string nil same as string ""

SVN=124381

src/cmd/6g/cgen.c

@@ -155,6 +155,15 @@ cgen(Node *n, Node *res)
 			regfree(&n1);
 			break;
 		}
+		if(isptrto(nl->type, TMAP)) {
+			regalloc(&n1, types[tptr], res);
+			cgen(nl, &n1);
+			n1.op = OINDREG;
+			n1.type = types[TINT32];
+			gmove(&n1, res);
+			regfree(&n1);
+			break;
+		}
 		fatal("cgen: OLEN: unknown type %lT", nl->type);
 		break;
 

src/cmd/6g/gen.c

@@ -825,11 +825,6 @@ cgen_as(Node *nl, Node *nr, int op)
 
 		case TPTR32:
 		case TPTR64:
-			if(isptrto(nl->type, TSTRING)) {
-				nr->val.ctype = CTSTR;
-				nr->val.sval = &emptystring;
-				break;
-			}
 			nr->val.ctype = CTNIL;
 			nr->val.vval = 0;
 			break;

src/cmd/6g/gsubr.c

@@ -1687,8 +1687,11 @@ stringpool(Node *n)
 	Pool *p;
 	int w;
 
-	if(n->op != OLITERAL || n->val.ctype != CTSTR)
+	if(n->op != OLITERAL || n->val.ctype != CTSTR) {
-		fatal("stringpool: not string");
+		if(n->val.ctype == CTNIL)
+			return;
+		fatal("stringpool: not string %N", n);
+	}
 
 	p = mal(sizeof(*p));
 

src/cmd/gc/walk.c

@@ -239,31 +239,53 @@ loop:
 			goto ret;
 		}
 
-		if(cr != 1) {
-			yyerror("bad shape across assignment");
-			goto ret;
-		}
-
 		switch(r->op) {
 		case OCALLMETH:
 		case OCALLINTER:
 		case OCALL:
+			if(cr == 1) {
+				// a,b,... = fn()
 				walktype(r, Erv);
 				l = ascompatet(n->op, &n->left, &r->type, 0);
 				if(l != N) {
 					*n = *nod(OLIST, r, reorder2(l));
 				}
+				goto ret;
+			}
 			break;
 
 		case OINDEX:
 		case OINDEXPTR:
+			if(cl == 2 && cr == 1) {
+				// a,b = map[] - mapaccess2
 				if(!isptrto(r->left->type, TMAP))
-				goto badt;
+					break;
-			if(cl != 2)
+				l = mapop(n, top);
-				goto badt;
+				if(l == N)
-			*n = *mapop(n, top);
+					break;
+				*n = *l;
+				goto ret;
+			}
 			break;
 		}
+
+		switch(l->op) {
+		case OINDEX:
+		case OINDEXPTR:
+			if(cl == 1 && cr == 2) {
+				// map[] = a,b - mapassign2
+				if(!isptrto(l->left->type, TMAP))
+					break;
+				l = mapop(n, top);
+				if(l == N)
+					break;
+				*n = *l;
+				goto ret;
+			}
+			break;
+		}
+
+		yyerror("bad shape across assignment - cr=%d cl=%d\n", cr, cl);
 		goto ret;
 
 	case OBREAK:
@@ -455,6 +477,8 @@ loop:
 			goto badt;
 		case TSTRING:
 			break;
+		case TMAP:
+			break;
 		}
 		n->type = types[TINT32];
 		goto ret;
@@ -1348,7 +1372,7 @@ mapop(Node *n, int top)
 	Node *r, *a;
 	Type *t;
 	Node *on;
-	int alg1, alg2;
+	int alg1, alg2, cl, cr;
 
 	lno = dynlineno;
 	dynlineno = n->lineno;
@@ -1433,41 +1457,23 @@ mapop(Node *n, int top)
 		r->type = t->type;
 		break;
 
-	access2:
-		// mapaccess2(hmap *map[any-1]any-2, key any-3) (val-4 any, pres bool);
-
-		t = fixmap(n->right->left->type);
-		if(t == T)
-			break;
-
-		a = n->right->right;			// key
-		r = a;
-		a = n->right->left;			// map
-		r = nod(OLIST, a, r);
-
-		on = syslook("mapaccess2", 1);
-
-		argtype(on, t->down);	// any-1
-		argtype(on, t->type);	// any-2
-		argtype(on, t->down);	// any-3
-		argtype(on, t->type);	// any-4
-
-		n->right = nod(OCALL, on, r);
-		walktype(n, Etop);
-		r = n;
-		break;
-
 	case OAS:
-		if(top != Elv) {
+		cl = listcount(n->left);
-			if(top == Etop)
+		cr = listcount(n->right);
+
+		if(cl == 1 && cr == 2)
+			goto assign2;
+		if(cl == 2 && cr == 1)
 			goto access2;
-			goto nottop;
+		if(cl != 1 || cr != 1)
-		}
+			goto shape;
-		if(n->left->op != OINDEX)
-			fatal("mapos: AS left not OINDEX");
 
 		// mapassign1(hmap *map[any-1]any-2, key any-3, val any-4);
 
+//dump("assign1", n);
+		if(n->left->op != OINDEX)
+			goto shape;
+
 		t = fixmap(n->left->left->type);
 		if(t == T)
 			break;
@@ -1490,21 +1496,20 @@ mapop(Node *n, int top)
 		walktype(r, Erv);
 		break;
 
-/* BOTCH get 2nd version attached */
+	assign2:
-		if(top != Elv)
-			goto nottop;
-		if(n->left->op != OINDEX)
-			fatal("mapos: AS left not OINDEX");
-
 		// mapassign2(hmap *map[any]any, key any, val any, pres bool);
 
+//dump("assign2", n);
+		if(n->left->op != OINDEX)
+			goto shape;
+
 		t = fixmap(n->left->left->type);
 		if(t == T)
 			break;
 
-		a = n->right;				// pres
+		a = n->right->right;			// pres
 		r = a;
-		a = n->right;				// val
+		a = n->right->left;			// val
 		r =nod(OLIST, a, r);
 		a = n->left->right;			// key
 		r = nod(OLIST, a, r);
@@ -1522,10 +1527,43 @@ mapop(Node *n, int top)
 		walktype(r, Erv);
 		break;
 
+	access2:
+		// mapaccess2(hmap *map[any-1]any-2, key any-3) (val-4 any, pres bool);
+
+//dump("access2", n);
+		if(n->right->op != OINDEX)
+			goto shape;
+
+		t = fixmap(n->right->left->type);
+		if(t == T)
+			break;
+
+		a = n->right->right;			// key
+		r = a;
+		a = n->right->left;			// map
+		r = nod(OLIST, a, r);
+
+		on = syslook("mapaccess2", 1);
+
+		argtype(on, t->down);	// any-1
+		argtype(on, t->type);	// any-2
+		argtype(on, t->down);	// any-3
+		argtype(on, t->type);	// any-4
+
+		n->right = nod(OCALL, on, r);
+		walktype(n, Etop);
+		r = n;
+		break;
+
 	}
 	dynlineno = lno;
 	return r;
 
+shape:
+	dump("shape", n);
+	fatal("mapop: cl=%d cr=%d, %O", top, n->op);
+	return N;
+
 nottop:
 	dump("bad top", n);
 	fatal("mapop: top=%d %O", top, n->op);

src/runtime/runtime.c

@@ -6,6 +6,9 @@
 
 int32	debug	= 0;
 
+static	int32	empty		= 0;
+static	string	emptystring	= (string)∅
+
 void
 sys_printbool(bool v)
 {
@@ -73,11 +76,12 @@ sys_printpointer(void *p)
 void
 sys_printstring(string v)
 {
+	if(v != nil)
 		sys_write(1, v->str, v->len);
 }
 
 int32
-strlen(int8 *s)
+findnull(int8 *s)
 {
 	int32 l;
 
@@ -89,7 +93,7 @@ strlen(int8 *s)
 void
 prints(int8 *s)
 {
-	sys_write(1, s, strlen(s));
+	sys_write(1, s, findnull(s));
 }
 
 void
@@ -220,6 +224,11 @@ cmpstring(string s1, string s2)
 	uint32 i, l;
 	byte c1, c2;
 
+	if(s1 == nil)
+		s1 = emptystring;
+	if(s2 == nil)
+		s2 = emptystring;
+
 	l = s1->len;
 	if(s2->len < l)
 		l = s2->len;
@@ -250,11 +259,11 @@ sys_catstring(string s1, string s2, string s3)
 {
 	uint32 l;
 
-	if(s1->len == 0) {
+	if(s1 == nil || s1->len == 0) {
 		s3 = s2;
 		goto out;
 	}
-	if(s2->len == 0) {
+	if(s2 == nil || s2->len == 0) {
 		s3 = s1;
 		goto out;
 	}
@@ -317,6 +326,9 @@ sys_slicestring(string si, int32 lindex, int32 hindex, string so)
 	string s, str;
 	int32 l;
 
+	if(si == nil)
+		si = emptystring;
+
 	if(lindex < 0 || lindex > si->len ||
 	   hindex < lindex || hindex > si->len) {
 		sys_printpc(&si);
@@ -334,6 +346,9 @@ sys_slicestring(string si, int32 lindex, int32 hindex, string so)
 void
 sys_indexstring(string s, int32 i, byte b)
 {
+	if(s == nil)
+		s = emptystring;
+
 	if(i < 0 || i >= s->len) {
 		sys_printpc(&s);
 		prints(" ");
@@ -785,6 +800,7 @@ struct	Link
 
 struct	Hmap
 {
+	uint32	len;		// must be first
 	uint32	keysize;
 	uint32	valsize;
 	uint32	hint;
@@ -881,7 +897,7 @@ static void
 stringcopy(uint32 s, string *a, string *b)
 {
 	if(b == nil) {
-		*b = nil;
+		*a = nil;
 		return;
 	}
 	*a = *b;
@@ -932,6 +948,7 @@ sys_newmap(uint32 keysize, uint32 valsize,
 
 	m = mal(sizeof(*m));
 
+	m->len = 0;
 	m->keysize = keysize;
 	m->valsize = valsize;
 	m->keyalg = &algarray[keyalg];
@@ -1053,6 +1070,7 @@ sys_mapassign(Hmap *m, byte *ak, byte *av)
 	l->link = m->link;
 	m->link = l;
 	m->keyalg->copy(m->keysize, l->data, ak);
+	m->len++;
 
 out:
 	m->valalg->copy(m->valsize, l->data+m->valoffset, av);
@@ -1088,7 +1106,6 @@ sys_mapassign2(Hmap *m, ...)
 	Link **ll;
 	byte *ak, *av, *ap;
 
-
 	ak = (byte*)&m + m->ko;
 	av = (byte*)&m + m->vo;
 	ap = (byte*)&m + m->po;
@@ -1104,6 +1121,7 @@ sys_mapassign2(Hmap *m, ...)
 		if(m->keyalg->equal(m->keysize, ak, (*ll)->data)) {
 			m->valalg->copy(m->valsize, (*ll)->data+m->valoffset, nil);
 			(*ll) = (*ll)->link;
+			m->len--;
 			if(debug) {
 				prints("mapdelete (found): map=");
 				sys_printpointer(m);