[torque] Add Lint errors for naming convention violations

This CL adds naming convention errors for:
  - Variable names
  - Torque Macro/Builtin names
  - Parameter names

R=tebbi@chromium.org

Bug: v8:7793
Change-Id: Icfe20e53524234f0b4534f0102aff6b14121dfbc
Reviewed-on: https://chromium-review.googlesource.com/1213184
Commit-Queue: Simon Zünd <szuend@google.com>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#55758}

src/torque/torque-parser.cc

@@ -233,6 +233,13 @@ base::Optional<ParseResult> MakeParameterListFromNameAndTypeList(
   }
   ParameterList result;
   for (NameAndTypeExpression& pair : params) {
+    if (!IsLowerCamelCase(pair.name)) {
+      std::stringstream sstream;
+      sstream << "Parameter \"" << pair.name << "\" doesn't follow "
+              << "\"lowerCamelCase\" naming convention.";
+      LintError(sstream.str());
+    }
+
     result.names.push_back(std::move(pair.name));
     result.types.push_back(pair.type);
   }
@@ -287,6 +294,13 @@ base::Optional<ParseResult> MakeTorqueMacroDeclaration(
     ParseResultIterator* child_results) {
   auto operator_name = child_results->NextAs<base::Optional<std::string>>();
   auto name = child_results->NextAs<std::string>();
+  if (!IsUpperCamelCase(name)) {
+    std::stringstream sstream;
+    sstream << "Macro \"" << name << "\" doesn't follow "
+            << "\"UpperCamelCase\" naming convention.";
+    LintError(sstream.str());
+  }
+
   auto generic_parameters = child_results->NextAs<GenericParameters>();
   auto args = child_results->NextAs<ParameterList>();
   auto return_type = child_results->NextAs<TypeExpression*>();
@@ -308,6 +322,13 @@ base::Optional<ParseResult> MakeTorqueBuiltinDeclaration(
     ParseResultIterator* child_results) {
   auto javascript_linkage = child_results->NextAs<bool>();
   auto name = child_results->NextAs<std::string>();
+  if (!IsUpperCamelCase(name)) {
+    std::stringstream sstream;
+    sstream << "Builtin \"" << name << "\" doesn't follow "
+            << "\"UpperCamelCase\" naming convention.";
+    LintError(sstream.str());
+  }
+
   auto generic_parameters = child_results->NextAs<GenericParameters>();
   auto args = child_results->NextAs<ParameterList>();
   auto return_type = child_results->NextAs<TypeExpression*>();
@@ -599,6 +620,13 @@ base::Optional<ParseResult> MakeVarDeclarationStatement(
   bool const_qualified = kind == "const";
   if (!const_qualified) DCHECK_EQ("let", kind);
   auto name = child_results->NextAs<std::string>();
+  if (!IsLowerCamelCase(name)) {
+    std::stringstream sstream;
+    sstream << "Variable \"" << name << "\" doesn't follow "
+            << "\"lowerCamelCase\" naming convention.";
+    LintError(sstream.str());
+  }
+
   auto type = child_results->NextAs<TypeExpression*>();
   base::Optional<Expression*> initializer;
   if (child_results->HasNext())

src/torque/utils.cc

@@ -81,6 +81,29 @@ std::string CurrentPositionAsString() {
   std::abort();
 }
 
+void LintError(const std::string& error) {
+  std::cerr << CurrentPositionAsString() << ": Lint error: " << error << "\n";
+}
+
+namespace {
+
+bool ContainsUnderscore(const std::string& s) {
+  if (s.empty()) return false;
+  return s.find("_") != std::string::npos;
+}
+
+}  // namespace
+
+bool IsLowerCamelCase(const std::string& s) {
+  if (s.empty()) return false;
+  return islower(s[0]) && !ContainsUnderscore(s);
+}
+
+bool IsUpperCamelCase(const std::string& s) {
+  if (s.empty()) return false;
+  return isupper(s[0]) && !ContainsUnderscore(s);
+}
+
 std::string CamelifyString(const std::string& underscore_string) {
   std::string result;
   bool word_beginning = true;

src/torque/utils.h

@@ -21,6 +21,10 @@ std::string StringLiteralUnquote(const std::string& s);
 std::string StringLiteralQuote(const std::string& s);
 
 [[noreturn]] void ReportError(const std::string& error);
+void LintError(const std::string& error);
+
+bool IsLowerCamelCase(const std::string& s);
+bool IsUpperCamelCase(const std::string& s);
 
 std::string CamelifyString(const std::string& underscore_string);
 std::string DashifyString(const std::string& underscore_string);