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 *);
48 bitVect *totRegAssigned; /* final set of LRs that got into registers */
51 bitVect *funcrUsed; /* registers used in a function */
57 /* Shared with gen.c */
58 int mcs51_ptrRegReq; /* one byte pointer register required */
64 {REG_GPR, R2_IDX, REG_GPR, "r2", "ar2", "0", 2, 1},
65 {REG_GPR, R3_IDX, REG_GPR, "r3", "ar3", "0", 3, 1},
66 {REG_GPR, R4_IDX, REG_GPR, "r4", "ar4", "0", 4, 1},
67 {REG_GPR, R5_IDX, REG_GPR, "r5", "ar5", "0", 5, 1},
68 {REG_GPR, R6_IDX, REG_GPR, "r6", "ar6", "0", 6, 1},
69 {REG_GPR, R7_IDX, REG_GPR, "r7", "ar7", "0", 7, 1},
70 {REG_PTR, R0_IDX, REG_PTR, "r0", "ar0", "0", 0, 1},
71 {REG_PTR, R1_IDX, REG_PTR, "r1", "ar1", "0", 1, 1},
72 {REG_GPR, X8_IDX, REG_GPR, "x8", "x8", "xreg", 0, 1},
73 {REG_GPR, X9_IDX, REG_GPR, "x9", "x9", "xreg", 1, 1},
74 {REG_GPR, X10_IDX, REG_GPR, "x10", "x10", "xreg", 2, 1},
75 {REG_GPR, X11_IDX, REG_GPR, "x11", "x11", "xreg", 3, 1},
76 {REG_GPR, X12_IDX, REG_GPR, "x12", "x12", "xreg", 4, 1},
77 {REG_CND, CND_IDX, REG_CND, "C", "C", "xreg", 0, 1},
80 static void spillThis (symbol *);
81 static void freeAllRegs ();
83 /*-----------------------------------------------------------------*/
84 /* allocReg - allocates register of given type */
85 /*-----------------------------------------------------------------*/
91 for (i = 0; i < mcs51_nRegs; i++)
94 /* if type is given as 0 then any
95 free register will do */
99 regs8051[i].isFree = 0;
102 bitVectSetBit (currFunc->regsUsed, i);
105 /* other wise look for specific type
107 if (regs8051[i].isFree &&
108 regs8051[i].type == type)
110 regs8051[i].isFree = 0;
113 bitVectSetBit (currFunc->regsUsed, i);
120 /*-----------------------------------------------------------------*/
121 /* mcs51_regWithIdx - returns pointer to register wit index number */
122 /*-----------------------------------------------------------------*/
124 mcs51_regWithIdx (int idx)
128 for (i = 0; i < mcs51_nRegs; i++)
129 if (regs8051[i].rIdx == idx)
132 werror (E_INTERNAL_ERROR, __FILE__, __LINE__,
133 "regWithIdx not found");
137 /*-----------------------------------------------------------------*/
138 /* freeReg - frees a register */
139 /*-----------------------------------------------------------------*/
145 werror (E_INTERNAL_ERROR, __FILE__, __LINE__,
146 "freeReg - Freeing NULL register");
154 /*-----------------------------------------------------------------*/
155 /* nFreeRegs - returns number of free registers */
156 /*-----------------------------------------------------------------*/
163 for (i = 0; i < mcs51_nRegs; i++)
164 if (regs8051[i].isFree && regs8051[i].type == type)
169 /*-----------------------------------------------------------------*/
170 /* nfreeRegsType - free registers with type */
171 /*-----------------------------------------------------------------*/
173 nfreeRegsType (int type)
178 if ((nfr = nFreeRegs (type)) == 0)
179 return nFreeRegs (REG_GPR);
182 return nFreeRegs (type);
185 /*-----------------------------------------------------------------*/
186 /* useReg - marks a register as used */
187 /*-----------------------------------------------------------------*/
194 /*-----------------------------------------------------------------*/
195 /* computeSpillable - given a point find the spillable live ranges */
196 /*-----------------------------------------------------------------*/
198 computeSpillable (iCode * ic)
202 /* spillable live ranges are those that are live at this
203 point . the following categories need to be subtracted
205 a) - those that are already spilt
206 b) - if being used by this one
207 c) - defined by this one */
209 spillable = bitVectCopy (ic->rlive);
211 bitVectCplAnd (spillable, _G.spiltSet); /* those already spilt */
213 bitVectCplAnd (spillable, ic->uses); /* used in this one */
214 bitVectUnSetBit (spillable, ic->defKey);
215 spillable = bitVectIntersect (spillable, _G.regAssigned);
220 /*-----------------------------------------------------------------*/
221 /* noSpilLoc - return true if a variable has no spil location */
222 /*-----------------------------------------------------------------*/
224 noSpilLoc (symbol * sym, eBBlock * ebp, iCode * ic)
226 return (sym->usl.spillLoc ? 0 : 1);
229 /*-----------------------------------------------------------------*/
230 /* hasSpilLoc - will return 1 if the symbol has spil location */
231 /*-----------------------------------------------------------------*/
233 hasSpilLoc (symbol * sym, eBBlock * ebp, iCode * ic)
235 return (sym->usl.spillLoc ? 1 : 0);
238 /*-----------------------------------------------------------------*/
239 /* directSpilLoc - will return 1 if the splilocation is in direct */
240 /*-----------------------------------------------------------------*/
242 directSpilLoc (symbol * sym, eBBlock * ebp, iCode * ic)
244 if (sym->usl.spillLoc &&
245 (IN_DIRSPACE (SPEC_OCLS (sym->usl.spillLoc->etype))))
251 /*-----------------------------------------------------------------*/
252 /* hasSpilLocnoUptr - will return 1 if the symbol has spil location */
253 /* but is not used as a pointer */
254 /*-----------------------------------------------------------------*/
256 hasSpilLocnoUptr (symbol * sym, eBBlock * ebp, iCode * ic)
258 return ((sym->usl.spillLoc && !sym->uptr) ? 1 : 0);
261 /*-----------------------------------------------------------------*/
262 /* rematable - will return 1 if the remat flag is set */
263 /*-----------------------------------------------------------------*/
265 rematable (symbol * sym, eBBlock * ebp, iCode * ic)
270 /*-----------------------------------------------------------------*/
271 /* notUsedInRemaining - not used or defined in remain of the block */
272 /*-----------------------------------------------------------------*/
274 notUsedInRemaining (symbol * sym, eBBlock * ebp, iCode * ic)
276 return ((usedInRemaining (operandFromSymbol (sym), ic) ? 0 : 1) &&
277 allDefsOutOfRange (sym->defs, ebp->fSeq, ebp->lSeq));
280 /*-----------------------------------------------------------------*/
281 /* allLRs - return true for all */
282 /*-----------------------------------------------------------------*/
284 allLRs (symbol * sym, eBBlock * ebp, iCode * ic)
289 /*-----------------------------------------------------------------*/
290 /* liveRangesWith - applies function to a given set of live range */
291 /*-----------------------------------------------------------------*/
293 liveRangesWith (bitVect * lrs, int (func) (symbol *, eBBlock *, iCode *),
294 eBBlock * ebp, iCode * ic)
299 if (!lrs || !lrs->size)
302 for (i = 1; i < lrs->size; i++)
305 if (!bitVectBitValue (lrs, i))
308 /* if we don't find it in the live range
309 hash table we are in serious trouble */
310 if (!(sym = hTabItemWithKey (liveRanges, i)))
312 werror (E_INTERNAL_ERROR, __FILE__, __LINE__,
313 "liveRangesWith could not find liveRange");
317 if (func (sym, ebp, ic) && bitVectBitValue (_G.regAssigned, sym->key))
318 addSetHead (&rset, sym);
325 /*-----------------------------------------------------------------*/
326 /* leastUsedLR - given a set determines which is the least used */
327 /*-----------------------------------------------------------------*/
329 leastUsedLR (set * sset)
331 symbol *sym = NULL, *lsym = NULL;
333 sym = lsym = setFirstItem (sset);
338 for (; lsym; lsym = setNextItem (sset))
341 /* if usage is the same then prefer
342 the spill the smaller of the two */
343 if (lsym->used == sym->used)
344 if (getSize (lsym->type) < getSize (sym->type))
348 if (lsym->used < sym->used)
353 setToNull ((void **) &sset);
358 /*-----------------------------------------------------------------*/
359 /* noOverLap - will iterate through the list looking for over lap */
360 /*-----------------------------------------------------------------*/
362 noOverLap (set * itmpStack, symbol * fsym)
367 for (sym = setFirstItem (itmpStack); sym;
368 sym = setNextItem (itmpStack))
370 if (bitVectBitValue(sym->clashes,fsym->key)) return 0;
376 /*-----------------------------------------------------------------*/
377 /* isFree - will return 1 if the a free spil location is found */
378 /*-----------------------------------------------------------------*/
383 V_ARG (symbol **, sloc);
384 V_ARG (symbol *, fsym);
386 /* if already found */
390 /* if it is free && and the itmp assigned to
391 this does not have any overlapping live ranges
392 with the one currently being assigned and
393 the size can be accomodated */
395 noOverLap (sym->usl.itmpStack, fsym) &&
396 getSize (sym->type) >= getSize (fsym->type))
405 /*-----------------------------------------------------------------*/
406 /* spillLRWithPtrReg :- will spil those live ranges which use PTR */
407 /*-----------------------------------------------------------------*/
409 spillLRWithPtrReg (symbol * forSym)
415 if (!_G.regAssigned ||
416 bitVectIsZero (_G.regAssigned))
419 r0 = mcs51_regWithIdx (R0_IDX);
420 r1 = mcs51_regWithIdx (R1_IDX);
422 /* for all live ranges */
423 for (lrsym = hTabFirstItem (liveRanges, &k); lrsym;
424 lrsym = hTabNextItem (liveRanges, &k))
428 /* if no registers assigned to it or spilt */
429 /* if it does not overlap with this then
430 not need to spill it */
432 if (lrsym->isspilt || !lrsym->nRegs ||
433 (lrsym->liveTo < forSym->liveFrom))
436 /* go thru the registers : if it is either
437 r0 or r1 then spil it */
438 for (j = 0; j < lrsym->nRegs; j++)
439 if (lrsym->regs[j] == r0 ||
440 lrsym->regs[j] == r1)
449 /*-----------------------------------------------------------------*/
450 /* createStackSpil - create a location on the stack to spil */
451 /*-----------------------------------------------------------------*/
453 createStackSpil (symbol * sym)
456 int useXstack, model;
460 /* first go try and find a free one that is already
461 existing on the stack */
462 if (applyToSet (_G.stackSpil, isFree, &sloc, sym))
464 /* found a free one : just update & return */
465 sym->usl.spillLoc = sloc;
468 addSetHead (&sloc->usl.itmpStack, sym);
472 /* could not then have to create one , this is the hard part
473 we need to allocate this on the stack : this is really a
474 hack!! but cannot think of anything better at this time */
476 if (sprintf (slocBuffer, "sloc%d", _G.slocNum++) >= sizeof (slocBuffer))
478 fprintf (stderr, "***Internal error: slocBuffer overflowed: %s:%d\n",
483 sloc = newiTemp (slocBuffer);
485 /* set the type to the spilling symbol */
486 sloc->type = copyLinkChain (sym->type);
487 sloc->etype = getSpec (sloc->type);
488 SPEC_SCLS (sloc->etype) = S_DATA;
489 SPEC_EXTR (sloc->etype) = 0;
490 SPEC_STAT (sloc->etype) = 0;
491 SPEC_VOLATILE(sloc->etype) = 0;
492 SPEC_ABSA(sloc->etype) = 0;
494 /* we don't allow it to be allocated`
495 onto the external stack since : so we
496 temporarily turn it off ; we also
497 turn off memory model to prevent
498 the spil from going to the external storage
501 useXstack = options.useXstack;
502 model = options.model;
503 /* noOverlay = options.noOverlay; */
504 /* options.noOverlay = 1; */
505 options.model = options.useXstack = 0;
509 options.useXstack = useXstack;
510 options.model = model;
511 /* options.noOverlay = noOverlay; */
512 sloc->isref = 1; /* to prevent compiler warning */
514 /* if it is on the stack then update the stack */
515 if (IN_STACK (sloc->etype))
517 currFunc->stack += getSize (sloc->type);
518 _G.stackExtend += getSize (sloc->type);
521 _G.dataExtend += getSize (sloc->type);
523 /* add it to the _G.stackSpil set */
524 addSetHead (&_G.stackSpil, sloc);
525 sym->usl.spillLoc = sloc;
528 /* add it to the set of itempStack set
529 of the spill location */
530 addSetHead (&sloc->usl.itmpStack, sym);
534 /*-----------------------------------------------------------------*/
535 /* isSpiltOnStack - returns true if the spil location is on stack */
536 /*-----------------------------------------------------------------*/
538 isSpiltOnStack (symbol * sym)
548 /* if (sym->_G.stackSpil) */
551 if (!sym->usl.spillLoc)
554 etype = getSpec (sym->usl.spillLoc->type);
555 if (IN_STACK (etype))
561 /*-----------------------------------------------------------------*/
562 /* spillThis - spils a specific operand */
563 /*-----------------------------------------------------------------*/
565 spillThis (symbol * sym)
568 /* if this is rematerializable or has a spillLocation
569 we are okay, else we need to create a spillLocation
571 if (!(sym->remat || sym->usl.spillLoc))
572 createStackSpil (sym);
575 /* mark it has spilt & put it in the spilt set */
576 sym->isspilt = sym->spillA = 1;
577 _G.spiltSet = bitVectSetBit (_G.spiltSet, sym->key);
579 bitVectUnSetBit (_G.regAssigned, sym->key);
580 bitVectUnSetBit (_G.totRegAssigned, sym->key);
582 for (i = 0; i < sym->nRegs; i++)
586 freeReg (sym->regs[i]);
590 /* if spilt on stack then free up r0 & r1
591 if they could have been assigned to some
593 if (!mcs51_ptrRegReq && isSpiltOnStack (sym))
596 spillLRWithPtrReg (sym);
599 if (sym->usl.spillLoc && !sym->remat)
600 sym->usl.spillLoc->allocreq++;
604 /*-----------------------------------------------------------------*/
605 /* selectSpil - select a iTemp to spil : rather a simple procedure */
606 /*-----------------------------------------------------------------*/
608 selectSpil (iCode * ic, eBBlock * ebp, symbol * forSym)
610 bitVect *lrcs = NULL;
614 /* get the spillable live ranges */
615 lrcs = computeSpillable (ic);
617 /* get all live ranges that are rematerizable */
618 if ((selectS = liveRangesWith (lrcs, rematable, ebp, ic)))
621 /* return the least used of these */
622 return leastUsedLR (selectS);
625 /* get live ranges with spillLocations in direct space */
626 if ((selectS = liveRangesWith (lrcs, directSpilLoc, ebp, ic)))
628 sym = leastUsedLR (selectS);
629 strcpy (sym->rname, (sym->usl.spillLoc->rname[0] ?
630 sym->usl.spillLoc->rname :
631 sym->usl.spillLoc->name));
633 /* mark it as allocation required */
634 sym->usl.spillLoc->allocreq++;
638 /* if the symbol is local to the block then */
639 if (forSym->liveTo < ebp->lSeq)
642 /* check if there are any live ranges allocated
643 to registers that are not used in this block */
644 if (!_G.blockSpil && (selectS = liveRangesWith (lrcs, notUsedInBlock, ebp, ic)))
646 sym = leastUsedLR (selectS);
647 /* if this is not rematerializable */
656 /* check if there are any live ranges that not
657 used in the remainder of the block */
658 if (!_G.blockSpil && (selectS = liveRangesWith (lrcs, notUsedInRemaining, ebp, ic)))
660 sym = leastUsedLR (selectS);
673 /* find live ranges with spillocation && not used as pointers */
674 if ((selectS = liveRangesWith (lrcs, hasSpilLocnoUptr, ebp, ic)))
677 sym = leastUsedLR (selectS);
678 /* mark this as allocation required */
679 sym->usl.spillLoc->allocreq++;
683 /* find live ranges with spillocation */
684 if ((selectS = liveRangesWith (lrcs, hasSpilLoc, ebp, ic)))
687 sym = leastUsedLR (selectS);
688 sym->usl.spillLoc->allocreq++;
692 /* couldn't find then we need to create a spil
693 location on the stack , for which one? the least
695 if ((selectS = liveRangesWith (lrcs, noSpilLoc, ebp, ic)))
698 /* return a created spil location */
699 sym = createStackSpil (leastUsedLR (selectS));
700 sym->usl.spillLoc->allocreq++;
704 /* this is an extreme situation we will spill
705 this one : happens very rarely but it does happen */
711 /*-----------------------------------------------------------------*/
712 /* spilSomething - spil some variable & mark registers as free */
713 /*-----------------------------------------------------------------*/
715 spilSomething (iCode * ic, eBBlock * ebp, symbol * forSym)
720 /* get something we can spil */
721 ssym = selectSpil (ic, ebp, forSym);
723 /* mark it as spilt */
724 ssym->isspilt = ssym->spillA = 1;
725 _G.spiltSet = bitVectSetBit (_G.spiltSet, ssym->key);
727 /* mark it as not register assigned &
728 take it away from the set */
729 bitVectUnSetBit (_G.regAssigned, ssym->key);
730 bitVectUnSetBit (_G.totRegAssigned, ssym->key);
732 /* mark the registers as free */
733 for (i = 0; i < ssym->nRegs; i++)
735 freeReg (ssym->regs[i]);
737 /* if spilt on stack then free up r0 & r1
738 if they could have been assigned to as gprs */
739 if (!mcs51_ptrRegReq && isSpiltOnStack (ssym))
742 spillLRWithPtrReg (ssym);
745 /* if this was a block level spil then insert push & pop
746 at the start & end of block respectively */
749 iCode *nic = newiCode (IPUSH, operandFromSymbol (ssym), NULL);
750 /* add push to the start of the block */
751 addiCodeToeBBlock (ebp, nic, (ebp->sch->op == LABEL ?
752 ebp->sch->next : ebp->sch));
753 nic = newiCode (IPOP, operandFromSymbol (ssym), NULL);
754 /* add pop to the end of the block */
755 addiCodeToeBBlock (ebp, nic, NULL);
758 /* if spilt because not used in the remainder of the
759 block then add a push before this instruction and
760 a pop at the end of the block */
761 if (ssym->remainSpil)
764 iCode *nic = newiCode (IPUSH, operandFromSymbol (ssym), NULL);
765 /* add push just before this instruction */
766 addiCodeToeBBlock (ebp, nic, ic);
768 nic = newiCode (IPOP, operandFromSymbol (ssym), NULL);
769 /* add pop to the end of the block */
770 addiCodeToeBBlock (ebp, nic, NULL);
779 /*-----------------------------------------------------------------*/
780 /* getRegPtr - will try for PTR if not a GPR type if not spil */
781 /*-----------------------------------------------------------------*/
783 getRegPtr (iCode * ic, eBBlock * ebp, symbol * sym)
788 /* try for a ptr type */
789 if ((reg = allocReg (REG_PTR)))
792 /* try for gpr type */
793 if ((reg = allocReg (REG_GPR)))
796 /* we have to spil */
797 if (!spilSomething (ic, ebp, sym))
800 /* this looks like an infinite loop but
801 in really selectSpil will abort */
805 /*-----------------------------------------------------------------*/
806 /* getRegGpr - will try for GPR if not spil */
807 /*-----------------------------------------------------------------*/
809 getRegGpr (iCode * ic, eBBlock * ebp, symbol * sym)
814 /* try for gpr type */
815 if ((reg = allocReg (REG_GPR)))
818 if (!mcs51_ptrRegReq)
819 if ((reg = allocReg (REG_PTR)))
822 /* we have to spil */
823 if (!spilSomething (ic, ebp, sym))
826 /* this looks like an infinite loop but
827 in really selectSpil will abort */
831 /*-----------------------------------------------------------------*/
832 /* getRegPtrNoSpil - get it cannot split */
833 /*-----------------------------------------------------------------*/
834 static regs *getRegPtrNoSpil()
838 /* try for a ptr type */
839 if ((reg = allocReg (REG_PTR)))
842 /* try for gpr type */
843 if ((reg = allocReg (REG_GPR)))
849 /*-----------------------------------------------------------------*/
850 /* getRegGprNoSpil - get it cannot split */
851 /*-----------------------------------------------------------------*/
852 static regs *getRegGprNoSpil()
856 if ((reg = allocReg (REG_GPR)))
859 if (!mcs51_ptrRegReq)
860 if ((reg = allocReg (REG_PTR)))
866 /*-----------------------------------------------------------------*/
867 /* symHasReg - symbol has a given register */
868 /*-----------------------------------------------------------------*/
870 symHasReg (symbol * sym, regs * reg)
874 for (i = 0; i < sym->nRegs; i++)
875 if (sym->regs[i] == reg)
881 /*-----------------------------------------------------------------*/
882 /* deassignLRs - check the live to and if they have registers & are */
883 /* not spilt then free up the registers */
884 /*-----------------------------------------------------------------*/
886 deassignLRs (iCode * ic, eBBlock * ebp)
892 for (sym = hTabFirstItem (liveRanges, &k); sym;
893 sym = hTabNextItem (liveRanges, &k))
897 /* if it does not end here */
898 if (sym->liveTo > ic->seq)
901 /* if it was spilt on stack then we can
902 mark the stack spil location as free */
907 sym->usl.spillLoc->isFree = 1;
913 if (!bitVectBitValue (_G.regAssigned, sym->key))
916 /* special case check if this is an IFX &
917 the privious one was a pop and the
918 previous one was not spilt then keep track
920 if (ic->op == IFX && ic->prev &&
921 ic->prev->op == IPOP &&
922 !ic->prev->parmPush &&
923 !OP_SYMBOL (IC_LEFT (ic->prev))->isspilt)
924 psym = OP_SYMBOL (IC_LEFT (ic->prev));
930 bitVectUnSetBit (_G.regAssigned, sym->key);
932 /* if the result of this one needs registers
933 and does not have it then assign it right
935 if (IC_RESULT (ic) &&
936 !(SKIP_IC2 (ic) || /* not a special icode */
937 ic->op == JUMPTABLE ||
943 (result = OP_SYMBOL (IC_RESULT (ic))) && /* has a result */
944 result->liveTo > ic->seq && /* and will live beyond this */
945 result->liveTo <= ebp->lSeq && /* does not go beyond this block */
946 result->regType == sym->regType && /* same register types */
947 result->nRegs && /* which needs registers */
948 !result->isspilt && /* and does not already have them */
950 !bitVectBitValue (_G.regAssigned, result->key) &&
951 /* the number of free regs + number of regs in this LR
952 can accomodate the what result Needs */
953 ((nfreeRegsType (result->regType) +
954 sym->nRegs) >= result->nRegs)
958 for (i = 0; i < result->nRegs; i++)
960 result->regs[i] = sym->regs[i];
962 result->regs[i] = getRegGpr (ic, ebp, result);
964 _G.regAssigned = bitVectSetBit (_G.regAssigned, result->key);
965 _G.totRegAssigned = bitVectSetBit (_G.totRegAssigned, result->key);
969 /* free the remaining */
970 for (; i < sym->nRegs; i++)
974 if (!symHasReg (psym, sym->regs[i]))
975 freeReg (sym->regs[i]);
978 freeReg (sym->regs[i]);
985 /*-----------------------------------------------------------------*/
986 /* reassignLR - reassign this to registers */
987 /*-----------------------------------------------------------------*/
989 reassignLR (operand * op)
991 symbol *sym = OP_SYMBOL (op);
994 /* not spilt any more */
995 sym->isspilt = sym->spillA = sym->blockSpil = sym->remainSpil = 0;
996 bitVectUnSetBit (_G.spiltSet, sym->key);
998 _G.regAssigned = bitVectSetBit (_G.regAssigned, sym->key);
999 _G.totRegAssigned = bitVectSetBit (_G.totRegAssigned, sym->key);
1003 for (i = 0; i < sym->nRegs; i++)
1004 sym->regs[i]->isFree = 0;
1007 /*-----------------------------------------------------------------*/
1008 /* willCauseSpill - determines if allocating will cause a spill */
1009 /*-----------------------------------------------------------------*/
1011 willCauseSpill (int nr, int rt)
1013 /* first check if there are any avlb registers
1014 of te type required */
1017 /* special case for pointer type
1018 if pointer type not avlb then
1019 check for type gpr */
1020 if (nFreeRegs (rt) >= nr)
1022 if (nFreeRegs (REG_GPR) >= nr)
1027 if (mcs51_ptrRegReq)
1029 if (nFreeRegs (rt) >= nr)
1034 if (nFreeRegs (REG_PTR) +
1035 nFreeRegs (REG_GPR) >= nr)
1040 /* it will cause a spil */
1044 /*-----------------------------------------------------------------*/
1045 /* positionRegs - the allocator can allocate same registers to res- */
1046 /* ult and operand, if this happens make sure they are in the same */
1047 /* position as the operand otherwise chaos results */
1048 /*-----------------------------------------------------------------*/
1050 positionRegs (symbol * result, symbol * opsym)
1052 int count = min (result->nRegs, opsym->nRegs);
1053 int i, j = 0, shared = 0;
1056 /* if the result has been spilt then cannot share */
1061 /* first make sure that they actually share */
1062 for (i = 0; i < count; i++)
1064 for (j = 0; j < count; j++)
1066 if (result->regs[i] == opsym->regs[j] && i != j)
1076 regs *tmp = result->regs[i];
1077 result->regs[i] = result->regs[j];
1078 result->regs[j] = tmp;
1085 /*-----------------------------------------------------------------*/
1086 /* serialRegAssign - serially allocate registers to the variables */
1087 /*-----------------------------------------------------------------*/
1089 serialRegAssign (eBBlock ** ebbs, int count)
1093 /* for all blocks */
1094 for (i = 0; i < count; i++) {
1098 if (ebbs[i]->noPath &&
1099 (ebbs[i]->entryLabel != entryLabel &&
1100 ebbs[i]->entryLabel != returnLabel))
1103 /* of all instructions do */
1104 for (ic = ebbs[i]->sch; ic; ic = ic->next) {
1106 /* if this is an ipop that means some live
1107 range will have to be assigned again */
1109 reassignLR (IC_LEFT (ic));
1111 /* if result is present && is a true symbol */
1112 if (IC_RESULT (ic) && ic->op != IFX &&
1113 IS_TRUE_SYMOP (IC_RESULT (ic)))
1114 OP_SYMBOL (IC_RESULT (ic))->allocreq++;
1116 /* take away registers from live
1117 ranges that end at this instruction */
1118 deassignLRs (ic, ebbs[i]);
1120 /* some don't need registers */
1121 if (SKIP_IC2 (ic) ||
1122 ic->op == JUMPTABLE ||
1126 (IC_RESULT (ic) && POINTER_SET (ic)))
1129 /* now we need to allocate registers
1130 only for the result */
1131 if (IC_RESULT (ic)) {
1132 symbol *sym = OP_SYMBOL (IC_RESULT (ic));
1138 /* if it does not need or is spilt
1139 or is already assigned to registers
1140 or will not live beyond this instructions */
1143 bitVectBitValue (_G.regAssigned, sym->key) ||
1144 sym->liveTo <= ic->seq)
1147 /* if some liverange has been spilt at the block level
1148 and this one live beyond this block then spil this
1150 if (_G.blockSpil && sym->liveTo > ebbs[i]->lSeq) {
1154 /* if trying to allocate this will cause
1155 a spill and there is nothing to spill
1156 or this one is rematerializable then
1158 willCS = willCauseSpill (sym->nRegs, sym->regType);
1159 spillable = computeSpillable (ic);
1160 if (sym->remat || (willCS && bitVectIsZero (spillable))) {
1165 /* if it has a spillocation & is used less than
1166 all other live ranges then spill this */
1168 if (sym->usl.spillLoc) {
1169 symbol *leastUsed = leastUsedLR (liveRangesWith (spillable,
1170 allLRs, ebbs[i], ic));
1171 if (leastUsed && leastUsed->used > sym->used) {
1176 /* if none of the liveRanges have a spillLocation then better
1177 to spill this one than anything else already assigned to registers */
1178 if (liveRangesWith(spillable,noSpilLoc,ebbs[i],ic)) {
1179 /* if this is local to this block then we might find a block spil */
1180 if (!(sym->liveFrom >= ebbs[i]->fSeq && sym->liveTo <= ebbs[i]->lSeq)) {
1187 /* if we need ptr regs for the right side
1189 if (POINTER_GET (ic) && IS_SYMOP (IC_LEFT (ic))
1190 && getSize (OP_SYMBOL (IC_LEFT (ic))->type) <= (unsigned int) PTRSIZE) {
1194 /* else we assign registers to it */
1195 _G.regAssigned = bitVectSetBit (_G.regAssigned, sym->key);
1196 _G.totRegAssigned = bitVectSetBit (_G.totRegAssigned, sym->key);
1198 for (j = 0; j < sym->nRegs; j++) {
1199 if (sym->regType == REG_PTR)
1200 sym->regs[j] = getRegPtr (ic, ebbs[i], sym);
1202 sym->regs[j] = getRegGpr (ic, ebbs[i], sym);
1204 /* if the allocation failed which means
1205 this was spilt then break */
1206 if (!sym->regs[j]) {
1211 /* if it shares registers with operands make sure
1212 that they are in the same position */
1213 if (IC_LEFT (ic) && IS_SYMOP (IC_LEFT (ic)) &&
1214 OP_SYMBOL (IC_LEFT (ic))->nRegs && ic->op != '=') {
1215 positionRegs (OP_SYMBOL (IC_RESULT (ic)),
1216 OP_SYMBOL (IC_LEFT (ic)));
1218 /* do the same for the right operand */
1219 if (IC_RIGHT (ic) && IS_SYMOP (IC_RIGHT (ic)) &&
1220 OP_SYMBOL (IC_RIGHT (ic))->nRegs) {
1221 positionRegs (OP_SYMBOL (IC_RESULT (ic)),
1222 OP_SYMBOL (IC_RIGHT (ic)));
1235 /*-----------------------------------------------------------------*/
1236 /* fillGaps - Try to fill in the Gaps left by Pass1 */
1237 /*-----------------------------------------------------------------*/
1238 static void fillGaps()
1243 if (getenv("DISABLE_FILL_GAPS")) return;
1245 /* look for livernages that was spilt by the allocator */
1246 for (sym = hTabFirstItem(liveRanges,&key) ; sym ;
1247 sym = hTabNextItem(liveRanges,&key)) {
1252 if (!sym->spillA || !sym->clashes || sym->remat) continue ;
1254 /* find the liveRanges this one clashes with, that are
1255 still assigned to registers & mark the registers as used*/
1256 for ( i = 0 ; i < sym->clashes->size ; i ++) {
1260 if (bitVectBitValue(sym->clashes,i) == 0 || /* those that clash with this */
1261 bitVectBitValue(_G.totRegAssigned,i) == 0) /* and are still assigned to registers */
1264 assert (clr = hTabItemWithKey(liveRanges,i));
1266 /* mark these registers as used */
1267 for (k = 0 ; k < clr->nRegs ; k++ )
1268 useReg(clr->regs[k]);
1271 if (willCauseSpill(sym->nRegs,sym->regType)) {
1272 /* NOPE :( clear all registers & and continue */
1277 /* THERE IS HOPE !!!! */
1278 for (i=0; i < sym->nRegs ; i++ ) {
1279 if (sym->regType == REG_PTR)
1280 sym->regs[i] = getRegPtrNoSpil ();
1282 sym->regs[i] = getRegGprNoSpil ();
1285 /* for all its definitions check if the registers
1286 allocated needs positioning NOTE: we can position
1287 only ONCE if more than One positioning required
1290 for (i = 0 ; i < sym->defs->size ; i++ ) {
1291 if (bitVectBitValue(sym->defs,i)) {
1293 if (!(ic = hTabItemWithKey(iCodehTab,i))) continue ;
1294 if (SKIP_IC(ic)) continue;
1295 assert(isSymbolEqual(sym,OP_SYMBOL(IC_RESULT(ic)))); /* just making sure */
1296 /* if left is assigned to registers */
1297 if (IS_SYMOP(IC_LEFT(ic)) &&
1298 bitVectBitValue(_G.totRegAssigned,OP_SYMBOL(IC_LEFT(ic))->key)) {
1299 pdone += positionRegs(sym,OP_SYMBOL(IC_LEFT(ic)));
1301 if (IS_SYMOP(IC_RIGHT(ic)) &&
1302 bitVectBitValue(_G.totRegAssigned,OP_SYMBOL(IC_RIGHT(ic))->key)) {
1303 pdone += positionRegs(sym,OP_SYMBOL(IC_RIGHT(ic)));
1305 if (pdone > 1) break;
1308 for (i = 0 ; i < sym->uses->size ; i++ ) {
1309 if (bitVectBitValue(sym->uses,i)) {
1311 if (!(ic = hTabItemWithKey(iCodehTab,i))) continue ;
1312 if (SKIP_IC(ic)) continue;
1313 if (!IS_ASSIGN_ICODE(ic)) continue ;
1315 /* if result is assigned to registers */
1316 if (IS_SYMOP(IC_RESULT(ic)) &&
1317 bitVectBitValue(_G.totRegAssigned,OP_SYMBOL(IC_RESULT(ic))->key)) {
1318 pdone += positionRegs(sym,OP_SYMBOL(IC_RESULT(ic)));
1320 if (pdone > 1) break;
1323 /* had to position more than once GIVE UP */
1325 /* UNDO all the changes we made to try this */
1327 for (i=0; i < sym->nRegs ; i++ ) {
1328 sym->regs[i] = NULL;
1331 D(printf ("Fill Gap gave up due to positioning for %s in function %s\n",sym->name, currFunc ? currFunc->name : "UNKNOWN"));
1334 D(printf ("FILLED GAP for %s in function %s\n",sym->name, currFunc ? currFunc->name : "UNKNOWN"));
1335 _G.totRegAssigned = bitVectSetBit(_G.totRegAssigned,sym->key);
1336 sym->isspilt = sym->spillA = 0 ;
1337 sym->usl.spillLoc->allocreq--;
1342 /*-----------------------------------------------------------------*/
1343 /* rUmaskForOp :- returns register mask for an operand */
1344 /*-----------------------------------------------------------------*/
1346 mcs51_rUmaskForOp (operand * op)
1352 /* only temporaries are assigned registers */
1356 sym = OP_SYMBOL (op);
1358 /* if spilt or no registers assigned to it
1360 if (sym->isspilt || !sym->nRegs)
1363 rumask = newBitVect (mcs51_nRegs);
1365 for (j = 0; j < sym->nRegs; j++)
1367 rumask = bitVectSetBit (rumask,
1368 sym->regs[j]->rIdx);
1374 /*-----------------------------------------------------------------*/
1375 /* regsUsedIniCode :- returns bit vector of registers used in iCode */
1376 /*-----------------------------------------------------------------*/
1378 regsUsedIniCode (iCode * ic)
1380 bitVect *rmask = newBitVect (mcs51_nRegs);
1382 /* do the special cases first */
1385 rmask = bitVectUnion (rmask,
1386 mcs51_rUmaskForOp (IC_COND (ic)));
1390 /* for the jumptable */
1391 if (ic->op == JUMPTABLE)
1393 rmask = bitVectUnion (rmask,
1394 mcs51_rUmaskForOp (IC_JTCOND (ic)));
1399 /* of all other cases */
1401 rmask = bitVectUnion (rmask,
1402 mcs51_rUmaskForOp (IC_LEFT (ic)));
1406 rmask = bitVectUnion (rmask,
1407 mcs51_rUmaskForOp (IC_RIGHT (ic)));
1410 rmask = bitVectUnion (rmask,
1411 mcs51_rUmaskForOp (IC_RESULT (ic)));
1417 /*-----------------------------------------------------------------*/
1418 /* createRegMask - for each instruction will determine the regsUsed */
1419 /*-----------------------------------------------------------------*/
1421 createRegMask (eBBlock ** ebbs, int count)
1425 /* for all blocks */
1426 for (i = 0; i < count; i++)
1430 if (ebbs[i]->noPath &&
1431 (ebbs[i]->entryLabel != entryLabel &&
1432 ebbs[i]->entryLabel != returnLabel))
1435 /* for all instructions */
1436 for (ic = ebbs[i]->sch; ic; ic = ic->next)
1441 if (SKIP_IC2 (ic) || !ic->rlive)
1444 /* first mark the registers used in this
1446 ic->rUsed = regsUsedIniCode (ic);
1447 _G.funcrUsed = bitVectUnion (_G.funcrUsed, ic->rUsed);
1449 /* now create the register mask for those
1450 registers that are in use : this is a
1451 super set of ic->rUsed */
1452 ic->rMask = newBitVect (mcs51_nRegs + 1);
1454 /* for all live Ranges alive at this point */
1455 for (j = 1; j < ic->rlive->size; j++)
1460 /* if not alive then continue */
1461 if (!bitVectBitValue (ic->rlive, j))
1464 /* find the live range we are interested in */
1465 if (!(sym = hTabItemWithKey (liveRanges, j)))
1467 werror (E_INTERNAL_ERROR, __FILE__, __LINE__,
1468 "createRegMask cannot find live range");
1472 /* if no register assigned to it */
1473 if (!sym->nRegs || sym->isspilt)
1476 /* for all the registers allocated to it */
1477 for (k = 0; k < sym->nRegs; k++)
1480 bitVectSetBit (ic->rMask, sym->regs[k]->rIdx);
1486 /*-----------------------------------------------------------------*/
1487 /* rematStr - returns the rematerialized string for a remat var */
1488 /*-----------------------------------------------------------------*/
1490 rematStr (symbol * sym)
1493 iCode *ic = sym->rematiCode;
1498 /* if plus or minus print the right hand side */
1499 if (ic->op == '+' || ic->op == '-')
1501 sprintf (s, "0x%04x %c ", (int) operandLitValue (IC_RIGHT (ic)),
1504 ic = OP_SYMBOL (IC_LEFT (ic))->rematiCode;
1508 /* cast then continue */
1509 if (IS_CAST_ICODE(ic)) {
1510 ic = OP_SYMBOL (IC_RIGHT (ic))->rematiCode;
1513 /* we reached the end */
1514 sprintf (s, "%s", OP_SYMBOL (IC_LEFT (ic))->rname);
1521 /*-----------------------------------------------------------------*/
1522 /* regTypeNum - computes the type & number of registers required */
1523 /*-----------------------------------------------------------------*/
1525 regTypeNum (eBBlock *ebbs)
1531 /* for each live range do */
1532 for (sym = hTabFirstItem (liveRanges, &k); sym;
1533 sym = hTabNextItem (liveRanges, &k))
1536 /* if used zero times then no registers needed */
1537 if ((sym->liveTo - sym->liveFrom) == 0)
1541 /* if the live range is a temporary */
1545 /* if the type is marked as a conditional */
1546 if (sym->regType == REG_CND)
1549 /* if used in return only then we don't
1551 if (sym->ruonly || sym->accuse)
1553 if (IS_AGGREGATE (sym->type) || sym->isptr)
1554 sym->type = aggrToPtr (sym->type, FALSE);
1558 /* if the symbol has only one definition &
1559 that definition is a get_pointer */
1560 if (bitVectnBitsOn (sym->defs) == 1 &&
1561 (ic = hTabItemWithKey (iCodehTab,
1562 bitVectFirstBit (sym->defs))) &&
1565 !IS_BITVAR (sym->etype))
1569 /* and that pointer is remat in data space */
1570 if (OP_SYMBOL (IC_LEFT (ic))->remat &&
1571 !IS_CAST_ICODE(OP_SYMBOL (IC_LEFT (ic))->rematiCode) &&
1572 DCL_TYPE (aggrToPtr (operandType(IC_LEFT(ic)), FALSE)) == POINTER)
1574 /* create a psuedo symbol & force a spil */
1575 symbol *psym = newSymbol (rematStr (OP_SYMBOL (IC_LEFT (ic))), 1);
1576 psym->type = sym->type;
1577 psym->etype = sym->etype;
1578 strcpy (psym->rname, psym->name);
1580 sym->usl.spillLoc = psym;
1581 #if 0 // an alternative fix for bug #480076
1582 /* now this is a useless assignment to itself */
1583 remiCodeFromeBBlock (ebbs, ic);
1585 /* now this really is an assignment to itself, make it so;
1586 it will be optimized out later */
1588 IC_RIGHT(ic)=IC_RESULT(ic);
1594 /* if in data space or idata space then try to
1595 allocate pointer register */
1599 /* if not then we require registers */
1600 sym->nRegs = ((IS_AGGREGATE (sym->type) || sym->isptr) ?
1601 getSize (sym->type = aggrToPtr (sym->type, FALSE)) :
1602 getSize (sym->type));
1606 fprintf (stderr, "allocated more than 4 or 0 registers for type ");
1607 printTypeChain (sym->type, stderr);
1608 fprintf (stderr, "\n");
1611 /* determine the type of register required */
1612 if (sym->nRegs == 1 &&
1613 IS_PTR (sym->type) &&
1615 sym->regType = REG_PTR;
1617 sym->regType = REG_GPR;
1621 /* for the first run we don't provide */
1622 /* registers for true symbols we will */
1623 /* see how things go */
1629 /*-----------------------------------------------------------------*/
1630 /* freeAllRegs - mark all registers as free */
1631 /*-----------------------------------------------------------------*/
1637 for (i = 0; i < mcs51_nRegs; i++)
1638 regs8051[i].isFree = 1;
1641 /*-----------------------------------------------------------------*/
1642 /* deallocStackSpil - this will set the stack pointer back */
1643 /*-----------------------------------------------------------------*/
1645 DEFSETFUNC (deallocStackSpil)
1653 /*-----------------------------------------------------------------*/
1654 /* farSpacePackable - returns the packable icode for far variables */
1655 /*-----------------------------------------------------------------*/
1657 farSpacePackable (iCode * ic)
1661 /* go thru till we find a definition for the
1662 symbol on the right */
1663 for (dic = ic->prev; dic; dic = dic->prev)
1665 /* if the definition is a call then no */
1666 if ((dic->op == CALL || dic->op == PCALL) &&
1667 IC_RESULT (dic)->key == IC_RIGHT (ic)->key)
1672 /* if shift by unknown amount then not */
1673 if ((dic->op == LEFT_OP || dic->op == RIGHT_OP) &&
1674 IC_RESULT (dic)->key == IC_RIGHT (ic)->key)
1677 /* if pointer get and size > 1 */
1678 if (POINTER_GET (dic) &&
1679 getSize (aggrToPtr (operandType (IC_LEFT (dic)), FALSE)) > 1)
1682 if (POINTER_SET (dic) &&
1683 getSize (aggrToPtr (operandType (IC_RESULT (dic)), FALSE)) > 1)
1686 /* if any three is a true symbol in far space */
1687 if (IC_RESULT (dic) &&
1688 IS_TRUE_SYMOP (IC_RESULT (dic)) &&
1689 isOperandInFarSpace (IC_RESULT (dic)))
1692 if (IC_RIGHT (dic) &&
1693 IS_TRUE_SYMOP (IC_RIGHT (dic)) &&
1694 isOperandInFarSpace (IC_RIGHT (dic)) &&
1695 !isOperandEqual (IC_RIGHT (dic), IC_RESULT (ic)))
1698 if (IC_LEFT (dic) &&
1699 IS_TRUE_SYMOP (IC_LEFT (dic)) &&
1700 isOperandInFarSpace (IC_LEFT (dic)) &&
1701 !isOperandEqual (IC_LEFT (dic), IC_RESULT (ic)))
1704 if (isOperandEqual (IC_RIGHT (ic), IC_RESULT (dic)))
1706 if ((dic->op == LEFT_OP ||
1707 dic->op == RIGHT_OP ||
1709 IS_OP_LITERAL (IC_RIGHT (dic)))
1719 /*-----------------------------------------------------------------*/
1720 /* packRegsForAssign - register reduction for assignment */
1721 /*-----------------------------------------------------------------*/
1723 packRegsForAssign (iCode * ic, eBBlock * ebp)
1726 //sym_link *etype = operandType (IC_RIGHT (ic));
1728 if (!IS_ITEMP (IC_RIGHT (ic)) ||
1729 OP_SYMBOL (IC_RIGHT (ic))->isind ||
1730 OP_LIVETO (IC_RIGHT (ic)) > ic->seq
1731 /* why? || IS_BITFIELD (etype) */ )
1736 /* if the true symbol is defined in far space or on stack
1737 then we should not since this will increase register pressure */
1738 if (isOperandInFarSpace(IC_RESULT(ic)) && !farSpacePackable(ic)) {
1742 /* find the definition of iTempNN scanning backwards if we find a
1743 a use of the true symbol in before we find the definition then
1745 for (dic = ic->prev; dic; dic = dic->prev)
1747 /* if there is a function call then don't pack it */
1748 if ((dic->op == CALL || dic->op == PCALL))
1757 if (IS_TRUE_SYMOP (IC_RESULT (dic)) &&
1758 IS_OP_VOLATILE (IC_RESULT (dic)))
1764 if (IS_SYMOP (IC_RESULT (dic)) &&
1765 IC_RESULT (dic)->key == IC_RIGHT (ic)->key)
1767 if (POINTER_SET (dic))
1773 if (IS_SYMOP (IC_RIGHT (dic)) &&
1774 (IC_RIGHT (dic)->key == IC_RESULT (ic)->key ||
1775 IC_RIGHT (dic)->key == IC_RIGHT (ic)->key))
1781 if (IS_SYMOP (IC_LEFT (dic)) &&
1782 (IC_LEFT (dic)->key == IC_RESULT (ic)->key ||
1783 IC_LEFT (dic)->key == IC_RIGHT (ic)->key))
1789 if (POINTER_SET (dic) &&
1790 IC_RESULT (dic)->key == IC_RESULT (ic)->key)
1798 return 0; /* did not find */
1800 /* if assignment then check that right is not a bit */
1801 if (ASSIGNMENT (dic) && !POINTER_SET (dic))
1803 sym_link *etype = operandType (IC_RIGHT (dic));
1804 if (IS_BITFIELD (etype))
1807 /* if the result is on stack or iaccess then it must be
1808 the same atleast one of the operands */
1809 if (OP_SYMBOL (IC_RESULT (ic))->onStack ||
1810 OP_SYMBOL (IC_RESULT (ic))->iaccess)
1813 /* the operation has only one symbol
1814 operator then we can pack */
1815 if ((IC_LEFT (dic) && !IS_SYMOP (IC_LEFT (dic))) ||
1816 (IC_RIGHT (dic) && !IS_SYMOP (IC_RIGHT (dic))))
1819 if (!((IC_LEFT (dic) &&
1820 IC_RESULT (ic)->key == IC_LEFT (dic)->key) ||
1822 IC_RESULT (ic)->key == IC_RIGHT (dic)->key)))
1826 /* found the definition */
1827 /* replace the result with the result of */
1828 /* this assignment and remove this assignment */
1829 bitVectUnSetBit(OP_SYMBOL(IC_RESULT(dic))->defs,dic->key);
1830 IC_RESULT (dic) = IC_RESULT (ic);
1832 if (IS_ITEMP (IC_RESULT (dic)) && OP_SYMBOL (IC_RESULT (dic))->liveFrom > dic->seq)
1834 OP_SYMBOL (IC_RESULT (dic))->liveFrom = dic->seq;
1836 /* delete from liverange table also
1837 delete from all the points inbetween and the new
1839 for (sic = dic; sic != ic; sic = sic->next)
1841 bitVectUnSetBit (sic->rlive, IC_RESULT (ic)->key);
1842 if (IS_ITEMP (IC_RESULT (dic)))
1843 bitVectSetBit (sic->rlive, IC_RESULT (dic)->key);
1846 remiCodeFromeBBlock (ebp, ic);
1847 bitVectUnSetBit(OP_SYMBOL(IC_RESULT(ic))->defs,ic->key);
1848 hTabDeleteItem (&iCodehTab, ic->key, ic, DELETE_ITEM, NULL);
1849 OP_DEFS (IC_RESULT (dic)) = bitVectSetBit (OP_DEFS (IC_RESULT (dic)), dic->key);
1854 /*-----------------------------------------------------------------*/
1855 /* findAssignToSym : scanning backwards looks for first assig found */
1856 /*-----------------------------------------------------------------*/
1858 findAssignToSym (operand * op, iCode * ic)
1862 for (dic = ic->prev; dic; dic = dic->prev)
1865 /* if definition by assignment */
1866 if (dic->op == '=' &&
1867 !POINTER_SET (dic) &&
1868 IC_RESULT (dic)->key == op->key
1869 /* && IS_TRUE_SYMOP(IC_RIGHT(dic)) */
1873 /* we are interested only if defined in far space */
1874 /* or in stack space in case of + & - */
1876 /* if assigned to a non-symbol then return
1878 if (!IS_SYMOP (IC_RIGHT (dic)))
1881 /* if the symbol is in far space then
1883 if (isOperandInFarSpace (IC_RIGHT (dic)))
1886 /* for + & - operations make sure that
1887 if it is on the stack it is the same
1888 as one of the three operands */
1889 if ((ic->op == '+' || ic->op == '-') &&
1890 OP_SYMBOL (IC_RIGHT (dic))->onStack)
1893 if (IC_RESULT (ic)->key != IC_RIGHT (dic)->key &&
1894 IC_LEFT (ic)->key != IC_RIGHT (dic)->key &&
1895 IC_RIGHT (ic)->key != IC_RIGHT (dic)->key)
1903 /* if we find an usage then we cannot delete it */
1904 if (IC_LEFT (dic) && IC_LEFT (dic)->key == op->key)
1907 if (IC_RIGHT (dic) && IC_RIGHT (dic)->key == op->key)
1910 if (POINTER_SET (dic) && IC_RESULT (dic)->key == op->key)
1914 /* now make sure that the right side of dic
1915 is not defined between ic & dic */
1918 iCode *sic = dic->next;
1920 for (; sic != ic; sic = sic->next)
1921 if (IC_RESULT (sic) &&
1922 IC_RESULT (sic)->key == IC_RIGHT (dic)->key)
1931 /*-----------------------------------------------------------------*/
1932 /* packRegsForSupport :- reduce some registers for support calls */
1933 /*-----------------------------------------------------------------*/
1935 packRegsForSupport (iCode * ic, eBBlock * ebp)
1940 /* for the left & right operand :- look to see if the
1941 left was assigned a true symbol in far space in that
1942 case replace them */
1944 if (IS_ITEMP (IC_LEFT (ic)) &&
1945 OP_SYMBOL (IC_LEFT (ic))->liveTo <= ic->seq)
1947 dic = findAssignToSym (IC_LEFT (ic), ic);
1952 /* found it we need to remove it from the
1954 for (sic = dic; sic != ic; sic = sic->next) {
1955 bitVectUnSetBit (sic->rlive, IC_LEFT (ic)->key);
1956 sic->rlive = bitVectSetBit (sic->rlive, IC_RIGHT (dic)->key);
1959 OP_SYMBOL(IC_LEFT (ic))=OP_SYMBOL(IC_RIGHT (dic));
1960 OP_SYMBOL(IC_LEFT(ic))->liveTo = ic->seq;
1961 IC_LEFT (ic)->key = OP_SYMBOL(IC_RIGHT (dic))->key;
1962 remiCodeFromeBBlock (ebp, dic);
1963 bitVectUnSetBit(OP_SYMBOL(IC_RESULT(dic))->defs,dic->key);
1964 hTabDeleteItem (&iCodehTab, dic->key, dic, DELETE_ITEM, NULL);
1968 /* do the same for the right operand */
1971 IS_ITEMP (IC_RIGHT (ic)) &&
1972 OP_SYMBOL (IC_RIGHT (ic))->liveTo <= ic->seq)
1974 iCode *dic = findAssignToSym (IC_RIGHT (ic), ic);
1980 /* if this is a subtraction & the result
1981 is a true symbol in far space then don't pack */
1982 if (ic->op == '-' && IS_TRUE_SYMOP (IC_RESULT (dic)))
1984 sym_link *etype = getSpec (operandType (IC_RESULT (dic)));
1985 if (IN_FARSPACE (SPEC_OCLS (etype)))
1988 /* found it we need to remove it from the
1990 for (sic = dic; sic != ic; sic = sic->next) {
1991 bitVectUnSetBit (sic->rlive, IC_RIGHT (ic)->key);
1992 sic->rlive = bitVectSetBit (sic->rlive, IC_RIGHT (dic)->key);
1995 IC_RIGHT (ic)->operand.symOperand =
1996 IC_RIGHT (dic)->operand.symOperand;
1997 OP_SYMBOL(IC_RIGHT(ic))->liveTo = ic->seq;
1998 IC_RIGHT (ic)->key = IC_RIGHT (dic)->operand.symOperand->key;
2000 remiCodeFromeBBlock (ebp, dic);
2001 bitVectUnSetBit(OP_SYMBOL(IC_RESULT(dic))->defs,dic->key);
2002 hTabDeleteItem (&iCodehTab, dic->key, dic, DELETE_ITEM, NULL);
2009 #define IS_OP_RUONLY(x) (x && IS_SYMOP(x) && OP_SYMBOL(x)->ruonly)
2012 /*-----------------------------------------------------------------*/
2013 /* packRegsForOneuse : - will reduce some registers for single Use */
2014 /*-----------------------------------------------------------------*/
2016 packRegsForOneuse (iCode * ic, operand * op, eBBlock * ebp)
2021 /* if returning a literal then do nothing */
2025 /* only upto 2 bytes since we cannot predict
2026 the usage of b, & acc */
2027 if (getSize (operandType (op)) > (fReturnSizeMCS51 - 2))
2030 if (ic->op != RETURN &&
2032 !POINTER_SET (ic) &&
2036 if (ic->op == SEND && ic->argreg != 1) return NULL;
2038 /* this routine will mark the a symbol as used in one
2039 instruction use only && if the defintion is local
2040 (ie. within the basic block) && has only one definition &&
2041 that definiion is either a return value from a
2042 function or does not contain any variables in
2044 uses = bitVectCopy (OP_USES (op));
2045 bitVectUnSetBit (uses, ic->key); /* take away this iCode */
2046 if (!bitVectIsZero (uses)) /* has other uses */
2049 /* if it has only one defintion */
2050 if (bitVectnBitsOn (OP_DEFS (op)) > 1)
2051 return NULL; /* has more than one definition */
2053 /* get that definition */
2055 hTabItemWithKey (iCodehTab,
2056 bitVectFirstBit (OP_DEFS (op)))))
2059 /* if that only usage is a cast */
2060 if (dic->op == CAST) {
2061 /* to a bigger type */
2062 if (getSize(OP_SYM_TYPE(IC_RESULT(dic))) >
2063 getSize(OP_SYM_TYPE(IC_RIGHT(dic)))) {
2064 /* than we can not, since we cannot predict the usage of b & acc */
2069 /* found the definition now check if it is local */
2070 if (dic->seq < ebp->fSeq ||
2071 dic->seq > ebp->lSeq)
2072 return NULL; /* non-local */
2074 /* now check if it is the return from
2076 if (dic->op == CALL || dic->op == PCALL)
2078 if (ic->op != SEND && ic->op != RETURN &&
2079 !POINTER_SET(ic) && !POINTER_GET(ic))
2081 OP_SYMBOL (op)->ruonly = 1;
2088 /* otherwise check that the definition does
2089 not contain any symbols in far space */
2090 if (isOperandInFarSpace (IC_LEFT (dic)) ||
2091 isOperandInFarSpace (IC_RIGHT (dic)) ||
2092 IS_OP_RUONLY (IC_LEFT (ic)) ||
2093 IS_OP_RUONLY (IC_RIGHT (ic)))
2098 /* if pointer set then make sure the pointer
2100 if (POINTER_SET (dic) &&
2101 !IS_DATA_PTR (aggrToPtr (operandType (IC_RESULT (dic)), FALSE)))
2104 if (POINTER_GET (dic) &&
2105 !IS_DATA_PTR (aggrToPtr (operandType (IC_LEFT (dic)), FALSE)))
2110 /* also make sure the intervenening instructions
2111 don't have any thing in far space */
2112 for (dic = dic->next; dic && dic != ic && sic != ic; dic = dic->next)
2115 /* if there is an intervening function call then no */
2116 if (dic->op == CALL || dic->op == PCALL)
2118 /* if pointer set then make sure the pointer
2120 if (POINTER_SET (dic) &&
2121 !IS_DATA_PTR (aggrToPtr (operandType (IC_RESULT (dic)), FALSE)))
2124 if (POINTER_GET (dic) &&
2125 !IS_DATA_PTR (aggrToPtr (operandType (IC_LEFT (dic)), FALSE)))
2128 /* if address of & the result is remat the okay */
2129 if (dic->op == ADDRESS_OF &&
2130 OP_SYMBOL (IC_RESULT (dic))->remat)
2133 /* if operand has size of three or more & this
2134 operation is a '*','/' or '%' then 'b' may
2136 if ((dic->op == '%' || dic->op == '/' || dic->op == '*') &&
2137 getSize (operandType (op)) >= 3)
2140 /* if left or right or result is in far space */
2141 if (isOperandInFarSpace (IC_LEFT (dic)) ||
2142 isOperandInFarSpace (IC_RIGHT (dic)) ||
2143 isOperandInFarSpace (IC_RESULT (dic)) ||
2144 IS_OP_RUONLY (IC_LEFT (dic)) ||
2145 IS_OP_RUONLY (IC_RIGHT (dic)) ||
2146 IS_OP_RUONLY (IC_RESULT (dic)))
2150 /* if left or right or result is on stack */
2151 if (isOperandOnStack(IC_LEFT(dic)) ||
2152 isOperandOnStack(IC_RIGHT(dic)) ||
2153 isOperandOnStack(IC_RESULT(dic))) {
2158 OP_SYMBOL (op)->ruonly = 1;
2163 /*-----------------------------------------------------------------*/
2164 /* isBitwiseOptimizable - requirements of JEAN LOUIS VERN */
2165 /*-----------------------------------------------------------------*/
2167 isBitwiseOptimizable (iCode * ic)
2169 sym_link *ltype = getSpec (operandType (IC_LEFT (ic)));
2170 sym_link *rtype = getSpec (operandType (IC_RIGHT (ic)));
2172 /* bitwise operations are considered optimizable
2173 under the following conditions (Jean-Louis VERN)
2185 if (IS_LITERAL(rtype) ||
2186 (IS_BITVAR (ltype) && IN_BITSPACE (SPEC_OCLS (ltype))))
2192 /*-----------------------------------------------------------------*/
2193 /* packRegsForAccUse - pack registers for acc use */
2194 /*-----------------------------------------------------------------*/
2196 packRegsForAccUse (iCode * ic)
2200 /* if this is an aggregate, e.g. a one byte char array */
2201 if (IS_AGGREGATE(operandType(IC_RESULT(ic)))) {
2205 /* if we are calling a reentrant function that has stack parameters */
2206 if (ic->op == CALL &&
2207 IFFUNC_ISREENT(operandType(IC_LEFT(ic))) &&
2208 FUNC_HASSTACKPARM(operandType(IC_LEFT(ic))))
2211 if (ic->op == PCALL &&
2212 IFFUNC_ISREENT(operandType(IC_LEFT(ic))->next) &&
2213 FUNC_HASSTACKPARM(operandType(IC_LEFT(ic))->next))
2216 /* if + or - then it has to be one byte result */
2217 if ((ic->op == '+' || ic->op == '-')
2218 && getSize (operandType (IC_RESULT (ic))) > 1)
2221 /* if shift operation make sure right side is not a literal */
2222 if (ic->op == RIGHT_OP &&
2223 (isOperandLiteral (IC_RIGHT (ic)) ||
2224 getSize (operandType (IC_RESULT (ic))) > 1))
2227 if (ic->op == LEFT_OP &&
2228 (isOperandLiteral (IC_RIGHT (ic)) ||
2229 getSize (operandType (IC_RESULT (ic))) > 1))
2232 if (IS_BITWISE_OP (ic) &&
2233 getSize (operandType (IC_RESULT (ic))) > 1)
2237 /* has only one definition */
2238 if (bitVectnBitsOn (OP_DEFS (IC_RESULT (ic))) > 1)
2241 /* has only one use */
2242 if (bitVectnBitsOn (OP_USES (IC_RESULT (ic))) > 1)
2245 /* and the usage immediately follows this iCode */
2246 if (!(uic = hTabItemWithKey (iCodehTab,
2247 bitVectFirstBit (OP_USES (IC_RESULT (ic))))))
2250 if (ic->next != uic)
2253 /* if it is a conditional branch then we definitely can */
2257 if (uic->op == JUMPTABLE)
2260 /* if the usage is not is an assignment
2261 or an arithmetic / bitwise / shift operation then not */
2262 if (POINTER_SET (uic) &&
2263 getSize (aggrToPtr (operandType (IC_RESULT (uic)), FALSE)) > 1)
2266 if (uic->op != '=' &&
2267 !IS_ARITHMETIC_OP (uic) &&
2268 !IS_BITWISE_OP (uic) &&
2269 uic->op != LEFT_OP &&
2270 uic->op != RIGHT_OP)
2273 /* if used in ^ operation then make sure right is not a
2275 if (uic->op == '^' && isOperandLiteral (IC_RIGHT (uic)))
2278 /* if shift operation make sure right side is not a literal */
2279 if (uic->op == RIGHT_OP &&
2280 (isOperandLiteral (IC_RIGHT (uic)) ||
2281 getSize (operandType (IC_RESULT (uic))) > 1))
2284 if (uic->op == LEFT_OP &&
2285 (isOperandLiteral (IC_RIGHT (uic)) ||
2286 getSize (operandType (IC_RESULT (uic))) > 1))
2289 /* make sure that the result of this icode is not on the
2290 stack, since acc is used to compute stack offset */
2292 if (IS_TRUE_SYMOP (IC_RESULT (uic)) &&
2293 OP_SYMBOL (IC_RESULT (uic))->onStack)
2296 if (isOperandOnStack(IC_RESULT(uic)))
2300 /* if either one of them in far space then we cannot */
2301 if ((IS_TRUE_SYMOP (IC_LEFT (uic)) &&
2302 isOperandInFarSpace (IC_LEFT (uic))) ||
2303 (IS_TRUE_SYMOP (IC_RIGHT (uic)) &&
2304 isOperandInFarSpace (IC_RIGHT (uic))))
2307 /* if the usage has only one operand then we can */
2308 if (IC_LEFT (uic) == NULL ||
2309 IC_RIGHT (uic) == NULL)
2312 /* make sure this is on the left side if not
2313 a '+' since '+' is commutative */
2314 if (ic->op != '+' &&
2315 IC_LEFT (uic)->key != IC_RESULT (ic)->key)
2319 // this is too dangerous and need further restrictions
2322 /* if one of them is a literal then we can */
2323 if ((IC_LEFT (uic) && IS_OP_LITERAL (IC_LEFT (uic))) ||
2324 (IC_RIGHT (uic) && IS_OP_LITERAL (IC_RIGHT (uic))))
2326 OP_SYMBOL (IC_RESULT (ic))->accuse = 1;
2331 /* if the other one is not on stack then we can */
2332 if (IC_LEFT (uic)->key == IC_RESULT (ic)->key &&
2333 (IS_ITEMP (IC_RIGHT (uic)) ||
2334 (IS_TRUE_SYMOP (IC_RIGHT (uic)) &&
2335 !OP_SYMBOL (IC_RIGHT (uic))->onStack)))
2338 if (IC_RIGHT (uic)->key == IC_RESULT (ic)->key &&
2339 (IS_ITEMP (IC_LEFT (uic)) ||
2340 (IS_TRUE_SYMOP (IC_LEFT (uic)) &&
2341 !OP_SYMBOL (IC_LEFT (uic))->onStack)))
2347 OP_SYMBOL (IC_RESULT (ic))->accuse = 1;
2352 /*-----------------------------------------------------------------*/
2353 /* packForPush - hueristics to reduce iCode for pushing */
2354 /*-----------------------------------------------------------------*/
2356 packForPush (iCode * ic, eBBlock * ebp)
2361 if (ic->op != IPUSH || !IS_ITEMP (IC_LEFT (ic)))
2364 /* must have only definition & one usage */
2365 if (bitVectnBitsOn (OP_DEFS (IC_LEFT (ic))) != 1 ||
2366 bitVectnBitsOn (OP_USES (IC_LEFT (ic))) != 1)
2369 /* find the definition */
2370 if (!(dic = hTabItemWithKey (iCodehTab,
2371 bitVectFirstBit (OP_DEFS (IC_LEFT (ic))))))
2374 if (dic->op != '=' || POINTER_SET (dic))
2377 /* make sure the right side does not have any definitions
2379 dbv = OP_DEFS(IC_RIGHT(dic));
2380 for (lic = ic; lic && lic != dic ; lic = lic->prev) {
2381 if (bitVectBitValue(dbv,lic->key))
2384 /* make sure they have the same type */
2386 sym_link *itype=operandType(IC_LEFT(ic));
2387 sym_link *ditype=operandType(IC_RIGHT(dic));
2389 if (SPEC_USIGN(itype)!=SPEC_USIGN(ditype) ||
2390 SPEC_LONG(itype)!=SPEC_LONG(ditype))
2393 /* extend the live range of replaced operand if needed */
2394 if (OP_SYMBOL(IC_RIGHT(dic))->liveTo < ic->seq) {
2395 OP_SYMBOL(IC_RIGHT(dic))->liveTo = ic->seq;
2397 /* we now we know that it has one & only one def & use
2398 and the that the definition is an assignment */
2399 IC_LEFT (ic) = IC_RIGHT (dic);
2401 remiCodeFromeBBlock (ebp, dic);
2402 bitVectUnSetBit(OP_SYMBOL(IC_RESULT(dic))->defs,dic->key);
2403 hTabDeleteItem (&iCodehTab, dic->key, dic, DELETE_ITEM, NULL);
2406 /*-----------------------------------------------------------------*/
2407 /* packRegisters - does some transformations to reduce register */
2409 /*-----------------------------------------------------------------*/
2411 packRegisters (eBBlock * ebp)
2421 /* look for assignments of the form */
2422 /* iTempNN = TRueSym (someoperation) SomeOperand */
2424 /* TrueSym := iTempNN:1 */
2425 for (ic = ebp->sch; ic; ic = ic->next)
2427 /* find assignment of the form TrueSym := iTempNN:1 */
2428 if (ic->op == '=' && !POINTER_SET (ic))
2429 change += packRegsForAssign (ic, ebp);
2436 for (ic = ebp->sch; ic; ic = ic->next)
2438 /* if this is an itemp & result of an address of a true sym
2439 then mark this as rematerialisable */
2440 if (ic->op == ADDRESS_OF &&
2441 IS_ITEMP (IC_RESULT (ic)) &&
2442 IS_TRUE_SYMOP (IC_LEFT (ic)) &&
2443 bitVectnBitsOn (OP_DEFS (IC_RESULT (ic))) == 1 &&
2444 !OP_SYMBOL (IC_LEFT (ic))->onStack)
2447 OP_SYMBOL (IC_RESULT (ic))->remat = 1;
2448 OP_SYMBOL (IC_RESULT (ic))->rematiCode = ic;
2449 OP_SYMBOL (IC_RESULT (ic))->usl.spillLoc = NULL;
2453 /* if straight assignment then carry remat flag if
2454 this is the only definition */
2455 if (ic->op == '=' &&
2456 !POINTER_SET (ic) &&
2457 IS_SYMOP (IC_RIGHT (ic)) &&
2458 OP_SYMBOL (IC_RIGHT (ic))->remat &&
2459 !IS_CAST_ICODE(OP_SYMBOL (IC_RIGHT (ic))->rematiCode) &&
2460 bitVectnBitsOn (OP_SYMBOL (IC_RESULT (ic))->defs) <= 1)
2463 OP_SYMBOL (IC_RESULT (ic))->remat =
2464 OP_SYMBOL (IC_RIGHT (ic))->remat;
2465 OP_SYMBOL (IC_RESULT (ic))->rematiCode =
2466 OP_SYMBOL (IC_RIGHT (ic))->rematiCode;
2469 /* if cast to a generic pointer & the pointer being
2470 cast is remat, then we can remat this cast as well */
2471 if (ic->op == CAST &&
2472 IS_SYMOP(IC_RIGHT(ic)) &&
2473 OP_SYMBOL(IC_RIGHT(ic))->remat ) {
2474 sym_link *to_type = operandType(IC_LEFT(ic));
2475 sym_link *from_type = operandType(IC_RIGHT(ic));
2476 if (IS_GENPTR(to_type) && IS_PTR(from_type)) {
2477 OP_SYMBOL (IC_RESULT (ic))->remat = 1;
2478 OP_SYMBOL (IC_RESULT (ic))->rematiCode = ic;
2479 OP_SYMBOL (IC_RESULT (ic))->usl.spillLoc = NULL;
2483 /* if this is a +/- operation with a rematerizable
2484 then mark this as rematerializable as well */
2485 if ((ic->op == '+' || ic->op == '-') &&
2486 (IS_SYMOP (IC_LEFT (ic)) &&
2487 IS_ITEMP (IC_RESULT (ic)) &&
2488 IS_OP_LITERAL (IC_RIGHT (ic))) &&
2489 OP_SYMBOL (IC_LEFT (ic))->remat &&
2490 (!IS_SYMOP (IC_RIGHT (ic)) || !IS_CAST_ICODE(OP_SYMBOL (IC_RIGHT (ic))->rematiCode)) &&
2491 bitVectnBitsOn (OP_DEFS (IC_RESULT (ic))) == 1)
2493 OP_SYMBOL (IC_RESULT (ic))->remat = 1;
2494 OP_SYMBOL (IC_RESULT (ic))->rematiCode = ic;
2495 OP_SYMBOL (IC_RESULT (ic))->usl.spillLoc = NULL;
2498 /* mark the pointer usages */
2499 if (POINTER_SET (ic))
2500 OP_SYMBOL (IC_RESULT (ic))->uptr = 1;
2502 if (POINTER_GET (ic))
2503 OP_SYMBOL (IC_LEFT (ic))->uptr = 1;
2507 /* if we are using a symbol on the stack
2508 then we should say mcs51_ptrRegReq */
2509 if (ic->op == IFX && IS_SYMOP (IC_COND (ic)))
2510 mcs51_ptrRegReq += ((OP_SYMBOL (IC_COND (ic))->onStack ||
2511 OP_SYMBOL (IC_COND (ic))->iaccess) ? 1 : 0);
2512 else if (ic->op == JUMPTABLE && IS_SYMOP (IC_JTCOND (ic)))
2513 mcs51_ptrRegReq += ((OP_SYMBOL (IC_JTCOND (ic))->onStack ||
2514 OP_SYMBOL (IC_JTCOND (ic))->iaccess) ? 1 : 0);
2517 if (IS_SYMOP (IC_LEFT (ic)))
2518 mcs51_ptrRegReq += ((OP_SYMBOL (IC_LEFT (ic))->onStack ||
2519 OP_SYMBOL (IC_LEFT (ic))->iaccess) ? 1 : 0);
2520 if (IS_SYMOP (IC_RIGHT (ic)))
2521 mcs51_ptrRegReq += ((OP_SYMBOL (IC_RIGHT (ic))->onStack ||
2522 OP_SYMBOL (IC_RIGHT (ic))->iaccess) ? 1 : 0);
2523 if (IS_SYMOP (IC_RESULT (ic)))
2524 mcs51_ptrRegReq += ((OP_SYMBOL (IC_RESULT (ic))->onStack ||
2525 OP_SYMBOL (IC_RESULT (ic))->iaccess) ? 1 : 0);
2529 /* if the condition of an if instruction
2530 is defined in the previous instruction and
2531 this is the only usage then
2532 mark the itemp as a conditional */
2533 if ((IS_CONDITIONAL (ic) ||
2534 (IS_BITWISE_OP(ic) && isBitwiseOptimizable (ic))) &&
2535 ic->next && ic->next->op == IFX &&
2536 bitVectnBitsOn (OP_USES(IC_RESULT(ic)))==1 &&
2537 isOperandEqual (IC_RESULT (ic), IC_COND (ic->next)) &&
2538 OP_SYMBOL (IC_RESULT (ic))->liveTo <= ic->next->seq)
2540 OP_SYMBOL (IC_RESULT (ic))->regType = REG_CND;
2544 /* reduce for support function calls */
2545 if (ic->supportRtn || ic->op == '+' || ic->op == '-')
2546 packRegsForSupport (ic, ebp);
2548 /* some cases the redundant moves can
2549 can be eliminated for return statements */
2550 if ((ic->op == RETURN || (ic->op == SEND && ic->argreg == 1)) &&
2551 !isOperandInFarSpace (IC_LEFT (ic)) &&
2552 options.model == MODEL_SMALL) {
2553 if (0 && options.stackAuto) {
2554 /* we should check here if acc will be clobbered for stack
2555 offset calculations */
2557 packRegsForOneuse (ic, IC_LEFT (ic), ebp);
2561 /* if pointer set & left has a size more than
2562 one and right is not in far space */
2563 if (POINTER_SET (ic) &&
2564 !isOperandInFarSpace (IC_RIGHT (ic)) &&
2565 !OP_SYMBOL (IC_RESULT (ic))->remat &&
2566 !IS_OP_RUONLY (IC_RIGHT (ic)) &&
2567 getSize (aggrToPtr (operandType (IC_RESULT (ic)), FALSE)) > 1)
2569 packRegsForOneuse (ic, IC_RESULT (ic), ebp);
2571 /* if pointer get */
2572 if (POINTER_GET (ic) &&
2573 !isOperandInFarSpace (IC_RESULT (ic)) &&
2574 !OP_SYMBOL (IC_LEFT (ic))->remat &&
2575 !IS_OP_RUONLY (IC_RESULT (ic)) &&
2576 getSize (aggrToPtr (operandType (IC_LEFT (ic)), FALSE)) > 1)
2578 packRegsForOneuse (ic, IC_LEFT (ic), ebp);
2581 /* if this is cast for intergral promotion then
2582 check if only use of the definition of the
2583 operand being casted/ if yes then replace
2584 the result of that arithmetic operation with
2585 this result and get rid of the cast */
2588 sym_link *fromType = operandType (IC_RIGHT (ic));
2589 sym_link *toType = operandType (IC_LEFT (ic));
2591 if (IS_INTEGRAL (fromType) && IS_INTEGRAL (toType) &&
2592 getSize (fromType) != getSize (toType) &&
2593 SPEC_USIGN (fromType) == SPEC_USIGN (toType))
2596 iCode *dic = packRegsForOneuse (ic, IC_RIGHT (ic), ebp);
2599 if (IS_ARITHMETIC_OP (dic))
2601 bitVectUnSetBit(OP_SYMBOL(IC_RESULT(dic))->defs,dic->key);
2602 IC_RESULT (dic) = IC_RESULT (ic);
2603 remiCodeFromeBBlock (ebp, ic);
2604 bitVectUnSetBit(OP_SYMBOL(IC_RESULT(ic))->defs,ic->key);
2605 hTabDeleteItem (&iCodehTab, ic->key, ic, DELETE_ITEM, NULL);
2606 OP_DEFS (IC_RESULT (dic)) = bitVectSetBit (OP_DEFS (IC_RESULT (dic)), dic->key);
2610 OP_SYMBOL (IC_RIGHT (ic))->ruonly = 0;
2616 /* if the type from and type to are the same
2617 then if this is the only use then packit */
2618 if (compareType (operandType (IC_RIGHT (ic)),
2619 operandType (IC_LEFT (ic))) == 1)
2621 iCode *dic = packRegsForOneuse (ic, IC_RIGHT (ic), ebp);
2624 bitVectUnSetBit(OP_SYMBOL(IC_RESULT(dic))->defs,dic->key);
2625 IC_RESULT (dic) = IC_RESULT (ic);
2626 remiCodeFromeBBlock (ebp, ic);
2627 bitVectUnSetBit(OP_SYMBOL(IC_RESULT(ic))->defs,ic->key);
2628 hTabDeleteItem (&iCodehTab, ic->key, ic, DELETE_ITEM, NULL);
2629 OP_DEFS (IC_RESULT (dic)) = bitVectSetBit (OP_DEFS (IC_RESULT (dic)), dic->key);
2637 iTempNN := (some variable in farspace) V1
2642 if (ic->op == IPUSH)
2644 packForPush (ic, ebp);
2648 /* pack registers for accumulator use, when the
2649 result of an arithmetic or bit wise operation
2650 has only one use, that use is immediately following
2651 the defintion and the using iCode has only one
2652 operand or has two operands but one is literal &
2653 the result of that operation is not on stack then
2654 we can leave the result of this operation in acc:b
2656 if ((IS_ARITHMETIC_OP (ic)
2657 || IS_CONDITIONAL(ic)
2658 || IS_BITWISE_OP (ic)
2659 || ic->op == LEFT_OP || ic->op == RIGHT_OP || ic->op == CALL
2660 || (ic->op == ADDRESS_OF && isOperandOnStack (IC_LEFT (ic)))
2662 IS_ITEMP (IC_RESULT (ic)) &&
2663 getSize (operandType (IC_RESULT (ic))) <= 2)
2665 packRegsForAccUse (ic);
2669 /*-----------------------------------------------------------------*/
2670 /* assignRegisters - assigns registers to each live range as need */
2671 /*-----------------------------------------------------------------*/
2673 mcs51_assignRegisters (eBBlock ** ebbs, int count)
2678 setToNull ((void *) &_G.funcrUsed);
2679 setToNull ((void *) &_G.totRegAssigned);
2680 mcs51_ptrRegReq = _G.stackExtend = _G.dataExtend = 0;
2683 /* change assignments this will remove some
2684 live ranges reducing some register pressure */
2685 for (i = 0; i < count; i++)
2686 packRegisters (ebbs[i]);
2688 if (options.dump_pack)
2689 dumpEbbsToFileExt (DUMP_PACK, ebbs, count);
2691 /* first determine for each live range the number of
2692 registers & the type of registers required for each */
2695 /* and serially allocate registers */
2696 serialRegAssign (ebbs, count);
2701 /* if stack was extended then tell the user */
2704 /* werror(W_TOOMANY_SPILS,"stack", */
2705 /* _G.stackExtend,currFunc->name,""); */
2711 /* werror(W_TOOMANY_SPILS,"data space", */
2712 /* _G.dataExtend,currFunc->name,""); */
2716 /* after that create the register mask
2717 for each of the instruction */
2718 createRegMask (ebbs, count);
2720 /* redo that offsets for stacked automatic variables */
2721 redoStackOffsets ();
2723 if (options.dump_rassgn)
2725 dumpEbbsToFileExt (DUMP_RASSGN, ebbs, count);
2726 dumpLiveRanges (DUMP_LRANGE, liveRanges);
2729 /* do the overlaysegment stuff SDCCmem.c */
2730 doOverlays (ebbs, count);
2732 /* now get back the chain */
2733 ic = iCodeLabelOptimize (iCodeFromeBBlock (ebbs, count));
2737 /* free up any _G.stackSpil locations allocated */
2738 applyToSet (_G.stackSpil, deallocStackSpil);
2740 setToNull ((void **) &_G.stackSpil);
2741 setToNull ((void **) &_G.spiltSet);
2742 /* mark all registers as free */