[full-codegen] Eliminate unnecessary hole checks for stores

src/full-codegen/arm64/full-codegen-arm64.cc

Index: src/full-codegen/arm64/full-codegen-arm64.cc
diff --git a/src/full-codegen/arm64/full-codegen-arm64.cc b/src/full-codegen/arm64/full-codegen-arm64.cc
index 4ed88b4e6fd630cd78806157178ac94d68716413..2e3b95898eb1eddeabc49f4e64d3141ab61f4f66 100644
--- a/src/full-codegen/arm64/full-codegen-arm64.cc
+++ b/src/full-codegen/arm64/full-codegen-arm64.cc
@@ -1275,7 +1275,7 @@ void FullCodeGenerator::EmitVariableLoad(VariableProxy* proxy,
       Comment cmnt(masm_, var->IsContextSlot()
                               ? "Context variable"
                               : "Stack variable");
-      if (proxy->needs_hole_check()) {
+      if (proxy->hole_check_mode() == HoleCheckMode::kRequired) {
         // Throw a reference error when using an uninitialized let/const
         // binding in harmony mode.
         Label done;
@@ -1710,12 +1710,14 @@ void FullCodeGenerator::VisitAssignment(Assignment* expr) {
 
   // Store the value.
   switch (assign_type) {
-    case VARIABLE:
-      EmitVariableAssignment(expr->target()->AsVariableProxy()->var(),
-                             expr->op(), expr->AssignmentSlot());
+    case VARIABLE: {
+      VariableProxy* proxy = expr->target()->AsVariableProxy();
+      EmitVariableAssignment(proxy->var(), expr->op(), expr->AssignmentSlot(),
+                             proxy->hole_check_mode());
       PrepareForBailoutForId(expr->AssignmentId(), BailoutState::TOS_REGISTER);
       context()->Plug(x0);
       break;
+    }
     case NAMED_PROPERTY:
       EmitNamedPropertyAssignment(expr);
       break;
@@ -1908,9 +1910,10 @@ void FullCodeGenerator::EmitAssignment(Expression* expr,
 
   switch (assign_type) {
     case VARIABLE: {
-      Variable* var = expr->AsVariableProxy()->var();
+      VariableProxy* proxy = expr->AsVariableProxy();
       EffectContext context(this);
-      EmitVariableAssignment(var, Token::ASSIGN, slot);
+      EmitVariableAssignment(proxy->var(), Token::ASSIGN, slot,
+                             proxy->hole_check_mode());
       break;
     }
     case NAMED_PROPERTY: {
@@ -1987,9 +1990,9 @@ void FullCodeGenerator::EmitStoreToStackLocalOrContextSlot(
   }
 }
 
-
 void FullCodeGenerator::EmitVariableAssignment(Variable* var, Token::Value op,
-                                               FeedbackVectorSlot slot) {
+                                               FeedbackVectorSlot slot,
+                                               HoleCheckMode hole_check_mode) {
   ASM_LOCATION("FullCodeGenerator::EmitVariableAssignment");
   if (var->IsUnallocated()) {
     // Global var, const, or let.
@@ -3106,11 +3109,12 @@ void FullCodeGenerator::VisitCountOperation(CountOperation* expr) {
 
   // Store the value returned in x0.
   switch (assign_type) {
-    case VARIABLE:
+    case VARIABLE: {
+      VariableProxy* proxy = expr->expression()->AsVariableProxy();
       if (expr->is_postfix()) {
         { EffectContext context(this);
-          EmitVariableAssignment(expr->expression()->AsVariableProxy()->var(),
-                                 Token::ASSIGN, expr->CountSlot());
+          EmitVariableAssignment(proxy->var(), Token::ASSIGN, expr->CountSlot(),
+                                 proxy->hole_check_mode());
           PrepareForBailoutForId(expr->AssignmentId(),
                                  BailoutState::TOS_REGISTER);
           context.Plug(x0);
@@ -3121,13 +3125,14 @@ void FullCodeGenerator::VisitCountOperation(CountOperation* expr) {
           context()->PlugTOS();
         }
       } else {
-        EmitVariableAssignment(expr->expression()->AsVariableProxy()->var(),
-                               Token::ASSIGN, expr->CountSlot());
+        EmitVariableAssignment(proxy->var(), Token::ASSIGN, expr->CountSlot(),
+                               proxy->hole_check_mode());
         PrepareForBailoutForId(expr->AssignmentId(),
                                BailoutState::TOS_REGISTER);
         context()->Plug(x0);
       }
       break;
+    }
     case NAMED_PROPERTY: {
       PopOperand(StoreDescriptor::ReceiverRegister());
       CallStoreIC(expr->CountSlot(), prop->key()->AsLiteral()->value());