1 /*
2 * Copyright (c) 2013, Red Hat Inc.
3 * Copyright (c) 1999, 2011, Oracle and/or its affiliates.
4 * All rights reserved.
5 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
6 *
7 * This code is free software; you can redistribute it and/or modify it
8 * under the terms of the GNU General Public License version 2 only, as
9 * published by the Free Software Foundation.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 *
25 */
26
27 #include "precompiled.hpp"
28 #include "c1/c1_MacroAssembler.hpp"
29 #include "c1/c1_Runtime1.hpp"
30 #include "classfile/systemDictionary.hpp"
31 #include "gc_interface/collectedHeap.hpp"
32 #include "interpreter/interpreter.hpp"
33 #include "oops/arrayOop.hpp"
34 #include "oops/markOop.hpp"
35 #include "runtime/basicLock.hpp"
36 #include "runtime/biasedLocking.hpp"
37 #include "runtime/os.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, fail;
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 // save unlocked object header into the displaced header location on the stack
87 str(hdr, Address(disp_hdr, 0));
88 // test if object header is still the same (i.e. unlocked), and if so, store the
89 // displaced header address in the object header - if it is not the same, get the
90 // object header instead
91 lea(rscratch2, Address(obj, hdr_offset));
92 cmpxchgptr(hdr, disp_hdr, rscratch2, rscratch1, done, /*fallthough*/NULL);
93 // if the object header was the same, we're done
94 // if the object header was not the same, it is now in the hdr register
95 // => test if it is a stack pointer into the same stack (recursive locking), i.e.:
96 //
97 // 1) (hdr & aligned_mask) == 0
98 // 2) sp <= hdr
99 // 3) hdr <= sp + page_size
100 //
101 // these 3 tests can be done by evaluating the following expression:
102 //
103 // (hdr - sp) & (aligned_mask - page_size)
104 //
105 // assuming both the stack pointer and page_size have their least
106 // significant 2 bits cleared and page_size is a power of 2
107 mov(rscratch1, sp);
108 sub(hdr, hdr, rscratch1);
109 ands(hdr, hdr, aligned_mask - os::vm_page_size());
110 // for recursive locking, the result is zero => save it in the displaced header
111 // location (NULL in the displaced hdr location indicates recursive locking)
112 str(hdr, Address(disp_hdr, 0));
113 // otherwise we don't care about the result and handle locking via runtime call
114 cbnz(hdr, slow_case);
115 // done
116 bind(done);
117 if (PrintBiasedLockingStatistics) {
118 lea(rscratch2, ExternalAddress((address)BiasedLocking::fast_path_entry_count_addr()));
119 addmw(Address(rscratch2, 0), 1, rscratch1);
120 }
121 return null_check_offset;
122 }
123
124
125 void C1_MacroAssembler::unlock_object(Register hdr, Register obj, Register disp_hdr, Label& slow_case) {
126 const int aligned_mask = BytesPerWord -1;
127 const int hdr_offset = oopDesc::mark_offset_in_bytes();
128 assert(hdr != obj && hdr != disp_hdr && obj != disp_hdr, "registers must be different");
129 Label done;
130
131 if (UseBiasedLocking) {
132 // load object
133 ldr(obj, Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes()));
134 biased_locking_exit(obj, hdr, done);
135 }
136
137 // load displaced header
138 ldr(hdr, Address(disp_hdr, 0));
139 // if the loaded hdr is NULL we had recursive locking
140 // if we had recursive locking, we are done
141 cbz(hdr, done);
142 if (!UseBiasedLocking) {
143 // load object
144 ldr(obj, Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes()));
145 }
146 verify_oop(obj);
147 // test if object header is pointing to the displaced header, and if so, restore
148 // the displaced header in the object - if the object header is not pointing to
149 // the displaced header, get the object header instead
150 // if the object header was not pointing to the displaced header,
151 // we do unlocking via runtime call
152 if (hdr_offset) {
153 lea(rscratch1, Address(obj, hdr_offset));
154 cmpxchgptr(disp_hdr, hdr, rscratch1, rscratch2, done, &slow_case);
155 } else {
156 cmpxchgptr(disp_hdr, hdr, obj, rscratch2, done, &slow_case);
157 }
158 // done
159 bind(done);
160 }
161
162
163 // Defines obj, preserves var_size_in_bytes
164 void C1_MacroAssembler::try_allocate(Register obj, Register var_size_in_bytes, int con_size_in_bytes, Register t1, Register t2, Label& slow_case) {
165 if (UseTLAB) {
166 tlab_allocate(obj, var_size_in_bytes, con_size_in_bytes, t1, t2, slow_case);
167 } else {
168 eden_allocate(obj, var_size_in_bytes, con_size_in_bytes, t1, slow_case);
169 incr_allocated_bytes(noreg, var_size_in_bytes, con_size_in_bytes, t1);
170 }
171 }
172
173 void C1_MacroAssembler::initialize_header(Register obj, Register klass, Register len, Register t1, Register t2) {
174 assert_different_registers(obj, klass, len);
175 if (UseBiasedLocking && !len->is_valid()) {
176 assert_different_registers(obj, klass, len, t1, t2);
177 ldr(t1, Address(klass, Klass::prototype_header_offset()));
178 } else {
179 // This assumes that all prototype bits fit in an int32_t
180 mov(t1, (int32_t)(intptr_t)markOopDesc::prototype());
181 }
182 str(t1, Address(obj, oopDesc::mark_offset_in_bytes()));
183
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 if (len->is_valid()) {
192 strw(len, Address(obj, arrayOopDesc::length_offset_in_bytes()));
193 } else if (UseCompressedClassPointers) {
194 store_klass_gap(obj, zr);
195 }
196 }
197
198 // Zero words; len is in bytes
199 // Destroys all registers except addr
200 // len must be a nonzero multiple of wordSize
201 void C1_MacroAssembler::zero_memory(Register addr, Register len, Register t1) {
202 assert_different_registers(addr, len, t1, rscratch1, rscratch2);
203
204 #ifdef ASSERT
205 { Label L;
206 tst(len, BytesPerWord - 1);
207 br(Assembler::EQ, L);
208 stop("len is not a multiple of BytesPerWord");
209 bind(L);
210 }
211 #endif
212
213 #ifndef PRODUCT
214 block_comment("zero memory");
215 #endif
216
217 Label loop;
218 Label entry;
219
220 // Algorithm:
221 //
222 // scratch1 = cnt & 7;
223 // cnt -= scratch1;
224 // p += scratch1;
225 // switch (scratch1) {
226 // do {
227 // cnt -= 8;
228 // p[-8] = 0;
229 // case 7:
230 // p[-7] = 0;
231 // case 6:
232 // p[-6] = 0;
233 // // ...
234 // case 1:
235 // p[-1] = 0;
236 // case 0:
237 // p += 8;
238 // } while (cnt);
239 // }
240
241 const int unroll = 8; // Number of str(zr) instructions we'll unroll
242
243 lsr(len, len, LogBytesPerWord);
244 andr(rscratch1, len, unroll - 1); // tmp1 = cnt % unroll
245 sub(len, len, rscratch1); // cnt -= unroll
246 // t1 always points to the end of the region we're about to zero
247 add(t1, addr, rscratch1, Assembler::LSL, LogBytesPerWord);
248 adr(rscratch2, entry);
249 sub(rscratch2, rscratch2, rscratch1, Assembler::LSL, 2);
250 br(rscratch2);
251 bind(loop);
252 sub(len, len, unroll);
253 for (int i = -unroll; i < 0; i++)
254 str(zr, Address(t1, i * wordSize));
255 bind(entry);
256 add(t1, t1, unroll * wordSize);
257 cbnz(len, loop);
258 }
259
260 // preserves obj, destroys len_in_bytes
261 void C1_MacroAssembler::initialize_body(Register obj, Register len_in_bytes, int hdr_size_in_bytes, Register t1) {
262 Label done;
263 assert(obj != len_in_bytes && obj != t1 && t1 != len_in_bytes, "registers must be different");
264 assert((hdr_size_in_bytes & (BytesPerWord - 1)) == 0, "header size is not a multiple of BytesPerWord");
265 Register index = len_in_bytes;
266 // index is positive and ptr sized
267 subs(index, index, hdr_size_in_bytes);
268 br(Assembler::EQ, done);
269 // note: for the remaining code to work, index must be a multiple of BytesPerWord
270 #ifdef ASSERT
271 { Label L;
272 tst(index, BytesPerWord - 1);
273 br(Assembler::EQ, L);
274 stop("index is not a multiple of BytesPerWord");
275 bind(L);
276 }
277 #endif
278
279 // Preserve obj
280 if (hdr_size_in_bytes)
281 add(obj, obj, hdr_size_in_bytes);
282 zero_memory(obj, index, t1);
283 if (hdr_size_in_bytes)
284 sub(obj, obj, hdr_size_in_bytes);
285
286 // done
287 bind(done);
288 }
289
290
291 void C1_MacroAssembler::allocate_object(Register obj, Register t1, Register t2, int header_size, int object_size, Register klass, Label& slow_case) {
292 assert_different_registers(obj, t1, t2); // XXX really?
293 assert(header_size >= 0 && object_size >= header_size, "illegal sizes");
294
295 try_allocate(obj, noreg, object_size * BytesPerWord, t1, t2, slow_case);
296
297 initialize_object(obj, klass, noreg, object_size * HeapWordSize, t1, t2);
298 }
299
300 void C1_MacroAssembler::initialize_object(Register obj, Register klass, Register var_size_in_bytes, int con_size_in_bytes, Register t1, Register t2) {
301 assert((con_size_in_bytes & MinObjAlignmentInBytesMask) == 0,
302 "con_size_in_bytes is not multiple of alignment");
303 const int hdr_size_in_bytes = instanceOopDesc::header_size() * HeapWordSize;
304
305 initialize_header(obj, klass, noreg, t1, t2);
306
307 // clear rest of allocated space
308 const Register index = t2;
309 const int threshold = 16 * BytesPerWord; // approximate break even point for code size (see comments below)
310 if (var_size_in_bytes != noreg) {
311 mov(index, var_size_in_bytes);
312 initialize_body(obj, index, hdr_size_in_bytes, t1);
313 } else if (con_size_in_bytes <= threshold) {
314 // use explicit null stores
315 int i = hdr_size_in_bytes;
316 if (i < con_size_in_bytes && (con_size_in_bytes % (2 * BytesPerWord))) {
317 str(zr, Address(obj, i));
318 i += BytesPerWord;
319 }
320 for (; i < con_size_in_bytes; i += 2 * BytesPerWord)
321 stp(zr, zr, Address(obj, i));
322 } else if (con_size_in_bytes > hdr_size_in_bytes) {
323 block_comment("zero memory");
324 // use loop to null out the fields
325
326 int words = (con_size_in_bytes - hdr_size_in_bytes) / BytesPerWord;
327 mov(index, words / 8);
328
329 const int unroll = 8; // Number of str(zr) instructions we'll unroll
330 int remainder = words % unroll;
331 lea(rscratch1, Address(obj, hdr_size_in_bytes + remainder * BytesPerWord));
332
333 Label entry_point, loop;
334 b(entry_point);
335
336 bind(loop);
337 sub(index, index, 1);
338 for (int i = -unroll; i < 0; i++) {
339 if (-i == remainder)
340 bind(entry_point);
341 str(zr, Address(rscratch1, i * wordSize));
342 }
343 if (remainder == 0)
344 bind(entry_point);
345 add(rscratch1, rscratch1, unroll * wordSize);
346 cbnz(index, loop);
347
348 }
349
350 membar(StoreStore);
351
352 if (CURRENT_ENV->dtrace_alloc_probes()) {
353 assert(obj == r0, "must be");
354 far_call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id)));
355 }
356
357 verify_oop(obj);
358 }
359 void C1_MacroAssembler::allocate_array(Register obj, Register len, Register t1, Register t2, int header_size, int f, Register klass, Label& slow_case) {
360 assert_different_registers(obj, len, t1, t2, klass);
361
362 // determine alignment mask
363 assert(!(BytesPerWord & 1), "must be a multiple of 2 for masking code to work");
364
365 // check for negative or excessive length
366 mov(rscratch1, (int32_t)max_array_allocation_length);
367 cmp(len, rscratch1);
368 br(Assembler::HS, slow_case);
369
370 const Register arr_size = t2; // okay to be the same
371 // align object end
372 mov(arr_size, (int32_t)header_size * BytesPerWord + MinObjAlignmentInBytesMask);
373 add(arr_size, arr_size, len, ext::uxtw, f);
374 andr(arr_size, arr_size, ~MinObjAlignmentInBytesMask);
375
376 try_allocate(obj, arr_size, 0, t1, t2, slow_case);
377
378 initialize_header(obj, klass, len, t1, t2);
379
380 // clear rest of allocated space
381 const Register len_zero = len;
382 initialize_body(obj, arr_size, header_size * BytesPerWord, len_zero);
383
384 membar(StoreStore);
385
386 if (CURRENT_ENV->dtrace_alloc_probes()) {
387 assert(obj == r0, "must be");
388 far_call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id)));
389 }
390
391 verify_oop(obj);
392 }
393
394
395 void C1_MacroAssembler::inline_cache_check(Register receiver, Register iCache) {
396 verify_oop(receiver);
397 // explicit NULL check not needed since load from [klass_offset] causes a trap
398 // check against inline cache
399 assert(!MacroAssembler::needs_explicit_null_check(oopDesc::klass_offset_in_bytes()), "must add explicit null check");
400
401 cmp_klass(receiver, iCache, rscratch1);
402 }
403
404
405 void C1_MacroAssembler::build_frame(int framesize, int bang_size_in_bytes) {
406 // If we have to make this method not-entrant we'll overwrite its
407 // first instruction with a jump. For this action to be legal we
408 // must ensure that this first instruction is a B, BL, NOP, BKPT,
409 // SVC, HVC, or SMC. Make it a NOP.
410 nop();
411 assert(bang_size_in_bytes >= framesize, "stack bang size incorrect");
412 // Make sure there is enough stack space for this method's activation.
413 // Note that we do this before doing an enter().
414 generate_stack_overflow_check(bang_size_in_bytes);
415 MacroAssembler::build_frame(framesize + 2 * wordSize);
416 }
417
418 void C1_MacroAssembler::remove_frame(int framesize) {
419 MacroAssembler::remove_frame(framesize + 2 * wordSize);
420 }
421
422
423 void C1_MacroAssembler::verified_entry() {
424 }
425
426 #ifndef PRODUCT
427
428 void C1_MacroAssembler::verify_stack_oop(int stack_offset) {
429 if (!VerifyOops) return;
430 verify_oop_addr(Address(sp, stack_offset), "oop");
431 }
432
433 void C1_MacroAssembler::verify_not_null_oop(Register r) {
434 if (!VerifyOops) return;
435 Label not_null;
436 cbnz(r, not_null);
437 stop("non-null oop required");
438 bind(not_null);
439 verify_oop(r);
440 }
441
442 void C1_MacroAssembler::invalidate_registers(bool inv_r0, bool inv_r19, bool inv_r2, bool inv_r3, bool inv_r4, bool inv_r5) {
443 #ifdef ASSERT
444 static int nn;
445 if (inv_r0) mov(r0, 0xDEAD);
446 if (inv_r19) mov(r19, 0xDEAD);
447 if (inv_r2) mov(r2, nn++);
448 if (inv_r3) mov(r3, 0xDEAD);
449 if (inv_r4) mov(r4, 0xDEAD);
450 if (inv_r5) mov(r5, 0xDEAD);
451 #endif
452 }
453 #endif // ifndef PRODUCT