llvm-project/clang/test/CodeGenCXX/cxx1z-inline-variables.cpp

// RUN: %clang_cc1 -std=c++1z %s -emit-llvm -o - -triple x86_64-linux-gnu | FileCheck %s

struct Q {
  // CHECK: @_ZN1Q1kE = linkonce_odr constant i32 5, comdat
  static constexpr int k = 5;
};
const int &r = Q::k;

int f();

// const does not imply internal linkage.
// CHECK: @external_inline = linkonce_odr constant i32 5, comdat
inline const int external_inline = 5;
const int &use1 = external_inline;

// static still does, though.
// CHECK: @_ZL15internal_inline = internal constant i32 5
static inline const int internal_inline = 5;
const int &use2 = internal_inline;

int a = f();
// CHECK: @b = linkonce_odr global i32 0, comdat
// CHECK: @_ZGV1b = linkonce_odr global i64 0, comdat($b)
inline int b = f();
int c = f();

// For compatibility with C++11 and C++14, an out-of-line declaration of a
// static constexpr local variable promotes the variable to weak_odr.
struct compat {
  static constexpr int a = 1;
  static constexpr int b = 2;
  static constexpr int c = 3;
  static inline constexpr int d = 4;
  static const int e = 5;
  static const int f = 6;
  static const int g = 7;
};
const int &compat_use_before_redecl = compat::b;
const int compat::a;
const int compat::b;
const int compat::c;
const int compat::d;
const int compat::e;
constexpr int compat::f;
constexpr inline int compat::g;
const int &compat_use_after_redecl1 = compat::c;
const int &compat_use_after_redecl2 = compat::d;
const int &compat_use_after_redecl3 = compat::g;
// CHECK-DAG: @_ZN6compat1bE = weak_odr constant i32 2
// CHECK-DAG: @_ZN6compat1aE = weak_odr constant i32 1
// CHECK-DAG: @_ZN6compat1cE = weak_odr constant i32 3
// CHECK-DAG: @_ZN6compat1dE = linkonce_odr constant i32 4
// CHECK-DAG: @_ZN6compat1eE = constant i32 5
// CHECK-DAG: @_ZN6compat1fE = weak_odr constant i32 6
// CHECK-DAG: @_ZN6compat1gE = linkonce_odr constant i32 7

template<typename T> struct X {
  static int a;
  static inline int b;
  static int c;
  static const int d;
  static int e;
};
// CHECK: @_ZN1XIiE1aE = linkonce_odr global i32 10
// CHECK: @_ZN1XIiE1bE = global i32 20
// CHECK-NOT: @_ZN1XIiE1cE
// CHECK: @_ZN1XIiE1dE = linkonce_odr constant i32 40
// CHECK: @_ZN1XIiE1eE = linkonce_odr global i32 50
template<> inline int X<int>::a = 10;
int &use3 = X<int>::a;
template<> int X<int>::b = 20;
template<> inline int X<int>::c = 30;
template<typename T> constexpr int X<T>::d = 40;
template<typename T> inline int X<T>::e = 50;
const int *use_x_int_d = &X<int>::d;
const int *use_x_int_e = &X<int>::e;

template<typename T> struct Y;
template<> struct Y<int> {
  static constexpr int a = 123;
  static constexpr int b = 456;
  static constexpr int c = 789;
};
// CHECK: @_ZN1YIiE1aE = weak_odr constant i32 123
constexpr int Y<int>::a;
// CHECK: @_ZN1YIiE1bE = linkonce_odr constant i32 456
const int &yib = Y<int>::b;
// CHECK-NOT: @_ZN1YIiE1cE

// CHECK-LABEL: define {{.*}}global_var_init
// CHECK: call i32 @_Z1fv

// CHECK-LABEL: define {{.*}}global_var_init
// CHECK-NOT: comdat
// CHECK-SAME: {{$}}
// CHECK: load atomic {{.*}} acquire
// CHECK: br
// CHECK: __cxa_guard_acquire(i64* @_ZGV1b)
// CHECK: br
// CHECK: call i32 @_Z1fv
// CHECK: __cxa_guard_release(i64* @_ZGV1b)

// CHECK-LABEL: define {{.*}}global_var_init
// CHECK: call i32 @_Z1fv

template<typename T> inline int d = f();
int e = d<int>;

// CHECK-LABEL: define {{.*}}global_var_init{{.*}}comdat
// CHECK: _ZGV1dIiE
// CHECK-NOT: __cxa_guard_acquire(i64* @_ZGV1b)
// CHECK: call i32 @_Z1fv
// CHECK-NOT: __cxa_guard_release(i64* @_ZGV1b)

namespace PR35599 {
struct Marker1 {};
struct Marker2 {};

template <typename>
struct Foo {
  struct Bar { Bar(); };
  inline static Bar bar;
};

void run() {
  // All we want here are ODR uses. Anything that requires that the type is
  // complete is uninteresting.
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wunused-value"
  Foo<Marker1>::bar;
#pragma clang diagnostic pop
  static_cast<void>(Foo<Marker2>::bar);
}

// CHECK-LABEL: define {{.*}}global_var_init{{.*}}comdat
// CHECK: call void @_ZN7PR355993FooINS_7Marker1EE3BarC1Ev
// CHECK-LABEL: define {{.*}}global_var_init{{.*}}comdat
// CHECK: call void @_ZN7PR355993FooINS_7Marker2EE3BarC1Ev
}