1 /*
   2  * Copyright (c) 2003, 2026, Oracle and/or its affiliates. All rights reserved.
   3  * Copyright (c) 2014, 2020, Red Hat Inc. All rights reserved.
   4  * Copyright (c) 2020, 2023, Huawei Technologies Co., Ltd. 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 "asm/macroAssembler.hpp"
  28 #include "asm/macroAssembler.inline.hpp"
  29 #include "code/compiledIC.hpp"
  30 #include "code/debugInfoRec.hpp"
  31 #include "code/vtableStubs.hpp"
  32 #include "compiler/oopMap.hpp"
  33 #include "gc/shared/barrierSetAssembler.hpp"
  34 #include "interpreter/interp_masm.hpp"
  35 #include "interpreter/interpreter.hpp"
  36 #include "logging/log.hpp"
  37 #include "memory/resourceArea.hpp"
  38 #include "nativeInst_riscv.hpp"
  39 #include "oops/klass.inline.hpp"
  40 #include "oops/method.inline.hpp"
  41 #include "prims/methodHandles.hpp"
  42 #include "runtime/continuation.hpp"
  43 #include "runtime/continuationEntry.inline.hpp"
  44 #include "runtime/globals.hpp"
  45 #include "runtime/jniHandles.hpp"
  46 #include "runtime/safepointMechanism.hpp"
  47 #include "runtime/sharedRuntime.hpp"
  48 #include "runtime/signature.hpp"
  49 #include "runtime/stubRoutines.hpp"
  50 #include "runtime/timerTrace.hpp"
  51 #include "runtime/vframeArray.hpp"
  52 #include "utilities/align.hpp"
  53 #include "utilities/formatBuffer.hpp"
  54 #include "vmreg_riscv.inline.hpp"
  55 #ifdef COMPILER1
  56 #include "c1/c1_Runtime1.hpp"
  57 #endif
  58 #ifdef COMPILER2
  59 #include "adfiles/ad_riscv.hpp"
  60 #include "opto/runtime.hpp"
  61 #endif
  62 #if INCLUDE_SHENANDOAHGC
  63 #include "gc/shenandoah/shenandoahRuntime.hpp"
  64 #endif
  65 #if INCLUDE_JVMCI
  66 #include "jvmci/jvmciJavaClasses.hpp"
  67 #endif
  68 
  69 #define __ masm->
  70 
  71 #ifdef PRODUCT
  72 #define BLOCK_COMMENT(str) /* nothing */
  73 #else
  74 #define BLOCK_COMMENT(str) __ block_comment(str)
  75 #endif
  76 
  77 const int StackAlignmentInSlots = StackAlignmentInBytes / VMRegImpl::stack_slot_size;
  78 
  79 class RegisterSaver {
  80   const bool _save_vectors;
  81  public:
  82   RegisterSaver(bool save_vectors) : _save_vectors(UseRVV && save_vectors) {}
  83   ~RegisterSaver() {}
  84   OopMap* save_live_registers(MacroAssembler* masm, int additional_frame_words, int* total_frame_words);
  85   void restore_live_registers(MacroAssembler* masm);
  86 
  87   // Offsets into the register save area
  88   // Used by deoptimization when it is managing result register
  89   // values on its own
  90   // gregs:28, float_register:32; except: x1(ra) & x2(sp) & gp(x3) & tp(x4)
  91   // |---v0---|<---SP
  92   // |---v1---|save vectors only in generate_handler_blob
  93   // |-- .. --|
  94   // |---v31--|-----
  95   // |---f0---|
  96   // |---f1---|
  97   // |   ..   |
  98   // |---f31--|
  99   // |---reserved slot for stack alignment---|
 100   // |---x5---|
 101   // |   x6   |
 102   // |---.. --|
 103   // |---x31--|
 104   // |---fp---|
 105   // |---ra---|
 106   int v0_offset_in_bytes(void) { return 0; }
 107   int f0_offset_in_bytes(void) {
 108     int f0_offset = 0;
 109 #ifdef COMPILER2
 110     if (_save_vectors) {
 111       f0_offset += Matcher::scalable_vector_reg_size(T_INT) * VectorRegister::number_of_registers *
 112                    BytesPerInt;
 113     }
 114 #endif
 115     return f0_offset;
 116   }
 117   int reserved_slot_offset_in_bytes(void) {
 118     return f0_offset_in_bytes() +
 119            FloatRegister::max_slots_per_register *
 120            FloatRegister::number_of_registers *
 121            BytesPerInt;
 122   }
 123 
 124   int reg_offset_in_bytes(Register r) {
 125     assert (r->encoding() > 4, "ra, sp, gp and tp not saved");
 126     return reserved_slot_offset_in_bytes() + (r->encoding() - 4 /* x1, x2, x3, x4 */) * wordSize;
 127   }
 128 
 129   int freg_offset_in_bytes(FloatRegister f) {
 130     return f0_offset_in_bytes() + f->encoding() * wordSize;
 131   }
 132 
 133   int ra_offset_in_bytes(void) {
 134     return reserved_slot_offset_in_bytes() +
 135            (Register::number_of_registers - 3) *
 136            Register::max_slots_per_register *
 137            BytesPerInt;
 138   }
 139 };
 140 
 141 OopMap* RegisterSaver::save_live_registers(MacroAssembler* masm, int additional_frame_words, int* total_frame_words) {
 142   int vector_size_in_bytes = 0;
 143   int vector_size_in_slots = 0;
 144 #ifdef COMPILER2
 145   if (_save_vectors) {
 146     vector_size_in_bytes += Matcher::scalable_vector_reg_size(T_BYTE);
 147     vector_size_in_slots += Matcher::scalable_vector_reg_size(T_INT);
 148   }
 149 #endif
 150 
 151   int frame_size_in_bytes = align_up(additional_frame_words * wordSize + ra_offset_in_bytes() + wordSize, 16);
 152   // OopMap frame size is in compiler stack slots (jint's) not bytes or words
 153   int frame_size_in_slots = frame_size_in_bytes / BytesPerInt;
 154   // The caller will allocate additional_frame_words
 155   int additional_frame_slots = additional_frame_words * wordSize / BytesPerInt;
 156   // CodeBlob frame size is in words.
 157   int frame_size_in_words = frame_size_in_bytes / wordSize;
 158   *total_frame_words = frame_size_in_words;
 159 
 160   // Save Integer, Float and Vector registers.
 161   __ enter();
 162   __ push_CPU_state(_save_vectors, vector_size_in_bytes);
 163 
 164   // Set an oopmap for the call site.  This oopmap will map all
 165   // oop-registers and debug-info registers as callee-saved.  This
 166   // will allow deoptimization at this safepoint to find all possible
 167   // debug-info recordings, as well as let GC find all oops.
 168 
 169   OopMapSet *oop_maps = new OopMapSet();
 170   OopMap* oop_map = new OopMap(frame_size_in_slots, 0);
 171   assert_cond(oop_maps != nullptr && oop_map != nullptr);
 172 
 173   int sp_offset_in_slots = 0;
 174   int step_in_slots = 0;
 175   if (_save_vectors) {
 176     step_in_slots = vector_size_in_slots;
 177     for (int i = 0; i < VectorRegister::number_of_registers; i++, sp_offset_in_slots += step_in_slots) {
 178       VectorRegister r = as_VectorRegister(i);
 179       oop_map->set_callee_saved(VMRegImpl::stack2reg(sp_offset_in_slots), r->as_VMReg());
 180     }
 181   }
 182 
 183   step_in_slots = FloatRegister::max_slots_per_register;
 184   for (int i = 0; i < FloatRegister::number_of_registers; i++, sp_offset_in_slots += step_in_slots) {
 185     FloatRegister r = as_FloatRegister(i);
 186     oop_map->set_callee_saved(VMRegImpl::stack2reg(sp_offset_in_slots), r->as_VMReg());
 187   }
 188 
 189   step_in_slots = Register::max_slots_per_register;
 190   // skip the slot reserved for alignment, see MacroAssembler::push_reg;
 191   // also skip x5 ~ x6 on the stack because they are caller-saved registers.
 192   sp_offset_in_slots += Register::max_slots_per_register * 3;
 193   // besides, we ignore x0 ~ x4 because push_CPU_state won't push them on the stack.
 194   for (int i = 7; i < Register::number_of_registers; i++, sp_offset_in_slots += step_in_slots) {
 195     Register r = as_Register(i);
 196     if (r != xthread) {
 197       oop_map->set_callee_saved(VMRegImpl::stack2reg(sp_offset_in_slots + additional_frame_slots), r->as_VMReg());
 198     }
 199   }
 200 
 201   return oop_map;
 202 }
 203 
 204 void RegisterSaver::restore_live_registers(MacroAssembler* masm) {
 205 #ifdef COMPILER2
 206   __ pop_CPU_state(_save_vectors, Matcher::scalable_vector_reg_size(T_BYTE));
 207 #else
 208 #if !INCLUDE_JVMCI
 209   assert(!_save_vectors, "vectors are generated only by C2 and JVMCI");
 210 #endif
 211   __ pop_CPU_state(_save_vectors);
 212 #endif
 213   __ leave();
 214 }
 215 
 216 // Is vector's size (in bytes) bigger than a size saved by default?
 217 // riscv does not ovlerlay the floating-point registers on vector registers like aarch64.
 218 bool SharedRuntime::is_wide_vector(int size) {
 219   return UseRVV && size > 0;
 220 }
 221 
 222 // ---------------------------------------------------------------------------
 223 // Read the array of BasicTypes from a signature, and compute where the
 224 // arguments should go.  Values in the VMRegPair regs array refer to 4-byte
 225 // quantities.  Values less than VMRegImpl::stack0 are registers, those above
 226 // refer to 4-byte stack slots.  All stack slots are based off of the stack pointer
 227 // as framesizes are fixed.
 228 // VMRegImpl::stack0 refers to the first slot 0(sp).
 229 // and VMRegImpl::stack0+1 refers to the memory word 4-byes higher.
 230 // Register up to Register::number_of_registers) are the 64-bit
 231 // integer registers.
 232 
 233 // Note: the INPUTS in sig_bt are in units of Java argument words,
 234 // which are 64-bit.  The OUTPUTS are in 32-bit units.
 235 
 236 // The Java calling convention is a "shifted" version of the C ABI.
 237 // By skipping the first C ABI register we can call non-static jni
 238 // methods with small numbers of arguments without having to shuffle
 239 // the arguments at all. Since we control the java ABI we ought to at
 240 // least get some advantage out of it.
 241 
 242 int SharedRuntime::java_calling_convention(const BasicType *sig_bt,
 243                                            VMRegPair *regs,
 244                                            int total_args_passed) {
 245   // Create the mapping between argument positions and
 246   // registers.
 247   static const Register INT_ArgReg[Argument::n_int_register_parameters_j] = {
 248     j_rarg0, j_rarg1, j_rarg2, j_rarg3,
 249     j_rarg4, j_rarg5, j_rarg6, j_rarg7
 250   };
 251   static const FloatRegister FP_ArgReg[Argument::n_float_register_parameters_j] = {
 252     j_farg0, j_farg1, j_farg2, j_farg3,
 253     j_farg4, j_farg5, j_farg6, j_farg7
 254   };
 255 
 256   uint int_args = 0;
 257   uint fp_args = 0;
 258   uint stk_args = 0;
 259 
 260   for (int i = 0; i < total_args_passed; i++) {
 261     switch (sig_bt[i]) {
 262       case T_BOOLEAN: // fall through
 263       case T_CHAR:    // fall through
 264       case T_BYTE:    // fall through
 265       case T_SHORT:   // fall through
 266       case T_INT:
 267         if (int_args < Argument::n_int_register_parameters_j) {
 268           regs[i].set1(INT_ArgReg[int_args++]->as_VMReg());
 269         } else {
 270           stk_args = align_up(stk_args, 2);
 271           regs[i].set1(VMRegImpl::stack2reg(stk_args));
 272           stk_args += 1;
 273         }
 274         break;
 275       case T_VOID:
 276         // halves of T_LONG or T_DOUBLE
 277         assert(i != 0 && (sig_bt[i - 1] == T_LONG || sig_bt[i - 1] == T_DOUBLE), "expecting half");
 278         regs[i].set_bad();
 279         break;
 280       case T_LONG:      // fall through
 281         assert((i + 1) < total_args_passed && sig_bt[i + 1] == T_VOID, "expecting half");
 282       case T_OBJECT:    // fall through
 283       case T_ARRAY:     // fall through
 284       case T_ADDRESS:
 285         if (int_args < Argument::n_int_register_parameters_j) {
 286           regs[i].set2(INT_ArgReg[int_args++]->as_VMReg());
 287         } else {
 288           stk_args = align_up(stk_args, 2);
 289           regs[i].set2(VMRegImpl::stack2reg(stk_args));
 290           stk_args += 2;
 291         }
 292         break;
 293       case T_FLOAT:
 294         if (fp_args < Argument::n_float_register_parameters_j) {
 295           regs[i].set1(FP_ArgReg[fp_args++]->as_VMReg());
 296         } else {
 297           stk_args = align_up(stk_args, 2);
 298           regs[i].set1(VMRegImpl::stack2reg(stk_args));
 299           stk_args += 1;
 300         }
 301         break;
 302       case T_DOUBLE:
 303         assert((i + 1) < total_args_passed && sig_bt[i + 1] == T_VOID, "expecting half");
 304         if (fp_args < Argument::n_float_register_parameters_j) {
 305           regs[i].set2(FP_ArgReg[fp_args++]->as_VMReg());
 306         } else {
 307           stk_args = align_up(stk_args, 2);
 308           regs[i].set2(VMRegImpl::stack2reg(stk_args));
 309           stk_args += 2;
 310         }
 311         break;
 312       default:
 313         ShouldNotReachHere();
 314     }
 315   }
 316 
 317   return stk_args;
 318 }
 319 
 320 // Patch the callers callsite with entry to compiled code if it exists.
 321 static void patch_callers_callsite(MacroAssembler *masm) {
 322   Label L;
 323   __ ld(t0, Address(xmethod, in_bytes(Method::code_offset())));
 324   __ beqz(t0, L);
 325 
 326   __ enter();
 327   __ push_CPU_state();
 328 
 329   // VM needs caller's callsite
 330   // VM needs target method
 331   // This needs to be a long call since we will relocate this adapter to
 332   // the codeBuffer and it may not reach
 333 
 334 #ifndef PRODUCT
 335   assert(frame::arg_reg_save_area_bytes == 0, "not expecting frame reg save area");
 336 #endif
 337 
 338   __ mv(c_rarg0, xmethod);
 339   __ mv(c_rarg1, ra);
 340   __ rt_call(CAST_FROM_FN_PTR(address, SharedRuntime::fixup_callers_callsite));
 341 
 342   __ pop_CPU_state();
 343   // restore sp
 344   __ leave();
 345   __ bind(L);
 346 }
 347 
 348 static void gen_c2i_adapter(MacroAssembler *masm,
 349                             int total_args_passed,
 350                             int comp_args_on_stack,
 351                             const BasicType *sig_bt,
 352                             const VMRegPair *regs,
 353                             Label& skip_fixup) {
 354   // Before we get into the guts of the C2I adapter, see if we should be here
 355   // at all.  We've come from compiled code and are attempting to jump to the
 356   // interpreter, which means the caller made a static call to get here
 357   // (vcalls always get a compiled target if there is one).  Check for a
 358   // compiled target.  If there is one, we need to patch the caller's call.
 359   patch_callers_callsite(masm);
 360 
 361   __ bind(skip_fixup);
 362 
 363   int words_pushed = 0;
 364 
 365   // Since all args are passed on the stack, total_args_passed *
 366   // Interpreter::stackElementSize is the space we need.
 367 
 368   int extraspace = total_args_passed * Interpreter::stackElementSize;
 369 
 370   __ mv(x19_sender_sp, sp);
 371 
 372   // stack is aligned, keep it that way
 373   extraspace = align_up(extraspace, 2 * wordSize);
 374 
 375   if (extraspace) {
 376     __ sub(sp, sp, extraspace);
 377   }
 378 
 379   // Now write the args into the outgoing interpreter space
 380   for (int i = 0; i < total_args_passed; i++) {
 381     if (sig_bt[i] == T_VOID) {
 382       assert(i > 0 && (sig_bt[i - 1] == T_LONG || sig_bt[i - 1] == T_DOUBLE), "missing half");
 383       continue;
 384     }
 385 
 386     // offset to start parameters
 387     int st_off   = (total_args_passed - i - 1) * Interpreter::stackElementSize;
 388     int next_off = st_off - Interpreter::stackElementSize;
 389 
 390     // Say 4 args:
 391     // i   st_off
 392     // 0   32 T_LONG
 393     // 1   24 T_VOID
 394     // 2   16 T_OBJECT
 395     // 3    8 T_BOOL
 396     // -    0 return address
 397     //
 398     // However to make thing extra confusing. Because we can fit a Java long/double in
 399     // a single slot on a 64 bt vm and it would be silly to break them up, the interpreter
 400     // leaves one slot empty and only stores to a single slot. In this case the
 401     // slot that is occupied is the T_VOID slot. See I said it was confusing.
 402 
 403     VMReg r_1 = regs[i].first();
 404     VMReg r_2 = regs[i].second();
 405     if (!r_1->is_valid()) {
 406       assert(!r_2->is_valid(), "");
 407       continue;
 408     }
 409     if (r_1->is_stack()) {
 410       // memory to memory use t0
 411       int ld_off = (r_1->reg2stack() * VMRegImpl::stack_slot_size
 412                     + extraspace
 413                     + words_pushed * wordSize);
 414       if (!r_2->is_valid()) {
 415         __ lwu(t0, Address(sp, ld_off));
 416         __ sd(t0, Address(sp, st_off), /*temp register*/esp);
 417       } else {
 418         __ ld(t0, Address(sp, ld_off), /*temp register*/esp);
 419 
 420         // Two VMREgs|OptoRegs can be T_OBJECT, T_ADDRESS, T_DOUBLE, T_LONG
 421         // T_DOUBLE and T_LONG use two slots in the interpreter
 422         if (sig_bt[i] == T_LONG || sig_bt[i] == T_DOUBLE) {
 423           // ld_off == LSW, ld_off+wordSize == MSW
 424           // st_off == MSW, next_off == LSW
 425           __ sd(t0, Address(sp, next_off), /*temp register*/esp);
 426 #ifdef ASSERT
 427           // Overwrite the unused slot with known junk
 428           __ mv(t0, 0xdeadffffdeadaaaaul);
 429           __ sd(t0, Address(sp, st_off), /*temp register*/esp);
 430 #endif /* ASSERT */
 431         } else {
 432           __ sd(t0, Address(sp, st_off), /*temp register*/esp);
 433         }
 434       }
 435     } else if (r_1->is_Register()) {
 436       Register r = r_1->as_Register();
 437       if (!r_2->is_valid()) {
 438         // must be only an int (or less ) so move only 32bits to slot
 439         __ sd(r, Address(sp, st_off));
 440       } else {
 441         // Two VMREgs|OptoRegs can be T_OBJECT, T_ADDRESS, T_DOUBLE, T_LONG
 442         // T_DOUBLE and T_LONG use two slots in the interpreter
 443         if ( sig_bt[i] == T_LONG || sig_bt[i] == T_DOUBLE) {
 444           // long/double in gpr
 445 #ifdef ASSERT
 446           // Overwrite the unused slot with known junk
 447           __ mv(t0, 0xdeadffffdeadaaabul);
 448           __ sd(t0, Address(sp, st_off), /*temp register*/esp);
 449 #endif /* ASSERT */
 450           __ sd(r, Address(sp, next_off));
 451         } else {
 452           __ sd(r, Address(sp, st_off));
 453         }
 454       }
 455     } else {
 456       assert(r_1->is_FloatRegister(), "");
 457       if (!r_2->is_valid()) {
 458         // only a float use just part of the slot
 459         __ fsw(r_1->as_FloatRegister(), Address(sp, st_off));
 460       } else {
 461 #ifdef ASSERT
 462         // Overwrite the unused slot with known junk
 463         __ mv(t0, 0xdeadffffdeadaaacul);
 464         __ sd(t0, Address(sp, st_off), /*temp register*/esp);
 465 #endif /* ASSERT */
 466         __ fsd(r_1->as_FloatRegister(), Address(sp, next_off));
 467       }
 468     }
 469   }
 470 
 471   __ mv(esp, sp); // Interp expects args on caller's expression stack
 472 
 473   __ ld(t1, Address(xmethod, in_bytes(Method::interpreter_entry_offset())));
 474   __ jr(t1);
 475 }
 476 
 477 void SharedRuntime::gen_i2c_adapter(MacroAssembler *masm,
 478                                     int total_args_passed,
 479                                     int comp_args_on_stack,
 480                                     const BasicType *sig_bt,
 481                                     const VMRegPair *regs) {
 482   // Note: x19_sender_sp contains the senderSP on entry. We must
 483   // preserve it since we may do a i2c -> c2i transition if we lose a
 484   // race where compiled code goes non-entrant while we get args
 485   // ready.
 486 
 487   // Cut-out for having no stack args.
 488   int comp_words_on_stack = align_up(comp_args_on_stack * VMRegImpl::stack_slot_size, wordSize) >> LogBytesPerWord;
 489   if (comp_args_on_stack != 0) {
 490     __ sub(t0, sp, comp_words_on_stack * wordSize);
 491     __ andi(sp, t0, -16);
 492   }
 493 
 494   // Will jump to the compiled code just as if compiled code was doing it.
 495   // Pre-load the register-jump target early, to schedule it better.
 496   __ ld(t1, Address(xmethod, in_bytes(Method::from_compiled_offset())));
 497 
 498 #if INCLUDE_JVMCI
 499   if (EnableJVMCI) {
 500     // check if this call should be routed towards a specific entry point
 501     __ ld(t0, Address(xthread, in_bytes(JavaThread::jvmci_alternate_call_target_offset())));
 502     Label no_alternative_target;
 503     __ beqz(t0, no_alternative_target);
 504     __ mv(t1, t0);
 505     __ sd(zr, Address(xthread, in_bytes(JavaThread::jvmci_alternate_call_target_offset())));
 506     __ bind(no_alternative_target);
 507   }
 508 #endif // INCLUDE_JVMCI
 509 
 510   // Now generate the shuffle code.
 511   for (int i = 0; i < total_args_passed; i++) {
 512     if (sig_bt[i] == T_VOID) {
 513       assert(i > 0 && (sig_bt[i - 1] == T_LONG || sig_bt[i - 1] == T_DOUBLE), "missing half");
 514       continue;
 515     }
 516 
 517     // Pick up 0, 1 or 2 words from SP+offset.
 518 
 519     assert(!regs[i].second()->is_valid() || regs[i].first()->next() == regs[i].second(),
 520            "scrambled load targets?");
 521     // Load in argument order going down.
 522     int ld_off = (total_args_passed - i - 1) * Interpreter::stackElementSize;
 523     // Point to interpreter value (vs. tag)
 524     int next_off = ld_off - Interpreter::stackElementSize;
 525 
 526     VMReg r_1 = regs[i].first();
 527     VMReg r_2 = regs[i].second();
 528     if (!r_1->is_valid()) {
 529       assert(!r_2->is_valid(), "");
 530       continue;
 531     }
 532     if (r_1->is_stack()) {
 533       // Convert stack slot to an SP offset (+ wordSize to account for return address )
 534       int st_off = regs[i].first()->reg2stack() * VMRegImpl::stack_slot_size;
 535       if (!r_2->is_valid()) {
 536         __ lw(t0, Address(esp, ld_off));
 537         __ sd(t0, Address(sp, st_off), /*temp register*/t2);
 538       } else {
 539         //
 540         // We are using two optoregs. This can be either T_OBJECT,
 541         // T_ADDRESS, T_LONG, or T_DOUBLE the interpreter allocates
 542         // two slots but only uses one for thr T_LONG or T_DOUBLE case
 543         // So we must adjust where to pick up the data to match the
 544         // interpreter.
 545         //
 546         // Interpreter local[n] == MSW, local[n+1] == LSW however locals
 547         // are accessed as negative so LSW is at LOW address
 548 
 549         // ld_off is MSW so get LSW
 550         const int offset = (sig_bt[i] == T_LONG || sig_bt[i] == T_DOUBLE) ?
 551                            next_off : ld_off;
 552         __ ld(t0, Address(esp, offset));
 553         // st_off is LSW (i.e. reg.first())
 554         __ sd(t0, Address(sp, st_off), /*temp register*/t2);
 555       }
 556     } else if (r_1->is_Register()) {  // Register argument
 557       Register r = r_1->as_Register();
 558       if (r_2->is_valid()) {
 559         //
 560         // We are using two VMRegs. This can be either T_OBJECT,
 561         // T_ADDRESS, T_LONG, or T_DOUBLE the interpreter allocates
 562         // two slots but only uses one for thr T_LONG or T_DOUBLE case
 563         // So we must adjust where to pick up the data to match the
 564         // interpreter.
 565 
 566         const int offset = (sig_bt[i] == T_LONG || sig_bt[i] == T_DOUBLE) ?
 567                            next_off : ld_off;
 568 
 569         // this can be a misaligned move
 570         __ ld(r, Address(esp, offset));
 571       } else {
 572         // sign extend and use a full word?
 573         __ lw(r, Address(esp, ld_off));
 574       }
 575     } else {
 576       if (!r_2->is_valid()) {
 577         __ flw(r_1->as_FloatRegister(), Address(esp, ld_off));
 578       } else {
 579         __ fld(r_1->as_FloatRegister(), Address(esp, next_off));
 580       }
 581     }
 582   }
 583 
 584   __ push_cont_fastpath(xthread); // Set JavaThread::_cont_fastpath to the sp of the oldest interpreted frame we know about
 585 
 586   // 6243940 We might end up in handle_wrong_method if
 587   // the callee is deoptimized as we race thru here. If that
 588   // happens we don't want to take a safepoint because the
 589   // caller frame will look interpreted and arguments are now
 590   // "compiled" so it is much better to make this transition
 591   // invisible to the stack walking code. Unfortunately if
 592   // we try and find the callee by normal means a safepoint
 593   // is possible. So we stash the desired callee in the thread
 594   // and the vm will find there should this case occur.
 595 
 596   __ sd(xmethod, Address(xthread, JavaThread::callee_target_offset()));
 597 
 598   __ jr(t1);
 599 }
 600 
 601 // ---------------------------------------------------------------
 602 
 603 void SharedRuntime::generate_i2c2i_adapters(MacroAssembler *masm,
 604                                             int total_args_passed,
 605                                             int comp_args_on_stack,
 606                                             const BasicType *sig_bt,
 607                                             const VMRegPair *regs,
 608                                             address entry_address[AdapterBlob::ENTRY_COUNT]) {
 609   entry_address[AdapterBlob::I2C] = __ pc();
 610   gen_i2c_adapter(masm, total_args_passed, comp_args_on_stack, sig_bt, regs);
 611 
 612   entry_address[AdapterBlob::C2I_Unverified] = __ pc();
 613   Label skip_fixup;
 614 
 615   const Register receiver = j_rarg0;
 616   const Register data = t0;
 617 
 618   // -------------------------------------------------------------------------
 619   // Generate a C2I adapter.  On entry we know xmethod holds the Method* during calls
 620   // to the interpreter.  The args start out packed in the compiled layout.  They
 621   // need to be unpacked into the interpreter layout.  This will almost always
 622   // require some stack space.  We grow the current (compiled) stack, then repack
 623   // the args.  We  finally end in a jump to the generic interpreter entry point.
 624   // On exit from the interpreter, the interpreter will restore our SP (lest the
 625   // compiled code, which relies solely on SP and not FP, get sick).
 626 
 627   {
 628     __ block_comment("c2i_unverified_entry {");
 629 
 630     __ ic_check();
 631     __ ld(xmethod, Address(data, CompiledICData::speculated_method_offset()));
 632 
 633     __ ld(t0, Address(xmethod, in_bytes(Method::code_offset())));
 634     __ beqz(t0, skip_fixup);
 635     __ far_jump(RuntimeAddress(SharedRuntime::get_ic_miss_stub()));
 636     __ block_comment("} c2i_unverified_entry");
 637   }
 638 
 639   entry_address[AdapterBlob::C2I] = __ pc();
 640 
 641   // Class initialization barrier for static methods
 642   entry_address[AdapterBlob::C2I_No_Clinit_Check] = nullptr;
 643   assert(VM_Version::supports_fast_class_init_checks(), "sanity");
 644   Label L_skip_barrier;
 645 
 646   // Bypass the barrier for non-static methods
 647   __ load_unsigned_short(t0, Address(xmethod, Method::access_flags_offset()));
 648   __ test_bit(t1, t0, exact_log2(JVM_ACC_STATIC));
 649   __ beqz(t1, L_skip_barrier); // non-static
 650 
 651   __ load_method_holder(t1, xmethod);
 652   __ clinit_barrier(t1, t0, &L_skip_barrier);
 653   __ far_jump(RuntimeAddress(SharedRuntime::get_handle_wrong_method_stub()));
 654 
 655   __ bind(L_skip_barrier);
 656   entry_address[AdapterBlob::C2I_No_Clinit_Check] = __ pc();
 657 
 658   BarrierSetAssembler* bs = BarrierSet::barrier_set()->barrier_set_assembler();
 659   bs->c2i_entry_barrier(masm);
 660 
 661   gen_c2i_adapter(masm, total_args_passed, comp_args_on_stack, sig_bt, regs, skip_fixup);
 662   return;
 663 }
 664 
 665 int SharedRuntime::vector_calling_convention(VMRegPair *regs,
 666                                              uint num_bits,
 667                                              uint total_args_passed) {
 668   assert(total_args_passed <= Argument::n_vector_register_parameters_c, "unsupported");
 669   assert(num_bits >= 64 && num_bits <= 2048 && is_power_of_2(num_bits), "unsupported");
 670 
 671   // check more info at https://github.com/riscv-non-isa/riscv-elf-psabi-doc/blob/master/riscv-cc.adoc
 672   static const VectorRegister VEC_ArgReg[Argument::n_vector_register_parameters_c] = {
 673     v8, v9, v10, v11, v12, v13, v14, v15,
 674     v16, v17, v18, v19, v20, v21, v22, v23
 675   };
 676 
 677   const int next_reg_val = 3;
 678   for (uint i = 0; i < total_args_passed; i++) {
 679     VMReg vmreg = VEC_ArgReg[i]->as_VMReg();
 680     regs[i].set_pair(vmreg->next(next_reg_val), vmreg);
 681   }
 682   return 0;
 683 }
 684 
 685 int SharedRuntime::c_calling_convention(const BasicType *sig_bt,
 686                                          VMRegPair *regs,
 687                                          int total_args_passed) {
 688 
 689   // We return the amount of VMRegImpl stack slots we need to reserve for all
 690   // the arguments NOT counting out_preserve_stack_slots.
 691 
 692   static const Register INT_ArgReg[Argument::n_int_register_parameters_c] = {
 693     c_rarg0, c_rarg1, c_rarg2, c_rarg3,
 694     c_rarg4, c_rarg5,  c_rarg6,  c_rarg7
 695   };
 696   static const FloatRegister FP_ArgReg[Argument::n_float_register_parameters_c] = {
 697     c_farg0, c_farg1, c_farg2, c_farg3,
 698     c_farg4, c_farg5, c_farg6, c_farg7
 699   };
 700 
 701   uint int_args = 0;
 702   uint fp_args = 0;
 703   uint stk_args = 0; // inc by 2 each time
 704 
 705   for (int i = 0; i < total_args_passed; i++) {
 706     switch (sig_bt[i]) {
 707       case T_BOOLEAN:  // fall through
 708       case T_CHAR:     // fall through
 709       case T_BYTE:     // fall through
 710       case T_SHORT:    // fall through
 711       case T_INT:
 712         if (int_args < Argument::n_int_register_parameters_c) {
 713           regs[i].set1(INT_ArgReg[int_args++]->as_VMReg());
 714         } else {
 715           regs[i].set1(VMRegImpl::stack2reg(stk_args));
 716           stk_args += 2;
 717         }
 718         break;
 719       case T_LONG:      // fall through
 720         assert((i + 1) < total_args_passed && sig_bt[i + 1] == T_VOID, "expecting half");
 721       case T_OBJECT:    // fall through
 722       case T_ARRAY:     // fall through
 723       case T_ADDRESS:   // fall through
 724       case T_METADATA:
 725         if (int_args < Argument::n_int_register_parameters_c) {
 726           regs[i].set2(INT_ArgReg[int_args++]->as_VMReg());
 727         } else {
 728           regs[i].set2(VMRegImpl::stack2reg(stk_args));
 729           stk_args += 2;
 730         }
 731         break;
 732       case T_FLOAT:
 733         if (fp_args < Argument::n_float_register_parameters_c) {
 734           regs[i].set1(FP_ArgReg[fp_args++]->as_VMReg());
 735         } else if (int_args < Argument::n_int_register_parameters_c) {
 736           regs[i].set1(INT_ArgReg[int_args++]->as_VMReg());
 737         } else {
 738           regs[i].set1(VMRegImpl::stack2reg(stk_args));
 739           stk_args += 2;
 740         }
 741         break;
 742       case T_DOUBLE:
 743         assert((i + 1) < total_args_passed && sig_bt[i + 1] == T_VOID, "expecting half");
 744         if (fp_args < Argument::n_float_register_parameters_c) {
 745           regs[i].set2(FP_ArgReg[fp_args++]->as_VMReg());
 746         } else if (int_args < Argument::n_int_register_parameters_c) {
 747           regs[i].set2(INT_ArgReg[int_args++]->as_VMReg());
 748         } else {
 749           regs[i].set2(VMRegImpl::stack2reg(stk_args));
 750           stk_args += 2;
 751         }
 752         break;
 753       case T_VOID: // Halves of longs and doubles
 754         assert(i != 0 && (sig_bt[i - 1] == T_LONG || sig_bt[i - 1] == T_DOUBLE), "expecting half");
 755         regs[i].set_bad();
 756         break;
 757       default:
 758         ShouldNotReachHere();
 759     }
 760   }
 761 
 762   return stk_args;
 763 }
 764 
 765 void SharedRuntime::save_native_result(MacroAssembler *masm, BasicType ret_type, int frame_slots) {
 766   // We always ignore the frame_slots arg and just use the space just below frame pointer
 767   // which by this time is free to use
 768   switch (ret_type) {
 769     case T_FLOAT:
 770       __ fsw(f10, Address(fp, -3 * wordSize));
 771       break;
 772     case T_DOUBLE:
 773       __ fsd(f10, Address(fp, -3 * wordSize));
 774       break;
 775     case T_VOID:  break;
 776     default: {
 777       __ sd(x10, Address(fp, -3 * wordSize));
 778     }
 779   }
 780 }
 781 
 782 void SharedRuntime::restore_native_result(MacroAssembler *masm, BasicType ret_type, int frame_slots) {
 783   // We always ignore the frame_slots arg and just use the space just below frame pointer
 784   // which by this time is free to use
 785   switch (ret_type) {
 786     case T_FLOAT:
 787       __ flw(f10, Address(fp, -3 * wordSize));
 788       break;
 789     case T_DOUBLE:
 790       __ fld(f10, Address(fp, -3 * wordSize));
 791       break;
 792     case T_VOID:  break;
 793     default: {
 794       __ ld(x10, Address(fp, -3 * wordSize));
 795     }
 796   }
 797 }
 798 
 799 static void save_args(MacroAssembler *masm, int arg_count, int first_arg, VMRegPair *args) {
 800   RegSet x;
 801   for ( int i = first_arg ; i < arg_count ; i++ ) {
 802     if (args[i].first()->is_Register()) {
 803       x = x + args[i].first()->as_Register();
 804     } else if (args[i].first()->is_FloatRegister()) {
 805       __ subi(sp, sp, 2 * wordSize);
 806       __ fsd(args[i].first()->as_FloatRegister(), Address(sp, 0));
 807     }
 808   }
 809   __ push_reg(x, sp);
 810 }
 811 
 812 static void restore_args(MacroAssembler *masm, int arg_count, int first_arg, VMRegPair *args) {
 813   RegSet x;
 814   for ( int i = first_arg ; i < arg_count ; i++ ) {
 815     if (args[i].first()->is_Register()) {
 816       x = x + args[i].first()->as_Register();
 817     } else {
 818       ;
 819     }
 820   }
 821   __ pop_reg(x, sp);
 822   for ( int i = arg_count - 1 ; i >= first_arg ; i-- ) {
 823     if (args[i].first()->is_Register()) {
 824       ;
 825     } else if (args[i].first()->is_FloatRegister()) {
 826       __ fld(args[i].first()->as_FloatRegister(), Address(sp, 0));
 827       __ addi(sp, sp, 2 * wordSize);
 828     }
 829   }
 830 }
 831 
 832 static void verify_oop_args(MacroAssembler* masm,
 833                             const methodHandle& method,
 834                             const BasicType* sig_bt,
 835                             const VMRegPair* regs) {
 836   const Register temp_reg = x9;  // not part of any compiled calling seq
 837   if (VerifyOops) {
 838     for (int i = 0; i < method->size_of_parameters(); i++) {
 839       if (sig_bt[i] == T_OBJECT ||
 840           sig_bt[i] == T_ARRAY) {
 841         VMReg r = regs[i].first();
 842         assert(r->is_valid(), "bad oop arg");
 843         if (r->is_stack()) {
 844           __ ld(temp_reg, Address(sp, r->reg2stack() * VMRegImpl::stack_slot_size));
 845           __ verify_oop(temp_reg);
 846         } else {
 847           __ verify_oop(r->as_Register());
 848         }
 849       }
 850     }
 851   }
 852 }
 853 
 854 // on exit, sp points to the ContinuationEntry
 855 static OopMap* continuation_enter_setup(MacroAssembler* masm, int& stack_slots) {
 856   assert(ContinuationEntry::size() % VMRegImpl::stack_slot_size == 0, "");
 857   assert(in_bytes(ContinuationEntry::cont_offset())  % VMRegImpl::stack_slot_size == 0, "");
 858   assert(in_bytes(ContinuationEntry::chunk_offset()) % VMRegImpl::stack_slot_size == 0, "");
 859 
 860   stack_slots += (int)ContinuationEntry::size() / wordSize;
 861   __ sub(sp, sp, (int)ContinuationEntry::size()); // place Continuation metadata
 862 
 863   OopMap* map = new OopMap(((int)ContinuationEntry::size() + wordSize) / VMRegImpl::stack_slot_size, 0 /* arg_slots*/);
 864 
 865   __ ld(t0, Address(xthread, JavaThread::cont_entry_offset()));
 866   __ sd(t0, Address(sp, ContinuationEntry::parent_offset()));
 867   __ sd(sp, Address(xthread, JavaThread::cont_entry_offset()));
 868 
 869   return map;
 870 }
 871 
 872 // on entry c_rarg1 points to the continuation
 873 //          sp points to ContinuationEntry
 874 //          c_rarg3 -- isVirtualThread
 875 static void fill_continuation_entry(MacroAssembler* masm) {
 876 #ifdef ASSERT
 877   __ mv(t0, ContinuationEntry::cookie_value());
 878   __ sw(t0, Address(sp, ContinuationEntry::cookie_offset()));
 879 #endif
 880 
 881   __ sd(c_rarg1, Address(sp, ContinuationEntry::cont_offset()));
 882   __ sw(c_rarg3, Address(sp, ContinuationEntry::flags_offset()));
 883   __ sd(zr,      Address(sp, ContinuationEntry::chunk_offset()));
 884   __ sw(zr,      Address(sp, ContinuationEntry::argsize_offset()));
 885   __ sw(zr,      Address(sp, ContinuationEntry::pin_count_offset()));
 886 
 887   __ ld(t0, Address(xthread, JavaThread::cont_fastpath_offset()));
 888   __ sd(t0, Address(sp, ContinuationEntry::parent_cont_fastpath_offset()));
 889 
 890   __ sd(zr, Address(xthread, JavaThread::cont_fastpath_offset()));
 891 }
 892 
 893 // on entry, sp points to the ContinuationEntry
 894 // on exit, fp points to the spilled fp + 2 * wordSize in the entry frame
 895 static void continuation_enter_cleanup(MacroAssembler* masm) {
 896 #ifndef PRODUCT
 897   Label OK;
 898   __ ld(t0, Address(xthread, JavaThread::cont_entry_offset()));
 899   __ beq(sp, t0, OK);
 900   __ stop("incorrect sp");
 901   __ bind(OK);
 902 #endif
 903 
 904   __ ld(t0, Address(sp, ContinuationEntry::parent_cont_fastpath_offset()));
 905   __ sd(t0, Address(xthread, JavaThread::cont_fastpath_offset()));
 906   __ ld(t0, Address(sp, ContinuationEntry::parent_offset()));
 907   __ sd(t0, Address(xthread, JavaThread::cont_entry_offset()));
 908   __ add(fp, sp, (int)ContinuationEntry::size() + 2 * wordSize /* 2 extra words to match up with leave() */);
 909 }
 910 
 911 // enterSpecial(Continuation c, boolean isContinue, boolean isVirtualThread)
 912 // On entry: c_rarg1 -- the continuation object
 913 //           c_rarg2 -- isContinue
 914 //           c_rarg3 -- isVirtualThread
 915 static void gen_continuation_enter(MacroAssembler* masm,
 916                                    const methodHandle& method,
 917                                    const BasicType* sig_bt,
 918                                    const VMRegPair* regs,
 919                                    int& exception_offset,
 920                                    OopMapSet*oop_maps,
 921                                    int& frame_complete,
 922                                    int& stack_slots,
 923                                    int& interpreted_entry_offset,
 924                                    int& compiled_entry_offset) {
 925   // verify_oop_args(masm, method, sig_bt, regs);
 926   Address resolve(SharedRuntime::get_resolve_static_call_stub(), relocInfo::static_call_type);
 927 
 928   address start = __ pc();
 929 
 930   Label call_thaw, exit;
 931 
 932   // i2i entry used at interp_only_mode only
 933   interpreted_entry_offset = __ pc() - start;
 934   {
 935 #ifdef ASSERT
 936     Label is_interp_only;
 937     __ lw(t0, Address(xthread, JavaThread::interp_only_mode_offset()));
 938     __ bnez(t0, is_interp_only);
 939     __ stop("enterSpecial interpreter entry called when not in interp_only_mode");
 940     __ bind(is_interp_only);
 941 #endif
 942 
 943     // Read interpreter arguments into registers (this is an ad-hoc i2c adapter)
 944     __ ld(c_rarg1, Address(esp, Interpreter::stackElementSize * 2));
 945     __ ld(c_rarg2, Address(esp, Interpreter::stackElementSize * 1));
 946     __ ld(c_rarg3, Address(esp, Interpreter::stackElementSize * 0));
 947     __ push_cont_fastpath(xthread);
 948 
 949     __ enter();
 950     stack_slots = 2; // will be adjusted in setup
 951     OopMap* map = continuation_enter_setup(masm, stack_slots);
 952     // The frame is complete here, but we only record it for the compiled entry, so the frame would appear unsafe,
 953     // but that's okay because at the very worst we'll miss an async sample, but we're in interp_only_mode anyway.
 954 
 955     fill_continuation_entry(masm);
 956 
 957     __ bnez(c_rarg2, call_thaw);
 958 
 959     address call_pc;
 960     {
 961       Assembler::IncompressibleScope scope(masm);
 962       // Make sure the call is patchable
 963       __ align(NativeInstruction::instruction_size);
 964 
 965       call_pc = __ reloc_call(resolve);
 966       if (call_pc == nullptr) {
 967         fatal("CodeCache is full at gen_continuation_enter");
 968       }
 969 
 970       oop_maps->add_gc_map(__ pc() - start, map);
 971       __ post_call_nop();
 972     }
 973     __ j(exit);
 974 
 975     address stub = CompiledDirectCall::emit_to_interp_stub(masm, call_pc);
 976     if (stub == nullptr) {
 977       fatal("CodeCache is full at gen_continuation_enter");
 978     }
 979   }
 980 
 981   // compiled entry
 982   __ align(CodeEntryAlignment);
 983   compiled_entry_offset = __ pc() - start;
 984 
 985   __ enter();
 986   stack_slots = 2; // will be adjusted in setup
 987   OopMap* map = continuation_enter_setup(masm, stack_slots);
 988   frame_complete = __ pc() - start;
 989 
 990   fill_continuation_entry(masm);
 991 
 992   __ bnez(c_rarg2, call_thaw);
 993 
 994   address call_pc;
 995   {
 996     Assembler::IncompressibleScope scope(masm);
 997     // Make sure the call is patchable
 998     __ align(NativeInstruction::instruction_size);
 999 
1000     call_pc = __ reloc_call(resolve);
1001     if (call_pc == nullptr) {
1002       fatal("CodeCache is full at gen_continuation_enter");
1003     }
1004 
1005     oop_maps->add_gc_map(__ pc() - start, map);
1006     __ post_call_nop();
1007   }
1008 
1009   __ j(exit);
1010 
1011   __ bind(call_thaw);
1012 
1013   // Post call nops must be natural aligned due to cmodx rules.
1014   {
1015     Assembler::IncompressibleScope scope(masm);
1016     __ align(NativeInstruction::instruction_size);
1017 
1018     ContinuationEntry::_thaw_call_pc_offset = __ pc() - start;
1019     __ rt_call(CAST_FROM_FN_PTR(address, StubRoutines::cont_thaw()));
1020     oop_maps->add_gc_map(__ pc() - start, map->deep_copy());
1021     ContinuationEntry::_return_pc_offset = __ pc() - start;
1022     __ post_call_nop();
1023   }
1024 
1025   __ bind(exit);
1026   ContinuationEntry::_cleanup_offset = __ pc() - start;
1027   continuation_enter_cleanup(masm);
1028   __ leave();
1029   __ ret();
1030 
1031   // exception handling
1032   exception_offset = __ pc() - start;
1033   {
1034     __ mv(x9, x10); // save return value contaning the exception oop in callee-saved x9
1035 
1036     continuation_enter_cleanup(masm);
1037 
1038     __ ld(c_rarg1, Address(fp, -1 * wordSize)); // return address
1039     __ call_VM_leaf(CAST_FROM_FN_PTR(address, SharedRuntime::exception_handler_for_return_address), xthread, c_rarg1);
1040 
1041     // see OptoRuntime::generate_exception_blob: x10 -- exception oop, x13 -- exception pc
1042 
1043     __ mv(x11, x10); // the exception handler
1044     __ mv(x10, x9); // restore return value contaning the exception oop
1045     __ verify_oop(x10);
1046 
1047     __ leave();
1048     __ mv(x13, ra);
1049     __ jr(x11); // the exception handler
1050   }
1051 
1052   address stub = CompiledDirectCall::emit_to_interp_stub(masm, call_pc);
1053   if (stub == nullptr) {
1054     fatal("CodeCache is full at gen_continuation_enter");
1055   }
1056 }
1057 
1058 static void gen_continuation_yield(MacroAssembler* masm,
1059                                    const methodHandle& method,
1060                                    const BasicType* sig_bt,
1061                                    const VMRegPair* regs,
1062                                    OopMapSet* oop_maps,
1063                                    int& frame_complete,
1064                                    int& stack_slots,
1065                                    int& compiled_entry_offset) {
1066   enum layout {
1067     fp_off,
1068     fp_off2,
1069     return_off,
1070     return_off2,
1071     framesize // inclusive of return address
1072   };
1073   // assert(is_even(framesize/2), "sp not 16-byte aligned");
1074 
1075   stack_slots = framesize / VMRegImpl::slots_per_word;
1076   assert(stack_slots == 2, "recheck layout");
1077 
1078   address start = __ pc();
1079 
1080   compiled_entry_offset = __ pc() - start;
1081   __ enter();
1082 
1083   __ mv(c_rarg1, sp);
1084 
1085   // Post call nops must be natural aligned due to cmodx rules.
1086   __ align(NativeInstruction::instruction_size);
1087 
1088   frame_complete = __ pc() - start;
1089   address the_pc = __ pc();
1090 
1091   {
1092     Assembler::IncompressibleScope scope(masm);
1093     __ 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
1094   }
1095 
1096   __ mv(c_rarg0, xthread);
1097   __ set_last_Java_frame(sp, fp, the_pc, t0);
1098   __ call_VM_leaf(Continuation::freeze_entry(), 2);
1099   __ reset_last_Java_frame(true);
1100 
1101   Label pinned;
1102 
1103   __ bnez(x10, pinned);
1104 
1105   // We've succeeded, set sp to the ContinuationEntry
1106   __ ld(sp, Address(xthread, JavaThread::cont_entry_offset()));
1107   continuation_enter_cleanup(masm);
1108 
1109   __ bind(pinned); // pinned -- return to caller
1110 
1111   // handle pending exception thrown by freeze
1112   __ ld(t0, Address(xthread, in_bytes(Thread::pending_exception_offset())));
1113   Label ok;
1114   __ beqz(t0, ok);
1115   __ leave();
1116   __ j(RuntimeAddress(StubRoutines::forward_exception_entry()));
1117   __ bind(ok);
1118 
1119   __ leave();
1120   __ ret();
1121 
1122   OopMap* map = new OopMap(framesize, 1);
1123   oop_maps->add_gc_map(the_pc - start, map);
1124 }
1125 
1126 void SharedRuntime::continuation_enter_cleanup(MacroAssembler* masm) {
1127   ::continuation_enter_cleanup(masm);
1128 }
1129 
1130 static void gen_special_dispatch(MacroAssembler* masm,
1131                                  const methodHandle& method,
1132                                  const BasicType* sig_bt,
1133                                  const VMRegPair* regs) {
1134   verify_oop_args(masm, method, sig_bt, regs);
1135   vmIntrinsics::ID iid = method->intrinsic_id();
1136 
1137   // Now write the args into the outgoing interpreter space
1138   bool     has_receiver   = false;
1139   Register receiver_reg   = noreg;
1140   int      member_arg_pos = -1;
1141   Register member_reg     = noreg;
1142   int      ref_kind       = MethodHandles::signature_polymorphic_intrinsic_ref_kind(iid);
1143   if (ref_kind != 0) {
1144     member_arg_pos = method->size_of_parameters() - 1;  // trailing MemberName argument
1145     member_reg = x9;  // known to be free at this point
1146     has_receiver = MethodHandles::ref_kind_has_receiver(ref_kind);
1147   } else if (iid == vmIntrinsics::_invokeBasic) {
1148     has_receiver = true;
1149   } else if (iid == vmIntrinsics::_linkToNative) {
1150     member_arg_pos = method->size_of_parameters() - 1;  // trailing NativeEntryPoint argument
1151     member_reg = x9;  // known to be free at this point
1152   } else {
1153     fatal("unexpected intrinsic id %d", vmIntrinsics::as_int(iid));
1154   }
1155 
1156   if (member_reg != noreg) {
1157     // Load the member_arg into register, if necessary.
1158     SharedRuntime::check_member_name_argument_is_last_argument(method, sig_bt, regs);
1159     VMReg r = regs[member_arg_pos].first();
1160     if (r->is_stack()) {
1161       __ ld(member_reg, Address(sp, r->reg2stack() * VMRegImpl::stack_slot_size));
1162     } else {
1163       // no data motion is needed
1164       member_reg = r->as_Register();
1165     }
1166   }
1167 
1168   if (has_receiver) {
1169     // Make sure the receiver is loaded into a register.
1170     assert(method->size_of_parameters() > 0, "oob");
1171     assert(sig_bt[0] == T_OBJECT, "receiver argument must be an object");
1172     VMReg r = regs[0].first();
1173     assert(r->is_valid(), "bad receiver arg");
1174     if (r->is_stack()) {
1175       // Porting note:  This assumes that compiled calling conventions always
1176       // pass the receiver oop in a register.  If this is not true on some
1177       // platform, pick a temp and load the receiver from stack.
1178       fatal("receiver always in a register");
1179       receiver_reg = x12;  // known to be free at this point
1180       __ ld(receiver_reg, Address(sp, r->reg2stack() * VMRegImpl::stack_slot_size));
1181     } else {
1182       // no data motion is needed
1183       receiver_reg = r->as_Register();
1184     }
1185   }
1186 
1187   // Figure out which address we are really jumping to:
1188   MethodHandles::generate_method_handle_dispatch(masm, iid,
1189                                                  receiver_reg, member_reg, /*for_compiler_entry:*/ true);
1190 }
1191 
1192 // ---------------------------------------------------------------------------
1193 // Generate a native wrapper for a given method.  The method takes arguments
1194 // in the Java compiled code convention, marshals them to the native
1195 // convention (handlizes oops, etc), transitions to native, makes the call,
1196 // returns to java state (possibly blocking), unhandlizes any result and
1197 // returns.
1198 //
1199 // Critical native functions are a shorthand for the use of
1200 // GetPrimtiveArrayCritical and disallow the use of any other JNI
1201 // functions.  The wrapper is expected to unpack the arguments before
1202 // passing them to the callee and perform checks before and after the
1203 // native call to ensure that they GCLocker
1204 // lock_critical/unlock_critical semantics are followed.  Some other
1205 // parts of JNI setup are skipped like the tear down of the JNI handle
1206 // block and the check for pending exceptions it's impossible for them
1207 // to be thrown.
1208 //
1209 // They are roughly structured like this:
1210 //    if (GCLocker::needs_gc()) SharedRuntime::block_for_jni_critical()
1211 //    tranistion to thread_in_native
1212 //    unpack array arguments and call native entry point
1213 //    check for safepoint in progress
1214 //    check if any thread suspend flags are set
1215 //      call into JVM and possible unlock the JNI critical
1216 //      if a GC was suppressed while in the critical native.
1217 //    transition back to thread_in_Java
1218 //    return to caller
1219 //
1220 nmethod* SharedRuntime::generate_native_wrapper(MacroAssembler* masm,
1221                                                 const methodHandle& method,
1222                                                 int compile_id,
1223                                                 BasicType* in_sig_bt,
1224                                                 VMRegPair* in_regs,
1225                                                 BasicType ret_type) {
1226   if (method->is_continuation_native_intrinsic()) {
1227     int exception_offset = -1;
1228     OopMapSet* oop_maps = new OopMapSet();
1229     int frame_complete = -1;
1230     int stack_slots = -1;
1231     int interpreted_entry_offset = -1;
1232     int vep_offset = -1;
1233     if (method->is_continuation_enter_intrinsic()) {
1234       gen_continuation_enter(masm,
1235                              method,
1236                              in_sig_bt,
1237                              in_regs,
1238                              exception_offset,
1239                              oop_maps,
1240                              frame_complete,
1241                              stack_slots,
1242                              interpreted_entry_offset,
1243                              vep_offset);
1244     } else if (method->is_continuation_yield_intrinsic()) {
1245       gen_continuation_yield(masm,
1246                              method,
1247                              in_sig_bt,
1248                              in_regs,
1249                              oop_maps,
1250                              frame_complete,
1251                              stack_slots,
1252                              vep_offset);
1253     } else {
1254       guarantee(false, "Unknown Continuation native intrinsic");
1255     }
1256 
1257 #ifdef ASSERT
1258     if (method->is_continuation_enter_intrinsic()) {
1259       assert(interpreted_entry_offset != -1, "Must be set");
1260       assert(exception_offset != -1,         "Must be set");
1261     } else {
1262       assert(interpreted_entry_offset == -1, "Must be unset");
1263       assert(exception_offset == -1,         "Must be unset");
1264     }
1265     assert(frame_complete != -1,    "Must be set");
1266     assert(stack_slots != -1,       "Must be set");
1267     assert(vep_offset != -1,        "Must be set");
1268 #endif
1269 
1270     __ flush();
1271     nmethod* nm = nmethod::new_native_nmethod(method,
1272                                               compile_id,
1273                                               masm->code(),
1274                                               vep_offset,
1275                                               frame_complete,
1276                                               stack_slots,
1277                                               in_ByteSize(-1),
1278                                               in_ByteSize(-1),
1279                                               oop_maps,
1280                                               exception_offset);
1281     if (nm == nullptr) return nm;
1282     if (method->is_continuation_enter_intrinsic()) {
1283       ContinuationEntry::set_enter_code(nm, interpreted_entry_offset);
1284     } else if (method->is_continuation_yield_intrinsic()) {
1285       _cont_doYield_stub = nm;
1286     } else {
1287       guarantee(false, "Unknown Continuation native intrinsic");
1288     }
1289     return nm;
1290   }
1291 
1292   if (method->is_method_handle_intrinsic()) {
1293     vmIntrinsics::ID iid = method->intrinsic_id();
1294     intptr_t start = (intptr_t)__ pc();
1295     int vep_offset = ((intptr_t)__ pc()) - start;
1296 
1297     // First instruction must be a nop as it may need to be patched on deoptimisation
1298     {
1299       Assembler::IncompressibleScope scope(masm); // keep the nop as 4 bytes for patching.
1300       MacroAssembler::assert_alignment(__ pc());
1301       __ nop();  // 4 bytes
1302     }
1303     gen_special_dispatch(masm,
1304                          method,
1305                          in_sig_bt,
1306                          in_regs);
1307     int frame_complete = ((intptr_t)__ pc()) - start;  // not complete, period
1308     __ flush();
1309     int stack_slots = SharedRuntime::out_preserve_stack_slots();  // no out slots at all, actually
1310     return nmethod::new_native_nmethod(method,
1311                                        compile_id,
1312                                        masm->code(),
1313                                        vep_offset,
1314                                        frame_complete,
1315                                        stack_slots / VMRegImpl::slots_per_word,
1316                                        in_ByteSize(-1),
1317                                        in_ByteSize(-1),
1318                                        (OopMapSet*)nullptr);
1319   }
1320   address native_func = method->native_function();
1321   assert(native_func != nullptr, "must have function");
1322 
1323   // An OopMap for lock (and class if static)
1324   OopMapSet *oop_maps = new OopMapSet();
1325   assert_cond(oop_maps != nullptr);
1326   intptr_t start = (intptr_t)__ pc();
1327 
1328   // We have received a description of where all the java arg are located
1329   // on entry to the wrapper. We need to convert these args to where
1330   // the jni function will expect them. To figure out where they go
1331   // we convert the java signature to a C signature by inserting
1332   // the hidden arguments as arg[0] and possibly arg[1] (static method)
1333 
1334   const int total_in_args = method->size_of_parameters();
1335   int total_c_args = total_in_args + (method->is_static() ? 2 : 1);
1336 
1337   BasicType* out_sig_bt = NEW_RESOURCE_ARRAY(BasicType, total_c_args);
1338   VMRegPair* out_regs   = NEW_RESOURCE_ARRAY(VMRegPair, total_c_args);
1339 
1340   int argc = 0;
1341   out_sig_bt[argc++] = T_ADDRESS;
1342   if (method->is_static()) {
1343     out_sig_bt[argc++] = T_OBJECT;
1344   }
1345 
1346   for (int i = 0; i < total_in_args ; i++) {
1347     out_sig_bt[argc++] = in_sig_bt[i];
1348   }
1349 
1350   // Now figure out where the args must be stored and how much stack space
1351   // they require.
1352   int out_arg_slots = c_calling_convention(out_sig_bt, out_regs, total_c_args);
1353 
1354   // Compute framesize for the wrapper.  We need to handlize all oops in
1355   // incoming registers
1356 
1357   // Calculate the total number of stack slots we will need.
1358 
1359   // First count the abi requirement plus all of the outgoing args
1360   int stack_slots = SharedRuntime::out_preserve_stack_slots() + out_arg_slots;
1361 
1362   // Now the space for the inbound oop handle area
1363   int total_save_slots = 8 * VMRegImpl::slots_per_word;  // 8 arguments passed in registers
1364 
1365   int oop_handle_offset = stack_slots;
1366   stack_slots += total_save_slots;
1367 
1368   // Now any space we need for handlizing a klass if static method
1369 
1370   int klass_slot_offset = 0;
1371   int klass_offset = -1;
1372   int lock_slot_offset = 0;
1373   bool is_static = false;
1374 
1375   if (method->is_static()) {
1376     klass_slot_offset = stack_slots;
1377     stack_slots += VMRegImpl::slots_per_word;
1378     klass_offset = klass_slot_offset * VMRegImpl::stack_slot_size;
1379     is_static = true;
1380   }
1381 
1382   // Plus a lock if needed
1383 
1384   if (method->is_synchronized()) {
1385     lock_slot_offset = stack_slots;
1386     stack_slots += VMRegImpl::slots_per_word;
1387   }
1388 
1389   // Now a place (+2) to save return values or temp during shuffling
1390   // + 4 for return address (which we own) and saved fp
1391   stack_slots += 6;
1392 
1393   // Ok The space we have allocated will look like:
1394   //
1395   //
1396   // FP-> |                     |
1397   //      | 2 slots (ra)        |
1398   //      | 2 slots (fp)        |
1399   //      |---------------------|
1400   //      | 2 slots for moves   |
1401   //      |---------------------|
1402   //      | lock box (if sync)  |
1403   //      |---------------------| <- lock_slot_offset
1404   //      | klass (if static)   |
1405   //      |---------------------| <- klass_slot_offset
1406   //      | oopHandle area      |
1407   //      |---------------------| <- oop_handle_offset (8 java arg registers)
1408   //      | outbound memory     |
1409   //      | based arguments     |
1410   //      |                     |
1411   //      |---------------------|
1412   //      |                     |
1413   // SP-> | out_preserved_slots |
1414   //
1415   //
1416 
1417 
1418   // Now compute actual number of stack words we need rounding to make
1419   // stack properly aligned.
1420   stack_slots = align_up(stack_slots, StackAlignmentInSlots);
1421 
1422   int stack_size = stack_slots * VMRegImpl::stack_slot_size;
1423 
1424   // First thing make an ic check to see if we should even be here
1425 
1426   // We are free to use all registers as temps without saving them and
1427   // restoring them except fp. fp is the only callee save register
1428   // as far as the interpreter and the compiler(s) are concerned.
1429 
1430   const Register receiver = j_rarg0;
1431 
1432   __ verify_oop(receiver);
1433   assert_different_registers(receiver, t0, t1);
1434 
1435   __ ic_check();
1436 
1437   int vep_offset = ((intptr_t)__ pc()) - start;
1438 
1439   // If we have to make this method not-entrant we'll overwrite its
1440   // first instruction with a jump.
1441   {
1442     Assembler::IncompressibleScope scope(masm); // keep the nop as 4 bytes for patching.
1443     MacroAssembler::assert_alignment(__ pc());
1444     __ nop();  // 4 bytes
1445   }
1446 
1447   if (method->needs_clinit_barrier()) {
1448     assert(VM_Version::supports_fast_class_init_checks(), "sanity");
1449     Label L_skip_barrier;
1450     __ mov_metadata(t1, method->method_holder()); // InstanceKlass*
1451     __ clinit_barrier(t1, t0, &L_skip_barrier);
1452     __ far_jump(RuntimeAddress(SharedRuntime::get_handle_wrong_method_stub()));
1453 
1454     __ bind(L_skip_barrier);
1455   }
1456 
1457   // Generate stack overflow check
1458   __ bang_stack_with_offset(checked_cast<int>(StackOverflow::stack_shadow_zone_size()));
1459 
1460   // Generate a new frame for the wrapper.
1461   __ enter();
1462   // -2 because return address is already present and so is saved fp
1463   __ sub(sp, sp, stack_size - 2 * wordSize);
1464 
1465   BarrierSetAssembler* bs = BarrierSet::barrier_set()->barrier_set_assembler();
1466   assert_cond(bs != nullptr);
1467   bs->nmethod_entry_barrier(masm, nullptr /* slow_path */, nullptr /* continuation */, nullptr /* guard */);
1468 
1469   // Frame is now completed as far as size and linkage.
1470   int frame_complete = ((intptr_t)__ pc()) - start;
1471 
1472   // We use x18 as the oop handle for the receiver/klass
1473   // It is callee save so it survives the call to native
1474 
1475   const Register oop_handle_reg = x18;
1476 
1477   //
1478   // We immediately shuffle the arguments so that any vm call we have to
1479   // make from here on out (sync slow path, jvmti, etc.) we will have
1480   // captured the oops from our caller and have a valid oopMap for
1481   // them.
1482 
1483   // -----------------
1484   // The Grand Shuffle
1485 
1486   // The Java calling convention is either equal (linux) or denser (win64) than the
1487   // c calling convention. However the because of the jni_env argument the c calling
1488   // convention always has at least one more (and two for static) arguments than Java.
1489   // Therefore if we move the args from java -> c backwards then we will never have
1490   // a register->register conflict and we don't have to build a dependency graph
1491   // and figure out how to break any cycles.
1492   //
1493 
1494   // Record esp-based slot for receiver on stack for non-static methods
1495   int receiver_offset = -1;
1496 
1497   // This is a trick. We double the stack slots so we can claim
1498   // the oops in the caller's frame. Since we are sure to have
1499   // more args than the caller doubling is enough to make
1500   // sure we can capture all the incoming oop args from the
1501   // caller.
1502   //
1503   OopMap* map = new OopMap(stack_slots * 2, 0 /* arg_slots*/);
1504   assert_cond(map != nullptr);
1505 
1506   int float_args = 0;
1507   int int_args = 0;
1508 
1509 #ifdef ASSERT
1510   bool reg_destroyed[Register::number_of_registers];
1511   bool freg_destroyed[FloatRegister::number_of_registers];
1512   for ( int r = 0 ; r < Register::number_of_registers ; r++ ) {
1513     reg_destroyed[r] = false;
1514   }
1515   for ( int f = 0 ; f < FloatRegister::number_of_registers ; f++ ) {
1516     freg_destroyed[f] = false;
1517   }
1518 
1519 #endif /* ASSERT */
1520 
1521   // For JNI natives the incoming and outgoing registers are offset upwards.
1522   GrowableArray<int> arg_order(2 * total_in_args);
1523 
1524   for (int i = total_in_args - 1, c_arg = total_c_args - 1; i >= 0; i--, c_arg--) {
1525     arg_order.push(i);
1526     arg_order.push(c_arg);
1527   }
1528 
1529   for (int ai = 0; ai < arg_order.length(); ai += 2) {
1530     int i = arg_order.at(ai);
1531     int c_arg = arg_order.at(ai + 1);
1532     __ block_comment(err_msg("mv %d -> %d", i, c_arg));
1533     assert(c_arg != -1 && i != -1, "wrong order");
1534 #ifdef ASSERT
1535     if (in_regs[i].first()->is_Register()) {
1536       assert(!reg_destroyed[in_regs[i].first()->as_Register()->encoding()], "destroyed reg!");
1537     } else if (in_regs[i].first()->is_FloatRegister()) {
1538       assert(!freg_destroyed[in_regs[i].first()->as_FloatRegister()->encoding()], "destroyed reg!");
1539     }
1540     if (out_regs[c_arg].first()->is_Register()) {
1541       reg_destroyed[out_regs[c_arg].first()->as_Register()->encoding()] = true;
1542     } else if (out_regs[c_arg].first()->is_FloatRegister()) {
1543       freg_destroyed[out_regs[c_arg].first()->as_FloatRegister()->encoding()] = true;
1544     }
1545 #endif /* ASSERT */
1546     switch (in_sig_bt[i]) {
1547       case T_ARRAY:
1548       case T_OBJECT:
1549         __ object_move(map, oop_handle_offset, stack_slots, in_regs[i], out_regs[c_arg],
1550                        ((i == 0) && (!is_static)),
1551                        &receiver_offset);
1552         int_args++;
1553         break;
1554       case T_VOID:
1555         break;
1556 
1557       case T_FLOAT:
1558         __ float_move(in_regs[i], out_regs[c_arg]);
1559         float_args++;
1560         break;
1561 
1562       case T_DOUBLE:
1563         assert( i + 1 < total_in_args &&
1564                 in_sig_bt[i + 1] == T_VOID &&
1565                 out_sig_bt[c_arg + 1] == T_VOID, "bad arg list");
1566         __ double_move(in_regs[i], out_regs[c_arg]);
1567         float_args++;
1568         break;
1569 
1570       case T_LONG :
1571         __ long_move(in_regs[i], out_regs[c_arg]);
1572         int_args++;
1573         break;
1574 
1575       case T_ADDRESS:
1576         assert(false, "found T_ADDRESS in java args");
1577         break;
1578 
1579       default:
1580         __ move32_64(in_regs[i], out_regs[c_arg]);
1581         int_args++;
1582     }
1583   }
1584 
1585   // point c_arg at the first arg that is already loaded in case we
1586   // need to spill before we call out
1587   int c_arg = total_c_args - total_in_args;
1588 
1589   // Pre-load a static method's oop into c_rarg1.
1590   if (method->is_static()) {
1591 
1592     //  load oop into a register
1593     __ movoop(c_rarg1,
1594               JNIHandles::make_local(method->method_holder()->java_mirror()));
1595 
1596     // Now handlize the static class mirror it's known not-null.
1597     __ sd(c_rarg1, Address(sp, klass_offset));
1598     map->set_oop(VMRegImpl::stack2reg(klass_slot_offset));
1599 
1600     // Now get the handle
1601     __ la(c_rarg1, Address(sp, klass_offset));
1602     // and protect the arg if we must spill
1603     c_arg--;
1604   }
1605 
1606   // Change state to native (we save the return address in the thread, since it might not
1607   // be pushed on the stack when we do a stack traversal). It is enough that the pc()
1608   // points into the right code segment. It does not have to be the correct return pc.
1609   // We use the same pc/oopMap repeatedly when we call out.
1610 
1611   Label native_return;
1612   if (method->is_object_wait0()) {
1613     // For convenience we use the pc we want to resume to in case of preemption on Object.wait.
1614     __ set_last_Java_frame(sp, noreg, native_return, t0);
1615   } else {
1616     intptr_t the_pc = (intptr_t) __ pc();
1617     oop_maps->add_gc_map(the_pc - start, map);
1618 
1619     __ set_last_Java_frame(sp, noreg, __ pc(), t0);
1620   }
1621 
1622   Label dtrace_method_entry, dtrace_method_entry_done;
1623   if (DTraceMethodProbes) {
1624     __ j(dtrace_method_entry);
1625     __ bind(dtrace_method_entry_done);
1626   }
1627 
1628   // RedefineClasses() tracing support for obsolete method entry
1629   if (log_is_enabled(Trace, redefine, class, obsolete)) {
1630     // protect the args we've loaded
1631     save_args(masm, total_c_args, c_arg, out_regs);
1632     __ mov_metadata(c_rarg1, method());
1633     __ call_VM_leaf(
1634       CAST_FROM_FN_PTR(address, SharedRuntime::rc_trace_method_entry),
1635       xthread, c_rarg1);
1636     restore_args(masm, total_c_args, c_arg, out_regs);
1637   }
1638 
1639   // Lock a synchronized method
1640 
1641   // Register definitions used by locking and unlocking
1642 
1643   const Register swap_reg = x10;
1644   const Register obj_reg  = x9;  // Will contain the oop
1645   const Register lock_reg = x30;  // Address of compiler lock object (BasicLock)
1646   const Register old_hdr  = x30;  // value of old header at unlock time
1647   const Register lock_tmp = x31;  // Temporary used by fast_lock/unlock
1648   const Register tmp      = ra;
1649 
1650   Label slow_path_lock;
1651   Label lock_done;
1652 
1653   if (method->is_synchronized()) {
1654     // Get the handle (the 2nd argument)
1655     __ mv(oop_handle_reg, c_rarg1);
1656 
1657     // Get address of the box
1658 
1659     __ la(lock_reg, Address(sp, lock_slot_offset * VMRegImpl::stack_slot_size));
1660 
1661     // Load the oop from the handle
1662     __ ld(obj_reg, Address(oop_handle_reg, 0));
1663 
1664     __ fast_lock(lock_reg, obj_reg, swap_reg, tmp, lock_tmp, slow_path_lock);
1665 
1666     // Slow path will re-enter here
1667     __ bind(lock_done);
1668   }
1669 
1670 
1671   // Finally just about ready to make the JNI call
1672 
1673   // get JNIEnv* which is first argument to native
1674   __ la(c_rarg0, Address(xthread, in_bytes(JavaThread::jni_environment_offset())));
1675 
1676   // Now set thread in native
1677   __ la(t1, Address(xthread, JavaThread::thread_state_offset()));
1678   __ mv(t0, _thread_in_native);
1679   __ membar(MacroAssembler::LoadStore | MacroAssembler::StoreStore);
1680   __ sw(t0, Address(t1));
1681 
1682   // Clobbers t1
1683   __ rt_call(native_func);
1684 
1685   // Verify or restore cpu control state after JNI call
1686   __ restore_cpu_control_state_after_jni(t0);
1687 
1688   // Unpack native results.
1689   if (ret_type != T_OBJECT && ret_type != T_ARRAY) {
1690     __ cast_primitive_type(ret_type, x10);
1691   }
1692 
1693   Label safepoint_in_progress, safepoint_in_progress_done;
1694 
1695   // Switch thread to "native transition" state before reading the synchronization state.
1696   // This additional state is necessary because reading and testing the synchronization
1697   // state is not atomic w.r.t. GC, as this scenario demonstrates:
1698   //     Java thread A, in _thread_in_native state, loads _not_synchronized and is preempted.
1699   //     VM thread changes sync state to synchronizing and suspends threads for GC.
1700   //     Thread A is resumed to finish this native method, but doesn't block here since it
1701   //     didn't see any synchronization is progress, and escapes.
1702   __ mv(t0, _thread_in_native_trans);
1703 
1704   __ sw(t0, Address(xthread, JavaThread::thread_state_offset()));
1705 
1706   // Force this write out before the read below
1707   if (!UseSystemMemoryBarrier) {
1708     __ membar(MacroAssembler::AnyAny);
1709   }
1710 
1711   // check for safepoint operation in progress and/or pending suspend requests
1712   {
1713     __ safepoint_poll(safepoint_in_progress, true /* at_return */, false /* in_nmethod */);
1714     __ lwu(t0, Address(xthread, JavaThread::suspend_flags_offset()));
1715     __ bnez(t0, safepoint_in_progress);
1716     __ bind(safepoint_in_progress_done);
1717   }
1718 
1719   // change thread state
1720   __ la(t1, Address(xthread, JavaThread::thread_state_offset()));
1721   __ mv(t0, _thread_in_Java);
1722   __ membar(MacroAssembler::LoadStore | MacroAssembler::StoreStore);
1723   __ sw(t0, Address(t1));
1724 
1725   if (method->is_object_wait0()) {
1726     // Check preemption for Object.wait()
1727     __ ld(t1, Address(xthread, JavaThread::preempt_alternate_return_offset()));
1728     __ beqz(t1, native_return);
1729     __ sd(zr, Address(xthread, JavaThread::preempt_alternate_return_offset()));
1730     __ jr(t1);
1731     __ bind(native_return);
1732 
1733     intptr_t the_pc = (intptr_t) __ pc();
1734     oop_maps->add_gc_map(the_pc - start, map);
1735   }
1736 
1737   Label reguard;
1738   Label reguard_done;
1739   __ lbu(t0, Address(xthread, JavaThread::stack_guard_state_offset()));
1740   __ mv(t1, StackOverflow::stack_guard_yellow_reserved_disabled);
1741   __ beq(t0, t1, reguard);
1742   __ bind(reguard_done);
1743 
1744   // native result if any is live
1745 
1746   // Unlock
1747   Label unlock_done;
1748   Label slow_path_unlock;
1749   if (method->is_synchronized()) {
1750 
1751     // Get locked oop from the handle we passed to jni
1752     __ ld(obj_reg, Address(oop_handle_reg, 0));
1753 
1754     // Must save x10 if if it is live now because cmpxchg must use it
1755     if (ret_type != T_FLOAT && ret_type != T_DOUBLE && ret_type != T_VOID) {
1756       save_native_result(masm, ret_type, stack_slots);
1757     }
1758 
1759     __ fast_unlock(obj_reg, old_hdr, swap_reg, lock_tmp, slow_path_unlock);
1760 
1761     // slow path re-enters here
1762     __ bind(unlock_done);
1763     if (ret_type != T_FLOAT && ret_type != T_DOUBLE && ret_type != T_VOID) {
1764       restore_native_result(masm, ret_type, stack_slots);
1765     }
1766   }
1767 
1768   Label dtrace_method_exit, dtrace_method_exit_done;
1769   if (DTraceMethodProbes) {
1770     __ j(dtrace_method_exit);
1771     __ bind(dtrace_method_exit_done);
1772   }
1773 
1774   __ reset_last_Java_frame(false);
1775 
1776   // Unbox oop result, e.g. JNIHandles::resolve result.
1777   if (is_reference_type(ret_type)) {
1778     __ resolve_jobject(x10, x11, x12);
1779   }
1780 
1781   if (CheckJNICalls) {
1782     // clear_pending_jni_exception_check
1783     __ sd(zr, Address(xthread, JavaThread::pending_jni_exception_check_fn_offset()));
1784   }
1785 
1786   // reset handle block
1787   __ ld(x12, Address(xthread, JavaThread::active_handles_offset()));
1788   __ sd(zr, Address(x12, JNIHandleBlock::top_offset()));
1789 
1790   __ leave();
1791 
1792   #if INCLUDE_JFR
1793   // We need to do a poll test after unwind in case the sampler
1794   // managed to sample the native frame after returning to Java.
1795   Label L_return;
1796   __ ld(t0, Address(xthread, JavaThread::polling_word_offset()));
1797   address poll_test_pc = __ pc();
1798   __ relocate(relocInfo::poll_return_type);
1799   __ test_bit(t0, t0, log2i_exact(SafepointMechanism::poll_bit()));
1800   __ beqz(t0, L_return);
1801   assert(SharedRuntime::polling_page_return_handler_blob() != nullptr,
1802          "polling page return stub not created yet");
1803   address stub = SharedRuntime::polling_page_return_handler_blob()->entry_point();
1804   __ la(t0, InternalAddress(poll_test_pc));
1805   __ sd(t0, Address(xthread, JavaThread::saved_exception_pc_offset()));
1806   __ far_jump(RuntimeAddress(stub));
1807   __ bind(L_return);
1808 #endif // INCLUDE_JFR
1809 
1810   // Any exception pending?
1811   Label exception_pending;
1812   __ ld(t0, Address(xthread, in_bytes(Thread::pending_exception_offset())));
1813   __ bnez(t0, exception_pending);
1814 
1815   // We're done
1816   __ ret();
1817 
1818   // Unexpected paths are out of line and go here
1819 
1820   // forward the exception
1821   __ bind(exception_pending);
1822 
1823   // and forward the exception
1824   __ far_jump(RuntimeAddress(StubRoutines::forward_exception_entry()));
1825 
1826   // Slow path locking & unlocking
1827   if (method->is_synchronized()) {
1828 
1829     __ block_comment("Slow path lock {");
1830     __ bind(slow_path_lock);
1831 
1832     // has last_Java_frame setup. No exceptions so do vanilla call not call_VM
1833     // args are (oop obj, BasicLock* lock, JavaThread* thread)
1834 
1835     // protect the args we've loaded
1836     save_args(masm, total_c_args, c_arg, out_regs);
1837 
1838     __ mv(c_rarg0, obj_reg);
1839     __ mv(c_rarg1, lock_reg);
1840     __ mv(c_rarg2, xthread);
1841 
1842     // Not a leaf but we have last_Java_frame setup as we want.
1843     // We don't want to unmount in case of contention since that would complicate preserving
1844     // the arguments that had already been marshalled into the native convention. So we force
1845     // the freeze slow path to find this native wrapper frame (see recurse_freeze_native_frame())
1846     // and pin the vthread. Otherwise the fast path won't find it since we don't walk the stack.
1847     __ push_cont_fastpath();
1848     __ call_VM_leaf(CAST_FROM_FN_PTR(address, SharedRuntime::complete_monitor_locking_C), 3);
1849     __ pop_cont_fastpath();
1850     restore_args(masm, total_c_args, c_arg, out_regs);
1851 
1852 #ifdef ASSERT
1853     { Label L;
1854       __ ld(t0, Address(xthread, in_bytes(Thread::pending_exception_offset())));
1855       __ beqz(t0, L);
1856       __ stop("no pending exception allowed on exit from monitorenter");
1857       __ bind(L);
1858     }
1859 #endif
1860     __ j(lock_done);
1861 
1862     __ block_comment("} Slow path lock");
1863 
1864     __ block_comment("Slow path unlock {");
1865     __ bind(slow_path_unlock);
1866 
1867     if (ret_type == T_FLOAT || ret_type == T_DOUBLE) {
1868       save_native_result(masm, ret_type, stack_slots);
1869     }
1870 
1871     __ mv(c_rarg2, xthread);
1872     __ la(c_rarg1, Address(sp, lock_slot_offset * VMRegImpl::stack_slot_size));
1873     __ mv(c_rarg0, obj_reg);
1874 
1875     // Save pending exception around call to VM (which contains an EXCEPTION_MARK)
1876     // NOTE that obj_reg == x9 currently
1877     __ ld(x9, Address(xthread, in_bytes(Thread::pending_exception_offset())));
1878     __ sd(zr, Address(xthread, in_bytes(Thread::pending_exception_offset())));
1879 
1880     __ rt_call(CAST_FROM_FN_PTR(address, SharedRuntime::complete_monitor_unlocking_C));
1881 
1882 #ifdef ASSERT
1883     {
1884       Label L;
1885       __ ld(t0, Address(xthread, in_bytes(Thread::pending_exception_offset())));
1886       __ beqz(t0, L);
1887       __ stop("no pending exception allowed on exit complete_monitor_unlocking_C");
1888       __ bind(L);
1889     }
1890 #endif /* ASSERT */
1891 
1892     __ sd(x9, Address(xthread, in_bytes(Thread::pending_exception_offset())));
1893 
1894     if (ret_type == T_FLOAT || ret_type == T_DOUBLE) {
1895       restore_native_result(masm, ret_type, stack_slots);
1896     }
1897     __ j(unlock_done);
1898 
1899     __ block_comment("} Slow path unlock");
1900 
1901   } // synchronized
1902 
1903   // SLOW PATH Reguard the stack if needed
1904 
1905   __ bind(reguard);
1906   save_native_result(masm, ret_type, stack_slots);
1907   __ rt_call(CAST_FROM_FN_PTR(address, SharedRuntime::reguard_yellow_pages));
1908   restore_native_result(masm, ret_type, stack_slots);
1909   // and continue
1910   __ j(reguard_done);
1911 
1912   // SLOW PATH safepoint
1913   {
1914     __ block_comment("safepoint {");
1915     __ bind(safepoint_in_progress);
1916 
1917     // Don't use call_VM as it will see a possible pending exception and forward it
1918     // and never return here preventing us from clearing _last_native_pc down below.
1919     //
1920     save_native_result(masm, ret_type, stack_slots);
1921     __ mv(c_rarg0, xthread);
1922 #ifndef PRODUCT
1923     assert(frame::arg_reg_save_area_bytes == 0, "not expecting frame reg save area");
1924 #endif
1925     __ rt_call(CAST_FROM_FN_PTR(address, JavaThread::check_special_condition_for_native_trans));
1926 
1927     // Restore any method result value
1928     restore_native_result(masm, ret_type, stack_slots);
1929 
1930     __ j(safepoint_in_progress_done);
1931     __ block_comment("} safepoint");
1932   }
1933 
1934   // SLOW PATH dtrace support
1935   if (DTraceMethodProbes) {
1936     {
1937       __ block_comment("dtrace entry {");
1938       __ bind(dtrace_method_entry);
1939 
1940       // We have all of the arguments setup at this point. We must not touch any register
1941       // argument registers at this point (what if we save/restore them there are no oop?
1942 
1943       save_args(masm, total_c_args, c_arg, out_regs);
1944       __ mov_metadata(c_rarg1, method());
1945       __ call_VM_leaf(
1946         CAST_FROM_FN_PTR(address, SharedRuntime::dtrace_method_entry),
1947         xthread, c_rarg1);
1948       restore_args(masm, total_c_args, c_arg, out_regs);
1949       __ j(dtrace_method_entry_done);
1950       __ block_comment("} dtrace entry");
1951     }
1952 
1953     {
1954       __ block_comment("dtrace exit {");
1955       __ bind(dtrace_method_exit);
1956       save_native_result(masm, ret_type, stack_slots);
1957       __ mov_metadata(c_rarg1, method());
1958       __ call_VM_leaf(
1959            CAST_FROM_FN_PTR(address, SharedRuntime::dtrace_method_exit),
1960            xthread, c_rarg1);
1961       restore_native_result(masm, ret_type, stack_slots);
1962       __ j(dtrace_method_exit_done);
1963       __ block_comment("} dtrace exit");
1964     }
1965   }
1966 
1967   __ flush();
1968 
1969   nmethod *nm = nmethod::new_native_nmethod(method,
1970                                             compile_id,
1971                                             masm->code(),
1972                                             vep_offset,
1973                                             frame_complete,
1974                                             stack_slots / VMRegImpl::slots_per_word,
1975                                             (is_static ? in_ByteSize(klass_offset) : in_ByteSize(receiver_offset)),
1976                                             in_ByteSize(lock_slot_offset*VMRegImpl::stack_slot_size),
1977                                             oop_maps);
1978   assert(nm != nullptr, "create native nmethod fail!");
1979   return nm;
1980 }
1981 
1982 // this function returns the adjust size (in number of words) to a c2i adapter
1983 // activation for use during deoptimization
1984 int Deoptimization::last_frame_adjust(int callee_parameters, int callee_locals) {
1985   assert(callee_locals >= callee_parameters,
1986          "test and remove; got more parms than locals");
1987   if (callee_locals < callee_parameters) {
1988     return 0;                   // No adjustment for negative locals
1989   }
1990   int diff = (callee_locals - callee_parameters) * Interpreter::stackElementWords;
1991   // diff is counted in stack words
1992   return align_up(diff, 2);
1993 }
1994 
1995 //------------------------------generate_deopt_blob----------------------------
1996 void SharedRuntime::generate_deopt_blob() {
1997   // Allocate space for the code
1998   ResourceMark rm;
1999   // Setup code generation tools
2000   int pad = 0;
2001 #if INCLUDE_JVMCI
2002   if (EnableJVMCI) {
2003     pad += 512; // Increase the buffer size when compiling for JVMCI
2004   }
2005 #endif
2006   const char* name = SharedRuntime::stub_name(StubId::shared_deopt_id);
2007   CodeBuffer buffer(name, 2048 + pad, 1024);
2008   MacroAssembler* masm = new MacroAssembler(&buffer);
2009   int frame_size_in_words = -1;
2010   OopMap* map = nullptr;
2011   OopMapSet *oop_maps = new OopMapSet();
2012   assert_cond(masm != nullptr && oop_maps != nullptr);
2013   RegisterSaver reg_saver(COMPILER2_OR_JVMCI != 0);
2014 
2015   // -------------
2016   // This code enters when returning to a de-optimized nmethod.  A return
2017   // address has been pushed on the stack, and return values are in
2018   // registers.
2019   // If we are doing a normal deopt then we were called from the patched
2020   // nmethod from the point we returned to the nmethod. So the return
2021   // address on the stack is wrong by NativeCall::instruction_size
2022   // We will adjust the value so it looks like we have the original return
2023   // address on the stack (like when we eagerly deoptimized).
2024   // In the case of an exception pending when deoptimizing, we enter
2025   // with a return address on the stack that points after the call we patched
2026   // into the exception handler. We have the following register state from,
2027   // e.g., the forward exception stub (see stubGenerator_riscv.cpp).
2028   //    x10: exception oop
2029   //    x9: exception handler
2030   //    x13: throwing pc
2031   // So in this case we simply jam x13 into the useless return address and
2032   // the stack looks just like we want.
2033   //
2034   // At this point we need to de-opt.  We save the argument return
2035   // registers.  We call the first C routine, fetch_unroll_info().  This
2036   // routine captures the return values and returns a structure which
2037   // describes the current frame size and the sizes of all replacement frames.
2038   // The current frame is compiled code and may contain many inlined
2039   // functions, each with their own JVM state.  We pop the current frame, then
2040   // push all the new frames.  Then we call the C routine unpack_frames() to
2041   // populate these frames.  Finally unpack_frames() returns us the new target
2042   // address.  Notice that callee-save registers are BLOWN here; they have
2043   // already been captured in the vframeArray at the time the return PC was
2044   // patched.
2045   address start = __ pc();
2046   Label cont;
2047 
2048   // Prolog for non exception case!
2049 
2050   // Save everything in sight.
2051   map = reg_saver.save_live_registers(masm, 0, &frame_size_in_words);
2052 
2053   // Normal deoptimization.  Save exec mode for unpack_frames.
2054   __ mv(xcpool, Deoptimization::Unpack_deopt); // callee-saved
2055   __ j(cont);
2056 
2057   int reexecute_offset = __ pc() - start;
2058 #if INCLUDE_JVMCI && !defined(COMPILER1)
2059   if (UseJVMCICompiler) {
2060     // JVMCI does not use this kind of deoptimization
2061     __ should_not_reach_here();
2062   }
2063 #endif
2064 
2065   // Reexecute case
2066   // return address is the pc describes what bci to do re-execute at
2067 
2068   // No need to update map as each call to save_live_registers will produce identical oopmap
2069   (void) reg_saver.save_live_registers(masm, 0, &frame_size_in_words);
2070 
2071   __ mv(xcpool, Deoptimization::Unpack_reexecute); // callee-saved
2072   __ j(cont);
2073 
2074 #if INCLUDE_JVMCI
2075   Label after_fetch_unroll_info_call;
2076   int implicit_exception_uncommon_trap_offset = 0;
2077   int uncommon_trap_offset = 0;
2078 
2079   if (EnableJVMCI) {
2080     implicit_exception_uncommon_trap_offset = __ pc() - start;
2081 
2082     __ ld(ra, Address(xthread, in_bytes(JavaThread::jvmci_implicit_exception_pc_offset())));
2083     __ sd(zr, Address(xthread, in_bytes(JavaThread::jvmci_implicit_exception_pc_offset())));
2084 
2085     uncommon_trap_offset = __ pc() - start;
2086 
2087     // Save everything in sight.
2088     reg_saver.save_live_registers(masm, 0, &frame_size_in_words);
2089     // fetch_unroll_info needs to call last_java_frame()
2090     Label retaddr;
2091     __ set_last_Java_frame(sp, noreg, retaddr, t0);
2092 
2093     __ lw(c_rarg1, Address(xthread, in_bytes(JavaThread::pending_deoptimization_offset())));
2094     __ mv(t0, -1);
2095     __ sw(t0, Address(xthread, in_bytes(JavaThread::pending_deoptimization_offset())));
2096 
2097     __ mv(xcpool, Deoptimization::Unpack_reexecute);
2098     __ mv(c_rarg0, xthread);
2099     __ orrw(c_rarg2, zr, xcpool); // exec mode
2100     __ rt_call(CAST_FROM_FN_PTR(address, Deoptimization::uncommon_trap));
2101     __ bind(retaddr);
2102     oop_maps->add_gc_map( __ pc()-start, map->deep_copy());
2103 
2104     __ reset_last_Java_frame(false);
2105 
2106     __ j(after_fetch_unroll_info_call);
2107   } // EnableJVMCI
2108 #endif // INCLUDE_JVMCI
2109 
2110   int exception_offset = __ pc() - start;
2111 
2112   // Prolog for exception case
2113 
2114   // all registers are dead at this entry point, except for x10, and
2115   // x13 which contain the exception oop and exception pc
2116   // respectively.  Set them in TLS and fall thru to the
2117   // unpack_with_exception_in_tls entry point.
2118 
2119   __ sd(x13, Address(xthread, JavaThread::exception_pc_offset()));
2120   __ sd(x10, Address(xthread, JavaThread::exception_oop_offset()));
2121 
2122   int exception_in_tls_offset = __ pc() - start;
2123 
2124   // new implementation because exception oop is now passed in JavaThread
2125 
2126   // Prolog for exception case
2127   // All registers must be preserved because they might be used by LinearScan
2128   // Exceptiop oop and throwing PC are passed in JavaThread
2129   // tos: stack at point of call to method that threw the exception (i.e. only
2130   // args are on the stack, no return address)
2131 
2132   // The return address pushed by save_live_registers will be patched
2133   // later with the throwing pc. The correct value is not available
2134   // now because loading it from memory would destroy registers.
2135 
2136   // NB: The SP at this point must be the SP of the method that is
2137   // being deoptimized.  Deoptimization assumes that the frame created
2138   // here by save_live_registers is immediately below the method's SP.
2139   // This is a somewhat fragile mechanism.
2140 
2141   // Save everything in sight.
2142   map = reg_saver.save_live_registers(masm, 0, &frame_size_in_words);
2143 
2144   // Now it is safe to overwrite any register
2145 
2146   // Deopt during an exception.  Save exec mode for unpack_frames.
2147   __ mv(xcpool, Deoptimization::Unpack_exception); // callee-saved
2148 
2149   // load throwing pc from JavaThread and patch it as the return address
2150   // of the current frame. Then clear the field in JavaThread
2151 
2152   __ ld(x13, Address(xthread, JavaThread::exception_pc_offset()));
2153   __ sd(x13, Address(fp, frame::return_addr_offset * wordSize));
2154   __ sd(zr, Address(xthread, JavaThread::exception_pc_offset()));
2155 
2156 #ifdef ASSERT
2157   // verify that there is really an exception oop in JavaThread
2158   __ ld(x10, Address(xthread, JavaThread::exception_oop_offset()));
2159   __ verify_oop(x10);
2160 
2161   // verify that there is no pending exception
2162   Label no_pending_exception;
2163   __ ld(t0, Address(xthread, Thread::pending_exception_offset()));
2164   __ beqz(t0, no_pending_exception);
2165   __ stop("must not have pending exception here");
2166   __ bind(no_pending_exception);
2167 #endif
2168 
2169   __ bind(cont);
2170 
2171   // Call C code.  Need thread and this frame, but NOT official VM entry
2172   // crud.  We cannot block on this call, no GC can happen.
2173   //
2174   // UnrollBlock* fetch_unroll_info(JavaThread* thread)
2175 
2176   // fetch_unroll_info needs to call last_java_frame().
2177 
2178   Label retaddr;
2179   __ set_last_Java_frame(sp, noreg, retaddr, t0);
2180 #ifdef ASSERT
2181   {
2182     Label L;
2183     __ ld(t0, Address(xthread,
2184                               JavaThread::last_Java_fp_offset()));
2185     __ beqz(t0, L);
2186     __ stop("SharedRuntime::generate_deopt_blob: last_Java_fp not cleared");
2187     __ bind(L);
2188   }
2189 #endif // ASSERT
2190   __ mv(c_rarg0, xthread);
2191   __ mv(c_rarg1, xcpool);
2192   __ rt_call(CAST_FROM_FN_PTR(address, Deoptimization::fetch_unroll_info));
2193   __ bind(retaddr);
2194 
2195   // Need to have an oopmap that tells fetch_unroll_info where to
2196   // find any register it might need.
2197   oop_maps->add_gc_map(__ pc() - start, map);
2198 
2199   __ reset_last_Java_frame(false);
2200 
2201 #if INCLUDE_JVMCI
2202   if (EnableJVMCI) {
2203     __ bind(after_fetch_unroll_info_call);
2204   }
2205 #endif
2206 
2207   // Load UnrollBlock* into x15
2208   __ mv(x15, x10);
2209 
2210   __ lwu(xcpool, Address(x15, Deoptimization::UnrollBlock::unpack_kind_offset()));
2211   Label noException;
2212   __ mv(t0, Deoptimization::Unpack_exception);
2213   __ bne(xcpool, t0, noException); // Was exception pending?
2214   __ ld(x10, Address(xthread, JavaThread::exception_oop_offset()));
2215   __ ld(x13, Address(xthread, JavaThread::exception_pc_offset()));
2216   __ sd(zr, Address(xthread, JavaThread::exception_oop_offset()));
2217   __ sd(zr, Address(xthread, JavaThread::exception_pc_offset()));
2218 
2219   __ verify_oop(x10);
2220 
2221   // Overwrite the result registers with the exception results.
2222   __ sd(x10, Address(sp, reg_saver.reg_offset_in_bytes(x10)));
2223 
2224   __ bind(noException);
2225 
2226   // Only register save data is on the stack.
2227   // Now restore the result registers.  Everything else is either dead
2228   // or captured in the vframeArray.
2229 
2230   // Restore fp result register
2231   __ fld(f10, Address(sp, reg_saver.freg_offset_in_bytes(f10)));
2232   // Restore integer result register
2233   __ ld(x10, Address(sp, reg_saver.reg_offset_in_bytes(x10)));
2234 
2235   // Pop all of the register save area off the stack
2236   __ add(sp, sp, frame_size_in_words * wordSize);
2237 
2238   // All of the register save area has been popped of the stack. Only the
2239   // return address remains.
2240 
2241   // Pop all the frames we must move/replace.
2242   //
2243   // Frame picture (youngest to oldest)
2244   // 1: self-frame (no frame link)
2245   // 2: deopting frame  (no frame link)
2246   // 3: caller of deopting frame (could be compiled/interpreted).
2247   //
2248   // Note: by leaving the return address of self-frame on the stack
2249   // and using the size of frame 2 to adjust the stack
2250   // when we are done the return to frame 3 will still be on the stack.
2251 
2252   // Pop deoptimized frame
2253   __ lwu(x12, Address(x15, Deoptimization::UnrollBlock::size_of_deoptimized_frame_offset()));
2254   __ subi(x12, x12, 2 * wordSize);
2255   __ add(sp, sp, x12);
2256   __ ld(fp, Address(sp, 0));
2257   __ ld(ra, Address(sp, wordSize));
2258   __ addi(sp, sp, 2 * wordSize);
2259   // RA should now be the return address to the caller (3)
2260 
2261 #ifdef ASSERT
2262   // Compilers generate code that bang the stack by as much as the
2263   // interpreter would need. So this stack banging should never
2264   // trigger a fault. Verify that it does not on non product builds.
2265   __ lwu(x9, Address(x15, Deoptimization::UnrollBlock::total_frame_sizes_offset()));
2266   __ bang_stack_size(x9, x12);
2267 #endif
2268   // Load address of array of frame pcs into x12
2269   __ ld(x12, Address(x15, Deoptimization::UnrollBlock::frame_pcs_offset()));
2270 
2271   // Load address of array of frame sizes into x14
2272   __ ld(x14, Address(x15, Deoptimization::UnrollBlock::frame_sizes_offset()));
2273 
2274   // Load counter into x13
2275   __ lwu(x13, Address(x15, Deoptimization::UnrollBlock::number_of_frames_offset()));
2276 
2277   // Now adjust the caller's stack to make up for the extra locals
2278   // but record the original sp so that we can save it in the skeletal interpreter
2279   // frame and the stack walking of interpreter_sender will get the unextended sp
2280   // value and not the "real" sp value.
2281 
2282   const Register sender_sp = x16;
2283 
2284   __ mv(sender_sp, sp);
2285   __ lwu(x9, Address(x15,
2286                      Deoptimization::UnrollBlock::
2287                      caller_adjustment_offset()));
2288   __ sub(sp, sp, x9);
2289 
2290   // Push interpreter frames in a loop
2291   __ mv(t0, 0xDEADDEAD);               // Make a recognizable pattern
2292   __ mv(t1, t0);
2293   Label loop;
2294   __ bind(loop);
2295   __ ld(x9, Address(x14, 0));          // Load frame size
2296   __ addi(x14, x14, wordSize);
2297   __ subi(x9, x9, 2 * wordSize);       // We'll push pc and fp by hand
2298   __ ld(ra, Address(x12, 0));          // Load pc
2299   __ addi(x12, x12, wordSize);
2300   __ enter();                          // Save old & set new fp
2301   __ sub(sp, sp, x9);                  // Prolog
2302   // This value is corrected by layout_activation_impl
2303   __ sd(zr, Address(fp, frame::interpreter_frame_last_sp_offset * wordSize));
2304   __ sd(sender_sp, Address(fp, frame::interpreter_frame_sender_sp_offset * wordSize)); // Make it walkable
2305   __ mv(sender_sp, sp);                // Pass sender_sp to next frame
2306   __ subi(x13, x13, 1);                // Decrement counter
2307   __ bnez(x13, loop);
2308 
2309     // Re-push self-frame
2310   __ ld(ra, Address(x12));
2311   __ enter();
2312 
2313   // Allocate a full sized register save area.  We subtract 2 because
2314   // enter() just pushed 2 words
2315   __ sub(sp, sp, (frame_size_in_words - 2) * wordSize);
2316 
2317   // Restore frame locals after moving the frame
2318   __ fsd(f10, Address(sp, reg_saver.freg_offset_in_bytes(f10)));
2319   __ sd(x10, Address(sp, reg_saver.reg_offset_in_bytes(x10)));
2320 
2321   // Call C code.  Need thread but NOT official VM entry
2322   // crud.  We cannot block on this call, no GC can happen.  Call should
2323   // restore return values to their stack-slots with the new SP.
2324   //
2325   // void Deoptimization::unpack_frames(JavaThread* thread, int exec_mode)
2326 
2327   // Use fp because the frames look interpreted now
2328   // Don't need the precise return PC here, just precise enough to point into this code blob.
2329   address the_pc = __ pc();
2330   __ set_last_Java_frame(sp, fp, the_pc, t0);
2331 
2332   __ mv(c_rarg0, xthread);
2333   __ mv(c_rarg1, xcpool); // second arg: exec_mode
2334   __ rt_call(CAST_FROM_FN_PTR(address, Deoptimization::unpack_frames));
2335 
2336   // Set an oopmap for the call site
2337   // Use the same PC we used for the last java frame
2338   oop_maps->add_gc_map(the_pc - start,
2339                        new OopMap(frame_size_in_words, 0));
2340 
2341   // Clear fp AND pc
2342   __ reset_last_Java_frame(true);
2343 
2344   // Collect return values
2345   __ fld(f10, Address(sp, reg_saver.freg_offset_in_bytes(f10)));
2346   __ ld(x10, Address(sp, reg_saver.reg_offset_in_bytes(x10)));
2347 
2348   // Pop self-frame.
2349   __ leave();                           // Epilog
2350 
2351   // Jump to interpreter
2352   __ ret();
2353 
2354   // Make sure all code is generated
2355   masm->flush();
2356 
2357   _deopt_blob = DeoptimizationBlob::create(&buffer, oop_maps, 0, exception_offset, reexecute_offset, frame_size_in_words);
2358   assert(_deopt_blob != nullptr, "create deoptimization blob fail!");
2359   _deopt_blob->set_unpack_with_exception_in_tls_offset(exception_in_tls_offset);
2360 #if INCLUDE_JVMCI
2361   if (EnableJVMCI) {
2362     _deopt_blob->set_uncommon_trap_offset(uncommon_trap_offset);
2363     _deopt_blob->set_implicit_exception_uncommon_trap_offset(implicit_exception_uncommon_trap_offset);
2364   }
2365 #endif
2366 }
2367 
2368 // Number of stack slots between incoming argument block and the start of
2369 // a new frame. The PROLOG must add this many slots to the stack. The
2370 // EPILOG must remove this many slots.
2371 // RISCV needs two words for RA (return address) and FP (frame pointer).
2372 uint SharedRuntime::in_preserve_stack_slots() {
2373   return 2 * VMRegImpl::slots_per_word + (VerifyStackAtCalls ? 0 : 2) ;
2374 }
2375 
2376 uint SharedRuntime::out_preserve_stack_slots() {
2377   return 0;
2378 }
2379 
2380 VMReg SharedRuntime::thread_register() {
2381   return xthread->as_VMReg();
2382 }
2383 
2384 //------------------------------generate_handler_blob------
2385 //
2386 // Generate a special Compile2Runtime blob that saves all registers,
2387 // and setup oopmap.
2388 //
2389 SafepointBlob* SharedRuntime::generate_handler_blob(StubId id, address call_ptr) {
2390   assert(is_polling_page_id(id), "expected a polling page stub id");
2391 
2392   ResourceMark rm;
2393   OopMapSet *oop_maps = new OopMapSet();
2394   assert_cond(oop_maps != nullptr);
2395   OopMap* map = nullptr;
2396 
2397   // Allocate space for the code.  Setup code generation tools.
2398   const char* name = SharedRuntime::stub_name(id);
2399   CodeBuffer buffer(name, 2048, 1024);
2400   MacroAssembler* masm = new MacroAssembler(&buffer);
2401   assert_cond(masm != nullptr);
2402 
2403   address start   = __ pc();
2404   address call_pc = nullptr;
2405   int frame_size_in_words = -1;
2406   bool cause_return = (id == StubId::shared_polling_page_return_handler_id);
2407   RegisterSaver reg_saver(id == StubId::shared_polling_page_vectors_safepoint_handler_id /* save_vectors */);
2408 
2409   // Save Integer and Float registers.
2410   map = reg_saver.save_live_registers(masm, 0, &frame_size_in_words);
2411 
2412   // The following is basically a call_VM.  However, we need the precise
2413   // address of the call in order to generate an oopmap. Hence, we do all the
2414   // work ourselves.
2415 
2416   Label retaddr;
2417   __ set_last_Java_frame(sp, noreg, retaddr, t0);
2418 
2419   // The return address must always be correct so that frame constructor never
2420   // sees an invalid pc.
2421 
2422   if (!cause_return) {
2423     // overwrite the return address pushed by save_live_registers
2424     // Additionally, x18 is a callee-saved register so we can look at
2425     // it later to determine if someone changed the return address for
2426     // us!
2427     __ ld(x18, Address(xthread, JavaThread::saved_exception_pc_offset()));
2428     __ sd(x18, Address(fp, frame::return_addr_offset * wordSize));
2429   }
2430 
2431   // Do the call
2432   __ mv(c_rarg0, xthread);
2433   __ rt_call(call_ptr);
2434   __ bind(retaddr);
2435 
2436   // Set an oopmap for the call site.  This oopmap will map all
2437   // oop-registers and debug-info registers as callee-saved.  This
2438   // will allow deoptimization at this safepoint to find all possible
2439   // debug-info recordings, as well as let GC find all oops.
2440 
2441   oop_maps->add_gc_map( __ pc() - start, map);
2442 
2443   Label noException;
2444 
2445   __ reset_last_Java_frame(false);
2446 
2447   __ membar(MacroAssembler::LoadLoad | MacroAssembler::LoadStore);
2448 
2449   __ ld(t0, Address(xthread, Thread::pending_exception_offset()));
2450   __ beqz(t0, noException);
2451 
2452   // Exception pending
2453 
2454   reg_saver.restore_live_registers(masm);
2455 
2456   __ far_jump(RuntimeAddress(StubRoutines::forward_exception_entry()));
2457 
2458   // No exception case
2459   __ bind(noException);
2460 
2461   Label no_adjust, bail;
2462   if (!cause_return) {
2463     // If our stashed return pc was modified by the runtime we avoid touching it
2464     __ ld(t0, Address(fp, frame::return_addr_offset * wordSize));
2465     __ bne(x18, t0, no_adjust);
2466 
2467 #ifdef ASSERT
2468     // Verify the correct encoding of the poll we're about to skip.
2469     // See NativeInstruction::is_lwu_to_zr()
2470     __ lwu(t0, Address(x18));
2471     __ andi(t1, t0, 0b1111111);
2472     __ mv(t2, 0b0000011);
2473     __ bne(t1, t2, bail); // 0-6:0b0000011
2474     __ srli(t1, t0, 7);
2475     __ andi(t1, t1, 0b11111);
2476     __ bnez(t1, bail);    // 7-11:0b00000
2477     __ srli(t1, t0, 12);
2478     __ andi(t1, t1, 0b111);
2479     __ mv(t2, 0b110);
2480     __ bne(t1, t2, bail); // 12-14:0b110
2481 #endif
2482 
2483     // Adjust return pc forward to step over the safepoint poll instruction
2484     __ addi(x18, x18, NativeInstruction::instruction_size);
2485     __ sd(x18, Address(fp, frame::return_addr_offset * wordSize));
2486   }
2487 
2488   __ bind(no_adjust);
2489   // Normal exit, restore registers and exit.
2490 
2491   reg_saver.restore_live_registers(masm);
2492   __ ret();
2493 
2494 #ifdef ASSERT
2495   __ bind(bail);
2496   __ stop("Attempting to adjust pc to skip safepoint poll but the return point is not what we expected");
2497 #endif
2498 
2499   // Make sure all code is generated
2500   masm->flush();
2501 
2502   // Fill-out other meta info
2503   return SafepointBlob::create(&buffer, oop_maps, frame_size_in_words);
2504 }
2505 
2506 //
2507 // generate_resolve_blob - call resolution (static/virtual/opt-virtual/ic-miss
2508 //
2509 // Generate a stub that calls into vm to find out the proper destination
2510 // of a java call. All the argument registers are live at this point
2511 // but since this is generic code we don't know what they are and the caller
2512 // must do any gc of the args.
2513 //
2514 RuntimeStub* SharedRuntime::generate_resolve_blob(StubId id, address destination) {
2515   assert(StubRoutines::forward_exception_entry() != nullptr, "must be generated before");
2516   assert(is_resolve_id(id), "expected a resolve stub id");
2517 
2518   // allocate space for the code
2519   ResourceMark rm;
2520 
2521   const char* name = SharedRuntime::stub_name(id);
2522   CodeBuffer buffer(name, 1000, 512);
2523   MacroAssembler* masm = new MacroAssembler(&buffer);
2524   assert_cond(masm != nullptr);
2525 
2526   int frame_size_in_words = -1;
2527   RegisterSaver reg_saver(false /* save_vectors */);
2528 
2529   OopMapSet *oop_maps = new OopMapSet();
2530   assert_cond(oop_maps != nullptr);
2531   OopMap* map = nullptr;
2532 
2533   int start = __ offset();
2534 
2535   map = reg_saver.save_live_registers(masm, 0, &frame_size_in_words);
2536 
2537   int frame_complete = __ offset();
2538 
2539   {
2540     Label retaddr;
2541     __ set_last_Java_frame(sp, noreg, retaddr, t0);
2542 
2543     __ mv(c_rarg0, xthread);
2544     __ rt_call(destination);
2545     __ bind(retaddr);
2546   }
2547 
2548   // Set an oopmap for the call site.
2549   // We need this not only for callee-saved registers, but also for volatile
2550   // registers that the compiler might be keeping live across a safepoint.
2551 
2552   oop_maps->add_gc_map( __ offset() - start, map);
2553 
2554   // x10 contains the address we are going to jump to assuming no exception got installed
2555 
2556   // clear last_Java_sp
2557   __ reset_last_Java_frame(false);
2558   // check for pending exceptions
2559   Label pending;
2560   __ ld(t1, Address(xthread, Thread::pending_exception_offset()));
2561   __ bnez(t1, pending);
2562 
2563   // get the returned Method*
2564   __ get_vm_result_metadata(xmethod, xthread);
2565   __ sd(xmethod, Address(sp, reg_saver.reg_offset_in_bytes(xmethod)));
2566 
2567   // x10 is where we want to jump, overwrite t1 which is saved and temporary
2568   __ sd(x10, Address(sp, reg_saver.reg_offset_in_bytes(t1)));
2569   reg_saver.restore_live_registers(masm);
2570 
2571   // We are back to the original state on entry and ready to go.
2572   __ jr(t1);
2573 
2574   // Pending exception after the safepoint
2575 
2576   __ bind(pending);
2577 
2578   reg_saver.restore_live_registers(masm);
2579 
2580   // exception pending => remove activation and forward to exception handler
2581 
2582   __ sd(zr, Address(xthread, JavaThread::vm_result_oop_offset()));
2583 
2584   __ ld(x10, Address(xthread, Thread::pending_exception_offset()));
2585   __ far_jump(RuntimeAddress(StubRoutines::forward_exception_entry()));
2586 
2587   // -------------
2588   // make sure all code is generated
2589   masm->flush();
2590 
2591   // return the  blob
2592   return RuntimeStub::new_runtime_stub(name, &buffer, frame_complete, frame_size_in_words, oop_maps, true);
2593 }
2594 
2595 // Continuation point for throwing of implicit exceptions that are
2596 // not handled in the current activation. Fabricates an exception
2597 // oop and initiates normal exception dispatching in this
2598 // frame. Since we need to preserve callee-saved values (currently
2599 // only for C2, but done for C1 as well) we need a callee-saved oop
2600 // map and therefore have to make these stubs into RuntimeStubs
2601 // rather than BufferBlobs.  If the compiler needs all registers to
2602 // be preserved between the fault point and the exception handler
2603 // then it must assume responsibility for that in
2604 // AbstractCompiler::continuation_for_implicit_null_exception or
2605 // continuation_for_implicit_division_by_zero_exception. All other
2606 // implicit exceptions (e.g., NullPointerException or
2607 // AbstractMethodError on entry) are either at call sites or
2608 // otherwise assume that stack unwinding will be initiated, so
2609 // caller saved registers were assumed volatile in the compiler.
2610 
2611 RuntimeStub* SharedRuntime::generate_throw_exception(StubId id, address runtime_entry) {
2612   assert(is_throw_id(id), "expected a throw stub id");
2613 
2614   const char* name = SharedRuntime::stub_name(id);
2615 
2616   // Information about frame layout at time of blocking runtime call.
2617   // Note that we only have to preserve callee-saved registers since
2618   // the compilers are responsible for supplying a continuation point
2619   // if they expect all registers to be preserved.
2620   // n.b. riscv asserts that frame::arg_reg_save_area_bytes == 0
2621   assert_cond(runtime_entry != nullptr);
2622   enum layout {
2623     fp_off = 0,
2624     fp_off2,
2625     return_off,
2626     return_off2,
2627     framesize // inclusive of return address
2628   };
2629 
2630   const int insts_size = 1024;
2631   const int locs_size  = 64;
2632 
2633   ResourceMark rm;
2634   const char* timer_msg = "SharedRuntime generate_throw_exception";
2635   TraceTime timer(timer_msg, TRACETIME_LOG(Info, startuptime));
2636 
2637   CodeBuffer code(name, insts_size, locs_size);
2638   OopMapSet* oop_maps  = new OopMapSet();
2639   MacroAssembler* masm = new MacroAssembler(&code);
2640   assert_cond(oop_maps != nullptr && masm != nullptr);
2641 
2642   address start = __ pc();
2643 
2644   // This is an inlined and slightly modified version of call_VM
2645   // which has the ability to fetch the return PC out of
2646   // thread-local storage and also sets up last_Java_sp slightly
2647   // differently than the real call_VM
2648 
2649   __ enter(); // Save FP and RA before call
2650 
2651   assert(is_even(framesize / 2), "sp not 16-byte aligned");
2652 
2653   // ra and fp are already in place
2654   __ subi(sp, fp, (unsigned)framesize << LogBytesPerInt); // prolog
2655 
2656   int frame_complete = __ pc() - start;
2657 
2658   // Set up last_Java_sp and last_Java_fp
2659   address the_pc = __ pc();
2660   __ set_last_Java_frame(sp, fp, the_pc, t0);
2661 
2662   // Call runtime
2663   __ mv(c_rarg0, xthread);
2664   BLOCK_COMMENT("call runtime_entry");
2665   __ rt_call(runtime_entry);
2666 
2667   // Generate oop map
2668   OopMap* map = new OopMap(framesize, 0);
2669   assert_cond(map != nullptr);
2670 
2671   oop_maps->add_gc_map(the_pc - start, map);
2672 
2673   __ reset_last_Java_frame(true);
2674 
2675   __ leave();
2676 
2677   // check for pending exceptions
2678 #ifdef ASSERT
2679   Label L;
2680   __ ld(t0, Address(xthread, Thread::pending_exception_offset()));
2681   __ bnez(t0, L);
2682   __ should_not_reach_here();
2683   __ bind(L);
2684 #endif // ASSERT
2685   __ far_jump(RuntimeAddress(StubRoutines::forward_exception_entry()));
2686 
2687   // codeBlob framesize is in words (not VMRegImpl::slot_size)
2688   RuntimeStub* stub =
2689     RuntimeStub::new_runtime_stub(name,
2690                                   &code,
2691                                   frame_complete,
2692                                   (framesize >> (LogBytesPerWord - LogBytesPerInt)),
2693                                   oop_maps, false);
2694   assert(stub != nullptr, "create runtime stub fail!");
2695   return stub;
2696 }
2697 
2698 #if INCLUDE_JFR
2699 
2700 static void jfr_prologue(address the_pc, MacroAssembler* masm, Register thread) {
2701   __ set_last_Java_frame(sp, fp, the_pc, t0);
2702   __ mv(c_rarg0, thread);
2703 }
2704 
2705 static void jfr_epilogue(MacroAssembler* masm) {
2706   __ reset_last_Java_frame(true);
2707 }
2708 // For c2: c_rarg0 is junk, call to runtime to write a checkpoint.
2709 // It returns a jobject handle to the event writer.
2710 // The handle is dereferenced and the return value is the event writer oop.
2711 RuntimeStub* SharedRuntime::generate_jfr_write_checkpoint() {
2712   enum layout {
2713     fp_off,
2714     fp_off2,
2715     return_off,
2716     return_off2,
2717     framesize // inclusive of return address
2718   };
2719 
2720   int insts_size = 1024;
2721   int locs_size = 64;
2722   const char* name = SharedRuntime::stub_name(StubId::shared_jfr_write_checkpoint_id);
2723   CodeBuffer code(name, insts_size, locs_size);
2724   OopMapSet* oop_maps = new OopMapSet();
2725   MacroAssembler* masm = new MacroAssembler(&code);
2726 
2727   address start = __ pc();
2728   __ enter();
2729   int frame_complete = __ pc() - start;
2730   address the_pc = __ pc();
2731   jfr_prologue(the_pc, masm, xthread);
2732   __ call_VM_leaf(CAST_FROM_FN_PTR(address, JfrIntrinsicSupport::write_checkpoint), 1);
2733 
2734   jfr_epilogue(masm);
2735   __ resolve_global_jobject(x10, t0, t1);
2736   __ leave();
2737   __ ret();
2738 
2739   OopMap* map = new OopMap(framesize, 1);
2740   oop_maps->add_gc_map(the_pc - start, map);
2741 
2742   RuntimeStub* stub = // codeBlob framesize is in words (not VMRegImpl::slot_size)
2743     RuntimeStub::new_runtime_stub(name, &code, frame_complete,
2744                                   (framesize >> (LogBytesPerWord - LogBytesPerInt)),
2745                                   oop_maps, false);
2746   return stub;
2747 }
2748 
2749 // For c2: call to return a leased buffer.
2750 RuntimeStub* SharedRuntime::generate_jfr_return_lease() {
2751   enum layout {
2752     fp_off,
2753     fp_off2,
2754     return_off,
2755     return_off2,
2756     framesize // inclusive of return address
2757   };
2758 
2759   int insts_size = 1024;
2760   int locs_size = 64;
2761   const char* name = SharedRuntime::stub_name(StubId::shared_jfr_return_lease_id);
2762   CodeBuffer code(name, insts_size, locs_size);
2763   OopMapSet* oop_maps = new OopMapSet();
2764   MacroAssembler* masm = new MacroAssembler(&code);
2765 
2766   address start = __ pc();
2767   __ enter();
2768   int frame_complete = __ pc() - start;
2769   address the_pc = __ pc();
2770   jfr_prologue(the_pc, masm, xthread);
2771   __ call_VM_leaf(CAST_FROM_FN_PTR(address, JfrIntrinsicSupport::return_lease), 1);
2772 
2773   jfr_epilogue(masm);
2774   __ leave();
2775   __ ret();
2776 
2777   OopMap* map = new OopMap(framesize, 1);
2778   oop_maps->add_gc_map(the_pc - start, map);
2779 
2780   RuntimeStub* stub = // codeBlob framesize is in words (not VMRegImpl::slot_size)
2781     RuntimeStub::new_runtime_stub(name, &code, frame_complete,
2782                                   (framesize >> (LogBytesPerWord - LogBytesPerInt)),
2783                                   oop_maps, false);
2784   return stub;
2785 }
2786 
2787 #endif // INCLUDE_JFR
2788 
2789 #if INCLUDE_SHENANDOAHGC
2790 RuntimeStub* SharedRuntime::generate_shenandoah_stub(StubId stub_id) {
2791   assert(UseShenandoahGC, "Only generate when Shenandoah is enabled");
2792 
2793   const char* name = SharedRuntime::stub_name(stub_id);
2794   address stub_addr = nullptr;
2795   bool returns_obj = true;
2796 
2797   switch (stub_id) {
2798     case StubId::shared_shenandoah_keepalive_id:
2799     case StubId::shared_shenandoah_keepalive_vectors_id: {
2800       stub_addr = CAST_FROM_FN_PTR(address, ShenandoahRuntime::write_barrier_pre);
2801       returns_obj = false;
2802       break;
2803     }
2804     case StubId::shared_shenandoah_lrb_strong_id:
2805     case StubId::shared_shenandoah_lrb_strong_vectors_id: {
2806       stub_addr = CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_strong);
2807       break;
2808     }
2809     case StubId::shared_shenandoah_lrb_weak_id:
2810     case StubId::shared_shenandoah_lrb_weak_vectors_id: {
2811       stub_addr = CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_weak);
2812       break;
2813     }
2814     case StubId::shared_shenandoah_lrb_phantom_id:
2815     case StubId::shared_shenandoah_lrb_phantom_vectors_id: {
2816       stub_addr = CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_phantom);
2817       break;
2818     }
2819     case StubId::shared_shenandoah_lrb_strong_narrow_id:
2820     case StubId::shared_shenandoah_lrb_strong_narrow_vectors_id: {
2821       stub_addr = CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_strong_narrow);
2822       break;
2823     }
2824     case StubId::shared_shenandoah_lrb_weak_narrow_id:
2825     case StubId::shared_shenandoah_lrb_weak_narrow_vectors_id: {
2826       stub_addr = CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_weak_narrow);
2827       break;
2828     }
2829     case StubId::shared_shenandoah_lrb_phantom_narrow_id:
2830     case StubId::shared_shenandoah_lrb_phantom_narrow_vectors_id: {
2831       stub_addr = CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_phantom_narrow);
2832       break;
2833     }
2834     default:
2835       ShouldNotReachHere();
2836   }
2837 
2838   bool save_vectors = true;
2839   switch (stub_id) {
2840     case StubId::shared_shenandoah_keepalive_vectors_id:
2841     case StubId::shared_shenandoah_lrb_strong_vectors_id:
2842     case StubId::shared_shenandoah_lrb_weak_vectors_id:
2843     case StubId::shared_shenandoah_lrb_phantom_vectors_id:
2844     case StubId::shared_shenandoah_lrb_strong_narrow_vectors_id:
2845     case StubId::shared_shenandoah_lrb_weak_narrow_vectors_id:
2846     case StubId::shared_shenandoah_lrb_phantom_narrow_vectors_id: {
2847       save_vectors = true;
2848       break;
2849     }
2850     case StubId::shared_shenandoah_keepalive_id:
2851     case StubId::shared_shenandoah_lrb_strong_id:
2852     case StubId::shared_shenandoah_lrb_weak_id:
2853     case StubId::shared_shenandoah_lrb_phantom_id:
2854     case StubId::shared_shenandoah_lrb_strong_narrow_id:
2855     case StubId::shared_shenandoah_lrb_weak_narrow_id:
2856     case StubId::shared_shenandoah_lrb_phantom_narrow_id: {
2857       save_vectors = false;
2858       break;
2859     }
2860     default:
2861       ShouldNotReachHere();
2862   }
2863 
2864   CodeBuffer code(name, 2048, 64);
2865   MacroAssembler* masm = new MacroAssembler(&code);
2866   address start = __ pc();
2867 
2868   int frame_size_in_words;
2869   RegisterSaver reg_save(save_vectors);
2870   OopMap* map = reg_save.save_live_registers(masm, 0, &frame_size_in_words);
2871   address frame_complete_pc = __ pc();
2872 
2873   // Call the runtime, but keep exact post-call PC for the oop map.
2874   int32_t offset = 0;
2875   __ movptr(t1, stub_addr, offset, t0);
2876   __ jalr(t1, offset);
2877   address post_call_pc = __ pc();
2878 
2879   if (returns_obj) {
2880     // RegisterSaver would clobber the call result when restoring.
2881     // Carry the result out of this stub by overwriting saved x10/a0.
2882     __ sd(x10, Address(sp, reg_save.reg_offset_in_bytes(x10)));
2883   }
2884 
2885   OopMapSet* oop_maps = new OopMapSet();
2886   oop_maps->add_gc_map(post_call_pc - start, map);
2887 
2888   reg_save.restore_live_registers(masm);
2889   __ ret();
2890 
2891   return RuntimeStub::new_runtime_stub(name,
2892                                        &code,
2893                                        frame_complete_pc - start,
2894                                        frame_size_in_words,
2895                                        oop_maps,
2896                                        true);
2897 }
2898 #endif