[interpreter] Unbreak test262 tests using constants.

src/interpreter/constant-array-builder.cc

 // Copyright 2015 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/interpreter/constant-array-builder.h"
 
 #include "src/isolate.h"
 #include "src/objects-inl.h"
 
 namespace v8 {
@@ skipping 69 matching lines @@
   }
   UNREACHABLE();
   return nullptr;
 }
 
 Handle<Object> ConstantArrayBuilder::At(size_t index) const {
   const ConstantArraySlice* slice = IndexToSlice(index);
   if (index < slice->start_index() + slice->size()) {
     return slice->At(index);
   } else {
+    DCHECK_LT(index, slice->capacity());
     return isolate_->factory()->the_hole_value();
   }
 }
 
 Handle<FixedArray> ConstantArrayBuilder::ToFixedArray() {
   Handle<FixedArray> fixed_array = isolate_->factory()->NewFixedArray(
       static_cast<int>(size()), PretenureFlag::TENURED);
   int array_index = 0;
   for (const ConstantArraySlice* slice : idx_slice_) {
     if (array_index == fixed_array->length()) {
       break;
     }
+    DCHECK(array_index == 0 ||
+           base::bits::IsPowerOfTwo32(static_cast<uint32_t>(array_index)));
     // Copy objects from slice into array.
     for (size_t i = 0; i < slice->size(); ++i) {
       fixed_array->set(array_index++, *slice->At(slice->start_index() + i));
     }
     // Insert holes where reservations led to unused slots.
     size_t padding =
         std::min(static_cast<size_t>(fixed_array->length() - array_index),
                  slice->capacity() - slice->size());
-    for (size_t i = slice->start_index() + slice->size();
-         i < slice->start_index() + padding; ++i) {
+    for (size_t i = 0; i < padding; i++) {
       fixed_array->set(array_index++, *isolate_->factory()->the_hole_value());
     }
   }
   DCHECK_EQ(array_index, fixed_array->length());
   constants_map()->Clear();
   return fixed_array;
 }
 
 size_t ConstantArrayBuilder::Insert(Handle<Object> object) {
   index_t* entry = constants_map()->Find(object);
@@ skipping 65 matching lines @@
   return index;
 }
 
 void ConstantArrayBuilder::DiscardReservedEntry(OperandSize operand_size) {
   OperandSizeToSlice(operand_size)->Unreserve();
 }
 
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8