1 /*
   2  * Copyright (c) 1997, 2021, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #ifndef SHARE_RUNTIME_GLOBALS_HPP
  26 #define SHARE_RUNTIME_GLOBALS_HPP
  27 
  28 #include "compiler/compiler_globals_pd.hpp"
  29 #include "runtime/globals_shared.hpp"
  30 #include "utilities/align.hpp"
  31 #include "utilities/globalDefinitions.hpp"
  32 #include "utilities/macros.hpp"
  33 #include CPU_HEADER(globals)
  34 #include OS_HEADER(globals)
  35 #include OS_CPU_HEADER(globals)
  36 
  37 // develop flags are settable / visible only during development and are constant in the PRODUCT version
  38 // product flags are always settable / visible
  39 // notproduct flags are settable / visible only during development and are not declared in the PRODUCT version
  40 // develop_pd/product_pd flags are the same as develop/product, except that their default values
  41 // are specified in platform-dependent header files.
  42 
  43 // Flags must be declared with the following number of parameters:
  44 // non-pd flags:
  45 //    (type, name, default_value, doc), or
  46 //    (type, name, default_value, extra_attrs, doc)
  47 // pd flags:
  48 //    (type, name, doc), or
  49 //    (type, name, extra_attrs, doc)
  50 
  51 // A flag must be declared with one of the following types:
  52 // bool, int, uint, intx, uintx, size_t, ccstr, ccstrlist, double, or uint64_t.
  53 // The type "ccstr" and "ccstrlist" are an alias for "const char*" and is used
  54 // only in this file, because the macrology requires single-token type names.
  55 
  56 // The optional extra_attrs parameter may have one of the following values:
  57 // DIAGNOSTIC, EXPERIMENTAL, or MANAGEABLE. Currently extra_attrs can be used
  58 // only with product/product_pd flags.
  59 //
  60 // DIAGNOSTIC options are not meant for VM tuning or for product modes.
  61 //    They are to be used for VM quality assurance or field diagnosis
  62 //    of VM bugs.  They are hidden so that users will not be encouraged to
  63 //    try them as if they were VM ordinary execution options.  However, they
  64 //    are available in the product version of the VM.  Under instruction
  65 //    from support engineers, VM customers can turn them on to collect
  66 //    diagnostic information about VM problems.  To use a VM diagnostic
  67 //    option, you must first specify +UnlockDiagnosticVMOptions.
  68 //    (This master switch also affects the behavior of -Xprintflags.)
  69 //
  70 // EXPERIMENTAL flags are in support of features that are not
  71 //    part of the officially supported product, but are available
  72 //    for experimenting with. They could, for example, be performance
  73 //    features that may not have undergone full or rigorous QA, but which may
  74 //    help performance in some cases and released for experimentation
  75 //    by the community of users and developers. This flag also allows one to
  76 //    be able to build a fully supported product that nonetheless also
  77 //    ships with some unsupported, lightly tested, experimental features.
  78 //    Like the UnlockDiagnosticVMOptions flag above, there is a corresponding
  79 //    UnlockExperimentalVMOptions flag, which allows the control and
  80 //    modification of the experimental flags.
  81 //
  82 // Nota bene: neither diagnostic nor experimental options should be used casually,
  83 //    and they are not supported on production loads, except under explicit
  84 //    direction from support engineers.
  85 //
  86 // MANAGEABLE flags are writeable external product flags.
  87 //    They are dynamically writeable through the JDK management interface
  88 //    (com.sun.management.HotSpotDiagnosticMXBean API) and also through JConsole.
  89 //    These flags are external exported interface (see CCC).  The list of
  90 //    manageable flags can be queried programmatically through the management
  91 //    interface.
  92 //
  93 //    A flag can be made as "manageable" only if
  94 //    - the flag is defined in a CCC as an external exported interface.
  95 //    - the VM implementation supports dynamic setting of the flag.
  96 //      This implies that the VM must *always* query the flag variable
  97 //      and not reuse state related to the flag state at any given time.
  98 //    - you want the flag to be queried programmatically by the customers.
  99 //
 100 
 101 //
 102 // range is a macro that will expand to min and max arguments for range
 103 //    checking code if provided - see jvmFlagLimit.hpp
 104 //
 105 // constraint is a macro that will expand to custom function call
 106 //    for constraint checking if provided - see jvmFlagLimit.hpp
 107 
 108 // Default and minimum StringTable and SymbolTable size values
 109 // Must be powers of 2
 110 const size_t defaultStringTableSize = NOT_LP64(1024) LP64_ONLY(65536);
 111 const size_t minimumStringTableSize = 128;
 112 const size_t defaultSymbolTableSize = 32768; // 2^15
 113 const size_t minimumSymbolTableSize = 1024;
 114 
 115 #ifdef _LP64
 116 #define LP64_RUNTIME_FLAGS(develop,                                         \
 117                            develop_pd,                                      \
 118                            product,                                         \
 119                            product_pd,                                      \
 120                            notproduct,                                      \
 121                            range,                                           \
 122                            constraint)                                      \
 123                                                                             \
 124   product(bool, UseCompressedOops, false,                                   \
 125           "Use 32-bit object references in 64-bit VM. "                     \
 126           "lp64_product means flag is always constant in 32 bit VM")        \
 127                                                                             \
 128   product(bool, UseCompressedClassPointers, false,                          \
 129           "Use 32-bit class pointers in 64-bit VM. "                        \
 130           "lp64_product means flag is always constant in 32 bit VM")        \
 131                                                                             \
 132   product(intx, ObjectAlignmentInBytes, 8,                                  \
 133           "Default object alignment in bytes, 8 is minimum")                \
 134           range(8, 256)                                                     \
 135           constraint(ObjectAlignmentInBytesConstraintFunc, AtParse)
 136 
 137 #else
 138 // !_LP64
 139 
 140 #define LP64_RUNTIME_FLAGS(develop,                                         \
 141                            develop_pd,                                      \
 142                            product,                                         \
 143                            product_pd,                                      \
 144                            notproduct,                                      \
 145                            range,                                           \
 146                            constraint)
 147 const bool UseCompressedOops = false;
 148 const bool UseCompressedClassPointers = false;
 149 const intx ObjectAlignmentInBytes = 8;
 150 
 151 #endif // _LP64
 152 
 153 #define RUNTIME_FLAGS(develop,                                              \
 154                       develop_pd,                                           \
 155                       product,                                              \
 156                       product_pd,                                           \
 157                       notproduct,                                           \
 158                       range,                                                \
 159                       constraint)                                           \
 160                                                                             \
 161   notproduct(bool, CheckCompressedOops, true,                               \
 162           "Generate checks in encoding/decoding code in debug VM")          \
 163                                                                             \
 164   product(uintx, HeapSearchSteps, 3 PPC64_ONLY(+17),                        \
 165           "Heap allocation steps through preferred address regions to find" \
 166           " where it can allocate the heap. Number of steps to take per "   \
 167           "region.")                                                        \
 168           range(1, max_uintx)                                               \
 169                                                                             \
 170   product(uint, HandshakeTimeout, 0, DIAGNOSTIC,                            \
 171           "If nonzero set a timeout in milliseconds for handshakes")        \
 172                                                                             \
 173   product(bool, AlwaysSafeConstructors, false, EXPERIMENTAL,                \
 174           "Force safe construction, as if all fields are final.")           \
 175                                                                             \
 176   product(bool, UnlockDiagnosticVMOptions, trueInDebug, DIAGNOSTIC,         \
 177           "Enable normal processing of flags relating to field diagnostics")\
 178                                                                             \
 179   product(bool, UnlockExperimentalVMOptions, false, EXPERIMENTAL,           \
 180           "Enable normal processing of flags relating to experimental "     \
 181           "features")                                                       \
 182                                                                             \
 183   product(bool, JavaMonitorsInStackTrace, true,                             \
 184           "Print information about Java monitor locks when the stacks are " \
 185           "dumped")                                                         \
 186                                                                             \
 187   product_pd(bool, UseLargePages,                                           \
 188           "Use large page memory")                                          \
 189                                                                             \
 190   product_pd(bool, UseLargePagesIndividualAllocation,                       \
 191           "Allocate large pages individually for better affinity")          \
 192                                                                             \
 193   develop(bool, LargePagesIndividualAllocationInjectError, false,           \
 194           "Fail large pages individual allocation")                         \
 195                                                                             \
 196   product(bool, UseNUMA, false,                                             \
 197           "Use NUMA if available")                                          \
 198                                                                             \
 199   product(bool, UseNUMAInterleaving, false,                                 \
 200           "Interleave memory across NUMA nodes if available")               \
 201                                                                             \
 202   product(size_t, NUMAInterleaveGranularity, 2*M,                           \
 203           "Granularity to use for NUMA interleaving on Windows OS")         \
 204           constraint(NUMAInterleaveGranularityConstraintFunc, AtParse)      \
 205                                                                             \
 206   product(uintx, NUMAChunkResizeWeight, 20,                                 \
 207           "Percentage (0-100) used to weight the current sample when "      \
 208           "computing exponentially decaying average for "                   \
 209           "AdaptiveNUMAChunkSizing")                                        \
 210           range(0, 100)                                                     \
 211                                                                             \
 212   product(size_t, NUMASpaceResizeRate, 1*G,                                 \
 213           "Do not reallocate more than this amount per collection")         \
 214           range(0, max_uintx)                                               \
 215                                                                             \
 216   product(bool, UseAdaptiveNUMAChunkSizing, true,                           \
 217           "Enable adaptive chunk sizing for NUMA")                          \
 218                                                                             \
 219   product(bool, NUMAStats, false,                                           \
 220           "Print NUMA stats in detailed heap information")                  \
 221                                                                             \
 222   product(uintx, NUMAPageScanRate, 256,                                     \
 223           "Maximum number of pages to include in the page scan procedure")  \
 224           range(0, max_uintx)                                               \
 225                                                                             \
 226   product(bool, UseAES, false,                                              \
 227           "Control whether AES instructions are used when available")       \
 228                                                                             \
 229   product(bool, UseFMA, false,                                              \
 230           "Control whether FMA instructions are used when available")       \
 231                                                                             \
 232   product(bool, UseSHA, false,                                              \
 233           "Control whether SHA instructions are used when available")       \
 234                                                                             \
 235   product(bool, UseGHASHIntrinsics, false, DIAGNOSTIC,                      \
 236           "Use intrinsics for GHASH versions of crypto")                    \
 237                                                                             \
 238   product(bool, UseBASE64Intrinsics, false,                                 \
 239           "Use intrinsics for java.util.Base64")                            \
 240                                                                             \
 241   product(size_t, LargePageSizeInBytes, 0,                                  \
 242           "Maximum large page size used (0 will use the default large "     \
 243           "page size for the environment as the maximum)")                  \
 244           range(0, max_uintx)                                               \
 245                                                                             \
 246   product(size_t, LargePageHeapSizeThreshold, 128*M,                        \
 247           "Use large pages if maximum heap is at least this big")           \
 248           range(0, max_uintx)                                               \
 249                                                                             \
 250   product(bool, ForceTimeHighResolution, false,                             \
 251           "Using high time resolution (for Win32 only)")                    \
 252                                                                             \
 253   develop(bool, TracePcPatching, false,                                     \
 254           "Trace usage of frame::patch_pc")                                 \
 255                                                                             \
 256   develop(bool, TraceRelocator, false,                                      \
 257           "Trace the bytecode relocator")                                   \
 258                                                                             \
 259                                                                             \
 260   product(bool, SafepointALot, false, DIAGNOSTIC,                           \
 261           "Generate a lot of safepoints. This works with "                  \
 262           "GuaranteedSafepointInterval")                                    \
 263                                                                             \
 264   product(bool, HandshakeALot, false, DIAGNOSTIC,                           \
 265           "Generate a lot of handshakes. This works with "                  \
 266           "GuaranteedSafepointInterval")                                    \
 267                                                                             \
 268   product_pd(bool, BackgroundCompilation,                                   \
 269           "A thread requesting compilation is not blocked during "          \
 270           "compilation")                                                    \
 271                                                                             \
 272   product(bool, MethodFlushing, true,                                       \
 273           "Reclamation of zombie and not-entrant methods")                  \
 274                                                                             \
 275   develop(bool, VerifyStack, false,                                         \
 276           "Verify stack of each thread when it is entering a runtime call") \
 277                                                                             \
 278   product(bool, ForceUnreachable, false, DIAGNOSTIC,                        \
 279           "Make all non code cache addresses to be unreachable by "         \
 280           "forcing use of 64bit literal fixups")                            \
 281                                                                             \
 282   develop(bool, TraceDerivedPointers, false,                                \
 283           "Trace traversal of derived pointers on stack")                   \
 284                                                                             \
 285   notproduct(bool, TraceCodeBlobStacks, false,                              \
 286           "Trace stack-walk of codeblobs")                                  \
 287                                                                             \
 288   notproduct(bool, PrintRewrites, false,                                    \
 289           "Print methods that are being rewritten")                         \
 290                                                                             \
 291   product(bool, UseInlineCaches, true,                                      \
 292           "Use Inline Caches for virtual calls ")                           \
 293                                                                             \
 294   product(bool, InlineArrayCopy, true, DIAGNOSTIC,                          \
 295           "Inline arraycopy native that is known to be part of "            \
 296           "base library DLL")                                               \
 297                                                                             \
 298   product(bool, InlineObjectHash, true, DIAGNOSTIC,                         \
 299           "Inline Object::hashCode() native that is known to be part "      \
 300           "of base library DLL")                                            \
 301                                                                             \
 302   product(bool, InlineNatives, true, DIAGNOSTIC,                            \
 303           "Inline natives that are known to be part of base library DLL")   \
 304                                                                             \
 305   product(bool, InlineMathNatives, true, DIAGNOSTIC,                        \
 306           "Inline SinD, CosD, etc.")                                        \
 307                                                                             \
 308   product(bool, InlineClassNatives, true, DIAGNOSTIC,                       \
 309           "Inline Class.isInstance, etc")                                   \
 310                                                                             \
 311   product(bool, InlineThreadNatives, true, DIAGNOSTIC,                      \
 312           "Inline Thread.currentThread, etc")                               \
 313                                                                             \
 314   product(bool, InlineUnsafeOps, true, DIAGNOSTIC,                          \
 315           "Inline memory ops (native methods) from Unsafe")                 \
 316                                                                             \
 317   product(bool, CriticalJNINatives, false,                                  \
 318           "(Deprecated) Check for critical JNI entry points")               \
 319                                                                             \
 320   product(bool, UseAESIntrinsics, false, DIAGNOSTIC,                        \
 321           "Use intrinsics for AES versions of crypto")                      \
 322                                                                             \
 323   product(bool, UseAESCTRIntrinsics, false, DIAGNOSTIC,                     \
 324           "Use intrinsics for the paralleled version of AES/CTR crypto")    \
 325                                                                             \
 326   product(bool, UseMD5Intrinsics, false, DIAGNOSTIC,                        \
 327           "Use intrinsics for MD5 crypto hash function")                    \
 328                                                                             \
 329   product(bool, UseSHA1Intrinsics, false, DIAGNOSTIC,                       \
 330           "Use intrinsics for SHA-1 crypto hash function. "                 \
 331           "Requires that UseSHA is enabled.")                               \
 332                                                                             \
 333   product(bool, UseSHA256Intrinsics, false, DIAGNOSTIC,                     \
 334           "Use intrinsics for SHA-224 and SHA-256 crypto hash functions. "  \
 335           "Requires that UseSHA is enabled.")                               \
 336                                                                             \
 337   product(bool, UseSHA512Intrinsics, false, DIAGNOSTIC,                     \
 338           "Use intrinsics for SHA-384 and SHA-512 crypto hash functions. "  \
 339           "Requires that UseSHA is enabled.")                               \
 340                                                                             \
 341   product(bool, UseSHA3Intrinsics, false, DIAGNOSTIC,                       \
 342           "Use intrinsics for SHA3 crypto hash function. "                  \
 343           "Requires that UseSHA is enabled.")                               \
 344                                                                             \
 345   product(bool, UseCRC32Intrinsics, false, DIAGNOSTIC,                      \
 346           "use intrinsics for java.util.zip.CRC32")                         \
 347                                                                             \
 348   product(bool, UseCRC32CIntrinsics, false, DIAGNOSTIC,                     \
 349           "use intrinsics for java.util.zip.CRC32C")                        \
 350                                                                             \
 351   product(bool, UseAdler32Intrinsics, false, DIAGNOSTIC,                    \
 352           "use intrinsics for java.util.zip.Adler32")                       \
 353                                                                             \
 354   product(bool, UseVectorizedMismatchIntrinsic, false, DIAGNOSTIC,          \
 355           "Enables intrinsification of ArraysSupport.vectorizedMismatch()") \
 356                                                                             \
 357   product(bool, UseCopySignIntrinsic, false, DIAGNOSTIC,                    \
 358           "Enables intrinsification of Math.copySign")                      \
 359                                                                             \
 360   product(bool, UseSignumIntrinsic, false, DIAGNOSTIC,                      \
 361           "Enables intrinsification of Math.signum")                        \
 362                                                                             \
 363   product(ccstrlist, DisableIntrinsic, "", DIAGNOSTIC,                      \
 364          "do not expand intrinsics whose (internal) names appear here")     \
 365          constraint(DisableIntrinsicConstraintFunc,AfterErgo)               \
 366                                                                             \
 367   product(ccstrlist, ControlIntrinsic, "", DIAGNOSTIC,                      \
 368          "Control intrinsics using a list of +/- (internal) names, "        \
 369          "separated by commas")                                             \
 370          constraint(ControlIntrinsicConstraintFunc,AfterErgo)               \
 371                                                                             \
 372   develop(bool, TraceCallFixup, false,                                      \
 373           "Trace all call fixups")                                          \
 374                                                                             \
 375   develop(bool, DeoptimizeALot, false,                                      \
 376           "Deoptimize at every exit from the runtime system")               \
 377                                                                             \
 378   notproduct(ccstrlist, DeoptimizeOnlyAt, "",                               \
 379           "A comma separated list of bcis to deoptimize at")                \
 380                                                                             \
 381   develop(bool, DeoptimizeRandom, false,                                    \
 382           "Deoptimize random frames on random exit from the runtime system")\
 383                                                                             \
 384   notproduct(bool, ZombieALot, false,                                       \
 385           "Create zombies (non-entrant) at exit from the runtime system")   \
 386                                                                             \
 387   notproduct(bool, WalkStackALot, false,                                    \
 388           "Trace stack (no print) at every exit from the runtime system")   \
 389                                                                             \
 390   develop(bool, DeoptimizeObjectsALot, false,                               \
 391           "For testing purposes concurrent threads revert optimizations "   \
 392           "based on escape analysis at intervals given with "               \
 393           "DeoptimizeObjectsALotInterval=n. The thread count is given "     \
 394           "with DeoptimizeObjectsALotThreadCountSingle and "                \
 395           "DeoptimizeObjectsALotThreadCountAll.")                           \
 396                                                                             \
 397   develop(uint64_t, DeoptimizeObjectsALotInterval, 5,                       \
 398           "Interval for DeoptimizeObjectsALot.")                            \
 399           range(0, max_jlong)                                               \
 400                                                                             \
 401   develop(int, DeoptimizeObjectsALotThreadCountSingle, 1,                   \
 402           "The number of threads that revert optimizations based on "       \
 403           "escape analysis for a single thread if DeoptimizeObjectsALot "   \
 404           "is enabled. The target thread is selected round robin." )        \
 405           range(0, max_jint)                                                \
 406                                                                             \
 407   develop(int, DeoptimizeObjectsALotThreadCountAll, 1,                      \
 408           "The number of threads that revert optimizations based on "       \
 409           "escape analysis for all threads if DeoptimizeObjectsALot "       \
 410           "is enabled." )                                                   \
 411           range(0, max_jint)                                                \
 412                                                                             \
 413   notproduct(bool, VerifyLastFrame, false,                                  \
 414           "Verify oops on last frame on entry to VM")                       \
 415                                                                             \
 416   product(bool, SafepointTimeout, false,                                    \
 417           "Time out and warn or fail after SafepointTimeoutDelay "          \
 418           "milliseconds if failed to reach safepoint")                      \
 419                                                                             \
 420   product(bool, AbortVMOnSafepointTimeout, false, DIAGNOSTIC,               \
 421           "Abort upon failure to reach safepoint (see SafepointTimeout)")   \
 422                                                                             \
 423   product(bool, AbortVMOnVMOperationTimeout, false, DIAGNOSTIC,             \
 424           "Abort upon failure to complete VM operation promptly")           \
 425                                                                             \
 426   product(intx, AbortVMOnVMOperationTimeoutDelay, 1000, DIAGNOSTIC,         \
 427           "Delay in milliseconds for option AbortVMOnVMOperationTimeout")   \
 428           range(0, max_intx)                                                \
 429                                                                             \
 430   product(bool, MaxFDLimit, true,                                           \
 431           "Bump the number of file descriptors to maximum (Unix only)")     \
 432                                                                             \
 433   product(bool, LogEvents, true, DIAGNOSTIC,                                \
 434           "Enable the various ring buffer event logs")                      \
 435                                                                             \
 436   product(uintx, LogEventsBufferEntries, 20, DIAGNOSTIC,                    \
 437           "Number of ring buffer event logs")                               \
 438           range(1, NOT_LP64(1*K) LP64_ONLY(1*M))                            \
 439                                                                             \
 440   product(bool, BytecodeVerificationRemote, true, DIAGNOSTIC,               \
 441           "Enable the Java bytecode verifier for remote classes")           \
 442                                                                             \
 443   product(bool, BytecodeVerificationLocal, false, DIAGNOSTIC,               \
 444           "Enable the Java bytecode verifier for local classes")            \
 445                                                                             \
 446   develop(bool, VerifyStackAtCalls, false,                                  \
 447           "Verify that the stack pointer is unchanged after calls")         \
 448                                                                             \
 449   develop(bool, TraceJavaAssertions, false,                                 \
 450           "Trace java language assertions")                                 \
 451                                                                             \
 452   notproduct(bool, VerifyCodeCache, false,                                  \
 453           "Verify code cache on memory allocation/deallocation")            \
 454                                                                             \
 455   develop(bool, UseMallocOnly, false,                                       \
 456           "Use only malloc/free for allocation (no resource area/arena)")   \
 457                                                                             \
 458   develop(bool, ZapResourceArea, trueInDebug,                               \
 459           "Zap freed resource/arena space")                                 \
 460                                                                             \
 461   notproduct(bool, ZapVMHandleArea, trueInDebug,                            \
 462           "Zap freed VM handle space")                                      \
 463                                                                             \
 464   notproduct(bool, ZapStackSegments, trueInDebug,                           \
 465           "Zap allocated/freed stack segments")                             \
 466                                                                             \
 467   develop(bool, ZapUnusedHeapArea, trueInDebug,                             \
 468           "Zap unused heap space")                                          \
 469                                                                             \
 470   develop(bool, CheckZapUnusedHeapArea, false,                              \
 471           "Check zapping of unused heap space")                             \
 472                                                                             \
 473   develop(bool, ZapFillerObjects, trueInDebug,                              \
 474           "Zap filler objects")                                             \
 475                                                                             \
 476   product(bool, ExecutingUnitTests, false,                                  \
 477           "Whether the JVM is running unit tests or not")                   \
 478                                                                             \
 479   develop(uintx, ErrorHandlerTest, 0,                                       \
 480           "If > 0, provokes an error after VM initialization; the value "   \
 481           "determines which error to provoke. See controlled_crash() "      \
 482           "in vmError.cpp.")                                                \
 483           range(0, 17)                                                      \
 484                                                                             \
 485   develop(uintx, TestCrashInErrorHandler, 0,                                \
 486           "If > 0, provokes an error inside VM error handler (a secondary " \
 487           "crash). see controlled_crash() in vmError.cpp")                  \
 488           range(0, 17)                                                      \
 489                                                                             \
 490   develop(bool, TestSafeFetchInErrorHandler, false   ,                      \
 491           "If true, tests SafeFetch inside error handler.")                 \
 492                                                                             \
 493   develop(bool, TestUnresponsiveErrorHandler, false,                        \
 494           "If true, simulates an unresponsive error handler.")              \
 495                                                                             \
 496   develop(bool, Verbose, false,                                             \
 497           "Print additional debugging information from other modes")        \
 498                                                                             \
 499   develop(bool, PrintMiscellaneous, false,                                  \
 500           "Print uncategorized debugging information (requires +Verbose)")  \
 501                                                                             \
 502   develop(bool, WizardMode, false,                                          \
 503           "Print much more debugging information")                          \
 504                                                                             \
 505   product(bool, ShowMessageBoxOnError, false,                               \
 506           "Keep process alive on VM fatal error")                           \
 507                                                                             \
 508   product(bool, CreateCoredumpOnCrash, true,                                \
 509           "Create core/mini dump on VM fatal error")                        \
 510                                                                             \
 511   product(uint64_t, ErrorLogTimeout, 2 * 60,                                \
 512           "Timeout, in seconds, to limit the time spent on writing an "     \
 513           "error log in case of a crash.")                                  \
 514           range(0, (uint64_t)max_jlong/1000)                                \
 515                                                                             \
 516   product(bool, SuppressFatalErrorMessage, false,                           \
 517           "Report NO fatal error message (avoid deadlock)")                 \
 518                                                                             \
 519   product(ccstrlist, OnError, "",                                           \
 520           "Run user-defined commands on fatal error; see VMError.cpp "      \
 521           "for examples")                                                   \
 522                                                                             \
 523   product(ccstrlist, OnOutOfMemoryError, "",                                \
 524           "Run user-defined commands on first java.lang.OutOfMemoryError "  \
 525           "thrown from JVM")                                                \
 526                                                                             \
 527   product(bool, HeapDumpBeforeFullGC, false, MANAGEABLE,                    \
 528           "Dump heap to file before any major stop-the-world GC")           \
 529                                                                             \
 530   product(bool, HeapDumpAfterFullGC, false, MANAGEABLE,                     \
 531           "Dump heap to file after any major stop-the-world GC")            \
 532                                                                             \
 533   product(bool, HeapDumpOnOutOfMemoryError, false, MANAGEABLE,              \
 534           "Dump heap to file when java.lang.OutOfMemoryError is thrown "    \
 535           "from JVM")                                                       \
 536                                                                             \
 537   product(ccstr, HeapDumpPath, NULL, MANAGEABLE,                            \
 538           "When HeapDumpOnOutOfMemoryError is on, the path (filename or "   \
 539           "directory) of the dump file (defaults to java_pid<pid>.hprof "   \
 540           "in the working directory)")                                      \
 541                                                                             \
 542   product(intx, HeapDumpGzipLevel, 0, MANAGEABLE,                           \
 543           "When HeapDumpOnOutOfMemoryError is on, the gzip compression "    \
 544           "level of the dump file. 0 (the default) disables gzip "          \
 545           "compression. Otherwise the level must be between 1 and 9.")      \
 546           range(0, 9)                                                       \
 547                                                                             \
 548   product(ccstr, NativeMemoryTracking, DEBUG_ONLY("summary") NOT_DEBUG("off"), \
 549           "Native memory tracking options")                                 \
 550                                                                             \
 551   product(bool, PrintNMTStatistics, false, DIAGNOSTIC,                      \
 552           "Print native memory tracking summary data if it is on")          \
 553                                                                             \
 554   product(bool, LogCompilation, false, DIAGNOSTIC,                          \
 555           "Log compilation activity in detail to LogFile")                  \
 556                                                                             \
 557   product(bool, PrintCompilation, false,                                    \
 558           "Print compilations")                                             \
 559                                                                             \
 560   product(intx, RepeatCompilation, 0, DIAGNOSTIC,                           \
 561           "Repeat compilation without installing code (number of times)")   \
 562           range(0, max_jint)                                                \
 563                                                                             \
 564   product(bool, PrintExtendedThreadInfo, false,                             \
 565           "Print more information in thread dump")                          \
 566                                                                             \
 567   product(intx, ScavengeRootsInCode, 2, DIAGNOSTIC,                         \
 568           "0: do not allow scavengable oops in the code cache; "            \
 569           "1: allow scavenging from the code cache; "                       \
 570           "2: emit as many constants as the compiler can see")              \
 571           range(0, 2)                                                       \
 572                                                                             \
 573   product(bool, AlwaysRestoreFPU, false,                                    \
 574           "Restore the FPU control word after every JNI call (expensive)")  \
 575                                                                             \
 576   product(bool, PrintCompilation2, false, DIAGNOSTIC,                       \
 577           "Print additional statistics per compilation")                    \
 578                                                                             \
 579   product(bool, PrintAdapterHandlers, false, DIAGNOSTIC,                    \
 580           "Print code generated for i2c/c2i adapters")                      \
 581                                                                             \
 582   product(bool, VerifyAdapterCalls, trueInDebug, DIAGNOSTIC,                \
 583           "Verify that i2c/c2i adapters are called properly")               \
 584                                                                             \
 585   develop(bool, VerifyAdapterSharing, false,                                \
 586           "Verify that the code for shared adapters is the equivalent")     \
 587                                                                             \
 588   product(bool, PrintAssembly, false, DIAGNOSTIC,                           \
 589           "Print assembly code (using external disassembler.so)")           \
 590                                                                             \
 591   product(ccstr, PrintAssemblyOptions, NULL, DIAGNOSTIC,                    \
 592           "Print options string passed to disassembler.so")                 \
 593                                                                             \
 594   notproduct(bool, PrintNMethodStatistics, false,                           \
 595           "Print a summary statistic for the generated nmethods")           \
 596                                                                             \
 597   product(bool, PrintNMethods, false, DIAGNOSTIC,                           \
 598           "Print assembly code for nmethods when generated")                \
 599                                                                             \
 600   product(bool, PrintNativeNMethods, false, DIAGNOSTIC,                     \
 601           "Print assembly code for native nmethods when generated")         \
 602                                                                             \
 603   develop(bool, PrintDebugInfo, false,                                      \
 604           "Print debug information for all nmethods when generated")        \
 605                                                                             \
 606   develop(bool, PrintRelocations, false,                                    \
 607           "Print relocation information for all nmethods when generated")   \
 608                                                                             \
 609   develop(bool, PrintDependencies, false,                                   \
 610           "Print dependency information for all nmethods when generated")   \
 611                                                                             \
 612   develop(bool, PrintExceptionHandlers, false,                              \
 613           "Print exception handler tables for all nmethods when generated") \
 614                                                                             \
 615   develop(bool, StressCompiledExceptionHandlers, false,                     \
 616           "Exercise compiled exception handlers")                           \
 617                                                                             \
 618   develop(bool, InterceptOSException, false,                                \
 619           "Start debugger when an implicit OS (e.g. NULL) "                 \
 620           "exception happens")                                              \
 621                                                                             \
 622   product(bool, PrintCodeCache, false,                                      \
 623           "Print the code cache memory usage when exiting")                 \
 624                                                                             \
 625   develop(bool, PrintCodeCache2, false,                                     \
 626           "Print detailed usage information on the code cache when exiting")\
 627                                                                             \
 628   product(bool, PrintCodeCacheOnCompilation, false,                         \
 629           "Print the code cache memory usage each time a method is "        \
 630           "compiled")                                                       \
 631                                                                             \
 632   product(bool, PrintCodeHeapAnalytics, false, DIAGNOSTIC,                  \
 633           "Print code heap usage statistics on exit and on full condition") \
 634                                                                             \
 635   product(bool, PrintStubCode, false, DIAGNOSTIC,                           \
 636           "Print generated stub code")                                      \
 637                                                                             \
 638   product(bool, StackTraceInThrowable, true,                                \
 639           "Collect backtrace in throwable when exception happens")          \
 640                                                                             \
 641   product(bool, OmitStackTraceInFastThrow, true,                            \
 642           "Omit backtraces for some 'hot' exceptions in optimized code")    \
 643                                                                             \
 644   product(bool, ShowCodeDetailsInExceptionMessages, true, MANAGEABLE,       \
 645           "Show exception messages from RuntimeExceptions that contain "    \
 646           "snippets of the failing code. Disable this to improve privacy.") \
 647                                                                             \
 648   product(bool, PrintWarnings, true,                                        \
 649           "Print JVM warnings to output stream")                            \
 650                                                                             \
 651   product(bool, RegisterFinalizersAtInit, true,                             \
 652           "Register finalizable objects at end of Object.<init> or "        \
 653           "after allocation")                                               \
 654                                                                             \
 655   develop(bool, RegisterReferences, true,                                   \
 656           "Tell whether the VM should register soft/weak/final/phantom "    \
 657           "references")                                                     \
 658                                                                             \
 659   develop(bool, PrintCodeCacheExtension, false,                             \
 660           "Print extension of code cache")                                  \
 661                                                                             \
 662   develop(bool, UsePrivilegedStack, true,                                   \
 663           "Enable the security JVM functions")                              \
 664                                                                             \
 665   product(bool, ClassUnloading, true,                                       \
 666           "Do unloading of classes")                                        \
 667                                                                             \
 668   product(bool, ClassUnloadingWithConcurrentMark, true,                     \
 669           "Do unloading of classes with a concurrent marking cycle")        \
 670                                                                             \
 671   notproduct(bool, PrintSystemDictionaryAtExit, false,                      \
 672           "Print the system dictionary at exit")                            \
 673                                                                             \
 674   notproduct(bool, PrintClassLoaderDataGraphAtExit, false,                  \
 675           "Print the class loader data graph at exit")                      \
 676                                                                             \
 677   product(bool, DynamicallyResizeSystemDictionaries, true, DIAGNOSTIC,      \
 678           "Dynamically resize system dictionaries as needed")               \
 679                                                                             \
 680   product(bool, AlwaysLockClassLoader, false,                               \
 681           "(Deprecated) Require the VM to acquire the class loader lock "   \
 682           "before calling loadClass() even for class loaders registering "  \
 683           "as parallel capable")                                            \
 684                                                                             \
 685   product(bool, AllowParallelDefineClass, false,                            \
 686           "Allow parallel defineClass requests for class loaders "          \
 687           "registering as parallel capable")                                \
 688                                                                             \
 689   product_pd(bool, DontYieldALot,                                           \
 690           "Throw away obvious excess yield calls")                          \
 691                                                                             \
 692   product(bool, DisablePrimordialThreadGuardPages, false, EXPERIMENTAL,     \
 693                "Disable the use of stack guard pages if the JVM is loaded " \
 694                "on the primordial process thread")                          \
 695                                                                             \
 696   /* notice: the max range value here is max_jint, not max_intx  */         \
 697   /* because of overflow issue                                   */         \
 698   product(intx, AsyncDeflationInterval, 250, DIAGNOSTIC,                    \
 699           "Async deflate idle monitors every so many milliseconds when "    \
 700           "MonitorUsedDeflationThreshold is exceeded (0 is off).")          \
 701           range(0, max_jint)                                                \
 702                                                                             \
 703   product(size_t, AvgMonitorsPerThreadEstimate, 1024, DIAGNOSTIC,           \
 704           "Used to estimate a variable ceiling based on number of threads " \
 705           "for use with MonitorUsedDeflationThreshold (0 is off).")         \
 706           range(0, max_uintx)                                               \
 707                                                                             \
 708   /* notice: the max range value here is max_jint, not max_intx  */         \
 709   /* because of overflow issue                                   */         \
 710   product(intx, MonitorDeflationMax, 1000000, DIAGNOSTIC,                   \
 711           "The maximum number of monitors to deflate, unlink and delete "   \
 712           "at one time (minimum is 1024).")                      \
 713           range(1024, max_jint)                                             \
 714                                                                             \
 715   product(intx, MonitorUsedDeflationThreshold, 90, DIAGNOSTIC,              \
 716           "Percentage of used monitors before triggering deflation (0 is "  \
 717           "off). The check is performed on GuaranteedSafepointInterval "    \
 718           "or AsyncDeflationInterval.")                                     \
 719           range(0, 100)                                                     \
 720                                                                             \
 721   product(uintx, NoAsyncDeflationProgressMax, 3, DIAGNOSTIC,                \
 722           "Max number of no progress async deflation attempts to tolerate " \
 723           "before adjusting the in_use_list_ceiling up (0 is off).")        \
 724           range(0, max_uintx)                                               \
 725                                                                             \
 726   product(intx, hashCode, 5, EXPERIMENTAL,                                  \
 727                "(Unstable) select hashCode generation algorithm")           \
 728                                                                             \
 729   product(bool, FilterSpuriousWakeups, true,                                \
 730           "When true prevents OS-level spurious, or premature, wakeups "    \
 731           "from Object.wait (Ignored for Windows)")                         \
 732                                                                             \
 733   product(bool, ReduceSignalUsage, false,                                   \
 734           "Reduce the use of OS signals in Java and/or the VM")             \
 735                                                                             \
 736   develop(bool, LoadLineNumberTables, true,                                 \
 737           "Tell whether the class file parser loads line number tables")    \
 738                                                                             \
 739   develop(bool, LoadLocalVariableTables, true,                              \
 740           "Tell whether the class file parser loads local variable tables") \
 741                                                                             \
 742   develop(bool, LoadLocalVariableTypeTables, true,                          \
 743           "Tell whether the class file parser loads local variable type"    \
 744           "tables")                                                         \
 745                                                                             \
 746   product(bool, AllowUserSignalHandlers, false,                             \
 747           "Application will install primary signal handlers for the JVM "   \
 748           "(Unix only)")                                                    \
 749                                                                             \
 750   product(bool, UseSignalChaining, true,                                    \
 751           "Use signal-chaining to invoke signal handlers installed "        \
 752           "by the application (Unix only)")                                 \
 753                                                                             \
 754   product(bool, RestoreMXCSROnJNICalls, false,                              \
 755           "Restore MXCSR when returning from JNI calls")                    \
 756                                                                             \
 757   product(bool, CheckJNICalls, false,                                       \
 758           "Verify all arguments to JNI calls")                              \
 759                                                                             \
 760   product(bool, UseFastJNIAccessors, true,                                  \
 761           "Use optimized versions of Get<Primitive>Field")                  \
 762                                                                             \
 763   product(intx, MaxJNILocalCapacity, 65536,                                 \
 764           "Maximum allowable local JNI handle capacity to "                 \
 765           "EnsureLocalCapacity() and PushLocalFrame(), "                    \
 766           "where <= 0 is unlimited, default: 65536")                        \
 767           range(min_intx, max_intx)                                         \
 768                                                                             \
 769   product(bool, EagerXrunInit, false,                                       \
 770           "Eagerly initialize -Xrun libraries; allows startup profiling, "  \
 771           "but not all -Xrun libraries may support the state of the VM "    \
 772           "at this time")                                                   \
 773                                                                             \
 774   product(bool, PreserveAllAnnotations, false,                              \
 775           "Preserve RuntimeInvisibleAnnotations as well "                   \
 776           "as RuntimeVisibleAnnotations")                                   \
 777                                                                             \
 778   develop(uintx, PreallocatedOutOfMemoryErrorCount, 4,                      \
 779           "Number of OutOfMemoryErrors preallocated with backtrace")        \
 780                                                                             \
 781   product(bool, UseXMMForArrayCopy, false,                                  \
 782           "Use SSE2 MOVQ instruction for Arraycopy")                        \
 783                                                                             \
 784   notproduct(bool, PrintFieldLayout, false,                                 \
 785           "Print field layout for each class")                              \
 786                                                                             \
 787   /* Need to limit the extent of the padding to reasonable size.          */\
 788   /* 8K is well beyond the reasonable HW cache line size, even with       */\
 789   /* aggressive prefetching, while still leaving the room for segregating */\
 790   /* among the distinct pages.                                            */\
 791   product(intx, ContendedPaddingWidth, 128,                                 \
 792           "How many bytes to pad the fields/classes marked @Contended with")\
 793           range(0, 8192)                                                    \
 794           constraint(ContendedPaddingWidthConstraintFunc,AfterErgo)         \
 795                                                                             \
 796   product(bool, EnableContended, true,                                      \
 797           "Enable @Contended annotation support")                           \
 798                                                                             \
 799   product(bool, RestrictContended, true,                                    \
 800           "Restrict @Contended to trusted classes")                         \
 801                                                                             \
 802   product(bool, UseBiasedLocking, false,                                    \
 803           "(Deprecated) Enable biased locking in JVM")                      \
 804                                                                             \
 805   product(intx, BiasedLockingStartupDelay, 0,                               \
 806           "(Deprecated) Number of milliseconds to wait before enabling "    \
 807           "biased locking")                                                 \
 808           range(0, (intx)(max_jint-(max_jint%PeriodicTask::interval_gran))) \
 809           constraint(BiasedLockingStartupDelayFunc,AfterErgo)               \
 810                                                                             \
 811   product(bool, PrintBiasedLockingStatistics, false, DIAGNOSTIC,            \
 812           "(Deprecated) Print statistics of biased locking in JVM")         \
 813                                                                             \
 814   product(intx, BiasedLockingBulkRebiasThreshold, 20,                       \
 815           "(Deprecated) Threshold of number of revocations per type to "    \
 816           "try to rebias all objects in the heap of that type")             \
 817           range(0, max_intx)                                                \
 818           constraint(BiasedLockingBulkRebiasThresholdFunc,AfterErgo)        \
 819                                                                             \
 820   product(intx, BiasedLockingBulkRevokeThreshold, 40,                       \
 821           "(Deprecated) Threshold of number of revocations per type to "    \
 822           "permanently revoke biases of all objects in the heap of that "   \
 823           "type")                                                           \
 824           range(0, max_intx)                                                \
 825           constraint(BiasedLockingBulkRevokeThresholdFunc,AfterErgo)        \
 826                                                                             \
 827   product(intx, BiasedLockingDecayTime, 25000,                              \
 828           "(Deprecated) Decay time (in milliseconds) to re-enable bulk "    \
 829           "rebiasing of a type after previous bulk rebias")                 \
 830           range(500, max_intx)                                              \
 831           constraint(BiasedLockingDecayTimeFunc,AfterErgo)                  \
 832                                                                             \
 833   product(intx, DiagnoseSyncOnValueBasedClasses, 0, DIAGNOSTIC,             \
 834              "Detect and take action upon identifying synchronization on "  \
 835              "value based classes. Modes: "                                 \
 836              "0: off; "                                                     \
 837              "1: exit with fatal error; "                                   \
 838              "2: log message to stdout. Output file can be specified with " \
 839              "   -Xlog:valuebasedclasses. If JFR is running it will "       \
 840              "   also generate JFR events.")                                \
 841              range(0, 2)                                                    \
 842                                                                             \
 843   product(bool, ExitOnOutOfMemoryError, false,                              \
 844           "JVM exits on the first occurrence of an out-of-memory error "    \
 845           "thrown from JVM")                                                \
 846                                                                             \
 847   product(bool, CrashOnOutOfMemoryError, false,                             \
 848           "JVM aborts, producing an error log and core/mini dump, on the "  \
 849           "first occurrence of an out-of-memory error thrown from JVM")     \
 850                                                                             \
 851   /* tracing */                                                             \
 852                                                                             \
 853   develop(bool, StressRewriter, false,                                      \
 854           "Stress linktime bytecode rewriting")                             \
 855                                                                             \
 856   product(ccstr, TraceJVMTI, NULL,                                          \
 857           "Trace flags for JVMTI functions and events")                     \
 858                                                                             \
 859   product(bool, StressLdcRewrite, false, DIAGNOSTIC,                        \
 860           "Force ldc -> ldc_w rewrite during RedefineClasses. "             \
 861           "This option can change an EMCP method into an obsolete method "  \
 862           "and can affect tests that expect specific methods to be EMCP. "  \
 863           "This option should be used with caution.")                       \
 864                                                                             \
 865   product(bool, AllowRedefinitionToAddDeleteMethods, false,                 \
 866           "(Deprecated) Allow redefinition to add and delete private "      \
 867           "static or final methods for compatibility with old releases")    \
 868                                                                             \
 869   develop(bool, TraceBytecodes, false,                                      \
 870           "Trace bytecode execution")                                       \
 871                                                                             \
 872   develop(bool, TraceICs, false,                                            \
 873           "Trace inline cache changes")                                     \
 874                                                                             \
 875   notproduct(bool, TraceInvocationCounterOverflow, false,                   \
 876           "Trace method invocation counter overflow")                       \
 877                                                                             \
 878   develop(bool, TraceInlineCacheClearing, false,                            \
 879           "Trace clearing of inline caches in nmethods")                    \
 880                                                                             \
 881   develop(bool, TraceDependencies, false,                                   \
 882           "Trace dependencies")                                             \
 883                                                                             \
 884   develop(bool, VerifyDependencies, trueInDebug,                            \
 885           "Exercise and verify the compilation dependency mechanism")       \
 886                                                                             \
 887   develop(bool, TraceNewOopMapGeneration, false,                            \
 888           "Trace OopMapGeneration")                                         \
 889                                                                             \
 890   develop(bool, TraceNewOopMapGenerationDetailed, false,                    \
 891           "Trace OopMapGeneration: print detailed cell states")             \
 892                                                                             \
 893   develop(bool, TimeOopMap, false,                                          \
 894           "Time calls to GenerateOopMap::compute_map() in sum")             \
 895                                                                             \
 896   develop(bool, TimeOopMap2, false,                                         \
 897           "Time calls to GenerateOopMap::compute_map() individually")       \
 898                                                                             \
 899   develop(bool, TraceOopMapRewrites, false,                                 \
 900           "Trace rewriting of methods during oop map generation")           \
 901                                                                             \
 902   develop(bool, TraceICBuffer, false,                                       \
 903           "Trace usage of IC buffer")                                       \
 904                                                                             \
 905   develop(bool, TraceCompiledIC, false,                                     \
 906           "Trace changes of compiled IC")                                   \
 907                                                                             \
 908   develop(bool, FLSVerifyDictionary, false,                                 \
 909           "Do lots of (expensive) FLS dictionary verification")             \
 910                                                                             \
 911                                                                             \
 912   notproduct(bool, CheckMemoryInitialization, false,                        \
 913           "Check memory initialization")                                    \
 914                                                                             \
 915   product(uintx, ProcessDistributionStride, 4,                              \
 916           "Stride through processors when distributing processes")          \
 917           range(0, max_juint)                                               \
 918                                                                             \
 919   develop(bool, TraceFinalizerRegistration, false,                          \
 920           "Trace registration of final references")                         \
 921                                                                             \
 922   product(bool, IgnoreEmptyClassPaths, false,                               \
 923           "Ignore empty path elements in -classpath")                       \
 924                                                                             \
 925   product(bool, PrintHeapAtSIGBREAK, true,                                  \
 926           "Print heap layout in response to SIGBREAK")                      \
 927                                                                             \
 928   product(bool, PrintClassHistogram, false, MANAGEABLE,                     \
 929           "Print a histogram of class instances")                           \
 930                                                                             \
 931   product(double, ObjectCountCutOffPercent, 0.5, EXPERIMENTAL,              \
 932           "The percentage of the used heap that the instances of a class "  \
 933           "must occupy for the class to generate a trace event")            \
 934           range(0.0, 100.0)                                                 \
 935                                                                             \
 936   /* JVMTI heap profiling */                                                \
 937                                                                             \
 938   product(bool, VerifyBeforeIteration, false, DIAGNOSTIC,                   \
 939           "Verify memory system before JVMTI iteration")                    \
 940                                                                             \
 941   /* compiler */                                                            \
 942                                                                             \
 943   /* notice: the max range value here is max_jint, not max_intx  */         \
 944   /* because of overflow issue                                   */         \
 945   product(intx, CICompilerCount, CI_COMPILER_COUNT,                         \
 946           "Number of compiler threads to run")                              \
 947           range(0, max_jint)                                                \
 948           constraint(CICompilerCountConstraintFunc, AfterErgo)              \
 949                                                                             \
 950   product(bool, UseDynamicNumberOfCompilerThreads, true,                    \
 951           "Dynamically choose the number of parallel compiler threads")     \
 952                                                                             \
 953   product(bool, ReduceNumberOfCompilerThreads, true, DIAGNOSTIC,            \
 954              "Reduce the number of parallel compiler threads when they "    \
 955              "are not used")                                                \
 956                                                                             \
 957   product(bool, TraceCompilerThreads, false, DIAGNOSTIC,                    \
 958              "Trace creation and removal of compiler threads")              \
 959                                                                             \
 960   develop(bool, InjectCompilerCreationFailure, false,                       \
 961           "Inject thread creation failures for "                            \
 962           "UseDynamicNumberOfCompilerThreads")                              \
 963                                                                             \
 964   develop(bool, GenerateSynchronizationCode, true,                          \
 965           "generate locking/unlocking code for synchronized methods and "   \
 966           "monitors")                                                       \
 967                                                                             \
 968   develop(bool, GenerateRangeChecks, true,                                  \
 969           "Generate range checks for array accesses")                       \
 970                                                                             \
 971   product_pd(bool, ImplicitNullChecks, DIAGNOSTIC,                          \
 972           "Generate code for implicit null checks")                         \
 973                                                                             \
 974   product_pd(bool, TrapBasedNullChecks,                                     \
 975           "Generate code for null checks that uses a cmp and trap "         \
 976           "instruction raising SIGTRAP.  This is only used if an access to" \
 977           "null (+offset) will not raise a SIGSEGV, i.e.,"                  \
 978           "ImplicitNullChecks don't work (PPC64).")                         \
 979                                                                             \
 980   product(bool, EnableThreadSMRExtraValidityChecks, true, DIAGNOSTIC,       \
 981              "Enable Thread SMR extra validity checks")                     \
 982                                                                             \
 983   product(bool, EnableThreadSMRStatistics, trueInDebug, DIAGNOSTIC,         \
 984              "Enable Thread SMR Statistics")                                \
 985                                                                             \
 986   product(bool, UseNotificationThread, true,                                \
 987           "Use Notification Thread")                                        \
 988                                                                             \
 989   product(bool, Inline, true,                                               \
 990           "Enable inlining")                                                \
 991                                                                             \
 992   product(bool, ClipInlining, true,                                         \
 993           "Clip inlining if aggregate method exceeds DesiredMethodLimit")   \
 994                                                                             \
 995   develop(bool, UseCHA, true,                                               \
 996           "Enable CHA")                                                     \
 997                                                                             \
 998   product(bool, UseVtableBasedCHA, true,  DIAGNOSTIC,                       \
 999           "Use vtable information during CHA")                              \
1000                                                                             \
1001   product(bool, UseTypeProfile, true,                                       \
1002           "Check interpreter profile for historically monomorphic calls")   \
1003                                                                             \
1004   product(bool, PrintInlining, false, DIAGNOSTIC,                           \
1005           "Print inlining optimizations")                                   \
1006                                                                             \
1007   product(bool, UsePopCountInstruction, false,                              \
1008           "Use population count instruction")                               \
1009                                                                             \
1010   develop(bool, EagerInitialization, false,                                 \
1011           "Eagerly initialize classes if possible")                         \
1012                                                                             \
1013   product(bool, LogTouchedMethods, false, DIAGNOSTIC,                       \
1014           "Log methods which have been ever touched in runtime")            \
1015                                                                             \
1016   product(bool, PrintTouchedMethodsAtExit, false, DIAGNOSTIC,               \
1017           "Print all methods that have been ever touched in runtime")       \
1018                                                                             \
1019   develop(bool, TraceMethodReplacement, false,                              \
1020           "Print when methods are replaced do to recompilation")            \
1021                                                                             \
1022   develop(bool, PrintMethodFlushing, false,                                 \
1023           "Print the nmethods being flushed")                               \
1024                                                                             \
1025   product(bool, PrintMethodFlushingStatistics, false, DIAGNOSTIC,           \
1026           "print statistics about method flushing")                         \
1027                                                                             \
1028   product(intx, HotMethodDetectionLimit, 100000, DIAGNOSTIC,                \
1029           "Number of compiled code invocations after which "                \
1030           "the method is considered as hot by the flusher")                 \
1031           range(1, max_jint)                                                \
1032                                                                             \
1033   product(intx, MinPassesBeforeFlush, 10, DIAGNOSTIC,                       \
1034           "Minimum number of sweeper passes before an nmethod "             \
1035           "can be flushed")                                                 \
1036           range(0, max_intx)                                                \
1037                                                                             \
1038   product(bool, UseCodeAging, true,                                         \
1039           "Insert counter to detect warm methods")                          \
1040                                                                             \
1041   product(bool, StressCodeAging, false, DIAGNOSTIC,                         \
1042           "Start with counters compiled in")                                \
1043                                                                             \
1044   develop(bool, StressCodeBuffers, false,                                   \
1045           "Exercise code buffer expansion and other rare state changes")    \
1046                                                                             \
1047   product(bool, DebugNonSafepoints, trueInDebug, DIAGNOSTIC,                \
1048           "Generate extra debugging information for non-safepoints in "     \
1049           "nmethods")                                                       \
1050                                                                             \
1051   product(bool, PrintVMOptions, false,                                      \
1052           "Print flags that appeared on the command line")                  \
1053                                                                             \
1054   product(bool, IgnoreUnrecognizedVMOptions, false,                         \
1055           "Ignore unrecognized VM options")                                 \
1056                                                                             \
1057   product(bool, PrintCommandLineFlags, false,                               \
1058           "Print flags specified on command line or set by ergonomics")     \
1059                                                                             \
1060   product(bool, PrintFlagsInitial, false,                                   \
1061           "Print all VM flags before argument processing and exit VM")      \
1062                                                                             \
1063   product(bool, PrintFlagsFinal, false,                                     \
1064           "Print all VM flags after argument and ergonomic processing")     \
1065                                                                             \
1066   notproduct(bool, PrintFlagsWithComments, false,                           \
1067           "Print all VM flags with default values and descriptions and "    \
1068           "exit")                                                           \
1069                                                                             \
1070   product(bool, PrintFlagsRanges, false,                                    \
1071           "Print VM flags and their ranges")                                \
1072                                                                             \
1073   product(bool, SerializeVMOutput, true, DIAGNOSTIC,                        \
1074           "Use a mutex to serialize output to tty and LogFile")             \
1075                                                                             \
1076   product(bool, DisplayVMOutput, true, DIAGNOSTIC,                          \
1077           "Display all VM output on the tty, independently of LogVMOutput") \
1078                                                                             \
1079   product(bool, LogVMOutput, false, DIAGNOSTIC,                             \
1080           "Save VM output to LogFile")                                      \
1081                                                                             \
1082   product(ccstr, LogFile, NULL, DIAGNOSTIC,                                 \
1083           "If LogVMOutput or LogCompilation is on, save VM output to "      \
1084           "this file [default: ./hotspot_pid%p.log] (%p replaced with pid)")\
1085                                                                             \
1086   product(ccstr, ErrorFile, NULL,                                           \
1087           "If an error occurs, save the error data to this file "           \
1088           "[default: ./hs_err_pid%p.log] (%p replaced with pid)")           \
1089                                                                             \
1090   product(bool, ExtensiveErrorReports,                                      \
1091           PRODUCT_ONLY(false) NOT_PRODUCT(true),                            \
1092           "Error reports are more extensive.")                              \
1093                                                                             \
1094   product(bool, DisplayVMOutputToStderr, false,                             \
1095           "If DisplayVMOutput is true, display all VM output to stderr")    \
1096                                                                             \
1097   product(bool, DisplayVMOutputToStdout, false,                             \
1098           "If DisplayVMOutput is true, display all VM output to stdout")    \
1099                                                                             \
1100   product(bool, ErrorFileToStderr, false,                                   \
1101           "If true, error data is printed to stderr instead of a file")     \
1102                                                                             \
1103   product(bool, ErrorFileToStdout, false,                                   \
1104           "If true, error data is printed to stdout instead of a file")     \
1105                                                                             \
1106   product(bool, UseHeavyMonitors, false,                                    \
1107           "use heavyweight instead of lightweight Java monitors")           \
1108                                                                             \
1109   product(bool, PrintStringTableStatistics, false,                          \
1110           "print statistics about the StringTable and SymbolTable")         \
1111                                                                             \
1112   product(bool, VerifyStringTableAtExit, false, DIAGNOSTIC,                 \
1113           "verify StringTable contents at exit")                            \
1114                                                                             \
1115   notproduct(bool, PrintSymbolTableSizeHistogram, false,                    \
1116           "print histogram of the symbol table")                            \
1117                                                                             \
1118   product(ccstr, AbortVMOnException, NULL, DIAGNOSTIC,                      \
1119           "Call fatal if this exception is thrown.  Example: "              \
1120           "java -XX:AbortVMOnException=java.lang.NullPointerException Foo") \
1121                                                                             \
1122   product(ccstr, AbortVMOnExceptionMessage, NULL, DIAGNOSTIC,               \
1123           "Call fatal if the exception pointed by AbortVMOnException "      \
1124           "has this message")                                               \
1125                                                                             \
1126   develop(bool, DebugVtables, false,                                        \
1127           "add debugging code to vtable dispatch")                          \
1128                                                                             \
1129   notproduct(bool, PrintVtableStats, false,                                 \
1130           "print vtables stats at end of run")                              \
1131                                                                             \
1132   develop(bool, TraceCreateZombies, false,                                  \
1133           "trace creation of zombie nmethods")                              \
1134                                                                             \
1135   product(bool, RangeCheckElimination, true,                                \
1136           "Eliminate range checks")                                         \
1137                                                                             \
1138   develop_pd(bool, UncommonNullCast,                                        \
1139           "track occurrences of null in casts; adjust compiler tactics")    \
1140                                                                             \
1141   develop(bool, TypeProfileCasts,  true,                                    \
1142           "treat casts like calls for purposes of type profiling")          \
1143                                                                             \
1144   develop(bool, TraceLivenessGen, false,                                    \
1145           "Trace the generation of liveness analysis information")          \
1146                                                                             \
1147   notproduct(bool, TraceLivenessQuery, false,                               \
1148           "Trace queries of liveness analysis information")                 \
1149                                                                             \
1150   notproduct(bool, CollectIndexSetStatistics, false,                        \
1151           "Collect information about IndexSets")                            \
1152                                                                             \
1153   develop(intx, FastAllocateSizeLimit, 128*K,                               \
1154           /* Note:  This value is zero mod 1<<13 for a cheap sparc set. */  \
1155           "Inline allocations larger than this in doublewords must go slow")\
1156                                                                             \
1157   product_pd(bool, CompactStrings,                                          \
1158           "Enable Strings to use single byte chars in backing store")       \
1159                                                                             \
1160   product_pd(uintx, TypeProfileLevel,                                       \
1161           "=XYZ, with Z: Type profiling of arguments at call; "             \
1162                      "Y: Type profiling of return value at call; "          \
1163                      "X: Type profiling of parameters to methods; "         \
1164           "X, Y and Z in 0=off ; 1=jsr292 only; 2=all methods")             \
1165           constraint(TypeProfileLevelConstraintFunc, AfterErgo)             \
1166                                                                             \
1167   product(intx, TypeProfileArgsLimit,     2,                                \
1168           "max number of call arguments to consider for type profiling")    \
1169           range(0, 16)                                                      \
1170                                                                             \
1171   product(intx, TypeProfileParmsLimit,    2,                                \
1172           "max number of incoming parameters to consider for type profiling"\
1173           ", -1 for all")                                                   \
1174           range(-1, 64)                                                     \
1175                                                                             \
1176   /* statistics */                                                          \
1177   develop(bool, CountCompiledCalls, false,                                  \
1178           "Count method invocations")                                       \
1179                                                                             \
1180   notproduct(bool, ICMissHistogram, false,                                  \
1181           "Produce histogram of IC misses")                                 \
1182                                                                             \
1183   /* interpreter */                                                         \
1184   product_pd(bool, RewriteBytecodes,                                        \
1185           "Allow rewriting of bytecodes (bytecodes are not immutable)")     \
1186                                                                             \
1187   product_pd(bool, RewriteFrequentPairs,                                    \
1188           "Rewrite frequently used bytecode pairs into a single bytecode")  \
1189                                                                             \
1190   product(bool, PrintInterpreter, false, DIAGNOSTIC,                        \
1191           "Print the generated interpreter code")                           \
1192                                                                             \
1193   product(bool, UseInterpreter, true,                                       \
1194           "Use interpreter for non-compiled methods")                       \
1195                                                                             \
1196   develop(bool, UseFastSignatureHandlers, true,                             \
1197           "Use fast signature handlers for native calls")                   \
1198                                                                             \
1199   product(bool, UseLoopCounter, true,                                       \
1200           "Increment invocation counter on backward branch")                \
1201                                                                             \
1202   product_pd(bool, UseOnStackReplacement,                                   \
1203           "Use on stack replacement, calls runtime if invoc. counter "      \
1204           "overflows in loop")                                              \
1205                                                                             \
1206   notproduct(bool, TraceOnStackReplacement, false,                          \
1207           "Trace on stack replacement")                                     \
1208                                                                             \
1209   product_pd(bool, PreferInterpreterNativeStubs,                            \
1210           "Use always interpreter stubs for native methods invoked via "    \
1211           "interpreter")                                                    \
1212                                                                             \
1213   develop(bool, CountBytecodes, false,                                      \
1214           "Count number of bytecodes executed")                             \
1215                                                                             \
1216   develop(bool, PrintBytecodeHistogram, false,                              \
1217           "Print histogram of the executed bytecodes")                      \
1218                                                                             \
1219   develop(bool, PrintBytecodePairHistogram, false,                          \
1220           "Print histogram of the executed bytecode pairs")                 \
1221                                                                             \
1222   product(bool, PrintSignatureHandlers, false, DIAGNOSTIC,                  \
1223           "Print code generated for native method signature handlers")      \
1224                                                                             \
1225   develop(bool, VerifyOops, false,                                          \
1226           "Do plausibility checks for oops")                                \
1227                                                                             \
1228   develop(bool, CheckUnhandledOops, false,                                  \
1229           "Check for unhandled oops in VM code")                            \
1230                                                                             \
1231   develop(bool, VerifyJNIFields, trueInDebug,                               \
1232           "Verify jfieldIDs for instance fields")                           \
1233                                                                             \
1234   notproduct(bool, VerifyJNIEnvThread, false,                               \
1235           "Verify JNIEnv.thread == Thread::current() when entering VM "     \
1236           "from JNI")                                                       \
1237                                                                             \
1238   develop(bool, VerifyFPU, false,                                           \
1239           "Verify FPU state (check for NaN's, etc.)")                       \
1240                                                                             \
1241   develop(bool, VerifyThread, false,                                        \
1242           "Watch the thread register for corruption (SPARC only)")          \
1243                                                                             \
1244   develop(bool, VerifyActivationFrameSize, false,                           \
1245           "Verify that activation frame didn't become smaller than its "    \
1246           "minimal size")                                                   \
1247                                                                             \
1248   develop(bool, TraceFrequencyInlining, false,                              \
1249           "Trace frequency based inlining")                                 \
1250                                                                             \
1251   develop_pd(bool, InlineIntrinsics,                                        \
1252           "Inline intrinsics that can be statically resolved")              \
1253                                                                             \
1254   product_pd(bool, ProfileInterpreter,                                      \
1255           "Profile at the bytecode level during interpretation")            \
1256                                                                             \
1257   develop_pd(bool, ProfileTraps,                                            \
1258           "Profile deoptimization traps at the bytecode level")             \
1259                                                                             \
1260   product(intx, ProfileMaturityPercentage, 20,                              \
1261           "number of method invocations/branches (expressed as % of "       \
1262           "CompileThreshold) before using the method's profile")            \
1263           range(0, 100)                                                     \
1264                                                                             \
1265   product(bool, PrintMethodData, false, DIAGNOSTIC,                         \
1266           "Print the results of +ProfileInterpreter at end of run")         \
1267                                                                             \
1268   develop(bool, VerifyDataPointer, trueInDebug,                             \
1269           "Verify the method data pointer during interpreter profiling")    \
1270                                                                             \
1271   notproduct(bool, CrashGCForDumpingJavaThread, false,                      \
1272           "Manually make GC thread crash then dump java stack trace;  "     \
1273           "Test only")                                                      \
1274                                                                             \
1275   /* compilation */                                                         \
1276   product(bool, UseCompiler, true,                                          \
1277           "Use Just-In-Time compilation")                                   \
1278                                                                             \
1279   product(bool, UseCounterDecay, true,                                      \
1280           "Adjust recompilation counters")                                  \
1281                                                                             \
1282   develop(intx, CounterHalfLifeTime,    30,                                 \
1283           "Half-life time of invocation counters (in seconds)")             \
1284                                                                             \
1285   develop(intx, CounterDecayMinIntervalLength,   500,                       \
1286           "The minimum interval (in milliseconds) between invocation of "   \
1287           "CounterDecay")                                                   \
1288                                                                             \
1289   product(bool, AlwaysCompileLoopMethods, false,                            \
1290           "When using recompilation, never interpret methods "              \
1291           "containing loops")                                               \
1292                                                                             \
1293   product(intx,  AllocatePrefetchStyle, 1,                                  \
1294           "0 = no prefetch, "                                               \
1295           "1 = generate prefetch instructions for each allocation, "        \
1296           "2 = use TLAB watermark to gate allocation prefetch, "            \
1297           "3 = generate one prefetch instruction per cache line")           \
1298           range(0, 3)                                                       \
1299                                                                             \
1300   product(intx,  AllocatePrefetchDistance, -1,                              \
1301           "Distance to prefetch ahead of allocation pointer. "              \
1302           "-1: use system-specific value (automatically determined")        \
1303           constraint(AllocatePrefetchDistanceConstraintFunc,AfterMemoryInit)\
1304                                                                             \
1305   product(intx,  AllocatePrefetchLines, 3,                                  \
1306           "Number of lines to prefetch ahead of array allocation pointer")  \
1307           range(1, 64)                                                      \
1308                                                                             \
1309   product(intx,  AllocateInstancePrefetchLines, 1,                          \
1310           "Number of lines to prefetch ahead of instance allocation "       \
1311           "pointer")                                                        \
1312           range(1, 64)                                                      \
1313                                                                             \
1314   product(intx,  AllocatePrefetchStepSize, 16,                              \
1315           "Step size in bytes of sequential prefetch instructions")         \
1316           range(1, 512)                                                     \
1317           constraint(AllocatePrefetchStepSizeConstraintFunc,AfterMemoryInit)\
1318                                                                             \
1319   product(intx,  AllocatePrefetchInstr, 0,                                  \
1320           "Select instruction to prefetch ahead of allocation pointer")     \
1321           constraint(AllocatePrefetchInstrConstraintFunc, AfterMemoryInit)  \
1322                                                                             \
1323   /* deoptimization */                                                      \
1324   develop(bool, TraceDeoptimization, false,                                 \
1325           "Trace deoptimization")                                           \
1326                                                                             \
1327   develop(bool, PrintDeoptimizationDetails, false,                          \
1328           "Print more information about deoptimization")                    \
1329                                                                             \
1330   develop(bool, DebugDeoptimization, false,                                 \
1331           "Tracing various information while debugging deoptimization")     \
1332                                                                             \
1333   product(intx, SelfDestructTimer, 0,                                       \
1334           "Will cause VM to terminate after a given time (in minutes) "     \
1335           "(0 means off)")                                                  \
1336           range(0, max_intx)                                                \
1337                                                                             \
1338   product(intx, MaxJavaStackTraceDepth, 1024,                               \
1339           "The maximum number of lines in the stack trace for Java "        \
1340           "exceptions (0 means all)")                                       \
1341           range(0, max_jint/2)                                              \
1342                                                                             \
1343   /* notice: the max range value here is max_jint, not max_intx  */         \
1344   /* because of overflow issue                                   */         \
1345   product(intx, GuaranteedSafepointInterval, 1000, DIAGNOSTIC,              \
1346           "Guarantee a safepoint (at least) every so many milliseconds "    \
1347           "(0 means none)")                                                 \
1348           range(0, max_jint)                                                \
1349                                                                             \
1350   product(intx, SafepointTimeoutDelay, 10000,                               \
1351           "Delay in milliseconds for option SafepointTimeout")              \
1352           range(0, max_intx LP64_ONLY(/MICROUNITS))                         \
1353                                                                             \
1354   product(intx, NmethodSweepActivity, 10,                                   \
1355           "Removes cold nmethods from code cache if > 0. Higher values "    \
1356           "result in more aggressive sweeping")                             \
1357           range(0, 2000)                                                    \
1358                                                                             \
1359   notproduct(bool, LogSweeper, false,                                       \
1360           "Keep a ring buffer of sweeper activity")                         \
1361                                                                             \
1362   notproduct(intx, SweeperLogEntries, 1024,                                 \
1363           "Number of records in the ring buffer of sweeper activity")       \
1364                                                                             \
1365   develop(intx, MallocCatchPtr, -1,                                         \
1366           "Hit breakpoint when mallocing/freeing this pointer")             \
1367                                                                             \
1368   notproduct(ccstrlist, SuppressErrorAt, "",                                \
1369           "List of assertions (file:line) to muzzle")                       \
1370                                                                             \
1371   develop(intx, StackPrintLimit, 100,                                       \
1372           "number of stack frames to print in VM-level stack dump")         \
1373                                                                             \
1374   notproduct(intx, MaxElementPrintSize, 256,                                \
1375           "maximum number of elements to print")                            \
1376                                                                             \
1377   notproduct(intx, MaxSubklassPrintSize, 4,                                 \
1378           "maximum number of subklasses to print when printing klass")      \
1379                                                                             \
1380   develop(intx, MaxForceInlineLevel, 100,                                   \
1381           "maximum number of nested calls that are forced for inlining "    \
1382           "(using CompileCommand or marked w/ @ForceInline)")               \
1383           range(0, max_jint)                                                \
1384                                                                             \
1385   product(intx, MinInliningThreshold, 250,                                  \
1386           "The minimum invocation count a method needs to have to be "      \
1387           "inlined")                                                        \
1388           range(0, max_jint)                                                \
1389                                                                             \
1390   develop(intx, MethodHistogramCutoff, 100,                                 \
1391           "The cutoff value for method invocation histogram (+CountCalls)") \
1392                                                                             \
1393   develop(intx, DontYieldALotInterval,    10,                               \
1394           "Interval between which yields will be dropped (milliseconds)")   \
1395                                                                             \
1396   notproduct(intx, DeoptimizeALotInterval,     5,                           \
1397           "Number of exits until DeoptimizeALot kicks in")                  \
1398                                                                             \
1399   notproduct(intx, ZombieALotInterval,     5,                               \
1400           "Number of exits until ZombieALot kicks in")                      \
1401                                                                             \
1402   product(uintx, MallocMaxTestWords,     0, DIAGNOSTIC,                     \
1403           "If non-zero, maximum number of words that malloc/realloc can "   \
1404           "allocate (for testing only)")                                    \
1405           range(0, max_uintx)                                               \
1406                                                                             \
1407   product(intx, TypeProfileWidth, 2,                                        \
1408           "Number of receiver types to record in call/cast profile")        \
1409           range(0, 8)                                                       \
1410                                                                             \
1411   develop(intx, BciProfileWidth,      2,                                    \
1412           "Number of return bci's to record in ret profile")                \
1413                                                                             \
1414   product(intx, PerMethodRecompilationCutoff, 400,                          \
1415           "After recompiling N times, stay in the interpreter (-1=>'Inf')") \
1416           range(-1, max_intx)                                               \
1417                                                                             \
1418   product(intx, PerBytecodeRecompilationCutoff, 200,                        \
1419           "Per-BCI limit on repeated recompilation (-1=>'Inf')")            \
1420           range(-1, max_intx)                                               \
1421                                                                             \
1422   product(intx, PerMethodTrapLimit,  100,                                   \
1423           "Limit on traps (of one kind) in a method (includes inlines)")    \
1424           range(0, max_jint)                                                \
1425                                                                             \
1426   product(intx, PerMethodSpecTrapLimit,  5000, EXPERIMENTAL,                \
1427           "Limit on speculative traps (of one kind) in a method "           \
1428           "(includes inlines)")                                             \
1429           range(0, max_jint)                                                \
1430                                                                             \
1431   product(intx, PerBytecodeTrapLimit,  4,                                   \
1432           "Limit on traps (of one kind) at a particular BCI")               \
1433           range(0, max_jint)                                                \
1434                                                                             \
1435   product(intx, SpecTrapLimitExtraEntries,  3, EXPERIMENTAL,                \
1436           "Extra method data trap entries for speculation")                 \
1437                                                                             \
1438   develop(intx, InlineFrequencyRatio,    20,                                \
1439           "Ratio of call site execution to caller method invocation")       \
1440           range(0, max_jint)                                                \
1441                                                                             \
1442   product_pd(intx, InlineFrequencyCount, DIAGNOSTIC,                        \
1443           "Count of call site execution necessary to trigger frequent "     \
1444           "inlining")                                                       \
1445           range(0, max_jint)                                                \
1446                                                                             \
1447   develop(intx, InlineThrowCount,    50,                                    \
1448           "Force inlining of interpreted methods that throw this often")    \
1449           range(0, max_jint)                                                \
1450                                                                             \
1451   develop(intx, InlineThrowMaxSize,   200,                                  \
1452           "Force inlining of throwing methods smaller than this")           \
1453           range(0, max_jint)                                                \
1454                                                                             \
1455   product(size_t, MetaspaceSize, NOT_LP64(16 * M) LP64_ONLY(21 * M),        \
1456           "Initial threshold (in bytes) at which a garbage collection "     \
1457           "is done to reduce Metaspace usage")                              \
1458           constraint(MetaspaceSizeConstraintFunc,AfterErgo)                 \
1459                                                                             \
1460   product(size_t, MaxMetaspaceSize, max_uintx,                              \
1461           "Maximum size of Metaspaces (in bytes)")                          \
1462           constraint(MaxMetaspaceSizeConstraintFunc,AfterErgo)              \
1463                                                                             \
1464   product(size_t, CompressedClassSpaceSize, 1*G,                            \
1465           "Maximum size of class area in Metaspace when compressed "        \
1466           "class pointers are used")                                        \
1467           range(1*M, 3*G)                                                   \
1468                                                                             \
1469   develop(size_t, CompressedClassSpaceBaseAddress, 0,                       \
1470           "Force the class space to be allocated at this address or "       \
1471           "fails VM initialization (requires -Xshare=off.")                 \
1472                                                                             \
1473   product(ccstr, MetaspaceReclaimPolicy, "balanced",                        \
1474           "options: balanced, aggressive, none")                            \
1475                                                                             \
1476   product(bool, PrintMetaspaceStatisticsAtExit, false, DIAGNOSTIC,          \
1477           "Print metaspace statistics upon VM exit.")                       \
1478                                                                             \
1479   product(bool, MetaspaceGuardAllocations, false, DIAGNOSTIC,               \
1480           "Metapace allocations are guarded.")                              \
1481                                                                             \
1482   product(bool, MetaspaceHandleDeallocations, true, DIAGNOSTIC,             \
1483           "Switch off Metapace deallocation handling.")                     \
1484                                                                             \
1485   product(uintx, MinHeapFreeRatio, 40, MANAGEABLE,                          \
1486           "The minimum percentage of heap free after GC to avoid expansion."\
1487           " For most GCs this applies to the old generation. In G1 and"     \
1488           " ParallelGC it applies to the whole heap.")                      \
1489           range(0, 100)                                                     \
1490           constraint(MinHeapFreeRatioConstraintFunc,AfterErgo)              \
1491                                                                             \
1492   product(uintx, MaxHeapFreeRatio, 70, MANAGEABLE,                          \
1493           "The maximum percentage of heap free after GC to avoid shrinking."\
1494           " For most GCs this applies to the old generation. In G1 and"     \
1495           " ParallelGC it applies to the whole heap.")                      \
1496           range(0, 100)                                                     \
1497           constraint(MaxHeapFreeRatioConstraintFunc,AfterErgo)              \
1498                                                                             \
1499   product(bool, ShrinkHeapInSteps, true,                                    \
1500           "When disabled, informs the GC to shrink the java heap directly"  \
1501           " to the target size at the next full GC rather than requiring"   \
1502           " smaller steps during multiple full GCs.")                       \
1503                                                                             \
1504   product(intx, SoftRefLRUPolicyMSPerMB, 1000,                              \
1505           "Number of milliseconds per MB of free space in the heap")        \
1506           range(0, max_intx)                                                \
1507           constraint(SoftRefLRUPolicyMSPerMBConstraintFunc,AfterMemoryInit) \
1508                                                                             \
1509   product(size_t, MinHeapDeltaBytes, ScaleForWordSize(128*K),               \
1510           "The minimum change in heap space due to GC (in bytes)")          \
1511           range(0, max_uintx)                                               \
1512                                                                             \
1513   product(size_t, MinMetaspaceExpansion, ScaleForWordSize(256*K),           \
1514           "The minimum expansion of Metaspace (in bytes)")                  \
1515           range(0, max_uintx)                                               \
1516                                                                             \
1517   product(uintx, MaxMetaspaceFreeRatio,    70,                              \
1518           "The maximum percentage of Metaspace free after GC to avoid "     \
1519           "shrinking")                                                      \
1520           range(0, 100)                                                     \
1521           constraint(MaxMetaspaceFreeRatioConstraintFunc,AfterErgo)         \
1522                                                                             \
1523   product(uintx, MinMetaspaceFreeRatio,    40,                              \
1524           "The minimum percentage of Metaspace free after GC to avoid "     \
1525           "expansion")                                                      \
1526           range(0, 99)                                                      \
1527           constraint(MinMetaspaceFreeRatioConstraintFunc,AfterErgo)         \
1528                                                                             \
1529   product(size_t, MaxMetaspaceExpansion, ScaleForWordSize(4*M),             \
1530           "The maximum expansion of Metaspace without full GC (in bytes)")  \
1531           range(0, max_uintx)                                               \
1532                                                                             \
1533   /* stack parameters */                                                    \
1534   product_pd(intx, StackYellowPages,                                        \
1535           "Number of yellow zone (recoverable overflows) pages of size "    \
1536           "4KB. If pages are bigger yellow zone is aligned up.")            \
1537           range(MIN_STACK_YELLOW_PAGES, (DEFAULT_STACK_YELLOW_PAGES+5))     \
1538                                                                             \
1539   product_pd(intx, StackRedPages,                                           \
1540           "Number of red zone (unrecoverable overflows) pages of size "     \
1541           "4KB. If pages are bigger red zone is aligned up.")               \
1542           range(MIN_STACK_RED_PAGES, (DEFAULT_STACK_RED_PAGES+2))           \
1543                                                                             \
1544   product_pd(intx, StackReservedPages,                                      \
1545           "Number of reserved zone (reserved to annotated methods) pages"   \
1546           " of size 4KB. If pages are bigger reserved zone is aligned up.") \
1547           range(MIN_STACK_RESERVED_PAGES, (DEFAULT_STACK_RESERVED_PAGES+10))\
1548                                                                             \
1549   product(bool, RestrictReservedStack, true,                                \
1550           "Restrict @ReservedStackAccess to trusted classes")               \
1551                                                                             \
1552   /* greater stack shadow pages can't generate instruction to bang stack */ \
1553   product_pd(intx, StackShadowPages,                                        \
1554           "Number of shadow zone (for overflow checking) pages of size "    \
1555           "4KB. If pages are bigger shadow zone is aligned up. "            \
1556           "This should exceed the depth of the VM and native call stack.")  \
1557           range(MIN_STACK_SHADOW_PAGES, (DEFAULT_STACK_SHADOW_PAGES+30))    \
1558                                                                             \
1559   product_pd(intx, ThreadStackSize,                                         \
1560           "Thread Stack Size (in Kbytes)")                                  \
1561           range(0, 1 * M)                                                   \
1562                                                                             \
1563   product_pd(intx, VMThreadStackSize,                                       \
1564           "Non-Java Thread Stack Size (in Kbytes)")                         \
1565           range(0, max_intx/(1 * K))                                        \
1566                                                                             \
1567   product_pd(intx, CompilerThreadStackSize,                                 \
1568           "Compiler Thread Stack Size (in Kbytes)")                         \
1569           range(0, max_intx/(1 * K))                                        \
1570                                                                             \
1571   develop_pd(size_t, JVMInvokeMethodSlack,                                  \
1572           "Stack space (bytes) required for JVM_InvokeMethod to complete")  \
1573                                                                             \
1574   /* code cache parameters                                    */            \
1575   product_pd(uintx, CodeCacheSegmentSize, EXPERIMENTAL,                     \
1576           "Code cache segment size (in bytes) - smallest unit of "          \
1577           "allocation")                                                     \
1578           range(1, 1024)                                                    \
1579           constraint(CodeCacheSegmentSizeConstraintFunc, AfterErgo)         \
1580                                                                             \
1581   develop_pd(intx, CodeEntryAlignment,                                      \
1582           "Code entry alignment for generated code (in bytes)")             \
1583           constraint(CodeEntryAlignmentConstraintFunc, AfterErgo)           \
1584                                                                             \
1585   product_pd(intx, OptoLoopAlignment,                                       \
1586           "Align inner loops to zero relative to this modulus")             \
1587           range(1, 16)                                                      \
1588           constraint(OptoLoopAlignmentConstraintFunc, AfterErgo)            \
1589                                                                             \
1590   product_pd(uintx, InitialCodeCacheSize,                                   \
1591           "Initial code cache size (in bytes)")                             \
1592           constraint(VMPageSizeConstraintFunc, AtParse)                     \
1593                                                                             \
1594   develop_pd(uintx, CodeCacheMinimumUseSpace,                               \
1595           "Minimum code cache size (in bytes) required to start VM.")       \
1596           range(0, max_uintx)                                               \
1597                                                                             \
1598   product(bool, SegmentedCodeCache, false,                                  \
1599           "Use a segmented code cache")                                     \
1600                                                                             \
1601   product_pd(uintx, ReservedCodeCacheSize,                                  \
1602           "Reserved code cache size (in bytes) - maximum code cache size")  \
1603           constraint(VMPageSizeConstraintFunc, AtParse)                     \
1604                                                                             \
1605   product_pd(uintx, NonProfiledCodeHeapSize,                                \
1606           "Size of code heap with non-profiled methods (in bytes)")         \
1607           range(0, max_uintx)                                               \
1608                                                                             \
1609   product_pd(uintx, ProfiledCodeHeapSize,                                   \
1610           "Size of code heap with profiled methods (in bytes)")             \
1611           range(0, max_uintx)                                               \
1612                                                                             \
1613   product_pd(uintx, NonNMethodCodeHeapSize,                                 \
1614           "Size of code heap with non-nmethods (in bytes)")                 \
1615           constraint(VMPageSizeConstraintFunc, AtParse)                     \
1616                                                                             \
1617   product_pd(uintx, CodeCacheExpansionSize,                                 \
1618           "Code cache expansion size (in bytes)")                           \
1619           range(32*K, max_uintx)                                            \
1620                                                                             \
1621   product_pd(uintx, CodeCacheMinBlockLength, DIAGNOSTIC,                    \
1622           "Minimum number of segments in a code cache block")               \
1623           range(1, 100)                                                     \
1624                                                                             \
1625   notproduct(bool, ExitOnFullCodeCache, false,                              \
1626           "Exit the VM if we fill the code cache")                          \
1627                                                                             \
1628   product(bool, UseCodeCacheFlushing, true,                                 \
1629           "Remove cold/old nmethods from the code cache")                   \
1630                                                                             \
1631   product(double, SweeperThreshold, 0.5,                                    \
1632           "Threshold controlling when code cache sweeper is invoked."       \
1633           "Value is percentage of ReservedCodeCacheSize.")                  \
1634           range(0.0, 100.0)                                                 \
1635                                                                             \
1636   product(uintx, StartAggressiveSweepingAt, 10,                             \
1637           "Start aggressive sweeping if X[%] of the code cache is free."    \
1638           "Segmented code cache: X[%] of the non-profiled heap."            \
1639           "Non-segmented code cache: X[%] of the total code cache")         \
1640           range(0, 100)                                                     \
1641                                                                             \
1642   /* interpreter debugging */                                               \
1643   develop(intx, BinarySwitchThreshold, 5,                                   \
1644           "Minimal number of lookupswitch entries for rewriting to binary " \
1645           "switch")                                                         \
1646                                                                             \
1647   develop(intx, StopInterpreterAt, 0,                                       \
1648           "Stop interpreter execution at specified bytecode number")        \
1649                                                                             \
1650   develop(intx, TraceBytecodesAt, 0,                                        \
1651           "Trace bytecodes starting with specified bytecode number")        \
1652                                                                             \
1653   /* Priorities */                                                          \
1654   product_pd(bool, UseThreadPriorities,  "Use native thread priorities")    \
1655                                                                             \
1656   product(intx, ThreadPriorityPolicy, 0,                                    \
1657           "0 : Normal.                                                     "\
1658           "    VM chooses priorities that are appropriate for normal       "\
1659           "    applications.                                               "\
1660           "    On Windows applications are allowed to use higher native    "\
1661           "    priorities. However, with ThreadPriorityPolicy=0, VM will   "\
1662           "    not use the highest possible native priority,               "\
1663           "    THREAD_PRIORITY_TIME_CRITICAL, as it may interfere with     "\
1664           "    system threads. On Linux thread priorities are ignored      "\
1665           "    because the OS does not support static priority in          "\
1666           "    SCHED_OTHER scheduling class which is the only choice for   "\
1667           "    non-root, non-realtime applications.                        "\
1668           "1 : Aggressive.                                                 "\
1669           "    Java thread priorities map over to the entire range of      "\
1670           "    native thread priorities. Higher Java thread priorities map "\
1671           "    to higher native thread priorities. This policy should be   "\
1672           "    used with care, as sometimes it can cause performance       "\
1673           "    degradation in the application and/or the entire system. On "\
1674           "    Linux/BSD/macOS this policy requires root privilege or an   "\
1675           "    extended capability.")                                       \
1676           range(0, 1)                                                       \
1677                                                                             \
1678   product(bool, ThreadPriorityVerbose, false,                               \
1679           "Print priority changes")                                         \
1680                                                                             \
1681   product(intx, CompilerThreadPriority, -1,                                 \
1682           "The native priority at which compiler threads should run "       \
1683           "(-1 means no change)")                                           \
1684           range(min_jint, max_jint)                                         \
1685                                                                             \
1686   product(intx, VMThreadPriority, -1,                                       \
1687           "The native priority at which the VM thread should run "          \
1688           "(-1 means no change)")                                           \
1689           range(-1, 127)                                                    \
1690                                                                             \
1691   product(intx, JavaPriority1_To_OSPriority, -1,                            \
1692           "Map Java priorities to OS priorities")                           \
1693           range(-1, 127)                                                    \
1694                                                                             \
1695   product(intx, JavaPriority2_To_OSPriority, -1,                            \
1696           "Map Java priorities to OS priorities")                           \
1697           range(-1, 127)                                                    \
1698                                                                             \
1699   product(intx, JavaPriority3_To_OSPriority, -1,                            \
1700           "Map Java priorities to OS priorities")                           \
1701           range(-1, 127)                                                    \
1702                                                                             \
1703   product(intx, JavaPriority4_To_OSPriority, -1,                            \
1704           "Map Java priorities to OS priorities")                           \
1705           range(-1, 127)                                                    \
1706                                                                             \
1707   product(intx, JavaPriority5_To_OSPriority, -1,                            \
1708           "Map Java priorities to OS priorities")                           \
1709           range(-1, 127)                                                    \
1710                                                                             \
1711   product(intx, JavaPriority6_To_OSPriority, -1,                            \
1712           "Map Java priorities to OS priorities")                           \
1713           range(-1, 127)                                                    \
1714                                                                             \
1715   product(intx, JavaPriority7_To_OSPriority, -1,                            \
1716           "Map Java priorities to OS priorities")                           \
1717           range(-1, 127)                                                    \
1718                                                                             \
1719   product(intx, JavaPriority8_To_OSPriority, -1,                            \
1720           "Map Java priorities to OS priorities")                           \
1721           range(-1, 127)                                                    \
1722                                                                             \
1723   product(intx, JavaPriority9_To_OSPriority, -1,                            \
1724           "Map Java priorities to OS priorities")                           \
1725           range(-1, 127)                                                    \
1726                                                                             \
1727   product(intx, JavaPriority10_To_OSPriority,-1,                            \
1728           "Map Java priorities to OS priorities")                           \
1729           range(-1, 127)                                                    \
1730                                                                             \
1731   product(bool, UseCriticalJavaThreadPriority, false, EXPERIMENTAL,         \
1732           "Java thread priority 10 maps to critical scheduling priority")   \
1733                                                                             \
1734   product(bool, UseCriticalCompilerThreadPriority, false, EXPERIMENTAL,     \
1735           "Compiler thread(s) run at critical scheduling priority")         \
1736                                                                             \
1737   develop(intx, NewCodeParameter,      0,                                   \
1738           "Testing Only: Create a dedicated integer parameter before "      \
1739           "putback")                                                        \
1740                                                                             \
1741   /* new oopmap storage allocation */                                       \
1742   develop(intx, MinOopMapAllocation,     8,                                 \
1743           "Minimum number of OopMap entries in an OopMapSet")               \
1744                                                                             \
1745   /* recompilation */                                                       \
1746   product_pd(intx, CompileThreshold,                                        \
1747           "number of interpreted method invocations before (re-)compiling") \
1748           constraint(CompileThresholdConstraintFunc, AfterErgo)             \
1749                                                                             \
1750   product_pd(bool, TieredCompilation,                                       \
1751           "Enable tiered compilation")                                      \
1752                                                                             \
1753   /* Properties for Java libraries  */                                      \
1754                                                                             \
1755   product(uint64_t, MaxDirectMemorySize, 0,                                 \
1756           "Maximum total size of NIO direct-buffer allocations")            \
1757           range(0, max_jlong)                                               \
1758                                                                             \
1759   /* Flags used for temporary code during development  */                   \
1760                                                                             \
1761   product(bool, UseNewCode, false, DIAGNOSTIC,                              \
1762           "Testing Only: Use the new version while testing")                \
1763                                                                             \
1764   product(bool, UseNewCode2, false, DIAGNOSTIC,                             \
1765           "Testing Only: Use the new version while testing")                \
1766                                                                             \
1767   product(bool, UseNewCode3, false, DIAGNOSTIC,                             \
1768           "Testing Only: Use the new version while testing")                \
1769                                                                             \
1770   notproduct(bool, UseDebuggerErgo, false,                                  \
1771           "Debugging Only: Adjust the VM to be more debugger-friendly. "    \
1772           "Turns on the other UseDebuggerErgo* flags")                      \
1773                                                                             \
1774   notproduct(bool, UseDebuggerErgo1, false,                                 \
1775           "Debugging Only: Enable workarounds for debugger induced "        \
1776           "os::processor_id() >= os::processor_count() problems")           \
1777                                                                             \
1778   notproduct(bool, UseDebuggerErgo2, false,                                 \
1779           "Debugging Only: Limit the number of spawned JVM threads")        \
1780                                                                             \
1781   notproduct(bool, EnableJVMTIStackDepthAsserts, true,                      \
1782           "Enable JVMTI asserts related to stack depth checks")             \
1783                                                                             \
1784   /* flags for performance data collection */                               \
1785                                                                             \
1786   product(bool, UsePerfData, true,                                          \
1787           "Flag to disable jvmstat instrumentation for performance testing "\
1788           "and problem isolation purposes")                                 \
1789                                                                             \
1790   product(bool, PerfDataSaveToFile, false,                                  \
1791           "Save PerfData memory to hsperfdata_<pid> file on exit")          \
1792                                                                             \
1793   product(ccstr, PerfDataSaveFile, NULL,                                    \
1794           "Save PerfData memory to the specified absolute pathname. "       \
1795           "The string %p in the file name (if present) "                    \
1796           "will be replaced by pid")                                        \
1797                                                                             \
1798   product(intx, PerfDataSamplingInterval, 50,                               \
1799           "Data sampling interval (in milliseconds)")                       \
1800           range(PeriodicTask::min_interval, max_jint)                       \
1801           constraint(PerfDataSamplingIntervalFunc, AfterErgo)               \
1802                                                                             \
1803   product(bool, PerfDisableSharedMem, false,                                \
1804           "Store performance data in standard memory")                      \
1805                                                                             \
1806   product(intx, PerfDataMemorySize, 32*K,                                   \
1807           "Size of performance data memory region. Will be rounded "        \
1808           "up to a multiple of the native os page size.")                   \
1809           range(128, 32*64*K)                                               \
1810                                                                             \
1811   product(intx, PerfMaxStringConstLength, 1024,                             \
1812           "Maximum PerfStringConstant string length before truncation")     \
1813           range(32, 32*K)                                                   \
1814                                                                             \
1815   product(bool, PerfAllowAtExitRegistration, false,                         \
1816           "Allow registration of atexit() methods")                         \
1817                                                                             \
1818   product(bool, PerfBypassFileSystemCheck, false,                           \
1819           "Bypass Win32 file system criteria checks (Windows Only)")        \
1820                                                                             \
1821   product(intx, UnguardOnExecutionViolation, 0,                             \
1822           "Unguard page and retry on no-execute fault (Win32 only) "        \
1823           "0=off, 1=conservative, 2=aggressive")                            \
1824           range(0, 2)                                                       \
1825                                                                             \
1826   /* Serviceability Support */                                              \
1827                                                                             \
1828   product(bool, ManagementServer, false,                                    \
1829           "Create JMX Management Server")                                   \
1830                                                                             \
1831   product(bool, DisableAttachMechanism, false,                              \
1832           "Disable mechanism that allows tools to attach to this VM")       \
1833                                                                             \
1834   product(bool, StartAttachListener, false,                                 \
1835           "Always start Attach Listener at VM startup")                     \
1836                                                                             \
1837   product(bool, EnableDynamicAgentLoading, true,                            \
1838           "Allow tools to load agents with the attach mechanism")           \
1839                                                                             \
1840   product(bool, PrintConcurrentLocks, false, MANAGEABLE,                    \
1841           "Print java.util.concurrent locks in thread dump")                \
1842                                                                             \
1843   /* Shared spaces */                                                       \
1844                                                                             \
1845   product(bool, UseSharedSpaces, true,                                      \
1846           "Use shared spaces for metadata")                                 \
1847                                                                             \
1848   product(bool, VerifySharedSpaces, false,                                  \
1849           "Verify integrity of shared spaces")                              \
1850                                                                             \
1851   product(bool, RequireSharedSpaces, false,                                 \
1852           "Require shared spaces for metadata")                             \
1853                                                                             \
1854   product(bool, DumpSharedSpaces, false,                                    \
1855           "Special mode: JVM reads a class list, loads classes, builds "    \
1856           "shared spaces, and dumps the shared spaces to a file to be "     \
1857           "used in future JVM runs")                                        \
1858                                                                             \
1859   product(bool, DynamicDumpSharedSpaces, false,                             \
1860           "Dynamic archive")                                                \
1861                                                                             \
1862   product(bool, RecordDynamicDumpInfo, false,                               \
1863           "Record class info for jcmd VM.cds dynamic_dump")                 \
1864                                                                             \
1865   product(bool, PrintSharedArchiveAndExit, false,                           \
1866           "Print shared archive file contents")                             \
1867                                                                             \
1868   product(bool, PrintSharedDictionary, false,                               \
1869           "If PrintSharedArchiveAndExit is true, also print the shared "    \
1870           "dictionary")                                                     \
1871                                                                             \
1872   product(size_t, SharedBaseAddress, LP64_ONLY(32*G)                        \
1873           NOT_LP64(LINUX_ONLY(2*G) NOT_LINUX(0)),                           \
1874           "Address to allocate shared memory region for class data")        \
1875           range(0, SIZE_MAX)                                                \
1876                                                                             \
1877   product(ccstr, SharedArchiveConfigFile, NULL,                             \
1878           "Data to add to the CDS archive file")                            \
1879                                                                             \
1880   product(uintx, SharedSymbolTableBucketSize, 4,                            \
1881           "Average number of symbols per bucket in shared table")           \
1882           range(2, 246)                                                     \
1883                                                                             \
1884   product(bool, AllowArchivingWithJavaAgent, false, DIAGNOSTIC,             \
1885           "Allow Java agent to be run with CDS dumping")                    \
1886                                                                             \
1887   product(bool, PrintMethodHandleStubs, false, DIAGNOSTIC,                  \
1888           "Print generated stub code for method handles")                   \
1889                                                                             \
1890   product(bool, VerifyMethodHandles, trueInDebug, DIAGNOSTIC,               \
1891           "perform extra checks when constructing method handles")          \
1892                                                                             \
1893   product(bool, ShowHiddenFrames, false, DIAGNOSTIC,                        \
1894           "show method handle implementation frames (usually hidden)")      \
1895                                                                             \
1896   product(bool, TrustFinalNonStaticFields, false, EXPERIMENTAL,             \
1897           "trust final non-static declarations for constant folding")       \
1898                                                                             \
1899   product(bool, FoldStableValues, true, DIAGNOSTIC,                         \
1900           "Optimize loads from stable fields (marked w/ @Stable)")          \
1901                                                                             \
1902   product(int, UseBootstrapCallInfo, 1, DIAGNOSTIC,                         \
1903           "0: when resolving InDy or ConDy, force all BSM arguments to be " \
1904           "resolved before the bootstrap method is called; 1: when a BSM "  \
1905           "that may accept a BootstrapCallInfo is detected, use that API "  \
1906           "to pass BSM arguments, which allows the BSM to delay their "     \
1907           "resolution; 2+: stress test the BCI API by calling more BSMs "   \
1908           "via that API, instead of with the eagerly-resolved array.")      \
1909                                                                             \
1910   product(bool, PauseAtStartup,      false, DIAGNOSTIC,                     \
1911           "Causes the VM to pause at startup time and wait for the pause "  \
1912           "file to be removed (default: ./vm.paused.<pid>)")                \
1913                                                                             \
1914   product(ccstr, PauseAtStartupFile, NULL, DIAGNOSTIC,                      \
1915           "The file to create and for whose removal to await when pausing " \
1916           "at startup. (default: ./vm.paused.<pid>)")                       \
1917                                                                             \
1918   product(bool, PauseAtExit, false, DIAGNOSTIC,                             \
1919           "Pause and wait for keypress on exit if a debugger is attached")  \
1920                                                                             \
1921   product(bool, ExtendedDTraceProbes,    false,                             \
1922           "Enable performance-impacting dtrace probes")                     \
1923                                                                             \
1924   product(bool, DTraceMethodProbes, false,                                  \
1925           "Enable dtrace probes for method-entry and method-exit")          \
1926                                                                             \
1927   product(bool, DTraceAllocProbes, false,                                   \
1928           "Enable dtrace probes for object allocation")                     \
1929                                                                             \
1930   product(bool, DTraceMonitorProbes, false,                                 \
1931           "Enable dtrace probes for monitor events")                        \
1932                                                                             \
1933   product(bool, RelaxAccessControlCheck, false,                             \
1934           "Relax the access control checks in the verifier")                \
1935                                                                             \
1936   product(uintx, StringTableSize, defaultStringTableSize,                   \
1937           "Number of buckets in the interned String table "                 \
1938           "(will be rounded to nearest higher power of 2)")                 \
1939           range(minimumStringTableSize, 16777216ul /* 2^24 */)              \
1940                                                                             \
1941   product(uintx, SymbolTableSize, defaultSymbolTableSize, EXPERIMENTAL,     \
1942           "Number of buckets in the JVM internal Symbol table")             \
1943           range(minimumSymbolTableSize, 16777216ul /* 2^24 */)              \
1944                                                                             \
1945   product(bool, UseStringDeduplication, false,                              \
1946           "Use string deduplication")                                       \
1947                                                                             \
1948   product(uint, StringDeduplicationAgeThreshold, 3,                         \
1949           "A string must reach this age (or be promoted to an old region) " \
1950           "to be considered for deduplication")                             \
1951           range(1, markWord::max_age)                                       \
1952                                                                             \
1953   product(size_t, StringDeduplicationInitialTableSize, 500, EXPERIMENTAL,   \
1954           "Approximate initial number of buckets in the table")             \
1955           range(1, 1 * G)                                                   \
1956                                                                             \
1957   product(double, StringDeduplicationGrowTableLoad, 14.0, EXPERIMENTAL,     \
1958           "Entries per bucket above which the table should be expanded")    \
1959           range(0.1, 1000.0)                                                \
1960                                                                             \
1961   product(double, StringDeduplicationShrinkTableLoad, 1.0, EXPERIMENTAL,    \
1962           "Entries per bucket below which the table should be shrunk")      \
1963           range(0.01, 100.0)                                                \
1964                                                                             \
1965   product(double, StringDeduplicationTargetTableLoad, 7.0, EXPERIMENTAL,    \
1966           "Desired entries per bucket when resizing the table")             \
1967           range(0.01, 1000.0)                                               \
1968                                                                             \
1969   product(size_t, StringDeduplicationCleanupDeadMinimum, 100, EXPERIMENTAL, \
1970           "Minimum number of dead table entries for cleaning the table")    \
1971                                                                             \
1972   product(int, StringDeduplicationCleanupDeadPercent, 5, EXPERIMENTAL,      \
1973           "Minimum percentage of dead table entries for cleaning the table") \
1974           range(1, 100)                                                     \
1975                                                                             \
1976   product(bool, StringDeduplicationResizeALot, false, DIAGNOSTIC,           \
1977           "Force more frequent table resizing")                             \
1978                                                                             \
1979   product(uint64_t, StringDeduplicationHashSeed, 0, DIAGNOSTIC,             \
1980           "Seed for the table hashing function; 0 requests computed seed")  \
1981                                                                             \
1982   product(bool, WhiteBoxAPI, false, DIAGNOSTIC,                             \
1983           "Enable internal testing APIs")                                   \
1984                                                                             \
1985   product(ccstr, DumpLoadedClassList, NULL,                                 \
1986           "Dump the names all loaded classes, that could be stored into "   \
1987           "the CDS archive, in the specified file")                         \
1988                                                                             \
1989   product(ccstr, SharedClassListFile, NULL,                                 \
1990           "Override the default CDS class list")                            \
1991                                                                             \
1992   product(ccstr, SharedArchiveFile, NULL,                                   \
1993           "Override the default location of the CDS archive file")          \
1994                                                                             \
1995   product(ccstr, ArchiveClassesAtExit, NULL,                                \
1996           "The path and name of the dynamic archive file")                  \
1997                                                                             \
1998   product(ccstr, ExtraSharedClassListFile, NULL,                            \
1999           "Extra classlist for building the CDS archive file")              \
2000                                                                             \
2001   product(intx, ArchiveRelocationMode, 0, DIAGNOSTIC,                       \
2002            "(0) first map at preferred address, and if "                    \
2003            "unsuccessful, map at alternative address (default); "           \
2004            "(1) always map at alternative address; "                        \
2005            "(2) always map at preferred address, and if unsuccessful, "     \
2006            "do not map the archive")                                        \
2007            range(0, 2)                                                      \
2008                                                                             \
2009   product(size_t, ArrayAllocatorMallocLimit, (size_t)-1, EXPERIMENTAL,      \
2010           "Allocation less than this value will be allocated "              \
2011           "using malloc. Larger allocations will use mmap.")                \
2012                                                                             \
2013   product(bool, AlwaysAtomicAccesses, false, EXPERIMENTAL,                  \
2014           "Accesses to all variables should always be atomic")              \
2015                                                                             \
2016   product(bool, UseUnalignedAccesses, false, DIAGNOSTIC,                    \
2017           "Use unaligned memory accesses in Unsafe")                        \
2018                                                                             \
2019   product_pd(bool, PreserveFramePointer,                                    \
2020              "Use the FP register for holding the frame pointer "           \
2021              "and not as a general purpose register.")                      \
2022                                                                             \
2023   product(size_t, AsyncLogBufferSize, 2*M,                                  \
2024           "Memory budget (in bytes) for the buffer of Asynchronous "        \
2025           "Logging (-Xlog:async).")                                         \
2026           range(100*K, 50*M)                                                \
2027                                                                             \
2028   product(bool, CheckIntrinsics, true, DIAGNOSTIC,                          \
2029              "When a class C is loaded, check that "                        \
2030              "(1) all intrinsics defined by the VM for class C are present "\
2031              "in the loaded class file and are marked with the "            \
2032              "@IntrinsicCandidate annotation, that "                        \
2033              "(2) there is an intrinsic registered for all loaded methods " \
2034              "that are annotated with the @IntrinsicCandidate annotation, " \
2035              "and that "                                                    \
2036              "(3) no orphan methods exist for class C (i.e., methods for "  \
2037              "which the VM declares an intrinsic but that are not declared "\
2038              "in the loaded class C. "                                      \
2039              "Check (3) is available only in debug builds.")                \
2040                                                                             \
2041   product_pd(intx, InitArrayShortSize, DIAGNOSTIC,                          \
2042           "Threshold small size (in bytes) for clearing arrays. "           \
2043           "Anything this size or smaller may get converted to discrete "    \
2044           "scalar stores.")                                                 \
2045           range(0, max_intx)                                                \
2046           constraint(InitArrayShortSizeConstraintFunc, AfterErgo)           \
2047                                                                             \
2048   product(ccstr, AllocateHeapAt, NULL,                                      \
2049           "Path to the directory where a temporary file will be created "   \
2050           "to use as the backing store for Java Heap.")                     \
2051                                                                             \
2052   develop(int, VerifyMetaspaceInterval, DEBUG_ONLY(500) NOT_DEBUG(0),       \
2053                "Run periodic metaspace verifications (0 - none, "           \
2054                "1 - always, >1 every nth interval)")                        \
2055                                                                             \
2056   product(bool, ShowRegistersOnAssert, true, DIAGNOSTIC,                    \
2057           "On internal errors, include registers in error report.")         \
2058                                                                             \
2059   product(bool, UseSwitchProfiling, true, DIAGNOSTIC,                       \
2060           "leverage profiling for table/lookup switch")                     \
2061                                                                             \
2062   develop(bool, TraceMemoryWriteback, false,                                \
2063           "Trace memory writeback operations")                              \
2064                                                                             \
2065   JFR_ONLY(product(bool, FlightRecorder, false,                             \
2066           "(Deprecated) Enable Flight Recorder"))                           \
2067                                                                             \
2068   JFR_ONLY(product(ccstr, FlightRecorderOptions, NULL,                      \
2069           "Flight Recorder options"))                                       \
2070                                                                             \
2071   JFR_ONLY(product(ccstr, StartFlightRecording, NULL,                       \
2072           "Start flight recording with options"))                           \
2073                                                                             \
2074   product(bool, UseFastUnorderedTimeStamps, false, EXPERIMENTAL,            \
2075           "Use platform unstable time where supported for timestamps only") \
2076                                                                             \
2077   product(bool, UseEmptySlotsInSupers, true,                                \
2078                 "Allow allocating fields in empty slots of super-classes")  \
2079                                                                             \
2080   product(bool, DeoptimizeNMethodBarriersALot, false, DIAGNOSTIC,           \
2081                 "Make nmethod barriers deoptimise a lot.")                  \
2082                                                                             \
2083   develop(bool, VerifyCrossModifyFence,                                     \
2084           false AARCH64_ONLY(DEBUG_ONLY(||true)),                           \
2085              "Mark all threads after a safepoint, and clear on a modify "   \
2086              "fence. Add cleanliness checks.")                              \
2087                                                                             \
2088   develop(bool, TraceOptimizedUpcallStubs, false,                              \
2089                 "Trace optimized upcall stub generation")                      \
2090 
2091 // end of RUNTIME_FLAGS
2092 
2093 DECLARE_FLAGS(LP64_RUNTIME_FLAGS)
2094 DECLARE_ARCH_FLAGS(ARCH_FLAGS)
2095 DECLARE_FLAGS(RUNTIME_FLAGS)
2096 DECLARE_FLAGS(RUNTIME_OS_FLAGS)
2097 
2098 #endif // SHARE_RUNTIME_GLOBALS_HPP