// Tries to remove a sanity check; returns true if it worked.
bool AsapPass::optimizeCheckAway(llvm::Instruction *Inst) {
BranchInst *BI = cast<BranchInst>(Inst);
assert(BI->isConditional() && "Sanity check must be conditional branch.");
unsigned int RegularBranch = getRegularBranch(BI, SCI);
bool Changed = false;
if (RegularBranch == 0) {
BI->setCondition(ConstantInt::getTrue(Inst->getContext()));
Changed = true;
} else if (RegularBranch == 1) {
BI->setCondition(ConstantInt::getFalse(Inst->getContext()));
Changed = true;
} else {
// This can happen, e.g., in the following case:
// array[-1] = a + b;
// is transformed into
// if (a + b overflows)
// report_overflow()
// else
// report_index_out_of_bounds();
// In this case, removing the sanity check does not help much, so we
// just do nothing.
// Thanks to Will Dietz for his explanation at
// http://lists.cs.uiuc.edu/pipermail/llvmdev/2014-April/071958.html
dbgs() << "Warning: Sanity check with no regular branch found.\n";
dbgs() << "The sanity check has been kept intact.\n";
}
if (PrintRemovedChecks && Changed) {
DebugLoc DL = getSanityCheckDebugLoc(BI, RegularBranch);
printDebugLoc(DL, BI->getContext(), dbgs());
dbgs() << ": SanityCheck with cost ";
dbgs() << *BI->getMetadata("cost")->getOperand(0);
if (MDNode *IA = DL.getInlinedAt()) {
dbgs() << " (inlined at ";
printDebugLoc(DebugLoc(IA), BI->getContext(), dbgs());
dbgs() << ")";
}
BasicBlock *Succ = BI->getSuccessor(RegularBranch == 0 ? 1 : 0);
if (const CallInst *CI = SCI->findSanityCheckCall(Succ)) {
dbgs() << " " << CI->getCalledFunction()->getName();
}
dbgs() << "\n";
}
return Changed;
}
void Executor::executeBranch(Instruction *i, bool cond) {
assert(i && "Expecting an instruction!");
LastExecutedBB = i->getParent();
if (CollectBlockTraces) {
ExecutedBlocks.push_back(LastExecutedBB);
}
BranchInst *br = dyn_cast<BranchInst>(i);
if (br->isConditional()) {
// Loops: check if the control-flow
// jump back to a loop header.
std::string bbname = PathLoopInfo->getLoopLatchName(br);
BasicBlock *nextBB1 = br->getSuccessor(0);
BasicBlock *nextBB2 = br->getSuccessor(1);
if ((cond && bbname==nextBB1->getName().str())
|| (!cond && bbname==nextBB2->getName().str())) {
unsigned line = 0;
if (MDNode *N = br->getMetadata("dbg")) {
DILocation Loc(N);
line = Loc.getLineNumber();
}
//std::cout << "Current: " << LastExecutedBB->getName().str() << std::endl;
//std::cout << "LoopLatch: " << bbname << std::endl;
std::cout << "Violated property: unwinding assertion";
std::cout << " (line " << line << ")\n";
//exit(1);
DisabledSymbolicExeCurRun = true;
return;
}
// Next block to be executed
if (cond) {
NextBB = nextBB1;
} else {
NextBB = nextBB2;
}
} else {
// Next block to be executed
NextBB = br->getSuccessor(0);
}
if (!DisabledSymbolicExeCurRun) {
PathContext->propagatePointers(LastExecutedBB, NextBB);
}
// For program coverage analysis
//Profile->covered(br, cond);
//Profile->covered(br->getParent());
if(br->isConditional()) {
// Update the number of time we jump in the IR
GotoCount++;
if (GotoCount>MaxDepth) {
std::cout << "warning: maximum goto-count (";
std::cout << GotoCount << ") reached.\n";
DisabledSymbolicExeCurRun = true;
return;
}
if (DisabledSymbolicExeCurRun) {
return;
}
Value *vcond = br->getCondition();
// vcond in domain(S)
if (SMAP->contains(vcond)) {
SymbolPtr Svcond = SMAP->get(vcond);
// Report(S(vcond), branchTaken)
Path->addBranchCell(Svcond, cond, i);
}
}
}
