From 512cf211489bd55da3e81206c4bdcc048f3af877 Mon Sep 17 00:00:00 2001
From: Allan Shortlidge <shortlidge@apple.com>
Date: Mon, 11 Aug 2025 19:09:10 -0700
Subject: [PATCH 1/3] Frontend: Make -dump-availability-scopes an option
 instead of a mode.

Allowing it to be specified in conjunction with any frontend mode makes it a
more flexible debugging tool.
---
 include/swift/Frontend/FrontendOptions.h      |  7 ++++---
 include/swift/Option/FrontendOptions.td       |  3 +++
 include/swift/Option/Options.td               |  6 +-----
 .../ArgsToFrontendOptionsConverter.cpp        |  3 +--
 .../ArgsToFrontendOutputsConverter.cpp        |  1 -
 lib/Frontend/FrontendOptions.cpp              | 21 -------------------
 lib/FrontendTool/FrontendTool.cpp             | 17 +++++++--------
 7 files changed, 17 insertions(+), 41 deletions(-)

diff --git a/include/swift/Frontend/FrontendOptions.h b/include/swift/Frontend/FrontendOptions.h
index 01d889fb97379..a68d6fa409e1f 100644
--- a/include/swift/Frontend/FrontendOptions.h
+++ b/include/swift/Frontend/FrontendOptions.h
@@ -167,9 +167,6 @@ class FrontendOptions {
     /// Parse and dump scope map.
     DumpScopeMaps,
 
-    /// Parse, type-check, and dump availability scopes
-    DumpAvailabilityScopes,
-
     EmitImportedModules, ///< Emit the modules that this one imports
     EmitPCH,             ///< Emit PCH of imported bridging header
 
@@ -313,6 +310,10 @@ class FrontendOptions {
   /// upon termination.
   bool DumpClangLookupTables = false;
 
+  /// Indicates whether or not availability scopes should be dumped upon
+  /// termination.
+  bool DumpAvailabilityScopes = false;
+
   /// Indicates whether standard help should be shown.
   bool PrintHelp = false;
 
diff --git a/include/swift/Option/FrontendOptions.td b/include/swift/Option/FrontendOptions.td
index a032b6caeccf4..77322cbb18ef2 100644
--- a/include/swift/Option/FrontendOptions.td
+++ b/include/swift/Option/FrontendOptions.td
@@ -673,6 +673,9 @@ def dump_clang_lookup_tables : Flag<["-"], "dump-clang-lookup-tables">,
   HelpText<"Dump the importer's Swift-name-to-Clang-name lookup tables to "
            "stderr">;
 
+def dump_availability_scopes : Flag<["-"], "dump-availability-scopes">,
+                               HelpText<"Dump availability scopes to stderr">;
+
 def disable_modules_validate_system_headers : Flag<["-"], "disable-modules-validate-system-headers">,
   HelpText<"Disable validating system headers in the Clang importer">;
 
diff --git a/include/swift/Option/Options.td b/include/swift/Option/Options.td
index 3c9e8f1630115..e95b32310dcc9 100644
--- a/include/swift/Option/Options.td
+++ b/include/swift/Option/Options.td
@@ -1435,11 +1435,7 @@ def dump_scope_maps : Separate<["-"], "dump-scope-maps">,
   MetaVarName<"<expanded-or-list-of-line:column>">,
   ModeOpt,
   Flags<[FrontendOption, NoInteractiveOption, DoesNotAffectIncrementalBuild]>;
-def dump_availability_scopes :
-  Flag<["-"], "dump-availability-scopes">,
-  HelpText<"Type-check input file(s) and dump availability scopes">,
-  ModeOpt,
-  Flags<[FrontendOption, NoInteractiveOption, DoesNotAffectIncrementalBuild]>;
+
 def dump_type_info : Flag<["-"], "dump-type-info">,
   HelpText<"Output YAML dump of fixed-size types from all imported modules">,
   ModeOpt,
diff --git a/lib/Frontend/ArgsToFrontendOptionsConverter.cpp b/lib/Frontend/ArgsToFrontendOptionsConverter.cpp
index e2ffe6511d64a..1fa65c581101b 100644
--- a/lib/Frontend/ArgsToFrontendOptionsConverter.cpp
+++ b/lib/Frontend/ArgsToFrontendOptionsConverter.cpp
@@ -198,6 +198,7 @@ bool ArgsToFrontendOptionsConverter::convert(
   computeTBDOptions();
 
   Opts.DumpClangLookupTables |= Args.hasArg(OPT_dump_clang_lookup_tables);
+  Opts.DumpAvailabilityScopes |= Args.hasArg(OPT_dump_availability_scopes);
 
   Opts.CheckOnoneSupportCompleteness = Args.hasArg(OPT_check_onone_completeness);
 
@@ -665,8 +666,6 @@ ArgsToFrontendOptionsConverter::determineRequestedAction(const ArgList &args) {
     return FrontendOptions::ActionType::MergeModules;
   if (Opt.matches(OPT_dump_scope_maps))
     return FrontendOptions::ActionType::DumpScopeMaps;
-  if (Opt.matches(OPT_dump_availability_scopes))
-    return FrontendOptions::ActionType::DumpAvailabilityScopes;
   if (Opt.matches(OPT_dump_interface_hash))
     return FrontendOptions::ActionType::DumpInterfaceHash;
   if (Opt.matches(OPT_dump_type_info))
diff --git a/lib/Frontend/ArgsToFrontendOutputsConverter.cpp b/lib/Frontend/ArgsToFrontendOutputsConverter.cpp
index 4a726c8fbd570..31cfd92649ebb 100644
--- a/lib/Frontend/ArgsToFrontendOutputsConverter.cpp
+++ b/lib/Frontend/ArgsToFrontendOutputsConverter.cpp
@@ -473,7 +473,6 @@ static bool shouldEmitFineModuleTrace(FrontendOptions::ActionType action) {
   case swift::FrontendOptions::ActionType::PrintAST:
   case swift::FrontendOptions::ActionType::PrintASTDecl:
   case swift::FrontendOptions::ActionType::DumpScopeMaps:
-  case swift::FrontendOptions::ActionType::DumpAvailabilityScopes:
   case swift::FrontendOptions::ActionType::EmitImportedModules:
   case swift::FrontendOptions::ActionType::EmitPCH:
   case swift::FrontendOptions::ActionType::EmitModuleOnly:
diff --git a/lib/Frontend/FrontendOptions.cpp b/lib/Frontend/FrontendOptions.cpp
index bad0f40c23050..3cf4b1ece3fee 100644
--- a/lib/Frontend/FrontendOptions.cpp
+++ b/lib/Frontend/FrontendOptions.cpp
@@ -41,7 +41,6 @@ bool FrontendOptions::needsProperModuleName(ActionType action) {
   case ActionType::PrintAST:
   case ActionType::PrintASTDecl:
   case ActionType::DumpScopeMaps:
-  case ActionType::DumpAvailabilityScopes:
   case ActionType::DumpPCM:
   case ActionType::EmitPCH:
     return false;
@@ -111,7 +110,6 @@ bool FrontendOptions::doesActionRequireSwiftStandardLibrary(ActionType action) {
   case ActionType::PrintAST:
   case ActionType::PrintASTDecl:
   case ActionType::DumpScopeMaps:
-  case ActionType::DumpAvailabilityScopes:
   case ActionType::EmitSILGen:
   case ActionType::EmitSIL:
   case ActionType::EmitLoweredSIL:
@@ -157,7 +155,6 @@ bool FrontendOptions::doesActionRequireInputs(ActionType action) {
   case ActionType::PrintAST:
   case ActionType::PrintASTDecl:
   case ActionType::DumpScopeMaps:
-  case ActionType::DumpAvailabilityScopes:
   case ActionType::EmitSILGen:
   case ActionType::EmitSIL:
   case ActionType::EmitLoweredSIL:
@@ -200,7 +197,6 @@ bool FrontendOptions::doesActionPerformEndOfPipelineActions(ActionType action) {
   case ActionType::PrintAST:
   case ActionType::PrintASTDecl:
   case ActionType::DumpScopeMaps:
-  case ActionType::DumpAvailabilityScopes:
   case ActionType::EmitSILGen:
   case ActionType::EmitSIL:
   case ActionType::EmitLoweredSIL:
@@ -239,7 +235,6 @@ bool FrontendOptions::supportCompilationCaching(ActionType action) {
   case ActionType::PrintAST:
   case ActionType::PrintASTDecl:
   case ActionType::DumpScopeMaps:
-  case ActionType::DumpAvailabilityScopes:
   case ActionType::MergeModules:
   case ActionType::Immediate:
   case ActionType::DumpTypeInfo:
@@ -305,7 +300,6 @@ FrontendOptions::formatForPrincipalOutputFileForAction(ActionType action) {
   case ActionType::PrintAST:
   case ActionType::PrintASTDecl:
   case ActionType::DumpScopeMaps:
-  case ActionType::DumpAvailabilityScopes:
   case ActionType::DumpTypeInfo:
   case ActionType::DumpPCM:
   case ActionType::PrintVersion:
@@ -378,7 +372,6 @@ bool FrontendOptions::canActionEmitDependencies(ActionType action) {
   case ActionType::PrintAST:
   case ActionType::PrintASTDecl:
   case ActionType::DumpScopeMaps:
-  case ActionType::DumpAvailabilityScopes:
   case ActionType::DumpTypeInfo:
   case ActionType::CompileModuleFromInterface:
   case ActionType::TypecheckModuleFromInterface:
@@ -422,7 +415,6 @@ bool FrontendOptions::canActionEmitReferenceDependencies(ActionType action) {
   case ActionType::PrintAST:
   case ActionType::PrintASTDecl:
   case ActionType::DumpScopeMaps:
-  case ActionType::DumpAvailabilityScopes:
   case ActionType::DumpTypeInfo:
   case ActionType::CompileModuleFromInterface:
   case ActionType::TypecheckModuleFromInterface:
@@ -467,7 +459,6 @@ bool FrontendOptions::canActionEmitModuleSummary(ActionType action) {
   case ActionType::EmitImportedModules:
   case ActionType::EmitPCH:
   case ActionType::DumpScopeMaps:
-  case ActionType::DumpAvailabilityScopes:
   case ActionType::DumpTypeInfo:
   case ActionType::EmitSILGen:
   case ActionType::EmitSIBGen:
@@ -509,7 +500,6 @@ bool FrontendOptions::canActionEmitClangHeader(ActionType action) {
   case ActionType::PrintASTDecl:
   case ActionType::EmitPCH:
   case ActionType::DumpScopeMaps:
-  case ActionType::DumpAvailabilityScopes:
   case ActionType::DumpTypeInfo:
   case ActionType::CompileModuleFromInterface:
   case ActionType::TypecheckModuleFromInterface:
@@ -550,7 +540,6 @@ bool FrontendOptions::canActionEmitLoadedModuleTrace(ActionType action) {
   case ActionType::PrintAST:
   case ActionType::PrintASTDecl:
   case ActionType::DumpScopeMaps:
-  case ActionType::DumpAvailabilityScopes:
   case ActionType::DumpTypeInfo:
   case ActionType::CompileModuleFromInterface:
   case ActionType::TypecheckModuleFromInterface:
@@ -600,7 +589,6 @@ bool FrontendOptions::canActionEmitModuleSemanticInfo(ActionType action) {
   case ActionType::PrintASTDecl:
   case ActionType::EmitPCH:
   case ActionType::DumpScopeMaps:
-  case ActionType::DumpAvailabilityScopes:
   case ActionType::DumpTypeInfo:
   case ActionType::EmitSILGen:
   case ActionType::TypecheckModuleFromInterface:
@@ -643,7 +631,6 @@ bool FrontendOptions::canActionEmitConstValues(ActionType action) {
   case ActionType::PrintAST:
   case ActionType::PrintASTDecl:
   case ActionType::DumpScopeMaps:
-  case ActionType::DumpAvailabilityScopes:
   case ActionType::DumpTypeInfo:
   case ActionType::CompileModuleFromInterface:
   case ActionType::TypecheckModuleFromInterface:
@@ -687,7 +674,6 @@ bool FrontendOptions::canActionEmitModule(ActionType action) {
   case ActionType::PrintASTDecl:
   case ActionType::EmitPCH:
   case ActionType::DumpScopeMaps:
-  case ActionType::DumpAvailabilityScopes:
   case ActionType::DumpTypeInfo:
   case ActionType::EmitSILGen:
   case ActionType::CompileModuleFromInterface:
@@ -733,7 +719,6 @@ bool FrontendOptions::canActionEmitInterface(ActionType action) {
   case ActionType::EmitImportedModules:
   case ActionType::EmitPCH:
   case ActionType::DumpScopeMaps:
-  case ActionType::DumpAvailabilityScopes:
   case ActionType::DumpTypeInfo:
   case ActionType::EmitSILGen:
   case ActionType::EmitSIBGen:
@@ -776,7 +761,6 @@ bool FrontendOptions::canActionEmitAPIDescriptor(ActionType action) {
   case ActionType::EmitImportedModules:
   case ActionType::EmitPCH:
   case ActionType::DumpScopeMaps:
-  case ActionType::DumpAvailabilityScopes:
   case ActionType::DumpTypeInfo:
   case ActionType::EmitSILGen:
   case ActionType::EmitSIBGen:
@@ -818,7 +802,6 @@ bool FrontendOptions::doesActionProduceOutput(ActionType action) {
   case ActionType::PrintAST:
   case ActionType::PrintASTDecl:
   case ActionType::DumpScopeMaps:
-  case ActionType::DumpAvailabilityScopes:
   case ActionType::EmitPCH:
   case ActionType::EmitSILGen:
   case ActionType::EmitSIL:
@@ -877,7 +860,6 @@ bool FrontendOptions::doesActionProduceTextualOutput(ActionType action) {
   case ActionType::PrintAST:
   case ActionType::PrintASTDecl:
   case ActionType::DumpScopeMaps:
-  case ActionType::DumpAvailabilityScopes:
   case ActionType::EmitImportedModules:
   case ActionType::EmitSILGen:
   case ActionType::EmitSIL:
@@ -907,7 +889,6 @@ bool FrontendOptions::doesActionGenerateSIL(ActionType action) {
   case ActionType::PrintAST:
   case ActionType::PrintASTDecl:
   case ActionType::DumpScopeMaps:
-  case ActionType::DumpAvailabilityScopes:
   case ActionType::EmitImportedModules:
   case ActionType::EmitPCH:
   case ActionType::CompileModuleFromInterface:
@@ -948,7 +929,6 @@ bool FrontendOptions::doesActionGenerateIR(ActionType action) {
   case ActionType::PrintAST:
   case ActionType::PrintASTDecl:
   case ActionType::DumpScopeMaps:
-  case ActionType::DumpAvailabilityScopes:
   case ActionType::DumpTypeInfo:
   case ActionType::CompileModuleFromInterface:
   case ActionType::TypecheckModuleFromInterface:
@@ -994,7 +974,6 @@ bool FrontendOptions::doesActionBuildModuleFromInterface(ActionType action) {
   case ActionType::PrintAST:
   case ActionType::PrintASTDecl:
   case ActionType::DumpScopeMaps:
-  case ActionType::DumpAvailabilityScopes:
   case ActionType::DumpTypeInfo:
   case ActionType::Typecheck:
   case ActionType::ResolveImports:
diff --git a/lib/FrontendTool/FrontendTool.cpp b/lib/FrontendTool/FrontendTool.cpp
index 2d9798e7da123..3aff1718e5eb7 100644
--- a/lib/FrontendTool/FrontendTool.cpp
+++ b/lib/FrontendTool/FrontendTool.cpp
@@ -1040,6 +1040,10 @@ static void performEndOfPipelineActions(CompilerInstance &Instance) {
   if (opts.DumpClangLookupTables && ctx.getClangModuleLoader())
     ctx.getClangModuleLoader()->dumpSwiftLookupTables();
 
+  if (opts.DumpAvailabilityScopes)
+    getPrimaryOrMainSourceFile(Instance).getAvailabilityScope()->dump(
+        llvm::errs(), Instance.getASTContext().SourceMgr);
+
   // Report mangling stats if there was no error.
   if (!ctx.hadError())
     Mangle::printManglingStats();
@@ -1295,17 +1299,12 @@ static bool performAction(CompilerInstance &Instance,
         });
   case FrontendOptions::ActionType::DumpScopeMaps:
     return withSemanticAnalysis(
-        Instance, observer, [](CompilerInstance &Instance) {
+        Instance, observer,
+        [](CompilerInstance &Instance) {
           return dumpAndPrintScopeMap(Instance,
                                       getPrimaryOrMainSourceFile(Instance));
-        }, /*runDespiteErrors=*/true);
-  case FrontendOptions::ActionType::DumpAvailabilityScopes:
-    return withSemanticAnalysis(
-        Instance, observer, [](CompilerInstance &Instance) {
-          getPrimaryOrMainSourceFile(Instance).getAvailabilityScope()->dump(
-              llvm::errs(), Instance.getASTContext().SourceMgr);
-          return Instance.getASTContext().hadError();
-        }, /*runDespiteErrors=*/true);
+        },
+        /*runDespiteErrors=*/true);
   case FrontendOptions::ActionType::DumpInterfaceHash:
     getPrimaryOrMainSourceFile(Instance).dumpInterfaceHash(llvm::errs());
     return Instance.getASTContext().hadError();

From 901e8becb2158a57ab25bb157439301c6aeed397 Mon Sep 17 00:00:00 2001
From: Allan Shortlidge <shortlidge@apple.com>
Date: Tue, 12 Aug 2025 09:32:24 -0700
Subject: [PATCH 2/3] Frontend: Make getPrimaryOrMainSourceFile() a utility on
 CompilerInstance.

---
 include/swift/Frontend/Frontend.h |  6 ++++++
 lib/FrontendTool/FrontendTool.cpp | 20 ++++++--------------
 2 files changed, 12 insertions(+), 14 deletions(-)

diff --git a/include/swift/Frontend/Frontend.h b/include/swift/Frontend/Frontend.h
index 029e296ab5d38..caeaf4d440301 100644
--- a/include/swift/Frontend/Frontend.h
+++ b/include/swift/Frontend/Frontend.h
@@ -710,6 +710,12 @@ class CompilerInstance {
     }
   }
 
+  SourceFile &getPrimaryOrMainSourceFile() const {
+    if (SourceFile *SF = getPrimarySourceFile())
+      return *SF;
+    return getMainModule()->getMainSourceFile();
+  }
+
   /// Returns true if there was an error during setup.
   bool setup(const CompilerInvocation &Invocation, std::string &Error,
              ArrayRef<const char *> Args = {});
diff --git a/lib/FrontendTool/FrontendTool.cpp b/lib/FrontendTool/FrontendTool.cpp
index 3aff1718e5eb7..afa4b40087ae0 100644
--- a/lib/FrontendTool/FrontendTool.cpp
+++ b/lib/FrontendTool/FrontendTool.cpp
@@ -458,14 +458,6 @@ static bool dumpAndPrintScopeMap(const CompilerInstance &Instance,
   return Instance.getASTContext().hadError();
 }
 
-static SourceFile &
-getPrimaryOrMainSourceFile(const CompilerInstance &Instance) {
-  if (SourceFile *SF = Instance.getPrimarySourceFile()) {
-    return *SF;
-  }
-  return Instance.getMainModule()->getMainSourceFile();
-}
-
 /// Dumps the AST of all available primary source files. If corresponding output
 /// files were specified, use them; otherwise, dump the AST to stdout.
 static bool dumpAST(CompilerInstance &Instance,
@@ -512,7 +504,7 @@ static bool dumpAST(CompilerInstance &Instance,
   } else {
     // Some invocations don't have primary files. In that case, we default to
     // looking for the main file and dumping it to `stdout`.
-    auto &SF = getPrimaryOrMainSourceFile(Instance);
+    auto &SF = Instance.getPrimaryOrMainSourceFile();
     dumpAST(&SF, llvm::outs());
   }
   return Instance.getASTContext().hadError();
@@ -1041,7 +1033,7 @@ static void performEndOfPipelineActions(CompilerInstance &Instance) {
     ctx.getClangModuleLoader()->dumpSwiftLookupTables();
 
   if (opts.DumpAvailabilityScopes)
-    getPrimaryOrMainSourceFile(Instance).getAvailabilityScope()->dump(
+    Instance.getPrimaryOrMainSourceFile().getAvailabilityScope()->dump(
         llvm::errs(), Instance.getASTContext().SourceMgr);
 
   // Report mangling stats if there was no error.
@@ -1286,14 +1278,14 @@ static bool performAction(CompilerInstance &Instance,
   case FrontendOptions::ActionType::PrintAST:
     return withSemanticAnalysis(
         Instance, observer, [](CompilerInstance &Instance) {
-          getPrimaryOrMainSourceFile(Instance).print(
+          Instance.getPrimaryOrMainSourceFile().print(
               llvm::outs(), PrintOptions::printEverything());
           return Instance.getASTContext().hadError();
         });
   case FrontendOptions::ActionType::PrintASTDecl:
     return withSemanticAnalysis(
         Instance, observer, [](CompilerInstance &Instance) {
-          getPrimaryOrMainSourceFile(Instance).print(
+          Instance.getPrimaryOrMainSourceFile().print(
               llvm::outs(), PrintOptions::printDeclarations());
           return Instance.getASTContext().hadError();
         });
@@ -1302,11 +1294,11 @@ static bool performAction(CompilerInstance &Instance,
         Instance, observer,
         [](CompilerInstance &Instance) {
           return dumpAndPrintScopeMap(Instance,
-                                      getPrimaryOrMainSourceFile(Instance));
+                                      Instance.getPrimaryOrMainSourceFile());
         },
         /*runDespiteErrors=*/true);
   case FrontendOptions::ActionType::DumpInterfaceHash:
-    getPrimaryOrMainSourceFile(Instance).dumpInterfaceHash(llvm::errs());
+    Instance.getPrimaryOrMainSourceFile().dumpInterfaceHash(llvm::errs());
     return Instance.getASTContext().hadError();
   case FrontendOptions::ActionType::EmitImportedModules:
     return emitImportedModules(Instance.getMainModule(), opts,

From 5d3d93478a08c9f420788a74f57dc816b20919e1 Mon Sep 17 00:00:00 2001
From: Allan Shortlidge <shortlidge@apple.com>
Date: Tue, 12 Aug 2025 09:36:37 -0700
Subject: [PATCH 3/3] Frontend: Inherit compiler debugging options during
 module interface actions.

When building a module interface for the -typecheck-module-from-interface or
-compile-module-from-interface actions, inherit and honor compiler debugging
options and emit debugging output at the end of the interface build.
---
 include/swift/Frontend/Frontend.h             |  3 ++
 include/swift/Frontend/FrontendOptions.h      | 30 +++++++++++--------
 .../swift/Frontend/ModuleInterfaceLoader.h    | 28 ++++-------------
 .../ArgsToFrontendOptionsConverter.cpp        | 10 +++++--
 lib/Frontend/Frontend.cpp                     | 18 +++++++++++
 lib/Frontend/ModuleInterfaceBuilder.cpp       |  4 +++
 lib/Frontend/ModuleInterfaceLoader.cpp        | 29 ++++++++++++++++++
 lib/FrontendTool/FrontendTool.cpp             | 16 +++-------
 .../ModuleInterface/availability-scopes.swift | 10 +++++++
 9 files changed, 99 insertions(+), 49 deletions(-)
 create mode 100644 test/ModuleInterface/availability-scopes.swift

diff --git a/include/swift/Frontend/Frontend.h b/include/swift/Frontend/Frontend.h
index caeaf4d440301..7988413f57bfc 100644
--- a/include/swift/Frontend/Frontend.h
+++ b/include/swift/Frontend/Frontend.h
@@ -798,6 +798,9 @@ class CompilerInstance {
   /// \returns true if any errors occurred.
   bool performSILProcessing(SILModule *silModule);
 
+  /// Dumps any debugging output for the compilation, if requested.
+  void emitEndOfPipelineDebuggingOutput();
+
 private:
   /// Creates a new source file for the main module.
   SourceFile *createSourceFileForMainModule(ModuleDecl *mod,
diff --git a/include/swift/Frontend/FrontendOptions.h b/include/swift/Frontend/FrontendOptions.h
index a68d6fa409e1f..a120e58903263 100644
--- a/include/swift/Frontend/FrontendOptions.h
+++ b/include/swift/Frontend/FrontendOptions.h
@@ -35,6 +35,21 @@ namespace llvm {
 namespace swift {
 enum class IntermoduleDepTrackingMode;
 
+/// Options for debugging the behavior of the frontend.
+struct CompilerDebuggingOptions {
+  /// Indicates whether or not the Clang importer should print statistics upon
+  /// termination.
+  bool PrintClangStats = false;
+
+  /// Indicates whether or not the availability scope trees built during
+  /// compilation should be dumped upon termination.
+  bool DumpAvailabilityScopes = false;
+
+  /// Indicates whether or not the Clang importer should dump lookup tables
+  /// upon termination.
+  bool DumpClangLookupTables = false;
+};
+
 /// Options for controlling the behavior of the frontend.
 class FrontendOptions {
   friend class ArgsToFrontendOptionsConverter;
@@ -124,6 +139,9 @@ class FrontendOptions {
   /// A set of modules allowed to import this module.
   std::set<std::string> AllowableClients;
 
+  /// Options for debugging the compiler.
+  CompilerDebuggingOptions CompilerDebuggingOpts;
+
   /// Emit index data for imported serialized swift system modules.
   bool IndexSystemModules = false;
 
@@ -302,18 +320,6 @@ class FrontendOptions {
   /// termination.
   bool PrintStats = false;
 
-  /// Indicates whether or not the Clang importer should print statistics upon
-  /// termination.
-  bool PrintClangStats = false;
-
-  /// Indicates whether or not the Clang importer should dump lookup tables
-  /// upon termination.
-  bool DumpClangLookupTables = false;
-
-  /// Indicates whether or not availability scopes should be dumped upon
-  /// termination.
-  bool DumpAvailabilityScopes = false;
-
   /// Indicates whether standard help should be shown.
   bool PrintHelp = false;
 
diff --git a/include/swift/Frontend/ModuleInterfaceLoader.h b/include/swift/Frontend/ModuleInterfaceLoader.h
index 2aa2124b70441..a4148599e08cc 100644
--- a/include/swift/Frontend/ModuleInterfaceLoader.h
+++ b/include/swift/Frontend/ModuleInterfaceLoader.h
@@ -455,7 +455,8 @@ class ExplicitModuleMapParser {
   llvm::StringSaver Saver;
 };
 
-struct ModuleInterfaceLoaderOptions {
+class ModuleInterfaceLoaderOptions {
+public:
   FrontendOptions::ActionType requestedAction =
       FrontendOptions::ActionType::EmitModuleOnly;
   bool remarkOnRebuildFromInterface = false;
@@ -464,28 +465,11 @@ struct ModuleInterfaceLoaderOptions {
   bool disableBuildingInterface = false;
   bool downgradeInterfaceVerificationError = false;
   bool strictImplicitModuleContext = false;
+  CompilerDebuggingOptions compilerDebuggingOptions;
   std::string mainExecutablePath;
-  ModuleInterfaceLoaderOptions(const FrontendOptions &Opts):
-    remarkOnRebuildFromInterface(Opts.RemarkOnRebuildFromModuleInterface),
-    disableInterfaceLock(Opts.DisableInterfaceFileLock),
-    disableImplicitSwiftModule(Opts.DisableImplicitModules),
-    disableBuildingInterface(Opts.DisableBuildingInterface),
-    downgradeInterfaceVerificationError(Opts.DowngradeInterfaceVerificationError),
-    strictImplicitModuleContext(Opts.StrictImplicitModuleContext),
-    mainExecutablePath(Opts.MainExecutablePath)
-  {
-    switch (Opts.RequestedAction) {
-    case FrontendOptions::ActionType::TypecheckModuleFromInterface:
-      requestedAction = FrontendOptions::ActionType::Typecheck;
-      break;
-    case FrontendOptions::ActionType::ScanDependencies:
-      requestedAction = Opts.RequestedAction;
-      break;
-    default:
-      requestedAction = FrontendOptions::ActionType::EmitModuleOnly;
-      break;
-    }
-  }
+
+  ModuleInterfaceLoaderOptions(const FrontendOptions &Opts,
+                               bool inheritDebuggingOpts = false);
   ModuleInterfaceLoaderOptions() = default;
 };
 
diff --git a/lib/Frontend/ArgsToFrontendOptionsConverter.cpp b/lib/Frontend/ArgsToFrontendOptionsConverter.cpp
index 1fa65c581101b..22ed81daa6fe6 100644
--- a/lib/Frontend/ArgsToFrontendOptionsConverter.cpp
+++ b/lib/Frontend/ArgsToFrontendOptionsConverter.cpp
@@ -197,8 +197,11 @@ bool ArgsToFrontendOptionsConverter::convert(
   computeDebugTimeOptions();
   computeTBDOptions();
 
-  Opts.DumpClangLookupTables |= Args.hasArg(OPT_dump_clang_lookup_tables);
-  Opts.DumpAvailabilityScopes |= Args.hasArg(OPT_dump_availability_scopes);
+  Opts.CompilerDebuggingOpts.DumpAvailabilityScopes |=
+      Args.hasArg(OPT_dump_availability_scopes);
+
+  Opts.CompilerDebuggingOpts.DumpClangLookupTables |=
+      Args.hasArg(OPT_dump_clang_lookup_tables);
 
   Opts.CheckOnoneSupportCompleteness = Args.hasArg(OPT_check_onone_completeness);
 
@@ -472,7 +475,8 @@ void ArgsToFrontendOptionsConverter::handleDebugCrashGroupArguments() {
 void ArgsToFrontendOptionsConverter::computePrintStatsOptions() {
   using namespace options;
   Opts.PrintStats |= Args.hasArg(OPT_print_stats);
-  Opts.PrintClangStats |= Args.hasArg(OPT_print_clang_stats);
+  Opts.CompilerDebuggingOpts.PrintClangStats |=
+      Args.hasArg(OPT_print_clang_stats);
   Opts.PrintZeroStats |= Args.hasArg(OPT_print_zero_stats);
 #if defined(NDEBUG) && !LLVM_ENABLE_STATS
   if (Opts.PrintStats || Opts.PrintClangStats)
diff --git a/lib/Frontend/Frontend.cpp b/lib/Frontend/Frontend.cpp
index 5cadb6afe4fe1..c79192c88c1dd 100644
--- a/lib/Frontend/Frontend.cpp
+++ b/lib/Frontend/Frontend.cpp
@@ -18,6 +18,7 @@
 #include "swift/Frontend/Frontend.h"
 #include "swift/AST/ASTContext.h"
 #include "swift/AST/AvailabilityDomain.h"
+#include "swift/AST/AvailabilityScope.h"
 #include "swift/AST/DiagnosticsFrontend.h"
 #include "swift/AST/DiagnosticsSema.h"
 #include "swift/AST/FileSystem.h"
@@ -1867,6 +1868,23 @@ bool CompilerInstance::performSILProcessing(SILModule *silModule) {
   return false;
 }
 
+void CompilerInstance::emitEndOfPipelineDebuggingOutput() {
+  assert(hasASTContext());
+  auto &ctx = getASTContext();
+  const auto &Invocation = getInvocation();
+  const auto &opts = Invocation.getFrontendOptions().CompilerDebuggingOpts;
+
+  if (opts.PrintClangStats && ctx.getClangModuleLoader())
+    ctx.getClangModuleLoader()->printStatistics();
+
+  if (opts.DumpAvailabilityScopes)
+    getPrimaryOrMainSourceFile().getAvailabilityScope()->dump(llvm::errs(),
+                                                              ctx.SourceMgr);
+
+  if (opts.DumpClangLookupTables && ctx.getClangModuleLoader())
+    ctx.getClangModuleLoader()->dumpSwiftLookupTables();
+}
+
 bool CompilerInstance::isCancellationRequested() const {
   auto flag = getASTContext().CancellationFlag;
   return flag && flag->load(std::memory_order_relaxed);
diff --git a/lib/Frontend/ModuleInterfaceBuilder.cpp b/lib/Frontend/ModuleInterfaceBuilder.cpp
index ac50e5e7bfdfe..be3dd3520cfdd 100644
--- a/lib/Frontend/ModuleInterfaceBuilder.cpp
+++ b/lib/Frontend/ModuleInterfaceBuilder.cpp
@@ -203,6 +203,7 @@ std::error_code ExplicitModuleInterfaceBuilder::buildSwiftModuleFromInterface(
     ArrayRef<std::string> CompiledCandidates,
     StringRef CompilerVersion) {
   auto Invocation = Instance.getInvocation();
+
   // Try building forwarding module first. If succeed, return.
   if (Instance.getASTContext()
           .getModuleInterfaceChecker()
@@ -254,6 +255,9 @@ std::error_code ExplicitModuleInterfaceBuilder::buildSwiftModuleFromInterface(
                  builtByCompiler);
       }
     }
+
+    // If requested, dump debugging output before exiting.
+    Instance.emitEndOfPipelineDebuggingOutput();
   };
 
   Instance.performSema();
diff --git a/lib/Frontend/ModuleInterfaceLoader.cpp b/lib/Frontend/ModuleInterfaceLoader.cpp
index 98184ffc0d8d0..c2cc8dd445455 100644
--- a/lib/Frontend/ModuleInterfaceLoader.cpp
+++ b/lib/Frontend/ModuleInterfaceLoader.cpp
@@ -1294,6 +1294,34 @@ bool ModuleInterfaceCheckerImpl::isCached(StringRef DepPath) {
   return !PrebuiltCacheDir.empty() && DepPath.starts_with(PrebuiltCacheDir);
 }
 
+static FrontendOptions::ActionType
+reqestedModuleLoaderActionForFrontendOpts(const FrontendOptions &Opts) {
+  switch (Opts.RequestedAction) {
+  case FrontendOptions::ActionType::TypecheckModuleFromInterface:
+    return FrontendOptions::ActionType::Typecheck;
+  case FrontendOptions::ActionType::ScanDependencies:
+    return Opts.RequestedAction;
+  default:
+    return FrontendOptions::ActionType::EmitModuleOnly;
+  }
+}
+
+ModuleInterfaceLoaderOptions::ModuleInterfaceLoaderOptions(
+    const FrontendOptions &Opts, bool inheritDebuggingOpts)
+    : requestedAction(reqestedModuleLoaderActionForFrontendOpts(Opts)),
+      remarkOnRebuildFromInterface(Opts.RemarkOnRebuildFromModuleInterface),
+      disableInterfaceLock(Opts.DisableInterfaceFileLock),
+      disableImplicitSwiftModule(Opts.DisableImplicitModules),
+      disableBuildingInterface(Opts.DisableBuildingInterface),
+      downgradeInterfaceVerificationError(
+          Opts.DowngradeInterfaceVerificationError),
+      strictImplicitModuleContext(Opts.StrictImplicitModuleContext),
+      mainExecutablePath(Opts.MainExecutablePath) {
+  if (inheritDebuggingOpts) {
+    compilerDebuggingOptions = Opts.CompilerDebuggingOpts;
+  }
+}
+
 bool ModuleInterfaceLoader::isCached(StringRef DepPath) {
   return InterfaceChecker.isCached(DepPath);
 }
@@ -1870,6 +1898,7 @@ InterfaceSubContextDelegateImpl::InterfaceSubContextDelegateImpl(
   SubFEOpts.RequestedAction = LoaderOpts.requestedAction;
   SubFEOpts.StrictImplicitModuleContext =
       LoaderOpts.strictImplicitModuleContext;
+  SubFEOpts.CompilerDebuggingOpts = LoaderOpts.compilerDebuggingOptions;
   if (!moduleCachePath.empty()) {
     genericSubInvocation.setClangModuleCachePath(moduleCachePath);
   }
diff --git a/lib/FrontendTool/FrontendTool.cpp b/lib/FrontendTool/FrontendTool.cpp
index afa4b40087ae0..e9725e0de23e3 100644
--- a/lib/FrontendTool/FrontendTool.cpp
+++ b/lib/FrontendTool/FrontendTool.cpp
@@ -353,7 +353,8 @@ static bool buildModuleFromInterface(CompilerInstance &Instance) {
   assert(FEOpts.InputsAndOutputs.hasSingleInput());
   StringRef InputPath = FEOpts.InputsAndOutputs.getFilenameOfFirstInput();
   StringRef PrebuiltCachePath = FEOpts.PrebuiltModuleCachePath;
-  ModuleInterfaceLoaderOptions LoaderOpts(FEOpts);
+  ModuleInterfaceLoaderOptions LoaderOpts(FEOpts,
+                                          /*inheritDebuggingOpts=*/true);
   StringRef ABIPath = Instance.getPrimarySpecificPathsForAtMostOnePrimary()
                           .SupplementaryOutputs.ABIDescriptorOutputPath;
   bool IgnoreAdjacentModules = Instance.hasASTContext() &&
@@ -1021,25 +1022,16 @@ static void performEndOfPipelineActions(CompilerInstance &Instance) {
   const auto &Invocation = Instance.getInvocation();
   const auto &opts = Invocation.getFrontendOptions();
 
-  // If we were asked to print Clang stats, do so.
-  if (opts.PrintClangStats && ctx.getClangModuleLoader())
-    ctx.getClangModuleLoader()->printStatistics();
-
   // Report AST stats if needed.
   if (auto *stats = ctx.Stats)
     countASTStats(*stats, Instance);
 
-  if (opts.DumpClangLookupTables && ctx.getClangModuleLoader())
-    ctx.getClangModuleLoader()->dumpSwiftLookupTables();
-
-  if (opts.DumpAvailabilityScopes)
-    Instance.getPrimaryOrMainSourceFile().getAvailabilityScope()->dump(
-        llvm::errs(), Instance.getASTContext().SourceMgr);
-
   // Report mangling stats if there was no error.
   if (!ctx.hadError())
     Mangle::printManglingStats();
 
+  Instance.emitEndOfPipelineDebuggingOutput();
+
   // Make sure we didn't load a module during a parse-only invocation, unless
   // it's -emit-imported-modules, which can load modules.
   auto action = opts.RequestedAction;
diff --git a/test/ModuleInterface/availability-scopes.swift b/test/ModuleInterface/availability-scopes.swift
new file mode 100644
index 0000000000000..2985d88ada8e2
--- /dev/null
+++ b/test/ModuleInterface/availability-scopes.swift
@@ -0,0 +1,10 @@
+// RUN: %empty-directory(%t)
+
+// RUN: %target-swift-emit-module-interface(%t/Test.swiftinterface) %s -module-name Test
+// RUN: %target-swift-typecheck-module-from-interface(%t/Test.swiftinterface) -module-name Test -dump-availability-scopes 2>&1 | %FileCheck --strict-whitespace %s
+// RUN: %target-swift-frontend -compile-module-from-interface %t/Test.swiftinterface -o /dev/null -module-name Test -dump-availability-scopes 2>&1 | %FileCheck --strict-whitespace %s
+
+// CHECK: {{^}}(root {{.*}} file={{.*}}{{/|\\}}availability-scopes.swift.tmp{{/|\\}}Test.swiftinterface
+// CHECK: {{^}}  (decl {{.*}}unavailable=* decl=unavailable()
+@available(*, unavailable)
+public func unavailable() { }