[libcxx-commits] [PATCH] D68617: partially inline copy constructor basic_string(const basic_string&[, allocator])

Wed Oct 16 07:50:15 PDT 2019

ldionne requested changes to this revision.
ldionne added inline comments.
This revision now requires changes to proceed.

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Comment at: libcxx/include/__config:766
+#define _LIBCPP_HIDE_FROM_ABI_IN_UNSTABLE _LIBCPP_HIDE_FROM_ABI
+#define _LIBCPP_INLINE_IN_UNSTABLE inline
+#else
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I'm really uncomfortable with piggy-backing on the fact that non-inline member functions with an explicit instantiation declaration won't be inlined into user code. We're also excluding this optimization from most builds which are not using the unstable ABI.

I think it's possible to do better by encoding the knowledge of when `__init_long()` was added to the shared library. As far as you're concerned, you could basically write code using `_LIBCPP_HAS_INIT_LONG_IN_DYLIB` (or whatever), and then vendors could go and define that macro when suitable for them.

We could also define all these `_LIBCPP_HAS_<function-name>_IN_DYLIB` macros in case we're using the unstable ABI. WDYT?

Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D68617/new/

https://reviews.llvm.org/D68617