Make invalid break/continue statements an early syntax error.

Previously we delayed the throwing of syntax errors until runtime, so
unreachable errors didn't get reported.
To match a change in JSC, we now stop parsing and report the error immediately.

BUG=69736
TEST=

Review URL: http://codereview.chromium.org/6355006

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@6341 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/parser.cc

@@ -778,7 +778,8 @@ void Parser::ReportMessageAt(Scanner::Location source_location,
                              const char* type,
                              Vector<const char*> args) {
   MessageLocation location(script_,
-                           source_location.beg_pos, source_location.end_pos);
+                           source_location.beg_pos,
+                           source_location.end_pos);
   Handle<JSArray> array = Factory::NewJSArray(args.length());
   for (int i = 0; i < args.length(); i++) {
     SetElement(array, i, Factory::NewStringFromUtf8(CStrVector(args[i])));
@@ -788,6 +789,21 @@ void Parser::ReportMessageAt(Scanner::Location source_location,
 }
 
 
+void Parser::ReportMessageAt(Scanner::Location source_location,
+                             const char* type,
+                             Vector<Handle<String> > args) {
+  MessageLocation location(script_,
+                           source_location.beg_pos,
+                           source_location.end_pos);
+  Handle<JSArray> array = Factory::NewJSArray(args.length());
+  for (int i = 0; i < args.length(); i++) {
+    SetElement(array, i, args[i]);
+  }
+  Handle<Object> result = Factory::NewSyntaxError(type, array);
+  Top::Throw(*result, &location);
+}
+
+
 // Base class containing common code for the different finder classes used by
 // the parser.
 class ParserFinder {
@@ -1693,12 +1709,16 @@ Statement* Parser::ParseContinueStatement(bool* ok) {
   IterationStatement* target = NULL;
   target = LookupContinueTarget(label, CHECK_OK);
   if (target == NULL) {
-    // Illegal continue statement.  To be consistent with KJS we delay
-    // reporting of the syntax error until runtime.
-    Handle<String> error_type = Factory::illegal_continue_symbol();
-    if (!label.is_null()) error_type = Factory::unknown_label_symbol();
-    Expression* throw_error = NewThrowSyntaxError(error_type, label);
-    return new ExpressionStatement(throw_error);
+    // Illegal continue statement.
+    const char* message = "illegal_continue";
+    Vector<Handle<String> > args;
+    if (!label.is_null()) {
+      message = "unknown_label";
+      args = Vector<Handle<String> >(&label, 1);
+    }
+    ReportMessageAt(scanner().location(), message, args);
+    *ok = false;
+    return NULL;
   }
   ExpectSemicolon(CHECK_OK);
   return new ContinueStatement(target);
@@ -1724,12 +1744,16 @@ Statement* Parser::ParseBreakStatement(ZoneStringList* labels, bool* ok) {
   BreakableStatement* target = NULL;
   target = LookupBreakTarget(label, CHECK_OK);
   if (target == NULL) {
-    // Illegal break statement.  To be consistent with KJS we delay
-    // reporting of the syntax error until runtime.
-    Handle<String> error_type = Factory::illegal_break_symbol();
-    if (!label.is_null()) error_type = Factory::unknown_label_symbol();
-    Expression* throw_error = NewThrowSyntaxError(error_type, label);
-    return new ExpressionStatement(throw_error);
+    // Illegal break statement.
+    const char* message = "illegal_break";
+    Vector<Handle<String> > args;
+    if (!label.is_null()) {
+      message = "unknown_label";
+      args = Vector<Handle<String> >(&label, 1);
+    }
+    ReportMessageAt(scanner().location(), message, args);
+    *ok = false;
+    return NULL;
   }
   ExpectSemicolon(CHECK_OK);
   return new BreakStatement(target);

src/parser.h

@@ -430,6 +430,9 @@ class Parser {
   void ReportMessageAt(Scanner::Location loc,
                        const char* message,
                        Vector<const char*> args);
+  void ReportMessageAt(Scanner::Location loc,
+                       const char* message,
+                       Vector<Handle<String> > args);
 
  protected:
   FunctionLiteral* ParseLazy(Handle<SharedFunctionInfo> info,

test/mjsunit/delay-syntax-error.js

@@ -25,17 +25,18 @@
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-// To be compatible with KJS syntax errors for illegal return, break
-// and continue should be delayed to runtime.
+// To be compatible with JSC syntax errors for illegal returns should be delayed
+// to runtime.
+// Invalid continue and break statements are caught at compile time.
 
-// Do not throw syntax errors for illegal return, break and continue
-// at compile time.
+// Do not throw syntax errors for illegal return at compile time.
 assertDoesNotThrow("if (false) return;");
-assertDoesNotThrow("if (false) break;");
-assertDoesNotThrow("if (false) continue;");
 
-// Throw syntax errors for illegal return, break and continue at
-// compile time.
+// Throw syntax errors for illegal break and continue at compile time.
+assertThrows("if (false) break;");
+assertThrows("if (false) continue;");
+
+// Throw syntax errors for illegal return, break and continue at runtime.
 assertThrows("return;");
 assertThrows("break;");
 assertThrows("continue;");

test/mjsunit/regress/regress-1036894.js

@@ -25,14 +25,14 @@
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-xeval = function(s) { eval(s); }
-xeval("$=function anonymous() { /*noex*/do {} while(({ get x(x) { break ; }, set x() { (undefined);} })); }");
+assertThrows("$=function anonymous() { /*noex*/do {} while(({ get x(x) { break ; }, set x() { (undefined);} })); }");
 
-foo = function() { eval("$=function anonymous() { /*noex*/do {} while(({ get x(x) { break ; }, set x() { (undefined);} })); }"); }
+function foo() {
+  assertThrows("$=function anonymous() { /*noex*/do {} while(({ get x(x) { break ; }, set x() { (undefined);} })); }");
+}
 foo();
 
-xeval = function(s) { eval(s); }
-eval("$=function anonymous() { /*noex*/do {} while(({ get x(x) { break ; }, set x() { (undefined);} })); }");
+assertThrows("$=function anonymous() { /*noex*/do {} while(({ get x(x) { break ; }, set x() { (undefined);} })); }");
 
 xeval = function(s) { eval(s); }
 xeval('$=function(){L: {break L;break L;}};');

test/mjsunit/regress/regress-990205.js

@@ -25,11 +25,15 @@
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
+// We throw syntax errors early for invalid break and continue statements.
+// (Notice that the example isn't valid ECMAScript due to the
+// function declaration that is not at top level.)
+
 function f() {
   // Force eager compilation of x through the use of eval. The break
   // in function x should not try to break out of the enclosing while.
   return eval("while(0) function x() { break; }; 42");
 };
 
-assertEquals(42, f());
+assertThrows("f()");