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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199218 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 59 insertions, 0 deletions

diff --git a/test/CodeGen/X86/dllimport.ll b/test/CodeGen/X86/dllimport.ll
new file mode 100644
index 0000000000..695bfce821
--- /dev/null
+++ b/test/CodeGen/X86/dllimport.ll
@@ -0,0 +1,59 @@
+; RUN: llc -mtriple i386-pc-win32 < %s | FileCheck %s
+; RUN: llc -mtriple i386-pc-mingw32 < %s | FileCheck %s
+;
+; RUN: llc -mtriple i386-pc-mingw32 -O0 < %s | FileCheck %s -check-prefix=FAST
+; PR6275
+;
+; RUN: opt -mtriple i386-pc-win32 -std-compile-opts -S < %s | FileCheck %s -check-prefix=OPT
+
+@Var1 = external dllimport global i32
+@Var2 = available_externally dllimport unnamed_addr constant i32 1
+
+declare dllimport void @fun()
+
+define available_externally dllimport void @inline1() {
+	ret void
+}
+
+define available_externally dllimport void @inline2() alwaysinline {
+	ret void
+}
+
+declare dllimport x86_stdcallcc void @stdfun() nounwind
+declare dllimport x86_fastcallcc void @fastfun() nounwind
+declare dllimport x86_thiscallcc void @thisfun() nounwind
+
+declare void @dummy(...)
+
+define void @use() nounwind {
+; CHECK:     calll *__imp__fun
+; FAST:      movl  __imp__fun, [[R:%[a-z]{3}]]
+; FAST-NEXT: calll *[[R]]
+  call void @fun()
+
+; CHECK: calll *__imp__inline1
+; CHECK: calll *__imp__inline2
+  call void @inline1()
+  call void @inline2()
+
+; CHECK: calll *__imp__stdfun@0
+; CHECK: calll *__imp_@fastfun@0
+; CHECK: calll *__imp__thisfun
+  call void @stdfun()
+  call void @fastfun()
+  call void @thisfun()
+
+; available_externally uses go away
+; OPT-NOT: call void @inline1()
+; OPT-NOT: call void @inline2()
+; OPT-NOT: load i32* @Var2
+; OPT: call void (...)* @dummy(i32 %1, i32 1)
+
+; CHECK-DAG: movl __imp__Var1, [[R1:%[a-z]{3}]]
+; CHECK-DAG: movl __imp__Var2, [[R2:%[a-z]{3}]]
+  %1 = load i32* @Var1
+  %2 = load i32* @Var2
+  call void(...)* @dummy(i32 %1, i32 %2)
+
+  ret void
+}