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Code Issues Releases Wiki Activity

Attempt at adjusting processing of free stores

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This commit is contained in:
caheckman 2020-03-31 14:06:27 -04:00
parent 7dea6d1f41
commit 6a15520aa5
2 changed files with 30 additions and 9 deletions
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26
Ghidra/Features/Decompiler/src/decompile/cpp/heritage.cc
View file

@ -800,10 +800,15 @@ bool Heritage::protectFreeStores(AddrSpace *spc,vector<PcodeOp *> &freeStores)
++iter;
if (op->isDead()) continue;
Varnode *vn = op->getIn(1);
if (vn->isWritten()) {
PcodeOp *copyOp = vn->getDef();
if (copyOp->code() == CPUI_COPY)
vn = copyOp->getIn(0);
while (vn->isWritten()) {
PcodeOp *defOp = vn->getDef();
OpCode opc = defOp->code();
if (opc == CPUI_COPY)
vn = defOp->getIn(0);
else if (opc == CPUI_INT_ADD && defOp->getIn(1)->isConstant())
vn = defOp->getIn(0);
else
break;
}
if (vn->isFree() && vn->getSpace() == spc) {
fd->opMarkSpacebasePtr(op); // Mark op as spacebase STORE, even though we're not sure
@ -913,8 +918,17 @@ bool Heritage::discoverIndexedStackPointers(AddrSpace *spc,vector<PcodeOp *> &fr
}
case CPUI_STORE:
{
if (curNode.traversals != 0) {
generateStoreGuard(curNode, op, spc);
if (op->getIn(1) == curNode.vn) { // Make sure the STORE pointer comes from our path
if (curNode.traversals != 0) {
generateStoreGuard(curNode, op, spc);
}
else {
// If there were no traversals (of non-constant ADD or MULTIEQUAL) then the
// pointer is equal to the stackpointer plus a constant (through an indirect is possible)
// This will likely get resolved in the next heritage pass, but we leave the
// spacebaseptr mark on, so that that the indirects don't get removed
fd->opMarkSpacebasePtr(op);
}
}
break;
}

13
Ghidra/Features/Decompiler/src/decompile/cpp/ruleaction.cc
View file

@ -2932,10 +2932,17 @@ int4 RuleIndirectCollapse::applyOp(PcodeOp *op,Funcdata &data)
return 0;
}
else if (indop->usesSpacebasePtr()) {
const LoadGuard *guard = data.getStoreGuard(indop);
if (guard != (const LoadGuard *)0) {
if (guard->isGuarded(op->getOut()->getAddr()))
if (indop->code() == CPUI_STORE) {
const LoadGuard *guard = data.getStoreGuard(indop);
if (guard != (const LoadGuard *)0) {
if (guard->isGuarded(op->getOut()->getAddr()))
return 0;
}
else {
// A marked STORE that is not guarded should eventually get converted to a COPY
// so we keep the INDIRECT until that happens
return 0;
}
}
}
else