1 /*
2 * Copyright (c) 1999, 2018, Oracle and/or its affiliates. All rights reserved.
3 * Copyright (c) 2014, 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 "classfile/systemDictionary.hpp"
30 #include "gc/shared/collectedHeap.hpp"
31 #include "interpreter/interpreter.hpp"
32 #include "oops/arrayOop.hpp"
33 #include "oops/markOop.hpp"
34 #include "runtime/basicLock.hpp"
35 #include "runtime/biasedLocking.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 scratch, Label& slow_case) {
64 const int aligned_mask = BytesPerWord -1;
65 const int hdr_offset = oopDesc::mark_offset_in_bytes();
66 assert(hdr != obj && hdr != disp_hdr && obj != disp_hdr, "registers must be different");
67 Label done;
68 int null_check_offset = -1;
69
70 verify_oop(obj);
71
72 // save object being locked into the BasicObjectLock
73 str(obj, Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes()));
74
75 if (UseBiasedLocking) {
76 assert(scratch != noreg, "should have scratch register at this point");
77 null_check_offset = biased_locking_enter(disp_hdr, obj, hdr, scratch, false, done, &slow_case);
78 } else {
79 null_check_offset = offset();
80 }
81
82 // Load object header
83 ldr(hdr, Address(obj, hdr_offset));
84 // and mark it as unlocked
85 orr(hdr, hdr, markOopDesc::unlocked_value);
86
87 if (EnableValhalla && !UseBiasedLocking) {
88 // Mask always_locked bit such that we go to the slow path if object is a value type
89 andr(hdr, hdr, ~markOopDesc::biased_lock_bit_in_place);
90 }
91
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 cmpxchgptr(hdr, disp_hdr, rscratch2, rscratch1, done, /*fallthough*/NULL);
99 // if the object header was the same, we're done
100 // if the object header was not the same, it is now in the hdr register
101 // => test if it is a stack pointer into the same stack (recursive locking), i.e.:
102 //
103 // 1) (hdr & aligned_mask) == 0
104 // 2) sp <= hdr
105 // 3) hdr <= sp + page_size
106 //
107 // these 3 tests can be done by evaluating the following expression:
108 //
109 // (hdr - sp) & (aligned_mask - page_size)
110 //
111 // assuming both the stack pointer and page_size have their least
112 // significant 2 bits cleared and page_size is a power of 2
113 mov(rscratch1, sp);
114 sub(hdr, hdr, rscratch1);
115 ands(hdr, hdr, aligned_mask - os::vm_page_size());
116 // for recursive locking, the result is zero => save it in the displaced header
117 // location (NULL in the displaced hdr location indicates recursive locking)
118 str(hdr, Address(disp_hdr, 0));
119 // otherwise we don't care about the result and handle locking via runtime call
120 cbnz(hdr, slow_case);
121 // done
122 bind(done);
123 if (PrintBiasedLockingStatistics) {
124 lea(rscratch2, ExternalAddress((address)BiasedLocking::fast_path_entry_count_addr()));
125 addmw(Address(rscratch2, 0), 1, rscratch1);
126 }
127 return null_check_offset;
128 }
129
130
131 void C1_MacroAssembler::unlock_object(Register hdr, Register obj, Register disp_hdr, Label& slow_case) {
132 const int aligned_mask = BytesPerWord -1;
133 const int hdr_offset = oopDesc::mark_offset_in_bytes();
134 assert(hdr != obj && hdr != disp_hdr && obj != disp_hdr, "registers must be different");
135 Label done;
136
137 if (UseBiasedLocking) {
138 // load object
139 ldr(obj, Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes()));
140 biased_locking_exit(obj, hdr, done);
141 }
142
143 // load displaced header
144 ldr(hdr, Address(disp_hdr, 0));
145 // if the loaded hdr is NULL we had recursive locking
146 // if we had recursive locking, we are done
147 cbz(hdr, done);
148 if (!UseBiasedLocking) {
149 // load object
150 ldr(obj, Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes()));
151 }
152 verify_oop(obj);
153 // test if object header is pointing to the displaced header, and if so, restore
154 // the displaced header in the object - if the object header is not pointing to
155 // the displaced header, get the object header instead
156 // if the object header was not pointing to the displaced header,
157 // we do unlocking via runtime call
158 if (hdr_offset) {
159 lea(rscratch1, Address(obj, hdr_offset));
160 cmpxchgptr(disp_hdr, hdr, rscratch1, rscratch2, done, &slow_case);
161 } else {
162 cmpxchgptr(disp_hdr, hdr, obj, rscratch2, done, &slow_case);
163 }
164 // done
165 bind(done);
166 }
167
168
169 // Defines obj, preserves var_size_in_bytes
170 void C1_MacroAssembler::try_allocate(Register obj, Register var_size_in_bytes, int con_size_in_bytes, Register t1, Register t2, Label& slow_case) {
171 if (UseTLAB) {
172 tlab_allocate(obj, var_size_in_bytes, con_size_in_bytes, t1, t2, slow_case);
173 } else {
174 eden_allocate(obj, var_size_in_bytes, con_size_in_bytes, t1, slow_case);
175 }
176 }
177
178 void C1_MacroAssembler::initialize_header(Register obj, Register klass, Register len, Register t1, Register t2) {
179 assert_different_registers(obj, klass, len);
180 if (UseBiasedLocking && !len->is_valid()) {
181 assert_different_registers(obj, klass, len, t1, t2);
182 ldr(t1, Address(klass, Klass::prototype_header_offset()));
183 } else {
184 // This assumes that all prototype bits fit in an int32_t
185 mov(t1, (int32_t)(intptr_t)markOopDesc::prototype());
186 }
187 str(t1, Address(obj, oopDesc::mark_offset_in_bytes()));
188
189 if (UseCompressedClassPointers) { // Take care not to kill klass
190 encode_klass_not_null(t1, klass);
191 strw(t1, Address(obj, oopDesc::klass_offset_in_bytes()));
192 } else {
193 str(klass, Address(obj, oopDesc::klass_offset_in_bytes()));
194 }
195
196 if (len->is_valid()) {
197 strw(len, Address(obj, arrayOopDesc::length_offset_in_bytes()));
198 } else if (UseCompressedClassPointers) {
199 store_klass_gap(obj, zr);
200 }
201 }
202
203 // preserves obj, destroys len_in_bytes
204 void C1_MacroAssembler::initialize_body(Register obj, Register len_in_bytes, int hdr_size_in_bytes, Register t1) {
205 assert(hdr_size_in_bytes >= 0, "header size must be positive or 0");
206 Label done;
207
208 // len_in_bytes is positive and ptr sized
209 subs(len_in_bytes, len_in_bytes, hdr_size_in_bytes);
210 br(Assembler::EQ, done);
211
212 // Preserve obj
213 if (hdr_size_in_bytes)
214 add(obj, obj, hdr_size_in_bytes);
215 zero_memory(obj, len_in_bytes, t1);
216 if (hdr_size_in_bytes)
217 sub(obj, obj, hdr_size_in_bytes);
218
219 bind(done);
220 }
221
222
223 void C1_MacroAssembler::allocate_object(Register obj, Register t1, Register t2, int header_size, int object_size, Register klass, Label& slow_case) {
224 assert_different_registers(obj, t1, t2); // XXX really?
225 assert(header_size >= 0 && object_size >= header_size, "illegal sizes");
226
227 try_allocate(obj, noreg, object_size * BytesPerWord, t1, t2, slow_case);
228
229 initialize_object(obj, klass, noreg, object_size * HeapWordSize, t1, t2, UseTLAB);
230 }
231
232 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) {
233 assert((con_size_in_bytes & MinObjAlignmentInBytesMask) == 0,
234 "con_size_in_bytes is not multiple of alignment");
235 const int hdr_size_in_bytes = instanceOopDesc::header_size() * HeapWordSize;
236
237 initialize_header(obj, klass, noreg, t1, t2);
238
239 if (!(UseTLAB && ZeroTLAB && is_tlab_allocated)) {
240 // clear rest of allocated space
241 const Register index = t2;
242 const int threshold = 16 * BytesPerWord; // approximate break even point for code size (see comments below)
243 if (var_size_in_bytes != noreg) {
244 mov(index, var_size_in_bytes);
245 initialize_body(obj, index, hdr_size_in_bytes, t1);
246 } else if (con_size_in_bytes <= threshold) {
247 // use explicit null stores
248 int i = hdr_size_in_bytes;
249 if (i < con_size_in_bytes && (con_size_in_bytes % (2 * BytesPerWord))) {
250 str(zr, Address(obj, i));
251 i += BytesPerWord;
252 }
253 for (; i < con_size_in_bytes; i += 2 * BytesPerWord)
254 stp(zr, zr, Address(obj, i));
255 } else if (con_size_in_bytes > hdr_size_in_bytes) {
256 block_comment("zero memory");
257 // use loop to null out the fields
258
259 int words = (con_size_in_bytes - hdr_size_in_bytes) / BytesPerWord;
260 mov(index, words / 8);
261
262 const int unroll = 8; // Number of str(zr) instructions we'll unroll
263 int remainder = words % unroll;
264 lea(rscratch1, Address(obj, hdr_size_in_bytes + remainder * BytesPerWord));
265
266 Label entry_point, loop;
267 b(entry_point);
268
269 bind(loop);
270 sub(index, index, 1);
271 for (int i = -unroll; i < 0; i++) {
272 if (-i == remainder)
273 bind(entry_point);
274 str(zr, Address(rscratch1, i * wordSize));
275 }
276 if (remainder == 0)
277 bind(entry_point);
278 add(rscratch1, rscratch1, unroll * wordSize);
279 cbnz(index, loop);
280
281 }
282 }
283
284 membar(StoreStore);
285
286 if (CURRENT_ENV->dtrace_alloc_probes()) {
287 assert(obj == r0, "must be");
288 far_call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id)));
289 }
290
291 verify_oop(obj);
292 }
293 void C1_MacroAssembler::allocate_array(Register obj, Register len, Register t1, Register t2, int header_size, int f, Register klass, Label& slow_case) {
294 assert_different_registers(obj, len, t1, t2, klass);
295
296 // determine alignment mask
297 assert(!(BytesPerWord & 1), "must be a multiple of 2 for masking code to work");
298
299 // check for negative or excessive length
300 mov(rscratch1, (int32_t)max_array_allocation_length);
301 cmp(len, rscratch1);
302 br(Assembler::HS, slow_case);
303
304 const Register arr_size = t2; // okay to be the same
305 // align object end
306 mov(arr_size, (int32_t)header_size * BytesPerWord + MinObjAlignmentInBytesMask);
307 add(arr_size, arr_size, len, ext::uxtw, f);
308 andr(arr_size, arr_size, ~MinObjAlignmentInBytesMask);
309
310 try_allocate(obj, arr_size, 0, t1, t2, slow_case);
311
312 initialize_header(obj, klass, len, t1, t2);
313
314 // clear rest of allocated space
315 const Register len_zero = len;
316 initialize_body(obj, arr_size, header_size * BytesPerWord, len_zero);
317
318 membar(StoreStore);
319
320 if (CURRENT_ENV->dtrace_alloc_probes()) {
321 assert(obj == r0, "must be");
322 far_call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id)));
323 }
324
325 verify_oop(obj);
326 }
327
328
329 void C1_MacroAssembler::inline_cache_check(Register receiver, Register iCache) {
330 verify_oop(receiver);
331 // explicit NULL check not needed since load from [klass_offset] causes a trap
332 // check against inline cache
333 assert(!MacroAssembler::needs_explicit_null_check(oopDesc::klass_offset_in_bytes()), "must add explicit null check");
334
335 cmp_klass(receiver, iCache, rscratch1);
336 }
337
338
339 void C1_MacroAssembler::build_frame(int framesize, int bang_size_in_bytes) {
340 // If we have to make this method not-entrant we'll overwrite its
341 // first instruction with a jump. For this action to be legal we
342 // must ensure that this first instruction is a B, BL, NOP, BKPT,
343 // SVC, HVC, or SMC. Make it a NOP.
344 nop();
345 assert(bang_size_in_bytes >= framesize, "stack bang size incorrect");
346 // Make sure there is enough stack space for this method's activation.
347 // Note that we do this before doing an enter().
348 generate_stack_overflow_check(bang_size_in_bytes);
349 MacroAssembler::build_frame(framesize + 2 * wordSize);
350 if (NotifySimulator) {
351 notify(Assembler::method_entry);
352 }
353 }
354
355 void C1_MacroAssembler::remove_frame(int framesize) {
356 MacroAssembler::remove_frame(framesize + 2 * wordSize);
357 if (NotifySimulator) {
358 notify(Assembler::method_reentry);
359 }
360 }
361
362
363 void C1_MacroAssembler::verified_entry() {
364 }
365
366 void C1_MacroAssembler::load_parameter(int offset_in_words, Register reg) {
367 // rbp, + 0: link
368 // + 1: return address
369 // + 2: argument with offset 0
370 // + 3: argument with offset 1
371 // + 4: ...
372
373 ldr(reg, Address(rfp, (offset_in_words + 2) * BytesPerWord));
374 }
375
376 #ifndef PRODUCT
377
378 void C1_MacroAssembler::verify_stack_oop(int stack_offset) {
379 if (!VerifyOops) return;
380 verify_oop_addr(Address(sp, stack_offset), "oop");
381 }
382
383 void C1_MacroAssembler::verify_not_null_oop(Register r) {
384 if (!VerifyOops) return;
385 Label not_null;
386 cbnz(r, not_null);
387 stop("non-null oop required");
388 bind(not_null);
389 verify_oop(r);
390 }
391
392 void C1_MacroAssembler::invalidate_registers(bool inv_r0, bool inv_r19, bool inv_r2, bool inv_r3, bool inv_r4, bool inv_r5) {
393 #ifdef ASSERT
394 static int nn;
395 if (inv_r0) mov(r0, 0xDEAD);
396 if (inv_r19) mov(r19, 0xDEAD);
397 if (inv_r2) mov(r2, nn++);
398 if (inv_r3) mov(r3, 0xDEAD);
399 if (inv_r4) mov(r4, 0xDEAD);
400 if (inv_r5) mov(r5, 0xDEAD);
401 #endif
402 }
403 #endif // ifndef PRODUCT