aaron.ballman added a comment.
Is the attribute considered to be a property of the parameter or a property of
the function the parameter is declared in? e.g.,
void someOtherFunc(void (^cb)(void)) {
if (something())
cb();
}
void barWithCallback(void (^callback)(void) __attribute__((called_once))) {
someOtherFunc(callback);
}
Should code like that also diagnose given that `callback` is not called on
every code path? From the test cases you have, it looks like you explicitly
allow this code without diagnosing it, which suggests the attribute is really a
property of the function and not a property of the parameter. This in turn
makes me wonder whether a better design is for `-Wcompletion-handler` to
diagnose any function with a completion handler-like parameter if the parameter
is not called exactly once within the function, and the user marks the
functions that should be exempt from the checking rather than marking the
parameters that should be checked (or does this have too many false positives
in practice)? Alternatively, should the check be implemented as a clang static
analyzer check that tracks an annotated parameter across the inter-procedural
CFG and diagnoses such code?
================
Comment at: clang/include/clang/Basic/AttrDocs.td:5133-5134
+
+This attribute is useful for API developers who want to double-check if they
+implemented their method correctly.
+
----------------
Oh, I was thinking this attribute was enabling some optimization opportunities
or doing something more than just acting as a marker to please check this
function's correctness for some properties. This means that the programmer has
to annotate their code and enable the warning flag in order for either the
attribute or the warning flag to have effect, which feels a bit surprising to
me.
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D92039/new/
https://reviews.llvm.org/D92039
_______________________________________________
cfe-commits mailing list
cfe-commits@lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
