Re:LLVM 9.0
by The_rationalist on Thursday September 19, 2019 @04:00PM
(#21020102)
Interesting so this means that if someone really want llvm to support an extension (say a C attribute) that GCC supports, then you "just" have to make a contribution to the Linux kernel that use the gcc attribute and that is a minimum useful.
Then LLVM will prioritize the support of said attribute.
As such, hardcore developers might become new Linux contributors just as an Indirect (but effective) way to force LLVM/clang to add support for an attribute.
Yes, this is in fact a viable strategy. Source: I contributed a few GCC extension in Clang forced by Linux kernel.
Re:LLVM 9.0
by spacepinball on Thursday September 19, 2019 @08:54PM
(#21022291)
Rational indeed
Who in the world would do that rather than just supporting both compilers?
Re:LLVM 9.0
by The_rationalist on Thursday September 19, 2019 @05:07PM
(#21020781)
You don't seems to understand that extensions/attributes can have a usefulness that far outweight cross compiler compatibility?
Type of reasons: Performance critical; Security; Expressivity;
Each of them can be a necessary reason. E.g "polymorphism" in C through transparent unions
It was already possible to compile the kernel with clang/llvm. But a few releases ago, the Linux kernel dropped support for being built with older compilers which did not have support for the "asm goto" gcc extension.
The Linux kernel has always targeted gcc exclusively, and makes heavy use of gcc extensions since its very first release. The only reason clang can compile the Linux kernel is that the clang developers implemented support for the many gcc extensions the Linux kernel uses.