/*

 * Copyright (c) 1997, 2012, 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 "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 */

#define STOP(error) stop(error)

#else

#define BLOCK_COMMENT(str) __ block_comment(str)

#define STOP(error) block_comment(error); __ stop(error)

#endif

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

// Workaround for C++ overloading nastiness on '0' for RegisterOrConstant.

static RegisterOrConstant constant(int value) {

  return RegisterOrConstant(value);

}

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");

  __ movptr(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, err_msg("%s should be nonzero", xname));

  return x;

}

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

#else //ASSERT

#define NONZERO(x) (x)

#endif //ASSERT

#ifdef ASSERT

void MethodHandles::verify_klass(MacroAssembler* _masm,

                                 Register obj, SystemDictionary::WKID klass_id,

                                 const char* error_message) {

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

  KlassHandle klass = SystemDictionary::well_known_klass(klass_id);

  Register temp = rdi;

  Register temp2 = noreg;

  LP64_ONLY(temp2 = rscratch1);  // used by MacroAssembler::cmpptr

  Label L_ok, L_bad;

  BLOCK_COMMENT("verify_klass {");

  __ verify_oop(obj);

  __ testptr(obj, obj);

  __ jcc(Assembler::zero, L_bad);

  __ push(temp); if (temp2 != noreg)  __ push(temp2);

#define UNPUSH { if (temp2 != noreg)  __ pop(temp2);  __ pop(temp); }

  __ load_klass(temp, obj);

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

  __ jcc(Assembler::equal, L_ok);

  intptr_t super_check_offset = klass->super_check_offset();

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

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

  __ jcc(Assembler::equal, L_ok);

  UNPUSH;

  __ bind(L_bad);

  __ STOP(error_message);

  __ BIND(L_ok);

  UNPUSH;

  BLOCK_COMMENT("} verify_klass");

}

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

  Label L;

  BLOCK_COMMENT("verify_ref_kind {");

  __ movl(temp, Address(member_reg, NONZERO(java_lang_invoke_MemberName::flags_offset_in_bytes())));

  __ shrl(temp, java_lang_invoke_MemberName::MN_REFERENCE_KIND_SHIFT);

  __ andl(temp, java_lang_invoke_MemberName::MN_REFERENCE_KIND_MASK);

  __ cmpl(temp, ref_kind);

  __ jcc(Assembler::equal, L);

  { char* buf = NEW_C_HEAP_ARRAY(char, 100, mtInternal);

    jio_snprintf(buf, 100, "verify_ref_kind expected %x", ref_kind);

    if (ref_kind == JVM_REF_invokeVirtual ||

        ref_kind == JVM_REF_invokeSpecial)

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

      trace_method_handle(_masm, buf);

    __ STOP(buf);

  }

  BLOCK_COMMENT("} verify_ref_kind");

  __ bind(L);

}

#endif //ASSERT

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

                                            bool for_compiler_entry) {

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

  __ 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.

#ifdef _LP64

    Register rthread = r15_thread;

#else

    Register rthread = temp;

    __ get_thread(rthread);

#endif

    // interp_only is an int, on little endian it is sufficient to test the byte only

    // Is a cmpl faster?

    __ cmpb(Address(rthread, JavaThread::interp_only_mode_offset()), 0);

    __ jccb(Assembler::zero, run_compiled_code);

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

    __ BIND(run_compiled_code);

  }

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

                                                     Method::from_interpreted_offset();

  __ jmp(Address(method, entry_offset));

}

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 == rbx, "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);

  // the following assumes that a Method* is normally compressed in the vmtarget field:

  __ movptr(method_temp, Address(method_temp, NONZERO(java_lang_invoke_MemberName::vmtarget_offset_in_bytes())));

  if (VerifyMethodHandles && !for_compiler_entry) {

    // make sure recv is already on stack

    __ load_sized_value(temp2,

                        Address(method_temp, Method::size_of_parameters_offset()),

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

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

    Label L;

    __ cmpptr(recv, __ argument_address(temp2, -1));

    __ jcc(Assembler::equal, L);

    __ movptr(rax, __ argument_address(temp2, -1));

    __ STOP("receiver not on stack");

    __ 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();           // empty stubs make SG sick

    return NULL;

  }

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

  // rbx: Method*

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

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

  // rax, rdi: garbage temps, blown away

  Register rdx_argp   = rdx;   // argument list ptr, live on error paths

  Register rax_temp   = rax;

  Register rcx_mh     = rcx;   // MH receiver; dies quickly and is recycled

  Register rbx_method = rbx;   // eventual target of this invocation

  address code_start = __ pc();

  // here's where control starts out:

  __ align(CodeEntryAlignment);

  address entry_point = __ pc();

  if (VerifyMethodHandles) {

    Label L;

    BLOCK_COMMENT("verify_intrinsic_id {");

    __ cmpb(Address(rbx_method, Method::intrinsic_id_offset_in_bytes()), (int) iid);

    __ jcc(Assembler::equal, 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");

    }

    __ STOP("bad Method*::intrinsic_id");

    __ bind(L);

    BLOCK_COMMENT("} verify_intrinsic_id");

  }

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

  Address rdx_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)) {

    __ load_sized_value(rdx_argp,

                        Address(rbx_method, Method::size_of_parameters_offset()),

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

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

    rdx_first_arg_addr = __ argument_address(rdx_argp, -1);

  } else {

    DEBUG_ONLY(rdx_argp = noreg);

  }

  if (!is_signature_polymorphic_static(iid)) {

    __ movptr(rcx_mh, rdx_first_arg_addr);

    DEBUG_ONLY(rdx_argp = noreg);

  }

  // rdx_first_arg_addr is live!

  if (TraceMethodHandles) {

    const char* name = vmIntrinsics::name_at(iid);

    if (*name == '_')  name += 1;

    const size_t len = strlen(name) + 50;

    char* qname = NEW_C_HEAP_ARRAY(char, len, mtInternal);

    const char* suffix = "";

    if (vmIntrinsics::method_for(iid) == NULL ||

        !vmIntrinsics::method_for(iid)->access_flags().is_public()) {

      if (is_signature_polymorphic_static(iid))

        suffix = "/static";

      else

        suffix = "/private";

    }

    jio_snprintf(qname, len, "MethodHandle::interpreter_entry::%s%s", name, suffix);

    // note: stub look for mh in rcx

    trace_method_handle(_masm, qname);

  }

  if (iid == vmIntrinsics::_invokeBasic) {

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

  } else {

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

    Register rcx_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.

      __ movptr(rcx_recv = rcx, rdx_first_arg_addr);

    }

    DEBUG_ONLY(rdx_argp = noreg);

    Register rbx_member = rbx_method;  // MemberName ptr; incoming method ptr is dead now

    __ pop(rax_temp);           // return address

    __ pop(rbx_member);         // extract last argument

    __ push(rax_temp);          // re-push return address

    generate_method_handle_dispatch(_masm, iid, rcx_recv, rbx_member, not_for_compiler_entry);

  }

  if (PrintMethodHandleStubs) {

    address code_end = __ pc();

    tty->print_cr("--------");

    tty->print_cr("method handle interpreter entry for %s", vmIntrinsics::name_at(iid));

    Disassembler::decode(code_start, code_end);

    tty->cr();

  }

  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");

  Register rbx_method = rbx;   // eventual target of this invocation

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

#ifdef _LP64

  Register temp1 = rscratch1;

  Register temp2 = rscratch2;

  Register temp3 = rax;

  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);

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

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

  }

#else

  Register temp1 = (for_compiler_entry ? rsi : rdx);

  Register temp2 = rdi;

  Register temp3 = rax;

  if (for_compiler_entry) {

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

    assert_different_registers(temp1,        rcx, rdx);

    assert_different_registers(temp2,        rcx, rdx);

    assert_different_registers(temp3,        rcx, rdx);

  }

#endif

  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, rbx_method, 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()));

    Address member_vmtarget( member_reg, NONZERO(java_lang_invoke_MemberName::vmtarget_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!

        __ 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

    //  rsi/r13 - interpreter linkage (if interpreted)

    //  rcx, rdx, rsi, rdi, r8, r8 - compiler arguments (if compiled)

    switch (iid) {

    case vmIntrinsics::_linkToSpecial:

      if (VerifyMethodHandles) {

        verify_ref_kind(_masm, JVM_REF_invokeSpecial, member_reg, temp3);

      }

      __ movptr(rbx_method, member_vmtarget);

      break;

    case vmIntrinsics::_linkToStatic:

      if (VerifyMethodHandles) {

        verify_ref_kind(_masm, JVM_REF_invokeStatic, member_reg, temp3);

      }

      __ movptr(rbx_method, member_vmtarget);

      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;

      __ movptr(temp2_index, member_vmindex);

      if (VerifyMethodHandles) {

        Label L_index_ok;

        __ cmpl(temp2_index, 0);

        __ jcc(Assembler::greaterEqual, L_index_ok);

        __ STOP("no virtual index");

        __ 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, rbx_method);

      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 rbx_index = rbx_method;

      __ movptr(rbx_index, member_vmindex);

      if (VerifyMethodHandles) {

        Label L;

        __ cmpl(rbx_index, 0);

        __ jcc(Assembler::greaterEqual, L);

        __ STOP("invalid vtable index for MH.invokeInterface");

        __ 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:

                                 rbx_index, rbx_method,

                                 temp2,

      break;

    }

    default:

      break;

    }