check in reaching defs analysis

diff --git a/Robust/src/Analysis/ReachingDefs.java b/Robust/src/Analysis/ReachingDefs.java
new file mode 100644 (file)
index 0000000..56095d0
--- /dev/null
+++ b/Robust/src/Analysis/ReachingDefs.java
@@ -0,0 +1,54 @@
+package Analysis;
+
+import IR.Flat.*;
+import java.util.HashSet;
+import java.util.Set;
+import java.util.Iterator;
+import java.util.Hashtable;
+
+public class ReachingDefs {
+  /* This methods takes in a FlatMethod and returns a map from a
+   * FlatNode to the set of live temps for that FlatNode.*/
+
+  public static Hashtable<FlatNode, Hashtable<TempDescriptor, Set<FlatNode>>> computeReachingDefs(FlatMethod fm) {
+    Hashtable<FlatNode, Hashtable<TempDescriptor, Set<FlatNode>>> nodetotemps=new Hashtable<FlatNode, Hashtable<TempDescriptor,Set<FlatNode>>>();
+    
+    Set<FlatNode> toprocess=fm.getNodeSet();
+    
+    while(!toprocess.isEmpty()) {
+      FlatNode fn=toprocess.iterator().next();
+      toprocess.remove(fn);
+      
+      Hashtable<TempDescriptor, Set<FlatNode>> tempset=new Hashtable<TempDescriptor, Set<FlatNode>>();
+
+      for(int i=0; i<fn.numPrev(); i++) {
+       FlatNode fnprev=fn.getPrev(i);
+       if (nodetotemps.containsKey(fnprev)) {
+         Hashtable<TempDescriptor,Set<FlatNode>> prevtable=nodetotemps.get(fnprev);
+         for(Iterator<TempDescriptor> tmpit=prevtable.keySet().iterator();tmpit.hasNext();) {
+           TempDescriptor tmp=tmpit.next();
+           if (!tempset.containsKey(tmp))
+             tempset.put(tmp, new HashSet<FlatNode>());
+           tempset.get(tmp).addAll(prevtable.get(tmp));
+         }
+       }
+      }
+      
+      TempDescriptor writes[]=fn.writesTemps();
+      for(int i=0;i<writes.length;i++) {
+       HashSet<FlatNode> s=new HashSet<FlatNode>();
+       s.add(fn);
+       tempset.put(writes[i],s);
+      }
+
+      if (!nodetotemps.containsKey(fn)||
+          !nodetotemps.get(fn).equals(tempset)) {
+       nodetotemps.put(fn, tempset);
+       for(int i=0; i<fn.numNext(); i++)
+         toprocess.add(fn.getNext(i));
+      }
+    }
+    return nodetotemps;
+  }
+  
+}
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