Mercurial > jdk8-mips64-public > hotspot / file revision

 /*

  * Copyright (c) 2008, 2012, 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.

  *

  */

 #include "precompiled.hpp"

 #include "interpreter/interpreter.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 ":")

 // Workaround for C++ overloading nastiness on '0' for RegisterOrConstant.

 static RegisterOrConstant constant(int value) {

   return RegisterOrConstant(value);

 }

 void MethodHandles::load_klass_from_Class(MacroAssembler* _masm, Register klass_reg, Register temp_reg, Register temp2_reg) {

   if (VerifyMethodHandles)

     verify_klass(_masm, klass_reg, SystemDictionaryHandles::Class_klass(), temp_reg, temp2_reg,

                  "MH argument is a Class");

   __ load_heap_oop(Address(klass_reg, java_lang_Class::klass_offset_in_bytes()), klass_reg);

 }

 #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_reg, KlassHandle klass,

                                  Register temp_reg, Register temp2_reg,

                                  const char* error_message) {

   oop* klass_addr = klass.raw_value();

   assert(klass_addr >= SystemDictionaryHandles::Object_klass().raw_value() &&

          klass_addr <= SystemDictionaryHandles::Long_klass().raw_value(),

          "must be one of the SystemDictionaryHandles");

   bool did_save = false;

   if (temp_reg == noreg || temp2_reg == noreg) {

     temp_reg = L1;

     temp2_reg = L2;

     __ save_frame_and_mov(0, obj_reg, L0);

     obj_reg = L0;

     did_save = true;

   }

   Label L_ok, L_bad;

   BLOCK_COMMENT("verify_klass {");

   __ verify_oop(obj_reg);

   __ br_null_short(obj_reg, Assembler::pn, L_bad);

   __ load_klass(obj_reg, temp_reg);

   __ set(ExternalAddress(klass_addr), temp2_reg);

   __ ld_ptr(Address(temp2_reg, 0), temp2_reg);

   __ cmp_and_brx_short(temp_reg, temp2_reg, Assembler::equal, Assembler::pt, L_ok);

   intptr_t super_check_offset = klass->super_check_offset();

   __ ld_ptr(Address(temp_reg, super_check_offset), temp_reg);

   __ set(ExternalAddress(klass_addr), temp2_reg);

   __ ld_ptr(Address(temp2_reg, 0), temp2_reg);

   __ cmp_and_brx_short(temp_reg, temp2_reg, Assembler::equal, Assembler::pt, L_ok);

   __ BIND(L_bad);

   if (did_save)  __ restore();

   __ STOP(error_message);

   __ BIND(L_ok);

   if (did_save)  __ restore();

   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 {");

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

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

   __ and3(temp, java_lang_invoke_MemberName::MN_REFERENCE_KIND_MASK,  temp);

   __ cmp_and_br_short(temp, ref_kind, Assembler::equal, Assembler::pt, L);

   { 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 target, Register temp,

                                             bool for_compiler_entry) {

   assert(method == G5_method, "interpreter calling convention");

   __ verify_oop(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.

     __ verify_thread();

     const Address interp_only(G2_thread, JavaThread::interp_only_mode_offset());

     __ ld(interp_only, temp);

     __ cmp_and_br_short(temp, 0, Assembler::zero, Assembler::pt, run_compiled_code);

     __ ld_ptr(G5_method, in_bytes(methodOopDesc::interpreter_entry_offset()), target);

     __ jmp(target, 0);

     __ delayed()->nop();

     __ BIND(run_compiled_code);

     // Note: we could fill some delay slots here, but

     // it doesn't matter, since this is interpreter code.

   }

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

                                                      methodOopDesc::from_interpreted_offset();

   __ ld_ptr(G5_method, in_bytes(entry_offset), target);

   __ jmp(target, 0);

   __ delayed()->nop();

 }

 void MethodHandles::jump_to_lambda_form(MacroAssembler* _masm,

                                         Register recv, Register method_temp,

                                         Register temp2, Register temp3,

                                         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, temp3);

   assert(method_temp == G5_method, "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(Address(recv,        NONZERO(java_lang_invoke_MethodHandle::form_offset_in_bytes())),       method_temp);

   __ verify_oop(method_temp);

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

   __ verify_oop(method_temp);

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

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

   __ verify_oop(method_temp);

   if (VerifyMethodHandles && !for_compiler_entry) {

     // make sure recv is already on stack

     __ load_sized_value(Address(method_temp, methodOopDesc::size_of_parameters_offset()),

                         temp2,

                         sizeof(u2), /*is_signed*/ false);

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

     Label L;

     __ ld_ptr(__ argument_address(temp2, temp2, -1), temp2);

     __ cmp_and_br_short(temp2, recv, Assembler::equal, Assembler::pt, L);

     __ STOP("receiver not on stack");

     __ BIND(L);

   }

   jump_from_method_handle(_masm, method_temp, temp2, temp3, 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.

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

     return NULL;

   }

   // I5_savedSP/O5_savedSP: sender SP (must preserve; see prepare_to_jump_from_interpreted)

   // G5_method:  methodOop

   // G4 (Gargs): incoming argument list (must preserve)

   // O0: used as temp to hold mh or receiver

   // O1, O4: garbage temps, blown away

   Register O1_scratch    = O1;

   Register O4_param_size = O4;   // size of parameters

   address code_start = __ pc();

   // here's where control starts out:

   __ align(CodeEntryAlignment);

   address entry_point = __ pc();

   if (VerifyMethodHandles) {

     Label L;

     BLOCK_COMMENT("verify_intrinsic_id {");

     __ ldub(Address(G5_method, methodOopDesc::intrinsic_id_offset_in_bytes()), O1_scratch);

     __ cmp_and_br_short(O1_scratch, (int) iid, Assembler::equal, Assembler::pt, 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 methodOop::intrinsic_id");

     }

     __ STOP("bad methodOop::intrinsic_id");

     __ bind(L);

     BLOCK_COMMENT("} verify_intrinsic_id");

   }

   // First task:  Find out how big the argument list is.

   Address O4_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)) {

     __ load_sized_value(Address(G5_method, methodOopDesc::size_of_parameters_offset()),

                         O4_param_size,

                         sizeof(u2), /*is_signed*/ false);

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

     O4_first_arg_addr = __ argument_address(O4_param_size, O4_param_size, -1);

   } else {

     DEBUG_ONLY(O4_param_size = noreg);

   }

   Register O0_mh = noreg;

   if (!is_signature_polymorphic_static(iid)) {

     __ ld_ptr(O4_first_arg_addr, O0_mh = O0);

     DEBUG_ONLY(O4_param_size = noreg);

   }

   // O4_first_arg_addr is live!

   if (TraceMethodHandles) {

     const char* name = vmIntrinsics::name_at(iid);

     if (*name == '_')  name += 1;

     const size_t len = strlen(name) + 50;

     char* qname = NEW_C_HEAP_ARRAY(char, len, mtInternal);

     const char* suffix = "";

     if (vmIntrinsics::method_for(iid) == NULL ||

         !vmIntrinsics::method_for(iid)->access_flags().is_public()) {

       if (is_signature_polymorphic_static(iid))

         suffix = "/static";

       else

         suffix = "/private";

     }

     jio_snprintf(qname, len, "MethodHandle::interpreter_entry::%s%s", name, suffix);

     if (O0_mh != noreg)

       __ mov(O0_mh, G3_method_handle);  // make stub happy

     trace_method_handle(_masm, qname);

   }

   if (iid == vmIntrinsics::_invokeBasic) {

     generate_method_handle_dispatch(_masm, iid, O0_mh, noreg, not_for_compiler_entry);

   } else {

     // Adjust argument list by popping the trailing MemberName argument.

     Register O0_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_ptr(O4_first_arg_addr, O0_recv = O0);

       DEBUG_ONLY(O4_param_size = noreg);

     }

     Register G5_member = G5_method;  // MemberName ptr; incoming method ptr is dead now

     __ ld_ptr(__ argument_address(constant(0)), G5_member);

     __ add(Gargs, Interpreter::stackElementSize, Gargs);

     generate_method_handle_dispatch(_masm, iid, O0_recv, G5_member, not_for_compiler_entry);

   }

   if (PrintMethodHandleStubs) {

     address code_end = __ pc();

     tty->print_cr("--------");

     tty->print_cr("method handle interpreter entry for %s", vmIntrinsics::name_at(iid));

     Disassembler::decode(code_start, code_end);

     tty->cr();

   }

   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");

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

   Register temp1 = (for_compiler_entry ? G1_scratch : O1);

   Register temp2 = (for_compiler_entry ? G4_scratch : O4);

   Register temp3 = G3_scratch;

   Register temp4 = (for_compiler_entry ? noreg      : O2);

   if (for_compiler_entry) {

     assert(receiver_reg == (iid == vmIntrinsics::_linkToStatic ? noreg : O0), "only valid assignment");

     assert_different_registers(temp1,      O0, O1, O2, O3, O4, O5);

     assert_different_registers(temp2,      O0, O1, O2, O3, O4, O5);

     assert_different_registers(temp3,      O0, O1, O2, O3, O4, O5);

     assert_different_registers(temp4,      O0, O1, O2, O3, O4, O5);

   }

   if (receiver_reg != noreg)  assert_different_registers(temp1, temp2, temp3, temp4, receiver_reg);

   if (member_reg   != noreg)  assert_different_registers(temp1, temp2, temp3, temp4, member_reg);

   if (!for_compiler_entry)    assert_different_registers(temp1, temp2, temp3, temp4, O5_savedSP);  // don't trash lastSP

   if (iid == vmIntrinsics::_invokeBasic) {

     // indirect through MH.form.vmentry.vmtarget

     jump_to_lambda_form(_masm, receiver_reg, G5_method, temp2, 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, SystemDictionaryHandles::MemberName_klass(),

                    temp1, temp2,

                    "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(receiver_reg, temp1_recv_klass);

         __ verify_oop(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(receiver_reg, temp1_recv_klass);

         __ verify_oop(temp1_recv_klass);

       }

       if (VerifyMethodHandles && iid != vmIntrinsics::_linkToInterface) {

         Label L_ok;

         Register temp2_defc = temp2;

         __ load_heap_oop(member_clazz, temp2_defc);

         load_klass_from_Class(_masm, temp2_defc, temp3, temp4);

         __ verify_oop(temp2_defc);

         __ check_klass_subtype(temp1_recv_klass, temp2_defc, temp3, temp4, 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

     //  O5_savedSP - interpreter linkage (if interpreted)

     //  O0..O7,G1,G4 - compiler arguments (if compiled)

     bool method_is_live = false;

     switch (iid) {

     case vmIntrinsics::_linkToSpecial:

       if (VerifyMethodHandles) {

         verify_ref_kind(_masm, JVM_REF_invokeSpecial, member_reg, temp3);

       }

       __ load_heap_oop(member_vmtarget, G5_method);

       method_is_live = true;

       break;

     case vmIntrinsics::_linkToStatic:

       if (VerifyMethodHandles) {

         verify_ref_kind(_masm, JVM_REF_invokeStatic, member_reg, temp3);

       }

       __ load_heap_oop(member_vmtarget, G5_method);

       method_is_live = true;

       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_ptr(member_vmindex, temp2_index);

       if (VerifyMethodHandles) {

         Label L_index_ok;

         __ cmp_and_br_short(temp2_index, (int) 0, Assembler::greaterEqual, Assembler::pn, L_index_ok);

         __ 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 methodOop & entry point

       __ lookup_virtual_method(temp1_recv_klass, temp2_index, G5_method);

       method_is_live = true;

       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(member_clazz, temp3_intf);

       load_klass_from_Class(_masm, temp3_intf, temp2, temp4);

       __ verify_oop(temp3_intf);

       Register G5_index = G5_method;

       __ ld_ptr(member_vmindex, G5_index);

       if (VerifyMethodHandles) {

         Label L;

         __ cmp_and_br_short(G5_index, 0, Assembler::greaterEqual, Assembler::pt, L);

         __ 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;

       Register no_sethi_temp = noreg;

       __ lookup_interface_method(temp1_recv_klass, temp3_intf,

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

                                  G5_index, G5_method,

                                  temp2, no_sethi_temp,

                                  L_no_such_interface);

       __ verify_oop(G5_method);

       jump_from_method_handle(_masm, G5_method, temp2, temp3, for_compiler_entry);

       __ bind(L_no_such_interface);

       AddressLiteral icce(StubRoutines::throw_IncompatibleClassChangeError_entry());

       __ jump_to(icce, temp3);

       __ delayed()->nop();

       break;

     }

     default:

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

       break;

     }

     if (method_is_live) {

       // live at this point:  G5_method, O5_savedSP (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_oop(G5_method);

       jump_from_method_handle(_masm, G5_method, temp1, temp3, for_compiler_entry);

     }

   }

 }

 #ifndef PRODUCT

 void trace_method_handle_stub(const char* adaptername,

                               oopDesc* mh,

                               intptr_t* saved_sp,

                               intptr_t* args,

                               intptr_t* tracing_fp) {

   bool has_mh = (strstr(adaptername, "/static") == NULL &&

                  strstr(adaptername, "linkTo") == NULL);    // static linkers don't have MH

   const char* mh_reg_name = has_mh ? "G3_mh" : "G3";

   tty->print_cr("MH %s %s="INTPTR_FORMAT " saved_sp=" INTPTR_FORMAT " args=" INTPTR_FORMAT,

                 adaptername, mh_reg_name,

                 (intptr_t) mh, saved_sp, args);

   if (Verbose) {

     // 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 valid return PC in O7 (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

     // walk up to the right frame using the "tracing_fp" argument

     intptr_t* cur_sp = StubRoutines::Sparc::flush_callers_register_windows_func()();

     frame cur_frame(cur_sp, frame::unpatchable, NULL);

     while (cur_frame.fp() != (intptr_t *)(STACK_BIAS+(uintptr_t)tracing_fp)) {

       cur_frame = os::get_sender_for_C_frame(&cur_frame);

     }

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

     intptr_t *dump_sp = cur_frame.sender_sp();

     intptr_t *dump_fp = cur_frame.link();

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

     // the sender for cur_frame is the caller of trace_method_handle

     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,

                                cur_frame.sp(), // younger_sp

                                false); // no adaptation

       dump_frame.describe(values, 1);

     } else {

       // Robust dump for frames which cannot be constructed from sp/younger_sp

       // 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");

     }

     bool has_args = has_mh; // whether Gargs is meaningful

     // mark args, if seems valid (may not be valid for some adapters)

     if (has_args) {

       if ((args >= dump_sp) && (args < dump_fp)) {

         values.describe(-1, args, "*G4_args");

       }

     }

     // mark saved_sp, if seems valid (may not be valid for some adapters)

     intptr_t *unbiased_sp = (intptr_t *)(STACK_BIAS+(uintptr_t)saved_sp);

     const int ARG_LIMIT = 255, SLOP = 45, UNREASONABLE_STACK_MOVE = (ARG_LIMIT + SLOP);

     if ((unbiased_sp >= dump_sp - UNREASONABLE_STACK_MOVE) && (unbiased_sp < dump_fp)) {

       values.describe(-1, unbiased_sp, "*saved_sp+STACK_BIAS");

     }

     // Note: the unextended_sp may not be correct

     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();

       }

     }

   }

 }

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

   if (!TraceMethodHandles)  return;

   BLOCK_COMMENT("trace_method_handle {");

   // save: Gargs, O5_savedSP

   __ save_frame(16); // need space for saving required FPU state

   __ set((intptr_t) adaptername, O0);

   __ mov(G3_method_handle, O1);

   __ mov(I5_savedSP, O2);

   __ mov(Gargs, O3);

   __ mov(I6, O4); // frame identifier for safe stack walking

   // Save scratched registers that might be needed. Robustness is more

   // important than optimizing the saves for this debug only code.

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

   Address d_save(FP, -sizeof(jdouble) + STACK_BIAS);

   __ stf(FloatRegisterImpl::D, Ftos_d, d_save);

   // Safely save all globals but G2 (handled by call_VM_leaf) and G7

   // (OS reserved).

   __ mov(G3_method_handle, L3);

   __ mov(Gargs, L4);

   __ mov(G5_method_type, L5);

   __ mov(G6, L6);

   __ mov(G1, L1);

   __ call_VM_leaf(L2 /* for G2 */, CAST_FROM_FN_PTR(address, trace_method_handle_stub));

   __ mov(L3, G3_method_handle);

   __ mov(L4, Gargs);

   __ mov(L5, G5_method_type);

   __ mov(L6, G6);

   __ mov(L1, G1);

   __ ldf(FloatRegisterImpl::D, d_save, Ftos_d);

   __ restore();

   BLOCK_COMMENT("} trace_method_handle");

 }

 #endif // PRODUCT