1 /*
  2  * Copyright (c) 1997, 2021, 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 "classfile/vmClasses.hpp"
 29 #include "compiler/disassembler.hpp"
 30 #include "classfile/javaClasses.inline.hpp"
 31 #include "interpreter/interpreter.hpp"
 32 #include "interpreter/interpreterRuntime.hpp"
 33 #include "logging/log.hpp"
 34 #include "logging/logStream.hpp"
 35 #include "memory/allocation.inline.hpp"
 36 #include "memory/resourceArea.hpp"
 37 #include "prims/jvmtiExport.hpp"
 38 #include "prims/methodHandles.hpp"
 39 #include "runtime/flags/flagSetting.hpp"
 40 #include "runtime/frame.inline.hpp"
 41 #include "runtime/stubRoutines.hpp"
 42 #include "utilities/formatBuffer.hpp"
 43 #include "utilities/preserveException.hpp"
 44 
 45 #define __ Disassembler::hook<MacroAssembler>(__FILE__, __LINE__, _masm)->
 46 
 47 #ifdef PRODUCT
 48 #define BLOCK_COMMENT(str) /* nothing */
 49 #define STOP(error) stop(error)
 50 #else
 51 #define BLOCK_COMMENT(str) __ block_comment(str)
 52 #define STOP(error) block_comment(error); __ stop(error)
 53 #endif
 54 
 55 #define BIND(label) bind(label); BLOCK_COMMENT(#label ":")
 56 
 57 void MethodHandles::load_klass_from_Class(MacroAssembler* _masm, Register klass_reg) {
 58   if (VerifyMethodHandles)
 59     verify_klass(_masm, klass_reg, VM_CLASS_ID(java_lang_Class),
 60                  "MH argument is a Class");
 61   __ movptr(klass_reg, Address(klass_reg, java_lang_Class::klass_offset()));
 62 }
 63 
 64 #ifdef ASSERT
 65 static int check_nonzero(const char* xname, int x) {
 66   assert(x != 0, "%s should be nonzero", xname);
 67   return x;
 68 }
 69 #define NONZERO(x) check_nonzero(#x, x)
 70 #else //ASSERT
 71 #define NONZERO(x) (x)
 72 #endif //ASSERT
 73 
 74 #ifdef ASSERT
 75 void MethodHandles::verify_klass(MacroAssembler* _masm,
 76                                  Register obj, vmClassID klass_id,
 77                                  const char* error_message) {
 78   InstanceKlass** klass_addr = vmClasses::klass_addr_at(klass_id);
 79   Klass* klass = vmClasses::klass_at(klass_id);
 80   Register temp = rdi;
 81   Register temp2 = noreg;
 82   LP64_ONLY(temp2 = rscratch1);  // used by MacroAssembler::cmpptr and load_klass
 83   Label L_ok, L_bad;
 84   BLOCK_COMMENT("verify_klass {");
 85   __ verify_oop(obj);
 86   __ testptr(obj, obj);
 87   __ jcc(Assembler::zero, L_bad);
 88   __ push(temp); if (temp2 != noreg)  __ push(temp2);
 89 #define UNPUSH { if (temp2 != noreg)  __ pop(temp2);  __ pop(temp); }
 90   __ load_klass(temp, obj, temp2);
 91   __ cmpptr(temp, ExternalAddress((address) klass_addr));
 92   __ jcc(Assembler::equal, L_ok);
 93   intptr_t super_check_offset = klass->super_check_offset();
 94   __ movptr(temp, Address(temp, super_check_offset));
 95   __ cmpptr(temp, ExternalAddress((address) klass_addr));
 96   __ jcc(Assembler::equal, L_ok);
 97   UNPUSH;
 98   __ bind(L_bad);
 99   __ STOP(error_message);
100   __ BIND(L_ok);
101   UNPUSH;
102   BLOCK_COMMENT("} verify_klass");
103 }
104 
105 void MethodHandles::verify_ref_kind(MacroAssembler* _masm, int ref_kind, Register member_reg, Register temp) {
106   Label L;
107   BLOCK_COMMENT("verify_ref_kind {");
108   __ movl(temp, Address(member_reg, NONZERO(java_lang_invoke_MemberName::flags_offset())));
109   __ shrl(temp, java_lang_invoke_MemberName::MN_REFERENCE_KIND_SHIFT);
110   __ andl(temp, java_lang_invoke_MemberName::MN_REFERENCE_KIND_MASK);
111   __ cmpl(temp, ref_kind);
112   __ jcc(Assembler::equal, L);
113   { char* buf = NEW_C_HEAP_ARRAY(char, 100, mtInternal);
114     jio_snprintf(buf, 100, "verify_ref_kind expected %x", ref_kind);
115     if (ref_kind == JVM_REF_invokeVirtual ||
116         ref_kind == JVM_REF_invokeSpecial)
117       // could do this for all ref_kinds, but would explode assembly code size
118       trace_method_handle(_masm, buf);
119     __ STOP(buf);
120   }
121   BLOCK_COMMENT("} verify_ref_kind");
122   __ bind(L);
123 }
124 
125 #endif //ASSERT
126 
127 void MethodHandles::jump_from_method_handle(MacroAssembler* _masm, Register method, Register temp,
128                                             bool for_compiler_entry) {
129   assert(method == rbx, "interpreter calling convention");
130 
131    Label L_no_such_method;
132    __ testptr(rbx, rbx);
133    __ jcc(Assembler::zero, L_no_such_method);
134 
135   __ verify_method_ptr(method);
136 
137   if (!for_compiler_entry && JvmtiExport::can_post_interpreter_events()) {
138     Label run_compiled_code;
139     // JVMTI events, such as single-stepping, are implemented partly by avoiding running
140     // compiled code in threads for which the event is enabled.  Check here for
141     // interp_only_mode if these events CAN be enabled.
142 #ifdef _LP64
143     Register rthread = r15_thread;
144 #else
145     Register rthread = temp;
146     __ get_thread(rthread);
147 #endif
148     // interp_only is an int, on little endian it is sufficient to test the byte only
149     // Is a cmpl faster?
150     __ cmpb(Address(rthread, JavaThread::interp_only_mode_offset()), 0);
151     __ jccb(Assembler::zero, run_compiled_code);
152     __ jmp(Address(method, Method::interpreter_entry_offset()));
153     __ BIND(run_compiled_code);
154   }
155 
156   const ByteSize entry_offset = for_compiler_entry ? Method::from_compiled_offset() :
157                                                      Method::from_interpreted_offset();
158   __ jmp(Address(method, entry_offset));
159 
160   __ bind(L_no_such_method);
161   __ jump(RuntimeAddress(StubRoutines::throw_AbstractMethodError_entry()));
162 }
163 
164 void MethodHandles::jump_to_lambda_form(MacroAssembler* _masm,
165                                         Register recv, Register method_temp,
166                                         Register temp2,
167                                         bool for_compiler_entry) {
168   BLOCK_COMMENT("jump_to_lambda_form {");
169   // This is the initial entry point of a lazy method handle.
170   // After type checking, it picks up the invoker from the LambdaForm.
171   assert_different_registers(recv, method_temp, temp2);
172   assert(recv != noreg, "required register");
173   assert(method_temp == rbx, "required register for loading method");
174 
175   // Load the invoker, as MH -> MH.form -> LF.vmentry
176   __ verify_oop(recv);
177   __ load_heap_oop(method_temp, Address(recv, NONZERO(java_lang_invoke_MethodHandle::form_offset())), temp2);
178   __ verify_oop(method_temp);
179   __ load_heap_oop(method_temp, Address(method_temp, NONZERO(java_lang_invoke_LambdaForm::vmentry_offset())), temp2);
180   __ verify_oop(method_temp);
181   __ load_heap_oop(method_temp, Address(method_temp, NONZERO(java_lang_invoke_MemberName::method_offset())), temp2);
182   __ verify_oop(method_temp);
183   __ access_load_at(T_ADDRESS, IN_HEAP, method_temp,
184                     Address(method_temp, NONZERO(java_lang_invoke_ResolvedMethodName::vmtarget_offset())),
185                     noreg, noreg);
186 
187   if (VerifyMethodHandles && !for_compiler_entry) {
188     // make sure recv is already on stack
189     __ movptr(temp2, Address(method_temp, Method::const_offset()));
190     __ load_sized_value(temp2,
191                         Address(temp2, ConstMethod::size_of_parameters_offset()),
192                         sizeof(u2), /*is_signed*/ false);
193     // assert(sizeof(u2) == sizeof(Method::_size_of_parameters), "");
194     Label L;
195     __ cmpoop(recv, __ argument_address(temp2, -1));
196     __ jcc(Assembler::equal, L);
197     __ movptr(rax, __ argument_address(temp2, -1));
198     __ STOP("receiver not on stack");
199     __ BIND(L);
200   }
201 
202   jump_from_method_handle(_masm, method_temp, temp2, for_compiler_entry);
203   BLOCK_COMMENT("} jump_to_lambda_form");
204 }
205 
206 void MethodHandles::jump_to_native_invoker(MacroAssembler* _masm, Register nep_reg, Register temp_target) {
207   BLOCK_COMMENT("jump_to_native_invoker {");
208   assert_different_registers(nep_reg, temp_target);
209   assert(nep_reg != noreg, "required register");
210 
211   // Load the invoker, as NEP -> .invoker
212   __ verify_oop(nep_reg);
213   __ access_load_at(T_ADDRESS, IN_HEAP, temp_target,
214                     Address(nep_reg, NONZERO(jdk_internal_invoke_NativeEntryPoint::invoker_offset_in_bytes())),
215                     noreg, noreg);
216 
217   __ jmp(temp_target);
218   BLOCK_COMMENT("} jump_to_native_invoker");
219 }
220 
221 
222 // Code generation
223 address MethodHandles::generate_method_handle_interpreter_entry(MacroAssembler* _masm,
224                                                                 vmIntrinsics::ID iid) {
225   const bool not_for_compiler_entry = false;  // this is the interpreter entry
226   assert(is_signature_polymorphic(iid), "expected invoke iid");
227   if (iid == vmIntrinsics::_invokeGeneric ||
228       iid == vmIntrinsics::_compiledLambdaForm) {
229     // Perhaps surprisingly, the symbolic references visible to Java are not directly used.
230     // They are linked to Java-generated adapters via MethodHandleNatives.linkMethod.
231     // They all allow an appendix argument.
232     __ hlt();           // empty stubs make SG sick
233     return NULL;
234   }
235 
236   // No need in interpreter entry for linkToNative for now.
237   // Interpreter calls compiled entry through i2c.
238   if (iid == vmIntrinsics::_linkToNative) {
239     __ hlt();
240     return NULL;
241   }
242 
243   // rsi/r13: sender SP (must preserve; see prepare_to_jump_from_interpreted)
244   // rbx: Method*
245   // rdx: argument locator (parameter slot count, added to rsp)
246   // rcx: used as temp to hold mh or receiver
247   // rax, rdi: garbage temps, blown away
248   Register rdx_argp   = rdx;   // argument list ptr, live on error paths
249   Register rax_temp   = rax;
250   Register rcx_mh     = rcx;   // MH receiver; dies quickly and is recycled
251   Register rbx_method = rbx;   // eventual target of this invocation
252 
253   // here's where control starts out:
254   __ align(CodeEntryAlignment);
255   address entry_point = __ pc();
256 
257   if (VerifyMethodHandles) {
258     assert(Method::intrinsic_id_size_in_bytes() == 2, "assuming Method::_intrinsic_id is u2");
259 
260     Label L;
261     BLOCK_COMMENT("verify_intrinsic_id {");
262     __ cmpw(Address(rbx_method, Method::intrinsic_id_offset_in_bytes()), (int) iid);
263     __ jcc(Assembler::equal, L);
264     if (iid == vmIntrinsics::_linkToVirtual ||
265         iid == vmIntrinsics::_linkToSpecial) {
266       // could do this for all kinds, but would explode assembly code size
267       trace_method_handle(_masm, "bad Method*::intrinsic_id");
268     }
269     __ STOP("bad Method*::intrinsic_id");
270     __ bind(L);
271     BLOCK_COMMENT("} verify_intrinsic_id");
272   }
273 
274   // First task:  Find out how big the argument list is.
275   Address rdx_first_arg_addr;
276   int ref_kind = signature_polymorphic_intrinsic_ref_kind(iid);
277   assert(ref_kind != 0 || iid == vmIntrinsics::_invokeBasic, "must be _invokeBasic or a linkTo intrinsic");
278   if (ref_kind == 0 || MethodHandles::ref_kind_has_receiver(ref_kind)) {
279     __ movptr(rdx_argp, Address(rbx_method, Method::const_offset()));
280     __ load_sized_value(rdx_argp,
281                         Address(rdx_argp, ConstMethod::size_of_parameters_offset()),
282                         sizeof(u2), /*is_signed*/ false);
283     // assert(sizeof(u2) == sizeof(Method::_size_of_parameters), "");
284     rdx_first_arg_addr = __ argument_address(rdx_argp, -1);
285   } else {
286     DEBUG_ONLY(rdx_argp = noreg);
287   }
288 
289   if (!is_signature_polymorphic_static(iid)) {
290     __ movptr(rcx_mh, rdx_first_arg_addr);
291     DEBUG_ONLY(rdx_argp = noreg);
292   }
293 
294   // rdx_first_arg_addr is live!
295 
296   trace_method_handle_interpreter_entry(_masm, iid);
297 
298   if (iid == vmIntrinsics::_invokeBasic) {
299     generate_method_handle_dispatch(_masm, iid, rcx_mh, noreg, not_for_compiler_entry);
300 
301   } else {
302     // Adjust argument list by popping the trailing MemberName argument.
303     Register rcx_recv = noreg;
304     if (MethodHandles::ref_kind_has_receiver(ref_kind)) {
305       // Load the receiver (not the MH; the actual MemberName's receiver) up from the interpreter stack.
306       __ movptr(rcx_recv = rcx, rdx_first_arg_addr);
307     }
308     DEBUG_ONLY(rdx_argp = noreg);
309     Register rbx_member = rbx_method;  // MemberName ptr; incoming method ptr is dead now
310     __ pop(rax_temp);           // return address
311     __ pop(rbx_member);         // extract last argument
312     __ push(rax_temp);          // re-push return address
313     generate_method_handle_dispatch(_masm, iid, rcx_recv, rbx_member, not_for_compiler_entry);
314   }
315 
316   return entry_point;
317 }
318 
319 void MethodHandles::generate_method_handle_dispatch(MacroAssembler* _masm,
320                                                     vmIntrinsics::ID iid,
321                                                     Register receiver_reg,
322                                                     Register member_reg,
323                                                     bool for_compiler_entry) {
324   assert(is_signature_polymorphic(iid), "expected invoke iid");
325   Register rbx_method = rbx;   // eventual target of this invocation
326   // temps used in this code are not used in *either* compiled or interpreted calling sequences
327 #ifdef _LP64
328   Register temp1 = rscratch1;
329   Register temp2 = rscratch2;
330   Register temp3 = rax;
331   if (for_compiler_entry) {
332     assert(receiver_reg == (iid == vmIntrinsics::_linkToStatic || iid == vmIntrinsics::_linkToNative ? noreg : j_rarg0), "only valid assignment");
333     assert_different_registers(temp1,        j_rarg0, j_rarg1, j_rarg2, j_rarg3, j_rarg4, j_rarg5);
334     assert_different_registers(temp2,        j_rarg0, j_rarg1, j_rarg2, j_rarg3, j_rarg4, j_rarg5);
335     assert_different_registers(temp3,        j_rarg0, j_rarg1, j_rarg2, j_rarg3, j_rarg4, j_rarg5);
336   }
337 #else
338   Register temp1 = (for_compiler_entry ? rsi : rdx);
339   Register temp2 = rdi;
340   Register temp3 = rax;
341   if (for_compiler_entry) {
342     assert(receiver_reg == (iid == vmIntrinsics::_linkToStatic || iid == vmIntrinsics::_linkToNative ? noreg : rcx), "only valid assignment");
343     assert_different_registers(temp1,        rcx, rdx);
344     assert_different_registers(temp2,        rcx, rdx);
345     assert_different_registers(temp3,        rcx, rdx);
346   }
347 #endif
348   else {
349     assert_different_registers(temp1, temp2, temp3, saved_last_sp_register());  // don't trash lastSP
350   }
351   assert_different_registers(temp1, temp2, temp3, receiver_reg);
352   assert_different_registers(temp1, temp2, temp3, member_reg);
353 
354   if (iid == vmIntrinsics::_invokeBasic) {
355     // indirect through MH.form.vmentry.vmtarget
356     jump_to_lambda_form(_masm, receiver_reg, rbx_method, temp1, for_compiler_entry);
357   } else if (iid == vmIntrinsics::_linkToNative) {
358     assert(for_compiler_entry, "only compiler entry is supported");
359     jump_to_native_invoker(_masm, member_reg, temp1);
360   } else {
361     // The method is a member invoker used by direct method handles.
362     if (VerifyMethodHandles) {
363       // make sure the trailing argument really is a MemberName (caller responsibility)
364       verify_klass(_masm, member_reg, VM_CLASS_ID(java_lang_invoke_MemberName),
365                    "MemberName required for invokeVirtual etc.");
366     }
367 
368     Address member_clazz(    member_reg, NONZERO(java_lang_invoke_MemberName::clazz_offset()));
369     Address member_vmindex(  member_reg, NONZERO(java_lang_invoke_MemberName::vmindex_offset()));
370     Address member_vmtarget( member_reg, NONZERO(java_lang_invoke_MemberName::method_offset()));
371     Address vmtarget_method( rbx_method, NONZERO(java_lang_invoke_ResolvedMethodName::vmtarget_offset()));
372 
373     Register temp1_recv_klass = temp1;
374     if (iid != vmIntrinsics::_linkToStatic) {
375       __ verify_oop(receiver_reg);
376       if (iid == vmIntrinsics::_linkToSpecial) {
377         // Don't actually load the klass; just null-check the receiver.
378         __ null_check(receiver_reg);
379       } else {
380         // load receiver klass itself
381         __ null_check(receiver_reg, oopDesc::klass_offset_in_bytes());
382         __ load_klass(temp1_recv_klass, receiver_reg, temp2);
383         __ verify_klass_ptr(temp1_recv_klass);
384       }
385       BLOCK_COMMENT("check_receiver {");
386       // The receiver for the MemberName must be in receiver_reg.
387       // Check the receiver against the MemberName.clazz
388       if (VerifyMethodHandles && iid == vmIntrinsics::_linkToSpecial) {
389         // Did not load it above...
390         __ load_klass(temp1_recv_klass, receiver_reg, temp2);
391         __ verify_klass_ptr(temp1_recv_klass);
392       }
393       if (VerifyMethodHandles && iid != vmIntrinsics::_linkToInterface) {
394         Label L_ok;
395         Register temp2_defc = temp2;
396         __ load_heap_oop(temp2_defc, member_clazz, temp3);
397         load_klass_from_Class(_masm, temp2_defc);
398         __ verify_klass_ptr(temp2_defc);
399         __ check_klass_subtype(temp1_recv_klass, temp2_defc, temp3, L_ok);
400         // If we get here, the type check failed!
401         __ STOP("receiver class disagrees with MemberName.clazz");
402         __ bind(L_ok);
403       }
404       BLOCK_COMMENT("} check_receiver");
405     }
406     if (iid == vmIntrinsics::_linkToSpecial ||
407         iid == vmIntrinsics::_linkToStatic) {
408       DEBUG_ONLY(temp1_recv_klass = noreg);  // these guys didn't load the recv_klass
409     }
410 
411     // Live registers at this point:
412     //  member_reg - MemberName that was the trailing argument
413     //  temp1_recv_klass - klass of stacked receiver, if needed
414     //  rsi/r13 - interpreter linkage (if interpreted)
415     //  rcx, rdx, rsi, rdi, r8 - compiler arguments (if compiled)
416 
417     Label L_incompatible_class_change_error;
418     switch (iid) {
419     case vmIntrinsics::_linkToSpecial:
420       if (VerifyMethodHandles) {
421         verify_ref_kind(_masm, JVM_REF_invokeSpecial, member_reg, temp3);
422       }
423       __ load_heap_oop(rbx_method, member_vmtarget);
424       __ access_load_at(T_ADDRESS, IN_HEAP, rbx_method, vmtarget_method, noreg, noreg);
425       break;
426 
427     case vmIntrinsics::_linkToStatic:
428       if (VerifyMethodHandles) {
429         verify_ref_kind(_masm, JVM_REF_invokeStatic, member_reg, temp3);
430       }
431       __ load_heap_oop(rbx_method, member_vmtarget);
432       __ access_load_at(T_ADDRESS, IN_HEAP, rbx_method, vmtarget_method, noreg, noreg);
433       break;
434 
435     case vmIntrinsics::_linkToVirtual:
436     {
437       // same as TemplateTable::invokevirtual,
438       // minus the CP setup and profiling:
439 
440       if (VerifyMethodHandles) {
441         verify_ref_kind(_masm, JVM_REF_invokeVirtual, member_reg, temp3);
442       }
443 
444       // pick out the vtable index from the MemberName, and then we can discard it:
445       Register temp2_index = temp2;
446       __ access_load_at(T_ADDRESS, IN_HEAP, temp2_index, member_vmindex, noreg, noreg);
447 
448       if (VerifyMethodHandles) {
449         Label L_index_ok;
450         __ cmpl(temp2_index, 0);
451         __ jcc(Assembler::greaterEqual, L_index_ok);
452         __ STOP("no virtual index");
453         __ BIND(L_index_ok);
454       }
455 
456       // Note:  The verifier invariants allow us to ignore MemberName.clazz and vmtarget
457       // at this point.  And VerifyMethodHandles has already checked clazz, if needed.
458 
459       // get target Method* & entry point
460       __ lookup_virtual_method(temp1_recv_klass, temp2_index, rbx_method);
461       break;
462     }
463 
464     case vmIntrinsics::_linkToInterface:
465     {
466       // same as TemplateTable::invokeinterface
467       // (minus the CP setup and profiling, with different argument motion)
468       if (VerifyMethodHandles) {
469         verify_ref_kind(_masm, JVM_REF_invokeInterface, member_reg, temp3);
470       }
471 
472       Register temp3_intf = temp3;
473       __ load_heap_oop(temp3_intf, member_clazz);
474       load_klass_from_Class(_masm, temp3_intf);
475       __ verify_klass_ptr(temp3_intf);
476 
477       Register rbx_index = rbx_method;
478       __ access_load_at(T_ADDRESS, IN_HEAP, rbx_index, member_vmindex, noreg, noreg);
479       if (VerifyMethodHandles) {
480         Label L;
481         __ cmpl(rbx_index, 0);
482         __ jcc(Assembler::greaterEqual, L);
483         __ STOP("invalid vtable index for MH.invokeInterface");
484         __ bind(L);
485       }
486 
487       // given intf, index, and recv klass, dispatch to the implementation method
488       __ lookup_interface_method(temp1_recv_klass, temp3_intf,
489                                  // note: next two args must be the same:
490                                  rbx_index, rbx_method,
491                                  temp2,
492                                  L_incompatible_class_change_error);
493       break;
494     }
495 
496     default:
497       fatal("unexpected intrinsic %d: %s", vmIntrinsics::as_int(iid), vmIntrinsics::name_at(iid));
498       break;
499     }
500 
501     // Live at this point:
502     //   rbx_method
503     //   rsi/r13 (if interpreted)
504 
505     // After figuring out which concrete method to call, jump into it.
506     // Note that this works in the interpreter with no data motion.
507     // But the compiled version will require that rcx_recv be shifted out.
508     __ verify_method_ptr(rbx_method);
509     jump_from_method_handle(_masm, rbx_method, temp1, for_compiler_entry);
510 
511     if (iid == vmIntrinsics::_linkToInterface) {
512       __ bind(L_incompatible_class_change_error);
513       __ jump(RuntimeAddress(StubRoutines::throw_IncompatibleClassChangeError_entry()));
514     }
515   }
516 }
517 
518 #ifndef PRODUCT
519 void trace_method_handle_stub(const char* adaptername,
520                               oopDesc* mh,
521                               intptr_t* saved_regs,
522                               intptr_t* entry_sp) {
523   // called as a leaf from native code: do not block the JVM!
524   bool has_mh = (strstr(adaptername, "/static") == NULL &&
525                  strstr(adaptername, "linkTo") == NULL);    // static linkers don't have MH
526   const char* mh_reg_name = has_mh ? "rcx_mh" : "rcx";
527   log_info(methodhandles)("MH %s %s=" PTR_FORMAT " sp=" PTR_FORMAT, adaptername, mh_reg_name, p2i(mh), p2i(entry_sp));
528 
529   LogTarget(Trace, methodhandles) lt;
530   if (lt.is_enabled()) {
531     ResourceMark rm;
532     LogStream ls(lt);
533     ls.print_cr("Registers:");
534     const int saved_regs_count = RegisterImpl::number_of_registers;
535     for (int i = 0; i < saved_regs_count; i++) {
536       Register r = as_Register(i);
537       // The registers are stored in reverse order on the stack (by pusha).
538 #ifdef AMD64
539       assert(RegisterImpl::number_of_registers == 16, "sanity");
540       if (r == rsp) {
541         // rsp is actually not stored by pusha(), compute the old rsp from saved_regs (rsp after pusha): saved_regs + 16 = old rsp
542         ls.print("%3s=" PTR_FORMAT, r->name(), (intptr_t)(&saved_regs[16]));
543       } else {
544         ls.print("%3s=" PTR_FORMAT, r->name(), saved_regs[((saved_regs_count - 1) - i)]);
545       }
546 #else
547       ls.print("%3s=" PTR_FORMAT, r->name(), saved_regs[((saved_regs_count - 1) - i)]);
548 #endif
549       if ((i + 1) % 4 == 0) {
550         ls.cr();
551       } else {
552         ls.print(", ");
553       }
554     }
555     ls.cr();
556 
557     // Note: We want to allow trace_method_handle from any call site.
558     // While trace_method_handle creates a frame, it may be entered
559     // without a PC on the stack top (e.g. not just after a call).
560     // Walking that frame could lead to failures due to that invalid PC.
561     // => carefully detect that frame when doing the stack walking
562 
563     {
564       // dumping last frame with frame::describe
565 
566       JavaThread* p = JavaThread::active();
567 
568       // may not be needed by safer and unexpensive here
569       PreserveExceptionMark pem(Thread::current());
570       FrameValues values;
571 
572       frame cur_frame = os::current_frame();
573 
574       if (cur_frame.fp() != 0) {  // not walkable
575 
576         // Robust search of trace_calling_frame (independent of inlining).
577         // Assumes saved_regs comes from a pusha in the trace_calling_frame.
578         //
579         // We have to start the search from cur_frame, because trace_calling_frame may be it.
580         // It is guaranteed that trace_calling_frame is different from the top frame.
581         // But os::current_frame() does NOT return the top frame: it returns the next frame under it (caller's frame).
582         // (Due to inlining and tail call optimizations, caller's frame doesn't necessarily correspond to the immediate
583         // caller in the source code.)
584         assert(cur_frame.sp() < saved_regs, "registers not saved on stack ?");
585         frame trace_calling_frame = cur_frame;
586         while (trace_calling_frame.fp() < saved_regs) {
587           assert(trace_calling_frame.cb() == NULL, "not a C frame");
588           trace_calling_frame = os::get_sender_for_C_frame(&trace_calling_frame);
589         }
590         assert(trace_calling_frame.sp() < saved_regs, "wrong frame");
591 
592         // safely create a frame and call frame::describe
593         intptr_t *dump_sp = trace_calling_frame.sender_sp();
594         intptr_t *dump_fp = trace_calling_frame.link();
595 
596         if (has_mh) {
597           // The previous definition of walkable may have to be refined
598           // if new call sites cause the next frame constructor to start
599           // failing. Alternatively, frame constructors could be
600           // modified to support the current or future non walkable
601           // frames (but this is more intrusive and is not considered as
602           // part of this RFE, which will instead use a simpler output).
603           frame dump_frame = frame(dump_sp, dump_fp);
604           dump_frame.describe(values, 1);
605         } else {
606           // Stack may not be walkable (invalid PC above FP):
607           // Add descriptions without building a Java frame to avoid issues
608           values.describe(-1, dump_fp, "fp for #1 <not parsed, cannot trust pc>");
609           values.describe(-1, dump_sp, "sp for #1");
610         }
611       }
612       values.describe(-1, entry_sp, "raw top of stack");
613 
614       ls.print_cr("Stack layout:");
615       values.print_on(p, &ls);
616     }
617     if (has_mh && oopDesc::is_oop(mh)) {
618       mh->print_on(&ls);
619       if (java_lang_invoke_MethodHandle::is_instance(mh)) {
620         java_lang_invoke_MethodHandle::form(mh)->print_on(&ls);
621       }
622     }
623   }
624 }
625 
626 // The stub wraps the arguments in a struct on the stack to avoid
627 // dealing with the different calling conventions for passing 6
628 // arguments.
629 struct MethodHandleStubArguments {
630   const char* adaptername;
631   oopDesc* mh;
632   intptr_t* saved_regs;
633   intptr_t* entry_sp;
634 };
635 void trace_method_handle_stub_wrapper(MethodHandleStubArguments* args) {
636   trace_method_handle_stub(args->adaptername,
637                            args->mh,
638                            args->saved_regs,
639                            args->entry_sp);
640 }
641 
642 void MethodHandles::trace_method_handle(MacroAssembler* _masm, const char* adaptername) {
643   if (!log_is_enabled(Info, methodhandles))  return;
644   BLOCK_COMMENT(err_msg("trace_method_handle %s {", adaptername));
645   __ enter();
646   __ andptr(rsp, -16); // align stack if needed for FPU state
647   __ pusha();
648   __ mov(rbx, rsp); // for retreiving saved_regs
649   // Note: saved_regs must be in the entered frame for the
650   // robust stack walking implemented in trace_method_handle_stub.
651 
652   // save FP result, valid at some call sites (adapter_opt_return_float, ...)
653   __ decrement(rsp, 2 * wordSize);
654 #ifdef _LP64
655   __ movdbl(Address(rsp, 0), xmm0);
656 #else
657   if  (UseSSE >= 2) {
658     __ movdbl(Address(rsp, 0), xmm0);
659   } else if (UseSSE == 1) {
660     __ movflt(Address(rsp, 0), xmm0);
661   } else {
662     __ fst_d(Address(rsp, 0));
663   }
664 #endif // LP64
665 
666   // Incoming state:
667   // rcx: method handle
668   //
669   // To avoid calling convention issues, build a record on the stack
670   // and pass the pointer to that instead.
671   __ push(rbp);               // entry_sp (with extra align space)
672   __ push(rbx);               // pusha saved_regs
673   __ push(rcx);               // mh
674   __ push(rcx);               // slot for adaptername
675   __ movptr(Address(rsp, 0), (intptr_t) adaptername);
676   __ super_call_VM_leaf(CAST_FROM_FN_PTR(address, trace_method_handle_stub_wrapper), rsp);
677   __ increment(rsp, sizeof(MethodHandleStubArguments));
678 
679 #ifdef _LP64
680   __ movdbl(xmm0, Address(rsp, 0));
681 #else
682   if  (UseSSE >= 2) {
683     __ movdbl(xmm0, Address(rsp, 0));
684   } else if (UseSSE == 1) {
685     __ movflt(xmm0, Address(rsp, 0));
686   } else {
687     __ fld_d(Address(rsp, 0));
688   }
689 #endif // LP64
690   __ increment(rsp, 2 * wordSize);
691 
692   __ popa();
693   __ leave();
694   BLOCK_COMMENT("} trace_method_handle");
695 }
696 #endif //PRODUCT