[bootstrapper] add checks for variable bindings in native scripts.

Native scripts must not accidentally pollute the global object.

R=bmeurer@chromium.org

Review URL: https://codereview.chromium.org/1490783002

Cr-Commit-Position: refs/heads/master@{#32469}

src/ast/scopes.cc

@@ -308,14 +308,10 @@ bool Scope::Analyze(ParseInfo* info) {
   }
 
 #ifdef DEBUG
-  bool native = info->isolate()->bootstrapper()->IsActive();
-  if (!info->shared_info().is_null()) {
-    Object* script = info->shared_info()->script();
-    native = script->IsScript() &&
-             Script::cast(script)->type() == Script::TYPE_NATIVE;
+  if (info->script_is_native() ? FLAG_print_builtin_scopes
+                               : FLAG_print_scopes) {
+    scope->Print();
   }
-
-  if (native ? FLAG_print_builtin_scopes : FLAG_print_scopes) scope->Print();
 #endif
 
   info->set_scope(scope);
@@ -1161,6 +1157,22 @@ bool Scope::ResolveVariable(ParseInfo* info, VariableProxy* proxy,
   // Otherwise, try to resolve the variable.
   BindingKind binding_kind;
   Variable* var = LookupRecursive(proxy, &binding_kind, factory);
+
+#ifdef DEBUG
+  if (info->script_is_native()) {
+    // To avoid polluting the global object in native scripts
+    //  - Variables must not be allocated to the global scope.
+    CHECK_NOT_NULL(outer_scope());
+    //  - Variables must be bound locally or unallocated.
+    CHECK_EQ(BOUND, binding_kind);
+    VariableLocation location = var->location();
+    CHECK(location == VariableLocation::LOCAL ||
+          location == VariableLocation::CONTEXT ||
+          location == VariableLocation::PARAMETER ||
+          location == VariableLocation::UNALLOCATED);
+  }
+#endif
+
   switch (binding_kind) {
     case BOUND:
       // We found a variable binding.

src/bootstrapper.cc

@@ -3149,8 +3149,6 @@ Genesis::Genesis(Isolate* isolate,
     InitializeGlobal(global_object, empty_function, context_type);
     InitializeNormalizedMapCaches();
 
-    // TODO(yangguo): Find a way to prevent accidentially installing properties
-    // on the global object.
     if (!InstallNatives(context_type)) return;
 
     MakeFunctionInstancePrototypeWritable();

src/d8.cc

@@ -1086,7 +1086,7 @@ void Shell::InstallUtilityScript(Isolate* isolate) {
           i::JSFunction::cast(*compiled_script)->shared()->script()))
       : i::Handle<i::Script>(i::Script::cast(
           i::SharedFunctionInfo::cast(*compiled_script)->script()));
-  script_object->set_type(i::Script::TYPE_NATIVE);
+  script_object->set_type(i::Script::TYPE_EXTENSION);
 }
 #endif  // !V8_SHARED
 

src/js/date.js

@@ -70,12 +70,6 @@ function MakeTime(hour, min, sec, ms) {
 }
 
 
-// ECMA 262 - 15.9.1.12
-function TimeInYear(year) {
-  return DaysInYear(year) * msPerDay;
-}
-
-
 // Compute number of days given a year, month, date.
 // Note that month and date can lie outside the normal range.
 //   For example:

src/parsing/parser.h

@@ -151,6 +151,10 @@ class ParseInfo {
     context_ = Handle<Context>(*context_);
   }
 
+#ifdef DEBUG
+  bool script_is_native() { return script_->type() == Script::TYPE_NATIVE; }
+#endif  // DEBUG
+
  private:
   // Various configuration flags for parsing.
   enum Flag {