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 -------------------------------------------------------------------------*/
29 /*-----------------------------------------------------------------*/
30 /* At this point we start getting processor specific although */
31 /* some routines are non-processor specific & can be reused when */
32 /* targetting other processors. The decision for this will have */
33 /* to be made on a routine by routine basis */
34 /* routines used to pack registers are most definitely not reusable*/
35 /* since the pack the registers depending strictly on the MCU */
36 /*-----------------------------------------------------------------*/
38 extern void gen51Code(iCode *);
47 bitVect *funcrUsed; /* registers used in a function */
52 /* Shared with gen.c */
53 int mcs51_ptrRegReq; /* one byte pointer register required */
59 { REG_GPR ,R2_IDX , REG_GPR , "r2", "ar2", "0", 2, 1 },
60 { REG_GPR ,R3_IDX , REG_GPR , "r3", "ar3", "0", 3, 1 },
61 { REG_GPR ,R4_IDX , REG_GPR , "r4", "ar4", "0", 4, 1 },
62 { REG_GPR ,R5_IDX , REG_GPR , "r5", "ar5", "0", 5, 1 },
63 { REG_GPR ,R6_IDX , REG_GPR , "r6", "ar6", "0", 6, 1 },
64 { REG_GPR ,R7_IDX , REG_GPR , "r7", "ar7", "0", 7, 1 },
65 { REG_PTR ,R0_IDX , REG_PTR , "r0" , "ar0", "0", 0, 1 },
66 { REG_PTR ,R1_IDX , REG_PTR , "r1" , "ar1", "0", 1, 1 },
67 { REG_GPR ,X8_IDX , REG_GPR , "x8", "x8" , "xreg", 0, 1 },
68 { REG_GPR ,X9_IDX , REG_GPR , "x9", "x9" , "xreg", 1, 1 },
69 { REG_GPR ,X10_IDX,REG_GPR , "x10", "x10", "xreg", 2, 1 },
70 { REG_GPR ,X11_IDX,REG_GPR , "x11", "x11", "xreg", 3, 1 },
71 { REG_GPR ,X12_IDX,REG_GPR , "x12", "x12", "xreg", 4, 1 },
72 { REG_CND ,CND_IDX,REG_CND , "C" , "C" , "xreg", 0, 1 },
75 static void spillThis (symbol *);
77 /*-----------------------------------------------------------------*/
78 /* allocReg - allocates register of given type */
79 /*-----------------------------------------------------------------*/
80 static regs *allocReg (short type)
84 for ( i = 0 ; i < mcs51_nRegs ; i++ ) {
86 /* if type is given as 0 then any
87 free register will do */
89 regs8051[i].isFree ) {
90 regs8051[i].isFree = 0;
93 bitVectSetBit(currFunc->regsUsed,i);
96 /* other wise look for specific type
98 if (regs8051[i].isFree &&
99 regs8051[i].type == type) {
100 regs8051[i].isFree = 0;
103 bitVectSetBit(currFunc->regsUsed,i);
110 /*-----------------------------------------------------------------*/
111 /* mcs51_regWithIdx - returns pointer to register wit index number */
112 /*-----------------------------------------------------------------*/
113 regs *mcs51_regWithIdx (int idx)
117 for (i=0;i < mcs51_nRegs;i++)
118 if (regs8051[i].rIdx == idx)
121 werror(E_INTERNAL_ERROR,__FILE__,__LINE__,
122 "regWithIdx not found");
126 /*-----------------------------------------------------------------*/
127 /* freeReg - frees a register */
128 /*-----------------------------------------------------------------*/
129 static void freeReg (regs *reg)
135 /*-----------------------------------------------------------------*/
136 /* nFreeRegs - returns number of free registers */
137 /*-----------------------------------------------------------------*/
138 static int nFreeRegs (int type)
143 for (i = 0 ; i < mcs51_nRegs; i++ )
144 if (regs8051[i].isFree && regs8051[i].type == type)
149 /*-----------------------------------------------------------------*/
150 /* nfreeRegsType - free registers with type */
151 /*-----------------------------------------------------------------*/
152 static int nfreeRegsType (int type)
155 if (type == REG_PTR) {
156 if ((nfr = nFreeRegs(type)) == 0)
157 return nFreeRegs(REG_GPR);
160 return nFreeRegs(type);
164 /*-----------------------------------------------------------------*/
165 /* allDefsOutOfRange - all definitions are out of a range */
166 /*-----------------------------------------------------------------*/
167 static bool allDefsOutOfRange (bitVect *defs,int fseq, int toseq)
174 for ( i = 0 ;i < defs->size ; i++ ) {
177 if (bitVectBitValue(defs,i) &&
178 (ic = hTabItemWithKey(iCodehTab,i)) &&
179 ( ic->seq >= fseq && ic->seq <= toseq))
188 /*-----------------------------------------------------------------*/
189 /* computeSpillable - given a point find the spillable live ranges */
190 /*-----------------------------------------------------------------*/
191 static bitVect *computeSpillable (iCode *ic)
195 /* spillable live ranges are those that are live at this
196 point . the following categories need to be subtracted
198 a) - those that are already spilt
199 b) - if being used by this one
200 c) - defined by this one */
202 spillable = bitVectCopy(ic->rlive);
204 bitVectCplAnd(spillable,_G.spiltSet); /* those already spilt */
206 bitVectCplAnd(spillable,ic->uses); /* used in this one */
207 bitVectUnSetBit(spillable,ic->defKey);
208 spillable = bitVectIntersect(spillable,_G.regAssigned);
213 /*-----------------------------------------------------------------*/
214 /* noSpilLoc - return true if a variable has no spil location */
215 /*-----------------------------------------------------------------*/
216 static int noSpilLoc (symbol *sym, eBBlock *ebp,iCode *ic)
218 return (sym->usl.spillLoc ? 0 : 1);
221 /*-----------------------------------------------------------------*/
222 /* hasSpilLoc - will return 1 if the symbol has spil location */
223 /*-----------------------------------------------------------------*/
224 static int hasSpilLoc (symbol *sym, eBBlock *ebp, iCode *ic)
226 return (sym->usl.spillLoc ? 1 : 0);
229 /*-----------------------------------------------------------------*/
230 /* directSpilLoc - will return 1 if the splilocation is in direct */
231 /*-----------------------------------------------------------------*/
232 static int directSpilLoc (symbol *sym, eBBlock *ebp, iCode *ic)
234 if ( sym->usl.spillLoc &&
235 (IN_DIRSPACE(SPEC_OCLS(sym->usl.spillLoc->etype))))
241 /*-----------------------------------------------------------------*/
242 /* hasSpilLocnoUptr - will return 1 if the symbol has spil location*/
243 /* but is not used as a pointer */
244 /*-----------------------------------------------------------------*/
245 static int hasSpilLocnoUptr (symbol *sym, eBBlock *ebp, iCode *ic)
247 return ((sym->usl.spillLoc && !sym->uptr) ? 1 : 0);
250 /*-----------------------------------------------------------------*/
251 /* rematable - will return 1 if the remat flag is set */
252 /*-----------------------------------------------------------------*/
253 static int rematable (symbol *sym, eBBlock *ebp, iCode *ic)
258 /*-----------------------------------------------------------------*/
259 /* notUsedInBlock - not used in this block */
260 /*-----------------------------------------------------------------*/
261 static int notUsedInBlock (symbol *sym, eBBlock *ebp, iCode *ic)
263 return (!bitVectBitsInCommon(sym->defs,ebp->usesDefs) &&
264 allDefsOutOfRange (sym->defs,ebp->fSeq,ebp->lSeq));
265 /* return (!bitVectBitsInCommon(sym->defs,ebp->usesDefs)); */
268 /*-----------------------------------------------------------------*/
269 /* notUsedInRemaining - not used or defined in remain of the block */
270 /*-----------------------------------------------------------------*/
271 static int notUsedInRemaining (symbol *sym, eBBlock *ebp, iCode *ic)
273 return ((usedInRemaining (operandFromSymbol(sym),ic) ? 0 : 1) &&
274 allDefsOutOfRange (sym->defs,ic->seq,ebp->lSeq));
277 /*-----------------------------------------------------------------*/
278 /* allLRs - return true for all */
279 /*-----------------------------------------------------------------*/
280 static int allLRs (symbol *sym, eBBlock *ebp, iCode *ic)
285 /*-----------------------------------------------------------------*/
286 /* liveRangesWith - applies function to a given set of live range */
287 /*-----------------------------------------------------------------*/
288 static set *liveRangesWith (bitVect *lrs, int (func)(symbol *,eBBlock *, iCode *),
289 eBBlock *ebp, iCode *ic)
294 if (!lrs || !lrs->size)
297 for ( i = 1 ; i < lrs->size ; i++ ) {
299 if (!bitVectBitValue(lrs,i))
302 /* if we don't find it in the live range
303 hash table we are in serious trouble */
304 if (!(sym = hTabItemWithKey(liveRanges,i))) {
305 werror(E_INTERNAL_ERROR,__FILE__,__LINE__,
306 "liveRangesWith could not find liveRange");
310 if (func(sym,ebp,ic) && bitVectBitValue(_G.regAssigned,sym->key))
311 addSetHead(&rset,sym);
318 /*-----------------------------------------------------------------*/
319 /* leastUsedLR - given a set determines which is the least used */
320 /*-----------------------------------------------------------------*/
321 static symbol *leastUsedLR (set *sset)
323 symbol *sym = NULL, *lsym = NULL ;
325 sym = lsym = setFirstItem(sset);
330 for (; lsym; lsym = setNextItem(sset)) {
332 /* if usage is the same then prefer
333 the spill the smaller of the two */
334 if ( lsym->used == sym->used )
335 if (getSize(lsym->type) < getSize(sym->type))
339 if (lsym->used < sym->used )
344 setToNull((void **)&sset);
349 /*-----------------------------------------------------------------*/
350 /* noOverLap - will iterate through the list looking for over lap */
351 /*-----------------------------------------------------------------*/
352 static int noOverLap (set *itmpStack, symbol *fsym)
357 for (sym = setFirstItem(itmpStack); sym;
358 sym = setNextItem(itmpStack)) {
359 if (sym->liveTo > fsym->liveFrom )
367 /*-----------------------------------------------------------------*/
368 /* isFree - will return 1 if the a free spil location is found */
369 /*-----------------------------------------------------------------*/
370 static DEFSETFUNC(isFree)
373 V_ARG(symbol **,sloc);
374 V_ARG(symbol *,fsym);
376 /* if already found */
380 /* if it is free && and the itmp assigned to
381 this does not have any overlapping live ranges
382 with the one currently being assigned and
383 the size can be accomodated */
385 noOverLap(sym->usl.itmpStack,fsym) &&
386 getSize(sym->type) >= getSize(fsym->type)) {
394 /*-----------------------------------------------------------------*/
395 /* spillLRWithPtrReg :- will spil those live ranges which use PTR */
396 /*-----------------------------------------------------------------*/
397 static void spillLRWithPtrReg (symbol *forSym)
403 if (!_G.regAssigned ||
404 bitVectIsZero(_G.regAssigned))
407 r0 = mcs51_regWithIdx(R0_IDX);
408 r1 = mcs51_regWithIdx(R1_IDX);
410 /* for all live ranges */
411 for (lrsym = hTabFirstItem(liveRanges,&k) ; lrsym ;
412 lrsym = hTabNextItem(liveRanges,&k) ) {
415 /* if no registers assigned to it or
417 /* if it does not overlap with this then
418 not need to spill it */
420 if (lrsym->isspilt || !lrsym->nRegs ||
421 (lrsym->liveTo < forSym->liveFrom))
424 /* go thru the registers : if it is either
425 r0 or r1 then spil it */
426 for (j = 0 ; j < lrsym->nRegs ; j++ )
427 if (lrsym->regs[j] == r0 ||
428 lrsym->regs[j] == r1 ) {
436 /*-----------------------------------------------------------------*/
437 /* createStackSpil - create a location on the stack to spil */
438 /*-----------------------------------------------------------------*/
439 static symbol *createStackSpil (symbol *sym)
442 int useXstack, model, noOverlay;
445 /* first go try and find a free one that is already
446 existing on the stack */
447 if (applyToSet(_G.stackSpil,isFree,&sloc, sym)) {
448 /* found a free one : just update & return */
449 sym->usl.spillLoc = sloc;
452 addSetHead(&sloc->usl.itmpStack,sym);
456 /* could not then have to create one , this is the hard part
457 we need to allocate this on the stack : this is really a
458 hack!! but cannot think of anything better at this time */
460 sprintf(buffer,"sloc%d",_G.slocNum++);
461 sloc = newiTemp(buffer);
463 /* set the type to the spilling symbol */
464 sloc->type = copyLinkChain(sym->type);
465 sloc->etype = getSpec(sloc->type);
466 SPEC_SCLS(sloc->etype) = S_AUTO ;
467 SPEC_EXTR(sloc->etype) = 0;
469 /* we don't allow it to be allocated`
470 onto the external stack since : so we
471 temporarily turn it off ; we also
472 turn off memory model to prevent
473 the spil from going to the external storage
474 and turn off overlaying
477 useXstack = options.useXstack;
478 model = options.model;
479 noOverlay = options.noOverlay;
480 stackAuto = options.stackAuto;
481 options.noOverlay = 1;
482 options.model = options.useXstack = 0;
486 options.useXstack = useXstack;
487 options.model = model;
488 options.noOverlay = noOverlay;
489 options.stackAuto = stackAuto;
490 sloc->isref = 1; /* to prevent compiler warning */
492 /* if it is on the stack then update the stack */
493 if (IN_STACK(sloc->etype)) {
494 currFunc->stack += getSize(sloc->type);
495 _G.stackExtend += getSize(sloc->type);
497 _G.dataExtend += getSize(sloc->type);
499 /* add it to the _G.stackSpil set */
500 addSetHead(&_G.stackSpil,sloc);
501 sym->usl.spillLoc = sloc;
504 /* add it to the set of itempStack set
505 of the spill location */
506 addSetHead(&sloc->usl.itmpStack,sym);
510 /*-----------------------------------------------------------------*/
511 /* isSpiltOnStack - returns true if the spil location is on stack */
512 /*-----------------------------------------------------------------*/
513 static bool isSpiltOnStack (symbol *sym)
523 /* if (sym->_G.stackSpil) */
526 if (!sym->usl.spillLoc)
529 etype = getSpec(sym->usl.spillLoc->type);
536 /*-----------------------------------------------------------------*/
537 /* spillThis - spils a specific operand */
538 /*-----------------------------------------------------------------*/
539 static void spillThis (symbol *sym)
542 /* if this is rematerializable or has a spillLocation
543 we are okay, else we need to create a spillLocation
545 if (!(sym->remat || sym->usl.spillLoc))
546 createStackSpil (sym);
549 /* mark it has spilt & put it in the spilt set */
551 _G.spiltSet = bitVectSetBit(_G.spiltSet,sym->key);
553 bitVectUnSetBit(_G.regAssigned,sym->key);
555 for (i = 0 ; i < sym->nRegs ; i++)
558 freeReg(sym->regs[i]);
562 /* if spilt on stack then free up r0 & r1
563 if they could have been assigned to some
565 if (!mcs51_ptrRegReq && isSpiltOnStack(sym)) {
567 spillLRWithPtrReg(sym);
570 if (sym->usl.spillLoc && !sym->remat)
571 sym->usl.spillLoc->allocreq = 1;
575 /*-----------------------------------------------------------------*/
576 /* selectSpil - select a iTemp to spil : rather a simple procedure */
577 /*-----------------------------------------------------------------*/
578 static symbol *selectSpil (iCode *ic, eBBlock *ebp, symbol *forSym)
580 bitVect *lrcs= NULL ;
584 /* get the spillable live ranges */
585 lrcs = computeSpillable (ic);
587 /* get all live ranges that are rematerizable */
588 if ((selectS = liveRangesWith(lrcs,rematable,ebp,ic))) {
590 /* return the least used of these */
591 return leastUsedLR(selectS);
594 /* get live ranges with spillLocations in direct space */
595 if ((selectS = liveRangesWith(lrcs,directSpilLoc,ebp,ic))) {
596 sym = leastUsedLR(selectS);
597 strcpy(sym->rname,(sym->usl.spillLoc->rname[0] ?
598 sym->usl.spillLoc->rname :
599 sym->usl.spillLoc->name));
601 /* mark it as allocation required */
602 sym->usl.spillLoc->allocreq = 1;
606 /* if the symbol is local to the block then */
607 if (forSym->liveTo < ebp->lSeq ) {
609 /* check if there are any live ranges allocated
610 to registers that are not used in this block */
611 if (!_G.blockSpil && (selectS = liveRangesWith(lrcs,notUsedInBlock,ebp,ic))) {
612 sym = leastUsedLR(selectS);
613 /* if this is not rematerializable */
621 /* check if there are any live ranges that not
622 used in the remainder of the block */
623 if (!_G.blockSpil && (selectS = liveRangesWith(lrcs,notUsedInRemaining,ebp,ic))) {
624 sym = leastUsedLR (selectS);
633 /* find live ranges with spillocation && not used as pointers */
634 if ((selectS = liveRangesWith(lrcs,hasSpilLocnoUptr,ebp,ic))) {
636 sym = leastUsedLR(selectS);
637 /* mark this as allocation required */
638 sym->usl.spillLoc->allocreq = 1;
642 /* find live ranges with spillocation */
643 if ((selectS = liveRangesWith(lrcs,hasSpilLoc,ebp,ic))) {
645 sym = leastUsedLR(selectS);
646 sym->usl.spillLoc->allocreq = 1;
650 /* couldn't find then we need to create a spil
651 location on the stack , for which one? the least
653 if ((selectS = liveRangesWith(lrcs,noSpilLoc,ebp,ic))) {
655 /* return a created spil location */
656 sym = createStackSpil(leastUsedLR(selectS));
657 sym->usl.spillLoc->allocreq = 1;
661 /* this is an extreme situation we will spill
662 this one : happens very rarely but it does happen */
663 spillThis ( forSym );
668 /*-----------------------------------------------------------------*/
669 /* spilSomething - spil some variable & mark registers as free */
670 /*-----------------------------------------------------------------*/
671 static bool spilSomething (iCode *ic, eBBlock *ebp, symbol *forSym)
676 /* get something we can spil */
677 ssym = selectSpil(ic,ebp,forSym);
679 /* mark it as spilt */
681 _G.spiltSet = bitVectSetBit(_G.spiltSet,ssym->key);
683 /* mark it as not register assigned &
684 take it away from the set */
685 bitVectUnSetBit(_G.regAssigned,ssym->key);
687 /* mark the registers as free */
688 for (i = 0 ; i < ssym->nRegs ;i++ )
690 freeReg(ssym->regs[i]);
692 /* if spilt on stack then free up r0 & r1
693 if they could have been assigned to as gprs */
694 if (!mcs51_ptrRegReq && isSpiltOnStack(ssym) ) {
696 spillLRWithPtrReg(ssym);
699 /* if this was a block level spil then insert push & pop
700 at the start & end of block respectively */
701 if (ssym->blockSpil) {
702 iCode *nic = newiCode(IPUSH,operandFromSymbol(ssym),NULL);
703 /* add push to the start of the block */
704 addiCodeToeBBlock(ebp,nic,( ebp->sch->op == LABEL ?
705 ebp->sch->next : ebp->sch));
706 nic = newiCode(IPOP,operandFromSymbol(ssym),NULL);
707 /* add pop to the end of the block */
708 addiCodeToeBBlock(ebp,nic,NULL);
711 /* if spilt because not used in the remainder of the
712 block then add a push before this instruction and
713 a pop at the end of the block */
714 if (ssym->remainSpil) {
716 iCode *nic = newiCode(IPUSH,operandFromSymbol(ssym),NULL);
717 /* add push just before this instruction */
718 addiCodeToeBBlock(ebp,nic,ic);
720 nic = newiCode(IPOP,operandFromSymbol(ssym),NULL);
721 /* add pop to the end of the block */
722 addiCodeToeBBlock(ebp,nic,NULL);
731 /*-----------------------------------------------------------------*/
732 /* getRegPtr - will try for PTR if not a GPR type if not spil */
733 /*-----------------------------------------------------------------*/
734 regs *getRegPtr (iCode *ic, eBBlock *ebp, symbol *sym)
739 /* try for a ptr type */
740 if ((reg = allocReg(REG_PTR)))
743 /* try for gpr type */
744 if ((reg = allocReg(REG_GPR)))
747 /* we have to spil */
748 if (!spilSomething (ic,ebp,sym))
751 /* this looks like an infinite loop but
752 in really selectSpil will abort */
756 /*-----------------------------------------------------------------*/
757 /* getRegGpr - will try for GPR if not spil */
758 /*-----------------------------------------------------------------*/
759 static regs *getRegGpr (iCode *ic, eBBlock *ebp,symbol *sym)
764 /* try for gpr type */
765 if ((reg = allocReg(REG_GPR)))
768 if (!mcs51_ptrRegReq)
769 if ((reg = allocReg(REG_PTR)))
772 /* we have to spil */
773 if (!spilSomething (ic,ebp,sym))
776 /* this looks like an infinite loop but
777 in really selectSpil will abort */
781 /*-----------------------------------------------------------------*/
782 /* symHasReg - symbol has a given register */
783 /*-----------------------------------------------------------------*/
784 static bool symHasReg(symbol *sym,regs *reg)
788 for ( i = 0 ; i < sym->nRegs ; i++)
789 if (sym->regs[i] == reg)
795 /*-----------------------------------------------------------------*/
796 /* deassignLRs - check the live to and if they have registers & are*/
797 /* not spilt then free up the registers */
798 /*-----------------------------------------------------------------*/
799 static void deassignLRs (iCode *ic, eBBlock *ebp)
805 for (sym = hTabFirstItem(liveRanges,&k); sym;
806 sym = hTabNextItem(liveRanges,&k)) {
809 /* if it does not end here */
810 if (sym->liveTo > ic->seq )
813 /* if it was spilt on stack then we can
814 mark the stack spil location as free */
816 if (sym->stackSpil) {
817 sym->usl.spillLoc->isFree = 1;
823 if (!bitVectBitValue(_G.regAssigned,sym->key))
826 /* special case check if this is an IFX &
827 the privious one was a pop and the
828 previous one was not spilt then keep track
830 if (ic->op == IFX && ic->prev &&
831 ic->prev->op == IPOP &&
832 !ic->prev->parmPush &&
833 !OP_SYMBOL(IC_LEFT(ic->prev))->isspilt)
834 psym = OP_SYMBOL(IC_LEFT(ic->prev));
839 bitVectUnSetBit(_G.regAssigned,sym->key);
841 /* if the result of this one needs registers
842 and does not have it then assign it right
845 ! (SKIP_IC2(ic) || /* not a special icode */
846 ic->op == JUMPTABLE ||
852 (result = OP_SYMBOL(IC_RESULT(ic))) && /* has a result */
853 result->liveTo > ic->seq && /* and will live beyond this */
854 result->liveTo <= ebp->lSeq && /* does not go beyond this block */
855 result->regType == sym->regType && /* same register types */
856 result->nRegs && /* which needs registers */
857 ! result->isspilt && /* and does not already have them */
859 ! bitVectBitValue(_G.regAssigned,result->key) &&
860 /* the number of free regs + number of regs in this LR
861 can accomodate the what result Needs */
862 ((nfreeRegsType(result->regType) +
863 sym->nRegs) >= result->nRegs)
866 for (i = 0 ; i < max(sym->nRegs,result->nRegs) ; i++)
868 result->regs[i] = sym->regs[i] ;
870 result->regs[i] = getRegGpr (ic,ebp,result);
872 _G.regAssigned = bitVectSetBit(_G.regAssigned,result->key);
876 /* free the remaining */
877 for (; i < sym->nRegs ; i++) {
879 if (!symHasReg(psym,sym->regs[i]))
880 freeReg(sym->regs[i]);
882 freeReg(sym->regs[i]);
889 /*-----------------------------------------------------------------*/
890 /* reassignLR - reassign this to registers */
891 /*-----------------------------------------------------------------*/
892 static void reassignLR (operand *op)
894 symbol *sym = OP_SYMBOL(op);
897 /* not spilt any more */
898 sym->isspilt = sym->blockSpil = sym->remainSpil = 0;
899 bitVectUnSetBit(_G.spiltSet,sym->key);
901 _G.regAssigned = bitVectSetBit(_G.regAssigned,sym->key);
905 for (i=0;i<sym->nRegs;i++)
906 sym->regs[i]->isFree = 0;
909 /*-----------------------------------------------------------------*/
910 /* willCauseSpill - determines if allocating will cause a spill */
911 /*-----------------------------------------------------------------*/
912 static int willCauseSpill ( int nr, int rt)
914 /* first check if there are any avlb registers
915 of te type required */
917 /* special case for pointer type
918 if pointer type not avlb then
919 check for type gpr */
920 if (nFreeRegs(rt) >= nr)
922 if (nFreeRegs(REG_GPR) >= nr)
925 if (mcs51_ptrRegReq) {
926 if (nFreeRegs(rt) >= nr)
929 if (nFreeRegs(REG_PTR) +
930 nFreeRegs(REG_GPR) >= nr)
935 /* it will cause a spil */
939 /*-----------------------------------------------------------------*/
940 /* positionRegs - the allocator can allocate same registers to res-*/
941 /* ult and operand, if this happens make sure they are in the same */
942 /* position as the operand otherwise chaos results */
943 /*-----------------------------------------------------------------*/
944 static void positionRegs (symbol *result, symbol *opsym, int lineno)
946 int count = min(result->nRegs,opsym->nRegs);
947 int i , j = 0, shared = 0;
949 /* if the result has been spilt then cannot share */
954 /* first make sure that they actually share */
955 for ( i = 0 ; i < count; i++ ) {
956 for (j = 0 ; j < count ; j++ ) {
957 if (result->regs[i] == opsym->regs[j] && i !=j) {
965 regs *tmp = result->regs[i];
966 result->regs[i] = result->regs[j];
967 result->regs[j] = tmp;
972 /*-----------------------------------------------------------------*/
973 /* serialRegAssign - serially allocate registers to the variables */
974 /*-----------------------------------------------------------------*/
975 static void serialRegAssign (eBBlock **ebbs, int count)
980 for (i = 0; i < count ; i++ ) {
984 if (ebbs[i]->noPath &&
985 (ebbs[i]->entryLabel != entryLabel &&
986 ebbs[i]->entryLabel != returnLabel ))
989 /* of all instructions do */
990 for (ic = ebbs[i]->sch ; ic ; ic = ic->next) {
992 /* if this is an ipop that means some live
993 range will have to be assigned again */
995 reassignLR (IC_LEFT(ic));
997 /* if result is present && is a true symbol */
998 if (IC_RESULT(ic) && ic->op != IFX &&
999 IS_TRUE_SYMOP(IC_RESULT(ic)))
1000 OP_SYMBOL(IC_RESULT(ic))->allocreq = 1;
1002 /* take away registers from live
1003 ranges that end at this instruction */
1004 deassignLRs (ic, ebbs[i]) ;
1006 /* some don't need registers */
1008 ic->op == JUMPTABLE ||
1012 (IC_RESULT(ic) &&POINTER_SET(ic)) )
1015 /* now we need to allocate registers
1016 only for the result */
1017 if (IC_RESULT(ic)) {
1018 symbol *sym = OP_SYMBOL(IC_RESULT(ic));
1024 /* if it does not need or is spilt
1025 or is already assigned to registers
1026 or will not live beyond this instructions */
1029 bitVectBitValue(_G.regAssigned,sym->key) ||
1030 sym->liveTo <= ic->seq)
1033 /* if some liverange has been spilt at the block level
1034 and this one live beyond this block then spil this
1036 if (_G.blockSpil && sym->liveTo > ebbs[i]->lSeq) {
1040 /* if trying to allocate this will cause
1041 a spill and there is nothing to spill
1042 or this one is rematerializable then
1044 willCS = willCauseSpill(sym->nRegs,sym->regType);
1045 spillable = computeSpillable(ic);
1047 (willCS && bitVectIsZero(spillable) ) ) {
1054 /* if it has a spillocation & is used less than
1055 all other live ranges then spill this */
1056 if ( willCS && sym->usl.spillLoc ) {
1059 leastUsedLR(liveRangesWith (spillable ,
1064 leastUsed->used > sym->used) {
1070 /* if we need ptr regs for the right side
1072 if (POINTER_GET(ic) && getSize(OP_SYMBOL(IC_LEFT(ic))->type) < 2) {
1076 /* else we assign registers to it */
1077 _G.regAssigned = bitVectSetBit(_G.regAssigned,sym->key);
1079 for (j = 0 ; j < sym->nRegs ;j++ ) {
1080 if (sym->regType == REG_PTR)
1081 sym->regs[j] = getRegPtr(ic,ebbs[i],sym);
1083 sym->regs[j] = getRegGpr(ic,ebbs[i],sym);
1085 /* if the allocation falied which means
1086 this was spilt then break */
1090 /* if it shares registers with operands make sure
1091 that they are in the same position */
1092 if (IC_LEFT(ic) && IS_SYMOP(IC_LEFT(ic)) &&
1093 OP_SYMBOL(IC_LEFT(ic))->nRegs && ic->op != '=')
1094 positionRegs(OP_SYMBOL(IC_RESULT(ic)),
1095 OP_SYMBOL(IC_LEFT(ic)),ic->lineno);
1096 /* do the same for the right operand */
1097 if (IC_RIGHT(ic) && IS_SYMOP(IC_RIGHT(ic)) &&
1098 OP_SYMBOL(IC_RIGHT(ic))->nRegs && ic->op != '=')
1099 positionRegs(OP_SYMBOL(IC_RESULT(ic)),
1100 OP_SYMBOL(IC_RIGHT(ic)),ic->lineno);
1112 /*-----------------------------------------------------------------*/
1113 /* rUmaskForOp :- returns register mask for an operand */
1114 /*-----------------------------------------------------------------*/
1115 static bitVect *rUmaskForOp (operand *op)
1121 /* only temporaries are assigned registers */
1125 sym = OP_SYMBOL(op);
1127 /* if spilt or no registers assigned to it
1129 if (sym->isspilt || !sym->nRegs)
1132 rumask = newBitVect(mcs51_nRegs);
1134 for (j = 0; j < sym->nRegs; j++) {
1135 rumask = bitVectSetBit(rumask,
1136 sym->regs[j]->rIdx);
1142 /*-----------------------------------------------------------------*/
1143 /* regsUsedIniCode :- returns bit vector of registers used in iCode*/
1144 /*-----------------------------------------------------------------*/
1145 static bitVect *regsUsedIniCode (iCode *ic)
1147 bitVect *rmask = newBitVect(mcs51_nRegs);
1149 /* do the special cases first */
1150 if (ic->op == IFX ) {
1151 rmask = bitVectUnion(rmask,
1152 rUmaskForOp(IC_COND(ic)));
1156 /* for the jumptable */
1157 if (ic->op == JUMPTABLE) {
1158 rmask = bitVectUnion(rmask,
1159 rUmaskForOp(IC_JTCOND(ic)));
1164 /* of all other cases */
1166 rmask = bitVectUnion(rmask,
1167 rUmaskForOp(IC_LEFT(ic)));
1171 rmask = bitVectUnion(rmask,
1172 rUmaskForOp(IC_RIGHT(ic)));
1175 rmask = bitVectUnion(rmask,
1176 rUmaskForOp(IC_RESULT(ic)));
1182 /*-----------------------------------------------------------------*/
1183 /* createRegMask - for each instruction will determine the regsUsed*/
1184 /*-----------------------------------------------------------------*/
1185 static void createRegMask (eBBlock **ebbs, int count)
1189 /* for all blocks */
1190 for (i = 0; i < count ; i++ ) {
1193 if ( ebbs[i]->noPath &&
1194 ( ebbs[i]->entryLabel != entryLabel &&
1195 ebbs[i]->entryLabel != returnLabel ))
1198 /* for all instructions */
1199 for ( ic = ebbs[i]->sch ; ic ; ic = ic->next ) {
1203 if (SKIP_IC2(ic) || !ic->rlive)
1206 /* first mark the registers used in this
1208 ic->rUsed = regsUsedIniCode(ic);
1209 _G.funcrUsed = bitVectUnion(_G.funcrUsed,ic->rUsed);
1211 /* now create the register mask for those
1212 registers that are in use : this is a
1213 super set of ic->rUsed */
1214 ic->rMask = newBitVect(mcs51_nRegs+1);
1216 /* for all live Ranges alive at this point */
1217 for (j = 1; j < ic->rlive->size; j++ ) {
1221 /* if not alive then continue */
1222 if (!bitVectBitValue(ic->rlive,j))
1225 /* find the live range we are interested in */
1226 if (!(sym = hTabItemWithKey(liveRanges,j))) {
1227 werror (E_INTERNAL_ERROR,__FILE__,__LINE__,
1228 "createRegMask cannot find live range");
1232 /* if no register assigned to it */
1233 if (!sym->nRegs || sym->isspilt)
1236 /* for all the registers allocated to it */
1237 for (k = 0 ; k < sym->nRegs ;k++)
1240 bitVectSetBit(ic->rMask,sym->regs[k]->rIdx);
1246 /*-----------------------------------------------------------------*/
1247 /* rematStr - returns the rematerialized string for a remat var */
1248 /*-----------------------------------------------------------------*/
1249 static char *rematStr (symbol *sym)
1252 iCode *ic = sym->rematiCode;
1256 /* if plus or minus print the right hand side */
1257 if (ic->op == '+' || ic->op == '-') {
1258 sprintf(s,"0x%04x %c ",(int) operandLitValue(IC_RIGHT(ic)),
1261 ic = OP_SYMBOL(IC_LEFT(ic))->rematiCode;
1265 /* we reached the end */
1266 sprintf(s,"%s",OP_SYMBOL(IC_LEFT(ic))->rname);
1273 /*-----------------------------------------------------------------*/
1274 /* regTypeNum - computes the type & number of registers required */
1275 /*-----------------------------------------------------------------*/
1276 static void regTypeNum ()
1282 /* for each live range do */
1283 for ( sym = hTabFirstItem(liveRanges,&k); sym ;
1284 sym = hTabNextItem(liveRanges,&k)) {
1286 /* if used zero times then no registers needed */
1287 if ((sym->liveTo - sym->liveFrom) == 0)
1291 /* if the live range is a temporary */
1294 /* if the type is marked as a conditional */
1295 if (sym->regType == REG_CND)
1298 /* if used in return only then we don't
1300 if (sym->ruonly || sym->accuse) {
1301 if (IS_AGGREGATE(sym->type) || sym->isptr)
1302 sym->type = aggrToPtr(sym->type,FALSE);
1306 /* if the symbol has only one definition &
1307 that definition is a get_pointer and the
1308 pointer we are getting is rematerializable and
1311 if (bitVectnBitsOn(sym->defs) == 1 &&
1312 (ic = hTabItemWithKey(iCodehTab,
1313 bitVectFirstBit(sym->defs))) &&
1315 !IS_BITVAR(sym->etype)) {
1318 /* if remat in data space */
1319 if (OP_SYMBOL(IC_LEFT(ic))->remat &&
1320 DCL_TYPE(aggrToPtr(sym->type,FALSE)) == POINTER) {
1322 /* create a psuedo symbol & force a spil */
1323 symbol *psym = newSymbol(rematStr(OP_SYMBOL(IC_LEFT(ic))),1);
1324 psym->type = sym->type;
1325 psym->etype = sym->etype;
1326 strcpy(psym->rname,psym->name);
1328 sym->usl.spillLoc = psym;
1332 /* if in data space or idata space then try to
1333 allocate pointer register */
1337 /* if not then we require registers */
1338 sym->nRegs = ((IS_AGGREGATE(sym->type) || sym->isptr ) ?
1339 getSize(sym->type = aggrToPtr(sym->type,FALSE)) :
1340 getSize(sym->type));
1342 if (sym->nRegs > 4) {
1343 fprintf(stderr,"allocated more than 4 or 0 registers for type ");
1344 printTypeChain(sym->type,stderr);fprintf(stderr,"\n");
1347 /* determine the type of register required */
1348 if (sym->nRegs == 1 &&
1349 IS_PTR(sym->type) &&
1351 sym->regType = REG_PTR ;
1353 sym->regType = REG_GPR ;
1356 /* for the first run we don't provide */
1357 /* registers for true symbols we will */
1358 /* see how things go */
1364 /*-----------------------------------------------------------------*/
1365 /* freeAllRegs - mark all registers as free */
1366 /*-----------------------------------------------------------------*/
1367 static void freeAllRegs()
1371 for (i=0;i< mcs51_nRegs;i++ )
1372 regs8051[i].isFree = 1;
1375 /*-----------------------------------------------------------------*/
1376 /* deallocStackSpil - this will set the stack pointer back */
1377 /*-----------------------------------------------------------------*/
1378 static DEFSETFUNC(deallocStackSpil)
1386 /*-----------------------------------------------------------------*/
1387 /* farSpacePackable - returns the packable icode for far variables */
1388 /*-----------------------------------------------------------------*/
1389 static iCode *farSpacePackable (iCode *ic)
1393 /* go thru till we find a definition for the
1394 symbol on the right */
1395 for ( dic = ic->prev ; dic ; dic = dic->prev) {
1397 /* if the definition is a call then no */
1398 if ((dic->op == CALL || dic->op == PCALL) &&
1399 IC_RESULT(dic)->key == IC_RIGHT(ic)->key) {
1403 /* if shift by unknown amount then not */
1404 if ((dic->op == LEFT_OP || dic->op == RIGHT_OP) &&
1405 IC_RESULT(dic)->key == IC_RIGHT(ic)->key)
1408 /* if pointer get and size > 1 */
1409 if (POINTER_GET(dic) &&
1410 getSize(aggrToPtr(operandType(IC_LEFT(dic)),FALSE)) > 1)
1413 if (POINTER_SET(dic) &&
1414 getSize(aggrToPtr(operandType(IC_RESULT(dic)),FALSE)) > 1)
1417 /* if any three is a true symbol in far space */
1418 if (IC_RESULT(dic) &&
1419 IS_TRUE_SYMOP(IC_RESULT(dic)) &&
1420 isOperandInFarSpace(IC_RESULT(dic)))
1423 if (IC_RIGHT(dic) &&
1424 IS_TRUE_SYMOP(IC_RIGHT(dic)) &&
1425 isOperandInFarSpace(IC_RIGHT(dic)) &&
1426 !isOperandEqual(IC_RIGHT(dic),IC_RESULT(ic)))
1430 IS_TRUE_SYMOP(IC_LEFT(dic)) &&
1431 isOperandInFarSpace(IC_LEFT(dic)) &&
1432 !isOperandEqual(IC_LEFT(dic),IC_RESULT(ic)))
1435 if (isOperandEqual(IC_RIGHT(ic),IC_RESULT(dic))) {
1436 if ( (dic->op == LEFT_OP ||
1437 dic->op == RIGHT_OP ||
1439 IS_OP_LITERAL(IC_RIGHT(dic)))
1449 /*-----------------------------------------------------------------*/
1450 /* packRegsForAssign - register reduction for assignment */
1451 /*-----------------------------------------------------------------*/
1452 static int packRegsForAssign (iCode *ic,eBBlock *ebp)
1457 /* !IS_TRUE_SYMOP(IC_RESULT(ic)) || */
1458 !IS_ITEMP(IC_RIGHT(ic)) ||
1459 OP_LIVETO(IC_RIGHT(ic)) > ic->seq ||
1460 OP_SYMBOL(IC_RIGHT(ic))->isind)
1463 /* if the true symbol is defined in far space or on stack
1464 then we should not since this will increase register pressure */
1465 if (isOperandInFarSpace(IC_RESULT(ic))) {
1466 if ((dic = farSpacePackable(ic)))
1472 /* find the definition of iTempNN scanning backwards if we find a
1473 a use of the true symbol in before we find the definition then
1475 for ( dic = ic->prev ; dic ; dic = dic->prev) {
1477 /* if there is a function call and this is
1478 a parameter & not my parameter then don't pack it */
1479 if ( (dic->op == CALL || dic->op == PCALL) &&
1480 (OP_SYMBOL(IC_RESULT(ic))->_isparm &&
1481 !OP_SYMBOL(IC_RESULT(ic))->ismyparm)) {
1489 if (IS_SYMOP(IC_RESULT(dic)) &&
1490 IC_RESULT(dic)->key == IC_RIGHT(ic)->key) {
1491 if (POINTER_SET(dic))
1497 if (IS_SYMOP(IC_RIGHT(dic)) &&
1498 (IC_RIGHT(dic)->key == IC_RESULT(ic)->key ||
1499 IC_RIGHT(dic)->key == IC_RIGHT(ic)->key)) {
1504 if (IS_SYMOP(IC_LEFT(dic)) &&
1505 (IC_LEFT(dic)->key == IC_RESULT(ic)->key ||
1506 IC_LEFT(dic)->key == IC_RIGHT(ic)->key)) {
1511 if (POINTER_SET(dic) &&
1512 IC_RESULT(dic)->key == IC_RESULT(ic)->key ) {
1519 return 0 ; /* did not find */
1521 /* if the result is on stack or iaccess then it must be
1522 the same atleast one of the operands */
1523 if (OP_SYMBOL(IC_RESULT(ic))->onStack ||
1524 OP_SYMBOL(IC_RESULT(ic))->iaccess ) {
1526 /* the operation has only one symbol
1527 operator then we can pack */
1528 if ((IC_LEFT(dic) && !IS_SYMOP(IC_LEFT(dic))) ||
1529 (IC_RIGHT(dic) && !IS_SYMOP(IC_RIGHT(dic))))
1532 if (!((IC_LEFT(dic) &&
1533 IC_RESULT(ic)->key == IC_LEFT(dic)->key) ||
1535 IC_RESULT(ic)->key == IC_RIGHT(dic)->key)))
1539 /* found the definition */
1540 /* replace the result with the result of */
1541 /* this assignment and remove this assignment */
1542 IC_RESULT(dic) = IC_RESULT(ic) ;
1544 if (IS_ITEMP(IC_RESULT(dic)) && OP_SYMBOL(IC_RESULT(dic))->liveFrom > dic->seq) {
1545 OP_SYMBOL(IC_RESULT(dic))->liveFrom = dic->seq;
1547 /* delete from liverange table also
1548 delete from all the points inbetween and the new
1550 for ( sic = dic; sic != ic ; sic = sic->next ) {
1551 bitVectUnSetBit(sic->rlive,IC_RESULT(ic)->key);
1552 if (IS_ITEMP(IC_RESULT(dic)))
1553 bitVectSetBit(sic->rlive,IC_RESULT(dic)->key);
1556 remiCodeFromeBBlock(ebp,ic);
1561 /*-----------------------------------------------------------------*/
1562 /* findAssignToSym : scanning backwards looks for first assig found*/
1563 /*-----------------------------------------------------------------*/
1564 static iCode *findAssignToSym (operand *op,iCode *ic)
1568 for (dic = ic->prev ; dic ; dic = dic->prev) {
1570 /* if definition by assignment */
1571 if (dic->op == '=' &&
1572 !POINTER_SET(dic) &&
1573 IC_RESULT(dic)->key == op->key
1574 /* && IS_TRUE_SYMOP(IC_RIGHT(dic)) */
1577 /* we are interested only if defined in far space */
1578 /* or in stack space in case of + & - */
1580 /* if assigned to a non-symbol then return
1582 if (!IS_SYMOP(IC_RIGHT(dic)))
1585 /* if the symbol is in far space then
1587 if (isOperandInFarSpace(IC_RIGHT(dic)))
1590 /* for + & - operations make sure that
1591 if it is on the stack it is the same
1592 as one of the three operands */
1593 if ((ic->op == '+' || ic->op == '-') &&
1594 OP_SYMBOL(IC_RIGHT(dic))->onStack) {
1596 if ( IC_RESULT(ic)->key != IC_RIGHT(dic)->key &&
1597 IC_LEFT(ic)->key != IC_RIGHT(dic)->key &&
1598 IC_RIGHT(ic)->key != IC_RIGHT(dic)->key)
1606 /* if we find an usage then we cannot delete it */
1607 if (IC_LEFT(dic) && IC_LEFT(dic)->key == op->key)
1610 if (IC_RIGHT(dic) && IC_RIGHT(dic)->key == op->key)
1613 if (POINTER_SET(dic) && IC_RESULT(dic)->key == op->key)
1617 /* now make sure that the right side of dic
1618 is not defined between ic & dic */
1620 iCode *sic = dic->next ;
1622 for (; sic != ic ; sic = sic->next)
1623 if (IC_RESULT(sic) &&
1624 IC_RESULT(sic)->key == IC_RIGHT(dic)->key)
1633 /*-----------------------------------------------------------------*/
1634 /* packRegsForSupport :- reduce some registers for support calls */
1635 /*-----------------------------------------------------------------*/
1636 static int packRegsForSupport (iCode *ic, eBBlock *ebp)
1639 /* for the left & right operand :- look to see if the
1640 left was assigned a true symbol in far space in that
1641 case replace them */
1642 if (IS_ITEMP(IC_LEFT(ic)) &&
1643 OP_SYMBOL(IC_LEFT(ic))->liveTo <= ic->seq) {
1644 iCode *dic = findAssignToSym(IC_LEFT(ic),ic);
1650 /* found it we need to remove it from the
1652 for ( sic = dic; sic != ic ; sic = sic->next )
1653 bitVectUnSetBit(sic->rlive,IC_LEFT(ic)->key);
1655 IC_LEFT(ic)->operand.symOperand =
1656 IC_RIGHT(dic)->operand.symOperand;
1657 IC_LEFT(ic)->key = IC_RIGHT(dic)->operand.symOperand->key;
1658 remiCodeFromeBBlock(ebp,dic);
1662 /* do the same for the right operand */
1665 IS_ITEMP(IC_RIGHT(ic)) &&
1666 OP_SYMBOL(IC_RIGHT(ic))->liveTo <= ic->seq) {
1667 iCode *dic = findAssignToSym(IC_RIGHT(ic),ic);
1673 /* if this is a subtraction & the result
1674 is a true symbol in far space then don't pack */
1675 if (ic->op == '-' && IS_TRUE_SYMOP(IC_RESULT(dic))) {
1676 link *etype =getSpec(operandType(IC_RESULT(dic)));
1677 if (IN_FARSPACE(SPEC_OCLS(etype)))
1680 /* found it we need to remove it from the
1682 for ( sic = dic; sic != ic ; sic = sic->next )
1683 bitVectUnSetBit(sic->rlive,IC_RIGHT(ic)->key);
1685 IC_RIGHT(ic)->operand.symOperand =
1686 IC_RIGHT(dic)->operand.symOperand;
1687 IC_RIGHT(ic)->key = IC_RIGHT(dic)->operand.symOperand->key;
1689 remiCodeFromeBBlock(ebp,dic);
1696 #define IS_OP_RUONLY(x) (x && IS_SYMOP(x) && OP_SYMBOL(x)->ruonly)
1699 /*-----------------------------------------------------------------*/
1700 /* packRegsForOneuse : - will reduce some registers for single Use */
1701 /*-----------------------------------------------------------------*/
1702 static iCode *packRegsForOneuse (iCode *ic, operand *op , eBBlock *ebp)
1707 /* if returning a literal then do nothing */
1711 /* only upto 2 bytes since we cannot predict
1712 the usage of b, & acc */
1713 if (getSize(operandType(op)) > 2 &&
1718 /* this routine will mark the a symbol as used in one
1719 instruction use only && if the defintion is local
1720 (ie. within the basic block) && has only one definition &&
1721 that definiion is either a return value from a
1722 function or does not contain any variables in
1724 uses = bitVectCopy(OP_USES(op));
1725 bitVectUnSetBit(uses,ic->key); /* take away this iCode */
1726 if (!bitVectIsZero(uses)) /* has other uses */
1729 /* if it has only one defintion */
1730 if (bitVectnBitsOn(OP_DEFS(op)) > 1)
1731 return NULL ; /* has more than one definition */
1733 /* get the that definition */
1735 hTabItemWithKey(iCodehTab,
1736 bitVectFirstBit(OP_DEFS(op)))))
1739 /* found the definition now check if it is local */
1740 if (dic->seq < ebp->fSeq ||
1741 dic->seq > ebp->lSeq)
1742 return NULL ; /* non-local */
1744 /* now check if it is the return from
1746 if (dic->op == CALL || dic->op == PCALL ) {
1747 if (ic->op != SEND && ic->op != RETURN) {
1748 OP_SYMBOL(op)->ruonly = 1;
1755 /* otherwise check that the definition does
1756 not contain any symbols in far space */
1757 if (isOperandInFarSpace(IC_LEFT(dic)) ||
1758 isOperandInFarSpace(IC_RIGHT(dic)) ||
1759 IS_OP_RUONLY(IC_LEFT(ic)) ||
1760 IS_OP_RUONLY(IC_RIGHT(ic)) ) {
1764 /* if pointer set then make sure the pointer
1766 if (POINTER_SET(dic) &&
1767 !IS_DATA_PTR(aggrToPtr(operandType(IC_RESULT(dic)),FALSE)))
1770 if (POINTER_GET(dic) &&
1771 !IS_DATA_PTR(aggrToPtr(operandType(IC_LEFT(dic)),FALSE)))
1776 /* also make sure the intervenening instructions
1777 don't have any thing in far space */
1778 for (dic = dic->next ; dic && dic != ic ; dic = dic->next) {
1780 /* if there is an intervening function call then no */
1781 if (dic->op == CALL || dic->op == PCALL)
1783 /* if pointer set then make sure the pointer
1785 if (POINTER_SET(dic) &&
1786 !IS_DATA_PTR(aggrToPtr(operandType(IC_RESULT(dic)),FALSE)))
1789 if (POINTER_GET(dic) &&
1790 !IS_DATA_PTR(aggrToPtr(operandType(IC_LEFT(dic)),FALSE)))
1793 /* if address of & the result is remat the okay */
1794 if (dic->op == ADDRESS_OF &&
1795 OP_SYMBOL(IC_RESULT(dic))->remat)
1798 /* if operand has size of three or more & this
1799 operation is a '*','/' or '%' then 'b' may
1801 if (( dic->op == '%' || dic->op == '/' || dic->op == '*') &&
1802 getSize(aggrToPtr(operandType(op),FALSE)) >= 3)
1805 /* if left or right or result is in far space */
1806 if (isOperandInFarSpace(IC_LEFT(dic)) ||
1807 isOperandInFarSpace(IC_RIGHT(dic)) ||
1808 isOperandInFarSpace(IC_RESULT(dic)) ||
1809 IS_OP_RUONLY(IC_LEFT(dic)) ||
1810 IS_OP_RUONLY(IC_RIGHT(dic)) ||
1811 IS_OP_RUONLY(IC_RESULT(dic)) ) {
1816 OP_SYMBOL(op)->ruonly = 1;
1821 /*-----------------------------------------------------------------*/
1822 /* isBitwiseOptimizable - requirements of JEAN LOUIS VERN */
1823 /*-----------------------------------------------------------------*/
1824 static bool isBitwiseOptimizable (iCode *ic)
1826 link *ltype = getSpec(operandType(IC_LEFT(ic)));
1827 link *rtype = getSpec(operandType(IC_RIGHT(ic)));
1829 /* bitwise operations are considered optimizable
1830 under the following conditions (Jean-Louis VERN)
1842 if ( IS_LITERAL(rtype) ||
1843 (IS_BITVAR(ltype) && IN_BITSPACE(SPEC_OCLS(ltype))))
1849 /*-----------------------------------------------------------------*/
1850 /* packRegsForAccUse - pack registers for acc use */
1851 /*-----------------------------------------------------------------*/
1852 static void packRegsForAccUse (iCode *ic)
1856 /* if + or - then it has to be one byte result */
1857 if ((ic->op == '+' || ic->op == '-')
1858 && getSize(operandType(IC_RESULT(ic))) > 1)
1861 /* if shift operation make sure right side is not a literal */
1862 if (ic->op == RIGHT_OP &&
1863 ( isOperandLiteral(IC_RIGHT(ic)) ||
1864 getSize(operandType(IC_RESULT(ic))) > 1))
1867 if (ic->op == LEFT_OP &&
1868 ( isOperandLiteral(IC_RIGHT(ic)) ||
1869 getSize(operandType(IC_RESULT(ic))) > 1))
1873 /* has only one definition */
1874 if (bitVectnBitsOn(OP_DEFS(IC_RESULT(ic))) > 1)
1877 /* has only one use */
1878 if (bitVectnBitsOn(OP_USES(IC_RESULT(ic))) > 1)
1881 /* and the usage immediately follows this iCode */
1882 if (!(uic = hTabItemWithKey(iCodehTab,
1883 bitVectFirstBit(OP_USES(IC_RESULT(ic))))))
1886 if (ic->next != uic)
1889 /* if it is a conditional branch then we definitely can */
1890 if (uic->op == IFX )
1893 if ( uic->op == JUMPTABLE )
1896 /* if the usage is not is an assignment
1897 or an arithmetic / bitwise / shift operation then not */
1898 if (POINTER_SET(uic) &&
1899 getSize(aggrToPtr(operandType(IC_RESULT(uic)),FALSE)) > 1)
1902 if (uic->op != '=' &&
1903 !IS_ARITHMETIC_OP(uic) &&
1904 !IS_BITWISE_OP(uic) &&
1905 uic->op != LEFT_OP &&
1906 uic->op != RIGHT_OP )
1909 /* if used in ^ operation then make sure right is not a
1911 if (uic->op == '^' && isOperandLiteral(IC_RIGHT(uic)))
1914 /* if shift operation make sure right side is not a literal */
1915 if (uic->op == RIGHT_OP &&
1916 ( isOperandLiteral(IC_RIGHT(uic)) ||
1917 getSize(operandType(IC_RESULT(uic))) > 1))
1920 if (uic->op == LEFT_OP &&
1921 ( isOperandLiteral(IC_RIGHT(uic)) ||
1922 getSize(operandType(IC_RESULT(uic))) > 1))
1925 /* make sure that the result of this icode is not on the
1926 stack, since acc is used to compute stack offset */
1927 if (IS_TRUE_SYMOP(IC_RESULT(uic)) &&
1928 OP_SYMBOL(IC_RESULT(uic))->onStack)
1931 /* if either one of them in far space then we cannot */
1932 if ((IS_TRUE_SYMOP(IC_LEFT(uic)) &&
1933 isOperandInFarSpace(IC_LEFT(uic))) ||
1934 (IS_TRUE_SYMOP(IC_RIGHT(uic)) &&
1935 isOperandInFarSpace(IC_RIGHT(uic))))
1938 /* if the usage has only one operand then we can */
1939 if (IC_LEFT(uic) == NULL ||
1940 IC_RIGHT(uic) == NULL)
1943 /* make sure this is on the left side if not
1944 a '+' since '+' is commutative */
1945 if (ic->op != '+' &&
1946 IC_LEFT(uic)->key != IC_RESULT(ic)->key)
1949 /* if one of them is a literal then we can */
1950 if ((IC_LEFT(uic) && IS_OP_LITERAL(IC_LEFT(uic))) ||
1951 (IC_RIGHT(uic) && IS_OP_LITERAL(IC_RIGHT(uic)))) {
1952 OP_SYMBOL(IC_RESULT(ic))->accuse = 1;
1956 /* if the other one is not on stack then we can */
1957 if (IC_LEFT(uic)->key == IC_RESULT(ic)->key &&
1958 (IS_ITEMP(IC_RIGHT(uic)) ||
1959 (IS_TRUE_SYMOP(IC_RIGHT(uic)) &&
1960 !OP_SYMBOL(IC_RIGHT(uic))->onStack)))
1963 if (IC_RIGHT(uic)->key == IC_RESULT(ic)->key &&
1964 (IS_ITEMP(IC_LEFT(uic)) ||
1965 (IS_TRUE_SYMOP(IC_LEFT(uic)) &&
1966 !OP_SYMBOL(IC_LEFT(uic))->onStack)))
1972 OP_SYMBOL(IC_RESULT(ic))->accuse = 1;
1977 /*-----------------------------------------------------------------*/
1978 /* packForPush - hueristics to reduce iCode for pushing */
1979 /*-----------------------------------------------------------------*/
1980 static void packForPush(iCode *ic, eBBlock *ebp)
1984 if (ic->op != IPUSH || !IS_ITEMP(IC_LEFT(ic)))
1987 /* must have only definition & one usage */
1988 if (bitVectnBitsOn(OP_DEFS(IC_LEFT(ic))) != 1 ||
1989 bitVectnBitsOn(OP_USES(IC_LEFT(ic))) != 1 )
1992 /* find the definition */
1993 if (!(dic = hTabItemWithKey(iCodehTab,
1994 bitVectFirstBit(OP_DEFS(IC_LEFT(ic))))))
1997 if (dic->op != '=' || POINTER_SET(dic) || IS_ITEMP(IC_RESULT(dic)))
2000 /* we now we know that it has one & only one def & use
2001 and the that the definition is an assignment */
2002 IC_LEFT(ic) = IC_RIGHT(dic);
2004 remiCodeFromeBBlock(ebp,dic);
2007 /*-----------------------------------------------------------------*/
2008 /* packRegisters - does some transformations to reduce register */
2010 /*-----------------------------------------------------------------*/
2011 static void packRegisters (eBBlock *ebp)
2020 /* look for assignments of the form */
2021 /* iTempNN = TRueSym (someoperation) SomeOperand */
2023 /* TrueSym := iTempNN:1 */
2024 for ( ic = ebp->sch ; ic ; ic = ic->next ) {
2027 /* find assignment of the form TrueSym := iTempNN:1 */
2028 if (ic->op == '=' && !POINTER_SET(ic))
2029 change += packRegsForAssign(ic,ebp);
2036 for ( ic = ebp->sch ; ic ; ic = ic->next ) {
2038 /* if this is an itemp & result of a address of a true sym
2039 then mark this as rematerialisable */
2040 if (ic->op == ADDRESS_OF &&
2041 IS_ITEMP(IC_RESULT(ic)) &&
2042 IS_TRUE_SYMOP(IC_LEFT(ic)) &&
2043 bitVectnBitsOn(OP_DEFS(IC_RESULT(ic))) == 1 &&
2044 !OP_SYMBOL(IC_LEFT(ic))->onStack ) {
2046 OP_SYMBOL(IC_RESULT(ic))->remat = 1;
2047 OP_SYMBOL(IC_RESULT(ic))->rematiCode = ic;
2048 OP_SYMBOL(IC_RESULT(ic))->usl.spillLoc = NULL;
2052 /* if straight assignment then carry remat flag if
2053 this is the only definition */
2054 if (ic->op == '=' &&
2056 IS_SYMOP(IC_RIGHT(ic)) &&
2057 OP_SYMBOL(IC_RIGHT(ic))->remat &&
2058 bitVectnBitsOn(OP_SYMBOL(IC_RESULT(ic))->defs) <= 1) {
2060 OP_SYMBOL(IC_RESULT(ic))->remat =
2061 OP_SYMBOL(IC_RIGHT(ic))->remat;
2062 OP_SYMBOL(IC_RESULT(ic))->rematiCode =
2063 OP_SYMBOL(IC_RIGHT(ic))->rematiCode ;
2066 /* if this is a +/- operation with a rematerizable
2067 then mark this as rematerializable as well only
2068 if the literal value is within the range -255 and + 255
2069 the assembler cannot handle it other wise */
2070 if ((ic->op == '+' || ic->op == '-') &&
2072 (IS_SYMOP(IC_LEFT(ic)) &&
2073 IS_ITEMP(IC_RESULT(ic)) &&
2074 OP_SYMBOL(IC_LEFT(ic))->remat &&
2075 bitVectnBitsOn(OP_DEFS(IC_RESULT(ic))) == 1 &&
2076 IS_OP_LITERAL(IC_RIGHT(ic))) ) {
2078 int i = operandLitValue(IC_RIGHT(ic));
2079 if ( i < 255 && i > -255) {
2080 OP_SYMBOL(IC_RESULT(ic))->remat = 1;
2081 OP_SYMBOL(IC_RESULT(ic))->rematiCode = ic;
2082 OP_SYMBOL(IC_RESULT(ic))->usl.spillLoc = NULL;
2086 /* mark the pointer usages */
2087 if (POINTER_SET(ic))
2088 OP_SYMBOL(IC_RESULT(ic))->uptr = 1;
2090 if (POINTER_GET(ic))
2091 OP_SYMBOL(IC_LEFT(ic))->uptr = 1;
2093 if (!SKIP_IC2(ic)) {
2094 /* if we are using a symbol on the stack
2095 then we should say mcs51_ptrRegReq */
2096 if (ic->op == IFX && IS_SYMOP(IC_COND(ic)))
2097 mcs51_ptrRegReq += ((OP_SYMBOL(IC_COND(ic))->onStack ||
2098 OP_SYMBOL(IC_COND(ic))->iaccess) ? 1 : 0);
2100 if (ic->op == JUMPTABLE && IS_SYMOP(IC_JTCOND(ic)))
2101 mcs51_ptrRegReq += ((OP_SYMBOL(IC_JTCOND(ic))->onStack ||
2102 OP_SYMBOL(IC_JTCOND(ic))->iaccess) ? 1 : 0);
2104 if (IS_SYMOP(IC_LEFT(ic)))
2105 mcs51_ptrRegReq += ((OP_SYMBOL(IC_LEFT(ic))->onStack ||
2106 OP_SYMBOL(IC_LEFT(ic))->iaccess) ? 1 : 0);
2107 if (IS_SYMOP(IC_RIGHT(ic)))
2108 mcs51_ptrRegReq += ((OP_SYMBOL(IC_RIGHT(ic))->onStack ||
2109 OP_SYMBOL(IC_RIGHT(ic))->iaccess) ? 1 : 0);
2110 if (IS_SYMOP(IC_RESULT(ic)))
2111 mcs51_ptrRegReq += ((OP_SYMBOL(IC_RESULT(ic))->onStack ||
2112 OP_SYMBOL(IC_RESULT(ic))->iaccess) ? 1 : 0);
2116 /* if the condition of an if instruction
2117 is defined in the previous instruction then
2118 mark the itemp as a conditional */
2119 if ((IS_CONDITIONAL(ic) ||
2120 ( ( ic->op == BITWISEAND ||
2123 isBitwiseOptimizable(ic))) &&
2124 ic->next && ic->next->op == IFX &&
2125 isOperandEqual(IC_RESULT(ic),IC_COND(ic->next)) &&
2126 OP_SYMBOL(IC_RESULT(ic))->liveTo <= ic->next->seq) {
2128 OP_SYMBOL(IC_RESULT(ic))->regType = REG_CND;
2132 /* reduce for support function calls */
2133 if (ic->supportRtn || ic->op == '+' || ic->op == '-' )
2134 packRegsForSupport (ic,ebp);
2136 /* some cases the redundant moves can
2137 can be eliminated for return statements */
2138 if ((ic->op == RETURN || ic->op == SEND) &&
2139 !isOperandInFarSpace(IC_LEFT(ic)) &&
2141 packRegsForOneuse (ic,IC_LEFT(ic),ebp);
2143 /* if pointer set & left has a size more than
2144 one and right is not in far space */
2145 if (POINTER_SET(ic) &&
2146 !isOperandInFarSpace(IC_RIGHT(ic)) &&
2147 !OP_SYMBOL(IC_RESULT(ic))->remat &&
2148 !IS_OP_RUONLY(IC_RIGHT(ic)) &&
2149 getSize(aggrToPtr(operandType(IC_RESULT(ic)),FALSE)) > 1 )
2151 packRegsForOneuse (ic,IC_RESULT(ic),ebp);
2153 /* if pointer get */
2154 if (POINTER_GET(ic) &&
2155 !isOperandInFarSpace(IC_RESULT(ic))&&
2156 !OP_SYMBOL(IC_LEFT(ic))->remat &&
2157 !IS_OP_RUONLY(IC_RESULT(ic)) &&
2158 getSize(aggrToPtr(operandType(IC_LEFT(ic)),FALSE)) > 1 )
2160 packRegsForOneuse (ic,IC_LEFT(ic),ebp);
2163 /* if this is cast for intergral promotion then
2164 check if only use of the definition of the
2165 operand being casted/ if yes then replace
2166 the result of that arithmetic operation with
2167 this result and get rid of the cast */
2168 if (ic->op == CAST) {
2169 link *fromType = operandType(IC_RIGHT(ic));
2170 link *toType = operandType(IC_LEFT(ic));
2172 if (IS_INTEGRAL(fromType) && IS_INTEGRAL(toType) &&
2173 getSize(fromType) != getSize(toType) ) {
2175 iCode *dic = packRegsForOneuse(ic,IC_RIGHT(ic),ebp);
2177 if (IS_ARITHMETIC_OP(dic)) {
2178 IC_RESULT(dic) = IC_RESULT(ic);
2179 remiCodeFromeBBlock(ebp,ic);
2182 OP_SYMBOL(IC_RIGHT(ic))->ruonly = 0;
2186 /* if the type from and type to are the same
2187 then if this is the only use then packit */
2188 if (checkType(operandType(IC_RIGHT(ic)),
2189 operandType(IC_LEFT(ic))) == 1) {
2190 iCode *dic = packRegsForOneuse (ic,IC_RIGHT(ic),ebp);
2192 IC_RESULT(dic) = IC_RESULT(ic);
2193 remiCodeFromeBBlock(ebp,ic);
2201 iTempNN := (some variable in farspace) V1
2206 if (ic->op == IPUSH ) {
2207 packForPush(ic,ebp);
2211 /* pack registers for accumulator use, when the
2212 result of an arithmetic or bit wise operation
2213 has only one use, that use is immediately following
2214 the defintion and the using iCode has only one
2215 operand or has two operands but one is literal &
2216 the result of that operation is not on stack then
2217 we can leave the result of this operation in acc:b
2219 if ((IS_ARITHMETIC_OP(ic)
2221 || IS_BITWISE_OP(ic)
2223 || ic->op == LEFT_OP || ic->op == RIGHT_OP
2226 IS_ITEMP(IC_RESULT(ic)) &&
2227 getSize(operandType(IC_RESULT(ic))) <= 2)
2229 packRegsForAccUse (ic);
2234 /*-----------------------------------------------------------------*/
2235 /* assignRegisters - assigns registers to each live range as need */
2236 /*-----------------------------------------------------------------*/
2237 void mcs51_assignRegisters (eBBlock **ebbs, int count)
2242 setToNull((void *)&_G.funcrUsed);
2243 mcs51_ptrRegReq = _G.stackExtend = _G.dataExtend = 0;
2244 /* if not register extentions then reduce number
2246 if (options.regExtend)
2251 /* change assignments this will remove some
2252 live ranges reducing some register pressure */
2253 for (i = 0 ; i < count ;i++ )
2254 packRegisters (ebbs[i]);
2256 if (options.dump_pack)
2257 dumpEbbsToFileExt(".dumppack",ebbs,count);
2259 /* first determine for each live range the number of
2260 registers & the type of registers required for each */
2263 /* and serially allocate registers */
2264 serialRegAssign(ebbs,count);
2266 /* if stack was extended then tell the user */
2267 if (_G.stackExtend) {
2268 /* werror(W_TOOMANY_SPILS,"stack", */
2269 /* _G.stackExtend,currFunc->name,""); */
2270 _G.stackExtend = 0 ;
2273 if (_G.dataExtend) {
2274 /* werror(W_TOOMANY_SPILS,"data space", */
2275 /* _G.dataExtend,currFunc->name,""); */
2279 /* after that create the register mask
2280 for each of the instruction */
2281 createRegMask (ebbs,count);
2283 /* redo that offsets for stacked automatic variables */
2284 redoStackOffsets ();
2286 if (options.dump_rassgn)
2287 dumpEbbsToFileExt(".dumprassgn",ebbs,count);
2289 /* now get back the chain */
2290 ic = iCodeLabelOptimize(iCodeFromeBBlock (ebbs,count));
2295 /* free up any _G.stackSpil locations allocated */
2296 applyToSet(_G.stackSpil,deallocStackSpil);
2298 setToNull((void **)&_G.stackSpil);
2299 setToNull((void **)&_G.spiltSet);
2300 /* mark all registers as free */