src/cmd/5c/swt.c

// Inferno utils/5c/swt.c
// http://code.google.com/p/inferno-os/source/browse/utils/5c/swt.c
//
//	Copyright © 1994-1999 Lucent Technologies Inc.  All rights reserved.
//	Portions Copyright © 1995-1997 C H Forsyth (forsyth@terzarima.net)
//	Portions Copyright © 1997-1999 Vita Nuova Limited
//	Portions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com)
//	Portions Copyright © 2004,2006 Bruce Ellis
//	Portions Copyright © 2005-2007 C H Forsyth (forsyth@terzarima.net)
//	Revisions Copyright © 2000-2007 Lucent Technologies Inc. and others
//	Portions Copyright © 2009 The Go Authors.  All rights reserved.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.

#include "gc.h"

int
swcmp(const void *a1, const void *a2)
{
	C1 *p1, *p2;

	p1 = (C1*)a1;
	p2 = (C1*)a2;
	if(p1->val < p2->val)
		return -1;
	return  p1->val > p2->val;
}

void
doswit(Node *n)
{
	Case *c;
	C1 *q, *iq;
	int32 def, nc, i;
	Node tn;

	def = 0;
	nc = 0;
	for(c = cases; c->link != C; c = c->link) {
		if(c->def) {
			if(def)
				diag(n, "more than one default in switch");
			def = c->label;
			continue;
		}
		nc++;
	}

	iq = alloc(nc*sizeof(C1));
	q = iq;
	for(c = cases; c->link != C; c = c->link) {
		if(c->def)
			continue;
		q->label = c->label;
		q->val = c->val;
		q++;
	}
	qsort(iq, nc, sizeof(C1), swcmp);
	if(debug['W'])
		for(i=0; i<nc; i++)
			print("case %2ld: = %.8lux\n", i, iq[i].val);
	if(def == 0)
		def = breakpc;
	for(i=0; i<nc-1; i++)
		if(iq[i].val == iq[i+1].val)
			diag(n, "duplicate cases in switch %ld", iq[i].val);
	regalloc(&tn, &regnode, Z);
	swit1(iq, nc, def, n, &tn);
	regfree(&tn);
}

void
swit1(C1 *q, int nc, int32 def, Node *n, Node *tn)
{
	C1 *r;
	int i;
	int32 v;
	Prog *sp;

	if(nc >= 3) {
		i = (q+nc-1)->val - (q+0)->val;
		if(i > 0 && i < nc*2)
			goto direct;
	}
	if(nc < 5) {
		for(i=0; i<nc; i++) {
			if(debug['W'])
				print("case = %.8lux\n", q->val);
			gopcode(OEQ, nodconst(q->val), n, Z);
			patch(p, q->label);
			q++;
		}
		gbranch(OGOTO);
		patch(p, def);
		return;
	}

	i = nc / 2;
	r = q+i;
	if(debug['W'])
		print("case > %.8lux\n", r->val);
	gopcode(OGT, nodconst(r->val), n, Z);
	sp = p;
	gopcode(OEQ, nodconst(r->val), n, Z);	/* just gen the B.EQ */
	patch(p, r->label);
	swit1(q, i, def, n, tn);

	if(debug['W'])
		print("case < %.8lux\n", r->val);
	patch(sp, pc);
	swit1(r+1, nc-i-1, def, n, tn);
	return;

direct:
	v = q->val;
	if(v != 0)
		gopcode(OSUB, nodconst(v), Z, n);
	gopcode(OCASE, nodconst((q+nc-1)->val - v), n, Z);
	patch(p, def);
	for(i=0; i<nc; i++) {
		if(debug['W'])
			print("case = %.8lux\n", q->val);
		while(q->val != v) {
			nextpc();
			p->as = ABCASE;
			patch(p, def);
			v++;
		}
		nextpc();
		p->as = ABCASE;
		patch(p, q->label);
		q++;
		v++;
	}
	gbranch(OGOTO);		/* so that regopt() won't be confused */
	patch(p, def);
}

void
cas(void)
{
	Case *c;

	c = alloc(sizeof(*c));
	c->link = cases;
	cases = c;
}

void
bitload(Node *b, Node *n1, Node *n2, Node *n3, Node *nn)
{
	int sh;
	int32 v;
	Node *l;

	/*
	 * n1 gets adjusted/masked value
	 * n2 gets address of cell
	 * n3 gets contents of cell
	 */
	l = b->left;
	if(n2 != Z) {
		regalloc(n1, l, nn);
		reglcgen(n2, l, Z);
		regalloc(n3, l, Z);
		gopcode(OAS, n2, Z, n3);
		gopcode(OAS, n3, Z, n1);
	} else {
		regalloc(n1, l, nn);
		cgen(l, n1, 0);
	}
	if(b->type->shift == 0 && typeu[b->type->etype]) {
		v = ~0 + (1L << b->type->nbits);
		gopcode(OAND, nodconst(v), Z, n1);
	} else {
		sh = 32 - b->type->shift - b->type->nbits;
		if(sh > 0)
			gopcode(OASHL, nodconst(sh), Z, n1);
		sh += b->type->shift;
		if(sh > 0)
			if(typeu[b->type->etype])
				gopcode(OLSHR, nodconst(sh), Z, n1);
			else
				gopcode(OASHR, nodconst(sh), Z, n1);
	}
}

void
bitstore(Node *b, Node *n1, Node *n2, Node *n3, Node *nn)
{
	int32 v;
	Node nod, *l;
	int sh;

	/*
	 * n1 has adjusted/masked value
	 * n2 has address of cell
	 * n3 has contents of cell
	 */
	l = b->left;
	regalloc(&nod, l, Z);
	v = ~0 + (1L << b->type->nbits);
	gopcode(OAND, nodconst(v), Z, n1);
	gopcode(OAS, n1, Z, &nod);
	if(nn != Z)
		gopcode(OAS, n1, Z, nn);
	sh = b->type->shift;
	if(sh > 0)
		gopcode(OASHL, nodconst(sh), Z, &nod);
	v <<= sh;
	gopcode(OAND, nodconst(~v), Z, n3);
	gopcode(OOR, n3, Z, &nod);
	gopcode(OAS, &nod, Z, n2);

	regfree(&nod);
	regfree(n1);
	regfree(n2);
	regfree(n3);
}

int32
outstring(char *s, int32 n)
{
	int32 r;

	if(suppress)
		return nstring;
	r = nstring;
	while(n) {
		string[mnstring] = *s++;
		mnstring++;
		nstring++;
		if(mnstring >= NSNAME) {
			gpseudo(ADATA, symstring, nodconst(0L));
			p->from.offset += nstring - NSNAME;
			p->reg = NSNAME;
			p->to.type = D_SCONST;
			memmove(p->to.sval, string, NSNAME);
			mnstring = 0;
		}
		n--;
	}
	return r;
}

int32
outlstring(ushort *s, int32 n)
{
	char buf[2];
	int c;
	int32 r;

	if(suppress)
		return nstring;
	while(nstring & 1)
		outstring("", 1);
	r = nstring;
	while(n > 0) {
		c = *s++;
		if(align(0, types[TCHAR], Aarg1)) {
			buf[0] = c>>8;
			buf[1] = c;
		} else {
			buf[0] = c;
			buf[1] = c>>8;
		}
		outstring(buf, 2);
		n -= sizeof(ushort);
	}
	return r;
}

int
mulcon(Node *n, Node *nn)
{
	Node *l, *r, nod1, nod2;
	Multab *m;
	int32 v, vs;
	int o;
	char code[sizeof(m->code)+2], *p;

	if(typefd[n->type->etype])
		return 0;
	l = n->left;
	r = n->right;
	if(l->op == OCONST) {
		l = r;
		r = n->left;
	}
	if(r->op != OCONST)
		return 0;
	v = convvtox(r->vconst, n->type->etype);
	if(v != r->vconst) {
		if(debug['M'])
			print("%L multiply conv: %lld\n", n->lineno, r->vconst);
		return 0;
	}
	m = mulcon0(v);
	if(!m) {
		if(debug['M'])
			print("%L multiply table: %lld\n", n->lineno, r->vconst);
		return 0;
	}
	if(debug['M'] && debug['v'])
		print("%L multiply: %ld\n", n->lineno, v);

	memmove(code, m->code, sizeof(m->code));
	code[sizeof(m->code)] = 0;

	p = code;
	if(p[1] == 'i')
		p += 2;
	regalloc(&nod1, n, nn);
	cgen(l, &nod1, 0);
	vs = v;
	regalloc(&nod2, n, Z);

loop:
	switch(*p) {
	case 0:
		regfree(&nod2);
		if(vs < 0) {
			gopcode(OAS, &nod1, Z, &nod1);
			gopcode(OSUB, &nod1, nodconst(0), nn);
		} else 
			gopcode(OAS, &nod1, Z, nn);
		regfree(&nod1);
		return 1;
	case '+':
		o = OADD;
		goto addsub;
	case '-':
		o = OSUB;
	addsub:	/* number is r,n,l */
		v = p[1] - '0';
		r = &nod1;
		if(v&4)
			r = &nod2;
		n = &nod1;
		if(v&2)
			n = &nod2;
		l = &nod1;
		if(v&1)
			l = &nod2;
		gopcode(o, l, n, r);
		break;
	default: /* op is shiftcount, number is r,l */
		v = p[1] - '0';
		r = &nod1;
		if(v&2)
			r = &nod2;
		l = &nod1;
		if(v&1)
			l = &nod2;
		v = *p - 'a';
		if(v < 0 || v >= 32) {
			diag(n, "mulcon unknown op: %c%c", p[0], p[1]);
			break;
		}
		gopcode(OASHL, nodconst(v), l, r);
		break;
	}
	p += 2;
	goto loop;
}

void
nullwarn(Node *l, Node *r)
{
	warn(Z, "result of operation not used");
	if(l != Z)
		cgen(l, Z, 0);
	if(r != Z)
		cgen(r, Z, 0);
}

void
sextern(Sym *s, Node *a, int32 o, int32 w)
{
	int32 e, lw;

	for(e=0; e<w; e+=NSNAME) {
		lw = NSNAME;
		if(w-e < lw)
			lw = w-e;
		gpseudo(ADATA, s, nodconst(0));
		p->from.offset += o+e;
		p->reg = lw;
		p->to.type = D_SCONST;
		memmove(p->to.sval, a->cstring+e, lw);
	}
}

void
gextern(Sym *s, Node *a, int32 o, int32 w)
{

	if(a->op == OCONST && typev[a->type->etype]) {
		if(1 || align(0, types[TCHAR], Aarg1))	/* isbigendian */
			gpseudo(ADATA, s, nod32const(a->vconst>>32));
		else
			gpseudo(ADATA, s, nod32const(a->vconst));
		p->from.offset += o;
		p->reg = 4;
		if(1 || align(0, types[TCHAR], Aarg1))	/* isbigendian */
			gpseudo(ADATA, s, nod32const(a->vconst));
		else
			gpseudo(ADATA, s, nod32const(a->vconst>>32));
		p->from.offset += o + 4;
		p->reg = 4;
		return;
	}
	gpseudo(ADATA, s, a);
	p->from.offset += o;
	p->reg = w;
	if(p->to.type == D_OREG)
		p->to.type = D_CONST;
}

void	zname(Biobuf*, Sym*, int);
char*	zaddr(char*, Adr*, int);
void	zwrite(Biobuf*, Prog*, int, int);
void	outhist(Biobuf*);

void
zwrite(Biobuf *b, Prog *p, int sf, int st)
{
	char bf[100], *bp;

	bf[0] = p->as;
	bf[1] = p->scond;
	bf[2] = p->reg;
	bf[3] = p->lineno;
	bf[4] = p->lineno>>8;
	bf[5] = p->lineno>>16;
	bf[6] = p->lineno>>24;
	bp = zaddr(bf+7, &p->from, sf);
	bp = zaddr(bp, &p->to, st);
	Bwrite(b, bf, bp-bf);
}

void
outcode(void)
{
	struct { Sym *sym; short type; } h[NSYM];
	Prog *p;
	Sym *s;
	int sf, st, t, sym;

	if(debug['S']) {
		for(p = firstp; p != P; p = p->link)
			if(p->as != ADATA && p->as != AGLOBL)
				pc--;
		for(p = firstp; p != P; p = p->link) {
			print("%P\n", p);
			if(p->as != ADATA && p->as != AGLOBL)
				pc++;
		}
	}
	outhist(&outbuf);
	for(sym=0; sym<NSYM; sym++) {
		h[sym].sym = S;
		h[sym].type = 0;
	}
	sym = 1;
	for(p = firstp; p != P; p = p->link) {
	jackpot:
		sf = 0;
		s = p->from.sym;
		while(s != S) {
			sf = s->sym;
			if(sf < 0 || sf >= NSYM)
				sf = 0;
			t = p->from.name;
			if(h[sf].type == t)
			if(h[sf].sym == s)
				break;
			s->sym = sym;
			zname(&outbuf, s, t);
			h[sym].sym = s;
			h[sym].type = t;
			sf = sym;
			sym++;
			if(sym >= NSYM)
				sym = 1;
			break;
		}
		st = 0;
		s = p->to.sym;
		while(s != S) {
			st = s->sym;
			if(st < 0 || st >= NSYM)
				st = 0;
			t = p->to.name;
			if(h[st].type == t)
			if(h[st].sym == s)
				break;
			s->sym = sym;
			zname(&outbuf, s, t);
			h[sym].sym = s;
			h[sym].type = t;
			st = sym;
			sym++;
			if(sym >= NSYM)
				sym = 1;
			if(st == sf)
				goto jackpot;
			break;
		}
		zwrite(&outbuf, p, sf, st);
	}
	firstp = P;
	lastp = P;
}

void
outhist(Biobuf *b)
{
	Hist *h;
	char *p, *q, *op, c;
	Prog pg;
	int n;

	pg = zprog;
	pg.as = AHISTORY;
	c = pathchar();
	for(h = hist; h != H; h = h->link) {
		p = h->name;
		op = 0;
		/* on windows skip drive specifier in pathname */
		if(systemtype(Windows) && p && p[1] == ':'){
			p += 2;
			c = *p;
		}
		if(p && p[0] != c && h->offset == 0 && pathname){
			/* on windows skip drive specifier in pathname */
			if(systemtype(Windows) && pathname[1] == ':') {
				op = p;
				p = pathname+2;
				c = *p;
			} else if(pathname[0] == c){
				op = p;
				p = pathname;
			}
		}
		while(p) {
			q = utfrune(p, c);
			if(q) {
				n = q-p;
				if(n == 0){
					n = 1;	/* leading "/" */
					*p = '/';	/* don't emit "\" on windows */
				}
				q++;
			} else {
				n = strlen(p);
				q = 0;
			}
			if(n) {
				Bputc(b, ANAME);
				Bputc(b, D_FILE);
				Bputc(b, 1);
				Bputc(b, '<');
				Bwrite(b, p, n);
				Bputc(b, 0);
			}
			p = q;
			if(p == 0 && op) {
				p = op;
				op = 0;
			}
		}
		pg.lineno = h->line;
		pg.to.type = zprog.to.type;
		pg.to.offset = h->offset;
		if(h->offset)
			pg.to.type = D_CONST;

		zwrite(b, &pg, 0, 0);
	}
}

void
zname(Biobuf *b, Sym *s, int t)
{
	char *n, bf[7];
	uint32 sig;

	n = s->name;
	if(debug['T'] && t == D_EXTERN && s->sig != SIGDONE && s->type != types[TENUM] && s != symrathole){
		sig = sign(s);
		bf[0] = ASIGNAME;
		bf[1] = sig;
		bf[2] = sig>>8;
		bf[3] = sig>>16;
		bf[4] = sig>>24;
		bf[5] = t;
		bf[6] = s->sym;
		Bwrite(b, bf, 7);
		s->sig = SIGDONE;
	}
	else{
		bf[0] = ANAME;
		bf[1] = t;	/* type */
		bf[2] = s->sym;	/* sym */
		Bwrite(b, bf, 3);
	}
	Bwrite(b, n, strlen(n)+1);
}

char*
zaddr(char *bp, Adr *a, int s)
{
	int32 l;
	Ieee e;

	bp[0] = a->type;
	bp[1] = a->reg;
	bp[2] = s;
	bp[3] = a->name;
	bp += 4;
	switch(a->type) {
	default:
		diag(Z, "unknown type %d in zaddr", a->type);

	case D_NONE:
	case D_REG:
	case D_FREG:
	case D_PSR:
		break;

	case D_OREG:
	case D_CONST:
	case D_BRANCH:
	case D_SHIFT:
		l = a->offset;
		bp[0] = l;
		bp[1] = l>>8;
		bp[2] = l>>16;
		bp[3] = l>>24;
		bp += 4;
		break;

	case D_SCONST:
		memmove(bp, a->sval, NSNAME);
		bp += NSNAME;
		break;

	case D_FCONST:
		ieeedtod(&e, a->dval);
		l = e.l;
		bp[0] = l;
		bp[1] = l>>8;
		bp[2] = l>>16;
		bp[3] = l>>24;
		bp += 4;
		l = e.h;
		bp[0] = l;
		bp[1] = l>>8;
		bp[2] = l>>16;
		bp[3] = l>>24;
		bp += 4;
		break;
	}
	return bp;
}

void
ieeedtod(Ieee *ieee, double native)
{
	double fr, ho, f;
	int exp;

	if(native < 0) {
		ieeedtod(ieee, -native);
		ieee->h |= 0x80000000L;
		return;
	}
	if(native == 0) {
		ieee->l = 0;
		ieee->h = 0;
		return;
	}
	fr = frexp(native, &exp);
	f = 2097152L;		/* shouldnt use fp constants here */
	fr = modf(fr*f, &ho);
	ieee->h = ho;
	ieee->h &= 0xfffffL;
	ieee->h |= (exp+1022L) << 20;
	f = 65536L;
	fr = modf(fr*f, &ho);
	ieee->l = ho;
	ieee->l <<= 16;
	ieee->l |= (int32)(fr*f);
}

int32
align(int32 i, Type *t, int op)
{
	int32 o;
	Type *v;
	int w;

	o = i;
	w = 1;
	switch(op) {
	default:
		diag(Z, "unknown align opcode %d", op);
		break;

	case Asu2:	/* padding at end of a struct */
		w = SZ_LONG;
		if(packflg)
			w = packflg;
		break;

	case Ael1:	/* initial allign of struct element */
		for(v=t; v->etype==TARRAY; v=v->link)
			;
		w = ewidth[v->etype];
		if(w <= 0 || w >= SZ_LONG)
			w = SZ_LONG;
		if(packflg)
			w = packflg;
		break;

	case Ael2:	/* width of a struct element */
		o += t->width;
		break;

	case Aarg0:	/* initial passbyptr argument in arg list */
		if(typesuv[t->etype]) {
			o = align(o, types[TIND], Aarg1);
			o = align(o, types[TIND], Aarg2);
		}
		break;

	case Aarg1:	/* initial allign of parameter */
		w = ewidth[t->etype];
		if(w <= 0 || w >= SZ_LONG) {
			w = SZ_LONG;
			break;
		}
		w = 1;		/* little endian no adjustment */
		break;

	case Aarg2:	/* width of a parameter */
		o += t->width;
		w = SZ_LONG;
		break;

	case Aaut3:	/* total allign of automatic */
		o = align(o, t, Ael2);
		o = align(o, t, Ael1);
		w = SZ_LONG;	/* because of a pun in cc/dcl.c:contig() */
		break;
	}
	o = xround(o, w);
	if(debug['A'])
		print("align %s %ld %T = %ld\n", bnames[op], i, t, o);
	return o;
}

int32
maxround(int32 max, int32 v)
{
	v = xround(v, SZ_LONG);
	if(v > max)
		return v;
	return max;
}