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)
1078 /* else we assign registers to it */
1079 _G.regAssigned = bitVectSetBit(_G.regAssigned,sym->key);
1081 for (j = 0 ; j < sym->nRegs ;j++ ) {
1082 if (sym->regType == REG_PTR)
1083 sym->regs[j] = getRegPtr(ic,ebbs[i],sym);
1085 sym->regs[j] = getRegGpr(ic,ebbs[i],sym);
1087 /* if the allocation falied which means
1088 this was spilt then break */
1092 /* if it shares registers with operands make sure
1093 that they are in the same position */
1094 if (IC_LEFT(ic) && IS_SYMOP(IC_LEFT(ic)) &&
1095 OP_SYMBOL(IC_LEFT(ic))->nRegs && ic->op != '=')
1096 positionRegs(OP_SYMBOL(IC_RESULT(ic)),
1097 OP_SYMBOL(IC_LEFT(ic)),ic->lineno);
1098 /* do the same for the right operand */
1099 if (IC_RIGHT(ic) && IS_SYMOP(IC_RIGHT(ic)) &&
1100 OP_SYMBOL(IC_RIGHT(ic))->nRegs && ic->op != '=')
1101 positionRegs(OP_SYMBOL(IC_RESULT(ic)),
1102 OP_SYMBOL(IC_RIGHT(ic)),ic->lineno);
1114 /*-----------------------------------------------------------------*/
1115 /* rUmaskForOp :- returns register mask for an operand */
1116 /*-----------------------------------------------------------------*/
1117 static bitVect *rUmaskForOp (operand *op)
1123 /* only temporaries are assigned registers */
1127 sym = OP_SYMBOL(op);
1129 /* if spilt or no registers assigned to it
1131 if (sym->isspilt || !sym->nRegs)
1134 rumask = newBitVect(mcs51_nRegs);
1136 for (j = 0; j < sym->nRegs; j++) {
1137 rumask = bitVectSetBit(rumask,
1138 sym->regs[j]->rIdx);
1144 /*-----------------------------------------------------------------*/
1145 /* regsUsedIniCode :- returns bit vector of registers used in iCode*/
1146 /*-----------------------------------------------------------------*/
1147 static bitVect *regsUsedIniCode (iCode *ic)
1149 bitVect *rmask = newBitVect(mcs51_nRegs);
1151 /* do the special cases first */
1152 if (ic->op == IFX ) {
1153 rmask = bitVectUnion(rmask,
1154 rUmaskForOp(IC_COND(ic)));
1158 /* for the jumptable */
1159 if (ic->op == JUMPTABLE) {
1160 rmask = bitVectUnion(rmask,
1161 rUmaskForOp(IC_JTCOND(ic)));
1166 /* of all other cases */
1168 rmask = bitVectUnion(rmask,
1169 rUmaskForOp(IC_LEFT(ic)));
1173 rmask = bitVectUnion(rmask,
1174 rUmaskForOp(IC_RIGHT(ic)));
1177 rmask = bitVectUnion(rmask,
1178 rUmaskForOp(IC_RESULT(ic)));
1184 /*-----------------------------------------------------------------*/
1185 /* createRegMask - for each instruction will determine the regsUsed*/
1186 /*-----------------------------------------------------------------*/
1187 static void createRegMask (eBBlock **ebbs, int count)
1191 /* for all blocks */
1192 for (i = 0; i < count ; i++ ) {
1195 if ( ebbs[i]->noPath &&
1196 ( ebbs[i]->entryLabel != entryLabel &&
1197 ebbs[i]->entryLabel != returnLabel ))
1200 /* for all instructions */
1201 for ( ic = ebbs[i]->sch ; ic ; ic = ic->next ) {
1205 if (SKIP_IC2(ic) || !ic->rlive)
1208 /* first mark the registers used in this
1210 ic->rUsed = regsUsedIniCode(ic);
1211 _G.funcrUsed = bitVectUnion(_G.funcrUsed,ic->rUsed);
1213 /* now create the register mask for those
1214 registers that are in use : this is a
1215 super set of ic->rUsed */
1216 ic->rMask = newBitVect(mcs51_nRegs+1);
1218 /* for all live Ranges alive at this point */
1219 for (j = 1; j < ic->rlive->size; j++ ) {
1223 /* if not alive then continue */
1224 if (!bitVectBitValue(ic->rlive,j))
1227 /* find the live range we are interested in */
1228 if (!(sym = hTabItemWithKey(liveRanges,j))) {
1229 werror (E_INTERNAL_ERROR,__FILE__,__LINE__,
1230 "createRegMask cannot find live range");
1234 /* if no register assigned to it */
1235 if (!sym->nRegs || sym->isspilt)
1238 /* for all the registers allocated to it */
1239 for (k = 0 ; k < sym->nRegs ;k++)
1242 bitVectSetBit(ic->rMask,sym->regs[k]->rIdx);
1248 /*-----------------------------------------------------------------*/
1249 /* rematStr - returns the rematerialized string for a remat var */
1250 /*-----------------------------------------------------------------*/
1251 static char *rematStr (symbol *sym)
1254 iCode *ic = sym->rematiCode;
1258 /* if plus or minus print the right hand side */
1259 if (ic->op == '+' || ic->op == '-') {
1260 sprintf(s,"0x%04x %c ",(int) operandLitValue(IC_RIGHT(ic)),
1263 ic = OP_SYMBOL(IC_LEFT(ic))->rematiCode;
1267 /* we reached the end */
1268 sprintf(s,"%s",OP_SYMBOL(IC_LEFT(ic))->rname);
1275 /*-----------------------------------------------------------------*/
1276 /* regTypeNum - computes the type & number of registers required */
1277 /*-----------------------------------------------------------------*/
1278 static void regTypeNum ()
1284 /* for each live range do */
1285 for ( sym = hTabFirstItem(liveRanges,&k); sym ;
1286 sym = hTabNextItem(liveRanges,&k)) {
1288 /* if used zero times then no registers needed */
1289 if ((sym->liveTo - sym->liveFrom) == 0)
1293 /* if the live range is a temporary */
1296 /* if the type is marked as a conditional */
1297 if (sym->regType == REG_CND)
1300 /* if used in return only then we don't
1302 if (sym->ruonly || sym->accuse) {
1303 if (IS_AGGREGATE(sym->type) || sym->isptr)
1304 sym->type = aggrToPtr(sym->type,FALSE);
1308 /* if the symbol has only one definition &
1309 that definition is a get_pointer and the
1310 pointer we are getting is rematerializable and
1313 if (bitVectnBitsOn(sym->defs) == 1 &&
1314 (ic = hTabItemWithKey(iCodehTab,
1315 bitVectFirstBit(sym->defs))) &&
1317 !IS_BITVAR(sym->etype)) {
1320 /* if remat in data space */
1321 if (OP_SYMBOL(IC_LEFT(ic))->remat &&
1322 DCL_TYPE(aggrToPtr(sym->type,FALSE)) == POINTER) {
1324 /* create a psuedo symbol & force a spil */
1325 symbol *psym = newSymbol(rematStr(OP_SYMBOL(IC_LEFT(ic))),1);
1326 psym->type = sym->type;
1327 psym->etype = sym->etype;
1328 strcpy(psym->rname,psym->name);
1330 sym->usl.spillLoc = psym;
1334 /* if in data space or idata space then try to
1335 allocate pointer register */
1339 /* if not then we require registers */
1340 sym->nRegs = ((IS_AGGREGATE(sym->type) || sym->isptr ) ?
1341 getSize(sym->type = aggrToPtr(sym->type,FALSE)) :
1342 getSize(sym->type));
1344 if (sym->nRegs > 4) {
1345 fprintf(stderr,"allocated more than 4 or 0 registers for type ");
1346 printTypeChain(sym->type,stderr);fprintf(stderr,"\n");
1349 /* determine the type of register required */
1350 if (sym->nRegs == 1 &&
1351 IS_PTR(sym->type) &&
1353 sym->regType = REG_PTR ;
1355 sym->regType = REG_GPR ;
1358 /* for the first run we don't provide */
1359 /* registers for true symbols we will */
1360 /* see how things go */
1366 /*-----------------------------------------------------------------*/
1367 /* freeAllRegs - mark all registers as free */
1368 /*-----------------------------------------------------------------*/
1369 static void freeAllRegs()
1373 for (i=0;i< mcs51_nRegs;i++ )
1374 regs8051[i].isFree = 1;
1377 /*-----------------------------------------------------------------*/
1378 /* deallocStackSpil - this will set the stack pointer back */
1379 /*-----------------------------------------------------------------*/
1380 static DEFSETFUNC(deallocStackSpil)
1388 /*-----------------------------------------------------------------*/
1389 /* farSpacePackable - returns the packable icode for far variables */
1390 /*-----------------------------------------------------------------*/
1391 static iCode *farSpacePackable (iCode *ic)
1395 /* go thru till we find a definition for the
1396 symbol on the right */
1397 for ( dic = ic->prev ; dic ; dic = dic->prev) {
1399 /* if the definition is a call then no */
1400 if ((dic->op == CALL || dic->op == PCALL) &&
1401 IC_RESULT(dic)->key == IC_RIGHT(ic)->key) {
1405 /* if shift by unknown amount then not */
1406 if ((dic->op == LEFT_OP || dic->op == RIGHT_OP) &&
1407 IC_RESULT(dic)->key == IC_RIGHT(ic)->key)
1410 /* if pointer get and size > 1 */
1411 if (POINTER_GET(dic) &&
1412 getSize(aggrToPtr(operandType(IC_LEFT(dic)),FALSE)) > 1)
1415 if (POINTER_SET(dic) &&
1416 getSize(aggrToPtr(operandType(IC_RESULT(dic)),FALSE)) > 1)
1419 /* if any three is a true symbol in far space */
1420 if (IC_RESULT(dic) &&
1421 IS_TRUE_SYMOP(IC_RESULT(dic)) &&
1422 isOperandInFarSpace(IC_RESULT(dic)))
1425 if (IC_RIGHT(dic) &&
1426 IS_TRUE_SYMOP(IC_RIGHT(dic)) &&
1427 isOperandInFarSpace(IC_RIGHT(dic)) &&
1428 !isOperandEqual(IC_RIGHT(dic),IC_RESULT(ic)))
1432 IS_TRUE_SYMOP(IC_LEFT(dic)) &&
1433 isOperandInFarSpace(IC_LEFT(dic)) &&
1434 !isOperandEqual(IC_LEFT(dic),IC_RESULT(ic)))
1437 if (isOperandEqual(IC_RIGHT(ic),IC_RESULT(dic))) {
1438 if ( (dic->op == LEFT_OP ||
1439 dic->op == RIGHT_OP ||
1441 IS_OP_LITERAL(IC_RIGHT(dic)))
1451 /*-----------------------------------------------------------------*/
1452 /* packRegsForAssign - register reduction for assignment */
1453 /*-----------------------------------------------------------------*/
1454 static int packRegsForAssign (iCode *ic,eBBlock *ebp)
1459 /* !IS_TRUE_SYMOP(IC_RESULT(ic)) || */
1460 !IS_ITEMP(IC_RIGHT(ic)) ||
1461 OP_LIVETO(IC_RIGHT(ic)) > ic->seq ||
1462 OP_SYMBOL(IC_RIGHT(ic))->isind)
1465 /* if the true symbol is defined in far space or on stack
1466 then we should not since this will increase register pressure */
1467 if (isOperandInFarSpace(IC_RESULT(ic))) {
1468 if ((dic = farSpacePackable(ic)))
1474 /* find the definition of iTempNN scanning backwards if we find a
1475 a use of the true symbol in before we find the definition then
1477 for ( dic = ic->prev ; dic ; dic = dic->prev) {
1479 /* if there is a function call and this is
1480 a parameter & not my parameter then don't pack it */
1481 if ( (dic->op == CALL || dic->op == PCALL) &&
1482 (OP_SYMBOL(IC_RESULT(ic))->_isparm &&
1483 !OP_SYMBOL(IC_RESULT(ic))->ismyparm)) {
1491 if (IS_TRUE_SYMOP(IC_RESULT(dic)) &&
1492 IS_OP_VOLATILE(IC_RESULT(dic))) {
1497 if (IS_SYMOP(IC_RESULT(dic)) &&
1498 IC_RESULT(dic)->key == IC_RIGHT(ic)->key) {
1499 if (POINTER_SET(dic))
1505 if (IS_SYMOP(IC_RIGHT(dic)) &&
1506 (IC_RIGHT(dic)->key == IC_RESULT(ic)->key ||
1507 IC_RIGHT(dic)->key == IC_RIGHT(ic)->key)) {
1512 if (IS_SYMOP(IC_LEFT(dic)) &&
1513 (IC_LEFT(dic)->key == IC_RESULT(ic)->key ||
1514 IC_LEFT(dic)->key == IC_RIGHT(ic)->key)) {
1519 if (POINTER_SET(dic) &&
1520 IC_RESULT(dic)->key == IC_RESULT(ic)->key ) {
1527 return 0 ; /* did not find */
1529 /* if the result is on stack or iaccess then it must be
1530 the same atleast one of the operands */
1531 if (OP_SYMBOL(IC_RESULT(ic))->onStack ||
1532 OP_SYMBOL(IC_RESULT(ic))->iaccess ) {
1534 /* the operation has only one symbol
1535 operator then we can pack */
1536 if ((IC_LEFT(dic) && !IS_SYMOP(IC_LEFT(dic))) ||
1537 (IC_RIGHT(dic) && !IS_SYMOP(IC_RIGHT(dic))))
1540 if (!((IC_LEFT(dic) &&
1541 IC_RESULT(ic)->key == IC_LEFT(dic)->key) ||
1543 IC_RESULT(ic)->key == IC_RIGHT(dic)->key)))
1547 /* found the definition */
1548 /* replace the result with the result of */
1549 /* this assignment and remove this assignment */
1550 IC_RESULT(dic) = IC_RESULT(ic) ;
1552 if (IS_ITEMP(IC_RESULT(dic)) && OP_SYMBOL(IC_RESULT(dic))->liveFrom > dic->seq) {
1553 OP_SYMBOL(IC_RESULT(dic))->liveFrom = dic->seq;
1555 /* delete from liverange table also
1556 delete from all the points inbetween and the new
1558 for ( sic = dic; sic != ic ; sic = sic->next ) {
1559 bitVectUnSetBit(sic->rlive,IC_RESULT(ic)->key);
1560 if (IS_ITEMP(IC_RESULT(dic)))
1561 bitVectSetBit(sic->rlive,IC_RESULT(dic)->key);
1564 remiCodeFromeBBlock(ebp,ic);
1565 hTabDeleteItem (&iCodehTab,ic->key,ic,DELETE_ITEM,NULL);
1570 /*-----------------------------------------------------------------*/
1571 /* findAssignToSym : scanning backwards looks for first assig found*/
1572 /*-----------------------------------------------------------------*/
1573 static iCode *findAssignToSym (operand *op,iCode *ic)
1577 for (dic = ic->prev ; dic ; dic = dic->prev) {
1579 /* if definition by assignment */
1580 if (dic->op == '=' &&
1581 !POINTER_SET(dic) &&
1582 IC_RESULT(dic)->key == op->key
1583 /* && IS_TRUE_SYMOP(IC_RIGHT(dic)) */
1586 /* we are interested only if defined in far space */
1587 /* or in stack space in case of + & - */
1589 /* if assigned to a non-symbol then return
1591 if (!IS_SYMOP(IC_RIGHT(dic)))
1594 /* if the symbol is in far space then
1596 if (isOperandInFarSpace(IC_RIGHT(dic)))
1599 /* for + & - operations make sure that
1600 if it is on the stack it is the same
1601 as one of the three operands */
1602 if ((ic->op == '+' || ic->op == '-') &&
1603 OP_SYMBOL(IC_RIGHT(dic))->onStack) {
1605 if ( IC_RESULT(ic)->key != IC_RIGHT(dic)->key &&
1606 IC_LEFT(ic)->key != IC_RIGHT(dic)->key &&
1607 IC_RIGHT(ic)->key != IC_RIGHT(dic)->key)
1615 /* if we find an usage then we cannot delete it */
1616 if (IC_LEFT(dic) && IC_LEFT(dic)->key == op->key)
1619 if (IC_RIGHT(dic) && IC_RIGHT(dic)->key == op->key)
1622 if (POINTER_SET(dic) && IC_RESULT(dic)->key == op->key)
1626 /* now make sure that the right side of dic
1627 is not defined between ic & dic */
1629 iCode *sic = dic->next ;
1631 for (; sic != ic ; sic = sic->next)
1632 if (IC_RESULT(sic) &&
1633 IC_RESULT(sic)->key == IC_RIGHT(dic)->key)
1642 /*-----------------------------------------------------------------*/
1643 /* packRegsForSupport :- reduce some registers for support calls */
1644 /*-----------------------------------------------------------------*/
1645 static int packRegsForSupport (iCode *ic, eBBlock *ebp)
1648 /* for the left & right operand :- look to see if the
1649 left was assigned a true symbol in far space in that
1650 case replace them */
1651 if (IS_ITEMP(IC_LEFT(ic)) &&
1652 OP_SYMBOL(IC_LEFT(ic))->liveTo <= ic->seq) {
1653 iCode *dic = findAssignToSym(IC_LEFT(ic),ic);
1659 /* found it we need to remove it from the
1661 for ( sic = dic; sic != ic ; sic = sic->next )
1662 bitVectUnSetBit(sic->rlive,IC_LEFT(ic)->key);
1664 IC_LEFT(ic)->operand.symOperand =
1665 IC_RIGHT(dic)->operand.symOperand;
1666 IC_LEFT(ic)->key = IC_RIGHT(dic)->operand.symOperand->key;
1667 remiCodeFromeBBlock(ebp,dic);
1668 hTabDeleteItem (&iCodehTab,dic->key,dic,DELETE_ITEM,NULL);
1672 /* do the same for the right operand */
1675 IS_ITEMP(IC_RIGHT(ic)) &&
1676 OP_SYMBOL(IC_RIGHT(ic))->liveTo <= ic->seq) {
1677 iCode *dic = findAssignToSym(IC_RIGHT(ic),ic);
1683 /* if this is a subtraction & the result
1684 is a true symbol in far space then don't pack */
1685 if (ic->op == '-' && IS_TRUE_SYMOP(IC_RESULT(dic))) {
1686 link *etype =getSpec(operandType(IC_RESULT(dic)));
1687 if (IN_FARSPACE(SPEC_OCLS(etype)))
1690 /* found it we need to remove it from the
1692 for ( sic = dic; sic != ic ; sic = sic->next )
1693 bitVectUnSetBit(sic->rlive,IC_RIGHT(ic)->key);
1695 IC_RIGHT(ic)->operand.symOperand =
1696 IC_RIGHT(dic)->operand.symOperand;
1697 IC_RIGHT(ic)->key = IC_RIGHT(dic)->operand.symOperand->key;
1699 remiCodeFromeBBlock(ebp,dic);
1700 hTabDeleteItem (&iCodehTab,dic->key,dic,DELETE_ITEM,NULL);
1707 #define IS_OP_RUONLY(x) (x && IS_SYMOP(x) && OP_SYMBOL(x)->ruonly)
1710 /*-----------------------------------------------------------------*/
1711 /* packRegsForOneuse : - will reduce some registers for single Use */
1712 /*-----------------------------------------------------------------*/
1713 static iCode *packRegsForOneuse (iCode *ic, operand *op , eBBlock *ebp)
1718 /* if returning a literal then do nothing */
1722 /* only upto 2 bytes since we cannot predict
1723 the usage of b, & acc */
1724 if (getSize(operandType(op)) > (fReturnSize - 2) &&
1729 /* this routine will mark the a symbol as used in one
1730 instruction use only && if the defintion is local
1731 (ie. within the basic block) && has only one definition &&
1732 that definiion is either a return value from a
1733 function or does not contain any variables in
1735 uses = bitVectCopy(OP_USES(op));
1736 bitVectUnSetBit(uses,ic->key); /* take away this iCode */
1737 if (!bitVectIsZero(uses)) /* has other uses */
1740 /* if it has only one defintion */
1741 if (bitVectnBitsOn(OP_DEFS(op)) > 1)
1742 return NULL ; /* has more than one definition */
1744 /* get the that definition */
1746 hTabItemWithKey(iCodehTab,
1747 bitVectFirstBit(OP_DEFS(op)))))
1750 /* found the definition now check if it is local */
1751 if (dic->seq < ebp->fSeq ||
1752 dic->seq > ebp->lSeq)
1753 return NULL ; /* non-local */
1755 /* now check if it is the return from
1757 if (dic->op == CALL || dic->op == PCALL ) {
1758 if (ic->op != SEND && ic->op != RETURN) {
1759 OP_SYMBOL(op)->ruonly = 1;
1766 /* otherwise check that the definition does
1767 not contain any symbols in far space */
1768 if (isOperandInFarSpace(IC_LEFT(dic)) ||
1769 isOperandInFarSpace(IC_RIGHT(dic)) ||
1770 IS_OP_RUONLY(IC_LEFT(ic)) ||
1771 IS_OP_RUONLY(IC_RIGHT(ic)) ) {
1775 /* if pointer set then make sure the pointer
1777 if (POINTER_SET(dic) &&
1778 !IS_DATA_PTR(aggrToPtr(operandType(IC_RESULT(dic)),FALSE)))
1781 if (POINTER_GET(dic) &&
1782 !IS_DATA_PTR(aggrToPtr(operandType(IC_LEFT(dic)),FALSE)))
1787 /* also make sure the intervenening instructions
1788 don't have any thing in far space */
1789 for (dic = dic->next ; dic && dic != ic ; dic = dic->next) {
1791 /* if there is an intervening function call then no */
1792 if (dic->op == CALL || dic->op == PCALL)
1794 /* if pointer set then make sure the pointer
1796 if (POINTER_SET(dic) &&
1797 !IS_DATA_PTR(aggrToPtr(operandType(IC_RESULT(dic)),FALSE)))
1800 if (POINTER_GET(dic) &&
1801 !IS_DATA_PTR(aggrToPtr(operandType(IC_LEFT(dic)),FALSE)))
1804 /* if address of & the result is remat the okay */
1805 if (dic->op == ADDRESS_OF &&
1806 OP_SYMBOL(IC_RESULT(dic))->remat)
1809 /* if operand has size of three or more & this
1810 operation is a '*','/' or '%' then 'b' may
1812 if (( dic->op == '%' || dic->op == '/' || dic->op == '*') &&
1813 getSize(operandType(op)) >= 3)
1816 /* if left or right or result is in far space */
1817 if (isOperandInFarSpace(IC_LEFT(dic)) ||
1818 isOperandInFarSpace(IC_RIGHT(dic)) ||
1819 isOperandInFarSpace(IC_RESULT(dic)) ||
1820 IS_OP_RUONLY(IC_LEFT(dic)) ||
1821 IS_OP_RUONLY(IC_RIGHT(dic)) ||
1822 IS_OP_RUONLY(IC_RESULT(dic)) ) {
1827 OP_SYMBOL(op)->ruonly = 1;
1832 /*-----------------------------------------------------------------*/
1833 /* isBitwiseOptimizable - requirements of JEAN LOUIS VERN */
1834 /*-----------------------------------------------------------------*/
1835 static bool isBitwiseOptimizable (iCode *ic)
1837 link *ltype = getSpec(operandType(IC_LEFT(ic)));
1838 link *rtype = getSpec(operandType(IC_RIGHT(ic)));
1840 /* bitwise operations are considered optimizable
1841 under the following conditions (Jean-Louis VERN)
1853 if ( IS_LITERAL(rtype) ||
1854 (IS_BITVAR(ltype) && IN_BITSPACE(SPEC_OCLS(ltype))))
1860 /*-----------------------------------------------------------------*/
1861 /* packRegsForAccUse - pack registers for acc use */
1862 /*-----------------------------------------------------------------*/
1863 static void packRegsForAccUse (iCode *ic)
1867 /* if + or - then it has to be one byte result */
1868 if ((ic->op == '+' || ic->op == '-')
1869 && getSize(operandType(IC_RESULT(ic))) > 1)
1872 /* if shift operation make sure right side is not a literal */
1873 if (ic->op == RIGHT_OP &&
1874 ( isOperandLiteral(IC_RIGHT(ic)) ||
1875 getSize(operandType(IC_RESULT(ic))) > 1))
1878 if (ic->op == LEFT_OP &&
1879 ( isOperandLiteral(IC_RIGHT(ic)) ||
1880 getSize(operandType(IC_RESULT(ic))) > 1))
1884 /* has only one definition */
1885 if (bitVectnBitsOn(OP_DEFS(IC_RESULT(ic))) > 1)
1888 /* has only one use */
1889 if (bitVectnBitsOn(OP_USES(IC_RESULT(ic))) > 1)
1892 /* and the usage immediately follows this iCode */
1893 if (!(uic = hTabItemWithKey(iCodehTab,
1894 bitVectFirstBit(OP_USES(IC_RESULT(ic))))))
1897 if (ic->next != uic)
1900 /* if it is a conditional branch then we definitely can */
1901 if (uic->op == IFX )
1904 if ( uic->op == JUMPTABLE )
1907 /* if the usage is not is an assignment
1908 or an arithmetic / bitwise / shift operation then not */
1909 if (POINTER_SET(uic) &&
1910 getSize(aggrToPtr(operandType(IC_RESULT(uic)),FALSE)) > 1)
1913 if (uic->op != '=' &&
1914 !IS_ARITHMETIC_OP(uic) &&
1915 !IS_BITWISE_OP(uic) &&
1916 uic->op != LEFT_OP &&
1917 uic->op != RIGHT_OP )
1920 /* if used in ^ operation then make sure right is not a
1922 if (uic->op == '^' && isOperandLiteral(IC_RIGHT(uic)))
1925 /* if shift operation make sure right side is not a literal */
1926 if (uic->op == RIGHT_OP &&
1927 ( isOperandLiteral(IC_RIGHT(uic)) ||
1928 getSize(operandType(IC_RESULT(uic))) > 1))
1931 if (uic->op == LEFT_OP &&
1932 ( isOperandLiteral(IC_RIGHT(uic)) ||
1933 getSize(operandType(IC_RESULT(uic))) > 1))
1936 /* make sure that the result of this icode is not on the
1937 stack, since acc is used to compute stack offset */
1938 if (IS_TRUE_SYMOP(IC_RESULT(uic)) &&
1939 OP_SYMBOL(IC_RESULT(uic))->onStack)
1942 /* if either one of them in far space then we cannot */
1943 if ((IS_TRUE_SYMOP(IC_LEFT(uic)) &&
1944 isOperandInFarSpace(IC_LEFT(uic))) ||
1945 (IS_TRUE_SYMOP(IC_RIGHT(uic)) &&
1946 isOperandInFarSpace(IC_RIGHT(uic))))
1949 /* if the usage has only one operand then we can */
1950 if (IC_LEFT(uic) == NULL ||
1951 IC_RIGHT(uic) == NULL)
1954 /* make sure this is on the left side if not
1955 a '+' since '+' is commutative */
1956 if (ic->op != '+' &&
1957 IC_LEFT(uic)->key != IC_RESULT(ic)->key)
1960 /* if one of them is a literal then we can */
1961 if ((IC_LEFT(uic) && IS_OP_LITERAL(IC_LEFT(uic))) ||
1962 (IC_RIGHT(uic) && IS_OP_LITERAL(IC_RIGHT(uic)))) {
1963 OP_SYMBOL(IC_RESULT(ic))->accuse = 1;
1967 /* if the other one is not on stack then we can */
1968 if (IC_LEFT(uic)->key == IC_RESULT(ic)->key &&
1969 (IS_ITEMP(IC_RIGHT(uic)) ||
1970 (IS_TRUE_SYMOP(IC_RIGHT(uic)) &&
1971 !OP_SYMBOL(IC_RIGHT(uic))->onStack)))
1974 if (IC_RIGHT(uic)->key == IC_RESULT(ic)->key &&
1975 (IS_ITEMP(IC_LEFT(uic)) ||
1976 (IS_TRUE_SYMOP(IC_LEFT(uic)) &&
1977 !OP_SYMBOL(IC_LEFT(uic))->onStack)))
1983 OP_SYMBOL(IC_RESULT(ic))->accuse = 1;
1988 /*-----------------------------------------------------------------*/
1989 /* packForPush - hueristics to reduce iCode for pushing */
1990 /*-----------------------------------------------------------------*/
1991 static void packForPush(iCode *ic, eBBlock *ebp)
1995 if (ic->op != IPUSH || !IS_ITEMP(IC_LEFT(ic)))
1998 /* must have only definition & one usage */
1999 if (bitVectnBitsOn(OP_DEFS(IC_LEFT(ic))) != 1 ||
2000 bitVectnBitsOn(OP_USES(IC_LEFT(ic))) != 1 )
2003 /* find the definition */
2004 if (!(dic = hTabItemWithKey(iCodehTab,
2005 bitVectFirstBit(OP_DEFS(IC_LEFT(ic))))))
2008 if (dic->op != '=' || POINTER_SET(dic))
2011 /* we now we know that it has one & only one def & use
2012 and the that the definition is an assignment */
2013 IC_LEFT(ic) = IC_RIGHT(dic);
2015 remiCodeFromeBBlock(ebp,dic);
2016 hTabDeleteItem (&iCodehTab,dic->key,dic,DELETE_ITEM,NULL);
2019 /*-----------------------------------------------------------------*/
2020 /* packRegisters - does some transformations to reduce register */
2022 /*-----------------------------------------------------------------*/
2023 static void packRegisters (eBBlock *ebp)
2032 /* look for assignments of the form */
2033 /* iTempNN = TRueSym (someoperation) SomeOperand */
2035 /* TrueSym := iTempNN:1 */
2036 for ( ic = ebp->sch ; ic ; ic = ic->next ) {
2039 /* find assignment of the form TrueSym := iTempNN:1 */
2040 if (ic->op == '=' && !POINTER_SET(ic))
2041 change += packRegsForAssign(ic,ebp);
2048 for ( ic = ebp->sch ; ic ; ic = ic->next ) {
2050 /* if this is an itemp & result of a address of a true sym
2051 then mark this as rematerialisable */
2052 if (ic->op == ADDRESS_OF &&
2053 IS_ITEMP(IC_RESULT(ic)) &&
2054 IS_TRUE_SYMOP(IC_LEFT(ic)) &&
2055 bitVectnBitsOn(OP_DEFS(IC_RESULT(ic))) == 1 &&
2056 !OP_SYMBOL(IC_LEFT(ic))->onStack ) {
2058 OP_SYMBOL(IC_RESULT(ic))->remat = 1;
2059 OP_SYMBOL(IC_RESULT(ic))->rematiCode = ic;
2060 OP_SYMBOL(IC_RESULT(ic))->usl.spillLoc = NULL;
2064 /* if straight assignment then carry remat flag if
2065 this is the only definition */
2066 if (ic->op == '=' &&
2068 IS_SYMOP(IC_RIGHT(ic)) &&
2069 OP_SYMBOL(IC_RIGHT(ic))->remat &&
2070 bitVectnBitsOn(OP_SYMBOL(IC_RESULT(ic))->defs) <= 1) {
2072 OP_SYMBOL(IC_RESULT(ic))->remat =
2073 OP_SYMBOL(IC_RIGHT(ic))->remat;
2074 OP_SYMBOL(IC_RESULT(ic))->rematiCode =
2075 OP_SYMBOL(IC_RIGHT(ic))->rematiCode ;
2078 /* if this is a +/- operation with a rematerizable
2079 then mark this as rematerializable as well only
2080 if the literal value is within the range -255 and + 255
2081 the assembler cannot handle it other wise */
2082 if ((ic->op == '+' || ic->op == '-') &&
2084 (IS_SYMOP(IC_LEFT(ic)) &&
2085 IS_ITEMP(IC_RESULT(ic)) &&
2086 OP_SYMBOL(IC_LEFT(ic))->remat &&
2087 bitVectnBitsOn(OP_DEFS(IC_RESULT(ic))) == 1 &&
2088 IS_OP_LITERAL(IC_RIGHT(ic))) ) {
2090 int i = operandLitValue(IC_RIGHT(ic));
2091 if ( i < 255 && i > -255) {
2092 OP_SYMBOL(IC_RESULT(ic))->remat = 1;
2093 OP_SYMBOL(IC_RESULT(ic))->rematiCode = ic;
2094 OP_SYMBOL(IC_RESULT(ic))->usl.spillLoc = NULL;
2098 /* mark the pointer usages */
2099 if (POINTER_SET(ic))
2100 OP_SYMBOL(IC_RESULT(ic))->uptr = 1;
2102 if (POINTER_GET(ic))
2103 OP_SYMBOL(IC_LEFT(ic))->uptr = 1;
2105 if (!SKIP_IC2(ic)) {
2106 /* if we are using a symbol on the stack
2107 then we should say mcs51_ptrRegReq */
2108 if (ic->op == IFX && IS_SYMOP(IC_COND(ic)))
2109 mcs51_ptrRegReq += ((OP_SYMBOL(IC_COND(ic))->onStack ||
2110 OP_SYMBOL(IC_COND(ic))->iaccess) ? 1 : 0);
2112 if (ic->op == JUMPTABLE && IS_SYMOP(IC_JTCOND(ic)))
2113 mcs51_ptrRegReq += ((OP_SYMBOL(IC_JTCOND(ic))->onStack ||
2114 OP_SYMBOL(IC_JTCOND(ic))->iaccess) ? 1 : 0);
2116 if (IS_SYMOP(IC_LEFT(ic)))
2117 mcs51_ptrRegReq += ((OP_SYMBOL(IC_LEFT(ic))->onStack ||
2118 OP_SYMBOL(IC_LEFT(ic))->iaccess) ? 1 : 0);
2119 if (IS_SYMOP(IC_RIGHT(ic)))
2120 mcs51_ptrRegReq += ((OP_SYMBOL(IC_RIGHT(ic))->onStack ||
2121 OP_SYMBOL(IC_RIGHT(ic))->iaccess) ? 1 : 0);
2122 if (IS_SYMOP(IC_RESULT(ic)))
2123 mcs51_ptrRegReq += ((OP_SYMBOL(IC_RESULT(ic))->onStack ||
2124 OP_SYMBOL(IC_RESULT(ic))->iaccess) ? 1 : 0);
2128 /* if the condition of an if instruction
2129 is defined in the previous instruction then
2130 mark the itemp as a conditional */
2131 if ((IS_CONDITIONAL(ic) ||
2132 ( ( ic->op == BITWISEAND ||
2135 isBitwiseOptimizable(ic))) &&
2136 ic->next && ic->next->op == IFX &&
2137 isOperandEqual(IC_RESULT(ic),IC_COND(ic->next)) &&
2138 OP_SYMBOL(IC_RESULT(ic))->liveTo <= ic->next->seq) {
2140 OP_SYMBOL(IC_RESULT(ic))->regType = REG_CND;
2144 /* reduce for support function calls */
2145 if (ic->supportRtn || ic->op == '+' || ic->op == '-' )
2146 packRegsForSupport (ic,ebp);
2148 /* some cases the redundant moves can
2149 can be eliminated for return statements */
2150 if ((ic->op == RETURN || ic->op == SEND) &&
2151 !isOperandInFarSpace(IC_LEFT(ic)) &&
2153 packRegsForOneuse (ic,IC_LEFT(ic),ebp);
2155 /* if pointer set & left has a size more than
2156 one and right is not in far space */
2157 if (POINTER_SET(ic) &&
2158 !isOperandInFarSpace(IC_RIGHT(ic)) &&
2159 !OP_SYMBOL(IC_RESULT(ic))->remat &&
2160 !IS_OP_RUONLY(IC_RIGHT(ic)) &&
2161 getSize(aggrToPtr(operandType(IC_RESULT(ic)),FALSE)) > 1 )
2163 packRegsForOneuse (ic,IC_RESULT(ic),ebp);
2165 /* if pointer get */
2166 if (POINTER_GET(ic) &&
2167 !isOperandInFarSpace(IC_RESULT(ic))&&
2168 !OP_SYMBOL(IC_LEFT(ic))->remat &&
2169 !IS_OP_RUONLY(IC_RESULT(ic)) &&
2170 getSize(aggrToPtr(operandType(IC_LEFT(ic)),FALSE)) > 1 )
2172 packRegsForOneuse (ic,IC_LEFT(ic),ebp);
2175 /* if this is cast for intergral promotion then
2176 check if only use of the definition of the
2177 operand being casted/ if yes then replace
2178 the result of that arithmetic operation with
2179 this result and get rid of the cast */
2180 if (ic->op == CAST) {
2181 link *fromType = operandType(IC_RIGHT(ic));
2182 link *toType = operandType(IC_LEFT(ic));
2184 if (IS_INTEGRAL(fromType) && IS_INTEGRAL(toType) &&
2185 getSize(fromType) != getSize(toType) ) {
2187 iCode *dic = packRegsForOneuse(ic,IC_RIGHT(ic),ebp);
2189 if (IS_ARITHMETIC_OP(dic)) {
2190 IC_RESULT(dic) = IC_RESULT(ic);
2191 remiCodeFromeBBlock(ebp,ic);
2192 hTabDeleteItem (&iCodehTab,ic->key,ic,DELETE_ITEM,NULL);
2195 OP_SYMBOL(IC_RIGHT(ic))->ruonly = 0;
2199 /* if the type from and type to are the same
2200 then if this is the only use then packit */
2201 if (checkType(operandType(IC_RIGHT(ic)),
2202 operandType(IC_LEFT(ic))) == 1) {
2203 iCode *dic = packRegsForOneuse (ic,IC_RIGHT(ic),ebp);
2205 IC_RESULT(dic) = IC_RESULT(ic);
2206 remiCodeFromeBBlock(ebp,ic);
2207 hTabDeleteItem (&iCodehTab,ic->key,ic,DELETE_ITEM,NULL);
2215 iTempNN := (some variable in farspace) V1
2220 if (ic->op == IPUSH ) {
2221 packForPush(ic,ebp);
2225 /* pack registers for accumulator use, when the
2226 result of an arithmetic or bit wise operation
2227 has only one use, that use is immediately following
2228 the defintion and the using iCode has only one
2229 operand or has two operands but one is literal &
2230 the result of that operation is not on stack then
2231 we can leave the result of this operation in acc:b
2233 if ((IS_ARITHMETIC_OP(ic)
2235 || IS_BITWISE_OP(ic)
2237 || ic->op == LEFT_OP || ic->op == RIGHT_OP
2240 IS_ITEMP(IC_RESULT(ic)) &&
2241 getSize(operandType(IC_RESULT(ic))) <= 2)
2243 packRegsForAccUse (ic);
2248 /*-----------------------------------------------------------------*/
2249 /* assignRegisters - assigns registers to each live range as need */
2250 /*-----------------------------------------------------------------*/
2251 void mcs51_assignRegisters (eBBlock **ebbs, int count)
2256 setToNull((void *)&_G.funcrUsed);
2257 mcs51_ptrRegReq = _G.stackExtend = _G.dataExtend = 0;
2258 /* if not register extentions then reduce number
2260 if (options.regExtend)
2265 /* change assignments this will remove some
2266 live ranges reducing some register pressure */
2267 for (i = 0 ; i < count ;i++ )
2268 packRegisters (ebbs[i]);
2270 if (options.dump_pack)
2271 dumpEbbsToFileExt(".dumppack",ebbs,count);
2273 /* first determine for each live range the number of
2274 registers & the type of registers required for each */
2277 /* and serially allocate registers */
2278 serialRegAssign(ebbs,count);
2280 /* if stack was extended then tell the user */
2281 if (_G.stackExtend) {
2282 /* werror(W_TOOMANY_SPILS,"stack", */
2283 /* _G.stackExtend,currFunc->name,""); */
2284 _G.stackExtend = 0 ;
2287 if (_G.dataExtend) {
2288 /* werror(W_TOOMANY_SPILS,"data space", */
2289 /* _G.dataExtend,currFunc->name,""); */
2293 /* after that create the register mask
2294 for each of the instruction */
2295 createRegMask (ebbs,count);
2297 /* redo that offsets for stacked automatic variables */
2298 redoStackOffsets ();
2300 if (options.dump_rassgn)
2301 dumpEbbsToFileExt(".dumprassgn",ebbs,count);
2303 /* now get back the chain */
2304 ic = iCodeLabelOptimize(iCodeFromeBBlock (ebbs,count));
2309 /* free up any _G.stackSpil locations allocated */
2310 applyToSet(_G.stackSpil,deallocStackSpil);
2312 setToNull((void **)&_G.stackSpil);
2313 setToNull((void **)&_G.spiltSet);
2314 /* mark all registers as free */