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 // 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 }
170 }
171
172 void C1_MacroAssembler::initialize_header(Register obj, Register klass, Register len, Register t1, Register t2) {
173 assert_different_registers(obj, klass, len);
174 if (UseBiasedLocking && !len->is_valid()) {
175 assert_different_registers(obj, klass, len, t1, t2);
176 ldr(t1, Address(klass, Klass::prototype_header_offset()));
177 } else {
178 // This assumes that all prototype bits fit in an int32_t
179 mov(t1, (int32_t)(intptr_t)markOopDesc::prototype());
180 }
181 str(t1, Address(obj, oopDesc::mark_offset_in_bytes()));
182
183 if (UseCompressedClassPointers) { // Take care not to kill klass
184 encode_klass_not_null(t1, klass);
185 strw(t1, Address(obj, oopDesc::klass_offset_in_bytes()));
186 } else {
187 str(klass, Address(obj, oopDesc::klass_offset_in_bytes()));
188 }
189
190 if (len->is_valid()) {
191 strw(len, Address(obj, arrayOopDesc::length_offset_in_bytes()));
192 } else if (UseCompressedClassPointers) {
193 store_klass_gap(obj, zr);
194 }
195 }
196
197 // preserves obj, destroys len_in_bytes
198 void C1_MacroAssembler::initialize_body(Register obj, Register len_in_bytes, int hdr_size_in_bytes, Register t1) {
199 assert(hdr_size_in_bytes >= 0, "header size must be positive or 0");
200 Label done;
201
202 // len_in_bytes is positive and ptr sized
203 subs(len_in_bytes, len_in_bytes, hdr_size_in_bytes);
204 br(Assembler::EQ, done);
205
206 // Preserve obj
207 if (hdr_size_in_bytes)
208 add(obj, obj, hdr_size_in_bytes);
209 zero_memory(obj, len_in_bytes, t1);
210 if (hdr_size_in_bytes)
211 sub(obj, obj, hdr_size_in_bytes);
212
213 bind(done);
214 }
215
216
217 void C1_MacroAssembler::allocate_object(Register obj, Register t1, Register t2, int header_size, int object_size, Register klass, Label& slow_case) {
218 assert_different_registers(obj, t1, t2); // XXX really?
219 assert(header_size >= 0 && object_size >= header_size, "illegal sizes");
220
221 try_allocate(obj, noreg, object_size * BytesPerWord, t1, t2, slow_case);
222
223 initialize_object(obj, klass, noreg, object_size * HeapWordSize, t1, t2, UseTLAB);
224 }
225
226 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) {
227 assert((con_size_in_bytes & MinObjAlignmentInBytesMask) == 0,
228 "con_size_in_bytes is not multiple of alignment");
229 const int hdr_size_in_bytes = instanceOopDesc::header_size() * HeapWordSize;
230
231 initialize_header(obj, klass, noreg, t1, t2);
232
233 if (!(UseTLAB && ZeroTLAB && is_tlab_allocated)) {
234 // clear rest of allocated space
235 const Register index = t2;
236 const int threshold = 16 * BytesPerWord; // approximate break even point for code size (see comments below)
237 if (var_size_in_bytes != noreg) {
238 mov(index, var_size_in_bytes);
239 initialize_body(obj, index, hdr_size_in_bytes, t1);
240 } else if (con_size_in_bytes <= threshold) {
241 // use explicit null stores
242 int i = hdr_size_in_bytes;
243 if (i < con_size_in_bytes && (con_size_in_bytes % (2 * BytesPerWord))) {
244 str(zr, Address(obj, i));
245 i += BytesPerWord;
246 }
247 for (; i < con_size_in_bytes; i += 2 * BytesPerWord)
248 stp(zr, zr, Address(obj, i));
249 } else if (con_size_in_bytes > hdr_size_in_bytes) {
250 block_comment("zero memory");
251 // use loop to null out the fields
252
253 int words = (con_size_in_bytes - hdr_size_in_bytes) / BytesPerWord;
254 mov(index, words / 8);
255
256 const int unroll = 8; // Number of str(zr) instructions we'll unroll
257 int remainder = words % unroll;
258 lea(rscratch1, Address(obj, hdr_size_in_bytes + remainder * BytesPerWord));
259
260 Label entry_point, loop;
261 b(entry_point);
262
263 bind(loop);
264 sub(index, index, 1);
265 for (int i = -unroll; i < 0; i++) {
266 if (-i == remainder)
267 bind(entry_point);
268 str(zr, Address(rscratch1, i * wordSize));
269 }
270 if (remainder == 0)
271 bind(entry_point);
272 add(rscratch1, rscratch1, unroll * wordSize);
273 cbnz(index, loop);
274
275 }
276 }
277
278 membar(StoreStore);
279
280 if (CURRENT_ENV->dtrace_alloc_probes()) {
281 assert(obj == r0, "must be");
282 far_call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id)));
283 }
284
285 verify_oop(obj);
286 }
287 void C1_MacroAssembler::allocate_array(Register obj, Register len, Register t1, Register t2, int header_size, int f, Register klass, Label& slow_case) {
288 assert_different_registers(obj, len, t1, t2, klass);
289
290 // determine alignment mask
291 assert(!(BytesPerWord & 1), "must be a multiple of 2 for masking code to work");
292
293 // check for negative or excessive length
294 mov(rscratch1, (int32_t)max_array_allocation_length);
295 cmp(len, rscratch1);
296 br(Assembler::HS, slow_case);
297
298 const Register arr_size = t2; // okay to be the same
299 // align object end
300 mov(arr_size, (int32_t)header_size * BytesPerWord + MinObjAlignmentInBytesMask);
301 add(arr_size, arr_size, len, ext::uxtw, f);
302 andr(arr_size, arr_size, ~MinObjAlignmentInBytesMask);
303
304 try_allocate(obj, arr_size, 0, t1, t2, slow_case);
305
306 initialize_header(obj, klass, len, t1, t2);
307
308 // clear rest of allocated space
309 const Register len_zero = len;
310 initialize_body(obj, arr_size, header_size * BytesPerWord, len_zero);
311
312 membar(StoreStore);
313
314 if (CURRENT_ENV->dtrace_alloc_probes()) {
315 assert(obj == r0, "must be");
316 far_call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id)));
317 }
318
319 verify_oop(obj);
320 }
321
322
323 void C1_MacroAssembler::inline_cache_check(Register receiver, Register iCache) {
324 verify_oop(receiver);
325 // explicit NULL check not needed since load from [klass_offset] causes a trap
326 // check against inline cache
327 assert(!MacroAssembler::needs_explicit_null_check(oopDesc::klass_offset_in_bytes()), "must add explicit null check");
328
329 cmp_klass(receiver, iCache, rscratch1);
330 }
331
332
333 void C1_MacroAssembler::build_frame(int framesize, int bang_size_in_bytes) {
334 // If we have to make this method not-entrant we'll overwrite its
335 // first instruction with a jump. For this action to be legal we
336 // must ensure that this first instruction is a B, BL, NOP, BKPT,
337 // SVC, HVC, or SMC. Make it a NOP.
338 nop();
339 assert(bang_size_in_bytes >= framesize, "stack bang size incorrect");
340 // Make sure there is enough stack space for this method's activation.
341 // Note that we do this before doing an enter().
342 generate_stack_overflow_check(bang_size_in_bytes);
343 MacroAssembler::build_frame(framesize + 2 * wordSize);
344 if (NotifySimulator) {
345 notify(Assembler::method_entry);
346 }
347 }
348
349 void C1_MacroAssembler::remove_frame(int framesize) {
350 MacroAssembler::remove_frame(framesize + 2 * wordSize);
351 if (NotifySimulator) {
352 notify(Assembler::method_reentry);
353 }
354 }
355
356
357 void C1_MacroAssembler::verified_entry() {
358 }
359
360 void C1_MacroAssembler::load_parameter(int offset_in_words, Register reg) {
361 // rbp, + 0: link
362 // + 1: return address
363 // + 2: argument with offset 0
364 // + 3: argument with offset 1
365 // + 4: ...
366
367 ldr(reg, Address(rfp, (offset_in_words + 2) * BytesPerWord));
368 }
369
370 #ifndef PRODUCT
371
372 void C1_MacroAssembler::verify_stack_oop(int stack_offset) {
373 if (!VerifyOops) return;
374 verify_oop_addr(Address(sp, stack_offset), "oop");
375 }
376
377 void C1_MacroAssembler::verify_not_null_oop(Register r) {
378 if (!VerifyOops) return;
379 Label not_null;
380 cbnz(r, not_null);
381 stop("non-null oop required");
382 bind(not_null);
383 verify_oop(r);
384 }
385
386 void C1_MacroAssembler::invalidate_registers(bool inv_r0, bool inv_r19, bool inv_r2, bool inv_r3, bool inv_r4, bool inv_r5) {
387 #ifdef ASSERT
388 static int nn;
389 if (inv_r0) mov(r0, 0xDEAD);
390 if (inv_r19) mov(r19, 0xDEAD);
391 if (inv_r2) mov(r2, nn++);
392 if (inv_r3) mov(r3, 0xDEAD);
393 if (inv_r4) mov(r4, 0xDEAD);
394 if (inv_r5) mov(r5, 0xDEAD);
395 #endif
396 }
397 #endif // ifndef PRODUCT