IRGen: Emit typerefs for all builtin types referenced from reflection metadata sections

In order to perform layout, the remote mirrors library needs to know
about the size, alignment and extra inhabitants of builtin types.

Ideally we would emit a reflection info section in libswiftRuntime.o,
but in the meantime just duplicate builtin type metadata for all
builtin types referenced from the current module instead.

In practice only the stdlib and a handful of overlays like the SIMD
overlay use builtin types, and only a few at a time.

Tested manually by running swift-reflection-tool on the standard
library -- I'll add automated tests by using -parse-stdlib to
reference Builtin types in a subsequent patch that adds more layout
logic.

NFC if -enable-reflection-metadata is off.

Author: slavapestov

include/swift/Reflection/Records.h

@@ -22,6 +22,8 @@
 namespace swift {
 namespace reflection {
 
+// Field records describe the type of a single stored property or case member
+// of a class, struct or enum.
 class FieldRecordFlags {
   using int_type = uint32_t;
   enum : int_type {
@@ -97,6 +99,8 @@ struct FieldRecordIterator {
   }
 };
 
+// Field descriptors contain a collection of field records for a single
+// class, struct or enum declaration.
 struct FieldDescriptor {
   const FieldRecord *getFieldRecordBuffer() const {
     return reinterpret_cast<const FieldRecord *>(this + 1);
@@ -127,6 +131,37 @@ struct FieldDescriptor {
   }
 };
 
+class FieldDescriptorIterator
+  : public std::iterator<std::forward_iterator_tag, FieldDescriptor> {
+public:
+  const void *Cur;
+  const void * const End;
+  FieldDescriptorIterator(const void *Cur, const void * const End)
+    : Cur(Cur), End(End) {}
+
+  const FieldDescriptor &operator*() const {
+    return *reinterpret_cast<const FieldDescriptor *>(Cur);
+  }
+
+  FieldDescriptorIterator &operator++() {
+    const auto &FR = this->operator*();
+    const void *Next = reinterpret_cast<const char *>(Cur)
+      + sizeof(FieldDescriptor) + FR.NumFields * FR.FieldRecordSize;
+    Cur = Next;
+    return *this;
+  }
+
+  bool operator==(FieldDescriptorIterator const &other) const {
+    return Cur == other.Cur && End == other.End;
+  }
+
+  bool operator!=(FieldDescriptorIterator const &other) const {
+    return !(*this == other);
+  }
+};
+
+// Associated type records describe the mapping from an associated
+// type to the type witness of a conformance.
 class AssociatedTypeRecord {
   const RelativeDirectPointer<const char> Name;
   const RelativeDirectPointer<const char> SubstitutedTypeName;
@@ -179,6 +214,8 @@ struct AssociatedTypeRecordIterator {
   }
 };
 
+// An associated type descriptor contains a collection of associated
+// type records for a conformance.
 struct AssociatedTypeDescriptor {
   const RelativeDirectPointer<const char> ConformingTypeName;
   const RelativeDirectPointer<const char> ProtocolTypeName;
@@ -243,36 +280,50 @@ class AssociatedTypeIterator
   }
 };
 
-class FieldDescriptorIterator
-  : public std::iterator<std::forward_iterator_tag, FieldDescriptor> {
+// Builtin type records describe basic layout information about
+// any builtin types referenced from the other sections.
+class BuiltinTypeDescriptor {
+  const RelativeDirectPointer<const char> TypeName;
+
+public:
+  uint32_t Size;
+  uint32_t Alignment;
+  uint32_t Stride;
+  uint32_t NumExtraInhabitants;
+
+  std::string getMangledTypeName() const {
+    return TypeName.get();
+  }
+};
+
+class BuiltinTypeDescriptorIterator
+  : public std::iterator<std::forward_iterator_tag, BuiltinTypeDescriptor> {
 public:
   const void *Cur;
   const void * const End;
-  FieldDescriptorIterator(const void *Cur, const void * const End)
+  BuiltinTypeDescriptorIterator(const void *Cur, const void * const End)
     : Cur(Cur), End(End) {}
 
-  const FieldDescriptor &operator*() const {
-    return *reinterpret_cast<const FieldDescriptor *>(Cur);
+  const BuiltinTypeDescriptor &operator*() const {
+    return *reinterpret_cast<const BuiltinTypeDescriptor *>(Cur);
   }
 
-  FieldDescriptorIterator &operator++() {
-    const auto &FR = this->operator*();
+  BuiltinTypeDescriptorIterator &operator++() {
     const void *Next = reinterpret_cast<const char *>(Cur)
-      + sizeof(FieldDescriptor) + FR.NumFields * FR.FieldRecordSize;
+      + sizeof(BuiltinTypeDescriptor);
     Cur = Next;
     return *this;
   }
 
-  bool operator==(FieldDescriptorIterator const &other) const {
+  bool operator==(BuiltinTypeDescriptorIterator const &other) const {
     return Cur == other.Cur && End == other.End;
   }
 
-  bool operator!=(FieldDescriptorIterator const &other) const {
+  bool operator!=(BuiltinTypeDescriptorIterator const &other) const {
     return !(*this == other);
   }
 };
 
-
 } // end namespace reflection
 } // end namespace swift
 

include/swift/Reflection/ReflectionContext.h

@@ -39,17 +39,17 @@ using swift::remote::RemoteAddress;
 template <typename Iterator>
 class ReflectionSection {
   using const_iterator = Iterator;
-  const void * const Begin;
-  const void * const End;
+  const void * Begin;
+  const void * End;
 
 public:
-  ReflectionSection(const void * const Begin,
-                    const void * const End)
+  ReflectionSection(const void * Begin,
+                    const void * End)
   : Begin(Begin), End(End) {}
 
   ReflectionSection(uint64_t Begin, uint64_t End)
-  : Begin(reinterpret_cast<const void * const>(Begin)),
-  End(reinterpret_cast<const void * const>(End)) {}
+  : Begin(reinterpret_cast<const void *>(Begin)),
+    End(reinterpret_cast<const void *>(End)) {}
 
   void *startAddress() {
     return const_cast<void *>(Begin);
@@ -177,14 +177,16 @@ class TypeRefBuilder {
 
 using FieldSection = ReflectionSection<FieldDescriptorIterator>;
 using AssociatedTypeSection = ReflectionSection<AssociatedTypeIterator>;
+using BuiltinTypeSection = ReflectionSection<BuiltinTypeDescriptorIterator>;
 using GenericSection = ReflectionSection<const void *>;
 
 struct ReflectionInfo {
   std::string ImageName;
   FieldSection fieldmd;
   AssociatedTypeSection assocty;
-  GenericSection reflstr;
+  BuiltinTypeSection builtin;
   GenericSection typeref;
+  GenericSection reflstr;
 };
 
 
@@ -295,16 +297,34 @@ class ReflectionContext
     }
   }
 
+  void dumpBuiltinTypeSection(std::ostream &OS) {
+    for (const auto &sections : ReflectionInfos) {
+      for (const auto &descriptor : sections.builtin) {
+        auto typeName = Demangle::demangleTypeAsString(
+          descriptor.getMangledTypeName());
+
+        OS << typeName << " :\n";
+        OS << "Size: " << descriptor.Size << "\n";
+        OS << "Alignment: " << descriptor.Alignment << "\n";
+        OS << "Stride: " << descriptor.Stride << "\n";
+        OS << "NumExtraInhabitants: " << descriptor.NumExtraInhabitants << "\n";
+      }
+    }
+  }
+
   void dumpAllSections(std::ostream &OS) {
     OS << "FIELDS:\n";
-    for (size_t i = 0; i < 7; ++i) OS << '=';
-    OS << '\n';
+    OS << "=======\n";
     dumpFieldSection(OS);
-    OS << "\nASSOCIATED TYPES:\n";
-    for (size_t i = 0; i < 17; ++i) OS << '=';
     OS << '\n';
+    OS << "ASSOCIATED TYPES:\n";
+    OS << "=================\n";
     dumpAssociatedTypeSection(OS);
     OS << '\n';
+    OS << "BUILTIN TYPES:\n";
+    OS << "==============\n";
+    dumpBuiltinTypeSection(OS);
+    OS << '\n';
   }
 
   TypeRef *

include/swift/SwiftRemoteMirror/SwiftRemoteMirror.h

@@ -51,9 +51,10 @@ void
 swift_reflection_addReflectionInfo(SwiftReflectionContextRef ContextRef,
                                    const char *ImageName,
                                    swift_reflection_section_t fieldmd,
+                                   swift_reflection_section_t builtin,
+                                   swift_reflection_section_t assocty,
                                    swift_reflection_section_t typeref,
-                                   swift_reflection_section_t reflstr,
-                                   swift_reflection_section_t assocty);
+                                   swift_reflection_section_t reflstr);
 
 
 /// Returns an opaque type reference for a metadata pointer, or

lib/IRGen/GenDecl.cpp

@@ -879,15 +879,9 @@ void IRGenModuleDispatcher::emitTypeMetadataRecords() {
   }
 }
 
-void IRGenModuleDispatcher::emitFieldTypeMetadataRecords() {
+void IRGenModuleDispatcher::emitReflectionMetadataRecords() {
   for (auto &m : *this) {
-    m.second->emitFieldTypeMetadataRecords();
-  }
-}
-
-void IRGenModuleDispatcher::emitAssociatedTypeMetadataRecords() {
-  for (auto &m : *this) {
-    m.second->emitAssociatedTypeMetadataRecords();
+    m.second->emitReflectionMetadataRecords();
   }
 }