Problem in initialization Seeds #633
Description
- [√] I have searched open and closed issues for duplicates
- [√] I made sure that I am not using an old project version (DO: pull Phasar, update git submodules, rebuild the project and check if the bug is still there)
// The %0 is the taint seed.
define void @foo(i32 %0){
call void @llvm.dbg.value(metadata i32 %0, metadata !21, metadata !DIExpression()), !dbg !22;
%1 = add nsw i32 %0, 1;
%2 = add nsw i32 %1, 1;
call void @tt(i32 %3);
%5 = add nsw i32 %4, 1;
}
The taint fact value has some mistakes in the no call instruction:
N: %1 = add nsw i32 %0, 1;
----------------------------------------------------
D: @zero_value | V: BOTTOM
D: i32 %0 | V: BOTTOM
N: %2 = add nsw i32 %1, 1;
-----------------------------------------------------
D: @zero_value | V: BOTTOM
D: i32 %0 | V: TOP
%1 = add nsw i32 %0, 1; | V: TOP (should be BOTTOM)
N: call void @tt(i32 %3);
-----------------------------------------------------
D: @zero_value | V: BOTTOM
D: i32 %0 | V: BOTTOM
%1 = add nsw i32 %0, 1; | V: BOTTOM
N: %5 = add nsw i32 %4, 1;
-----------------------------------------------------
D: @zero_value | V: BOTTOM
D: i32 %0 | V: TOP
D: %1 = add nsw i32 %0, 1; | V: TOP (should be BOTTOM)
D: %2 = add nsw i32 %1, 1; | V: TOP (should be BOTTOM)
If a taint seed is a argument of one function, it will be attached to the entry instructon of that function. The following is the code of taint seeds initialization.
std::map<const llvm::Instruction *, std::set<const llvm::Value *>>
LLVMTaintConfig::makeInitialSeedsImpl() const {
std::map<const llvm::Instruction *, std::set<const llvm::Value *>>
InitialSeeds;
for (const auto *SourceValue : SourceValues) {
if (const auto *Inst = llvm::dyn_cast<llvm::Instruction>(SourceValue)) {
InitialSeeds[Inst].insert(Inst);
} else if (const auto *Arg = llvm::dyn_cast<llvm::Argument>(SourceValue);
Arg && !Arg->getParent()->isDeclaration()) {
const auto *FunFirstInst = &Arg->getParent()->getEntryBlock().front();
InitialSeeds[FunFirstInst].insert(Arg);
}
}
return InitialSeeds;
}
However, when the exploed spuer graph is construted and comes to the DFA Phase II, in the valueComputationTask,
void valueComputationTask(const std::vector<n_t> &Values) {
PAMM_GET_INSTANCE;
for (n_t n : Values) {
for (n_t SP : ICF->getStartPointsOf(ICF->getFunctionOf(n))) {
using TableCell = typename Table<d_t, d_t, EdgeFunctionPtrType>::Cell;
Table<d_t, d_t, EdgeFunctionPtrType> &LookupByTarget =
JumpFn->lookupByTarget(n);
for (const TableCell &SourceValTargetValAndFunction :
LookupByTarget.cellSet()) {
d_t dPrime = SourceValTargetValAndFunction.getRowKey();
d_t d = SourceValTargetValAndFunction.getColumnKey();
EdgeFunctionPtrType fPrime = SourceValTargetValAndFunction.getValue();
l_t TargetVal = val(SP, dPrime);
PHASAR_LOG_LEVEL(DEBUG,"SP " << IDEProblem.NtoString(SP)<<" dprime: " <<IDEProblem.DtoString(dPrime) <<" n: " << IDEProblem.NtoString(n) << fPrime->str() <<" Target val: " << IDEProblem.LtoString(TargetVal));
setVal(n, d,
IDEProblem.join(val(n, d),
fPrime->computeTarget(std::move(TargetVal))));
INC_COUNTER("Value Computation", 1, PAMM_SEVERITY_LEVEL::Full);
}
}
}
}
The lmplementation of getStartPointsOf in for (n_t SP : ICF->getStartPointsOf(ICF->getFunctionOf(n))) is:
std::set<const llvm::Instruction *>
LLVMBasedCFG::getStartPointsOf(const llvm::Function *Fun) const {
if (!Fun) {
return {};
}
if (!Fun->isDeclaration()) {
const auto *EntryInst = &Fun->front().front();
if (IgnoreDbgInstructions && llvm::isa<llvm::DbgInfoIntrinsic>(EntryInst)) {
return {EntryInst->getNextNonDebugInstruction(
false /*Only debug instructions*/)};
}
return {EntryInst};
}
PHASAR_LOG_LEVEL(DEBUG, "Could not get starting points of '"
<< Fun->getName()
<< "' because it is a declaration");
return {};
}
This funciton will return the first no debug entry instruciton.
Which mean, when a taint seed is the parament of a function and the entry instructon of that function is a debug instruction, the result table will record it as bottom however the valueComputationTask will calculate from the first no debug instruction. Will casue the problem illustrate in the beginning.