1 /*
2 * Copyright (c) 1999, 2018, 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 "classfile/systemDictionary.hpp"
29 #include "gc/shared/barrierSet.hpp"
30 #include "gc/shared/barrierSetAssembler.hpp"
31 #include "gc/shared/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/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, bool check_always_locked) {
42 const int aligned_mask = BytesPerWord -1;
43 const int hdr_offset = oopDesc::mark_offset_in_bytes();
44 assert(hdr == rax, "hdr must be rax, for the cmpxchg instruction");
45 assert(hdr != obj && hdr != disp_hdr && obj != disp_hdr, "registers must be different");
46 Label done;
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 if (UseBiasedLocking) {
55 assert(scratch != noreg, "should have scratch register at this point");
56 null_check_offset = biased_locking_enter(disp_hdr, obj, hdr, scratch, false, done, &slow_case);
57 } else {
58 null_check_offset = offset();
59 }
60
61 // Load object header
62 movptr(hdr, Address(obj, hdr_offset));
63 if (check_always_locked) {
64 testl(hdr, markOopDesc::always_locked_pattern);
65 jcc(Assembler::notZero, slow_case);
66 }
67 // and mark it as unlocked
68 orptr(hdr, markOopDesc::unlocked_value);
69 // save unlocked object header into the displaced header location on the stack
70 movptr(Address(disp_hdr, 0), hdr);
71 // test if object header is still the same (i.e. unlocked), and if so, store the
72 // displaced header address in the object header - if it is not the same, get the
73 // object header instead
74 MacroAssembler::lock(); // must be immediately before cmpxchg!
75 cmpxchgptr(disp_hdr, Address(obj, hdr_offset));
76 // if the object header was the same, we're done
77 if (PrintBiasedLockingStatistics) {
78 cond_inc32(Assembler::equal,
79 ExternalAddress((address)BiasedLocking::fast_path_entry_count_addr()));
80 }
81 jcc(Assembler::equal, done);
82 // if the object header was not the same, it is now in the hdr register
83 // => test if it is a stack pointer into the same stack (recursive locking), i.e.:
84 //
85 // 1) (hdr & aligned_mask) == 0
86 // 2) rsp <= hdr
87 // 3) hdr <= rsp + page_size
88 //
89 // these 3 tests can be done by evaluating the following expression:
90 //
91 // (hdr - rsp) & (aligned_mask - page_size)
92 //
93 // assuming both the stack pointer and page_size have their least
94 // significant 2 bits cleared and page_size is a power of 2
95 subptr(hdr, rsp);
96 andptr(hdr, aligned_mask - os::vm_page_size());
97 // for recursive locking, the result is zero => save it in the displaced header
98 // location (NULL in the displaced hdr location indicates recursive locking)
99 movptr(Address(disp_hdr, 0), hdr);
100 // otherwise we don't care about the result and handle locking via runtime call
101 jcc(Assembler::notZero, slow_case);
102 // done
103 bind(done);
104 return null_check_offset;
105 }
106
107
108 void C1_MacroAssembler::unlock_object(Register hdr, Register obj, Register disp_hdr, Label& slow_case) {
109 const int aligned_mask = BytesPerWord -1;
110 const int hdr_offset = oopDesc::mark_offset_in_bytes();
111 assert(disp_hdr == rax, "disp_hdr must be rax, for the cmpxchg instruction");
112 assert(hdr != obj && hdr != disp_hdr && obj != disp_hdr, "registers must be different");
113 Label done;
114
115 if (UseBiasedLocking) {
116 // load object
117 movptr(obj, Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes()));
118 biased_locking_exit(obj, hdr, done);
119 }
120
121 // load displaced header
122 movptr(hdr, Address(disp_hdr, 0));
123 // if the loaded hdr is NULL we had recursive locking
124 testptr(hdr, hdr);
125 // if we had recursive locking, we are done
126 jcc(Assembler::zero, done);
127 if (!UseBiasedLocking) {
128 // load object
129 movptr(obj, Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes()));
130 }
131 verify_oop(obj);
132 // test if object header is pointing to the displaced header, and if so, restore
133 // the displaced header in the object - if the object header is not pointing to
134 // the displaced header, get the object header instead
135 MacroAssembler::lock(); // must be immediately before cmpxchg!
136 cmpxchgptr(hdr, Address(obj, hdr_offset));
137 // if the object header was not pointing to the displaced header,
138 // we do unlocking via runtime call
139 jcc(Assembler::notEqual, slow_case);
140 // done
141 bind(done);
142 }
143
144
145 // Defines obj, preserves var_size_in_bytes
146 void C1_MacroAssembler::try_allocate(Register obj, Register var_size_in_bytes, int con_size_in_bytes, Register t1, Register t2, Label& slow_case) {
147 if (UseTLAB) {
148 tlab_allocate(noreg, obj, var_size_in_bytes, con_size_in_bytes, t1, t2, slow_case);
149 } else {
150 eden_allocate(noreg, obj, var_size_in_bytes, con_size_in_bytes, t1, slow_case);
151 }
152 }
153
154
155 void C1_MacroAssembler::initialize_header(Register obj, Register klass, Register len, Register t1, Register t2) {
156 assert_different_registers(obj, klass, len);
157 if (UseBiasedLocking && !len->is_valid()) {
158 assert_different_registers(obj, klass, len, t1, t2);
159 movptr(t1, Address(klass, Klass::prototype_header_offset()));
160 movptr(Address(obj, oopDesc::mark_offset_in_bytes()), t1);
161 } else {
162 // This assumes that all prototype bits fit in an int32_t
163 movptr(Address(obj, oopDesc::mark_offset_in_bytes ()), (int32_t)(intptr_t)markOopDesc::prototype());
164 }
165 #ifdef _LP64
166 if (UseCompressedClassPointers) { // Take care not to kill klass
167 movptr(t1, klass);
168 encode_klass_not_null(t1);
169 movl(Address(obj, oopDesc::klass_offset_in_bytes()), t1);
170 } else
171 #endif
172 {
173 movptr(Address(obj, oopDesc::klass_offset_in_bytes()), klass);
174 }
175
176 if (len->is_valid()) {
177 movl(Address(obj, arrayOopDesc::length_offset_in_bytes()), len);
178 }
179 #ifdef _LP64
180 else if (UseCompressedClassPointers) {
181 xorptr(t1, t1);
182 store_klass_gap(obj, t1);
183 }
184 #endif
185 }
186
187
188 // preserves obj, destroys len_in_bytes
189 void C1_MacroAssembler::initialize_body(Register obj, Register len_in_bytes, int hdr_size_in_bytes, Register t1) {
190 assert(hdr_size_in_bytes >= 0, "header size must be positive or 0");
191 Label done;
192
193 // len_in_bytes is positive and ptr sized
194 subptr(len_in_bytes, hdr_size_in_bytes);
195 jcc(Assembler::zero, done);
196 zero_memory(obj, len_in_bytes, hdr_size_in_bytes, t1);
197 bind(done);
198 }
199
200
201 void C1_MacroAssembler::allocate_object(Register obj, Register t1, Register t2, int header_size, int object_size, Register klass, Label& slow_case) {
202 assert(obj == rax, "obj must be in rax, for cmpxchg");
203 assert_different_registers(obj, t1, t2); // XXX really?
204 assert(header_size >= 0 && object_size >= header_size, "illegal sizes");
205
206 try_allocate(obj, noreg, object_size * BytesPerWord, t1, t2, slow_case);
207
208 initialize_object(obj, klass, noreg, object_size * HeapWordSize, t1, t2, UseTLAB);
209 }
210
211 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) {
212 assert((con_size_in_bytes & MinObjAlignmentInBytesMask) == 0,
213 "con_size_in_bytes is not multiple of alignment");
214 const int hdr_size_in_bytes = instanceOopDesc::header_size() * HeapWordSize;
215
216 initialize_header(obj, klass, noreg, t1, t2);
217
218 if (!(UseTLAB && ZeroTLAB && is_tlab_allocated)) {
219 // clear rest of allocated space
220 const Register t1_zero = t1;
221 const Register index = t2;
222 const int threshold = 6 * BytesPerWord; // approximate break even point for code size (see comments below)
223 if (var_size_in_bytes != noreg) {
224 mov(index, var_size_in_bytes);
225 initialize_body(obj, index, hdr_size_in_bytes, t1_zero);
226 } else if (con_size_in_bytes <= threshold) {
227 // use explicit null stores
228 // code size = 2 + 3*n bytes (n = number of fields to clear)
229 xorptr(t1_zero, t1_zero); // use t1_zero reg to clear memory (shorter code)
230 for (int i = hdr_size_in_bytes; i < con_size_in_bytes; i += BytesPerWord)
231 movptr(Address(obj, i), t1_zero);
232 } else if (con_size_in_bytes > hdr_size_in_bytes) {
233 // use loop to null out the fields
234 // code size = 16 bytes for even n (n = number of fields to clear)
235 // initialize last object field first if odd number of fields
236 xorptr(t1_zero, t1_zero); // use t1_zero reg to clear memory (shorter code)
237 movptr(index, (con_size_in_bytes - hdr_size_in_bytes) >> 3);
238 // initialize last object field if constant size is odd
239 if (((con_size_in_bytes - hdr_size_in_bytes) & 4) != 0)
240 movptr(Address(obj, con_size_in_bytes - (1*BytesPerWord)), t1_zero);
241 // initialize remaining object fields: rdx is a multiple of 2
242 { Label loop;
243 bind(loop);
244 movptr(Address(obj, index, Address::times_8, hdr_size_in_bytes - (1*BytesPerWord)),
245 t1_zero);
246 NOT_LP64(movptr(Address(obj, index, Address::times_8, hdr_size_in_bytes - (2*BytesPerWord)),
247 t1_zero);)
248 decrement(index);
249 jcc(Assembler::notZero, loop);
250 }
251 }
252 }
253
254 if (CURRENT_ENV->dtrace_alloc_probes()) {
255 assert(obj == rax, "must be");
256 call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id)));
257 }
258
259 verify_oop(obj);
260 }
261
262 void C1_MacroAssembler::allocate_array(Register obj, Register len, Register t1, Register t2, int header_size, Address::ScaleFactor f, Register klass, Label& slow_case) {
263 assert(obj == rax, "obj must be in rax, for cmpxchg");
264 assert_different_registers(obj, len, t1, t2, klass);
265
266 // determine alignment mask
267 assert(!(BytesPerWord & 1), "must be a multiple of 2 for masking code to work");
268
269 // check for negative or excessive length
270 cmpptr(len, (int32_t)max_array_allocation_length);
271 jcc(Assembler::above, slow_case);
272
273 const Register arr_size = t2; // okay to be the same
274 // align object end
275 movptr(arr_size, (int32_t)header_size * BytesPerWord + MinObjAlignmentInBytesMask);
276 lea(arr_size, Address(arr_size, len, f));
277 andptr(arr_size, ~MinObjAlignmentInBytesMask);
278
279 try_allocate(obj, arr_size, 0, t1, t2, slow_case);
280
281 initialize_header(obj, klass, len, t1, t2);
282
283 // clear rest of allocated space
284 const Register len_zero = len;
285 initialize_body(obj, arr_size, header_size * BytesPerWord, len_zero);
286
287 if (CURRENT_ENV->dtrace_alloc_probes()) {
288 assert(obj == rax, "must be");
289 call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id)));
290 }
291
292 verify_oop(obj);
293 }
294
295
296
297 void C1_MacroAssembler::inline_cache_check(Register receiver, Register iCache) {
298 verify_oop(receiver);
299 // explicit NULL check not needed since load from [klass_offset] causes a trap
300 // check against inline cache
301 assert(!MacroAssembler::needs_explicit_null_check(oopDesc::klass_offset_in_bytes()), "must add explicit null check");
302 int start_offset = offset();
303
304 if (UseCompressedClassPointers) {
305 load_klass(rscratch1, receiver);
306 cmpptr(rscratch1, iCache);
307 } else {
308 cmpptr(iCache, Address(receiver, oopDesc::klass_offset_in_bytes()));
309 }
310 // if icache check fails, then jump to runtime routine
311 // Note: RECEIVER must still contain the receiver!
312 jump_cc(Assembler::notEqual,
313 RuntimeAddress(SharedRuntime::get_ic_miss_stub()));
314 const int ic_cmp_size = LP64_ONLY(10) NOT_LP64(9);
315 assert(UseCompressedClassPointers || offset() - start_offset == ic_cmp_size, "check alignment in emit_method_entry");
316 }
317
318
319 void C1_MacroAssembler::build_frame(int frame_size_in_bytes, int bang_size_in_bytes) {
320 assert(bang_size_in_bytes >= frame_size_in_bytes, "stack bang size incorrect");
321 // Make sure there is enough stack space for this method's activation.
322 // Note that we do this before doing an enter(). This matches the
323 // ordering of C2's stack overflow check / rsp decrement and allows
324 // the SharedRuntime stack overflow handling to be consistent
325 // between the two compilers.
326 generate_stack_overflow_check(bang_size_in_bytes);
327
328 push(rbp);
329 if (PreserveFramePointer) {
330 mov(rbp, rsp);
331 }
332 #ifdef TIERED
333 // c2 leaves fpu stack dirty. Clean it on entry
334 if (UseSSE < 2 ) {
335 empty_FPU_stack();
336 }
337 #endif // TIERED
338 decrement(rsp, frame_size_in_bytes); // does not emit code for frame_size == 0
339
340 BarrierSetAssembler* bs = BarrierSet::barrier_set()->barrier_set_assembler();
341 bs->nmethod_entry_barrier(this);
342 }
343
344
345 void C1_MacroAssembler::remove_frame(int frame_size_in_bytes) {
346 increment(rsp, frame_size_in_bytes); // Does not emit code for frame_size == 0
347 pop(rbp);
348 }
349
350
351 void C1_MacroAssembler::verified_entry() {
352 if (C1Breakpoint || VerifyFPU || !UseStackBanging) {
353 // Verified Entry first instruction should be 5 bytes long for correct
354 // patching by patch_verified_entry().
355 //
356 // C1Breakpoint and VerifyFPU have one byte first instruction.
357 // Also first instruction will be one byte "push(rbp)" if stack banging
358 // code is not generated (see build_frame() above).
359 // For all these cases generate long instruction first.
360 fat_nop();
361 }
362 if (C1Breakpoint)int3();
363 // build frame
364 verify_FPU(0, "method_entry");
365 }
366
367 void C1_MacroAssembler::load_parameter(int offset_in_words, Register reg) {
368 // rbp, + 0: link
369 // + 1: return address
370 // + 2: argument with offset 0
371 // + 3: argument with offset 1
372 // + 4: ...
373
374 movptr(reg, Address(rbp, (offset_in_words + 2) * BytesPerWord));
375 }
376
377 #ifndef PRODUCT
378
379 void C1_MacroAssembler::verify_stack_oop(int stack_offset) {
380 if (!VerifyOops) return;
381 verify_oop_addr(Address(rsp, stack_offset));
382 }
383
384 void C1_MacroAssembler::verify_not_null_oop(Register r) {
385 if (!VerifyOops) return;
386 Label not_null;
387 testptr(r, r);
388 jcc(Assembler::notZero, not_null);
389 stop("non-null oop required");
390 bind(not_null);
391 verify_oop(r);
392 }
393
394 void C1_MacroAssembler::invalidate_registers(bool inv_rax, bool inv_rbx, bool inv_rcx, bool inv_rdx, bool inv_rsi, bool inv_rdi) {
395 #ifdef ASSERT
396 if (inv_rax) movptr(rax, 0xDEAD);
397 if (inv_rbx) movptr(rbx, 0xDEAD);
398 if (inv_rcx) movptr(rcx, 0xDEAD);
399 if (inv_rdx) movptr(rdx, 0xDEAD);
400 if (inv_rsi) movptr(rsi, 0xDEAD);
401 if (inv_rdi) movptr(rdi, 0xDEAD);
402 #endif
403 }
404
405 #endif // ifndef PRODUCT