IRGen: Also unique selectors in extended method types list

rdar://60778637

Author: aschwaighofer

lib/IRGen/GenClass.cpp

@@ -1644,12 +1644,15 @@ namespace {
     void buildExtMethodTypes(ConstantArrayBuilder &array,
                              ArrayRef<MethodDescriptor> methods) {
       assert(isBuildingProtocol());
-
+      llvm::StringSet<> uniqueSelectors;
       for (auto descriptor : methods) {
         assert(descriptor.getKind() == MethodDescriptor::Kind::Method &&
                "cannot emit descriptor for non-method");
         auto method = descriptor.getMethod();
-        array.add(getMethodTypeExtendedEncoding(IGM, method));
+        auto *encodingOrNullIfDuplicate =
+            getMethodTypeExtendedEncoding(IGM, method, uniqueSelectors);
+        if (encodingOrNullIfDuplicate != nullptr)
+          array.add(encodingOrNullIfDuplicate);
       }
     }
 

lib/IRGen/GenObjC.cpp

@@ -1409,7 +1409,13 @@ void irgen::emitObjCIVarInitDestroyDescriptor(
 
 llvm::Constant *
 irgen::getMethodTypeExtendedEncoding(IRGenModule &IGM,
-                                     AbstractFunctionDecl *method) {
+                                     AbstractFunctionDecl *method,
+                                     llvm::StringSet<> &uniqueSelectors) {
+  // Don't emit a selector twice.
+  Selector selector(method);
+  if (!uniqueSelectors.insert(selector.str()).second)
+    return nullptr;
+
   CanSILFunctionType methodType = getObjCMethodType(IGM, method);
   return getObjCEncodingForMethod(IGM, methodType, true /*Extended*/, method);
 }

lib/IRGen/GenObjC.h

@@ -177,10 +177,12 @@ namespace irgen {
                                                CanSILFunctionType invokeTy);
 
   /// Produces extended encoding of method type.
-  /// \returns the encoded type.
-  llvm::Constant *getMethodTypeExtendedEncoding(IRGenModule &IGM,
-                                                AbstractFunctionDecl *method);
-  
+  /// \returns the encoded type or null if it is a duplicate (exists in
+  /// \p uniqueSelectors).
+  llvm::Constant *
+  getMethodTypeExtendedEncoding(IRGenModule &IGM, AbstractFunctionDecl *method,
+                                llvm::StringSet<> &uniqueSelectors);
+
   /// Build an Objective-C method descriptor for the given getter method.
   void emitObjCGetterDescriptor(IRGenModule &IGM,
                                 ConstantArrayBuilder &descriptors,

test/IRGen/objc_protocol_instance_methods.swift

@@ -7,6 +7,9 @@
 
 // CHECK-NOT: _PROTOCOL_INSTANCE_METHODS_NSObject{{.*}}"\01L_selector_data(conformsToProtocol:)"{{.*}}"\01L_selector_data(conformsToProtocol:)"
 
+// Make sure that extended method types are in sync with entries in method list.
+// CHECK: @_PROTOCOL_INSTANCE_METHODS_NSObject = private constant { i32, i32, [5 x
+// CHECK: @_PROTOCOL_METHOD_TYPES_NSObject = private constant [5
 import Foundation
 
 @objc protocol P: NSObjectProtocol {}