1 /* 2 * Copyright (c) 1999, 2024, 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 "compiler/compilerDefinitions.inline.hpp" 29 #include "gc/shared/barrierSet.hpp" 30 #include "gc/shared/barrierSetAssembler.hpp" 31 #include "gc/shared/collectedHeap.hpp" 32 #include "gc/shared/tlab_globals.hpp" 33 #include "interpreter/interpreter.hpp" 34 #include "oops/arrayOop.hpp" 35 #include "oops/markWord.hpp" 36 #include "runtime/basicLock.hpp" 37 #include "runtime/globals.hpp" 38 #include "runtime/os.hpp" 39 #include "runtime/sharedRuntime.hpp" 40 #include "runtime/stubRoutines.hpp" 41 #include "utilities/globalDefinitions.hpp" 42 43 int C1_MacroAssembler::lock_object(Register hdr, Register obj, Register disp_hdr, Register tmp, Label& slow_case) { 44 const int aligned_mask = BytesPerWord -1; 45 const int hdr_offset = oopDesc::mark_offset_in_bytes(); 46 assert(hdr == rax, "hdr must be rax, for the cmpxchg instruction"); 47 assert_different_registers(hdr, obj, disp_hdr, tmp); 48 int null_check_offset = -1; 49 50 verify_oop(obj); 51 52 // save object being locked into the BasicObjectLock 53 movptr(Address(disp_hdr, BasicObjectLock::obj_offset()), obj); 54 55 null_check_offset = offset(); 56 57 if (DiagnoseSyncOnValueBasedClasses != 0) { 58 load_klass(hdr, obj, rscratch1); 59 movl(hdr, Address(hdr, Klass::access_flags_offset())); 60 testl(hdr, JVM_ACC_IS_VALUE_BASED_CLASS); 61 jcc(Assembler::notZero, slow_case); 62 } 63 64 if (LockingMode == LM_LIGHTWEIGHT) { 65 #ifdef _LP64 66 const Register thread = r15_thread; 67 #else 68 const Register thread = disp_hdr; 69 get_thread(thread); 70 #endif 71 lightweight_lock(obj, hdr, thread, tmp, slow_case); 72 } else if (LockingMode == LM_LEGACY) { 73 Label done; 74 // Load object header 75 movptr(hdr, Address(obj, hdr_offset)); 76 // and mark it as unlocked 77 orptr(hdr, markWord::unlocked_value); 78 // save unlocked object header into the displaced header location on the stack 79 movptr(Address(disp_hdr, 0), hdr); 80 // test if object header is still the same (i.e. unlocked), and if so, store the 81 // displaced header address in the object header - if it is not the same, get the 82 // object header instead 83 MacroAssembler::lock(); // must be immediately before cmpxchg! 84 cmpxchgptr(disp_hdr, Address(obj, hdr_offset)); 85 // if the object header was the same, we're done 86 jcc(Assembler::equal, done); 87 // if the object header was not the same, it is now in the hdr register 88 // => test if it is a stack pointer into the same stack (recursive locking), i.e.: 89 // 90 // 1) (hdr & aligned_mask) == 0 91 // 2) rsp <= hdr 92 // 3) hdr <= rsp + page_size 93 // 94 // these 3 tests can be done by evaluating the following expression: 95 // 96 // (hdr - rsp) & (aligned_mask - page_size) 97 // 98 // assuming both the stack pointer and page_size have their least 99 // significant 2 bits cleared and page_size is a power of 2 100 subptr(hdr, rsp); 101 andptr(hdr, aligned_mask - (int)os::vm_page_size()); 102 // for recursive locking, the result is zero => save it in the displaced header 103 // location (null in the displaced hdr location indicates recursive locking) 104 movptr(Address(disp_hdr, 0), hdr); 105 // otherwise we don't care about the result and handle locking via runtime call 106 jcc(Assembler::notZero, slow_case); 107 // done 108 bind(done); 109 } 110 111 inc_held_monitor_count(); 112 113 return null_check_offset; 114 } 115 116 void C1_MacroAssembler::unlock_object(Register hdr, Register obj, Register disp_hdr, Label& slow_case) { 117 const int aligned_mask = BytesPerWord -1; 118 const int hdr_offset = oopDesc::mark_offset_in_bytes(); 119 assert(disp_hdr == rax, "disp_hdr must be rax, for the cmpxchg instruction"); 120 assert(hdr != obj && hdr != disp_hdr && obj != disp_hdr, "registers must be different"); 121 Label done; 122 123 if (LockingMode != LM_LIGHTWEIGHT) { 124 // load displaced header 125 movptr(hdr, Address(disp_hdr, 0)); 126 // if the loaded hdr is null we had recursive locking 127 testptr(hdr, hdr); 128 // if we had recursive locking, we are done 129 jcc(Assembler::zero, done); 130 } 131 132 // load object 133 movptr(obj, Address(disp_hdr, BasicObjectLock::obj_offset())); 134 verify_oop(obj); 135 136 if (LockingMode == LM_LIGHTWEIGHT) { 137 #ifdef _LP64 138 lightweight_unlock(obj, disp_hdr, r15_thread, hdr, slow_case); 139 #else 140 // This relies on the implementation of lightweight_unlock being able to handle 141 // that the reg_rax and thread Register parameters may alias each other. 142 get_thread(disp_hdr); 143 lightweight_unlock(obj, disp_hdr, disp_hdr, hdr, slow_case); 144 #endif 145 } else if (LockingMode == LM_LEGACY) { 146 // test if object header is pointing to the displaced header, and if so, restore 147 // the displaced header in the object - if the object header is not pointing to 148 // the displaced header, get the object header instead 149 MacroAssembler::lock(); // must be immediately before cmpxchg! 150 cmpxchgptr(hdr, Address(obj, hdr_offset)); 151 // if the object header was not pointing to the displaced header, 152 // we do unlocking via runtime call 153 jcc(Assembler::notEqual, slow_case); 154 // done 155 } 156 bind(done); 157 dec_held_monitor_count(); 158 } 159 160 161 // Defines obj, preserves var_size_in_bytes 162 void C1_MacroAssembler::try_allocate(Register obj, Register var_size_in_bytes, int con_size_in_bytes, Register t1, Register t2, Label& slow_case) { 163 if (UseTLAB) { 164 tlab_allocate(noreg, obj, var_size_in_bytes, con_size_in_bytes, t1, t2, slow_case); 165 } else { 166 jmp(slow_case); 167 } 168 } 169 170 171 void C1_MacroAssembler::initialize_header(Register obj, Register klass, Register len, Register t1, Register t2) { 172 assert_different_registers(obj, klass, len, t1, t2); 173 #ifdef _LP64 174 if (UseCompactObjectHeaders) { 175 movptr(t1, Address(klass, Klass::prototype_header_offset())); 176 movptr(Address(obj, oopDesc::mark_offset_in_bytes()), t1); 177 } else if (UseCompressedClassPointers) { // Take care not to kill klass 178 movptr(Address(obj, oopDesc::mark_offset_in_bytes()), checked_cast<int32_t>(markWord::prototype().value())); 179 movptr(t1, klass); 180 encode_klass_not_null(t1, rscratch1); 181 movl(Address(obj, oopDesc::klass_offset_in_bytes()), t1); 182 } else 183 #endif 184 { 185 movptr(Address(obj, oopDesc::mark_offset_in_bytes()), checked_cast<int32_t>(markWord::prototype().value())); 186 movptr(Address(obj, oopDesc::klass_offset_in_bytes()), klass); 187 } 188 189 if (len->is_valid()) { 190 movl(Address(obj, arrayOopDesc::length_offset_in_bytes()), len); 191 } 192 #ifdef _LP64 193 else if (UseCompressedClassPointers && !UseCompactObjectHeaders) { 194 xorptr(t1, t1); 195 store_klass_gap(obj, t1); 196 } 197 #endif 198 } 199 200 201 // preserves obj, destroys len_in_bytes 202 void C1_MacroAssembler::initialize_body(Register obj, Register len_in_bytes, int hdr_size_in_bytes, Register t1) { 203 assert(hdr_size_in_bytes >= 0, "header size must be positive or 0"); 204 Label done; 205 206 // len_in_bytes is positive and ptr sized 207 subptr(len_in_bytes, hdr_size_in_bytes); 208 zero_memory(obj, len_in_bytes, hdr_size_in_bytes, t1); 209 bind(done); 210 } 211 212 213 void C1_MacroAssembler::allocate_object(Register obj, Register t1, Register t2, int header_size, int object_size, Register klass, Label& slow_case) { 214 assert(obj == rax, "obj must be in rax, for cmpxchg"); 215 assert_different_registers(obj, t1, t2); // XXX really? 216 assert(header_size >= 0 && object_size >= header_size, "illegal sizes"); 217 218 try_allocate(obj, noreg, object_size * BytesPerWord, t1, t2, slow_case); 219 220 initialize_object(obj, klass, noreg, object_size * HeapWordSize, t1, t2, UseTLAB); 221 } 222 223 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) { 224 assert((con_size_in_bytes & MinObjAlignmentInBytesMask) == 0, 225 "con_size_in_bytes is not multiple of alignment"); 226 const int hdr_size_in_bytes = instanceOopDesc::header_size() * HeapWordSize; 227 assert(!UseCompactObjectHeaders || hdr_size_in_bytes == 8, "check object headers size"); 228 229 initialize_header(obj, klass, noreg, t1, t2); 230 231 if (!(UseTLAB && ZeroTLAB && is_tlab_allocated)) { 232 // clear rest of allocated space 233 const Register t1_zero = t1; 234 const Register index = t2; 235 const int threshold = 6 * BytesPerWord; // approximate break even point for code size (see comments below) 236 if (var_size_in_bytes != noreg) { 237 mov(index, var_size_in_bytes); 238 initialize_body(obj, index, hdr_size_in_bytes, t1_zero); 239 } else if (con_size_in_bytes <= threshold) { 240 // use explicit null stores 241 // code size = 2 + 3*n bytes (n = number of fields to clear) 242 xorptr(t1_zero, t1_zero); // use t1_zero reg to clear memory (shorter code) 243 for (int i = hdr_size_in_bytes; i < con_size_in_bytes; i += BytesPerWord) 244 movptr(Address(obj, i), t1_zero); 245 } else if (con_size_in_bytes > hdr_size_in_bytes) { 246 // use loop to null out the fields 247 // code size = 16 bytes for even n (n = number of fields to clear) 248 // initialize last object field first if odd number of fields 249 xorptr(t1_zero, t1_zero); // use t1_zero reg to clear memory (shorter code) 250 movptr(index, (con_size_in_bytes - hdr_size_in_bytes) >> 3); 251 // initialize last object field if constant size is odd 252 if (((con_size_in_bytes - hdr_size_in_bytes) & 4) != 0) 253 movptr(Address(obj, con_size_in_bytes - (1*BytesPerWord)), t1_zero); 254 // initialize remaining object fields: rdx is a multiple of 2 255 { Label loop; 256 bind(loop); 257 movptr(Address(obj, index, Address::times_8, hdr_size_in_bytes - (1*BytesPerWord)), 258 t1_zero); 259 NOT_LP64(movptr(Address(obj, index, Address::times_8, hdr_size_in_bytes - (2*BytesPerWord)), 260 t1_zero);) 261 decrement(index); 262 jcc(Assembler::notZero, loop); 263 } 264 } 265 } 266 267 if (CURRENT_ENV->dtrace_alloc_probes()) { 268 assert(obj == rax, "must be"); 269 call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id))); 270 } 271 272 verify_oop(obj); 273 } 274 275 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) { 276 assert(obj == rax, "obj must be in rax, for cmpxchg"); 277 assert_different_registers(obj, len, t1, t2, klass); 278 279 // determine alignment mask 280 assert(!(BytesPerWord & 1), "must be a multiple of 2 for masking code to work"); 281 282 // check for negative or excessive length 283 cmpptr(len, checked_cast<int32_t>(max_array_allocation_length)); 284 jcc(Assembler::above, slow_case); 285 286 const Register arr_size = t2; // okay to be the same 287 // align object end 288 movptr(arr_size, base_offset_in_bytes + MinObjAlignmentInBytesMask); 289 lea(arr_size, Address(arr_size, len, f)); 290 andptr(arr_size, ~MinObjAlignmentInBytesMask); 291 292 try_allocate(obj, arr_size, 0, t1, t2, slow_case); 293 294 initialize_header(obj, klass, len, t1, t2); 295 296 // Clear leading 4 bytes, if necessary. 297 // TODO: This could perhaps go into initialize_body() and also clear the leading 4 bytes 298 // for non-array objects, thereby replacing the klass-gap clearing code in initialize_header(). 299 int base_offset = base_offset_in_bytes; 300 #ifdef _LP64 301 if (!is_aligned(base_offset, BytesPerWord)) { 302 assert(is_aligned(base_offset, BytesPerInt), "must be 4-byte aligned"); 303 movl(Address(obj, base_offset), 0); 304 base_offset += BytesPerInt; 305 } 306 #endif 307 assert(is_aligned(base_offset, BytesPerWord), "must be word aligned"); 308 309 // clear rest of allocated space 310 const Register len_zero = len; 311 initialize_body(obj, arr_size, base_offset, len_zero); 312 313 if (CURRENT_ENV->dtrace_alloc_probes()) { 314 assert(obj == rax, "must be"); 315 call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id))); 316 } 317 318 verify_oop(obj); 319 } 320 321 322 323 void C1_MacroAssembler::inline_cache_check(Register receiver, Register iCache) { 324 verify_oop(receiver); 325 // explicit null check not needed since load from [klass_offset] causes a trap 326 // check against inline cache. This is checked in Universe::genesis(). 327 int start_offset = offset(); 328 329 if (UseCompressedClassPointers) { 330 load_klass(rscratch1, receiver, rscratch2); 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) { 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 BarrierSetAssembler* bs = BarrierSet::barrier_set()->barrier_set_assembler(); 366 // C1 code is not hot enough to micro optimize the nmethod entry barrier with an out-of-line stub 367 bs->nmethod_entry_barrier(this, nullptr /* slow_path */, nullptr /* continuation */); 368 } 369 370 371 void C1_MacroAssembler::remove_frame(int frame_size_in_bytes) { 372 increment(rsp, frame_size_in_bytes); // Does not emit code for frame_size == 0 373 pop(rbp); 374 } 375 376 377 void C1_MacroAssembler::verified_entry(bool breakAtEntry) { 378 if (breakAtEntry || VerifyFPU) { 379 // Verified Entry first instruction should be 5 bytes long for correct 380 // patching by patch_verified_entry(). 381 // 382 // Breakpoint and VerifyFPU have one byte first instruction. 383 // Also first instruction will be one byte "push(rbp)" if stack banging 384 // code is not generated (see build_frame() above). 385 // For all these cases generate long instruction first. 386 fat_nop(); 387 } 388 if (breakAtEntry) int3(); 389 // build frame 390 IA32_ONLY( verify_FPU(0, "method_entry"); ) 391 } 392 393 void C1_MacroAssembler::load_parameter(int offset_in_words, Register reg) { 394 // rbp, + 0: link 395 // + 1: return address 396 // + 2: argument with offset 0 397 // + 3: argument with offset 1 398 // + 4: ... 399 400 movptr(reg, Address(rbp, (offset_in_words + 2) * BytesPerWord)); 401 } 402 403 #ifndef PRODUCT 404 405 void C1_MacroAssembler::verify_stack_oop(int stack_offset) { 406 if (!VerifyOops) return; 407 verify_oop_addr(Address(rsp, stack_offset)); 408 } 409 410 void C1_MacroAssembler::verify_not_null_oop(Register r) { 411 if (!VerifyOops) return; 412 Label not_null; 413 testptr(r, r); 414 jcc(Assembler::notZero, not_null); 415 stop("non-null oop required"); 416 bind(not_null); 417 verify_oop(r); 418 } 419 420 void C1_MacroAssembler::invalidate_registers(bool inv_rax, bool inv_rbx, bool inv_rcx, bool inv_rdx, bool inv_rsi, bool inv_rdi) { 421 #ifdef ASSERT 422 if (inv_rax) movptr(rax, 0xDEAD); 423 if (inv_rbx) movptr(rbx, 0xDEAD); 424 if (inv_rcx) movptr(rcx, 0xDEAD); 425 if (inv_rdx) movptr(rdx, 0xDEAD); 426 if (inv_rsi) movptr(rsi, 0xDEAD); 427 if (inv_rdi) movptr(rdi, 0xDEAD); 428 #endif 429 } 430 431 #endif // ifndef PRODUCT --- EOF ---