[c++2a] Implement semantic restrictions for 'export' declarations.

llvm-svn: 358932

10 files changed, 254 insertions, 29 deletions

diff --git a/clang/test/CXX/module/module.interface/Inputs/header.h b/clang/test/CXX/module/module.interface/Inputs/header.h
new file mode 100644
index 00000000000..f2e2cbb53c1
--- /dev/null
+++ b/clang/test/CXX/module/module.interface/Inputs/header.h
@@ -0,0 +1,3 @@
+extern int foo;
+namespace bar { extern int baz(); }
+static int baz;
diff --git a/clang/test/CXX/module/module.interface/p1.cpp b/clang/test/CXX/module/module.interface/p1.cpp
index 1eba8175de4..0947b81915e 100644
--- a/clang/test/CXX/module/module.interface/p1.cpp
+++ b/clang/test/CXX/module/module.interface/p1.cpp
@@ -23,15 +23,15 @@ namespace N {
 }
 
 #ifdef ERRORS
-namespace {
-  export int d1; // FIXME: invalid
+namespace { // expected-note 2{{anonymous namespace begins here}}
+  export int d1; // expected-error {{export declaration appears within anonymous namespace}}
   namespace X {
-    export int d2; // FIXME: invalid
+    export int d2; // expected-error {{export declaration appears within anonymous namespace}}
   }
 }
 
 export export int e; // expected-error {{within another export declaration}}
-export { export int f; } // expected-error {{within another export declaration}}
+export { export int f; } // expected-error {{within another export declaration}} expected-note {{export block begins here}}
 
 module :private; // expected-note {{private module fragment begins here}}
 export int priv; // expected-error {{export declaration cannot be used in a private module fragment}}
diff --git a/clang/test/CXX/module/module.interface/p2.cpp b/clang/test/CXX/module/module.interface/p2.cpp
new file mode 100644
index 00000000000..0a6f8c2aad5
--- /dev/null
+++ b/clang/test/CXX/module/module.interface/p2.cpp
@@ -0,0 +1,94 @@
+// RUN: rm -rf %t
+// RUN: mkdir -p %t
+// RUN: %clang_cc1 -std=c++2a -x c++-header %S/Inputs/header.h -emit-header-module -fmodule-name=FIXME -o %t/h.pcm
+// RUN: %clang_cc1 -std=c++2a %s -DX_INTERFACE -emit-module-interface -o %t/x.pcm
+// RUN: %clang_cc1 -std=c++2a %s -DY_INTERFACE -emit-module-interface -o %t/y.pcm
+// RUN: %clang_cc1 -std=c++2a %s -DINTERFACE -fmodule-file=%t/x.pcm -fmodule-file=%t/y.pcm -emit-module-interface -o %t/m.pcm
+// RUN: %clang_cc1 -std=c++2a %s -DIMPLEMENTATION -I%S/Inputs -fmodule-file=%t/h.pcm -fmodule-file=%t/m.pcm -verify
+// RUN: %clang_cc1 -std=c++2a %s -DUSER -I%S/Inputs -fmodule-file=%t/h.pcm -fmodule-file=%t/m.pcm -verify
+
+#if defined(X_INTERFACE)
+export module X;
+export int x;
+
+#elif defined(Y_INTERFACE)
+export module Y;
+export int y;
+
+#elif defined(INTERFACE)
+export module p2;
+export import X;
+import Y; // not exported
+
+namespace A {
+  int f();
+  export int g();
+  int h();
+  namespace inner {}
+}
+export namespace B {
+  namespace inner {}
+}
+namespace B {
+  int f();
+}
+namespace C {}
+namespace D { int f(); }
+export namespace D {}
+
+#elif defined(IMPLEMENTATION)
+module p2;
+import "header.h";
+
+// Per [basic.scope.namespace]/2.3, exportedness has no impact on visibility
+// within the same module.
+//
+// expected-no-diagnostics
+
+void use() {
+  A::f();
+  A::g();
+  A::h();
+  using namespace A::inner;
+
+  using namespace B;
+  using namespace B::inner;
+  B::f();
+  f();
+
+  using namespace C;
+
+  D::f();
+}
+
+int use_header() { return foo + bar::baz(); }
+
+#elif defined(USER)
+import p2;
+import "header.h";
+
+void use() {
+  // namespace A is implicitly exported by the export of A::g.
+  A::f(); // expected-error {{no member named 'f' in namespace 'A'}}
+  A::g();
+  A::h(); // expected-error {{no member named 'h' in namespace 'A'}}
+  using namespace A::inner; // expected-error {{expected namespace name}}
+
+  // namespace B and B::inner are explicitly exported
+  using namespace B;
+  using namespace B::inner;
+  B::f(); // expected-error {{no member named 'f' in namespace 'B'}}
+  f(); // expected-error {{undeclared identifier 'f'}}
+
+  // namespace C is not exported
+  using namespace C; // expected-error {{expected namespace name}}
+
+  // namespace D is exported, but D::f is not
+  D::f(); // expected-error {{no member named 'f' in namespace 'D'}}
+}
+
+int use_header() { return foo + bar::baz(); }
+
+#else
+#error unknown mode
+#endif
diff --git a/clang/test/CXX/module/module.interface/p3.cpp b/clang/test/CXX/module/module.interface/p3.cpp
new file mode 100644
index 00000000000..89c5e08f546
--- /dev/null
+++ b/clang/test/CXX/module/module.interface/p3.cpp
@@ -0,0 +1,54 @@
+// RUN: %clang_cc1 -std=c++2a %s -verify -pedantic-errors
+
+export module p3;
+
+namespace A { int ns_mem; }
+
+// An exported declaration shall declare at least one name.
+export; // expected-error {{empty declaration cannot be exported}}
+export static_assert(true); // expected-error {{static_assert declaration cannot be exported}}
+export using namespace A; // expected-error {{ISO C++20 does not permit using directive to be exported}}
+
+export { // expected-note 3{{export block begins here}}
+  ; // expected-error {{ISO C++20 does not permit an empty declaration to appear in an export block}}
+  static_assert(true); // expected-error {{ISO C++20 does not permit a static_assert declaration to appear in an export block}}
+  using namespace A; // expected-error {{ISO C++20 does not permit using directive to be exported}}
+}
+
+export struct {}; // expected-error {{must be class member}} expected-error {{GNU extension}}
+export struct {} struct_;
+export union {}; // expected-error {{must be declared 'static'}}
+export union {} union_;
+export enum {}; // expected-error {{does not declare anything}}
+export enum {} enum_;
+export enum E : int;
+export typedef int; // expected-error {{typedef requires a name}}
+export static union {}; // FIXME: this declaration is ill-formed even without the 'export'
+export asm(""); // expected-error {{asm declaration cannot be exported}}
+export namespace B = A;
+export using A::ns_mem;
+namespace A {
+  export using A::ns_mem;
+}
+export using Int = int;
+export extern "C++" {} // expected-error {{ISO C++20 does not permit a declaration that does not introduce any names to be exported}}
+export extern "C++" { extern "C" {} } // expected-error {{ISO C++20 does not permit a declaration that does not introduce any names to be exported}}
+export extern "C++" { extern "C" int extern_c; }
+export { // expected-note {{export block}}
+  extern "C++" int extern_cxx;
+  extern "C++" {} // expected-error {{ISO C++20 does not permit a declaration that does not introduce any names to be exported}}
+}
+export [[]]; // FIXME (bad diagnostic text): expected-error {{empty declaration cannot be exported}}
+export [[example::attr]]; // FIXME: expected-error {{empty declaration cannot be exported}} expected-warning {{unknown attribute 'attr'}}
+
+// [...] shall not declare a name with internal linkage
+export static int a; // expected-error {{declaration of 'a' with internal linkage cannot be exported}}
+export static int b(); // expected-error {{declaration of 'b' with internal linkage cannot be exported}}
+export namespace { int c; } // expected-error {{declaration of 'c' with internal linkage cannot be exported}}
+namespace { // expected-note {{here}}
+  export int d; // expected-error {{export declaration appears within anonymous namespace}}
+}
+export template<typename> static int e; // FIXME
+export template<typename> static int f(); // expected-error {{declaration of 'f' with internal linkage cannot be exported}}
+export const int k = 5;
+export static union { int n; }; // expected-error {{declaration of 'n' with internal linkage cannot be exported}}
diff --git a/clang/test/CXX/module/module.interface/p5.cpp b/clang/test/CXX/module/module.interface/p5.cpp
new file mode 100644
index 00000000000..c4299dc04fb
--- /dev/null
+++ b/clang/test/CXX/module/module.interface/p5.cpp
@@ -0,0 +1,89 @@
+// RUN: %clang_cc1 -std=c++2a %s -verify -pedantic-errors
+
+export module p5;
+
+int a;
+static int sa; // expected-note {{target}}
+void b();
+static void sb(); // expected-note {{target}}
+struct c {};
+enum d {};
+using e = int;
+using f = c;
+static union { int sg1, sg2; }; // expected-note {{target}}
+namespace NS {}
+
+template<typename> int ta;
+template<typename> static int sta;
+template<typename> void tb();
+template<typename> static void stb(); // expected-note {{target}}
+template<typename> struct tc {};
+template<typename> using te = int;
+template<typename> using tf = c;
+
+namespace UnnamedNS {
+  namespace {
+    int a; // expected-note {{target}}
+    static int sa; // expected-note {{target}}
+    void b(); // expected-note {{target}}
+    static void sb(); // expected-note {{target}}
+    struct c {}; // expected-note {{target}}
+    enum d {}; // expected-note {{target}}
+    using e = int;
+    using f = c;
+    static union { int sg1, sg2; }; // expected-note {{target}}
+    namespace NS {}
+
+    template<typename> int ta; // expected-note {{target}}
+    template<typename> static int sta; // expected-note {{target}}
+    template<typename> void tb(); // expected-note {{target}}
+    template<typename> static void stb(); // expected-note {{target}}
+    template<typename> struct tc {}; // expected-note {{target}}
+    template<typename> using te = int; // expected-note {{target}}
+    template<typename> using tf = c; // expected-note {{target}}
+  }
+}
+
+export { // expected-note 18{{here}}
+  using ::a;
+  using ::sa; // expected-error {{using declaration referring to 'sa' with internal linkage}}
+  using ::b;
+  using ::sb; // expected-error {{using declaration referring to 'sb' with internal linkage}}
+  using ::c;
+  using ::d;
+  using ::e;
+  using ::f;
+  using ::sg1; // expected-error {{using declaration referring to 'sg1' with internal linkage}}
+
+  using ::ta;
+  using ::sta; // FIXME {{using declaration referring to 'sta' with internal linkage}}
+  using ::tb;
+  using ::stb; // expected-error {{using declaration referring to 'stb' with internal linkage}}
+  using ::tc;
+  using ::te;
+  using ::tf;
+  namespace NS2 = ::NS;
+
+  namespace UnnamedNS {
+    using UnnamedNS::a; // expected-error {{internal linkage}}
+    using UnnamedNS::sa; // expected-error {{internal linkage}}
+    using UnnamedNS::b; // expected-error {{internal linkage}}
+    using UnnamedNS::sb; // expected-error {{internal linkage}}
+    using UnnamedNS::c; // expected-error {{internal linkage}}
+    using UnnamedNS::d; // expected-error {{internal linkage}}
+    using UnnamedNS::e; // ok
+    using UnnamedNS::f; // ok? using-declaration refers to alias-declaration,
+                        // which does not have linkage (even though that then
+                        // refers to a type that has internal linkage)
+    using UnnamedNS::sg1; // expected-error {{internal linkage}}
+
+    using UnnamedNS::ta; // expected-error {{internal linkage}}
+    using UnnamedNS::sta; // expected-error {{internal linkage}}
+    using UnnamedNS::tb; // expected-error {{internal linkage}}
+    using UnnamedNS::stb; // expected-error {{internal linkage}}
+    using UnnamedNS::tc; // expected-error {{internal linkage}}
+    using UnnamedNS::te; // expected-error {{internal linkage}}
+    using UnnamedNS::tf; // expected-error {{internal linkage}}
+    namespace NS2 = UnnamedNS::NS; // ok (wording bug?)
+  }
+}
diff --git a/clang/test/CXX/modules-ts/basic/basic.def.odr/p4/module.cpp b/clang/test/CXX/modules-ts/basic/basic.def.odr/p4/module.cpp
index ad03191363e..6eb5639d302 100644
--- a/clang/test/CXX/modules-ts/basic/basic.def.odr/p4/module.cpp
+++ b/clang/test/CXX/modules-ts/basic/basic.def.odr/p4/module.cpp
@@ -3,7 +3,6 @@
 
 // CHECK-DAG: @extern_var_exported = external {{(dso_local )?}}global
 // CHECK-DAG: @inline_var_exported = linkonce_odr {{(dso_local )?}}global
-// CHECK-DAG: @_ZW6ModuleE19static_var_exported = available_externally {{(dso_local )?}}global i32 0,
 // CHECK-DAG: @const_var_exported = available_externally {{(dso_local )?}}constant i32 3,
 //
 // CHECK-DAG: @_ZW6ModuleE25extern_var_module_linkage = external {{(dso_local )?}}global
@@ -21,7 +20,6 @@ void use() {
 
   (void)&extern_var_exported;
   (void)&inline_var_exported;
-  (void)&static_var_exported; // FIXME: Should not be exported.
   (void)&const_var_exported;
 
   // FIXME: This symbol should not be visible here.
diff --git a/clang/test/CXX/modules-ts/basic/basic.def.odr/p4/module.cppm b/clang/test/CXX/modules-ts/basic/basic.def.odr/p4/module.cppm
index 0f2c0db66e9..65861f84bae 100644
--- a/clang/test/CXX/modules-ts/basic/basic.def.odr/p4/module.cppm
+++ b/clang/test/CXX/modules-ts/basic/basic.def.odr/p4/module.cppm
@@ -11,7 +11,6 @@
 // can discard this global and its initializer (if any), and other TUs are not
 // permitted to run the initializer for this variable.
 // CHECK-DAG: @inline_var_exported = linkonce_odr {{(dso_local )?}}global
-// CHECK-DAG: @_ZW6ModuleE19static_var_exported = {{(dso_local )?}}global
 // CHECK-DAG: @const_var_exported = {{(dso_local )?}}constant
 //
 // CHECK-DAG: @_ZW6ModuleE25extern_var_module_linkage = external {{(dso_local )?}}global
@@ -58,32 +57,17 @@ void noninline_global_module() {
 export module Module;
 
 export {
-  // FIXME: These should be ill-formed: you can't export an internal linkage
-  // symbol, per [dcl.module.interface]p2.
-  // CHECK: define {{(dso_local )?}}void {{.*}}@_ZW6ModuleE22unused_static_exportedv
-  static void unused_static_exported() {}
-  // CHECK: define {{(dso_local )?}}void {{.*}}@_ZW6ModuleE20used_static_exportedv
-  static void used_static_exported() {}
-
   inline void unused_inline_exported() {}
   inline void used_inline_exported() {}
 
   extern int extern_var_exported;
   inline int inline_var_exported;
-  // FIXME: This should be ill-formed: you can't export an internal linkage
-  // symbol.
-  static int static_var_exported;
   const int const_var_exported = 3;
 
   // CHECK: define {{(dso_local )?}}void {{.*}}@_Z18noninline_exportedv
   void noninline_exported() {
-    used_static_exported();
-    // CHECK: define linkonce_odr {{.*}}@_Z20used_inline_exportedv
-    used_inline_exported();
-
     (void)&extern_var_exported;
     (void)&inline_var_exported;
-    (void)&static_var_exported;
     (void)&const_var_exported;
   }
 }
diff --git a/clang/test/CXX/modules-ts/basic/basic.def.odr/p4/user.cpp b/clang/test/CXX/modules-ts/basic/basic.def.odr/p4/user.cpp
index 97c69fa0bbe..d55e0637971 100644
--- a/clang/test/CXX/modules-ts/basic/basic.def.odr/p4/user.cpp
+++ b/clang/test/CXX/modules-ts/basic/basic.def.odr/p4/user.cpp
@@ -3,7 +3,6 @@
 
 // CHECK-DAG: @extern_var_exported = external {{(dso_local )?}}global
 // CHECK-DAG: @inline_var_exported = linkonce_odr {{(dso_local )?}}global
-// CHECK-DAG: @_ZW6ModuleE19static_var_exported = available_externally {{(dso_local )?}}global i32 0
 // CHECK-DAG: @const_var_exported = available_externally {{(dso_local )?}}constant i32 3
 
 import Module;
@@ -16,7 +15,6 @@ void use() {
 
   (void)&extern_var_exported;
   (void)&inline_var_exported;
-  (void)&static_var_exported;
   (void)&const_var_exported;
 
   // Module-linkage declarations are not visible here.
diff --git a/clang/test/SemaCXX/anonymous-union-export.cpp b/clang/test/SemaCXX/anonymous-union-export.cpp
index 1d83d809f52..689c6b9f17e 100644
--- a/clang/test/SemaCXX/anonymous-union-export.cpp
+++ b/clang/test/SemaCXX/anonymous-union-export.cpp
@@ -1,6 +1,7 @@
 // RUN: %clang_cc1 -std=c++17 -fmodules-ts -emit-obj -verify -o %t.pcm %s
 
 export module M;
-export {
-    union { bool a; }; // expected-error{{anonymous unions at namespace or global scope must be declared 'static'}}
+export { // expected-note 2{{export block begins here}}
+    union { bool a; }; // expected-error {{anonymous unions at namespace or global scope must be declared 'static'}} expected-error {{declaration of 'a' with internal linkage cannot be exported}}
+    static union { bool a; }; // expected-error {{declaration of 'a' with internal linkage cannot be exported}}
 }
diff --git a/clang/test/SemaCXX/modules-ts.cppm b/clang/test/SemaCXX/modules-ts.cppm
index c07ee82e313..1081995c586 100644
--- a/clang/test/SemaCXX/modules-ts.cppm
+++ b/clang/test/SemaCXX/modules-ts.cppm
@@ -49,8 +49,12 @@ int use_a = a; // expected-error {{declaration of 'a' must be imported from modu
 import foo;
 
 export {} // expected-error {{export declaration cannot be empty}}
-export { ; }
-export { static_assert(true); }
+export { // expected-note {{begins here}}
+  ; // expected-warning {{ISO C++20 does not permit an empty declaration to appear in an export block}}
+}
+export { // expected-note {{begins here}}
+  static_assert(true); // expected-warning {{ISO C++20 does not permit a static_assert declaration to appear in an export block}}
+}
 
 int use_b = b;
 int use_n = n; // FIXME: this should not be visible, because it is not exported
@@ -74,7 +78,7 @@ struct S {
 // language rules right now, but (per personal correspondence between zygoloid
 // and gdr) is the intent.
 #if TEST == 1
-export {
+export { // expected-note {{export block begins here}}
   extern "C++" {
     namespace NestedExport {
       export { // expected-error {{appears within another export}}