Merge pull request #41912 from hyp/unify2

Recommit: [cxx-interop] start to emitting a unified header file for a Swift module

Author: hyp

include/swift/AST/DiagnosticsFrontend.def

@@ -118,9 +118,7 @@ ERROR(error_mode_cannot_emit_dependencies,none,
 ERROR(error_mode_cannot_emit_reference_dependencies,none,
       "this mode does not support emitting reference dependency files", ())
 ERROR(error_mode_cannot_emit_header,none,
-      "this mode does not support emitting Objective-C headers", ())
-ERROR(error_mode_cannot_emit_cxx_header,none,
-      "this mode does not support emitting C++ headers", ())
+      "this mode does not support emitting Objective-C or C++ headers", ())
 ERROR(error_mode_cannot_emit_loaded_module_trace,none,
       "this mode does not support emitting the loaded module trace", ())
 ERROR(error_mode_cannot_emit_module,none,

include/swift/Basic/FileTypes.def

@@ -59,8 +59,7 @@ TYPE("raw-sib",             RawSIB,                    "sib",             "")
 TYPE("llvm-ir",             LLVM_IR,                   "ll",              "")
 TYPE("llvm-bc",             LLVM_BC,                   "bc",              "")
 TYPE("diagnostics",         SerializedDiagnostics,     "dia",             "")
-TYPE("objc-header",         ObjCHeader,                "h",               "")
-TYPE("cxx-header",          CXXHeader,                 "h",               "")
+TYPE("clang-header",        ClangHeader,               "h",               "")
 TYPE("swift-dependencies",  SwiftDeps,                 "swiftdeps",       "")
 TYPE("external-swift-dependencies", ExternalSwiftDeps,  "swiftdeps.external",  "")
 TYPE("remap",               Remapping,                 "remap",           "")

include/swift/Basic/SupplementaryOutputPaths.h

@@ -20,27 +20,17 @@
 
 namespace swift {
 struct SupplementaryOutputPaths {
-  /// The path to which we should emit an Objective-C header for the module.
+  /// The path to which we should emit a header file that exposes the Swift
+  /// declarations to C, Objective-C and C++ clients for the module.
   ///
   /// Currently only makes sense when the compiler has whole module knowledge.
   /// The modes for which it makes sense incuide both WMO and the "merge
   /// modules" job that happens after the normal compilation jobs. That's where
   /// the header is emitted in single-file mode, since it needs whole-module
   /// information.
   ///
-  /// \sa swift::printAsObjC
-  std::string ObjCHeaderOutputPath;
-
-  /// The path to which we should emit a C++ header for the module.
-  ///
-  /// Currently only makes sense when the compiler has whole module knowledge.
-  /// The modes for which it makes sense include both WMO and the "merge
-  /// modules" job that happens after the normal compilation jobs. That's where
-  /// the header is emitted in single-file mode, since it needs whole-module
-  /// information.
-  ///
-  /// \sa swift::printAsCXX
-  std::string CxxHeaderOutputPath;
+  /// \sa swift::printAsClangHeader
+  std::string ClangHeaderOutputPath;
 
   /// The path to which we should emit a serialized module.
   /// It is valid whenever there are any inputs.
@@ -170,10 +160,8 @@ struct SupplementaryOutputPaths {
 
   /// Apply a given function for each existing (non-empty string) supplementary output
   void forEachSetOutput(llvm::function_ref<void(const std::string&)> fn) const {
-    if (!ObjCHeaderOutputPath.empty())
-      fn(ObjCHeaderOutputPath);
-    if (!CxxHeaderOutputPath.empty())
-      fn(CxxHeaderOutputPath);
+    if (!ClangHeaderOutputPath.empty())
+      fn(ClangHeaderOutputPath);
     if (!ModuleOutputPath.empty())
       fn(ModuleOutputPath); 
     if (!ModuleSourceInfoOutputPath.empty())
@@ -209,9 +197,8 @@ struct SupplementaryOutputPaths {
   }
 
   bool empty() const {
-    return ObjCHeaderOutputPath.empty() && CxxHeaderOutputPath.empty() &&
-           ModuleOutputPath.empty() && ModuleDocOutputPath.empty() &&
-           DependenciesFilePath.empty() &&
+    return ClangHeaderOutputPath.empty() && ModuleOutputPath.empty() &&
+           ModuleDocOutputPath.empty() && DependenciesFilePath.empty() &&
            ReferenceDependenciesFilePath.empty() &&
            SerializedDiagnosticsPath.empty() && LoadedModuleTracePath.empty() &&
            TBDPath.empty() && ModuleInterfaceOutputPath.empty() &&

include/swift/Frontend/Frontend.h

@@ -392,8 +392,7 @@ class CompilerInvocation {
 
   std::string getOutputFilenameForAtMostOnePrimary() const;
   std::string getMainInputFilenameForDebugInfoForAtMostOnePrimary() const;
-  std::string getObjCHeaderOutputPathForAtMostOnePrimary() const;
-  std::string getCxxHeaderOutputPathForAtMostOnePrimary() const;
+  std::string getClangHeaderOutputPathForAtMostOnePrimary() const;
   std::string getModuleOutputPathForAtMostOnePrimary() const;
   std::string
   getReferenceDependenciesFilePathForPrimary(StringRef filename) const;

include/swift/Frontend/FrontendInputsAndOutputs.h

@@ -249,8 +249,7 @@ class FrontendInputsAndOutputs {
 
   bool hasDependenciesPath() const;
   bool hasReferenceDependenciesPath() const;
-  bool hasObjCHeaderOutputPath() const;
-  bool hasCxxHeaderOutputPath() const;
+  bool hasClangHeaderOutputPath() const;
   bool hasLoadedModuleTracePath() const;
   bool hasModuleOutputPath() const;
   bool hasModuleDocOutputPath() const;

include/swift/Frontend/FrontendOptions.h

@@ -378,6 +378,10 @@ class FrontendOptions {
   /// '.../lib/swift', otherwise '.../lib/swift_static'.
   bool UseSharedResourceFolder = true;
 
+  /// Indicates whether to expose all public declarations in the generated clang
+  /// header.
+  bool ExposePublicDeclsInClangHeader = false;
+
   /// \return true if the given action only parses without doing other compilation steps.
   static bool shouldActionOnlyParse(ActionType);
 

include/swift/Option/FrontendOptions.td

@@ -1031,4 +1031,9 @@ def skip_import_in_public_interface:
   HelpText<"Skip the import statement corresponding to a module name "
            "when printing the public interface.">;
 
+def clang_header_expose_public_decls:
+  Flag<["-"], "clang-header-expose-public-decls">,
+  HelpText<"Expose all public declarations in the generated clang header">,
+  Flags<[FrontendOption, HelpHidden]>;
+
 } // end let Flags = [FrontendOption, NoDriverOption, HelpHidden]

include/swift/Option/Options.td

@@ -532,13 +532,11 @@ def emit_objc_header_path : Separate<["-"], "emit-objc-header-path">,
          SupplementaryOutput]>,
   MetaVarName<"<path>">, HelpText<"Emit an Objective-C header file to <path>">;
 
-def emit_cxx_header : Flag<["-"], "emit-cxx-header">,
-  Flags<[FrontendOption, NoInteractiveOption, SupplementaryOutput]>,
-  HelpText<"Emit a C++ header file">;
-def emit_cxx_header_path : Separate<["-"], "emit-cxx-header-path">,
-  Flags<[FrontendOption, NoInteractiveOption, ArgumentIsPath,
+def emit_clang_header_path : Separate<["-"], "emit-clang-header-path">,
+  Flags<[FrontendOption, NoDriverOption, NoInteractiveOption, ArgumentIsPath,
          SupplementaryOutput]>,
-  MetaVarName<"<path>">, HelpText<"Emit a C++ header file to <path>">;
+  HelpText<"Emit an Objective-C and C++ header file to <path>">,
+  Alias<emit_objc_header_path>;
 
 def static : Flag<["-"], "static">,
   Flags<[FrontendOption, ModuleInterfaceOption, NoInteractiveOption]>,

include/swift/PrintAsClang/PrintAsClang.h

@@ -21,16 +21,19 @@ namespace swift {
   class ModuleDecl;
   class ValueDecl;
 
-  /// Print the Objective-C-compatible declarations in a module as a Clang
-  /// header.
+  /// Print the exposed declarations in a module into a Clang header.
   ///
-  /// Returns true on error.
-  bool printAsObjC(raw_ostream &out, ModuleDecl *M, StringRef bridgingHeader);
-
-  /// Print the C++-compatible declarations in a module as a Clang header.
+  /// The Objective-C compatible declarations are printed into a block that
+  /// ensures that those declarations are only usable when the header is
+  /// compiled in Objective-C mode.
+  /// The C++ compatible declarations are printed into a block that ensures
+  /// that those declarations are only usable when the header is compiled in
+  /// C++ mode.
   ///
   /// Returns true on error.
-  bool printAsCXX(raw_ostream &os, ModuleDecl *M);
+  bool printAsClangHeader(raw_ostream &out, ModuleDecl *M,
+                          StringRef bridgingHeader,
+                          bool ExposePublicDeclsInClangHeader);
 }
 
 #endif

lib/Basic/FileTypes.cpp

@@ -73,8 +73,7 @@ bool file_types::isTextual(ID Id) {
   case file_types::TY_ASTDump:
   case file_types::TY_RawSIL:
   case file_types::TY_LLVM_IR:
-  case file_types::TY_ObjCHeader:
-  case file_types::TY_CXXHeader:
+  case file_types::TY_ClangHeader:
   case file_types::TY_AutolinkFile:
   case file_types::TY_ImportedModules:
   case file_types::TY_TBD:
@@ -132,8 +131,7 @@ bool file_types::isAfterLLVM(ID Id) {
   case file_types::TY_Dependencies:
   case file_types::TY_ASTDump:
   case file_types::TY_RawSIL:
-  case file_types::TY_ObjCHeader:
-  case file_types::TY_CXXHeader:
+  case file_types::TY_ClangHeader:
   case file_types::TY_AutolinkFile:
   case file_types::TY_Image:
   case file_types::TY_dSYM:
@@ -183,8 +181,7 @@ bool file_types::isPartOfSwiftCompilation(ID Id) {
   case file_types::TY_LLVM_BC:
   case file_types::TY_Object:
   case file_types::TY_Dependencies:
-  case file_types::TY_ObjCHeader:
-  case file_types::TY_CXXHeader:
+  case file_types::TY_ClangHeader:
   case file_types::TY_AutolinkFile:
   case file_types::TY_PCH:
   case file_types::TY_ImportedModules: