Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

[clang][ubsan] Switch UBSAN optimization to llvm.allow.{runtime,ubsan}.check() #84858

Merged
merged 1 commit into from
Apr 5, 2024
Merged

[clang][ubsan] Switch UBSAN optimization to llvm.allow.{runtime,ubsan}.check() #84858

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Jump to
Jump to file
Failed to load files.
Diff view
Diff view
37 changes: 0 additions & 37 deletions clang/test/CodeGen/remote-traps.c
View file
Open in desktop

This file was deleted.

27 changes: 17 additions & 10 deletions llvm/lib/Transforms/Instrumentation/RemoveTrapsPass.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -11,6 +11,7 @@
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/ProfileSummaryInfo.h"
#include "llvm/IR/Constant.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/Intrinsics.h"
Expand All @@ -35,9 +36,11 @@ STATISTIC(NumChecksRemoved, "Number of removed checks");

static bool removeUbsanTraps(Function &F, const BlockFrequencyInfo &BFI,
const ProfileSummaryInfo *PSI) {
SmallVector<IntrinsicInst *, 16> Remove;
SmallVector<std::pair<IntrinsicInst *, bool>, 16> ReplaceWithValue;
std::unique_ptr<RandomNumberGenerator> Rng;

// TODO:
// https://github.com/llvm/llvm-project/pull/84858#discussion_r1520603139
auto ShouldRemove = [&](bool IsHot) {
if (!RandomRate.getNumOccurrences())
return IsHot;
Expand All @@ -54,21 +57,23 @@ static bool removeUbsanTraps(Function &F, const BlockFrequencyInfo &BFI,
continue;
auto ID = II->getIntrinsicID();
switch (ID) {
case Intrinsic::ubsantrap: {
case Intrinsic::allow_ubsan_check:
case Intrinsic::allow_runtime_check: {
++NumChecksTotal;

bool IsHot = false;
if (PSI) {
uint64_t Count = 0;
for (const auto *PR : predecessors(&BB))
Count += BFI.getBlockProfileCount(PR).value_or(0);
uint64_t Count = BFI.getBlockProfileCount(&BB).value_or(0);
IsHot = PSI->isHotCountNthPercentile(HotPercentileCutoff, Count);
}

if (ShouldRemove(IsHot)) {
Remove.push_back(II);
bool ToRemove = ShouldRemove(IsHot);
ReplaceWithValue.push_back({
II,
ToRemove,
});
if (ToRemove)
++NumChecksRemoved;
}
break;
}
default:
Expand All @@ -77,10 +82,12 @@ static bool removeUbsanTraps(Function &F, const BlockFrequencyInfo &BFI,
}
}

for (IntrinsicInst *I : Remove)
for (auto [I, V] : ReplaceWithValue) {
I->replaceAllUsesWith(ConstantInt::getBool(I->getType(), !V));
I->eraseFromParent();
}

return !Remove.empty();
return !ReplaceWithValue.empty();
}

PreservedAnalyses RemoveTrapsPass::run(Function &F,
Expand Down