Basic interface inference for modules.

src/scopes.cc

 // Copyright 2012 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 49 matching lines @@
 VariableMap::VariableMap() : ZoneHashMap(Match, 8) {}
 VariableMap::~VariableMap() {}
 
 
 Variable* VariableMap::Declare(
     Scope* scope,
     Handle<String> name,
     VariableMode mode,
     bool is_valid_lhs,
     Variable::Kind kind,
-    InitializationFlag initialization_flag) {
+    InitializationFlag initialization_flag,
+    Interface* interface) {
   Entry* p = ZoneHashMap::Lookup(name.location(), name->Hash(), true);
   if (p->value == NULL) {
     // The variable has not been declared yet -> insert it.
     ASSERT(p->key == name.location());
     p->value = new Variable(scope,
                             name,
                             mode,
                             is_valid_lhs,
                             kind,
-                            initialization_flag);
+                            initialization_flag,
+                            interface);
   }
   return reinterpret_cast<Variable*>(p->value);
 }
 
 
 Variable* VariableMap::Lookup(Handle<String> name) {
   Entry* p = ZoneHashMap::Lookup(name.location(), name->Hash(), false);
   if (p != NULL) {
     ASSERT(*reinterpret_cast<String**>(p->key) == *name);
     ASSERT(p->value != NULL);
     return reinterpret_cast<Variable*>(p->value);
   }
   return NULL;
 }
 
 
 // ----------------------------------------------------------------------------
 // Implementation of Scope
 
 Scope::Scope(Scope* outer_scope, ScopeType type)
     : isolate_(Isolate::Current()),
       inner_scopes_(4),
       variables_(),
       temps_(4),
       params_(4),
       unresolved_(16),
       decls_(4),
+      interface_(FLAG_harmony_modules &&
+                 (type == MODULE_SCOPE || type == GLOBAL_SCOPE)
+                     ? Interface::NewModule() : NULL),
       already_resolved_(false) {
   SetDefaults(type, outer_scope, Handle<ScopeInfo>::null());
   // At some point we might want to provide outer scopes to
   // eval scopes (by walking the stack and reading the scope info).
   // In that case, the ASSERT below needs to be adjusted.
   ASSERT_EQ(type == GLOBAL_SCOPE, outer_scope == NULL);
   ASSERT(!HasIllegalRedeclaration());
 }
 
 
 Scope::Scope(Scope* inner_scope,
              ScopeType type,
              Handle<ScopeInfo> scope_info)
     : isolate_(Isolate::Current()),
       inner_scopes_(4),
       variables_(),
       temps_(4),
       params_(4),
       unresolved_(16),
       decls_(4),
+      interface_(NULL),
       already_resolved_(true) {
   SetDefaults(type, NULL, scope_info);
   if (!scope_info.is_null()) {
     num_heap_slots_ = scope_info_->ContextLength();
   }
   // Ensure at least MIN_CONTEXT_SLOTS to indicate a materialized context.
   num_heap_slots_ = Max(num_heap_slots_,
                         static_cast<int>(Context::MIN_CONTEXT_SLOTS));
   AddInnerScope(inner_scope);
 }
 
 
 Scope::Scope(Scope* inner_scope, Handle<String> catch_variable_name)
     : isolate_(Isolate::Current()),
       inner_scopes_(1),
       variables_(),
       temps_(0),
       params_(0),
       unresolved_(0),
       decls_(0),
+      interface_(NULL),
       already_resolved_(true) {
   SetDefaults(CATCH_SCOPE, NULL, Handle<ScopeInfo>::null());
   AddInnerScope(inner_scope);
   ++num_var_or_const_;
   num_heap_slots_ = Context::MIN_CONTEXT_SLOTS;
   Variable* variable = variables_.Declare(this,
                                           catch_variable_name,
                                           VAR,
                                           true,  // Valid left-hand side.
                                           Variable::NORMAL,
@@ skipping 90 matching lines @@
   // Traverse the scope tree up to the first unresolved scope or the global
   // scope and start scope resolution and variable allocation from that scope.
   while (!top->is_global_scope() &&
          !top->outer_scope()->already_resolved()) {
     top = top->outer_scope();
   }
 
   // Allocate the variables.
   {
     AstNodeFactory<AstNullVisitor> ast_node_factory(info->isolate());
-    top->AllocateVariables(info->global_scope(), &ast_node_factory);
+    if (!top->AllocateVariables(info, &ast_node_factory)) return false;
   }
 
 #ifdef DEBUG
   if (info->isolate()->bootstrapper()->IsActive()
           ? FLAG_print_builtin_scopes
           : FLAG_print_scopes) {
     scope->Print();
   }
+
+  if (FLAG_harmony_modules && FLAG_print_interfaces && top->is_global_scope()) {
+    PrintF("global : ");
+    top->interface()->Print();
+  }
 #endif
 
   if (FLAG_harmony_scoping) {
     VariableProxy* proxy = scope->CheckAssignmentToConst();
     if (proxy != NULL) {
       // Found an assignment to const. Throw a syntax error.
       MessageLocation location(info->script(),
                                proxy->position(),
                                proxy->position());
       Isolate* isolate = info->isolate();
@@ skipping 154 matching lines @@
   ASSERT(!already_resolved());
   ASSERT(is_function_scope());
   Variable* var = variables_.Declare(
       this, name, mode, true, Variable::NORMAL, kCreatedInitialized);
   params_.Add(var);
 }
 
 
 Variable* Scope::DeclareLocal(Handle<String> name,
                               VariableMode mode,
-                              InitializationFlag init_flag) {
+                              InitializationFlag init_flag,
+                              Interface* interface) {
   ASSERT(!already_resolved());
   // This function handles VAR and CONST modes.  DYNAMIC variables are
   // introduces during variable allocation, INTERNAL variables are allocated
   // explicitly, and TEMPORARY variables are allocated via NewTemporary().
   ASSERT(mode == VAR ||
          mode == CONST ||
          mode == CONST_HARMONY ||
          mode == LET);
   ++num_var_or_const_;
-  return
-      variables_.Declare(this, name, mode, true, Variable::NORMAL, init_flag);
+  return variables_.Declare(
+      this, name, mode, true, Variable::NORMAL, init_flag, interface);
 }
 
 
 Variable* Scope::DeclareGlobal(Handle<String> name) {
   ASSERT(is_global_scope());
   return variables_.Declare(this,
                             name,
                             DYNAMIC_GLOBAL,
                             true,
                             Variable::NORMAL,
@@ skipping 116 matching lines @@
       if (var->IsStackLocal()) {
         stack_locals->Add(var);
       } else if (var->IsContextSlot()) {
         context_locals->Add(var);
       }
     }
   }
 }
 
 
-void Scope::AllocateVariables(Scope* global_scope,
+bool Scope::AllocateVariables(CompilationInfo* info,
                               AstNodeFactory<AstNullVisitor>* factory) {
   // 1) Propagate scope information.
   bool outer_scope_calls_non_strict_eval = false;
   if (outer_scope_ != NULL) {
     outer_scope_calls_non_strict_eval =
         outer_scope_->outer_scope_calls_non_strict_eval() |
         outer_scope_->calls_non_strict_eval();
   }
   PropagateScopeInfo(outer_scope_calls_non_strict_eval);
 
   // 2) Resolve variables.
-  ResolveVariablesRecursively(global_scope, factory);
+  if (!ResolveVariablesRecursively(info, factory)) return false;
 
   // 3) Allocate variables.
   AllocateVariablesRecursively();
+
+  return true;
 }
 
 
 bool Scope::AllowsLazyCompilation() const {
   return !force_eager_compilation_ && HasTrivialOuterContext();
 }
 
 
 bool Scope::HasTrivialContext() const {
   // A function scope has a trivial context if it always is the global
@@ skipping 294 matching lines @@
     if (*binding_kind == BOUND) {
       *binding_kind = BOUND_EVAL_SHADOWED;
     } else if (*binding_kind == UNBOUND) {
       *binding_kind = UNBOUND_EVAL_SHADOWED;
     }
   }
   return var;
 }
 
 
-void Scope::ResolveVariable(Scope* global_scope,
+bool Scope::ResolveVariable(CompilationInfo* info,
                             VariableProxy* proxy,
                             AstNodeFactory<AstNullVisitor>* factory) {
-  ASSERT(global_scope == NULL || global_scope->is_global_scope());
+  ASSERT(info->global_scope()->is_global_scope());
 
   // If the proxy is already resolved there's nothing to do
   // (functions and consts may be resolved by the parser).
-  if (proxy->var() != NULL) return;
+  if (proxy->var() != NULL) return true;
 
   // Otherwise, try to resolve the variable.
   BindingKind binding_kind;
   Variable* var = LookupRecursive(proxy->name(), &binding_kind, factory);
   switch (binding_kind) {
     case BOUND:
       // We found a variable binding.
       break;
 
     case BOUND_EVAL_SHADOWED:
       // We found a variable variable binding that might be shadowed
       // by 'eval' introduced variable bindings.
       if (var->is_global()) {
         var = NonLocal(proxy->name(), DYNAMIC_GLOBAL);
       } else {
         Variable* invalidated = var;
         var = NonLocal(proxy->name(), DYNAMIC_LOCAL);
         var->set_local_if_not_shadowed(invalidated);
       }
       break;
 
     case UNBOUND:
       // No binding has been found. Declare a variable in global scope.
-      ASSERT(global_scope != NULL);
-      var = global_scope->DeclareGlobal(proxy->name());
+      var = info->global_scope()->DeclareGlobal(proxy->name());
       break;
 
     case UNBOUND_EVAL_SHADOWED:
       // No binding has been found. But some scope makes a
       // non-strict 'eval' call.
       var = NonLocal(proxy->name(), DYNAMIC_GLOBAL);
       break;
 
     case DYNAMIC_LOOKUP:
       // The variable could not be resolved statically.
       var = NonLocal(proxy->name(), DYNAMIC);
       break;
   }
 
   ASSERT(var != NULL);
   proxy->BindTo(var);
+
+  if (FLAG_harmony_modules) {
+    bool ok;
+#ifdef DEBUG
+    if (FLAG_print_interface_details)
+      PrintF("# Resolve %s:\n", var->name()->ToAsciiArray());
+#endif
+    proxy->interface()->Unify(var->interface(), &ok);
+    if (!ok) {
+#ifdef DEBUG
+      if (FLAG_print_interfaces) {
+        PrintF("SCOPES TYPE ERROR\n");
+        PrintF("proxy: ");
+        proxy->interface()->Print();
+        PrintF("var: ");
+        var->interface()->Print();
+      }
+#endif
+
+      // Inconsistent use of module. Throw a syntax error.
+      // TODO(rossberg): generate more helpful error message.
+      MessageLocation location(info->script(),
+                               proxy->position(),
+                               proxy->position());
+      Isolate* isolate = Isolate::Current();
+      Factory* factory = isolate->factory();
+      Handle<JSArray> array = factory->NewJSArray(1);
+      array->SetElement(array, 0, var->name(), NONE, kStrictMode);
+      Handle<Object> result =
+          factory->NewSyntaxError("module_type_error", array);
+      isolate->Throw(*result, &location);
+      return false;
+    }
+  }
+
+  return true;
 }
 
 
-void Scope::ResolveVariablesRecursively(
-    Scope* global_scope,
+bool Scope::ResolveVariablesRecursively(
+    CompilationInfo* info,
     AstNodeFactory<AstNullVisitor>* factory) {
-  ASSERT(global_scope == NULL || global_scope->is_global_scope());
+  ASSERT(info->global_scope()->is_global_scope());
 
   // Resolve unresolved variables for this scope.
   for (int i = 0; i < unresolved_.length(); i++) {
-    ResolveVariable(global_scope, unresolved_[i], factory);
+    if (!ResolveVariable(info, unresolved_[i], factory)) return false;
   }
 
   // Resolve unresolved variables for inner scopes.
   for (int i = 0; i < inner_scopes_.length(); i++) {
-    inner_scopes_[i]->ResolveVariablesRecursively(global_scope, factory);
+    if (!inner_scopes_[i]->ResolveVariablesRecursively(info, factory))

[Sven Panne, 2012/03/08 08:55:00]

I know that this recursive call has been there before, but shouldn't we guard
against pathological cases/attacks here?

[rossberg, 2012/03/08 10:47:06]

See my respective comment in interface.cc.

+      return false;
   }
+
+  return true;
 }
 
 
 bool Scope::PropagateScopeInfo(bool outer_scope_calls_non_strict_eval ) {
   if (outer_scope_calls_non_strict_eval) {
     outer_scope_calls_non_strict_eval_ = true;
   }
 
   bool calls_non_strict_eval =
       this->calls_non_strict_eval() || outer_scope_calls_non_strict_eval_;
@@ skipping 202 matching lines @@
 }
 
 
 int Scope::ContextLocalCount() const {
   if (num_heap_slots() == 0) return 0;
   return num_heap_slots() - Context::MIN_CONTEXT_SLOTS -
       (function_ != NULL && function_->var()->IsContextSlot() ? 1 : 0);
 }
 
 } }  // namespace v8::internal