1 /* 2 * Copyright (c) 1999, 2011, Oracle and/or its affiliates. All rights reserved. 3 * Copyright (c) 2014, Red Hat Inc. All rights reserved. 4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 5 * 6 * This code is free software; you can redistribute it and/or modify it 7 * under the terms of the GNU General Public License version 2 only, as 8 * published by the Free Software Foundation. 9 * 10 * This code is distributed in the hope that it will be useful, but WITHOUT 11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 13 * version 2 for more details (a copy is included in the LICENSE file that 14 * accompanied this code). 15 * 16 * You should have received a copy of the GNU General Public License version 17 * 2 along with this work; if not, write to the Free Software Foundation, 18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 19 * 20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 21 * or visit www.oracle.com if you need additional information or have any 22 * questions. 23 * 24 */ 25 26 #include "precompiled.hpp" 27 #include "c1/c1_MacroAssembler.hpp" 28 #include "c1/c1_Runtime1.hpp" 29 #include "classfile/systemDictionary.hpp" 30 #include "gc_interface/collectedHeap.hpp" 31 #include "interpreter/interpreter.hpp" 32 #include "oops/arrayOop.hpp" 33 #include "oops/markOop.hpp" 34 #include "runtime/basicLock.hpp" 35 #include "runtime/biasedLocking.hpp" 36 #include "runtime/os.hpp" 37 #include "runtime/sharedRuntime.hpp" 38 #include "runtime/stubRoutines.hpp" 39 40 void C1_MacroAssembler::float_cmp(bool is_float, int unordered_result, 41 FloatRegister f0, FloatRegister f1, 42 Register result) 43 { 44 Label done; 45 if (is_float) { 46 fcmps(f0, f1); 47 } else { 48 fcmpd(f0, f1); 49 } 50 if (unordered_result < 0) { 51 // we want -1 for unordered or less than, 0 for equal and 1 for 52 // greater than. 53 cset(result, NE); // Not equal or unordered 54 cneg(result, result, LT); // Less than or unordered 55 } else { 56 // we want -1 for less than, 0 for equal and 1 for unordered or 57 // greater than. 58 cset(result, NE); // Not equal or unordered 59 cneg(result, result, LO); // Less than 60 } 61 } 62 63 int C1_MacroAssembler::lock_object(Register hdr, Register obj, Register disp_hdr, Register scratch, Label& slow_case) { 64 const int aligned_mask = BytesPerWord -1; 65 const int hdr_offset = oopDesc::mark_offset_in_bytes(); 66 assert(hdr != obj && hdr != disp_hdr && obj != disp_hdr, "registers must be different"); 67 Label done, fail; 68 int null_check_offset = -1; 69 70 verify_oop(obj); 71 72 // save object being locked into the BasicObjectLock 73 str(obj, Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes())); 74 75 if (UseBiasedLocking) { 76 assert(scratch != noreg, "should have scratch register at this point"); 77 null_check_offset = biased_locking_enter(disp_hdr, obj, hdr, scratch, false, done, &slow_case); 78 } else { 79 null_check_offset = offset(); 80 } 81 82 // Load object header 83 ldr(hdr, Address(obj, hdr_offset)); 84 // and mark it as unlocked 85 orr(hdr, hdr, markOopDesc::unlocked_value); 86 // save unlocked object header into the displaced header location on the stack 87 str(hdr, Address(disp_hdr, 0)); 88 // test if object header is still the same (i.e. unlocked), and if so, store the 89 // displaced header address in the object header - if it is not the same, get the 90 // object header instead 91 lea(rscratch2, Address(obj, hdr_offset)); 92 cmpxchgptr(hdr, disp_hdr, rscratch2, rscratch1, done, /*fallthough*/NULL); 93 // if the object header was the same, we're done 94 // if the object header was not the same, it is now in the hdr register 95 // => test if it is a stack pointer into the same stack (recursive locking), i.e.: 96 // 97 // 1) (hdr & aligned_mask) == 0 98 // 2) sp <= hdr 99 // 3) hdr <= sp + page_size 100 // 101 // these 3 tests can be done by evaluating the following expression: 102 // 103 // (hdr - sp) & (aligned_mask - page_size) 104 // 105 // assuming both the stack pointer and page_size have their least 106 // significant 2 bits cleared and page_size is a power of 2 107 mov(rscratch1, sp); 108 sub(hdr, hdr, rscratch1); 109 ands(hdr, hdr, aligned_mask - os::vm_page_size()); 110 // for recursive locking, the result is zero => save it in the displaced header 111 // location (NULL in the displaced hdr location indicates recursive locking) 112 str(hdr, Address(disp_hdr, 0)); 113 // otherwise we don't care about the result and handle locking via runtime call 114 cbnz(hdr, slow_case); 115 // done 116 bind(done); 117 if (PrintBiasedLockingStatistics) { 118 lea(rscratch2, ExternalAddress((address)BiasedLocking::fast_path_entry_count_addr())); 119 addmw(Address(rscratch2, 0), 1, rscratch1); 120 } 121 return null_check_offset; 122 } 123 124 125 void C1_MacroAssembler::unlock_object(Register hdr, Register obj, Register disp_hdr, Label& slow_case) { 126 const int aligned_mask = BytesPerWord -1; 127 const int hdr_offset = oopDesc::mark_offset_in_bytes(); 128 assert(hdr != obj && hdr != disp_hdr && obj != disp_hdr, "registers must be different"); 129 Label done; 130 131 if (UseBiasedLocking) { 132 // load object 133 ldr(obj, Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes())); 134 biased_locking_exit(obj, hdr, done); 135 } 136 137 // load displaced header 138 ldr(hdr, Address(disp_hdr, 0)); 139 // if the loaded hdr is NULL we had recursive locking 140 // if we had recursive locking, we are done 141 cbz(hdr, done); 142 if (!UseBiasedLocking) { 143 // load object 144 ldr(obj, Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes())); 145 } 146 verify_oop(obj); 147 // test if object header is pointing to the displaced header, and if so, restore 148 // the displaced header in the object - if the object header is not pointing to 149 // the displaced header, get the object header instead 150 // if the object header was not pointing to the displaced header, 151 // we do unlocking via runtime call 152 if (hdr_offset) { 153 lea(rscratch1, Address(obj, hdr_offset)); 154 cmpxchgptr(disp_hdr, hdr, rscratch1, rscratch2, done, &slow_case); 155 } else { 156 cmpxchgptr(disp_hdr, hdr, obj, rscratch2, done, &slow_case); 157 } 158 // done 159 bind(done); 160 } 161 162 163 // Defines obj, preserves var_size_in_bytes 164 void C1_MacroAssembler::try_allocate(Register obj, Register var_size_in_bytes, int con_size_in_bytes, Register t1, Register t2, Label& slow_case) { 165 if (UseTLAB) { 166 tlab_allocate(obj, var_size_in_bytes, con_size_in_bytes, t1, t2, slow_case); 167 } else { 168 eden_allocate(obj, var_size_in_bytes, con_size_in_bytes, t1, slow_case); 169 incr_allocated_bytes(noreg, var_size_in_bytes, con_size_in_bytes, t1); 170 } 171 } 172 173 void C1_MacroAssembler::initialize_header(Register obj, Register klass, Register len, Register t1, Register t2) { 174 assert_different_registers(obj, klass, len); 175 if (UseBiasedLocking && !len->is_valid()) { 176 assert_different_registers(obj, klass, len, t1, t2); 177 ldr(t1, Address(klass, Klass::prototype_header_offset())); 178 } else { 179 // This assumes that all prototype bits fit in an int32_t 180 mov(t1, (int32_t)(intptr_t)markOopDesc::prototype()); 181 } 182 str(t1, Address(obj, oopDesc::mark_offset_in_bytes())); 183 184 if (UseCompressedClassPointers) { // Take care not to kill klass 185 encode_klass_not_null(t1, klass); 186 strw(t1, Address(obj, oopDesc::klass_offset_in_bytes())); 187 } else { 188 str(klass, Address(obj, oopDesc::klass_offset_in_bytes())); 189 } 190 191 if (len->is_valid()) { 192 strw(len, Address(obj, arrayOopDesc::length_offset_in_bytes())); 193 } else if (UseCompressedClassPointers) { 194 store_klass_gap(obj, zr); 195 } 196 } 197 198 // Zero words; len is in bytes 199 // Destroys all registers except addr 200 // len must be a nonzero multiple of wordSize 201 void C1_MacroAssembler::zero_memory(Register addr, Register len, Register t1) { 202 assert_different_registers(addr, len, t1, rscratch1, rscratch2); 203 204 #ifdef ASSERT 205 { Label L; 206 tst(len, BytesPerWord - 1); 207 br(Assembler::EQ, L); 208 stop("len is not a multiple of BytesPerWord"); 209 bind(L); 210 } 211 #endif 212 213 #ifndef PRODUCT 214 block_comment("zero memory"); 215 #endif 216 217 Label loop; 218 Label entry; 219 220 // Algorithm: 221 // 222 // scratch1 = cnt & 7; 223 // cnt -= scratch1; 224 // p += scratch1; 225 // switch (scratch1) { 226 // do { 227 // cnt -= 8; 228 // p[-8] = 0; 229 // case 7: 230 // p[-7] = 0; 231 // case 6: 232 // p[-6] = 0; 233 // // ... 234 // case 1: 235 // p[-1] = 0; 236 // case 0: 237 // p += 8; 238 // } while (cnt); 239 // } 240 241 const int unroll = 8; // Number of str(zr) instructions we'll unroll 242 243 lsr(len, len, LogBytesPerWord); 244 andr(rscratch1, len, unroll - 1); // tmp1 = cnt % unroll 245 sub(len, len, rscratch1); // cnt -= unroll 246 // t1 always points to the end of the region we're about to zero 247 add(t1, addr, rscratch1, Assembler::LSL, LogBytesPerWord); 248 adr(rscratch2, entry); 249 sub(rscratch2, rscratch2, rscratch1, Assembler::LSL, 2); 250 br(rscratch2); 251 bind(loop); 252 sub(len, len, unroll); 253 for (int i = -unroll; i < 0; i++) 254 str(zr, Address(t1, i * wordSize)); 255 bind(entry); 256 add(t1, t1, unroll * wordSize); 257 cbnz(len, loop); 258 } 259 260 // preserves obj, destroys len_in_bytes 261 void C1_MacroAssembler::initialize_body(Register obj, Register len_in_bytes, int hdr_size_in_bytes, Register t1) { 262 Label done; 263 assert(obj != len_in_bytes && obj != t1 && t1 != len_in_bytes, "registers must be different"); 264 assert((hdr_size_in_bytes & (BytesPerWord - 1)) == 0, "header size is not a multiple of BytesPerWord"); 265 Register index = len_in_bytes; 266 // index is positive and ptr sized 267 subs(index, index, hdr_size_in_bytes); 268 br(Assembler::EQ, done); 269 // note: for the remaining code to work, index must be a multiple of BytesPerWord 270 #ifdef ASSERT 271 { Label L; 272 tst(index, BytesPerWord - 1); 273 br(Assembler::EQ, L); 274 stop("index is not a multiple of BytesPerWord"); 275 bind(L); 276 } 277 #endif 278 279 // Preserve obj 280 if (hdr_size_in_bytes) 281 add(obj, obj, hdr_size_in_bytes); 282 zero_memory(obj, index, t1); 283 if (hdr_size_in_bytes) 284 sub(obj, obj, hdr_size_in_bytes); 285 286 // done 287 bind(done); 288 } 289 290 291 void C1_MacroAssembler::allocate_object(Register obj, Register t1, Register t2, int header_size, int object_size, Register klass, Label& slow_case) { 292 assert_different_registers(obj, t1, t2); // XXX really? 293 assert(header_size >= 0 && object_size >= header_size, "illegal sizes"); 294 295 try_allocate(obj, noreg, object_size * BytesPerWord, t1, t2, slow_case); 296 297 initialize_object(obj, klass, noreg, object_size * HeapWordSize, t1, t2); 298 } 299 300 void C1_MacroAssembler::initialize_object(Register obj, Register klass, Register var_size_in_bytes, int con_size_in_bytes, Register t1, Register t2) { 301 assert((con_size_in_bytes & MinObjAlignmentInBytesMask) == 0, 302 "con_size_in_bytes is not multiple of alignment"); 303 const int hdr_size_in_bytes = instanceOopDesc::header_size() * HeapWordSize; 304 305 initialize_header(obj, klass, noreg, t1, t2); 306 307 // clear rest of allocated space 308 const Register index = t2; 309 const int threshold = 16 * BytesPerWord; // approximate break even point for code size (see comments below) 310 if (var_size_in_bytes != noreg) { 311 mov(index, var_size_in_bytes); 312 initialize_body(obj, index, hdr_size_in_bytes, t1); 313 } else if (con_size_in_bytes <= threshold) { 314 // use explicit null stores 315 int i = hdr_size_in_bytes; 316 if (i < con_size_in_bytes && (con_size_in_bytes % (2 * BytesPerWord))) { 317 str(zr, Address(obj, i)); 318 i += BytesPerWord; 319 } 320 for (; i < con_size_in_bytes; i += 2 * BytesPerWord) 321 stp(zr, zr, Address(obj, i)); 322 } else if (con_size_in_bytes > hdr_size_in_bytes) { 323 block_comment("zero memory"); 324 // use loop to null out the fields 325 326 int words = (con_size_in_bytes - hdr_size_in_bytes) / BytesPerWord; 327 mov(index, words / 8); 328 329 const int unroll = 8; // Number of str(zr) instructions we'll unroll 330 int remainder = words % unroll; 331 lea(rscratch1, Address(obj, hdr_size_in_bytes + remainder * BytesPerWord)); 332 333 Label entry_point, loop; 334 b(entry_point); 335 336 bind(loop); 337 sub(index, index, 1); 338 for (int i = -unroll; i < 0; i++) { 339 if (-i == remainder) 340 bind(entry_point); 341 str(zr, Address(rscratch1, i * wordSize)); 342 } 343 if (remainder == 0) 344 bind(entry_point); 345 add(rscratch1, rscratch1, unroll * wordSize); 346 cbnz(index, loop); 347 348 } 349 350 membar(StoreStore); 351 352 if (CURRENT_ENV->dtrace_alloc_probes()) { 353 assert(obj == r0, "must be"); 354 far_call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id))); 355 } 356 357 verify_oop(obj); 358 } 359 void C1_MacroAssembler::allocate_array(Register obj, Register len, Register t1, Register t2, int header_size, int f, Register klass, Label& slow_case) { 360 assert_different_registers(obj, len, t1, t2, klass); 361 362 // determine alignment mask 363 assert(!(BytesPerWord & 1), "must be a multiple of 2 for masking code to work"); 364 365 // check for negative or excessive length 366 mov(rscratch1, (int32_t)max_array_allocation_length); 367 cmp(len, rscratch1); 368 br(Assembler::HS, slow_case); 369 370 const Register arr_size = t2; // okay to be the same 371 // align object end 372 mov(arr_size, (int32_t)header_size * BytesPerWord + MinObjAlignmentInBytesMask); 373 add(arr_size, arr_size, len, ext::uxtw, f); 374 andr(arr_size, arr_size, ~MinObjAlignmentInBytesMask); 375 376 try_allocate(obj, arr_size, 0, t1, t2, slow_case); 377 378 initialize_header(obj, klass, len, t1, t2); 379 380 // clear rest of allocated space 381 const Register len_zero = len; 382 initialize_body(obj, arr_size, header_size * BytesPerWord, len_zero); 383 384 membar(StoreStore); 385 386 if (CURRENT_ENV->dtrace_alloc_probes()) { 387 assert(obj == r0, "must be"); 388 far_call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id))); 389 } 390 391 verify_oop(obj); 392 } 393 394 395 void C1_MacroAssembler::inline_cache_check(Register receiver, Register iCache) { 396 verify_oop(receiver); 397 // explicit NULL check not needed since load from [klass_offset] causes a trap 398 // check against inline cache 399 assert(!MacroAssembler::needs_explicit_null_check(oopDesc::klass_offset_in_bytes()), "must add explicit null check"); 400 401 cmp_klass(receiver, iCache, rscratch1); 402 } 403 404 405 void C1_MacroAssembler::build_frame(int framesize, int bang_size_in_bytes) { 406 // If we have to make this method not-entrant we'll overwrite its 407 // first instruction with a jump. For this action to be legal we 408 // must ensure that this first instruction is a B, BL, NOP, BKPT, 409 // SVC, HVC, or SMC. Make it a NOP. 410 nop(); 411 assert(bang_size_in_bytes >= framesize, "stack bang size incorrect"); 412 // Make sure there is enough stack space for this method's activation. 413 // Note that we do this before doing an enter(). 414 generate_stack_overflow_check(bang_size_in_bytes); 415 MacroAssembler::build_frame(framesize + 2 * wordSize); 416 if (NotifySimulator) { 417 notify(Assembler::method_entry); 418 } 419 } 420 421 void C1_MacroAssembler::remove_frame(int framesize) { 422 MacroAssembler::remove_frame(framesize + 2 * wordSize); 423 if (NotifySimulator) { 424 notify(Assembler::method_reentry); 425 } 426 } 427 428 429 void C1_MacroAssembler::verified_entry() { 430 } 431 432 #ifndef PRODUCT 433 434 void C1_MacroAssembler::verify_stack_oop(int stack_offset) { 435 if (!VerifyOops) return; 436 verify_oop_addr(Address(sp, stack_offset), "oop"); 437 } 438 439 void C1_MacroAssembler::verify_not_null_oop(Register r) { 440 if (!VerifyOops) return; 441 Label not_null; 442 cbnz(r, not_null); 443 stop("non-null oop required"); 444 bind(not_null); 445 verify_oop(r); 446 } 447 448 void C1_MacroAssembler::invalidate_registers(bool inv_r0, bool inv_r19, bool inv_r2, bool inv_r3, bool inv_r4, bool inv_r5) { 449 #ifdef ASSERT 450 static int nn; 451 if (inv_r0) mov(r0, 0xDEAD); 452 if (inv_r19) mov(r19, 0xDEAD); 453 if (inv_r2) mov(r2, nn++); 454 if (inv_r3) mov(r3, 0xDEAD); 455 if (inv_r4) mov(r4, 0xDEAD); 456 if (inv_r5) mov(r5, 0xDEAD); 457 #endif 458 } 459 #endif // ifndef PRODUCT