Files in this folder are read by FindMongoDB.cmake script.
We link with MongoDB shell using objects instead of static libs, because:
We require the use of the 'object' mode for release builds because it is the only linking model that works across all of our platforms. We would like to ensure that all of our released artifacts are built with the same known-good-everywhere model.
This is a quote from root SConstruct file in MongoDB repository.
It is possible to build MongoDB shell in the following way:
$ scons mongo --link-model=static
Than we will have produced static libs that we can link with. But in release mode MongoDB SConstruct file do not support static link mode by default. This command will not work:
$ scons mongo --release --link-model=static
We decided to use object link mode even for debug builds, in order to use single mode across all platforms and configurations.
First we build MongoDB shell with the following command:
$ scons mongo -j8 --release
Than we remove compiled mongo and run the same command again to see only final link command:
$ rm build/opt/mongo/mongo
$ scons mongo -j8 --release > release-link-command.txt
And finally we manually copy/paste list of objects to <platform>-release.objects file. Make sure
that they are single-line files.
Almost the same steps we are doing for debug builds:
$ scons mongo -j8 --dbg
$ rm build/debug/mongo/mongo
$ scons mongo -j8 --dbg > debug-link-command.txt
And list of objects is copied to <platform>-debug.objects file.
We found, that on Linux (Ubuntu 14.10), list of debug objects differ from list of release objects only
by two files. File debugallocation.o is linked in debug mode, but not in release.
File debugallocation.o is linked in release mode, but not in debug. Both are located
in third_party/gperftools-2.2/src folder. In any way, we keep separate lists of object files
for both configurations. Still we need to test that objects are the same even across different
versions of Linux.