[Distributed] Implement distributed method accessors

docs/ABI/Mangling.rst

@@ -143,6 +143,7 @@ Globals
     global ::= opaque-type 'Ho'          // opaque type descriptor runtime record
   #endif
   global ::= protocol-conformance 'Hc'   // protocol conformance runtime record
+  global ::= global 'HF'                 // accessible function runtime record
 
   global ::= nominal-type 'Mo'           // class metadata immediate member base offset
 
@@ -218,6 +219,7 @@ types where the metadata itself has unknown layout.)
   global ::= global 'TD'                 // dynamic dispatch thunk
   global ::= global 'Td'                 // direct method reference thunk
   global ::= global 'TE'                 // distributed actor thunk
+  global ::= global 'TF'                 // distributed method accessor
   global ::= global 'TI'                 // implementation of a dynamic_replaceable function
   global ::= global 'Tu'                 // async function pointer of a function
   global ::= global 'TX'                 // function pointer of a dynamic_replaceable function

include/swift/ABI/Metadata.h

@@ -5036,6 +5036,30 @@ class DynamicReplacementScope
   uint32_t getFlags() { return flags; }
 };
 
+/// An "accessible" function that can be looked up based on a string key,
+/// and then called through a fully-abstracted entry point whose arguments
+/// can be constructed in code.
+template <typename Runtime>
+struct TargetAccessibleFunctionRecord final {
+public:
+  /// The name of the function, which is a unique string assigned to the
+  /// function so it can be looked up later.
+  RelativeDirectPointer<const char, /*nullable*/ false> Name;
+
+  /// The Swift function type, encoded as a mangled name.
+  RelativeDirectPointer<const char, /*nullable*/ false> FunctionType;
+
+  /// The fully-abstracted function to call.
+  ///
+  /// Could be a sync or async function pointer depending on flags.
+  RelativeDirectPointer<void *, /*nullable*/ false> Function;
+
+  /// Flags providing more information about the function.
+  AccessibleFunctionFlags Flags;
+};
+
+using AccessibleFunctionRecord = TargetAccessibleFunctionRecord<InProcess>;
+
 } // end namespace swift
 
 #pragma clang diagnostic pop

include/swift/ABI/MetadataValues.h

@@ -2312,6 +2312,21 @@ enum class ContinuationStatus : size_t {
   Resumed = 2
 };
 
+/// Flags that go in a TargetAccessibleFunction structure.
+class AccessibleFunctionFlags : public FlagSet<uint32_t> {
+public:
+  enum {
+    /// Whether this is a "distributed" actor function.
+    Distributed = 0,
+  };
+
+  explicit AccessibleFunctionFlags(uint32_t bits) : FlagSet(bits) {}
+  constexpr AccessibleFunctionFlags() {}
+
+  /// Whether the this is a "distributed" actor function.
+  FLAGSET_DEFINE_FLAG_ACCESSORS(Distributed, isDistributed, setDistributed)
+};
+
 } // end namespace swift
 
 #endif // SWIFT_ABI_METADATAVALUES_H

include/swift/AST/ASTMangler.h

@@ -104,6 +104,8 @@ class ASTMangler : public Mangler {
     SwiftAsObjCThunk,
     ObjCAsSwiftThunk,
     DistributedThunk,
+    DistributedMethodAccessor,
+    AccessibleFunctionRecord
   };
 
   ASTMangler(bool DWARFMangling = false)

include/swift/Demangling/DemangleNodes.def

@@ -71,6 +71,7 @@ CONTEXT_NODE(Destructor)
 CONTEXT_NODE(DidSet)
 NODE(Directness)
 NODE(DistributedThunk)
+NODE(DistributedMethodAccessor)
 NODE(DynamicAttribute)
 NODE(DirectMethodReferenceAttribute)
 NODE(DynamicSelf)
@@ -325,5 +326,8 @@ NODE(IndexSubset)
 NODE(AsyncAwaitResumePartialFunction)
 NODE(AsyncSuspendResumePartialFunction)
 
+// Added in Swift 5.6
+NODE(AccessibleFunctionRecord)
+
 #undef CONTEXT_NODE
 #undef NODE

include/swift/IRGen/Linking.h

@@ -481,6 +481,16 @@ class LinkEntity {
     /// name is known.
     /// The pointer is a const char* of the name.
     KnownAsyncFunctionPointer,
+
+    /// The pointer is SILFunction*
+    DistributedMethodAccessor,
+    /// An async function pointer for a distributed method accessor.
+    /// The pointer is a SILFunction*.
+    DistributedMethodAccessorAsyncPointer,
+
+    /// Accessible function record, which describes a function that can be
+    /// looked up by name by the runtime.
+    AccessibleFunctionRecord,
   };
   friend struct llvm::DenseMapInfo<LinkEntity>;
 
@@ -1236,6 +1246,13 @@ class LinkEntity {
           Kind, unsigned(LinkEntity::Kind::PartialApplyForwarderAsyncFunctionPointer));
       break;
 
+    case LinkEntity::Kind::DistributedMethodAccessor: {
+      entity.Data = LINKENTITY_SET_FIELD(
+          Kind,
+          unsigned(LinkEntity::Kind::DistributedMethodAccessorAsyncPointer));
+      break;
+    }
+
     default:
       llvm_unreachable("Link entity kind cannot have an async function pointer");
     }
@@ -1263,6 +1280,24 @@ class LinkEntity {
     return entity;
   }
 
+  static LinkEntity forDistributedMethodAccessor(SILFunction *method) {
+    LinkEntity entity;
+    entity.Pointer = method;
+    entity.SecondaryPointer = nullptr;
+    entity.Data =
+        LINKENTITY_SET_FIELD(Kind, unsigned(Kind::DistributedMethodAccessor));
+    return entity;
+  }
+
+  static LinkEntity forAccessibleFunctionRecord(SILFunction *func) {
+    LinkEntity entity;
+    entity.Pointer = func;
+    entity.SecondaryPointer = nullptr;
+    entity.Data =
+        LINKENTITY_SET_FIELD(Kind, unsigned(Kind::AccessibleFunctionRecord));
+    return entity;
+  }
+
   LinkEntity getUnderlyingEntityForAsyncFunctionPointer() const {
     LinkEntity entity;
     entity.Pointer = Pointer;
@@ -1294,6 +1329,11 @@ class LinkEntity {
           Kind, unsigned(LinkEntity::Kind::PartialApplyForwarder));
       break;
 
+    case LinkEntity::Kind::DistributedMethodAccessorAsyncPointer:
+      entity.Data = LINKENTITY_SET_FIELD(
+          Kind, unsigned(LinkEntity::Kind::DistributedMethodAccessor));
+      break;
+
     default:
       llvm_unreachable("Link entity is not an async function pointer");
     }
@@ -1341,7 +1381,9 @@ class LinkEntity {
     return getKind() == Kind::AsyncFunctionPointer ||
            getKind() == Kind::DynamicallyReplaceableFunctionVariable ||
            getKind() == Kind::DynamicallyReplaceableFunctionKey ||
-           getKind() == Kind::SILFunction;
+           getKind() == Kind::SILFunction ||
+           getKind() == Kind::DistributedMethodAccessor ||
+           getKind() == Kind::AccessibleFunctionRecord;
   }
 
   SILFunction *getSILFunction() const {

include/swift/Runtime/AccessibleFunction.h

@@ -0,0 +1,34 @@
+//===---- AcceesibleFunction.h - Runtime accessible functions ---*- C++ -*-===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2021 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+//
+// The runtime interface for functions accessible by name.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef SWIFT_RUNTIME_ACCESSIBLE_FUNCTION_H
+#define SWIFT_RUNTIME_ACCESSIBLE_FUNCTION_H
+
+#include "swift/ABI/Metadata.h"
+
+#include <cstdint>
+
+namespace swift {
+namespace runtime {
+
+SWIFT_RUNTIME_STDLIB_SPI const AccessibleFunctionRecord *
+swift_findAccessibleFunction(const char *targetNameStart,
+                             size_t targetNameLength);
+
+} // end namespace runtime
+} // end namespace swift
+
+#endif

include/swift/SIL/SILFunction.h

@@ -59,6 +59,10 @@ enum IsExactSelfClass_t {
   IsNotExactSelfClass,
   IsExactSelfClass,
 };
+enum IsDistributed_t {
+  IsNotDistributed,
+  IsDistributed,
+};
 
 enum class PerformanceConstraints : uint8_t {
   None = 0,
@@ -294,6 +298,9 @@ class SILFunction
   /// invoked with a `self` argument of the exact base class type.
   unsigned ExactSelfClass : 1;
 
+  /// Check whether this is a distributed method.
+  unsigned IsDistributed : 1;
+
   /// True if this function is inlined at least once. This means that the
   /// debug info keeps a pointer to this function.
   unsigned Inlined : 1;
@@ -373,14 +380,16 @@ class SILFunction
               SubclassScope classSubclassScope, Inline_t inlineStrategy,
               EffectsKind E, const SILDebugScope *debugScope,
               IsDynamicallyReplaceable_t isDynamic,
-              IsExactSelfClass_t isExactSelfClass);
+              IsExactSelfClass_t isExactSelfClass,
+              IsDistributed_t isDistributed);
 
   static SILFunction *
   create(SILModule &M, SILLinkage linkage, StringRef name,
          CanSILFunctionType loweredType, GenericEnvironment *genericEnv,
          Optional<SILLocation> loc, IsBare_t isBareSILFunction,
          IsTransparent_t isTrans, IsSerialized_t isSerialized,
          ProfileCounter entryCount, IsDynamicallyReplaceable_t isDynamic,
+         IsDistributed_t isDistributed,
          IsExactSelfClass_t isExactSelfClass,
          IsThunk_t isThunk = IsNotThunk,
          SubclassScope classSubclassScope = SubclassScope::NotApplicable,
@@ -399,7 +408,8 @@ class SILFunction
                          Inline_t inlineStrategy, EffectsKind E,
                          const SILDebugScope *DebugScope,
                          IsDynamicallyReplaceable_t isDynamic,
-                         IsExactSelfClass_t isExactSelfClass);
+                         IsExactSelfClass_t isExactSelfClass,
+                         IsDistributed_t isDistributed);
 
   /// Set has ownership to the given value. True means that the function has
   /// ownership, false means it does not.
@@ -747,6 +757,14 @@ class SILFunction
     ExactSelfClass = t;
   }
 
+  IsDistributed_t isDistributed() const {
+    return IsDistributed_t(IsDistributed);
+  }
+  void
+  setIsDistributed(IsDistributed_t value = IsDistributed_t::IsDistributed) {
+    IsDistributed = value;
+  }
+
   /// Get the DeclContext of this function.
   DeclContext *getDeclContext() const { return DeclCtxt; }
 

include/swift/SIL/SILFunctionBuilder.h

@@ -67,14 +67,16 @@ class SILFunctionBuilder {
                                          IsSerialized_t isSerialized,
                                          ProfileCounter entryCount,
                                          IsThunk_t isThunk,
-                                         IsDynamicallyReplaceable_t isDynamic);
+                                         IsDynamicallyReplaceable_t isDynamic,
+                                         IsDistributed_t isDistributed);
 
   /// Return the declaration of a function, or create it if it doesn't exist.
   SILFunction *getOrCreateFunction(
       SILLocation loc, StringRef name, SILLinkage linkage,
       CanSILFunctionType type, IsBare_t isBareSILFunction,
       IsTransparent_t isTransparent, IsSerialized_t isSerialized,
       IsDynamicallyReplaceable_t isDynamic,
+      IsDistributed_t isDistributed,
       ProfileCounter entryCount = ProfileCounter(),
       IsThunk_t isThunk = IsNotThunk,
       SubclassScope subclassScope = SubclassScope::NotApplicable);
@@ -102,6 +104,7 @@ class SILFunctionBuilder {
                  Optional<SILLocation> loc, IsBare_t isBareSILFunction,
                  IsTransparent_t isTrans, IsSerialized_t isSerialized,
                  IsDynamicallyReplaceable_t isDynamic,
+                 IsDistributed_t isDistributed,
                  ProfileCounter entryCount = ProfileCounter(),
                  IsThunk_t isThunk = IsNotThunk,
                  SubclassScope subclassScope = SubclassScope::NotApplicable,

include/swift/SIL/TypeSubstCloner.h

@@ -446,7 +446,7 @@ class TypeSubstCloner : public SILClonerWithScopes<ImplClass> {
           ParentFunction->getLocation(), MangledName, SILLinkage::Shared,
           ParentFunction->getLoweredFunctionType(), ParentFunction->isBare(),
           ParentFunction->isTransparent(), ParentFunction->isSerialized(),
-          IsNotDynamic, 0, ParentFunction->isThunk(),
+          IsNotDynamic, IsNotDistributed, 0, ParentFunction->isThunk(),
           ParentFunction->getClassSubclassScope());
       // Increment the ref count for the inlined function, so it doesn't
       // get deleted before we can emit abstract debug info for it.

lib/AST/ASTMangler.cpp

@@ -849,6 +849,8 @@ void ASTMangler::appendSymbolKind(SymbolKind SKind) {
     case SymbolKind::SwiftAsObjCThunk: return appendOperator("To");
     case SymbolKind::ObjCAsSwiftThunk: return appendOperator("TO");
     case SymbolKind::DistributedThunk: return appendOperator("TE");
+    case SymbolKind::DistributedMethodAccessor: return appendOperator("TF");
+    case SymbolKind::AccessibleFunctionRecord: return appendOperator("HF");
   }
 }
 

lib/Demangling/Demangler.cpp

@@ -133,12 +133,14 @@ bool swift::Demangle::isFunctionAttr(Node::Kind kind) {
     case Node::Kind::OutlinedBridgedMethod:
     case Node::Kind::MergedFunction:
     case Node::Kind::DistributedThunk:
+    case Node::Kind::DistributedMethodAccessor:
     case Node::Kind::DynamicallyReplaceableFunctionImpl:
     case Node::Kind::DynamicallyReplaceableFunctionKey:
     case Node::Kind::DynamicallyReplaceableFunctionVar:
     case Node::Kind::AsyncFunctionPointer:
     case Node::Kind::AsyncAwaitResumePartialFunction:
     case Node::Kind::AsyncSuspendResumePartialFunction:
+    case Node::Kind::AccessibleFunctionRecord:
       return true;
     default:
       return false;
@@ -799,7 +801,7 @@ NodePointer Demangler::demangleOperator() {
         return createWithChild(
             Node::Kind::ProtocolConformanceRefInProtocolModule, popProtocol());
 
-      // Runtime records (type/protocol/conformance)
+      // Runtime records (type/protocol/conformance/function)
       case 'c':
         return createWithChild(Node::Kind::ProtocolConformanceDescriptorRecord,
                                popProtocolConformance());
@@ -809,6 +811,8 @@ NodePointer Demangler::demangleOperator() {
         return createWithChild(Node::Kind::OpaqueTypeDescriptorRecord, popNode());
       case 'r':
         return createWithChild(Node::Kind::ProtocolDescriptorRecord, popProtocol());
+      case 'F':
+        return createNode(Node::Kind::AccessibleFunctionRecord);
 
       default:
         pushBack();
@@ -2363,6 +2367,7 @@ NodePointer Demangler::demangleThunkOrSpecialization() {
     case 'D': return createNode(Node::Kind::DynamicAttribute);
     case 'd': return createNode(Node::Kind::DirectMethodReferenceAttribute);
     case 'E': return createNode(Node::Kind::DistributedThunk);
+    case 'F': return createNode(Node::Kind::DistributedMethodAccessor);
     case 'a': return createNode(Node::Kind::PartialApplyObjCForwarder);
     case 'A': return createNode(Node::Kind::PartialApplyForwarder);
     case 'm': return createNode(Node::Kind::MergedFunction);

lib/Demangling/NodePrinter.cpp

@@ -559,6 +559,7 @@ class NodePrinter {
     case Node::Kind::ProtocolConformanceRefInProtocolModule:
     case Node::Kind::ProtocolConformanceRefInOtherModule:
     case Node::Kind::DistributedThunk:
+    case Node::Kind::DistributedMethodAccessor:
     case Node::Kind::DynamicallyReplaceableFunctionKey:
     case Node::Kind::DynamicallyReplaceableFunctionImpl:
     case Node::Kind::DynamicallyReplaceableFunctionVar:
@@ -585,6 +586,7 @@ class NodePrinter {
     case Node::Kind::IndexSubset:
     case Node::Kind::AsyncAwaitResumePartialFunction:
     case Node::Kind::AsyncSuspendResumePartialFunction:
+    case Node::Kind::AccessibleFunctionRecord:
       return false;
     }
     printer_unreachable("bad node kind");
@@ -1997,6 +1999,16 @@ NodePointer NodePrinter::print(NodePointer Node, unsigned depth,
       Printer << "distributed thunk for ";
     }
     return nullptr;
+  case Node::Kind::DistributedMethodAccessor:
+    if (!Options.ShortenThunk) {
+      Printer << "distributed method accessor for ";
+    }
+    return nullptr;
+  case Node::Kind::AccessibleFunctionRecord:
+    if (!Options.ShortenThunk) {
+      Printer << "accessible function runtime record for ";
+    }
+    return nullptr;
   case Node::Kind::DynamicallyReplaceableFunctionKey:
     if (!Options.ShortenThunk) {
       Printer << "dynamically replaceable key for ";