1 /*
2 * Copyright (c) 1999, 2025, 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 "c1/c1_MacroAssembler.hpp"
27 #include "c1/c1_Runtime1.hpp"
28 #include "gc/shared/barrierSetAssembler.hpp"
29 #include "gc/shared/collectedHeap.hpp"
30 #include "gc/shared/tlab_globals.hpp"
31 #include "interpreter/interpreter.hpp"
32 #include "oops/arrayOop.hpp"
33 #include "oops/markWord.hpp"
34 #include "runtime/basicLock.hpp"
35 #include "runtime/os.hpp"
36 #include "runtime/sharedRuntime.hpp"
37 #include "runtime/stubRoutines.hpp"
38
39 void C1_MacroAssembler::float_cmp(bool is_float, int unordered_result,
40 FloatRegister f0, FloatRegister f1,
41 Register result)
42 {
43 Label done;
44 if (is_float) {
45 fcmps(f0, f1);
46 } else {
47 fcmpd(f0, f1);
48 }
49 if (unordered_result < 0) {
50 // we want -1 for unordered or less than, 0 for equal and 1 for
51 // greater than.
52 cset(result, NE); // Not equal or unordered
53 cneg(result, result, LT); // Less than or unordered
54 } else {
55 // we want -1 for less than, 0 for equal and 1 for unordered or
56 // greater than.
57 cset(result, NE); // Not equal or unordered
58 cneg(result, result, LO); // Less than
59 }
60 }
61
62 int C1_MacroAssembler::lock_object(Register hdr, Register obj, Register disp_hdr, Register temp, Label& slow_case) {
63 const int aligned_mask = BytesPerWord -1;
64 const int hdr_offset = oopDesc::mark_offset_in_bytes();
65 assert_different_registers(hdr, obj, disp_hdr, temp, rscratch2);
66 int null_check_offset = -1;
67
68 verify_oop(obj);
69
70 // save object being locked into the BasicObjectLock
71 str(obj, Address(disp_hdr, BasicObjectLock::obj_offset()));
72
73 null_check_offset = offset();
74
75 if (DiagnoseSyncOnValueBasedClasses != 0) {
76 load_klass(hdr, obj);
77 ldrb(hdr, Address(hdr, Klass::misc_flags_offset()));
78 tst(hdr, KlassFlags::_misc_is_value_based_class);
79 br(Assembler::NE, slow_case);
80 }
81
82 if (LockingMode == LM_LIGHTWEIGHT) {
83 lightweight_lock(disp_hdr, obj, hdr, temp, rscratch2, slow_case);
84 } else if (LockingMode == LM_LEGACY) {
85 Label done;
86 // Load object header
87 ldr(hdr, Address(obj, hdr_offset));
88 // and mark it as unlocked
89 orr(hdr, hdr, markWord::unlocked_value);
90 // save unlocked object header into the displaced header location on the stack
91 str(hdr, Address(disp_hdr, 0));
92 // test if object header is still the same (i.e. unlocked), and if so, store the
93 // displaced header address in the object header - if it is not the same, get the
94 // object header instead
95 lea(rscratch2, Address(obj, hdr_offset));
96 cmpxchgptr(hdr, disp_hdr, rscratch2, rscratch1, done, /*fallthough*/nullptr);
97 // if the object header was the same, we're done
98 // if the object header was not the same, it is now in the hdr register
99 // => test if it is a stack pointer into the same stack (recursive locking), i.e.:
100 //
101 // 1) (hdr & aligned_mask) == 0
102 // 2) sp <= hdr
103 // 3) hdr <= sp + page_size
104 //
105 // these 3 tests can be done by evaluating the following expression:
106 //
107 // (hdr - sp) & (aligned_mask - page_size)
108 //
109 // assuming both the stack pointer and page_size have their least
110 // significant 2 bits cleared and page_size is a power of 2
111 mov(rscratch1, sp);
112 sub(hdr, hdr, rscratch1);
113 ands(hdr, hdr, aligned_mask - (int)os::vm_page_size());
114 // for recursive locking, the result is zero => save it in the displaced header
115 // location (null in the displaced hdr location indicates recursive locking)
116 str(hdr, Address(disp_hdr, 0));
117 // otherwise we don't care about the result and handle locking via runtime call
118 cbnz(hdr, slow_case);
119 // done
120 bind(done);
121 inc_held_monitor_count(rscratch1);
122 }
123 return null_check_offset;
124 }
125
126
127 void C1_MacroAssembler::unlock_object(Register hdr, Register obj, Register disp_hdr, Register temp, Label& slow_case) {
128 const int aligned_mask = BytesPerWord -1;
129 const int hdr_offset = oopDesc::mark_offset_in_bytes();
130 assert_different_registers(hdr, obj, disp_hdr, temp, rscratch2);
131 Label done;
132
133 if (LockingMode != LM_LIGHTWEIGHT) {
134 // load displaced header
135 ldr(hdr, Address(disp_hdr, 0));
136 // if the loaded hdr is null we had recursive locking
137 // if we had recursive locking, we are done
138 cbz(hdr, done);
139 }
140
141 // load object
142 ldr(obj, Address(disp_hdr, BasicObjectLock::obj_offset()));
143 verify_oop(obj);
144
145 if (LockingMode == LM_LIGHTWEIGHT) {
146 lightweight_unlock(obj, hdr, temp, rscratch2, slow_case);
147 } else if (LockingMode == LM_LEGACY) {
148 // test if object header is pointing to the displaced header, and if so, restore
149 // the displaced header in the object - if the object header is not pointing to
150 // the displaced header, get the object header instead
151 // if the object header was not pointing to the displaced header,
152 // we do unlocking via runtime call
153 if (hdr_offset) {
154 lea(rscratch1, Address(obj, hdr_offset));
155 cmpxchgptr(disp_hdr, hdr, rscratch1, rscratch2, done, &slow_case);
156 } else {
157 cmpxchgptr(disp_hdr, hdr, obj, rscratch2, done, &slow_case);
158 }
159 // done
160 bind(done);
161 dec_held_monitor_count(rscratch1);
162 }
163 }
164
165
166 // Defines obj, preserves var_size_in_bytes
167 void C1_MacroAssembler::try_allocate(Register obj, Register var_size_in_bytes, int con_size_in_bytes, Register t1, Register t2, Label& slow_case) {
168 if (UseTLAB) {
169 tlab_allocate(obj, var_size_in_bytes, con_size_in_bytes, t1, t2, slow_case);
170 } else {
171 b(slow_case);
172 }
173 }
174
175 void C1_MacroAssembler::initialize_header(Register obj, Register klass, Register len, Register t1, Register t2) {
176 assert_different_registers(obj, klass, len);
177
178 if (UseCompactObjectHeaders) {
179 ldr(t1, Address(klass, Klass::prototype_header_offset()));
180 str(t1, Address(obj, oopDesc::mark_offset_in_bytes()));
181 } else {
182 mov(t1, checked_cast<int32_t>(markWord::prototype().value()));
183 str(t1, Address(obj, oopDesc::mark_offset_in_bytes()));
184 if (UseCompressedClassPointers) { // Take care not to kill klass
185 encode_klass_not_null(t1, klass);
186 strw(t1, Address(obj, oopDesc::klass_offset_in_bytes()));
187 } else {
188 str(klass, Address(obj, oopDesc::klass_offset_in_bytes()));
189 }
190 }
191
192 if (len->is_valid()) {
193 strw(len, Address(obj, arrayOopDesc::length_offset_in_bytes()));
194 int base_offset = arrayOopDesc::length_offset_in_bytes() + BytesPerInt;
195 if (!is_aligned(base_offset, BytesPerWord)) {
196 assert(is_aligned(base_offset, BytesPerInt), "must be 4-byte aligned");
197 // Clear gap/first 4 bytes following the length field.
198 strw(zr, Address(obj, base_offset));
199 }
200 } else if (UseCompressedClassPointers && !UseCompactObjectHeaders) {
201 store_klass_gap(obj, zr);
202 }
203 }
204
205 // preserves obj, destroys len_in_bytes
206 //
207 // Scratch registers: t1 = r10, t2 = r11
208 //
209 void C1_MacroAssembler::initialize_body(Register obj, Register len_in_bytes, int hdr_size_in_bytes, Register t1, Register t2) {
210 assert(hdr_size_in_bytes >= 0, "header size must be positive or 0");
211 assert(t1 == r10 && t2 == r11, "must be");
212
213 Label done;
214
215 // len_in_bytes is positive and ptr sized
216 subs(len_in_bytes, len_in_bytes, hdr_size_in_bytes);
217 br(Assembler::EQ, done);
218
219 // zero_words() takes ptr in r10 and count in words in r11
220 mov(rscratch1, len_in_bytes);
221 lea(t1, Address(obj, hdr_size_in_bytes));
222 lsr(t2, rscratch1, LogBytesPerWord);
223 address tpc = zero_words(t1, t2);
224
225 bind(done);
226 if (tpc == nullptr) {
227 Compilation::current()->bailout("no space for trampoline stub");
228 }
229 }
230
231
232 void C1_MacroAssembler::allocate_object(Register obj, Register t1, Register t2, int header_size, int object_size, Register klass, Label& slow_case) {
233 assert_different_registers(obj, t1, t2); // XXX really?
234 assert(header_size >= 0 && object_size >= header_size, "illegal sizes");
235
236 try_allocate(obj, noreg, object_size * BytesPerWord, t1, t2, slow_case);
237
238 initialize_object(obj, klass, noreg, object_size * HeapWordSize, t1, t2, UseTLAB);
239 }
240
241 // Scratch registers: t1 = r10, t2 = r11
242 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) {
243 assert((con_size_in_bytes & MinObjAlignmentInBytesMask) == 0,
244 "con_size_in_bytes is not multiple of alignment");
245 const int hdr_size_in_bytes = instanceOopDesc::header_size() * HeapWordSize;
246
247 initialize_header(obj, klass, noreg, t1, t2);
248
249 if (!(UseTLAB && ZeroTLAB && is_tlab_allocated)) {
250 // clear rest of allocated space
251 const Register index = t2;
252 if (var_size_in_bytes != noreg) {
253 mov(index, var_size_in_bytes);
254 initialize_body(obj, index, hdr_size_in_bytes, t1, t2);
255 if (Compilation::current()->bailed_out()) {
256 return;
257 }
258 } else if (con_size_in_bytes > hdr_size_in_bytes) {
259 con_size_in_bytes -= hdr_size_in_bytes;
260 lea(t1, Address(obj, hdr_size_in_bytes));
261 address tpc = zero_words(t1, con_size_in_bytes / BytesPerWord);
262 if (tpc == nullptr) {
263 Compilation::current()->bailout("no space for trampoline stub");
264 return;
265 }
266 }
267 }
268
269 membar(StoreStore);
270
271 if (CURRENT_ENV->dtrace_alloc_probes()) {
272 assert(obj == r0, "must be");
273 far_call(RuntimeAddress(Runtime1::entry_for(C1StubId::dtrace_object_alloc_id)));
274 }
275
276 verify_oop(obj);
277 }
278 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, bool zero_array) {
279 assert_different_registers(obj, len, t1, t2, klass);
280
281 // determine alignment mask
282 assert(!(BytesPerWord & 1), "must be a multiple of 2 for masking code to work");
283
284 // check for negative or excessive length
285 mov(rscratch1, (int32_t)max_array_allocation_length);
286 cmp(len, rscratch1);
287 br(Assembler::HS, slow_case);
288
289 const Register arr_size = t2; // okay to be the same
290 // align object end
291 mov(arr_size, (int32_t)base_offset_in_bytes + MinObjAlignmentInBytesMask);
292 add(arr_size, arr_size, len, ext::uxtw, f);
293 andr(arr_size, arr_size, ~MinObjAlignmentInBytesMask);
294
295 try_allocate(obj, arr_size, 0, t1, t2, slow_case);
296
297 initialize_header(obj, klass, len, t1, t2);
298
299 // Align-up to word boundary, because we clear the 4 bytes potentially
300 // following the length field in initialize_header().
301 int base_offset = align_up(base_offset_in_bytes, BytesPerWord);
302 // clear rest of allocated space
303 if (zero_array) {
304 initialize_body(obj, arr_size, base_offset, t1, t2);
305 }
306 if (Compilation::current()->bailed_out()) {
307 return;
308 }
309
310 membar(StoreStore);
311
312 if (CURRENT_ENV->dtrace_alloc_probes()) {
313 assert(obj == r0, "must be");
314 far_call(RuntimeAddress(Runtime1::entry_for(C1StubId::dtrace_object_alloc_id)));
315 }
316
317 verify_oop(obj);
318 }
319
320 void C1_MacroAssembler::build_frame(int framesize, int bang_size_in_bytes) {
321 assert(bang_size_in_bytes >= framesize, "stack bang size incorrect");
322 // Make sure there is enough stack space for this method's activation.
323 // Note that we do this before creating a frame.
324 generate_stack_overflow_check(bang_size_in_bytes);
325 MacroAssembler::build_frame(framesize);
326
327 // Insert nmethod entry barrier into frame.
328 BarrierSetAssembler* bs = BarrierSet::barrier_set()->barrier_set_assembler();
329 bs->nmethod_entry_barrier(this, nullptr /* slow_path */, nullptr /* continuation */, nullptr /* guard */);
330 }
331
332 void C1_MacroAssembler::remove_frame(int framesize) {
333 MacroAssembler::remove_frame(framesize);
334 }
335
336
337 void C1_MacroAssembler::verified_entry(bool breakAtEntry) {
338 // If we have to make this method not-entrant we'll overwrite its
339 // first instruction with a jump. For this action to be legal we
340 // must ensure that this first instruction is a B, BL, NOP, BKPT,
341 // SVC, HVC, or SMC. Make it a NOP.
342 nop();
343 }
344
345 void C1_MacroAssembler::load_parameter(int offset_in_words, Register reg) {
346 // rfp, + 0: link
347 // + 1: return address
348 // + 2: argument with offset 0
349 // + 3: argument with offset 1
350 // + 4: ...
351
352 ldr(reg, Address(rfp, (offset_in_words + 2) * BytesPerWord));
353 }
354
355 #ifndef PRODUCT
356
357 void C1_MacroAssembler::verify_stack_oop(int stack_offset) {
358 if (!VerifyOops) return;
359 verify_oop_addr(Address(sp, stack_offset));
360 }
361
362 void C1_MacroAssembler::verify_not_null_oop(Register r) {
363 if (!VerifyOops) return;
364 Label not_null;
365 cbnz(r, not_null);
366 stop("non-null oop required");
367 bind(not_null);
368 verify_oop(r);
369 }
370
371 void C1_MacroAssembler::invalidate_registers(bool inv_r0, bool inv_r19, bool inv_r2, bool inv_r3, bool inv_r4, bool inv_r5) {
372 #ifdef ASSERT
373 static int nn;
374 if (inv_r0) mov(r0, 0xDEAD);
375 if (inv_r19) mov(r19, 0xDEAD);
376 if (inv_r2) mov(r2, nn++);
377 if (inv_r3) mov(r3, 0xDEAD);
378 if (inv_r4) mov(r4, 0xDEAD);
379 if (inv_r5) mov(r5, 0xDEAD);
380 #endif
381 }
382 #endif // ifndef PRODUCT