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Adjustments to data-type propagation through INT_ADD

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This commit is contained in:
caheckman 2021-08-03 13:12:15 -04:00
parent 7f2ef251e1
commit 58558981d5
11 changed files with 257 additions and 125 deletions
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78
Ghidra/Features/Decompiler/src/decompile/cpp/varmap.cc
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@ -270,6 +270,7 @@ ScopeLocal::ScopeLocal(uint8 id,AddrSpace *spc,Funcdata *fd,Architecture *g) : S
{
space = spc;
deepestParamOffset = ~((uintb)0);
rangeLocked = false;
stackGrowsNegative = true;
restrictScope(fd);
@ -310,12 +311,14 @@ void ScopeLocal::collectNameRecs(void)
void ScopeLocal::resetLocalWindow(void)
{
stackGrowsNegative = fd->getFuncProto().isStackGrowsNegative();
deepestParamOffset = stackGrowsNegative ? ~((uintb)0) : 0;
if (rangeLocked) return;
localRange = fd->getFuncProto().getLocalRange();
const RangeList &localRange( fd->getFuncProto().getLocalRange() );
const RangeList &paramrange( fd->getFuncProto().getParamRange() );
stackGrowsNegative = fd->getFuncProto().isStackGrowsNegative();
RangeList newrange;
set<Range>::const_iterator iter;
@ -375,16 +378,13 @@ void ScopeLocal::markNotMapped(AddrSpace *spc,uintb first,int4 sz,bool parameter
last = spc->getHighest();
if (parameter) { // Everything above parameter
if (stackGrowsNegative) {
const Range *rng = localRange.getRange(spc,first);
if (rng != (const Range *)0)
first = rng->getFirst(); // Everything less is not mapped
if (first < deepestParamOffset)
deepestParamOffset = first;
}
else {
const Range *rng = localRange.getRange(spc,last);
if (rng != (const Range *)0)
last = rng->getLast(); // Everything greater is not mapped
if (first > deepestParamOffset)
deepestParamOffset = first;
}
sz = (last-first)+1;
}
Address addr(space,first);
// Remove any symbols under range
@ -427,6 +427,11 @@ string ScopeLocal::buildVariableName(const Address &addr,
s << 'X'; // Indicate local stack space allocated by caller
start = -start;
}
else {
if (deepestParamOffset + 1 > 1 && stackGrowsNegative == (addr.getOffset() < deepestParamOffset)) {
s << 'Y'; // Indicate unusual region of stack
}
}
s << dec << start;
return makeNameUnique(s.str());
}
@ -1095,6 +1100,9 @@ void ScopeLocal::markUnaliased(const vector<uintb> &alias)
EntryMap *rangemap = maptable[space->getIndex()];
if (rangemap == (EntryMap *)0) return;
list<SymbolEntry>::iterator iter,enditer;
set<Range>::const_iterator rangeIter, rangeEndIter;
rangeIter = getRangeTree().begin();
rangeEndIter = getRangeTree().end();
int4 alias_block_level = glb->alias_block_level;
bool aliason = false;
@ -1105,31 +1113,39 @@ void ScopeLocal::markUnaliased(const vector<uintb> &alias)
enditer = rangemap->end_list();
while(iter!=enditer) {
if ((i<alias.size()) && (alias[i] <= (*iter).getAddr().getOffset() + (*iter).getSize() - 1)) {
SymbolEntry &entry(*iter++);
uintb curoff = entry.getAddr().getOffset() + entry.getSize() - 1;
while ((i<alias.size()) && (alias[i] <= curoff)) {
aliason = true;
curalias = alias[i++];
}
else {
SymbolEntry &entry(*iter++);
Symbol *symbol = entry.getSymbol();
// Test if there is enough distance between symbol
// and last alias to warrant ignoring the alias
// NOTE: this is primarily to reset aliasing between
// stack parameters and stack locals
if (aliason && (entry.getAddr().getOffset()+entry.getSize() -1 - curalias > 0xffff))
aliason = false;
if (!aliason)
symbol->getScope()->setAttribute(symbol,Varnode::nolocalalias);
if (symbol->isTypeLocked() && alias_block_level != 0) {
if (alias_block_level == 3)
aliason = false; // For this level, all locked data-types block aliases
else {
type_metatype meta = symbol->getType()->getMetatype();
if (meta == TYPE_STRUCT)
aliason = false; // Only structures block aliases
else if (meta == TYPE_ARRAY && alias_block_level > 1)
aliason = false; // Only arrays (and structures) block aliases
}
// Aliases shouldn't go thru unmapped regions of the local variables
while(rangeIter != rangeEndIter) {
const Range &rng(*rangeIter);
if (rng.getSpace() == space) {
if (rng.getFirst() > curalias && curoff >= rng.getFirst())
aliason = false;
if (rng.getLast() >= curoff) break; // Check if symbol past end of mapped range
if (rng.getLast() > curalias) // If past end of range AND past last alias offset
aliason = false; // turn aliases off
}
++rangeIter;
}
Symbol *symbol = entry.getSymbol();
// Test if there is enough distance between symbol
// and last alias to warrant ignoring the alias
// NOTE: this is primarily to reset aliasing between
// stack parameters and stack locals
if (aliason && (curoff - curalias > 0xffff)) aliason = false;
if (!aliason) symbol->getScope()->setAttribute(symbol,Varnode::nolocalalias);
if (symbol->isTypeLocked() && alias_block_level != 0) {
if (alias_block_level == 3)
aliason = false; // For this level, all locked data-types block aliases
else {
type_metatype meta = symbol->getType()->getMetatype();
if (meta == TYPE_STRUCT)
aliason = false; // Only structures block aliases
else if (meta == TYPE_ARRAY && alias_block_level > 1) aliason = false;// Only arrays (and structures) block aliases
}
}
}