mem: Add predecessor to SenderState base class

This patch adds a predecessor field to the SenderState base class to
make the process of linking them up more uniform, and enable a
traversal of the stack without knowing the specific type of the
subclasses.

There are a number of simplifications done as part of changing the
SenderState, particularly in the RubyTest.

3 files changed, 27 insertions, 39 deletions

diff --git a/src/cpu/testers/rubytest/Check.cc b/src/cpu/testers/rubytest/Check.cc
index a861dbfd8..ae74da67f 100644
--- a/src/cpu/testers/rubytest/Check.cc
+++ b/src/cpu/testers/rubytest/Check.cc
@@ -111,16 +111,13 @@ Check::initiatePrefetch()
 
     // push the subblock onto the sender state.  The sequencer will
     // update the subblock on the return
-    pkt->senderState =
-        new SenderState(m_address, req->getSize(), pkt->senderState);
+    pkt->senderState = new SenderState(m_address, req->getSize());
 
     if (port->sendTimingReq(pkt)) {
         DPRINTF(RubyTest, "successfully initiated prefetch.\n");
     } else {
         // If the packet did not issue, must delete
-        SenderState* senderState =  safe_cast<SenderState*>(pkt->senderState);
-        pkt->senderState = senderState->saved;
-        delete senderState;
+        delete pkt->senderState;
         delete pkt->req;
         delete pkt;
 
@@ -151,8 +148,7 @@ Check::initiateFlush()
 
     // push the subblock onto the sender state.  The sequencer will
     // update the subblock on the return
-    pkt->senderState =
-        new SenderState(m_address, req->getSize(), pkt->senderState);
+    pkt->senderState = new SenderState(m_address, req->getSize());
 
     if (port->sendTimingReq(pkt)) {
         DPRINTF(RubyTest, "initiating Flush - successful\n");
@@ -198,8 +194,7 @@ Check::initiateAction()
 
     // push the subblock onto the sender state.  The sequencer will
     // update the subblock on the return
-    pkt->senderState =
-        new SenderState(writeAddr, req->getSize(), pkt->senderState);
+    pkt->senderState = new SenderState(writeAddr, req->getSize());
 
     if (port->sendTimingReq(pkt)) {
         DPRINTF(RubyTest, "initiating action - successful\n");
@@ -210,9 +205,7 @@ Check::initiateAction()
         // If the packet did not issue, must delete
         // Note: No need to delete the data, the packet destructor
         // will delete it
-        SenderState* senderState = safe_cast<SenderState*>(pkt->senderState);
-        pkt->senderState = senderState->saved;
-        delete senderState;
+        delete pkt->senderState;
         delete pkt->req;
         delete pkt;
 
@@ -250,8 +243,7 @@ Check::initiateCheck()
 
     // push the subblock onto the sender state.  The sequencer will
     // update the subblock on the return
-    pkt->senderState =
-        new SenderState(m_address, req->getSize(), pkt->senderState);
+    pkt->senderState = new SenderState(m_address, req->getSize());
 
     if (port->sendTimingReq(pkt)) {
         DPRINTF(RubyTest, "initiating check - successful\n");
@@ -262,9 +254,7 @@ Check::initiateCheck()
         // If the packet did not issue, must delete
         // Note: No need to delete the data, the packet destructor
         // will delete it
-        SenderState* senderState = safe_cast<SenderState*>(pkt->senderState);
-        pkt->senderState = senderState->saved;
-        delete senderState;
+        delete pkt->senderState;
         delete pkt->req;
         delete pkt;
 
diff --git a/src/cpu/testers/rubytest/RubyTester.cc b/src/cpu/testers/rubytest/RubyTester.cc
index 085647533..68f76f1a6 100644
--- a/src/cpu/testers/rubytest/RubyTester.cc
+++ b/src/cpu/testers/rubytest/RubyTester.cc
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2012 ARM Limited
+ * Copyright (c) 2012-2013 ARM Limited
  * All rights reserved
  *
  * The license below extends only to copyright in the software and shall
@@ -149,17 +149,13 @@ RubyTester::CpuPort::recvTimingResp(PacketPtr pkt)
     // retrieve the subblock and call hitCallback
     RubyTester::SenderState* senderState =
         safe_cast<RubyTester::SenderState*>(pkt->senderState);
-    SubBlock* subblock = senderState->subBlock;
-    assert(subblock != NULL);
+    SubBlock& subblock = senderState->subBlock;
 
-    // pop the sender state from the packet
-    pkt->senderState = senderState->saved;
-
-    tester->hitCallback(id, subblock);
+    tester->hitCallback(id, &subblock);
 
     // Now that the tester has completed, delete the senderState
     // (includes sublock) and the packet, then return
-    delete senderState;
+    delete pkt->senderState;
     delete pkt->req;
     delete pkt;
     return true;
diff --git a/src/cpu/testers/rubytest/RubyTester.hh b/src/cpu/testers/rubytest/RubyTester.hh
index 2fed84e2d..df1bc1fbb 100644
--- a/src/cpu/testers/rubytest/RubyTester.hh
+++ b/src/cpu/testers/rubytest/RubyTester.hh
@@ -1,4 +1,16 @@
 /*
+ * Copyright (c) 2013 ARM Limited
+ * All rights reserved
+ *
+ * The license below extends only to copyright in the software and shall
+ * not be construed as granting a license to any other intellectual
+ * property including but not limited to intellectual property relating
+ * to a hardware implementation of the functionality of the software
+ * licensed hereunder.  You may use the software subject to the license
+ * terms below provided that you ensure that this notice is replicated
+ * unmodified and in its entirety in all distributions of the software,
+ * modified or unmodified, in source code or in binary form.
+ *
  * Copyright (c) 1999-2008 Mark D. Hill and David A. Wood
  * Copyright (c) 2009 Advanced Micro Devices, Inc.
  * All rights reserved.
@@ -69,20 +81,10 @@ class RubyTester : public MemObject
 
     struct SenderState : public Packet::SenderState
     {
-        SubBlock* subBlock;
-        Packet::SenderState *saved;
-
-        SenderState(Address addr, int size,
-                    Packet::SenderState *sender_state = NULL)
-            : saved(sender_state)
-        {
-            subBlock = new SubBlock(addr, size);
-        }
-
-        ~SenderState()
-        {
-            delete subBlock;
-        }
+        SubBlock subBlock;
+
+        SenderState(Address addr, int size) : subBlock(addr, size) {}
+
     };
 
     typedef RubyTesterParams Params;