Implement new Function.prototype.toString and fix CreateDynamicFunction parsing

src/parsing/parser-base.h

Index: src/parsing/parser-base.h
diff --git a/src/parsing/parser-base.h b/src/parsing/parser-base.h
index 35e103cdab8fd426783f6a6ff0cbdc35efc83b5e..2f0742b5cc9e4ce61e90027ae532d32ddbc0bcc4 100644
--- a/src/parsing/parser-base.h
+++ b/src/parsing/parser-base.h
@@ -2218,10 +2218,12 @@ ParserBase<Impl>::ParseClassPropertyDefinition(
 
   Token::Value name_token = peek();
 
+  int function_token_position = scanner()->peek_location().beg_pos;
   IdentifierT name = impl()->EmptyIdentifier();
   ExpressionT name_expression;
   if (name_token == Token::STATIC) {
     Consume(Token::STATIC);
+    function_token_position = scanner()->peek_location().beg_pos;
     if (peek() == Token::LPAREN) {
       kind = PropertyKind::kMethodProperty;
       name = impl()->GetSymbol();  // TODO(bakkot) specialize on 'static'
@@ -2298,8 +2300,10 @@ ParserBase<Impl>::ParseClassPropertyDefinition(
 
       ExpressionT value = impl()->ParseFunctionLiteral(
           name, scanner()->location(), kSkipFunctionNameCheck, kind,
-          kNoSourcePosition, FunctionLiteral::kAccessorOrMethod,
-          language_mode(), CHECK_OK_CUSTOM(EmptyClassLiteralProperty));
+          FLAG_harmony_function_tostring ? function_token_position
+                                         : kNoSourcePosition,
+          FunctionLiteral::kAccessorOrMethod, language_mode(),
+          CHECK_OK_CUSTOM(EmptyClassLiteralProperty));
 
       *property_kind = ClassLiteralProperty::METHOD;
       return factory()->NewClassLiteralProperty(name_expression, value,
@@ -2326,8 +2330,10 @@ ParserBase<Impl>::ParseClassPropertyDefinition(
 
       FunctionLiteralT value = impl()->ParseFunctionLiteral(
           name, scanner()->location(), kSkipFunctionNameCheck, kind,
-          kNoSourcePosition, FunctionLiteral::kAccessorOrMethod,
-          language_mode(), CHECK_OK_CUSTOM(EmptyClassLiteralProperty));
+          FLAG_harmony_function_tostring ? function_token_position
+                                         : kNoSourcePosition,
+          FunctionLiteral::kAccessorOrMethod, language_mode(),
+          CHECK_OK_CUSTOM(EmptyClassLiteralProperty));
 
       if (!*is_computed_name) {
         impl()->AddAccessorPrefixToFunctionName(is_get, value, name);
@@ -2522,8 +2528,9 @@ ParserBase<Impl>::ParseObjectPropertyDefinition(ObjectLiteralChecker* checker,
 
       ExpressionT value = impl()->ParseFunctionLiteral(
           name, scanner()->location(), kSkipFunctionNameCheck, kind,
-          kNoSourcePosition, FunctionLiteral::kAccessorOrMethod,
-          language_mode(), CHECK_OK_CUSTOM(EmptyObjectLiteralProperty));
+          FLAG_harmony_function_tostring ? next_beg_pos : kNoSourcePosition,
+          FunctionLiteral::kAccessorOrMethod, language_mode(),
+          CHECK_OK_CUSTOM(EmptyObjectLiteralProperty));
 
       return factory()->NewObjectLiteralProperty(
           name_expression, value, ObjectLiteralProperty::COMPUTED,
@@ -2551,8 +2558,9 @@ ParserBase<Impl>::ParseObjectPropertyDefinition(ObjectLiteralChecker* checker,
 
       FunctionLiteralT value = impl()->ParseFunctionLiteral(
           name, scanner()->location(), kSkipFunctionNameCheck, kind,
-          kNoSourcePosition, FunctionLiteral::kAccessorOrMethod,
-          language_mode(), CHECK_OK_CUSTOM(EmptyObjectLiteralProperty));
+          FLAG_harmony_function_tostring ? next_beg_pos : kNoSourcePosition,
+          FunctionLiteral::kAccessorOrMethod, language_mode(),
+          CHECK_OK_CUSTOM(EmptyObjectLiteralProperty));
 
       if (!*is_computed_name) {
         impl()->AddAccessorPrefixToFunctionName(is_get, value, name);
@@ -3417,7 +3425,12 @@ typename ParserBase<Impl>::ExpressionT ParserBase<Impl>::ParseMemberExpression(
     Scanner::Location function_name_location = Scanner::Location::invalid();
     FunctionLiteral::FunctionType function_type =
         FunctionLiteral::kAnonymousExpression;
-    if (peek_any_identifier()) {
+    if (impl()->ParsingDynamicFunctionDeclaration()) {
+      // Consume and discard the next token, which is always the identifier
+      // "anonymous".

[Dan Ehrenberg, 2017/02/14 12:06:00]

Optional: Instead of saying what this is doing (which is sort of apparent from
the next line), the comment could explain that it's doing this to avoid giving
the name "anonymous", because it's synthetic.

+      Consume(Token::IDENTIFIER);
+      DCHECK(scanner()->UnescapedLiteralMatches("anonymous", 9));
+    } else if (peek_any_identifier()) {
       name = ParseIdentifierOrStrictReservedWord(
           function_kind, &is_strict_reserved_name, CHECK_OK);
       function_name_location = scanner()->location();
@@ -4446,7 +4459,12 @@ ParserBase<Impl>::ParseAsyncFunctionLiteral(bool* ok) {
   IdentifierT name = impl()->EmptyIdentifier();
   FunctionLiteral::FunctionType type = FunctionLiteral::kAnonymousExpression;
 
-  if (peek_any_identifier()) {
+  if (impl()->ParsingDynamicFunctionDeclaration()) {
+    // Consume and discard the next token, which is always the identifier
+    // "anonymous".
+    Consume(Token::IDENTIFIER);
+    DCHECK(scanner()->UnescapedLiteralMatches("anonymous", 9));
+  } else if (peek_any_identifier()) {
     type = FunctionLiteral::kNamedExpression;
     name = ParseIdentifierOrStrictReservedWord(FunctionKind::kAsyncFunction,
                                                &is_strict_reserved, CHECK_OK);