[v1,0/3] Enable MC/DC support for GCOV

Message

Volodymyr Babchuk March 27, 2025, 12:40 a.m. UTC

This series enables MC/DC for Xen when building with GCC.

Condition coverage, also known as MC/DC (modified condition/decision
coverage) is a coverage metric that tracks separate outcomes in
boolean expressions. This metric is used in critical software
components, so it natural to collect it for Xen.

Second patch in the series ("xen: x86: irq: initialize irq desc in
create_irq()") deals with unexpected GCC issue. I haven't found a
better way to fix it.

This series support only GCC, although Clang, starting with clang 18.
supports similar feature. But Clang 18 uses raw profiling format
version 10, while Xen supports only version 4, and there are quite
substantial changes in headers and structures, so adding new version
format is non-trivial. Also, Xen built for aarch64 with clang 19.1.17
and code coverage enabled, completely hangs up during boot, so there
is clearly more work required. But at least we can have MC/DC with GCOV.

Volodymyr Babchuk (3):
  xen: gcov: add support for gcc 14.1
  xen: x86: irq: initialize irq desc in create_irq()
  xen: debug: gcov: add condition coverage support

 xen/Kconfig.debug               | 9 +++++++++
 xen/Rules.mk                    | 3 +++
 xen/arch/x86/irq.c              | 2 +-
 xen/common/coverage/gcc_4_7.c   | 8 +++++++-
 xen/common/coverage/gcov_base.c | 5 +++++
 5 files changed, 25 insertions(+), 2 deletions(-)