You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
188 lines
9.0 KiB
188 lines
9.0 KiB
#include <vm_lifters.hpp>
|
|
#include <vmp_rtn.hpp>
|
|
|
|
namespace vm
|
|
{
|
|
vmp_rtn_t::vmp_rtn_t( llvm::LLVMContext *llvm_ctx, llvm::Module *llvm_module, vm::ctx_t *vm_ctx,
|
|
std::uintptr_t rtn_begin, std::vector< vm::instrs::code_block_t > vmp2_code_blocks )
|
|
: llvm_ctx( llvm_ctx ), llvm_module( llvm_module ), vm_ctx( vm_ctx ), rtn_begin( rtn_begin ),
|
|
vmp2_code_blocks( vmp2_code_blocks )
|
|
{
|
|
// do not change the ordering of these function calls...
|
|
create_routine();
|
|
ir_builder = std::make_shared< llvm::IRBuilder<> >( *llvm_ctx );
|
|
ir_builder->SetInsertPoint( llvm_code_blocks[ 0 ].second );
|
|
flags = ir_builder->CreateAlloca( ir_builder->getInt64Ty(), nullptr, "flags" );
|
|
stack = ir_builder->CreateAlloca( llvm::PointerType::get( ir_builder->getInt8Ty(), 0ull ), nullptr, "sp" );
|
|
|
|
ir_builder->CreateStore( llvm_fptr->getArg( 0 ), stack );
|
|
create_virtual_registers();
|
|
}
|
|
|
|
void vmp_rtn_t::create_virtual_registers( void )
|
|
{
|
|
for ( auto idx = 0u; idx < 24; ++idx )
|
|
// allocate virtual register space...
|
|
virtual_registers.push_back(
|
|
ir_builder->CreateAlloca( llvm::IntegerType::get( *llvm_ctx, 64 ), nullptr,
|
|
( std::string( "vreg" ) + std::to_string( idx ) ).c_str() ) );
|
|
}
|
|
|
|
void vmp_rtn_t::create_routine( void )
|
|
{
|
|
// function has no arguments and returns void... maybe change this in the future as i learn
|
|
// more and more LLVM...
|
|
auto func_ty = llvm::FunctionType::get( llvm::PointerType::getInt8PtrTy( *llvm_ctx ),
|
|
{ llvm::PointerType::getInt8PtrTy( *llvm_ctx ) }, false );
|
|
|
|
// convert the rtn_begin address to a hex string and prepend "rtn_" to it...
|
|
std::stringstream rtn_name;
|
|
rtn_name << "rtn_" << std::hex << rtn_begin;
|
|
llvm_fptr = llvm::Function::Create( func_ty, llvm::GlobalValue::LinkageTypes::ExternalLinkage,
|
|
rtn_name.str().c_str(), *llvm_module );
|
|
|
|
for ( const auto &vmp2_code_block : vmp2_code_blocks )
|
|
{
|
|
// create basic block name... block_xxxxxxxx format...
|
|
std::stringstream blk_name;
|
|
blk_name << "blk_" << std::hex << vmp2_code_block.vip_begin;
|
|
llvm_code_blocks.push_back( { vmp2_code_block.vip_begin,
|
|
llvm::BasicBlock::Create( *llvm_ctx, blk_name.str().c_str(), llvm_fptr ) } );
|
|
}
|
|
}
|
|
|
|
void vmp_rtn_t::push( std::uint8_t num_bytes, llvm::Value *val )
|
|
{
|
|
// sub rsp, num_bytes
|
|
auto rsp_addr = ir_builder->CreateLoad( stack );
|
|
auto rsp_i64 = ir_builder->CreatePtrToInt( rsp_addr, ir_builder->getInt64Ty() );
|
|
auto sub_rsp_val = ir_builder->CreateSub( rsp_i64, ir_builder->getInt64( num_bytes ) );
|
|
ir_builder->CreateStore(
|
|
ir_builder->CreateIntToPtr( sub_rsp_val, llvm::PointerType::get( ir_builder->getInt8Ty(), 0ull ) ), stack );
|
|
|
|
// mov [rsp], val
|
|
rsp_addr = ir_builder->CreateLoad( stack );
|
|
auto rsp_cast_ptr = ir_builder->CreatePointerCast(
|
|
rsp_addr, llvm::PointerType::get( llvm::IntegerType::get( *llvm_ctx, num_bytes * 8 ), false ) );
|
|
ir_builder->CreateStore( val, rsp_cast_ptr );
|
|
}
|
|
|
|
llvm::Value *vmp_rtn_t::pop( std::uint8_t num_bytes )
|
|
{
|
|
// mov rax, [rsp]
|
|
auto rsp_addr = ir_builder->CreateLoad( stack );
|
|
auto rsp_cast_ptr = ir_builder->CreatePointerCast(
|
|
rsp_addr, llvm::PointerType::get( llvm::IntegerType::get( *llvm_ctx, num_bytes * 8 ), false ) );
|
|
auto pop_val = ir_builder->CreateLoad( rsp_cast_ptr );
|
|
|
|
// add rsp, num_bytes
|
|
auto rsp_i64 = ir_builder->CreatePtrToInt( rsp_addr, ir_builder->getInt64Ty() );
|
|
auto sub_rsp_val = ir_builder->CreateAdd( rsp_i64, ir_builder->getInt64( num_bytes ) );
|
|
auto sub_rsp_val_ptr =
|
|
ir_builder->CreateIntToPtr( sub_rsp_val, llvm::PointerType::get( ir_builder->getInt8Ty(), 0ull ) );
|
|
|
|
ir_builder->CreateStore( sub_rsp_val_ptr, stack );
|
|
return pop_val;
|
|
}
|
|
|
|
llvm::Value *vmp_rtn_t::load_value( std::uint8_t byte_size, llvm::GlobalValue *var )
|
|
{
|
|
if ( byte_size * 8 != var->getType()->getPrimitiveSizeInBits() )
|
|
{
|
|
auto cast_ptr = ir_builder->CreatePointerCast(
|
|
var, llvm::PointerType::get( llvm::IntegerType::get( *llvm_ctx, byte_size * 8 ), 0 ) );
|
|
|
|
return ir_builder->CreateLoad( llvm::IntegerType::get( *llvm_ctx, byte_size * 8 ), cast_ptr );
|
|
}
|
|
return ir_builder->CreateLoad( llvm::IntegerType::get( *llvm_ctx, byte_size * 8 ), var );
|
|
}
|
|
|
|
llvm::Value *vmp_rtn_t::load_value( std::uint8_t byte_size, llvm::AllocaInst *var )
|
|
{
|
|
if ( byte_size * 8 != var->getType()->getPrimitiveSizeInBits() )
|
|
{
|
|
auto cast_ptr = ir_builder->CreatePointerCast(
|
|
var, llvm::PointerType::get( llvm::IntegerType::get( *llvm_ctx, byte_size * 8 ), 0 ) );
|
|
|
|
return ir_builder->CreateLoad( llvm::IntegerType::get( *llvm_ctx, byte_size * 8 ), cast_ptr );
|
|
}
|
|
return ir_builder->CreateLoad( llvm::IntegerType::get( *llvm_ctx, byte_size * 8 ), var );
|
|
}
|
|
|
|
llvm::Function *vmp_rtn_t::lift( void )
|
|
{
|
|
auto &code_blocks = llvm_fptr->getBasicBlockList();
|
|
auto lifters = vm::lifters_t::get_instance();
|
|
|
|
for ( auto idx = 0u; idx < code_blocks.size(); ++idx )
|
|
{
|
|
ir_builder->SetInsertPoint( llvm_code_blocks[ idx ].second );
|
|
|
|
for ( auto &vinstr : vmp2_code_blocks[ idx ].vinstrs )
|
|
{
|
|
if ( !lifters->lift( this, vmp2_code_blocks[ idx ], vinstr, ir_builder.get() ) )
|
|
{
|
|
std::printf(
|
|
"> failed to devirtualize virtual instruction with opcode = %d, handler table rva = 0x%x\n",
|
|
vinstr.opcode, vinstr.trace_data.regs.r12 - vinstr.trace_data.regs.r13 );
|
|
|
|
return nullptr;
|
|
}
|
|
}
|
|
}
|
|
|
|
// TODO: update this list of optimizations to add more...
|
|
llvm::legacy::FunctionPassManager fpm( llvm_module );
|
|
fpm.add( llvm::createInstructionCombiningPass() );
|
|
fpm.add( llvm::createReassociatePass() );
|
|
fpm.add( llvm::createGVNPass() );
|
|
fpm.add( llvm::createCFGSimplificationPass() );
|
|
fpm.doInitialization();
|
|
fpm.run( *llvm_fptr );
|
|
return llvm_fptr;
|
|
}
|
|
|
|
llvm::Value *vmp_rtn_t::compute_sf( std::uint8_t byte_size, llvm::Value *val )
|
|
{
|
|
auto op_size = llvm::IntegerType::get( *llvm_ctx, byte_size * 8 );
|
|
auto msb = ir_builder->CreateLShr( val, ( byte_size * 8 ) - 1 );
|
|
return ir_builder->CreateZExt( msb, llvm::IntegerType::get( *llvm_ctx, 64 ) );
|
|
}
|
|
|
|
llvm::Value *vmp_rtn_t::compute_zf( std::uint8_t byte_size, llvm::Value *val )
|
|
{
|
|
auto op_size = llvm::IntegerType::get( *llvm_ctx, byte_size * 8 );
|
|
auto is_zero = ir_builder->CreateICmpEQ( val, llvm::ConstantInt::get( op_size, 0 ) );
|
|
return ir_builder->CreateZExt( is_zero, llvm::IntegerType::get( *llvm_ctx, 64 ) );
|
|
}
|
|
|
|
llvm::Value *vmp_rtn_t::compute_pf( std::uint8_t byte_size, llvm::Value *val )
|
|
{
|
|
auto operand_size = llvm::IntegerType::get( *llvm_ctx, byte_size * 8 );
|
|
auto popcount_intrinsic = llvm::Intrinsic::getDeclaration( llvm_module, llvm::Intrinsic::ctpop,
|
|
{ llvm::IntegerType::get( *llvm_ctx, 64 ) } );
|
|
|
|
auto lower_bits = ir_builder->CreateIntCast( val, llvm::IntegerType::get( *llvm_ctx, 8 ), false );
|
|
auto extended_bits = ir_builder->CreateZExt( lower_bits, llvm::IntegerType::get( *llvm_ctx, 64 ) );
|
|
return ir_builder->CreateCall( popcount_intrinsic, { extended_bits } );
|
|
}
|
|
|
|
llvm::Value *vmp_rtn_t::combine_flags( llvm::Value *cf, llvm::Value *pf, llvm::Value *af, llvm::Value *zf,
|
|
llvm::Value *sf, llvm::Value *of )
|
|
{
|
|
auto shifted_pf = ir_builder->CreateShl( pf, 2, "shifted_pf", true, true );
|
|
auto shifted_af = ir_builder->CreateShl( llvm::ConstantInt::get( llvm::IntegerType::get( *llvm_ctx, 64 ), 0 ),
|
|
4, "shifted_af", true, true ); // treat af as zero
|
|
|
|
auto shifted_zf = ir_builder->CreateShl( zf, 6, "shifted_zf", true, true );
|
|
auto shifted_sf = ir_builder->CreateShl( sf, 7, "shifted_sf", true, true );
|
|
auto shifted_of = ir_builder->CreateShl( of, 11, "shifted_of", true, true );
|
|
auto or1 = ir_builder->CreateOr( cf, shifted_of );
|
|
auto or2 = ir_builder->CreateOr( or1, shifted_zf );
|
|
auto or3 = ir_builder->CreateOr( or2, shifted_sf );
|
|
auto or4 = ir_builder->CreateOr( or3, shifted_af );
|
|
auto or5 = ir_builder->CreateOr( or4, shifted_pf );
|
|
return ir_builder->CreateXor( or5, llvm::ConstantInt::get( llvm::IntegerType::get( *llvm_ctx, 64 ), 514 ) );
|
|
}
|
|
|
|
} // namespace vm
|