Index: include/llvm/IR/Function.h
===================================================================
--- include/llvm/IR/Function.h
+++ include/llvm/IR/Function.h
@@ -555,6 +555,9 @@
              bool ShouldPreserveUseListOrder = false,
              bool IsForDebug = false) const;
 
+  /// Dump the function as it is the only defined function in module.
+  void dumpAsSingleDefine();
+
   /// viewCFG - This function is meant for use from the debugger.  You can just
   /// say 'call F->viewCFG()' and a ghostview window should pop up from the
   /// program, displaying the CFG of the current function with the code for each
Index: lib/IR/Function.cpp
===================================================================
--- lib/IR/Function.cpp
+++ lib/IR/Function.cpp
@@ -1005,3 +1005,41 @@
       }
   return None;
 }
+
+void Function::dumpAsSingleDefine()
+{
+  typedef std::vector<BasicBlock*> BlockList;
+  typedef std::pair<BlockList*, GlobalValue::LinkageTypes> FuncInfo;
+  typedef std::map<Function*, FuncInfo> FuncMap;
+  FuncMap funcList;
+  // Temporarily change all defined functions to be declaration
+  // except for this one.
+  Module* M = getParent();
+  for (Function &F : *M)
+    if (!F.isDeclaration() && &F != this) {
+      BlockList* blockList = new BlockList;
+      Function::BasicBlockListType &oldBlocks = F.getBasicBlockList();
+      while (!oldBlocks.empty()) {
+        blockList->push_back(&oldBlocks.back());
+        oldBlocks.remove(oldBlocks.back());
+      }
+      funcList[&F]= std::make_pair(blockList, F.getLinkage());
+      F.setLinkage(ExternalLinkage);
+    }
+
+  M->dump();
+
+  // Restore everything back.
+  for (auto it : funcList) {
+    Function* F = it.first;
+    BlockList* list = it.second.first;
+    GlobalValue::LinkageTypes LT = it.second.second;
+    Function::BasicBlockListType &oldBlocks = F->getBasicBlockList();
+    while(!list->empty()) {
+      oldBlocks.push_back(list->back());
+      list->pop_back();
+    }
+    F->setLinkage(LT);
+  }
+}
+