Building Clang from the distribution files - Git errors and VCSRevision.h

Clang Frontend
1

Hi

I am building LLVM and Clang from the distribution files using CMake, Ninja and gcc 7.1. I can usually get a clean run on this.

I have noticed with Clang 9.0.0 that I get some error messages which seem to be related to a file VCSRevision.h and a search for git. It declares this to be fatal and carries on!

There is very little in the documentation about how to build LLVM and Clang from a distribution as compared to cloning from Git. I am wondering if the build is assuming that git init has been run in the build location.

I have read in the documentation about the CMake variable LLVM_APPEND_VC_REV which is defaulted to ON. Should I be changing this value to OFF?

It would be helpful to have an official manual for building from a distribution along the lines of this unofficial one which I have found to be helpful although now dated: http://chiselapp.com/user/ttmrichter/repository/gng/doc/trunk/output/blog/2016/01-llvm-clang-missing-manual.html

Best wishes

John Fletcher

2

Have you already looked at this page?

What OS are you on?

Neil Nelson

3

Neil

Thank you. I have seen the Getting Started page and it assumes working from a Git clone and not from the distribution files, so it is not dealing with my question.

I am running on Ubuntu Linux 14.04 which I know is old. I have more recent gcc including 7.1 which I am currently using for building Clang which I have done for successive versions for some years.

The build of 9.0.0 does work. I would like to resolve the issue of messages about Git and VCSRevision.h.

John

P.S. My apologies. The email system imposed on me recently does not seem to have an option to quote a message when replying.