Fix Clang-tidy modernize-use-nullptr warnings in headers and generated files; other minor cleanups.

By Eugene Zelenko!

Differential Revision: http://reviews.llvm.org/D13187

llvm-svn: 248828
diff --git a/clang/lib/CodeGen/CodeGenModule.h b/clang/lib/CodeGen/CodeGenModule.h
index 5f40d41..b1071a4 100644
--- a/clang/lib/CodeGen/CodeGenModule.h
+++ b/clang/lib/CodeGen/CodeGenModule.h
@@ -715,7 +715,7 @@
 
   /// Return the address of the given function. If Ty is non-null, then this
   /// function will use the specified type if it has to create it.
-  llvm::Constant *GetAddrOfFunction(GlobalDecl GD, llvm::Type *Ty = 0,
+  llvm::Constant *GetAddrOfFunction(GlobalDecl GD, llvm::Type *Ty = nullptr,
                                     bool ForVTable = false,
                                     bool DontDefer = false,
                                     bool IsForDefinition = false);
@@ -1184,7 +1184,7 @@
 
   // FIXME: Hardcoding priority here is gross.
   void AddGlobalCtor(llvm::Function *Ctor, int Priority = 65535,
-                     llvm::Constant *AssociatedData = 0);
+                     llvm::Constant *AssociatedData = nullptr);
   void AddGlobalDtor(llvm::Function *Dtor, int Priority = 65535);
 
   /// Generates a global array of functions and priorities using the given list
@@ -1251,4 +1251,4 @@
 }  // end namespace CodeGen
 }  // end namespace clang
 
-#endif
+#endif // LLVM_CLANG_LIB_CODEGEN_CODEGENMODULE_H