[PATCH] D137107: Allow MS extension: support of constexpr with __declspec(dllimport).

[Martin Storsjö via Phabricator via cfe-commits]

mstorsjo added a comment.

In D137107#3906439 <https://reviews.llvm.org/D137107#3906439>, @zahiraam wrote:

> Here is an even smaller test case.
> lib.cpp:
> __declspec(dllexport) int val=12;
>
> t1.cpp:
> int main () {
>
>   extern int _declspec(dllimport) val;
>   int& val_ref = val;
>   return val;
>
> }
> $ clang.exe -LD lib.cpp (this will create a.lib and a.exp)
> $ clang.exe t1.cpp -la
> $ ./a.exe
> This will result in a popup message: "The application was unable to start correctly ..."

What does `llvm-readobj --coff-imports a.exe` show here?

What environment are you running this in? `-LD` is a cl/clang-cl style option and can't be passed to the gnu-style interface of `clang.exe`.

When I try to follow these examples in cmd.exe, I get the following:

  >clang.exe -LD lib.cpp
     Creating library a.lib and object a.exp
  LINK : fatal error LNK1561: entry point must be defined
  clang: error: linker command failed with exit code 1561 (use -v to see invocation)

It looks to me like the way you're invoking the compiler here is creating the issue you're observing. This testcase works just fine for me when I build it like this:

  >clang-cl -LD lib.cpp
  >clang-cl t1.cpp -link lib.lib
  >t1.exe
  >echo %errorlevel%
  12


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https://reviews.llvm.org/D137107