Fix pre-parsing function declarations.

The preparser has been out of sync with the parser. As a reminder, we have the
following grammer for harmony mode

 Block ::
   { SourceElement* }
 SourceElement ::
   Statement
   FunctionDeclaration
   LetDeclaration

instead of

 Block ::
   { Statement* }
 SourceElement ::
   Statement
   FunctionDeclaration

The extension to allow FunctionDeclarations in statement positions in
non-strict code is still active.

Review URL: http://codereview.chromium.org/7983006

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@9363 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/parser.cc

@@ -1103,14 +1103,16 @@ class ThisNamedPropertyAssigmentFinder : public ParserFinder {
 
 Statement* Parser::ParseSourceElement(ZoneStringList* labels,
                                       bool* ok) {
+  // (Ecma 262 5th Edition, clause 14):
+  // SourceElement:
+  //    Statement
+  //    FunctionDeclaration
+  //
+  // In harmony mode we allow additionally the following productions
+  // SourceElement:
+  //    LetDeclaration
+
   if (peek() == Token::FUNCTION) {
-    // FunctionDeclaration is only allowed in the context of SourceElements
-    // (Ecma 262 5th Edition, clause 14):
-    // SourceElement:
-    //    Statement
-    //    FunctionDeclaration
-    // Common language extension is to allow function declaration in place
-    // of any statement. This language extension is disabled in strict mode.
     return ParseFunctionDeclaration(ok);
   } else if (peek() == Token::LET) {
     return ParseVariableStatement(kSourceElement, ok);
@@ -1124,7 +1126,7 @@ void* Parser::ParseSourceElements(ZoneList<Statement*>* processor,
                                   int end_token,
                                   bool* ok) {
   // SourceElements ::
-  //   (Statement)* <end_token>
+  //   (SourceElement)* <end_token>
 
   // Allocate a target stack to use for this set of source
   // elements. This way, all scripts and functions get their own
@@ -1295,8 +1297,13 @@ Statement* Parser::ParseStatement(ZoneStringList* labels, bool* ok) {
     }
 
     case Token::FUNCTION: {
-      // In strict mode, FunctionDeclaration is only allowed in the context
-      // of SourceElements.
+      // FunctionDeclaration is only allowed in the context of SourceElements
+      // (Ecma 262 5th Edition, clause 14):
+      // SourceElement:
+      //    Statement
+      //    FunctionDeclaration
+      // Common language extension is to allow function declaration in place
+      // of any statement. This language extension is disabled in strict mode.
       if (top_scope_->is_strict_mode()) {
         ReportMessageAt(scanner().peek_location(), "strict_function",
                         Vector<const char*>::empty());
@@ -1555,6 +1562,11 @@ Block* Parser::ParseBlock(ZoneStringList* labels, bool* ok) {
 
 
 Block* Parser::ParseScopedBlock(ZoneStringList* labels, bool* ok) {
+  // The harmony mode uses source elements instead of statements.
+  //
+  // Block ::
+  //   '{' SourceElement* '}'
+
   // Construct block expecting 16 statements.
   Block* body = new(zone()) Block(isolate(), labels, 16, false);
   Scope* saved_scope = top_scope_;

src/preparser.cc

@@ -117,7 +117,18 @@ void PreParser::CheckOctalLiteral(int beg_pos, int end_pos, bool* ok) {
 
 
 PreParser::Statement PreParser::ParseSourceElement(bool* ok) {
+  // (Ecma 262 5th Edition, clause 14):
+  // SourceElement:
+  //    Statement
+  //    FunctionDeclaration
+  //
+  // In harmony mode we allow additionally the following productions
+  // SourceElement:
+  //    LetDeclaration
+
   switch (peek()) {
+    case i::Token::FUNCTION:
+      return ParseFunctionDeclaration(ok);
     case i::Token::LET:
       return ParseVariableStatement(kSourceElement, ok);
     default:
@@ -225,8 +236,19 @@ PreParser::Statement PreParser::ParseStatement(bool* ok) {
     case i::Token::TRY:
       return ParseTryStatement(ok);
 
-    case i::Token::FUNCTION:
-      return ParseFunctionDeclaration(ok);
+    case i::Token::FUNCTION: {
+      i::Scanner::Location start_location = scanner_->peek_location();
+      Statement statement = ParseFunctionDeclaration(CHECK_OK);
+      i::Scanner::Location end_location = scanner_->location();
+      if (strict_mode()) {
+        ReportMessageAt(start_location.beg_pos, end_location.end_pos,
+                        "strict_function", NULL);
+        *ok = false;
+        return Statement::Default();
+      } else {
+        return statement;
+      }
+    }
 
     case i::Token::DEBUGGER:
       return ParseDebuggerStatement(ok);
@@ -271,14 +293,10 @@ PreParser::Statement PreParser::ParseBlock(bool* ok) {
   //
   Expect(i::Token::LBRACE, CHECK_OK);
   while (peek() != i::Token::RBRACE) {
-    i::Scanner::Location start_location = scanner_->peek_location();
-    Statement statement = ParseSourceElement(CHECK_OK);
-    i::Scanner::Location end_location = scanner_->location();
-    if (strict_mode() && statement.IsFunctionDeclaration()) {
-      ReportMessageAt(start_location.beg_pos, end_location.end_pos,
-                      "strict_function", NULL);
-      *ok = false;
-      return Statement::Default();
+    if (harmony_block_scoping_) {
+      ParseSourceElement(CHECK_OK);
+    } else {
+      ParseStatement(CHECK_OK);
     }
   }
   Expect(i::Token::RBRACE, ok);
@@ -375,15 +393,7 @@ PreParser::Statement PreParser::ParseExpressionOrLabelledStatement(bool* ok) {
     if (peek() == i::Token::COLON &&
         (!strict_mode() || !expr.AsIdentifier().IsFutureReserved())) {
       Consume(i::Token::COLON);
-      i::Scanner::Location start_location = scanner_->peek_location();
-      Statement statement = ParseStatement(CHECK_OK);
-      if (strict_mode() && statement.IsFunctionDeclaration()) {
-        i::Scanner::Location end_location = scanner_->location();
-        ReportMessageAt(start_location.beg_pos, end_location.end_pos,
-                        "strict_function", NULL);
-        *ok = false;
-      }
-      return Statement::Default();
+      return ParseStatement(ok);
     }
     // Preparsing is disabled for extensions (because the extension details
     // aren't passed to lazily compiled functions), so we don't
@@ -513,15 +523,7 @@ PreParser::Statement PreParser::ParseSwitchStatement(bool* ok) {
       Expect(i::Token::DEFAULT, CHECK_OK);
       Expect(i::Token::COLON, CHECK_OK);
     } else {
-      i::Scanner::Location start_location = scanner_->peek_location();
-      Statement statement = ParseStatement(CHECK_OK);
-      if (strict_mode() && statement.IsFunctionDeclaration()) {
-        i::Scanner::Location end_location = scanner_->location();
-        ReportMessageAt(start_location.beg_pos, end_location.end_pos,
-                        "strict_function", NULL);
-        *ok = false;
-        return Statement::Default();
-      }
+      ParseStatement(CHECK_OK);
     }
     token = peek();
   }

test/mjsunit/harmony/block-let-declaration.js

@@ -47,19 +47,70 @@ if (true) {
   assertEquals(undefined, y);
 }
 
+// Invalid declarations are early errors in harmony mode and thus should trigger
+// an exception in eval code during parsing, before even compiling or executing
+// the code. Thus the generated function is not called here.
 function TestLocalThrows(str, expect) {
-  assertThrows("(function(){" + str + "})()", expect);
+  assertThrows("(function(){" + str + "})", expect);
 }
 
 function TestLocalDoesNotThrow(str) {
   assertDoesNotThrow("(function(){" + str + "})()");
 }
 
-// Unprotected statement
+// Test let declarations statement positions.
 TestLocalThrows("if (true) let x;", SyntaxError);
+TestLocalThrows("if (true) {} else let x;", SyntaxError);
 TestLocalThrows("do let x; while (false)", SyntaxError);
 TestLocalThrows("while (false) let x;", SyntaxError);
+TestLocalThrows("label: let x;", SyntaxError);
+TestLocalThrows("for (;false;) let x;", SyntaxError);
+TestLocalThrows("switch (true) { case true: let x; }", SyntaxError);
+TestLocalThrows("switch (true) { default: let x; }", SyntaxError);
 
+// Test var declarations statement positions.
 TestLocalDoesNotThrow("if (true) var x;");
+TestLocalDoesNotThrow("if (true) {} else var x;");
 TestLocalDoesNotThrow("do var x; while (false)");
 TestLocalDoesNotThrow("while (false) var x;");
+TestLocalDoesNotThrow("label: var x;");
+TestLocalDoesNotThrow("for (;false;) var x;");
+TestLocalDoesNotThrow("switch (true) { case true: var x; }");
+TestLocalDoesNotThrow("switch (true) { default: var x; }");
+
+// Test function declarations in source element and
+// non-strict statement positions.
+function f() {
+  // Non-strict source element positions.
+  function g0() {
+    "use strict";
+    // Strict source element positions.
+    function h() { }
+    {
+      function h1() { }
+    }
+  }
+  {
+    function g1() { }
+  }
+  // Non-strict statement positions.
+  if (true) function g2() { }
+  if (true) {} else function g3() { }
+  do function g4() { } while (false)
+  while (false) function g5() { }
+  label: function g6() { }
+  for (;false;) function g7() { }
+  switch (true) { case true: function g8() { } }
+  switch (true) { default: function g9() { } }
+}
+f();
+
+// Test function declarations in statement position in strict mode.
+TestLocalThrows("function f() { 'use strict'; if (true) function g() {}", SyntaxError);
+TestLocalThrows("function f() { 'use strict'; if (true) {} else function g() {}", SyntaxError);
+TestLocalThrows("function f() { 'use strict'; do function g() {} while (false)", SyntaxError);
+TestLocalThrows("function f() { 'use strict'; while (false) function g() {}", SyntaxError);
+TestLocalThrows("function f() { 'use strict'; label: function g() {}", SyntaxError);
+TestLocalThrows("function f() { 'use strict'; for (;false;) function g() {}", SyntaxError);
+TestLocalThrows("function f() { 'use strict'; switch (true) { case true: function g() {} }", SyntaxError);
+TestLocalThrows("function f() { 'use strict'; switch (true) { default: function g() {} }", SyntaxError);