/*

 * Copyright 2009, 2010 Red Hat, Inc.

 * 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 "shark/llvmHeaders.hpp"

#include "shark/sharkNativeWrapper.hpp"

#include "shark/sharkType.hpp"

using namespace llvm;

void SharkNativeWrapper::initialize(const char *name) {

  // Create the function

  _function = Function::Create(

    SharkType::entry_point_type(),

    GlobalVariable::InternalLinkage,

    name);

  // Get our arguments

  Function::arg_iterator ai = function()->arg_begin();

  Argument *method = ai++;

  method->setName("method");

  Argument *base_pc = ai++;

  base_pc->setName("base_pc");

  code_buffer()->set_base_pc(base_pc);

  Argument *thread = ai++;

  thread->setName("thread");

  set_thread(thread);

  // Create and push our stack frame

  builder()->SetInsertPoint(CreateBlock());

  _stack = SharkStack::CreateBuildAndPushFrame(this, method);

  NOT_PRODUCT(method = NULL);

  // Create the oopmap.  We use the one oopmap for every call site in

  // the wrapper, which results in the odd mild inefficiency but is a

  // damn sight easier to code.

  OopMap *oopmap = new OopMap(

    SharkStack::oopmap_slot_munge(stack()->oopmap_frame_size()),

    SharkStack::oopmap_slot_munge(arg_size()));

  oopmap->set_oop(SharkStack::slot2reg(stack()->method_slot_offset()));

  // Set up the oop_tmp slot if required:

  //  - For static methods we use it to handlize the class argument

  //    for the call, and to protect the same during slow path locks

  //    (if synchronized).

  //  - For methods returning oops, we use it to protect the return

  //    value across safepoints or slow path unlocking.

  if (is_static() || is_returning_oop()) {

    _oop_tmp_slot = stack()->slot_addr(

      stack()->oop_tmp_slot_offset(),

      SharkType::oop_type(),

      "oop_tmp_slot");

    oopmap->set_oop(SharkStack::slot2reg(stack()->oop_tmp_slot_offset()));

  }

  // Set up the monitor slot, for synchronized methods

  if (is_synchronized()) {

    Unimplemented();

    _lock_slot_offset = 23;

  }

  // Start building the argument list

  std::vector<const Type*> param_types;

  std::vector<Value*> param_values;

  const PointerType *box_type = PointerType::getUnqual(SharkType::oop_type());

  // First argument is the JNIEnv

  param_types.push_back(SharkType::jniEnv_type());

  param_values.push_back(

    builder()->CreateAddressOfStructEntry(

      thread,

      JavaThread::jni_environment_offset(),

      SharkType::jniEnv_type(),

      "jni_environment"));

  // For static methods, the second argument is the class

  if (is_static()) {

    builder()->CreateStore(

      builder()->CreateInlineOop(

        JNIHandles::make_local(

          target()->method_holder()->java_mirror())),

      oop_tmp_slot());

    param_types.push_back(box_type);

    param_values.push_back(oop_tmp_slot());

    _receiver_slot_offset = stack()->oop_tmp_slot_offset();

  }

  else if (is_returning_oop()) {

    // The oop_tmp slot is registered in the oopmap,

    // so we need to clear it.  This is one of the

    // mild inefficiencies I mentioned earlier.

    builder()->CreateStore(LLVMValue::null(), oop_tmp_slot());

  }

  // Parse the arguments

  for (int i = 0; i < arg_size(); i++) {

    int slot_offset = stack()->locals_slots_offset() + arg_size() - 1 - i;

    int adjusted_offset = slot_offset;

    BasicBlock *null, *not_null, *merge;

    Value *box;

    PHINode *phi;

    switch (arg_type(i)) {

    case T_VOID:

      break;

    case T_OBJECT:

    case T_ARRAY:

      null     = CreateBlock("null");

      not_null = CreateBlock("not_null");

      merge    = CreateBlock("merge");

      box = stack()->slot_addr(slot_offset, SharkType::oop_type());

      builder()->CreateCondBr(

        builder()->CreateICmp(

          ICmpInst::ICMP_EQ,

          builder()->CreateLoad(box),

          LLVMValue::null()),

        null, not_null);

      builder()->SetInsertPoint(null);

      builder()->CreateBr(merge);

      builder()->SetInsertPoint(not_null);

      builder()->CreateBr(merge);

      builder()->SetInsertPoint(merge);

      phi = builder()->CreatePHI(box_type, "boxed_object");

      phi->addIncoming(ConstantPointerNull::get(box_type), null);

      phi->addIncoming(box, not_null);

      box = phi;

      param_types.push_back(box_type);

      param_values.push_back(box);

      oopmap->set_oop(SharkStack::slot2reg(slot_offset));

      if (i == 0 && !is_static())

        _receiver_slot_offset = slot_offset;

      break;

    case T_LONG:

    case T_DOUBLE:

      adjusted_offset--;

      // fall through

    default:

      const Type *param_type = SharkType::to_stackType(arg_type(i));

      param_types.push_back(param_type);

      param_values.push_back(

        builder()->CreateLoad(stack()->slot_addr(adjusted_offset, param_type)));

    }

  }

  // The oopmap is now complete, and everything is written

  // into the frame except the PC.

  int pc_offset = code_buffer()->create_unique_offset();

  _oop_maps = new OopMapSet();

  oop_maps()->add_gc_map(pc_offset, oopmap);

  builder()->CreateStore(

    builder()->code_buffer_address(pc_offset),

    stack()->slot_addr(stack()->pc_slot_offset()));

  // Set up the Java frame anchor

  stack()->CreateSetLastJavaFrame();

  // Lock if necessary

  if (is_synchronized())

    Unimplemented();

  // Change the thread state to _thread_in_native

  CreateSetThreadState(_thread_in_native);

  // Make the call

  BasicType result_type = target()->result_type();

  const Type* return_type;

  if (result_type == T_VOID)

    return_type = SharkType::void_type();

  else if (is_returning_oop())

    return_type = box_type;

  else

    return_type = SharkType::to_arrayType(result_type);

  Value* native_function = builder()->CreateIntToPtr(

     LLVMValue::intptr_constant((intptr_t) target()->native_function()),

     PointerType::getUnqual(

       FunctionType::get(return_type, param_types, false)));

  Value *result = builder()->CreateCall(

    native_function, param_values.begin(), param_values.end());

  // Start the transition back to _thread_in_Java

  CreateSetThreadState(_thread_in_native_trans);

  // Make sure new state is visible in the GC thread

  if (os::is_MP()) {

    if (UseMembar)

      builder()->CreateMemoryBarrier(SharkBuilder::BARRIER_STORELOAD);

    else

      CreateWriteMemorySerializePage();

  }

  // Handle safepoint operations, pending suspend requests,

  // and pending asynchronous exceptions.

  BasicBlock *check_thread = CreateBlock("check_thread");

  BasicBlock *do_safepoint = CreateBlock("do_safepoint");

  BasicBlock *safepointed  = CreateBlock("safepointed");

  Value *global_state = builder()->CreateLoad(

    builder()->CreateIntToPtr(

      LLVMValue::intptr_constant(

        (intptr_t) SafepointSynchronize::address_of_state()),

      PointerType::getUnqual(SharkType::jint_type())),

    "global_state");

  builder()->CreateCondBr(

    builder()->CreateICmpNE(

      global_state,

      LLVMValue::jint_constant(SafepointSynchronize::_not_synchronized)),

    do_safepoint, check_thread);

  builder()->SetInsertPoint(check_thread);

  Value *thread_state = builder()->CreateValueOfStructEntry(

    thread,

    JavaThread::suspend_flags_offset(),

    SharkType::jint_type(),

    "thread_state");

  builder()->CreateCondBr(

    builder()->CreateICmpNE(

      thread_state,

      LLVMValue::jint_constant(0)),

    do_safepoint, safepointed);

  builder()->SetInsertPoint(do_safepoint);

  builder()->CreateCall(

    builder()->check_special_condition_for_native_trans(), thread);

  builder()->CreateBr(safepointed);

  // Finally we can change the thread state to _thread_in_Java

  builder()->SetInsertPoint(safepointed);

  CreateSetThreadState(_thread_in_Java);

  // Clear the frame anchor

  stack()->CreateResetLastJavaFrame();

  // If there is a pending exception then we can just unwind and

  // return.  It seems totally wrong that unlocking is skipped here

  // but apparently the template interpreter does this so we do too.

  BasicBlock *exception    = CreateBlock("exception");

  BasicBlock *no_exception = CreateBlock("no_exception");

  builder()->CreateCondBr(

    builder()->CreateICmpEQ(

      CreateLoadPendingException(),

      LLVMValue::null()),

    no_exception, exception);

  builder()->SetInsertPoint(exception);

  CreateResetHandleBlock();

  stack()->CreatePopFrame(0);

  builder()->CreateRet(LLVMValue::jint_constant(0));

  builder()->SetInsertPoint(no_exception);

  // If the result was an oop then unbox it before

  // releasing the handle it might be protected by

  if (is_returning_oop()) {

    BasicBlock *null     = builder()->GetInsertBlock();

    BasicBlock *not_null = CreateBlock("not_null");

    BasicBlock *merge    = CreateBlock("merge");

    builder()->CreateCondBr(

      builder()->CreateICmpNE(result, ConstantPointerNull::get(box_type)),

      not_null, merge);

    builder()->SetInsertPoint(not_null);

    Value *unboxed_result = builder()->CreateLoad(result);

    builder()->CreateBr(merge);

    builder()->SetInsertPoint(merge);

    PHINode *phi = builder()->CreatePHI(SharkType::oop_type(), "result");

    phi->addIncoming(LLVMValue::null(), null);

    phi->addIncoming(unboxed_result, not_null);

    result = phi;

  }

  // Reset handle block

  CreateResetHandleBlock();

  // Unlock if necessary.

  if (is_synchronized())

    Unimplemented();

  // Unwind and return

  Value *result_addr = stack()->CreatePopFrame(type2size[result_type]);

  if (result_type != T_VOID) {

    bool needs_cast = false;

    bool is_signed = false;

    switch (result_type) {

    case T_BOOLEAN:

      result = builder()->CreateICmpNE(result, LLVMValue::jbyte_constant(0));

      needs_cast = true;

      break;

    case T_CHAR:

      needs_cast = true;

      break;

    case T_BYTE:

    case T_SHORT:

      needs_cast = true;

      is_signed = true;

      break;

    }

    if (needs_cast) {

      result = builder()->CreateIntCast(

        result, SharkType::to_stackType(result_type), is_signed);

    }

    builder()->CreateStore(

      result,

      builder()->CreateIntToPtr(

        result_addr,

        PointerType::getUnqual(SharkType::to_stackType(result_type))));

  }

  builder()->CreateRet(LLVMValue::jint_constant(0));

}