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| author |  Evan Brown <ezb@google.com> | 2022-07-27 13:45:19 -0700 |
|---|---|---|
| committer |  Copybara-Service <copybara-worker@google.com> | 2022-07-27 13:46:14 -0700 |
| commit | c7e60ccfcd708a73008ed2df040162c66697bc18 (patch) | |
| tree | 904eb83861d0174d48ee11b5637c8919be623d40 /absl/base/optimization.h | |
| parent | 51f6d868c8463ac13492d504cbc034e91b43a461 (diff) | |
Add ABSL_IS_TRIVIALLY_RELOCATABLE and ABSL_ATTRIBUTE_TRIVIAL_ABI macros for use with clang's __is_trivially_relocatable and [[clang::trivial_abi]].
PiperOrigin-RevId: 463668740
Change-Id: I2d2d2f53d8184a7e4f7c848c2a5f5140c2481d72
Diffstat (limited to 'absl/base/optimization.h')
| -rw-r--r-- | absl/base/optimization.h | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/absl/base/optimization.h b/absl/base/optimization.h index db5cc097..57999a18 100644 --- a/absl/base/optimization.h +++ b/absl/base/optimization.h @@ -249,4 +249,28 @@ #define ABSL_INTERNAL_UNIQUE_SMALL_NAME() #endif +// ABSL_IS_TRIVIALLY_RELOCATABLE(type) +// Detects whether a type is "trivially relocatable" -- meaning it can be +// relocated without invoking the constructor/destructor, using a form of move +// elision. +// +// Example: +// +// if constexpr (ABSL_IS_TRIVIALLY_RELOCATABLE(T)) { +// memcpy(new_location, old_location, sizeof(T)); +// } else { +// new(new_location) T(std::move(*old_location)); +// old_location->~T(); +// } +// +// Upstream documentation: +// +// https://clang.llvm.org/docs/LanguageExtensions.html#:~:text=__is_trivially_relocatable +// +#if ABSL_HAVE_BUILTIN(__is_trivially_relocatable) +#define ABSL_IS_TRIVIALLY_RELOCATABLE(type) __is_trivially_relocatable(type) +#else +#define ABSL_IS_TRIVIALLY_RELOCATABLE(type) false +#endif + #endif // ABSL_BASE_OPTIMIZATION_H_ |