1 /*
  2  * Copyright (c) 1997, 2022, 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 
207 // Code generation
208 address MethodHandles::generate_method_handle_interpreter_entry(MacroAssembler* _masm,
209                                                                 vmIntrinsics::ID iid) {
210   const bool not_for_compiler_entry = false;  // this is the interpreter entry
211   assert(is_signature_polymorphic(iid), "expected invoke iid");
212   if (iid == vmIntrinsics::_invokeGeneric ||
213       iid == vmIntrinsics::_compiledLambdaForm) {
214     // Perhaps surprisingly, the symbolic references visible to Java are not directly used.
215     // They are linked to Java-generated adapters via MethodHandleNatives.linkMethod.
216     // They all allow an appendix argument.
217     __ hlt();           // empty stubs make SG sick
218     return NULL;
219   }
220 
221   // No need in interpreter entry for linkToNative for now.
222   // Interpreter calls compiled entry through i2c.
223   if (iid == vmIntrinsics::_linkToNative) {
224     __ hlt();
225     return NULL;
226   }
227 
228   // rsi/r13: sender SP (must preserve; see prepare_to_jump_from_interpreted)
229   // rbx: Method*
230   // rdx: argument locator (parameter slot count, added to rsp)
231   // rcx: used as temp to hold mh or receiver
232   // rax, rdi: garbage temps, blown away
233   Register rdx_argp   = rdx;   // argument list ptr, live on error paths
234   Register rax_temp   = rax;
235   Register rcx_mh     = rcx;   // MH receiver; dies quickly and is recycled
236   Register rbx_method = rbx;   // eventual target of this invocation
237 
238   // here's where control starts out:
239   __ align(CodeEntryAlignment);
240   address entry_point = __ pc();
241 
242   if (VerifyMethodHandles) {
243     assert(Method::intrinsic_id_size_in_bytes() == 2, "assuming Method::_intrinsic_id is u2");
244 
245     Label L;
246     BLOCK_COMMENT("verify_intrinsic_id {");
247     __ cmpw(Address(rbx_method, Method::intrinsic_id_offset_in_bytes()), (int) iid);
248     __ jcc(Assembler::equal, L);
249     if (iid == vmIntrinsics::_linkToVirtual ||
250         iid == vmIntrinsics::_linkToSpecial) {
251       // could do this for all kinds, but would explode assembly code size
252       trace_method_handle(_masm, "bad Method*::intrinsic_id");
253     }
254     __ STOP("bad Method*::intrinsic_id");
255     __ bind(L);
256     BLOCK_COMMENT("} verify_intrinsic_id");
257   }
258 
259   // First task:  Find out how big the argument list is.
260   Address rdx_first_arg_addr;
261   int ref_kind = signature_polymorphic_intrinsic_ref_kind(iid);
262   assert(ref_kind != 0 || iid == vmIntrinsics::_invokeBasic, "must be _invokeBasic or a linkTo intrinsic");
263   if (ref_kind == 0 || MethodHandles::ref_kind_has_receiver(ref_kind)) {
264     __ movptr(rdx_argp, Address(rbx_method, Method::const_offset()));
265     __ load_sized_value(rdx_argp,
266                         Address(rdx_argp, ConstMethod::size_of_parameters_offset()),
267                         sizeof(u2), /*is_signed*/ false);
268     // assert(sizeof(u2) == sizeof(Method::_size_of_parameters), "");
269     rdx_first_arg_addr = __ argument_address(rdx_argp, -1);
270   } else {
271     DEBUG_ONLY(rdx_argp = noreg);
272   }
273 
274   if (!is_signature_polymorphic_static(iid)) {
275     __ movptr(rcx_mh, rdx_first_arg_addr);
276     DEBUG_ONLY(rdx_argp = noreg);
277   }
278 
279   // rdx_first_arg_addr is live!
280 
281   trace_method_handle_interpreter_entry(_masm, iid);
282 
283   if (iid == vmIntrinsics::_invokeBasic) {
284     generate_method_handle_dispatch(_masm, iid, rcx_mh, noreg, not_for_compiler_entry);
285 
286   } else {
287     // Adjust argument list by popping the trailing MemberName argument.
288     Register rcx_recv = noreg;
289     if (MethodHandles::ref_kind_has_receiver(ref_kind)) {
290       // Load the receiver (not the MH; the actual MemberName's receiver) up from the interpreter stack.
291       __ movptr(rcx_recv = rcx, rdx_first_arg_addr);
292     }
293     DEBUG_ONLY(rdx_argp = noreg);
294     Register rbx_member = rbx_method;  // MemberName ptr; incoming method ptr is dead now
295     __ pop(rax_temp);           // return address
296     __ pop(rbx_member);         // extract last argument
297     __ push(rax_temp);          // re-push return address
298     generate_method_handle_dispatch(_masm, iid, rcx_recv, rbx_member, not_for_compiler_entry);
299   }
300 
301   return entry_point;
302 }
303 
304 void MethodHandles::generate_method_handle_dispatch(MacroAssembler* _masm,
305                                                     vmIntrinsics::ID iid,
306                                                     Register receiver_reg,
307                                                     Register member_reg,
308                                                     bool for_compiler_entry) {
309   assert(is_signature_polymorphic(iid), "expected invoke iid");
310   Register rbx_method = rbx;   // eventual target of this invocation
311   // temps used in this code are not used in *either* compiled or interpreted calling sequences
312 #ifdef _LP64
313   Register temp1 = rscratch1;
314   Register temp2 = rscratch2;
315   Register temp3 = rax;
316   if (for_compiler_entry) {
317     assert(receiver_reg == (iid == vmIntrinsics::_linkToStatic ? noreg : j_rarg0), "only valid assignment");
318     assert_different_registers(temp1,        j_rarg0, j_rarg1, j_rarg2, j_rarg3, j_rarg4, j_rarg5);
319     assert_different_registers(temp2,        j_rarg0, j_rarg1, j_rarg2, j_rarg3, j_rarg4, j_rarg5);
320     assert_different_registers(temp3,        j_rarg0, j_rarg1, j_rarg2, j_rarg3, j_rarg4, j_rarg5);
321   }
322 #else
323   Register temp1 = (for_compiler_entry ? rsi : rdx);
324   Register temp2 = rdi;
325   Register temp3 = rax;
326   if (for_compiler_entry) {
327     assert(receiver_reg == (iid == vmIntrinsics::_linkToStatic ? noreg : rcx), "only valid assignment");
328     assert_different_registers(temp1,        rcx, rdx);
329     assert_different_registers(temp2,        rcx, rdx);
330     assert_different_registers(temp3,        rcx, rdx);
331   }
332 #endif
333   else {
334     assert_different_registers(temp1, temp2, temp3, saved_last_sp_register());  // don't trash lastSP
335   }
336   assert_different_registers(temp1, temp2, temp3, receiver_reg);
337   assert_different_registers(temp1, temp2, temp3, member_reg);
338 
339   if (iid == vmIntrinsics::_invokeBasic || iid == vmIntrinsics::_linkToNative) {
340     if (iid == vmIntrinsics::_linkToNative) {
341       assert(for_compiler_entry, "only compiler entry is supported");
342     }
343     // indirect through MH.form.vmentry.vmtarget
344     jump_to_lambda_form(_masm, receiver_reg, rbx_method, temp1, for_compiler_entry);
345 
346   } else {
347     // The method is a member invoker used by direct method handles.
348     if (VerifyMethodHandles) {
349       // make sure the trailing argument really is a MemberName (caller responsibility)
350       verify_klass(_masm, member_reg, VM_CLASS_ID(java_lang_invoke_MemberName),
351                    "MemberName required for invokeVirtual etc.");
352     }
353 
354     Address member_clazz(    member_reg, NONZERO(java_lang_invoke_MemberName::clazz_offset()));
355     Address member_vmindex(  member_reg, NONZERO(java_lang_invoke_MemberName::vmindex_offset()));
356     Address member_vmtarget( member_reg, NONZERO(java_lang_invoke_MemberName::method_offset()));
357     Address vmtarget_method( rbx_method, NONZERO(java_lang_invoke_ResolvedMethodName::vmtarget_offset()));
358 
359     Register temp1_recv_klass = temp1;
360     if (iid != vmIntrinsics::_linkToStatic) {
361       __ verify_oop(receiver_reg);
362       if (iid == vmIntrinsics::_linkToSpecial) {
363         // Don't actually load the klass; just null-check the receiver.
364         __ null_check(receiver_reg);
365       } else {
366         // load receiver klass itself
367         __ load_klass(temp1_recv_klass, receiver_reg, temp2, true);
368         __ verify_klass_ptr(temp1_recv_klass);
369       }
370       BLOCK_COMMENT("check_receiver {");
371       // The receiver for the MemberName must be in receiver_reg.
372       // Check the receiver against the MemberName.clazz
373       if (VerifyMethodHandles && iid == vmIntrinsics::_linkToSpecial) {
374         // Did not load it above...
375         __ load_klass(temp1_recv_klass, receiver_reg, temp2);
376         __ verify_klass_ptr(temp1_recv_klass);
377       }
378       if (VerifyMethodHandles && iid != vmIntrinsics::_linkToInterface) {
379         Label L_ok;
380         Register temp2_defc = temp2;
381         __ load_heap_oop(temp2_defc, member_clazz, temp3);
382         load_klass_from_Class(_masm, temp2_defc);
383         __ verify_klass_ptr(temp2_defc);
384         __ check_klass_subtype(temp1_recv_klass, temp2_defc, temp3, L_ok);
385         // If we get here, the type check failed!
386         __ STOP("receiver class disagrees with MemberName.clazz");
387         __ bind(L_ok);
388       }
389       BLOCK_COMMENT("} check_receiver");
390     }
391     if (iid == vmIntrinsics::_linkToSpecial ||
392         iid == vmIntrinsics::_linkToStatic) {
393       DEBUG_ONLY(temp1_recv_klass = noreg);  // these guys didn't load the recv_klass
394     }
395 
396     // Live registers at this point:
397     //  member_reg - MemberName that was the trailing argument
398     //  temp1_recv_klass - klass of stacked receiver, if needed
399     //  rsi/r13 - interpreter linkage (if interpreted)
400     //  rcx, rdx, rsi, rdi, r8 - compiler arguments (if compiled)
401 
402     Label L_incompatible_class_change_error;
403     switch (iid) {
404     case vmIntrinsics::_linkToSpecial:
405       if (VerifyMethodHandles) {
406         verify_ref_kind(_masm, JVM_REF_invokeSpecial, member_reg, temp3);
407       }
408       __ load_heap_oop(rbx_method, member_vmtarget);
409       __ access_load_at(T_ADDRESS, IN_HEAP, rbx_method, vmtarget_method, noreg, noreg);
410       break;
411 
412     case vmIntrinsics::_linkToStatic:
413       if (VerifyMethodHandles) {
414         verify_ref_kind(_masm, JVM_REF_invokeStatic, member_reg, temp3);
415       }
416       __ load_heap_oop(rbx_method, member_vmtarget);
417       __ access_load_at(T_ADDRESS, IN_HEAP, rbx_method, vmtarget_method, noreg, noreg);
418       break;
419 
420     case vmIntrinsics::_linkToVirtual:
421     {
422       // same as TemplateTable::invokevirtual,
423       // minus the CP setup and profiling:
424 
425       if (VerifyMethodHandles) {
426         verify_ref_kind(_masm, JVM_REF_invokeVirtual, member_reg, temp3);
427       }
428 
429       // pick out the vtable index from the MemberName, and then we can discard it:
430       Register temp2_index = temp2;
431       __ access_load_at(T_ADDRESS, IN_HEAP, temp2_index, member_vmindex, noreg, noreg);
432 
433       if (VerifyMethodHandles) {
434         Label L_index_ok;
435         __ cmpl(temp2_index, 0);
436         __ jcc(Assembler::greaterEqual, L_index_ok);
437         __ STOP("no virtual index");
438         __ BIND(L_index_ok);
439       }
440 
441       // Note:  The verifier invariants allow us to ignore MemberName.clazz and vmtarget
442       // at this point.  And VerifyMethodHandles has already checked clazz, if needed.
443 
444       // get target Method* & entry point
445       __ lookup_virtual_method(temp1_recv_klass, temp2_index, rbx_method);
446       break;
447     }
448 
449     case vmIntrinsics::_linkToInterface:
450     {
451       // same as TemplateTable::invokeinterface
452       // (minus the CP setup and profiling, with different argument motion)
453       if (VerifyMethodHandles) {
454         verify_ref_kind(_masm, JVM_REF_invokeInterface, member_reg, temp3);
455       }
456 
457       Register temp3_intf = temp3;
458       __ load_heap_oop(temp3_intf, member_clazz);
459       load_klass_from_Class(_masm, temp3_intf);
460       __ verify_klass_ptr(temp3_intf);
461 
462       Register rbx_index = rbx_method;
463       __ access_load_at(T_ADDRESS, IN_HEAP, rbx_index, member_vmindex, noreg, noreg);
464       if (VerifyMethodHandles) {
465         Label L;
466         __ cmpl(rbx_index, 0);
467         __ jcc(Assembler::greaterEqual, L);
468         __ STOP("invalid vtable index for MH.invokeInterface");
469         __ bind(L);
470       }
471 
472       // given intf, index, and recv klass, dispatch to the implementation method
473       __ lookup_interface_method(temp1_recv_klass, temp3_intf,
474                                  // note: next two args must be the same:
475                                  rbx_index, rbx_method,
476                                  temp2,
477                                  L_incompatible_class_change_error);
478       break;
479     }
480 
481     default:
482       fatal("unexpected intrinsic %d: %s", vmIntrinsics::as_int(iid), vmIntrinsics::name_at(iid));
483       break;
484     }
485 
486     // Live at this point:
487     //   rbx_method
488     //   rsi/r13 (if interpreted)
489 
490     // After figuring out which concrete method to call, jump into it.
491     // Note that this works in the interpreter with no data motion.
492     // But the compiled version will require that rcx_recv be shifted out.
493     __ verify_method_ptr(rbx_method);
494     jump_from_method_handle(_masm, rbx_method, temp1, for_compiler_entry);
495 
496     if (iid == vmIntrinsics::_linkToInterface) {
497       __ bind(L_incompatible_class_change_error);
498       __ jump(RuntimeAddress(StubRoutines::throw_IncompatibleClassChangeError_entry()));
499     }
500   }
501 }
502 
503 #ifndef PRODUCT
504 void trace_method_handle_stub(const char* adaptername,
505                               oopDesc* mh,
506                               intptr_t* saved_regs,
507                               intptr_t* entry_sp) {
508   // called as a leaf from native code: do not block the JVM!
509   bool has_mh = (strstr(adaptername, "/static") == NULL &&
510                  strstr(adaptername, "linkTo") == NULL);    // static linkers don't have MH
511   const char* mh_reg_name = has_mh ? "rcx_mh" : "rcx";
512   log_info(methodhandles)("MH %s %s=" PTR_FORMAT " sp=" PTR_FORMAT, adaptername, mh_reg_name, p2i(mh), p2i(entry_sp));
513 
514   LogTarget(Trace, methodhandles) lt;
515   if (lt.is_enabled()) {
516     ResourceMark rm;
517     LogStream ls(lt);
518     ls.print_cr("Registers:");
519     const int saved_regs_count = RegisterImpl::number_of_registers;
520     for (int i = 0; i < saved_regs_count; i++) {
521       Register r = as_Register(i);
522       // The registers are stored in reverse order on the stack (by pusha).
523 #ifdef AMD64
524       assert(RegisterImpl::number_of_registers == 16, "sanity");
525       if (r == rsp) {
526         // rsp is actually not stored by pusha(), compute the old rsp from saved_regs (rsp after pusha): saved_regs + 16 = old rsp
527         ls.print("%3s=" PTR_FORMAT, r->name(), (intptr_t)(&saved_regs[16]));
528       } else {
529         ls.print("%3s=" PTR_FORMAT, r->name(), saved_regs[((saved_regs_count - 1) - i)]);
530       }
531 #else
532       ls.print("%3s=" PTR_FORMAT, r->name(), saved_regs[((saved_regs_count - 1) - i)]);
533 #endif
534       if ((i + 1) % 4 == 0) {
535         ls.cr();
536       } else {
537         ls.print(", ");
538       }
539     }
540     ls.cr();
541 
542     // Note: We want to allow trace_method_handle from any call site.
543     // While trace_method_handle creates a frame, it may be entered
544     // without a PC on the stack top (e.g. not just after a call).
545     // Walking that frame could lead to failures due to that invalid PC.
546     // => carefully detect that frame when doing the stack walking
547 
548     {
549       // dumping last frame with frame::describe
550 
551       JavaThread* p = JavaThread::active();
552 
553       // may not be needed by safer and unexpensive here
554       PreserveExceptionMark pem(Thread::current());
555       FrameValues values;
556 
557       frame cur_frame = os::current_frame();
558 
559       if (cur_frame.fp() != 0) {  // not walkable
560 
561         // Robust search of trace_calling_frame (independent of inlining).
562         // Assumes saved_regs comes from a pusha in the trace_calling_frame.
563         //
564         // We have to start the search from cur_frame, because trace_calling_frame may be it.
565         // It is guaranteed that trace_calling_frame is different from the top frame.
566         // But os::current_frame() does NOT return the top frame: it returns the next frame under it (caller's frame).
567         // (Due to inlining and tail call optimizations, caller's frame doesn't necessarily correspond to the immediate
568         // caller in the source code.)
569         assert(cur_frame.sp() < saved_regs, "registers not saved on stack ?");
570         frame trace_calling_frame = cur_frame;
571         while (trace_calling_frame.fp() < saved_regs) {
572           assert(trace_calling_frame.cb() == NULL, "not a C frame");
573           trace_calling_frame = os::get_sender_for_C_frame(&trace_calling_frame);
574         }
575         assert(trace_calling_frame.sp() < saved_regs, "wrong frame");
576 
577         // safely create a frame and call frame::describe
578         intptr_t *dump_sp = trace_calling_frame.sender_sp();
579         intptr_t *dump_fp = trace_calling_frame.link();
580 
581         if (has_mh) {
582           // The previous definition of walkable may have to be refined
583           // if new call sites cause the next frame constructor to start
584           // failing. Alternatively, frame constructors could be
585           // modified to support the current or future non walkable
586           // frames (but this is more intrusive and is not considered as
587           // part of this RFE, which will instead use a simpler output).
588           frame dump_frame = frame(dump_sp, dump_fp);
589           dump_frame.describe(values, 1);
590         } else {
591           // Stack may not be walkable (invalid PC above FP):
592           // Add descriptions without building a Java frame to avoid issues
593           values.describe(-1, dump_fp, "fp for #1 <not parsed, cannot trust pc>");
594           values.describe(-1, dump_sp, "sp for #1");
595         }
596       }
597       values.describe(-1, entry_sp, "raw top of stack");
598 
599       ls.print_cr("Stack layout:");
600       values.print_on(p, &ls);
601     }
602     if (has_mh && oopDesc::is_oop(mh)) {
603       mh->print_on(&ls);
604       if (java_lang_invoke_MethodHandle::is_instance(mh)) {
605         java_lang_invoke_MethodHandle::form(mh)->print_on(&ls);
606       }
607     }
608   }
609 }
610 
611 // The stub wraps the arguments in a struct on the stack to avoid
612 // dealing with the different calling conventions for passing 6
613 // arguments.
614 struct MethodHandleStubArguments {
615   const char* adaptername;
616   oopDesc* mh;
617   intptr_t* saved_regs;
618   intptr_t* entry_sp;
619 };
620 void trace_method_handle_stub_wrapper(MethodHandleStubArguments* args) {
621   trace_method_handle_stub(args->adaptername,
622                            args->mh,
623                            args->saved_regs,
624                            args->entry_sp);
625 }
626 
627 void MethodHandles::trace_method_handle(MacroAssembler* _masm, const char* adaptername) {
628   if (!log_is_enabled(Info, methodhandles))  return;
629   BLOCK_COMMENT(err_msg("trace_method_handle %s {", adaptername));
630   __ enter();
631   __ andptr(rsp, -16); // align stack if needed for FPU state
632   __ pusha();
633   __ mov(rbx, rsp); // for retrieving saved_regs
634   // Note: saved_regs must be in the entered frame for the
635   // robust stack walking implemented in trace_method_handle_stub.
636 
637   // save FP result, valid at some call sites (adapter_opt_return_float, ...)
638   __ decrement(rsp, 2 * wordSize);
639 #ifdef _LP64
640   __ movdbl(Address(rsp, 0), xmm0);
641 #else
642   if  (UseSSE >= 2) {
643     __ movdbl(Address(rsp, 0), xmm0);
644   } else if (UseSSE == 1) {
645     __ movflt(Address(rsp, 0), xmm0);
646   } else {
647     __ fst_d(Address(rsp, 0));
648   }
649 #endif // LP64
650 
651   // Incoming state:
652   // rcx: method handle
653   //
654   // To avoid calling convention issues, build a record on the stack
655   // and pass the pointer to that instead.
656   __ push(rbp);               // entry_sp (with extra align space)
657   __ push(rbx);               // pusha saved_regs
658   __ push(rcx);               // mh
659   __ push(rcx);               // slot for adaptername
660   __ movptr(Address(rsp, 0), (intptr_t) adaptername);
661   __ super_call_VM_leaf(CAST_FROM_FN_PTR(address, trace_method_handle_stub_wrapper), rsp);
662   __ increment(rsp, sizeof(MethodHandleStubArguments));
663 
664 #ifdef _LP64
665   __ movdbl(xmm0, Address(rsp, 0));
666 #else
667   if  (UseSSE >= 2) {
668     __ movdbl(xmm0, Address(rsp, 0));
669   } else if (UseSSE == 1) {
670     __ movflt(xmm0, Address(rsp, 0));
671   } else {
672     __ fld_d(Address(rsp, 0));
673   }
674 #endif // LP64
675   __ increment(rsp, 2 * wordSize);
676 
677   __ popa();
678   __ leave();
679   BLOCK_COMMENT("} trace_method_handle");
680 }
681 #endif //PRODUCT