MISRA C Rule 20.7 states: "Expressions resulting from the expansion
of macro parameters shall be enclosed in parentheses".
The helper macro bitmap_switch has parameters that cannot be parenthesized
in order to comply with the rule, as that would break its functionality.
Moreover, the risk of misuse due developer confusion is deemed not
substantial enough to warrant a more involved refactor, thus the macro
is deviated for this rule.
No functional change.
Signed-off-by: Nicola Vetrini <nicola.vetr...@bugseng.com>
---
Changes in v2:
- Switched to a comment-based deviation to allow other tools to
pick this deviation up automatically.
---
docs/misra/safe.json | 8 ++++++++
xen/include/xen/bitmap.h | 3 +++
2 files changed, 11 insertions(+)
diff --git a/docs/misra/safe.json b/docs/misra/safe.json
index c213e0a0be3b..3f18ef401c7d 100644
--- a/docs/misra/safe.json
+++ b/docs/misra/safe.json
@@ -60,6 +60,14 @@
},
{
"id": "SAF-7-safe",
+ "analyser": {
+ "eclair": "MC3R1.R20.7"
+ },
+ "name": "MC3R1.R20.7: deliberately non-parenthesized macro
argument",
+ "text": "A macro parameter expands to an expression that is
non-parenthesized, as doing so would break the functionality."
+ },
+ {
+ "id": "SAF-8-safe",
"analyser": {},
"name": "Sentinel",
"text": "Next ID to be used"
diff --git a/xen/include/xen/bitmap.h b/xen/include/xen/bitmap.h
index b9f980e91930..6ee39aa35ac6 100644
--- a/xen/include/xen/bitmap.h
+++ b/xen/include/xen/bitmap.h
@@ -103,10 +103,13 @@ extern int bitmap_allocate_region(unsigned long *bitmap,
int pos, int order);
#define bitmap_switch(nbits, zero, small, large) \
unsigned int n__ = (nbits); \
if (__builtin_constant_p(nbits) && !n__) { \
+ /* SAF-7-safe Rule 20.7 non-parenthesized macro argument */ \
zero; \
} else if (__builtin_constant_p(nbits) && n__ <= BITS_PER_LONG) { \
+ /* SAF-7-safe Rule 20.7 non-parenthesized macro argument */ \
small; \
} else { \
+ /* SAF-7-safe Rule 20.7 non-parenthesized macro argument */ \
large; \
}
--
2.34.1
