uninative, older distros and libstdc++ [2.2 uninative issue]

We've had a lot of success with uninative but in the 2.2-rc2 build which I ran last night on two different autobuilders, we saw two different failures:

https://bugzilla.yoctoproject.org/show_bug.cgi?id=10441

On a system compiling source-highlight-native with gcc 4.9 where boost- native was built on a gcc 5 system, we see one error. On a system compiling source-highlight-native with gcc 4.8 where boost-native was built on a gcc 4.9 system, we see a different error.

The trouble is that libboost_regex.so in these cases wants the newer libstdc++ but at link time of executable, it can only see the host system and hence can't see newer symbols like std::runtime_error::runtime_error(char const*) or std::__throw_out_of_range_fmt(char const*, ...).

I have done a lot of experimentation and the only way I can see of possibly making this work is to add -Wl,--unresolved-symbols=ignore-in- shared-libs to BUILD_LDFLAGS for source-highlight *and* ensure any native binaries get tweaked to use our own uninative loader before they're run. The former is horrible and the latter bit is hard.

Another option would be to have multiple uninative feeds based on gcc version rather than a single uninative one.

This close to release, I'm reluctant to poke this too much. We don't have many components that using C++, source-highlight is a comparatively new one which isn't in our default configuration for now. I'm therefore tempted to release note and look at this in 2.3.

Opinions? Other ideas?

Cheers,

Richard

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Quoted 35 lines

On Oct 16, 2016, at 5:59 AM, Richard Purdie <richard.purdie@linuxfo undation.org> wrote:

We've had a lot of success with uninative but in the 2.2-rc2 build which I ran last night on two different autobuilders, we saw two different failures:

https://bugzilla.yoctoproject.org/show_bug.cgi?id=10441

On a system compiling source-highlight-native with gcc 4.9 where boost-
native was built on a gcc 5 system, we see one error. On a system compiling source-highlight-native with gcc 4.8 where boost-native was
built on a gcc 4.9 system, we see a different error.

The trouble is that libboost_regex.so in these cases wants the newer
libstdc++ but at link time of executable, it can only see the host system and hence can't see newer symbols like std::runtime_error::runtime_error(char const*) or std::__throw_out_of_range_fmt(char const*, ...).

I have done a lot of experimentation and the only way I can see of possibly making this work is to add -Wl,--unresolved- symbols=ignore-in-
shared-libs to BUILD_LDFLAGS for source-highlight *and* ensure any native binaries get tweaked to use our own uninative loader before they're run. The former is horrible and the latter bit is hard.

Another option would be to have multiple uninative feeds based on gcc
version rather than a single uninative one.

Quoted 8 lines

This close to release, I'm reluctant to poke this too much. We don't
have many components that using C++, source-highlight is a comparatively new one which isn't in our default configuration for now.
I'm therefore tempted to release note and look at this in 2.3.

Opinions? Other ideas?

I think it could be related to ABI versions, may be while compiling libstdc++ with gcc5 should enable --disable-libstdcxx-dual-abi --with-default-libstdcxx-abi=c++98 for checks and see if it works its also not best solution since thats now the default but it will ensure that this is the problem we are running into. Then second option
would be then to use --enable-libstdcxx-dual-abi --with-default-libstdcxx-abi=c++98

this combination might be better of the two. of course this would then
need testing it with gcc5+ as well.

Quoted 52 lines · Khem Raj

Quoted 35 lines

On Oct 16, 2016, at 5:59 AM, Richard Purdie <richard.purdie@linuxfo undation.org> wrote:

We've had a lot of success with uninative but in the 2.2-rc2 build which I ran last night on two different autobuilders, we saw two different failures:

https://bugzilla.yoctoproject.org/show_bug.cgi?id=10441

On a system compiling source-highlight-native with gcc 4.9 where boost-
native was built on a gcc 5 system, we see one error. On a system compiling source-highlight-native with gcc 4.8 where boost-native was
built on a gcc 4.9 system, we see a different error.

The trouble is that libboost_regex.so in these cases wants the newer
libstdc++ but at link time of executable, it can only see the host system and hence can't see newer symbols like std::runtime_error::runtime_error(char const*) or std::__throw_out_of_range_fmt(char const*, ...).

I have done a lot of experimentation and the only way I can see of possibly making this work is to add -Wl,--unresolved- symbols=ignore-in-
shared-libs to BUILD_LDFLAGS for source-highlight *and* ensure any native binaries get tweaked to use our own uninative loader before they're run. The former is horrible and the latter bit is hard.

Another option would be to have multiple uninative feeds based on gcc
version rather than a single uninative one.

Quoted 8 lines

This close to release, I'm reluctant to poke this too much. We don't
have many components that using C++, source-highlight is a comparatively new one which isn't in our default configuration for now.
I'm therefore tempted to release note and look at this in 2.3.

Opinions? Other ideas?

I think it could be related to ABI versions, may be while compiling libstdc++ with gcc5 should enable --disable-libstdcxx-dual-abi --with-default-libstdcxx-abi=c++98 for checks and see if it works its also not best solution since thats now the default but it will ensure that this is the problem we are running into. Then second option
would be then to use --enable-libstdcxx-dual-abi --with-default-libstdcxx-abi=c++98

Quoted 3 lines

this combination might be better of the two. of course this would then
need testing it with gcc5+ as well.

We're already effectively doing this. The trouble is the libraries are not forward compatible. For example, if you build boost-native for gcc5, then use it on a machine which has gcc 4.9 to link into source- highlight-native, it looks for the gcc5 symbols used by libboost which aren't in the host system's libstdc++. If you try and make it link against the uninative libstdc++ (for which the dev symlinks are missing), you get all kinds of other weird errors since the headers are from gcc 4.9 but the lib from gcc5.

I'm not sure there is a way to make it work properly in all cases for C++ :(. If there is I've failed to find it so far.

The dual ABI is already enabled and defaulting to something old, but that doesn't make it forwards compatible.

Cheers,

Richard