[AArch64] Add support for dllimport of values and functions

Previously, the dllimport attribute did the right thing in terms
of treating it as a pointer to a value, but this makes sure the
names get mangled properly, and calls to such functions load the
function from the __imp_ pointer.

This is based on SVN r212431 and r212430 where the same was
implemented for ARM.

Differential Revision: https://reviews.llvm.org/D38530

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@316555 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 54 insertions, 0 deletions

diff --git a/test/CodeGen/AArch64/dllimport.ll b/test/CodeGen/AArch64/dllimport.ll
new file mode 100644
index 00000000000..fad049a54cd
--- /dev/null
+++ b/test/CodeGen/AArch64/dllimport.ll
@@ -0,0 +1,54 @@
+; RUN: llc -mtriple aarch64-unknown-windows-msvc -filetype asm -o - %s | FileCheck %s
+
+@var = external dllimport global i32
+@ext = external global i32
+declare dllimport i32 @external()
+declare i32 @internal()
+
+define i32 @get_var() {
+  %1 = load i32, i32* @var, align 4
+  ret i32 %1
+}
+
+; CHECK-LABEL: get_var
+; CHECK: adrp x8, __imp_var
+; CHECK: ldr x8, [x8, __imp_var]
+; CHECK: ldr w0, [x8]
+; CHECK: ret
+
+define i32 @get_ext() {
+  %1 = load i32, i32* @ext, align 4
+  ret i32 %1
+}
+
+; CHECK-LABEL: get_ext
+; CHECK: adrp x8, ext
+; CHECK: ldr w0, [x8, ext]
+; CHECK: ret
+
+define i32* @get_var_pointer() {
+  ret i32* @var
+}
+
+; CHECK-LABEL: get_var_pointer
+; CHECK: adrp x0, __imp_var
+; CHECK: ldr x0, [x0, __imp_var]
+; CHECK: ret
+
+define i32 @call_external() {
+  %call = tail call i32 @external()
+  ret i32 %call
+}
+
+; CHECK-LABEL: call_external
+; CHECK: adrp x0, __imp_external
+; CHECK: ldr x0, [x0, __imp_external]
+; CHECK: br x0
+
+define i32 @call_internal() {
+  %call = tail call i32 @internal()
+  ret i32 %call
+}
+
+; CHECK-LABEL: call_internal
+; CHECK: b internal