[PATCH] D31272: Do not pass an explicit reexported symbol list when building libc++ dylib if also defining new/delete

[Eric Fiselier via Phabricator via cfe-commits]

EricWF added a comment.

In https://reviews.llvm.org/D31272#711860, @mehdi_amini wrote:

> In https://reviews.llvm.org/D31272#711804, @EricWF wrote:
>
> > I'm a bit confused by the description of this change. Libc++ has been enabling the new/delete definitions in its dylib since forever and I've never experienced a link error. Did you mean to say the link error occurs only when libc++abi doesn't define them?
>
>
> Most people have the "command line tools" package installed on macOS, and it means that you're taking this condition:
>
> `if (DEFINED CMAKE_OSX_SYSROOT AND NOT CMAKE_OSX_SYSROOT STREQUAL "")`
>
> which leads you to:
>
> `-Wl,-reexport_library,${CMAKE_OSX_SYSROOT}/usr/lib/libc++abi.dylib`
>
> While the GreenDragon bots don't have the command line tools, so CMAKE_OSX_SYSROOT is defined by cmake and then this is used instead:
>
> `set(OSX_RE_EXPORT_LINE "/usr/lib/libc++abi.dylib -Wl,-reexported_symbols_list,${CMAKE_CURRENT_SOURCE_DIR}/libc++abi${LIBCXX_LIBCPPABI_VERSION}.exp")`


I think you have that reversed. I have command line tools installed and `CMAKE_OSX_SYSROOT` isn't defined. Therefore the `else()` branch is taken and libc++abi is exported via the ABI list.


https://reviews.llvm.org/D31272