Merge pull request #15208 from aschwaighofer/resilient_enum_case_tags

IRGen: Make resilient enum's tag indices resilient

Author: aschwaighofer

docs/ABI/Mangling.rst

@@ -88,6 +88,7 @@ Globals
   global ::= type protocol-conformance 'Wl' // lazy protocol witness table accessor
   global ::= type 'WV'                   // value witness table
   global ::= entity 'Wv' DIRECTNESS      // field offset
+  global ::= entity 'WC' // resilient enum tag index
 
   global ::= type 'Wy' // Outlined Copy Function Type
   global ::= type 'We' // Outlined Consume Function Type

include/swift/ABI/ValueWitness.def

@@ -180,23 +180,23 @@ FUNCTION_VALUE_WITNESS(initializeBufferWithTakeOfBuffer,
                        MUTABLE_VALUE_TYPE,
                        (MUTABLE_BUFFER_TYPE, MUTABLE_BUFFER_TYPE, TYPE_TYPE))
 
-/// int (*getEnumTagSinglePayload)(const T* enum, UINT_TYPE emptyCases)
+/// unsigned (*getEnumTagSinglePayload)(const T* enum, UINT_TYPE emptyCases)
 /// Given an instance of valid single payload enum with a payload of this
 /// witness table's type (e.g Optional<ThisType>) , get the tag of the enum.
 FUNCTION_VALUE_WITNESS(getEnumTagSinglePayload,
                        GetEnumTagSinglePayload,
-                       INT_TYPE,
+                       UINT_TYPE,
                        (IMMUTABLE_VALUE_TYPE, UINT_TYPE, TYPE_TYPE))
 
-/// void (*storeEnumTagSinglePayload)(T* enum, INT_TYPE whichCase,
+/// void (*storeEnumTagSinglePayload)(T* enum, UINT_TYPE whichCase,
 ///                                   UINT_TYPE emptyCases)
 /// Given uninitialized memory for an instance of a single payload enum with a
 /// payload of this witness table's type (e.g Optional<ThisType>), store the
 /// tag.
 FUNCTION_VALUE_WITNESS(storeEnumTagSinglePayload,
                        StoreEnumTagSinglePayload,
                        VOID_TYPE,
-                       (MUTABLE_VALUE_TYPE, INT_TYPE, UINT_TYPE, TYPE_TYPE))
+                       (MUTABLE_VALUE_TYPE, UINT_TYPE, UINT_TYPE, TYPE_TYPE))
 
 END_VALUE_WITNESS_RANGE(RequiredValueWitnessFunction,
                         StoreEnumTagSinglePayload)
@@ -327,11 +327,11 @@ END_VALUE_WITNESS_RANGE(ExtraInhabitantValueWitness,
 // The following value witnesses are conditionally present if the witnessed
 // type is an enum.
 
-///   int (*getEnumTag)(T *obj, M *self);
+///   unsigned (*getEnumTag)(T *obj, M *self);
 ///
 /// Given a valid object of this enum type, extracts the tag value indicating
 /// which case of the enum is inhabited. Returned values are in the range
-/// [-ElementsWithPayload..ElementsWithNoPayload-1].
+/// [0..NumElements-1].
 FUNCTION_VALUE_WITNESS(getEnumTag,
                        GetEnumTag,
                        INT_TYPE,
@@ -348,14 +348,14 @@ FUNCTION_VALUE_WITNESS(destructiveProjectEnumData,
                        VOID_TYPE,
                        (MUTABLE_VALUE_TYPE, TYPE_TYPE))
 
-///   void (*destructiveInjectEnumTag)(T *obj, int tag, M *self);
+///   void (*destructiveInjectEnumTag)(T *obj, unsigned tag, M *self);
 /// Given an enum case tag and a valid object of case's payload type,
 /// destructively inserts the tag into the payload. The given tag value
 /// must be in the range [-ElementsWithPayload..ElementsWithNoPayload-1].
 FUNCTION_VALUE_WITNESS(destructiveInjectEnumTag,
                        DestructiveInjectEnumTag,
                        VOID_TYPE,
-                       (MUTABLE_VALUE_TYPE, INT_TYPE, TYPE_TYPE))
+                       (MUTABLE_VALUE_TYPE, UINT_TYPE, TYPE_TYPE))
 
 END_VALUE_WITNESS_RANGE(EnumValueWitness,
                         DestructiveInjectEnumTag)

include/swift/Demangling/DemangleNodes.def

@@ -62,6 +62,7 @@ NODE(DynamicAttribute)
 NODE(DirectMethodReferenceAttribute)
 NODE(DynamicSelf)
 CONTEXT_NODE(Enum)
+NODE(EnumCase)
 NODE(ErrorType)
 NODE(EscapingAutoClosureType)
 NODE(NoEscapeFunctionType)

include/swift/IRGen/Linking.h

@@ -116,6 +116,9 @@ class LinkEntity {
     /// ConstructorDecl* inside a protocol or a class.
     DispatchThunkAllocator,
 
+    /// A resilient enum tag index. The pointer is a EnumElementDecl*.
+    EnumCase,
+
     /// A field offset.  The pointer is a VarDecl*.
     FieldOffset,
 
@@ -434,6 +437,12 @@ class LinkEntity {
     return entity;
   }
 
+  static LinkEntity forEnumCase(EnumElementDecl *decl) {
+    LinkEntity entity;
+    entity.setForDecl(Kind::EnumCase, decl);
+    return entity;
+  }
+
   static LinkEntity forObjCClassRef(ClassDecl *decl) {
     LinkEntity entity;
     entity.setForDecl(Kind::ObjCClassRef, decl);

include/swift/Runtime/Enum.h

@@ -64,30 +64,29 @@ void swift_initEnumMetadataSinglePayload(EnumMetadata *enumType,
 /// \param payload - type metadata for the payload case of the enum.
 /// \param emptyCases - the number of empty cases in the enum.
 ///
-/// \returns -1 if the payload case is inhabited. If an empty case is inhabited,
-///          returns a value greater than or equal to zero and less than
+/// \returns 0 if the payload case is inhabited. If an empty case is inhabited,
+///          returns a value greater than or equal to one and less than or equal
 ///          emptyCases.
 SWIFT_RUNTIME_EXPORT
-int swift_getEnumCaseSinglePayload(const OpaqueValue *value,
-                                   const Metadata *payload,
-                                   unsigned emptyCases);
-
+unsigned swift_getEnumCaseSinglePayload(const OpaqueValue *value,
+                                        const Metadata *payload,
+                                        unsigned emptyCases);
 
 /// \brief Store the tag value for the given case into a single-payload enum,
 ///        whose associated payload (if any) has already been initialized.
 ///
 /// \param value - pointer to the enum value. If the case being initialized is
-///                the payload case (-1), then the payload should be
+///                the payload case (0), then the payload should be
 ///                initialized.
 /// \param payload - type metadata for the payload case of the enum.
-/// \param whichCase - unique value identifying the case. -1 for the payload
-///                    case, or a value greater than or equal to zero and less
-///                    than emptyCases for an empty case.
+/// \param whichCase - unique value identifying the case. 0 for the payload
+///                    case, or a value greater than or equal to one and less
+///                    than or equal emptyCases for an empty case.
 /// \param emptyCases - the number of empty cases in the enum.
 SWIFT_RUNTIME_EXPORT
 void swift_storeEnumTagSinglePayload(OpaqueValue *value,
                                      const Metadata *payload,
-                                     int whichCase,
+                                     unsigned whichCase,
                                      unsigned emptyCases);
 
 /// \brief Initialize the type metadata for a generic, multi-payload

include/swift/Runtime/Metadata.h

@@ -842,7 +842,7 @@ struct TargetMetadata {
     getValueWitnesses()->_asXIVWT()->storeExtraInhabitant(value, index, this);
   }
 
-  int vw_getEnumTag(const OpaqueValue *value) const {
+  unsigned vw_getEnumTag(const OpaqueValue *value) const {
     return getValueWitnesses()->_asEVWT()->getEnumTag(const_cast<OpaqueValue*>(value), this);
   }
   void vw_destructiveProjectEnumData(OpaqueValue *value) const {

include/swift/Runtime/RuntimeFunctions.def

@@ -987,7 +987,7 @@ FUNCTION(GetEnumCaseMultiPayload,
          ATTRS(NoUnwind, ReadOnly))
 
 // void swift_storeEnumTagSinglePayload(opaque_t *obj, Metadata *payload,
-//                                      int case_index,
+//                                      unsigned case_index,
 //                                      unsigned num_empty_cases);
 FUNCTION(StoreEnumTagSinglePayload,
          swift_storeEnumTagSinglePayload,

lib/Demangling/Demangler.cpp

@@ -2049,6 +2049,9 @@ NodePointer Demangler::demangleSpecAttributes(Node::Kind SpecKind,
 
 NodePointer Demangler::demangleWitness() {
   switch (nextChar()) {
+    case 'C':
+      return createWithChild(Node::Kind::EnumCase,
+                             popNode(isEntity));
     case 'V':
       return createWithChild(Node::Kind::ValueWitnessTable,
                              popNode(Node::Kind::Type));

lib/Demangling/NodePrinter.cpp

@@ -333,6 +333,7 @@ class NodePrinter {
     case Node::Kind::NoEscapeFunctionType:
     case Node::Kind::ExplicitClosure:
     case Node::Kind::Extension:
+    case Node::Kind::EnumCase:
     case Node::Kind::FieldOffset:
     case Node::Kind::FullTypeMetadata:
     case Node::Kind::Function:
@@ -1397,6 +1398,12 @@ NodePointer NodePrinter::print(NodePointer Node, bool asPrefixContext) {
     print(entity, /*asContext*/ false);
     return nullptr;
   }
+  case Node::Kind::EnumCase: {
+    Printer << "enum case for ";
+    auto entity = Node->getChild(0);
+    print(entity, /*asContext*/ false);
+    return nullptr;
+  }
   case Node::Kind::ReabstractionThunk:
   case Node::Kind::ReabstractionThunkHelper: {
     if (Options.ShortenThunk) {

lib/Demangling/OldRemangler.cpp

@@ -811,6 +811,11 @@ void Remangler::mangleFieldOffset(Node *node) {
   mangleChildNodes(node); // directness, entity
 }
 
+void Remangler::mangleEnumCase(Node *node) {
+  Out << "WC";
+  mangleSingleChildNode(node); // enum case
+}
+
 void Remangler::mangleProtocolWitnessTable(Node *node) {
   Out << "WP";
   mangleSingleChildNode(node); // protocol conformance

lib/Demangling/Remangler.cpp

@@ -884,6 +884,11 @@ void Remangler::mangleFieldOffset(Node *node) {
   mangleChildNode(node, 0); // directness
 }
 
+void Remangler::mangleEnumCase(Node *node) {
+  mangleSingleChildNode(node); // enum case
+  Buffer << "WC";
+}
+
 void Remangler::mangleFullTypeMetadata(Node *node) {
   mangleSingleChildNode(node);
   Buffer << "Mf";

lib/IRGen/GenDecl.cpp

@@ -1521,6 +1521,12 @@ SILLinkage LinkEntity::getLinkage(ForDefinition_t forDefinition) const {
   case Kind::CoroutineContinuationPrototype:
     return SILLinkage::PublicExternal;
 
+
+  case Kind::EnumCase: {
+    auto *elementDecl = cast<EnumElementDecl>(getDecl());
+    return getSILLinkage(getDeclLinkage(elementDecl), forDefinition);
+  }
+
   case Kind::FieldOffset: {
     auto *varDecl = cast<VarDecl>(getDecl());
 
@@ -1644,6 +1650,9 @@ bool LinkEntity::isAvailableExternally(IRGenModule &IGM) const {
   case Kind::ProtocolDescriptor:
     return ::isAvailableExternally(IGM, getDecl());
 
+  case Kind::EnumCase:
+    return ::isAvailableExternally(IGM, getDecl());
+
   case Kind::DirectProtocolWitnessTable:
   case Kind::ProtocolConformanceDescriptor:
     return ::isAvailableExternally(IGM, getProtocolConformance()->getDeclContext());
@@ -3571,6 +3580,13 @@ Address IRGenModule::getAddrOfFieldOffset(VarDecl *var,
                                  forDefinition);
 }
 
+Address IRGenModule::getAddrOfEnumCase(EnumElementDecl *Case,
+                                       ForDefinition_t forDefinition) {
+  LinkEntity entity = LinkEntity::forEnumCase(Case);
+  return getAddrOfSimpleVariable(*this, GlobalVars, entity, Int32Ty,
+                                 getPointerAlignment(), forDefinition);
+}
+
 void IRGenModule::emitNestedTypeDecls(DeclRange members) {
   for (Decl *member : members) {
     switch (member->getKind()) {