1 /*
2 * Copyright (c) 1999, 2024, Oracle and/or its affiliates. All rights reserved.
3 * Copyright (c) 2012, 2024 SAP SE. 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 "asm/macroAssembler.inline.hpp"
28 #include "c1/c1_MacroAssembler.hpp"
29 #include "c1/c1_Runtime1.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 #include "utilities/align.hpp"
40 #include "utilities/macros.hpp"
41 #include "utilities/powerOfTwo.hpp"
42
43
44 void C1_MacroAssembler::explicit_null_check(Register base) {
45 Unimplemented();
46 }
47
48
49 void C1_MacroAssembler::build_frame(int frame_size_in_bytes, int bang_size_in_bytes) {
50 // Avoid stack bang as first instruction. It may get overwritten by patch_verified_entry.
51 const Register return_pc = R20;
52 mflr(return_pc);
53
54 // Make sure there is enough stack space for this method's activation.
55 assert(bang_size_in_bytes >= frame_size_in_bytes, "stack bang size incorrect");
56 generate_stack_overflow_check(bang_size_in_bytes);
57
58 std(return_pc, _abi0(lr), R1_SP); // SP->lr = return_pc
59 push_frame(frame_size_in_bytes, R0); // SP -= frame_size_in_bytes
60
61 BarrierSetAssembler* bs = BarrierSet::barrier_set()->barrier_set_assembler();
62 bs->nmethod_entry_barrier(this, R20);
63 }
64
65
66 void C1_MacroAssembler::verified_entry(bool breakAtEntry) {
67 if (breakAtEntry) illtrap();
68 // build frame
69 }
70
71
72 void C1_MacroAssembler::lock_object(Register Rmark, Register Roop, Register Rbox, Register Rscratch, Label& slow_case) {
73 assert_different_registers(Rmark, Roop, Rbox, Rscratch);
74
75 Label done, cas_failed, slow_int;
76
77 // The following move must be the first instruction of emitted since debug
78 // information may be generated for it.
79 // Load object header.
80 ld(Rmark, oopDesc::mark_offset_in_bytes(), Roop);
81
82 verify_oop(Roop, FILE_AND_LINE);
83
84 // Save object being locked into the BasicObjectLock...
85 std(Roop, in_bytes(BasicObjectLock::obj_offset()), Rbox);
86
87 if (DiagnoseSyncOnValueBasedClasses != 0) {
88 load_klass(Rscratch, Roop);
89 lbz(Rscratch, in_bytes(Klass::misc_flags_offset()), Rscratch);
90 testbitdi(CCR0, R0, Rscratch, exact_log2(KlassFlags::_misc_is_value_based_class));
91 bne(CCR0, slow_int);
92 }
93
94 if (LockingMode == LM_LIGHTWEIGHT) {
95 lightweight_lock(Rbox, Roop, Rmark, Rscratch, slow_int);
96 } else if (LockingMode == LM_LEGACY) {
97 // ... and mark it unlocked.
98 ori(Rmark, Rmark, markWord::unlocked_value);
99
100 // Save unlocked object header into the displaced header location on the stack.
101 std(Rmark, BasicLock::displaced_header_offset_in_bytes(), Rbox);
102
103 // Compare object markWord with Rmark and if equal exchange Rscratch with object markWord.
104 assert(oopDesc::mark_offset_in_bytes() == 0, "cas must take a zero displacement");
105 cmpxchgd(/*flag=*/CCR0,
106 /*current_value=*/Rscratch,
107 /*compare_value=*/Rmark,
108 /*exchange_value=*/Rbox,
109 /*where=*/Roop/*+0==mark_offset_in_bytes*/,
110 MacroAssembler::MemBarRel | MacroAssembler::MemBarAcq,
111 MacroAssembler::cmpxchgx_hint_acquire_lock(),
112 noreg,
113 &cas_failed,
114 /*check without membar and ldarx first*/true);
115 // If compare/exchange succeeded we found an unlocked object and we now have locked it
116 // hence we are done.
117 } else {
118 assert(false, "Unhandled LockingMode:%d", LockingMode);
119 }
120 b(done);
121
122 bind(slow_int);
123 b(slow_case); // far
124
125 if (LockingMode == LM_LEGACY) {
126 bind(cas_failed);
127 // We did not find an unlocked object so see if this is a recursive case.
128 sub(Rscratch, Rscratch, R1_SP);
129 load_const_optimized(R0, (~(os::vm_page_size()-1) | markWord::lock_mask_in_place));
130 and_(R0/*==0?*/, Rscratch, R0);
131 std(R0/*==0, perhaps*/, BasicLock::displaced_header_offset_in_bytes(), Rbox);
132 bne(CCR0, slow_int);
133 }
134
135 bind(done);
136 if (LockingMode == LM_LEGACY) {
137 inc_held_monitor_count(Rmark /*tmp*/);
138 }
139 }
140
141
142 void C1_MacroAssembler::unlock_object(Register Rmark, Register Roop, Register Rbox, Label& slow_case) {
143 assert_different_registers(Rmark, Roop, Rbox);
144
145 Label slow_int, done;
146
147 Address mark_addr(Roop, oopDesc::mark_offset_in_bytes());
148 assert(mark_addr.disp() == 0, "cas must take a zero displacement");
149
150 if (LockingMode != LM_LIGHTWEIGHT) {
151 // Test first if it is a fast recursive unlock.
152 ld(Rmark, BasicLock::displaced_header_offset_in_bytes(), Rbox);
153 cmpdi(CCR0, Rmark, 0);
154 beq(CCR0, done);
155 }
156
157 // Load object.
158 ld(Roop, in_bytes(BasicObjectLock::obj_offset()), Rbox);
159 verify_oop(Roop, FILE_AND_LINE);
160
161 if (LockingMode == LM_LIGHTWEIGHT) {
162 lightweight_unlock(Roop, Rmark, slow_int);
163 } else if (LockingMode == LM_LEGACY) {
164 // Check if it is still a light weight lock, this is is true if we see
165 // the stack address of the basicLock in the markWord of the object.
166 cmpxchgd(/*flag=*/CCR0,
167 /*current_value=*/R0,
168 /*compare_value=*/Rbox,
169 /*exchange_value=*/Rmark,
170 /*where=*/Roop,
171 MacroAssembler::MemBarRel,
172 MacroAssembler::cmpxchgx_hint_release_lock(),
173 noreg,
174 &slow_int);
175 } else {
176 assert(false, "Unhandled LockingMode:%d", LockingMode);
177 }
178 b(done);
179 bind(slow_int);
180 b(slow_case); // far
181
182 // Done
183 bind(done);
184 if (LockingMode == LM_LEGACY) {
185 dec_held_monitor_count(Rmark /*tmp*/);
186 }
187 }
188
189
190 void C1_MacroAssembler::try_allocate(
191 Register obj, // result: pointer to object after successful allocation
192 Register var_size_in_bytes, // object size in bytes if unknown at compile time; invalid otherwise
193 int con_size_in_bytes, // object size in bytes if known at compile time
194 Register t1, // temp register
195 Register t2, // temp register
196 Label& slow_case // continuation point if fast allocation fails
197 ) {
198 if (UseTLAB) {
199 tlab_allocate(obj, var_size_in_bytes, con_size_in_bytes, t1, slow_case);
200 } else {
201 b(slow_case);
202 }
203 }
204
205
206 void C1_MacroAssembler::initialize_header(Register obj, Register klass, Register len, Register t1, Register t2) {
207 assert_different_registers(obj, klass, len, t1, t2);
208 load_const_optimized(t1, (intx)markWord::prototype().value());
209 std(t1, oopDesc::mark_offset_in_bytes(), obj);
210 store_klass(obj, klass);
211 if (len->is_valid()) {
212 stw(len, arrayOopDesc::length_offset_in_bytes(), obj);
213 } else if (UseCompressedClassPointers) {
214 // Otherwise length is in the class gap.
215 store_klass_gap(obj);
216 }
217 }
218
219
220 void C1_MacroAssembler::initialize_body(Register base, Register index) {
221 assert_different_registers(base, index);
222 srdi(index, index, LogBytesPerWord);
223 clear_memory_doubleword(base, index);
224 }
225
226 void C1_MacroAssembler::initialize_body(Register obj, Register tmp1, Register tmp2,
227 int obj_size_in_bytes, int hdr_size_in_bytes) {
228 const int index = (obj_size_in_bytes - hdr_size_in_bytes) / HeapWordSize;
229
230 // 2x unrolled loop is shorter with more than 9 HeapWords.
231 if (index <= 9) {
232 clear_memory_unrolled(obj, index, R0, hdr_size_in_bytes);
233 } else {
234 const Register base_ptr = tmp1,
235 cnt_dwords = tmp2;
236
237 addi(base_ptr, obj, hdr_size_in_bytes); // Compute address of first element.
238 clear_memory_doubleword(base_ptr, cnt_dwords, R0, index);
239 }
240 }
241
242 void C1_MacroAssembler::allocate_object(
243 Register obj, // result: pointer to object after successful allocation
244 Register t1, // temp register
245 Register t2, // temp register
246 Register t3, // temp register
247 int hdr_size, // object header size in words
248 int obj_size, // object size in words
249 Register klass, // object klass
250 Label& slow_case // continuation point if fast allocation fails
251 ) {
252 assert_different_registers(obj, t1, t2, t3, klass);
253
254 // allocate space & initialize header
255 if (!is_simm16(obj_size * wordSize)) {
256 // Would need to use extra register to load
257 // object size => go the slow case for now.
258 b(slow_case);
259 return;
260 }
261 try_allocate(obj, noreg, obj_size * wordSize, t2, t3, slow_case);
262
263 initialize_object(obj, klass, noreg, obj_size * HeapWordSize, t1, t2);
264 }
265
266 void C1_MacroAssembler::initialize_object(
267 Register obj, // result: pointer to object after successful allocation
268 Register klass, // object klass
269 Register var_size_in_bytes, // object size in bytes if unknown at compile time; invalid otherwise
270 int con_size_in_bytes, // object size in bytes if known at compile time
271 Register t1, // temp register
272 Register t2 // temp register
273 ) {
274 const int hdr_size_in_bytes = instanceOopDesc::header_size() * HeapWordSize;
275
276 initialize_header(obj, klass, noreg, t1, t2);
277
278 #ifdef ASSERT
279 {
280 lwz(t1, in_bytes(Klass::layout_helper_offset()), klass);
281 if (var_size_in_bytes != noreg) {
282 cmpw(CCR0, t1, var_size_in_bytes);
283 } else {
284 cmpwi(CCR0, t1, con_size_in_bytes);
285 }
286 asm_assert_eq("bad size in initialize_object");
287 }
288 #endif
289
290 // Initialize body.
291 if (var_size_in_bytes != noreg) {
292 // Use a loop.
293 addi(t1, obj, hdr_size_in_bytes); // Compute address of first element.
294 addi(t2, var_size_in_bytes, -hdr_size_in_bytes); // Compute size of body.
295 initialize_body(t1, t2);
296 } else if (con_size_in_bytes > hdr_size_in_bytes) {
297 // Use a loop.
298 initialize_body(obj, t1, t2, con_size_in_bytes, hdr_size_in_bytes);
299 }
300
301 if (CURRENT_ENV->dtrace_alloc_probes()) {
302 Unimplemented();
303 // assert(obj == O0, "must be");
304 // call(CAST_FROM_FN_PTR(address, Runtime1::entry_for(C1StubId::dtrace_object_alloc_id)),
305 // relocInfo::runtime_call_type);
306 }
307
308 verify_oop(obj, FILE_AND_LINE);
309 }
310
311
312 void C1_MacroAssembler::allocate_array(
313 Register obj, // result: pointer to array after successful allocation
314 Register len, // array length
315 Register t1, // temp register
316 Register t2, // temp register
317 Register t3, // temp register
318 int base_offset_in_bytes, // elements offset in bytes
319 int elt_size, // element size in bytes
320 Register klass, // object klass
321 Label& slow_case, // continuation point if fast allocation fails
322 bool zero_array // zero the allocated array or not
323 ) {
324 assert_different_registers(obj, len, t1, t2, t3, klass);
325
326 // Determine alignment mask.
327 assert(!(BytesPerWord & 1), "must be a multiple of 2 for masking code to work");
328 int log2_elt_size = exact_log2(elt_size);
329
330 // Check for negative or excessive length.
331 size_t max_length = max_array_allocation_length >> log2_elt_size;
332 if (UseTLAB) {
333 size_t max_tlab = align_up(ThreadLocalAllocBuffer::max_size() >> log2_elt_size, 64*K);
334 if (max_tlab < max_length) { max_length = max_tlab; }
335 }
336 load_const_optimized(t1, max_length);
337 cmpld(CCR0, len, t1);
338 bc_far_optimized(Assembler::bcondCRbiIs1, bi0(CCR0, Assembler::greater), slow_case);
339
340 // compute array size
341 // note: If 0 <= len <= max_length, len*elt_size + header + alignment is
342 // smaller or equal to the largest integer; also, since top is always
343 // aligned, we can do the alignment here instead of at the end address
344 // computation.
345 const Register arr_size = t1;
346 Register arr_len_in_bytes = len;
347 if (elt_size != 1) {
348 sldi(t1, len, log2_elt_size);
349 arr_len_in_bytes = t1;
350 }
351 addi(arr_size, arr_len_in_bytes, base_offset_in_bytes + MinObjAlignmentInBytesMask); // Add space for header & alignment.
352 clrrdi(arr_size, arr_size, LogMinObjAlignmentInBytes); // Align array size.
353
354 // Allocate space & initialize header.
355 try_allocate(obj, arr_size, 0, t2, t3, slow_case);
356 initialize_header(obj, klass, len, t2, t3);
357
358 if (zero_array) {
359 // Initialize body.
360 const Register base = t2;
361 const Register index = t3;
362 addi(base, obj, base_offset_in_bytes); // compute address of first element
363 addi(index, arr_size, -(base_offset_in_bytes)); // compute index = number of bytes to clear
364
365 // Zero first 4 bytes, if start offset is not word aligned.
366 if (!is_aligned(base_offset_in_bytes, BytesPerWord)) {
367 assert(is_aligned(base_offset_in_bytes, BytesPerInt), "must be 4-byte aligned");
368 li(t1, 0);
369 stw(t1, 0, base);
370 addi(base, base, BytesPerInt);
371 // Note: initialize_body will align index down, no need to correct it here.
372 }
373
374 initialize_body(base, index);
375 }
376
377 if (CURRENT_ENV->dtrace_alloc_probes()) {
378 Unimplemented();
379 //assert(obj == O0, "must be");
380 //call(CAST_FROM_FN_PTR(address, Runtime1::entry_for(C1StubId::dtrace_object_alloc_id)),
381 // relocInfo::runtime_call_type);
382 }
383
384 verify_oop(obj, FILE_AND_LINE);
385 }
386
387
388 #ifndef PRODUCT
389
390 void C1_MacroAssembler::verify_stack_oop(int stack_offset) {
391 verify_oop_addr((RegisterOrConstant)stack_offset, R1_SP, "broken oop in stack slot");
392 }
393
394 void C1_MacroAssembler::verify_not_null_oop(Register r) {
395 Label not_null;
396 cmpdi(CCR0, r, 0);
397 bne(CCR0, not_null);
398 stop("non-null oop required");
399 bind(not_null);
400 verify_oop(r, FILE_AND_LINE);
401 }
402
403 #endif // PRODUCT
404
405 void C1_MacroAssembler::null_check(Register r, Label* Lnull) {
406 if (TrapBasedNullChecks) { // SIGTRAP based
407 trap_null_check(r);
408 } else { // explicit
409 //const address exception_entry = Runtime1::entry_for(C1StubId::throw_null_pointer_exception_id);
410 assert(Lnull != nullptr, "must have Label for explicit check");
411 cmpdi(CCR0, r, 0);
412 bc_far_optimized(Assembler::bcondCRbiIs1, bi0(CCR0, Assembler::equal), *Lnull);
413 }
414 }