Added DFEdge class

llvm/include/llvm/IR/DFNode.h → llvm/include/llvm/IR/DFGraph.h

-//===-- llvm/IR/DFNode.h - Class to represent a single Dataflow Node --===//
+//===----- llvm/IR/DFGraph.h - Classes to represent a Dataflow Graph ------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
@@ -7,8 +7,9 @@
 //
 //===----------------------------------------------------------------------===//
 //
-// This file contains the declaration of the DFNode class, which represents a
-// single VISC Dataflow Node in LLVM.
+// This file contains the declaration of the DFNode and DFEdge class.
+//
+// DFNode represents a single VISC Dataflow Node in LLVM.
 //
 // A Dataflow Node basically consists of 
 // 1. Pointer to a function describing this dataflow node
@@ -18,10 +19,23 @@
 // 5. List of children Dataflow Nodes (empty if it is a leaf node)
 // 6. List of Dataflow Edges among children
 //
+// DFEdge represents a single VISC Dataflow Edge in LLVM.
+// 
+// A Dataflow Edge basically consists of 
+// 1. Pointer to the dataflow node that is the source of this edge
+// 2. Pointer to the dataflow node that is the destination of this edge
+// 3. Pointer to a function that describes which instances of the source
+//    dataflow node are connected to which instances of the destination
+//    dataflow node via this edge
+// 4. Pointer to a function that describes which input arguments of the
+//    destination dataflow node are connected to which outputs of the source
+//    dataflow node via this edge
+//
+// FIXME : We still need to figure out whether these functions are independent
 //===----------------------------------------------------------------------===//
 
-#ifndef LLVM_IR_DFNODE_H
-#define LLVM_IR_DFNODE_H
+#ifndef LLVM_IR_DFGRAPH_H
+#define LLVM_IR_DFGRAPH_H
 
 #include "llvm/IR/Function.h"
 #include "llvm/Support/Compiler.h"
@@ -29,10 +43,11 @@
 namespace llvm {
 class DFNode : public ilist_node<DFNode> {
 
-public:
+private:
   typedef iplist<DFNode> DFNodeListType;
   typedef iplist<DFEdge> DFEdgeListType;
 
+public:
   // DFNode and DFEdge iterators
   typedef DFNodeListType::iterator iterator;
   typedef DFNodeListType::const_iterator const_iterator;
@@ -55,6 +70,25 @@ public:
 
   }
 };
+
+class DFEdge : public ilist_node<DFEdge> {
+private:
+  // Important things that make up a Dataflow Edge
+  DFNode* SrcDF;                ///< Pointer to source dataflow Node
+  DFNode* DestDF;               ///< Pointer to destination dataflow Node
+  Function* DFMapFuncPointer;   ///< Function that associates the appropriate
+                                ///< instances of source and destination
+                                ///< dataflow nodes
+  Function* ArgMapFuncPointer;  ///< Function that associates the input
+                                ///< arguments of destination with the outputs
+                                ///< of source dataflow node
+
+public:
+  static DFEdge *Create(DFNode* SrcDF, DFNode* DestDF, Function* DFMapFuncPointer, Function* ArgMapFuncPointer) {
+    return new DFEdge(SrcDF, DestDF, DFMapFuncPointer, ArgMapFuncPointer);
+
+  }
+};
 } // End llvm namespace
 
 #endif