[PATCH] D30240: enable building with LTO on Windows using clang-cl and lld

[Reid Kleckner via Phabricator via llvm-commits]

rnk added inline comments.


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Comment at: llvm/trunk/cmake/modules/HandleLLVMOptions.cmake:717
+    append("-flto=thin" CMAKE_EXE_LINKER_FLAGS CMAKE_SHARED_LINKER_FLAGS)
+  endif()
   # On darwin, enable the lto cache. This improves initial build time a little
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mehdi_amini wrote:
> mehdi_amini wrote:
> > I don't understand this, this sounds suspicious to me. This is the flag we use to invoke *clang* for the linker step AFAIK, and it is up to clang to not pass the flag down to the lld-link job if not supported. 
> For instance ld64 on macOS does not accept -flto either, but we still configure -flto here for the link stage invocation and leave up to the clang driver to handle the correct linker invocation.
On Windows, nobody invokes the compiler to do the link step, except people porting build systems from Unix.


Repository:
  rL LLVM

https://reviews.llvm.org/D30240