Make PreParser track valid left hand sides.

Notes:
- This makes PreParser produce invalid_lhs_in_assignment and
invalid_lhs_in_prefix_op. Other errors will follow as the corresponding funcs
move to ParserBase.
- PreParserExpression::IsStrictFunction and StrictFunction() are not needed any
more -> removed them.

R=rossberg@chromium.org
BUG=

Review URL: https://codereview.chromium.org/196343033

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@20125 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/preparser.cc

@@ -874,7 +874,7 @@ PreParser::Expression PreParser::ParseLeftHandSideExpression(bool* ok) {
         if (result.IsThis()) {
           result = Expression::ThisProperty();
         } else {
-          result = Expression::Default();
+          result = Expression::Property();
         }
         break;
       }
@@ -891,7 +891,7 @@ PreParser::Expression PreParser::ParseLeftHandSideExpression(bool* ok) {
         if (result.IsThis()) {
           result = Expression::ThisProperty();
         } else {
-          result = Expression::Default();
+          result = Expression::Property();
         }
         break;
       }
@@ -913,13 +913,17 @@ PreParser::Expression PreParser::ParseMemberWithNewPrefixesExpression(
   if (peek() == Token::NEW) {
     Consume(Token::NEW);
     ParseMemberWithNewPrefixesExpression(CHECK_OK);
+    Expression expression = Expression::Default();
     if (peek() == Token::LPAREN) {
       // NewExpression with arguments.
       ParseArguments(CHECK_OK);
-      // The expression can still continue with . or [ after the arguments.
+      // The expression can still continue with . or [ after the arguments. Here
+      // we need to transmit the "is valid left hand side" property of the
+      // expression.
+      expression =
           ParseMemberExpressionContinuation(Expression::Default(), CHECK_OK);
     }
-    return Expression::Default();
+    return expression;
   }
   // No 'new' keyword.
   return ParseMemberExpression(ok);
@@ -980,7 +984,7 @@ PreParser::Expression PreParser::ParseMemberExpressionContinuation(
         if (expression.IsThis()) {
           expression = Expression::ThisProperty();
         } else {
-          expression = Expression::Default();
+          expression = Expression::Property();
         }
         break;
       }
@@ -990,7 +994,7 @@ PreParser::Expression PreParser::ParseMemberExpressionContinuation(
         if (expression.IsThis()) {
           expression = Expression::ThisProperty();
         } else {
-          expression = Expression::Default();
+          expression = Expression::Property();
         }
         break;
       }
@@ -1102,7 +1106,6 @@ PreParser::Expression PreParser::ParseFunctionLiteral(
 
     int end_position = scanner()->location().end_pos;
     CheckOctalLiteral(start_position, end_position, CHECK_OK);
-    return Expression::StrictFunction();
   }
 
   return Expression::Default();

src/preparser.h

@@ -554,8 +554,8 @@ class PreParserExpression {
     return PreParserExpression(kThisPropertyExpression);
   }
 
-  static PreParserExpression StrictFunction() {
-    return PreParserExpression(kStrictFunctionExpression);
+  static PreParserExpression Property() {
+    return PreParserExpression(kPropertyExpression);
   }
 
   bool IsIdentifier() { return (code_ & kIdentifierFlag) != 0; }
@@ -576,7 +576,9 @@ class PreParserExpression {
 
   bool IsThisProperty() { return code_ == kThisPropertyExpression; }
 
-  bool IsStrictFunction() { return code_ == kStrictFunctionExpression; }
+  bool IsProperty() {
+    return code_ == kPropertyExpression || code_ == kThisPropertyExpression;
+  }
 
   // Dummy implementation for making expression->AsCall() work (see below).
   PreParserExpression* operator->() { return this; }
@@ -590,9 +592,11 @@ class PreParserExpression {
   void set_index(int index) {}  // For YieldExpressions
 
  private:
-  // First two/three bits are used as flags.
-  // Bit 0 and 1 represent identifiers or strings literals, and are
-  // mutually exclusive, but can both be absent.
+  // Least significant 2 bits are used as flags. Bits 0 and 1 represent
+  // identifiers or strings literals, and are mutually exclusive, but can both
+  // be absent. If the expression is an identifier or a string literal, the
+  // other bits describe the type (see PreParserIdentifier::Type and string
+  // literal constants below).
   enum {
     kUnknownExpression = 0,
     // Identifiers
@@ -604,10 +608,11 @@ class PreParserExpression {
     kUseStrictString = kStringLiteralFlag | 8,
     kStringLiteralMask = kUseStrictString,
 
-    // Below here applies if neither identifier nor string literal.
-    kThisExpression = 4,
-    kThisPropertyExpression = 8,
-    kStrictFunctionExpression = 12
+    // Below here applies if neither identifier nor string literal. Reserve the
+    // 2 least significant bits for flags.
+    kThisExpression = 1 << 2,
+    kThisPropertyExpression = 2 << 2,
+    kPropertyExpression = 3 << 2
   };
 
   explicit PreParserExpression(int expression_code) : code_(expression_code) {}
@@ -830,8 +835,7 @@ class PreParserTraits {
 
   // Determine whether the expression is a valid assignment left-hand side.
   static bool IsValidLeftHandSide(PreParserExpression expression) {
-    // TODO(marja): check properly; for now, leave it to parser.
-    return true;
+    return expression.IsIdentifier() || expression.IsProperty();
   }
 
   static PreParserExpression MarkExpressionAsLValue(

test/cctest/test-parsing.cc

@@ -2526,3 +2526,73 @@ TEST(StrictDelete) {
   RunParserSyncTest(strict_context_data, bad_statement_data, kError);
   RunParserSyncTest(sloppy_context_data, bad_statement_data, kError);
 }
+
+
+TEST(ErrorInvalidLeftHandSide) {
+  const char* assignment_context_data[][2] = {
+    // {"", " = 1;"},
+    // {"\"use strict\"; ", " = 1;"},
+    { NULL, NULL }
+  };
+
+  const char* prefix_context_data[][2] = {
+    {"++", ";"},
+    {"\"use strict\"; ++", ";"},
+    {NULL, NULL},
+  };
+
+  const char* postfix_context_data[][2] = {
+    {"", "++;"},
+    {"\"use strict\"; ", "++;"},
+    { NULL, NULL }
+  };
+
+  // Good left hand sides for assigment or prefix / postfix operations.
+  const char* good_statement_data[] = {
+    "foo",
+    "foo.bar",
+    "foo[bar]",
+    "foo()[bar]",
+    "foo().bar",
+    "this.foo",
+    "this[foo]",
+    "new foo()[bar]",
+    "new foo().bar",
+    NULL
+  };
+
+  // Bad left hand sides for assigment or prefix / postfix operations.
+  const char* bad_statement_data_common[] = {
+    "2",
+    "foo()",
+    "null",
+    "if",  // Unexpected token
+    "{x: 1}",  // Unexpected token
+    "this",
+    "\"bar\"",
+    "(foo + bar)",
+    "new new foo()[bar]",  // means: new (new foo()[bar])
+    "new new foo().bar",  // means: new (new foo()[bar])
+    NULL
+  };
+
+  // These are not okay for assignment, but okay for prefix / postix.
+  const char* bad_statement_data_for_assignment[] = {
+    "++foo",
+    "foo++",
+    "foo + bar",
+    NULL
+  };
+
+  RunParserSyncTest(assignment_context_data, good_statement_data, kSuccess);
+  RunParserSyncTest(assignment_context_data, bad_statement_data_common, kError);
+  RunParserSyncTest(assignment_context_data, bad_statement_data_for_assignment,
+                    kError);
+
+  RunParserSyncTest(prefix_context_data, good_statement_data, kSuccess);
+  RunParserSyncTest(prefix_context_data, bad_statement_data_common, kError);
+
+  RunParserSyncTest(postfix_context_data, good_statement_data, kSuccess);
+  // TODO(marja): This doesn't work yet.
+  // RunParserSyncTest(postfix_context_data, bad_statement_data_common, kError);
+}