text: /*
   * Copyright (c) 2008, 2018, Oracle and/or its affiliates. All rights reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.
   *
   * This code is distributed in the hope that it will be useful, but WITHOUT
   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
   * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
   * version 2 for more details (a copy is included in the LICENSE file that
   * accompanied this code).
   *
   * You should have received a copy of the GNU General Public License version
   * 2 along with this work; if not, write to the Free Software Foundation,
   * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   *
   * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
   * or visit www.oracle.com if you need additional information or have any
   * questions.
   *
   */
  
  // This file mirror as much as possible methodHandles_x86.cpp to ease
  // cross platform development for JSR292.
  // Last synchronization: changeset f8c9417e3571
  
  #include "precompiled.hpp"
  #include "jvm.h"
  #include "classfile/javaClasses.inline.hpp"
  #include "interpreter/interpreter.hpp"
  #include "interpreter/interpreterRuntime.hpp"
  #include "memory/allocation.inline.hpp"
  #include "memory/resourceArea.hpp"
  #include "prims/methodHandles.hpp"
  #include "runtime/frame.inline.hpp"
  #include "utilities/preserveException.hpp"
  
  #define __ _masm->
  
  #ifdef PRODUCT
  #define BLOCK_COMMENT(str) /* nothing */
  #else
  #define BLOCK_COMMENT(str) __ block_comment(str)
  #endif
  
  #define BIND(label) bind(label); BLOCK_COMMENT(#label ":")
  
  void MethodHandles::load_klass_from_Class(MacroAssembler* _masm, Register klass_reg, Register temp1, Register temp2) {
    if (VerifyMethodHandles) {
      verify_klass(_masm, klass_reg, temp1, temp2, SystemDictionary::WK_KLASS_ENUM_NAME(java_lang_Class),
                   "MH argument is a Class");
    }
    __ ldr(klass_reg, Address(klass_reg, java_lang_Class::klass_offset_in_bytes()));
  }
  
  #ifdef ASSERT
  static int check_nonzero(const char* xname, int x) {
    assert(x != 0, "%s should be nonzero", xname);
    return x;
  }
  #define NONZERO(x) check_nonzero(#x, x)
  #else //ASSERT
  #define NONZERO(x) (x)
  #endif //ASSERT
  
  #ifdef ASSERT
  void MethodHandles::verify_klass(MacroAssembler* _masm,
                                   Register obj, Register temp1, Register temp2, SystemDictionary::WKID klass_id,
                                   const char* error_message) {
    InstanceKlass** klass_addr = SystemDictionary::well_known_klass_addr(klass_id);
    Klass* klass = SystemDictionary::well_known_klass(klass_id);
    Label L_ok, L_bad;
    BLOCK_COMMENT("verify_klass {");
    __ verify_oop(obj);
    __ cbz(obj, L_bad);
    __ load_klass(temp1, obj);
    __ lea(temp2, ExternalAddress((address) klass_addr));
    __ ldr(temp2, temp2); // the cmpptr on x86 dereferences the AddressLiteral (not lea)
    __ cmp(temp1, temp2);
    __ b(L_ok, eq);
    intptr_t super_check_offset = klass->super_check_offset();
    __ ldr(temp1, Address(temp1, super_check_offset));
    __ cmp(temp1, temp2);
    __ b(L_ok, eq);
  
    __ bind(L_bad);
    __ stop(error_message);
    __ BIND(L_ok);
    BLOCK_COMMENT("} verify_klass");
  }
  
  void MethodHandles::verify_ref_kind(MacroAssembler* _masm, int ref_kind, Register member_reg, Register temp) {
    Label L;
    BLOCK_COMMENT("verify_ref_kind {");
    __ ldr_u32(temp, Address(member_reg, NONZERO(java_lang_invoke_MemberName::flags_offset_in_bytes())));
    __ logical_shift_right(temp, temp, java_lang_invoke_MemberName::MN_REFERENCE_KIND_SHIFT);
    __ andr(temp, temp, (unsigned)java_lang_invoke_MemberName::MN_REFERENCE_KIND_MASK);
    __ cmp(temp, ref_kind);
    __ b(L, eq);
    { char* buf = NEW_C_HEAP_ARRAY(char, 100, mtInternal);
    jio_snprintf(buf, 100, "verify_ref_kind expected %x", ref_kind);
    if (ref_kind == JVM_REF_invokeVirtual ||
        ref_kind == JVM_REF_invokeSpecial)
      // could do this for all ref_kinds, but would explode assembly code size
      trace_method_handle(_masm, buf);
    __ stop(buf);
    }
    BLOCK_COMMENT("} verify_ref_kind");
    __ bind(L);
  }
  
  #endif //ASSERT
  
  void MethodHandles::jump_from_method_handle(MacroAssembler* _masm, bool for_compiler_entry) {
    Label L_no_such_method;
    __ cbz(Rmethod, L_no_such_method);
  
    // Note: JVMTI overhead seems small enough compared to invocation
    // cost and is not worth the complexity or code size overhead of
    // supporting several variants of each adapter.
    if (!for_compiler_entry && (JvmtiExport::can_post_interpreter_events())) {
      // JVMTI events, such as single-stepping, are implemented partly by avoiding running
      // compiled code in threads for which the event is enabled.  Check here for
      // interp_only_mode if these events CAN be enabled.
      __ ldr_s32(Rtemp, Address(Rthread, JavaThread::interp_only_mode_offset()));
  #ifdef AARCH64
      Label L;
      __ cbz(Rtemp, L);
      __ indirect_jump(Address(Rmethod, Method::interpreter_entry_offset()), Rtemp);
      __ bind(L);
  #else
      __ cmp(Rtemp, 0);
      __ ldr(PC, Address(Rmethod, Method::interpreter_entry_offset()), ne);
  #endif // AARCH64
    }
    const ByteSize entry_offset = for_compiler_entry ? Method::from_compiled_offset() :
                                                       Method::from_interpreted_offset();
  
    __ indirect_jump(Address(Rmethod, entry_offset), Rtemp);
  
    __ bind(L_no_such_method);
    // throw exception
    __ jump(StubRoutines::throw_AbstractMethodError_entry(), relocInfo::runtime_call_type, Rtemp);
  }
  
  void MethodHandles::jump_to_lambda_form(MacroAssembler* _masm,
                                          Register recv, Register tmp,
                                          bool for_compiler_entry) {
    BLOCK_COMMENT("jump_to_lambda_form {");
    // This is the initial entry point of a lazy method handle.
    // After type checking, it picks up the invoker from the LambdaForm.
    assert_different_registers(recv, tmp, Rmethod);
  
    // Load the invoker, as MH -> MH.form -> LF.vmentry
    __ load_heap_oop(tmp, Address(recv, NONZERO(java_lang_invoke_MethodHandle::form_offset_in_bytes())));
    __ verify_oop(tmp);
  
    __ load_heap_oop(tmp, Address(tmp, NONZERO(java_lang_invoke_LambdaForm::vmentry_offset_in_bytes())));
    __ verify_oop(tmp);
  
    __ load_heap_oop(Rmethod, Address(tmp, NONZERO(java_lang_invoke_MemberName::method_offset_in_bytes())));
    __ verify_oop(Rmethod);
    __ ldr(Rmethod, Address(Rmethod, NONZERO(java_lang_invoke_ResolvedMethodName::vmtarget_offset_in_bytes())));
  
    if (VerifyMethodHandles && !for_compiler_entry) {
      // make sure recv is already on stack
      __ ldr(tmp, Address(Rmethod, Method::const_offset()));
      __ load_sized_value(tmp,
                          Address(tmp, ConstMethod::size_of_parameters_offset()),
                          sizeof(u2), /*is_signed*/ false);
      // assert(sizeof(u2) == sizeof(Method::_size_of_parameters), "");
      Label L;
      __ ldr(tmp, __ receiver_argument_address(Rparams, tmp, tmp));
      __ cmp(tmp, recv);
      __ b(L, eq);
      __ stop("receiver not on stack");
      __ bind(L);
    }
  
    jump_from_method_handle(_masm, for_compiler_entry);
    BLOCK_COMMENT("} jump_to_lambda_form");
  }
  
  
  // Code generation
  address MethodHandles::generate_method_handle_interpreter_entry(MacroAssembler* _masm,
                                                                  vmIntrinsics::ID iid) {
    const bool not_for_compiler_entry = false;  // this is the interpreter entry
    assert(is_signature_polymorphic(iid), "expected invoke iid");
    if (iid == vmIntrinsics::_invokeGeneric ||
        iid == vmIntrinsics::_compiledLambdaForm) {
      // Perhaps surprisingly, the user-visible names, and linkToCallSite, are not directly used.
      // They are linked to Java-generated adapters via MethodHandleNatives.linkMethod.
      // They all require an extra argument.
      __ should_not_reach_here();           // empty stubs make SG sick
      return NULL;
    }
  
    // Rmethod: Method*
    // Rparams (SP on 32-bit ARM): pointer to parameters
    // Rsender_sp (R4/R19): sender SP (must preserve; see prepare_to_jump_from_interpreted)
    // R5_mh: receiver method handle (must load from sp[MethodTypeForm.vmslots])
    // R1, R2, Rtemp: garbage temp, blown away
  
    // Use same name as x86 to ease future merges
    Register rdx_temp       = R2_tmp;
    Register rdx_param_size = rdx_temp;  // size of parameters
    Register rax_temp       = R1_tmp;
    Register rcx_mh         = R5_mh;     // MH receiver; dies quickly and is recycled
    Register rbx_method     = Rmethod;   // eventual target of this invocation
    Register rdi_temp       = Rtemp;
  
    // here's where control starts out:
    __ align(CodeEntryAlignment);
    address entry_point = __ pc();
  
    if (VerifyMethodHandles) {
      Label L;
      BLOCK_COMMENT("verify_intrinsic_id {");
      __ ldrh(rdi_temp, Address(rbx_method, Method::intrinsic_id_offset_in_bytes()));
      __ sub_slow(rdi_temp, rdi_temp, (int) iid);
      __ cbz(rdi_temp, L);
      if (iid == vmIntrinsics::_linkToVirtual ||
          iid == vmIntrinsics::_linkToSpecial) {
        // could do this for all kinds, but would explode assembly code size
        trace_method_handle(_masm, "bad Method*::intrinsic_id");
      }
      __ stop("bad Method*::intrinsic_id");
      __ bind(L);
      BLOCK_COMMENT("} verify_intrinsic_id");
    }
  
    // First task:  Find out how big the argument list is.
    Address rdx_first_arg_addr;
    int ref_kind = signature_polymorphic_intrinsic_ref_kind(iid);
    assert(ref_kind != 0 || iid == vmIntrinsics::_invokeBasic, "must be _invokeBasic or a linkTo intrinsic");
    if (ref_kind == 0 || MethodHandles::ref_kind_has_receiver(ref_kind)) {
      __ ldr(rdx_param_size, Address(rbx_method, Method::const_offset()));
      __ load_sized_value(rdx_param_size,
                          Address(rdx_param_size, ConstMethod::size_of_parameters_offset()),
                          sizeof(u2), /*is_signed*/ false);
      // assert(sizeof(u2) == sizeof(Method::_size_of_parameters), "");
      rdx_first_arg_addr = __ receiver_argument_address(Rparams, rdx_param_size, rdi_temp);
    } else {
      DEBUG_ONLY(rdx_param_size = noreg);
    }
  
    if (!is_signature_polymorphic_static(iid)) {
      __ ldr(rcx_mh, rdx_first_arg_addr);
      DEBUG_ONLY(rdx_param_size = noreg);
    }
  
    // rdx_first_arg_addr is live!
  
    trace_method_handle_interpreter_entry(_masm, iid);
  
    if (iid == vmIntrinsics::_invokeBasic) {
      generate_method_handle_dispatch(_masm, iid, rcx_mh, noreg, not_for_compiler_entry);
  
    } else {
      // Adjust argument list by popping the trailing MemberName argument.
      Register rcx_recv = noreg;
      if (MethodHandles::ref_kind_has_receiver(ref_kind)) {
        // Load the receiver (not the MH; the actual MemberName's receiver) up from the interpreter stack.
        __ ldr(rcx_recv = rcx_mh, rdx_first_arg_addr);
        DEBUG_ONLY(rdx_param_size = noreg);
      }
      Register rbx_member = rbx_method;  // MemberName ptr; incoming method ptr is dead now
  #ifdef AARCH64
      __ ldr(rbx_member, Address(Rparams, Interpreter::stackElementSize, post_indexed));
  #else
      __ pop(rbx_member);
  #endif
      generate_method_handle_dispatch(_masm, iid, rcx_recv, rbx_member, not_for_compiler_entry);
    }
    return entry_point;
  }
  
  void MethodHandles::generate_method_handle_dispatch(MacroAssembler* _masm,
                                                      vmIntrinsics::ID iid,
                                                      Register receiver_reg,
                                                      Register member_reg,
                                                      bool for_compiler_entry) {
    assert(is_signature_polymorphic(iid), "expected invoke iid");
    // Use same name as x86 to ease future merges
    Register rbx_method = Rmethod;   // eventual target of this invocation
    // temps used in this code are not used in *either* compiled or interpreted calling sequences
    Register temp1 = (for_compiler_entry ? saved_last_sp_register() : R1_tmp);
    Register temp2 = AARCH64_ONLY(R9) NOT_AARCH64(R8);
    Register temp3 = Rtemp; // R12/R16
    Register temp4 = AARCH64_ONLY(Rtemp2) NOT_AARCH64(R5);
    if (for_compiler_entry) {
      assert(receiver_reg == (iid == vmIntrinsics::_linkToStatic ? noreg : j_rarg0), "only valid assignment");
  #ifdef AARCH64
      assert_different_registers(temp1, j_rarg0, j_rarg1, j_rarg2, j_rarg3, j_rarg4, j_rarg5, j_rarg6, j_rarg7);
      assert_different_registers(temp2, j_rarg0, j_rarg1, j_rarg2, j_rarg3, j_rarg4, j_rarg5, j_rarg6, j_rarg7);
      assert_different_registers(temp3, j_rarg0, j_rarg1, j_rarg2, j_rarg3, j_rarg4, j_rarg5, j_rarg6, j_rarg7);
      assert_different_registers(temp4, j_rarg0, j_rarg1, j_rarg2, j_rarg3, j_rarg4, j_rarg5, j_rarg6, j_rarg7);
  #else
      assert_different_registers(temp1, j_rarg0, j_rarg1, j_rarg2, j_rarg3);
      assert_different_registers(temp2, j_rarg0, j_rarg1, j_rarg2, j_rarg3);
      assert_different_registers(temp3, j_rarg0, j_rarg1, j_rarg2, j_rarg3);
      assert_different_registers(temp4, j_rarg0, j_rarg1, j_rarg2, j_rarg3);
  #endif // AARCH64
    }
    assert_different_registers(temp1, temp2, temp3, receiver_reg);
    assert_different_registers(temp1, temp2, temp3, temp4, member_reg);
    if (!for_compiler_entry)
      assert_different_registers(temp1, temp2, temp3, temp4, saved_last_sp_register());  // don't trash lastSP
  
    if (iid == vmIntrinsics::_invokeBasic) {
      // indirect through MH.form.exactInvoker.vmtarget
      jump_to_lambda_form(_masm, receiver_reg, temp3, for_compiler_entry);
  
    } else {
      // The method is a member invoker used by direct method handles.
      if (VerifyMethodHandles) {
        // make sure the trailing argument really is a MemberName (caller responsibility)
        verify_klass(_masm, member_reg, temp2, temp3, SystemDictionary::WK_KLASS_ENUM_NAME(java_lang_invoke_MemberName),
                     "MemberName required for invokeVirtual etc.");
      }
  
      Address member_clazz(   member_reg, NONZERO(java_lang_invoke_MemberName::clazz_offset_in_bytes()));
      Address member_vmindex( member_reg, NONZERO(java_lang_invoke_MemberName::vmindex_offset_in_bytes()));
      Address member_vmtarget(member_reg, NONZERO(java_lang_invoke_MemberName::method_offset_in_bytes()));
      Address vmtarget_method(Rmethod, NONZERO(java_lang_invoke_ResolvedMethodName::vmtarget_offset_in_bytes()));
  
      Register temp1_recv_klass = temp1;
      if (iid != vmIntrinsics::_linkToStatic) {
        if (iid == vmIntrinsics::_linkToSpecial) {
          // Don't actually load the klass; just null-check the receiver.
          __ null_check(receiver_reg, temp3);
        } else {
          // load receiver klass itself
          __ null_check(receiver_reg, temp3, oopDesc::klass_offset_in_bytes());
          __ load_klass(temp1_recv_klass, receiver_reg);
          __ verify_klass_ptr(temp1_recv_klass);
        }
        BLOCK_COMMENT("check_receiver {");
        // The receiver for the MemberName must be in receiver_reg.
        // Check the receiver against the MemberName.clazz
        if (VerifyMethodHandles && iid == vmIntrinsics::_linkToSpecial) {
          // Did not load it above...
          __ load_klass(temp1_recv_klass, receiver_reg);
          __ verify_klass_ptr(temp1_recv_klass);
        }
        // Check the receiver against the MemberName.clazz
        if (VerifyMethodHandles && iid != vmIntrinsics::_linkToInterface) {
          Label L_ok;
          Register temp2_defc = temp2;
          __ load_heap_oop(temp2_defc, member_clazz);
          load_klass_from_Class(_masm, temp2_defc, temp3, temp4);
          __ verify_klass_ptr(temp2_defc);
  #ifdef AARCH64
          // TODO-AARCH64
          __ b(L_ok);
  #else
          __ check_klass_subtype(temp1_recv_klass, temp2_defc, temp3, temp4, noreg, L_ok);
  #endif
          // If we get here, the type check failed!
          __ stop("receiver class disagrees with MemberName.clazz");
          __ bind(L_ok);
        }
        BLOCK_COMMENT("} check_receiver");
      }
      if (iid == vmIntrinsics::_linkToSpecial ||
          iid == vmIntrinsics::_linkToStatic) {
        DEBUG_ONLY(temp1_recv_klass = noreg);  // these guys didn't load the recv_klass
      }
  
      // Live registers at this point:
      //  member_reg - MemberName that was the extra argument
      //  temp1_recv_klass - klass of stacked receiver, if needed
  
      Label L_incompatible_class_change_error;
      switch (iid) {
      case vmIntrinsics::_linkToSpecial:
        if (VerifyMethodHandles) {
          verify_ref_kind(_masm, JVM_REF_invokeSpecial, member_reg, temp3);
        }
        __ load_heap_oop(Rmethod, member_vmtarget);
        __ ldr(Rmethod, vmtarget_method);
        break;
  
      case vmIntrinsics::_linkToStatic:
        if (VerifyMethodHandles) {
          verify_ref_kind(_masm, JVM_REF_invokeStatic, member_reg, temp3);
        }
        __ load_heap_oop(Rmethod, member_vmtarget);
        __ ldr(Rmethod, vmtarget_method);
        break;
        break;
  
      case vmIntrinsics::_linkToVirtual:
      {
        // same as TemplateTable::invokevirtual,
        // minus the CP setup and profiling:
  
        if (VerifyMethodHandles) {
          verify_ref_kind(_masm, JVM_REF_invokeVirtual, member_reg, temp3);
        }
  
        // pick out the vtable index from the MemberName, and then we can discard it:
        Register temp2_index = temp2;
        __ ldr(temp2_index, member_vmindex);
  
        if (VerifyMethodHandles) {
          Label L_index_ok;
          __ cmp(temp2_index, 0);
          __ b(L_index_ok, ge);
          __ stop("no virtual index");
          __ bind(L_index_ok);
        }
  
        // Note:  The verifier invariants allow us to ignore MemberName.clazz and vmtarget
        // at this point.  And VerifyMethodHandles has already checked clazz, if needed.
  
        // get target Method* & entry point
        __ lookup_virtual_method(temp1_recv_klass, temp2_index, Rmethod);
        break;
      }
  
      case vmIntrinsics::_linkToInterface:
      {
        // same as TemplateTable::invokeinterface
        // (minus the CP setup and profiling, with different argument motion)
        if (VerifyMethodHandles) {
          verify_ref_kind(_masm, JVM_REF_invokeInterface, member_reg, temp3);
        }
  
        Register temp3_intf = temp3;
        __ load_heap_oop(temp3_intf, member_clazz);
        load_klass_from_Class(_masm, temp3_intf, temp2, temp4);
        __ verify_klass_ptr(temp3_intf);
  
        Register rbx_index = rbx_method;
        __ ldr(rbx_index, member_vmindex);
        if (VerifyMethodHandles) {
          Label L;
          __ cmp(rbx_index, 0);
          __ b(L, ge);
          __ stop("invalid vtable index for MH.invokeInterface");
          __ bind(L);
        }
  
        // given intf, index, and recv klass, dispatch to the implementation method
        Label L_no_such_interface;
        __ lookup_interface_method(temp1_recv_klass, temp3_intf,
                                   // note: next two args must be the same:
                                   rbx_index, rbx_method,
                                   temp2, temp4,
                                   L_incompatible_class_change_error);
        break;
      }
  
      default:
        fatal("unexpected intrinsic %d: %s", iid, vmIntrinsics::name_at(iid));
        break;
      }
  
      // Live at this point:
      //   Rmethod (target method)
      //   Rsender_sp, Rparams (if interpreted)
      //   register arguments (if compiled)
  
      // After figuring out which concrete method to call, jump into it.
      __ verify_method_ptr(Rmethod);
      jump_from_method_handle(_masm, for_compiler_entry);
  
      if (iid == vmIntrinsics::_linkToInterface) {
        __ bind(L_incompatible_class_change_error);
        __ jump(StubRoutines::throw_IncompatibleClassChangeError_entry(), relocInfo::runtime_call_type, Rtemp);
      }
    }
  }
  
  
  #ifndef PRODUCT
  enum {
    ARG_LIMIT = 255, SLOP = 4,
    // use this parameter for checking for garbage stack movements:
    UNREASONABLE_STACK_MOVE = (ARG_LIMIT + SLOP)
    // the slop defends against false alarms due to fencepost errors
  };
  
  #ifdef AARCH64
  const int trace_mh_nregs = 32; // R0-R30, PC
  #else
  const int trace_mh_nregs = 15;
  const Register trace_mh_regs[trace_mh_nregs] =
    {R0, R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, R11, R12, LR, PC};
  #endif // AARCH64
  
  void trace_method_handle_stub(const char* adaptername,
                                intptr_t* saved_regs,
                                intptr_t* saved_bp,
                                oop mh) {
    // called as a leaf from native code: do not block the JVM!
    bool has_mh = (strstr(adaptername, "/static") == NULL &&
                   strstr(adaptername, "linkTo") == NULL);    // static linkers don't have MH
    intptr_t* entry_sp = (intptr_t*) &saved_regs[trace_mh_nregs]; // just after the saved regs
    intptr_t* saved_sp = (intptr_t*)  saved_regs[Rsender_sp->encoding()]; // save of Rsender_sp
    intptr_t* last_sp  = (intptr_t*)  saved_bp[AARCH64_ONLY(frame::interpreter_frame_stack_top_offset) NOT_AARCH64(frame::interpreter_frame_last_sp_offset)];
    intptr_t* base_sp  = last_sp;
  
    intptr_t    mh_reg = (intptr_t)saved_regs[R5_mh->encoding()];
    const char* mh_reg_name = "R5_mh";
    if (!has_mh)  mh_reg_name = "R5";
    tty->print_cr("MH %s %s=" PTR_FORMAT " sp=(" PTR_FORMAT "+" INTX_FORMAT ") stack_size=" INTX_FORMAT " bp=" PTR_FORMAT,
                  adaptername, mh_reg_name, mh_reg,
                  (intptr_t)entry_sp, (intptr_t)saved_sp - (intptr_t)entry_sp, (intptr_t)(base_sp - last_sp), (intptr_t)saved_bp);
  
    if (last_sp != saved_sp && last_sp != NULL)
      tty->print_cr("*** last_sp=" INTPTR_FORMAT, p2i(last_sp));
    if (Verbose) {
      tty->print(" reg dump: ");
      int i;
      for (i = 0; i < trace_mh_nregs; i++) {
        if (i > 0 && i % AARCH64_ONLY(2) NOT_AARCH64(4) == 0)
          tty->print("\n   + dump: ");
  #ifdef AARCH64
        const char* reg_name = (i == trace_mh_nregs-1) ? "pc" : as_Register(i)->name();
  #else
        const char* reg_name = trace_mh_regs[i]->name();
  #endif
        tty->print(" %s: " INTPTR_FORMAT, reg_name, p2i((void *)saved_regs[i]));
      }
      tty->cr();
    }
  
    if (Verbose) {
      // dump last frame (from JavaThread::print_frame_layout)
  
      // Note: code is robust but the dumped informationm may not be
      // 100% correct, particularly with respect to the dumped
      // "unextended_sp". Getting it right for all trace_method_handle
      // call paths is not worth the complexity/risk. The correct slot
      // will be identified by *Rsender_sp anyway in the dump.
      JavaThread* p = JavaThread::active();
  
      ResourceMark rm;
      PRESERVE_EXCEPTION_MARK;
      FrameValues values;
  
      intptr_t* dump_fp = (intptr_t *) saved_bp;
      address dump_pc = (address) saved_regs[trace_mh_nregs-2]; // LR (with LR,PC last in saved_regs)
      frame dump_frame((intptr_t *)entry_sp, dump_fp, dump_pc);
  
      dump_frame.describe(values, 1);
      // mark Rsender_sp if seems valid
      if (has_mh) {
        if ((saved_sp >= entry_sp - UNREASONABLE_STACK_MOVE) && (saved_sp < dump_fp)) {
          values.describe(-1, saved_sp, "*Rsender_sp");
        }
      }
  
      // Note: the unextended_sp may not be correct
      tty->print_cr("  stack layout:");
      values.print(p);
    }
    if (Verbose) {
      if (has_mh && oopDesc::is_oop(mh)) {
        mh->print();
        if (java_lang_invoke_MethodHandle::is_instance(mh)) {
          if (java_lang_invoke_MethodHandle::form_offset_in_bytes() != 0)
            java_lang_invoke_MethodHandle::form(mh)->print();
        }
      }
    }
  }
  
  void MethodHandles::trace_method_handle(MacroAssembler* _masm, const char* adaptername) {
    if (!TraceMethodHandles)  return;
    BLOCK_COMMENT("trace_method_handle {");
    // register saving
    //  must correspond to trace_mh_nregs and trace_mh_regs defined above
    int push_size = __ save_all_registers();
    assert(trace_mh_nregs*wordSize == push_size,"saved register count mismatch");
  
    __ mov_slow(R0, adaptername);
    __ mov(R1, SP); // entry_sp (after pushes)
    __ mov(R2, FP);
    if (R5_mh != R3) {
      assert_different_registers(R0, R1, R2, R5_mh);
      __ mov(R3, R5_mh);
    }
  
    __ call_VM_leaf(CAST_FROM_FN_PTR(address, trace_method_handle_stub), R0, R1, R2, R3);
  
    __ restore_all_registers();
    BLOCK_COMMENT("} trace_method_handle");
  }
  #endif //PRODUCT
  