1 /*
2 * Copyright (c) 1999, 2024, Oracle and/or its affiliates. All rights reserved.
3 * Copyright (c) 2014, Red Hat Inc. All rights reserved.
4 * Copyright (c) 2020, 2022, Huawei Technologies Co., Ltd. All rights reserved.
5 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
6 *
7 * This code is free software; you can redistribute it and/or modify it
8 * under the terms of the GNU General Public License version 2 only, as
9 * published by the Free Software Foundation.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 *
25 */
26
27 #include "precompiled.hpp"
28 #include "c1/c1_LIR.hpp"
29 #include "c1/c1_MacroAssembler.hpp"
30 #include "c1/c1_Runtime1.hpp"
31 #include "classfile/systemDictionary.hpp"
32 #include "gc/shared/barrierSetAssembler.hpp"
33 #include "gc/shared/collectedHeap.hpp"
34 #include "interpreter/interpreter.hpp"
35 #include "oops/arrayOop.hpp"
36 #include "oops/markWord.hpp"
37 #include "runtime/basicLock.hpp"
38 #include "runtime/os.hpp"
39 #include "runtime/sharedRuntime.hpp"
40 #include "runtime/stubRoutines.hpp"
41
42 void C1_MacroAssembler::float_cmp(bool is_float, int unordered_result,
43 FloatRegister freg0, FloatRegister freg1,
44 Register result) {
45 if (is_float) {
46 float_compare(result, freg0, freg1, unordered_result);
47 } else {
48 double_compare(result, freg0, freg1, unordered_result);
49 }
50 }
51
52 int C1_MacroAssembler::lock_object(Register hdr, Register obj, Register disp_hdr, Register temp, Label& slow_case) {
53 const int aligned_mask = BytesPerWord - 1;
54 const int hdr_offset = oopDesc::mark_offset_in_bytes();
55 assert_different_registers(hdr, obj, disp_hdr, temp, t0, t1);
56 int null_check_offset = -1;
57
58 verify_oop(obj);
59
60 // save object being locked into the BasicObjectLock
61 sd(obj, Address(disp_hdr, BasicObjectLock::obj_offset()));
62
63 null_check_offset = offset();
64
65 if (DiagnoseSyncOnValueBasedClasses != 0) {
66 load_klass(hdr, obj);
67 lwu(hdr, Address(hdr, Klass::access_flags_offset()));
68 test_bit(temp, hdr, exact_log2(JVM_ACC_IS_VALUE_BASED_CLASS));
69 bnez(temp, slow_case, true /* is_far */);
70 }
71
72 if (LockingMode == LM_LIGHTWEIGHT) {
73 lightweight_lock(obj, hdr, temp, t1, slow_case);
74 } else if (LockingMode == LM_LEGACY) {
75 Label done;
76 // Load object header
77 ld(hdr, Address(obj, hdr_offset));
78 // and mark it as unlocked
79 ori(hdr, hdr, markWord::unlocked_value);
80 // save unlocked object header into the displaced header location on the stack
81 sd(hdr, Address(disp_hdr, 0));
82 // test if object header is still the same (i.e. unlocked), and if so, store the
83 // displaced header address in the object header - if it is not the same, get the
84 // object header instead
85 la(temp, Address(obj, hdr_offset));
86 cmpxchgptr(hdr, disp_hdr, temp, t1, done, /*fallthough*/nullptr);
87 // if the object header was the same, we're done
88 // if the object header was not the same, it is now in the hdr register
89 // => test if it is a stack pointer into the same stack (recursive locking), i.e.:
90 //
91 // 1) (hdr & aligned_mask) == 0
92 // 2) sp <= hdr
93 // 3) hdr <= sp + page_size
94 //
95 // these 3 tests can be done by evaluating the following expression:
96 //
97 // (hdr -sp) & (aligned_mask - page_size)
98 //
99 // assuming both the stack pointer and page_size have their least
100 // significant 2 bits cleared and page_size is a power of 2
101 sub(hdr, hdr, sp);
102 mv(temp, aligned_mask - (int)os::vm_page_size());
103 andr(hdr, hdr, temp);
104 // for recursive locking, the result is zero => save it in the displaced header
105 // location (null in the displaced hdr location indicates recursive locking)
106 sd(hdr, Address(disp_hdr, 0));
107 // otherwise we don't care about the result and handle locking via runtime call
108 bnez(hdr, slow_case, /* is_far */ true);
109 // done
110 bind(done);
111 }
112
113 increment(Address(xthread, JavaThread::held_monitor_count_offset()));
114 return null_check_offset;
115 }
116
117 void C1_MacroAssembler::unlock_object(Register hdr, Register obj, Register disp_hdr, Register temp, Label& slow_case) {
118 const int aligned_mask = BytesPerWord - 1;
119 const int hdr_offset = oopDesc::mark_offset_in_bytes();
120 assert_different_registers(hdr, obj, disp_hdr, temp, t0, t1);
121 Label done;
122
123 if (LockingMode != LM_LIGHTWEIGHT) {
124 // load displaced header
125 ld(hdr, Address(disp_hdr, 0));
126 // if the loaded hdr is null we had recursive locking
127 // if we had recursive locking, we are done
128 beqz(hdr, done);
129 }
130
131 // load object
132 ld(obj, Address(disp_hdr, BasicObjectLock::obj_offset()));
133 verify_oop(obj);
134
135 if (LockingMode == LM_LIGHTWEIGHT) {
136 lightweight_unlock(obj, hdr, temp, t1, slow_case);
137 } else if (LockingMode == LM_LEGACY) {
138 // test if object header is pointing to the displaced header, and if so, restore
139 // the displaced header in the object - if the object header is not pointing to
140 // the displaced header, get the object header instead
141 // if the object header was not pointing to the displaced header,
142 // we do unlocking via runtime call
143 if (hdr_offset) {
144 la(temp, Address(obj, hdr_offset));
145 cmpxchgptr(disp_hdr, hdr, temp, t1, done, &slow_case);
146 } else {
147 cmpxchgptr(disp_hdr, hdr, obj, t1, done, &slow_case);
148 }
149 // done
150 bind(done);
151 }
152
153 decrement(Address(xthread, JavaThread::held_monitor_count_offset()));
154 }
155
156 // Defines obj, preserves var_size_in_bytes
157 void C1_MacroAssembler::try_allocate(Register obj, Register var_size_in_bytes, int con_size_in_bytes, Register tmp1, Register tmp2, Label& slow_case) {
158 if (UseTLAB) {
159 tlab_allocate(obj, var_size_in_bytes, con_size_in_bytes, tmp1, tmp2, slow_case, /* is_far */ true);
160 } else {
161 j(slow_case);
162 }
163 }
164
165 void C1_MacroAssembler::initialize_header(Register obj, Register klass, Register len, Register tmp1, Register tmp2) {
166 assert_different_registers(obj, klass, len, tmp1, tmp2);
167 // This assumes that all prototype bits fitr in an int32_t
168 mv(tmp1, (int32_t)(intptr_t)markWord::prototype().value());
169 sd(tmp1, Address(obj, oopDesc::mark_offset_in_bytes()));
170 // Todo UseCompactObjectHeaders
171 if (UseCompressedClassPointers) { // Take care not to kill klass
172 encode_klass_not_null(tmp1, klass, tmp2);
173 sw(tmp1, Address(obj, oopDesc::klass_offset_in_bytes()));
174 } else {
175 sd(klass, Address(obj, oopDesc::klass_offset_in_bytes()));
176 }
177
178 if (len->is_valid()) {
179 sw(len, Address(obj, arrayOopDesc::length_offset_in_bytes()));
180 int base_offset = arrayOopDesc::length_offset_in_bytes() + BytesPerInt;
181 if (!is_aligned(base_offset, BytesPerWord)) {
182 assert(is_aligned(base_offset, BytesPerInt), "must be 4-byte aligned");
183 // Clear gap/first 4 bytes following the length field.
184 sw(zr, Address(obj, base_offset));
185 }
186 } else if (UseCompressedClassPointers) {
187 store_klass_gap(obj, zr);
188 }
189 }
190
191 // preserves obj, destroys len_in_bytes
192 void C1_MacroAssembler::initialize_body(Register obj, Register len_in_bytes, int hdr_size_in_bytes, Register tmp) {
193 assert(hdr_size_in_bytes >= 0, "header size must be positive or 0");
194 Label done;
195
196 // len_in_bytes is positive and ptr sized
197 sub(len_in_bytes, len_in_bytes, hdr_size_in_bytes);
198 beqz(len_in_bytes, done);
199
200 // Preserve obj
201 if (hdr_size_in_bytes) {
202 add(obj, obj, hdr_size_in_bytes);
203 }
204 zero_memory(obj, len_in_bytes, tmp);
205 if (hdr_size_in_bytes) {
206 sub(obj, obj, hdr_size_in_bytes);
207 }
208
209 bind(done);
210 }
211
212 void C1_MacroAssembler::allocate_object(Register obj, Register tmp1, Register tmp2, int header_size, int object_size, Register klass, Label& slow_case) {
213 assert_different_registers(obj, tmp1, tmp2);
214 assert(header_size >= 0 && object_size >= header_size, "illegal sizes");
215
216 try_allocate(obj, noreg, object_size * BytesPerWord, tmp1, tmp2, slow_case);
217
218 initialize_object(obj, klass, noreg, object_size * HeapWordSize, tmp1, tmp2, UseTLAB);
219 }
220
221 void C1_MacroAssembler::initialize_object(Register obj, Register klass, Register var_size_in_bytes, int con_size_in_bytes, Register tmp1, Register tmp2, bool is_tlab_allocated) {
222 assert((con_size_in_bytes & MinObjAlignmentInBytesMask) == 0,
223 "con_size_in_bytes is not multiple of alignment");
224 const int hdr_size_in_bytes = instanceOopDesc::header_size() * HeapWordSize;
225
226 initialize_header(obj, klass, noreg, tmp1, tmp2);
227
228 if (!(UseTLAB && ZeroTLAB && is_tlab_allocated)) {
229 // clear rest of allocated space
230 const Register index = tmp2;
231 // 16: multiplier for threshold
232 const int threshold = 16 * BytesPerWord; // approximate break even point for code size (see comments below)
233 if (var_size_in_bytes != noreg) {
234 mv(index, var_size_in_bytes);
235 initialize_body(obj, index, hdr_size_in_bytes, tmp1);
236 } else if (con_size_in_bytes <= threshold) {
237 // use explicit null stores
238 int i = hdr_size_in_bytes;
239 if (i < con_size_in_bytes && (con_size_in_bytes % (2 * BytesPerWord))) { // 2: multiplier for BytesPerWord
240 sd(zr, Address(obj, i));
241 i += BytesPerWord;
242 }
243 for (; i < con_size_in_bytes; i += BytesPerWord) {
244 sd(zr, Address(obj, i));
245 }
246 } else if (con_size_in_bytes > hdr_size_in_bytes) {
247 block_comment("zero memory");
248 // use loop to null out the fields
249 int words = (con_size_in_bytes - hdr_size_in_bytes) / BytesPerWord;
250 mv(index, words / 8); // 8: byte size
251
252 const int unroll = 8; // Number of sd(zr) instructions we'll unroll
253 int remainder = words % unroll;
254 la(t0, Address(obj, hdr_size_in_bytes + remainder * BytesPerWord));
255
256 Label entry_point, loop;
257 j(entry_point);
258
259 bind(loop);
260 sub(index, index, 1);
261 for (int i = -unroll; i < 0; i++) {
262 if (-i == remainder) {
263 bind(entry_point);
264 }
265 sd(zr, Address(t0, i * wordSize));
266 }
267 if (remainder == 0) {
268 bind(entry_point);
269 }
270 add(t0, t0, unroll * wordSize);
271 bnez(index, loop);
272 }
273 }
274
275 membar(MacroAssembler::StoreStore);
276
277 if (CURRENT_ENV->dtrace_alloc_probes()) {
278 assert(obj == x10, "must be");
279 far_call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id)));
280 }
281
282 verify_oop(obj);
283 }
284
285 void C1_MacroAssembler::allocate_array(Register obj, Register len, Register tmp1, Register tmp2, int base_offset_in_bytes, int f, Register klass, Label& slow_case, bool zero_array) {
286 assert_different_registers(obj, len, tmp1, tmp2, klass);
287
288 // determine alignment mask
289 assert(!(BytesPerWord & 1), "must be multiple of 2 for masking code to work");
290
291 // check for negative or excessive length
292 mv(t0, (int32_t)max_array_allocation_length);
293 bgeu(len, t0, slow_case, /* is_far */ true);
294
295 const Register arr_size = tmp2; // okay to be the same
296 // align object end
297 mv(arr_size, (int32_t)base_offset_in_bytes + MinObjAlignmentInBytesMask);
298 shadd(arr_size, len, arr_size, t0, f);
299 andi(arr_size, arr_size, ~(uint)MinObjAlignmentInBytesMask);
300
301 try_allocate(obj, arr_size, 0, tmp1, tmp2, slow_case);
302
303 initialize_header(obj, klass, len, tmp1, tmp2);
304
305 // Align-up to word boundary, because we clear the 4 bytes potentially
306 // following the length field in initialize_header().
307 int base_offset = align_up(base_offset_in_bytes, BytesPerWord);
308
309 // clear rest of allocated space
310 const Register len_zero = len;
311 if (zero_array) {
312 initialize_body(obj, arr_size, base_offset, len_zero);
313 }
314
315 membar(MacroAssembler::StoreStore);
316
317 if (CURRENT_ENV->dtrace_alloc_probes()) {
318 assert(obj == x10, "must be");
319 far_call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id)));
320 }
321
322 verify_oop(obj);
323 }
324
325 void C1_MacroAssembler::build_frame(int framesize, int bang_size_in_bytes) {
326 assert(bang_size_in_bytes >= framesize, "stack bang size incorrect");
327 // Make sure there is enough stack space for this method's activation.
328 // Note that we do this before creating a frame.
329 generate_stack_overflow_check(bang_size_in_bytes);
330 MacroAssembler::build_frame(framesize);
331
332 // Insert nmethod entry barrier into frame.
333 BarrierSetAssembler* bs = BarrierSet::barrier_set()->barrier_set_assembler();
334 bs->nmethod_entry_barrier(this, nullptr /* slow_path */, nullptr /* continuation */, nullptr /* guard */);
335 }
336
337 void C1_MacroAssembler::remove_frame(int framesize) {
338 MacroAssembler::remove_frame(framesize);
339 }
340
341
342 void C1_MacroAssembler::verified_entry(bool breakAtEntry) {
343 // If we have to make this method not-entrant we'll overwrite its
344 // first instruction with a jump. For this action to be legal we
345 // must ensure that this first instruction is a J, JAL or NOP.
346 // Make it a NOP.
347 IncompressibleRegion ir(this); // keep the nop as 4 bytes for patching.
348 assert_alignment(pc());
349 nop(); // 4 bytes
350 }
351
352 void C1_MacroAssembler::load_parameter(int offset_in_words, Register reg) {
353 // fp + -2: link
354 // + -1: return address
355 // + 0: argument with offset 0
356 // + 1: argument with offset 1
357 // + 2: ...
358 ld(reg, Address(fp, offset_in_words * BytesPerWord));
359 }
360
361 #ifndef PRODUCT
362
363 void C1_MacroAssembler::verify_stack_oop(int stack_offset) {
364 if (!VerifyOops) {
365 return;
366 }
367 verify_oop_addr(Address(sp, stack_offset));
368 }
369
370 void C1_MacroAssembler::verify_not_null_oop(Register r) {
371 if (!VerifyOops) return;
372 Label not_null;
373 bnez(r, not_null);
374 stop("non-null oop required");
375 bind(not_null);
376 verify_oop(r);
377 }
378
379 void C1_MacroAssembler::invalidate_registers(bool inv_x10, bool inv_x9, bool inv_x12, bool inv_x13, bool inv_x14, bool inv_x15) {
380 #ifdef ASSERT
381 static int nn;
382 if (inv_x10) { mv(x10, 0xDEAD); }
383 if (inv_x9) { mv(x9, 0xDEAD); }
384 if (inv_x12) { mv(x12, nn++); }
385 if (inv_x13) { mv(x13, 0xDEAD); }
386 if (inv_x14) { mv(x14, 0xDEAD); }
387 if (inv_x15) { mv(x15, 0xDEAD); }
388 #endif // ASSERT
389 }
390 #endif // ifndef PRODUCT
391
392 typedef void (C1_MacroAssembler::*c1_cond_branch_insn)(Register op1, Register op2, Label& label, bool is_far);
393 typedef void (C1_MacroAssembler::*c1_float_cond_branch_insn)(FloatRegister op1, FloatRegister op2,
394 Label& label, bool is_far, bool is_unordered);
395
396 static c1_cond_branch_insn c1_cond_branch[] =
397 {
398 /* SHORT branches */
399 (c1_cond_branch_insn)&MacroAssembler::beq,
400 (c1_cond_branch_insn)&MacroAssembler::bne,
401 (c1_cond_branch_insn)&MacroAssembler::blt,
402 (c1_cond_branch_insn)&MacroAssembler::ble,
403 (c1_cond_branch_insn)&MacroAssembler::bge,
404 (c1_cond_branch_insn)&MacroAssembler::bgt,
405 (c1_cond_branch_insn)&MacroAssembler::bleu, // lir_cond_belowEqual
406 (c1_cond_branch_insn)&MacroAssembler::bgeu // lir_cond_aboveEqual
407 };
408
409 static c1_float_cond_branch_insn c1_float_cond_branch[] =
410 {
411 /* FLOAT branches */
412 (c1_float_cond_branch_insn)&MacroAssembler::float_beq,
413 (c1_float_cond_branch_insn)&MacroAssembler::float_bne,
414 (c1_float_cond_branch_insn)&MacroAssembler::float_blt,
415 (c1_float_cond_branch_insn)&MacroAssembler::float_ble,
416 (c1_float_cond_branch_insn)&MacroAssembler::float_bge,
417 (c1_float_cond_branch_insn)&MacroAssembler::float_bgt,
418 nullptr, // lir_cond_belowEqual
419 nullptr, // lir_cond_aboveEqual
420
421 /* DOUBLE branches */
422 (c1_float_cond_branch_insn)&MacroAssembler::double_beq,
423 (c1_float_cond_branch_insn)&MacroAssembler::double_bne,
424 (c1_float_cond_branch_insn)&MacroAssembler::double_blt,
425 (c1_float_cond_branch_insn)&MacroAssembler::double_ble,
426 (c1_float_cond_branch_insn)&MacroAssembler::double_bge,
427 (c1_float_cond_branch_insn)&MacroAssembler::double_bgt,
428 nullptr, // lir_cond_belowEqual
429 nullptr // lir_cond_aboveEqual
430 };
431
432 void C1_MacroAssembler::c1_cmp_branch(int cmpFlag, Register op1, Register op2, Label& label,
433 BasicType type, bool is_far) {
434 if (type == T_OBJECT || type == T_ARRAY) {
435 assert(cmpFlag == lir_cond_equal || cmpFlag == lir_cond_notEqual, "Should be equal or notEqual");
436 if (cmpFlag == lir_cond_equal) {
437 beq(op1, op2, label, is_far);
438 } else {
439 bne(op1, op2, label, is_far);
440 }
441 } else {
442 assert(cmpFlag >= 0 && cmpFlag < (int)(sizeof(c1_cond_branch) / sizeof(c1_cond_branch[0])),
443 "invalid c1 conditional branch index");
444 (this->*c1_cond_branch[cmpFlag])(op1, op2, label, is_far);
445 }
446 }
447
448 void C1_MacroAssembler::c1_float_cmp_branch(int cmpFlag, FloatRegister op1, FloatRegister op2, Label& label,
449 bool is_far, bool is_unordered) {
450 assert(cmpFlag >= 0 &&
451 cmpFlag < (int)(sizeof(c1_float_cond_branch) / sizeof(c1_float_cond_branch[0])),
452 "invalid c1 float conditional branch index");
453 (this->*c1_float_cond_branch[cmpFlag])(op1, op2, label, is_far, is_unordered);
454 }