Fix V8 bug 1084: allow "\0" in strict mode as valid escape sequence.

http://code.google.com/p/v8/issues/detail?id=1084

Code Review URL: http://codereview.chromium.org/6386014/

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@6550 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/scanner-base.cc

@@ -99,9 +99,9 @@ uc32 Scanner::ScanHexEscape(uc32 c, int length) {
 // Octal escapes of the forms '\0xx' and '\xxx' are not a part of
 // ECMA-262. Other JS VMs support them.
 uc32 Scanner::ScanOctalEscape(uc32 c, int length) {
-  octal_pos_ = source_pos() - 1;     // Already advanced
   uc32 x = c - '0';
-  for (int i = 0; i < length; i++) {
+  int i = 0;
+  for (; i < length; i++) {
     int d = c0_ - '0';
     if (d < 0 || d > 7) break;
     int nx = x * 8 + d;
@@ -109,6 +109,12 @@ uc32 Scanner::ScanOctalEscape(uc32 c, int length) {
     x = nx;
     Advance();
   }
+  // Anything excelt '\0' is an octal escape sequence, illegal in strict mode.
+  // Remember the position of octal escape sequences so that better error
+  // can be reported later (in strict mode).
+  if (c != '0' || i > 0) {
+    octal_pos_ = source_pos() - i - 1;     // Already advanced
+  }
   return x;
 }
 

src/scanner-base.h

@@ -409,6 +409,8 @@ class Scanner {
   }
 
   uc32 ScanHexEscape(uc32 c, int length);
+
+  // Scans octal escape sequence. Also accepts "\0" decimal escape sequence.
   uc32 ScanOctalEscape(uc32 c, int length);
 
   // Return the current source position.