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)
1181 <= (unsigned int) PTRSIZE)
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)
1626 #if 0 // jwk 20010410
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))
1637 /* if there is a function call then don't pack it */
1638 if ((dic->op == CALL || dic->op == PCALL))
1648 if (IS_TRUE_SYMOP (IC_RESULT (dic)) &&
1649 IS_OP_VOLATILE (IC_RESULT (dic)))
1655 if (IS_SYMOP (IC_RESULT (dic)) &&
1656 IC_RESULT (dic)->key == IC_RIGHT (ic)->key)
1658 if (POINTER_SET (dic))
1664 if (IS_SYMOP (IC_RIGHT (dic)) &&
1665 (IC_RIGHT (dic)->key == IC_RESULT (ic)->key ||
1666 IC_RIGHT (dic)->key == IC_RIGHT (ic)->key))
1672 if (IS_SYMOP (IC_LEFT (dic)) &&
1673 (IC_LEFT (dic)->key == IC_RESULT (ic)->key ||
1674 IC_LEFT (dic)->key == IC_RIGHT (ic)->key))
1680 if (POINTER_SET (dic) &&
1681 IC_RESULT (dic)->key == IC_RESULT (ic)->key)
1689 return 0; /* did not find */
1691 /* if assignment then check that right is not a bit */
1692 if (ASSIGNMENT (dic) && !POINTER_SET (dic))
1694 sym_link *etype = operandType (IC_RIGHT (dic));
1695 if (IS_BITFIELD (etype))
1698 /* if the result is on stack or iaccess then it must be
1699 the same atleast one of the operands */
1700 if (OP_SYMBOL (IC_RESULT (ic))->onStack ||
1701 OP_SYMBOL (IC_RESULT (ic))->iaccess)
1704 /* the operation has only one symbol
1705 operator then we can pack */
1706 if ((IC_LEFT (dic) && !IS_SYMOP (IC_LEFT (dic))) ||
1707 (IC_RIGHT (dic) && !IS_SYMOP (IC_RIGHT (dic))))
1710 if (!((IC_LEFT (dic) &&
1711 IC_RESULT (ic)->key == IC_LEFT (dic)->key) ||
1713 IC_RESULT (ic)->key == IC_RIGHT (dic)->key)))
1717 /* found the definition */
1718 /* replace the result with the result of */
1719 /* this assignment and remove this assignment */
1720 IC_RESULT (dic) = IC_RESULT (ic);
1722 if (IS_ITEMP (IC_RESULT (dic)) && OP_SYMBOL (IC_RESULT (dic))->liveFrom > dic->seq)
1724 OP_SYMBOL (IC_RESULT (dic))->liveFrom = dic->seq;
1726 /* delete from liverange table also
1727 delete from all the points inbetween and the new
1729 for (sic = dic; sic != ic; sic = sic->next)
1731 bitVectUnSetBit (sic->rlive, IC_RESULT (ic)->key);
1732 if (IS_ITEMP (IC_RESULT (dic)))
1733 bitVectSetBit (sic->rlive, IC_RESULT (dic)->key);
1736 remiCodeFromeBBlock (ebp, ic);
1737 hTabDeleteItem (&iCodehTab, ic->key, ic, DELETE_ITEM, NULL);
1738 OP_DEFS (IC_RESULT (dic)) = bitVectSetBit (OP_DEFS (IC_RESULT (dic)), dic->key);
1743 /*-----------------------------------------------------------------*/
1744 /* findAssignToSym : scanning backwards looks for first assig found */
1745 /*-----------------------------------------------------------------*/
1747 findAssignToSym (operand * op, iCode * ic)
1751 for (dic = ic->prev; dic; dic = dic->prev)
1754 /* if definition by assignment */
1755 if (dic->op == '=' &&
1756 !POINTER_SET (dic) &&
1757 IC_RESULT (dic)->key == op->key
1758 /* && IS_TRUE_SYMOP(IC_RIGHT(dic)) */
1762 /* we are interested only if defined in far space */
1763 /* or in stack space in case of + & - */
1765 /* if assigned to a non-symbol then return
1767 if (!IS_SYMOP (IC_RIGHT (dic)))
1770 /* if the symbol is in far space then
1772 if (isOperandInFarSpace (IC_RIGHT (dic)))
1775 /* for + & - operations make sure that
1776 if it is on the stack it is the same
1777 as one of the three operands */
1778 if ((ic->op == '+' || ic->op == '-') &&
1779 OP_SYMBOL (IC_RIGHT (dic))->onStack)
1782 if (IC_RESULT (ic)->key != IC_RIGHT (dic)->key &&
1783 IC_LEFT (ic)->key != IC_RIGHT (dic)->key &&
1784 IC_RIGHT (ic)->key != IC_RIGHT (dic)->key)
1792 /* if we find an usage then we cannot delete it */
1793 if (IC_LEFT (dic) && IC_LEFT (dic)->key == op->key)
1796 if (IC_RIGHT (dic) && IC_RIGHT (dic)->key == op->key)
1799 if (POINTER_SET (dic) && IC_RESULT (dic)->key == op->key)
1803 /* now make sure that the right side of dic
1804 is not defined between ic & dic */
1807 iCode *sic = dic->next;
1809 for (; sic != ic; sic = sic->next)
1810 if (IC_RESULT (sic) &&
1811 IC_RESULT (sic)->key == IC_RIGHT (dic)->key)
1820 /*-----------------------------------------------------------------*/
1821 /* packRegsForSupport :- reduce some registers for support calls */
1822 /*-----------------------------------------------------------------*/
1824 packRegsForSupport (iCode * ic, eBBlock * ebp)
1827 /* for the left & right operand :- look to see if the
1828 left was assigned a true symbol in far space in that
1829 case replace them */
1831 if (IS_ITEMP (IC_LEFT (ic)) &&
1832 OP_SYMBOL (IC_LEFT (ic))->liveTo <= ic->seq)
1834 iCode *dic = findAssignToSym (IC_LEFT (ic), ic);
1840 /* found it we need to remove it from the
1842 for (sic = dic; sic != ic; sic = sic->next)
1843 bitVectUnSetBit (sic->rlive, IC_LEFT (ic)->key);
1845 IC_LEFT (ic)->operand.symOperand =
1846 IC_RIGHT (dic)->operand.symOperand;
1847 IC_LEFT (ic)->key = IC_RIGHT (dic)->operand.symOperand->key;
1848 remiCodeFromeBBlock (ebp, dic);
1849 hTabDeleteItem (&iCodehTab, dic->key, dic, DELETE_ITEM, NULL);
1853 /* do the same for the right operand */
1856 IS_ITEMP (IC_RIGHT (ic)) &&
1857 OP_SYMBOL (IC_RIGHT (ic))->liveTo <= ic->seq)
1859 iCode *dic = findAssignToSym (IC_RIGHT (ic), ic);
1865 /* if this is a subtraction & the result
1866 is a true symbol in far space then don't pack */
1867 if (ic->op == '-' && IS_TRUE_SYMOP (IC_RESULT (dic)))
1869 sym_link *etype = getSpec (operandType (IC_RESULT (dic)));
1870 if (IN_FARSPACE (SPEC_OCLS (etype)))
1873 /* found it we need to remove it from the
1875 for (sic = dic; sic != ic; sic = sic->next)
1876 bitVectUnSetBit (sic->rlive, IC_RIGHT (ic)->key);
1878 IC_RIGHT (ic)->operand.symOperand =
1879 IC_RIGHT (dic)->operand.symOperand;
1880 IC_RIGHT (ic)->key = IC_RIGHT (dic)->operand.symOperand->key;
1882 remiCodeFromeBBlock (ebp, dic);
1883 hTabDeleteItem (&iCodehTab, dic->key, dic, DELETE_ITEM, NULL);
1890 #define IS_OP_RUONLY(x) (x && IS_SYMOP(x) && OP_SYMBOL(x)->ruonly)
1893 /*-----------------------------------------------------------------*/
1894 /* packRegsForOneuse : - will reduce some registers for single Use */
1895 /*-----------------------------------------------------------------*/
1897 packRegsForOneuse (iCode * ic, operand * op, eBBlock * ebp)
1902 /* if returning a literal then do nothing */
1906 /* only upto 2 bytes since we cannot predict
1907 the usage of b, & acc */
1908 if (getSize (operandType (op)) > (fReturnSizeMCS51 - 2) &&
1911 !POINTER_SET (ic) &&
1915 /* this routine will mark the a symbol as used in one
1916 instruction use only && if the defintion is local
1917 (ie. within the basic block) && has only one definition &&
1918 that definiion is either a return value from a
1919 function or does not contain any variables in
1921 uses = bitVectCopy (OP_USES (op));
1922 bitVectUnSetBit (uses, ic->key); /* take away this iCode */
1923 if (!bitVectIsZero (uses)) /* has other uses */
1926 /* if it has only one defintion */
1927 if (bitVectnBitsOn (OP_DEFS (op)) > 1)
1928 return NULL; /* has more than one definition */
1930 /* get that definition */
1932 hTabItemWithKey (iCodehTab,
1933 bitVectFirstBit (OP_DEFS (op)))))
1936 /* found the definition now check if it is local */
1937 if (dic->seq < ebp->fSeq ||
1938 dic->seq > ebp->lSeq)
1939 return NULL; /* non-local */
1941 /* now check if it is the return from
1943 if (dic->op == CALL || dic->op == PCALL)
1945 if (ic->op != SEND && ic->op != RETURN)
1947 OP_SYMBOL (op)->ruonly = 1;
1954 /* otherwise check that the definition does
1955 not contain any symbols in far space */
1956 if (isOperandInFarSpace (IC_LEFT (dic)) ||
1957 isOperandInFarSpace (IC_RIGHT (dic)) ||
1958 IS_OP_RUONLY (IC_LEFT (ic)) ||
1959 IS_OP_RUONLY (IC_RIGHT (ic)))
1964 /* if pointer set then make sure the pointer
1966 if (POINTER_SET (dic) &&
1967 !IS_DATA_PTR (aggrToPtr (operandType (IC_RESULT (dic)), FALSE)))
1970 if (POINTER_GET (dic) &&
1971 !IS_DATA_PTR (aggrToPtr (operandType (IC_LEFT (dic)), FALSE)))
1976 /* also make sure the intervenening instructions
1977 don't have any thing in far space */
1978 for (dic = dic->next; dic && dic != ic && sic != ic; dic = dic->next)
1981 /* if there is an intervening function call then no */
1982 if (dic->op == CALL || dic->op == PCALL)
1984 /* if pointer set then make sure the pointer
1986 if (POINTER_SET (dic) &&
1987 !IS_DATA_PTR (aggrToPtr (operandType (IC_RESULT (dic)), FALSE)))
1990 if (POINTER_GET (dic) &&
1991 !IS_DATA_PTR (aggrToPtr (operandType (IC_LEFT (dic)), FALSE)))
1994 /* if address of & the result is remat the okay */
1995 if (dic->op == ADDRESS_OF &&
1996 OP_SYMBOL (IC_RESULT (dic))->remat)
1999 /* if operand has size of three or more & this
2000 operation is a '*','/' or '%' then 'b' may
2002 if ((dic->op == '%' || dic->op == '/' || dic->op == '*') &&
2003 getSize (operandType (op)) >= 3)
2006 /* if left or right or result is in far space */
2007 if (isOperandInFarSpace (IC_LEFT (dic)) ||
2008 isOperandInFarSpace (IC_RIGHT (dic)) ||
2009 isOperandInFarSpace (IC_RESULT (dic)) ||
2010 IS_OP_RUONLY (IC_LEFT (dic)) ||
2011 IS_OP_RUONLY (IC_RIGHT (dic)) ||
2012 IS_OP_RUONLY (IC_RESULT (dic)))
2016 /* if left or right or result is on stack */
2017 if (isOperandOnStack(IC_LEFT(dic)) ||
2018 isOperandOnStack(IC_RIGHT(dic)) ||
2019 isOperandOnStack(IC_RESULT(dic))) {
2024 OP_SYMBOL (op)->ruonly = 1;
2029 /*-----------------------------------------------------------------*/
2030 /* isBitwiseOptimizable - requirements of JEAN LOUIS VERN */
2031 /*-----------------------------------------------------------------*/
2033 isBitwiseOptimizable (iCode * ic)
2035 sym_link *ltype = getSpec (operandType (IC_LEFT (ic)));
2036 sym_link *rtype = getSpec (operandType (IC_RIGHT (ic)));
2038 /* bitwise operations are considered optimizable
2039 under the following conditions (Jean-Louis VERN)
2051 if (IS_LITERAL(rtype) ||
2052 (IS_BITVAR (ltype) && IN_BITSPACE (SPEC_OCLS (ltype))))
2058 /*-----------------------------------------------------------------*/
2059 /* packRegsForAccUse - pack registers for acc use */
2060 /*-----------------------------------------------------------------*/
2062 packRegsForAccUse (iCode * ic)
2066 /* if + or - then it has to be one byte result */
2067 if ((ic->op == '+' || ic->op == '-')
2068 && getSize (operandType (IC_RESULT (ic))) > 1)
2071 /* if shift operation make sure right side is not a literal */
2072 if (ic->op == RIGHT_OP &&
2073 (isOperandLiteral (IC_RIGHT (ic)) ||
2074 getSize (operandType (IC_RESULT (ic))) > 1))
2077 if (ic->op == LEFT_OP &&
2078 (isOperandLiteral (IC_RIGHT (ic)) ||
2079 getSize (operandType (IC_RESULT (ic))) > 1))
2082 if (IS_BITWISE_OP (ic) &&
2083 getSize (operandType (IC_RESULT (ic))) > 1)
2087 /* has only one definition */
2088 if (bitVectnBitsOn (OP_DEFS (IC_RESULT (ic))) > 1)
2091 /* has only one use */
2092 if (bitVectnBitsOn (OP_USES (IC_RESULT (ic))) > 1)
2095 /* and the usage immediately follows this iCode */
2096 if (!(uic = hTabItemWithKey (iCodehTab,
2097 bitVectFirstBit (OP_USES (IC_RESULT (ic))))))
2100 if (ic->next != uic)
2103 /* if it is a conditional branch then we definitely can */
2107 if (uic->op == JUMPTABLE)
2110 /* if the usage is not is an assignment
2111 or an arithmetic / bitwise / shift operation then not */
2112 if (POINTER_SET (uic) &&
2113 getSize (aggrToPtr (operandType (IC_RESULT (uic)), FALSE)) > 1)
2116 if (uic->op != '=' &&
2117 !IS_ARITHMETIC_OP (uic) &&
2118 !IS_BITWISE_OP (uic) &&
2119 uic->op != LEFT_OP &&
2120 uic->op != RIGHT_OP)
2123 /* if used in ^ operation then make sure right is not a
2125 if (uic->op == '^' && isOperandLiteral (IC_RIGHT (uic)))
2128 /* if shift operation make sure right side is not a literal */
2129 if (uic->op == RIGHT_OP &&
2130 (isOperandLiteral (IC_RIGHT (uic)) ||
2131 getSize (operandType (IC_RESULT (uic))) > 1))
2134 if (uic->op == LEFT_OP &&
2135 (isOperandLiteral (IC_RIGHT (uic)) ||
2136 getSize (operandType (IC_RESULT (uic))) > 1))
2139 /* make sure that the result of this icode is not on the
2140 stack, since acc is used to compute stack offset */
2141 if (IS_TRUE_SYMOP (IC_RESULT (uic)) &&
2142 OP_SYMBOL (IC_RESULT (uic))->onStack)
2145 /* if either one of them in far space then we cannot */
2146 if ((IS_TRUE_SYMOP (IC_LEFT (uic)) &&
2147 isOperandInFarSpace (IC_LEFT (uic))) ||
2148 (IS_TRUE_SYMOP (IC_RIGHT (uic)) &&
2149 isOperandInFarSpace (IC_RIGHT (uic))))
2152 /* if the usage has only one operand then we can */
2153 if (IC_LEFT (uic) == NULL ||
2154 IC_RIGHT (uic) == NULL)
2157 /* make sure this is on the left side if not
2158 a '+' since '+' is commutative */
2159 if (ic->op != '+' &&
2160 IC_LEFT (uic)->key != IC_RESULT (ic)->key)
2163 /* if one of them is a literal then we can */
2164 if ((IC_LEFT (uic) && IS_OP_LITERAL (IC_LEFT (uic))) ||
2165 (IC_RIGHT (uic) && IS_OP_LITERAL (IC_RIGHT (uic))))
2167 OP_SYMBOL (IC_RESULT (ic))->accuse = 1;
2171 /* if the other one is not on stack then we can */
2172 if (IC_LEFT (uic)->key == IC_RESULT (ic)->key &&
2173 (IS_ITEMP (IC_RIGHT (uic)) ||
2174 (IS_TRUE_SYMOP (IC_RIGHT (uic)) &&
2175 !OP_SYMBOL (IC_RIGHT (uic))->onStack)))
2178 if (IC_RIGHT (uic)->key == IC_RESULT (ic)->key &&
2179 (IS_ITEMP (IC_LEFT (uic)) ||
2180 (IS_TRUE_SYMOP (IC_LEFT (uic)) &&
2181 !OP_SYMBOL (IC_LEFT (uic))->onStack)))
2187 OP_SYMBOL (IC_RESULT (ic))->accuse = 1;
2192 /*-----------------------------------------------------------------*/
2193 /* packForPush - hueristics to reduce iCode for pushing */
2194 /*-----------------------------------------------------------------*/
2196 packForPush (iCode * ic, eBBlock * ebp)
2201 if (ic->op != IPUSH || !IS_ITEMP (IC_LEFT (ic)))
2204 /* must have only definition & one usage */
2205 if (bitVectnBitsOn (OP_DEFS (IC_LEFT (ic))) != 1 ||
2206 bitVectnBitsOn (OP_USES (IC_LEFT (ic))) != 1)
2209 /* find the definition */
2210 if (!(dic = hTabItemWithKey (iCodehTab,
2211 bitVectFirstBit (OP_DEFS (IC_LEFT (ic))))))
2214 if (dic->op != '=' || POINTER_SET (dic))
2217 /* make sure the right side does not have any definitions
2219 dbv = OP_DEFS(IC_RIGHT(dic));
2220 for (lic = ic; lic && lic != dic ; lic = lic->prev) {
2221 if (bitVectBitValue(dbv,lic->key))
2224 /* we now we know that it has one & only one def & use
2225 and the that the definition is an assignment */
2226 IC_LEFT (ic) = IC_RIGHT (dic);
2228 remiCodeFromeBBlock (ebp, dic);
2229 hTabDeleteItem (&iCodehTab, dic->key, dic, DELETE_ITEM, NULL);
2232 /*-----------------------------------------------------------------*/
2233 /* packRegisters - does some transformations to reduce register */
2235 /*-----------------------------------------------------------------*/
2237 packRegisters (eBBlock * ebp)
2247 /* look for assignments of the form */
2248 /* iTempNN = TRueSym (someoperation) SomeOperand */
2250 /* TrueSym := iTempNN:1 */
2251 for (ic = ebp->sch; ic; ic = ic->next)
2253 /* find assignment of the form TrueSym := iTempNN:1 */
2254 if (ic->op == '=' && !POINTER_SET (ic))
2255 change += packRegsForAssign (ic, ebp);
2262 for (ic = ebp->sch; ic; ic = ic->next)
2264 /* if this is an itemp & result of a address of a true sym
2265 then mark this as rematerialisable */
2266 if (ic->op == ADDRESS_OF &&
2267 IS_ITEMP (IC_RESULT (ic)) &&
2268 IS_TRUE_SYMOP (IC_LEFT (ic)) &&
2269 bitVectnBitsOn (OP_DEFS (IC_RESULT (ic))) == 1 &&
2270 !OP_SYMBOL (IC_LEFT (ic))->onStack)
2273 OP_SYMBOL (IC_RESULT (ic))->remat = 1;
2274 OP_SYMBOL (IC_RESULT (ic))->rematiCode = ic;
2275 OP_SYMBOL (IC_RESULT (ic))->usl.spillLoc = NULL;
2279 /* if straight assignment then carry remat flag if
2280 this is the only definition */
2281 if (ic->op == '=' &&
2282 !POINTER_SET (ic) &&
2283 IS_SYMOP (IC_RIGHT (ic)) &&
2284 OP_SYMBOL (IC_RIGHT (ic))->remat &&
2285 bitVectnBitsOn (OP_SYMBOL (IC_RESULT (ic))->defs) <= 1)
2288 OP_SYMBOL (IC_RESULT (ic))->remat =
2289 OP_SYMBOL (IC_RIGHT (ic))->remat;
2290 OP_SYMBOL (IC_RESULT (ic))->rematiCode =
2291 OP_SYMBOL (IC_RIGHT (ic))->rematiCode;
2294 /* if this is a +/- operation with a rematerizable
2295 then mark this as rematerializable as well */
2296 if ((ic->op == '+' || ic->op == '-') &&
2297 (IS_SYMOP (IC_LEFT (ic)) &&
2298 IS_ITEMP (IC_RESULT (ic)) &&
2299 OP_SYMBOL (IC_LEFT (ic))->remat &&
2300 bitVectnBitsOn (OP_DEFS (IC_RESULT (ic))) == 1 &&
2301 IS_OP_LITERAL (IC_RIGHT (ic))))
2303 OP_SYMBOL (IC_RESULT (ic))->remat = 1;
2304 OP_SYMBOL (IC_RESULT (ic))->rematiCode = ic;
2305 OP_SYMBOL (IC_RESULT (ic))->usl.spillLoc = NULL;
2308 /* mark the pointer usages */
2309 if (POINTER_SET (ic))
2310 OP_SYMBOL (IC_RESULT (ic))->uptr = 1;
2312 if (POINTER_GET (ic))
2313 OP_SYMBOL (IC_LEFT (ic))->uptr = 1;
2317 /* if we are using a symbol on the stack
2318 then we should say mcs51_ptrRegReq */
2319 if (ic->op == IFX && IS_SYMOP (IC_COND (ic)))
2320 mcs51_ptrRegReq += ((OP_SYMBOL (IC_COND (ic))->onStack ||
2321 OP_SYMBOL (IC_COND (ic))->iaccess) ? 1 : 0);
2322 else if (ic->op == JUMPTABLE && IS_SYMOP (IC_JTCOND (ic)))
2323 mcs51_ptrRegReq += ((OP_SYMBOL (IC_JTCOND (ic))->onStack ||
2324 OP_SYMBOL (IC_JTCOND (ic))->iaccess) ? 1 : 0);
2327 if (IS_SYMOP (IC_LEFT (ic)))
2328 mcs51_ptrRegReq += ((OP_SYMBOL (IC_LEFT (ic))->onStack ||
2329 OP_SYMBOL (IC_LEFT (ic))->iaccess) ? 1 : 0);
2330 if (IS_SYMOP (IC_RIGHT (ic)))
2331 mcs51_ptrRegReq += ((OP_SYMBOL (IC_RIGHT (ic))->onStack ||
2332 OP_SYMBOL (IC_RIGHT (ic))->iaccess) ? 1 : 0);
2333 if (IS_SYMOP (IC_RESULT (ic)))
2334 mcs51_ptrRegReq += ((OP_SYMBOL (IC_RESULT (ic))->onStack ||
2335 OP_SYMBOL (IC_RESULT (ic))->iaccess) ? 1 : 0);
2340 /* if the condition of an if instruction
2341 is defined in the previous instruction then
2342 mark the itemp as a conditional */
2343 if ((IS_CONDITIONAL (ic) ||
2344 (IS_BITWISE_OP(ic) && isBitwiseOptimizable (ic))) &&
2345 ic->next && ic->next->op == IFX &&
2346 isOperandEqual (IC_RESULT (ic), IC_COND (ic->next)) &&
2347 OP_SYMBOL (IC_RESULT (ic))->liveTo <= ic->next->seq)
2349 OP_SYMBOL (IC_RESULT (ic))->regType = REG_CND;
2353 /* if the condition of an if instruction
2354 is defined in the previous instruction and
2355 this is the only usage then
2356 mark the itemp as a conditional */
2357 if ((IS_CONDITIONAL (ic) ||
2358 (IS_BITWISE_OP(ic) && isBitwiseOptimizable (ic))) &&
2359 ic->next && ic->next->op == IFX &&
2360 bitVectnBitsOn (OP_USES(IC_RESULT(ic)))==1 &&
2361 isOperandEqual (IC_RESULT (ic), IC_COND (ic->next)) &&
2362 OP_SYMBOL (IC_RESULT (ic))->liveTo <= ic->next->seq)
2364 OP_SYMBOL (IC_RESULT (ic))->regType = REG_CND;
2369 /* reduce for support function calls */
2370 if (ic->supportRtn || ic->op == '+' || ic->op == '-')
2371 packRegsForSupport (ic, ebp);
2373 /* some cases the redundant moves can
2374 can be eliminated for return statements */
2375 if ((ic->op == RETURN || ic->op == SEND) &&
2376 !isOperandInFarSpace (IC_LEFT (ic)) &&
2377 options.model == MODEL_SMALL) {
2378 if (0 && options.stackAuto) {
2379 /* we should check here if acc will be clobbered for stack
2380 offset calculations */
2382 packRegsForOneuse (ic, IC_LEFT (ic), ebp);
2386 /* if pointer set & left has a size more than
2387 one and right is not in far space */
2388 if (POINTER_SET (ic) &&
2389 !isOperandInFarSpace (IC_RIGHT (ic)) &&
2390 !OP_SYMBOL (IC_RESULT (ic))->remat &&
2391 !IS_OP_RUONLY (IC_RIGHT (ic)) &&
2392 getSize (aggrToPtr (operandType (IC_RESULT (ic)), FALSE)) > 1)
2394 packRegsForOneuse (ic, IC_RESULT (ic), ebp);
2396 /* if pointer get */
2397 if (POINTER_GET (ic) &&
2398 !isOperandInFarSpace (IC_RESULT (ic)) &&
2399 !OP_SYMBOL (IC_LEFT (ic))->remat &&
2400 !IS_OP_RUONLY (IC_RESULT (ic)) &&
2401 getSize (aggrToPtr (operandType (IC_LEFT (ic)), FALSE)) > 1)
2403 packRegsForOneuse (ic, IC_LEFT (ic), ebp);
2406 /* if this is cast for intergral promotion then
2407 check if only use of the definition of the
2408 operand being casted/ if yes then replace
2409 the result of that arithmetic operation with
2410 this result and get rid of the cast */
2413 sym_link *fromType = operandType (IC_RIGHT (ic));
2414 sym_link *toType = operandType (IC_LEFT (ic));
2416 if (IS_INTEGRAL (fromType) && IS_INTEGRAL (toType) &&
2417 getSize (fromType) != getSize (toType) &&
2418 SPEC_USIGN (fromType) == SPEC_USIGN (toType))
2421 iCode *dic = packRegsForOneuse (ic, IC_RIGHT (ic), ebp);
2424 if (IS_ARITHMETIC_OP (dic))
2426 IC_RESULT (dic) = IC_RESULT (ic);
2427 remiCodeFromeBBlock (ebp, ic);
2428 hTabDeleteItem (&iCodehTab, ic->key, ic, DELETE_ITEM, NULL);
2429 OP_DEFS (IC_RESULT (dic)) = bitVectSetBit (OP_DEFS (IC_RESULT (dic)), dic->key);
2433 OP_SYMBOL (IC_RIGHT (ic))->ruonly = 0;
2439 /* if the type from and type to are the same
2440 then if this is the only use then packit */
2441 if (checkType (operandType (IC_RIGHT (ic)),
2442 operandType (IC_LEFT (ic))) == 1)
2444 iCode *dic = packRegsForOneuse (ic, IC_RIGHT (ic), ebp);
2447 IC_RESULT (dic) = IC_RESULT (ic);
2448 remiCodeFromeBBlock (ebp, ic);
2449 hTabDeleteItem (&iCodehTab, ic->key, ic, DELETE_ITEM, NULL);
2450 OP_DEFS (IC_RESULT (dic)) = bitVectSetBit (OP_DEFS (IC_RESULT (dic)), dic->key);
2458 iTempNN := (some variable in farspace) V1
2463 if (ic->op == IPUSH)
2465 packForPush (ic, ebp);
2469 /* pack registers for accumulator use, when the
2470 result of an arithmetic or bit wise operation
2471 has only one use, that use is immediately following
2472 the defintion and the using iCode has only one
2473 operand or has two operands but one is literal &
2474 the result of that operation is not on stack then
2475 we can leave the result of this operation in acc:b
2477 if ((IS_ARITHMETIC_OP (ic)
2478 || IS_BITWISE_OP (ic)
2479 || ic->op == LEFT_OP || ic->op == RIGHT_OP
2480 || (ic->op == ADDRESS_OF && isOperandOnStack (IC_LEFT (ic)))
2482 IS_ITEMP (IC_RESULT (ic)) &&
2483 getSize (operandType (IC_RESULT (ic))) <= 2)
2485 packRegsForAccUse (ic);
2489 /*-----------------------------------------------------------------*/
2490 /* assignRegisters - assigns registers to each live range as need */
2491 /*-----------------------------------------------------------------*/
2493 mcs51_assignRegisters (eBBlock ** ebbs, int count)
2498 setToNull ((void *) &_G.funcrUsed);
2499 mcs51_ptrRegReq = _G.stackExtend = _G.dataExtend = 0;
2500 /* if not register extentions then reduce number
2502 if (options.regExtend)
2507 /* change assignments this will remove some
2508 live ranges reducing some register pressure */
2509 for (i = 0; i < count; i++)
2510 packRegisters (ebbs[i]);
2512 if (options.dump_pack)
2513 dumpEbbsToFileExt (".dumppack", ebbs, count);
2515 /* first determine for each live range the number of
2516 registers & the type of registers required for each */
2519 /* and serially allocate registers */
2520 serialRegAssign (ebbs, count);
2522 /* if stack was extended then tell the user */
2525 /* werror(W_TOOMANY_SPILS,"stack", */
2526 /* _G.stackExtend,currFunc->name,""); */
2532 /* werror(W_TOOMANY_SPILS,"data space", */
2533 /* _G.dataExtend,currFunc->name,""); */
2537 /* after that create the register mask
2538 for each of the instruction */
2539 createRegMask (ebbs, count);
2541 /* redo that offsets for stacked automatic variables */
2542 redoStackOffsets ();
2544 if (options.dump_rassgn)
2546 dumpEbbsToFileExt (".dumprassgn", ebbs, count);
2547 dumpLiveRanges (".dumplrange", liveRanges);
2550 /* do the overlaysegment stuff SDCCmem.c */
2551 doOverlays (ebbs, count);
2553 /* now get back the chain */
2554 ic = iCodeLabelOptimize (iCodeFromeBBlock (ebbs, count));
2559 /* free up any _G.stackSpil locations allocated */
2560 applyToSet (_G.stackSpil, deallocStackSpil);
2562 setToNull ((void **) &_G.stackSpil);
2563 setToNull ((void **) &_G.spiltSet);
2564 /* mark all registers as free */