1 /*
  2  * Copyright (c) 1997, 2021, Oracle and/or its affiliates. All rights reserved.
  3  * Copyright (c) 2014, Red Hat Inc. All rights reserved.
  4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  5  *
  6  * This code is free software; you can redistribute it and/or modify it
  7  * under the terms of the GNU General Public License version 2 only, as
  8  * published by the Free Software Foundation.
  9  *
 10  * This code is distributed in the hope that it will be useful, but WITHOUT
 11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 13  * version 2 for more details (a copy is included in the LICENSE file that
 14  * accompanied this code).
 15  *
 16  * You should have received a copy of the GNU General Public License version
 17  * 2 along with this work; if not, write to the Free Software Foundation,
 18  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 19  *
 20  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 21  * or visit www.oracle.com if you need additional information or have any
 22  * questions.
 23  *
 24  */
 25 
 26 #include "precompiled.hpp"
 27 #include "asm/macroAssembler.hpp"
 28 #include "classfile/javaClasses.inline.hpp"
 29 #include "classfile/vmClasses.hpp"
 30 #include "interpreter/interpreter.hpp"
 31 #include "interpreter/interpreterRuntime.hpp"
 32 #include "memory/allocation.inline.hpp"
 33 #include "prims/jvmtiExport.hpp"
 34 #include "prims/methodHandles.hpp"
 35 #include "runtime/flags/flagSetting.hpp"
 36 #include "runtime/frame.inline.hpp"
 37 #include "runtime/stubRoutines.hpp"
 38 
 39 #define __ _masm->
 40 
 41 #ifdef PRODUCT
 42 #define BLOCK_COMMENT(str) /* nothing */
 43 #else
 44 #define BLOCK_COMMENT(str) __ block_comment(str)
 45 #endif
 46 
 47 #define BIND(label) bind(label); BLOCK_COMMENT(#label ":")
 48 
 49 void MethodHandles::load_klass_from_Class(MacroAssembler* _masm, Register klass_reg) {
 50   if (VerifyMethodHandles)
 51     verify_klass(_masm, klass_reg, VM_CLASS_ID(java_lang_Class),
 52                  "MH argument is a Class");
 53   __ ldr(klass_reg, Address(klass_reg, java_lang_Class::klass_offset()));
 54 }
 55 
 56 #ifdef ASSERT
 57 static int check_nonzero(const char* xname, int x) {
 58   assert(x != 0, "%s should be nonzero", xname);
 59   return x;
 60 }
 61 #define NONZERO(x) check_nonzero(#x, x)
 62 #else //ASSERT
 63 #define NONZERO(x) (x)
 64 #endif //PRODUCT
 65 
 66 #ifdef ASSERT
 67 void MethodHandles::verify_klass(MacroAssembler* _masm,
 68                                  Register obj, vmClassID klass_id,
 69                                  const char* error_message) {
 70   InstanceKlass** klass_addr = vmClasses::klass_addr_at(klass_id);
 71   Klass* klass = vmClasses::klass_at(klass_id);
 72   Register temp = rscratch2;
 73   Register temp2 = rscratch1; // used by MacroAssembler::cmpptr
 74   Label L_ok, L_bad;
 75   BLOCK_COMMENT("verify_klass {");
 76   __ verify_oop(obj);
 77   __ cbz(obj, L_bad);
 78   __ push(RegSet::of(temp, temp2), sp);
 79   __ load_klass(temp, obj);
 80   __ cmpptr(temp, ExternalAddress((address) klass_addr));
 81   __ br(Assembler::EQ, L_ok);
 82   intptr_t super_check_offset = klass->super_check_offset();
 83   __ ldr(temp, Address(temp, super_check_offset));
 84   __ cmpptr(temp, ExternalAddress((address) klass_addr));
 85   __ br(Assembler::EQ, L_ok);
 86   __ pop(RegSet::of(temp, temp2), sp);
 87   __ bind(L_bad);
 88   __ stop(error_message);
 89   __ BIND(L_ok);
 90   __ pop(RegSet::of(temp, temp2), sp);
 91   BLOCK_COMMENT("} verify_klass");
 92 }
 93 
 94 void MethodHandles::verify_ref_kind(MacroAssembler* _masm, int ref_kind, Register member_reg, Register temp) {  }
 95 
 96 #endif //ASSERT
 97 
 98 void MethodHandles::jump_from_method_handle(MacroAssembler* _masm, Register method, Register temp,
 99                                             bool for_compiler_entry) {
100   assert(method == rmethod, "interpreter calling convention");
101   Label L_no_such_method;
102   __ cbz(rmethod, L_no_such_method);
103   __ verify_method_ptr(method);
104 
105   if (!for_compiler_entry && JvmtiExport::can_post_interpreter_events()) {
106     Label run_compiled_code;
107     // JVMTI events, such as single-stepping, are implemented partly by avoiding running
108     // compiled code in threads for which the event is enabled.  Check here for
109     // interp_only_mode if these events CAN be enabled.
110 
111     __ ldrw(rscratch1, Address(rthread, JavaThread::interp_only_mode_offset()));
112     __ cbzw(rscratch1, run_compiled_code);
113     __ ldr(rscratch1, Address(method, Method::interpreter_entry_offset()));
114     __ br(rscratch1);
115     __ BIND(run_compiled_code);
116   }
117 
118   // The following jump might pass an inline type argument that was erased to Object as oop to a
119   // callee that expects inline type arguments to be passed as fields. We need to call the compiled
120   // value entry (_code->inline_entry_point() or _adapter->c2i_inline_entry()) which will take care
121   // of translating between the calling conventions.
122   const ByteSize entry_offset = for_compiler_entry ? Method::from_compiled_inline_offset() :
123                                                      Method::from_interpreted_offset();
124   __ ldr(rscratch1,Address(method, entry_offset));
125   __ br(rscratch1);
126   __ bind(L_no_such_method);
127   __ far_jump(RuntimeAddress(StubRoutines::throw_AbstractMethodError_entry()));
128 }
129 
130 void MethodHandles::jump_to_lambda_form(MacroAssembler* _masm,
131                                         Register recv, Register method_temp,
132                                         Register temp2,
133                                         bool for_compiler_entry) {
134   BLOCK_COMMENT("jump_to_lambda_form {");
135   // This is the initial entry point of a lazy method handle.
136   // After type checking, it picks up the invoker from the LambdaForm.
137   assert_different_registers(recv, method_temp, temp2);
138   assert(recv != noreg, "required register");
139   assert(method_temp == rmethod, "required register for loading method");
140 
141   // Load the invoker, as MH -> MH.form -> LF.vmentry
142   __ verify_oop(recv);
143   __ load_heap_oop(method_temp, Address(recv, NONZERO(java_lang_invoke_MethodHandle::form_offset())), temp2);
144   __ verify_oop(method_temp);
145   __ load_heap_oop(method_temp, Address(method_temp, NONZERO(java_lang_invoke_LambdaForm::vmentry_offset())), temp2);
146   __ verify_oop(method_temp);
147   __ load_heap_oop(method_temp, Address(method_temp, NONZERO(java_lang_invoke_MemberName::method_offset())), temp2);
148   __ verify_oop(method_temp);
149   __ access_load_at(T_ADDRESS, IN_HEAP, method_temp, Address(method_temp, NONZERO(java_lang_invoke_ResolvedMethodName::vmtarget_offset())), noreg, noreg);
150 
151   if (VerifyMethodHandles && !for_compiler_entry) {
152     // make sure recv is already on stack
153     __ ldr(temp2, Address(method_temp, Method::const_offset()));
154     __ load_sized_value(temp2,
155                         Address(temp2, ConstMethod::size_of_parameters_offset()),
156                         sizeof(u2), /*is_signed*/ false);
157     // assert(sizeof(u2) == sizeof(Method::_size_of_parameters), "");
158     Label L;
159     __ ldr(rscratch1, __ argument_address(temp2, -1));
160     __ cmpoop(recv, rscratch1);
161     __ br(Assembler::EQ, L);
162     __ ldr(r0, __ argument_address(temp2, -1));
163     __ hlt(0);
164     __ BIND(L);
165   }
166 
167   jump_from_method_handle(_masm, method_temp, temp2, for_compiler_entry);
168   BLOCK_COMMENT("} jump_to_lambda_form");
169 }
170 
171 // Code generation
172 address MethodHandles::generate_method_handle_interpreter_entry(MacroAssembler* _masm,
173                                                                 vmIntrinsics::ID iid) {
174   const bool not_for_compiler_entry = false;  // this is the interpreter entry
175   assert(is_signature_polymorphic(iid), "expected invoke iid");
176   if (iid == vmIntrinsics::_invokeGeneric ||
177       iid == vmIntrinsics::_compiledLambdaForm) {
178     // Perhaps surprisingly, the symbolic references visible to Java are not directly used.
179     // They are linked to Java-generated adapters via MethodHandleNatives.linkMethod.
180     // They all allow an appendix argument.
181     __ hlt(0);           // empty stubs make SG sick
182     return NULL;
183   }
184 
185   // No need in interpreter entry for linkToNative for now.
186   // Interpreter calls compiled entry through i2c.
187   if (iid == vmIntrinsics::_linkToNative) {
188     __ hlt(0);
189     return NULL;
190   }
191 
192   // r13: sender SP (must preserve; see prepare_to_jump_from_interpreted)
193   // rmethod: Method*
194   // r3: argument locator (parameter slot count, added to rsp)
195   // r1: used as temp to hold mh or receiver
196   // r0, r11: garbage temps, blown away
197   Register argp   = r3;   // argument list ptr, live on error paths
198   Register temp   = r0;
199   Register mh     = r1;   // MH receiver; dies quickly and is recycled
200 
201   // here's where control starts out:
202   __ align(CodeEntryAlignment);
203   address entry_point = __ pc();
204 
205   if (VerifyMethodHandles) {
206     assert(Method::intrinsic_id_size_in_bytes() == 2, "assuming Method::_intrinsic_id is u2");
207 
208     Label L;
209     BLOCK_COMMENT("verify_intrinsic_id {");
210     __ ldrh(rscratch1, Address(rmethod, Method::intrinsic_id_offset_in_bytes()));
211     __ subs(zr, rscratch1, (int) iid);
212     __ br(Assembler::EQ, L);
213     if (iid == vmIntrinsics::_linkToVirtual ||
214         iid == vmIntrinsics::_linkToSpecial) {
215       // could do this for all kinds, but would explode assembly code size
216       trace_method_handle(_masm, "bad Method*::intrinsic_id");
217     }
218     __ hlt(0);
219     __ bind(L);
220     BLOCK_COMMENT("} verify_intrinsic_id");
221   }
222 
223   // First task:  Find out how big the argument list is.
224   Address r3_first_arg_addr;
225   int ref_kind = signature_polymorphic_intrinsic_ref_kind(iid);
226   assert(ref_kind != 0 || iid == vmIntrinsics::_invokeBasic, "must be _invokeBasic or a linkTo intrinsic");
227   if (ref_kind == 0 || MethodHandles::ref_kind_has_receiver(ref_kind)) {
228     __ ldr(argp, Address(rmethod, Method::const_offset()));
229     __ load_sized_value(argp,
230                         Address(argp, ConstMethod::size_of_parameters_offset()),
231                         sizeof(u2), /*is_signed*/ false);
232     // assert(sizeof(u2) == sizeof(Method::_size_of_parameters), "");
233     r3_first_arg_addr = __ argument_address(argp, -1);
234   } else {
235     DEBUG_ONLY(argp = noreg);
236   }
237 
238   if (!is_signature_polymorphic_static(iid)) {
239     __ ldr(mh, r3_first_arg_addr);
240     DEBUG_ONLY(argp = noreg);
241   }
242 
243   // r3_first_arg_addr is live!
244 
245   trace_method_handle_interpreter_entry(_masm, iid);
246   if (iid == vmIntrinsics::_invokeBasic) {
247     generate_method_handle_dispatch(_masm, iid, mh, noreg, not_for_compiler_entry);
248 
249   } else {
250     // Adjust argument list by popping the trailing MemberName argument.
251     Register recv = noreg;
252     if (MethodHandles::ref_kind_has_receiver(ref_kind)) {
253       // Load the receiver (not the MH; the actual MemberName's receiver) up from the interpreter stack.
254       __ ldr(recv = r2, r3_first_arg_addr);
255     }
256     DEBUG_ONLY(argp = noreg);
257     Register rmember = rmethod;  // MemberName ptr; incoming method ptr is dead now
258     __ pop(rmember);             // extract last argument
259     generate_method_handle_dispatch(_masm, iid, recv, rmember, not_for_compiler_entry);
260   }
261 
262   return entry_point;
263 }
264 
265 
266 void MethodHandles::generate_method_handle_dispatch(MacroAssembler* _masm,
267                                                     vmIntrinsics::ID iid,
268                                                     Register receiver_reg,
269                                                     Register member_reg,
270                                                     bool for_compiler_entry) {
271   assert(is_signature_polymorphic(iid), "expected invoke iid");
272   // temps used in this code are not used in *either* compiled or interpreted calling sequences
273   Register temp1 = r10;
274   Register temp2 = r11;
275   Register temp3 = r14;  // r13 is live by this point: it contains the sender SP
276   if (for_compiler_entry) {
277     assert(receiver_reg == (iid == vmIntrinsics::_linkToStatic ? noreg : j_rarg0), "only valid assignment");
278     assert_different_registers(temp1,        j_rarg0, j_rarg1, j_rarg2, j_rarg3, j_rarg4, j_rarg5, j_rarg6, j_rarg7);
279     assert_different_registers(temp2,        j_rarg0, j_rarg1, j_rarg2, j_rarg3, j_rarg4, j_rarg5, j_rarg6, j_rarg7);
280     assert_different_registers(temp3,        j_rarg0, j_rarg1, j_rarg2, j_rarg3, j_rarg4, j_rarg5, j_rarg6, j_rarg7);
281   }
282 
283   assert_different_registers(temp1, temp2, temp3, receiver_reg);
284   assert_different_registers(temp1, temp2, temp3, member_reg);
285 
286   if (iid == vmIntrinsics::_invokeBasic || iid == vmIntrinsics::_linkToNative) {
287     if (iid == vmIntrinsics::_linkToNative) {
288       assert(for_compiler_entry, "only compiler entry is supported");
289     }
290     // indirect through MH.form.vmentry.vmtarget
291     jump_to_lambda_form(_masm, receiver_reg, rmethod, temp1, for_compiler_entry);
292 
293   } else {
294     // The method is a member invoker used by direct method handles.
295     if (VerifyMethodHandles) {
296       // make sure the trailing argument really is a MemberName (caller responsibility)
297       verify_klass(_masm, member_reg, VM_CLASS_ID(java_lang_invoke_MemberName),
298                    "MemberName required for invokeVirtual etc.");
299     }
300 
301     Address member_clazz(    member_reg, NONZERO(java_lang_invoke_MemberName::clazz_offset()));
302     Address member_vmindex(  member_reg, NONZERO(java_lang_invoke_MemberName::vmindex_offset()));
303     Address member_vmtarget( member_reg, NONZERO(java_lang_invoke_MemberName::method_offset()));
304     Address vmtarget_method( rmethod, NONZERO(java_lang_invoke_ResolvedMethodName::vmtarget_offset()));
305 
306     Register temp1_recv_klass = temp1;
307     if (iid != vmIntrinsics::_linkToStatic) {
308       __ verify_oop(receiver_reg);
309       if (iid == vmIntrinsics::_linkToSpecial) {
310         // Don't actually load the klass; just null-check the receiver.
311         __ null_check(receiver_reg);
312       } else {
313         // load receiver klass itself
314         __ null_check(receiver_reg, oopDesc::klass_offset_in_bytes());
315         __ load_klass(temp1_recv_klass, receiver_reg);
316         __ verify_klass_ptr(temp1_recv_klass);
317       }
318       BLOCK_COMMENT("check_receiver {");
319       // The receiver for the MemberName must be in receiver_reg.
320       // Check the receiver against the MemberName.clazz
321       if (VerifyMethodHandles && iid == vmIntrinsics::_linkToSpecial) {
322         // Did not load it above...
323         __ load_klass(temp1_recv_klass, receiver_reg);
324         __ verify_klass_ptr(temp1_recv_klass);
325       }
326       if (VerifyMethodHandles && iid != vmIntrinsics::_linkToInterface) {
327         Label L_ok;
328         Register temp2_defc = temp2;
329         __ load_heap_oop(temp2_defc, member_clazz, temp3);
330         load_klass_from_Class(_masm, temp2_defc);
331         __ verify_klass_ptr(temp2_defc);
332         __ check_klass_subtype(temp1_recv_klass, temp2_defc, temp3, L_ok);
333         // If we get here, the type check failed!
334         __ hlt(0);
335         // __ STOP("receiver class disagrees with MemberName.clazz");
336         __ bind(L_ok);
337       }
338       BLOCK_COMMENT("} check_receiver");
339     }
340     if (iid == vmIntrinsics::_linkToSpecial ||
341         iid == vmIntrinsics::_linkToStatic) {
342       DEBUG_ONLY(temp1_recv_klass = noreg);  // these guys didn't load the recv_klass
343     }
344 
345     // Live registers at this point:
346     //  member_reg - MemberName that was the trailing argument
347     //  temp1_recv_klass - klass of stacked receiver, if needed
348     //  r13 - interpreter linkage (if interpreted)  ??? FIXME
349     //  r1 ... r0 - compiler arguments (if compiled)
350 
351     Label L_incompatible_class_change_error;
352     switch (iid) {
353     case vmIntrinsics::_linkToSpecial:
354       if (VerifyMethodHandles) {
355         verify_ref_kind(_masm, JVM_REF_invokeSpecial, member_reg, temp3);
356       }
357       __ load_heap_oop(rmethod, member_vmtarget);
358       __ access_load_at(T_ADDRESS, IN_HEAP, rmethod, vmtarget_method, noreg, noreg);
359       break;
360 
361     case vmIntrinsics::_linkToStatic:
362       if (VerifyMethodHandles) {
363         verify_ref_kind(_masm, JVM_REF_invokeStatic, member_reg, temp3);
364       }
365       __ load_heap_oop(rmethod, member_vmtarget);
366       __ access_load_at(T_ADDRESS, IN_HEAP, rmethod, vmtarget_method, noreg, noreg);
367       break;
368 
369     case vmIntrinsics::_linkToVirtual:
370     {
371       // same as TemplateTable::invokevirtual,
372       // minus the CP setup and profiling:
373 
374       if (VerifyMethodHandles) {
375         verify_ref_kind(_masm, JVM_REF_invokeVirtual, member_reg, temp3);
376       }
377 
378       // pick out the vtable index from the MemberName, and then we can discard it:
379       Register temp2_index = temp2;
380       __ access_load_at(T_ADDRESS, IN_HEAP, temp2_index, member_vmindex, noreg, noreg);
381 
382       if (VerifyMethodHandles) {
383         Label L_index_ok;
384         __ cmpw(temp2_index, 0U);
385         __ br(Assembler::GE, L_index_ok);
386         __ hlt(0);
387         __ BIND(L_index_ok);
388       }
389 
390       // Note:  The verifier invariants allow us to ignore MemberName.clazz and vmtarget
391       // at this point.  And VerifyMethodHandles has already checked clazz, if needed.
392 
393       // get target Method* & entry point
394       __ lookup_virtual_method(temp1_recv_klass, temp2_index, rmethod);
395       break;
396     }
397 
398     case vmIntrinsics::_linkToInterface:
399     {
400       // same as TemplateTable::invokeinterface
401       // (minus the CP setup and profiling, with different argument motion)
402       if (VerifyMethodHandles) {
403         verify_ref_kind(_masm, JVM_REF_invokeInterface, member_reg, temp3);
404       }
405 
406       Register temp3_intf = temp3;
407       __ load_heap_oop(temp3_intf, member_clazz);
408       load_klass_from_Class(_masm, temp3_intf);
409       __ verify_klass_ptr(temp3_intf);
410 
411       Register rindex = rmethod;
412       __ access_load_at(T_ADDRESS, IN_HEAP, rindex, member_vmindex, noreg, noreg);
413       if (VerifyMethodHandles) {
414         Label L;
415         __ cmpw(rindex, 0U);
416         __ br(Assembler::GE, L);
417         __ hlt(0);
418         __ bind(L);
419       }
420 
421       // given intf, index, and recv klass, dispatch to the implementation method
422       __ lookup_interface_method(temp1_recv_klass, temp3_intf,
423                                  // note: next two args must be the same:
424                                  rindex, rmethod,
425                                  temp2,
426                                  L_incompatible_class_change_error);
427       break;
428     }
429 
430     default:
431       fatal("unexpected intrinsic %d: %s", vmIntrinsics::as_int(iid), vmIntrinsics::name_at(iid));
432       break;
433     }
434 
435     // live at this point:  rmethod, r13 (if interpreted)
436 
437     // After figuring out which concrete method to call, jump into it.
438     // Note that this works in the interpreter with no data motion.
439     // But the compiled version will require that r2_recv be shifted out.
440     __ verify_method_ptr(rmethod);
441     jump_from_method_handle(_masm, rmethod, temp1, for_compiler_entry);
442     if (iid == vmIntrinsics::_linkToInterface) {
443       __ bind(L_incompatible_class_change_error);
444       __ far_jump(RuntimeAddress(StubRoutines::throw_IncompatibleClassChangeError_entry()));
445     }
446   }
447 }
448 
449 #ifndef PRODUCT
450 void trace_method_handle_stub(const char* adaptername,
451                               oopDesc* mh,
452                               intptr_t* saved_regs,
453                               intptr_t* entry_sp) {  }
454 
455 // The stub wraps the arguments in a struct on the stack to avoid
456 // dealing with the different calling conventions for passing 6
457 // arguments.
458 struct MethodHandleStubArguments {
459   const char* adaptername;
460   oopDesc* mh;
461   intptr_t* saved_regs;
462   intptr_t* entry_sp;
463 };
464 void trace_method_handle_stub_wrapper(MethodHandleStubArguments* args) {  }
465 
466 void MethodHandles::trace_method_handle(MacroAssembler* _masm, const char* adaptername) {  }
467 #endif //PRODUCT