106 lines · cpp
1//===----------------------------------------------------------------------===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8 9#include "RedundantPreprocessorCheck.h"10#include "clang/Frontend/CompilerInstance.h"11#include "clang/Lex/Lexer.h"12#include "clang/Lex/PPCallbacks.h"13#include "clang/Lex/Preprocessor.h"14 15namespace clang::tidy::readability {16 17namespace {18/// Information about an opening preprocessor directive.19struct PreprocessorEntry {20 SourceLocation Loc;21 /// Condition used after the preprocessor directive.22 std::string Condition;23};24 25const char WarningDescription[] =26 "nested redundant %select{#if|#ifdef|#ifndef}0; consider removing it";27const char NoteDescription[] = "previous %select{#if|#ifdef|#ifndef}0 was here";28 29class RedundantPreprocessorCallbacks : public PPCallbacks {30 enum DirectiveKind { DK_If = 0, DK_Ifdef = 1, DK_Ifndef = 2 };31 32public:33 explicit RedundantPreprocessorCallbacks(ClangTidyCheck &Check,34 Preprocessor &PP)35 : Check(Check), PP(PP) {}36 37 void If(SourceLocation Loc, SourceRange ConditionRange,38 ConditionValueKind ConditionValue) override {39 const StringRef Condition =40 Lexer::getSourceText(CharSourceRange::getTokenRange(ConditionRange),41 PP.getSourceManager(), PP.getLangOpts());42 checkMacroRedundancy(Loc, Condition, IfStack, DK_If, DK_If, true);43 }44 45 void Ifdef(SourceLocation Loc, const Token &MacroNameTok,46 const MacroDefinition &MacroDefinition) override {47 const std::string MacroName = PP.getSpelling(MacroNameTok);48 checkMacroRedundancy(Loc, MacroName, IfdefStack, DK_Ifdef, DK_Ifdef, true);49 checkMacroRedundancy(Loc, MacroName, IfndefStack, DK_Ifdef, DK_Ifndef,50 false);51 }52 53 void Ifndef(SourceLocation Loc, const Token &MacroNameTok,54 const MacroDefinition &MacroDefinition) override {55 const std::string MacroName = PP.getSpelling(MacroNameTok);56 checkMacroRedundancy(Loc, MacroName, IfndefStack, DK_Ifndef, DK_Ifndef,57 true);58 checkMacroRedundancy(Loc, MacroName, IfdefStack, DK_Ifndef, DK_Ifdef,59 false);60 }61 62 void Endif(SourceLocation Loc, SourceLocation IfLoc) override {63 if (!IfStack.empty() && IfLoc == IfStack.back().Loc)64 IfStack.pop_back();65 if (!IfdefStack.empty() && IfLoc == IfdefStack.back().Loc)66 IfdefStack.pop_back();67 if (!IfndefStack.empty() && IfLoc == IfndefStack.back().Loc)68 IfndefStack.pop_back();69 }70 71private:72 void checkMacroRedundancy(SourceLocation Loc, StringRef MacroName,73 SmallVector<PreprocessorEntry, 4> &Stack,74 DirectiveKind WarningKind, DirectiveKind NoteKind,75 bool Store) {76 if (PP.getSourceManager().isInMainFile(Loc)) {77 for (const auto &Entry : Stack) {78 if (Entry.Condition == MacroName) {79 Check.diag(Loc, WarningDescription) << WarningKind;80 Check.diag(Entry.Loc, NoteDescription, DiagnosticIDs::Note)81 << NoteKind;82 }83 }84 }85 86 if (Store)87 // This is an actual directive to be remembered.88 Stack.push_back({Loc, std::string(MacroName)});89 }90 91 ClangTidyCheck &Check;92 Preprocessor &PP;93 SmallVector<PreprocessorEntry, 4> IfStack;94 SmallVector<PreprocessorEntry, 4> IfdefStack;95 SmallVector<PreprocessorEntry, 4> IfndefStack;96};97} // namespace98 99void RedundantPreprocessorCheck::registerPPCallbacks(100 const SourceManager &SM, Preprocessor *PP, Preprocessor *ModuleExpanderPP) {101 PP->addPPCallbacks(102 ::std::make_unique<RedundantPreprocessorCallbacks>(*this, *PP));103}104 105} // namespace clang::tidy::readability106