Add a flag to enable/disable usage of objective c protocol symbolic references

Author: aschwaighofer

include/swift/AST/IRGenOptions.h

@@ -399,6 +399,8 @@ class IRGenOptions {
   /// Enable runtime instantiation of value witness strings for generic types
   unsigned EnableLayoutStringValueWitnessesInstantiation : 1;
 
+  unsigned EnableObjectiveCProtocolSymbolicReferences : 1;
+
   /// Instrument code to generate profiling information.
   unsigned GenerateProfile : 1;
 
@@ -518,6 +520,7 @@ class IRGenOptions {
         UseTypeLayoutValueHandling(true), ForceStructTypeLayouts(false),
         EnableLayoutStringValueWitnesses(false),
         EnableLayoutStringValueWitnessesInstantiation(false),
+        EnableObjectiveCProtocolSymbolicReferences(false),
         GenerateProfile(false), EnableDynamicReplacementChaining(false),
         DisableDebuggerShadowCopies(false),
         DisableConcreteTypeMetadataMangledNameAccessors(false),

include/swift/Option/FrontendOptions.td

@@ -1233,6 +1233,13 @@ def disable_new_llvm_pass_manager :
   Flag<["-"], "disable-new-llvm-pass-manager">,
   HelpText<"Disable the new llvm pass manager">;
 
+def enable_objective_c_protocol_symbolic_references :
+  Flag<["-"], "enable-objective-c-protocol-symbolic-references">,
+  HelpText<"Enable objective-c protocol symbolic references">;
+def disable_objective_c_protocol_symbolic_references :
+  Flag<["-"], "disable-objective-c-protocol-symbolic-references">,
+  HelpText<"Disable objective-c protocol symbolic references">;
+
 def disable_emit_generic_class_ro_t_list :
   Flag<["-"], "disable-emit-generic-class-ro_t-list">,
   HelpText<"Disable emission of a section with references to class_ro_t of "

lib/Frontend/CompilerInvocation.cpp

@@ -2927,6 +2927,11 @@ static bool ParseIRGenArgs(IRGenOptions &Opts, ArgList &Args,
     return true;
   }
 
+  Opts.EnableObjectiveCProtocolSymbolicReferences =
+    Args.hasFlag(OPT_enable_objective_c_protocol_symbolic_references,
+                 OPT_disable_objective_c_protocol_symbolic_references,
+                 Opts.EnableObjectiveCProtocolSymbolicReferences);
+
   if (const Arg *A = Args.getLastArg(options::OPT_platform_c_calling_convention)) {
     Opts.PlatformCCallingConvention =
       llvm::StringSwitch<llvm::CallingConv::ID>(A->getValue())

lib/IRGen/IRGenModule.cpp

@@ -1936,6 +1936,8 @@ bool IRGenModule::shouldPrespecializeGenericMetadata() {
 }
 
 bool IRGenModule::canUseObjCSymbolicReferences() {
+  if (!IRGen.Opts.EnableObjectiveCProtocolSymbolicReferences)
+    return false;
   auto &context = getSwiftModule()->getASTContext();
   auto deploymentAvailability =
       AvailabilityContext::forDeploymentTarget(context);

test/IRGen/objc_protocol_symbolic_reference.swift

@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -target %target-future-triple -enable-objc-interop -emit-ir -primary-file %s -disable-objc-attr-requires-foundation-module | %FileCheck %s
+// RUN: %target-swift-frontend -enable-objective-c-protocol-symbolic-references -target %target-future-triple -enable-objc-interop -emit-ir -primary-file %s -disable-objc-attr-requires-foundation-module | %FileCheck %s
 
 // REQUIRES: PTRSIZE=64
 // REQIURES: objc_interop

test/Interpreter/objc_protocol_symbolic_reference.swift

@@ -1,5 +1,5 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-build-swift  -target %target-future-triple %s -module-name main -o %t/main
+// RUN: %target-build-swift -Xfrontend -enable-objective-c-protocol-symbolic-references -target %target-future-triple %s -module-name main -o %t/main
 // RUN: %target-codesign %t/main
 // RUN: %target-run %t/main | %FileCheck %s
 

test/Reflection/typeref_decoding_objc.swift

@@ -5,7 +5,7 @@
 // Test objective c symbolic references
 
 // RUN: %empty-directory(%t)
-// RUN: %target-build-swift -target %target-future-triple %S/Inputs/ObjectiveCTypes.swift -parse-as-library -emit-module -emit-library -module-name TypesToReflect -o %t/%target-library-name(TypesToReflect)
+// RUN: %target-build-swift -Xfrontend -enable-objective-c-protocol-symbolic-references -target %target-future-triple %S/Inputs/ObjectiveCTypes.swift -parse-as-library -emit-module -emit-library -module-name TypesToReflect -o %t/%target-library-name(TypesToReflect)
 // RUN: %target-swift-reflection-dump %t/%target-library-name(TypesToReflect) | %FileCheck %s --check-prefix=CHECK-%target-ptrsize --check-prefix=CHECK
 
 // REQUIRES: objc_interop