Added a test for SIL parsing/printing round-tripping, and fixed a bug.

Author: Mingsheng Hong

lib/ParseSIL/ParseSIL.cpp

@@ -2380,6 +2380,10 @@ bool SILParser::parseSILInstruction(SILBuilder &B) {
     // Drop the double quotes.
     StringRef rawString = P.Tok.getText().drop_front().drop_back();
 
+    P.consumeToken(tok::string_literal);
+    if (parseSILDebugLocation(InstLoc, B))
+      return true;
+
     // Ask the lexer to interpret the entire string as a literal segment.
     SmallVector<char, 128> stringBuffer;
 
@@ -2407,9 +2411,6 @@ bool SILParser::parseSILInstruction(SILBuilder &B) {
     }
 
     StringRef string = P.L->getEncodedStringSegment(rawString, stringBuffer);
-    P.consumeToken(tok::string_literal);
-    if (parseSILDebugLocation(InstLoc, B))
-      return true;
     ResultVal = B.createStringLiteral(InstLoc, string, encoding);
     break;
   }

test/SIL/Serialization/literals.sil

@@ -14,6 +14,8 @@ bb0:
   %2 = const_string_literal utf8 "\u{0B}"
 // CHECK: const_string_literal utf16 "\u{0B}"
   %3 = const_string_literal utf16 "\u{0B}"
+// CHECK: string_literal bytes "ABCD"
+  %4 = string_literal bytes "ABCD"
   %6 = tuple ()
   return %6 : $()
 }