Silence all compiler warnings when build

[sl1pkn07]

Description

silence all warnings when build the project

References

when build the project, a tons of warnings like

tmp/makepkg/sl1-mxnet-git/src/incubator-mxnet/include/mxnet/./runtime/ffi_helper.h(41): warning: type qualifier on return type is meaningless

/tmp/makepkg/sl1-mxnet-git/src/incubator-mxnet/include/mxnet/./runtime/ffi_helper.h(41): warning: type qualifier on return type is meaningless

/tmp/makepkg/sl1-mxnet-git/src/incubator-mxnet/include/mxnet/./runtime/ffi_helper.h(57): warning: type qualifier on return type is meaningless

/tmp/makepkg/sl1-mxnet-git/src/incubator-mxnet/include/mxnet/./runtime/ffi_helper.h(57): warning: type qualifier on return type is meaningless

/tmp/makepkg/sl1-mxnet-git/src/incubator-mxnet/include/mxnet/./runtime/ffi_helper.h(77): warning: extra ";" ignored

/tmp/makepkg/sl1-mxnet-git/src/incubator-mxnet/include/mxnet/./runtime/ffi_helper.h(89): warning: type qualifier on return type is meaningless

/tmp/makepkg/sl1-mxnet-git/src/incubator-mxnet/include/mxnet/./runtime/ffi_helper.h(89): warning: type qualifier on return type is meaningless

/tmp/makepkg/sl1-mxnet-git/src/incubator-mxnet/include/mxnet/./runtime/ffi_helper.h(99): warning: extra ";" ignored

/tmp/makepkg/sl1-mxnet-git/src/incubator-mxnet/include/mxnet/./node/container.h(45): warning: type qualifier on return type is meaningless

/tmp/makepkg/sl1-mxnet-git/src/incubator-mxnet/include/mxnet/./node/container.h(45): warning: type qualifier on return type is meaningless

/tmp/makepkg/sl1-mxnet-git/src/incubator-mxnet/include/mxnet/./ir/expr.h(43): warning: type qualifier on return type is meaningless

/tmp/makepkg/sl1-mxnet-git/src/incubator-mxnet/include/mxnet/./ir/expr.h(43): warning: type qualifier on return type is meaningless

/tmp/makepkg/sl1-mxnet-git/src/incubator-mxnet/include/mxnet/./ir/expr.h(94): warning: type qualifier on return type is meaningless

/tmp/makepkg/sl1-mxnet-git/src/incubator-mxnet/include/mxnet/./ir/expr.h(94): warning: type qualifier on return type is meaningless

/tmp/makepkg/sl1-mxnet-git/src/incubator-mxnet/include/mxnet/./ir/expr.h(144): warning: type qualifier on return type is meaningless

/tmp/makepkg/sl1-mxnet-git/src/incubator-mxnet/include/mxnet/./ir/expr.h(144): warning: type qualifier on return type is meaningless

/tmp/makepkg/sl1-mxnet-git/src/incubator-mxnet/include/mxnet/./ir/expr.h(189): warning: type qualifier on return type is meaningless

/tmp/makepkg/sl1-mxnet-git/src/incubator-mxnet/include/mxnet/./ir/expr.h(189): warning: type qualifier on return type is meaningless

/tmp/makepkg/sl1-mxnet-git/src/incubator-mxnet/include/mxnet/runtime/container.h(176): warning: type qualifier on return type is meaningless

/tmp/makepkg/sl1-mxnet-git/src/incubator-mxnet/include/mxnet/runtime/container.h(176): warning: type qualifier on return type is meaningless

/tmp/makepkg/sl1-mxnet-git/src/incubator-mxnet/include/mxnet/runtime/container.h(276): warning: extra ";" ignored

(Done in #17718)

and others like

[ 64%] Building CUDA object CMakeFiles/mxnet_static.dir/src/common/utils.cu.o
/tmp/makepkg/sl1-mxnet-git/src/incubator-mxnet/include/mshadow/./base.h(842): warning: integer conversion resulted in a change of sign

In file included from /tmp/makepkg/sl1-mxnet-git/src/incubator-mxnet/src/storage/../profiler/storage_profiler.h:25,
                 from /tmp/makepkg/sl1-mxnet-git/src/incubator-mxnet/src/storage/storage.cc:32:
In member function 'void mxnet::profiler::static_string<string_size>::set(const char*) [with long unsigned int string_size = 128]',
    inlined from 'mxnet::profiler::ProfileCounter::ProfileCounterStat::ProfileCounterStat(const char*, uint64_t)' at /tmp/makepkg/sl1-mxnet-git/src/incubator-mxnet/src/storage/../profiler/./profiler.h:636:16,
    inlined from 'static std::unique_ptr<typename std::enable_if<std::is_base_of<mxnet::profiler::ProfileStat, StatType>::value, StatType>::type> mxnet::profiler::Profiler::CreateProfileStat(Args ...) [with StatType = mxnet::profiler::ProfileCounter::ProfileCounterStat; Args = {const char*, long unsigned int}]' at /tmp/makepkg/sl1-mxnet-git/src/incubator-mxnet/src/storage/../profiler/./profiler.h:419:38,
    inlined from 'void mxnet::profiler::Profiler::AddNewProfileStat(SetExtraInfoFunction, Args ...) [with StatType = mxnet::profiler::ProfileCounter::ProfileCounterStat; SetExtraInfoFunction = mxnet::profiler::ProfileCounter::SendStat(uint64_t)::<lambda(mxnet::profiler::ProfileCounter::ProfileCounterStat*)>; Args = {const char*, long unsigned int}]' at /tmp/makepkg/sl1-mxnet-git/src/incubator-mxnet/src/storage/../profiler/./profiler.h:320:33,
    inlined from 'void mxnet::profiler::ProfileCounter::SendStat(uint64_t)' at /tmp/makepkg/sl1-mxnet-git/src/incubator-mxnet/src/storage/../profiler/./profiler.h:673:59:
/tmp/makepkg/sl1-mxnet-git/src/incubator-mxnet/src/storage/../profiler/./profiler.h:57:12: warning: 'char* strncpy(char*, const char*, size_t)' output may be truncated copying 127 bytes from a string of length 127 [-Wstringop-truncation]
     strncpy(&string_[0], s, string_size - 1);
     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In member function 'void mxnet::profiler::static_string<string_size>::set(const char*) [with long unsigned int string_size = 128]',
    inlined from 'mxnet::profiler::ProfileCounter::SendStat(uint64_t)::<lambda(mxnet::profiler::ProfileCounter::ProfileCounterStat*)>' at /tmp/makepkg/sl1-mxnet-git/src/incubator-mxnet/src/storage/../profiler/./profiler.h:674:83,
    inlined from 'void mxnet::profiler::Profiler::AddNewProfileStat(SetExtraInfoFunction, Args ...) [with StatType = mxnet::profiler::ProfileCounter::ProfileCounterStat; SetExtraInfoFunction = mxnet::profiler::ProfileCounter::SendStat(uint64_t)::<lambda(mxnet::profiler::ProfileCounter::ProfileCounterStat*)>; Args = {const char*, long unsigned int}]' at /tmp/makepkg/sl1-mxnet-git/src/incubator-mxnet/src/storage/../profiler/./profiler.h:321:30,
    inlined from 'void mxnet::profiler::ProfileCounter::SendStat(uint64_t)' at /tmp/makepkg/sl1-mxnet-git/src/incubator-mxnet/src/storage/../profiler/./profiler.h:673:59:
/tmp/makepkg/sl1-mxnet-git/src/incubator-mxnet/src/storage/../profiler/./profiler.h:57:12: warning: 'char* strncpy(char*, const char*, size_t)' output may be truncated copying 127 bytes from a string of length 127 [-Wstringop-truncation]
     strncpy(&string_[0], s, string_size - 1);
     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

the full log:
full_log.txt

this is not considered a bug, because at the moment, the build process finished OK. but is good silence this warnings wich fill with spam the output

greetings

[leezu]

@hzfan could you fix the warnings in ffi that you introduced.

CI already tests with -WError to prevent introducing more problems, but that test needs to be changed to run with a newer compiler toolchain.

[hzfan]

I created a pr #17718 to fix the warnings introduced by FFI.

Any ways to detect these warnings as errors? I tried to build with -DCMAKE_BUILD_TYPE=Debug, which I think implies -WError (not verified), but they remain warnings. I think it would be great to have such tools, which allow developers to check warnings before PR gets merged.

[leezu]

As of #17645, -DCMAKE_BUILD_TYPE="RelWithDebInfo" will run with -WError (and be tested on CI).
-DCMAKE_BUILD_TYPE="RelWithDebInfo" is thus similar to make DEV=1.

CI may have used an older compiler without the respective warnings for the pipeline running with -WError and thus passed. I'll look into that after #17645 is merged.

[sl1pkn07]

build_log_20200301_10a12d59f6.txt

fixed ones, introduce others

greetings

[leezu]

See #17752 for fixing the CPU build.
There are still remaining warnings affecting the cuda build