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| author | Eric Fiselier <eric@efcs.ca> | 2015-10-14 00:22:05 +0000 |
|---|---|---|
| committer | Eric Fiselier <eric@efcs.ca> | 2015-10-14 00:22:05 +0000 |
| commit | 29ada6d178890d843133fd67300b96427951086a (patch) | |
| tree | 622a034b460d3d84e596ec995acf1e2e5d61d378 /libcxx/docs/DesignDocs | |
| parent | ebd3f44f9349d3a8df956ed3e4d8229ac9c9248f (diff) | |
| download | bcm5719-llvm-29ada6d178890d843133fd67300b96427951086a.tar.gz bcm5719-llvm-29ada6d178890d843133fd67300b96427951086a.zip | |
Use __config_site when building libc++. Also cleanup ABI versioning doc
llvm-svn: 250261
Diffstat (limited to 'libcxx/docs/DesignDocs')
| -rw-r--r-- | libcxx/docs/DesignDocs/ABIVersioning.rst | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/libcxx/docs/DesignDocs/ABIVersioning.rst b/libcxx/docs/DesignDocs/ABIVersioning.rst new file mode 100644 index 00000000000..5960dd18610 --- /dev/null +++ b/libcxx/docs/DesignDocs/ABIVersioning.rst @@ -0,0 +1,17 @@ + +==================== +Libc++ ABI stability +==================== + +Libc++ aims to preserve stable ABI to avoid subtle bugs when code built to the old ABI +is linked with the code build to the new ABI. At the same time, libc++ allows ABI-breaking +improvements and bugfixes for the scenarios when ABI change is not a issue. + +To support both cases, libc++ allows specifying the ABI version at the +build time. The version is defined with a cmake option +LIBCXX_ABI_VERSION. Another option LIBCXX_ABI_UNSTABLE can be used to +include all present ABI breaking features. These options translate +into C++ macro definitions _LIBCPP_ABI_VERSION, _LIBCPP_ABI_UNSTABLE. + +Any ABI-changing feature is placed under it's own macro, _LIBCPP_ABI_XXX, which is enabled +based on the value of _LIBCPP_ABI_VERSION. _LIBCPP_ABI_UNSTABLE, if set, enables all features at once. |
