[clang-tidy] Add readability-operators-representation check

Check helps enforce consistent token representation for binary, unary and
overloaded operators in C++ code. The check supports both traditional and
alternative representations of operators.

Reviewed By: carlosgalvezp

Differential Revision: https://reviews.llvm.org/D144522

1 files changed, 335 insertions, 0 deletions

diff --git a/clang-tools-extra/clang-tidy/readability/OperatorsRepresentationCheck.cpp b/clang-tools-extra/clang-tidy/readability/OperatorsRepresentationCheck.cpp
new file mode 100644
index 0000000..ab45dab
--- /dev/null
+++ b/clang-tools-extra/clang-tidy/readability/OperatorsRepresentationCheck.cpp
@@ -0,0 +1,335 @@
+//===--- OperatorsRepresentationCheck.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 "OperatorsRepresentationCheck.h"
+#include "../utils/OptionsUtils.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+#include "clang/Lex/Lexer.h"
+#include "llvm/ADT/STLExtras.h"
+#include <array>
+#include <utility>
+
+using namespace clang::ast_matchers;
+
+namespace clang::tidy::readability {
+
+static StringRef getOperatorSpelling(SourceLocation Loc, ASTContext &Context) {
+  if (Loc.isInvalid())
+    return {};
+
+  SourceManager &SM = Context.getSourceManager();
+
+  Loc = SM.getSpellingLoc(Loc);
+  if (Loc.isInvalid())
+    return {};
+
+  const CharSourceRange TokenRange = CharSourceRange::getTokenRange(Loc);
+  return Lexer::getSourceText(TokenRange, SM, Context.getLangOpts());
+}
+
+namespace {
+
+AST_MATCHER_P2(BinaryOperator, hasInvalidBinaryOperatorRepresentation,
+               BinaryOperatorKind, Kind, llvm::StringRef,
+               ExpectedRepresentation) {
+  if (Node.getOpcode() != Kind || ExpectedRepresentation.empty())
+    return false;
+
+  StringRef Spelling =
+      getOperatorSpelling(Node.getOperatorLoc(), Finder->getASTContext());
+  return !Spelling.empty() && Spelling != ExpectedRepresentation;
+}
+
+AST_MATCHER_P2(UnaryOperator, hasInvalidUnaryOperatorRepresentation,
+               UnaryOperatorKind, Kind, llvm::StringRef,
+               ExpectedRepresentation) {
+  if (Node.getOpcode() != Kind || ExpectedRepresentation.empty())
+    return false;
+
+  StringRef Spelling =
+      getOperatorSpelling(Node.getOperatorLoc(), Finder->getASTContext());
+  return !Spelling.empty() && Spelling != ExpectedRepresentation;
+}
+
+AST_MATCHER_P2(CXXOperatorCallExpr, hasInvalidOverloadedOperatorRepresentation,
+               OverloadedOperatorKind, Kind, llvm::StringRef,
+               ExpectedRepresentation) {
+  if (Node.getOperator() != Kind || ExpectedRepresentation.empty())
+    return false;
+
+  StringRef Spelling =
+      getOperatorSpelling(Node.getOperatorLoc(), Finder->getASTContext());
+  return !Spelling.empty() && Spelling != ExpectedRepresentation;
+}
+
+} // namespace
+
+constexpr std::array<std::pair<llvm::StringRef, llvm::StringRef>, 2U>
+    UnaryRepresentation{{{"!", "not"}, {"~", "compl"}}};
+
+constexpr std::array<std::pair<llvm::StringRef, llvm::StringRef>, 9U>
+    OperatorsRepresentation{{{"&&", "and"},
+                             {"||", "or"},
+                             {"^", "xor"},
+                             {"&", "bitand"},
+                             {"|", "bitor"},
+                             {"&=", "and_eq"},
+                             {"|=", "or_eq"},
+                             {"!=", "not_eq"},
+                             {"^=", "xor_eq"}}};
+
+static llvm::StringRef translate(llvm::StringRef Value) {
+  for (const auto &[Traditional, Alternative] : UnaryRepresentation) {
+    if (Value == Traditional)
+      return Alternative;
+    if (Value == Alternative)
+      return Traditional;
+  }
+
+  for (const auto &[Traditional, Alternative] : OperatorsRepresentation) {
+    if (Value == Traditional)
+      return Alternative;
+    if (Value == Alternative)
+      return Traditional;
+  }
+  return {};
+}
+
+static bool isNotOperatorStr(llvm::StringRef Value) {
+  return translate(Value).empty();
+}
+
+static bool isSeparator(char C) noexcept {
+  constexpr llvm::StringRef Separators(" \t\r\n\0()<>{};,");
+  return llvm::is_contained(Separators, C);
+}
+
+static bool needEscaping(llvm::StringRef Operator) {
+  switch (Operator[0]) {
+  case '&':
+  case '|':
+  case '!':
+  case '^':
+  case '~':
+    return false;
+  default:
+    return true;
+  }
+}
+
+static llvm::StringRef
+getRepresentation(const std::vector<llvm::StringRef> &Config,
+                  llvm::StringRef Traditional, llvm::StringRef Alternative) {
+  if (llvm::is_contained(Config, Traditional))
+    return Traditional;
+  if (llvm::is_contained(Config, Alternative))
+    return Alternative;
+  return {};
+}
+
+template <typename T>
+static bool isAnyOperatorEnabled(const std::vector<llvm::StringRef> &Config,
+                                 T &&Operators) {
+  for (const auto &[traditional, alternative] : Operators) {
+    if (!getRepresentation(Config, traditional, alternative).empty())
+      return true;
+  }
+  return false;
+}
+
+OperatorsRepresentationCheck::OperatorsRepresentationCheck(
+    StringRef Name, ClangTidyContext *Context)
+    : ClangTidyCheck(Name, Context),
+      BinaryOperators(
+          utils::options::parseStringList(Options.get("BinaryOperators", ""))),
+      OverloadedOperators(utils::options::parseStringList(
+          Options.get("OverloadedOperators", ""))) {
+  llvm::erase_if(BinaryOperators, isNotOperatorStr);
+  llvm::erase_if(OverloadedOperators, isNotOperatorStr);
+}
+
+void OperatorsRepresentationCheck::storeOptions(
+    ClangTidyOptions::OptionMap &Opts) {
+  Options.store(Opts, "BinaryOperators",
+                utils::options::serializeStringList(BinaryOperators));
+  Options.store(Opts, "OverloadedOperators",
+                utils::options::serializeStringList(OverloadedOperators));
+}
+
+std::optional<TraversalKind>
+OperatorsRepresentationCheck::getCheckTraversalKind() const {
+  return TK_IgnoreUnlessSpelledInSource;
+}
+
+bool OperatorsRepresentationCheck::isLanguageVersionSupported(
+    const LangOptions &LangOpts) const {
+  return LangOpts.CPlusPlus;
+}
+
+void OperatorsRepresentationCheck::registerBinaryOperatorMatcher(
+    MatchFinder *Finder) {
+  if (!isAnyOperatorEnabled(BinaryOperators, OperatorsRepresentation))
+    return;
+
+  Finder->addMatcher(
+      binaryOperator(
+          unless(isExpansionInSystemHeader()),
+          anyOf(hasInvalidBinaryOperatorRepresentation(
+                    BO_LAnd, getRepresentation(BinaryOperators, "&&", "and")),
+                hasInvalidBinaryOperatorRepresentation(
+                    BO_LOr, getRepresentation(BinaryOperators, "||", "or")),
+                hasInvalidBinaryOperatorRepresentation(
+                    BO_NE, getRepresentation(BinaryOperators, "!=", "not_eq")),
+                hasInvalidBinaryOperatorRepresentation(
+                    BO_Xor, getRepresentation(BinaryOperators, "^", "xor")),
+                hasInvalidBinaryOperatorRepresentation(
+                    BO_And, getRepresentation(BinaryOperators, "&", "bitand")),
+                hasInvalidBinaryOperatorRepresentation(
+                    BO_Or, getRepresentation(BinaryOperators, "|", "bitor")),
+                hasInvalidBinaryOperatorRepresentation(
+                    BO_AndAssign,
+                    getRepresentation(BinaryOperators, "&=", "and_eq")),
+                hasInvalidBinaryOperatorRepresentation(
+                    BO_OrAssign,
+                    getRepresentation(BinaryOperators, "|=", "or_eq")),
+                hasInvalidBinaryOperatorRepresentation(
+                    BO_XorAssign,
+                    getRepresentation(BinaryOperators, "^=", "xor_eq"))))
+          .bind("binary_op"),
+      this);
+}
+
+void OperatorsRepresentationCheck::registerUnaryOperatorMatcher(
+    MatchFinder *Finder) {
+  if (!isAnyOperatorEnabled(BinaryOperators, UnaryRepresentation))
+    return;
+
+  Finder->addMatcher(
+      unaryOperator(
+          unless(isExpansionInSystemHeader()),
+          anyOf(hasInvalidUnaryOperatorRepresentation(
+                    UO_LNot, getRepresentation(BinaryOperators, "!", "not")),
+                hasInvalidUnaryOperatorRepresentation(
+                    UO_Not, getRepresentation(BinaryOperators, "~", "compl"))))
+          .bind("unary_op"),
+      this);
+}
+
+void OperatorsRepresentationCheck::registerOverloadedOperatorMatcher(
+    MatchFinder *Finder) {
+  if (!isAnyOperatorEnabled(OverloadedOperators, OperatorsRepresentation) &&
+      !isAnyOperatorEnabled(OverloadedOperators, UnaryRepresentation))
+    return;
+
+  Finder->addMatcher(
+      cxxOperatorCallExpr(
+          unless(isExpansionInSystemHeader()),
+          anyOf(
+              hasInvalidOverloadedOperatorRepresentation(
+                  OO_AmpAmp,
+                  getRepresentation(OverloadedOperators, "&&", "and")),
+              hasInvalidOverloadedOperatorRepresentation(
+                  OO_PipePipe,
+                  getRepresentation(OverloadedOperators, "||", "or")),
+              hasInvalidOverloadedOperatorRepresentation(
+                  OO_Exclaim,
+                  getRepresentation(OverloadedOperators, "!", "not")),
+              hasInvalidOverloadedOperatorRepresentation(
+                  OO_ExclaimEqual,
+                  getRepresentation(OverloadedOperators, "!=", "not_eq")),
+              hasInvalidOverloadedOperatorRepresentation(
+                  OO_Caret, getRepresentation(OverloadedOperators, "^", "xor")),
+              hasInvalidOverloadedOperatorRepresentation(
+                  OO_Amp,
+                  getRepresentation(OverloadedOperators, "&", "bitand")),
+              hasInvalidOverloadedOperatorRepresentation(
+                  OO_Pipe,
+                  getRepresentation(OverloadedOperators, "|", "bitor")),
+              hasInvalidOverloadedOperatorRepresentation(
+                  OO_AmpEqual,
+                  getRepresentation(OverloadedOperators, "&=", "and_eq")),
+              hasInvalidOverloadedOperatorRepresentation(
+                  OO_PipeEqual,
+                  getRepresentation(OverloadedOperators, "|=", "or_eq")),
+              hasInvalidOverloadedOperatorRepresentation(
+                  OO_CaretEqual,
+                  getRepresentation(OverloadedOperators, "^=", "xor_eq")),
+              hasInvalidOverloadedOperatorRepresentation(
+                  OO_Tilde,
+                  getRepresentation(OverloadedOperators, "~", "compl"))))
+          .bind("overloaded_op"),
+      this);
+}
+
+void OperatorsRepresentationCheck::registerMatchers(MatchFinder *Finder) {
+  registerBinaryOperatorMatcher(Finder);
+  registerUnaryOperatorMatcher(Finder);
+  registerOverloadedOperatorMatcher(Finder);
+}
+
+void OperatorsRepresentationCheck::check(
+    const MatchFinder::MatchResult &Result) {
+
+  SourceLocation Loc;
+
+  if (const auto *Op = Result.Nodes.getNodeAs<BinaryOperator>("binary_op"))
+    Loc = Op->getOperatorLoc();
+  else if (const auto *Op = Result.Nodes.getNodeAs<UnaryOperator>("unary_op"))
+    Loc = Op->getOperatorLoc();
+  else if (const auto *Op =
+               Result.Nodes.getNodeAs<CXXOperatorCallExpr>("overloaded_op"))
+    Loc = Op->getOperatorLoc();
+
+  if (Loc.isInvalid())
+    return;
+
+  Loc = Result.SourceManager->getSpellingLoc(Loc);
+  if (Loc.isInvalid() || Loc.isMacroID())
+    return;
+
+  const CharSourceRange TokenRange = CharSourceRange::getTokenRange(Loc);
+  if (TokenRange.isInvalid())
+    return;
+
+  StringRef Spelling = Lexer::getSourceText(TokenRange, *Result.SourceManager,
+                                            Result.Context->getLangOpts());
+  StringRef TranslatedSpelling = translate(Spelling);
+
+  if (TranslatedSpelling.empty())
+    return;
+
+  std::string FixSpelling = TranslatedSpelling.str();
+
+  StringRef SourceRepresentation = "an alternative";
+  StringRef TargetRepresentation = "a traditional";
+  if (needEscaping(TranslatedSpelling)) {
+    SourceRepresentation = "a traditional";
+    TargetRepresentation = "an alternative";
+
+    StringRef SpellingEx = Lexer::getSourceText(
+        CharSourceRange::getCharRange(
+            TokenRange.getBegin().getLocWithOffset(-1),
+            TokenRange.getBegin().getLocWithOffset(Spelling.size() + 1U)),
+        *Result.SourceManager, Result.Context->getLangOpts());
+    if (SpellingEx.empty() || !isSeparator(SpellingEx.front()))
+      FixSpelling.insert(FixSpelling.begin(), ' ');
+    if (SpellingEx.empty() || !isSeparator(SpellingEx.back()))
+      FixSpelling.push_back(' ');
+  }
+
+  diag(
+      Loc,
+      "'%0' is %1 token spelling, consider using %2 token '%3' for consistency")
+      << Spelling << SourceRepresentation << TargetRepresentation
+      << TranslatedSpelling
+      << FixItHint::CreateReplacement(TokenRange, FixSpelling);
+}
+
+} // namespace clang::tidy::readability