On Thu, Jun 04, 2026 at 10:45:19AM +0200, Peter Zijlstra wrote: > On Wed, Jun 03, 2026 at 07:43:29PM +0200, Yunseong Kim wrote: > > Add CFLAGS_KCOV_DATAFLOW and RUSTFLAGS_KCOV_DATAFLOW exports to > > scripts/Makefile.kcov, containing: > > -fsanitize-coverage=dataflow-args,dataflow-ret -g > > (with optional -fno-inline via CONFIG_KCOV_DATAFLOW_NO_INLINE) > > > > scripts/Makefile.lib applies these flags when a module's Makefile sets: > > KCOV_DATAFLOW_file.o := y (per-file) > > KCOV_DATAFLOW := y (per-directory) > > > > Also supports CONFIG_KCOV_DATAFLOW_INSTRUMENT_ALL for global enablement. > > The flags are only applied to kernel objects (same guard as basic KCOV). > > > > Signed-off-by: Yunseong Kim <[email protected]> > > --- > > scripts/Makefile.kcov | 6 ++++++ > > scripts/Makefile.lib | 7 +++++++ > > 2 files changed, 13 insertions(+) > > > > diff --git a/scripts/Makefile.kcov b/scripts/Makefile.kcov > > index 78305a84ba9d..101173fe194b 100644 > > --- a/scripts/Makefile.kcov > > +++ b/scripts/Makefile.kcov > > @@ -2,10 +2,16 @@ > > kcov-flags-y += > > -fsanitize-coverage=trace-pc > > kcov-flags-$(CONFIG_KCOV_ENABLE_COMPARISONS) += > > -fsanitize-coverage=trace-cmp > > > > +# KCOV dataflow: trace function args and return values > > +kcov-dataflow-flags-y := -fsanitize-coverage=dataflow-args,dataflow-ret -g > > +kcov-dataflow-flags-$(CONFIG_KCOV_DATAFLOW_NO_INLINE) += -fno-inline > > https://clang.llvm.org/docs/ClangCommandLineReference.html > > Has no mention of -fno-inline, furthermore, what are the exact > semantics? Does it inhibit __always_inline? >
Based on clang/test/CodeGen/always-inline.c [1], I believe the semantics are the same as GCC's '-fno-inline' [2], which avoids inlining except for always_inline functions. [1]: https://github.com/llvm/llvm-project/blob/1d13b74cf086629d5cdae5f44ef4a62cebcaf3ff/clang/test/CodeGen/always-inline.c [2]: https://gcc.gnu.org/onlinedocs/gcc/Optimize-Options.html#index-fno-inline -- Cheers, Nathan
