PPC/s390: [full-codegen] Eliminate unnecessary hole checks for stores

Port 231c8ac0

Original commit message:
  Loads already used source position elimination to avoid unnecessary hole checks,
  but for reasons unknown stores did not. This CL corrects that, making full-codegen's
  hole elimination equivalent to ignition's.

  Also introduced a HoleCheckMode enum class to avoid more bool flags and updated
  VariableProxy and BytecodeGenerator appropriately.

R=adamk@chromium.org, joransiu@ca.ibm.com, jyan@ca.ibm.com, bjaideep@ca.ibm.com, michael_dawson@ca.ibm.com, mbrandy@us.ibm.com
BUG=

Review-Url: https://codereview.chromium.org/2449473002
Cr-Commit-Position: refs/heads/master@{#40538}

src/full-codegen/ppc/full-codegen-ppc.cc

@@ -1257,7 +1257,7 @@ void FullCodeGenerator::EmitVariableLoad(VariableProxy* proxy,
       DCHECK_EQ(NOT_INSIDE_TYPEOF, typeof_mode);
       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;
@@ -1696,12 +1696,14 @@ 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(r3);
       break;
+    }
     case NAMED_PROPERTY:
       EmitNamedPropertyAssignment(expr);
       break;
@@ -2029,9 +2031,10 @@ 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: {
@@ -2106,9 +2109,9 @@ void FullCodeGenerator::EmitStoreToStackLocalOrContextSlot(
   }
 }
 
-
 void FullCodeGenerator::EmitVariableAssignment(Variable* var, Token::Value op,
-                                               FeedbackVectorSlot slot) {
+                                               FeedbackVectorSlot slot,
+                                               HoleCheckMode hole_check_mode) {
   if (var->IsUnallocated()) {
     // Global var, const, or let.
     __ LoadGlobalObject(StoreDescriptor::ReceiverRegister());
@@ -2119,7 +2122,7 @@ void FullCodeGenerator::EmitVariableAssignment(Variable* var, Token::Value op,
     DCHECK(var->IsStackAllocated() || var->IsContextSlot());
     MemOperand location = VarOperand(var, r4);
     // Perform an initialization check for lexically declared variables.
-    if (var->binding_needs_init()) {
+    if (hole_check_mode == HoleCheckMode::kRequired) {
       Label assign;
       __ LoadP(r6, location);
       __ CompareRoot(r6, Heap::kTheHoleValueRootIndex);
@@ -3187,12 +3190,13 @@ void FullCodeGenerator::VisitCountOperation(CountOperation* expr) {
 
   // Store the value returned in r3.
   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(r3);
@@ -3203,13 +3207,14 @@ 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(r3);
       }
       break;
+    }
     case NAMED_PROPERTY: {
       PopOperand(StoreDescriptor::ReceiverRegister());
       CallStoreIC(expr->CountSlot(), prop->key()->AsLiteral()->value());

src/full-codegen/s390/full-codegen-s390.cc

@@ -1221,7 +1221,7 @@ void FullCodeGenerator::EmitVariableLoad(VariableProxy* proxy,
       DCHECK_EQ(NOT_INSIDE_TYPEOF, typeof_mode);
       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;
@@ -1656,12 +1656,14 @@ 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(r2);
       break;
+    }
     case NAMED_PROPERTY:
       EmitNamedPropertyAssignment(expr);
       break;
@@ -1986,9 +1988,10 @@ 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: {
@@ -2063,7 +2066,8 @@ void FullCodeGenerator::EmitStoreToStackLocalOrContextSlot(
 }
 
 void FullCodeGenerator::EmitVariableAssignment(Variable* var, Token::Value op,
-                                               FeedbackVectorSlot slot) {
+                                               FeedbackVectorSlot slot,
+                                               HoleCheckMode hole_check_mode) {
   if (var->IsUnallocated()) {
     // Global var, const, or let.
     __ LoadGlobalObject(StoreDescriptor::ReceiverRegister());
@@ -2075,7 +2079,7 @@ void FullCodeGenerator::EmitVariableAssignment(Variable* var, Token::Value op,
     DCHECK(var->IsStackAllocated() || var->IsContextSlot());
     MemOperand location = VarOperand(var, r3);
     // Perform an initialization check for lexically declared variables.
-    if (var->binding_needs_init()) {
+    if (hole_check_mode == HoleCheckMode::kRequired) {
       Label assign;
       __ LoadP(r5, location);
       __ CompareRoot(r5, Heap::kTheHoleValueRootIndex);
@@ -3113,12 +3117,13 @@ void FullCodeGenerator::VisitCountOperation(CountOperation* expr) {
 
   // Store the value returned in r2.
   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(r2);
@@ -3129,13 +3134,14 @@ 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(r2);
       }
       break;
+    }
     case NAMED_PROPERTY: {
       PopOperand(StoreDescriptor::ReceiverRegister());
       CallStoreIC(expr->CountSlot(), prop->key()->AsLiteral()->value());