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