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| -rw-r--r-- | clang/docs/ReleaseNotes.rst | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst index 9edbfbf..93a67e7 100644 --- a/clang/docs/ReleaseNotes.rst +++ b/clang/docs/ReleaseNotes.rst @@ -171,6 +171,22 @@ AST Dumping Potentially Breaking Changes "qualType": "foo" } +Clang Frontend Potentially Breaking Changes +------------------------------------------- +- Target OS macros extension + A new Clang extension (see :ref:`here <target_os_detail>`) is enabled for + Darwin (Apple platform) targets. Clang now defines ``TARGET_OS_*`` macros for + these targets, which could break existing code bases with improper checks for + the ``TARGET_OS_`` macros. For example, existing checks might fail to include + the ``TargetConditionals.h`` header from Apple SDKs and therefore leaving the + macros undefined and guarded code unexercised. + + Affected code should be checked to see if it's still intended for the specific + target and fixed accordingly. + + The extension can be turned off by the option ``-fno-define-target-os-macros`` + as a workaround. + What's New in Clang |release|? ============================== Some of the major new features and improvements to Clang are listed @@ -351,6 +367,15 @@ New Compiler Flags * Full register names can be used when printing assembly via ``-mregnames``. This option now matches the one used by GCC. +.. _target_os_detail: + +* ``-fdefine-target-os-macros`` and its complement + ``-fno-define-target-os-macros``. Enables or disables the Clang extension to + provide built-in definitions of a list of ``TARGET_OS_*`` macros based on the + target triple. + + The extension is enabled by default for Darwin (Apple platform) targets. + Deprecated Compiler Flags ------------------------- |