Generate more useful error messages for unconnected ports.

Force all non-default ports to provide a name and an
owner in the constructor.

9 files changed, 76 insertions, 43 deletions

diff --git a/src/mem/bridge.cc b/src/mem/bridge.cc
index c09cacc00..25c6e5d19 100644
--- a/src/mem/bridge.cc
+++ b/src/mem/bridge.cc
@@ -47,7 +47,7 @@ Bridge::BridgePort::BridgePort(const std::string &_name,
                                int _delay, int _nack_delay, int _req_limit,
                                int _resp_limit,
                                std::vector<Range<Addr> > filter_ranges)
-    : Port(_name), bridge(_bridge), otherPort(_otherPort),
+    : Port(_name, _bridge), bridge(_bridge), otherPort(_otherPort),
       delay(_delay), nackDelay(_nack_delay), filterRanges(filter_ranges),
       outstandingResponses(0), queuedRequests(0), inRetry(false),
       reqQueueLimit(_req_limit), respQueueLimit(_resp_limit), sendEvent(this)
diff --git a/src/mem/bus.cc b/src/mem/bus.cc
index 3bf1c6cfc..9dd3353fd 100644
--- a/src/mem/bus.cc
+++ b/src/mem/bus.cc
@@ -72,8 +72,8 @@ Bus::getPort(const std::string &if_name, int idx)
     return bp;
 }
 
-void
-Bus::deletePortRefs(Port *p)
+bool
+Bus::deletePort(Port *p)
 {
 
     BusPort *bp =  dynamic_cast<BusPort*>(p);
@@ -81,10 +81,11 @@ Bus::deletePortRefs(Port *p)
         panic("Couldn't convert Port* to BusPort*\n");
     // If this is our one functional port
     if (funcPort == bp)
-        return;
+        return false;
     interfaces.erase(bp->getId());
     clearBusCache();
     delete bp;
+    return true;
 }
 
 /** Get the ranges of anyone other buses that we are connected to. */
diff --git a/src/mem/bus.hh b/src/mem/bus.hh
index 74901d626..7d476bb65 100644
--- a/src/mem/bus.hh
+++ b/src/mem/bus.hh
@@ -364,7 +364,7 @@ class Bus : public MemObject
 
     /** A function used to return the port associated with this bus object. */
     virtual Port *getPort(const std::string &if_name, int idx = -1);
-    virtual void deletePortRefs(Port *p);
+    virtual bool deletePort(Port *p);
 
     virtual void init();
     virtual void startup();
diff --git a/src/mem/cache/cache.hh b/src/mem/cache/cache.hh
index 88c9deb7b..56ae811a3 100644
--- a/src/mem/cache/cache.hh
+++ b/src/mem/cache/cache.hh
@@ -217,7 +217,7 @@ class Cache : public BaseCache
     Cache(const Params *p, TagStore *tags, BasePrefetcher *prefetcher);
 
     virtual Port *getPort(const std::string &if_name, int idx = -1);
-    virtual void deletePortRefs(Port *p);
+    virtual bool deletePort(Port *p);
 
     void regStats();
 
diff --git a/src/mem/cache/cache_impl.hh b/src/mem/cache/cache_impl.hh
index 3b56c0a2e..a3dae7b2a 100644
--- a/src/mem/cache/cache_impl.hh
+++ b/src/mem/cache/cache_impl.hh
@@ -105,13 +105,14 @@ Cache<TagStore>::getPort(const std::string &if_name, int idx)
 }
 
 template<class TagStore>
-void
-Cache<TagStore>::deletePortRefs(Port *p)
+bool
+Cache<TagStore>::deletePort(Port *p)
 {
     if (cpuSidePort == p || memSidePort == p)
         panic("Can only delete functional ports\n");
 
     delete p;
+    return true;
 }
 
 
diff --git a/src/mem/mem_object.cc b/src/mem/mem_object.cc
index ce2a1107e..7d27db763 100644
--- a/src/mem/mem_object.cc
+++ b/src/mem/mem_object.cc
@@ -43,8 +43,8 @@ MemObject::makeParams(const std::string &name)
     return params;
 }
 
-void
-MemObject::deletePortRefs(Port *p)
+bool
+MemObject::deletePort(Port *p)
 {
     panic("This object does not support port deletion\n");
 }
diff --git a/src/mem/mem_object.hh b/src/mem/mem_object.hh
index 33b56dfd4..a91ea5ac4 100644
--- a/src/mem/mem_object.hh
+++ b/src/mem/mem_object.hh
@@ -64,9 +64,13 @@ class MemObject : public SimObject
     /** Additional function to return the Port of a memory object. */
     virtual Port *getPort(const std::string &if_name, int idx = -1) = 0;
 
-    /** Tell object that this port is about to disappear, so it should remove it
-     * from any structures that it's keeping it in. */
-    virtual void deletePortRefs(Port *p) ;
+    /** Tell MemObject that this port is no longer in use, so it
+     * should remove it from any structures that it's keeping it in.
+     * If the port was allocated dynamically for this connection, it
+     * should be deleted here.
+     * @return True if the port was deleted, false if it still exists.
+     */
+    virtual bool deletePort(Port *p);
 };
 
 #endif //__MEM_MEM_OBJECT_HH__
diff --git a/src/mem/port.cc b/src/mem/port.cc
index 0e03194c9..1e6989750 100644
--- a/src/mem/port.cc
+++ b/src/mem/port.cc
@@ -39,17 +39,25 @@
 #include "mem/mem_object.hh"
 #include "mem/port.hh"
 
+/**
+ * Special class for port objects that are used as peers for
+ * unconnected ports.  Assigning instances of this class to newly
+ * allocated ports allows us to guarantee that every port has a peer
+ * object (so there's no need to check for null peer pointers), while
+ * catching uses of unconnected ports.
+ */
 class DefaultPeerPort : public Port
 {
   protected:
     void blowUp()
     {
-        fatal("%s: Unconnected port!", peer->name());
+        Port *peer = getPeer();
+        fatal("unconnected port: %s", peer ? peer->name() : "<unknown>");
     }
 
   public:
-    DefaultPeerPort()
-        : Port("default_port")
+    DefaultPeerPort(Port *_peer)
+        : Port("default_port", NULL, _peer)
     { }
 
     bool recvTiming(PacketPtr)
@@ -88,36 +96,59 @@ class DefaultPeerPort : public Port
     bool isDefaultPort() const { return true; }
 };
 
-DefaultPeerPort defaultPeerPort;
 
-Port::Port()
-    : peer(&defaultPeerPort), owner(NULL)
+Port::Port(const std::string &_name, MemObject *_owner, Port *_peer) :
+    portName(_name),
+    peer(_peer ? _peer : new DefaultPeerPort(this)),
+    owner(_owner)
 {
 }
 
-Port::Port(const std::string &_name, MemObject *_owner)
-    : portName(_name), peer(&defaultPeerPort), owner(_owner)
+Port::~Port()
 {
+    disconnectFromPeer();
 }
 
-Port::~Port()
+void
+Port::disconnectFromPeer()
 {
+    if (peer) {
+        assert(peer->getPeer() == this);
+        peer->disconnect();
+    }
 }
 
 void
-Port::setPeer(Port *port)
+Port::disconnect()
 {
-    DPRINTF(Config, "setting peer to %s\n", port->name());
-
-    peer = port;
+    // This notification should come only from our peer, so we must
+    // have one,
+    assert(peer != NULL);
+    // We must clear 'peer' here, else if owner->deletePort() calls
+    // delete on us then we'll recurse infinitely through the Port
+    // destructor.
+    peer = NULL;
+    // If owner->deletePort() returns true, then we've been deleted,
+    // so don't do anything but get out of here.  If not, reset peer
+    // pointer to a DefaultPeerPort.
+    if (!(owner && owner->deletePort(this)))
+        peer = new DefaultPeerPort(this);
 }
 
 void
-Port::removeConn()
+Port::setPeer(Port *port)
 {
-    if (peer->getOwner())
-        peer->getOwner()->deletePortRefs(peer);
-    peer = NULL;
+    DPRINTF(Config, "setting peer to %s, old peer %s\n",
+            port->name(), peer ? peer->name() : "<null>");
+    
+    // You'd think we'd want to disconnect from the previous peer
+    // here, but it turns out that with some functional ports the old
+    // peer keeps using the connection, and it works because
+    // functional ports are unidirectional.
+    //
+    // disconnectFromPeer();
+
+    peer = port;
 }
 
 void
diff --git a/src/mem/port.hh b/src/mem/port.hh
index 15fda2164..4e0d91e75 100644
--- a/src/mem/port.hh
+++ b/src/mem/port.hh
@@ -87,17 +87,14 @@ class Port
 
   public:
 
-    Port();
-
     /**
      * Constructor.
      *
      * @param _name Port name for DPRINTF output.  Should include name
      * of memory system object to which the port belongs.
      * @param _owner Pointer to the MemObject that owns this port.
-     * Will not necessarily be set.
      */
-    Port(const std::string &_name, MemObject *_owner = NULL);
+    Port(const std::string &_name, MemObject *_owner, Port *_peer = NULL);
 
     /** Return port name (for DPRINTF). */
     const std::string &name() const { return portName; }
@@ -111,24 +108,18 @@ class Port
         RangeChange
     };
 
-    void setName(const std::string &name)
-    { portName = name; }
-
     /** Function to set the pointer for the peer port. */
     virtual void setPeer(Port *port);
 
     /** Function to get the pointer to the peer port. */
     Port *getPeer() { return peer; }
 
-    /** Function to set the owner of this port. */
-    void setOwner(MemObject *_owner) { owner = _owner; }
-
     /** Function to return the owner of this port. */
     MemObject *getOwner() { return owner; }
 
-    /** Inform the peer port to delete itself and notify it's owner about it's
-     * demise. */
-    void removeConn();
+    /** Notify my peer port that I'm disconnecting (by calling its
+     * disconnect() method) so it can clean up. */
+    void disconnectFromPeer();
 
     virtual bool isDefaultPort() const { return false; }
 
@@ -254,6 +245,11 @@ class Port
     /** Internal helper function for read/writeBlob().
      */
     void blobHelper(Addr addr, uint8_t *p, int size, MemCmd cmd);
+
+    /** Receive notification that my peer is disconnecting and clean
+     * up (potentially deleting myself in the process). Should be
+     * called only from peer's disconnectFromPeer(). */
+    void disconnect();
 };
 
 /** A simple functional port that is only meant for one way communication to