Merge significant portions of the DomTree and PostDomTree implementations.

The two remaining unmerged parts are DFSPass, and the Calculate().


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@42255 91177308-0d34-0410-b5e6-96231b3b80d8

5 files changed, 156 insertions, 152 deletions

diff --git a/include/llvm/Analysis/Dominators.h b/include/llvm/Analysis/Dominators.h
index f4c31a5..b9c85b5 100644
--- a/include/llvm/Analysis/Dominators.h
+++ b/include/llvm/Analysis/Dominators.h
@@ -275,6 +275,11 @@ public:
   virtual void dump();
   
 protected:
+  friend void Compress(DominatorTreeBase& DT, BasicBlock *VIn);
+  friend BasicBlock *Eval(DominatorTreeBase& DT, BasicBlock *V);
+  friend void Link(DominatorTreeBase& DT, BasicBlock *V,
+                   BasicBlock *W, InfoRec &WInfo);
+  
   /// updateDFSNumbers - Assign In and Out numbers to the nodes while walking
   /// dominator tree in dfs order.
   void updateDFSNumbers();
@@ -314,10 +319,6 @@ public:
 
 private:
   friend void DTcalculate(DominatorTree& DT, Function& F);
-  friend void DTCompress(DominatorTree& DT, BasicBlock *VIn);
-  friend BasicBlock *DTEval(DominatorTree& DT, BasicBlock *v);
-  friend void DTLink(DominatorTree& DT, BasicBlock *V,
-                     BasicBlock *W, InfoRec &WInfo);
   
   unsigned DFSPass(BasicBlock *V, unsigned N);
 };
diff --git a/include/llvm/Analysis/PostDominators.h b/include/llvm/Analysis/PostDominators.h
index 06a42da..b2a37ff 100644
--- a/include/llvm/Analysis/PostDominators.h
+++ b/include/llvm/Analysis/PostDominators.h
@@ -39,9 +39,6 @@ struct PostDominatorTree : public DominatorTreeBase {
 private:
   unsigned DFSPass(BasicBlock *V, unsigned N);
   friend void PDTcalculate(PostDominatorTree& PDT, Function &F);
-  friend void PDTCompress(PostDominatorTree& PDT, BasicBlock *V,
-                          InfoRec &VInfo);
-  friend BasicBlock *PDTEval(PostDominatorTree& PDT, BasicBlock *V);
   friend void PDTLink(PostDominatorTree& PDT,BasicBlock *V,
                       BasicBlock *W, InfoRec &WInfo);
 };
diff --git a/lib/Analysis/PostDominatorCalculation.h b/lib/Analysis/PostDominatorCalculation.h
index 0240c44..01dee0d 100644
--- a/lib/Analysis/PostDominatorCalculation.h
+++ b/lib/Analysis/PostDominatorCalculation.h
@@ -17,39 +17,6 @@
 
 namespace llvm {
 
-void PDTCompress(PostDominatorTree& PDT, BasicBlock *V,
-                 PostDominatorTree::InfoRec &VInfo) {
-  BasicBlock *VAncestor = VInfo.Ancestor;
-  PostDominatorTree::InfoRec &VAInfo = PDT.Info[VAncestor];
-  if (VAInfo.Ancestor == 0)
-    return;
-  
-  PDTCompress(PDT, VAncestor, VAInfo);
-  
-  BasicBlock *VAncestorLabel = VAInfo.Label;
-  BasicBlock *VLabel = VInfo.Label;
-  if (PDT.Info[VAncestorLabel].Semi < PDT.Info[VLabel].Semi)
-    VInfo.Label = VAncestorLabel;
-  
-  VInfo.Ancestor = VAInfo.Ancestor;
-}
-
-BasicBlock *PDTEval(PostDominatorTree& PDT, BasicBlock *V) {
-  PostDominatorTree::InfoRec &VInfo = PDT.Info[V];
-
-  // Higher-complexity but faster implementation
-  if (VInfo.Ancestor == 0)
-    return V;
-  PDTCompress(PDT, V, VInfo);
-  return VInfo.Label;
-}
-
-void PDTLink(PostDominatorTree& PDT, BasicBlock *V, BasicBlock *W, 
-             PostDominatorTree::InfoRec &WInfo) {
-  // Higher-complexity but faster implementation
-  WInfo.Ancestor = V;
-}
-
 void PDTcalculate(PostDominatorTree& PDT, Function &F) {
   // Step #0: Scan the function looking for the root nodes of the post-dominance
   // relationships.  These blocks, which have no successors, end with return and
@@ -82,7 +49,7 @@ void PDTcalculate(PostDominatorTree& PDT, Function &F) {
     // Step #2: Calculate the semidominators of all vertices
     for (succ_iterator SI = succ_begin(W), SE = succ_end(W); SI != SE; ++SI)
       if (PDT.Info.count(*SI)) {  // Only if this predecessor is reachable!
-        unsigned SemiU = PDT.Info[PDTEval(PDT, *SI)].Semi;
+        unsigned SemiU = PDT.Info[Eval(PDT, *SI)].Semi;
         if (SemiU < WInfo.Semi)
           WInfo.Semi = SemiU;
       }
@@ -90,14 +57,14 @@ void PDTcalculate(PostDominatorTree& PDT, Function &F) {
     PDT.Info[PDT.Vertex[WInfo.Semi]].Bucket.push_back(W);
     
     BasicBlock *WParent = WInfo.Parent;
-    PDTLink(PDT, WParent, W, WInfo);
+    Link(PDT, WParent, W, WInfo);
     
     // Step #3: Implicitly define the immediate dominator of vertices
     std::vector<BasicBlock*> &WParentBucket = PDT.Info[WParent].Bucket;
     while (!WParentBucket.empty()) {
       BasicBlock *V = WParentBucket.back();
       WParentBucket.pop_back();
-      BasicBlock *U = PDTEval(PDT, V);
+      BasicBlock *U = Eval(PDT, V);
       PDT.IDoms[V] = PDT.Info[U].Semi < PDT.Info[V].Semi ? U : WParent;
     }
   }
diff --git a/lib/VMCore/DominatorCalculation.h b/lib/VMCore/DominatorCalculation.h
index ee7e674..de915be 100644
--- a/lib/VMCore/DominatorCalculation.h
+++ b/lib/VMCore/DominatorCalculation.h
@@ -33,112 +33,6 @@
 
 namespace llvm {
 
-void DTCompress(DominatorTree& DT, BasicBlock *VIn) {
-
-  std::vector<BasicBlock *> Work;
-  SmallPtrSet<BasicBlock *, 32> Visited;
-  BasicBlock *VInAncestor = DT.Info[VIn].Ancestor;
-  DominatorTree::InfoRec &VInVAInfo = DT.Info[VInAncestor];
-
-  if (VInVAInfo.Ancestor != 0)
-    Work.push_back(VIn);
-  
-  while (!Work.empty()) {
-    BasicBlock *V = Work.back();
-    DominatorTree::InfoRec &VInfo = DT.Info[V];
-    BasicBlock *VAncestor = VInfo.Ancestor;
-    DominatorTree::InfoRec &VAInfo = DT.Info[VAncestor];
-
-    // Process Ancestor first
-    if (Visited.insert(VAncestor) &&
-        VAInfo.Ancestor != 0) {
-      Work.push_back(VAncestor);
-      continue;
-    } 
-    Work.pop_back(); 
-
-    // Update VInfo based on Ancestor info
-    if (VAInfo.Ancestor == 0)
-      continue;
-    BasicBlock *VAncestorLabel = VAInfo.Label;
-    BasicBlock *VLabel = VInfo.Label;
-    if (DT.Info[VAncestorLabel].Semi < DT.Info[VLabel].Semi)
-      VInfo.Label = VAncestorLabel;
-    VInfo.Ancestor = VAInfo.Ancestor;
-  }
-}
-
-BasicBlock *DTEval(DominatorTree& DT, BasicBlock *V) {
-  DominatorTree::InfoRec &VInfo = DT.Info[V];
-#if !BALANCE_IDOM_TREE
-  // Higher-complexity but faster implementation
-  if (VInfo.Ancestor == 0)
-    return V;
-  DTCompress(DT, V);
-  return VInfo.Label;
-#else
-  // Lower-complexity but slower implementation
-  if (VInfo.Ancestor == 0)
-    return VInfo.Label;
-  DTCompress(DT, V);
-  BasicBlock *VLabel = VInfo.Label;
-
-  BasicBlock *VAncestorLabel = DT.Info[VInfo.Ancestor].Label;
-  if (DT.Info[VAncestorLabel].Semi >= DT.Info[VLabel].Semi)
-    return VLabel;
-  else
-    return VAncestorLabel;
-#endif
-}
-
-void DTLink(DominatorTree& DT, BasicBlock *V, BasicBlock *W,
-            DominatorTree::InfoRec &WInfo) {
-#if !BALANCE_IDOM_TREE
-  // Higher-complexity but faster implementation
-  WInfo.Ancestor = V;
-#else
-  // Lower-complexity but slower implementation
-  BasicBlock *WLabel = WInfo.Label;
-  unsigned WLabelSemi = Info[WLabel].Semi;
-  BasicBlock *S = W;
-  InfoRec *SInfo = &Info[S];
-
-  BasicBlock *SChild = SInfo->Child;
-  InfoRec *SChildInfo = &Info[SChild];
-
-  while (WLabelSemi < Info[SChildInfo->Label].Semi) {
-    BasicBlock *SChildChild = SChildInfo->Child;
-    if (SInfo->Size+Info[SChildChild].Size >= 2*SChildInfo->Size) {
-      SChildInfo->Ancestor = S;
-      SInfo->Child = SChild = SChildChild;
-      SChildInfo = &Info[SChild];
-    } else {
-      SChildInfo->Size = SInfo->Size;
-      S = SInfo->Ancestor = SChild;
-      SInfo = SChildInfo;
-      SChild = SChildChild;
-      SChildInfo = &Info[SChild];
-    }
-  }
-
-  InfoRec &VInfo = Info[V];
-  SInfo->Label = WLabel;
-
-  assert(V != W && "The optimization here will not work in this case!");
-  unsigned WSize = WInfo.Size;
-  unsigned VSize = (VInfo.Size += WSize);
-
-  if (VSize < 2*WSize)
-    std::swap(S, VInfo.Child);
-
-  while (S) {
-    SInfo = &Info[S];
-    SInfo->Ancestor = V;
-    S = SInfo->Child;
-  }
-#endif
-}
-
 void DTcalculate(DominatorTree& DT, Function &F) {
   BasicBlock* Root = DT.Roots[0];
 
@@ -158,7 +52,7 @@ void DTcalculate(DominatorTree& DT, Function &F) {
     // Step #2: Calculate the semidominators of all vertices
     for (pred_iterator PI = pred_begin(W), E = pred_end(W); PI != E; ++PI)
       if (DT.Info.count(*PI)) {  // Only if this predecessor is reachable!
-        unsigned SemiU = DT.Info[DTEval(DT, *PI)].Semi;
+        unsigned SemiU = DT.Info[Eval(DT, *PI)].Semi;
         if (SemiU < WInfo.Semi)
           WInfo.Semi = SemiU;
       }
@@ -166,14 +60,14 @@ void DTcalculate(DominatorTree& DT, Function &F) {
     DT.Info[DT.Vertex[WInfo.Semi]].Bucket.push_back(W);
 
     BasicBlock *WParent = WInfo.Parent;
-    DTLink(DT, WParent, W, WInfo);
+    Link(DT, WParent, W, WInfo);
 
     // Step #3: Implicitly define the immediate dominator of vertices
     std::vector<BasicBlock*> &WParentBucket = DT.Info[WParent].Bucket;
     while (!WParentBucket.empty()) {
       BasicBlock *V = WParentBucket.back();
       WParentBucket.pop_back();
-      BasicBlock *U = DTEval(DT, V);
+      BasicBlock *U = Eval(DT, V);
       DT.IDoms[V] = DT.Info[U].Semi < DT.Info[V].Semi ? U : WParent;
     }
   }
diff --git a/lib/VMCore/DominatorInternals.cpp b/lib/VMCore/DominatorInternals.cpp
new file mode 100644
index 0000000..b7c8d32
--- /dev/null
+++ b/lib/VMCore/DominatorInternals.cpp
@@ -0,0 +1,145 @@
+//==- DominatorInternals.cpp - Dominator Calculation -------------*- C++ -*-==//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file was developed by Owen Anderson and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_ANALYSIS_DOMINATOR_INTERNALS_H
+#define LLVM_ANALYSIS_DOMINATOR_INTERNALS_H
+
+#include "llvm/Analysis/Dominators.h"
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/SmallPtrSet.h"
+//===----------------------------------------------------------------------===//
+//
+// DominatorTree construction - This pass constructs immediate dominator
+// information for a flow-graph based on the algorithm described in this
+// document:
+//
+//   A Fast Algorithm for Finding Dominators in a Flowgraph
+//   T. Lengauer & R. Tarjan, ACM TOPLAS July 1979, pgs 121-141.
+//
+// This implements both the O(n*ack(n)) and the O(n*log(n)) versions of EVAL and
+// LINK, but it turns out that the theoretically slower O(n*log(n))
+// implementation is actually faster than the "efficient" algorithm (even for
+// large CFGs) because the constant overheads are substantially smaller.  The
+// lower-complexity version can be enabled with the following #define:
+//
+#define BALANCE_IDOM_TREE 0
+//
+//===----------------------------------------------------------------------===//
+
+namespace llvm {
+
+void Compress(DominatorTreeBase& DT, BasicBlock *VIn) {
+
+  std::vector<BasicBlock *> Work;
+  SmallPtrSet<BasicBlock *, 32> Visited;
+  BasicBlock *VInAncestor = DT.Info[VIn].Ancestor;
+  DominatorTreeBase::InfoRec &VInVAInfo = DT.Info[VInAncestor];
+
+  if (VInVAInfo.Ancestor != 0)
+    Work.push_back(VIn);
+  
+  while (!Work.empty()) {
+    BasicBlock *V = Work.back();
+    DominatorTree::InfoRec &VInfo = DT.Info[V];
+    BasicBlock *VAncestor = VInfo.Ancestor;
+    DominatorTreeBase::InfoRec &VAInfo = DT.Info[VAncestor];
+
+    // Process Ancestor first
+    if (Visited.insert(VAncestor) &&
+        VAInfo.Ancestor != 0) {
+      Work.push_back(VAncestor);
+      continue;
+    } 
+    Work.pop_back(); 
+
+    // Update VInfo based on Ancestor info
+    if (VAInfo.Ancestor == 0)
+      continue;
+    BasicBlock *VAncestorLabel = VAInfo.Label;
+    BasicBlock *VLabel = VInfo.Label;
+    if (DT.Info[VAncestorLabel].Semi < DT.Info[VLabel].Semi)
+      VInfo.Label = VAncestorLabel;
+    VInfo.Ancestor = VAInfo.Ancestor;
+  }
+}
+
+BasicBlock *Eval(DominatorTreeBase& DT, BasicBlock *V) {
+                 DominatorTreeBase::InfoRec &VInfo = DT.Info[V];
+#if !BALANCE_IDOM_TREE
+  // Higher-complexity but faster implementation
+  if (VInfo.Ancestor == 0)
+    return V;
+  Compress(DT, V);
+  return VInfo.Label;
+#else
+  // Lower-complexity but slower implementation
+  if (VInfo.Ancestor == 0)
+    return VInfo.Label;
+  Compress(DT, V);
+  BasicBlock *VLabel = VInfo.Label;
+
+  BasicBlock *VAncestorLabel = DT.Info[VInfo.Ancestor].Label;
+  if (DT.Info[VAncestorLabel].Semi >= DT.Info[VLabel].Semi)
+    return VLabel;
+  else
+    return VAncestorLabel;
+#endif
+}
+
+void Link(DominatorTreeBase& DT, BasicBlock *V, BasicBlock *W,
+          DominatorTreeBase::InfoRec &WInfo) {
+#if !BALANCE_IDOM_TREE
+  // Higher-complexity but faster implementation
+  WInfo.Ancestor = V;
+#else
+  // Lower-complexity but slower implementation
+  BasicBlock *WLabel = WInfo.Label;
+  unsigned WLabelSemi = DT.Info[WLabel].Semi;
+  BasicBlock *S = W;
+  InfoRec *SInfo = &DT.Info[S];
+
+  BasicBlock *SChild = SInfo->Child;
+  InfoRec *SChildInfo = &DT.Info[SChild];
+
+  while (WLabelSemi < DT.Info[SChildInfo->Label].Semi) {
+    BasicBlock *SChildChild = SChildInfo->Child;
+    if (SInfo->Size+DT.Info[SChildChild].Size >= 2*SChildInfo->Size) {
+      SChildInfo->Ancestor = S;
+      SInfo->Child = SChild = SChildChild;
+      SChildInfo = &DT.Info[SChild];
+    } else {
+      SChildInfo->Size = SInfo->Size;
+      S = SInfo->Ancestor = SChild;
+      SInfo = SChildInfo;
+      SChild = SChildChild;
+      SChildInfo = &DT.Info[SChild];
+    }
+  }
+
+  DominatorTreeBase::InfoRec &VInfo = DT.Info[V];
+  SInfo->Label = WLabel;
+
+  assert(V != W && "The optimization here will not work in this case!");
+  unsigned WSize = WInfo.Size;
+  unsigned VSize = (VInfo.Size += WSize);
+
+  if (VSize < 2*WSize)
+    std::swap(S, VInfo.Child);
+
+  while (S) {
+    SInfo = &DT.Info[S];
+    SInfo->Ancestor = V;
+    S = SInfo->Child;
+  }
+#endif
+}
+
+}
+
+#endif
\ No newline at end of file