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GP-4972 Multiplier of 0 indicates no INT_MULT or PTRADD is present

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This commit is contained in:
caheckman 2024-09-30 17:52:45 +00:00
parent a3d0b40f36
commit b8656612cd
2 changed files with 11 additions and 9 deletions
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2
Ghidra/Features/Decompiler/src/decompile/cpp/coreaction.cc
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@ -2729,7 +2729,7 @@ int4 ActionSetCasts::apply(Funcdata &data)
data.opUndoPtradd(op,true);
}
else if (opc == CPUI_PTRSUB) { // Check for PTRSUB that no longer fits pointer
if (!op->getIn(0)->getTypeReadFacing(op)->isPtrsubMatching(op->getIn(1)->getOffset(),0,1)) {
if (!op->getIn(0)->getTypeReadFacing(op)->isPtrsubMatching(op->getIn(1)->getOffset(),0,0)) {
if (op->getIn(1)->getOffset() == 0) {
data.opRemoveInput(op, 1);
data.opSetOpcode(op, CPUI_COPY);

18
Ghidra/Features/Decompiler/src/decompile/cpp/ruleaction.cc
View File

@ -6627,13 +6627,13 @@ void RulePtrsubUndo::getOpList(vector<uint4> &oplist) const
/// the sum of all the constants. Additionally pass back the biggest constant coefficient, for any term
/// formed with INT_MULT.
/// \param vn is the given root Varnode of the additive tree
/// \param multiplier will hold the biggest constant coefficient
/// \param multiplier will hold the biggest constant multiplier or 0, if no multiplier is present
/// \param maxLevel is the maximum depth to search in the tree
/// \return the sum of all constants in the additive expression
int8 RulePtrsubUndo::getConstOffsetBack(Varnode *vn,int8 &multiplier,int4 maxLevel)
{
multiplier = 1;
multiplier = 0;
int8 submultiplier;
if (vn->isConstant())
return vn->getOffset();
@ -6658,7 +6658,8 @@ int8 RulePtrsubUndo::getConstOffsetBack(Varnode *vn,int8 &multiplier,int4 maxLev
if (!cvn->isConstant()) return 0;
multiplier = cvn->getOffset();
getConstOffsetBack(op->getIn(0), submultiplier, maxLevel);
multiplier *= submultiplier; // Only contribute to the multiplier
if (submultiplier > 0)
multiplier *= submultiplier; // Only contribute to the multiplier
}
return retval;
}
@ -6669,12 +6670,12 @@ int8 RulePtrsubUndo::getConstOffsetBack(Varnode *vn,int8 &multiplier,int4 maxLev
/// constant value being added to the PTRSUB. Additionally pass back the biggest constant coefficient of any
/// multiplicative term in the expression.
/// \param op is the given PTRSUB
/// \param multiplier will hold the biggest multiplicative coefficient
/// \param multiplier will hold the biggest multiplicative coefficient or 0, if no INT_MULT or PTRADD is present.
int8 RulePtrsubUndo::getExtraOffset(PcodeOp *op,int8 &multiplier)
{
int8 extra = 0;
multiplier = 1;
multiplier = 0;
int8 submultiplier;
Varnode *outvn = op->getOut();
op = outvn->loneDescend();
@ -6696,9 +6697,10 @@ int8 RulePtrsubUndo::getExtraOffset(PcodeOp *op,int8 &multiplier)
if (invn->isConstant()) // Only contribute to the extra
extra += ptraddmult * (int8)invn->getOffset(); // if the index is constant
getConstOffsetBack(invn,submultiplier,DEPTH_LIMIT); // otherwise just contribute to multiplier
submultiplier *= ptraddmult;
if (submultiplier > multiplier)
multiplier = submultiplier;
if (submultiplier != 0)
ptraddmult *= submultiplier;
if (ptraddmult > multiplier)
multiplier = ptraddmult;
}
else {
break;