diff --git a/MdePkg/Include/Library/PerformanceLib.h b/MdePkg/Include/Library/PerformanceLib.h
index 34ec956b9c..d0f2dfb070 100644
--- a/MdePkg/Include/Library/PerformanceLib.h
+++ b/MdePkg/Include/Library/PerformanceLib.h
@@ -526,7 +526,7 @@ LogPerformanceMeasurement (
 #define PERF_EVENT_SIGNAL_BEGIN(EventGuid) \
   do { \
     if (LogPerformanceMeasurementEnabled (PERF_GENERAL_TYPE)) { \
-      LogPerformanceMeasurement (&gEfiCallerIdGuid, EventGuid, __FUNCTION__ , 0, PERF_EVENTSIGNAL_START_ID); \
+      LogPerformanceMeasurement (&gEfiCallerIdGuid, EventGuid, __func__ , 0, PERF_EVENTSIGNAL_START_ID); \
     } \
   } while (FALSE)
 
@@ -542,7 +542,7 @@ LogPerformanceMeasurement (
 #define PERF_EVENT_SIGNAL_END(EventGuid) \
   do { \
     if (LogPerformanceMeasurementEnabled (PERF_GENERAL_TYPE)) { \
-      LogPerformanceMeasurement (&gEfiCallerIdGuid, EventGuid, __FUNCTION__ , 0, PERF_EVENTSIGNAL_END_ID); \
+      LogPerformanceMeasurement (&gEfiCallerIdGuid, EventGuid, __func__ , 0, PERF_EVENTSIGNAL_END_ID); \
     } \
   } while (FALSE)
 
@@ -558,7 +558,7 @@ LogPerformanceMeasurement (
 #define PERF_CALLBACK_BEGIN(TriggerGuid) \
   do { \
     if (LogPerformanceMeasurementEnabled (PERF_GENERAL_TYPE)) { \
-      LogPerformanceMeasurement (&gEfiCallerIdGuid, TriggerGuid, __FUNCTION__ , 0, PERF_CALLBACK_START_ID); \
+      LogPerformanceMeasurement (&gEfiCallerIdGuid, TriggerGuid, __func__ , 0, PERF_CALLBACK_START_ID); \
     } \
   } while (FALSE)
 
@@ -574,7 +574,7 @@ LogPerformanceMeasurement (
 #define PERF_CALLBACK_END(TriggerGuid) \
   do { \
     if (LogPerformanceMeasurementEnabled (PERF_GENERAL_TYPE)) { \
-      LogPerformanceMeasurement (&gEfiCallerIdGuid, TriggerGuid, __FUNCTION__ , 0, PERF_CALLBACK_END_ID); \
+      LogPerformanceMeasurement (&gEfiCallerIdGuid, TriggerGuid, __func__ , 0, PERF_CALLBACK_END_ID); \
     } \
   } while (FALSE)
 
@@ -589,7 +589,7 @@ LogPerformanceMeasurement (
 #define PERF_FUNCTION_BEGIN() \
   do { \
     if (LogPerformanceMeasurementEnabled (PERF_GENERAL_TYPE)) { \
-      LogPerformanceMeasurement (&gEfiCallerIdGuid, NULL, __FUNCTION__ , 0, PERF_FUNCTION_START_ID); \
+      LogPerformanceMeasurement (&gEfiCallerIdGuid, NULL, __func__ , 0, PERF_FUNCTION_START_ID); \
     } \
   } while (FALSE)
 
@@ -604,7 +604,7 @@ LogPerformanceMeasurement (
 #define PERF_FUNCTION_END() \
   do { \
     if (LogPerformanceMeasurementEnabled (PERF_GENERAL_TYPE)) { \
-      LogPerformanceMeasurement (&gEfiCallerIdGuid, NULL, __FUNCTION__ , 0, PERF_FUNCTION_END_ID); \
+      LogPerformanceMeasurement (&gEfiCallerIdGuid, NULL, __func__ , 0, PERF_FUNCTION_END_ID); \
     } \
   } while (FALSE)
 
diff --git a/MdePkg/Include/Library/UnitTestLib.h b/MdePkg/Include/Library/UnitTestLib.h
index 71c205b1b1..321a310602 100644
--- a/MdePkg/Include/Library/UnitTestLib.h
+++ b/MdePkg/Include/Library/UnitTestLib.h
@@ -348,7 +348,7 @@ SaveFrameworkState (
   @param[in]  Expression  Expression to be evaluated for TRUE.
 **/
 #define UT_ASSERT_TRUE(Expression)                                                                 \
-  if(!UnitTestAssertTrue ((Expression), __FUNCTION__, DEBUG_LINE_NUMBER, __FILE__, #Expression)) { \
+  if(!UnitTestAssertTrue ((Expression), __func__, DEBUG_LINE_NUMBER, __FILE__, #Expression)) { \
     return UNIT_TEST_ERROR_TEST_FAILED;                                                            \
   }
 
@@ -360,7 +360,7 @@ SaveFrameworkState (
   @param[in]  Expression  Expression to be evaluated for FALSE.
 **/
 #define UT_ASSERT_FALSE(Expression)                                                                 \
-  if(!UnitTestAssertFalse ((Expression), __FUNCTION__, DEBUG_LINE_NUMBER, __FILE__, #Expression)) { \
+  if(!UnitTestAssertFalse ((Expression), __func__, DEBUG_LINE_NUMBER, __FILE__, #Expression)) { \
     return UNIT_TEST_ERROR_TEST_FAILED;                                                             \
   }
 
@@ -373,7 +373,7 @@ SaveFrameworkState (
   @param[in]  ValueB  Value to be compared for equality (64-bit comparison).
 **/
 #define UT_ASSERT_EQUAL(ValueA, ValueB)                                                                           \
-  if(!UnitTestAssertEqual ((UINT64)(ValueA), (UINT64)(ValueB), __FUNCTION__, DEBUG_LINE_NUMBER, __FILE__, #ValueA, #ValueB)) { \
+  if(!UnitTestAssertEqual ((UINT64)(ValueA), (UINT64)(ValueB), __func__, DEBUG_LINE_NUMBER, __FILE__, #ValueA, #ValueB)) { \
     return UNIT_TEST_ERROR_TEST_FAILED;                                                                           \
   }
 
@@ -387,7 +387,7 @@ SaveFrameworkState (
   @param[in]  Length   Number of bytes to compare in BufferA and BufferB.
 **/
 #define UT_ASSERT_MEM_EQUAL(BufferA, BufferB, Length)                                                                                                              \
-  if(!UnitTestAssertMemEqual ((VOID *)(UINTN)(BufferA), (VOID *)(UINTN)(BufferB), (UINTN)Length, __FUNCTION__, DEBUG_LINE_NUMBER, __FILE__, #BufferA, #BufferB)) { \
+  if(!UnitTestAssertMemEqual ((VOID *)(UINTN)(BufferA), (VOID *)(UINTN)(BufferB), (UINTN)Length, __func__, DEBUG_LINE_NUMBER, __FILE__, #BufferA, #BufferB)) { \
     return UNIT_TEST_ERROR_TEST_FAILED;                                                                                                                            \
   }
 
@@ -400,7 +400,7 @@ SaveFrameworkState (
   @param[in]  ValueB  Value to be compared for inequality (64-bit comparison).
 **/
 #define UT_ASSERT_NOT_EQUAL(ValueA, ValueB)                                                                                       \
-  if(!UnitTestAssertNotEqual ((UINT64)(ValueA), (UINT64)(ValueB), __FUNCTION__, DEBUG_LINE_NUMBER, __FILE__, #ValueA, #ValueB)) { \
+  if(!UnitTestAssertNotEqual ((UINT64)(ValueA), (UINT64)(ValueB), __func__, DEBUG_LINE_NUMBER, __FILE__, #ValueA, #ValueB)) { \
     return UNIT_TEST_ERROR_TEST_FAILED;                                                                                           \
   }
 
@@ -412,7 +412,7 @@ SaveFrameworkState (
   @param[in]  Status  EFI_STATUS value to check.
 **/
 #define UT_ASSERT_NOT_EFI_ERROR(Status)                                                           \
-  if(!UnitTestAssertNotEfiError ((Status), __FUNCTION__, DEBUG_LINE_NUMBER, __FILE__, #Status)) { \
+  if(!UnitTestAssertNotEfiError ((Status), __func__, DEBUG_LINE_NUMBER, __FILE__, #Status)) { \
     return UNIT_TEST_ERROR_TEST_FAILED;                                                           \
   }
 
@@ -425,7 +425,7 @@ SaveFrameworkState (
   @param[in]  Expected  EFI_STATUS values to compare for equality.
 **/
 #define UT_ASSERT_STATUS_EQUAL(Status, Expected)                                                              \
-  if(!UnitTestAssertStatusEqual ((Status), (Expected), __FUNCTION__, DEBUG_LINE_NUMBER, __FILE__, #Status)) { \
+  if(!UnitTestAssertStatusEqual ((Status), (Expected), __func__, DEBUG_LINE_NUMBER, __FILE__, #Status)) { \
     return UNIT_TEST_ERROR_TEST_FAILED;                                                                       \
   }
 
@@ -437,7 +437,7 @@ SaveFrameworkState (
   @param[in]  Pointer  Pointer to be checked against NULL.
 **/
 #define UT_ASSERT_NOT_NULL(Pointer)                                                             \
-  if(!UnitTestAssertNotNull ((Pointer), __FUNCTION__, DEBUG_LINE_NUMBER, __FILE__, #Pointer)) { \
+  if(!UnitTestAssertNotNull ((Pointer), __func__, DEBUG_LINE_NUMBER, __FILE__, #Pointer)) { \
     return UNIT_TEST_ERROR_TEST_FAILED;                                                         \
   }
 
@@ -482,7 +482,7 @@ extern BASE_LIBRARY_JUMP_BUFFER  *gUnitTestExpectAssertFailureJumpBuffer;
       }                                                                \
       if (!UnitTestExpectAssertFailure (                               \
              UnitTestJumpStatus,                                       \
-             __FUNCTION__, DEBUG_LINE_NUMBER, __FILE__,                \
+             __func__, DEBUG_LINE_NUMBER, __FILE__,                \
              #FunctionCall, Status)) {                                 \
         return UNIT_TEST_ERROR_TEST_FAILED;                            \
       }                                                                \
diff --git a/MdePkg/Library/BaseCacheMaintenanceLib/LoongArchCache.c b/MdePkg/Library/BaseCacheMaintenanceLib/LoongArchCache.c
index 4c8773278c..617b0f4218 100644
--- a/MdePkg/Library/BaseCacheMaintenanceLib/LoongArchCache.c
+++ b/MdePkg/Library/BaseCacheMaintenanceLib/LoongArchCache.c
@@ -100,7 +100,7 @@ WriteBackInvalidateDataCache (
   VOID
   )
 {
-  DEBUG ((DEBUG_ERROR, "%a: Not currently implemented on LoongArch.\n", __FUNCTION__));
+  DEBUG ((DEBUG_ERROR, "%a: Not currently implemented on LoongArch.\n", __func__));
 }
 
 /**
@@ -136,7 +136,7 @@ WriteBackInvalidateDataCacheRange (
   IN      UINTN  Length
   )
 {
-  DEBUG ((DEBUG_ERROR, "%a: Not currently implemented on LoongArch.\n", __FUNCTION__));
+  DEBUG ((DEBUG_ERROR, "%a: Not currently implemented on LoongArch.\n", __func__));
   return Address;
 }
 
@@ -191,7 +191,7 @@ WriteBackDataCacheRange (
   IN      UINTN  Length
   )
 {
-  DEBUG ((DEBUG_ERROR, "%a: Not currently implemented on LoongArch.\n", __FUNCTION__));
+  DEBUG ((DEBUG_ERROR, "%a: Not currently implemented on LoongArch.\n", __func__));
   return Address;
 }
 
diff --git a/MdePkg/Library/BaseCacheMaintenanceLib/RiscVCache.c b/MdePkg/Library/BaseCacheMaintenanceLib/RiscVCache.c
index 9a6d57d841..d08fb9f193 100644
--- a/MdePkg/Library/BaseCacheMaintenanceLib/RiscVCache.c
+++ b/MdePkg/Library/BaseCacheMaintenanceLib/RiscVCache.c
@@ -101,7 +101,7 @@ WriteBackInvalidateDataCache (
   VOID
   )
 {
-  DEBUG ((DEBUG_ERROR, "%a:RISC-V unsupported function.\n", __FUNCTION__));
+  DEBUG ((DEBUG_ERROR, "%a:RISC-V unsupported function.\n", __func__));
 }
 
 /**
@@ -137,7 +137,7 @@ WriteBackInvalidateDataCacheRange (
   IN      UINTN  Length
   )
 {
-  DEBUG ((DEBUG_ERROR, "%a:RISC-V unsupported function.\n", __FUNCTION__));
+  DEBUG ((DEBUG_ERROR, "%a:RISC-V unsupported function.\n", __func__));
   return Address;
 }
 
@@ -157,7 +157,7 @@ WriteBackDataCache (
   VOID
   )
 {
-  DEBUG ((DEBUG_ERROR, "%a:RISC-V unsupported function.\n", __FUNCTION__));
+  DEBUG ((DEBUG_ERROR, "%a:RISC-V unsupported function.\n", __func__));
 }
 
 /**
@@ -192,7 +192,7 @@ WriteBackDataCacheRange (
   IN      UINTN  Length
   )
 {
-  DEBUG ((DEBUG_ERROR, "%a:RISC-V unsupported function.\n", __FUNCTION__));
+  DEBUG ((DEBUG_ERROR, "%a:RISC-V unsupported function.\n", __func__));
   return Address;
 }
 
@@ -250,6 +250,6 @@ InvalidateDataCacheRange (
   IN      UINTN  Length
   )
 {
-  DEBUG ((DEBUG_ERROR, "%a:RISC-V unsupported function.\n", __FUNCTION__));
+  DEBUG ((DEBUG_ERROR, "%a:RISC-V unsupported function.\n", __func__));
   return Address;
 }
diff --git a/MdePkg/Library/BaseLib/SafeString.c b/MdePkg/Library/BaseLib/SafeString.c
index b75b333817..954d3f8c89 100644
--- a/MdePkg/Library/BaseLib/SafeString.c
+++ b/MdePkg/Library/BaseLib/SafeString.c
@@ -17,7 +17,7 @@
     if (!(Expression)) { \
       DEBUG ((DEBUG_VERBOSE, \
         "%a(%d) %a: SAFE_STRING_CONSTRAINT_CHECK(%a) failed.  Return %r\n", \
-        __FILE__, DEBUG_LINE_NUMBER, __FUNCTION__, DEBUG_EXPRESSION_STRING (Expression), Status)); \
+        __FILE__, DEBUG_LINE_NUMBER, __func__, DEBUG_EXPRESSION_STRING (Expression), Status)); \
       return Status; \
     } \
   } while (FALSE)
diff --git a/MdePkg/Library/BaseOrderedCollectionRedBlackTreeLib/BaseOrderedCollectionRedBlackTreeLib.c b/MdePkg/Library/BaseOrderedCollectionRedBlackTreeLib/BaseOrderedCollectionRedBlackTreeLib.c
index f47301de89..a23113f9c9 100644
--- a/MdePkg/Library/BaseOrderedCollectionRedBlackTreeLib/BaseOrderedCollectionRedBlackTreeLib.c
+++ b/MdePkg/Library/BaseOrderedCollectionRedBlackTreeLib/BaseOrderedCollectionRedBlackTreeLib.c
@@ -1416,7 +1416,7 @@ RedBlackTreeValidate (
   CONST RED_BLACK_TREE_NODE  *Last;
   CONST RED_BLACK_TREE_NODE  *Node;
 
-  DEBUG ((DEBUG_VERBOSE, "%a: Tree=%p\n", __FUNCTION__, Tree));
+  DEBUG ((DEBUG_VERBOSE, "%a: Tree=%p\n", __func__, Tree));
 
   //
   // property #5
@@ -1459,7 +1459,7 @@ RedBlackTreeValidate (
   DEBUG ((
     DEBUG_VERBOSE,
     "%a: Tree=%p BlackHeight=%Ld Count=%Ld\n",
-    __FUNCTION__,
+    __func__,
     Tree,
     (INT64)BlackHeight,
     (INT64)ForwardCount
diff --git a/MdePkg/Library/DxeRngLib/DxeRngLib.c b/MdePkg/Library/DxeRngLib/DxeRngLib.c
index 82129aa445..46aea51592 100644
--- a/MdePkg/Library/DxeRngLib/DxeRngLib.c
+++ b/MdePkg/Library/DxeRngLib/DxeRngLib.c
@@ -37,43 +37,43 @@ GenerateRandomNumberViaNist800Algorithm (
   RngProtocol = NULL;
 
   if (Buffer == NULL) {
-    DEBUG ((DEBUG_ERROR, "%a: Buffer == NULL.\n", __FUNCTION__));
+    DEBUG ((DEBUG_ERROR, "%a: Buffer == NULL.\n", __func__));
     return EFI_INVALID_PARAMETER;
   }
 
   Status = gBS->LocateProtocol (&gEfiRngProtocolGuid, NULL, (VOID **)&RngProtocol);
   if (EFI_ERROR (Status) || (RngProtocol == NULL)) {
-    DEBUG ((DEBUG_ERROR, "%a: Could not locate RNG prototocol, Status = %r\n", __FUNCTION__, Status));
+    DEBUG ((DEBUG_ERROR, "%a: Could not locate RNG prototocol, Status = %r\n", __func__, Status));
     return Status;
   }
 
   Status = RngProtocol->GetRNG (RngProtocol, &gEfiRngAlgorithmSp80090Ctr256Guid, BufferSize, Buffer);
-  DEBUG ((DEBUG_INFO, "%a: GetRNG algorithm CTR-256 - Status = %r\n", __FUNCTION__, Status));
+  DEBUG ((DEBUG_INFO, "%a: GetRNG algorithm CTR-256 - Status = %r\n", __func__, Status));
   if (!EFI_ERROR (Status)) {
     return Status;
   }
 
   Status = RngProtocol->GetRNG (RngProtocol, &gEfiRngAlgorithmSp80090Hmac256Guid, BufferSize, Buffer);
-  DEBUG ((DEBUG_INFO, "%a: GetRNG algorithm HMAC-256 - Status = %r\n", __FUNCTION__, Status));
+  DEBUG ((DEBUG_INFO, "%a: GetRNG algorithm HMAC-256 - Status = %r\n", __func__, Status));
   if (!EFI_ERROR (Status)) {
     return Status;
   }
 
   Status = RngProtocol->GetRNG (RngProtocol, &gEfiRngAlgorithmSp80090Hash256Guid, BufferSize, Buffer);
-  DEBUG ((DEBUG_INFO, "%a: GetRNG algorithm Hash-256 - Status = %r\n", __FUNCTION__, Status));
+  DEBUG ((DEBUG_INFO, "%a: GetRNG algorithm Hash-256 - Status = %r\n", __func__, Status));
   if (!EFI_ERROR (Status)) {
     return Status;
   }
 
   // If all the other methods have failed, use the default method from the RngProtocol
   Status = RngProtocol->GetRNG (RngProtocol, NULL, BufferSize, Buffer);
-  DEBUG ((DEBUG_INFO, "%a: GetRNG algorithm Hash-256 - Status = %r\n", __FUNCTION__, Status));
+  DEBUG ((DEBUG_INFO, "%a: GetRNG algorithm Hash-256 - Status = %r\n", __func__, Status));
   if (!EFI_ERROR (Status)) {
     return Status;
   }
 
   // If we get to this point, we have failed
-  DEBUG ((DEBUG_ERROR, "%a: GetRNG() failed, staus = %r\n", __FUNCTION__, Status));
+  DEBUG ((DEBUG_ERROR, "%a: GetRNG() failed, staus = %r\n", __func__, Status));
 
   return Status;
 }// GenerateRandomNumberViaNist800Algorithm()