Fix exception for assignment to uninitialised const

src/arm/full-codegen-arm.cc

Index: src/arm/full-codegen-arm.cc
diff --git a/src/arm/full-codegen-arm.cc b/src/arm/full-codegen-arm.cc
index d451c084771845e1b26ec6570be36d4a556934d9..ca60d2f459365295aada01e4345259ca0b4ff87d 100644
--- a/src/arm/full-codegen-arm.cc
+++ b/src/arm/full-codegen-arm.cc
@@ -2761,6 +2761,21 @@ void FullCodeGenerator::EmitVariableAssignment(Variable* var, Token::Value op) {
     __ bind(&assign);
     EmitStoreToStackLocalOrContextSlot(var, location);
 
+  } else if (var->mode() == CONST && op != Token::INIT_CONST) {
+    // 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.