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 "assembler_x86.hpp" 27 #include "c1/c1_MacroAssembler.hpp" 28 #include "c1/c1_Runtime1.hpp" 29 #include "classfile/systemDictionary.hpp" 30 #include "gc/shared/collectedHeap.hpp" 31 #include "interpreter/interpreter.hpp" 32 #include "oops/arrayOop.hpp" 33 #include "oops/markOop.hpp" 34 #include "runtime/basicLock.hpp" 35 #include "runtime/biasedLocking.hpp" 36 #include "runtime/os.hpp" 37 #include "runtime/sharedRuntime.hpp" 38 #include "runtime/stubRoutines.hpp" 39 40 int C1_MacroAssembler::lock_object(Register hdr, Register obj, Register disp_hdr, Register scratch, Label& slow_case) { 41 const int aligned_mask = BytesPerWord -1; 42 const int hdr_offset = oopDesc::mark_offset_in_bytes(); 43 assert(hdr == rax, "hdr must be rax, for the cmpxchg instruction"); 44 assert(hdr != obj && hdr != disp_hdr && obj != disp_hdr, "registers must be different"); 45 Label done; 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 if (UseBiasedLocking) { 54 assert(scratch != noreg, "should have scratch register at this point"); 55 null_check_offset = biased_locking_enter(disp_hdr, obj, hdr, scratch, false, done, &slow_case); 56 } else { 57 null_check_offset = offset(); 58 } 59 60 // Load object header 61 movptr(hdr, Address(obj, hdr_offset)); 62 // and mark it as unlocked 63 orptr(hdr, markOopDesc::unlocked_value); 64 // save unlocked object header into the displaced header location on the stack 65 movptr(Address(disp_hdr, 0), hdr); 66 // test if object header is still the same (i.e. unlocked), and if so, store the 67 // displaced header address in the object header - if it is not the same, get the 68 // object header instead 69 if (os::is_MP()) MacroAssembler::lock(); // must be immediately before cmpxchg! 70 cmpxchgptr(disp_hdr, Address(obj, hdr_offset)); 71 // if the object header was the same, we're done 72 if (PrintBiasedLockingStatistics) { 73 cond_inc32(Assembler::equal, 74 ExternalAddress((address)BiasedLocking::fast_path_entry_count_addr())); 75 } 76 jcc(Assembler::equal, done); 77 // if the object header was not the same, it is now in the hdr register 78 // => test if it is a stack pointer into the same stack (recursive locking), i.e.: 79 // 80 // 1) (hdr & aligned_mask) == 0 81 // 2) rsp <= hdr 82 // 3) hdr <= rsp + page_size 83 // 84 // these 3 tests can be done by evaluating the following expression: 85 // 86 // (hdr - rsp) & (aligned_mask - page_size) 87 // 88 // assuming both the stack pointer and page_size have their least 89 // significant 2 bits cleared and page_size is a power of 2 90 subptr(hdr, rsp); 91 andptr(hdr, aligned_mask - os::vm_page_size()); 92 // for recursive locking, the result is zero => save it in the displaced header 93 // location (NULL in the displaced hdr location indicates recursive locking) 94 movptr(Address(disp_hdr, 0), hdr); 95 // otherwise we don't care about the result and handle locking via runtime call 96 jcc(Assembler::notZero, slow_case); 97 // done 98 bind(done); 99 return null_check_offset; 100 } 101 102 103 void C1_MacroAssembler::unlock_object(Register hdr, Register obj, Register disp_hdr, Label& slow_case) { 104 const int aligned_mask = BytesPerWord -1; 105 const int hdr_offset = oopDesc::mark_offset_in_bytes(); 106 assert(disp_hdr == rax, "disp_hdr must be rax, for the cmpxchg instruction"); 107 assert(hdr != obj && hdr != disp_hdr && obj != disp_hdr, "registers must be different"); 108 Label done; 109 110 if (UseBiasedLocking) { 111 // load object 112 movptr(obj, Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes())); 113 biased_locking_exit(obj, hdr, done); 114 } 115 116 // load displaced header 117 movptr(hdr, Address(disp_hdr, 0)); 118 // if the loaded hdr is NULL we had recursive locking 119 testptr(hdr, hdr); 120 // if we had recursive locking, we are done 121 jcc(Assembler::zero, done); 122 if (!UseBiasedLocking) { 123 // load object 124 movptr(obj, Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes())); 125 } 126 verify_oop(obj); 127 // test if object header is pointing to the displaced header, and if so, restore 128 // the displaced header in the object - if the object header is not pointing to 129 // the displaced header, get the object header instead 130 if (os::is_MP()) MacroAssembler::lock(); // must be immediately before cmpxchg! 131 cmpxchgptr(hdr, Address(obj, hdr_offset)); 132 // if the object header was not pointing to the displaced header, 133 // we do unlocking via runtime call 134 jcc(Assembler::notEqual, slow_case); 135 // done 136 bind(done); 137 } 138 139 140 // Defines obj, preserves var_size_in_bytes 141 void C1_MacroAssembler::try_allocate(Register obj, Register var_size_in_bytes, int con_size_in_bytes, Register t1, Register t2, Label& slow_case) { 142 if (UseTLAB) { 143 tlab_allocate(obj, var_size_in_bytes, con_size_in_bytes, t1, t2, slow_case); 144 } else { 145 eden_allocate(obj, var_size_in_bytes, con_size_in_bytes, t1, slow_case); 146 incr_allocated_bytes(noreg, var_size_in_bytes, con_size_in_bytes, t1); 147 } 148 } 149 150 151 void C1_MacroAssembler::initialize_header(Register obj, Register klass, Register len, Register t1, Register t2) { 152 assert_different_registers(obj, klass, len); 153 if (UseBiasedLocking && !len->is_valid()) { 154 assert_different_registers(obj, klass, len, t1, t2); 155 movptr(t1, Address(klass, Klass::prototype_header_offset())); 156 movptr(Address(obj, oopDesc::mark_offset_in_bytes()), t1); 157 } else { 158 // This assumes that all prototype bits fit in an int32_t 159 movptr(Address(obj, oopDesc::mark_offset_in_bytes ()), (int32_t)(intptr_t)markOopDesc::prototype()); 160 } 161 #ifdef _LP64 162 if (UseCompressedClassPointers) { // Take care not to kill klass 163 movptr(t1, klass); 164 encode_klass_not_null(t1); 165 movl(Address(obj, oopDesc::klass_offset_in_bytes()), t1); 166 } else 167 #endif 168 { 169 movptr(Address(obj, oopDesc::klass_offset_in_bytes()), klass); 170 } 171 172 if (len->is_valid()) { 173 movl(Address(obj, arrayOopDesc::length_offset_in_bytes()), len); 174 } 175 #ifdef _LP64 176 else if (UseCompressedClassPointers) { 177 xorptr(t1, t1); 178 store_klass_gap(obj, t1); 179 } 180 #endif 181 } 182 183 184 // preserves obj, destroys len_in_bytes 185 void C1_MacroAssembler::initialize_body(Register obj, Register len_in_bytes, int hdr_size_in_bytes, Register t1) { 186 assert(hdr_size_in_bytes >= 0, "header size must be positive or 0"); 187 Label done; 188 189 // len_in_bytes is positive and ptr sized 190 subptr(len_in_bytes, hdr_size_in_bytes); 191 jcc(Assembler::zero, done); 192 zero_memory(obj, len_in_bytes, hdr_size_in_bytes, t1); 193 bind(done); 194 } 195 196 197 void C1_MacroAssembler::allocate_object(Register obj, Register t1, Register t2, int header_size, int object_size, Register klass, Label& slow_case) { 198 assert(obj == rax, "obj must be in rax, for cmpxchg"); 199 assert_different_registers(obj, t1, t2); // XXX really? 200 assert(header_size >= 0 && object_size >= header_size, "illegal sizes"); 201 202 try_allocate(obj, noreg, object_size * BytesPerWord, t1, t2, slow_case); 203 204 initialize_object(obj, klass, noreg, object_size * HeapWordSize, t1, t2, UseTLAB); 205 206 HEAP_MONITORING(this, noreg, noreg, object_size * HeapWordSize, obj, 207 t1, t2, call(RuntimeAddress(Runtime1::entry_for( 208 Runtime1::heap_object_sample_id)));); 209 } 210 211 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) { 212 assert((con_size_in_bytes & MinObjAlignmentInBytesMask) == 0, 213 "con_size_in_bytes is not multiple of alignment"); 214 const int hdr_size_in_bytes = instanceOopDesc::header_size() * HeapWordSize; 215 216 initialize_header(obj, klass, noreg, t1, t2); 217 218 if (!(UseTLAB && ZeroTLAB && is_tlab_allocated)) { 219 // clear rest of allocated space 220 const Register t1_zero = t1; 221 const Register index = t2; 222 const int threshold = 6 * BytesPerWord; // approximate break even point for code size (see comments below) 223 if (var_size_in_bytes != noreg) { 224 mov(index, var_size_in_bytes); 225 initialize_body(obj, index, hdr_size_in_bytes, t1_zero); 226 } else if (con_size_in_bytes <= threshold) { 227 // use explicit null stores 228 // code size = 2 + 3*n bytes (n = number of fields to clear) 229 xorptr(t1_zero, t1_zero); // use t1_zero reg to clear memory (shorter code) 230 for (int i = hdr_size_in_bytes; i < con_size_in_bytes; i += BytesPerWord) 231 movptr(Address(obj, i), t1_zero); 232 } else if (con_size_in_bytes > hdr_size_in_bytes) { 233 // use loop to null out the fields 234 // code size = 16 bytes for even n (n = number of fields to clear) 235 // initialize last object field first if odd number of fields 236 xorptr(t1_zero, t1_zero); // use t1_zero reg to clear memory (shorter code) 237 movptr(index, (con_size_in_bytes - hdr_size_in_bytes) >> 3); 238 // initialize last object field if constant size is odd 239 if (((con_size_in_bytes - hdr_size_in_bytes) & 4) != 0) 240 movptr(Address(obj, con_size_in_bytes - (1*BytesPerWord)), t1_zero); 241 // initialize remaining object fields: rdx is a multiple of 2 242 { Label loop; 243 bind(loop); 244 movptr(Address(obj, index, Address::times_8, hdr_size_in_bytes - (1*BytesPerWord)), 245 t1_zero); 246 NOT_LP64(movptr(Address(obj, index, Address::times_8, hdr_size_in_bytes - (2*BytesPerWord)), 247 t1_zero);) 248 decrement(index); 249 jcc(Assembler::notZero, loop); 250 } 251 } 252 } 253 254 if (CURRENT_ENV->dtrace_alloc_probes()) { 255 assert(obj == rax, "must be"); 256 call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id))); 257 } 258 259 verify_oop(obj); 260 } 261 262 void C1_MacroAssembler::allocate_array(Register obj, Register len, Register t1, Register t2, int header_size, Address::ScaleFactor f, Register klass, Label& slow_case) { 263 assert(obj == rax, "obj must be in rax, for cmpxchg"); 264 assert_different_registers(obj, len, t1, t2, klass); 265 266 // determine alignment mask 267 assert(!(BytesPerWord & 1), "must be a multiple of 2 for masking code to work"); 268 269 // check for negative or excessive length 270 cmpptr(len, (int32_t)max_array_allocation_length); 271 jcc(Assembler::above, slow_case); 272 273 const Register arr_size = t2; // okay to be the same 274 // align object end 275 movptr(arr_size, (int32_t)header_size * BytesPerWord + MinObjAlignmentInBytesMask); 276 lea(arr_size, Address(arr_size, len, f)); 277 andptr(arr_size, ~MinObjAlignmentInBytesMask); 278 279 try_allocate(obj, arr_size, 0, t1, t2, slow_case); 280 281 initialize_header(obj, klass, len, t1, t2); 282 283 // clear rest of allocated space 284 const Register len_zero = len; 285 // Initialize body destroys arr_size so remember it. 286 push(arr_size); 287 initialize_body(obj, arr_size, header_size * BytesPerWord, len_zero); 288 pop(arr_size); 289 290 if (CURRENT_ENV->dtrace_alloc_probes()) { 291 assert(obj == rax, "must be"); 292 call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id))); 293 } 294 295 HEAP_MONITORING(this, noreg, arr_size, 0, obj, t1, noreg, 296 call(RuntimeAddress(Runtime1::entry_for( 297 Runtime1::heap_object_sample_id)));); 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); 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) { 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 #ifdef TIERED 339 // c2 leaves fpu stack dirty. Clean it on entry 340 if (UseSSE < 2 ) { 341 empty_FPU_stack(); 342 } 343 #endif // TIERED 344 decrement(rsp, frame_size_in_bytes); // does not emit code for frame_size == 0 345 } 346 347 348 void C1_MacroAssembler::remove_frame(int frame_size_in_bytes) { 349 increment(rsp, frame_size_in_bytes); // Does not emit code for frame_size == 0 350 pop(rbp); 351 } 352 353 354 void C1_MacroAssembler::unverified_entry(Register receiver, Register ic_klass) { 355 if (C1Breakpoint) int3(); 356 inline_cache_check(receiver, ic_klass); 357 } 358 359 360 void C1_MacroAssembler::verified_entry() { 361 if (C1Breakpoint || VerifyFPU || !UseStackBanging) { 362 // Verified Entry first instruction should be 5 bytes long for correct 363 // patching by patch_verified_entry(). 364 // 365 // C1Breakpoint and VerifyFPU have one byte first instruction. 366 // Also first instruction will be one byte "push(rbp)" if stack banging 367 // code is not generated (see build_frame() above). 368 // For all these cases generate long instruction first. 369 fat_nop(); 370 } 371 if (C1Breakpoint)int3(); 372 // build frame 373 verify_FPU(0, "method_entry"); 374 } 375 376 377 #ifndef PRODUCT 378 379 void C1_MacroAssembler::verify_stack_oop(int stack_offset) { 380 if (!VerifyOops) return; 381 verify_oop_addr(Address(rsp, stack_offset)); 382 } 383 384 void C1_MacroAssembler::verify_not_null_oop(Register r) { 385 if (!VerifyOops) return; 386 Label not_null; 387 testptr(r, r); 388 jcc(Assembler::notZero, not_null); 389 stop("non-null oop required"); 390 bind(not_null); 391 verify_oop(r); 392 } 393 394 void C1_MacroAssembler::invalidate_registers(bool inv_rax, bool inv_rbx, bool inv_rcx, bool inv_rdx, bool inv_rsi, bool inv_rdi) { 395 #ifdef ASSERT 396 if (inv_rax) movptr(rax, 0xDEAD); 397 if (inv_rbx) movptr(rbx, 0xDEAD); 398 if (inv_rcx) movptr(rcx, 0xDEAD); 399 if (inv_rdx) movptr(rdx, 0xDEAD); 400 if (inv_rsi) movptr(rsi, 0xDEAD); 401 if (inv_rdi) movptr(rdi, 0xDEAD); 402 #endif 403 } 404 405 #endif // ifndef PRODUCT