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 spilt */
459 /* if it does not overlap with this then
460 not need to spill it */
462 if (lrsym->isspilt || !lrsym->nRegs ||
463 (lrsym->liveTo < forSym->liveFrom))
466 /* go thru the registers : if it is either
467 r0 or r1 then spil it */
468 for (j = 0; j < lrsym->nRegs; j++)
469 if (lrsym->regs[j] == r0 ||
470 lrsym->regs[j] == r1)
479 /*-----------------------------------------------------------------*/
480 /* createStackSpil - create a location on the stack to spil */
481 /*-----------------------------------------------------------------*/
483 createStackSpil (symbol * sym)
486 int useXstack, model;
490 /* first go try and find a free one that is already
491 existing on the stack */
492 if (applyToSet (_G.stackSpil, isFree, &sloc, sym))
494 /* found a free one : just update & return */
495 sym->usl.spillLoc = sloc;
498 addSetHead (&sloc->usl.itmpStack, sym);
502 /* could not then have to create one , this is the hard part
503 we need to allocate this on the stack : this is really a
504 hack!! but cannot think of anything better at this time */
506 if (sprintf (slocBuffer, "sloc%d", _G.slocNum++) >= sizeof (slocBuffer))
508 fprintf (stderr, "***Internal error: slocBuffer overflowed: %s:%d\n",
513 sloc = newiTemp (slocBuffer);
515 /* set the type to the spilling symbol */
516 sloc->type = copyLinkChain (sym->type);
517 sloc->etype = getSpec (sloc->type);
518 SPEC_SCLS (sloc->etype) = S_DATA;
519 SPEC_EXTR (sloc->etype) = 0;
521 /* we don't allow it to be allocated`
522 onto the external stack since : so we
523 temporarily turn it off ; we also
524 turn off memory model to prevent
525 the spil from going to the external storage
528 useXstack = options.useXstack;
529 model = options.model;
530 /* noOverlay = options.noOverlay; */
531 /* options.noOverlay = 1; */
532 options.model = options.useXstack = 0;
536 options.useXstack = useXstack;
537 options.model = model;
538 /* options.noOverlay = noOverlay; */
539 sloc->isref = 1; /* to prevent compiler warning */
541 /* if it is on the stack then update the stack */
542 if (IN_STACK (sloc->etype))
544 currFunc->stack += getSize (sloc->type);
545 _G.stackExtend += getSize (sloc->type);
548 _G.dataExtend += getSize (sloc->type);
550 /* add it to the _G.stackSpil set */
551 addSetHead (&_G.stackSpil, sloc);
552 sym->usl.spillLoc = sloc;
555 /* add it to the set of itempStack set
556 of the spill location */
557 addSetHead (&sloc->usl.itmpStack, sym);
561 /*-----------------------------------------------------------------*/
562 /* isSpiltOnStack - returns true if the spil location is on stack */
563 /*-----------------------------------------------------------------*/
565 isSpiltOnStack (symbol * sym)
575 /* if (sym->_G.stackSpil) */
578 if (!sym->usl.spillLoc)
581 etype = getSpec (sym->usl.spillLoc->type);
582 if (IN_STACK (etype))
588 /*-----------------------------------------------------------------*/
589 /* spillThis - spils a specific operand */
590 /*-----------------------------------------------------------------*/
592 spillThis (symbol * sym)
595 /* if this is rematerializable or has a spillLocation
596 we are okay, else we need to create a spillLocation
598 if (!(sym->remat || sym->usl.spillLoc))
599 createStackSpil (sym);
602 /* mark it has spilt & put it in the spilt set */
604 _G.spiltSet = bitVectSetBit (_G.spiltSet, sym->key);
606 bitVectUnSetBit (_G.regAssigned, sym->key);
608 for (i = 0; i < sym->nRegs; i++)
612 freeReg (sym->regs[i]);
616 /* if spilt on stack then free up r0 & r1
617 if they could have been assigned to some
619 if (!mcs51_ptrRegReq && isSpiltOnStack (sym))
622 spillLRWithPtrReg (sym);
625 if (sym->usl.spillLoc && !sym->remat)
626 sym->usl.spillLoc->allocreq = 1;
630 /*-----------------------------------------------------------------*/
631 /* selectSpil - select a iTemp to spil : rather a simple procedure */
632 /*-----------------------------------------------------------------*/
634 selectSpil (iCode * ic, eBBlock * ebp, symbol * forSym)
636 bitVect *lrcs = NULL;
640 /* get the spillable live ranges */
641 lrcs = computeSpillable (ic);
643 /* get all live ranges that are rematerizable */
644 if ((selectS = liveRangesWith (lrcs, rematable, ebp, ic)))
647 /* return the least used of these */
648 return leastUsedLR (selectS);
651 /* get live ranges with spillLocations in direct space */
652 if ((selectS = liveRangesWith (lrcs, directSpilLoc, ebp, ic)))
654 sym = leastUsedLR (selectS);
655 strcpy (sym->rname, (sym->usl.spillLoc->rname[0] ?
656 sym->usl.spillLoc->rname :
657 sym->usl.spillLoc->name));
659 /* mark it as allocation required */
660 sym->usl.spillLoc->allocreq = 1;
664 /* if the symbol is local to the block then */
665 if (forSym->liveTo < ebp->lSeq)
668 /* check if there are any live ranges allocated
669 to registers that are not used in this block */
670 if (!_G.blockSpil && (selectS = liveRangesWith (lrcs, notUsedInBlock, ebp, ic)))
672 sym = leastUsedLR (selectS);
673 /* if this is not rematerializable */
682 /* check if there are any live ranges that not
683 used in the remainder of the block */
684 if (!_G.blockSpil && (selectS = liveRangesWith (lrcs, notUsedInRemaining, ebp, ic)))
686 sym = leastUsedLR (selectS);
699 /* find live ranges with spillocation && not used as pointers */
700 if ((selectS = liveRangesWith (lrcs, hasSpilLocnoUptr, ebp, ic)))
703 sym = leastUsedLR (selectS);
704 /* mark this as allocation required */
705 sym->usl.spillLoc->allocreq = 1;
709 /* find live ranges with spillocation */
710 if ((selectS = liveRangesWith (lrcs, hasSpilLoc, ebp, ic)))
713 sym = leastUsedLR (selectS);
714 sym->usl.spillLoc->allocreq = 1;
718 /* couldn't find then we need to create a spil
719 location on the stack , for which one? the least
721 if ((selectS = liveRangesWith (lrcs, noSpilLoc, ebp, ic)))
724 /* return a created spil location */
725 sym = createStackSpil (leastUsedLR (selectS));
726 sym->usl.spillLoc->allocreq = 1;
730 /* this is an extreme situation we will spill
731 this one : happens very rarely but it does happen */
737 /*-----------------------------------------------------------------*/
738 /* spilSomething - spil some variable & mark registers as free */
739 /*-----------------------------------------------------------------*/
741 spilSomething (iCode * ic, eBBlock * ebp, symbol * forSym)
746 /* get something we can spil */
747 ssym = selectSpil (ic, ebp, forSym);
749 /* mark it as spilt */
751 _G.spiltSet = bitVectSetBit (_G.spiltSet, ssym->key);
753 /* mark it as not register assigned &
754 take it away from the set */
755 bitVectUnSetBit (_G.regAssigned, ssym->key);
757 /* mark the registers as free */
758 for (i = 0; i < ssym->nRegs; i++)
760 freeReg (ssym->regs[i]);
762 /* if spilt on stack then free up r0 & r1
763 if they could have been assigned to as gprs */
764 if (!mcs51_ptrRegReq && isSpiltOnStack (ssym))
767 spillLRWithPtrReg (ssym);
770 /* if this was a block level spil then insert push & pop
771 at the start & end of block respectively */
774 iCode *nic = newiCode (IPUSH, operandFromSymbol (ssym), NULL);
775 /* add push to the start of the block */
776 addiCodeToeBBlock (ebp, nic, (ebp->sch->op == LABEL ?
777 ebp->sch->next : ebp->sch));
778 nic = newiCode (IPOP, operandFromSymbol (ssym), NULL);
779 /* add pop to the end of the block */
780 addiCodeToeBBlock (ebp, nic, NULL);
783 /* if spilt because not used in the remainder of the
784 block then add a push before this instruction and
785 a pop at the end of the block */
786 if (ssym->remainSpil)
789 iCode *nic = newiCode (IPUSH, operandFromSymbol (ssym), NULL);
790 /* add push just before this instruction */
791 addiCodeToeBBlock (ebp, nic, ic);
793 nic = newiCode (IPOP, operandFromSymbol (ssym), NULL);
794 /* add pop to the end of the block */
795 addiCodeToeBBlock (ebp, nic, NULL);
804 /*-----------------------------------------------------------------*/
805 /* getRegPtr - will try for PTR if not a GPR type if not spil */
806 /*-----------------------------------------------------------------*/
808 getRegPtr (iCode * ic, eBBlock * ebp, symbol * sym)
813 /* try for a ptr type */
814 if ((reg = allocReg (REG_PTR)))
817 /* try for gpr type */
818 if ((reg = allocReg (REG_GPR)))
821 /* we have to spil */
822 if (!spilSomething (ic, ebp, sym))
825 /* this looks like an infinite loop but
826 in really selectSpil will abort */
830 /*-----------------------------------------------------------------*/
831 /* getRegGpr - will try for GPR if not spil */
832 /*-----------------------------------------------------------------*/
834 getRegGpr (iCode * ic, eBBlock * ebp, symbol * sym)
839 /* try for gpr type */
840 if ((reg = allocReg (REG_GPR)))
843 if (!mcs51_ptrRegReq)
844 if ((reg = allocReg (REG_PTR)))
847 /* we have to spil */
848 if (!spilSomething (ic, ebp, sym))
851 /* this looks like an infinite loop but
852 in really selectSpil will abort */
856 /*-----------------------------------------------------------------*/
857 /* symHasReg - symbol has a given register */
858 /*-----------------------------------------------------------------*/
860 symHasReg (symbol * sym, regs * reg)
864 for (i = 0; i < sym->nRegs; i++)
865 if (sym->regs[i] == reg)
871 /*-----------------------------------------------------------------*/
872 /* deassignLRs - check the live to and if they have registers & are */
873 /* not spilt then free up the registers */
874 /*-----------------------------------------------------------------*/
876 deassignLRs (iCode * ic, eBBlock * ebp)
882 for (sym = hTabFirstItem (liveRanges, &k); sym;
883 sym = hTabNextItem (liveRanges, &k))
887 /* if it does not end here */
888 if (sym->liveTo > ic->seq)
891 /* if it was spilt on stack then we can
892 mark the stack spil location as free */
897 sym->usl.spillLoc->isFree = 1;
903 if (!bitVectBitValue (_G.regAssigned, sym->key))
906 /* special case check if this is an IFX &
907 the privious one was a pop and the
908 previous one was not spilt then keep track
910 if (ic->op == IFX && ic->prev &&
911 ic->prev->op == IPOP &&
912 !ic->prev->parmPush &&
913 !OP_SYMBOL (IC_LEFT (ic->prev))->isspilt)
914 psym = OP_SYMBOL (IC_LEFT (ic->prev));
920 bitVectUnSetBit (_G.regAssigned, sym->key);
922 /* if the result of this one needs registers
923 and does not have it then assign it right
925 if (IC_RESULT (ic) &&
926 !(SKIP_IC2 (ic) || /* not a special icode */
927 ic->op == JUMPTABLE ||
933 (result = OP_SYMBOL (IC_RESULT (ic))) && /* has a result */
934 result->liveTo > ic->seq && /* and will live beyond this */
935 result->liveTo <= ebp->lSeq && /* does not go beyond this block */
936 result->regType == sym->regType && /* same register types */
937 result->nRegs && /* which needs registers */
938 !result->isspilt && /* and does not already have them */
940 !bitVectBitValue (_G.regAssigned, result->key) &&
941 /* the number of free regs + number of regs in this LR
942 can accomodate the what result Needs */
943 ((nfreeRegsType (result->regType) +
944 sym->nRegs) >= result->nRegs)
948 for (i = 0; i < result->nRegs; i++)
950 result->regs[i] = sym->regs[i];
952 result->regs[i] = getRegGpr (ic, ebp, result);
954 _G.regAssigned = bitVectSetBit (_G.regAssigned, result->key);
958 /* free the remaining */
959 for (; i < sym->nRegs; i++)
963 if (!symHasReg (psym, sym->regs[i]))
964 freeReg (sym->regs[i]);
967 freeReg (sym->regs[i]);
974 /*-----------------------------------------------------------------*/
975 /* reassignLR - reassign this to registers */
976 /*-----------------------------------------------------------------*/
978 reassignLR (operand * op)
980 symbol *sym = OP_SYMBOL (op);
983 /* not spilt any more */
984 sym->isspilt = sym->blockSpil = sym->remainSpil = 0;
985 bitVectUnSetBit (_G.spiltSet, sym->key);
987 _G.regAssigned = bitVectSetBit (_G.regAssigned, sym->key);
991 for (i = 0; i < sym->nRegs; i++)
992 sym->regs[i]->isFree = 0;
995 /*-----------------------------------------------------------------*/
996 /* willCauseSpill - determines if allocating will cause a spill */
997 /*-----------------------------------------------------------------*/
999 willCauseSpill (int nr, int rt)
1001 /* first check if there are any avlb registers
1002 of te type required */
1005 /* special case for pointer type
1006 if pointer type not avlb then
1007 check for type gpr */
1008 if (nFreeRegs (rt) >= nr)
1010 if (nFreeRegs (REG_GPR) >= nr)
1015 if (mcs51_ptrRegReq)
1017 if (nFreeRegs (rt) >= nr)
1022 if (nFreeRegs (REG_PTR) +
1023 nFreeRegs (REG_GPR) >= nr)
1028 /* it will cause a spil */
1032 /*-----------------------------------------------------------------*/
1033 /* positionRegs - the allocator can allocate same registers to res- */
1034 /* ult and operand, if this happens make sure they are in the same */
1035 /* position as the operand otherwise chaos results */
1036 /*-----------------------------------------------------------------*/
1038 positionRegs (symbol * result, symbol * opsym, int lineno)
1040 int count = min (result->nRegs, opsym->nRegs);
1041 int i, j = 0, shared = 0;
1043 /* if the result has been spilt then cannot share */
1048 /* first make sure that they actually share */
1049 for (i = 0; i < count; i++)
1051 for (j = 0; j < count; j++)
1053 if (result->regs[i] == opsym->regs[j] && i != j)
1063 regs *tmp = result->regs[i];
1064 result->regs[i] = result->regs[j];
1065 result->regs[j] = tmp;
1070 /*-----------------------------------------------------------------*/
1071 /* serialRegAssign - serially allocate registers to the variables */
1072 /*-----------------------------------------------------------------*/
1074 serialRegAssign (eBBlock ** ebbs, int count)
1078 /* for all blocks */
1079 for (i = 0; i < count; i++) {
1083 if (ebbs[i]->noPath &&
1084 (ebbs[i]->entryLabel != entryLabel &&
1085 ebbs[i]->entryLabel != returnLabel))
1088 /* of all instructions do */
1089 for (ic = ebbs[i]->sch; ic; ic = ic->next) {
1091 /* if this is an ipop that means some live
1092 range will have to be assigned again */
1094 reassignLR (IC_LEFT (ic));
1096 /* if result is present && is a true symbol */
1097 if (IC_RESULT (ic) && ic->op != IFX &&
1098 IS_TRUE_SYMOP (IC_RESULT (ic)))
1099 OP_SYMBOL (IC_RESULT (ic))->allocreq = 1;
1101 /* take away registers from live
1102 ranges that end at this instruction */
1103 deassignLRs (ic, ebbs[i]);
1105 /* some don't need registers */
1106 if (SKIP_IC2 (ic) ||
1107 ic->op == JUMPTABLE ||
1111 (IC_RESULT (ic) && POINTER_SET (ic)))
1114 /* now we need to allocate registers
1115 only for the result */
1116 if (IC_RESULT (ic)) {
1117 symbol *sym = OP_SYMBOL (IC_RESULT (ic));
1123 /* if it does not need or is spilt
1124 or is already assigned to registers
1125 or will not live beyond this instructions */
1128 bitVectBitValue (_G.regAssigned, sym->key) ||
1129 sym->liveTo <= ic->seq)
1132 /* if some liverange has been spilt at the block level
1133 and this one live beyond this block then spil this
1135 if (_G.blockSpil && sym->liveTo > ebbs[i]->lSeq) {
1139 /* if trying to allocate this will cause
1140 a spill and there is nothing to spill
1141 or this one is rematerializable then
1143 willCS = willCauseSpill (sym->nRegs, sym->regType);
1144 spillable = computeSpillable (ic);
1145 if (sym->remat || (willCS && bitVectIsZero (spillable))) {
1150 /* if it has a spillocation & is used less than
1151 all other live ranges then spill this */
1153 if (sym->usl.spillLoc) {
1154 symbol *leastUsed = leastUsedLR (liveRangesWith (spillable,
1155 allLRs, ebbs[i], ic));
1156 if (leastUsed && leastUsed->used > sym->used) {
1161 /* if none of the liveRanges have a spillLocation then better
1162 to spill this one than anything else already assigned to registers */
1163 if (liveRangesWith(spillable,noSpilLoc,ebbs[i],ic)) {
1169 /* if we need ptr regs for the right side
1171 if (POINTER_GET (ic) && IS_SYMOP (IC_LEFT (ic))
1172 && getSize (OP_SYMBOL (IC_LEFT (ic))->type) <= (unsigned int) PTRSIZE) {
1176 /* else we assign registers to it */
1177 _G.regAssigned = bitVectSetBit (_G.regAssigned, sym->key);
1179 for (j = 0; j < sym->nRegs; j++) {
1180 if (sym->regType == REG_PTR)
1181 sym->regs[j] = getRegPtr (ic, ebbs[i], sym);
1183 sym->regs[j] = getRegGpr (ic, ebbs[i], sym);
1185 /* if the allocation falied which means
1186 this was spilt then break */
1191 /* if it shares registers with operands make sure
1192 that they are in the same position */
1193 if (IC_LEFT (ic) && IS_SYMOP (IC_LEFT (ic)) &&
1194 OP_SYMBOL (IC_LEFT (ic))->nRegs && ic->op != '=') {
1195 positionRegs (OP_SYMBOL (IC_RESULT (ic)),
1196 OP_SYMBOL (IC_LEFT (ic)), ic->lineno);
1198 /* do the same for the right operand */
1199 if (IC_RIGHT (ic) && IS_SYMOP (IC_RIGHT (ic)) &&
1200 OP_SYMBOL (IC_RIGHT (ic))->nRegs) {
1201 positionRegs (OP_SYMBOL (IC_RESULT (ic)),
1202 OP_SYMBOL (IC_RIGHT (ic)), ic->lineno);
1215 /*-----------------------------------------------------------------*/
1216 /* rUmaskForOp :- returns register mask for an operand */
1217 /*-----------------------------------------------------------------*/
1219 rUmaskForOp (operand * op)
1225 /* only temporaries are assigned registers */
1229 sym = OP_SYMBOL (op);
1231 /* if spilt or no registers assigned to it
1233 if (sym->isspilt || !sym->nRegs)
1236 rumask = newBitVect (mcs51_nRegs);
1238 for (j = 0; j < sym->nRegs; j++)
1240 rumask = bitVectSetBit (rumask,
1241 sym->regs[j]->rIdx);
1247 /*-----------------------------------------------------------------*/
1248 /* regsUsedIniCode :- returns bit vector of registers used in iCode */
1249 /*-----------------------------------------------------------------*/
1251 regsUsedIniCode (iCode * ic)
1253 bitVect *rmask = newBitVect (mcs51_nRegs);
1255 /* do the special cases first */
1258 rmask = bitVectUnion (rmask,
1259 rUmaskForOp (IC_COND (ic)));
1263 /* for the jumptable */
1264 if (ic->op == JUMPTABLE)
1266 rmask = bitVectUnion (rmask,
1267 rUmaskForOp (IC_JTCOND (ic)));
1272 /* of all other cases */
1274 rmask = bitVectUnion (rmask,
1275 rUmaskForOp (IC_LEFT (ic)));
1279 rmask = bitVectUnion (rmask,
1280 rUmaskForOp (IC_RIGHT (ic)));
1283 rmask = bitVectUnion (rmask,
1284 rUmaskForOp (IC_RESULT (ic)));
1290 /*-----------------------------------------------------------------*/
1291 /* createRegMask - for each instruction will determine the regsUsed */
1292 /*-----------------------------------------------------------------*/
1294 createRegMask (eBBlock ** ebbs, int count)
1298 /* for all blocks */
1299 for (i = 0; i < count; i++)
1303 if (ebbs[i]->noPath &&
1304 (ebbs[i]->entryLabel != entryLabel &&
1305 ebbs[i]->entryLabel != returnLabel))
1308 /* for all instructions */
1309 for (ic = ebbs[i]->sch; ic; ic = ic->next)
1314 if (SKIP_IC2 (ic) || !ic->rlive)
1317 /* first mark the registers used in this
1319 ic->rUsed = regsUsedIniCode (ic);
1320 _G.funcrUsed = bitVectUnion (_G.funcrUsed, ic->rUsed);
1322 /* now create the register mask for those
1323 registers that are in use : this is a
1324 super set of ic->rUsed */
1325 ic->rMask = newBitVect (mcs51_nRegs + 1);
1327 /* for all live Ranges alive at this point */
1328 for (j = 1; j < ic->rlive->size; j++)
1333 /* if not alive then continue */
1334 if (!bitVectBitValue (ic->rlive, j))
1337 /* find the live range we are interested in */
1338 if (!(sym = hTabItemWithKey (liveRanges, j)))
1340 werror (E_INTERNAL_ERROR, __FILE__, __LINE__,
1341 "createRegMask cannot find live range");
1345 /* if no register assigned to it */
1346 if (!sym->nRegs || sym->isspilt)
1349 /* for all the registers allocated to it */
1350 for (k = 0; k < sym->nRegs; k++)
1353 bitVectSetBit (ic->rMask, sym->regs[k]->rIdx);
1359 /*-----------------------------------------------------------------*/
1360 /* rematStr - returns the rematerialized string for a remat var */
1361 /*-----------------------------------------------------------------*/
1363 rematStr (symbol * sym)
1366 iCode *ic = sym->rematiCode;
1371 /* if plus or minus print the right hand side */
1372 if (ic->op == '+' || ic->op == '-')
1374 sprintf (s, "0x%04x %c ", (int) operandLitValue (IC_RIGHT (ic)),
1377 ic = OP_SYMBOL (IC_LEFT (ic))->rematiCode;
1381 /* we reached the end */
1382 sprintf (s, "%s", OP_SYMBOL (IC_LEFT (ic))->rname);
1389 /*-----------------------------------------------------------------*/
1390 /* regTypeNum - computes the type & number of registers required */
1391 /*-----------------------------------------------------------------*/
1399 /* for each live range do */
1400 for (sym = hTabFirstItem (liveRanges, &k); sym;
1401 sym = hTabNextItem (liveRanges, &k))
1404 /* if used zero times then no registers needed */
1405 if ((sym->liveTo - sym->liveFrom) == 0)
1409 /* if the live range is a temporary */
1413 /* if the type is marked as a conditional */
1414 if (sym->regType == REG_CND)
1417 /* if used in return only then we don't
1419 if (sym->ruonly || sym->accuse)
1421 if (IS_AGGREGATE (sym->type) || sym->isptr)
1422 sym->type = aggrToPtr (sym->type, FALSE);
1426 /* if the symbol has only one definition &
1427 that definition is a get_pointer and the
1428 pointer we are getting is rematerializable and
1431 if (bitVectnBitsOn (sym->defs) == 1 &&
1432 (ic = hTabItemWithKey (iCodehTab,
1433 bitVectFirstBit (sym->defs))) &&
1436 !IS_BITVAR (sym->etype))
1440 /* if remat in data space */
1441 if (OP_SYMBOL (IC_LEFT (ic))->remat &&
1442 DCL_TYPE (aggrToPtr (sym->type, FALSE)) == POINTER)
1445 /* create a psuedo symbol & force a spil */
1446 symbol *psym = newSymbol (rematStr (OP_SYMBOL (IC_LEFT (ic))), 1);
1447 psym->type = sym->type;
1448 psym->etype = sym->etype;
1449 strcpy (psym->rname, psym->name);
1451 sym->usl.spillLoc = psym;
1455 /* if in data space or idata space then try to
1456 allocate pointer register */
1460 /* if not then we require registers */
1461 sym->nRegs = ((IS_AGGREGATE (sym->type) || sym->isptr) ?
1462 getSize (sym->type = aggrToPtr (sym->type, FALSE)) :
1463 getSize (sym->type));
1467 fprintf (stderr, "allocated more than 4 or 0 registers for type ");
1468 printTypeChain (sym->type, stderr);
1469 fprintf (stderr, "\n");
1472 /* determine the type of register required */
1473 if (sym->nRegs == 1 &&
1474 IS_PTR (sym->type) &&
1476 sym->regType = REG_PTR;
1478 sym->regType = REG_GPR;
1482 /* for the first run we don't provide */
1483 /* registers for true symbols we will */
1484 /* see how things go */
1490 /*-----------------------------------------------------------------*/
1491 /* freeAllRegs - mark all registers as free */
1492 /*-----------------------------------------------------------------*/
1498 for (i = 0; i < mcs51_nRegs; i++)
1499 regs8051[i].isFree = 1;
1502 /*-----------------------------------------------------------------*/
1503 /* deallocStackSpil - this will set the stack pointer back */
1504 /*-----------------------------------------------------------------*/
1506 DEFSETFUNC (deallocStackSpil)
1514 /*-----------------------------------------------------------------*/
1515 /* farSpacePackable - returns the packable icode for far variables */
1516 /*-----------------------------------------------------------------*/
1518 farSpacePackable (iCode * ic)
1522 /* go thru till we find a definition for the
1523 symbol on the right */
1524 for (dic = ic->prev; dic; dic = dic->prev)
1526 /* if the definition is a call then no */
1527 if ((dic->op == CALL || dic->op == PCALL) &&
1528 IC_RESULT (dic)->key == IC_RIGHT (ic)->key)
1533 /* if shift by unknown amount then not */
1534 if ((dic->op == LEFT_OP || dic->op == RIGHT_OP) &&
1535 IC_RESULT (dic)->key == IC_RIGHT (ic)->key)
1538 /* if pointer get and size > 1 */
1539 if (POINTER_GET (dic) &&
1540 getSize (aggrToPtr (operandType (IC_LEFT (dic)), FALSE)) > 1)
1543 if (POINTER_SET (dic) &&
1544 getSize (aggrToPtr (operandType (IC_RESULT (dic)), FALSE)) > 1)
1547 /* if any three is a true symbol in far space */
1548 if (IC_RESULT (dic) &&
1549 IS_TRUE_SYMOP (IC_RESULT (dic)) &&
1550 isOperandInFarSpace (IC_RESULT (dic)))
1553 if (IC_RIGHT (dic) &&
1554 IS_TRUE_SYMOP (IC_RIGHT (dic)) &&
1555 isOperandInFarSpace (IC_RIGHT (dic)) &&
1556 !isOperandEqual (IC_RIGHT (dic), IC_RESULT (ic)))
1559 if (IC_LEFT (dic) &&
1560 IS_TRUE_SYMOP (IC_LEFT (dic)) &&
1561 isOperandInFarSpace (IC_LEFT (dic)) &&
1562 !isOperandEqual (IC_LEFT (dic), IC_RESULT (ic)))
1565 if (isOperandEqual (IC_RIGHT (ic), IC_RESULT (dic)))
1567 if ((dic->op == LEFT_OP ||
1568 dic->op == RIGHT_OP ||
1570 IS_OP_LITERAL (IC_RIGHT (dic)))
1580 /*-----------------------------------------------------------------*/
1581 /* packRegsForAssign - register reduction for assignment */
1582 /*-----------------------------------------------------------------*/
1584 packRegsForAssign (iCode * ic, eBBlock * ebp)
1587 //sym_link *etype = operandType (IC_RIGHT (ic));
1589 if (!IS_ITEMP (IC_RIGHT (ic)) ||
1590 OP_SYMBOL (IC_RIGHT (ic))->isind ||
1591 OP_LIVETO (IC_RIGHT (ic)) > ic->seq
1592 /* why? || IS_BITFIELD (etype) */ )
1597 /* if the true symbol is defined in far space or on stack
1598 then we should not since this will increase register pressure */
1599 if (isOperandInFarSpace(IC_RESULT(ic)) && !farSpacePackable(ic)) {
1603 /* find the definition of iTempNN scanning backwards if we find a
1604 a use of the true symbol in before we find the definition then
1606 for (dic = ic->prev; dic; dic = dic->prev)
1608 /* if there is a function call then don't pack it */
1609 if ((dic->op == CALL || dic->op == PCALL))
1618 if (IS_TRUE_SYMOP (IC_RESULT (dic)) &&
1619 IS_OP_VOLATILE (IC_RESULT (dic)))
1625 if (IS_SYMOP (IC_RESULT (dic)) &&
1626 IC_RESULT (dic)->key == IC_RIGHT (ic)->key)
1628 if (POINTER_SET (dic))
1634 if (IS_SYMOP (IC_RIGHT (dic)) &&
1635 (IC_RIGHT (dic)->key == IC_RESULT (ic)->key ||
1636 IC_RIGHT (dic)->key == IC_RIGHT (ic)->key))
1642 if (IS_SYMOP (IC_LEFT (dic)) &&
1643 (IC_LEFT (dic)->key == IC_RESULT (ic)->key ||
1644 IC_LEFT (dic)->key == IC_RIGHT (ic)->key))
1650 if (POINTER_SET (dic) &&
1651 IC_RESULT (dic)->key == IC_RESULT (ic)->key)
1659 return 0; /* did not find */
1661 /* if assignment then check that right is not a bit */
1662 if (ASSIGNMENT (dic) && !POINTER_SET (dic))
1664 sym_link *etype = operandType (IC_RIGHT (dic));
1665 if (IS_BITFIELD (etype))
1668 /* if the result is on stack or iaccess then it must be
1669 the same atleast one of the operands */
1670 if (OP_SYMBOL (IC_RESULT (ic))->onStack ||
1671 OP_SYMBOL (IC_RESULT (ic))->iaccess)
1674 /* the operation has only one symbol
1675 operator then we can pack */
1676 if ((IC_LEFT (dic) && !IS_SYMOP (IC_LEFT (dic))) ||
1677 (IC_RIGHT (dic) && !IS_SYMOP (IC_RIGHT (dic))))
1680 if (!((IC_LEFT (dic) &&
1681 IC_RESULT (ic)->key == IC_LEFT (dic)->key) ||
1683 IC_RESULT (ic)->key == IC_RIGHT (dic)->key)))
1687 /* found the definition */
1688 /* replace the result with the result of */
1689 /* this assignment and remove this assignment */
1690 IC_RESULT (dic) = IC_RESULT (ic);
1692 if (IS_ITEMP (IC_RESULT (dic)) && OP_SYMBOL (IC_RESULT (dic))->liveFrom > dic->seq)
1694 OP_SYMBOL (IC_RESULT (dic))->liveFrom = dic->seq;
1696 /* delete from liverange table also
1697 delete from all the points inbetween and the new
1699 for (sic = dic; sic != ic; sic = sic->next)
1701 bitVectUnSetBit (sic->rlive, IC_RESULT (ic)->key);
1702 if (IS_ITEMP (IC_RESULT (dic)))
1703 bitVectSetBit (sic->rlive, IC_RESULT (dic)->key);
1706 remiCodeFromeBBlock (ebp, ic);
1707 hTabDeleteItem (&iCodehTab, ic->key, ic, DELETE_ITEM, NULL);
1708 OP_DEFS (IC_RESULT (dic)) = bitVectSetBit (OP_DEFS (IC_RESULT (dic)), dic->key);
1713 /*-----------------------------------------------------------------*/
1714 /* findAssignToSym : scanning backwards looks for first assig found */
1715 /*-----------------------------------------------------------------*/
1717 findAssignToSym (operand * op, iCode * ic)
1721 for (dic = ic->prev; dic; dic = dic->prev)
1724 /* if definition by assignment */
1725 if (dic->op == '=' &&
1726 !POINTER_SET (dic) &&
1727 IC_RESULT (dic)->key == op->key
1728 /* && IS_TRUE_SYMOP(IC_RIGHT(dic)) */
1732 /* we are interested only if defined in far space */
1733 /* or in stack space in case of + & - */
1735 /* if assigned to a non-symbol then return
1737 if (!IS_SYMOP (IC_RIGHT (dic)))
1740 /* if the symbol is in far space then
1742 if (isOperandInFarSpace (IC_RIGHT (dic)))
1745 /* for + & - operations make sure that
1746 if it is on the stack it is the same
1747 as one of the three operands */
1748 if ((ic->op == '+' || ic->op == '-') &&
1749 OP_SYMBOL (IC_RIGHT (dic))->onStack)
1752 if (IC_RESULT (ic)->key != IC_RIGHT (dic)->key &&
1753 IC_LEFT (ic)->key != IC_RIGHT (dic)->key &&
1754 IC_RIGHT (ic)->key != IC_RIGHT (dic)->key)
1762 /* if we find an usage then we cannot delete it */
1763 if (IC_LEFT (dic) && IC_LEFT (dic)->key == op->key)
1766 if (IC_RIGHT (dic) && IC_RIGHT (dic)->key == op->key)
1769 if (POINTER_SET (dic) && IC_RESULT (dic)->key == op->key)
1773 /* now make sure that the right side of dic
1774 is not defined between ic & dic */
1777 iCode *sic = dic->next;
1779 for (; sic != ic; sic = sic->next)
1780 if (IC_RESULT (sic) &&
1781 IC_RESULT (sic)->key == IC_RIGHT (dic)->key)
1790 /*-----------------------------------------------------------------*/
1791 /* packRegsForSupport :- reduce some registers for support calls */
1792 /*-----------------------------------------------------------------*/
1794 packRegsForSupport (iCode * ic, eBBlock * ebp)
1799 /* for the left & right operand :- look to see if the
1800 left was assigned a true symbol in far space in that
1801 case replace them */
1803 if (IS_ITEMP (IC_LEFT (ic)) &&
1804 OP_SYMBOL (IC_LEFT (ic))->liveTo <= ic->seq)
1806 dic = findAssignToSym (IC_LEFT (ic), ic);
1811 /* found it we need to remove it from the
1813 for (sic = dic; sic != ic; sic = sic->next)
1814 bitVectUnSetBit (sic->rlive, IC_LEFT (ic)->key);
1816 OP_SYMBOL(IC_LEFT (ic))=OP_SYMBOL(IC_RIGHT (dic));
1817 IC_LEFT (ic)->key = OP_SYMBOL(IC_RIGHT (dic))->key;
1818 remiCodeFromeBBlock (ebp, dic);
1819 hTabDeleteItem (&iCodehTab, dic->key, dic, DELETE_ITEM, NULL);
1823 /* do the same for the right operand */
1826 IS_ITEMP (IC_RIGHT (ic)) &&
1827 OP_SYMBOL (IC_RIGHT (ic))->liveTo <= ic->seq)
1829 iCode *dic = findAssignToSym (IC_RIGHT (ic), ic);
1835 /* if this is a subtraction & the result
1836 is a true symbol in far space then don't pack */
1837 if (ic->op == '-' && IS_TRUE_SYMOP (IC_RESULT (dic)))
1839 sym_link *etype = getSpec (operandType (IC_RESULT (dic)));
1840 if (IN_FARSPACE (SPEC_OCLS (etype)))
1843 /* found it we need to remove it from the
1845 for (sic = dic; sic != ic; sic = sic->next)
1846 bitVectUnSetBit (sic->rlive, IC_RIGHT (ic)->key);
1848 IC_RIGHT (ic)->operand.symOperand =
1849 IC_RIGHT (dic)->operand.symOperand;
1850 IC_RIGHT (ic)->key = IC_RIGHT (dic)->operand.symOperand->key;
1852 remiCodeFromeBBlock (ebp, dic);
1853 hTabDeleteItem (&iCodehTab, dic->key, dic, DELETE_ITEM, NULL);
1860 #define IS_OP_RUONLY(x) (x && IS_SYMOP(x) && OP_SYMBOL(x)->ruonly)
1863 /*-----------------------------------------------------------------*/
1864 /* packRegsForOneuse : - will reduce some registers for single Use */
1865 /*-----------------------------------------------------------------*/
1867 packRegsForOneuse (iCode * ic, operand * op, eBBlock * ebp)
1872 /* if returning a literal then do nothing */
1876 /* only upto 2 bytes since we cannot predict
1877 the usage of b, & acc */
1878 if (getSize (operandType (op)) > (fReturnSizeMCS51 - 2))
1881 if (ic->op != RETURN &&
1883 !POINTER_SET (ic) &&
1887 /* this routine will mark the a symbol as used in one
1888 instruction use only && if the defintion is local
1889 (ie. within the basic block) && has only one definition &&
1890 that definiion is either a return value from a
1891 function or does not contain any variables in
1893 uses = bitVectCopy (OP_USES (op));
1894 bitVectUnSetBit (uses, ic->key); /* take away this iCode */
1895 if (!bitVectIsZero (uses)) /* has other uses */
1898 /* if it has only one defintion */
1899 if (bitVectnBitsOn (OP_DEFS (op)) > 1)
1900 return NULL; /* has more than one definition */
1902 /* get that definition */
1904 hTabItemWithKey (iCodehTab,
1905 bitVectFirstBit (OP_DEFS (op)))))
1908 /* if that only usage is a cast */
1909 if (dic->op == CAST) {
1910 /* to a bigger type */
1911 if (getSize(OP_SYM_TYPE(IC_RESULT(dic))) >
1912 getSize(OP_SYM_TYPE(IC_RIGHT(dic)))) {
1913 /* than we can not, since we cannot predict the usage of b & acc */
1918 /* found the definition now check if it is local */
1919 if (dic->seq < ebp->fSeq ||
1920 dic->seq > ebp->lSeq)
1921 return NULL; /* non-local */
1923 /* now check if it is the return from
1925 if (dic->op == CALL || dic->op == PCALL)
1927 if (ic->op != SEND && ic->op != RETURN)
1929 OP_SYMBOL (op)->ruonly = 1;
1936 /* otherwise check that the definition does
1937 not contain any symbols in far space */
1938 if (isOperandInFarSpace (IC_LEFT (dic)) ||
1939 isOperandInFarSpace (IC_RIGHT (dic)) ||
1940 IS_OP_RUONLY (IC_LEFT (ic)) ||
1941 IS_OP_RUONLY (IC_RIGHT (ic)))
1946 /* if pointer set then make sure the pointer
1948 if (POINTER_SET (dic) &&
1949 !IS_DATA_PTR (aggrToPtr (operandType (IC_RESULT (dic)), FALSE)))
1952 if (POINTER_GET (dic) &&
1953 !IS_DATA_PTR (aggrToPtr (operandType (IC_LEFT (dic)), FALSE)))
1958 /* also make sure the intervenening instructions
1959 don't have any thing in far space */
1960 for (dic = dic->next; dic && dic != ic && sic != ic; dic = dic->next)
1963 /* if there is an intervening function call then no */
1964 if (dic->op == CALL || dic->op == PCALL)
1966 /* if pointer set then make sure the pointer
1968 if (POINTER_SET (dic) &&
1969 !IS_DATA_PTR (aggrToPtr (operandType (IC_RESULT (dic)), FALSE)))
1972 if (POINTER_GET (dic) &&
1973 !IS_DATA_PTR (aggrToPtr (operandType (IC_LEFT (dic)), FALSE)))
1976 /* if address of & the result is remat the okay */
1977 if (dic->op == ADDRESS_OF &&
1978 OP_SYMBOL (IC_RESULT (dic))->remat)
1981 /* if operand has size of three or more & this
1982 operation is a '*','/' or '%' then 'b' may
1984 if ((dic->op == '%' || dic->op == '/' || dic->op == '*') &&
1985 getSize (operandType (op)) >= 3)
1988 /* if left or right or result is in far space */
1989 if (isOperandInFarSpace (IC_LEFT (dic)) ||
1990 isOperandInFarSpace (IC_RIGHT (dic)) ||
1991 isOperandInFarSpace (IC_RESULT (dic)) ||
1992 IS_OP_RUONLY (IC_LEFT (dic)) ||
1993 IS_OP_RUONLY (IC_RIGHT (dic)) ||
1994 IS_OP_RUONLY (IC_RESULT (dic)))
1998 /* if left or right or result is on stack */
1999 if (isOperandOnStack(IC_LEFT(dic)) ||
2000 isOperandOnStack(IC_RIGHT(dic)) ||
2001 isOperandOnStack(IC_RESULT(dic))) {
2006 OP_SYMBOL (op)->ruonly = 1;
2011 /*-----------------------------------------------------------------*/
2012 /* isBitwiseOptimizable - requirements of JEAN LOUIS VERN */
2013 /*-----------------------------------------------------------------*/
2015 isBitwiseOptimizable (iCode * ic)
2017 sym_link *ltype = getSpec (operandType (IC_LEFT (ic)));
2018 sym_link *rtype = getSpec (operandType (IC_RIGHT (ic)));
2020 /* bitwise operations are considered optimizable
2021 under the following conditions (Jean-Louis VERN)
2033 if (IS_LITERAL(rtype) ||
2034 (IS_BITVAR (ltype) && IN_BITSPACE (SPEC_OCLS (ltype))))
2040 /*-----------------------------------------------------------------*/
2041 /* packRegsForAccUse - pack registers for acc use */
2042 /*-----------------------------------------------------------------*/
2044 packRegsForAccUse (iCode * ic)
2048 /* if + or - then it has to be one byte result */
2049 if ((ic->op == '+' || ic->op == '-')
2050 && getSize (operandType (IC_RESULT (ic))) > 1)
2053 /* if shift operation make sure right side is not a literal */
2054 if (ic->op == RIGHT_OP &&
2055 (isOperandLiteral (IC_RIGHT (ic)) ||
2056 getSize (operandType (IC_RESULT (ic))) > 1))
2059 if (ic->op == LEFT_OP &&
2060 (isOperandLiteral (IC_RIGHT (ic)) ||
2061 getSize (operandType (IC_RESULT (ic))) > 1))
2064 if (IS_BITWISE_OP (ic) &&
2065 getSize (operandType (IC_RESULT (ic))) > 1)
2069 /* has only one definition */
2070 if (bitVectnBitsOn (OP_DEFS (IC_RESULT (ic))) > 1)
2073 /* has only one use */
2074 if (bitVectnBitsOn (OP_USES (IC_RESULT (ic))) > 1)
2077 /* and the usage immediately follows this iCode */
2078 if (!(uic = hTabItemWithKey (iCodehTab,
2079 bitVectFirstBit (OP_USES (IC_RESULT (ic))))))
2082 if (ic->next != uic)
2085 /* if it is a conditional branch then we definitely can */
2089 if (uic->op == JUMPTABLE)
2092 /* if the usage is not is an assignment
2093 or an arithmetic / bitwise / shift operation then not */
2094 if (POINTER_SET (uic) &&
2095 getSize (aggrToPtr (operandType (IC_RESULT (uic)), FALSE)) > 1)
2098 if (uic->op != '=' &&
2099 !IS_ARITHMETIC_OP (uic) &&
2100 !IS_BITWISE_OP (uic) &&
2101 uic->op != LEFT_OP &&
2102 uic->op != RIGHT_OP)
2105 /* if used in ^ operation then make sure right is not a
2107 if (uic->op == '^' && isOperandLiteral (IC_RIGHT (uic)))
2110 /* if shift operation make sure right side is not a literal */
2111 if (uic->op == RIGHT_OP &&
2112 (isOperandLiteral (IC_RIGHT (uic)) ||
2113 getSize (operandType (IC_RESULT (uic))) > 1))
2116 if (uic->op == LEFT_OP &&
2117 (isOperandLiteral (IC_RIGHT (uic)) ||
2118 getSize (operandType (IC_RESULT (uic))) > 1))
2121 /* make sure that the result of this icode is not on the
2122 stack, since acc is used to compute stack offset */
2123 if (IS_TRUE_SYMOP (IC_RESULT (uic)) &&
2124 OP_SYMBOL (IC_RESULT (uic))->onStack)
2127 /* if either one of them in far space then we cannot */
2128 if ((IS_TRUE_SYMOP (IC_LEFT (uic)) &&
2129 isOperandInFarSpace (IC_LEFT (uic))) ||
2130 (IS_TRUE_SYMOP (IC_RIGHT (uic)) &&
2131 isOperandInFarSpace (IC_RIGHT (uic))))
2134 /* if the usage has only one operand then we can */
2135 if (IC_LEFT (uic) == NULL ||
2136 IC_RIGHT (uic) == NULL)
2139 /* make sure this is on the left side if not
2140 a '+' since '+' is commutative */
2141 if (ic->op != '+' &&
2142 IC_LEFT (uic)->key != IC_RESULT (ic)->key)
2146 // this is too dangerous and need further restrictions
2149 /* if one of them is a literal then we can */
2150 if ((IC_LEFT (uic) && IS_OP_LITERAL (IC_LEFT (uic))) ||
2151 (IC_RIGHT (uic) && IS_OP_LITERAL (IC_RIGHT (uic))))
2153 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 /* make sure they have the same type */
2213 sym_link *itype=operandType(IC_LEFT(ic));
2214 sym_link *ditype=operandType(IC_RIGHT(dic));
2216 if (SPEC_USIGN(itype)!=SPEC_USIGN(ditype) ||
2217 SPEC_LONG(itype)!=SPEC_LONG(ditype))
2220 /* extend the live range of replaced operand if needed */
2221 if (OP_SYMBOL(IC_RIGHT(dic))->liveTo < ic->seq) {
2222 OP_SYMBOL(IC_RIGHT(dic))->liveTo = ic->seq;
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 an 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);
2339 /* if the condition of an if instruction
2340 is defined in the previous instruction and
2341 this is the only usage 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 bitVectnBitsOn (OP_USES(IC_RESULT(ic)))==1 &&
2347 isOperandEqual (IC_RESULT (ic), IC_COND (ic->next)) &&
2348 OP_SYMBOL (IC_RESULT (ic))->liveTo <= ic->next->seq)
2350 OP_SYMBOL (IC_RESULT (ic))->regType = REG_CND;
2354 /* reduce for support function calls */
2355 if (ic->supportRtn || ic->op == '+' || ic->op == '-')
2356 packRegsForSupport (ic, ebp);
2358 /* some cases the redundant moves can
2359 can be eliminated for return statements */
2360 if ((ic->op == RETURN || ic->op == SEND) &&
2361 !isOperandInFarSpace (IC_LEFT (ic)) &&
2362 options.model == MODEL_SMALL) {
2363 if (0 && options.stackAuto) {
2364 /* we should check here if acc will be clobbered for stack
2365 offset calculations */
2367 packRegsForOneuse (ic, IC_LEFT (ic), ebp);
2371 /* if pointer set & left has a size more than
2372 one and right is not in far space */
2373 if (POINTER_SET (ic) &&
2374 !isOperandInFarSpace (IC_RIGHT (ic)) &&
2375 !OP_SYMBOL (IC_RESULT (ic))->remat &&
2376 !IS_OP_RUONLY (IC_RIGHT (ic)) &&
2377 getSize (aggrToPtr (operandType (IC_RESULT (ic)), FALSE)) > 1)
2379 packRegsForOneuse (ic, IC_RESULT (ic), ebp);
2381 /* if pointer get */
2382 if (POINTER_GET (ic) &&
2383 !isOperandInFarSpace (IC_RESULT (ic)) &&
2384 !OP_SYMBOL (IC_LEFT (ic))->remat &&
2385 !IS_OP_RUONLY (IC_RESULT (ic)) &&
2386 getSize (aggrToPtr (operandType (IC_LEFT (ic)), FALSE)) > 1)
2388 packRegsForOneuse (ic, IC_LEFT (ic), ebp);
2391 /* if this is cast for intergral promotion then
2392 check if only use of the definition of the
2393 operand being casted/ if yes then replace
2394 the result of that arithmetic operation with
2395 this result and get rid of the cast */
2398 sym_link *fromType = operandType (IC_RIGHT (ic));
2399 sym_link *toType = operandType (IC_LEFT (ic));
2401 if (IS_INTEGRAL (fromType) && IS_INTEGRAL (toType) &&
2402 getSize (fromType) != getSize (toType) &&
2403 SPEC_USIGN (fromType) == SPEC_USIGN (toType))
2406 iCode *dic = packRegsForOneuse (ic, IC_RIGHT (ic), ebp);
2409 if (IS_ARITHMETIC_OP (dic))
2411 IC_RESULT (dic) = IC_RESULT (ic);
2412 remiCodeFromeBBlock (ebp, ic);
2413 hTabDeleteItem (&iCodehTab, ic->key, ic, DELETE_ITEM, NULL);
2414 OP_DEFS (IC_RESULT (dic)) = bitVectSetBit (OP_DEFS (IC_RESULT (dic)), dic->key);
2418 OP_SYMBOL (IC_RIGHT (ic))->ruonly = 0;
2424 /* if the type from and type to are the same
2425 then if this is the only use then packit */
2426 if (compareType (operandType (IC_RIGHT (ic)),
2427 operandType (IC_LEFT (ic))) == 1)
2429 iCode *dic = packRegsForOneuse (ic, IC_RIGHT (ic), ebp);
2432 IC_RESULT (dic) = IC_RESULT (ic);
2433 remiCodeFromeBBlock (ebp, ic);
2434 hTabDeleteItem (&iCodehTab, ic->key, ic, DELETE_ITEM, NULL);
2435 OP_DEFS (IC_RESULT (dic)) = bitVectSetBit (OP_DEFS (IC_RESULT (dic)), dic->key);
2443 iTempNN := (some variable in farspace) V1
2448 if (ic->op == IPUSH)
2450 packForPush (ic, ebp);
2454 /* pack registers for accumulator use, when the
2455 result of an arithmetic or bit wise operation
2456 has only one use, that use is immediately following
2457 the defintion and the using iCode has only one
2458 operand or has two operands but one is literal &
2459 the result of that operation is not on stack then
2460 we can leave the result of this operation in acc:b
2462 if ((IS_ARITHMETIC_OP (ic)
2463 || IS_CONDITIONAL(ic)
2464 || IS_BITWISE_OP (ic)
2465 || ic->op == LEFT_OP || ic->op == RIGHT_OP
2466 || (ic->op == ADDRESS_OF && isOperandOnStack (IC_LEFT (ic)))
2468 IS_ITEMP (IC_RESULT (ic)) &&
2469 getSize (operandType (IC_RESULT (ic))) <= 2)
2471 packRegsForAccUse (ic);
2475 /*-----------------------------------------------------------------*/
2476 /* assignRegisters - assigns registers to each live range as need */
2477 /*-----------------------------------------------------------------*/
2479 mcs51_assignRegisters (eBBlock ** ebbs, int count)
2484 setToNull ((void *) &_G.funcrUsed);
2485 mcs51_ptrRegReq = _G.stackExtend = _G.dataExtend = 0;
2488 /* change assignments this will remove some
2489 live ranges reducing some register pressure */
2490 for (i = 0; i < count; i++)
2491 packRegisters (ebbs[i]);
2493 if (options.dump_pack)
2494 dumpEbbsToFileExt (DUMP_PACK, ebbs, count);
2496 /* first determine for each live range the number of
2497 registers & the type of registers required for each */
2500 /* and serially allocate registers */
2501 serialRegAssign (ebbs, count);
2503 /* if stack was extended then tell the user */
2506 /* werror(W_TOOMANY_SPILS,"stack", */
2507 /* _G.stackExtend,currFunc->name,""); */
2513 /* werror(W_TOOMANY_SPILS,"data space", */
2514 /* _G.dataExtend,currFunc->name,""); */
2518 /* after that create the register mask
2519 for each of the instruction */
2520 createRegMask (ebbs, count);
2522 /* redo that offsets for stacked automatic variables */
2523 redoStackOffsets ();
2525 if (options.dump_rassgn)
2527 dumpEbbsToFileExt (DUMP_RASSGN, ebbs, count);
2528 dumpLiveRanges (DUMP_LRANGE, liveRanges);
2531 /* do the overlaysegment stuff SDCCmem.c */
2532 doOverlays (ebbs, count);
2534 /* now get back the chain */
2535 ic = iCodeLabelOptimize (iCodeFromeBBlock (ebbs, count));
2539 /* free up any _G.stackSpil locations allocated */
2540 applyToSet (_G.stackSpil, deallocStackSpil);
2542 setToNull ((void **) &_G.stackSpil);
2543 setToNull ((void **) &_G.spiltSet);
2544 /* mark all registers as free */