[torque-ls] Support "goto-definition" for Types in extends clause

Type declaration may contain a parent type in an "extends" clause.
This CL changes the token type of the name after such a clause
from std::string to Identifier*. The resulting SourcePosition is then
used to implement the "goto-definition" link from that name to the
definition of the parent type.

R=mvstanton@chromium.org

Bug: v8:8880
Change-Id: I9ea6cd83e4d6ef535906e36626f64d458c7d0270
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1511481
Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Reviewed-by: Michael Stanton <mvstanton@chromium.org>
Commit-Queue: Simon Zünd <szuend@chromium.org>
Cr-Commit-Position: refs/heads/master@{#60179}

src/torque/ast.h

@@ -665,18 +665,18 @@ struct BlockStatement : Statement {
 struct TypeDeclaration : Declaration {
   DEFINE_AST_NODE_LEAF_BOILERPLATE(TypeDeclaration)
   TypeDeclaration(SourcePosition pos, Identifier* name, bool transient,
-                  base::Optional<std::string> extends,
+                  base::Optional<Identifier*> extends,
                   base::Optional<std::string> generates,
                   base::Optional<std::string> constexpr_generates)
       : Declaration(kKind, pos),
         name(name),
         transient(transient),
-        extends(std::move(extends)),
+        extends(extends),
         generates(std::move(generates)),
         constexpr_generates(std::move(constexpr_generates)) {}
   Identifier* name;
   bool transient;
-  base::Optional<std::string> extends;
+  base::Optional<Identifier*> extends;
   base::Optional<std::string> generates;
   base::Optional<std::string> constexpr_generates;
 };

src/torque/declaration-visitor.cc

@@ -348,9 +348,12 @@ void DeclarationVisitor::Visit(TypeDeclaration* decl) {
         MakeNode<Identifier>(CONSTEXPR_TYPE_PREFIX + decl->name->value);
     constexpr_name->pos = decl->name->pos;
 
-    base::Optional<std::string> constexpr_extends;
-    if (decl->extends)
-      constexpr_extends = CONSTEXPR_TYPE_PREFIX + *decl->extends;
+    base::Optional<Identifier*> constexpr_extends;
+    if (decl->extends) {
+      constexpr_extends =
+          MakeNode<Identifier>(CONSTEXPR_TYPE_PREFIX + (*decl->extends)->value);
+      (*constexpr_extends)->pos = (*decl->extends)->pos;
+    }
     Declarations::DeclareAbstractType(constexpr_name, false,
                                       *decl->constexpr_generates, type,
                                       constexpr_extends);

src/torque/declarations.cc

@@ -160,11 +160,16 @@ Namespace* Declarations::DeclareNamespace(const std::string& name) {
 const AbstractType* Declarations::DeclareAbstractType(
     const Identifier* name, bool transient, std::string generated,
     base::Optional<const AbstractType*> non_constexpr_version,
-    const base::Optional<std::string>& parent) {
+    const base::Optional<Identifier*>& parent) {
   CheckAlreadyDeclared<TypeAlias>(name->value, "type");
   const Type* parent_type = nullptr;
   if (parent) {
-    parent_type = LookupType(QualifiedName{*parent});
+    auto parent_type_alias = LookupTypeAlias(QualifiedName{(*parent)->value});
+    parent_type = parent_type_alias->type();
+    if (GlobalContext::collect_language_server_data()) {
+      LanguageServerData::AddDefinition(
+          (*parent)->pos, parent_type_alias->GetDeclarationPosition());
+    }
   }
   if (generated == "" && parent) {
     generated = parent_type->GetGeneratedTNodeTypeName();

src/torque/declarations.h

@@ -77,7 +77,7 @@ class Declarations {
   static const AbstractType* DeclareAbstractType(
       const Identifier* name, bool transient, std::string generated,
       base::Optional<const AbstractType*> non_constexpr_version,
-      const base::Optional<std::string>& parent = {});
+      const base::Optional<Identifier*>& parent = {});
 
   static void DeclareType(const Identifier* name, const Type* type,
                           bool redeclaration);

src/torque/earley-parser.h

@@ -45,6 +45,7 @@ enum class ParseResultHolderBase::TypeId {
   kStdVectorOfString,
   kExpressionPtr,
   kIdentifierPtr,
+  kOptionalIdentifierPtr,
   kLocationExpressionPtr,
   kStatementPtr,
   kDeclarationPtr,

src/torque/torque-parser.cc

@@ -64,6 +64,10 @@ template <>
 V8_EXPORT_PRIVATE const ParseResultTypeId ParseResultHolder<Identifier*>::id =
     ParseResultTypeId::kIdentifierPtr;
 template <>
+V8_EXPORT_PRIVATE const ParseResultTypeId
+    ParseResultHolder<base::Optional<Identifier*>>::id =
+        ParseResultTypeId::kOptionalIdentifierPtr;
+template <>
 V8_EXPORT_PRIVATE const ParseResultTypeId
     ParseResultHolder<LocationExpression*>::id =
         ParseResultTypeId::kLocationExpressionPtr;
@@ -521,12 +525,12 @@ base::Optional<ParseResult> MakeTypeDeclaration(
   if (!IsValidTypeName(name->value)) {
     NamingConventionError("Type", name->value, "UpperCamelCase");
   }
-  auto extends = child_results->NextAs<base::Optional<std::string>>();
+  auto extends = child_results->NextAs<base::Optional<Identifier*>>();
   auto generates = child_results->NextAs<base::Optional<std::string>>();
   auto constexpr_generates =
       child_results->NextAs<base::Optional<std::string>>();
-  Declaration* result = MakeNode<TypeDeclaration>(
-      name, transient, std::move(extends), std::move(generates),
+  Declaration* result =
+      MakeNode<TypeDeclaration>(name, transient, extends, std::move(generates),
                                 std::move(constexpr_generates));
   return ParseResult{result};
 }
@@ -1604,7 +1608,7 @@ struct TorqueGrammar : Grammar {
             List<StructFieldExpression>(&structField), Token("}")},
            MakeStructDeclaration),
       Rule({CheckIf(Token("transient")), Token("type"), &name,
-            Optional<std::string>(Sequence({Token("extends"), &identifier})),
+            Optional<Identifier*>(Sequence({Token("extends"), &name})),
             Optional<std::string>(
                 Sequence({Token("generates"), &externalString})),
             Optional<std::string>(

test/unittests/torque/ls-server-data-unittest.cc

@@ -52,6 +52,23 @@ TEST(LanguageServer, GotoTypeDefinition) {
   EXPECT_EQ(*maybe_position, (SourcePosition{id, {3, 5}, {3, 7}}));
 }
 
+TEST(LanguageServer, GotoTypeDefinitionExtends) {
+  const std::string source =
+      "type void;\n"
+      "type never;\n"
+      "type T1 generates 'TNode<T1>';\n"
+      "type T2 extends T1 generates 'TNode<T2>';";
+
+  TestCompiler compiler;
+  compiler.Compile(source);
+
+  // Find the definition for 'T1' of the extends clause on line 3.
+  const SourceId id = SourceFileMap::GetSourceId("<torque>");
+  auto maybe_position = LanguageServerData::FindDefinition(id, {3, 16});
+  ASSERT_TRUE(maybe_position.has_value());
+  EXPECT_EQ(*maybe_position, (SourcePosition{id, {2, 5}, {2, 7}}));
+}
+
 }  // namespace torque
 }  // namespace internal
 }  // namespace v8