On 2023-11-07 11:33, Nicola Vetrini wrote:
This series is aimed at presenting some strategies that can be used to
deal with
violations of Rule 15.2:
"The goto statement shall jump to a label declared later in the same
function".
The rule's rationale is about possible developer confusion, therefore
it could
be argued that there is no substantial gain in complying with it, given
the
torough review process in place.
Nonetheless, the proposed resolution strategies are the following:
- use a loop instead of a goto (see patch 1 and 3)
- make the jump due to the goto forward, rather than backward (see
patch 2)
- unconditionally allow certain constructs, such as "goto retry", whose
presence
in the codebase typically signifies that all other reasonable
approaches (e.g,
loops, forward jumps) have been considered and deemed inferior in
terms of
code readability.
The latter strategy may be postponed until all goto-s with a certain
label have
been examined. An alternative strategy could be to allow certain files
(most notably those under x86/x86_emulate) to have backward jumps, and
resolve
the remaining violations.
Any feedback on this matter is welcome.
Nicola Vetrini (4):
xen/vsprintf: replace backwards jump with loop
x86/dom0: make goto jump forward
xen/arm: GICv3: address MISRA C:2012 Rule 15.2
automation/eclair: add deviation for certain backwards goto
.../eclair_analysis/ECLAIR/deviations.ecl | 10 +++
docs/misra/deviations.rst | 10 +++
xen/arch/arm/gic-v3-its.c | 81 ++++++++++---------
xen/arch/x86/dom0_build.c | 14 ++--
xen/common/vsprintf.c | 20 +++--
5 files changed, 81 insertions(+), 54 deletions(-)
Cc: all involved maintainers
In concert with Stefano, and given the feedback received on this RFC
series, it has been decided to deviate globally this rule, on the
grounds that there are already guidelines on the usage of goto-s within
Xen, so it was deemed not worth pursuing the resolution of these
violations. Therefore, the patches contained here can be ignored for the
purposes of MISRA compliance.
--
Nicola Vetrini, BSc
Software Engineer, BUGSENG srl (https://bugseng.com)