1 /* 2 * Copyright (c) 1999, 2013, 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/stubRoutines.hpp" 37 38 int C1_MacroAssembler::lock_object(Register hdr, Register obj, Register disp_hdr, Register scratch, Label& slow_case) { 39 const int aligned_mask = BytesPerWord -1; 40 const int hdr_offset = oopDesc::mark_offset_in_bytes(); 41 assert(hdr == rax, "hdr must be rax, for the cmpxchg instruction"); 42 assert(hdr != obj && hdr != disp_hdr && obj != disp_hdr, "registers must be different"); 43 Label done; 44 int null_check_offset = -1; 45 46 verify_oop(obj); 47 48 // save object being locked into the BasicObjectLock 49 movptr(Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes()), obj); 50 51 if (UseBiasedLocking) { 52 assert(scratch != noreg, "should have scratch register at this point"); 53 null_check_offset = biased_locking_enter(disp_hdr, obj, hdr, scratch, false, done, &slow_case); 54 } else { 55 null_check_offset = offset(); 56 } 57 58 // Load object header 59 movptr(hdr, Address(obj, hdr_offset)); 60 // and mark it as unlocked 61 orptr(hdr, markOopDesc::unlocked_value); 62 // save unlocked object header into the displaced header location on the stack 63 movptr(Address(disp_hdr, 0), hdr); 64 // test if object header is still the same (i.e. unlocked), and if so, store the 65 // displaced header address in the object header - if it is not the same, get the 66 // object header instead 67 if (os::is_MP()) MacroAssembler::lock(); // must be immediately before cmpxchg! 68 cmpxchgptr(disp_hdr, Address(obj, hdr_offset)); 69 // if the object header was the same, we're done 70 if (PrintBiasedLockingStatistics) { 71 cond_inc32(Assembler::equal, 72 ExternalAddress((address)BiasedLocking::fast_path_entry_count_addr())); 73 } 74 jcc(Assembler::equal, done); 75 // if the object header was not the same, it is now in the hdr register 76 // => test if it is a stack pointer into the same stack (recursive locking), i.e.: 77 // 78 // 1) (hdr & aligned_mask) == 0 79 // 2) rsp <= hdr 80 // 3) hdr <= rsp + page_size 81 // 82 // these 3 tests can be done by evaluating the following expression: 83 // 84 // (hdr - rsp) & (aligned_mask - page_size) 85 // 86 // assuming both the stack pointer and page_size have their least 87 // significant 2 bits cleared and page_size is a power of 2 88 subptr(hdr, rsp); 89 andptr(hdr, aligned_mask - os::vm_page_size()); 90 // for recursive locking, the result is zero => save it in the displaced header 91 // location (NULL in the displaced hdr location indicates recursive locking) 92 movptr(Address(disp_hdr, 0), hdr); 93 // otherwise we don't care about the result and handle locking via runtime call 94 jcc(Assembler::notZero, slow_case); 95 // done 96 bind(done); 97 return null_check_offset; 98 } 99 100 101 void C1_MacroAssembler::unlock_object(Register hdr, Register obj, Register disp_hdr, Label& slow_case) { 102 const int aligned_mask = BytesPerWord -1; 103 const int hdr_offset = oopDesc::mark_offset_in_bytes(); 104 assert(disp_hdr == rax, "disp_hdr must be rax, for the cmpxchg instruction"); 105 assert(hdr != obj && hdr != disp_hdr && obj != disp_hdr, "registers must be different"); 106 Label done; 107 108 if (UseBiasedLocking) { 109 // load object 110 movptr(obj, Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes())); 111 biased_locking_exit(obj, hdr, done); 112 } 113 114 // load displaced header 115 movptr(hdr, Address(disp_hdr, 0)); 116 // if the loaded hdr is NULL we had recursive locking 117 testptr(hdr, hdr); 118 // if we had recursive locking, we are done 119 jcc(Assembler::zero, done); 120 if (!UseBiasedLocking) { 121 // load object 122 movptr(obj, Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes())); 123 } 124 verify_oop(obj); 125 // test if object header is pointing to the displaced header, and if so, restore 126 // the displaced header in the object - if the object header is not pointing to 127 // the displaced header, get the object header instead 128 if (os::is_MP()) MacroAssembler::lock(); // must be immediately before cmpxchg! 129 cmpxchgptr(hdr, Address(obj, hdr_offset)); 130 // if the object header was not pointing to the displaced header, 131 // we do unlocking via runtime call 132 jcc(Assembler::notEqual, slow_case); 133 // done 134 bind(done); 135 } 136 137 138 // Defines obj, preserves var_size_in_bytes 139 void C1_MacroAssembler::try_allocate(Register obj, Register var_size_in_bytes, int con_size_in_bytes, Register t1, Register t2, Label& slow_case) { 140 if (UseTLAB) { 141 tlab_allocate(obj, var_size_in_bytes, con_size_in_bytes, t1, t2, slow_case); 142 } else { 143 eden_allocate(obj, var_size_in_bytes, con_size_in_bytes, t1, slow_case); 144 incr_allocated_bytes(noreg, var_size_in_bytes, con_size_in_bytes, t1); 145 } 146 } 147 148 149 void C1_MacroAssembler::initialize_header(Register obj, Register klass, Register len, Register t1, Register t2) { 150 assert_different_registers(obj, klass, len); 151 if (UseBiasedLocking && !len->is_valid()) { 152 assert_different_registers(obj, klass, len, t1, t2); 153 movptr(t1, Address(klass, Klass::prototype_header_offset())); 154 movptr(Address(obj, oopDesc::mark_offset_in_bytes()), t1); 155 } else { 156 // This assumes that all prototype bits fit in an int32_t 157 movptr(Address(obj, oopDesc::mark_offset_in_bytes ()), (int32_t)(intptr_t)markOopDesc::prototype()); 158 } 159 #ifdef _LP64 160 if (UseCompressedClassPointers) { // Take care not to kill klass 161 movptr(t1, klass); 162 encode_klass_not_null(t1); 163 movl(Address(obj, oopDesc::klass_offset_in_bytes()), t1); 164 } else 165 #endif 166 { 167 movptr(Address(obj, oopDesc::klass_offset_in_bytes()), klass); 168 } 169 170 if (len->is_valid()) { 171 movl(Address(obj, arrayOopDesc::length_offset_in_bytes()), len); 172 } 173 #ifdef _LP64 174 else if (UseCompressedClassPointers) { 175 xorptr(t1, t1); 176 store_klass_gap(obj, t1); 177 } 178 #endif 179 } 180 181 182 // preserves obj, destroys len_in_bytes 183 void C1_MacroAssembler::initialize_body(Register obj, Register len_in_bytes, int hdr_size_in_bytes, Register t1) { 184 Label done; 185 assert(obj != len_in_bytes && obj != t1 && t1 != len_in_bytes, "registers must be different"); 186 assert((hdr_size_in_bytes & (BytesPerWord - 1)) == 0, "header size is not a multiple of BytesPerWord"); 187 Register index = len_in_bytes; 188 // index is positive and ptr sized 189 subptr(index, hdr_size_in_bytes); 190 jcc(Assembler::zero, done); 191 // initialize topmost word, divide index by 2, check if odd and test if zero 192 // note: for the remaining code to work, index must be a multiple of BytesPerWord 193 #ifdef ASSERT 194 { Label L; 195 testptr(index, BytesPerWord - 1); 196 jcc(Assembler::zero, L); 197 stop("index is not a multiple of BytesPerWord"); 198 bind(L); 199 } 200 #endif 201 xorptr(t1, t1); // use _zero reg to clear memory (shorter code) 202 if (UseIncDec) { 203 shrptr(index, 3); // divide by 8/16 and set carry flag if bit 2 was set 204 } else { 205 shrptr(index, 2); // use 2 instructions to avoid partial flag stall 206 shrptr(index, 1); 207 } 208 #ifndef _LP64 209 // index could have been not a multiple of 8 (i.e., bit 2 was set) 210 { Label even; 211 // note: if index was a multiple of 8, than it cannot 212 // be 0 now otherwise it must have been 0 before 213 // => if it is even, we don't need to check for 0 again 214 jcc(Assembler::carryClear, even); 215 // clear topmost word (no jump needed if conditional assignment would work here) 216 movptr(Address(obj, index, Address::times_8, hdr_size_in_bytes - 0*BytesPerWord), t1); 217 // index could be 0 now, need to check again 218 jcc(Assembler::zero, done); 219 bind(even); 220 } 221 #endif // !_LP64 222 // initialize remaining object fields: rdx is a multiple of 2 now 223 { Label loop; 224 bind(loop); 225 movptr(Address(obj, index, Address::times_8, hdr_size_in_bytes - 1*BytesPerWord), t1); 226 NOT_LP64(movptr(Address(obj, index, Address::times_8, hdr_size_in_bytes - 2*BytesPerWord), t1);) 227 decrement(index); 228 jcc(Assembler::notZero, loop); 229 } 230 231 // done 232 bind(done); 233 } 234 235 236 void C1_MacroAssembler::allocate_object(Register obj, Register t1, Register t2, int header_size, int object_size, Register klass, Label& slow_case) { 237 assert(obj == rax, "obj must be in rax, for cmpxchg"); 238 assert_different_registers(obj, t1, t2); // XXX really? 239 assert(header_size >= 0 && object_size >= header_size, "illegal sizes"); 240 241 try_allocate(obj, noreg, object_size * BytesPerWord, t1, t2, slow_case); 242 243 initialize_object(obj, klass, noreg, object_size * HeapWordSize, t1, t2); 244 } 245 246 void C1_MacroAssembler::initialize_object(Register obj, Register klass, Register var_size_in_bytes, int con_size_in_bytes, Register t1, Register t2) { 247 assert((con_size_in_bytes & MinObjAlignmentInBytesMask) == 0, 248 "con_size_in_bytes is not multiple of alignment"); 249 const int hdr_size_in_bytes = instanceOopDesc::header_size() * HeapWordSize; 250 251 initialize_header(obj, klass, noreg, t1, t2); 252 253 // clear rest of allocated space 254 const Register t1_zero = t1; 255 const Register index = t2; 256 const int threshold = 6 * BytesPerWord; // approximate break even point for code size (see comments below) 257 if (var_size_in_bytes != noreg) { 258 mov(index, var_size_in_bytes); 259 initialize_body(obj, index, hdr_size_in_bytes, t1_zero); 260 } else if (con_size_in_bytes <= threshold) { 261 // use explicit null stores 262 // code size = 2 + 3*n bytes (n = number of fields to clear) 263 xorptr(t1_zero, t1_zero); // use t1_zero reg to clear memory (shorter code) 264 for (int i = hdr_size_in_bytes; i < con_size_in_bytes; i += BytesPerWord) 265 movptr(Address(obj, i), t1_zero); 266 } else if (con_size_in_bytes > hdr_size_in_bytes) { 267 // use loop to null out the fields 268 // code size = 16 bytes for even n (n = number of fields to clear) 269 // initialize last object field first if odd number of fields 270 xorptr(t1_zero, t1_zero); // use t1_zero reg to clear memory (shorter code) 271 movptr(index, (con_size_in_bytes - hdr_size_in_bytes) >> 3); 272 // initialize last object field if constant size is odd 273 if (((con_size_in_bytes - hdr_size_in_bytes) & 4) != 0) 274 movptr(Address(obj, con_size_in_bytes - (1*BytesPerWord)), t1_zero); 275 // initialize remaining object fields: rdx is a multiple of 2 276 { Label loop; 277 bind(loop); 278 movptr(Address(obj, index, Address::times_8, hdr_size_in_bytes - (1*BytesPerWord)), 279 t1_zero); 280 NOT_LP64(movptr(Address(obj, index, Address::times_8, hdr_size_in_bytes - (2*BytesPerWord)), 281 t1_zero);) 282 decrement(index); 283 jcc(Assembler::notZero, loop); 284 } 285 } 286 287 if (CURRENT_ENV->dtrace_alloc_probes()) { 288 assert(obj == rax, "must be"); 289 call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id))); 290 } 291 292 verify_oop(obj); 293 } 294 295 void C1_MacroAssembler::allocate_array(Register obj, Register len, Register t1, Register t2, int header_size, Address::ScaleFactor f, Register klass, Label& slow_case) { 296 assert(obj == rax, "obj must be in rax, for cmpxchg"); 297 assert_different_registers(obj, len, t1, t2, klass); 298 299 // determine alignment mask 300 assert(!(BytesPerWord & 1), "must be a multiple of 2 for masking code to work"); 301 302 // check for negative or excessive length 303 cmpptr(len, (int32_t)max_array_allocation_length); 304 jcc(Assembler::above, slow_case); 305 306 const Register arr_size = t2; // okay to be the same 307 // align object end 308 movptr(arr_size, (int32_t)header_size * BytesPerWord + MinObjAlignmentInBytesMask); 309 lea(arr_size, Address(arr_size, len, f)); 310 andptr(arr_size, ~MinObjAlignmentInBytesMask); 311 312 try_allocate(obj, arr_size, 0, t1, t2, slow_case); 313 314 initialize_header(obj, klass, len, t1, t2); 315 316 // clear rest of allocated space 317 const Register len_zero = len; 318 initialize_body(obj, arr_size, header_size * BytesPerWord, len_zero); 319 320 if (CURRENT_ENV->dtrace_alloc_probes()) { 321 assert(obj == rax, "must be"); 322 call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id))); 323 } 324 325 verify_oop(obj); 326 } 327 328 329 330 void C1_MacroAssembler::inline_cache_check(Register receiver, Register iCache) { 331 verify_oop(receiver); 332 // explicit NULL check not needed since load from [klass_offset] causes a trap 333 // check against inline cache 334 assert(!MacroAssembler::needs_explicit_null_check(oopDesc::klass_offset_in_bytes()), "must add explicit null check"); 335 int start_offset = offset(); 336 337 if (UseCompressedClassPointers) { 338 load_klass(rscratch1, receiver); 339 cmpptr(rscratch1, iCache); 340 } else { 341 cmpptr(iCache, Address(receiver, oopDesc::klass_offset_in_bytes())); 342 } 343 // if icache check fails, then jump to runtime routine 344 // Note: RECEIVER must still contain the receiver! 345 jump_cc(Assembler::notEqual, 346 RuntimeAddress(SharedRuntime::get_ic_miss_stub())); 347 const int ic_cmp_size = LP64_ONLY(10) NOT_LP64(9); 348 assert(UseCompressedClassPointers || offset() - start_offset == ic_cmp_size, "check alignment in emit_method_entry"); 349 } 350 351 352 void C1_MacroAssembler::build_frame(int frame_size_in_bytes) { 353 // Make sure there is enough stack space for this method's activation. 354 // Note that we do this before doing an enter(). This matches the 355 // ordering of C2's stack overflow check / rsp decrement and allows 356 // the SharedRuntime stack overflow handling to be consistent 357 // between the two compilers. 358 generate_stack_overflow_check(frame_size_in_bytes); 359 360 push(rbp); 361 #ifdef TIERED 362 // c2 leaves fpu stack dirty. Clean it on entry 363 if (UseSSE < 2 ) { 364 empty_FPU_stack(); 365 } 366 #endif // TIERED 367 decrement(rsp, frame_size_in_bytes); // does not emit code for frame_size == 0 368 } 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::unverified_entry(Register receiver, Register ic_klass) { 378 if (C1Breakpoint) int3(); 379 inline_cache_check(receiver, ic_klass); 380 } 381 382 383 void C1_MacroAssembler::verified_entry() { 384 if (C1Breakpoint || VerifyFPU || !UseStackBanging) { 385 // Verified Entry first instruction should be 5 bytes long for correct 386 // patching by patch_verified_entry(). 387 // 388 // C1Breakpoint and VerifyFPU have one byte first instruction. 389 // Also first instruction will be one byte "push(rbp)" if stack banging 390 // code is not generated (see build_frame() above). 391 // For all these cases generate long instruction first. 392 fat_nop(); 393 } 394 if (C1Breakpoint)int3(); 395 // build frame 396 verify_FPU(0, "method_entry"); 397 } 398 399 400 #ifndef PRODUCT 401 402 void C1_MacroAssembler::verify_stack_oop(int stack_offset) { 403 if (!VerifyOops) return; 404 verify_oop_addr(Address(rsp, stack_offset)); 405 } 406 407 void C1_MacroAssembler::verify_not_null_oop(Register r) { 408 if (!VerifyOops) return; 409 Label not_null; 410 testptr(r, r); 411 jcc(Assembler::notZero, not_null); 412 stop("non-null oop required"); 413 bind(not_null); 414 verify_oop(r); 415 } 416 417 void C1_MacroAssembler::invalidate_registers(bool inv_rax, bool inv_rbx, bool inv_rcx, bool inv_rdx, bool inv_rsi, bool inv_rdi) { 418 #ifdef ASSERT 419 if (inv_rax) movptr(rax, 0xDEAD); 420 if (inv_rbx) movptr(rbx, 0xDEAD); 421 if (inv_rcx) movptr(rcx, 0xDEAD); 422 if (inv_rdx) movptr(rdx, 0xDEAD); 423 if (inv_rsi) movptr(rsi, 0xDEAD); 424 if (inv_rdi) movptr(rdi, 0xDEAD); 425 #endif 426 } 427 428 #endif // ifndef PRODUCT