1 /*
   2  * Copyright (c) 1997, 2024, 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 may not be
  71 //    an officially supported part of a product, but may be 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 //    Refer to the documentation of any products using this code for details
  79 //    on support and fitness for production.
  80 //    Like the UnlockDiagnosticVMOptions flag above, there is a corresponding
  81 //    UnlockExperimentalVMOptions flag, which allows the control and
  82 //    modification of the experimental flags.
  83 //
  84 // Nota bene: neither diagnostic nor experimental options should be used casually,
  85 //    Refer to the documentation of any products using this code for details.
  86 //
  87 // MANAGEABLE flags are writeable external product flags.
  88 //    They are dynamically writeable through the JDK management interface
  89 //    (com.sun.management.HotSpotDiagnosticMXBean API) and also through JConsole.
  90 //    These flags are external exported interface (see CSR).  The list of
  91 //    manageable flags can be queried programmatically through the management
  92 //    interface.
  93 //
  94 //    A flag can be made as "manageable" only if
  95 //    - the flag is defined in a CSR request as an external exported interface.
  96 //    - the VM implementation supports dynamic setting of the flag.
  97 //      This implies that the VM must *always* query the flag variable
  98 //      and not reuse state related to the flag state at any given time.
  99 //    - you want the flag to be queried programmatically by the customers.
 100 //
 101 
 102 //
 103 // range is a macro that will expand to min and max arguments for range
 104 //    checking code if provided - see jvmFlagLimit.hpp
 105 //
 106 // constraint is a macro that will expand to custom function call
 107 //    for constraint checking if provided - see jvmFlagLimit.hpp
 108 
 109 // Default and minimum StringTable and SymbolTable size values
 110 // Must be powers of 2
 111 const size_t defaultStringTableSize = NOT_LP64(1024) LP64_ONLY(65536);
 112 const size_t minimumStringTableSize = 128;
 113 const size_t defaultSymbolTableSize = 32768; // 2^15
 114 const size_t minimumSymbolTableSize = 1024;
 115 
 116 #ifdef _LP64
 117 #define LP64_RUNTIME_FLAGS(develop,                                         \
 118                            develop_pd,                                      \
 119                            product,                                         \
 120                            product_pd,                                      \
 121                            notproduct,                                      \
 122                            range,                                           \
 123                            constraint)                                      \
 124                                                                             \
 125   product(bool, UseCompressedOops, false,                                   \
 126           "Use 32-bit object references in 64-bit VM. "                     \
 127           "lp64_product means flag is always constant in 32 bit VM")        \
 128                                                                             \
 129   product(bool, UseCompressedClassPointers, true,                           \
 130           "Use 32-bit class pointers in 64-bit VM. "                        \
 131           "lp64_product means flag is always constant in 32 bit VM")        \
 132                                                                             \
 133   product(bool, UseCompactObjectHeaders, false, EXPERIMENTAL,               \
 134           "Use compact 64-bit object headers in 64-bit VM")                 \
 135                                                                             \
 136   product(int, ObjectAlignmentInBytes, 8,                                   \
 137           "Default object alignment in bytes, 8 is minimum")                \
 138           range(8, 256)                                                     \
 139           constraint(ObjectAlignmentInBytesConstraintFunc, AtParse)
 140 
 141 #else
 142 // !_LP64
 143 
 144 #define LP64_RUNTIME_FLAGS(develop,                                         \
 145                            develop_pd,                                      \
 146                            product,                                         \
 147                            product_pd,                                      \
 148                            notproduct,                                      \
 149                            range,                                           \
 150                            constraint)
 151 const bool UseCompressedOops = false;
 152 const bool UseCompressedClassPointers = false;
 153 const bool UseCompactObjectHeaders = false;
 154 const int ObjectAlignmentInBytes = 8;
 155 
 156 #endif // _LP64
 157 
 158 #define RUNTIME_FLAGS(develop,                                              \
 159                       develop_pd,                                           \
 160                       product,                                              \
 161                       product_pd,                                           \
 162                       notproduct,                                           \
 163                       range,                                                \
 164                       constraint)                                           \
 165                                                                             \
 166   notproduct(bool, CheckCompressedOops, true,                               \
 167           "Generate checks in encoding/decoding code in debug VM")          \
 168                                                                             \
 169   product(uintx, HeapSearchSteps, 3 PPC64_ONLY(+17),                        \
 170           "Heap allocation steps through preferred address regions to find" \
 171           " where it can allocate the heap. Number of steps to take per "   \
 172           "region.")                                                        \
 173           range(1, max_uintx)                                               \
 174                                                                             \
 175   product(uint, HandshakeTimeout, 0, DIAGNOSTIC,                            \
 176           "If nonzero set a timeout in milliseconds for handshakes")        \
 177                                                                             \
 178   product(bool, AlwaysSafeConstructors, false, EXPERIMENTAL,                \
 179           "Force safe construction, as if all fields are final.")           \
 180                                                                             \
 181   product(bool, UnlockDiagnosticVMOptions, trueInDebug, DIAGNOSTIC,         \
 182           "Enable normal processing of flags relating to field diagnostics")\
 183                                                                             \
 184   product(bool, UnlockExperimentalVMOptions, false, EXPERIMENTAL,           \
 185           "Enable normal processing of flags relating to experimental "     \
 186           "features")                                                       \
 187                                                                             \
 188   product(bool, JavaMonitorsInStackTrace, true,                             \
 189           "Print information about Java monitor locks when the stacks are " \
 190           "dumped")                                                         \
 191                                                                             \
 192   product_pd(bool, UseLargePages,                                           \
 193           "Use large page memory")                                          \
 194                                                                             \
 195   product_pd(bool, UseLargePagesIndividualAllocation,                       \
 196           "Allocate large pages individually for better affinity")          \
 197                                                                             \
 198   develop(bool, LargePagesIndividualAllocationInjectError, false,           \
 199           "Fail large pages individual allocation")                         \
 200                                                                             \
 201   product(bool, UseNUMA, false,                                             \
 202           "Use NUMA if available")                                          \
 203                                                                             \
 204   product(bool, UseNUMAInterleaving, false,                                 \
 205           "Interleave memory across NUMA nodes if available")               \
 206                                                                             \
 207   product(size_t, NUMAInterleaveGranularity, 2*M,                           \
 208           "Granularity to use for NUMA interleaving on Windows OS")         \
 209           constraint(NUMAInterleaveGranularityConstraintFunc, AtParse)      \
 210                                                                             \
 211   product(uintx, NUMAChunkResizeWeight, 20,                                 \
 212           "Percentage (0-100) used to weight the current sample when "      \
 213           "computing exponentially decaying average for "                   \
 214           "AdaptiveNUMAChunkSizing")                                        \
 215           range(0, 100)                                                     \
 216                                                                             \
 217   product(size_t, NUMASpaceResizeRate, 1*G,                                 \
 218           "Do not reallocate more than this amount per collection")         \
 219           range(0, max_uintx)                                               \
 220                                                                             \
 221   product(bool, UseAdaptiveNUMAChunkSizing, true,                           \
 222           "Enable adaptive chunk sizing for NUMA")                          \
 223                                                                             \
 224   product(bool, NUMAStats, false,                                           \
 225           "Print NUMA stats in detailed heap information")                  \
 226                                                                             \
 227   product(uintx, NUMAPageScanRate, 256,                                     \
 228           "Maximum number of pages to include in the page scan procedure")  \
 229           range(0, max_uintx)                                               \
 230                                                                             \
 231   product(bool, UseAES, false,                                              \
 232           "Control whether AES instructions are used when available")       \
 233                                                                             \
 234   product(bool, UseFMA, false,                                              \
 235           "Control whether FMA instructions are used when available")       \
 236                                                                             \
 237   product(bool, UseSHA, false,                                              \
 238           "Control whether SHA instructions are used when available")       \
 239                                                                             \
 240   product(bool, UseGHASHIntrinsics, false, DIAGNOSTIC,                      \
 241           "Use intrinsics for GHASH versions of crypto")                    \
 242                                                                             \
 243   product(bool, UseBASE64Intrinsics, false,                                 \
 244           "Use intrinsics for java.util.Base64")                            \
 245                                                                             \
 246   product(bool, UsePoly1305Intrinsics, false, DIAGNOSTIC,                   \
 247           "Use intrinsics for sun.security.util.math.intpoly")              \
 248                                                                             \
 249   product(size_t, LargePageSizeInBytes, 0,                                  \
 250           "Maximum large page size used (0 will use the default large "     \
 251           "page size for the environment as the maximum)")                  \
 252           range(0, max_uintx)                                               \
 253                                                                             \
 254   product(size_t, LargePageHeapSizeThreshold, 128*M,                        \
 255           "Use large pages if maximum heap is at least this big")           \
 256           range(0, max_uintx)                                               \
 257                                                                             \
 258   product(bool, ForceTimeHighResolution, false,                             \
 259           "Using high time resolution (for Win32 only)")                    \
 260                                                                             \
 261   develop(bool, TracePcPatching, false,                                     \
 262           "Trace usage of frame::patch_pc")                                 \
 263                                                                             \
 264   develop(bool, TraceRelocator, false,                                      \
 265           "Trace the bytecode relocator")                                   \
 266                                                                             \
 267                                                                             \
 268   product(bool, SafepointALot, false, DIAGNOSTIC,                           \
 269           "Generate a lot of safepoints. This works with "                  \
 270           "GuaranteedSafepointInterval")                                    \
 271                                                                             \
 272   product(bool, HandshakeALot, false, DIAGNOSTIC,                           \
 273           "Generate a lot of handshakes. This works with "                  \
 274           "GuaranteedSafepointInterval")                                    \
 275                                                                             \
 276   product_pd(bool, BackgroundCompilation,                                   \
 277           "A thread requesting compilation is not blocked during "          \
 278           "compilation")                                                    \
 279                                                                             \
 280   product(bool, MethodFlushing, true,                                       \
 281           "Reclamation of compiled methods")                                \
 282                                                                             \
 283   develop(bool, VerifyStack, false,                                         \
 284           "Verify stack of each thread when it is entering a runtime call") \
 285                                                                             \
 286   product(bool, ForceUnreachable, false, DIAGNOSTIC,                        \
 287           "Make all non code cache addresses to be unreachable by "         \
 288           "forcing use of 64bit literal fixups")                            \
 289                                                                             \
 290   develop(bool, TraceDerivedPointers, false,                                \
 291           "Trace traversal of derived pointers on stack")                   \
 292                                                                             \
 293   notproduct(bool, TraceCodeBlobStacks, false,                              \
 294           "Trace stack-walk of codeblobs")                                  \
 295                                                                             \
 296   notproduct(bool, PrintRewrites, false,                                    \
 297           "Print methods that are being rewritten")                         \
 298                                                                             \
 299   product(bool, UseInlineCaches, true,                                      \
 300           "Use Inline Caches for virtual calls ")                           \
 301                                                                             \
 302   product(size_t, InlineCacheBufferSize, 10*K, EXPERIMENTAL,                \
 303           "InlineCacheBuffer size")                                         \
 304                                                                             \
 305   product(bool, InlineArrayCopy, true, DIAGNOSTIC,                          \
 306           "Inline arraycopy native that is known to be part of "            \
 307           "base library DLL")                                               \
 308                                                                             \
 309   product(bool, InlineObjectHash, true, DIAGNOSTIC,                         \
 310           "Inline Object::hashCode() native that is known to be part "      \
 311           "of base library DLL")                                            \
 312                                                                             \
 313   product(bool, InlineNatives, true, DIAGNOSTIC,                            \
 314           "Inline natives that are known to be part of base library DLL")   \
 315                                                                             \
 316   product(bool, InlineMathNatives, true, DIAGNOSTIC,                        \
 317           "Inline SinD, CosD, etc.")                                        \
 318                                                                             \
 319   product(bool, InlineClassNatives, true, DIAGNOSTIC,                       \
 320           "Inline Class.isInstance, etc")                                   \
 321                                                                             \
 322   product(bool, InlineThreadNatives, true, DIAGNOSTIC,                      \
 323           "Inline Thread.currentThread, etc")                               \
 324                                                                             \
 325   product(bool, InlineUnsafeOps, true, DIAGNOSTIC,                          \
 326           "Inline memory ops (native methods) from Unsafe")                 \
 327                                                                             \
 328   product(bool, UseAESIntrinsics, false, DIAGNOSTIC,                        \
 329           "Use intrinsics for AES versions of crypto")                      \
 330                                                                             \
 331   product(bool, UseAESCTRIntrinsics, false, DIAGNOSTIC,                     \
 332           "Use intrinsics for the paralleled version of AES/CTR crypto")    \
 333                                                                             \
 334   product(bool, UseChaCha20Intrinsics, false, DIAGNOSTIC,                   \
 335           "Use intrinsics for the vectorized version of ChaCha20")          \
 336                                                                             \
 337   product(bool, UseMD5Intrinsics, false, DIAGNOSTIC,                        \
 338           "Use intrinsics for MD5 crypto hash function")                    \
 339                                                                             \
 340   product(bool, UseSHA1Intrinsics, false, DIAGNOSTIC,                       \
 341           "Use intrinsics for SHA-1 crypto hash function. "                 \
 342           "Requires that UseSHA is enabled.")                               \
 343                                                                             \
 344   product(bool, UseSHA256Intrinsics, false, DIAGNOSTIC,                     \
 345           "Use intrinsics for SHA-224 and SHA-256 crypto hash functions. "  \
 346           "Requires that UseSHA is enabled.")                               \
 347                                                                             \
 348   product(bool, UseSHA512Intrinsics, false, DIAGNOSTIC,                     \
 349           "Use intrinsics for SHA-384 and SHA-512 crypto hash functions. "  \
 350           "Requires that UseSHA is enabled.")                               \
 351                                                                             \
 352   product(bool, UseSHA3Intrinsics, false, DIAGNOSTIC,                       \
 353           "Use intrinsics for SHA3 crypto hash function. "                  \
 354           "Requires that UseSHA is enabled.")                               \
 355                                                                             \
 356   product(bool, UseCRC32Intrinsics, false, DIAGNOSTIC,                      \
 357           "use intrinsics for java.util.zip.CRC32")                         \
 358                                                                             \
 359   product(bool, UseCRC32CIntrinsics, false, DIAGNOSTIC,                     \
 360           "use intrinsics for java.util.zip.CRC32C")                        \
 361                                                                             \
 362   product(bool, UseAdler32Intrinsics, false, DIAGNOSTIC,                    \
 363           "use intrinsics for java.util.zip.Adler32")                       \
 364                                                                             \
 365   product(bool, UseVectorizedMismatchIntrinsic, false, DIAGNOSTIC,          \
 366           "Enables intrinsification of ArraysSupport.vectorizedMismatch()") \
 367                                                                             \
 368   product(bool, UseVectorizedHashCodeIntrinsic, false, DIAGNOSTIC,          \
 369           "Enables intrinsification of ArraysSupport.vectorizedHashCode()") \
 370                                                                             \
 371   product(bool, UseCopySignIntrinsic, false, DIAGNOSTIC,                    \
 372           "Enables intrinsification of Math.copySign")                      \
 373                                                                             \
 374   product(bool, UseSignumIntrinsic, false, DIAGNOSTIC,                      \
 375           "Enables intrinsification of Math.signum")                        \
 376                                                                             \
 377   product_pd(bool, DelayCompilerStubsGeneration, DIAGNOSTIC,                \
 378           "Use Compiler thread for compiler's stubs generation")            \
 379                                                                             \
 380   product(ccstrlist, DisableIntrinsic, "", DIAGNOSTIC,                      \
 381          "do not expand intrinsics whose (internal) names appear here")     \
 382          constraint(DisableIntrinsicConstraintFunc,AfterErgo)               \
 383                                                                             \
 384   product(ccstrlist, ControlIntrinsic, "", DIAGNOSTIC,                      \
 385          "Control intrinsics using a list of +/- (internal) names, "        \
 386          "separated by commas")                                             \
 387          constraint(ControlIntrinsicConstraintFunc,AfterErgo)               \
 388                                                                             \
 389   develop(bool, TraceCallFixup, false,                                      \
 390           "Trace all call fixups")                                          \
 391                                                                             \
 392   develop(bool, DeoptimizeALot, false,                                      \
 393           "Deoptimize at every exit from the runtime system")               \
 394                                                                             \
 395   notproduct(ccstrlist, DeoptimizeOnlyAt, "",                               \
 396           "A comma separated list of bcis to deoptimize at")                \
 397                                                                             \
 398   develop(bool, DeoptimizeRandom, false,                                    \
 399           "Deoptimize random frames on random exit from the runtime system")\
 400                                                                             \
 401   notproduct(bool, ZombieALot, false,                                       \
 402           "Create non-entrant nmethods at exit from the runtime system")    \
 403                                                                             \
 404   notproduct(bool, WalkStackALot, false,                                    \
 405           "Trace stack (no print) at every exit from the runtime system")   \
 406                                                                             \
 407   develop(bool, DeoptimizeObjectsALot, false,                               \
 408           "For testing purposes concurrent threads revert optimizations "   \
 409           "based on escape analysis at intervals given with "               \
 410           "DeoptimizeObjectsALotInterval=n. The thread count is given "     \
 411           "with DeoptimizeObjectsALotThreadCountSingle and "                \
 412           "DeoptimizeObjectsALotThreadCountAll.")                           \
 413                                                                             \
 414   develop(uint64_t, DeoptimizeObjectsALotInterval, 5,                       \
 415           "Interval for DeoptimizeObjectsALot.")                            \
 416           range(0, max_jlong)                                               \
 417                                                                             \
 418   develop(int, DeoptimizeObjectsALotThreadCountSingle, 1,                   \
 419           "The number of threads that revert optimizations based on "       \
 420           "escape analysis for a single thread if DeoptimizeObjectsALot "   \
 421           "is enabled. The target thread is selected round robin." )        \
 422           range(0, max_jint)                                                \
 423                                                                             \
 424   develop(int, DeoptimizeObjectsALotThreadCountAll, 1,                      \
 425           "The number of threads that revert optimizations based on "       \
 426           "escape analysis for all threads if DeoptimizeObjectsALot "       \
 427           "is enabled." )                                                   \
 428           range(0, max_jint)                                                \
 429                                                                             \
 430   notproduct(bool, VerifyLastFrame, false,                                  \
 431           "Verify oops on last frame on entry to VM")                       \
 432                                                                             \
 433   product(bool, SafepointTimeout, false,                                    \
 434           "Time out and warn or fail after SafepointTimeoutDelay "          \
 435           "milliseconds if failed to reach safepoint")                      \
 436                                                                             \
 437   product(bool, AbortVMOnSafepointTimeout, false, DIAGNOSTIC,               \
 438           "Abort upon failure to reach safepoint (see SafepointTimeout)")   \
 439                                                                             \
 440   product(uint64_t, AbortVMOnSafepointTimeoutDelay, 0, DIAGNOSTIC,          \
 441           "Delay in milliseconds for option AbortVMOnSafepointTimeout")     \
 442           range(0, max_jlong)                                               \
 443                                                                             \
 444   product(bool, AbortVMOnVMOperationTimeout, false, DIAGNOSTIC,             \
 445           "Abort upon failure to complete VM operation promptly")           \
 446                                                                             \
 447   product(intx, AbortVMOnVMOperationTimeoutDelay, 1000, DIAGNOSTIC,         \
 448           "Delay in milliseconds for option AbortVMOnVMOperationTimeout")   \
 449           range(0, max_intx)                                                \
 450                                                                             \
 451   product(bool, MaxFDLimit, true,                                           \
 452           "Bump the number of file descriptors to maximum (Unix only)")     \
 453                                                                             \
 454   product(bool, LogEvents, true, DIAGNOSTIC,                                \
 455           "Enable the various ring buffer event logs")                      \
 456                                                                             \
 457   product(int, LogEventsBufferEntries, 20, DIAGNOSTIC,                      \
 458           "Number of ring buffer event logs")                               \
 459           range(1, NOT_LP64(1*K) LP64_ONLY(1*M))                            \
 460                                                                             \
 461   product(bool, BytecodeVerificationRemote, true, DIAGNOSTIC,               \
 462           "Enable the Java bytecode verifier for remote classes")           \
 463                                                                             \
 464   product(bool, BytecodeVerificationLocal, false, DIAGNOSTIC,               \
 465           "Enable the Java bytecode verifier for local classes")            \
 466                                                                             \
 467   develop(bool, VerifyStackAtCalls, false,                                  \
 468           "Verify that the stack pointer is unchanged after calls")         \
 469                                                                             \
 470   develop(bool, TraceJavaAssertions, false,                                 \
 471           "Trace java language assertions")                                 \
 472                                                                             \
 473   notproduct(bool, VerifyCodeCache, false,                                  \
 474           "Verify code cache on memory allocation/deallocation")            \
 475                                                                             \
 476   develop(bool, ZapResourceArea, trueInDebug,                               \
 477           "Zap freed resource/arena space")                                 \
 478                                                                             \
 479   notproduct(bool, ZapVMHandleArea, trueInDebug,                            \
 480           "Zap freed VM handle space")                                      \
 481                                                                             \
 482   notproduct(bool, ZapStackSegments, trueInDebug,                           \
 483           "Zap allocated/freed stack segments")                             \
 484                                                                             \
 485   develop(bool, ZapUnusedHeapArea, trueInDebug,                             \
 486           "Zap unused heap space")                                          \
 487                                                                             \
 488   develop(bool, CheckZapUnusedHeapArea, false,                              \
 489           "Check zapping of unused heap space")                             \
 490                                                                             \
 491   develop(bool, ZapFillerObjects, trueInDebug,                              \
 492           "Zap filler objects")                                             \
 493                                                                             \
 494   product(bool, ExecutingUnitTests, false,                                  \
 495           "Whether the JVM is running unit tests or not")                   \
 496                                                                             \
 497   develop(uint, ErrorHandlerTest, 0,                                        \
 498           "If > 0, provokes an error after VM initialization; the value "   \
 499           "determines which error to provoke. See controlled_crash() "      \
 500           "in vmError.cpp.")                                                \
 501           range(0, 17)                                                      \
 502                                                                             \
 503   develop(uint, TestCrashInErrorHandler, 0,                                 \
 504           "If > 0, provokes an error inside VM error handler (a secondary " \
 505           "crash). see controlled_crash() in vmError.cpp")                  \
 506           range(0, 17)                                                      \
 507                                                                             \
 508   develop(bool, TestSafeFetchInErrorHandler, false   ,                      \
 509           "If true, tests SafeFetch inside error handler.")                 \
 510                                                                             \
 511   develop(bool, TestUnresponsiveErrorHandler, false,                        \
 512           "If true, simulates an unresponsive error handler.")              \
 513                                                                             \
 514   develop(bool, Verbose, false,                                             \
 515           "Print additional debugging information from other modes")        \
 516                                                                             \
 517   develop(bool, PrintMiscellaneous, false,                                  \
 518           "Print uncategorized debugging information (requires +Verbose)")  \
 519                                                                             \
 520   develop(bool, WizardMode, false,                                          \
 521           "Print much more debugging information")                          \
 522                                                                             \
 523   product(bool, ShowMessageBoxOnError, false,                               \
 524           "Keep process alive on VM fatal error")                           \
 525                                                                             \
 526   product(bool, CreateCoredumpOnCrash, true,                                \
 527           "Create core/mini dump on VM fatal error")                        \
 528                                                                             \
 529   product(uint64_t, ErrorLogTimeout, 2 * 60,                                \
 530           "Timeout, in seconds, to limit the time spent on writing an "     \
 531           "error log in case of a crash.")                                  \
 532           range(0, (uint64_t)max_jlong/1000)                                \
 533                                                                             \
 534   product(bool, ErrorLogSecondaryErrorDetails, false, DIAGNOSTIC,           \
 535           "If enabled, show details on secondary crashes in the error log") \
 536                                                                             \
 537   develop(intx, TraceDwarfLevel, 0,                                         \
 538           "Debug levels for the dwarf parser")                              \
 539           range(0, 4)                                                       \
 540                                                                             \
 541   product(bool, SuppressFatalErrorMessage, false,                           \
 542           "Report NO fatal error message (avoid deadlock)")                 \
 543                                                                             \
 544   product(ccstrlist, OnError, "",                                           \
 545           "Run user-defined commands on fatal error; see VMError.cpp "      \
 546           "for examples")                                                   \
 547                                                                             \
 548   product(ccstrlist, OnOutOfMemoryError, "",                                \
 549           "Run user-defined commands on first java.lang.OutOfMemoryError "  \
 550           "thrown from JVM")                                                \
 551                                                                             \
 552   product(bool, HeapDumpBeforeFullGC, false, MANAGEABLE,                    \
 553           "Dump heap to file before any major stop-the-world GC "           \
 554           "(also see FullGCHeapDumpLimit)")                                 \
 555                                                                             \
 556   product(bool, HeapDumpAfterFullGC, false, MANAGEABLE,                     \
 557           "Dump heap to file after any major stop-the-world GC "            \
 558           "(also see FullGCHeapDumpLimit)")                                 \
 559                                                                             \
 560   product(uint, FullGCHeapDumpLimit, 0, MANAGEABLE,                         \
 561           "Limit the number of heap dumps triggered by "                    \
 562           "HeapDumpBeforeFullGC or HeapDumpAfterFullGC "                    \
 563           "(0 means no limit)")                                             \
 564                                                                             \
 565   product(bool, HeapDumpOnOutOfMemoryError, false, MANAGEABLE,              \
 566           "Dump heap to file when java.lang.OutOfMemoryError is thrown "    \
 567           "from JVM")                                                       \
 568                                                                             \
 569   product(ccstr, HeapDumpPath, nullptr, MANAGEABLE,                         \
 570           "When HeapDumpOnOutOfMemoryError is on, the path (filename or "   \
 571           "directory) of the dump file (defaults to java_pid<pid>.hprof "   \
 572           "in the working directory)")                                      \
 573                                                                             \
 574   product(int, HeapDumpGzipLevel, 0, MANAGEABLE,                            \
 575           "When HeapDumpOnOutOfMemoryError is on, the gzip compression "    \
 576           "level of the dump file. 0 (the default) disables gzip "          \
 577           "compression. Otherwise the level must be between 1 and 9.")      \
 578           range(0, 9)                                                       \
 579                                                                             \
 580   product(ccstr, NativeMemoryTracking, DEBUG_ONLY("summary") NOT_DEBUG("off"), \
 581           "Native memory tracking options")                                 \
 582                                                                             \
 583   product(bool, PrintNMTStatistics, false, DIAGNOSTIC,                      \
 584           "Print native memory tracking summary data if it is on")          \
 585                                                                             \
 586   product(bool, LogCompilation, false, DIAGNOSTIC,                          \
 587           "Log compilation activity in detail to LogFile")                  \
 588                                                                             \
 589   product(bool, PrintCompilation, false,                                    \
 590           "Print compilations")                                             \
 591                                                                             \
 592   product(intx, RepeatCompilation, 0, DIAGNOSTIC,                           \
 593           "Repeat compilation without installing code (number of times)")   \
 594           range(0, max_jint)                                                \
 595                                                                             \
 596   product(bool, PrintExtendedThreadInfo, false,                             \
 597           "Print more information in thread dump")                          \
 598                                                                             \
 599   product(intx, ScavengeRootsInCode, 2, DIAGNOSTIC,                         \
 600           "0: do not allow scavengable oops in the code cache; "            \
 601           "1: allow scavenging from the code cache; "                       \
 602           "2: emit as many constants as the compiler can see")              \
 603           range(0, 2)                                                       \
 604                                                                             \
 605   product(bool, AlwaysRestoreFPU, false,                                    \
 606           "Restore the FPU control word after every JNI call (expensive)")  \
 607                                                                             \
 608   product(bool, PrintCompilation2, false, DIAGNOSTIC,                       \
 609           "Print additional statistics per compilation")                    \
 610                                                                             \
 611   product(bool, PrintAdapterHandlers, false, DIAGNOSTIC,                    \
 612           "Print code generated for i2c/c2i adapters")                      \
 613                                                                             \
 614   product(bool, VerifyAdapterCalls, trueInDebug, DIAGNOSTIC,                \
 615           "Verify that i2c/c2i adapters are called properly")               \
 616                                                                             \
 617   develop(bool, VerifyAdapterSharing, false,                                \
 618           "Verify that the code for shared adapters is the equivalent")     \
 619                                                                             \
 620   product(bool, PrintAssembly, false, DIAGNOSTIC,                           \
 621           "Print assembly code (using external disassembler.so)")           \
 622                                                                             \
 623   product(ccstr, PrintAssemblyOptions, nullptr, DIAGNOSTIC,                 \
 624           "Print options string passed to disassembler.so")                 \
 625                                                                             \
 626   notproduct(bool, PrintNMethodStatistics, false,                           \
 627           "Print a summary statistic for the generated nmethods")           \
 628                                                                             \
 629   product(bool, PrintNMethods, false, DIAGNOSTIC,                           \
 630           "Print assembly code for nmethods when generated")                \
 631                                                                             \
 632   product(bool, PrintNativeNMethods, false, DIAGNOSTIC,                     \
 633           "Print assembly code for native nmethods when generated")         \
 634                                                                             \
 635   develop(bool, PrintDebugInfo, false,                                      \
 636           "Print debug information for all nmethods when generated")        \
 637                                                                             \
 638   develop(bool, PrintRelocations, false,                                    \
 639           "Print relocation information for all nmethods when generated")   \
 640                                                                             \
 641   develop(bool, PrintDependencies, false,                                   \
 642           "Print dependency information for all nmethods when generated")   \
 643                                                                             \
 644   develop(bool, PrintExceptionHandlers, false,                              \
 645           "Print exception handler tables for all nmethods when generated") \
 646                                                                             \
 647   develop(bool, StressCompiledExceptionHandlers, false,                     \
 648           "Exercise compiled exception handlers")                           \
 649                                                                             \
 650   develop(bool, InterceptOSException, false,                                \
 651           "Start debugger when an implicit OS (e.g. null pointer) "         \
 652           "exception happens")                                              \
 653                                                                             \
 654   product(bool, PrintCodeCache, false,                                      \
 655           "Print the code cache memory usage when exiting")                 \
 656                                                                             \
 657   develop(bool, PrintCodeCache2, false,                                     \
 658           "Print detailed usage information on the code cache when exiting")\
 659                                                                             \
 660   product(bool, PrintCodeCacheOnCompilation, false,                         \
 661           "Print the code cache memory usage each time a method is "        \
 662           "compiled")                                                       \
 663                                                                             \
 664   product(bool, PrintCodeHeapAnalytics, false, DIAGNOSTIC,                  \
 665           "Print code heap usage statistics on exit and on full condition") \
 666                                                                             \
 667   product(bool, PrintStubCode, false, DIAGNOSTIC,                           \
 668           "Print generated stub code")                                      \
 669                                                                             \
 670   product(bool, StackTraceInThrowable, true,                                \
 671           "Collect backtrace in throwable when exception happens")          \
 672                                                                             \
 673   product(bool, OmitStackTraceInFastThrow, true,                            \
 674           "Omit backtraces for some 'hot' exceptions in optimized code")    \
 675                                                                             \
 676   product(bool, ShowCodeDetailsInExceptionMessages, true, MANAGEABLE,       \
 677           "Show exception messages from RuntimeExceptions that contain "    \
 678           "snippets of the failing code. Disable this to improve privacy.") \
 679                                                                             \
 680   product(bool, PrintWarnings, true,                                        \
 681           "Print JVM warnings to output stream")                            \
 682                                                                             \
 683   product(bool, RegisterFinalizersAtInit, true,                             \
 684           "(Deprecated) Register finalizable objects at end of "            \
 685           "Object.<init> or after allocation")                              \
 686                                                                             \
 687   develop(bool, RegisterReferences, true,                                   \
 688           "Tell whether the VM should register soft/weak/final/phantom "    \
 689           "references")                                                     \
 690                                                                             \
 691   develop(bool, PrintCodeCacheExtension, false,                             \
 692           "Print extension of code cache")                                  \
 693                                                                             \
 694   develop(bool, UsePrivilegedStack, true,                                   \
 695           "Enable the security JVM functions")                              \
 696                                                                             \
 697   product(bool, ClassUnloading, true,                                       \
 698           "Do unloading of classes")                                        \
 699                                                                             \
 700   product(bool, ClassUnloadingWithConcurrentMark, true,                     \
 701           "Do unloading of classes with a concurrent marking cycle")        \
 702                                                                             \
 703   notproduct(bool, PrintSystemDictionaryAtExit, false,                      \
 704           "Print the system dictionary at exit")                            \
 705                                                                             \
 706   notproduct(bool, PrintClassLoaderDataGraphAtExit, false,                  \
 707           "Print the class loader data graph at exit")                      \
 708                                                                             \
 709   product(bool, AllowParallelDefineClass, false,                            \
 710           "Allow parallel defineClass requests for class loaders "          \
 711           "registering as parallel capable")                                \
 712                                                                             \
 713   product_pd(bool, DontYieldALot,                                           \
 714           "Throw away obvious excess yield calls")                          \
 715                                                                             \
 716   product(bool, DisablePrimordialThreadGuardPages, false, EXPERIMENTAL,     \
 717                "Disable the use of stack guard pages if the JVM is loaded " \
 718                "on the primordial process thread")                          \
 719                                                                             \
 720   product(bool, DoJVMTIVirtualThreadTransitions, true, EXPERIMENTAL,        \
 721                "Do JVMTI virtual thread mount/unmount transitions "         \
 722                "(disabling this flag implies no JVMTI events are posted)")  \
 723                                                                             \
 724   /* notice: the max range value here is max_jint, not max_intx  */         \
 725   /* because of overflow issue                                   */         \
 726   product(intx, AsyncDeflationInterval, 250, DIAGNOSTIC,                    \
 727           "Async deflate idle monitors every so many milliseconds when "    \
 728           "MonitorUsedDeflationThreshold is exceeded (0 is off).")          \
 729           range(0, max_jint)                                                \
 730                                                                             \
 731   /* notice: the max range value here is max_jint, not max_intx  */         \
 732   /* because of overflow issue                                   */         \
 733   product(intx, GuaranteedAsyncDeflationInterval, 60000, DIAGNOSTIC,        \
 734           "Async deflate idle monitors every so many milliseconds even "    \
 735           "when MonitorUsedDeflationThreshold is NOT exceeded (0 is off).") \
 736           range(0, max_jint)                                                \
 737                                                                             \
 738   product(size_t, AvgMonitorsPerThreadEstimate, 1024, DIAGNOSTIC,           \
 739           "Used to estimate a variable ceiling based on number of threads " \
 740           "for use with MonitorUsedDeflationThreshold (0 is off).")         \
 741           range(0, max_uintx)                                               \
 742                                                                             \
 743   /* notice: the max range value here is max_jint, not max_intx  */         \
 744   /* because of overflow issue                                   */         \
 745   product(intx, MonitorDeflationMax, 1000000, DIAGNOSTIC,                   \
 746           "The maximum number of monitors to deflate, unlink and delete "   \
 747           "at one time (minimum is 1024).")                                 \
 748           range(1024, max_jint)                                             \
 749                                                                             \
 750   product(intx, MonitorUnlinkBatch, 500, DIAGNOSTIC,                        \
 751           "The maximum number of monitors to unlink in one batch. ")        \
 752           range(1, max_jint)                                                \
 753                                                                             \
 754   product(int, MonitorUsedDeflationThreshold, 90, DIAGNOSTIC,               \
 755           "Percentage of used monitors before triggering deflation (0 is "  \
 756           "off). The check is performed on GuaranteedSafepointInterval, "   \
 757           "AsyncDeflationInterval or GuaranteedAsyncDeflationInterval, "    \
 758           "whichever is lower.")                                            \
 759           range(0, 100)                                                     \
 760                                                                             \
 761   product(uintx, NoAsyncDeflationProgressMax, 3, DIAGNOSTIC,                \
 762           "Max number of no progress async deflation attempts to tolerate " \
 763           "before adjusting the in_use_list_ceiling up (0 is off).")        \
 764           range(0, max_uintx)                                               \
 765                                                                             \
 766   product(intx, hashCode, 5, EXPERIMENTAL,                                  \
 767                "(Unstable) select hashCode generation algorithm")           \
 768                                                                             \
 769   product(bool, ReduceSignalUsage, false,                                   \
 770           "Reduce the use of OS signals in Java and/or the VM")             \
 771                                                                             \
 772   develop(bool, LoadLineNumberTables, true,                                 \
 773           "Tell whether the class file parser loads line number tables")    \
 774                                                                             \
 775   develop(bool, LoadLocalVariableTables, true,                              \
 776           "Tell whether the class file parser loads local variable tables") \
 777                                                                             \
 778   develop(bool, LoadLocalVariableTypeTables, true,                          \
 779           "Tell whether the class file parser loads local variable type"    \
 780           "tables")                                                         \
 781                                                                             \
 782   product(bool, AllowUserSignalHandlers, false,                             \
 783           "Application will install primary signal handlers for the JVM "   \
 784           "(Unix only)")                                                    \
 785                                                                             \
 786   product(bool, UseSignalChaining, true,                                    \
 787           "Use signal-chaining to invoke signal handlers installed "        \
 788           "by the application (Unix only)")                                 \
 789                                                                             \
 790   product(bool, RestoreMXCSROnJNICalls, false,                              \
 791           "Restore MXCSR when returning from JNI calls")                    \
 792                                                                             \
 793   product(bool, CheckJNICalls, false,                                       \
 794           "Verify all arguments to JNI calls")                              \
 795                                                                             \
 796   product(bool, UseFastJNIAccessors, true,                                  \
 797           "Use optimized versions of Get<Primitive>Field")                  \
 798                                                                             \
 799   product(intx, MaxJNILocalCapacity, 65536,                                 \
 800           "Maximum allowable local JNI handle capacity to "                 \
 801           "EnsureLocalCapacity() and PushLocalFrame(), "                    \
 802           "where <= 0 is unlimited, default: 65536")                        \
 803           range(min_intx, max_intx)                                         \
 804                                                                             \
 805   product(bool, EagerXrunInit, false,                                       \
 806           "Eagerly initialize -Xrun libraries; allows startup profiling, "  \
 807           "but not all -Xrun libraries may support the state of the VM "    \
 808           "at this time")                                                   \
 809                                                                             \
 810   product(bool, PreserveAllAnnotations, false,                              \
 811           "Preserve RuntimeInvisibleAnnotations as well "                   \
 812           "as RuntimeVisibleAnnotations")                                   \
 813                                                                             \
 814   develop(uintx, PreallocatedOutOfMemoryErrorCount, 4,                      \
 815           "Number of OutOfMemoryErrors preallocated with backtrace")        \
 816                                                                             \
 817   product(bool, UseXMMForArrayCopy, false,                                  \
 818           "Use SSE2 MOVQ instruction for Arraycopy")                        \
 819                                                                             \
 820   notproduct(bool, PrintFieldLayout, false,                                 \
 821           "Print field layout for each class")                              \
 822                                                                             \
 823   /* Need to limit the extent of the padding to reasonable size.          */\
 824   /* 8K is well beyond the reasonable HW cache line size, even with       */\
 825   /* aggressive prefetching, while still leaving the room for segregating */\
 826   /* among the distinct pages.                                            */\
 827   product(int, ContendedPaddingWidth, 128,                                  \
 828           "How many bytes to pad the fields/classes marked @Contended with")\
 829           range(0, 8192)                                                    \
 830           constraint(ContendedPaddingWidthConstraintFunc,AfterErgo)         \
 831                                                                             \
 832   product(bool, EnableContended, true,                                      \
 833           "Enable @Contended annotation support")                           \
 834                                                                             \
 835   product(bool, RestrictContended, true,                                    \
 836           "Restrict @Contended to trusted classes")                         \
 837                                                                             \
 838   product(int, DiagnoseSyncOnValueBasedClasses, 0, DIAGNOSTIC,              \
 839              "Detect and take action upon identifying synchronization on "  \
 840              "value based classes. Modes: "                                 \
 841              "0: off; "                                                     \
 842              "1: exit with fatal error; "                                   \
 843              "2: log message to stdout. Output file can be specified with " \
 844              "   -Xlog:valuebasedclasses. If JFR is running it will "       \
 845              "   also generate JFR events.")                                \
 846              range(0, 2)                                                    \
 847                                                                             \
 848   product(bool, ExitOnOutOfMemoryError, false,                              \
 849           "JVM exits on the first occurrence of an out-of-memory error "    \
 850           "thrown from JVM")                                                \
 851                                                                             \
 852   product(bool, CrashOnOutOfMemoryError, false,                             \
 853           "JVM aborts, producing an error log and core/mini dump, on the "  \
 854           "first occurrence of an out-of-memory error thrown from JVM")     \
 855                                                                             \
 856   product(intx, UserThreadWaitAttemptsAtExit, 30,                           \
 857           "The number of times to wait for user threads to stop executing " \
 858           "native code during JVM exit. Each wait lasts 10 milliseconds. "  \
 859           "The maximum number of waits is 1000, to wait at most 10 "        \
 860           "seconds.")                                                       \
 861           range(0, 1000)                                                    \
 862                                                                             \
 863   /* tracing */                                                             \
 864                                                                             \
 865   develop(bool, StressRewriter, false,                                      \
 866           "Stress linktime bytecode rewriting")                             \
 867                                                                             \
 868   product(ccstr, TraceJVMTI, nullptr,                                       \
 869           "Trace flags for JVMTI functions and events")                     \
 870                                                                             \
 871   product(bool, StressLdcRewrite, false, DIAGNOSTIC,                        \
 872           "Force ldc -> ldc_w rewrite during RedefineClasses. "             \
 873           "This option can change an EMCP method into an obsolete method "  \
 874           "and can affect tests that expect specific methods to be EMCP. "  \
 875           "This option should be used with caution.")                       \
 876                                                                             \
 877   product(bool, AllowRedefinitionToAddDeleteMethods, false,                 \
 878           "(Deprecated) Allow redefinition to add and delete private "      \
 879           "static or final methods for compatibility with old releases")    \
 880                                                                             \
 881   develop(bool, TraceBytecodes, false,                                      \
 882           "Trace bytecode execution")                                       \
 883                                                                             \
 884   notproduct(bool, TraceInvocationCounterOverflow, false,                   \
 885           "Trace method invocation counter overflow")                       \
 886                                                                             \
 887   develop(bool, VerifyDependencies, trueInDebug,                            \
 888           "Exercise and verify the compilation dependency mechanism")       \
 889                                                                             \
 890   develop(bool, TraceNewOopMapGeneration, false,                            \
 891           "Trace OopMapGeneration")                                         \
 892                                                                             \
 893   develop(bool, TraceNewOopMapGenerationDetailed, false,                    \
 894           "Trace OopMapGeneration: print detailed cell states")             \
 895                                                                             \
 896   develop(bool, TimeOopMap, false,                                          \
 897           "Time calls to GenerateOopMap::compute_map() in sum")             \
 898                                                                             \
 899   develop(bool, TimeOopMap2, false,                                         \
 900           "Time calls to GenerateOopMap::compute_map() individually")       \
 901                                                                             \
 902   develop(bool, TraceOopMapRewrites, false,                                 \
 903           "Trace rewriting of methods during oop map generation")           \
 904                                                                             \
 905   develop(bool, FLSVerifyDictionary, false,                                 \
 906           "Do lots of (expensive) FLS dictionary verification")             \
 907                                                                             \
 908   product(uintx, ProcessDistributionStride, 4,                              \
 909           "Stride through processors when distributing processes")          \
 910           range(0, max_juint)                                               \
 911                                                                             \
 912   develop(bool, TraceFinalizerRegistration, false,                          \
 913           "Trace registration of final references")                         \
 914                                                                             \
 915   product(bool, IgnoreEmptyClassPaths, false,                               \
 916           "Ignore empty path elements in -classpath")                       \
 917                                                                             \
 918   product(bool, PrintHeapAtSIGBREAK, true,                                  \
 919           "Print heap layout in response to SIGBREAK")                      \
 920                                                                             \
 921   product(bool, PrintClassHistogram, false, MANAGEABLE,                     \
 922           "Print a histogram of class instances")                           \
 923                                                                             \
 924   product(double, ObjectCountCutOffPercent, 0.5, EXPERIMENTAL,              \
 925           "The percentage of the used heap that the instances of a class "  \
 926           "must occupy for the class to generate a trace event")            \
 927           range(0.0, 100.0)                                                 \
 928                                                                             \
 929   /* JVMTI heap profiling */                                                \
 930                                                                             \
 931   product(bool, VerifyBeforeIteration, false, DIAGNOSTIC,                   \
 932           "Verify memory system before JVMTI iteration")                    \
 933                                                                             \
 934   /* compiler */                                                            \
 935                                                                             \
 936   /* notice: the max range value here is max_jint, not max_intx  */         \
 937   /* because of overflow issue                                   */         \
 938   product(intx, CICompilerCount, CI_COMPILER_COUNT,                         \
 939           "Number of compiler threads to run")                              \
 940           range(0, max_jint)                                                \
 941           constraint(CICompilerCountConstraintFunc, AfterErgo)              \
 942                                                                             \
 943   product(bool, UseDynamicNumberOfCompilerThreads, true,                    \
 944           "Dynamically choose the number of parallel compiler threads")     \
 945                                                                             \
 946   product(bool, ReduceNumberOfCompilerThreads, true, DIAGNOSTIC,            \
 947              "Reduce the number of parallel compiler threads when they "    \
 948              "are not used")                                                \
 949                                                                             \
 950   product(bool, TraceCompilerThreads, false, DIAGNOSTIC,                    \
 951              "Trace creation and removal of compiler threads")              \
 952                                                                             \
 953   product(ccstr, LogClassLoadingCauseFor, nullptr,                          \
 954           "Apply -Xlog:class+load+cause* to classes whose fully "           \
 955           "qualified name contains this string (\"*\" matches "             \
 956           "any class).")                                                    \
 957                                                                             \
 958   develop(bool, InjectCompilerCreationFailure, false,                       \
 959           "Inject thread creation failures for "                            \
 960           "UseDynamicNumberOfCompilerThreads")                              \
 961                                                                             \
 962   develop(bool, GenerateSynchronizationCode, true,                          \
 963           "generate locking/unlocking code for synchronized methods and "   \
 964           "monitors")                                                       \
 965                                                                             \
 966   product_pd(bool, ImplicitNullChecks, DIAGNOSTIC,                          \
 967           "Generate code for implicit null checks")                         \
 968                                                                             \
 969   product_pd(bool, TrapBasedNullChecks,                                     \
 970           "Generate code for null checks that uses a cmp and trap "         \
 971           "instruction raising SIGTRAP.  This is only used if an access to" \
 972           "null (+offset) will not raise a SIGSEGV, i.e.,"                  \
 973           "ImplicitNullChecks don't work (PPC64).")                         \
 974                                                                             \
 975   product(bool, EnableThreadSMRStatistics, trueInDebug, DIAGNOSTIC,         \
 976              "Enable Thread SMR Statistics")                                \
 977                                                                             \
 978   product(bool, UseNotificationThread, true,                                \
 979           "Use Notification Thread")                                        \
 980                                                                             \
 981   product(bool, Inline, true,                                               \
 982           "Enable inlining")                                                \
 983                                                                             \
 984   product(bool, ClipInlining, true,                                         \
 985           "Clip inlining if aggregate method exceeds DesiredMethodLimit")   \
 986                                                                             \
 987   develop(bool, UseCHA, true,                                               \
 988           "Enable CHA")                                                     \
 989                                                                             \
 990   product(bool, UseVtableBasedCHA, true,  DIAGNOSTIC,                       \
 991           "Use vtable information during CHA")                              \
 992                                                                             \
 993   product(bool, UseTypeProfile, true,                                       \
 994           "Check interpreter profile for historically monomorphic calls")   \
 995                                                                             \
 996   product(bool, PrintInlining, false, DIAGNOSTIC,                           \
 997           "Print inlining optimizations")                                   \
 998                                                                             \
 999   product(bool, UsePopCountInstruction, false,                              \
1000           "Use population count instruction")                               \
1001                                                                             \
1002   develop(bool, TraceMethodReplacement, false,                              \
1003           "Print when methods are replaced do to recompilation")            \
1004                                                                             \
1005   product(bool, PrintMethodFlushingStatistics, false, DIAGNOSTIC,           \
1006           "print statistics about method flushing")                         \
1007                                                                             \
1008   product(intx, MinPassesBeforeFlush, 10, DIAGNOSTIC,                       \
1009           "Minimum number of sweeper passes before an nmethod "             \
1010           "can be flushed")                                                 \
1011           range(0, max_intx)                                                \
1012                                                                             \
1013   develop(bool, StressCodeBuffers, false,                                   \
1014           "Exercise code buffer expansion and other rare state changes")    \
1015                                                                             \
1016   product(bool, DebugNonSafepoints, trueInDebug, DIAGNOSTIC,                \
1017           "Generate extra debugging information for non-safepoints in "     \
1018           "nmethods")                                                       \
1019                                                                             \
1020   product(bool, PrintVMOptions, false,                                      \
1021           "Print flags that appeared on the command line")                  \
1022                                                                             \
1023   product(bool, IgnoreUnrecognizedVMOptions, false,                         \
1024           "Ignore unrecognized VM options")                                 \
1025                                                                             \
1026   product(bool, PrintCommandLineFlags, false,                               \
1027           "Print flags specified on command line or set by ergonomics")     \
1028                                                                             \
1029   product(bool, PrintFlagsInitial, false,                                   \
1030           "Print all VM flags before argument processing and exit VM")      \
1031                                                                             \
1032   product(bool, PrintFlagsFinal, false,                                     \
1033           "Print all VM flags after argument and ergonomic processing")     \
1034                                                                             \
1035   notproduct(bool, PrintFlagsWithComments, false,                           \
1036           "Print all VM flags with default values and descriptions and "    \
1037           "exit")                                                           \
1038                                                                             \
1039   product(bool, PrintFlagsRanges, false,                                    \
1040           "Print VM flags and their ranges")                                \
1041                                                                             \
1042   product(bool, SerializeVMOutput, true, DIAGNOSTIC,                        \
1043           "Use a mutex to serialize output to tty and LogFile")             \
1044                                                                             \
1045   product(bool, DisplayVMOutput, true, DIAGNOSTIC,                          \
1046           "Display all VM output on the tty, independently of LogVMOutput") \
1047                                                                             \
1048   product(bool, LogVMOutput, false, DIAGNOSTIC,                             \
1049           "Save VM output to LogFile")                                      \
1050                                                                             \
1051   product(ccstr, LogFile, nullptr, DIAGNOSTIC,                              \
1052           "If LogVMOutput or LogCompilation is on, save VM output to "      \
1053           "this file [default: ./hotspot_pid%p.log] (%p replaced with pid)")\
1054                                                                             \
1055   product(ccstr, ErrorFile, nullptr,                                        \
1056           "If an error occurs, save the error data to this file "           \
1057           "[default: ./hs_err_pid%p.log] (%p replaced with pid)")           \
1058                                                                             \
1059   product(bool, ExtensiveErrorReports,                                      \
1060           PRODUCT_ONLY(false) NOT_PRODUCT(true),                            \
1061           "Error reports are more extensive.")                              \
1062                                                                             \
1063   product(bool, DisplayVMOutputToStderr, false,                             \
1064           "If DisplayVMOutput is true, display all VM output to stderr")    \
1065                                                                             \
1066   product(bool, DisplayVMOutputToStdout, false,                             \
1067           "If DisplayVMOutput is true, display all VM output to stdout")    \
1068                                                                             \
1069   product(bool, ErrorFileToStderr, false,                                   \
1070           "If true, error data is printed to stderr instead of a file")     \
1071                                                                             \
1072   product(bool, ErrorFileToStdout, false,                                   \
1073           "If true, error data is printed to stdout instead of a file")     \
1074                                                                             \
1075   develop(bool, VerifyHeavyMonitors, false,                                 \
1076           "Checks that no stack locking happens when using "                \
1077           "-XX:LockingMode=0 (LM_MONITOR)")                                 \
1078                                                                             \
1079   product(bool, PrintStringTableStatistics, false,                          \
1080           "print statistics about the StringTable and SymbolTable")         \
1081                                                                             \
1082   product(bool, VerifyStringTableAtExit, false, DIAGNOSTIC,                 \
1083           "verify StringTable contents at exit")                            \
1084                                                                             \
1085   notproduct(bool, PrintSymbolTableSizeHistogram, false,                    \
1086           "print histogram of the symbol table")                            \
1087                                                                             \
1088   product(ccstr, AbortVMOnException, nullptr, DIAGNOSTIC,                   \
1089           "Call fatal if this exception is thrown.  Example: "              \
1090           "java -XX:AbortVMOnException=java.lang.NullPointerException Foo") \
1091                                                                             \
1092   product(ccstr, AbortVMOnExceptionMessage, nullptr, DIAGNOSTIC,            \
1093           "Call fatal if the exception pointed by AbortVMOnException "      \
1094           "has this message")                                               \
1095                                                                             \
1096   develop(bool, DebugVtables, false,                                        \
1097           "add debugging code to vtable dispatch")                          \
1098                                                                             \
1099   product(bool, RangeCheckElimination, true,                                \
1100           "Eliminate range checks")                                         \
1101                                                                             \
1102   develop_pd(bool, UncommonNullCast,                                        \
1103           "track occurrences of null in casts; adjust compiler tactics")    \
1104                                                                             \
1105   develop(bool, TypeProfileCasts,  true,                                    \
1106           "treat casts like calls for purposes of type profiling")          \
1107                                                                             \
1108   develop(bool, TraceLivenessGen, false,                                    \
1109           "Trace the generation of liveness analysis information")          \
1110                                                                             \
1111   notproduct(bool, TraceLivenessQuery, false,                               \
1112           "Trace queries of liveness analysis information")                 \
1113                                                                             \
1114   notproduct(bool, CollectIndexSetStatistics, false,                        \
1115           "Collect information about IndexSets")                            \
1116                                                                             \
1117   develop(int, FastAllocateSizeLimit, 128*K,                                \
1118           /* Note:  This value is zero mod 1<<13 for a cheap sparc set. */  \
1119           "Inline allocations larger than this in doublewords must go slow")\
1120                                                                             \
1121   product_pd(bool, CompactStrings,                                          \
1122           "Enable Strings to use single byte chars in backing store")       \
1123                                                                             \
1124   product_pd(uint, TypeProfileLevel,                                        \
1125           "=XYZ, with Z: Type profiling of arguments at call; "             \
1126                      "Y: Type profiling of return value at call; "          \
1127                      "X: Type profiling of parameters to methods; "         \
1128           "X, Y and Z in 0=off ; 1=jsr292 only; 2=all methods")             \
1129           constraint(TypeProfileLevelConstraintFunc, AfterErgo)             \
1130                                                                             \
1131   product(int, TypeProfileArgsLimit,     2,                                 \
1132           "max number of call arguments to consider for type profiling")    \
1133           range(0, 16)                                                      \
1134                                                                             \
1135   product(int, TypeProfileParmsLimit,    2,                                 \
1136           "max number of incoming parameters to consider for type profiling"\
1137           ", -1 for all")                                                   \
1138           range(-1, 64)                                                     \
1139                                                                             \
1140   /* statistics */                                                          \
1141   develop(bool, CountCompiledCalls, false,                                  \
1142           "Count method invocations")                                       \
1143                                                                             \
1144   notproduct(bool, ICMissHistogram, false,                                  \
1145           "Produce histogram of IC misses")                                 \
1146                                                                             \
1147   /* interpreter */                                                         \
1148   product_pd(bool, RewriteBytecodes,                                        \
1149           "Allow rewriting of bytecodes (bytecodes are not immutable)")     \
1150                                                                             \
1151   product_pd(bool, RewriteFrequentPairs,                                    \
1152           "Rewrite frequently used bytecode pairs into a single bytecode")  \
1153                                                                             \
1154   product(bool, PrintInterpreter, false, DIAGNOSTIC,                        \
1155           "Print the generated interpreter code")                           \
1156                                                                             \
1157   product(bool, UseInterpreter, true,                                       \
1158           "Use interpreter for non-compiled methods")                       \
1159                                                                             \
1160   develop(bool, UseFastSignatureHandlers, true,                             \
1161           "Use fast signature handlers for native calls")                   \
1162                                                                             \
1163   product(bool, UseLoopCounter, true,                                       \
1164           "Increment invocation counter on backward branch")                \
1165                                                                             \
1166   product_pd(bool, UseOnStackReplacement,                                   \
1167           "Use on stack replacement, calls runtime if invoc. counter "      \
1168           "overflows in loop")                                              \
1169                                                                             \
1170   notproduct(bool, TraceOnStackReplacement, false,                          \
1171           "Trace on stack replacement")                                     \
1172                                                                             \
1173   product_pd(bool, PreferInterpreterNativeStubs,                            \
1174           "Use always interpreter stubs for native methods invoked via "    \
1175           "interpreter")                                                    \
1176                                                                             \
1177   develop(bool, CountBytecodes, false,                                      \
1178           "Count number of bytecodes executed")                             \
1179                                                                             \
1180   develop(bool, PrintBytecodeHistogram, false,                              \
1181           "Print histogram of the executed bytecodes")                      \
1182                                                                             \
1183   develop(bool, PrintBytecodePairHistogram, false,                          \
1184           "Print histogram of the executed bytecode pairs")                 \
1185                                                                             \
1186   product(bool, PrintSignatureHandlers, false, DIAGNOSTIC,                  \
1187           "Print code generated for native method signature handlers")      \
1188                                                                             \
1189   develop(bool, VerifyOops, false,                                          \
1190           "Do plausibility checks for oops")                                \
1191                                                                             \
1192   develop(bool, CheckUnhandledOops, false,                                  \
1193           "Check for unhandled oops in VM code")                            \
1194                                                                             \
1195   develop(bool, VerifyJNIFields, trueInDebug,                               \
1196           "Verify jfieldIDs for instance fields")                           \
1197                                                                             \
1198   develop(bool, VerifyFPU, false,                                           \
1199           "Verify FPU state (check for NaN's, etc.)")                       \
1200                                                                             \
1201   develop(bool, VerifyActivationFrameSize, false,                           \
1202           "Verify that activation frame didn't become smaller than its "    \
1203           "minimal size")                                                   \
1204                                                                             \
1205   develop(bool, TraceFrequencyInlining, false,                              \
1206           "Trace frequency based inlining")                                 \
1207                                                                             \
1208   develop_pd(bool, InlineIntrinsics,                                        \
1209           "Use intrinsics in Interpreter that can be statically resolved")  \
1210                                                                             \
1211   product_pd(bool, ProfileInterpreter,                                      \
1212           "Profile at the bytecode level during interpretation")            \
1213                                                                             \
1214   develop_pd(bool, ProfileTraps,                                            \
1215           "Profile deoptimization traps at the bytecode level")             \
1216                                                                             \
1217   product(intx, ProfileMaturityPercentage, 20,                              \
1218           "number of method invocations/branches (expressed as % of "       \
1219           "CompileThreshold) before using the method's profile")            \
1220           range(0, 100)                                                     \
1221                                                                             \
1222   product(bool, PrintMethodData, false, DIAGNOSTIC,                         \
1223           "Print the results of +ProfileInterpreter at end of run")         \
1224                                                                             \
1225   develop(bool, VerifyDataPointer, trueInDebug,                             \
1226           "Verify the method data pointer during interpreter profiling")    \
1227                                                                             \
1228   notproduct(bool, CrashGCForDumpingJavaThread, false,                      \
1229           "Manually make GC thread crash then dump java stack trace;  "     \
1230           "Test only")                                                      \
1231                                                                             \
1232   /* compilation */                                                         \
1233   product(bool, UseCompiler, true,                                          \
1234           "Use Just-In-Time compilation")                                   \
1235                                                                             \
1236   develop(intx, CounterHalfLifeTime,    30,                                 \
1237           "Half-life time of invocation counters (in seconds)")             \
1238                                                                             \
1239   product(bool, AlwaysCompileLoopMethods, false,                            \
1240           "When using recompilation, never interpret methods "              \
1241           "containing loops")                                               \
1242                                                                             \
1243   product(int,  AllocatePrefetchStyle, 1,                                   \
1244           "0 = no prefetch, "                                               \
1245           "1 = generate prefetch instructions for each allocation, "        \
1246           "2 = use TLAB watermark to gate allocation prefetch, "            \
1247           "3 = generate one prefetch instruction per cache line")           \
1248           range(0, 3)                                                       \
1249                                                                             \
1250   product(int,  AllocatePrefetchDistance, -1,                               \
1251           "Distance to prefetch ahead of allocation pointer. "              \
1252           "-1: use system-specific value (automatically determined")        \
1253           range(-1, 512)                                                    \
1254                                                                             \
1255   product(int,  AllocatePrefetchLines, 3,                                   \
1256           "Number of lines to prefetch ahead of array allocation pointer")  \
1257           range(1, 64)                                                      \
1258                                                                             \
1259   product(int,  AllocateInstancePrefetchLines, 1,                           \
1260           "Number of lines to prefetch ahead of instance allocation "       \
1261           "pointer")                                                        \
1262           range(1, 64)                                                      \
1263                                                                             \
1264   product(int,  AllocatePrefetchStepSize, 16,                               \
1265           "Step size in bytes of sequential prefetch instructions")         \
1266           range(1, 512)                                                     \
1267           constraint(AllocatePrefetchStepSizeConstraintFunc,AfterMemoryInit)\
1268                                                                             \
1269   product(intx,  AllocatePrefetchInstr, 0,                                  \
1270           "Select instruction to prefetch ahead of allocation pointer")     \
1271           constraint(AllocatePrefetchInstrConstraintFunc, AfterMemoryInit)  \
1272                                                                             \
1273   /* deoptimization */                                                      \
1274   product(bool, TraceDeoptimization, false, DIAGNOSTIC,                     \
1275           "Trace deoptimization")                                           \
1276                                                                             \
1277   develop(bool, PrintDeoptimizationDetails, false,                          \
1278           "Print more information about deoptimization")                    \
1279                                                                             \
1280   develop(bool, DebugDeoptimization, false,                                 \
1281           "Tracing various information while debugging deoptimization")     \
1282                                                                             \
1283   product(double, SelfDestructTimer, 0.0,                                   \
1284           "Will cause VM to terminate after a given time "                  \
1285           "(in fractional minutes) "                                        \
1286           "(0.0 means off)")                                                \
1287           range(0.0, (double)max_intx)                                      \
1288                                                                             \
1289   product(int, MaxJavaStackTraceDepth, 1024,                                \
1290           "The maximum number of lines in the stack trace for Java "        \
1291           "exceptions (0 means all)")                                       \
1292           range(0, max_jint/2)                                              \
1293                                                                             \
1294   /* notice: the max range value here is max_jint, not max_intx  */         \
1295   /* because of overflow issue                                   */         \
1296   product(intx, GuaranteedSafepointInterval, 1000, DIAGNOSTIC,              \
1297           "Guarantee a safepoint (at least) every so many milliseconds "    \
1298           "(0 means none)")                                                 \
1299           range(0, max_jint)                                                \
1300                                                                             \
1301   product(double, SafepointTimeoutDelay, 10000,                             \
1302           "Delay in milliseconds for option SafepointTimeout; "             \
1303           "supports sub-millisecond resolution with fractional values.")    \
1304           range(0, max_jlongDouble LP64_ONLY(/MICROUNITS))                  \
1305                                                                             \
1306   product(bool, UseSystemMemoryBarrier, false,                              \
1307           "Try to enable system memory barrier if supported by OS")         \
1308                                                                             \
1309   product(intx, NmethodSweepActivity, 4,                                    \
1310           "Removes cold nmethods from code cache if > 0. Higher values "    \
1311           "result in more aggressive sweeping")                             \
1312           range(0, 2000)                                                    \
1313                                                                             \
1314   develop(intx, MallocCatchPtr, -1,                                         \
1315           "Hit breakpoint when mallocing/freeing this pointer")             \
1316                                                                             \
1317   develop(int, StackPrintLimit, 100,                                        \
1318           "number of stack frames to print in VM-level stack dump")         \
1319                                                                             \
1320   product(int, ErrorLogPrintCodeLimit, 3, DIAGNOSTIC,                       \
1321           "max number of compiled code units to print in error log")        \
1322           range(0, VMError::max_error_log_print_code)                       \
1323                                                                             \
1324   notproduct(int, MaxElementPrintSize, 256,                                 \
1325           "maximum number of elements to print")                            \
1326                                                                             \
1327   notproduct(intx, MaxSubklassPrintSize, 4,                                 \
1328           "maximum number of subklasses to print when printing klass")      \
1329                                                                             \
1330   develop(intx, MaxForceInlineLevel, 100,                                   \
1331           "maximum number of nested calls that are forced for inlining "    \
1332           "(using CompileCommand or marked w/ @ForceInline)")               \
1333           range(0, max_jint)                                                \
1334                                                                             \
1335   develop(intx, MethodHistogramCutoff, 100,                                 \
1336           "The cutoff value for method invocation histogram (+CountCalls)") \
1337                                                                             \
1338   develop(intx, DontYieldALotInterval,    10,                               \
1339           "Interval between which yields will be dropped (milliseconds)")   \
1340                                                                             \
1341   notproduct(intx, DeoptimizeALotInterval,     5,                           \
1342           "Number of exits until DeoptimizeALot kicks in")                  \
1343                                                                             \
1344   notproduct(intx, ZombieALotInterval,     5,                               \
1345           "Number of exits until ZombieALot kicks in")                      \
1346                                                                             \
1347   product(ccstr, MallocLimit, nullptr, DIAGNOSTIC,                          \
1348           "Limit malloc allocation size from VM. Reaching a limit will "    \
1349           "trigger an action (see flag). This feature requires "            \
1350           "NativeMemoryTracking=summary or NativeMemoryTracking=detail."    \
1351           "Usage:"                                                          \
1352           "\"-XX:MallocLimit=<size>[:<flag>]\" sets a total limit."         \
1353           "\"-XX:MallocLimit=<category>:<size>[:<flag>][,<category>:<size>[:<flag>] ...]\"" \
1354           "sets one or more category-specific limits."                      \
1355           "<flag> defines the action upon reaching the limit:"              \
1356           "\"fatal\": end VM with a fatal error at the allocation site"     \
1357           "\"oom\"  : will mimic a native OOM"                              \
1358           "If <flag> is omitted, \"fatal\" is the default."                 \
1359           "Examples:\n"                                                     \
1360           "-XX:MallocLimit=2g"                                              \
1361           "-XX:MallocLimit=2g:oom"                                          \
1362           "-XX:MallocLimit=compiler:200m:oom,code:100m")                    \
1363                                                                             \
1364   product(intx, TypeProfileWidth, 2,                                        \
1365           "Number of receiver types to record in call/cast profile")        \
1366           range(0, 8)                                                       \
1367                                                                             \
1368   develop(intx, BciProfileWidth,      2,                                    \
1369           "Number of return bci's to record in ret profile")                \
1370                                                                             \
1371   product(intx, PerMethodRecompilationCutoff, 400,                          \
1372           "After recompiling N times, stay in the interpreter (-1=>'Inf')") \
1373           range(-1, max_intx)                                               \
1374                                                                             \
1375   product(intx, PerBytecodeRecompilationCutoff, 200,                        \
1376           "Per-BCI limit on repeated recompilation (-1=>'Inf')")            \
1377           range(-1, max_intx)                                               \
1378                                                                             \
1379   product(intx, PerMethodTrapLimit,  100,                                   \
1380           "Limit on traps (of one kind) in a method (includes inlines)")    \
1381           range(0, max_jint)                                                \
1382                                                                             \
1383   product(intx, PerMethodSpecTrapLimit,  5000, EXPERIMENTAL,                \
1384           "Limit on speculative traps (of one kind) in a method "           \
1385           "(includes inlines)")                                             \
1386           range(0, max_jint)                                                \
1387                                                                             \
1388   product(intx, PerBytecodeTrapLimit,  4,                                   \
1389           "Limit on traps (of one kind) at a particular BCI")               \
1390           range(0, max_jint)                                                \
1391                                                                             \
1392   product(int, SpecTrapLimitExtraEntries,  3, EXPERIMENTAL,                 \
1393           "Extra method data trap entries for speculation")                 \
1394                                                                             \
1395   product(double, InlineFrequencyRatio, 0.25, DIAGNOSTIC,                   \
1396           "Ratio of call site execution to caller method invocation")       \
1397                                                                             \
1398   product(double, MinInlineFrequencyRatio, 0.0085, DIAGNOSTIC,              \
1399           "Minimum ratio of call site execution to caller method"           \
1400           "invocation to be considered for inlining")                       \
1401                                                                             \
1402   develop(intx, InlineThrowCount,    50,                                    \
1403           "Force inlining of interpreted methods that throw this often")    \
1404           range(0, max_jint)                                                \
1405                                                                             \
1406   develop(intx, InlineThrowMaxSize,   200,                                  \
1407           "Force inlining of throwing methods smaller than this")           \
1408           range(0, max_jint)                                                \
1409                                                                             \
1410   product(size_t, MetaspaceSize, NOT_LP64(16 * M) LP64_ONLY(21 * M),        \
1411           "Initial threshold (in bytes) at which a garbage collection "     \
1412           "is done to reduce Metaspace usage")                              \
1413           constraint(MetaspaceSizeConstraintFunc,AfterErgo)                 \
1414                                                                             \
1415   product(size_t, MaxMetaspaceSize, max_uintx,                              \
1416           "Maximum size of Metaspaces (in bytes)")                          \
1417           constraint(MaxMetaspaceSizeConstraintFunc,AfterErgo)              \
1418                                                                             \
1419   product(size_t, CompressedClassSpaceSize, 1*G,                            \
1420           "Maximum size of class area in Metaspace when compressed "        \
1421           "class pointers are used")                                        \
1422           range(1*M, 3*G)                                                   \
1423                                                                             \
1424   develop(size_t, CompressedClassSpaceBaseAddress, 0,                       \
1425           "Force the class space to be allocated at this address or "       \
1426           "fails VM initialization (requires -Xshare=off.")                 \
1427                                                                             \
1428   develop(bool, RandomizeClassSpaceLocation, true,                          \
1429           "Randomize location of class space.")                             \
1430                                                                             \
1431   product(bool, PrintMetaspaceStatisticsAtExit, false, DIAGNOSTIC,          \
1432           "Print metaspace statistics upon VM exit.")                       \
1433                                                                             \
1434   develop(bool, MetaspaceGuardAllocations, false,                           \
1435           "Metapace allocations are guarded.")                              \
1436                                                                             \
1437   product(uintx, MinHeapFreeRatio, 40, MANAGEABLE,                          \
1438           "The minimum percentage of heap free after GC to avoid expansion."\
1439           " For most GCs this applies to the old generation. In G1 and"     \
1440           " ParallelGC it applies to the whole heap.")                      \
1441           range(0, 100)                                                     \
1442           constraint(MinHeapFreeRatioConstraintFunc,AfterErgo)              \
1443                                                                             \
1444   product(uintx, MaxHeapFreeRatio, 70, MANAGEABLE,                          \
1445           "The maximum percentage of heap free after GC to avoid shrinking."\
1446           " For most GCs this applies to the old generation. In G1 and"     \
1447           " ParallelGC it applies to the whole heap.")                      \
1448           range(0, 100)                                                     \
1449           constraint(MaxHeapFreeRatioConstraintFunc,AfterErgo)              \
1450                                                                             \
1451   product(bool, ShrinkHeapInSteps, true,                                    \
1452           "When disabled, informs the GC to shrink the java heap directly"  \
1453           " to the target size at the next full GC rather than requiring"   \
1454           " smaller steps during multiple full GCs.")                       \
1455                                                                             \
1456   product(intx, SoftRefLRUPolicyMSPerMB, 1000,                              \
1457           "Number of milliseconds per MB of free space in the heap")        \
1458           range(0, max_intx)                                                \
1459           constraint(SoftRefLRUPolicyMSPerMBConstraintFunc,AfterMemoryInit) \
1460                                                                             \
1461   product(size_t, MinHeapDeltaBytes, ScaleForWordSize(128*K),               \
1462           "The minimum change in heap space due to GC (in bytes)")          \
1463           range(0, max_uintx)                                               \
1464                                                                             \
1465   product(size_t, MinMetaspaceExpansion, ScaleForWordSize(256*K),           \
1466           "The minimum expansion of Metaspace (in bytes)")                  \
1467           range(0, max_uintx)                                               \
1468                                                                             \
1469   product(uint, MaxMetaspaceFreeRatio,    70,                               \
1470           "The maximum percentage of Metaspace free after GC to avoid "     \
1471           "shrinking")                                                      \
1472           range(0, 100)                                                     \
1473           constraint(MaxMetaspaceFreeRatioConstraintFunc,AfterErgo)         \
1474                                                                             \
1475   product(uint, MinMetaspaceFreeRatio,    40,                               \
1476           "The minimum percentage of Metaspace free after GC to avoid "     \
1477           "expansion")                                                      \
1478           range(0, 99)                                                      \
1479           constraint(MinMetaspaceFreeRatioConstraintFunc,AfterErgo)         \
1480                                                                             \
1481   product(size_t, MaxMetaspaceExpansion, ScaleForWordSize(4*M),             \
1482           "The maximum expansion of Metaspace without full GC (in bytes)")  \
1483           range(0, max_uintx)                                               \
1484                                                                             \
1485   /* stack parameters */                                                    \
1486   product_pd(intx, StackYellowPages,                                        \
1487           "Number of yellow zone (recoverable overflows) pages of size "    \
1488           "4KB. If pages are bigger yellow zone is aligned up.")            \
1489           range(MIN_STACK_YELLOW_PAGES, (DEFAULT_STACK_YELLOW_PAGES+5))     \
1490                                                                             \
1491   product_pd(intx, StackRedPages,                                           \
1492           "Number of red zone (unrecoverable overflows) pages of size "     \
1493           "4KB. If pages are bigger red zone is aligned up.")               \
1494           range(MIN_STACK_RED_PAGES, (DEFAULT_STACK_RED_PAGES+2))           \
1495                                                                             \
1496   product_pd(intx, StackReservedPages,                                      \
1497           "Number of reserved zone (reserved to annotated methods) pages"   \
1498           " of size 4KB. If pages are bigger reserved zone is aligned up.") \
1499           range(MIN_STACK_RESERVED_PAGES, (DEFAULT_STACK_RESERVED_PAGES+10))\
1500                                                                             \
1501   product(bool, RestrictReservedStack, true,                                \
1502           "Restrict @ReservedStackAccess to trusted classes")               \
1503                                                                             \
1504   /* greater stack shadow pages can't generate instruction to bang stack */ \
1505   product_pd(intx, StackShadowPages,                                        \
1506           "Number of shadow zone (for overflow checking) pages of size "    \
1507           "4KB. If pages are bigger shadow zone is aligned up. "            \
1508           "This should exceed the depth of the VM and native call stack.")  \
1509           range(MIN_STACK_SHADOW_PAGES, (DEFAULT_STACK_SHADOW_PAGES+30))    \
1510                                                                             \
1511   product_pd(intx, ThreadStackSize,                                         \
1512           "Thread Stack Size (in Kbytes)")                                  \
1513           range(0, 1 * M)                                                   \
1514                                                                             \
1515   product_pd(intx, VMThreadStackSize,                                       \
1516           "Non-Java Thread Stack Size (in Kbytes)")                         \
1517           range(0, max_intx/(1 * K))                                        \
1518                                                                             \
1519   product_pd(intx, CompilerThreadStackSize,                                 \
1520           "Compiler Thread Stack Size (in Kbytes)")                         \
1521           range(0, max_intx/(1 * K))                                        \
1522                                                                             \
1523   develop_pd(size_t, JVMInvokeMethodSlack,                                  \
1524           "Stack space (bytes) required for JVM_InvokeMethod to complete")  \
1525                                                                             \
1526   /* code cache parameters                                    */            \
1527   product_pd(uintx, CodeCacheSegmentSize, EXPERIMENTAL,                     \
1528           "Code cache segment size (in bytes) - smallest unit of "          \
1529           "allocation")                                                     \
1530           range(1, 1024)                                                    \
1531           constraint(CodeCacheSegmentSizeConstraintFunc, AfterErgo)         \
1532                                                                             \
1533   product_pd(intx, CodeEntryAlignment, EXPERIMENTAL,                        \
1534           "Code entry alignment for generated code (in bytes)")             \
1535           constraint(CodeEntryAlignmentConstraintFunc, AfterErgo)           \
1536                                                                             \
1537   product_pd(intx, OptoLoopAlignment,                                       \
1538           "Align inner loops to zero relative to this modulus")             \
1539           range(1, 128)                                                     \
1540           constraint(OptoLoopAlignmentConstraintFunc, AfterErgo)            \
1541                                                                             \
1542   product_pd(uintx, InitialCodeCacheSize,                                   \
1543           "Initial code cache size (in bytes)")                             \
1544           constraint(VMPageSizeConstraintFunc, AtParse)                     \
1545                                                                             \
1546   develop_pd(uintx, CodeCacheMinimumUseSpace,                               \
1547           "Minimum code cache size (in bytes) required to start VM.")       \
1548           range(0, max_uintx)                                               \
1549                                                                             \
1550   product(bool, SegmentedCodeCache, false,                                  \
1551           "Use a segmented code cache")                                     \
1552                                                                             \
1553   product_pd(uintx, ReservedCodeCacheSize,                                  \
1554           "Reserved code cache size (in bytes) - maximum code cache size")  \
1555           constraint(VMPageSizeConstraintFunc, AtParse)                     \
1556                                                                             \
1557   product_pd(uintx, NonProfiledCodeHeapSize,                                \
1558           "Size of code heap with non-profiled methods (in bytes)")         \
1559           range(0, max_uintx)                                               \
1560                                                                             \
1561   product_pd(uintx, ProfiledCodeHeapSize,                                   \
1562           "Size of code heap with profiled methods (in bytes)")             \
1563           range(0, max_uintx)                                               \
1564                                                                             \
1565   product_pd(uintx, NonNMethodCodeHeapSize,                                 \
1566           "Size of code heap with non-nmethods (in bytes)")                 \
1567           constraint(VMPageSizeConstraintFunc, AtParse)                     \
1568                                                                             \
1569   product_pd(uintx, CodeCacheExpansionSize,                                 \
1570           "Code cache expansion size (in bytes)")                           \
1571           range(32*K, max_uintx)                                            \
1572                                                                             \
1573   product_pd(uintx, CodeCacheMinBlockLength, DIAGNOSTIC,                    \
1574           "Minimum number of segments in a code cache block")               \
1575           range(1, 100)                                                     \
1576                                                                             \
1577   notproduct(bool, ExitOnFullCodeCache, false,                              \
1578           "Exit the VM if we fill the code cache")                          \
1579                                                                             \
1580   product(bool, UseCodeCacheFlushing, true,                                 \
1581           "Remove cold/old nmethods from the code cache")                   \
1582                                                                             \
1583   product(double, SweeperThreshold, 15.0,                                   \
1584           "Threshold when a code cache unloading GC is invoked."            \
1585           "Value is percentage of ReservedCodeCacheSize.")                  \
1586           range(0.0, 100.0)                                                 \
1587                                                                             \
1588   product(uintx, StartAggressiveSweepingAt, 10,                             \
1589           "Start aggressive sweeping if X[%] of the code cache is free."    \
1590           "Segmented code cache: X[%] of the non-profiled heap."            \
1591           "Non-segmented code cache: X[%] of the total code cache")         \
1592           range(0, 100)                                                     \
1593                                                                             \
1594   /* interpreter debugging */                                               \
1595   develop(intx, BinarySwitchThreshold, 5,                                   \
1596           "Minimal number of lookupswitch entries for rewriting to binary " \
1597           "switch")                                                         \
1598                                                                             \
1599   develop(intx, StopInterpreterAt, 0,                                       \
1600           "Stop interpreter execution at specified bytecode number")        \
1601                                                                             \
1602   develop(intx, TraceBytecodesAt, 0,                                        \
1603           "Trace bytecodes starting with specified bytecode number")        \
1604                                                                             \
1605   develop(intx, TraceBytecodesStopAt, 0,                                    \
1606           "Stop bytecode tracing at the specified bytecode number")         \
1607                                                                             \
1608   /* Priorities */                                                          \
1609   product_pd(bool, UseThreadPriorities,  "Use native thread priorities")    \
1610                                                                             \
1611   product(int, ThreadPriorityPolicy, 0,                                     \
1612           "0 : Normal.                                                     "\
1613           "    VM chooses priorities that are appropriate for normal       "\
1614           "    applications.                                               "\
1615           "    On Windows applications are allowed to use higher native    "\
1616           "    priorities. However, with ThreadPriorityPolicy=0, VM will   "\
1617           "    not use the highest possible native priority,               "\
1618           "    THREAD_PRIORITY_TIME_CRITICAL, as it may interfere with     "\
1619           "    system threads. On Linux thread priorities are ignored      "\
1620           "    because the OS does not support static priority in          "\
1621           "    SCHED_OTHER scheduling class which is the only choice for   "\
1622           "    non-root, non-realtime applications.                        "\
1623           "1 : Aggressive.                                                 "\
1624           "    Java thread priorities map over to the entire range of      "\
1625           "    native thread priorities. Higher Java thread priorities map "\
1626           "    to higher native thread priorities. This policy should be   "\
1627           "    used with care, as sometimes it can cause performance       "\
1628           "    degradation in the application and/or the entire system. On "\
1629           "    Linux/BSD/macOS this policy requires root privilege or an   "\
1630           "    extended capability.")                                       \
1631           range(0, 1)                                                       \
1632                                                                             \
1633   product(bool, ThreadPriorityVerbose, false,                               \
1634           "Print priority changes")                                         \
1635                                                                             \
1636   product(int, CompilerThreadPriority, -1,                                  \
1637           "The native priority at which compiler threads should run "       \
1638           "(-1 means no change)")                                           \
1639           range(min_jint, max_jint)                                         \
1640                                                                             \
1641   product(int, VMThreadPriority, -1,                                        \
1642           "The native priority at which the VM thread should run "          \
1643           "(-1 means no change)")                                           \
1644           range(-1, 127)                                                    \
1645                                                                             \
1646   product(int, JavaPriority1_To_OSPriority, -1,                             \
1647           "Map Java priorities to OS priorities")                           \
1648           range(-1, 127)                                                    \
1649                                                                             \
1650   product(int, JavaPriority2_To_OSPriority, -1,                             \
1651           "Map Java priorities to OS priorities")                           \
1652           range(-1, 127)                                                    \
1653                                                                             \
1654   product(int, JavaPriority3_To_OSPriority, -1,                             \
1655           "Map Java priorities to OS priorities")                           \
1656           range(-1, 127)                                                    \
1657                                                                             \
1658   product(int, JavaPriority4_To_OSPriority, -1,                             \
1659           "Map Java priorities to OS priorities")                           \
1660           range(-1, 127)                                                    \
1661                                                                             \
1662   product(int, JavaPriority5_To_OSPriority, -1,                             \
1663           "Map Java priorities to OS priorities")                           \
1664           range(-1, 127)                                                    \
1665                                                                             \
1666   product(int, JavaPriority6_To_OSPriority, -1,                             \
1667           "Map Java priorities to OS priorities")                           \
1668           range(-1, 127)                                                    \
1669                                                                             \
1670   product(int, JavaPriority7_To_OSPriority, -1,                             \
1671           "Map Java priorities to OS priorities")                           \
1672           range(-1, 127)                                                    \
1673                                                                             \
1674   product(int, JavaPriority8_To_OSPriority, -1,                             \
1675           "Map Java priorities to OS priorities")                           \
1676           range(-1, 127)                                                    \
1677                                                                             \
1678   product(int, JavaPriority9_To_OSPriority, -1,                             \
1679           "Map Java priorities to OS priorities")                           \
1680           range(-1, 127)                                                    \
1681                                                                             \
1682   product(int, JavaPriority10_To_OSPriority,-1,                             \
1683           "Map Java priorities to OS priorities")                           \
1684           range(-1, 127)                                                    \
1685                                                                             \
1686   product(bool, UseCriticalJavaThreadPriority, false, EXPERIMENTAL,         \
1687           "Java thread priority 10 maps to critical scheduling priority")   \
1688                                                                             \
1689   product(bool, UseCriticalCompilerThreadPriority, false, EXPERIMENTAL,     \
1690           "Compiler thread(s) run at critical scheduling priority")         \
1691                                                                             \
1692   develop(intx, NewCodeParameter,      0,                                   \
1693           "Testing Only: Create a dedicated integer parameter before "      \
1694           "putback")                                                        \
1695                                                                             \
1696   /* new oopmap storage allocation */                                       \
1697   develop(intx, MinOopMapAllocation,     8,                                 \
1698           "Minimum number of OopMap entries in an OopMapSet")               \
1699                                                                             \
1700   /* recompilation */                                                       \
1701   product_pd(intx, CompileThreshold,                                        \
1702           "number of interpreted method invocations before (re-)compiling") \
1703           constraint(CompileThresholdConstraintFunc, AfterErgo)             \
1704                                                                             \
1705   product_pd(bool, TieredCompilation,                                       \
1706           "Enable tiered compilation")                                      \
1707                                                                             \
1708   /* Properties for Java libraries  */                                      \
1709                                                                             \
1710   product(uint64_t, MaxDirectMemorySize, 0,                                 \
1711           "Maximum total size of NIO direct-buffer allocations. "           \
1712           "Ignored if not explicitly set.")                                 \
1713           range(0, max_jlong)                                               \
1714                                                                             \
1715   /* Flags used for temporary code during development  */                   \
1716                                                                             \
1717   product(bool, UseNewCode, false, DIAGNOSTIC,                              \
1718           "Testing Only: Use the new version while testing")                \
1719                                                                             \
1720   product(bool, UseNewCode2, false, DIAGNOSTIC,                             \
1721           "Testing Only: Use the new version while testing")                \
1722                                                                             \
1723   product(bool, UseNewCode3, false, DIAGNOSTIC,                             \
1724           "Testing Only: Use the new version while testing")                \
1725                                                                             \
1726   notproduct(bool, UseDebuggerErgo, false,                                  \
1727           "Debugging Only: Adjust the VM to be more debugger-friendly. "    \
1728           "Turns on the other UseDebuggerErgo* flags")                      \
1729                                                                             \
1730   notproduct(bool, UseDebuggerErgo1, false,                                 \
1731           "Debugging Only: Enable workarounds for debugger induced "        \
1732           "os::processor_id() >= os::processor_count() problems")           \
1733                                                                             \
1734   notproduct(bool, UseDebuggerErgo2, false,                                 \
1735           "Debugging Only: Limit the number of spawned JVM threads")        \
1736                                                                             \
1737   notproduct(bool, EnableJVMTIStackDepthAsserts, true,                      \
1738           "Enable JVMTI asserts related to stack depth checks")             \
1739                                                                             \
1740   /* flags for performance data collection */                               \
1741                                                                             \
1742   product(bool, UsePerfData, true,                                          \
1743           "Flag to disable jvmstat instrumentation for performance testing "\
1744           "and problem isolation purposes")                                 \
1745                                                                             \
1746   product(bool, PerfDataSaveToFile, false,                                  \
1747           "Save PerfData memory to hsperfdata_<pid> file on exit")          \
1748                                                                             \
1749   product(ccstr, PerfDataSaveFile, nullptr,                                 \
1750           "Save PerfData memory to the specified absolute pathname. "       \
1751           "The string %p in the file name (if present) "                    \
1752           "will be replaced by pid")                                        \
1753                                                                             \
1754   product(int, PerfDataSamplingInterval, 50,                                \
1755           "Data sampling interval (in milliseconds)")                       \
1756           range(PeriodicTask::min_interval, max_jint)                       \
1757           constraint(PerfDataSamplingIntervalFunc, AfterErgo)               \
1758                                                                             \
1759   product(bool, PerfDisableSharedMem, false,                                \
1760           "Store performance data in standard memory")                      \
1761                                                                             \
1762   product(int, PerfDataMemorySize, 32*K,                                    \
1763           "Size of performance data memory region. Will be rounded "        \
1764           "up to a multiple of the native os page size.")                   \
1765           range(128, 32*64*K)                                               \
1766                                                                             \
1767   product(int, PerfMaxStringConstLength, 1024,                              \
1768           "Maximum PerfStringConstant string length before truncation")     \
1769           range(32, 32*K)                                                   \
1770                                                                             \
1771   product(bool, PerfAllowAtExitRegistration, false,                         \
1772           "Allow registration of atexit() methods")                         \
1773                                                                             \
1774   product(bool, PerfBypassFileSystemCheck, false,                           \
1775           "Bypass Win32 file system criteria checks (Windows Only)")        \
1776                                                                             \
1777   product(int, UnguardOnExecutionViolation, 0,                              \
1778           "Unguard page and retry on no-execute fault (Win32 only) "        \
1779           "0=off, 1=conservative, 2=aggressive")                            \
1780           range(0, 2)                                                       \
1781                                                                             \
1782   /* Serviceability Support */                                              \
1783                                                                             \
1784   product(bool, ManagementServer, false,                                    \
1785           "Create JMX Management Server")                                   \
1786                                                                             \
1787   product(bool, DisableAttachMechanism, false,                              \
1788           "Disable mechanism that allows tools to attach to this VM")       \
1789                                                                             \
1790   product(bool, StartAttachListener, false,                                 \
1791           "Always start Attach Listener at VM startup")                     \
1792                                                                             \
1793   product(bool, EnableDynamicAgentLoading, true,                            \
1794           "Allow tools to load agents with the attach mechanism")           \
1795                                                                             \
1796   product(bool, PrintConcurrentLocks, false, MANAGEABLE,                    \
1797           "Print java.util.concurrent locks in thread dump")                \
1798                                                                             \
1799   product(bool, PrintMethodHandleStubs, false, DIAGNOSTIC,                  \
1800           "Print generated stub code for method handles")                   \
1801                                                                             \
1802   product(bool, VerifyMethodHandles, trueInDebug, DIAGNOSTIC,               \
1803           "perform extra checks when constructing method handles")          \
1804                                                                             \
1805   product(bool, ShowHiddenFrames, false, DIAGNOSTIC,                        \
1806           "show method handle implementation frames (usually hidden)")      \
1807                                                                             \
1808   product(bool, ShowCarrierFrames, false, DIAGNOSTIC,                       \
1809           "show virtual threads' carrier frames in exceptions")             \
1810                                                                             \
1811   product(bool, TrustFinalNonStaticFields, false, EXPERIMENTAL,             \
1812           "trust final non-static declarations for constant folding")       \
1813                                                                             \
1814   product(bool, FoldStableValues, true, DIAGNOSTIC,                         \
1815           "Optimize loads from stable fields (marked w/ @Stable)")          \
1816                                                                             \
1817   product(int, UseBootstrapCallInfo, 1, DIAGNOSTIC,                         \
1818           "0: when resolving InDy or ConDy, force all BSM arguments to be " \
1819           "resolved before the bootstrap method is called; 1: when a BSM "  \
1820           "that may accept a BootstrapCallInfo is detected, use that API "  \
1821           "to pass BSM arguments, which allows the BSM to delay their "     \
1822           "resolution; 2+: stress test the BCI API by calling more BSMs "   \
1823           "via that API, instead of with the eagerly-resolved array.")      \
1824                                                                             \
1825   product(bool, PauseAtStartup,      false, DIAGNOSTIC,                     \
1826           "Causes the VM to pause at startup time and wait for the pause "  \
1827           "file to be removed (default: ./vm.paused.<pid>)")                \
1828                                                                             \
1829   product(ccstr, PauseAtStartupFile, nullptr, DIAGNOSTIC,                      \
1830           "The file to create and for whose removal to await when pausing " \
1831           "at startup. (default: ./vm.paused.<pid>)")                       \
1832                                                                             \
1833   product(bool, PauseAtExit, false, DIAGNOSTIC,                             \
1834           "Pause and wait for keypress on exit if a debugger is attached")  \
1835                                                                             \
1836   product(bool, DTraceMethodProbes, false,                                  \
1837           "Enable dtrace tool probes for method-entry and method-exit")     \
1838                                                                             \
1839   product(bool, DTraceAllocProbes, false,                                   \
1840           "Enable dtrace tool probes for object allocation")                \
1841                                                                             \
1842   product(bool, DTraceMonitorProbes, false,                                 \
1843           "Enable dtrace tool probes for monitor events")                   \
1844                                                                             \
1845   product(bool, RelaxAccessControlCheck, false,                             \
1846           "Relax the access control checks in the verifier")                \
1847                                                                             \
1848   product(uintx, StringTableSize, defaultStringTableSize,                   \
1849           "Number of buckets in the interned String table "                 \
1850           "(will be rounded to nearest higher power of 2)")                 \
1851           range(minimumStringTableSize, 16777216ul /* 2^24 */)              \
1852                                                                             \
1853   product(uintx, SymbolTableSize, defaultSymbolTableSize, EXPERIMENTAL,     \
1854           "Number of buckets in the JVM internal Symbol table")             \
1855           range(minimumSymbolTableSize, 16777216ul /* 2^24 */)              \
1856                                                                             \
1857   product(bool, UseStringDeduplication, false,                              \
1858           "Use string deduplication")                                       \
1859                                                                             \
1860   product(uint, StringDeduplicationAgeThreshold, 3,                         \
1861           "A string must reach this age (or be promoted to an old region) " \
1862           "to be considered for deduplication")                             \
1863           range(1, markWord::max_age)                                       \
1864                                                                             \
1865   product(size_t, StringDeduplicationInitialTableSize, 500, EXPERIMENTAL,   \
1866           "Approximate initial number of buckets in the table")             \
1867           range(1, 1 * G)                                                   \
1868                                                                             \
1869   product(double, StringDeduplicationGrowTableLoad, 14.0, EXPERIMENTAL,     \
1870           "Entries per bucket above which the table should be expanded")    \
1871           range(0.1, 1000.0)                                                \
1872                                                                             \
1873   product(double, StringDeduplicationShrinkTableLoad, 1.0, EXPERIMENTAL,    \
1874           "Entries per bucket below which the table should be shrunk")      \
1875           range(0.01, 100.0)                                                \
1876                                                                             \
1877   product(double, StringDeduplicationTargetTableLoad, 7.0, EXPERIMENTAL,    \
1878           "Desired entries per bucket when resizing the table")             \
1879           range(0.01, 1000.0)                                               \
1880                                                                             \
1881   product(size_t, StringDeduplicationCleanupDeadMinimum, 100, EXPERIMENTAL, \
1882           "Minimum number of dead table entries for cleaning the table")    \
1883                                                                             \
1884   product(int, StringDeduplicationCleanupDeadPercent, 5, EXPERIMENTAL,      \
1885           "Minimum percentage of dead table entries for cleaning the table") \
1886           range(1, 100)                                                     \
1887                                                                             \
1888   product(bool, StringDeduplicationResizeALot, false, DIAGNOSTIC,           \
1889           "Force more frequent table resizing")                             \
1890                                                                             \
1891   product(uint64_t, StringDeduplicationHashSeed, 0, DIAGNOSTIC,             \
1892           "Seed for the table hashing function; 0 requests computed seed")  \
1893                                                                             \
1894   product(bool, WhiteBoxAPI, false, DIAGNOSTIC,                             \
1895           "Enable internal testing APIs")                                   \
1896                                                                             \
1897   product(bool, AlwaysAtomicAccesses, false, EXPERIMENTAL,                  \
1898           "Accesses to all variables should always be atomic")              \
1899                                                                             \
1900   product(bool, UseUnalignedAccesses, false, DIAGNOSTIC,                    \
1901           "Use unaligned memory accesses in Unsafe")                        \
1902                                                                             \
1903   product_pd(bool, PreserveFramePointer,                                    \
1904              "Use the FP register for holding the frame pointer "           \
1905              "and not as a general purpose register.")                      \
1906                                                                             \
1907   product(size_t, AsyncLogBufferSize, 2*M,                                  \
1908           "Memory budget (in bytes) for the buffer of Asynchronous "        \
1909           "Logging (-Xlog:async).")                                         \
1910           range(100*K, 50*M)                                                \
1911                                                                             \
1912   product(bool, CheckIntrinsics, true, DIAGNOSTIC,                          \
1913              "When a class C is loaded, check that "                        \
1914              "(1) all intrinsics defined by the VM for class C are present "\
1915              "in the loaded class file and are marked with the "            \
1916              "@IntrinsicCandidate annotation, that "                        \
1917              "(2) there is an intrinsic registered for all loaded methods " \
1918              "that are annotated with the @IntrinsicCandidate annotation, " \
1919              "and that "                                                    \
1920              "(3) no orphan methods exist for class C (i.e., methods for "  \
1921              "which the VM declares an intrinsic but that are not declared "\
1922              "in the loaded class C. "                                      \
1923              "Check (3) is available only in debug builds.")                \
1924                                                                             \
1925   product_pd(intx, InitArrayShortSize, DIAGNOSTIC,                          \
1926           "Threshold small size (in bytes) for clearing arrays. "           \
1927           "Anything this size or smaller may get converted to discrete "    \
1928           "scalar stores.")                                                 \
1929           range(0, max_intx)                                                \
1930           constraint(InitArrayShortSizeConstraintFunc, AfterErgo)           \
1931                                                                             \
1932   product(ccstr, AllocateHeapAt, nullptr,                                   \
1933           "Path to the directory where a temporary file will be created "   \
1934           "to use as the backing store for Java Heap.")                     \
1935                                                                             \
1936   product_pd(bool, VMContinuations, EXPERIMENTAL,                           \
1937           "Enable VM continuations support")                                \
1938                                                                             \
1939   develop(bool, LoomDeoptAfterThaw, false,                                  \
1940           "Deopt stack after thaw")                                         \
1941                                                                             \
1942   develop(bool, LoomVerifyAfterThaw, false,                                 \
1943           "Verify stack after thaw")                                        \
1944                                                                             \
1945   develop(bool, VerifyContinuations, false,                                 \
1946           "Verify continuation consistency")                                \
1947                                                                             \
1948   develop(bool, UseContinuationFastPath, true,                              \
1949           "Use fast-path frame walking in continuations")                   \
1950                                                                             \
1951   develop(int, VerifyMetaspaceInterval, DEBUG_ONLY(500) NOT_DEBUG(0),       \
1952                "Run periodic metaspace verifications (0 - none, "           \
1953                "1 - always, >1 every nth interval)")                        \
1954                                                                             \
1955   product(bool, ShowRegistersOnAssert, true, DIAGNOSTIC,                    \
1956           "On internal errors, include registers in error report.")         \
1957                                                                             \
1958   product(bool, UseSwitchProfiling, true, DIAGNOSTIC,                       \
1959           "leverage profiling for table/lookup switch")                     \
1960                                                                             \
1961   develop(bool, TraceMemoryWriteback, false,                                \
1962           "Trace memory writeback operations")                              \
1963                                                                             \
1964   JFR_ONLY(product(bool, FlightRecorder, false,                             \
1965           "(Deprecated) Enable Flight Recorder"))                           \
1966                                                                             \
1967   JFR_ONLY(product(ccstr, FlightRecorderOptions, nullptr,                   \
1968           "Flight Recorder options"))                                       \
1969                                                                             \
1970   JFR_ONLY(product(ccstr, StartFlightRecording, nullptr,                    \
1971           "Start flight recording with options"))                           \
1972                                                                             \
1973   product(bool, UseFastUnorderedTimeStamps, false, EXPERIMENTAL,            \
1974           "Use platform unstable time where supported for timestamps only") \
1975                                                                             \
1976   product(bool, UseEmptySlotsInSupers, true,                                \
1977                 "Allow allocating fields in empty slots of super-classes")  \
1978                                                                             \
1979   product(bool, DeoptimizeNMethodBarriersALot, false, DIAGNOSTIC,           \
1980                 "Make nmethod barriers deoptimise a lot.")                  \
1981                                                                             \
1982   develop(bool, VerifyCrossModifyFence,                                     \
1983           false AARCH64_ONLY(DEBUG_ONLY(||true)),                           \
1984              "Mark all threads after a safepoint, and clear on a modify "   \
1985              "fence. Add cleanliness checks.")                              \
1986                                                                             \
1987   product(int, LockingMode, LM_LEGACY,                                      \
1988           "Select locking mode: "                                           \
1989           "0: monitors only (LM_MONITOR), "                                 \
1990           "1: monitors & legacy stack-locking (LM_LEGACY, default), "       \
1991           "2: monitors & new lightweight locking (LM_LIGHTWEIGHT)")         \
1992           range(0, 2)                                                       \
1993                                                                             \
1994   product(uint, TrimNativeHeapInterval, 0,                                  \
1995           "Interval, in ms, at which the JVM will trim the native heap if " \
1996           "the platform supports that. Lower values will reclaim memory "   \
1997           "more eagerly at the cost of higher overhead. A value of 0 "      \
1998           "(default) disables native heap trimming.")                       \
1999           range(0, UINT_MAX)                                                \
2000                                                                             \
2001   develop(bool, SimulateFullAddressSpace, false,                            \
2002           "Simulates a very populated, fragmented address space; no "       \
2003           "targeted reservations will succeed.")                            \
2004                                                                             \
2005   product(bool, ProfileExceptionHandlers, true,                             \
2006           "Profile exception handlers")                                     \
2007                                                                             \
2008   product(bool, AlwaysRecordEvolDependencies, true, EXPERIMENTAL,           \
2009                 "Unconditionally record nmethod dependencies on class "     \
2010                 "rewriting/transformation independently of the JVMTI "      \
2011                 "can_{retransform/redefine}_classes capabilities.")         \
2012 
2013 // end of RUNTIME_FLAGS
2014 
2015 DECLARE_FLAGS(LP64_RUNTIME_FLAGS)
2016 DECLARE_ARCH_FLAGS(ARCH_FLAGS)
2017 DECLARE_FLAGS(RUNTIME_FLAGS)
2018 DECLARE_FLAGS(RUNTIME_OS_FLAGS)
2019 
2020 #endif // SHARE_RUNTIME_GLOBALS_HPP