1 /*
   2  * Copyright (c) 1997, 2018, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "jvm.h"
  27 #include "asm/macroAssembler.hpp"
  28 #include "compiler/disassembler.hpp"
  29 #include "classfile/javaClasses.inline.hpp"
  30 #include "interpreter/interpreter.hpp"
  31 #include "interpreter/interpreterRuntime.hpp"
  32 #include "memory/allocation.inline.hpp"
  33 #include "memory/resourceArea.hpp"
  34 #include "prims/methodHandles.hpp"
  35 #include "runtime/flags/flagSetting.hpp"
  36 #include "runtime/frame.inline.hpp"
  37 #include "utilities/preserveException.hpp"
  38 
  39 #define __ Disassembler::hook<MacroAssembler>(__FILE__, __LINE__, _masm)->
  40 
  41 #ifdef PRODUCT
  42 #define BLOCK_COMMENT(str) /* nothing */
  43 #define STOP(error) stop(error)
  44 #else
  45 #define BLOCK_COMMENT(str) __ block_comment(str)
  46 #define STOP(error) block_comment(error); __ stop(error)
  47 #endif
  48 
  49 #define BIND(label) bind(label); BLOCK_COMMENT(#label ":")
  50 
  51 void MethodHandles::load_klass_from_Class(MacroAssembler* _masm, Register klass_reg) {
  52   if (VerifyMethodHandles)
  53     verify_klass(_masm, klass_reg, SystemDictionary::WK_KLASS_ENUM_NAME(java_lang_Class),
  54                  "MH argument is a Class");
  55   __ movptr(klass_reg, Address(klass_reg, java_lang_Class::klass_offset_in_bytes()));
  56 }
  57 
  58 #ifdef ASSERT
  59 static int check_nonzero(const char* xname, int x) {
  60   assert(x != 0, "%s should be nonzero", xname);
  61   return x;
  62 }
  63 #define NONZERO(x) check_nonzero(#x, x)
  64 #else //ASSERT
  65 #define NONZERO(x) (x)
  66 #endif //ASSERT
  67 
  68 #ifdef ASSERT
  69 void MethodHandles::verify_klass(MacroAssembler* _masm,
  70                                  Register obj, SystemDictionary::WKID klass_id,
  71                                  const char* error_message) {
  72   InstanceKlass** klass_addr = SystemDictionary::well_known_klass_addr(klass_id);
  73   Klass* klass = SystemDictionary::well_known_klass(klass_id);
  74   Register temp = rdi;
  75   Register temp2 = noreg;
  76   LP64_ONLY(temp2 = rscratch1);  // used by MacroAssembler::cmpptr
  77   Label L_ok, L_bad;
  78   BLOCK_COMMENT("verify_klass {");
  79   __ verify_oop(obj);
  80   __ testptr(obj, obj);
  81   __ jcc(Assembler::zero, L_bad);
  82   __ push(temp); if (temp2 != noreg)  __ push(temp2);
  83 #define UNPUSH { if (temp2 != noreg)  __ pop(temp2);  __ pop(temp); }
  84   __ load_klass(temp, obj);
  85   __ cmpptr(temp, ExternalAddress((address) klass_addr));
  86   __ jcc(Assembler::equal, L_ok);
  87   intptr_t super_check_offset = klass->super_check_offset();
  88   __ movptr(temp, Address(temp, super_check_offset));
  89   __ cmpptr(temp, ExternalAddress((address) klass_addr));
  90   __ jcc(Assembler::equal, L_ok);
  91   UNPUSH;
  92   __ bind(L_bad);
  93   __ STOP(error_message);
  94   __ BIND(L_ok);
  95   UNPUSH;
  96   BLOCK_COMMENT("} verify_klass");
  97 }
  98 
  99 void MethodHandles::verify_ref_kind(MacroAssembler* _masm, int ref_kind, Register member_reg, Register temp) {
 100   Label L;
 101   BLOCK_COMMENT("verify_ref_kind {");
 102   __ movl(temp, Address(member_reg, NONZERO(java_lang_invoke_MemberName::flags_offset_in_bytes())));
 103   __ shrl(temp, java_lang_invoke_MemberName::MN_REFERENCE_KIND_SHIFT);
 104   __ andl(temp, java_lang_invoke_MemberName::MN_REFERENCE_KIND_MASK);
 105   __ cmpl(temp, ref_kind);
 106   __ jcc(Assembler::equal, L);
 107   { char* buf = NEW_C_HEAP_ARRAY(char, 100, mtInternal);
 108     jio_snprintf(buf, 100, "verify_ref_kind expected %x", ref_kind);
 109     if (ref_kind == JVM_REF_invokeVirtual ||
 110         ref_kind == JVM_REF_invokeSpecial)
 111       // could do this for all ref_kinds, but would explode assembly code size
 112       trace_method_handle(_masm, buf);
 113     __ STOP(buf);
 114   }
 115   BLOCK_COMMENT("} verify_ref_kind");
 116   __ bind(L);
 117 }
 118 
 119 #endif //ASSERT
 120 
 121 void MethodHandles::jump_from_method_handle(MacroAssembler* _masm, Register method, Register temp,
 122                                             bool for_compiler_entry) {
 123   assert(method == rbx, "interpreter calling convention");
 124 
 125    Label L_no_such_method;
 126    __ testptr(rbx, rbx);
 127    __ jcc(Assembler::zero, L_no_such_method);
 128 
 129   __ verify_method_ptr(method);
 130 
 131   if (!for_compiler_entry && JvmtiExport::can_post_interpreter_events()) {
 132     Label run_compiled_code;
 133     // JVMTI events, such as single-stepping, are implemented partly by avoiding running
 134     // compiled code in threads for which the event is enabled.  Check here for
 135     // interp_only_mode if these events CAN be enabled.
 136 #ifdef _LP64
 137     Register rthread = r15_thread;
 138 #else
 139     Register rthread = temp;
 140     __ get_thread(rthread);
 141 #endif
 142     // interp_only is an int, on little endian it is sufficient to test the byte only
 143     // Is a cmpl faster?
 144     __ cmpb(Address(rthread, JavaThread::interp_only_mode_offset()), 0);
 145     __ jccb(Assembler::zero, run_compiled_code);
 146     __ jmp(Address(method, Method::interpreter_entry_offset()));
 147     __ BIND(run_compiled_code);
 148   }
 149 
 150   const ByteSize entry_offset = for_compiler_entry ? Method::from_compiled_offset() :
 151                                                      Method::from_interpreted_offset();
 152   __ jmp(Address(method, entry_offset));
 153 
 154   __ bind(L_no_such_method);
 155   __ jump(RuntimeAddress(StubRoutines::throw_AbstractMethodError_entry()));
 156 }
 157 
 158 void MethodHandles::jump_to_lambda_form(MacroAssembler* _masm,
 159                                         Register recv, Register method_temp,
 160                                         Register temp2,
 161                                         bool for_compiler_entry) {
 162   BLOCK_COMMENT("jump_to_lambda_form {");
 163   // This is the initial entry point of a lazy method handle.
 164   // After type checking, it picks up the invoker from the LambdaForm.
 165   assert_different_registers(recv, method_temp, temp2);
 166   assert(recv != noreg, "required register");
 167   assert(method_temp == rbx, "required register for loading method");
 168 
 169   //NOT_PRODUCT({ FlagSetting fs(TraceMethodHandles, true); trace_method_handle(_masm, "LZMH"); });
 170 
 171   // Load the invoker, as MH -> MH.form -> LF.vmentry
 172   __ verify_oop(recv);
 173   __ load_heap_oop(method_temp, Address(recv, NONZERO(java_lang_invoke_MethodHandle::form_offset_in_bytes())), temp2);
 174   __ verify_oop(method_temp);
 175   __ load_heap_oop(method_temp, Address(method_temp, NONZERO(java_lang_invoke_LambdaForm::vmentry_offset_in_bytes())), temp2);
 176   __ verify_oop(method_temp);
 177   __ load_heap_oop(method_temp, Address(method_temp, NONZERO(java_lang_invoke_MemberName::method_offset_in_bytes())), temp2);
 178   __ verify_oop(method_temp);
 179   __ access_load_at(T_ADDRESS, IN_HEAP, method_temp,
 180                     Address(method_temp, NONZERO(java_lang_invoke_ResolvedMethodName::vmtarget_offset_in_bytes())),
 181                     noreg, noreg);
 182 
 183   if (VerifyMethodHandles && !for_compiler_entry) {
 184     // make sure recv is already on stack
 185     __ movptr(temp2, Address(method_temp, Method::const_offset()));
 186     __ load_sized_value(temp2,
 187                         Address(temp2, ConstMethod::size_of_parameters_offset()),
 188                         sizeof(u2), /*is_signed*/ false);
 189     // assert(sizeof(u2) == sizeof(Method::_size_of_parameters), "");
 190     Label L;
 191     __ cmpoop(recv, __ argument_address(temp2, -1));
 192     __ jcc(Assembler::equal, L);
 193     __ movptr(rax, __ argument_address(temp2, -1));
 194     __ STOP("receiver not on stack");
 195     __ BIND(L);
 196   }
 197 
 198   jump_from_method_handle(_masm, method_temp, temp2, for_compiler_entry);
 199   BLOCK_COMMENT("} jump_to_lambda_form");
 200 }
 201 
 202 
 203 // Code generation
 204 address MethodHandles::generate_method_handle_interpreter_entry(MacroAssembler* _masm,
 205                                                                 vmIntrinsics::ID iid) {
 206   const bool not_for_compiler_entry = false;  // this is the interpreter entry
 207   assert(is_signature_polymorphic(iid), "expected invoke iid");
 208   if (iid == vmIntrinsics::_invokeGeneric ||
 209       iid == vmIntrinsics::_compiledLambdaForm) {
 210     // Perhaps surprisingly, the symbolic references visible to Java are not directly used.
 211     // They are linked to Java-generated adapters via MethodHandleNatives.linkMethod.
 212     // They all allow an appendix argument.
 213     __ hlt();           // empty stubs make SG sick
 214     return NULL;
 215   }
 216 
 217   // rsi/r13: sender SP (must preserve; see prepare_to_jump_from_interpreted)
 218   // rbx: Method*
 219   // rdx: argument locator (parameter slot count, added to rsp)
 220   // rcx: used as temp to hold mh or receiver
 221   // rax, rdi: garbage temps, blown away
 222   Register rdx_argp   = rdx;   // argument list ptr, live on error paths
 223   Register rax_temp   = rax;
 224   Register rcx_mh     = rcx;   // MH receiver; dies quickly and is recycled
 225   Register rbx_method = rbx;   // eventual target of this invocation
 226 
 227   // here's where control starts out:
 228   __ align(CodeEntryAlignment);
 229   address entry_point = __ pc();
 230 
 231   if (VerifyMethodHandles) {
 232     assert(Method::intrinsic_id_size_in_bytes() == 2, "assuming Method::_intrinsic_id is u2");
 233 
 234     Label L;
 235     BLOCK_COMMENT("verify_intrinsic_id {");
 236     __ cmpw(Address(rbx_method, Method::intrinsic_id_offset_in_bytes()), (int) iid);
 237     __ jcc(Assembler::equal, L);
 238     if (iid == vmIntrinsics::_linkToVirtual ||
 239         iid == vmIntrinsics::_linkToSpecial) {
 240       // could do this for all kinds, but would explode assembly code size
 241       trace_method_handle(_masm, "bad Method*::intrinsic_id");
 242     }
 243     __ STOP("bad Method*::intrinsic_id");
 244     __ bind(L);
 245     BLOCK_COMMENT("} verify_intrinsic_id");
 246   }
 247 
 248   // First task:  Find out how big the argument list is.
 249   Address rdx_first_arg_addr;
 250   int ref_kind = signature_polymorphic_intrinsic_ref_kind(iid);
 251   assert(ref_kind != 0 || iid == vmIntrinsics::_invokeBasic, "must be _invokeBasic or a linkTo intrinsic");
 252   if (ref_kind == 0 || MethodHandles::ref_kind_has_receiver(ref_kind)) {
 253     __ movptr(rdx_argp, Address(rbx_method, Method::const_offset()));
 254     __ load_sized_value(rdx_argp,
 255                         Address(rdx_argp, ConstMethod::size_of_parameters_offset()),
 256                         sizeof(u2), /*is_signed*/ false);
 257     // assert(sizeof(u2) == sizeof(Method::_size_of_parameters), "");
 258     rdx_first_arg_addr = __ argument_address(rdx_argp, -1);
 259   } else {
 260     DEBUG_ONLY(rdx_argp = noreg);
 261   }
 262 
 263   if (!is_signature_polymorphic_static(iid)) {
 264     __ movptr(rcx_mh, rdx_first_arg_addr);
 265     DEBUG_ONLY(rdx_argp = noreg);
 266   }
 267 
 268   // rdx_first_arg_addr is live!
 269 
 270   trace_method_handle_interpreter_entry(_masm, iid);
 271 
 272   if (iid == vmIntrinsics::_invokeBasic) {
 273     generate_method_handle_dispatch(_masm, iid, rcx_mh, noreg, not_for_compiler_entry);
 274 
 275   } else {
 276     // Adjust argument list by popping the trailing MemberName argument.
 277     Register rcx_recv = noreg;
 278     if (MethodHandles::ref_kind_has_receiver(ref_kind)) {
 279       // Load the receiver (not the MH; the actual MemberName's receiver) up from the interpreter stack.
 280       __ movptr(rcx_recv = rcx, rdx_first_arg_addr);
 281     }
 282     DEBUG_ONLY(rdx_argp = noreg);
 283     Register rbx_member = rbx_method;  // MemberName ptr; incoming method ptr is dead now
 284     __ pop(rax_temp);           // return address
 285     __ pop(rbx_member);         // extract last argument
 286     __ push(rax_temp);          // re-push return address
 287     generate_method_handle_dispatch(_masm, iid, rcx_recv, rbx_member, not_for_compiler_entry);
 288   }
 289 
 290   return entry_point;
 291 }
 292 
 293 void MethodHandles::generate_method_handle_dispatch(MacroAssembler* _masm,
 294                                                     vmIntrinsics::ID iid,
 295                                                     Register receiver_reg,
 296                                                     Register member_reg,
 297                                                     bool for_compiler_entry) {
 298   assert(is_signature_polymorphic(iid), "expected invoke iid");
 299   Register rbx_method = rbx;   // eventual target of this invocation
 300   // temps used in this code are not used in *either* compiled or interpreted calling sequences
 301 #ifdef _LP64
 302   Register temp1 = rscratch1;
 303   Register temp2 = rscratch2;
 304   Register temp3 = rax;
 305   if (for_compiler_entry) {
 306     assert(receiver_reg == (iid == vmIntrinsics::_linkToStatic ? noreg : j_rarg0), "only valid assignment");
 307     assert_different_registers(temp1,        j_rarg0, j_rarg1, j_rarg2, j_rarg3, j_rarg4, j_rarg5);
 308     assert_different_registers(temp2,        j_rarg0, j_rarg1, j_rarg2, j_rarg3, j_rarg4, j_rarg5);
 309     assert_different_registers(temp3,        j_rarg0, j_rarg1, j_rarg2, j_rarg3, j_rarg4, j_rarg5);
 310   }
 311 #else
 312   Register temp1 = (for_compiler_entry ? rsi : rdx);
 313   Register temp2 = rdi;
 314   Register temp3 = rax;
 315   if (for_compiler_entry) {
 316     assert(receiver_reg == (iid == vmIntrinsics::_linkToStatic ? noreg : rcx), "only valid assignment");
 317     assert_different_registers(temp1,        rcx, rdx);
 318     assert_different_registers(temp2,        rcx, rdx);
 319     assert_different_registers(temp3,        rcx, rdx);
 320   }
 321 #endif
 322   else {
 323     assert_different_registers(temp1, temp2, temp3, saved_last_sp_register());  // don't trash lastSP
 324   }
 325   assert_different_registers(temp1, temp2, temp3, receiver_reg);
 326   assert_different_registers(temp1, temp2, temp3, member_reg);
 327 
 328   if (iid == vmIntrinsics::_invokeBasic) {
 329     // indirect through MH.form.vmentry.vmtarget
 330     jump_to_lambda_form(_masm, receiver_reg, rbx_method, temp1, for_compiler_entry);
 331 
 332   } else {
 333     // The method is a member invoker used by direct method handles.
 334     if (VerifyMethodHandles) {
 335       // make sure the trailing argument really is a MemberName (caller responsibility)
 336       verify_klass(_masm, member_reg, SystemDictionary::WK_KLASS_ENUM_NAME(java_lang_invoke_MemberName),
 337                    "MemberName required for invokeVirtual etc.");
 338     }
 339 
 340     Address member_clazz(    member_reg, NONZERO(java_lang_invoke_MemberName::clazz_offset_in_bytes()));
 341     Address member_vmindex(  member_reg, NONZERO(java_lang_invoke_MemberName::vmindex_offset_in_bytes()));
 342     Address member_vmtarget( member_reg, NONZERO(java_lang_invoke_MemberName::method_offset_in_bytes()));
 343     Address vmtarget_method( rbx_method, NONZERO(java_lang_invoke_ResolvedMethodName::vmtarget_offset_in_bytes()));
 344 
 345     Register temp1_recv_klass = temp1;
 346     if (iid != vmIntrinsics::_linkToStatic) {
 347       __ verify_oop(receiver_reg);
 348       if (iid == vmIntrinsics::_linkToSpecial) {
 349         // Don't actually load the klass; just null-check the receiver.
 350         __ null_check(receiver_reg);
 351       } else {
 352         // load receiver klass itself
 353         __ null_check(receiver_reg, oopDesc::klass_offset_in_bytes());
 354         __ load_klass(temp1_recv_klass, receiver_reg);
 355         __ verify_klass_ptr(temp1_recv_klass);
 356       }
 357       BLOCK_COMMENT("check_receiver {");
 358       // The receiver for the MemberName must be in receiver_reg.
 359       // Check the receiver against the MemberName.clazz
 360       if (VerifyMethodHandles && iid == vmIntrinsics::_linkToSpecial) {
 361         // Did not load it above...
 362         __ load_klass(temp1_recv_klass, receiver_reg);
 363         __ verify_klass_ptr(temp1_recv_klass);
 364       }
 365       if (VerifyMethodHandles && iid != vmIntrinsics::_linkToInterface) {
 366         Label L_ok;
 367         Register temp2_defc = temp2;
 368         __ load_heap_oop(temp2_defc, member_clazz, temp3);
 369         load_klass_from_Class(_masm, temp2_defc);
 370         __ verify_klass_ptr(temp2_defc);
 371         __ check_klass_subtype(temp1_recv_klass, temp2_defc, temp3, L_ok);
 372         // If we get here, the type check failed!
 373         __ STOP("receiver class disagrees with MemberName.clazz");
 374         __ bind(L_ok);
 375       }
 376       BLOCK_COMMENT("} check_receiver");
 377     }
 378     if (iid == vmIntrinsics::_linkToSpecial ||
 379         iid == vmIntrinsics::_linkToStatic) {
 380       DEBUG_ONLY(temp1_recv_klass = noreg);  // these guys didn't load the recv_klass
 381     }
 382 
 383     // Live registers at this point:
 384     //  member_reg - MemberName that was the trailing argument
 385     //  temp1_recv_klass - klass of stacked receiver, if needed
 386     //  rsi/r13 - interpreter linkage (if interpreted)
 387     //  rcx, rdx, rsi, rdi, r8 - compiler arguments (if compiled)
 388 
 389     Label L_incompatible_class_change_error;
 390     switch (iid) {
 391     case vmIntrinsics::_linkToSpecial:
 392       if (VerifyMethodHandles) {
 393         verify_ref_kind(_masm, JVM_REF_invokeSpecial, member_reg, temp3);
 394       }
 395       __ load_heap_oop(rbx_method, member_vmtarget);
 396       __ access_load_at(T_ADDRESS, IN_HEAP, rbx_method, vmtarget_method, noreg, noreg);
 397       break;
 398 
 399     case vmIntrinsics::_linkToStatic:
 400       if (VerifyMethodHandles) {
 401         verify_ref_kind(_masm, JVM_REF_invokeStatic, member_reg, temp3);
 402       }
 403       __ load_heap_oop(rbx_method, member_vmtarget);
 404       __ access_load_at(T_ADDRESS, IN_HEAP, rbx_method, vmtarget_method, noreg, noreg);
 405       break;
 406 
 407     case vmIntrinsics::_linkToVirtual:
 408     {
 409       // same as TemplateTable::invokevirtual,
 410       // minus the CP setup and profiling:
 411 
 412       if (VerifyMethodHandles) {
 413         verify_ref_kind(_masm, JVM_REF_invokeVirtual, member_reg, temp3);
 414       }
 415 
 416       // pick out the vtable index from the MemberName, and then we can discard it:
 417       Register temp2_index = temp2;
 418       __ access_load_at(T_ADDRESS, IN_HEAP, temp2_index, member_vmindex, noreg, noreg);
 419 
 420       if (VerifyMethodHandles) {
 421         Label L_index_ok;
 422         __ cmpl(temp2_index, 0);
 423         __ jcc(Assembler::greaterEqual, L_index_ok);
 424         __ STOP("no virtual index");
 425         __ BIND(L_index_ok);
 426       }
 427 
 428       // Note:  The verifier invariants allow us to ignore MemberName.clazz and vmtarget
 429       // at this point.  And VerifyMethodHandles has already checked clazz, if needed.
 430 
 431       // get target Method* & entry point
 432       __ lookup_virtual_method(temp1_recv_klass, temp2_index, rbx_method);
 433       break;
 434     }
 435 
 436     case vmIntrinsics::_linkToInterface:
 437     {
 438       // same as TemplateTable::invokeinterface
 439       // (minus the CP setup and profiling, with different argument motion)
 440       if (VerifyMethodHandles) {
 441         verify_ref_kind(_masm, JVM_REF_invokeInterface, member_reg, temp3);
 442       }
 443 
 444       Register temp3_intf = temp3;
 445       __ load_heap_oop(temp3_intf, member_clazz);
 446       load_klass_from_Class(_masm, temp3_intf);
 447       __ verify_klass_ptr(temp3_intf);
 448 
 449       Register rbx_index = rbx_method;
 450       __ access_load_at(T_ADDRESS, IN_HEAP, rbx_index, member_vmindex, noreg, noreg);
 451       if (VerifyMethodHandles) {
 452         Label L;
 453         __ cmpl(rbx_index, 0);
 454         __ jcc(Assembler::greaterEqual, L);
 455         __ STOP("invalid vtable index for MH.invokeInterface");
 456         __ bind(L);
 457       }
 458 
 459       // given intf, index, and recv klass, dispatch to the implementation method
 460       __ lookup_interface_method(temp1_recv_klass, temp3_intf,
 461                                  // note: next two args must be the same:
 462                                  rbx_index, rbx_method,
 463                                  temp2,
 464                                  L_incompatible_class_change_error);
 465       break;
 466     }
 467 
 468     default:
 469       fatal("unexpected intrinsic %d: %s", iid, vmIntrinsics::name_at(iid));
 470       break;
 471     }
 472 
 473     // Live at this point:
 474     //   rbx_method
 475     //   rsi/r13 (if interpreted)
 476 
 477     // After figuring out which concrete method to call, jump into it.
 478     // Note that this works in the interpreter with no data motion.
 479     // But the compiled version will require that rcx_recv be shifted out.
 480     __ verify_method_ptr(rbx_method);
 481     jump_from_method_handle(_masm, rbx_method, temp1, for_compiler_entry);
 482 
 483     if (iid == vmIntrinsics::_linkToInterface) {
 484       __ bind(L_incompatible_class_change_error);
 485       __ jump(RuntimeAddress(StubRoutines::throw_IncompatibleClassChangeError_entry()));
 486     }
 487   }
 488 }
 489 
 490 #ifndef PRODUCT
 491 void trace_method_handle_stub(const char* adaptername,
 492                               oop mh,
 493                               intptr_t* saved_regs,
 494                               intptr_t* entry_sp) {
 495   // called as a leaf from native code: do not block the JVM!
 496   bool has_mh = (strstr(adaptername, "/static") == NULL &&
 497                  strstr(adaptername, "linkTo") == NULL);    // static linkers don't have MH
 498   const char* mh_reg_name = has_mh ? "rcx_mh" : "rcx";
 499   tty->print_cr("MH %s %s=" PTR_FORMAT " sp=" PTR_FORMAT,
 500                 adaptername, mh_reg_name,
 501                 p2i(mh), p2i(entry_sp));
 502 
 503   if (Verbose) {
 504     tty->print_cr("Registers:");
 505     const int saved_regs_count = RegisterImpl::number_of_registers;
 506     for (int i = 0; i < saved_regs_count; i++) {
 507       Register r = as_Register(i);
 508       // The registers are stored in reverse order on the stack (by pusha).
 509       tty->print("%3s=" PTR_FORMAT, r->name(), saved_regs[((saved_regs_count - 1) - i)]);
 510       if ((i + 1) % 4 == 0) {
 511         tty->cr();
 512       } else {
 513         tty->print(", ");
 514       }
 515     }
 516     tty->cr();
 517 
 518     {
 519      // dumping last frame with frame::describe
 520 
 521       JavaThread* p = JavaThread::active();
 522 
 523       ResourceMark rm;
 524       PRESERVE_EXCEPTION_MARK; // may not be needed by safer and unexpensive here
 525       FrameValues values;
 526 
 527       // Note: We want to allow trace_method_handle from any call site.
 528       // While trace_method_handle creates a frame, it may be entered
 529       // without a PC on the stack top (e.g. not just after a call).
 530       // Walking that frame could lead to failures due to that invalid PC.
 531       // => carefully detect that frame when doing the stack walking
 532 
 533       // Current C frame
 534       frame cur_frame = os::current_frame();
 535 
 536       // Robust search of trace_calling_frame (independant of inlining).
 537       // Assumes saved_regs comes from a pusha in the trace_calling_frame.
 538       assert(cur_frame.sp() < saved_regs, "registers not saved on stack ?");
 539       frame trace_calling_frame = os::get_sender_for_C_frame(&cur_frame);
 540       while (trace_calling_frame.fp() < saved_regs) {
 541         trace_calling_frame = os::get_sender_for_C_frame(&trace_calling_frame);
 542       }
 543 
 544       // safely create a frame and call frame::describe
 545       intptr_t *dump_sp = trace_calling_frame.sender_sp();
 546       intptr_t *dump_fp = trace_calling_frame.link();
 547 
 548       bool walkable = has_mh; // whether the traced frame shoud be walkable
 549 
 550       if (walkable) {
 551         // The previous definition of walkable may have to be refined
 552         // if new call sites cause the next frame constructor to start
 553         // failing. Alternatively, frame constructors could be
 554         // modified to support the current or future non walkable
 555         // frames (but this is more intrusive and is not considered as
 556         // part of this RFE, which will instead use a simpler output).
 557         frame dump_frame = frame(dump_sp, dump_fp);
 558         dump_frame.describe(values, 1);
 559       } else {
 560         // Stack may not be walkable (invalid PC above FP):
 561         // Add descriptions without building a Java frame to avoid issues
 562         values.describe(-1, dump_fp, "fp for #1 <not parsed, cannot trust pc>");
 563         values.describe(-1, dump_sp, "sp for #1");
 564       }
 565       values.describe(-1, entry_sp, "raw top of stack");
 566 
 567       tty->print_cr("Stack layout:");
 568       values.print(p);
 569     }
 570     if (has_mh && oopDesc::is_oop(mh)) {
 571       mh->print();
 572       if (java_lang_invoke_MethodHandle::is_instance(mh)) {
 573         if (java_lang_invoke_MethodHandle::form_offset_in_bytes() != 0)
 574           java_lang_invoke_MethodHandle::form(mh)->print();
 575       }
 576     }
 577   }
 578 }
 579 
 580 // The stub wraps the arguments in a struct on the stack to avoid
 581 // dealing with the different calling conventions for passing 6
 582 // arguments.
 583 struct MethodHandleStubArguments {
 584   const char* adaptername;
 585   oopDesc* mh;
 586   intptr_t* saved_regs;
 587   intptr_t* entry_sp;
 588 };
 589 void trace_method_handle_stub_wrapper(MethodHandleStubArguments* args) {
 590   trace_method_handle_stub(args->adaptername,
 591                            args->mh,
 592                            args->saved_regs,
 593                            args->entry_sp);
 594 }
 595 
 596 void MethodHandles::trace_method_handle(MacroAssembler* _masm, const char* adaptername) {
 597   if (!TraceMethodHandles)  return;
 598   BLOCK_COMMENT(err_msg("trace_method_handle %s {", adaptername));
 599   __ enter();
 600   __ andptr(rsp, -16); // align stack if needed for FPU state
 601   __ pusha();
 602   __ mov(rbx, rsp); // for retreiving saved_regs
 603   // Note: saved_regs must be in the entered frame for the
 604   // robust stack walking implemented in trace_method_handle_stub.
 605 
 606   // save FP result, valid at some call sites (adapter_opt_return_float, ...)
 607   __ increment(rsp, -2 * wordSize);
 608   if  (UseSSE >= 2) {
 609     __ movdbl(Address(rsp, 0), xmm0);
 610   } else if (UseSSE == 1) {
 611     __ movflt(Address(rsp, 0), xmm0);
 612   } else {
 613     __ fst_d(Address(rsp, 0));
 614   }
 615 
 616   // Incoming state:
 617   // rcx: method handle
 618   //
 619   // To avoid calling convention issues, build a record on the stack
 620   // and pass the pointer to that instead.
 621   __ push(rbp);               // entry_sp (with extra align space)
 622   __ push(rbx);               // pusha saved_regs
 623   __ push(rcx);               // mh
 624   __ push(rcx);               // slot for adaptername
 625   __ movptr(Address(rsp, 0), (intptr_t) adaptername);
 626   __ super_call_VM_leaf(CAST_FROM_FN_PTR(address, trace_method_handle_stub_wrapper), rsp);
 627   __ increment(rsp, sizeof(MethodHandleStubArguments));
 628 
 629   if  (UseSSE >= 2) {
 630     __ movdbl(xmm0, Address(rsp, 0));
 631   } else if (UseSSE == 1) {
 632     __ movflt(xmm0, Address(rsp, 0));
 633   } else {
 634     __ fld_d(Address(rsp, 0));
 635   }
 636   __ increment(rsp, 2 * wordSize);
 637 
 638   __ popa();
 639   __ leave();
 640   BLOCK_COMMENT("} trace_method_handle");
 641 }
 642 #endif //PRODUCT