1 /* 2 * Copyright (c) 1999, 2015, 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 "classfile/systemDictionary.hpp" 29 #include "gc_interface/collectedHeap.hpp" 30 #include "interpreter/interpreter.hpp" 31 #include "oops/arrayOop.hpp" 32 #include "oops/markOop.hpp" 33 #include "runtime/basicLock.hpp" 34 #include "runtime/biasedLocking.hpp" 35 #include "runtime/os.hpp" 36 #include "runtime/sharedRuntime.hpp" 37 #include "runtime/stubRoutines.hpp" 38 39 int C1_MacroAssembler::lock_object(Register hdr, Register obj, Register disp_hdr, Register scratch, Label& slow_case) { 40 const int aligned_mask = BytesPerWord -1; 41 const int hdr_offset = oopDesc::mark_offset_in_bytes(); 42 assert(hdr == rax, "hdr must be rax, for the cmpxchg instruction"); 43 assert(hdr != obj && hdr != disp_hdr && obj != disp_hdr, "registers must be different"); 44 Label done; 45 int null_check_offset = -1; 46 47 verify_oop(obj); 48 49 // save object being locked into the BasicObjectLock 50 movptr(Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes()), obj); 51 52 if (UseBiasedLocking) { 53 assert(scratch != noreg, "should have scratch register at this point"); 54 null_check_offset = biased_locking_enter(disp_hdr, obj, hdr, scratch, false, done, &slow_case); 55 } else { 56 null_check_offset = offset(); 57 } 58 59 // Load object header 60 movptr(hdr, Address(obj, hdr_offset)); 61 // and mark it as unlocked 62 orptr(hdr, markOopDesc::unlocked_value); 63 // save unlocked object header into the displaced header location on the stack 64 movptr(Address(disp_hdr, 0), hdr); 65 // test if object header is still the same (i.e. unlocked), and if so, store the 66 // displaced header address in the object header - if it is not the same, get the 67 // object header instead 68 if (os::is_MP()) MacroAssembler::lock(); // must be immediately before cmpxchg! 69 cmpxchgptr(disp_hdr, Address(obj, hdr_offset)); 70 // if the object header was the same, we're done 71 if (PrintBiasedLockingStatistics) { 72 cond_inc32(Assembler::equal, 73 ExternalAddress((address)BiasedLocking::fast_path_entry_count_addr())); 74 } 75 jcc(Assembler::equal, done); 76 // if the object header was not the same, it is now in the hdr register 77 // => test if it is a stack pointer into the same stack (recursive locking), i.e.: 78 // 79 // 1) (hdr & aligned_mask) == 0 80 // 2) rsp <= hdr 81 // 3) hdr <= rsp + page_size 82 // 83 // these 3 tests can be done by evaluating the following expression: 84 // 85 // (hdr - rsp) & (aligned_mask - page_size) 86 // 87 // assuming both the stack pointer and page_size have their least 88 // significant 2 bits cleared and page_size is a power of 2 89 subptr(hdr, rsp); 90 andptr(hdr, aligned_mask - os::vm_page_size()); 91 // for recursive locking, the result is zero => save it in the displaced header 92 // location (NULL in the displaced hdr location indicates recursive locking) 93 movptr(Address(disp_hdr, 0), hdr); 94 // otherwise we don't care about the result and handle locking via runtime call 95 jcc(Assembler::notZero, slow_case); 96 // done 97 bind(done); 98 return null_check_offset; 99 } 100 101 102 void C1_MacroAssembler::unlock_object(Register hdr, Register obj, Register disp_hdr, Label& slow_case) { 103 const int aligned_mask = BytesPerWord -1; 104 const int hdr_offset = oopDesc::mark_offset_in_bytes(); 105 assert(disp_hdr == rax, "disp_hdr must be rax, for the cmpxchg instruction"); 106 assert(hdr != obj && hdr != disp_hdr && obj != disp_hdr, "registers must be different"); 107 Label done; 108 109 if (UseBiasedLocking) { 110 // load object 111 movptr(obj, Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes())); 112 biased_locking_exit(obj, hdr, done); 113 } 114 115 // load displaced header 116 movptr(hdr, Address(disp_hdr, 0)); 117 // if the loaded hdr is NULL we had recursive locking 118 testptr(hdr, hdr); 119 // if we had recursive locking, we are done 120 jcc(Assembler::zero, done); 121 if (!UseBiasedLocking) { 122 // load object 123 movptr(obj, Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes())); 124 } 125 verify_oop(obj); 126 // test if object header is pointing to the displaced header, and if so, restore 127 // the displaced header in the object - if the object header is not pointing to 128 // the displaced header, get the object header instead 129 if (os::is_MP()) MacroAssembler::lock(); // must be immediately before cmpxchg! 130 cmpxchgptr(hdr, Address(obj, hdr_offset)); 131 // if the object header was not pointing to the displaced header, 132 // we do unlocking via runtime call 133 jcc(Assembler::notEqual, slow_case); 134 // done 135 bind(done); 136 } 137 138 139 // Defines obj, preserves var_size_in_bytes 140 void C1_MacroAssembler::try_allocate(Register obj, Register var_size_in_bytes, int con_size_in_bytes, Register t1, Register t2, Label& slow_case) { 141 if (UseTLAB) { 142 tlab_allocate(obj, var_size_in_bytes, con_size_in_bytes, t1, t2, slow_case); 143 } else { 144 eden_allocate(obj, var_size_in_bytes, con_size_in_bytes, t1, slow_case); 145 incr_allocated_bytes(noreg, var_size_in_bytes, con_size_in_bytes, t1); 146 } 147 } 148 149 150 void C1_MacroAssembler::initialize_header(Register obj, Register klass, Register len, Register t1, Register t2) { 151 assert_different_registers(obj, klass, len); 152 if (UseBiasedLocking && !len->is_valid()) { 153 assert_different_registers(obj, klass, len, t1, t2); 154 movptr(t1, Address(klass, Klass::prototype_header_offset())); 155 movptr(Address(obj, oopDesc::mark_offset_in_bytes()), t1); 156 } else { 157 // This assumes that all prototype bits fit in an int32_t 158 movptr(Address(obj, oopDesc::mark_offset_in_bytes ()), (int32_t)(intptr_t)markOopDesc::prototype()); 159 } 160 #ifdef _LP64 161 if (UseCompressedClassPointers) { // Take care not to kill klass 162 movptr(t1, klass); 163 encode_klass_not_null(t1); 164 movl(Address(obj, oopDesc::klass_offset_in_bytes()), t1); 165 } else 166 #endif 167 { 168 movptr(Address(obj, oopDesc::klass_offset_in_bytes()), klass); 169 } 170 171 if (len->is_valid()) { 172 movl(Address(obj, arrayOopDesc::length_offset_in_bytes()), len); 173 } 174 #ifdef _LP64 175 else if (UseCompressedClassPointers) { 176 xorptr(t1, t1); 177 store_klass_gap(obj, t1); 178 } 179 #endif 180 } 181 182 183 // preserves obj, destroys len_in_bytes 184 void C1_MacroAssembler::initialize_body(Register obj, Register len_in_bytes, int hdr_size_in_bytes, Register t1) { 185 Label done; 186 assert(obj != len_in_bytes && obj != t1 && t1 != len_in_bytes, "registers must be different"); 187 assert((hdr_size_in_bytes & (BytesPerWord - 1)) == 0, "header size is not a multiple of BytesPerWord"); 188 Register index = len_in_bytes; 189 // index is positive and ptr sized 190 subptr(index, hdr_size_in_bytes); 191 jcc(Assembler::zero, done); 192 // initialize topmost word, divide index by 2, check if odd and test if zero 193 // note: for the remaining code to work, index must be a multiple of BytesPerWord 194 #ifdef ASSERT 195 { Label L; 196 testptr(index, BytesPerWord - 1); 197 jcc(Assembler::zero, L); 198 stop("index is not a multiple of BytesPerWord"); 199 bind(L); 200 } 201 #endif 202 xorptr(t1, t1); // use _zero reg to clear memory (shorter code) 203 if (UseIncDec) { 204 shrptr(index, 3); // divide by 8/16 and set carry flag if bit 2 was set 205 } else { 206 shrptr(index, 2); // use 2 instructions to avoid partial flag stall 207 shrptr(index, 1); 208 } 209 #ifndef _LP64 210 // index could have been not a multiple of 8 (i.e., bit 2 was set) 211 { Label even; 212 // note: if index was a multiple of 8, than it cannot 213 // be 0 now otherwise it must have been 0 before 214 // => if it is even, we don't need to check for 0 again 215 jcc(Assembler::carryClear, even); 216 // clear topmost word (no jump needed if conditional assignment would work here) 217 movptr(Address(obj, index, Address::times_8, hdr_size_in_bytes - 0*BytesPerWord), t1); 218 // index could be 0 now, need to check again 219 jcc(Assembler::zero, done); 220 bind(even); 221 } 222 #endif // !_LP64 223 // initialize remaining object fields: rdx is a multiple of 2 now 224 { Label loop; 225 bind(loop); 226 movptr(Address(obj, index, Address::times_8, hdr_size_in_bytes - 1*BytesPerWord), t1); 227 NOT_LP64(movptr(Address(obj, index, Address::times_8, hdr_size_in_bytes - 2*BytesPerWord), t1);) 228 decrement(index); 229 jcc(Assembler::notZero, loop); 230 } 231 232 // done 233 bind(done); 234 } 235 236 237 void C1_MacroAssembler::allocate_object(Register obj, Register t1, Register t2, int header_size, int object_size, Register klass, Label& slow_case) { 238 assert(obj == rax, "obj must be in rax, for cmpxchg"); 239 assert_different_registers(obj, t1, t2); // XXX really? 240 assert(header_size >= 0 && object_size >= header_size, "illegal sizes"); 241 242 try_allocate(obj, noreg, object_size * BytesPerWord, t1, t2, slow_case); 243 244 initialize_object(obj, klass, noreg, object_size * HeapWordSize, t1, t2); 245 } 246 247 void C1_MacroAssembler::initialize_object(Register obj, Register klass, Register var_size_in_bytes, int con_size_in_bytes, Register t1, Register t2) { 248 assert((con_size_in_bytes & MinObjAlignmentInBytesMask) == 0, 249 "con_size_in_bytes is not multiple of alignment"); 250 const int hdr_size_in_bytes = instanceOopDesc::header_size() * HeapWordSize; 251 252 initialize_header(obj, klass, noreg, t1, t2); 253 254 // clear rest of allocated space 255 const Register t1_zero = t1; 256 const Register index = t2; 257 const int threshold = 6 * BytesPerWord; // approximate break even point for code size (see comments below) 258 if (var_size_in_bytes != noreg) { 259 mov(index, var_size_in_bytes); 260 initialize_body(obj, index, hdr_size_in_bytes, t1_zero); 261 } else if (con_size_in_bytes <= threshold) { 262 // use explicit null stores 263 // code size = 2 + 3*n bytes (n = number of fields to clear) 264 xorptr(t1_zero, t1_zero); // use t1_zero reg to clear memory (shorter code) 265 for (int i = hdr_size_in_bytes; i < con_size_in_bytes; i += BytesPerWord) 266 movptr(Address(obj, i), t1_zero); 267 } else if (con_size_in_bytes > hdr_size_in_bytes) { 268 // use loop to null out the fields 269 // code size = 16 bytes for even n (n = number of fields to clear) 270 // initialize last object field first if odd number of fields 271 xorptr(t1_zero, t1_zero); // use t1_zero reg to clear memory (shorter code) 272 movptr(index, (con_size_in_bytes - hdr_size_in_bytes) >> 3); 273 // initialize last object field if constant size is odd 274 if (((con_size_in_bytes - hdr_size_in_bytes) & 4) != 0) 275 movptr(Address(obj, con_size_in_bytes - (1*BytesPerWord)), t1_zero); 276 // initialize remaining object fields: rdx is a multiple of 2 277 { Label loop; 278 bind(loop); 279 movptr(Address(obj, index, Address::times_8, hdr_size_in_bytes - (1*BytesPerWord)), 280 t1_zero); 281 NOT_LP64(movptr(Address(obj, index, Address::times_8, hdr_size_in_bytes - (2*BytesPerWord)), 282 t1_zero);) 283 decrement(index); 284 jcc(Assembler::notZero, loop); 285 } 286 } 287 288 if (CURRENT_ENV->dtrace_alloc_probes()) { 289 assert(obj == rax, "must be"); 290 call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id))); 291 } 292 293 verify_oop(obj); 294 } 295 296 void C1_MacroAssembler::allocate_array(Register obj, Register len, Register t1, Register t2, int header_size, Address::ScaleFactor f, Register klass, Label& slow_case) { 297 assert(obj == rax, "obj must be in rax, for cmpxchg"); 298 assert_different_registers(obj, len, t1, t2, klass); 299 300 // determine alignment mask 301 assert(!(BytesPerWord & 1), "must be a multiple of 2 for masking code to work"); 302 303 // check for negative or excessive length 304 cmpptr(len, (int32_t)max_array_allocation_length); 305 jcc(Assembler::above, slow_case); 306 307 const Register arr_size = t2; // okay to be the same 308 // align object end 309 movptr(arr_size, (int32_t)header_size * BytesPerWord + MinObjAlignmentInBytesMask); 310 lea(arr_size, Address(arr_size, len, f)); 311 andptr(arr_size, ~MinObjAlignmentInBytesMask); 312 313 try_allocate(obj, arr_size, 0, t1, t2, slow_case); 314 315 initialize_header(obj, klass, len, t1, t2); 316 317 // clear rest of allocated space 318 const Register len_zero = len; 319 initialize_body(obj, arr_size, header_size * BytesPerWord, len_zero); 320 321 if (CURRENT_ENV->dtrace_alloc_probes()) { 322 assert(obj == rax, "must be"); 323 call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id))); 324 } 325 326 verify_oop(obj); 327 } 328 329 330 331 void C1_MacroAssembler::inline_cache_check(Register receiver, Register iCache) { 332 verify_oop(receiver); 333 // explicit NULL check not needed since load from [klass_offset] causes a trap 334 // check against inline cache 335 assert(!MacroAssembler::needs_explicit_null_check(oopDesc::klass_offset_in_bytes()), "must add explicit null check"); 336 int start_offset = offset(); 337 338 if (UseCompressedClassPointers) { 339 load_klass(rscratch1, receiver); 340 cmpptr(rscratch1, iCache); 341 } else { 342 cmpptr(iCache, Address(receiver, oopDesc::klass_offset_in_bytes())); 343 } 344 // if icache check fails, then jump to runtime routine 345 // Note: RECEIVER must still contain the receiver! 346 jump_cc(Assembler::notEqual, 347 RuntimeAddress(SharedRuntime::get_ic_miss_stub())); 348 const int ic_cmp_size = LP64_ONLY(10) NOT_LP64(9); 349 assert(UseCompressedClassPointers || offset() - start_offset == ic_cmp_size, "check alignment in emit_method_entry"); 350 } 351 352 353 void C1_MacroAssembler::build_frame(int frame_size_in_bytes, int bang_size_in_bytes) { 354 assert(bang_size_in_bytes >= frame_size_in_bytes, "stack bang size incorrect"); 355 // Make sure there is enough stack space for this method's activation. 356 // Note that we do this before doing an enter(). This matches the 357 // ordering of C2's stack overflow check / rsp decrement and allows 358 // the SharedRuntime stack overflow handling to be consistent 359 // between the two compilers. 360 generate_stack_overflow_check(bang_size_in_bytes); 361 362 push(rbp); 363 if (PreserveFramePointer) { 364 mov(rbp, rsp); 365 } 366 #ifdef TIERED 367 // c2 leaves fpu stack dirty. Clean it on entry 368 if (UseSSE < 2 ) { 369 empty_FPU_stack(); 370 } 371 #endif // TIERED 372 decrement(rsp, frame_size_in_bytes); // does not emit code for frame_size == 0 373 } 374 375 376 void C1_MacroAssembler::remove_frame(int frame_size_in_bytes) { 377 increment(rsp, frame_size_in_bytes); // Does not emit code for frame_size == 0 378 pop(rbp); 379 } 380 381 382 void C1_MacroAssembler::unverified_entry(Register receiver, Register ic_klass) { 383 if (C1Breakpoint) int3(); 384 inline_cache_check(receiver, ic_klass); 385 } 386 387 388 void C1_MacroAssembler::verified_entry() { 389 if (C1Breakpoint || VerifyFPU || !UseStackBanging) { 390 // Verified Entry first instruction should be 5 bytes long for correct 391 // patching by patch_verified_entry(). 392 // 393 // C1Breakpoint and VerifyFPU have one byte first instruction. 394 // Also first instruction will be one byte "push(rbp)" if stack banging 395 // code is not generated (see build_frame() above). 396 // For all these cases generate long instruction first. 397 fat_nop(); 398 } 399 if (C1Breakpoint)int3(); 400 // build frame 401 verify_FPU(0, "method_entry"); 402 } 403 404 405 #ifndef PRODUCT 406 407 void C1_MacroAssembler::verify_stack_oop(int stack_offset) { 408 if (!VerifyOops) return; 409 verify_oop_addr(Address(rsp, stack_offset)); 410 } 411 412 void C1_MacroAssembler::verify_not_null_oop(Register r) { 413 if (!VerifyOops) return; 414 Label not_null; 415 testptr(r, r); 416 jcc(Assembler::notZero, not_null); 417 stop("non-null oop required"); 418 bind(not_null); 419 verify_oop(r); 420 } 421 422 void C1_MacroAssembler::invalidate_registers(bool inv_rax, bool inv_rbx, bool inv_rcx, bool inv_rdx, bool inv_rsi, bool inv_rdi) { 423 #ifdef ASSERT 424 if (inv_rax) movptr(rax, 0xDEAD); 425 if (inv_rbx) movptr(rbx, 0xDEAD); 426 if (inv_rcx) movptr(rcx, 0xDEAD); 427 if (inv_rdx) movptr(rdx, 0xDEAD); 428 if (inv_rsi) movptr(rsi, 0xDEAD); 429 if (inv_rdi) movptr(rdi, 0xDEAD); 430 #endif 431 } 432 433 #endif // ifndef PRODUCT