llvm-capstone/clang/test/Modules/export-language-linkage.cppm
Chuanqi Xu bf52ead24c [C++20] [Modules] Support to export declarations in language linkage
Close https://github.com/llvm/llvm-project/issues/60405

See the discussion in the above link for the background.

What the patch does:
- Rename `Module::ModuleKind::GlobalModuleFragment` to
  `Module::ModuleKind::ExplicitGlobalModuleFragment`.
- Add another module kind `ImplicitGlobalModuleFragment` to
  `ModuleKind`.
- Create an implicit global module fragment for the language linkage
  declarations inside a module purview.
    - If the language linkage lives inside the scope of an export decl,
      the created modules is marked as exported to outer modules.
- In fact, Sema will only create at most 2 implicit global module
  fragments to avoid creating a lot of unnecessary modules in the edging
case.

Reviewed By: iains

Differential Revision: https://reviews.llvm.org/D144367
2023-03-03 10:31:48 +08:00

53 lines
1.4 KiB
C++

// RUN: rm -rf %t
// RUN: split-file %s %t
// RUN: cd %t
//
// RUN: %clang_cc1 -std=c++20 %t/a.cppm -emit-module-interface -o %t/a.pcm
// RUN: %clang_cc1 -std=c++20 %t/b.cpp -fmodule-file=a=%t/a.pcm -fsyntax-only -verify
// RUN: %clang_cc1 -std=c++20 %t/c.cppm -fsyntax-only -verify
// RUN: %clang_cc1 -module-file-info %t/a.pcm | FileCheck %t/a.cppm
//--- a.cppm
export module a;
export extern "C++" int foo() { return 43; }
export extern "C++" {
int a();
int b();
int c();
}
export {
extern "C++" void f1();
extern "C++" void f2();
extern "C++" void f3();
}
extern "C++" void unexported();
// CHECK: Sub Modules:
// CHECK-NEXT: Implicit Module Fragment '<exported implicit global>'
// CHECK-NEXT: Implicit Module Fragment '<implicit global>'
//--- b.cpp
import a;
int use() {
a();
b();
c();
f1();
f2();
f3();
unexported(); // expected-error {{missing '#include'; 'unexported' must be declared before it is used}}
// expected-note@a.cppm:15 {{declaration here is not visible}}
return foo();
}
//--- c.cppm
export module c;
extern "C++" {
// We can't use `export` in an unnamed module.
export int f(); // expected-error {{export declaration can only be used within a module purview}}
}
extern "C++" export int g(); // expected-error {{export declaration can only be used within a module purview}}