1 /*
2 * Copyright (c) 1997, 2025, 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 "runtime/globals.hpp"
26 #include "runtime/os.hpp"
27 #include "runtime/signature.hpp"
28 #include "utilities/globalDefinitions.hpp"
29 #include "utilities/powerOfTwo.hpp"
30
31 // Basic error support
32
33 // Info for oops within a java object. Defaults are zero so
34 // things will break badly if incorrectly initialized.
35 int heapOopSize = 0;
36 int LogBytesPerHeapOop = 0;
37 int LogBitsPerHeapOop = 0;
38 int BytesPerHeapOop = 0;
39 int BitsPerHeapOop = 0;
40
41 // Old CDS options
42 bool RequireSharedSpaces;
43 extern "C" {
44 JNIEXPORT jboolean UseSharedSpaces = true;
45 }
46
47 // Object alignment, in units of HeapWords.
48 // Defaults are -1 so things will break badly if incorrectly initialized.
49 int MinObjAlignment = -1;
50 int MinObjAlignmentInBytes = -1;
51 int MinObjAlignmentInBytesMask = 0;
52
53 int LogMinObjAlignment = -1;
54 int LogMinObjAlignmentInBytes = -1;
55
56 // Oop encoding heap max
57 uint64_t OopEncodingHeapMax = 0;
58
59 // Something to help porters sleep at night
60
61 #ifdef ASSERT
62 static BasicType char2type(int ch) {
63 switch (ch) {
64 #define EACH_SIG(ch, bt, ignore) \
65 case ch: return bt;
66 SIGNATURE_TYPES_DO(EACH_SIG, ignore)
67 #undef EACH_SIG
68 }
69 return T_ILLEGAL;
70 }
71
72 extern bool signature_constants_sane();
73 #endif //ASSERT
74
75 void basic_types_init() {
76 #ifdef ASSERT
77 #ifdef _LP64
78 static_assert(min_intx == (intx)CONST64(0x8000000000000000), "correct constant");
79 static_assert(max_intx == CONST64(0x7FFFFFFFFFFFFFFF), "correct constant");
80 static_assert(max_uintx == CONST64(0xFFFFFFFFFFFFFFFF), "correct constant");
81 static_assert( 8 == sizeof( intx), "wrong size for basic type");
82 static_assert( 8 == sizeof( jobject), "wrong size for basic type");
83 #else
84 static_assert(min_intx == (intx)0x80000000, "correct constant");
85 static_assert(max_intx == 0x7FFFFFFF, "correct constant");
86 static_assert(max_uintx == 0xFFFFFFFF, "correct constant");
87 static_assert( 4 == sizeof( intx), "wrong size for basic type");
88 static_assert( 4 == sizeof( jobject), "wrong size for basic type");
89 #endif
90 static_assert( (~max_juint) == 0, "max_juint has all its bits");
91 static_assert( (~max_uintx) == 0, "max_uintx has all its bits");
92 static_assert( (~max_julong) == 0, "max_julong has all its bits");
93 static_assert( 1 == sizeof( jbyte), "wrong size for basic type");
94 static_assert( 2 == sizeof( jchar), "wrong size for basic type");
95 static_assert( 2 == sizeof( jshort), "wrong size for basic type");
96 static_assert( 4 == sizeof( juint), "wrong size for basic type");
97 static_assert( 4 == sizeof( jint), "wrong size for basic type");
98 static_assert( 1 == sizeof( jboolean), "wrong size for basic type");
99 static_assert( 8 == sizeof( jlong), "wrong size for basic type");
100 static_assert( 4 == sizeof( jfloat), "wrong size for basic type");
101 static_assert( 8 == sizeof( jdouble), "wrong size for basic type");
102 static_assert( 1 == sizeof( u1), "wrong size for basic type");
103 static_assert( 2 == sizeof( u2), "wrong size for basic type");
104 static_assert( 4 == sizeof( u4), "wrong size for basic type");
105 static_assert(wordSize == BytesPerWord, "should be the same since they're used interchangeably");
106 static_assert(wordSize == HeapWordSize, "should be the same since they're also used interchangeably");
107
108 assert(signature_constants_sane(), "");
109
110 int num_type_chars = 0;
111 for (int i = 0; i < 99; i++) {
112 if (type2char((BasicType)i) != 0) {
113 assert(char2type(type2char((BasicType)i)) == i, "proper inverses");
114 assert(Signature::basic_type(type2char((BasicType)i)) == i, "proper inverses");
115 num_type_chars++;
116 }
117 }
118 assert(num_type_chars == 12, "must have tested the right number of mappings");
119 assert(char2type(0) == T_ILLEGAL, "correct illegality");
120
121 {
122 for (int i = T_BOOLEAN; i <= T_CONFLICT; i++) {
123 BasicType vt = (BasicType)i;
124 BasicType ft = type2field[vt];
125 switch (vt) {
126 // the following types might plausibly show up in memory layouts:
127 case T_BOOLEAN:
128 case T_BYTE:
129 case T_CHAR:
130 case T_SHORT:
131 case T_INT:
132 case T_FLOAT:
133 case T_DOUBLE:
134 case T_LONG:
135 case T_OBJECT:
136 case T_ADDRESS: // random raw pointer
137 case T_METADATA: // metadata pointer
138 case T_NARROWOOP: // compressed pointer
139 case T_NARROWKLASS: // compressed klass pointer
140 case T_CONFLICT: // might as well support a bottom type
141 case T_VOID: // padding or other unaddressed word
142 // layout type must map to itself
143 assert(vt == ft, "");
144 break;
145 default:
146 // non-layout type must map to a (different) layout type
147 assert(vt != ft, "");
148 assert(ft == type2field[ft], "");
149 }
150 // every type must map to same-sized layout type:
151 assert(type2size[vt] == type2size[ft], "");
152 }
153 }
154 // These are assumed, e.g., when filling HeapWords with juints.
155 static_assert(is_power_of_2(sizeof(juint)), "juint must be power of 2");
156 static_assert(is_power_of_2(HeapWordSize), "HeapWordSize must be power of 2");
157 static_assert((size_t)HeapWordSize >= sizeof(juint),
158 "HeapWord should be at least as large as juint");
159 #endif
160
161 if( JavaPriority1_To_OSPriority != -1 )
162 os::java_to_os_priority[1] = JavaPriority1_To_OSPriority;
163 if( JavaPriority2_To_OSPriority != -1 )
164 os::java_to_os_priority[2] = JavaPriority2_To_OSPriority;
165 if( JavaPriority3_To_OSPriority != -1 )
166 os::java_to_os_priority[3] = JavaPriority3_To_OSPriority;
167 if( JavaPriority4_To_OSPriority != -1 )
168 os::java_to_os_priority[4] = JavaPriority4_To_OSPriority;
169 if( JavaPriority5_To_OSPriority != -1 )
170 os::java_to_os_priority[5] = JavaPriority5_To_OSPriority;
171 if( JavaPriority6_To_OSPriority != -1 )
172 os::java_to_os_priority[6] = JavaPriority6_To_OSPriority;
173 if( JavaPriority7_To_OSPriority != -1 )
174 os::java_to_os_priority[7] = JavaPriority7_To_OSPriority;
175 if( JavaPriority8_To_OSPriority != -1 )
176 os::java_to_os_priority[8] = JavaPriority8_To_OSPriority;
177 if( JavaPriority9_To_OSPriority != -1 )
178 os::java_to_os_priority[9] = JavaPriority9_To_OSPriority;
179 if(JavaPriority10_To_OSPriority != -1 )
180 os::java_to_os_priority[10] = JavaPriority10_To_OSPriority;
181
182 // Set the size of basic types here (after argument parsing but before
183 // stub generation).
184 if (UseCompressedOops) {
185 // Size info for oops within java objects is fixed
186 heapOopSize = jintSize;
187 LogBytesPerHeapOop = LogBytesPerInt;
188 LogBitsPerHeapOop = LogBitsPerInt;
189 BytesPerHeapOop = BytesPerInt;
190 BitsPerHeapOop = BitsPerInt;
191 } else {
192 heapOopSize = oopSize;
193 LogBytesPerHeapOop = LogBytesPerWord;
194 LogBitsPerHeapOop = LogBitsPerWord;
195 BytesPerHeapOop = BytesPerWord;
196 BitsPerHeapOop = BitsPerWord;
197 }
198 _type2aelembytes[T_OBJECT] = heapOopSize;
199 _type2aelembytes[T_ARRAY] = heapOopSize;
200 _type2aelembytes[T_FLAT_ELEMENT] = heapOopSize;
201 }
202
203
204 // Map BasicType to signature character
205 char type2char_tab[T_CONFLICT+1] = {
206 0, 0, 0, 0,
207 JVM_SIGNATURE_BOOLEAN, JVM_SIGNATURE_CHAR,
208 JVM_SIGNATURE_FLOAT, JVM_SIGNATURE_DOUBLE,
209 JVM_SIGNATURE_BYTE, JVM_SIGNATURE_SHORT,
210 JVM_SIGNATURE_INT, JVM_SIGNATURE_LONG,
211 JVM_SIGNATURE_CLASS, JVM_SIGNATURE_ARRAY,
212 JVM_SIGNATURE_FLAT_ELEMENT, JVM_SIGNATURE_VOID,
213 0, 0, 0, 0, 0
214 };
215
216 // Map BasicType to Java type name
217 const char* type2name_tab[T_CONFLICT+1] = {
218 nullptr, nullptr, nullptr, nullptr,
219 "boolean",
220 "char",
221 "float",
222 "double",
223 "byte",
224 "short",
225 "int",
226 "long",
227 "object",
228 "array",
229 "inline_type",
230 "void",
231 "*address*",
232 "*narrowoop*",
233 "*metadata*",
234 "*narrowklass*",
235 "*conflict*"
236 };
237 const char* type2name(BasicType t) {
238 if (t < ARRAY_SIZE(type2name_tab)) {
239 return type2name_tab[t];
240 } else if (t == T_ILLEGAL) {
241 return "*illegal*";
242 } else {
243 fatal("invalid type %d", t);
244 return "invalid type";
245 }
246 }
247
248
249
250 BasicType name2type(const char* name) {
251 for (int i = T_BOOLEAN; i <= T_VOID; i++) {
252 BasicType t = (BasicType)i;
253 if (type2name_tab[t] != nullptr && 0 == strcmp(type2name_tab[t], name))
254 return t;
255 }
256 return T_ILLEGAL;
257 }
258
259 // Map BasicType to size in words
260 int type2size[T_CONFLICT+1]={ -1, 0, 0, 0, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 0, 1, 1, 1, 1, -1};
261
262 BasicType type2field[T_CONFLICT+1] = {
263 (BasicType)0, // 0,
264 (BasicType)0, // 1,
265 (BasicType)0, // 2,
266 (BasicType)0, // 3,
267 T_BOOLEAN, // T_BOOLEAN = 4,
268 T_CHAR, // T_CHAR = 5,
269 T_FLOAT, // T_FLOAT = 6,
270 T_DOUBLE, // T_DOUBLE = 7,
271 T_BYTE, // T_BYTE = 8,
272 T_SHORT, // T_SHORT = 9,
273 T_INT, // T_INT = 10,
274 T_LONG, // T_LONG = 11,
275 T_OBJECT, // T_OBJECT = 12,
276 T_OBJECT, // T_ARRAY = 13,
277 T_OBJECT, // T_PRIMITIVE_OBJECT = 14,
278 T_VOID, // T_VOID = 15,
279 T_ADDRESS, // T_ADDRESS = 16,
280 T_NARROWOOP, // T_NARROWOOP= 17,
281 T_METADATA, // T_METADATA = 18,
282 T_NARROWKLASS, // T_NARROWKLASS = 19,
283 T_CONFLICT // T_CONFLICT = 20
284 };
285
286
287 BasicType type2wfield[T_CONFLICT+1] = {
288 (BasicType)0, // 0,
289 (BasicType)0, // 1,
290 (BasicType)0, // 2,
291 (BasicType)0, // 3,
292 T_INT, // T_BOOLEAN = 4,
293 T_INT, // T_CHAR = 5,
294 T_FLOAT, // T_FLOAT = 6,
295 T_DOUBLE, // T_DOUBLE = 7,
296 T_INT, // T_BYTE = 8,
297 T_INT, // T_SHORT = 9,
298 T_INT, // T_INT = 10,
299 T_LONG, // T_LONG = 11,
300 T_OBJECT, // T_OBJECT = 12,
301 T_OBJECT, // T_ARRAY = 13,
302 T_OBJECT, // T_PRIMITIVE_OBJECT = 14,
303 T_VOID, // T_VOID = 15,
304 T_ADDRESS, // T_ADDRESS = 16,
305 T_NARROWOOP, // T_NARROWOOP = 17,
306 T_METADATA, // T_METADATA = 18,
307 T_NARROWKLASS, // T_NARROWKLASS = 19,
308 T_CONFLICT // T_CONFLICT = 20
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 T_FLAT_ELEMENT_aelem_bytes, // T_PRIMITIVE_OBJECT = 14,
328 0, // T_VOID = 15,
329 T_OBJECT_aelem_bytes, // T_ADDRESS = 16,
330 T_NARROWOOP_aelem_bytes, // T_NARROWOOP= 17,
331 T_OBJECT_aelem_bytes, // T_METADATA = 18,
332 T_NARROWKLASS_aelem_bytes, // T_NARROWKLASS= 19,
333 0 // T_CONFLICT = 20
334 };
335
336 #ifdef ASSERT
337 int type2aelembytes(BasicType t, bool allow_address) {
338 assert((allow_address || t != T_ADDRESS) && t <= T_CONFLICT, "unexpected basic type");
339 return _type2aelembytes[t];
340 }
341 #endif
342
343 // Support for 64-bit integer arithmetic
344
345 // The following code is mostly taken from JVM typedefs_md.h and system_md.c
346
347 static const jlong high_bit = (jlong)1 << (jlong)63;
348 static const jlong other_bits = ~high_bit;
349
350 jlong float2long(jfloat f) {
351 jlong tmp = (jlong) f;
352 if (tmp != high_bit) {
353 return tmp;
354 } else {
355 if (g_isnan((jdouble)f)) {
356 return 0;
357 }
358 if (f < 0) {
359 return high_bit;
360 } else {
361 return other_bits;
362 }
363 }
364 }
365
366
367 jlong double2long(jdouble f) {
368 jlong tmp = (jlong) f;
369 if (tmp != high_bit) {
370 return tmp;
371 } else {
372 if (g_isnan(f)) {
373 return 0;
374 }
375 if (f < 0) {
376 return high_bit;
377 } else {
378 return other_bits;
379 }
380 }
381 }
382
383 // least common multiple
384 size_t lcm(size_t a, size_t b) {
385 size_t cur, div, next;
386
387 cur = MAX2(a, b);
388 div = MIN2(a, b);
389
390 assert(div != 0, "lcm requires positive arguments");
391
392
393 while ((next = cur % div) != 0) {
394 cur = div; div = next;
395 }
396
397
398 julong result = julong(a) * b / div;
399 assert(result <= (size_t)max_uintx, "Integer overflow in lcm");
400
401 return size_t(result);
402 }
403
404
405 // Test that nth_bit macro and friends behave as
406 // expected, even with low-precedence operators.
407
408 STATIC_ASSERT(nth_bit(3) == 0x8);
409 STATIC_ASSERT(nth_bit(1|2) == 0x8);
410
411 STATIC_ASSERT(right_n_bits(3) == 0x7);
412 STATIC_ASSERT(right_n_bits(1|2) == 0x7);
413
414 // Check for Flush-To-Zero mode
415
416 // On some processors faster execution can be achieved by setting a
417 // mode to return zero for extremely small results, rather than an
418 // IEEE-754 subnormal number. This mode is not compatible with the
419 // Java Language Standard.
420
421 // We need the addition of _large_subnormal and _small_subnormal to be
422 // performed at runtime. _small_subnormal is volatile so that
423 // expressions involving it cannot be evaluated at compile time.
424 static const double large_subnormal_double
425 = jdouble_cast(0x0030000000000000); // 0x1.0p-1020;
426 static const volatile double small_subnormal_double
427 = jdouble_cast(0x0000000000000003); // 0x0.0000000000003p-1022;
428
429 // Quickly test to make sure IEEE-754 subnormal numbers are correctly
430 // handled.
431 bool IEEE_subnormal_handling_OK() {
432 // _small_subnormal is the smallest subnormal number that has two
433 // bits set. _large_subnormal is a number such that, when
434 // _small_subnormal is added to it, must be rounded according to the
435 // mode. These two tests detect the rounding mode in use. If
436 // subnormals are turned off (i.e. subnormals-are-zero) flush-to-
437 // zero mode is in use.
438
439 return (large_subnormal_double + small_subnormal_double > large_subnormal_double
440 && -large_subnormal_double - small_subnormal_double < -large_subnormal_double);
441 }