Decouple dllexport/dllimport from linkage

Representing dllexport/dllimport as distinct linkage types prevents using
these attributes on templates and inline functions.

Instead of introducing further mixed linkage types to include linkonce and
weak ODR, the old import/export linkage types are replaced with a new
separate visibility-like specifier:

  define available_externally dllimport void @f() {}
  @Var = dllexport global i32 1, align 4

Linkage for dllexported globals and functions is now equal to their linkage
without dllexport. Imported globals and functions must be either
declarations with external linkage, or definitions with
AvailableExternallyLinkage.

llvm-svn: 199218

1 files changed, 2 insertions, 2 deletions

diff --git a/llvm/include/llvm-c/Core.h b/llvm/include/llvm-c/Core.h
index 269869ef0da..a84a0313211 100644
--- a/llvm/include/llvm-c/Core.h
+++ b/llvm/include/llvm-c/Core.h
@@ -284,8 +284,8 @@ typedef enum {
   LLVMInternalLinkage,    /**< Rename collisions when linking (static
                                functions) */
   LLVMPrivateLinkage,     /**< Like Internal, but omit from symbol table */
-  LLVMDLLImportLinkage,   /**< Function to be imported from DLL */
-  LLVMDLLExportLinkage,   /**< Function to be accessible from DLL */
+  LLVMDLLImportLinkage,   /**< Obsolete */
+  LLVMDLLExportLinkage,   /**< Obsolete */
   LLVMExternalWeakLinkage,/**< ExternalWeak linkage description */
   LLVMGhostLinkage,       /**< Obsolete */
   LLVMCommonLinkage,      /**< Tentative definitions */