[Mangling] Separate out base conformance descriptors.

DougGregor · DougGregor · commit 46ece0a9b492 · 2018-12-04T16:15:58.000-08:00
Separate the mangling of base conformance descriptors from that of associated conformance descriptors, and simplify it. (cherry picked from commit e6620b0)
diff --git a/docs/ABI/Mangling.rst b/docs/ABI/Mangling.rst
@@ -200,8 +200,8 @@ types where the metadata itself has unknown layout.)
   global ::= assoc-type-name 'Tl'        // associated type descriptor
   global ::= assoc-type-name 'TM'        // default associated type witness accessor (HISTORICAL)
   global ::= type assoc-type-list protocol 'Tn' // associated conformance descriptor
-  global ::= type type protocol 'Tn' // inherited protocol witness descriptor
   global ::= type assoc-type-list protocol 'TN' // default associated conformance witness accessor
+  global ::= type protocol 'Tb'          // base conformance descriptor
 
   REABSTRACT-THUNK-TYPE ::= 'R'          // reabstraction thunk helper function
   REABSTRACT-THUNK-TYPE ::= 'r'          // reabstraction thunk
diff --git a/include/swift/AST/ProtocolAssociations.h b/include/swift/AST/ProtocolAssociations.h
@@ -68,6 +68,27 @@ class AssociatedType {
   }
 };
 
+/// A base conformance of a protocol.
+class BaseConformance {
+  ProtocolDecl *Source;
+  ProtocolDecl *Requirement;
+
+public:
+  explicit BaseConformance(ProtocolDecl *source,
+                                 ProtocolDecl *requirement)
+      : Source(source), Requirement(requirement) {
+    assert(source && requirement);
+  }
+
+  ProtocolDecl *getSourceProtocol() const {
+    return Source;
+  }
+
+  ProtocolDecl *getBaseRequirement() const {
+    return Requirement;
+  }
+};
+
 /// A conformance associated with a protocol.
 class AssociatedConformance {
   ProtocolDecl *Source;
diff --git a/include/swift/Demangling/DemangleNodes.def b/include/swift/Demangling/DemangleNodes.def
@@ -226,6 +226,7 @@ NODE(MethodDescriptor)
 NODE(ProtocolRequirementsBaseDescriptor)
 NODE(AssociatedConformanceDescriptor)
 NODE(DefaultAssociatedConformanceAccessor)
+NODE(BaseConformanceDescriptor)
 NODE(AssociatedTypeDescriptor)
 NODE(ThrowsAnnotation)
 NODE(EmptyList)
diff --git a/include/swift/IRGen/Linking.h b/include/swift/IRGen/Linking.h
@@ -230,6 +230,13 @@ class LinkEntity {
     /// is stored in the data.
     DefaultAssociatedConformanceAccessor,
 
+    /// An descriptor for an base conformance within a protocol, which
+    /// will alias the TargetProtocolRequirement descripting this
+    /// particular base conformance.
+    /// The pointer is a ProtocolDecl*; the index of the base conformance
+    /// is stored in the data.
+    BaseConformanceDescriptor,
+
     /// A global function pointer for dynamically replaceable functions.
     /// The pointer is a AbstractStorageDecl*.
     DynamicallyReplaceableFunctionVariableAST,
@@ -810,6 +817,18 @@ class LinkEntity {
     return entity;
   }
 
+  static LinkEntity
+  forBaseConformanceDescriptor(BaseConformance conformance) {
+    LinkEntity entity;
+    entity.setForProtocolAndAssociatedConformance(
+        Kind::BaseConformanceDescriptor,
+        conformance.getSourceProtocol(),
+        conformance.getSourceProtocol()->getSelfInterfaceType()
+          ->getCanonicalType(),
+        conformance.getBaseRequirement());
+    return entity;
+  }
+
   static LinkEntity
   forAssociatedTypeWitnessTableAccessFunction(const ProtocolConformance *C,
                                      const AssociatedConformance &association) {
@@ -963,7 +982,8 @@ class LinkEntity {
     }
 
     assert(getKind() == Kind::AssociatedConformanceDescriptor ||
-           getKind() == Kind::DefaultAssociatedConformanceAccessor);
+           getKind() == Kind::DefaultAssociatedConformanceAccessor ||
+           getKind() == Kind::BaseConformanceDescriptor);
     return getAssociatedConformanceByIndex(
              cast<ProtocolDecl>(getDecl()),
              LINKENTITY_GET_FIELD(Data, AssociatedConformanceIndex));
diff --git a/lib/Demangling/Demangler.cpp b/lib/Demangling/Demangler.cpp
@@ -2055,21 +2055,28 @@ NodePointer Demangler::demangleThunkOrSpecialization() {
 
     case 'n': {
       NodePointer requirementTy = popProtocol();
-      NodePointer conformingType = popSelfOrAssocTypePath();
+      NodePointer conformingType = popAssocTypePath();
       NodePointer protoTy = popNode(Node::Kind::Type);
       return createWithChildren(Node::Kind::AssociatedConformanceDescriptor,
                                 protoTy, conformingType, requirementTy);
     }
 
     case 'N': {
       NodePointer requirementTy = popProtocol();
-      auto assocTypePath = popSelfOrAssocTypePath();
+      auto assocTypePath = popAssocTypePath();
       NodePointer protoTy = popNode(Node::Kind::Type);
       return createWithChildren(
                             Node::Kind::DefaultAssociatedConformanceAccessor,
                             protoTy, assocTypePath, requirementTy);
     }
 
+    case 'b': {
+      NodePointer requirementTy = popProtocol();
+      NodePointer protoTy = popNode(Node::Kind::Type);
+      return createWithChildren(Node::Kind::BaseConformanceDescriptor,
+                                protoTy, requirementTy);
+    }
+
     case 'H':
     case 'h': {
       auto nodeKind = c == 'H' ? Node::Kind::KeyPathEqualsThunkHelper
diff --git a/lib/Demangling/NodePrinter.cpp b/lib/Demangling/NodePrinter.cpp
@@ -319,6 +319,7 @@ class NodePrinter {
     case Node::Kind::AssociatedTypeMetadataAccessor:
     case Node::Kind::AssociatedTypeWitnessTableAccessor:
     case Node::Kind::AutoClosureType:
+    case Node::Kind::BaseConformanceDescriptor:
     case Node::Kind::ClassMetadataBaseOffset:
     case Node::Kind::CFunctionPointer:
     case Node::Kind::Constructor:
@@ -1637,6 +1638,12 @@ NodePointer NodePrinter::print(NodePointer Node, bool asPrefixContext) {
     Printer << " in ";
     print(Node->getChild(0));
     return nullptr;
+  case Node::Kind::BaseConformanceDescriptor:
+    Printer << "base conformance descriptor for ";
+    print(Node->getChild(0));
+    Printer << ": ";
+    print(Node->getChild(1));
+    return nullptr;
   case Node::Kind::DefaultAssociatedTypeMetadataAccessor:
     Printer << "default associated type metadata accessor for ";
     print(Node->getChild(0));
diff --git a/lib/Demangling/OldRemangler.cpp b/lib/Demangling/OldRemangler.cpp
@@ -942,6 +942,10 @@ void Remangler::mangleDefaultAssociatedConformanceAccessor(Node *node) {
   Out << "<default-associated-conformance-descriptor>";
 }
 
+void Remangler::mangleBaseConformanceDescriptor(Node *node) {
+  Out << "<base-conformance-descriptor>";
+}
+
 void Remangler::mangleAssociatedTypeMetadataAccessor(Node *node) {
   Out << "Wt";
   mangleChildNodes(node); // protocol conformance, identifier
diff --git a/lib/Demangling/Remangler.cpp b/lib/Demangling/Remangler.cpp
@@ -585,6 +585,11 @@ void Remangler::mangleDefaultAssociatedConformanceAccessor(Node *node) {
   Buffer << "TN";
 }
 
+void Remangler::mangleBaseConformanceDescriptor(Node *node) {
+  mangleChildNodes(node);
+  Buffer << "Tb";
+}
+
 void Remangler::mangleAssociatedTypeMetadataAccessor(Node *node) {
   mangleChildNodes(node); // protocol conformance, identifier
   Buffer << "Wt";
diff --git a/lib/IRGen/GenDecl.cpp b/lib/IRGen/GenDecl.cpp
@@ -3536,6 +3536,19 @@ llvm::GlobalValue *IRGenModule::defineAssociatedConformanceDescriptor(
   return defineAlias(entity, definition);
 }
 
+llvm::Constant *IRGenModule::getAddrOfBaseConformanceDescriptor(
+                                                BaseConformance conformance) {
+  auto entity = LinkEntity::forBaseConformanceDescriptor(conformance);
+  return getAddrOfLLVMVariable(entity, ConstantInit(), DebugTypeInfo());
+}
+
+llvm::GlobalValue *IRGenModule::defineBaseConformanceDescriptor(
+                                            BaseConformance conformance,
+                                            llvm::Constant *definition) {
+  auto entity = LinkEntity::forBaseConformanceDescriptor(conformance);
+  return defineAlias(entity, definition);
+}
+
 llvm::Constant *IRGenModule::getAddrOfProtocolConformanceDescriptor(
                                 const RootProtocolConformance *conformance,
                                 ConstantInit definition) {
diff --git a/lib/IRGen/GenMeta.cpp b/lib/IRGen/GenMeta.cpp
@@ -730,15 +730,10 @@ namespace {
         }
 
         if (entry.isBase()) {
-          // Define the associated conformance descriptor to point to the
-          // current position in the protocol descriptor, which is an
-          // out-of-line base protocol.
-          AssociatedConformance conformance(
-                                  Proto,
-                                  Proto->getProtocolSelfType()
-                                    ->getCanonicalType(),
-                                  entry.getBase());
-          IGM.defineAssociatedConformanceDescriptor(
+          // Define a base conformance descriptor, which is just an associated
+          // conformance descriptor for a base protocol.
+          BaseConformance conformance(Proto, entry.getBase());
+          IGM.defineBaseConformanceDescriptor(
               conformance,
               B.getAddrOfCurrentPosition(IGM.ProtocolRequirementStructTy));
         }
diff --git a/lib/IRGen/GenProto.cpp b/lib/IRGen/GenProto.cpp
@@ -1994,13 +1994,10 @@ namespace {
           // Associated conformance descriptor for a base protocol.
           const auto &witness = entry.getBaseProtocolWitness();
           auto proto = SILWT->getProtocol();
-          AssociatedConformance requirement(proto,
-                                            proto->getSelfInterfaceType()
-                                              ->getCanonicalType(),
-                                            witness.Requirement);
+          BaseConformance requirement(proto, witness.Requirement);
           auto baseConformanceDescriptor =
             IGM.getAddrOfLLVMVariableOrGOTEquivalent(
-              LinkEntity::forAssociatedConformanceDescriptor(requirement));
+              LinkEntity::forBaseConformanceDescriptor(requirement));
           B.addRelativeAddress(baseConformanceDescriptor);
         } else if (entry.getKind() == SILWitnessTable::Method) {
           // Method descriptor.
diff --git a/lib/IRGen/IRGenMangler.h b/lib/IRGen/IRGenMangler.h
@@ -208,6 +208,16 @@ class IRGenMangler : public Mangle::ASTMangler {
     return finalize();
   }
 
+  std::string mangleBaseConformanceDescriptor(
+      const ProtocolDecl *proto,
+      const ProtocolDecl *requirement) {
+    beginMangling();
+    appendAnyGenericType(proto);
+    appendProtocolName(requirement);
+    appendOperator("Tb");
+    return finalize();
+  }
+
   std::string mangleDefaultAssociatedConformanceAccessor(
       const ProtocolDecl *proto,
       CanType subject,
diff --git a/lib/IRGen/IRGenModule.h b/lib/IRGen/IRGenModule.h
@@ -82,6 +82,7 @@ namespace swift {
   class AssociatedConformance;
   class AssociatedType;
   class ASTContext;
+  class BaseConformance;
   class BraceStmt;
   class CanType;
   class LinkLibrary;
@@ -1296,6 +1297,11 @@ private:                            \
   llvm::GlobalValue *defineAssociatedConformanceDescriptor(
                                               AssociatedConformance conformance,
                                               llvm::Constant *definition);
+  llvm::Constant *getAddrOfBaseConformanceDescriptor(
+                                                 BaseConformance conformance);
+  llvm::GlobalValue *defineBaseConformanceDescriptor(
+                                              BaseConformance conformance,
+                                              llvm::Constant *definition);
 
   llvm::Constant *getAddrOfProtocolDescriptor(ProtocolDecl *D,
                                       ConstantInit definition = ConstantInit());
diff --git a/lib/IRGen/Linking.cpp b/lib/IRGen/Linking.cpp
@@ -202,6 +202,13 @@ std::string LinkEntity::mangleAsString() const {
              assocConformance.second);
   }
 
+  case Kind::BaseConformanceDescriptor: {
+    auto assocConformance = getAssociatedConformance();
+    return mangler.mangleBaseConformanceDescriptor(
+             cast<ProtocolDecl>(getDecl()),
+             assocConformance.second);
+  }
+
   case Kind::DefaultAssociatedConformanceAccessor: {
     auto assocConformance = getAssociatedConformance();
     return mangler.mangleDefaultAssociatedConformanceAccessor(
@@ -505,6 +512,7 @@ SILLinkage LinkEntity::getLinkage(ForDefinition_t forDefinition) const {
   }
 
   case Kind::AssociatedConformanceDescriptor:
+  case Kind::BaseConformanceDescriptor:
   case Kind::ObjCClass:
   case Kind::ObjCMetaclass:
   case Kind::SwiftMetaclassStub:
@@ -656,6 +664,7 @@ bool LinkEntity::isAvailableExternally(IRGenModule &IGM) const {
     return true;
 
   case Kind::AssociatedConformanceDescriptor:
+  case Kind::BaseConformanceDescriptor:
   case Kind::SwiftMetaclassStub:
   case Kind::ClassMetadataBaseOffset:
   case Kind::PropertyDescriptor:
@@ -737,6 +746,7 @@ llvm::Type *LinkEntity::getDefaultDeclarationType(IRGenModule &IGM) const {
     return IGM.ProtocolDescriptorStructTy;
   case Kind::AssociatedTypeDescriptor:
   case Kind::AssociatedConformanceDescriptor:
+  case Kind::BaseConformanceDescriptor:
   case Kind::ProtocolRequirementsBaseDescriptor:
     return IGM.ProtocolRequirementStructTy;
   case Kind::ProtocolConformanceDescriptor:
@@ -818,6 +828,7 @@ Alignment LinkEntity::getAlignment(IRGenModule &IGM) const {
   case Kind::ProtocolDescriptor:
   case Kind::AssociatedTypeDescriptor:
   case Kind::AssociatedConformanceDescriptor:
+  case Kind::BaseConformanceDescriptor:
   case Kind::ProtocolConformanceDescriptor:
   case Kind::ProtocolRequirementsBaseDescriptor:
   case Kind::ReflectionBuiltinDescriptor:
@@ -880,11 +891,12 @@ bool LinkEntity::isWeakImported(ModuleDecl *module) const {
     // their declaration, but are weak linked if the associated
     // type stored in extra storage area is weak linked.
     auto assocConformance = getAssociatedConformance();
-    if (auto *depMemTy = assocConformance.first->getAs<DependentMemberType>())
-      return depMemTy->getAssocType()->isWeakImported(module);
+    auto *depMemTy = assocConformance.first->castTo<DependentMemberType>();
+    return depMemTy->getAssocType()->isWeakImported(module);
+  }
 
+  case Kind::BaseConformanceDescriptor:
     return cast<ProtocolDecl>(getDecl())->isWeakImported(module);
-  }
 
   case Kind::TypeMetadata:
   case Kind::TypeMetadataAccessFunction: {
@@ -989,6 +1001,7 @@ const SourceFile *LinkEntity::getSourceFileForEmission() const {
   case Kind::AssociatedTypeDescriptor:
   case Kind::AssociatedConformanceDescriptor:
   case Kind::DefaultAssociatedConformanceAccessor:
+  case Kind::BaseConformanceDescriptor:
   case Kind::DynamicallyReplaceableFunctionVariableAST:
   case Kind::DynamicallyReplaceableFunctionKeyAST:
   case Kind::DynamicallyReplaceableFunctionImpl:
diff --git a/lib/TBDGen/TBDGen.cpp b/lib/TBDGen/TBDGen.cpp
@@ -105,6 +105,12 @@ void TBDGenVisitor::addAssociatedConformanceDescriptor(
   addSymbol(entity);
 }
 
+void TBDGenVisitor::addBaseConformanceDescriptor(
+                                           BaseConformance conformance) {
+  auto entity = LinkEntity::forBaseConformanceDescriptor(conformance);
+  addSymbol(entity);
+}
+
 void TBDGenVisitor::addConformances(DeclContext *DC) {
   for (auto conformance : DC->getLocalConformances()) {
     auto protocol = conformance->getProtocol();
@@ -432,11 +438,18 @@ void TBDGenVisitor::visitProtocolDecl(ProtocolDecl *PD) {
       if (req.getKind() != RequirementKind::Conformance)
         continue;
 
-      AssociatedConformance conformance(
-        PD,
-        req.getFirstType()->getCanonicalType(),
-        req.getSecondType()->castTo<ProtocolType>()->getDecl());
-      addAssociatedConformanceDescriptor(conformance);
+      if (req.getFirstType()->isEqual(PD->getSelfInterfaceType())) {
+        BaseConformance conformance(
+          PD,
+          req.getSecondType()->castTo<ProtocolType>()->getDecl());
+        addBaseConformanceDescriptor(conformance);
+      } else {
+        AssociatedConformance conformance(
+          PD,
+          req.getFirstType()->getCanonicalType(),
+          req.getSecondType()->castTo<ProtocolType>()->getDecl());
+        addAssociatedConformanceDescriptor(conformance);
+      }
     }
 
     for (auto *member : PD->getMembers()) {
diff --git a/lib/TBDGen/TBDGenVisitor.h b/lib/TBDGen/TBDGenVisitor.h
@@ -67,6 +67,7 @@ class TBDGenVisitor : public ASTVisitor<TBDGenVisitor> {
   void addProtocolRequirementsBaseDescriptor(ProtocolDecl *proto);
   void addAssociatedTypeDescriptor(AssociatedTypeDecl *assocType);
   void addAssociatedConformanceDescriptor(AssociatedConformance conformance);
+  void addBaseConformanceDescriptor(BaseConformance conformance);
 
 public:
   TBDGenVisitor(tapi::internal::InterfaceFile &symbols,
diff --git a/test/IRGen/protocol_resilience_descriptors.swift b/test/IRGen/protocol_resilience_descriptors.swift
@@ -30,7 +30,7 @@
 // CHECK-DEFINITION: @"$s18resilient_protocol21ResilientBaseProtocolTL" ={{( dllexport)?}}{{( protected)?}} alias %swift.protocol_requirement, getelementptr (%swift.protocol_requirement, %swift.protocol_requirement* getelementptr inbounds (<{ i32, i32, i32, i32, i32, i32, %swift.protocol_requirement }>, <{ i32, i32, i32, i32, i32, i32, %swift.protocol_requirement }>* @"$s18resilient_protocol21ResilientBaseProtocolMp", i32 0, i32 6), i32 -1)
 
 // Associated conformance descriptor for inherited protocol
-// CHECK-DEFINITION-LABEL: s18resilient_protocol24ResilientDerivedProtocolPxAA0c4BaseE0Tn" ={{( dllexport)?}}{{( protected)?}} alias
+// CHECK-DEFINITION-LABEL: s18resilient_protocol24ResilientDerivedProtocolPAA0c4BaseE0Tb" ={{( dllexport)?}}{{( protected)?}} alias
 
 // Associated type and conformance
 
