[PATCH] D123837: [C++20] [Modules] Judge isInCurrentModule currently

[Chuanqi Xu via Phabricator via cfe-commits]

ChuanqiXu created this revision.
ChuanqiXu added reviewers: iains, rsmith, clang-language-wg.
ChuanqiXu added a project: clang.
Herald added a subscriber: dexonsmith.
Herald added a project: All.
ChuanqiXu requested review of this revision.
Herald added a subscriber: cfe-commits.

Now the implementation would accept following code:

  //--- impl.cppm
  module M:impl;
  class A {};
  
  //--- M.cppm
  export module M;
  import :impl;
  
  //--- Use.cpp
  import M;
  void test() {
      A a; // Expected error. A is not visible here.
  }

which is clearly wrong.  The root cause is the implementation of `isInCurrentModule` would return true if the module is a partition! So in the above example, although Use.cpp is not a module unit, `isInCurrentModule ` would still return true when the compiler tries to see if the owning module of `A` is the current module. I believe this is an oversight. And we could fix it simply by comparing the primary module name.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D123837

Files:
  clang/include/clang/Basic/Module.h
  clang/lib/Sema/SemaLookup.cpp
  clang/test/CXX/module/module.import/p2.cpp


Index: clang/test/CXX/module/module.import/p2.cpp
===================================================================
--- /dev/null
+++ clang/test/CXX/module/module.import/p2.cpp
@@ -0,0 +1,21 @@
+// RUN: rm -rf %t
+// RUN: mkdir -p %t
+// RUN: split-file %s %t
+// RUN: %clang_cc1 -std=c++20 %t/impl.cppm -emit-module-interface -o %t/M-impl.pcm
+// RUN: %clang_cc1 -std=c++20 %t/M.cppm -emit-module-interface -fprebuilt-module-path=%t -o %t/M.pcm
+// RUN: %clang_cc1 -std=c++20 %t/Use.cpp -fprebuilt-module-path=%t -verify -fsyntax-only
+
+//--- impl.cppm
+module M:impl;
+class A {};
+
+//--- M.cppm
+export module M;
+import :impl;
+export A f();
+
+//--- Use.cpp
+import M;
+void test() {
+    A a; // expected-error {{unknown type name 'A'}}
+}
Index: clang/lib/Sema/SemaLookup.cpp
===================================================================
--- clang/lib/Sema/SemaLookup.cpp
+++ clang/lib/Sema/SemaLookup.cpp
@@ -1561,12 +1561,11 @@
 static bool isInCurrentModule(const Module *M, const LangOptions &LangOpts) {
   // If M is the global module fragment of a module that we've not yet finished
   // parsing, then it must be part of the current module.
-  // If it's a partition, then it must be visible to an importer (since only
-  // another partition or the named module can import it).
-  return M->getTopLevelModuleName() == LangOpts.CurrentModule ||
-         (M->Kind == Module::GlobalModuleFragment && !M->Parent) ||
-         M->Kind == Module::ModulePartitionInterface ||
-         M->Kind == Module::ModulePartitionImplementation;
+  if (M->isGlobalModule() && !M->Parent)
+    return true;
+
+  return M->getPrimaryModuleInterfaceName() ==
+         Module::getPrimaryModuleInterfaceName(LangOpts.CurrentModule);
 }
 
 bool Sema::hasVisibleMergedDefinition(NamedDecl *Def) {
Index: clang/include/clang/Basic/Module.h
===================================================================
--- clang/include/clang/Basic/Module.h
+++ clang/include/clang/Basic/Module.h
@@ -534,13 +534,13 @@
     return Kind == ModuleInterfaceUnit || isModulePartition();
   }
 
+  static StringRef getPrimaryModuleInterfaceName(StringRef Name) {
+    return Name.split(':').first;
+  }
+
   /// Get the primary module interface name from a partition.
   StringRef getPrimaryModuleInterfaceName() const {
-    if (isModulePartition()) {
-      auto pos = Name.find(':');
-      return StringRef(Name.data(), pos);
-    }
-    return Name;
+    return getPrimaryModuleInterfaceName(Name);
   }
 
   /// Retrieve the full name of this module, including the path from


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