1 /* 2 * Copyright (c) 1999, 2021, Oracle and/or its affiliates. All rights reserved. 3 * Copyright (c) 2014, 2021, 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 "gc/shared/barrierSetAssembler.hpp" 30 #include "gc/shared/collectedHeap.hpp" 31 #include "gc/shared/tlab_globals.hpp" 32 #include "interpreter/interpreter.hpp" 33 #include "oops/arrayOop.hpp" 34 #include "oops/markWord.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 void C1_MacroAssembler::float_cmp(bool is_float, int unordered_result, 42 FloatRegister f0, FloatRegister f1, 43 Register result) 44 { 45 Label done; 46 if (is_float) { 47 fcmps(f0, f1); 48 } else { 49 fcmpd(f0, f1); 50 } 51 if (unordered_result < 0) { 52 // we want -1 for unordered or less than, 0 for equal and 1 for 53 // greater than. 54 cset(result, NE); // Not equal or unordered 55 cneg(result, result, LT); // Less than or unordered 56 } else { 57 // we want -1 for less than, 0 for equal and 1 for unordered or 58 // greater than. 59 cset(result, NE); // Not equal or unordered 60 cneg(result, result, LO); // Less than 61 } 62 } 63 64 int C1_MacroAssembler::lock_object(Register hdr, Register obj, Register disp_hdr, Register scratch, Label& slow_case) { 65 const int aligned_mask = BytesPerWord -1; 66 const int hdr_offset = oopDesc::mark_offset_in_bytes(); 67 assert(hdr != obj && hdr != disp_hdr && obj != disp_hdr, "registers must be different"); 68 Label done; 69 int null_check_offset = -1; 70 71 verify_oop(obj); 72 73 // save object being locked into the BasicObjectLock 74 str(obj, Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes())); 75 76 null_check_offset = offset(); 77 78 if (DiagnoseSyncOnValueBasedClasses != 0) { 79 load_klass(hdr, obj); 80 ldrw(hdr, Address(hdr, Klass::access_flags_offset())); 81 tstw(hdr, JVM_ACC_IS_VALUE_BASED_CLASS); 82 br(Assembler::NE, slow_case); 83 } 84 85 if (UseBiasedLocking) { 86 assert(scratch != noreg, "should have scratch register at this point"); 87 biased_locking_enter(disp_hdr, obj, hdr, scratch, false, done, &slow_case); 88 } 89 90 // Load object header 91 ldr(hdr, Address(obj, hdr_offset)); 92 if (LockingMode == LM_LIGHTWEIGHT) { 93 fast_lock(obj, hdr, rscratch1, rscratch2, slow_case); 94 } else { 95 // and mark it as unlocked 96 orr(hdr, hdr, markWord::unlocked_value); 97 // save unlocked object header into the displaced header location on the stack 98 str(hdr, Address(disp_hdr, 0)); 99 // test if object header is still the same (i.e. unlocked), and if so, store the 100 // displaced header address in the object header - if it is not the same, get the 101 // object header instead 102 lea(rscratch2, Address(obj, hdr_offset)); 103 cmpxchgptr(hdr, disp_hdr, rscratch2, rscratch1, done, /*fallthough*/NULL); 104 // if the object header was the same, we're done 105 // if the object header was not the same, it is now in the hdr register 106 // => test if it is a stack pointer into the same stack (recursive locking), i.e.: 107 // 108 // 1) (hdr & aligned_mask) == 0 109 // 2) sp <= hdr 110 // 3) hdr <= sp + page_size 111 // 112 // these 3 tests can be done by evaluating the following expression: 113 // 114 // (hdr - sp) & (aligned_mask - page_size) 115 // 116 // assuming both the stack pointer and page_size have their least 117 // significant 2 bits cleared and page_size is a power of 2 118 mov(rscratch1, sp); 119 sub(hdr, hdr, rscratch1); 120 ands(hdr, hdr, aligned_mask - os::vm_page_size()); 121 // for recursive locking, the result is zero => save it in the displaced header 122 // location (NULL in the displaced hdr location indicates recursive locking) 123 str(hdr, Address(disp_hdr, 0)); 124 // otherwise we don't care about the result and handle locking via runtime call 125 cbnz(hdr, slow_case); 126 // done 127 bind(done); 128 } 129 if (PrintBiasedLockingStatistics) { 130 lea(rscratch2, ExternalAddress((address)BiasedLocking::fast_path_entry_count_addr())); 131 addmw(Address(rscratch2, 0), 1, rscratch1); 132 } 133 return null_check_offset; 134 } 135 136 137 void C1_MacroAssembler::unlock_object(Register hdr, Register obj, Register disp_hdr, Label& slow_case) { 138 const int aligned_mask = BytesPerWord -1; 139 const int hdr_offset = oopDesc::mark_offset_in_bytes(); 140 assert(hdr != obj && hdr != disp_hdr && obj != disp_hdr, "registers must be different"); 141 Label done; 142 143 if (UseBiasedLocking) { 144 // load object 145 ldr(obj, Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes())); 146 biased_locking_exit(obj, hdr, done); 147 } 148 149 if (LockingMode != LM_LIGHTWEIGHT) { 150 // load displaced header 151 ldr(hdr, Address(disp_hdr, 0)); 152 // if the loaded hdr is null we had recursive locking 153 // if we had recursive locking, we are done 154 cbz(hdr, done); 155 } 156 157 if (!UseBiasedLocking) { 158 // load object 159 ldr(obj, Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes())); 160 } 161 verify_oop(obj); 162 163 if (LockingMode == LM_LIGHTWEIGHT) { 164 ldr(hdr, Address(obj, oopDesc::mark_offset_in_bytes())); 165 // We cannot use tbnz here, the target might be too far away and cannot 166 // be encoded. 167 tst(hdr, markWord::monitor_value); 168 br(Assembler::NE, slow_case); 169 fast_unlock(obj, hdr, rscratch1, rscratch2, slow_case); 170 } else { 171 // test if object header is pointing to the displaced header, and if so, restore 172 // the displaced header in the object - if the object header is not pointing to 173 // the displaced header, get the object header instead 174 // if the object header was not pointing to the displaced header, 175 // we do unlocking via runtime call 176 if (hdr_offset) { 177 lea(rscratch1, Address(obj, hdr_offset)); 178 cmpxchgptr(disp_hdr, hdr, rscratch1, rscratch2, done, &slow_case); 179 } else { 180 cmpxchgptr(disp_hdr, hdr, obj, rscratch2, done, &slow_case); 181 } 182 // done 183 bind(done); 184 } 185 } 186 187 188 // Defines obj, preserves var_size_in_bytes 189 void C1_MacroAssembler::try_allocate(Register obj, Register var_size_in_bytes, int con_size_in_bytes, Register t1, Register t2, Label& slow_case) { 190 if (UseTLAB) { 191 tlab_allocate(obj, var_size_in_bytes, con_size_in_bytes, t1, t2, slow_case); 192 } else { 193 eden_allocate(obj, var_size_in_bytes, con_size_in_bytes, t1, slow_case); 194 } 195 } 196 197 void C1_MacroAssembler::initialize_header(Register obj, Register klass, Register len, Register t1, Register t2) { 198 assert_different_registers(obj, klass, len); 199 if (UseCompactObjectHeaders || (UseBiasedLocking && !len->is_valid())) { 200 assert_different_registers(obj, klass, len, t1, t2); 201 ldr(t1, Address(klass, Klass::prototype_header_offset())); 202 } else { 203 // This assumes that all prototype bits fit in an int32_t 204 mov(t1, (int32_t)(intptr_t)markWord::prototype().value()); 205 } 206 str(t1, Address(obj, oopDesc::mark_offset_in_bytes())); 207 208 if (!UseCompactObjectHeaders) { 209 if (UseCompressedClassPointers) { // Take care not to kill klass 210 encode_klass_not_null(t1, klass); 211 strw(t1, Address(obj, oopDesc::klass_offset_in_bytes())); 212 } else { 213 str(klass, Address(obj, oopDesc::klass_offset_in_bytes())); 214 } 215 } 216 217 if (len->is_valid()) { 218 strw(len, Address(obj, arrayOopDesc::length_offset_in_bytes())); 219 } else if (UseCompressedClassPointers && !UseCompactObjectHeaders) { 220 store_klass_gap(obj, zr); 221 } 222 } 223 224 // preserves obj, destroys len_in_bytes 225 // 226 // Scratch registers: t1 = r10, t2 = r11 227 // 228 void C1_MacroAssembler::initialize_body(Register obj, Register len_in_bytes, int hdr_size_in_bytes, Register t1, Register t2) { 229 assert(hdr_size_in_bytes >= 0, "header size must be positive or 0"); 230 assert(t1 == r10 && t2 == r11, "must be"); 231 232 Label done; 233 234 // len_in_bytes is positive and ptr sized 235 subs(len_in_bytes, len_in_bytes, hdr_size_in_bytes); 236 br(Assembler::EQ, done); 237 238 // Zero first 4 bytes, if start offset is not word aligned. 239 if (!is_aligned(hdr_size_in_bytes, BytesPerWord)) { 240 strw(zr, Address(obj, hdr_size_in_bytes)); 241 hdr_size_in_bytes += BytesPerInt; 242 } 243 244 // zero_words() takes ptr in r10 and count in words in r11 245 mov(rscratch1, len_in_bytes); 246 lea(t1, Address(obj, hdr_size_in_bytes)); 247 lsr(t2, rscratch1, LogBytesPerWord); 248 zero_words(t1, t2); 249 250 bind(done); 251 } 252 253 254 void C1_MacroAssembler::allocate_object(Register obj, Register t1, Register t2, int header_size, int object_size, Register klass, Label& slow_case) { 255 assert_different_registers(obj, t1, t2); // XXX really? 256 assert(header_size >= 0 && object_size >= header_size, "illegal sizes"); 257 258 try_allocate(obj, noreg, object_size * BytesPerWord, t1, t2, slow_case); 259 260 initialize_object(obj, klass, noreg, object_size * HeapWordSize, t1, t2, UseTLAB); 261 } 262 263 // Scratch registers: t1 = r10, t2 = r11 264 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) { 265 assert((con_size_in_bytes & MinObjAlignmentInBytesMask) == 0, 266 "con_size_in_bytes is not multiple of alignment"); 267 const int hdr_size_in_bytes = instanceOopDesc::header_size() * HeapWordSize; 268 269 initialize_header(obj, klass, noreg, t1, t2); 270 271 if (!(UseTLAB && ZeroTLAB && is_tlab_allocated)) { 272 // clear rest of allocated space 273 const Register index = t2; 274 if (var_size_in_bytes != noreg) { 275 mov(index, var_size_in_bytes); 276 initialize_body(obj, index, hdr_size_in_bytes, t1, t2); 277 } else if (con_size_in_bytes > hdr_size_in_bytes) { 278 con_size_in_bytes -= hdr_size_in_bytes; 279 lea(t1, Address(obj, hdr_size_in_bytes)); 280 zero_words(t1, con_size_in_bytes / BytesPerWord); 281 } 282 } 283 284 membar(StoreStore); 285 286 if (CURRENT_ENV->dtrace_alloc_probes()) { 287 assert(obj == r0, "must be"); 288 far_call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id))); 289 } 290 291 verify_oop(obj); 292 } 293 void C1_MacroAssembler::allocate_array(Register obj, Register len, Register t1, Register t2, int base_offset_in_bytes, int f, Register klass, Label& slow_case) { 294 assert_different_registers(obj, len, t1, t2, klass); 295 296 // determine alignment mask 297 assert(!(BytesPerWord & 1), "must be a multiple of 2 for masking code to work"); 298 299 // check for negative or excessive length 300 mov(rscratch1, (int32_t)max_array_allocation_length); 301 cmp(len, rscratch1); 302 br(Assembler::HS, slow_case); 303 304 const Register arr_size = t2; // okay to be the same 305 // align object end 306 mov(arr_size, (int32_t)base_offset_in_bytes + MinObjAlignmentInBytesMask); 307 add(arr_size, arr_size, len, ext::uxtw, f); 308 andr(arr_size, arr_size, ~MinObjAlignmentInBytesMask); 309 310 try_allocate(obj, arr_size, 0, t1, t2, slow_case); 311 312 initialize_header(obj, klass, len, t1, t2); 313 314 // clear rest of allocated space 315 initialize_body(obj, arr_size, base_offset_in_bytes, t1, t2); 316 317 membar(StoreStore); 318 319 if (CURRENT_ENV->dtrace_alloc_probes()) { 320 assert(obj == r0, "must be"); 321 far_call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id))); 322 } 323 324 verify_oop(obj); 325 } 326 327 328 void C1_MacroAssembler::inline_cache_check(Register receiver, Register iCache) { 329 verify_oop(receiver); 330 // explicit NULL check not needed since load from [klass_offset] causes a trap 331 // check against inline cache 332 if (UseCompactObjectHeaders) { 333 assert(!MacroAssembler::needs_explicit_null_check(oopDesc::mark_offset_in_bytes()), "must add explicit null check"); 334 } else { 335 assert(!MacroAssembler::needs_explicit_null_check(oopDesc::klass_offset_in_bytes()), "must add explicit null check"); 336 } 337 cmp_klass(receiver, iCache, rscratch1); 338 } 339 340 341 void C1_MacroAssembler::build_frame(int framesize, int bang_size_in_bytes) { 342 assert(bang_size_in_bytes >= framesize, "stack bang size incorrect"); 343 // Make sure there is enough stack space for this method's activation. 344 // Note that we do this before creating a frame. 345 generate_stack_overflow_check(bang_size_in_bytes); 346 MacroAssembler::build_frame(framesize); 347 348 // Insert nmethod entry barrier into frame. 349 BarrierSetAssembler* bs = BarrierSet::barrier_set()->barrier_set_assembler(); 350 bs->nmethod_entry_barrier(this); 351 } 352 353 void C1_MacroAssembler::remove_frame(int framesize) { 354 MacroAssembler::remove_frame(framesize); 355 } 356 357 358 void C1_MacroAssembler::verified_entry(bool breakAtEntry) { 359 // If we have to make this method not-entrant we'll overwrite its 360 // first instruction with a jump. For this action to be legal we 361 // must ensure that this first instruction is a B, BL, NOP, BKPT, 362 // SVC, HVC, or SMC. Make it a NOP. 363 nop(); 364 } 365 366 void C1_MacroAssembler::load_parameter(int offset_in_words, Register reg) { 367 // rbp, + 0: link 368 // + 1: return address 369 // + 2: argument with offset 0 370 // + 3: argument with offset 1 371 // + 4: ... 372 373 ldr(reg, Address(rfp, (offset_in_words + 2) * BytesPerWord)); 374 } 375 376 #ifndef PRODUCT 377 378 void C1_MacroAssembler::verify_stack_oop(int stack_offset) { 379 if (!VerifyOops) return; 380 verify_oop_addr(Address(sp, stack_offset), "oop"); 381 } 382 383 void C1_MacroAssembler::verify_not_null_oop(Register r) { 384 if (!VerifyOops) return; 385 Label not_null; 386 cbnz(r, not_null); 387 stop("non-null oop required"); 388 bind(not_null); 389 verify_oop(r); 390 } 391 392 void C1_MacroAssembler::invalidate_registers(bool inv_r0, bool inv_r19, bool inv_r2, bool inv_r3, bool inv_r4, bool inv_r5) { 393 #ifdef ASSERT 394 static int nn; 395 if (inv_r0) mov(r0, 0xDEAD); 396 if (inv_r19) mov(r19, 0xDEAD); 397 if (inv_r2) mov(r2, nn++); 398 if (inv_r3) mov(r3, 0xDEAD); 399 if (inv_r4) mov(r4, 0xDEAD); 400 if (inv_r5) mov(r5, 0xDEAD); 401 #endif 402 } 403 #endif // ifndef PRODUCT