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/sharedRuntime.hpp"
37 #include "runtime/stubRoutines.hpp"
38
39 int C1_MacroAssembler::lock_object(Register hdr, Register obj, Register disp_hdr, Register scratch, Label& slow_case) {
40 const int aligned_mask = BytesPerWord -1;
41 const int hdr_offset = oopDesc::mark_offset_in_bytes();
42 assert(hdr == rax, "hdr must be rax, for the cmpxchg instruction");
43 assert(hdr != obj && hdr != disp_hdr && obj != disp_hdr, "registers must be different");
44 Label done;
45 int null_check_offset = -1;
46
47 verify_oop(obj);
48
49 // save object being locked into the BasicObjectLock
50 movptr(Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes()), obj);
51
52 if (UseBiasedLocking) {
53 assert(scratch != noreg, "should have scratch register at this point");
54 null_check_offset = biased_locking_enter(disp_hdr, obj, hdr, scratch, false, done, &slow_case);
55 } else {
56 null_check_offset = offset();
57 }
58
59 // Load object header
60 movptr(hdr, Address(obj, hdr_offset));
61 // and mark it as unlocked
62 orptr(hdr, markOopDesc::unlocked_value);
63 // save unlocked object header into the displaced header location on the stack
64 movptr(Address(disp_hdr, 0), hdr);
65 // test if object header is still the same (i.e. unlocked), and if so, store the
66 // displaced header address in the object header - if it is not the same, get the
67 // object header instead
68 if (os::is_MP()) MacroAssembler::lock(); // must be immediately before cmpxchg!
69 cmpxchgptr(disp_hdr, Address(obj, hdr_offset));
70 // if the object header was the same, we're done
71 if (PrintBiasedLockingStatistics) {
72 cond_inc32(Assembler::equal,
73 ExternalAddress((address)BiasedLocking::fast_path_entry_count_addr()));
74 }
75 jcc(Assembler::equal, done);
76 // if the object header was not the same, it is now in the hdr register
77 // => test if it is a stack pointer into the same stack (recursive locking), i.e.:
78 //
79 // 1) (hdr & aligned_mask) == 0
80 // 2) rsp <= hdr
81 // 3) hdr <= rsp + page_size
82 //
83 // these 3 tests can be done by evaluating the following expression:
84 //
85 // (hdr - rsp) & (aligned_mask - page_size)
86 //
87 // assuming both the stack pointer and page_size have their least
88 // significant 2 bits cleared and page_size is a power of 2
89 subptr(hdr, rsp);
90 andptr(hdr, aligned_mask - os::vm_page_size());
91 // for recursive locking, the result is zero => save it in the displaced header
92 // location (NULL in the displaced hdr location indicates recursive locking)
93 movptr(Address(disp_hdr, 0), hdr);
94 // otherwise we don't care about the result and handle locking via runtime call
95 jcc(Assembler::notZero, slow_case);
96 // done
97 bind(done);
98 return null_check_offset;
99 }
100
101
102 void C1_MacroAssembler::unlock_object(Register hdr, Register obj, Register disp_hdr, Label& slow_case) {
103 const int aligned_mask = BytesPerWord -1;
104 const int hdr_offset = oopDesc::mark_offset_in_bytes();
105 assert(disp_hdr == rax, "disp_hdr must be rax, for the cmpxchg instruction");
106 assert(hdr != obj && hdr != disp_hdr && obj != disp_hdr, "registers must be different");
107 Label done;
108
109 if (UseBiasedLocking) {
110 // load object
111 movptr(obj, Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes()));
112 biased_locking_exit(obj, hdr, done);
113 }
114
115 // load displaced header
116 movptr(hdr, Address(disp_hdr, 0));
117 // if the loaded hdr is NULL we had recursive locking
118 testptr(hdr, hdr);
119 // if we had recursive locking, we are done
120 jcc(Assembler::zero, done);
121 if (!UseBiasedLocking) {
122 // load object
123 movptr(obj, Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes()));
124 }
125 verify_oop(obj);
126 // test if object header is pointing to the displaced header, and if so, restore
127 // the displaced header in the object - if the object header is not pointing to
128 // the displaced header, get the object header instead
129 if (os::is_MP()) MacroAssembler::lock(); // must be immediately before cmpxchg!
130 cmpxchgptr(hdr, Address(obj, hdr_offset));
131 // if the object header was not pointing to the displaced header,
132 // we do unlocking via runtime call
133 jcc(Assembler::notEqual, slow_case);
134 // done
135 bind(done);
136 }
137
138
139 // Defines obj, preserves var_size_in_bytes
140 void C1_MacroAssembler::try_allocate(Register obj, Register var_size_in_bytes, int con_size_in_bytes, Register t1, Register t2, Label& slow_case) {
141 if (UseTLAB) {
142 tlab_allocate(obj, var_size_in_bytes, con_size_in_bytes, t1, t2, slow_case);
143 } else {
144 eden_allocate(obj, var_size_in_bytes, con_size_in_bytes, t1, slow_case);
145 incr_allocated_bytes(noreg, var_size_in_bytes, con_size_in_bytes, t1);
146 }
147 }
148
149
150 void C1_MacroAssembler::initialize_header(Register obj, Register klass, Register len, Register t1, Register t2) {
151 assert_different_registers(obj, klass, len);
152 if (UseBiasedLocking && !len->is_valid()) {
153 assert_different_registers(obj, klass, len, t1, t2);
154 movptr(t1, Address(klass, Klass::prototype_header_offset()));
155 movptr(Address(obj, oopDesc::mark_offset_in_bytes()), t1);
156 } else {
157 // This assumes that all prototype bits fit in an int32_t
158 movptr(Address(obj, oopDesc::mark_offset_in_bytes ()), (int32_t)(intptr_t)markOopDesc::prototype());
159 }
160 #ifdef _LP64
161 if (UseCompressedClassPointers) { // Take care not to kill klass
162 movptr(t1, klass);
163 encode_klass_not_null(t1);
164 movl(Address(obj, oopDesc::klass_offset_in_bytes()), t1);
165 } else
166 #endif
167 {
168 movptr(Address(obj, oopDesc::klass_offset_in_bytes()), klass);
169 }
170
171 if (len->is_valid()) {
172 movl(Address(obj, arrayOopDesc::length_offset_in_bytes()), len);
173 }
174 #ifdef _LP64
175 else if (UseCompressedClassPointers) {
176 xorptr(t1, t1);
177 store_klass_gap(obj, t1);
178 }
179 #endif
180 }
181
182
183 // preserves obj, destroys len_in_bytes
184 void C1_MacroAssembler::initialize_body(Register obj, Register len_in_bytes, int hdr_size_in_bytes, Register t1) {
185 Label done;
186 assert(obj != len_in_bytes && obj != t1 && t1 != len_in_bytes, "registers must be different");
187 assert((hdr_size_in_bytes & (BytesPerWord - 1)) == 0, "header size is not a multiple of BytesPerWord");
188 Register index = len_in_bytes;
189 // index is positive and ptr sized
190 subptr(index, hdr_size_in_bytes);
191 jcc(Assembler::zero, done);
192 // initialize topmost word, divide index by 2, check if odd and test if zero
193 // note: for the remaining code to work, index must be a multiple of BytesPerWord
194 #ifdef ASSERT
195 { Label L;
196 testptr(index, BytesPerWord - 1);
197 jcc(Assembler::zero, L);
198 stop("index is not a multiple of BytesPerWord");
199 bind(L);
200 }
201 #endif
202 xorptr(t1, t1); // use _zero reg to clear memory (shorter code)
203 if (UseIncDec) {
204 shrptr(index, 3); // divide by 8/16 and set carry flag if bit 2 was set
205 } else {
206 shrptr(index, 2); // use 2 instructions to avoid partial flag stall
207 shrptr(index, 1);
208 }
209 #ifndef _LP64
210 // index could have been not a multiple of 8 (i.e., bit 2 was set)
211 { Label even;
212 // note: if index was a multiple of 8, than it cannot
213 // be 0 now otherwise it must have been 0 before
214 // => if it is even, we don't need to check for 0 again
215 jcc(Assembler::carryClear, even);
216 // clear topmost word (no jump needed if conditional assignment would work here)
217 movptr(Address(obj, index, Address::times_8, hdr_size_in_bytes - 0*BytesPerWord), t1);
218 // index could be 0 now, need to check again
219 jcc(Assembler::zero, done);
220 bind(even);
221 }
222 #endif // !_LP64
223 // initialize remaining object fields: rdx is a multiple of 2 now
224 { Label loop;
225 bind(loop);
226 movptr(Address(obj, index, Address::times_8, hdr_size_in_bytes - 1*BytesPerWord), t1);
227 NOT_LP64(movptr(Address(obj, index, Address::times_8, hdr_size_in_bytes - 2*BytesPerWord), t1);)
228 decrement(index);
229 jcc(Assembler::notZero, loop);
230 }
231
232 // done
233 bind(done);
234 }
235
236
237 void C1_MacroAssembler::allocate_object(Register obj, Register t1, Register t2, int header_size, int object_size, Register klass, Label& slow_case) {
238 assert(obj == rax, "obj must be in rax, for cmpxchg");
239 assert_different_registers(obj, t1, t2); // XXX really?
240 assert(header_size >= 0 && object_size >= header_size, "illegal sizes");
241
242 try_allocate(obj, noreg, object_size * BytesPerWord, t1, t2, slow_case);
243
244 initialize_object(obj, klass, noreg, object_size * HeapWordSize, t1, t2);
245 }
246
247 void C1_MacroAssembler::initialize_object(Register obj, Register klass, Register var_size_in_bytes, int con_size_in_bytes, Register t1, Register t2) {
248 assert((con_size_in_bytes & MinObjAlignmentInBytesMask) == 0,
249 "con_size_in_bytes is not multiple of alignment");
250 const int hdr_size_in_bytes = instanceOopDesc::header_size() * HeapWordSize;
251
252 initialize_header(obj, klass, noreg, t1, t2);
253
254 // clear rest of allocated space
255 const Register t1_zero = t1;
256 const Register index = t2;
257 const int threshold = 6 * BytesPerWord; // approximate break even point for code size (see comments below)
258 if (var_size_in_bytes != noreg) {
259 mov(index, var_size_in_bytes);
260 initialize_body(obj, index, hdr_size_in_bytes, t1_zero);
261 } else if (con_size_in_bytes <= threshold) {
262 // use explicit null stores
263 // code size = 2 + 3*n bytes (n = number of fields to clear)
264 xorptr(t1_zero, t1_zero); // use t1_zero reg to clear memory (shorter code)
265 for (int i = hdr_size_in_bytes; i < con_size_in_bytes; i += BytesPerWord)
266 movptr(Address(obj, i), t1_zero);
267 } else if (con_size_in_bytes > hdr_size_in_bytes) {
268 // use loop to null out the fields
269 // code size = 16 bytes for even n (n = number of fields to clear)
270 // initialize last object field first if odd number of fields
271 xorptr(t1_zero, t1_zero); // use t1_zero reg to clear memory (shorter code)
272 movptr(index, (con_size_in_bytes - hdr_size_in_bytes) >> 3);
273 // initialize last object field if constant size is odd
274 if (((con_size_in_bytes - hdr_size_in_bytes) & 4) != 0)
275 movptr(Address(obj, con_size_in_bytes - (1*BytesPerWord)), t1_zero);
276 // initialize remaining object fields: rdx is a multiple of 2
277 { Label loop;
278 bind(loop);
279 movptr(Address(obj, index, Address::times_8, hdr_size_in_bytes - (1*BytesPerWord)),
280 t1_zero);
281 NOT_LP64(movptr(Address(obj, index, Address::times_8, hdr_size_in_bytes - (2*BytesPerWord)),
282 t1_zero);)
283 decrement(index);
284 jcc(Assembler::notZero, loop);
285 }
286 }
287
288 if (CURRENT_ENV->dtrace_alloc_probes()) {
289 assert(obj == rax, "must be");
290 call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id)));
291 }
292
293 verify_oop(obj);
294 }
295
296 void C1_MacroAssembler::allocate_array(Register obj, Register len, Register t1, Register t2, int header_size, Address::ScaleFactor f, Register klass, Label& slow_case) {
297 assert(obj == rax, "obj must be in rax, for cmpxchg");
298 assert_different_registers(obj, len, t1, t2, klass);
299
300 // determine alignment mask
301 assert(!(BytesPerWord & 1), "must be a multiple of 2 for masking code to work");
302
303 // check for negative or excessive length
304 cmpptr(len, (int32_t)max_array_allocation_length);
305 jcc(Assembler::above, slow_case);
306
307 const Register arr_size = t2; // okay to be the same
308 // align object end
309 movptr(arr_size, (int32_t)header_size * BytesPerWord + MinObjAlignmentInBytesMask);
310 lea(arr_size, Address(arr_size, len, f));
311 andptr(arr_size, ~MinObjAlignmentInBytesMask);
312
313 try_allocate(obj, arr_size, 0, t1, t2, slow_case);
314
315 initialize_header(obj, klass, len, t1, t2);
316
317 // clear rest of allocated space
318 const Register len_zero = len;
319 initialize_body(obj, arr_size, header_size * BytesPerWord, len_zero);
320
321 if (CURRENT_ENV->dtrace_alloc_probes()) {
322 assert(obj == rax, "must be");
323 call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id)));
324 }
325
326 verify_oop(obj);
327 }
328
329
330
331 void C1_MacroAssembler::inline_cache_check(Register receiver, Register iCache) {
332 verify_oop(receiver);
333 // explicit NULL check not needed since load from [klass_offset] causes a trap
334 // check against inline cache
335 assert(!MacroAssembler::needs_explicit_null_check(oopDesc::klass_offset_in_bytes()), "must add explicit null check");
336 int start_offset = offset();
337
338 if (UseCompressedClassPointers) {
339 load_klass(rscratch1, receiver);
340 cmpptr(rscratch1, iCache);
341 } else {
342 cmpptr(iCache, Address(receiver, oopDesc::klass_offset_in_bytes()));
343 }
344 // if icache check fails, then jump to runtime routine
345 // Note: RECEIVER must still contain the receiver!
346 jump_cc(Assembler::notEqual,
347 RuntimeAddress(SharedRuntime::get_ic_miss_stub()));
348 const int ic_cmp_size = LP64_ONLY(10) NOT_LP64(9);
349 assert(UseCompressedClassPointers || offset() - start_offset == ic_cmp_size, "check alignment in emit_method_entry");
350 }
351
352
353 void C1_MacroAssembler::build_frame(int frame_size_in_bytes, int bang_size_in_bytes) {
354 assert(bang_size_in_bytes >= frame_size_in_bytes, "stack bang size incorrect");
355 // Make sure there is enough stack space for this method's activation.
356 // Note that we do this before doing an enter(). This matches the
357 // ordering of C2's stack overflow check / rsp decrement and allows
358 // the SharedRuntime stack overflow handling to be consistent
359 // between the two compilers.
360 generate_stack_overflow_check(bang_size_in_bytes);
361
362 push(rbp);
363 #ifdef TIERED
364 // c2 leaves fpu stack dirty. Clean it on entry
365 if (UseSSE < 2 ) {
366 empty_FPU_stack();
367 }
368 #endif // TIERED
369 decrement(rsp, frame_size_in_bytes); // does not emit code for frame_size == 0
370 }
371
372
373 void C1_MacroAssembler::remove_frame(int frame_size_in_bytes) {
374 increment(rsp, frame_size_in_bytes); // Does not emit code for frame_size == 0
375 pop(rbp);
376 }
377
378
379 void C1_MacroAssembler::unverified_entry(Register receiver, Register ic_klass) {
380 if (C1Breakpoint) int3();
381 inline_cache_check(receiver, ic_klass);
382 }
383
384
385 void C1_MacroAssembler::verified_entry() {
386 if (C1Breakpoint || VerifyFPU || !UseStackBanging) {
387 // Verified Entry first instruction should be 5 bytes long for correct
388 // patching by patch_verified_entry().
389 //
390 // C1Breakpoint and VerifyFPU have one byte first instruction.
391 // Also first instruction will be one byte "push(rbp)" if stack banging
392 // code is not generated (see build_frame() above).
393 // For all these cases generate long instruction first.
394 fat_nop();
395 }
396 if (C1Breakpoint)int3();
397 // build frame
398 verify_FPU(0, "method_entry");
399 }
400
401
402 #ifndef PRODUCT
403
404 void C1_MacroAssembler::verify_stack_oop(int stack_offset) {
405 if (!VerifyOops) return;
406 verify_oop_addr(Address(rsp, stack_offset));
407 }
408
409 void C1_MacroAssembler::verify_not_null_oop(Register r) {
410 if (!VerifyOops) return;
411 Label not_null;
412 testptr(r, r);
413 jcc(Assembler::notZero, not_null);
414 stop("non-null oop required");
415 bind(not_null);
416 verify_oop(r);
417 }
418
419 void C1_MacroAssembler::invalidate_registers(bool inv_rax, bool inv_rbx, bool inv_rcx, bool inv_rdx, bool inv_rsi, bool inv_rdi) {
420 #ifdef ASSERT
421 if (inv_rax) movptr(rax, 0xDEAD);
422 if (inv_rbx) movptr(rbx, 0xDEAD);
423 if (inv_rcx) movptr(rcx, 0xDEAD);
424 if (inv_rdx) movptr(rdx, 0xDEAD);
425 if (inv_rsi) movptr(rsi, 0xDEAD);
426 if (inv_rdi) movptr(rdi, 0xDEAD);
427 #endif
428 }
429
430 #endif // ifndef PRODUCT