the packable icode for far variables */
1396 /*-----------------------------------------------------------------*/
1397 static iCode *farSpacePackable (iCode *ic)
1401 /* go thru till we find a definition for the
1402 symbol on the right */
1403 for ( dic = ic->prev ; dic ; dic = dic->prev) {
1405 /* if the definition is a call then no */
1406 if ((dic->op == CALL || dic->op == PCALL) &&
1407 IC_RESULT(dic)->key == IC_RIGHT(ic)->key) {
1411 /* if shift by unknown amount then not */
1412 if ((dic->op == LEFT_OP || dic->op == RIGHT_OP) &&
1413 IC_RESULT(dic)->key == IC_RIGHT(ic)->key)
1416 /* if pointer get and size > 1 */
1417 if (POINTER_GET(dic) &&
1418 getSize(aggrToPtr(operandType(IC_LEFT(dic)),FALSE)) > 1)
1421 if (POINTER_SET(dic) &&
1422 getSize(aggrToPtr(operandType(IC_RESULT(dic)),FALSE)) > 1)
1425 /* if any three is a true symbol in far space */
1426 if (IC_RESULT(dic) &&
1427 IS_TRUE_SYMOP(IC_RESULT(dic)) &&
1428 isOperandInFarSpace(IC_RESULT(dic)))
1431 if (IC_RIGHT(dic) &&
1432 IS_TRUE_SYMOP(IC_RIGHT(dic)) &&
1433 isOperandInFarSpace(IC_RIGHT(dic)) &&
1434 !isOperandEqual(IC_RIGHT(dic),IC_RESULT(ic)))
1438 IS_TRUE_SYMOP(IC_LEFT(dic)) &&
1439 isOperandInFarSpace(IC_LEFT(dic)) &&
1440 !isOperandEqual(IC_LEFT(dic),IC_RESULT(ic)))
1443 if (isOperandEqual(IC_RIGHT(ic),IC_RESULT(dic))) {
1444 if ( (dic->op == LEFT_OP ||
1445 dic->op == RIGHT_OP ||
1447 IS_OP_LITERAL(IC_RIGHT(dic)))
1457 /*-----------------------------------------------------------------*/
1458 /* packRegsForAssign - register reduction for assignment */
1459 /*-----------------------------------------------------------------*/
1460 static int packRegsForAssign (iCode *ic,eBBlock *ebp)
1464 if (!IS_ITEMP(IC_RIGHT(ic)) ||
1465 OP_SYMBOL(IC_RIGHT(ic))->isind ||
1466 OP_LIVETO(IC_RIGHT(ic)) > ic->seq) {
1470 /* if the true symbol is defined in far space or on stack
1471 then we should not since this will increase register pressure */
1472 if (isOperandInFarSpace(IC_RESULT(ic))) {
1473 if ((dic = farSpacePackable(ic)))
1479 /* find the definition of iTempNN scanning backwards if we find a
1480 a use of the true symbol in before we find the definition then
1482 for ( dic = ic->prev ; dic ; dic = dic->prev) {
1484 /* if there is a function call and this is
1485 a parameter & not my parameter then don't pack it */
1486 if ( (dic->op == CALL || dic->op == PCALL) &&
1487 (OP_SYMBOL(IC_RESULT(ic))->_isparm &&
1488 !OP_SYMBOL(IC_RESULT(ic))->ismyparm)) {
1496 if (IS_TRUE_SYMOP(IC_RESULT(dic)) &&
1497 IS_OP_VOLATILE(IC_RESULT(dic))) {
1502 if (IS_SYMOP(IC_RESULT(dic)) &&
1503 IC_RESULT(dic)->key == IC_RIGHT(ic)->key) {
1504 if (POINTER_SET(dic))
1510 if (IS_SYMOP(IC_RIGHT(dic)) &&
1511 (IC_RIGHT(dic)->key == IC_RESULT(ic)->key ||
1512 IC_RIGHT(dic)->key == IC_RIGHT(ic)->key)) {
1517 if (IS_SYMOP(IC_LEFT(dic)) &&
1518 (IC_LEFT(dic)->key == IC_RESULT(ic)->key ||
1519 IC_LEFT(dic)->key == IC_RIGHT(ic)->key)) {
1524 if (POINTER_SET(dic) &&
1525 IC_RESULT(dic)->key == IC_RESULT(ic)->key ) {
1532 return 0 ; /* did not find */
1534 /* if the result is on stack or iaccess then it must be
1535 the same atleast one of the operands */
1536 if (OP_SYMBOL(IC_RESULT(ic))->onStack ||
1537 OP_SYMBOL(IC_RESULT(ic))->iaccess ) {
1539 /* the operation has only one symbol
1540 operator then we can pack */
1541 if ((IC_LEFT(dic) && !IS_SYMOP(IC_LEFT(dic))) ||
1542 (IC_RIGHT(dic) && !IS_SYMOP(IC_RIGHT(dic))))
1545 if (!((IC_LEFT(dic) &&
1546 IC_RESULT(ic)->key == IC_LEFT(dic)->key) ||
1548 IC_RESULT(ic)->key == IC_RIGHT(dic)->key)))
1552 /* found the definition */
1553 /* replace the result with the result of */
1554 /* this assignment and remove this assignment */
1555 IC_RESULT(dic) = IC_RESULT(ic) ;
1557 if (IS_ITEMP(IC_RESULT(dic)) && OP_SYMBOL(IC_RESULT(dic))->liveFrom > dic->seq) {
1558 OP_SYMBOL(IC_RESULT(dic))->liveFrom = dic->seq;
1560 /* delete from liverange table also
1561 delete from all the points inbetween and the new
1563 for ( sic = dic; sic != ic ; sic = sic->next ) {
1564 bitVectUnSetBit(sic->rlive,IC_RESULT(ic)->key);
1565 if (IS_ITEMP(IC_RESULT(dic)))
1566 bitVectSetBit(sic->rlive,IC_RESULT(dic)->key);
1569 remiCodeFromeBBlock(ebp,ic);
1570 hTabDeleteItem (&iCodehTab,ic->key,ic,DELETE_ITEM,NULL);
1575 /*-----------------------------------------------------------------*/
1576 /* findAssignToSym : scanning backwards looks for first assig found*/
1577 /*-----------------------------------------------------------------*/
1578 static iCode *findAssignToSym (operand *op,iCode *ic)
1582 for (dic = ic->prev ; dic ; dic = dic->prev) {
1584 /* if definition by assignment */
1585 if (dic->op == '=' &&
1586 !POINTER_SET(dic) &&
1587 IC_RESULT(dic)->key == op->key
1588 /* && IS_TRUE_SYMOP(IC_RIGHT(dic)) */
1591 /* we are interested only if defined in far space */
1592 /* or in stack space in case of + & - */
1594 /* if assigned to a non-symbol then return
1596 if (!IS_SYMOP(IC_RIGHT(dic)))
1599 /* if the symbol is in far space then
1601 if (isOperandInFarSpace(IC_RIGHT(dic)))
1604 /* for + & - operations make sure that
1605 if it is on the stack it is the same
1606 as one of the three operands */
1607 if ((ic->op == '+' || ic->op == '-') &&
1608 OP_SYMBOL(IC_RIGHT(dic))->onStack) {
1610 if ( IC_RESULT(ic)->key != IC_RIGHT(dic)->key &&
1611 IC_LEFT(ic)->key != IC_RIGHT(dic)->key &&
1612 IC_RIGHT(ic)->key != IC_RIGHT(dic)->key)
1620 /* if we find an usage then we cannot delete it */
1621 if (IC_LEFT(dic) && IC_LEFT(dic)->key == op->key)
1624 if (IC_RIGHT(dic) && IC_RIGHT(dic)->key == op->key)
1627 if (POINTER_SET(dic) && IC_RESULT(dic)->key == op->key)
1631 /* now make sure that the right side of dic
1632 is not defined between ic & dic */
1634 iCode *sic = dic->next ;
1636 for (; sic != ic ; sic = sic->next)
1637 if (IC_RESULT(sic) &&
1638 IC_RESULT(sic)->key == IC_RIGHT(dic)->key)
1647 /*-----------------------------------------------------------------*/
1648 /* packRegsForSupport :- reduce some registers for support calls */
1649 /*-----------------------------------------------------------------*/
1650 static int packRegsForSupport (iCode *ic, eBBlock *ebp)
1653 /* for the left & right operand :- look to see if the
1654 left was assigned a true symbol in far space in that
1655 case replace them */
1656 if (IS_ITEMP(IC_LEFT(ic)) &&
1657 OP_SYMBOL(IC_LEFT(ic))->liveTo <= ic->seq) {
1658 iCode *dic = findAssignToSym(IC_LEFT(ic),ic);
1664 /* found it we need to remove it from the
1666 for ( sic = dic; sic != ic ; sic = sic->next )
1667 bitVectUnSetBit(sic->rlive,IC_LEFT(ic)->key);
1669 IC_LEFT(ic)->operand.symOperand =
1670 IC_RIGHT(dic)->operand.symOperand;
1671 IC_LEFT(ic)->key = IC_RIGHT(dic)->operand.symOperand->key;
1672 remiCodeFromeBBlock(ebp,dic);
1673 hTabDeleteItem (&iCodehTab,dic->key,dic,DELETE_ITEM,NULL);
1677 /* do the same for the right operand */
1680 IS_ITEMP(IC_RIGHT(ic)) &&
1681 OP_SYMBOL(IC_RIGHT(ic))->liveTo <= ic->seq) {
1682 iCode *dic = findAssignToSym(IC_RIGHT(ic),ic);
1688 /* if this is a subtraction & the result
1689 is a true symbol in far space then don't pack */
1690 if (ic->op == '-' && IS_TRUE_SYMOP(IC_RESULT(dic))) {
1691 link *etype =getSpec(operandType(IC_RESULT(dic)));
1692 if (IN_FARSPACE(SPEC_OCLS(etype)))
1695 /* found it we need to remove it from the
1697 for ( sic = dic; sic != ic ; sic = sic->next )
1698 bitVectUnSetBit(sic->rlive,IC_RIGHT(ic)->key);
1700 IC_RIGHT(ic)->operand.symOperand =
1701 IC_RIGHT(dic)->operand.symOperand;
1702 IC_RIGHT(ic)->key = IC_RIGHT(dic)->operand.symOperand->key;
1704 remiCodeFromeBBlock(ebp,dic);
1705 hTabDeleteItem (&iCodehTab,dic->key,dic,DELETE_ITEM,NULL);
1712 #define IS_OP_RUONLY(x) (x && IS_SYMOP(x) && OP_SYMBOL(x)->ruonly)
1715 /*-----------------------------------------------------------------*/
1716 /* packRegsForOneuse : - will reduce some registers for single Use */
1717 /*-----------------------------------------------------------------*/
1718 static iCode *packRegsForOneuse (iCode *ic, operand *op , eBBlock *ebp)
1723 /* if returning a literal then do nothing */
1727 /* only upto 2 bytes since we cannot predict
1728 the usage of b, & acc */
1729 if (getSize(operandType(op)) > (fReturnSize - 2) &&
1734 /* this routine will mark the a symbol as used in one
1735 instruction use only && if the defintion is local
1736 (ie. within the basic block) && has only one definition &&
1737 that definiion is either a return value from a
1738 function or does not contain any variables in
1740 uses = bitVectCopy(OP_USES(op));
1741 bitVectUnSetBit(uses,ic->key); /* take away this iCode */
1742 if (!bitVectIsZero(uses)) /* has other uses */
1745 /* if it has only one defintion */
1746 if (bitVectnBitsOn(OP_DEFS(op)) > 1)
1747 return NULL ; /* has more than one definition */
1749 /* get the that definition */
1751 hTabItemWithKey(iCodehTab,
1752 bitVectFirstBit(OP_DEFS(op)))))
1755 /* found the definition now check if it is local */
1756 if (dic->seq < ebp->fSeq ||
1757 dic->seq > ebp->lSeq)
1758 return NULL ; /* non-local */
1760 /* now check if it is the return from
1762 if (dic->op == CALL || dic->op == PCALL ) {
1763 if (ic->op != SEND && ic->op != RETURN) {
1764 OP_SYMBOL(op)->ruonly = 1;
1771 /* otherwise check that the definition does
1772 not contain any symbols in far space */
1773 if (isOperandInFarSpace(IC_LEFT(dic)) ||
1774 isOperandInFarSpace(IC_RIGHT(dic)) ||
1775 IS_OP_RUONLY(IC_LEFT(ic)) ||
1776 IS_OP_RUONLY(IC_RIGHT(ic)) ) {
1780 /* if pointer set then make sure the pointer
1782 if (POINTER_SET(dic) &&
1783 !IS_DATA_PTR(aggrToPtr(operandType(IC_RESULT(dic)),FALSE)))
1786 if (POINTER_GET(dic) &&
1787 !IS_DATA_PTR(aggrToPtr(operandType(IC_LEFT(dic)),FALSE)))
1792 /* also make sure the intervenening instructions
1793 don't have any thing in far space */
1794 for (dic = dic->next ; dic && dic != ic ; dic = dic->next) {
1796 /* if there is an intervening function call then no */
1797 if (dic->op == CALL || dic->op == PCALL)
1799 /* if pointer set then make sure the pointer
1801 if (POINTER_SET(dic) &&
1802 !IS_DATA_PTR(aggrToPtr(operandType(IC_RESULT(dic)),FALSE)))
1805 if (POINTER_GET(dic) &&
1806 !IS_DATA_PTR(aggrToPtr(operandType(IC_LEFT(dic)),FALSE)))
1809 /* if address of & the result is remat the okay */
1810 if (dic->op == ADDRESS_OF &&
1811 OP_SYMBOL(IC_RESULT(dic))->remat)
1814 /* if operand has size of three or more & this
1815 operation is a '*','/' or '%' then 'b' may
1817 if (( dic->op == '%' || dic->op == '/' || dic->op == '*') &&
1818 getSize(operandType(op)) >= 3)
1821 /* if left or right or result is in far space */
1822 if (isOperandInFarSpace(IC_LEFT(dic)) ||
1823 isOperandInFarSpace(IC_RIGHT(dic)) ||
1824 isOperandInFarSpace(IC_RESULT(dic)) ||
1825 IS_OP_RUONLY(IC_LEFT(dic)) ||
1826 IS_OP_RUONLY(IC_RIGHT(dic)) ||
1827 IS_OP_RUONLY(IC_RESULT(dic)) ) {
1832 OP_SYMBOL(op)->ruonly = 1;
1837 /*-----------------------------------------------------------------*/
1838 /* isBitwiseOptimizable - requirements of JEAN LOUIS VERN */
1839 /*-----------------------------------------------------------------*/
1840 static bool isBitwiseOptimizable (iCode *ic)
1842 link *ltype = getSpec(operandType(IC_LEFT(ic)));
1843 link *rtype = getSpec(operandType(IC_RIGHT(ic)));
1845 /* bitwise operations are considered optimizable
1846 under the following conditions (Jean-Louis VERN)
1858 if ( IS_LITERAL(rtype) ||
1859 (IS_BITVAR(ltype) && IN_BITSPACE(SPEC_OCLS(ltype))))
1865 /*-----------------------------------------------------------------*/
1866 /* packRegsForAccUse - pack registers for acc use */
1867 /*-----------------------------------------------------------------*/
1868 static void packRegsForAccUse (iCode *ic)
1872 /* if + or - then it has to be one byte result */
1873 if ((ic->op == '+' || ic->op == '-')
1874 && getSize(operandType(IC_RESULT(ic))) > 1)
1877 /* if shift operation make sure right side is not a literal */
1878 if (ic->op == RIGHT_OP &&
1879 ( isOperandLiteral(IC_RIGHT(ic)) ||
1880 getSize(operandType(IC_RESULT(ic))) > 1))
1883 if (ic->op == LEFT_OP &&
1884 ( isOperandLiteral(IC_RIGHT(ic)) ||
1885 getSize(operandType(IC_RESULT(ic))) > 1))
1888 if (IS_BITWISE_OP(ic) &&
1889 getSize(operandType(IC_RESULT(ic))) > 1)
1893 /* has only one definition */
1894 if (bitVectnBitsOn(OP_DEFS(IC_RESULT(ic))) > 1)
1897 /* has only one use */
1898 if (bitVectnBitsOn(OP_USES(IC_RESULT(ic))) > 1)
1901 /* and the usage immediately follows this iCode */
1902 if (!(uic = hTabItemWithKey(iCodehTab,
1903 bitVectFirstBit(OP_USES(IC_RESULT(ic))))))
1906 if (ic->next != uic)
1909 /* if it is a conditional branch then we definitely can */
1910 if (uic->op == IFX )
1913 if ( uic->op == JUMPTABLE )
1916 /* if the usage is not is an assignment
1917 or an arithmetic / bitwise / shift operation then not */
1918 if (POINTER_SET(uic) &&
1919 getSize(aggrToPtr(operandType(IC_RESULT(uic)),FALSE)) > 1)
1922 if (uic->op != '=' &&
1923 !IS_ARITHMETIC_OP(uic) &&
1924 !IS_BITWISE_OP(uic) &&
1925 uic->op != LEFT_OP &&
1926 uic->op != RIGHT_OP )
1929 /* if used in ^ operation then make sure right is not a
1931 if (uic->op == '^' && isOperandLiteral(IC_RIGHT(uic)))
1934 /* if shift operation make sure right side is not a literal */
1935 if (uic->op == RIGHT_OP &&
1936 ( isOperandLiteral(IC_RIGHT(uic)) ||
1937 getSize(operandType(IC_RESULT(uic))) > 1))
1940 if (uic->op == LEFT_OP &&
1941 ( isOperandLiteral(IC_RIGHT(uic)) ||
1942 getSize(operandType(IC_RESULT(uic))) > 1))
1945 /* make sure that the result of this icode is not on the
1946 stack, since acc is used to compute stack offset */
1947 if (IS_TRUE_SYMOP(IC_RESULT(uic)) &&
1948 OP_SYMBOL(IC_RESULT(uic))->onStack)
1951 /* if either one of them in far space then we cannot */
1952 if ((IS_TRUE_SYMOP(IC_LEFT(uic)) &&
1953 isOperandInFarSpace(IC_LEFT(uic))) ||
1954 (IS_TRUE_SYMOP(IC_RIGHT(uic)) &&
1955 isOperandInFarSpace(IC_RIGHT(uic))))
1958 /* if the usage has only one operand then we can */
1959 if (IC_LEFT(uic) == NULL ||
1960 IC_RIGHT(uic) == NULL)
1963 /* make sure this is on the left side if not
1964 a '+' since '+' is commutative */
1965 if (ic->op != '+' &&
1966 IC_LEFT(uic)->key != IC_RESULT(ic)->key)
1969 /* if one of them is a literal then we can */
1970 if ((IC_LEFT(uic) && IS_OP_LITERAL(IC_LEFT(uic))) ||
1971 (IC_RIGHT(uic) && IS_OP_LITERAL(IC_RIGHT(uic)))) {
1972 OP_SYMBOL(IC_RESULT(ic))->accuse = 1;
1976 /* if the other one is not on stack then we can */
1977 if (IC_LEFT(uic)->key == IC_RESULT(ic)->key &&
1978 (IS_ITEMP(IC_RIGHT(uic)) ||
1979 (IS_TRUE_SYMOP(IC_RIGHT(uic)) &&
1980 !OP_SYMBOL(IC_RIGHT(uic))->onStack)))
1983 if (IC_RIGHT(uic)->key == IC_RESULT(ic)->key &&
1984 (IS_ITEMP(IC_LEFT(uic)) ||
1985 (IS_TRUE_SYMOP(IC_LEFT(uic)) &&
1986 !OP_SYMBOL(IC_LEFT(uic))->onStack)))
1992 OP_SYMBOL(IC_RESULT(ic))->accuse = 1;
1997 /*-----------------------------------------------------------------*/
1998 /* packForPush - hueristics to reduce iCode for pushing */
1999 /*-----------------------------------------------------------------*/
2000 static void packForPush(iCode *ic, eBBlock *ebp)
2004 if (ic->op != IPUSH || !IS_ITEMP(IC_LEFT(ic)))
2007 /* must have only definition & one usage */
2008 if (bitVectnBitsOn(OP_DEFS(IC_LEFT(ic))) != 1 ||
2009 bitVectnBitsOn(OP_USES(IC_LEFT(ic))) != 1 )
2012 /* find the definition */
2013 if (!(dic = hTabItemWithKey(iCodehTab,
2014 bitVectFirstBit(OP_DEFS(IC_LEFT(ic))))))
2017 if (dic->op != '=' || POINTER_SET(dic))
2020 /* we now we know that it has one & only one def & use
2021 and the that the definition is an assignment */
2022 IC_LEFT(ic) = IC_RIGHT(dic);
2024 remiCodeFromeBBlock(ebp,dic);
2025 hTabDeleteItem (&iCodehTab,dic->key,dic,DELETE_ITEM,NULL);
2028 /*-----------------------------------------------------------------*/
2029 /* packRegisters - does some transformations to reduce register */
2031 /*-----------------------------------------------------------------*/
2032 static void packRegisters (eBBlock *ebp)
2041 /* look for assignments of the form */
2042 /* iTempNN = TRueSym (someoperation) SomeOperand */
2044 /* TrueSym := iTempNN:1 */
2045 for ( ic = ebp->sch ; ic ; ic = ic->next ) {
2048 /* find assignment of the form TrueSym := iTempNN:1 */
2049 if (ic->op == '=' && !POINTER_SET(ic))
2050 change += packRegsForAssign(ic,ebp);
2057 for ( ic = ebp->sch ; ic ; ic = ic->next ) {
2059 /* if this is an itemp & result of a address of a true sym
2060 then mark this as rematerialisable */
2061 if (ic->op == ADDRESS_OF &&
2062 IS_ITEMP(IC_RESULT(ic)) &&
2063 IS_TRUE_SYMOP(IC_LEFT(ic)) &&
2064 bitVectnBitsOn(OP_DEFS(IC_RESULT(ic))) == 1 &&
2065 !OP_SYMBOL(IC_LEFT(ic))->onStack ) {
2067 OP_SYMBOL(IC_RESULT(ic))->remat = 1;
2068 OP_SYMBOL(IC_RESULT(ic))->rematiCode = ic;
2069 OP_SYMBOL(IC_RESULT(ic))->usl.spillLoc = NULL;
2073 /* if straight assignment then carry remat flag if
2074 this is the only definition */
2075 if (ic->op == '=' &&
2077 IS_SYMOP(IC_RIGHT(ic)) &&
2078 OP_SYMBOL(IC_RIGHT(ic))->remat &&
2079 bitVectnBitsOn(OP_SYMBOL(IC_RESULT(ic))->defs) <= 1) {
2081 OP_SYMBOL(IC_RESULT(ic))->remat =
2082 OP_SYMBOL(IC_RIGHT(ic))->remat;
2083 OP_SYMBOL(IC_RESULT(ic))->rematiCode =
2084 OP_SYMBOL(IC_RIGHT(ic))->rematiCode ;
2087 /* if this is a +/- operation with a rematerizable
2088 then mark this as rematerializable as well only
2089 if the literal value is within the range -255 and + 255
2090 the assembler cannot handle it other wise */
2091 if ((ic->op == '+' || ic->op == '-') &&
2093 (IS_SYMOP(IC_LEFT(ic)) &&
2094 IS_ITEMP(IC_RESULT(ic)) &&
2095 OP_SYMBOL(IC_LEFT(ic))->remat &&
2096 bitVectnBitsOn(OP_DEFS(IC_RESULT(ic))) == 1 &&
2097 IS_OP_LITERAL(IC_RIGHT(ic))) ) {
2099 int i = operandLitValue(IC_RIGHT(ic));
2100 if ( i < 255 && i > -255) {
2101 OP_SYMBOL(IC_RESULT(ic))->remat = 1;
2102 OP_SYMBOL(IC_RESULT(ic))->rematiCode = ic;
2103 OP_SYMBOL(IC_RESULT(ic))->usl.spillLoc = NULL;
2107 /* mark the pointer usages */
2108 if (POINTER_SET(ic))
2109 OP_SYMBOL(IC_RESULT(ic))->uptr = 1;
2111 if (POINTER_GET(ic))
2112 OP_SYMBOL(IC_LEFT(ic))->uptr = 1;
2114 if (!SKIP_IC2(ic)) {
2115 /* if we are using a symbol on the stack
2116 then we should say mcs51_ptrRegReq */
2117 if (ic->op == IFX && IS_SYMOP(IC_COND(ic)))
2118 mcs51_ptrRegReq += ((OP_SYMBOL(IC_COND(ic))->onStack ||
2119 OP_SYMBOL(IC_COND(ic))->iaccess) ? 1 : 0);
2121 if (ic->op == JUMPTABLE && IS_SYMOP(IC_JTCOND(ic)))
2122 mcs51_ptrRegReq += ((OP_SYMBOL(IC_JTCOND(ic))->onStack ||
2123 OP_SYMBOL(IC_JTCOND(ic))->iaccess) ? 1 : 0);
2125 if (IS_SYMOP(IC_LEFT(ic)))
2126 mcs51_ptrRegReq += ((OP_SYMBOL(IC_LEFT(ic))->onStack ||
2127 OP_SYMBOL(IC_LEFT(ic))->iaccess) ? 1 : 0);
2128 if (IS_SYMOP(IC_RIGHT(ic)))
2129 mcs51_ptrRegReq += ((OP_SYMBOL(IC_RIGHT(ic))->onStack ||
2130 OP_SYMBOL(IC_RIGHT(ic))->iaccess) ? 1 : 0);
2131 if (IS_SYMOP(IC_RESULT(ic)))
2132 mcs51_ptrRegReq += ((OP_SYMBOL(IC_RESULT(ic))->onStack ||
2133 OP_SYMBOL(IC_RESULT(ic))->iaccess) ? 1 : 0);
2137 /* if the condition of an if instruction
2138 is defined in the previous instruction then
2139 mark the itemp as a conditional */
2140 if ((IS_CONDITIONAL(ic) ||
2141 ( ( ic->op == BITWISEAND ||
2144 isBitwiseOptimizable(ic))) &&
2145 ic->next && ic->next->op == IFX &&
2146 isOperandEqual(IC_RESULT(ic),IC_COND(ic->next)) &&
2147 OP_SYMBOL(IC_RESULT(ic))->liveTo <= ic->next->seq) {
2149 OP_SYMBOL(IC_RESULT(ic))->regType = REG_CND;
2153 /* reduce for support function calls */
2154 if (ic->supportRtn || ic->op == '+' || ic->op == '-' )
2155 packRegsForSupport (ic,ebp);
2157 /* some cases the redundant moves can
2158 can be eliminated for return statements */
2159 if ((ic->op == RETURN || ic->op == SEND) &&
2160 !isOperandInFarSpace(IC_LEFT(ic)) &&
2162 packRegsForOneuse (ic,IC_LEFT(ic),ebp);
2164 /* if pointer set & left has a size more than
2165 one and right is not in far space */
2166 if (POINTER_SET(ic) &&
2167 !isOperandInFarSpace(IC_RIGHT(ic)) &&
2168 !OP_SYMBOL(IC_RESULT(ic))->remat &&
2169 !IS_OP_RUONLY(IC_RIGHT(ic)) &&
2170 getSize(aggrToPtr(operandType(IC_RESULT(ic)),FALSE)) > 1 )
2172 packRegsForOneuse (ic,IC_RESULT(ic),ebp);
2174 /* if pointer get */
2175 if (POINTER_GET(ic) &&
2176 !isOperandInFarSpace(IC_RESULT(ic))&&
2177 !OP_SYMBOL(IC_LEFT(ic))->remat &&
2178 !IS_OP_RUONLY(IC_RESULT(ic)) &&
2179 getSize(aggrToPtr(operandType(IC_LEFT(ic)),FALSE)) > 1 )
2181 packRegsForOneuse (ic,IC_LEFT(ic),ebp);
2184 /* if this is cast for intergral promotion then
2185 check if only use of the definition of the
2186 operand being casted/ if yes then replace
2187 the result of that arithmetic operation with
2188 this result and get rid of the cast */
2189 if (ic->op == CAST) {
2190 link *fromType = operandType(IC_RIGHT(ic));
2191 link *toType = operandType(IC_LEFT(ic));
2193 if (IS_INTEGRAL(fromType) && IS_INTEGRAL(toType) &&
2194 getSize(fromType) != getSize(toType) ) {
2196 iCode *dic = packRegsForOneuse(ic,IC_RIGHT(ic),ebp);
2198 if (IS_ARITHMETIC_OP(dic)) {
2199 IC_RESULT(dic) = IC_RESULT(ic);
2200 remiCodeFromeBBlock(ebp,ic);
2201 hTabDeleteItem (&iCodehTab,ic->key,ic,DELETE_ITEM,NULL);
2204 OP_SYMBOL(IC_RIGHT(ic))->ruonly = 0;
2208 /* if the type from and type to are the same
2209 then if this is the only use then packit */
2210 if (checkType(operandType(IC_RIGHT(ic)),
2211 operandType(IC_LEFT(ic))) == 1) {
2212 iCode *dic = packRegsForOneuse (ic,IC_RIGHT(ic),ebp);
2214 IC_RESULT(dic) = IC_RESULT(ic);
2215 remiCodeFromeBBlock(ebp,ic);
2216 hTabDeleteItem (&iCodehTab,ic->key,ic,DELETE_ITEM,NULL);
2224 iTempNN := (some variable in farspace) V1
2229 if (ic->op == IPUSH ) {
2230 packForPush(ic,ebp);
2234 /* pack registers for accumulator use, when the
2235 result of an arithmetic or bit wise operation
2236 has only one use, that use is immediately following
2237 the defintion and the using iCode has only one
2238 operand or has two operands but one is literal &
2239 the result of that operation is not on stack then
2240 we can leave the result of this operation in acc:b
2242 if ((IS_ARITHMETIC_OP(ic)
2244 || IS_BITWISE_OP(ic)
2246 || ic->op == LEFT_OP || ic->op == RIGHT_OP
2249 IS_ITEMP(IC_RESULT(ic)) &&
2250 getSize(operandType(IC_RESULT(ic))) <= 2)
2252 packRegsForAccUse (ic);
2257 /*-----------------------------------------------------------------*/
2258 /* assignRegisters - assigns registers to each live range as need */
2259 /*-----------------------------------------------------------------*/
2260 void mcs51_assignRegisters (eBBlock **ebbs, int count)
2265 setToNull((void *)&_G.funcrUsed);
2266 mcs51_ptrRegReq = _G.stackExtend = _G.dataExtend = 0;
2267 /* if not register extentions then reduce number
2269 if (options.regExtend)
2274 /* change assignments this will remove some
2275 live ranges reducing some register pressure */
2276 for (i = 0 ; i < count ;i++ )
2277 packRegisters (ebbs[i]);
2279 if (options.dump_pack)
2280 dumpEbbsToFileExt(".dumppack",ebbs,count);
2282 /* first determine for each live range the number of
2283 registers & the type of registers required for each */
2286 /* and serially allocate registers */
2287 serialRegAssign(ebbs,count);
2289 /* if stack was extended then tell the user */
2290 if (_G.stackExtend) {
2291 /* werror(W_TOOMANY_SPILS,"stack", */
2292 /* _G.stackExtend,currFunc->name,""); */
2293 _G.stackExtend = 0 ;
2296 if (_G.dataExtend) {
2297 /* werror(W_TOOMANY_SPILS,"data space", */
2298 /* _G.dataExtend,currFunc->name,""); */
2302 /* after that create the register mask
2303 for each of the instruction */
2304 createRegMask (ebbs,count);
2306 /* redo that offsets for stacked automatic variables */
2307 redoStackOffsets ();
2309 if (options.dump_rassgn)
2310 dumpEbbsToFileExt(".dumprassgn",ebbs,count);
2312 /* now get back the chain */
2313 ic = iCodeLabelOptimize(iCodeFromeBBlock (ebbs,count));
2318 /* free up any _G.stackSpil locations allocated */
2319 applyToSet(_G.stackSpil,deallocStackSpil);
2321 setToNull((void **)&_G.stackSpil);
2322 setToNull((void **)&_G.spiltSet);
2323 /* mark all registers as free */