libSyntax: create separate node kinds for quote (") and multiline quote (""").

This allows us to serialize the quote tokens without serializing their
underlying text.

Author: nkcsgexi

include/swift/Syntax/Serialization/SyntaxSerialization.h

@@ -155,7 +155,6 @@ struct ObjectTraits<TokenDescription> {
       case tok::oper_prefix:
       case tok::dollarident:
       case tok::comment:
-      case tok::string_quote:
       case tok::string_segment:
         out.mapRequired("text", value.Text);
         break;

include/swift/Syntax/TokenKinds.def

@@ -288,6 +288,7 @@ MISC(comment)
 MISC(string_interpolation_anchor)
 MISC(contextual_keyword)
 MISC(string_quote)
+MISC(multiline_string_quote)
 MISC(string_segment)
 
 #undef KEYWORD

lib/Parse/ParseExpr.cpp

@@ -2000,11 +2000,15 @@ ParserResult<Expr> Parser::parseExprStringLiteral() {
 
   // We are now sure this is a string interpolation expression.
   LocalContext.setCreateSyntax(SyntaxKind::StringInterpolationExpr);
-  StringRef Quote = Tok.IsMultilineString() ? "\"\"\"" : "\"";
+  StringRef Quote;
+  tok QuoteKind;
+  std::tie(Quote, QuoteKind) = Tok.IsMultilineString() ?
+    std::make_tuple("\"\"\"", tok::multiline_string_quote) :
+    std::make_tuple("\"", tok::string_quote);
 
   // Make unknown tokens to represent the open and close quote.
-  Token OpenQuote(tok::string_quote, Quote);
-  Token CloseQuote(tok::string_quote, Quote);
+  Token OpenQuote(QuoteKind, Quote);
+  Token CloseQuote(QuoteKind, Quote);
   Trivia EmptyTrivia;
   Trivia EntireTrailingTrivia = TrailingTrivia;
 

lib/Syntax/RawTokenSyntax.cpp

@@ -79,6 +79,9 @@ void RawTokenSyntax::dumpKind(llvm::raw_ostream &OS) const {
   case tok::string_quote:
     OS << "string_quote";
     break;
+  case tok::multiline_string_quote:
+    OS << "multiline_string_quote";
+    break;
   case tok::string_segment:
     OS << "string_segment";
     break;

utils/gyb_syntax_support/ExprNodes.py

@@ -430,8 +430,16 @@
     # e.g. "abc \(foo()) def"
     Node('StringInterpolationExpr', kind='Expr',
          children=[
-             Child('OpenQuote', kind='StringQuoteToken'),
+             Child('OpenQuote', kind='Token',
+                   token_choices=[
+                       'StringQuoteToken',
+                       'MultilineStringQuoteToken',
+                   ]),
              Child('Segments', kind='StringInterpolationSegments'),
-             Child('CloseQuote', kind='StringQuoteToken'),
+             Child('CloseQuote', kind='Token',
+                   token_choices=[
+                       'StringQuoteToken',
+                       'MultilineStringQuoteToken',
+                   ]),
          ]),
 ]

utils/gyb_syntax_support/Token.py

@@ -135,7 +135,9 @@ def __init__(self, name, text):
     Token('Backslash', 'backslash', text='\\\\'),
     Token('StringInterpolationAnchor', 'string_interpolation_anchor',
           text=')'),
-    Token('StringQuote', 'string_quote'),
+    Token('StringQuote', 'string_quote', text='\\\"'),
+    Token('MultilineStringQuote', 'multiline_string_quote',
+          text='\\\"\\\"\\\"'),
     Token('StringSegment', 'string_segment'),
     Token('Identifier', 'identifier'),
     Token('DollarIdentifier', 'dollarident'),