static bool parseJumpIndexTable(ExecutableContainer *c,
InstPtr index_insn,
const vector<VA> &jmptable_entries,
raw_ostream &out)
{
VA reloc_offset = index_insn->get_reloc_offset();
if (reloc_offset == 0) {
out << "Unsupported jump index write; no relocation\n";
// this jump index probably doesn't use a table
return false;
}
VA addrInInst = index_insn->get_loc() + reloc_offset;
VA indexTableEntry;
VA symbolSize;
if(!c->relocate_addr(addrInInst, indexTableEntry, symbolSize)) {
out << "Not a jump index table: can't relocate relocation in index insn\n";
// can't relocate, something bad happened
return false;
}
// assume we always index the start of the index table
// ... might not be correct
// this means we set initial entry to zero, the first element
int initial_entry = 0;
uint8_t b;
int bindex = 0;
// loop while all the bytes we read can be table indexes
vector<uint8_t> index_entries;
while( (indexTableEntry+bindex) < c->getExtent() ) {
c->readByte(indexTableEntry+bindex, &b);
if (b > jmptable_entries.size())
{
break;
}
out << "Read index table byte: " << to_string<uint32_t>((uint32_t)b, hex) << "\n";
index_entries.push_back(b);
bindex++;
}
JumpIndexTable *jit = new JumpIndexTable(index_entries, initial_entry);
index_insn->set_jump_index_table(JumpIndexTablePtr(jit));
return true;
}
//GENERIC_TRANSLATION_32MI(MOV32mi,
// doMIMov<32>(ip, block, ADDR(0), OP(5)),
// doMIMov<32>(ip, block, STD_GLOBAL_OP(0), OP(5)),
// doMIMovV<32>(ip, block, ADDR_NOREF(0), GLOBAL_DATA_OFFSET(block, natM, ip))
// )
//
static InstTransResult translate_MOV32mi(NativeModulePtr natM, BasicBlock *&block, InstPtr ip, MCInst &inst) {
InstTransResult ret;
Function *F = block->getParent();
if( ip->has_call_tgt() ) {
Value *callback_fn = makeCallbackForLocalFunction(
block->getParent()->getParent(),
ip->get_call_tgt(0)
);
Value *addrInt = new PtrToIntInst(
callback_fn, llvm::Type::getInt32Ty(block->getContext()), "", block);
ret = doMIMovV<32>(ip, block, ADDR(0), addrInt);
}
else if( ip->is_data_offset() ) {
if( ip->get_reloc_offset() < OP(5).getOffset() ) {
doMIMov<32>(ip, block, STD_GLOBAL_OP(0), OP(5));
} else {
doMIMovV<32>(ip, block, ADDR_NOREF(0), GLOBAL_DATA_OFFSET(block, natM, ip));
}
ret = ContinueBlock;
} else {
ret = doMIMov<32>(ip, block, ADDR(0), OP(5));
}
return ret;
}
static bool handlePossibleJumpTable(ExecutableContainer *c,
NativeBlockPtr B,
InstPtr jmpinst,
VA curAddr,
stack<VA> &funcs,
stack<VA> &blockChildren,
raw_ostream &out) {
LASSERT(jmpinst->get_inst().getOpcode() == X86::JMP32m,
"handlePossibleJumpTable needs a JMP32m opcode" );
// is this a jump table, step 0
// does this instruction have a relocation?
VA reloc_offset = jmpinst->get_reloc_offset();
if (reloc_offset == 0) {
out << "Not a jump table: no relocation in JMP32m\n";
// bail, this is not a jump table
return false;
}
// this relocation has to point to a relocation
VA addrInInst = curAddr + reloc_offset;
VA jmpTableEntry, someFunction;
if(!c->relocate_addr(addrInInst, jmpTableEntry)) {
out << "Not a jump table: can't relocate relocation in JMP32m\n";
// can't relocate, something bad happened
return false;
}
if(!c->relocate_addr(jmpTableEntry, someFunction)) {
// could not relocate the default jump table entry.
// not good
out << "Not a jump table: can't relocate first jump table entry\n";
return false;
}
bool is_reloc_code = isAddrOfType(c, someFunction, ExecutableContainer::CodeSection);
if(!is_reloc_code) {
// jump table entry not point to code
out << "Not a jump table: first entry doesn't point to code\n";
return false;
}
// read jump table entries and add them as new function
// entry points
vector<VA> jmptable_entries;
int new_funs;
int original_zero;
// this reads negative jump table indexes, but vectors are not negative
// indexed. the negative most, which should be the new index 0, is now
// index N. Reverse the vector so it will be index 0, and save the current
// size as the original zeroth element
new_funs = addJmpTableEntries(c, jmptable_entries, jmpTableEntry, -4, out);
std::reverse(jmptable_entries.begin(), jmptable_entries.end());
out << "Added: " << to_string<int>(new_funs, dec) << " functions to jmptable\n";
original_zero = new_funs;
// add original entry at the zero position
jmptable_entries.push_back(someFunction);
out << "Added JMPTABLE entry [" << to_string<uint32_t>(jmpTableEntry, hex)
<< "] => " << to_string<uint32_t>(someFunction, hex) << "\n";
// add the positive table entries
new_funs = addJmpTableEntries(c, jmptable_entries, jmpTableEntry, 4, out);
out << "Added: " << to_string<int>(new_funs, dec) << " functions to jmptable\n";
// associate instruction with jump table
JumpTable *jt = new JumpTable(jmptable_entries, original_zero);
jmpinst->set_jump_table(JumpTablePtr(jt));
stack<VA> *toPush = NULL;
// if this jump table is in the format
// jmp [reg*4+imm32], then it is conformant
// and we can turn it into an llvm switch();
bool is_conformant = isConformantJumpInst(jmpinst);
if(is_conformant) {
toPush = &blockChildren;
out << "GOT A CONFORMANT JUMP INST\n";
} else {
toPush = &funcs;
}
// add these jump table entries as new entry points
for(std::vector<VA>::const_iterator itr = jmptable_entries.begin();
itr != jmptable_entries.end();
itr++)
{
out << "Adding block via jmptable: " << to_string<VA>(*itr, hex) << "\n";
toPush->push(*itr);
if(is_conformant) {
B->add_follow(*itr);
}
}
processJumpIndexTable(c, B, jmpinst, jmptable_entries, out);
return true;
}