How to improve Visual C++ compilation times?

Question

One thing that slows down the VC++ compiler is if you have a header file that initializes concrete instances of non-trival const value types. You may see this happen with constants of type std::string or GUIDs. It affects both compilation and link time.

For a single dll, this caused a 10x slowdown. It helps if you put them in a precompiled header file, or, just declare them in a header and initialize them in a cpp file.

Do take a look into the virus scanner, and be sure to experiment with precompiled headers, without it you won't see VC++ at its best.

Oh yeah, and make sure the %TMP% folder is on the same partition as where your build is written to, as VC++ makes temp files and moves them later.

The projects depending on each other doesn't imply that no parallelization is possible. The build systems are smart enough to figure out and avoid critical depenedancies, Otherwise gcc wouldn't be able to use 4 cores.

So (in addition to other steps), why not just try enabling multiprocessing in Visual Studio using /MP (See http://msdn.microsoft.com/en-us/library/bb385193.aspx).

It's not the direct answer for the question but at my company we are using IncrediBuild for distributed compilation. It really speeds up the compilation process. http://incredibuild.com/visual_studio.htm

How are you building the Visual Studio projects? Are you just running the ide (devenv) with the project and /build or do you have a makefile similar to what I assume you are using for gcc. I'm assuming that both builds use a similar makefile but I thought it worth checking.

Are you using precompiled headers for either compiler? If you're NOT using precompiled headers for VS then you might like to switch to using them. Personally I'd recommend using the #pragma hdrstop approach rather than a single all inclusive header file but if you're currently NOT using precompiled headers and want to try it out a single all inclusive header file that is force included (using the /FI compiler command line switch) can be tested quickly without any code changes.

I wrote about both /FI and #pragma hdrstop here: http://www.lenholgate.com/blog/2004/07/fi-stlport-precompiled-headers-warning-level-4-and-pragma-hdrstop.html

The book "Large-Scale C++ Software Design" by John Lakos has many tips on structuring your code and design for large-scale projects. Including many tips on speeding up compilation. Not directly related to Visual C++, but well worth reading anyway.