Use unaligned read/write for page labels, fix ubsan failures

14 files changed, 101 insertions, 92 deletions

diff --git a/ydb/core/tablet_flat/flat_bloom_writer.h b/ydb/core/tablet_flat/flat_bloom_writer.h
index 9884d602dd6..b0b91f01b6c 100644
--- a/ydb/core/tablet_flat/flat_bloom_writer.h
+++ b/ydb/core/tablet_flat/flat_bloom_writer.h
@@ -81,11 +81,8 @@ namespace NBloom {
 
             NUtil::NBin::TPut out(Raw.mutable_begin());
 
-            if (auto *hdr = out.Skip<NPage::TLabel>()) {
-                hdr->Type = NPage::EPage::Bloom;
-                hdr->Format = 0;
-                hdr->Size = size;
-            }
+            WriteUnaligned<NPage::TLabel>(out.Skip<NPage::TLabel>(),
+                NPage::TLabel::Encode(NPage::EPage::Bloom, 0, size));
 
             if (auto *post = out.Skip<THeader>()) {
                 Zero(*post);
diff --git a/ydb/core/tablet_flat/flat_page_data.h b/ydb/core/tablet_flat/flat_page_data.h
index a37c4bf75ba..cef621b3f2e 100644
--- a/ydb/core/tablet_flat/flat_page_data.h
+++ b/ydb/core/tablet_flat/flat_page_data.h
@@ -175,9 +175,9 @@ namespace NPage {
             Set(raw);
         }
 
-        const auto* Label() const noexcept
+        NPage::TLabel Label() const noexcept
         {
-            return TDeref<const NPage::TLabel>::At(Raw.data());
+            return ReadUnaligned<NPage::TLabel>(Raw.data());
         }
 
         explicit operator bool() const noexcept
diff --git a/ydb/core/tablet_flat/flat_page_gstat.h b/ydb/core/tablet_flat/flat_page_gstat.h
index d5eff46141c..6890ba3151d 100644
--- a/ydb/core/tablet_flat/flat_page_gstat.h
+++ b/ydb/core/tablet_flat/flat_page_gstat.h
@@ -211,9 +211,7 @@ namespace NPage {
 
             NUtil::NBin::TPut out(buf.mutable_begin());
 
-            if (auto* label = out.Skip<NPage::TLabel>()) {
-                label->Init(EPage::GarbageStats, 0, pageSize);
-            }
+            WriteUnaligned<TLabel>(out.Skip<TLabel>(), TLabel::Encode(EPage::GarbageStats, 0, pageSize));
 
             if (auto* header = out.Skip<THeader>()) {
                 Zero(*header);
diff --git a/ydb/core/tablet_flat/flat_page_index.h b/ydb/core/tablet_flat/flat_page_index.h
index c0b50a5843c..49ee1d9aa43 100644
--- a/ydb/core/tablet_flat/flat_page_index.h
+++ b/ydb/core/tablet_flat/flat_page_index.h
@@ -85,9 +85,9 @@ namespace NPage {
             return &Page;
         }
 
-        const auto* Label() const noexcept
+        NPage::TLabel Label() const noexcept
         {
-            return TDeref<const NPage::TLabel>::At(Raw.data(), 0);
+            return ReadUnaligned<NPage::TLabel>(Raw.data());
         }
 
         TIter Rewind(TRowId to, TIter on, int dir) const
diff --git a/ydb/core/tablet_flat/flat_page_label.cpp b/ydb/core/tablet_flat/flat_page_label.cpp
index 894722e1f3d..9cfe54b64dc 100644
--- a/ydb/core/tablet_flat/flat_page_label.cpp
+++ b/ydb/core/tablet_flat/flat_page_label.cpp
@@ -2,59 +2,47 @@
 #include "util_deref.h"
 
 #include <util/system/sanitizers.h>
+#include <util/system/unaligned_mem.h>
 
 namespace NKikimr {
 namespace NTable {
 namespace NPage {
 
-    void TLabel::Init(EPage type, ui16 format, ui64 size) noexcept {
-        Type = type;
-        Format = format;
-        SetSize(size);
-    }
-
-    void TLabel::SetSize(ui64 size) noexcept {
-        // We use Max<ui32>() as a huge (>=4GB) page marker
-        Size = Y_LIKELY(size < Max<ui32>()) ? ui32(size) : Max<ui32>();
-    }
-
     TLabelWrapper::TResult TLabelWrapper::Read(TArrayRef<const char> raw, EPage type) const noexcept
     {
-        auto label = TDeref<TLabel>::Copy(raw.begin(), 0);
-
-        if (raw.size() < 8) {
-            Y_FAIL("NPage blob is too small to hold label");
-        } else if (label.Type != type && type != EPage::Undef) {
-            Y_FAIL("NPage blob has an unexpected label type");
-        } else if (label.Size != raw.size() && label.Size != Max<ui32>()) {
-            Y_FAIL("NPage label size doesn't match data size");
-        } else if (label.Size == Max<ui32>()) {
-            Y_VERIFY(raw.size() >= Max<ui32>(), "NPage label huge page marker doesn't match data size");
+        Y_VERIFY(raw.size() >= sizeof(TLabel), "Page blob is too small to hold label");
+
+        auto label = ReadUnaligned<TLabel>(raw.data());
+
+        Y_VERIFY(label.Type == type || type == EPage::Undef,
+            "Page blob has an unexpected label type");
+
+        if (Y_UNLIKELY(label.IsHuge())) {
+            Y_VERIFY(raw.size() >= Max<ui32>(), "Page label huge page marker doesn't match data size");
+        } else {
+            Y_VERIFY(label.Size == raw.size(), "Page label size doesn't match data size");
         }
 
         const ui16 version = label.Format & 0x7fff;
 
-        if (label.Format & 0x8000) {
-            /* New style NPage label, has at least extra 8 bytes, the
+        ECodec codec = ECodec::Plain;
+
+        auto* begin = raw.begin() + sizeof(TLabel);
+
+        if (label.IsExtended()) {
+            /* New style NPage label, has at least 8 extra bytes, the
                 current impl use only 1st byte. Futher is reserved for
                 in-place crc (may be) or other pages common metadata.
              */
 
-            // this ugly construct is just to get ui8 at raw.begin() + sizeof(TLabel)
-            auto codec = ECodec(*TDeref<ui8>::At(TDeref<TLabel>::At(raw.begin(), 0) + 1, 0));
-
-            auto *on = raw.begin() + sizeof(TLabel) + 8;
-
-            return { label.Type, version, codec, { on, raw.end() } };
+            Y_VERIFY(raw.size() >= sizeof(TLabel) + sizeof(TLabelExt), "Page extended label doesn't match data size");
 
-        } else {
-            /* old style NPage label, has no any extra attached data */
-
-            auto *on = raw.begin() + sizeof(TLabel);
-
-            return
-                { label.Type, version, ECodec::Plain, { on, raw.end() } };
+            auto ext = ReadUnaligned<TLabelExt>(begin);
+            codec = ext.Codec;
+            begin += sizeof(TLabelExt);
         }
+
+        return { label.Type, version, codec, { begin, raw.end() } };
     }
 
     TSharedData TLabelWrapper::Wrap(TArrayRef<const char> plain, EPage page, ui16 version) noexcept
@@ -63,7 +51,7 @@ namespace NPage {
 
         TSharedData blob = TSharedData::Uninitialized(plain.size() + 8);
 
-        TDeref<TLabel>::At(blob.mutable_begin(), 0)->Init(page, version, blob.size());
+        WriteUnaligned<TLabel>(blob.mutable_begin(), TLabel::Encode(page, version, blob.size()));
 
         std::copy(plain.begin(), plain.end(), blob.mutable_begin() + 8);
 
@@ -78,7 +66,7 @@ namespace NPage {
 
         TString blob = TString::Uninitialized(plain.size() + 8);
 
-        TDeref<TLabel>::At(blob.begin(), 0)->Init(page, version, blob.size());
+        WriteUnaligned<TLabel>(blob.begin(), TLabel::Encode(page, version, blob.size()));
 
         std::copy(plain.begin(), plain.end(), blob.begin() + 8);
 
diff --git a/ydb/core/tablet_flat/flat_page_label.h b/ydb/core/tablet_flat/flat_page_label.h
index 4a04c1f7c3e..36453fecd18 100644
--- a/ydb/core/tablet_flat/flat_page_label.h
+++ b/ydb/core/tablet_flat/flat_page_label.h
@@ -23,12 +23,48 @@ namespace NPage {
         ui16 Format; // most significant bit is format indicator, the rest is version
         TSize Size;
 
-        void Init(EPage type, ui16 format, ui64 size) noexcept;
-        void SetSize(ui64 size) noexcept;
+        bool IsExtended() const noexcept {
+            return Format & 0x8000;
+        }
+
+        bool IsHuge() const noexcept {
+            return Size == Max<ui32>();
+        }
+
+        static TLabel Encode(EPage type, ui16 format, ui64 size) noexcept {
+            TSize lsize;
+
+            if (Y_UNLIKELY(size >> 32)) {
+                // This size is used as a huge page marker
+                lsize = Max<ui32>();
+            } else {
+                lsize = TSize(size);
+            }
+
+            return TLabel{
+                .Type = type,
+                .Format = format,
+                .Size = lsize,
+            };
+        }
     };
 
     static_assert(sizeof(TLabel) == 8, "Invalid page TLabel unit");
 
+    struct TLabelExt {
+        ECodec Codec;
+        char Reserved[7];
+
+        static TLabelExt Encode(ECodec codec) noexcept {
+            return TLabelExt{
+                .Codec = codec,
+                .Reserved = {},
+            };
+        }
+    };
+
+    static_assert(sizeof(TLabelExt) == 8, "Invalid page TLabelExt size");
+
     struct TLabelWrapper {
         struct TResult {
             bool operator==(NPage::ECodec codec) const noexcept
diff --git a/ydb/core/tablet_flat/flat_page_other.h b/ydb/core/tablet_flat/flat_page_other.h
index 51e5e9f6589..147097957f4 100644
--- a/ydb/core/tablet_flat/flat_page_other.h
+++ b/ydb/core/tablet_flat/flat_page_other.h
@@ -90,11 +90,7 @@ namespace NPage {
 
             NUtil::NBin::TPut out(buf.mutable_begin());
 
-            if (auto *hdr = out.Skip<NPage::TLabel>()) {
-                hdr->Type = EPage::Frames;
-                hdr->Format = 0;
-                hdr->Size = size;
-            }
+            WriteUnaligned<TLabel>(out.Skip<TLabel>(), TLabel::Encode(EPage::Frames, 0, size));
 
             if (auto *post = out.Skip<THeader>()) {
                 Zero(*post);
@@ -183,11 +179,7 @@ namespace NPage {
 
             NUtil::NBin::TPut out(buf.mutable_begin());
 
-            if (auto *hdr = out.Skip<NPage::TLabel>()) {
-                hdr->Type = EPage::Globs;
-                hdr->Format = 1;
-                hdr->Size = size < Max<ui32>() ? ui32(size) : Max<ui32>();
-            }
+            WriteUnaligned<TLabel>(out.Skip<TLabel>(), TLabel::Encode(EPage::Globs, 1, size));
 
             if (auto *post = out.Skip<THeader>()) {
                 Zero(*post);
diff --git a/ydb/core/tablet_flat/flat_page_txidstat.h b/ydb/core/tablet_flat/flat_page_txidstat.h
index e58cda5c48f..05a3d1c5570 100644
--- a/ydb/core/tablet_flat/flat_page_txidstat.h
+++ b/ydb/core/tablet_flat/flat_page_txidstat.h
@@ -114,9 +114,7 @@ namespace NPage {
 
             NUtil::NBin::TPut out(buf.mutable_begin());
 
-            if (auto* label = out.Skip<TLabel>()) {
-                label->Init(EPage::TxIdStats, 0, pageSize);
-            }
+            WriteUnaligned<TLabel>(out.Skip<TLabel>(), TLabel::Encode(EPage::TxIdStats, 0, pageSize));
 
             if (auto* header = out.Skip<THeader>()) {
                 header->ItemCount = txIdList.size();
diff --git a/ydb/core/tablet_flat/flat_page_txstatus.h b/ydb/core/tablet_flat/flat_page_txstatus.h
index b7c99392a4b..2e4e7274d06 100644
--- a/ydb/core/tablet_flat/flat_page_txstatus.h
+++ b/ydb/core/tablet_flat/flat_page_txstatus.h
@@ -155,9 +155,7 @@ namespace NPage {
 
             NUtil::NBin::TPut out(buf.mutable_begin());
 
-            if (auto* label = out.Skip<TLabel>()) {
-                label->Init(EPage::TxStatus, 0, pageSize);
-            }
+            WriteUnaligned<TLabel>(out.Skip<TLabel>(), TLabel::Encode(EPage::TxStatus, 0, pageSize));
 
             if (auto* header = out.Skip<THeader>()) {
                 header->CommittedCount = CommittedItems.size();
diff --git a/ydb/core/tablet_flat/flat_page_writer.h b/ydb/core/tablet_flat/flat_page_writer.h
index 3c8f02aad63..6e9fcea1f10 100644
--- a/ydb/core/tablet_flat/flat_page_writer.h
+++ b/ydb/core/tablet_flat/flat_page_writer.h
@@ -23,7 +23,7 @@ namespace NPage {
             , Version(version)
             , V2Label(label)
             , Extra(extra)
-            , Prefix(sizeof(TLabel) + (label ? 8 : 0) + sizeof(TRecordsHeader) + Extra)
+            , Prefix(sizeof(TLabel) + (label ? sizeof(TLabelExt) : 0) + sizeof(TRecordsHeader) + Extra)
         {
             Y_VERIFY((version & 0x8000) == 0, "Invalid version value");
         }
@@ -82,15 +82,14 @@ namespace NPage {
 
             char *ptr = Blob.mutable_begin();
 
-            if (auto *label = TDeref<NPage::TLabel>::At(ptr, 0)) {
-                label->Init(Type, Version, Blob.size());
-
-                if (V2Label) {
-                    label->Format |= 0x8000;
-                    *TDeref<ui8>::At(label + 1, 0) = 0; /* page as-is */
-                }
-
-                ptr += sizeof(NPage::TLabel) + (V2Label ? 8 : 0);
+            if (V2Label) {
+                WriteUnaligned<NPage::TLabel>(ptr, TLabel::Encode(Type, Version | 0x8000, Blob.size()));
+                ptr += sizeof(TLabel);
+                WriteUnaligned<NPage::TLabelExt>(ptr, TLabelExt::Encode(ECodec::Plain));
+                ptr += sizeof(TLabelExt);
+            } else {
+                WriteUnaligned<NPage::TLabel>(ptr, TLabel::Encode(Type, Version, Blob.size()));
+                ptr += sizeof(TLabel);
             }
 
             if (auto *hdr = TDeref<TRecordsHeader>::At(ptr, 0)) {
diff --git a/ydb/core/tablet_flat/flat_part_dump.cpp b/ydb/core/tablet_flat/flat_part_dump.cpp
index 44f7da969a4..3604dba6991 100644
--- a/ydb/core/tablet_flat/flat_part_dump.cpp
+++ b/ydb/core/tablet_flat/flat_part_dump.cpp
@@ -90,13 +90,13 @@ namespace {
     {
         Key.reserve(part.Scheme->Groups[0].KeyTypes.size());
 
-        auto *label = part.Index.Label();
+        auto label = part.Index.Label();
 
         const auto items = (part.Index->End() - part.Index->Begin());
 
         Out
-            << " + Index{" << (ui16)label->Type << " rev "
-            << label->Format << ", " << label->Size << "b}"
+            << " + Index{" << (ui16)label.Type << " rev "
+            << label.Format << ", " << label.Size << "b}"
             << " " << items << " rec" << Endl
             << " |  Page     Row    Bytes  (";
 
@@ -145,10 +145,11 @@ namespace {
         // TODO: need to join with other column groups
         auto data = NPage::TDataPage(Env->TryGetPage(&part, page));
 
-        if (auto *label = data.Label()) {
+        if (data) {
+            auto label = data.Label();
             Out
-                << " + Rows{" << page << "} Label{" << page << (ui16)label->Type
-                << " rev " << label->Format << ", " << label->Size << "b}"
+                << " + Rows{" << page << "} Label{" << page << (ui16)label.Type
+                << " rev " << label.Format << ", " << label.Size << "b}"
                 << ", [" << data.BaseRow() << ", +" << data->Records << ")row"
                 << Endl;
 
diff --git a/ydb/core/tablet_flat/flat_part_writer.h b/ydb/core/tablet_flat/flat_part_writer.h
index bc3bb0e27a4..6239466a2a6 100644
--- a/ydb/core/tablet_flat/flat_part_writer.h
+++ b/ydb/core/tablet_flat/flat_part_writer.h
@@ -829,14 +829,16 @@ namespace NTable {
             if (!force && out.size() + (page.size() >> 3) > page.size()) {
                 return { }; /* Compressed page is almost the same in size */
             } else {
-                std::copy(page.begin(), page.begin() + 16, out.mutable_begin());
+                auto label = ReadUnaligned<NPage::TLabel>(page.begin());
 
-                auto *label = TDeref<NPage::TLabel>::At(out.mutable_begin(), 0);
-                label->SetSize(out.size());
+                Y_VERIFY(label.IsExtended(), "Expected an extended label");
 
-                *TDeref<ui8>::At(label + 1, 0) = ui8(ECodec::LZ4);
+                auto ext = ReadUnaligned<NPage::TLabelExt>(page.begin() + 8);
 
-                Y_VERIFY(label->Format & 0x8000, "Unexpected label version");
+                ext.Codec = ECodec::LZ4;
+
+                WriteUnaligned<NPage::TLabel>(out.mutable_begin(), NPage::TLabel::Encode(label.Type, label.Format, out.size()));
+                WriteUnaligned<NPage::TLabelExt>(out.mutable_begin() + 8, ext);
 
                 NSan::CheckMemIsInitialized(out.data(), out.size());
 
diff --git a/ydb/core/tablet_flat/test/libs/table/test_store.h b/ydb/core/tablet_flat/test/libs/table/test_store.h
index 0ea1c7192bb..2847ecbbd5b 100644
--- a/ydb/core/tablet_flat/test/libs/table/test_store.h
+++ b/ydb/core/tablet_flat/test/libs/table/test_store.h
@@ -160,9 +160,9 @@ namespace NTest {
 
                 TSharedData to = TSharedData::Uninitialized(label.Size);
 
-                *TDeref<NPage::TLabel>::At(to.mutable_begin(), 0) = label;
+                WriteUnaligned<NPage::TLabel>(to.mutable_begin(), label);
 
-                auto *begin = TDeref<char>::At(to.mutable_begin(), sizeof(label));
+                auto *begin = to.mutable_begin() + sizeof(NPage::TLabel);
 
                 got = in.Load(begin,  to.mutable_end() - begin);
 
diff --git a/ydb/core/tablet_flat/ut/ut_comp_gen.cpp b/ydb/core/tablet_flat/ut/ut_comp_gen.cpp
index d9d5c194a0f..45febc18efe 100644
--- a/ydb/core/tablet_flat/ut/ut_comp_gen.cpp
+++ b/ydb/core/tablet_flat/ut/ut_comp_gen.cpp
@@ -40,7 +40,7 @@ Y_UNIT_TEST_SUITE(TGenCompaction) {
             TCompactionPolicy policy;
 
             // almost randome values except forceCountToCompact = 1 and forceSizeToCompact = 100 GB
-            TCompactionPolicy::TGenerationPolicy genPolicy(1, 1, 1, 10*1024*1024*1024, "whoknows", true);
+            TCompactionPolicy::TGenerationPolicy genPolicy(1, 1, 1, 10ULL*1024*1024*1024, "whoknows", true);
 
             for (size_t i = 0; i < 5; ++i) {
                 policy.Generations.push_back(genPolicy);