Merge pull request #72692 from DougGregor/future-proof-invertible-mangling

Future-proof the mangling of invertible protocols

Author: DougGregor

docs/ABI/Mangling.rst

@@ -1011,9 +1011,6 @@ now codified into the ABI; the index 0 is therefore reserved.
 
   generic-param-pack-marker ::= 'Rv' GENERIC_PARAM-INDEX   // generic parameter pack marker
 
-  INVERTIBLE-KIND ::= 'c'  // Copyable
-  INVERTIBLE-KIND ::= 'e'  // Escapable
-
   GENERIC-PARAM-COUNT ::= 'z'                // zero parameters
   GENERIC-PARAM-COUNT ::= INDEX              // N+1 parameters
 
@@ -1022,7 +1019,10 @@ now codified into the ABI; the index 0 is therefore reserved.
   requirement ::= protocol assoc-type-list 'RP' GENERIC-PARAM-INDEX // protocol requirement on associated type at depth
   requirement ::= protocol substitution 'RQ'                        // protocol requirement with substitution
 #if SWIFT_RUNTIME_VERSION >= 6.0
-  requirement ::= 'Ri' INVERTIBLE-KIND GENERIC-PARAM-INDEX          // inverse requirement
+  requirement ::= 'Ri' INDEX GENERIC-PARAM-INDEX                    // inverse requirement on generic parameter where INDEX is the bit number
+  requirement ::= substitution 'RI' INDEX                           // inverse requirement with substitution
+  requirement ::= assoc-type-name 'Rj' INDEX GENERIC-PARAM-INDEX    // inverse requirement on associated type
+  requirement ::= assoc-type-list 'RJ' INDEX GENERIC-PARAM-INDEX    // inverse requirement on associated type at depth
 #endif
   requirement ::= type 'Rb' GENERIC-PARAM-INDEX                     // base class requirement
   requirement ::= type assoc-type-name 'Rc' GENERIC-PARAM-INDEX     // base class requirement on associated type

include/swift/ABI/SuppressibleProtocols.def

@@ -19,15 +19,13 @@
 //   Name: The name of the protocol, e.g., Copyable
 //   Bit: The bit in the set bitset of suppressible protocols that is used
 //        to indicate this.
-//   MangleChar: The character used for the name mangling to refer to this
-//               protocol.
 //===----------------------------------------------------------------------===//
 
 #ifndef SUPPRESSIBLE_PROTOCOL
 #  error Must define SUPPRESSIBLE_PROTOCOL macro before including this file
 #endif
 
-SUPPRESSIBLE_PROTOCOL(Copyable, 0, 'c')
-SUPPRESSIBLE_PROTOCOL(Escapable, 1, 'e')
+SUPPRESSIBLE_PROTOCOL(Copyable, 0)
+SUPPRESSIBLE_PROTOCOL(Escapable, 1)
 
 #undef SUPPRESSIBLE_PROTOCOL

include/swift/ABI/SuppressibleProtocols.h

@@ -26,7 +26,7 @@ namespace swift {
 /// Describes a "suppressible" protocol, such as Copyable, which is assumed to
 /// hold for all types unless explicitly suppressed.
 enum class SuppressibleProtocolKind : uint8_t {
-#define SUPPRESSIBLE_PROTOCOL(Name, Bit, MangleChar) Name = Bit,
+#define SUPPRESSIBLE_PROTOCOL(Name, Bit) Name = Bit,
 #include "swift/ABI/SuppressibleProtocols.def"
 };
 
@@ -72,7 +72,7 @@ class SuppressibleProtocolSet {
   /// Clear out all of the protocols from the set.
   void clear() { bits = 0; }
 
-#define SUPPRESSIBLE_PROTOCOL(Name, Bit, MangleChar) \
+#define SUPPRESSIBLE_PROTOCOL(Name, Bit)             \
   bool contains##Name() const {                      \
     return contains(SuppressibleProtocolKind::Name); \
   }
@@ -82,7 +82,7 @@ class SuppressibleProtocolSet {
   /// protocols.
   static SuppressibleProtocolSet allKnown() {
     SuppressibleProtocolSet result;
-#define SUPPRESSIBLE_PROTOCOL(Name, Bit, MangleChar)    \
+#define SUPPRESSIBLE_PROTOCOL(Name, Bit)           \
     result.insert(SuppressibleProtocolKind::Name);
 #include "swift/ABI/SuppressibleProtocols.def"
     return result;
@@ -213,7 +213,7 @@ class SuppressibleProtocolSet {
 static inline const char *
 getSuppressibleProtocolKindName(SuppressibleProtocolKind kind) {
   switch (kind) {
-#define SUPPRESSIBLE_PROTOCOL(Name, Bit, MangleChar)    \
+#define SUPPRESSIBLE_PROTOCOL(Name, Bit)             \
   case SuppressibleProtocolKind::Name: return #Name;
 #include "swift/ABI/SuppressibleProtocols.def"
   }

include/swift/AST/ASTMangler.h

@@ -596,6 +596,24 @@ class ASTMangler : public Mangler {
                               GenericSignature contextSig,
                               BaseEntitySignature &base);
 
+  /// Describes how the subject of a requirement was mangled.
+  struct RequirementSubject {
+    enum Kind {
+      GenericParameter,
+      AssociatedType,
+      AssociatedTypeAtDepth,
+      Substitution
+    } kind;
+
+    /// Generic parameter at the base, if there is one. Valid for everything
+    /// except Substitution subjects.
+    GenericTypeParamType *gpBase = nullptr;
+  };
+
+  /// Append the subject of a generic requirement and state what kind it is.
+  RequirementSubject appendRequirementSubject(
+      CanType subjectType, GenericSignature sig);
+
   /// Append a requirement to the mangling.
   ///
   /// \param reqt The requirement to mangle

include/swift/AST/InvertibleProtocolKind.h

@@ -19,14 +19,11 @@
 #define SWIFT_AST_INVERTIBLEPROTOCOLKIND_H
 
 #include <stdint.h>
+#include <swift/ABI/SuppressibleProtocols.h>
 
 namespace swift {
 
-enum class InvertibleProtocolKind : uint8_t {
-#define INVERTIBLE_PROTOCOL_WITH_NAME(Id, Name) Id,
-#include "swift/AST/KnownProtocols.def"
-};
-
+typedef SuppressibleProtocolKind InvertibleProtocolKind;
 
 } // end namespace swift
 

include/swift/AST/KnownProtocols.def

@@ -136,7 +136,7 @@ PROTOCOL(AsyncIteratorProtocol)
 
 PROTOCOL(FloatingPoint)
 
-#define SUPPRESSIBLE_PROTOCOL(Name, Bit, MangleChar) \
+#define SUPPRESSIBLE_PROTOCOL(Name, Bit) \
     INVERTIBLE_PROTOCOL_WITH_NAME(Name, #Name)
 #include "swift/ABI/SuppressibleProtocols.def"
 

include/swift/AST/KnownProtocols.h

@@ -73,9 +73,6 @@ KnownProtocolKind getKnownProtocolKind(InvertibleProtocolKind ip);
 void simple_display(llvm::raw_ostream &out,
                     const InvertibleProtocolKind &value);
 
-SuppressibleProtocolKind asSuppressible(InvertibleProtocolKind kind);
-InvertibleProtocolKind asInvertible(SuppressibleProtocolKind kind);
-
 } // end namespace swift
 
 #endif

include/swift/Demangling/TypeDecoder.h

@@ -456,38 +456,15 @@ void decodeRequirement(
     } else if (child->getKind() ==
           Demangle::Node::Kind::DependentGenericInverseConformanceRequirement) {
       // Type child
-      auto constraintNode = child->getChild(1);
+      auto constraintNode = child->getChild(0);
       if (constraintNode->getKind() != Demangle::Node::Kind::Type ||
           constraintNode->getNumChildren() != 1)
         return;
 
-      // Protocol child
-      auto protocolNode = constraintNode->getChild(0);
-      if (protocolNode->getKind() != Demangle::Node::Kind::Protocol ||
-          protocolNode->getNumChildren() != 2)
-        return;
-
-      auto moduleNode = protocolNode->getChild(0);
-      if (moduleNode->getKind() != Demangle::Node::Kind::Module ||
-          moduleNode->getText() != "Swift")
-        return;
-
-      auto protocolNameNode = protocolNode->getChild(1);
-      if (protocolNameNode->getKind() != Demangle::Node::Kind::Identifier)
-        return;
-
-      auto protocolName = protocolNameNode->getText();
-      using OptInvertibleKind = std::optional<InvertibleProtocolKind>;
-      auto protocolKind = llvm::StringSwitch<OptInvertibleKind>(protocolName)
-#define INVERTIBLE_PROTOCOL_WITH_NAME(Id, Name) \
-          .Case(Name, InvertibleProtocolKind::Id)
-#include "swift/AST/KnownProtocols.def"
-          .Default(std::nullopt);
-      if (!protocolKind)
-        return;
-
+      auto protocolKind =
+          static_cast<SuppressibleProtocolKind>(child->getChild(1)->getIndex());
       inverseRequirements.push_back(
-          Builder.createInverseRequirement(subjectType, *protocolKind));
+          Builder.createInverseRequirement(subjectType, protocolKind));
       continue;
     }
 

lib/AST/ASTContext.cpp

@@ -132,26 +132,10 @@ void swift::simple_display(llvm::raw_ostream &out,
 
 // Metadata stores a 16-bit field for suppressible protocols. Trigger a build
 // error when we assign the 15th bit so we can think about what to do.
-#define SUPPRESSIBLE_PROTOCOL(Name, Bit, MangleChar) \
+#define SUPPRESSIBLE_PROTOCOL(Name, Bit) \
   static_assert(Bit < 15);
 #include "swift/ABI/SuppressibleProtocols.def"
 
-SuppressibleProtocolKind swift::asSuppressible(InvertibleProtocolKind kind) {
-  switch (kind) {
-#define SUPPRESSIBLE_PROTOCOL(Name, Bit, MangleChar) \
-    case InvertibleProtocolKind::Name: return SuppressibleProtocolKind::Name;
-#include "swift/ABI/SuppressibleProtocols.def"
-  }
-}
-
-InvertibleProtocolKind swift::asInvertible(SuppressibleProtocolKind kind) {
-  switch (kind) {
-#define SUPPRESSIBLE_PROTOCOL(Name, Bit, MangleChar) \
-    case SuppressibleProtocolKind::Name: return InvertibleProtocolKind::Name;
-#include "swift/ABI/SuppressibleProtocols.def"
-  }
-}
-
 namespace {
 enum class SearchPathKind : uint8_t {
   Import = 1 << 0,