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 "code/compiledIC.hpp" 29 #include "compiler/compilerDefinitions.inline.hpp" 30 #include "gc/shared/barrierSet.hpp" 31 #include "gc/shared/barrierSetAssembler.hpp" 32 #include "gc/shared/collectedHeap.hpp" 33 #include "gc/shared/tlab_globals.hpp" 34 #include "interpreter/interpreter.hpp" 35 #include "oops/arrayOop.hpp" 36 #include "oops/markWord.hpp" 37 #include "runtime/basicLock.hpp" 38 #include "runtime/globals.hpp" 39 #include "runtime/os.hpp" 40 #include "runtime/sharedRuntime.hpp" 41 #include "runtime/stubRoutines.hpp" 42 #include "utilities/checkedCast.hpp" 43 #include "utilities/globalDefinitions.hpp" 44 45 int C1_MacroAssembler::lock_object(Register hdr, Register obj, Register disp_hdr, Register tmp, Label& slow_case) { 46 const int aligned_mask = BytesPerWord -1; 47 const int hdr_offset = oopDesc::mark_offset_in_bytes(); 48 assert(hdr == rax, "hdr must be rax, for the cmpxchg instruction"); 49 assert_different_registers(hdr, obj, disp_hdr, tmp); 50 int null_check_offset = -1; 51 52 verify_oop(obj); 53 54 // save object being locked into the BasicObjectLock 55 movptr(Address(disp_hdr, BasicObjectLock::obj_offset()), obj); 56 57 null_check_offset = offset(); 58 59 if (DiagnoseSyncOnValueBasedClasses != 0) { 60 load_klass(hdr, obj, rscratch1); 61 movl(hdr, Address(hdr, Klass::access_flags_offset())); 62 testl(hdr, JVM_ACC_IS_VALUE_BASED_CLASS); 63 jcc(Assembler::notZero, slow_case); 64 } 65 66 if (LockingMode == LM_LIGHTWEIGHT) { 67 #ifdef _LP64 68 const Register thread = r15_thread; 69 #else 70 const Register thread = disp_hdr; 71 get_thread(thread); 72 #endif 73 lightweight_lock(obj, hdr, thread, tmp, slow_case); 74 } else if (LockingMode == LM_LEGACY) { 75 Label done; 76 // Load object header 77 movptr(hdr, Address(obj, hdr_offset)); 78 // and mark it as unlocked 79 orptr(hdr, markWord::unlocked_value); 80 // save unlocked object header into the displaced header location on the stack 81 movptr(Address(disp_hdr, 0), hdr); 82 // test if object header is still the same (i.e. unlocked), and if so, store the 83 // displaced header address in the object header - if it is not the same, get the 84 // object header instead 85 MacroAssembler::lock(); // must be immediately before cmpxchg! 86 cmpxchgptr(disp_hdr, Address(obj, hdr_offset)); 87 // if the object header was the same, we're done 88 jcc(Assembler::equal, done); 89 // if the object header was not the same, it is now in the hdr register 90 // => test if it is a stack pointer into the same stack (recursive locking), i.e.: 91 // 92 // 1) (hdr & aligned_mask) == 0 93 // 2) rsp <= hdr 94 // 3) hdr <= rsp + page_size 95 // 96 // these 3 tests can be done by evaluating the following expression: 97 // 98 // (hdr - rsp) & (aligned_mask - page_size) 99 // 100 // assuming both the stack pointer and page_size have their least 101 // significant 2 bits cleared and page_size is a power of 2 102 subptr(hdr, rsp); 103 andptr(hdr, aligned_mask - (int)os::vm_page_size()); 104 // for recursive locking, the result is zero => save it in the displaced header 105 // location (null in the displaced hdr location indicates recursive locking) 106 movptr(Address(disp_hdr, 0), hdr); 107 // otherwise we don't care about the result and handle locking via runtime call 108 jcc(Assembler::notZero, slow_case); 109 // done 110 bind(done); 111 } 112 113 inc_held_monitor_count(); 114 115 return null_check_offset; 116 } 117 118 void C1_MacroAssembler::unlock_object(Register hdr, Register obj, Register disp_hdr, Label& slow_case) { 119 const int aligned_mask = BytesPerWord -1; 120 const int hdr_offset = oopDesc::mark_offset_in_bytes(); 121 assert(disp_hdr == rax, "disp_hdr must be rax, for the cmpxchg instruction"); 122 assert(hdr != obj && hdr != disp_hdr && obj != disp_hdr, "registers must be different"); 123 Label done; 124 125 if (LockingMode != LM_LIGHTWEIGHT) { 126 // load displaced header 127 movptr(hdr, Address(disp_hdr, 0)); 128 // if the loaded hdr is null we had recursive locking 129 testptr(hdr, hdr); 130 // if we had recursive locking, we are done 131 jcc(Assembler::zero, done); 132 } 133 134 // load object 135 movptr(obj, Address(disp_hdr, BasicObjectLock::obj_offset())); 136 verify_oop(obj); 137 138 if (LockingMode == LM_LIGHTWEIGHT) { 139 #ifdef _LP64 140 lightweight_unlock(obj, disp_hdr, r15_thread, hdr, slow_case); 141 #else 142 // This relies on the implementation of lightweight_unlock being able to handle 143 // that the reg_rax and thread Register parameters may alias each other. 144 get_thread(disp_hdr); 145 lightweight_unlock(obj, disp_hdr, disp_hdr, hdr, slow_case); 146 #endif 147 } else if (LockingMode == LM_LEGACY) { 148 // test if object header is pointing to the displaced header, and if so, restore 149 // the displaced header in the object - if the object header is not pointing to 150 // the displaced header, get the object header instead 151 MacroAssembler::lock(); // must be immediately before cmpxchg! 152 cmpxchgptr(hdr, Address(obj, hdr_offset)); 153 // if the object header was not pointing to the displaced header, 154 // we do unlocking via runtime call 155 jcc(Assembler::notEqual, slow_case); 156 // done 157 } 158 bind(done); 159 dec_held_monitor_count(); 160 } 161 162 163 // Defines obj, preserves var_size_in_bytes 164 void C1_MacroAssembler::try_allocate(Register obj, Register var_size_in_bytes, int con_size_in_bytes, Register t1, Register t2, Label& slow_case) { 165 if (UseTLAB) { 166 tlab_allocate(noreg, obj, var_size_in_bytes, con_size_in_bytes, t1, t2, slow_case); 167 } else { 168 jmp(slow_case); 169 } 170 } 171 172 173 void C1_MacroAssembler::initialize_header(Register obj, Register klass, Register len, Register t1, Register t2) { 174 assert_different_registers(obj, klass, len); 175 movptr(Address(obj, oopDesc::mark_offset_in_bytes()), checked_cast<int32_t>(markWord::prototype().value())); 176 #ifdef _LP64 177 if (UseCompressedClassPointers) { // Take care not to kill klass 178 movptr(t1, klass); 179 encode_klass_not_null(t1, rscratch1); 180 movl(Address(obj, oopDesc::klass_offset_in_bytes()), t1); 181 } else 182 #endif 183 { 184 movptr(Address(obj, oopDesc::klass_offset_in_bytes()), klass); 185 } 186 187 if (len->is_valid()) { 188 movl(Address(obj, arrayOopDesc::length_offset_in_bytes()), len); 189 } 190 #ifdef _LP64 191 else if (UseCompressedClassPointers) { 192 xorptr(t1, t1); 193 store_klass_gap(obj, t1); 194 } 195 #endif 196 } 197 198 199 // preserves obj, destroys len_in_bytes 200 void C1_MacroAssembler::initialize_body(Register obj, Register len_in_bytes, int hdr_size_in_bytes, Register t1) { 201 assert(hdr_size_in_bytes >= 0, "header size must be positive or 0"); 202 Label done; 203 204 // len_in_bytes is positive and ptr sized 205 subptr(len_in_bytes, hdr_size_in_bytes); 206 zero_memory(obj, len_in_bytes, hdr_size_in_bytes, t1); 207 bind(done); 208 } 209 210 211 void C1_MacroAssembler::allocate_object(Register obj, Register t1, Register t2, int header_size, int object_size, Register klass, Label& slow_case) { 212 assert(obj == rax, "obj must be in rax, for cmpxchg"); 213 assert_different_registers(obj, t1, t2); // XXX really? 214 assert(header_size >= 0 && object_size >= header_size, "illegal sizes"); 215 216 try_allocate(obj, noreg, object_size * BytesPerWord, t1, t2, slow_case); 217 218 initialize_object(obj, klass, noreg, object_size * HeapWordSize, t1, t2, UseTLAB); 219 } 220 221 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) { 222 assert((con_size_in_bytes & MinObjAlignmentInBytesMask) == 0, 223 "con_size_in_bytes is not multiple of alignment"); 224 const int hdr_size_in_bytes = instanceOopDesc::header_size() * HeapWordSize; 225 226 initialize_header(obj, klass, noreg, t1, t2); 227 228 if (!(UseTLAB && ZeroTLAB && is_tlab_allocated)) { 229 // clear rest of allocated space 230 const Register t1_zero = t1; 231 const Register index = t2; 232 const int threshold = 6 * BytesPerWord; // approximate break even point for code size (see comments below) 233 if (var_size_in_bytes != noreg) { 234 mov(index, var_size_in_bytes); 235 initialize_body(obj, index, hdr_size_in_bytes, t1_zero); 236 } else if (con_size_in_bytes <= threshold) { 237 // use explicit null stores 238 // code size = 2 + 3*n bytes (n = number of fields to clear) 239 xorptr(t1_zero, t1_zero); // use t1_zero reg to clear memory (shorter code) 240 for (int i = hdr_size_in_bytes; i < con_size_in_bytes; i += BytesPerWord) 241 movptr(Address(obj, i), t1_zero); 242 } else if (con_size_in_bytes > hdr_size_in_bytes) { 243 // use loop to null out the fields 244 // code size = 16 bytes for even n (n = number of fields to clear) 245 // initialize last object field first if odd number of fields 246 xorptr(t1_zero, t1_zero); // use t1_zero reg to clear memory (shorter code) 247 movptr(index, (con_size_in_bytes - hdr_size_in_bytes) >> 3); 248 // initialize last object field if constant size is odd 249 if (((con_size_in_bytes - hdr_size_in_bytes) & 4) != 0) 250 movptr(Address(obj, con_size_in_bytes - (1*BytesPerWord)), t1_zero); 251 // initialize remaining object fields: rdx is a multiple of 2 252 { Label loop; 253 bind(loop); 254 movptr(Address(obj, index, Address::times_8, hdr_size_in_bytes - (1*BytesPerWord)), 255 t1_zero); 256 NOT_LP64(movptr(Address(obj, index, Address::times_8, hdr_size_in_bytes - (2*BytesPerWord)), 257 t1_zero);) 258 decrement(index); 259 jcc(Assembler::notZero, loop); 260 } 261 } 262 } 263 264 if (CURRENT_ENV->dtrace_alloc_probes()) { 265 assert(obj == rax, "must be"); 266 call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id))); 267 } 268 269 verify_oop(obj); 270 } 271 272 void C1_MacroAssembler::allocate_array(Register obj, Register len, Register t1, Register t2, int header_size, Address::ScaleFactor f, Register klass, Label& slow_case) { 273 assert(obj == rax, "obj must be in rax, for cmpxchg"); 274 assert_different_registers(obj, len, t1, t2, klass); 275 276 // determine alignment mask 277 assert(!(BytesPerWord & 1), "must be a multiple of 2 for masking code to work"); 278 279 // check for negative or excessive length 280 cmpptr(len, checked_cast<int32_t>(max_array_allocation_length)); 281 jcc(Assembler::above, slow_case); 282 283 const Register arr_size = t2; // okay to be the same 284 // align object end 285 movptr(arr_size, header_size * BytesPerWord + MinObjAlignmentInBytesMask); 286 lea(arr_size, Address(arr_size, len, f)); 287 andptr(arr_size, ~MinObjAlignmentInBytesMask); 288 289 try_allocate(obj, arr_size, 0, t1, t2, slow_case); 290 291 initialize_header(obj, klass, len, t1, t2); 292 293 // clear rest of allocated space 294 const Register len_zero = len; 295 initialize_body(obj, arr_size, header_size * BytesPerWord, len_zero); 296 297 if (CURRENT_ENV->dtrace_alloc_probes()) { 298 assert(obj == rax, "must be"); 299 call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id))); 300 } 301 302 verify_oop(obj); 303 } 304 305 void C1_MacroAssembler::build_frame(int frame_size_in_bytes, int bang_size_in_bytes) { 306 assert(bang_size_in_bytes >= frame_size_in_bytes, "stack bang size incorrect"); 307 // Make sure there is enough stack space for this method's activation. 308 // Note that we do this before doing an enter(). This matches the 309 // ordering of C2's stack overflow check / rsp decrement and allows 310 // the SharedRuntime stack overflow handling to be consistent 311 // between the two compilers. 312 generate_stack_overflow_check(bang_size_in_bytes); 313 314 push(rbp); 315 if (PreserveFramePointer) { 316 mov(rbp, rsp); 317 } 318 #if !defined(_LP64) && defined(COMPILER2) 319 if (UseSSE < 2 && !CompilerConfig::is_c1_only_no_jvmci()) { 320 // c2 leaves fpu stack dirty. Clean it on entry 321 empty_FPU_stack(); 322 } 323 #endif // !_LP64 && COMPILER2 324 decrement(rsp, frame_size_in_bytes); // does not emit code for frame_size == 0 325 326 BarrierSetAssembler* bs = BarrierSet::barrier_set()->barrier_set_assembler(); 327 // C1 code is not hot enough to micro optimize the nmethod entry barrier with an out-of-line stub 328 bs->nmethod_entry_barrier(this, nullptr /* slow_path */, nullptr /* continuation */); 329 } 330 331 332 void C1_MacroAssembler::remove_frame(int frame_size_in_bytes) { 333 increment(rsp, frame_size_in_bytes); // Does not emit code for frame_size == 0 334 pop(rbp); 335 } 336 337 338 void C1_MacroAssembler::verified_entry(bool breakAtEntry) { 339 if (breakAtEntry || VerifyFPU) { 340 // Verified Entry first instruction should be 5 bytes long for correct 341 // patching by patch_verified_entry(). 342 // 343 // Breakpoint and VerifyFPU have one byte first instruction. 344 // Also first instruction will be one byte "push(rbp)" if stack banging 345 // code is not generated (see build_frame() above). 346 // For all these cases generate long instruction first. 347 fat_nop(); 348 } 349 if (breakAtEntry) int3(); 350 // build frame 351 IA32_ONLY( verify_FPU(0, "method_entry"); ) 352 } 353 354 void C1_MacroAssembler::load_parameter(int offset_in_words, Register reg) { 355 // rbp, + 0: link 356 // + 1: return address 357 // + 2: argument with offset 0 358 // + 3: argument with offset 1 359 // + 4: ... 360 361 movptr(reg, Address(rbp, (offset_in_words + 2) * BytesPerWord)); 362 } 363 364 #ifndef PRODUCT 365 366 void C1_MacroAssembler::verify_stack_oop(int stack_offset) { 367 if (!VerifyOops) return; 368 verify_oop_addr(Address(rsp, stack_offset)); 369 } 370 371 void C1_MacroAssembler::verify_not_null_oop(Register r) { 372 if (!VerifyOops) return; 373 Label not_null; 374 testptr(r, r); 375 jcc(Assembler::notZero, not_null); 376 stop("non-null oop required"); 377 bind(not_null); 378 verify_oop(r); 379 } 380 381 void C1_MacroAssembler::invalidate_registers(bool inv_rax, bool inv_rbx, bool inv_rcx, bool inv_rdx, bool inv_rsi, bool inv_rdi) { 382 #ifdef ASSERT 383 if (inv_rax) movptr(rax, 0xDEAD); 384 if (inv_rbx) movptr(rbx, 0xDEAD); 385 if (inv_rcx) movptr(rcx, 0xDEAD); 386 if (inv_rdx) movptr(rdx, 0xDEAD); 387 if (inv_rsi) movptr(rsi, 0xDEAD); 388 if (inv_rdi) movptr(rdi, 0xDEAD); 389 #endif 390 } 391 392 #endif // ifndef PRODUCT