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 failed which means
1186 this was spilt then break */
1187 if (!sym->regs[j]) {
1189 fprintf (stderr, "%d reg(s) lost in %s:%d\n",
1190 j, __FILE__,__LINE__);
1196 /* if it shares registers with operands make sure
1197 that they are in the same position */
1198 if (IC_LEFT (ic) && IS_SYMOP (IC_LEFT (ic)) &&
1199 OP_SYMBOL (IC_LEFT (ic))->nRegs && ic->op != '=') {
1200 positionRegs (OP_SYMBOL (IC_RESULT (ic)),
1201 OP_SYMBOL (IC_LEFT (ic)), ic->lineno);
1203 /* do the same for the right operand */
1204 if (IC_RIGHT (ic) && IS_SYMOP (IC_RIGHT (ic)) &&
1205 OP_SYMBOL (IC_RIGHT (ic))->nRegs) {
1206 positionRegs (OP_SYMBOL (IC_RESULT (ic)),
1207 OP_SYMBOL (IC_RIGHT (ic)), ic->lineno);
1220 /*-----------------------------------------------------------------*/
1221 /* rUmaskForOp :- returns register mask for an operand */
1222 /*-----------------------------------------------------------------*/
1224 mcs51_rUmaskForOp (operand * op)
1230 /* only temporaries are assigned registers */
1234 sym = OP_SYMBOL (op);
1236 /* if spilt or no registers assigned to it
1238 if (sym->isspilt || !sym->nRegs)
1241 rumask = newBitVect (mcs51_nRegs);
1243 for (j = 0; j < sym->nRegs; j++)
1245 rumask = bitVectSetBit (rumask,
1246 sym->regs[j]->rIdx);
1252 /*-----------------------------------------------------------------*/
1253 /* regsUsedIniCode :- returns bit vector of registers used in iCode */
1254 /*-----------------------------------------------------------------*/
1256 regsUsedIniCode (iCode * ic)
1258 bitVect *rmask = newBitVect (mcs51_nRegs);
1260 /* do the special cases first */
1263 rmask = bitVectUnion (rmask,
1264 mcs51_rUmaskForOp (IC_COND (ic)));
1268 /* for the jumptable */
1269 if (ic->op == JUMPTABLE)
1271 rmask = bitVectUnion (rmask,
1272 mcs51_rUmaskForOp (IC_JTCOND (ic)));
1277 /* of all other cases */
1279 rmask = bitVectUnion (rmask,
1280 mcs51_rUmaskForOp (IC_LEFT (ic)));
1284 rmask = bitVectUnion (rmask,
1285 mcs51_rUmaskForOp (IC_RIGHT (ic)));
1288 rmask = bitVectUnion (rmask,
1289 mcs51_rUmaskForOp (IC_RESULT (ic)));
1295 /*-----------------------------------------------------------------*/
1296 /* createRegMask - for each instruction will determine the regsUsed */
1297 /*-----------------------------------------------------------------*/
1299 createRegMask (eBBlock ** ebbs, int count)
1303 /* for all blocks */
1304 for (i = 0; i < count; i++)
1308 if (ebbs[i]->noPath &&
1309 (ebbs[i]->entryLabel != entryLabel &&
1310 ebbs[i]->entryLabel != returnLabel))
1313 /* for all instructions */
1314 for (ic = ebbs[i]->sch; ic; ic = ic->next)
1319 if (SKIP_IC2 (ic) || !ic->rlive)
1322 /* first mark the registers used in this
1324 ic->rUsed = regsUsedIniCode (ic);
1325 _G.funcrUsed = bitVectUnion (_G.funcrUsed, ic->rUsed);
1327 /* now create the register mask for those
1328 registers that are in use : this is a
1329 super set of ic->rUsed */
1330 ic->rMask = newBitVect (mcs51_nRegs + 1);
1332 /* for all live Ranges alive at this point */
1333 for (j = 1; j < ic->rlive->size; j++)
1338 /* if not alive then continue */
1339 if (!bitVectBitValue (ic->rlive, j))
1342 /* find the live range we are interested in */
1343 if (!(sym = hTabItemWithKey (liveRanges, j)))
1345 werror (E_INTERNAL_ERROR, __FILE__, __LINE__,
1346 "createRegMask cannot find live range");
1350 /* if no register assigned to it */
1351 if (!sym->nRegs || sym->isspilt)
1354 /* for all the registers allocated to it */
1355 for (k = 0; k < sym->nRegs; k++)
1358 bitVectSetBit (ic->rMask, sym->regs[k]->rIdx);
1364 /*-----------------------------------------------------------------*/
1365 /* rematStr - returns the rematerialized string for a remat var */
1366 /*-----------------------------------------------------------------*/
1368 rematStr (symbol * sym)
1371 iCode *ic = sym->rematiCode;
1376 /* if plus or minus print the right hand side */
1377 if (ic->op == '+' || ic->op == '-')
1379 sprintf (s, "0x%04x %c ", (int) operandLitValue (IC_RIGHT (ic)),
1382 ic = OP_SYMBOL (IC_LEFT (ic))->rematiCode;
1386 /* we reached the end */
1387 sprintf (s, "%s", OP_SYMBOL (IC_LEFT (ic))->rname);
1394 /*-----------------------------------------------------------------*/
1395 /* regTypeNum - computes the type & number of registers required */
1396 /*-----------------------------------------------------------------*/
1404 /* for each live range do */
1405 for (sym = hTabFirstItem (liveRanges, &k); sym;
1406 sym = hTabNextItem (liveRanges, &k))
1409 /* if used zero times then no registers needed */
1410 if ((sym->liveTo - sym->liveFrom) == 0)
1414 /* if the live range is a temporary */
1418 /* if the type is marked as a conditional */
1419 if (sym->regType == REG_CND)
1422 /* if used in return only then we don't
1424 if (sym->ruonly || sym->accuse)
1426 if (IS_AGGREGATE (sym->type) || sym->isptr)
1427 sym->type = aggrToPtr (sym->type, FALSE);
1431 /* if the symbol has only one definition &
1432 that definition is a get_pointer and the
1433 pointer we are getting is rematerializable and
1436 if (bitVectnBitsOn (sym->defs) == 1 &&
1437 (ic = hTabItemWithKey (iCodehTab,
1438 bitVectFirstBit (sym->defs))) &&
1441 !IS_BITVAR (sym->etype))
1445 /* if remat in data space */
1446 if (OP_SYMBOL (IC_LEFT (ic))->remat &&
1447 DCL_TYPE (aggrToPtr (sym->type, FALSE)) == POINTER)
1450 /* create a psuedo symbol & force a spil */
1451 symbol *psym = newSymbol (rematStr (OP_SYMBOL (IC_LEFT (ic))), 1);
1452 psym->type = sym->type;
1453 psym->etype = sym->etype;
1454 strcpy (psym->rname, psym->name);
1456 sym->usl.spillLoc = psym;
1460 /* if in data space or idata space then try to
1461 allocate pointer register */
1465 /* if not then we require registers */
1466 sym->nRegs = ((IS_AGGREGATE (sym->type) || sym->isptr) ?
1467 getSize (sym->type = aggrToPtr (sym->type, FALSE)) :
1468 getSize (sym->type));
1472 fprintf (stderr, "allocated more than 4 or 0 registers for type ");
1473 printTypeChain (sym->type, stderr);
1474 fprintf (stderr, "\n");
1477 /* determine the type of register required */
1478 if (sym->nRegs == 1 &&
1479 IS_PTR (sym->type) &&
1481 sym->regType = REG_PTR;
1483 sym->regType = REG_GPR;
1487 /* for the first run we don't provide */
1488 /* registers for true symbols we will */
1489 /* see how things go */
1495 /*-----------------------------------------------------------------*/
1496 /* freeAllRegs - mark all registers as free */
1497 /*-----------------------------------------------------------------*/
1503 for (i = 0; i < mcs51_nRegs; i++)
1504 regs8051[i].isFree = 1;
1507 /*-----------------------------------------------------------------*/
1508 /* deallocStackSpil - this will set the stack pointer back */
1509 /*-----------------------------------------------------------------*/
1511 DEFSETFUNC (deallocStackSpil)
1519 /*-----------------------------------------------------------------*/
1520 /* farSpacePackable - returns the packable icode for far variables */
1521 /*-----------------------------------------------------------------*/
1523 farSpacePackable (iCode * ic)
1527 /* go thru till we find a definition for the
1528 symbol on the right */
1529 for (dic = ic->prev; dic; dic = dic->prev)
1531 /* if the definition is a call then no */
1532 if ((dic->op == CALL || dic->op == PCALL) &&
1533 IC_RESULT (dic)->key == IC_RIGHT (ic)->key)
1538 /* if shift by unknown amount then not */
1539 if ((dic->op == LEFT_OP || dic->op == RIGHT_OP) &&
1540 IC_RESULT (dic)->key == IC_RIGHT (ic)->key)
1543 /* if pointer get and size > 1 */
1544 if (POINTER_GET (dic) &&
1545 getSize (aggrToPtr (operandType (IC_LEFT (dic)), FALSE)) > 1)
1548 if (POINTER_SET (dic) &&
1549 getSize (aggrToPtr (operandType (IC_RESULT (dic)), FALSE)) > 1)
1552 /* if any three is a true symbol in far space */
1553 if (IC_RESULT (dic) &&
1554 IS_TRUE_SYMOP (IC_RESULT (dic)) &&
1555 isOperandInFarSpace (IC_RESULT (dic)))
1558 if (IC_RIGHT (dic) &&
1559 IS_TRUE_SYMOP (IC_RIGHT (dic)) &&
1560 isOperandInFarSpace (IC_RIGHT (dic)) &&
1561 !isOperandEqual (IC_RIGHT (dic), IC_RESULT (ic)))
1564 if (IC_LEFT (dic) &&
1565 IS_TRUE_SYMOP (IC_LEFT (dic)) &&
1566 isOperandInFarSpace (IC_LEFT (dic)) &&
1567 !isOperandEqual (IC_LEFT (dic), IC_RESULT (ic)))
1570 if (isOperandEqual (IC_RIGHT (ic), IC_RESULT (dic)))
1572 if ((dic->op == LEFT_OP ||
1573 dic->op == RIGHT_OP ||
1575 IS_OP_LITERAL (IC_RIGHT (dic)))
1585 /*-----------------------------------------------------------------*/
1586 /* packRegsForAssign - register reduction for assignment */
1587 /*-----------------------------------------------------------------*/
1589 packRegsForAssign (iCode * ic, eBBlock * ebp)
1592 //sym_link *etype = operandType (IC_RIGHT (ic));
1594 if (!IS_ITEMP (IC_RIGHT (ic)) ||
1595 OP_SYMBOL (IC_RIGHT (ic))->isind ||
1596 OP_LIVETO (IC_RIGHT (ic)) > ic->seq
1597 /* why? || IS_BITFIELD (etype) */ )
1602 /* if the true symbol is defined in far space or on stack
1603 then we should not since this will increase register pressure */
1604 if (isOperandInFarSpace(IC_RESULT(ic)) && !farSpacePackable(ic)) {
1608 /* find the definition of iTempNN scanning backwards if we find a
1609 a use of the true symbol in before we find the definition then
1611 for (dic = ic->prev; dic; dic = dic->prev)
1613 /* if there is a function call then don't pack it */
1614 if ((dic->op == CALL || dic->op == PCALL))
1623 if (IS_TRUE_SYMOP (IC_RESULT (dic)) &&
1624 IS_OP_VOLATILE (IC_RESULT (dic)))
1630 if (IS_SYMOP (IC_RESULT (dic)) &&
1631 IC_RESULT (dic)->key == IC_RIGHT (ic)->key)
1633 if (POINTER_SET (dic))
1639 if (IS_SYMOP (IC_RIGHT (dic)) &&
1640 (IC_RIGHT (dic)->key == IC_RESULT (ic)->key ||
1641 IC_RIGHT (dic)->key == IC_RIGHT (ic)->key))
1647 if (IS_SYMOP (IC_LEFT (dic)) &&
1648 (IC_LEFT (dic)->key == IC_RESULT (ic)->key ||
1649 IC_LEFT (dic)->key == IC_RIGHT (ic)->key))
1655 if (POINTER_SET (dic) &&
1656 IC_RESULT (dic)->key == IC_RESULT (ic)->key)
1664 return 0; /* did not find */
1666 /* if assignment then check that right is not a bit */
1667 if (ASSIGNMENT (dic) && !POINTER_SET (dic))
1669 sym_link *etype = operandType (IC_RIGHT (dic));
1670 if (IS_BITFIELD (etype))
1673 /* if the result is on stack or iaccess then it must be
1674 the same atleast one of the operands */
1675 if (OP_SYMBOL (IC_RESULT (ic))->onStack ||
1676 OP_SYMBOL (IC_RESULT (ic))->iaccess)
1679 /* the operation has only one symbol
1680 operator then we can pack */
1681 if ((IC_LEFT (dic) && !IS_SYMOP (IC_LEFT (dic))) ||
1682 (IC_RIGHT (dic) && !IS_SYMOP (IC_RIGHT (dic))))
1685 if (!((IC_LEFT (dic) &&
1686 IC_RESULT (ic)->key == IC_LEFT (dic)->key) ||
1688 IC_RESULT (ic)->key == IC_RIGHT (dic)->key)))
1692 /* found the definition */
1693 /* replace the result with the result of */
1694 /* this assignment and remove this assignment */
1695 IC_RESULT (dic) = IC_RESULT (ic);
1697 if (IS_ITEMP (IC_RESULT (dic)) && OP_SYMBOL (IC_RESULT (dic))->liveFrom > dic->seq)
1699 OP_SYMBOL (IC_RESULT (dic))->liveFrom = dic->seq;
1701 /* delete from liverange table also
1702 delete from all the points inbetween and the new
1704 for (sic = dic; sic != ic; sic = sic->next)
1706 bitVectUnSetBit (sic->rlive, IC_RESULT (ic)->key);
1707 if (IS_ITEMP (IC_RESULT (dic)))
1708 bitVectSetBit (sic->rlive, IC_RESULT (dic)->key);
1711 remiCodeFromeBBlock (ebp, ic);
1712 hTabDeleteItem (&iCodehTab, ic->key, ic, DELETE_ITEM, NULL);
1713 OP_DEFS (IC_RESULT (dic)) = bitVectSetBit (OP_DEFS (IC_RESULT (dic)), dic->key);
1718 /*-----------------------------------------------------------------*/
1719 /* findAssignToSym : scanning backwards looks for first assig found */
1720 /*-----------------------------------------------------------------*/
1722 findAssignToSym (operand * op, iCode * ic)
1726 for (dic = ic->prev; dic; dic = dic->prev)
1729 /* if definition by assignment */
1730 if (dic->op == '=' &&
1731 !POINTER_SET (dic) &&
1732 IC_RESULT (dic)->key == op->key
1733 /* && IS_TRUE_SYMOP(IC_RIGHT(dic)) */
1737 /* we are interested only if defined in far space */
1738 /* or in stack space in case of + & - */
1740 /* if assigned to a non-symbol then return
1742 if (!IS_SYMOP (IC_RIGHT (dic)))
1745 /* if the symbol is in far space then
1747 if (isOperandInFarSpace (IC_RIGHT (dic)))
1750 /* for + & - operations make sure that
1751 if it is on the stack it is the same
1752 as one of the three operands */
1753 if ((ic->op == '+' || ic->op == '-') &&
1754 OP_SYMBOL (IC_RIGHT (dic))->onStack)
1757 if (IC_RESULT (ic)->key != IC_RIGHT (dic)->key &&
1758 IC_LEFT (ic)->key != IC_RIGHT (dic)->key &&
1759 IC_RIGHT (ic)->key != IC_RIGHT (dic)->key)
1767 /* if we find an usage then we cannot delete it */
1768 if (IC_LEFT (dic) && IC_LEFT (dic)->key == op->key)
1771 if (IC_RIGHT (dic) && IC_RIGHT (dic)->key == op->key)
1774 if (POINTER_SET (dic) && IC_RESULT (dic)->key == op->key)
1778 /* now make sure that the right side of dic
1779 is not defined between ic & dic */
1782 iCode *sic = dic->next;
1784 for (; sic != ic; sic = sic->next)
1785 if (IC_RESULT (sic) &&
1786 IC_RESULT (sic)->key == IC_RIGHT (dic)->key)
1795 /*-----------------------------------------------------------------*/
1796 /* packRegsForSupport :- reduce some registers for support calls */
1797 /*-----------------------------------------------------------------*/
1799 packRegsForSupport (iCode * ic, eBBlock * ebp)
1804 /* for the left & right operand :- look to see if the
1805 left was assigned a true symbol in far space in that
1806 case replace them */
1808 if (IS_ITEMP (IC_LEFT (ic)) &&
1809 OP_SYMBOL (IC_LEFT (ic))->liveTo <= ic->seq)
1811 dic = findAssignToSym (IC_LEFT (ic), ic);
1816 /* found it we need to remove it from the
1818 for (sic = dic; sic != ic; sic = sic->next)
1819 bitVectUnSetBit (sic->rlive, IC_LEFT (ic)->key);
1821 OP_SYMBOL(IC_LEFT (ic))=OP_SYMBOL(IC_RIGHT (dic));
1822 IC_LEFT (ic)->key = OP_SYMBOL(IC_RIGHT (dic))->key;
1823 remiCodeFromeBBlock (ebp, dic);
1824 hTabDeleteItem (&iCodehTab, dic->key, dic, DELETE_ITEM, NULL);
1828 /* do the same for the right operand */
1831 IS_ITEMP (IC_RIGHT (ic)) &&
1832 OP_SYMBOL (IC_RIGHT (ic))->liveTo <= ic->seq)
1834 iCode *dic = findAssignToSym (IC_RIGHT (ic), ic);
1840 /* if this is a subtraction & the result
1841 is a true symbol in far space then don't pack */
1842 if (ic->op == '-' && IS_TRUE_SYMOP (IC_RESULT (dic)))
1844 sym_link *etype = getSpec (operandType (IC_RESULT (dic)));
1845 if (IN_FARSPACE (SPEC_OCLS (etype)))
1848 /* found it we need to remove it from the
1850 for (sic = dic; sic != ic; sic = sic->next)
1851 bitVectUnSetBit (sic->rlive, IC_RIGHT (ic)->key);
1853 IC_RIGHT (ic)->operand.symOperand =
1854 IC_RIGHT (dic)->operand.symOperand;
1855 IC_RIGHT (ic)->key = IC_RIGHT (dic)->operand.symOperand->key;
1857 remiCodeFromeBBlock (ebp, dic);
1858 hTabDeleteItem (&iCodehTab, dic->key, dic, DELETE_ITEM, NULL);
1865 #define IS_OP_RUONLY(x) (x && IS_SYMOP(x) && OP_SYMBOL(x)->ruonly)
1868 /*-----------------------------------------------------------------*/
1869 /* packRegsForOneuse : - will reduce some registers for single Use */
1870 /*-----------------------------------------------------------------*/
1872 packRegsForOneuse (iCode * ic, operand * op, eBBlock * ebp)
1877 /* if returning a literal then do nothing */
1881 /* only upto 2 bytes since we cannot predict
1882 the usage of b, & acc */
1883 if (getSize (operandType (op)) > (fReturnSizeMCS51 - 2))
1886 if (ic->op != RETURN &&
1888 !POINTER_SET (ic) &&
1892 /* this routine will mark the a symbol as used in one
1893 instruction use only && if the defintion is local
1894 (ie. within the basic block) && has only one definition &&
1895 that definiion is either a return value from a
1896 function or does not contain any variables in
1898 uses = bitVectCopy (OP_USES (op));
1899 bitVectUnSetBit (uses, ic->key); /* take away this iCode */
1900 if (!bitVectIsZero (uses)) /* has other uses */
1903 /* if it has only one defintion */
1904 if (bitVectnBitsOn (OP_DEFS (op)) > 1)
1905 return NULL; /* has more than one definition */
1907 /* get that definition */
1909 hTabItemWithKey (iCodehTab,
1910 bitVectFirstBit (OP_DEFS (op)))))
1913 /* if that only usage is a cast */
1914 if (dic->op == CAST) {
1915 /* to a bigger type */
1916 if (getSize(OP_SYM_TYPE(IC_RESULT(dic))) >
1917 getSize(OP_SYM_TYPE(IC_RIGHT(dic)))) {
1918 /* than we can not, since we cannot predict the usage of b & acc */
1923 /* found the definition now check if it is local */
1924 if (dic->seq < ebp->fSeq ||
1925 dic->seq > ebp->lSeq)
1926 return NULL; /* non-local */
1928 /* now check if it is the return from
1930 if (dic->op == CALL || dic->op == PCALL)
1932 if (ic->op != SEND && ic->op != RETURN)
1934 OP_SYMBOL (op)->ruonly = 1;
1941 /* otherwise check that the definition does
1942 not contain any symbols in far space */
1943 if (isOperandInFarSpace (IC_LEFT (dic)) ||
1944 isOperandInFarSpace (IC_RIGHT (dic)) ||
1945 IS_OP_RUONLY (IC_LEFT (ic)) ||
1946 IS_OP_RUONLY (IC_RIGHT (ic)))
1951 /* if pointer set then make sure the pointer
1953 if (POINTER_SET (dic) &&
1954 !IS_DATA_PTR (aggrToPtr (operandType (IC_RESULT (dic)), FALSE)))
1957 if (POINTER_GET (dic) &&
1958 !IS_DATA_PTR (aggrToPtr (operandType (IC_LEFT (dic)), FALSE)))
1963 /* also make sure the intervenening instructions
1964 don't have any thing in far space */
1965 for (dic = dic->next; dic && dic != ic && sic != ic; dic = dic->next)
1968 /* if there is an intervening function call then no */
1969 if (dic->op == CALL || dic->op == PCALL)
1971 /* if pointer set then make sure the pointer
1973 if (POINTER_SET (dic) &&
1974 !IS_DATA_PTR (aggrToPtr (operandType (IC_RESULT (dic)), FALSE)))
1977 if (POINTER_GET (dic) &&
1978 !IS_DATA_PTR (aggrToPtr (operandType (IC_LEFT (dic)), FALSE)))
1981 /* if address of & the result is remat the okay */
1982 if (dic->op == ADDRESS_OF &&
1983 OP_SYMBOL (IC_RESULT (dic))->remat)
1986 /* if operand has size of three or more & this
1987 operation is a '*','/' or '%' then 'b' may
1989 if ((dic->op == '%' || dic->op == '/' || dic->op == '*') &&
1990 getSize (operandType (op)) >= 3)
1993 /* if left or right or result is in far space */
1994 if (isOperandInFarSpace (IC_LEFT (dic)) ||
1995 isOperandInFarSpace (IC_RIGHT (dic)) ||
1996 isOperandInFarSpace (IC_RESULT (dic)) ||
1997 IS_OP_RUONLY (IC_LEFT (dic)) ||
1998 IS_OP_RUONLY (IC_RIGHT (dic)) ||
1999 IS_OP_RUONLY (IC_RESULT (dic)))
2003 /* if left or right or result is on stack */
2004 if (isOperandOnStack(IC_LEFT(dic)) ||
2005 isOperandOnStack(IC_RIGHT(dic)) ||
2006 isOperandOnStack(IC_RESULT(dic))) {
2011 OP_SYMBOL (op)->ruonly = 1;
2016 /*-----------------------------------------------------------------*/
2017 /* isBitwiseOptimizable - requirements of JEAN LOUIS VERN */
2018 /*-----------------------------------------------------------------*/
2020 isBitwiseOptimizable (iCode * ic)
2022 sym_link *ltype = getSpec (operandType (IC_LEFT (ic)));
2023 sym_link *rtype = getSpec (operandType (IC_RIGHT (ic)));
2025 /* bitwise operations are considered optimizable
2026 under the following conditions (Jean-Louis VERN)
2038 if (IS_LITERAL(rtype) ||
2039 (IS_BITVAR (ltype) && IN_BITSPACE (SPEC_OCLS (ltype))))
2045 /*-----------------------------------------------------------------*/
2046 /* packRegsForAccUse - pack registers for acc use */
2047 /*-----------------------------------------------------------------*/
2049 packRegsForAccUse (iCode * ic)
2053 /* if + or - then it has to be one byte result */
2054 if ((ic->op == '+' || ic->op == '-')
2055 && getSize (operandType (IC_RESULT (ic))) > 1)
2058 /* if shift operation make sure right side is not a literal */
2059 if (ic->op == RIGHT_OP &&
2060 (isOperandLiteral (IC_RIGHT (ic)) ||
2061 getSize (operandType (IC_RESULT (ic))) > 1))
2064 if (ic->op == LEFT_OP &&
2065 (isOperandLiteral (IC_RIGHT (ic)) ||
2066 getSize (operandType (IC_RESULT (ic))) > 1))
2069 if (IS_BITWISE_OP (ic) &&
2070 getSize (operandType (IC_RESULT (ic))) > 1)
2074 /* has only one definition */
2075 if (bitVectnBitsOn (OP_DEFS (IC_RESULT (ic))) > 1)
2078 /* has only one use */
2079 if (bitVectnBitsOn (OP_USES (IC_RESULT (ic))) > 1)
2082 /* and the usage immediately follows this iCode */
2083 if (!(uic = hTabItemWithKey (iCodehTab,
2084 bitVectFirstBit (OP_USES (IC_RESULT (ic))))))
2087 if (ic->next != uic)
2090 /* if it is a conditional branch then we definitely can */
2094 if (uic->op == JUMPTABLE)
2097 /* if the usage is not is an assignment
2098 or an arithmetic / bitwise / shift operation then not */
2099 if (POINTER_SET (uic) &&
2100 getSize (aggrToPtr (operandType (IC_RESULT (uic)), FALSE)) > 1)
2103 if (uic->op != '=' &&
2104 !IS_ARITHMETIC_OP (uic) &&
2105 !IS_BITWISE_OP (uic) &&
2106 uic->op != LEFT_OP &&
2107 uic->op != RIGHT_OP)
2110 /* if used in ^ operation then make sure right is not a
2112 if (uic->op == '^' && isOperandLiteral (IC_RIGHT (uic)))
2115 /* if shift operation make sure right side is not a literal */
2116 if (uic->op == RIGHT_OP &&
2117 (isOperandLiteral (IC_RIGHT (uic)) ||
2118 getSize (operandType (IC_RESULT (uic))) > 1))
2121 if (uic->op == LEFT_OP &&
2122 (isOperandLiteral (IC_RIGHT (uic)) ||
2123 getSize (operandType (IC_RESULT (uic))) > 1))
2126 /* make sure that the result of this icode is not on the
2127 stack, since acc is used to compute stack offset */
2128 if (IS_TRUE_SYMOP (IC_RESULT (uic)) &&
2129 OP_SYMBOL (IC_RESULT (uic))->onStack)
2132 /* if either one of them in far space then we cannot */
2133 if ((IS_TRUE_SYMOP (IC_LEFT (uic)) &&
2134 isOperandInFarSpace (IC_LEFT (uic))) ||
2135 (IS_TRUE_SYMOP (IC_RIGHT (uic)) &&
2136 isOperandInFarSpace (IC_RIGHT (uic))))
2139 /* if the usage has only one operand then we can */
2140 if (IC_LEFT (uic) == NULL ||
2141 IC_RIGHT (uic) == NULL)
2144 /* make sure this is on the left side if not
2145 a '+' since '+' is commutative */
2146 if (ic->op != '+' &&
2147 IC_LEFT (uic)->key != IC_RESULT (ic)->key)
2151 // this is too dangerous and need further restrictions
2154 /* if one of them is a literal then we can */
2155 if ((IC_LEFT (uic) && IS_OP_LITERAL (IC_LEFT (uic))) ||
2156 (IC_RIGHT (uic) && IS_OP_LITERAL (IC_RIGHT (uic))))
2158 OP_SYMBOL (IC_RESULT (ic))->accuse = 1;
2163 /* if the other one is not on stack then we can */
2164 if (IC_LEFT (uic)->key == IC_RESULT (ic)->key &&
2165 (IS_ITEMP (IC_RIGHT (uic)) ||
2166 (IS_TRUE_SYMOP (IC_RIGHT (uic)) &&
2167 !OP_SYMBOL (IC_RIGHT (uic))->onStack)))
2170 if (IC_RIGHT (uic)->key == IC_RESULT (ic)->key &&
2171 (IS_ITEMP (IC_LEFT (uic)) ||
2172 (IS_TRUE_SYMOP (IC_LEFT (uic)) &&
2173 !OP_SYMBOL (IC_LEFT (uic))->onStack)))
2179 OP_SYMBOL (IC_RESULT (ic))->accuse = 1;
2184 /*-----------------------------------------------------------------*/
2185 /* packForPush - hueristics to reduce iCode for pushing */
2186 /*-----------------------------------------------------------------*/
2188 packForPush (iCode * ic, eBBlock * ebp)
2193 if (ic->op != IPUSH || !IS_ITEMP (IC_LEFT (ic)))
2196 /* must have only definition & one usage */
2197 if (bitVectnBitsOn (OP_DEFS (IC_LEFT (ic))) != 1 ||
2198 bitVectnBitsOn (OP_USES (IC_LEFT (ic))) != 1)
2201 /* find the definition */
2202 if (!(dic = hTabItemWithKey (iCodehTab,
2203 bitVectFirstBit (OP_DEFS (IC_LEFT (ic))))))
2206 if (dic->op != '=' || POINTER_SET (dic))
2209 /* make sure the right side does not have any definitions
2211 dbv = OP_DEFS(IC_RIGHT(dic));
2212 for (lic = ic; lic && lic != dic ; lic = lic->prev) {
2213 if (bitVectBitValue(dbv,lic->key))
2216 /* make sure they have the same type */
2218 sym_link *itype=operandType(IC_LEFT(ic));
2219 sym_link *ditype=operandType(IC_RIGHT(dic));
2221 if (SPEC_USIGN(itype)!=SPEC_USIGN(ditype) ||
2222 SPEC_LONG(itype)!=SPEC_LONG(ditype))
2225 /* extend the live range of replaced operand if needed */
2226 if (OP_SYMBOL(IC_RIGHT(dic))->liveTo < ic->seq) {
2227 OP_SYMBOL(IC_RIGHT(dic))->liveTo = ic->seq;
2229 /* we now we know that it has one & only one def & use
2230 and the that the definition is an assignment */
2231 IC_LEFT (ic) = IC_RIGHT (dic);
2233 remiCodeFromeBBlock (ebp, dic);
2234 hTabDeleteItem (&iCodehTab, dic->key, dic, DELETE_ITEM, NULL);
2237 /*-----------------------------------------------------------------*/
2238 /* packRegisters - does some transformations to reduce register */
2240 /*-----------------------------------------------------------------*/
2242 packRegisters (eBBlock * ebp)
2252 /* look for assignments of the form */
2253 /* iTempNN = TRueSym (someoperation) SomeOperand */
2255 /* TrueSym := iTempNN:1 */
2256 for (ic = ebp->sch; ic; ic = ic->next)
2258 /* find assignment of the form TrueSym := iTempNN:1 */
2259 if (ic->op == '=' && !POINTER_SET (ic))
2260 change += packRegsForAssign (ic, ebp);
2267 for (ic = ebp->sch; ic; ic = ic->next)
2269 /* if this is an itemp & result of an address of a true sym
2270 then mark this as rematerialisable */
2271 if (ic->op == ADDRESS_OF &&
2272 IS_ITEMP (IC_RESULT (ic)) &&
2273 IS_TRUE_SYMOP (IC_LEFT (ic)) &&
2274 bitVectnBitsOn (OP_DEFS (IC_RESULT (ic))) == 1 &&
2275 !OP_SYMBOL (IC_LEFT (ic))->onStack)
2278 OP_SYMBOL (IC_RESULT (ic))->remat = 1;
2279 OP_SYMBOL (IC_RESULT (ic))->rematiCode = ic;
2280 OP_SYMBOL (IC_RESULT (ic))->usl.spillLoc = NULL;
2284 /* if straight assignment then carry remat flag if
2285 this is the only definition */
2286 if (ic->op == '=' &&
2287 !POINTER_SET (ic) &&
2288 IS_SYMOP (IC_RIGHT (ic)) &&
2289 OP_SYMBOL (IC_RIGHT (ic))->remat &&
2290 bitVectnBitsOn (OP_SYMBOL (IC_RESULT (ic))->defs) <= 1)
2293 OP_SYMBOL (IC_RESULT (ic))->remat =
2294 OP_SYMBOL (IC_RIGHT (ic))->remat;
2295 OP_SYMBOL (IC_RESULT (ic))->rematiCode =
2296 OP_SYMBOL (IC_RIGHT (ic))->rematiCode;
2299 /* if this is a +/- operation with a rematerizable
2300 then mark this as rematerializable as well */
2301 if ((ic->op == '+' || ic->op == '-') &&
2302 (IS_SYMOP (IC_LEFT (ic)) &&
2303 IS_ITEMP (IC_RESULT (ic)) &&
2304 OP_SYMBOL (IC_LEFT (ic))->remat &&
2305 bitVectnBitsOn (OP_DEFS (IC_RESULT (ic))) == 1 &&
2306 IS_OP_LITERAL (IC_RIGHT (ic))))
2308 OP_SYMBOL (IC_RESULT (ic))->remat = 1;
2309 OP_SYMBOL (IC_RESULT (ic))->rematiCode = ic;
2310 OP_SYMBOL (IC_RESULT (ic))->usl.spillLoc = NULL;
2313 /* mark the pointer usages */
2314 if (POINTER_SET (ic))
2315 OP_SYMBOL (IC_RESULT (ic))->uptr = 1;
2317 if (POINTER_GET (ic))
2318 OP_SYMBOL (IC_LEFT (ic))->uptr = 1;
2322 /* if we are using a symbol on the stack
2323 then we should say mcs51_ptrRegReq */
2324 if (ic->op == IFX && IS_SYMOP (IC_COND (ic)))
2325 mcs51_ptrRegReq += ((OP_SYMBOL (IC_COND (ic))->onStack ||
2326 OP_SYMBOL (IC_COND (ic))->iaccess) ? 1 : 0);
2327 else if (ic->op == JUMPTABLE && IS_SYMOP (IC_JTCOND (ic)))
2328 mcs51_ptrRegReq += ((OP_SYMBOL (IC_JTCOND (ic))->onStack ||
2329 OP_SYMBOL (IC_JTCOND (ic))->iaccess) ? 1 : 0);
2332 if (IS_SYMOP (IC_LEFT (ic)))
2333 mcs51_ptrRegReq += ((OP_SYMBOL (IC_LEFT (ic))->onStack ||
2334 OP_SYMBOL (IC_LEFT (ic))->iaccess) ? 1 : 0);
2335 if (IS_SYMOP (IC_RIGHT (ic)))
2336 mcs51_ptrRegReq += ((OP_SYMBOL (IC_RIGHT (ic))->onStack ||
2337 OP_SYMBOL (IC_RIGHT (ic))->iaccess) ? 1 : 0);
2338 if (IS_SYMOP (IC_RESULT (ic)))
2339 mcs51_ptrRegReq += ((OP_SYMBOL (IC_RESULT (ic))->onStack ||
2340 OP_SYMBOL (IC_RESULT (ic))->iaccess) ? 1 : 0);
2344 /* if the condition of an if instruction
2345 is defined in the previous instruction and
2346 this is the only usage then
2347 mark the itemp as a conditional */
2348 if ((IS_CONDITIONAL (ic) ||
2349 (IS_BITWISE_OP(ic) && isBitwiseOptimizable (ic))) &&
2350 ic->next && ic->next->op == IFX &&
2351 bitVectnBitsOn (OP_USES(IC_RESULT(ic)))==1 &&
2352 isOperandEqual (IC_RESULT (ic), IC_COND (ic->next)) &&
2353 OP_SYMBOL (IC_RESULT (ic))->liveTo <= ic->next->seq)
2355 OP_SYMBOL (IC_RESULT (ic))->regType = REG_CND;
2359 /* reduce for support function calls */
2360 if (ic->supportRtn || ic->op == '+' || ic->op == '-')
2361 packRegsForSupport (ic, ebp);
2363 /* some cases the redundant moves can
2364 can be eliminated for return statements */
2365 if ((ic->op == RETURN || ic->op == SEND) &&
2366 !isOperandInFarSpace (IC_LEFT (ic)) &&
2367 options.model == MODEL_SMALL) {
2368 if (0 && options.stackAuto) {
2369 /* we should check here if acc will be clobbered for stack
2370 offset calculations */
2372 packRegsForOneuse (ic, IC_LEFT (ic), ebp);
2376 /* if pointer set & left has a size more than
2377 one and right is not in far space */
2378 if (POINTER_SET (ic) &&
2379 !isOperandInFarSpace (IC_RIGHT (ic)) &&
2380 !OP_SYMBOL (IC_RESULT (ic))->remat &&
2381 !IS_OP_RUONLY (IC_RIGHT (ic)) &&
2382 getSize (aggrToPtr (operandType (IC_RESULT (ic)), FALSE)) > 1)
2384 packRegsForOneuse (ic, IC_RESULT (ic), ebp);
2386 /* if pointer get */
2387 if (POINTER_GET (ic) &&
2388 !isOperandInFarSpace (IC_RESULT (ic)) &&
2389 !OP_SYMBOL (IC_LEFT (ic))->remat &&
2390 !IS_OP_RUONLY (IC_RESULT (ic)) &&
2391 getSize (aggrToPtr (operandType (IC_LEFT (ic)), FALSE)) > 1)
2393 packRegsForOneuse (ic, IC_LEFT (ic), ebp);
2396 /* if this is cast for intergral promotion then
2397 check if only use of the definition of the
2398 operand being casted/ if yes then replace
2399 the result of that arithmetic operation with
2400 this result and get rid of the cast */
2403 sym_link *fromType = operandType (IC_RIGHT (ic));
2404 sym_link *toType = operandType (IC_LEFT (ic));
2406 if (IS_INTEGRAL (fromType) && IS_INTEGRAL (toType) &&
2407 getSize (fromType) != getSize (toType) &&
2408 SPEC_USIGN (fromType) == SPEC_USIGN (toType))
2411 iCode *dic = packRegsForOneuse (ic, IC_RIGHT (ic), ebp);
2414 if (IS_ARITHMETIC_OP (dic))
2416 IC_RESULT (dic) = IC_RESULT (ic);
2417 remiCodeFromeBBlock (ebp, ic);
2418 hTabDeleteItem (&iCodehTab, ic->key, ic, DELETE_ITEM, NULL);
2419 OP_DEFS (IC_RESULT (dic)) = bitVectSetBit (OP_DEFS (IC_RESULT (dic)), dic->key);
2423 OP_SYMBOL (IC_RIGHT (ic))->ruonly = 0;
2429 /* if the type from and type to are the same
2430 then if this is the only use then packit */
2431 if (compareType (operandType (IC_RIGHT (ic)),
2432 operandType (IC_LEFT (ic))) == 1)
2434 iCode *dic = packRegsForOneuse (ic, IC_RIGHT (ic), ebp);
2437 IC_RESULT (dic) = IC_RESULT (ic);
2438 remiCodeFromeBBlock (ebp, ic);
2439 hTabDeleteItem (&iCodehTab, ic->key, ic, DELETE_ITEM, NULL);
2440 OP_DEFS (IC_RESULT (dic)) = bitVectSetBit (OP_DEFS (IC_RESULT (dic)), dic->key);
2448 iTempNN := (some variable in farspace) V1
2453 if (ic->op == IPUSH)
2455 packForPush (ic, ebp);
2459 /* pack registers for accumulator use, when the
2460 result of an arithmetic or bit wise operation
2461 has only one use, that use is immediately following
2462 the defintion and the using iCode has only one
2463 operand or has two operands but one is literal &
2464 the result of that operation is not on stack then
2465 we can leave the result of this operation in acc:b
2467 if ((IS_ARITHMETIC_OP (ic)
2468 || IS_CONDITIONAL(ic)
2469 || IS_BITWISE_OP (ic)
2470 || ic->op == LEFT_OP || ic->op == RIGHT_OP
2471 || (ic->op == ADDRESS_OF && isOperandOnStack (IC_LEFT (ic)))
2473 IS_ITEMP (IC_RESULT (ic)) &&
2474 getSize (operandType (IC_RESULT (ic))) <= 2)
2476 packRegsForAccUse (ic);
2480 /*-----------------------------------------------------------------*/
2481 /* assignRegisters - assigns registers to each live range as need */
2482 /*-----------------------------------------------------------------*/
2484 mcs51_assignRegisters (eBBlock ** ebbs, int count)
2489 setToNull ((void *) &_G.funcrUsed);
2490 mcs51_ptrRegReq = _G.stackExtend = _G.dataExtend = 0;
2493 /* change assignments this will remove some
2494 live ranges reducing some register pressure */
2495 for (i = 0; i < count; i++)
2496 packRegisters (ebbs[i]);
2498 if (options.dump_pack)
2499 dumpEbbsToFileExt (DUMP_PACK, ebbs, count);
2501 /* first determine for each live range the number of
2502 registers & the type of registers required for each */
2505 /* and serially allocate registers */
2506 serialRegAssign (ebbs, count);
2508 /* if stack was extended then tell the user */
2511 /* werror(W_TOOMANY_SPILS,"stack", */
2512 /* _G.stackExtend,currFunc->name,""); */
2518 /* werror(W_TOOMANY_SPILS,"data space", */
2519 /* _G.dataExtend,currFunc->name,""); */
2523 /* after that create the register mask
2524 for each of the instruction */
2525 createRegMask (ebbs, count);
2527 /* redo that offsets for stacked automatic variables */
2528 redoStackOffsets ();
2530 if (options.dump_rassgn)
2532 dumpEbbsToFileExt (DUMP_RASSGN, ebbs, count);
2533 dumpLiveRanges (DUMP_LRANGE, liveRanges);
2536 /* do the overlaysegment stuff SDCCmem.c */
2537 doOverlays (ebbs, count);
2539 /* now get back the chain */
2540 ic = iCodeLabelOptimize (iCodeFromeBBlock (ebbs, count));
2544 /* free up any _G.stackSpil locations allocated */
2545 applyToSet (_G.stackSpil, deallocStackSpil);
2547 setToNull ((void **) &_G.stackSpil);
2548 setToNull ((void **) &_G.spiltSet);
2549 /* mark all registers as free */