[class] Give a name to initializer functions

Makes for a nicer stack trace

Bug: v8:5367
Change-Id: I6d77907e08c2c4efc7a1b25016c7e83841c7c574
Reviewed-on: https://chromium-review.googlesource.com/1211444
Commit-Queue: Sathya Gunasekaran <gsathya@chromium.org>
Reviewed-by: Adam Klein <adamk@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Reviewed-by: Daniel Ehrenberg <littledan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#55736}

src/messages.cc

@@ -386,6 +386,13 @@ Handle<Object> JSStackFrame::GetMethodName() {
   }
 
   Handle<String> name(function_->shared()->Name(), isolate_);
+
+  // The static initializer function is not a method, so don't add a
+  // class name, just return the function name.
+  if (name->IsUtf8EqualTo(CStrVector("<static_fields_initializer>"), true)) {
+    return name;
+  }
+
   // ES2015 gives getters and setters name prefixes which must
   // be stripped to find the property name.
   if (name->IsUtf8EqualTo(CStrVector("get "), true) ||

src/parsing/parser.cc

@@ -3239,7 +3239,8 @@ void Parser::DeclareClassProperty(const AstRawString* class_name,
 }
 
 FunctionLiteral* Parser::CreateInitializerFunction(
-    DeclarationScope* scope, ZonePtrList<ClassLiteral::Property>* fields) {
+    const char* name, DeclarationScope* scope,
+    ZonePtrList<ClassLiteral::Property>* fields) {
   DCHECK_EQ(scope->function_kind(),
             FunctionKind::kClassFieldsInitializerFunction);
   // function() { .. class fields initializer .. }
@@ -3248,7 +3249,7 @@ FunctionLiteral* Parser::CreateInitializerFunction(
       factory()->NewInitializeClassFieldsStatement(fields, kNoSourcePosition);
   statements->Add(static_fields, zone());
   return factory()->NewFunctionLiteral(
-      ast_value_factory()->empty_string(), scope, statements, 0, 0, 0,
+      ast_value_factory()->GetOneByteString(name), scope, statements, 0, 0, 0,
       FunctionLiteral::kNoDuplicateParameters,
       FunctionLiteral::kAnonymousExpression,
       FunctionLiteral::kShouldEagerCompile, scope->start_position(), true,
@@ -3286,13 +3287,15 @@ Expression* Parser::RewriteClassLiteral(Scope* block_scope,
   FunctionLiteral* static_fields_initializer = nullptr;
   if (class_info->has_static_class_fields) {
     static_fields_initializer = CreateInitializerFunction(
-        class_info->static_fields_scope, class_info->static_fields);
+        "<static_fields_initializer>", class_info->static_fields_scope,
+        class_info->static_fields);
   }
 
   FunctionLiteral* instance_fields_initializer_function = nullptr;
   if (class_info->has_instance_class_fields) {
     instance_fields_initializer_function = CreateInitializerFunction(
-        class_info->instance_fields_scope, class_info->instance_fields);
+        "<instance_fields_initializer>", class_info->instance_fields_scope,
+        class_info->instance_fields);
     class_info->constructor->set_requires_instance_fields_initializer(true);
   }
 

src/parsing/parser.h

@@ -317,7 +317,8 @@ class V8_EXPORT_PRIVATE Parser : public NON_EXPORTED_BASE(ParserBase<Parser>) {
   Variable* CreateSyntheticContextVariable(const AstRawString* synthetic_name,
                                            bool* ok);
   FunctionLiteral* CreateInitializerFunction(
-      DeclarationScope* scope, ZonePtrList<ClassLiteral::Property>* fields);
+      const char* name, DeclarationScope* scope,
+      ZonePtrList<ClassLiteral::Property>* fields);
   V8_INLINE Statement* DeclareClass(const AstRawString* variable_name,
                                     Expression* value,
                                     ZonePtrList<const AstRawString>* names,

test/mjsunit/stack-traces-class-fields.js

@@ -43,13 +43,15 @@ function testClassConstruction() {
 
 // ReferenceError: FAIL is not defined
 //     at thrower
-//     at Function.<anonymous>
+//     at <static_fields_initializer>
 //     at testClassConstruction
 //     at testTrace
-testTrace("during class construction", testClassConstruction, [
-  "thrower",
-  "Function.<anonymous>"
-]);
+testTrace(
+  "during class construction",
+  testClassConstruction,
+  ["thrower", "<static_fields_initializer>"],
+  ["anonymous"]
+);
 
 function testClassConstruction2() {
   class X {
@@ -61,9 +63,7 @@ function testClassConstruction2() {
 //    at thrower
 //    at testClassConstruction2
 //    at testTrace
-testTrace("during class construction2", testClassConstruction2, [
-  "thrower"
-]);
+testTrace("during class construction2", testClassConstruction2, ["thrower"]);
 
 function testClassInstantiation() {
   class X {
@@ -75,15 +75,16 @@ function testClassInstantiation() {
 
 // ReferenceError: FAIL is not defined
 //     at thrower
-//     at X.<anonymous>
+//     at X.<instance_fields_initializer>
 //     at new X
 //     at testClassInstantiation
 //     at testTrace
-testTrace("during class instantiation", testClassInstantiation, [
-  "thrower",
-  "X.<anonymous>",
-  "new X"
-]);
+testTrace(
+  "during class instantiation",
+  testClassInstantiation,
+  ["thrower", "X.<instance_fields_initializer>", "new X"],
+  ["anonymous"]
+);
 
 function testClassInstantiationWithSuper() {
   class Base {}
@@ -97,15 +98,15 @@ function testClassInstantiationWithSuper() {
 
 // ReferenceError: FAIL is not defined
 //     at thrower
-//     at X.<anonymous>
+//     at X.<instance_fields_initializer>
 //     at new X
 //     at testClassInstantiation
 //     at testTrace
 testTrace(
   "during class instantiation with super",
   testClassInstantiationWithSuper,
-  ["thrower", "X.<anonymous>", "new X"],
-  ["Base"]
+  ["thrower", "X.<instance_fields_initializer>", "new X"],
+  ["Base", "anonymous"]
 );
 
 function testClassInstantiationWithSuper2() {
@@ -123,15 +124,15 @@ function testClassInstantiationWithSuper2() {
 
 // ReferenceError: FAIL is not defined
 //     at thrower
-//     at X.<anonymous>
+//     at X.<instance_fields_initializer>
 //     at new X
 //     at testClassInstantiation
 //     at testTrace
 testTrace(
   "during class instantiation with super2",
   testClassInstantiationWithSuper2,
-  ["thrower", "X.<anonymous>", "new X"],
-  ["Base"]
+  ["thrower", "X.<instance_fields_initializer>", "new X"],
+  ["Base", "anonymous"]
 );
 
 function testClassInstantiationWithSuper3() {
@@ -150,7 +151,7 @@ function testClassInstantiationWithSuper3() {
 
 // ReferenceError: FAIL is not defined
 //     at thrower
-//     at X.<anonymous>
+//     at X.<instance_fields_initializer>
 //     at new Base
 //     at new X
 //     at testClassInstantiationWithSuper3
@@ -158,7 +159,8 @@ function testClassInstantiationWithSuper3() {
 testTrace(
   "during class instantiation with super3",
   testClassInstantiationWithSuper3,
-  ["thrower", "X.<anonymous>", "new Base", "new X"]
+  ["thrower", "X.<instance_fields_initializer>", "new Base", "new X"],
+  ["anonymous"]
 );
 
 function testClassFieldCall() {