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[ubsan] Parse and use <cutoffs[0,1,2]=70000;cutoffs[5,6,8]=90000> in LowerAllowCheckPass #124211

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Merged
merged 11 commits into from
Jan 28, 2025
Merged

[ubsan] Parse and use <cutoffs[0,1,2]=70000;cutoffs[5,6,8]=90000> in LowerAllowCheckPass #124211

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5d1944f
[ubsan] Plumb through -fsanitize-skip-hot-cutoff to LowerAllowCheckPass
thurstond Jan 22, 2025
fca3e2b
Remove clang-related changes (for future patch TBA)
thurstond Jan 27, 2025
0f5593f
Address Vitaly's feedback (options format coming in next commit)
thurstond Jan 27, 2025
7b6b016
Change options format
thurstond Jan 28, 2025
bdb502e
Remove &
thurstond Jan 28, 2025
e183793
clang-format
thurstond Jan 28, 2025
e514a83
Remove unnecessary whitespace change
thurstond Jan 28, 2025
b2050de
Address Vitaly's feedback
thurstond Jan 28, 2025
9593c4e
Address more feedback
thurstond Jan 28, 2025
fe5e30d
Avoid cast
thurstond Jan 28, 2025
dd0685f
Remove BoundsChecking change (moved to
thurstond Jan 28, 2025
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20 changes: 10 additions & 10 deletions llvm/lib/Transforms/Instrumentation/LowerAllowCheckPass.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -73,7 +73,7 @@ static void emitRemark(IntrinsicInst *II, OptimizationRemarkEmitter &ORE,
static bool removeUbsanTraps(Function &F, const BlockFrequencyInfo &BFI,
const ProfileSummaryInfo *PSI,
OptimizationRemarkEmitter &ORE,
std::vector<unsigned int> const &cutoffs) {
const std::vector<unsigned int> &cutoffs) {
SmallVector<std::pair<IntrinsicInst *, bool>, 16> ReplaceWithValue;
std::unique_ptr<RandomNumberGenerator> Rng;

Expand All @@ -84,31 +84,31 @@ static bool removeUbsanTraps(Function &F, const BlockFrequencyInfo &BFI,
};

auto GetCutoff = [&](const IntrinsicInst *II) {
unsigned int cutoff = 0;
if (HotPercentileCutoff.getNumOccurrences())
cutoff = HotPercentileCutoff;
return static_cast<unsigned int>(HotPercentileCutoff);
else if (II->getIntrinsicID() == Intrinsic::allow_ubsan_check) {
auto *Kind = cast<ConstantInt>(II->getArgOperand(0));
if (Kind->getZExtValue() < cutoffs.size())
cutoff = cutoffs[Kind->getZExtValue()];
return cutoffs[Kind->getZExtValue()];
}

return cutoff;
return 0U;
};

auto ShouldRemoveHot = [&](const BasicBlock &BB, unsigned int cutoff) {
return PSI && PSI->isHotCountNthPercentile(
cutoff, BFI.getBlockProfileCount(&BB).value_or(0));
return (cutoff == 1000000) ||
(PSI && PSI->isHotCountNthPercentile(
cutoff, BFI.getBlockProfileCount(&BB).value_or(0)));
};

auto ShouldRemoveRandom = [&]() {
return RandomRate.getNumOccurrences() &&
!std::bernoulli_distribution(RandomRate)(GetRng());
};

auto ShouldRemove = [&](const BasicBlock &BB, const IntrinsicInst *II) {
auto ShouldRemove = [&](const IntrinsicInst *II) {
unsigned int cutoff = GetCutoff(II);
return ShouldRemoveRandom() || ShouldRemoveHot(BB, cutoff);
return ShouldRemoveRandom() || ShouldRemoveHot(*(II->getParent()), cutoff);
};

for (BasicBlock &BB : F) {
Expand All @@ -122,7 +122,7 @@ static bool removeUbsanTraps(Function &F, const BlockFrequencyInfo &BFI,
case Intrinsic::allow_runtime_check: {
++NumChecksTotal;

bool ToRemove = ShouldRemove(BB, II);
bool ToRemove = ShouldRemove(II);

ReplaceWithValue.push_back({
II,
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