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-rw-r--r--ir/regalloc.c1417
1 files changed, 0 insertions, 1417 deletions
diff --git a/ir/regalloc.c b/ir/regalloc.c
deleted file mode 100644
index 1200c77..0000000
--- a/ir/regalloc.c
+++ /dev/null
@@ -1,1417 +0,0 @@
-#include "ir.h"
-
-/** Implements linear scan register allocation **/
-/* Some references:
- * Linear Scan Register Allocation on SSA Form (Wimmer 2010)
- - https://c9x.me/compile/bib/Wimmer10a.pdf
- * Linear Scan Register Allocation in the Context of SSA Form
- and Register Constraints (Mössenböck 2002)
- - https://bernsteinbear.com/assets/img/linear-scan-ra-context-ssa.pdf
- */
-
-#if 1
-#define DBG(...) if(ccopt.dbg.r) bfmt(ccopt.dbgout, __VA_ARGS__)
-#else
-#define DBG(...) ((void)0)
-#endif
-
-/* The algorithm used here to introduce phis for temporaries whose definitions
- * appear later than some of its uses is very similar to that in mem2reg() */
-
-static int livelastblk;
-struct pendingphi { ushort var, phi; };
-static vec_of(struct pendingphi) *pendingphis;
-static int npendingphi;
-static ushort **curdefs;
-static union ref readvar(struct bitset *defined, enum irclass cls, int var, struct block *blk);
-
-static void
-fillphi(struct bitset *defined, union ref phi, enum irclass cls, int var, struct block *blk)
-{
- union ref *args = phitab.p[instrtab[phi.i].l.i];
- assert(blk->npred > 0);
- for (int i = 0; i < blk->npred; ++i)
- args[i] = readvar(defined, cls, var, blk);
-}
-
-static union ref
-readvar(struct bitset *defined, enum irclass cls, int var, struct block *blk)
-{
- union ref val;
-
- if (bstest(defined, var)) return mkref(RTMP, var);
- assert(cls && "?");
-
- /* memoed definition */
- if (xbcap(curdefs) > blk->id && xbcap(curdefs[blk->id]) > var && curdefs[blk->id][var])
- return mkref(RTMP, curdefs[blk->id][var]);
-
- xbgrowz(&curdefs, blk->id + 1);
- if (blk->id > livelastblk) {
- ++npendingphi;
- val = insertphi(blk, cls);
- xbgrowz(&pendingphis, blk->id + 1);
- vpush(&pendingphis[blk->id], ((struct pendingphi) { var, val.i }));
- } else if (blk->npred == 1) {
- val = readvar(defined, cls, var, blkpred(blk, 0));
- } else {
- val = insertphi(blk, cls);
- fillphi(defined, val, cls, var, blk);
- }
- xbgrowz(&curdefs[blk->id], var + 1);
- assert(val.i > 0);
- curdefs[blk->id][var] = val.i;
- return val;
-}
-
-static void
-liveuse(struct bitset *defined, struct instr *ins, union ref *r, struct block *blk)
-{
- int var;
- if (r->t == RADDR) {
- liveuse(defined, ins, &addrtab.p[r->i].base, blk);
- liveuse(defined, ins, &addrtab.p[r->i].index, blk);
- return;
- } else if (r->t != RTMP) return;
- var = r->i;
- if (bstest(defined, var)) return;
-
- *r = readvar(defined, insrescls(instrtab[r->i]), var, blk);
-}
-
-/* regalloc() assumes every use of a temporary is visited before its definition
- * so this pass fixes cases where that would not apply by introducing phi functions */
-static void
-fixlive(struct function *fn)
-{
- extern int ninstr;
- struct block *blk = fn->entry;
- struct bitset definedbuf[4] = {0};
- struct bitset *defined = definedbuf;
-
- if (BSSIZE(ninstr) >= countof(definedbuf))
- defined = xcalloc(sizeof *defined * BSSIZE(ninstr));
- npendingphi = 0;
-
- do {
- for (int i = 0; i < blk->phi.n; ++i) {
- int var = blk->phi.p[i];
- bsset(defined, var);
- }
-
- for (int i = 0; i < blk->ins.n; ++i) {
- int var = blk->ins.p[i];
- struct instr *ins = &instrtab[var];
- if (ins->l.t) liveuse(defined, ins, &ins->l, blk);
- if (ins->r.t) liveuse(defined, ins, &ins->r, blk);
- bsset(defined, var);
- }
- } while ((blk = blk->lnext) != fn->entry);
-
- do {
- vec_of(struct pendingphi) *pphi;
-
- if (!npendingphi) break;
- if (xbcap(pendingphis) <= blk->id) break;
-
- pphi = (void *)&pendingphis[blk->id];
- npendingphi -= pphi->n;
- for (int i = 0; i < pphi->n; ++i) {
- fillphi(defined, mkref(RTMP, pphi->p[i].phi), instrtab[pphi->p[i].phi].cls, pphi->p[i].var, blk);
- }
- vfree(pphi);
- } while ((blk = blk->lnext) != fn->entry);
-
- if (ccopt.dbg.l) {
- bfmt(ccopt.dbgout, "<< After liveness fixup >>\n");
- irdump(fn);
- }
- if (defined != definedbuf) free(defined);
-}
-
-static regset gpregset, fpregset;
-
-#define isfpr(reg) in_range((reg), mctarg->fpr0, mctarg->fpr0 + mctarg->nfpr - 1)
-#define isgpr(reg) in_range((reg), mctarg->gpr0, mctarg->gpr0 + mctarg->nfpr - 1)
-
-/* an allocated physical register or stack slot */
-enum { ADEAD, AREG, ASTACK };
-union alloc { struct { ushort t : 2, a : 14; }; ushort bits; };
-#define afree() ((union alloc) { .t=ADEAD })
-#define areg(r) ((union alloc) { .t=AREG, .a=(r) })
-#define astack(s) ((union alloc) { .t=ASTACK, .a=(s) })
-
-enum { MAXSPILL = 512 };
-
-/* half-closed instr range [from, to) */
-struct range { ushort from, to; };
-#define mkrange(f,t) ((struct range){(f), (t)})
-
-/* a temporary's lifetime interval */
-struct interval {
- struct interval *next; /* for linked list of active,inactive,handled sets in linear scan */
- union alloc alloc;
- schar rhint : 7; /* register hint */
- bool fpr : 1; /* needs float register? */
- uint cost; /* spilling cost estimate */
-
- /* sorted ranges array */
- ushort nrange;
- union {
- struct range _rinl[2];
- struct range *_rdyn;
- };
-};
-
-struct rega {
- struct function *fn;
- struct arena **arena;
-
- int intercount; /* number of actual intervals */
- int ninter; /* size of inter */
- struct interval *inter; /* map of tmp -> interval */
- struct fixinterval {
- struct fixinterval *next;
- regset rs;
- struct range range;
- } *fixed; /* linked list of fixed intervals, always sorted */
-
- struct bitset freestk[BSSIZE(MAXSPILL)]; /* free stack slots */
- int maxstk, /* highest stack slot used */
- stktop;
-};
-
-#define stkslotref(fn, off) \
- (mkaddr((struct addr){.base = mkref(RREG, mctarg->bpr), .disp = -(fn)->stksiz - 8 - (off)}))
-
-/* Parallel moves algorithm from QBE: https://c9x.me/git/qbe.git/tree/rega.c?id=e493a7f23352f51acc0a1e12284ab19d7894488a#n201 */
-
-enum { PMTOMOVE, PMMOVING, PMDONE };
-struct pmstate {
- struct function *fn;
- int npmove;
- struct pmove {
- uchar k; /* enum irclass */
- uchar stat; /* PMTOMOVE|MOVING|DONE */
- union alloc dst, src;
- } pmove[MAXREGS];
-};
-
-static void
-pmadd(struct pmstate *pms, enum irclass k, union alloc dst, union alloc src)
-{
- if (!memcmp(&dst, &src, sizeof dst)) return;
- assert(pms->npmove < MAXREGS);
- pms->pmove[pms->npmove++] = (struct pmove) { k, PMTOMOVE, dst, src };
-}
-
-#define mkmove(k, rd, rs) mkinstr(Omove, k, mkref(RREG, rd), mkref(RREG, rs))
-static void
-emitmove(struct function *fn, enum irclass k, union alloc dst, union alloc src, struct block *blk, int curi)
-{
- struct instr mv = {.keep = 1};
- int reg;
- if (dst.t == AREG && src.t == AREG) {
- insertinstr(blk, curi, mkmove(k, dst.a, src.a));
- return;
- }
- if (src.t == ASTACK) {
- switch (mv.cls = k) {
- default: assert(0);
- case KI32: mv.op = Oloads32; break;
- case KI64: mv.op = Oloadi64; break;
- case KPTR: mv.op = targ_64bit ? Oloadi64 : Oloads32; break;
- case KF32: mv.op = Oloadf32; break;
- case KF64: mv.op = Oloadf64; break;
- }
- if (dst.t == AREG)
- reg = dst.a;
- else
- reg = kisint(k) ? mctarg->gprscratch : mctarg->fprscratch;
- mv.reg = reg+1;
- mv.l = stkslotref(fn, src.a*8);
- insertinstr(blk, curi++, mv);
- } else reg = src.a;
- if (dst.t == ASTACK) {
- mv = mkinstr(cls2store[k], 0, stkslotref(fn, dst.a*8), mkref(RREG, reg));
- insertinstr(blk, curi, mv);
- }
-}
-
-static int
-pmrec(struct pmstate *pms, int i, struct block *blk, int curi, enum irclass *k)
-{
- struct pmove *pm = &pms->pmove[i];
- if (pm->dst.bits == pm->src.bits) {
- pm->stat = PMDONE;
- return -1;
- }
-
- /* widen when necessary */
- assert(kisint(pm->k) == kisint(*k));
- if (cls2siz[pm->k] > cls2siz[*k])
- *k = pm->k;
-
- int j, c;
- for (j = 0; j < pms->npmove; ++j) {
- if (pms->pmove[j].dst.bits == pm->src.bits)
- break;
- }
- if (j == pms->npmove) goto Done;
- switch (pms->pmove[j].stat) {
- default: assert(0);
- case PMMOVING:
- c = j;
- Swap:
- if (pm->src.t == AREG && pm->dst.t == AREG) {
- insertinstr(blk, curi,
- mkinstr(Oswap, *k, mkref(RREG, pm->dst.a), mkref(RREG, pm->src.a), .keep = 1));
- } else if (pm->src.t != pm->dst.t) {
- union alloc reg, stk, regtmp;
- if (pm->src.t == AREG)
- reg = pm->src, stk = pm->dst;
- else
- stk = pm->src, reg = pm->dst;
- assert(reg.t == AREG && stk.t == ASTACK);
- regtmp = areg(kisint(*k) ? mctarg->gprscratch : mctarg->fprscratch);
- emitmove(pms->fn, *k, regtmp, stk, blk, curi++);
- insertinstr(blk, curi++,
- mkinstr(Oswap, *k, mkref(RREG, reg.a), mkref(RREG, regtmp.a), .keep = 1));
- emitmove(pms->fn, *k, stk, regtmp, blk, curi++);
- } else {
- /* FIXME using scratch gpr and fpr for this is hackish */
- assert(pm->src.t == ASTACK && pm->dst.t == ASTACK);
- int r1 = mctarg->gprscratch, r2 = mctarg->fprscratch;
- enum irclass k1 = siz2intcls[cls2siz[*k]], k2 = KF32 + (cls2siz[*k] == 8);
- emitmove(pms->fn, k1, areg(r1), pm->src, blk, curi++);
- emitmove(pms->fn, k2, areg(r2), pm->dst, blk, curi++);
- emitmove(pms->fn, k1, pm->dst, areg(r1), blk, curi++);
- emitmove(pms->fn, k2, pm->src, areg(r2), blk, curi++);
- }
- break;
- case PMTOMOVE:
- pm->stat = PMMOVING;
- c = pmrec(pms, j, blk, curi, k);
- if (c == i) {
- c = -1;
- break;
- } else if (c != -1) {
- goto Swap;
- }
- /* fallthru */
- case PMDONE:
- Done:
- c = -1;
- emitmove(pms->fn, *k, pm->dst, pm->src, blk, curi);
- break;
- }
-
- pm->stat = PMDONE;
- return c;
-}
-
-static void
-emitpm(struct pmstate *pms, struct block *blk)
-{
- int curi = blk->ins.n;
- for (int i = 0; i < pms->npmove; ++i) {
- if (pms->pmove[i].stat == PMTOMOVE) {
- pmrec(pms, i, blk, curi, &(enum irclass) { pms->pmove[i].k });
- }
- }
-}
-
-/* remove phis by inserting parallel moves */
-static void
-lowerphis(struct rega *ra, struct block *blk, struct block *suc)
-{
- int predno;
- struct block *n = NULL;
-
- if (!blk->npred && blk != ra->fn->entry) {
- assert(!blk->phi.n);
- blk->ins.n = 0;
- return;
- }
- if (!blk->s2) n = blk;
-
- for (predno = 0; predno < suc->npred; ++predno)
- if (blkpred(suc, predno) == blk)
- break;
- assert(predno < suc->npred);
-
- struct pmstate pms;
- pms.fn = ra->fn;
- pms.npmove = 0;
- /* ensure phi args go to the same slot as phi with parallel copies */
- for (int i = 0; i < suc->phi.n; ++i) {
- struct instr *phi = &instrtab[suc->phi.p[i]];
- union ref *arg = &phitab.p[phi->l.i][predno];
- union alloc from, to;
-
- if (arg->t == RREG) continue;
- assert(arg->t == RTMP);
- DBG("resolve phi @%d, @%d, %%%d <- %%%d\n", blk->id, suc->id, phi - instrtab, arg->i);
- if (instrtab[arg->i].reg) {
- from = areg(instrtab[arg->i].reg - 1);
- DBG(" it had R%d\n", from.a);
- } else {
- from = ra->inter[arg->i].alloc;
- assert(from.t != ADEAD);
- DBG(" found %c%d\n", " RS"[from.t], from.a);
- if (from.t == AREG)
- instrtab[arg->i].reg = from.a+1;
- }
- if (phi->reg) {
- to = areg(phi->reg - 1);
- DBG(" phi had R%d\n", to.a);
- } else {
- to = ra->inter[phi - instrtab].alloc;
- if (to.t == ADEAD) {
- DBG(" skip dead phi\n");
- continue;
- }
- DBG(" found phi %c%d\n", " RS"[to.t], to.a);
- if (to.t == AREG)
- phi->reg = to.a+1;
- }
- DBG(" > phi move %c%d -> %c%d\n", " RS"[from.t], from.a, " RS"[to.t], to.a);
- if (!n) n = insertblk(ra->fn, blk, suc);
- pmadd(&pms, phi->cls, to, from);
- }
- if (n) emitpm(&pms, n);
-}
-
-/* generate copies for phi operands to transform into conventional-SSA */
-static void
-fixcssa(struct function *fn)
-{
- struct block *blk = fn->entry;
- do {
- if (!blk->phi.n) continue;
- for (int p = 0; p < blk->npred; ++p) {
- struct block *n, *pred = blkpred(blk, p);
- if (!pred->s2) {
- /* pred only has 1 successor (blk), so insert move directly in it */
- n = pred;
- } else {
- n = insertblk(fn, pred, blk);
- assert(n->jmp.t == Jb && n->s1 == blk);
- }
- for (int i = 0; i < blk->phi.n; ++i) {
- int phi = blk->phi.p[i];
- union ref *args = phitab.p[instrtab[phi].l.i];
- args[p] = insertinstr(n, n->ins.n, mkinstr(Ocopy, instrtab[phi].cls, args[p]));
- }
- }
- } while ((blk = blk->lnext) != fn->entry);
-
- fn->prop &= ~FNBLKID;
-}
-
-static inline bool
-rangeoverlap(struct range a, struct range b)
-{
- return a.from < b.to && b.from < a.to;
-}
-
-static void
-pushrange(struct interval *it, struct range r)
-{
- if (it->nrange < 2) it->_rinl[it->nrange++] = r;
- else if (it->nrange > 2) xbpush(&it->_rdyn, &it->nrange, r);
- else {
- struct range *d = NULL;
- xbgrow(&d, 4);
- memcpy(d, it->_rinl, 2*sizeof *d);
- d[it->nrange++] = r;
- it->_rdyn = d;
- }
-}
-#define itrange(it, i) ((it)->nrange <= 2 ? (it)->_rinl : (it)->_rdyn)[i]
-
-static inline int
-intervalbeg(struct interval *it)
-{
- assert(it->nrange);
- return itrange(it, 0).from;
-}
-
-static inline int
-intervalend(struct interval *it)
-{
- assert(it->nrange);
- return itrange(it, it->nrange-1).to;
-}
-
-static bool
-intersoverlap(struct interval *a, struct interval *b)
-{
- for (int i = 0, j = 0; i < a->nrange && j < b->nrange; ) {
- struct range r1 = itrange(a, i), r2 = itrange(b, j);
- if (rangeoverlap(r1, r2)) return 1;
- if (r1.to <= r2.from) ++i;
- else ++j;
- }
- return 0;
-}
-
-static inline void
-incrcost(struct interval *it, struct block *blk)
-{
- /* treat each loop as executing instr 8 times */
- it->cost += 1 << (blk->loop * 3);
-}
-
-static bool
-intervaldef(struct rega *ra, int t, struct block *blk, int pos, int reghint)
-{
- struct interval *it = &ra->inter[t];
- if (it->nrange) {
- ushort *beg = &itrange(it, 0).from;
- assert(*beg <= pos);
- incrcost(it, blk);
- *beg = pos;
- return 1;
- }
- return 0;
-}
-
-static void
-addrange(struct rega *ra, int t, struct range new, int reghint)
-{
- struct interval *it = &ra->inter[t];
- struct range *fst;
- int n;
-
- if (!it->nrange) {
- ++ra->intercount;
- it->rhint = reghint;
- it->fpr = kisflt(insrescls(instrtab[t]));
- pushrange(it, new);
- return;
- }
-
- fst = &itrange(it, 0);
- /* fully covered by first range? */
- if (fst->from <= new.from && fst->to >= new.to) return;
- /* overlaps with first range ? */
- if (fst->from <= new.to && new.to < fst->to) {
- fst->from = new.from;
- } else {
- /* put new range at the start */
- pushrange(it, new);
- memmove(&itrange(it, 1), &itrange(it, 0), sizeof(struct range) * (it->nrange - 1));
- itrange(it, 0) = new;
- }
-
- /* new range might cover existing ranges (loop header lives),
- * check and succesively merge */
- fst = &itrange(it, 0);
- n = 0;
- for (int i = 1; i < it->nrange; ++i) {
- struct range other = itrange(it, i);
- if (fst->to >= other.from) {
- fst->to = fst->to > other.to ? fst->to : other.to;
- ++n;
- } else break;
- }
-
- if (n > 0) {
- for (int i = 1; i + n < it->nrange; ++i)
- itrange(it, i) = itrange(it, i+n);
- if (it->nrange > 2 && it->nrange - n <= 2) {
- struct range *dyn = it->_rdyn;
- memcpy(it->_rinl, dyn, (it->nrange - n) * sizeof *dyn);
- xbfree(dyn);
- }
- it->nrange -= n;
- }
-}
-
-static void
-usereg(struct rega *ra, int reg, struct block *blk, int pos)
-{
- struct fixinterval *fxit;
- if (rstest(mctarg->rglob, reg)) return; /* regalloc never allocates globally live regs, so don't need intervals for those */
- for (struct fixinterval *prev = NULL, *fxit = ra->fixed; fxit; prev = fxit, fxit = fxit->next) {
- if (fxit->range.from > pos) break;
- if (fxit->rs == BIT(reg) && fxit->range.from <= pos && pos < fxit->range.to) {
- /* contained by existing interval */
- fxit->range.from = blk->inumstart;
- /* insert at head */
- //DBG(">>>extend REG %s range %d-%d\n", mctarg->rnames[reg], fxit->range.from, fxit->range.to);
- if (prev) {
- prev->next = fxit->next;
- fxit->next = ra->fixed;
- ra->fixed = fxit;
- }
- return;
- }
- }
- fxit = alloc(ra->arena, sizeof *fxit, 0);
- fxit->next = ra->fixed;
- fxit->range = (struct range) {blk->inumstart, pos};
- fxit->rs = BIT(reg);
- ra->fixed = fxit;
-}
-
-static bool
-defreg(struct rega *ra, int reg, int pos) {
- if (rstest(mctarg->rglob, reg)) return 1;
- for (struct fixinterval *prev = NULL, *fxit = ra->fixed; fxit; prev = fxit, fxit = fxit->next) {
- if (fxit->rs == BIT(reg)) {
- if (fxit->range.from <= pos) {
- fxit->range.from = pos;
- struct fixinterval **at = &ra->fixed;
- if ((*at)->range.from > pos) {
- /* keep sorted */
- //DBG("moved %s\n", mctarg->rnames[reg]);
- if (prev) prev->next = fxit->next;
- while ((*at)->range.from < pos) at = &(*at)->next;
- fxit->next = *at;
- *at = fxit;
- }
- //DBG(">>>def REG %s range %d-%d\n", mctarg->rnames[reg], fxit->range.from, fxit->range.to);
- return 1;
- }
- break;
- }
- }
- return 0;
-}
-
-/* lifetime interval construction */
-static void
-buildintervals(struct rega *ra)
-{
- extern int ninstr;
- struct block *blk, *last;
- struct bitset **livein = alloc(ra->arena, ra->fn->nblk * sizeof *livein, 0);
- size_t bssize = BSSIZE(ninstr);
- struct loops { /* list of loops */
- struct loops *next;
- struct block *hdr, *end;
- } *loops = NULL;
- for (int i = 0; i < ra->fn->nblk; ++i)
- livein[i] = allocz(ra->arena, bssize * sizeof *livein[i], 0);
- ra->inter = allocz(ra->arena, ninstr * sizeof *ra->inter, 0);
- ra->ninter = ninstr;
-
- uint n = numberinstrs(ra->fn);
- assert((ushort)n == n && "too many instrs for struct range");
- /* visit blocks in reverse, to build lifetime intervals */
- blk = last = ra->fn->entry->lprev;
- do {
- struct bitset *live = livein[blk->id];
- /* live = union of successor.liveIn for each successor of b */
- if (blk->s1) bsunion(live, livein[blk->s1->id], bssize);
- if (blk->s2) bsunion(live, livein[blk->s2->id], bssize);
-
- /* for each phi function phi of successors of b do
- * live.add(phi.inputOf(b))
- */
- for (struct block *suc = blk->s1; suc; suc = blk->s2) {
- int predno;
- for (predno = 0; blkpred(suc, predno) != blk; ++predno) ;
- for (int i = 0; i < suc->phi.n; ++i) {
- struct instr *phi = &instrtab[suc->phi.p[i]];
- union ref *arg = &phitab.p[phi->l.i][predno];
- assert(arg->t == RTMP);
- bsset(live, arg->i);
- incrcost(&ra->inter[arg->i], blk);
- }
- if (suc == blk->s2) break;
- }
-
- /* for each opd in live do
- * intervals[opd].addRange(b.from, b.to)
- */
- for (uint i = 0; bsiter(&i, live, bssize); ++i) {
- addrange(ra, i, mkrange(blk->inumstart, blk->inumstart + blk->ins.n + 2), -1);
- }
-
- /* for each operation op of b in reverse order do */
- struct instr *ins = NULL;
- union ref queue[8] = { blk->jmp.arg[0], blk->jmp.arg[1] };
- goto Branchopd;
- for (int curi, pos ; curi >= 0; --curi) {
- int out = blk->ins.p[curi], reghint;
- ins = &instrtab[out];
- pos = blk->inumstart + 1 + curi;
- /* for each output operand opd of op do
- * intervals[opd].setFrom(op.id)
- * live.remove(opd)
- */
- reghint = ins && ins->op == Ocopy && ins->l.t == RREG ? ins->l.i : -1;
- if (!intervaldef(ra, out, blk, pos, reghint)) {
- if (insrescls(*ins) && ins->op != Omove && !ins->keep && !(ins->op == Ocopy && ins->l.t == RREG)) {
- /* dead */
- *ins = mkinstr(Onop,0,);
- }
- }
- bsclr(live, out);
-
- /* gather fixed intervals */
- if (ins->op == Omove) {
- assert(ins->l.t == RREG);
- if (ins->l.bits == ins->r.bits) {/* special case `move Rx,Rx`: clobber reg, not a real use */
- usereg(ra, ins->l.i, blk, pos);
- assert(defreg(ra, ins->l.i, pos));
- } else if (!defreg(ra, ins->l.i, pos)) {
- if (ins->keep) { /* clobber here */
- usereg(ra, ins->l.i, blk, pos);
- assert(defreg(ra, ins->l.i, pos));
- } else {
- /* dead register use. for example if
- * move RCX, %1
- * %2 = shl 1, RCX
- * and %2 is dead, the move to RCX can be killed */
- *ins = mkinstr(Onop,0,);
- }
- } else {
- rsset(&ra->fn->regusage, ins->l.i);
- }
- if (ins->l.bits == ins->r.bits)
- continue;
- } else if (ins->op == Ocall) {
- struct call *call = &calltab.p[ins->r.i];
- regset rclob = (gpregset | fpregset) &~ (mctarg->rglob | mctarg->rcallee);
- ra->fn->isleaf = 0;
-
- for (int i = 0; i < 2; ++i) {
- if (call->abiret[i].ty.bits) {
- int reg = call->abiret[i].reg;
- rsclr(&rclob, reg);
- defreg(ra, reg, pos);
- }
- }
- if (rclob) {
- struct fixinterval *fxit = alloc(ra->arena, sizeof *fxit, 0);
- fxit->next = ra->fixed;
- fxit->range = mkrange(pos, pos);
- fxit->rs = rclob;
- ra->fixed = fxit;
- }
- for (int j = call->narg - 1; j >= 0; --j) {
- struct abiarg abi = call->abiarg[j];
- if (!abi.isstk) {
- usereg(ra, abi.reg, blk, pos);
- }
- }
- }
-
- /* for each input operand opd of op do
- * intervals[opd].addRange(b.from, op.id)
- * live.add(opd)
- */
- reghint = (ins && ins->op == Omove && ins->l.t == RREG) ? ins->l.i : -1;
- queue[0] = ins->r, queue[1] = ins->l;
- if (0) {
- Branchopd:
- reghint = -1;
- curi = blk->ins.n;
- pos = blk->inumstart + blk->ins.n + 1;
- }
- for (int nqueue = ins && ins->op == Omove ? 1 : 2; nqueue > 0;) {
- union ref r = queue[--nqueue];
-
- /* do not allocate a reg for a cmp op used as branch argument, since it's a pseudo op */
- if (curi == blk->ins.n && blk->jmp.t == Jb && r.t == RTMP && instrtab[r.i].keep)
- continue;
-
- if (r.t == RTMP) {
- assert(instrtab[r.i].op != Onop);
- incrcost(&ra->inter[r.i], blk);
- addrange(ra, r.i, mkrange(blk->inumstart, pos), reghint);
- bsset(live, r.i);
- } else if (r.t == RREG) {
- usereg(ra, r.i, blk, pos);
- } else if (r.t == RADDR) {
- reghint = -1;
- queue[nqueue++] = addrtab.p[r.i].base;
- queue[nqueue++] = addrtab.p[r.i].index;
- }
- }
- }
-
- /* for each phi function phi of b do
- * live.remove(phi.output)
- */
- for (int i = 0; i < blk->phi.n; ++i) {
- int phi = blk->phi.p[i];
- bsclr(live, phi);
- for (int i = 0; i < blk->npred; ++i)
- incrcost(&ra->inter[phi], blkpred(blk, i));
- }
-
- /* if b is loop header then
- * loopEnd = last block of the loop starting at b
- * for each opd in live do
- * intervals[opd].addRange(b.from, loopEnd.to)
- */
- struct block *loopend = NULL;
- for (int i = 0; i < blk->npred; ++i) {
- struct block *pred = blkpred(blk, i);
- if (pred->id > blk->id)
- loopend = loopend && loopend->id > pred->id ? loopend : pred;
- }
- if (loopend) {
- if (loops) DBG("@lp @%d\n", blk->id);
- for (struct loops *l = loops; l; l = l->next) {
- /* a nested loop might end later than loopend, which lengthens this outer loop. */
- /* XXX is this correct? more loop analysis might be required? */
- if (l->hdr->id > loopend->id) break;
- DBG(" check <@%d-@%d>\n", l->hdr->id, l->end->id);
- if (l->hdr->id > blk->id && l->hdr->id < loopend->id && l->end->id > loopend->id)
- loopend = l->end;
- }
- DBG("loop header @%d (to @%d)\n", blk->id, loopend->id);
- /* append to loop list */
- loops = alloccopy(ra->arena, &(struct loops){loops, blk, loopend}, sizeof *loops, 0);
- for (uint opd = 0; bsiter(&opd, live, bssize); ++opd) {
- // DBG(" i have live %%%d\n", opd);
- addrange(ra, opd, mkrange(blk->inumstart, loopend->inumstart + loopend->ins.n+1), -1);
- }
- }
- } while ((blk = blk->lprev) != last);
-
- if (ccopt.dbg.r) {
- for (int var = 0; var < ninstr; ++var) {
- struct interval *it = &ra->inter[var];
- if (!it->nrange) continue;
- DBG("lifetime of %%%d: ", var);
- for (int i = 0; i < it->nrange; ++i) {
- struct range r = itrange(it, i);
- DBG("[%d,%d)%s", r.from, r.to, i < it->nrange-1 ? ", " : "");
- }
- DBG(" spill cost: %d\n", it->cost);
- }
- for (struct fixinterval *fx = ra->fixed; fx; fx = fx->next) {
- DBG("fixed {");
- for (int r = 0, f=1; rsiter(&r, fx->rs); ++r, f=0)
- DBG(&" %s"[f], mctarg->rnames[r]);
- DBG("}: [%d,%d)\n", fx->range.from, fx->range.to);
- }
- }
-}
-
-static bool
-itcontainspos(struct interval *it, int pos)
-{
- for (int i = 0; i < it->nrange; ++i) {
- struct range r = itrange(it, i);
- if (r.from > pos) return 0;
- if (pos < r.to) return 1;
- }
- return 0;
-}
-
-/* quicksort */
-static void
-sortintervals(struct interval **xs, int lo, int hi)
-{
- assert(lo >= 0 && hi >= 0);
- while (lo < hi) {
- /* partition */
- int i = lo - 1, p = hi + 1,
- pivot = intervalbeg(xs[lo]);
- for (;;) {
- struct interval *tmp;
- do ++i; while (intervalbeg(xs[i]) < pivot);
- do --p; while (intervalbeg(xs[p]) > pivot);
- if (i >= p) break;
- /* swap */
- tmp = xs[i];
- xs[i] = xs[p];
- xs[p] = tmp;
- }
- /* recur */
- if (p + 1 >= hi) {
- hi = p;
- } else {
- if (lo < p)
- sortintervals(xs, lo, p);
- lo = p + 1;
- }
- }
-}
-
-static union alloc
-allocstk(struct rega *ra)
-{
- uint s = 0;
- if (bsiter(&s, ra->freestk, BSSIZE(MAXSPILL))) {
- bsclr(ra->freestk, s);
- if (ra->stktop < s) ra->stktop = s+1;
- } else {
- s = ra->stktop++;
- }
- if (ra->maxstk < s+1) ra->maxstk = s+1;
- return astack(s);
-}
-
-static void
-freestk(struct rega *ra, int slot)
-{
- DBG("FREE stk %d\n",slot);
- if (slot < MAXSPILL)
- bsset(ra->freestk, slot);
- else if (slot == ra->stktop - 1)
- --ra->stktop;
-}
-
-#define interval2temp(it) (int)(it - ra->inter)
-
-static void
-linearscan(struct rega *ra)
-{
- if (!ra->intercount) return;
-
- /* sort intervals */
- struct interval **unhandled = alloc(ra->arena, sizeof *unhandled * ra->intercount, 0);
- int nunhandled = 0;
- for (int i = 0; i < ra->ninter; ++i) {
- if (!ra->inter[i].nrange) continue;
- unhandled[nunhandled++] = &ra->inter[i];
- }
- assert(nunhandled == ra->intercount);
- sortintervals(unhandled, 0, nunhandled-1);
-
- regset freeregs = (gpregset | fpregset) &~ (mctarg->rglob | (1ull<<mctarg->gprscratch) | (1ull<<mctarg->fprscratch));
- memset(ra->freestk, 0xFF, sizeof ra->freestk);
-
- /* LINEAR SCAN */
- struct interval *actives[2] = {0}, /* gpr set and fpr set */
- *inactives[2] = {0},
- *spilled = NULL, **spilled_tail = &spilled;
- for (struct interval **pcurrent = unhandled; nunhandled > 0; ++pcurrent, --nunhandled) {
- struct interval *current = *pcurrent;
- int pos = intervalbeg(current);
-
- struct interval **active = &actives[current->fpr], **inactive = &inactives[current->fpr],
- **lnk, *it, *next;
- /* Expire old intervals */
- /* check for intervals in active that are handled or inactive */
- for (lnk = active, it = *lnk; (next = it?it->next:0), it; it = next) {
- assert(it->alloc.t == AREG);
- /* ends before position? */
- if (intervalend(it) <= pos) {
- /* move from active to handled */
- *lnk = next;
- //DBG(" unblock %s %X\n", mctarg->rnames[it->alloc.a], ra->free);
- rsset(&freeregs, it->alloc.a);
- } else if (!itcontainspos(it, pos)) { /* it does not cover position? */
- /* move from active to inactive */
- *lnk = next;
- it->next = *inactive;
- *inactive = it;
- rsset(&freeregs, it->alloc.a);
- DBG(" >> %%%zd unblock %s\n", interval2temp(it), mctarg->rnames[it->alloc.a]);
- } else lnk = &it->next;
- }
- /* check for intervals in inactive that are handled or active */
- for (lnk = inactive, it = *lnk; (next = it?it->next:0), it; it = next) {
- assert(it->alloc.t == AREG);
- /* ends before position? */
- if (intervalend(it) <= pos) {
- /* move from inactive to handled */
- *lnk = next;
- } else if (itcontainspos(it, pos)) { /* it covers position? */
- /* move from inactive to active */
- *lnk = next;
- it->next = *active;
- *active = it;
- assert(it->alloc.t == AREG);
- assert(rstest(freeregs, it->alloc.a));
- rsclr(&freeregs, it->alloc.a);
- DBG(" << %%%zd reblock %s\n", interval2temp(it), mctarg->rnames[it->alloc.a]);
- } else lnk = &it->next;
- }
-
- /** find a register for current **/
-
- int this = interval2temp(current);
- regset avail = freeregs & (current->fpr ? fpregset : gpregset),
- fixexcl = 0, excl = 0;
- struct instr *ins = &instrtab[this];
- int reg = 0;
-
- /* exclude regs from overlapping fixed intervals */
- int end = intervalend(current);
- for (struct fixinterval *last = NULL, *fxit = ra->fixed; fxit;
- last = fxit, fxit = fxit->next) {
- if (last) assert(last->range.from <= fxit->range.from && "unsorted fixintervals");
- if (fxit->range.to <= pos) {
- ra->fixed = fxit->next;
- continue;
- } else if (fxit->range.from >= end) {
- break;
- }
-
- for (int i = 0; i < current->nrange; ++i) {
- if (rangeoverlap(fxit->range, itrange(current, i))) {
- fixexcl |= fxit->rs;
- }
- }
- }
- /* exclude regs from overlapping inactive intervals */
- for (struct interval *it = *inactive; it; it = it->next) {
- if (it->alloc.t == AREG && intersoverlap(it, current)) {
- rsset(&excl, it->alloc.a);
- }
- }
- /* for 2-address instrs, exclude reg from 2nd arg (unless arg#1 == arg#2) */
- if (ins->inplace && opnarg[ins->op] == 2) {
- int xreg;
- if (ins->r.t == RREG) rsset(&excl, ins->r.i);
- else if (ins->r.t == RTMP && (xreg = instrtab[ins->r.i].reg)) {
- if (ins->r.bits != ins->l.bits)
- rsset(&fixexcl, xreg-1);
- }
- }
- excl |= fixexcl;
- avail &= ~excl;
-
- if (!avail) { /* no regs left, must spill */
- struct interval **ptospill = NULL, *tospill = current;
- /* heuristic: look for longest-lived active interval with lower spill cost */
- int curend = intervalend(current);
- for (lnk = active, it = *lnk; (next = it ? it->next : 0), it; it = next) {
- int end = intervalend(it);
- if (it->cost < tospill->cost && end > curend && !rstest(fixexcl, it->alloc.a)) {
- ptospill = lnk;
- tospill = it;
- reg = tospill->alloc.a;
- }
- lnk = &it->next;
- }
-
- /* insert in spilled, keep sorted */
- if (ptospill) {
- *ptospill = tospill->next; /* remove from active */
- int from = intervalbeg(tospill);
- lnk = &spilled;
- /* XXX potentially slow linear search */
- while (*lnk && intervalbeg(*lnk) < from)
- lnk = &(*lnk)->next;
- tospill->next = *lnk;
- *lnk = tospill;
- } else { /* tospill == current, so we can just append and keep it sorted */
- *spilled_tail = tospill;
- tospill->next = NULL;
- }
- if (!tospill->next) /* update spilled list tail */
- spilled_tail = &tospill->next;
-
- assert(spilled != NULL);
- if (tospill == current) {
- DBG("spilled %%%d\n", this);
- continue;
- } else {
- instrtab[interval2temp(tospill)].reg = 0;
- DBG("%%%d takes %s from %%%d (spilled)\n", this, mctarg->rnames[reg],
- interval2temp(tospill));
- goto GotReg;
- }
- }
-
- /* have free regs, try to use hint */
- if (current->rhint >= 0)
- DBG("have hint %s for %%%zd\n",
- mctarg->rnames[current->rhint], interval2temp(current));
- if (current->rhint >= 0 && rstest(avail, current->rhint)) {
- DBG(" (used hint)\n");
- reg = current->rhint;
- goto GotReg;
- } else {
- /* for two-address instructions, try to use the reg of left arg */
- if (ins->op != Ophi && (opnarg[ins->op] == 1 || (opnarg[ins->op] == 2 && ins->inplace))) {
- DBG(" %%%d try %d,%d\n", this, ins->l.t,ins->l.i);
- if (ins->l.t == RREG && rstest(avail, reg = ins->l.i))
- goto GotReg;
- if (ins->l.t == RTMP)
- if ((reg = instrtab[ins->l.i].reg-1) >= 0)
- if (rstest(avail, reg))
- goto GotReg;
- /* for phi, try to use reg of any arg */
- } else if (ins->op == Ophi) {
- union ref *arg = phitab.p[ins->l.i];
- for (int i = 0; i < xbcap(arg); ++i) {
- if (arg->t == RREG && rstest(avail, reg = arg->i)) goto GotReg;
- if (arg->t == RTMP)
- if ((reg = instrtab[arg->i].reg-1) >= 0)
- if (rstest(avail, reg))
- goto GotReg;
- }
- }
-
- /* no hints to use */
- if (avail &~ mctarg->rcallee) /* prefer caller-saved regs */
- avail &=~ mctarg->rcallee;
- /* and pick first available reg */
- reg = lowestsetbit(avail);
- }
- GotReg:
- current->alloc = areg(reg);
- ins->reg = reg + 1;
- DBG("%%%d got %s\n", this, mctarg->rnames[reg]);
- rsclr(&freeregs, reg);
- rsset(&ra->fn->regusage, reg);
-
- /* add current to active */
- current->next = *active;
- *active = current;
- }
-
- if (ccopt.dbg.r) {
- DBG("regusage: ");
- for (int r = 0; r < MAXREGS; ++r) {
- if (rstest(ra->fn->regusage, r)) DBG(" %s", mctarg->rnames[r]);
- }
- DBG("\n");
- }
- /* allocate stack slots for spilled intervals
- * this is like another (simplified) linear scan pass */
- struct interval *active = NULL;
- int prevpos = -1;
- if (spilled) DBG("spilled:\n");
- for (struct interval *current = spilled, *next; current; current = next) {
- int pos = intervalbeg(current);
- DBG(" %%%zd: [%d,%d)\n", interval2temp(current), pos, intervalend(current));
- assert(pos >= prevpos && "unsorted spilled?");
- prevpos = pos;
- /* Expire old intervals */
- struct interval **lnk, *it, *lnext;
- for (lnk = &active, it = *lnk; (lnext = it ? it->next : 0), it; it = lnext) {
- /* ends before position? */
- if (intervalend(it) <= pos) {
- /* move from active to handled */
- *lnk = lnext;
- freestk(ra, it->alloc.a);
- } else lnk = &it->next;
- }
- /* allocate a stack slot for current and move to active */
- current->alloc = allocstk(ra);
- DBG(" got stk%d\n", current->alloc.a);
- next = current->next;
- current->next = active;
- active = current;
- }
-}
-
-static bool
-isstoreimm(union ref r)
-{
- if (r.t == RTMP) return 1; /* register OK */
- if (isintcon(r)) switch (target.arch) {
- case ISxxx: assert(0);
- /* TODO don't hard code this architecture dependent dispatch */
- case ISx86_64: return concls(r) == KI32; /* x86: MOV [addr], imm32 */
- case ISaarch64: return r.i == 0; /* arm doesn't have STR <imm>, but has zero register */
- }
- return 0;
-}
-
-/* replace temps with physical regs, add loads & stores for spilled temps */
-static bool
-devirt(struct rega *ra, struct block *blk)
-{
- bool allnops = 1;
- struct function *fn = ra->fn;
- union alloc spillsave[4] = {0};
- memset(ra->freestk, 0, BSSIZE(MAXSPILL) * sizeof *ra->freestk);
-
- for (int curi = 0; curi < blk->ins.n; ++curi) {
- int temp = blk->ins.p[curi];
- struct instr *ins = &instrtab[temp];
- struct interval *it;
- union alloc *alloc;
- struct addr newaddr;
- union ref *argref[4];
- int curi0;
- int naddr = 0;
- int nargref = 0;
- int nspill = 0;
-
- /** devirtualize operands **/
- for (int i = 0; i < 2; ++i) {
- union ref *r = &i[&ins->l];
- if (r->t == RADDR) {
- struct addr *a = &addrtab.p[r->i];
- ++naddr;
- newaddr = *a;
- argref[nargref++] = &newaddr.base;
- argref[nargref++] = &newaddr.index;
- } else {
- argref[nargref++] = r;
- }
- }
- for (int i = 0; i < nargref; ++i) {
- union ref *r = argref[i];
- int tr;
- if (r->t == RTMP && (it = &ra->inter[r->i])->nrange > 0) {
- alloc = &it->alloc;
- if (alloc->t == ASTACK && ins->op == Omove && kisint(ins->cls) == kisint(instrtab[r->i].cls)) {
- /* move [reg], [stk] -> [reg] = load [stk] */
- assert(r == &ins->r && ins->l.t == RREG);
- ins->reg = ins->l.i+1;
- ins->op = cls2load[instrtab[r->i].cls];
- ins->l = stkslotref(fn, alloc->a*8);
- ins->r = NOREF;
- } else if (alloc->t == ASTACK && ins->op == Ocopy && r == &ins->l && ins->reg && kisint(ins->cls) == kisint(instrtab[r->i].cls)) {
- /* [reg] = copy [stk] -> [reg] = load [stk] */
- ins->op = cls2load[instrtab[r->i].cls];
- ins->l = stkslotref(fn, alloc->a*8);
- } else if (alloc->t == ASTACK) {
- /* ref was spilled, gen load to scratch register and use it */
- struct instr ld = {.cls = insrescls(instrtab[r->i])};
- int reg = kisint(ld.cls) ? mctarg->gprscratch : mctarg->fprscratch;
- bool dosave = 0;
- /* pick scratch register, or any register that doesn't conflict with this instr's srcs/dst */
- if (nspill > 0) {
- regset avail = (kisflt(ld.cls) ? fpregset : gpregset) &~ mctarg->rglob;
- if (ins->reg) rsclr(&avail, ins->reg-1);
- for (int j = 0; j < nargref; ++j) {
- struct interval *it;
- if (argref[j]->t == RREG) rsclr(&avail, argref[j]->i);
- else if (argref[j]->t == RTMP) {
- it = &ra->inter[argref[j]->i];
- if (it->alloc.t == AREG) rsclr(&avail, it->alloc.a);
- }
- }
- assert(avail != 0);
- if (avail &~ (fn->regusage | mctarg->rcallee)) avail &= ~(fn->regusage | mctarg->rcallee);
- reg = lowestsetbit(avail);
- /* if not the designated scratch register, we need to save+restore */
- if (rstest(fn->regusage, reg) || rstest(mctarg->rcallee, reg)) {
- dosave = 1;
- if (!spillsave[nspill-1].t) spillsave[nspill-1] = allocstk(ra);
- emitmove(fn, isgpr(reg) ? KPTR : KF64, spillsave[nspill-1], areg(reg), blk, curi++);
- }
- }
- ld.reg = reg+1;
- ld.op = cls2load[ld.cls];
- ld.l = stkslotref(fn, alloc->a*8);
- insertinstr(blk, curi++, ld);
- *r = mkref(RREG, reg);
- if (nspill > 0 && dosave) {
- emitmove(fn, isgpr(reg) ? KPTR : KF64, areg(reg), spillsave[nspill-1], blk, curi+1);
- }
- ++nspill;
- } else if ((tr = instrtab[r->i].reg)) {
- assert(alloc && alloc->t == AREG && alloc->a == tr-1);
- *r = mkref(RREG, tr-1);
- }
- }
- }
- if (nspill > 1) assert(ins->op != Ocall);
- if (naddr) {
- union ref *r = ins->l.t == RADDR ? &ins->l : &ins->r;
- *r = mkaddr(newaddr);
- }
-
- /* devirtualize destination */
- curi0 = curi;
- alloc = temp < ra->ninter && (it = &ra->inter[temp]) && it->nrange ? &it->alloc : NULL;
- if (alloc && alloc->t == ASTACK) {
- enum irclass cls = insrescls(*ins);
- int store = cls2store[cls];
- /* t was spilled, gen store */
- if (ins->op == Ocopy && (ins->l.t == RREG || isstoreimm(ins->l))) {
- ins->op = store;
- ins->r = ins->l;
- ins->l = stkslotref(fn, alloc->a*8);
- } else {
- bool dosave = 0;
- int reg = kisint(insrescls(*ins)) ? mctarg->gprscratch : mctarg->fprscratch;
- if (nspill > 0) {
- regset avail = (kisflt(cls) ? fpregset : gpregset) &~ mctarg->rglob;
- for (int j = 0; j < nargref; ++j) {
- if (argref[j]->t == RREG) rsclr(&avail, argref[j]->i);
- }
- assert(avail != 0);
- if (avail &~ (fn->regusage | mctarg->rcallee)) avail &= ~(fn->regusage | mctarg->rcallee);
- /* if not the designated scratch register, we need to save+restore */
- reg = lowestsetbit(avail);
- if (rstest(fn->regusage, reg) || rstest(mctarg->rcallee, reg)) {
- dosave = 1;
- if (!spillsave[nspill-1].t) spillsave[nspill-1] = allocstk(ra);
- emitmove(fn, isgpr(reg) ? KPTR : KF64, spillsave[nspill-1], areg(reg), blk, curi++);
- curi0 = curi;
- }
- }
- ins->reg = reg+1;
- insertinstr(blk, ++curi,
- mkinstr(store, 0, stkslotref(fn, alloc->a*8), mkref(RREG, reg)));
- if (nspill > 0 && dosave) {
- emitmove(fn, isgpr(reg) ? KPTR : KF64, areg(reg),
- spillsave[nspill-1], blk, ++curi);
- }
- }
- }
- if (!ins->reg && insrescls(*ins) && ins->op != Omove && !ins->keep && !oisstore(ins->op)) {
- /* dead */
- Nop:
- ins->op = Onop;
- } else if (ins->op == Omove && ins->r.t == RREG && ins->l.i == ins->r.i) {
- /* move r1,r2 / r1=r2 */
- goto Nop;
- } else if (ins->op == Ocopy && ins->l.t == RREG && ins->reg-1 == ins->l.i) {
- /* r1 = copy r2 / r1=r2 */
- goto Nop;
- } else if (ins->op != Onop) {
- allnops = 0;
- }
- if (ins->inplace && ins->l.t == RREG && ins->reg && ins->reg-1 != ins->l.i) {
- /* fixup in-place (two-address) instructions */
- allnops = 0;
- insertinstr(blk, curi0, mkmove(ins->cls, ins->reg-1, ins->l.i));
- ++curi;
- ins->l.i = ins->reg-1;
- }
- if (!ins->reg && in_range(ins->op, Oloads8, Oloadf64)) {
- assert(ins->keep);
- ins->reg = kisint(ins->cls) ? mctarg->gprscratch+1 : mctarg->fprscratch+1;
- }
- }
-
- if (allnops) vfree(&blk->ins);
- return allnops;
-}
-
-static void
-fini(struct rega *ra)
-{
- int id = 0;
- struct function *fn = ra->fn;
- struct block *blk = fn->entry;
-
- do {
- blk->id = id++;
- bool allnops = devirt(ra, blk);
- if (allnops && !blk->s2 && blk->npred > 0) { /* remove no-op blocks */
- bool delet = 1;
- for (int i = 0; i < blk->npred; ++i) {
- struct block *p = blkpred(blk, i);
- if (p == blk || (p->s2 && !blk->s1))
- delet = 0;
- }
- for (int i = 0; i < blk->npred; ++i) {
- struct block *p = blkpred(blk, i);
- if (!p->s2 && !blk->s1) {
- /* simplify:
- *
- * @p:
- * ...
- * b @blk
- * @blk:
- * NOP
- * ret/trap
- */
- assert(p->s1 == blk);
- p->jmp.t = blk->jmp.t;
- p->s1 = NULL;
- } else if (blk->s1 && blk->s1 != blk) {
- /* simplify:
- *
- * @p:
- * ...
- * b %x, @blk, @other
- * @blk:
- * NOP
- * b @next
- */
- struct block *next = blk->s1;
- if (p->s1 == blk) p->s1 = next;
- else if (p->s2 == blk) p->s2 = next;
- else continue;
- for (int i = 0; i < next->npred; ++i) {
- if (blkpred(next, i) == blk) {
- blkpred(next, i) = p;
- goto NextPred;
- }
- }
- addpred(next, p);
- }
- NextPred:;
- }
- if (delet) {
- freeblk(fn, blk);
- --id;
- }
- } else if (allnops) {
- vfree(&blk->ins);
- }
- } while ((blk = blk->lnext) != fn->entry);
-}
-
-void
-regalloc(struct function *fn)
-{
- struct rega ra = {fn, .arena = fn->passarena};
- struct block *blk, *last;
-
- /* setup */
- if (!fpregset || !gpregset) {
- for (int r = 0; r < MAXREGS; ++r) {
- if (isfpr(r))
- rsset(&fpregset, r);
- else if (isgpr(r))
- rsset(&gpregset, r);
- }
- }
- fn->regusage = 0;
- fn->stksiz = alignup(fn->stksiz, 8);
- fn->isleaf = 1;
-
- /* put into reverse post order */
- sortrpo(fn);
-
- /* fix liveness ranges */
- fixlive(fn);
-
- /* transform into CSSA */
- fixcssa(fn);
-
- fillblkids(fn);
- fillloop(fn);
-
- if (ccopt.dbg.r) {
- bfmt(ccopt.dbgout, "<< Before linear scan >>\n");
- irdump(fn);
- }
-
- /* linear scan: build lifetime intervals */
- buildintervals(&ra);
-
- /* linear scan: assign physical registers and stack slots */
- linearscan(&ra);
-
- /* get out of SSA */
- blk = last = fn->entry->lprev;
- do {
- if (blk->id < 0) continue;
- for (int i = 0; i < blk->npred; ++i) {
- lowerphis(&ra, blkpred(blk, i), blk);
- }
- vfree(&blk->phi);
- } while ((blk = blk->lprev) != last);
-
- /* devirtualize & final cleanup */
- fini(&ra);
- fn->stksiz += ra.maxstk*8;
- if (fn->stksiz > 1<<24) error(NULL, "'%s' stack frame too big", fn->name);
-
- for (struct interval *it = ra.inter; ra.intercount > 0; ++it) {
- if (it->nrange > 2) xbfree(it->_rdyn);
- if (it->nrange > 0) --ra.intercount;
- }
-
- if (ccopt.dbg.r) {
- bfmt(ccopt.dbgout, "<< After regalloc >>\n");
- irdump(fn);
- }
-}
-
-/* vim:set ts=3 sw=3 expandtab: */
generated by cgit v1.2.3 (git 2.39.1) at 2026-05-02 04:08:09 +0000