Are there some better ways to address warnings when compiling protocol buffer generated source file?

You can hack the source of the protoc compiler to have it inject the pragmas into the generated files automatically.

In src/google/protobuf/compiler/cpp/cpp_file.cc in GenerateHeader(io::Printer* printer) around line 94, change the first printer->Print call to:

  // Generate top of header.
  printer->Print(
    "// Generated by the protocol buffer compiler.  DO NOT EDIT!\n"
    "// source: $filename$\n"
    "\n"
    "#ifndef PROTOBUF_$filename_identifier$__INCLUDED\n"
    "#define PROTOBUF_$filename_identifier$__INCLUDED\n"
    "\n"
    "#ifdef _MSC_VER\n"
    "#  pragma warning(push)\n"
    "#  pragma warning(disable: 4127 4244 4267)\n"
    "#endif\n"
    "\n"
    "#include <string>\n"
    "\n",
    "filename", file_->name(),
    "filename_identifier", filename_identifier);

Then at the end of the same function at around line 294, change the last printer->Print call to:

  printer->Print(
    "#ifdef _MSC_VER\n"
    "#  pragma warning(pop)\n"
    "#endif\n"
    "\n"
    "#endif  // PROTOBUF_$filename_identifier$__INCLUDED\n",
    "filename_identifier", filename_identifier);

Now you just need to compile the protoc target and run the new protoc.exe to have the pragmas in the generated headers.

A simple approach is to use a wrapper header for including the generated protobuf headers:

#ifndef MESSAGES_WRAPPER_H
#define MESSAGES_WRAPPER_H

#ifdef _MSC_VER
  #pragma warning(push)
  #pragma warning(disable: 4018 4100 4267)
#endif

#include "messages.pb.h"

#ifdef _MSC_VER
  #pragma warning(pop)
#endif

#endif // MESSAGES_WRAPPER_H