[interpreter] Simplify hole check condition for variable assignments.

src/interpreter/bytecode-generator.cc

 // Copyright 2015 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/interpreter/bytecode-generator.h"
 
 #include "src/ast/scopes.h"
 #include "src/code-stubs.h"
 #include "src/compiler.h"
 #include "src/interpreter/bytecode-flags.h"
@@ skipping 1850 matching lines @@
 }
 
 void BytecodeGenerator::VisitVariableLoad(Variable* variable,
                                           FeedbackVectorSlot slot,
                                           TypeofMode typeof_mode) {
   switch (variable->location()) {
     case VariableLocation::LOCAL: {
       Register source(Register(variable->index()));
       builder()->LoadAccumulatorWithRegister(source);
       BuildHoleCheckForVariableLoad(variable);
-      execution_result()->SetResultInAccumulator();
       break;
     }
     case VariableLocation::PARAMETER: {
       // The parameter indices are shifted by 1 (receiver is variable
       // index -1 but is parameter index 0 in BytecodeArrayBuilder).
       Register source = builder()->Parameter(variable->index() + 1);
       builder()->LoadAccumulatorWithRegister(source);
       BuildHoleCheckForVariableLoad(variable);
-      execution_result()->SetResultInAccumulator();
       break;
     }
     case VariableLocation::GLOBAL:
     case VariableLocation::UNALLOCATED: {
       builder()->LoadGlobal(feedback_index(slot), typeof_mode);
-      execution_result()->SetResultInAccumulator();
       break;
     }
     case VariableLocation::CONTEXT: {
       int depth = execution_context()->ContextChainDepth(variable->scope());
       ContextScope* context = execution_context()->Previous(depth);
       Register context_reg;
       if (context) {
         context_reg = context->reg();
       } else {
         context_reg = register_allocator()->NewRegister();
         // Walk the context chain to find the context at the given depth.
         // TODO(rmcilroy): Perform this work in a bytecode handler once we have
         // a generic mechanism for performing jumps in interpreter.cc.
         // TODO(mythria): Also update bytecode graph builder with correct depth
         // when this changes.
         builder()
             ->LoadAccumulatorWithRegister(execution_context()->reg())
             .StoreAccumulatorInRegister(context_reg);
         for (int i = 0; i < depth; ++i) {
           builder()
               ->LoadContextSlot(context_reg, Context::PREVIOUS_INDEX)
               .StoreAccumulatorInRegister(context_reg);
         }
       }
 
       builder()->LoadContextSlot(context_reg, variable->index());
       BuildHoleCheckForVariableLoad(variable);
-      execution_result()->SetResultInAccumulator();
       break;
     }
     case VariableLocation::LOOKUP: {
       builder()->LoadLookupSlot(variable->name(), typeof_mode);
-      execution_result()->SetResultInAccumulator();
       break;
     }
     case VariableLocation::MODULE:
       UNREACHABLE();
   }
+  execution_result()->SetResultInAccumulator();
 }
 
 void BytecodeGenerator::VisitVariableLoadForAccumulatorValue(
     Variable* variable, FeedbackVectorSlot slot, TypeofMode typeof_mode) {
   AccumulatorResultScope accumulator_result(this);
   VisitVariableLoad(variable, slot, typeof_mode);
 }
 
 Register BytecodeGenerator::VisitVariableLoadForRegisterValue(
     Variable* variable, FeedbackVectorSlot slot, TypeofMode typeof_mode) {
@@ skipping 93 matching lines @@
 }
 
 void BytecodeGenerator::VisitVariableAssignment(Variable* variable,
                                                 Token::Value op,
                                                 FeedbackVectorSlot slot) {
   VariableMode mode = variable->mode();
   RegisterAllocationScope assignment_register_scope(this);
   BytecodeLabel end_label;
   bool hole_check_required =
       variable->binding_needs_init() &&
-      ((IsLexicalVariableMode(mode) && op != Token::INIT) ||
-       (mode == CONST && op == Token::INIT && variable->is_this()));
+      (op != Token::INIT || (mode == CONST && variable->is_this()));
   switch (variable->location()) {
     case VariableLocation::PARAMETER:
     case VariableLocation::LOCAL: {
       Register destination;
       if (VariableLocation::PARAMETER == variable->location()) {
         destination = Register(builder()->Parameter(variable->index() + 1));
       } else {
         destination = Register(variable->index());
       }
 
@@ skipping 1235 matching lines @@
   return execution_context()->scope()->language_mode();
 }
 
 int BytecodeGenerator::feedback_index(FeedbackVectorSlot slot) const {
   return TypeFeedbackVector::GetIndex(slot);
 }
 
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8