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()), 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 (LockingMode == LM_LIGHTWEIGHT) {
 66 #ifdef _LP64
 67     const Register thread = r15_thread;
 68 #else
 69     const Register thread = disp_hdr;
 70     get_thread(thread);
 71 #endif
 72     lightweight_lock(obj, hdr, thread, tmp, slow_case);
 73   } else  if (LockingMode == LM_LEGACY) {
 74     Label done;


 75     // and mark it as unlocked
 76     orptr(hdr, markWord::unlocked_value);
 77     // save unlocked object header into the displaced header location on the stack
 78     movptr(Address(disp_hdr, 0), hdr);
 79     // test if object header is still the same (i.e. unlocked), and if so, store the
 80     // displaced header address in the object header - if it is not the same, get the
 81     // object header instead
 82     MacroAssembler::lock(); // must be immediately before cmpxchg!
 83     cmpxchgptr(disp_hdr, Address(obj, hdr_offset));
 84     // if the object header was the same, we're done
 85     jcc(Assembler::equal, done);
 86     // if the object header was not the same, it is now in the hdr register
 87     // => test if it is a stack pointer into the same stack (recursive locking), i.e.:
 88     //
 89     // 1) (hdr & aligned_mask) == 0
 90     // 2) rsp <= hdr
 91     // 3) hdr <= rsp + page_size
 92     //
 93     // these 3 tests can be done by evaluating the following expression:
 94     //
 95     // (hdr - rsp) & (aligned_mask - page_size)
 96     //
 97     // assuming both the stack pointer and page_size have their least
 98     // significant 2 bits cleared and page_size is a power of 2
 99     subptr(hdr, rsp);
100     andptr(hdr, aligned_mask - (int)os::vm_page_size());
101     // for recursive locking, the result is zero => save it in the displaced header
102     // location (null in the displaced hdr location indicates recursive locking)
103     movptr(Address(disp_hdr, 0), hdr);
104     // otherwise we don't care about the result and handle locking via runtime call
105     jcc(Assembler::notZero, slow_case);
106     // done
107     bind(done);
108   }
109 
110   inc_held_monitor_count();
111 
112   return null_check_offset;
113 }
114 
115 void C1_MacroAssembler::unlock_object(Register hdr, Register obj, Register disp_hdr, Label& slow_case) {
116   const int aligned_mask = BytesPerWord -1;
117   const int hdr_offset = oopDesc::mark_offset_in_bytes();
118   assert(disp_hdr == rax, "disp_hdr must be rax, for the cmpxchg instruction");
119   assert(hdr != obj && hdr != disp_hdr && obj != disp_hdr, "registers must be different");
120   Label done;
121 
122   if (LockingMode != LM_LIGHTWEIGHT) {
123     // load displaced header
124     movptr(hdr, Address(disp_hdr, 0));
125     // if the loaded hdr is null we had recursive locking
126     testptr(hdr, hdr);
127     // if we had recursive locking, we are done
128     jcc(Assembler::zero, done);
129   }
130 
131   // load object
132   movptr(obj, Address(disp_hdr, BasicObjectLock::obj_offset()));
133   verify_oop(obj);
134 
135   if (LockingMode == LM_LIGHTWEIGHT) {
136     movptr(disp_hdr, Address(obj, hdr_offset));
137     andptr(disp_hdr, ~(int32_t)markWord::lock_mask_in_place);
138     lightweight_unlock(obj, disp_hdr, hdr, slow_case);





139   } else if (LockingMode == LM_LEGACY) {
140     // test if object header is pointing to the displaced header, and if so, restore
141     // the displaced header in the object - if the object header is not pointing to
142     // the displaced header, get the object header instead
143     MacroAssembler::lock(); // must be immediately before cmpxchg!
144     cmpxchgptr(hdr, Address(obj, hdr_offset));
145     // if the object header was not pointing to the displaced header,
146     // we do unlocking via runtime call
147     jcc(Assembler::notEqual, slow_case);
148     // done
149   }
150   bind(done);
151   dec_held_monitor_count();
152 }
153 
154 
155 // Defines obj, preserves var_size_in_bytes
156 void C1_MacroAssembler::try_allocate(Register obj, Register var_size_in_bytes, int con_size_in_bytes, Register t1, Register t2, Label& slow_case) {
157   if (UseTLAB) {
158     tlab_allocate(noreg, obj, var_size_in_bytes, con_size_in_bytes, t1, t2, slow_case);
159   } else {
160     jmp(slow_case);
161   }
162 }
163 
164 
165 void C1_MacroAssembler::initialize_header(Register obj, Register klass, Register len, Register t1, Register t2) {
166   assert_different_registers(obj, klass, len);
167   movptr(Address(obj, oopDesc::mark_offset_in_bytes()), checked_cast<int32_t>(markWord::prototype().value()));
168 #ifdef _LP64
169   if (UseCompressedClassPointers) { // Take care not to kill klass




170     movptr(t1, klass);
171     encode_klass_not_null(t1, rscratch1);
172     movl(Address(obj, oopDesc::klass_offset_in_bytes()), t1);
173   } else
174 #endif
175   {

176     movptr(Address(obj, oopDesc::klass_offset_in_bytes()), klass);
177   }
178 
179   if (len->is_valid()) {
180     movl(Address(obj, arrayOopDesc::length_offset_in_bytes()), len);
181   }
182 #ifdef _LP64
183   else if (UseCompressedClassPointers) {
184     xorptr(t1, t1);
185     store_klass_gap(obj, t1);
186   }
187 #endif
188 }
189 
190 
191 // preserves obj, destroys len_in_bytes
192 void C1_MacroAssembler::initialize_body(Register obj, Register len_in_bytes, int hdr_size_in_bytes, Register t1) {
193   assert(hdr_size_in_bytes >= 0, "header size must be positive or 0");
194   Label done;
195 
196   // len_in_bytes is positive and ptr sized
197   subptr(len_in_bytes, hdr_size_in_bytes);
198   zero_memory(obj, len_in_bytes, hdr_size_in_bytes, t1);
199   bind(done);
200 }
201 
202 
203 void C1_MacroAssembler::allocate_object(Register obj, Register t1, Register t2, int header_size, int object_size, Register klass, Label& slow_case) {
204   assert(obj == rax, "obj must be in rax, for cmpxchg");
205   assert_different_registers(obj, t1, t2); // XXX really?
206   assert(header_size >= 0 && object_size >= header_size, "illegal sizes");
207 
208   try_allocate(obj, noreg, object_size * BytesPerWord, t1, t2, slow_case);
209 
210   initialize_object(obj, klass, noreg, object_size * HeapWordSize, t1, t2, UseTLAB);
211 }
212 
213 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) {
214   assert((con_size_in_bytes & MinObjAlignmentInBytesMask) == 0,
215          "con_size_in_bytes is not multiple of alignment");
216   const int hdr_size_in_bytes = instanceOopDesc::header_size() * HeapWordSize;

217 
218   initialize_header(obj, klass, noreg, t1, t2);
219 
220   if (!(UseTLAB && ZeroTLAB && is_tlab_allocated)) {
221     // clear rest of allocated space
222     const Register t1_zero = t1;
223     const Register index = t2;
224     const int threshold = 6 * BytesPerWord;   // approximate break even point for code size (see comments below)
225     if (var_size_in_bytes != noreg) {
226       mov(index, var_size_in_bytes);
227       initialize_body(obj, index, hdr_size_in_bytes, t1_zero);
228     } else if (con_size_in_bytes <= threshold) {
229       // use explicit null stores
230       // code size = 2 + 3*n bytes (n = number of fields to clear)
231       xorptr(t1_zero, t1_zero); // use t1_zero reg to clear memory (shorter code)
232       for (int i = hdr_size_in_bytes; i < con_size_in_bytes; i += BytesPerWord)
233         movptr(Address(obj, i), t1_zero);
234     } else if (con_size_in_bytes > hdr_size_in_bytes) {
235       // use loop to null out the fields
236       // code size = 16 bytes for even n (n = number of fields to clear)
237       // initialize last object field first if odd number of fields
238       xorptr(t1_zero, t1_zero); // use t1_zero reg to clear memory (shorter code)
239       movptr(index, (con_size_in_bytes - hdr_size_in_bytes) >> 3);
240       // initialize last object field if constant size is odd
241       if (((con_size_in_bytes - hdr_size_in_bytes) & 4) != 0)
242         movptr(Address(obj, con_size_in_bytes - (1*BytesPerWord)), t1_zero);
243       // initialize remaining object fields: rdx is a multiple of 2
244       { Label loop;
245         bind(loop);
246         movptr(Address(obj, index, Address::times_8, hdr_size_in_bytes - (1*BytesPerWord)),
247                t1_zero);
248         NOT_LP64(movptr(Address(obj, index, Address::times_8, hdr_size_in_bytes - (2*BytesPerWord)),
249                t1_zero);)
250         decrement(index);
251         jcc(Assembler::notZero, loop);
252       }
253     }
254   }
255 
256   if (CURRENT_ENV->dtrace_alloc_probes()) {
257     assert(obj == rax, "must be");
258     call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id)));
259   }
260 
261   verify_oop(obj);
262 }
263 
264 void C1_MacroAssembler::allocate_array(Register obj, Register len, Register t1, Register t2, int header_size, Address::ScaleFactor f, Register klass, Label& slow_case) {
265   assert(obj == rax, "obj must be in rax, for cmpxchg");
266   assert_different_registers(obj, len, t1, t2, klass);
267 
268   // determine alignment mask
269   assert(!(BytesPerWord & 1), "must be a multiple of 2 for masking code to work");
270 
271   // check for negative or excessive length
272   cmpptr(len, checked_cast<int32_t>(max_array_allocation_length));
273   jcc(Assembler::above, slow_case);
274 
275   const Register arr_size = t2; // okay to be the same
276   // align object end
277   movptr(arr_size, header_size * BytesPerWord + MinObjAlignmentInBytesMask);
278   lea(arr_size, Address(arr_size, len, f));
279   andptr(arr_size, ~MinObjAlignmentInBytesMask);
280 
281   try_allocate(obj, arr_size, 0, t1, t2, slow_case);
282 
283   initialize_header(obj, klass, len, t1, t2);
284 













285   // clear rest of allocated space
286   const Register len_zero = len;
287   initialize_body(obj, arr_size, header_size * BytesPerWord, len_zero);
288 
289   if (CURRENT_ENV->dtrace_alloc_probes()) {
290     assert(obj == rax, "must be");
291     call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id)));
292   }
293 
294   verify_oop(obj);
295 }
296 
297 
298 
299 void C1_MacroAssembler::inline_cache_check(Register receiver, Register iCache) {
300   verify_oop(receiver);
301   // explicit null check not needed since load from [klass_offset] causes a trap
302   // check against inline cache
303   assert(!MacroAssembler::needs_explicit_null_check(oopDesc::klass_offset_in_bytes()), "must add explicit null check");
304   int start_offset = offset();
305 
306   if (UseCompressedClassPointers) {
307     load_klass(rscratch1, receiver, rscratch2);
308     cmpptr(rscratch1, iCache);
309   } else {
310     cmpptr(iCache, Address(receiver, oopDesc::klass_offset_in_bytes()));
311   }
312   // if icache check fails, then jump to runtime routine
313   // Note: RECEIVER must still contain the receiver!
314   jump_cc(Assembler::notEqual,
315           RuntimeAddress(SharedRuntime::get_ic_miss_stub()));
316   const int ic_cmp_size = LP64_ONLY(10) NOT_LP64(9);
317   assert(UseCompressedClassPointers || offset() - start_offset == ic_cmp_size, "check alignment in emit_method_entry");
318 }
319 
320 
321 void C1_MacroAssembler::build_frame(int frame_size_in_bytes, int bang_size_in_bytes) {
322   assert(bang_size_in_bytes >= frame_size_in_bytes, "stack bang size incorrect");
323   // Make sure there is enough stack space for this method's activation.
324   // Note that we do this before doing an enter(). This matches the
325   // ordering of C2's stack overflow check / rsp decrement and allows
326   // the SharedRuntime stack overflow handling to be consistent
327   // between the two compilers.
328   generate_stack_overflow_check(bang_size_in_bytes);
329 
330   push(rbp);
331   if (PreserveFramePointer) {
332     mov(rbp, rsp);
333   }
334 #if !defined(_LP64) && defined(COMPILER2)
335   if (UseSSE < 2 && !CompilerConfig::is_c1_only_no_jvmci()) {
336     // c2 leaves fpu stack dirty. Clean it on entry
337     empty_FPU_stack();
338   }
339 #endif // !_LP64 && COMPILER2
340   decrement(rsp, frame_size_in_bytes); // does not emit code for frame_size == 0
341 
342   BarrierSetAssembler* bs = BarrierSet::barrier_set()->barrier_set_assembler();
343   // C1 code is not hot enough to micro optimize the nmethod entry barrier with an out-of-line stub
344   bs->nmethod_entry_barrier(this, nullptr /* slow_path */, nullptr /* continuation */);
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::verified_entry(bool breakAtEntry) {
355   if (breakAtEntry || VerifyFPU) {
356     // Verified Entry first instruction should be 5 bytes long for correct
357     // patching by patch_verified_entry().
358     //
359     // Breakpoint and VerifyFPU have one byte first instruction.
360     // Also first instruction will be one byte "push(rbp)" if stack banging
361     // code is not generated (see build_frame() above).
362     // For all these cases generate long instruction first.
363     fat_nop();
364   }
365   if (breakAtEntry) int3();
366   // build frame
367   IA32_ONLY( verify_FPU(0, "method_entry"); )
368 }
369 
370 void C1_MacroAssembler::load_parameter(int offset_in_words, Register reg) {
371   // rbp, + 0: link
372   //     + 1: return address
373   //     + 2: argument with offset 0
374   //     + 3: argument with offset 1
375   //     + 4: ...
376 
377   movptr(reg, Address(rbp, (offset_in_words + 2) * BytesPerWord));
378 }
379 
380 #ifndef PRODUCT
381 
382 void C1_MacroAssembler::verify_stack_oop(int stack_offset) {
383   if (!VerifyOops) return;
384   verify_oop_addr(Address(rsp, stack_offset));
385 }
386 
387 void C1_MacroAssembler::verify_not_null_oop(Register r) {
388   if (!VerifyOops) return;
389   Label not_null;
390   testptr(r, r);
391   jcc(Assembler::notZero, not_null);
392   stop("non-null oop required");
393   bind(not_null);
394   verify_oop(r);
395 }
396 
397 void C1_MacroAssembler::invalidate_registers(bool inv_rax, bool inv_rbx, bool inv_rcx, bool inv_rdx, bool inv_rsi, bool inv_rdi) {
398 #ifdef ASSERT
399   if (inv_rax) movptr(rax, 0xDEAD);
400   if (inv_rbx) movptr(rbx, 0xDEAD);
401   if (inv_rcx) movptr(rcx, 0xDEAD);
402   if (inv_rdx) movptr(rdx, 0xDEAD);
403   if (inv_rsi) movptr(rsi, 0xDEAD);
404   if (inv_rdi) movptr(rdi, 0xDEAD);
405 #endif
406 }
407 
408 #endif // ifndef PRODUCT
--- EOF ---