Test with coverage output, publish gcov on Azure pipelines

[qiluo-msft]

No description provided.

[kcudnik]

This seems much simpler than this preposition: https://github.com/Azure/sonic-swss/pull/1737/files
Will this change also include coverage during vstests run or this is only for local unit tests ?

[kcudnik]

should we consider disabling optimization when performing code coverage: https://gcc.gnu.org/onlinedocs/gcc/Gcov-and-Optimization.html

[kcudnik]

should we consider disabling optimization when performing code coverage: https://gcc.gnu.org/onlinedocs/gcc/Gcov-and-Optimization.html

seems like CODE_COVERAGE override that by default:
224 CODE_COVERAGE_CFLAGS = -O0 -g -fprofile-arcs -ftest-coverage
225 CODE_COVERAGE_CPPFLAGS = -DNDEBUG
226 CODE_COVERAGE_CXXFLAGS = -O0 -g -fprofile-arcs -ftest-coverage

[kcudnik]

@qiluo-msft in your build you get the same error:
https://dev.azure.com/mssonic/build/_build/results?buildId=26869&view=logs&j=a5b8631f-d2a8-5bf4-c5b7-ed5dd46e146c&t=93567928-e4d4-5802-f979-ee59d6645988&l=313
you need to install autoconf-archive package additionally, and also CODE_COVERAGE_CXXFLAGS even passed at last are overrided by CXXFLAGS which by default are "-g -O2" so CODE_COVERAGE_CXXFLAGS with "-O0" is ignored
command needed to compile this would be:

make CFLAGS="" CXXFLAGS=""

to disable optimization

[kcudnik]

maybe gcovr will need extra parameter "--exclude-throw-branches" explanation: gcovr/gcovr#283
for out current code every SWSS_LOG_ENTER() will show untaken branch (throw) that is not taken

this is due to compiler generating possible exception handling in the constructor and seems like gcov is catching that as branch not executed

Also for example compiling sonic-sairedis with -O0, will also need probably swss-common compiled with -O0, since there could be artefacts, for example sizeof(std::string) is different when compiled in -O2 and -O0 since it's contain more debug info and this could lead to some weird exceptions and crashes in code

correction upper claim is actually mitigated by CODE_COVERAGE_CPPFLAGS which contains "-DNDEBUG" which prevents any issues, just code is compiled with -O0 but as production and not debug code

[qiluo-msft]

/azpw run

[mssonicbld]

/AzurePipelines run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).