Remove concept of virtualization level

But for a single place in test-db, we used virtualization level 0 for
non-virtualized cells and level 1 for virtualized ones. With this patch,
we do not store this level anymore and instead infer it based on
"effective" level (previously known as VirtualizationParameters::level)
and the actual level of the cell.

This is mainly done to reduce cognitive complexity of the code. However,
as a nice side-effect, changes in VirtualCell give a negligible
performance improvement on the verification benchmark.

Author: DanShaders

blockchain-explorer/blockchain-explorer-http.cpp

@@ -366,7 +366,7 @@ HttpAnswer& HttpAnswer::operator<<(AccountCell acc_c) {
   last_trans_hash.set_zero();
   block::CurrencyCollection balance = block::CurrencyCollection::zero();
   try {
-    auto state_root = vm::MerkleProof::virtualize(acc_c.q_roots[1], 1);
+    auto state_root = vm::MerkleProof::virtualize(acc_c.q_roots[1]);
     if (state_root.is_null()) {
       abort("account state proof is invalid");
       return *this;
@@ -474,7 +474,7 @@ HttpAnswer& HttpAnswer::operator<<(BlockHeaderCell head_c) {
   vm::CellSlice cs{vm::NoVm(), head_c.root};
   auto block_id = head_c.block_id;
   try {
-    auto virt_root = vm::MerkleProof::virtualize(head_c.root, 1);
+    auto virt_root = vm::MerkleProof::virtualize(head_c.root);
     if (virt_root.is_null()) {
       abort("invalid merkle proof");
       return *this;

crypto/CMakeLists.txt

@@ -78,7 +78,6 @@ set(TON_CRYPTO_CORE_SOURCE
   vm/cells/PrunnedCell.h
   vm/cells/UsageCell.h
   vm/cells/VirtualCell.h
-  vm/cells/VirtualizationParameters.h
 
   vm/cells.h
   vm/cellslice.h

crypto/block/check-proof.cpp

@@ -73,7 +73,7 @@ td::Status check_block_header_proof(td::Ref<vm::Cell> root, ton::BlockIdExt blki
 
 td::Result<td::Bits256> check_state_proof(ton::BlockIdExt blkid, td::Slice proof) {
   TRY_RESULT(proof_root, vm::std_boc_deserialize(proof));
-  auto virt_root = vm::MerkleProof::virtualize(std::move(proof_root), 1);
+  auto virt_root = vm::MerkleProof::virtualize(std::move(proof_root));
   if (virt_root.is_null()) {
     return td::Status::Error("account state proof is invalid");
   }
@@ -86,7 +86,7 @@ td::Result<Ref<vm::Cell>> check_extract_state_proof(ton::BlockIdExt blkid, td::S
   try {
     TRY_RESULT(state_hash, check_state_proof(blkid, proof));
     TRY_RESULT(state_root, vm::std_boc_deserialize(data));
-    auto state_virt_root = vm::MerkleProof::virtualize(std::move(state_root), 1);
+    auto state_virt_root = vm::MerkleProof::virtualize(std::move(state_root));
     if (state_virt_root.is_null()) {
       return td::Status::Error("account state proof is invalid");
     }
@@ -118,13 +118,13 @@ td::Status check_shard_proof(ton::BlockIdExt blk, ton::BlockIdExt shard_blk, td:
     return td::Status::Error("shard configuration proof must have exactly two roots");
   }
   try {
-    auto mc_state_root = vm::MerkleProof::virtualize(std::move(P_roots[1]), 1);
+    auto mc_state_root = vm::MerkleProof::virtualize(std::move(P_roots[1]));
     if (mc_state_root.is_null()) {
       return td::Status::Error("shard configuration proof is invalid");
     }
     ton::Bits256 mc_state_hash = mc_state_root->get_hash().bits();
     TRY_STATUS_PREFIX(
-        check_block_header_proof(vm::MerkleProof::virtualize(std::move(P_roots[0]), 1), blk, &mc_state_hash, true),
+        check_block_header_proof(vm::MerkleProof::virtualize(std::move(P_roots[0])), blk, &mc_state_hash, true),
         "error in shard configuration block header proof :");
     block::gen::ShardStateUnsplit::Record sstate;
     if (!(tlb::unpack_cell(mc_state_root, sstate))) {
@@ -171,12 +171,12 @@ td::Status check_account_proof(td::Slice proof, ton::BlockIdExt shard_blk, const
   }
 
   try {
-    auto state_root = vm::MerkleProof::virtualize(std::move(Q_roots[1]), 1);
+    auto state_root = vm::MerkleProof::virtualize(std::move(Q_roots[1]));
     if (state_root.is_null()) {
       return td::Status::Error("account state proof is invalid");
     }
     ton::Bits256 state_hash = state_root->get_hash().bits();
-    TRY_STATUS_PREFIX(check_block_header_proof(vm::MerkleProof::virtualize(std::move(Q_roots[0]), 1), shard_blk,
+    TRY_STATUS_PREFIX(check_block_header_proof(vm::MerkleProof::virtualize(std::move(Q_roots[0])), shard_blk,
                                                &state_hash, true, save_utime, save_lt),
                       "error in account shard block header proof : ");
     block::gen::ShardStateUnsplit::Record sstate;
@@ -223,7 +223,7 @@ td::Result<AccountState::Info> AccountState::validate(ton::BlockIdExt ref_blk, b
   Ref<vm::Cell> root;
 
   if (is_virtualized && true_root.not_null()) {
-    root = vm::MerkleProof::virtualize(true_root, 1);
+    root = vm::MerkleProof::virtualize(true_root);
     if (root.is_null()) {
       return td::Status::Error("account state proof is invalid");
     }
@@ -346,7 +346,7 @@ td::Result<BlockTransactionList::Info> BlockTransactionList::validate(bool check
   if (check_proof) {
     try {
       TRY_RESULT(proof_cell, vm::std_boc_deserialize(std::move(proof_boc)));
-      auto virt_root = vm::MerkleProof::virtualize(proof_cell, 1);
+      auto virt_root = vm::MerkleProof::virtualize(proof_cell);
 
       if (blkid.root_hash != virt_root->get_hash().bits()) {
         return td::Status::Error("Invalid block proof root hash");
@@ -452,15 +452,15 @@ td::Status BlockProofLink::validate(td::uint32* save_utime) const {
   }
   try {
     // virtualize Merkle proof roots
-    auto vs_root = vm::MerkleProof::virtualize(proof, 1);
+    auto vs_root = vm::MerkleProof::virtualize(proof);
     if (vs_root.is_null()) {
       return td::Status::Error("BlockProofLink contains an invalid Merkle proof for source block "s + from.to_str());
     }
     ton::Bits256 state_hash;
     if (from.seqno()) {
       TRY_STATUS(check_block_header(vs_root, from, is_fwd ? nullptr : &state_hash));
     }
-    auto vd_root = dest_proof.not_null() ? vm::MerkleProof::virtualize(dest_proof, 1) : Ref<vm::Cell>{};
+    auto vd_root = dest_proof.not_null() ? vm::MerkleProof::virtualize(dest_proof) : Ref<vm::Cell>{};
     if (vd_root.is_null() && to.seqno()) {
       return td::Status::Error("BlockProofLink contains an invalid Merkle proof for destination block "s + to.to_str());
     }
@@ -483,7 +483,7 @@ td::Status BlockProofLink::validate(td::uint32* save_utime) const {
     }
     if (!is_fwd) {
       // check a backward link
-      auto vstate_root = vm::MerkleProof::virtualize(state_proof, 1);
+      auto vstate_root = vm::MerkleProof::virtualize(state_proof);
       if (vstate_root.is_null()) {
         return td::Status::Error("backward BlockProofLink contains an invalid Merkle proof for source state "s +
                                  from.to_str());

crypto/test/test-db.cpp

@@ -663,13 +663,13 @@ TEST(Cell, MerkleProof) {
     auto proof = MerkleProof::generate(cell, is_prunned);
     // CellBuilder::virtualize(proof, 1);
     //ASSERT_EQ(1u, proof->get_level());
-    auto virtualized_proof = MerkleProof::virtualize(proof, 1);
+    auto virtualized_proof = MerkleProof::virtualize(proof);
     auto exploration3 = CellExplorer::explore(virtualized_proof, exploration.ops);
     ASSERT_EQ(exploration.log, exploration3.log);
 
     auto proof2 = MerkleProof::generate(cell, usage_tree.get());
     CHECK(proof2->get_depth() == proof->get_depth());
-    auto virtualized_proof2 = MerkleProof::virtualize(proof2, 1);
+    auto virtualized_proof2 = MerkleProof::virtualize(proof2);
     auto exploration4 = CellExplorer::explore(virtualized_proof2, exploration.ops);
     ASSERT_EQ(exploration.log, exploration4.log);
   }
@@ -690,7 +690,7 @@ TEST(Cell, MerkleProofCombine) {
       CellExplorer::explore(usage_cell, exploration1.ops);
       proof1 = MerkleProof::generate(cell, usage_tree.get());
 
-      auto virtualized_proof = MerkleProof::virtualize(proof1, 1);
+      auto virtualized_proof = MerkleProof::virtualize(proof1);
       auto exploration = CellExplorer::explore(virtualized_proof, exploration1.ops);
       ASSERT_EQ(exploration.log, exploration1.log);
     }
@@ -702,7 +702,7 @@ TEST(Cell, MerkleProofCombine) {
       CellExplorer::explore(usage_cell, exploration2.ops);
       proof2 = MerkleProof::generate(cell, usage_tree.get());
 
-      auto virtualized_proof = MerkleProof::virtualize(proof2, 1);
+      auto virtualized_proof = MerkleProof::virtualize(proof2);
       auto exploration = CellExplorer::explore(virtualized_proof, exploration2.ops);
       ASSERT_EQ(exploration.log, exploration2.log);
     }
@@ -715,7 +715,7 @@ TEST(Cell, MerkleProofCombine) {
       CellExplorer::explore(usage_cell, exploration2.ops);
       proof12 = MerkleProof::generate(cell, usage_tree.get());
 
-      auto virtualized_proof = MerkleProof::virtualize(proof12, 1);
+      auto virtualized_proof = MerkleProof::virtualize(proof12);
       auto exploration_a = CellExplorer::explore(virtualized_proof, exploration1.ops);
       auto exploration_b = CellExplorer::explore(virtualized_proof, exploration2.ops);
       ASSERT_EQ(exploration_a.log, exploration1.log);
@@ -724,7 +724,7 @@ TEST(Cell, MerkleProofCombine) {
 
     {
       auto check = [&](auto proof_union) {
-        auto virtualized_proof = MerkleProof::virtualize(proof_union, 1);
+        auto virtualized_proof = MerkleProof::virtualize(proof_union);
         auto exploration_a = CellExplorer::explore(virtualized_proof, exploration1.ops);
         auto exploration_b = CellExplorer::explore(virtualized_proof, exploration2.ops);
         ASSERT_EQ(exploration_a.log, exploration1.log);
@@ -738,14 +738,14 @@ TEST(Cell, MerkleProofCombine) {
       check(proof_union_fast);
     }
     {
-      cell = MerkleProof::virtualize(proof12, 1);
+      cell = MerkleProof::virtualize(proof12);
 
       auto usage_tree = std::make_shared<CellUsageTree>();
       auto usage_cell = UsageCell::create(cell, usage_tree->root_ptr());
       CellExplorer::explore(usage_cell, exploration1.ops);
       auto proof = MerkleProof::generate(cell, usage_tree.get());
 
-      auto virtualized_proof = MerkleProof::virtualize(proof, 2);
+      auto virtualized_proof = MerkleProof::virtualize(proof);
       auto exploration = CellExplorer::explore(virtualized_proof, exploration1.ops);
       ASSERT_EQ(exploration.log, exploration1.log);
       if (proof->get_hash() != proof1->get_hash()) {
@@ -2152,28 +2152,28 @@ TEST(Cell, MerkleProofHands) {
   test_boc_deserializer_full(merkle_proof).ensure();
 
   {
-    auto virtual_node = proof->virtualize({0, 1});
+    auto virtual_node = proof->virtualize(0);
     ASSERT_EQ(0u, virtual_node->get_level());
-    ASSERT_EQ(1u, virtual_node->get_virtualization());
+    ASSERT_EQ(1u, virtual_node->is_virtualized());
     CellSlice cs{NoVm(), virtual_node};
     auto virtual_data = cs.fetch_ref();
     ASSERT_EQ(0u, virtual_data->get_level());
-    ASSERT_EQ(1u, virtual_data->get_virtualization());
+    ASSERT_EQ(1u, virtual_data->is_virtualized());
     ASSERT_EQ(data->get_hash(), virtual_data->get_hash());
 
     auto virtual_node_copy =
         CellBuilder{}.store_bits(node->get_data(), node->get_bits()).store_ref(virtual_data).finalize();
     ASSERT_EQ(0u, virtual_node_copy->get_level());
-    ASSERT_EQ(1u, virtual_node_copy->get_virtualization());
+    ASSERT_EQ(1u, virtual_node_copy->is_virtualized());
     ASSERT_EQ(virtual_node->get_hash(), virtual_node_copy->get_hash());
 
     {
       auto two_nodes = CellBuilder{}.store_ref(virtual_node).store_ref(node).finalize();
       ASSERT_EQ(0u, two_nodes->get_level());
-      ASSERT_EQ(1u, two_nodes->get_virtualization());
+      ASSERT_EQ(1u, two_nodes->is_virtualized());
       CellSlice cs2(NoVm(), two_nodes);
-      ASSERT_EQ(1u, cs2.prefetch_ref(0)->get_virtualization());
-      ASSERT_EQ(0u, cs2.prefetch_ref(1)->get_virtualization());
+      ASSERT_EQ(1u, cs2.prefetch_ref(0)->is_virtualized());
+      ASSERT_EQ(0u, cs2.prefetch_ref(1)->is_virtualized());
     }
   }
   LOG(ERROR) << td::NamedThreadSafeCounter::get_default();
@@ -2195,7 +2195,7 @@ TEST(Cell, MerkleProofArrayHands) {
   ASSERT_TRUE(proof->get_hash(1) != arr.root()->get_hash(1));
   ASSERT_EQ(arr.root()->get_hash(0), arr.root()->get_hash(1));
 
-  CompactArray new_arr(arr.size(), proof->virtualize({0, 1}));
+  CompactArray new_arr(arr.size(), proof->virtualize(0));
   for (auto k : keys) {
     ASSERT_EQ(arr.get(k), new_arr.get(k));
   }
@@ -2222,7 +2222,7 @@ TEST(Cell, MerkleProofCombineArray) {
     }
   }
 
-  CompactArray arr2(n, vm::MerkleProof::virtualize(root, 1));
+  CompactArray arr2(n, vm::MerkleProof::virtualize(root));
   for (size_t i = 0; i < n; i++) {
     CHECK(arr.get(i) == arr2.get(i));
   }
@@ -2920,7 +2920,7 @@ TEST(TonDb, BocRespectsUsageCell) {
   auto usage_cell = vm::UsageCell::create(cell, usage_tree->root_ptr());
   auto serialization = serialize_boc(usage_cell);
   auto proof = vm::MerkleProof::generate(cell, usage_tree.get());
-  auto virtualized_proof = vm::MerkleProof::virtualize(proof, 1);
+  auto virtualized_proof = vm::MerkleProof::virtualize(proof);
   auto serialization_of_virtualized_cell = serialize_boc(virtualized_proof);
   ASSERT_STREQ(serialization, serialization_of_virtualized_cell);
 }
@@ -2946,7 +2946,7 @@ TEST(UsageTree, ThreadSafe) {
       thread.join();
     }
     auto proof = vm::MerkleProof::generate(cell, usage_tree.get());
-    auto virtualized_proof = vm::MerkleProof::virtualize(proof, 1);
+    auto virtualized_proof = vm::MerkleProof::virtualize(proof);
     for (auto &exploration : explorations) {
       auto new_exploration = vm::CellExplorer::explore(virtualized_proof, exploration.ops);
       ASSERT_EQ(exploration.log, new_exploration.log);
@@ -3024,8 +3024,8 @@ TEST(TonDb, DoNotMakeListsPrunned) {
   auto cell = vm::CellBuilder().store_bytes("abc").finalize();
   auto is_prunned = [&](const td::Ref<vm::Cell> &cell) { return true; };
   auto proof = vm::MerkleProof::generate(cell, is_prunned);
-  auto virtualized_proof = vm::MerkleProof::virtualize(proof, 1);
-  ASSERT_TRUE(virtualized_proof->get_virtualization() == 0);
+  auto virtualized_proof = vm::MerkleProof::virtualize(proof);
+  ASSERT_TRUE(!virtualized_proof->is_virtualized());
 }
 
 TEST(TonDb, CellStat) {

crypto/vm/boc.cpp

@@ -163,7 +163,7 @@ int BagOfCells::add_root(td::Ref<vm::Cell> add_root) {
   if (add_root.is_null()) {
     return 0;
   }
-  LOG_CHECK(add_root->get_virtualization() == 0) << "TODO: support serialization of virtualized cells";
+  LOG_CHECK(!add_root->is_virtualized()) << "TODO: support serialization of virtualized cells";
   //const Cell::Hash& hash = add_root->get_hash();
   //for (const auto& root_info : roots) {
   //if (root_info.cell->get_hash() == hash) {
@@ -217,7 +217,7 @@ td::Result<int> BagOfCells::import_cell(td::Ref<vm::Cell> cell, int depth) {
     cell_list_[pos].should_cache = true;
     return pos;
   }
-  if (cell->get_virtualization() != 0) {
+  if (cell->is_virtualized()) {
     return td::Status::Error(
         "error while importing a cell into a bag of cells: cell has non-zero virtualization level");
   }

crypto/vm/cells/Cell.cpp

@@ -48,8 +48,8 @@ td::Status Cell::check_equals_unloaded(const Ref<Cell>& other) const {
   return td::Status::OK();
 }
 
-Ref<Cell> Cell::virtualize(VirtualizationParameters virt) const {
-  return VirtualCell::create(virt, Ref<Cell>(this));
+Ref<Cell> Cell::virtualize(td::uint32 effective_level) const {
+  return VirtualCell::create(effective_level, Ref<Cell>(this));
 }
 
 std::ostream& operator<<(std::ostream& os, const Cell& c) {

crypto/vm/cells/Cell.h

@@ -25,7 +25,6 @@
 #include "vm/cells/CellTraits.h"
 #include "vm/cells/CellUsageTree.h"
 #include "vm/cells/LevelMask.h"
-#include "vm/cells/VirtualizationParameters.h"
 
 #include "td/utils/Status.h"
 
@@ -38,10 +37,9 @@ class DataCell;
 class Cell : public CellTraits {
  public:
   using LevelMask = detail::LevelMask;
-  using VirtualizationParameters = detail::VirtualizationParameters;
   struct LoadedCell {
     Ref<DataCell> data_cell;
-    VirtualizationParameters virt;
+    td::uint32 effective_level;
     CellUsageTree::NodePtr tree_node;  // TODO: inline_vector?
   };
 
@@ -57,8 +55,9 @@ class Cell : public CellTraits {
   // load interface
   virtual td::Status set_data_cell(Ref<DataCell> &&data_cell) const = 0;
   virtual td::Result<LoadedCell> load_cell() const = 0;
-  virtual Ref<Cell> virtualize(VirtualizationParameters virt) const;
-  virtual td::uint32 get_virtualization() const = 0;
+  virtual Ref<Cell> virtualize(td::uint32 effective_level) const;
+  // Cell is virtualized if its effective level is less than its actual level.
+  virtual bool is_virtualized() const = 0;
   virtual CellUsageTree::NodePtr get_tree_node() const = 0;
   virtual bool is_loaded() const = 0;
 

crypto/vm/cells/CellBuilder.cpp

@@ -100,7 +100,7 @@ Ref<DataCell> CellBuilder::finalize(bool special) {
 }
 
 Ref<Cell> CellBuilder::create_pruned_branch(Ref<Cell> cell, td::uint32 new_level, td::uint32 virt_level) {
-  if (cell->is_loaded() && cell->get_level() <= virt_level && cell->get_virtualization() == 0) {
+  if (cell->is_loaded() && cell->get_level() <= virt_level && !cell->is_virtualized()) {
     CellSlice cs(NoVm{}, cell);
     if (cs.size_refs() == 0) {
       return cell;