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Fine tuning test for redundant COPY pair

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This commit is contained in:
caheckman 2019-04-26 15:34:11 -04:00
parent 9f6dd7edfe
commit ec9e31483a
1 changed files with 9 additions and 21 deletions
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30
Ghidra/Features/Decompiler/src/decompile/cpp/merge.cc
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@ -938,32 +938,20 @@ bool Merge::checkCopyPair(HighVariable *high,PcodeOp *domOp,PcodeOp *subOp)
FlowBlock *subBlock = subOp->getParent();
if (!domBlock->dominates(subBlock))
return false;
int4 domId = domBlock->getIndex();
int4 subId = subBlock->getIndex();
Cover range;
range.addDefPoint(domOp->getOut());
range.addRefPoint(subOp,subOp->getIn(0));
Varnode *inVn = domOp->getIn(0);
// Look for high Varnodes in the range
for(int4 i=0;i<high->numInstances();++i) {
Varnode *vn = high->getInstance(i);
if (!vn->isWritten()) continue;
PcodeOp *op = vn->getDef();
if (op == domOp) continue;
if (op == subOp) continue;
int4 index = op->getParent()->getIndex();
if (index == domId) { // Assignment same block as domOp
if (op->getSeqNum().getOrder() > domOp->getSeqNum().getOrder())
return false;
if (op->code() == CPUI_COPY) { // If the write is not a COPY
if (op->getIn(0) == inVn) continue; // from the same Varnode as domOp and subOp
}
if (index == subId) { // Assignment same block as subOp
if (op->getSeqNum().getOrder() < subOp->getSeqNum().getOrder())
return false;
}
}
// All cover blocks in between domOp and subOp must be empty
if (subBlock != domBlock) {
high->updateCover();
subBlock = subBlock->getImmedDom(); // Don't need to check first block
while(subBlock != domBlock) { // Don't need to check last block
if (!high->wholecover.getCoverBlock(subBlock->getIndex()).empty())
return false;
subBlock = subBlock->getImmedDom();
if (range.contain(op, 1)) { // and if write is contained in range between domOp and subOp
return false; // it is intervening and subOp is not redundant
}
}
return true;