1 /*
   2  * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
   3  * Copyright (c) 2014, 2021, Red Hat Inc. All rights reserved.
   4  * Copyright (c) 2021, Azul Systems, Inc. All rights reserved.
   5  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   6  *
   7  * This code is free software; you can redistribute it and/or modify it
   8  * under the terms of the GNU General Public License version 2 only, as
   9  * published by the Free Software Foundation.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  *
  25  */
  26 
  27 #include "precompiled.hpp"
  28 #include "asm/macroAssembler.hpp"
  29 #include "asm/macroAssembler.inline.hpp"
  30 #include "code/codeCache.hpp"
  31 #include "code/compiledIC.hpp"
  32 #include "code/debugInfoRec.hpp"
  33 #include "code/vtableStubs.hpp"
  34 #include "compiler/oopMap.hpp"
  35 #include "gc/shared/barrierSetAssembler.hpp"
  36 #include "interpreter/interpreter.hpp"
  37 #include "interpreter/interp_masm.hpp"
  38 #include "logging/log.hpp"
  39 #include "memory/resourceArea.hpp"
  40 #include "nativeInst_aarch64.hpp"
  41 #include "oops/klass.inline.hpp"
  42 #include "oops/method.inline.hpp"
  43 #include "prims/methodHandles.hpp"
  44 #include "runtime/continuation.hpp"
  45 #include "runtime/continuationEntry.inline.hpp"
  46 #include "runtime/globals.hpp"
  47 #include "runtime/jniHandles.hpp"
  48 #include "runtime/safepointMechanism.hpp"
  49 #include "runtime/sharedRuntime.hpp"
  50 #include "runtime/signature.hpp"
  51 #include "runtime/stubRoutines.hpp"
  52 #include "runtime/vframeArray.hpp"
  53 #include "utilities/align.hpp"
  54 #include "utilities/formatBuffer.hpp"
  55 #include "vmreg_aarch64.inline.hpp"
  56 #ifdef COMPILER1
  57 #include "c1/c1_Runtime1.hpp"
  58 #endif
  59 #ifdef COMPILER2
  60 #include "adfiles/ad_aarch64.hpp"
  61 #include "opto/runtime.hpp"
  62 #endif
  63 #if INCLUDE_JVMCI
  64 #include "jvmci/jvmciJavaClasses.hpp"
  65 #endif
  66 
  67 #define __ masm->
  68 
  69 const int StackAlignmentInSlots = StackAlignmentInBytes / VMRegImpl::stack_slot_size;
  70 
  71 class SimpleRuntimeFrame {
  72 
  73   public:
  74 
  75   // Most of the runtime stubs have this simple frame layout.
  76   // This class exists to make the layout shared in one place.
  77   // Offsets are for compiler stack slots, which are jints.
  78   enum layout {
  79     // The frame sender code expects that rbp will be in the "natural" place and
  80     // will override any oopMap setting for it. We must therefore force the layout
  81     // so that it agrees with the frame sender code.
  82     // we don't expect any arg reg save area so aarch64 asserts that
  83     // frame::arg_reg_save_area_bytes == 0
  84     rfp_off = 0,
  85     rfp_off2,
  86     return_off, return_off2,
  87     framesize
  88   };
  89 };
  90 
  91 // FIXME -- this is used by C1
  92 class RegisterSaver {
  93   const bool _save_vectors;
  94  public:
  95   RegisterSaver(bool save_vectors) : _save_vectors(save_vectors) {}
  96 
  97   OopMap* save_live_registers(MacroAssembler* masm, int additional_frame_words, int* total_frame_words);
  98   void restore_live_registers(MacroAssembler* masm);
  99 
 100   // Offsets into the register save area
 101   // Used by deoptimization when it is managing result register
 102   // values on its own
 103 
 104   int reg_offset_in_bytes(Register r);
 105   int r0_offset_in_bytes()    { return reg_offset_in_bytes(r0); }
 106   int rscratch1_offset_in_bytes()    { return reg_offset_in_bytes(rscratch1); }
 107   int v0_offset_in_bytes();
 108 
 109   // Total stack size in bytes for saving sve predicate registers.
 110   int total_sve_predicate_in_bytes();
 111 
 112   // Capture info about frame layout
 113   // Note this is only correct when not saving full vectors.
 114   enum layout {
 115                 fpu_state_off = 0,
 116                 fpu_state_end = fpu_state_off + FPUStateSizeInWords - 1,
 117                 // The frame sender code expects that rfp will be in
 118                 // the "natural" place and will override any oopMap
 119                 // setting for it. We must therefore force the layout
 120                 // so that it agrees with the frame sender code.
 121                 r0_off = fpu_state_off + FPUStateSizeInWords,
 122                 rfp_off = r0_off + (Register::number_of_registers - 2) * Register::max_slots_per_register,
 123                 return_off = rfp_off + Register::max_slots_per_register,      // slot for return address
 124                 reg_save_size = return_off + Register::max_slots_per_register};
 125 
 126 };
 127 
 128 int RegisterSaver::reg_offset_in_bytes(Register r) {
 129   // The integer registers are located above the floating point
 130   // registers in the stack frame pushed by save_live_registers() so the
 131   // offset depends on whether we are saving full vectors, and whether
 132   // those vectors are NEON or SVE.
 133 
 134   int slots_per_vect = FloatRegister::save_slots_per_register;
 135 
 136 #if COMPILER2_OR_JVMCI
 137   if (_save_vectors) {
 138     slots_per_vect = FloatRegister::slots_per_neon_register;
 139 
 140 #ifdef COMPILER2
 141     if (Matcher::supports_scalable_vector()) {
 142       slots_per_vect = Matcher::scalable_vector_reg_size(T_FLOAT);
 143     }
 144 #endif
 145   }
 146 #endif
 147 
 148   int r0_offset = v0_offset_in_bytes() + (slots_per_vect * FloatRegister::number_of_registers) * BytesPerInt;
 149   return r0_offset + r->encoding() * wordSize;
 150 }
 151 
 152 int RegisterSaver::v0_offset_in_bytes() {
 153   // The floating point registers are located above the predicate registers if
 154   // they are present in the stack frame pushed by save_live_registers(). So the
 155   // offset depends on the saved total predicate vectors in the stack frame.
 156   return (total_sve_predicate_in_bytes() / VMRegImpl::stack_slot_size) * BytesPerInt;
 157 }
 158 
 159 int RegisterSaver::total_sve_predicate_in_bytes() {
 160 #ifdef COMPILER2
 161   if (_save_vectors && Matcher::supports_scalable_vector()) {
 162     return (Matcher::scalable_vector_reg_size(T_BYTE) >> LogBitsPerByte) *
 163            PRegister::number_of_registers;
 164   }
 165 #endif
 166   return 0;
 167 }
 168 
 169 OopMap* RegisterSaver::save_live_registers(MacroAssembler* masm, int additional_frame_words, int* total_frame_words) {
 170   bool use_sve = false;
 171   int sve_vector_size_in_bytes = 0;
 172   int sve_vector_size_in_slots = 0;
 173   int sve_predicate_size_in_slots = 0;
 174   int total_predicate_in_bytes = total_sve_predicate_in_bytes();
 175   int total_predicate_in_slots = total_predicate_in_bytes / VMRegImpl::stack_slot_size;
 176 
 177 #ifdef COMPILER2
 178   use_sve = Matcher::supports_scalable_vector();
 179   if (use_sve) {
 180     sve_vector_size_in_bytes = Matcher::scalable_vector_reg_size(T_BYTE);
 181     sve_vector_size_in_slots = Matcher::scalable_vector_reg_size(T_FLOAT);
 182     sve_predicate_size_in_slots = Matcher::scalable_predicate_reg_slots();
 183   }
 184 #endif
 185 
 186 #if COMPILER2_OR_JVMCI
 187   if (_save_vectors) {
 188     int extra_save_slots_per_register = 0;
 189     // Save upper half of vector registers
 190     if (use_sve) {
 191       extra_save_slots_per_register = sve_vector_size_in_slots - FloatRegister::save_slots_per_register;
 192     } else {
 193       extra_save_slots_per_register = FloatRegister::extra_save_slots_per_neon_register;
 194     }
 195     int extra_vector_bytes = extra_save_slots_per_register *
 196                              VMRegImpl::stack_slot_size *
 197                              FloatRegister::number_of_registers;
 198     additional_frame_words += ((extra_vector_bytes + total_predicate_in_bytes) / wordSize);
 199   }
 200 #else
 201   assert(!_save_vectors, "vectors are generated only by C2 and JVMCI");
 202 #endif
 203 
 204   int frame_size_in_bytes = align_up(additional_frame_words * wordSize +
 205                                      reg_save_size * BytesPerInt, 16);
 206   // OopMap frame size is in compiler stack slots (jint's) not bytes or words
 207   int frame_size_in_slots = frame_size_in_bytes / BytesPerInt;
 208   // The caller will allocate additional_frame_words
 209   int additional_frame_slots = additional_frame_words * wordSize / BytesPerInt;
 210   // CodeBlob frame size is in words.
 211   int frame_size_in_words = frame_size_in_bytes / wordSize;
 212   *total_frame_words = frame_size_in_words;
 213 
 214   // Save Integer and Float registers.
 215   __ enter();
 216   __ push_CPU_state(_save_vectors, use_sve, sve_vector_size_in_bytes, total_predicate_in_bytes);
 217 
 218   // Set an oopmap for the call site.  This oopmap will map all
 219   // oop-registers and debug-info registers as callee-saved.  This
 220   // will allow deoptimization at this safepoint to find all possible
 221   // debug-info recordings, as well as let GC find all oops.
 222 
 223   OopMapSet *oop_maps = new OopMapSet();
 224   OopMap* oop_map = new OopMap(frame_size_in_slots, 0);
 225 
 226   for (int i = 0; i < Register::number_of_registers; i++) {
 227     Register r = as_Register(i);
 228     if (i <= rfp->encoding() && r != rscratch1 && r != rscratch2) {
 229       // SP offsets are in 4-byte words.
 230       // Register slots are 8 bytes wide, 32 floating-point registers.
 231       int sp_offset = Register::max_slots_per_register * i +
 232                       FloatRegister::save_slots_per_register * FloatRegister::number_of_registers;
 233       oop_map->set_callee_saved(VMRegImpl::stack2reg(sp_offset + additional_frame_slots), r->as_VMReg());
 234     }
 235   }
 236 
 237   for (int i = 0; i < FloatRegister::number_of_registers; i++) {
 238     FloatRegister r = as_FloatRegister(i);
 239     int sp_offset = 0;
 240     if (_save_vectors) {
 241       sp_offset = use_sve ? (total_predicate_in_slots + sve_vector_size_in_slots * i) :
 242                             (FloatRegister::slots_per_neon_register * i);
 243     } else {
 244       sp_offset = FloatRegister::save_slots_per_register * i;
 245     }
 246     oop_map->set_callee_saved(VMRegImpl::stack2reg(sp_offset), r->as_VMReg());
 247   }
 248 
 249   return oop_map;
 250 }
 251 
 252 void RegisterSaver::restore_live_registers(MacroAssembler* masm) {
 253 #ifdef COMPILER2
 254   __ pop_CPU_state(_save_vectors, Matcher::supports_scalable_vector(),
 255                    Matcher::scalable_vector_reg_size(T_BYTE), total_sve_predicate_in_bytes());
 256 #else
 257 #if !INCLUDE_JVMCI
 258   assert(!_save_vectors, "vectors are generated only by C2 and JVMCI");
 259 #endif
 260   __ pop_CPU_state(_save_vectors);
 261 #endif
 262   __ ldp(rfp, lr, Address(__ post(sp, 2 * wordSize)));
 263   __ authenticate_return_address();
 264 }
 265 
 266 // Is vector's size (in bytes) bigger than a size saved by default?
 267 // 8 bytes vector registers are saved by default on AArch64.
 268 // The SVE supported min vector size is 8 bytes and we need to save
 269 // predicate registers when the vector size is 8 bytes as well.
 270 bool SharedRuntime::is_wide_vector(int size) {
 271   return size > 8 || (UseSVE > 0 && size >= 8);
 272 }
 273 
 274 // ---------------------------------------------------------------------------
 275 // Read the array of BasicTypes from a signature, and compute where the
 276 // arguments should go.  Values in the VMRegPair regs array refer to 4-byte
 277 // quantities.  Values less than VMRegImpl::stack0 are registers, those above
 278 // refer to 4-byte stack slots.  All stack slots are based off of the stack pointer
 279 // as framesizes are fixed.
 280 // VMRegImpl::stack0 refers to the first slot 0(sp).
 281 // and VMRegImpl::stack0+1 refers to the memory word 4-byes higher.
 282 // Register up to Register::number_of_registers are the 64-bit
 283 // integer registers.
 284 
 285 // Note: the INPUTS in sig_bt are in units of Java argument words,
 286 // which are 64-bit.  The OUTPUTS are in 32-bit units.
 287 
 288 // The Java calling convention is a "shifted" version of the C ABI.
 289 // By skipping the first C ABI register we can call non-static jni
 290 // methods with small numbers of arguments without having to shuffle
 291 // the arguments at all. Since we control the java ABI we ought to at
 292 // least get some advantage out of it.
 293 
 294 int SharedRuntime::java_calling_convention(const BasicType *sig_bt,
 295                                            VMRegPair *regs,
 296                                            int total_args_passed) {
 297 
 298   // Create the mapping between argument positions and
 299   // registers.
 300   static const Register INT_ArgReg[Argument::n_int_register_parameters_j] = {
 301     j_rarg0, j_rarg1, j_rarg2, j_rarg3, j_rarg4, j_rarg5, j_rarg6, j_rarg7
 302   };
 303   static const FloatRegister FP_ArgReg[Argument::n_float_register_parameters_j] = {
 304     j_farg0, j_farg1, j_farg2, j_farg3,
 305     j_farg4, j_farg5, j_farg6, j_farg7
 306   };
 307 
 308 
 309   uint int_args = 0;
 310   uint fp_args = 0;
 311   uint stk_args = 0;
 312 
 313   for (int i = 0; i < total_args_passed; i++) {
 314     switch (sig_bt[i]) {
 315     case T_BOOLEAN:
 316     case T_CHAR:
 317     case T_BYTE:
 318     case T_SHORT:
 319     case T_INT:
 320       if (int_args < Argument::n_int_register_parameters_j) {
 321         regs[i].set1(INT_ArgReg[int_args++]->as_VMReg());
 322       } else {
 323         stk_args = align_up(stk_args, 2);
 324         regs[i].set1(VMRegImpl::stack2reg(stk_args));
 325         stk_args += 1;
 326       }
 327       break;
 328     case T_VOID:
 329       // halves of T_LONG or T_DOUBLE
 330       assert(i != 0 && (sig_bt[i - 1] == T_LONG || sig_bt[i - 1] == T_DOUBLE), "expecting half");
 331       regs[i].set_bad();
 332       break;
 333     case T_LONG:
 334       assert((i + 1) < total_args_passed && sig_bt[i + 1] == T_VOID, "expecting half");
 335       // fall through
 336     case T_OBJECT:
 337     case T_ARRAY:
 338     case T_ADDRESS:
 339       if (int_args < Argument::n_int_register_parameters_j) {
 340         regs[i].set2(INT_ArgReg[int_args++]->as_VMReg());
 341       } else {
 342         stk_args = align_up(stk_args, 2);
 343         regs[i].set2(VMRegImpl::stack2reg(stk_args));
 344         stk_args += 2;
 345       }
 346       break;
 347     case T_FLOAT:
 348       if (fp_args < Argument::n_float_register_parameters_j) {
 349         regs[i].set1(FP_ArgReg[fp_args++]->as_VMReg());
 350       } else {
 351         stk_args = align_up(stk_args, 2);
 352         regs[i].set1(VMRegImpl::stack2reg(stk_args));
 353         stk_args += 1;
 354       }
 355       break;
 356     case T_DOUBLE:
 357       assert((i + 1) < total_args_passed && sig_bt[i + 1] == T_VOID, "expecting half");
 358       if (fp_args < Argument::n_float_register_parameters_j) {
 359         regs[i].set2(FP_ArgReg[fp_args++]->as_VMReg());
 360       } else {
 361         stk_args = align_up(stk_args, 2);
 362         regs[i].set2(VMRegImpl::stack2reg(stk_args));
 363         stk_args += 2;
 364       }
 365       break;
 366     default:
 367       ShouldNotReachHere();
 368       break;
 369     }
 370   }
 371 
 372   return stk_args;
 373 }
 374 
 375 // Patch the callers callsite with entry to compiled code if it exists.
 376 static void patch_callers_callsite(MacroAssembler *masm) {
 377   Label L;
 378   __ ldr(rscratch1, Address(rmethod, in_bytes(Method::code_offset())));
 379   __ cbz(rscratch1, L);
 380 
 381   __ enter();
 382   __ push_CPU_state();
 383 
 384   // VM needs caller's callsite
 385   // VM needs target method
 386   // This needs to be a long call since we will relocate this adapter to
 387   // the codeBuffer and it may not reach
 388 
 389 #ifndef PRODUCT
 390   assert(frame::arg_reg_save_area_bytes == 0, "not expecting frame reg save area");
 391 #endif
 392 
 393   __ mov(c_rarg0, rmethod);
 394   __ mov(c_rarg1, lr);
 395   __ authenticate_return_address(c_rarg1);
 396   __ lea(rscratch1, RuntimeAddress(CAST_FROM_FN_PTR(address, SharedRuntime::fixup_callers_callsite)));
 397   __ blr(rscratch1);
 398 
 399   // Explicit isb required because fixup_callers_callsite may change the code
 400   // stream.
 401   __ safepoint_isb();
 402 
 403   __ pop_CPU_state();
 404   // restore sp
 405   __ leave();
 406   __ bind(L);
 407 }
 408 
 409 static void gen_c2i_adapter(MacroAssembler *masm,
 410                             int total_args_passed,
 411                             int comp_args_on_stack,
 412                             const BasicType *sig_bt,
 413                             const VMRegPair *regs,
 414                             Label& skip_fixup) {
 415   // Before we get into the guts of the C2I adapter, see if we should be here
 416   // at all.  We've come from compiled code and are attempting to jump to the
 417   // interpreter, which means the caller made a static call to get here
 418   // (vcalls always get a compiled target if there is one).  Check for a
 419   // compiled target.  If there is one, we need to patch the caller's call.
 420   patch_callers_callsite(masm);
 421 
 422   __ bind(skip_fixup);
 423 
 424   int words_pushed = 0;
 425 
 426   // Since all args are passed on the stack, total_args_passed *
 427   // Interpreter::stackElementSize is the space we need.
 428 
 429   int extraspace = total_args_passed * Interpreter::stackElementSize;
 430 
 431   __ mov(r19_sender_sp, sp);
 432 
 433   // stack is aligned, keep it that way
 434   extraspace = align_up(extraspace, 2*wordSize);
 435 
 436   if (extraspace)
 437     __ sub(sp, sp, extraspace);
 438 
 439   // Now write the args into the outgoing interpreter space
 440   for (int i = 0; i < total_args_passed; i++) {
 441     if (sig_bt[i] == T_VOID) {
 442       assert(i > 0 && (sig_bt[i-1] == T_LONG || sig_bt[i-1] == T_DOUBLE), "missing half");
 443       continue;
 444     }
 445 
 446     // offset to start parameters
 447     int st_off   = (total_args_passed - i - 1) * Interpreter::stackElementSize;
 448     int next_off = st_off - Interpreter::stackElementSize;
 449 
 450     // Say 4 args:
 451     // i   st_off
 452     // 0   32 T_LONG
 453     // 1   24 T_VOID
 454     // 2   16 T_OBJECT
 455     // 3    8 T_BOOL
 456     // -    0 return address
 457     //
 458     // However to make thing extra confusing. Because we can fit a Java long/double in
 459     // a single slot on a 64 bt vm and it would be silly to break them up, the interpreter
 460     // leaves one slot empty and only stores to a single slot. In this case the
 461     // slot that is occupied is the T_VOID slot. See I said it was confusing.
 462 
 463     VMReg r_1 = regs[i].first();
 464     VMReg r_2 = regs[i].second();
 465     if (!r_1->is_valid()) {
 466       assert(!r_2->is_valid(), "");
 467       continue;
 468     }
 469     if (r_1->is_stack()) {
 470       // memory to memory use rscratch1
 471       int ld_off = (r_1->reg2stack() * VMRegImpl::stack_slot_size
 472                     + extraspace
 473                     + words_pushed * wordSize);
 474       if (!r_2->is_valid()) {
 475         // sign extend??
 476         __ ldrw(rscratch1, Address(sp, ld_off));
 477         __ str(rscratch1, Address(sp, st_off));
 478 
 479       } else {
 480 
 481         __ ldr(rscratch1, Address(sp, ld_off));
 482 
 483         // Two VMREgs|OptoRegs can be T_OBJECT, T_ADDRESS, T_DOUBLE, T_LONG
 484         // T_DOUBLE and T_LONG use two slots in the interpreter
 485         if ( sig_bt[i] == T_LONG || sig_bt[i] == T_DOUBLE) {
 486           // ld_off == LSW, ld_off+wordSize == MSW
 487           // st_off == MSW, next_off == LSW
 488           __ str(rscratch1, Address(sp, next_off));
 489 #ifdef ASSERT
 490           // Overwrite the unused slot with known junk
 491           __ mov(rscratch1, (uint64_t)0xdeadffffdeadaaaaull);
 492           __ str(rscratch1, Address(sp, st_off));
 493 #endif /* ASSERT */
 494         } else {
 495           __ str(rscratch1, Address(sp, st_off));
 496         }
 497       }
 498     } else if (r_1->is_Register()) {
 499       Register r = r_1->as_Register();
 500       if (!r_2->is_valid()) {
 501         // must be only an int (or less ) so move only 32bits to slot
 502         // why not sign extend??
 503         __ str(r, Address(sp, st_off));
 504       } else {
 505         // Two VMREgs|OptoRegs can be T_OBJECT, T_ADDRESS, T_DOUBLE, T_LONG
 506         // T_DOUBLE and T_LONG use two slots in the interpreter
 507         if ( sig_bt[i] == T_LONG || sig_bt[i] == T_DOUBLE) {
 508           // jlong/double in gpr
 509 #ifdef ASSERT
 510           // Overwrite the unused slot with known junk
 511           __ mov(rscratch1, (uint64_t)0xdeadffffdeadaaabull);
 512           __ str(rscratch1, Address(sp, st_off));
 513 #endif /* ASSERT */
 514           __ str(r, Address(sp, next_off));
 515         } else {
 516           __ str(r, Address(sp, st_off));
 517         }
 518       }
 519     } else {
 520       assert(r_1->is_FloatRegister(), "");
 521       if (!r_2->is_valid()) {
 522         // only a float use just part of the slot
 523         __ strs(r_1->as_FloatRegister(), Address(sp, st_off));
 524       } else {
 525 #ifdef ASSERT
 526         // Overwrite the unused slot with known junk
 527         __ mov(rscratch1, (uint64_t)0xdeadffffdeadaaacull);
 528         __ str(rscratch1, Address(sp, st_off));
 529 #endif /* ASSERT */
 530         __ strd(r_1->as_FloatRegister(), Address(sp, next_off));
 531       }
 532     }
 533   }
 534 
 535   __ mov(esp, sp); // Interp expects args on caller's expression stack
 536 
 537   __ ldr(rscratch1, Address(rmethod, in_bytes(Method::interpreter_entry_offset())));
 538   __ br(rscratch1);
 539 }
 540 
 541 
 542 void SharedRuntime::gen_i2c_adapter(MacroAssembler *masm,
 543                                     int total_args_passed,
 544                                     int comp_args_on_stack,
 545                                     const BasicType *sig_bt,
 546                                     const VMRegPair *regs) {
 547 
 548   // Note: r19_sender_sp contains the senderSP on entry. We must
 549   // preserve it since we may do a i2c -> c2i transition if we lose a
 550   // race where compiled code goes non-entrant while we get args
 551   // ready.
 552 
 553   // Adapters are frameless.
 554 
 555   // An i2c adapter is frameless because the *caller* frame, which is
 556   // interpreted, routinely repairs its own esp (from
 557   // interpreter_frame_last_sp), even if a callee has modified the
 558   // stack pointer.  It also recalculates and aligns sp.
 559 
 560   // A c2i adapter is frameless because the *callee* frame, which is
 561   // interpreted, routinely repairs its caller's sp (from sender_sp,
 562   // which is set up via the senderSP register).
 563 
 564   // In other words, if *either* the caller or callee is interpreted, we can
 565   // get the stack pointer repaired after a call.
 566 
 567   // This is why c2i and i2c adapters cannot be indefinitely composed.
 568   // In particular, if a c2i adapter were to somehow call an i2c adapter,
 569   // both caller and callee would be compiled methods, and neither would
 570   // clean up the stack pointer changes performed by the two adapters.
 571   // If this happens, control eventually transfers back to the compiled
 572   // caller, but with an uncorrected stack, causing delayed havoc.
 573 
 574   if (VerifyAdapterCalls &&
 575       (Interpreter::code() != nullptr || StubRoutines::final_stubs_code() != nullptr)) {
 576 #if 0
 577     // So, let's test for cascading c2i/i2c adapters right now.
 578     //  assert(Interpreter::contains($return_addr) ||
 579     //         StubRoutines::contains($return_addr),
 580     //         "i2c adapter must return to an interpreter frame");
 581     __ block_comment("verify_i2c { ");
 582     Label L_ok;
 583     if (Interpreter::code() != nullptr) {
 584       range_check(masm, rax, r11,
 585                   Interpreter::code()->code_start(), Interpreter::code()->code_end(),
 586                   L_ok);
 587     }
 588     if (StubRoutines::initial_stubs_code() != nullptr) {
 589       range_check(masm, rax, r11,
 590                   StubRoutines::initial_stubs_code()->code_begin(),
 591                   StubRoutines::initial_stubs_code()->code_end(),
 592                   L_ok);
 593     }
 594     if (StubRoutines::final_stubs_code() != nullptr) {
 595       range_check(masm, rax, r11,
 596                   StubRoutines::final_stubs_code()->code_begin(),
 597                   StubRoutines::final_stubs_code()->code_end(),
 598                   L_ok);
 599     }
 600     const char* msg = "i2c adapter must return to an interpreter frame";
 601     __ block_comment(msg);
 602     __ stop(msg);
 603     __ bind(L_ok);
 604     __ block_comment("} verify_i2ce ");
 605 #endif
 606   }
 607 
 608   // Cut-out for having no stack args.
 609   int comp_words_on_stack = align_up(comp_args_on_stack*VMRegImpl::stack_slot_size, wordSize)>>LogBytesPerWord;
 610   if (comp_args_on_stack) {
 611     __ sub(rscratch1, sp, comp_words_on_stack * wordSize);
 612     __ andr(sp, rscratch1, -16);
 613   }
 614 
 615   // Will jump to the compiled code just as if compiled code was doing it.
 616   // Pre-load the register-jump target early, to schedule it better.
 617   __ ldr(rscratch1, Address(rmethod, in_bytes(Method::from_compiled_offset())));
 618 
 619 #if INCLUDE_JVMCI
 620   if (EnableJVMCI) {
 621     // check if this call should be routed towards a specific entry point
 622     __ ldr(rscratch2, Address(rthread, in_bytes(JavaThread::jvmci_alternate_call_target_offset())));
 623     Label no_alternative_target;
 624     __ cbz(rscratch2, no_alternative_target);
 625     __ mov(rscratch1, rscratch2);
 626     __ str(zr, Address(rthread, in_bytes(JavaThread::jvmci_alternate_call_target_offset())));
 627     __ bind(no_alternative_target);
 628   }
 629 #endif // INCLUDE_JVMCI
 630 
 631   // Now generate the shuffle code.
 632   for (int i = 0; i < total_args_passed; i++) {
 633     if (sig_bt[i] == T_VOID) {
 634       assert(i > 0 && (sig_bt[i-1] == T_LONG || sig_bt[i-1] == T_DOUBLE), "missing half");
 635       continue;
 636     }
 637 
 638     // Pick up 0, 1 or 2 words from SP+offset.
 639 
 640     assert(!regs[i].second()->is_valid() || regs[i].first()->next() == regs[i].second(),
 641             "scrambled load targets?");
 642     // Load in argument order going down.
 643     int ld_off = (total_args_passed - i - 1)*Interpreter::stackElementSize;
 644     // Point to interpreter value (vs. tag)
 645     int next_off = ld_off - Interpreter::stackElementSize;
 646     //
 647     //
 648     //
 649     VMReg r_1 = regs[i].first();
 650     VMReg r_2 = regs[i].second();
 651     if (!r_1->is_valid()) {
 652       assert(!r_2->is_valid(), "");
 653       continue;
 654     }
 655     if (r_1->is_stack()) {
 656       // Convert stack slot to an SP offset (+ wordSize to account for return address )
 657       int st_off = regs[i].first()->reg2stack()*VMRegImpl::stack_slot_size;
 658       if (!r_2->is_valid()) {
 659         // sign extend???
 660         __ ldrsw(rscratch2, Address(esp, ld_off));
 661         __ str(rscratch2, Address(sp, st_off));
 662       } else {
 663         //
 664         // We are using two optoregs. This can be either T_OBJECT,
 665         // T_ADDRESS, T_LONG, or T_DOUBLE the interpreter allocates
 666         // two slots but only uses one for thr T_LONG or T_DOUBLE case
 667         // So we must adjust where to pick up the data to match the
 668         // interpreter.
 669         //
 670         // Interpreter local[n] == MSW, local[n+1] == LSW however locals
 671         // are accessed as negative so LSW is at LOW address
 672 
 673         // ld_off is MSW so get LSW
 674         const int offset = (sig_bt[i]==T_LONG||sig_bt[i]==T_DOUBLE)?
 675                            next_off : ld_off;
 676         __ ldr(rscratch2, Address(esp, offset));
 677         // st_off is LSW (i.e. reg.first())
 678         __ str(rscratch2, Address(sp, st_off));
 679       }
 680     } else if (r_1->is_Register()) {  // Register argument
 681       Register r = r_1->as_Register();
 682       if (r_2->is_valid()) {
 683         //
 684         // We are using two VMRegs. This can be either T_OBJECT,
 685         // T_ADDRESS, T_LONG, or T_DOUBLE the interpreter allocates
 686         // two slots but only uses one for thr T_LONG or T_DOUBLE case
 687         // So we must adjust where to pick up the data to match the
 688         // interpreter.
 689 
 690         const int offset = (sig_bt[i]==T_LONG||sig_bt[i]==T_DOUBLE)?
 691                            next_off : ld_off;
 692 
 693         // this can be a misaligned move
 694         __ ldr(r, Address(esp, offset));
 695       } else {
 696         // sign extend and use a full word?
 697         __ ldrw(r, Address(esp, ld_off));
 698       }
 699     } else {
 700       if (!r_2->is_valid()) {
 701         __ ldrs(r_1->as_FloatRegister(), Address(esp, ld_off));
 702       } else {
 703         __ ldrd(r_1->as_FloatRegister(), Address(esp, next_off));
 704       }
 705     }
 706   }
 707 
 708   __ mov(rscratch2, rscratch1);
 709   __ push_cont_fastpath(rthread); // Set JavaThread::_cont_fastpath to the sp of the oldest interpreted frame we know about; kills rscratch1
 710   __ mov(rscratch1, rscratch2);
 711 
 712   // 6243940 We might end up in handle_wrong_method if
 713   // the callee is deoptimized as we race thru here. If that
 714   // happens we don't want to take a safepoint because the
 715   // caller frame will look interpreted and arguments are now
 716   // "compiled" so it is much better to make this transition
 717   // invisible to the stack walking code. Unfortunately if
 718   // we try and find the callee by normal means a safepoint
 719   // is possible. So we stash the desired callee in the thread
 720   // and the vm will find there should this case occur.
 721 
 722   __ str(rmethod, Address(rthread, JavaThread::callee_target_offset()));
 723 
 724   __ br(rscratch1);
 725 }
 726 
 727 // ---------------------------------------------------------------
 728 AdapterHandlerEntry* SharedRuntime::generate_i2c2i_adapters(MacroAssembler *masm,
 729                                                             int total_args_passed,
 730                                                             int comp_args_on_stack,
 731                                                             const BasicType *sig_bt,
 732                                                             const VMRegPair *regs,
 733                                                             AdapterFingerPrint* fingerprint) {
 734   address i2c_entry = __ pc();
 735 
 736   gen_i2c_adapter(masm, total_args_passed, comp_args_on_stack, sig_bt, regs);
 737 
 738   address c2i_unverified_entry = __ pc();
 739   Label skip_fixup;
 740 
 741   Register data = rscratch2;
 742   Register receiver = j_rarg0;
 743   Register tmp = r10;  // A call-clobbered register not used for arg passing
 744 
 745   // -------------------------------------------------------------------------
 746   // Generate a C2I adapter.  On entry we know rmethod holds the Method* during calls
 747   // to the interpreter.  The args start out packed in the compiled layout.  They
 748   // need to be unpacked into the interpreter layout.  This will almost always
 749   // require some stack space.  We grow the current (compiled) stack, then repack
 750   // the args.  We  finally end in a jump to the generic interpreter entry point.
 751   // On exit from the interpreter, the interpreter will restore our SP (lest the
 752   // compiled code, which relies solely on SP and not FP, get sick).
 753 
 754   {
 755     __ block_comment("c2i_unverified_entry {");
 756     // Method might have been compiled since the call site was patched to
 757     // interpreted; if that is the case treat it as a miss so we can get
 758     // the call site corrected.
 759     __ ic_check(1 /* end_alignment */);
 760     __ ldr(rmethod, Address(data, CompiledICData::speculated_method_offset()));
 761 
 762     __ ldr(rscratch1, Address(rmethod, in_bytes(Method::code_offset())));
 763     __ cbz(rscratch1, skip_fixup);
 764     __ far_jump(RuntimeAddress(SharedRuntime::get_ic_miss_stub()));
 765     __ block_comment("} c2i_unverified_entry");
 766   }
 767 
 768   address c2i_entry = __ pc();
 769 
 770   // Class initialization barrier for static methods
 771   address c2i_no_clinit_check_entry = nullptr;
 772   if (VM_Version::supports_fast_class_init_checks()) {
 773     Label L_skip_barrier;
 774 
 775     { // Bypass the barrier for non-static methods
 776       __ ldrw(rscratch1, Address(rmethod, Method::access_flags_offset()));
 777       __ andsw(zr, rscratch1, JVM_ACC_STATIC);
 778       __ br(Assembler::EQ, L_skip_barrier); // non-static
 779     }
 780 
 781     __ load_method_holder(rscratch2, rmethod);
 782     __ clinit_barrier(rscratch2, rscratch1, &L_skip_barrier);
 783     __ far_jump(RuntimeAddress(SharedRuntime::get_handle_wrong_method_stub()));
 784 
 785     __ bind(L_skip_barrier);
 786     c2i_no_clinit_check_entry = __ pc();
 787   }
 788 
 789   BarrierSetAssembler* bs = BarrierSet::barrier_set()->barrier_set_assembler();
 790   bs->c2i_entry_barrier(masm);
 791 
 792   gen_c2i_adapter(masm, total_args_passed, comp_args_on_stack, sig_bt, regs, skip_fixup);
 793 
 794   return AdapterHandlerLibrary::new_entry(fingerprint, i2c_entry, c2i_entry, c2i_unverified_entry, c2i_no_clinit_check_entry);
 795 }
 796 
 797 static int c_calling_convention_priv(const BasicType *sig_bt,
 798                                          VMRegPair *regs,
 799                                          int total_args_passed) {
 800 
 801 // We return the amount of VMRegImpl stack slots we need to reserve for all
 802 // the arguments NOT counting out_preserve_stack_slots.
 803 
 804     static const Register INT_ArgReg[Argument::n_int_register_parameters_c] = {
 805       c_rarg0, c_rarg1, c_rarg2, c_rarg3, c_rarg4, c_rarg5,  c_rarg6,  c_rarg7
 806     };
 807     static const FloatRegister FP_ArgReg[Argument::n_float_register_parameters_c] = {
 808       c_farg0, c_farg1, c_farg2, c_farg3,
 809       c_farg4, c_farg5, c_farg6, c_farg7
 810     };
 811 
 812     uint int_args = 0;
 813     uint fp_args = 0;
 814     uint stk_args = 0; // inc by 2 each time
 815 
 816     for (int i = 0; i < total_args_passed; i++) {
 817       switch (sig_bt[i]) {
 818       case T_BOOLEAN:
 819       case T_CHAR:
 820       case T_BYTE:
 821       case T_SHORT:
 822       case T_INT:
 823         if (int_args < Argument::n_int_register_parameters_c) {
 824           regs[i].set1(INT_ArgReg[int_args++]->as_VMReg());
 825         } else {
 826 #ifdef __APPLE__
 827           // Less-than word types are stored one after another.
 828           // The code is unable to handle this so bailout.
 829           return -1;
 830 #endif
 831           regs[i].set1(VMRegImpl::stack2reg(stk_args));
 832           stk_args += 2;
 833         }
 834         break;
 835       case T_LONG:
 836         assert((i + 1) < total_args_passed && sig_bt[i + 1] == T_VOID, "expecting half");
 837         // fall through
 838       case T_OBJECT:
 839       case T_ARRAY:
 840       case T_ADDRESS:
 841       case T_METADATA:
 842         if (int_args < Argument::n_int_register_parameters_c) {
 843           regs[i].set2(INT_ArgReg[int_args++]->as_VMReg());
 844         } else {
 845           regs[i].set2(VMRegImpl::stack2reg(stk_args));
 846           stk_args += 2;
 847         }
 848         break;
 849       case T_FLOAT:
 850         if (fp_args < Argument::n_float_register_parameters_c) {
 851           regs[i].set1(FP_ArgReg[fp_args++]->as_VMReg());
 852         } else {
 853 #ifdef __APPLE__
 854           // Less-than word types are stored one after another.
 855           // The code is unable to handle this so bailout.
 856           return -1;
 857 #endif
 858           regs[i].set1(VMRegImpl::stack2reg(stk_args));
 859           stk_args += 2;
 860         }
 861         break;
 862       case T_DOUBLE:
 863         assert((i + 1) < total_args_passed && sig_bt[i + 1] == T_VOID, "expecting half");
 864         if (fp_args < Argument::n_float_register_parameters_c) {
 865           regs[i].set2(FP_ArgReg[fp_args++]->as_VMReg());
 866         } else {
 867           regs[i].set2(VMRegImpl::stack2reg(stk_args));
 868           stk_args += 2;
 869         }
 870         break;
 871       case T_VOID: // Halves of longs and doubles
 872         assert(i != 0 && (sig_bt[i - 1] == T_LONG || sig_bt[i - 1] == T_DOUBLE), "expecting half");
 873         regs[i].set_bad();
 874         break;
 875       default:
 876         ShouldNotReachHere();
 877         break;
 878       }
 879     }
 880 
 881   return stk_args;
 882 }
 883 
 884 int SharedRuntime::vector_calling_convention(VMRegPair *regs,
 885                                              uint num_bits,
 886                                              uint total_args_passed) {
 887   Unimplemented();
 888   return 0;
 889 }
 890 
 891 int SharedRuntime::c_calling_convention(const BasicType *sig_bt,
 892                                          VMRegPair *regs,
 893                                          int total_args_passed)
 894 {
 895   int result = c_calling_convention_priv(sig_bt, regs, total_args_passed);
 896   guarantee(result >= 0, "Unsupported arguments configuration");
 897   return result;
 898 }
 899 
 900 
 901 void SharedRuntime::save_native_result(MacroAssembler *masm, BasicType ret_type, int frame_slots) {
 902   // We always ignore the frame_slots arg and just use the space just below frame pointer
 903   // which by this time is free to use
 904   switch (ret_type) {
 905   case T_FLOAT:
 906     __ strs(v0, Address(rfp, -wordSize));
 907     break;
 908   case T_DOUBLE:
 909     __ strd(v0, Address(rfp, -wordSize));
 910     break;
 911   case T_VOID:  break;
 912   default: {
 913     __ str(r0, Address(rfp, -wordSize));
 914     }
 915   }
 916 }
 917 
 918 void SharedRuntime::restore_native_result(MacroAssembler *masm, BasicType ret_type, int frame_slots) {
 919   // We always ignore the frame_slots arg and just use the space just below frame pointer
 920   // which by this time is free to use
 921   switch (ret_type) {
 922   case T_FLOAT:
 923     __ ldrs(v0, Address(rfp, -wordSize));
 924     break;
 925   case T_DOUBLE:
 926     __ ldrd(v0, Address(rfp, -wordSize));
 927     break;
 928   case T_VOID:  break;
 929   default: {
 930     __ ldr(r0, Address(rfp, -wordSize));
 931     }
 932   }
 933 }
 934 static void save_args(MacroAssembler *masm, int arg_count, int first_arg, VMRegPair *args) {
 935   RegSet x;
 936   for ( int i = first_arg ; i < arg_count ; i++ ) {
 937     if (args[i].first()->is_Register()) {
 938       x = x + args[i].first()->as_Register();
 939     } else if (args[i].first()->is_FloatRegister()) {
 940       __ strd(args[i].first()->as_FloatRegister(), Address(__ pre(sp, -2 * wordSize)));
 941     }
 942   }
 943   __ push(x, sp);
 944 }
 945 
 946 static void restore_args(MacroAssembler *masm, int arg_count, int first_arg, VMRegPair *args) {
 947   RegSet x;
 948   for ( int i = first_arg ; i < arg_count ; i++ ) {
 949     if (args[i].first()->is_Register()) {
 950       x = x + args[i].first()->as_Register();
 951     } else {
 952       ;
 953     }
 954   }
 955   __ pop(x, sp);
 956   for ( int i = arg_count - 1 ; i >= first_arg ; i-- ) {
 957     if (args[i].first()->is_Register()) {
 958       ;
 959     } else if (args[i].first()->is_FloatRegister()) {
 960       __ ldrd(args[i].first()->as_FloatRegister(), Address(__ post(sp, 2 * wordSize)));
 961     }
 962   }
 963 }
 964 
 965 static void verify_oop_args(MacroAssembler* masm,
 966                             const methodHandle& method,
 967                             const BasicType* sig_bt,
 968                             const VMRegPair* regs) {
 969   Register temp_reg = r19;  // not part of any compiled calling seq
 970   if (VerifyOops) {
 971     for (int i = 0; i < method->size_of_parameters(); i++) {
 972       if (sig_bt[i] == T_OBJECT ||
 973           sig_bt[i] == T_ARRAY) {
 974         VMReg r = regs[i].first();
 975         assert(r->is_valid(), "bad oop arg");
 976         if (r->is_stack()) {
 977           __ ldr(temp_reg, Address(sp, r->reg2stack() * VMRegImpl::stack_slot_size));
 978           __ verify_oop(temp_reg);
 979         } else {
 980           __ verify_oop(r->as_Register());
 981         }
 982       }
 983     }
 984   }
 985 }
 986 
 987 // on exit, sp points to the ContinuationEntry
 988 static OopMap* continuation_enter_setup(MacroAssembler* masm, int& stack_slots) {
 989   assert(ContinuationEntry::size() % VMRegImpl::stack_slot_size == 0, "");
 990   assert(in_bytes(ContinuationEntry::cont_offset())  % VMRegImpl::stack_slot_size == 0, "");
 991   assert(in_bytes(ContinuationEntry::chunk_offset()) % VMRegImpl::stack_slot_size == 0, "");
 992 
 993   stack_slots += (int)ContinuationEntry::size()/wordSize;
 994   __ sub(sp, sp, (int)ContinuationEntry::size()); // place Continuation metadata
 995 
 996   OopMap* map = new OopMap(((int)ContinuationEntry::size() + wordSize)/ VMRegImpl::stack_slot_size, 0 /* arg_slots*/);
 997 
 998   __ ldr(rscratch1, Address(rthread, JavaThread::cont_entry_offset()));
 999   __ str(rscratch1, Address(sp, ContinuationEntry::parent_offset()));
1000   __ mov(rscratch1, sp); // we can't use sp as the source in str
1001   __ str(rscratch1, Address(rthread, JavaThread::cont_entry_offset()));
1002 
1003   return map;
1004 }
1005 
1006 // on entry c_rarg1 points to the continuation
1007 //          sp points to ContinuationEntry
1008 //          c_rarg3 -- isVirtualThread
1009 static void fill_continuation_entry(MacroAssembler* masm) {
1010 #ifdef ASSERT
1011   __ movw(rscratch1, ContinuationEntry::cookie_value());
1012   __ strw(rscratch1, Address(sp, ContinuationEntry::cookie_offset()));
1013 #endif
1014 
1015   __ str (c_rarg1, Address(sp, ContinuationEntry::cont_offset()));
1016   __ strw(c_rarg3, Address(sp, ContinuationEntry::flags_offset()));
1017   __ str (zr,      Address(sp, ContinuationEntry::chunk_offset()));
1018   __ strw(zr,      Address(sp, ContinuationEntry::argsize_offset()));
1019   __ strw(zr,      Address(sp, ContinuationEntry::pin_count_offset()));
1020 
1021   __ ldr(rscratch1, Address(rthread, JavaThread::cont_fastpath_offset()));
1022   __ str(rscratch1, Address(sp, ContinuationEntry::parent_cont_fastpath_offset()));
1023   __ ldr(rscratch1, Address(rthread, JavaThread::held_monitor_count_offset()));
1024   __ str(rscratch1, Address(sp, ContinuationEntry::parent_held_monitor_count_offset()));
1025 
1026   __ str(zr, Address(rthread, JavaThread::cont_fastpath_offset()));
1027   __ str(zr, Address(rthread, JavaThread::held_monitor_count_offset()));
1028 }
1029 
1030 // on entry, sp points to the ContinuationEntry
1031 // on exit, rfp points to the spilled rfp in the entry frame
1032 static void continuation_enter_cleanup(MacroAssembler* masm) {
1033 #ifndef PRODUCT
1034   Label OK;
1035   __ ldr(rscratch1, Address(rthread, JavaThread::cont_entry_offset()));
1036   __ cmp(sp, rscratch1);
1037   __ br(Assembler::EQ, OK);
1038   __ stop("incorrect sp1");
1039   __ bind(OK);
1040 #endif
1041   __ ldr(rscratch1, Address(sp, ContinuationEntry::parent_cont_fastpath_offset()));
1042   __ str(rscratch1, Address(rthread, JavaThread::cont_fastpath_offset()));
1043 
1044   if (CheckJNICalls) {
1045     // Check if this is a virtual thread continuation
1046     Label L_skip_vthread_code;
1047     __ ldrw(rscratch1, Address(sp, ContinuationEntry::flags_offset()));
1048     __ cbzw(rscratch1, L_skip_vthread_code);
1049 
1050     // If the held monitor count is > 0 and this vthread is terminating then
1051     // it failed to release a JNI monitor. So we issue the same log message
1052     // that JavaThread::exit does.
1053     __ ldr(rscratch1, Address(rthread, JavaThread::jni_monitor_count_offset()));
1054     __ cbz(rscratch1, L_skip_vthread_code);
1055 
1056     // Save return value potentially containing the exception oop in callee-saved R19.
1057     __ mov(r19, r0);
1058     __ call_VM_leaf(CAST_FROM_FN_PTR(address, SharedRuntime::log_jni_monitor_still_held));
1059     // Restore potential return value.
1060     __ mov(r0, r19);
1061 
1062     // For vthreads we have to explicitly zero the JNI monitor count of the carrier
1063     // on termination. The held count is implicitly zeroed below when we restore from
1064     // the parent held count (which has to be zero).
1065     __ str(zr, Address(rthread, JavaThread::jni_monitor_count_offset()));
1066 
1067     __ bind(L_skip_vthread_code);
1068   }
1069 #ifdef ASSERT
1070   else {
1071     // Check if this is a virtual thread continuation
1072     Label L_skip_vthread_code;
1073     __ ldrw(rscratch1, Address(sp, ContinuationEntry::flags_offset()));
1074     __ cbzw(rscratch1, L_skip_vthread_code);
1075 
1076     // See comment just above. If not checking JNI calls the JNI count is only
1077     // needed for assertion checking.
1078     __ str(zr, Address(rthread, JavaThread::jni_monitor_count_offset()));
1079 
1080     __ bind(L_skip_vthread_code);
1081   }
1082 #endif
1083 
1084   __ ldr(rscratch1, Address(sp, ContinuationEntry::parent_held_monitor_count_offset()));
1085   __ str(rscratch1, Address(rthread, JavaThread::held_monitor_count_offset()));
1086 
1087   __ ldr(rscratch2, Address(sp, ContinuationEntry::parent_offset()));
1088   __ str(rscratch2, Address(rthread, JavaThread::cont_entry_offset()));
1089   __ add(rfp, sp, (int)ContinuationEntry::size());
1090 }
1091 
1092 // enterSpecial(Continuation c, boolean isContinue, boolean isVirtualThread)
1093 // On entry: c_rarg1 -- the continuation object
1094 //           c_rarg2 -- isContinue
1095 //           c_rarg3 -- isVirtualThread
1096 static void gen_continuation_enter(MacroAssembler* masm,
1097                                  const methodHandle& method,
1098                                  const BasicType* sig_bt,
1099                                  const VMRegPair* regs,
1100                                  int& exception_offset,
1101                                  OopMapSet*oop_maps,
1102                                  int& frame_complete,
1103                                  int& stack_slots,
1104                                  int& interpreted_entry_offset,
1105                                  int& compiled_entry_offset) {
1106   //verify_oop_args(masm, method, sig_bt, regs);
1107   Address resolve(SharedRuntime::get_resolve_static_call_stub(), relocInfo::static_call_type);
1108 
1109   address start = __ pc();
1110 
1111   Label call_thaw, exit;
1112 
1113   // i2i entry used at interp_only_mode only
1114   interpreted_entry_offset = __ pc() - start;
1115   {
1116 
1117 #ifdef ASSERT
1118     Label is_interp_only;
1119     __ ldrw(rscratch1, Address(rthread, JavaThread::interp_only_mode_offset()));
1120     __ cbnzw(rscratch1, is_interp_only);
1121     __ stop("enterSpecial interpreter entry called when not in interp_only_mode");
1122     __ bind(is_interp_only);
1123 #endif
1124 
1125     // Read interpreter arguments into registers (this is an ad-hoc i2c adapter)
1126     __ ldr(c_rarg1, Address(esp, Interpreter::stackElementSize*2));
1127     __ ldr(c_rarg2, Address(esp, Interpreter::stackElementSize*1));
1128     __ ldr(c_rarg3, Address(esp, Interpreter::stackElementSize*0));
1129     __ push_cont_fastpath(rthread);
1130 
1131     __ enter();
1132     stack_slots = 2; // will be adjusted in setup
1133     OopMap* map = continuation_enter_setup(masm, stack_slots);
1134     // The frame is complete here, but we only record it for the compiled entry, so the frame would appear unsafe,
1135     // but that's okay because at the very worst we'll miss an async sample, but we're in interp_only_mode anyway.
1136 
1137     fill_continuation_entry(masm);
1138 
1139     __ cbnz(c_rarg2, call_thaw);
1140 
1141     const address tr_call = __ trampoline_call(resolve);
1142     if (tr_call == nullptr) {
1143       fatal("CodeCache is full at gen_continuation_enter");
1144     }
1145 
1146     oop_maps->add_gc_map(__ pc() - start, map);
1147     __ post_call_nop();
1148 
1149     __ b(exit);
1150 
1151     address stub = CompiledDirectCall::emit_to_interp_stub(masm, tr_call);
1152     if (stub == nullptr) {
1153       fatal("CodeCache is full at gen_continuation_enter");
1154     }
1155   }
1156 
1157   // compiled entry
1158   __ align(CodeEntryAlignment);
1159   compiled_entry_offset = __ pc() - start;
1160 
1161   __ enter();
1162   stack_slots = 2; // will be adjusted in setup
1163   OopMap* map = continuation_enter_setup(masm, stack_slots);
1164   frame_complete = __ pc() - start;
1165 
1166   fill_continuation_entry(masm);
1167 
1168   __ cbnz(c_rarg2, call_thaw);
1169 
1170   const address tr_call = __ trampoline_call(resolve);
1171   if (tr_call == nullptr) {
1172     fatal("CodeCache is full at gen_continuation_enter");
1173   }
1174 
1175   oop_maps->add_gc_map(__ pc() - start, map);
1176   __ post_call_nop();
1177 
1178   __ b(exit);
1179 
1180   __ bind(call_thaw);
1181 
1182   __ rt_call(CAST_FROM_FN_PTR(address, StubRoutines::cont_thaw()));
1183   oop_maps->add_gc_map(__ pc() - start, map->deep_copy());
1184   ContinuationEntry::_return_pc_offset = __ pc() - start;
1185   __ post_call_nop();
1186 
1187   __ bind(exit);
1188   continuation_enter_cleanup(masm);
1189   __ leave();
1190   __ ret(lr);
1191 
1192   /// exception handling
1193 
1194   exception_offset = __ pc() - start;
1195   {
1196       __ mov(r19, r0); // save return value contaning the exception oop in callee-saved R19
1197 
1198       continuation_enter_cleanup(masm);
1199 
1200       __ ldr(c_rarg1, Address(rfp, wordSize)); // return address
1201       __ authenticate_return_address(c_rarg1);
1202       __ call_VM_leaf(CAST_FROM_FN_PTR(address, SharedRuntime::exception_handler_for_return_address), rthread, c_rarg1);
1203 
1204       // see OptoRuntime::generate_exception_blob: r0 -- exception oop, r3 -- exception pc
1205 
1206       __ mov(r1, r0); // the exception handler
1207       __ mov(r0, r19); // restore return value contaning the exception oop
1208       __ verify_oop(r0);
1209 
1210       __ leave();
1211       __ mov(r3, lr);
1212       __ br(r1); // the exception handler
1213   }
1214 
1215   address stub = CompiledDirectCall::emit_to_interp_stub(masm, tr_call);
1216   if (stub == nullptr) {
1217     fatal("CodeCache is full at gen_continuation_enter");
1218   }
1219 }
1220 
1221 static void gen_continuation_yield(MacroAssembler* masm,
1222                                    const methodHandle& method,
1223                                    const BasicType* sig_bt,
1224                                    const VMRegPair* regs,
1225                                    OopMapSet* oop_maps,
1226                                    int& frame_complete,
1227                                    int& stack_slots,
1228                                    int& compiled_entry_offset) {
1229     enum layout {
1230       rfp_off1,
1231       rfp_off2,
1232       lr_off,
1233       lr_off2,
1234       framesize // inclusive of return address
1235     };
1236     // assert(is_even(framesize/2), "sp not 16-byte aligned");
1237     stack_slots = framesize /  VMRegImpl::slots_per_word;
1238     assert(stack_slots == 2, "recheck layout");
1239 
1240     address start = __ pc();
1241 
1242     compiled_entry_offset = __ pc() - start;
1243     __ enter();
1244 
1245     __ mov(c_rarg1, sp);
1246 
1247     frame_complete = __ pc() - start;
1248     address the_pc = __ pc();
1249 
1250     __ post_call_nop(); // this must be exactly after the pc value that is pushed into the frame info, we use this nop for fast CodeBlob lookup
1251 
1252     __ mov(c_rarg0, rthread);
1253     __ set_last_Java_frame(sp, rfp, the_pc, rscratch1);
1254     __ call_VM_leaf(Continuation::freeze_entry(), 2);
1255     __ reset_last_Java_frame(true);
1256 
1257     Label pinned;
1258 
1259     __ cbnz(r0, pinned);
1260 
1261     // We've succeeded, set sp to the ContinuationEntry
1262     __ ldr(rscratch1, Address(rthread, JavaThread::cont_entry_offset()));
1263     __ mov(sp, rscratch1);
1264     continuation_enter_cleanup(masm);
1265 
1266     __ bind(pinned); // pinned -- return to caller
1267 
1268     // handle pending exception thrown by freeze
1269     __ ldr(rscratch1, Address(rthread, in_bytes(Thread::pending_exception_offset())));
1270     Label ok;
1271     __ cbz(rscratch1, ok);
1272     __ leave();
1273     __ lea(rscratch1, RuntimeAddress(StubRoutines::forward_exception_entry()));
1274     __ br(rscratch1);
1275     __ bind(ok);
1276 
1277     __ leave();
1278     __ ret(lr);
1279 
1280     OopMap* map = new OopMap(framesize, 1);
1281     oop_maps->add_gc_map(the_pc - start, map);
1282 }
1283 
1284 static void gen_special_dispatch(MacroAssembler* masm,
1285                                  const methodHandle& method,
1286                                  const BasicType* sig_bt,
1287                                  const VMRegPair* regs) {
1288   verify_oop_args(masm, method, sig_bt, regs);
1289   vmIntrinsics::ID iid = method->intrinsic_id();
1290 
1291   // Now write the args into the outgoing interpreter space
1292   bool     has_receiver   = false;
1293   Register receiver_reg   = noreg;
1294   int      member_arg_pos = -1;
1295   Register member_reg     = noreg;
1296   int      ref_kind       = MethodHandles::signature_polymorphic_intrinsic_ref_kind(iid);
1297   if (ref_kind != 0) {
1298     member_arg_pos = method->size_of_parameters() - 1;  // trailing MemberName argument
1299     member_reg = r19;  // known to be free at this point
1300     has_receiver = MethodHandles::ref_kind_has_receiver(ref_kind);
1301   } else if (iid == vmIntrinsics::_invokeBasic) {
1302     has_receiver = true;
1303   } else if (iid == vmIntrinsics::_linkToNative) {
1304     member_arg_pos = method->size_of_parameters() - 1;  // trailing NativeEntryPoint argument
1305     member_reg = r19;  // known to be free at this point
1306   } else {
1307     fatal("unexpected intrinsic id %d", vmIntrinsics::as_int(iid));
1308   }
1309 
1310   if (member_reg != noreg) {
1311     // Load the member_arg into register, if necessary.
1312     SharedRuntime::check_member_name_argument_is_last_argument(method, sig_bt, regs);
1313     VMReg r = regs[member_arg_pos].first();
1314     if (r->is_stack()) {
1315       __ ldr(member_reg, Address(sp, r->reg2stack() * VMRegImpl::stack_slot_size));
1316     } else {
1317       // no data motion is needed
1318       member_reg = r->as_Register();
1319     }
1320   }
1321 
1322   if (has_receiver) {
1323     // Make sure the receiver is loaded into a register.
1324     assert(method->size_of_parameters() > 0, "oob");
1325     assert(sig_bt[0] == T_OBJECT, "receiver argument must be an object");
1326     VMReg r = regs[0].first();
1327     assert(r->is_valid(), "bad receiver arg");
1328     if (r->is_stack()) {
1329       // Porting note:  This assumes that compiled calling conventions always
1330       // pass the receiver oop in a register.  If this is not true on some
1331       // platform, pick a temp and load the receiver from stack.
1332       fatal("receiver always in a register");
1333       receiver_reg = r2;  // known to be free at this point
1334       __ ldr(receiver_reg, Address(sp, r->reg2stack() * VMRegImpl::stack_slot_size));
1335     } else {
1336       // no data motion is needed
1337       receiver_reg = r->as_Register();
1338     }
1339   }
1340 
1341   // Figure out which address we are really jumping to:
1342   MethodHandles::generate_method_handle_dispatch(masm, iid,
1343                                                  receiver_reg, member_reg, /*for_compiler_entry:*/ true);
1344 }
1345 
1346 // ---------------------------------------------------------------------------
1347 // Generate a native wrapper for a given method.  The method takes arguments
1348 // in the Java compiled code convention, marshals them to the native
1349 // convention (handlizes oops, etc), transitions to native, makes the call,
1350 // returns to java state (possibly blocking), unhandlizes any result and
1351 // returns.
1352 //
1353 // Critical native functions are a shorthand for the use of
1354 // GetPrimtiveArrayCritical and disallow the use of any other JNI
1355 // functions.  The wrapper is expected to unpack the arguments before
1356 // passing them to the callee. Critical native functions leave the state _in_Java,
1357 // since they block out GC.
1358 // Some other parts of JNI setup are skipped like the tear down of the JNI handle
1359 // block and the check for pending exceptions it's impossible for them
1360 // to be thrown.
1361 //
1362 nmethod* SharedRuntime::generate_native_wrapper(MacroAssembler* masm,
1363                                                 const methodHandle& method,
1364                                                 int compile_id,
1365                                                 BasicType* in_sig_bt,
1366                                                 VMRegPair* in_regs,
1367                                                 BasicType ret_type) {
1368   if (method->is_continuation_native_intrinsic()) {
1369     int exception_offset = -1;
1370     OopMapSet* oop_maps = new OopMapSet();
1371     int frame_complete = -1;
1372     int stack_slots = -1;
1373     int interpreted_entry_offset = -1;
1374     int vep_offset = -1;
1375     if (method->is_continuation_enter_intrinsic()) {
1376       gen_continuation_enter(masm,
1377                              method,
1378                              in_sig_bt,
1379                              in_regs,
1380                              exception_offset,
1381                              oop_maps,
1382                              frame_complete,
1383                              stack_slots,
1384                              interpreted_entry_offset,
1385                              vep_offset);
1386     } else if (method->is_continuation_yield_intrinsic()) {
1387       gen_continuation_yield(masm,
1388                              method,
1389                              in_sig_bt,
1390                              in_regs,
1391                              oop_maps,
1392                              frame_complete,
1393                              stack_slots,
1394                              vep_offset);
1395     } else {
1396       guarantee(false, "Unknown Continuation native intrinsic");
1397     }
1398 
1399 #ifdef ASSERT
1400     if (method->is_continuation_enter_intrinsic()) {
1401       assert(interpreted_entry_offset != -1, "Must be set");
1402       assert(exception_offset != -1,         "Must be set");
1403     } else {
1404       assert(interpreted_entry_offset == -1, "Must be unset");
1405       assert(exception_offset == -1,         "Must be unset");
1406     }
1407     assert(frame_complete != -1,    "Must be set");
1408     assert(stack_slots != -1,       "Must be set");
1409     assert(vep_offset != -1,        "Must be set");
1410 #endif
1411 
1412     __ flush();
1413     nmethod* nm = nmethod::new_native_nmethod(method,
1414                                               compile_id,
1415                                               masm->code(),
1416                                               vep_offset,
1417                                               frame_complete,
1418                                               stack_slots,
1419                                               in_ByteSize(-1),
1420                                               in_ByteSize(-1),
1421                                               oop_maps,
1422                                               exception_offset);
1423     if (nm == nullptr) return nm;
1424     if (method->is_continuation_enter_intrinsic()) {
1425       ContinuationEntry::set_enter_code(nm, interpreted_entry_offset);
1426     } else if (method->is_continuation_yield_intrinsic()) {
1427       _cont_doYield_stub = nm;
1428     } else {
1429       guarantee(false, "Unknown Continuation native intrinsic");
1430     }
1431     return nm;
1432   }
1433 
1434   if (method->is_method_handle_intrinsic()) {
1435     vmIntrinsics::ID iid = method->intrinsic_id();
1436     intptr_t start = (intptr_t)__ pc();
1437     int vep_offset = ((intptr_t)__ pc()) - start;
1438 
1439     // First instruction must be a nop as it may need to be patched on deoptimisation
1440     __ nop();
1441     gen_special_dispatch(masm,
1442                          method,
1443                          in_sig_bt,
1444                          in_regs);
1445     int frame_complete = ((intptr_t)__ pc()) - start;  // not complete, period
1446     __ flush();
1447     int stack_slots = SharedRuntime::out_preserve_stack_slots();  // no out slots at all, actually
1448     return nmethod::new_native_nmethod(method,
1449                                        compile_id,
1450                                        masm->code(),
1451                                        vep_offset,
1452                                        frame_complete,
1453                                        stack_slots / VMRegImpl::slots_per_word,
1454                                        in_ByteSize(-1),
1455                                        in_ByteSize(-1),
1456                                        nullptr);
1457   }
1458   address native_func = method->native_function();
1459   assert(native_func != nullptr, "must have function");
1460 
1461   // An OopMap for lock (and class if static)
1462   OopMapSet *oop_maps = new OopMapSet();
1463   intptr_t start = (intptr_t)__ pc();
1464 
1465   // We have received a description of where all the java arg are located
1466   // on entry to the wrapper. We need to convert these args to where
1467   // the jni function will expect them. To figure out where they go
1468   // we convert the java signature to a C signature by inserting
1469   // the hidden arguments as arg[0] and possibly arg[1] (static method)
1470 
1471   const int total_in_args = method->size_of_parameters();
1472   int total_c_args = total_in_args + (method->is_static() ? 2 : 1);
1473 
1474   BasicType* out_sig_bt = NEW_RESOURCE_ARRAY(BasicType, total_c_args);
1475   VMRegPair* out_regs   = NEW_RESOURCE_ARRAY(VMRegPair, total_c_args);
1476   BasicType* in_elem_bt = nullptr;
1477 
1478   int argc = 0;
1479   out_sig_bt[argc++] = T_ADDRESS;
1480   if (method->is_static()) {
1481     out_sig_bt[argc++] = T_OBJECT;
1482   }
1483 
1484   for (int i = 0; i < total_in_args ; i++ ) {
1485     out_sig_bt[argc++] = in_sig_bt[i];
1486   }
1487 
1488   // Now figure out where the args must be stored and how much stack space
1489   // they require.
1490   int out_arg_slots;
1491   out_arg_slots = c_calling_convention_priv(out_sig_bt, out_regs, total_c_args);
1492 
1493   if (out_arg_slots < 0) {
1494     return nullptr;
1495   }
1496 
1497   // Compute framesize for the wrapper.  We need to handlize all oops in
1498   // incoming registers
1499 
1500   // Calculate the total number of stack slots we will need.
1501 
1502   // First count the abi requirement plus all of the outgoing args
1503   int stack_slots = SharedRuntime::out_preserve_stack_slots() + out_arg_slots;
1504 
1505   // Now the space for the inbound oop handle area
1506   int total_save_slots = 8 * VMRegImpl::slots_per_word;  // 8 arguments passed in registers
1507 
1508   int oop_handle_offset = stack_slots;
1509   stack_slots += total_save_slots;
1510 
1511   // Now any space we need for handlizing a klass if static method
1512 
1513   int klass_slot_offset = 0;
1514   int klass_offset = -1;
1515   int lock_slot_offset = 0;
1516   bool is_static = false;
1517 
1518   if (method->is_static()) {
1519     klass_slot_offset = stack_slots;
1520     stack_slots += VMRegImpl::slots_per_word;
1521     klass_offset = klass_slot_offset * VMRegImpl::stack_slot_size;
1522     is_static = true;
1523   }
1524 
1525   // Plus a lock if needed
1526 
1527   if (method->is_synchronized()) {
1528     lock_slot_offset = stack_slots;
1529     stack_slots += VMRegImpl::slots_per_word;
1530   }
1531 
1532   // Now a place (+2) to save return values or temp during shuffling
1533   // + 4 for return address (which we own) and saved rfp
1534   stack_slots += 6;
1535 
1536   // Ok The space we have allocated will look like:
1537   //
1538   //
1539   // FP-> |                     |
1540   //      |---------------------|
1541   //      | 2 slots for moves   |
1542   //      |---------------------|
1543   //      | lock box (if sync)  |
1544   //      |---------------------| <- lock_slot_offset
1545   //      | klass (if static)   |
1546   //      |---------------------| <- klass_slot_offset
1547   //      | oopHandle area      |
1548   //      |---------------------| <- oop_handle_offset (8 java arg registers)
1549   //      | outbound memory     |
1550   //      | based arguments     |
1551   //      |                     |
1552   //      |---------------------|
1553   //      |                     |
1554   // SP-> | out_preserved_slots |
1555   //
1556   //
1557 
1558 
1559   // Now compute actual number of stack words we need rounding to make
1560   // stack properly aligned.
1561   stack_slots = align_up(stack_slots, StackAlignmentInSlots);
1562 
1563   int stack_size = stack_slots * VMRegImpl::stack_slot_size;
1564 
1565   // First thing make an ic check to see if we should even be here
1566 
1567   // We are free to use all registers as temps without saving them and
1568   // restoring them except rfp. rfp is the only callee save register
1569   // as far as the interpreter and the compiler(s) are concerned.
1570 
1571   const Register receiver = j_rarg0;
1572 
1573   Label exception_pending;
1574 
1575   assert_different_registers(receiver, rscratch1);
1576   __ verify_oop(receiver);
1577   __ ic_check(8 /* end_alignment */);
1578 
1579   // Verified entry point must be aligned
1580   int vep_offset = ((intptr_t)__ pc()) - start;
1581 
1582   // If we have to make this method not-entrant we'll overwrite its
1583   // first instruction with a jump.  For this action to be legal we
1584   // must ensure that this first instruction is a B, BL, NOP, BKPT,
1585   // SVC, HVC, or SMC.  Make it a NOP.
1586   __ nop();
1587 
1588   if (VM_Version::supports_fast_class_init_checks() && method->needs_clinit_barrier()) {
1589     Label L_skip_barrier;
1590     __ mov_metadata(rscratch2, method->method_holder()); // InstanceKlass*
1591     __ clinit_barrier(rscratch2, rscratch1, &L_skip_barrier);
1592     __ far_jump(RuntimeAddress(SharedRuntime::get_handle_wrong_method_stub()));
1593 
1594     __ bind(L_skip_barrier);
1595   }
1596 
1597   // Generate stack overflow check
1598   __ bang_stack_with_offset(checked_cast<int>(StackOverflow::stack_shadow_zone_size()));
1599 
1600   // Generate a new frame for the wrapper.
1601   __ enter();
1602   // -2 because return address is already present and so is saved rfp
1603   __ sub(sp, sp, stack_size - 2*wordSize);
1604 
1605   BarrierSetAssembler* bs = BarrierSet::barrier_set()->barrier_set_assembler();
1606   bs->nmethod_entry_barrier(masm, nullptr /* slow_path */, nullptr /* continuation */, nullptr /* guard */);
1607 
1608   // Frame is now completed as far as size and linkage.
1609   int frame_complete = ((intptr_t)__ pc()) - start;
1610 
1611   // We use r20 as the oop handle for the receiver/klass
1612   // It is callee save so it survives the call to native
1613 
1614   const Register oop_handle_reg = r20;
1615 
1616   //
1617   // We immediately shuffle the arguments so that any vm call we have to
1618   // make from here on out (sync slow path, jvmti, etc.) we will have
1619   // captured the oops from our caller and have a valid oopMap for
1620   // them.
1621 
1622   // -----------------
1623   // The Grand Shuffle
1624 
1625   // The Java calling convention is either equal (linux) or denser (win64) than the
1626   // c calling convention. However the because of the jni_env argument the c calling
1627   // convention always has at least one more (and two for static) arguments than Java.
1628   // Therefore if we move the args from java -> c backwards then we will never have
1629   // a register->register conflict and we don't have to build a dependency graph
1630   // and figure out how to break any cycles.
1631   //
1632 
1633   // Record esp-based slot for receiver on stack for non-static methods
1634   int receiver_offset = -1;
1635 
1636   // This is a trick. We double the stack slots so we can claim
1637   // the oops in the caller's frame. Since we are sure to have
1638   // more args than the caller doubling is enough to make
1639   // sure we can capture all the incoming oop args from the
1640   // caller.
1641   //
1642   OopMap* map = new OopMap(stack_slots * 2, 0 /* arg_slots*/);
1643 
1644   // Mark location of rfp (someday)
1645   // map->set_callee_saved(VMRegImpl::stack2reg( stack_slots - 2), stack_slots * 2, 0, vmreg(rfp));
1646 
1647 
1648   int float_args = 0;
1649   int int_args = 0;
1650 
1651 #ifdef ASSERT
1652   bool reg_destroyed[Register::number_of_registers];
1653   bool freg_destroyed[FloatRegister::number_of_registers];
1654   for ( int r = 0 ; r < Register::number_of_registers ; r++ ) {
1655     reg_destroyed[r] = false;
1656   }
1657   for ( int f = 0 ; f < FloatRegister::number_of_registers ; f++ ) {
1658     freg_destroyed[f] = false;
1659   }
1660 
1661 #endif /* ASSERT */
1662 
1663   // For JNI natives the incoming and outgoing registers are offset upwards.
1664   GrowableArray<int> arg_order(2 * total_in_args);
1665   VMRegPair tmp_vmreg;
1666   tmp_vmreg.set2(r19->as_VMReg());
1667 
1668   for (int i = total_in_args - 1, c_arg = total_c_args - 1; i >= 0; i--, c_arg--) {
1669     arg_order.push(i);
1670     arg_order.push(c_arg);
1671   }
1672 
1673   int temploc = -1;
1674   for (int ai = 0; ai < arg_order.length(); ai += 2) {
1675     int i = arg_order.at(ai);
1676     int c_arg = arg_order.at(ai + 1);
1677     __ block_comment(err_msg("move %d -> %d", i, c_arg));
1678     assert(c_arg != -1 && i != -1, "wrong order");
1679 #ifdef ASSERT
1680     if (in_regs[i].first()->is_Register()) {
1681       assert(!reg_destroyed[in_regs[i].first()->as_Register()->encoding()], "destroyed reg!");
1682     } else if (in_regs[i].first()->is_FloatRegister()) {
1683       assert(!freg_destroyed[in_regs[i].first()->as_FloatRegister()->encoding()], "destroyed reg!");
1684     }
1685     if (out_regs[c_arg].first()->is_Register()) {
1686       reg_destroyed[out_regs[c_arg].first()->as_Register()->encoding()] = true;
1687     } else if (out_regs[c_arg].first()->is_FloatRegister()) {
1688       freg_destroyed[out_regs[c_arg].first()->as_FloatRegister()->encoding()] = true;
1689     }
1690 #endif /* ASSERT */
1691     switch (in_sig_bt[i]) {
1692       case T_ARRAY:
1693       case T_OBJECT:
1694         __ object_move(map, oop_handle_offset, stack_slots, in_regs[i], out_regs[c_arg],
1695                        ((i == 0) && (!is_static)),
1696                        &receiver_offset);
1697         int_args++;
1698         break;
1699       case T_VOID:
1700         break;
1701 
1702       case T_FLOAT:
1703         __ float_move(in_regs[i], out_regs[c_arg]);
1704         float_args++;
1705         break;
1706 
1707       case T_DOUBLE:
1708         assert( i + 1 < total_in_args &&
1709                 in_sig_bt[i + 1] == T_VOID &&
1710                 out_sig_bt[c_arg+1] == T_VOID, "bad arg list");
1711         __ double_move(in_regs[i], out_regs[c_arg]);
1712         float_args++;
1713         break;
1714 
1715       case T_LONG :
1716         __ long_move(in_regs[i], out_regs[c_arg]);
1717         int_args++;
1718         break;
1719 
1720       case T_ADDRESS: assert(false, "found T_ADDRESS in java args");
1721 
1722       default:
1723         __ move32_64(in_regs[i], out_regs[c_arg]);
1724         int_args++;
1725     }
1726   }
1727 
1728   // point c_arg at the first arg that is already loaded in case we
1729   // need to spill before we call out
1730   int c_arg = total_c_args - total_in_args;
1731 
1732   // Pre-load a static method's oop into c_rarg1.
1733   if (method->is_static()) {
1734 
1735     //  load oop into a register
1736     __ movoop(c_rarg1,
1737               JNIHandles::make_local(method->method_holder()->java_mirror()));
1738 
1739     // Now handlize the static class mirror it's known not-null.
1740     __ str(c_rarg1, Address(sp, klass_offset));
1741     map->set_oop(VMRegImpl::stack2reg(klass_slot_offset));
1742 
1743     // Now get the handle
1744     __ lea(c_rarg1, Address(sp, klass_offset));
1745     // and protect the arg if we must spill
1746     c_arg--;
1747   }
1748 
1749   // Change state to native (we save the return address in the thread, since it might not
1750   // be pushed on the stack when we do a stack traversal).
1751   // We use the same pc/oopMap repeatedly when we call out
1752 
1753   Label native_return;
1754   __ set_last_Java_frame(sp, noreg, native_return, rscratch1);
1755 
1756   Label dtrace_method_entry, dtrace_method_entry_done;
1757   if (DTraceMethodProbes) {
1758     __ b(dtrace_method_entry);
1759     __ bind(dtrace_method_entry_done);
1760   }
1761 
1762   // RedefineClasses() tracing support for obsolete method entry
1763   if (log_is_enabled(Trace, redefine, class, obsolete)) {
1764     // protect the args we've loaded
1765     save_args(masm, total_c_args, c_arg, out_regs);
1766     __ mov_metadata(c_rarg1, method());
1767     __ call_VM_leaf(
1768       CAST_FROM_FN_PTR(address, SharedRuntime::rc_trace_method_entry),
1769       rthread, c_rarg1);
1770     restore_args(masm, total_c_args, c_arg, out_regs);
1771   }
1772 
1773   // Lock a synchronized method
1774 
1775   // Register definitions used by locking and unlocking
1776 
1777   const Register swap_reg = r0;
1778   const Register obj_reg  = r19;  // Will contain the oop
1779   const Register lock_reg = r13;  // Address of compiler lock object (BasicLock)
1780   const Register old_hdr  = r13;  // value of old header at unlock time
1781   const Register lock_tmp = r14;  // Temporary used by lightweight_lock/unlock
1782   const Register tmp = lr;
1783 
1784   Label slow_path_lock;
1785   Label lock_done;
1786 
1787   if (method->is_synchronized()) {
1788     Label count;
1789     const int mark_word_offset = BasicLock::displaced_header_offset_in_bytes();
1790 
1791     // Get the handle (the 2nd argument)
1792     __ mov(oop_handle_reg, c_rarg1);
1793 
1794     // Get address of the box
1795 
1796     __ lea(lock_reg, Address(sp, lock_slot_offset * VMRegImpl::stack_slot_size));
1797 
1798     // Load the oop from the handle
1799     __ ldr(obj_reg, Address(oop_handle_reg, 0));
1800 
1801     if (LockingMode == LM_MONITOR) {
1802       __ b(slow_path_lock);
1803     } else if (LockingMode == LM_LEGACY) {
1804       // Load (object->mark() | 1) into swap_reg %r0
1805       __ ldr(rscratch1, Address(obj_reg, oopDesc::mark_offset_in_bytes()));
1806       __ orr(swap_reg, rscratch1, 1);
1807 
1808       // Save (object->mark() | 1) into BasicLock's displaced header
1809       __ str(swap_reg, Address(lock_reg, mark_word_offset));
1810 
1811       // src -> dest iff dest == r0 else r0 <- dest
1812       __ cmpxchg_obj_header(r0, lock_reg, obj_reg, rscratch1, count, /*fallthrough*/nullptr);
1813 
1814       // Hmm should this move to the slow path code area???
1815 
1816       // Test if the oopMark is an obvious stack pointer, i.e.,
1817       //  1) (mark & 3) == 0, and
1818       //  2) sp <= mark < mark + os::pagesize()
1819       // These 3 tests can be done by evaluating the following
1820       // expression: ((mark - sp) & (3 - os::vm_page_size())),
1821       // assuming both stack pointer and pagesize have their
1822       // least significant 2 bits clear.
1823       // NOTE: the oopMark is in swap_reg %r0 as the result of cmpxchg
1824 
1825       __ sub(swap_reg, sp, swap_reg);
1826       __ neg(swap_reg, swap_reg);
1827       __ ands(swap_reg, swap_reg, 3 - (int)os::vm_page_size());
1828 
1829       // Save the test result, for recursive case, the result is zero
1830       __ str(swap_reg, Address(lock_reg, mark_word_offset));
1831       __ br(Assembler::NE, slow_path_lock);
1832     } else {
1833       assert(LockingMode == LM_LIGHTWEIGHT, "must be");
1834       __ lightweight_lock(obj_reg, swap_reg, tmp, lock_tmp, slow_path_lock);
1835     }
1836     __ bind(count);
1837     __ increment(Address(rthread, JavaThread::held_monitor_count_offset()));
1838 
1839     // Slow path will re-enter here
1840     __ bind(lock_done);
1841   }
1842 
1843 
1844   // Finally just about ready to make the JNI call
1845 
1846   // get JNIEnv* which is first argument to native
1847   __ lea(c_rarg0, Address(rthread, in_bytes(JavaThread::jni_environment_offset())));
1848 
1849   // Now set thread in native
1850   __ mov(rscratch1, _thread_in_native);
1851   __ lea(rscratch2, Address(rthread, JavaThread::thread_state_offset()));
1852   __ stlrw(rscratch1, rscratch2);
1853 
1854   __ rt_call(native_func);
1855 
1856   __ bind(native_return);
1857 
1858   intptr_t return_pc = (intptr_t) __ pc();
1859   oop_maps->add_gc_map(return_pc - start, map);
1860 
1861   // Verify or restore cpu control state after JNI call
1862   __ restore_cpu_control_state_after_jni(rscratch1, rscratch2);
1863 
1864   // Unpack native results.
1865   switch (ret_type) {
1866   case T_BOOLEAN: __ c2bool(r0);                     break;
1867   case T_CHAR   : __ ubfx(r0, r0, 0, 16);            break;
1868   case T_BYTE   : __ sbfx(r0, r0, 0, 8);             break;
1869   case T_SHORT  : __ sbfx(r0, r0, 0, 16);            break;
1870   case T_INT    : __ sbfx(r0, r0, 0, 32);            break;
1871   case T_DOUBLE :
1872   case T_FLOAT  :
1873     // Result is in v0 we'll save as needed
1874     break;
1875   case T_ARRAY:                 // Really a handle
1876   case T_OBJECT:                // Really a handle
1877       break; // can't de-handlize until after safepoint check
1878   case T_VOID: break;
1879   case T_LONG: break;
1880   default       : ShouldNotReachHere();
1881   }
1882 
1883   Label safepoint_in_progress, safepoint_in_progress_done;
1884   Label after_transition;
1885 
1886   // Switch thread to "native transition" state before reading the synchronization state.
1887   // This additional state is necessary because reading and testing the synchronization
1888   // state is not atomic w.r.t. GC, as this scenario demonstrates:
1889   //     Java thread A, in _thread_in_native state, loads _not_synchronized and is preempted.
1890   //     VM thread changes sync state to synchronizing and suspends threads for GC.
1891   //     Thread A is resumed to finish this native method, but doesn't block here since it
1892   //     didn't see any synchronization is progress, and escapes.
1893   __ mov(rscratch1, _thread_in_native_trans);
1894 
1895   __ strw(rscratch1, Address(rthread, JavaThread::thread_state_offset()));
1896 
1897   // Force this write out before the read below
1898   if (!UseSystemMemoryBarrier) {
1899     __ dmb(Assembler::ISH);
1900   }
1901 
1902   __ verify_sve_vector_length();
1903 
1904   // Check for safepoint operation in progress and/or pending suspend requests.
1905   {
1906     // We need an acquire here to ensure that any subsequent load of the
1907     // global SafepointSynchronize::_state flag is ordered after this load
1908     // of the thread-local polling word.  We don't want this poll to
1909     // return false (i.e. not safepointing) and a later poll of the global
1910     // SafepointSynchronize::_state spuriously to return true.
1911     //
1912     // This is to avoid a race when we're in a native->Java transition
1913     // racing the code which wakes up from a safepoint.
1914 
1915     __ safepoint_poll(safepoint_in_progress, true /* at_return */, true /* acquire */, false /* in_nmethod */);
1916     __ ldrw(rscratch1, Address(rthread, JavaThread::suspend_flags_offset()));
1917     __ cbnzw(rscratch1, safepoint_in_progress);
1918     __ bind(safepoint_in_progress_done);
1919   }
1920 
1921   // change thread state
1922   __ mov(rscratch1, _thread_in_Java);
1923   __ lea(rscratch2, Address(rthread, JavaThread::thread_state_offset()));
1924   __ stlrw(rscratch1, rscratch2);
1925   __ bind(after_transition);
1926 
1927   Label reguard;
1928   Label reguard_done;
1929   __ ldrb(rscratch1, Address(rthread, JavaThread::stack_guard_state_offset()));
1930   __ cmpw(rscratch1, StackOverflow::stack_guard_yellow_reserved_disabled);
1931   __ br(Assembler::EQ, reguard);
1932   __ bind(reguard_done);
1933 
1934   // native result if any is live
1935 
1936   // Unlock
1937   Label unlock_done;
1938   Label slow_path_unlock;
1939   if (method->is_synchronized()) {
1940 
1941     // Get locked oop from the handle we passed to jni
1942     __ ldr(obj_reg, Address(oop_handle_reg, 0));
1943 
1944     Label done, not_recursive;
1945 
1946     if (LockingMode == LM_LEGACY) {
1947       // Simple recursive lock?
1948       __ ldr(rscratch1, Address(sp, lock_slot_offset * VMRegImpl::stack_slot_size));
1949       __ cbnz(rscratch1, not_recursive);
1950       __ decrement(Address(rthread, JavaThread::held_monitor_count_offset()));
1951       __ b(done);
1952     }
1953 
1954     __ bind(not_recursive);
1955 
1956     // Must save r0 if if it is live now because cmpxchg must use it
1957     if (ret_type != T_FLOAT && ret_type != T_DOUBLE && ret_type != T_VOID) {
1958       save_native_result(masm, ret_type, stack_slots);
1959     }
1960 
1961     if (LockingMode == LM_MONITOR) {
1962       __ b(slow_path_unlock);
1963     } else if (LockingMode == LM_LEGACY) {
1964       // get address of the stack lock
1965       __ lea(r0, Address(sp, lock_slot_offset * VMRegImpl::stack_slot_size));
1966       //  get old displaced header
1967       __ ldr(old_hdr, Address(r0, 0));
1968 
1969       // Atomic swap old header if oop still contains the stack lock
1970       Label count;
1971       __ cmpxchg_obj_header(r0, old_hdr, obj_reg, rscratch1, count, &slow_path_unlock);
1972       __ bind(count);
1973       __ decrement(Address(rthread, JavaThread::held_monitor_count_offset()));
1974     } else {
1975       assert(LockingMode == LM_LIGHTWEIGHT, "");
1976       __ lightweight_unlock(obj_reg, old_hdr, swap_reg, lock_tmp, slow_path_unlock);
1977       __ decrement(Address(rthread, JavaThread::held_monitor_count_offset()));
1978     }
1979 
1980     // slow path re-enters here
1981     __ bind(unlock_done);
1982     if (ret_type != T_FLOAT && ret_type != T_DOUBLE && ret_type != T_VOID) {
1983       restore_native_result(masm, ret_type, stack_slots);
1984     }
1985 
1986     __ bind(done);
1987   }
1988 
1989   Label dtrace_method_exit, dtrace_method_exit_done;
1990   if (DTraceMethodProbes) {
1991     __ b(dtrace_method_exit);
1992     __ bind(dtrace_method_exit_done);
1993   }
1994 
1995   __ reset_last_Java_frame(false);
1996 
1997   // Unbox oop result, e.g. JNIHandles::resolve result.
1998   if (is_reference_type(ret_type)) {
1999     __ resolve_jobject(r0, r1, r2);
2000   }
2001 
2002   if (CheckJNICalls) {
2003     // clear_pending_jni_exception_check
2004     __ str(zr, Address(rthread, JavaThread::pending_jni_exception_check_fn_offset()));
2005   }
2006 
2007   // reset handle block
2008   __ ldr(r2, Address(rthread, JavaThread::active_handles_offset()));
2009   __ str(zr, Address(r2, JNIHandleBlock::top_offset()));
2010 
2011   __ leave();
2012 
2013   // Any exception pending?
2014   __ ldr(rscratch1, Address(rthread, in_bytes(Thread::pending_exception_offset())));
2015   __ cbnz(rscratch1, exception_pending);
2016 
2017   // We're done
2018   __ ret(lr);
2019 
2020   // Unexpected paths are out of line and go here
2021 
2022   // forward the exception
2023   __ bind(exception_pending);
2024 
2025   // and forward the exception
2026   __ far_jump(RuntimeAddress(StubRoutines::forward_exception_entry()));
2027 
2028   // Slow path locking & unlocking
2029   if (method->is_synchronized()) {
2030 
2031     __ block_comment("Slow path lock {");
2032     __ bind(slow_path_lock);
2033 
2034     // has last_Java_frame setup. No exceptions so do vanilla call not call_VM
2035     // args are (oop obj, BasicLock* lock, JavaThread* thread)
2036 
2037     // protect the args we've loaded
2038     save_args(masm, total_c_args, c_arg, out_regs);
2039 
2040     __ mov(c_rarg0, obj_reg);
2041     __ mov(c_rarg1, lock_reg);
2042     __ mov(c_rarg2, rthread);
2043 
2044     // Not a leaf but we have last_Java_frame setup as we want
2045     __ call_VM_leaf(CAST_FROM_FN_PTR(address, SharedRuntime::complete_monitor_locking_C), 3);
2046     restore_args(masm, total_c_args, c_arg, out_regs);
2047 
2048 #ifdef ASSERT
2049     { Label L;
2050       __ ldr(rscratch1, Address(rthread, in_bytes(Thread::pending_exception_offset())));
2051       __ cbz(rscratch1, L);
2052       __ stop("no pending exception allowed on exit from monitorenter");
2053       __ bind(L);
2054     }
2055 #endif
2056     __ b(lock_done);
2057 
2058     __ block_comment("} Slow path lock");
2059 
2060     __ block_comment("Slow path unlock {");
2061     __ bind(slow_path_unlock);
2062 
2063     // If we haven't already saved the native result we must save it now as xmm registers
2064     // are still exposed.
2065 
2066     if (ret_type == T_FLOAT || ret_type == T_DOUBLE ) {
2067       save_native_result(masm, ret_type, stack_slots);
2068     }
2069 
2070     __ mov(c_rarg2, rthread);
2071     __ lea(c_rarg1, Address(sp, lock_slot_offset * VMRegImpl::stack_slot_size));
2072     __ mov(c_rarg0, obj_reg);
2073 
2074     // Save pending exception around call to VM (which contains an EXCEPTION_MARK)
2075     // NOTE that obj_reg == r19 currently
2076     __ ldr(r19, Address(rthread, in_bytes(Thread::pending_exception_offset())));
2077     __ str(zr, Address(rthread, in_bytes(Thread::pending_exception_offset())));
2078 
2079     __ rt_call(CAST_FROM_FN_PTR(address, SharedRuntime::complete_monitor_unlocking_C));
2080 
2081 #ifdef ASSERT
2082     {
2083       Label L;
2084       __ ldr(rscratch1, Address(rthread, in_bytes(Thread::pending_exception_offset())));
2085       __ cbz(rscratch1, L);
2086       __ stop("no pending exception allowed on exit complete_monitor_unlocking_C");
2087       __ bind(L);
2088     }
2089 #endif /* ASSERT */
2090 
2091     __ str(r19, Address(rthread, in_bytes(Thread::pending_exception_offset())));
2092 
2093     if (ret_type == T_FLOAT || ret_type == T_DOUBLE ) {
2094       restore_native_result(masm, ret_type, stack_slots);
2095     }
2096     __ b(unlock_done);
2097 
2098     __ block_comment("} Slow path unlock");
2099 
2100   } // synchronized
2101 
2102   // SLOW PATH Reguard the stack if needed
2103 
2104   __ bind(reguard);
2105   save_native_result(masm, ret_type, stack_slots);
2106   __ rt_call(CAST_FROM_FN_PTR(address, SharedRuntime::reguard_yellow_pages));
2107   restore_native_result(masm, ret_type, stack_slots);
2108   // and continue
2109   __ b(reguard_done);
2110 
2111   // SLOW PATH safepoint
2112   {
2113     __ block_comment("safepoint {");
2114     __ bind(safepoint_in_progress);
2115 
2116     // Don't use call_VM as it will see a possible pending exception and forward it
2117     // and never return here preventing us from clearing _last_native_pc down below.
2118     //
2119     save_native_result(masm, ret_type, stack_slots);
2120     __ mov(c_rarg0, rthread);
2121 #ifndef PRODUCT
2122   assert(frame::arg_reg_save_area_bytes == 0, "not expecting frame reg save area");
2123 #endif
2124     __ lea(rscratch1, RuntimeAddress(CAST_FROM_FN_PTR(address, JavaThread::check_special_condition_for_native_trans)));
2125     __ blr(rscratch1);
2126 
2127     // Restore any method result value
2128     restore_native_result(masm, ret_type, stack_slots);
2129 
2130     __ b(safepoint_in_progress_done);
2131     __ block_comment("} safepoint");
2132   }
2133 
2134   // SLOW PATH dtrace support
2135   if (DTraceMethodProbes) {
2136     {
2137       __ block_comment("dtrace entry {");
2138       __ bind(dtrace_method_entry);
2139 
2140       // We have all of the arguments setup at this point. We must not touch any register
2141       // argument registers at this point (what if we save/restore them there are no oop?
2142 
2143       save_args(masm, total_c_args, c_arg, out_regs);
2144       __ mov_metadata(c_rarg1, method());
2145       __ call_VM_leaf(
2146         CAST_FROM_FN_PTR(address, SharedRuntime::dtrace_method_entry),
2147         rthread, c_rarg1);
2148       restore_args(masm, total_c_args, c_arg, out_regs);
2149       __ b(dtrace_method_entry_done);
2150       __ block_comment("} dtrace entry");
2151     }
2152 
2153     {
2154       __ block_comment("dtrace exit {");
2155       __ bind(dtrace_method_exit);
2156       save_native_result(masm, ret_type, stack_slots);
2157       __ mov_metadata(c_rarg1, method());
2158       __ call_VM_leaf(
2159         CAST_FROM_FN_PTR(address, SharedRuntime::dtrace_method_exit),
2160         rthread, c_rarg1);
2161       restore_native_result(masm, ret_type, stack_slots);
2162       __ b(dtrace_method_exit_done);
2163       __ block_comment("} dtrace exit");
2164     }
2165   }
2166 
2167   __ flush();
2168 
2169   nmethod *nm = nmethod::new_native_nmethod(method,
2170                                             compile_id,
2171                                             masm->code(),
2172                                             vep_offset,
2173                                             frame_complete,
2174                                             stack_slots / VMRegImpl::slots_per_word,
2175                                             (is_static ? in_ByteSize(klass_offset) : in_ByteSize(receiver_offset)),
2176                                             in_ByteSize(lock_slot_offset*VMRegImpl::stack_slot_size),
2177                                             oop_maps);
2178 
2179   return nm;
2180 }
2181 
2182 // this function returns the adjust size (in number of words) to a c2i adapter
2183 // activation for use during deoptimization
2184 int Deoptimization::last_frame_adjust(int callee_parameters, int callee_locals) {
2185   assert(callee_locals >= callee_parameters,
2186           "test and remove; got more parms than locals");
2187   if (callee_locals < callee_parameters)
2188     return 0;                   // No adjustment for negative locals
2189   int diff = (callee_locals - callee_parameters) * Interpreter::stackElementWords;
2190   // diff is counted in stack words
2191   return align_up(diff, 2);
2192 }
2193 
2194 
2195 //------------------------------generate_deopt_blob----------------------------
2196 void SharedRuntime::generate_deopt_blob() {
2197   // Allocate space for the code
2198   ResourceMark rm;
2199   // Setup code generation tools
2200   int pad = 0;
2201 #if INCLUDE_JVMCI
2202   if (EnableJVMCI) {
2203     pad += 512; // Increase the buffer size when compiling for JVMCI
2204   }
2205 #endif
2206   CodeBuffer buffer("deopt_blob", 2048+pad, 1024);
2207   MacroAssembler* masm = new MacroAssembler(&buffer);
2208   int frame_size_in_words;
2209   OopMap* map = nullptr;
2210   OopMapSet *oop_maps = new OopMapSet();
2211   RegisterSaver reg_save(COMPILER2_OR_JVMCI != 0);
2212 
2213   // -------------
2214   // This code enters when returning to a de-optimized nmethod.  A return
2215   // address has been pushed on the stack, and return values are in
2216   // registers.
2217   // If we are doing a normal deopt then we were called from the patched
2218   // nmethod from the point we returned to the nmethod. So the return
2219   // address on the stack is wrong by NativeCall::instruction_size
2220   // We will adjust the value so it looks like we have the original return
2221   // address on the stack (like when we eagerly deoptimized).
2222   // In the case of an exception pending when deoptimizing, we enter
2223   // with a return address on the stack that points after the call we patched
2224   // into the exception handler. We have the following register state from,
2225   // e.g., the forward exception stub (see stubGenerator_x86_64.cpp).
2226   //    r0: exception oop
2227   //    r19: exception handler
2228   //    r3: throwing pc
2229   // So in this case we simply jam r3 into the useless return address and
2230   // the stack looks just like we want.
2231   //
2232   // At this point we need to de-opt.  We save the argument return
2233   // registers.  We call the first C routine, fetch_unroll_info().  This
2234   // routine captures the return values and returns a structure which
2235   // describes the current frame size and the sizes of all replacement frames.
2236   // The current frame is compiled code and may contain many inlined
2237   // functions, each with their own JVM state.  We pop the current frame, then
2238   // push all the new frames.  Then we call the C routine unpack_frames() to
2239   // populate these frames.  Finally unpack_frames() returns us the new target
2240   // address.  Notice that callee-save registers are BLOWN here; they have
2241   // already been captured in the vframeArray at the time the return PC was
2242   // patched.
2243   address start = __ pc();
2244   Label cont;
2245 
2246   // Prolog for non exception case!
2247 
2248   // Save everything in sight.
2249   map = reg_save.save_live_registers(masm, 0, &frame_size_in_words);
2250 
2251   // Normal deoptimization.  Save exec mode for unpack_frames.
2252   __ movw(rcpool, Deoptimization::Unpack_deopt); // callee-saved
2253   __ b(cont);
2254 
2255   int reexecute_offset = __ pc() - start;
2256 #if INCLUDE_JVMCI && !defined(COMPILER1)
2257   if (EnableJVMCI && UseJVMCICompiler) {
2258     // JVMCI does not use this kind of deoptimization
2259     __ should_not_reach_here();
2260   }
2261 #endif
2262 
2263   // Reexecute case
2264   // return address is the pc describes what bci to do re-execute at
2265 
2266   // No need to update map as each call to save_live_registers will produce identical oopmap
2267   (void) reg_save.save_live_registers(masm, 0, &frame_size_in_words);
2268 
2269   __ movw(rcpool, Deoptimization::Unpack_reexecute); // callee-saved
2270   __ b(cont);
2271 
2272 #if INCLUDE_JVMCI
2273   Label after_fetch_unroll_info_call;
2274   int implicit_exception_uncommon_trap_offset = 0;
2275   int uncommon_trap_offset = 0;
2276 
2277   if (EnableJVMCI) {
2278     implicit_exception_uncommon_trap_offset = __ pc() - start;
2279 
2280     __ ldr(lr, Address(rthread, in_bytes(JavaThread::jvmci_implicit_exception_pc_offset())));
2281     __ str(zr, Address(rthread, in_bytes(JavaThread::jvmci_implicit_exception_pc_offset())));
2282 
2283     uncommon_trap_offset = __ pc() - start;
2284 
2285     // Save everything in sight.
2286     reg_save.save_live_registers(masm, 0, &frame_size_in_words);
2287     // fetch_unroll_info needs to call last_java_frame()
2288     Label retaddr;
2289     __ set_last_Java_frame(sp, noreg, retaddr, rscratch1);
2290 
2291     __ ldrw(c_rarg1, Address(rthread, in_bytes(JavaThread::pending_deoptimization_offset())));
2292     __ movw(rscratch1, -1);
2293     __ strw(rscratch1, Address(rthread, in_bytes(JavaThread::pending_deoptimization_offset())));
2294 
2295     __ movw(rcpool, (int32_t)Deoptimization::Unpack_reexecute);
2296     __ mov(c_rarg0, rthread);
2297     __ movw(c_rarg2, rcpool); // exec mode
2298     __ lea(rscratch1,
2299            RuntimeAddress(CAST_FROM_FN_PTR(address,
2300                                            Deoptimization::uncommon_trap)));
2301     __ blr(rscratch1);
2302     __ bind(retaddr);
2303     oop_maps->add_gc_map( __ pc()-start, map->deep_copy());
2304 
2305     __ reset_last_Java_frame(false);
2306 
2307     __ b(after_fetch_unroll_info_call);
2308   } // EnableJVMCI
2309 #endif // INCLUDE_JVMCI
2310 
2311   int exception_offset = __ pc() - start;
2312 
2313   // Prolog for exception case
2314 
2315   // all registers are dead at this entry point, except for r0, and
2316   // r3 which contain the exception oop and exception pc
2317   // respectively.  Set them in TLS and fall thru to the
2318   // unpack_with_exception_in_tls entry point.
2319 
2320   __ str(r3, Address(rthread, JavaThread::exception_pc_offset()));
2321   __ str(r0, Address(rthread, JavaThread::exception_oop_offset()));
2322 
2323   int exception_in_tls_offset = __ pc() - start;
2324 
2325   // new implementation because exception oop is now passed in JavaThread
2326 
2327   // Prolog for exception case
2328   // All registers must be preserved because they might be used by LinearScan
2329   // Exceptiop oop and throwing PC are passed in JavaThread
2330   // tos: stack at point of call to method that threw the exception (i.e. only
2331   // args are on the stack, no return address)
2332 
2333   // The return address pushed by save_live_registers will be patched
2334   // later with the throwing pc. The correct value is not available
2335   // now because loading it from memory would destroy registers.
2336 
2337   // NB: The SP at this point must be the SP of the method that is
2338   // being deoptimized.  Deoptimization assumes that the frame created
2339   // here by save_live_registers is immediately below the method's SP.
2340   // This is a somewhat fragile mechanism.
2341 
2342   // Save everything in sight.
2343   map = reg_save.save_live_registers(masm, 0, &frame_size_in_words);
2344 
2345   // Now it is safe to overwrite any register
2346 
2347   // Deopt during an exception.  Save exec mode for unpack_frames.
2348   __ mov(rcpool, Deoptimization::Unpack_exception); // callee-saved
2349 
2350   // load throwing pc from JavaThread and patch it as the return address
2351   // of the current frame. Then clear the field in JavaThread
2352   __ ldr(r3, Address(rthread, JavaThread::exception_pc_offset()));
2353   __ protect_return_address(r3);
2354   __ str(r3, Address(rfp, wordSize));
2355   __ str(zr, Address(rthread, JavaThread::exception_pc_offset()));
2356 
2357 #ifdef ASSERT
2358   // verify that there is really an exception oop in JavaThread
2359   __ ldr(r0, Address(rthread, JavaThread::exception_oop_offset()));
2360   __ verify_oop(r0);
2361 
2362   // verify that there is no pending exception
2363   Label no_pending_exception;
2364   __ ldr(rscratch1, Address(rthread, Thread::pending_exception_offset()));
2365   __ cbz(rscratch1, no_pending_exception);
2366   __ stop("must not have pending exception here");
2367   __ bind(no_pending_exception);
2368 #endif
2369 
2370   __ bind(cont);
2371 
2372   // Call C code.  Need thread and this frame, but NOT official VM entry
2373   // crud.  We cannot block on this call, no GC can happen.
2374   //
2375   // UnrollBlock* fetch_unroll_info(JavaThread* thread)
2376 
2377   // fetch_unroll_info needs to call last_java_frame().
2378 
2379   Label retaddr;
2380   __ set_last_Java_frame(sp, noreg, retaddr, rscratch1);
2381 #ifdef ASSERT
2382   { Label L;
2383     __ ldr(rscratch1, Address(rthread, JavaThread::last_Java_fp_offset()));
2384     __ cbz(rscratch1, L);
2385     __ stop("SharedRuntime::generate_deopt_blob: last_Java_fp not cleared");
2386     __ bind(L);
2387   }
2388 #endif // ASSERT
2389   __ mov(c_rarg0, rthread);
2390   __ mov(c_rarg1, rcpool);
2391   __ lea(rscratch1, RuntimeAddress(CAST_FROM_FN_PTR(address, Deoptimization::fetch_unroll_info)));
2392   __ blr(rscratch1);
2393   __ bind(retaddr);
2394 
2395   // Need to have an oopmap that tells fetch_unroll_info where to
2396   // find any register it might need.
2397   oop_maps->add_gc_map(__ pc() - start, map);
2398 
2399   __ reset_last_Java_frame(false);
2400 
2401 #if INCLUDE_JVMCI
2402   if (EnableJVMCI) {
2403     __ bind(after_fetch_unroll_info_call);
2404   }
2405 #endif
2406 
2407   // Load UnrollBlock* into r5
2408   __ mov(r5, r0);
2409 
2410   __ ldrw(rcpool, Address(r5, Deoptimization::UnrollBlock::unpack_kind_offset()));
2411    Label noException;
2412   __ cmpw(rcpool, Deoptimization::Unpack_exception);   // Was exception pending?
2413   __ br(Assembler::NE, noException);
2414   __ ldr(r0, Address(rthread, JavaThread::exception_oop_offset()));
2415   // QQQ this is useless it was null above
2416   __ ldr(r3, Address(rthread, JavaThread::exception_pc_offset()));
2417   __ str(zr, Address(rthread, JavaThread::exception_oop_offset()));
2418   __ str(zr, Address(rthread, JavaThread::exception_pc_offset()));
2419 
2420   __ verify_oop(r0);
2421 
2422   // Overwrite the result registers with the exception results.
2423   __ str(r0, Address(sp, reg_save.r0_offset_in_bytes()));
2424   // I think this is useless
2425   // __ str(r3, Address(sp, RegisterSaver::r3_offset_in_bytes()));
2426 
2427   __ bind(noException);
2428 
2429   // Only register save data is on the stack.
2430   // Now restore the result registers.  Everything else is either dead
2431   // or captured in the vframeArray.
2432 
2433   // Restore fp result register
2434   __ ldrd(v0, Address(sp, reg_save.v0_offset_in_bytes()));
2435   // Restore integer result register
2436   __ ldr(r0, Address(sp, reg_save.r0_offset_in_bytes()));
2437 
2438   // Pop all of the register save area off the stack
2439   __ add(sp, sp, frame_size_in_words * wordSize);
2440 
2441   // All of the register save area has been popped of the stack. Only the
2442   // return address remains.
2443 
2444   // Pop all the frames we must move/replace.
2445   //
2446   // Frame picture (youngest to oldest)
2447   // 1: self-frame (no frame link)
2448   // 2: deopting frame  (no frame link)
2449   // 3: caller of deopting frame (could be compiled/interpreted).
2450   //
2451   // Note: by leaving the return address of self-frame on the stack
2452   // and using the size of frame 2 to adjust the stack
2453   // when we are done the return to frame 3 will still be on the stack.
2454 
2455   // Pop deoptimized frame
2456   __ ldrw(r2, Address(r5, Deoptimization::UnrollBlock::size_of_deoptimized_frame_offset()));
2457   __ sub(r2, r2, 2 * wordSize);
2458   __ add(sp, sp, r2);
2459   __ ldp(rfp, zr, __ post(sp, 2 * wordSize));
2460 
2461 #ifdef ASSERT
2462   // Compilers generate code that bang the stack by as much as the
2463   // interpreter would need. So this stack banging should never
2464   // trigger a fault. Verify that it does not on non product builds.
2465   __ ldrw(r19, Address(r5, Deoptimization::UnrollBlock::total_frame_sizes_offset()));
2466   __ bang_stack_size(r19, r2);
2467 #endif
2468   // Load address of array of frame pcs into r2
2469   __ ldr(r2, Address(r5, Deoptimization::UnrollBlock::frame_pcs_offset()));
2470 
2471   // Trash the old pc
2472   // __ addptr(sp, wordSize);  FIXME ????
2473 
2474   // Load address of array of frame sizes into r4
2475   __ ldr(r4, Address(r5, Deoptimization::UnrollBlock::frame_sizes_offset()));
2476 
2477   // Load counter into r3
2478   __ ldrw(r3, Address(r5, Deoptimization::UnrollBlock::number_of_frames_offset()));
2479 
2480   // Now adjust the caller's stack to make up for the extra locals
2481   // but record the original sp so that we can save it in the skeletal interpreter
2482   // frame and the stack walking of interpreter_sender will get the unextended sp
2483   // value and not the "real" sp value.
2484 
2485   const Register sender_sp = r6;
2486 
2487   __ mov(sender_sp, sp);
2488   __ ldrw(r19, Address(r5,
2489                        Deoptimization::UnrollBlock::
2490                        caller_adjustment_offset()));
2491   __ sub(sp, sp, r19);
2492 
2493   // Push interpreter frames in a loop
2494   __ mov(rscratch1, (uint64_t)0xDEADDEAD);        // Make a recognizable pattern
2495   __ mov(rscratch2, rscratch1);
2496   Label loop;
2497   __ bind(loop);
2498   __ ldr(r19, Address(__ post(r4, wordSize)));          // Load frame size
2499   __ sub(r19, r19, 2*wordSize);           // We'll push pc and fp by hand
2500   __ ldr(lr, Address(__ post(r2, wordSize)));  // Load pc
2501   __ enter();                           // Save old & set new fp
2502   __ sub(sp, sp, r19);                  // Prolog
2503   // This value is corrected by layout_activation_impl
2504   __ str(zr, Address(rfp, frame::interpreter_frame_last_sp_offset * wordSize));
2505   __ str(sender_sp, Address(rfp, frame::interpreter_frame_sender_sp_offset * wordSize)); // Make it walkable
2506   __ mov(sender_sp, sp);               // Pass sender_sp to next frame
2507   __ sub(r3, r3, 1);                   // Decrement counter
2508   __ cbnz(r3, loop);
2509 
2510     // Re-push self-frame
2511   __ ldr(lr, Address(r2));
2512   __ enter();
2513 
2514   // Allocate a full sized register save area.  We subtract 2 because
2515   // enter() just pushed 2 words
2516   __ sub(sp, sp, (frame_size_in_words - 2) * wordSize);
2517 
2518   // Restore frame locals after moving the frame
2519   __ strd(v0, Address(sp, reg_save.v0_offset_in_bytes()));
2520   __ str(r0, Address(sp, reg_save.r0_offset_in_bytes()));
2521 
2522   // Call C code.  Need thread but NOT official VM entry
2523   // crud.  We cannot block on this call, no GC can happen.  Call should
2524   // restore return values to their stack-slots with the new SP.
2525   //
2526   // void Deoptimization::unpack_frames(JavaThread* thread, int exec_mode)
2527 
2528   // Use rfp because the frames look interpreted now
2529   // Don't need the precise return PC here, just precise enough to point into this code blob.
2530   address the_pc = __ pc();
2531   __ set_last_Java_frame(sp, rfp, the_pc, rscratch1);
2532 
2533   __ mov(c_rarg0, rthread);
2534   __ movw(c_rarg1, rcpool); // second arg: exec_mode
2535   __ lea(rscratch1, RuntimeAddress(CAST_FROM_FN_PTR(address, Deoptimization::unpack_frames)));
2536   __ blr(rscratch1);
2537 
2538   // Set an oopmap for the call site
2539   // Use the same PC we used for the last java frame
2540   oop_maps->add_gc_map(the_pc - start,
2541                        new OopMap( frame_size_in_words, 0 ));
2542 
2543   // Clear fp AND pc
2544   __ reset_last_Java_frame(true);
2545 
2546   // Collect return values
2547   __ ldrd(v0, Address(sp, reg_save.v0_offset_in_bytes()));
2548   __ ldr(r0, Address(sp, reg_save.r0_offset_in_bytes()));
2549   // I think this is useless (throwing pc?)
2550   // __ ldr(r3, Address(sp, RegisterSaver::r3_offset_in_bytes()));
2551 
2552   // Pop self-frame.
2553   __ leave();                           // Epilog
2554 
2555   // Jump to interpreter
2556   __ ret(lr);
2557 
2558   // Make sure all code is generated
2559   masm->flush();
2560 
2561   _deopt_blob = DeoptimizationBlob::create(&buffer, oop_maps, 0, exception_offset, reexecute_offset, frame_size_in_words);
2562   _deopt_blob->set_unpack_with_exception_in_tls_offset(exception_in_tls_offset);
2563 #if INCLUDE_JVMCI
2564   if (EnableJVMCI) {
2565     _deopt_blob->set_uncommon_trap_offset(uncommon_trap_offset);
2566     _deopt_blob->set_implicit_exception_uncommon_trap_offset(implicit_exception_uncommon_trap_offset);
2567   }
2568 #endif
2569 }
2570 
2571 // Number of stack slots between incoming argument block and the start of
2572 // a new frame.  The PROLOG must add this many slots to the stack.  The
2573 // EPILOG must remove this many slots. aarch64 needs two slots for
2574 // return address and fp.
2575 // TODO think this is correct but check
2576 uint SharedRuntime::in_preserve_stack_slots() {
2577   return 4;
2578 }
2579 
2580 uint SharedRuntime::out_preserve_stack_slots() {
2581   return 0;
2582 }
2583 
2584 #ifdef COMPILER2
2585 //------------------------------generate_uncommon_trap_blob--------------------
2586 void SharedRuntime::generate_uncommon_trap_blob() {
2587   // Allocate space for the code
2588   ResourceMark rm;
2589   // Setup code generation tools
2590   CodeBuffer buffer("uncommon_trap_blob", 2048, 1024);
2591   MacroAssembler* masm = new MacroAssembler(&buffer);
2592 
2593   assert(SimpleRuntimeFrame::framesize % 4 == 0, "sp not 16-byte aligned");
2594 
2595   address start = __ pc();
2596 
2597   // Push self-frame.  We get here with a return address in LR
2598   // and sp should be 16 byte aligned
2599   // push rfp and retaddr by hand
2600   __ protect_return_address();
2601   __ stp(rfp, lr, Address(__ pre(sp, -2 * wordSize)));
2602   // we don't expect an arg reg save area
2603 #ifndef PRODUCT
2604   assert(frame::arg_reg_save_area_bytes == 0, "not expecting frame reg save area");
2605 #endif
2606   // compiler left unloaded_class_index in j_rarg0 move to where the
2607   // runtime expects it.
2608   if (c_rarg1 != j_rarg0) {
2609     __ movw(c_rarg1, j_rarg0);
2610   }
2611 
2612   // we need to set the past SP to the stack pointer of the stub frame
2613   // and the pc to the address where this runtime call will return
2614   // although actually any pc in this code blob will do).
2615   Label retaddr;
2616   __ set_last_Java_frame(sp, noreg, retaddr, rscratch1);
2617 
2618   // Call C code.  Need thread but NOT official VM entry
2619   // crud.  We cannot block on this call, no GC can happen.  Call should
2620   // capture callee-saved registers as well as return values.
2621   // Thread is in rdi already.
2622   //
2623   // UnrollBlock* uncommon_trap(JavaThread* thread, jint unloaded_class_index);
2624   //
2625   // n.b. 2 gp args, 0 fp args, integral return type
2626 
2627   __ mov(c_rarg0, rthread);
2628   __ movw(c_rarg2, (unsigned)Deoptimization::Unpack_uncommon_trap);
2629   __ lea(rscratch1,
2630          RuntimeAddress(CAST_FROM_FN_PTR(address,
2631                                          Deoptimization::uncommon_trap)));
2632   __ blr(rscratch1);
2633   __ bind(retaddr);
2634 
2635   // Set an oopmap for the call site
2636   OopMapSet* oop_maps = new OopMapSet();
2637   OopMap* map = new OopMap(SimpleRuntimeFrame::framesize, 0);
2638 
2639   // location of rfp is known implicitly by the frame sender code
2640 
2641   oop_maps->add_gc_map(__ pc() - start, map);
2642 
2643   __ reset_last_Java_frame(false);
2644 
2645   // move UnrollBlock* into r4
2646   __ mov(r4, r0);
2647 
2648 #ifdef ASSERT
2649   { Label L;
2650     __ ldrw(rscratch1, Address(r4, Deoptimization::UnrollBlock::unpack_kind_offset()));
2651     __ cmpw(rscratch1, (unsigned)Deoptimization::Unpack_uncommon_trap);
2652     __ br(Assembler::EQ, L);
2653     __ stop("SharedRuntime::generate_uncommon_trap_blob: expected Unpack_uncommon_trap");
2654     __ bind(L);
2655   }
2656 #endif
2657 
2658   // Pop all the frames we must move/replace.
2659   //
2660   // Frame picture (youngest to oldest)
2661   // 1: self-frame (no frame link)
2662   // 2: deopting frame  (no frame link)
2663   // 3: caller of deopting frame (could be compiled/interpreted).
2664 
2665   // Pop self-frame.  We have no frame, and must rely only on r0 and sp.
2666   __ add(sp, sp, (SimpleRuntimeFrame::framesize) << LogBytesPerInt); // Epilog!
2667 
2668   // Pop deoptimized frame (int)
2669   __ ldrw(r2, Address(r4,
2670                       Deoptimization::UnrollBlock::
2671                       size_of_deoptimized_frame_offset()));
2672   __ sub(r2, r2, 2 * wordSize);
2673   __ add(sp, sp, r2);
2674   __ ldp(rfp, zr, __ post(sp, 2 * wordSize));
2675 
2676 #ifdef ASSERT
2677   // Compilers generate code that bang the stack by as much as the
2678   // interpreter would need. So this stack banging should never
2679   // trigger a fault. Verify that it does not on non product builds.
2680   __ ldrw(r1, Address(r4,
2681                       Deoptimization::UnrollBlock::
2682                       total_frame_sizes_offset()));
2683   __ bang_stack_size(r1, r2);
2684 #endif
2685 
2686   // Load address of array of frame pcs into r2 (address*)
2687   __ ldr(r2, Address(r4,
2688                      Deoptimization::UnrollBlock::frame_pcs_offset()));
2689 
2690   // Load address of array of frame sizes into r5 (intptr_t*)
2691   __ ldr(r5, Address(r4,
2692                      Deoptimization::UnrollBlock::
2693                      frame_sizes_offset()));
2694 
2695   // Counter
2696   __ ldrw(r3, Address(r4,
2697                       Deoptimization::UnrollBlock::
2698                       number_of_frames_offset())); // (int)
2699 
2700   // Now adjust the caller's stack to make up for the extra locals but
2701   // record the original sp so that we can save it in the skeletal
2702   // interpreter frame and the stack walking of interpreter_sender
2703   // will get the unextended sp value and not the "real" sp value.
2704 
2705   const Register sender_sp = r8;
2706 
2707   __ mov(sender_sp, sp);
2708   __ ldrw(r1, Address(r4,
2709                       Deoptimization::UnrollBlock::
2710                       caller_adjustment_offset())); // (int)
2711   __ sub(sp, sp, r1);
2712 
2713   // Push interpreter frames in a loop
2714   Label loop;
2715   __ bind(loop);
2716   __ ldr(r1, Address(r5, 0));       // Load frame size
2717   __ sub(r1, r1, 2 * wordSize);     // We'll push pc and rfp by hand
2718   __ ldr(lr, Address(r2, 0));       // Save return address
2719   __ enter();                       // and old rfp & set new rfp
2720   __ sub(sp, sp, r1);               // Prolog
2721   __ str(sender_sp, Address(rfp, frame::interpreter_frame_sender_sp_offset * wordSize)); // Make it walkable
2722   // This value is corrected by layout_activation_impl
2723   __ str(zr, Address(rfp, frame::interpreter_frame_last_sp_offset * wordSize));
2724   __ mov(sender_sp, sp);          // Pass sender_sp to next frame
2725   __ add(r5, r5, wordSize);       // Bump array pointer (sizes)
2726   __ add(r2, r2, wordSize);       // Bump array pointer (pcs)
2727   __ subsw(r3, r3, 1);            // Decrement counter
2728   __ br(Assembler::GT, loop);
2729   __ ldr(lr, Address(r2, 0));     // save final return address
2730   // Re-push self-frame
2731   __ enter();                     // & old rfp & set new rfp
2732 
2733   // Use rfp because the frames look interpreted now
2734   // Save "the_pc" since it cannot easily be retrieved using the last_java_SP after we aligned SP.
2735   // Don't need the precise return PC here, just precise enough to point into this code blob.
2736   address the_pc = __ pc();
2737   __ set_last_Java_frame(sp, rfp, the_pc, rscratch1);
2738 
2739   // Call C code.  Need thread but NOT official VM entry
2740   // crud.  We cannot block on this call, no GC can happen.  Call should
2741   // restore return values to their stack-slots with the new SP.
2742   // Thread is in rdi already.
2743   //
2744   // BasicType unpack_frames(JavaThread* thread, int exec_mode);
2745   //
2746   // n.b. 2 gp args, 0 fp args, integral return type
2747 
2748   // sp should already be aligned
2749   __ mov(c_rarg0, rthread);
2750   __ movw(c_rarg1, (unsigned)Deoptimization::Unpack_uncommon_trap);
2751   __ lea(rscratch1, RuntimeAddress(CAST_FROM_FN_PTR(address, Deoptimization::unpack_frames)));
2752   __ blr(rscratch1);
2753 
2754   // Set an oopmap for the call site
2755   // Use the same PC we used for the last java frame
2756   oop_maps->add_gc_map(the_pc - start, new OopMap(SimpleRuntimeFrame::framesize, 0));
2757 
2758   // Clear fp AND pc
2759   __ reset_last_Java_frame(true);
2760 
2761   // Pop self-frame.
2762   __ leave();                 // Epilog
2763 
2764   // Jump to interpreter
2765   __ ret(lr);
2766 
2767   // Make sure all code is generated
2768   masm->flush();
2769 
2770   _uncommon_trap_blob =  UncommonTrapBlob::create(&buffer, oop_maps,
2771                                                  SimpleRuntimeFrame::framesize >> 1);
2772 }
2773 #endif // COMPILER2
2774 
2775 
2776 //------------------------------generate_handler_blob------
2777 //
2778 // Generate a special Compile2Runtime blob that saves all registers,
2779 // and setup oopmap.
2780 //
2781 SafepointBlob* SharedRuntime::generate_handler_blob(address call_ptr, int poll_type) {
2782   ResourceMark rm;
2783   OopMapSet *oop_maps = new OopMapSet();
2784   OopMap* map;
2785 
2786   // Allocate space for the code.  Setup code generation tools.
2787   CodeBuffer buffer("handler_blob", 2048, 1024);
2788   MacroAssembler* masm = new MacroAssembler(&buffer);
2789 
2790   address start   = __ pc();
2791   address call_pc = nullptr;
2792   int frame_size_in_words;
2793   bool cause_return = (poll_type == POLL_AT_RETURN);
2794   RegisterSaver reg_save(poll_type == POLL_AT_VECTOR_LOOP /* save_vectors */);
2795 
2796   // When the signal occurred, the LR was either signed and stored on the stack (in which
2797   // case it will be restored from the stack before being used) or unsigned and not stored
2798   // on the stack. Stipping ensures we get the right value.
2799   __ strip_return_address();
2800 
2801   // Save Integer and Float registers.
2802   map = reg_save.save_live_registers(masm, 0, &frame_size_in_words);
2803 
2804   // The following is basically a call_VM.  However, we need the precise
2805   // address of the call in order to generate an oopmap. Hence, we do all the
2806   // work ourselves.
2807 
2808   Label retaddr;
2809   __ set_last_Java_frame(sp, noreg, retaddr, rscratch1);
2810 
2811   // The return address must always be correct so that frame constructor never
2812   // sees an invalid pc.
2813 
2814   if (!cause_return) {
2815     // overwrite the return address pushed by save_live_registers
2816     // Additionally, r20 is a callee-saved register so we can look at
2817     // it later to determine if someone changed the return address for
2818     // us!
2819     __ ldr(r20, Address(rthread, JavaThread::saved_exception_pc_offset()));
2820     __ protect_return_address(r20);
2821     __ str(r20, Address(rfp, wordSize));
2822   }
2823 
2824   // Do the call
2825   __ mov(c_rarg0, rthread);
2826   __ lea(rscratch1, RuntimeAddress(call_ptr));
2827   __ blr(rscratch1);
2828   __ bind(retaddr);
2829 
2830   // Set an oopmap for the call site.  This oopmap will map all
2831   // oop-registers and debug-info registers as callee-saved.  This
2832   // will allow deoptimization at this safepoint to find all possible
2833   // debug-info recordings, as well as let GC find all oops.
2834 
2835   oop_maps->add_gc_map( __ pc() - start, map);
2836 
2837   Label noException;
2838 
2839   __ reset_last_Java_frame(false);
2840 
2841   __ membar(Assembler::LoadLoad | Assembler::LoadStore);
2842 
2843   __ ldr(rscratch1, Address(rthread, Thread::pending_exception_offset()));
2844   __ cbz(rscratch1, noException);
2845 
2846   // Exception pending
2847 
2848   reg_save.restore_live_registers(masm);
2849 
2850   __ far_jump(RuntimeAddress(StubRoutines::forward_exception_entry()));
2851 
2852   // No exception case
2853   __ bind(noException);
2854 
2855   Label no_adjust, bail;
2856   if (!cause_return) {
2857     // If our stashed return pc was modified by the runtime we avoid touching it
2858     __ ldr(rscratch1, Address(rfp, wordSize));
2859     __ cmp(r20, rscratch1);
2860     __ br(Assembler::NE, no_adjust);
2861     __ authenticate_return_address(r20);
2862 
2863 #ifdef ASSERT
2864     // Verify the correct encoding of the poll we're about to skip.
2865     // See NativeInstruction::is_ldrw_to_zr()
2866     __ ldrw(rscratch1, Address(r20));
2867     __ ubfx(rscratch2, rscratch1, 22, 10);
2868     __ cmpw(rscratch2, 0b1011100101);
2869     __ br(Assembler::NE, bail);
2870     __ ubfx(rscratch2, rscratch1, 0, 5);
2871     __ cmpw(rscratch2, 0b11111);
2872     __ br(Assembler::NE, bail);
2873 #endif
2874     // Adjust return pc forward to step over the safepoint poll instruction
2875     __ add(r20, r20, NativeInstruction::instruction_size);
2876     __ protect_return_address(r20);
2877     __ str(r20, Address(rfp, wordSize));
2878   }
2879 
2880   __ bind(no_adjust);
2881   // Normal exit, restore registers and exit.
2882   reg_save.restore_live_registers(masm);
2883 
2884   __ ret(lr);
2885 
2886 #ifdef ASSERT
2887   __ bind(bail);
2888   __ stop("Attempting to adjust pc to skip safepoint poll but the return point is not what we expected");
2889 #endif
2890 
2891   // Make sure all code is generated
2892   masm->flush();
2893 
2894   // Fill-out other meta info
2895   return SafepointBlob::create(&buffer, oop_maps, frame_size_in_words);
2896 }
2897 
2898 //
2899 // generate_resolve_blob - call resolution (static/virtual/opt-virtual/ic-miss
2900 //
2901 // Generate a stub that calls into vm to find out the proper destination
2902 // of a java call. All the argument registers are live at this point
2903 // but since this is generic code we don't know what they are and the caller
2904 // must do any gc of the args.
2905 //
2906 RuntimeStub* SharedRuntime::generate_resolve_blob(address destination, const char* name) {
2907   assert (StubRoutines::forward_exception_entry() != nullptr, "must be generated before");
2908 
2909   // allocate space for the code
2910   ResourceMark rm;
2911 
2912   CodeBuffer buffer(name, 1000, 512);
2913   MacroAssembler* masm                = new MacroAssembler(&buffer);
2914 
2915   int frame_size_in_words;
2916   RegisterSaver reg_save(false /* save_vectors */);
2917 
2918   OopMapSet *oop_maps = new OopMapSet();
2919   OopMap* map = nullptr;
2920 
2921   int start = __ offset();
2922 
2923   map = reg_save.save_live_registers(masm, 0, &frame_size_in_words);
2924 
2925   int frame_complete = __ offset();
2926 
2927   {
2928     Label retaddr;
2929     __ set_last_Java_frame(sp, noreg, retaddr, rscratch1);
2930 
2931     __ mov(c_rarg0, rthread);
2932     __ lea(rscratch1, RuntimeAddress(destination));
2933 
2934     __ blr(rscratch1);
2935     __ bind(retaddr);
2936   }
2937 
2938   // Set an oopmap for the call site.
2939   // We need this not only for callee-saved registers, but also for volatile
2940   // registers that the compiler might be keeping live across a safepoint.
2941 
2942   oop_maps->add_gc_map( __ offset() - start, map);
2943 
2944   // r0 contains the address we are going to jump to assuming no exception got installed
2945 
2946   // clear last_Java_sp
2947   __ reset_last_Java_frame(false);
2948   // check for pending exceptions
2949   Label pending;
2950   __ ldr(rscratch1, Address(rthread, Thread::pending_exception_offset()));
2951   __ cbnz(rscratch1, pending);
2952 
2953   // get the returned Method*
2954   __ get_vm_result_2(rmethod, rthread);
2955   __ str(rmethod, Address(sp, reg_save.reg_offset_in_bytes(rmethod)));
2956 
2957   // r0 is where we want to jump, overwrite rscratch1 which is saved and scratch
2958   __ str(r0, Address(sp, reg_save.rscratch1_offset_in_bytes()));
2959   reg_save.restore_live_registers(masm);
2960 
2961   // We are back to the original state on entry and ready to go.
2962 
2963   __ br(rscratch1);
2964 
2965   // Pending exception after the safepoint
2966 
2967   __ bind(pending);
2968 
2969   reg_save.restore_live_registers(masm);
2970 
2971   // exception pending => remove activation and forward to exception handler
2972 
2973   __ str(zr, Address(rthread, JavaThread::vm_result_offset()));
2974 
2975   __ ldr(r0, Address(rthread, Thread::pending_exception_offset()));
2976   __ far_jump(RuntimeAddress(StubRoutines::forward_exception_entry()));
2977 
2978   // -------------
2979   // make sure all code is generated
2980   masm->flush();
2981 
2982   // return the  blob
2983   // frame_size_words or bytes??
2984   return RuntimeStub::new_runtime_stub(name, &buffer, frame_complete, frame_size_in_words, oop_maps, true);
2985 }
2986 
2987 #ifdef COMPILER2
2988 // This is here instead of runtime_aarch64_64.cpp because it uses SimpleRuntimeFrame
2989 //
2990 //------------------------------generate_exception_blob---------------------------
2991 // creates exception blob at the end
2992 // Using exception blob, this code is jumped from a compiled method.
2993 // (see emit_exception_handler in x86_64.ad file)
2994 //
2995 // Given an exception pc at a call we call into the runtime for the
2996 // handler in this method. This handler might merely restore state
2997 // (i.e. callee save registers) unwind the frame and jump to the
2998 // exception handler for the nmethod if there is no Java level handler
2999 // for the nmethod.
3000 //
3001 // This code is entered with a jmp.
3002 //
3003 // Arguments:
3004 //   r0: exception oop
3005 //   r3: exception pc
3006 //
3007 // Results:
3008 //   r0: exception oop
3009 //   r3: exception pc in caller or ???
3010 //   destination: exception handler of caller
3011 //
3012 // Note: the exception pc MUST be at a call (precise debug information)
3013 //       Registers r0, r3, r2, r4, r5, r8-r11 are not callee saved.
3014 //
3015 
3016 void OptoRuntime::generate_exception_blob() {
3017   assert(!OptoRuntime::is_callee_saved_register(R3_num), "");
3018   assert(!OptoRuntime::is_callee_saved_register(R0_num), "");
3019   assert(!OptoRuntime::is_callee_saved_register(R2_num), "");
3020 
3021   assert(SimpleRuntimeFrame::framesize % 4 == 0, "sp not 16-byte aligned");
3022 
3023   // Allocate space for the code
3024   ResourceMark rm;
3025   // Setup code generation tools
3026   CodeBuffer buffer("exception_blob", 2048, 1024);
3027   MacroAssembler* masm = new MacroAssembler(&buffer);
3028 
3029   // TODO check various assumptions made here
3030   //
3031   // make sure we do so before running this
3032 
3033   address start = __ pc();
3034 
3035   // push rfp and retaddr by hand
3036   // Exception pc is 'return address' for stack walker
3037   __ protect_return_address();
3038   __ stp(rfp, lr, Address(__ pre(sp, -2 * wordSize)));
3039   // there are no callee save registers and we don't expect an
3040   // arg reg save area
3041 #ifndef PRODUCT
3042   assert(frame::arg_reg_save_area_bytes == 0, "not expecting frame reg save area");
3043 #endif
3044   // Store exception in Thread object. We cannot pass any arguments to the
3045   // handle_exception call, since we do not want to make any assumption
3046   // about the size of the frame where the exception happened in.
3047   __ str(r0, Address(rthread, JavaThread::exception_oop_offset()));
3048   __ str(r3, Address(rthread, JavaThread::exception_pc_offset()));
3049 
3050   // This call does all the hard work.  It checks if an exception handler
3051   // exists in the method.
3052   // If so, it returns the handler address.
3053   // If not, it prepares for stack-unwinding, restoring the callee-save
3054   // registers of the frame being removed.
3055   //
3056   // address OptoRuntime::handle_exception_C(JavaThread* thread)
3057   //
3058   // n.b. 1 gp arg, 0 fp args, integral return type
3059 
3060   // the stack should always be aligned
3061   address the_pc = __ pc();
3062   __ set_last_Java_frame(sp, noreg, the_pc, rscratch1);
3063   __ mov(c_rarg0, rthread);
3064   __ lea(rscratch1, RuntimeAddress(CAST_FROM_FN_PTR(address, OptoRuntime::handle_exception_C)));
3065   __ blr(rscratch1);
3066   // handle_exception_C is a special VM call which does not require an explicit
3067   // instruction sync afterwards.
3068 
3069   // May jump to SVE compiled code
3070   __ reinitialize_ptrue();
3071 
3072   // Set an oopmap for the call site.  This oopmap will only be used if we
3073   // are unwinding the stack.  Hence, all locations will be dead.
3074   // Callee-saved registers will be the same as the frame above (i.e.,
3075   // handle_exception_stub), since they were restored when we got the
3076   // exception.
3077 
3078   OopMapSet* oop_maps = new OopMapSet();
3079 
3080   oop_maps->add_gc_map(the_pc - start, new OopMap(SimpleRuntimeFrame::framesize, 0));
3081 
3082   __ reset_last_Java_frame(false);
3083 
3084   // Restore callee-saved registers
3085 
3086   // rfp is an implicitly saved callee saved register (i.e. the calling
3087   // convention will save restore it in prolog/epilog) Other than that
3088   // there are no callee save registers now that adapter frames are gone.
3089   // and we dont' expect an arg reg save area
3090   __ ldp(rfp, r3, Address(__ post(sp, 2 * wordSize)));
3091   __ authenticate_return_address(r3);
3092 
3093   // r0: exception handler
3094 
3095   // We have a handler in r0 (could be deopt blob).
3096   __ mov(r8, r0);
3097 
3098   // Get the exception oop
3099   __ ldr(r0, Address(rthread, JavaThread::exception_oop_offset()));
3100   // Get the exception pc in case we are deoptimized
3101   __ ldr(r4, Address(rthread, JavaThread::exception_pc_offset()));
3102 #ifdef ASSERT
3103   __ str(zr, Address(rthread, JavaThread::exception_handler_pc_offset()));
3104   __ str(zr, Address(rthread, JavaThread::exception_pc_offset()));
3105 #endif
3106   // Clear the exception oop so GC no longer processes it as a root.
3107   __ str(zr, Address(rthread, JavaThread::exception_oop_offset()));
3108 
3109   // r0: exception oop
3110   // r8:  exception handler
3111   // r4: exception pc
3112   // Jump to handler
3113 
3114   __ br(r8);
3115 
3116   // Make sure all code is generated
3117   masm->flush();
3118 
3119   // Set exception blob
3120   _exception_blob =  ExceptionBlob::create(&buffer, oop_maps, SimpleRuntimeFrame::framesize >> 1);
3121 }
3122 
3123 #endif // COMPILER2