8330607: Deprecate -XX:+UseEmptySlotsInSupers

Reviewed-by: shade, dcubed

Author: coleenp

src/hotspot/share/runtime/arguments.cpp

@@ -502,6 +502,7 @@ static SpecialFlag const special_jvm_flags[] = {
   { "UseSharedSpaces",              JDK_Version::jdk(18), JDK_Version::jdk(19), JDK_Version::undefined() },
   { "RegisterFinalizersAtInit",     JDK_Version::jdk(22), JDK_Version::jdk(23), JDK_Version::jdk(24) },
   { "PreserveAllAnnotations",       JDK_Version::jdk(23), JDK_Version::jdk(24), JDK_Version::jdk(25) },
+  { "UseEmptySlotsInSupers",        JDK_Version::jdk(23), JDK_Version::jdk(24), JDK_Version::jdk(25) },
 #if defined(X86)
   { "UseRTMLocking",                JDK_Version::jdk(23), JDK_Version::jdk(24), JDK_Version::jdk(25) },
   { "UseRTMDeopt",                  JDK_Version::jdk(23), JDK_Version::jdk(24), JDK_Version::jdk(25) },

src/hotspot/share/runtime/globals.hpp

@@ -1958,7 +1958,8 @@ const int ObjectAlignmentInBytes = 8;
           "Use platform unstable time where supported for timestamps only") \
                                                                             \
   product(bool, UseEmptySlotsInSupers, true,                                \
-                "Allow allocating fields in empty slots of super-classes")  \
+          "(Deprecated) Allow allocating fields in empty slots of "         \
+          "super-classes")                                                  \
                                                                             \
   product(bool, DeoptimizeNMethodBarriersALot, false, DIAGNOSTIC,           \
                 "Make nmethod barriers deoptimise a lot.")                  \

test/hotspot/jtreg/runtime/CommandLine/VMDeprecatedOptions.java

@@ -58,6 +58,7 @@ public class VMDeprecatedOptions {
             // deprecated non-alias flags:
             {"PreserveAllAnnotations", "true"},
             {"AllowRedefinitionToAddDeleteMethods", "true"},
+            {"UseEmptySlotsInSupers", "true"},
 
             // deprecated alias flags (see also aliased_jvm_flags):
             {"CreateMinidumpOnCrash", "false"}