1 /* 2 * Copyright (c) 1999, 2023, 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/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 tmp, Label& slow_case) { 42 const int aligned_mask = BytesPerWord -1; 43 const int hdr_offset = oopDesc::mark_offset_in_bytes(); 44 assert(hdr == rax, "hdr must be rax, for the cmpxchg instruction"); 45 assert_different_registers(hdr, obj, disp_hdr, tmp); 46 int null_check_offset = -1; 47 48 verify_oop(obj); 49 50 // save object being locked into the BasicObjectLock 51 movptr(Address(disp_hdr, BasicObjectLock::obj_offset()), obj); 52 53 null_check_offset = offset(); 54 55 if (DiagnoseSyncOnValueBasedClasses != 0) { 56 load_klass(hdr, obj, rscratch1); 57 movl(hdr, Address(hdr, Klass::access_flags_offset())); 58 testl(hdr, JVM_ACC_IS_VALUE_BASED_CLASS); 59 jcc(Assembler::notZero, slow_case); 60 } 61 62 // Load object header 63 movptr(hdr, Address(obj, hdr_offset)); 64 65 if (LockingMode == LM_LIGHTWEIGHT) { 66 #ifdef _LP64 67 const Register thread = r15_thread; 68 #else 69 const Register thread = disp_hdr; 70 get_thread(thread); 71 #endif 72 fast_lock_impl(obj, hdr, thread, tmp, slow_case); 73 } else if (LockingMode == LM_LEGACY) { 74 Label done; 75 // and mark it as unlocked 76 orptr(hdr, markWord::unlocked_value); 77 // save unlocked object header into the displaced header location on the stack 78 movptr(Address(disp_hdr, 0), hdr); 79 // test if object header is still the same (i.e. unlocked), and if so, store the 80 // displaced header address in the object header - if it is not the same, get the 81 // object header instead 82 MacroAssembler::lock(); // must be immediately before cmpxchg! 83 cmpxchgptr(disp_hdr, Address(obj, hdr_offset)); 84 // if the object header was the same, we're done 85 jcc(Assembler::equal, done); 86 // if the object header was not the same, it is now in the hdr register 87 // => test if it is a stack pointer into the same stack (recursive locking), i.e.: 88 // 89 // 1) (hdr & aligned_mask) == 0 90 // 2) rsp <= hdr 91 // 3) hdr <= rsp + page_size 92 // 93 // these 3 tests can be done by evaluating the following expression: 94 // 95 // (hdr - rsp) & (aligned_mask - page_size) 96 // 97 // assuming both the stack pointer and page_size have their least 98 // significant 2 bits cleared and page_size is a power of 2 99 subptr(hdr, rsp); 100 andptr(hdr, aligned_mask - (int)os::vm_page_size()); 101 // for recursive locking, the result is zero => save it in the displaced header 102 // location (null in the displaced hdr location indicates recursive locking) 103 movptr(Address(disp_hdr, 0), hdr); 104 // otherwise we don't care about the result and handle locking via runtime call 105 jcc(Assembler::notZero, slow_case); 106 // done 107 bind(done); 108 } 109 110 inc_held_monitor_count(); 111 112 return null_check_offset; 113 } 114 115 void C1_MacroAssembler::unlock_object(Register hdr, Register obj, Register disp_hdr, Label& slow_case) { 116 const int aligned_mask = BytesPerWord -1; 117 const int hdr_offset = oopDesc::mark_offset_in_bytes(); 118 assert(disp_hdr == rax, "disp_hdr must be rax, for the cmpxchg instruction"); 119 assert(hdr != obj && hdr != disp_hdr && obj != disp_hdr, "registers must be different"); 120 Label done; 121 122 if (LockingMode != LM_LIGHTWEIGHT) { 123 // load displaced header 124 movptr(hdr, Address(disp_hdr, 0)); 125 // if the loaded hdr is null we had recursive locking 126 testptr(hdr, hdr); 127 // if we had recursive locking, we are done 128 jcc(Assembler::zero, done); 129 } 130 131 // load object 132 movptr(obj, Address(disp_hdr, BasicObjectLock::obj_offset())); 133 verify_oop(obj); 134 135 if (LockingMode == LM_LIGHTWEIGHT) { 136 movptr(disp_hdr, Address(obj, hdr_offset)); 137 andptr(disp_hdr, ~(int32_t)markWord::lock_mask_in_place); 138 fast_unlock_impl(obj, disp_hdr, hdr, slow_case); 139 } else if (LockingMode == LM_LEGACY) { 140 // test if object header is pointing to the displaced header, and if so, restore 141 // the displaced header in the object - if the object header is not pointing to 142 // the displaced header, get the object header instead 143 MacroAssembler::lock(); // must be immediately before cmpxchg! 144 cmpxchgptr(hdr, Address(obj, hdr_offset)); 145 // if the object header was not pointing to the displaced header, 146 // we do unlocking via runtime call 147 jcc(Assembler::notEqual, slow_case); 148 // done 149 } 150 bind(done); 151 dec_held_monitor_count(); 152 } 153 154 155 // Defines obj, preserves var_size_in_bytes 156 void C1_MacroAssembler::try_allocate(Register obj, Register var_size_in_bytes, int con_size_in_bytes, Register t1, Register t2, Label& slow_case) { 157 if (UseTLAB) { 158 tlab_allocate(noreg, obj, var_size_in_bytes, con_size_in_bytes, t1, t2, slow_case); 159 } else { 160 jmp(slow_case); 161 } 162 } 163 164 165 void C1_MacroAssembler::initialize_header(Register obj, Register klass, Register len, Register t1, Register t2) { 166 assert_different_registers(obj, klass, len, t1, t2); 167 if (UseCompactObjectHeaders) { 168 movptr(t1, Address(klass, Klass::prototype_header_offset())); 169 movptr(Address(obj, oopDesc::mark_offset_in_bytes()), t1); 170 } else { 171 movptr(Address(obj, oopDesc::mark_offset_in_bytes()), checked_cast<int32_t>(markWord::prototype().value())); 172 #ifdef _LP64 173 if (UseCompressedClassPointers) { // Take care not to kill klass 174 movptr(t1, klass); 175 encode_klass_not_null(t1, rscratch1); 176 movl(Address(obj, oopDesc::klass_offset_in_bytes()), t1); 177 } else 178 #endif 179 { 180 movptr(Address(obj, oopDesc::klass_offset_in_bytes()), klass); 181 } 182 } 183 if (len->is_valid()) { 184 movl(Address(obj, arrayOopDesc::length_offset_in_bytes()), len); 185 } 186 #ifdef _LP64 187 else if (UseCompressedClassPointers && !UseCompactObjectHeaders) { 188 xorptr(t1, t1); 189 store_klass_gap(obj, t1); 190 } 191 #endif 192 } 193 194 195 // preserves obj, destroys len_in_bytes 196 void C1_MacroAssembler::initialize_body(Register obj, Register len_in_bytes, int hdr_size_in_bytes, Register t1) { 197 assert(hdr_size_in_bytes >= 0, "header size must be positive or 0"); 198 Label done; 199 200 // len_in_bytes is positive and ptr sized 201 subptr(len_in_bytes, hdr_size_in_bytes); 202 zero_memory(obj, len_in_bytes, hdr_size_in_bytes, t1); 203 bind(done); 204 } 205 206 207 void C1_MacroAssembler::allocate_object(Register obj, Register t1, Register t2, int header_size, int object_size, Register klass, Label& slow_case) { 208 assert(obj == rax, "obj must be in rax, for cmpxchg"); 209 assert_different_registers(obj, t1, t2); // XXX really? 210 assert(header_size >= 0 && object_size >= header_size, "illegal sizes"); 211 212 try_allocate(obj, noreg, object_size * BytesPerWord, t1, t2, slow_case); 213 214 initialize_object(obj, klass, noreg, object_size * HeapWordSize, t1, t2, UseTLAB); 215 } 216 217 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) { 218 assert((con_size_in_bytes & MinObjAlignmentInBytesMask) == 0, 219 "con_size_in_bytes is not multiple of alignment"); 220 const int hdr_size_in_bytes = instanceOopDesc::header_size() * HeapWordSize; 221 222 initialize_header(obj, klass, noreg, t1, t2); 223 224 if (!(UseTLAB && ZeroTLAB && is_tlab_allocated)) { 225 // clear rest of allocated space 226 const Register t1_zero = t1; 227 const Register index = t2; 228 const int threshold = 6 * BytesPerWord; // approximate break even point for code size (see comments below) 229 int hdr_size_aligned = align_up(hdr_size_in_bytes, BytesPerWord); // klass gap is already cleared by init_header(). 230 if (var_size_in_bytes != noreg) { 231 mov(index, var_size_in_bytes); 232 initialize_body(obj, index, hdr_size_aligned, t1_zero); 233 } else if (con_size_in_bytes <= threshold) { 234 // use explicit null stores 235 // code size = 2 + 3*n bytes (n = number of fields to clear) 236 xorptr(t1_zero, t1_zero); // use t1_zero reg to clear memory (shorter code) 237 for (int i = hdr_size_aligned; i < con_size_in_bytes; i += BytesPerWord) 238 movptr(Address(obj, i), t1_zero); 239 } else if (con_size_in_bytes > hdr_size_aligned) { 240 // use loop to null out the fields 241 // code size = 16 bytes for even n (n = number of fields to clear) 242 // initialize last object field first if odd number of fields 243 xorptr(t1_zero, t1_zero); // use t1_zero reg to clear memory (shorter code) 244 movptr(index, (con_size_in_bytes - hdr_size_aligned) >> 3); 245 // initialize last object field if constant size is odd 246 if (((con_size_in_bytes - hdr_size_aligned) & 4) != 0) 247 movptr(Address(obj, con_size_in_bytes - (1*BytesPerWord)), t1_zero); 248 // initialize remaining object fields: rdx is a multiple of 2 249 { Label loop; 250 bind(loop); 251 movptr(Address(obj, index, Address::times_8, hdr_size_aligned - (1*BytesPerWord)), 252 t1_zero); 253 NOT_LP64(movptr(Address(obj, index, Address::times_8, hdr_size_aligned - (2*BytesPerWord)), 254 t1_zero);) 255 decrement(index); 256 jcc(Assembler::notZero, loop); 257 } 258 } 259 } 260 261 if (CURRENT_ENV->dtrace_alloc_probes()) { 262 assert(obj == rax, "must be"); 263 call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id))); 264 } 265 266 verify_oop(obj); 267 } 268 269 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) { 270 assert(obj == rax, "obj must be in rax, for cmpxchg"); 271 assert_different_registers(obj, len, t1, t2, klass); 272 273 // determine alignment mask 274 assert(!(BytesPerWord & 1), "must be a multiple of 2 for masking code to work"); 275 276 // check for negative or excessive length 277 cmpptr(len, checked_cast<int32_t>(max_array_allocation_length)); 278 jcc(Assembler::above, slow_case); 279 280 const Register arr_size = t2; // okay to be the same 281 // align object end 282 movptr(arr_size, (int32_t)base_offset_in_bytes + MinObjAlignmentInBytesMask); 283 lea(arr_size, Address(arr_size, len, f)); 284 andptr(arr_size, ~MinObjAlignmentInBytesMask); 285 286 try_allocate(obj, arr_size, 0, t1, t2, slow_case); 287 288 initialize_header(obj, klass, len, t1, t2); 289 290 // clear rest of allocated space 291 const Register len_zero = len; 292 initialize_body(obj, arr_size, base_offset_in_bytes, len_zero); 293 294 if (CURRENT_ENV->dtrace_alloc_probes()) { 295 assert(obj == rax, "must be"); 296 call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id))); 297 } 298 299 verify_oop(obj); 300 } 301 302 303 304 void C1_MacroAssembler::inline_cache_check(Register receiver, Register iCache) { 305 verify_oop(receiver); 306 // explicit null check not needed since load from [klass_offset] causes a trap 307 // check against inline cache 308 assert(!MacroAssembler::needs_explicit_null_check(oopDesc::klass_offset_in_bytes()), "must add explicit null check"); 309 int start_offset = offset(); 310 311 if (UseCompressedClassPointers) { 312 load_klass(rscratch1, receiver, rscratch2); 313 cmpptr(rscratch1, iCache); 314 } else { 315 cmpptr(iCache, Address(receiver, oopDesc::klass_offset_in_bytes())); 316 } 317 // if icache check fails, then jump to runtime routine 318 // Note: RECEIVER must still contain the receiver! 319 jump_cc(Assembler::notEqual, 320 RuntimeAddress(SharedRuntime::get_ic_miss_stub())); 321 const int ic_cmp_size = LP64_ONLY(10) NOT_LP64(9); 322 assert(UseCompressedClassPointers || offset() - start_offset == ic_cmp_size, "check alignment in emit_method_entry"); 323 } 324 325 326 void C1_MacroAssembler::build_frame(int frame_size_in_bytes, int bang_size_in_bytes) { 327 assert(bang_size_in_bytes >= frame_size_in_bytes, "stack bang size incorrect"); 328 // Make sure there is enough stack space for this method's activation. 329 // Note that we do this before doing an enter(). This matches the 330 // ordering of C2's stack overflow check / rsp decrement and allows 331 // the SharedRuntime stack overflow handling to be consistent 332 // between the two compilers. 333 generate_stack_overflow_check(bang_size_in_bytes); 334 335 push(rbp); 336 if (PreserveFramePointer) { 337 mov(rbp, rsp); 338 } 339 #if !defined(_LP64) && defined(COMPILER2) 340 if (UseSSE < 2 && !CompilerConfig::is_c1_only_no_jvmci()) { 341 // c2 leaves fpu stack dirty. Clean it on entry 342 empty_FPU_stack(); 343 } 344 #endif // !_LP64 && COMPILER2 345 decrement(rsp, frame_size_in_bytes); // does not emit code for frame_size == 0 346 347 BarrierSetAssembler* bs = BarrierSet::barrier_set()->barrier_set_assembler(); 348 // C1 code is not hot enough to micro optimize the nmethod entry barrier with an out-of-line stub 349 bs->nmethod_entry_barrier(this, nullptr /* slow_path */, nullptr /* continuation */); 350 } 351 352 353 void C1_MacroAssembler::remove_frame(int frame_size_in_bytes) { 354 increment(rsp, frame_size_in_bytes); // Does not emit code for frame_size == 0 355 pop(rbp); 356 } 357 358 359 void C1_MacroAssembler::verified_entry(bool breakAtEntry) { 360 if (breakAtEntry || VerifyFPU) { 361 // Verified Entry first instruction should be 5 bytes long for correct 362 // patching by patch_verified_entry(). 363 // 364 // Breakpoint and VerifyFPU have one byte first instruction. 365 // Also first instruction will be one byte "push(rbp)" if stack banging 366 // code is not generated (see build_frame() above). 367 // For all these cases generate long instruction first. 368 fat_nop(); 369 } 370 if (breakAtEntry) int3(); 371 // build frame 372 IA32_ONLY( verify_FPU(0, "method_entry"); ) 373 } 374 375 void C1_MacroAssembler::load_parameter(int offset_in_words, Register reg) { 376 // rbp, + 0: link 377 // + 1: return address 378 // + 2: argument with offset 0 379 // + 3: argument with offset 1 380 // + 4: ... 381 382 movptr(reg, Address(rbp, (offset_in_words + 2) * BytesPerWord)); 383 } 384 385 #ifndef PRODUCT 386 387 void C1_MacroAssembler::verify_stack_oop(int stack_offset) { 388 if (!VerifyOops) return; 389 verify_oop_addr(Address(rsp, stack_offset)); 390 } 391 392 void C1_MacroAssembler::verify_not_null_oop(Register r) { 393 if (!VerifyOops) return; 394 Label not_null; 395 testptr(r, r); 396 jcc(Assembler::notZero, not_null); 397 stop("non-null oop required"); 398 bind(not_null); 399 verify_oop(r); 400 } 401 402 void C1_MacroAssembler::invalidate_registers(bool inv_rax, bool inv_rbx, bool inv_rcx, bool inv_rdx, bool inv_rsi, bool inv_rdi) { 403 #ifdef ASSERT 404 if (inv_rax) movptr(rax, 0xDEAD); 405 if (inv_rbx) movptr(rbx, 0xDEAD); 406 if (inv_rcx) movptr(rcx, 0xDEAD); 407 if (inv_rdx) movptr(rdx, 0xDEAD); 408 if (inv_rsi) movptr(rsi, 0xDEAD); 409 if (inv_rdi) movptr(rdi, 0xDEAD); 410 #endif 411 } 412 413 #endif // ifndef PRODUCT