Implement __attribute__((internal_linkage)).

The attrubite is applicable to functions and variables and changes
the linkage of the subject to internal.

This is the same functionality as C-style "static", but applicable to
class methods; and the same as anonymouns namespaces, but can apply
to individual methods of a class.

Following the proposal in
http://lists.llvm.org/pipermail/cfe-dev/2015-October/045580.html

llvm-svn: 252648

1 files changed, 79 insertions, 0 deletions

diff --git a/clang/test/CodeGenCXX/attribute_internal_linkage.cpp b/clang/test/CodeGenCXX/attribute_internal_linkage.cpp
new file mode 100644
index 00000000000..21cd44e916f
--- /dev/null
+++ b/clang/test/CodeGenCXX/attribute_internal_linkage.cpp
@@ -0,0 +1,79 @@
+// RUN: %clang_cc1 -triple x86_64-unknown-unknown -std=c++11 -emit-llvm -o - %s | FileCheck %s
+
+__attribute__((internal_linkage)) void f() {}
+// CHECK-DAG: define internal void @_ZL1fv
+
+class A {
+public:
+  static int y __attribute__((internal_linkage));
+  static int y2 [[clang::internal_linkage]];
+// CHECK-DAG: @_ZN1A1yE = internal global
+// CHECK-DAG: @_ZN1A2y2E = internal global
+  void f1() __attribute__((internal_linkage));
+// CHECK-DAG: define internal void @_ZN1A2f1Ev
+  void f2() __attribute__((internal_linkage)) {}
+// CHECK-DAG: define internal void @_ZN1A2f2Ev
+  static void f4() __attribute__((internal_linkage)) {}
+// CHECK-DAG: define internal void @_ZN1A2f4Ev
+  A() __attribute__((internal_linkage)) {}
+// CHECK-DAG: define internal void @_ZN1AC1Ev
+// CHECK-DAG: define internal void @_ZN1AC2Ev
+  ~A() __attribute__((internal_linkage)) {}
+// CHECK-DAG: define internal void @_ZN1AD1Ev
+// CHECK-DAG: define internal void @_ZN1AD2Ev
+};
+
+int A::y;
+int A::y2;
+
+void A::f1() {
+}
+
+// Forward declaration w/o an attribute.
+class B;
+
+// Internal_linkage on a class affects all its members.
+class __attribute__((internal_linkage)) B {
+public:
+  B() {}
+  // CHECK-DAG: define internal void @_ZNL1BC1Ev
+  // CHECK-DAG: define internal void @_ZNL1BC2Ev
+  ~B() {}
+  // CHECK-DAG: define internal void @_ZNL1BD1Ev
+  // CHECK-DAG: define internal void @_ZNL1BD2Ev
+  void f() {};
+  // CHECK-DAG: define internal void @_ZNL1B1fEv
+  static int x;
+  // CHECK-DAG: @_ZNL1B1xE = internal global
+};
+
+int B::x;
+
+// Forward declaration with the attribute.
+class __attribute__((internal_linkage)) C;
+class C {
+public:
+  static int x;
+  // CHECK-DAG: @_ZNL1C1xE = internal global
+};
+
+int C::x;
+
+__attribute__((internal_linkage)) void g();
+void g() {}
+// CHECK-DAG: define internal void @_ZL1gv()
+
+void use() {
+  A a;
+  a.f1();
+  a.f2();
+  A::f4();
+  f();
+  int &Y = A::y;
+  int &Y2 = A::y2;
+  B b;
+  b.f();
+  int &XX2 = B::x;
+  g();
+  int &XX3 = C::x;
+}