SERVER-59446 Use memcpy instead of reinterpret_cast for doing bit casting between types

2 files changed, 14 insertions, 5 deletions

diff --git a/src/mongo/bson/util/simple8b_type_util.cpp b/src/mongo/bson/util/simple8b_type_util.cpp
index 8858552e8ae..61787104f9b 100644
--- a/src/mongo/bson/util/simple8b_type_util.cpp
+++ b/src/mongo/bson/util/simple8b_type_util.cpp
@@ -133,8 +133,11 @@ boost::optional<uint8_t> Simple8bTypeUtil::calculateDecimalShiftMultiplier(doubl
 }
 
 boost::optional<int64_t> Simple8bTypeUtil::encodeDouble(double val, uint8_t scaleIndex) {
-    if (scaleIndex == kMemoryAsInteger)
-        return *reinterpret_cast<int64_t*>(&val);
+    if (scaleIndex == kMemoryAsInteger) {
+        int64_t ret;
+        memcpy(&ret, &val, sizeof(ret));
+        return ret;
+    }
 
     // Checks for both overflow and handles NaNs
     // We use 2^53 because this is the max integer that we can guarentee can be
@@ -160,8 +163,11 @@ boost::optional<int64_t> Simple8bTypeUtil::encodeDouble(double val, uint8_t scal
 }
 
 double Simple8bTypeUtil::decodeDouble(int64_t val, uint8_t scaleIndex) {
-    if (scaleIndex == kMemoryAsInteger)
-        return *reinterpret_cast<double*>(&val);
+    if (scaleIndex == kMemoryAsInteger) {
+        double ret;
+        memcpy(&ret, &val, sizeof(ret));
+        return ret;
+    }
 
     return val / kScaleMultiplier[scaleIndex];
 }
diff --git a/src/mongo/bson/util/simple8b_type_util_test.cpp b/src/mongo/bson/util/simple8b_type_util_test.cpp
index 6275839b4f4..5d4e3051dce 100644
--- a/src/mongo/bson/util/simple8b_type_util_test.cpp
+++ b/src/mongo/bson/util/simple8b_type_util_test.cpp
@@ -261,7 +261,10 @@ TEST(Simple8bTypeUtil, InterpretAsMemory) {
         boost::optional<int64_t> result =
             Simple8bTypeUtil::encodeDouble(val, Simple8bTypeUtil::kMemoryAsInteger);
         ASSERT_TRUE(result);
-        ASSERT_EQ(*result, *reinterpret_cast<const int64_t*>(&val));
+
+        int64_t valInt;
+        memcpy(&valInt, &val, sizeof(valInt));
+        ASSERT_EQ(*result, valInt);
 
         // Some of the special values above does not compare equal with themselves (signaling NaN).
         // Verify that we end up with the same memory after decoding