Author: smeenai Date: Wed Oct 12 08:48:14 2016 New Revision: 284016 URL: http://llvm.org/viewvc/llvm-project?rev=284016&view=rev Log: [libc++] Correct explanation of _LIBCPP_NEW_DELETE_VIS
The behavior of this macro actually needs to apply universally on Windows and not just when using the Microsoft CRT. Update the macro definition and documentation accordingly. Differential Revision: https://reviews.llvm.org/D25145 Modified: libcxx/trunk/docs/DesignDocs/VisibilityMacros.rst libcxx/trunk/include/new Modified: libcxx/trunk/docs/DesignDocs/VisibilityMacros.rst URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/docs/DesignDocs/VisibilityMacros.rst?rev=284016&r1=284015&r2=284016&view=diff ============================================================================== --- libcxx/trunk/docs/DesignDocs/VisibilityMacros.rst (original) +++ libcxx/trunk/docs/DesignDocs/VisibilityMacros.rst Wed Oct 12 08:48:14 2016 @@ -112,14 +112,15 @@ Visibility Macros Mark a symbol as being exported by the libc++ library. This macro must be applied to all `operator new` and `operator delete` overloads. - **Windows Behavior**: When using the Microsoft CRT, all the `operator new` and - `operator delete` overloads are defined statically in `msvcrt.lib`. Marking - them as `dllimport` in the libc++ `<new>` header is therefore undesirable: if - we were to mark them as `dllimport` and then link against libc++, source files - which included `<new>` would end up linking against libc++'s `operator new` - and `operator delete`, while source files which did not include `<new>` would - end up linking against msvcrt's `operator new` and `operator delete`, which - would be a confusing and potentially error-prone inconsistency. + **Windows Behavior**: The `operator new` and `operator delete` overloads + should not be marked as `dllimport`; if they were, source files including the + `<new>` header (either directly or transitively) would lose the ability to use + local overloads of `operator new` and `operator delete`. On Windows, this + macro therefore expands to `__declspec(dllexport)` when building the library + and has an empty definition otherwise. A related caveat is that libc++ must be + included on the link line before `msvcrt.lib`, otherwise Microsoft's + definitions of `operator new` and `operator delete` inside `msvcrt.lib` will + end up being used instead of libc++'s. Links ===== Modified: libcxx/trunk/include/new URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/include/new?rev=284016&r1=284015&r2=284016&view=diff ============================================================================== --- libcxx/trunk/include/new (original) +++ libcxx/trunk/include/new Wed Oct 12 08:48:14 2016 @@ -125,7 +125,7 @@ _LIBCPP_FUNC_VIS new_handler get_new_han } // std -#if defined(_LIBCPP_MSVCRT) && !defined(_LIBCPP_BUILDING_LIBRARY) +#if defined(_WIN32) && !defined(_LIBCPP_BUILDING_LIBRARY) # define _LIBCPP_NEW_DELETE_VIS #else # define _LIBCPP_NEW_DELETE_VIS _LIBCPP_FUNC_VIS _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits