Merge pull request #76269 from xymus/public-module-name

Diagnostics: Intro the public module name concept to hide support modules from clients

Author: xymus

include/swift/AST/FileUnit.h

@@ -335,6 +335,12 @@ class FileUnit : public DeclContext, public ASTAllocated<FileUnit> {
     return getParentModule()->getRealName().str();
   }
 
+  /// Returns the public facing name of this module, only if it is set
+  /// explicitly.
+  virtual StringRef getPublicModuleName() const {
+    return {};
+  }
+
   SWIFT_DEBUG_DUMPER(dumpDisplayDecls());
   SWIFT_DEBUG_DUMPER(dumpTopLevelDecls());
 

include/swift/AST/Module.h

@@ -243,6 +243,8 @@ class ModuleDecl
   /// Module name to use when referenced in clients module interfaces.
   mutable Identifier ExportAsName;
 
+  mutable Identifier PublicModuleName;
+
 public:
   /// Produces the components of a given module's full name in reverse order.
   ///
@@ -502,6 +504,21 @@ class ModuleDecl
     ExportAsName = name;
   }
 
+  /// Public facing name for this module in diagnostics and documentation.
+  ///
+  /// This always returns a valid name as it defaults to the module name if
+  /// no public module name is set.
+  ///
+  /// If `onlyIfImported`, return the normal module name when the module
+  /// corresponding to the public module name isn't imported. Users working
+  /// in between both modules will then see the normal module name,
+  /// this may be more useful for diagnostics at that level.
+  Identifier getPublicModuleName(bool onlyIfImported) const;
+
+  void setPublicModuleName(Identifier name) {
+    PublicModuleName = name;
+  }
+
   /// Retrieve the actual module name of an alias used for this module (if any).
   ///
   /// For example, if '-module-alias Foo=Bar' is passed in when building the main module,

include/swift/Frontend/FrontendOptions.h

@@ -70,6 +70,9 @@ class FrontendOptions {
   /// Module name to use when referenced in clients module interfaces.
   std::string ExportAsName;
 
+  /// The public facing name of the module to build.
+  std::string PublicModuleName;
+
   /// Arguments which should be passed in immediate mode.
   std::vector<std::string> ImmediateArgv;
 

include/swift/Option/Options.td

@@ -586,6 +586,9 @@ def package_name : Separate<["-"], "package-name">,
 def export_as : Separate<["-"], "export-as">,
   Flags<[FrontendOption, ModuleInterfaceOption]>,
   HelpText<"Module name to use when referenced in clients module interfaces">;
+def public_module_name : Separate<["-"], "public-module-name">,
+  Flags<[FrontendOption, ModuleInterfaceOptionIgnorable]>,
+  HelpText<"Public facing module name to use in diagnostics and documentation">;
 
 def emit_module : Flag<["-"], "emit-module">,
   Flags<[FrontendOption, NoInteractiveOption, SupplementaryOutput]>,

include/swift/Serialization/SerializedModuleLoader.h

@@ -531,6 +531,8 @@ class SerializedASTFile final : public LoadedFile {
 
   virtual StringRef getExportedModuleName() const override;
 
+  virtual StringRef getPublicModuleName() const override;
+
   ValueDecl *getMainDecl() const override;
 
   bool hasEntryPoint() const override;

include/swift/Serialization/Validation.h

@@ -129,6 +129,7 @@ class ExtendedValidationInfo {
   StringRef ModuleABIName;
   StringRef ModulePackageName;
   StringRef ExportAsName;
+  StringRef PublicModuleName;
   CXXStdlibKind CXXStdlib;
   struct {
     unsigned ArePrivateImportsEnabled : 1;
@@ -230,6 +231,9 @@ class ExtendedValidationInfo {
   StringRef getModulePackageName() const { return ModulePackageName; }
   void setModulePackageName(StringRef name) { ModulePackageName = name; }
 
+  StringRef getPublicModuleName() const { return PublicModuleName; }
+  void setPublicModuleName(StringRef name) { PublicModuleName = name; }
+
   StringRef getExportAsName() const { return ExportAsName; }
   void setExportAsName(StringRef name) { ExportAsName = name; }
 

lib/AST/DiagnosticEngine.cpp

@@ -847,7 +847,9 @@ static void formatDiagnosticArgument(StringRef Modifier,
     // Figure out the name we want to print.
     DeclName name;
     if (includeName) {
-      if (auto VD = dyn_cast<ValueDecl>(D))
+      if (auto MD = dyn_cast<ModuleDecl>(D))
+        name = MD->getPublicModuleName(/*onlyIfImported=*/true);
+      else if (auto VD = dyn_cast<ValueDecl>(D))
         name = VD->getName();
       else if (auto PGD = dyn_cast<PrecedenceGroupDecl>(D))
         name = PGD->getName();
@@ -1419,7 +1421,9 @@ DiagnosticEngine::diagnosticInfoForDiagnostic(const Diagnostic &diagnostic) {
           // build the name of the buffer.
           SmallVector<StringRef, 4> nameComponents;
           while (dc) {
-            nameComponents.push_back(cast<ModuleDecl>(dc)->getName().str());
+            auto publicName = cast<ModuleDecl>(dc)->
+                                getPublicModuleName(/*onlyIfImported*/true);
+            nameComponents.push_back(publicName.str());
             dc = dc->getParent();
           }
 

lib/AST/Module.cpp

@@ -1922,6 +1922,19 @@ ImportedModule::removeDuplicates(SmallVectorImpl<ImportedModule> &imports) {
   imports.erase(last, imports.end());
 }
 
+Identifier ModuleDecl::getPublicModuleName(bool onlyIfImported) const {
+  if (!PublicModuleName.empty()) {
+    if (!onlyIfImported)
+      return PublicModuleName;
+
+    bool publicModuleIsImported =
+      getASTContext().getModuleByIdentifier(PublicModuleName);
+    if (publicModuleIsImported)
+      return PublicModuleName;
+  }
+  return getName();
+}
+
 Identifier ModuleDecl::getRealName() const {
   // This will return the real name for an alias (if used) or getName()
   return getASTContext().getRealModuleName(getName());

lib/Frontend/ArgsToFrontendOptionsConverter.cpp

@@ -288,6 +288,9 @@ bool ArgsToFrontendOptionsConverter::convert(
       Opts.ExportAsName = exportAs;
   }
 
+  if (const Arg *A = Args.getLastArg(OPT_public_module_name))
+    Opts.PublicModuleName = A->getValue();
+
   // This must be called after computing module name, module abi name,
   // and module link name. If computing module aliases is unsuccessful,
   // return early.

lib/Frontend/Frontend.cpp

@@ -1465,6 +1465,10 @@ ModuleDecl *CompilerInstance::getMainModule() const {
       MainModule->setExportAsName(getASTContext().getIdentifier(
           Invocation.getFrontendOptions().ExportAsName));
     }
+    if (!Invocation.getFrontendOptions().PublicModuleName.empty()) {
+      MainModule->setPublicModuleName(getASTContext().getIdentifier(
+          Invocation.getFrontendOptions().PublicModuleName));
+    }
     if (Invocation.getFrontendOptions().EnableLibraryEvolution)
       MainModule->setResilienceStrategy(ResilienceStrategy::Resilient);
     if (Invocation.getLangOptions().isSwiftVersionAtLeast(6))