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Code Issues Releases Wiki Activity

added RuleOrConsume

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This commit is contained in:
caheckman 2019-10-29 09:27:42 -04:00
parent 992d32dd87
commit 40d840085f
3 changed files with 40 additions and 0 deletions
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1
Ghidra/Features/Decompiler/src/decompile/cpp/coreaction.cc
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@ -4482,6 +4482,7 @@ void universal_action(Architecture *conf)
actprop->addRule( new RuleIdentityEl("analysis") );
actprop->addRule( new RuleOrMask("analysis") );
actprop->addRule( new RuleAndMask("analysis") );
actprop->addRule( new RuleOrConsume("analysis") );
actprop->addRule( new RuleOrCollapse("analysis") );
actprop->addRule( new RuleAndOrLump("analysis") );
actprop->addRule( new RuleShiftBitops("analysis") );

29
Ghidra/Features/Decompiler/src/decompile/cpp/ruleaction.cc
View file

@ -390,6 +390,35 @@ int4 RuleAndMask::applyOp(PcodeOp *op,Funcdata &data)
return 1;
}
/// \class RuleOrConsume
/// \brief Simply OR with unconsumed input: `V = A | B => V = B if nzm(A) & consume(V) == 0
void RuleOrConsume::getOpList(vector<uint4> &oplist) const
{
oplist.push_back(CPUI_INT_OR);
oplist.push_back(CPUI_INT_XOR);
}
int4 RuleOrConsume::applyOp(PcodeOp *op,Funcdata &data)
{
Varnode *outvn = op->getOut();
int4 size = outvn->getSize();
if (size > sizeof(uintb)) return 0; // FIXME: uintb should be arbitrary precision
uintb consume = outvn->getConsume();
if ((consume & op->getIn(0)->getNZMask()) == 0) {
data.opRemoveInput(op,0);
data.opSetOpcode(op, CPUI_COPY);
return 1;
}
else if ((consume & op->getIn(1)->getNZMask()) == 0) {
data.opRemoveInput(op,1);
data.opSetOpcode(op, CPUI_COPY);
return 1;
}
return 0;
}
/// \class RuleOrCollapse
/// \brief Collapse unnecessary INT_OR
///

10
Ghidra/Features/Decompiler/src/decompile/cpp/ruleaction.hh
View file

@ -128,6 +128,16 @@ public:
virtual void getOpList(vector<uint4> &oplist) const;
virtual int4 applyOp(PcodeOp *op,Funcdata &data);
};
class RuleOrConsume : public Rule {
public:
RuleOrConsume(const string &g) : Rule(g, 0, "orconsume") {} ///< Constructor
virtual Rule *clone(const ActionGroupList &grouplist) const {
if (!grouplist.contains(getGroup())) return (Rule *)0;
return new RuleOrConsume(getGroup());
}
virtual void getOpList(vector<uint4> &oplist) const;
virtual int4 applyOp(PcodeOp *op,Funcdata &data);
};
class RuleOrCollapse : public Rule {
public:
RuleOrCollapse(const string &g) : Rule(g, 0, "orcollapse") {} ///< Constructor