Strip Interface class of most of its logic, make it all about Module exports

src/parser.cc

 // Copyright 2012 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 "src/v8.h"
 
 #include "src/api.h"
 #include "src/ast.h"
 #include "src/bailout-reason.h"
 #include "src/base/platform/platform.h"
@@ skipping 693 matching lines @@
       DCHECK(false);
   }
   return NULL;
 }
 
 
 Expression* ParserTraits::ExpressionFromIdentifier(const AstRawString* name,
                                                    int pos, Scope* scope,
                                                    AstNodeFactory* factory) {
   if (parser_->fni_ != NULL) parser_->fni_->PushVariableName(name);
-  // The name may refer to a module instance object, so its type is unknown.
-#ifdef DEBUG
-  if (FLAG_print_interface_details)
-    PrintF("# Variable %.*s ", name->length(), name->raw_data());
-#endif
-  Interface* interface = Interface::NewUnknown(parser_->zone());
 
   // Arrow function parameters are parsed as an expression. When
   // parsing lazily, it is enough to create a VariableProxy in order
   // for Traits::DeclareArrowParametersFromExpression() to be able to
   // pick the names of the parameters.
   return parser_->parsing_lazy_arrow_parameters_
-      ? factory->NewVariableProxy(name, false, interface, pos)
-      : scope->NewUnresolved(factory, name, interface, pos);
+             ? factory->NewVariableProxy(name, false, pos)
+             : scope->NewUnresolved(factory, name, pos);
 }
 
 
 Expression* ParserTraits::ExpressionFromString(int pos, Scanner* scanner,
                                                AstNodeFactory* factory) {
   const AstRawString* symbol = GetSymbol(scanner);
   if (parser_->fni_ != NULL) parser_->fni_->PushLiteralName(symbol);
   return factory->NewStringLiteral(symbol, pos);
 }
 
@@ skipping 550 matching lines @@
   Interface* interface = scope->interface();
   for (Interface::Iterator it = interface->iterator();
        !it.done(); it.Advance()) {
     if (scope->LookupLocal(it.name()) == NULL) {
       ParserTraits::ReportMessage("module_export_undefined", it.name());
       *ok = false;
       return NULL;
     }
   }
 
-  interface->MakeModule(ok);
-  DCHECK(*ok);
-  interface->Freeze(ok);
-  DCHECK(*ok);
   return body;
 }
 
 
 Literal* Parser::ParseModuleSpecifier(bool* ok) {
   // ModuleSpecifier :
   //    StringLiteral
 
   int pos = peek_position();
   Expect(Token::STRING, CHECK_OK);
@@ skipping 303 matching lines @@
   // TODO(ES6): Handle 'export from' once imports are properly implemented.
   // For now we just drop such exports on the floor.
   if (!is_export_from) {
     // Extract declared names into export declarations and interface.
     Interface* interface = scope_->interface();
     for (int i = 0; i < names.length(); ++i) {
 #ifdef DEBUG
       if (FLAG_print_interface_details)
         PrintF("# Export %.*s ", names[i]->length(), names[i]->raw_data());
 #endif
-      Interface* inner = Interface::NewUnknown(zone());
-      interface->Add(names[i], inner, zone(), CHECK_OK);
-      if (!*ok) return NULL;
-      VariableProxy* proxy = NewUnresolved(names[i], LET, inner);
-      USE(proxy);
+      // TODO(adamk): Make early errors here provide the right error message
+      // (duplicate exported names).
+      interface->Add(names[i], zone(), CHECK_OK);
       // TODO(rossberg): Rethink whether we actually need to store export
       // declarations (for compilation?).
       // ExportDeclaration* declaration =
       //     factory()->NewExportDeclaration(proxy, scope_, position);
       // scope_->AddDeclaration(declaration);
     }
   }
 
   DCHECK(result != NULL);
   return result;
@@ skipping 112 matching lines @@
       }
 
     // Fall through.
     default:
       return ParseExpressionOrLabelledStatement(labels, ok);
   }
 }
 
 
 VariableProxy* Parser::NewUnresolved(const AstRawString* name,
-                                     VariableMode mode, Interface* interface) {
+                                     VariableMode mode) {
   // If we are inside a function, a declaration of a var/const variable is a
   // truly local variable, and the scope of the variable is always the function
   // scope.
   // Let/const variables in harmony mode are always added to the immediately
   // enclosing scope.
-  return DeclarationScope(mode)->NewUnresolved(
-      factory(), name, interface, position());
+  return DeclarationScope(mode)->NewUnresolved(factory(), name, position());
 }
 
 
 void Parser::Declare(Declaration* declaration, bool resolve, bool* ok) {
   VariableProxy* proxy = declaration->proxy();
   DCHECK(proxy->raw_name() != NULL);
   const AstRawString* name = proxy->raw_name();
   VariableMode mode = declaration->mode();
   Scope* declaration_scope = DeclarationScope(mode);
   Variable* var = NULL;
 
   // If a suitable scope exists, then we can statically declare this
   // variable and also set its mode. In any case, a Declaration node
   // will be added to the scope so that the declaration can be added
   // to the corresponding activation frame at runtime if necessary.
   // For instance declarations inside an eval scope need to be added
   // to the calling function context.
   // Similarly, strict mode eval scope does not leak variable declarations to
   // the caller's scope so we declare all locals, too.
   if (declaration_scope->is_function_scope() ||
       declaration_scope->is_strict_eval_scope() ||
       declaration_scope->is_block_scope() ||
       declaration_scope->is_module_scope() ||
       declaration_scope->is_script_scope()) {
     // Declare the variable in the declaration scope.
     var = declaration_scope->LookupLocal(name);
     if (var == NULL) {
       // Declare the name.
-      var = declaration_scope->DeclareLocal(name, mode,
-                                            declaration->initialization(),
-                                            kNotAssigned, proxy->interface());
+      var = declaration_scope->DeclareLocal(
+          name, mode, declaration->initialization(), kNotAssigned);
     } else if (IsLexicalVariableMode(mode) || IsLexicalVariableMode(var->mode())
                || ((mode == CONST_LEGACY || var->mode() == CONST_LEGACY) &&
                    !declaration_scope->is_script_scope())) {
       // 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 (in script scope, we also have to ignore legacy const for
       // compatibility). There is similar code in runtime.cc in the Declare
       // functions. The function CheckConflictingVarDeclarations checks for
       // var and let bindings from different scopes whereas this is a check for
       // conflicting declarations within the same scope. This check also covers
@@ skipping 34 matching lines @@
   // 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
   // RuntimeHidden_DeclareLookupSlot calls.
   declaration_scope->AddDeclaration(declaration);
 
   if (mode == CONST_LEGACY && declaration_scope->is_script_scope()) {
     // For global const variables we bind the proxy to a variable.
     DCHECK(resolve);  // should be set by all callers
     Variable::Kind kind = Variable::NORMAL;
-    var = new (zone())
-        Variable(declaration_scope, name, mode, true, kind,
-                 kNeedsInitialization, kNotAssigned, proxy->interface());
+    var = new (zone()) Variable(declaration_scope, name, mode, true, kind,
+                                kNeedsInitialization, kNotAssigned);
   } else if (declaration_scope->is_eval_scope() &&
              is_sloppy(declaration_scope->language_mode())) {
     // For variable declarations in a sloppy eval scope the proxy is bound
     // to a lookup variable to force a dynamic declaration using the
     // DeclareLookupSlot runtime function.
     Variable::Kind kind = Variable::NORMAL;
     // TODO(sigurds) figure out if kNotAssigned is OK here
     var = new (zone()) Variable(declaration_scope, name, mode, true, kind,
-                                declaration->initialization(), kNotAssigned,
-                                proxy->interface());
+                                declaration->initialization(), kNotAssigned);
     var->AllocateTo(Variable::LOOKUP, -1);
     resolve = true;
   }
 
   // If requested and we have a local variable, bind the proxy to the variable
   // at parse-time. This is used for functions (and consts) declared inside
   // statements: the corresponding function (or const) variable must be in the
   // function scope and not a statement-local scope, e.g. as provided with a
   // 'with' statement:
   //
@@ skipping 10 matching lines @@
   //
   // Note that if 'f' is accessed from inside the 'with' statement, it
   // will be allocated in the context (because we must be able to look
   // it up dynamically) but it will also be accessed statically, i.e.,
   // with a context slot index and a context chain length for this
   // initialization code. Thus, inside the 'with' statement, we need
   // both access to the static and the dynamic context chain; the
   // runtime needs to provide both.
   if (resolve && var != NULL) {
     proxy->BindTo(var);
-
-    if (FLAG_harmony_modules) {
-      bool ok;
-#ifdef DEBUG
-      if (FLAG_print_interface_details) {
-        PrintF("# Declare %.*s ", var->raw_name()->length(),
-               var->raw_name()->raw_data());
-      }
-#endif
-      proxy->interface()->Unify(var->interface(), zone(), &ok);
-      if (!ok) {
-#ifdef DEBUG
-        if (FLAG_print_interfaces) {
-          PrintF("DECLARE TYPE ERROR\n");
-          PrintF("proxy: ");
-          proxy->interface()->Print();
-          PrintF("var: ");
-          var->interface()->Print();
-        }
-#endif
-        ParserTraits::ReportMessage("module_type_error", name);
-      }
-    }
   }
 }
 
 
 // Language extension which is only enabled for source files loaded
 // through the API's extension mechanism.  A native function
 // declaration is resolved by looking up the function through a
 // callback provided by the extension.
 Statement* Parser::ParseNativeDeclaration(bool* ok) {
   int pos = peek_position();
@@ skipping 14 matching lines @@
 
   // Make sure that the function containing the native declaration
   // isn't lazily compiled. The extension structures are only
   // accessible while parsing the first time not when reparsing
   // because of lazy compilation.
   DeclarationScope(VAR)->ForceEagerCompilation();
 
   // TODO(1240846): It's weird that native function declarations are
   // introduced dynamically when we meet their declarations, whereas
   // other functions are set up when entering the surrounding scope.
-  VariableProxy* proxy = NewUnresolved(name, VAR, Interface::NewValue());
+  VariableProxy* proxy = NewUnresolved(name, VAR);
   Declaration* declaration =
       factory()->NewVariableDeclaration(proxy, VAR, scope_, pos);
   Declare(declaration, true, CHECK_OK);
   NativeFunctionLiteral* lit = factory()->NewNativeFunctionLiteral(
       name, extension_, RelocInfo::kNoPosition);
   return factory()->NewExpressionStatement(
       factory()->NewAssignment(
           Token::INIT_VAR, proxy, lit, RelocInfo::kNoPosition),
       pos);
 }
@@ skipping 22 matching lines @@
   // scope, we treat it as such and introduce the function with its
   // initial value upon entering the corresponding scope.
   // In ES6, a function behaves as a lexical binding, except in
   // a script scope, or the initial scope of eval or another function.
   VariableMode mode =
       allow_harmony_scoping() && is_strict(language_mode()) &&
               !(scope_->is_script_scope() || scope_->is_eval_scope() ||
                 scope_->is_function_scope())
           ? LET
           : VAR;
-  VariableProxy* proxy = NewUnresolved(name, mode, Interface::NewValue());
+  VariableProxy* proxy = NewUnresolved(name, mode);
   Declaration* declaration =
       factory()->NewFunctionDeclaration(proxy, mode, fun, scope_, pos);
   Declare(declaration, true, CHECK_OK);
   if (names) names->Add(name, zone());
   return factory()->NewEmptyStatement(RelocInfo::kNoPosition);
 }
 
 
 Statement* Parser::ParseClassDeclaration(ZoneList<const AstRawString*>* names,
                                          bool* ok) {
@@ skipping 17 matching lines @@
     return NULL;
   }
 
   int pos = position();
   bool is_strict_reserved = false;
   const AstRawString* name =
       ParseIdentifierOrStrictReservedWord(&is_strict_reserved, CHECK_OK);
   ClassLiteral* value = ParseClassLiteral(name, scanner()->location(),
                                           is_strict_reserved, pos, CHECK_OK);
 
-  VariableProxy* proxy = NewUnresolved(name, LET, Interface::NewValue());
+  VariableProxy* proxy = NewUnresolved(name, LET);
   Declaration* declaration =
       factory()->NewVariableDeclaration(proxy, LET, scope_, pos);
   Declare(declaration, true, CHECK_OK);
   proxy->var()->set_initializer_position(pos);
 
   Token::Value init_op = Token::INIT_LET;
   Assignment* assignment = factory()->NewAssignment(init_op, proxy, value, pos);
   Statement* assignment_statement =
       factory()->NewExpressionStatement(assignment, RelocInfo::kNoPosition);
   if (names) names->Add(name, zone());
@@ skipping 182 matching lines @@
     // For let/const declarations in harmony mode, we can also immediately
     // pre-resolve the proxy because it resides in the same scope as the
     // declaration.
     is_for_iteration_variable =
         var_context == kForStatement &&
         (peek() == Token::IN || PeekContextualKeyword(CStrVector("of")));
     if (is_for_iteration_variable && mode == CONST) {
       needs_init = false;
     }
 
-    Interface* interface =
-        is_const ? Interface::NewConst() : Interface::NewValue();
-    VariableProxy* proxy = NewUnresolved(name, mode, interface);
+    VariableProxy* proxy = NewUnresolved(name, mode);
     Declaration* declaration =
         factory()->NewVariableDeclaration(proxy, mode, scope_, pos);
     Declare(declaration, mode != VAR, CHECK_OK);
     nvars++;
     if (declaration_scope->num_var_or_const() > kMaxNumFunctionLocals) {
       ReportMessage("too_many_variables");
       *ok = false;
       return NULL;
     }
     if (names) names->Add(name, zone());
@@ skipping 143 matching lines @@
     }
 
     // Add an assignment node to the initialization statement block if we still
     // have a pending initialization value.
     if (value != NULL) {
       DCHECK(mode == VAR);
       // 'var' initializations are simply assignments (with all the consequences
       // if they are inside a 'with' statement - they may change a 'with' object
       // property).
       VariableProxy* proxy =
-          initialization_scope->NewUnresolved(factory(), name, interface);
+          initialization_scope->NewUnresolved(factory(), name);
       Assignment* assignment =
           factory()->NewAssignment(init_op, proxy, value, pos);
       block->AddStatement(
           factory()->NewExpressionStatement(assignment, RelocInfo::kNoPosition),
           zone());
     }
 
     if (fni_ != NULL) fni_->Leave();
   } while (peek() == Token::COMMA);
 
@@ skipping 615 matching lines @@
                                            RelocInfo::kNoPosition);
 
   // Add statement: let x = i.
   outer_block->AddStatement(init, zone());
 
   const AstRawString* temp_name = ast_value_factory()->dot_for_string();
 
   // For each let variable x:
   //   make statement: temp_x = x.
   for (int i = 0; i < names->length(); i++) {
-    VariableProxy* proxy =
-        NewUnresolved(names->at(i), LET, Interface::NewValue());
+    VariableProxy* proxy = NewUnresolved(names->at(i), LET);
     Variable* temp = scope_->DeclarationScope()->NewTemporary(temp_name);
     VariableProxy* temp_proxy = factory()->NewVariableProxy(temp);
     Assignment* assignment = factory()->NewAssignment(
         Token::ASSIGN, temp_proxy, proxy, RelocInfo::kNoPosition);
     Statement* assignment_statement = factory()->NewExpressionStatement(
         assignment, RelocInfo::kNoPosition);
     outer_block->AddStatement(assignment_statement, zone());
     temps.Add(temp, zone());
   }
 
@@ skipping 23 matching lines @@
   scope_ = inner_scope;
 
   Block* inner_block = factory()->NewBlock(NULL, names->length() + 4, false,
                                            RelocInfo::kNoPosition);
   int pos = scanner()->location().beg_pos;
   ZoneList<Variable*> inner_vars(names->length(), zone());
 
   // For each let variable x:
   //    make statement: let x = temp_x.
   for (int i = 0; i < names->length(); i++) {
-    VariableProxy* proxy =
-        NewUnresolved(names->at(i), LET, Interface::NewValue());
+    VariableProxy* proxy = NewUnresolved(names->at(i), LET);
     Declaration* declaration =
         factory()->NewVariableDeclaration(proxy, LET, scope_, pos);
     Declare(declaration, true, CHECK_OK);
     inner_vars.Add(declaration->proxy()->var(), zone());
     VariableProxy* temp_proxy = factory()->NewVariableProxy(temps.at(i));
     Assignment* assignment = factory()->NewAssignment(
         Token::INIT_LET, proxy, temp_proxy, pos);
     Statement* assignment_statement = factory()->NewExpressionStatement(
         assignment, pos);
     proxy->var()->set_initializer_position(pos);
@@ skipping 130 matching lines @@
   Scope* for_scope = NewScope(scope_, BLOCK_SCOPE);
   scope_ = for_scope;
 
   Expect(Token::FOR, CHECK_OK);
   Expect(Token::LPAREN, CHECK_OK);
   for_scope->set_start_position(scanner()->location().beg_pos);
   bool is_let_identifier_expression = false;
   if (peek() != Token::SEMICOLON) {
     if (peek() == Token::VAR ||
         (peek() == Token::CONST && is_sloppy(language_mode()))) {
-      bool is_const = peek() == Token::CONST;
       const AstRawString* name = NULL;
       VariableDeclarationProperties decl_props = kHasNoInitializers;
       Block* variable_statement =
           ParseVariableDeclarations(kForStatement, &decl_props, NULL, &name,
                                     CHECK_OK);
       bool accept_OF = decl_props == kHasNoInitializers;
       ForEachStatement::VisitMode mode;
       int each_pos = position();
 
       if (name != NULL && CheckInOrOf(accept_OF, &mode)) {
-        Interface* interface =
-            is_const ? Interface::NewConst() : Interface::NewValue();
         ForEachStatement* loop =
             factory()->NewForEachStatement(mode, labels, stmt_pos);
         Target target(&this->target_stack_, loop);
 
         Expression* enumerable = ParseExpression(true, CHECK_OK);
         Expect(Token::RPAREN, CHECK_OK);
 
-        VariableProxy* each =
-            scope_->NewUnresolved(factory(), name, interface, each_pos);
+        VariableProxy* each = scope_->NewUnresolved(factory(), name, each_pos);
         Statement* body = ParseStatement(NULL, CHECK_OK);
         InitializeForEachStatement(loop, each, enumerable, body);
         Block* result =
             factory()->NewBlock(NULL, 2, false, RelocInfo::kNoPosition);
         result->AddStatement(variable_statement, zone());
         result->AddStatement(loop, zone());
         scope_ = saved_scope;
         for_scope->set_end_position(scanner()->location().end_pos);
         for_scope = for_scope->FinalizeBlockScope();
         DCHECK(for_scope == NULL);
@@ skipping 37 matching lines @@
         ForEachStatement* loop =
             factory()->NewForEachStatement(mode, labels, stmt_pos);
         Target target(&this->target_stack_, loop);
 
         // The expression does not see the loop variable.
         scope_ = saved_scope;
         Expression* enumerable = ParseExpression(true, CHECK_OK);
         scope_ = for_scope;
         Expect(Token::RPAREN, CHECK_OK);
 
-        VariableProxy* each = scope_->NewUnresolved(
-            factory(), name, Interface::NewValue(), each_pos);
+        VariableProxy* each = scope_->NewUnresolved(factory(), name, each_pos);
         Statement* body = ParseStatement(NULL, CHECK_OK);
         Block* body_block =
             factory()->NewBlock(NULL, 3, false, RelocInfo::kNoPosition);
         Token::Value init_op = is_const ? Token::INIT_CONST : Token::ASSIGN;
         Assignment* assignment = factory()->NewAssignment(
             init_op, each, temp_proxy, RelocInfo::kNoPosition);
         Statement* assignment_statement = factory()->NewExpressionStatement(
             assignment, RelocInfo::kNoPosition);
         body_block->AddStatement(variable_statement, zone());
         body_block->AddStatement(assignment_statement, zone());
@@ skipping 419 matching lines @@
     if (function_type == FunctionLiteral::NAMED_EXPRESSION) {
       if (allow_harmony_scoping() && is_strict(language_mode())) {
         fvar_init_op = Token::INIT_CONST;
       }
       VariableMode fvar_mode =
           allow_harmony_scoping() && is_strict(language_mode()) ? CONST
                                                                 : CONST_LEGACY;
       DCHECK(function_name != NULL);
       fvar = new (zone())
           Variable(scope_, function_name, fvar_mode, true /* is valid LHS */,
-                   Variable::NORMAL, kCreatedInitialized, kNotAssigned,
-                   Interface::NewConst());
+                   Variable::NORMAL, kCreatedInitialized, kNotAssigned);
       VariableProxy* proxy = factory()->NewVariableProxy(fvar);
       VariableDeclaration* fvar_declaration = factory()->NewVariableDeclaration(
           proxy, fvar_mode, scope_, RelocInfo::kNoPosition);
       scope_->DeclareFunctionVar(fvar_declaration);
     }
 
     // Determine if the function can be parsed lazily. Lazy parsing is different
     // from lazy compilation; we need to parse more eagerly than we compile.
 
     // We can only parse lazily if we also compile lazily. The heuristics for
@@ skipping 160 matching lines @@
 
 
 ZoneList<Statement*>* Parser::ParseEagerFunctionBody(
     const AstRawString* function_name, int pos, Variable* fvar,
     Token::Value fvar_init_op, FunctionKind kind, bool* ok) {
   // Everything inside an eagerly parsed function will be parsed eagerly
   // (see comment above).
   ParsingModeScope parsing_mode(this, PARSE_EAGERLY);
   ZoneList<Statement*>* body = new(zone()) ZoneList<Statement*>(8, zone());
   if (fvar != NULL) {
-    VariableProxy* fproxy = scope_->NewUnresolved(
-        factory(), function_name, Interface::NewConst());
+    VariableProxy* fproxy = scope_->NewUnresolved(factory(), function_name);
     fproxy->BindTo(fvar);
     body->Add(factory()->NewExpressionStatement(
         factory()->NewAssignment(fvar_init_op,
                                  fproxy,
                                  factory()->NewThisFunction(pos),
                                  RelocInfo::kNoPosition),
         RelocInfo::kNoPosition), zone());
   }
 
 
@@ skipping 109 matching lines @@
   }
 
   Scope* block_scope = NewScope(scope_, BLOCK_SCOPE);
   BlockState block_state(&scope_, block_scope);
   scope_->SetLanguageMode(
       static_cast<LanguageMode>(scope_->language_mode() | STRICT_BIT));
   scope_->SetScopeName(name);
 
   VariableProxy* proxy = NULL;
   if (name != NULL) {
-    proxy = NewUnresolved(name, CONST, Interface::NewConst());
+    proxy = NewUnresolved(name, CONST);
     Declaration* declaration =
         factory()->NewVariableDeclaration(proxy, CONST, block_scope, pos);
     Declare(declaration, true, CHECK_OK);
   }
 
   Expression* extends = NULL;
   if (Check(Token::EXTENDS)) {
     block_scope->set_start_position(scanner()->location().end_pos);
     extends = ParseLeftHandSideExpression(CHECK_OK);
   } else {
@@ skipping 1376 matching lines @@
     } else {
       const uc16* data = reinterpret_cast<const uc16*>(raw_string->raw_data());
       running_hash = StringHasher::ComputeRunningHash(running_hash, data,
                                                       raw_string->length());
     }
   }
 
   return running_hash;
 }
 } }  // namespace v8::internal