/**
 ******************************************************************************
 * Xenia : Xbox 360 Emulator Research Project                                 *
 ******************************************************************************
 * Copyright 2013 Ben Vanik. All rights reserved.                             *
 * Released under the BSD license - see LICENSE in the root for more details. *
 ******************************************************************************
 */

#include <xenia/cpu/exec_module.h>

#include <llvm/Linker.h>
#include <llvm/PassManager.h>
#include <llvm/Analysis/Verifier.h>
#include <llvm/Bitcode/ReaderWriter.h>
#include <llvm/ExecutionEngine/GenericValue.h>
#include <llvm/ExecutionEngine/ExecutionEngine.h>
#include <llvm/IR/DataLayout.h>
#include <llvm/IR/DerivedTypes.h>
#include <llvm/IR/LLVMContext.h>
#include <llvm/IR/Module.h>
#include <llvm/Support/Host.h>
#include <llvm/Support/MemoryBuffer.h>
#include <llvm/Support/raw_ostream.h>
#include <llvm/Support/system_error.h>
#include <llvm/Support/Threading.h>
#include <llvm/Transforms/IPO.h>
#include <llvm/Transforms/IPO/PassManagerBuilder.h>

#include <xenia/cpu/codegen.h>
#include <xenia/cpu/sdb.h>

#include "cpu/xethunk/xethunk.h"


using namespace llvm;
using namespace xe;
using namespace xe::cpu;
using namespace xe::cpu::codegen;
using namespace xe::kernel;


ExecModule::ExecModule(
    xe_memory_ref memory, shared_ptr<ExportResolver> export_resolver,
    UserModule* user_module, shared_ptr<llvm::ExecutionEngine>& engine) {
  memory_ = xe_memory_retain(memory);
  export_resolver_ = export_resolver;
  module_ = user_module;
  engine_ = engine;
  sdb_ = shared_ptr<sdb::SymbolDatabase>(
      new sdb::SymbolDatabase(memory_, module_));

  context_ = shared_ptr<LLVMContext>(new LLVMContext());
}

ExecModule::~ExecModule() {
  if (gen_module_) {
    Uninit();
    engine_->removeModule(gen_module_.get());
  }

  xe_memory_release(memory_);
}

int ExecModule::Prepare() {
  int result_code = 1;
  std::string error_message;

  OwningPtr<MemoryBuffer> shared_module_buffer;
  auto_ptr<Module> shared_module;
  auto_ptr<raw_ostream> outs;

  PassManager pm;
  PassManagerBuilder pmb;

  // TODO(benvanik): embed the bc file into the emulator.
  const char *thunk_path = "src/cpu/xethunk/xethunk.bc";

  // Calculate a cache path based on the module, the CPU version, and other
  // bits.
  // TODO(benvanik): cache path calculation.
  const char *cache_path = "build/generated.bc";

  // Check the cache to see if the bitcode exists.
  // If it does, load that module directly. In the future we could also cache
  // on linked binaries but that requires more safety around versioning.
  // TODO(benvanik): check cache for module bitcode and load.
  // if (path_exists(cache_key)) {
  //   exec_module = load_bitcode(cache_key);
  //   sdb = load_symbol_table(cache_key);
  // }

  // If not found in cache, generate a new module.
  if (!gen_module_.get()) {
    // Load shared bitcode files.
    // These contain globals and common thunk code that are used by the
    // generated code.
    XEEXPECTZERO(MemoryBuffer::getFile(thunk_path, shared_module_buffer));
    shared_module = auto_ptr<Module>(ParseBitcodeFile(
        &*shared_module_buffer, *context_, &error_message));
    XEEXPECTNOTNULL(shared_module.get());

    // Analyze the module and add its symbols to the symbol database.
    XEEXPECTZERO(sdb_->Analyze());

    // Initialize the module.
    gen_module_ = shared_ptr<Module>(
        new Module(module_->name(), *context_.get()));
    // TODO(benavnik): addModuleFlag?

    // Link shared module into generated module.
    // This gives us a single module that we can optimize and prevents the need
    // for foreward declarations.
    Linker::LinkModules(gen_module_.get(), shared_module.get(), 0,
                        &error_message);

    // Build the module from the source code.
    codegen_ = auto_ptr<CodegenContext>(new CodegenContext(
        memory_, export_resolver_.get(), module_, sdb_.get(),
        context_.get(), gen_module_.get()));
    XEEXPECTZERO(codegen_->GenerateModule());

    // Write to cache.
    outs = auto_ptr<raw_ostream>(new raw_fd_ostream(
        cache_path, error_message, raw_fd_ostream::F_Binary));
    XEEXPECTTRUE(error_message.empty());
    WriteBitcodeToFile(gen_module_.get(), *outs);
  }

  // Link optimizations.
  XEEXPECTZERO(gen_module_->MaterializeAllPermanently(&error_message));

  // Reset target triple (ignore what's in xethunk).
  gen_module_->setTargetTriple(llvm::sys::getDefaultTargetTriple());

  // Run full module optimizations.
  pm.add(new DataLayout(gen_module_.get()));
  pm.add(createVerifierPass());
  pmb.OptLevel      = 3;
  pmb.SizeLevel     = 0;
  pmb.Inliner       = createFunctionInliningPass();
  pmb.Vectorize     = true;
  pmb.LoopVectorize = true;
  pmb.populateModulePassManager(pm);
  pmb.populateLTOPassManager(pm, false, true);
  pm.add(createVerifierPass());
  pm.run(*gen_module_);

  // TODO(benvanik): experiment with LLD to see if we can write out a dll.

  // Initialize the module.
  XEEXPECTZERO(Init());

  // Force JIT of all functions.
  for (Module::iterator I = gen_module_->begin(), E = gen_module_->end();
       I != E; I++) {
    Function* fn = &*I;
    if (!fn->isDeclaration()) {
      engine_->getPointerToFunction(fn);
    }
  }

  result_code = 0;
XECLEANUP:
  return result_code;
}

int ExecModule::Init() {
  // Run static initializers. I'm not sure we'll have any, but who knows.
  engine_->runStaticConstructorsDestructors(gen_module_.get(), false);

  // Prepare init options.
  xe_module_init_options_t init_options;
  xe_zero_struct(&init_options, sizeof(init_options));
  init_options.memory_base = xe_memory_addr(memory_, 0);

  // Grab the init function and call it.
  Function* xe_module_init = gen_module_->getFunction("xe_module_init");
  std::vector<GenericValue> args;
  args.push_back(GenericValue(&init_options));
  GenericValue ret = engine_->runFunction(xe_module_init, args);

  return ret.IntVal.getSExtValue();
}

int ExecModule::Uninit() {
  // Grab function and call it.
  Function* xe_module_uninit = gen_module_->getFunction("xe_module_uninit");
  std::vector<GenericValue> args;
  engine_->runFunction(xe_module_uninit, args);

  // Run static destructors.
  engine_->runStaticConstructorsDestructors(gen_module_.get(), true);

  return 0;
}

void ExecModule::Dump() {
  sdb_->Dump();
  gen_module_->dump();
}