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,ebp->fSeq,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
484 useXstack = options.useXstack;
485 model = options.model;
486 /* noOverlay = options.noOverlay; */
487 /* options.noOverlay = 1; */
488 options.model = options.useXstack = 0;
492 options.useXstack = useXstack;
493 options.model = model;
494 /* options.noOverlay = noOverlay; */
495 sloc->isref = 1; /* to prevent compiler warning */
497 /* if it is on the stack then update the stack */
498 if (IN_STACK(sloc->etype)) {
499 currFunc->stack += getSize(sloc->type);
500 _G.stackExtend += getSize(sloc->type);
502 _G.dataExtend += getSize(sloc->type);
504 /* add it to the _G.stackSpil set */
505 addSetHead(&_G.stackSpil,sloc);
506 sym->usl.spillLoc = sloc;
509 /* add it to the set of itempStack set
510 of the spill location */
511 addSetHead(&sloc->usl.itmpStack,sym);
515 /*-----------------------------------------------------------------*/
516 /* isSpiltOnStack - returns true if the spil location is on stack */
517 /*-----------------------------------------------------------------*/
518 static bool isSpiltOnStack (symbol *sym)
528 /* if (sym->_G.stackSpil) */
531 if (!sym->usl.spillLoc)
534 etype = getSpec(sym->usl.spillLoc->type);
541 /*-----------------------------------------------------------------*/
542 /* spillThis - spils a specific operand */
543 /*-----------------------------------------------------------------*/
544 static void spillThis (symbol *sym)
547 /* if this is rematerializable or has a spillLocation
548 we are okay, else we need to create a spillLocation
550 if (!(sym->remat || sym->usl.spillLoc))
551 createStackSpil (sym);
554 /* mark it has spilt & put it in the spilt set */
556 _G.spiltSet = bitVectSetBit(_G.spiltSet,sym->key);
558 bitVectUnSetBit(_G.regAssigned,sym->key);
560 for (i = 0 ; i < sym->nRegs ; i++)
563 freeReg(sym->regs[i]);
567 /* if spilt on stack then free up r0 & r1
568 if they could have been assigned to some
570 if (!mcs51_ptrRegReq && isSpiltOnStack(sym)) {
572 spillLRWithPtrReg(sym);
575 if (sym->usl.spillLoc && !sym->remat)
576 sym->usl.spillLoc->allocreq = 1;
580 /*-----------------------------------------------------------------*/
581 /* selectSpil - select a iTemp to spil : rather a simple procedure */
582 /*-----------------------------------------------------------------*/
583 static symbol *selectSpil (iCode *ic, eBBlock *ebp, symbol *forSym)
585 bitVect *lrcs= NULL ;
589 /* get the spillable live ranges */
590 lrcs = computeSpillable (ic);
592 /* get all live ranges that are rematerizable */
593 if ((selectS = liveRangesWith(lrcs,rematable,ebp,ic))) {
595 /* return the least used of these */
596 return leastUsedLR(selectS);
599 /* get live ranges with spillLocations in direct space */
600 if ((selectS = liveRangesWith(lrcs,directSpilLoc,ebp,ic))) {
601 sym = leastUsedLR(selectS);
602 strcpy(sym->rname,(sym->usl.spillLoc->rname[0] ?
603 sym->usl.spillLoc->rname :
604 sym->usl.spillLoc->name));
606 /* mark it as allocation required */
607 sym->usl.spillLoc->allocreq = 1;
611 /* if the symbol is local to the block then */
612 if (forSym->liveTo < ebp->lSeq) {
614 /* check if there are any live ranges allocated
615 to registers that are not used in this block */
616 if (!_G.blockSpil && (selectS = liveRangesWith(lrcs,notUsedInBlock,ebp,ic))) {
617 sym = leastUsedLR(selectS);
618 /* if this is not rematerializable */
626 /* check if there are any live ranges that not
627 used in the remainder of the block */
628 if (!_G.blockSpil && (selectS = liveRangesWith(lrcs,notUsedInRemaining,ebp,ic))) {
629 sym = leastUsedLR (selectS);
640 /* find live ranges with spillocation && not used as pointers */
641 if ((selectS = liveRangesWith(lrcs,hasSpilLocnoUptr,ebp,ic))) {
643 sym = leastUsedLR(selectS);
644 /* mark this as allocation required */
645 sym->usl.spillLoc->allocreq = 1;
649 /* find live ranges with spillocation */
650 if ((selectS = liveRangesWith(lrcs,hasSpilLoc,ebp,ic))) {
652 sym = leastUsedLR(selectS);
653 sym->usl.spillLoc->allocreq = 1;
657 /* couldn't find then we need to create a spil
658 location on the stack , for which one? the least
660 if ((selectS = liveRangesWith(lrcs,noSpilLoc,ebp,ic))) {
662 /* return a created spil location */
663 sym = createStackSpil(leastUsedLR(selectS));
664 sym->usl.spillLoc->allocreq = 1;
668 /* this is an extreme situation we will spill
669 this one : happens very rarely but it does happen */
670 spillThis ( forSym );
675 /*-----------------------------------------------------------------*/
676 /* spilSomething - spil some variable & mark registers as free */
677 /*-----------------------------------------------------------------*/
678 static bool spilSomething (iCode *ic, eBBlock *ebp, symbol *forSym)
683 /* get something we can spil */
684 ssym = selectSpil(ic,ebp,forSym);
686 /* mark it as spilt */
688 _G.spiltSet = bitVectSetBit(_G.spiltSet,ssym->key);
690 /* mark it as not register assigned &
691 take it away from the set */
692 bitVectUnSetBit(_G.regAssigned,ssym->key);
694 /* mark the registers as free */
695 for (i = 0 ; i < ssym->nRegs ;i++ )
697 freeReg(ssym->regs[i]);
699 /* if spilt on stack then free up r0 & r1
700 if they could have been assigned to as gprs */
701 if (!mcs51_ptrRegReq && isSpiltOnStack(ssym) ) {
703 spillLRWithPtrReg(ssym);
706 /* if this was a block level spil then insert push & pop
707 at the start & end of block respectively */
708 if (ssym->blockSpil) {
709 iCode *nic = newiCode(IPUSH,operandFromSymbol(ssym),NULL);
710 /* add push to the start of the block */
711 addiCodeToeBBlock(ebp,nic,( ebp->sch->op == LABEL ?
712 ebp->sch->next : ebp->sch));
713 nic = newiCode(IPOP,operandFromSymbol(ssym),NULL);
714 /* add pop to the end of the block */
715 addiCodeToeBBlock(ebp,nic,NULL);
718 /* if spilt because not used in the remainder of the
719 block then add a push before this instruction and
720 a pop at the end of the block */
721 if (ssym->remainSpil) {
723 iCode *nic = newiCode(IPUSH,operandFromSymbol(ssym),NULL);
724 /* add push just before this instruction */
725 addiCodeToeBBlock(ebp,nic,ic);
727 nic = newiCode(IPOP,operandFromSymbol(ssym),NULL);
728 /* add pop to the end of the block */
729 addiCodeToeBBlock(ebp,nic,NULL);
738 /*-----------------------------------------------------------------*/
739 /* getRegPtr - will try for PTR if not a GPR type if not spil */
740 /*-----------------------------------------------------------------*/
741 static regs *getRegPtr (iCode *ic, eBBlock *ebp, symbol *sym)
746 /* try for a ptr type */
747 if ((reg = allocReg(REG_PTR)))
750 /* try for gpr type */
751 if ((reg = allocReg(REG_GPR)))
754 /* we have to spil */
755 if (!spilSomething (ic,ebp,sym))
758 /* this looks like an infinite loop but
759 in really selectSpil will abort */
763 /*-----------------------------------------------------------------*/
764 /* getRegGpr - will try for GPR if not spil */
765 /*-----------------------------------------------------------------*/
766 static regs *getRegGpr (iCode *ic, eBBlock *ebp,symbol *sym)
771 /* try for gpr type */
772 if ((reg = allocReg(REG_GPR)))
775 if (!mcs51_ptrRegReq)
776 if ((reg = allocReg(REG_PTR)))
779 /* we have to spil */
780 if (!spilSomething (ic,ebp,sym))
783 /* this looks like an infinite loop but
784 in really selectSpil will abort */
788 /*-----------------------------------------------------------------*/
789 /* symHasReg - symbol has a given register */
790 /*-----------------------------------------------------------------*/
791 static bool symHasReg(symbol *sym,regs *reg)
795 for ( i = 0 ; i < sym->nRegs ; i++)
796 if (sym->regs[i] == reg)
802 /*-----------------------------------------------------------------*/
803 /* deassignLRs - check the live to and if they have registers & are*/
804 /* not spilt then free up the registers */
805 /*-----------------------------------------------------------------*/
806 static void deassignLRs (iCode *ic, eBBlock *ebp)
812 for (sym = hTabFirstItem(liveRanges,&k); sym;
813 sym = hTabNextItem(liveRanges,&k)) {
816 /* if it does not end here */
817 if (sym->liveTo > ic->seq )
820 /* if it was spilt on stack then we can
821 mark the stack spil location as free */
823 if (sym->stackSpil) {
824 sym->usl.spillLoc->isFree = 1;
830 if (!bitVectBitValue(_G.regAssigned,sym->key))
833 /* special case check if this is an IFX &
834 the privious one was a pop and the
835 previous one was not spilt then keep track
837 if (ic->op == IFX && ic->prev &&
838 ic->prev->op == IPOP &&
839 !ic->prev->parmPush &&
840 !OP_SYMBOL(IC_LEFT(ic->prev))->isspilt)
841 psym = OP_SYMBOL(IC_LEFT(ic->prev));
846 bitVectUnSetBit(_G.regAssigned,sym->key);
848 /* if the result of this one needs registers
849 and does not have it then assign it right
852 ! (SKIP_IC2(ic) || /* not a special icode */
853 ic->op == JUMPTABLE ||
859 (result = OP_SYMBOL(IC_RESULT(ic))) && /* has a result */
860 result->liveTo > ic->seq && /* and will live beyond this */
861 result->liveTo <= ebp->lSeq && /* does not go beyond this block */
862 result->regType == sym->regType && /* same register types */
863 result->nRegs && /* which needs registers */
864 ! result->isspilt && /* and does not already have them */
866 ! bitVectBitValue(_G.regAssigned,result->key) &&
867 /* the number of free regs + number of regs in this LR
868 can accomodate the what result Needs */
869 ((nfreeRegsType(result->regType) +
870 sym->nRegs) >= result->nRegs)
873 for (i = 0 ; i < result->nRegs ; i++)
875 result->regs[i] = sym->regs[i] ;
877 result->regs[i] = getRegGpr (ic,ebp,result);
879 _G.regAssigned = bitVectSetBit(_G.regAssigned,result->key);
883 /* free the remaining */
884 for (; i < sym->nRegs ; i++) {
886 if (!symHasReg(psym,sym->regs[i]))
887 freeReg(sym->regs[i]);
889 freeReg(sym->regs[i]);
896 /*-----------------------------------------------------------------*/
897 /* reassignLR - reassign this to registers */
898 /*-----------------------------------------------------------------*/
899 static void reassignLR (operand *op)
901 symbol *sym = OP_SYMBOL(op);
904 /* not spilt any more */
905 sym->isspilt = sym->blockSpil = sym->remainSpil = 0;
906 bitVectUnSetBit(_G.spiltSet,sym->key);
908 _G.regAssigned = bitVectSetBit(_G.regAssigned,sym->key);
912 for (i=0;i<sym->nRegs;i++)
913 sym->regs[i]->isFree = 0;
916 /*-----------------------------------------------------------------*/
917 /* willCauseSpill - determines if allocating will cause a spill */
918 /*-----------------------------------------------------------------*/
919 static int willCauseSpill ( int nr, int rt)
921 /* first check if there are any avlb registers
922 of te type required */
924 /* special case for pointer type
925 if pointer type not avlb then
926 check for type gpr */
927 if (nFreeRegs(rt) >= nr)
929 if (nFreeRegs(REG_GPR) >= nr)
932 if (mcs51_ptrRegReq) {
933 if (nFreeRegs(rt) >= nr)
936 if (nFreeRegs(REG_PTR) +
937 nFreeRegs(REG_GPR) >= nr)
942 /* it will cause a spil */
946 /*-----------------------------------------------------------------*/
947 /* positionRegs - the allocator can allocate same registers to res-*/
948 /* ult and operand, if this happens make sure they are in the same */
949 /* position as the operand otherwise chaos results */
950 /*-----------------------------------------------------------------*/
951 static void positionRegs (symbol *result, symbol *opsym, int lineno)
953 int count = min(result->nRegs,opsym->nRegs);
954 int i , j = 0, shared = 0;
956 /* if the result has been spilt then cannot share */
961 /* first make sure that they actually share */
962 for ( i = 0 ; i < count; i++ ) {
963 for (j = 0 ; j < count ; j++ ) {
964 if (result->regs[i] == opsym->regs[j] && i !=j) {
972 regs *tmp = result->regs[i];
973 result->regs[i] = result->regs[j];
974 result->regs[j] = tmp;
979 /*-----------------------------------------------------------------*/
980 /* serialRegAssign - serially allocate registers to the variables */
981 /*-----------------------------------------------------------------*/
982 static void serialRegAssign (eBBlock **ebbs, int count)
987 for (i = 0; i < count ; i++ ) {
991 if (ebbs[i]->noPath &&
992 (ebbs[i]->entryLabel != entryLabel &&
993 ebbs[i]->entryLabel != returnLabel ))
996 /* of all instructions do */
997 for (ic = ebbs[i]->sch ; ic ; ic = ic->next) {
999 /* if this is an ipop that means some live
1000 range will have to be assigned again */
1002 reassignLR (IC_LEFT(ic));
1004 /* if result is present && is a true symbol */
1005 if (IC_RESULT(ic) && ic->op != IFX &&
1006 IS_TRUE_SYMOP(IC_RESULT(ic)))
1007 OP_SYMBOL(IC_RESULT(ic))->allocreq = 1;
1009 /* take away registers from live
1010 ranges that end at this instruction */
1011 deassignLRs (ic, ebbs[i]) ;
1013 /* some don't need registers */
1015 ic->op == JUMPTABLE ||
1019 (IC_RESULT(ic) &&POINTER_SET(ic)) )
1022 /* now we need to allocate registers
1023 only for the result */
1024 if (IC_RESULT(ic)) {
1025 symbol *sym = OP_SYMBOL(IC_RESULT(ic));
1031 /* if it does not need or is spilt
1032 or is already assigned to registers
1033 or will not live beyond this instructions */
1036 bitVectBitValue(_G.regAssigned,sym->key) ||
1037 sym->liveTo <= ic->seq)
1040 /* if some liverange has been spilt at the block level
1041 and this one live beyond this block then spil this
1043 if (_G.blockSpil && sym->liveTo > ebbs[i]->lSeq) {
1047 /* if trying to allocate this will cause
1048 a spill and there is nothing to spill
1049 or this one is rematerializable then
1051 willCS = willCauseSpill(sym->nRegs,sym->regType);
1052 spillable = computeSpillable(ic);
1054 (willCS && bitVectIsZero(spillable) ) ) {
1061 /* if it has a spillocation & is used less than
1062 all other live ranges then spill this */
1063 if ( willCS && sym->usl.spillLoc ) {
1066 leastUsedLR(liveRangesWith (spillable ,
1071 leastUsed->used > sym->used) {
1077 /* if we need ptr regs for the right side
1079 if (POINTER_GET(ic) && getSize(OP_SYMBOL(IC_LEFT(ic))->type)
1085 /* else we assign registers to it */
1086 _G.regAssigned = bitVectSetBit(_G.regAssigned,sym->key);
1088 for (j = 0 ; j < sym->nRegs ;j++ ) {
1089 if (sym->regType == REG_PTR)
1090 sym->regs[j] = getRegPtr(ic,ebbs[i],sym);
1092 sym->regs[j] = getRegGpr(ic,ebbs[i],sym);
1094 /* if the allocation falied which means
1095 this was spilt then break */
1099 /* if it shares registers with operands make sure
1100 that they are in the same position */
1101 if (IC_LEFT(ic) && IS_SYMOP(IC_LEFT(ic)) &&
1102 OP_SYMBOL(IC_LEFT(ic))->nRegs && ic->op != '=')
1103 positionRegs(OP_SYMBOL(IC_RESULT(ic)),
1104 OP_SYMBOL(IC_LEFT(ic)),ic->lineno);
1105 /* do the same for the right operand */
1106 if (IC_RIGHT(ic) && IS_SYMOP(IC_RIGHT(ic)) &&
1107 OP_SYMBOL(IC_RIGHT(ic))->nRegs)
1108 positionRegs(OP_SYMBOL(IC_RESULT(ic)),
1109 OP_SYMBOL(IC_RIGHT(ic)),ic->lineno);
1121 /*-----------------------------------------------------------------*/
1122 /* rUmaskForOp :- returns register mask for an operand */
1123 /*-----------------------------------------------------------------*/
1124 static bitVect *rUmaskForOp (operand *op)
1130 /* only temporaries are assigned registers */
1134 sym = OP_SYMBOL(op);
1136 /* if spilt or no registers assigned to it
1138 if (sym->isspilt || !sym->nRegs)
1141 rumask = newBitVect(mcs51_nRegs);
1143 for (j = 0; j < sym->nRegs; j++) {
1144 rumask = bitVectSetBit(rumask,
1145 sym->regs[j]->rIdx);
1151 /*-----------------------------------------------------------------*/
1152 /* regsUsedIniCode :- returns bit vector of registers used in iCode*/
1153 /*-----------------------------------------------------------------*/
1154 static bitVect *regsUsedIniCode (iCode *ic)
1156 bitVect *rmask = newBitVect(mcs51_nRegs);
1158 /* do the special cases first */
1159 if (ic->op == IFX ) {
1160 rmask = bitVectUnion(rmask,
1161 rUmaskForOp(IC_COND(ic)));
1165 /* for the jumptable */
1166 if (ic->op == JUMPTABLE) {
1167 rmask = bitVectUnion(rmask,
1168 rUmaskForOp(IC_JTCOND(ic)));
1173 /* of all other cases */
1175 rmask = bitVectUnion(rmask,
1176 rUmaskForOp(IC_LEFT(ic)));
1180 rmask = bitVectUnion(rmask,
1181 rUmaskForOp(IC_RIGHT(ic)));
1184 rmask = bitVectUnion(rmask,
1185 rUmaskForOp(IC_RESULT(ic)));
1191 /*-----------------------------------------------------------------*/
1192 /* createRegMask - for each instruction will determine the regsUsed*/
1193 /*-----------------------------------------------------------------*/
1194 static void createRegMask (eBBlock **ebbs, int count)
1198 /* for all blocks */
1199 for (i = 0; i < count ; i++ ) {
1202 if ( ebbs[i]->noPath &&
1203 ( ebbs[i]->entryLabel != entryLabel &&
1204 ebbs[i]->entryLabel != returnLabel ))
1207 /* for all instructions */
1208 for ( ic = ebbs[i]->sch ; ic ; ic = ic->next ) {
1212 if (SKIP_IC2(ic) || !ic->rlive)
1215 /* first mark the registers used in this
1217 ic->rUsed = regsUsedIniCode(ic);
1218 _G.funcrUsed = bitVectUnion(_G.funcrUsed,ic->rUsed);
1220 /* now create the register mask for those
1221 registers that are in use : this is a
1222 super set of ic->rUsed */
1223 ic->rMask = newBitVect(mcs51_nRegs+1);
1225 /* for all live Ranges alive at this point */
1226 for (j = 1; j < ic->rlive->size; j++ ) {
1230 /* if not alive then continue */
1231 if (!bitVectBitValue(ic->rlive,j))
1234 /* find the live range we are interested in */
1235 if (!(sym = hTabItemWithKey(liveRanges,j))) {
1236 werror (E_INTERNAL_ERROR,__FILE__,__LINE__,
1237 "createRegMask cannot find live range");
1241 /* if no register assigned to it */
1242 if (!sym->nRegs || sym->isspilt)
1245 /* for all the registers allocated to it */
1246 for (k = 0 ; k < sym->nRegs ;k++)
1249 bitVectSetBit(ic->rMask,sym->regs[k]->rIdx);
1255 /*-----------------------------------------------------------------*/
1256 /* rematStr - returns the rematerialized string for a remat var */
1257 /*-----------------------------------------------------------------*/
1258 static char *rematStr (symbol *sym)
1261 iCode *ic = sym->rematiCode;
1265 /* if plus or minus print the right hand side */
1266 if (ic->op == '+' || ic->op == '-') {
1267 sprintf(s,"0x%04x %c ",(int) operandLitValue(IC_RIGHT(ic)),
1270 ic = OP_SYMBOL(IC_LEFT(ic))->rematiCode;
1274 /* we reached the end */
1275 sprintf(s,"%s",OP_SYMBOL(IC_LEFT(ic))->rname);
1282 /*-----------------------------------------------------------------*/
1283 /* regTypeNum - computes the type & number of registers required */
1284 /*-----------------------------------------------------------------*/
1285 static void regTypeNum ()
1291 /* for each live range do */
1292 for ( sym = hTabFirstItem(liveRanges,&k); sym ;
1293 sym = hTabNextItem(liveRanges,&k)) {
1295 /* if used zero times then no registers needed */
1296 if ((sym->liveTo - sym->liveFrom) == 0)
1300 /* if the live range is a temporary */
1303 /* if the type is marked as a conditional */
1304 if (sym->regType == REG_CND)
1307 /* if used in return only then we don't
1309 if (sym->ruonly || sym->accuse) {
1310 if (IS_AGGREGATE(sym->type) || sym->isptr)
1311 sym->type = aggrToPtr(sym->type,FALSE);
1315 /* if the symbol has only one definition &
1316 that definition is a get_pointer and the
1317 pointer we are getting is rematerializable and
1320 if (bitVectnBitsOn(sym->defs) == 1 &&
1321 (ic = hTabItemWithKey(iCodehTab,
1322 bitVectFirstBit(sym->defs))) &&
1324 !IS_BITVAR(sym->etype)) {
1327 /* if remat in data space */
1328 if (OP_SYMBOL(IC_LEFT(ic))->remat &&
1329 DCL_TYPE(aggrToPtr(sym->type,FALSE)) == POINTER) {
1331 /* create a psuedo symbol & force a spil */
1332 symbol *psym = newSymbol(rematStr(OP_SYMBOL(IC_LEFT(ic))),1);
1333 psym->type = sym->type;
1334 psym->etype = sym->etype;
1335 strcpy(psym->rname,psym->name);
1337 sym->usl.spillLoc = psym;
1341 /* if in data space or idata space then try to
1342 allocate pointer register */
1346 /* if not then we require registers */
1347 sym->nRegs = ((IS_AGGREGATE(sym->type) || sym->isptr ) ?
1348 getSize(sym->type = aggrToPtr(sym->type,FALSE)) :
1349 getSize(sym->type));
1351 if (sym->nRegs > 4) {
1352 fprintf(stderr,"allocated more than 4 or 0 registers for type ");
1353 printTypeChain(sym->type,stderr);fprintf(stderr,"\n");
1356 /* determine the type of register required */
1357 if (sym->nRegs == 1 &&
1358 IS_PTR(sym->type) &&
1360 sym->regType = REG_PTR ;
1362 sym->regType = REG_GPR ;
1365 /* for the first run we don't provide */
1366 /* registers for true symbols we will */
1367 /* see how things go */
1373 /*-----------------------------------------------------------------*/
1374 /* freeAllRegs - mark all registers as free */
1375 /*-----------------------------------------------------------------*/
1376 static void freeAllRegs()
1380 for (i=0;i< mcs51_nRegs;i++ )
1381 regs8051[i].isFree = 1;
1384 /*-----------------------------------------------------------------*/
1385 /* deallocStackSpil - this will set the stack pointer back */
1386 /*-----------------------------------------------------------------*/
1387 static DEFSETFUNC(deallocStackSpil)
1395 /*-----------------------------------------------------------------*/
1396 /* farSpacePackable - returns the packable icode for far variables */
1397 /*-----------------------------------------------------------------*/
1398 static iCode *farSpacePackable (iCode *ic)
1402 /* go thru till we find a definition for the
1403 symbol on the right */
1404 for ( dic = ic->prev ; dic ; dic = dic->prev) {
1406 /* if the definition is a call then no */
1407 if ((dic->op == CALL || dic->op == PCALL) &&
1408 IC_RESULT(dic)->key == IC_RIGHT(ic)->key) {
1412 /* if shift by unknown amount then not */
1413 if ((dic->op == LEFT_OP || dic->op == RIGHT_OP) &&
1414 IC_RESULT(dic)->key == IC_RIGHT(ic)->key)
1417 /* if pointer get and size > 1 */
1418 if (POINTER_GET(dic) &&
1419 getSize(aggrToPtr(operandType(IC_LEFT(dic)),FALSE)) > 1)
1422 if (POINTER_SET(dic) &&
1423 getSize(aggrToPtr(operandType(IC_RESULT(dic)),FALSE)) > 1)
1426 /* if any three is a true symbol in far space */
1427 if (IC_RESULT(dic) &&
1428 IS_TRUE_SYMOP(IC_RESULT(dic)) &&
1429 isOperandInFarSpace(IC_RESULT(dic)))
1432 if (IC_RIGHT(dic) &&
1433 IS_TRUE_SYMOP(IC_RIGHT(dic)) &&
1434 isOperandInFarSpace(IC_RIGHT(dic)) &&
1435 !isOperandEqual(IC_RIGHT(dic),IC_RESULT(ic)))
1439 IS_TRUE_SYMOP(IC_LEFT(dic)) &&
1440 isOperandInFarSpace(IC_LEFT(dic)) &&
1441 !isOperandEqual(IC_LEFT(dic),IC_RESULT(ic)))
1444 if (isOperandEqual(IC_RIGHT(ic),IC_RESULT(dic))) {
1445 if ( (dic->op == LEFT_OP ||
1446 dic->op == RIGHT_OP ||
1448 IS_OP_LITERAL(IC_RIGHT(dic)))
1458 /*-----------------------------------------------------------------*/
1459 /* packRegsForAssign - register reduction for assignment */
1460 /*-----------------------------------------------------------------*/
1461 static int packRegsForAssign (iCode *ic,eBBlock *ebp)
1465 if (!IS_ITEMP(IC_RIGHT(ic)) ||
1466 OP_SYMBOL(IC_RIGHT(ic))->isind ||
1467 OP_LIVETO(IC_RIGHT(ic)) > ic->seq) {
1471 /* if the true symbol is defined in far space or on stack
1472 then we should not since this will increase register pressure */
1473 if (isOperandInFarSpace(IC_RESULT(ic))) {
1474 if ((dic = farSpacePackable(ic)))
1480 /* find the definition of iTempNN scanning backwards if we find a
1481 a use of the true symbol in before we find the definition then
1483 for ( dic = ic->prev ; dic ; dic = dic->prev) {
1485 /* if there is a function call and this is
1486 a parameter & not my parameter then don't pack it */
1487 if ( (dic->op == CALL || dic->op == PCALL) &&
1488 (OP_SYMBOL(IC_RESULT(ic))->_isparm &&
1489 !OP_SYMBOL(IC_RESULT(ic))->ismyparm)) {
1497 if (IS_TRUE_SYMOP(IC_RESULT(dic)) &&
1498 IS_OP_VOLATILE(IC_RESULT(dic))) {
1503 if (IS_SYMOP(IC_RESULT(dic)) &&
1504 IC_RESULT(dic)->key == IC_RIGHT(ic)->key) {
1505 if (POINTER_SET(dic))
1511 if (IS_SYMOP(IC_RIGHT(dic)) &&
1512 (IC_RIGHT(dic)->key == IC_RESULT(ic)->key ||
1513 IC_RIGHT(dic)->key == IC_RIGHT(ic)->key)) {
1518 if (IS_SYMOP(IC_LEFT(dic)) &&
1519 (IC_LEFT(dic)->key == IC_RESULT(ic)->key ||
1520 IC_LEFT(dic)->key == IC_RIGHT(ic)->key)) {
1525 if (POINTER_SET(dic) &&
1526 IC_RESULT(dic)->key == IC_RESULT(ic)->key ) {
1533 return 0 ; /* did not find */
1535 /* if the result is on stack or iaccess then it must be
1536 the same atleast one of the operands */
1537 if (OP_SYMBOL(IC_RESULT(ic))->onStack ||
1538 OP_SYMBOL(IC_RESULT(ic))->iaccess ) {
1540 /* the operation has only one symbol
1541 operator then we can pack */
1542 if ((IC_LEFT(dic) && !IS_SYMOP(IC_LEFT(dic))) ||
1543 (IC_RIGHT(dic) && !IS_SYMOP(IC_RIGHT(dic))))
1546 if (!((IC_LEFT(dic) &&
1547 IC_RESULT(ic)->key == IC_LEFT(dic)->key) ||
1549 IC_RESULT(ic)->key == IC_RIGHT(dic)->key)))
1553 /* found the definition */
1554 /* replace the result with the result of */
1555 /* this assignment and remove this assignment */
1556 IC_RESULT(dic) = IC_RESULT(ic) ;
1558 if (IS_ITEMP(IC_RESULT(dic)) && OP_SYMBOL(IC_RESULT(dic))->liveFrom > dic->seq) {
1559 OP_SYMBOL(IC_RESULT(dic))->liveFrom = dic->seq;
1561 /* delete from liverange table also
1562 delete from all the points inbetween and the new
1564 for ( sic = dic; sic != ic ; sic = sic->next ) {
1565 bitVectUnSetBit(sic->rlive,IC_RESULT(ic)->key);
1566 if (IS_ITEMP(IC_RESULT(dic)))
1567 bitVectSetBit(sic->rlive,IC_RESULT(dic)->key);
1570 remiCodeFromeBBlock(ebp,ic);
1571 hTabDeleteItem (&iCodehTab,ic->key,ic,DELETE_ITEM,NULL);
1572 OP_DEFS(IC_RESULT(dic)) = bitVectSetBit(OP_DEFS(IC_RESULT(dic)),dic->key);
1577 /*-----------------------------------------------------------------*/
1578 /* findAssignToSym : scanning backwards looks for first assig found*/
1579 /*-----------------------------------------------------------------*/
1580 static iCode *findAssignToSym (operand *op,iCode *ic)
1584 for (dic = ic->prev ; dic ; dic = dic->prev) {
1586 /* if definition by assignment */
1587 if (dic->op == '=' &&
1588 !POINTER_SET(dic) &&
1589 IC_RESULT(dic)->key == op->key
1590 /* && IS_TRUE_SYMOP(IC_RIGHT(dic)) */
1593 /* we are interested only if defined in far space */
1594 /* or in stack space in case of + & - */
1596 /* if assigned to a non-symbol then return
1598 if (!IS_SYMOP(IC_RIGHT(dic)))
1601 /* if the symbol is in far space then
1603 if (isOperandInFarSpace(IC_RIGHT(dic)))
1606 /* for + & - operations make sure that
1607 if it is on the stack it is the same
1608 as one of the three operands */
1609 if ((ic->op == '+' || ic->op == '-') &&
1610 OP_SYMBOL(IC_RIGHT(dic))->onStack) {
1612 if ( IC_RESULT(ic)->key != IC_RIGHT(dic)->key &&
1613 IC_LEFT(ic)->key != IC_RIGHT(dic)->key &&
1614 IC_RIGHT(ic)->key != IC_RIGHT(dic)->key)
1622 /* if we find an usage then we cannot delete it */
1623 if (IC_LEFT(dic) && IC_LEFT(dic)->key == op->key)
1626 if (IC_RIGHT(dic) && IC_RIGHT(dic)->key == op->key)
1629 if (POINTER_SET(dic) && IC_RESULT(dic)->key == op->key)
1633 /* now make sure that the right side of dic
1634 is not defined between ic & dic */
1636 iCode *sic = dic->next ;
1638 for (; sic != ic ; sic = sic->next)
1639 if (IC_RESULT(sic) &&
1640 IC_RESULT(sic)->key == IC_RIGHT(dic)->key)
1649 /*-----------------------------------------------------------------*/
1650 /* packRegsForSupport :- reduce some registers for support calls */
1651 /*-----------------------------------------------------------------*/
1652 static int packRegsForSupport (iCode *ic, eBBlock *ebp)
1655 /* for the left & right operand :- look to see if the
1656 left was assigned a true symbol in far space in that
1657 case replace them */
1658 if (IS_ITEMP(IC_LEFT(ic)) &&
1659 OP_SYMBOL(IC_LEFT(ic))->liveTo <= ic->seq) {
1660 iCode *dic = findAssignToSym(IC_LEFT(ic),ic);
1666 /* found it we need to remove it from the
1668 for ( sic = dic; sic != ic ; sic = sic->next )
1669 bitVectUnSetBit(sic->rlive,IC_LEFT(ic)->key);
1671 IC_LEFT(ic)->operand.symOperand =
1672 IC_RIGHT(dic)->operand.symOperand;
1673 IC_LEFT(ic)->key = IC_RIGHT(dic)->operand.symOperand->key;
1674 remiCodeFromeBBlock(ebp,dic);
1675 hTabDeleteItem (&iCodehTab,dic->key,dic,DELETE_ITEM,NULL);
1679 /* do the same for the right operand */
1682 IS_ITEMP(IC_RIGHT(ic)) &&
1683 OP_SYMBOL(IC_RIGHT(ic))->liveTo <= ic->seq) {
1684 iCode *dic = findAssignToSym(IC_RIGHT(ic),ic);
1690 /* if this is a subtraction & the result
1691 is a true symbol in far space then don't pack */
1692 if (ic->op == '-' && IS_TRUE_SYMOP(IC_RESULT(dic))) {
1693 link *etype =getSpec(operandType(IC_RESULT(dic)));
1694 if (IN_FARSPACE(SPEC_OCLS(etype)))
1697 /* found it we need to remove it from the
1699 for ( sic = dic; sic != ic ; sic = sic->next )
1700 bitVectUnSetBit(sic->rlive,IC_RIGHT(ic)->key);
1702 IC_RIGHT(ic)->operand.symOperand =
1703 IC_RIGHT(dic)->operand.symOperand;
1704 IC_RIGHT(ic)->key = IC_RIGHT(dic)->operand.symOperand->key;
1706 remiCodeFromeBBlock(ebp,dic);
1707 hTabDeleteItem (&iCodehTab,dic->key,dic,DELETE_ITEM,NULL);
1714 #define IS_OP_RUONLY(x) (x && IS_SYMOP(x) && OP_SYMBOL(x)->ruonly)
1717 /*-----------------------------------------------------------------*/
1718 /* packRegsForOneuse : - will reduce some registers for single Use */
1719 /*-----------------------------------------------------------------*/
1720 static iCode *packRegsForOneuse (iCode *ic, operand *op , eBBlock *ebp)
1725 /* if returning a literal then do nothing */
1729 /* only upto 2 bytes since we cannot predict
1730 the usage of b, & acc */
1731 if (getSize(operandType(op)) > (fReturnSize - 2) &&
1738 /* this routine will mark the a symbol as used in one
1739 instruction use only && if the defintion is local
1740 (ie. within the basic block) && has only one definition &&
1741 that definiion is either a return value from a
1742 function or does not contain any variables in
1744 uses = bitVectCopy(OP_USES(op));
1745 bitVectUnSetBit(uses,ic->key); /* take away this iCode */
1746 if (!bitVectIsZero(uses)) /* has other uses */
1749 /* if it has only one defintion */
1750 if (bitVectnBitsOn(OP_DEFS(op)) > 1)
1751 return NULL ; /* has more than one definition */
1753 /* get the that definition */
1755 hTabItemWithKey(iCodehTab,
1756 bitVectFirstBit(OP_DEFS(op)))))
1759 /* found the definition now check if it is local */
1760 if (dic->seq < ebp->fSeq ||
1761 dic->seq > ebp->lSeq)
1762 return NULL ; /* non-local */
1764 /* now check if it is the return from
1766 if (dic->op == CALL || dic->op == PCALL ) {
1767 if (ic->op != SEND && ic->op != RETURN) {
1768 OP_SYMBOL(op)->ruonly = 1;
1775 /* otherwise check that the definition does
1776 not contain any symbols in far space */
1777 if (isOperandInFarSpace(IC_LEFT(dic)) ||
1778 isOperandInFarSpace(IC_RIGHT(dic)) ||
1779 IS_OP_RUONLY(IC_LEFT(ic)) ||
1780 IS_OP_RUONLY(IC_RIGHT(ic)) ) {
1784 /* if pointer set then make sure the pointer
1786 if (POINTER_SET(dic) &&
1787 !IS_DATA_PTR(aggrToPtr(operandType(IC_RESULT(dic)),FALSE)))
1790 if (POINTER_GET(dic) &&
1791 !IS_DATA_PTR(aggrToPtr(operandType(IC_LEFT(dic)),FALSE)))
1796 /* also make sure the intervenening instructions
1797 don't have any thing in far space */
1798 for (dic = dic->next ; dic && dic != ic && sic != ic; dic = dic->next) {
1800 /* if there is an intervening function call then no */
1801 if (dic->op == CALL || dic->op == PCALL)
1803 /* if pointer set then make sure the pointer
1805 if (POINTER_SET(dic) &&
1806 !IS_DATA_PTR(aggrToPtr(operandType(IC_RESULT(dic)),FALSE)))
1809 if (POINTER_GET(dic) &&
1810 !IS_DATA_PTR(aggrToPtr(operandType(IC_LEFT(dic)),FALSE)))
1813 /* if address of & the result is remat the okay */
1814 if (dic->op == ADDRESS_OF &&
1815 OP_SYMBOL(IC_RESULT(dic))->remat)
1818 /* if operand has size of three or more & this
1819 operation is a '*','/' or '%' then 'b' may
1821 if (( dic->op == '%' || dic->op == '/' || dic->op == '*') &&
1822 getSize(operandType(op)) >= 3)
1825 /* if left or right or result is in far space */
1826 if (isOperandInFarSpace(IC_LEFT(dic)) ||
1827 isOperandInFarSpace(IC_RIGHT(dic)) ||
1828 isOperandInFarSpace(IC_RESULT(dic)) ||
1829 IS_OP_RUONLY(IC_LEFT(dic)) ||
1830 IS_OP_RUONLY(IC_RIGHT(dic)) ||
1831 IS_OP_RUONLY(IC_RESULT(dic)) ) {
1836 OP_SYMBOL(op)->ruonly = 1;
1841 /*-----------------------------------------------------------------*/
1842 /* isBitwiseOptimizable - requirements of JEAN LOUIS VERN */
1843 /*-----------------------------------------------------------------*/
1844 static bool isBitwiseOptimizable (iCode *ic)
1846 link *ltype = getSpec(operandType(IC_LEFT(ic)));
1847 link *rtype = getSpec(operandType(IC_RIGHT(ic)));
1849 /* bitwise operations are considered optimizable
1850 under the following conditions (Jean-Louis VERN)
1862 if ( IS_LITERAL(rtype) ||
1863 (IS_BITVAR(ltype) && IN_BITSPACE(SPEC_OCLS(ltype))))
1869 /*-----------------------------------------------------------------*/
1870 /* packRegsForAccUse - pack registers for acc use */
1871 /*-----------------------------------------------------------------*/
1872 static void packRegsForAccUse (iCode *ic)
1876 /* if + or - then it has to be one byte result */
1877 if ((ic->op == '+' || ic->op == '-')
1878 && getSize(operandType(IC_RESULT(ic))) > 1)
1881 /* if shift operation make sure right side is not a literal */
1882 if (ic->op == RIGHT_OP &&
1883 ( isOperandLiteral(IC_RIGHT(ic)) ||
1884 getSize(operandType(IC_RESULT(ic))) > 1))
1887 if (ic->op == LEFT_OP &&
1888 ( isOperandLiteral(IC_RIGHT(ic)) ||
1889 getSize(operandType(IC_RESULT(ic))) > 1))
1892 if (IS_BITWISE_OP(ic) &&
1893 getSize(operandType(IC_RESULT(ic))) > 1)
1897 /* has only one definition */
1898 if (bitVectnBitsOn(OP_DEFS(IC_RESULT(ic))) > 1)
1901 /* has only one use */
1902 if (bitVectnBitsOn(OP_USES(IC_RESULT(ic))) > 1)
1905 /* and the usage immediately follows this iCode */
1906 if (!(uic = hTabItemWithKey(iCodehTab,
1907 bitVectFirstBit(OP_USES(IC_RESULT(ic))))))
1910 if (ic->next != uic)
1913 /* if it is a conditional branch then we definitely can */
1914 if (uic->op == IFX )
1917 if ( uic->op == JUMPTABLE )
1920 /* if the usage is not is an assignment
1921 or an arithmetic / bitwise / shift operation then not */
1922 if (POINTER_SET(uic) &&
1923 getSize(aggrToPtr(operandType(IC_RESULT(uic)),FALSE)) > 1)
1926 if (uic->op != '=' &&
1927 !IS_ARITHMETIC_OP(uic) &&
1928 !IS_BITWISE_OP(uic) &&
1929 uic->op != LEFT_OP &&
1930 uic->op != RIGHT_OP )
1933 /* if used in ^ operation then make sure right is not a
1935 if (uic->op == '^' && isOperandLiteral(IC_RIGHT(uic)))
1938 /* if shift operation make sure right side is not a literal */
1939 if (uic->op == RIGHT_OP &&
1940 ( isOperandLiteral(IC_RIGHT(uic)) ||
1941 getSize(operandType(IC_RESULT(uic))) > 1))
1944 if (uic->op == LEFT_OP &&
1945 ( isOperandLiteral(IC_RIGHT(uic)) ||
1946 getSize(operandType(IC_RESULT(uic))) > 1))
1949 /* make sure that the result of this icode is not on the
1950 stack, since acc is used to compute stack offset */
1951 if (IS_TRUE_SYMOP(IC_RESULT(uic)) &&
1952 OP_SYMBOL(IC_RESULT(uic))->onStack)
1955 /* if either one of them in far space then we cannot */
1956 if ((IS_TRUE_SYMOP(IC_LEFT(uic)) &&
1957 isOperandInFarSpace(IC_LEFT(uic))) ||
1958 (IS_TRUE_SYMOP(IC_RIGHT(uic)) &&
1959 isOperandInFarSpace(IC_RIGHT(uic))))
1962 /* if the usage has only one operand then we can */
1963 if (IC_LEFT(uic) == NULL ||
1964 IC_RIGHT(uic) == NULL)
1967 /* make sure this is on the left side if not
1968 a '+' since '+' is commutative */
1969 if (ic->op != '+' &&
1970 IC_LEFT(uic)->key != IC_RESULT(ic)->key)
1973 /* if one of them is a literal then we can */
1974 if ((IC_LEFT(uic) && IS_OP_LITERAL(IC_LEFT(uic))) ||
1975 (IC_RIGHT(uic) && IS_OP_LITERAL(IC_RIGHT(uic)))) {
1976 OP_SYMBOL(IC_RESULT(ic))->accuse = 1;
1980 /* if the other one is not on stack then we can */
1981 if (IC_LEFT(uic)->key == IC_RESULT(ic)->key &&
1982 (IS_ITEMP(IC_RIGHT(uic)) ||
1983 (IS_TRUE_SYMOP(IC_RIGHT(uic)) &&
1984 !OP_SYMBOL(IC_RIGHT(uic))->onStack)))
1987 if (IC_RIGHT(uic)->key == IC_RESULT(ic)->key &&
1988 (IS_ITEMP(IC_LEFT(uic)) ||
1989 (IS_TRUE_SYMOP(IC_LEFT(uic)) &&
1990 !OP_SYMBOL(IC_LEFT(uic))->onStack)))
1996 OP_SYMBOL(IC_RESULT(ic))->accuse = 1;
2001 /*-----------------------------------------------------------------*/
2002 /* packForPush - hueristics to reduce iCode for pushing */
2003 /*-----------------------------------------------------------------*/
2004 static void packForPush(iCode *ic, eBBlock *ebp)
2008 if (ic->op != IPUSH || !IS_ITEMP(IC_LEFT(ic)))
2011 /* must have only definition & one usage */
2012 if (bitVectnBitsOn(OP_DEFS(IC_LEFT(ic))) != 1 ||
2013 bitVectnBitsOn(OP_USES(IC_LEFT(ic))) != 1 )
2016 /* find the definition */
2017 if (!(dic = hTabItemWithKey(iCodehTab,
2018 bitVectFirstBit(OP_DEFS(IC_LEFT(ic))))))
2021 if (dic->op != '=' || POINTER_SET(dic))
2024 /* we now we know that it has one & only one def & use
2025 and the that the definition is an assignment */
2026 IC_LEFT(ic) = IC_RIGHT(dic);
2028 remiCodeFromeBBlock(ebp,dic);
2029 hTabDeleteItem (&iCodehTab,dic->key,dic,DELETE_ITEM,NULL);
2032 /*-----------------------------------------------------------------*/
2033 /* packRegisters - does some transformations to reduce register */
2035 /*-----------------------------------------------------------------*/
2036 static void packRegisters (eBBlock *ebp)
2045 /* look for assignments of the form */
2046 /* iTempNN = TRueSym (someoperation) SomeOperand */
2048 /* TrueSym := iTempNN:1 */
2049 for ( ic = ebp->sch ; ic ; ic = ic->next ) {
2052 /* find assignment of the form TrueSym := iTempNN:1 */
2053 if (ic->op == '=' && !POINTER_SET(ic))
2054 change += packRegsForAssign(ic,ebp);
2061 for ( ic = ebp->sch ; ic ; ic = ic->next ) {
2063 /* if this is an itemp & result of a address of a true sym
2064 then mark this as rematerialisable */
2065 if (ic->op == ADDRESS_OF &&
2066 IS_ITEMP(IC_RESULT(ic)) &&
2067 IS_TRUE_SYMOP(IC_LEFT(ic)) &&
2068 bitVectnBitsOn(OP_DEFS(IC_RESULT(ic))) == 1 &&
2069 !OP_SYMBOL(IC_LEFT(ic))->onStack ) {
2071 OP_SYMBOL(IC_RESULT(ic))->remat = 1;
2072 OP_SYMBOL(IC_RESULT(ic))->rematiCode = ic;
2073 OP_SYMBOL(IC_RESULT(ic))->usl.spillLoc = NULL;
2077 /* if straight assignment then carry remat flag if
2078 this is the only definition */
2079 if (ic->op == '=' &&
2081 IS_SYMOP(IC_RIGHT(ic)) &&
2082 OP_SYMBOL(IC_RIGHT(ic))->remat &&
2083 bitVectnBitsOn(OP_SYMBOL(IC_RESULT(ic))->defs) <= 1) {
2085 OP_SYMBOL(IC_RESULT(ic))->remat =
2086 OP_SYMBOL(IC_RIGHT(ic))->remat;
2087 OP_SYMBOL(IC_RESULT(ic))->rematiCode =
2088 OP_SYMBOL(IC_RIGHT(ic))->rematiCode ;
2091 /* if this is a +/- operation with a rematerizable
2092 then mark this as rematerializable as well */
2093 if ((ic->op == '+' || ic->op == '-') &&
2094 (IS_SYMOP(IC_LEFT(ic)) &&
2095 IS_ITEMP(IC_RESULT(ic)) &&
2096 OP_SYMBOL(IC_LEFT(ic))->remat &&
2097 bitVectnBitsOn(OP_DEFS(IC_RESULT(ic))) == 1 &&
2098 IS_OP_LITERAL(IC_RIGHT(ic))) ) {
2100 int i = operandLitValue(IC_RIGHT(ic));
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;
2106 /* mark the pointer usages */
2107 if (POINTER_SET(ic))
2108 OP_SYMBOL(IC_RESULT(ic))->uptr = 1;
2110 if (POINTER_GET(ic))
2111 OP_SYMBOL(IC_LEFT(ic))->uptr = 1;
2113 if (!SKIP_IC2(ic)) {
2114 /* if we are using a symbol on the stack
2115 then we should say mcs51_ptrRegReq */
2116 if (ic->op == IFX && IS_SYMOP(IC_COND(ic)))
2117 mcs51_ptrRegReq += ((OP_SYMBOL(IC_COND(ic))->onStack ||
2118 OP_SYMBOL(IC_COND(ic))->iaccess) ? 1 : 0);
2120 if (ic->op == JUMPTABLE && IS_SYMOP(IC_JTCOND(ic)))
2121 mcs51_ptrRegReq += ((OP_SYMBOL(IC_JTCOND(ic))->onStack ||
2122 OP_SYMBOL(IC_JTCOND(ic))->iaccess) ? 1 : 0);
2124 if (IS_SYMOP(IC_LEFT(ic)))
2125 mcs51_ptrRegReq += ((OP_SYMBOL(IC_LEFT(ic))->onStack ||
2126 OP_SYMBOL(IC_LEFT(ic))->iaccess) ? 1 : 0);
2127 if (IS_SYMOP(IC_RIGHT(ic)))
2128 mcs51_ptrRegReq += ((OP_SYMBOL(IC_RIGHT(ic))->onStack ||
2129 OP_SYMBOL(IC_RIGHT(ic))->iaccess) ? 1 : 0);
2130 if (IS_SYMOP(IC_RESULT(ic)))
2131 mcs51_ptrRegReq += ((OP_SYMBOL(IC_RESULT(ic))->onStack ||
2132 OP_SYMBOL(IC_RESULT(ic))->iaccess) ? 1 : 0);
2136 /* if the condition of an if instruction
2137 is defined in the previous instruction then
2138 mark the itemp as a conditional */
2139 if ((IS_CONDITIONAL(ic) ||
2140 ( ( ic->op == BITWISEAND ||
2143 isBitwiseOptimizable(ic))) &&
2144 ic->next && ic->next->op == IFX &&
2145 isOperandEqual(IC_RESULT(ic),IC_COND(ic->next)) &&
2146 OP_SYMBOL(IC_RESULT(ic))->liveTo <= ic->next->seq) {
2148 OP_SYMBOL(IC_RESULT(ic))->regType = REG_CND;
2152 /* reduce for support function calls */
2153 if (ic->supportRtn || ic->op == '+' || ic->op == '-' )
2154 packRegsForSupport (ic,ebp);
2156 /* some cases the redundant moves can
2157 can be eliminated for return statements */
2158 if ((ic->op == RETURN || ic->op == SEND) &&
2159 !isOperandInFarSpace(IC_LEFT(ic)) &&
2160 options.model == MODEL_SMALL)
2161 packRegsForOneuse (ic,IC_LEFT(ic),ebp);
2163 /* if pointer set & left has a size more than
2164 one and right is not in far space */
2165 if (POINTER_SET(ic) &&
2166 !isOperandInFarSpace(IC_RIGHT(ic)) &&
2167 !OP_SYMBOL(IC_RESULT(ic))->remat &&
2168 !IS_OP_RUONLY(IC_RIGHT(ic)) &&
2169 getSize(aggrToPtr(operandType(IC_RESULT(ic)),FALSE)) > 1 )
2171 packRegsForOneuse (ic,IC_RESULT(ic),ebp);
2173 /* if pointer get */
2174 if (POINTER_GET(ic) &&
2175 !isOperandInFarSpace(IC_RESULT(ic))&&
2176 !OP_SYMBOL(IC_LEFT(ic))->remat &&
2177 !IS_OP_RUONLY(IC_RESULT(ic)) &&
2178 getSize(aggrToPtr(operandType(IC_LEFT(ic)),FALSE)) > 1 )
2180 packRegsForOneuse (ic,IC_LEFT(ic),ebp);
2183 /* if this is cast for intergral promotion then
2184 check if only use of the definition of the
2185 operand being casted/ if yes then replace
2186 the result of that arithmetic operation with
2187 this result and get rid of the cast */
2188 if (ic->op == CAST) {
2189 link *fromType = operandType(IC_RIGHT(ic));
2190 link *toType = operandType(IC_LEFT(ic));
2192 if (IS_INTEGRAL(fromType) && IS_INTEGRAL(toType) &&
2193 getSize(fromType) != getSize(toType) &&
2194 SPEC_USIGN(fromType) == SPEC_USIGN(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);
2202 OP_DEFS(IC_RESULT(dic)) = bitVectSetBit(OP_DEFS(IC_RESULT(dic)),dic->key);
2205 OP_SYMBOL(IC_RIGHT(ic))->ruonly = 0;
2209 /* if the type from and type to are the same
2210 then if this is the only use then packit */
2211 if (checkType(operandType(IC_RIGHT(ic)),
2212 operandType(IC_LEFT(ic))) == 1) {
2213 iCode *dic = packRegsForOneuse (ic,IC_RIGHT(ic),ebp);
2215 IC_RESULT(dic) = IC_RESULT(ic);
2216 remiCodeFromeBBlock(ebp,ic);
2217 hTabDeleteItem (&iCodehTab,ic->key,ic,DELETE_ITEM,NULL);
2218 OP_DEFS(IC_RESULT(dic)) = bitVectSetBit(OP_DEFS(IC_RESULT(dic)),dic->key);
2226 iTempNN := (some variable in farspace) V1
2231 if (ic->op == IPUSH ) {
2232 packForPush(ic,ebp);
2236 /* pack registers for accumulator use, when the
2237 result of an arithmetic or bit wise operation
2238 has only one use, that use is immediately following
2239 the defintion and the using iCode has only one
2240 operand or has two operands but one is literal &
2241 the result of that operation is not on stack then
2242 we can leave the result of this operation in acc:b
2244 if ((IS_ARITHMETIC_OP(ic)
2245 || IS_BITWISE_OP(ic)
2246 || ic->op == LEFT_OP || ic->op == RIGHT_OP
2247 || (ic->op == ADDRESS_OF && isOperandOnStack(IC_LEFT(ic)))
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);
2311 dumpLiveRanges(".lrange",liveRanges);
2314 /* do the overlaysegment stuff SDCCmem.c */
2315 doOverlays(ebbs,count);
2317 /* now get back the chain */
2318 ic = iCodeLabelOptimize(iCodeFromeBBlock (ebbs,count));
2323 /* free up any _G.stackSpil locations allocated */
2324 applyToSet(_G.stackSpil,deallocStackSpil);
2326 setToNull((void **)&_G.stackSpil);
2327 setToNull((void **)&_G.spiltSet);
2328 /* mark all registers as free */