// check if addr falls into a data section, and is at least minAddr.
// the minAddr check exists for times when we are not sure if an address
// is a data reference or an immediate value; in some cases data is mapped
// at 0x0 and determining this could be tricky
static
bool addrIsInData(VA addr, NativeModulePtr m, VA &base, VA minAddr = 0x0 ) {
list<DataSection> §ions = m->getData();
list<DataSection>::iterator it = sections.begin();
// sanity check:
// assume no data references before minAddr.
if (addr < minAddr) {
return false;
}
if(sections.size() == 0) {
llvm::dbgs() << __FUNCTION__ << ": WARNING: no data sections!\n";
return false;
}
while( it != sections.end() ) {
DataSection &curSec = *it;
VA low = curSec.getBase();
VA high = low+curSec.getSize();
if( addr >= low && addr < high ) {
base = low;
return true;
}
++it;
}
return false;
}
static VA FindSymbolInModule(NativeModulePtr mod, const std::string &sym_name) {
for (auto &sym : mod->getEntryPoints()) {
if (sym.getName() == sym_name) {
return sym.getAddr();
}
}
return static_cast<VA>( -1);
}
static bool InsertDataSections(NativeModulePtr natMod, llvm::Module *M) {
auto &globaldata = natMod->getData();
//insert all global data before we insert the CFG
std::vector<DataSectionVar> gvars;
// pre-create references to all data sections
// as later we may have data references that are
// from one section into another
for (auto &dt : globaldata) {
std::stringstream ss;
ss << "data_" << std::hex << dt.getBase();
std::string bufferName = ss.str();
//report << "inserting global data section named ";
//report << bufferName << "\n";
std::cout << "inserting global data section named ";
std::cout << bufferName << std::endl;
auto st_opaque = llvm::StructType::create(M->getContext());
// Used to be PrivateLinkage, but that emitted
// .objs that would not link with MSVC
auto g = new llvm::GlobalVariable(
*M, st_opaque, dt.isReadOnly(),
llvm::GlobalVariable::InternalLinkage,
nullptr, bufferName);
gvars.push_back({&dt, st_opaque, g});
}
// actually populate the data sections
for (auto &var : gvars) {
//data we use to create LLVM values for this section
// secContents is the actual values we will be inserting
std::vector<llvm::Constant *> secContents;
// data_section_types is their types, which are needed to initialize
// the global variable
std::vector<llvm::Type *> data_section_types;
dataSectionToTypesContents(globaldata, *var.section, M, secContents,
data_section_types, true);
// fill in the opaque structure with actual members
var.opaque_type->setBody(data_section_types, true);
// create an initializer list using the now filled in opaque
// structure type
auto cst = llvm::ConstantStruct::get(var.opaque_type, secContents);
// align on pointer size boundary, max needed by SSE instructions
var.var->setAlignment(ArchPointerSize(M));
var.var->setInitializer(cst);
}
return true;
}
static bool addTableDataSection(NativeModulePtr natMod,
Module *M, VA &newVA, const T& table)
{
list<DataSection> &globaldata = natMod->getData();
list<DataSection>::const_iterator git = globaldata.begin();
// ensure we make this the last data section
newVA = 0;
while( git != globaldata.end() ) {
const DataSection &dt = *git;
uint64_t extent = dt.getBase() + dt.getSize();
if(newVA < extent) {
newVA = extent;
}
git++;
}
// skip a few
newVA += 4;
// create a new data section from the table
DataSection *ds = tableToDataSection(newVA, table);
// add to global data section list
globaldata.push_back(*ds);
// create the GlobalVariable
string bufferName = "data_0x" + to_string<VA>(newVA, hex);
StructType *st_opaque = StructType::create(M->getContext());
GlobalVariable *gv = new GlobalVariable(*M,
st_opaque,
true,
GlobalVariable::InternalLinkage,
NULL,
bufferName);
vector<Type*> data_section_types;
vector<Constant*> secContents;
dataSectionToTypesContents(globaldata,
*ds,
M,
secContents,
data_section_types,
false);
st_opaque->setBody(data_section_types, true);
Constant *cst = ConstantStruct::get(st_opaque, secContents);
gv->setAlignment(4);
gv->setInitializer(cst);
return true;
}
static bool LiftFunctionsIntoModule(NativeModulePtr natMod, llvm::Module *M) {
// populate functions
for (auto &func_info : natMod->get_funcs()) {
NativeFunctionPtr f = func_info.second;
if (!InsertFunctionIntoModule(natMod, f, M)) {
std::string fname = f->get_name();
std::cerr << "Could not insert function: " << fname
<< " into the LLVM module" << std::endl;
return false;
}
}
return true;
}
void PrintCFGFunctionList(const NativeModulePtr native_module, const std::string &architecture) noexcept {
std::ios::fmtflags original_stream_flags(std::cout.flags());
int address_digit_count = (architecture == "amd64" ? 16 : 8);
std::cout << "\nCFG Function List:\n";
const auto &function_map = native_module->get_funcs();
for (const auto &function_descriptor : function_map) {
VA virtual_address = function_descriptor.first;
const NativeFunctionPtr function = function_descriptor.second;
std::cout << " " << std::hex << std::setw(address_digit_count) << std::setfill('0') << virtual_address << " ";
std::cout << function->get_name() << std::endl;
}
std::cout.flags(original_stream_flags);
}
void doPrintModule(NativeModulePtr m) {
string pathBase = "./";
list<NativeFunctionPtr> mod_funcs = m->get_funcs();
list<NativeFunctionPtr>::iterator it = mod_funcs.begin();
for(; it != mod_funcs.end(); ++it) {
NativeFunctionPtr f = *it;
string n =
pathBase+to_string<uint64_t>(f->get_start(), hex) + ".dot";
ofstream out(n.c_str());
block_label_writer bgl(f);
CFG g = f->get_cfg();
write_graphviz(out, g, bgl);
}
return;
}
void RenameLiftedFunctions(NativeModulePtr natMod, llvm::Module *M,
const std::set<VA> &entry_point_pcs) {
// Rename the functions to have their 'nice' names, where available.
for (auto &f : natMod->get_funcs()) {
NativeFunctionPtr native_func = f.second;
if (entry_point_pcs.count(native_func->get_start())) {
continue;
}
auto sub_name = native_func->get_name();
auto F = M->getFunction(sub_name);
std::stringstream ss;
ss << "callback_" << sub_name;
if (!M->getFunction(ss.str())) {
auto &sym_name = native_func->get_symbol_name();
if (!sym_name.empty()) {
F->setName(sym_name);
}
}
}
}
static void InitExternalData(NativeModulePtr natMod, llvm::Module *M) {
for (auto dr : natMod->getExtDataRefs()) {
auto dsize = dr->getDataSize();
auto symname = dr->getSymbolName();
auto extType = llvm::ArrayType::get(llvm::Type::getInt8Ty(M->getContext()),
dsize);
auto gv = llvm::dyn_cast<llvm::GlobalValue>(
M->getOrInsertGlobal(symname, extType));
TASSERT(gv != nullptr, "Could not make global value!");
if (dr->isWeak()) {
gv->setLinkage(llvm::GlobalValue::ExternalWeakLinkage);
} else {
gv->setLinkage(llvm::GlobalValue::ExternalLinkage);
}
llvm::Triple triple(M->getTargetTriple());
if (llvm::Triple::Win32 == triple.getOS()) {
gv->setDLLStorageClass(llvm::GlobalValue::DLLImportStorageClass);
}
}
}
static void InitLiftedFunctions(NativeModulePtr natMod, llvm::Module *M) {
for (auto &f : natMod->get_funcs()) {
NativeFunctionPtr native_func = f.second;
auto fname = native_func->get_name();
auto F = M->getFunction(fname);
if (!F) {
F = llvm::dyn_cast<llvm::Function>(
M->getOrInsertFunction(fname, LiftedFunctionType()));
TASSERT(F != nullptr, "Could not insert function into module");
ArchSetCallingConv(M, F);
// make local functions 'static'
F->setLinkage(llvm::GlobalValue::InternalLinkage);
std::cout << "Inserted function: " << fname << std::endl;
} else {
std::cout << "Already inserted function: " << fname << ", skipping."
<< std::endl;
}
}
}
// Iterate over the list of external functions and insert them as
// global functions.
static void InitExternalCode(NativeModulePtr natMod, llvm::Module *M) {
for (auto e : natMod->getExtCalls()) {
auto conv = e->getCallingConvention();
auto argCount = e->getNumArgs();
auto symName = e->getSymbolName();
auto funcSign = e->getFunctionSignature();
// Create the function if it is not already there.
auto &C = M->getContext();
auto F = M->getFunction(symName);
if (F) {
continue;
}
if (ExternalCodeRef::McsemaCall == conv) {
// normal mcsema function prototypes
F = llvm::dyn_cast<llvm::Function>(M->getOrInsertFunction(
ArchNameMcSemaCall(symName), LiftedFunctionType()));
ArchSetCallingConv(M, F);
F->setLinkage(llvm::GlobalValue::ExternalLinkage);
continue;
}
std::vector<llvm::Type *> arguments;
llvm::Type *returnType = nullptr;
// Create arguments.
const auto Arch = SystemArch(M);
const auto OS = SystemOS(M);
for (auto i = 0; i < argCount; i++) {
if (_X86_64_ == Arch) {
if (llvm::Triple::Win32 == OS) {
if (funcSign.c_str()[i] == 'F') {
arguments.push_back(llvm::Type::getDoubleTy(C));
} else {
arguments.push_back(llvm::Type::getInt64Ty(C));
}
} else if (llvm::Triple::Linux == OS) {
arguments.push_back(llvm::Type::getInt64Ty(C));
} else {
TASSERT(false, "Unknown OS Type!");
}
} else {
arguments.push_back(llvm::Type::getInt32Ty(C));
}
}
//create function type
switch (e->getReturnType()) {
case ExternalCodeRef::NoReturn:
case ExternalCodeRef::VoidTy:
returnType = llvm::Type::getVoidTy(C);
break;
case ExternalCodeRef::Unknown:
case ExternalCodeRef::IntTy:
if (natMod->is64Bit()) {
returnType = llvm::Type::getInt64Ty(C);
} else {
returnType = llvm::Type::getInt32Ty(C);
}
break;
default:
throw TErr(
__LINE__, __FILE__,
"Encountered an unknown return type while translating function");
}
auto FTy = llvm::FunctionType::get(returnType, arguments, false);
if (e->isWeak()) {
F = llvm::Function::Create(FTy, llvm::GlobalValue::ExternalWeakLinkage,
symName, M);
} else {
F = llvm::Function::Create(FTy, llvm::GlobalValue::ExternalLinkage,
symName, M);
}
if (e->getReturnType() == ExternalCodeRef::NoReturn) {
F->setDoesNotReturn();
}
//set calling convention
if (natMod->is64Bit()) {
ArchSetCallingConv(M, F);
} else {
F->setCallingConv(getLLVMCC(conv));
}
}
}
