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 "gc/shared/barrierSet.hpp"
32 #include "gc/shared/barrierSetAssembler.hpp"
33 #include "interpreter/interpreter.hpp"
34 #include "oops/arrayOop.hpp"
35 #include "oops/markOop.hpp"
36 #include "runtime/basicLock.hpp"
37 #include "runtime/biasedLocking.hpp"
38 #include "runtime/os.hpp"
39 #include "runtime/sharedRuntime.hpp"
40 #include "runtime/stubRoutines.hpp"
41
42 void C1_MacroAssembler::float_cmp(bool is_float, int unordered_result,
43 FloatRegister f0, FloatRegister f1,
44 Register result)
45 {
46 Label done;
47 if (is_float) {
48 fcmps(f0, f1);
49 } else {
50 fcmpd(f0, f1);
51 }
52 if (unordered_result < 0) {
53 // we want -1 for unordered or less than, 0 for equal and 1 for
54 // greater than.
55 cset(result, NE); // Not equal or unordered
56 cneg(result, result, LT); // Less than or unordered
57 } else {
58 // we want -1 for less than, 0 for equal and 1 for unordered or
59 // greater than.
60 cset(result, NE); // Not equal or unordered
61 cneg(result, result, LO); // Less than
62 }
63 }
64
65 int C1_MacroAssembler::lock_object(Register hdr, Register obj, Register disp_hdr, Register scratch, Label& slow_case) {
66 const int aligned_mask = BytesPerWord -1;
67 const int hdr_offset = oopDesc::mark_offset_in_bytes();
68 assert(hdr != obj && hdr != disp_hdr && obj != disp_hdr, "registers must be different");
69 Label done;
70 int null_check_offset = -1;
71
72 verify_oop(obj);
73
74 // save object being locked into the BasicObjectLock
75 str(obj, Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes()));
76
77 if (UseBiasedLocking) {
78 assert(scratch != noreg, "should have scratch register at this point");
79 null_check_offset = biased_locking_enter(disp_hdr, obj, hdr, scratch, false, done, &slow_case);
80 } else {
81 null_check_offset = offset();
82 }
83
84 // Load object header
85 ldr(hdr, Address(obj, hdr_offset));
86 // and mark it as unlocked
87 orr(hdr, hdr, markOopDesc::unlocked_value);
88
89 if (EnableValhalla && !UseBiasedLocking) {
90 // Mask always_locked bit such that we go to the slow path if object is a value type
91 andr(hdr, hdr, ~markOopDesc::biased_lock_bit_in_place);
92 }
93
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)markOopDesc::prototype());
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 void C1_MacroAssembler::initialize_body(Register obj, Register len_in_bytes, int hdr_size_in_bytes, Register t1) {
207 assert(hdr_size_in_bytes >= 0, "header size must be positive or 0");
208 Label done;
209
210 // len_in_bytes is positive and ptr sized
211 subs(len_in_bytes, len_in_bytes, hdr_size_in_bytes);
212 br(Assembler::EQ, done);
213
214 // Preserve obj
215 if (hdr_size_in_bytes)
216 add(obj, obj, hdr_size_in_bytes);
217 zero_memory(obj, len_in_bytes, t1);
218 if (hdr_size_in_bytes)
219 sub(obj, obj, hdr_size_in_bytes);
220
221 bind(done);
222 }
223
224
225 void C1_MacroAssembler::allocate_object(Register obj, Register t1, Register t2, int header_size, int object_size, Register klass, Label& slow_case) {
226 assert_different_registers(obj, t1, t2); // XXX really?
227 assert(header_size >= 0 && object_size >= header_size, "illegal sizes");
228
229 try_allocate(obj, noreg, object_size * BytesPerWord, t1, t2, slow_case);
230
231 initialize_object(obj, klass, noreg, object_size * HeapWordSize, t1, t2, UseTLAB);
232 }
233
234 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) {
235 assert((con_size_in_bytes & MinObjAlignmentInBytesMask) == 0,
236 "con_size_in_bytes is not multiple of alignment");
237 const int hdr_size_in_bytes = instanceOopDesc::header_size() * HeapWordSize;
238
239 initialize_header(obj, klass, noreg, t1, t2);
240
241 if (!(UseTLAB && ZeroTLAB && is_tlab_allocated)) {
242 // clear rest of allocated space
243 const Register index = t2;
244 const int threshold = 16 * BytesPerWord; // approximate break even point for code size (see comments below)
245 if (var_size_in_bytes != noreg) {
246 mov(index, var_size_in_bytes);
247 initialize_body(obj, index, hdr_size_in_bytes, t1);
248 } else if (con_size_in_bytes <= threshold) {
249 // use explicit null stores
250 int i = hdr_size_in_bytes;
251 if (i < con_size_in_bytes && (con_size_in_bytes % (2 * BytesPerWord))) {
252 str(zr, Address(obj, i));
253 i += BytesPerWord;
254 }
255 for (; i < con_size_in_bytes; i += 2 * BytesPerWord)
256 stp(zr, zr, Address(obj, i));
257 } else if (con_size_in_bytes > hdr_size_in_bytes) {
258 block_comment("zero memory");
259 // use loop to null out the fields
260
261 int words = (con_size_in_bytes - hdr_size_in_bytes) / BytesPerWord;
262 mov(index, words / 8);
263
264 const int unroll = 8; // Number of str(zr) instructions we'll unroll
265 int remainder = words % unroll;
266 lea(rscratch1, Address(obj, hdr_size_in_bytes + remainder * BytesPerWord));
267
268 Label entry_point, loop;
269 b(entry_point);
270
271 bind(loop);
272 sub(index, index, 1);
273 for (int i = -unroll; i < 0; i++) {
274 if (-i == remainder)
275 bind(entry_point);
276 str(zr, Address(rscratch1, i * wordSize));
277 }
278 if (remainder == 0)
279 bind(entry_point);
280 add(rscratch1, rscratch1, unroll * wordSize);
281 cbnz(index, loop);
282
283 }
284 }
285
286 membar(StoreStore);
287
288 if (CURRENT_ENV->dtrace_alloc_probes()) {
289 assert(obj == r0, "must be");
290 far_call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id)));
291 }
292
293 verify_oop(obj);
294 }
295 void C1_MacroAssembler::allocate_array(Register obj, Register len, Register t1, Register t2, int header_size, int f, Register klass, Label& slow_case) {
296 assert_different_registers(obj, len, t1, t2, klass);
297
298 // determine alignment mask
299 assert(!(BytesPerWord & 1), "must be a multiple of 2 for masking code to work");
300
301 // check for negative or excessive length
302 mov(rscratch1, (int32_t)max_array_allocation_length);
303 cmp(len, rscratch1);
304 br(Assembler::HS, slow_case);
305
306 const Register arr_size = t2; // okay to be the same
307 // align object end
308 mov(arr_size, (int32_t)header_size * BytesPerWord + MinObjAlignmentInBytesMask);
309 add(arr_size, arr_size, len, ext::uxtw, f);
310 andr(arr_size, arr_size, ~MinObjAlignmentInBytesMask);
311
312 try_allocate(obj, arr_size, 0, t1, t2, slow_case);
313
314 initialize_header(obj, klass, len, t1, t2);
315
316 // clear rest of allocated space
317 const Register len_zero = len;
318 initialize_body(obj, arr_size, header_size * BytesPerWord, len_zero);
319
320 membar(StoreStore);
321
322 if (CURRENT_ENV->dtrace_alloc_probes()) {
323 assert(obj == r0, "must be");
324 far_call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id)));
325 }
326
327 verify_oop(obj);
328 }
329
330
331 void C1_MacroAssembler::inline_cache_check(Register receiver, Register iCache) {
332 verify_oop(receiver);
333 // explicit NULL check not needed since load from [klass_offset] causes a trap
334 // check against inline cache
335 assert(!MacroAssembler::needs_explicit_null_check(oopDesc::klass_offset_in_bytes()), "must add explicit null check");
336
337 cmp_klass(receiver, iCache, rscratch1);
338 }
339
340
341 void C1_MacroAssembler::build_frame(int framesize, int bang_size_in_bytes, bool needs_stack_repair, Label* verified_value_entry_label) {
342
343
344 // If we have to make this method not-entrant we'll overwrite its
345 // first instruction with a jump. For this action to be legal we
346 // must ensure that this first instruction is a B, BL, NOP, BKPT,
347 // SVC, HVC, or SMC. Make it a NOP.
348 nop();
349 assert(bang_size_in_bytes >= framesize, "stack bang size incorrect");
350 // Make sure there is enough stack space for this method's activation.
351 // Note that we do this before doing an enter().
352 generate_stack_overflow_check(bang_size_in_bytes);
353
354 guarantee(needs_stack_repair == false, "Stack repair should not be true");
355 if (verified_value_entry_label != NULL) {
356 bind(*verified_value_entry_label);
357 }
358
359 MacroAssembler::build_frame(framesize + 2 * wordSize);
360 if (NotifySimulator) {
361 notify(Assembler::method_entry);
362 }
363 }
364
365 void C1_MacroAssembler::remove_frame(int framesize, bool needs_stack_repair) {
366
367 guarantee(needs_stack_repair == false, "Stack repair should not be true");
368
369 MacroAssembler::remove_frame(framesize + 2 * wordSize);
370 if (NotifySimulator) {
371 notify(Assembler::method_reentry);
372 }
373 }
374
375 void C1_MacroAssembler::verified_value_entry() {
376 if (C1Breakpoint || VerifyFPU || !UseStackBanging) {
377 // Verified Entry first instruction should be 5 bytes long for correct
378 // patching by patch_verified_entry().
379 //
380 // C1Breakpoint and VerifyFPU have one byte first instruction.
381 // Also first instruction will be one byte "push(rbp)" if stack banging
382 // code is not generated (see build_frame() above).
383 // For all these cases generate long instruction first.
384 nop();
385 }
386
387 // build frame
388 // DMS CHECK: is it nop?
389 // verify_FPU(0, "method_entry");
390
391 }
392
393 int C1_MacroAssembler::scalarized_entry(const CompiledEntrySignature *ces, int frame_size_in_bytes, int bang_size_in_bytes, Label& verified_value_entry_label, bool is_value_ro_entry) {
394 guarantee(false, "Support for ValueTypePassFieldsAsArgs and ValueTypeReturnedAsFields is not implemented");
395 return 0;
396 }
397
398
399 void C1_MacroAssembler::load_parameter(int offset_in_words, Register reg) {
400 // rbp, + 0: link
401 // + 1: return address
402 // + 2: argument with offset 0
403 // + 3: argument with offset 1
404 // + 4: ...
405
406 ldr(reg, Address(rfp, (offset_in_words + 2) * BytesPerWord));
407 }
408
409 #ifndef PRODUCT
410
411 void C1_MacroAssembler::verify_stack_oop(int stack_offset) {
412 if (!VerifyOops) return;
413 verify_oop_addr(Address(sp, stack_offset), "oop");
414 }
415
416 void C1_MacroAssembler::verify_not_null_oop(Register r) {
417 if (!VerifyOops) return;
418 Label not_null;
419 cbnz(r, not_null);
420 stop("non-null oop required");
421 bind(not_null);
422 verify_oop(r);
423 }
424
425 void C1_MacroAssembler::invalidate_registers(bool inv_r0, bool inv_r19, bool inv_r2, bool inv_r3, bool inv_r4, bool inv_r5) {
426 #ifdef ASSERT
427 static int nn;
428 if (inv_r0) mov(r0, 0xDEAD);
429 if (inv_r19) mov(r19, 0xDEAD);
430 if (inv_r2) mov(r2, nn++);
431 if (inv_r3) mov(r3, 0xDEAD);
432 if (inv_r4) mov(r4, 0xDEAD);
433 if (inv_r5) mov(r5, 0xDEAD);
434 #endif
435 }
436 #endif // ifndef PRODUCT