[AST] InitAccessors: Introduce new @storageRestrictions(initializes:accesses:) attribute

This is the replacement for `initializes`, `accesses` attributes.

Author: xedin

include/swift/AST/Attr.h

@@ -1617,6 +1617,45 @@ class AccessesAttr final
   }
 };
 
+class StorageRestrictionsAttr final
+    : public DeclAttribute,
+      private llvm::TrailingObjects<StorageRestrictionsAttr, Identifier> {
+  friend TrailingObjects;
+
+  size_t NumInitializes;
+  size_t NumAccesses;
+
+  size_t numTrailingObjects(OverloadToken<Identifier>) const {
+    return NumInitializes + NumAccesses;
+  }
+
+public:
+  StorageRestrictionsAttr(SourceLoc AtLoc, SourceRange Range,
+                          ArrayRef<Identifier> initializes,
+                          ArrayRef<Identifier> accesses, bool Implicit);
+
+  unsigned getNumInitializesProperties() const { return NumInitializes; }
+
+  unsigned getNumAccessesProperties() const { return NumAccesses; }
+
+  ArrayRef<Identifier> getInitializesNames() const {
+    return {getTrailingObjects<Identifier>(), NumInitializes};
+  }
+
+  ArrayRef<Identifier> getAccessesNames() const {
+    return {getTrailingObjects<Identifier>() + NumInitializes, NumAccesses};
+  }
+
+  static StorageRestrictionsAttr *create(ASTContext &ctx, SourceLoc atLoc,
+                                         SourceRange range,
+                                         ArrayRef<Identifier> initializes,
+                                         ArrayRef<Identifier> accesses);
+
+  static bool classof(const DeclAttribute *DA) {
+    return DA->getKind() == DAK_StorageRestrictions;
+  }
+};
+
 /// The @_implements attribute, which treats a decl as the implementation for
 /// some named protocol requirement (but otherwise not-visible by that name).
 class ImplementsAttr : public DeclAttribute {

lib/AST/Attr.cpp

@@ -1600,6 +1600,8 @@ StringRef DeclAttribute::getAttrName() const {
     return "initializes";
   case DAK_Accesses:
     return "accesses";
+  case DAK_StorageRestrictions:
+    return "storageRestrictions";
   case DAK_Implements:
     return "_implements";
   case DAK_ClangImporterSynthesizedType:
@@ -2405,6 +2407,29 @@ AccessesAttr::create(ASTContext &ctx, SourceLoc atLoc, SourceRange range,
   return new (mem) AccessesAttr(atLoc, range, properties);
 }
 
+StorageRestrictionsAttr::StorageRestrictionsAttr(
+    SourceLoc AtLoc, SourceRange Range, ArrayRef<Identifier> initializes,
+    ArrayRef<Identifier> accesses, bool Implicit)
+    : DeclAttribute(DAK_StorageRestrictions, AtLoc, Range, Implicit),
+      NumInitializes(initializes.size()),
+      NumAccesses(accesses.size()) {
+  std::uninitialized_copy(initializes.begin(), initializes.end(),
+                          getTrailingObjects<Identifier>());
+  std::uninitialized_copy(accesses.begin(), accesses.end(),
+                          getTrailingObjects<Identifier>() + NumInitializes);
+}
+
+StorageRestrictionsAttr *
+StorageRestrictionsAttr::create(
+    ASTContext &ctx, SourceLoc atLoc, SourceRange range,
+    ArrayRef<Identifier> initializes, ArrayRef<Identifier> accesses) {
+  unsigned size =
+      totalSizeToAlloc<Identifier>(initializes.size() + accesses.size());
+  void *mem = ctx.Allocate(size, alignof(StorageRestrictionsAttr));
+  return new (mem) StorageRestrictionsAttr(atLoc, range, initializes, accesses,
+                                           /*implicit=*/false);
+}
+
 ImplementsAttr::ImplementsAttr(SourceLoc atLoc, SourceRange range,
                                TypeRepr *TyR,
                                DeclName MemberName,

lib/Parse/ParseDecl.cpp

@@ -3424,6 +3424,10 @@ ParserStatus Parser::parseNewDeclAttribute(DeclAttributes &Attributes,
     llvm_unreachable("AccessesAttr not yet implemented");
   }
 
+  case DAK_StorageRestrictions: {
+    llvm_unreachable("StorageRestrictionsAttr not yet implemented");
+  }
+
   case DAK_Implements: {
     ParserResult<ImplementsAttr> Attr = parseImplementsAttribute(AtLoc, Loc);
     if (Attr.isNonNull()) {

lib/Sema/TypeCheckAttr.cpp

@@ -296,6 +296,7 @@ class AttributeChecker : public AttributeVisitor<AttributeChecker> {
   void visitTypeEraserAttr(TypeEraserAttr *attr);
   void visitInitializesAttr(InitializesAttr *attr);
   void visitAccessesAttr(AccessesAttr *attr);
+  void visitStorageRestrictionsAttr(StorageRestrictionsAttr *attr);
   void visitImplementsAttr(ImplementsAttr *attr);
   void visitNoMetadataAttr(NoMetadataAttr *attr);
 
@@ -3589,6 +3590,9 @@ void AttributeChecker::visitAccessesAttr(AccessesAttr *attr) {
   }
 }
 
+void AttributeChecker::visitStorageRestrictionsAttr(StorageRestrictionsAttr *attr) {
+}
+
 void AttributeChecker::visitImplementsAttr(ImplementsAttr *attr) {
   DeclContext *DC = D->getDeclContext();
 

lib/Sema/TypeCheckDeclOverride.cpp

@@ -1583,6 +1583,7 @@ namespace  {
     UNINTERESTING_ATTR(RestatedObjCConformance)
     UNINTERESTING_ATTR(Initializes)
     UNINTERESTING_ATTR(Accesses)
+    UNINTERESTING_ATTR(StorageRestrictions)
     UNINTERESTING_ATTR(Implements)
     UNINTERESTING_ATTR(StaticInitializeObjCMetadata)
     UNINTERESTING_ATTR(ClangImporterSynthesizedType)

utils/gyb_syntax_support/AttributeKinds.py

@@ -946,6 +946,11 @@ def __init__(self, name, swift_name=None):
                   code=142),
     DeclAttributeAlias('freestanding', 'MacroRole'),
 
+    DeclAttribute('storageRestrictions', 'StorageRestrictions',
+                  OnAccessor,
+                  ABIStableToAdd, ABIStableToRemove,
+                  APIBreakingToAdd, APIBreakingToRemove,
+                  code=145),
 ]
 
 DEPRECATED_MODIFIER_KINDS = [