Add a hidden flag to disable the swift bridge attribute

include/swift/ClangImporter/ClangImporterOptions.h

@@ -67,6 +67,9 @@ class ClangImporterOptions {
   /// member of some type instead. This includes inits, computed properties,
   /// and methods.
   bool InferImportAsMember = false;
+
+  /// If true ignore the swift bridged attribute.
+  bool DisableSwiftBridgeAttr = false;
 };
 
 } // end namespace swift

include/swift/Option/Options.td

@@ -218,6 +218,10 @@ def solver_memory_threshold : Separate<["-"], "solver-memory-threshold">,
   Flags<[FrontendOption, HelpHidden, DoesNotAffectIncrementalBuild]>,
   HelpText<"Set the upper bound for memory consumption, in bytes, by the constraint solver">;   
 
+def disable_swift_bridge_attr : Flag<["-"], "disable-swift-bridge-attr">,
+  Flags<[FrontendOption, HelpHidden]>,
+  HelpText<"Disable using the swift bridge attribute">;
+
 // Diagnostic control options
 def suppress_warnings : Flag<["-"], "suppress-warnings">,
   Flags<[FrontendOption, DoesNotAffectIncrementalBuild]>,

lib/ClangImporter/ClangImporter.cpp

@@ -1183,6 +1183,7 @@ ClangImporter::Implementation::Implementation(ASTContext &ctx,
   : SwiftContext(ctx),
     ImportForwardDeclarations(opts.ImportForwardDeclarations),
     InferImportAsMember(opts.InferImportAsMember),
+    DisableSwiftBridgeAttr(opts.DisableSwiftBridgeAttr),
     BridgingHeaderLookupTable(nullptr)
 {
   // Add filters to determine if a Clang availability attribute
@@ -1957,7 +1958,11 @@ namespace {
 /// Determine whether the given Objective-C class, or any of its
 /// superclasses, either has or inherits a swift_bridge attribute.
 static bool hasOrInheritsSwiftBridgeAttr(
-    const clang::ObjCInterfaceDecl *objcClass) {
+    const clang::ObjCInterfaceDecl *objcClass,
+    bool DisableSwiftBridgeAttr) {
+  // If we have disabled the attribute just return that there is none.
+  if (DisableSwiftBridgeAttr)
+    return false;
   do {
     // Look at the definition, if there is one.
     if (auto def = objcClass->getDefinition())
@@ -2481,7 +2486,8 @@ auto ClangImporter::Implementation::importFullName(
     if (D->getDeclContext()->getRedeclContext()->isFileContext() &&
         (isa<clang::TypeDecl>(D) ||
          (isa<clang::ObjCInterfaceDecl>(D) &&
-          !hasOrInheritsSwiftBridgeAttr(cast<clang::ObjCInterfaceDecl>(D))) ||
+          !hasOrInheritsSwiftBridgeAttr(cast<clang::ObjCInterfaceDecl>(D),
+                                        DisableSwiftBridgeAttr)) ||
          isa<clang::ObjCProtocolDecl>(D))) {
       // Find the original declaration, from which we can determine
       // the owning module.

lib/ClangImporter/ImportType.cpp

@@ -677,6 +677,8 @@ namespace {
     /// Map the Clang swift_bridge attribute to a specific type.
     Type mapSwiftBridgeAttr(const clang::NamedDecl *clangDecl) {
       // Check whether there is a swift_bridge attribute.
+      if (Impl.DisableSwiftBridgeAttr)
+        return Type();
       auto bridgeAttr = clangDecl->getAttr<clang::SwiftBridgeAttr>();
       if (!bridgeAttr) return Type();
 

lib/ClangImporter/ImporterImpl.h

@@ -262,6 +262,7 @@ class LLVM_LIBRARY_VISIBILITY ClangImporter::Implementation
 
   const bool ImportForwardDeclarations;
   const bool InferImportAsMember;
+  const bool DisableSwiftBridgeAttr;
 
   constexpr static const char * const moduleImportBufferName =
     "<swift-imported-modules>";

lib/Frontend/CompilerInvocation.cpp

@@ -884,6 +884,8 @@ static bool ParseClangImporterArgs(ClangImporterOptions &Opts,
   if (Args.hasArg(OPT_embed_bitcode))
     Opts.Mode = ClangImporterOptions::Modes::EmbedBitcode;
 
+  Opts.DisableSwiftBridgeAttr |= Args.hasArg(OPT_disable_swift_bridge_attr);
+
   return false;
 }
 

test/SILGen/objc_disable_brigding.swift

@@ -0,0 +1,18 @@
+// RUN: rm -rf %t && mkdir -p %t
+// RUN: %build-silgen-test-overlays
+// RUN: %target-swift-frontend -emit-module -o %t -sdk %S/Inputs -I %S/../Inputs/ObjCBridging %S/../Inputs/ObjCBridging/Appliances.swift -I %t
+// RUN: %target-swift-frontend(mock-sdk: -sdk %S/Inputs -I %t -I %S/../Inputs/ObjCBridging) -disable-swift-bridge-attr -Xllvm -sil-full-demangle -emit-silgen %s | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-%target-cpu --check-prefix=CHECK-%target-os-%target-cpu
+
+// REQUIRES: objc_interop
+
+import Foundation
+import Appliances
+
+// This tests the -disable-swift-bridge-attr flag. Make sure we don't emit bridging code.
+
+// CHECK-LABEL: sil hidden @{{.*}}objc_disable_brigding16updateFridgeTemp
+func updateFridgeTemp(home: APPHouse, delta: Double) {
+  // CHECK-NOT: function_ref @{{.*}}BridgeFromObjectiveC
+  home.fridge.temperature += delta
+// CHECK: return
+}