[llvm] r241663 - Revert r241621, "[CMake] Cleanup tools/CMakeLists.txt to take advantage of the auto-registration that was already partially working."

[Chris Bieneman]

> On Jul 8, 2015, at 3:06 PM, NAKAMURA Takumi <geek4civic at gmail.com> wrote:
> 
> Chris,
> 
> 2015-07-09 2:21 GMT+09:00 Chris Bieneman <beanz at apple.com>:
>> I was unaware anyone was using that setting through the CMake command line, and there was a corresponding bug in my change that I can address. The other issue is that my patches renamed all the LLVM_EXTERNAL_*_* settings to LLVM_TOOL_*_* because they apply to both in and out of tree tools.
>> 
>> Is there a reason you use this mechanism? For me to re-land my changes you’ll need to update your bots to use the new setting, or to not rely on this mechanism.
> 
> I am sorry that I didn't notice you supposed LLVM_EXTERNAL_*(s) were
> trivial and I didn't explain since I supposed they were precious.
> I am investigating bugs around there, later.
> 
>> Additionally, your bot doesn’t log its CMake invocation anywhere in the logs that I can see. Can you please update the bot so that it has its CMake invocation logged somewhere on every build so that issues like this can be triaged more easily? Without knowing that you were using the LLVM_EXTERNAL_CLANG_* flags there was no way for me to tell what was going wrong or to reproduce the issue.
> 
> Most of my builders are incremental and usually they don't put
> configurations to the log. I know such a behavior is inconvenient.

I see no problem with the builders being incremental. Can you just log the configuration in the build output? Maybe echo the command line out to the terminal so that people triaging failures know how the build was configured.

> 
> It is doing reconfiguration in every build but it is prioritized
> lower. http://bb.pgr.jp/builders/clang-3stage-x86_64-linux
> Others are built from clean in every Morning. FYI for example,
>  http://bb.pgr.jp/builders/cmake-clang-x86_64-linux/builds/37092
>  http://bb.pgr.jp/builders/ninja-clang-i686-msc18-R/builds/2192
> 
> FYI, Michael's r155654 was the last change for configuration.
> I am not a fan of names, LLVM_TOOL_*. I think they are still external.

With my changes this doesn’t just apply to external tools. In fact I want to completely get rid of the distinction of external tool subdirectories in CMake because I don’t think it adds any value.

Do you have an alternate suggestion for naming that isn’t EXTERNAL? This naming will apply to tools like llc and opt as well as clang and lld. I’m not married to the LLVM_TOOL_* naming, I just felt that LLVM_EXTERNAL_LLC_* would be a terribly misleading setting name.

Thanks,
-Chris

> 
> I won't stop cleanups. CMake scripts are messy.
> 
> ...Takumi