start of coroutine

SVN=126152

src/cmd/gc/go.h

@@ -581,6 +581,7 @@ Node*	nodpanic(long);
 Node*	newcompat(Node*);
 Node*	stringop(Node*, int);
 Node*	mapop(Node*, int);
+Node*	procop(Node*);
 Node*	convas(Node*);
 void	arrayconv(Type*, Node*);
 Node*	colas(Node*, Node*);

src/cmd/gc/go.y

@@ -388,7 +388,8 @@ semi_stmt:
 	}
 |	LGO pexpr '(' oexpr_list ')'
 	{
-		$$ = nod(OPROC, $2, $4);
+		$$ = nod(OCALL, $2, $4);
+		$$ = nod(OPROC, $$, N);
 	}
 |	LPRINT expr_list
 	{

src/cmd/gc/sys.go

@@ -31,10 +31,10 @@ func	envv(int32) string;
 func	frexp(float64) (int32, float64);	// break fp into exp,fract
 func	ldexp(int32, float64) float64;		// make fp from exp,fract
 func	modf(float64) (float64, float64);	// break fp into double.double
-func	isInf(float64, int32) bool;			// test for infinity
-func	isNaN(float64) bool;				// test for not-a-number
-func	Inf(int32) float64;					// return signed Inf
-func	NaN() float64;						// return a NaN
+func	isInf(float64, int32) bool;		// test for infinity
+func	isNaN(float64) bool;			// test for not-a-number
+func	Inf(int32) float64;			// return signed Inf
+func	NaN() float64;				// return a NaN
 
 func	newmap(keysize uint32, valsize uint32,
 		keyalg uint32, valalg uint32,
@@ -44,6 +44,8 @@ func	mapaccess2(hmap *map[any]any, key any) (val any, pres bool);
 func	mapassign1(hmap *map[any]any, key any, val any);
 func	mapassign2(hmap *map[any]any, key any, val any, pres bool);
 
+func	newproc() bool;				// create a new coroutine; true is child
+
 func	readfile(string) (string, bool);	// read file into string; boolean status
 
 func	exit(int32);
@@ -91,6 +93,9 @@ export
 	mapassign1
 	mapassign2
 
+	// threads/coroutines
+	newproc
+
 	// files
 	readfile
 

src/cmd/gc/walk.c

@@ -156,6 +156,12 @@ loop:
 		n = n->nbody;
 		goto loop;
 
+	case OPROC:
+		if(top != Etop)
+			goto nottop;
+		*n = *procop(n);
+		goto ret;
+
 	case OCALLMETH:
 	case OCALLINTER:
 	case OCALL:
@@ -1588,6 +1594,27 @@ nottop:
 	return N;
 }
 
+Node*
+procop(Node *n)
+{
+	Node *r, *on;
+
+	switch(n->op) {
+	default:
+		fatal("mapop: unknown op %E", n->op);
+
+	case OPROC:	// rewrite if(sys.newproc()) (n->left)
+		on = syslook("newproc", 0);
+		r = nod(OIF, N, N);
+		r->ntest = nod(OCALL, on, N);
+		r->nbody = n->left;
+dump("newproc", r);
+		walktype(r, Etop);
+		break;
+	}
+	return r;
+}
+
 void
 diagnamed(Type *t)
 {