diff options
| author |  Derek Mauro <dmauro@google.com> | 2023-03-23 10:12:38 -0700 |
|---|---|---|
| committer |  Copybara-Service <copybara-worker@google.com> | 2023-03-23 10:13:24 -0700 |
| commit | b6de7b80325514018d38de2c4dee1254258c4b31 (patch) | |
| tree | 7bf4b7050a7665a151608a969c3c80fda8d3e686 /absl/base | |
| parent | 0a1e03a5f664fc8e2ab88cf2035b34fef651105a (diff) | |
Make `ABSL_ATTRIBUTE_NO_UNIQUE_ADDRESS` work on MSVC
https://devblogs.microsoft.com/cppblog/msvc-cpp20-and-the-std-cpp20-switch/#c20-no_unique_address
MSVC disables [[no_unique_address]] by default because of ABI
compatibility. Since Abseil does not claim ABI compatibility in
mixed-mode builds, we can offer it unconditionally.
Fixes #1418
PiperOrigin-RevId: 518894036
Change-Id: If7653e65703b335783f11d296de7e32fc35d4fc6
Diffstat (limited to 'absl/base')
| -rw-r--r-- | absl/base/attributes.h | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/absl/base/attributes.h b/absl/base/attributes.h index 91bf954b..a6572d08 100644 --- a/absl/base/attributes.h +++ b/absl/base/attributes.h @@ -787,7 +787,15 @@ // For code that is assured to only build with C++20 or later, prefer using // the standard attribute `[[no_unique_address]]` directly instead of this // macro. -#if ABSL_HAVE_CPP_ATTRIBUTE(no_unique_address) +// +// https://devblogs.microsoft.com/cppblog/msvc-cpp20-and-the-std-cpp20-switch/#c20-no_unique_address +// Current versions of MSVC have disabled `[[no_unique_address]]` since it +// breaks ABI compatibility, but offers `[[msvc::no_unique_address]]` for +// situations when it can be assured that it is desired. Since Abseil does not +// claim ABI compatibility in mixed builds, we can offer it unconditionally. +#if defined(_MSC_VER) && _MSC_VER >= 1929 +#define ABSL_ATTRIBUTE_NO_UNIQUE_ADDRESS [[msvc::no_unique_address]] +#elif ABSL_HAVE_CPP_ATTRIBUTE(no_unique_address) #define ABSL_ATTRIBUTE_NO_UNIQUE_ADDRESS [[no_unique_address]] #else #define ABSL_ATTRIBUTE_NO_UNIQUE_ADDRESS |