yetangitu/ghidra
1
0
Fork 0
mirror of https://github.com/NationalSecurityAgency/ghidra.git synced 2025-10-03 17:59:46 +02:00
Code Issues Releases Wiki Activity

Added distributing transform to ptrarith

Browse source
This commit is contained in:
caheckman 2020-04-29 12:25:58 -04:00
parent e6e88bf2be
commit 0dcf55b7c8
4 changed files with 147 additions and 90 deletions
Download patch file Download diff file Expand all files Collapse all files

51
Ghidra/Features/Decompiler/src/decompile/cpp/funcdata_op.cc
View file

@ -1009,6 +1009,57 @@ bool Funcdata::replaceLessequal(Funcdata &data,PcodeOp *op)
return true;
}
/// If a term has a multiplicative coefficient, but the underlying term is still additive,
/// in some situations we may need to distribute the coefficient before simplifying further.
/// The given PcodeOp is a INT_MULT where the second input is a constant. We also
/// know the first input is formed with INT_ADD. Distribute the coefficient to the INT_ADD inputs.
/// \param data is the function being analyzed
/// \param op is the given PcodeOp
/// \return \b truee if the action was performed
bool Funcdata::distributeIntMult(Funcdata &data,PcodeOp *op)
{
Varnode *newvn1,*newvn2,*newcvn;
PcodeOp *newop1, *newop2;
PcodeOp *addop = op->getIn(0)->getDef();
Varnode *vn0 = addop->getIn(0);
Varnode *vn1 = addop->getIn(1);
if ((vn0->isFree())&&(!vn0->isConstant())) return false;
if ((vn1->isFree())&&(!vn1->isConstant())) return false;
uintb coeff = op->getIn(1)->getOffset();
int4 size = op->getOut()->getSize();
// Do distribution
newop1 = data.newOp(2,op->getAddr());
data.opSetOpcode(newop1,CPUI_INT_MULT);
newvn1 = data.newUniqueOut(size,newop1);
newop2 = data.newOp(2,op->getAddr());
data.opSetOpcode(newop2,CPUI_INT_MULT);
newvn2 = data.newUniqueOut(size,newop2);
if (vn0->isConstant())
data.opSetInput(newop1, data.newConstant(size,vn0->getOffset()),0);
else
data.opSetInput(newop1, vn0, 0); // To first input of original add
newcvn = data.newConstant(size,coeff);
data.opSetInput(newop1, newcvn, 1);
data.opInsertBefore(newop1, op);
if (vn1->isConstant())
data.opSetInput(newop2, data.newConstant(size,vn1->getOffset()),0);
else
data.opSetInput(newop2, vn1, 0); // To second input of original add
newcvn = data.newConstant(size,coeff);
data.opSetInput(newop2, newcvn, 1);
data.opInsertBefore(newop2, op);
data.opSetInput( op, newvn1, 0); // new ADD's inputs are outputs of new MULTs
data.opSetInput( op, newvn2, 1);
data.opSetOpcode(op, CPUI_INT_ADD);
return true;
}
/// \brief Trace a boolean value to a set of PcodeOps that can be changed to flip the boolean value
///
/// The boolean Varnode is either the output of the given PcodeOp or the