#include "all.h" voidgetalias(Alias *a, Ref r, Fn *fn){	Con *c; 	switch (rtype(r)) {	default:		die("unreachable");	case RTmp:		*a = fn->tmp[r.val].alias;		if (astack(a->type))			a->type = a->slot->type;		assert(a->type != ABot);		break;	case RCon:		c = &fn->con[r.val];		if (c->type == CAddr) {			a->type = ASym;			a->u.sym = c->sym;		} else			a->type = ACon;		a->offset = c->bits.i;		a->slot = 0;		break;	}} intalias(Ref p, int op, int sp, Ref q, int sq, int *delta, Fn *fn){	Alias ap, aq;	int ovlap; 	getalias(&ap, p, fn);	getalias(&aq, q, fn);	ap.offset += op;	/* when delta is meaningful (ovlap == 1),	 * we do not overflow int because sp and	 * sq are bounded by 2^28 */	*delta = ap.offset - aq.offset;	ovlap = ap.offset < aq.offset + sq && aq.offset < ap.offset + sp; 	if (astack(ap.type) && astack(aq.type)) {		/* if both are offsets of the same		 * stack slot, they alias iif they		 * overlap */		if (ap.base == aq.base && ovlap)			return MustAlias;		return NoAlias;	} 	if (ap.type == ASym && aq.type == ASym) {		/* they conservatively alias if the		 * symbols are different, or they		 * alias for sure if they overlap */		if (!symeq(ap.u.sym, aq.u.sym))			return MayAlias;		if (ovlap)			return MustAlias;		return NoAlias;	} 	if ((ap.type == ACon && aq.type == ACon)	|| (ap.type == aq.type && ap.base == aq.base)) {		assert(ap.type == ACon || ap.type == AUnk);		/* if they have the same base, we		 * can rely on the offsets only */		if (ovlap)			return MustAlias;		return NoAlias;	} 	/* if one of the two is unknown	 * there may be aliasing unless	 * the other is provably local */	if (ap.type == AUnk && aq.type != ALoc)		return MayAlias;	if (aq.type == AUnk && ap.type != ALoc)		return MayAlias; 	return NoAlias;} intescapes(Ref r, Fn *fn){	Alias *a; 	if (rtype(r) != RTmp)		return 1;	a = &fn->tmp[r.val].alias;	return !astack(a->type) || a->slot->type == AEsc;} static voidesc(Ref r, Fn *fn){	Alias *a; 	assert(rtype(r) <= RType);	if (rtype(r) == RTmp) {		a = &fn->tmp[r.val].alias;		if (astack(a->type))			a->slot->type = AEsc;	}} static voidstore(Ref r, int sz, Fn *fn){	Alias *a;	int64_t off;	bits m; 	if (rtype(r) == RTmp) {		a = &fn->tmp[r.val].alias;		if (a->slot) {			assert(astack(a->type));			off = a->offset;			if (sz >= NBit			|| (off < 0 || off >= NBit))				m = -1;			else				m = (BIT(sz) - 1) << off;			a->slot->u.loc.m |= m;		}	}} voidfillalias(Fn *fn){	uint n, m;	int t, sz;	int64_t x;	Blk *b;	Phi *p;	Ins *i;	Con *c;	Alias *a, a0, a1; 	for (t=0; t<fn->ntmp; t++)		fn->tmp[t].alias.type = ABot;	for (n=0; n<fn->nblk; ++n) {		b = fn->rpo[n];		for (p=b->phi; p; p=p->link) {			for (m=0; m<p->narg; m++)				esc(p->arg[m], fn);			assert(rtype(p->to) == RTmp);			a = &fn->tmp[p->to.val].alias;			assert(a->type == ABot);			a->type = AUnk;			a->base = p->to.val;			a->offset = 0;			a->slot = 0;		}		for (i=b->ins; i<&b->ins[b->nins]; ++i) {			a = 0;			if (!req(i->to, R)) {				assert(rtype(i->to) == RTmp);				a = &fn->tmp[i->to.val].alias;				assert(a->type == ABot);				if (Oalloc <= i->op && i->op <= Oalloc1) {					a->type = ALoc;					a->slot = a;					a->u.loc.sz = -1;					if (rtype(i->arg[0]) == RCon) {						c = &fn->con[i->arg[0].val];						x = c->bits.i;						if (c->type == CBits)						if (0 <= x && x <= NBit)							a->u.loc.sz = x;					}				} else {					a->type = AUnk;					a->slot = 0;				}				a->base = i->to.val;				a->offset = 0;			}			if (i->op == Ocopy) {				assert(a);				getalias(a, i->arg[0], fn);			}			if (i->op == Oadd) {				getalias(&a0, i->arg[0], fn);				getalias(&a1, i->arg[1], fn);				if (a0.type == ACon) {					*a = a1;					a->offset += a0.offset;				}				else if (a1.type == ACon) {					*a = a0;					a->offset += a1.offset;				}			}			if (req(i->to, R) || a->type == AUnk)			if (i->op != Oblit0) {				if (!isload(i->op))					esc(i->arg[0], fn);				if (!isstore(i->op))				if (i->op != Oargc)					esc(i->arg[1], fn);			}			if (i->op == Oblit0) {				++i;				assert(i->op == Oblit1);				assert(rtype(i->arg[0]) == RInt);				sz = abs(rsval(i->arg[0]));				store((i-1)->arg[1], sz, fn);			}			if (isstore(i->op))				store(i->arg[1], storesz(i), fn);		}		if (b->jmp.type != Jretc)			esc(b->jmp.arg, fn);	}}