yetangitu/ghidra
1
0
Fork 0
mirror of https://github.com/NationalSecurityAgency/ghidra.git synced 2025-10-05 02:39:44 +02:00
Code Issues Releases Wiki Activity

Adjustments to data-type propagation through INT_ADD

Browse source
This commit is contained in:
caheckman 2021-08-03 13:12:15 -04:00
parent 7f2ef251e1
commit 58558981d5
11 changed files with 257 additions and 125 deletions
Download patch file Download diff file Expand all files Collapse all files

30
Ghidra/Features/Decompiler/src/decompile/cpp/ruleaction.cc
View file

@ -6141,6 +6141,33 @@ bool RulePtrArith::verifyAddTreeBottom(PcodeOp *op,int4 slot)
return true;
}
/// \brief Test for other pointers in the ADD tree above the given op that might be a preferred base
///
/// This tests the condition of RulePushPtr, making sure that the given op isn't the lone descendant
/// of a pointer constructed by INT_ADD on another pointer (which would then be preferred).
/// \param op is the given op
/// \param slot is the input slot of the pointer
/// \return \b true if the indicated slot holds the preferred pointer
bool RulePtrArith::verifyPreferredPointer(PcodeOp *op,int4 slot)
{
Varnode *vn = op->getIn(slot);
// Check if RulePushPtr would apply here
if (op->getIn(1-slot)->getType()->getMetatype() != TYPE_PTR && vn->isWritten()) {
PcodeOp *preOp = vn->getDef();
if (preOp->code() == CPUI_INT_ADD) {
if (vn->loneDescend() == op) {
int ptrCount = 0;
if (preOp->getIn(0)->getType()->getMetatype() == TYPE_PTR) ptrCount += 1;
if (preOp->getIn(1)->getType()->getMetatype() == TYPE_PTR) ptrCount += 1;
if (ptrCount == 1)
return false; // RulePushPtr would apply, so we are not preferred
}
}
}
return true;
}
/// \class RulePtrArith
/// \brief Transform pointer arithmetic
///
@ -6180,11 +6207,14 @@ int4 RulePtrArith::applyOp(PcodeOp *op,Funcdata &data)
}
if (slot == op->numInput()) return 0;
if (!verifyAddTreeBottom(op, slot)) return 0;
if (!verifyPreferredPointer(op, slot)) return 0;
const TypePointer *tp = (const TypePointer *) ct;
ct = tp->getPtrTo(); // Type being pointed to
int4 unitsize = AddrSpace::addressToByteInt(1,tp->getWordSize());
if (ct->getSize() == unitsize) { // Degenerate case
if (op->getOut()->getType()->getMetatype() != TYPE_PTR) // Make sure pointer propagates thru INT_ADD
return 0;
vector<Varnode *> newparams;
newparams.push_back( op->getIn(slot) );
newparams.push_back( op->getIn(1-slot) );