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 /*

  * Copyright (c) 1997, 2017, Oracle and/or its affiliates. All rights reserved.

  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

  *

  * This code is free software; you can redistribute it and/or modify it

  * under the terms of the GNU General Public License version 2 only, as

  * published by the Free Software Foundation.

  *

  * This code is distributed in the hope that it will be useful, but WITHOUT

  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

  * version 2 for more details (a copy is included in the LICENSE file that

  * accompanied this code).

  *

  * You should have received a copy of the GNU General Public License version

  * 2 along with this work; if not, write to the Free Software Foundation,

  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

  *

  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

  * or visit www.oracle.com if you need additional information or have any

  * questions.

  *

  */

 #include "precompiled.hpp"

 #include "asm/macroAssembler.hpp"

 #include "code/vtableStubs.hpp"

 #include "interp_masm_x86.hpp"

 #include "memory/resourceArea.hpp"

 #include "oops/compiledICHolder.hpp"

 #include "oops/instanceKlass.hpp"

 #include "oops/klassVtable.hpp"

 #include "runtime/sharedRuntime.hpp"

 #include "vmreg_x86.inline.hpp"

 #ifdef COMPILER2

 #include "opto/runtime.hpp"

 #endif

 // machine-dependent part of VtableStubs: create VtableStub of correct size and

 // initialize its code

 #define __ masm->

 #ifndef PRODUCT

 extern "C" void bad_compiled_vtable_index(JavaThread* thread, oop receiver, int index);

 #endif

 // These stubs are used by the compiler only.

 // Argument registers, which must be preserved:

 //   rcx - receiver (always first argument)

 //   rdx - second argument (if any)

 // Other registers that might be usable:

 //   rax - inline cache register (is interface for itable stub)

 //   rbx - method (used when calling out to interpreter)

 // Available now, but may become callee-save at some point:

 //   rsi, rdi

 // Note that rax and rdx are also used for return values.

 //

 VtableStub* VtableStubs::create_vtable_stub(int vtable_index) {

   const int i486_code_length = VtableStub::pd_code_size_limit(true);

   VtableStub* s = new(i486_code_length) VtableStub(true, vtable_index);

   // Can be NULL if there is no free space in the code cache.

   if (s == NULL) {

     return NULL;

   }

   ResourceMark rm;

   CodeBuffer cb(s->entry_point(), i486_code_length);

   MacroAssembler* masm = new MacroAssembler(&cb);

 #ifndef PRODUCT

   if (CountCompiledCalls) {

     __ incrementl(ExternalAddress((address) SharedRuntime::nof_megamorphic_calls_addr()));

   }

 #endif /* PRODUCT */

   // get receiver (need to skip return address on top of stack)

   assert(VtableStub::receiver_location() == rcx->as_VMReg(), "receiver expected in rcx");

   // get receiver klass

   address npe_addr = __ pc();

   __ movptr(rax, Address(rcx, oopDesc::klass_offset_in_bytes()));

 #ifndef PRODUCT

   if (DebugVtables) {

     Label L;

     // check offset vs vtable length

     __ cmpl(Address(rax, InstanceKlass::vtable_length_offset()*wordSize), vtable_index*vtableEntry::size());

     __ jcc(Assembler::greater, L);

     __ movl(rbx, vtable_index);

     __ call_VM(noreg, CAST_FROM_FN_PTR(address, bad_compiled_vtable_index), rcx, rbx);

     __ bind(L);

   }

 #endif // PRODUCT

   const Register method = rbx;

   // load Method* and target address

   __ lookup_virtual_method(rax, vtable_index, method);

   if (DebugVtables) {

     Label L;

     __ cmpptr(method, (int32_t)NULL_WORD);

     __ jcc(Assembler::equal, L);

     __ cmpptr(Address(method, Method::from_compiled_offset()), (int32_t)NULL_WORD);

     __ jcc(Assembler::notZero, L);

     __ stop("Vtable entry is NULL");

     __ bind(L);

   }

   // rax,: receiver klass

   // method (rbx): Method*

   // rcx: receiver

   address ame_addr = __ pc();

   __ jmp( Address(method, Method::from_compiled_offset()));

   masm->flush();

   if (PrintMiscellaneous && (WizardMode || Verbose)) {

     tty->print_cr("vtable #%d at "PTR_FORMAT"[%d] left over: %d",

                   vtable_index, p2i(s->entry_point()),

                   (int)(s->code_end() - s->entry_point()),

                   (int)(s->code_end() - __ pc()));

   }

   guarantee(__ pc() <= s->code_end(), "overflowed buffer");

   // shut the door on sizing bugs

   int slop = 3;  // 32-bit offset is this much larger than an 8-bit one

   assert(vtable_index > 10 || __ pc() + slop <= s->code_end(), "room for 32-bit offset");

   s->set_exception_points(npe_addr, ame_addr);

   return s;

 }

 VtableStub* VtableStubs::create_itable_stub(int itable_index) {

   // Note well: pd_code_size_limit is the absolute minimum we can get away with.  If you

   //            add code here, bump the code stub size returned by pd_code_size_limit!

   const int i486_code_length = VtableStub::pd_code_size_limit(false);

   VtableStub* s = new(i486_code_length) VtableStub(false, itable_index);

   // Can be NULL if there is no free space in the code cache.

   if (s == NULL) {

     return NULL;

   }

   ResourceMark rm;

   CodeBuffer cb(s->entry_point(), i486_code_length);

   MacroAssembler* masm = new MacroAssembler(&cb);

   // Entry arguments:

   //  rax: CompiledICHolder

   //  rcx: Receiver

 #ifndef PRODUCT

   if (CountCompiledCalls) {

     __ incrementl(ExternalAddress((address) SharedRuntime::nof_megamorphic_calls_addr()));

   }

 #endif /* PRODUCT */

   // Most registers are in use; we'll use rax, rbx, rsi, rdi

   // (If we need to make rsi, rdi callee-save, do a push/pop here.)

   const Register recv_klass_reg     = rsi;

   const Register holder_klass_reg   = rax; // declaring interface klass (DECC)

   const Register resolved_klass_reg = rbx; // resolved interface klass (REFC)

   const Register temp_reg           = rdi;

   const Register icholder_reg = rax;

   __ movptr(resolved_klass_reg, Address(icholder_reg, CompiledICHolder::holder_klass_offset()));

   __ movptr(holder_klass_reg,   Address(icholder_reg, CompiledICHolder::holder_metadata_offset()));

   Label L_no_such_interface;

   // get receiver klass (also an implicit null-check)

   address npe_addr = __ pc();

   assert(VtableStub::receiver_location() ==  rcx->as_VMReg(), "receiver expected in  rcx");

   __ load_klass(recv_klass_reg, rcx);

   // Receiver subtype check against REFC.

   // Destroys recv_klass_reg value.

   __ lookup_interface_method(// inputs: rec. class, interface

                              recv_klass_reg, resolved_klass_reg, noreg,

                              // outputs:  scan temp. reg1, scan temp. reg2

                              recv_klass_reg, temp_reg,

                              L_no_such_interface,

                              /*return_method=*/false);

   // Get selected method from declaring class and itable index

   const Register method = rbx;

   __ load_klass(recv_klass_reg, rcx); // restore recv_klass_reg

   __ lookup_interface_method(// inputs: rec. class, interface, itable index

                              recv_klass_reg, holder_klass_reg, itable_index,

                              // outputs: method, scan temp. reg

                              method, temp_reg,

                              L_no_such_interface);

   // method (rbx): Method*

   // rcx: receiver

 #ifdef ASSERT

   if (DebugVtables) {

       Label L1;

       __ cmpptr(method, (int32_t)NULL_WORD);

       __ jcc(Assembler::equal, L1);

       __ cmpptr(Address(method, Method::from_compiled_offset()), (int32_t)NULL_WORD);

       __ jcc(Assembler::notZero, L1);

       __ stop("Method* is null");

       __ bind(L1);

     }

 #endif // ASSERT

   address ame_addr = __ pc();

   __ jmp(Address(method, Method::from_compiled_offset()));

   __ bind(L_no_such_interface);

   __ jump(RuntimeAddress(StubRoutines::throw_IncompatibleClassChangeError_entry()));

   __ flush();

   if (PrintMiscellaneous && (WizardMode || Verbose)) {

     tty->print_cr("itable #%d at "PTR_FORMAT"[%d] left over: %d",

                   itable_index, p2i(s->entry_point()),

                   (int)(s->code_end() - s->entry_point()),

                   (int)(s->code_end() - __ pc()));

   }

   guarantee(__ pc() <= s->code_end(), "overflowed buffer");

   // shut the door on sizing bugs

   int slop = 3;  // 32-bit offset is this much larger than an 8-bit one

   assert(itable_index > 10 || __ pc() + slop <= s->code_end(), "room for 32-bit offset");

   s->set_exception_points(npe_addr, ame_addr);

   return s;

 }

 int VtableStub::pd_code_size_limit(bool is_vtable_stub) {

   if (is_vtable_stub) {

     // Vtable stub size

     return (DebugVtables ? 210 : 16) + (CountCompiledCalls ? 6 : 0);

   } else {

     // Itable stub size

     return (DebugVtables ? 256 : 116) + (CountCompiledCalls ? 6 : 0);

   }

   // In order to tune these parameters, run the JVM with VM options

   // +PrintMiscellaneous and +WizardMode to see information about

   // actual itable stubs.  Look for lines like this:

   //   itable #1 at 0x5551212[65] left over: 3

   // Reduce the constants so that the "left over" number is >=3

   // for the common cases.

   // Do not aim at a left-over number of zero, because a

   // large vtable or itable index (> 16) will require a 32-bit

   // immediate displacement instead of an 8-bit one.

   //

   // The JVM98 app. _202_jess has a megamorphic interface call.

   // The itable code looks like this:

   // Decoding VtableStub itbl[1]@1

   //   mov    0x4(%ecx),%esi

   //   mov    0xe8(%esi),%edi

   //   lea    0x130(%esi,%edi,4),%edi

   //   add    $0x7,%edi

   //   and    $0xfffffff8,%edi

   //   lea    0x4(%esi),%esi

   //   mov    (%edi),%ebx

   //   cmp    %ebx,%eax

   //   je     success

   // loop:

   //   test   %ebx,%ebx

   //   je     throw_icce

   //   add    $0x8,%edi

   //   mov    (%edi),%ebx

   //   cmp    %ebx,%eax

   //   jne    loop

   // success:

   //   mov    0x4(%edi),%edi

   //   mov    (%esi,%edi,1),%ebx

   //   jmp    *0x44(%ebx)

   // throw_icce:

   //   jmp    throw_ICCE_entry

 }

 int VtableStub::pd_code_alignment() {

   return wordSize;

 }