1 /*
2 * Copyright (c) 1999, 2021, 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 scratch, Label& slow_case) {
65 const int aligned_mask = BytesPerWord -1;
66 const int hdr_offset = oopDesc::mark_offset_in_bytes();
67 assert(hdr != obj && hdr != disp_hdr && obj != disp_hdr, "registers must be different");
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(scratch != noreg, "should have scratch register at this point");
87 biased_locking_enter(disp_hdr, obj, hdr, scratch, false, done, &slow_case);
88 }
89
90 // Load object header
91 ldr(hdr, Address(obj, hdr_offset));
92 // and mark it as unlocked
93 orr(hdr, hdr, markWord::unlocked_value);
94 // save unlocked object header into the displaced header location on the stack
95 str(hdr, Address(disp_hdr, 0));
96 // test if object header is still the same (i.e. unlocked), and if so, store the
97 // displaced header address in the object header - if it is not the same, get the
98 // object header instead
99 lea(rscratch2, Address(obj, hdr_offset));
100 cmpxchgptr(hdr, disp_hdr, rscratch2, rscratch1, done, /*fallthough*/NULL);
101 // if the object header was the same, we're done
102 // if the object header was not the same, it is now in the hdr register
103 // => test if it is a stack pointer into the same stack (recursive locking), i.e.:
104 //
105 // 1) (hdr & aligned_mask) == 0
106 // 2) sp <= hdr
107 // 3) hdr <= sp + page_size
108 //
109 // these 3 tests can be done by evaluating the following expression:
110 //
111 // (hdr - sp) & (aligned_mask - page_size)
112 //
113 // assuming both the stack pointer and page_size have their least
114 // significant 2 bits cleared and page_size is a power of 2
115 mov(rscratch1, sp);
116 sub(hdr, hdr, rscratch1);
117 ands(hdr, hdr, aligned_mask - os::vm_page_size());
118 // for recursive locking, the result is zero => save it in the displaced header
119 // location (NULL in the displaced hdr location indicates recursive locking)
120 str(hdr, Address(disp_hdr, 0));
121 // otherwise we don't care about the result and handle locking via runtime call
122 cbnz(hdr, slow_case);
123 // done
124 bind(done);
125 if (PrintBiasedLockingStatistics) {
126 lea(rscratch2, ExternalAddress((address)BiasedLocking::fast_path_entry_count_addr()));
127 addmw(Address(rscratch2, 0), 1, rscratch1);
128 }
129 return null_check_offset;
130 }
131
132
133 void C1_MacroAssembler::unlock_object(Register hdr, Register obj, Register disp_hdr, Label& slow_case) {
134 const int aligned_mask = BytesPerWord -1;
135 const int hdr_offset = oopDesc::mark_offset_in_bytes();
136 assert(hdr != obj && hdr != disp_hdr && obj != disp_hdr, "registers must be different");
137 Label done;
138
139 if (UseBiasedLocking) {
140 // load object
141 ldr(obj, Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes()));
142 biased_locking_exit(obj, hdr, done);
143 }
144
145 // load displaced header
146 ldr(hdr, Address(disp_hdr, 0));
147 // if the loaded hdr is NULL we had recursive locking
148 // if we had recursive locking, we are done
149 cbz(hdr, done);
150 if (!UseBiasedLocking) {
151 // load object
152 ldr(obj, Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes()));
153 }
154 verify_oop(obj);
155 // test if object header is pointing to the displaced header, and if so, restore
156 // the displaced header in the object - if the object header is not pointing to
157 // the displaced header, get the object header instead
158 // if the object header was not pointing to the displaced header,
159 // we do unlocking via runtime call
160 if (hdr_offset) {
161 lea(rscratch1, Address(obj, hdr_offset));
162 cmpxchgptr(disp_hdr, hdr, rscratch1, rscratch2, done, &slow_case);
163 } else {
164 cmpxchgptr(disp_hdr, hdr, obj, rscratch2, done, &slow_case);
165 }
166 // done
167 bind(done);
168 }
169
170
171 // Defines obj, preserves var_size_in_bytes
172 void C1_MacroAssembler::try_allocate(Register obj, Register var_size_in_bytes, int con_size_in_bytes, Register t1, Register t2, Label& slow_case) {
173 if (UseTLAB) {
174 tlab_allocate(obj, var_size_in_bytes, con_size_in_bytes, t1, t2, slow_case);
175 } else {
176 eden_allocate(obj, var_size_in_bytes, con_size_in_bytes, t1, slow_case);
177 }
178 }
179
180 void C1_MacroAssembler::initialize_header(Register obj, Register klass, Register len, Register t1, Register t2) {
181 assert_different_registers(obj, klass, len);
182 if (UseBiasedLocking && !len->is_valid()) {
183 assert_different_registers(obj, klass, len, t1, t2);
184 ldr(t1, Address(klass, Klass::prototype_header_offset()));
185 } else {
186 // This assumes that all prototype bits fit in an int32_t
187 mov(t1, (int32_t)(intptr_t)markWord::prototype().value());
188 }
189 str(t1, Address(obj, oopDesc::mark_offset_in_bytes()));
190
191 if (UseCompressedClassPointers) { // Take care not to kill klass
192 encode_klass_not_null(t1, klass);
193 strw(t1, Address(obj, oopDesc::klass_offset_in_bytes()));
194 } else {
195 str(klass, Address(obj, oopDesc::klass_offset_in_bytes()));
196 }
197
198 if (len->is_valid()) {
199 strw(len, Address(obj, arrayOopDesc::length_offset_in_bytes()));
200 } else if (UseCompressedClassPointers) {
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 zero_words(t1, t2);
224
225 bind(done);
226 }
227
228
229 void C1_MacroAssembler::allocate_object(Register obj, Register t1, Register t2, int header_size, int object_size, Register klass, Label& slow_case) {
230 assert_different_registers(obj, t1, t2); // XXX really?
231 assert(header_size >= 0 && object_size >= header_size, "illegal sizes");
232
233 try_allocate(obj, noreg, object_size * BytesPerWord, t1, t2, slow_case);
234
235 initialize_object(obj, klass, noreg, object_size * HeapWordSize, t1, t2, UseTLAB);
236 }
237
238 // Scratch registers: t1 = r10, t2 = r11
239 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) {
240 assert((con_size_in_bytes & MinObjAlignmentInBytesMask) == 0,
241 "con_size_in_bytes is not multiple of alignment");
242 const int hdr_size_in_bytes = instanceOopDesc::header_size() * HeapWordSize;
243
244 initialize_header(obj, klass, noreg, t1, t2);
245
246 if (!(UseTLAB && ZeroTLAB && is_tlab_allocated)) {
247 // clear rest of allocated space
248 const Register index = t2;
249 if (var_size_in_bytes != noreg) {
250 mov(index, var_size_in_bytes);
251 initialize_body(obj, index, hdr_size_in_bytes, t1, t2);
252 } else if (con_size_in_bytes > hdr_size_in_bytes) {
253 con_size_in_bytes -= hdr_size_in_bytes;
254 lea(t1, Address(obj, hdr_size_in_bytes));
255 zero_words(t1, con_size_in_bytes / BytesPerWord);
256 }
257 }
258
259 membar(StoreStore);
260
261 if (CURRENT_ENV->dtrace_alloc_probes()) {
262 assert(obj == r0, "must be");
263 far_call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id)));
264 }
265
266 verify_oop(obj);
267 }
268 void C1_MacroAssembler::allocate_array(Register obj, Register len, Register t1, Register t2, int header_size, int f, Register klass, Label& slow_case) {
269 assert_different_registers(obj, len, t1, t2, klass);
270
271 // determine alignment mask
272 assert(!(BytesPerWord & 1), "must be a multiple of 2 for masking code to work");
273
274 // check for negative or excessive length
275 mov(rscratch1, (int32_t)max_array_allocation_length);
276 cmp(len, rscratch1);
277 br(Assembler::HS, slow_case);
278
279 const Register arr_size = t2; // okay to be the same
280 // align object end
281 mov(arr_size, (int32_t)header_size * BytesPerWord + MinObjAlignmentInBytesMask);
282 add(arr_size, arr_size, len, ext::uxtw, f);
283 andr(arr_size, arr_size, ~MinObjAlignmentInBytesMask);
284
285 try_allocate(obj, arr_size, 0, t1, t2, slow_case);
286
287 initialize_header(obj, klass, len, t1, t2);
288
289 // clear rest of allocated space
290 initialize_body(obj, arr_size, header_size * BytesPerWord, t1, t2);
291
292 membar(StoreStore);
293
294 if (CURRENT_ENV->dtrace_alloc_probes()) {
295 assert(obj == r0, "must be");
296 far_call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id)));
297 }
298
299 verify_oop(obj);
300 }
301
302
303 void C1_MacroAssembler::inline_cache_check(Register receiver, Register iCache) {
304 verify_oop(receiver);
305 // explicit NULL check not needed since load from [klass_offset] causes a trap
306 // check against inline cache
307 assert(!MacroAssembler::needs_explicit_null_check(oopDesc::klass_offset_in_bytes()), "must add explicit null check");
308
309 cmp_klass(receiver, iCache, rscratch1);
310 }
311
312
313 void C1_MacroAssembler::build_frame(int framesize, int bang_size_in_bytes) {
314 assert(bang_size_in_bytes >= framesize, "stack bang size incorrect");
315 // Make sure there is enough stack space for this method's activation.
316 // Note that we do this before creating a frame.
317 generate_stack_overflow_check(bang_size_in_bytes);
318 MacroAssembler::build_frame(framesize);
319
320 // Insert nmethod entry barrier into frame.
321 BarrierSetAssembler* bs = BarrierSet::barrier_set()->barrier_set_assembler();
322 bs->nmethod_entry_barrier(this);
323 }
324
325 void C1_MacroAssembler::remove_frame(int framesize) {
326 MacroAssembler::remove_frame(framesize);
327 }
328
329
330 void C1_MacroAssembler::verified_entry(bool breakAtEntry) {
331 // If we have to make this method not-entrant we'll overwrite its
332 // first instruction with a jump. For this action to be legal we
333 // must ensure that this first instruction is a B, BL, NOP, BKPT,
334 // SVC, HVC, or SMC. Make it a NOP.
335 nop();
336 }
337
338 void C1_MacroAssembler::load_parameter(int offset_in_words, Register reg) {
339 // rbp, + 0: link
340 // + 1: return address
341 // + 2: argument with offset 0
342 // + 3: argument with offset 1
343 // + 4: ...
344
345 ldr(reg, Address(rfp, (offset_in_words + 2) * BytesPerWord));
346 }
347
348 #ifndef PRODUCT
349
350 void C1_MacroAssembler::verify_stack_oop(int stack_offset) {
351 if (!VerifyOops) return;
352 verify_oop_addr(Address(sp, stack_offset), "oop");
353 }
354
355 void C1_MacroAssembler::verify_not_null_oop(Register r) {
356 if (!VerifyOops) return;
357 Label not_null;
358 cbnz(r, not_null);
359 stop("non-null oop required");
360 bind(not_null);
361 verify_oop(r);
362 }
363
364 void C1_MacroAssembler::invalidate_registers(bool inv_r0, bool inv_r19, bool inv_r2, bool inv_r3, bool inv_r4, bool inv_r5) {
365 #ifdef ASSERT
366 static int nn;
367 if (inv_r0) mov(r0, 0xDEAD);
368 if (inv_r19) mov(r19, 0xDEAD);
369 if (inv_r2) mov(r2, nn++);
370 if (inv_r3) mov(r3, 0xDEAD);
371 if (inv_r4) mov(r4, 0xDEAD);
372 if (inv_r5) mov(r5, 0xDEAD);
373 #endif
374 }
375 #endif // ifndef PRODUCT