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EFA: improve robustness against non-existent FSO

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This commit is contained in:
Ivan Krysak
2024-03-18 17:23:57 +01:00
committed by Alessandro Di Federico
parent 9af0200b90
commit dace089658
1 changed files with 7 additions and 5 deletions
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lib/EarlyFunctionAnalysis/CFGAnalyzer.cpp
+7 -5
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@@ -776,7 +776,6 @@ FunctionSummary CFGAnalyzer::milkInfo(OutlinedFunction *OutlinedFunction,
Block.ID(),
MetaAddress::invalid(),
CalledSymbol);
revng_assert(Summary->ElectedFSO.has_value());
Argument = CI->getArgOperand(StackPointerOffsetIndex);
auto *StackPointerOffset = dyn_cast<ConstantInt>(Argument);
@@ -795,14 +794,17 @@ FunctionSummary CFGAnalyzer::milkInfo(OutlinedFunction *OutlinedFunction,
IBIResult.emplace_back(CI, makeIndirectEdge(BrokenReturn));
}
} else if (IsTailCall) {
// We have a tail call for which the FSO is known! We can exploit this
// to know this function's FSO!
TailCalls.emplace_back(CI, FSO + *Summary->ElectedFSO, Summary);
if (Summary->ElectedFSO.has_value()) {
// We have a tail call for which the FSO is known! We can exploit this
// to know this function's FSO!
TailCalls.emplace_back(CI, FSO + *Summary->ElectedFSO, Summary);
}
} else {
Argument = CI->getArgOperand(ReturnValuePreservedIndex);
auto *ReturnValuePreserved = dyn_cast<ConstantInt>(Argument);
if (ReturnValuePreserved != nullptr
and getLimitedValue(ReturnValuePreserved) == 0) {
and getLimitedValue(ReturnValuePreserved) == 0
and Summary->ElectedFSO.has_value()) {
// Here the stack pointer offset is known and the value of the
// return address (in the link register/top of the stack) has been
// preserved.