Maintain type/name of Incomplete type

Author: ttreyer

oi/type_graph/DrgnParser.cpp

@@ -87,43 +87,55 @@ Type& DrgnParser::enumerateType(struct drgn_type* type) {
   if (auto it = drgn_types_.find(type); it != drgn_types_.end())
     return it->second;
 
-  if (!drgn_utils::isSizeComplete(type) &&
-      drgn_type_kind(type) != DRGN_TYPE_VOID) {
-    return makeType<Primitive>(nullptr, Primitive::Kind::Incomplete);
-  }
+  bool isTypeIncomplete = !drgn_utils::isSizeComplete(type) &&
+                          drgn_type_kind(type) != DRGN_TYPE_VOID;
 
   enum drgn_type_kind kind = drgn_type_kind(type);
   Type* t = nullptr;
   depth_++;
-  switch (kind) {
-    case DRGN_TYPE_CLASS:
-    case DRGN_TYPE_STRUCT:
-    case DRGN_TYPE_UNION:
-      t = &enumerateClass(type);
-      break;
-    case DRGN_TYPE_ENUM:
-      t = &enumerateEnum(type);
-      break;
-    case DRGN_TYPE_TYPEDEF:
-      t = &enumerateTypedef(type);
-      break;
-    case DRGN_TYPE_POINTER:
-      t = &enumeratePointer(type);
-      break;
-    case DRGN_TYPE_ARRAY:
-      t = &enumerateArray(type);
-      break;
-    case DRGN_TYPE_INT:
-    case DRGN_TYPE_BOOL:
-    case DRGN_TYPE_FLOAT:
-    case DRGN_TYPE_VOID:
-      t = &enumeratePrimitive(type);
-      break;
-    default:
-      throw DrgnParserError{"Unknown drgn type kind: " + std::to_string(kind)};
+  try {
+    switch (kind) {
+      case DRGN_TYPE_CLASS:
+      case DRGN_TYPE_STRUCT:
+      case DRGN_TYPE_UNION:
+        t = &enumerateClass(type);
+        break;
+      case DRGN_TYPE_ENUM:
+        t = &enumerateEnum(type);
+        break;
+      case DRGN_TYPE_TYPEDEF:
+        t = &enumerateTypedef(type);
+        break;
+      case DRGN_TYPE_POINTER:
+        t = &enumeratePointer(type);
+        break;
+      case DRGN_TYPE_ARRAY:
+        t = &enumerateArray(type);
+        break;
+      case DRGN_TYPE_INT:
+      case DRGN_TYPE_BOOL:
+      case DRGN_TYPE_FLOAT:
+      case DRGN_TYPE_VOID:
+        t = &enumeratePrimitive(type);
+        break;
+      default:
+        throw DrgnParserError{"Unknown drgn type kind: " +
+                              std::to_string(kind)};
+    }
+  } catch (const DrgnParserError& e) {
+    if (isTypeIncomplete) {
+      t = &makeType<Primitive>(type, Primitive::Kind::Incomplete);
+    } else {
+      depth_--;
+      throw e;
+    }
   }
   depth_--;
 
+  if (isTypeIncomplete) {
+    return makeType<Incomplete>(nullptr, *t);
+  }
+
   return *t;
 }
 

oi/type_graph/EnforceCompatibility.cpp

@@ -78,6 +78,12 @@ void EnforceCompatibility::visit(Class& c) {
       return true;
 
     if (auto* ptr = dynamic_cast<Pointer*>(&member.type())) {
+      if (auto* incomplete = dynamic_cast<Incomplete*>(&ptr->pointeeType())) {
+        // This is a pointer to an incomplete type. CodeGen v1 does not record
+        // the pointer's address in this case.
+        return true;
+      }
+
       if (auto* primitive = dynamic_cast<Primitive*>(&ptr->pointeeType())) {
         if (primitive->kind() == Primitive::Kind::Incomplete) {
           // This is a pointer to an incomplete type. CodeGen v1 does not record

oi/type_graph/Printer.cpp

@@ -36,6 +36,12 @@ void Printer::print(const Type& type) {
   depth_--;
 }
 
+void Printer::visit(const Incomplete& i) {
+  prefix();
+  out_ << "Incomplete:" << std::endl;
+  print(i.underlyingType());
+}
+
 void Printer::visit(const Class& c) {
   if (prefix(c))
     return;

oi/type_graph/Printer.h

@@ -32,6 +32,7 @@ class Printer : public ConstVisitor {
 
   void print(const Type& type);
 
+  void visit(const Incomplete& i) override;
   void visit(const Class& c) override;
   void visit(const Container& c) override;
   void visit(const Primitive& p) override;

oi/type_graph/Types.cpp

@@ -29,6 +29,8 @@ namespace oi::detail::type_graph {
 OI_TYPE_LIST
 #undef X
 
+const std::string Incomplete::kName = "void";
+
 std::string Primitive::getName(Kind kind) {
   switch (kind) {
     case Kind::Int8:

oi/type_graph/Types.h

@@ -40,6 +40,7 @@
 #include "oi/EnumBitset.h"
 
 #define OI_TYPE_LIST \
+  X(Incomplete)      \
   X(Class)           \
   X(Container)       \
   X(Primitive)       \
@@ -184,6 +185,49 @@ struct TemplateParam {
   std::optional<std::string> value;
 };
 
+/*
+ * Incomplete
+ *
+ * A wrapper around a type we couldn't determine the size of.
+ */
+class Incomplete : public Type {
+ public:
+  Incomplete(Type& underlyingType) : underlyingType_(underlyingType) {
+  }
+
+  static inline constexpr bool has_node_id = false;
+
+  DECLARE_ACCEPT
+
+  const std::string& name() const override {
+    return kName;
+  }
+
+  std::string_view inputName() const override {
+    return underlyingType_.inputName();
+  }
+
+  size_t size() const override {
+    return 0;
+  }
+
+  uint64_t align() const override {
+    return 0;
+  }
+
+  NodeId id() const override {
+    return -1;
+  }
+
+  Type& underlyingType() const {
+    return underlyingType_;
+  }
+
+ private:
+  Type& underlyingType_;
+  static const std::string kName;
+};
+
 /*
  * Class
  *

oi/type_graph/Visitor.h

@@ -71,6 +71,8 @@ class RecursiveVisitor : public Visitor {
     if (type)
       accept(*type);
   }
+  virtual void visit(Incomplete&) {
+  }
   virtual void visit(Class& c) {
     for (const auto& param : c.templateParams) {
       accept(param.type());

test/TypeGraphParser.cpp

@@ -211,6 +211,9 @@ Type& TypeGraphParser::parseType(std::string_view& input, size_t rootIndent) {
                                  std::to_string(refId)};
 
     type = &it->second.get();
+  } else if (nodeTypeName == "Incomplete") {
+    auto& underlyingType = parseType(input, indent + 2);
+    type = &typeGraph_.makeType<Incomplete>(underlyingType);
   } else if (nodeTypeName == "Class" || nodeTypeName == "Struct" ||
              nodeTypeName == "Union") {
     // Format: "Class: MyClass (size: 12)"

test/test_drgn_parser.cpp

@@ -367,7 +367,8 @@ TEST_F(DrgnParserTest, PointerNoFollow) {
 TEST_F(DrgnParserTest, PointerIncomplete) {
   test("oid_test_case_pointers_incomplete_raw", R"(
 [0] Pointer
-      Primitive: void (incomplete)
+      Incomplete:
+        Primitive: void (incomplete)
 )");
 }