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Added spacebase references to the symbol linking process

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This commit is contained in:
caheckman 2019-12-05 14:40:23 -05:00
parent c886f01587
commit 917d2492e4
5 changed files with 85 additions and 17 deletions
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29
Ghidra/Features/Decompiler/src/decompile/cpp/funcdata_varnode.cc
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@ -973,6 +973,35 @@ Symbol *Funcdata::linkSymbol(Varnode *vn)
return sym;
}
/// A reference to a symbol (i.e. &varname) is typically stored as a PTRSUB operation, where the
/// first input Varnode is a \e spacebase Varnode indicating whether the symbol is on the \e stack or at
/// a \e global RAM location. The second input Varnode is a constant encoding the address of the symbol.
/// This method takes this constant Varnode, recovers the symbol it is referring to, and stores
/// on the HighVariable object attached to the Varnode.
/// \param vn is the constant Varnode (second input) to a PTRSUB operation
/// \return the symbol being referred to or null
Symbol *Funcdata::linkSymbolReference(Varnode *vn)
{
PcodeOp *op = vn->loneDescend();
Varnode *in0 = op->getIn(0);
TypePointer *ptype = (TypePointer *)in0->getHigh()->getType();
if (ptype->getMetatype() != TYPE_PTR) return (Symbol *)0;
TypeSpacebase *sb = (TypeSpacebase *)ptype->getPtrTo();
if (sb->getMetatype() != TYPE_SPACEBASE)
return (Symbol *)0;
Scope *scope = sb->getMap();
Address addr = sb->getAddress(vn->getOffset(),in0->getSize(),op->getAddr());
if (addr.isInvalid())
throw LowlevelError("Unable to generate proper address from spacebase");
SymbolEntry *entry = scope->queryContainer(addr,1,Address());
if (entry == (SymbolEntry *)0)
return (Symbol *)0;
int4 off = (int4)(addr.getOffset() - entry->getAddr().getOffset()) + entry->getOffset();
vn->getHigh()->setSymbol(entry->getSymbol(), off);
return entry->getSymbol();
}
/// If a Symbol is already attached, no change is made. Otherwise a special \e dynamic Symbol is
/// created that is associated with the Varnode via a hash of its local data-flow (rather
/// than its storage address).