#include "ExecutionEngine.h"

#include <chrono>

#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wunused-parameter"

#include <llvm/IR/LLVMContext.h>
#include <llvm/IR/Module.h>
#include <llvm/ADT/Triple.h>
#include <llvm/ExecutionEngine/ExecutionEngine.h>
#include <llvm/ExecutionEngine/SectionMemoryManager.h>
#include <llvm/ExecutionEngine/GenericValue.h>
#include <llvm/ExecutionEngine/MCJIT.h>
#include <llvm/Support/TargetSelect.h>
#include <llvm/Support/Signals.h>
#include <llvm/Support/PrettyStackTrace.h>
#include <llvm/Support/Host.h>

#pragma GCC diagnostic pop

#include "Runtime.h"
#include "Memory.h"
#include "Stack.h"
#include "Type.h"
#include "Compiler.h"
#include "Cache.h"

namespace dev
{
namespace eth
{
namespace jit
{

ReturnCode ExecutionEngine::run(bytes const& _code, RuntimeData* _data, Env* _env)
{
	std::string key{reinterpret_cast<char const*>(_code.data()), _code.size()};
	/*if (auto cachedExec = Cache::findExec(key))
	{
		return run(*cachedExec, _data, _env);
	}*/

	auto module = Compiler({}).compile(_code);
	//module->dump();
	return run(std::move(module), _data, _env, _code);
}

ReturnCode ExecutionEngine::run(std::unique_ptr<llvm::Module> _module, RuntimeData* _data, Env* _env, bytes const& _code)
{
	llvm::sys::PrintStackTraceOnErrorSignal();
	static const auto program = "EVM JIT";
	llvm::PrettyStackTraceProgram X(1, &program);

	llvm::InitializeNativeTarget();
	llvm::InitializeNativeTargetAsmPrinter();

	llvm::EngineBuilder builder(_module.get());
	builder.setEngineKind(llvm::EngineKind::JIT);
	builder.setUseMCJIT(true);
	std::unique_ptr<llvm::SectionMemoryManager> memoryManager(new llvm::SectionMemoryManager);
	builder.setMCJITMemoryManager(memoryManager.get());
	builder.setOptLevel(llvm::CodeGenOpt::None);

	auto triple = llvm::Triple(llvm::sys::getProcessTriple());
	if (triple.getOS() == llvm::Triple::OSType::Win32)
		triple.setObjectFormat(llvm::Triple::ObjectFormatType::ELF);  // MCJIT does not support COFF format
	_module->setTargetTriple(triple.str());

	ExecBundle exec;
	exec.mainFuncName = _module->getModuleIdentifier();
	exec.engine.reset(builder.create());
	if (!exec.engine)
		return ReturnCode::LLVMConfigError;
	_module.release();        // Successfully created llvm::ExecutionEngine takes ownership of the module
	memoryManager.release();  // and memory manager

	exec.engine->setObjectCache(Cache::getObjectCache());

	// TODO: Finalization not needed when llvm::ExecutionEngine::getFunctionAddress used
	//auto finalizationStartTime = std::chrono::high_resolution_clock::now();
	//exec.engine->finalizeObject();
	//auto finalizationEndTime = std::chrono::high_resolution_clock::now();
	//clog(JIT) << " + " << std::chrono::duration_cast<std::chrono::milliseconds>(finalizationEndTime - finalizationStartTime).count();

	auto executionStartTime = std::chrono::high_resolution_clock::now();

	std::string key{reinterpret_cast<char const*>(_code.data()), _code.size()};
	//auto& cachedExec = Cache::registerExec(key, std::move(exec));
	auto returnCode = run(exec, _data, _env);

	auto executionEndTime = std::chrono::high_resolution_clock::now();
	clog(JIT) << " + " << std::chrono::duration_cast<std::chrono::milliseconds>(executionEndTime - executionStartTime).count() << " ms ";
	//clog(JIT) << "Max stack size: " << Stack::maxStackSize;

	clog(JIT) << "\n";

	return returnCode;
}

namespace
{
ReturnCode runEntryFunc(ExecBundle const& _exec, Runtime* _runtime)
{
	// That function uses long jumps to handle "execeptions".
	// Do not create any non-POD objects here

	// TODO:
	// Getting pointer to function seems to be cachable,
	// but it looks like getPointerToFunction() method does something special
	// to allow function to be executed.
	// That might be related to memory manager. Can we share one?
	typedef ReturnCode(*EntryFuncPtr)(Runtime*);
	auto entryFuncPtr = (EntryFuncPtr)_exec.engine->getFunctionAddress(_exec.mainFuncName);

	ReturnCode returnCode{};
	auto sj = setjmp(_runtime->getJmpBuf());
	if (sj == 0)
		returnCode = entryFuncPtr(_runtime);
	else
		returnCode = static_cast<ReturnCode>(sj);

	return returnCode;
}
}

ReturnCode ExecutionEngine::run(ExecBundle const& _exec, RuntimeData* _data, Env* _env)
{
	Runtime runtime(_data, _env);
	auto returnCode = runEntryFunc(_exec, &runtime);
	if (returnCode == ReturnCode::Return)
		this->returnData = runtime.getReturnData();
	return returnCode;
}

}
}
}