[strong] deprecate empty sub-statements

src/preparser.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <cmath>
 
 #include "src/allocation.h"
 #include "src/base/logging.h"
 #include "src/conversions-inl.h"
 #include "src/conversions.h"
@@ skipping 210 matching lines @@
 
 #define CHECK_OK  ok);                   \
   if (!*ok) return Statement::Default();  \
   ((void)0
 #define DUMMY )  // to make indentation work
 #undef DUMMY
 
 
 PreParser::Statement PreParser::ParseStatement(bool* ok) {
   // Statement ::
+  //   EmptyStatement
+  //   ...
+  return ParseSubStatement(ok);
+}
+
+
+PreParser::Statement PreParser::ParseSubStatement(bool* ok) {
+  // Statement ::
   //   Block
   //   VariableStatement
   //   EmptyStatement
   //   ExpressionStatement
   //   IfStatement
   //   IterationStatement
   //   ContinueStatement
   //   BreakStatement
   //   ReturnStatement
   //   WithStatement
   //   LabelledStatement
   //   SwitchStatement
   //   ThrowStatement
   //   TryStatement
   //   DebuggerStatement
 
   // Note: Since labels can only be used by 'break' and 'continue'
   // statements, which themselves are only valid within blocks,
   // iterations or 'switch' statements (i.e., BreakableStatements),
   // labels can be simply ignored in all other cases; except for
   // trivial labeled break statements 'label: break label' which is
   // parsed into an empty statement.
 
   // Keep the source position of the statement
   switch (peek()) {
     case Token::LBRACE:
       return ParseBlock(ok);
 
     case Token::SEMICOLON:
+      if (is_strong(language_mode())) {
+        PreParserTraits::ReportMessageAt(scanner()->peek_location(),
+                                         "strong_empty");
+        *ok = false;
+        return Statement::Default();
+      }
       Next();
       return Statement::Default();
 
     case Token::IF:
       return ParseIfStatement(ok);
 
     case Token::DO:
       return ParseDoWhileStatement(ok);
 
     case Token::WHILE:
@@ skipping 273 matching lines @@
 
 
 PreParser::Statement PreParser::ParseIfStatement(bool* ok) {
   // IfStatement ::
   //   'if' '(' Expression ')' Statement ('else' Statement)?
 
   Expect(Token::IF, CHECK_OK);
   Expect(Token::LPAREN, CHECK_OK);
   ParseExpression(true, CHECK_OK);
   Expect(Token::RPAREN, CHECK_OK);
-  ParseStatement(CHECK_OK);
+  ParseSubStatement(CHECK_OK);
   if (peek() == Token::ELSE) {
     Next();
-    ParseStatement(CHECK_OK);
+    ParseSubStatement(CHECK_OK);
   }
   return Statement::Default();
 }
 
 
 PreParser::Statement PreParser::ParseContinueStatement(bool* ok) {
   // ContinueStatement ::
   //   'continue' [no line terminator] Identifier? ';'
 
   Expect(Token::CONTINUE, CHECK_OK);
@@ skipping 62 matching lines @@
     ReportMessageAt(scanner()->location(), "strict_mode_with");
     *ok = false;
     return Statement::Default();
   }
   Expect(Token::LPAREN, CHECK_OK);
   ParseExpression(true, CHECK_OK);
   Expect(Token::RPAREN, CHECK_OK);
 
   Scope* with_scope = NewScope(scope_, WITH_SCOPE);
   BlockState block_state(&scope_, with_scope);
-  ParseStatement(CHECK_OK);
+  ParseSubStatement(CHECK_OK);
   return Statement::Default();
 }
 
 
 PreParser::Statement PreParser::ParseSwitchStatement(bool* ok) {
   // SwitchStatement ::
   //   'switch' '(' Expression ')' '{' CaseClause* '}'
 
   Expect(Token::SWITCH, CHECK_OK);
   Expect(Token::LPAREN, CHECK_OK);
@@ skipping 21 matching lines @@
   Expect(Token::RBRACE, ok);
   return Statement::Default();
 }
 
 
 PreParser::Statement PreParser::ParseDoWhileStatement(bool* ok) {
   // DoStatement ::
   //   'do' Statement 'while' '(' Expression ')' ';'
 
   Expect(Token::DO, CHECK_OK);
-  ParseStatement(CHECK_OK);
+  ParseSubStatement(CHECK_OK);
   Expect(Token::WHILE, CHECK_OK);
   Expect(Token::LPAREN, CHECK_OK);
   ParseExpression(true, CHECK_OK);
   Expect(Token::RPAREN, ok);
   if (peek() == Token::SEMICOLON) Consume(Token::SEMICOLON);
   return Statement::Default();
 }
 
 
 PreParser::Statement PreParser::ParseWhileStatement(bool* ok) {
   // WhileStatement ::
   //   'while' '(' Expression ')' Statement
 
   Expect(Token::WHILE, CHECK_OK);
   Expect(Token::LPAREN, CHECK_OK);
   ParseExpression(true, CHECK_OK);
   Expect(Token::RPAREN, CHECK_OK);
-  ParseStatement(ok);
+  ParseSubStatement(ok);
   return Statement::Default();
 }
 
 
 bool PreParser::CheckInOrOf(bool accept_OF) {
   if (Check(Token::IN) ||
       (accept_OF && CheckContextualKeyword(CStrVector("of")))) {
     return true;
   }
   return false;
@@ skipping 16 matching lines @@
       VariableDeclarationProperties decl_props = kHasNoInitializers;
       ParseVariableDeclarations(
           kForStatement, &decl_props, &decl_count, CHECK_OK);
       bool has_initializers = decl_props == kHasInitializers;
       bool accept_IN = decl_count == 1 && !(is_lexical && has_initializers);
       bool accept_OF = !has_initializers;
       if (accept_IN && CheckInOrOf(accept_OF)) {
         ParseExpression(true, CHECK_OK);
         Expect(Token::RPAREN, CHECK_OK);
 
-        ParseStatement(CHECK_OK);
+        ParseSubStatement(CHECK_OK);
         return Statement::Default();
       }
     } else {
       Expression lhs = ParseExpression(false, CHECK_OK);
       is_let_identifier_expression =
           lhs.IsIdentifier() && lhs.AsIdentifier().IsLet();
       if (CheckInOrOf(lhs.IsIdentifier())) {
         ParseExpression(true, CHECK_OK);
         Expect(Token::RPAREN, CHECK_OK);
 
-        ParseStatement(CHECK_OK);
+        ParseSubStatement(CHECK_OK);
         return Statement::Default();
       }
     }
   }
 
   // Parsed initializer at this point.
   // Detect attempts at 'let' declarations in sloppy mode.
   if (peek() == Token::IDENTIFIER && is_sloppy(language_mode()) &&
       is_let_identifier_expression) {
     ReportMessage("sloppy_lexical", NULL);
     *ok = false;
     return Statement::Default();
   }
   Expect(Token::SEMICOLON, CHECK_OK);
 
   if (peek() != Token::SEMICOLON) {
     ParseExpression(true, CHECK_OK);
   }
   Expect(Token::SEMICOLON, CHECK_OK);
 
   if (peek() != Token::RPAREN) {
     ParseExpression(true, CHECK_OK);
   }
   Expect(Token::RPAREN, CHECK_OK);
 
-  ParseStatement(ok);
+  ParseSubStatement(ok);
   return Statement::Default();
 }
 
 
 PreParser::Statement PreParser::ParseThrowStatement(bool* ok) {
   // ThrowStatement ::
   //   'throw' [no line terminator] Expression ';'
 
   Expect(Token::THROW, CHECK_OK);
   if (scanner()->HasAnyLineTerminatorBeforeNext()) {
@@ skipping 241 matching lines @@
   ParseIdentifier(kAllowEvalOrArguments, CHECK_OK);
   ParseArguments(ok);
 
   return Expression::Default();
 }
 
 #undef CHECK_OK
 
 
 } }  // v8::internal