Strawman: check strong mode free variables against the global object.

src/scopeinfo.cc

 // Copyright 2011 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 <stdlib.h>
 
 #include "src/v8.h"
 
 #include "src/scopeinfo.h"
 #include "src/scopes.h"
 
 namespace v8 {
 namespace internal {
 
 
 Handle<ScopeInfo> ScopeInfo::Create(Isolate* isolate, Zone* zone,
                                     Scope* scope) {
   // Collect stack and context locals.
   ZoneList<Variable*> stack_locals(scope->StackLocalCount(), zone);
   ZoneList<Variable*> context_locals(scope->ContextLocalCount(), zone);
-  scope->CollectStackAndContextLocals(&stack_locals, &context_locals);
+  ZoneList<Variable*> strong_mode_free_variables(0, zone);
+
+  scope->CollectStackAndContextLocals(&stack_locals, &context_locals,
+                                      &strong_mode_free_variables);
   const int stack_local_count = stack_locals.length();
   const int context_local_count = context_locals.length();
+  const int strong_mode_free_variable_count =
+      strong_mode_free_variables.length();
   // Make sure we allocate the correct amount.
   DCHECK(scope->StackLocalCount() == stack_local_count);
   DCHECK(scope->ContextLocalCount() == context_local_count);
 
   bool simple_parameter_list =
       scope->is_function_scope() ? scope->is_simple_parameter_list() : true;
 
   // Determine use and location of the function variable if it is present.
   FunctionVariableInfo function_name_info;
   VariableMode function_variable_mode;
   if (scope->is_function_scope() && scope->function() != NULL) {
     Variable* var = scope->function()->proxy()->var();
     if (!var->is_used()) {
       function_name_info = UNUSED;
     } else if (var->IsContextSlot()) {
       function_name_info = CONTEXT;
     } else {
       DCHECK(var->IsStackLocal());
       function_name_info = STACK;
     }
     function_variable_mode = var->mode();
   } else {
     function_name_info = NONE;
     function_variable_mode = VAR;
   }
 
   const bool has_function_name = function_name_info != NONE;
   const int parameter_count = scope->num_parameters();
-  const int length = kVariablePartIndex
-      + parameter_count + stack_local_count + 2 * context_local_count
-      + (has_function_name ? 2 : 0);
+  const int length = kVariablePartIndex + parameter_count + stack_local_count +
+                     2 * context_local_count + (has_function_name ? 2 : 0) +
+                     strong_mode_free_variable_count;
 
   Factory* factory = isolate->factory();
   Handle<ScopeInfo> scope_info = factory->NewScopeInfo(length);
 
   // Encode the flags.
   int flags = ScopeTypeField::encode(scope->scope_type()) |
               CallsEvalField::encode(scope->calls_eval()) |
               LanguageModeField::encode(scope->language_mode()) |
               FunctionVariableField::encode(function_name_info) |
               FunctionVariableMode::encode(function_variable_mode) |
               AsmModuleField::encode(scope->asm_module()) |
               AsmFunctionField::encode(scope->asm_function()) |
               IsSimpleParameterListField::encode(simple_parameter_list) |
               BlockScopeIsClassScopeField::encode(scope->is_class_scope()) |
               FunctionKindField::encode(scope->function_kind());
   scope_info->SetFlags(flags);
   scope_info->SetParameterCount(parameter_count);
   scope_info->SetStackLocalCount(stack_local_count);
   scope_info->SetContextLocalCount(context_local_count);
+  scope_info->SetStrongModeFreeVariableCount(strong_mode_free_variable_count);
 
   int index = kVariablePartIndex;
   // Add parameters.
   DCHECK(index == scope_info->ParameterEntriesIndex());
   for (int i = 0; i < parameter_count; ++i) {
     scope_info->set(index++, *scope->parameter(i)->name());
   }
 
   // Add stack locals' names. We are assuming that the stack locals'
   // slots are allocated in increasing order, so we can simply add
@@ skipping 22 matching lines @@
   DCHECK(index == scope_info->ContextLocalInfoEntriesIndex());
   for (int i = 0; i < context_local_count; ++i) {
     Variable* var = context_locals[i];
     uint32_t value =
         ContextLocalMode::encode(var->mode()) |
         ContextLocalInitFlag::encode(var->initialization_flag()) |
         ContextLocalMaybeAssignedFlag::encode(var->maybe_assigned());
     scope_info->set(index++, Smi::FromInt(value));
   }
 
+  DCHECK(index == scope_info->StrongModeFreeVariableEntriesIndex());
+  for (int i = 0; i < strong_mode_free_variable_count; ++i) {
+    scope_info->set(index++, *strong_mode_free_variables[i]->name());
+  }
+
   // If present, add the function variable name and its index.
   DCHECK(index == scope_info->FunctionNameEntryIndex());
   if (has_function_name) {
     int var_index = scope->function()->proxy()->var()->index();
     scope_info->set(index++, *scope->function()->proxy()->name());
     scope_info->set(index++, Smi::FromInt(var_index));
     DCHECK(function_name_info != STACK ||
            (var_index == scope_info->StackLocalCount() &&
             var_index == scope_info->StackSlotCount() - 1));
     DCHECK(function_name_info != CONTEXT ||
@@ skipping 152 matching lines @@
   DCHECK(0 <= var && var < LocalCount());
   // There's currently no flag stored on the ScopeInfo to indicate that a
   // variable is a compiler-introduced temporary. However, to avoid conflict
   // with user declarations, the current temporaries like .generator_object and
   // .result start with a dot, so we can use that as a flag. It's a hack!
   Handle<String> name(LocalName(var));
   return name->length() > 0 && name->Get(0) == '.';
 }
 
 
+String* ScopeInfo::StrongModeFreeVariableName(int var) {
+  DCHECK(0 <= var && var < StrongModeFreeVariableCount());
+  int info_index = StrongModeFreeVariableEntriesIndex() + var;
+  return String::cast(get(info_index));
+}
+
+
 int ScopeInfo::StackSlotIndex(String* name) {
   DCHECK(name->IsInternalizedString());
   if (length() > 0) {
     int start = StackLocalEntriesIndex();
     int end = StackLocalEntriesIndex() + StackLocalCount();
     for (int i = start; i < end; ++i) {
       if (name == get(i)) {
         return i - start;
       }
     }
@@ skipping 127 matching lines @@
 int ScopeInfo::ContextLocalNameEntriesIndex() {
   return StackLocalEntriesIndex() + StackLocalCount();
 }
 
 
 int ScopeInfo::ContextLocalInfoEntriesIndex() {
   return ContextLocalNameEntriesIndex() + ContextLocalCount();
 }
 
 
+int ScopeInfo::StrongModeFreeVariableEntriesIndex() {
+  return ContextLocalInfoEntriesIndex() + ContextLocalCount();
+}
+
+
 int ScopeInfo::FunctionNameEntryIndex() {
-  return ContextLocalInfoEntriesIndex() + ContextLocalCount();
+  return StrongModeFreeVariableEntriesIndex() + StrongModeFreeVariableCount();
 }
 
 
 int ContextSlotCache::Hash(Object* data, String* name) {
   // Uses only lower 32 bits if pointers are larger.
   uintptr_t addr_hash =
       static_cast<uint32_t>(reinterpret_cast<uintptr_t>(data)) >> 2;
   return static_cast<int>((addr_hash ^ name->Hash()) % kLength);
 }
 
@@ skipping 129 matching lines @@
     info->set_name(i, *(it.export_name()->string()));
     info->set_mode(i, var->mode());
     DCHECK(var->index() >= 0);
     info->set_index(i, var->index());
   }
   DCHECK(i == info->length());
   return info;
 }
 
 } }  // namespace v8::internal