Remove CONST_LEGACY VariableMode

src/full-codegen/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.
 
 #if V8_TARGET_ARCH_X64
 
 #include "src/ast/scopes.h"
 #include "src/code-factory.h"
 #include "src/code-stubs.h"
 #include "src/codegen.h"
@@ skipping 2058 matching lines @@
 
 void FullCodeGenerator::EmitVariableAssignment(Variable* var, Token::Value op,
                                                FeedbackVectorSlot slot) {
   if (var->IsUnallocated()) {
     // Global var, const, or let.
     __ Move(StoreDescriptor::NameRegister(), var->name());
     __ LoadGlobalObject(StoreDescriptor::ReceiverRegister());
     EmitLoadStoreICSlot(slot);
     CallStoreIC();
 
   } else if (IsLexicalVariableMode(var->mode()) && op != Token::INIT) {

[Toon Verwaest, 2016/08/18 07:05:26]

probably the same explicit control flow was used here?

[adamk, 2016/08/18 18:40:18]

Sort of. It wasn't as explicit (due to the fact that we share the code for
initializing assignments to LET/CONST and all assignments to VAR), so I didn't
feel like it was worth reverting.

     DCHECK(!var->IsLookupSlot());
     DCHECK(var->IsStackAllocated() || var->IsContextSlot());
     MemOperand location = VarOperand(var, rcx);
     // Perform an initialization check for lexically declared variables.
     if (var->binding_needs_init()) {
       Label assign;
       __ movp(rdx, location);
       __ CompareRoot(rdx, Heap::kTheHoleValueRootIndex);
       __ j(not_equal, &assign, Label::kNear);
       __ Push(var->name());
       __ CallRuntime(Runtime::kThrowReferenceError);
       __ bind(&assign);
     }
-    if (var->mode() == CONST) {
+    if (var->mode() != CONST) {
+      EmitStoreToStackLocalOrContextSlot(var, location);
+    } else if (var->throw_on_const_assignment(language_mode())) {
       __ CallRuntime(Runtime::kThrowConstAssignError);
-    } else {
-      EmitStoreToStackLocalOrContextSlot(var, location);
     }
 
   } else if (var->is_this() && var->mode() == CONST && op == Token::INIT) {
     // 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);
     __ bind(&uninitialized_this);
     EmitStoreToStackLocalOrContextSlot(var, location);
 
-  } else if (!var->is_const_mode() || op == Token::INIT) {
+  } else {
+    DCHECK(var->mode() != CONST || op == Token::INIT);
     if (var->IsLookupSlot()) {
       // Assignment to var.
       __ Push(var->name());
       __ Push(rax);
       __ CallRuntime(is_strict(language_mode())
                          ? Runtime::kStoreLookupSlot_Strict
                          : Runtime::kStoreLookupSlot_Sloppy);
     } else {
       // Assignment to var or initializing assignment to let/const in harmony
       // mode.
       DCHECK(var->IsStackAllocated() || var->IsContextSlot());
       MemOperand location = VarOperand(var, rcx);
       if (FLAG_debug_code && var->mode() == LET && op == Token::INIT) {
         // Check for an uninitialized let binding.
         __ movp(rdx, location);
         __ CompareRoot(rdx, Heap::kTheHoleValueRootIndex);
         __ Check(equal, kLetBindingReInitialization);
       }
       EmitStoreToStackLocalOrContextSlot(var, location);
     }
-
-  } else {
-    DCHECK(var->mode() == CONST_LEGACY && op != Token::INIT);
-    if (is_strict(language_mode())) {
-      __ CallRuntime(Runtime::kThrowConstAssignError);
-    }
-    // Silently ignore store in sloppy mode.
   }
 }
 
 
 void FullCodeGenerator::EmitNamedPropertyAssignment(Assignment* expr) {
   // Assignment to a property, using a named store IC.
   Property* prop = expr->target()->AsProperty();
   DCHECK(prop != NULL);
   DCHECK(prop->key()->IsLiteral());
 
@@ skipping 1512 matching lines @@
   DCHECK_EQ(
       isolate->builtins()->OnStackReplacement()->entry(),
       Assembler::target_address_at(call_target_address, unoptimized_code));
   return ON_STACK_REPLACEMENT;
 }
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X64