How to speed up build times with plugins?

Development Programming & Scripting C++
1

Might anyone know why I am getting maddeningly long build times due to plugins being rebuilt at every build, even though I’m only changing project-specific files?

All of the Build.cs files (both for the project and the plugins) have “PCHUsage = PCHUsageMode.UseExplicitOrSharedPCHs”.

I tried adding “bUsePrecompiled = true” to the plugins’ Build.cs files, but then it was the creation of the library [ProjectName]Editor-000X.dll (where X was some digit) that started taking a long time. I copied the plugin folders from the project’s Plugins folder to Engine\Plugins\Marketplace, but to no avail: the local plugins continue to get rebuilt.

I would be extremely grateful for any help, as this is getting infuriating.

2

If you turn on the build debug flags for MSBuild, what does it say about why it rebuilds things?

Maybe there’s something about modification times? Maybe you keep changing some header they’re all including?

3

Thank you for your reply. I generated a build log with the verbosity set to “diagnostic” but it is nearly 9,000 lines long and I’m afraid I don’t know what to look for.

I don’t think it has to do with accidentally changing a generally included header file as this recompilation happens even when I only make a minute change to a project cpp file and editing of any other code file is locked by Perforce.

Here are the plugins’ .Build.cs files — note that the ones for FMOD Studio have “PrivatePCHHeaderFile” settings, which I think might be part of the problem (FMOD Studio is by far the longest plugin to recompile):
https://pastebin.com/AN2eb8xD
https://pastebin.com/rQ2bdG6g
https://pastebin.com/e4j0q0qr
https://pastebin.com/xJdMSTwn

Thanks again for your reply and any help you might be able to provide.