slicc: support for multiple message types on the same buffer

This patch allows SLICC protocols to use more than one message type with a
message buffer. For example, you can declare two in ports as such:

  in_port(ResponseQueue_in, ResponseMsg, responseFromDir, rank=3) { ... }
  in_port(tgtResponseQueue_in, TgtResponseMsg, responseFromDir, rank=2) { ... }

1 files changed, 6 insertions, 1 deletions

diff --git a/src/mem/slicc/ast/PeekStatementAST.py b/src/mem/slicc/ast/PeekStatementAST.py
index d267df26e..cecb9aa9f 100644
--- a/src/mem/slicc/ast/PeekStatementAST.py
+++ b/src/mem/slicc/ast/PeekStatementAST.py
@@ -62,7 +62,12 @@ class PeekStatementAST(StatementAST):
     // Declare message
     const $mtid* in_msg_ptr M5_VAR_USED;
     in_msg_ptr = dynamic_cast<const $mtid *>(($qcode).${{self.method}}());
-    assert(in_msg_ptr != NULL); // Check the cast result
+    if (in_msg_ptr == NULL) {
+        // If the cast fails, this is the wrong inport (wrong message type).
+        // Throw an exception, and the caller will decide to either try a
+        // different inport or punt.
+        throw RejectException();
+    }
 ''')
 
         if self.pairs.has_key("block_on"):