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