Changeset 69906 in webkit for trunk/JavaScriptCore/parser/JSParser.cpp

Timestamp:

Oct 15, 2010, 6:50:16 PM (15 years ago)

Author:

[email protected]

Message:

2010-10-15 Oliver Hunt <​[email protected]>

Reviewed by Sam Weinig.

Automatic Semicolon Insertion incorrectly inserts semicolon after break, continue, and return followed by a newline
​https://bugs.webkit.org/show_bug.cgi?id=47762

The old YACC parser depended on the lexer for some classes of semicolon insertion.
The new parser handles ASI entirely on its own so when the lexer inserts a semicolon
on its own the net result is a spurious semicolon in the input stream. This can result
in incorrect parsing in some cases:

if (0)

break

;else {}

Would result in a parse failure as the output from the lexer is essentially

if (0)

break

;;else

So the second semicolon is interpreted as a empty statement, which terminates the if,
making the else an error.

• parser/JSParser.cpp: (JSC::JSParser::parseThrowStatement): Parsing of throw statement was wrong, and only worked due to the weird behaviour in the lexer
• parser/Lexer.cpp: (JSC::Lexer::lex): Remove bogus semicolon insertion from the newline handling

2010-10-15 Oliver Hunt <​[email protected]>

Reviewed by Sam Weinig.

ASI incorrectly inserts semicolon after break, continue, and return followed by a newline
​https://bugs.webkit.org/show_bug.cgi?id=47762

tests for correct ASI following break, continue, and return

• fast/js/break-ASI-expected.txt: Added.
• fast/js/break-ASI.html: Added.
• fast/js/script-tests/break-ASI.js: Added.

File:

• trunk/JavaScriptCore/parser/JSParser.cpp (modified) (2 diffs)

trunk/JavaScriptCore/parser/JSParser.cpp

@@ -902 +902 @@
     int startLine = tokenLine();
     next();
+    
+    failIfTrue(autoSemiColon());
 
     TreeExpression expr = parseExpression(context);
@@ -907 +909 @@
     int eEnd = lastTokenEnd();
     int endLine = tokenLine();
-    failIfFalse(autoSemiColon());
 
     return context.createThrowStatement(expr, eStart, eEnd, startLine, endLine);