Merge bleeding edge up to 9192 into the GC branch.

src/parser.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 12 matching lines @@
 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 #include "v8.h"
 
 #include "api.h"
 #include "ast-inl.h"
 #include "bootstrapper.h"
+#include "char-predicates-inl.h"
 #include "codegen.h"
 #include "compiler.h"
 #include "func-name-inferrer.h"
 #include "messages.h"
 #include "parser.h"
 #include "platform.h"
 #include "preparser.h"
 #include "runtime.h"
 #include "scopeinfo.h"
 #include "string-stream.h"
@@ skipping 482 matching lines @@
     only_simple_this_property_assignments_(false),
     this_property_assignments_(isolate->factory()->empty_fixed_array()),
     parser_(parser),
     lexical_scope_parent_(parser->lexical_scope_),
     previous_scope_(parser->top_scope_),
     previous_with_nesting_level_(parser->with_nesting_level_),
     previous_ast_node_id_(isolate->ast_node_id()) {
   parser->top_scope_ = scope;
   parser->lexical_scope_ = this;
   parser->with_nesting_level_ = 0;
-  isolate->set_ast_node_id(AstNode::kFunctionEntryId + 1);
+  isolate->set_ast_node_id(AstNode::kDeclarationsId + 1);
 }
 
 
 LexicalScope::~LexicalScope() {
   parser_->top_scope_ = previous_scope_;
   parser_->lexical_scope_ = lexical_scope_parent_;
   parser_->with_nesting_level_ = previous_with_nesting_level_;
   parser_->isolate()->set_ast_node_id(previous_ast_node_id_);
 }
 
@@ skipping 94 matching lines @@
     if (strict_mode == kStrictMode) {
       top_scope_->EnableStrictMode();
     }
     ZoneList<Statement*>* body = new(zone()) ZoneList<Statement*>(16);
     bool ok = true;
     int beg_loc = scanner().location().beg_pos;
     ParseSourceElements(body, Token::EOS, &ok);
     if (ok && top_scope_->is_strict_mode()) {
       CheckOctalLiteral(beg_loc, scanner().location().end_pos, &ok);
     }
+
+    if (ok && harmony_block_scoping_) {
+      CheckConflictingVarDeclarations(scope, &ok);
+    }
+
     if (ok) {
       result = new(zone()) FunctionLiteral(
           isolate(),
           no_name,
           top_scope_,
           body,
           lexical_scope.materialized_literal_count(),
           lexical_scope.expected_property_count(),
           lexical_scope.only_simple_this_property_assignments(),
           lexical_scope.this_property_assignments(),
@@ skipping 676 matching lines @@
       : top_scope_->DeclarationScope();
   if (declaration_scope->is_function_scope() ||
       declaration_scope->is_strict_mode_eval_scope() ||
       declaration_scope->is_block_scope()) {
     // Declare the variable in the function scope.
     var = declaration_scope->LocalLookup(name);
     if (var == NULL) {
       // Declare the name.
       var = declaration_scope->DeclareLocal(name, mode);
     } else {
-      // The name was declared before; check for conflicting re-declarations.
-      // We have a conflict if either of the declarations is not a var. There
-      // is similar code in runtime.cc in the Declare functions.
+      // The name was declared in this scope before; check for conflicting
+      // re-declarations. We have a conflict if either of the declarations is
+      // not a var. There is similar code in runtime.cc in the Declare
+      // functions. The function CheckNonConflictingScope checks for conflicting
+      // var and let bindings from different scopes whereas this is a check for
+      // conflicting declarations within the same scope. This check also covers
+      //
+      // function () { let x; { var x; } }
+      //
+      // because the var declaration is hoisted to the function scope where 'x'
+      // is already bound.
       if ((mode != Variable::VAR) || (var->mode() != Variable::VAR)) {
         // We only have vars, consts and lets in declarations.
         ASSERT(var->mode() == Variable::VAR ||
                var->mode() == Variable::CONST ||
                var->mode() == Variable::LET);
+        if (harmony_block_scoping_) {
+          // In harmony mode we treat re-declarations as early errors. See
+          // ES5 16 for a definition of early errors.
+          SmartPointer<char> c_string = name->ToCString(DISALLOW_NULLS);
+          const char* elms[2] = { "Variable", *c_string };
+          Vector<const char*> args(elms, 2);
+          ReportMessage("redeclaration", args);
+          *ok = false;
+          return NULL;
+        }
         const char* type = (var->mode() == Variable::VAR) ? "var" :
                            (var->mode() == Variable::CONST) ? "const" : "let";
         Handle<String> type_string =
             isolate()->factory()->NewStringFromUtf8(CStrVector(type), TENURED);
         Expression* expression =
             NewThrowTypeError(isolate()->factory()->redeclaration_symbol(),
                               type_string, name);
         declaration_scope->SetIllegalRedeclaration(expression);
       }
     }
   }
 
   // We add a declaration node for every declaration. The compiler
   // will only generate code if necessary. In particular, declarations
   // for inner local variables that do not represent functions won't
   // result in any generated code.
   //
   // Note that we always add an unresolved proxy even if it's not
   // used, simply because we don't know in this method (w/o extra
   // parameters) if the proxy is needed or not. The proxy will be
   // bound during variable resolution time unless it was pre-bound
   // below.
   //
   // WARNING: This will lead to multiple declaration nodes for the
   // same variable if it is declared several times. This is not a
   // semantic issue as long as we keep the source order, but it may be
   // a performance issue since it may lead to repeated
   // Runtime::DeclareContextSlot() calls.
-  VariableProxy* proxy = declaration_scope->NewUnresolved(name, false);
-  declaration_scope->AddDeclaration(new(zone()) Declaration(proxy, mode, fun));
+  VariableProxy* proxy = declaration_scope->NewUnresolved(
+      name, false, scanner().location().beg_pos);
+  declaration_scope->AddDeclaration(
+      new(zone()) Declaration(proxy, mode, fun, top_scope_));
 
   // For global const variables we bind the proxy to a variable.
   if (mode == Variable::CONST && declaration_scope->is_global_scope()) {
     ASSERT(resolve);  // should be set by all callers
     Variable::Kind kind = Variable::NORMAL;
     var = new(zone()) Variable(declaration_scope,
                                name,
                                Variable::CONST,
                                true,
                                kind);
@@ skipping 133 matching lines @@
 }
 
 
 Block* Parser::ParseScopedBlock(ZoneStringList* labels, bool* ok) {
   // Construct block expecting 16 statements.
   Block* body = new(zone()) Block(isolate(), labels, 16, false);
   Scope* saved_scope = top_scope_;
   Scope* block_scope = NewScope(top_scope_,
                                 Scope::BLOCK_SCOPE,
                                 inside_with());
-  body->set_block_scope(block_scope);
-  block_scope->DeclareLocal(isolate()->factory()->block_scope_symbol(),
-                            Variable::VAR);
   if (top_scope_->is_strict_mode()) {
     block_scope->EnableStrictMode();
   }
   top_scope_ = block_scope;
 
   // Parse the statements and collect escaping labels.
   TargetCollector collector;
   Target target(&this->target_stack_, &collector);
   Expect(Token::LBRACE, CHECK_OK);
   {
     Target target_body(&this->target_stack_, body);
     InitializationBlockFinder block_finder(top_scope_, target_stack_);
 
     while (peek() != Token::RBRACE) {
       Statement* stat = ParseSourceElement(NULL, CHECK_OK);
       if (stat && !stat->IsEmpty()) {
         body->AddStatement(stat);
         block_finder.Update(stat);
       }
     }
   }
   Expect(Token::RBRACE, CHECK_OK);
-
-  // Create exit block.
-  Block* exit = new(zone()) Block(isolate(), NULL, 1, false);
-  exit->AddStatement(new(zone()) ExitContextStatement());
-
-  // Create a try-finally statement.
-  TryFinallyStatement* try_finally =
-      new(zone()) TryFinallyStatement(body, exit);
-  try_finally->set_escaping_targets(collector.targets());
   top_scope_ = saved_scope;
 
-  // Create a result block.
-  Block* result = new(zone()) Block(isolate(), NULL, 1, false);
-  result->AddStatement(try_finally);
-  return result;
+  block_scope = block_scope->FinalizeBlockScope();
+  body->set_block_scope(block_scope);
+  return body;
 }
 
 
 Block* Parser::ParseVariableStatement(VariableDeclarationContext var_context,
                                       bool* ok) {
   // VariableStatement ::
   //   VariableDeclarations ';'
 
   Handle<String> ignore;
   Block* result = ParseVariableDeclarations(var_context,
@@ skipping 15 matching lines @@
 // *var is untouched; in particular, it is the caller's responsibility
 // to initialize it properly. This mechanism is used for the parsing
 // of 'for-in' loops.
 Block* Parser::ParseVariableDeclarations(VariableDeclarationContext var_context,
                                          Handle<String>* out,
                                          bool* ok) {
   // VariableDeclarations ::
   //   ('var' | 'const') (Identifier ('=' AssignmentExpression)?)+[',']
 
   Variable::Mode mode = Variable::VAR;
+  // True if the binding needs initialization. 'let' and 'const' declared
+  // bindings are created uninitialized by their declaration nodes and
+  // need initialization. 'var' declared bindings are always initialized
+  // immediately by their declaration nodes.
+  bool needs_init = false;
   bool is_const = false;
+  Token::Value init_op = Token::INIT_VAR;
   if (peek() == Token::VAR) {
     Consume(Token::VAR);
   } else if (peek() == Token::CONST) {
     Consume(Token::CONST);
     if (top_scope_->is_strict_mode()) {
       ReportMessage("strict_const", Vector<const char*>::empty());
       *ok = false;
       return NULL;
     }
     mode = Variable::CONST;
     is_const = true;
+    needs_init = true;
+    init_op = Token::INIT_CONST;
   } else if (peek() == Token::LET) {
     Consume(Token::LET);
     if (var_context != kSourceElement &&
         var_context != kForStatement) {
       ASSERT(var_context == kStatement);
       ReportMessage("unprotected_let", Vector<const char*>::empty());
       *ok = false;
       return NULL;
     }
     mode = Variable::LET;
+    needs_init = true;
+    init_op = Token::INIT_LET;
   } else {
     UNREACHABLE();  // by current callers
   }
 
   Scope* declaration_scope = mode == Variable::LET
       ? top_scope_ : top_scope_->DeclarationScope();
   // The scope of a var/const declared variable anywhere inside a function
   // is the entire function (ECMA-262, 3rd, 10.1.3, and 12.2). Thus we can
   // transform a source-level var/const declaration into a (Function)
   // Scope declaration, and rewrite the source-level initialization into an
@@ skipping 81 matching lines @@
       position = scanner().location().beg_pos;
       value = ParseAssignmentExpression(var_context != kForStatement, CHECK_OK);
       // Don't infer if it is "a = function(){...}();"-like expression.
       if (fni_ != NULL &&
           value->AsCall() == NULL &&
           value->AsCallNew() == NULL) {
         fni_->Infer();
       }
     }
 
-    // Make sure that 'const c' actually initializes 'c' to undefined
-    // even though it seems like a stupid thing to do.
-    if (value == NULL && is_const) {
+    // Make sure that 'const x' and 'let x' initialize 'x' to undefined.
+    if (value == NULL && needs_init) {
       value = GetLiteralUndefined();
     }
 
     // Global variable declarations must be compiled in a specific
     // way. When the script containing the global variable declaration
     // is entered, the global variable must be declared, so that if it
     // doesn't exist (not even in a prototype of the global object) it
     // gets created with an initial undefined value. This is handled
     // by the declarations part of the function representing the
     // top-level global code; see Runtime::DeclareGlobalVariable. If
@@ skipping 56 matching lines @@
             new(zone()) CallRuntime(
                 isolate(),
                 isolate()->factory()->InitializeVarGlobal_symbol(),
                 Runtime::FunctionForId(Runtime::kInitializeVarGlobal),
                 arguments);
       }
 
       block->AddStatement(new(zone()) ExpressionStatement(initialize));
     }
 
-    // Add an assignment node to the initialization statement block if
-    // we still have a pending initialization value. We must distinguish
-    // between variables and constants: Variable initializations are simply
+    // Add an assignment node to the initialization statement block if we still
+    // have a pending initialization value. We must distinguish between
+    // different kinds of declarations: 'var' initializations are simply
     // assignments (with all the consequences if they are inside a 'with'
     // statement - they may change a 'with' object property). Constant
     // initializations always assign to the declared constant which is
     // always at the function scope level. This is only relevant for
     // dynamically looked-up variables and constants (the start context
     // for constant lookups is always the function context, while it is
-    // the top context for variables). Sigh...
+    // the top context for var declared variables). Sigh...
+    // For 'let' declared variables the initialization is in the same scope
+    // as the declaration. Thus dynamic lookups are unnecessary even if the
+    // block scope is inside a with.
     if (value != NULL) {
-      Token::Value op = (is_const ? Token::INIT_CONST : Token::INIT_VAR);
-      bool in_with = is_const ? false : inside_with();
+      bool in_with = mode == Variable::VAR ? inside_with() : false;
       VariableProxy* proxy =
           initialization_scope->NewUnresolved(name, in_with);
       Assignment* assignment =
-          new(zone()) Assignment(isolate(), op, proxy, value, position);
+          new(zone()) Assignment(isolate(), init_op, proxy, value, position);
       if (block) {
         block->AddStatement(new(zone()) ExpressionStatement(assignment));
       }
     }
 
     if (fni_ != NULL) fni_->Leave();
   } while (peek() == Token::COMMA);
 
   // If there was a single non-const declaration, return it in the output
   // parameter for possible use by for/in.
@@ skipping 344 matching lines @@
 
     if (top_scope_->is_strict_mode() && IsEvalOrArguments(name)) {
       ReportMessage("strict_catch_variable", Vector<const char*>::empty());
       *ok = false;
       return NULL;
     }
 
     Expect(Token::RPAREN, CHECK_OK);
 
     if (peek() == Token::LBRACE) {
-      // Rewrite the catch body { B } to a block:
-      // { { B } ExitContext; }.
       Target target(&this->target_stack_, &catch_collector);
       catch_scope = NewScope(top_scope_, Scope::CATCH_SCOPE, inside_with());
       if (top_scope_->is_strict_mode()) {
         catch_scope->EnableStrictMode();
       }
-      catch_variable = catch_scope->DeclareLocal(name, Variable::VAR);
-      catch_block = new(zone()) Block(isolate(), NULL, 2, false);
+      Variable::Mode mode = harmony_block_scoping_
+          ? Variable::LET : Variable::VAR;
+      catch_variable = catch_scope->DeclareLocal(name, mode);
 
       Scope* saved_scope = top_scope_;
       top_scope_ = catch_scope;
-      Block* catch_body = ParseBlock(NULL, CHECK_OK);
+      catch_block = ParseBlock(NULL, CHECK_OK);
       top_scope_ = saved_scope;
-      catch_block->AddStatement(catch_body);
-      catch_block->AddStatement(new(zone()) ExitContextStatement());
     } else {
       Expect(Token::LBRACE, CHECK_OK);
     }
 
     tok = peek();
   }
 
   Block* finally_block = NULL;
   if (tok == Token::FINALLY || catch_block == NULL) {
     Consume(Token::FINALLY);
@@ skipping 1500 matching lines @@
         name_loc = scanner().location();
       }
       if (!dupe_loc.IsValid() && top_scope_->IsDeclared(param_name)) {
         has_duplicate_parameters = true;
         dupe_loc = scanner().location();
       }
       if (!reserved_loc.IsValid() && is_strict_reserved) {
         reserved_loc = scanner().location();
       }
 
-      top_scope_->DeclareParameter(param_name);
+      top_scope_->DeclareParameter(param_name,
+                                   harmony_block_scoping_
+                                   ? Variable::LET
+                                   : Variable::VAR);
       num_parameters++;
       if (num_parameters > kMaxNumFunctionParameters) {
         ReportMessageAt(scanner().location(), "too_many_parameters",
                         Vector<const char*>::empty());
         *ok = false;
         return NULL;
       }
       done = (peek() == Token::RPAREN);
       if (!done) Expect(Token::COMMA, CHECK_OK);
     }
@@ skipping 106 matching lines @@
       if (reserved_loc.IsValid()) {
         ReportMessageAt(reserved_loc, "strict_reserved_word",
                         Vector<const char*>::empty());
         *ok = false;
         return NULL;
       }
       CheckOctalLiteral(start_pos, end_pos, CHECK_OK);
     }
   }
 
+  if (harmony_block_scoping_) {
+    CheckConflictingVarDeclarations(scope, CHECK_OK);
+  }
+
   FunctionLiteral* function_literal =
       new(zone()) FunctionLiteral(isolate(),
                                   function_name,
                                   scope,
                                   body,
                                   materialized_literal_count,
                                   expected_property_count,
                                   only_simple_this_property_assignments,
                                   this_property_assignments,
                                   num_parameters,
@@ skipping 186 matching lines @@
       beg_pos <= octal.beg_pos &&
       octal.end_pos <= end_pos) {
     ReportMessageAt(octal, "strict_octal_literal",
                     Vector<const char*>::empty());
     scanner().clear_octal_position();
     *ok = false;
   }
 }
 
 
+void Parser::CheckConflictingVarDeclarations(Scope* scope, bool* ok) {
+  Declaration* decl = scope->CheckConflictingVarDeclarations();
+  if (decl != NULL) {
+    // In harmony mode we treat conflicting variable bindinds as early
+    // errors. See ES5 16 for a definition of early errors.
+    Handle<String> name = decl->proxy()->name();
+    SmartPointer<char> c_string = name->ToCString(DISALLOW_NULLS);
+    const char* elms[2] = { "Variable", *c_string };
+    Vector<const char*> args(elms, 2);
+    int position = decl->proxy()->position();
+    Scanner::Location location = position == RelocInfo::kNoPosition
+        ? Scanner::Location::invalid()
+        : Scanner::Location(position, position + 1);
+    ReportMessageAt(location, "redeclaration", args);
+    *ok = false;
+  }
+}
+
+
 // This function reads an identifier name and determines whether or not it
 // is 'get' or 'set'.
 Handle<String> Parser::ParseIdentifierNameOrGetOrSet(bool* is_get,
                                                      bool* is_set,
                                                      bool* ok) {
   Handle<String> result = ParseIdentifierName(ok);
   if (!*ok) return Handle<String>();
   if (scanner().is_literal_ascii() && scanner().literal_length() == 3) {
     const char* token = scanner().literal_ascii_string().start();
     *is_get = strncmp(token, "get", 3) == 0;
@@ skipping 1101 matching lines @@
       result = parser.ParseProgram(source,
                                    info->is_global(),
                                    info->StrictMode());
     }
   }
   info->SetFunction(result);
   return (result != NULL);
 }
 
 } }  // namespace v8::internal