1 /*
   2  * Copyright (c) 1997, 2023, 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_UTILITIES_GLOBALDEFINITIONS_HPP
  26 #define SHARE_UTILITIES_GLOBALDEFINITIONS_HPP
  27 
  28 #include "utilities/attributeNoreturn.hpp"
  29 #include "utilities/compilerWarnings.hpp"
  30 #include "utilities/debug.hpp"
  31 #include "utilities/macros.hpp"
  32 
  33 // Get constants like JVM_T_CHAR and JVM_SIGNATURE_INT, before pulling in <jvm.h>.
  34 #include "classfile_constants.h"
  35 
  36 #include COMPILER_HEADER(utilities/globalDefinitions)
  37 
  38 #include <cstddef>
  39 #include <cstdint>
  40 #include <type_traits>
  41 
  42 class oopDesc;
  43 
  44 // Defaults for macros that might be defined per compiler.
  45 #ifndef NOINLINE
  46 #define NOINLINE
  47 #endif
  48 #ifndef ALWAYSINLINE
  49 #define ALWAYSINLINE inline
  50 #endif
  51 
  52 #ifndef ATTRIBUTE_ALIGNED
  53 #define ATTRIBUTE_ALIGNED(x)
  54 #endif
  55 
  56 #ifndef ATTRIBUTE_FLATTEN
  57 #define ATTRIBUTE_FLATTEN
  58 #endif
  59 
  60 // These are #defines to selectively turn on/off the Print(Opto)Assembly
  61 // capabilities. Choices should be led by a tradeoff between
  62 // code size and improved supportability.
  63 // if PRINT_ASSEMBLY then PRINT_ABSTRACT_ASSEMBLY must be true as well
  64 // to have a fallback in case hsdis is not available.
  65 #if defined(PRODUCT)
  66   #define SUPPORT_ABSTRACT_ASSEMBLY
  67   #define SUPPORT_ASSEMBLY
  68   #undef  SUPPORT_OPTO_ASSEMBLY      // Can't activate. In PRODUCT, many dump methods are missing.
  69   #undef  SUPPORT_DATA_STRUCTS       // Of limited use. In PRODUCT, many print methods are empty.
  70 #else
  71   #define SUPPORT_ABSTRACT_ASSEMBLY
  72   #define SUPPORT_ASSEMBLY
  73   #define SUPPORT_OPTO_ASSEMBLY
  74   #define SUPPORT_DATA_STRUCTS
  75 #endif
  76 #if defined(SUPPORT_ASSEMBLY) && !defined(SUPPORT_ABSTRACT_ASSEMBLY)
  77   #define SUPPORT_ABSTRACT_ASSEMBLY
  78 #endif
  79 
  80 // This file holds all globally used constants & types, class (forward)
  81 // declarations and a few frequently used utility functions.
  82 
  83 // Declare the named class to be noncopyable.  This macro must be followed by
  84 // a semi-colon.  The macro provides deleted declarations for the class's copy
  85 // constructor and assignment operator.  Because these operations are deleted,
  86 // they cannot be defined and potential callers will fail to compile.
  87 #define NONCOPYABLE(C) C(C const&) = delete; C& operator=(C const&) = delete /* next token must be ; */
  88 
  89 
  90 //----------------------------------------------------------------------------------------------------
  91 // Printf-style formatters for fixed- and variable-width types as pointers and
  92 // integers.  These are derived from the definitions in inttypes.h.  If the platform
  93 // doesn't provide appropriate definitions, they should be provided in
  94 // the compiler-specific definitions file (e.g., globalDefinitions_gcc.hpp)
  95 
  96 // Guide to the suffixes used in the format specifiers for integers:
  97 //        - print the decimal value:                   745565
  98 //  _X    - print as hexadecimal, without leading 0s: 0x12345
  99 //  _X_0  - print as hexadecimal, with leading 0s: 0x00012345
 100 //  _W(w) - prints w sized string with the given value right
 101 //          adjusted. Use -w to print left adjusted.
 102 //
 103 // Note that the PTR format specifiers print using 0x with leading zeros,
 104 // just like the _X_0 version for integers.
 105 
 106 // Format 8-bit quantities.
 107 #define INT8_FORMAT_X_0          "0x%02"      PRIx8
 108 #define UINT8_FORMAT_X_0         "0x%02"      PRIx8
 109 
 110 // Format 16-bit quantities.
 111 #define INT16_FORMAT_X_0         "0x%04"      PRIx16
 112 #define UINT16_FORMAT_X_0        "0x%04"      PRIx16
 113 
 114 // Format 32-bit quantities.
 115 #define INT32_FORMAT             "%"          PRId32
 116 #define INT32_FORMAT_X           "0x%"        PRIx32
 117 #define INT32_FORMAT_X_0         "0x%08"      PRIx32
 118 #define INT32_FORMAT_W(width)    "%"   #width PRId32
 119 #define UINT32_FORMAT            "%"          PRIu32
 120 #define UINT32_FORMAT_X          "0x%"        PRIx32
 121 #define UINT32_FORMAT_X_0        "0x%08"      PRIx32
 122 #define UINT32_FORMAT_W(width)   "%"   #width PRIu32
 123 
 124 // Format 64-bit quantities.
 125 #define INT64_FORMAT             "%"          PRId64
 126 #define INT64_PLUS_FORMAT        "%+"         PRId64
 127 #define INT64_FORMAT_X           "0x%"        PRIx64
 128 #define INT64_FORMAT_X_0         "0x%016"     PRIx64
 129 #define INT64_FORMAT_W(width)    "%"   #width PRId64
 130 #define UINT64_FORMAT            "%"          PRIu64
 131 #define UINT64_FORMAT_X          "0x%"        PRIx64
 132 #define UINT64_FORMAT_X_0        "0x%016"     PRIx64
 133 #define UINT64_FORMAT_W(width)   "%"   #width PRIu64
 134 
 135 // Format integers which change size between 32- and 64-bit.
 136 #define SSIZE_FORMAT             "%"          PRIdPTR
 137 #define SSIZE_PLUS_FORMAT        "%+"         PRIdPTR
 138 #define SSIZE_FORMAT_W(width)    "%"   #width PRIdPTR
 139 #define SIZE_FORMAT              "%"          PRIuPTR
 140 #define SIZE_FORMAT_X            "0x%"        PRIxPTR
 141 #ifdef _LP64
 142 #define SIZE_FORMAT_X_0          "0x%016"     PRIxPTR
 143 #else
 144 #define SIZE_FORMAT_X_0          "0x%08"      PRIxPTR
 145 #endif
 146 #define SIZE_FORMAT_W(width)     "%"   #width PRIuPTR
 147 
 148 #define INTX_FORMAT              "%"          PRIdPTR
 149 #define INTX_FORMAT_X            "0x%"        PRIxPTR
 150 #define INTX_FORMAT_W(width)     "%"   #width PRIdPTR
 151 #define UINTX_FORMAT             "%"          PRIuPTR
 152 #define UINTX_FORMAT_X           "0x%"        PRIxPTR
 153 #define UINTX_FORMAT_W(width)    "%"   #width PRIuPTR
 154 
 155 // Format jlong, if necessary
 156 #ifndef JLONG_FORMAT
 157 #define JLONG_FORMAT             INT64_FORMAT
 158 #endif
 159 #ifndef JLONG_FORMAT_W
 160 #define JLONG_FORMAT_W(width)    INT64_FORMAT_W(width)
 161 #endif
 162 #ifndef JULONG_FORMAT
 163 #define JULONG_FORMAT            UINT64_FORMAT
 164 #endif
 165 #ifndef JULONG_FORMAT_X
 166 #define JULONG_FORMAT_X          UINT64_FORMAT_X
 167 #endif
 168 
 169 // Format pointers which change size between 32- and 64-bit.
 170 #ifdef  _LP64
 171 #define INTPTR_FORMAT            "0x%016"     PRIxPTR
 172 #define PTR_FORMAT               "0x%016"     PRIxPTR
 173 #else   // !_LP64
 174 #define INTPTR_FORMAT            "0x%08"      PRIxPTR
 175 #define PTR_FORMAT               "0x%08"      PRIxPTR
 176 #endif  // _LP64
 177 
 178 // Convert pointer to intptr_t, for use in printing pointers.
 179 inline intptr_t p2i(const volatile void* p) {
 180   return (intptr_t) p;
 181 }
 182 
 183 #define BOOL_TO_STR(_b_) ((_b_) ? "true" : "false")
 184 
 185 //----------------------------------------------------------------------------------------------------
 186 // Forbid the use of various C library functions.
 187 // Some of these have os:: replacements that should normally be used instead.
 188 // Others are considered security concerns, with preferred alternatives.
 189 
 190 FORBID_C_FUNCTION(void exit(int), "use os::exit");
 191 FORBID_C_FUNCTION(void _exit(int), "use os::exit");
 192 FORBID_C_FUNCTION(char* strerror(int), "use os::strerror");
 193 FORBID_C_FUNCTION(char* strtok(char*, const char*), "use strtok_r");
 194 FORBID_C_FUNCTION(int sprintf(char*, const char*, ...), "use os::snprintf");
 195 FORBID_C_FUNCTION(int vsprintf(char*, const char*, va_list), "use os::vsnprintf");
 196 FORBID_C_FUNCTION(int vsnprintf(char*, size_t, const char*, va_list), "use os::vsnprintf");
 197 
 198 // All of the following functions return raw C-heap pointers (sometimes as an option, e.g. realpath or getwd)
 199 // or, in case of free(), take raw C-heap pointers. Don't use them unless you are really sure you must.
 200 FORBID_C_FUNCTION(void* malloc(size_t size), "use os::malloc");
 201 FORBID_C_FUNCTION(void* calloc(size_t nmemb, size_t size), "use os::malloc and zero out manually");
 202 FORBID_C_FUNCTION(void free(void *ptr), "use os::free");
 203 FORBID_C_FUNCTION(void* realloc(void *ptr, size_t size), "use os::realloc");
 204 FORBID_C_FUNCTION(char* strdup(const char *s), "use os::strdup");
 205 FORBID_C_FUNCTION(char* strndup(const char *s, size_t n), "don't use");
 206 FORBID_C_FUNCTION(int posix_memalign(void **memptr, size_t alignment, size_t size), "don't use");
 207 FORBID_C_FUNCTION(void* aligned_alloc(size_t alignment, size_t size), "don't use");
 208 FORBID_C_FUNCTION(char* realpath(const char* path, char* resolved_path), "use os::Posix::realpath");
 209 FORBID_C_FUNCTION(char* get_current_dir_name(void), "use os::get_current_directory()");
 210 FORBID_C_FUNCTION(char* getwd(char *buf), "use os::get_current_directory()");
 211 FORBID_C_FUNCTION(wchar_t* wcsdup(const wchar_t *s), "don't use");
 212 FORBID_C_FUNCTION(void* reallocf(void *ptr, size_t size), "don't use");
 213 
 214 //----------------------------------------------------------------------------------------------------
 215 // Constants
 216 
 217 const int LogBytesPerShort   = 1;
 218 const int LogBytesPerInt     = 2;
 219 #ifdef _LP64
 220 const int LogBytesPerWord    = 3;
 221 #else
 222 const int LogBytesPerWord    = 2;
 223 #endif
 224 const int LogBytesPerLong    = 3;
 225 
 226 const int BytesPerShort      = 1 << LogBytesPerShort;
 227 const int BytesPerInt        = 1 << LogBytesPerInt;
 228 const int BytesPerWord       = 1 << LogBytesPerWord;
 229 const int BytesPerLong       = 1 << LogBytesPerLong;
 230 
 231 const int LogBitsPerByte     = 3;
 232 const int LogBitsPerShort    = LogBitsPerByte + LogBytesPerShort;
 233 const int LogBitsPerInt      = LogBitsPerByte + LogBytesPerInt;
 234 const int LogBitsPerWord     = LogBitsPerByte + LogBytesPerWord;
 235 const int LogBitsPerLong     = LogBitsPerByte + LogBytesPerLong;
 236 
 237 const int BitsPerByte        = 1 << LogBitsPerByte;
 238 const int BitsPerShort       = 1 << LogBitsPerShort;
 239 const int BitsPerInt         = 1 << LogBitsPerInt;
 240 const int BitsPerWord        = 1 << LogBitsPerWord;
 241 const int BitsPerLong        = 1 << LogBitsPerLong;
 242 
 243 const int WordAlignmentMask  = (1 << LogBytesPerWord) - 1;
 244 const int LongAlignmentMask  = (1 << LogBytesPerLong) - 1;
 245 
 246 const int WordsPerLong       = 2;       // Number of stack entries for longs
 247 
 248 const int oopSize            = sizeof(char*); // Full-width oop
 249 extern int heapOopSize;                       // Oop within a java object
 250 const int wordSize           = sizeof(char*);
 251 const int longSize           = sizeof(jlong);
 252 const int jintSize           = sizeof(jint);
 253 const int size_tSize         = sizeof(size_t);
 254 
 255 const int BytesPerOop        = BytesPerWord;  // Full-width oop
 256 
 257 extern int LogBytesPerHeapOop;                // Oop within a java object
 258 extern int LogBitsPerHeapOop;
 259 extern int BytesPerHeapOop;
 260 extern int BitsPerHeapOop;
 261 
 262 const int BitsPerJavaInteger = 32;
 263 const int BitsPerJavaLong    = 64;
 264 const int BitsPerSize_t      = size_tSize * BitsPerByte;
 265 
 266 // Size of a char[] needed to represent a jint as a string in decimal.
 267 const int jintAsStringSize = 12;
 268 
 269 // An opaque type, so that HeapWord* can be a generic pointer into the heap.
 270 // We require that object sizes be measured in units of heap words (e.g.
 271 // pointer-sized values), so that given HeapWord* hw,
 272 //   hw += oop(hw)->foo();
 273 // works, where foo is a method (like size or scavenge) that returns the
 274 // object size.
 275 class HeapWordImpl;             // Opaque, never defined.
 276 typedef HeapWordImpl* HeapWord;
 277 
 278 // Analogous opaque struct for metadata allocated from metaspaces.
 279 class MetaWordImpl;             // Opaque, never defined.
 280 typedef MetaWordImpl* MetaWord;
 281 
 282 // HeapWordSize must be 2^LogHeapWordSize.
 283 const int HeapWordSize        = sizeof(HeapWord);
 284 #ifdef _LP64
 285 const int LogHeapWordSize     = 3;
 286 #else
 287 const int LogHeapWordSize     = 2;
 288 #endif
 289 const int HeapWordsPerLong    = BytesPerLong / HeapWordSize;
 290 const int LogHeapWordsPerLong = LogBytesPerLong - LogHeapWordSize;
 291 
 292 // The minimum number of native machine words necessary to contain "byte_size"
 293 // bytes.
 294 inline size_t heap_word_size(size_t byte_size) {
 295   return (byte_size + (HeapWordSize-1)) >> LogHeapWordSize;
 296 }
 297 
 298 inline jfloat jfloat_cast(jint x);
 299 inline jdouble jdouble_cast(jlong x);
 300 
 301 //-------------------------------------------
 302 // Constant for jlong (standardized by C++11)
 303 
 304 // Build a 64bit integer constant
 305 #define CONST64(x)  (x ## LL)
 306 #define UCONST64(x) (x ## ULL)
 307 
 308 const jlong min_jlong = CONST64(0x8000000000000000);
 309 const jlong max_jlong = CONST64(0x7fffffffffffffff);
 310 
 311 //-------------------------------------------
 312 // Constant for jdouble
 313 const jlong min_jlongDouble = CONST64(0x0000000000000001);
 314 const jdouble min_jdouble = jdouble_cast(min_jlongDouble);
 315 const jlong max_jlongDouble = CONST64(0x7fefffffffffffff);
 316 const jdouble max_jdouble = jdouble_cast(max_jlongDouble);
 317 
 318 const size_t K                  = 1024;
 319 const size_t M                  = K*K;
 320 const size_t G                  = M*K;
 321 const size_t HWperKB            = K / sizeof(HeapWord);
 322 
 323 // Constants for converting from a base unit to milli-base units.  For
 324 // example from seconds to milliseconds and microseconds
 325 
 326 const int MILLIUNITS    = 1000;         // milli units per base unit
 327 const int MICROUNITS    = 1000000;      // micro units per base unit
 328 const int NANOUNITS     = 1000000000;   // nano units per base unit
 329 const int NANOUNITS_PER_MILLIUNIT = NANOUNITS / MILLIUNITS;
 330 
 331 const jlong NANOSECS_PER_SEC      = CONST64(1000000000);
 332 const jint  NANOSECS_PER_MILLISEC = 1000000;
 333 
 334 
 335 // Unit conversion functions
 336 // The caller is responsible for considering overflow.
 337 
 338 inline int64_t nanos_to_millis(int64_t nanos) {
 339   return nanos / NANOUNITS_PER_MILLIUNIT;
 340 }
 341 inline int64_t millis_to_nanos(int64_t millis) {
 342   return millis * NANOUNITS_PER_MILLIUNIT;
 343 }
 344 
 345 // Proper units routines try to maintain at least three significant digits.
 346 // In worst case, it would print five significant digits with lower prefix.
 347 // G is close to MAX_SIZE on 32-bit platforms, so its product can easily overflow,
 348 // and therefore we need to be careful.
 349 
 350 inline const char* proper_unit_for_byte_size(size_t s) {
 351 #ifdef _LP64
 352   if (s >= 100*G) {
 353     return "G";
 354   }
 355 #endif
 356   if (s >= 100*M) {
 357     return "M";
 358   } else if (s >= 100*K) {
 359     return "K";
 360   } else {
 361     return "B";
 362   }
 363 }
 364 
 365 template <class T>
 366 inline T byte_size_in_proper_unit(T s) {
 367 #ifdef _LP64
 368   if (s >= 100*G) {
 369     return (T)(s/G);
 370   }
 371 #endif
 372   if (s >= 100*M) {
 373     return (T)(s/M);
 374   } else if (s >= 100*K) {
 375     return (T)(s/K);
 376   } else {
 377     return s;
 378   }
 379 }
 380 
 381 #define PROPERFMT             SIZE_FORMAT "%s"
 382 #define PROPERFMTARGS(s)      byte_size_in_proper_unit(s), proper_unit_for_byte_size(s)
 383 
 384 inline const char* exact_unit_for_byte_size(size_t s) {
 385 #ifdef _LP64
 386   if (s >= G && (s % G) == 0) {
 387     return "G";
 388   }
 389 #endif
 390   if (s >= M && (s % M) == 0) {
 391     return "M";
 392   }
 393   if (s >= K && (s % K) == 0) {
 394     return "K";
 395   }
 396   return "B";
 397 }
 398 
 399 inline size_t byte_size_in_exact_unit(size_t s) {
 400 #ifdef _LP64
 401   if (s >= G && (s % G) == 0) {
 402     return s / G;
 403   }
 404 #endif
 405   if (s >= M && (s % M) == 0) {
 406     return s / M;
 407   }
 408   if (s >= K && (s % K) == 0) {
 409     return s / K;
 410   }
 411   return s;
 412 }
 413 
 414 #define EXACTFMT            SIZE_FORMAT "%s"
 415 #define EXACTFMTARGS(s)     byte_size_in_exact_unit(s), exact_unit_for_byte_size(s)
 416 
 417 // Memory size transition formatting.
 418 
 419 #define HEAP_CHANGE_FORMAT "%s: " SIZE_FORMAT "K(" SIZE_FORMAT "K)->" SIZE_FORMAT "K(" SIZE_FORMAT "K)"
 420 
 421 #define HEAP_CHANGE_FORMAT_ARGS(_name_, _prev_used_, _prev_capacity_, _used_, _capacity_) \
 422   (_name_), (_prev_used_) / K, (_prev_capacity_) / K, (_used_) / K, (_capacity_) / K
 423 
 424 //----------------------------------------------------------------------------------------------------
 425 // VM type definitions
 426 
 427 // intx and uintx are the 'extended' int and 'extended' unsigned int types;
 428 // they are 32bit wide on a 32-bit platform, and 64bit wide on a 64bit platform.
 429 
 430 typedef intptr_t  intx;
 431 typedef uintptr_t uintx;
 432 
 433 const intx  min_intx  = (intx)1 << (sizeof(intx)*BitsPerByte-1);
 434 const intx  max_intx  = (uintx)min_intx - 1;
 435 const uintx max_uintx = (uintx)-1;
 436 
 437 // Table of values:
 438 //      sizeof intx         4               8
 439 // min_intx             0x80000000      0x8000000000000000
 440 // max_intx             0x7FFFFFFF      0x7FFFFFFFFFFFFFFF
 441 // max_uintx            0xFFFFFFFF      0xFFFFFFFFFFFFFFFF
 442 
 443 typedef unsigned int uint;   NEEDS_CLEANUP
 444 
 445 
 446 //----------------------------------------------------------------------------------------------------
 447 // Java type definitions
 448 
 449 // All kinds of 'plain' byte addresses
 450 typedef   signed char s_char;
 451 typedef unsigned char u_char;
 452 typedef u_char*       address;
 453 typedef uintptr_t     address_word; // unsigned integer which will hold a pointer
 454                                     // except for some implementations of a C++
 455                                     // linkage pointer to function. Should never
 456                                     // need one of those to be placed in this
 457                                     // type anyway.
 458 
 459 //  Utility functions to "portably" (?) bit twiddle pointers
 460 //  Where portable means keep ANSI C++ compilers quiet
 461 
 462 inline address       set_address_bits(address x, int m)       { return address(intptr_t(x) | m); }
 463 inline address       clear_address_bits(address x, int m)     { return address(intptr_t(x) & ~m); }
 464 
 465 //  Utility functions to "portably" make cast to/from function pointers.
 466 
 467 inline address_word  mask_address_bits(address x, int m)      { return address_word(x) & m; }
 468 inline address_word  castable_address(address x)              { return address_word(x) ; }
 469 inline address_word  castable_address(void* x)                { return address_word(x) ; }
 470 
 471 // Pointer subtraction.
 472 // The idea here is to avoid ptrdiff_t, which is signed and so doesn't have
 473 // the range we might need to find differences from one end of the heap
 474 // to the other.
 475 // A typical use might be:
 476 //     if (pointer_delta(end(), top()) >= size) {
 477 //       // enough room for an object of size
 478 //       ...
 479 // and then additions like
 480 //       ... top() + size ...
 481 // are safe because we know that top() is at least size below end().
 482 inline size_t pointer_delta(const volatile void* left,
 483                             const volatile void* right,
 484                             size_t element_size) {
 485   assert(left >= right, "avoid underflow - left: " PTR_FORMAT " right: " PTR_FORMAT, p2i(left), p2i(right));
 486   return (((uintptr_t) left) - ((uintptr_t) right)) / element_size;
 487 }
 488 
 489 // A version specialized for HeapWord*'s.
 490 inline size_t pointer_delta(const HeapWord* left, const HeapWord* right) {
 491   return pointer_delta(left, right, sizeof(HeapWord));
 492 }
 493 // A version specialized for MetaWord*'s.
 494 inline size_t pointer_delta(const MetaWord* left, const MetaWord* right) {
 495   return pointer_delta(left, right, sizeof(MetaWord));
 496 }
 497 
 498 //
 499 // ANSI C++ does not allow casting from one pointer type to a function pointer
 500 // directly without at best a warning. This macro accomplishes it silently
 501 // In every case that is present at this point the value be cast is a pointer
 502 // to a C linkage function. In some case the type used for the cast reflects
 503 // that linkage and a picky compiler would not complain. In other cases because
 504 // there is no convenient place to place a typedef with extern C linkage (i.e
 505 // a platform dependent header file) it doesn't. At this point no compiler seems
 506 // picky enough to catch these instances (which are few). It is possible that
 507 // using templates could fix these for all cases. This use of templates is likely
 508 // so far from the middle of the road that it is likely to be problematic in
 509 // many C++ compilers.
 510 //
 511 #define CAST_TO_FN_PTR(func_type, value) (reinterpret_cast<func_type>(value))
 512 #define CAST_FROM_FN_PTR(new_type, func_ptr) ((new_type)((address_word)(func_ptr)))
 513 
 514 // In many places we've added C-style casts to silence compiler
 515 // warnings, for example when truncating a size_t to an int when we
 516 // know the size_t is a small struct. Such casts are risky because
 517 // they effectively disable useful compiler warnings. We can make our
 518 // lives safer with this function, which ensures that any cast is
 519 // reversible without loss of information. It doesn't check
 520 // everything: it isn't intended to make sure that pointer types are
 521 // compatible, for example.
 522 template <typename T2, typename T1>
 523 T2 checked_cast(T1 thing) {
 524   T2 result = static_cast<T2>(thing);
 525   assert(static_cast<T1>(result) == thing, "must be");
 526   return result;
 527 }
 528 
 529 // Need the correct linkage to call qsort without warnings
 530 extern "C" {
 531   typedef int (*_sort_Fn)(const void *, const void *);
 532 }
 533 
 534 // Additional Java basic types
 535 
 536 typedef uint8_t  jubyte;
 537 typedef uint16_t jushort;
 538 typedef uint32_t juint;
 539 typedef uint64_t julong;
 540 
 541 // Unsigned byte types for os and stream.hpp
 542 
 543 // Unsigned one, two, four and eight byte quantities used for describing
 544 // the .class file format. See JVM book chapter 4.
 545 
 546 typedef jubyte  u1;
 547 typedef jushort u2;
 548 typedef juint   u4;
 549 typedef julong  u8;
 550 
 551 const jubyte  max_jubyte  = (jubyte)-1;  // 0xFF       largest jubyte
 552 const jushort max_jushort = (jushort)-1; // 0xFFFF     largest jushort
 553 const juint   max_juint   = (juint)-1;   // 0xFFFFFFFF largest juint
 554 const julong  max_julong  = (julong)-1;  // 0xFF....FF largest julong
 555 
 556 typedef jbyte  s1;
 557 typedef jshort s2;
 558 typedef jint   s4;
 559 typedef jlong  s8;
 560 
 561 const jbyte min_jbyte = -(1 << 7);       // smallest jbyte
 562 const jbyte max_jbyte = (1 << 7) - 1;    // largest jbyte
 563 const jshort min_jshort = -(1 << 15);    // smallest jshort
 564 const jshort max_jshort = (1 << 15) - 1; // largest jshort
 565 
 566 const jint min_jint = (jint)1 << (sizeof(jint)*BitsPerByte-1); // 0x80000000 == smallest jint
 567 const jint max_jint = (juint)min_jint - 1;                     // 0x7FFFFFFF == largest jint
 568 
 569 const jint min_jintFloat = (jint)(0x00000001);
 570 const jfloat min_jfloat = jfloat_cast(min_jintFloat);
 571 const jint max_jintFloat = (jint)(0x7f7fffff);
 572 const jfloat max_jfloat = jfloat_cast(max_jintFloat);
 573 
 574 //----------------------------------------------------------------------------------------------------
 575 // JVM spec restrictions
 576 
 577 const int max_method_code_size = 64*K - 1;  // JVM spec, 2nd ed. section 4.8.1 (p.134)
 578 
 579 //----------------------------------------------------------------------------------------------------
 580 // old CDS options
 581 extern bool DumpSharedSpaces;
 582 extern bool DynamicDumpSharedSpaces;
 583 extern bool RequireSharedSpaces;
 584 extern "C" {
 585 // Make sure UseSharedSpaces is accessible to the serviceability agent.
 586 extern JNIEXPORT jboolean UseSharedSpaces;
 587 }
 588 
 589 //----------------------------------------------------------------------------------------------------
 590 // Object alignment, in units of HeapWords.
 591 //
 592 // Minimum is max(BytesPerLong, BytesPerDouble, BytesPerOop) / HeapWordSize, so jlong, jdouble and
 593 // reference fields can be naturally aligned.
 594 
 595 extern int MinObjAlignment;
 596 extern int MinObjAlignmentInBytes;
 597 extern int MinObjAlignmentInBytesMask;
 598 
 599 extern int LogMinObjAlignment;
 600 extern int LogMinObjAlignmentInBytes;
 601 
 602 const int LogKlassAlignmentInBytes = 3;
 603 const int LogKlassAlignment        = LogKlassAlignmentInBytes - LogHeapWordSize;
 604 const int KlassAlignmentInBytes    = 1 << LogKlassAlignmentInBytes;
 605 const int KlassAlignment           = KlassAlignmentInBytes / HeapWordSize;
 606 
 607 // Maximal size of heap where unscaled compression can be used. Also upper bound
 608 // for heap placement: 4GB.
 609 const  uint64_t UnscaledOopHeapMax = (uint64_t(max_juint) + 1);
 610 // Maximal size of heap where compressed oops can be used. Also upper bound for heap
 611 // placement for zero based compression algorithm: UnscaledOopHeapMax << LogMinObjAlignmentInBytes.
 612 extern uint64_t OopEncodingHeapMax;
 613 
 614 // Maximal size of compressed class space. Above this limit compression is not possible.
 615 // Also upper bound for placement of zero based class space. (Class space is further limited
 616 // to be < 3G, see arguments.cpp.)
 617 const  uint64_t KlassEncodingMetaspaceMax = (uint64_t(max_juint) + 1) << LogKlassAlignmentInBytes;
 618 
 619 // Machine dependent stuff
 620 
 621 // The maximum size of the code cache.  Can be overridden by targets.
 622 #define CODE_CACHE_SIZE_LIMIT (2*G)
 623 // Allow targets to reduce the default size of the code cache.
 624 #define CODE_CACHE_DEFAULT_LIMIT CODE_CACHE_SIZE_LIMIT
 625 
 626 #include CPU_HEADER(globalDefinitions)
 627 
 628 // To assure the IRIW property on processors that are not multiple copy
 629 // atomic, sync instructions must be issued between volatile reads to
 630 // assure their ordering, instead of after volatile stores.
 631 // (See "A Tutorial Introduction to the ARM and POWER Relaxed Memory Models"
 632 // by Luc Maranget, Susmit Sarkar and Peter Sewell, INRIA/Cambridge)
 633 #ifdef CPU_MULTI_COPY_ATOMIC
 634 // Not needed.
 635 const bool support_IRIW_for_not_multiple_copy_atomic_cpu = false;
 636 #else
 637 // From all non-multi-copy-atomic architectures, only PPC64 supports IRIW at the moment.
 638 // Final decision is subject to JEP 188: Java Memory Model Update.
 639 const bool support_IRIW_for_not_multiple_copy_atomic_cpu = PPC64_ONLY(true) NOT_PPC64(false);
 640 #endif
 641 
 642 // The expected size in bytes of a cache line, used to pad data structures.
 643 #ifndef DEFAULT_CACHE_LINE_SIZE
 644 #error "Platform should define DEFAULT_CACHE_LINE_SIZE"
 645 #endif
 646 
 647 
 648 //----------------------------------------------------------------------------------------------------
 649 // Utility macros for compilers
 650 // used to silence compiler warnings
 651 
 652 #define Unused_Variable(var) var
 653 
 654 
 655 //----------------------------------------------------------------------------------------------------
 656 // Miscellaneous
 657 
 658 // 6302670 Eliminate Hotspot __fabsf dependency
 659 // All fabs() callers should call this function instead, which will implicitly
 660 // convert the operand to double, avoiding a dependency on __fabsf which
 661 // doesn't exist in early versions of Solaris 8.
 662 inline double fabsd(double value) {
 663   return fabs(value);
 664 }
 665 
 666 // Returns numerator/denominator as percentage value from 0 to 100. If denominator
 667 // is zero, return 0.0.
 668 template<typename T>
 669 inline double percent_of(T numerator, T denominator) {
 670   return denominator != 0 ? (double)numerator / denominator * 100.0 : 0.0;
 671 }
 672 
 673 //----------------------------------------------------------------------------------------------------
 674 // Special casts
 675 // Cast floats into same-size integers and vice-versa w/o changing bit-pattern
 676 typedef union {
 677   jfloat f;
 678   jint i;
 679 } FloatIntConv;
 680 
 681 typedef union {
 682   jdouble d;
 683   jlong l;
 684   julong ul;
 685 } DoubleLongConv;
 686 
 687 inline jint    jint_cast    (jfloat  x)  { return ((FloatIntConv*)&x)->i; }
 688 inline jfloat  jfloat_cast  (jint    x)  { return ((FloatIntConv*)&x)->f; }
 689 
 690 inline jlong   jlong_cast   (jdouble x)  { return ((DoubleLongConv*)&x)->l;  }
 691 inline julong  julong_cast  (jdouble x)  { return ((DoubleLongConv*)&x)->ul; }
 692 inline jdouble jdouble_cast (jlong   x)  { return ((DoubleLongConv*)&x)->d;  }
 693 
 694 inline jint low (jlong value)                    { return jint(value); }
 695 inline jint high(jlong value)                    { return jint(value >> 32); }
 696 
 697 // the fancy casts are a hopefully portable way
 698 // to do unsigned 32 to 64 bit type conversion
 699 inline void set_low (jlong* value, jint low )    { *value &= (jlong)0xffffffff << 32;
 700                                                    *value |= (jlong)(julong)(juint)low; }
 701 
 702 inline void set_high(jlong* value, jint high)    { *value &= (jlong)(julong)(juint)0xffffffff;
 703                                                    *value |= (jlong)high       << 32; }
 704 
 705 inline jlong jlong_from(jint h, jint l) {
 706   jlong result = 0; // initialization to avoid warning
 707   set_high(&result, h);
 708   set_low(&result,  l);
 709   return result;
 710 }
 711 
 712 union jlong_accessor {
 713   jint  words[2];
 714   jlong long_value;
 715 };
 716 
 717 void basic_types_init(); // cannot define here; uses assert
 718 
 719 
 720 // NOTE: replicated in SA in vm/agent/sun/jvm/hotspot/runtime/BasicType.java
 721 enum BasicType {
 722 // The values T_BOOLEAN..T_LONG (4..11) are derived from the JVMS.
 723   T_BOOLEAN     = JVM_T_BOOLEAN,
 724   T_CHAR        = JVM_T_CHAR,
 725   T_FLOAT       = JVM_T_FLOAT,
 726   T_DOUBLE      = JVM_T_DOUBLE,
 727   T_BYTE        = JVM_T_BYTE,
 728   T_SHORT       = JVM_T_SHORT,
 729   T_INT         = JVM_T_INT,
 730   T_LONG        = JVM_T_LONG,
 731   // The remaining values are not part of any standard.
 732   // T_OBJECT and T_VOID denote two more semantic choices
 733   // for method return values.
 734   // T_OBJECT and T_ARRAY describe signature syntax.
 735   // T_ADDRESS, T_METADATA, T_NARROWOOP, T_NARROWKLASS describe
 736   // internal references within the JVM as if they were Java
 737   // types in their own right.
 738   T_OBJECT      = 12,
 739   T_ARRAY       = 13,
 740   T_VOID        = 14,
 741   T_ADDRESS     = 15,
 742   T_NARROWOOP   = 16,
 743   T_METADATA    = 17,
 744   T_NARROWKLASS = 18,
 745   T_CONFLICT    = 19, // for stack value type with conflicting contents
 746   T_ILLEGAL     = 99
 747 };
 748 
 749 #define SIGNATURE_TYPES_DO(F, N)                \
 750     F(JVM_SIGNATURE_BOOLEAN, T_BOOLEAN, N)      \
 751     F(JVM_SIGNATURE_CHAR,    T_CHAR,    N)      \
 752     F(JVM_SIGNATURE_FLOAT,   T_FLOAT,   N)      \
 753     F(JVM_SIGNATURE_DOUBLE,  T_DOUBLE,  N)      \
 754     F(JVM_SIGNATURE_BYTE,    T_BYTE,    N)      \
 755     F(JVM_SIGNATURE_SHORT,   T_SHORT,   N)      \
 756     F(JVM_SIGNATURE_INT,     T_INT,     N)      \
 757     F(JVM_SIGNATURE_LONG,    T_LONG,    N)      \
 758     F(JVM_SIGNATURE_CLASS,   T_OBJECT,  N)      \
 759     F(JVM_SIGNATURE_ARRAY,   T_ARRAY,   N)      \
 760     F(JVM_SIGNATURE_VOID,    T_VOID,    N)      \
 761     /*end*/
 762 
 763 inline bool is_java_type(BasicType t) {
 764   return T_BOOLEAN <= t && t <= T_VOID;
 765 }
 766 
 767 inline bool is_java_primitive(BasicType t) {
 768   return T_BOOLEAN <= t && t <= T_LONG;
 769 }
 770 
 771 inline bool is_subword_type(BasicType t) {
 772   // these guys are processed exactly like T_INT in calling sequences:
 773   return (t == T_BOOLEAN || t == T_CHAR || t == T_BYTE || t == T_SHORT);
 774 }
 775 
 776 inline bool is_signed_subword_type(BasicType t) {
 777   return (t == T_BYTE || t == T_SHORT);
 778 }
 779 
 780 inline bool is_unsigned_subword_type(BasicType t) {
 781   return (t == T_BOOLEAN || t == T_CHAR);
 782 }
 783 
 784 inline bool is_double_word_type(BasicType t) {
 785   return (t == T_DOUBLE || t == T_LONG);
 786 }
 787 
 788 inline bool is_reference_type(BasicType t, bool include_narrow_oop = false) {
 789   return (t == T_OBJECT || t == T_ARRAY || (include_narrow_oop && t == T_NARROWOOP));
 790 }
 791 
 792 inline bool is_integral_type(BasicType t) {
 793   return is_subword_type(t) || t == T_INT || t == T_LONG;
 794 }
 795 
 796 inline bool is_non_subword_integral_type(BasicType t) {
 797   return t == T_INT || t == T_LONG;
 798 }
 799 
 800 inline bool is_floating_point_type(BasicType t) {
 801   return (t == T_FLOAT || t == T_DOUBLE);
 802 }
 803 
 804 extern char type2char_tab[T_CONFLICT+1];     // Map a BasicType to a jchar
 805 inline char type2char(BasicType t) { return (uint)t < T_CONFLICT+1 ? type2char_tab[t] : 0; }
 806 extern int type2size[T_CONFLICT+1];         // Map BasicType to result stack elements
 807 extern const char* type2name_tab[T_CONFLICT+1];     // Map a BasicType to a char*
 808 extern BasicType name2type(const char* name);
 809 
 810 const char* type2name(BasicType t);
 811 
 812 inline jlong max_signed_integer(BasicType bt) {
 813   if (bt == T_INT) {
 814     return max_jint;
 815   }
 816   assert(bt == T_LONG, "unsupported");
 817   return max_jlong;
 818 }
 819 
 820 inline jlong min_signed_integer(BasicType bt) {
 821   if (bt == T_INT) {
 822     return min_jint;
 823   }
 824   assert(bt == T_LONG, "unsupported");
 825   return min_jlong;
 826 }
 827 
 828 // Auxiliary math routines
 829 // least common multiple
 830 extern size_t lcm(size_t a, size_t b);
 831 
 832 
 833 // NOTE: replicated in SA in vm/agent/sun/jvm/hotspot/runtime/BasicType.java
 834 enum BasicTypeSize {
 835   T_BOOLEAN_size     = 1,
 836   T_CHAR_size        = 1,
 837   T_FLOAT_size       = 1,
 838   T_DOUBLE_size      = 2,
 839   T_BYTE_size        = 1,
 840   T_SHORT_size       = 1,
 841   T_INT_size         = 1,
 842   T_LONG_size        = 2,
 843   T_OBJECT_size      = 1,
 844   T_ARRAY_size       = 1,
 845   T_NARROWOOP_size   = 1,
 846   T_NARROWKLASS_size = 1,
 847   T_VOID_size        = 0
 848 };
 849 
 850 // this works on valid parameter types but not T_VOID, T_CONFLICT, etc.
 851 inline int parameter_type_word_count(BasicType t) {
 852   if (is_double_word_type(t))  return 2;
 853   assert(is_java_primitive(t) || is_reference_type(t), "no goofy types here please");
 854   assert(type2size[t] == 1, "must be");
 855   return 1;
 856 }
 857 
 858 // maps a BasicType to its instance field storage type:
 859 // all sub-word integral types are widened to T_INT
 860 extern BasicType type2field[T_CONFLICT+1];
 861 extern BasicType type2wfield[T_CONFLICT+1];
 862 
 863 
 864 // size in bytes
 865 enum ArrayElementSize {
 866   T_BOOLEAN_aelem_bytes     = 1,
 867   T_CHAR_aelem_bytes        = 2,
 868   T_FLOAT_aelem_bytes       = 4,
 869   T_DOUBLE_aelem_bytes      = 8,
 870   T_BYTE_aelem_bytes        = 1,
 871   T_SHORT_aelem_bytes       = 2,
 872   T_INT_aelem_bytes         = 4,
 873   T_LONG_aelem_bytes        = 8,
 874 #ifdef _LP64
 875   T_OBJECT_aelem_bytes      = 8,
 876   T_ARRAY_aelem_bytes       = 8,
 877 #else
 878   T_OBJECT_aelem_bytes      = 4,
 879   T_ARRAY_aelem_bytes       = 4,
 880 #endif
 881   T_NARROWOOP_aelem_bytes   = 4,
 882   T_NARROWKLASS_aelem_bytes = 4,
 883   T_VOID_aelem_bytes        = 0
 884 };
 885 
 886 extern int _type2aelembytes[T_CONFLICT+1]; // maps a BasicType to nof bytes used by its array element
 887 #ifdef ASSERT
 888 extern int type2aelembytes(BasicType t, bool allow_address = false); // asserts
 889 #else
 890 inline int type2aelembytes(BasicType t, bool allow_address = false) { return _type2aelembytes[t]; }
 891 #endif
 892 
 893 inline bool same_type_or_subword_size(BasicType t1, BasicType t2) {
 894   return (t1 == t2) || (is_subword_type(t1) && type2aelembytes(t1) == type2aelembytes(t2));
 895 }
 896 
 897 // JavaValue serves as a container for arbitrary Java values.
 898 
 899 class JavaValue {
 900 
 901  public:
 902   typedef union JavaCallValue {
 903     jfloat   f;
 904     jdouble  d;
 905     jint     i;
 906     jlong    l;
 907     jobject  h;
 908     oopDesc* o;
 909   } JavaCallValue;
 910 
 911  private:
 912   BasicType _type;
 913   JavaCallValue _value;
 914 
 915  public:
 916   JavaValue(BasicType t = T_ILLEGAL) { _type = t; }
 917 
 918   JavaValue(jfloat value) {
 919     _type    = T_FLOAT;
 920     _value.f = value;
 921   }
 922 
 923   JavaValue(jdouble value) {
 924     _type    = T_DOUBLE;
 925     _value.d = value;
 926   }
 927 
 928  jfloat get_jfloat() const { return _value.f; }
 929  jdouble get_jdouble() const { return _value.d; }
 930  jint get_jint() const { return _value.i; }
 931  jlong get_jlong() const { return _value.l; }
 932  jobject get_jobject() const { return _value.h; }
 933  oopDesc* get_oop() const { return _value.o; }
 934  JavaCallValue* get_value_addr() { return &_value; }
 935  BasicType get_type() const { return _type; }
 936 
 937  void set_jfloat(jfloat f) { _value.f = f;}
 938  void set_jdouble(jdouble d) { _value.d = d;}
 939  void set_jint(jint i) { _value.i = i;}
 940  void set_jlong(jlong l) { _value.l = l;}
 941  void set_jobject(jobject h) { _value.h = h;}
 942  void set_oop(oopDesc* o) { _value.o = o;}
 943  void set_type(BasicType t) { _type = t; }
 944 
 945  jboolean get_jboolean() const { return (jboolean) (_value.i);}
 946  jbyte get_jbyte() const { return (jbyte) (_value.i);}
 947  jchar get_jchar() const { return (jchar) (_value.i);}
 948  jshort get_jshort() const { return (jshort) (_value.i);}
 949 
 950 };
 951 
 952 
 953 // TosState describes the top-of-stack state before and after the execution of
 954 // a bytecode or method. The top-of-stack value may be cached in one or more CPU
 955 // registers. The TosState corresponds to the 'machine representation' of this cached
 956 // value. There's 4 states corresponding to the JAVA types int, long, float & double
 957 // as well as a 5th state in case the top-of-stack value is actually on the top
 958 // of stack (in memory) and thus not cached. The atos state corresponds to the itos
 959 // state when it comes to machine representation but is used separately for (oop)
 960 // type specific operations (e.g. verification code).
 961 
 962 enum TosState {         // describes the tos cache contents
 963   btos = 0,             // byte, bool tos cached
 964   ztos = 1,             // byte, bool tos cached
 965   ctos = 2,             // char tos cached
 966   stos = 3,             // short tos cached
 967   itos = 4,             // int tos cached
 968   ltos = 5,             // long tos cached
 969   ftos = 6,             // float tos cached
 970   dtos = 7,             // double tos cached
 971   atos = 8,             // object cached
 972   vtos = 9,             // tos not cached
 973   number_of_states,
 974   ilgl                  // illegal state: should not occur
 975 };
 976 
 977 
 978 inline TosState as_TosState(BasicType type) {
 979   switch (type) {
 980     case T_BYTE   : return btos;
 981     case T_BOOLEAN: return ztos;
 982     case T_CHAR   : return ctos;
 983     case T_SHORT  : return stos;
 984     case T_INT    : return itos;
 985     case T_LONG   : return ltos;
 986     case T_FLOAT  : return ftos;
 987     case T_DOUBLE : return dtos;
 988     case T_VOID   : return vtos;
 989     case T_ARRAY  : // fall through
 990     case T_OBJECT : return atos;
 991     default       : return ilgl;
 992   }
 993 }
 994 
 995 inline BasicType as_BasicType(TosState state) {
 996   switch (state) {
 997     case btos : return T_BYTE;
 998     case ztos : return T_BOOLEAN;
 999     case ctos : return T_CHAR;
1000     case stos : return T_SHORT;
1001     case itos : return T_INT;
1002     case ltos : return T_LONG;
1003     case ftos : return T_FLOAT;
1004     case dtos : return T_DOUBLE;
1005     case atos : return T_OBJECT;
1006     case vtos : return T_VOID;
1007     default   : return T_ILLEGAL;
1008   }
1009 }
1010 
1011 
1012 // Helper function to convert BasicType info into TosState
1013 // Note: Cannot define here as it uses global constant at the time being.
1014 TosState as_TosState(BasicType type);
1015 
1016 
1017 // JavaThreadState keeps track of which part of the code a thread is executing in. This
1018 // information is needed by the safepoint code.
1019 //
1020 // There are 4 essential states:
1021 //
1022 //  _thread_new         : Just started, but not executed init. code yet (most likely still in OS init code)
1023 //  _thread_in_native   : In native code. This is a safepoint region, since all oops will be in jobject handles
1024 //  _thread_in_vm       : Executing in the vm
1025 //  _thread_in_Java     : Executing either interpreted or compiled Java code (or could be in a stub)
1026 //
1027 // Each state has an associated xxxx_trans state, which is an intermediate state used when a thread is in
1028 // a transition from one state to another. These extra states makes it possible for the safepoint code to
1029 // handle certain thread_states without having to suspend the thread - making the safepoint code faster.
1030 //
1031 // Given a state, the xxxx_trans state can always be found by adding 1.
1032 //
1033 enum JavaThreadState {
1034   _thread_uninitialized     =  0, // should never happen (missing initialization)
1035   _thread_new               =  2, // just starting up, i.e., in process of being initialized
1036   _thread_new_trans         =  3, // corresponding transition state (not used, included for completeness)
1037   _thread_in_native         =  4, // running in native code
1038   _thread_in_native_trans   =  5, // corresponding transition state
1039   _thread_in_vm             =  6, // running in VM
1040   _thread_in_vm_trans       =  7, // corresponding transition state
1041   _thread_in_Java           =  8, // running in Java or in stub code
1042   _thread_in_Java_trans     =  9, // corresponding transition state (not used, included for completeness)
1043   _thread_blocked           = 10, // blocked in vm
1044   _thread_blocked_trans     = 11, // corresponding transition state
1045   _thread_max_state         = 12  // maximum thread state+1 - used for statistics allocation
1046 };
1047 
1048 enum LockingMode {
1049   // Use only heavy monitors for locking
1050   LM_MONITOR     = 0,
1051   // Legacy stack-locking, with monitors as 2nd tier
1052   LM_LEGACY      = 1,
1053   // New lightweight locking, with monitors as 2nd tier
1054   LM_LIGHTWEIGHT = 2
1055 };
1056 
1057 //----------------------------------------------------------------------------------------------------
1058 // Special constants for debugging
1059 
1060 const jint     badInt           = -3;                       // generic "bad int" value
1061 const intptr_t badAddressVal    = -2;                       // generic "bad address" value
1062 const intptr_t badOopVal        = -1;                       // generic "bad oop" value
1063 const intptr_t badHeapOopVal    = (intptr_t) CONST64(0x2BAD4B0BBAADBABE); // value used to zap heap after GC
1064 const int      badStackSegVal   = 0xCA;                     // value used to zap stack segments
1065 const int      badHandleValue   = 0xBC;                     // value used to zap vm handle area
1066 const int      badResourceValue = 0xAB;                     // value used to zap resource area
1067 const int      freeBlockPad     = 0xBA;                     // value used to pad freed blocks.
1068 const int      uninitBlockPad   = 0xF1;                     // value used to zap newly malloc'd blocks.
1069 const juint    uninitMetaWordVal= 0xf7f7f7f7;               // value used to zap newly allocated metachunk
1070 const juint    badHeapWordVal   = 0xBAADBABE;               // value used to zap heap after GC
1071 const juint    badMetaWordVal   = 0xBAADFADE;               // value used to zap metadata heap after GC
1072 const int      badCodeHeapNewVal= 0xCC;                     // value used to zap Code heap at allocation
1073 const int      badCodeHeapFreeVal = 0xDD;                   // value used to zap Code heap at deallocation
1074 
1075 
1076 // (These must be implemented as #defines because C++ compilers are
1077 // not obligated to inline non-integral constants!)
1078 #define       badAddress        ((address)::badAddressVal)
1079 #define       badHeapWord       (::badHeapWordVal)
1080 
1081 // Default TaskQueue size is 16K (32-bit) or 128K (64-bit)
1082 #define TASKQUEUE_SIZE (NOT_LP64(1<<14) LP64_ONLY(1<<17))
1083 
1084 //----------------------------------------------------------------------------------------------------
1085 // Utility functions for bitfield manipulations
1086 
1087 const intptr_t AllBits    = ~0; // all bits set in a word
1088 const intptr_t NoBits     =  0; // no bits set in a word
1089 const jlong    NoLongBits =  0; // no bits set in a long
1090 const intptr_t OneBit     =  1; // only right_most bit set in a word
1091 
1092 // get a word with the n.th or the right-most or left-most n bits set
1093 // (note: #define used only so that they can be used in enum constant definitions)
1094 #define nth_bit(n)        (((n) >= BitsPerWord) ? 0 : (OneBit << (n)))
1095 #define right_n_bits(n)   (nth_bit(n) - 1)
1096 
1097 // bit-operations using a mask m
1098 inline void   set_bits    (intptr_t& x, intptr_t m) { x |= m; }
1099 inline void clear_bits    (intptr_t& x, intptr_t m) { x &= ~m; }
1100 inline intptr_t mask_bits      (intptr_t  x, intptr_t m) { return x & m; }
1101 inline jlong    mask_long_bits (jlong     x, jlong    m) { return x & m; }
1102 inline bool mask_bits_are_true (intptr_t flags, intptr_t mask) { return (flags & mask) == mask; }
1103 
1104 // bit-operations using the n.th bit
1105 inline void    set_nth_bit(intptr_t& x, int n) { set_bits  (x, nth_bit(n)); }
1106 inline void  clear_nth_bit(intptr_t& x, int n) { clear_bits(x, nth_bit(n)); }
1107 inline bool is_set_nth_bit(intptr_t  x, int n) { return mask_bits (x, nth_bit(n)) != NoBits; }
1108 
1109 // returns the bitfield of x starting at start_bit_no with length field_length (no sign-extension!)
1110 inline intptr_t bitfield(intptr_t x, int start_bit_no, int field_length) {
1111   return mask_bits(x >> start_bit_no, right_n_bits(field_length));
1112 }
1113 
1114 
1115 //----------------------------------------------------------------------------------------------------
1116 // Utility functions for integers
1117 
1118 // Avoid use of global min/max macros which may cause unwanted double
1119 // evaluation of arguments.
1120 #ifdef max
1121 #undef max
1122 #endif
1123 
1124 #ifdef min
1125 #undef min
1126 #endif
1127 
1128 // It is necessary to use templates here. Having normal overloaded
1129 // functions does not work because it is necessary to provide both 32-
1130 // and 64-bit overloaded functions, which does not work, and having
1131 // explicitly-typed versions of these routines (i.e., MAX2I, MAX2L)
1132 // will be even more error-prone than macros.
1133 template<class T> constexpr T MAX2(T a, T b)           { return (a > b) ? a : b; }
1134 template<class T> constexpr T MIN2(T a, T b)           { return (a < b) ? a : b; }
1135 template<class T> constexpr T MAX3(T a, T b, T c)      { return MAX2(MAX2(a, b), c); }
1136 template<class T> constexpr T MIN3(T a, T b, T c)      { return MIN2(MIN2(a, b), c); }
1137 template<class T> constexpr T MAX4(T a, T b, T c, T d) { return MAX2(MAX3(a, b, c), d); }
1138 template<class T> constexpr T MIN4(T a, T b, T c, T d) { return MIN2(MIN3(a, b, c), d); }
1139 
1140 template<class T> inline T ABS(T x)                 { return (x > 0) ? x : -x; }
1141 
1142 // Return the given value clamped to the range [min ... max]
1143 template<typename T>
1144 inline T clamp(T value, T min, T max) {
1145   assert(min <= max, "must be");
1146   return MIN2(MAX2(value, min), max);
1147 }
1148 
1149 inline bool is_odd (intx x) { return x & 1;      }
1150 inline bool is_even(intx x) { return !is_odd(x); }
1151 
1152 // abs methods which cannot overflow and so are well-defined across
1153 // the entire domain of integer types.
1154 static inline unsigned int uabs(unsigned int n) {
1155   union {
1156     unsigned int result;
1157     int value;
1158   };
1159   result = n;
1160   if (value < 0) result = 0-result;
1161   return result;
1162 }
1163 static inline julong uabs(julong n) {
1164   union {
1165     julong result;
1166     jlong value;
1167   };
1168   result = n;
1169   if (value < 0) result = 0-result;
1170   return result;
1171 }
1172 static inline julong uabs(jlong n) { return uabs((julong)n); }
1173 static inline unsigned int uabs(int n) { return uabs((unsigned int)n); }
1174 
1175 // "to" should be greater than "from."
1176 inline intx byte_size(void* from, void* to) {
1177   return (address)to - (address)from;
1178 }
1179 
1180 // Pack and extract shorts to/from ints:
1181 
1182 inline u2 extract_low_short_from_int(u4 x) {
1183   return u2(x & 0xffff);
1184 }
1185 
1186 inline u2 extract_high_short_from_int(u4 x) {
1187   return u2((x >> 16) & 0xffff);
1188 }
1189 
1190 inline int build_int_from_shorts( u2 low, u2 high ) {
1191   return ((int)((unsigned int)high << 16) | (unsigned int)low);
1192 }
1193 
1194 // swap a & b
1195 template<class T> static void swap(T& a, T& b) {
1196   T tmp = a;
1197   a = b;
1198   b = tmp;
1199 }
1200 
1201 // array_size_impl is a function that takes a reference to T[N] and
1202 // returns a reference to char[N].  It is not ODR-used, so not defined.
1203 template<typename T, size_t N> char (&array_size_impl(T (&)[N]))[N];
1204 
1205 #define ARRAY_SIZE(array) sizeof(array_size_impl(array))
1206 
1207 //----------------------------------------------------------------------------------------------------
1208 // Sum and product which can never overflow: they wrap, just like the
1209 // Java operations.  Note that we don't intend these to be used for
1210 // general-purpose arithmetic: their purpose is to emulate Java
1211 // operations.
1212 
1213 // The goal of this code to avoid undefined or implementation-defined
1214 // behavior.  The use of an lvalue to reference cast is explicitly
1215 // permitted by Lvalues and rvalues [basic.lval].  [Section 3.10 Para
1216 // 15 in C++03]
1217 #define JAVA_INTEGER_OP(OP, NAME, TYPE, UNSIGNED_TYPE)  \
1218 inline TYPE NAME (TYPE in1, TYPE in2) {                 \
1219   UNSIGNED_TYPE ures = static_cast<UNSIGNED_TYPE>(in1); \
1220   ures OP ## = static_cast<UNSIGNED_TYPE>(in2);         \
1221   return reinterpret_cast<TYPE&>(ures);                 \
1222 }
1223 
1224 JAVA_INTEGER_OP(+, java_add, jint, juint)
1225 JAVA_INTEGER_OP(-, java_subtract, jint, juint)
1226 JAVA_INTEGER_OP(*, java_multiply, jint, juint)
1227 JAVA_INTEGER_OP(+, java_add, jlong, julong)
1228 JAVA_INTEGER_OP(-, java_subtract, jlong, julong)
1229 JAVA_INTEGER_OP(*, java_multiply, jlong, julong)
1230 
1231 inline jint  java_negate(jint  v) { return java_subtract((jint) 0, v); }
1232 inline jlong java_negate(jlong v) { return java_subtract((jlong)0, v); }
1233 
1234 #undef JAVA_INTEGER_OP
1235 
1236 // Provide integer shift operations with Java semantics.  No overflow
1237 // issues - left shifts simply discard shifted out bits.  No undefined
1238 // behavior for large or negative shift quantities; instead the actual
1239 // shift distance is the argument modulo the lhs value's size in bits.
1240 // No undefined or implementation defined behavior for shifting negative
1241 // values; left shift discards bits, right shift sign extends.  We use
1242 // the same safe conversion technique as above for java_add and friends.
1243 #define JAVA_INTEGER_SHIFT_OP(OP, NAME, TYPE, XTYPE)    \
1244 inline TYPE NAME (TYPE lhs, jint rhs) {                 \
1245   const uint rhs_mask = (sizeof(TYPE) * 8) - 1;         \
1246   STATIC_ASSERT(rhs_mask == 31 || rhs_mask == 63);      \
1247   XTYPE xres = static_cast<XTYPE>(lhs);                 \
1248   xres OP ## = (rhs & rhs_mask);                        \
1249   return reinterpret_cast<TYPE&>(xres);                 \
1250 }
1251 
1252 JAVA_INTEGER_SHIFT_OP(<<, java_shift_left, jint, juint)
1253 JAVA_INTEGER_SHIFT_OP(<<, java_shift_left, jlong, julong)
1254 
1255 // For signed shift right, assume C++ implementation >> sign extends.
1256 //
1257 // C++14 5.8/3: In the description of "E1 >> E2" it says "If E1 has a signed type
1258 // and a negative value, the resulting value is implementation-defined."
1259 //
1260 // However, C++20 7.6.7/3 further defines integral arithmetic, as part of
1261 // requiring two's-complement behavior.
1262 // https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2018/p0907r3.html
1263 // https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2018/p1236r1.html
1264 // The corresponding C++20 text is "Right-shift on signed integral types is an
1265 // arithmetic right shift, which performs sign-extension."
1266 //
1267 // As discussed in the two's complement proposal, all known modern C++ compilers
1268 // already behave that way. And it is unlikely any would go off and do something
1269 // different now, with C++20 tightening things up.
1270 JAVA_INTEGER_SHIFT_OP(>>, java_shift_right, jint, jint)
1271 JAVA_INTEGER_SHIFT_OP(>>, java_shift_right, jlong, jlong)
1272 // For >>> use C++ unsigned >>.
1273 JAVA_INTEGER_SHIFT_OP(>>, java_shift_right_unsigned, jint, juint)
1274 JAVA_INTEGER_SHIFT_OP(>>, java_shift_right_unsigned, jlong, julong)
1275 
1276 #undef JAVA_INTEGER_SHIFT_OP
1277 
1278 //----------------------------------------------------------------------------------------------------
1279 // The goal of this code is to provide saturating operations for int/uint.
1280 // Checks overflow conditions and saturates the result to min_jint/max_jint.
1281 #define SATURATED_INTEGER_OP(OP, NAME, TYPE1, TYPE2) \
1282 inline int NAME (TYPE1 in1, TYPE2 in2) {             \
1283   jlong res = static_cast<jlong>(in1);               \
1284   res OP ## = static_cast<jlong>(in2);               \
1285   if (res > max_jint) {                              \
1286     res = max_jint;                                  \
1287   } else if (res < min_jint) {                       \
1288     res = min_jint;                                  \
1289   }                                                  \
1290   return static_cast<int>(res);                      \
1291 }
1292 
1293 SATURATED_INTEGER_OP(+, saturated_add, int, int)
1294 SATURATED_INTEGER_OP(+, saturated_add, int, uint)
1295 SATURATED_INTEGER_OP(+, saturated_add, uint, int)
1296 SATURATED_INTEGER_OP(+, saturated_add, uint, uint)
1297 
1298 #undef SATURATED_INTEGER_OP
1299 
1300 // Taken from rom section 8-2 of Henry S. Warren, Jr., Hacker's Delight (2nd ed.) (Addison Wesley, 2013), 173-174.
1301 inline uint64_t multiply_high_unsigned(const uint64_t x, const uint64_t y) {
1302   const uint64_t x1 = x >> 32u;
1303   const uint64_t x2 = x & 0xFFFFFFFF;
1304   const uint64_t y1 = y >> 32u;
1305   const uint64_t y2 = y & 0xFFFFFFFF;
1306   const uint64_t z2 = x2 * y2;
1307   const uint64_t t = x1 * y2 + (z2 >> 32u);
1308   uint64_t z1 = t & 0xFFFFFFFF;
1309   const uint64_t z0 = t >> 32u;
1310   z1 += x2 * y1;
1311 
1312   return x1 * y1 + z0 + (z1 >> 32u);
1313 }
1314 
1315 // Taken from java.lang.Math::multiplyHigh which uses the technique from section 8-2 of Henry S. Warren, Jr.,
1316 // Hacker's Delight (2nd ed.) (Addison Wesley, 2013), 173-174 but adapted for signed longs.
1317 inline int64_t multiply_high_signed(const int64_t x, const int64_t y) {
1318   const jlong x1 = java_shift_right((jlong)x, 32);
1319   const jlong x2 = x & 0xFFFFFFFF;
1320   const jlong y1 = java_shift_right((jlong)y, 32);
1321   const jlong y2 = y & 0xFFFFFFFF;
1322 
1323   const uint64_t z2 = (uint64_t)x2 * y2;
1324   const int64_t t = x1 * y2 + (z2 >> 32u); // Unsigned shift
1325   int64_t z1 = t & 0xFFFFFFFF;
1326   const int64_t z0 = java_shift_right((jlong)t, 32);
1327   z1 += x2 * y1;
1328 
1329   return x1 * y1 + z0 + java_shift_right((jlong)z1, 32);
1330 }
1331 
1332 // Dereference vptr
1333 // All C++ compilers that we know of have the vtbl pointer in the first
1334 // word.  If there are exceptions, this function needs to be made compiler
1335 // specific.
1336 static inline void* dereference_vptr(const void* addr) {
1337   return *(void**)addr;
1338 }
1339 
1340 //----------------------------------------------------------------------------------------------------
1341 // String type aliases used by command line flag declarations and
1342 // processing utilities.
1343 
1344 typedef const char* ccstr;
1345 typedef const char* ccstrlist;   // represents string arguments which accumulate
1346 
1347 //----------------------------------------------------------------------------------------------------
1348 // Default hash/equals functions used by ResourceHashtable
1349 
1350 template<typename K> unsigned primitive_hash(const K& k) {
1351   unsigned hash = (unsigned)((uintptr_t)k);
1352   return hash ^ (hash >> 3); // just in case we're dealing with aligned ptrs
1353 }
1354 
1355 template<typename K> bool primitive_equals(const K& k0, const K& k1) {
1356   return k0 == k1;
1357 }
1358 
1359 //----------------------------------------------------------------------------------------------------
1360 
1361 // Allow use of C++ thread_local when approved - see JDK-8282469.
1362 #define APPROVED_CPP_THREAD_LOCAL thread_local
1363 
1364 // Converts any type T to a reference type.
1365 template<typename T>
1366 std::add_rvalue_reference_t<T> declval() noexcept;
1367 
1368 #endif // SHARE_UTILITIES_GLOBALDEFINITIONS_HPP