Represent implicit 'this' binding by 'super' in AST.

src/x64/full-codegen-x64.cc

 // 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.
 
 #include "src/v8.h"
 
 #if V8_TARGET_ARCH_X64
 
 #include "src/code-factory.h"
 #include "src/code-stubs.h"
@@ skipping 1934 matching lines @@
   if (result_saved) {
     __ Drop(1);  // literal index
     context()->PlugTOS();
   } else {
     context()->Plug(rax);
   }
 }
 
 
 void FullCodeGenerator::VisitAssignment(Assignment* expr) {
-  DCHECK(expr->target()->IsValidReferenceExpression());
+  DCHECK(expr->target()->IsValidReferenceExpressionOrThis());
 
   Comment cmnt(masm_, "[ Assignment");
   SetExpressionPosition(expr, INSERT_BREAK);
 
   Property* property = expr->target()->AsProperty();
   LhsKind assign_type = Property::GetAssignType(property);
 
   // Evaluate LHS expression.
   switch (assign_type) {
     case VARIABLE:
@@ skipping 605 matching lines @@
       CodeFactory::BinaryOpIC(isolate(), op, strength(language_mode())).code();
   JumpPatchSite patch_site(masm_);    // unbound, signals no inlined smi code.
   CallIC(code, expr->BinaryOperationFeedbackId());
   patch_site.EmitPatchInfo();
   context()->Plug(rax);
 }
 
 
 void FullCodeGenerator::EmitAssignment(Expression* expr,
                                        FeedbackVectorICSlot slot) {
-  DCHECK(expr->IsValidReferenceExpression());
+  DCHECK(expr->IsValidReferenceExpressionOrThis());
 
   Property* prop = expr->AsProperty();
   LhsKind assign_type = Property::GetAssignType(prop);
 
   switch (assign_type) {
     case VARIABLE: {
       Variable* var = expr->AsVariableProxy()->var();
       EffectContext context(this);
       EmitVariableAssignment(var, Token::ASSIGN, slot);
       break;
@@ skipping 121 matching lines @@
     Label const_error;
     MemOperand location = VarOperand(var, rcx);
     __ movp(rdx, location);
     __ CompareRoot(rdx, Heap::kTheHoleValueRootIndex);
     __ j(not_equal, &const_error, Label::kNear);
     __ Push(var->name());
     __ CallRuntime(Runtime::kThrowReferenceError, 1);
     __ bind(&const_error);
     __ CallRuntime(Runtime::kThrowConstAssignError, 0);
 
+  } else if (var->is_this() && op == Token::INIT_CONST) {
+    // Initializing assignment to const {this} needs a write barrier.
+    DCHECK(var->IsStackAllocated() || var->IsContextSlot());
+    Label uninitialized_this;
+    MemOperand location = VarOperand(var, rcx);
+    __ movp(rdx, location);
+    __ CompareRoot(rdx, Heap::kTheHoleValueRootIndex);
+    __ j(equal, &uninitialized_this);
+    __ Push(var->name());
+    __ CallRuntime(Runtime::kThrowReferenceError, 1);
+    __ bind(&uninitialized_this);
+    EmitStoreToStackLocalOrContextSlot(var, location);
+
   } else if (!var->is_const_mode() || op == Token::INIT_CONST) {
     if (var->IsLookupSlot()) {
       // Assignment to var.
       __ Push(rax);  // Value.
       __ Push(rsi);  // Context.
       __ Push(var->name());
       __ Push(Smi::FromInt(language_mode()));
       __ CallRuntime(Runtime::kStoreLookupSlot, 4);
     } else {
       // Assignment to var or initializing assignment to let/const in harmony
@@ skipping 321 matching lines @@
   __ Push(Smi::FromInt(language_mode()));
 
   // Push the start position of the scope the calls resides in.
   __ Push(Smi::FromInt(scope()->start_position()));
 
   // Do the runtime call.
   __ CallRuntime(Runtime::kResolvePossiblyDirectEval, 5);
 }
 
 
-void FullCodeGenerator::EmitInitializeThisAfterSuper(
-    SuperCallReference* super_ref, FeedbackVectorICSlot slot) {
-  Variable* this_var = super_ref->this_var()->var();
-  GetVar(rcx, this_var);
-  __ CompareRoot(rcx, Heap::kTheHoleValueRootIndex);
-  Label uninitialized_this;
-  __ j(equal, &uninitialized_this);
-  __ Push(this_var->name());
-  __ CallRuntime(Runtime::kThrowReferenceError, 1);
-  __ bind(&uninitialized_this);
-
-  EmitVariableAssignment(this_var, Token::INIT_CONST, slot);
-}
-
-
 // See http://www.ecma-international.org/ecma-262/6.0/#sec-function-calls.
 void FullCodeGenerator::PushCalleeAndWithBaseObject(Call* expr) {
   VariableProxy* callee = expr->expression()->AsVariableProxy();
   if (callee->var()->IsLookupSlot()) {
     Label slow, done;
     SetExpressionPosition(callee);
     // Generate code for loading from variables potentially shadowed by
     // eval-introduced variables.
     EmitDynamicLookupFastCase(callee, NOT_INSIDE_TYPEOF, &slow, &done);
     __ bind(&slow);
@@ skipping 194 matching lines @@
   }
 
   __ Move(rbx, FeedbackVector());
   __ Move(rdx, SmiFromSlot(expr->CallFeedbackSlot()));
 
   CallConstructStub stub(isolate(), SUPER_CALL_RECORD_TARGET);
   __ call(stub.GetCode(), RelocInfo::CONSTRUCT_CALL);
 
   RecordJSReturnSite(expr);
 
-  EmitInitializeThisAfterSuper(super_call_ref, expr->CallFeedbackICSlot());
   context()->Plug(rax);
 }
 
 
 void FullCodeGenerator::EmitIsSmi(CallRuntime* expr) {
   ZoneList<Expression*>* args = expr->arguments();
   DCHECK(args->length() == 1);
 
   VisitForAccumulatorValue(args->at(0));
 
@@ skipping 1381 matching lines @@
 
   // Push NewTarget
   DCHECK(args->at(2)->IsVariableProxy());
   VisitForStackValue(args->at(2));
 
   EmitCallJSRuntimeFunction(call);
 
   // Restore context register.
   __ movp(rsi, Operand(rbp, StandardFrameConstants::kContextOffset));
   context()->DropAndPlug(1, rax);
-
-  // TODO(mvstanton): with FLAG_vector_stores this needs a slot id.
-  EmitInitializeThisAfterSuper(super_call_ref);
 }
 
 
 void FullCodeGenerator::EmitLoadJSRuntimeFunction(CallRuntime* expr) {
   // Push the builtins object as receiver.
   __ movp(rax, GlobalObjectOperand());
   __ Push(FieldOperand(rax, GlobalObject::kBuiltinsOffset));
 
   // Load the function from the receiver.
   __ movp(LoadDescriptor::ReceiverRegister(), Operand(rsp, 0));
@@ skipping 179 matching lines @@
       break;
     }
 
     default:
       UNREACHABLE();
   }
 }
 
 
 void FullCodeGenerator::VisitCountOperation(CountOperation* expr) {
-  DCHECK(expr->expression()->IsValidReferenceExpression());
+  DCHECK(expr->expression()->IsValidReferenceExpressionOrThis());
 
   Comment cmnt(masm_, "[ CountOperation");
 
   Property* prop = expr->expression()->AsProperty();
   LhsKind assign_type = Property::GetAssignType(prop);
 
   // Evaluate expression and get value.
   if (assign_type == VARIABLE) {
     DCHECK(expr->expression()->AsVariableProxy()->var() != NULL);
     AccumulatorValueContext context(this);
@@ skipping 609 matching lines @@
             Assembler::target_address_at(call_target_address,
                                          unoptimized_code));
   return OSR_AFTER_STACK_CHECK;
 }
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X64