Frontend: Remove support for -experimental-spi-imports flag.

Its functionality has been superseded by `@_spiOnly import`. There are no
longer any known clients and the flag was already unsupported in Swift 6, so
the functionality is now removed (but the flag is only deprecated for Swift 5).

Resolves rdar://136867210.

Author: tshortli

include/swift/AST/DiagnosticsFrontend.def

@@ -486,6 +486,7 @@ REMARK(interface_file_backup_used,none,
       "building module from '%0' failed; retrying building module from '%1'", (StringRef, StringRef))
 
 WARNING(warn_flag_deprecated,none, "flag '%0' is deprecated", (StringRef))
+ERROR(flag_unsuppored,none, "flag '%0' is unsupported", (StringRef))
 
 // Output deterministic check
 ERROR(error_nondeterministic_output,none,

include/swift/Frontend/ModuleInterfaceSupport.h

@@ -67,10 +67,6 @@ struct ModuleInterfaceOptions {
   /// Flags which appear only in the .package.swiftinterface.
   InterfaceFlags PackageFlags = {};
 
-  /// Print imports with both @_implementationOnly and @_spi, only applies
-  /// when PrintSPIs is true.
-  bool ExperimentalSPIImports = false;
-
   /// Print imports that are missing from the source and used in API.
   bool PrintMissingImports = true;
 

lib/Frontend/CompilerInvocation.cpp

@@ -519,8 +519,6 @@ static void ParseModuleInterfaceArgs(ModuleInterfaceOptions &Opts,
                  ::getenv("SWIFT_ALIAS_MODULE_NAMES_IN_INTERFACES"));
   Opts.PrintFullConvention |=
     Args.hasArg(OPT_experimental_print_full_convention);
-  Opts.ExperimentalSPIImports |=
-    Args.hasArg(OPT_experimental_spi_imports);
   Opts.DebugPrintInvalidSyntax |=
     Args.hasArg(OPT_debug_emit_invalid_swiftinterface_syntax);
   Opts.PrintMissingImports =
@@ -1193,6 +1191,16 @@ static bool ParseLangArgs(LangOptions &Opts, ArgList &Args,
   }
 
   Opts.EnableSPIOnlyImports = Args.hasArg(OPT_experimental_spi_only_imports);
+  if (Args.hasArg(OPT_experimental_spi_imports)) {
+    if (Opts.EffectiveLanguageVersion.isVersionAtLeast(6)) {
+      Diags.diagnose(SourceLoc(), diag::flag_unsuppored,
+                     "-experimental-spi-imports");
+      HadError = true;
+    } else {
+      Diags.diagnose(SourceLoc(), diag::warn_flag_deprecated,
+                     "-experimental-spi-imports");
+    }
+  }
 
   if (Args.hasArg(OPT_warn_swift3_objc_inference_minimal))
     Diags.diagnose(SourceLoc(), diag::warn_flag_deprecated,
@@ -3733,15 +3741,10 @@ bool CompilerInvocation::parseArgs(
     }
   }
 
-  // With Swift 6, enable @_spiOnly by default and forbid the old version.
-  // This also enables proper error reporting of ioi references from spi decls.
+  // With Swift 6, enable @_spiOnly by default. This also enables proper error
+  // reporting of ioi references from spi decls.
   if (LangOpts.EffectiveLanguageVersion.isVersionAtLeast(6)) {
     LangOpts.EnableSPIOnlyImports = true;
-
-    if (ParsedArgs.hasArg(OPT_experimental_spi_imports)) {
-      Diags.diagnose(SourceLoc(), diag::error_old_spi_only_import_unsupported);
-      return true;
-    }
   }
 
   return false;

lib/Frontend/ModuleInterfaceSupport.cpp

@@ -279,27 +279,6 @@ static void printImports(raw_ostream &out,
     return importSet;
   };
 
-  // With -experimental-spi-imports:
-  // When printing the private or package swiftinterface file, print implementation-only
-  // imports only if they are also SPI. First, list all implementation-only imports and
-  // filter them later.
-  llvm::SmallSet<ImportedModule, 4, ImportedModule::Order> ioiImportSet;
-  if (!Opts.printPublicInterface() && Opts.ExperimentalSPIImports) {
-
-    SmallVector<ImportedModule, 4> ioiImports, allImports;
-    M->getImportedModules(ioiImports,
-                          ModuleDecl::ImportFilterKind::ImplementationOnly);
-
-    // Only consider modules imported consistently as implementation-only.
-    ImportSet allImportSet = getImports(allImportFilter);
-
-    for (auto import: ioiImports)
-      if (allImportSet.count(import) == 0)
-        ioiImportSet.insert(import);
-
-    allImportFilter |= ModuleDecl::ImportFilterKind::ImplementationOnly;
-  }
-
   /// Collect @_spiOnly imports that are not imported elsewhere publicly.
   ImportSet spiOnlyImportSet;
   if (!Opts.printPublicInterface()) {
@@ -367,13 +346,6 @@ static void printImports(raw_ostream &out,
     llvm::SmallSetVector<Identifier, 4> spis;
     M->lookupImportedSPIGroups(importedModule, spis);
 
-    // Only print implementation-only imports which have an SPI import.
-    if (ioiImportSet.count(import)) {
-      if (spis.empty())
-        continue;
-      out << "@_implementationOnly ";
-    }
-
     if (exportedImportSet.count(import))
       out << "@_exported ";
 

test/SPI/experimental_spi_imports_swiftinterface.swift

@@ -1,46 +1,11 @@
-/// Test the textual interfaces generated with -experimental-spi-imports.
+// RUN: %target-swift-frontend -typecheck %s -swift-version 5 \
+// RUN:   -experimental-spi-imports 2>&1 | %FileCheck %s -check-prefix=CHECK-5
 
-// RUN: %empty-directory(%t)
-
-/// Generate 3 empty modules.
-// RUN: touch %t/empty.swift
-// RUN: %target-swift-frontend -emit-module %S/Inputs/ioi_helper.swift -module-name ExperimentalImported -emit-module-path %t/ExperimentalImported.swiftmodule -swift-version 5 -enable-library-evolution
-// RUN: %target-swift-frontend -emit-module %t/empty.swift -module-name IOIImported -emit-module-path %t/IOIImported.swiftmodule -swift-version 5 -enable-library-evolution
-// RUN: %target-swift-frontend -emit-module %t/empty.swift -module-name SPIImported -emit-module-path %t/SPIImported.swiftmodule -swift-version 5 -enable-library-evolution
-// RUN: %target-swift-frontend -emit-module %t/empty.swift -module-name InconsistentlyImported -emit-module-path %t/InconsistentlyImported.swiftmodule -swift-version 5 -enable-library-evolution
-
-/// Test the generated swiftinterface.
-// RUN: %target-swift-frontend -typecheck %s %S/Inputs/experimental_spi_imports_inconsistent.swift -emit-module-interface-path %t/main.swiftinterface -emit-private-module-interface-path %t/main.private.swiftinterface -enable-library-evolution -swift-version 5 -I %t -experimental-spi-imports
-// RUN: %target-swift-typecheck-module-from-interface(%t/main.swiftinterface) -I %t
-// RUN: %target-swift-typecheck-module-from-interface(%t/main.private.swiftinterface) -I %t
-// RUN: %FileCheck -check-prefix=CHECK-PUBLIC %s < %t/main.swiftinterface
-// RUN: %FileCheck -check-prefix=CHECK-PRIVATE %s < %t/main.private.swiftinterface
-
-/// The flag is rejected in Swift 6.
-// RUN: not %target-swift-frontend -typecheck % -swift-version 6 \
+// RUN: not %target-swift-frontend -typecheck %s -swift-version 6 \
 // RUN:   -experimental-spi-imports 2>&1 | %FileCheck %s -check-prefix=CHECK-6
-// CHECK-6: error: '-experimental-spi-imports' is unsupported in Swift 6, use '@_spiOnly' instead
 
-@_spi(dummy) @_implementationOnly import ExperimentalImported
-// CHECK-PUBLIC-NOT: import ExperimentalImported
-// CHECK-PRIVATE: @_implementationOnly @_spi{{.*}} import ExperimentalImported
+/// The flag is deprecated before Swift 6.
+// CHECK-5: flag '-experimental-spi-imports' is deprecated
 
-// This is also imported as implementation-only via another source file.
-import InconsistentlyImported
-// CHECK-PUBLIC: {{^}}import InconsistentlyImported
-// CHECK-PRIVATE: {{^}}import InconsistentlyImported
-
-@_implementationOnly import IOIImported
-// CHECK-PUBLIC-NOT: IOIImported
-// CHECK-PRIVATE-NOT: IOIImported
-
-@_spi(dummy) import SPIImported
-// CHECK-PUBLIC: {{^}}import SPIImported
-// CHECK-PRIVATE: @_spi{{.*}} import SPIImported
-
-@_spi(X)
-extension IOIPublicStruct {
-  public func foo() {}
-}
-// CHECK-PUBLIC-NOT: ExperimentalImported.IOIPublicStruct
-// CHECK-PRIVATE: @_spi{{.*}} extension ExperimentalImported.IOIPublicStruct
+/// The flag is rejected in Swift 6.
+// CHECK-6: flag '-experimental-spi-imports' is unsupported