180 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 "ConvertMemberFunctionsToStaticCheck.h"10#include "clang/AST/ASTContext.h"11#include "clang/AST/DeclCXX.h"12#include "clang/AST/RecursiveASTVisitor.h"13#include "clang/ASTMatchers/ASTMatchFinder.h"14#include "clang/Basic/SourceLocation.h"15#include "clang/Lex/Lexer.h"16 17using namespace clang::ast_matchers;18 19namespace clang::tidy::readability {20 21namespace {22 23AST_MATCHER(CXXMethodDecl, isStatic) { return Node.isStatic(); }24 25AST_MATCHER(CXXMethodDecl, hasTrivialBody) { return Node.hasTrivialBody(); }26 27AST_MATCHER(CXXMethodDecl, isOverloadedOperator) {28 return Node.isOverloadedOperator();29}30 31AST_MATCHER(CXXRecordDecl, hasAnyDependentBases) {32 return Node.hasAnyDependentBases();33}34 35AST_MATCHER(CXXMethodDecl, isTemplate) {36 return Node.getTemplatedKind() != FunctionDecl::TK_NonTemplate;37}38 39AST_MATCHER(CXXMethodDecl, isDependentContext) {40 return Node.isDependentContext();41}42 43AST_MATCHER(CXXMethodDecl, isInsideMacroDefinition) {44 const ASTContext &Ctxt = Finder->getASTContext();45 return clang::Lexer::makeFileCharRange(46 clang::CharSourceRange::getCharRange(47 Node.getTypeSourceInfo()->getTypeLoc().getSourceRange()),48 Ctxt.getSourceManager(), Ctxt.getLangOpts())49 .isInvalid();50}51 52AST_MATCHER_P(CXXMethodDecl, hasCanonicalDecl,53 ast_matchers::internal::Matcher<CXXMethodDecl>, InnerMatcher) {54 return InnerMatcher.matches(*Node.getCanonicalDecl(), Finder, Builder);55}56 57AST_MATCHER(CXXMethodDecl, usesThis) {58 class FindUsageOfThis : public RecursiveASTVisitor<FindUsageOfThis> {59 public:60 bool Used = false;61 62 bool VisitCXXThisExpr(const CXXThisExpr *E) {63 Used = true;64 return false; // Stop traversal.65 }66 67 // If we enter a class declaration, don't traverse into it as any usages of68 // `this` will correspond to the nested class.69 bool TraverseCXXRecordDecl(CXXRecordDecl *RD) { return true; }70 71 } UsageOfThis;72 73 // TraverseStmt does not modify its argument.74 UsageOfThis.TraverseStmt(Node.getBody());75 76 return UsageOfThis.Used;77}78 79} // namespace80 81void ConvertMemberFunctionsToStaticCheck::registerMatchers(82 MatchFinder *Finder) {83 Finder->addMatcher(84 cxxMethodDecl(85 isDefinition(), isUserProvided(),86 unless(anyOf(87 isExpansionInSystemHeader(), isVirtual(), isStatic(),88 hasTrivialBody(), isOverloadedOperator(), cxxConstructorDecl(),89 cxxDestructorDecl(), cxxConversionDecl(),90 isExplicitObjectMemberFunction(), isTemplate(),91 isDependentContext(),92 ofClass(anyOf(93 isLambda(),94 hasAnyDependentBases()) // Method might become virtual95 // depending on template base class.96 ),97 isInsideMacroDefinition(),98 hasCanonicalDecl(isInsideMacroDefinition()), usesThis())))99 .bind("x"),100 this);101}102 103/// Obtain the original source code text from a SourceRange.104static StringRef getStringFromRange(SourceManager &SourceMgr,105 const LangOptions &LangOpts,106 SourceRange Range) {107 if (SourceMgr.getFileID(Range.getBegin()) !=108 SourceMgr.getFileID(Range.getEnd()))109 return {};110 111 return Lexer::getSourceText(CharSourceRange(Range, true), SourceMgr,112 LangOpts);113}114 115static SourceRange getLocationOfConst(const TypeSourceInfo *TSI,116 SourceManager &SourceMgr,117 const LangOptions &LangOpts) {118 assert(TSI);119 const auto FTL = TSI->getTypeLoc().IgnoreParens().getAs<FunctionTypeLoc>();120 assert(FTL);121 122 const SourceRange Range{FTL.getRParenLoc().getLocWithOffset(1),123 FTL.getLocalRangeEnd()};124 // Inside Range, there might be other keywords and trailing return types.125 // Find the exact position of "const".126 const StringRef Text = getStringFromRange(SourceMgr, LangOpts, Range);127 const size_t Offset = Text.find("const");128 if (Offset == StringRef::npos)129 return {};130 131 const SourceLocation Start = Range.getBegin().getLocWithOffset(Offset);132 return {Start, Start.getLocWithOffset(strlen("const") - 1)};133}134 135void ConvertMemberFunctionsToStaticCheck::check(136 const MatchFinder::MatchResult &Result) {137 const auto *Definition = Result.Nodes.getNodeAs<CXXMethodDecl>("x");138 139 // TODO: For out-of-line declarations, don't modify the source if the header140 // is excluded by the -header-filter option.141 const DiagnosticBuilder Diag =142 diag(Definition->getLocation(), "method %0 can be made static")143 << Definition;144 145 // TODO: Would need to remove those in a fix-it.146 if (Definition->getMethodQualifiers().hasVolatile() ||147 Definition->getMethodQualifiers().hasRestrict() ||148 Definition->getRefQualifier() != RQ_None)149 return;150 151 const CXXMethodDecl *Declaration = Definition->getCanonicalDecl();152 153 if (Definition->isConst()) {154 // Make sure that we either remove 'const' on both declaration and155 // definition or emit no fix-it at all.156 const SourceRange DefConst = getLocationOfConst(157 Definition->getTypeSourceInfo(), *Result.SourceManager,158 Result.Context->getLangOpts());159 160 if (DefConst.isInvalid())161 return;162 163 if (Declaration != Definition) {164 const SourceRange DeclConst = getLocationOfConst(165 Declaration->getTypeSourceInfo(), *Result.SourceManager,166 Result.Context->getLangOpts());167 168 if (DeclConst.isInvalid())169 return;170 Diag << FixItHint::CreateRemoval(DeclConst);171 }172 173 // Remove existing 'const' from both declaration and definition.174 Diag << FixItHint::CreateRemoval(DefConst);175 }176 Diag << FixItHint::CreateInsertion(Declaration->getBeginLoc(), "static ");177}178 179} // namespace clang::tidy::readability180