Factor the calculation details for PostDomTree out of PostDominators.cpp and

into a separate header file.

Next step: merging PostDominatorCalculation.h with DominatorCalculation.h.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@42251 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 1 insertions, 142 deletions

diff --git a/lib/Analysis/PostDominators.cpp b/lib/Analysis/PostDominators.cpp
index 69e9cbe26b..b8d833e23d 100644
--- a/lib/Analysis/PostDominators.cpp
+++ b/lib/Analysis/PostDominators.cpp
@@ -16,6 +16,7 @@
 #include "llvm/Support/CFG.h"
 #include "llvm/ADT/DepthFirstIterator.h"
 #include "llvm/ADT/SetOperations.h"
+#include "PostDominatorCalculation.h"
 using namespace llvm;
 
 //===----------------------------------------------------------------------===//
@@ -72,148 +73,6 @@ unsigned PostDominatorTree::DFSPass(BasicBlock *V, unsigned N) {
   return N;
 }
 
-void PostDominatorTree::Compress(BasicBlock *V, InfoRec &VInfo) {
-  BasicBlock *VAncestor = VInfo.Ancestor;
-  InfoRec &VAInfo = Info[VAncestor];
-  if (VAInfo.Ancestor == 0)
-    return;
-  
-  Compress(VAncestor, VAInfo);
-  
-  BasicBlock *VAncestorLabel = VAInfo.Label;
-  BasicBlock *VLabel = VInfo.Label;
-  if (Info[VAncestorLabel].Semi < Info[VLabel].Semi)
-    VInfo.Label = VAncestorLabel;
-  
-  VInfo.Ancestor = VAInfo.Ancestor;
-}
-
-BasicBlock *PostDominatorTree::Eval(BasicBlock *V) {
-  InfoRec &VInfo = Info[V];
-
-  // Higher-complexity but faster implementation
-  if (VInfo.Ancestor == 0)
-    return V;
-  Compress(V, VInfo);
-  return VInfo.Label;
-}
-
-void PostDominatorTree::Link(BasicBlock *V, BasicBlock *W, 
-                                   InfoRec &WInfo) {
-  // Higher-complexity but faster implementation
-  WInfo.Ancestor = V;
-}
-
-void PostDominatorTree::calculate(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
-  // unwind instructions.
-  for (Function::iterator I = F.begin(), E = F.end(); I != E; ++I) {
-    TerminatorInst *Insn = I->getTerminator();
-    if (Insn->getNumSuccessors() == 0) {
-      // Unreachable block is not a root node.
-      if (!isa<UnreachableInst>(Insn))
-        Roots.push_back(I);
-    }
-    
-    // Prepopulate maps so that we don't get iterator invalidation issues later.
-    IDoms[I] = 0;
-    DomTreeNodes[I] = 0;
-  }
-  
-  Vertex.push_back(0);
-  
-  // Step #1: Number blocks in depth-first order and initialize variables used
-  // in later stages of the algorithm.
-  unsigned N = 0;
-  for (unsigned i = 0, e = Roots.size(); i != e; ++i)
-    N = DFSPass(Roots[i], N);
-  
-  for (unsigned i = N; i >= 2; --i) {
-    BasicBlock *W = Vertex[i];
-    InfoRec &WInfo = Info[W];
-    
-    // Step #2: Calculate the semidominators of all vertices
-    for (succ_iterator SI = succ_begin(W), SE = succ_end(W); SI != SE; ++SI)
-      if (Info.count(*SI)) {  // Only if this predecessor is reachable!
-        unsigned SemiU = Info[Eval(*SI)].Semi;
-        if (SemiU < WInfo.Semi)
-          WInfo.Semi = SemiU;
-      }
-        
-    Info[Vertex[WInfo.Semi]].Bucket.push_back(W);
-    
-    BasicBlock *WParent = WInfo.Parent;
-    Link(WParent, W, WInfo);
-    
-    // Step #3: Implicitly define the immediate dominator of vertices
-    std::vector<BasicBlock*> &WParentBucket = Info[WParent].Bucket;
-    while (!WParentBucket.empty()) {
-      BasicBlock *V = WParentBucket.back();
-      WParentBucket.pop_back();
-      BasicBlock *U = Eval(V);
-      IDoms[V] = Info[U].Semi < Info[V].Semi ? U : WParent;
-    }
-  }
-  
-  // Step #4: Explicitly define the immediate dominator of each vertex
-  for (unsigned i = 2; i <= N; ++i) {
-    BasicBlock *W = Vertex[i];
-    BasicBlock *&WIDom = IDoms[W];
-    if (WIDom != Vertex[Info[W].Semi])
-      WIDom = IDoms[WIDom];
-  }
-  
-  if (Roots.empty()) return;
-
-  // Add a node for the root.  This node might be the actual root, if there is
-  // one exit block, or it may be the virtual exit (denoted by (BasicBlock *)0)
-  // which postdominates all real exits if there are multiple exit blocks.
-  BasicBlock *Root = Roots.size() == 1 ? Roots[0] : 0;
-  DomTreeNodes[Root] = RootNode = new DomTreeNode(Root, 0);
-  
-  // Loop over all of the reachable blocks in the function...
-  for (Function::iterator I = F.begin(), E = F.end(); I != E; ++I)
-    if (BasicBlock *ImmPostDom = getIDom(I)) {  // Reachable block.
-      DomTreeNode *&BBNode = DomTreeNodes[I];
-      if (!BBNode) {  // Haven't calculated this node yet?
-                      // Get or calculate the node for the immediate dominator
-        DomTreeNode *IPDomNode = getNodeForBlock(ImmPostDom);
-        
-        // Add a new tree node for this BasicBlock, and link it as a child of
-        // IDomNode
-        DomTreeNode *C = new DomTreeNode(I, IPDomNode);
-        DomTreeNodes[I] = C;
-        BBNode = IPDomNode->addChild(C);
-      }
-    }
-
-  // Free temporary memory used to construct idom's
-  IDoms.clear();
-  Info.clear();
-  std::vector<BasicBlock*>().swap(Vertex);
-
-  // Start out with the DFS numbers being invalid.  Let them be computed if
-  // demanded.
-  DFSInfoValid = false;
-}
-
-
-DomTreeNode *PostDominatorTree::getNodeForBlock(BasicBlock *BB) {
-  DomTreeNode *&BBNode = DomTreeNodes[BB];
-  if (BBNode) return BBNode;
-  
-  // Haven't calculated this node yet?  Get or calculate the node for the
-  // immediate postdominator.
-  BasicBlock *IPDom = getIDom(BB);
-  DomTreeNode *IPDomNode = getNodeForBlock(IPDom);
-  
-  // Add a new tree node for this BasicBlock, and link it as a child of
-  // IDomNode
-  DomTreeNode *C = new DomTreeNode(BB, IPDomNode);
-  return DomTreeNodes[BB] = IPDomNode->addChild(C);
-}
-
 //===----------------------------------------------------------------------===//
 //  PostDominanceFrontier Implementation
 //===----------------------------------------------------------------------===//