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_in_bytes()), 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 (UseFastLocking) { 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, LP64_ONLY(false) NOT_LP64(true)); 73 } else { 74 Label done; 75 orptr(hdr, markWord::unlocked_value); 76 // save unlocked object header into the displaced header location on the stack 77 movptr(Address(disp_hdr, 0), hdr); 78 // test if object header is still the same (i.e. unlocked), and if so, store the 79 // displaced header address in the object header - if it is not the same, get the 80 // object header instead 81 MacroAssembler::lock(); // must be immediately before cmpxchg! 82 cmpxchgptr(disp_hdr, Address(obj, hdr_offset)); 83 // if the object header was the same, we're done 84 jcc(Assembler::equal, done); 85 // if the object header was not the same, it is now in the hdr register 86 // => test if it is a stack pointer into the same stack (recursive locking), i.e.: 87 // 88 // 1) (hdr & aligned_mask) == 0 89 // 2) rsp <= hdr 90 // 3) hdr <= rsp + page_size 91 // 92 // these 3 tests can be done by evaluating the following expression: 93 // 94 // (hdr - rsp) & (aligned_mask - page_size) 95 // 96 // assuming both the stack pointer and page_size have their least 97 // significant 2 bits cleared and page_size is a power of 2 98 subptr(hdr, rsp); 99 andptr(hdr, aligned_mask - (int)os::vm_page_size()); 100 // for recursive locking, the result is zero => save it in the displaced header 101 // location (NULL in the displaced hdr location indicates recursive locking) 102 movptr(Address(disp_hdr, 0), hdr); 103 // otherwise we don't care about the result and handle locking via runtime call 104 jcc(Assembler::notZero, slow_case); 105 // done 106 bind(done); 107 } 108 109 inc_held_monitor_count(); 110 111 return null_check_offset; 112 } 113 114 void C1_MacroAssembler::unlock_object(Register hdr, Register obj, Register disp_hdr, Label& slow_case) { 115 const int aligned_mask = BytesPerWord -1; 116 const int hdr_offset = oopDesc::mark_offset_in_bytes(); 117 assert(disp_hdr == rax, "disp_hdr must be rax, for the cmpxchg instruction"); 118 assert(hdr != obj && hdr != disp_hdr && obj != disp_hdr, "registers must be different"); 119 Label done; 120 121 if (!UseFastLocking) { 122 // load displaced header 123 movptr(hdr, Address(disp_hdr, 0)); 124 // if the loaded hdr is NULL we had recursive locking 125 testptr(hdr, hdr); 126 // if we had recursive locking, we are done 127 jcc(Assembler::zero, done); 128 } 129 130 // load object 131 movptr(obj, Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes())); 132 verify_oop(obj); 133 134 if (UseFastLocking) { 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 // test if object header is pointing to the displaced header, and if so, restore 140 // the displaced header in the object - if the object header is not pointing to 141 // the displaced header, get the object header instead 142 MacroAssembler::lock(); // must be immediately before cmpxchg! 143 cmpxchgptr(hdr, Address(obj, hdr_offset)); 144 // if the object header was not pointing to the displaced header, 145 // we do unlocking via runtime call 146 jcc(Assembler::notEqual, slow_case); 147 // done 148 } 149 bind(done); 150 dec_held_monitor_count(); 151 } 152 153 154 // Defines obj, preserves var_size_in_bytes 155 void C1_MacroAssembler::try_allocate(Register obj, Register var_size_in_bytes, int con_size_in_bytes, Register t1, Register t2, Label& slow_case) { 156 if (UseTLAB) { 157 tlab_allocate(noreg, obj, var_size_in_bytes, con_size_in_bytes, t1, t2, slow_case); 158 } else { 159 jmp(slow_case); 160 } 161 } 162 163 164 void C1_MacroAssembler::initialize_header(Register obj, Register klass, Register len, Register t1, Register t2) { 165 assert_different_registers(obj, klass, len, t1, t2); 166 if (UseCompactObjectHeaders) { 167 movptr(t1, Address(klass, Klass::prototype_header_offset())); 168 movptr(Address(obj, oopDesc::mark_offset_in_bytes()), t1); 169 } else { 170 movptr(Address(obj, oopDesc::mark_offset_in_bytes()), checked_cast<int32_t>(markWord::prototype().value())); 171 #ifdef _LP64 172 if (UseCompressedClassPointers) { // Take care not to kill klass 173 movptr(t1, klass); 174 encode_klass_not_null(t1, rscratch1); 175 movl(Address(obj, oopDesc::klass_offset_in_bytes()), t1); 176 } else 177 #endif 178 { 179 movptr(Address(obj, oopDesc::klass_offset_in_bytes()), klass); 180 } 181 } 182 if (len->is_valid()) { 183 movl(Address(obj, arrayOopDesc::length_offset_in_bytes()), len); 184 } 185 #ifdef _LP64 186 else if (UseCompressedClassPointers && !UseCompactObjectHeaders) { 187 xorptr(t1, t1); 188 store_klass_gap(obj, t1); 189 } 190 #endif 191 } 192 193 194 // preserves obj, destroys len_in_bytes 195 void C1_MacroAssembler::initialize_body(Register obj, Register len_in_bytes, int hdr_size_in_bytes, Register t1) { 196 assert(hdr_size_in_bytes >= 0, "header size must be positive or 0"); 197 Label done; 198 199 // len_in_bytes is positive and ptr sized 200 subptr(len_in_bytes, hdr_size_in_bytes); 201 zero_memory(obj, len_in_bytes, hdr_size_in_bytes, t1); 202 bind(done); 203 } 204 205 206 void C1_MacroAssembler::allocate_object(Register obj, Register t1, Register t2, int header_size, int object_size, Register klass, Label& slow_case) { 207 assert(obj == rax, "obj must be in rax, for cmpxchg"); 208 assert_different_registers(obj, t1, t2); // XXX really? 209 assert(header_size >= 0 && object_size >= header_size, "illegal sizes"); 210 211 try_allocate(obj, noreg, object_size * BytesPerWord, t1, t2, slow_case); 212 213 initialize_object(obj, klass, noreg, object_size * HeapWordSize, t1, t2, UseTLAB); 214 } 215 216 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) { 217 assert((con_size_in_bytes & MinObjAlignmentInBytesMask) == 0, 218 "con_size_in_bytes is not multiple of alignment"); 219 const int hdr_size_in_bytes = instanceOopDesc::header_size() * HeapWordSize; 220 221 initialize_header(obj, klass, noreg, t1, t2); 222 223 if (!(UseTLAB && ZeroTLAB && is_tlab_allocated)) { 224 // clear rest of allocated space 225 const Register t1_zero = t1; 226 const Register index = t2; 227 const int threshold = 6 * BytesPerWord; // approximate break even point for code size (see comments below) 228 int hdr_size_aligned = align_up(hdr_size_in_bytes, BytesPerWord); // klass gap is already cleared by init_header(). 229 if (var_size_in_bytes != noreg) { 230 mov(index, var_size_in_bytes); 231 initialize_body(obj, index, hdr_size_aligned, t1_zero); 232 } else if (con_size_in_bytes <= threshold) { 233 // use explicit null stores 234 // code size = 2 + 3*n bytes (n = number of fields to clear) 235 xorptr(t1_zero, t1_zero); // use t1_zero reg to clear memory (shorter code) 236 for (int i = hdr_size_aligned; i < con_size_in_bytes; i += BytesPerWord) 237 movptr(Address(obj, i), t1_zero); 238 } else if (con_size_in_bytes > hdr_size_aligned) { 239 // use loop to null out the fields 240 // code size = 16 bytes for even n (n = number of fields to clear) 241 // initialize last object field first if odd number of fields 242 xorptr(t1_zero, t1_zero); // use t1_zero reg to clear memory (shorter code) 243 movptr(index, (con_size_in_bytes - hdr_size_aligned) >> 3); 244 // initialize last object field if constant size is odd 245 if (((con_size_in_bytes - hdr_size_aligned) & 4) != 0) 246 movptr(Address(obj, con_size_in_bytes - (1*BytesPerWord)), t1_zero); 247 // initialize remaining object fields: rdx is a multiple of 2 248 { Label loop; 249 bind(loop); 250 movptr(Address(obj, index, Address::times_8, hdr_size_aligned - (1*BytesPerWord)), 251 t1_zero); 252 NOT_LP64(movptr(Address(obj, index, Address::times_8, hdr_size_aligned - (2*BytesPerWord)), 253 t1_zero);) 254 decrement(index); 255 jcc(Assembler::notZero, loop); 256 } 257 } 258 } 259 260 if (CURRENT_ENV->dtrace_alloc_probes()) { 261 assert(obj == rax, "must be"); 262 call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id))); 263 } 264 265 verify_oop(obj); 266 } 267 268 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) { 269 assert(obj == rax, "obj must be in rax, for cmpxchg"); 270 assert_different_registers(obj, len, t1, t2, klass); 271 272 // determine alignment mask 273 assert(!(BytesPerWord & 1), "must be a multiple of 2 for masking code to work"); 274 275 // check for negative or excessive length 276 cmpptr(len, checked_cast<int32_t>(max_array_allocation_length)); 277 jcc(Assembler::above, slow_case); 278 279 const Register arr_size = t2; // okay to be the same 280 // align object end 281 movptr(arr_size, (int32_t)base_offset_in_bytes + MinObjAlignmentInBytesMask); 282 lea(arr_size, Address(arr_size, len, f)); 283 andptr(arr_size, ~MinObjAlignmentInBytesMask); 284 285 try_allocate(obj, arr_size, 0, t1, t2, slow_case); 286 287 initialize_header(obj, klass, len, t1, t2); 288 289 // clear rest of allocated space 290 const Register len_zero = len; 291 initialize_body(obj, arr_size, base_offset_in_bytes, len_zero); 292 293 if (CURRENT_ENV->dtrace_alloc_probes()) { 294 assert(obj == rax, "must be"); 295 call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id))); 296 } 297 298 verify_oop(obj); 299 } 300 301 302 303 void C1_MacroAssembler::inline_cache_check(Register receiver, Register iCache) { 304 verify_oop(receiver); 305 // explicit NULL check not needed since load from [klass_offset] causes a trap 306 // check against inline cache 307 assert(!MacroAssembler::needs_explicit_null_check(oopDesc::klass_offset_in_bytes()), "must add explicit null check"); 308 int start_offset = offset(); 309 310 if (UseCompressedClassPointers) { 311 load_klass(rscratch1, receiver, rscratch2); 312 cmpptr(rscratch1, iCache); 313 } else { 314 cmpptr(iCache, Address(receiver, oopDesc::klass_offset_in_bytes())); 315 } 316 // if icache check fails, then jump to runtime routine 317 // Note: RECEIVER must still contain the receiver! 318 jump_cc(Assembler::notEqual, 319 RuntimeAddress(SharedRuntime::get_ic_miss_stub())); 320 const int ic_cmp_size = LP64_ONLY(10) NOT_LP64(9); 321 assert(UseCompressedClassPointers || offset() - start_offset == ic_cmp_size, "check alignment in emit_method_entry"); 322 } 323 324 325 void C1_MacroAssembler::build_frame(int frame_size_in_bytes, int bang_size_in_bytes, int max_monitors) { 326 assert(bang_size_in_bytes >= frame_size_in_bytes, "stack bang size incorrect"); 327 // Make sure there is enough stack space for this method's activation. 328 // Note that we do this before doing an enter(). This matches the 329 // ordering of C2's stack overflow check / rsp decrement and allows 330 // the SharedRuntime stack overflow handling to be consistent 331 // between the two compilers. 332 generate_stack_overflow_check(bang_size_in_bytes); 333 334 push(rbp); 335 if (PreserveFramePointer) { 336 mov(rbp, rsp); 337 } 338 #if !defined(_LP64) && defined(COMPILER2) 339 if (UseSSE < 2 && !CompilerConfig::is_c1_only_no_jvmci()) { 340 // c2 leaves fpu stack dirty. Clean it on entry 341 empty_FPU_stack(); 342 } 343 #endif // !_LP64 && COMPILER2 344 decrement(rsp, frame_size_in_bytes); // does not emit code for frame_size == 0 345 346 #ifdef _LP64 347 if (UseFastLocking && max_monitors > 0) { 348 Label ok; 349 movptr(rax, Address(r15_thread, JavaThread::lock_stack_current_offset())); 350 addptr(rax, max_monitors * wordSize); 351 cmpptr(rax, Address(r15_thread, JavaThread::lock_stack_limit_offset())); 352 jcc(Assembler::less, ok); 353 assert(StubRoutines::x86::check_lock_stack() != NULL, "need runtime call stub"); 354 call(RuntimeAddress(StubRoutines::x86::check_lock_stack())); 355 bind(ok); 356 } 357 #endif 358 359 BarrierSetAssembler* bs = BarrierSet::barrier_set()->barrier_set_assembler(); 360 // C1 code is not hot enough to micro optimize the nmethod entry barrier with an out-of-line stub 361 bs->nmethod_entry_barrier(this, NULL /* slow_path */, NULL /* continuation */); 362 } 363 364 365 void C1_MacroAssembler::remove_frame(int frame_size_in_bytes) { 366 increment(rsp, frame_size_in_bytes); // Does not emit code for frame_size == 0 367 pop(rbp); 368 } 369 370 371 void C1_MacroAssembler::verified_entry(bool breakAtEntry) { 372 if (breakAtEntry || VerifyFPU) { 373 // Verified Entry first instruction should be 5 bytes long for correct 374 // patching by patch_verified_entry(). 375 // 376 // Breakpoint and VerifyFPU have one byte first instruction. 377 // Also first instruction will be one byte "push(rbp)" if stack banging 378 // code is not generated (see build_frame() above). 379 // For all these cases generate long instruction first. 380 fat_nop(); 381 } 382 if (breakAtEntry) int3(); 383 // build frame 384 IA32_ONLY( verify_FPU(0, "method_entry"); ) 385 } 386 387 void C1_MacroAssembler::load_parameter(int offset_in_words, Register reg) { 388 // rbp, + 0: link 389 // + 1: return address 390 // + 2: argument with offset 0 391 // + 3: argument with offset 1 392 // + 4: ... 393 394 movptr(reg, Address(rbp, (offset_in_words + 2) * BytesPerWord)); 395 } 396 397 #ifndef PRODUCT 398 399 void C1_MacroAssembler::verify_stack_oop(int stack_offset) { 400 if (!VerifyOops) return; 401 verify_oop_addr(Address(rsp, stack_offset)); 402 } 403 404 void C1_MacroAssembler::verify_not_null_oop(Register r) { 405 if (!VerifyOops) return; 406 Label not_null; 407 testptr(r, r); 408 jcc(Assembler::notZero, not_null); 409 stop("non-null oop required"); 410 bind(not_null); 411 verify_oop(r); 412 } 413 414 void C1_MacroAssembler::invalidate_registers(bool inv_rax, bool inv_rbx, bool inv_rcx, bool inv_rdx, bool inv_rsi, bool inv_rdi) { 415 #ifdef ASSERT 416 if (inv_rax) movptr(rax, 0xDEAD); 417 if (inv_rbx) movptr(rbx, 0xDEAD); 418 if (inv_rcx) movptr(rcx, 0xDEAD); 419 if (inv_rdx) movptr(rdx, 0xDEAD); 420 if (inv_rsi) movptr(rsi, 0xDEAD); 421 if (inv_rdi) movptr(rdi, 0xDEAD); 422 #endif 423 } 424 425 #endif // ifndef PRODUCT