Allow TLS vars in dllimport/export functions; only inline dllimport functions when safe (PR24593)

This patch does two things:

1) Don't error about dllimport/export on thread-local static local variables.
   We put those attributes on static locals in dllimport/export functions
   implicitly in case the function gets inlined. Now, for TLS variables this
   is a problem because we can't import such variables, but it's a benign
   problem becase:

2) Make sure we never inline a dllimport function TLS static locals. In fact,
   never inline a dllimport function that references a non-imported function
   or variable (because these are not defined in the importing library). This
   seems to match MSVC's behaviour.

Differential Revision: http://reviews.llvm.org/D12422

llvm-svn: 246338

1 files changed, 12 insertions, 0 deletions

diff --git a/clang/test/SemaCXX/dllimport.cpp b/clang/test/SemaCXX/dllimport.cpp
index 2fa10756da4..f17c2e22414 100644
--- a/clang/test/SemaCXX/dllimport.cpp
+++ b/clang/test/SemaCXX/dllimport.cpp
@@ -93,6 +93,18 @@ __declspec(dllimport) auto InternalAutoTypeGlobal = Internal(); // expected-erro
 
 // Thread local variables are invalid.
 __declspec(dllimport) __thread int ThreadLocalGlobal; // expected-error{{'ThreadLocalGlobal' cannot be thread local when declared 'dllimport'}}
+inline void InlineWithThreadLocal() {
+  static __declspec(dllimport) __thread int ThreadLocalGlobal; // expected-error{{'ThreadLocalGlobal' cannot be thread local when declared 'dllimport'}}
+}
+
+// But if they're in a dllimported function, it's OK because we will not inline the function.
+// This doesn't work on MinGW, because there, dllimport on the inline function is ignored.
+#ifndef GNU
+inline void __declspec(dllimport) ImportedInlineWithThreadLocal() {
+  static __declspec(dllimport) __thread int OK1; // no-error
+  static __thread int OK2; // no-error
+}
+#endif
 
 // Import in local scope.
 __declspec(dllimport) float LocalRedecl1; // expected-note{{previous declaration is here}}