/*

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

 * Copyright (c) 2014, Red Hat Inc. 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 "classfile/javaClasses.inline.hpp"

#include "interpreter/interpreter.hpp"

#include "interpreter/interpreterRuntime.hpp"

#include "memory/allocation.inline.hpp"

#include "prims/methodHandles.hpp"

#define __ _masm->

#ifdef PRODUCT

#define BLOCK_COMMENT(str) /* nothing */

#else

#define BLOCK_COMMENT(str) __ block_comment(str)

#endif

#define BIND(label) bind(label); BLOCK_COMMENT(#label ":")

void MethodHandles::load_klass_from_Class(MacroAssembler* _masm, Register klass_reg) {

  if (VerifyMethodHandles)

    verify_klass(_masm, klass_reg, SystemDictionary::WK_KLASS_ENUM_NAME(java_lang_Class),

                 "MH argument is a Class");

  __ ldr(klass_reg, Address(klass_reg, java_lang_Class::klass_offset_in_bytes()));

}

#ifdef ASSERT

static int check_nonzero(const char* xname, int x) {

  assert(x != 0, "%s should be nonzero", xname);

  return x;

}

#define NONZERO(x) check_nonzero(#x, x)

#else //ASSERT

#define NONZERO(x) (x)

#endif //PRODUCT

#ifdef ASSERT

void MethodHandles::verify_klass(MacroAssembler* _masm,

                                 Register obj, SystemDictionary::WKID klass_id,

                                 const char* error_message) {

  InstanceKlass** klass_addr = SystemDictionary::well_known_klass_addr(klass_id);

  Klass* klass = SystemDictionary::well_known_klass(klass_id);

  Register temp = rscratch2;

  Register temp2 = rscratch1; // used by MacroAssembler::cmpptr

  Label L_ok, L_bad;

  BLOCK_COMMENT("verify_klass {");

  __ verify_oop(obj);

  __ cbz(obj, L_bad);

  __ push(RegSet::of(temp, temp2), sp);

  __ load_klass(temp, obj);

  __ cmpptr(temp, ExternalAddress((address) klass_addr));

  __ br(Assembler::EQ, L_ok);

  intptr_t super_check_offset = klass->super_check_offset();

  __ ldr(temp, Address(temp, super_check_offset));

  __ cmpptr(temp, ExternalAddress((address) klass_addr));

  __ br(Assembler::EQ, L_ok);

  __ pop(RegSet::of(temp, temp2), sp);

  __ bind(L_bad);

  __ stop(error_message);

  __ BIND(L_ok);

  __ pop(RegSet::of(temp, temp2), sp);

  BLOCK_COMMENT("} verify_klass");

}

void MethodHandles::verify_ref_kind(MacroAssembler* _masm, int ref_kind, Register member_reg, Register temp) {  }

#endif //ASSERT

void MethodHandles::jump_from_method_handle(MacroAssembler* _masm, Register method, Register temp,

                                            bool for_compiler_entry) {

  assert(method == rmethod, "interpreter calling convention");

  Label L_no_such_method;

  __ cbz(rmethod, L_no_such_method);

  __ verify_method_ptr(method);

  if (!for_compiler_entry && JvmtiExport::can_post_interpreter_events()) {

    Label run_compiled_code;

    // JVMTI events, such as single-stepping, are implemented partly by avoiding running

    // compiled code in threads for which the event is enabled.  Check here for

    // interp_only_mode if these events CAN be enabled.

    __ ldrb(rscratch1, Address(rthread, JavaThread::interp_only_mode_offset()));

    __ cbnz(rscratch1, run_compiled_code);

    __ ldr(rscratch1, Address(method, Method::interpreter_entry_offset()));

    __ br(rscratch1);

    __ BIND(run_compiled_code);

  }

  const ByteSize entry_offset = for_compiler_entry ? Method::from_compiled_offset() :

                                                     Method::from_interpreted_offset();

  __ ldr(rscratch1,Address(method, entry_offset));

  __ br(rscratch1);

  __ bind(L_no_such_method);

  __ far_jump(RuntimeAddress(StubRoutines::throw_AbstractMethodError_entry()));

}

void MethodHandles::jump_to_lambda_form(MacroAssembler* _masm,

                                        Register recv, Register method_temp,

                                        Register temp2,

                                        bool for_compiler_entry) {

  BLOCK_COMMENT("jump_to_lambda_form {");

  // This is the initial entry point of a lazy method handle.

  // After type checking, it picks up the invoker from the LambdaForm.

  assert_different_registers(recv, method_temp, temp2);

  assert(recv != noreg, "required register");

  assert(method_temp == rmethod, "required register for loading method");

  //NOT_PRODUCT({ FlagSetting fs(TraceMethodHandles, true); trace_method_handle(_masm, "LZMH"); });

  // Load the invoker, as MH -> MH.form -> LF.vmentry

  __ verify_oop(recv);

  __ load_heap_oop(method_temp, Address(recv, NONZERO(java_lang_invoke_MethodHandle::form_offset_in_bytes())));

  __ verify_oop(method_temp);

  __ load_heap_oop(method_temp, Address(method_temp, NONZERO(java_lang_invoke_LambdaForm::vmentry_offset_in_bytes())));

  __ verify_oop(method_temp);

  if (VerifyMethodHandles && !for_compiler_entry) {

    // make sure recv is already on stack

    __ ldr(temp2, Address(method_temp, Method::const_offset()));

    __ load_sized_value(temp2,

                        Address(temp2, ConstMethod::size_of_parameters_offset()),

                        sizeof(u2), /*is_signed*/ false);

    // assert(sizeof(u2) == sizeof(Method::_size_of_parameters), "");

    Label L;

    __ ldr(rscratch1, __ argument_address(temp2, -1));

    __ cmp(recv, rscratch1);

    __ br(Assembler::EQ, L);

    __ ldr(r0, __ argument_address(temp2, -1));

    __ hlt(0);

    __ BIND(L);

  }

  jump_from_method_handle(_masm, method_temp, temp2, for_compiler_entry);

  BLOCK_COMMENT("} jump_to_lambda_form");

}

// Code generation

address MethodHandles::generate_method_handle_interpreter_entry(MacroAssembler* _masm,

                                                                vmIntrinsics::ID iid) {

  const bool not_for_compiler_entry = false;  // this is the interpreter entry

  assert(is_signature_polymorphic(iid), "expected invoke iid");

  if (iid == vmIntrinsics::_invokeGeneric ||

      iid == vmIntrinsics::_compiledLambdaForm) {

    // Perhaps surprisingly, the symbolic references visible to Java are not directly used.

    // They are linked to Java-generated adapters via MethodHandleNatives.linkMethod.

    // They all allow an appendix argument.

    __ hlt(0);           // empty stubs make SG sick

    return NULL;

  }

  // r13: sender SP (must preserve; see prepare_to_jump_from_interpreted)

  // rmethod: Method*

  // r3: argument locator (parameter slot count, added to rsp)

  // r1: used as temp to hold mh or receiver

  // r0, r11: garbage temps, blown away

  Register argp   = r3;   // argument list ptr, live on error paths

  Register temp   = r0;

  Register mh     = r1;   // MH receiver; dies quickly and is recycled

  // here's where control starts out:

  __ align(CodeEntryAlignment);

  address entry_point = __ pc();

  if (VerifyMethodHandles) {

    assert(Method::intrinsic_id_size_in_bytes() == 2, "assuming Method::_intrinsic_id is u2");

    Label L;

    BLOCK_COMMENT("verify_intrinsic_id {");

    __ ldrh(rscratch1, Address(rmethod, Method::intrinsic_id_offset_in_bytes()));

    __ cmp(rscratch1, (int) iid);

    __ br(Assembler::EQ, L);

    if (iid == vmIntrinsics::_linkToVirtual ||

        iid == vmIntrinsics::_linkToSpecial) {

      // could do this for all kinds, but would explode assembly code size

      trace_method_handle(_masm, "bad Method*::intrinsic_id");

    }

    __ hlt(0);

    __ bind(L);

    BLOCK_COMMENT("} verify_intrinsic_id");

  }

  // First task:  Find out how big the argument list is.

  Address r3_first_arg_addr;

  int ref_kind = signature_polymorphic_intrinsic_ref_kind(iid);

  assert(ref_kind != 0 || iid == vmIntrinsics::_invokeBasic, "must be _invokeBasic or a linkTo intrinsic");

  if (ref_kind == 0 || MethodHandles::ref_kind_has_receiver(ref_kind)) {

    __ ldr(argp, Address(rmethod, Method::const_offset()));

    __ load_sized_value(argp,

                        Address(argp, ConstMethod::size_of_parameters_offset()),

                        sizeof(u2), /*is_signed*/ false);

    // assert(sizeof(u2) == sizeof(Method::_size_of_parameters), "");

    r3_first_arg_addr = __ argument_address(argp, -1);

  } else {

    DEBUG_ONLY(argp = noreg);

  }

  if (!is_signature_polymorphic_static(iid)) {

    __ ldr(mh, r3_first_arg_addr);

    DEBUG_ONLY(argp = noreg);

  }

  // r3_first_arg_addr is live!

  trace_method_handle_interpreter_entry(_masm, iid);

  if (iid == vmIntrinsics::_invokeBasic) {

    generate_method_handle_dispatch(_masm, iid, mh, noreg, not_for_compiler_entry);

  } else {

    // Adjust argument list by popping the trailing MemberName argument.

    Register recv = noreg;

    if (MethodHandles::ref_kind_has_receiver(ref_kind)) {

      // Load the receiver (not the MH; the actual MemberName's receiver) up from the interpreter stack.

      __ ldr(recv = r2, r3_first_arg_addr);

    }

    DEBUG_ONLY(argp = noreg);

    Register rmember = rmethod;  // MemberName ptr; incoming method ptr is dead now

    __ pop(rmember);             // extract last argument

    generate_method_handle_dispatch(_masm, iid, recv, rmember, not_for_compiler_entry);

  }

  return entry_point;

}

void MethodHandles::generate_method_handle_dispatch(MacroAssembler* _masm,

                                                    vmIntrinsics::ID iid,

                                                    Register receiver_reg,

                                                    Register member_reg,

                                                    bool for_compiler_entry) {

  assert(is_signature_polymorphic(iid), "expected invoke iid");

  // temps used in this code are not used in *either* compiled or interpreted calling sequences

  Register temp1 = r10;

  Register temp2 = r11;

  Register temp3 = r14;  // r13 is live by this point: it contains the sender SP

  if (for_compiler_entry) {

    assert(receiver_reg == (iid == vmIntrinsics::_linkToStatic ? noreg : j_rarg0), "only valid assignment");

    assert_different_registers(temp1,        j_rarg0, j_rarg1, j_rarg2, j_rarg3, j_rarg4, j_rarg5, j_rarg6, j_rarg7);

    assert_different_registers(temp2,        j_rarg0, j_rarg1, j_rarg2, j_rarg3, j_rarg4, j_rarg5, j_rarg6, j_rarg7);

    assert_different_registers(temp3,        j_rarg0, j_rarg1, j_rarg2, j_rarg3, j_rarg4, j_rarg5, j_rarg6, j_rarg7);

  }

  assert_different_registers(temp1, temp2, temp3, receiver_reg);

  assert_different_registers(temp1, temp2, temp3, member_reg);

  if (iid == vmIntrinsics::_invokeBasic) {

    // indirect through MH.form.vmentry.vmtarget

    jump_to_lambda_form(_masm, receiver_reg, rmethod, temp1, for_compiler_entry);

  } else {

    // The method is a member invoker used by direct method handles.

    if (VerifyMethodHandles) {

      // make sure the trailing argument really is a MemberName (caller responsibility)

      verify_klass(_masm, member_reg, SystemDictionary::WK_KLASS_ENUM_NAME(java_lang_invoke_MemberName),

                   "MemberName required for invokeVirtual etc.");

    }

    Address member_clazz(    member_reg, NONZERO(java_lang_invoke_MemberName::clazz_offset_in_bytes()));

    Address member_vmindex(  member_reg, NONZERO(java_lang_invoke_MemberName::vmindex_offset_in_bytes()));

    Register temp1_recv_klass = temp1;

    if (iid != vmIntrinsics::_linkToStatic) {

      __ verify_oop(receiver_reg);

      if (iid == vmIntrinsics::_linkToSpecial) {

        // Don't actually load the klass; just null-check the receiver.

        __ null_check(receiver_reg);

      } else {

        // load receiver klass itself

        __ null_check(receiver_reg, oopDesc::klass_offset_in_bytes());

        __ load_klass(temp1_recv_klass, receiver_reg);

        __ verify_klass_ptr(temp1_recv_klass);

      }

      BLOCK_COMMENT("check_receiver {");

      // The receiver for the MemberName must be in receiver_reg.

      // Check the receiver against the MemberName.clazz

      if (VerifyMethodHandles && iid == vmIntrinsics::_linkToSpecial) {

        // Did not load it above...

        __ load_klass(temp1_recv_klass, receiver_reg);

        __ verify_klass_ptr(temp1_recv_klass);

      }

      if (VerifyMethodHandles && iid != vmIntrinsics::_linkToInterface) {

        Label L_ok;

        Register temp2_defc = temp2;

        __ load_heap_oop(temp2_defc, member_clazz);

        load_klass_from_Class(_masm, temp2_defc);

        __ verify_klass_ptr(temp2_defc);

        __ check_klass_subtype(temp1_recv_klass, temp2_defc, temp3, L_ok);

        // If we get here, the type check failed!

        __ hlt(0);

        // __ STOP("receiver class disagrees with MemberName.clazz");

        __ bind(L_ok);

      }

      BLOCK_COMMENT("} check_receiver");

    }

    if (iid == vmIntrinsics::_linkToSpecial ||

        iid == vmIntrinsics::_linkToStatic) {

      DEBUG_ONLY(temp1_recv_klass = noreg);  // these guys didn't load the recv_klass

    }

    // Live registers at this point:

    //  member_reg - MemberName that was the trailing argument

    //  temp1_recv_klass - klass of stacked receiver, if needed

    //  r13 - interpreter linkage (if interpreted)  ??? FIXME

    //  r1 ... r0 - compiler arguments (if compiled)

    Label L_incompatible_class_change_error;

    switch (iid) {

    case vmIntrinsics::_linkToSpecial:

      if (VerifyMethodHandles) {

        verify_ref_kind(_masm, JVM_REF_invokeSpecial, member_reg, temp3);

      }

      break;

    case vmIntrinsics::_linkToStatic:

      if (VerifyMethodHandles) {

        verify_ref_kind(_masm, JVM_REF_invokeStatic, member_reg, temp3);

      }

      break;

    case vmIntrinsics::_linkToVirtual:

    {

      // same as TemplateTable::invokevirtual,

      // minus the CP setup and profiling:

      if (VerifyMethodHandles) {

        verify_ref_kind(_masm, JVM_REF_invokeVirtual, member_reg, temp3);

      }

      // pick out the vtable index from the MemberName, and then we can discard it:

      Register temp2_index = temp2;

      __ ldr(temp2_index, member_vmindex);

      if (VerifyMethodHandles) {

        Label L_index_ok;

        __ cmpw(temp2_index, 0U);

        __ br(Assembler::GE, L_index_ok);

        __ hlt(0);

        __ BIND(L_index_ok);

      }

      // Note:  The verifier invariants allow us to ignore MemberName.clazz and vmtarget

      // at this point.  And VerifyMethodHandles has already checked clazz, if needed.

      // get target Method* & entry point

      __ lookup_virtual_method(temp1_recv_klass, temp2_index, rmethod);

      break;

    }

    case vmIntrinsics::_linkToInterface:

    {

      // same as TemplateTable::invokeinterface

      // (minus the CP setup and profiling, with different argument motion)

      if (VerifyMethodHandles) {

        verify_ref_kind(_masm, JVM_REF_invokeInterface, member_reg, temp3);

      }

      Register temp3_intf = temp3;

      __ load_heap_oop(temp3_intf, member_clazz);

      load_klass_from_Class(_masm, temp3_intf);

      __ verify_klass_ptr(temp3_intf);

      Register rindex = rmethod;

      __ ldr(rindex, member_vmindex);

      if (VerifyMethodHandles) {

        Label L;

        __ cmpw(rindex, 0U);

        __ br(Assembler::GE, L);

        __ hlt(0);

        __ bind(L);

      }

      // given intf, index, and recv klass, dispatch to the implementation method

      __ lookup_interface_method(temp1_recv_klass, temp3_intf,

                                 // note: next two args must be the same:

                                 rindex, rmethod,

                                 temp2,

                                 L_incompatible_class_change_error);

      break;

    }

    default:

      fatal("unexpected intrinsic %d: %s", iid, vmIntrinsics::name_at(iid));

      break;

    }

    // live at this point:  rmethod, r13 (if interpreted)

    // After figuring out which concrete method to call, jump into it.

    // Note that this works in the interpreter with no data motion.

    // But the compiled version will require that r2_recv be shifted out.

    __ verify_method_ptr(rmethod);

    jump_from_method_handle(_masm, rmethod, temp1, for_compiler_entry);

    if (iid == vmIntrinsics::_linkToInterface) {

      __ bind(L_incompatible_class_change_error);

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

    }

  }

}

#ifndef PRODUCT

void trace_method_handle_stub(const char* adaptername,

                              oop mh,

                              intptr_t* saved_regs,

                              intptr_t* entry_sp) {  }

// The stub wraps the arguments in a struct on the stack to avoid

// dealing with the different calling conventions for passing 6

// arguments.

struct MethodHandleStubArguments {

  const char* adaptername;

  oopDesc* mh;

  intptr_t* saved_regs;

  intptr_t* entry_sp;

};

void trace_method_handle_stub_wrapper(MethodHandleStubArguments* args) {  }

void MethodHandles::trace_method_handle(MacroAssembler* _masm, const char* adaptername) {  }

#endif //PRODUCT