1 /*------------------------------------------------------------------------
3 SDCCralloc.c - source file for register allocation. (8051) specific
5 Written By - Sandeep Dutta . sandeep.dutta@usa.net (1998)
7 This program is free software; you can redistribute it and/or modify it
8 under the terms of the GNU General Public License as published by the
9 Free Software Foundation; either version 2, or (at your option) any
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program; if not, write to the Free Software
19 Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
21 In other words, you are welcome to use, share and improve this program.
22 You are forbidden to forbid anyone else to use, share and improve
23 what you give them. Help stamp out software-hoarding!
24 -------------------------------------------------------------------------*/
30 /*-----------------------------------------------------------------*/
31 /* At this point we start getting processor specific although */
32 /* some routines are non-processor specific & can be reused when */
33 /* targetting other processors. The decision for this will have */
34 /* to be made on a routine by routine basis */
35 /* routines used to pack registers are most definitely not reusable */
36 /* since the pack the registers depending strictly on the MCU */
37 /*-----------------------------------------------------------------*/
39 extern void gen51Code (iCode *);
49 bitVect *funcrUsed; /* registers used in a function */
55 /* Shared with gen.c */
56 int mcs51_ptrRegReq; /* one byte pointer register required */
62 {REG_GPR, R2_IDX, REG_GPR, "r2", "ar2", "0", 2, 1},
63 {REG_GPR, R3_IDX, REG_GPR, "r3", "ar3", "0", 3, 1},
64 {REG_GPR, R4_IDX, REG_GPR, "r4", "ar4", "0", 4, 1},
65 {REG_GPR, R5_IDX, REG_GPR, "r5", "ar5", "0", 5, 1},
66 {REG_GPR, R6_IDX, REG_GPR, "r6", "ar6", "0", 6, 1},
67 {REG_GPR, R7_IDX, REG_GPR, "r7", "ar7", "0", 7, 1},
68 {REG_PTR, R0_IDX, REG_PTR, "r0", "ar0", "0", 0, 1},
69 {REG_PTR, R1_IDX, REG_PTR, "r1", "ar1", "0", 1, 1},
70 {REG_GPR, X8_IDX, REG_GPR, "x8", "x8", "xreg", 0, 1},
71 {REG_GPR, X9_IDX, REG_GPR, "x9", "x9", "xreg", 1, 1},
72 {REG_GPR, X10_IDX, REG_GPR, "x10", "x10", "xreg", 2, 1},
73 {REG_GPR, X11_IDX, REG_GPR, "x11", "x11", "xreg", 3, 1},
74 {REG_GPR, X12_IDX, REG_GPR, "x12", "x12", "xreg", 4, 1},
75 {REG_CND, CND_IDX, REG_CND, "C", "C", "xreg", 0, 1},
78 static void spillThis (symbol *);
80 /*-----------------------------------------------------------------*/
81 /* allocReg - allocates register of given type */
82 /*-----------------------------------------------------------------*/
88 for (i = 0; i < mcs51_nRegs; i++)
91 /* if type is given as 0 then any
92 free register will do */
96 regs8051[i].isFree = 0;
99 bitVectSetBit (currFunc->regsUsed, i);
102 /* other wise look for specific type
104 if (regs8051[i].isFree &&
105 regs8051[i].type == type)
107 regs8051[i].isFree = 0;
110 bitVectSetBit (currFunc->regsUsed, i);
117 /*-----------------------------------------------------------------*/
118 /* mcs51_regWithIdx - returns pointer to register wit index number */
119 /*-----------------------------------------------------------------*/
121 mcs51_regWithIdx (int idx)
125 for (i = 0; i < mcs51_nRegs; i++)
126 if (regs8051[i].rIdx == idx)
129 werror (E_INTERNAL_ERROR, __FILE__, __LINE__,
130 "regWithIdx not found");
134 /*-----------------------------------------------------------------*/
135 /* freeReg - frees a register */
136 /*-----------------------------------------------------------------*/
142 werror (E_INTERNAL_ERROR, __FILE__, __LINE__,
143 "freeReg - Freeing NULL register");
151 /*-----------------------------------------------------------------*/
152 /* nFreeRegs - returns number of free registers */
153 /*-----------------------------------------------------------------*/
160 for (i = 0; i < mcs51_nRegs; i++)
161 if (regs8051[i].isFree && regs8051[i].type == type)
166 /*-----------------------------------------------------------------*/
167 /* nfreeRegsType - free registers with type */
168 /*-----------------------------------------------------------------*/
170 nfreeRegsType (int type)
175 if ((nfr = nFreeRegs (type)) == 0)
176 return nFreeRegs (REG_GPR);
179 return nFreeRegs (type);
183 /*-----------------------------------------------------------------*/
184 /* allDefsOutOfRange - all definitions are out of a range */
185 /*-----------------------------------------------------------------*/
187 allDefsOutOfRange (bitVect * defs, int fseq, int toseq)
194 for (i = 0; i < defs->size; i++)
198 if (bitVectBitValue (defs, i) &&
199 (ic = hTabItemWithKey (iCodehTab, i)) &&
200 (ic->seq >= fseq && ic->seq <= toseq))
209 /*-----------------------------------------------------------------*/
210 /* computeSpillable - given a point find the spillable live ranges */
211 /*-----------------------------------------------------------------*/
213 computeSpillable (iCode * ic)
217 /* spillable live ranges are those that are live at this
218 point . the following categories need to be subtracted
220 a) - those that are already spilt
221 b) - if being used by this one
222 c) - defined by this one */
224 spillable = bitVectCopy (ic->rlive);
226 bitVectCplAnd (spillable, _G.spiltSet); /* those already spilt */
228 bitVectCplAnd (spillable, ic->uses); /* used in this one */
229 bitVectUnSetBit (spillable, ic->defKey);
230 spillable = bitVectIntersect (spillable, _G.regAssigned);
235 /*-----------------------------------------------------------------*/
236 /* noSpilLoc - return true if a variable has no spil location */
237 /*-----------------------------------------------------------------*/
239 noSpilLoc (symbol * sym, eBBlock * ebp, iCode * ic)
241 return (sym->usl.spillLoc ? 0 : 1);
244 /*-----------------------------------------------------------------*/
245 /* hasSpilLoc - will return 1 if the symbol has spil location */
246 /*-----------------------------------------------------------------*/
248 hasSpilLoc (symbol * sym, eBBlock * ebp, iCode * ic)
250 return (sym->usl.spillLoc ? 1 : 0);
253 /*-----------------------------------------------------------------*/
254 /* directSpilLoc - will return 1 if the splilocation is in direct */
255 /*-----------------------------------------------------------------*/
257 directSpilLoc (symbol * sym, eBBlock * ebp, iCode * ic)
259 if (sym->usl.spillLoc &&
260 (IN_DIRSPACE (SPEC_OCLS (sym->usl.spillLoc->etype))))
266 /*-----------------------------------------------------------------*/
267 /* hasSpilLocnoUptr - will return 1 if the symbol has spil location */
268 /* but is not used as a pointer */
269 /*-----------------------------------------------------------------*/
271 hasSpilLocnoUptr (symbol * sym, eBBlock * ebp, iCode * ic)
273 return ((sym->usl.spillLoc && !sym->uptr) ? 1 : 0);
276 /*-----------------------------------------------------------------*/
277 /* rematable - will return 1 if the remat flag is set */
278 /*-----------------------------------------------------------------*/
280 rematable (symbol * sym, eBBlock * ebp, iCode * ic)
285 /*-----------------------------------------------------------------*/
286 /* notUsedInBlock - not used in this block */
287 /*-----------------------------------------------------------------*/
289 notUsedInBlock (symbol * sym, eBBlock * ebp, iCode * ic)
291 return (!bitVectBitsInCommon (sym->defs, ebp->usesDefs) &&
292 allDefsOutOfRange (sym->defs, ebp->fSeq, ebp->lSeq));
293 /* return (!bitVectBitsInCommon(sym->defs,ebp->usesDefs)); */
296 /*-----------------------------------------------------------------*/
297 /* notUsedInRemaining - not used or defined in remain of the block */
298 /*-----------------------------------------------------------------*/
300 notUsedInRemaining (symbol * sym, eBBlock * ebp, iCode * ic)
302 return ((usedInRemaining (operandFromSymbol (sym), ic) ? 0 : 1) &&
303 allDefsOutOfRange (sym->defs, ebp->fSeq, ebp->lSeq));
306 /*-----------------------------------------------------------------*/
307 /* allLRs - return true for all */
308 /*-----------------------------------------------------------------*/
310 allLRs (symbol * sym, eBBlock * ebp, iCode * ic)
315 /*-----------------------------------------------------------------*/
316 /* liveRangesWith - applies function to a given set of live range */
317 /*-----------------------------------------------------------------*/
319 liveRangesWith (bitVect * lrs, int (func) (symbol *, eBBlock *, iCode *),
320 eBBlock * ebp, iCode * ic)
325 if (!lrs || !lrs->size)
328 for (i = 1; i < lrs->size; i++)
331 if (!bitVectBitValue (lrs, i))
334 /* if we don't find it in the live range
335 hash table we are in serious trouble */
336 if (!(sym = hTabItemWithKey (liveRanges, i)))
338 werror (E_INTERNAL_ERROR, __FILE__, __LINE__,
339 "liveRangesWith could not find liveRange");
343 if (func (sym, ebp, ic) && bitVectBitValue (_G.regAssigned, sym->key))
344 addSetHead (&rset, sym);
351 /*-----------------------------------------------------------------*/
352 /* leastUsedLR - given a set determines which is the least used */
353 /*-----------------------------------------------------------------*/
355 leastUsedLR (set * sset)
357 symbol *sym = NULL, *lsym = NULL;
359 sym = lsym = setFirstItem (sset);
364 for (; lsym; lsym = setNextItem (sset))
367 /* if usage is the same then prefer
368 the spill the smaller of the two */
369 if (lsym->used == sym->used)
370 if (getSize (lsym->type) < getSize (sym->type))
374 if (lsym->used < sym->used)
379 setToNull ((void **) &sset);
384 /*-----------------------------------------------------------------*/
385 /* noOverLap - will iterate through the list looking for over lap */
386 /*-----------------------------------------------------------------*/
388 noOverLap (set * itmpStack, symbol * fsym)
393 for (sym = setFirstItem (itmpStack); sym;
394 sym = setNextItem (itmpStack))
396 if (sym->liveFrom < fsym->liveTo &&
397 sym->liveTo > fsym->liveTo) return 0;
399 if (sym->liveFrom < fsym->liveFrom &&
400 sym->liveTo > fsym->liveFrom) return 0;
406 /*-----------------------------------------------------------------*/
407 /* isFree - will return 1 if the a free spil location is found */
408 /*-----------------------------------------------------------------*/
413 V_ARG (symbol **, sloc);
414 V_ARG (symbol *, fsym);
416 /* if already found */
420 /* if it is free && and the itmp assigned to
421 this does not have any overlapping live ranges
422 with the one currently being assigned and
423 the size can be accomodated */
425 noOverLap (sym->usl.itmpStack, fsym) &&
426 getSize (sym->type) >= getSize (fsym->type))
435 /*-----------------------------------------------------------------*/
436 /* spillLRWithPtrReg :- will spil those live ranges which use PTR */
437 /*-----------------------------------------------------------------*/
439 spillLRWithPtrReg (symbol * forSym)
445 if (!_G.regAssigned ||
446 bitVectIsZero (_G.regAssigned))
449 r0 = mcs51_regWithIdx (R0_IDX);
450 r1 = mcs51_regWithIdx (R1_IDX);
452 /* for all live ranges */
453 for (lrsym = hTabFirstItem (liveRanges, &k); lrsym;
454 lrsym = hTabNextItem (liveRanges, &k))
458 /* if no registers assigned to it or
460 /* if it does not overlap with this then
461 not need to spill it */
463 if (lrsym->isspilt || !lrsym->nRegs ||
464 (lrsym->liveTo < forSym->liveFrom))
467 /* go thru the registers : if it is either
468 r0 or r1 then spil it */
469 for (j = 0; j < lrsym->nRegs; j++)
470 if (lrsym->regs[j] == r0 ||
471 lrsym->regs[j] == r1)
480 /*-----------------------------------------------------------------*/
481 /* createStackSpil - create a location on the stack to spil */
482 /*-----------------------------------------------------------------*/
484 createStackSpil (symbol * sym)
487 int useXstack, model;
491 /* first go try and find a free one that is already
492 existing on the stack */
493 if (applyToSet (_G.stackSpil, isFree, &sloc, sym))
495 /* found a free one : just update & return */
496 sym->usl.spillLoc = sloc;
499 addSetHead (&sloc->usl.itmpStack, sym);
503 /* could not then have to create one , this is the hard part
504 we need to allocate this on the stack : this is really a
505 hack!! but cannot think of anything better at this time */
507 if (sprintf (slocBuffer, "sloc%d", _G.slocNum++) >= sizeof (slocBuffer))
509 fprintf (stderr, "***Internal error: slocBuffer overflowed: %s:%d\n",
514 sloc = newiTemp (slocBuffer);
516 /* set the type to the spilling symbol */
517 sloc->type = copyLinkChain (sym->type);
518 sloc->etype = getSpec (sloc->type);
519 SPEC_SCLS (sloc->etype) = S_DATA;
520 SPEC_EXTR (sloc->etype) = 0;
522 /* we don't allow it to be allocated`
523 onto the external stack since : so we
524 temporarily turn it off ; we also
525 turn off memory model to prevent
526 the spil from going to the external storage
529 useXstack = options.useXstack;
530 model = options.model;
531 /* noOverlay = options.noOverlay; */
532 /* options.noOverlay = 1; */
533 options.model = options.useXstack = 0;
537 options.useXstack = useXstack;
538 options.model = model;
539 /* options.noOverlay = noOverlay; */
540 sloc->isref = 1; /* to prevent compiler warning */
542 /* if it is on the stack then update the stack */
543 if (IN_STACK (sloc->etype))
545 currFunc->stack += getSize (sloc->type);
546 _G.stackExtend += getSize (sloc->type);
549 _G.dataExtend += getSize (sloc->type);
551 /* add it to the _G.stackSpil set */
552 addSetHead (&_G.stackSpil, sloc);
553 sym->usl.spillLoc = sloc;
556 /* add it to the set of itempStack set
557 of the spill location */
558 addSetHead (&sloc->usl.itmpStack, sym);
562 /*-----------------------------------------------------------------*/
563 /* isSpiltOnStack - returns true if the spil location is on stack */
564 /*-----------------------------------------------------------------*/
566 isSpiltOnStack (symbol * sym)
576 /* if (sym->_G.stackSpil) */
579 if (!sym->usl.spillLoc)
582 etype = getSpec (sym->usl.spillLoc->type);
583 if (IN_STACK (etype))
589 /*-----------------------------------------------------------------*/
590 /* spillThis - spils a specific operand */
591 /*-----------------------------------------------------------------*/
593 spillThis (symbol * sym)
596 /* if this is rematerializable or has a spillLocation
597 we are okay, else we need to create a spillLocation
599 if (!(sym->remat || sym->usl.spillLoc))
600 createStackSpil (sym);
603 /* mark it has spilt & put it in the spilt set */
605 _G.spiltSet = bitVectSetBit (_G.spiltSet, sym->key);
607 bitVectUnSetBit (_G.regAssigned, sym->key);
609 for (i = 0; i < sym->nRegs; i++)
613 freeReg (sym->regs[i]);
617 /* if spilt on stack then free up r0 & r1
618 if they could have been assigned to some
620 if (!mcs51_ptrRegReq && isSpiltOnStack (sym))
623 spillLRWithPtrReg (sym);
626 if (sym->usl.spillLoc && !sym->remat)
627 sym->usl.spillLoc->allocreq = 1;
631 /*-----------------------------------------------------------------*/
632 /* selectSpil - select a iTemp to spil : rather a simple procedure */
633 /*-----------------------------------------------------------------*/
635 selectSpil (iCode * ic, eBBlock * ebp, symbol * forSym)
637 bitVect *lrcs = NULL;
641 /* get the spillable live ranges */
642 lrcs = computeSpillable (ic);
644 /* get all live ranges that are rematerizable */
645 if ((selectS = liveRangesWith (lrcs, rematable, ebp, ic)))
648 /* return the least used of these */
649 return leastUsedLR (selectS);
652 /* get live ranges with spillLocations in direct space */
653 if ((selectS = liveRangesWith (lrcs, directSpilLoc, ebp, ic)))
655 sym = leastUsedLR (selectS);
656 strcpy (sym->rname, (sym->usl.spillLoc->rname[0] ?
657 sym->usl.spillLoc->rname :
658 sym->usl.spillLoc->name));
660 /* mark it as allocation required */
661 sym->usl.spillLoc->allocreq = 1;
665 /* if the symbol is local to the block then */
666 if (forSym->liveTo < ebp->lSeq)
669 /* check if there are any live ranges allocated
670 to registers that are not used in this block */
671 if (!_G.blockSpil && (selectS = liveRangesWith (lrcs, notUsedInBlock, ebp, ic)))
673 sym = leastUsedLR (selectS);
674 /* if this is not rematerializable */
683 /* check if there are any live ranges that not
684 used in the remainder of the block */
685 if (!_G.blockSpil && (selectS = liveRangesWith (lrcs, notUsedInRemaining, ebp, ic)))
687 sym = leastUsedLR (selectS);
700 /* find live ranges with spillocation && not used as pointers */
701 if ((selectS = liveRangesWith (lrcs, hasSpilLocnoUptr, ebp, ic)))
704 sym = leastUsedLR (selectS);
705 /* mark this as allocation required */
706 sym->usl.spillLoc->allocreq = 1;
710 /* find live ranges with spillocation */
711 if ((selectS = liveRangesWith (lrcs, hasSpilLoc, ebp, ic)))
714 sym = leastUsedLR (selectS);
715 sym->usl.spillLoc->allocreq = 1;
719 /* couldn't find then we need to create a spil
720 location on the stack , for which one? the least
722 if ((selectS = liveRangesWith (lrcs, noSpilLoc, ebp, ic)))
725 /* return a created spil location */
726 sym = createStackSpil (leastUsedLR (selectS));
727 sym->usl.spillLoc->allocreq = 1;
731 /* this is an extreme situation we will spill
732 this one : happens very rarely but it does happen */
738 /*-----------------------------------------------------------------*/
739 /* spilSomething - spil some variable & mark registers as free */
740 /*-----------------------------------------------------------------*/
742 spilSomething (iCode * ic, eBBlock * ebp, symbol * forSym)
747 /* get something we can spil */
748 ssym = selectSpil (ic, ebp, forSym);
750 /* mark it as spilt */
752 _G.spiltSet = bitVectSetBit (_G.spiltSet, ssym->key);
754 /* mark it as not register assigned &
755 take it away from the set */
756 bitVectUnSetBit (_G.regAssigned, ssym->key);
758 /* mark the registers as free */
759 for (i = 0; i < ssym->nRegs; i++)
761 freeReg (ssym->regs[i]);
763 /* if spilt on stack then free up r0 & r1
764 if they could have been assigned to as gprs */
765 if (!mcs51_ptrRegReq && isSpiltOnStack (ssym))
768 spillLRWithPtrReg (ssym);
771 /* if this was a block level spil then insert push & pop
772 at the start & end of block respectively */
775 iCode *nic = newiCode (IPUSH, operandFromSymbol (ssym), NULL);
776 /* add push to the start of the block */
777 addiCodeToeBBlock (ebp, nic, (ebp->sch->op == LABEL ?
778 ebp->sch->next : ebp->sch));
779 nic = newiCode (IPOP, operandFromSymbol (ssym), NULL);
780 /* add pop to the end of the block */
781 addiCodeToeBBlock (ebp, nic, NULL);
784 /* if spilt because not used in the remainder of the
785 block then add a push before this instruction and
786 a pop at the end of the block */
787 if (ssym->remainSpil)
790 iCode *nic = newiCode (IPUSH, operandFromSymbol (ssym), NULL);
791 /* add push just before this instruction */
792 addiCodeToeBBlock (ebp, nic, ic);
794 nic = newiCode (IPOP, operandFromSymbol (ssym), NULL);
795 /* add pop to the end of the block */
796 addiCodeToeBBlock (ebp, nic, NULL);
805 /*-----------------------------------------------------------------*/
806 /* getRegPtr - will try for PTR if not a GPR type if not spil */
807 /*-----------------------------------------------------------------*/
809 getRegPtr (iCode * ic, eBBlock * ebp, symbol * sym)
814 /* try for a ptr type */
815 if ((reg = allocReg (REG_PTR)))
818 /* try for gpr type */
819 if ((reg = allocReg (REG_GPR)))
822 /* we have to spil */
823 if (!spilSomething (ic, ebp, sym))
826 /* this looks like an infinite loop but
827 in really selectSpil will abort */
831 /*-----------------------------------------------------------------*/
832 /* getRegGpr - will try for GPR if not spil */
833 /*-----------------------------------------------------------------*/
835 getRegGpr (iCode * ic, eBBlock * ebp, symbol * sym)
840 /* try for gpr type */
841 if ((reg = allocReg (REG_GPR)))
844 if (!mcs51_ptrRegReq)
845 if ((reg = allocReg (REG_PTR)))
848 /* we have to spil */
849 if (!spilSomething (ic, ebp, sym))
852 /* this looks like an infinite loop but
853 in really selectSpil will abort */
857 /*-----------------------------------------------------------------*/
858 /* symHasReg - symbol has a given register */
859 /*-----------------------------------------------------------------*/
861 symHasReg (symbol * sym, regs * reg)
865 for (i = 0; i < sym->nRegs; i++)
866 if (sym->regs[i] == reg)
872 /*-----------------------------------------------------------------*/
873 /* deassignLRs - check the live to and if they have registers & are */
874 /* not spilt then free up the registers */
875 /*-----------------------------------------------------------------*/
877 deassignLRs (iCode * ic, eBBlock * ebp)
883 for (sym = hTabFirstItem (liveRanges, &k); sym;
884 sym = hTabNextItem (liveRanges, &k))
888 /* if it does not end here */
889 if (sym->liveTo > ic->seq)
892 /* if it was spilt on stack then we can
893 mark the stack spil location as free */
898 sym->usl.spillLoc->isFree = 1;
904 if (!bitVectBitValue (_G.regAssigned, sym->key))
907 /* special case check if this is an IFX &
908 the privious one was a pop and the
909 previous one was not spilt then keep track
911 if (ic->op == IFX && ic->prev &&
912 ic->prev->op == IPOP &&
913 !ic->prev->parmPush &&
914 !OP_SYMBOL (IC_LEFT (ic->prev))->isspilt)
915 psym = OP_SYMBOL (IC_LEFT (ic->prev));
921 bitVectUnSetBit (_G.regAssigned, sym->key);
923 /* if the result of this one needs registers
924 and does not have it then assign it right
926 if (IC_RESULT (ic) &&
927 !(SKIP_IC2 (ic) || /* not a special icode */
928 ic->op == JUMPTABLE ||
934 (result = OP_SYMBOL (IC_RESULT (ic))) && /* has a result */
935 result->liveTo > ic->seq && /* and will live beyond this */
936 result->liveTo <= ebp->lSeq && /* does not go beyond this block */
937 result->regType == sym->regType && /* same register types */
938 result->nRegs && /* which needs registers */
939 !result->isspilt && /* and does not already have them */
941 !bitVectBitValue (_G.regAssigned, result->key) &&
942 /* the number of free regs + number of regs in this LR
943 can accomodate the what result Needs */
944 ((nfreeRegsType (result->regType) +
945 sym->nRegs) >= result->nRegs)
949 for (i = 0; i < result->nRegs; i++)
951 result->regs[i] = sym->regs[i];
953 result->regs[i] = getRegGpr (ic, ebp, result);
955 _G.regAssigned = bitVectSetBit (_G.regAssigned, result->key);
959 /* free the remaining */
960 for (; i < sym->nRegs; i++)
964 if (!symHasReg (psym, sym->regs[i]))
965 freeReg (sym->regs[i]);
968 freeReg (sym->regs[i]);
975 /*-----------------------------------------------------------------*/
976 /* reassignLR - reassign this to registers */
977 /*-----------------------------------------------------------------*/
979 reassignLR (operand * op)
981 symbol *sym = OP_SYMBOL (op);
984 /* not spilt any more */
985 sym->isspilt = sym->blockSpil = sym->remainSpil = 0;
986 bitVectUnSetBit (_G.spiltSet, sym->key);
988 _G.regAssigned = bitVectSetBit (_G.regAssigned, sym->key);
992 for (i = 0; i < sym->nRegs; i++)
993 sym->regs[i]->isFree = 0;
996 /*-----------------------------------------------------------------*/
997 /* willCauseSpill - determines if allocating will cause a spill */
998 /*-----------------------------------------------------------------*/
1000 willCauseSpill (int nr, int rt)
1002 /* first check if there are any avlb registers
1003 of te type required */
1006 /* special case for pointer type
1007 if pointer type not avlb then
1008 check for type gpr */
1009 if (nFreeRegs (rt) >= nr)
1011 if (nFreeRegs (REG_GPR) >= nr)
1016 if (mcs51_ptrRegReq)
1018 if (nFreeRegs (rt) >= nr)
1023 if (nFreeRegs (REG_PTR) +
1024 nFreeRegs (REG_GPR) >= nr)
1029 /* it will cause a spil */
1033 /*-----------------------------------------------------------------*/
1034 /* positionRegs - the allocator can allocate same registers to res- */
1035 /* ult and operand, if this happens make sure they are in the same */
1036 /* position as the operand otherwise chaos results */
1037 /*-----------------------------------------------------------------*/
1039 positionRegs (symbol * result, symbol * opsym, int lineno)
1041 int count = min (result->nRegs, opsym->nRegs);
1042 int i, j = 0, shared = 0;
1044 /* if the result has been spilt then cannot share */
1049 /* first make sure that they actually share */
1050 for (i = 0; i < count; i++)
1052 for (j = 0; j < count; j++)
1054 if (result->regs[i] == opsym->regs[j] && i != j)
1064 regs *tmp = result->regs[i];
1065 result->regs[i] = result->regs[j];
1066 result->regs[j] = tmp;
1071 /*-----------------------------------------------------------------*/
1072 /* serialRegAssign - serially allocate registers to the variables */
1073 /*-----------------------------------------------------------------*/
1075 serialRegAssign (eBBlock ** ebbs, int count)
1079 /* for all blocks */
1080 for (i = 0; i < count; i++)
1085 if (ebbs[i]->noPath &&
1086 (ebbs[i]->entryLabel != entryLabel &&
1087 ebbs[i]->entryLabel != returnLabel))
1090 /* of all instructions do */
1091 for (ic = ebbs[i]->sch; ic; ic = ic->next)
1094 /* if this is an ipop that means some live
1095 range will have to be assigned again */
1097 reassignLR (IC_LEFT (ic));
1099 /* if result is present && is a true symbol */
1100 if (IC_RESULT (ic) && ic->op != IFX &&
1101 IS_TRUE_SYMOP (IC_RESULT (ic)))
1102 OP_SYMBOL (IC_RESULT (ic))->allocreq = 1;
1104 /* take away registers from live
1105 ranges that end at this instruction */
1106 deassignLRs (ic, ebbs[i]);
1108 /* some don't need registers */
1109 if (SKIP_IC2 (ic) ||
1110 ic->op == JUMPTABLE ||
1114 (IC_RESULT (ic) && POINTER_SET (ic)))
1117 /* now we need to allocate registers
1118 only for the result */
1121 symbol *sym = OP_SYMBOL (IC_RESULT (ic));
1127 /* if it does not need or is spilt
1128 or is already assigned to registers
1129 or will not live beyond this instructions */
1132 bitVectBitValue (_G.regAssigned, sym->key) ||
1133 sym->liveTo <= ic->seq)
1136 /* if some liverange has been spilt at the block level
1137 and this one live beyond this block then spil this
1139 if (_G.blockSpil && sym->liveTo > ebbs[i]->lSeq)
1144 /* if trying to allocate this will cause
1145 a spill and there is nothing to spill
1146 or this one is rematerializable then
1148 willCS = willCauseSpill (sym->nRegs, sym->regType);
1149 spillable = computeSpillable (ic);
1151 (willCS && bitVectIsZero (spillable)))
1159 /* if it has a spillocation & is used less than
1160 all other live ranges then spill this */
1161 if (willCS && sym->usl.spillLoc)
1165 leastUsedLR (liveRangesWith (spillable,
1170 leastUsed->used > sym->used)
1177 /* if we need ptr regs for the right side
1179 if (POINTER_GET (ic) && IS_SYMOP (IC_LEFT (ic))
1180 && getSize (OP_SYMBOL (IC_LEFT (ic))->type)
1186 /* else we assign registers to it */
1187 _G.regAssigned = bitVectSetBit (_G.regAssigned, sym->key);
1189 for (j = 0; j < sym->nRegs; j++)
1191 if (sym->regType == REG_PTR)
1192 sym->regs[j] = getRegPtr (ic, ebbs[i], sym);
1194 sym->regs[j] = getRegGpr (ic, ebbs[i], sym);
1196 /* if the allocation falied which means
1197 this was spilt then break */
1201 /* if it shares registers with operands make sure
1202 that they are in the same position */
1203 if (IC_LEFT (ic) && IS_SYMOP (IC_LEFT (ic)) &&
1204 OP_SYMBOL (IC_LEFT (ic))->nRegs && ic->op != '=')
1205 positionRegs (OP_SYMBOL (IC_RESULT (ic)),
1206 OP_SYMBOL (IC_LEFT (ic)), ic->lineno);
1207 /* do the same for the right operand */
1208 if (IC_RIGHT (ic) && IS_SYMOP (IC_RIGHT (ic)) &&
1209 OP_SYMBOL (IC_RIGHT (ic))->nRegs)
1210 positionRegs (OP_SYMBOL (IC_RESULT (ic)),
1211 OP_SYMBOL (IC_RIGHT (ic)), ic->lineno);
1224 /*-----------------------------------------------------------------*/
1225 /* rUmaskForOp :- returns register mask for an operand */
1226 /*-----------------------------------------------------------------*/
1228 rUmaskForOp (operand * op)
1234 /* only temporaries are assigned registers */
1238 sym = OP_SYMBOL (op);
1240 /* if spilt or no registers assigned to it
1242 if (sym->isspilt || !sym->nRegs)
1245 rumask = newBitVect (mcs51_nRegs);
1247 for (j = 0; j < sym->nRegs; j++)
1249 rumask = bitVectSetBit (rumask,
1250 sym->regs[j]->rIdx);
1256 /*-----------------------------------------------------------------*/
1257 /* regsUsedIniCode :- returns bit vector of registers used in iCode */
1258 /*-----------------------------------------------------------------*/
1260 regsUsedIniCode (iCode * ic)
1262 bitVect *rmask = newBitVect (mcs51_nRegs);
1264 /* do the special cases first */
1267 rmask = bitVectUnion (rmask,
1268 rUmaskForOp (IC_COND (ic)));
1272 /* for the jumptable */
1273 if (ic->op == JUMPTABLE)
1275 rmask = bitVectUnion (rmask,
1276 rUmaskForOp (IC_JTCOND (ic)));
1281 /* of all other cases */
1283 rmask = bitVectUnion (rmask,
1284 rUmaskForOp (IC_LEFT (ic)));
1288 rmask = bitVectUnion (rmask,
1289 rUmaskForOp (IC_RIGHT (ic)));
1292 rmask = bitVectUnion (rmask,
1293 rUmaskForOp (IC_RESULT (ic)));
1299 /*-----------------------------------------------------------------*/
1300 /* createRegMask - for each instruction will determine the regsUsed */
1301 /*-----------------------------------------------------------------*/
1303 createRegMask (eBBlock ** ebbs, int count)
1307 /* for all blocks */
1308 for (i = 0; i < count; i++)
1312 if (ebbs[i]->noPath &&
1313 (ebbs[i]->entryLabel != entryLabel &&
1314 ebbs[i]->entryLabel != returnLabel))
1317 /* for all instructions */
1318 for (ic = ebbs[i]->sch; ic; ic = ic->next)
1323 if (SKIP_IC2 (ic) || !ic->rlive)
1326 /* first mark the registers used in this
1328 ic->rUsed = regsUsedIniCode (ic);
1329 _G.funcrUsed = bitVectUnion (_G.funcrUsed, ic->rUsed);
1331 /* now create the register mask for those
1332 registers that are in use : this is a
1333 super set of ic->rUsed */
1334 ic->rMask = newBitVect (mcs51_nRegs + 1);
1336 /* for all live Ranges alive at this point */
1337 for (j = 1; j < ic->rlive->size; j++)
1342 /* if not alive then continue */
1343 if (!bitVectBitValue (ic->rlive, j))
1346 /* find the live range we are interested in */
1347 if (!(sym = hTabItemWithKey (liveRanges, j)))
1349 werror (E_INTERNAL_ERROR, __FILE__, __LINE__,
1350 "createRegMask cannot find live range");
1354 /* if no register assigned to it */
1355 if (!sym->nRegs || sym->isspilt)
1358 /* for all the registers allocated to it */
1359 for (k = 0; k < sym->nRegs; k++)
1362 bitVectSetBit (ic->rMask, sym->regs[k]->rIdx);
1368 /*-----------------------------------------------------------------*/
1369 /* rematStr - returns the rematerialized string for a remat var */
1370 /*-----------------------------------------------------------------*/
1372 rematStr (symbol * sym)
1375 iCode *ic = sym->rematiCode;
1380 /* if plus or minus print the right hand side */
1381 if (ic->op == '+' || ic->op == '-')
1383 sprintf (s, "0x%04x %c ", (int) operandLitValue (IC_RIGHT (ic)),
1386 ic = OP_SYMBOL (IC_LEFT (ic))->rematiCode;
1390 /* we reached the end */
1391 sprintf (s, "%s", OP_SYMBOL (IC_LEFT (ic))->rname);
1398 /*-----------------------------------------------------------------*/
1399 /* regTypeNum - computes the type & number of registers required */
1400 /*-----------------------------------------------------------------*/
1408 /* for each live range do */
1409 for (sym = hTabFirstItem (liveRanges, &k); sym;
1410 sym = hTabNextItem (liveRanges, &k))
1413 /* if used zero times then no registers needed */
1414 if ((sym->liveTo - sym->liveFrom) == 0)
1418 /* if the live range is a temporary */
1422 /* if the type is marked as a conditional */
1423 if (sym->regType == REG_CND)
1426 /* if used in return only then we don't
1428 if (sym->ruonly || sym->accuse)
1430 if (IS_AGGREGATE (sym->type) || sym->isptr)
1431 sym->type = aggrToPtr (sym->type, FALSE);
1435 /* if the symbol has only one definition &
1436 that definition is a get_pointer and the
1437 pointer we are getting is rematerializable and
1440 if (bitVectnBitsOn (sym->defs) == 1 &&
1441 (ic = hTabItemWithKey (iCodehTab,
1442 bitVectFirstBit (sym->defs))) &&
1444 !IS_BITVAR (sym->etype))
1448 /* if remat in data space */
1449 if (OP_SYMBOL (IC_LEFT (ic))->remat &&
1450 DCL_TYPE (aggrToPtr (sym->type, FALSE)) == POINTER)
1453 /* create a psuedo symbol & force a spil */
1454 symbol *psym = newSymbol (rematStr (OP_SYMBOL (IC_LEFT (ic))), 1);
1455 psym->type = sym->type;
1456 psym->etype = sym->etype;
1457 strcpy (psym->rname, psym->name);
1459 sym->usl.spillLoc = psym;
1463 /* if in data space or idata space then try to
1464 allocate pointer register */
1468 /* if not then we require registers */
1469 sym->nRegs = ((IS_AGGREGATE (sym->type) || sym->isptr) ?
1470 getSize (sym->type = aggrToPtr (sym->type, FALSE)) :
1471 getSize (sym->type));
1475 fprintf (stderr, "allocated more than 4 or 0 registers for type ");
1476 printTypeChain (sym->type, stderr);
1477 fprintf (stderr, "\n");
1480 /* determine the type of register required */
1481 if (sym->nRegs == 1 &&
1482 IS_PTR (sym->type) &&
1484 sym->regType = REG_PTR;
1486 sym->regType = REG_GPR;
1490 /* for the first run we don't provide */
1491 /* registers for true symbols we will */
1492 /* see how things go */
1498 /*-----------------------------------------------------------------*/
1499 /* freeAllRegs - mark all registers as free */
1500 /*-----------------------------------------------------------------*/
1506 for (i = 0; i < mcs51_nRegs; i++)
1507 regs8051[i].isFree = 1;
1510 /*-----------------------------------------------------------------*/
1511 /* deallocStackSpil - this will set the stack pointer back */
1512 /*-----------------------------------------------------------------*/
1514 DEFSETFUNC (deallocStackSpil)
1522 /*-----------------------------------------------------------------*/
1523 /* farSpacePackable - returns the packable icode for far variables */
1524 /*-----------------------------------------------------------------*/
1526 farSpacePackable (iCode * ic)
1530 /* go thru till we find a definition for the
1531 symbol on the right */
1532 for (dic = ic->prev; dic; dic = dic->prev)
1534 /* if the definition is a call then no */
1535 if ((dic->op == CALL || dic->op == PCALL) &&
1536 IC_RESULT (dic)->key == IC_RIGHT (ic)->key)
1541 /* if shift by unknown amount then not */
1542 if ((dic->op == LEFT_OP || dic->op == RIGHT_OP) &&
1543 IC_RESULT (dic)->key == IC_RIGHT (ic)->key)
1546 /* if pointer get and size > 1 */
1547 if (POINTER_GET (dic) &&
1548 getSize (aggrToPtr (operandType (IC_LEFT (dic)), FALSE)) > 1)
1551 if (POINTER_SET (dic) &&
1552 getSize (aggrToPtr (operandType (IC_RESULT (dic)), FALSE)) > 1)
1555 /* if any three is a true symbol in far space */
1556 if (IC_RESULT (dic) &&
1557 IS_TRUE_SYMOP (IC_RESULT (dic)) &&
1558 isOperandInFarSpace (IC_RESULT (dic)))
1561 if (IC_RIGHT (dic) &&
1562 IS_TRUE_SYMOP (IC_RIGHT (dic)) &&
1563 isOperandInFarSpace (IC_RIGHT (dic)) &&
1564 !isOperandEqual (IC_RIGHT (dic), IC_RESULT (ic)))
1567 if (IC_LEFT (dic) &&
1568 IS_TRUE_SYMOP (IC_LEFT (dic)) &&
1569 isOperandInFarSpace (IC_LEFT (dic)) &&
1570 !isOperandEqual (IC_LEFT (dic), IC_RESULT (ic)))
1573 if (isOperandEqual (IC_RIGHT (ic), IC_RESULT (dic)))
1575 if ((dic->op == LEFT_OP ||
1576 dic->op == RIGHT_OP ||
1578 IS_OP_LITERAL (IC_RIGHT (dic)))
1588 /*-----------------------------------------------------------------*/
1589 /* packRegsForAssign - register reduction for assignment */
1590 /*-----------------------------------------------------------------*/
1592 packRegsForAssign (iCode * ic, eBBlock * ebp)
1595 sym_link *etype = operandType (IC_RIGHT (ic));
1597 if (!IS_ITEMP (IC_RIGHT (ic)) ||
1598 OP_SYMBOL (IC_RIGHT (ic))->isind ||
1599 OP_LIVETO (IC_RIGHT (ic)) > ic->seq ||
1600 IS_BITFIELD (etype))
1605 /* if the true symbol is defined in far space or on stack
1606 then we should not since this will increase register pressure */
1608 if (isOperandInFarSpace (IC_RESULT (ic)))
1610 if ((dic = farSpacePackable (ic)))
1616 if (isOperandInFarSpace(IC_RESULT(ic)) && !farSpacePackable(ic)) {
1621 /* find the definition of iTempNN scanning backwards if we find a
1622 a use of the true symbol in before we find the definition then
1624 for (dic = ic->prev; dic; dic = dic->prev)
1627 /* if there is a function call and this is
1628 a parameter & not my parameter then don't pack it */
1629 if ((dic->op == CALL || dic->op == PCALL) &&
1630 (OP_SYMBOL (IC_RESULT (ic))->_isparm &&
1631 !OP_SYMBOL (IC_RESULT (ic))->ismyparm))
1640 if (IS_TRUE_SYMOP (IC_RESULT (dic)) &&
1641 IS_OP_VOLATILE (IC_RESULT (dic)))
1647 if (IS_SYMOP (IC_RESULT (dic)) &&
1648 IC_RESULT (dic)->key == IC_RIGHT (ic)->key)
1650 if (POINTER_SET (dic))
1656 if (IS_SYMOP (IC_RIGHT (dic)) &&
1657 (IC_RIGHT (dic)->key == IC_RESULT (ic)->key ||
1658 IC_RIGHT (dic)->key == IC_RIGHT (ic)->key))
1664 if (IS_SYMOP (IC_LEFT (dic)) &&
1665 (IC_LEFT (dic)->key == IC_RESULT (ic)->key ||
1666 IC_LEFT (dic)->key == IC_RIGHT (ic)->key))
1672 if (POINTER_SET (dic) &&
1673 IC_RESULT (dic)->key == IC_RESULT (ic)->key)
1681 return 0; /* did not find */
1683 /* if assignment then check that right is not a bit */
1684 if (ASSIGNMENT (dic) && !POINTER_SET (dic))
1686 sym_link *etype = operandType (IC_RIGHT (dic));
1687 if (IS_BITFIELD (etype))
1690 /* if the result is on stack or iaccess then it must be
1691 the same atleast one of the operands */
1692 if (OP_SYMBOL (IC_RESULT (ic))->onStack ||
1693 OP_SYMBOL (IC_RESULT (ic))->iaccess)
1696 /* the operation has only one symbol
1697 operator then we can pack */
1698 if ((IC_LEFT (dic) && !IS_SYMOP (IC_LEFT (dic))) ||
1699 (IC_RIGHT (dic) && !IS_SYMOP (IC_RIGHT (dic))))
1702 if (!((IC_LEFT (dic) &&
1703 IC_RESULT (ic)->key == IC_LEFT (dic)->key) ||
1705 IC_RESULT (ic)->key == IC_RIGHT (dic)->key)))
1709 /* found the definition */
1710 /* replace the result with the result of */
1711 /* this assignment and remove this assignment */
1712 IC_RESULT (dic) = IC_RESULT (ic);
1714 if (IS_ITEMP (IC_RESULT (dic)) && OP_SYMBOL (IC_RESULT (dic))->liveFrom > dic->seq)
1716 OP_SYMBOL (IC_RESULT (dic))->liveFrom = dic->seq;
1718 /* delete from liverange table also
1719 delete from all the points inbetween and the new
1721 for (sic = dic; sic != ic; sic = sic->next)
1723 bitVectUnSetBit (sic->rlive, IC_RESULT (ic)->key);
1724 if (IS_ITEMP (IC_RESULT (dic)))
1725 bitVectSetBit (sic->rlive, IC_RESULT (dic)->key);
1728 remiCodeFromeBBlock (ebp, ic);
1729 hTabDeleteItem (&iCodehTab, ic->key, ic, DELETE_ITEM, NULL);
1730 OP_DEFS (IC_RESULT (dic)) = bitVectSetBit (OP_DEFS (IC_RESULT (dic)), dic->key);
1735 /*-----------------------------------------------------------------*/
1736 /* findAssignToSym : scanning backwards looks for first assig found */
1737 /*-----------------------------------------------------------------*/
1739 findAssignToSym (operand * op, iCode * ic)
1743 for (dic = ic->prev; dic; dic = dic->prev)
1746 /* if definition by assignment */
1747 if (dic->op == '=' &&
1748 !POINTER_SET (dic) &&
1749 IC_RESULT (dic)->key == op->key
1750 /* && IS_TRUE_SYMOP(IC_RIGHT(dic)) */
1754 /* we are interested only if defined in far space */
1755 /* or in stack space in case of + & - */
1757 /* if assigned to a non-symbol then return
1759 if (!IS_SYMOP (IC_RIGHT (dic)))
1762 /* if the symbol is in far space then
1764 if (isOperandInFarSpace (IC_RIGHT (dic)))
1767 /* for + & - operations make sure that
1768 if it is on the stack it is the same
1769 as one of the three operands */
1770 if ((ic->op == '+' || ic->op == '-') &&
1771 OP_SYMBOL (IC_RIGHT (dic))->onStack)
1774 if (IC_RESULT (ic)->key != IC_RIGHT (dic)->key &&
1775 IC_LEFT (ic)->key != IC_RIGHT (dic)->key &&
1776 IC_RIGHT (ic)->key != IC_RIGHT (dic)->key)
1784 /* if we find an usage then we cannot delete it */
1785 if (IC_LEFT (dic) && IC_LEFT (dic)->key == op->key)
1788 if (IC_RIGHT (dic) && IC_RIGHT (dic)->key == op->key)
1791 if (POINTER_SET (dic) && IC_RESULT (dic)->key == op->key)
1795 /* now make sure that the right side of dic
1796 is not defined between ic & dic */
1799 iCode *sic = dic->next;
1801 for (; sic != ic; sic = sic->next)
1802 if (IC_RESULT (sic) &&
1803 IC_RESULT (sic)->key == IC_RIGHT (dic)->key)
1812 /*-----------------------------------------------------------------*/
1813 /* packRegsForSupport :- reduce some registers for support calls */
1814 /*-----------------------------------------------------------------*/
1816 packRegsForSupport (iCode * ic, eBBlock * ebp)
1819 /* for the left & right operand :- look to see if the
1820 left was assigned a true symbol in far space in that
1821 case replace them */
1823 if (IS_ITEMP (IC_LEFT (ic)) &&
1824 OP_SYMBOL (IC_LEFT (ic))->liveTo <= ic->seq)
1826 iCode *dic = findAssignToSym (IC_LEFT (ic), ic);
1832 /* found it we need to remove it from the
1834 for (sic = dic; sic != ic; sic = sic->next)
1835 bitVectUnSetBit (sic->rlive, IC_LEFT (ic)->key);
1837 IC_LEFT (ic)->operand.symOperand =
1838 IC_RIGHT (dic)->operand.symOperand;
1839 IC_LEFT (ic)->key = IC_RIGHT (dic)->operand.symOperand->key;
1840 remiCodeFromeBBlock (ebp, dic);
1841 hTabDeleteItem (&iCodehTab, dic->key, dic, DELETE_ITEM, NULL);
1845 /* do the same for the right operand */
1848 IS_ITEMP (IC_RIGHT (ic)) &&
1849 OP_SYMBOL (IC_RIGHT (ic))->liveTo <= ic->seq)
1851 iCode *dic = findAssignToSym (IC_RIGHT (ic), ic);
1857 /* if this is a subtraction & the result
1858 is a true symbol in far space then don't pack */
1859 if (ic->op == '-' && IS_TRUE_SYMOP (IC_RESULT (dic)))
1861 sym_link *etype = getSpec (operandType (IC_RESULT (dic)));
1862 if (IN_FARSPACE (SPEC_OCLS (etype)))
1865 /* found it we need to remove it from the
1867 for (sic = dic; sic != ic; sic = sic->next)
1868 bitVectUnSetBit (sic->rlive, IC_RIGHT (ic)->key);
1870 IC_RIGHT (ic)->operand.symOperand =
1871 IC_RIGHT (dic)->operand.symOperand;
1872 IC_RIGHT (ic)->key = IC_RIGHT (dic)->operand.symOperand->key;
1874 remiCodeFromeBBlock (ebp, dic);
1875 hTabDeleteItem (&iCodehTab, dic->key, dic, DELETE_ITEM, NULL);
1882 #define IS_OP_RUONLY(x) (x && IS_SYMOP(x) && OP_SYMBOL(x)->ruonly)
1885 /*-----------------------------------------------------------------*/
1886 /* packRegsForOneuse : - will reduce some registers for single Use */
1887 /*-----------------------------------------------------------------*/
1889 packRegsForOneuse (iCode * ic, operand * op, eBBlock * ebp)
1894 /* if returning a literal then do nothing */
1898 /* only upto 2 bytes since we cannot predict
1899 the usage of b, & acc */
1900 if (getSize (operandType (op)) > (fReturnSizeMCS51 - 2) &&
1903 !POINTER_SET (ic) &&
1907 /* this routine will mark the a symbol as used in one
1908 instruction use only && if the defintion is local
1909 (ie. within the basic block) && has only one definition &&
1910 that definiion is either a return value from a
1911 function or does not contain any variables in
1913 uses = bitVectCopy (OP_USES (op));
1914 bitVectUnSetBit (uses, ic->key); /* take away this iCode */
1915 if (!bitVectIsZero (uses)) /* has other uses */
1918 /* if it has only one defintion */
1919 if (bitVectnBitsOn (OP_DEFS (op)) > 1)
1920 return NULL; /* has more than one definition */
1922 /* get that definition */
1924 hTabItemWithKey (iCodehTab,
1925 bitVectFirstBit (OP_DEFS (op)))))
1928 /* found the definition now check if it is local */
1929 if (dic->seq < ebp->fSeq ||
1930 dic->seq > ebp->lSeq)
1931 return NULL; /* non-local */
1933 /* now check if it is the return from
1935 if (dic->op == CALL || dic->op == PCALL)
1937 if (ic->op != SEND && ic->op != RETURN)
1939 OP_SYMBOL (op)->ruonly = 1;
1946 /* otherwise check that the definition does
1947 not contain any symbols in far space */
1948 if (isOperandInFarSpace (IC_LEFT (dic)) ||
1949 isOperandInFarSpace (IC_RIGHT (dic)) ||
1950 IS_OP_RUONLY (IC_LEFT (ic)) ||
1951 IS_OP_RUONLY (IC_RIGHT (ic)))
1956 /* if pointer set then make sure the pointer
1958 if (POINTER_SET (dic) &&
1959 !IS_DATA_PTR (aggrToPtr (operandType (IC_RESULT (dic)), FALSE)))
1962 if (POINTER_GET (dic) &&
1963 !IS_DATA_PTR (aggrToPtr (operandType (IC_LEFT (dic)), FALSE)))
1968 /* also make sure the intervenening instructions
1969 don't have any thing in far space */
1970 for (dic = dic->next; dic && dic != ic && sic != ic; dic = dic->next)
1973 /* if there is an intervening function call then no */
1974 if (dic->op == CALL || dic->op == PCALL)
1976 /* if pointer set then make sure the pointer
1978 if (POINTER_SET (dic) &&
1979 !IS_DATA_PTR (aggrToPtr (operandType (IC_RESULT (dic)), FALSE)))
1982 if (POINTER_GET (dic) &&
1983 !IS_DATA_PTR (aggrToPtr (operandType (IC_LEFT (dic)), FALSE)))
1986 /* if address of & the result is remat the okay */
1987 if (dic->op == ADDRESS_OF &&
1988 OP_SYMBOL (IC_RESULT (dic))->remat)
1991 /* if operand has size of three or more & this
1992 operation is a '*','/' or '%' then 'b' may
1994 if ((dic->op == '%' || dic->op == '/' || dic->op == '*') &&
1995 getSize (operandType (op)) >= 3)
1998 /* if left or right or result is in far space */
1999 if (isOperandInFarSpace (IC_LEFT (dic)) ||
2000 isOperandInFarSpace (IC_RIGHT (dic)) ||
2001 isOperandInFarSpace (IC_RESULT (dic)) ||
2002 IS_OP_RUONLY (IC_LEFT (dic)) ||
2003 IS_OP_RUONLY (IC_RIGHT (dic)) ||
2004 IS_OP_RUONLY (IC_RESULT (dic)))
2008 /* if left or right or result is on stack */
2009 if (isOperandOnStack(IC_LEFT(dic)) ||
2010 isOperandOnStack(IC_RIGHT(dic)) ||
2011 isOperandOnStack(IC_RESULT(dic))) {
2016 OP_SYMBOL (op)->ruonly = 1;
2021 /*-----------------------------------------------------------------*/
2022 /* isBitwiseOptimizable - requirements of JEAN LOUIS VERN */
2023 /*-----------------------------------------------------------------*/
2025 isBitwiseOptimizable (iCode * ic)
2027 sym_link *ltype = getSpec (operandType (IC_LEFT (ic)));
2029 /* bitwise operations are considered optimizable
2030 under the following conditions (Jean-Louis VERN)
2039 if ((IS_BITVAR (ltype) && IN_BITSPACE (SPEC_OCLS (ltype))))
2045 /*-----------------------------------------------------------------*/
2046 /* packRegsForAccUse - pack registers for acc use */
2047 /*-----------------------------------------------------------------*/
2049 packRegsForAccUse (iCode * ic)
2053 /* if + or - then it has to be one byte result */
2054 if ((ic->op == '+' || ic->op == '-')
2055 && getSize (operandType (IC_RESULT (ic))) > 1)
2058 /* if shift operation make sure right side is not a literal */
2059 if (ic->op == RIGHT_OP &&
2060 (isOperandLiteral (IC_RIGHT (ic)) ||
2061 getSize (operandType (IC_RESULT (ic))) > 1))
2064 if (ic->op == LEFT_OP &&
2065 (isOperandLiteral (IC_RIGHT (ic)) ||
2066 getSize (operandType (IC_RESULT (ic))) > 1))
2069 if (IS_BITWISE_OP (ic) &&
2070 getSize (operandType (IC_RESULT (ic))) > 1)
2074 /* has only one definition */
2075 if (bitVectnBitsOn (OP_DEFS (IC_RESULT (ic))) > 1)
2078 /* has only one use */
2079 if (bitVectnBitsOn (OP_USES (IC_RESULT (ic))) > 1)
2082 /* and the usage immediately follows this iCode */
2083 if (!(uic = hTabItemWithKey (iCodehTab,
2084 bitVectFirstBit (OP_USES (IC_RESULT (ic))))))
2087 if (ic->next != uic)
2090 /* if it is a conditional branch then we definitely can */
2094 if (uic->op == JUMPTABLE)
2097 /* if the usage is not is an assignment
2098 or an arithmetic / bitwise / shift operation then not */
2099 if (POINTER_SET (uic) &&
2100 getSize (aggrToPtr (operandType (IC_RESULT (uic)), FALSE)) > 1)
2103 if (uic->op != '=' &&
2104 !IS_ARITHMETIC_OP (uic) &&
2105 !IS_BITWISE_OP (uic) &&
2106 uic->op != LEFT_OP &&
2107 uic->op != RIGHT_OP)
2110 /* if used in ^ operation then make sure right is not a
2112 if (uic->op == '^' && isOperandLiteral (IC_RIGHT (uic)))
2115 /* if shift operation make sure right side is not a literal */
2116 if (uic->op == RIGHT_OP &&
2117 (isOperandLiteral (IC_RIGHT (uic)) ||
2118 getSize (operandType (IC_RESULT (uic))) > 1))
2121 if (uic->op == LEFT_OP &&
2122 (isOperandLiteral (IC_RIGHT (uic)) ||
2123 getSize (operandType (IC_RESULT (uic))) > 1))
2126 /* make sure that the result of this icode is not on the
2127 stack, since acc is used to compute stack offset */
2128 if (IS_TRUE_SYMOP (IC_RESULT (uic)) &&
2129 OP_SYMBOL (IC_RESULT (uic))->onStack)
2132 /* if either one of them in far space then we cannot */
2133 if ((IS_TRUE_SYMOP (IC_LEFT (uic)) &&
2134 isOperandInFarSpace (IC_LEFT (uic))) ||
2135 (IS_TRUE_SYMOP (IC_RIGHT (uic)) &&
2136 isOperandInFarSpace (IC_RIGHT (uic))))
2139 /* if the usage has only one operand then we can */
2140 if (IC_LEFT (uic) == NULL ||
2141 IC_RIGHT (uic) == NULL)
2144 /* make sure this is on the left side if not
2145 a '+' since '+' is commutative */
2146 if (ic->op != '+' &&
2147 IC_LEFT (uic)->key != IC_RESULT (ic)->key)
2150 /* if one of them is a literal then we can */
2151 if ((IC_LEFT (uic) && IS_OP_LITERAL (IC_LEFT (uic))) ||
2152 (IC_RIGHT (uic) && IS_OP_LITERAL (IC_RIGHT (uic))))
2154 OP_SYMBOL (IC_RESULT (ic))->accuse = 1;
2158 /* if the other one is not on stack then we can */
2159 if (IC_LEFT (uic)->key == IC_RESULT (ic)->key &&
2160 (IS_ITEMP (IC_RIGHT (uic)) ||
2161 (IS_TRUE_SYMOP (IC_RIGHT (uic)) &&
2162 !OP_SYMBOL (IC_RIGHT (uic))->onStack)))
2165 if (IC_RIGHT (uic)->key == IC_RESULT (ic)->key &&
2166 (IS_ITEMP (IC_LEFT (uic)) ||
2167 (IS_TRUE_SYMOP (IC_LEFT (uic)) &&
2168 !OP_SYMBOL (IC_LEFT (uic))->onStack)))
2174 OP_SYMBOL (IC_RESULT (ic))->accuse = 1;
2179 /*-----------------------------------------------------------------*/
2180 /* packForPush - hueristics to reduce iCode for pushing */
2181 /*-----------------------------------------------------------------*/
2183 packForPush (iCode * ic, eBBlock * ebp)
2188 if (ic->op != IPUSH || !IS_ITEMP (IC_LEFT (ic)))
2191 /* must have only definition & one usage */
2192 if (bitVectnBitsOn (OP_DEFS (IC_LEFT (ic))) != 1 ||
2193 bitVectnBitsOn (OP_USES (IC_LEFT (ic))) != 1)
2196 /* find the definition */
2197 if (!(dic = hTabItemWithKey (iCodehTab,
2198 bitVectFirstBit (OP_DEFS (IC_LEFT (ic))))))
2201 if (dic->op != '=' || POINTER_SET (dic))
2204 /* make sure the right side does not have any definitions
2206 dbv = OP_DEFS(IC_RIGHT(dic));
2207 for (lic = ic; lic && lic != dic ; lic = lic->prev) {
2208 if (bitVectBitValue(dbv,lic->key))
2211 /* we now we know that it has one & only one def & use
2212 and the that the definition is an assignment */
2213 IC_LEFT (ic) = IC_RIGHT (dic);
2215 remiCodeFromeBBlock (ebp, dic);
2216 hTabDeleteItem (&iCodehTab, dic->key, dic, DELETE_ITEM, NULL);
2219 /*-----------------------------------------------------------------*/
2220 /* packRegisters - does some transformations to reduce register */
2222 /*-----------------------------------------------------------------*/
2224 packRegisters (eBBlock * ebp)
2234 /* look for assignments of the form */
2235 /* iTempNN = TRueSym (someoperation) SomeOperand */
2237 /* TrueSym := iTempNN:1 */
2238 for (ic = ebp->sch; ic; ic = ic->next)
2240 /* find assignment of the form TrueSym := iTempNN:1 */
2241 if (ic->op == '=' && !POINTER_SET (ic))
2242 change += packRegsForAssign (ic, ebp);
2249 for (ic = ebp->sch; ic; ic = ic->next)
2251 /* if this is an itemp & result of a address of a true sym
2252 then mark this as rematerialisable */
2253 if (ic->op == ADDRESS_OF &&
2254 IS_ITEMP (IC_RESULT (ic)) &&
2255 IS_TRUE_SYMOP (IC_LEFT (ic)) &&
2256 bitVectnBitsOn (OP_DEFS (IC_RESULT (ic))) == 1 &&
2257 !OP_SYMBOL (IC_LEFT (ic))->onStack)
2260 OP_SYMBOL (IC_RESULT (ic))->remat = 1;
2261 OP_SYMBOL (IC_RESULT (ic))->rematiCode = ic;
2262 OP_SYMBOL (IC_RESULT (ic))->usl.spillLoc = NULL;
2266 /* if straight assignment then carry remat flag if
2267 this is the only definition */
2268 if (ic->op == '=' &&
2269 !POINTER_SET (ic) &&
2270 IS_SYMOP (IC_RIGHT (ic)) &&
2271 OP_SYMBOL (IC_RIGHT (ic))->remat &&
2272 bitVectnBitsOn (OP_SYMBOL (IC_RESULT (ic))->defs) <= 1)
2275 OP_SYMBOL (IC_RESULT (ic))->remat =
2276 OP_SYMBOL (IC_RIGHT (ic))->remat;
2277 OP_SYMBOL (IC_RESULT (ic))->rematiCode =
2278 OP_SYMBOL (IC_RIGHT (ic))->rematiCode;
2281 /* if this is a +/- operation with a rematerizable
2282 then mark this as rematerializable as well */
2283 if ((ic->op == '+' || ic->op == '-') &&
2284 (IS_SYMOP (IC_LEFT (ic)) &&
2285 IS_ITEMP (IC_RESULT (ic)) &&
2286 OP_SYMBOL (IC_LEFT (ic))->remat &&
2287 bitVectnBitsOn (OP_DEFS (IC_RESULT (ic))) == 1 &&
2288 IS_OP_LITERAL (IC_RIGHT (ic))))
2290 OP_SYMBOL (IC_RESULT (ic))->remat = 1;
2291 OP_SYMBOL (IC_RESULT (ic))->rematiCode = ic;
2292 OP_SYMBOL (IC_RESULT (ic))->usl.spillLoc = NULL;
2295 /* mark the pointer usages */
2296 if (POINTER_SET (ic))
2297 OP_SYMBOL (IC_RESULT (ic))->uptr = 1;
2299 if (POINTER_GET (ic))
2300 OP_SYMBOL (IC_LEFT (ic))->uptr = 1;
2304 /* if we are using a symbol on the stack
2305 then we should say mcs51_ptrRegReq */
2306 if (ic->op == IFX && IS_SYMOP (IC_COND (ic)))
2307 mcs51_ptrRegReq += ((OP_SYMBOL (IC_COND (ic))->onStack ||
2308 OP_SYMBOL (IC_COND (ic))->iaccess) ? 1 : 0);
2309 else if (ic->op == JUMPTABLE && IS_SYMOP (IC_JTCOND (ic)))
2310 mcs51_ptrRegReq += ((OP_SYMBOL (IC_JTCOND (ic))->onStack ||
2311 OP_SYMBOL (IC_JTCOND (ic))->iaccess) ? 1 : 0);
2314 if (IS_SYMOP (IC_LEFT (ic)))
2315 mcs51_ptrRegReq += ((OP_SYMBOL (IC_LEFT (ic))->onStack ||
2316 OP_SYMBOL (IC_LEFT (ic))->iaccess) ? 1 : 0);
2317 if (IS_SYMOP (IC_RIGHT (ic)))
2318 mcs51_ptrRegReq += ((OP_SYMBOL (IC_RIGHT (ic))->onStack ||
2319 OP_SYMBOL (IC_RIGHT (ic))->iaccess) ? 1 : 0);
2320 if (IS_SYMOP (IC_RESULT (ic)))
2321 mcs51_ptrRegReq += ((OP_SYMBOL (IC_RESULT (ic))->onStack ||
2322 OP_SYMBOL (IC_RESULT (ic))->iaccess) ? 1 : 0);
2326 /* if the condition of an if instruction
2327 is defined in the previous instruction then
2328 mark the itemp as a conditional */
2329 if ((IS_CONDITIONAL (ic) ||
2330 (IS_BITWISE_OP(ic) && isBitwiseOptimizable (ic))) &&
2331 ic->next && ic->next->op == IFX &&
2332 isOperandEqual (IC_RESULT (ic), IC_COND (ic->next)) &&
2333 OP_SYMBOL (IC_RESULT (ic))->liveTo <= ic->next->seq)
2335 OP_SYMBOL (IC_RESULT (ic))->regType = REG_CND;
2339 /* reduce for support function calls */
2340 if (ic->supportRtn || ic->op == '+' || ic->op == '-')
2341 packRegsForSupport (ic, ebp);
2343 /* some cases the redundant moves can
2344 can be eliminated for return statements */
2345 if ((ic->op == RETURN || ic->op == SEND) &&
2346 !isOperandInFarSpace (IC_LEFT (ic)) &&
2347 options.model == MODEL_SMALL) {
2348 if (0 && options.stackAuto) {
2349 /* we should check here if acc will be clobbered for stack
2350 offset calculations */
2352 packRegsForOneuse (ic, IC_LEFT (ic), ebp);
2356 /* if pointer set & left has a size more than
2357 one and right is not in far space */
2358 if (POINTER_SET (ic) &&
2359 !isOperandInFarSpace (IC_RIGHT (ic)) &&
2360 !OP_SYMBOL (IC_RESULT (ic))->remat &&
2361 !IS_OP_RUONLY (IC_RIGHT (ic)) &&
2362 getSize (aggrToPtr (operandType (IC_RESULT (ic)), FALSE)) > 1)
2364 packRegsForOneuse (ic, IC_RESULT (ic), ebp);
2366 /* if pointer get */
2367 if (POINTER_GET (ic) &&
2368 !isOperandInFarSpace (IC_RESULT (ic)) &&
2369 !OP_SYMBOL (IC_LEFT (ic))->remat &&
2370 !IS_OP_RUONLY (IC_RESULT (ic)) &&
2371 getSize (aggrToPtr (operandType (IC_LEFT (ic)), FALSE)) > 1)
2373 packRegsForOneuse (ic, IC_LEFT (ic), ebp);
2376 /* if this is cast for intergral promotion then
2377 check if only use of the definition of the
2378 operand being casted/ if yes then replace
2379 the result of that arithmetic operation with
2380 this result and get rid of the cast */
2383 sym_link *fromType = operandType (IC_RIGHT (ic));
2384 sym_link *toType = operandType (IC_LEFT (ic));
2386 if (IS_INTEGRAL (fromType) && IS_INTEGRAL (toType) &&
2387 getSize (fromType) != getSize (toType) &&
2388 SPEC_USIGN (fromType) == SPEC_USIGN (toType))
2391 iCode *dic = packRegsForOneuse (ic, IC_RIGHT (ic), ebp);
2394 if (IS_ARITHMETIC_OP (dic))
2396 IC_RESULT (dic) = IC_RESULT (ic);
2397 remiCodeFromeBBlock (ebp, ic);
2398 hTabDeleteItem (&iCodehTab, ic->key, ic, DELETE_ITEM, NULL);
2399 OP_DEFS (IC_RESULT (dic)) = bitVectSetBit (OP_DEFS (IC_RESULT (dic)), dic->key);
2403 OP_SYMBOL (IC_RIGHT (ic))->ruonly = 0;
2409 /* if the type from and type to are the same
2410 then if this is the only use then packit */
2411 if (checkType (operandType (IC_RIGHT (ic)),
2412 operandType (IC_LEFT (ic))) == 1)
2414 iCode *dic = packRegsForOneuse (ic, IC_RIGHT (ic), ebp);
2417 IC_RESULT (dic) = IC_RESULT (ic);
2418 remiCodeFromeBBlock (ebp, ic);
2419 hTabDeleteItem (&iCodehTab, ic->key, ic, DELETE_ITEM, NULL);
2420 OP_DEFS (IC_RESULT (dic)) = bitVectSetBit (OP_DEFS (IC_RESULT (dic)), dic->key);
2428 iTempNN := (some variable in farspace) V1
2433 if (ic->op == IPUSH)
2435 packForPush (ic, ebp);
2439 /* pack registers for accumulator use, when the
2440 result of an arithmetic or bit wise operation
2441 has only one use, that use is immediately following
2442 the defintion and the using iCode has only one
2443 operand or has two operands but one is literal &
2444 the result of that operation is not on stack then
2445 we can leave the result of this operation in acc:b
2447 if ((IS_ARITHMETIC_OP (ic)
2448 || IS_BITWISE_OP (ic)
2449 || ic->op == LEFT_OP || ic->op == RIGHT_OP
2450 || (ic->op == ADDRESS_OF && isOperandOnStack (IC_LEFT (ic)))
2452 IS_ITEMP (IC_RESULT (ic)) &&
2453 getSize (operandType (IC_RESULT (ic))) <= 2)
2455 packRegsForAccUse (ic);
2459 /*-----------------------------------------------------------------*/
2460 /* assignRegisters - assigns registers to each live range as need */
2461 /*-----------------------------------------------------------------*/
2463 mcs51_assignRegisters (eBBlock ** ebbs, int count)
2468 setToNull ((void *) &_G.funcrUsed);
2469 mcs51_ptrRegReq = _G.stackExtend = _G.dataExtend = 0;
2470 /* if not register extentions then reduce number
2472 if (options.regExtend)
2477 /* change assignments this will remove some
2478 live ranges reducing some register pressure */
2479 for (i = 0; i < count; i++)
2480 packRegisters (ebbs[i]);
2482 if (options.dump_pack)
2483 dumpEbbsToFileExt (".dumppack", ebbs, count);
2485 /* first determine for each live range the number of
2486 registers & the type of registers required for each */
2489 /* and serially allocate registers */
2490 serialRegAssign (ebbs, count);
2492 /* if stack was extended then tell the user */
2495 /* werror(W_TOOMANY_SPILS,"stack", */
2496 /* _G.stackExtend,currFunc->name,""); */
2502 /* werror(W_TOOMANY_SPILS,"data space", */
2503 /* _G.dataExtend,currFunc->name,""); */
2507 /* after that create the register mask
2508 for each of the instruction */
2509 createRegMask (ebbs, count);
2511 /* redo that offsets for stacked automatic variables */
2512 redoStackOffsets ();
2514 if (options.dump_rassgn)
2516 dumpEbbsToFileExt (".dumprassgn", ebbs, count);
2517 dumpLiveRanges (".dumplrange", liveRanges);
2520 /* do the overlaysegment stuff SDCCmem.c */
2521 doOverlays (ebbs, count);
2523 /* now get back the chain */
2524 ic = iCodeLabelOptimize (iCodeFromeBBlock (ebbs, count));
2529 /* free up any _G.stackSpil locations allocated */
2530 applyToSet (_G.stackSpil, deallocStackSpil);
2532 setToNull ((void **) &_G.stackSpil);
2533 setToNull ((void **) &_G.spiltSet);
2534 /* mark all registers as free */