[PATCH] D55627: [ThinLTO] Change locally defined symbols marked dllimport to dllexport

[Reid Kleckner via Phabricator via llvm-commits]

rnk added a comment.

Why add dllexport instead of just removing dllimport as was done before? This often happens in situations involving inline methods of templates, and I don't think it would be correct to export such inline functions. I also wouldn't want LTO to suddenly export a bunch of things that the native linker wouldn't export. By the way, this situation is covered by the LNK4049 and LNK4217 warnings in the Microsoft linker.

Here's an example of a situation where you might get accidental incorrect imports: https://gcc.godbolt.org/z/VAl5Kn

  void g(int);
  template <typename T>
  struct Foo {
    static void f() { g(sizeof(T)); }
  };
  // Uncomment Bar to see Foo<int>::f get imported
  //struct __declspec(dllimport) Bar : Foo<int> {};
  void h() { Foo<int>::f(); }

I don't think it would be correct to upgrade Foo<int>::f to dllexport.


Repository:
  rL LLVM

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D55627/new/

https://reviews.llvm.org/D55627