SERVER-105931 Remove bsoncolumn_helpers.h from ubsan deny (#37450)

GitOrigin-RevId: 1073f04a1a7c605cff233fe79de7291eded900e7

etc/ubsan.denylist

@@ -15,7 +15,6 @@ src:src/third_party/immer/dist/immer/detail/hamts/node.hpp
 # s2 compatibility
 fun:_ZN8S2CellId14FromFaceIJWrapEiii
 
-src:src/mongo/bson/column/bsoncolumn_helpers.h
 src:src/third_party/abseil-cpp/dist/absl/numeric/int128_have_intrinsic.inc
 
 # SERVER-62972

src/mongo/bson/column/bsoncolumn_helpers.h

@@ -44,6 +44,7 @@
 #include <boost/container/small_vector.hpp>
 
 namespace mongo {
+
 namespace bsoncolumn {
 
 /**
@@ -551,7 +552,7 @@ public:
                     bsoncolumn::scaleIndexForControlByte(control) ==
                         Simple8bTypeUtil::kMemoryAsInteger);
 
-            out += simple8b::sum<Encoding>(ptr + 1, size, lastNonRLEBlock);
+            out = simple8b::add(out, simple8b::sum<Encoding>(ptr + 1, size, lastNonRLEBlock));
 
             ptr += 1 + size;
         }
@@ -576,7 +577,8 @@ public:
                     bsoncolumn::scaleIndexForControlByte(control) ==
                         Simple8bTypeUtil::kMemoryAsInteger);
 
-            out += simple8b::prefixSum<Encoding>(ptr + 1, size, prefix, lastNonRLEBlock);
+            out = simple8b::add(
+                out, simple8b::prefixSum<Encoding>(ptr + 1, size, prefix, lastNonRLEBlock));
 
             ptr += 1 + size;
         }
@@ -603,7 +605,8 @@ public:
             auto encodedDouble = Simple8bTypeUtil::encodeDouble(last, scaleIndex);
             uassert(9095626, "Invalid double encoding in BSON Column", encodedDouble);
             lastValue = *encodedDouble;
-            lastValue += simple8b::sum<int64_t>(ptr + 1, size, lastNonRLEBlock);
+            lastValue =
+                simple8b::add(lastValue, simple8b::sum<int64_t>(ptr + 1, size, lastNonRLEBlock));
 
             last = Simple8bTypeUtil::decodeDouble(lastValue, scaleIndex);
 
@@ -636,7 +639,7 @@ public:
                         bsoncolumn::scaleIndexForControlByte(control) ==
                             Simple8bTypeUtil::kMemoryAsInteger);
 
-                out += simple8b::sum<int128_t>(ptr + 1, size, lastNonRLEBlock);
+                out = simple8b::add(out, simple8b::sum<int128_t>(ptr + 1, size, lastNonRLEBlock));
 
                 ptr += 1 + size;
             }

src/mongo/bson/column/simple8b.h

@@ -399,6 +399,18 @@ T sum(const char* buffer, size_t size, uint64_t& prevNonRLE);
  */
 template <typename T>
 T prefixSum(const char* buffer, size_t size, T& prefix, uint64_t& prevNonRLE);
+
+/**
+ * Helper that performs signed addition as unsigned to get the defined wrap-around overflow behavior
+ * rather than overflow, which is undefined behavior.
+ */
+static constexpr int64_t add(int64_t lhs, int64_t rhs) {
+    return static_cast<int64_t>(static_cast<uint64_t>(lhs) + static_cast<uint64_t>(rhs));
+}
+static constexpr int128_t add(int128_t lhs, int128_t rhs) {
+    return static_cast<int128_t>(static_cast<uint128_t>(lhs) + static_cast<uint128_t>(rhs));
+}
+
 }  // namespace simple8b
 
 }  // namespace mongo

src/mongo/bson/column/simple8b.inl

@@ -37,16 +37,6 @@ namespace {
 // Sentinel to represent missing, this value is not encodable in simple8b
 static constexpr int64_t kMissing = std::numeric_limits<int64_t>::max();
 
-// Performs addition as unsigned and cast back to signed to get overflow defined to wrapped around
-// instead of undefined behavior.
-static constexpr int64_t add(int64_t lhs, int64_t rhs) {
-    return static_cast<int64_t>(static_cast<uint64_t>(lhs) + static_cast<uint64_t>(rhs));
-}
-
-static constexpr int128_t add(int128_t lhs, int128_t rhs) {
-    return static_cast<int128_t>(static_cast<uint128_t>(lhs) + static_cast<uint128_t>(rhs));
-}
-
 // Simple Simple8b decoder for decoding any basic simple8b block where all bits are used for the
 // value, decodes signed integer at runtime. Suitable for selectors with many bits per slot. Encoded
 // should be be machine endian and first slot should start at least significant bit.