[ dwarfdump ] Add symbolic dump of known DWARF attribute values.

[oota-llvm.git] / include / llvm / Support / GenericDomTree.h

diff --git a/include/llvm/Support/GenericDomTree.h b/include/llvm/Support/GenericDomTree.h
index 3c2d7a826fdcdb8b0524e4267cb9b7a81f2b43e1..6bc4b4425e71a06348b4677d478518d99b677f49 100644 (file)
--- a/include/llvm/Support/GenericDomTree.h
+++ b/include/llvm/Support/GenericDomTree.h
@@ -15,8 +15,8 @@
 ///
 //===----------------------------------------------------------------------===//
 
-#ifndef LLVM_SUPPORT_GENERIC_DOM_TREE_H
-#define LLVM_SUPPORT_GENERIC_DOM_TREE_H
+#ifndef LLVM_SUPPORT_GENERICDOMTREE_H
+#define LLVM_SUPPORT_GENERICDOMTREE_H
 
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/DepthFirstIterator.h"
@@ -330,6 +330,10 @@ public:
     return DomTreeNodes.lookup(BB);
   }
 
+  inline DomTreeNodeBase<NodeT> *operator[](NodeT *BB) const {
+    return getNode(BB);
+  }
+
   /// getRootNode - This returns the entry node for the CFG of the function.  If
   /// this tree represents the post-dominance relations for a function, however,
   /// this root may be a node with the block == NULL.  This is the case when
@@ -453,6 +457,21 @@ public:
     DomTreeNodeBase<NodeT> *NodeA = getNode(A);
     DomTreeNodeBase<NodeT> *NodeB = getNode(B);
 
+    // If we have DFS info, then we can avoid all allocations by just querying
+    // it from each IDom. Note that because we call 'dominates' twice above, we
+    // expect to call through this code at most 16 times in a row without
+    // building valid DFS information. This is important as below is a *very*
+    // slow tree walk.
+    if (DFSInfoValid) {
+      DomTreeNodeBase<NodeT> *IDomA = NodeA->getIDom();
+      while (IDomA) {
+        if (NodeB->DominatedBy(IDomA))
+          return IDomA->getBlock();
+        IDomA = IDomA->getIDom();
+      }
+      return nullptr;
+    }
+
     // Collect NodeA dominators set.
     SmallPtrSet<DomTreeNodeBase<NodeT>*, 16> NodeADoms;
     NodeADoms.insert(NodeA);
@@ -489,7 +508,7 @@ public:
   /// creates a new node as a child of DomBB dominator node,linking it into
   /// the children list of the immediate dominator.
   DomTreeNodeBase<NodeT> *addNewBlock(NodeT *BB, NodeT *DomBB) {
-    assert(getNode(BB) == 0 && "Block already in dominator tree!");
+    assert(getNode(BB) == nullptr && "Block already in dominator tree!");
     DomTreeNodeBase<NodeT> *IDomNode = getNode(DomBB);
     assert(IDomNode && "Not immediate dominator specified for block!");
     DFSInfoValid = false;
@@ -636,7 +655,7 @@ protected:
     // immediate dominator.
     NodeT *IDom = getIDom(BB);
 
-    assert(IDom || this->DomTreeNodes[NULL]);
+    assert(IDom || this->DomTreeNodes[nullptr]);
     DomTreeNodeBase<NodeT> *IDomNode = getNodeForBlock(IDom);
 
     // Add a new tree node for this NodeT, and link it as a child of