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GP-1518 Decompiler support for unions

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This commit is contained in:
caheckman 2021-11-19 14:39:42 -05:00
parent 53e2c4dc4f
commit 3fdbbbb231
65 changed files with 5119 additions and 1068 deletions
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76
Ghidra/Features/Decompiler/src/decompile/cpp/database.cc
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@ -127,20 +127,18 @@ bool SymbolEntry::updateType(Varnode *vn) const
Datatype *SymbolEntry::getSizedType(const Address &inaddr,int4 sz) const
{
Datatype *last,*cur;
uintb off;
if (isDynamic())
off = offset;
else
off = (inaddr.getOffset() - addr.getOffset()) + offset;
cur = symbol->getType();
Datatype *cur = symbol->getType();
do {
last = cur;
if (offset == 0 && cur->getSize() == sz)
return cur;
cur = cur->getSubType(off,&off);
} while(cur != (Datatype *)0);
if (last->getSize() == sz)
return last;
// else {
// This case occurs if the varnode is a "partial type" of some sort
// This PROBABLY means the varnode shouldn't be considered addrtied
@ -400,7 +398,7 @@ void Symbol::restoreXmlHeader(const Element *el)
{
name.clear();
category = -1;
category = no_category;
symbolId = 0;
for(int4 i=0;i<el->getNumAttributes();++i) {
const string &attName(el->getAttributeName(i));
@ -488,7 +486,7 @@ void Symbol::restoreXmlHeader(const Element *el)
break;
}
}
if (category == 0) {
if (category == function_parameter) {
istringstream s2(el->getAttributeValue("index"));
s2.unsetf(ios::dec | ios::hex | ios::oct);
s2 >> catindex;
@ -649,7 +647,7 @@ EquateSymbol::EquateSymbol(Scope *sc,const string &nm,uint4 format,uintb val)
: Symbol(sc, nm, (Datatype *)0)
{
value = val;
category = 1;
category = equate;
type = sc->getArch()->types->getBase(1,TYPE_UNKNOWN);
dispflags |= format;
}
@ -705,6 +703,49 @@ void EquateSymbol::restoreXml(const Element *el)
type = types->getBase(1,TYPE_UNKNOWN);
}
/// Create a symbol that forces a particular field of a union to propagate
///
/// \param sc is the scope owning the new symbol
/// \param nm is the name of the symbol
/// \param unionDt is the union data-type being forced
/// \param fldNum is the particular field to force (-1 indicates the whole union)
UnionFacetSymbol::UnionFacetSymbol(Scope *sc,const string &nm,Datatype *unionDt,int4 fldNum)
: Symbol(sc, nm, unionDt)
{
fieldNum = fldNum;
category = union_facet;
}
void UnionFacetSymbol::saveXml(ostream &s) const
{
s << "<facetsymbol";
saveXmlHeader(s);
a_v_i(s,"field",fieldNum);
s << ">\n";
saveXmlBody(s);
s << "</facetsymbol>\n";
}
void UnionFacetSymbol::restoreXml(const Element *el)
{
restoreXmlHeader(el);
istringstream s(el->getAttributeValue("field"));
s.unsetf(ios::dec | ios::hex | ios::oct);
s >> fieldNum;
const List &list(el->getChildren());
restoreXmlBody(list.begin());
Datatype *testType = type;
if (testType->getMetatype() == TYPE_PTR)
testType = ((TypePointer *)testType)->getPtrTo();
if (testType->getMetatype() != TYPE_UNION)
throw LowlevelError("<unionfacetsymbol> does not have a union type");
if (fieldNum < -1 || fieldNum >= testType->numDepend())
throw LowlevelError("<unionfacetsymbol> field attribute is out of bounds");
}
/// Label symbols don't really have a data-type, so we just put
/// a size 1 placeholder.
void LabSymbol::buildType(void)
@ -1556,6 +1597,8 @@ Symbol *Scope::addMapSym(const Element *el)
sym = new LabSymbol(owner);
else if (symname == "externrefsymbol")
sym = new ExternRefSymbol(owner);
else if (symname == "facetsymbol")
sym = new UnionFacetSymbol(owner);
else
throw LowlevelError("Unknown symbol type: "+symname);
try { // Protect against duplicate scope errors
@ -1711,9 +1754,9 @@ string Scope::buildDefaultName(Symbol *sym,int4 &base,Varnode *vn) const
if (!vn->isAddrTied() && fd != (Funcdata *)0)
usepoint = vn->getUsePoint(*fd);
HighVariable *high = vn->getHigh();
if (sym->getCategory() == 0 || high->isInput()) {
if (sym->getCategory() == Symbol::function_parameter || high->isInput()) {
int4 index = -1;
if (sym->getCategory()==0)
if (sym->getCategory()==Symbol::function_parameter)
index = sym->getCategoryIndex()+1;
return buildVariableName(vn->getAddr(),usepoint,sym->getType(),index,vn->getFlags() | Varnode::input);
}
@ -1724,7 +1767,7 @@ string Scope::buildDefaultName(Symbol *sym,int4 &base,Varnode *vn) const
Address addr = entry->getAddr();
Address usepoint = entry->getFirstUseAddress();
uint4 flags = usepoint.isInvalid() ? Varnode::addrtied : 0;
if (sym->getCategory() == 0) { // If this is a parameter
if (sym->getCategory() == Symbol::function_parameter) {
flags |= Varnode::input;
int4 index = sym->getCategoryIndex() + 1;
return buildVariableName(addr, usepoint, sym->getType(), index, flags);
@ -1958,7 +2001,7 @@ void ScopeInternal::categorySanity(void)
for(int4 j=0;j<list.size();++j) {
Symbol *sym = list[j];
if (sym == (Symbol *)0) continue;
setCategory(sym,-1,0); // Set symbol to have no category
setCategory(sym,Symbol::no_category,0);
}
}
}
@ -2004,7 +2047,7 @@ void ScopeInternal::clearUnlocked(void)
if (sym->isSizeTypeLocked())
resetSizeLockType(sym);
}
else if (sym->getCategory() == 1) {
else if (sym->getCategory() == Symbol::equate) {
// Note we treat EquateSymbols as locked for purposes of this method
// as a typelock (which traditionally prevents a symbol from being cleared)
// does not make sense for an equate
@ -2579,8 +2622,11 @@ void ScopeInternal::saveXml(ostream &s) const
int4 symbolType = 0;
if (!sym->mapentry.empty()) {
const SymbolEntry &entry( *sym->mapentry.front() );
if (entry.isDynamic())
symbolType = (sym->getCategory() == 1) ? 2 : 1;
if (entry.isDynamic()) {
if (sym->getCategory() == Symbol::union_facet)
continue; // Don't save override
symbolType = (sym->getCategory() == Symbol::equate) ? 2 : 1;
}
}
s << "<mapsym";
if (symbolType == 1)