[clang][extract-api] Add support for typedefs

Typedef records consist of the symbol associated with the underlying
TypedefDecl and a SymbolReference to the underlying type. Additionally
typedefs for anonymous TagTypes use the typedef'd name as the symbol
name in their respective records and USRs. As a result the declaration
fragments for the anonymous TagType are those for the associated
typedef. This means that when the user is defining a typedef to a
typedef to a anonymous type, we use a reference the anonymous TagType
itself and do not emit the typedef to the anonymous type in the
generated symbol graph, including in the type destination of further
typedef symbol records.

Differential Revision: https://reviews.llvm.org/D123019

1 files changed, 29 insertions, 0 deletions

diff --git a/clang/lib/ExtractAPI/Serialization/SymbolGraphSerializer.cpp b/clang/lib/ExtractAPI/Serialization/SymbolGraphSerializer.cpp
index 1440ca3..f38a5bb 100644
--- a/clang/lib/ExtractAPI/Serialization/SymbolGraphSerializer.cpp
+++ b/clang/lib/ExtractAPI/Serialization/SymbolGraphSerializer.cpp
@@ -408,6 +408,11 @@ Object serializeSymbolKind(const APIRecord &Record, Language Lang) {
   case APIRecord::RK_MacroDefinition:
     Kind["identifier"] = AddLangPrefix("macro");
     Kind["displayName"] = "Macro";
+    break;
+  case APIRecord::RK_Typedef:
+    Kind["identifier"] = AddLangPrefix("typealias");
+    Kind["displayName"] = "Type Alias";
+    break;
   }
 
   return Kind;
@@ -618,6 +623,27 @@ void SymbolGraphSerializer::serializeMacroDefinitionRecord(
   Symbols.emplace_back(std::move(*Macro));
 }
 
+void SymbolGraphSerializer::serializeTypedefRecord(
+    const TypedefRecord &Record) {
+  // Typedefs of anonymous types have their entries unified with the underlying
+  // type.
+  bool ShouldDrop = Record.UnderlyingType.Name.empty();
+  // enums declared with `NS_OPTION` have a named enum and a named typedef, with
+  // the same name
+  ShouldDrop |= (Record.UnderlyingType.Name == Record.Name);
+  if (ShouldDrop)
+    return;
+
+  auto TypedefPathComponentGuard = makePathComponentGuard(Record.Name);
+  auto Typedef = serializeAPIRecord(Record);
+  if (!Typedef)
+    return;
+
+  (*Typedef)["type"] = Record.UnderlyingType.USR;
+
+  Symbols.emplace_back(std::move(*Typedef));
+}
+
 SymbolGraphSerializer::PathComponentGuard
 SymbolGraphSerializer::makePathComponentGuard(StringRef Component) {
   return PathComponentGuard(PathComponents, Component);
@@ -651,6 +677,9 @@ Object SymbolGraphSerializer::serialize() {
   for (const auto &Macro : API.getMacros())
     serializeMacroDefinitionRecord(*Macro.second);
 
+  for (const auto &Typedef : API.getTypedefs())
+    serializeTypedefRecord(*Typedef.second);
+
   Root["symbols"] = std::move(Symbols);
   Root["relationships"] = std::move(Relationships);