On Thu, Oct 28, 2021 at 11:07:40PM +0900, Masahiro Yamada wrote:

On Thu, Oct 28, 2021 at 10:44 PM Peter Zijlstra [off-list ref] wrote:

quoted

Hi,

Debian (and derived) distros ship their compilers as -$ver suffixed
binaries. For gcc it is sufficent to use:

 $ make CC=gcc-12

However, clang builds (esp. clang-lto) need a whole array of tools to be
exactly right, leading to unweildy stuff like:

 $ make CC=clang-13 LD=ld.lld=14 AR=llvm-ar-13 NM=llvm-nm-13 OBJCOPY=llvm-objcopy-13 OBJDUMP=llvm-objdump-13 READELF=llvm-readelf-13 STRIP=llvm-strip-13 LLVM=1

which is, quite franktly, totally insane and unusable. Instead use the
already mandatory LLVM variable to convey this, enabling one such as
myself to use:

 $ make LLVM=-13

This also lets one quickly test different clang versions.

Please read the commit log of
a0d1c951ef08ed24f35129267e3595d86f57f5d3

That's yuck, I like LLVM=-13 or LLVM=-12 much better to select between
compilers. Means I don't have to remember wth they live and or wreck
PATH.