Added -view-callgraph module pass.

-dot-callgraph similarly follows a standard module pass pattern.

Patch by Speziale Ettore!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@172220 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Analysis/CallPrinter.h

@@ -0,0 +1,27 @@
+//===-- CallPrinter.h - Call graph printer external interface ----*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines external functions that can be called to explicitly
+// instantiate the call graph printer.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_ANALYSIS_CALLPRINTER_H
+#define LLVM_ANALYSIS_CALLPRINTER_H
+
+namespace llvm {
+
+  class ModulePass;
+
+  ModulePass *createCallGraphViewerPass();
+  ModulePass *createCallGraphPrinterPass();
+
+} // end namespace llvm
+
+#endif