aaron.ballman added a comment.
In D131464#3716905 <https://reviews.llvm.org/D131464#3716905>, @MaskRay wrote:
> Sorry, my previous main comment had been written before I introduced
> `LIT_CLANG_STD_GROUP` in `llvm/utils/lit/lit/llvm/config.py`. The multiple
> `%clang_cc1` approach actually looks like the following.
> Note the use of `%stdcxx_17-` to make the test future-proof.
> (It is non-trivial to run one `RUN` line multiples times with different
> `LIT_CLANG_STD_GROUP`. For now I just test locally with different
> `LIT_CLANG_STD_GROUP`.)
>
> // RUN: %clang_cc1 %s -fsyntax-only -verify=expected,precxx17 %stdcxx_11-14
> -fdata-sections -fcolor-diagnostics
> // RUN: %clang_cc1 %s -fsyntax-only -verify %stdcxx_17- -fdata-sections
> -fcolor-diagnostics
>
> ...
> TypedefAligned4 TA8c = TA8a + TA8b; // expected-warning {{passing 4-byte
> aligned argument to 8-byte aligned parameter 'this' of 'operator+' may result
> in an unaligned pointer access}} \
> // expected-warning {{passing 4-byte
> aligned argument to 8-byte aligned parameter 1 of 'operator+' may result in
> an unaligned pointer access}} \
> // precxx17-warning {{passing 4-byte
> aligned argument to 8-byte aligned parameter 'this' of 'StructAligned8' may
> result in an unaligned pointer access}}
Personally, I like this style. I tend to be a heavy user of `-verify` prefixes
though, so I might be biased.
> If this is changed to use `#if __cplusplus >= 201703L`, there will be
> multiple lines with relative line numbers (e.g. `@-2` `@-4`)
>
> register int ro; // expected-error {{illegal storage class on file-scoped
> variable}}
> #if __cplusplus >= 201703L
> // expected-error@-2 {{ISO C++17 does not allow 'register' storage class
> specifier}}
> #elif __cplusplus >= 201103L
> // expected-warning@-4 {{'register' storage class specifier is deprecated}}
> #endif
FWIW, you don't have to use relative markers, but that uses an even less common
idiom of bookmarks. e.g.,
register int ro; // expected-error {{illegal storage class on file-scoped
variable}} \
#bookmark
#if __cplusplus >= 201703L
// expected-error@#bookmark {{ISO C++17 does not allow 'register' storage
class specifier}}
#elif __cplusplus >= 201103L
// expected-warning@#bookmark {{'register' storage class specifier is
deprecated}}
#endif
> Personally I prefer multiple `%clang_cc1` over `#if`. The first few lines
> give users a first impression. The dispatch makes it clear the test has
> different behaviors with the `%stdcxx_*` described dialects.
I tend to have the same opinion.
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D131464/new/
https://reviews.llvm.org/D131464
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