[NFC] AST: Add StorageImpl.cpp.

And move a couple of StorageImplInfo member functions into it. In
preparation for making them use an ASTContext, to avoid importing that
header into StorageImpl.h, a lightweight header.

Author: nate-chandler

include/swift/AST/StorageImpl.h

@@ -19,6 +19,12 @@
 #define SWIFT_STORAGEIMPL_H
 
 #include "swift/Basic/Range.h"
+#include "llvm/ADT/StringRef.h"
+
+namespace llvm {
+class StringRef;
+class raw_ostream;
+} // namespace llvm
 
 namespace swift {
 
@@ -108,7 +114,7 @@ static inline IntRange<AccessorKind> allAccessorKinds() {
 }
 
 /// \returns a user-readable string name for the accessor kind
-static inline StringRef accessorKindName(AccessorKind ak) {
+static inline llvm::StringRef accessorKindName(AccessorKind ak) {
   switch(ak) {
 
 #define ACCESSOR(ID) ID
@@ -400,10 +406,7 @@ class StorageImplInfo {
   }
 
   /// Describe the implementation of a mutable property implemented opaquely.
-  static StorageImplInfo getMutableOpaque(OpaqueReadOwnership ownership) {
-    return { getOpaqueReadImpl(ownership), WriteImplKind::Set,
-             ReadWriteImplKind::Modify };
-  }
+  static StorageImplInfo getMutableOpaque(OpaqueReadOwnership ownership);
 
   static StorageImplInfo getComputed(StorageIsMutable_t isMutable) {
     return (isMutable ? getMutableComputed()
@@ -451,19 +454,10 @@ class StorageImplInfo {
   }
 
 private:
-  static ReadImplKind getOpaqueReadImpl(OpaqueReadOwnership ownership) {
-    switch (ownership) {
-    case OpaqueReadOwnership::Owned:
-      return ReadImplKind::Get;
-    case OpaqueReadOwnership::OwnedOrBorrowed:
-    case OpaqueReadOwnership::Borrowed:
-      return ReadImplKind::Read;
-    }
-    llvm_unreachable("bad read-ownership kind");
-  }
+  static ReadImplKind getOpaqueReadImpl(OpaqueReadOwnership ownership);
 };
 
-StringRef getAccessorLabel(AccessorKind kind);
+llvm::StringRef getAccessorLabel(AccessorKind kind);
 void simple_display(llvm::raw_ostream &out, AccessorKind kind);
 
 } // end namespace swift

lib/AST/CMakeLists.txt

@@ -117,6 +117,7 @@ add_swift_host_library(swiftAST STATIC
   SearchPathOptions.cpp
   SILLayout.cpp
   Stmt.cpp
+  StorageImpl.cpp
   SubstitutionMap.cpp
   SwiftNameTranslation.cpp
   Type.cpp

lib/AST/StorageImpl.cpp

@@ -0,0 +1,37 @@
+//===--- StorageImpl.cpp - Storage declaration access impl ------*- C++ -*-===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2024 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
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines types for describing the implementation of an
+// AbstractStorageDecl.
+//
+//===----------------------------------------------------------------------===//
+
+#include "swift/AST/StorageImpl.h"
+
+using namespace swift;
+
+StorageImplInfo
+StorageImplInfo::getMutableOpaque(OpaqueReadOwnership ownership) {
+  return {getOpaqueReadImpl(ownership), WriteImplKind::Set,
+          ReadWriteImplKind::Modify};
+}
+
+ReadImplKind StorageImplInfo::getOpaqueReadImpl(OpaqueReadOwnership ownership) {
+  switch (ownership) {
+  case OpaqueReadOwnership::Owned:
+    return ReadImplKind::Get;
+  case OpaqueReadOwnership::OwnedOrBorrowed:
+  case OpaqueReadOwnership::Borrowed:
+    return ReadImplKind::Read;
+  }
+  llvm_unreachable("bad read-ownership kind");
+}