Fix exception for assignment to uninitialised const

src/arm/full-codegen-arm.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_ARM
 
 #include "src/code-factory.h"
 #include "src/code-stubs.h"
@@ skipping 2743 matching lines @@
     __ ldr(r3, location);
     __ CompareRoot(r3, Heap::kTheHoleValueRootIndex);
     __ b(ne, &assign);
     __ mov(r3, Operand(var->name()));
     __ push(r3);
     __ CallRuntime(Runtime::kThrowReferenceError, 1);
     // Perform the assignment.
     __ bind(&assign);
     EmitStoreToStackLocalOrContextSlot(var, location);
 
+  } else if (var->mode() == CONST && op != Token::INIT_CONST) {

[Dmitry Lomov (no reviews), 2015/03/04 17:57:35]

Looks like the case at line 2800 anymore should be mode == CONST_LEGACY && op !=
INIT_CONST_LEGACY. 

Just remove IsSignallingAssignmentToConst altogether.

+    // Assignment to const variable needs a write barrier.
+    DCHECK(!var->IsLookupSlot());
+    DCHECK(var->IsStackAllocated() || var->IsContextSlot());
+    Label const_error;
+    MemOperand location = VarOperand(var, r1);
+    __ ldr(r3, location);
+    __ CompareRoot(r3, Heap::kTheHoleValueRootIndex);
+    __ b(ne, &const_error);
+    __ mov(r3, Operand(var->name()));
+    __ push(r3);
+    __ CallRuntime(Runtime::kThrowReferenceError, 1);
+    __ bind(&const_error);
+    __ CallRuntime(Runtime::kThrowConstAssignError, 0);
+
   } else if (!var->is_const_mode() || op == Token::INIT_CONST) {
     if (var->IsLookupSlot()) {
       // Assignment to var.
       __ push(r0);  // Value.
       __ mov(r1, Operand(var->name()));
       __ mov(r0, Operand(Smi::FromInt(language_mode())));
       __ Push(cp, r1, r0);  // Context, name, language mode.
       __ CallRuntime(Runtime::kStoreLookupSlot, 4);
     } else {
       // Assignment to var or initializing assignment to let/const in harmony
@@ skipping 2728 matching lines @@
 
   DCHECK(interrupt_address ==
          isolate->builtins()->OsrAfterStackCheck()->entry());
   return OSR_AFTER_STACK_CHECK;
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM