1 /*
2 * Copyright 1999-2008 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any questions.
22 *
23 */
24
25 #include "incls/_precompiled.incl"
26 #include "incls/_c1_MacroAssembler_x86.cpp.incl"
27
28 int C1_MacroAssembler::lock_object(Register hdr, Register obj, Register disp_hdr, Register scratch, Label& slow_case) {
29 const int aligned_mask = BytesPerWord -1;
30 const int hdr_offset = oopDesc::mark_offset_in_bytes();
31 assert(hdr == rax, "hdr must be rax, for the cmpxchg instruction");
32 assert(hdr != obj && hdr != disp_hdr && obj != disp_hdr, "registers must be different");
33 Label done;
34 int null_check_offset = -1;
35
36 verify_oop(obj);
37
38 // save object being locked into the BasicObjectLock
39 movptr(Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes()), obj);
40
41 if (UseBiasedLocking) {
42 assert(scratch != noreg, "should have scratch register at this point");
43 null_check_offset = biased_locking_enter(disp_hdr, obj, hdr, scratch, false, done, &slow_case);
44 } else {
45 null_check_offset = offset();
46 }
47
48 // Load object header
49 movptr(hdr, Address(obj, hdr_offset));
50 // and mark it as unlocked
51 orptr(hdr, markOopDesc::unlocked_value);
52 // save unlocked object header into the displaced header location on the stack
53 movptr(Address(disp_hdr, 0), hdr);
54 // test if object header is still the same (i.e. unlocked), and if so, store the
55 // displaced header address in the object header - if it is not the same, get the
56 // object header instead
57 if (os::is_MP()) MacroAssembler::lock(); // must be immediately before cmpxchg!
58 cmpxchgptr(disp_hdr, Address(obj, hdr_offset));
59 // if the object header was the same, we're done
60 if (PrintBiasedLockingStatistics) {
61 cond_inc32(Assembler::equal,
62 ExternalAddress((address)BiasedLocking::fast_path_entry_count_addr()));
63 }
64 jcc(Assembler::equal, done);
65 // if the object header was not the same, it is now in the hdr register
66 // => test if it is a stack pointer into the same stack (recursive locking), i.e.:
67 //
68 // 1) (hdr & aligned_mask) == 0
69 // 2) rsp <= hdr
70 // 3) hdr <= rsp + page_size
71 //
72 // these 3 tests can be done by evaluating the following expression:
73 //
74 // (hdr - rsp) & (aligned_mask - page_size)
75 //
76 // assuming both the stack pointer and page_size have their least
77 // significant 2 bits cleared and page_size is a power of 2
78 subptr(hdr, rsp);
79 andptr(hdr, aligned_mask - os::vm_page_size());
80 // for recursive locking, the result is zero => save it in the displaced header
81 // location (NULL in the displaced hdr location indicates recursive locking)
82 movptr(Address(disp_hdr, 0), hdr);
83 // otherwise we don't care about the result and handle locking via runtime call
84 jcc(Assembler::notZero, slow_case);
85 // done
86 bind(done);
87 return null_check_offset;
88 }
89
90
91 void C1_MacroAssembler::unlock_object(Register hdr, Register obj, Register disp_hdr, Label& slow_case) {
92 const int aligned_mask = BytesPerWord -1;
93 const int hdr_offset = oopDesc::mark_offset_in_bytes();
94 assert(disp_hdr == rax, "disp_hdr must be rax, for the cmpxchg instruction");
95 assert(hdr != obj && hdr != disp_hdr && obj != disp_hdr, "registers must be different");
96 Label done;
97
98 if (UseBiasedLocking) {
99 // load object
100 movptr(obj, Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes()));
101 biased_locking_exit(obj, hdr, done);
102 }
103
104 // load displaced header
105 movptr(hdr, Address(disp_hdr, 0));
106 // if the loaded hdr is NULL we had recursive locking
107 testptr(hdr, hdr);
108 // if we had recursive locking, we are done
109 jcc(Assembler::zero, done);
110 if (!UseBiasedLocking) {
111 // load object
112 movptr(obj, Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes()));
113 }
114 verify_oop(obj);
115 // test if object header is pointing to the displaced header, and if so, restore
116 // the displaced header in the object - if the object header is not pointing to
117 // the displaced header, get the object header instead
118 if (os::is_MP()) MacroAssembler::lock(); // must be immediately before cmpxchg!
119 cmpxchgptr(hdr, Address(obj, hdr_offset));
120 // if the object header was not pointing to the displaced header,
121 // we do unlocking via runtime call
122 jcc(Assembler::notEqual, slow_case);
123 // done
124 bind(done);
125 }
126
127
128 // Defines obj, preserves var_size_in_bytes
129 void C1_MacroAssembler::try_allocate(Register obj, Register var_size_in_bytes, int con_size_in_bytes, Register t1, Register t2, Label& slow_case) {
130 if (UseTLAB) {
131 tlab_allocate(obj, var_size_in_bytes, con_size_in_bytes, t1, t2, slow_case);
132 } else {
133 eden_allocate(obj, var_size_in_bytes, con_size_in_bytes, t1, slow_case);
134 }
135 }
136
137
138 void C1_MacroAssembler::initialize_header(Register obj, Register klass, Register len, Register t1, Register t2) {
139 assert_different_registers(obj, klass, len);
140 if (UseBiasedLocking && !len->is_valid()) {
141 assert_different_registers(obj, klass, len, t1, t2);
142 movptr(t1, Address(klass, Klass::prototype_header_offset_in_bytes() + klassOopDesc::klass_part_offset_in_bytes()));
143 movptr(Address(obj, oopDesc::mark_offset_in_bytes()), t1);
144 } else {
145 // This assumes that all prototype bits fit in an int32_t
146 movptr(Address(obj, oopDesc::mark_offset_in_bytes ()), (int32_t)(intptr_t)markOopDesc::prototype());
147 }
148
149 movptr(Address(obj, oopDesc::klass_offset_in_bytes()), klass);
150 if (len->is_valid()) {
151 movl(Address(obj, arrayOopDesc::length_offset_in_bytes()), len);
152 }
153 }
154
155
156 // preserves obj, destroys len_in_bytes
157 void C1_MacroAssembler::initialize_body(Register obj, Register len_in_bytes, int hdr_size_in_bytes, Register t1) {
158 Label done;
159 assert(obj != len_in_bytes && obj != t1 && t1 != len_in_bytes, "registers must be different");
160 assert((hdr_size_in_bytes & (BytesPerWord - 1)) == 0, "header size is not a multiple of BytesPerWord");
161 Register index = len_in_bytes;
162 // index is positive and ptr sized
163 subptr(index, hdr_size_in_bytes);
164 jcc(Assembler::zero, done);
165 // initialize topmost word, divide index by 2, check if odd and test if zero
166 // note: for the remaining code to work, index must be a multiple of BytesPerWord
167 #ifdef ASSERT
168 { Label L;
169 testptr(index, BytesPerWord - 1);
170 jcc(Assembler::zero, L);
171 stop("index is not a multiple of BytesPerWord");
172 bind(L);
173 }
174 #endif
175 xorptr(t1, t1); // use _zero reg to clear memory (shorter code)
176 if (UseIncDec) {
177 shrptr(index, 3); // divide by 8/16 and set carry flag if bit 2 was set
178 } else {
179 shrptr(index, 2); // use 2 instructions to avoid partial flag stall
180 shrptr(index, 1);
181 }
182 #ifndef _LP64
183 // index could have been not a multiple of 8 (i.e., bit 2 was set)
184 { Label even;
185 // note: if index was a multiple of 8, than it cannot
186 // be 0 now otherwise it must have been 0 before
187 // => if it is even, we don't need to check for 0 again
188 jcc(Assembler::carryClear, even);
189 // clear topmost word (no jump needed if conditional assignment would work here)
190 movptr(Address(obj, index, Address::times_8, hdr_size_in_bytes - 0*BytesPerWord), t1);
191 // index could be 0 now, need to check again
192 jcc(Assembler::zero, done);
193 bind(even);
194 }
195 #endif // !_LP64
196 // initialize remaining object fields: rdx is a multiple of 2 now
197 { Label loop;
198 bind(loop);
199 movptr(Address(obj, index, Address::times_8, hdr_size_in_bytes - 1*BytesPerWord), t1);
200 NOT_LP64(movptr(Address(obj, index, Address::times_8, hdr_size_in_bytes - 2*BytesPerWord), t1);)
201 decrement(index);
202 jcc(Assembler::notZero, loop);
203 }
204
205 // done
206 bind(done);
207 }
208
209
210 void C1_MacroAssembler::allocate_object(Register obj, Register t1, Register t2, int header_size, int object_size, Register klass, Label& slow_case) {
211 assert(obj == rax, "obj must be in rax, for cmpxchg");
212 assert(obj != t1 && obj != t2 && t1 != t2, "registers must be different"); // XXX really?
213 assert(header_size >= 0 && object_size >= header_size, "illegal sizes");
214
215 try_allocate(obj, noreg, object_size * BytesPerWord, t1, t2, slow_case);
216
217 initialize_object(obj, klass, noreg, object_size * HeapWordSize, t1, t2);
218 }
219
220 void C1_MacroAssembler::initialize_object(Register obj, Register klass, Register var_size_in_bytes, int con_size_in_bytes, Register t1, Register t2) {
221 assert((con_size_in_bytes & MinObjAlignmentInBytesMask) == 0,
222 "con_size_in_bytes is not multiple of alignment");
223 const int hdr_size_in_bytes = instanceOopDesc::base_offset_in_bytes();
224
225 initialize_header(obj, klass, noreg, t1, t2);
226
227 // clear rest of allocated space
228 const Register t1_zero = t1;
229 const Register index = t2;
230 const int threshold = 6 * BytesPerWord; // approximate break even point for code size (see comments below)
231 if (var_size_in_bytes != noreg) {
232 mov(index, var_size_in_bytes);
233 initialize_body(obj, index, hdr_size_in_bytes, t1_zero);
234 } else if (con_size_in_bytes <= threshold) {
235 // use explicit null stores
236 // code size = 2 + 3*n bytes (n = number of fields to clear)
237 xorptr(t1_zero, t1_zero); // use t1_zero reg to clear memory (shorter code)
238 for (int i = hdr_size_in_bytes; i < con_size_in_bytes; i += BytesPerWord)
239 movptr(Address(obj, i), t1_zero);
240 } else if (con_size_in_bytes > hdr_size_in_bytes) {
241 // use loop to null out the fields
242 // code size = 16 bytes for even n (n = number of fields to clear)
243 // initialize last object field first if odd number of fields
244 xorptr(t1_zero, t1_zero); // use t1_zero reg to clear memory (shorter code)
245 movptr(index, (con_size_in_bytes - hdr_size_in_bytes) >> 3);
246 // initialize last object field if constant size is odd
247 if (((con_size_in_bytes - hdr_size_in_bytes) & 4) != 0)
248 movptr(Address(obj, con_size_in_bytes - (1*BytesPerWord)), t1_zero);
249 // initialize remaining object fields: rdx is a multiple of 2
250 { Label loop;
251 bind(loop);
252 movptr(Address(obj, index, Address::times_8, hdr_size_in_bytes - (1*BytesPerWord)),
253 t1_zero);
254 NOT_LP64(movptr(Address(obj, index, Address::times_8, hdr_size_in_bytes - (2*BytesPerWord)),
255 t1_zero);)
256 decrement(index);
257 jcc(Assembler::notZero, loop);
258 }
259 }
260
261 if (DTraceAllocProbes) {
262 assert(obj == rax, "must be");
263 call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id)));
264 }
265
266 verify_oop(obj);
267 }
268
269 void C1_MacroAssembler::allocate_array(Register obj, Register len, Register t1, Register t2, int header_size, Address::ScaleFactor f, Register klass, Label& slow_case) {
270 assert(obj == rax, "obj must be in rax, for cmpxchg");
271 assert_different_registers(obj, len, t1, t2, klass);
272
273 // determine alignment mask
274 assert(!(BytesPerWord & 1), "must be a multiple of 2 for masking code to work");
275
276 // check for negative or excessive length
277 cmpptr(len, (int32_t)max_array_allocation_length);
278 jcc(Assembler::above, slow_case);
279
280 const Register arr_size = t2; // okay to be the same
281 // align object end
282 movptr(arr_size, (int32_t)header_size * BytesPerWord + MinObjAlignmentInBytesMask);
283 lea(arr_size, Address(arr_size, len, f));
284 andptr(arr_size, ~MinObjAlignmentInBytesMask);
285
286 try_allocate(obj, arr_size, 0, t1, t2, slow_case);
287
288 initialize_header(obj, klass, len, t1, t2);
289
290 // clear rest of allocated space
291 const Register len_zero = len;
292 initialize_body(obj, arr_size, header_size * BytesPerWord, len_zero);
293
294 if (DTraceAllocProbes) {
295 assert(obj == rax, "must be");
296 call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id)));
297 }
298
299 verify_oop(obj);
300 }
301
302
303
304 void C1_MacroAssembler::inline_cache_check(Register receiver, Register iCache) {
305 verify_oop(receiver);
306 // explicit NULL check not needed since load from [klass_offset] causes a trap
307 // check against inline cache
308 assert(!MacroAssembler::needs_explicit_null_check(oopDesc::klass_offset_in_bytes()), "must add explicit null check");
309 int start_offset = offset();
310 cmpptr(iCache, Address(receiver, oopDesc::klass_offset_in_bytes()));
311 // if icache check fails, then jump to runtime routine
312 // Note: RECEIVER must still contain the receiver!
313 jump_cc(Assembler::notEqual,
314 RuntimeAddress(SharedRuntime::get_ic_miss_stub()));
315 const int ic_cmp_size = LP64_ONLY(10) NOT_LP64(9);
316 assert(offset() - start_offset == ic_cmp_size, "check alignment in emit_method_entry");
317 }
318
319
320 void C1_MacroAssembler::method_exit(bool restore_frame) {
321 if (restore_frame) {
322 leave();
323 }
324 ret(0);
325 }
326
327
328 void C1_MacroAssembler::build_frame(int frame_size_in_bytes) {
329 // Make sure there is enough stack space for this method's activation.
330 // Note that we do this before doing an enter(). This matches the
331 // ordering of C2's stack overflow check / rsp decrement and allows
332 // the SharedRuntime stack overflow handling to be consistent
333 // between the two compilers.
334 generate_stack_overflow_check(frame_size_in_bytes);
335
336 enter();
337 #ifdef TIERED
338 // c2 leaves fpu stack dirty. Clean it on entry
339 if (UseSSE < 2 ) {
340 empty_FPU_stack();
341 }
342 #endif // TIERED
343 decrement(rsp, frame_size_in_bytes); // does not emit code for frame_size == 0
344 }
345
346
347 void C1_MacroAssembler::unverified_entry(Register receiver, Register ic_klass) {
348 if (C1Breakpoint) int3();
349 inline_cache_check(receiver, ic_klass);
350 }
351
352
353 void C1_MacroAssembler::verified_entry() {
354 if (C1Breakpoint)int3();
355 // build frame
356 verify_FPU(0, "method_entry");
357 }
358
359
360 #ifndef PRODUCT
361
362 void C1_MacroAssembler::verify_stack_oop(int stack_offset) {
363 if (!VerifyOops) return;
364 verify_oop_addr(Address(rsp, stack_offset));
365 }
366
367 void C1_MacroAssembler::verify_not_null_oop(Register r) {
368 if (!VerifyOops) return;
369 Label not_null;
370 testptr(r, r);
371 jcc(Assembler::notZero, not_null);
372 stop("non-null oop required");
373 bind(not_null);
374 verify_oop(r);
375 }
376
377 void C1_MacroAssembler::invalidate_registers(bool inv_rax, bool inv_rbx, bool inv_rcx, bool inv_rdx, bool inv_rsi, bool inv_rdi) {
378 #ifdef ASSERT
379 if (inv_rax) movptr(rax, 0xDEAD);
380 if (inv_rbx) movptr(rbx, 0xDEAD);
381 if (inv_rcx) movptr(rcx, 0xDEAD);
382 if (inv_rdx) movptr(rdx, 0xDEAD);
383 if (inv_rsi) movptr(rsi, 0xDEAD);
384 if (inv_rdi) movptr(rdi, 0xDEAD);
385 #endif
386 }
387
388 #endif // ifndef PRODUCT