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)) {
1161 /* if this is local to this block then we might find a block spil */
1162 if (!(sym->liveFrom >= ebbs[i]->fSeq && sym->liveTo <= ebbs[i]->lSeq)) {
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 /* cast then continue */
1387 if (IS_CAST_ICODE(ic)) {
1388 ic = OP_SYMBOL (IC_RIGHT (ic))->rematiCode;
1391 /* we reached the end */
1392 sprintf (s, "%s", OP_SYMBOL (IC_LEFT (ic))->rname);
1399 /*-----------------------------------------------------------------*/
1400 /* regTypeNum - computes the type & number of registers required */
1401 /*-----------------------------------------------------------------*/
1403 regTypeNum (eBBlock *ebbs)
1409 /* for each live range do */
1410 for (sym = hTabFirstItem (liveRanges, &k); sym;
1411 sym = hTabNextItem (liveRanges, &k))
1414 /* if used zero times then no registers needed */
1415 if ((sym->liveTo - sym->liveFrom) == 0)
1419 /* if the live range is a temporary */
1423 /* if the type is marked as a conditional */
1424 if (sym->regType == REG_CND)
1427 /* if used in return only then we don't
1429 if (sym->ruonly || sym->accuse)
1431 if (IS_AGGREGATE (sym->type) || sym->isptr)
1432 sym->type = aggrToPtr (sym->type, FALSE);
1436 /* if the symbol has only one definition &
1437 that definition is a get_pointer and the
1438 pointer we are getting is rematerializable and
1441 if (bitVectnBitsOn (sym->defs) == 1 &&
1442 (ic = hTabItemWithKey (iCodehTab,
1443 bitVectFirstBit (sym->defs))) &&
1446 !IS_BITVAR (sym->etype))
1450 /* if remat in data space */
1451 if (OP_SYMBOL (IC_LEFT (ic))->remat &&
1452 !IS_CAST_ICODE(OP_SYMBOL (IC_LEFT (ic))->rematiCode) &&
1453 DCL_TYPE (aggrToPtr (sym->type, FALSE)) == POINTER)
1455 /* create a psuedo symbol & force a spil */
1456 symbol *psym = newSymbol (rematStr (OP_SYMBOL (IC_LEFT (ic))), 1);
1457 psym->type = sym->type;
1458 psym->etype = sym->etype;
1459 strcpy (psym->rname, psym->name);
1461 sym->usl.spillLoc = psym;
1462 #if 0 // an alternative fix for bug #480076
1463 /* now this is a useless assignment to itself */
1464 remiCodeFromeBBlock (ebbs, ic);
1466 /* now this really is an assignment to itself, make it so;
1467 it will be optimized out later */
1469 IC_RIGHT(ic)=IC_RESULT(ic);
1475 /* if in data space or idata space then try to
1476 allocate pointer register */
1480 /* if not then we require registers */
1481 sym->nRegs = ((IS_AGGREGATE (sym->type) || sym->isptr) ?
1482 getSize (sym->type = aggrToPtr (sym->type, FALSE)) :
1483 getSize (sym->type));
1487 fprintf (stderr, "allocated more than 4 or 0 registers for type ");
1488 printTypeChain (sym->type, stderr);
1489 fprintf (stderr, "\n");
1492 /* determine the type of register required */
1493 if (sym->nRegs == 1 &&
1494 IS_PTR (sym->type) &&
1496 sym->regType = REG_PTR;
1498 sym->regType = REG_GPR;
1502 /* for the first run we don't provide */
1503 /* registers for true symbols we will */
1504 /* see how things go */
1510 /*-----------------------------------------------------------------*/
1511 /* freeAllRegs - mark all registers as free */
1512 /*-----------------------------------------------------------------*/
1518 for (i = 0; i < mcs51_nRegs; i++)
1519 regs8051[i].isFree = 1;
1522 /*-----------------------------------------------------------------*/
1523 /* deallocStackSpil - this will set the stack pointer back */
1524 /*-----------------------------------------------------------------*/
1526 DEFSETFUNC (deallocStackSpil)
1534 /*-----------------------------------------------------------------*/
1535 /* farSpacePackable - returns the packable icode for far variables */
1536 /*-----------------------------------------------------------------*/
1538 farSpacePackable (iCode * ic)
1542 /* go thru till we find a definition for the
1543 symbol on the right */
1544 for (dic = ic->prev; dic; dic = dic->prev)
1546 /* if the definition is a call then no */
1547 if ((dic->op == CALL || dic->op == PCALL) &&
1548 IC_RESULT (dic)->key == IC_RIGHT (ic)->key)
1553 /* if shift by unknown amount then not */
1554 if ((dic->op == LEFT_OP || dic->op == RIGHT_OP) &&
1555 IC_RESULT (dic)->key == IC_RIGHT (ic)->key)
1558 /* if pointer get and size > 1 */
1559 if (POINTER_GET (dic) &&
1560 getSize (aggrToPtr (operandType (IC_LEFT (dic)), FALSE)) > 1)
1563 if (POINTER_SET (dic) &&
1564 getSize (aggrToPtr (operandType (IC_RESULT (dic)), FALSE)) > 1)
1567 /* if any three is a true symbol in far space */
1568 if (IC_RESULT (dic) &&
1569 IS_TRUE_SYMOP (IC_RESULT (dic)) &&
1570 isOperandInFarSpace (IC_RESULT (dic)))
1573 if (IC_RIGHT (dic) &&
1574 IS_TRUE_SYMOP (IC_RIGHT (dic)) &&
1575 isOperandInFarSpace (IC_RIGHT (dic)) &&
1576 !isOperandEqual (IC_RIGHT (dic), IC_RESULT (ic)))
1579 if (IC_LEFT (dic) &&
1580 IS_TRUE_SYMOP (IC_LEFT (dic)) &&
1581 isOperandInFarSpace (IC_LEFT (dic)) &&
1582 !isOperandEqual (IC_LEFT (dic), IC_RESULT (ic)))
1585 if (isOperandEqual (IC_RIGHT (ic), IC_RESULT (dic)))
1587 if ((dic->op == LEFT_OP ||
1588 dic->op == RIGHT_OP ||
1590 IS_OP_LITERAL (IC_RIGHT (dic)))
1600 /*-----------------------------------------------------------------*/
1601 /* packRegsForAssign - register reduction for assignment */
1602 /*-----------------------------------------------------------------*/
1604 packRegsForAssign (iCode * ic, eBBlock * ebp)
1607 //sym_link *etype = operandType (IC_RIGHT (ic));
1609 if (!IS_ITEMP (IC_RIGHT (ic)) ||
1610 OP_SYMBOL (IC_RIGHT (ic))->isind ||
1611 OP_LIVETO (IC_RIGHT (ic)) > ic->seq
1612 /* why? || IS_BITFIELD (etype) */ )
1617 /* if the true symbol is defined in far space or on stack
1618 then we should not since this will increase register pressure */
1619 if (isOperandInFarSpace(IC_RESULT(ic)) && !farSpacePackable(ic)) {
1623 /* find the definition of iTempNN scanning backwards if we find a
1624 a use of the true symbol in before we find the definition then
1626 for (dic = ic->prev; dic; dic = dic->prev)
1628 /* if there is a function call then don't pack it */
1629 if ((dic->op == CALL || dic->op == PCALL))
1638 if (IS_TRUE_SYMOP (IC_RESULT (dic)) &&
1639 IS_OP_VOLATILE (IC_RESULT (dic)))
1645 if (IS_SYMOP (IC_RESULT (dic)) &&
1646 IC_RESULT (dic)->key == IC_RIGHT (ic)->key)
1648 if (POINTER_SET (dic))
1654 if (IS_SYMOP (IC_RIGHT (dic)) &&
1655 (IC_RIGHT (dic)->key == IC_RESULT (ic)->key ||
1656 IC_RIGHT (dic)->key == IC_RIGHT (ic)->key))
1662 if (IS_SYMOP (IC_LEFT (dic)) &&
1663 (IC_LEFT (dic)->key == IC_RESULT (ic)->key ||
1664 IC_LEFT (dic)->key == IC_RIGHT (ic)->key))
1670 if (POINTER_SET (dic) &&
1671 IC_RESULT (dic)->key == IC_RESULT (ic)->key)
1679 return 0; /* did not find */
1681 /* if assignment then check that right is not a bit */
1682 if (ASSIGNMENT (dic) && !POINTER_SET (dic))
1684 sym_link *etype = operandType (IC_RIGHT (dic));
1685 if (IS_BITFIELD (etype))
1688 /* if the result is on stack or iaccess then it must be
1689 the same atleast one of the operands */
1690 if (OP_SYMBOL (IC_RESULT (ic))->onStack ||
1691 OP_SYMBOL (IC_RESULT (ic))->iaccess)
1694 /* the operation has only one symbol
1695 operator then we can pack */
1696 if ((IC_LEFT (dic) && !IS_SYMOP (IC_LEFT (dic))) ||
1697 (IC_RIGHT (dic) && !IS_SYMOP (IC_RIGHT (dic))))
1700 if (!((IC_LEFT (dic) &&
1701 IC_RESULT (ic)->key == IC_LEFT (dic)->key) ||
1703 IC_RESULT (ic)->key == IC_RIGHT (dic)->key)))
1707 /* found the definition */
1708 /* replace the result with the result of */
1709 /* this assignment and remove this assignment */
1710 IC_RESULT (dic) = IC_RESULT (ic);
1712 if (IS_ITEMP (IC_RESULT (dic)) && OP_SYMBOL (IC_RESULT (dic))->liveFrom > dic->seq)
1714 OP_SYMBOL (IC_RESULT (dic))->liveFrom = dic->seq;
1716 /* delete from liverange table also
1717 delete from all the points inbetween and the new
1719 for (sic = dic; sic != ic; sic = sic->next)
1721 bitVectUnSetBit (sic->rlive, IC_RESULT (ic)->key);
1722 if (IS_ITEMP (IC_RESULT (dic)))
1723 bitVectSetBit (sic->rlive, IC_RESULT (dic)->key);
1726 remiCodeFromeBBlock (ebp, ic);
1727 hTabDeleteItem (&iCodehTab, ic->key, ic, DELETE_ITEM, NULL);
1728 OP_DEFS (IC_RESULT (dic)) = bitVectSetBit (OP_DEFS (IC_RESULT (dic)), dic->key);
1733 /*-----------------------------------------------------------------*/
1734 /* findAssignToSym : scanning backwards looks for first assig found */
1735 /*-----------------------------------------------------------------*/
1737 findAssignToSym (operand * op, iCode * ic)
1741 for (dic = ic->prev; dic; dic = dic->prev)
1744 /* if definition by assignment */
1745 if (dic->op == '=' &&
1746 !POINTER_SET (dic) &&
1747 IC_RESULT (dic)->key == op->key
1748 /* && IS_TRUE_SYMOP(IC_RIGHT(dic)) */
1752 /* we are interested only if defined in far space */
1753 /* or in stack space in case of + & - */
1755 /* if assigned to a non-symbol then return
1757 if (!IS_SYMOP (IC_RIGHT (dic)))
1760 /* if the symbol is in far space then
1762 if (isOperandInFarSpace (IC_RIGHT (dic)))
1765 /* for + & - operations make sure that
1766 if it is on the stack it is the same
1767 as one of the three operands */
1768 if ((ic->op == '+' || ic->op == '-') &&
1769 OP_SYMBOL (IC_RIGHT (dic))->onStack)
1772 if (IC_RESULT (ic)->key != IC_RIGHT (dic)->key &&
1773 IC_LEFT (ic)->key != IC_RIGHT (dic)->key &&
1774 IC_RIGHT (ic)->key != IC_RIGHT (dic)->key)
1782 /* if we find an usage then we cannot delete it */
1783 if (IC_LEFT (dic) && IC_LEFT (dic)->key == op->key)
1786 if (IC_RIGHT (dic) && IC_RIGHT (dic)->key == op->key)
1789 if (POINTER_SET (dic) && IC_RESULT (dic)->key == op->key)
1793 /* now make sure that the right side of dic
1794 is not defined between ic & dic */
1797 iCode *sic = dic->next;
1799 for (; sic != ic; sic = sic->next)
1800 if (IC_RESULT (sic) &&
1801 IC_RESULT (sic)->key == IC_RIGHT (dic)->key)
1810 /*-----------------------------------------------------------------*/
1811 /* packRegsForSupport :- reduce some registers for support calls */
1812 /*-----------------------------------------------------------------*/
1814 packRegsForSupport (iCode * ic, eBBlock * ebp)
1819 /* for the left & right operand :- look to see if the
1820 left was assigned a true symbol in far space in that
1821 case replace them */
1823 if (IS_ITEMP (IC_LEFT (ic)) &&
1824 OP_SYMBOL (IC_LEFT (ic))->liveTo <= ic->seq)
1826 dic = findAssignToSym (IC_LEFT (ic), ic);
1831 /* found it we need to remove it from the
1833 for (sic = dic; sic != ic; sic = sic->next)
1834 bitVectUnSetBit (sic->rlive, IC_LEFT (ic)->key);
1836 OP_SYMBOL(IC_LEFT (ic))=OP_SYMBOL(IC_RIGHT (dic));
1837 IC_LEFT (ic)->key = OP_SYMBOL(IC_RIGHT (dic))->key;
1838 remiCodeFromeBBlock (ebp, dic);
1839 hTabDeleteItem (&iCodehTab, dic->key, dic, DELETE_ITEM, NULL);
1843 /* do the same for the right operand */
1846 IS_ITEMP (IC_RIGHT (ic)) &&
1847 OP_SYMBOL (IC_RIGHT (ic))->liveTo <= ic->seq)
1849 iCode *dic = findAssignToSym (IC_RIGHT (ic), ic);
1855 /* if this is a subtraction & the result
1856 is a true symbol in far space then don't pack */
1857 if (ic->op == '-' && IS_TRUE_SYMOP (IC_RESULT (dic)))
1859 sym_link *etype = getSpec (operandType (IC_RESULT (dic)));
1860 if (IN_FARSPACE (SPEC_OCLS (etype)))
1863 /* found it we need to remove it from the
1865 for (sic = dic; sic != ic; sic = sic->next)
1866 bitVectUnSetBit (sic->rlive, IC_RIGHT (ic)->key);
1868 IC_RIGHT (ic)->operand.symOperand =
1869 IC_RIGHT (dic)->operand.symOperand;
1870 IC_RIGHT (ic)->key = IC_RIGHT (dic)->operand.symOperand->key;
1872 remiCodeFromeBBlock (ebp, dic);
1873 hTabDeleteItem (&iCodehTab, dic->key, dic, DELETE_ITEM, NULL);
1880 #define IS_OP_RUONLY(x) (x && IS_SYMOP(x) && OP_SYMBOL(x)->ruonly)
1883 /*-----------------------------------------------------------------*/
1884 /* packRegsForOneuse : - will reduce some registers for single Use */
1885 /*-----------------------------------------------------------------*/
1887 packRegsForOneuse (iCode * ic, operand * op, eBBlock * ebp)
1892 /* if returning a literal then do nothing */
1896 /* only upto 2 bytes since we cannot predict
1897 the usage of b, & acc */
1898 if (getSize (operandType (op)) > (fReturnSizeMCS51 - 2))
1901 if (ic->op != RETURN &&
1903 !POINTER_SET (ic) &&
1907 /* this routine will mark the a symbol as used in one
1908 instruction use only && if the defintion is local
1909 (ie. within the basic block) && has only one definition &&
1910 that definiion is either a return value from a
1911 function or does not contain any variables in
1913 uses = bitVectCopy (OP_USES (op));
1914 bitVectUnSetBit (uses, ic->key); /* take away this iCode */
1915 if (!bitVectIsZero (uses)) /* has other uses */
1918 /* if it has only one defintion */
1919 if (bitVectnBitsOn (OP_DEFS (op)) > 1)
1920 return NULL; /* has more than one definition */
1922 /* get that definition */
1924 hTabItemWithKey (iCodehTab,
1925 bitVectFirstBit (OP_DEFS (op)))))
1928 /* if that only usage is a cast */
1929 if (dic->op == CAST) {
1930 /* to a bigger type */
1931 if (getSize(OP_SYM_TYPE(IC_RESULT(dic))) >
1932 getSize(OP_SYM_TYPE(IC_RIGHT(dic)))) {
1933 /* than we can not, since we cannot predict the usage of b & acc */
1938 /* found the definition now check if it is local */
1939 if (dic->seq < ebp->fSeq ||
1940 dic->seq > ebp->lSeq)
1941 return NULL; /* non-local */
1943 /* now check if it is the return from
1945 if (dic->op == CALL || dic->op == PCALL)
1947 if (ic->op != SEND && ic->op != RETURN)
1949 OP_SYMBOL (op)->ruonly = 1;
1956 /* otherwise check that the definition does
1957 not contain any symbols in far space */
1958 if (isOperandInFarSpace (IC_LEFT (dic)) ||
1959 isOperandInFarSpace (IC_RIGHT (dic)) ||
1960 IS_OP_RUONLY (IC_LEFT (ic)) ||
1961 IS_OP_RUONLY (IC_RIGHT (ic)))
1966 /* if pointer set then make sure the pointer
1968 if (POINTER_SET (dic) &&
1969 !IS_DATA_PTR (aggrToPtr (operandType (IC_RESULT (dic)), FALSE)))
1972 if (POINTER_GET (dic) &&
1973 !IS_DATA_PTR (aggrToPtr (operandType (IC_LEFT (dic)), FALSE)))
1978 /* also make sure the intervenening instructions
1979 don't have any thing in far space */
1980 for (dic = dic->next; dic && dic != ic && sic != ic; dic = dic->next)
1983 /* if there is an intervening function call then no */
1984 if (dic->op == CALL || dic->op == PCALL)
1986 /* if pointer set then make sure the pointer
1988 if (POINTER_SET (dic) &&
1989 !IS_DATA_PTR (aggrToPtr (operandType (IC_RESULT (dic)), FALSE)))
1992 if (POINTER_GET (dic) &&
1993 !IS_DATA_PTR (aggrToPtr (operandType (IC_LEFT (dic)), FALSE)))
1996 /* if address of & the result is remat the okay */
1997 if (dic->op == ADDRESS_OF &&
1998 OP_SYMBOL (IC_RESULT (dic))->remat)
2001 /* if operand has size of three or more & this
2002 operation is a '*','/' or '%' then 'b' may
2004 if ((dic->op == '%' || dic->op == '/' || dic->op == '*') &&
2005 getSize (operandType (op)) >= 3)
2008 /* if left or right or result is in far space */
2009 if (isOperandInFarSpace (IC_LEFT (dic)) ||
2010 isOperandInFarSpace (IC_RIGHT (dic)) ||
2011 isOperandInFarSpace (IC_RESULT (dic)) ||
2012 IS_OP_RUONLY (IC_LEFT (dic)) ||
2013 IS_OP_RUONLY (IC_RIGHT (dic)) ||
2014 IS_OP_RUONLY (IC_RESULT (dic)))
2018 /* if left or right or result is on stack */
2019 if (isOperandOnStack(IC_LEFT(dic)) ||
2020 isOperandOnStack(IC_RIGHT(dic)) ||
2021 isOperandOnStack(IC_RESULT(dic))) {
2026 OP_SYMBOL (op)->ruonly = 1;
2031 /*-----------------------------------------------------------------*/
2032 /* isBitwiseOptimizable - requirements of JEAN LOUIS VERN */
2033 /*-----------------------------------------------------------------*/
2035 isBitwiseOptimizable (iCode * ic)
2037 sym_link *ltype = getSpec (operandType (IC_LEFT (ic)));
2038 sym_link *rtype = getSpec (operandType (IC_RIGHT (ic)));
2040 /* bitwise operations are considered optimizable
2041 under the following conditions (Jean-Louis VERN)
2053 if (IS_LITERAL(rtype) ||
2054 (IS_BITVAR (ltype) && IN_BITSPACE (SPEC_OCLS (ltype))))
2060 /*-----------------------------------------------------------------*/
2061 /* packRegsForAccUse - pack registers for acc use */
2062 /*-----------------------------------------------------------------*/
2064 packRegsForAccUse (iCode * ic)
2068 /* if this is an aggregate, e.g. a one byte char array */
2069 if (IS_AGGREGATE(operandType(IC_RESULT(ic)))) {
2073 /* if + or - then it has to be one byte result */
2074 if ((ic->op == '+' || ic->op == '-')
2075 && getSize (operandType (IC_RESULT (ic))) > 1)
2078 /* if shift operation make sure right side is not a literal */
2079 if (ic->op == RIGHT_OP &&
2080 (isOperandLiteral (IC_RIGHT (ic)) ||
2081 getSize (operandType (IC_RESULT (ic))) > 1))
2084 if (ic->op == LEFT_OP &&
2085 (isOperandLiteral (IC_RIGHT (ic)) ||
2086 getSize (operandType (IC_RESULT (ic))) > 1))
2089 if (IS_BITWISE_OP (ic) &&
2090 getSize (operandType (IC_RESULT (ic))) > 1)
2094 /* has only one definition */
2095 if (bitVectnBitsOn (OP_DEFS (IC_RESULT (ic))) > 1)
2098 /* has only one use */
2099 if (bitVectnBitsOn (OP_USES (IC_RESULT (ic))) > 1)
2102 /* and the usage immediately follows this iCode */
2103 if (!(uic = hTabItemWithKey (iCodehTab,
2104 bitVectFirstBit (OP_USES (IC_RESULT (ic))))))
2107 if (ic->next != uic)
2110 /* if it is a conditional branch then we definitely can */
2114 if (uic->op == JUMPTABLE)
2117 /* if the usage is not is an assignment
2118 or an arithmetic / bitwise / shift operation then not */
2119 if (POINTER_SET (uic) &&
2120 getSize (aggrToPtr (operandType (IC_RESULT (uic)), FALSE)) > 1)
2123 if (uic->op != '=' &&
2124 !IS_ARITHMETIC_OP (uic) &&
2125 !IS_BITWISE_OP (uic) &&
2126 uic->op != LEFT_OP &&
2127 uic->op != RIGHT_OP)
2130 /* if used in ^ operation then make sure right is not a
2132 if (uic->op == '^' && isOperandLiteral (IC_RIGHT (uic)))
2135 /* if shift operation make sure right side is not a literal */
2136 if (uic->op == RIGHT_OP &&
2137 (isOperandLiteral (IC_RIGHT (uic)) ||
2138 getSize (operandType (IC_RESULT (uic))) > 1))
2141 if (uic->op == LEFT_OP &&
2142 (isOperandLiteral (IC_RIGHT (uic)) ||
2143 getSize (operandType (IC_RESULT (uic))) > 1))
2146 /* make sure that the result of this icode is not on the
2147 stack, since acc is used to compute stack offset */
2148 if (IS_TRUE_SYMOP (IC_RESULT (uic)) &&
2149 OP_SYMBOL (IC_RESULT (uic))->onStack)
2152 /* if either one of them in far space then we cannot */
2153 if ((IS_TRUE_SYMOP (IC_LEFT (uic)) &&
2154 isOperandInFarSpace (IC_LEFT (uic))) ||
2155 (IS_TRUE_SYMOP (IC_RIGHT (uic)) &&
2156 isOperandInFarSpace (IC_RIGHT (uic))))
2159 /* if the usage has only one operand then we can */
2160 if (IC_LEFT (uic) == NULL ||
2161 IC_RIGHT (uic) == NULL)
2164 /* make sure this is on the left side if not
2165 a '+' since '+' is commutative */
2166 if (ic->op != '+' &&
2167 IC_LEFT (uic)->key != IC_RESULT (ic)->key)
2171 // this is too dangerous and need further restrictions
2174 /* if one of them is a literal then we can */
2175 if ((IC_LEFT (uic) && IS_OP_LITERAL (IC_LEFT (uic))) ||
2176 (IC_RIGHT (uic) && IS_OP_LITERAL (IC_RIGHT (uic))))
2178 OP_SYMBOL (IC_RESULT (ic))->accuse = 1;
2183 /* if the other one is not on stack then we can */
2184 if (IC_LEFT (uic)->key == IC_RESULT (ic)->key &&
2185 (IS_ITEMP (IC_RIGHT (uic)) ||
2186 (IS_TRUE_SYMOP (IC_RIGHT (uic)) &&
2187 !OP_SYMBOL (IC_RIGHT (uic))->onStack)))
2190 if (IC_RIGHT (uic)->key == IC_RESULT (ic)->key &&
2191 (IS_ITEMP (IC_LEFT (uic)) ||
2192 (IS_TRUE_SYMOP (IC_LEFT (uic)) &&
2193 !OP_SYMBOL (IC_LEFT (uic))->onStack)))
2199 OP_SYMBOL (IC_RESULT (ic))->accuse = 1;
2204 /*-----------------------------------------------------------------*/
2205 /* packForPush - hueristics to reduce iCode for pushing */
2206 /*-----------------------------------------------------------------*/
2208 packForPush (iCode * ic, eBBlock * ebp)
2213 if (ic->op != IPUSH || !IS_ITEMP (IC_LEFT (ic)))
2216 /* must have only definition & one usage */
2217 if (bitVectnBitsOn (OP_DEFS (IC_LEFT (ic))) != 1 ||
2218 bitVectnBitsOn (OP_USES (IC_LEFT (ic))) != 1)
2221 /* find the definition */
2222 if (!(dic = hTabItemWithKey (iCodehTab,
2223 bitVectFirstBit (OP_DEFS (IC_LEFT (ic))))))
2226 if (dic->op != '=' || POINTER_SET (dic))
2229 /* make sure the right side does not have any definitions
2231 dbv = OP_DEFS(IC_RIGHT(dic));
2232 for (lic = ic; lic && lic != dic ; lic = lic->prev) {
2233 if (bitVectBitValue(dbv,lic->key))
2236 /* make sure they have the same type */
2238 sym_link *itype=operandType(IC_LEFT(ic));
2239 sym_link *ditype=operandType(IC_RIGHT(dic));
2241 if (SPEC_USIGN(itype)!=SPEC_USIGN(ditype) ||
2242 SPEC_LONG(itype)!=SPEC_LONG(ditype))
2245 /* extend the live range of replaced operand if needed */
2246 if (OP_SYMBOL(IC_RIGHT(dic))->liveTo < ic->seq) {
2247 OP_SYMBOL(IC_RIGHT(dic))->liveTo = ic->seq;
2249 /* we now we know that it has one & only one def & use
2250 and the that the definition is an assignment */
2251 IC_LEFT (ic) = IC_RIGHT (dic);
2253 remiCodeFromeBBlock (ebp, dic);
2254 hTabDeleteItem (&iCodehTab, dic->key, dic, DELETE_ITEM, NULL);
2257 /*-----------------------------------------------------------------*/
2258 /* packRegisters - does some transformations to reduce register */
2260 /*-----------------------------------------------------------------*/
2262 packRegisters (eBBlock * ebp)
2272 /* look for assignments of the form */
2273 /* iTempNN = TRueSym (someoperation) SomeOperand */
2275 /* TrueSym := iTempNN:1 */
2276 for (ic = ebp->sch; ic; ic = ic->next)
2278 /* find assignment of the form TrueSym := iTempNN:1 */
2279 if (ic->op == '=' && !POINTER_SET (ic))
2280 change += packRegsForAssign (ic, ebp);
2287 for (ic = ebp->sch; ic; ic = ic->next)
2289 /* if this is an itemp & result of an address of a true sym
2290 then mark this as rematerialisable */
2291 if (ic->op == ADDRESS_OF &&
2292 IS_ITEMP (IC_RESULT (ic)) &&
2293 IS_TRUE_SYMOP (IC_LEFT (ic)) &&
2294 bitVectnBitsOn (OP_DEFS (IC_RESULT (ic))) == 1 &&
2295 !OP_SYMBOL (IC_LEFT (ic))->onStack)
2298 OP_SYMBOL (IC_RESULT (ic))->remat = 1;
2299 OP_SYMBOL (IC_RESULT (ic))->rematiCode = ic;
2300 OP_SYMBOL (IC_RESULT (ic))->usl.spillLoc = NULL;
2304 /* if straight assignment then carry remat flag if
2305 this is the only definition */
2306 if (ic->op == '=' &&
2307 !POINTER_SET (ic) &&
2308 IS_SYMOP (IC_RIGHT (ic)) &&
2309 OP_SYMBOL (IC_RIGHT (ic))->remat &&
2310 !IS_CAST_ICODE(OP_SYMBOL (IC_RIGHT (ic))->rematiCode) &&
2311 bitVectnBitsOn (OP_SYMBOL (IC_RESULT (ic))->defs) <= 1)
2314 OP_SYMBOL (IC_RESULT (ic))->remat =
2315 OP_SYMBOL (IC_RIGHT (ic))->remat;
2316 OP_SYMBOL (IC_RESULT (ic))->rematiCode =
2317 OP_SYMBOL (IC_RIGHT (ic))->rematiCode;
2320 /* if cast to a generic pointer & the pointer being
2321 cast is remat, then we can remat this cast as well */
2322 if (ic->op == CAST &&
2323 IS_SYMOP(IC_RIGHT(ic)) &&
2324 OP_SYMBOL(IC_RIGHT(ic))->remat ) {
2325 sym_link *to_type = operandType(IC_LEFT(ic));
2326 sym_link *from_type = operandType(IC_RIGHT(ic));
2327 if (IS_GENPTR(to_type) && IS_PTR(from_type)) {
2328 OP_SYMBOL (IC_RESULT (ic))->remat = 1;
2329 OP_SYMBOL (IC_RESULT (ic))->rematiCode = ic;
2330 OP_SYMBOL (IC_RESULT (ic))->usl.spillLoc = NULL;
2334 /* if this is a +/- operation with a rematerizable
2335 then mark this as rematerializable as well */
2336 if ((ic->op == '+' || ic->op == '-') &&
2337 (IS_SYMOP (IC_LEFT (ic)) &&
2338 IS_ITEMP (IC_RESULT (ic)) &&
2339 IS_OP_LITERAL (IC_RIGHT (ic))) &&
2340 OP_SYMBOL (IC_LEFT (ic))->remat &&
2341 (!IS_SYMOP (IC_RIGHT (ic)) || !IS_CAST_ICODE(OP_SYMBOL (IC_RIGHT (ic))->rematiCode)) &&
2342 bitVectnBitsOn (OP_DEFS (IC_RESULT (ic))) == 1)
2344 OP_SYMBOL (IC_RESULT (ic))->remat = 1;
2345 OP_SYMBOL (IC_RESULT (ic))->rematiCode = ic;
2346 OP_SYMBOL (IC_RESULT (ic))->usl.spillLoc = NULL;
2349 /* mark the pointer usages */
2350 if (POINTER_SET (ic))
2351 OP_SYMBOL (IC_RESULT (ic))->uptr = 1;
2353 if (POINTER_GET (ic))
2354 OP_SYMBOL (IC_LEFT (ic))->uptr = 1;
2358 /* if we are using a symbol on the stack
2359 then we should say mcs51_ptrRegReq */
2360 if (ic->op == IFX && IS_SYMOP (IC_COND (ic)))
2361 mcs51_ptrRegReq += ((OP_SYMBOL (IC_COND (ic))->onStack ||
2362 OP_SYMBOL (IC_COND (ic))->iaccess) ? 1 : 0);
2363 else if (ic->op == JUMPTABLE && IS_SYMOP (IC_JTCOND (ic)))
2364 mcs51_ptrRegReq += ((OP_SYMBOL (IC_JTCOND (ic))->onStack ||
2365 OP_SYMBOL (IC_JTCOND (ic))->iaccess) ? 1 : 0);
2368 if (IS_SYMOP (IC_LEFT (ic)))
2369 mcs51_ptrRegReq += ((OP_SYMBOL (IC_LEFT (ic))->onStack ||
2370 OP_SYMBOL (IC_LEFT (ic))->iaccess) ? 1 : 0);
2371 if (IS_SYMOP (IC_RIGHT (ic)))
2372 mcs51_ptrRegReq += ((OP_SYMBOL (IC_RIGHT (ic))->onStack ||
2373 OP_SYMBOL (IC_RIGHT (ic))->iaccess) ? 1 : 0);
2374 if (IS_SYMOP (IC_RESULT (ic)))
2375 mcs51_ptrRegReq += ((OP_SYMBOL (IC_RESULT (ic))->onStack ||
2376 OP_SYMBOL (IC_RESULT (ic))->iaccess) ? 1 : 0);
2380 /* if the condition of an if instruction
2381 is defined in the previous instruction and
2382 this is the only usage then
2383 mark the itemp as a conditional */
2384 if ((IS_CONDITIONAL (ic) ||
2385 (IS_BITWISE_OP(ic) && isBitwiseOptimizable (ic))) &&
2386 ic->next && ic->next->op == IFX &&
2387 bitVectnBitsOn (OP_USES(IC_RESULT(ic)))==1 &&
2388 isOperandEqual (IC_RESULT (ic), IC_COND (ic->next)) &&
2389 OP_SYMBOL (IC_RESULT (ic))->liveTo <= ic->next->seq)
2391 OP_SYMBOL (IC_RESULT (ic))->regType = REG_CND;
2395 /* reduce for support function calls */
2396 if (ic->supportRtn || ic->op == '+' || ic->op == '-')
2397 packRegsForSupport (ic, ebp);
2399 /* some cases the redundant moves can
2400 can be eliminated for return statements */
2401 if ((ic->op == RETURN || ic->op == SEND) &&
2402 !isOperandInFarSpace (IC_LEFT (ic)) &&
2403 options.model == MODEL_SMALL) {
2404 if (0 && options.stackAuto) {
2405 /* we should check here if acc will be clobbered for stack
2406 offset calculations */
2408 packRegsForOneuse (ic, IC_LEFT (ic), ebp);
2412 /* if pointer set & left has a size more than
2413 one and right is not in far space */
2414 if (POINTER_SET (ic) &&
2415 !isOperandInFarSpace (IC_RIGHT (ic)) &&
2416 !OP_SYMBOL (IC_RESULT (ic))->remat &&
2417 !IS_OP_RUONLY (IC_RIGHT (ic)) &&
2418 getSize (aggrToPtr (operandType (IC_RESULT (ic)), FALSE)) > 1)
2420 packRegsForOneuse (ic, IC_RESULT (ic), ebp);
2422 /* if pointer get */
2423 if (POINTER_GET (ic) &&
2424 !isOperandInFarSpace (IC_RESULT (ic)) &&
2425 !OP_SYMBOL (IC_LEFT (ic))->remat &&
2426 !IS_OP_RUONLY (IC_RESULT (ic)) &&
2427 getSize (aggrToPtr (operandType (IC_LEFT (ic)), FALSE)) > 1)
2429 packRegsForOneuse (ic, IC_LEFT (ic), ebp);
2432 /* if this is cast for intergral promotion then
2433 check if only use of the definition of the
2434 operand being casted/ if yes then replace
2435 the result of that arithmetic operation with
2436 this result and get rid of the cast */
2439 sym_link *fromType = operandType (IC_RIGHT (ic));
2440 sym_link *toType = operandType (IC_LEFT (ic));
2442 if (IS_INTEGRAL (fromType) && IS_INTEGRAL (toType) &&
2443 getSize (fromType) != getSize (toType) &&
2444 SPEC_USIGN (fromType) == SPEC_USIGN (toType))
2447 iCode *dic = packRegsForOneuse (ic, IC_RIGHT (ic), ebp);
2450 if (IS_ARITHMETIC_OP (dic))
2452 IC_RESULT (dic) = IC_RESULT (ic);
2453 remiCodeFromeBBlock (ebp, ic);
2454 hTabDeleteItem (&iCodehTab, ic->key, ic, DELETE_ITEM, NULL);
2455 OP_DEFS (IC_RESULT (dic)) = bitVectSetBit (OP_DEFS (IC_RESULT (dic)), dic->key);
2459 OP_SYMBOL (IC_RIGHT (ic))->ruonly = 0;
2465 /* if the type from and type to are the same
2466 then if this is the only use then packit */
2467 if (compareType (operandType (IC_RIGHT (ic)),
2468 operandType (IC_LEFT (ic))) == 1)
2470 iCode *dic = packRegsForOneuse (ic, IC_RIGHT (ic), ebp);
2473 IC_RESULT (dic) = IC_RESULT (ic);
2474 remiCodeFromeBBlock (ebp, ic);
2475 hTabDeleteItem (&iCodehTab, ic->key, ic, DELETE_ITEM, NULL);
2476 OP_DEFS (IC_RESULT (dic)) = bitVectSetBit (OP_DEFS (IC_RESULT (dic)), dic->key);
2484 iTempNN := (some variable in farspace) V1
2489 if (ic->op == IPUSH)
2491 packForPush (ic, ebp);
2495 /* pack registers for accumulator use, when the
2496 result of an arithmetic or bit wise operation
2497 has only one use, that use is immediately following
2498 the defintion and the using iCode has only one
2499 operand or has two operands but one is literal &
2500 the result of that operation is not on stack then
2501 we can leave the result of this operation in acc:b
2503 if ((IS_ARITHMETIC_OP (ic)
2504 || IS_CONDITIONAL(ic)
2505 || IS_BITWISE_OP (ic)
2506 || ic->op == LEFT_OP || ic->op == RIGHT_OP || ic->op == CALL
2507 || (ic->op == ADDRESS_OF && isOperandOnStack (IC_LEFT (ic)))
2509 IS_ITEMP (IC_RESULT (ic)) &&
2510 getSize (operandType (IC_RESULT (ic))) <= 2)
2512 packRegsForAccUse (ic);
2516 /*-----------------------------------------------------------------*/
2517 /* assignRegisters - assigns registers to each live range as need */
2518 /*-----------------------------------------------------------------*/
2520 mcs51_assignRegisters (eBBlock ** ebbs, int count)
2525 setToNull ((void *) &_G.funcrUsed);
2526 mcs51_ptrRegReq = _G.stackExtend = _G.dataExtend = 0;
2529 /* change assignments this will remove some
2530 live ranges reducing some register pressure */
2531 for (i = 0; i < count; i++)
2532 packRegisters (ebbs[i]);
2534 if (options.dump_pack)
2535 dumpEbbsToFileExt (DUMP_PACK, ebbs, count);
2537 /* first determine for each live range the number of
2538 registers & the type of registers required for each */
2541 /* and serially allocate registers */
2542 serialRegAssign (ebbs, count);
2544 /* if stack was extended then tell the user */
2547 /* werror(W_TOOMANY_SPILS,"stack", */
2548 /* _G.stackExtend,currFunc->name,""); */
2554 /* werror(W_TOOMANY_SPILS,"data space", */
2555 /* _G.dataExtend,currFunc->name,""); */
2559 /* after that create the register mask
2560 for each of the instruction */
2561 createRegMask (ebbs, count);
2563 /* redo that offsets for stacked automatic variables */
2564 redoStackOffsets ();
2566 if (options.dump_rassgn)
2568 dumpEbbsToFileExt (DUMP_RASSGN, ebbs, count);
2569 dumpLiveRanges (DUMP_LRANGE, liveRanges);
2572 /* do the overlaysegment stuff SDCCmem.c */
2573 doOverlays (ebbs, count);
2575 /* now get back the chain */
2576 ic = iCodeLabelOptimize (iCodeFromeBBlock (ebbs, count));
2580 /* free up any _G.stackSpil locations allocated */
2581 applyToSet (_G.stackSpil, deallocStackSpil);
2583 setToNull ((void **) &_G.stackSpil);
2584 setToNull ((void **) &_G.spiltSet);
2585 /* mark all registers as free */