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 lbu(hdr, Address(hdr, Klass::misc_flags_offset()));
68 test_bit(temp, hdr, exact_log2(KlassFlags::_misc_is_value_based_class));
69 bnez(temp, slow_case, true /* is_far */);
70 }
71
72 if (LockingMode == LM_LIGHTWEIGHT) {
73 lightweight_lock(disp_hdr, 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 // if the object header was the same, we're done
87 cmpxchgptr(hdr, disp_hdr, temp, t1, done, /*fallthough*/nullptr);
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
110 // done
111 bind(done);
112 inc_held_monitor_count();
113 }
114
115 return null_check_offset;
116 }
117
118 void C1_MacroAssembler::unlock_object(Register hdr, Register obj, Register disp_hdr, Register temp, Label& slow_case) {
119 const int aligned_mask = BytesPerWord - 1;
120 const int hdr_offset = oopDesc::mark_offset_in_bytes();
121 assert_different_registers(hdr, obj, disp_hdr, temp, t0, t1);
122 Label done;
123
124 if (LockingMode != LM_LIGHTWEIGHT) {
125 // load displaced header
126 ld(hdr, Address(disp_hdr, 0));
127 // if the loaded hdr is null we had recursive locking
128 // if we had recursive locking, we are done
129 beqz(hdr, done);
130 }
131
132 // load object
133 ld(obj, Address(disp_hdr, BasicObjectLock::obj_offset()));
134 verify_oop(obj);
135
136 if (LockingMode == LM_LIGHTWEIGHT) {
137 lightweight_unlock(obj, hdr, temp, t1, slow_case);
138 } else if (LockingMode == LM_LEGACY) {
139 // test if object header is pointing to the displaced header, and if so, restore
140 // the displaced header in the object - if the object header is not pointing to
141 // the displaced header, get the object header instead
142 // if the object header was not pointing to the displaced header,
143 // we do unlocking via runtime call
144 if (hdr_offset) {
145 la(temp, Address(obj, hdr_offset));
146 cmpxchgptr(disp_hdr, hdr, temp, t1, done, &slow_case);
147 } else {
148 cmpxchgptr(disp_hdr, hdr, obj, t1, done, &slow_case);
149 }
150
151 // done
152 bind(done);
153 dec_held_monitor_count();
154 }
155 }
156
157 // Defines obj, preserves var_size_in_bytes
158 void C1_MacroAssembler::try_allocate(Register obj, Register var_size_in_bytes, int con_size_in_bytes, Register tmp1, Register tmp2, Label& slow_case) {
159 if (UseTLAB) {
160 tlab_allocate(obj, var_size_in_bytes, con_size_in_bytes, tmp1, tmp2, slow_case, /* is_far */ true);
161 } else {
162 j(slow_case);
163 }
164 }
165
166 void C1_MacroAssembler::initialize_header(Register obj, Register klass, Register len, Register tmp1, Register tmp2) {
167 assert_different_registers(obj, klass, len, tmp1, tmp2);
168 // This assumes that all prototype bits fitr in an int32_t
169 mv(tmp1, (int32_t)(intptr_t)markWord::prototype().value());
170 sd(tmp1, Address(obj, oopDesc::mark_offset_in_bytes()));
171
172 if (UseCompressedClassPointers) { // Take care not to kill klass
173 encode_klass_not_null(tmp1, klass, tmp2);
174 sw(tmp1, Address(obj, oopDesc::klass_offset_in_bytes()));
175 } else {
176 sd(klass, Address(obj, oopDesc::klass_offset_in_bytes()));
177 }
178
179 if (len->is_valid()) {
180 sw(len, Address(obj, arrayOopDesc::length_offset_in_bytes()));
181 int base_offset = arrayOopDesc::length_offset_in_bytes() + BytesPerInt;
182 if (!is_aligned(base_offset, BytesPerWord)) {
183 assert(is_aligned(base_offset, BytesPerInt), "must be 4-byte aligned");
184 // Clear gap/first 4 bytes following the length field.
185 sw(zr, Address(obj, base_offset));
186 }
187 } else if (UseCompressedClassPointers) {
188 store_klass_gap(obj, zr);
189 }
190 }
191
192 // preserves obj, destroys len_in_bytes
193 void C1_MacroAssembler::initialize_body(Register obj, Register len_in_bytes, int hdr_size_in_bytes, Register tmp) {
194 assert(hdr_size_in_bytes >= 0, "header size must be positive or 0");
195 Label done;
196
197 // len_in_bytes is positive and ptr sized
198 sub(len_in_bytes, len_in_bytes, hdr_size_in_bytes);
199 beqz(len_in_bytes, done);
200
201 // Preserve obj
202 if (hdr_size_in_bytes) {
203 add(obj, obj, hdr_size_in_bytes);
204 }
205 zero_memory(obj, len_in_bytes, tmp);
206 if (hdr_size_in_bytes) {
207 sub(obj, obj, hdr_size_in_bytes);
208 }
209
210 bind(done);
211 }
212
213 void C1_MacroAssembler::allocate_object(Register obj, Register tmp1, Register tmp2, int header_size, int object_size, Register klass, Label& slow_case) {
214 assert_different_registers(obj, tmp1, tmp2);
215 assert(header_size >= 0 && object_size >= header_size, "illegal sizes");
216
217 try_allocate(obj, noreg, object_size * BytesPerWord, tmp1, tmp2, slow_case);
218
219 initialize_object(obj, klass, noreg, object_size * HeapWordSize, tmp1, tmp2, UseTLAB);
220 }
221
222 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) {
223 assert((con_size_in_bytes & MinObjAlignmentInBytesMask) == 0,
224 "con_size_in_bytes is not multiple of alignment");
225 const int hdr_size_in_bytes = instanceOopDesc::header_size() * HeapWordSize;
226
227 initialize_header(obj, klass, noreg, tmp1, tmp2);
228
229 if (!(UseTLAB && ZeroTLAB && is_tlab_allocated)) {
230 // clear rest of allocated space
231 const Register index = tmp2;
232 // 16: multiplier for threshold
233 const int threshold = 16 * BytesPerWord; // approximate break even point for code size (see comments below)
234 if (var_size_in_bytes != noreg) {
235 mv(index, var_size_in_bytes);
236 initialize_body(obj, index, hdr_size_in_bytes, tmp1);
237 } else if (con_size_in_bytes <= threshold) {
238 // use explicit null stores
239 int i = hdr_size_in_bytes;
240 if (i < con_size_in_bytes && (con_size_in_bytes % (2 * BytesPerWord))) { // 2: multiplier for BytesPerWord
241 sd(zr, Address(obj, i));
242 i += BytesPerWord;
243 }
244 for (; i < con_size_in_bytes; i += BytesPerWord) {
245 sd(zr, Address(obj, i));
246 }
247 } else if (con_size_in_bytes > hdr_size_in_bytes) {
248 block_comment("zero memory");
249 // use loop to null out the fields
250 int words = (con_size_in_bytes - hdr_size_in_bytes) / BytesPerWord;
251 mv(index, words / 8); // 8: byte size
252
253 const int unroll = 8; // Number of sd(zr) instructions we'll unroll
254 int remainder = words % unroll;
255 la(t0, Address(obj, hdr_size_in_bytes + remainder * BytesPerWord));
256
257 Label entry_point, loop;
258 j(entry_point);
259
260 bind(loop);
261 sub(index, index, 1);
262 for (int i = -unroll; i < 0; i++) {
263 if (-i == remainder) {
264 bind(entry_point);
265 }
266 sd(zr, Address(t0, i * wordSize));
267 }
268 if (remainder == 0) {
269 bind(entry_point);
270 }
271 add(t0, t0, unroll * wordSize);
272 bnez(index, loop);
273 }
274 }
275
276 membar(MacroAssembler::StoreStore);
277
278 if (CURRENT_ENV->dtrace_alloc_probes()) {
279 assert(obj == x10, "must be");
280 far_call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id)));
281 }
282
283 verify_oop(obj);
284 }
285
286 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) {
287 assert_different_registers(obj, len, tmp1, tmp2, klass);
288
289 // determine alignment mask
290 assert(!(BytesPerWord & 1), "must be multiple of 2 for masking code to work");
291
292 // check for negative or excessive length
293 mv(t0, (int32_t)max_array_allocation_length);
294 bgeu(len, t0, slow_case, /* is_far */ true);
295
296 const Register arr_size = tmp2; // okay to be the same
297 // align object end
298 mv(arr_size, (int32_t)base_offset_in_bytes + MinObjAlignmentInBytesMask);
299 shadd(arr_size, len, arr_size, t0, f);
300 andi(arr_size, arr_size, ~(uint)MinObjAlignmentInBytesMask);
301
302 try_allocate(obj, arr_size, 0, tmp1, tmp2, slow_case);
303
304 initialize_header(obj, klass, len, tmp1, tmp2);
305
306 // Align-up to word boundary, because we clear the 4 bytes potentially
307 // following the length field in initialize_header().
308 int base_offset = align_up(base_offset_in_bytes, BytesPerWord);
309
310 // clear rest of allocated space
311 const Register len_zero = len;
312 if (zero_array) {
313 initialize_body(obj, arr_size, base_offset, len_zero);
314 }
315
316 membar(MacroAssembler::StoreStore);
317
318 if (CURRENT_ENV->dtrace_alloc_probes()) {
319 assert(obj == x10, "must be");
320 far_call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id)));
321 }
322
323 verify_oop(obj);
324 }
325
326 void C1_MacroAssembler::build_frame(int framesize, int bang_size_in_bytes) {
327 assert(bang_size_in_bytes >= framesize, "stack bang size incorrect");
328 // Make sure there is enough stack space for this method's activation.
329 // Note that we do this before creating a frame.
330 generate_stack_overflow_check(bang_size_in_bytes);
331 MacroAssembler::build_frame(framesize);
332
333 // Insert nmethod entry barrier into frame.
334 BarrierSetAssembler* bs = BarrierSet::barrier_set()->barrier_set_assembler();
335 bs->nmethod_entry_barrier(this, nullptr /* slow_path */, nullptr /* continuation */, nullptr /* guard */);
336 }
337
338 void C1_MacroAssembler::remove_frame(int framesize) {
339 MacroAssembler::remove_frame(framesize);
340 }
341
342
343 void C1_MacroAssembler::verified_entry(bool breakAtEntry) {
344 // If we have to make this method not-entrant we'll overwrite its
345 // first instruction with a jump. For this action to be legal we
346 // must ensure that this first instruction is a J, JAL or NOP.
347 // Make it a NOP.
348 IncompressibleRegion ir(this); // keep the nop as 4 bytes for patching.
349 assert_alignment(pc());
350 nop(); // 4 bytes
351 }
352
353 void C1_MacroAssembler::load_parameter(int offset_in_words, Register reg) {
354 // fp + -2: link
355 // + -1: return address
356 // + 0: argument with offset 0
357 // + 1: argument with offset 1
358 // + 2: ...
359 ld(reg, Address(fp, offset_in_words * BytesPerWord));
360 }
361
362 #ifndef PRODUCT
363
364 void C1_MacroAssembler::verify_stack_oop(int stack_offset) {
365 if (!VerifyOops) {
366 return;
367 }
368 verify_oop_addr(Address(sp, stack_offset));
369 }
370
371 void C1_MacroAssembler::verify_not_null_oop(Register r) {
372 if (!VerifyOops) return;
373 Label not_null;
374 bnez(r, not_null);
375 stop("non-null oop required");
376 bind(not_null);
377 verify_oop(r);
378 }
379
380 void C1_MacroAssembler::invalidate_registers(bool inv_x10, bool inv_x9, bool inv_x12, bool inv_x13, bool inv_x14, bool inv_x15) {
381 #ifdef ASSERT
382 static int nn;
383 if (inv_x10) { mv(x10, 0xDEAD); }
384 if (inv_x9) { mv(x9, 0xDEAD); }
385 if (inv_x12) { mv(x12, nn++); }
386 if (inv_x13) { mv(x13, 0xDEAD); }
387 if (inv_x14) { mv(x14, 0xDEAD); }
388 if (inv_x15) { mv(x15, 0xDEAD); }
389 #endif // ASSERT
390 }
391 #endif // ifndef PRODUCT
392
393 typedef void (C1_MacroAssembler::*c1_cond_branch_insn)(Register op1, Register op2, Label& label, bool is_far);
394 typedef void (C1_MacroAssembler::*c1_float_cond_branch_insn)(FloatRegister op1, FloatRegister op2,
395 Label& label, bool is_far, bool is_unordered);
396
397 static c1_cond_branch_insn c1_cond_branch[] =
398 {
399 /* SHORT branches */
400 (c1_cond_branch_insn)&MacroAssembler::beq,
401 (c1_cond_branch_insn)&MacroAssembler::bne,
402 (c1_cond_branch_insn)&MacroAssembler::blt,
403 (c1_cond_branch_insn)&MacroAssembler::ble,
404 (c1_cond_branch_insn)&MacroAssembler::bge,
405 (c1_cond_branch_insn)&MacroAssembler::bgt,
406 (c1_cond_branch_insn)&MacroAssembler::bleu, // lir_cond_belowEqual
407 (c1_cond_branch_insn)&MacroAssembler::bgeu // lir_cond_aboveEqual
408 };
409
410 static c1_float_cond_branch_insn c1_float_cond_branch[] =
411 {
412 /* FLOAT branches */
413 (c1_float_cond_branch_insn)&MacroAssembler::float_beq,
414 (c1_float_cond_branch_insn)&MacroAssembler::float_bne,
415 (c1_float_cond_branch_insn)&MacroAssembler::float_blt,
416 (c1_float_cond_branch_insn)&MacroAssembler::float_ble,
417 (c1_float_cond_branch_insn)&MacroAssembler::float_bge,
418 (c1_float_cond_branch_insn)&MacroAssembler::float_bgt,
419 nullptr, // lir_cond_belowEqual
420 nullptr, // lir_cond_aboveEqual
421
422 /* DOUBLE branches */
423 (c1_float_cond_branch_insn)&MacroAssembler::double_beq,
424 (c1_float_cond_branch_insn)&MacroAssembler::double_bne,
425 (c1_float_cond_branch_insn)&MacroAssembler::double_blt,
426 (c1_float_cond_branch_insn)&MacroAssembler::double_ble,
427 (c1_float_cond_branch_insn)&MacroAssembler::double_bge,
428 (c1_float_cond_branch_insn)&MacroAssembler::double_bgt,
429 nullptr, // lir_cond_belowEqual
430 nullptr // lir_cond_aboveEqual
431 };
432
433 void C1_MacroAssembler::c1_cmp_branch(int cmpFlag, Register op1, Register op2, Label& label,
434 BasicType type, bool is_far) {
435 if (type == T_OBJECT || type == T_ARRAY) {
436 assert(cmpFlag == lir_cond_equal || cmpFlag == lir_cond_notEqual, "Should be equal or notEqual");
437 if (cmpFlag == lir_cond_equal) {
438 beq(op1, op2, label, is_far);
439 } else {
440 bne(op1, op2, label, is_far);
441 }
442 } else {
443 assert(cmpFlag >= 0 && cmpFlag < (int)(sizeof(c1_cond_branch) / sizeof(c1_cond_branch[0])),
444 "invalid c1 conditional branch index");
445 (this->*c1_cond_branch[cmpFlag])(op1, op2, label, is_far);
446 }
447 }
448
449 void C1_MacroAssembler::c1_float_cmp_branch(int cmpFlag, FloatRegister op1, FloatRegister op2, Label& label,
450 bool is_far, bool is_unordered) {
451 assert(cmpFlag >= 0 &&
452 cmpFlag < (int)(sizeof(c1_float_cond_branch) / sizeof(c1_float_cond_branch[0])),
453 "invalid c1 float conditional branch index");
454 (this->*c1_float_cond_branch[cmpFlag])(op1, op2, label, is_far, is_unordered);
455 }