[PATCH] D45978: dllexport const variables must have external linkage.

[Aaron Ballman via Phabricator via cfe-commits]

aaron.ballman added a comment.

Can you add tests for C mode as well, as it seems the behavior differs there. Given:

  __declspec(dllexport) int const x = 3;
  __declspec(dllexport) const int y;
  extern int const z = 4;
  
  int main() {
    int a = x + y + z;
    return a;
  }

I get:

  C:\Users\aballman.GRAMMATECH\source\repos\ConsoleApplication1\ConsoleApplication1>cl -c ConsoleApplication1.cpp
  Microsoft (R) C/C++ Optimizing Compiler Version 19.16.27026.1 for x64
  Copyright (C) Microsoft Corporation.  All rights reserved.
  
  ConsoleApplication1.cpp
  ConsoleApplication1.cpp(2): error C2734: 'y': 'const' object must be initialized if not 'extern'
  
  C:\Users\aballman.GRAMMATECH\source\repos\ConsoleApplication1\ConsoleApplication1>cl -c /Tc ConsoleApplication1.cpp
  Microsoft (R) C/C++ Optimizing Compiler Version 19.16.27026.1 for x64
  Copyright (C) Microsoft Corporation.  All rights reserved.
  
  ConsoleApplication1.cpp
  
  C:\Users\aballman.GRAMMATECH\source\repos\ConsoleApplication1\ConsoleApplication1>dumpbin /symbols ConsoleApplication1.obj | grep External
  008 00000000 SECT3  notype       External     | x
  009 00000004 UNDEF  notype       External     | y
  00A 00000004 SECT3  notype       External     | z
  00D 00000000 SECT4  notype ()    External     | main

After commenting out the declaration and use of `y` and recompiling in C++ mode:

  C:\Users\aballman.GRAMMATECH\source\repos\ConsoleApplication1\ConsoleApplication1>dumpbin /symbols ConsoleApplication1.obj | grep External
  008 00000000 SECT3  notype       External     | ?z@@3HB (int const z)
  00B 00000000 SECT4  notype ()    External     | main



================
Comment at: test/Sema/dllexport-1.cpp:2
+// RUN: %clang_cc1 -triple i686-win32 -fsyntax-only -fms-extensions -verify %s
+// RUN: %clang_cc1 -triple x86_64-win32   -fsyntax-only -fms-extensions -verify -std=c++11 %s
+
----------------
Can remove some extra whitespace before `-fsyntax-only` (same is true in the other test as well).


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  https://reviews.llvm.org/D45978/new/

https://reviews.llvm.org/D45978