1 /* 2 * Copyright (c) 1999, 2021, 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 "gc/shared/barrierSet.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 int C1_MacroAssembler::lock_object(Register hdr, Register obj, Register disp_hdr, Register scratch, Label& slow_case) { 42 const Register rklass_decode_tmp = LP64_ONLY(rscratch1) NOT_LP64(noreg); 43 const int aligned_mask = BytesPerWord -1; 44 const int hdr_offset = oopDesc::mark_offset_in_bytes(); 45 assert(hdr == rax, "hdr must be rax, for the cmpxchg instruction"); 46 assert_different_registers(hdr, obj, disp_hdr, scratch); 47 int null_check_offset = -1; 48 49 verify_oop(obj); 50 51 // save object being locked into the BasicObjectLock 52 movptr(Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes()), obj); 53 54 null_check_offset = offset(); 55 56 if (DiagnoseSyncOnValueBasedClasses != 0) { 57 load_klass(hdr, obj, rklass_decode_tmp); 58 movl(hdr, Address(hdr, Klass::access_flags_offset())); 59 testl(hdr, JVM_ACC_IS_VALUE_BASED_CLASS); 60 jcc(Assembler::notZero, slow_case); 61 } 62 63 if (LockingMode == LM_LIGHTWEIGHT) { 64 #ifdef _LP64 65 const Register thread = r15_thread; 66 #else 67 const Register thread = disp_hdr; 68 get_thread(thread); 69 #endif 70 // Load object header 71 movptr(hdr, Address(obj, hdr_offset)); 72 fast_lock_impl(obj, hdr, thread, scratch, slow_case); 73 } else { 74 Label done; 75 76 if (UseBiasedLocking) { 77 assert(scratch != noreg, "should have scratch register at this point"); 78 biased_locking_enter(disp_hdr, obj, hdr, scratch, rklass_decode_tmp, false, done, &slow_case); 79 } 80 81 // Load object header 82 movptr(hdr, Address(obj, hdr_offset)); 83 // and mark it as unlocked 84 orptr(hdr, markWord::unlocked_value); 85 // save unlocked object header into the displaced header location on the stack 86 movptr(Address(disp_hdr, 0), hdr); 87 // test if object header is still the same (i.e. unlocked), and if so, store the 88 // displaced header address in the object header - if it is not the same, get the 89 // object header instead 90 MacroAssembler::lock(); // must be immediately before cmpxchg! 91 cmpxchgptr(disp_hdr, Address(obj, hdr_offset)); 92 // if the object header was the same, we're done 93 if (PrintBiasedLockingStatistics) { 94 cond_inc32(Assembler::equal, 95 ExternalAddress((address)BiasedLocking::fast_path_entry_count_addr())); 96 } 97 jcc(Assembler::equal, done); 98 // if the object header was not the same, it is now in the hdr register 99 // => test if it is a stack pointer into the same stack (recursive locking), i.e.: 100 // 101 // 1) (hdr & aligned_mask) == 0 102 // 2) rsp <= hdr 103 // 3) hdr <= rsp + page_size 104 // 105 // these 3 tests can be done by evaluating the following expression: 106 // 107 // (hdr - rsp) & (aligned_mask - page_size) 108 // 109 // assuming both the stack pointer and page_size have their least 110 // significant 2 bits cleared and page_size is a power of 2 111 subptr(hdr, rsp); 112 andptr(hdr, aligned_mask - os::vm_page_size()); 113 // for recursive locking, the result is zero => save it in the displaced header 114 // location (NULL in the displaced hdr location indicates recursive locking) 115 movptr(Address(disp_hdr, 0), hdr); 116 // otherwise we don't care about the result and handle locking via runtime call 117 jcc(Assembler::notZero, slow_case); 118 // done 119 bind(done); 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(disp_hdr == rax, "disp_hdr must be rax, for the cmpxchg instruction"); 129 assert(hdr != obj && hdr != disp_hdr && obj != disp_hdr, "registers must be different"); 130 131 if (LockingMode == LM_LIGHTWEIGHT) { 132 // load object 133 movptr(obj, Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes())); 134 verify_oop(obj); 135 movptr(disp_hdr, Address(obj, hdr_offset)); 136 andptr(disp_hdr, ~(int32_t)markWord::lock_mask_in_place); 137 fast_unlock_impl(obj, disp_hdr, hdr, slow_case); 138 } else { 139 Label done; 140 141 if (UseBiasedLocking) { 142 // load object 143 movptr(obj, Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes())); 144 biased_locking_exit(obj, hdr, done); 145 } 146 147 // load displaced header 148 movptr(hdr, Address(disp_hdr, 0)); 149 // if the loaded hdr is NULL we had recursive locking 150 testptr(hdr, hdr); 151 // if we had recursive locking, we are done 152 jcc(Assembler::zero, done); 153 if (!UseBiasedLocking) { 154 // load object 155 movptr(obj, Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes())); 156 } 157 verify_oop(obj); 158 // test if object header is pointing to the displaced header, and if so, restore 159 // the displaced header in the object - if the object header is not pointing to 160 // the displaced header, get the object header instead 161 MacroAssembler::lock(); // must be immediately before cmpxchg! 162 cmpxchgptr(hdr, Address(obj, hdr_offset)); 163 // if the object header was not pointing to the displaced header, 164 // we do unlocking via runtime call 165 jcc(Assembler::notEqual, slow_case); 166 // done 167 bind(done); 168 } 169 } 170 171 172 // Defines obj, preserves var_size_in_bytes 173 void C1_MacroAssembler::try_allocate(Register obj, Register var_size_in_bytes, int con_size_in_bytes, Register t1, Register t2, Label& slow_case) { 174 if (UseTLAB) { 175 tlab_allocate(noreg, obj, var_size_in_bytes, con_size_in_bytes, t1, t2, slow_case); 176 } else { 177 eden_allocate(noreg, obj, var_size_in_bytes, con_size_in_bytes, t1, slow_case); 178 } 179 } 180 181 182 void C1_MacroAssembler::initialize_header(Register obj, Register klass, Register len, Register t1, Register t2) { 183 assert_different_registers(obj, klass, len, t1, t2); 184 if (UseCompactObjectHeaders || (UseBiasedLocking && !len->is_valid())) { 185 movptr(t1, Address(klass, Klass::prototype_header_offset())); 186 movptr(Address(obj, oopDesc::mark_offset_in_bytes()), t1); 187 } else { 188 movptr(Address(obj, oopDesc::mark_offset_in_bytes()), checked_cast<int32_t>(markWord::prototype().value())); 189 } 190 191 if (!UseCompactObjectHeaders) { 192 #ifdef _LP64 193 if (UseCompressedClassPointers) { // Take care not to kill klass 194 movptr(t1, klass); 195 encode_klass_not_null(t1, rscratch1); 196 movl(Address(obj, oopDesc::klass_offset_in_bytes()), t1); 197 } else 198 #endif 199 { 200 movptr(Address(obj, oopDesc::klass_offset_in_bytes()), klass); 201 } 202 } 203 if (len->is_valid()) { 204 movl(Address(obj, arrayOopDesc::length_offset_in_bytes()), len); 205 } 206 #ifdef _LP64 207 else if (UseCompressedClassPointers && !UseCompactObjectHeaders) { 208 xorptr(t1, t1); 209 store_klass_gap(obj, t1); 210 } 211 #endif 212 } 213 214 215 // preserves obj, destroys len_in_bytes 216 void C1_MacroAssembler::initialize_body(Register obj, Register len_in_bytes, int hdr_size_in_bytes, Register t1) { 217 assert(hdr_size_in_bytes >= 0, "header size must be positive or 0"); 218 Label done; 219 220 // len_in_bytes is positive and ptr sized 221 subptr(len_in_bytes, hdr_size_in_bytes); 222 jcc(Assembler::zero, done); 223 zero_memory(obj, len_in_bytes, hdr_size_in_bytes, t1); 224 bind(done); 225 } 226 227 228 void C1_MacroAssembler::allocate_object(Register obj, Register t1, Register t2, int header_size, int object_size, Register klass, Label& slow_case) { 229 assert(obj == rax, "obj must be in rax, for cmpxchg"); 230 assert_different_registers(obj, t1, t2); // XXX really? 231 assert(header_size >= 0 && object_size >= header_size, "illegal sizes"); 232 233 try_allocate(obj, noreg, object_size * BytesPerWord, t1, t2, slow_case); 234 235 initialize_object(obj, klass, noreg, object_size * HeapWordSize, t1, t2, UseTLAB); 236 } 237 238 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) { 239 assert((con_size_in_bytes & MinObjAlignmentInBytesMask) == 0, 240 "con_size_in_bytes is not multiple of alignment"); 241 const int hdr_size_in_bytes = instanceOopDesc::header_size() * HeapWordSize; 242 243 initialize_header(obj, klass, noreg, t1, t2); 244 245 if (!(UseTLAB && ZeroTLAB && is_tlab_allocated)) { 246 // clear rest of allocated space 247 const Register t1_zero = t1; 248 const Register index = t2; 249 const int threshold = 6 * BytesPerWord; // approximate break even point for code size (see comments below) 250 int hdr_size_aligned = align_up(hdr_size_in_bytes, BytesPerWord); // klass gap is already cleared by init_header(). 251 if (var_size_in_bytes != noreg) { 252 mov(index, var_size_in_bytes); 253 initialize_body(obj, index, hdr_size_aligned, t1_zero); 254 } else if (con_size_in_bytes <= threshold) { 255 // use explicit null stores 256 // code size = 2 + 3*n bytes (n = number of fields to clear) 257 xorptr(t1_zero, t1_zero); // use t1_zero reg to clear memory (shorter code) 258 for (int i = hdr_size_aligned; i < con_size_in_bytes; i += BytesPerWord) 259 movptr(Address(obj, i), t1_zero); 260 } else if (con_size_in_bytes > hdr_size_aligned) { 261 // use loop to null out the fields 262 // code size = 16 bytes for even n (n = number of fields to clear) 263 // initialize last object field first if odd number of fields 264 xorptr(t1_zero, t1_zero); // use t1_zero reg to clear memory (shorter code) 265 movptr(index, (con_size_in_bytes - hdr_size_in_bytes) >> 3); 266 // initialize last object field if constant size is odd 267 if (((con_size_in_bytes - hdr_size_aligned) & 4) != 0) 268 movptr(Address(obj, con_size_in_bytes - (1*BytesPerWord)), t1_zero); 269 // initialize remaining object fields: rdx is a multiple of 2 270 { Label loop; 271 bind(loop); 272 movptr(Address(obj, index, Address::times_8, hdr_size_aligned - (1*BytesPerWord)), 273 t1_zero); 274 NOT_LP64(movptr(Address(obj, index, Address::times_8, hdr_size_aligned - (2*BytesPerWord)), 275 t1_zero);) 276 decrement(index); 277 jcc(Assembler::notZero, loop); 278 } 279 } 280 } 281 282 if (CURRENT_ENV->dtrace_alloc_probes()) { 283 assert(obj == rax, "must be"); 284 call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id))); 285 } 286 287 verify_oop(obj); 288 } 289 290 void C1_MacroAssembler::allocate_array(Register obj, Register len, Register t1, Register t2, int base_offset_in_bytes, Address::ScaleFactor f, Register klass, Label& slow_case) { 291 assert(obj == rax, "obj must be in rax, for cmpxchg"); 292 assert_different_registers(obj, len, t1, t2, klass); 293 294 // determine alignment mask 295 assert(!(BytesPerWord & 1), "must be a multiple of 2 for masking code to work"); 296 297 // check for negative or excessive length 298 cmpptr(len, (int32_t)max_array_allocation_length); 299 jcc(Assembler::above, slow_case); 300 301 const Register arr_size = t2; // okay to be the same 302 // align object end 303 movptr(arr_size, (int32_t)base_offset_in_bytes + MinObjAlignmentInBytesMask); 304 lea(arr_size, Address(arr_size, len, f)); 305 andptr(arr_size, ~MinObjAlignmentInBytesMask); 306 307 try_allocate(obj, arr_size, 0, t1, t2, slow_case); 308 309 initialize_header(obj, klass, len, t1, t2); 310 311 // clear rest of allocated space 312 const Register len_zero = len; 313 initialize_body(obj, arr_size, base_offset_in_bytes, len_zero); 314 315 if (CURRENT_ENV->dtrace_alloc_probes()) { 316 assert(obj == rax, "must be"); 317 call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id))); 318 } 319 320 verify_oop(obj); 321 } 322 323 324 325 void C1_MacroAssembler::inline_cache_check(Register receiver, Register iCache) { 326 verify_oop(receiver); 327 // explicit NULL check not needed since load from [klass_offset] causes a trap 328 // check against inline cache 329 assert(!MacroAssembler::needs_explicit_null_check(oopDesc::klass_offset_in_bytes()), "must add explicit null check"); 330 int start_offset = offset(); 331 Register tmp_load_klass = LP64_ONLY(rscratch2) NOT_LP64(noreg); 332 333 if (UseCompressedClassPointers) { 334 load_klass(rscratch1, receiver, tmp_load_klass); 335 cmpptr(rscratch1, iCache); 336 } else { 337 cmpptr(iCache, Address(receiver, oopDesc::klass_offset_in_bytes())); 338 } 339 // if icache check fails, then jump to runtime routine 340 // Note: RECEIVER must still contain the receiver! 341 jump_cc(Assembler::notEqual, 342 RuntimeAddress(SharedRuntime::get_ic_miss_stub())); 343 const int ic_cmp_size = LP64_ONLY(10) NOT_LP64(9); 344 assert(UseCompressedClassPointers || offset() - start_offset == ic_cmp_size, "check alignment in emit_method_entry"); 345 } 346 347 348 void C1_MacroAssembler::build_frame(int frame_size_in_bytes, int bang_size_in_bytes) { 349 assert(bang_size_in_bytes >= frame_size_in_bytes, "stack bang size incorrect"); 350 // Make sure there is enough stack space for this method's activation. 351 // Note that we do this before doing an enter(). This matches the 352 // ordering of C2's stack overflow check / rsp decrement and allows 353 // the SharedRuntime stack overflow handling to be consistent 354 // between the two compilers. 355 generate_stack_overflow_check(bang_size_in_bytes); 356 357 push(rbp); 358 if (PreserveFramePointer) { 359 mov(rbp, rsp); 360 } 361 #if !defined(_LP64) && defined(COMPILER2) 362 if (UseSSE < 2 && !CompilerConfig::is_c1_only_no_jvmci()) { 363 // c2 leaves fpu stack dirty. Clean it on entry 364 empty_FPU_stack(); 365 } 366 #endif // !_LP64 && COMPILER2 367 decrement(rsp, frame_size_in_bytes); // does not emit code for frame_size == 0 368 369 BarrierSetAssembler* bs = BarrierSet::barrier_set()->barrier_set_assembler(); 370 bs->nmethod_entry_barrier(this); 371 } 372 373 374 void C1_MacroAssembler::remove_frame(int frame_size_in_bytes) { 375 increment(rsp, frame_size_in_bytes); // Does not emit code for frame_size == 0 376 pop(rbp); 377 } 378 379 380 void C1_MacroAssembler::verified_entry(bool breakAtEntry) { 381 if (breakAtEntry || VerifyFPU) { 382 // Verified Entry first instruction should be 5 bytes long for correct 383 // patching by patch_verified_entry(). 384 // 385 // Breakpoint and VerifyFPU have one byte first instruction. 386 // Also first instruction will be one byte "push(rbp)" if stack banging 387 // code is not generated (see build_frame() above). 388 // For all these cases generate long instruction first. 389 fat_nop(); 390 } 391 if (breakAtEntry) int3(); 392 // build frame 393 IA32_ONLY( verify_FPU(0, "method_entry"); ) 394 } 395 396 void C1_MacroAssembler::load_parameter(int offset_in_words, Register reg) { 397 // rbp, + 0: link 398 // + 1: return address 399 // + 2: argument with offset 0 400 // + 3: argument with offset 1 401 // + 4: ... 402 403 movptr(reg, Address(rbp, (offset_in_words + 2) * BytesPerWord)); 404 } 405 406 #ifndef PRODUCT 407 408 void C1_MacroAssembler::verify_stack_oop(int stack_offset) { 409 if (!VerifyOops) return; 410 verify_oop_addr(Address(rsp, stack_offset)); 411 } 412 413 void C1_MacroAssembler::verify_not_null_oop(Register r) { 414 if (!VerifyOops) return; 415 Label not_null; 416 testptr(r, r); 417 jcc(Assembler::notZero, not_null); 418 stop("non-null oop required"); 419 bind(not_null); 420 verify_oop(r); 421 } 422 423 void C1_MacroAssembler::invalidate_registers(bool inv_rax, bool inv_rbx, bool inv_rcx, bool inv_rdx, bool inv_rsi, bool inv_rdi) { 424 #ifdef ASSERT 425 if (inv_rax) movptr(rax, 0xDEAD); 426 if (inv_rbx) movptr(rbx, 0xDEAD); 427 if (inv_rcx) movptr(rcx, 0xDEAD); 428 if (inv_rdx) movptr(rdx, 0xDEAD); 429 if (inv_rsi) movptr(rsi, 0xDEAD); 430 if (inv_rdi) movptr(rdi, 0xDEAD); 431 #endif 432 } 433 434 #endif // ifndef PRODUCT