I am working on a huge C++ project, targeting many platforms with several configurations for each platform.
Because of the long compilation time, build the entire project on every platform to test if a change compile successfully, isn't an option.
What I usually do, is compile the single cpp modules I modified on different combination of platform/configuration. I'd like to automate this process, either using a script, a VS extension, whatever, I am open to evaluate different options.
What I need exactly is taking a list of cpp files and compile each file, for each platform and each configuration (basically iterating through all combination of the configuration manager).
Is this possible? any good suggestion on how to approach the problem?
EDIT:
I am aware that this is way far to be a perfect solution, and will spot only a subset of errors. I will still have to face linking errors, compiler errors on other cpp units depended on a modified header, and so on..
I also, don't have any chance to modify the current build system, or project generation.
I am mostly interested in a local solution, to reduce the amount of possible issues and facing the huge building time process.
2 Answers
Answers 1
I would suggest that you "simply" write a script to do this (using Python for instance, which is very powerful for this kind of this)
You could:
- Parse the .sln file to extract the list of configurations, platforms (
GlobalSection(SolutionConfigurationPlatforms)entry) and projects (Projectentry) - If needed, you can parse every project to find the list of source files (that's easier than parsing the .sln, as vcxproj files are in xml). Look for
ClCompilexml nodes to extract the list of .cpp files. - Then you can identify which projects needs some files to be recompiled (getting list of modified files as script input parameter or based on timestamp checking)
Finally, to rebuild, you have two options:
- Call "msbuild " to recompile the whole project (vcxproj) (for instance
msbuild project.vcxproj /p:Configuration=Debug;TargetFrameworkVersion=v3.5) - You could also recompile a single file (
cl simple.cpp). To do so, you need to know what are theclbuild options to be sure you compile the file exactly the same way as Visual Studio would. If you earlier did a full build of the solution (it could be a rquirement for your script to work), then you should be able to find that from Visual Studio logs (within the target folder). In my solutions, I can find for every project (vcxproj file) a build log per configuration (in%OUTPUT_DIR%\lib\%libname%\%libname%.dir\%configuration%\%libname%.tlog\CL.command.1.tlog), this file reports the exactclarguments that were used to compile every file of the project. Then you can manually invokeclcommand and this should end up recompiling the file the same way Visual Studio would do it.
Additionnaly, you could add a project in your Visual Studio solution that would fire this script as a custom command.
Such a script should be able to identify which projects has to be rebuilt and rebuild them.
Answers 2
This is a very common requirement, it is never solved this way. What you are proposing is not completely impossible, but it is certainly very painful to implement. You are overlooking what should happen when you modify a .h file, that can force a bunch of .cpp files to be recompiled. And you are not considering linker errors. While you'll have a shot at discovering .cpp files, discovering #include file dependencies is very gritty. You can't get them from the project or make file. Compiling with /showIncludes and parsing the build trace files is what it takes. Nothing off-the-shelf afaik.
Don't do this, you'll regret it. Use the solution that everybody uses: you need a build server. Preferably with a continuous integration feature so the server kicks-off the build for all target platforms as soon as you check-in a code change. Many to choose from, this Q+A talks about it.
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