Use aliases for more constructors and destructors.

With this patch we produce alias for cases like

template<typename T>
struct foobar {
  foobar() {
  }
};
template struct foobar<void>;

We just have to be careful to produce the same aliases in every TU because
of comdats.

llvm-svn: 194000

1 files changed, 62 insertions, 0 deletions

diff --git a/clang/test/CodeGenCXX/ctor-dtor-alias.cpp b/clang/test/CodeGenCXX/ctor-dtor-alias.cpp
new file mode 100644
index 00000000000..e658522d799
--- /dev/null
+++ b/clang/test/CodeGenCXX/ctor-dtor-alias.cpp
@@ -0,0 +1,62 @@
+// RUN: %clang_cc1 %s -triple x86_64-linux -emit-llvm -o - -mconstructor-aliases | FileCheck %s
+
+namespace test1 {
+// test that we produce an alias when the destructor is weak_odr
+
+// CHECK-DAG: @_ZN5test16foobarIvEC1Ev = alias weak_odr void (%"struct.test1::foobar"*)* @_ZN5test16foobarIvEC2Ev
+// CHECK-DAG: define weak_odr void @_ZN5test16foobarIvEC2Ev(
+template <typename T> struct foobar {
+  foobar() {}
+};
+
+template struct foobar<void>;
+}
+
+namespace test2 {
+// test that we produce an alias when the destrucor is linkonce_odr. Note that
+// the alias itself is weak_odr to make sure we don't get a translation unit
+// with just _ZN5test26foobarIvEC2Ev in it.
+
+// CHECK-DAG: @_ZN5test26foobarIvEC1Ev = alias weak_odr void (%"struct.test2::foobar"*)* @_ZN5test26foobarIvEC2Ev
+// CHECK-DAG: define linkonce_odr void @_ZN5test26foobarIvEC2Ev(
+void g();
+template <typename T> struct foobar {
+  foobar() { g(); }
+};
+foobar<void> x;
+}
+
+namespace test3 {
+// test that these alias are internal.
+
+// CHECK-DAG: @_ZN5test312_GLOBAL__N_11AD1Ev = alias internal void (%"struct.test3::<anonymous namespace>::A"*)* @_ZN5test312_GLOBAL__N_11AD2Ev
+// CHECK-DAG: @_ZN5test312_GLOBAL__N_11BD2Ev = alias internal bitcast (void (%"struct.test3::<anonymous namespace>::A"*)* @_ZN5test312_GLOBAL__N_11AD2Ev to void (%"struct.test3::<anonymous namespace>::B"*)*)
+// CHECK-DAG: @_ZN5test312_GLOBAL__N_11BD1Ev = alias internal void (%"struct.test3::<anonymous namespace>::B"*)* @_ZN5test312_GLOBAL__N_11BD2Ev
+// CHECK-DAG: define internal void @_ZN5test312_GLOBAL__N_11AD2Ev(
+namespace {
+struct A {
+  ~A() {}
+};
+
+struct B : public A {};
+}
+
+B x;
+}
+
+namespace test4 {
+  // Test that we don't produce aliases from B to A. We cannot because we cannot
+  // guarantee that they will be present in every TU.
+
+  // CHECK-DAG: @_ZN5test41BD1Ev = alias weak_odr void (%"struct.test4::B"*)* @_ZN5test41BD2Ev
+  // CHECK-DAG: define linkonce_odr void @_ZN5test41BD2Ev(
+  // CHECK-DAG: @_ZN5test41AD1Ev = alias weak_odr void (%"struct.test4::A"*)* @_ZN5test41AD2Ev
+  // CHECK-DAG: define linkonce_odr void @_ZN5test41AD2Ev(
+  struct A {
+    virtual ~A() {}
+  };
+  struct B : public A{
+    ~B() {}
+  };
+  B X;
+}