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) && IS_SYMOP(IC_LEFT(ic))
1080 && getSize(OP_SYMBOL(IC_LEFT(ic))->type)
1086 /* else we assign registers to it */
1087 _G.regAssigned = bitVectSetBit(_G.regAssigned,sym->key);
1089 for (j = 0 ; j < sym->nRegs ;j++ ) {
1090 if (sym->regType == REG_PTR)
1091 sym->regs[j] = getRegPtr(ic,ebbs[i],sym);
1093 sym->regs[j] = getRegGpr(ic,ebbs[i],sym);
1095 /* if the allocation falied which means
1096 this was spilt then break */
1100 /* if it shares registers with operands make sure
1101 that they are in the same position */
1102 if (IC_LEFT(ic) && IS_SYMOP(IC_LEFT(ic)) &&
1103 OP_SYMBOL(IC_LEFT(ic))->nRegs && ic->op != '=')
1104 positionRegs(OP_SYMBOL(IC_RESULT(ic)),
1105 OP_SYMBOL(IC_LEFT(ic)),ic->lineno);
1106 /* do the same for the right operand */
1107 if (IC_RIGHT(ic) && IS_SYMOP(IC_RIGHT(ic)) &&
1108 OP_SYMBOL(IC_RIGHT(ic))->nRegs)
1109 positionRegs(OP_SYMBOL(IC_RESULT(ic)),
1110 OP_SYMBOL(IC_RIGHT(ic)),ic->lineno);
1122 /*-----------------------------------------------------------------*/
1123 /* rUmaskForOp :- returns register mask for an operand */
1124 /*-----------------------------------------------------------------*/
1125 static bitVect *rUmaskForOp (operand *op)
1131 /* only temporaries are assigned registers */
1135 sym = OP_SYMBOL(op);
1137 /* if spilt or no registers assigned to it
1139 if (sym->isspilt || !sym->nRegs)
1142 rumask = newBitVect(mcs51_nRegs);
1144 for (j = 0; j < sym->nRegs; j++) {
1145 rumask = bitVectSetBit(rumask,
1146 sym->regs[j]->rIdx);
1152 /*-----------------------------------------------------------------*/
1153 /* regsUsedIniCode :- returns bit vector of registers used in iCode*/
1154 /*-----------------------------------------------------------------*/
1155 static bitVect *regsUsedIniCode (iCode *ic)
1157 bitVect *rmask = newBitVect(mcs51_nRegs);
1159 /* do the special cases first */
1160 if (ic->op == IFX ) {
1161 rmask = bitVectUnion(rmask,
1162 rUmaskForOp(IC_COND(ic)));
1166 /* for the jumptable */
1167 if (ic->op == JUMPTABLE) {
1168 rmask = bitVectUnion(rmask,
1169 rUmaskForOp(IC_JTCOND(ic)));
1174 /* of all other cases */
1176 rmask = bitVectUnion(rmask,
1177 rUmaskForOp(IC_LEFT(ic)));
1181 rmask = bitVectUnion(rmask,
1182 rUmaskForOp(IC_RIGHT(ic)));
1185 rmask = bitVectUnion(rmask,
1186 rUmaskForOp(IC_RESULT(ic)));
1192 /*-----------------------------------------------------------------*/
1193 /* createRegMask - for each instruction will determine the regsUsed*/
1194 /*-----------------------------------------------------------------*/
1195 static void createRegMask (eBBlock **ebbs, int count)
1199 /* for all blocks */
1200 for (i = 0; i < count ; i++ ) {
1203 if ( ebbs[i]->noPath &&
1204 ( ebbs[i]->entryLabel != entryLabel &&
1205 ebbs[i]->entryLabel != returnLabel ))
1208 /* for all instructions */
1209 for ( ic = ebbs[i]->sch ; ic ; ic = ic->next ) {
1213 if (SKIP_IC2(ic) || !ic->rlive)
1216 /* first mark the registers used in this
1218 ic->rUsed = regsUsedIniCode(ic);
1219 _G.funcrUsed = bitVectUnion(_G.funcrUsed,ic->rUsed);
1221 /* now create the register mask for those
1222 registers that are in use : this is a
1223 super set of ic->rUsed */
1224 ic->rMask = newBitVect(mcs51_nRegs+1);
1226 /* for all live Ranges alive at this point */
1227 for (j = 1; j < ic->rlive->size; j++ ) {
1231 /* if not alive then continue */
1232 if (!bitVectBitValue(ic->rlive,j))
1235 /* find the live range we are interested in */
1236 if (!(sym = hTabItemWithKey(liveRanges,j))) {
1237 werror (E_INTERNAL_ERROR,__FILE__,__LINE__,
1238 "createRegMask cannot find live range");
1242 /* if no register assigned to it */
1243 if (!sym->nRegs || sym->isspilt)
1246 /* for all the registers allocated to it */
1247 for (k = 0 ; k < sym->nRegs ;k++)
1250 bitVectSetBit(ic->rMask,sym->regs[k]->rIdx);
1256 /*-----------------------------------------------------------------*/
1257 /* rematStr - returns the rematerialized string for a remat var */
1258 /*-----------------------------------------------------------------*/
1259 static char *rematStr (symbol *sym)
1262 iCode *ic = sym->rematiCode;
1266 /* if plus or minus print the right hand side */
1267 if (ic->op == '+' || ic->op == '-') {
1268 sprintf(s,"0x%04x %c ",(int) operandLitValue(IC_RIGHT(ic)),
1271 ic = OP_SYMBOL(IC_LEFT(ic))->rematiCode;
1275 /* we reached the end */
1276 sprintf(s,"%s",OP_SYMBOL(IC_LEFT(ic))->rname);
1283 /*-----------------------------------------------------------------*/
1284 /* regTypeNum - computes the type & number of registers required */
1285 /*-----------------------------------------------------------------*/
1286 static void regTypeNum ()
1292 /* for each live range do */
1293 for ( sym = hTabFirstItem(liveRanges,&k); sym ;
1294 sym = hTabNextItem(liveRanges,&k)) {
1296 /* if used zero times then no registers needed */
1297 if ((sym->liveTo - sym->liveFrom) == 0)
1301 /* if the live range is a temporary */
1304 /* if the type is marked as a conditional */
1305 if (sym->regType == REG_CND)
1308 /* if used in return only then we don't
1310 if (sym->ruonly || sym->accuse) {
1311 if (IS_AGGREGATE(sym->type) || sym->isptr)
1312 sym->type = aggrToPtr(sym->type,FALSE);
1316 /* if the symbol has only one definition &
1317 that definition is a get_pointer and the
1318 pointer we are getting is rematerializable and
1321 if (bitVectnBitsOn(sym->defs) == 1 &&
1322 (ic = hTabItemWithKey(iCodehTab,
1323 bitVectFirstBit(sym->defs))) &&
1325 !IS_BITVAR(sym->etype)) {
1328 /* if remat in data space */
1329 if (OP_SYMBOL(IC_LEFT(ic))->remat &&
1330 DCL_TYPE(aggrToPtr(sym->type,FALSE)) == POINTER) {
1332 /* create a psuedo symbol & force a spil */
1333 symbol *psym = newSymbol(rematStr(OP_SYMBOL(IC_LEFT(ic))),1);
1334 psym->type = sym->type;
1335 psym->etype = sym->etype;
1336 strcpy(psym->rname,psym->name);
1338 sym->usl.spillLoc = psym;
1342 /* if in data space or idata space then try to
1343 allocate pointer register */
1347 /* if not then we require registers */
1348 sym->nRegs = ((IS_AGGREGATE(sym->type) || sym->isptr ) ?
1349 getSize(sym->type = aggrToPtr(sym->type,FALSE)) :
1350 getSize(sym->type));
1352 if (sym->nRegs > 4) {
1353 fprintf(stderr,"allocated more than 4 or 0 registers for type ");
1354 printTypeChain(sym->type,stderr);fprintf(stderr,"\n");
1357 /* determine the type of register required */
1358 if (sym->nRegs == 1 &&
1359 IS_PTR(sym->type) &&
1361 sym->regType = REG_PTR ;
1363 sym->regType = REG_GPR ;
1366 /* for the first run we don't provide */
1367 /* registers for true symbols we will */
1368 /* see how things go */
1374 /*-----------------------------------------------------------------*/
1375 /* freeAllRegs - mark all registers as free */
1376 /*-----------------------------------------------------------------*/
1377 static void freeAllRegs()
1381 for (i=0;i< mcs51_nRegs;i++ )
1382 regs8051[i].isFree = 1;
1385 /*-----------------------------------------------------------------*/
1386 /* deallocStackSpil - this will set the stack pointer back */
1387 /*-----------------------------------------------------------------*/
1388 static DEFSETFUNC(deallocStackSpil)
1396 /*-----------------------------------------------------------------*/
1397 /* farSpacePackable - returns the packable icode for far variables */
1398 /*-----------------------------------------------------------------*/
1399 static iCode *farSpacePackable (iCode *ic)
1403 /* go thru till we find a definition for the
1404 symbol on the right */
1405 for ( dic = ic->prev ; dic ; dic = dic->prev) {
1407 /* if the definition is a call then no */
1408 if ((dic->op == CALL || dic->op == PCALL) &&
1409 IC_RESULT(dic)->key == IC_RIGHT(ic)->key) {
1413 /* if shift by unknown amount then not */
1414 if ((dic->op == LEFT_OP || dic->op == RIGHT_OP) &&
1415 IC_RESULT(dic)->key == IC_RIGHT(ic)->key)
1418 /* if pointer get and size > 1 */
1419 if (POINTER_GET(dic) &&
1420 getSize(aggrToPtr(operandType(IC_LEFT(dic)),FALSE)) > 1)
1423 if (POINTER_SET(dic) &&
1424 getSize(aggrToPtr(operandType(IC_RESULT(dic)),FALSE)) > 1)
1427 /* if any three is a true symbol in far space */
1428 if (IC_RESULT(dic) &&
1429 IS_TRUE_SYMOP(IC_RESULT(dic)) &&
1430 isOperandInFarSpace(IC_RESULT(dic)))
1433 if (IC_RIGHT(dic) &&
1434 IS_TRUE_SYMOP(IC_RIGHT(dic)) &&
1435 isOperandInFarSpace(IC_RIGHT(dic)) &&
1436 !isOperandEqual(IC_RIGHT(dic),IC_RESULT(ic)))
1440 IS_TRUE_SYMOP(IC_LEFT(dic)) &&
1441 isOperandInFarSpace(IC_LEFT(dic)) &&
1442 !isOperandEqual(IC_LEFT(dic),IC_RESULT(ic)))
1445 if (isOperandEqual(IC_RIGHT(ic),IC_RESULT(dic))) {
1446 if ( (dic->op == LEFT_OP ||
1447 dic->op == RIGHT_OP ||
1449 IS_OP_LITERAL(IC_RIGHT(dic)))
1459 /*-----------------------------------------------------------------*/
1460 /* packRegsForAssign - register reduction for assignment */
1461 /*-----------------------------------------------------------------*/
1462 static int packRegsForAssign (iCode *ic,eBBlock *ebp)
1465 sym_link *etype = operandType(IC_RIGHT(ic));
1467 if (!IS_ITEMP(IC_RIGHT(ic)) ||
1468 OP_SYMBOL(IC_RIGHT(ic))->isind ||
1469 OP_LIVETO(IC_RIGHT(ic)) > ic->seq ||
1470 IS_BITFIELD(etype)) {
1474 /* if the true symbol is defined in far space or on stack
1475 then we should not since this will increase register pressure */
1476 if (isOperandInFarSpace(IC_RESULT(ic))) {
1477 if ((dic = farSpacePackable(ic)))
1483 /* find the definition of iTempNN scanning backwards if we find a
1484 a use of the true symbol in before we find the definition then
1486 for ( dic = ic->prev ; dic ; dic = dic->prev) {
1488 /* if there is a function call and this is
1489 a parameter & not my parameter then don't pack it */
1490 if ( (dic->op == CALL || dic->op == PCALL) &&
1491 (OP_SYMBOL(IC_RESULT(ic))->_isparm &&
1492 !OP_SYMBOL(IC_RESULT(ic))->ismyparm)) {
1500 if (IS_TRUE_SYMOP(IC_RESULT(dic)) &&
1501 IS_OP_VOLATILE(IC_RESULT(dic))) {
1506 if (IS_SYMOP(IC_RESULT(dic)) &&
1507 IC_RESULT(dic)->key == IC_RIGHT(ic)->key) {
1508 if (POINTER_SET(dic))
1514 if (IS_SYMOP(IC_RIGHT(dic)) &&
1515 (IC_RIGHT(dic)->key == IC_RESULT(ic)->key ||
1516 IC_RIGHT(dic)->key == IC_RIGHT(ic)->key)) {
1521 if (IS_SYMOP(IC_LEFT(dic)) &&
1522 (IC_LEFT(dic)->key == IC_RESULT(ic)->key ||
1523 IC_LEFT(dic)->key == IC_RIGHT(ic)->key)) {
1528 if (POINTER_SET(dic) &&
1529 IC_RESULT(dic)->key == IC_RESULT(ic)->key ) {
1536 return 0 ; /* did not find */
1538 /* if assignment then check that right is not a bit */
1539 if (ASSIGNMENT(dic) && !POINTER_SET(dic)) {
1540 sym_link *etype = operandType(IC_RIGHT(dic));
1541 if (IS_BITFIELD(etype)) return 0;
1543 /* if the result is on stack or iaccess then it must be
1544 the same atleast one of the operands */
1545 if (OP_SYMBOL(IC_RESULT(ic))->onStack ||
1546 OP_SYMBOL(IC_RESULT(ic))->iaccess ) {
1548 /* the operation has only one symbol
1549 operator then we can pack */
1550 if ((IC_LEFT(dic) && !IS_SYMOP(IC_LEFT(dic))) ||
1551 (IC_RIGHT(dic) && !IS_SYMOP(IC_RIGHT(dic))))
1554 if (!((IC_LEFT(dic) &&
1555 IC_RESULT(ic)->key == IC_LEFT(dic)->key) ||
1557 IC_RESULT(ic)->key == IC_RIGHT(dic)->key)))
1561 /* found the definition */
1562 /* replace the result with the result of */
1563 /* this assignment and remove this assignment */
1564 IC_RESULT(dic) = IC_RESULT(ic) ;
1566 if (IS_ITEMP(IC_RESULT(dic)) && OP_SYMBOL(IC_RESULT(dic))->liveFrom > dic->seq) {
1567 OP_SYMBOL(IC_RESULT(dic))->liveFrom = dic->seq;
1569 /* delete from liverange table also
1570 delete from all the points inbetween and the new
1572 for ( sic = dic; sic != ic ; sic = sic->next ) {
1573 bitVectUnSetBit(sic->rlive,IC_RESULT(ic)->key);
1574 if (IS_ITEMP(IC_RESULT(dic)))
1575 bitVectSetBit(sic->rlive,IC_RESULT(dic)->key);
1578 remiCodeFromeBBlock(ebp,ic);
1579 hTabDeleteItem (&iCodehTab,ic->key,ic,DELETE_ITEM,NULL);
1580 OP_DEFS(IC_RESULT(dic)) = bitVectSetBit(OP_DEFS(IC_RESULT(dic)),dic->key);
1585 /*-----------------------------------------------------------------*/
1586 /* findAssignToSym : scanning backwards looks for first assig found*/
1587 /*-----------------------------------------------------------------*/
1588 static iCode *findAssignToSym (operand *op,iCode *ic)
1592 for (dic = ic->prev ; dic ; dic = dic->prev) {
1594 /* if definition by assignment */
1595 if (dic->op == '=' &&
1596 !POINTER_SET(dic) &&
1597 IC_RESULT(dic)->key == op->key
1598 /* && IS_TRUE_SYMOP(IC_RIGHT(dic)) */
1601 /* we are interested only if defined in far space */
1602 /* or in stack space in case of + & - */
1604 /* if assigned to a non-symbol then return
1606 if (!IS_SYMOP(IC_RIGHT(dic)))
1609 /* if the symbol is in far space then
1611 if (isOperandInFarSpace(IC_RIGHT(dic)))
1614 /* for + & - operations make sure that
1615 if it is on the stack it is the same
1616 as one of the three operands */
1617 if ((ic->op == '+' || ic->op == '-') &&
1618 OP_SYMBOL(IC_RIGHT(dic))->onStack) {
1620 if ( IC_RESULT(ic)->key != IC_RIGHT(dic)->key &&
1621 IC_LEFT(ic)->key != IC_RIGHT(dic)->key &&
1622 IC_RIGHT(ic)->key != IC_RIGHT(dic)->key)
1630 /* if we find an usage then we cannot delete it */
1631 if (IC_LEFT(dic) && IC_LEFT(dic)->key == op->key)
1634 if (IC_RIGHT(dic) && IC_RIGHT(dic)->key == op->key)
1637 if (POINTER_SET(dic) && IC_RESULT(dic)->key == op->key)
1641 /* now make sure that the right side of dic
1642 is not defined between ic & dic */
1644 iCode *sic = dic->next ;
1646 for (; sic != ic ; sic = sic->next)
1647 if (IC_RESULT(sic) &&
1648 IC_RESULT(sic)->key == IC_RIGHT(dic)->key)
1657 /*-----------------------------------------------------------------*/
1658 /* packRegsForSupport :- reduce some registers for support calls */
1659 /*-----------------------------------------------------------------*/
1660 static int packRegsForSupport (iCode *ic, eBBlock *ebp)
1663 /* for the left & right operand :- look to see if the
1664 left was assigned a true symbol in far space in that
1665 case replace them */
1666 if (IS_ITEMP(IC_LEFT(ic)) &&
1667 OP_SYMBOL(IC_LEFT(ic))->liveTo <= ic->seq) {
1668 iCode *dic = findAssignToSym(IC_LEFT(ic),ic);
1674 /* found it we need to remove it from the
1676 for ( sic = dic; sic != ic ; sic = sic->next )
1677 bitVectUnSetBit(sic->rlive,IC_LEFT(ic)->key);
1679 IC_LEFT(ic)->operand.symOperand =
1680 IC_RIGHT(dic)->operand.symOperand;
1681 IC_LEFT(ic)->key = IC_RIGHT(dic)->operand.symOperand->key;
1682 remiCodeFromeBBlock(ebp,dic);
1683 hTabDeleteItem (&iCodehTab,dic->key,dic,DELETE_ITEM,NULL);
1687 /* do the same for the right operand */
1690 IS_ITEMP(IC_RIGHT(ic)) &&
1691 OP_SYMBOL(IC_RIGHT(ic))->liveTo <= ic->seq) {
1692 iCode *dic = findAssignToSym(IC_RIGHT(ic),ic);
1698 /* if this is a subtraction & the result
1699 is a true symbol in far space then don't pack */
1700 if (ic->op == '-' && IS_TRUE_SYMOP(IC_RESULT(dic))) {
1701 sym_link *etype =getSpec(operandType(IC_RESULT(dic)));
1702 if (IN_FARSPACE(SPEC_OCLS(etype)))
1705 /* found it we need to remove it from the
1707 for ( sic = dic; sic != ic ; sic = sic->next )
1708 bitVectUnSetBit(sic->rlive,IC_RIGHT(ic)->key);
1710 IC_RIGHT(ic)->operand.symOperand =
1711 IC_RIGHT(dic)->operand.symOperand;
1712 IC_RIGHT(ic)->key = IC_RIGHT(dic)->operand.symOperand->key;
1714 remiCodeFromeBBlock(ebp,dic);
1715 hTabDeleteItem (&iCodehTab,dic->key,dic,DELETE_ITEM,NULL);
1722 #define IS_OP_RUONLY(x) (x && IS_SYMOP(x) && OP_SYMBOL(x)->ruonly)
1725 /*-----------------------------------------------------------------*/
1726 /* packRegsForOneuse : - will reduce some registers for single Use */
1727 /*-----------------------------------------------------------------*/
1728 static iCode *packRegsForOneuse (iCode *ic, operand *op , eBBlock *ebp)
1733 /* if returning a literal then do nothing */
1737 /* only upto 2 bytes since we cannot predict
1738 the usage of b, & acc */
1739 if (getSize(operandType(op)) > (fReturnSize - 2) &&
1746 /* this routine will mark the a symbol as used in one
1747 instruction use only && if the defintion is local
1748 (ie. within the basic block) && has only one definition &&
1749 that definiion is either a return value from a
1750 function or does not contain any variables in
1752 uses = bitVectCopy(OP_USES(op));
1753 bitVectUnSetBit(uses,ic->key); /* take away this iCode */
1754 if (!bitVectIsZero(uses)) /* has other uses */
1757 /* if it has only one defintion */
1758 if (bitVectnBitsOn(OP_DEFS(op)) > 1)
1759 return NULL ; /* has more than one definition */
1761 /* get the that definition */
1763 hTabItemWithKey(iCodehTab,
1764 bitVectFirstBit(OP_DEFS(op)))))
1767 /* found the definition now check if it is local */
1768 if (dic->seq < ebp->fSeq ||
1769 dic->seq > ebp->lSeq)
1770 return NULL ; /* non-local */
1772 /* now check if it is the return from
1774 if (dic->op == CALL || dic->op == PCALL ) {
1775 if (ic->op != SEND && ic->op != RETURN) {
1776 OP_SYMBOL(op)->ruonly = 1;
1783 /* otherwise check that the definition does
1784 not contain any symbols in far space */
1785 if (isOperandInFarSpace(IC_LEFT(dic)) ||
1786 isOperandInFarSpace(IC_RIGHT(dic)) ||
1787 IS_OP_RUONLY(IC_LEFT(ic)) ||
1788 IS_OP_RUONLY(IC_RIGHT(ic)) ) {
1792 /* if pointer set then make sure the pointer
1794 if (POINTER_SET(dic) &&
1795 !IS_DATA_PTR(aggrToPtr(operandType(IC_RESULT(dic)),FALSE)))
1798 if (POINTER_GET(dic) &&
1799 !IS_DATA_PTR(aggrToPtr(operandType(IC_LEFT(dic)),FALSE)))
1804 /* also make sure the intervenening instructions
1805 don't have any thing in far space */
1806 for (dic = dic->next ; dic && dic != ic && sic != ic; dic = dic->next) {
1808 /* if there is an intervening function call then no */
1809 if (dic->op == CALL || dic->op == PCALL)
1811 /* if pointer set then make sure the pointer
1813 if (POINTER_SET(dic) &&
1814 !IS_DATA_PTR(aggrToPtr(operandType(IC_RESULT(dic)),FALSE)))
1817 if (POINTER_GET(dic) &&
1818 !IS_DATA_PTR(aggrToPtr(operandType(IC_LEFT(dic)),FALSE)))
1821 /* if address of & the result is remat the okay */
1822 if (dic->op == ADDRESS_OF &&
1823 OP_SYMBOL(IC_RESULT(dic))->remat)
1826 /* if operand has size of three or more & this
1827 operation is a '*','/' or '%' then 'b' may
1829 if (( dic->op == '%' || dic->op == '/' || dic->op == '*') &&
1830 getSize(operandType(op)) >= 3)
1833 /* if left or right or result is in far space */
1834 if (isOperandInFarSpace(IC_LEFT(dic)) ||
1835 isOperandInFarSpace(IC_RIGHT(dic)) ||
1836 isOperandInFarSpace(IC_RESULT(dic)) ||
1837 IS_OP_RUONLY(IC_LEFT(dic)) ||
1838 IS_OP_RUONLY(IC_RIGHT(dic)) ||
1839 IS_OP_RUONLY(IC_RESULT(dic)) ) {
1844 OP_SYMBOL(op)->ruonly = 1;
1849 /*-----------------------------------------------------------------*/
1850 /* isBitwiseOptimizable - requirements of JEAN LOUIS VERN */
1851 /*-----------------------------------------------------------------*/
1852 static bool isBitwiseOptimizable (iCode *ic)
1854 sym_link *ltype = getSpec(operandType(IC_LEFT(ic)));
1855 sym_link *rtype = getSpec(operandType(IC_RIGHT(ic)));
1857 /* bitwise operations are considered optimizable
1858 under the following conditions (Jean-Louis VERN)
1870 if ( IS_LITERAL(rtype) ||
1871 (IS_BITVAR(ltype) && IN_BITSPACE(SPEC_OCLS(ltype))))
1877 /*-----------------------------------------------------------------*/
1878 /* packRegsForAccUse - pack registers for acc use */
1879 /*-----------------------------------------------------------------*/
1880 static void packRegsForAccUse (iCode *ic)
1884 /* if + or - then it has to be one byte result */
1885 if ((ic->op == '+' || ic->op == '-')
1886 && getSize(operandType(IC_RESULT(ic))) > 1)
1889 /* if shift operation make sure right side is not a literal */
1890 if (ic->op == RIGHT_OP &&
1891 ( isOperandLiteral(IC_RIGHT(ic)) ||
1892 getSize(operandType(IC_RESULT(ic))) > 1))
1895 if (ic->op == LEFT_OP &&
1896 ( isOperandLiteral(IC_RIGHT(ic)) ||
1897 getSize(operandType(IC_RESULT(ic))) > 1))
1900 if (IS_BITWISE_OP(ic) &&
1901 getSize(operandType(IC_RESULT(ic))) > 1)
1905 /* has only one definition */
1906 if (bitVectnBitsOn(OP_DEFS(IC_RESULT(ic))) > 1)
1909 /* has only one use */
1910 if (bitVectnBitsOn(OP_USES(IC_RESULT(ic))) > 1)
1913 /* and the usage immediately follows this iCode */
1914 if (!(uic = hTabItemWithKey(iCodehTab,
1915 bitVectFirstBit(OP_USES(IC_RESULT(ic))))))
1918 if (ic->next != uic)
1921 /* if it is a conditional branch then we definitely can */
1922 if (uic->op == IFX )
1925 if ( uic->op == JUMPTABLE )
1928 /* if the usage is not is an assignment
1929 or an arithmetic / bitwise / shift operation then not */
1930 if (POINTER_SET(uic) &&
1931 getSize(aggrToPtr(operandType(IC_RESULT(uic)),FALSE)) > 1)
1934 if (uic->op != '=' &&
1935 !IS_ARITHMETIC_OP(uic) &&
1936 !IS_BITWISE_OP(uic) &&
1937 uic->op != LEFT_OP &&
1938 uic->op != RIGHT_OP )
1941 /* if used in ^ operation then make sure right is not a
1943 if (uic->op == '^' && isOperandLiteral(IC_RIGHT(uic)))
1946 /* if shift operation make sure right side is not a literal */
1947 if (uic->op == RIGHT_OP &&
1948 ( isOperandLiteral(IC_RIGHT(uic)) ||
1949 getSize(operandType(IC_RESULT(uic))) > 1))
1952 if (uic->op == LEFT_OP &&
1953 ( isOperandLiteral(IC_RIGHT(uic)) ||
1954 getSize(operandType(IC_RESULT(uic))) > 1))
1957 /* make sure that the result of this icode is not on the
1958 stack, since acc is used to compute stack offset */
1959 if (IS_TRUE_SYMOP(IC_RESULT(uic)) &&
1960 OP_SYMBOL(IC_RESULT(uic))->onStack)
1963 /* if either one of them in far space then we cannot */
1964 if ((IS_TRUE_SYMOP(IC_LEFT(uic)) &&
1965 isOperandInFarSpace(IC_LEFT(uic))) ||
1966 (IS_TRUE_SYMOP(IC_RIGHT(uic)) &&
1967 isOperandInFarSpace(IC_RIGHT(uic))))
1970 /* if the usage has only one operand then we can */
1971 if (IC_LEFT(uic) == NULL ||
1972 IC_RIGHT(uic) == NULL)
1975 /* make sure this is on the left side if not
1976 a '+' since '+' is commutative */
1977 if (ic->op != '+' &&
1978 IC_LEFT(uic)->key != IC_RESULT(ic)->key)
1981 /* if one of them is a literal then we can */
1982 if ((IC_LEFT(uic) && IS_OP_LITERAL(IC_LEFT(uic))) ||
1983 (IC_RIGHT(uic) && IS_OP_LITERAL(IC_RIGHT(uic)))) {
1984 OP_SYMBOL(IC_RESULT(ic))->accuse = 1;
1988 /* if the other one is not on stack then we can */
1989 if (IC_LEFT(uic)->key == IC_RESULT(ic)->key &&
1990 (IS_ITEMP(IC_RIGHT(uic)) ||
1991 (IS_TRUE_SYMOP(IC_RIGHT(uic)) &&
1992 !OP_SYMBOL(IC_RIGHT(uic))->onStack)))
1995 if (IC_RIGHT(uic)->key == IC_RESULT(ic)->key &&
1996 (IS_ITEMP(IC_LEFT(uic)) ||
1997 (IS_TRUE_SYMOP(IC_LEFT(uic)) &&
1998 !OP_SYMBOL(IC_LEFT(uic))->onStack)))
2004 OP_SYMBOL(IC_RESULT(ic))->accuse = 1;
2009 /*-----------------------------------------------------------------*/
2010 /* packForPush - hueristics to reduce iCode for pushing */
2011 /*-----------------------------------------------------------------*/
2012 static void packForPush(iCode *ic, eBBlock *ebp)
2016 if (ic->op != IPUSH || !IS_ITEMP(IC_LEFT(ic)))
2019 /* must have only definition & one usage */
2020 if (bitVectnBitsOn(OP_DEFS(IC_LEFT(ic))) != 1 ||
2021 bitVectnBitsOn(OP_USES(IC_LEFT(ic))) != 1 )
2024 /* find the definition */
2025 if (!(dic = hTabItemWithKey(iCodehTab,
2026 bitVectFirstBit(OP_DEFS(IC_LEFT(ic))))))
2029 if (dic->op != '=' || POINTER_SET(dic))
2032 /* we now we know that it has one & only one def & use
2033 and the that the definition is an assignment */
2034 IC_LEFT(ic) = IC_RIGHT(dic);
2036 remiCodeFromeBBlock(ebp,dic);
2037 hTabDeleteItem (&iCodehTab,dic->key,dic,DELETE_ITEM,NULL);
2040 /*-----------------------------------------------------------------*/
2041 /* packRegisters - does some transformations to reduce register */
2043 /*-----------------------------------------------------------------*/
2044 static void packRegisters (eBBlock *ebp)
2053 /* look for assignments of the form */
2054 /* iTempNN = TRueSym (someoperation) SomeOperand */
2056 /* TrueSym := iTempNN:1 */
2057 for ( ic = ebp->sch ; ic ; ic = ic->next ) {
2060 /* find assignment of the form TrueSym := iTempNN:1 */
2061 if (ic->op == '=' && !POINTER_SET(ic))
2062 change += packRegsForAssign(ic,ebp);
2069 for ( ic = ebp->sch ; ic ; ic = ic->next ) {
2071 /* if this is an itemp & result of a address of a true sym
2072 then mark this as rematerialisable */
2073 if (ic->op == ADDRESS_OF &&
2074 IS_ITEMP(IC_RESULT(ic)) &&
2075 IS_TRUE_SYMOP(IC_LEFT(ic)) &&
2076 bitVectnBitsOn(OP_DEFS(IC_RESULT(ic))) == 1 &&
2077 !OP_SYMBOL(IC_LEFT(ic))->onStack ) {
2079 OP_SYMBOL(IC_RESULT(ic))->remat = 1;
2080 OP_SYMBOL(IC_RESULT(ic))->rematiCode = ic;
2081 OP_SYMBOL(IC_RESULT(ic))->usl.spillLoc = NULL;
2085 /* if straight assignment then carry remat flag if
2086 this is the only definition */
2087 if (ic->op == '=' &&
2089 IS_SYMOP(IC_RIGHT(ic)) &&
2090 OP_SYMBOL(IC_RIGHT(ic))->remat &&
2091 bitVectnBitsOn(OP_SYMBOL(IC_RESULT(ic))->defs) <= 1) {
2093 OP_SYMBOL(IC_RESULT(ic))->remat =
2094 OP_SYMBOL(IC_RIGHT(ic))->remat;
2095 OP_SYMBOL(IC_RESULT(ic))->rematiCode =
2096 OP_SYMBOL(IC_RIGHT(ic))->rematiCode ;
2099 /* if this is a +/- operation with a rematerizable
2100 then mark this as rematerializable as well */
2101 if ((ic->op == '+' || ic->op == '-') &&
2102 (IS_SYMOP(IC_LEFT(ic)) &&
2103 IS_ITEMP(IC_RESULT(ic)) &&
2104 OP_SYMBOL(IC_LEFT(ic))->remat &&
2105 bitVectnBitsOn(OP_DEFS(IC_RESULT(ic))) == 1 &&
2106 IS_OP_LITERAL(IC_RIGHT(ic))) ) {
2108 int i = operandLitValue(IC_RIGHT(ic));
2109 OP_SYMBOL(IC_RESULT(ic))->remat = 1;
2110 OP_SYMBOL(IC_RESULT(ic))->rematiCode = ic;
2111 OP_SYMBOL(IC_RESULT(ic))->usl.spillLoc = NULL;
2114 /* mark the pointer usages */
2115 if (POINTER_SET(ic))
2116 OP_SYMBOL(IC_RESULT(ic))->uptr = 1;
2118 if (POINTER_GET(ic))
2119 OP_SYMBOL(IC_LEFT(ic))->uptr = 1;
2121 if (!SKIP_IC2(ic)) {
2122 /* if we are using a symbol on the stack
2123 then we should say mcs51_ptrRegReq */
2124 if (ic->op == IFX && IS_SYMOP(IC_COND(ic)))
2125 mcs51_ptrRegReq += ((OP_SYMBOL(IC_COND(ic))->onStack ||
2126 OP_SYMBOL(IC_COND(ic))->iaccess) ? 1 : 0);
2128 if (ic->op == JUMPTABLE && IS_SYMOP(IC_JTCOND(ic)))
2129 mcs51_ptrRegReq += ((OP_SYMBOL(IC_JTCOND(ic))->onStack ||
2130 OP_SYMBOL(IC_JTCOND(ic))->iaccess) ? 1 : 0);
2132 if (IS_SYMOP(IC_LEFT(ic)))
2133 mcs51_ptrRegReq += ((OP_SYMBOL(IC_LEFT(ic))->onStack ||
2134 OP_SYMBOL(IC_LEFT(ic))->iaccess) ? 1 : 0);
2135 if (IS_SYMOP(IC_RIGHT(ic)))
2136 mcs51_ptrRegReq += ((OP_SYMBOL(IC_RIGHT(ic))->onStack ||
2137 OP_SYMBOL(IC_RIGHT(ic))->iaccess) ? 1 : 0);
2138 if (IS_SYMOP(IC_RESULT(ic)))
2139 mcs51_ptrRegReq += ((OP_SYMBOL(IC_RESULT(ic))->onStack ||
2140 OP_SYMBOL(IC_RESULT(ic))->iaccess) ? 1 : 0);
2144 /* if the condition of an if instruction
2145 is defined in the previous instruction then
2146 mark the itemp as a conditional */
2147 if ((IS_CONDITIONAL(ic) ||
2148 ( ( ic->op == BITWISEAND ||
2151 isBitwiseOptimizable(ic))) &&
2152 ic->next && ic->next->op == IFX &&
2153 isOperandEqual(IC_RESULT(ic),IC_COND(ic->next)) &&
2154 OP_SYMBOL(IC_RESULT(ic))->liveTo <= ic->next->seq) {
2156 OP_SYMBOL(IC_RESULT(ic))->regType = REG_CND;
2160 /* reduce for support function calls */
2161 if (ic->supportRtn || ic->op == '+' || ic->op == '-' )
2162 packRegsForSupport (ic,ebp);
2164 /* some cases the redundant moves can
2165 can be eliminated for return statements */
2166 if ((ic->op == RETURN || ic->op == SEND) &&
2167 !isOperandInFarSpace(IC_LEFT(ic)) &&
2168 options.model == MODEL_SMALL)
2169 packRegsForOneuse (ic,IC_LEFT(ic),ebp);
2171 /* if pointer set & left has a size more than
2172 one and right is not in far space */
2173 if (POINTER_SET(ic) &&
2174 !isOperandInFarSpace(IC_RIGHT(ic)) &&
2175 !OP_SYMBOL(IC_RESULT(ic))->remat &&
2176 !IS_OP_RUONLY(IC_RIGHT(ic)) &&
2177 getSize(aggrToPtr(operandType(IC_RESULT(ic)),FALSE)) > 1 )
2179 packRegsForOneuse (ic,IC_RESULT(ic),ebp);
2181 /* if pointer get */
2182 if (POINTER_GET(ic) &&
2183 !isOperandInFarSpace(IC_RESULT(ic))&&
2184 !OP_SYMBOL(IC_LEFT(ic))->remat &&
2185 !IS_OP_RUONLY(IC_RESULT(ic)) &&
2186 getSize(aggrToPtr(operandType(IC_LEFT(ic)),FALSE)) > 1 )
2188 packRegsForOneuse (ic,IC_LEFT(ic),ebp);
2191 /* if this is cast for intergral promotion then
2192 check if only use of the definition of the
2193 operand being casted/ if yes then replace
2194 the result of that arithmetic operation with
2195 this result and get rid of the cast */
2196 if (ic->op == CAST) {
2197 sym_link *fromType = operandType(IC_RIGHT(ic));
2198 sym_link *toType = operandType(IC_LEFT(ic));
2200 if (IS_INTEGRAL(fromType) && IS_INTEGRAL(toType) &&
2201 getSize(fromType) != getSize(toType) &&
2202 SPEC_USIGN(fromType) == SPEC_USIGN(toType)) {
2204 iCode *dic = packRegsForOneuse(ic,IC_RIGHT(ic),ebp);
2206 if (IS_ARITHMETIC_OP(dic)) {
2207 IC_RESULT(dic) = IC_RESULT(ic);
2208 remiCodeFromeBBlock(ebp,ic);
2209 hTabDeleteItem (&iCodehTab,ic->key,ic,DELETE_ITEM,NULL);
2210 OP_DEFS(IC_RESULT(dic)) = bitVectSetBit(OP_DEFS(IC_RESULT(dic)),dic->key);
2213 OP_SYMBOL(IC_RIGHT(ic))->ruonly = 0;
2217 /* if the type from and type to are the same
2218 then if this is the only use then packit */
2219 if (checkType(operandType(IC_RIGHT(ic)),
2220 operandType(IC_LEFT(ic))) == 1) {
2221 iCode *dic = packRegsForOneuse (ic,IC_RIGHT(ic),ebp);
2223 IC_RESULT(dic) = IC_RESULT(ic);
2224 remiCodeFromeBBlock(ebp,ic);
2225 hTabDeleteItem (&iCodehTab,ic->key,ic,DELETE_ITEM,NULL);
2226 OP_DEFS(IC_RESULT(dic)) = bitVectSetBit(OP_DEFS(IC_RESULT(dic)),dic->key);
2234 iTempNN := (some variable in farspace) V1
2239 if (ic->op == IPUSH ) {
2240 packForPush(ic,ebp);
2244 /* pack registers for accumulator use, when the
2245 result of an arithmetic or bit wise operation
2246 has only one use, that use is immediately following
2247 the defintion and the using iCode has only one
2248 operand or has two operands but one is literal &
2249 the result of that operation is not on stack then
2250 we can leave the result of this operation in acc:b
2252 if ((IS_ARITHMETIC_OP(ic)
2253 || IS_BITWISE_OP(ic)
2254 || ic->op == LEFT_OP || ic->op == RIGHT_OP
2255 || (ic->op == ADDRESS_OF && isOperandOnStack(IC_LEFT(ic)))
2257 IS_ITEMP(IC_RESULT(ic)) &&
2258 getSize(operandType(IC_RESULT(ic))) <= 2)
2260 packRegsForAccUse (ic);
2265 /*-----------------------------------------------------------------*/
2266 /* assignRegisters - assigns registers to each live range as need */
2267 /*-----------------------------------------------------------------*/
2268 void mcs51_assignRegisters (eBBlock **ebbs, int count)
2273 setToNull((void *)&_G.funcrUsed);
2274 mcs51_ptrRegReq = _G.stackExtend = _G.dataExtend = 0;
2275 /* if not register extentions then reduce number
2277 if (options.regExtend)
2282 /* change assignments this will remove some
2283 live ranges reducing some register pressure */
2284 for (i = 0 ; i < count ;i++ )
2285 packRegisters (ebbs[i]);
2287 if (options.dump_pack)
2288 dumpEbbsToFileExt(".dumppack",ebbs,count);
2290 /* first determine for each live range the number of
2291 registers & the type of registers required for each */
2294 /* and serially allocate registers */
2295 serialRegAssign(ebbs,count);
2297 /* if stack was extended then tell the user */
2298 if (_G.stackExtend) {
2299 /* werror(W_TOOMANY_SPILS,"stack", */
2300 /* _G.stackExtend,currFunc->name,""); */
2301 _G.stackExtend = 0 ;
2304 if (_G.dataExtend) {
2305 /* werror(W_TOOMANY_SPILS,"data space", */
2306 /* _G.dataExtend,currFunc->name,""); */
2310 /* after that create the register mask
2311 for each of the instruction */
2312 createRegMask (ebbs,count);
2314 /* redo that offsets for stacked automatic variables */
2315 redoStackOffsets ();
2317 if (options.dump_rassgn) {
2318 dumpEbbsToFileExt(".dumprassgn",ebbs,count);
2319 dumpLiveRanges(".lrange",liveRanges);
2322 /* do the overlaysegment stuff SDCCmem.c */
2323 doOverlays(ebbs,count);
2325 /* now get back the chain */
2326 ic = iCodeLabelOptimize(iCodeFromeBBlock (ebbs,count));
2331 /* free up any _G.stackSpil locations allocated */
2332 applyToSet(_G.stackSpil,deallocStackSpil);
2334 setToNull((void **)&_G.stackSpil);
2335 setToNull((void **)&_G.spiltSet);
2336 /* mark all registers as free */