1 /*
  2  * Copyright (c) 1999, 2022, 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/frame.inline.hpp"
 38 #include "runtime/os.hpp"
 39 #include "runtime/sharedRuntime.hpp"
 40 #include "runtime/stubRoutines.hpp"
 41 
 42 int C1_MacroAssembler::lock_object(Register hdr, Register obj, Register disp_hdr, Label& slow_case) {
 43   const int aligned_mask = BytesPerWord -1;
 44   const int hdr_offset = oopDesc::mark_offset_in_bytes();
 45   assert(hdr == rax, "hdr must be rax, for the cmpxchg instruction");
 46   assert(hdr != obj && hdr != disp_hdr && obj != disp_hdr, "registers must be different");
 47   Label done;
 48   int null_check_offset = -1;
 49 
 50   verify_oop(obj);
 51 
 52   // save object being locked into the BasicObjectLock
 53   movptr(Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes()), obj);
 54 
 55   null_check_offset = offset();
 56 
 57   if (DiagnoseSyncOnValueBasedClasses != 0) {
 58     load_klass(hdr, obj, rscratch1);
 59     movl(hdr, Address(hdr, Klass::access_flags_offset()));
 60     testl(hdr, JVM_ACC_IS_VALUE_BASED_CLASS);
 61     jcc(Assembler::notZero, slow_case);
 62   }
 63 
 64   // Load object header
 65   movptr(hdr, Address(obj, hdr_offset));
 66   // and mark it as unlocked
 67   orptr(hdr, markWord::unlocked_value);
 68   if (EnableValhalla) {
 69     // Mask inline_type bit such that we go to the slow path if object is an inline type
 70     andptr(hdr, ~((int) markWord::inline_type_bit_in_place));
 71   }
 72   // save unlocked object header into the displaced header location on the stack
 73   movptr(Address(disp_hdr, 0), hdr);
 74   // test if object header is still the same (i.e. unlocked), and if so, store the
 75   // displaced header address in the object header - if it is not the same, get the
 76   // object header instead
 77   MacroAssembler::lock(); // must be immediately before cmpxchg!
 78   cmpxchgptr(disp_hdr, Address(obj, hdr_offset));
 79   // if the object header was the same, we're done
 80   jcc(Assembler::equal, done);
 81   // if the object header was not the same, it is now in the hdr register
 82   // => test if it is a stack pointer into the same stack (recursive locking), i.e.:
 83   //
 84   // 1) (hdr & aligned_mask) == 0
 85   // 2) rsp <= hdr
 86   // 3) hdr <= rsp + page_size
 87   //
 88   // these 3 tests can be done by evaluating the following expression:
 89   //
 90   // (hdr - rsp) & (aligned_mask - page_size)
 91   //
 92   // assuming both the stack pointer and page_size have their least
 93   // significant 2 bits cleared and page_size is a power of 2
 94   subptr(hdr, rsp);
 95   andptr(hdr, aligned_mask - os::vm_page_size());
 96   // for recursive locking, the result is zero => save it in the displaced header
 97   // location (NULL in the displaced hdr location indicates recursive locking)
 98   movptr(Address(disp_hdr, 0), hdr);
 99   // otherwise we don't care about the result and handle locking via runtime call
100   jcc(Assembler::notZero, slow_case);
101   // done
102   bind(done);
103 
104   inc_held_monitor_count();
105 
106   return null_check_offset;
107 }
108 
109 void C1_MacroAssembler::unlock_object(Register hdr, Register obj, Register disp_hdr, Label& slow_case) {
110   const int aligned_mask = BytesPerWord -1;
111   const int hdr_offset = oopDesc::mark_offset_in_bytes();
112   assert(disp_hdr == rax, "disp_hdr must be rax, for the cmpxchg instruction");
113   assert(hdr != obj && hdr != disp_hdr && obj != disp_hdr, "registers must be different");
114   Label done;
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   // 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   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   dec_held_monitor_count();
138 }
139 
140 
141 // Defines obj, preserves var_size_in_bytes
142 void C1_MacroAssembler::try_allocate(Register obj, Register var_size_in_bytes, int con_size_in_bytes, Register t1, Register t2, Label& slow_case) {
143   if (UseTLAB) {
144     tlab_allocate(noreg, obj, var_size_in_bytes, con_size_in_bytes, t1, t2, slow_case);
145   } else {
146     jmp(slow_case);
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 (EnableValhalla) {
154     // Need to copy markWord::prototype header for klass
155     assert_different_registers(obj, klass, len, t1, t2);
156     movptr(t1, Address(klass, Klass::prototype_header_offset()));
157     movptr(Address(obj, oopDesc::mark_offset_in_bytes()), t1);
158   } else {
159     // This assumes that all prototype bits fit in an int32_t
160     movptr(Address(obj, oopDesc::mark_offset_in_bytes()), checked_cast<int32_t>(markWord::prototype().value()));
161   }
162 #ifdef _LP64
163   if (UseCompressedClassPointers) { // Take care not to kill klass
164     movptr(t1, klass);
165     encode_klass_not_null(t1, rscratch1);
166     movl(Address(obj, oopDesc::klass_offset_in_bytes()), t1);
167   } else
168 #endif
169   {
170     movptr(Address(obj, oopDesc::klass_offset_in_bytes()), klass);
171   }
172 
173   if (len->is_valid()) {
174     movl(Address(obj, arrayOopDesc::length_offset_in_bytes()), len);
175   }
176 #ifdef _LP64
177   else if (UseCompressedClassPointers) {
178     xorptr(t1, t1);
179     store_klass_gap(obj, t1);
180   }
181 #endif
182 }
183 
184 
185 // preserves obj, destroys len_in_bytes
186 void C1_MacroAssembler::initialize_body(Register obj, Register len_in_bytes, int hdr_size_in_bytes, Register t1) {
187   assert(hdr_size_in_bytes >= 0, "header size must be positive or 0");
188   Label done;
189 
190   // len_in_bytes is positive and ptr sized
191   subptr(len_in_bytes, hdr_size_in_bytes);
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 
207 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) {
208   assert((con_size_in_bytes & MinObjAlignmentInBytesMask) == 0,
209          "con_size_in_bytes is not multiple of alignment");
210   const int hdr_size_in_bytes = instanceOopDesc::header_size() * HeapWordSize;
211 
212   initialize_header(obj, klass, noreg, t1, t2);
213 
214   if (!(UseTLAB && ZeroTLAB && is_tlab_allocated)) {
215     // clear rest of allocated space
216     const Register t1_zero = t1;
217     const Register index = t2;
218     const int threshold = 6 * BytesPerWord;   // approximate break even point for code size (see comments below)
219     if (var_size_in_bytes != noreg) {
220       mov(index, var_size_in_bytes);
221       initialize_body(obj, index, hdr_size_in_bytes, t1_zero);
222     } else if (con_size_in_bytes <= threshold) {
223       // use explicit null stores
224       // code size = 2 + 3*n bytes (n = number of fields to clear)
225       xorptr(t1_zero, t1_zero); // use t1_zero reg to clear memory (shorter code)
226       for (int i = hdr_size_in_bytes; i < con_size_in_bytes; i += BytesPerWord)
227         movptr(Address(obj, i), t1_zero);
228     } else if (con_size_in_bytes > hdr_size_in_bytes) {
229       // use loop to null out the fields
230       // code size = 16 bytes for even n (n = number of fields to clear)
231       // initialize last object field first if odd number of fields
232       xorptr(t1_zero, t1_zero); // use t1_zero reg to clear memory (shorter code)
233       movptr(index, (con_size_in_bytes - hdr_size_in_bytes) >> 3);
234       // initialize last object field if constant size is odd
235       if (((con_size_in_bytes - hdr_size_in_bytes) & 4) != 0)
236         movptr(Address(obj, con_size_in_bytes - (1*BytesPerWord)), t1_zero);
237       // initialize remaining object fields: rdx is a multiple of 2
238       { Label loop;
239         bind(loop);
240         movptr(Address(obj, index, Address::times_8, hdr_size_in_bytes - (1*BytesPerWord)),
241                t1_zero);
242         NOT_LP64(movptr(Address(obj, index, Address::times_8, hdr_size_in_bytes - (2*BytesPerWord)),
243                t1_zero);)
244         decrement(index);
245         jcc(Assembler::notZero, loop);
246       }
247     }
248   }
249 
250   if (CURRENT_ENV->dtrace_alloc_probes()) {
251     assert(obj == rax, "must be");
252     call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id)));
253   }
254 
255   verify_oop(obj);
256 }
257 
258 void C1_MacroAssembler::allocate_array(Register obj, Register len, Register t1, Register t2, int header_size, Address::ScaleFactor f, Register klass, Label& slow_case) {
259   assert(obj == rax, "obj must be in rax, for cmpxchg");
260   assert_different_registers(obj, len, t1, t2, klass);
261 
262   // determine alignment mask
263   assert(!(BytesPerWord & 1), "must be a multiple of 2 for masking code to work");
264 
265   // check for negative or excessive length
266   cmpptr(len, checked_cast<int32_t>(max_array_allocation_length));
267   jcc(Assembler::above, slow_case);
268 
269   const Register arr_size = t2; // okay to be the same
270   // align object end
271   movptr(arr_size, header_size * BytesPerWord + MinObjAlignmentInBytesMask);
272   lea(arr_size, Address(arr_size, len, f));
273   andptr(arr_size, ~MinObjAlignmentInBytesMask);
274 
275   try_allocate(obj, arr_size, 0, t1, t2, slow_case);
276 
277   initialize_header(obj, klass, len, t1, t2);
278 
279   // clear rest of allocated space
280   const Register len_zero = len;
281   initialize_body(obj, arr_size, header_size * BytesPerWord, len_zero);
282 
283   if (CURRENT_ENV->dtrace_alloc_probes()) {
284     assert(obj == rax, "must be");
285     call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id)));
286   }
287 
288   verify_oop(obj);
289 }
290 
291 
292 
293 void C1_MacroAssembler::inline_cache_check(Register receiver, Register iCache) {
294   verify_oop(receiver);
295   // explicit NULL check not needed since load from [klass_offset] causes a trap
296   // check against inline cache
297   assert(!MacroAssembler::needs_explicit_null_check(oopDesc::klass_offset_in_bytes()), "must add explicit null check");
298   int start_offset = offset();
299 
300   if (UseCompressedClassPointers) {
301     load_klass(rscratch1, receiver, rscratch2);
302     cmpptr(rscratch1, iCache);
303   } else {
304     cmpptr(iCache, Address(receiver, oopDesc::klass_offset_in_bytes()));
305   }
306   // if icache check fails, then jump to runtime routine
307   // Note: RECEIVER must still contain the receiver!
308   jump_cc(Assembler::notEqual,
309           RuntimeAddress(SharedRuntime::get_ic_miss_stub()));
310   const int ic_cmp_size = LP64_ONLY(10) NOT_LP64(9);
311   assert(UseCompressedClassPointers || offset() - start_offset == ic_cmp_size, "check alignment in emit_method_entry");
312 }
313 
314 void C1_MacroAssembler::build_frame_helper(int frame_size_in_bytes, int sp_offset_for_orig_pc, int sp_inc, bool reset_orig_pc, bool needs_stack_repair) {
315   push(rbp);
316   if (PreserveFramePointer) {
317     mov(rbp, rsp);
318   }
319 #if !defined(_LP64) && defined(COMPILER2)
320   if (UseSSE < 2 && !CompilerConfig::is_c1_only_no_jvmci()) {
321       // c2 leaves fpu stack dirty. Clean it on entry
322       empty_FPU_stack();
323     }
324 #endif // !_LP64 && COMPILER2
325   decrement(rsp, frame_size_in_bytes);
326 
327   if (needs_stack_repair) {
328     // Save stack increment (also account for fixed framesize and rbp)
329     assert((sp_inc & (StackAlignmentInBytes-1)) == 0, "stack increment not aligned");
330     int real_frame_size = sp_inc + frame_size_in_bytes + wordSize;
331     movptr(Address(rsp, frame_size_in_bytes - wordSize), real_frame_size);
332   }
333   if (reset_orig_pc) {
334     // Zero orig_pc to detect deoptimization during buffering in the entry points
335     movptr(Address(rsp, sp_offset_for_orig_pc), 0);
336   }
337 }
338 
339 void C1_MacroAssembler::build_frame(int frame_size_in_bytes, int bang_size_in_bytes, int sp_offset_for_orig_pc, bool needs_stack_repair, bool has_scalarized_args, Label* verified_inline_entry_label) {
340   // Make sure there is enough stack space for this method's activation.
341   // Note that we do this before doing an enter(). This matches the
342   // ordering of C2's stack overflow check / rsp decrement and allows
343   // the SharedRuntime stack overflow handling to be consistent
344   // between the two compilers.
345   assert(bang_size_in_bytes >= frame_size_in_bytes, "stack bang size incorrect");
346   generate_stack_overflow_check(bang_size_in_bytes);
347 
348   build_frame_helper(frame_size_in_bytes, sp_offset_for_orig_pc, 0, has_scalarized_args, needs_stack_repair);
349 
350   BarrierSetAssembler* bs = BarrierSet::barrier_set()->barrier_set_assembler();
351   // C1 code is not hot enough to micro optimize the nmethod entry barrier with an out-of-line stub
352   bs->nmethod_entry_barrier(this, NULL /* slow_path */, NULL /* continuation */);
353 
354   if (verified_inline_entry_label != NULL) {
355     // Jump here from the scalarized entry points that already created the frame.
356     bind(*verified_inline_entry_label);
357   }
358 }
359 
360 void C1_MacroAssembler::verified_entry(bool breakAtEntry) {
361   if (breakAtEntry || VerifyFPU) {
362     // Verified Entry first instruction should be 5 bytes long for correct
363     // patching by patch_verified_entry().
364     //
365     // Breakpoint 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 (breakAtEntry) int3();
372   // build frame
373   IA32_ONLY( verify_FPU(0, "method_entry"); )
374 }
375 
376 int C1_MacroAssembler::scalarized_entry(const CompiledEntrySignature* ces, int frame_size_in_bytes, int bang_size_in_bytes, int sp_offset_for_orig_pc, Label& verified_inline_entry_label, bool is_inline_ro_entry) {
377   assert(InlineTypePassFieldsAsArgs, "sanity");
378   // Make sure there is enough stack space for this method's activation.
379   assert(bang_size_in_bytes >= frame_size_in_bytes, "stack bang size incorrect");
380   generate_stack_overflow_check(bang_size_in_bytes);
381 
382   GrowableArray<SigEntry>* sig    = &ces->sig();
383   GrowableArray<SigEntry>* sig_cc = is_inline_ro_entry ? &ces->sig_cc_ro() : &ces->sig_cc();
384   VMRegPair* regs      = ces->regs();
385   VMRegPair* regs_cc   = is_inline_ro_entry ? ces->regs_cc_ro() : ces->regs_cc();
386   int args_on_stack    = ces->args_on_stack();
387   int args_on_stack_cc = is_inline_ro_entry ? ces->args_on_stack_cc_ro() : ces->args_on_stack_cc();
388 
389   assert(sig->length() <= sig_cc->length(), "Zero-sized inline class not allowed!");
390   BasicType* sig_bt = NEW_RESOURCE_ARRAY(BasicType, sig_cc->length());
391   int args_passed = sig->length();
392   int args_passed_cc = SigEntry::fill_sig_bt(sig_cc, sig_bt);
393 
394   // Create a temp frame so we can call into the runtime. It must be properly set up to accommodate GC.
395   build_frame_helper(frame_size_in_bytes, sp_offset_for_orig_pc, 0, true, ces->c1_needs_stack_repair());
396 
397   // The runtime call might safepoint, make sure nmethod entry barrier is executed
398   BarrierSetAssembler* bs = BarrierSet::barrier_set()->barrier_set_assembler();
399   // C1 code is not hot enough to micro optimize the nmethod entry barrier with an out-of-line stub
400   bs->nmethod_entry_barrier(this, NULL /* slow_path */, NULL /* continuation */);
401 
402   // FIXME -- call runtime only if we cannot in-line allocate all the incoming inline type args.
403   movptr(rbx, (intptr_t)(ces->method()));
404   if (is_inline_ro_entry) {
405     call(RuntimeAddress(Runtime1::entry_for(Runtime1::buffer_inline_args_no_receiver_id)));
406   } else {
407     call(RuntimeAddress(Runtime1::entry_for(Runtime1::buffer_inline_args_id)));
408   }
409   int rt_call_offset = offset();
410 
411   // Remove the temp frame
412   addptr(rsp, frame_size_in_bytes);
413   pop(rbp);
414 
415   // Check if we need to extend the stack for packing
416   int sp_inc = 0;
417   if (args_on_stack > args_on_stack_cc) {
418     sp_inc = extend_stack_for_inline_args(args_on_stack);
419   }
420 
421   shuffle_inline_args(true, is_inline_ro_entry, sig_cc,
422                       args_passed_cc, args_on_stack_cc, regs_cc, // from
423                       args_passed, args_on_stack, regs,          // to
424                       sp_inc, rax);
425 
426   // Create the real frame. Below jump will then skip over the stack banging and frame
427   // setup code in the verified_inline_entry (which has a different real_frame_size).
428   build_frame_helper(frame_size_in_bytes, sp_offset_for_orig_pc, sp_inc, false, ces->c1_needs_stack_repair());
429 
430   jmp(verified_inline_entry_label);
431   return rt_call_offset;
432 }
433 
434 void C1_MacroAssembler::load_parameter(int offset_in_words, Register reg) {
435   // rbp, + 0: link
436   //     + 1: return address
437   //     + 2: argument with offset 0
438   //     + 3: argument with offset 1
439   //     + 4: ...
440 
441   movptr(reg, Address(rbp, (offset_in_words + 2) * BytesPerWord));
442 }
443 
444 #ifndef PRODUCT
445 
446 void C1_MacroAssembler::verify_stack_oop(int stack_offset) {
447   if (!VerifyOops) return;
448   verify_oop_addr(Address(rsp, stack_offset));
449 }
450 
451 void C1_MacroAssembler::verify_not_null_oop(Register r) {
452   if (!VerifyOops) return;
453   Label not_null;
454   testptr(r, r);
455   jcc(Assembler::notZero, not_null);
456   stop("non-null oop required");
457   bind(not_null);
458   verify_oop(r);
459 }
460 
461 void C1_MacroAssembler::invalidate_registers(bool inv_rax, bool inv_rbx, bool inv_rcx, bool inv_rdx, bool inv_rsi, bool inv_rdi) {
462 #ifdef ASSERT
463   if (inv_rax) movptr(rax, 0xDEAD);
464   if (inv_rbx) movptr(rbx, 0xDEAD);
465   if (inv_rcx) movptr(rcx, 0xDEAD);
466   if (inv_rdx) movptr(rdx, 0xDEAD);
467   if (inv_rsi) movptr(rsi, 0xDEAD);
468   if (inv_rdi) movptr(rdi, 0xDEAD);
469 #endif
470 }
471 
472 #endif // ifndef PRODUCT