1 files changed, 34 insertions, 17 deletions

diff --git a/src/rt/rust_upcall.cpp b/src/rt/rust_upcall.cpp
index 42203bec..574cb703 100644
--- a/src/rt/rust_upcall.cpp
+++ b/src/rt/rust_upcall.cpp
@@ -21,11 +21,6 @@
 
 extern "C" CDECL char const *str_buf(rust_task *task, rust_str *s);
 
-inline bool
-requires_message_passing(rust_task *sender, rust_task *receiver) {
-    return sender->dom != receiver->dom;
-}
-
 extern "C" void upcall_grow_task(rust_task *task, size_t n_frame_bytes) {
     LOG_UPCALL_ENTRY(task);
     task->grow(n_frame_bytes);
@@ -96,6 +91,18 @@ extern "C" CDECL void upcall_del_chan(rust_task *task, rust_chan *chan) {
     task->log(rust_log::UPCALL | rust_log::MEM | rust_log::COMM,
               "upcall del_chan(0x%" PRIxPTR ")", (uintptr_t) chan);
     I(dom, !chan->ref_count);
+
+    if (!chan->buffer.is_empty() && chan->is_associated()) {
+        A(dom, !chan->port->is_proxy(),
+          "Channels to remote ports should be flushed automatically.");
+        // A target port may still be reading from this channel.
+        // Block on this channel until it has been completely drained
+        // by the port.
+        task->block(chan);
+        task->yield(2);
+        return;
+    }
+
     delete chan;
 }
 
@@ -105,14 +112,19 @@ extern "C" CDECL void upcall_del_chan(rust_task *task, rust_chan *chan) {
  */
 extern "C" CDECL rust_chan *
 upcall_clone_chan(rust_task *task,
-                  maybe_proxy<rust_task> *spawnee_proxy,
+                  maybe_proxy<rust_task> *target,
                   rust_chan *chan) {
     LOG_UPCALL_ENTRY(task);
-    rust_task *spawnee = spawnee_proxy->delegate();
-    task->log(rust_log::UPCALL | rust_log::MEM | rust_log::COMM,
-              "spawnee: 0x%" PRIxPTR ", chan: 0x%" PRIxPTR,
-              (uintptr_t) spawnee, (uintptr_t) chan);
-    return new (spawnee->dom) rust_chan(spawnee, chan->port);
+    task->log(rust_log::UPCALL | rust_log::COMM,
+              "target: 0x%" PRIxPTR ", chan: 0x%" PRIxPTR,
+              target, chan);
+    rust_task *target_task = target->delegate();
+    maybe_proxy<rust_port> *port = chan->port;
+    if (target->is_proxy()) {
+        port = target_task->dom->get_port_proxy_synchronized(
+                chan->port->as_delegate());
+    }
+    return new (target_task->dom) rust_chan(target_task, port);
 }
 
 extern "C" CDECL void upcall_yield(rust_task *task) {
@@ -145,20 +157,20 @@ upcall_join(rust_task *task, maybe_proxy<rust_task> *target) {
 }
 
 /**
- * Sends an chunk of data along the specified channel.
+ * Buffers a chunk of data in the specified channel.
  *
- * sptr: pointer to a chunk of data to send
+ * sptr: pointer to a chunk of data to buffer
  */
 extern "C" CDECL void
 upcall_send(rust_task *task, rust_chan *chan, void *sptr) {
     LOG_UPCALL_ENTRY(task);
     task->log(rust_log::UPCALL | rust_log::COMM,
               "chan: 0x%" PRIxPTR ", sptr: 0x%" PRIxPTR ", size: %d",
-              (uintptr_t) chan, (uintptr_t) sptr, chan->port->unit_sz);
-
+              (uintptr_t) chan, (uintptr_t) sptr,
+              chan->port->delegate()->unit_sz);
     chan->buffer.enqueue(sptr);
     chan->transmit();
-    task->log(rust_log::COMM, "=== WROTE DATA ===>");
+    task->log(rust_log::COMM, "=== sent data ===>");
 }
 
 extern "C" CDECL void
@@ -174,7 +186,11 @@ upcall_recv(rust_task *task, uintptr_t *dptr, rust_port *port) {
         rust_chan *chan = port->chans[i];
         if (chan->buffer.is_empty() == false) {
             chan->buffer.dequeue(dptr);
-            task->log(rust_log::COMM, "<=== READ DATA ===");
+            if (chan->buffer.is_empty() && chan->task->blocked()) {
+                chan->task->wakeup(chan);
+                delete chan;
+            }
+            task->log(rust_log::COMM, "<=== read data ===");
             return;
         }
     }
@@ -183,6 +199,7 @@ upcall_recv(rust_task *task, uintptr_t *dptr, rust_port *port) {
     // on the port. Remember the rendezvous location so that any sender
     // task can write to it before waking up this task.
 
+    task->log(rust_log::COMM, "<=== waiting for rendezvous data ===");
     task->rendezvous_ptr = dptr;
     task->block(port);
     task->yield(3);