Add script context with context-allocated "const this"

src/compiler/ast-graph-builder.cc

 // Copyright 2014 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 "src/compiler/ast-graph-builder.h"
 
 #include "src/compiler.h"
 #include "src/compiler/ast-loop-assignment-analyzer.h"
 #include "src/compiler/control-builders.h"
 #include "src/compiler/js-type-feedback.h"
@@ skipping 2402 matching lines @@
   if (possibly_eval && args->length() > 0) {
     int arg_count = args->length();
 
     // Extract callee and source string from the environment.
     Node* callee = environment()->Peek(arg_count + 1);
     Node* source = environment()->Peek(arg_count - 1);
 
     // Create node to ask for help resolving potential eval call. This will
     // provide a fully resolved callee and the corresponding receiver.
     Node* function = GetFunctionClosure();
-    // TODO(wingo): ResolvePossibleDirectEval doesn't really need a receiver,
-    // now that eval scopes don't have "this" declarations.  Remove this hack
-    // once ResolvePossibleDirectEval changes.
-    Node* receiver;
-    {
-      Variable* variable = info()->scope()->LookupThis();
-      if (variable->IsStackAllocated()) {
-        receiver = environment()->Lookup(variable);
-      } else {
-        DCHECK(variable->IsContextSlot());
-        int depth = current_scope()->ContextChainLength(variable->scope());
-        bool immutable = variable->maybe_assigned() == kNotAssigned;
-        const Operator* op =
-            javascript()->LoadContext(depth, variable->index(), immutable);
-        receiver = NewNode(op, current_context());
-      }
-    }
     Node* language = jsgraph()->Constant(language_mode());
     Node* position = jsgraph()->Constant(current_scope()->start_position());
     const Operator* op =
-        javascript()->CallRuntime(Runtime::kResolvePossiblyDirectEval, 6);
-    Node* pair =
-        NewNode(op, callee, source, function, receiver, language, position);
-    PrepareFrameState(pair, expr->EvalOrLookupId(),
+        javascript()->CallRuntime(Runtime::kResolvePossiblyDirectEval, 5);
+    Node* new_callee =
+        NewNode(op, callee, source, function, language, position);
+    PrepareFrameState(new_callee, expr->EvalOrLookupId(),
                       OutputFrameStateCombine::PokeAt(arg_count + 1));
-    Node* new_callee = NewNode(common()->Projection(0), pair);
-    Node* new_receiver = NewNode(common()->Projection(1), pair);
 
-    // Patch callee and receiver on the environment.
+    // Patch callee on the environment.
     environment()->Poke(arg_count + 1, new_callee);
-    environment()->Poke(arg_count + 0, new_receiver);
   }
 
   // Create node to perform the function call.
   const Operator* call =
       javascript()->CallFunction(args->length() + 2, flags, language_mode());
   Node* value = ProcessArguments(call, args->length() + 2);
   PrepareFrameState(value, expr->id(), ast_context()->GetStateCombine());
   ast_context()->ProduceValue(value);
 }
 
@@ skipping 402 matching lines @@
   Visit(stmt->body());
 }
 
 
 void AstGraphBuilder::VisitDelete(UnaryOperation* expr) {
   Node* value;
   if (expr->expression()->IsVariableProxy()) {
     // Delete of an unqualified identifier is only allowed in classic mode but
     // deleting "this" is allowed in all language modes.
     Variable* variable = expr->expression()->AsVariableProxy()->var();
-    DCHECK(is_sloppy(language_mode()) || variable->is_this());
+    // Delete of an unqualified identifier is disallowed in strict mode but
+    // "delete this" is allowed.
+    DCHECK(is_sloppy(language_mode()) || variable->HasThisName(isolate()));
     value = BuildVariableDelete(variable, expr->id(),
                                 ast_context()->GetStateCombine());
   } else if (expr->expression()->IsProperty()) {
     Property* property = expr->expression()->AsProperty();
     VisitForValue(property->obj());
     VisitForValue(property->key());
     Node* key = environment()->Pop();
     Node* object = environment()->Pop();
     value = NewNode(javascript()->DeleteProperty(language_mode()), object, key);
     PrepareFrameState(value, expr->id(), ast_context()->GetStateCombine());
@@ skipping 427 matching lines @@
       // Global var, const, or let variable.
       Node* global = BuildLoadGlobalObject();
       Node* name = jsgraph()->Constant(variable->name());
       const Operator* op = javascript()->DeleteProperty(language_mode());
       Node* result = NewNode(op, global, name);
       PrepareFrameState(result, bailout_id, combine);
       return result;
     }
     case Variable::PARAMETER:
     case Variable::LOCAL:
-    case Variable::CONTEXT:
+    case Variable::CONTEXT: {
       // Local var, const, or let variable or context variable.
-      return jsgraph()->BooleanConstant(variable->is_this());
+      return jsgraph()->BooleanConstant(variable->HasThisName(isolate()));
+    }
     case Variable::LOOKUP: {
       // Dynamic lookup of context variable (anywhere in the chain).
       Node* name = jsgraph()->Constant(variable->name());
       const Operator* op =
           javascript()->CallRuntime(Runtime::kDeleteLookupSlot, 2);
       Node* result = NewNode(op, current_context(), name);
       PrepareFrameState(result, bailout_id, combine);
       return result;
     }
   }
@@ skipping 741 matching lines @@
     // Phi does not exist yet, introduce one.
     value = NewPhi(inputs, value, control);
     value->ReplaceInput(inputs - 1, other);
   }
   return value;
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8