Merge pull request #67107 from xedin/setterless-init-accessor-properties

[SILGen/DI] Add support for init accessor properties without setters

Author: xedin

include/swift/SIL/SILInstruction.h

@@ -4873,6 +4873,7 @@ class AssignOrInitInst
   ArrayRef<Operand> getAllOperands() const { return Operands.asArray(); }
   MutableArrayRef<Operand> getAllOperands() { return Operands.asArray(); }
 
+  StringRef getPropertyName() const;
   AccessorDecl *getReferencedInitAccessor() const;
 };
 

lib/AST/Decl.cpp

@@ -2413,10 +2413,15 @@ getDirectReadAccessStrategy(const AbstractStorageDecl *storage) {
 static AccessStrategy
 getDirectWriteAccessStrategy(const AbstractStorageDecl *storage) {
   switch (storage->getWriteImpl()) {
-  case WriteImplKind::Immutable:
+  case WriteImplKind::Immutable: {
+    if (storage->hasInitAccessor())
+      return AccessStrategy::getAccessor(AccessorKind::Init,
+                                         /*dispatch=*/false);
+
     assert(isa<VarDecl>(storage) && cast<VarDecl>(storage)->isLet() &&
            "mutation of a immutable variable that isn't a let");
     return AccessStrategy::getStorage();
+  }
   case WriteImplKind::Stored:
     return AccessStrategy::getStorage();
   case WriteImplKind::StoredWithObservers:
@@ -2493,7 +2498,9 @@ getOpaqueReadAccessStrategy(const AbstractStorageDecl *storage, bool dispatch) {
 }
 
 static AccessStrategy
-getOpaqueWriteAccessStrategy(const AbstractStorageDecl *storage, bool dispatch){
+getOpaqueWriteAccessStrategy(const AbstractStorageDecl *storage, bool dispatch) {
+  if (storage->hasInitAccessor() && !storage->getAccessor(AccessorKind::Set))
+    return AccessStrategy::getAccessor(AccessorKind::Init, dispatch);
   return AccessStrategy::getAccessor(AccessorKind::Set, dispatch);
 }
 
@@ -6827,8 +6834,17 @@ bool VarDecl::isSettable(const DeclContext *UseDC,
 
   // If this is a 'var' decl, then we're settable if we have storage or a
   // setter.
-  if (!isLet())
+  if (!isLet()) {
+    if (hasInitAccessor()) {
+      if (auto *ctor = dyn_cast_or_null<ConstructorDecl>(UseDC)) {
+        if (base && ctor->getImplicitSelfDecl() != base->getDecl())
+          return supportsMutation();
+        return true;
+      }
+    }
+
     return supportsMutation();
+  }
 
   // Static 'let's are always immutable.
   if (isStatic()) {

lib/SIL/IR/SILInstructions.cpp

@@ -1290,6 +1290,12 @@ bool AssignOrInitInst::isPropertyAlreadyInitialized(unsigned propertyIdx) {
   return Assignments.test(propertyIdx);
 }
 
+StringRef AssignOrInitInst::getPropertyName() const {
+  auto *accessor = getReferencedInitAccessor();
+  assert(accessor);
+  return cast<VarDecl>(accessor->getStorage())->getNameStr();
+}
+
 AccessorDecl *AssignOrInitInst::getReferencedInitAccessor() const {
   SILValue initRef = getInitializer();
   SILFunction *accessorFn = nullptr;

lib/SIL/Verifier/SILVerifier.cpp

@@ -2736,6 +2736,9 @@ class SILVerifier : public SILVerifierBase<SILVerifier> {
       checkAssigOrInitInstAccessorArgs(Src->getType(), initConv);
     }
 
+    if (isa<SILUndef>(setterFn))
+      return;
+
     // Check setter - it's a partially applied reference which takes
     // `initialValue`.
     CanSILFunctionType setterTy = setterFn->getType().castTo<SILFunctionType>();

lib/SILGen/LValue.h

@@ -115,6 +115,7 @@ class PathComponent {
     WritebackPseudoKind,        // a fake component to customize writeback
     OpenNonOpaqueExistentialKind,  // opened class or metatype existential
     LogicalKeyPathApplicationKind, // applying a key path
+    InitAccessorKind,           // init accessor
 
     // Translation LValue kinds (a subtype of logical)
     OrigToSubstKind,            // generic type substitution