forked from OSchip/llvm-project
115 lines
4.1 KiB
C++
115 lines
4.1 KiB
C++
//===--- UnusedUsingDeclsCheck.cpp - clang-tidy----------------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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#include "UnusedUsingDeclsCheck.h"
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#include "clang/AST/ASTContext.h"
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#include "clang/ASTMatchers/ASTMatchFinder.h"
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#include "clang/Lex/Lexer.h"
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using namespace clang::ast_matchers;
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namespace clang {
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namespace tidy {
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namespace misc {
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void UnusedUsingDeclsCheck::registerMatchers(MatchFinder *Finder) {
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Finder->addMatcher(usingDecl(isExpansionInMainFile()).bind("using"), this);
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auto DeclMatcher = hasDeclaration(namedDecl().bind("used"));
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Finder->addMatcher(loc(recordType(DeclMatcher)), this);
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Finder->addMatcher(loc(templateSpecializationType(DeclMatcher)), this);
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Finder->addMatcher(declRefExpr().bind("used"), this);
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Finder->addMatcher(callExpr(callee(unresolvedLookupExpr().bind("used"))),
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this);
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}
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void UnusedUsingDeclsCheck::check(const MatchFinder::MatchResult &Result) {
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if (const auto *Using = Result.Nodes.getNodeAs<UsingDecl>("using")) {
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// FIXME: Implement the correct behavior for using declarations with more
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// than one shadow.
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if (Using->shadow_size() != 1)
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return;
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const auto *TargetDecl =
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Using->shadow_begin()->getTargetDecl()->getCanonicalDecl();
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// Ignores using-declarations defined in macros.
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if (TargetDecl->getLocation().isMacroID())
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return;
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// Ignores using-declarations defined in class definition.
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if (isa<CXXRecordDecl>(TargetDecl->getDeclContext()))
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return;
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if (!isa<RecordDecl>(TargetDecl) && !isa<ClassTemplateDecl>(TargetDecl) &&
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!isa<FunctionDecl>(TargetDecl) && !isa<VarDecl>(TargetDecl) &&
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!isa<FunctionTemplateDecl>(TargetDecl))
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return;
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FoundDecls[TargetDecl] = Using;
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FoundRanges[TargetDecl] = CharSourceRange::getCharRange(
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Using->getLocStart(),
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Lexer::findLocationAfterToken(
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Using->getLocEnd(), tok::semi, *Result.SourceManager,
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Result.Context->getLangOpts(),
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/*SkipTrailingWhitespaceAndNewLine=*/true));
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return;
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}
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// Mark using declarations as used by setting FoundDecls' value to zero. As
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// the AST is walked in order, usages are only marked after a the
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// corresponding using declaration has been found.
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// FIXME: This currently doesn't look at whether the type reference is
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// actually found with the help of the using declaration.
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if (const auto *Used = Result.Nodes.getNodeAs<NamedDecl>("used")) {
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if (const auto *Specialization =
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dyn_cast<ClassTemplateSpecializationDecl>(Used))
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Used = Specialization->getSpecializedTemplate();
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removeFromFoundDecls(Used);
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return;
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}
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if (const auto *DRE = Result.Nodes.getNodeAs<DeclRefExpr>("used")) {
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if (const auto *FD = dyn_cast<FunctionDecl>(DRE->getDecl())) {
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if (const auto *FDT = FD->getPrimaryTemplate())
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removeFromFoundDecls(FDT);
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else
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removeFromFoundDecls(FD);
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} else if (const auto *VD = dyn_cast<VarDecl>(DRE->getDecl())) {
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removeFromFoundDecls(VD);
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}
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}
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// Check the uninstantiated template function usage.
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if (const auto *ULE = Result.Nodes.getNodeAs<UnresolvedLookupExpr>("used")) {
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for (const NamedDecl* ND : ULE->decls()) {
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if (const auto *USD = dyn_cast<UsingShadowDecl>(ND))
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removeFromFoundDecls(USD->getTargetDecl()->getCanonicalDecl());
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}
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}
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}
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void UnusedUsingDeclsCheck::removeFromFoundDecls(const Decl *D) {
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auto I = FoundDecls.find(D->getCanonicalDecl());
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if (I != FoundDecls.end())
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I->second = nullptr;
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}
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void UnusedUsingDeclsCheck::onEndOfTranslationUnit() {
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for (const auto &FoundDecl : FoundDecls) {
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if (FoundDecl.second == nullptr)
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continue;
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diag(FoundDecl.second->getLocation(), "using decl %0 is unused")
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<< FoundDecl.second
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<< FixItHint::CreateRemoval(FoundRanges[FoundDecl.first]);
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}
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FoundDecls.clear();
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}
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} // namespace misc
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} // namespace tidy
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} // namespace clang
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