8075816: Deprecate AliasLevel flag since it is broken

Reviewed-by: thartmann, kvn

Author: Tobias Holenstein

src/hotspot/share/opto/c2_globals.hpp

@@ -630,7 +630,8 @@
           range(1, max_intx)                                                \
                                                                             \
   product(intx, AliasLevel,     3,                                          \
-          "0 for no aliasing, 1 for oop/field/static/array split, "         \
+          "(Deprecated) 0 for no aliasing, "                                \
+          "1 for oop/field/static/array split, "                            \
           "2 for class split, 3 for unique instances")                      \
           range(0, 3)                                                       \
           constraint(AliasLevelConstraintFunc,AfterErgo)                    \

src/hotspot/share/runtime/arguments.cpp

@@ -542,6 +542,7 @@ static SpecialFlag const special_jvm_flags[] = {
   { "ExtendedDTraceProbes",         JDK_Version::jdk(19), JDK_Version::jdk(20), JDK_Version::jdk(21) },
   { "UseContainerCpuShares",        JDK_Version::jdk(19), JDK_Version::jdk(20), JDK_Version::jdk(21) },
   { "PreferContainerQuotaForCPUCount", JDK_Version::jdk(19), JDK_Version::jdk(20), JDK_Version::jdk(21) },
+  { "AliasLevel",                   JDK_Version::jdk(19), JDK_Version::jdk(20), JDK_Version::jdk(21) },
 
   // --- Deprecated alias flags (see also aliased_jvm_flags) - sorted by obsolete_in then expired_in:
   { "DefaultMaxRAMFraction",        JDK_Version::jdk(8),  JDK_Version::undefined(), JDK_Version::undefined() },

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

@@ -56,6 +56,7 @@ public class VMDeprecatedOptions {
             {"InitialRAMFraction",        "64"},
             {"TLABStats",                 "false"},
             {"AllowRedefinitionToAddDeleteMethods", "true"},
+            {"AliasLevel", "3"},
 
             // deprecated alias flags (see also aliased_jvm_flags):
             {"DefaultMaxRAMFraction", "4"},