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 /*

  * Copyright (c) 1997, 2014, Oracle and/or its affiliates. All rights reserved.

  * Copyright (c) 2015, 2016, Loongson Technology. 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.

  *

  */

 #include "precompiled.hpp"

 #include "asm/macroAssembler.hpp"

 #include "interpreter/interpreter.hpp"

 #include "interpreter/interpreterRuntime.hpp"

 #include "memory/allocation.inline.hpp"

 #include "prims/methodHandles.hpp"

 #define __ _masm->

 #ifdef PRODUCT

 #define BLOCK_COMMENT(str) /* nothing */

 #define STOP(error) stop(error)

 #else

 #define BLOCK_COMMENT(str) __ block_comment(str)

 #define STOP(error) block_comment(error); __ stop(error)

 #endif

 #define BIND(label) bind(label); BLOCK_COMMENT(#label ":")

 void MethodHandles::load_klass_from_Class(MacroAssembler* _masm, Register klass_reg) {

   if (VerifyMethodHandles)

     verify_klass(_masm, klass_reg, SystemDictionary::WK_KLASS_ENUM_NAME(java_lang_Class),

                  "MH argument is a Class");

   __ ld(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, err_msg("%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, SystemDictionary::WKID klass_id,

                                  const char* error_message) {

 /*

   Klass** klass_addr = SystemDictionary::well_known_klass_addr(klass_id);

   KlassHandle klass = SystemDictionary::well_known_klass(klass_id);

   Register temp = S0;

 //  Register temp2 = noreg;

 //  LP64_ONLY(temp2 = S1);  // used by MacroAssembler::cmpptr

   Label L_ok, L_bad;

   BLOCK_COMMENT("verify_klass {");

   __ verify_oop(obj);

 //  __ testptr(obj, obj);

 //  __ jcc(Assembler::zero, L_bad);

   __ beq(obj, R0, L_bad);

   __ nop();

   __ push(temp); //if (temp2 != noreg)  __ push(temp2);

 #define UNPUSH {  __ pop(temp); }

   __ load_klass(temp, obj);

 //  __ cmpptr(temp, ExternalAddress((address) klass_addr));

 //  __ jcc(Assembler::equal, L_ok);

   __ li(AT, (long)&klass_addr);

   __ ld(AT, AT, 0);

   __ beq(temp, AT, L_ok);

   __ nop();

   intptr_t super_check_offset = klass->super_check_offset();

   __ ld(temp, Address(temp, super_check_offset));

 //  __ cmpptr(temp, ExternalAddress((address) klass_addr));

 //  __ jcc(Assembler::equal, L_ok);

   __ li(AT, (long)&klass_addr); 

   __ ld(AT, AT, 0);

   __ beq(AT, temp, L_ok);

   __ nop();

   UNPUSH;

   __ bind(L_bad);

   __ STOP(error_message);

   __ BIND(L_ok);

   UNPUSH;

   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 {");

   __ lw(temp, Address(member_reg, NONZERO(java_lang_invoke_MemberName::flags_offset_in_bytes())));

 //  __ shrl(temp, java_lang_invoke_MemberName::MN_REFERENCE_KIND_SHIFT);

   __ sra(temp, temp, java_lang_invoke_MemberName::MN_REFERENCE_KIND_SHIFT);

 //  __ andl(temp, java_lang_invoke_MemberName::MN_REFERENCE_KIND_MASK);

   __ move(AT, java_lang_invoke_MemberName::MN_REFERENCE_KIND_MASK);

   __ andr(temp, temp, AT);

 //  __ cmpl(temp, ref_kind);

 //  __ jcc(Assembler::equal, L);

   __ move(AT, ref_kind);

   __ beq(temp, AT, L);

   __ nop();

   { 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, Register method, Register temp,

                                             bool for_compiler_entry) {

   assert(method == Rmethod, "interpreter calling convention");

    Label L_no_such_method;

    __ beq(method, R0, L_no_such_method);

    __ nop();

   __ verify_method_ptr(method);

   if (!for_compiler_entry && JvmtiExport::can_post_interpreter_events()) {

     Label run_compiled_code;

     // 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.

 #ifdef _LP64

     Register rthread = TREG;

 #else

     Register rthread = temp;

     __ get_thread(rthread);

 #endif

     // interp_only is an int, on little endian it is sufficient to test the byte only

     // Is a cmpl faster?

 //    __ cmpb(Address(rthread, JavaThread::interp_only_mode_offset()), 0);

     __ lbu(AT, rthread, in_bytes(JavaThread::interp_only_mode_offset()));

 //    __ jccb(Assembler::zero, run_compiled_code);

     __ beq(AT, R0, run_compiled_code);

     __ nop();

 //    __ jmp(Address(method, Method::interpreter_entry_offset()));

     __ ld(T9, method, in_bytes(Method::interpreter_entry_offset()));

     __ jr(T9);

     __ nop();

     __ BIND(run_compiled_code);

   }

   const ByteSize entry_offset = for_compiler_entry ? Method::from_compiled_offset() :

                                                      Method::from_interpreted_offset();

 //  __ jmp(Address(method, entry_offset));

   __ ld(T9, method, in_bytes(entry_offset));

   __ jr(T9);

   __ nop();

   __ bind(L_no_such_method);

 //  __ jump(RuntimeAddress(StubRoutines::throw_AbstractMethodError_entry()));

   address wrong_method = StubRoutines::throw_AbstractMethodError_entry();

   __ jmp(wrong_method, relocInfo::runtime_call_type);

   __ nop();

 }

 void MethodHandles::jump_to_lambda_form(MacroAssembler* _masm,

                                         Register recv, Register method_temp,

                                         Register temp2,

                                         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, method_temp, temp2);

   assert(recv != noreg, "required register");

   assert(method_temp == Rmethod, "required register for loading method");

   //NOT_PRODUCT({ FlagSetting fs(TraceMethodHandles, true); trace_method_handle(_masm, "LZMH"); });

   // Load the invoker, as MH -> MH.form -> LF.vmentry

   __ verify_oop(recv);

   __ load_heap_oop(method_temp, Address(recv, NONZERO(java_lang_invoke_MethodHandle::form_offset_in_bytes())));

   __ verify_oop(method_temp);

   __ load_heap_oop(method_temp, Address(method_temp, NONZERO(java_lang_invoke_LambdaForm::vmentry_offset_in_bytes())));

   __ verify_oop(method_temp);

   // the following assumes that a Method* is normally compressed in the vmtarget field:

 //  __ movptr(method_temp, Address(method_temp, NONZERO(java_lang_invoke_MemberName::vmtarget_offset_in_bytes())));

   __ ld(method_temp, Address(method_temp, NONZERO(java_lang_invoke_MemberName::vmtarget_offset_in_bytes())));

   if (VerifyMethodHandles && !for_compiler_entry) {

     // make sure recv is already on stack

 //    __ movptr(temp2, Address(method_temp, Method::const_offset()));

     __ ld(temp2, Address(method_temp, Method::const_offset()));

     __ load_sized_value(temp2,

                         Address(temp2, ConstMethod::size_of_parameters_offset()),

                         sizeof(u2), false);

     // assert(sizeof(u2) == sizeof(Method::_size_of_parameters), "");

     Label L;

 //    __ cmpptr(recv, __ argument_address(temp2, -1));

 //    __ jcc(Assembler::equal, L);

     Address recv_addr = __ argument_address(temp2, -1);

     __ ld(AT, recv_addr);

     __ beq(recv, AT, L);

     __ nop();

 //    __ movptr(rax, __ argument_address(temp2, -1));

     recv_addr = __ argument_address(temp2, -1);

     __ ld(V0, recv_addr);

     __ STOP("receiver not on stack");

     __ BIND(L);

   }

   jump_from_method_handle(_masm, method_temp, temp2, 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 symbolic references visible to Java are not directly used.

     // They are linked to Java-generated adapters via MethodHandleNatives.linkMethod.

     // They all allow an appendix argument.

 //    __ hlt();           // empty stubs make SG sick

     __ stop("empty stubs make SG sick");

     return NULL;

   }

   // rsi/r13: sender SP (must preserve; see prepare_to_jump_from_interpreted)

   // rbx: Method*

   // rdx: argument locator (parameter slot count, added to rsp)

   // rcx: used as temp to hold mh or receiver

   // rax, rdi: garbage temps, blown away

   Register rdx_argp   = T9;   // argument list ptr, live on error paths

 //  Register rax_temp   = rax;

   Register rcx_mh     = S7;   // MH receiver; dies quickly and is recycled

   Register rbx_method = Rmethod;   // eventual target of this invocation

   // here's where control starts out:

   __ align(CodeEntryAlignment);

   address entry_point = __ pc();

   if (VerifyMethodHandles) {

     Label L;

     BLOCK_COMMENT("verify_intrinsic_id {");

 //    __ cmpb(Address(rbx_method, Method::intrinsic_id_offset_in_bytes()), (int) iid);

 //    __ jcc(Assembler::equal, L);

     __ lbu(AT, rbx_method, Method::intrinsic_id_offset_in_bytes());

     guarantee(Assembler::is_simm16(iid), "Oops, iid is not simm16! Change the instructions.");

     __ addiu(AT, AT, -1 * (int) iid); 

     __ beq(AT, R0, L);

     __ nop();

     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)) {

     __ ld(rdx_argp, Address(rbx_method, Method::const_offset()));

     __ load_sized_value(rdx_argp,

                         Address(rdx_argp, ConstMethod::size_of_parameters_offset()),

                         sizeof(u2), false);

     // assert(sizeof(u2) == sizeof(Method::_size_of_parameters), "");

     rdx_first_arg_addr = __ argument_address(rdx_argp, -1);

   } else {

     DEBUG_ONLY(rdx_argp = noreg);

   }

   if (!is_signature_polymorphic_static(iid)) {

     __ ld(rcx_mh, rdx_first_arg_addr);

     DEBUG_ONLY(rdx_argp = 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.

       __ ld(rcx_recv = T2, rdx_first_arg_addr);

     }

     DEBUG_ONLY(rdx_argp = noreg);

     Register rbx_member = rbx_method;  // MemberName ptr; incoming method ptr is dead now

 //    __ pop(AT);           // return address

     __ pop(rbx_member);         // extract last argument

 //    __ push(AT);          // re-push return address

     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");

   Register rbx_method = Rmethod;   // eventual target of this invocation

   // temps used in this code are not used in *either* compiled or interpreted calling sequences

 #ifdef _LP64

   Register j_rarg0 = T0;

   Register j_rarg1 = A0;

   Register j_rarg2 = A1;

   Register j_rarg3 = A2;

   Register j_rarg4 = A3;

   Register j_rarg5 = A4;

   Register temp1 = T8;

   Register temp2 = T9;

   Register temp3 = V0;

   if (for_compiler_entry) {

     assert(receiver_reg == (iid == vmIntrinsics::_linkToStatic ? noreg : j_rarg0), "only valid assignment");

     assert_different_registers(temp1,        j_rarg0, j_rarg1, j_rarg2, j_rarg3, j_rarg4, j_rarg5);

     assert_different_registers(temp2,        j_rarg0, j_rarg1, j_rarg2, j_rarg3, j_rarg4, j_rarg5);

     assert_different_registers(temp3,        j_rarg0, j_rarg1, j_rarg2, j_rarg3, j_rarg4, j_rarg5);

   }

 #else

 /*

   Register temp1 = (for_compiler_entry ? rsi : rdx);

   Register temp2 = rdi;

   Register temp3 = rax;

   if (for_compiler_entry) {

     assert(receiver_reg == (iid == vmIntrinsics::_linkToStatic ? noreg : rcx), "only valid assignment");

     assert_different_registers(temp1,        rcx, rdx);

     assert_different_registers(temp2,        rcx, rdx);

     assert_different_registers(temp3,        rcx, rdx);

   }

 */

 #endif

   else {

     assert_different_registers(temp1, temp2, temp3, saved_last_sp_register());  // don't trash lastSP

   }

   assert_different_registers(temp1, temp2, temp3, receiver_reg);

   assert_different_registers(temp1, temp2, temp3, member_reg);

   if (iid == vmIntrinsics::_invokeBasic) {

     // indirect through MH.form.vmentry.vmtarget

     jump_to_lambda_form(_masm, receiver_reg, rbx_method, temp1, 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, 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::vmtarget_offset_in_bytes()));

     Register temp1_recv_klass = temp1;

     if (iid != vmIntrinsics::_linkToStatic) {

       __ verify_oop(receiver_reg);

       if (iid == vmIntrinsics::_linkToSpecial) {

         // Don't actually load the klass; just null-check the receiver.

         __ null_check(receiver_reg);

       } else {

         // load receiver klass itself

         __ null_check(receiver_reg, 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);

       }

       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);

         __ verify_klass_ptr(temp2_defc);

         __ check_klass_subtype(temp1_recv_klass, temp2_defc, temp3, L_ok);

         // 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 trailing argument

     //  temp1_recv_klass - klass of stacked receiver, if needed

     //  rsi/r13 - interpreter linkage (if interpreted)

     //  rcx, rdx, rsi, rdi, r8, r8 - compiler arguments (if compiled)

     Label L_incompatible_class_change_error;

     switch (iid) {

     case vmIntrinsics::_linkToSpecial:

       if (VerifyMethodHandles) {

         verify_ref_kind(_masm, JVM_REF_invokeSpecial, member_reg, temp3);

       }

       __ ld(rbx_method, member_vmtarget);

       break;

     case vmIntrinsics::_linkToStatic:

       if (VerifyMethodHandles) {

         verify_ref_kind(_masm, JVM_REF_invokeStatic, member_reg, temp3);

       }

       __ ld(rbx_method, member_vmtarget);

       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;

       __ ld(temp2_index, member_vmindex);

       if (VerifyMethodHandles) {

         Label L_index_ok;

 //        __ cmpl(temp2_index, 0);

 //        __ jcc(Assembler::greaterEqual, L_index_ok);

         __ slt(AT, R0, temp2_index);

         __ bne(AT, R0, L_index_ok);

         __ nop();

         __ 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, rbx_method);

       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);

       __ verify_klass_ptr(temp3_intf);

       Register rbx_index = rbx_method;

       __ ld(rbx_index, member_vmindex);

       if (VerifyMethodHandles) {

         Label L;

 //        __ cmpl(rbx_index, 0);

 //        __ jcc(Assembler::greaterEqual, L);

         __ slt(AT, R0, rbx_index);

         __ bne(AT, R0, L);

         __ nop();

         __ STOP("invalid vtable index for MH.invokeInterface");

         __ bind(L);

       }

       // given intf, index, and recv klass, dispatch to the implementation method

       __ lookup_interface_method(temp1_recv_klass, temp3_intf,

                                  // note: next two args must be the same:

                                  rbx_index, rbx_method,

                                  temp2,

                                  L_incompatible_class_change_error);

       break;

     }

     default:

       fatal(err_msg_res("unexpected intrinsic %d: %s", iid, vmIntrinsics::name_at(iid)));

       break;

     }

     // Live at this point:

     //   rbx_method

     //   rsi/r13 (if interpreted)

     // After figuring out which concrete method to call, jump into it.

     // Note that this works in the interpreter with no data motion.

     // But the compiled version will require that rcx_recv be shifted out.

     __ verify_method_ptr(rbx_method);

     jump_from_method_handle(_masm, rbx_method, temp1, for_compiler_entry);

     if (iid == vmIntrinsics::_linkToInterface) {

       __ bind(L_incompatible_class_change_error);

 //      __ jump(RuntimeAddress(StubRoutines::throw_IncompatibleClassChangeError_entry()));

       address icce_entry= StubRoutines::throw_IncompatibleClassChangeError_entry();

       __ jmp(icce_entry, relocInfo::runtime_call_type);

       __ nop();

     }

   }

 }

 #ifndef PRODUCT

 void trace_method_handle_stub(const char* adaptername,

                               oop mh,

                               intptr_t* saved_regs,

                               intptr_t* entry_sp) {

   // 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

   const char* mh_reg_name = has_mh ? "rcx_mh" : "rcx";

   tty->print_cr("MH %s %s="PTR_FORMAT" sp="PTR_FORMAT,

                 adaptername, mh_reg_name,

                 (void *)mh, entry_sp);

   if (Verbose) {

     tty->print_cr("Registers:");

     const int saved_regs_count = RegisterImpl::number_of_registers;

     for (int i = 0; i < saved_regs_count; i++) {

       Register r = as_Register(i);

       // The registers are stored in reverse order on the stack (by pusha).

       tty->print("%3s=" PTR_FORMAT, r->name(), saved_regs[((saved_regs_count - 1) - i)]);

       if ((i + 1) % 4 == 0) {

         tty->cr();

       } else {

         tty->print(", ");

       }

     }

     tty->cr();

     {

      // dumping last frame with frame::describe

       JavaThread* p = JavaThread::active();

       ResourceMark rm;

       PRESERVE_EXCEPTION_MARK; // may not be needed by safer and unexpensive here

       FrameValues values;

       // Note: We want to allow trace_method_handle from any call site.

       // While trace_method_handle creates a frame, it may be entered

       // without a PC on the stack top (e.g. not just after a call).

       // Walking that frame could lead to failures due to that invalid PC.

       // => carefully detect that frame when doing the stack walking

       // Current C frame

       frame cur_frame = os::current_frame();

       // Robust search of trace_calling_frame (independant of inlining).

       // Assumes saved_regs comes from a pusha in the trace_calling_frame.

       assert(cur_frame.sp() < saved_regs, "registers not saved on stack ?");

       frame trace_calling_frame = os::get_sender_for_C_frame(&cur_frame);

       while (trace_calling_frame.fp() < saved_regs) {

         trace_calling_frame = os::get_sender_for_C_frame(&trace_calling_frame);

       }

       // safely create a frame and call frame::describe

       intptr_t *dump_sp = trace_calling_frame.sender_sp();

       intptr_t *dump_fp = trace_calling_frame.link();

       bool walkable = has_mh; // whether the traced frame shoud be walkable

       if (walkable) {

         // The previous definition of walkable may have to be refined

         // if new call sites cause the next frame constructor to start

         // failing. Alternatively, frame constructors could be

         // modified to support the current or future non walkable

         // frames (but this is more intrusive and is not considered as

         // part of this RFE, which will instead use a simpler output).

         frame dump_frame = frame(dump_sp, dump_fp);

         dump_frame.describe(values, 1);

       } else {

         // Stack may not be walkable (invalid PC above FP):

         // Add descriptions without building a Java frame to avoid issues

         values.describe(-1, dump_fp, "fp for #1 <not parsed, cannot trust pc>");

         values.describe(-1, dump_sp, "sp for #1");

       }

       values.describe(-1, entry_sp, "raw top of stack");

       tty->print_cr("Stack layout:");

       values.print(p);

     }

     if (has_mh && mh->is_oop()) {

       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();

       }

     }

   }

 }

 // The stub wraps the arguments in a struct on the stack to avoid

 // dealing with the different calling conventions for passing 6

 // arguments.

 struct MethodHandleStubArguments {

   const char* adaptername;

   oopDesc* mh;

   intptr_t* saved_regs;

   intptr_t* entry_sp;

 };

 void trace_method_handle_stub_wrapper(MethodHandleStubArguments* args) {

   trace_method_handle_stub(args->adaptername,

                            args->mh,

                            args->saved_regs,

                            args->entry_sp);

 }

 void MethodHandles::trace_method_handle(MacroAssembler* _masm, const char* adaptername) {

 /*

   if (!TraceMethodHandles)  return;

   BLOCK_COMMENT("trace_method_handle {");

   __ enter();

   __ andptr(rsp, -16); // align stack if needed for FPU state

   __ pusha();

   __ mov(rbx, rsp); // for retreiving saved_regs

   // Note: saved_regs must be in the entered frame for the

   // robust stack walking implemented in trace_method_handle_stub.

   // save FP result, valid at some call sites (adapter_opt_return_float, ...)

   __ increment(rsp, -2 * wordSize);

   if  (UseSSE >= 2) {

     __ movdbl(Address(rsp, 0), xmm0);

   } else if (UseSSE == 1) {

     __ movflt(Address(rsp, 0), xmm0);

   } else {

     __ fst_d(Address(rsp, 0));

   }

   // Incoming state:

   // rcx: method handle

   //

   // To avoid calling convention issues, build a record on the stack

   // and pass the pointer to that instead.

   __ push(rbp);               // entry_sp (with extra align space)

   __ push(rbx);               // pusha saved_regs

   __ push(rcx);               // mh

   __ push(rcx);               // slot for adaptername

   __ movptr(Address(rsp, 0), (intptr_t) adaptername);

   __ super_call_VM_leaf(CAST_FROM_FN_PTR(address, trace_method_handle_stub_wrapper), rsp);

   __ increment(rsp, sizeof(MethodHandleStubArguments));

   if  (UseSSE >= 2) {

     __ movdbl(xmm0, Address(rsp, 0));

   } else if (UseSSE == 1) {

     __ movflt(xmm0, Address(rsp, 0));

   } else {

     __ fld_d(Address(rsp, 0));

   }

   __ increment(rsp, 2 * wordSize);

   __ popa();

   __ leave();

   BLOCK_COMMENT("} trace_method_handle");

 */

 }

 #endif //PRODUCT