[Distributed] thread-safety also for parameter type metadata

We had fixed this bug in https://github.com/swiftlang/swift/pull/79381
but missed to realize the same problem existed for parameters as well.

This corrects the swift_func_getParameterTypeInfo impl, and also removes
the entire "unsafe" method, we no longer use it anywhere.

Resolves rdar://146679254

stdlib/public/runtime/MetadataLookup.cpp

@@ -2907,25 +2907,6 @@ static NodePointer getParameterList(NodePointer funcType) {
   return parameterContainer;
 }
 
-static const Metadata *decodeType(TypeDecoder<DecodedMetadataBuilder> &decoder,
-                                  NodePointer type) {
-  assert(type->getKind() == Node::Kind::Type);
-
-  auto builtTypeOrError = decoder.decodeMangledType(type);
-
-  if (builtTypeOrError.isError()) {
-    auto err = builtTypeOrError.getError();
-    char *errStr = err->copyErrorString();
-    err->freeErrorString(errStr);
-    return nullptr;
-  }
-
-  if (!builtTypeOrError.getType().isMetadata())
-    return nullptr;
-
-  return builtTypeOrError.getType().getMetadata();
-}
-
 SWIFT_CC(swift)
 SWIFT_RUNTIME_STDLIB_SPI
 unsigned swift_func_getParameterCount(const char *typeNameStart,
@@ -3009,8 +2990,21 @@ swift_func_getParameterTypeInfo(
 
   SubstGenericParametersFromMetadata substFn(genericEnv, genericArguments);
 
-  DecodedMetadataBuilder builder(
-      demangler,
+  // for each parameter (TupleElement), store it into the provided buffer
+  for (unsigned index = 0; index != typesLength; ++index) {
+    auto nodePointer = parameterList->getChild(index);
+
+    if (nodePointer->getKind() == Node::Kind::TupleElement) {
+      assert(nodePointer->getNumChildren() == 1);
+      nodePointer = nodePointer->getFirstChild();
+    }
+    assert(nodePointer->getKind() == Node::Kind::Type);
+
+    auto request = MetadataRequest(MetadataState::Complete);
+
+    auto typeInfoOrErr = swift_getTypeByMangledNode(
+      request, demangler, nodePointer,
+      /*arguments=*/genericArguments,
       /*substGenericParam=*/
       [&substFn](unsigned depth, unsigned index) {
         return substFn.getMetadata(depth, index).Ptr;
@@ -3019,24 +3013,13 @@ swift_func_getParameterTypeInfo(
       [&substFn](const Metadata *type, unsigned index) {
         return substFn.getWitnessTable(type, index);
       });
-  TypeDecoder<DecodedMetadataBuilder> decoder(builder);
 
-  // for each parameter (TupleElement), store it into the provided buffer
-  for (unsigned index = 0; index != typesLength; ++index) {
-    auto *parameter = parameterList->getChild(index);
-
-    if (parameter->getKind() == Node::Kind::TupleElement) {
-      assert(parameter->getNumChildren() == 1);
-      parameter = parameter->getFirstChild();
+    if (typeInfoOrErr.isError()) {
+      return -3; // Failed to decode a type.
     }
 
-    assert(parameter->getKind() == Node::Kind::Type);
-
-    auto type = decodeType(decoder, parameter);
-    if (!type)
-      return -3; // Failed to decode a type.
-
-    types[index] = type;
+    auto typeInfo = typeInfoOrErr.getType();
+    types[index] = typeInfo.getMetadata();
   } // end foreach parameter
 
   return typesLength;

test/Distributed/Runtime/distributed_actor_func_calls_without_touching_returnType_metadata_first.swift

@@ -1,8 +1,9 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-swift-frontend-emit-module -emit-module-path %t/FakeDistributedActorSystems.swiftmodule -module-name FakeDistributedActorSystems -target %target-swift-5.7-abi-triple %S/../Inputs/FakeDistributedActorSystems.swift
 // RUN: %target-build-swift -module-name dist -target %target-swift-5.7-abi-triple -parse-as-library -j2 -parse-as-library -plugin-path %swift-plugin-dir -I %t %s %S/../Inputs/FakeDistributedActorSystems.swift -o %t/a.out
 // RUN: %target-codesign %t/a.out
-// RUN: %target-run %t/a.out
+
+// RUN: %target-run %t/a.out PARAMETER_TYPE
+// RUN: %target-run %t/a.out RETURN_TYPE
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
@@ -17,7 +18,6 @@
 
 import Darwin
 import Distributed
-import FakeDistributedActorSystems
 import Foundation
 
 typealias DefaultDistributedActorSystem = FakeRoundtripActorSystem
@@ -1052,20 +1052,39 @@ struct BigGeneric<T>: Codable {
 }
 
 distributed actor D {
+  public distributed func getBigGeneric(_ value: BigGeneric<TypeXXXX>) {}
   public distributed func getBigGeneric() -> BigGeneric<TypeXXXX> {
-    return BigGeneric()
-  }
+     return BigGeneric()
+   }
 }
 
-func attempt(n: Int) {
-  var fname = "$s4dist1DC13getBigGenericAA0cD0VyAA8Type\(n)VGyF"
+func attempt(_ mode: Mode, n: Int) {
+  var funcName_returnType = "$s4dist1DC13getBigGenericAA0cD0VyAA8Type\(n)VGyF"
+  var funcName_param = "$s4dist1DC13getBigGenericyyAA0cD0VyAA8Type\(n)VGF"
 
   func tryLookup() {
-    let t = fname.withUTF8 {
-      __getReturnTypeInfo($0.baseAddress!, UInt($0.count), nil, nil)
-    }
+    let t: (any Any.Type)? =
+      switch mode {
+      case .returnType:
+        funcName_returnType.withUTF8 {
+          __getReturnTypeInfo($0.baseAddress!, UInt($0.count), nil, nil)
+        }
+
+      case .paramType:
+        funcName_param.withUTF8 { nameBuf in
+          var type: Any.Type?
+          withUnsafeMutablePointer(to: &type) { typePtr in
+            let ret = __getParameterTypeInfo(nameBuf.baseAddress!, UInt(nameBuf.count), nil, nil, typePtr._rawValue, 1)
+            if ret != 1 {
+              fatalError("Decoded \(ret) parameters, expected 1")
+            }
+          }
+          return type
+        }
+      }
+
     guard let t else {
-      print("couldn't look up type for: \(fname)")
+      print("couldn't look up type for mode: \(mode)")
       exit(1)
     }
     func examineType<T>(_t: T.Type) {
@@ -1081,10 +1100,23 @@ func attempt(n: Int) {
   }
 }
 
+enum Mode: String {
+  case returnType = "RETURN_TYPE"
+  case paramType = "PARAMETER_TYPE"
+}
+
 @main struct Main {
   static func main() {
-    for i in 1000...1999 {
-      attempt(n: i)
+    if CommandLine.arguments.count < 2 {
+      fatalError("Expected explicit mode in command line arguments, was: \(CommandLine.arguments)")
     }
+
+    let mode = Mode.init(rawValue: CommandLine.arguments.dropFirst().first!)!
+    print("Checking in mode: \(mode)...")
+
+    for i in 1000...1999 {
+      attempt(mode, n: i)
+    }
+    print("Passed in mode: \(mode)!")
   }
-}
+}