[Interpreter] Avoid allocating pairs array in VisitDeclarations.

test/unittests/interpreter/constant-array-builder-unittest.cc

 // Copyright 2014 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"
 
 #include "src/factory.h"
 #include "src/handles-inl.h"
 #include "src/interpreter/constant-array-builder.h"
 #include "src/isolate.h"
@@ skipping 25 matching lines @@
   CHECK_EQ(builder.size(), k16BitCapacity);
   for (size_t i = 0; i < k16BitCapacity; i++) {
     CHECK_EQ(Handle<Smi>::cast(builder.At(i))->value(), i);
   }
 }
 
 TEST_F(ConstantArrayBuilderTest, AllocateEntriesWithIdx8Reservations) {
   for (size_t reserved = 1; reserved < k8BitCapacity; reserved *= 3) {
     ConstantArrayBuilder builder(isolate(), zone());
     for (size_t i = 0; i < reserved; i++) {
-      OperandSize operand_size = builder.CreateReservedEntry();
+      OperandSize operand_size = builder.CreateDiscardableReservedEntry();
       CHECK(operand_size == OperandSize::kByte);
     }
     for (size_t i = 0; i < 2 * k8BitCapacity; i++) {
       Handle<Object> object = isolate()->factory()->NewNumberFromSize(i);
       builder.Insert(object);
       if (i + reserved < k8BitCapacity) {
         CHECK_LE(builder.size(), k8BitCapacity);
         CHECK_EQ(builder.size(), i + 1);
         CHECK(builder.At(i)->SameValue(*object));
       } else {
@@ skipping 30 matching lines @@
       Smi* smi = Smi::FromInt(static_cast<int>(i - reserved));
       CHECK(Handle<Smi>::cast(builder.At(i))->SameValue(smi));
     }
     for (size_t i = 0; i < reserved; i++) {
       size_t index = k8BitCapacity - reserved + i;
       CHECK(builder.At(index)->IsTheHole(isolate()));
     }
 
     // Now make reservations, and commit them with unique entries.
     for (size_t i = 0; i < duplicates_in_idx8_space; i++) {
-      OperandSize operand_size = builder.CreateReservedEntry();
+      OperandSize operand_size = builder.CreateDiscardableReservedEntry();
       CHECK(operand_size == OperandSize::kByte);
     }
     for (size_t i = 0; i < duplicates_in_idx8_space; i++) {
       Handle<Object> object =
           isolate()->factory()->NewNumberFromSize(2 * k8BitCapacity + i);
       size_t index = builder.CommitReservedEntry(OperandSize::kByte, object);
       CHECK_EQ(static_cast<int>(index), k8BitCapacity - reserved + i);
       CHECK(builder.At(static_cast<int>(index))->SameValue(*object));
     }
     CHECK_EQ(builder.size(), 2 * k8BitCapacity + reserved);
   }
 }
 
 TEST_F(ConstantArrayBuilderTest, AllocateEntriesWithWideReservations) {
   for (size_t reserved = 1; reserved < k8BitCapacity; reserved *= 3) {
     ConstantArrayBuilder builder(isolate(), zone());
     for (size_t i = 0; i < k8BitCapacity; i++) {
       Handle<Object> object = isolate()->factory()->NewNumberFromSize(i);
       builder.Insert(object);
       CHECK(builder.At(i)->SameValue(*object));
       CHECK_EQ(builder.size(), i + 1);
     }
     for (size_t i = 0; i < reserved; i++) {
-      OperandSize operand_size = builder.CreateReservedEntry();
+      OperandSize operand_size = builder.CreateDiscardableReservedEntry();
       CHECK(operand_size == OperandSize::kShort);
       CHECK_EQ(builder.size(), k8BitCapacity);
     }
     for (size_t i = 0; i < reserved; i++) {
       builder.DiscardReservedEntry(OperandSize::kShort);
       CHECK_EQ(builder.size(), k8BitCapacity);
     }
     for (size_t i = 0; i < reserved; i++) {
-      OperandSize operand_size = builder.CreateReservedEntry();
+      OperandSize operand_size = builder.CreateDiscardableReservedEntry();
       CHECK(operand_size == OperandSize::kShort);
       Handle<Object> object = isolate()->factory()->NewNumberFromSize(i);
       builder.CommitReservedEntry(operand_size, object);
       CHECK_EQ(builder.size(), k8BitCapacity);
     }
     for (size_t i = k8BitCapacity; i < k8BitCapacity + reserved; i++) {
-      OperandSize operand_size = builder.CreateReservedEntry();
+      OperandSize operand_size = builder.CreateDiscardableReservedEntry();
       CHECK(operand_size == OperandSize::kShort);
       Handle<Object> object = isolate()->factory()->NewNumberFromSize(i);
       builder.CommitReservedEntry(operand_size, object);
       CHECK_EQ(builder.size(), i + 1);
     }
   }
 }
 
 
 TEST_F(ConstantArrayBuilderTest, ToFixedArray) {
@@ skipping 22 matching lines @@
   Handle<FixedArray> constant_array = builder.ToFixedArray();
   CHECK_EQ(constant_array->length(), kNumberOfElements);
   for (size_t i = 0; i < kNumberOfElements; i++) {
     CHECK(constant_array->get(static_cast<int>(i))->SameValue(*builder.At(i)));
   }
 }
 
 TEST_F(ConstantArrayBuilderTest, GapFilledWhenLowReservationCommitted) {
   ConstantArrayBuilder builder(isolate(), zone());
   for (size_t i = 0; i < k8BitCapacity; i++) {
-    OperandSize operand_size = builder.CreateReservedEntry();
+    OperandSize operand_size = builder.CreateDiscardableReservedEntry();
     CHECK(OperandSize::kByte == operand_size);
     CHECK_EQ(builder.size(), 0);
   }
   for (size_t i = 0; i < k8BitCapacity; i++) {
     Handle<Object> object = isolate()->factory()->NewNumberFromSize(i);
     builder.Insert(object);
     CHECK_EQ(builder.size(), i + k8BitCapacity + 1);
   }
   for (size_t i = 0; i < k8BitCapacity; i++) {
     builder.CommitReservedEntry(OperandSize::kByte,
                                 builder.At(i + k8BitCapacity));
     CHECK_EQ(builder.size(), 2 * k8BitCapacity);
   }
   for (size_t i = 0; i < k8BitCapacity; i++) {
     Handle<Object> original = builder.At(k8BitCapacity + i);
     Handle<Object> duplicate = builder.At(i);
     CHECK(original->SameValue(*duplicate));
     Handle<Object> reference = isolate()->factory()->NewNumberFromSize(i);
     CHECK(original->SameValue(*reference));
   }
 }
 
 TEST_F(ConstantArrayBuilderTest, GapNotFilledWhenLowReservationDiscarded) {
   ConstantArrayBuilder builder(isolate(), zone());
   for (size_t i = 0; i < k8BitCapacity; i++) {
-    OperandSize operand_size = builder.CreateReservedEntry();
+    OperandSize operand_size = builder.CreateDiscardableReservedEntry();
     CHECK(OperandSize::kByte == operand_size);
     CHECK_EQ(builder.size(), 0);
   }
   for (size_t i = 0; i < k8BitCapacity; i++) {
     Handle<Object> object = isolate()->factory()->NewNumberFromSize(i);
     builder.Insert(object);
     CHECK_EQ(builder.size(), i + k8BitCapacity + 1);
   }
   for (size_t i = 0; i < k8BitCapacity; i++) {
     builder.DiscardReservedEntry(OperandSize::kByte);
     builder.Insert(builder.At(i + k8BitCapacity));
     CHECK_EQ(builder.size(), 2 * k8BitCapacity);
   }
   for (size_t i = 0; i < k8BitCapacity; i++) {
     Handle<Object> reference = isolate()->factory()->NewNumberFromSize(i);
     Handle<Object> original = builder.At(k8BitCapacity + i);
     CHECK(original->SameValue(*reference));
     Handle<Object> duplicate = builder.At(i);
     CHECK(duplicate->SameValue(*isolate()->factory()->the_hole_value()));
   }
 }
 
 TEST_F(ConstantArrayBuilderTest, HolesWithUnusedReservations) {
   static int kNumberOfHoles = 128;
   ConstantArrayBuilder builder(isolate(), zone());
   for (int i = 0; i < kNumberOfHoles; ++i) {
-    CHECK_EQ(builder.CreateReservedEntry(), OperandSize::kByte);
+    CHECK_EQ(builder.CreateDiscardableReservedEntry(), OperandSize::kByte);
   }
   for (int i = 0; i < 128; ++i) {
     CHECK_EQ(builder.Insert(isolate()->factory()->NewNumber(i)), i);
   }
   CHECK_EQ(builder.Insert(isolate()->factory()->NewNumber(256)), 256);
 
   Handle<FixedArray> constant_array = builder.ToFixedArray();
   CHECK_EQ(constant_array->length(), 257);
   for (int i = 128; i < 256; i++) {
     CHECK(constant_array->get(i)->SameValue(
         *isolate()->factory()->the_hole_value()));
   }
   CHECK(!constant_array->get(127)->SameValue(
       *isolate()->factory()->the_hole_value()));
   CHECK(!constant_array->get(256)->SameValue(
       *isolate()->factory()->the_hole_value()));
 }
 
 TEST_F(ConstantArrayBuilderTest, ReservationsAtAllScales) {
   ConstantArrayBuilder builder(isolate(), zone());
   for (int i = 0; i < 256; i++) {
-    CHECK_EQ(builder.CreateReservedEntry(), OperandSize::kByte);
+    CHECK_EQ(builder.CreateDiscardableReservedEntry(), OperandSize::kByte);
   }
   for (int i = 256; i < 65536; ++i) {
-    CHECK_EQ(builder.CreateReservedEntry(), OperandSize::kShort);
+    CHECK_EQ(builder.CreateDiscardableReservedEntry(), OperandSize::kShort);
   }
   for (int i = 65536; i < 131072; ++i) {
-    CHECK_EQ(builder.CreateReservedEntry(), OperandSize::kQuad);
+    CHECK_EQ(builder.CreateDiscardableReservedEntry(), OperandSize::kQuad);
   }
   CHECK_EQ(builder.CommitReservedEntry(OperandSize::kByte,
                                        isolate()->factory()->NewNumber(1)),
            0);
   CHECK_EQ(builder.CommitReservedEntry(OperandSize::kShort,
                                        isolate()->factory()->NewNumber(2)),
            256);
   CHECK_EQ(builder.CommitReservedEntry(OperandSize::kQuad,
                                        isolate()->factory()->NewNumber(3)),
            65536);
   Handle<FixedArray> constant_array = builder.ToFixedArray();
   CHECK_EQ(constant_array->length(), 65537);
   int count = 1;
   for (int i = 0; i < constant_array->length(); ++i) {
     Handle<Object> expected;
     if (i == 0 || i == 256 || i == 65536) {
       expected = isolate()->factory()->NewNumber(count++);
     } else {
       expected = isolate()->factory()->the_hole_value();
     }
     CHECK(constant_array->get(i)->SameValue(*expected));
   }
 }
 
+TEST_F(ConstantArrayBuilderTest, AllocateEntriesWithFixedReservations) {
+  ConstantArrayBuilder builder(isolate(), zone());
+  for (size_t i = 0; i < k16BitCapacity; i++) {
+    if ((i % 2) == 0) {
+      CHECK_EQ(i, builder.ReserveEntry());
+    } else {
+      builder.Insert(handle(Smi::FromInt(static_cast<int>(i)), isolate()));
+    }
+  }
+  CHECK_EQ(builder.size(), k16BitCapacity);
+
+  // Check values before reserved entries are inserted.
+  for (size_t i = 0; i < k16BitCapacity; i++) {
+    if ((i % 2) == 0) {
+      // Check reserved values are the hole.
+      Handle<Object> empty = builder.At(i);
+      CHECK(empty->SameValue(isolate()->heap()->the_hole_value()));
+    } else {
+      CHECK_EQ(Handle<Smi>::cast(builder.At(i))->value(), i);
+    }
+  }
+
+  // Insert reserved entries.
+  for (size_t i = 0; i < k16BitCapacity; i += 2) {
+    builder.InsertReservedEntry(
+        i, handle(Smi::FromInt(static_cast<int>(i)), isolate()));
+  }
+
+  // Check values after reserved entries are inserted.
+  for (size_t i = 0; i < k16BitCapacity; i++) {
+    CHECK_EQ(Handle<Smi>::cast(builder.At(i))->value(), i);
+  }
+}
+
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8