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GCC warnings in slice-generated code

joshmoorejoshmoore GermanyMember Josh MooreOrganization: Glencoe Software, Inc.Project: OME, http://openmicroscopy.org
In an effort to remove all the compiler warnings for OMERO.cpp, it was necessary to disable several types of GCC warnings for the code generated by slice2cpp:
  • -Wno-switch-default
  • -Wno-redundant-decls
  • -Wno-overloaded-virtual
  • -Wno-old-style-cast
  • -Wno-deprecated-declarations

This was done on the one hand by using cmake's set_source_files_properties to disable the warnings during the compilation of the generated .cpp files themselves and on the other by intoducing a IceNoWarnPush header which must be included before all includes of generated header files.

Support either in slice2cpp or via compiler flags would be appreciated to help reduce these warnings. A sampling of the errors is below.

Cheers,
~Josh
/opt/ome1/components/tools/OmeroCpp/cppbuild/components/tools/OmeroCpp/gen/omero/api/Gateway.cpp: In member function ‘Ice::DispatchStatus omero::api::Gateway::___keepAlive(IceInternal::Incoming&, const Ice::Current&)’:
/opt/ome1/components/tools/OmeroCpp/cppbuild/components/tools/OmeroCpp/gen/omero/api/Gateway.cpp:9852:28: error: ‘virtual void omero::api::Gateway::keepAlive(const Ice::Current&)’ is deprecated (declared at /opt/ome1/components/tools/OmeroCpp/cppbuild/components/tools/OmeroCpp/gen/omero/api/Gateway.h:5474) [-Werror=deprecated-declarations]
         keepAlive(__current);
In file included from /opt/Ice-3.5.1/include/IceUtil/ThreadException.h:14:0,
                 from /opt/Ice-3.5.1/include/IceUtil/Lock.h:14,
                 from /opt/Ice-3.5.1/include/IceUtil/Mutex.h:14,
                 from /opt/Ice-3.5.1/include/Ice/Proxy.h:14,
                 from /opt/ome1/components/tools/OmeroCpp/cppbuild/components/tools/OmeroCpp/gen/omero/RTypes.h:29,
                 from /opt/ome1/components/tools/OmeroCpp/cppbuild/components/tools/OmeroCpp/gen/omero/RTypes.cpp:21:
/opt/Ice-3.5.1/include/IceUtil/Time.h: In member function ‘double IceUtil::Time::operator/(const IceUtil::Time&) const’:
/opt/Ice-3.5.1/include/IceUtil/Time.h:117:24: error: use of old-style cast [-Werror=old-style-cast]
         return (double)_usec / (double)rhs._usec;
                        ^
/opt/Ice-3.5.1/include/IceUtil/Time.h:117:44: error: use of old-style cast [-Werror=old-style-cast]
         return (double)_usec / (double)rhs._usec;
In file included from /opt/Ice-3.5.1/include/Ice/BasicStream.h:14:0,
                 from /opt/Ice-3.5.1/include/Ice/OutgoingAsync.h:24,
                 from /opt/Ice-3.5.1/include/Ice/Proxy.h:25,
                 from /opt/ome1/components/tools/OmeroCpp/cppbuild/components/tools/OmeroCpp/gen/omero/RTypes.h:29,
                 from /opt/ome1/components/tools/OmeroCpp/cppbuild/components/tools/OmeroCpp/gen/omero/RTypes.cpp:21:
/opt/Ice-3.5.1/include/Ice/Object.h:124:18: error: ‘virtual void Ice::Object::__readImpl(const InputStreamPtr&)’ was hidden [-Werror=overloaded-virtual]
     virtual void __readImpl(const InputStreamPtr&);
                  ^
In file included from /opt/ome1/components/tools/OmeroCpp/cppbuild/components/tools/OmeroCpp/gen/omero/RTypes.cpp:21:0:
/opt/ome1/components/tools/OmeroCpp/cppbuild/components/tools/OmeroCpp/gen/omero/RTypes.h:4084:18: error:   by ‘virtual void omero::RType::__readImpl(IceInternal::BasicStream*)’ [-Werror=overloaded-virtual]
     virtual void __readImpl(::IceInternal::BasicStream*);
                  ^
In file included from /opt/Ice-3.5.1/include/Ice/BasicStream.h:16:0,
                 from /opt/Ice-3.5.1/include/Ice/OutgoingAsync.h:24,
                 from /opt/Ice-3.5.1/include/Ice/Proxy.h:25,
                 from /opt/ome1/components/tools/OmeroCpp/cppbuild/components/tools/OmeroCpp/gen/omero/RTypes.h:29,
                 from /opt/ome1/components/tools/OmeroCpp/cppbuild/components/tools/OmeroCpp/gen/omero/RTypes.cpp:21:
/opt/Ice-3.5.1/include/Ice/ObjectFactoryF.h:59:29: error: previous declaration of ‘Ice::LocalObject* Ice::upCast(Ice::ObjectFactory*)’ [-Werror=redundant-decls]
 ICE_API ::Ice::LocalObject* upCast(::Ice::ObjectFactory*);
                             ^
/opt/ome1/components/tools/OmeroCpp/cppbuild/components/tools/OmeroCpp/gen/omero/RTypes.cpp: In member function ‘virtual Ice::DispatchStatus omero::RMap::__dispatch(IceInternal::Incoming&, const Ice::Current&)’:
/opt/ome1/components/tools/OmeroCpp/cppbuild/components/tools/OmeroCpp/gen/omero/RTypes.cpp:5746:11: error: switch missing default case [-Werror=switch-default]
     switch(r.first - __omero__RMap_all)
           ^

Comments

  • bernardbernard Jupiter, FLAdministrators, ZeroC Staff Bernard NormierOrganization: ZeroC, Inc.Project: Ice ZeroC Staff
    Hi Josh,

    Thank you for this report. We will definitely fix some of these, for example, the C-style in a header is clearly an oversight.

    With GCC, we currently use -Wall -Werror when building Ice (+ tests and demos). Which flag(s) do you use to get these additional warnings?

    Best regards,
    Bernard
  • rleighrleigh Member Roger LeighOrganization: University of DundeeProject: OMERO (Open Microscopy Environment)
    Our currently used set of flags is:
    -Wall
          -Wcast-align
          -Wcast-qual
          -Wctor-dtor-privacy
          -Wextra
          -Wformat=2
          -Wimplicit-atomic-properties
          -Wmissing-declarations
          -Wnon-virtual-dtor
          -Wold-style-cast
          -Woverlength-strings
          -Woverloaded-virtual
          -Wredundant-decls
          -Wreorder
          -Wswitch-default
          -Wunused-variable
          -Wwrite-strings
          -fstrict-aliasing
    

    The following are also used routinely, but can be disabled with cmake (due to the larger number of warnings in third-party headers):
    -Wconversion
          -Wdocumentation
          -Wfloat-equal
          -Wmissing-prototypes
          -Wunreachable-code
    

    The main GCC-specific version difference we encounter is on "switch(enum)" which triggers -Wswitch-default if it lacks a default case, but isn't needed due to covering all available enumerations in existing cases. If you add a default case, you then get unreachable code warnings. For this specific case we wrap the function contining the switch with
    #ifdef __GNUC__
    #  pragma GCC diagnostic push
    #  pragma GCC diagnostic ignored "-Wswitch-default"
    #endif
    
    <function>
    
    #ifdef __GNUC__
    #  pragma GCC diagnostic pop
    #endif
    

    which allows other (non-enum) switch statements to benefit from -Wswitch-default checking. Other than this exception to the rule, we make sure our code is clean for all of the above warnings. If the slice2cpp-generated code could also be made clean, this would be greatly beneficial for ourselves and all other users who build with strict warnings.

    Kind regards,
    Roger Leigh
  • rleighrleigh Member Roger LeighOrganization: University of DundeeProject: OMERO (Open Microscopy Environment)
    Compiler checks

    Just FYI, this is our current use of these flags:

    https://github.com/openmicroscopy/bioformats/blob/develop/cpp/cmake/CompilerChecks.cmake
  • rleighrleigh Member Roger LeighOrganization: University of DundeeProject: OMERO (Open Microscopy Environment)
    MSVC compiler flags

    I should also note that for Windows builds, having the generated Ice headers generate zero warnings with cl /W3 and /W4 would also be highly desirable.
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