Improve the mangling of USRs

docs/ABI.rst

@@ -889,7 +889,7 @@ Entities
   entity-spec ::= decl-name type 'i'                 // subscript ('i'ndex) itself (not the individual accessors)
   entity-spec ::= decl-name type 'v'                 // variable
   entity-spec ::= decl-name type 'f' ACCESSOR
-  entity-spec ::= decl-name type 'fp'                // generic type parameter (not used?)
+  entity-spec ::= decl-name type 'fp'                // generic type parameter
   entity-spec ::= decl-name type 'fo'                // enum element (currently not used)
 
   ACCESSOR ::= 'm'                           // materializeForSet
@@ -958,14 +958,15 @@ Types
 
 ::
 
-  nominal-type ::= substitution
-  nominal-type ::= context decl-name 'C'     // nominal class type
-  nominal-type ::= context decl-name 'O'     // nominal enum type
-  nominal-type ::= context decl-name 'V'     // nominal struct type
-  nominal-type ::= protocol 'P'              // nominal protocol type
+  any-generic-type ::= substitution
+  any-generic-type ::= context decl-name 'C'     // nominal class type
+  any-generic-type ::= context decl-name 'O'     // nominal enum type
+  any-generic-type ::= context decl-name 'V'     // nominal struct type
+  any-generic-type ::= protocol 'P'              // nominal protocol type
+  any-generic-type ::= context decl-name 'a'     // typealias type (used in DWARF and USRs)
 
-  nominal-type ::= 'S' KNOWN-TYPE-KIND       // known nominal type substitution
-  nominal-type ::= 'S' NATURAL KNOWN-TYPE-KIND    // repeated known type substitutions of the same kind
+  any-generic-type ::= 'S' KNOWN-TYPE-KIND       // known nominal type substitution
+  any-generic-type ::= 'S' NATURAL KNOWN-TYPE-KIND    // repeated known type substitutions of the same kind
 
   KNOWN-TYPE-KIND ::= 'a'                    // Swift.Array
   KNOWN-TYPE-KIND ::= 'b'                    // Swift.Bool
@@ -995,7 +996,6 @@ Types
   type ::= 'Bp'                              // Builtin.RawPointer
   type ::= type 'Bv' NATURAL '_'             // Builtin.Vec<n>x<type>
   type ::= 'Bw'                              // Builtin.Word
-  type ::= context decl-name 'a'             // Type alias (DWARF only)
   type ::= function-signature 'c'            // function type
   type ::= function-signature 'X' FUNCTION-KIND // special function type
   type ::= bound-generic-type
@@ -1042,7 +1042,7 @@ Types
 
   type ::= archetype
   type ::= associated-type
-  type ::= nominal-type
+  type ::= any-generic-type
   type ::= protocol-list 'p'                 // existential type
   type ::= protocol-list superclass 'Xc'     // existential type with superclass
   type ::= protocol-list 'Xl'                // existential type with AnyObject

include/swift/AST/ASTMangler.h

@@ -38,6 +38,11 @@ class ASTMangler : public Mangler {
   /// If enabled, Arche- and Alias types are mangled with context.
   bool DWARFMangling;
 
+  /// If enabled, entities that ought to have names but don't get a placeholder.
+  ///
+  /// If disabled, it is an error to try to mangle such an entity.
+  bool AllowNamelessEntities = false;
+
 public:
   enum class SymbolKind {
     Default,
@@ -122,7 +127,7 @@ class ASTMangler : public Mangler {
 
   std::string mangleTypeAsContextUSR(const NominalTypeDecl *type);
 
-  std::string mangleDeclAsUSR(ValueDecl *Decl, StringRef USRPrefix);
+  std::string mangleDeclAsUSR(const ValueDecl *Decl, StringRef USRPrefix);
 
   std::string mangleAccessorEntityAsUSR(AccessorKind kind,
                                         AddressorKind addressorKind,
@@ -167,7 +172,7 @@ class ASTMangler : public Mangler {
 
   void appendProtocolName(const ProtocolDecl *protocol);
 
-  void appendNominalType(const NominalTypeDecl *decl);
+  void appendAnyGenericType(const GenericTypeDecl *decl);
 
   void appendFunctionType(AnyFunctionType *fn, bool forceSingleParam);
 
@@ -207,7 +212,7 @@ class ASTMangler : public Mangler {
 
   void appendDeclType(const ValueDecl *decl, bool isFunctionMangling = false);
 
-  bool tryAppendStandardSubstitution(const NominalTypeDecl *type);
+  bool tryAppendStandardSubstitution(const GenericTypeDecl *type);
 
   void appendConstructorEntity(const ConstructorDecl *ctor, bool isAllocating);
 

include/swift/Basic/Mangler.h

@@ -14,14 +14,13 @@
 #define SWIFT_BASIC_MANGLER_H
 
 #include "swift/Demangling/ManglingUtils.h"
+#include "swift/Basic/LLVM.h"
 #include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/StringMap.h"
 #include "llvm/Support/raw_ostream.h"
 
-using llvm::StringRef;
-using llvm::ArrayRef;
-
 namespace swift {
 namespace Mangle {
 
@@ -39,7 +38,7 @@ class Mangler {
   friend class SubstitutionMerging;
 
   /// The storage for the mangled symbol.
-  llvm::SmallVector<char, 128> Storage;
+  llvm::SmallString<128> Storage;
 
   /// The output stream for the mangled symbol.
   llvm::raw_svector_ostream Buffer;
@@ -106,7 +105,7 @@ class Mangler {
   void finalize(llvm::raw_ostream &stream);
 
   /// Verify that demangling and remangling works.
-  void verify(const std::string &mangledName);
+  static void verify(StringRef mangledName);
 
   /// Appends a mangled identifier string.
   void appendIdentifier(StringRef ident);

include/swift/Demangling/DemangleNodes.def

@@ -149,7 +149,7 @@ NODE(Tuple)
 NODE(TupleElement)
 NODE(TupleElementName)
 NODE(Type)
-NODE(TypeAlias)
+CONTEXT_NODE(TypeAlias)
 NODE(TypeList)
 NODE(TypeMangling)
 NODE(TypeMetadata)

include/swift/Demangling/Demangler.h

@@ -405,8 +405,7 @@ class Demangler : public NodeFactory {
   NodePointer popTypeAndGetChild();
   NodePointer popTypeAndGetNominal();
   NodePointer demangleBuiltinType();
-  NodePointer demangleNominalType(Node::Kind kind);
-  NodePointer demangleTypeAlias();
+  NodePointer demangleAnyGenericType(Node::Kind kind);
   NodePointer demangleExtensionContext();
   NodePointer demanglePlainFunction();
   NodePointer popFunctionType(Node::Kind kind);