[Frontend] Add a new -emit-interface-path option

include/swift/AST/DiagnosticsFrontend.def

@@ -119,6 +119,8 @@ ERROR(error_mode_cannot_emit_module,none,
       "this mode does not support emitting modules", ())
 ERROR(error_mode_cannot_emit_module_doc,none,
       "this mode does not support emitting module documentation files", ())
+ERROR(error_mode_cannot_emit_interface,none,
+      "this mode does not support emitting textual interface files", ())
 
 WARNING(emit_reference_dependencies_without_primary_file,none,
   "ignoring -emit-reference-dependencies (requires -primary-file)", ())

include/swift/Basic/SupplementaryOutputPaths.h

@@ -60,6 +60,12 @@ struct SupplementaryOutputPaths {
   /// It is currently only used with WMO, but could be generalized.
   std::string TBDPath;
 
+  /// The path to which we should emit a textual module interface, which can be
+  /// used by a client source file to import this module.
+  ///
+  /// Currently only makes sense when the compiler has whole-module knowledge.
+  std::string ModuleInterfaceOutputPath;
+
   SupplementaryOutputPaths() = default;
   SupplementaryOutputPaths(const SupplementaryOutputPaths &) = default;
 
@@ -68,7 +74,7 @@ struct SupplementaryOutputPaths {
            ModuleDocOutputPath.empty() && DependenciesFilePath.empty() &&
            ReferenceDependenciesFilePath.empty() &&
            SerializedDiagnosticsPath.empty() && LoadedModuleTracePath.empty() &&
-           TBDPath.empty();
+           TBDPath.empty() && ModuleInterfaceOutputPath.empty();
   }
 };
 } // namespace swift

include/swift/Frontend/FrontendInputsAndOutputs.h

@@ -234,6 +234,7 @@ class FrontendInputsAndOutputs {
   bool hasLoadedModuleTracePath() const;
   bool hasModuleOutputPath() const;
   bool hasModuleDocOutputPath() const;
+  bool hasModuleInterfaceOutputPath() const;
   bool hasTBDPath() const;
 
   bool hasDependencyTrackerPath() const;

include/swift/Frontend/FrontendOptions.h

@@ -302,6 +302,7 @@ class FrontendOptions {
   static bool canActionEmitLoadedModuleTrace(ActionType);
   static bool canActionEmitModule(ActionType);
   static bool canActionEmitModuleDoc(ActionType);
+  static bool canActionEmitInterface(ActionType);
 
 public:
   static bool doesActionProduceOutput(ActionType);

include/swift/Frontend/Types.def

@@ -27,45 +27,46 @@
 // The second value is the type id, which will result in a
 // swift::driver::file_types::TY_XX enum constant.
 
-// The third value is the suffix to use when creating temporary files
+// The third value is the extension to use when creating temporary files
 // of this type. It is also used when inferring a type from an extension.
 // If multiple types specify the same extension, the first one is chosen when
 // performing type inference.
 
-// The fifth value is a string containing option flags. For now, this is unused,
-// and should always be the empty string.
+// The fourth value is a string containing option flags. For now, this is
+// unused, and should always be the empty string.
 
 // Input types
-TYPE("swift",           Swift,              "swift",           "")
-TYPE("sil",             SIL,                "sil",             "")
-TYPE("sib",             SIB,                "sib",             "")
+TYPE("swift",               Swift,                     "swift",           "")
+TYPE("sil",                 SIL,                       "sil",             "")
+TYPE("sib",                 SIB,                       "sib",             "")
 
 // Output types
-TYPE("image",           Image,              "out",             "")
-TYPE("object",          Object,             "o",               "")
-TYPE("dSYM",            dSYM,               "dSYM",            "")
-TYPE("dependencies",    Dependencies,       "d",               "")
-TYPE("autolink",        AutolinkFile,       "autolink",        "")
-TYPE("swiftmodule",     SwiftModuleFile,    "swiftmodule",     "")
-TYPE("swiftdoc",        SwiftModuleDocFile, "swiftdoc",        "")
-TYPE("assembly",        Assembly,           "s",               "")
-TYPE("raw-sil",         RawSIL,             "sil",             "")
-TYPE("raw-sib",         RawSIB,             "sib",             "")
-TYPE("llvm-ir",         LLVM_IR,            "ir",              "")
-TYPE("llvm-bc",         LLVM_BC,            "bc",              "")
-TYPE("diagnostics",     SerializedDiagnostics, "dia",          "")
-TYPE("objc-header",     ObjCHeader,         "h",               "")
-TYPE("swift-dependencies", SwiftDeps,       "swiftdeps",       "")
-TYPE("remap",           Remapping,          "remap",           "")
-TYPE("imported-modules", ImportedModules,   "importedmodules", "")
-TYPE("tbd",             TBD,                "tbd",             "")
-TYPE("module-trace",    ModuleTrace,        "trace.json",      "")
-TYPE("index-data",      IndexData,          "",                "")
-TYPE("opt-record",      OptRecord,          "opt.yaml",        "")
+TYPE("image",               Image,                     "out",             "")
+TYPE("object",              Object,                    "o",               "")
+TYPE("dSYM",                dSYM,                      "dSYM",            "")
+TYPE("dependencies",        Dependencies,              "d",               "")
+TYPE("autolink",            AutolinkFile,              "autolink",        "")
+TYPE("swiftmodule",         SwiftModuleFile,           "swiftmodule",     "")
+TYPE("swiftdoc",            SwiftModuleDocFile,        "swiftdoc",        "")
+TYPE("swiftinterface",      SwiftModuleInterfaceFile,  "swiftinterface",  "")
+TYPE("assembly",            Assembly,                  "s",               "")
+TYPE("raw-sil",             RawSIL,                    "sil",             "")
+TYPE("raw-sib",             RawSIB,                    "sib",             "")
+TYPE("llvm-ir",             LLVM_IR,                   "ir",              "")
+TYPE("llvm-bc",             LLVM_BC,                   "bc",              "")
+TYPE("diagnostics",         SerializedDiagnostics,     "dia",             "")
+TYPE("objc-header",         ObjCHeader,                "h",               "")
+TYPE("swift-dependencies",  SwiftDeps,                 "swiftdeps",       "")
+TYPE("remap",               Remapping,                 "remap",           "")
+TYPE("imported-modules",    ImportedModules,           "importedmodules", "")
+TYPE("tbd",                 TBD,                       "tbd",             "")
+TYPE("module-trace",        ModuleTrace,               "trace.json",      "")
+TYPE("index-data",          IndexData,                 "",                "")
+TYPE("opt-record",          OptRecord,                 "opt.yaml",        "")
 
 // Misc types
-TYPE("pcm",             ClangModuleFile,    "pcm",             "")
-TYPE("pch",             PCH,                "pch",             "")
-TYPE("none",            Nothing,            "",                "")
+TYPE("pcm",                 ClangModuleFile,           "pcm",             "")
+TYPE("pch",                 PCH,                       "pch",             "")
+TYPE("none",                Nothing,                   "",                "")
 
 #undef TYPE

include/swift/Option/FrontendOptions.td

@@ -63,6 +63,10 @@ def emit_fixits_path
   : Separate<["-"], "emit-fixits-path">, MetaVarName<"<path>">,
     HelpText<"Output compiler fixits as source edits to <path>">;
 
+def emit_interface_path
+  : Separate<["-"], "emit-interface-path">, MetaVarName<"<path>">,
+    HelpText<"Output textual interface file to <path>">;
+
 def tbd_install_name
   : Separate<["-"], "tbd-install_name">, MetaVarName<"<path>">,
     HelpText<"The install_name to use in an emitted TBD file">;

lib/Driver/Driver.cpp

@@ -1731,6 +1731,7 @@ void Driver::buildActions(SmallVectorImpl<const Action *> &TopLevelActions,
       case file_types::TY_TBD:
       case file_types::TY_ModuleTrace:
       case file_types::TY_OptRecord:
+      case file_types::TY_SwiftModuleInterfaceFile:
         // We could in theory handle assembly or LLVM input, but let's not.
         // FIXME: What about LTO?
         Diags.diagnose(SourceLoc(), diag::error_unexpected_input_file,

lib/Driver/ToolChains.cpp

@@ -432,6 +432,7 @@ const char *ToolChain::JobContext::computeFrontendModeForCompile() const {
   case file_types::TY_ModuleTrace:
   case file_types::TY_TBD:
   case file_types::TY_OptRecord:
+  case file_types::TY_SwiftModuleInterfaceFile:
     llvm_unreachable("Output type can never be primary output.");
   case file_types::TY_INVALID:
     llvm_unreachable("Invalid type ID");
@@ -655,6 +656,7 @@ ToolChain::constructInvocation(const BackendJobAction &job,
     case file_types::TY_Remapping:
     case file_types::TY_ModuleTrace:
     case file_types::TY_OptRecord:
+    case file_types::TY_SwiftModuleInterfaceFile:
       llvm_unreachable("Output type can never be primary output.");
     case file_types::TY_INVALID:
       llvm_unreachable("Invalid type ID");

lib/Frontend/ArgsToFrontendOptionsConverter.cpp

@@ -496,6 +496,11 @@ bool ArgsToFrontendOptionsConverter::checkUnusedSupplementaryOutputPaths()
     Diags.diagnose(SourceLoc(), diag::error_mode_cannot_emit_module_doc);
     return true;
   }
+  if (!FrontendOptions::canActionEmitInterface(Opts.RequestedAction) &&
+      Opts.InputsAndOutputs.hasModuleInterfaceOutputPath()) {
+    Diags.diagnose(SourceLoc(), diag::error_mode_cannot_emit_interface);
+    return true;
+  }
   return false;
 }
 

lib/Frontend/ArgsToFrontendOutputsConverter.cpp

@@ -291,10 +291,13 @@ SupplementaryOutputPathsComputer::getSupplementaryOutputPathsFromArguments()
   auto loadedModuleTrace = getSupplementaryFilenamesFromArguments(
       options::OPT_emit_loaded_module_trace_path);
   auto TBD = getSupplementaryFilenamesFromArguments(options::OPT_emit_tbd_path);
+  auto moduleInterfaceOutput = getSupplementaryFilenamesFromArguments(
+      options::OPT_emit_interface_path);
 
   if (!objCHeaderOutput || !moduleOutput || !moduleDocOutput ||
       !dependenciesFile || !referenceDependenciesFile ||
-      !serializedDiagnostics || !fixItsOutput || !loadedModuleTrace || !TBD) {
+      !serializedDiagnostics || !fixItsOutput || !loadedModuleTrace || !TBD ||
+      !moduleInterfaceOutput) {
     return None;
   }
   std::vector<SupplementaryOutputPaths> result;
@@ -312,6 +315,7 @@ SupplementaryOutputPathsComputer::getSupplementaryOutputPathsFromArguments()
     sop.FixItsOutputPath = (*fixItsOutput)[i];
     sop.LoadedModuleTracePath = (*loadedModuleTrace)[i];
     sop.TBDPath = (*TBD)[i];
+    sop.ModuleInterfaceOutputPath = (*moduleInterfaceOutput)[i];
 
     result.push_back(sop);
   }
@@ -382,6 +386,9 @@ SupplementaryOutputPathsComputer::computeOutputPathsForOneInput(
       SERIALIZED_MODULE_DOC_EXTENSION, "",
       defaultSupplementaryOutputPathExcludingExtension);
 
+  // There is no non-path form of -emit-interface-path
+  auto moduleInterfaceOutputPath = pathsFromArguments.ModuleInterfaceOutputPath;
+
   ID emitModuleOption;
   std::string moduleExtension;
   std::string mainOutputIfUsableForModule;
@@ -403,6 +410,7 @@ SupplementaryOutputPathsComputer::computeOutputPathsForOneInput(
   sop.FixItsOutputPath = fixItsOutputPath;
   sop.LoadedModuleTracePath = loadedModuleTracePath;
   sop.TBDPath = tbdPath;
+  sop.ModuleInterfaceOutputPath = moduleInterfaceOutputPath;
   return sop;
 }
 
@@ -475,7 +483,9 @@ createFromTypeToPathMap(const TypeToPathMap *map) {
       {file_types::TY_SwiftDeps, paths.ReferenceDependenciesFilePath},
       {file_types::TY_SerializedDiagnostics, paths.SerializedDiagnosticsPath},
       {file_types::TY_ModuleTrace, paths.LoadedModuleTracePath},
-      {file_types::TY_TBD, paths.TBDPath}};
+      {file_types::TY_TBD, paths.TBDPath},
+      {file_types::TY_SwiftModuleInterfaceFile,paths.ModuleInterfaceOutputPath}
+  };
   for (const std::pair<file_types::ID, std::string &> &typeAndString :
        typesAndStrings) {
     auto const out = map->find(typeAndString.first);

lib/Frontend/FrontendInputsAndOutputs.cpp

@@ -418,6 +418,12 @@ bool FrontendInputsAndOutputs::hasModuleDocOutputPath() const {
         return outs.ModuleDocOutputPath;
       });
 }
+bool FrontendInputsAndOutputs::hasModuleInterfaceOutputPath() const {
+  return hasSupplementaryOutputPath(
+      [](const SupplementaryOutputPaths &outs) -> const std::string & {
+        return outs.ModuleInterfaceOutputPath;
+      });
+}
 bool FrontendInputsAndOutputs::hasTBDPath() const {
   return hasSupplementaryOutputPath(
       [](const SupplementaryOutputPaths &outs) -> const std::string & {

lib/Frontend/FrontendOptions.cpp

@@ -122,6 +122,7 @@ void FrontendOptions::forAllOutputPaths(
       input.getPrimarySpecificPaths().SupplementaryOutputs;
   const std::string *outputs[] = {&outs.ModuleOutputPath,
                                   &outs.ModuleDocOutputPath,
+                                  &outs.ModuleInterfaceOutputPath,
                                   &outs.ObjCHeaderOutputPath};
   for (const std::string *next : outputs) {
     if (!next->empty())
@@ -348,6 +349,38 @@ bool FrontendOptions::canActionEmitModuleDoc(ActionType action) {
   return canActionEmitModule(action);
 }
 
+bool FrontendOptions::canActionEmitInterface(ActionType action) {
+  switch (action) {
+  case ActionType::NoneAction:
+  case ActionType::Parse:
+  case ActionType::ResolveImports:
+  case ActionType::Typecheck:
+  case ActionType::DumpParse:
+  case ActionType::DumpInterfaceHash:
+  case ActionType::DumpAST:
+  case ActionType::EmitSyntax:
+  case ActionType::PrintAST:
+  case ActionType::EmitPCH:
+  case ActionType::DumpScopeMaps:
+  case ActionType::DumpTypeRefinementContexts:
+  case ActionType::EmitSILGen:
+  case ActionType::EmitSIBGen:
+  case ActionType::Immediate:
+  case ActionType::REPL:
+  case ActionType::EmitImportedModules:
+    return false;
+  case ActionType::MergeModules:
+  case ActionType::EmitModuleOnly:
+  case ActionType::EmitSIL:
+  case ActionType::EmitSIB:
+  case ActionType::EmitIR:
+  case ActionType::EmitBC:
+  case ActionType::EmitAssembly:
+  case ActionType::EmitObject:
+    return true;
+  }
+}
+
 bool FrontendOptions::doesActionProduceOutput(ActionType action) {
   switch (action) {
   case ActionType::Parse:

lib/Frontend/Types.cpp

@@ -75,6 +75,7 @@ bool file_types::isTextual(ID Id) {
   case file_types::TY_TBD:
   case file_types::TY_ModuleTrace:
   case file_types::TY_OptRecord:
+  case file_types::TY_SwiftModuleInterfaceFile:
     return true;
   case file_types::TY_Image:
   case file_types::TY_Object:
@@ -130,6 +131,7 @@ bool file_types::isAfterLLVM(ID Id) {
   case file_types::TY_IndexData:
   case file_types::TY_ModuleTrace:
   case file_types::TY_OptRecord:
+  case file_types::TY_SwiftModuleInterfaceFile:
     return false;
   case file_types::TY_INVALID:
     llvm_unreachable("Invalid type ID.");
@@ -161,6 +163,7 @@ bool file_types::isPartOfSwiftCompilation(ID Id) {
   case file_types::TY_dSYM:
   case file_types::TY_SwiftModuleFile:
   case file_types::TY_SwiftModuleDocFile:
+  case file_types::TY_SwiftModuleInterfaceFile:
   case file_types::TY_SerializedDiagnostics:
   case file_types::TY_ClangModuleFile:
   case file_types::TY_SwiftDeps:

test/Driver/Inputs/invalid-module-name.swift

@@ -1,2 +1,16 @@
-func meow() {
-}
+// Tests what happens when an explicitly-specified or inferred module name isn't
+// a valid Swift identifier.
+
+// RUN: not %target-swift-frontend -emit-silgen -parse-as-library %S/Inputs/invalid-module-name.swift 2>&1 | %FileCheck -check-prefix=INVALID_MODULE_NAME %s
+// INVALID_MODULE_NAME: error: module name "invalid-module-name" is not a valid identifier; use -module-name flag to specify an alternate name
+
+// RUN: not %target-swift-frontend -emit-silgen -parse-as-library %S/Inputs/invalid.module.name.swift 2>&1 | %FileCheck -check-prefix=INVALID_MODULE_NAME2 %s
+// INVALID_MODULE_NAME2: error: module name "invalid.module.name" is not a valid identifier; use -module-name flag to specify an alternate name
+
+// RUN: not %target-swift-frontend -emit-silgen -parse-as-library %S/Inputs/invalid-module-name.swift -module-name still-invalid 2>&1 | %FileCheck -check-prefix=STILL_INVALID %s
+// STILL_INVALID: error: module name "still-invalid" is not a valid identifier{{$}}
+
+// These should succeed.
+// RUN: %target-swift-frontend -emit-silgen %S/Inputs/invalid-module-name.swift > /dev/null
+// RUN: %target-swift-frontend -emit-silgen -parse-as-library %S/Inputs/invalid-module-name.swift -module-name foo > /dev/null
+// RUN: %target-swift-frontend -typecheck -parse-as-library %S/Inputs/invalid-module-name.swift -module-name foo

test/Driver/Inputs/lib.swift

@@ -1,3 +1,3 @@
-// Used by multiple_input.swift and emit-objc-header.swift tests.
+// Used by emit-objc-header.swift and others.
 
 func libraryFunction() {}

test/Driver/Inputs/main.swift

@@ -1,5 +1,5 @@
-// Used by multiple_input.swift and emit-objc-header.swift tests. This file
-// should be inferred as the main source file from its name.
+// Used by emit-objc-header.swift and others.
+// This file should be inferred as the main source file from its name.
 
 var x = 4 + 5
 print(x)