On Thu, May 21, 2020 at 7:22 AM 'Marco Elver' via Clang Built Linux <clang-built-li...@googlegroups.com> wrote: > > It appears that compilers have trouble with nested statement > expressions. Therefore remove one level of statement expression nesting > from the data_race() macro. This will help us avoid potential problems > in future as its usage increases. > > Link: https://lkml.kernel.org/r/20200520221712.ga21...@zn.tnic > Acked-by: Will Deacon <w...@kernel.org> > Signed-off-by: Marco Elver <el...@google.com>
Thanks Marco, I can confirm this series fixes the significant build time regressions. Tested-by: Nick Desaulniers <ndesaulni...@google.com> More measurements in: https://github.com/ClangBuiltLinux/linux/issues/1032 Might want: Reported-by: Borislav Petkov <b...@suse.de> Reported-by: Nathan Chancellor <natechancel...@gmail.com> too. > --- > v3: > * Fix for 'const' non-scalar expressions. > v2: > * Add patch to series in response to above linked discussion. > --- > include/linux/compiler.h | 10 +++++----- > 1 file changed, 5 insertions(+), 5 deletions(-) > > diff --git a/include/linux/compiler.h b/include/linux/compiler.h > index 7444f026eead..379a5077e9c6 100644 > --- a/include/linux/compiler.h > +++ b/include/linux/compiler.h > @@ -211,12 +211,12 @@ void ftrace_likely_update(struct ftrace_likely_data *f, > int val, > */ > #define data_race(expr) > \ > ({ \ > - __kcsan_disable_current(); \ > - ({ \ > - __unqual_scalar_typeof(({ expr; })) __v = ({ expr; }); \ > - __kcsan_enable_current(); \ > - __v; \ > + __unqual_scalar_typeof(({ expr; })) __v = ({ \ > + __kcsan_disable_current(); \ > + expr; \ > }); \ > + __kcsan_enable_current(); \ > + __v; \ > }) > > /* > -- > 2.26.2.761.g0e0b3e54be-goog > > -- > You received this message because you are subscribed to the Google Groups > "Clang Built Linux" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to clang-built-linux+unsubscr...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/clang-built-linux/20200521142047.169334-10-elver%40google.com. -- Thanks, ~Nick Desaulniers
