diff options
Diffstat (limited to 'absl/base/attributes.h')
| -rw-r--r-- | absl/base/attributes.h | 27 |
1 files changed, 10 insertions, 17 deletions
diff --git a/absl/base/attributes.h b/absl/base/attributes.h index d710f287..52139556 100644 --- a/absl/base/attributes.h +++ b/absl/base/attributes.h @@ -599,31 +599,24 @@ // case 42: // ... // -// Notes: when compiled with clang in C++11 mode, the ABSL_FALLTHROUGH_INTENDED -// macro is expanded to the [[clang::fallthrough]] attribute, which is analysed -// when performing switch labels fall-through diagnostic -// (`-Wimplicit-fallthrough`). See clang documentation on language extensions -// for details: +// Notes: When supported, GCC and Clang can issue a warning on switch labels +// with unannotated fallthrough using the warning `-Wimplicit-fallthrough`. See +// clang documentation on language extensions for details: // https://clang.llvm.org/docs/AttributeReference.html#fallthrough-clang-fallthrough // -// When used with unsupported compilers, the ABSL_FALLTHROUGH_INTENDED macro -// has no effect on diagnostics. In any case this macro has no effect on runtime +// When used with unsupported compilers, the ABSL_FALLTHROUGH_INTENDED macro has +// no effect on diagnostics. In any case this macro has no effect on runtime // behavior and performance of code. #ifdef ABSL_FALLTHROUGH_INTENDED #error "ABSL_FALLTHROUGH_INTENDED should not be defined." -#endif - -// TODO(zhangxy): Use c++17 standard [[fallthrough]] macro, when supported. -#if defined(__clang__) && defined(__has_warning) -#if __has_feature(cxx_attributes) && __has_warning("-Wimplicit-fallthrough") +#elif ABSL_HAVE_CPP_ATTRIBUTE(fallthrough) +#define ABSL_FALLTHROUGH_INTENDED [[fallthrough]] +#elif ABSL_HAVE_CPP_ATTRIBUTE(clang::fallthrough) #define ABSL_FALLTHROUGH_INTENDED [[clang::fallthrough]] -#endif -#elif ABSL_INTERNAL_HAVE_MIN_GNUC_VERSION(7, 0) +#elif ABSL_HAVE_CPP_ATTRIBUTE(gnu::fallthrough) #define ABSL_FALLTHROUGH_INTENDED [[gnu::fallthrough]] -#endif - -#ifndef ABSL_FALLTHROUGH_INTENDED +#else #define ABSL_FALLTHROUGH_INTENDED \ do { \ } while (0) |