[CIR][cir-link] Add simple cir function linker test

Author: xlauko

clang/test/CIR/Tools/cir-link/function-a.cir

@@ -0,0 +1,27 @@
+// RUN: cir-link -sort-symbols -split-input-file %s | FileCheck %s
+
+// CHECK:      cir.func @f1() {
+// CHECK-NEXT:   cir.return
+// CHECK-NEXT: }
+
+// CHECK:      cir.func @f2() {
+// CHECK-NEXT:   cir.call @f1() : () -> ()
+// CHECK-NEXT:   cir.return
+// CHECK-NEXT: }
+
+module {
+  cir.func private @f1()
+
+  cir.func @f2() {
+    cir.call @f1() : () -> ()
+    cir.return
+  }
+}
+
+// -----
+
+module {
+  cir.func @f1() {
+    cir.return
+  }
+}

clang/test/CMakeLists.txt

@@ -86,6 +86,7 @@ list(APPEND CLANG_TEST_DEPS
 
 if(CLANG_ENABLE_CIR)
   list(APPEND CLANG_TEST_DEPS
+    cir-link
     cir-opt
     cir-translate
     mlir-translate

clang/test/lit.cfg.py

@@ -86,6 +86,7 @@
 tools = [
     "apinotes-test",
     "c-index-test",
+    "cir-link",
     "cir-opt",
     "cir-translate",
     "clang-diff",