Add new file Support/DataFlow.h.

It allows Use-Def and Def-Use relations to be treated as graphs.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@49088 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Support/DataFlow.h

@@ -0,0 +1,104 @@
+//===-- llvm/Support/DataFlow.h - dataflow as graphs ------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines specializations of GraphTraits that allows Use-Def and 
+// Def-Use relations to be treated as proper graphs for generic algorithms.
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_SUPPORT_DATAFLOW_H
+#define LLVM_SUPPORT_DATAFLOW_H
+
+#include "llvm/User.h"
+#include "llvm/Value.h"
+#include "llvm/ADT/GraphTraits.h"
+
+namespace llvm {
+
+//===----------------------------------------------------------------------===//
+// Provide specializations of GraphTraits to be able to treat def-use/use-def 
+// chains as graphs
+
+template <> struct GraphTraits<const User*> {
+  typedef const Value NodeType;
+  typedef Value::use_const_iterator ChildIteratorType;
+
+  static NodeType *getEntryNode(const User *G) {
+    return G;
+  }
+
+  static inline ChildIteratorType child_begin(NodeType *N) {
+    return N->use_begin();
+  }
+
+  static inline ChildIteratorType child_end(NodeType *N) {
+    return N->use_end();
+  }
+};
+
+template <> struct GraphTraits<User*> {
+  typedef Value NodeType;
+  typedef Value::use_iterator ChildIteratorType;
+
+  static NodeType *getEntryNode(User *G) {
+    return G;
+  }
+
+  static inline ChildIteratorType child_begin(NodeType *N) {
+    return N->use_begin();
+  }
+
+  static inline ChildIteratorType child_end(NodeType *N) {
+    return N->use_end();
+  }
+};
+
+template <> struct GraphTraits<Inverse<const User*> > {
+  typedef const Value NodeType;
+  typedef User::const_op_iterator ChildIteratorType;
+
+  static NodeType *getEntryNode(Inverse<const User*> G) {
+    return G.Graph;
+  }
+
+  static inline ChildIteratorType child_begin(NodeType *N) {
+    if (const User *U = dyn_cast<User>(N))
+      return U->op_begin();
+    return NULL;
+  }
+
+  static inline ChildIteratorType child_end(NodeType *N) {
+    if(const User *U = dyn_cast<User>(N))
+      return U->op_end();
+    return NULL;
+  }
+};
+
+template <> struct GraphTraits<Inverse<User*> > {
+  typedef Value NodeType;
+  typedef User::op_iterator ChildIteratorType;
+
+  static NodeType *getEntryNode(Inverse<User*> G) {
+    return G.Graph;
+  }
+
+  static inline ChildIteratorType child_begin(NodeType *N) {
+    if (User *U = dyn_cast<User>(N))
+      return U->op_begin();
+    return NULL;
+  }
+
+  static inline ChildIteratorType child_end(NodeType *N) {
+    if (User *U = dyn_cast<User>(N))
+      return U->op_end();
+    return NULL;
+  }
+};
+
+}
+#endif