Changeset 248826 in webkit for trunk/Source/JavaScriptCore/parser/Lexer.cpp

Timestamp:

Aug 17, 2019, 7:20:07 PM (6 years ago)

Author:

Ross Kirsling

Message:

[ESNext] Support hashbang.
​https://bugs.webkit.org/show_bug.cgi?id=200865

Reviewed by Mark Lam.

JSTests:

• stress/hashbang.js: Added.
• test262/expectations.yaml: Mark 6 cases as passing.

Source/JavaScriptCore:

Hashbang (a.k.a. shebang) support is at Stage 3 in TC39:
​https://github.com/tc39/proposal-hashbang

This allows #! to be treated like //, but only at the very start of the source text.

• parser/Lexer.cpp:

(JSC::Lexer<T>::Lexer):
(JSC::Lexer<T>::lexWithoutClearingLineTerminator):

File:

• trunk/Source/JavaScriptCore/parser/Lexer.cpp (modified) (4 diffs)

trunk/Source/JavaScriptCore/parser/Lexer.cpp

@@ -96 +96 @@
     // Other types (only one so far)
     CharacterWhiteSpace,
+    CharacterHash,
     CharacterPrivateIdentifierStart
 };
@@ -136 +137 @@
 /*  33 - !                  */ CharacterExclamationMark,
 /*  34 - "                  */ CharacterQuote,
-/*  35 - #                  */ CharacterInvalid,
+/*  35 - #                  */ CharacterHash,
 /*  36 - $                  */ CharacterIdentifierStart,
 /*  37 - %                  */ CharacterModulo,
@@ -2423 +2424 @@
         m_lineStart = m_code;
         goto start;
+    case CharacterHash:
+        // Hashbang is only permitted at the start of the source text.
+        if (peek(1) == '!' && !currentOffset()) {
+            shift();
+            shift();
+            goto inSingleLineComment;
+        }
+        goto invalidCharacter;
     case CharacterPrivateIdentifierStart:
         if (m_parsingBuiltinFunction)
             goto parseIdent;
-
-        FALLTHROUGH;
+        goto invalidCharacter;
     case CharacterOtherIdentifierPart:
     case CharacterInvalid:
-        m_lexErrorMessage = invalidCharacterMessage();
-        token = ERRORTOK;
-        goto returnError;
+        goto invalidCharacter;
     default:
         RELEASE_ASSERT_NOT_REACHED();
@@ -2482 +2488 @@
     fillTokenInfo(tokenRecord, token, m_lineNumber, currentOffset(), currentLineStartOffset(), currentPosition());
     return token;
+
+invalidCharacter:
+    m_lexErrorMessage = invalidCharacterMessage();
+    token = ERRORTOK;
+    // Falls through to return error.
 
 returnError: