[cfe-dev] Slowness of clang build

[Edward Diener]

I am periodically retrieving the latest sources from the llvm/clang 
repository, as specified in the Getting Started page.

When I do a build of clang, through the 'make' command from the build 
directory, the build runs very slow. Evidently the default is a 
Debug+Assert build. Compiling a single source file averages 5-10 seconds 
and overall the build takes hours considering how many modules must be 
built. It is all successful in the end and when I am finished I have the 
latest clang, which is great.

I have plenty of memory, plenty of disk space, a fairly fast CPU, and am 
doing the build on Fedora 17 with hardly any other applications running.

Why is compiling clang so slow ? Is there any way to speed up the build 
? If I do a release build ( how ? )is it significantly quicker ?