[GraphDiff] Make InverseGraph a property of a GraphDiff.

Summary:
Treating a graph in reverse is a property of the GraphDiff and should instead be a template argument, just like IsPostDom is one for DomTrees.
If it's just an argument to all methods, we could have mismatches between the constructor of the GraphDiff which may reverse the updates when filtering them, and the calls retrieving the filtered delete/insert updates.
Also, since this will be used in IDF, where we're using a DomTree, this creates a cleaner interface for the GraphTraits to use the existing template argument of DomTreeBase.

Separate patch from the one adding GraphDiff, so get a clear diff of what changed.

Reviewers: timshen, kuhar

Subscribers: sanjoy, llvm-commits, jlebar

Differential Revision: https://reviews.llvm.org/D50687

llvm-svn: 339699

diff --git a/llvm/include/llvm/IR/CFGDiff.h b/llvm/include/llvm/IR/CFGDiff.h
index 51745b25dd18a7baf7db5d0f343bc958def63100..da4373f7bce23c44cbd7903c7e1b250e7225b8fe 100644 (file)
--- a/llvm/include/llvm/IR/CFGDiff.h
+++ b/llvm/include/llvm/IR/CFGDiff.h
@@ -78,7 +78,7 @@ namespace llvm {
 // newly inserted. The current diff treats the CFG as a graph rather than a
 // multigraph. Added edges are pruned to be unique, and deleted edges will
 // remove all existing edges between two blocks.
-template <typename NodePtr> class GraphDiff {
+template <typename NodePtr, bool InverseGraph = false> class GraphDiff {
   using UpdateMapType = SmallDenseMap<NodePtr, SmallVector<NodePtr, 2>>;
   UpdateMapType SuccInsert;
   UpdateMapType SuccDelete;
@@ -102,7 +102,7 @@ template <typename NodePtr> class GraphDiff {
 
 public:
   GraphDiff() {}
-  GraphDiff(ArrayRef<cfg::Update<NodePtr>> Updates, bool InverseGraph = false) {
+  GraphDiff(ArrayRef<cfg::Update<NodePtr>> Updates) {
     SmallVector<cfg::Update<NodePtr>, 4> LegalizedUpdates;
     cfg::LegalizeUpdates<NodePtr>(Updates, LegalizedUpdates, InverseGraph);
     for (auto U : LegalizedUpdates) {
@@ -116,8 +116,7 @@ public:
     }
   }
 
-  bool ignoreChild(const NodePtr BB, NodePtr EdgeEnd, bool InverseEdge,
-                   bool InverseGraph) const {
+  bool ignoreChild(const NodePtr BB, NodePtr EdgeEnd, bool InverseEdge) const {
     auto &DeleteChildren =
         (InverseEdge != InverseGraph) ? PredDelete : SuccDelete;
     auto It = DeleteChildren.find(BB);
@@ -128,8 +127,7 @@ public:
   }
 
   iterator_range<typename SmallVectorImpl<NodePtr>::const_iterator>
-  getAddedChildren(const NodePtr BB, bool InverseEdge,
-                   bool InverseGraph) const {
+  getAddedChildren(const NodePtr BB, bool InverseEdge) const {
     auto &InsertChildren =
         (InverseEdge != InverseGraph) ? PredInsert : SuccInsert;
     auto It = InsertChildren.find(BB);
@@ -159,7 +157,7 @@ public:
 };
 
 template <bool InverseGraph = false> struct CFGViewSuccessors {
-  using DataRef = const GraphDiff<BasicBlock *> *;
+  using DataRef = const GraphDiff<BasicBlock *, InverseGraph> *;
   using NodeRef = std::pair<DataRef, BasicBlock *>;
 
   using ExistingChildIterator =
@@ -168,7 +166,7 @@ template <bool InverseGraph = false> struct CFGViewSuccessors {
     BasicBlock *BB;
     DeletedEdgesFilter(BasicBlock *BB) : BB(BB){};
     bool operator()(NodeRef N) const {
-      return !N.first->ignoreChild(BB, N.second, false, InverseGraph);
+      return !N.first->ignoreChild(BB, N.second, false);
     }
   };
   using FilterExistingChildrenIterator =
@@ -182,7 +180,7 @@ template <bool InverseGraph = false> struct CFGViewSuccessors {
                       AddNewChildrenIterator>;
 
   static ChildIteratorType child_begin(NodeRef N) {
-    auto InsertVec = N.first->getAddedChildren(N.second, false, InverseGraph);
+    auto InsertVec = N.first->getAddedChildren(N.second, false);
     // filter iterator init:
     auto firstit = make_filter_range(
         make_range<ExistingChildIterator>({succ_begin(N.second), N.first},
@@ -197,7 +195,7 @@ template <bool InverseGraph = false> struct CFGViewSuccessors {
   }
 
   static ChildIteratorType child_end(NodeRef N) {
-    auto InsertVec = N.first->getAddedChildren(N.second, false, InverseGraph);
+    auto InsertVec = N.first->getAddedChildren(N.second, false);
     // filter iterator init:
     auto firstit = make_filter_range(
         make_range<ExistingChildIterator>({succ_end(N.second), N.first},
@@ -213,7 +211,7 @@ template <bool InverseGraph = false> struct CFGViewSuccessors {
 };
 
 template <bool InverseGraph = false> struct CFGViewPredecessors {
-  using DataRef = const GraphDiff<BasicBlock *> *;
+  using DataRef = const GraphDiff<BasicBlock *, InverseGraph> *;
   using NodeRef = std::pair<DataRef, BasicBlock *>;
 
   using ExistingChildIterator =
@@ -222,7 +220,7 @@ template <bool InverseGraph = false> struct CFGViewPredecessors {
     BasicBlock *BB;
     DeletedEdgesFilter(BasicBlock *BB) : BB(BB){};
     bool operator()(NodeRef N) const {
-      return !N.first->ignoreChild(BB, N.second, true, InverseGraph);
+      return !N.first->ignoreChild(BB, N.second, true);
     }
   };
   using FilterExistingChildrenIterator =
@@ -236,7 +234,7 @@ template <bool InverseGraph = false> struct CFGViewPredecessors {
                       AddNewChildrenIterator>;
 
   static ChildIteratorType child_begin(NodeRef N) {
-    auto InsertVec = N.first->getAddedChildren(N.second, true, InverseGraph);
+    auto InsertVec = N.first->getAddedChildren(N.second, true);
     // filter iterator init:
     auto firstit = make_filter_range(
         make_range<ExistingChildIterator>({pred_begin(N.second), N.first},
@@ -251,7 +249,7 @@ template <bool InverseGraph = false> struct CFGViewPredecessors {
   }
 
   static ChildIteratorType child_end(NodeRef N) {
-    auto InsertVec = N.first->getAddedChildren(N.second, true, InverseGraph);
+    auto InsertVec = N.first->getAddedChildren(N.second, true);
     // filter iterator init:
     auto firstit = make_filter_range(
         make_range<ExistingChildIterator>({pred_end(N.second), N.first},
@@ -267,19 +265,20 @@ template <bool InverseGraph = false> struct CFGViewPredecessors {
 };
 
 template <>
-struct GraphTraits<std::pair<const GraphDiff<BasicBlock *> *, BasicBlock *>>
+struct GraphTraits<
+    std::pair<const GraphDiff<BasicBlock *, false> *, BasicBlock *>>
     : CFGViewSuccessors<false> {};
 template <>
 struct GraphTraits<
-    std::pair<const GraphDiff<Inverse<BasicBlock *>> *, BasicBlock *>>
+    std::pair<const GraphDiff<BasicBlock *, true> *, BasicBlock *>>
     : CFGViewSuccessors<true> {};
 template <>
 struct GraphTraits<
-    std::pair<const GraphDiff<BasicBlock *> *, Inverse<BasicBlock *>>>
+    std::pair<const GraphDiff<BasicBlock *, false> *, Inverse<BasicBlock *>>>
     : CFGViewPredecessors<false> {};
 template <>
 struct GraphTraits<
-    std::pair<const GraphDiff<Inverse<BasicBlock *>> *, Inverse<BasicBlock *>>>
+    std::pair<const GraphDiff<BasicBlock *, true> *, Inverse<BasicBlock *>>>
     : CFGViewPredecessors<true> {};
 } // end namespace llvm