1 /*
2 * Copyright (c) 1999, 2021, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "c1/c1_MacroAssembler.hpp"
27 #include "c1/c1_Runtime1.hpp"
28 #include "gc/shared/barrierSet.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 int C1_MacroAssembler::lock_object(Register hdr, Register obj, Register disp_hdr, Register scratch, Label& slow_case) {
42 const Register rklass_decode_tmp = LP64_ONLY(rscratch1) NOT_LP64(noreg);
43 const int aligned_mask = BytesPerWord -1;
44 const int hdr_offset = oopDesc::mark_offset_in_bytes();
45 assert(hdr == rax, "hdr must be rax, for the cmpxchg instruction");
46 assert_different_registers(hdr, obj, disp_hdr, scratch);
47 int null_check_offset = -1;
48
49 verify_oop(obj);
50
51 // save object being locked into the BasicObjectLock
52 movptr(Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes()), obj);
53
54 null_check_offset = offset();
55
56 if (DiagnoseSyncOnValueBasedClasses != 0) {
57 load_klass(hdr, obj, rklass_decode_tmp);
58 movl(hdr, Address(hdr, Klass::access_flags_offset()));
59 testl(hdr, JVM_ACC_IS_VALUE_BASED_CLASS);
60 jcc(Assembler::notZero, slow_case);
61 }
62
63 if (LockingMode == LM_LIGHTWEIGHT) {
64 #ifdef _LP64
65 const Register thread = r15_thread;
66 #else
67 const Register thread = disp_hdr;
68 get_thread(thread);
69 #endif
70 // Load object header
71 movptr(hdr, Address(obj, hdr_offset));
72 fast_lock_impl(obj, hdr, thread, scratch, slow_case);
73 } else {
74 Label done;
75
76 if (UseBiasedLocking) {
77 assert(scratch != noreg, "should have scratch register at this point");
78 biased_locking_enter(disp_hdr, obj, hdr, scratch, rklass_decode_tmp, false, done, &slow_case);
79 }
80
81 // Load object header
82 movptr(hdr, Address(obj, hdr_offset));
83 // and mark it as unlocked
84 orptr(hdr, markWord::unlocked_value);
85 // save unlocked object header into the displaced header location on the stack
86 movptr(Address(disp_hdr, 0), hdr);
87 // test if object header is still the same (i.e. unlocked), and if so, store the
88 // displaced header address in the object header - if it is not the same, get the
89 // object header instead
90 MacroAssembler::lock(); // must be immediately before cmpxchg!
91 cmpxchgptr(disp_hdr, Address(obj, hdr_offset));
92 // if the object header was the same, we're done
93 if (PrintBiasedLockingStatistics) {
94 cond_inc32(Assembler::equal,
95 ExternalAddress((address)BiasedLocking::fast_path_entry_count_addr()));
96 }
97 jcc(Assembler::equal, done);
98 // if the object header was not the same, it is now in the hdr register
99 // => test if it is a stack pointer into the same stack (recursive locking), i.e.:
100 //
101 // 1) (hdr & aligned_mask) == 0
102 // 2) rsp <= hdr
103 // 3) hdr <= rsp + page_size
104 //
105 // these 3 tests can be done by evaluating the following expression:
106 //
107 // (hdr - rsp) & (aligned_mask - page_size)
108 //
109 // assuming both the stack pointer and page_size have their least
110 // significant 2 bits cleared and page_size is a power of 2
111 subptr(hdr, rsp);
112 andptr(hdr, aligned_mask - os::vm_page_size());
113 // for recursive locking, the result is zero => save it in the displaced header
114 // location (NULL in the displaced hdr location indicates recursive locking)
115 movptr(Address(disp_hdr, 0), hdr);
116 // otherwise we don't care about the result and handle locking via runtime call
117 jcc(Assembler::notZero, slow_case);
118 // done
119 bind(done);
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(disp_hdr == rax, "disp_hdr must be rax, for the cmpxchg instruction");
129 assert(hdr != obj && hdr != disp_hdr && obj != disp_hdr, "registers must be different");
130
131 if (LockingMode == LM_LIGHTWEIGHT) {
132 // load object
133 movptr(obj, Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes()));
134 verify_oop(obj);
135 movptr(disp_hdr, Address(obj, hdr_offset));
136 andptr(disp_hdr, ~(int32_t)markWord::lock_mask_in_place);
137 fast_unlock_impl(obj, disp_hdr, hdr, slow_case);
138 } else {
139 Label done;
140
141 if (UseBiasedLocking) {
142 // load object
143 movptr(obj, Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes()));
144 biased_locking_exit(obj, hdr, done);
145 }
146
147 // load displaced header
148 movptr(hdr, Address(disp_hdr, 0));
149 // if the loaded hdr is NULL we had recursive locking
150 testptr(hdr, hdr);
151 // if we had recursive locking, we are done
152 jcc(Assembler::zero, done);
153 if (!UseBiasedLocking) {
154 // load object
155 movptr(obj, Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes()));
156 }
157 verify_oop(obj);
158 // test if object header is pointing to the displaced header, and if so, restore
159 // the displaced header in the object - if the object header is not pointing to
160 // the displaced header, get the object header instead
161 MacroAssembler::lock(); // must be immediately before cmpxchg!
162 cmpxchgptr(hdr, Address(obj, hdr_offset));
163 // if the object header was not pointing to the displaced header,
164 // we do unlocking via runtime call
165 jcc(Assembler::notEqual, slow_case);
166 // done
167 bind(done);
168 }
169 }
170
171
172 // Defines obj, preserves var_size_in_bytes
173 void C1_MacroAssembler::try_allocate(Register obj, Register var_size_in_bytes, int con_size_in_bytes, Register t1, Register t2, Label& slow_case) {
174 if (UseTLAB) {
175 tlab_allocate(noreg, obj, var_size_in_bytes, con_size_in_bytes, t1, t2, slow_case);
176 } else {
177 eden_allocate(noreg, obj, var_size_in_bytes, con_size_in_bytes, t1, slow_case);
178 }
179 }
180
181
182 void C1_MacroAssembler::initialize_header(Register obj, Register klass, Register len, Register t1, Register t2) {
183 assert_different_registers(obj, klass, len, t1, t2);
184 if (UseCompactObjectHeaders || (UseBiasedLocking && !len->is_valid())) {
185 movptr(t1, Address(klass, Klass::prototype_header_offset()));
186 movptr(Address(obj, oopDesc::mark_offset_in_bytes()), t1);
187 } else {
188 movptr(Address(obj, oopDesc::mark_offset_in_bytes()), checked_cast<int32_t>(markWord::prototype().value()));
189 }
190
191 if (!UseCompactObjectHeaders) {
192 #ifdef _LP64
193 if (UseCompressedClassPointers) { // Take care not to kill klass
194 movptr(t1, klass);
195 encode_klass_not_null(t1, rscratch1);
196 movl(Address(obj, oopDesc::klass_offset_in_bytes()), t1);
197 } else
198 #endif
199 {
200 movptr(Address(obj, oopDesc::klass_offset_in_bytes()), klass);
201 }
202 }
203 if (len->is_valid()) {
204 movl(Address(obj, arrayOopDesc::length_offset_in_bytes()), len);
205 }
206 #ifdef _LP64
207 else if (UseCompressedClassPointers && !UseCompactObjectHeaders) {
208 xorptr(t1, t1);
209 store_klass_gap(obj, t1);
210 }
211 #endif
212 }
213
214
215 // preserves obj, destroys len_in_bytes
216 void C1_MacroAssembler::initialize_body(Register obj, Register len_in_bytes, int hdr_size_in_bytes, Register t1) {
217 assert(hdr_size_in_bytes >= 0, "header size must be positive or 0");
218 Label done;
219
220 // len_in_bytes is positive and ptr sized
221 subptr(len_in_bytes, hdr_size_in_bytes);
222 jcc(Assembler::zero, done);
223 zero_memory(obj, len_in_bytes, hdr_size_in_bytes, t1);
224 bind(done);
225 }
226
227
228 void C1_MacroAssembler::allocate_object(Register obj, Register t1, Register t2, int header_size, int object_size, Register klass, Label& slow_case) {
229 assert(obj == rax, "obj must be in rax, for cmpxchg");
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 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) {
239 assert((con_size_in_bytes & MinObjAlignmentInBytesMask) == 0,
240 "con_size_in_bytes is not multiple of alignment");
241 const int hdr_size_in_bytes = instanceOopDesc::header_size() * HeapWordSize;
242
243 initialize_header(obj, klass, noreg, t1, t2);
244
245 if (!(UseTLAB && ZeroTLAB && is_tlab_allocated)) {
246 // clear rest of allocated space
247 const Register t1_zero = t1;
248 const Register index = t2;
249 const int threshold = 6 * BytesPerWord; // approximate break even point for code size (see comments below)
250 int hdr_size_aligned = align_up(hdr_size_in_bytes, BytesPerWord); // klass gap is already cleared by init_header().
251 if (var_size_in_bytes != noreg) {
252 mov(index, var_size_in_bytes);
253 initialize_body(obj, index, hdr_size_aligned, t1_zero);
254 } else if (con_size_in_bytes <= threshold) {
255 // use explicit null stores
256 // code size = 2 + 3*n bytes (n = number of fields to clear)
257 xorptr(t1_zero, t1_zero); // use t1_zero reg to clear memory (shorter code)
258 for (int i = hdr_size_aligned; i < con_size_in_bytes; i += BytesPerWord)
259 movptr(Address(obj, i), t1_zero);
260 } else if (con_size_in_bytes > hdr_size_aligned) {
261 // use loop to null out the fields
262 // code size = 16 bytes for even n (n = number of fields to clear)
263 // initialize last object field first if odd number of fields
264 xorptr(t1_zero, t1_zero); // use t1_zero reg to clear memory (shorter code)
265 movptr(index, (con_size_in_bytes - hdr_size_in_bytes) >> 3);
266 // initialize last object field if constant size is odd
267 if (((con_size_in_bytes - hdr_size_aligned) & 4) != 0)
268 movptr(Address(obj, con_size_in_bytes - (1*BytesPerWord)), t1_zero);
269 // initialize remaining object fields: rdx is a multiple of 2
270 { Label loop;
271 bind(loop);
272 movptr(Address(obj, index, Address::times_8, hdr_size_aligned - (1*BytesPerWord)),
273 t1_zero);
274 NOT_LP64(movptr(Address(obj, index, Address::times_8, hdr_size_aligned - (2*BytesPerWord)),
275 t1_zero);)
276 decrement(index);
277 jcc(Assembler::notZero, loop);
278 }
279 }
280 }
281
282 if (CURRENT_ENV->dtrace_alloc_probes()) {
283 assert(obj == rax, "must be");
284 call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id)));
285 }
286
287 verify_oop(obj);
288 }
289
290 void C1_MacroAssembler::allocate_array(Register obj, Register len, Register t1, Register t2, int base_offset_in_bytes, Address::ScaleFactor f, Register klass, Label& slow_case) {
291 assert(obj == rax, "obj must be in rax, for cmpxchg");
292 assert_different_registers(obj, len, t1, t2, klass);
293
294 // determine alignment mask
295 assert(!(BytesPerWord & 1), "must be a multiple of 2 for masking code to work");
296
297 // check for negative or excessive length
298 cmpptr(len, (int32_t)max_array_allocation_length);
299 jcc(Assembler::above, slow_case);
300
301 const Register arr_size = t2; // okay to be the same
302 // align object end
303 movptr(arr_size, (int32_t)base_offset_in_bytes + MinObjAlignmentInBytesMask);
304 lea(arr_size, Address(arr_size, len, f));
305 andptr(arr_size, ~MinObjAlignmentInBytesMask);
306
307 try_allocate(obj, arr_size, 0, t1, t2, slow_case);
308
309 initialize_header(obj, klass, len, t1, t2);
310
311 // clear rest of allocated space
312 const Register len_zero = len;
313 initialize_body(obj, arr_size, base_offset_in_bytes, len_zero);
314
315 if (CURRENT_ENV->dtrace_alloc_probes()) {
316 assert(obj == rax, "must be");
317 call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id)));
318 }
319
320 verify_oop(obj);
321 }
322
323
324
325 void C1_MacroAssembler::inline_cache_check(Register receiver, Register iCache) {
326 verify_oop(receiver);
327 // explicit NULL check not needed since load from [klass_offset] causes a trap
328 // check against inline cache
329 assert(!MacroAssembler::needs_explicit_null_check(oopDesc::klass_offset_in_bytes()), "must add explicit null check");
330 int start_offset = offset();
331 Register tmp_load_klass = LP64_ONLY(rscratch2) NOT_LP64(noreg);
332
333 if (UseCompressedClassPointers) {
334 load_klass(rscratch1, receiver, tmp_load_klass);
335 cmpptr(rscratch1, iCache);
336 } else {
337 cmpptr(iCache, Address(receiver, oopDesc::klass_offset_in_bytes()));
338 }
339 // if icache check fails, then jump to runtime routine
340 // Note: RECEIVER must still contain the receiver!
341 jump_cc(Assembler::notEqual,
342 RuntimeAddress(SharedRuntime::get_ic_miss_stub()));
343 const int ic_cmp_size = LP64_ONLY(10) NOT_LP64(9);
344 assert(UseCompressedClassPointers || offset() - start_offset == ic_cmp_size, "check alignment in emit_method_entry");
345 }
346
347
348 void C1_MacroAssembler::build_frame(int frame_size_in_bytes, int bang_size_in_bytes) {
349 assert(bang_size_in_bytes >= frame_size_in_bytes, "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(). This matches the
352 // ordering of C2's stack overflow check / rsp decrement and allows
353 // the SharedRuntime stack overflow handling to be consistent
354 // between the two compilers.
355 generate_stack_overflow_check(bang_size_in_bytes);
356
357 push(rbp);
358 if (PreserveFramePointer) {
359 mov(rbp, rsp);
360 }
361 #if !defined(_LP64) && defined(COMPILER2)
362 if (UseSSE < 2 && !CompilerConfig::is_c1_only_no_jvmci()) {
363 // c2 leaves fpu stack dirty. Clean it on entry
364 empty_FPU_stack();
365 }
366 #endif // !_LP64 && COMPILER2
367 decrement(rsp, frame_size_in_bytes); // does not emit code for frame_size == 0
368
369 BarrierSetAssembler* bs = BarrierSet::barrier_set()->barrier_set_assembler();
370 bs->nmethod_entry_barrier(this);
371 }
372
373
374 void C1_MacroAssembler::remove_frame(int frame_size_in_bytes) {
375 increment(rsp, frame_size_in_bytes); // Does not emit code for frame_size == 0
376 pop(rbp);
377 }
378
379
380 void C1_MacroAssembler::verified_entry(bool breakAtEntry) {
381 if (breakAtEntry || VerifyFPU) {
382 // Verified Entry first instruction should be 5 bytes long for correct
383 // patching by patch_verified_entry().
384 //
385 // Breakpoint and VerifyFPU have one byte first instruction.
386 // Also first instruction will be one byte "push(rbp)" if stack banging
387 // code is not generated (see build_frame() above).
388 // For all these cases generate long instruction first.
389 fat_nop();
390 }
391 if (breakAtEntry) int3();
392 // build frame
393 IA32_ONLY( verify_FPU(0, "method_entry"); )
394 }
395
396 void C1_MacroAssembler::load_parameter(int offset_in_words, Register reg) {
397 // rbp, + 0: link
398 // + 1: return address
399 // + 2: argument with offset 0
400 // + 3: argument with offset 1
401 // + 4: ...
402
403 movptr(reg, Address(rbp, (offset_in_words + 2) * BytesPerWord));
404 }
405
406 #ifndef PRODUCT
407
408 void C1_MacroAssembler::verify_stack_oop(int stack_offset) {
409 if (!VerifyOops) return;
410 verify_oop_addr(Address(rsp, stack_offset));
411 }
412
413 void C1_MacroAssembler::verify_not_null_oop(Register r) {
414 if (!VerifyOops) return;
415 Label not_null;
416 testptr(r, r);
417 jcc(Assembler::notZero, not_null);
418 stop("non-null oop required");
419 bind(not_null);
420 verify_oop(r);
421 }
422
423 void C1_MacroAssembler::invalidate_registers(bool inv_rax, bool inv_rbx, bool inv_rcx, bool inv_rdx, bool inv_rsi, bool inv_rdi) {
424 #ifdef ASSERT
425 if (inv_rax) movptr(rax, 0xDEAD);
426 if (inv_rbx) movptr(rbx, 0xDEAD);
427 if (inv_rcx) movptr(rcx, 0xDEAD);
428 if (inv_rdx) movptr(rdx, 0xDEAD);
429 if (inv_rsi) movptr(rsi, 0xDEAD);
430 if (inv_rdi) movptr(rdi, 0xDEAD);
431 #endif
432 }
433
434 #endif // ifndef PRODUCT