runtime: convert closechan/chanlen/chancap to Go

LGTM=bradfitz, rsc
R=golang-codereviews, bradfitz, rsc
CC=golang-codereviews
https://golang.org/cl/135150043

src/pkg/runtime/chan.go

@@ -150,12 +150,7 @@ func chansend(t *chantype, c *hchan, ep unsafe.Pointer, block bool, callerpc uin
 				memmove(unsafe.Pointer(sg.elem), ep, uintptr(c.elemsize))
 			}
 			if sg.releasetime != 0 {
-				// Yes, this is ugly.  On 64-bit sg.releasetime has type
-				// int.  On 32-bit it has type int64.  There's no easy way
-				// to assign to both types in Go.  At some point we'll
-				// write the Go types directly instead of generating them
-				// via the C types.  At that point, this nastiness goes away.
-				*(*int64)(unsafe.Pointer(&sg.releasetime)) = cputicks()
+				sg.releasetime = cputicks()
 			}
 			goready(recvg)
 			return true
@@ -248,7 +243,7 @@ func chansend(t *chantype, c *hchan, ep unsafe.Pointer, block bool, callerpc uin
 		recvg := sg.g
 		unlock(&c.lock)
 		if sg.releasetime != 0 {
-			*(*int64)(unsafe.Pointer(&sg.releasetime)) = cputicks()
+			sg.releasetime = cputicks()
 		}
 		goready(recvg)
 	} else {
@@ -260,6 +255,72 @@ func chansend(t *chantype, c *hchan, ep unsafe.Pointer, block bool, callerpc uin
 	return true
 }
 
+func closechan(c *hchan) {
+	if c == nil {
+		panic("close of nil channel")
+	}
+
+	lock(&c.lock)
+	if c.closed != 0 {
+		unlock(&c.lock)
+		panic("close of closed channel")
+	}
+
+	if raceenabled {
+		callerpc := getcallerpc(unsafe.Pointer(&c))
+		fn := closechan
+		pc := **(**uintptr)(unsafe.Pointer(&fn))
+		racewritepc(unsafe.Pointer(c), callerpc, pc)
+		racerelease(unsafe.Pointer(c))
+	}
+
+	c.closed = 1
+
+	// release all readers
+	for {
+		sg := c.recvq.dequeue()
+		if sg == nil {
+			break
+		}
+		gp := sg.g
+		gp.param = nil
+		if sg.releasetime != 0 {
+			sg.releasetime = cputicks()
+		}
+		goready(gp)
+	}
+
+	// release all writers
+	for {
+		sg := c.sendq.dequeue()
+		if sg == nil {
+			break
+		}
+		gp := sg.g
+		gp.param = nil
+		if sg.releasetime != 0 {
+			sg.releasetime = cputicks()
+		}
+		goready(gp)
+	}
+
+	unlock(&c.lock)
+}
+
+func reflect_chanlen(c *hchan) int {
+	if c == nil {
+		return 0
+	}
+	return int(c.qcount)
+}
+
+func reflect_chancap(c *hchan) int {
+	if c == nil {
+		return 0
+	}
+	return int(c.dataqsiz)
+}
+
 func (q *waitq) enqueue(sgp *sudog) {
 	sgp.next = nil
 	if q.first == nil {

src/pkg/runtime/chan.goc

@@ -1005,81 +1005,6 @@ func reflect·rselect(cases Slice) (chosen int, recvOK bool) {
 	chosen = (intgo)(uintptr)selectgo(&sel);
 }
 
-static void closechan(Hchan *c, void *pc);
-
-#pragma textflag NOSPLIT
-func closechan(c *Hchan) {
-	closechan(c, runtime·getcallerpc(&c));
-}
-
-#pragma textflag NOSPLIT
-func reflect·chanclose(c *Hchan) {
-	closechan(c, runtime·getcallerpc(&c));
-}
-
-static void
-closechan(Hchan *c, void *pc)
-{
-	SudoG *sg;
-	G* gp;
-
-	if(c == nil)
-		runtime·panicstring("close of nil channel");
-
-	runtime·lock(&c->lock);
-	if(c->closed) {
-		runtime·unlock(&c->lock);
-		runtime·panicstring("close of closed channel");
-	}
-
-	if(raceenabled) {
-		runtime·racewritepc(c, pc, runtime·closechan);
-		runtime·racerelease(c);
-	}
-
-	c->closed = true;
-
-	// release all readers
-	for(;;) {
-		sg = dequeue(&c->recvq);
-		if(sg == nil)
-			break;
-		gp = sg->g;
-		gp->param = nil;
-		if(sg->releasetime)
-			sg->releasetime = runtime·cputicks();
-		runtime·ready(gp);
-	}
-
-	// release all writers
-	for(;;) {
-		sg = dequeue(&c->sendq);
-		if(sg == nil)
-			break;
-		gp = sg->g;
-		gp->param = nil;
-		if(sg->releasetime)
-			sg->releasetime = runtime·cputicks();
-		runtime·ready(gp);
-	}
-
-	runtime·unlock(&c->lock);
-}
-
-func reflect·chanlen(c *Hchan) (len int) {
-	if(c == nil)
-		len = 0;
-	else
-		len = c->qcount;
-}
-
-func reflect·chancap(c *Hchan) (cap int) {
-	if(c == nil)
-		cap = 0;
-	else
-		cap = c->dataqsiz;
-}
-
 static SudoG*
 dequeue(WaitQ *q)
 {

src/pkg/runtime/thunk.s

@@ -52,3 +52,12 @@ TEXT bytes·Compare(SB),NOSPLIT,$0-0
 
 TEXT runtime·reflectcall(SB), NOSPLIT, $0-0
 	JMP	reflect·call(SB)
+
+TEXT reflect·chanclose(SB), NOSPLIT, $0-0
+	JMP	runtime·closechan(SB)
+
+TEXT reflect·chanlen(SB), NOSPLIT, $0-0
+	JMP	runtime·reflect_chanlen(SB)
+
+TEXT reflect·chancap(SB), NOSPLIT, $0-0
+	JMP	runtime·reflect_chancap(SB)