On 24.11.2025 03:18, Saman Dehghan wrote: > Clang >= 18 supports Modified Condition/Decision Coverage (MC/DC). > This patch enables the detection and usage of this feature when > compiling Xen with Clang. > > - Update detection logic to check for '-fcoverage-mcdc' when using Clang.
You check for ... > - Update llvm.c to handle the profile format changes (bitmap section) > required for MC/DC. > - Guard -Wno-error=coverage-too-many-conditions with CONFIG_CC_IS_GCC > to avoid passing a GCC-only warning option to Clang > > Signed-off-by: Saman Dehghan <[email protected]> > --- > xen/Kconfig | 2 +- > xen/Rules.mk | 1 + > xen/arch/x86/Makefile | 4 +++- > xen/common/coverage/llvm.c | 24 +++++++++++++++++++++++- > 4 files changed, 28 insertions(+), 3 deletions(-) > > diff --git a/xen/Kconfig b/xen/Kconfig > index a5e5af3b76..5508993f02 100644 > --- a/xen/Kconfig > +++ b/xen/Kconfig > @@ -53,7 +53,7 @@ config CC_HAS_ASM_GOTO_OUTPUT > > # Compiler supports -fcondition-coverage aka MC/DC > config CC_HAS_MCDC > - def_bool $(cc-option,-fcondition-coverage) > + def_bool $(cc-option,-fcondition-coverage) || > $(cc-option,-fprofile-instr-generate -fcoverage-mapping -fcoverage-mcdc) ... more than that one option here. Presumably because the option alone wouldn't be liked by the compiler? (May want mentioning in that part of the description.) > --- a/xen/arch/x86/Makefile > +++ b/xen/arch/x86/Makefile > @@ -99,7 +99,9 @@ ifneq ($(CONFIG_HVM),y) > $(obj)/x86_emulate.o: CFLAGS-y += -Wno-unused-label > endif > ifeq ($(CONFIG_CONDITION_COVERAGE),y) > -$(obj)/x86_emulate.o: CFLAGS-y += -Wno-error=coverage-too-many-conditions > + ifeq ($(CONFIG_CC_IS_GCC),y) > + $(obj)/x86_emulate.o: CFLAGS-y += > -Wno-error=coverage-too-many-conditions > + endif > endif Please can the two conditionals be combined, like I think we do elsewhere: ifeq ($(CONFIG_CONDITION_COVERAGE)$(CONFIG_CC_IS_GCC),yy) or ifeq ($(CONFIG_CONDITION_COVERAGE)_$(CONFIG_CC_IS_GCC),y_y) ? Jan
