1 /*
2 * Copyright (c) 1999, 2013, 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_interface/collectedHeap.hpp"
30 #include "interpreter/interpreter.hpp"
31 #include "oops/arrayOop.hpp"
32 #include "oops/markOop.hpp"
33 #include "runtime/basicLock.hpp"
34 #include "runtime/biasedLocking.hpp"
35 #include "runtime/os.hpp"
36 #include "runtime/stubRoutines.hpp"
37
38 int C1_MacroAssembler::lock_object(Register hdr, Register obj, Register disp_hdr, Register scratch, Label& slow_case) {
39 const int aligned_mask = BytesPerWord -1;
40 const int hdr_offset = oopDesc::mark_offset_in_bytes();
41 assert(hdr == rax, "hdr must be rax, for the cmpxchg instruction");
42 assert(hdr != obj && hdr != disp_hdr && obj != disp_hdr, "registers must be different");
43 Label done;
44 int null_check_offset = -1;
45
46 verify_oop(obj);
47
48 // save object being locked into the BasicObjectLock
49 movptr(Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes()), obj);
50
51 if (UseBiasedLocking) {
52 assert(scratch != noreg, "should have scratch register at this point");
53 null_check_offset = biased_locking_enter(disp_hdr, obj, hdr, scratch, false, done, &slow_case);
54 } else {
55 null_check_offset = offset();
56 }
57
58 // Load object header
59 movptr(hdr, Address(obj, hdr_offset));
60 // and mark it as unlocked
61 orptr(hdr, markOopDesc::unlocked_value);
62 // save unlocked object header into the displaced header location on the stack
63 movptr(Address(disp_hdr, 0), hdr);
64 // test if object header is still the same (i.e. unlocked), and if so, store the
65 // displaced header address in the object header - if it is not the same, get the
66 // object header instead
67 if (os::is_MP()) MacroAssembler::lock(); // must be immediately before cmpxchg!
68 cmpxchgptr(disp_hdr, Address(obj, hdr_offset));
69 // if the object header was the same, we're done
70 if (PrintBiasedLockingStatistics) {
71 cond_inc32(Assembler::equal,
72 ExternalAddress((address)BiasedLocking::fast_path_entry_count_addr()));
73 }
74 jcc(Assembler::equal, done);
75 // if the object header was not the same, it is now in the hdr register
76 // => test if it is a stack pointer into the same stack (recursive locking), i.e.:
77 //
78 // 1) (hdr & aligned_mask) == 0
79 // 2) rsp <= hdr
80 // 3) hdr <= rsp + page_size
81 //
82 // these 3 tests can be done by evaluating the following expression:
83 //
84 // (hdr - rsp) & (aligned_mask - page_size)
85 //
86 // assuming both the stack pointer and page_size have their least
87 // significant 2 bits cleared and page_size is a power of 2
88 subptr(hdr, rsp);
89 andptr(hdr, aligned_mask - os::vm_page_size());
90 // for recursive locking, the result is zero => save it in the displaced header
91 // location (NULL in the displaced hdr location indicates recursive locking)
92 movptr(Address(disp_hdr, 0), hdr);
93 // otherwise we don't care about the result and handle locking via runtime call
94 jcc(Assembler::notZero, slow_case);
95 // done
96 bind(done);
97 return null_check_offset;
98 }
99
100
101 void C1_MacroAssembler::unlock_object(Register hdr, Register obj, Register disp_hdr, Label& slow_case) {
102 const int aligned_mask = BytesPerWord -1;
103 const int hdr_offset = oopDesc::mark_offset_in_bytes();
104 assert(disp_hdr == rax, "disp_hdr must be rax, for the cmpxchg instruction");
105 assert(hdr != obj && hdr != disp_hdr && obj != disp_hdr, "registers must be different");
106 Label done;
107
108 if (UseBiasedLocking) {
109 // load object
110 movptr(obj, Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes()));
111 biased_locking_exit(obj, hdr, done);
112 }
113
114 // load displaced header
115 movptr(hdr, Address(disp_hdr, 0));
116 // if the loaded hdr is NULL we had recursive locking
117 testptr(hdr, hdr);
118 // if we had recursive locking, we are done
119 jcc(Assembler::zero, done);
120 if (!UseBiasedLocking) {
121 // load object
122 movptr(obj, Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes()));
123 }
124 verify_oop(obj);
125 // test if object header is pointing to the displaced header, and if so, restore
126 // the displaced header in the object - if the object header is not pointing to
127 // the displaced header, get the object header instead
128 if (os::is_MP()) MacroAssembler::lock(); // must be immediately before cmpxchg!
129 cmpxchgptr(hdr, Address(obj, hdr_offset));
130 // if the object header was not pointing to the displaced header,
131 // we do unlocking via runtime call
132 jcc(Assembler::notEqual, slow_case);
133 // done
134 bind(done);
135 }
136
137
138 // Defines obj, preserves var_size_in_bytes
139 void C1_MacroAssembler::try_allocate(Register obj, Register var_size_in_bytes, int con_size_in_bytes, Register t1, Register t2, Label& slow_case) {
140 if (UseTLAB) {
141 tlab_allocate(obj, var_size_in_bytes, con_size_in_bytes, t1, t2, slow_case);
142 } else {
143 eden_allocate(obj, var_size_in_bytes, con_size_in_bytes, t1, slow_case);
144 incr_allocated_bytes(noreg, var_size_in_bytes, con_size_in_bytes, t1);
145 }
146 }
147
148
149 void C1_MacroAssembler::initialize_header(Register obj, Register klass, Register len, Register t1, Register t2) {
150 assert_different_registers(obj, klass, len);
151 if (UseBiasedLocking && !len->is_valid()) {
152 assert_different_registers(obj, klass, len, t1, t2);
153 movptr(t1, Address(klass, Klass::prototype_header_offset()));
154 movptr(Address(obj, oopDesc::mark_offset_in_bytes()), t1);
155 } else {
156 // This assumes that all prototype bits fit in an int32_t
157 movptr(Address(obj, oopDesc::mark_offset_in_bytes ()), (int32_t)(intptr_t)markOopDesc::prototype());
158 }
159 #ifdef _LP64
160 if (UseCompressedClassPointers) { // Take care not to kill klass
161 movptr(t1, klass);
162 encode_klass_not_null(t1);
163 movl(Address(obj, oopDesc::klass_offset_in_bytes()), t1);
164 } else
165 #endif
166 {
167 movptr(Address(obj, oopDesc::klass_offset_in_bytes()), klass);
168 }
169
170 if (len->is_valid()) {
171 movl(Address(obj, arrayOopDesc::length_offset_in_bytes()), len);
172 }
173 #ifdef _LP64
174 else if (UseCompressedClassPointers) {
175 xorptr(t1, t1);
176 store_klass_gap(obj, t1);
177 }
178 #endif
179 }
180
181
182 // preserves obj, destroys len_in_bytes
183 void C1_MacroAssembler::initialize_body(Register obj, Register len_in_bytes, int hdr_size_in_bytes, Register t1) {
184 Label done;
185 assert(obj != len_in_bytes && obj != t1 && t1 != len_in_bytes, "registers must be different");
186 assert((hdr_size_in_bytes & (BytesPerWord - 1)) == 0, "header size is not a multiple of BytesPerWord");
187 Register index = len_in_bytes;
188 // index is positive and ptr sized
189 subptr(index, hdr_size_in_bytes);
190 jcc(Assembler::zero, done);
191 // initialize topmost word, divide index by 2, check if odd and test if zero
192 // note: for the remaining code to work, index must be a multiple of BytesPerWord
193 #ifdef ASSERT
194 { Label L;
195 testptr(index, BytesPerWord - 1);
196 jcc(Assembler::zero, L);
197 stop("index is not a multiple of BytesPerWord");
198 bind(L);
199 }
200 #endif
201 xorptr(t1, t1); // use _zero reg to clear memory (shorter code)
202 if (UseIncDec) {
203 shrptr(index, 3); // divide by 8/16 and set carry flag if bit 2 was set
204 } else {
205 shrptr(index, 2); // use 2 instructions to avoid partial flag stall
206 shrptr(index, 1);
207 }
208 #ifndef _LP64
209 // index could have been not a multiple of 8 (i.e., bit 2 was set)
210 { Label even;
211 // note: if index was a multiple of 8, than it cannot
212 // be 0 now otherwise it must have been 0 before
213 // => if it is even, we don't need to check for 0 again
214 jcc(Assembler::carryClear, even);
215 // clear topmost word (no jump needed if conditional assignment would work here)
216 movptr(Address(obj, index, Address::times_8, hdr_size_in_bytes - 0*BytesPerWord), t1);
217 // index could be 0 now, need to check again
218 jcc(Assembler::zero, done);
219 bind(even);
220 }
221 #endif // !_LP64
222 // initialize remaining object fields: rdx is a multiple of 2 now
223 { Label loop;
224 bind(loop);
225 movptr(Address(obj, index, Address::times_8, hdr_size_in_bytes - 1*BytesPerWord), t1);
226 NOT_LP64(movptr(Address(obj, index, Address::times_8, hdr_size_in_bytes - 2*BytesPerWord), t1);)
227 decrement(index);
228 jcc(Assembler::notZero, loop);
229 }
230
231 // done
232 bind(done);
233 }
234
235
236 void C1_MacroAssembler::allocate_object(Register obj, Register t1, Register t2, int header_size, int object_size, Register klass, Label& slow_case) {
237 assert(obj == rax, "obj must be in rax, for cmpxchg");
238 assert_different_registers(obj, t1, t2); // XXX really?
239 assert(header_size >= 0 && object_size >= header_size, "illegal sizes");
240
241 try_allocate(obj, noreg, object_size * BytesPerWord, t1, t2, slow_case);
242
243 initialize_object(obj, klass, noreg, object_size * HeapWordSize, t1, t2);
244 }
245
246 void C1_MacroAssembler::initialize_object(Register obj, Register klass, Register var_size_in_bytes, int con_size_in_bytes, Register t1, Register t2) {
247 assert((con_size_in_bytes & MinObjAlignmentInBytesMask) == 0,
248 "con_size_in_bytes is not multiple of alignment");
249 const int hdr_size_in_bytes = instanceOopDesc::header_size() * HeapWordSize;
250
251 initialize_header(obj, klass, noreg, t1, t2);
252
253 // clear rest of allocated space
254 const Register t1_zero = t1;
255 const Register index = t2;
256 const int threshold = 6 * BytesPerWord; // approximate break even point for code size (see comments below)
257 if (var_size_in_bytes != noreg) {
258 mov(index, var_size_in_bytes);
259 initialize_body(obj, index, hdr_size_in_bytes, t1_zero);
260 } else if (con_size_in_bytes <= threshold) {
261 // use explicit null stores
262 // code size = 2 + 3*n bytes (n = number of fields to clear)
263 xorptr(t1_zero, t1_zero); // use t1_zero reg to clear memory (shorter code)
264 for (int i = hdr_size_in_bytes; i < con_size_in_bytes; i += BytesPerWord)
265 movptr(Address(obj, i), t1_zero);
266 } else if (con_size_in_bytes > hdr_size_in_bytes) {
267 // use loop to null out the fields
268 // code size = 16 bytes for even n (n = number of fields to clear)
269 // initialize last object field first if odd number of fields
270 xorptr(t1_zero, t1_zero); // use t1_zero reg to clear memory (shorter code)
271 movptr(index, (con_size_in_bytes - hdr_size_in_bytes) >> 3);
272 // initialize last object field if constant size is odd
273 if (((con_size_in_bytes - hdr_size_in_bytes) & 4) != 0)
274 movptr(Address(obj, con_size_in_bytes - (1*BytesPerWord)), t1_zero);
275 // initialize remaining object fields: rdx is a multiple of 2
276 { Label loop;
277 bind(loop);
278 movptr(Address(obj, index, Address::times_8, hdr_size_in_bytes - (1*BytesPerWord)),
279 t1_zero);
280 NOT_LP64(movptr(Address(obj, index, Address::times_8, hdr_size_in_bytes - (2*BytesPerWord)),
281 t1_zero);)
282 decrement(index);
283 jcc(Assembler::notZero, loop);
284 }
285 }
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 void C1_MacroAssembler::allocate_array(Register obj, Register len, Register t1, Register t2, int header_size, Address::ScaleFactor f, Register klass, Label& slow_case) {
296 assert(obj == rax, "obj must be in rax, for cmpxchg");
297 assert_different_registers(obj, len, t1, t2, klass);
298
299 // determine alignment mask
300 assert(!(BytesPerWord & 1), "must be a multiple of 2 for masking code to work");
301
302 // check for negative or excessive length
303 cmpptr(len, (int32_t)max_array_allocation_length);
304 jcc(Assembler::above, slow_case);
305
306 const Register arr_size = t2; // okay to be the same
307 // align object end
308 movptr(arr_size, (int32_t)header_size * BytesPerWord + MinObjAlignmentInBytesMask);
309 lea(arr_size, Address(arr_size, len, f));
310 andptr(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 if (CURRENT_ENV->dtrace_alloc_probes()) {
321 assert(obj == rax, "must be");
322 call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id)));
323 }
324
325 verify_oop(obj);
326 }
327
328
329
330 void C1_MacroAssembler::inline_cache_check(Register receiver, Register iCache) {
331 verify_oop(receiver);
332 // explicit NULL check not needed since load from [klass_offset] causes a trap
333 // check against inline cache
334 assert(!MacroAssembler::needs_explicit_null_check(oopDesc::klass_offset_in_bytes()), "must add explicit null check");
335 int start_offset = offset();
336
337 if (UseCompressedClassPointers) {
338 load_klass(rscratch1, receiver);
339 cmpptr(rscratch1, iCache);
340 } else {
341 cmpptr(iCache, Address(receiver, oopDesc::klass_offset_in_bytes()));
342 }
343 // if icache check fails, then jump to runtime routine
344 // Note: RECEIVER must still contain the receiver!
345 jump_cc(Assembler::notEqual,
346 RuntimeAddress(SharedRuntime::get_ic_miss_stub()));
347 const int ic_cmp_size = LP64_ONLY(10) NOT_LP64(9);
348 assert(UseCompressedClassPointers || offset() - start_offset == ic_cmp_size, "check alignment in emit_method_entry");
349 }
350
351
352 void C1_MacroAssembler::build_frame(int frame_size_in_bytes) {
353 // Make sure there is enough stack space for this method's activation.
354 // Note that we do this before doing an enter(). This matches the
355 // ordering of C2's stack overflow check / rsp decrement and allows
356 // the SharedRuntime stack overflow handling to be consistent
357 // between the two compilers.
358 generate_stack_overflow_check(frame_size_in_bytes);
359
360 push(rbp);
361 #ifdef TIERED
362 // c2 leaves fpu stack dirty. Clean it on entry
363 if (UseSSE < 2 ) {
364 empty_FPU_stack();
365 }
366 #endif // TIERED
367 decrement(rsp, frame_size_in_bytes); // does not emit code for frame_size == 0
368 }
369
370
371 void C1_MacroAssembler::remove_frame(int frame_size_in_bytes) {
372 increment(rsp, frame_size_in_bytes); // Does not emit code for frame_size == 0
373 pop(rbp);
374 }
375
376
377 void C1_MacroAssembler::unverified_entry(Register receiver, Register ic_klass) {
378 if (C1Breakpoint) int3();
379 inline_cache_check(receiver, ic_klass);
380 }
381
382
383 void C1_MacroAssembler::verified_entry() {
384 if (C1Breakpoint || VerifyFPU || !UseStackBanging) {
385 // Verified Entry first instruction should be 5 bytes long for correct
386 // patching by patch_verified_entry().
387 //
388 // C1Breakpoint and VerifyFPU have one byte first instruction.
389 // Also first instruction will be one byte "push(rbp)" if stack banging
390 // code is not generated (see build_frame() above).
391 // For all these cases generate long instruction first.
392 fat_nop();
393 }
394 if (C1Breakpoint)int3();
395 // build frame
396 verify_FPU(0, "method_entry");
397 }
398
399
400 #ifndef PRODUCT
401
402 void C1_MacroAssembler::verify_stack_oop(int stack_offset) {
403 if (!VerifyOops) return;
404 verify_oop_addr(Address(rsp, stack_offset));
405 }
406
407 void C1_MacroAssembler::verify_not_null_oop(Register r) {
408 if (!VerifyOops) return;
409 Label not_null;
410 testptr(r, r);
411 jcc(Assembler::notZero, not_null);
412 stop("non-null oop required");
413 bind(not_null);
414 verify_oop(r);
415 }
416
417 void C1_MacroAssembler::invalidate_registers(bool inv_rax, bool inv_rbx, bool inv_rcx, bool inv_rdx, bool inv_rsi, bool inv_rdi) {
418 #ifdef ASSERT
419 if (inv_rax) movptr(rax, 0xDEAD);
420 if (inv_rbx) movptr(rbx, 0xDEAD);
421 if (inv_rcx) movptr(rcx, 0xDEAD);
422 if (inv_rdx) movptr(rdx, 0xDEAD);
423 if (inv_rsi) movptr(rsi, 0xDEAD);
424 if (inv_rdi) movptr(rdi, 0xDEAD);
425 #endif
426 }
427
428 #endif // ifndef PRODUCT