Reapply "Resolve references to "this" the same way as normal variables""

src/scopes.h

 // 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.
 
 #ifndef V8_SCOPES_H_
 #define V8_SCOPES_H_
 
 #include "src/ast.h"
 #include "src/pending-compilation-error-handler.h"
 #include "src/zone.h"
@@ skipping 126 matching lines @@
 
   // Declare an implicit global variable in this scope which must be a
   // script scope.  The variable was introduced (possibly from an inner
   // scope) by a reference to an unresolved variable with no intervening
   // with statements or eval calls.
   Variable* DeclareDynamicGlobal(const AstRawString* name);
 
   // Create a new unresolved variable.
   VariableProxy* NewUnresolved(AstNodeFactory* factory,
                                const AstRawString* name,
+                               Variable::Kind kind = Variable::NORMAL,
                                int start_position = RelocInfo::kNoPosition,
                                int end_position = RelocInfo::kNoPosition) {
     // Note that we must not share the unresolved variables with
     // the same name because they may be removed selectively via
     // RemoveUnresolved().
     DCHECK(!already_resolved());
-    VariableProxy* proxy = factory->NewVariableProxy(
-        name, Variable::NORMAL, start_position, end_position);
+    VariableProxy* proxy =
+        factory->NewVariableProxy(name, kind, start_position, end_position);
     unresolved_.Add(proxy, zone_);
     return proxy;
   }
 
   // Remove a unresolved variable. During parsing, an unresolved variable
   // may have been added optimistically, but then only the variable name
   // was used (typically for labels). If the variable was not declared, the
   // addition introduced a new unresolved variable which may end up being
   // allocated globally as a "ghost" variable. RemoveUnresolved removes
   // such a variable again if it was added; otherwise this is a no-op.
@@ skipping 45 matching lines @@
 
   // Inform the scope that the corresponding code contains an eval call.
   void RecordEvalCall() { if (!is_script_scope()) scope_calls_eval_ = true; }
 
   // Inform the scope that the corresponding code uses "arguments".
   void RecordArgumentsUsage() { scope_uses_arguments_ = true; }
 
   // Inform the scope that the corresponding code uses "super".
   void RecordSuperPropertyUsage() { scope_uses_super_property_ = true; }
 
-  // Inform the scope that the corresponding code uses "this".
-  void RecordThisUsage() { scope_uses_this_ = true; }
-
   // Set the language mode flag (unless disabled by a global flag).
   void SetLanguageMode(LanguageMode language_mode) {
     language_mode_ = language_mode;
   }
 
   // Set the ASM module flag.
   void SetAsmModule() { asm_module_ = true; }
 
   // Position in the source where this scope begins and ends.
   //
@@ skipping 83 matching lines @@
   // Does this scope access "arguments".
   bool uses_arguments() const { return scope_uses_arguments_; }
   // Does any inner scope access "arguments".
   bool inner_uses_arguments() const { return inner_scope_uses_arguments_; }
   // Does this scope access "super" property (super.foo).
   bool uses_super_property() const { return scope_uses_super_property_; }
   // Does any inner scope access "super" property.
   bool inner_uses_super_property() const {
     return inner_scope_uses_super_property_;
   }
-  // Does this scope access "this".
-  bool uses_this() const { return scope_uses_this_; }
-  // Does any inner scope access "this".
-  bool inner_uses_this() const { return inner_scope_uses_this_; }
 
   const Scope* NearestOuterEvalScope() const {
     if (is_eval_scope()) return this;
     if (outer_scope() == nullptr) return nullptr;
     return outer_scope()->NearestOuterEvalScope();
   }
 
   // ---------------------------------------------------------------------------
   // Accessors.
 
   // The type of this scope.
   ScopeType scope_type() const { return scope_type_; }
 
   FunctionKind function_kind() const { return function_kind_; }
 
   // The language mode of this scope.
   LanguageMode language_mode() const { return language_mode_; }
 
   // The variable corresponding to the 'this' value.
-  Variable* receiver() { return receiver_; }
+  Variable* receiver() {
+    DCHECK(has_this_declaration());
+    DCHECK_NOT_NULL(receiver_);
+    return receiver_;
+  }
+
+  Variable* LookupThis() { return Lookup(ast_value_factory_->this_string()); }
+
+  // TODO(wingo): Add a GLOBAL_SCOPE scope type which will lexically allocate
+  // "this" (and no other variable) on the native context.  Script scopes then
+  // will not have a "this" declaration.
+  bool has_this_declaration() const {
+    return (is_function_scope() && !is_arrow_scope()) || is_module_scope() ||
+           is_script_scope();
+  }
 
   // The variable corresponding to the 'new.target' value.
   Variable* new_target_var() { return new_target_; }
 
   // The variable holding the function literal for named function
   // literals, or NULL.  Only valid for function scopes.
   VariableDeclaration* function() const {
     DCHECK(is_function_scope());
     return function_;
   }
@@ skipping 211 matching lines @@
   bool scope_inside_with_;
   // This scope contains a 'with' statement.
   bool scope_contains_with_;
   // This scope or a nested catch scope or with scope contain an 'eval' call. At
   // the 'eval' call site this scope is the declaration scope.
   bool scope_calls_eval_;
   // This scope uses "arguments".
   bool scope_uses_arguments_;
   // This scope uses "super" property ('super.foo').
   bool scope_uses_super_property_;
-  // This scope uses "this".
-  bool scope_uses_this_;
   // This scope contains an "use asm" annotation.
   bool asm_module_;
   // This scope's outer context is an asm module.
   bool asm_function_;
   // The language mode of this scope.
   LanguageMode language_mode_;
   // Source positions.
   int start_position_;
   int end_position_;
 
   // Computed via PropagateScopeInfo.
   bool outer_scope_calls_sloppy_eval_;
   bool inner_scope_calls_eval_;
   bool inner_scope_uses_arguments_;
   bool inner_scope_uses_super_property_;
-  bool inner_scope_uses_this_;
   bool force_eager_compilation_;
   bool force_context_allocation_;
 
   // True if it doesn't need scope resolution (e.g., if the scope was
   // constructed based on a serialized scope info or a catch context).
   bool already_resolved_;
 
   // Computed as variables are declared.
   int num_var_or_const_;
 
@@ skipping 91 matching lines @@
   bool MustAllocateInContext(Variable* var);
   bool HasArgumentsParameter(Isolate* isolate);
 
   // Variable allocation.
   void AllocateStackSlot(Variable* var);
   void AllocateHeapSlot(Variable* var);
   void AllocateParameterLocals(Isolate* isolate);
   void AllocateNonParameterLocal(Isolate* isolate, Variable* var);
   void AllocateNonParameterLocals(Isolate* isolate);
   void AllocateVariablesRecursively(Isolate* isolate);
+  void AllocateParameter(Variable* var, int index);
+  void AllocateReceiver();
   void AllocateModules();
 
   // Resolve and fill in the allocation information for all variables
   // in this scopes. Must be called *after* all scopes have been
   // processed (parsed) to ensure that unresolved variables can be
   // resolved properly.
   //
   // In the case of code compiled and run using 'eval', the context
   // parameter is the context in which eval was called.  In all other
   // cases the context parameter is an empty handle.
@@ skipping 26 matching lines @@
   PendingCompilationErrorHandler pending_error_handler_;
 
   // For tracking which classes are declared consecutively. Needed for strong
   // mode.
   int class_declaration_group_start_;
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_SCOPES_H_