[Dominators][CodeGen] Clean up MachineDominators

Summary: This is a cleanup patch for MachineDominatorTree. It would be an NFC, except for replacing custom DomTree verification with the generic one.

Reviewers: tstellar, tpr, nhaehnle, arsenm, NutshellySima, grosser, hliao

Reviewed By: arsenm

Subscribers: wdng, hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D67976

llvm-svn: 373101

Author: kuhar

llvm/include/llvm/CodeGen/MachineDominators.h

@@ -44,6 +44,8 @@ using MachineDomTreeNode = DomTreeNodeBase<MachineBasicBlock>;
 /// compute a normal dominator tree.
 ///
 class MachineDominatorTree : public MachineFunctionPass {
+  using DomTreeT = DomTreeBase<MachineBasicBlock>;
+
   /// Helper structure used to hold all the basic blocks
   /// involved in the split of a critical edge.
   struct CriticalEdge {
@@ -65,8 +67,8 @@ class MachineDominatorTree : public MachineFunctionPass {
   /// such as BB == elt.NewBB.
   mutable SmallSet<MachineBasicBlock *, 32> NewBBs;
 
-  /// The DominatorTreeBase that is used to compute a normal dominator tree
-  std::unique_ptr<DomTreeBase<MachineBasicBlock>> DT;
+  /// The DominatorTreeBase that is used to compute a normal dominator tree.
+  std::unique_ptr<DomTreeT> DT;
 
   /// Apply all the recorded critical edges to the DT.
   /// This updates the underlying DT information in a way that uses
@@ -80,8 +82,8 @@ class MachineDominatorTree : public MachineFunctionPass {
 
   MachineDominatorTree();
 
-  DomTreeBase<MachineBasicBlock> &getBase() {
-    if (!DT) DT.reset(new DomTreeBase<MachineBasicBlock>());
+  DomTreeT &getBase() {
+    if (!DT) DT.reset(new DomTreeT());
     applySplitCriticalEdges();
     return *DT;
   }
@@ -92,31 +94,30 @@ class MachineDominatorTree : public MachineFunctionPass {
   /// multiple blocks if we are computing post dominators.  For forward
   /// dominators, this will always be a single block (the entry node).
   ///
-  inline const SmallVectorImpl<MachineBasicBlock*> &getRoots() const {
+  const SmallVectorImpl<MachineBasicBlock*> &getRoots() const {
     applySplitCriticalEdges();
     return DT->getRoots();
   }
 
-  inline MachineBasicBlock *getRoot() const {
+  MachineBasicBlock *getRoot() const {
     applySplitCriticalEdges();
     return DT->getRoot();
   }
 
-  inline MachineDomTreeNode *getRootNode() const {
+  MachineDomTreeNode *getRootNode() const {
     applySplitCriticalEdges();
     return DT->getRootNode();
   }
 
   bool runOnMachineFunction(MachineFunction &F) override;
 
-  inline bool dominates(const MachineDomTreeNode* A,
-                        const MachineDomTreeNode* B) const {
+  bool dominates(const MachineDomTreeNode *A,
+                 const MachineDomTreeNode *B) const {
     applySplitCriticalEdges();
     return DT->dominates(A, B);
   }
 
-  inline bool dominates(const MachineBasicBlock* A,
-                        const MachineBasicBlock* B) const {
+  bool dominates(const MachineBasicBlock *A, const MachineBasicBlock *B) const {
     applySplitCriticalEdges();
     return DT->dominates(A, B);
   }
@@ -133,83 +134,77 @@ class MachineDominatorTree : public MachineFunctionPass {
     for (; &*I != A && &*I != B; ++I)
       /*empty*/ ;
 
-    //if(!DT.IsPostDominators) {
-      // A dominates B if it is found first in the basic block.
-      return &*I == A;
-    //} else {
-    //  // A post-dominates B if B is found first in the basic block.
-    //  return &*I == B;
-    //}
+    return &*I == A;
   }
 
-  inline bool properlyDominates(const MachineDomTreeNode* A,
-                                const MachineDomTreeNode* B) const {
+  bool properlyDominates(const MachineDomTreeNode *A,
+                         const MachineDomTreeNode *B) const {
     applySplitCriticalEdges();
     return DT->properlyDominates(A, B);
   }
 
-  inline bool properlyDominates(const MachineBasicBlock* A,
-                                const MachineBasicBlock* B) const {
+  bool properlyDominates(const MachineBasicBlock *A,
+                         const MachineBasicBlock *B) const {
     applySplitCriticalEdges();
     return DT->properlyDominates(A, B);
   }
 
   /// findNearestCommonDominator - Find nearest common dominator basic block
   /// for basic block A and B. If there is no such block then return NULL.
-  inline MachineBasicBlock *findNearestCommonDominator(MachineBasicBlock *A,
-                                                       MachineBasicBlock *B) {
+  MachineBasicBlock *findNearestCommonDominator(MachineBasicBlock *A,
+                                                MachineBasicBlock *B) {
     applySplitCriticalEdges();
     return DT->findNearestCommonDominator(A, B);
   }
 
-  inline MachineDomTreeNode *operator[](MachineBasicBlock *BB) const {
+  MachineDomTreeNode *operator[](MachineBasicBlock *BB) const {
     applySplitCriticalEdges();
     return DT->getNode(BB);
   }
 
   /// getNode - return the (Post)DominatorTree node for the specified basic
   /// block.  This is the same as using operator[] on this class.
   ///
-  inline MachineDomTreeNode *getNode(MachineBasicBlock *BB) const {
+  MachineDomTreeNode *getNode(MachineBasicBlock *BB) const {
     applySplitCriticalEdges();
     return DT->getNode(BB);
   }
 
   /// addNewBlock - Add a new node to the dominator tree information.  This
   /// creates a new node as a child of DomBB dominator node,linking it into
   /// the children list of the immediate dominator.
-  inline MachineDomTreeNode *addNewBlock(MachineBasicBlock *BB,
-                                         MachineBasicBlock *DomBB) {
+  MachineDomTreeNode *addNewBlock(MachineBasicBlock *BB,
+                                  MachineBasicBlock *DomBB) {
     applySplitCriticalEdges();
     return DT->addNewBlock(BB, DomBB);
   }
 
   /// changeImmediateDominator - This method is used to update the dominator
   /// tree information when a node's immediate dominator changes.
   ///
-  inline void changeImmediateDominator(MachineBasicBlock *N,
-                                       MachineBasicBlock* NewIDom) {
+  void changeImmediateDominator(MachineBasicBlock *N,
+                                MachineBasicBlock *NewIDom) {
     applySplitCriticalEdges();
     DT->changeImmediateDominator(N, NewIDom);
   }
 
-  inline void changeImmediateDominator(MachineDomTreeNode *N,
-                                       MachineDomTreeNode* NewIDom) {
+  void changeImmediateDominator(MachineDomTreeNode *N,
+                                MachineDomTreeNode *NewIDom) {
     applySplitCriticalEdges();
     DT->changeImmediateDominator(N, NewIDom);
   }
 
   /// eraseNode - Removes a node from  the dominator tree. Block must not
   /// dominate any other blocks. Removes node from its immediate dominator's
   /// children list. Deletes dominator node associated with basic block BB.
-  inline void eraseNode(MachineBasicBlock *BB) {
+  void eraseNode(MachineBasicBlock *BB) {
     applySplitCriticalEdges();
     DT->eraseNode(BB);
   }
 
   /// splitBlock - BB is split and now it has one successor. Update dominator
   /// tree to reflect this change.
-  inline void splitBlock(MachineBasicBlock* NewBB) {
+  void splitBlock(MachineBasicBlock* NewBB) {
     applySplitCriticalEdges();
     DT->splitBlock(NewBB);
   }

llvm/lib/CodeGen/MachineDominators.cpp

@@ -64,21 +64,11 @@ void MachineDominatorTree::releaseMemory() {
 }
 
 void MachineDominatorTree::verifyAnalysis() const {
-  if (DT && VerifyMachineDomInfo) {
-    MachineFunction &F = *getRoot()->getParent();
-
-    DomTreeBase<MachineBasicBlock> OtherDT;
-    OtherDT.recalculate(F);
-    if (getRootNode()->getBlock() != OtherDT.getRootNode()->getBlock() ||
-        DT->compare(OtherDT)) {
-      errs() << "MachineDominatorTree for function " << F.getName()
-            << " is not up to date!\nComputed:\n";
-      DT->print(errs());
-      errs() << "\nActual:\n";
-      OtherDT.print(errs());
+  if (DT && VerifyMachineDomInfo)
+    if (!DT->verify(DomTreeT::VerificationLevel::Basic)) {
+      errs() << "MachineDominatorTree verification failed\n";
       abort();
     }
-  }
 }
 
 void MachineDominatorTree::print(raw_ostream &OS, const Module*) const {