[cfe-commits] r109243 - /cfe/trunk/include/clang/Analysis/FlowSensitive/DataflowSolver.h

[Ted Kremenek]

Author: kremenek
Date: Fri Jul 23 13:15:17 2010
New Revision: 109243

URL: http://llvm.org/viewvc/llvm-project?rev=109243&view=rev
Log:
Dataflow solver: Don't overrwite the initial value of a block with top unless new values are available.  Patch by Simone Pellegrini!

Modified:
    cfe/trunk/include/clang/Analysis/FlowSensitive/DataflowSolver.h

Modified: cfe/trunk/include/clang/Analysis/FlowSensitive/DataflowSolver.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Analysis/FlowSensitive/DataflowSolver.h?rev=109243&r1=109242&r2=109243&view=diff
==============================================================================
--- cfe/trunk/include/clang/Analysis/FlowSensitive/DataflowSolver.h (original)
+++ cfe/trunk/include/clang/Analysis/FlowSensitive/DataflowSolver.h Fri Jul 23 13:15:17 2010
@@ -231,7 +231,7 @@
 
     EdgeDataMapTy& M = D.getEdgeDataMap();
     bool firstMerge = true;
-
+    bool noEdges = true;
     for (PrevBItr I=ItrTraits::PrevBegin(B),E=ItrTraits::PrevEnd(B); I!=E; ++I){
 
       CFGBlock *PrevBlk = *I;
@@ -243,6 +243,7 @@
         M.find(ItrTraits::PrevEdge(B, PrevBlk));
 
       if (EI != M.end()) {
+        noEdges = false;
         if (firstMerge) {
           firstMerge = false;
           V.copyValues(EI->second);
@@ -252,8 +253,20 @@
       }
     }
 
+    bool isInitialized = true;
+    typename BlockDataMapTy::iterator BI = D.getBlockDataMap().find(B);
+    if(BI == D.getBlockDataMap().end()) {
+      isInitialized = false;
+      BI = D.getBlockDataMap().insert( std::make_pair(B,ValTy()) ).first;
+    }
+    // If no edges have been found, it means this is the first time the solver 
+    // has been called on block B, we copy the initialization values (if any)
+    // as current value for V (which will be used as edge data)
+    if(noEdges && isInitialized) 
+      Merge(V, BI->second);
+
     // Set the data for the block.
-    D.getBlockDataMap()[B].copyValues(V);
+    BI->second.copyValues(V);
   }
 
   /// ProcessBlock - Process the transfer functions for a given block.