aaron.ballman added inline comments.
================
Comment at: clang/test/Lexer/Inputs/unsafe-macro-2.h:23-26
+// not-expected-warning@+1{{macro 'UNSAFE_MACRO_2' has been marked as unsafe
for use in headers}}
+#undef UNSAFE_MACRO_2
+// not-expected-warning@+1{{macro 'UNSAFE_MACRO_2' has been marked as unsafe
for use in headers}}
+#define UNSAFE_MACRO_2 2
----------------
beanz wrote:
> aaron.ballman wrote:
> > Why do we not expect warnings for these cases? I would have expected that
> > undefining a macro is just as unsafe for ABI reasons as defining a macro is.
> I kinda waffled on this myself. My thought was to treat this similarly to how
> we handle the macro redefinition warning. If you `undef`, you're kind of
> claiming the macro as your own and all bets are off...
>
> That said, my next clang extension closes that loop hole too:
> https://github.com/llvm-beanz/llvm-project/commit/f0a5216e18f5ee0883039095169bd380295b1de0
So `header_unsafe` is "diagnose if someone expands this macro from outside the
main source file" and `final` is "diagnose if someone defines or undefines this
macro anywhere", correct? Would it make sense to have a shorthand to combine
these effects for a "fully reserved" macro identifier (`#pragma clang
reserve_macro(IDENT[, msg])` as a strawman)?
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D107095/new/
https://reviews.llvm.org/D107095
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