1 /*
2 * Copyright (c) 1999, 2024, Oracle and/or its affiliates. All rights reserved.
3 * Copyright (c) 2014, 2021, Red Hat Inc. All rights reserved.
4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5 *
6 * This code is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 only, as
8 * published by the Free Software Foundation.
9 *
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
22 * questions.
23 *
24 */
25
26 #include "precompiled.hpp"
27 #include "c1/c1_MacroAssembler.hpp"
28 #include "c1/c1_Runtime1.hpp"
29 #include "gc/shared/barrierSetAssembler.hpp"
30 #include "gc/shared/collectedHeap.hpp"
31 #include "gc/shared/tlab_globals.hpp"
32 #include "interpreter/interpreter.hpp"
33 #include "oops/arrayOop.hpp"
34 #include "oops/markWord.hpp"
35 #include "runtime/basicLock.hpp"
36 #include "runtime/biasedLocking.hpp"
37 #include "runtime/os.hpp"
38 #include "runtime/sharedRuntime.hpp"
39 #include "runtime/stubRoutines.hpp"
40
41 void C1_MacroAssembler::float_cmp(bool is_float, int unordered_result,
42 FloatRegister f0, FloatRegister f1,
43 Register result)
44 {
45 Label done;
46 if (is_float) {
47 fcmps(f0, f1);
48 } else {
49 fcmpd(f0, f1);
50 }
51 if (unordered_result < 0) {
52 // we want -1 for unordered or less than, 0 for equal and 1 for
53 // greater than.
54 cset(result, NE); // Not equal or unordered
55 cneg(result, result, LT); // Less than or unordered
56 } else {
57 // we want -1 for less than, 0 for equal and 1 for unordered or
58 // greater than.
59 cset(result, NE); // Not equal or unordered
60 cneg(result, result, LO); // Less than
61 }
62 }
63
64 int C1_MacroAssembler::lock_object(Register hdr, Register obj, Register disp_hdr, Register temp, Label& slow_case) {
65 const int aligned_mask = BytesPerWord -1;
66 const int hdr_offset = oopDesc::mark_offset_in_bytes();
67 assert_different_registers(hdr, obj, disp_hdr, temp, rscratch2);
68 Label done;
69 int null_check_offset = -1;
70
71 verify_oop(obj);
72
73 // save object being locked into the BasicObjectLock
74 str(obj, Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes()));
75
76 null_check_offset = offset();
77
78 if (DiagnoseSyncOnValueBasedClasses != 0) {
79 load_klass(hdr, obj);
80 ldrw(hdr, Address(hdr, Klass::access_flags_offset()));
81 tstw(hdr, JVM_ACC_IS_VALUE_BASED_CLASS);
82 br(Assembler::NE, slow_case);
83 }
84
85 if (UseBiasedLocking) {
86 assert(temp != noreg, "should have temp register at this point");
87 biased_locking_enter(disp_hdr, obj, hdr, temp, false, done, &slow_case);
88 }
89
90 if (LockingMode == LM_LIGHTWEIGHT) {
91 lightweight_lock(obj, hdr, temp, rscratch2, slow_case);
92 } else {
93 // Load object header
94 ldr(hdr, Address(obj, hdr_offset));
95 // and mark it as unlocked
96 orr(hdr, hdr, markWord::unlocked_value);
97 // save unlocked object header into the displaced header location on the stack
98 str(hdr, Address(disp_hdr, 0));
99 // test if object header is still the same (i.e. unlocked), and if so, store the
100 // displaced header address in the object header - if it is not the same, get the
101 // object header instead
102 lea(rscratch2, Address(obj, hdr_offset));
103 cmpxchgptr(hdr, disp_hdr, rscratch2, rscratch1, done, /*fallthough*/NULL);
104 // if the object header was the same, we're done
105 // if the object header was not the same, it is now in the hdr register
106 // => test if it is a stack pointer into the same stack (recursive locking), i.e.:
107 //
108 // 1) (hdr & aligned_mask) == 0
109 // 2) sp <= hdr
110 // 3) hdr <= sp + page_size
111 //
112 // these 3 tests can be done by evaluating the following expression:
113 //
114 // (hdr - sp) & (aligned_mask - page_size)
115 //
116 // assuming both the stack pointer and page_size have their least
117 // significant 2 bits cleared and page_size is a power of 2
118 mov(rscratch1, sp);
119 sub(hdr, hdr, rscratch1);
120 ands(hdr, hdr, aligned_mask - os::vm_page_size());
121 // for recursive locking, the result is zero => save it in the displaced header
122 // location (NULL in the displaced hdr location indicates recursive locking)
123 str(hdr, Address(disp_hdr, 0));
124 // otherwise we don't care about the result and handle locking via runtime call
125 cbnz(hdr, slow_case);
126 // done
127 bind(done);
128 }
129 if (PrintBiasedLockingStatistics) {
130 lea(rscratch2, ExternalAddress((address)BiasedLocking::fast_path_entry_count_addr()));
131 addmw(Address(rscratch2, 0), 1, rscratch1);
132 }
133 return null_check_offset;
134 }
135
136
137 void C1_MacroAssembler::unlock_object(Register hdr, Register obj, Register disp_hdr, Register temp, Label& slow_case) {
138 const int aligned_mask = BytesPerWord -1;
139 const int hdr_offset = oopDesc::mark_offset_in_bytes();
140 assert_different_registers(hdr, obj, disp_hdr, temp, rscratch2);
141 Label done;
142
143 if (UseBiasedLocking) {
144 // load object
145 ldr(obj, Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes()));
146 biased_locking_exit(obj, hdr, done);
147 }
148
149 if (LockingMode != LM_LIGHTWEIGHT) {
150 // load displaced header
151 ldr(hdr, Address(disp_hdr, 0));
152 // if the loaded hdr is null we had recursive locking
153 // if we had recursive locking, we are done
154 cbz(hdr, done);
155 }
156
157 if (!UseBiasedLocking) {
158 // load object
159 ldr(obj, Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes()));
160 }
161 verify_oop(obj);
162
163 if (LockingMode == LM_LIGHTWEIGHT) {
164 lightweight_unlock(obj, hdr, temp, rscratch2, slow_case);
165 } else {
166 // test if object header is pointing to the displaced header, and if so, restore
167 // the displaced header in the object - if the object header is not pointing to
168 // the displaced header, get the object header instead
169 // if the object header was not pointing to the displaced header,
170 // we do unlocking via runtime call
171 if (hdr_offset) {
172 lea(rscratch1, Address(obj, hdr_offset));
173 cmpxchgptr(disp_hdr, hdr, rscratch1, rscratch2, done, &slow_case);
174 } else {
175 cmpxchgptr(disp_hdr, hdr, obj, rscratch2, done, &slow_case);
176 }
177 // done
178 bind(done);
179 }
180 }
181
182
183 // Defines obj, preserves var_size_in_bytes
184 void C1_MacroAssembler::try_allocate(Register obj, Register var_size_in_bytes, int con_size_in_bytes, Register t1, Register t2, Label& slow_case) {
185 if (UseTLAB) {
186 tlab_allocate(obj, var_size_in_bytes, con_size_in_bytes, t1, t2, slow_case);
187 } else {
188 eden_allocate(obj, var_size_in_bytes, con_size_in_bytes, t1, slow_case);
189 }
190 }
191
192 void C1_MacroAssembler::initialize_header(Register obj, Register klass, Register len, Register t1, Register t2) {
193 assert_different_registers(obj, klass, len);
194 if (UseCompactObjectHeaders || (UseBiasedLocking && !len->is_valid())) {
195 assert_different_registers(obj, klass, len, t1, t2);
196 ldr(t1, Address(klass, Klass::prototype_header_offset()));
197 } else {
198 // This assumes that all prototype bits fit in an int32_t
199 mov(t1, (int32_t)(intptr_t)markWord::prototype().value());
200 }
201 str(t1, Address(obj, oopDesc::mark_offset_in_bytes()));
202
203 if (!UseCompactObjectHeaders) {
204 if (UseCompressedClassPointers) { // Take care not to kill klass
205 encode_klass_not_null(t1, klass);
206 strw(t1, Address(obj, oopDesc::klass_offset_in_bytes()));
207 } else {
208 str(klass, Address(obj, oopDesc::klass_offset_in_bytes()));
209 }
210 }
211
212 if (len->is_valid()) {
213 strw(len, Address(obj, arrayOopDesc::length_offset_in_bytes()));
214 } else if (UseCompressedClassPointers && !UseCompactObjectHeaders) {
215 store_klass_gap(obj, zr);
216 }
217 }
218
219 // preserves obj, destroys len_in_bytes
220 //
221 // Scratch registers: t1 = r10, t2 = r11
222 //
223 void C1_MacroAssembler::initialize_body(Register obj, Register len_in_bytes, int hdr_size_in_bytes, Register t1, Register t2) {
224 assert(hdr_size_in_bytes >= 0, "header size must be positive or 0");
225 assert(t1 == r10 && t2 == r11, "must be");
226
227 Label done;
228
229 // len_in_bytes is positive and ptr sized
230 subs(len_in_bytes, len_in_bytes, hdr_size_in_bytes);
231 br(Assembler::EQ, done);
232
233 // Zero first 4 bytes, if start offset is not word aligned.
234 if (!is_aligned(hdr_size_in_bytes, BytesPerWord)) {
235 strw(zr, Address(obj, hdr_size_in_bytes));
236 hdr_size_in_bytes += BytesPerInt;
237 }
238
239 // zero_words() takes ptr in r10 and count in words in r11
240 mov(rscratch1, len_in_bytes);
241 lea(t1, Address(obj, hdr_size_in_bytes));
242 lsr(t2, rscratch1, LogBytesPerWord);
243 zero_words(t1, t2);
244
245 bind(done);
246 }
247
248
249 void C1_MacroAssembler::allocate_object(Register obj, Register t1, Register t2, int header_size, int object_size, Register klass, Label& slow_case) {
250 assert_different_registers(obj, t1, t2); // XXX really?
251 assert(header_size >= 0 && object_size >= header_size, "illegal sizes");
252
253 try_allocate(obj, noreg, object_size * BytesPerWord, t1, t2, slow_case);
254
255 initialize_object(obj, klass, noreg, object_size * HeapWordSize, t1, t2, UseTLAB);
256 }
257
258 // Scratch registers: t1 = r10, t2 = r11
259 void C1_MacroAssembler::initialize_object(Register obj, Register klass, Register var_size_in_bytes, int con_size_in_bytes, Register t1, Register t2, bool is_tlab_allocated) {
260 assert((con_size_in_bytes & MinObjAlignmentInBytesMask) == 0,
261 "con_size_in_bytes is not multiple of alignment");
262 const int hdr_size_in_bytes = instanceOopDesc::header_size() * HeapWordSize;
263
264 initialize_header(obj, klass, noreg, t1, t2);
265
266 if (!(UseTLAB && ZeroTLAB && is_tlab_allocated)) {
267 // clear rest of allocated space
268 const Register index = t2;
269 if (var_size_in_bytes != noreg) {
270 mov(index, var_size_in_bytes);
271 initialize_body(obj, index, hdr_size_in_bytes, t1, t2);
272 } else if (con_size_in_bytes > hdr_size_in_bytes) {
273 con_size_in_bytes -= hdr_size_in_bytes;
274 lea(t1, Address(obj, hdr_size_in_bytes));
275 zero_words(t1, con_size_in_bytes / BytesPerWord);
276 }
277 }
278
279 membar(StoreStore);
280
281 if (CURRENT_ENV->dtrace_alloc_probes()) {
282 assert(obj == r0, "must be");
283 far_call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id)));
284 }
285
286 verify_oop(obj);
287 }
288 void C1_MacroAssembler::allocate_array(Register obj, Register len, Register t1, Register t2, int base_offset_in_bytes, int f, Register klass, Label& slow_case) {
289 assert_different_registers(obj, len, t1, t2, klass);
290
291 // determine alignment mask
292 assert(!(BytesPerWord & 1), "must be a multiple of 2 for masking code to work");
293
294 // check for negative or excessive length
295 mov(rscratch1, (int32_t)max_array_allocation_length);
296 cmp(len, rscratch1);
297 br(Assembler::HS, slow_case);
298
299 const Register arr_size = t2; // okay to be the same
300 // align object end
301 mov(arr_size, (int32_t)base_offset_in_bytes + MinObjAlignmentInBytesMask);
302 add(arr_size, arr_size, len, ext::uxtw, f);
303 andr(arr_size, arr_size, ~MinObjAlignmentInBytesMask);
304
305 try_allocate(obj, arr_size, 0, t1, t2, slow_case);
306
307 initialize_header(obj, klass, len, t1, t2);
308
309 // clear rest of allocated space
310 initialize_body(obj, arr_size, base_offset_in_bytes, t1, t2);
311
312 membar(StoreStore);
313
314 if (CURRENT_ENV->dtrace_alloc_probes()) {
315 assert(obj == r0, "must be");
316 far_call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id)));
317 }
318
319 verify_oop(obj);
320 }
321
322
323 void C1_MacroAssembler::inline_cache_check(Register receiver, Register iCache) {
324 verify_oop(receiver);
325 // explicit NULL check not needed since load from [klass_offset] causes a trap
326 // check against inline cache
327 if (UseCompactObjectHeaders) {
328 assert(!MacroAssembler::needs_explicit_null_check(oopDesc::mark_offset_in_bytes()), "must add explicit null check");
329 } else {
330 assert(!MacroAssembler::needs_explicit_null_check(oopDesc::klass_offset_in_bytes()), "must add explicit null check");
331 }
332 cmp_klass(receiver, iCache, rscratch1);
333 }
334
335
336 void C1_MacroAssembler::build_frame(int framesize, int bang_size_in_bytes) {
337 assert(bang_size_in_bytes >= framesize, "stack bang size incorrect");
338 // Make sure there is enough stack space for this method's activation.
339 // Note that we do this before creating a frame.
340 generate_stack_overflow_check(bang_size_in_bytes);
341 MacroAssembler::build_frame(framesize);
342
343 // Insert nmethod entry barrier into frame.
344 BarrierSetAssembler* bs = BarrierSet::barrier_set()->barrier_set_assembler();
345 bs->nmethod_entry_barrier(this);
346 }
347
348 void C1_MacroAssembler::remove_frame(int framesize) {
349 MacroAssembler::remove_frame(framesize);
350 }
351
352
353 void C1_MacroAssembler::verified_entry(bool breakAtEntry) {
354 // If we have to make this method not-entrant we'll overwrite its
355 // first instruction with a jump. For this action to be legal we
356 // must ensure that this first instruction is a B, BL, NOP, BKPT,
357 // SVC, HVC, or SMC. Make it a NOP.
358 nop();
359 }
360
361 void C1_MacroAssembler::load_parameter(int offset_in_words, Register reg) {
362 // rbp, + 0: link
363 // + 1: return address
364 // + 2: argument with offset 0
365 // + 3: argument with offset 1
366 // + 4: ...
367
368 ldr(reg, Address(rfp, (offset_in_words + 2) * BytesPerWord));
369 }
370
371 #ifndef PRODUCT
372
373 void C1_MacroAssembler::verify_stack_oop(int stack_offset) {
374 if (!VerifyOops) return;
375 verify_oop_addr(Address(sp, stack_offset), "oop");
376 }
377
378 void C1_MacroAssembler::verify_not_null_oop(Register r) {
379 if (!VerifyOops) return;
380 Label not_null;
381 cbnz(r, not_null);
382 stop("non-null oop required");
383 bind(not_null);
384 verify_oop(r);
385 }
386
387 void C1_MacroAssembler::invalidate_registers(bool inv_r0, bool inv_r19, bool inv_r2, bool inv_r3, bool inv_r4, bool inv_r5) {
388 #ifdef ASSERT
389 static int nn;
390 if (inv_r0) mov(r0, 0xDEAD);
391 if (inv_r19) mov(r19, 0xDEAD);
392 if (inv_r2) mov(r2, nn++);
393 if (inv_r3) mov(r3, 0xDEAD);
394 if (inv_r4) mov(r4, 0xDEAD);
395 if (inv_r5) mov(r5, 0xDEAD);
396 #endif
397 }
398 #endif // ifndef PRODUCT