Use hidden visibility to reduce the sizes of some .o files.  This chops 60K off a release llvm-dis.

llvm-svn: 28969
diff --git a/llvm/lib/VMCore/Verifier.cpp b/llvm/lib/VMCore/Verifier.cpp
index 8a4cf2c..d07345e 100644
--- a/llvm/lib/VMCore/Verifier.cpp
+++ b/llvm/lib/VMCore/Verifier.cpp
@@ -57,6 +57,7 @@
 #include "llvm/Support/InstVisitor.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/ADT/STLExtras.h"
+#include "llvm/Support/Visibility.h"
 #include <algorithm>
 #include <iostream>
 #include <sstream>
@@ -65,7 +66,8 @@
 
 namespace {  // Anonymous namespace for class
 
-  struct Verifier : public FunctionPass, InstVisitor<Verifier> {
+  struct VISIBILITY_HIDDEN
+     Verifier : public FunctionPass, InstVisitor<Verifier> {
     bool Broken;          // Is this module found to be broken?
     bool RealPass;        // Are we not being run by a PassManager?
     VerifierFailureAction action;