MISRA C Rule 20.7 states: "Expressions resulting from the expansion of macro parameters shall be enclosed in parentheses". Therefore, some macro definitions should gain additional parentheses to ensure that all current and future users will be safe with respect to expansions that can possibly alter the semantics of the passed-in macro parameter.
No functional change. Signed-off-by: Nicola Vetrini <[email protected]> --- Somewhat surprisingly, the change in the tools directory is also needed, otherwise some CI build jobs fail (see e.g. [1]). This is not undefined behaviour as long as the two definitions are kept in sync, following section 6.10.3p2 of the C99 standard, but having the definition in common-macros.h is still a potential problem. [1] https://gitlab.com/xen-project/people/bugseng/xen/-/jobs/6742878558 --- tools/include/xen-tools/common-macros.h | 2 +- xen/include/xen/unaligned.h | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/tools/include/xen-tools/common-macros.h b/tools/include/xen-tools/common-macros.h index 07aed92684b5..60912225cb7a 100644 --- a/tools/include/xen-tools/common-macros.h +++ b/tools/include/xen-tools/common-macros.h @@ -102,7 +102,7 @@ #define put_unaligned_t(type, val, ptr) do { \ struct { type x; } __packed *ptr_ = (typeof(ptr_))(ptr); \ - ptr_->x = val; \ + ptr_->x = (val); \ } while (0) #define get_unaligned(ptr) get_unaligned_t(typeof(*(ptr)), ptr) diff --git a/xen/include/xen/unaligned.h b/xen/include/xen/unaligned.h index 3eda0ece1199..2e8238d45c54 100644 --- a/xen/include/xen/unaligned.h +++ b/xen/include/xen/unaligned.h @@ -19,7 +19,7 @@ #define put_unaligned_t(type, val, ptr) do { \ struct { type x; } __packed *ptr_ = (typeof(ptr_))(ptr); \ - ptr_->x = val; \ + ptr_->x = (val); \ } while (0) #define get_unaligned(ptr) get_unaligned_t(typeof(*(ptr)), ptr) -- 2.34.1
