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 (UseFastLocking) { 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, LP64_ONLY(false) NOT_LP64(true)); 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 (UseFastLocking) { 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 // Defines obj, preserves var_size_in_bytes 172 void C1_MacroAssembler::try_allocate(Register obj, Register var_size_in_bytes, int con_size_in_bytes, Register t1, Register t2, Label& slow_case) { 173 if (UseTLAB) { 174 tlab_allocate(noreg, obj, var_size_in_bytes, con_size_in_bytes, t1, t2, slow_case); 175 } else { 176 eden_allocate(noreg, obj, var_size_in_bytes, con_size_in_bytes, t1, slow_case); 177 } 178 } 179 180 181 void C1_MacroAssembler::initialize_header(Register obj, Register klass, Register len, Register t1, Register t2) { 182 assert_different_registers(obj, klass, len, t1, t2); 183 if (UseCompactObjectHeaders) { 184 movptr(t1, Address(klass, Klass::prototype_header_offset())); 185 movptr(Address(obj, oopDesc::mark_offset_in_bytes()), t1); 186 } else { 187 movptr(Address(obj, oopDesc::mark_offset_in_bytes()), checked_cast<int32_t>(markWord::prototype().value())); 188 #ifdef _LP64 189 if (UseCompressedClassPointers) { // Take care not to kill klass 190 movptr(t1, klass); 191 encode_klass_not_null(t1, rscratch1); 192 movl(Address(obj, oopDesc::klass_offset_in_bytes()), t1); 193 } else 194 #endif 195 { 196 movptr(Address(obj, oopDesc::klass_offset_in_bytes()), klass); 197 } 198 } 199 if (len->is_valid()) { 200 movl(Address(obj, arrayOopDesc::length_offset_in_bytes()), len); 201 } 202 #ifdef _LP64 203 else if (UseCompressedClassPointers && !UseCompactObjectHeaders) { 204 xorptr(t1, t1); 205 store_klass_gap(obj, t1); 206 } 207 #endif 208 } 209 210 211 // preserves obj, destroys len_in_bytes 212 void C1_MacroAssembler::initialize_body(Register obj, Register len_in_bytes, int hdr_size_in_bytes, Register t1) { 213 assert(hdr_size_in_bytes >= 0, "header size must be positive or 0"); 214 Label done; 215 216 // len_in_bytes is positive and ptr sized 217 subptr(len_in_bytes, hdr_size_in_bytes); 218 jcc(Assembler::zero, done); 219 zero_memory(obj, len_in_bytes, hdr_size_in_bytes, t1); 220 bind(done); 221 } 222 223 224 void C1_MacroAssembler::allocate_object(Register obj, Register t1, Register t2, int header_size, int object_size, Register klass, Label& slow_case) { 225 assert(obj == rax, "obj must be in rax, for cmpxchg"); 226 assert_different_registers(obj, t1, t2); // XXX really? 227 assert(header_size >= 0 && object_size >= header_size, "illegal sizes"); 228 229 try_allocate(obj, noreg, object_size * BytesPerWord, t1, t2, slow_case); 230 231 initialize_object(obj, klass, noreg, object_size * HeapWordSize, t1, t2, UseTLAB); 232 } 233 234 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) { 235 assert((con_size_in_bytes & MinObjAlignmentInBytesMask) == 0, 236 "con_size_in_bytes is not multiple of alignment"); 237 const int hdr_size_in_bytes = instanceOopDesc::header_size() * HeapWordSize; 238 239 initialize_header(obj, klass, noreg, t1, t2); 240 241 if (!(UseTLAB && ZeroTLAB && is_tlab_allocated)) { 242 // clear rest of allocated space 243 const Register t1_zero = t1; 244 const Register index = t2; 245 const int threshold = 6 * BytesPerWord; // approximate break even point for code size (see comments below) 246 int hdr_size_aligned = align_up(hdr_size_in_bytes, BytesPerWord); // klass gap is already cleared by init_header(). 247 if (var_size_in_bytes != noreg) { 248 mov(index, var_size_in_bytes); 249 initialize_body(obj, index, hdr_size_aligned, t1_zero); 250 } else if (con_size_in_bytes <= threshold) { 251 // use explicit null stores 252 // code size = 2 + 3*n bytes (n = number of fields to clear) 253 xorptr(t1_zero, t1_zero); // use t1_zero reg to clear memory (shorter code) 254 for (int i = hdr_size_aligned; i < con_size_in_bytes; i += BytesPerWord) 255 movptr(Address(obj, i), t1_zero); 256 } else if (con_size_in_bytes > hdr_size_aligned) { 257 // use loop to null out the fields 258 // code size = 16 bytes for even n (n = number of fields to clear) 259 // initialize last object field first if odd number of fields 260 xorptr(t1_zero, t1_zero); // use t1_zero reg to clear memory (shorter code) 261 movptr(index, (con_size_in_bytes - hdr_size_in_bytes) >> 3); 262 // initialize last object field if constant size is odd 263 if (((con_size_in_bytes - hdr_size_aligned) & 4) != 0) 264 movptr(Address(obj, con_size_in_bytes - (1*BytesPerWord)), t1_zero); 265 // initialize remaining object fields: rdx is a multiple of 2 266 { Label loop; 267 bind(loop); 268 movptr(Address(obj, index, Address::times_8, hdr_size_aligned - (1*BytesPerWord)), 269 t1_zero); 270 NOT_LP64(movptr(Address(obj, index, Address::times_8, hdr_size_aligned - (2*BytesPerWord)), 271 t1_zero);) 272 decrement(index); 273 jcc(Assembler::notZero, loop); 274 } 275 } 276 } 277 278 if (CURRENT_ENV->dtrace_alloc_probes()) { 279 assert(obj == rax, "must be"); 280 call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id))); 281 } 282 283 verify_oop(obj); 284 } 285 286 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) { 287 assert(obj == rax, "obj must be in rax, for cmpxchg"); 288 assert_different_registers(obj, len, t1, t2, klass); 289 290 // determine alignment mask 291 assert(!(BytesPerWord & 1), "must be a multiple of 2 for masking code to work"); 292 293 // check for negative or excessive length 294 cmpptr(len, (int32_t)max_array_allocation_length); 295 jcc(Assembler::above, slow_case); 296 297 const Register arr_size = t2; // okay to be the same 298 // align object end 299 movptr(arr_size, (int32_t)base_offset_in_bytes + MinObjAlignmentInBytesMask); 300 lea(arr_size, Address(arr_size, len, f)); 301 andptr(arr_size, ~MinObjAlignmentInBytesMask); 302 303 try_allocate(obj, arr_size, 0, t1, t2, slow_case); 304 305 initialize_header(obj, klass, len, t1, t2); 306 307 // clear rest of allocated space 308 const Register len_zero = len; 309 initialize_body(obj, arr_size, base_offset_in_bytes, len_zero); 310 311 if (CURRENT_ENV->dtrace_alloc_probes()) { 312 assert(obj == rax, "must be"); 313 call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id))); 314 } 315 316 verify_oop(obj); 317 } 318 319 320 321 void C1_MacroAssembler::inline_cache_check(Register receiver, Register iCache) { 322 verify_oop(receiver); 323 // explicit NULL check not needed since load from [klass_offset] causes a trap 324 // check against inline cache 325 assert(!MacroAssembler::needs_explicit_null_check(oopDesc::klass_offset_in_bytes()), "must add explicit null check"); 326 int start_offset = offset(); 327 Register tmp_load_klass = LP64_ONLY(rscratch2) NOT_LP64(noreg); 328 329 if (UseCompressedClassPointers) { 330 load_klass(rscratch1, receiver, tmp_load_klass); 331 cmpptr(rscratch1, iCache); 332 } else { 333 cmpptr(iCache, Address(receiver, oopDesc::klass_offset_in_bytes())); 334 } 335 // if icache check fails, then jump to runtime routine 336 // Note: RECEIVER must still contain the receiver! 337 jump_cc(Assembler::notEqual, 338 RuntimeAddress(SharedRuntime::get_ic_miss_stub())); 339 const int ic_cmp_size = LP64_ONLY(10) NOT_LP64(9); 340 assert(UseCompressedClassPointers || offset() - start_offset == ic_cmp_size, "check alignment in emit_method_entry"); 341 } 342 343 344 void C1_MacroAssembler::build_frame(int frame_size_in_bytes, int bang_size_in_bytes, int max_monitors) { 345 assert(bang_size_in_bytes >= frame_size_in_bytes, "stack bang size incorrect"); 346 // Make sure there is enough stack space for this method's activation. 347 // Note that we do this before doing an enter(). This matches the 348 // ordering of C2's stack overflow check / rsp decrement and allows 349 // the SharedRuntime stack overflow handling to be consistent 350 // between the two compilers. 351 generate_stack_overflow_check(bang_size_in_bytes); 352 353 push(rbp); 354 if (PreserveFramePointer) { 355 mov(rbp, rsp); 356 } 357 #if !defined(_LP64) && defined(COMPILER2) 358 if (UseSSE < 2 && !CompilerConfig::is_c1_only_no_jvmci()) { 359 // c2 leaves fpu stack dirty. Clean it on entry 360 empty_FPU_stack(); 361 } 362 #endif // !_LP64 && COMPILER2 363 decrement(rsp, frame_size_in_bytes); // does not emit code for frame_size == 0 364 365 #ifdef _LP64 366 if (UseFastLocking && max_monitors > 0) { 367 Label ok; 368 movptr(rax, Address(r15_thread, JavaThread::lock_stack_current_offset())); 369 addptr(rax, max_monitors * wordSize); 370 cmpptr(rax, Address(r15_thread, JavaThread::lock_stack_limit_offset())); 371 jcc(Assembler::less, ok); 372 assert(StubRoutines::x86::check_lock_stack() != NULL, "need runtime call stub"); 373 call(RuntimeAddress(StubRoutines::x86::check_lock_stack())); 374 bind(ok); 375 } 376 #endif 377 378 BarrierSetAssembler* bs = BarrierSet::barrier_set()->barrier_set_assembler(); 379 bs->nmethod_entry_barrier(this); 380 } 381 382 383 void C1_MacroAssembler::remove_frame(int frame_size_in_bytes) { 384 increment(rsp, frame_size_in_bytes); // Does not emit code for frame_size == 0 385 pop(rbp); 386 } 387 388 389 void C1_MacroAssembler::verified_entry(bool breakAtEntry) { 390 if (breakAtEntry || VerifyFPU) { 391 // Verified Entry first instruction should be 5 bytes long for correct 392 // patching by patch_verified_entry(). 393 // 394 // Breakpoint and VerifyFPU have one byte first instruction. 395 // Also first instruction will be one byte "push(rbp)" if stack banging 396 // code is not generated (see build_frame() above). 397 // For all these cases generate long instruction first. 398 fat_nop(); 399 } 400 if (breakAtEntry) int3(); 401 // build frame 402 IA32_ONLY( verify_FPU(0, "method_entry"); ) 403 } 404 405 void C1_MacroAssembler::load_parameter(int offset_in_words, Register reg) { 406 // rbp, + 0: link 407 // + 1: return address 408 // + 2: argument with offset 0 409 // + 3: argument with offset 1 410 // + 4: ... 411 412 movptr(reg, Address(rbp, (offset_in_words + 2) * BytesPerWord)); 413 } 414 415 #ifndef PRODUCT 416 417 void C1_MacroAssembler::verify_stack_oop(int stack_offset) { 418 if (!VerifyOops) return; 419 verify_oop_addr(Address(rsp, stack_offset)); 420 } 421 422 void C1_MacroAssembler::verify_not_null_oop(Register r) { 423 if (!VerifyOops) return; 424 Label not_null; 425 testptr(r, r); 426 jcc(Assembler::notZero, not_null); 427 stop("non-null oop required"); 428 bind(not_null); 429 verify_oop(r); 430 } 431 432 void C1_MacroAssembler::invalidate_registers(bool inv_rax, bool inv_rbx, bool inv_rcx, bool inv_rdx, bool inv_rsi, bool inv_rdi) { 433 #ifdef ASSERT 434 if (inv_rax) movptr(rax, 0xDEAD); 435 if (inv_rbx) movptr(rbx, 0xDEAD); 436 if (inv_rcx) movptr(rcx, 0xDEAD); 437 if (inv_rdx) movptr(rdx, 0xDEAD); 438 if (inv_rsi) movptr(rsi, 0xDEAD); 439 if (inv_rdi) movptr(rdi, 0xDEAD); 440 #endif 441 } 442 443 #endif // ifndef PRODUCT