On Fri, Apr 09, 2021 at 12:55:18PM +0200, Florian Weimer wrote:
> * Ard Biesheuvel:
>
> > Wouldn't that require the compiler to interpret the contents of the
> > asm() block?
>
> Yes and no. It would require proper toolchain support, so in this case
> a new ELF relocation type, with compiler, assembler, and linker support
> to generate those relocations and process them. As far as I understand
> it, the kernel doesn't do things this way.
I don't think that all is needed. All we need is for the compiler to
recognise that:
if (cond) {
stmt-A;
}
if (cond) {
stmt-B;
}
both cond are equivalent and hence can merge the blocks like:
if (cond) {
stmt-A;
stmt-B;
}
But because @cond is some super opaque asm crap, the compiler throws up
it's imaginry hands and says it cannot possibly tell and leaves them as
is.
