Basic interface inference for modules.

src/scopes.cc

Index: src/scopes.cc
diff --git a/src/scopes.cc b/src/scopes.cc
index 8d71f8ae858d8b44937bea0e25dc69b379a60f7f..766e1ae5cccc7c5e42512cdaccdf2f634b1ca0aa 100644
--- a/src/scopes.cc
+++ b/src/scopes.cc
@@ -67,7 +67,8 @@ Variable* VariableMap::Declare(
     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.
@@ -77,7 +78,8 @@ Variable* VariableMap::Declare(
                             mode,
                             is_valid_lhs,
                             kind,
-                            initialization_flag);
+                            initialization_flag,
+                            interface);
   }
   return reinterpret_cast<Variable*>(p->value);
 }
@@ -105,6 +107,9 @@ Scope::Scope(Scope* outer_scope, ScopeType type)
       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
@@ -125,6 +130,7 @@ Scope::Scope(Scope* inner_scope,
       params_(4),
       unresolved_(16),
       decls_(4),
+      interface_(NULL),
       already_resolved_(true) {
   SetDefaults(type, NULL, scope_info);
   if (!scope_info.is_null()) {
@@ -145,6 +151,7 @@ Scope::Scope(Scope* inner_scope, Handle<String> catch_variable_name)
       params_(0),
       unresolved_(0),
       decls_(0),
+      interface_(NULL),
       already_resolved_(true) {
   SetDefaults(CATCH_SCOPE, NULL, Handle<ScopeInfo>::null());
   AddInnerScope(inner_scope);
@@ -255,7 +262,7 @@ bool Scope::Analyze(CompilationInfo* info) {
   // 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
@@ -264,6 +271,11 @@ bool Scope::Analyze(CompilationInfo* info) {
           : 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) {
@@ -438,7 +450,8 @@ void Scope::DeclareParameter(Handle<String> name, VariableMode mode) {
 
 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
@@ -448,8 +461,8 @@ Variable* Scope::DeclareLocal(Handle<String> name,
          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);
 }
 
 
@@ -586,7 +599,7 @@ void Scope::CollectStackAndContextLocals(ZoneList<Variable*>* stack_locals,
 }
 
 
-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;
@@ -598,10 +611,12 @@ void Scope::AllocateVariables(Scope* global_scope,
   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;
 }
 
 
@@ -916,14 +931,14 @@ Variable* Scope::LookupRecursive(Handle<String> name,
 }
 
 
-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;
@@ -947,8 +962,7 @@ void Scope::ResolveVariable(Scope* global_scope,
 
     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:
@@ -965,23 +979,62 @@ void Scope::ResolveVariable(Scope* global_scope,
 
   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))
+      return false;
   }
+
+  return true;
 }