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);
1557 hTabDeleteItem (&iCodehTab,ic->key,ic,DELETE_ITEM,NULL);
1562 /*-----------------------------------------------------------------*/
1563 /* findAssignToSym : scanning backwards looks for first assig found*/
1564 /*-----------------------------------------------------------------*/
1565 static iCode *findAssignToSym (operand *op,iCode *ic)
1569 for (dic = ic->prev ; dic ; dic = dic->prev) {
1571 /* if definition by assignment */
1572 if (dic->op == '=' &&
1573 !POINTER_SET(dic) &&
1574 IC_RESULT(dic)->key == op->key
1575 /* && IS_TRUE_SYMOP(IC_RIGHT(dic)) */
1578 /* we are interested only if defined in far space */
1579 /* or in stack space in case of + & - */
1581 /* if assigned to a non-symbol then return
1583 if (!IS_SYMOP(IC_RIGHT(dic)))
1586 /* if the symbol is in far space then
1588 if (isOperandInFarSpace(IC_RIGHT(dic)))
1591 /* for + & - operations make sure that
1592 if it is on the stack it is the same
1593 as one of the three operands */
1594 if ((ic->op == '+' || ic->op == '-') &&
1595 OP_SYMBOL(IC_RIGHT(dic))->onStack) {
1597 if ( IC_RESULT(ic)->key != IC_RIGHT(dic)->key &&
1598 IC_LEFT(ic)->key != IC_RIGHT(dic)->key &&
1599 IC_RIGHT(ic)->key != IC_RIGHT(dic)->key)
1607 /* if we find an usage then we cannot delete it */
1608 if (IC_LEFT(dic) && IC_LEFT(dic)->key == op->key)
1611 if (IC_RIGHT(dic) && IC_RIGHT(dic)->key == op->key)
1614 if (POINTER_SET(dic) && IC_RESULT(dic)->key == op->key)
1618 /* now make sure that the right side of dic
1619 is not defined between ic & dic */
1621 iCode *sic = dic->next ;
1623 for (; sic != ic ; sic = sic->next)
1624 if (IC_RESULT(sic) &&
1625 IC_RESULT(sic)->key == IC_RIGHT(dic)->key)
1634 /*-----------------------------------------------------------------*/
1635 /* packRegsForSupport :- reduce some registers for support calls */
1636 /*-----------------------------------------------------------------*/
1637 static int packRegsForSupport (iCode *ic, eBBlock *ebp)
1640 /* for the left & right operand :- look to see if the
1641 left was assigned a true symbol in far space in that
1642 case replace them */
1643 if (IS_ITEMP(IC_LEFT(ic)) &&
1644 OP_SYMBOL(IC_LEFT(ic))->liveTo <= ic->seq) {
1645 iCode *dic = findAssignToSym(IC_LEFT(ic),ic);
1651 /* found it we need to remove it from the
1653 for ( sic = dic; sic != ic ; sic = sic->next )
1654 bitVectUnSetBit(sic->rlive,IC_LEFT(ic)->key);
1656 IC_LEFT(ic)->operand.symOperand =
1657 IC_RIGHT(dic)->operand.symOperand;
1658 IC_LEFT(ic)->key = IC_RIGHT(dic)->operand.symOperand->key;
1659 remiCodeFromeBBlock(ebp,dic);
1660 hTabDeleteItem (&iCodehTab,dic->key,dic,DELETE_ITEM,NULL);
1664 /* do the same for the right operand */
1667 IS_ITEMP(IC_RIGHT(ic)) &&
1668 OP_SYMBOL(IC_RIGHT(ic))->liveTo <= ic->seq) {
1669 iCode *dic = findAssignToSym(IC_RIGHT(ic),ic);
1675 /* if this is a subtraction & the result
1676 is a true symbol in far space then don't pack */
1677 if (ic->op == '-' && IS_TRUE_SYMOP(IC_RESULT(dic))) {
1678 link *etype =getSpec(operandType(IC_RESULT(dic)));
1679 if (IN_FARSPACE(SPEC_OCLS(etype)))
1682 /* found it we need to remove it from the
1684 for ( sic = dic; sic != ic ; sic = sic->next )
1685 bitVectUnSetBit(sic->rlive,IC_RIGHT(ic)->key);
1687 IC_RIGHT(ic)->operand.symOperand =
1688 IC_RIGHT(dic)->operand.symOperand;
1689 IC_RIGHT(ic)->key = IC_RIGHT(dic)->operand.symOperand->key;
1691 remiCodeFromeBBlock(ebp,dic);
1692 hTabDeleteItem (&iCodehTab,dic->key,dic,DELETE_ITEM,NULL);
1699 #define IS_OP_RUONLY(x) (x && IS_SYMOP(x) && OP_SYMBOL(x)->ruonly)
1702 /*-----------------------------------------------------------------*/
1703 /* packRegsForOneuse : - will reduce some registers for single Use */
1704 /*-----------------------------------------------------------------*/
1705 static iCode *packRegsForOneuse (iCode *ic, operand *op , eBBlock *ebp)
1710 /* if returning a literal then do nothing */
1714 /* only upto 2 bytes since we cannot predict
1715 the usage of b, & acc */
1716 if (getSize(operandType(op)) > 2 &&
1721 /* this routine will mark the a symbol as used in one
1722 instruction use only && if the defintion is local
1723 (ie. within the basic block) && has only one definition &&
1724 that definiion is either a return value from a
1725 function or does not contain any variables in
1727 uses = bitVectCopy(OP_USES(op));
1728 bitVectUnSetBit(uses,ic->key); /* take away this iCode */
1729 if (!bitVectIsZero(uses)) /* has other uses */
1732 /* if it has only one defintion */
1733 if (bitVectnBitsOn(OP_DEFS(op)) > 1)
1734 return NULL ; /* has more than one definition */
1736 /* get the that definition */
1738 hTabItemWithKey(iCodehTab,
1739 bitVectFirstBit(OP_DEFS(op)))))
1742 /* found the definition now check if it is local */
1743 if (dic->seq < ebp->fSeq ||
1744 dic->seq > ebp->lSeq)
1745 return NULL ; /* non-local */
1747 /* now check if it is the return from
1749 if (dic->op == CALL || dic->op == PCALL ) {
1750 if (ic->op != SEND && ic->op != RETURN) {
1751 OP_SYMBOL(op)->ruonly = 1;
1758 /* otherwise check that the definition does
1759 not contain any symbols in far space */
1760 if (isOperandInFarSpace(IC_LEFT(dic)) ||
1761 isOperandInFarSpace(IC_RIGHT(dic)) ||
1762 IS_OP_RUONLY(IC_LEFT(ic)) ||
1763 IS_OP_RUONLY(IC_RIGHT(ic)) ) {
1767 /* if pointer set then make sure the pointer
1769 if (POINTER_SET(dic) &&
1770 !IS_DATA_PTR(aggrToPtr(operandType(IC_RESULT(dic)),FALSE)))
1773 if (POINTER_GET(dic) &&
1774 !IS_DATA_PTR(aggrToPtr(operandType(IC_LEFT(dic)),FALSE)))
1779 /* also make sure the intervenening instructions
1780 don't have any thing in far space */
1781 for (dic = dic->next ; dic && dic != ic ; dic = dic->next) {
1783 /* if there is an intervening function call then no */
1784 if (dic->op == CALL || dic->op == PCALL)
1786 /* if pointer set then make sure the pointer
1788 if (POINTER_SET(dic) &&
1789 !IS_DATA_PTR(aggrToPtr(operandType(IC_RESULT(dic)),FALSE)))
1792 if (POINTER_GET(dic) &&
1793 !IS_DATA_PTR(aggrToPtr(operandType(IC_LEFT(dic)),FALSE)))
1796 /* if address of & the result is remat the okay */
1797 if (dic->op == ADDRESS_OF &&
1798 OP_SYMBOL(IC_RESULT(dic))->remat)
1801 /* if operand has size of three or more & this
1802 operation is a '*','/' or '%' then 'b' may
1804 if (( dic->op == '%' || dic->op == '/' || dic->op == '*') &&
1805 getSize(operandType(op)) >= 3)
1808 /* if left or right or result is in far space */
1809 if (isOperandInFarSpace(IC_LEFT(dic)) ||
1810 isOperandInFarSpace(IC_RIGHT(dic)) ||
1811 isOperandInFarSpace(IC_RESULT(dic)) ||
1812 IS_OP_RUONLY(IC_LEFT(dic)) ||
1813 IS_OP_RUONLY(IC_RIGHT(dic)) ||
1814 IS_OP_RUONLY(IC_RESULT(dic)) ) {
1819 OP_SYMBOL(op)->ruonly = 1;
1824 /*-----------------------------------------------------------------*/
1825 /* isBitwiseOptimizable - requirements of JEAN LOUIS VERN */
1826 /*-----------------------------------------------------------------*/
1827 static bool isBitwiseOptimizable (iCode *ic)
1829 link *ltype = getSpec(operandType(IC_LEFT(ic)));
1830 link *rtype = getSpec(operandType(IC_RIGHT(ic)));
1832 /* bitwise operations are considered optimizable
1833 under the following conditions (Jean-Louis VERN)
1845 if ( IS_LITERAL(rtype) ||
1846 (IS_BITVAR(ltype) && IN_BITSPACE(SPEC_OCLS(ltype))))
1852 /*-----------------------------------------------------------------*/
1853 /* packRegsForAccUse - pack registers for acc use */
1854 /*-----------------------------------------------------------------*/
1855 static void packRegsForAccUse (iCode *ic)
1859 /* if + or - then it has to be one byte result */
1860 if ((ic->op == '+' || ic->op == '-')
1861 && getSize(operandType(IC_RESULT(ic))) > 1)
1864 /* if shift operation make sure right side is not a literal */
1865 if (ic->op == RIGHT_OP &&
1866 ( isOperandLiteral(IC_RIGHT(ic)) ||
1867 getSize(operandType(IC_RESULT(ic))) > 1))
1870 if (ic->op == LEFT_OP &&
1871 ( isOperandLiteral(IC_RIGHT(ic)) ||
1872 getSize(operandType(IC_RESULT(ic))) > 1))
1876 /* has only one definition */
1877 if (bitVectnBitsOn(OP_DEFS(IC_RESULT(ic))) > 1)
1880 /* has only one use */
1881 if (bitVectnBitsOn(OP_USES(IC_RESULT(ic))) > 1)
1884 /* and the usage immediately follows this iCode */
1885 if (!(uic = hTabItemWithKey(iCodehTab,
1886 bitVectFirstBit(OP_USES(IC_RESULT(ic))))))
1889 if (ic->next != uic)
1892 /* if it is a conditional branch then we definitely can */
1893 if (uic->op == IFX )
1896 if ( uic->op == JUMPTABLE )
1899 /* if the usage is not is an assignment
1900 or an arithmetic / bitwise / shift operation then not */
1901 if (POINTER_SET(uic) &&
1902 getSize(aggrToPtr(operandType(IC_RESULT(uic)),FALSE)) > 1)
1905 if (uic->op != '=' &&
1906 !IS_ARITHMETIC_OP(uic) &&
1907 !IS_BITWISE_OP(uic) &&
1908 uic->op != LEFT_OP &&
1909 uic->op != RIGHT_OP )
1912 /* if used in ^ operation then make sure right is not a
1914 if (uic->op == '^' && isOperandLiteral(IC_RIGHT(uic)))
1917 /* if shift operation make sure right side is not a literal */
1918 if (uic->op == RIGHT_OP &&
1919 ( isOperandLiteral(IC_RIGHT(uic)) ||
1920 getSize(operandType(IC_RESULT(uic))) > 1))
1923 if (uic->op == LEFT_OP &&
1924 ( isOperandLiteral(IC_RIGHT(uic)) ||
1925 getSize(operandType(IC_RESULT(uic))) > 1))
1928 /* make sure that the result of this icode is not on the
1929 stack, since acc is used to compute stack offset */
1930 if (IS_TRUE_SYMOP(IC_RESULT(uic)) &&
1931 OP_SYMBOL(IC_RESULT(uic))->onStack)
1934 /* if either one of them in far space then we cannot */
1935 if ((IS_TRUE_SYMOP(IC_LEFT(uic)) &&
1936 isOperandInFarSpace(IC_LEFT(uic))) ||
1937 (IS_TRUE_SYMOP(IC_RIGHT(uic)) &&
1938 isOperandInFarSpace(IC_RIGHT(uic))))
1941 /* if the usage has only one operand then we can */
1942 if (IC_LEFT(uic) == NULL ||
1943 IC_RIGHT(uic) == NULL)
1946 /* make sure this is on the left side if not
1947 a '+' since '+' is commutative */
1948 if (ic->op != '+' &&
1949 IC_LEFT(uic)->key != IC_RESULT(ic)->key)
1952 /* if one of them is a literal then we can */
1953 if ((IC_LEFT(uic) && IS_OP_LITERAL(IC_LEFT(uic))) ||
1954 (IC_RIGHT(uic) && IS_OP_LITERAL(IC_RIGHT(uic)))) {
1955 OP_SYMBOL(IC_RESULT(ic))->accuse = 1;
1959 /* if the other one is not on stack then we can */
1960 if (IC_LEFT(uic)->key == IC_RESULT(ic)->key &&
1961 (IS_ITEMP(IC_RIGHT(uic)) ||
1962 (IS_TRUE_SYMOP(IC_RIGHT(uic)) &&
1963 !OP_SYMBOL(IC_RIGHT(uic))->onStack)))
1966 if (IC_RIGHT(uic)->key == IC_RESULT(ic)->key &&
1967 (IS_ITEMP(IC_LEFT(uic)) ||
1968 (IS_TRUE_SYMOP(IC_LEFT(uic)) &&
1969 !OP_SYMBOL(IC_LEFT(uic))->onStack)))
1975 OP_SYMBOL(IC_RESULT(ic))->accuse = 1;
1980 /*-----------------------------------------------------------------*/
1981 /* packForPush - hueristics to reduce iCode for pushing */
1982 /*-----------------------------------------------------------------*/
1983 static void packForPush(iCode *ic, eBBlock *ebp)
1987 if (ic->op != IPUSH || !IS_ITEMP(IC_LEFT(ic)))
1990 /* must have only definition & one usage */
1991 if (bitVectnBitsOn(OP_DEFS(IC_LEFT(ic))) != 1 ||
1992 bitVectnBitsOn(OP_USES(IC_LEFT(ic))) != 1 )
1995 /* find the definition */
1996 if (!(dic = hTabItemWithKey(iCodehTab,
1997 bitVectFirstBit(OP_DEFS(IC_LEFT(ic))))))
2000 if (dic->op != '=' || POINTER_SET(dic) || IS_ITEMP(IC_RESULT(dic)))
2003 /* we now we know that it has one & only one def & use
2004 and the that the definition is an assignment */
2005 IC_LEFT(ic) = IC_RIGHT(dic);
2007 remiCodeFromeBBlock(ebp,dic);
2008 hTabDeleteItem (&iCodehTab,dic->key,dic,DELETE_ITEM,NULL);
2011 /*-----------------------------------------------------------------*/
2012 /* packRegisters - does some transformations to reduce register */
2014 /*-----------------------------------------------------------------*/
2015 static void packRegisters (eBBlock *ebp)
2024 /* look for assignments of the form */
2025 /* iTempNN = TRueSym (someoperation) SomeOperand */
2027 /* TrueSym := iTempNN:1 */
2028 for ( ic = ebp->sch ; ic ; ic = ic->next ) {
2031 /* find assignment of the form TrueSym := iTempNN:1 */
2032 if (ic->op == '=' && !POINTER_SET(ic))
2033 change += packRegsForAssign(ic,ebp);
2040 for ( ic = ebp->sch ; ic ; ic = ic->next ) {
2042 /* if this is an itemp & result of a address of a true sym
2043 then mark this as rematerialisable */
2044 if (ic->op == ADDRESS_OF &&
2045 IS_ITEMP(IC_RESULT(ic)) &&
2046 IS_TRUE_SYMOP(IC_LEFT(ic)) &&
2047 bitVectnBitsOn(OP_DEFS(IC_RESULT(ic))) == 1 &&
2048 !OP_SYMBOL(IC_LEFT(ic))->onStack ) {
2050 OP_SYMBOL(IC_RESULT(ic))->remat = 1;
2051 OP_SYMBOL(IC_RESULT(ic))->rematiCode = ic;
2052 OP_SYMBOL(IC_RESULT(ic))->usl.spillLoc = NULL;
2056 /* if straight assignment then carry remat flag if
2057 this is the only definition */
2058 if (ic->op == '=' &&
2060 IS_SYMOP(IC_RIGHT(ic)) &&
2061 OP_SYMBOL(IC_RIGHT(ic))->remat &&
2062 bitVectnBitsOn(OP_SYMBOL(IC_RESULT(ic))->defs) <= 1) {
2064 OP_SYMBOL(IC_RESULT(ic))->remat =
2065 OP_SYMBOL(IC_RIGHT(ic))->remat;
2066 OP_SYMBOL(IC_RESULT(ic))->rematiCode =
2067 OP_SYMBOL(IC_RIGHT(ic))->rematiCode ;
2070 /* if this is a +/- operation with a rematerizable
2071 then mark this as rematerializable as well only
2072 if the literal value is within the range -255 and + 255
2073 the assembler cannot handle it other wise */
2074 if ((ic->op == '+' || ic->op == '-') &&
2076 (IS_SYMOP(IC_LEFT(ic)) &&
2077 IS_ITEMP(IC_RESULT(ic)) &&
2078 OP_SYMBOL(IC_LEFT(ic))->remat &&
2079 bitVectnBitsOn(OP_DEFS(IC_RESULT(ic))) == 1 &&
2080 IS_OP_LITERAL(IC_RIGHT(ic))) ) {
2082 int i = operandLitValue(IC_RIGHT(ic));
2083 if ( i < 255 && i > -255) {
2084 OP_SYMBOL(IC_RESULT(ic))->remat = 1;
2085 OP_SYMBOL(IC_RESULT(ic))->rematiCode = ic;
2086 OP_SYMBOL(IC_RESULT(ic))->usl.spillLoc = NULL;
2090 /* mark the pointer usages */
2091 if (POINTER_SET(ic))
2092 OP_SYMBOL(IC_RESULT(ic))->uptr = 1;
2094 if (POINTER_GET(ic))
2095 OP_SYMBOL(IC_LEFT(ic))->uptr = 1;
2097 if (!SKIP_IC2(ic)) {
2098 /* if we are using a symbol on the stack
2099 then we should say mcs51_ptrRegReq */
2100 if (ic->op == IFX && IS_SYMOP(IC_COND(ic)))
2101 mcs51_ptrRegReq += ((OP_SYMBOL(IC_COND(ic))->onStack ||
2102 OP_SYMBOL(IC_COND(ic))->iaccess) ? 1 : 0);
2104 if (ic->op == JUMPTABLE && IS_SYMOP(IC_JTCOND(ic)))
2105 mcs51_ptrRegReq += ((OP_SYMBOL(IC_JTCOND(ic))->onStack ||
2106 OP_SYMBOL(IC_JTCOND(ic))->iaccess) ? 1 : 0);
2108 if (IS_SYMOP(IC_LEFT(ic)))
2109 mcs51_ptrRegReq += ((OP_SYMBOL(IC_LEFT(ic))->onStack ||
2110 OP_SYMBOL(IC_LEFT(ic))->iaccess) ? 1 : 0);
2111 if (IS_SYMOP(IC_RIGHT(ic)))
2112 mcs51_ptrRegReq += ((OP_SYMBOL(IC_RIGHT(ic))->onStack ||
2113 OP_SYMBOL(IC_RIGHT(ic))->iaccess) ? 1 : 0);
2114 if (IS_SYMOP(IC_RESULT(ic)))
2115 mcs51_ptrRegReq += ((OP_SYMBOL(IC_RESULT(ic))->onStack ||
2116 OP_SYMBOL(IC_RESULT(ic))->iaccess) ? 1 : 0);
2120 /* if the condition of an if instruction
2121 is defined in the previous instruction then
2122 mark the itemp as a conditional */
2123 if ((IS_CONDITIONAL(ic) ||
2124 ( ( ic->op == BITWISEAND ||
2127 isBitwiseOptimizable(ic))) &&
2128 ic->next && ic->next->op == IFX &&
2129 isOperandEqual(IC_RESULT(ic),IC_COND(ic->next)) &&
2130 OP_SYMBOL(IC_RESULT(ic))->liveTo <= ic->next->seq) {
2132 OP_SYMBOL(IC_RESULT(ic))->regType = REG_CND;
2136 /* reduce for support function calls */
2137 if (ic->supportRtn || ic->op == '+' || ic->op == '-' )
2138 packRegsForSupport (ic,ebp);
2140 /* some cases the redundant moves can
2141 can be eliminated for return statements */
2142 if ((ic->op == RETURN || ic->op == SEND) &&
2143 !isOperandInFarSpace(IC_LEFT(ic)) &&
2145 packRegsForOneuse (ic,IC_LEFT(ic),ebp);
2147 /* if pointer set & left has a size more than
2148 one and right is not in far space */
2149 if (POINTER_SET(ic) &&
2150 !isOperandInFarSpace(IC_RIGHT(ic)) &&
2151 !OP_SYMBOL(IC_RESULT(ic))->remat &&
2152 !IS_OP_RUONLY(IC_RIGHT(ic)) &&
2153 getSize(aggrToPtr(operandType(IC_RESULT(ic)),FALSE)) > 1 )
2155 packRegsForOneuse (ic,IC_RESULT(ic),ebp);
2157 /* if pointer get */
2158 if (POINTER_GET(ic) &&
2159 !isOperandInFarSpace(IC_RESULT(ic))&&
2160 !OP_SYMBOL(IC_LEFT(ic))->remat &&
2161 !IS_OP_RUONLY(IC_RESULT(ic)) &&
2162 getSize(aggrToPtr(operandType(IC_LEFT(ic)),FALSE)) > 1 )
2164 packRegsForOneuse (ic,IC_LEFT(ic),ebp);
2167 /* if this is cast for intergral promotion then
2168 check if only use of the definition of the
2169 operand being casted/ if yes then replace
2170 the result of that arithmetic operation with
2171 this result and get rid of the cast */
2172 if (ic->op == CAST) {
2173 link *fromType = operandType(IC_RIGHT(ic));
2174 link *toType = operandType(IC_LEFT(ic));
2176 if (IS_INTEGRAL(fromType) && IS_INTEGRAL(toType) &&
2177 getSize(fromType) != getSize(toType) ) {
2179 iCode *dic = packRegsForOneuse(ic,IC_RIGHT(ic),ebp);
2181 if (IS_ARITHMETIC_OP(dic)) {
2182 IC_RESULT(dic) = IC_RESULT(ic);
2183 remiCodeFromeBBlock(ebp,ic);
2184 hTabDeleteItem (&iCodehTab,ic->key,ic,DELETE_ITEM,NULL);
2187 OP_SYMBOL(IC_RIGHT(ic))->ruonly = 0;
2191 /* if the type from and type to are the same
2192 then if this is the only use then packit */
2193 if (checkType(operandType(IC_RIGHT(ic)),
2194 operandType(IC_LEFT(ic))) == 1) {
2195 iCode *dic = packRegsForOneuse (ic,IC_RIGHT(ic),ebp);
2197 IC_RESULT(dic) = IC_RESULT(ic);
2198 remiCodeFromeBBlock(ebp,ic);
2199 hTabDeleteItem (&iCodehTab,ic->key,ic,DELETE_ITEM,NULL);
2207 iTempNN := (some variable in farspace) V1
2212 if (ic->op == IPUSH ) {
2213 packForPush(ic,ebp);
2217 /* pack registers for accumulator use, when the
2218 result of an arithmetic or bit wise operation
2219 has only one use, that use is immediately following
2220 the defintion and the using iCode has only one
2221 operand or has two operands but one is literal &
2222 the result of that operation is not on stack then
2223 we can leave the result of this operation in acc:b
2225 if ((IS_ARITHMETIC_OP(ic)
2227 || IS_BITWISE_OP(ic)
2229 || ic->op == LEFT_OP || ic->op == RIGHT_OP
2232 IS_ITEMP(IC_RESULT(ic)) &&
2233 getSize(operandType(IC_RESULT(ic))) <= 2)
2235 packRegsForAccUse (ic);
2240 /*-----------------------------------------------------------------*/
2241 /* assignRegisters - assigns registers to each live range as need */
2242 /*-----------------------------------------------------------------*/
2243 void mcs51_assignRegisters (eBBlock **ebbs, int count)
2248 setToNull((void *)&_G.funcrUsed);
2249 mcs51_ptrRegReq = _G.stackExtend = _G.dataExtend = 0;
2250 /* if not register extentions then reduce number
2252 if (options.regExtend)
2257 /* change assignments this will remove some
2258 live ranges reducing some register pressure */
2259 for (i = 0 ; i < count ;i++ )
2260 packRegisters (ebbs[i]);
2262 if (options.dump_pack)
2263 dumpEbbsToFileExt(".dumppack",ebbs,count);
2265 /* first determine for each live range the number of
2266 registers & the type of registers required for each */
2269 /* and serially allocate registers */
2270 serialRegAssign(ebbs,count);
2272 /* if stack was extended then tell the user */
2273 if (_G.stackExtend) {
2274 /* werror(W_TOOMANY_SPILS,"stack", */
2275 /* _G.stackExtend,currFunc->name,""); */
2276 _G.stackExtend = 0 ;
2279 if (_G.dataExtend) {
2280 /* werror(W_TOOMANY_SPILS,"data space", */
2281 /* _G.dataExtend,currFunc->name,""); */
2285 /* after that create the register mask
2286 for each of the instruction */
2287 createRegMask (ebbs,count);
2289 /* redo that offsets for stacked automatic variables */
2290 redoStackOffsets ();
2292 if (options.dump_rassgn)
2293 dumpEbbsToFileExt(".dumprassgn",ebbs,count);
2295 /* now get back the chain */
2296 ic = iCodeLabelOptimize(iCodeFromeBBlock (ebbs,count));
2301 /* free up any _G.stackSpil locations allocated */
2302 applyToSet(_G.stackSpil,deallocStackSpil);
2304 setToNull((void **)&_G.stackSpil);
2305 setToNull((void **)&_G.spiltSet);
2306 /* mark all registers as free */