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 #include "precompiled.hpp"
 26 #include "runtime/globals.hpp"
 27 #include "runtime/os.hpp"
 28 #include "runtime/signature.hpp"
 29 #include "utilities/globalDefinitions.hpp"
 30 #include "utilities/powerOfTwo.hpp"
 31 
 32 // Basic error support
 33 
 34 // Info for oops within a java object.  Defaults are zero so
 35 // things will break badly if incorrectly initialized.
 36 int heapOopSize        = 0;
 37 int LogBytesPerHeapOop = 0;
 38 int LogBitsPerHeapOop  = 0;
 39 int BytesPerHeapOop    = 0;
 40 int BitsPerHeapOop     = 0;
 41 
 42 // Old CDS options
 43 bool DumpSharedSpaces;
 44 bool DynamicDumpSharedSpaces;
 45 bool RequireSharedSpaces;
 46 extern "C" {
 47 JNIEXPORT jboolean UseSharedSpaces = true;
 48 }
 49 
 50 // Object alignment, in units of HeapWords.
 51 // Defaults are -1 so things will break badly if incorrectly initialized.
 52 int MinObjAlignment            = -1;
 53 int MinObjAlignmentInBytes     = -1;
 54 int MinObjAlignmentInBytesMask = 0;
 55 
 56 int LogMinObjAlignment         = -1;
 57 int LogMinObjAlignmentInBytes  = -1;
 58 
 59 // Oop encoding heap max
 60 uint64_t OopEncodingHeapMax = 0;
 61 
 62 // Something to help porters sleep at night
 63 
 64 #ifdef ASSERT
 65 BasicType char2type(int ch) {
 66   switch (ch) {
 67 #define EACH_SIG(ch, bt, ignore) \
 68     case ch: return bt;
 69     SIGNATURE_TYPES_DO(EACH_SIG, ignore)
 70 #undef EACH_SIG
 71   }
 72   return T_ILLEGAL;
 73 }
 74 
 75 extern bool signature_constants_sane();
 76 #endif //ASSERT
 77 
 78 void basic_types_init() {
 79 #ifdef ASSERT
 80 #ifdef _LP64
 81   static_assert(min_intx ==  (intx)CONST64(0x8000000000000000), "correct constant");
 82   static_assert(max_intx ==  CONST64(0x7FFFFFFFFFFFFFFF), "correct constant");
 83   static_assert(max_uintx == CONST64(0xFFFFFFFFFFFFFFFF), "correct constant");
 84   static_assert( 8 == sizeof( intx),      "wrong size for basic type");
 85   static_assert( 8 == sizeof( jobject),   "wrong size for basic type");
 86 #else
 87   static_assert(min_intx ==  (intx)0x80000000,  "correct constant");
 88   static_assert(max_intx ==  0x7FFFFFFF,  "correct constant");
 89   static_assert(max_uintx == 0xFFFFFFFF,  "correct constant");
 90   static_assert( 4 == sizeof( intx),      "wrong size for basic type");
 91   static_assert( 4 == sizeof( jobject),   "wrong size for basic type");
 92 #endif
 93   static_assert( (~max_juint) == 0,  "max_juint has all its bits");
 94   static_assert( (~max_uintx) == 0,  "max_uintx has all its bits");
 95   static_assert( (~max_julong) == 0, "max_julong has all its bits");
 96   static_assert( 1 == sizeof( jbyte),     "wrong size for basic type");
 97   static_assert( 2 == sizeof( jchar),     "wrong size for basic type");
 98   static_assert( 2 == sizeof( jshort),    "wrong size for basic type");
 99   static_assert( 4 == sizeof( juint),     "wrong size for basic type");
100   static_assert( 4 == sizeof( jint),      "wrong size for basic type");
101   static_assert( 1 == sizeof( jboolean),  "wrong size for basic type");
102   static_assert( 8 == sizeof( jlong),     "wrong size for basic type");
103   static_assert( 4 == sizeof( jfloat),    "wrong size for basic type");
104   static_assert( 8 == sizeof( jdouble),   "wrong size for basic type");
105   static_assert( 1 == sizeof( u1),        "wrong size for basic type");
106   static_assert( 2 == sizeof( u2),        "wrong size for basic type");
107   static_assert( 4 == sizeof( u4),        "wrong size for basic type");
108   static_assert(wordSize == BytesPerWord, "should be the same since they're used interchangeably");
109   static_assert(wordSize == HeapWordSize, "should be the same since they're also used interchangeably");
110 
111   assert(signature_constants_sane(), "");
112 
113   int num_type_chars = 0;
114   for (int i = 0; i < 99; i++) {
115     if (type2char((BasicType)i) != 0) {
116       assert(char2type(type2char((BasicType)i)) == i, "proper inverses");
117       assert(Signature::basic_type(type2char((BasicType)i)) == i, "proper inverses");
118       num_type_chars++;
119     }
120   }
121   assert(num_type_chars == 11, "must have tested the right number of mappings");
122   assert(char2type(0) == T_ILLEGAL, "correct illegality");
123 
124   {
125     for (int i = T_BOOLEAN; i <= T_CONFLICT; i++) {
126       BasicType vt = (BasicType)i;
127       BasicType ft = type2field[vt];
128       switch (vt) {
129       // the following types might plausibly show up in memory layouts:
130       case T_BOOLEAN:
131       case T_BYTE:
132       case T_CHAR:
133       case T_SHORT:
134       case T_INT:
135       case T_FLOAT:
136       case T_DOUBLE:
137       case T_LONG:
138       case T_OBJECT:
139       case T_ADDRESS:     // random raw pointer
140       case T_METADATA:    // metadata pointer
141       case T_NARROWOOP:   // compressed pointer
142       case T_NARROWKLASS: // compressed klass pointer
143       case T_CONFLICT:    // might as well support a bottom type
144       case T_VOID:        // padding or other unaddressed word
145         // layout type must map to itself
146         assert(vt == ft, "");
147         break;
148       default:
149         // non-layout type must map to a (different) layout type
150         assert(vt != ft, "");
151         assert(ft == type2field[ft], "");
152       }
153       // every type must map to same-sized layout type:
154       assert(type2size[vt] == type2size[ft], "");
155     }
156   }
157   // These are assumed, e.g., when filling HeapWords with juints.
158   static_assert(is_power_of_2(sizeof(juint)), "juint must be power of 2");
159   static_assert(is_power_of_2(HeapWordSize), "HeapWordSize must be power of 2");
160   static_assert((size_t)HeapWordSize >= sizeof(juint),
161                 "HeapWord should be at least as large as juint");
162   static_assert(sizeof(NULL) == sizeof(char*), "NULL must be same size as pointer");
163 #endif
164 
165   if( JavaPriority1_To_OSPriority != -1 )
166     os::java_to_os_priority[1] = JavaPriority1_To_OSPriority;
167   if( JavaPriority2_To_OSPriority != -1 )
168     os::java_to_os_priority[2] = JavaPriority2_To_OSPriority;
169   if( JavaPriority3_To_OSPriority != -1 )
170     os::java_to_os_priority[3] = JavaPriority3_To_OSPriority;
171   if( JavaPriority4_To_OSPriority != -1 )
172     os::java_to_os_priority[4] = JavaPriority4_To_OSPriority;
173   if( JavaPriority5_To_OSPriority != -1 )
174     os::java_to_os_priority[5] = JavaPriority5_To_OSPriority;
175   if( JavaPriority6_To_OSPriority != -1 )
176     os::java_to_os_priority[6] = JavaPriority6_To_OSPriority;
177   if( JavaPriority7_To_OSPriority != -1 )
178     os::java_to_os_priority[7] = JavaPriority7_To_OSPriority;
179   if( JavaPriority8_To_OSPriority != -1 )
180     os::java_to_os_priority[8] = JavaPriority8_To_OSPriority;
181   if( JavaPriority9_To_OSPriority != -1 )
182     os::java_to_os_priority[9] = JavaPriority9_To_OSPriority;
183   if(JavaPriority10_To_OSPriority != -1 )
184     os::java_to_os_priority[10] = JavaPriority10_To_OSPriority;
185 
186   // Set the size of basic types here (after argument parsing but before
187   // stub generation).
188   if (UseCompressedOops) {
189     // Size info for oops within java objects is fixed
190     heapOopSize        = jintSize;
191     LogBytesPerHeapOop = LogBytesPerInt;
192     LogBitsPerHeapOop  = LogBitsPerInt;
193     BytesPerHeapOop    = BytesPerInt;
194     BitsPerHeapOop     = BitsPerInt;
195   } else {
196     heapOopSize        = oopSize;
197     LogBytesPerHeapOop = LogBytesPerWord;
198     LogBitsPerHeapOop  = LogBitsPerWord;
199     BytesPerHeapOop    = BytesPerWord;
200     BitsPerHeapOop     = BitsPerWord;
201   }
202   _type2aelembytes[T_OBJECT] = heapOopSize;
203   _type2aelembytes[T_ARRAY]  = heapOopSize;
204 }
205 
206 
207 // Map BasicType to signature character
208 char type2char_tab[T_CONFLICT+1] = {
209   0, 0, 0, 0,
210   JVM_SIGNATURE_BOOLEAN, JVM_SIGNATURE_CHAR,
211   JVM_SIGNATURE_FLOAT,   JVM_SIGNATURE_DOUBLE,
212   JVM_SIGNATURE_BYTE,    JVM_SIGNATURE_SHORT,
213   JVM_SIGNATURE_INT,     JVM_SIGNATURE_LONG,
214   JVM_SIGNATURE_CLASS,   JVM_SIGNATURE_ARRAY,
215   JVM_SIGNATURE_VOID,    0,
216   0, 0, 0, 0
217 };
218 
219 // Map BasicType to Java type name
220 const char* type2name_tab[T_CONFLICT+1] = {
221   nullptr, nullptr, nullptr, nullptr,
222   "boolean",
223   "char",
224   "float",
225   "double",
226   "byte",
227   "short",
228   "int",
229   "long",
230   "object",
231   "array",
232   "void",
233   "*address*",
234   "*narrowoop*",
235   "*metadata*",
236   "*narrowklass*",
237   "*conflict*"
238 };
239 const char* type2name(BasicType t) {
240   if (t < ARRAY_SIZE(type2name_tab)) {
241     return type2name_tab[t];
242   } else if (t == T_ILLEGAL) {
243     return "*illegal*";
244   } else {
245     fatal("invalid type %d", t);
246     return "invalid type";
247   }
248 }
249 
250 
251 
252 BasicType name2type(const char* name) {
253   for (int i = T_BOOLEAN; i <= T_VOID; i++) {
254     BasicType t = (BasicType)i;
255     if (type2name_tab[t] != nullptr && 0 == strcmp(type2name_tab[t], name))
256       return t;
257   }
258   return T_ILLEGAL;
259 }
260 
261 // Map BasicType to size in words
262 int type2size[T_CONFLICT+1]={ -1, 0, 0, 0, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 0, 1, 1, 1, 1, -1};
263 
264 BasicType type2field[T_CONFLICT+1] = {
265   (BasicType)0,            // 0,
266   (BasicType)0,            // 1,
267   (BasicType)0,            // 2,
268   (BasicType)0,            // 3,
269   T_BOOLEAN,               // T_BOOLEAN  =  4,
270   T_CHAR,                  // T_CHAR     =  5,
271   T_FLOAT,                 // T_FLOAT    =  6,
272   T_DOUBLE,                // T_DOUBLE   =  7,
273   T_BYTE,                  // T_BYTE     =  8,
274   T_SHORT,                 // T_SHORT    =  9,
275   T_INT,                   // T_INT      = 10,
276   T_LONG,                  // T_LONG     = 11,
277   T_OBJECT,                // T_OBJECT   = 12,
278   T_OBJECT,                // T_ARRAY    = 13,
279   T_VOID,                  // T_VOID     = 14,
280   T_ADDRESS,               // T_ADDRESS  = 15,
281   T_NARROWOOP,             // T_NARROWOOP= 16,
282   T_METADATA,              // T_METADATA = 17,
283   T_NARROWKLASS,           // T_NARROWKLASS = 18,
284   T_CONFLICT               // T_CONFLICT = 19,
285 };
286 
287 
288 BasicType type2wfield[T_CONFLICT+1] = {
289   (BasicType)0,            // 0,
290   (BasicType)0,            // 1,
291   (BasicType)0,            // 2,
292   (BasicType)0,            // 3,
293   T_INT,     // T_BOOLEAN  =  4,
294   T_INT,     // T_CHAR     =  5,
295   T_FLOAT,   // T_FLOAT    =  6,
296   T_DOUBLE,  // T_DOUBLE   =  7,
297   T_INT,     // T_BYTE     =  8,
298   T_INT,     // T_SHORT    =  9,
299   T_INT,     // T_INT      = 10,
300   T_LONG,    // T_LONG     = 11,
301   T_OBJECT,  // T_OBJECT   = 12,
302   T_OBJECT,  // T_ARRAY    = 13,
303   T_VOID,    // T_VOID     = 14,
304   T_ADDRESS, // T_ADDRESS  = 15,
305   T_NARROWOOP, // T_NARROWOOP  = 16,
306   T_METADATA,  // T_METADATA   = 17,
307   T_NARROWKLASS, // T_NARROWKLASS  = 18,
308   T_CONFLICT // T_CONFLICT = 19,
309 };
310 
311 
312 int _type2aelembytes[T_CONFLICT+1] = {
313   0,                         // 0
314   0,                         // 1
315   0,                         // 2
316   0,                         // 3
317   T_BOOLEAN_aelem_bytes,     // T_BOOLEAN  =  4,
318   T_CHAR_aelem_bytes,        // T_CHAR     =  5,
319   T_FLOAT_aelem_bytes,       // T_FLOAT    =  6,
320   T_DOUBLE_aelem_bytes,      // T_DOUBLE   =  7,
321   T_BYTE_aelem_bytes,        // T_BYTE     =  8,
322   T_SHORT_aelem_bytes,       // T_SHORT    =  9,
323   T_INT_aelem_bytes,         // T_INT      = 10,
324   T_LONG_aelem_bytes,        // T_LONG     = 11,
325   T_OBJECT_aelem_bytes,      // T_OBJECT   = 12,
326   T_ARRAY_aelem_bytes,       // T_ARRAY    = 13,
327   0,                         // T_VOID     = 14,
328   T_OBJECT_aelem_bytes,      // T_ADDRESS  = 15,
329   T_NARROWOOP_aelem_bytes,   // T_NARROWOOP= 16,
330   T_OBJECT_aelem_bytes,      // T_METADATA = 17,
331   T_NARROWKLASS_aelem_bytes, // T_NARROWKLASS= 18,
332   0                          // T_CONFLICT = 19,
333 };
334 
335 #ifdef ASSERT
336 int type2aelembytes(BasicType t, bool allow_address) {
337   assert((allow_address || t != T_ADDRESS) && t <= T_CONFLICT, "unexpected basic type");
338   return _type2aelembytes[t];
339 }
340 #endif
341 
342 // Support for 64-bit integer arithmetic
343 
344 // The following code is mostly taken from JVM typedefs_md.h and system_md.c
345 
346 static const jlong high_bit   = (jlong)1 << (jlong)63;
347 static const jlong other_bits = ~high_bit;
348 
349 jlong float2long(jfloat f) {
350   jlong tmp = (jlong) f;
351   if (tmp != high_bit) {
352     return tmp;
353   } else {
354     if (g_isnan((jdouble)f)) {
355       return 0;
356     }
357     if (f < 0) {
358       return high_bit;
359     } else {
360       return other_bits;
361     }
362   }
363 }
364 
365 
366 jlong double2long(jdouble f) {
367   jlong tmp = (jlong) f;
368   if (tmp != high_bit) {
369     return tmp;
370   } else {
371     if (g_isnan(f)) {
372       return 0;
373     }
374     if (f < 0) {
375       return high_bit;
376     } else {
377       return other_bits;
378     }
379   }
380 }
381 
382 // least common multiple
383 size_t lcm(size_t a, size_t b) {
384     size_t cur, div, next;
385 
386     cur = MAX2(a, b);
387     div = MIN2(a, b);
388 
389     assert(div != 0, "lcm requires positive arguments");
390 
391 
392     while ((next = cur % div) != 0) {
393         cur = div; div = next;
394     }
395 
396 
397     julong result = julong(a) * b / div;
398     assert(result <= (size_t)max_uintx, "Integer overflow in lcm");
399 
400     return size_t(result);
401 }
402 
403 
404 // Test that nth_bit macro and friends behave as
405 // expected, even with low-precedence operators.
406 
407 STATIC_ASSERT(nth_bit(3)   == 0x8);
408 STATIC_ASSERT(nth_bit(1|2) == 0x8);
409 
410 STATIC_ASSERT(right_n_bits(3)   == 0x7);
411 STATIC_ASSERT(right_n_bits(1|2) == 0x7);