Small PostDominatorTree improvements

 * Do not SEGFAULT if tree entryNode() is NULL
 * Print function names in dotty printer

llvm-svn: 90130

2 files changed, 13 insertions, 4 deletions

diff --git a/llvm/include/llvm/Analysis/PostDominators.h b/llvm/include/llvm/Analysis/PostDominators.h
index 42a16e74a24..ea14b2da9ce 100644
--- a/llvm/include/llvm/Analysis/PostDominators.h
+++ b/llvm/include/llvm/Analysis/PostDominators.h
@@ -81,7 +81,10 @@ template <> struct GraphTraits<PostDominatorTree*>
   }
 
   static nodes_iterator nodes_begin(PostDominatorTree *N) {
-    return df_begin(getEntryNode(N));
+    if (getEntryNode(N))
+      return df_begin(getEntryNode(N));
+    else
+      return df_end(getEntryNode(N));
   }
 
   static nodes_iterator nodes_end(PostDominatorTree *N) {
diff --git a/llvm/lib/Analysis/DomPrinter.cpp b/llvm/lib/Analysis/DomPrinter.cpp
index f1b44d0356e..ebfba7ef0f6 100644
--- a/llvm/lib/Analysis/DomPrinter.cpp
+++ b/llvm/lib/Analysis/DomPrinter.cpp
@@ -85,9 +85,11 @@ struct GenericGraphViewer : public FunctionPass {
 
   virtual bool runOnFunction(Function &F) {
     Analysis *Graph;
-
+    std::string Title, GraphName;
     Graph = &getAnalysis<Analysis>();
-    ViewGraph(Graph, Name, OnlyBBS);
+    GraphName = DOTGraphTraits<Analysis*>::getGraphName(Graph);
+    Title = GraphName + " for '" + F.getNameStr() + "' function";
+    ViewGraph(Graph, Name, OnlyBBS, Title);
 
     return false;
   }
@@ -163,8 +165,12 @@ struct GenericGraphPrinter : public FunctionPass {
     raw_fd_ostream File(Filename.c_str(), ErrorInfo);
     Graph = &getAnalysis<Analysis>();
 
+    std::string Title, GraphName;
+    GraphName = DOTGraphTraits<Analysis*>::getGraphName(Graph);
+    Title = GraphName + " for '" + F.getNameStr() + "' function";
+
     if (ErrorInfo.empty())
-      WriteGraph(File, Graph, OnlyBBS);
+      WriteGraph(File, Graph, OnlyBBS, Name, Title);
     else
       errs() << "  error opening file for writing!";
     errs() << "\n";