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 (bitVectBitValue(sym->clashes,fsym->key)) return 0;
402 /*-----------------------------------------------------------------*/
403 /* isFree - will return 1 if the a free spil location is found */
404 /*-----------------------------------------------------------------*/
409 V_ARG (symbol **, sloc);
410 V_ARG (symbol *, fsym);
412 /* if already found */
416 /* if it is free && and the itmp assigned to
417 this does not have any overlapping live ranges
418 with the one currently being assigned and
419 the size can be accomodated */
421 noOverLap (sym->usl.itmpStack, fsym) &&
422 getSize (sym->type) >= getSize (fsym->type))
431 /*-----------------------------------------------------------------*/
432 /* spillLRWithPtrReg :- will spil those live ranges which use PTR */
433 /*-----------------------------------------------------------------*/
435 spillLRWithPtrReg (symbol * forSym)
441 if (!_G.regAssigned ||
442 bitVectIsZero (_G.regAssigned))
445 r0 = mcs51_regWithIdx (R0_IDX);
446 r1 = mcs51_regWithIdx (R1_IDX);
448 /* for all live ranges */
449 for (lrsym = hTabFirstItem (liveRanges, &k); lrsym;
450 lrsym = hTabNextItem (liveRanges, &k))
454 /* if no registers assigned to it or spilt */
455 /* if it does not overlap with this then
456 not need to spill it */
458 if (lrsym->isspilt || !lrsym->nRegs ||
459 (lrsym->liveTo < forSym->liveFrom))
462 /* go thru the registers : if it is either
463 r0 or r1 then spil it */
464 for (j = 0; j < lrsym->nRegs; j++)
465 if (lrsym->regs[j] == r0 ||
466 lrsym->regs[j] == r1)
475 /*-----------------------------------------------------------------*/
476 /* createStackSpil - create a location on the stack to spil */
477 /*-----------------------------------------------------------------*/
479 createStackSpil (symbol * sym)
482 int useXstack, model;
486 /* first go try and find a free one that is already
487 existing on the stack */
488 if (applyToSet (_G.stackSpil, isFree, &sloc, sym))
490 /* found a free one : just update & return */
491 sym->usl.spillLoc = sloc;
494 addSetHead (&sloc->usl.itmpStack, sym);
498 /* could not then have to create one , this is the hard part
499 we need to allocate this on the stack : this is really a
500 hack!! but cannot think of anything better at this time */
502 if (sprintf (slocBuffer, "sloc%d", _G.slocNum++) >= sizeof (slocBuffer))
504 fprintf (stderr, "***Internal error: slocBuffer overflowed: %s:%d\n",
509 sloc = newiTemp (slocBuffer);
511 /* set the type to the spilling symbol */
512 sloc->type = copyLinkChain (sym->type);
513 sloc->etype = getSpec (sloc->type);
514 SPEC_SCLS (sloc->etype) = S_DATA;
515 SPEC_EXTR (sloc->etype) = 0;
516 SPEC_STAT (sloc->etype) = 0;
518 /* we don't allow it to be allocated`
519 onto the external stack since : so we
520 temporarily turn it off ; we also
521 turn off memory model to prevent
522 the spil from going to the external storage
525 useXstack = options.useXstack;
526 model = options.model;
527 /* noOverlay = options.noOverlay; */
528 /* options.noOverlay = 1; */
529 options.model = options.useXstack = 0;
533 options.useXstack = useXstack;
534 options.model = model;
535 /* options.noOverlay = noOverlay; */
536 sloc->isref = 1; /* to prevent compiler warning */
538 /* if it is on the stack then update the stack */
539 if (IN_STACK (sloc->etype))
541 currFunc->stack += getSize (sloc->type);
542 _G.stackExtend += getSize (sloc->type);
545 _G.dataExtend += getSize (sloc->type);
547 /* add it to the _G.stackSpil set */
548 addSetHead (&_G.stackSpil, sloc);
549 sym->usl.spillLoc = sloc;
552 /* add it to the set of itempStack set
553 of the spill location */
554 addSetHead (&sloc->usl.itmpStack, sym);
558 /*-----------------------------------------------------------------*/
559 /* isSpiltOnStack - returns true if the spil location is on stack */
560 /*-----------------------------------------------------------------*/
562 isSpiltOnStack (symbol * sym)
572 /* if (sym->_G.stackSpil) */
575 if (!sym->usl.spillLoc)
578 etype = getSpec (sym->usl.spillLoc->type);
579 if (IN_STACK (etype))
585 /*-----------------------------------------------------------------*/
586 /* spillThis - spils a specific operand */
587 /*-----------------------------------------------------------------*/
589 spillThis (symbol * sym)
592 /* if this is rematerializable or has a spillLocation
593 we are okay, else we need to create a spillLocation
595 if (!(sym->remat || sym->usl.spillLoc))
596 createStackSpil (sym);
599 /* mark it has spilt & put it in the spilt set */
601 _G.spiltSet = bitVectSetBit (_G.spiltSet, sym->key);
603 bitVectUnSetBit (_G.regAssigned, sym->key);
605 for (i = 0; i < sym->nRegs; i++)
609 freeReg (sym->regs[i]);
613 /* if spilt on stack then free up r0 & r1
614 if they could have been assigned to some
616 if (!mcs51_ptrRegReq && isSpiltOnStack (sym))
619 spillLRWithPtrReg (sym);
622 if (sym->usl.spillLoc && !sym->remat)
623 sym->usl.spillLoc->allocreq = 1;
627 /*-----------------------------------------------------------------*/
628 /* selectSpil - select a iTemp to spil : rather a simple procedure */
629 /*-----------------------------------------------------------------*/
631 selectSpil (iCode * ic, eBBlock * ebp, symbol * forSym)
633 bitVect *lrcs = NULL;
637 /* get the spillable live ranges */
638 lrcs = computeSpillable (ic);
640 /* get all live ranges that are rematerizable */
641 if ((selectS = liveRangesWith (lrcs, rematable, ebp, ic)))
644 /* return the least used of these */
645 return leastUsedLR (selectS);
648 /* get live ranges with spillLocations in direct space */
649 if ((selectS = liveRangesWith (lrcs, directSpilLoc, ebp, ic)))
651 sym = leastUsedLR (selectS);
652 strcpy (sym->rname, (sym->usl.spillLoc->rname[0] ?
653 sym->usl.spillLoc->rname :
654 sym->usl.spillLoc->name));
656 /* mark it as allocation required */
657 sym->usl.spillLoc->allocreq = 1;
661 /* if the symbol is local to the block then */
662 if (forSym->liveTo < ebp->lSeq)
665 /* check if there are any live ranges allocated
666 to registers that are not used in this block */
667 if (!_G.blockSpil && (selectS = liveRangesWith (lrcs, notUsedInBlock, ebp, ic)))
669 sym = leastUsedLR (selectS);
670 /* if this is not rematerializable */
679 /* check if there are any live ranges that not
680 used in the remainder of the block */
681 if (!_G.blockSpil && (selectS = liveRangesWith (lrcs, notUsedInRemaining, ebp, ic)))
683 sym = leastUsedLR (selectS);
696 /* find live ranges with spillocation && not used as pointers */
697 if ((selectS = liveRangesWith (lrcs, hasSpilLocnoUptr, ebp, ic)))
700 sym = leastUsedLR (selectS);
701 /* mark this as allocation required */
702 sym->usl.spillLoc->allocreq = 1;
706 /* find live ranges with spillocation */
707 if ((selectS = liveRangesWith (lrcs, hasSpilLoc, ebp, ic)))
710 sym = leastUsedLR (selectS);
711 sym->usl.spillLoc->allocreq = 1;
715 /* couldn't find then we need to create a spil
716 location on the stack , for which one? the least
718 if ((selectS = liveRangesWith (lrcs, noSpilLoc, ebp, ic)))
721 /* return a created spil location */
722 sym = createStackSpil (leastUsedLR (selectS));
723 sym->usl.spillLoc->allocreq = 1;
727 /* this is an extreme situation we will spill
728 this one : happens very rarely but it does happen */
734 /*-----------------------------------------------------------------*/
735 /* spilSomething - spil some variable & mark registers as free */
736 /*-----------------------------------------------------------------*/
738 spilSomething (iCode * ic, eBBlock * ebp, symbol * forSym)
743 /* get something we can spil */
744 ssym = selectSpil (ic, ebp, forSym);
746 /* mark it as spilt */
748 _G.spiltSet = bitVectSetBit (_G.spiltSet, ssym->key);
750 /* mark it as not register assigned &
751 take it away from the set */
752 bitVectUnSetBit (_G.regAssigned, ssym->key);
754 /* mark the registers as free */
755 for (i = 0; i < ssym->nRegs; i++)
757 freeReg (ssym->regs[i]);
759 /* if spilt on stack then free up r0 & r1
760 if they could have been assigned to as gprs */
761 if (!mcs51_ptrRegReq && isSpiltOnStack (ssym))
764 spillLRWithPtrReg (ssym);
767 /* if this was a block level spil then insert push & pop
768 at the start & end of block respectively */
771 iCode *nic = newiCode (IPUSH, operandFromSymbol (ssym), NULL);
772 /* add push to the start of the block */
773 addiCodeToeBBlock (ebp, nic, (ebp->sch->op == LABEL ?
774 ebp->sch->next : ebp->sch));
775 nic = newiCode (IPOP, operandFromSymbol (ssym), NULL);
776 /* add pop to the end of the block */
777 addiCodeToeBBlock (ebp, nic, NULL);
780 /* if spilt because not used in the remainder of the
781 block then add a push before this instruction and
782 a pop at the end of the block */
783 if (ssym->remainSpil)
786 iCode *nic = newiCode (IPUSH, operandFromSymbol (ssym), NULL);
787 /* add push just before this instruction */
788 addiCodeToeBBlock (ebp, nic, ic);
790 nic = newiCode (IPOP, operandFromSymbol (ssym), NULL);
791 /* add pop to the end of the block */
792 addiCodeToeBBlock (ebp, nic, NULL);
801 /*-----------------------------------------------------------------*/
802 /* getRegPtr - will try for PTR if not a GPR type if not spil */
803 /*-----------------------------------------------------------------*/
805 getRegPtr (iCode * ic, eBBlock * ebp, symbol * sym)
810 /* try for a ptr type */
811 if ((reg = allocReg (REG_PTR)))
814 /* try for gpr type */
815 if ((reg = allocReg (REG_GPR)))
818 /* we have to spil */
819 if (!spilSomething (ic, ebp, sym))
822 /* this looks like an infinite loop but
823 in really selectSpil will abort */
827 /*-----------------------------------------------------------------*/
828 /* getRegGpr - will try for GPR if not spil */
829 /*-----------------------------------------------------------------*/
831 getRegGpr (iCode * ic, eBBlock * ebp, symbol * sym)
836 /* try for gpr type */
837 if ((reg = allocReg (REG_GPR)))
840 if (!mcs51_ptrRegReq)
841 if ((reg = allocReg (REG_PTR)))
844 /* we have to spil */
845 if (!spilSomething (ic, ebp, sym))
848 /* this looks like an infinite loop but
849 in really selectSpil will abort */
853 /*-----------------------------------------------------------------*/
854 /* symHasReg - symbol has a given register */
855 /*-----------------------------------------------------------------*/
857 symHasReg (symbol * sym, regs * reg)
861 for (i = 0; i < sym->nRegs; i++)
862 if (sym->regs[i] == reg)
868 /*-----------------------------------------------------------------*/
869 /* deassignLRs - check the live to and if they have registers & are */
870 /* not spilt then free up the registers */
871 /*-----------------------------------------------------------------*/
873 deassignLRs (iCode * ic, eBBlock * ebp)
879 for (sym = hTabFirstItem (liveRanges, &k); sym;
880 sym = hTabNextItem (liveRanges, &k))
884 /* if it does not end here */
885 if (sym->liveTo > ic->seq)
888 /* if it was spilt on stack then we can
889 mark the stack spil location as free */
894 sym->usl.spillLoc->isFree = 1;
900 if (!bitVectBitValue (_G.regAssigned, sym->key))
903 /* special case check if this is an IFX &
904 the privious one was a pop and the
905 previous one was not spilt then keep track
907 if (ic->op == IFX && ic->prev &&
908 ic->prev->op == IPOP &&
909 !ic->prev->parmPush &&
910 !OP_SYMBOL (IC_LEFT (ic->prev))->isspilt)
911 psym = OP_SYMBOL (IC_LEFT (ic->prev));
917 bitVectUnSetBit (_G.regAssigned, sym->key);
919 /* if the result of this one needs registers
920 and does not have it then assign it right
922 if (IC_RESULT (ic) &&
923 !(SKIP_IC2 (ic) || /* not a special icode */
924 ic->op == JUMPTABLE ||
930 (result = OP_SYMBOL (IC_RESULT (ic))) && /* has a result */
931 result->liveTo > ic->seq && /* and will live beyond this */
932 result->liveTo <= ebp->lSeq && /* does not go beyond this block */
933 result->regType == sym->regType && /* same register types */
934 result->nRegs && /* which needs registers */
935 !result->isspilt && /* and does not already have them */
937 !bitVectBitValue (_G.regAssigned, result->key) &&
938 /* the number of free regs + number of regs in this LR
939 can accomodate the what result Needs */
940 ((nfreeRegsType (result->regType) +
941 sym->nRegs) >= result->nRegs)
945 for (i = 0; i < result->nRegs; i++)
947 result->regs[i] = sym->regs[i];
949 result->regs[i] = getRegGpr (ic, ebp, result);
951 _G.regAssigned = bitVectSetBit (_G.regAssigned, result->key);
955 /* free the remaining */
956 for (; i < sym->nRegs; i++)
960 if (!symHasReg (psym, sym->regs[i]))
961 freeReg (sym->regs[i]);
964 freeReg (sym->regs[i]);
971 /*-----------------------------------------------------------------*/
972 /* reassignLR - reassign this to registers */
973 /*-----------------------------------------------------------------*/
975 reassignLR (operand * op)
977 symbol *sym = OP_SYMBOL (op);
980 /* not spilt any more */
981 sym->isspilt = sym->blockSpil = sym->remainSpil = 0;
982 bitVectUnSetBit (_G.spiltSet, sym->key);
984 _G.regAssigned = bitVectSetBit (_G.regAssigned, sym->key);
988 for (i = 0; i < sym->nRegs; i++)
989 sym->regs[i]->isFree = 0;
992 /*-----------------------------------------------------------------*/
993 /* willCauseSpill - determines if allocating will cause a spill */
994 /*-----------------------------------------------------------------*/
996 willCauseSpill (int nr, int rt)
998 /* first check if there are any avlb registers
999 of te type required */
1002 /* special case for pointer type
1003 if pointer type not avlb then
1004 check for type gpr */
1005 if (nFreeRegs (rt) >= nr)
1007 if (nFreeRegs (REG_GPR) >= nr)
1012 if (mcs51_ptrRegReq)
1014 if (nFreeRegs (rt) >= nr)
1019 if (nFreeRegs (REG_PTR) +
1020 nFreeRegs (REG_GPR) >= nr)
1025 /* it will cause a spil */
1029 /*-----------------------------------------------------------------*/
1030 /* positionRegs - the allocator can allocate same registers to res- */
1031 /* ult and operand, if this happens make sure they are in the same */
1032 /* position as the operand otherwise chaos results */
1033 /*-----------------------------------------------------------------*/
1035 positionRegs (symbol * result, symbol * opsym, int lineno)
1037 int count = min (result->nRegs, opsym->nRegs);
1038 int i, j = 0, shared = 0;
1040 /* if the result has been spilt then cannot share */
1045 /* first make sure that they actually share */
1046 for (i = 0; i < count; i++)
1048 for (j = 0; j < count; j++)
1050 if (result->regs[i] == opsym->regs[j] && i != j)
1060 regs *tmp = result->regs[i];
1061 result->regs[i] = result->regs[j];
1062 result->regs[j] = tmp;
1067 /*-----------------------------------------------------------------*/
1068 /* serialRegAssign - serially allocate registers to the variables */
1069 /*-----------------------------------------------------------------*/
1071 serialRegAssign (eBBlock ** ebbs, int count)
1075 /* for all blocks */
1076 for (i = 0; i < count; i++) {
1080 if (ebbs[i]->noPath &&
1081 (ebbs[i]->entryLabel != entryLabel &&
1082 ebbs[i]->entryLabel != returnLabel))
1085 /* of all instructions do */
1086 for (ic = ebbs[i]->sch; ic; ic = ic->next) {
1088 /* if this is an ipop that means some live
1089 range will have to be assigned again */
1091 reassignLR (IC_LEFT (ic));
1093 /* if result is present && is a true symbol */
1094 if (IC_RESULT (ic) && ic->op != IFX &&
1095 IS_TRUE_SYMOP (IC_RESULT (ic)))
1096 OP_SYMBOL (IC_RESULT (ic))->allocreq = 1;
1098 /* take away registers from live
1099 ranges that end at this instruction */
1100 deassignLRs (ic, ebbs[i]);
1102 /* some don't need registers */
1103 if (SKIP_IC2 (ic) ||
1104 ic->op == JUMPTABLE ||
1108 (IC_RESULT (ic) && POINTER_SET (ic)))
1111 /* now we need to allocate registers
1112 only for the result */
1113 if (IC_RESULT (ic)) {
1114 symbol *sym = OP_SYMBOL (IC_RESULT (ic));
1120 /* if it does not need or is spilt
1121 or is already assigned to registers
1122 or will not live beyond this instructions */
1125 bitVectBitValue (_G.regAssigned, sym->key) ||
1126 sym->liveTo <= ic->seq)
1129 /* if some liverange has been spilt at the block level
1130 and this one live beyond this block then spil this
1132 if (_G.blockSpil && sym->liveTo > ebbs[i]->lSeq) {
1136 /* if trying to allocate this will cause
1137 a spill and there is nothing to spill
1138 or this one is rematerializable then
1140 willCS = willCauseSpill (sym->nRegs, sym->regType);
1141 spillable = computeSpillable (ic);
1142 if (sym->remat || (willCS && bitVectIsZero (spillable))) {
1147 /* if it has a spillocation & is used less than
1148 all other live ranges then spill this */
1150 if (sym->usl.spillLoc) {
1151 symbol *leastUsed = leastUsedLR (liveRangesWith (spillable,
1152 allLRs, ebbs[i], ic));
1153 if (leastUsed && leastUsed->used > sym->used) {
1158 /* if none of the liveRanges have a spillLocation then better
1159 to spill this one than anything else already assigned to registers */
1160 if (liveRangesWith(spillable,noSpilLoc,ebbs[i],ic)) {
1166 /* if we need ptr regs for the right side
1168 if (POINTER_GET (ic) && IS_SYMOP (IC_LEFT (ic))
1169 && getSize (OP_SYMBOL (IC_LEFT (ic))->type) <= (unsigned int) PTRSIZE) {
1173 /* else we assign registers to it */
1174 _G.regAssigned = bitVectSetBit (_G.regAssigned, sym->key);
1176 for (j = 0; j < sym->nRegs; j++) {
1177 if (sym->regType == REG_PTR)
1178 sym->regs[j] = getRegPtr (ic, ebbs[i], sym);
1180 sym->regs[j] = getRegGpr (ic, ebbs[i], sym);
1182 /* if the allocation failed which means
1183 this was spilt then break */
1184 if (!sym->regs[j]) {
1186 fprintf (stderr, "%d reg(s) lost in %s:%d\n",
1187 j, __FILE__,__LINE__);
1193 /* if it shares registers with operands make sure
1194 that they are in the same position */
1195 if (IC_LEFT (ic) && IS_SYMOP (IC_LEFT (ic)) &&
1196 OP_SYMBOL (IC_LEFT (ic))->nRegs && ic->op != '=') {
1197 positionRegs (OP_SYMBOL (IC_RESULT (ic)),
1198 OP_SYMBOL (IC_LEFT (ic)), ic->lineno);
1200 /* do the same for the right operand */
1201 if (IC_RIGHT (ic) && IS_SYMOP (IC_RIGHT (ic)) &&
1202 OP_SYMBOL (IC_RIGHT (ic))->nRegs) {
1203 positionRegs (OP_SYMBOL (IC_RESULT (ic)),
1204 OP_SYMBOL (IC_RIGHT (ic)), ic->lineno);
1217 /*-----------------------------------------------------------------*/
1218 /* rUmaskForOp :- returns register mask for an operand */
1219 /*-----------------------------------------------------------------*/
1221 mcs51_rUmaskForOp (operand * op)
1227 /* only temporaries are assigned registers */
1231 sym = OP_SYMBOL (op);
1233 /* if spilt or no registers assigned to it
1235 if (sym->isspilt || !sym->nRegs)
1238 rumask = newBitVect (mcs51_nRegs);
1240 for (j = 0; j < sym->nRegs; j++)
1242 rumask = bitVectSetBit (rumask,
1243 sym->regs[j]->rIdx);
1249 /*-----------------------------------------------------------------*/
1250 /* regsUsedIniCode :- returns bit vector of registers used in iCode */
1251 /*-----------------------------------------------------------------*/
1253 regsUsedIniCode (iCode * ic)
1255 bitVect *rmask = newBitVect (mcs51_nRegs);
1257 /* do the special cases first */
1260 rmask = bitVectUnion (rmask,
1261 mcs51_rUmaskForOp (IC_COND (ic)));
1265 /* for the jumptable */
1266 if (ic->op == JUMPTABLE)
1268 rmask = bitVectUnion (rmask,
1269 mcs51_rUmaskForOp (IC_JTCOND (ic)));
1274 /* of all other cases */
1276 rmask = bitVectUnion (rmask,
1277 mcs51_rUmaskForOp (IC_LEFT (ic)));
1281 rmask = bitVectUnion (rmask,
1282 mcs51_rUmaskForOp (IC_RIGHT (ic)));
1285 rmask = bitVectUnion (rmask,
1286 mcs51_rUmaskForOp (IC_RESULT (ic)));
1292 /*-----------------------------------------------------------------*/
1293 /* createRegMask - for each instruction will determine the regsUsed */
1294 /*-----------------------------------------------------------------*/
1296 createRegMask (eBBlock ** ebbs, int count)
1300 /* for all blocks */
1301 for (i = 0; i < count; i++)
1305 if (ebbs[i]->noPath &&
1306 (ebbs[i]->entryLabel != entryLabel &&
1307 ebbs[i]->entryLabel != returnLabel))
1310 /* for all instructions */
1311 for (ic = ebbs[i]->sch; ic; ic = ic->next)
1316 if (SKIP_IC2 (ic) || !ic->rlive)
1319 /* first mark the registers used in this
1321 ic->rUsed = regsUsedIniCode (ic);
1322 _G.funcrUsed = bitVectUnion (_G.funcrUsed, ic->rUsed);
1324 /* now create the register mask for those
1325 registers that are in use : this is a
1326 super set of ic->rUsed */
1327 ic->rMask = newBitVect (mcs51_nRegs + 1);
1329 /* for all live Ranges alive at this point */
1330 for (j = 1; j < ic->rlive->size; j++)
1335 /* if not alive then continue */
1336 if (!bitVectBitValue (ic->rlive, j))
1339 /* find the live range we are interested in */
1340 if (!(sym = hTabItemWithKey (liveRanges, j)))
1342 werror (E_INTERNAL_ERROR, __FILE__, __LINE__,
1343 "createRegMask cannot find live range");
1347 /* if no register assigned to it */
1348 if (!sym->nRegs || sym->isspilt)
1351 /* for all the registers allocated to it */
1352 for (k = 0; k < sym->nRegs; k++)
1355 bitVectSetBit (ic->rMask, sym->regs[k]->rIdx);
1361 /*-----------------------------------------------------------------*/
1362 /* rematStr - returns the rematerialized string for a remat var */
1363 /*-----------------------------------------------------------------*/
1365 rematStr (symbol * sym)
1368 iCode *ic = sym->rematiCode;
1373 /* if plus or minus print the right hand side */
1374 if (ic->op == '+' || ic->op == '-')
1376 sprintf (s, "0x%04x %c ", (int) operandLitValue (IC_RIGHT (ic)),
1379 ic = OP_SYMBOL (IC_LEFT (ic))->rematiCode;
1383 /* cast then continue */
1384 if (IS_CAST_ICODE(ic)) {
1385 ic = OP_SYMBOL (IC_RIGHT (ic))->rematiCode;
1388 /* we reached the end */
1389 sprintf (s, "%s", OP_SYMBOL (IC_LEFT (ic))->rname);
1396 /*-----------------------------------------------------------------*/
1397 /* regTypeNum - computes the type & number of registers required */
1398 /*-----------------------------------------------------------------*/
1406 /* for each live range do */
1407 for (sym = hTabFirstItem (liveRanges, &k); sym;
1408 sym = hTabNextItem (liveRanges, &k))
1411 /* if used zero times then no registers needed */
1412 if ((sym->liveTo - sym->liveFrom) == 0)
1416 /* if the live range is a temporary */
1420 /* if the type is marked as a conditional */
1421 if (sym->regType == REG_CND)
1424 /* if used in return only then we don't
1426 if (sym->ruonly || sym->accuse)
1428 if (IS_AGGREGATE (sym->type) || sym->isptr)
1429 sym->type = aggrToPtr (sym->type, FALSE);
1433 /* if the symbol has only one definition &
1434 that definition is a get_pointer and the
1435 pointer we are getting is rematerializable and
1438 if (bitVectnBitsOn (sym->defs) == 1 &&
1439 (ic = hTabItemWithKey (iCodehTab,
1440 bitVectFirstBit (sym->defs))) &&
1443 !IS_BITVAR (sym->etype))
1447 /* if remat in data space */
1448 if (OP_SYMBOL (IC_LEFT (ic))->remat &&
1449 !IS_CAST_ICODE(OP_SYMBOL (IC_LEFT (ic))->rematiCode) &&
1450 DCL_TYPE (aggrToPtr (sym->type, FALSE)) == POINTER)
1453 /* create a psuedo symbol & force a spil */
1454 symbol *psym = newSymbol (rematStr (OP_SYMBOL (IC_LEFT (ic))), 1);
1455 psym->type = sym->type;
1456 psym->etype = sym->etype;
1457 strcpy (psym->rname, psym->name);
1459 sym->usl.spillLoc = psym;
1463 /* if in data space or idata space then try to
1464 allocate pointer register */
1468 /* if not then we require registers */
1469 sym->nRegs = ((IS_AGGREGATE (sym->type) || sym->isptr) ?
1470 getSize (sym->type = aggrToPtr (sym->type, FALSE)) :
1471 getSize (sym->type));
1475 fprintf (stderr, "allocated more than 4 or 0 registers for type ");
1476 printTypeChain (sym->type, stderr);
1477 fprintf (stderr, "\n");
1480 /* determine the type of register required */
1481 if (sym->nRegs == 1 &&
1482 IS_PTR (sym->type) &&
1484 sym->regType = REG_PTR;
1486 sym->regType = REG_GPR;
1490 /* for the first run we don't provide */
1491 /* registers for true symbols we will */
1492 /* see how things go */
1498 /*-----------------------------------------------------------------*/
1499 /* freeAllRegs - mark all registers as free */
1500 /*-----------------------------------------------------------------*/
1506 for (i = 0; i < mcs51_nRegs; i++)
1507 regs8051[i].isFree = 1;
1510 /*-----------------------------------------------------------------*/
1511 /* deallocStackSpil - this will set the stack pointer back */
1512 /*-----------------------------------------------------------------*/
1514 DEFSETFUNC (deallocStackSpil)
1522 /*-----------------------------------------------------------------*/
1523 /* farSpacePackable - returns the packable icode for far variables */
1524 /*-----------------------------------------------------------------*/
1526 farSpacePackable (iCode * ic)
1530 /* go thru till we find a definition for the
1531 symbol on the right */
1532 for (dic = ic->prev; dic; dic = dic->prev)
1534 /* if the definition is a call then no */
1535 if ((dic->op == CALL || dic->op == PCALL) &&
1536 IC_RESULT (dic)->key == IC_RIGHT (ic)->key)
1541 /* if shift by unknown amount then not */
1542 if ((dic->op == LEFT_OP || dic->op == RIGHT_OP) &&
1543 IC_RESULT (dic)->key == IC_RIGHT (ic)->key)
1546 /* if pointer get and size > 1 */
1547 if (POINTER_GET (dic) &&
1548 getSize (aggrToPtr (operandType (IC_LEFT (dic)), FALSE)) > 1)
1551 if (POINTER_SET (dic) &&
1552 getSize (aggrToPtr (operandType (IC_RESULT (dic)), FALSE)) > 1)
1555 /* if any three is a true symbol in far space */
1556 if (IC_RESULT (dic) &&
1557 IS_TRUE_SYMOP (IC_RESULT (dic)) &&
1558 isOperandInFarSpace (IC_RESULT (dic)))
1561 if (IC_RIGHT (dic) &&
1562 IS_TRUE_SYMOP (IC_RIGHT (dic)) &&
1563 isOperandInFarSpace (IC_RIGHT (dic)) &&
1564 !isOperandEqual (IC_RIGHT (dic), IC_RESULT (ic)))
1567 if (IC_LEFT (dic) &&
1568 IS_TRUE_SYMOP (IC_LEFT (dic)) &&
1569 isOperandInFarSpace (IC_LEFT (dic)) &&
1570 !isOperandEqual (IC_LEFT (dic), IC_RESULT (ic)))
1573 if (isOperandEqual (IC_RIGHT (ic), IC_RESULT (dic)))
1575 if ((dic->op == LEFT_OP ||
1576 dic->op == RIGHT_OP ||
1578 IS_OP_LITERAL (IC_RIGHT (dic)))
1588 /*-----------------------------------------------------------------*/
1589 /* packRegsForAssign - register reduction for assignment */
1590 /*-----------------------------------------------------------------*/
1592 packRegsForAssign (iCode * ic, eBBlock * ebp)
1595 //sym_link *etype = operandType (IC_RIGHT (ic));
1597 if (!IS_ITEMP (IC_RIGHT (ic)) ||
1598 OP_SYMBOL (IC_RIGHT (ic))->isind ||
1599 OP_LIVETO (IC_RIGHT (ic)) > ic->seq
1600 /* why? || IS_BITFIELD (etype) */ )
1605 /* if the true symbol is defined in far space or on stack
1606 then we should not since this will increase register pressure */
1607 if (isOperandInFarSpace(IC_RESULT(ic)) && !farSpacePackable(ic)) {
1611 /* find the definition of iTempNN scanning backwards if we find a
1612 a use of the true symbol in before we find the definition then
1614 for (dic = ic->prev; dic; dic = dic->prev)
1616 /* if there is a function call then don't pack it */
1617 if ((dic->op == CALL || dic->op == PCALL))
1626 if (IS_TRUE_SYMOP (IC_RESULT (dic)) &&
1627 IS_OP_VOLATILE (IC_RESULT (dic)))
1633 if (IS_SYMOP (IC_RESULT (dic)) &&
1634 IC_RESULT (dic)->key == IC_RIGHT (ic)->key)
1636 if (POINTER_SET (dic))
1642 if (IS_SYMOP (IC_RIGHT (dic)) &&
1643 (IC_RIGHT (dic)->key == IC_RESULT (ic)->key ||
1644 IC_RIGHT (dic)->key == IC_RIGHT (ic)->key))
1650 if (IS_SYMOP (IC_LEFT (dic)) &&
1651 (IC_LEFT (dic)->key == IC_RESULT (ic)->key ||
1652 IC_LEFT (dic)->key == IC_RIGHT (ic)->key))
1658 if (POINTER_SET (dic) &&
1659 IC_RESULT (dic)->key == IC_RESULT (ic)->key)
1667 return 0; /* did not find */
1669 /* if assignment then check that right is not a bit */
1670 if (ASSIGNMENT (dic) && !POINTER_SET (dic))
1672 sym_link *etype = operandType (IC_RIGHT (dic));
1673 if (IS_BITFIELD (etype))
1676 /* if the result is on stack or iaccess then it must be
1677 the same atleast one of the operands */
1678 if (OP_SYMBOL (IC_RESULT (ic))->onStack ||
1679 OP_SYMBOL (IC_RESULT (ic))->iaccess)
1682 /* the operation has only one symbol
1683 operator then we can pack */
1684 if ((IC_LEFT (dic) && !IS_SYMOP (IC_LEFT (dic))) ||
1685 (IC_RIGHT (dic) && !IS_SYMOP (IC_RIGHT (dic))))
1688 if (!((IC_LEFT (dic) &&
1689 IC_RESULT (ic)->key == IC_LEFT (dic)->key) ||
1691 IC_RESULT (ic)->key == IC_RIGHT (dic)->key)))
1695 /* found the definition */
1696 /* replace the result with the result of */
1697 /* this assignment and remove this assignment */
1698 IC_RESULT (dic) = IC_RESULT (ic);
1700 if (IS_ITEMP (IC_RESULT (dic)) && OP_SYMBOL (IC_RESULT (dic))->liveFrom > dic->seq)
1702 OP_SYMBOL (IC_RESULT (dic))->liveFrom = dic->seq;
1704 /* delete from liverange table also
1705 delete from all the points inbetween and the new
1707 for (sic = dic; sic != ic; sic = sic->next)
1709 bitVectUnSetBit (sic->rlive, IC_RESULT (ic)->key);
1710 if (IS_ITEMP (IC_RESULT (dic)))
1711 bitVectSetBit (sic->rlive, IC_RESULT (dic)->key);
1714 remiCodeFromeBBlock (ebp, ic);
1715 hTabDeleteItem (&iCodehTab, ic->key, ic, DELETE_ITEM, NULL);
1716 OP_DEFS (IC_RESULT (dic)) = bitVectSetBit (OP_DEFS (IC_RESULT (dic)), dic->key);
1721 /*-----------------------------------------------------------------*/
1722 /* findAssignToSym : scanning backwards looks for first assig found */
1723 /*-----------------------------------------------------------------*/
1725 findAssignToSym (operand * op, iCode * ic)
1729 for (dic = ic->prev; dic; dic = dic->prev)
1732 /* if definition by assignment */
1733 if (dic->op == '=' &&
1734 !POINTER_SET (dic) &&
1735 IC_RESULT (dic)->key == op->key
1736 /* && IS_TRUE_SYMOP(IC_RIGHT(dic)) */
1740 /* we are interested only if defined in far space */
1741 /* or in stack space in case of + & - */
1743 /* if assigned to a non-symbol then return
1745 if (!IS_SYMOP (IC_RIGHT (dic)))
1748 /* if the symbol is in far space then
1750 if (isOperandInFarSpace (IC_RIGHT (dic)))
1753 /* for + & - operations make sure that
1754 if it is on the stack it is the same
1755 as one of the three operands */
1756 if ((ic->op == '+' || ic->op == '-') &&
1757 OP_SYMBOL (IC_RIGHT (dic))->onStack)
1760 if (IC_RESULT (ic)->key != IC_RIGHT (dic)->key &&
1761 IC_LEFT (ic)->key != IC_RIGHT (dic)->key &&
1762 IC_RIGHT (ic)->key != IC_RIGHT (dic)->key)
1770 /* if we find an usage then we cannot delete it */
1771 if (IC_LEFT (dic) && IC_LEFT (dic)->key == op->key)
1774 if (IC_RIGHT (dic) && IC_RIGHT (dic)->key == op->key)
1777 if (POINTER_SET (dic) && IC_RESULT (dic)->key == op->key)
1781 /* now make sure that the right side of dic
1782 is not defined between ic & dic */
1785 iCode *sic = dic->next;
1787 for (; sic != ic; sic = sic->next)
1788 if (IC_RESULT (sic) &&
1789 IC_RESULT (sic)->key == IC_RIGHT (dic)->key)
1798 /*-----------------------------------------------------------------*/
1799 /* packRegsForSupport :- reduce some registers for support calls */
1800 /*-----------------------------------------------------------------*/
1802 packRegsForSupport (iCode * ic, eBBlock * ebp)
1807 /* for the left & right operand :- look to see if the
1808 left was assigned a true symbol in far space in that
1809 case replace them */
1811 if (IS_ITEMP (IC_LEFT (ic)) &&
1812 OP_SYMBOL (IC_LEFT (ic))->liveTo <= ic->seq)
1814 dic = findAssignToSym (IC_LEFT (ic), ic);
1819 /* found it we need to remove it from the
1821 for (sic = dic; sic != ic; sic = sic->next)
1822 bitVectUnSetBit (sic->rlive, IC_LEFT (ic)->key);
1824 OP_SYMBOL(IC_LEFT (ic))=OP_SYMBOL(IC_RIGHT (dic));
1825 IC_LEFT (ic)->key = OP_SYMBOL(IC_RIGHT (dic))->key;
1826 remiCodeFromeBBlock (ebp, dic);
1827 hTabDeleteItem (&iCodehTab, dic->key, dic, DELETE_ITEM, NULL);
1831 /* do the same for the right operand */
1834 IS_ITEMP (IC_RIGHT (ic)) &&
1835 OP_SYMBOL (IC_RIGHT (ic))->liveTo <= ic->seq)
1837 iCode *dic = findAssignToSym (IC_RIGHT (ic), ic);
1843 /* if this is a subtraction & the result
1844 is a true symbol in far space then don't pack */
1845 if (ic->op == '-' && IS_TRUE_SYMOP (IC_RESULT (dic)))
1847 sym_link *etype = getSpec (operandType (IC_RESULT (dic)));
1848 if (IN_FARSPACE (SPEC_OCLS (etype)))
1851 /* found it we need to remove it from the
1853 for (sic = dic; sic != ic; sic = sic->next)
1854 bitVectUnSetBit (sic->rlive, IC_RIGHT (ic)->key);
1856 IC_RIGHT (ic)->operand.symOperand =
1857 IC_RIGHT (dic)->operand.symOperand;
1858 IC_RIGHT (ic)->key = IC_RIGHT (dic)->operand.symOperand->key;
1860 remiCodeFromeBBlock (ebp, dic);
1861 hTabDeleteItem (&iCodehTab, dic->key, dic, DELETE_ITEM, NULL);
1868 #define IS_OP_RUONLY(x) (x && IS_SYMOP(x) && OP_SYMBOL(x)->ruonly)
1871 /*-----------------------------------------------------------------*/
1872 /* packRegsForOneuse : - will reduce some registers for single Use */
1873 /*-----------------------------------------------------------------*/
1875 packRegsForOneuse (iCode * ic, operand * op, eBBlock * ebp)
1880 /* if returning a literal then do nothing */
1884 /* only upto 2 bytes since we cannot predict
1885 the usage of b, & acc */
1886 if (getSize (operandType (op)) > (fReturnSizeMCS51 - 2))
1889 if (ic->op != RETURN &&
1891 !POINTER_SET (ic) &&
1895 /* this routine will mark the a symbol as used in one
1896 instruction use only && if the defintion is local
1897 (ie. within the basic block) && has only one definition &&
1898 that definiion is either a return value from a
1899 function or does not contain any variables in
1901 uses = bitVectCopy (OP_USES (op));
1902 bitVectUnSetBit (uses, ic->key); /* take away this iCode */
1903 if (!bitVectIsZero (uses)) /* has other uses */
1906 /* if it has only one defintion */
1907 if (bitVectnBitsOn (OP_DEFS (op)) > 1)
1908 return NULL; /* has more than one definition */
1910 /* get that definition */
1912 hTabItemWithKey (iCodehTab,
1913 bitVectFirstBit (OP_DEFS (op)))))
1916 /* if that only usage is a cast */
1917 if (dic->op == CAST) {
1918 /* to a bigger type */
1919 if (getSize(OP_SYM_TYPE(IC_RESULT(dic))) >
1920 getSize(OP_SYM_TYPE(IC_RIGHT(dic)))) {
1921 /* than we can not, since we cannot predict the usage of b & acc */
1926 /* found the definition now check if it is local */
1927 if (dic->seq < ebp->fSeq ||
1928 dic->seq > ebp->lSeq)
1929 return NULL; /* non-local */
1931 /* now check if it is the return from
1933 if (dic->op == CALL || dic->op == PCALL)
1935 if (ic->op != SEND && ic->op != RETURN)
1937 OP_SYMBOL (op)->ruonly = 1;
1944 /* otherwise check that the definition does
1945 not contain any symbols in far space */
1946 if (isOperandInFarSpace (IC_LEFT (dic)) ||
1947 isOperandInFarSpace (IC_RIGHT (dic)) ||
1948 IS_OP_RUONLY (IC_LEFT (ic)) ||
1949 IS_OP_RUONLY (IC_RIGHT (ic)))
1954 /* if pointer set then make sure the pointer
1956 if (POINTER_SET (dic) &&
1957 !IS_DATA_PTR (aggrToPtr (operandType (IC_RESULT (dic)), FALSE)))
1960 if (POINTER_GET (dic) &&
1961 !IS_DATA_PTR (aggrToPtr (operandType (IC_LEFT (dic)), FALSE)))
1966 /* also make sure the intervenening instructions
1967 don't have any thing in far space */
1968 for (dic = dic->next; dic && dic != ic && sic != ic; dic = dic->next)
1971 /* if there is an intervening function call then no */
1972 if (dic->op == CALL || dic->op == PCALL)
1974 /* if pointer set then make sure the pointer
1976 if (POINTER_SET (dic) &&
1977 !IS_DATA_PTR (aggrToPtr (operandType (IC_RESULT (dic)), FALSE)))
1980 if (POINTER_GET (dic) &&
1981 !IS_DATA_PTR (aggrToPtr (operandType (IC_LEFT (dic)), FALSE)))
1984 /* if address of & the result is remat the okay */
1985 if (dic->op == ADDRESS_OF &&
1986 OP_SYMBOL (IC_RESULT (dic))->remat)
1989 /* if operand has size of three or more & this
1990 operation is a '*','/' or '%' then 'b' may
1992 if ((dic->op == '%' || dic->op == '/' || dic->op == '*') &&
1993 getSize (operandType (op)) >= 3)
1996 /* if left or right or result is in far space */
1997 if (isOperandInFarSpace (IC_LEFT (dic)) ||
1998 isOperandInFarSpace (IC_RIGHT (dic)) ||
1999 isOperandInFarSpace (IC_RESULT (dic)) ||
2000 IS_OP_RUONLY (IC_LEFT (dic)) ||
2001 IS_OP_RUONLY (IC_RIGHT (dic)) ||
2002 IS_OP_RUONLY (IC_RESULT (dic)))
2006 /* if left or right or result is on stack */
2007 if (isOperandOnStack(IC_LEFT(dic)) ||
2008 isOperandOnStack(IC_RIGHT(dic)) ||
2009 isOperandOnStack(IC_RESULT(dic))) {
2014 OP_SYMBOL (op)->ruonly = 1;
2019 /*-----------------------------------------------------------------*/
2020 /* isBitwiseOptimizable - requirements of JEAN LOUIS VERN */
2021 /*-----------------------------------------------------------------*/
2023 isBitwiseOptimizable (iCode * ic)
2025 sym_link *ltype = getSpec (operandType (IC_LEFT (ic)));
2026 sym_link *rtype = getSpec (operandType (IC_RIGHT (ic)));
2028 /* bitwise operations are considered optimizable
2029 under the following conditions (Jean-Louis VERN)
2041 if (IS_LITERAL(rtype) ||
2042 (IS_BITVAR (ltype) && IN_BITSPACE (SPEC_OCLS (ltype))))
2048 /*-----------------------------------------------------------------*/
2049 /* packRegsForAccUse - pack registers for acc use */
2050 /*-----------------------------------------------------------------*/
2052 packRegsForAccUse (iCode * ic)
2056 /* if + or - then it has to be one byte result */
2057 if ((ic->op == '+' || ic->op == '-')
2058 && getSize (operandType (IC_RESULT (ic))) > 1)
2061 /* if shift operation make sure right side is not a literal */
2062 if (ic->op == RIGHT_OP &&
2063 (isOperandLiteral (IC_RIGHT (ic)) ||
2064 getSize (operandType (IC_RESULT (ic))) > 1))
2067 if (ic->op == LEFT_OP &&
2068 (isOperandLiteral (IC_RIGHT (ic)) ||
2069 getSize (operandType (IC_RESULT (ic))) > 1))
2072 if (IS_BITWISE_OP (ic) &&
2073 getSize (operandType (IC_RESULT (ic))) > 1)
2077 /* has only one definition */
2078 if (bitVectnBitsOn (OP_DEFS (IC_RESULT (ic))) > 1)
2081 /* has only one use */
2082 if (bitVectnBitsOn (OP_USES (IC_RESULT (ic))) > 1)
2085 /* and the usage immediately follows this iCode */
2086 if (!(uic = hTabItemWithKey (iCodehTab,
2087 bitVectFirstBit (OP_USES (IC_RESULT (ic))))))
2090 if (ic->next != uic)
2093 /* if it is a conditional branch then we definitely can */
2097 if (uic->op == JUMPTABLE)
2100 /* if the usage is not is an assignment
2101 or an arithmetic / bitwise / shift operation then not */
2102 if (POINTER_SET (uic) &&
2103 getSize (aggrToPtr (operandType (IC_RESULT (uic)), FALSE)) > 1)
2106 if (uic->op != '=' &&
2107 !IS_ARITHMETIC_OP (uic) &&
2108 !IS_BITWISE_OP (uic) &&
2109 uic->op != LEFT_OP &&
2110 uic->op != RIGHT_OP)
2113 /* if used in ^ operation then make sure right is not a
2115 if (uic->op == '^' && isOperandLiteral (IC_RIGHT (uic)))
2118 /* if shift operation make sure right side is not a literal */
2119 if (uic->op == RIGHT_OP &&
2120 (isOperandLiteral (IC_RIGHT (uic)) ||
2121 getSize (operandType (IC_RESULT (uic))) > 1))
2124 if (uic->op == LEFT_OP &&
2125 (isOperandLiteral (IC_RIGHT (uic)) ||
2126 getSize (operandType (IC_RESULT (uic))) > 1))
2129 /* make sure that the result of this icode is not on the
2130 stack, since acc is used to compute stack offset */
2131 if (IS_TRUE_SYMOP (IC_RESULT (uic)) &&
2132 OP_SYMBOL (IC_RESULT (uic))->onStack)
2135 /* if either one of them in far space then we cannot */
2136 if ((IS_TRUE_SYMOP (IC_LEFT (uic)) &&
2137 isOperandInFarSpace (IC_LEFT (uic))) ||
2138 (IS_TRUE_SYMOP (IC_RIGHT (uic)) &&
2139 isOperandInFarSpace (IC_RIGHT (uic))))
2142 /* if the usage has only one operand then we can */
2143 if (IC_LEFT (uic) == NULL ||
2144 IC_RIGHT (uic) == NULL)
2147 /* make sure this is on the left side if not
2148 a '+' since '+' is commutative */
2149 if (ic->op != '+' &&
2150 IC_LEFT (uic)->key != IC_RESULT (ic)->key)
2154 // this is too dangerous and need further restrictions
2157 /* if one of them is a literal then we can */
2158 if ((IC_LEFT (uic) && IS_OP_LITERAL (IC_LEFT (uic))) ||
2159 (IC_RIGHT (uic) && IS_OP_LITERAL (IC_RIGHT (uic))))
2161 OP_SYMBOL (IC_RESULT (ic))->accuse = 1;
2166 /* if the other one is not on stack then we can */
2167 if (IC_LEFT (uic)->key == IC_RESULT (ic)->key &&
2168 (IS_ITEMP (IC_RIGHT (uic)) ||
2169 (IS_TRUE_SYMOP (IC_RIGHT (uic)) &&
2170 !OP_SYMBOL (IC_RIGHT (uic))->onStack)))
2173 if (IC_RIGHT (uic)->key == IC_RESULT (ic)->key &&
2174 (IS_ITEMP (IC_LEFT (uic)) ||
2175 (IS_TRUE_SYMOP (IC_LEFT (uic)) &&
2176 !OP_SYMBOL (IC_LEFT (uic))->onStack)))
2182 OP_SYMBOL (IC_RESULT (ic))->accuse = 1;
2187 /*-----------------------------------------------------------------*/
2188 /* packForPush - hueristics to reduce iCode for pushing */
2189 /*-----------------------------------------------------------------*/
2191 packForPush (iCode * ic, eBBlock * ebp)
2196 if (ic->op != IPUSH || !IS_ITEMP (IC_LEFT (ic)))
2199 /* must have only definition & one usage */
2200 if (bitVectnBitsOn (OP_DEFS (IC_LEFT (ic))) != 1 ||
2201 bitVectnBitsOn (OP_USES (IC_LEFT (ic))) != 1)
2204 /* find the definition */
2205 if (!(dic = hTabItemWithKey (iCodehTab,
2206 bitVectFirstBit (OP_DEFS (IC_LEFT (ic))))))
2209 if (dic->op != '=' || POINTER_SET (dic))
2212 /* make sure the right side does not have any definitions
2214 dbv = OP_DEFS(IC_RIGHT(dic));
2215 for (lic = ic; lic && lic != dic ; lic = lic->prev) {
2216 if (bitVectBitValue(dbv,lic->key))
2219 /* make sure they have the same type */
2221 sym_link *itype=operandType(IC_LEFT(ic));
2222 sym_link *ditype=operandType(IC_RIGHT(dic));
2224 if (SPEC_USIGN(itype)!=SPEC_USIGN(ditype) ||
2225 SPEC_LONG(itype)!=SPEC_LONG(ditype))
2228 /* extend the live range of replaced operand if needed */
2229 if (OP_SYMBOL(IC_RIGHT(dic))->liveTo < ic->seq) {
2230 OP_SYMBOL(IC_RIGHT(dic))->liveTo = ic->seq;
2232 /* we now we know that it has one & only one def & use
2233 and the that the definition is an assignment */
2234 IC_LEFT (ic) = IC_RIGHT (dic);
2236 remiCodeFromeBBlock (ebp, dic);
2237 hTabDeleteItem (&iCodehTab, dic->key, dic, DELETE_ITEM, NULL);
2240 /*-----------------------------------------------------------------*/
2241 /* packRegisters - does some transformations to reduce register */
2243 /*-----------------------------------------------------------------*/
2245 packRegisters (eBBlock * ebp)
2255 /* look for assignments of the form */
2256 /* iTempNN = TRueSym (someoperation) SomeOperand */
2258 /* TrueSym := iTempNN:1 */
2259 for (ic = ebp->sch; ic; ic = ic->next)
2261 /* find assignment of the form TrueSym := iTempNN:1 */
2262 if (ic->op == '=' && !POINTER_SET (ic))
2263 change += packRegsForAssign (ic, ebp);
2270 for (ic = ebp->sch; ic; ic = ic->next)
2272 /* if this is an itemp & result of an address of a true sym
2273 then mark this as rematerialisable */
2274 if (ic->op == ADDRESS_OF &&
2275 IS_ITEMP (IC_RESULT (ic)) &&
2276 IS_TRUE_SYMOP (IC_LEFT (ic)) &&
2277 bitVectnBitsOn (OP_DEFS (IC_RESULT (ic))) == 1 &&
2278 !OP_SYMBOL (IC_LEFT (ic))->onStack)
2281 OP_SYMBOL (IC_RESULT (ic))->remat = 1;
2282 OP_SYMBOL (IC_RESULT (ic))->rematiCode = ic;
2283 OP_SYMBOL (IC_RESULT (ic))->usl.spillLoc = NULL;
2287 /* if straight assignment then carry remat flag if
2288 this is the only definition */
2289 if (ic->op == '=' &&
2290 !POINTER_SET (ic) &&
2291 IS_SYMOP (IC_RIGHT (ic)) &&
2292 OP_SYMBOL (IC_RIGHT (ic))->remat &&
2293 !IS_CAST_ICODE(OP_SYMBOL (IC_RIGHT (ic))->rematiCode) &&
2294 bitVectnBitsOn (OP_SYMBOL (IC_RESULT (ic))->defs) <= 1)
2297 OP_SYMBOL (IC_RESULT (ic))->remat =
2298 OP_SYMBOL (IC_RIGHT (ic))->remat;
2299 OP_SYMBOL (IC_RESULT (ic))->rematiCode =
2300 OP_SYMBOL (IC_RIGHT (ic))->rematiCode;
2303 /* if cast to a generic pointer & the pointer being
2304 cast is remat, then we can remat this cast as well */
2305 if (ic->op == CAST &&
2306 IS_SYMOP(IC_RIGHT(ic)) &&
2307 OP_SYMBOL(IC_RIGHT(ic))->remat ) {
2308 sym_link *to_type = operandType(IC_LEFT(ic));
2309 sym_link *from_type = operandType(IC_RIGHT(ic));
2310 if (IS_GENPTR(to_type) && IS_PTR(from_type)) {
2311 OP_SYMBOL (IC_RESULT (ic))->remat = 1;
2312 OP_SYMBOL (IC_RESULT (ic))->rematiCode = ic;
2313 OP_SYMBOL (IC_RESULT (ic))->usl.spillLoc = NULL;
2317 /* if this is a +/- operation with a rematerizable
2318 then mark this as rematerializable as well */
2319 if ((ic->op == '+' || ic->op == '-') &&
2320 (IS_SYMOP (IC_LEFT (ic)) &&
2321 IS_ITEMP (IC_RESULT (ic)) &&
2322 IS_OP_LITERAL (IC_RIGHT (ic))) &&
2323 OP_SYMBOL (IC_LEFT (ic))->remat &&
2324 (!IS_SYMOP (IC_RIGHT (ic)) || !IS_CAST_ICODE(OP_SYMBOL (IC_RIGHT (ic))->rematiCode)) &&
2325 bitVectnBitsOn (OP_DEFS (IC_RESULT (ic))) == 1)
2327 OP_SYMBOL (IC_RESULT (ic))->remat = 1;
2328 OP_SYMBOL (IC_RESULT (ic))->rematiCode = ic;
2329 OP_SYMBOL (IC_RESULT (ic))->usl.spillLoc = NULL;
2332 /* mark the pointer usages */
2333 if (POINTER_SET (ic))
2334 OP_SYMBOL (IC_RESULT (ic))->uptr = 1;
2336 if (POINTER_GET (ic))
2337 OP_SYMBOL (IC_LEFT (ic))->uptr = 1;
2341 /* if we are using a symbol on the stack
2342 then we should say mcs51_ptrRegReq */
2343 if (ic->op == IFX && IS_SYMOP (IC_COND (ic)))
2344 mcs51_ptrRegReq += ((OP_SYMBOL (IC_COND (ic))->onStack ||
2345 OP_SYMBOL (IC_COND (ic))->iaccess) ? 1 : 0);
2346 else if (ic->op == JUMPTABLE && IS_SYMOP (IC_JTCOND (ic)))
2347 mcs51_ptrRegReq += ((OP_SYMBOL (IC_JTCOND (ic))->onStack ||
2348 OP_SYMBOL (IC_JTCOND (ic))->iaccess) ? 1 : 0);
2351 if (IS_SYMOP (IC_LEFT (ic)))
2352 mcs51_ptrRegReq += ((OP_SYMBOL (IC_LEFT (ic))->onStack ||
2353 OP_SYMBOL (IC_LEFT (ic))->iaccess) ? 1 : 0);
2354 if (IS_SYMOP (IC_RIGHT (ic)))
2355 mcs51_ptrRegReq += ((OP_SYMBOL (IC_RIGHT (ic))->onStack ||
2356 OP_SYMBOL (IC_RIGHT (ic))->iaccess) ? 1 : 0);
2357 if (IS_SYMOP (IC_RESULT (ic)))
2358 mcs51_ptrRegReq += ((OP_SYMBOL (IC_RESULT (ic))->onStack ||
2359 OP_SYMBOL (IC_RESULT (ic))->iaccess) ? 1 : 0);
2363 /* if the condition of an if instruction
2364 is defined in the previous instruction and
2365 this is the only usage then
2366 mark the itemp as a conditional */
2367 if ((IS_CONDITIONAL (ic) ||
2368 (IS_BITWISE_OP(ic) && isBitwiseOptimizable (ic))) &&
2369 ic->next && ic->next->op == IFX &&
2370 bitVectnBitsOn (OP_USES(IC_RESULT(ic)))==1 &&
2371 isOperandEqual (IC_RESULT (ic), IC_COND (ic->next)) &&
2372 OP_SYMBOL (IC_RESULT (ic))->liveTo <= ic->next->seq)
2374 OP_SYMBOL (IC_RESULT (ic))->regType = REG_CND;
2378 /* reduce for support function calls */
2379 if (ic->supportRtn || ic->op == '+' || ic->op == '-')
2380 packRegsForSupport (ic, ebp);
2382 /* some cases the redundant moves can
2383 can be eliminated for return statements */
2384 if ((ic->op == RETURN || ic->op == SEND) &&
2385 !isOperandInFarSpace (IC_LEFT (ic)) &&
2386 options.model == MODEL_SMALL) {
2387 if (0 && options.stackAuto) {
2388 /* we should check here if acc will be clobbered for stack
2389 offset calculations */
2391 packRegsForOneuse (ic, IC_LEFT (ic), ebp);
2395 /* if pointer set & left has a size more than
2396 one and right is not in far space */
2397 if (POINTER_SET (ic) &&
2398 !isOperandInFarSpace (IC_RIGHT (ic)) &&
2399 !OP_SYMBOL (IC_RESULT (ic))->remat &&
2400 !IS_OP_RUONLY (IC_RIGHT (ic)) &&
2401 getSize (aggrToPtr (operandType (IC_RESULT (ic)), FALSE)) > 1)
2403 packRegsForOneuse (ic, IC_RESULT (ic), ebp);
2405 /* if pointer get */
2406 if (POINTER_GET (ic) &&
2407 !isOperandInFarSpace (IC_RESULT (ic)) &&
2408 !OP_SYMBOL (IC_LEFT (ic))->remat &&
2409 !IS_OP_RUONLY (IC_RESULT (ic)) &&
2410 getSize (aggrToPtr (operandType (IC_LEFT (ic)), FALSE)) > 1)
2412 packRegsForOneuse (ic, IC_LEFT (ic), ebp);
2415 /* if this is cast for intergral promotion then
2416 check if only use of the definition of the
2417 operand being casted/ if yes then replace
2418 the result of that arithmetic operation with
2419 this result and get rid of the cast */
2422 sym_link *fromType = operandType (IC_RIGHT (ic));
2423 sym_link *toType = operandType (IC_LEFT (ic));
2425 if (IS_INTEGRAL (fromType) && IS_INTEGRAL (toType) &&
2426 getSize (fromType) != getSize (toType) &&
2427 SPEC_USIGN (fromType) == SPEC_USIGN (toType))
2430 iCode *dic = packRegsForOneuse (ic, IC_RIGHT (ic), ebp);
2433 if (IS_ARITHMETIC_OP (dic))
2435 IC_RESULT (dic) = IC_RESULT (ic);
2436 remiCodeFromeBBlock (ebp, ic);
2437 hTabDeleteItem (&iCodehTab, ic->key, ic, DELETE_ITEM, NULL);
2438 OP_DEFS (IC_RESULT (dic)) = bitVectSetBit (OP_DEFS (IC_RESULT (dic)), dic->key);
2442 OP_SYMBOL (IC_RIGHT (ic))->ruonly = 0;
2448 /* if the type from and type to are the same
2449 then if this is the only use then packit */
2450 if (compareType (operandType (IC_RIGHT (ic)),
2451 operandType (IC_LEFT (ic))) == 1)
2453 iCode *dic = packRegsForOneuse (ic, IC_RIGHT (ic), ebp);
2456 IC_RESULT (dic) = IC_RESULT (ic);
2457 remiCodeFromeBBlock (ebp, ic);
2458 hTabDeleteItem (&iCodehTab, ic->key, ic, DELETE_ITEM, NULL);
2459 OP_DEFS (IC_RESULT (dic)) = bitVectSetBit (OP_DEFS (IC_RESULT (dic)), dic->key);
2467 iTempNN := (some variable in farspace) V1
2472 if (ic->op == IPUSH)
2474 packForPush (ic, ebp);
2478 /* pack registers for accumulator use, when the
2479 result of an arithmetic or bit wise operation
2480 has only one use, that use is immediately following
2481 the defintion and the using iCode has only one
2482 operand or has two operands but one is literal &
2483 the result of that operation is not on stack then
2484 we can leave the result of this operation in acc:b
2486 if ((IS_ARITHMETIC_OP (ic)
2487 || IS_CONDITIONAL(ic)
2488 || IS_BITWISE_OP (ic)
2489 || ic->op == LEFT_OP || ic->op == RIGHT_OP || ic->op == CALL
2490 || (ic->op == ADDRESS_OF && isOperandOnStack (IC_LEFT (ic)))
2492 IS_ITEMP (IC_RESULT (ic)) &&
2493 getSize (operandType (IC_RESULT (ic))) <= 2)
2495 packRegsForAccUse (ic);
2499 /*-----------------------------------------------------------------*/
2500 /* assignRegisters - assigns registers to each live range as need */
2501 /*-----------------------------------------------------------------*/
2503 mcs51_assignRegisters (eBBlock ** ebbs, int count)
2508 setToNull ((void *) &_G.funcrUsed);
2509 mcs51_ptrRegReq = _G.stackExtend = _G.dataExtend = 0;
2512 /* change assignments this will remove some
2513 live ranges reducing some register pressure */
2514 for (i = 0; i < count; i++)
2515 packRegisters (ebbs[i]);
2517 if (options.dump_pack)
2518 dumpEbbsToFileExt (DUMP_PACK, ebbs, count);
2520 /* first determine for each live range the number of
2521 registers & the type of registers required for each */
2524 /* and serially allocate registers */
2525 serialRegAssign (ebbs, count);
2527 /* if stack was extended then tell the user */
2530 /* werror(W_TOOMANY_SPILS,"stack", */
2531 /* _G.stackExtend,currFunc->name,""); */
2537 /* werror(W_TOOMANY_SPILS,"data space", */
2538 /* _G.dataExtend,currFunc->name,""); */
2542 /* after that create the register mask
2543 for each of the instruction */
2544 createRegMask (ebbs, count);
2546 /* redo that offsets for stacked automatic variables */
2547 redoStackOffsets ();
2549 if (options.dump_rassgn)
2551 dumpEbbsToFileExt (DUMP_RASSGN, ebbs, count);
2552 dumpLiveRanges (DUMP_LRANGE, liveRanges);
2555 /* do the overlaysegment stuff SDCCmem.c */
2556 doOverlays (ebbs, count);
2558 /* now get back the chain */
2559 ic = iCodeLabelOptimize (iCodeFromeBBlock (ebbs, count));
2563 /* free up any _G.stackSpil locations allocated */
2564 applyToSet (_G.stackSpil, deallocStackSpil);
2566 setToNull ((void **) &_G.stackSpil);
2567 setToNull ((void **) &_G.spiltSet);
2568 /* mark all registers as free */