NFC, extract param & return type for type metadata access function to accessors for reuse

They will be reused to provide information about the signature of the type metadata access function to the Clang printer for C++ interop

Author: hyp

lib/IRGen/GenDecl.cpp

@@ -4352,6 +4352,14 @@ IRGenModule::getAddrOfObjCResilientClassStub(ClassDecl *classDecl,
   return getAddrOfLLVMVariable(entity, forDefinition, DebugTypeInfo());
 }
 
+llvm::IntegerType *IRGenModule::getTypeMetadataRequestParamTy() {
+  return SizeTy;
+}
+
+llvm::StructType *IRGenModule::getTypeMetadataResponseTy() {
+  return TypeMetadataResponseTy;
+}
+
 /// Fetch the type metadata access function for a non-generic type.
 llvm::Function *
 IRGenModule::getAddrOfTypeMetadataAccessFunction(CanType type,
@@ -4367,8 +4375,9 @@ IRGenModule::getAddrOfTypeMetadataAccessFunction(CanType type,
     return entry;
   }
 
-  llvm::Type *params[] = { SizeTy }; // MetadataRequest
-  auto fnType = llvm::FunctionType::get(TypeMetadataResponseTy, params, false);
+  llvm::Type *params[] = {getTypeMetadataRequestParamTy()}; // MetadataRequest
+  auto fnType =
+      llvm::FunctionType::get(getTypeMetadataResponseTy(), params, false);
   Signature signature(fnType, llvm::AttributeList(), SwiftCC);
   LinkInfo link = LinkInfo::get(*this, entity, forDefinition);
   entry = createFunction(*this, link, signature);

lib/IRGen/IRGenModule.h

@@ -874,6 +874,9 @@ class IRGenModule {
   llvm::PointerType *getValueWitnessTablePtrTy();
   llvm::PointerType *getEnumValueWitnessTablePtrTy();
 
+  llvm::IntegerType *getTypeMetadataRequestParamTy();
+  llvm::StructType *getTypeMetadataResponseTy();
+
   void unimplemented(SourceLoc, StringRef Message);
   [[noreturn]]
   void fatal_unimplemented(SourceLoc, StringRef Message);