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GP-4890 Add support for mixed size extensions in cancelExtensions

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This commit is contained in:
caheckman 2024-09-03 21:55:18 +00:00
parent 3d7139e0a8
commit 8ab71bb73c
2 changed files with 38 additions and 4 deletions
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41
Ghidra/Features/Decompiler/src/decompile/cpp/ruleaction.cc
View file

@ -4129,6 +4129,24 @@ void RuleSubCommute::getOpList(vector<uint4> &oplist) const
oplist.push_back(CPUI_SUBPIECE); oplist.push_back(CPUI_SUBPIECE);
} }
/// \brief Shrink the output of an extension to the given size
///
/// The output of either a INT_ZEXT or INT_SEXT is replaced with a smaller/truncated Varnode.
/// \param extOp is the INT_ZEXT or INT_SEXT
/// \param maxSize is the given size to shrink the output to
/// \param data is the function owning the extension
/// \return the new smaller Varnode
Varnode *RuleSubCommute::shortenExtension(PcodeOp *extOp,int4 maxSize,Funcdata &data)
{
Varnode *origOut = extOp->getOut();
Address addr = origOut->getAddr();
if (addr.isBigEndian())
addr = addr + (origOut->getSize() - maxSize);
data.opUnsetOutput(extOp);
return data.newVarnodeOut(maxSize, addr, extOp);
}
/// \brief Eliminate input extensions on given binary PcodeOp /// \brief Eliminate input extensions on given binary PcodeOp
/// ///
/// Make some basic checks. Replace the input and output Varnodes with smaller sizes. /// Make some basic checks. Replace the input and output Varnodes with smaller sizes.
@ -4141,13 +4159,28 @@ void RuleSubCommute::getOpList(vector<uint4> &oplist) const
bool RuleSubCommute::cancelExtensions(PcodeOp *longform,PcodeOp *subOp,Varnode *ext0In,Varnode *ext1In,Funcdata &data) bool RuleSubCommute::cancelExtensions(PcodeOp *longform,PcodeOp *subOp,Varnode *ext0In,Varnode *ext1In,Funcdata &data)
{ {
if (ext0In->getSize() != ext1In->getSize()) return false; // Sizes must match int4 maxSize;
if (ext0In->isFree()) return false; // Must be able to propagate inputs
if (ext1In->isFree()) return false;
Varnode *outvn = longform->getOut(); Varnode *outvn = longform->getOut();
if (outvn->loneDescend() != subOp) return false; // Must be exactly one output to SUBPIECE if (outvn->loneDescend() != subOp) return false; // Must be exactly one output to SUBPIECE
if (ext0In->getSize() == ext1In->getSize()) {
maxSize = ext0In->getSize();
if (ext0In->isFree()) return false; // Must be able to propagate inputs
if (ext1In->isFree()) return false;
}
else if (ext0In->getSize() < ext1In->getSize()) {
maxSize = ext1In->getSize();
if (ext1In->isFree()) return false;
if (longform->getIn(0)->loneDescend() != longform) return false;
ext0In = shortenExtension(longform->getIn(0)->getDef(), maxSize, data);
}
else {
maxSize = ext0In->getSize();
if (ext0In->isFree()) return false;
if (longform->getIn(1)->loneDescend() != longform) return false;
ext1In = shortenExtension(longform->getIn(1)->getDef(), maxSize, data);
}
data.opUnsetOutput(longform); data.opUnsetOutput(longform);
outvn = data.newUniqueOut(ext0In->getSize(),longform); // Create truncated form of longform output outvn = data.newUniqueOut(maxSize,longform); // Create truncated form of longform output
data.opSetInput(longform,ext0In,0); data.opSetInput(longform,ext0In,0);
data.opSetInput(longform,ext1In,1); data.opSetInput(longform,ext1In,1);
data.opSetInput(subOp,outvn,0); data.opSetInput(subOp,outvn,0);

1
Ghidra/Features/Decompiler/src/decompile/cpp/ruleaction.hh
View file

@ -811,6 +811,7 @@ public:
} }
virtual void getOpList(vector<uint4> &oplist) const; virtual void getOpList(vector<uint4> &oplist) const;
virtual int4 applyOp(PcodeOp *op,Funcdata &data); virtual int4 applyOp(PcodeOp *op,Funcdata &data);
static Varnode *shortenExtension(PcodeOp *extOp,int4 maxSize,Funcdata &data);
static bool cancelExtensions(PcodeOp *longform,PcodeOp *subOp,Varnode *ext0In,Varnode *ext1In,Funcdata &data); static bool cancelExtensions(PcodeOp *longform,PcodeOp *subOp,Varnode *ext0In,Varnode *ext1In,Funcdata &data);
}; };
class RuleConcatCommute : public Rule { class RuleConcatCommute : public Rule {