================ @@ -0,0 +1,182 @@ +//===--- TaggedUnionMemberCountCheck.cpp - clang-tidy ---------------------===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// + +#include "TaggedUnionMemberCountCheck.h" +#include "../utils/OptionsUtils.h" +#include "clang/ASTMatchers/ASTMatchFinder.h" +#include "llvm/ADT/STLExtras.h" +#include "llvm/ADT/SmallSet.h" + +using namespace clang::ast_matchers; + +namespace clang::tidy::bugprone { + +TaggedUnionMemberCountCheck::TaggedUnionMemberCountCheck( + StringRef Name, ClangTidyContext *Context) + : ClangTidyCheck(Name, Context), + StrictModeIsEnabled(Options.get(StrictModeIsEnabledOptionName, true)), + CountingEnumHeuristicIsEnabled( + Options.get(CountingEnumHeuristicIsEnabledOptionName, true)), + RawCountingEnumPrefixes(Options.get(CountingEnumPrefixesOptionName, "")), + RawCountingEnumSuffixes( + Options.get(CountingEnumSuffixesOptionName, "count")), + ParsedCountingEnumPrefixes( + utils::options::parseStringList(RawCountingEnumPrefixes)), + ParsedCountingEnumSuffixes( + utils::options::parseStringList(RawCountingEnumSuffixes)) {} + +void TaggedUnionMemberCountCheck::storeOptions( + ClangTidyOptions::OptionMap &Opts) { + Options.store(Opts, StrictModeIsEnabledOptionName, StrictModeIsEnabled); + Options.store(Opts, CountingEnumHeuristicIsEnabledOptionName, + CountingEnumHeuristicIsEnabled); + Options.store(Opts, CountingEnumPrefixesOptionName, RawCountingEnumPrefixes); + Options.store(Opts, CountingEnumSuffixesOptionName, RawCountingEnumSuffixes); +} + +void TaggedUnionMemberCountCheck::registerMatchers(MatchFinder *Finder) { + Finder->addMatcher( + recordDecl( + allOf(anyOf(isStruct(), isClass()), + has(fieldDecl(hasType(qualType(hasCanonicalType(recordType())))) + .bind("union")), + has(fieldDecl(hasType(qualType(hasCanonicalType(enumType())))) + .bind("tags")))) + .bind("root"), + this); +} + +static bool isUnion(const FieldDecl *R) { + return R->getType().getCanonicalType().getTypePtr()->isUnionType(); +} + +static bool isEnum(const FieldDecl *R) { + return R->getType().getCanonicalType().getTypePtr()->isEnumeralType(); +} + +static bool hasMultipleUnionsOrEnums(const RecordDecl *Rec) { + return llvm::count_if(Rec->fields(), isUnion) > 1 || + llvm::count_if(Rec->fields(), isEnum) > 1; +} + +static bool signEquals(const llvm::APSInt &A, const llvm::APSInt &B) { + return (A.isNegative() && B.isNegative()) || + (A.isStrictlyPositive() && B.isStrictlyPositive()) || + (A.isZero() && B.isZero()); +} + +static bool greaterBySign(const llvm::APSInt &A, const llvm::APSInt &B) { + return (A.isNonNegative() && B.isNegative()) || + (A.isStrictlyPositive() && B.isNonPositive()); +} + +bool TaggedUnionMemberCountCheck::isCountingEnumLikeName( + StringRef Name) const noexcept { + if (llvm::any_of(ParsedCountingEnumPrefixes, + [&Name](const StringRef &prefix) -> bool { + return Name.starts_with_insensitive(prefix); + })) + return true; + if (llvm::any_of(ParsedCountingEnumSuffixes, + [&Name](const StringRef &suffix) -> bool { + return Name.ends_with_insensitive(suffix); + })) + return true; + return false; +} + +size_t TaggedUnionMemberCountCheck::getNumberOfValidEnumValues( + const EnumDecl *Ed) const noexcept { + bool FoundMax = false; + llvm::APSInt MaxTagValue; + llvm::SmallSet<llvm::APSInt, 32> EnumValues; + + // Heuristic for counter enum constants. + // + // enum tag_with_counter { + // tag1, + // tag2, + // tag_count, <-- Searching for these enum constants + // }; + // + // The final tag count is decreased by 1 if and only if: + // 1. There is only one counting enum constant, + // 2. The counting enum constant is the last enum constant that is defined, + // 3. The value of the counting enum constant is the largest out of every enum + // constant. + // The 'ce' prefix is a shorthand for 'counting enum'. + size_t CeCount = 0; + bool IsLast = false; + llvm::APSInt CeValue = llvm::APSInt::get(0); + + for (const auto &&[index, enumerator] : llvm::enumerate(Ed->enumerators())) { + const llvm::APSInt Val = enumerator->getInitVal(); + EnumValues.insert(Val); + if (FoundMax) { + if (greaterBySign(Val, MaxTagValue) || + (signEquals(Val, MaxTagValue) && Val > MaxTagValue)) { + MaxTagValue = Val; + } + } else { + MaxTagValue = Val; + FoundMax = true; + } + + if (CountingEnumHeuristicIsEnabled) { + if (isCountingEnumLikeName(enumerator->getName())) { + IsLast = true; + CeValue = Val; + CeCount += 1; + } else { + IsLast = false; + } + } + } + + size_t ValidValuesCount = EnumValues.size(); + if (CeCount == 1 && IsLast && CeValue == MaxTagValue) { + ValidValuesCount -= 1; + } + + return ValidValuesCount; +} + +void TaggedUnionMemberCountCheck::check( + const MatchFinder::MatchResult &Result) { + const auto *Root = Result.Nodes.getNodeAs<RecordDecl>("root"); + const auto *UnionField = Result.Nodes.getNodeAs<FieldDecl>("union"); + const auto *TagField = Result.Nodes.getNodeAs<FieldDecl>("tags"); + + // The matcher can only narrow down the type to recordType() + if (!isUnion(UnionField)) + return; + + if (hasMultipleUnionsOrEnums(Root)) + return; ---------------- Szelethus wrote:
I'm not sure how can they be of benefit. We already have `isUnion` for TagDecls. https://github.com/llvm/llvm-project/pull/89925 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
