[torque] Continue past error when return type is missing

Bug: v8:7793
Change-Id: I1d5f85921f06e22679053cc7b2fe0a1371562048
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3206270
Commit-Queue: Nico Hartmann <nicohartmann@chromium.org>
Reviewed-by: Nico Hartmann <nicohartmann@chromium.org>
Cr-Commit-Position: refs/heads/main@{#77245}

src/torque/torque-parser.cc

@@ -523,6 +523,15 @@ base::Optional<ParseResult> MakeDebugStatement(
   return ParseResult{result};
 }
 
+base::Optional<ParseResult> DeprecatedMakeVoidType(
+    ParseResultIterator* child_results) {
+  Error("Default void return types are deprecated. Add `: void`.");
+  TypeExpression* result = MakeNode<BasicTypeExpression>(
+      std::vector<std::string>{}, MakeNode<Identifier>("void"),
+      std::vector<TypeExpression*>{});
+  return ParseResult{result};
+}
+
 base::Optional<ParseResult> MakeExternalMacro(
     ParseResultIterator* child_results) {
   auto transitioning = child_results->NextAs<bool>();
@@ -2262,6 +2271,10 @@ struct TorqueGrammar : Grammar {
        TryOrDefault<TypeList>(Sequence({Token("("), typeList, Token(")")}))},
       MakeLabelAndTypes)};
 
+  // Result: TypeExpression*
+  Symbol returnType = {Rule({Token(":"), &type}),
+                       Rule({}, DeprecatedMakeVoidType)};
+
   // Result: LabelAndTypesVector
   Symbol* optionalLabelList{TryOrDefault<LabelAndTypesVector>(
       Sequence({Token("labels"),
@@ -2569,7 +2582,7 @@ struct TorqueGrammar : Grammar {
   Symbol method = {Rule(
       {CheckIf(Token("transitioning")),
        Optional<std::string>(Sequence({Token("operator"), &externalString})),
-       Token("macro"), &name, &parameterListNoVararg, Token(":"), &type,
+       Token("macro"), &name, &parameterListNoVararg, &returnType,
        optionalLabelList, &block},
       MakeMethodDeclaration)};
 
@@ -2616,7 +2629,7 @@ struct TorqueGrammar : Grammar {
            AsSingletonVector<Declaration*, MakeTypeAliasDeclaration>()),
       Rule({Token("intrinsic"), &intrinsicName,
             TryOrDefault<GenericParameters>(&genericParameters),
-            &parameterListNoVararg, Token(":"), &type, &optionalBody},
+            &parameterListNoVararg, &returnType, &optionalBody},
            AsSingletonVector<Declaration*, MakeIntrinsicDeclaration>()),
       Rule({Token("extern"), CheckIf(Token("transitioning")),
             Optional<std::string>(
@@ -2624,33 +2637,32 @@ struct TorqueGrammar : Grammar {
             Token("macro"),
             Optional<std::string>(Sequence({&identifier, Token("::")})), &name,
             TryOrDefault<GenericParameters>(&genericParameters),
-            &typeListMaybeVarArgs, Token(":"), &type, optionalLabelList,
-            Token(";")},
+            &typeListMaybeVarArgs, &returnType, optionalLabelList, Token(";")},
            AsSingletonVector<Declaration*, MakeExternalMacro>()),
       Rule({Token("extern"), CheckIf(Token("transitioning")),
             CheckIf(Token("javascript")), Token("builtin"), &name,
             TryOrDefault<GenericParameters>(&genericParameters),
-            &typeListMaybeVarArgs, Token(":"), &type, Token(";")},
+            &typeListMaybeVarArgs, &returnType, Token(";")},
            AsSingletonVector<Declaration*, MakeExternalBuiltin>()),
       Rule({Token("extern"), CheckIf(Token("transitioning")), Token("runtime"),
-            &name, &typeListMaybeVarArgs, Token(":"), &type, Token(";")},
+            &name, &typeListMaybeVarArgs, &returnType, Token(";")},
            AsSingletonVector<Declaration*, MakeExternalRuntime>()),
       Rule({annotations, CheckIf(Token("transitioning")),
             Optional<std::string>(
                 Sequence({Token("operator"), &externalString})),
             Token("macro"), &name,
             TryOrDefault<GenericParameters>(&genericParameters),
-            &parameterListNoVararg, Token(":"), &type, optionalLabelList,
+            &parameterListNoVararg, &returnType, optionalLabelList,
             &optionalBody},
            AsSingletonVector<Declaration*, MakeTorqueMacroDeclaration>()),
       Rule({CheckIf(Token("transitioning")), CheckIf(Token("javascript")),
             Token("builtin"), &name,
             TryOrDefault<GenericParameters>(&genericParameters),
-            &parameterListAllowVararg, Token(":"), &type, &optionalBody},
+            &parameterListAllowVararg, &returnType, &optionalBody},
            AsSingletonVector<Declaration*, MakeTorqueBuiltinDeclaration>()),
       Rule({CheckIf(Token("transitioning")), &name,
             &genericSpecializationTypeList, &parameterListAllowVararg,
-            Token(":"), &type, optionalLabelList, &block},
+            &returnType, optionalLabelList, &block},
            AsSingletonVector<Declaration*, MakeSpecializationDeclaration>()),
       Rule({Token("#include"), &externalString},
            AsSingletonVector<Declaration*, MakeCppIncludeDeclaration>()),