X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FAnalysis%2FPostDominators.cpp;h=4f9d1d160696f336866748311c1cdbf7642ad835;hb=1c51c6ac13b5e68b099605021784c7f552dcce3c;hp=ee31c36b3e33b932742ca20cb140217f829df26b;hpb=b576c94c15af9a440f69d9d03c2afead7971118c;p=oota-llvm.git

diff --git a/lib/Analysis/PostDominators.cpp b/lib/Analysis/PostDominators.cpp
index ee31c36b3e3..4f9d1d16069 100644
--- a/lib/Analysis/PostDominators.cpp
+++ b/lib/Analysis/PostDominators.cpp
@@ -12,10 +12,11 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/Analysis/PostDominators.h"
-#include "llvm/iTerminators.h"
+#include "llvm/Instructions.h"
 #include "llvm/Support/CFG.h"
-#include "Support/DepthFirstIterator.h"
-#include "Support/SetOperations.h"
+#include "llvm/ADT/DepthFirstIterator.h"
+#include "llvm/ADT/SetOperations.h"
+using namespace llvm;
 
 //===----------------------------------------------------------------------===//
 //  PostDominatorSet Implementation
@@ -39,8 +40,7 @@ bool PostDominatorSet::runOnFunction(Function &F) {
   for (Function::iterator I = F.begin(), E = F.end(); I != E; ++I) {
     Doms[I];  // Initialize to empty
 
-    if (isa<ReturnInst>(I->getTerminator()) ||
-        isa<UnwindInst>(I->getTerminator()))
+    if (succ_begin(I) == succ_end(I))
       Roots.push_back(I);
   }
 
@@ -108,6 +108,43 @@ bool PostDominatorSet::runOnFunction(Function &F) {
 static RegisterAnalysis<ImmediatePostDominators>
 D("postidom", "Immediate Post-Dominators Construction", true);
 
+
+// calcIDoms - Calculate the immediate dominator mapping, given a set of
+// dominators for every basic block.
+void ImmediatePostDominators::calcIDoms(const DominatorSetBase &DS) {
+  // Loop over all of the nodes that have dominators... figuring out the IDOM
+  // for each node...
+  //
+  for (DominatorSet::const_iterator DI = DS.begin(), DEnd = DS.end(); 
+       DI != DEnd; ++DI) {
+    BasicBlock *BB = DI->first;
+    const DominatorSet::DomSetType &Dominators = DI->second;
+    unsigned DomSetSize = Dominators.size();
+    if (DomSetSize == 1) continue;  // Root node... IDom = null
+
+    // Loop over all dominators of this node.  This corresponds to looping over
+    // nodes in the dominator chain, looking for a node whose dominator set is
+    // equal to the current nodes, except that the current node does not exist
+    // in it.  This means that it is one level higher in the dom chain than the
+    // current node, and it is our idom!
+    //
+    DominatorSet::DomSetType::const_iterator I = Dominators.begin();
+    DominatorSet::DomSetType::const_iterator End = Dominators.end();
+    for (; I != End; ++I) {   // Iterate over dominators...
+      // All of our dominators should form a chain, where the number of elements
+      // in the dominator set indicates what level the node is at in the chain.
+      // We want the node immediately above us, so it will have an identical 
+      // dominator set, except that BB will not dominate it... therefore it's
+      // dominator set size will be one less than BB's...
+      //
+      if (DS.getDominators(*I).size() == DomSetSize - 1) {
+	IDoms[BB] = *I;
+	break;
+      }
+    }
+  }
+}
+
 //===----------------------------------------------------------------------===//
 //  PostDominatorTree Implementation
 //===----------------------------------------------------------------------===//
@@ -144,9 +181,8 @@ void PostDominatorTree::calculate(const PostDominatorSet &DS) {
       // be a predecessor in the depth first order that we are iterating through
       // the function.
       //
-      DominatorSet::DomSetType::const_iterator I = Dominators.begin();
-      DominatorSet::DomSetType::const_iterator End = Dominators.end();
-      for (; I != End; ++I) {   // Iterate over dominators...
+      for (DominatorSet::DomSetType::const_iterator I = Dominators.begin(),
+           E = Dominators.end(); I != E; ++I) {  // Iterate over dominators.
         // All of our dominators should form a chain, where the number
         // of elements in the dominator set indicates what level the
         // node is at in the chain.  We want the node immediately
@@ -214,3 +250,4 @@ PostDominanceFrontier::calculate(const PostDominatorTree &DT,
 // stub - a dummy function to make linking work ok.
 void PostDominanceFrontier::stub() {
 }
+