about those clang warnings

[René J.V. Bertin]

On Wednesday January 27 2016 16:15:05 Kevin Funk wrote:

> Non-static build of the Clang/LLVM executables is another issue. Runtime 
> relocations have an immense impact on execution time of those tools (esp. 
> since they're usually short-living processes, invoked numerous times)

Ah, you mean whether or not clang or clang++ link to libLLVM? That is indeed the case for the MacPorts llvm/clang builds, and not for Apple's system clang from what I can see.

Your explanation should mean that any performance differences (due to runtime relocation) should disappear when compiling large enough files, which isn't exactly what I'm seeing (705Kb small C file):

/usr/bin/clang (600.0.57 based on LLVM 3.5): 5.308 user_cpu 0.153 kernel_cpu 0:05.70 total_time 95.6%CPU
    (hah, so it isn't a 3.6 version after all...)
/opt/local/bin/clang-mp-3.6 (3.6.2/final): 7.999 user_cpu 0.170 kernel_cpu 0:08.17 total_time 99.8%CPU
/opt/local/bin/clang-mp-3.7 (3.7.0/final): 9.229 user_cpu 0.167 kernel_cpu 0:09.63 total_time 97.4%CPU

Cheers,
René