pair<AST::Ptr, bool> BoundFactsCalculator::ExpandAssignment(Assignment::Ptr assign) {
parsing_printf("Expand assignment : %s Instruction: %s\n", assign->format().c_str(), assign->insn()->format().c_str());
if (expandCache.find(assign) != expandCache.end()) {
AST::Ptr ast = expandCache[assign];
if (ast) return make_pair(ast, true); else return make_pair(ast, false);
} else {
pair<AST::Ptr, bool> expandRet = SymEval::expand(assign, false);
if (expandRet.second && expandRet.first) {
parsing_printf("Original expand: %s\n", expandRet.first->format().c_str());
AST::Ptr calculation = SimplifyAnAST(expandRet.first, assign->insn()->size());
expandCache[assign] = calculation;
} else {
expandCache[assign] = AST::Ptr();
}
return make_pair( expandCache[assign], expandRet.second );
}
}
SymEval::Retval_t SymEval::process(SliceNode::Ptr ptr,
Result_t &dbase,
std::set<Edge::Ptr> &skipEdges) {
bool failedTranslation;
bool skippedEdge = false;
bool skippedInput = false;
bool success = false;
std::map<const AbsRegion*, std::set<Assignment::Ptr> > inputMap;
expand_cerr << "Calling process on " << ptr->format() << endl;
// Don't try an expansion of a widen node...
if (!ptr->assign()) return WIDEN_NODE;
EdgeIterator begin, end;
ptr->ins(begin, end);
for (; begin != end; ++begin) {
SliceEdge::Ptr edge = boost::static_pointer_cast<SliceEdge>(*begin);
SliceNode::Ptr source = boost::static_pointer_cast<SliceNode>(edge->source());
// Skip this one to break a cycle.
if (skipEdges.find(edge) != skipEdges.end()) {
expand_cerr << "In process, skipping edge from "
<< source->format() << endl;
skippedEdge = true;
continue;
}
Assignment::Ptr assign = source->assign();
if (!assign) continue; // widen node
expand_cerr << "Assigning input " << edge->data().format()
<< " from assignment " << assign->format() << endl;
inputMap[&edge->data()].insert(assign);
}
expand_cerr << "\t Input map has size " << inputMap.size() << endl;
// All of the expanded inputs are in the parameter dbase
// If not (like this one), add it
AST::Ptr ast;
boost::tie(ast, failedTranslation) = SymEval::expand(ptr->assign());
// expand_cerr << "\t ... resulting in " << dbase.format() << endl;
// We have an AST. Now substitute in all of its predecessors.
for (std::map<const AbsRegion*, std::set<Assignment::Ptr> >::iterator iter = inputMap.begin();
iter != inputMap.end(); ++iter) {
// If we have multiple secondary definitions, we:
// if all definitions are equal, use the first
// otherwise, use nothing
AST::Ptr definition;
for (std::set<Assignment::Ptr>::iterator iter2 = iter->second.begin();
iter2 != iter->second.end(); ++iter2) {
AST::Ptr newDef = dbase[*iter2];
if (!definition) {
definition = newDef;
continue;
} else if (definition->equals(newDef)) {
continue;
} else {
// Not equal
definition = AST::Ptr();
skippedInput = true;
break;
}
}
// The region used by the current assignment...
const AbsRegion ® = *iter->first;
// Create an AST around this one
VariableAST::Ptr use = VariableAST::create(Variable(reg, ptr->addr()));
if (!definition) {
// Can happen if we're expanding out of order, and is generally harmless.
continue;
}
expand_cerr << "Before substitution: " << (ast ? ast->format() : "<NULL AST>") << endl;
if (!ast) {
expand_cerr << "Skipping substitution because of null AST" << endl;
} else {
ast = AST::substitute(ast, use, definition);
success = true;
}
expand_cerr << "\t result is " << (ast ? ast->format() : "<NULL AST>") << endl;
}
expand_cerr << "Result of substitution: " << ptr->assign()->format() << " == "
<< (ast ? ast->format() : "<NULL AST>") << endl;
// And attempt simplification again
ast = simplifyStack(ast, ptr->addr(), ptr->func(), ptr->block());
expand_cerr << "Result of post-substitution simplification: " << ptr->assign()->format() << " == "
<< (ast ? ast->format() : "<NULL AST>") << endl;
dbase[ptr->assign()] = ast;
if (failedTranslation) return FAILED_TRANSLATION;
else if (skippedEdge || skippedInput) return SKIPPED_INPUT;
else if (success) return SUCCESS;
else return FAILED;
}