[Bridging PCH] Add -emit-pch to Frontend; call emitBridgingPCH.

Author: graydon

include/swift/AST/DiagnosticsClangImporter.def

@@ -53,6 +53,9 @@ ERROR(bridging_header_error,Fatal,
 WARNING(could_not_rewrite_bridging_header,none,
   "failed to serialize bridging header; "
   "target may not be debuggable outside of its original project", ())
+ERROR(bridging_header_pch_error,Fatal,
+   "failed to emit PCH file '%0' for bridging header '%1'",
+   (StringRef, StringRef))
 
 WARNING(invalid_swift_name_method,none,
   "too %select{few|many}0 parameters in swift_name attribute (expected %1; "

include/swift/Driver/Types.def

@@ -60,6 +60,7 @@ TYPE("remap",           Remapping,          "remap",           "")
 
 // Misc types
 TYPE("pcm",             ClangModuleFile,    "pcm",             "")
+TYPE("pch",             PCH,                "pch",             "")
 TYPE("none",            Nothing,            "",                "")
 
 #undef TYPE

include/swift/Frontend/FrontendOptions.h

@@ -149,6 +149,8 @@ class FrontendOptions {
     /// Parse, type-check, and dump type refinement context hierarchy
     DumpTypeRefinementContexts,
 
+    EmitPCH, ///< Emit PCH of imported bridging header
+
     EmitSILGen, ///< Emit raw SIL
     EmitSIL, ///< Emit canonical SIL
 

include/swift/Option/FrontendOptions.td

@@ -233,6 +233,9 @@ def disable_modules_validate_system_headers : Flag<["-"], "disable-modules-valid
 def emit_verbose_sil : Flag<["-"], "emit-verbose-sil">,
   HelpText<"Emit locations during SIL emission">;
 
+def emit_pch : Flag<["-"], "emit-pch">,
+  HelpText<"Emit PCH for imported Objective-C header file">, ModeOpt;
+
 def enable_sil_ownership : Flag<["-"], "enable-sil-ownership">,
   HelpText<"Enable the SIL Ownership Model">;
 

include/swift/Strings.h

@@ -18,6 +18,8 @@ namespace swift {
   static const char SERIALIZED_MODULE_EXTENSION[] = "swiftmodule";
   /// The extension for serialized documentation comments.
   static const char SERIALIZED_MODULE_DOC_EXTENSION[] = "swiftdoc";
+  /// The extension for PCH files.
+  static const char PCH_EXTENSION[] = "pch";
   /// The extension for SIL files.
   static const char SIL_EXTENSION[] = "sil";
   /// The extension for SIB files.

lib/Driver/Driver.cpp

@@ -1073,6 +1073,11 @@ void Driver::buildOutputInfo(const ToolChain &TC, const DerivedArgList &Args,
       OI.CompilerOutputType = types::TY_LLVM_BC;
       break;
 
+    case options::OPT_emit_pch:
+      OI.CompilerMode = OutputInfo::Mode::SingleCompile;
+      OI.CompilerOutputType = types::TY_PCH;
+      break;
+
     case options::OPT_parse:
     case options::OPT_typecheck:
     case options::OPT_dump_parse:
@@ -1328,6 +1333,7 @@ void Driver::buildActions(const ToolChain &TC,
       case types::TY_ClangModuleFile:
       case types::TY_SwiftDeps:
       case types::TY_Remapping:
+      case types::TY_PCH:
         // 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

@@ -191,6 +191,9 @@ ToolChain::constructInvocation(const CompileJobAction &job,
     case types::TY_Object:
       FrontendModeOption = "-c";
       break;
+    case types::TY_PCH:
+      FrontendModeOption = "-emit-pch";
+      break;
     case types::TY_RawSIL:
       FrontendModeOption = "-emit-silgen";
       break;
@@ -480,6 +483,7 @@ ToolChain::constructInvocation(const BackendJobAction &job,
     case types::TY_RawSIB:
     case types::TY_SIL:
     case types::TY_SIB:
+    case types::TY_PCH:
       llvm_unreachable("Cannot be output from backend job");
     case types::TY_Swift:
     case types::TY_dSYM:

lib/Driver/Types.cpp

@@ -78,6 +78,7 @@ bool types::isTextual(ID Id) {
   case types::TY_Image:
   case types::TY_Object:
   case types::TY_dSYM:
+  case types::TY_PCH:
   case types::TY_SIB:
   case types::TY_RawSIB:
   case types::TY_SwiftModuleFile:
@@ -105,6 +106,7 @@ bool types::isAfterLLVM(ID Id) {
   case types::TY_Object:
     return true;
   case types::TY_Swift:
+  case types::TY_PCH:
   case types::TY_SIL:
   case types::TY_Dependencies:
   case types::TY_RawSIL:
@@ -145,6 +147,7 @@ bool types::isPartOfSwiftCompilation(ID Id) {
   case types::TY_Dependencies:
   case types::TY_ObjCHeader:
   case types::TY_AutolinkFile:
+  case types::TY_PCH:
   case types::TY_Image:
   case types::TY_dSYM:
   case types::TY_SwiftModuleFile:

lib/Frontend/CompilerInvocation.cpp

@@ -256,6 +256,8 @@ static bool ParseFrontendArgs(FrontendOptions &Opts, ArgList &Args,
       Action = FrontendOptions::EmitSIB;
     } else if (Opt.matches(OPT_emit_sibgen)) {
       Action = FrontendOptions::EmitSIBGen;
+    } else if (Opt.matches(OPT_emit_pch)) {
+      Action = FrontendOptions::EmitPCH;
     } else if (Opt.matches(OPT_parse)) {
       Action = FrontendOptions::Parse;
     } else if (Opt.matches(OPT_typecheck)) {
@@ -482,6 +484,10 @@ static bool ParseFrontendArgs(FrontendOptions &Opts, ArgList &Args,
       Opts.setSingleOutputFilename("-");
       break;
 
+    case FrontendOptions::EmitPCH:
+      Suffix = PCH_EXTENSION;
+      break;
+
     case FrontendOptions::EmitSILGen:
     case FrontendOptions::EmitSIL: {
       if (Opts.OutputFilenames.empty())
@@ -675,6 +681,7 @@ static bool ParseFrontendArgs(FrontendOptions &Opts, ArgList &Args,
     case FrontendOptions::Parse:
     case FrontendOptions::Typecheck:
     case FrontendOptions::EmitModuleOnly:
+    case FrontendOptions::EmitPCH:
     case FrontendOptions::EmitSILGen:
     case FrontendOptions::EmitSIL:
     case FrontendOptions::EmitSIBGen:
@@ -694,6 +701,7 @@ static bool ParseFrontendArgs(FrontendOptions &Opts, ArgList &Args,
     case FrontendOptions::DumpInterfaceHash:
     case FrontendOptions::DumpAST:
     case FrontendOptions::PrintAST:
+    case FrontendOptions::EmitPCH:
     case FrontendOptions::DumpScopeMaps:
     case FrontendOptions::DumpTypeRefinementContexts:
     case FrontendOptions::Immediate:
@@ -725,6 +733,7 @@ static bool ParseFrontendArgs(FrontendOptions &Opts, ArgList &Args,
     case FrontendOptions::DumpInterfaceHash:
     case FrontendOptions::DumpAST:
     case FrontendOptions::PrintAST:
+    case FrontendOptions::EmitPCH:
     case FrontendOptions::DumpScopeMaps:
     case FrontendOptions::DumpTypeRefinementContexts:
     case FrontendOptions::EmitSILGen:

lib/Frontend/FrontendOptions.cpp

@@ -28,6 +28,7 @@ bool FrontendOptions::actionHasOutput() const {
   case DumpScopeMaps:
   case DumpTypeRefinementContexts:
     return false;
+  case EmitPCH:
   case EmitSILGen:
   case EmitSIL:
   case EmitSIBGen:
@@ -57,6 +58,7 @@ bool FrontendOptions::actionIsImmediate() const {
   case PrintAST:
   case DumpScopeMaps:
   case DumpTypeRefinementContexts:
+  case EmitPCH:
   case EmitSILGen:
   case EmitSIL:
   case EmitSIBGen:

lib/FrontendTool/FrontendTool.cpp

@@ -335,6 +335,15 @@ static bool performCompile(std::unique_ptr<CompilerInstance> &Instance,
   FrontendOptions opts = Invocation.getFrontendOptions();
   FrontendOptions::ActionType Action = opts.RequestedAction;
 
+  // We've been asked to precompile a bridging header; we want to
+  // avoid touching any other inputs and just parse, emit and exit.
+  if (Action == FrontendOptions::EmitPCH) {
+    auto clangImporter = static_cast<ClangImporter *>(
+      Instance->getASTContext().getClangModuleLoader());
+    return clangImporter->emitBridgingPCH(
+      Invocation.getInputFilenames()[0], opts.getSingleOutputFilename());
+  }
+
   IRGenOptions &IRGenOpts = Invocation.getIRGenOptions();
 
   bool inputIsLLVMIr = Invocation.getInputKind() == InputFileKind::IFK_LLVM_IR;