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[clang-tidy] Speed up deduplicating warnings from alias checks #174237

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Merged
localspook merged 2 commits into from
Jan 4, 2026
Merged

[clang-tidy] Speed up deduplicating warnings from alias checks #174237

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[clang-tidy] Speed up deduplicating warnings from alias checks
localspook Jan 2, 2026
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localspook Jan 3, 2026
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58 changes: 27 additions & 31 deletions clang-tools-extra/clang-tidy/ClangTidyDiagnosticConsumer.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -683,8 +683,6 @@ void ClangTidyDiagnosticConsumer::removeIncompatibleErrors() {
std::tuple<unsigned, EventType, int, int, unsigned> Priority;
};

removeDuplicatedDiagnosticsOfAliasCheckers();

// Compute error sizes.
std::vector<int> Sizes;
std::vector<
Expand Down Expand Up @@ -760,9 +758,12 @@ struct LessClangTidyError {
const tooling::DiagnosticMessage &M1 = LHS.Message;
const tooling::DiagnosticMessage &M2 = RHS.Message;

return std::tie(M1.FilePath, M1.FileOffset, LHS.DiagnosticName,
M1.Message) <
std::tie(M2.FilePath, M2.FileOffset, RHS.DiagnosticName, M2.Message);
// Having DiagnosticName (i.e. the check name) last means sorting
// using this predicate puts duplicate diagnostics into consecutive runs, a
// property which removeDuplicatedDiagnosticsOfAliasCheckers() relies on.
return std::tie(M1.FilePath, M1.FileOffset, M1.Message,
LHS.DiagnosticName) <
std::tie(M2.FilePath, M2.FileOffset, M2.Message, RHS.DiagnosticName);
}
};
struct EqualClangTidyError {
Expand All @@ -778,43 +779,38 @@ std::vector<ClangTidyError> ClangTidyDiagnosticConsumer::take() {

llvm::stable_sort(Errors, LessClangTidyError());
Errors.erase(llvm::unique(Errors, EqualClangTidyError()), Errors.end());
if (RemoveIncompatibleErrors)
if (RemoveIncompatibleErrors) {
removeDuplicatedDiagnosticsOfAliasCheckers();
removeIncompatibleErrors();
}
return std::move(Errors);
}

namespace {
struct LessClangTidyErrorWithoutDiagnosticName {
bool operator()(const ClangTidyError *LHS, const ClangTidyError *RHS) const {
const tooling::DiagnosticMessage &M1 = LHS->Message;
const tooling::DiagnosticMessage &M2 = RHS->Message;

return std::tie(M1.FilePath, M1.FileOffset, M1.Message) <
std::tie(M2.FilePath, M2.FileOffset, M2.Message);
}
};
} // end anonymous namespace

void ClangTidyDiagnosticConsumer::removeDuplicatedDiagnosticsOfAliasCheckers() {
using UniqueErrorSet =
std::set<ClangTidyError *, LessClangTidyErrorWithoutDiagnosticName>;
UniqueErrorSet UniqueErrors;
if (Errors.size() <= 1)
return;

auto IT = Errors.begin();
while (IT != Errors.end()) {
ClangTidyError &Error = *IT;
const std::pair<UniqueErrorSet::iterator, bool> Inserted =
UniqueErrors.insert(&Error);
static constexpr auto AreDuplicates = [](const ClangTidyError &E1,
const ClangTidyError &E2) {
const tooling::DiagnosticMessage &M1 = E1.Message;
const tooling::DiagnosticMessage &M2 = E2.Message;
return std::tie(M1.FilePath, M1.FileOffset, M1.Message) ==
std::tie(M2.FilePath, M2.FileOffset, M2.Message);
};

auto LastUniqueErrorIt = Errors.begin();
for (ClangTidyError &Error : llvm::drop_begin(Errors, 1)) {
ClangTidyError &ExistingError = *LastUniqueErrorIt;
// Unique error, we keep it and move along.
if (Inserted.second) {
++IT;
if (!AreDuplicates(Error, ExistingError)) {
++LastUniqueErrorIt;
if (&*LastUniqueErrorIt != &Error) // Avoid self-moves.
*LastUniqueErrorIt = std::move(Error);
} else {
ClangTidyError &ExistingError = **Inserted.first;
const llvm::StringMap<tooling::Replacements> &CandidateFix =
Error.Message.Fix;
const llvm::StringMap<tooling::Replacements> &ExistingFix =
(*Inserted.first)->Message.Fix;
ExistingError.Message.Fix;

if (CandidateFix != ExistingFix) {
// In case of a conflict, don't suggest any fix-it.
Expand All @@ -833,7 +829,7 @@ void ClangTidyDiagnosticConsumer::removeDuplicatedDiagnosticsOfAliasCheckers() {

// Since it is the same error, we should take it as alias and remove it.
ExistingError.EnabledDiagnosticAliases.emplace_back(Error.DiagnosticName);
IT = Errors.erase(IT);
}
}
Errors.erase(std::next(LastUniqueErrorIt), Errors.end());
}