[clang-diff] Move printing of matches and changes to clang-diff

Summary:
This also changes the output order of the changes. Now the matches are
printed in pre-order, intertwined with insertions, updates, and moves.
Deletions are printed afterwards.

Reviewers: arphaman

Subscribers: klimek

Differential Revision: https://reviews.llvm.org/D36179

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@311200 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 143 insertions, 181 deletions

diff --git a/lib/Tooling/ASTDiff/ASTDiff.cpp b/lib/Tooling/ASTDiff/ASTDiff.cpp
index 0441dbc78d..b0dd6012bd 100644
--- a/lib/Tooling/ASTDiff/ASTDiff.cpp
+++ b/lib/Tooling/ASTDiff/ASTDiff.cpp
@@ -82,26 +82,24 @@ private:
 class ASTDiff::Impl {
 public:
   SyntaxTree::Impl &T1, &T2;
-  bool IsMappingDone = false;
   Mapping TheMapping;
 
   Impl(SyntaxTree::Impl &T1, SyntaxTree::Impl &T2,
-       const ComparisonOptions &Options)
-      : T1(T1), T2(T2), Options(Options) {}
+       const ComparisonOptions &Options);
 
   /// Matches nodes one-by-one based on their similarity.
   void computeMapping();
 
-  std::vector<Match> getMatches(Mapping &M);
+  // Compute ChangeKind for each node based on similarity.
+  void computeChangeKinds(Mapping &M);
 
-  /// Finds an edit script that converts T1 to T2.
-  std::vector<Change> computeChanges(Mapping &M);
-
-  void printChangeImpl(raw_ostream &OS, const Change &Chg) const;
-  void printMatchImpl(raw_ostream &OS, const Match &M) const;
-
-  // Returns a mapping of identical subtrees.
-  Mapping matchTopDown() const;
+  NodeId getMapped(const std::unique_ptr<SyntaxTree::Impl> &Tree,
+                   NodeId Id) const {
+    if (&*Tree == &T1)
+      return TheMapping.getDst(Id);
+    assert(&*Tree == &T2 && "Invalid tree.");
+    return TheMapping.getSrc(Id);
+  }
 
 private:
   // Returns true if the two subtrees are identical.
@@ -112,6 +110,9 @@ private:
   // Returns false if the nodes must not be mached.
   bool isMatchingPossible(NodeId Id1, NodeId Id2) const;
 
+  // Returns true if the nodes' parents are matched.
+  bool haveSameParents(const Mapping &M, NodeId Id1, NodeId Id2) const;
+
   // Uses an optimal albeit slow algorithm to compute a mapping between two
   // subtrees, but only if both have fewer nodes than MaxSize.
   void addOptimalMapping(Mapping &M, NodeId Id1, NodeId Id2) const;
@@ -123,6 +124,9 @@ private:
   // Returns the node that has the highest degree of similarity.
   NodeId findCandidate(const Mapping &M, NodeId Id1) const;
 
+  // Returns a mapping of identical subtrees.
+  Mapping matchTopDown() const;
+
   // Tries to match any yet unmapped nodes, in a bottom-up fashion.
   void matchBottomUp(Mapping &M) const;
 
@@ -155,9 +159,12 @@ public:
   std::vector<NodeId> Leaves;
   // Maps preorder indices to postorder ones.
   std::vector<int> PostorderIds;
+  std::vector<NodeId> NodesBfs;
 
   int getSize() const { return Nodes.size(); }
   NodeId getRootId() const { return 0; }
+  PreorderIterator begin() const { return getRootId(); }
+  PreorderIterator end() const { return getSize(); }
 
   const Node &getNode(NodeId Id) const { return Nodes[Id]; }
   Node &getMutableNode(NodeId Id) { return Nodes[Id]; }
@@ -165,16 +172,10 @@ public:
   void addNode(Node &N) { Nodes.push_back(N); }
   int getNumberOfDescendants(NodeId Id) const;
   bool isInSubtree(NodeId Id, NodeId SubtreeRoot) const;
+  int findPositionInParent(NodeId Id, bool Shifted = false) const;
 
   std::string getNodeValue(NodeId Id) const;
-  std::string getNodeValue(const DynTypedNode &DTN) const;
-  /// Prints the node as "<type>[: <value>](<postorder-id)"
-  void printNode(NodeId Id) const { printNode(llvm::outs(), Id); }
-  void printNode(raw_ostream &OS, NodeId Id) const;
-
-  void printTree() const;
-  void printTree(NodeId Root) const;
-  void printTree(raw_ostream &OS, NodeId Root) const;
+  std::string getNodeValue(const Node &Node) const;
 
 private:
   /// Nodes in preorder.
@@ -302,6 +303,30 @@ SyntaxTree::Impl::Impl(SyntaxTree *Parent, Stmt *N, const ASTContext &AST)
   initTree();
 }
 
+static std::vector<NodeId> getSubtreePostorder(const SyntaxTree::Impl &Tree,
+                                               NodeId Root) {
+  std::vector<NodeId> Postorder;
+  std::function<void(NodeId)> Traverse = [&](NodeId Id) {
+    const Node &N = Tree.getNode(Id);
+    for (NodeId Child : N.Children)
+      Traverse(Child);
+    Postorder.push_back(Id);
+  };
+  Traverse(Root);
+  return Postorder;
+}
+
+static std::vector<NodeId> getSubtreeBfs(const SyntaxTree::Impl &Tree,
+                                         NodeId Root) {
+  std::vector<NodeId> Ids;
+  size_t Expanded = 0;
+  Ids.push_back(Root);
+  while (Expanded < Ids.size())
+    for (NodeId Child : Tree.getNode(Ids[Expanded++]).Children)
+      Ids.push_back(Child);
+  return Ids;
+}
+
 void SyntaxTree::Impl::initTree() {
   setLeftMostDescendants();
   int PostorderId = 0;
@@ -313,6 +338,7 @@ void SyntaxTree::Impl::initTree() {
     ++PostorderId;
   };
   PostorderTraverse(getRootId());
+  NodesBfs = getSubtreeBfs(*this, getRootId());
 }
 
 void SyntaxTree::Impl::setLeftMostDescendants() {
@@ -327,30 +353,6 @@ void SyntaxTree::Impl::setLeftMostDescendants() {
   }
 }
 
-static std::vector<NodeId> getSubtreePostorder(const SyntaxTree::Impl &Tree,
-                                               NodeId Root) {
-  std::vector<NodeId> Postorder;
-  std::function<void(NodeId)> Traverse = [&](NodeId Id) {
-    const Node &N = Tree.getNode(Id);
-    for (NodeId Child : N.Children)
-      Traverse(Child);
-    Postorder.push_back(Id);
-  };
-  Traverse(Root);
-  return Postorder;
-}
-
-static std::vector<NodeId> getSubtreeBfs(const SyntaxTree::Impl &Tree,
-                                         NodeId Root) {
-  std::vector<NodeId> Ids;
-  size_t Expanded = 0;
-  Ids.push_back(Root);
-  while (Expanded < Ids.size())
-    for (NodeId Child : Tree.getNode(Ids[Expanded++]).Children)
-      Ids.push_back(Child);
-  return Ids;
-}
-
 int SyntaxTree::Impl::getNumberOfDescendants(NodeId Id) const {
   return getNode(Id).RightMostDescendant - Id + 1;
 }
@@ -359,11 +361,29 @@ bool SyntaxTree::Impl::isInSubtree(NodeId Id, NodeId SubtreeRoot) const {
   return Id >= SubtreeRoot && Id <= getNode(SubtreeRoot).RightMostDescendant;
 }
 
+int SyntaxTree::Impl::findPositionInParent(NodeId Id, bool Shifted) const {
+  NodeId Parent = getNode(Id).Parent;
+  if (Parent.isInvalid())
+    return 0;
+  const auto &Siblings = getNode(Parent).Children;
+  int Position = 0;
+  for (size_t I = 0, E = Siblings.size(); I < E; ++I) {
+    if (Shifted)
+      Position += getNode(Siblings[I]).Shift;
+    if (Siblings[I] == Id) {
+      Position += I;
+      return Position;
+    }
+  }
+  llvm_unreachable("Node not found in parent's children.");
+}
+
 std::string SyntaxTree::Impl::getNodeValue(NodeId Id) const {
-  return getNodeValue(getNode(Id).ASTNode);
+  return getNodeValue(getNode(Id));
 }
 
-std::string SyntaxTree::Impl::getNodeValue(const DynTypedNode &DTN) const {
+std::string SyntaxTree::Impl::getNodeValue(const Node &N) const {
+  const DynTypedNode &DTN = N.ASTNode;
   if (auto *X = DTN.get<BinaryOperator>())
     return X->getOpcodeStr();
   if (auto *X = DTN.get<AccessSpecDecl>()) {
@@ -409,32 +429,6 @@ std::string SyntaxTree::Impl::getNodeValue(const DynTypedNode &DTN) const {
   llvm_unreachable("Fatal: unhandled AST node.\n");
 }
 
-void SyntaxTree::Impl::printTree() const { printTree(getRootId()); }
-void SyntaxTree::Impl::printTree(NodeId Root) const {
-  printTree(llvm::outs(), Root);
-}
-
-void SyntaxTree::Impl::printTree(raw_ostream &OS, NodeId Root) const {
-  const Node &N = getNode(Root);
-  for (int I = 0; I < N.Depth; ++I)
-    OS << " ";
-  printNode(OS, Root);
-  OS << "\n";
-  for (NodeId Child : N.Children)
-    printTree(OS, Child);
-}
-
-void SyntaxTree::Impl::printNode(raw_ostream &OS, NodeId Id) const {
-  if (Id.isInvalid()) {
-    OS << "None";
-    return;
-  }
-  OS << getNode(Id).getTypeLabel();
-  if (getNodeValue(Id) != "")
-    OS << ": " << getNodeValue(Id);
-  OS << "(" << PostorderIds[Id] << ")";
-}
-
 /// Identifies a node in a subtree by its postorder offset, starting at 1.
 struct SNodeId {
   int Id = 0;
@@ -736,8 +730,15 @@ bool ASTDiff::Impl::canBeAddedToMapping(const Mapping &M, NodeId Id1,
 }
 
 bool ASTDiff::Impl::isMatchingPossible(NodeId Id1, NodeId Id2) const {
-  return Options.isMatchingAllowed(T1.getNode(Id1).ASTNode,
-                                   T2.getNode(Id2).ASTNode);
+  return Options.isMatchingAllowed(T1.getNode(Id1), T2.getNode(Id2));
+}
+
+bool ASTDiff::Impl::haveSameParents(const Mapping &M, NodeId Id1,
+                                    NodeId Id2) const {
+  NodeId P1 = T1.getNode(Id1).Parent;
+  NodeId P2 = T2.getNode(Id2).Parent;
+  return (P1.isInvalid() && P2.isInvalid()) ||
+         (P1.isValid() && P2.isValid() && M.getDst(P1) == P2);
 }
 
 void ASTDiff::Impl::addOptimalMapping(Mapping &M, NodeId Id1,
@@ -770,7 +771,7 @@ double ASTDiff::Impl::getSimilarity(const Mapping &M, NodeId Id1,
 NodeId ASTDiff::Impl::findCandidate(const Mapping &M, NodeId Id1) const {
   NodeId Candidate;
   double HighestSimilarity = 0.0;
-  for (NodeId Id2 = 0, E = T2.getSize(); Id2 < E; ++Id2) {
+  for (NodeId Id2 : T2) {
     if (!isMatchingPossible(Id1, Id2))
       continue;
     if (M.hasDst(Id2))
@@ -855,99 +856,60 @@ Mapping ASTDiff::Impl::matchTopDown() const {
   return M;
 }
 
+ASTDiff::Impl::Impl(SyntaxTree::Impl &T1, SyntaxTree::Impl &T2,
+                    const ComparisonOptions &Options)
+    : T1(T1), T2(T2), Options(Options) {
+  computeMapping();
+  computeChangeKinds(TheMapping);
+}
+
 void ASTDiff::Impl::computeMapping() {
-  if (IsMappingDone)
-    return;
   TheMapping = matchTopDown();
   matchBottomUp(TheMapping);
-  IsMappingDone = true;
 }
 
-std::vector<Match> ASTDiff::Impl::getMatches(Mapping &M) {
-  std::vector<Match> Matches;
-  for (NodeId Id1 = 0, Id2, E = T1.getSize(); Id1 < E; ++Id1)
-    if ((Id2 = M.getDst(Id1)).isValid())
-      Matches.push_back({Id1, Id2});
-  return Matches;
-}
-
-std::vector<Change> ASTDiff::Impl::computeChanges(Mapping &M) {
-  std::vector<Change> Changes;
-  for (NodeId Id2 : getSubtreeBfs(T2, T2.getRootId())) {
-    const Node &N2 = T2.getNode(Id2);
-    NodeId Id1 = M.getSrc(Id2);
-    if (Id1.isValid()) {
-      assert(isMatchingPossible(Id1, Id2) && "Invalid matching.");
-      if (T1.getNodeValue(Id1) != T2.getNodeValue(Id2)) {
-        Changes.emplace_back(Update, Id1, Id2);
-      }
-      continue;
+void ASTDiff::Impl::computeChangeKinds(Mapping &M) {
+  for (NodeId Id1 : T1) {
+    if (!M.hasSrc(Id1)) {
+      T1.getMutableNode(Id1).ChangeKind = Delete;
+      T1.getMutableNode(Id1).Shift -= 1;
+    }
+  }
+  for (NodeId Id2 : T2) {
+    if (!M.hasDst(Id2)) {
+      T2.getMutableNode(Id2).ChangeKind = Insert;
+      T2.getMutableNode(Id2).Shift -= 1;
     }
-    NodeId P2 = N2.Parent;
-    NodeId P1 = M.getSrc(P2);
-    assert(P1.isValid() &&
-           "Parents must be matched for determining the change type.");
-    Node &Parent1 = T1.getMutableNode(P1);
-    const Node &Parent2 = T2.getNode(P2);
-    auto &Siblings1 = Parent1.Children;
-    const auto &Siblings2 = Parent2.Children;
-    size_t Position;
-    for (Position = 0; Position < Siblings2.size(); ++Position)
-      if (Siblings2[Position] == Id2 || Position >= Siblings1.size())
-        break;
-    Changes.emplace_back(Insert, Id2, P2, Position);
-    Node PatchNode;
-    PatchNode.Parent = P1;
-    PatchNode.LeftMostDescendant = N2.LeftMostDescendant;
-    PatchNode.RightMostDescendant = N2.RightMostDescendant;
-    PatchNode.Depth = N2.Depth;
-    PatchNode.ASTNode = N2.ASTNode;
-    // TODO update Depth if needed
-    NodeId PatchNodeId = T1.getSize();
-    // TODO maybe choose a different data structure for Children.
-    Siblings1.insert(Siblings1.begin() + Position, PatchNodeId);
-    T1.addNode(PatchNode);
-    M.link(PatchNodeId, Id2);
-  }
-  for (NodeId Id1 = 0; Id1 < T1.getSize(); ++Id1) {
+  }
+  for (NodeId Id1 : T1.NodesBfs) {
     NodeId Id2 = M.getDst(Id1);
     if (Id2.isInvalid())
-      Changes.emplace_back(Delete, Id1, Id2);
-  }
-  return Changes;
-}
-
-void ASTDiff::Impl::printChangeImpl(raw_ostream &OS, const Change &Chg) const {
-  switch (Chg.Kind) {
-  case Delete:
-    OS << "Delete ";
-    T1.printNode(OS, Chg.Src);
-    OS << "\n";
-    break;
-  case Update:
-    OS << "Update ";
-    T1.printNode(OS, Chg.Src);
-    OS << " to " << T2.getNodeValue(Chg.Dst) << "\n";
-    break;
-  case Insert:
-    OS << "Insert ";
-    T2.printNode(OS, Chg.Src);
-    OS << " into ";
-    T2.printNode(OS, Chg.Dst);
-    OS << " at " << Chg.Position << "\n";
-    break;
-  case Move:
-    llvm_unreachable("TODO");
-    break;
-  };
-}
-
-void ASTDiff::Impl::printMatchImpl(raw_ostream &OS, const Match &M) const {
-  OS << "Match ";
-  T1.printNode(OS, M.Src);
-  OS << " to ";
-  T2.printNode(OS, M.Dst);
-  OS << "\n";
+      continue;
+    if (!haveSameParents(M, Id1, Id2) ||
+        T1.findPositionInParent(Id1, true) !=
+            T2.findPositionInParent(Id2, true)) {
+      T1.getMutableNode(Id1).Shift -= 1;
+      T2.getMutableNode(Id2).Shift -= 1;
+    }
+  }
+  for (NodeId Id2 : T2.NodesBfs) {
+    NodeId Id1 = M.getSrc(Id2);
+    if (Id1.isInvalid())
+      continue;
+    Node &N1 = T1.getMutableNode(Id1);
+    Node &N2 = T2.getMutableNode(Id2);
+    if (Id1.isInvalid())
+      continue;
+    if (!haveSameParents(M, Id1, Id2) ||
+        T1.findPositionInParent(Id1, true) !=
+            T2.findPositionInParent(Id2, true)) {
+      N1.ChangeKind = N2.ChangeKind = Move;
+    }
+    if (T1.getNodeValue(Id1) != T2.getNodeValue(Id2)) {
+      N1.ChangeKind = N2.ChangeKind =
+          (N1.ChangeKind == Move ? UpdateMove : Update);
+    }
+  }
 }
 
 ASTDiff::ASTDiff(SyntaxTree &T1, SyntaxTree &T2,
@@ -956,28 +918,14 @@ ASTDiff::ASTDiff(SyntaxTree &T1, SyntaxTree &T2,
 
 ASTDiff::~ASTDiff() = default;
 
+NodeId ASTDiff::getMapped(const SyntaxTree &SourceTree, NodeId Id) const {
+  return DiffImpl->getMapped(SourceTree.TreeImpl, Id);
+}
+
 SyntaxTree::SyntaxTree(const ASTContext &AST)
     : TreeImpl(llvm::make_unique<SyntaxTree::Impl>(
           this, AST.getTranslationUnitDecl(), AST)) {}
 
-std::vector<Match> ASTDiff::getMatches() {
-  DiffImpl->computeMapping();
-  return DiffImpl->getMatches(DiffImpl->TheMapping);
-}
-
-std::vector<Change> ASTDiff::getChanges() {
-  DiffImpl->computeMapping();
-  return DiffImpl->computeChanges(DiffImpl->TheMapping);
-}
-
-void ASTDiff::printChange(raw_ostream &OS, const Change &Chg) const {
-  DiffImpl->printChangeImpl(OS, Chg);
-}
-
-void ASTDiff::printMatch(raw_ostream &OS, const Match &M) const {
-  DiffImpl->printMatchImpl(OS, M);
-}
-
 SyntaxTree::~SyntaxTree() = default;
 
 const ASTContext &SyntaxTree::getASTContext() const { return TreeImpl->AST; }
@@ -986,9 +934,19 @@ const Node &SyntaxTree::getNode(NodeId Id) const {
   return TreeImpl->getNode(Id);
 }
 
+int SyntaxTree::getSize() const { return TreeImpl->getSize(); }
 NodeId SyntaxTree::getRootId() const { return TreeImpl->getRootId(); }
+SyntaxTree::PreorderIterator SyntaxTree::begin() const {
+  return TreeImpl->begin();
+}
+SyntaxTree::PreorderIterator SyntaxTree::end() const { return TreeImpl->end(); }
 
-std::pair<unsigned, unsigned> SyntaxTree::getSourceRangeOffsets(const Node &N) const {
+int SyntaxTree::findPositionInParent(NodeId Id) const {
+  return TreeImpl->findPositionInParent(Id);
+}
+
+std::pair<unsigned, unsigned>
+SyntaxTree::getSourceRangeOffsets(const Node &N) const {
   const SourceManager &SrcMgr = TreeImpl->AST.getSourceManager();
   SourceRange Range = N.ASTNode.getSourceRange();
   SourceLocation BeginLoc = Range.getBegin();
@@ -1003,8 +961,12 @@ std::pair<unsigned, unsigned> SyntaxTree::getSourceRangeOffsets(const Node &N) c
   return {Begin, End};
 }
 
-std::string SyntaxTree::getNodeValue(const DynTypedNode &DTN) const {
-  return TreeImpl->getNodeValue(DTN);
+std::string SyntaxTree::getNodeValue(NodeId Id) const {
+  return TreeImpl->getNodeValue(Id);
+}
+
+std::string SyntaxTree::getNodeValue(const Node &N) const {
+  return TreeImpl->getNodeValue(N);
 }
 
 } // end namespace diff