--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/include/llvm/XRay/Graph.h	Fri Oct 27 17:07:41 2017 +0900
@@ -0,0 +1,494 @@
+//===-- Graph.h - XRay Graph Class ------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// A Graph Datatype for XRay.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_XRAY_GRAPH_T_H
+#define LLVM_XRAY_GRAPH_T_H
+
+#include <initializer_list>
+#include <stdint.h>
+#include <type_traits>
+#include <utility>
+
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/DenseSet.h"
+#include "llvm/ADT/iterator.h"
+#include "llvm/Support/Error.h"
+
+namespace llvm {
+namespace xray {
+
+/// A Graph object represents a Directed Graph and is used in XRay to compute
+/// and store function call graphs and associated statistical information.
+///
+/// The graph takes in four template parameters, these are:
+///  - VertexAttribute, this is a structure which is stored for each vertex.
+///    Must be DefaultConstructible, CopyConstructible, CopyAssignable and
+///    Destructible.
+///  - EdgeAttribute, this is a structure which is stored for each edge
+///    Must be DefaultConstructible, CopyConstructible, CopyAssignable and
+///    Destructible.
+///  - EdgeAttribute, this is a structure which is stored for each variable
+///  - VI, this is a type over which DenseMapInfo is defined and is the type
+///    used look up strings, available as VertexIdentifier.
+///  - If the built in DenseMapInfo is not defined, provide a specialization
+///    class type here.
+///
+/// Graph is CopyConstructible, CopyAssignable, MoveConstructible and
+/// MoveAssignable but is not EqualityComparible or LessThanComparible.
+///
+/// Usage Example Graph with weighted edges and vertices:
+///   Graph<int, int, int> G;
+///
+///   G[1] = 0;
+///   G[2] = 2;
+///   G[{1,2}] = 1;
+///   G[{2,1}] = -1;
+///   for(const auto &v : G.vertices()){
+///     // Do something with the vertices in the graph;
+///   }
+///   for(const auto &e : G.edges()){
+///     // Do something with the edges in the graph;
+///   }
+///
+/// Usage Example with StrRef keys.
+///   Graph<int, double, StrRef> StrG;
+///    char va[] = "Vertex A";
+///    char vaa[] = "Vertex A";
+///    char vb[] = "Vertex B"; // Vertices are referenced by String Refs.
+///    G[va] = 0;
+///    G[vb] = 1;
+///    G[{va, vb}] = 1.0;
+///    cout() << G[vaa] << " " << G[{vaa, vb}]; //prints "0 1.0".
+///
+template <typename VertexAttribute, typename EdgeAttribute,
+          typename VI = int32_t>
+class Graph {
+public:
+  /// These objects are used to name edges and vertices in the graph.
+  typedef VI VertexIdentifier;
+  typedef std::pair<VI, VI> EdgeIdentifier;
+
+  /// This type is the value_type of all iterators which range over vertices,
+  /// Determined by the Vertices DenseMap
+  using VertexValueType =
+      detail::DenseMapPair<VertexIdentifier, VertexAttribute>;
+
+  /// This type is the value_type of all iterators which range over edges,
+  /// Determined by the Edges DenseMap.
+  using EdgeValueType = detail::DenseMapPair<EdgeIdentifier, EdgeAttribute>;
+
+  using size_type = std::size_t;
+
+private:
+  /// The type used for storing the EdgeAttribute for each edge in the graph
+  using EdgeMapT = DenseMap<EdgeIdentifier, EdgeAttribute>;
+
+  /// The type used for storing the VertexAttribute for each vertex in
+  /// the graph.
+  using VertexMapT = DenseMap<VertexIdentifier, VertexAttribute>;
+
+  /// The type used for storing the edges entering a vertex. Indexed by
+  /// the VertexIdentifier of the start of the edge. Only used to determine
+  /// where the incoming edges are, the EdgeIdentifiers are stored in an
+  /// InnerEdgeMapT.
+  using NeighborSetT = DenseSet<VertexIdentifier>;
+
+  /// The type storing the InnerInvGraphT corresponding to each vertex in
+  /// the graph (When a vertex has an incoming edge incident to it)
+  using NeighborLookupT = DenseMap<VertexIdentifier, NeighborSetT>;
+
+private:
+  /// Stores the map from the start and end vertex of an edge to it's
+  /// EdgeAttribute
+  EdgeMapT Edges;
+
+  /// Stores the map from VertexIdentifier to VertexAttribute
+  VertexMapT Vertices;
+
+  /// Allows fast lookup for the incoming edge set of any given vertex.
+  NeighborLookupT InNeighbors;
+
+  /// Allows fast lookup for the outgoing edge set of any given vertex.
+  NeighborLookupT OutNeighbors;
+
+  /// An Iterator adapter using an InnerInvGraphT::iterator as a base iterator,
+  /// and storing the VertexIdentifier the iterator range comes from. The
+  /// dereference operator is then performed using a pointer to the graph's edge
+  /// set.
+  template <bool IsConst, bool IsOut,
+            typename BaseIt = typename NeighborSetT::const_iterator,
+            typename T = typename std::conditional<IsConst, const EdgeValueType,
+                                                   EdgeValueType>::type>
+  class NeighborEdgeIteratorT
+      : public iterator_adaptor_base<
+            NeighborEdgeIteratorT<IsConst, IsOut>, BaseIt,
+            typename std::iterator_traits<BaseIt>::iterator_category, T> {
+    using InternalEdgeMapT =
+        typename std::conditional<IsConst, const EdgeMapT, EdgeMapT>::type;
+
+    friend class NeighborEdgeIteratorT<false, IsOut, BaseIt, EdgeValueType>;
+    friend class NeighborEdgeIteratorT<true, IsOut, BaseIt,
+                                       const EdgeValueType>;
+
+    InternalEdgeMapT *MP;
+    VertexIdentifier SI;
+
+  public:
+    template <bool IsConstDest,
+              typename = typename std::enable_if<IsConstDest && !IsConst>::type>
+    operator NeighborEdgeIteratorT<IsConstDest, IsOut, BaseIt,
+                                   const EdgeValueType>() const {
+      return NeighborEdgeIteratorT<IsConstDest, IsOut, BaseIt,
+                                   const EdgeValueType>(this->I, MP, SI);
+    }
+
+    NeighborEdgeIteratorT() = default;
+    NeighborEdgeIteratorT(BaseIt _I, InternalEdgeMapT *_MP,
+                          VertexIdentifier _SI)
+        : iterator_adaptor_base<
+              NeighborEdgeIteratorT<IsConst, IsOut>, BaseIt,
+              typename std::iterator_traits<BaseIt>::iterator_category, T>(_I),
+          MP(_MP), SI(_SI) {}
+
+    T &operator*() const {
+      if (!IsOut)
+        return *(MP->find({*(this->I), SI}));
+      else
+        return *(MP->find({SI, *(this->I)}));
+    }
+  };
+
+public:
+  /// A const iterator type for iterating through the set of edges entering a
+  /// vertex.
+  ///
+  /// Has a const EdgeValueType as its value_type
+  using ConstInEdgeIterator = NeighborEdgeIteratorT<true, false>;
+
+  /// An iterator type for iterating through the set of edges leaving a vertex.
+  ///
+  /// Has an EdgeValueType as its value_type
+  using InEdgeIterator = NeighborEdgeIteratorT<false, false>;
+
+  /// A const iterator type for iterating through the set of edges entering a
+  /// vertex.
+  ///
+  /// Has a const EdgeValueType as its value_type
+  using ConstOutEdgeIterator = NeighborEdgeIteratorT<true, true>;
+
+  /// An iterator type for iterating through the set of edges leaving a vertex.
+  ///
+  /// Has an EdgeValueType as its value_type
+  using OutEdgeIterator = NeighborEdgeIteratorT<false, true>;
+
+  /// A class for ranging over the incoming edges incident to a vertex.
+  ///
+  /// Like all views in this class it provides methods to get the beginning and
+  /// past the range iterators for the range, as well as methods to determine
+  /// the number of elements in the range and whether the range is empty.
+  template <bool isConst, bool isOut> class InOutEdgeView {
+  public:
+    using iterator = NeighborEdgeIteratorT<isConst, isOut>;
+    using const_iterator = NeighborEdgeIteratorT<true, isOut>;
+    using GraphT = typename std::conditional<isConst, const Graph, Graph>::type;
+    using InternalEdgeMapT =
+        typename std::conditional<isConst, const EdgeMapT, EdgeMapT>::type;
+
+  private:
+    InternalEdgeMapT &M;
+    const VertexIdentifier A;
+    const NeighborLookupT &NL;
+
+  public:
+    iterator begin() {
+      auto It = NL.find(A);
+      if (It == NL.end())
+        return iterator();
+      return iterator(It->second.begin(), &M, A);
+    }
+
+    const_iterator cbegin() const {
+      auto It = NL.find(A);
+      if (It == NL.end())
+        return const_iterator();
+      return const_iterator(It->second.begin(), &M, A);
+    }
+
+    const_iterator begin() const { return cbegin(); }
+
+    iterator end() {
+      auto It = NL.find(A);
+      if (It == NL.end())
+        return iterator();
+      return iterator(It->second.end(), &M, A);
+    }
+    const_iterator cend() const {
+      auto It = NL.find(A);
+      if (It == NL.end())
+        return const_iterator();
+      return const_iterator(It->second.end(), &M, A);
+    }
+
+    const_iterator end() const { return cend(); }
+
+    size_type size() const {
+      auto I = NL.find(A);
+      if (I == NL.end())
+        return 0;
+      else
+        return I->second.size();
+    }
+
+    bool empty() const { return NL.count(A) == 0; };
+
+    InOutEdgeView(GraphT &G, VertexIdentifier A)
+        : M(G.Edges), A(A), NL(isOut ? G.OutNeighbors : G.InNeighbors) {}
+  };
+
+  /// A const iterator type for iterating through the whole vertex set of the
+  /// graph.
+  ///
+  /// Has a const VertexValueType as its value_type
+  using ConstVertexIterator = typename VertexMapT::const_iterator;
+
+  /// An iterator type for iterating through the whole vertex set of the graph.
+  ///
+  /// Has a VertexValueType as its value_type
+  using VertexIterator = typename VertexMapT::iterator;
+
+  /// A class for ranging over the vertices in the graph.
+  ///
+  /// Like all views in this class it provides methods to get the beginning and
+  /// past the range iterators for the range, as well as methods to determine
+  /// the number of elements in the range and whether the range is empty.
+  template <bool isConst> class VertexView {
+  public:
+    using iterator = typename std::conditional<isConst, ConstVertexIterator,
+                                               VertexIterator>::type;
+    using const_iterator = ConstVertexIterator;
+    using GraphT = typename std::conditional<isConst, const Graph, Graph>::type;
+
+  private:
+    GraphT &G;
+
+  public:
+    iterator begin() { return G.Vertices.begin(); }
+    iterator end() { return G.Vertices.end(); }
+    const_iterator cbegin() const { return G.Vertices.cbegin(); }
+    const_iterator cend() const { return G.Vertices.cend(); }
+    const_iterator begin() const { return G.Vertices.begin(); }
+    const_iterator end() const { return G.Vertices.end(); }
+    size_type size() const { return G.Vertices.size(); }
+    bool empty() const { return G.Vertices.empty(); }
+    VertexView(GraphT &_G) : G(_G) {}
+  };
+
+  /// A const iterator for iterating through the entire edge set of the graph.
+  ///
+  /// Has a const EdgeValueType as its value_type
+  using ConstEdgeIterator = typename EdgeMapT::const_iterator;
+
+  /// An iterator for iterating through the entire edge set of the graph.
+  ///
+  /// Has an EdgeValueType as its value_type
+  using EdgeIterator = typename EdgeMapT::iterator;
+
+  /// A class for ranging over all the edges in the graph.
+  ///
+  /// Like all views in this class it provides methods to get the beginning and
+  /// past the range iterators for the range, as well as methods to determine
+  /// the number of elements in the range and whether the range is empty.
+  template <bool isConst> class EdgeView {
+  public:
+    using iterator = typename std::conditional<isConst, ConstEdgeIterator,
+                                               EdgeIterator>::type;
+    using const_iterator = ConstEdgeIterator;
+    using GraphT = typename std::conditional<isConst, const Graph, Graph>::type;
+
+  private:
+    GraphT &G;
+
+  public:
+    iterator begin() { return G.Edges.begin(); }
+    iterator end() { return G.Edges.end(); }
+    const_iterator cbegin() const { return G.Edges.cbegin(); }
+    const_iterator cend() const { return G.Edges.cend(); }
+    const_iterator begin() const { return G.Edges.begin(); }
+    const_iterator end() const { return G.Edges.end(); }
+    size_type size() const { return G.Edges.size(); }
+    bool empty() const { return G.Edges.empty(); }
+    EdgeView(GraphT &_G) : G(_G) {}
+  };
+
+public:
+  // TODO: implement constructor to enable Graph Initialisation.\
+  // Something like:
+  //   Graph<int, int, int> G(
+  //   {1, 2, 3, 4, 5},
+  //   {{1, 2}, {2, 3}, {3, 4}});
+
+  /// Empty the Graph
+  void clear() {
+    Edges.clear();
+    Vertices.clear();
+    InNeighbors.clear();
+    OutNeighbors.clear();
+  }
+
+  /// Returns a view object allowing iteration over the vertices of the graph.
+  /// also allows access to the size of the vertex set.
+  VertexView<false> vertices() { return VertexView<false>(*this); }
+
+  VertexView<true> vertices() const { return VertexView<true>(*this); }
+
+  /// Returns a view object allowing iteration over the edges of the graph.
+  /// also allows access to the size of the edge set.
+  EdgeView<false> edges() { return EdgeView<false>(*this); }
+
+  EdgeView<true> edges() const { return EdgeView<true>(*this); }
+
+  /// Returns a view object allowing iteration over the edges which start at
+  /// a vertex I.
+  InOutEdgeView<false, true> outEdges(const VertexIdentifier I) {
+    return InOutEdgeView<false, true>(*this, I);
+  }
+
+  InOutEdgeView<true, true> outEdges(const VertexIdentifier I) const {
+    return InOutEdgeView<true, true>(*this, I);
+  }
+
+  /// Returns a view object allowing iteration over the edges which point to
+  /// a vertex I.
+  InOutEdgeView<false, false> inEdges(const VertexIdentifier I) {
+    return InOutEdgeView<false, false>(*this, I);
+  }
+
+  InOutEdgeView<true, false> inEdges(const VertexIdentifier I) const {
+    return InOutEdgeView<true, false>(*this, I);
+  }
+
+  /// Looks up the vertex with identifier I, if it does not exist it default
+  /// constructs it.
+  VertexAttribute &operator[](const VertexIdentifier &I) {
+    return Vertices.FindAndConstruct(I).second;
+  }
+
+  /// Looks up the edge with identifier I, if it does not exist it default
+  /// constructs it, if it's endpoints do not exist it also default constructs
+  /// them.
+  EdgeAttribute &operator[](const EdgeIdentifier &I) {
+    auto &P = Edges.FindAndConstruct(I);
+    Vertices.FindAndConstruct(I.first);
+    Vertices.FindAndConstruct(I.second);
+    InNeighbors[I.second].insert(I.first);
+    OutNeighbors[I.first].insert(I.second);
+    return P.second;
+  }
+
+  /// Looks up a vertex with Identifier I, or an error if it does not exist.
+  Expected<VertexAttribute &> at(const VertexIdentifier &I) {
+    auto It = Vertices.find(I);
+    if (It == Vertices.end())
+      return make_error<StringError>(
+          "Vertex Identifier Does Not Exist",
+          std::make_error_code(std::errc::invalid_argument));
+    return It->second;
+  }
+
+  Expected<const VertexAttribute &> at(const VertexIdentifier &I) const {
+    auto It = Vertices.find(I);
+    if (It == Vertices.end())
+      return make_error<StringError>(
+          "Vertex Identifier Does Not Exist",
+          std::make_error_code(std::errc::invalid_argument));
+    return It->second;
+  }
+
+  /// Looks up an edge with Identifier I, or an error if it does not exist.
+  Expected<EdgeAttribute &> at(const EdgeIdentifier &I) {
+    auto It = Edges.find(I);
+    if (It == Edges.end())
+      return make_error<StringError>(
+          "Edge Identifier Does Not Exist",
+          std::make_error_code(std::errc::invalid_argument));
+    return It->second;
+  }
+
+  Expected<const EdgeAttribute &> at(const EdgeIdentifier &I) const {
+    auto It = Edges.find(I);
+    if (It == Edges.end())
+      return make_error<StringError>(
+          "Edge Identifier Does Not Exist",
+          std::make_error_code(std::errc::invalid_argument));
+    return It->second;
+  }
+
+  /// Looks for a vertex with identifier I, returns 1 if one exists, and
+  /// 0 otherwise
+  size_type count(const VertexIdentifier &I) const {
+    return Vertices.count(I);
+  }
+
+  /// Looks for an edge with Identifier I, returns 1 if one exists and 0
+  /// otherwise
+  size_type count(const EdgeIdentifier &I) const { return Edges.count(I); }
+
+  /// Inserts a vertex into the graph with Identifier Val.first, and
+  /// Attribute Val.second.
+  std::pair<VertexIterator, bool>
+  insert(const std::pair<VertexIdentifier, VertexAttribute> &Val) {
+    return Vertices.insert(Val);
+  }
+
+  std::pair<VertexIterator, bool>
+  insert(std::pair<VertexIdentifier, VertexAttribute> &&Val) {
+    return Vertices.insert(std::move(Val));
+  }
+
+  /// Inserts an edge into the graph with Identifier Val.first, and
+  /// Attribute Val.second. If the key is already in the map, it returns false
+  /// and doesn't update the value.
+  std::pair<EdgeIterator, bool>
+  insert(const std::pair<EdgeIdentifier, EdgeAttribute> &Val) {
+    const auto &p = Edges.insert(Val);
+    if (p.second) {
+      const auto &EI = Val.first;
+      Vertices.FindAndConstruct(EI.first);
+      Vertices.FindAndConstruct(EI.second);
+      InNeighbors[EI.second].insert(EI.first);
+      OutNeighbors[EI.first].insert(EI.second);
+    };
+
+    return p;
+  }
+
+  /// Inserts an edge into the graph with Identifier Val.first, and
+  /// Attribute Val.second. If the key is already in the map, it returns false
+  /// and doesn't update the value.
+  std::pair<EdgeIterator, bool>
+  insert(std::pair<EdgeIdentifier, EdgeAttribute> &&Val) {
+    auto EI = Val.first;
+    const auto &p = Edges.insert(std::move(Val));
+    if (p.second) {
+      Vertices.FindAndConstruct(EI.first);
+      Vertices.FindAndConstruct(EI.second);
+      InNeighbors[EI.second].insert(EI.first);
+      OutNeighbors[EI.first].insert(EI.second);
+    };
+
+    return p;
+  }
+};
+}
+}
+#endif