87 lines
2.4 KiB
C++
87 lines
2.4 KiB
C++
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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
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/*
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* This file is part of the LibreOffice project.
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*
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/.
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*/
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#include <string>
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#include <iostream>
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#include <unordered_set>
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#include "plugin.hxx"
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#include "check.hxx"
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#include "clang/AST/CXXInheritance.h"
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#include "clang/AST/StmtVisitor.h"
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/*
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Mike Kaganski found a bug where the code was looping over a block and
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not using the index var, and the loop was unnecessary.
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So he wanted to have a look for other places like that.
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*/
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namespace
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{
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class UnusedIndex : public RecursiveASTVisitor<UnusedIndex>, public loplugin::Plugin
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{
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public:
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explicit UnusedIndex(loplugin::InstantiationData const& data)
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: Plugin(data)
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{
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}
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virtual void run() override { TraverseDecl(compiler.getASTContext().getTranslationUnitDecl()); }
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bool TraverseForStmt(ForStmt* stmt);
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bool VisitDeclRefExpr(DeclRefExpr const* stmt);
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private:
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VarDecl const* mLoopVarDecl = nullptr;
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std::unordered_set<VarDecl const*> mFoundSet;
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};
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bool UnusedIndex::TraverseForStmt(ForStmt* stmt)
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{
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if (ignoreLocation(stmt))
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return true;
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auto savedCopy = mLoopVarDecl;
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mLoopVarDecl = nullptr;
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if (stmt->getInit())
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{
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auto declStmt = dyn_cast<DeclStmt>(stmt->getInit());
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if (declStmt && declStmt->isSingleDecl())
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{
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auto varDecl = dyn_cast<VarDecl>(declStmt->getSingleDecl());
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if (varDecl)
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mLoopVarDecl = varDecl;
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}
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}
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// deliberately ignore the other parts of the for stmt, except for the body
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auto ret = RecursiveASTVisitor::TraverseStmt(stmt->getBody());
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if (mLoopVarDecl && mFoundSet.erase(mLoopVarDecl) == 0)
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report(DiagnosticsEngine::Warning, "loop variable not used", mLoopVarDecl->getLocStart())
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<< mLoopVarDecl->getSourceRange();
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mLoopVarDecl = savedCopy;
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return ret;
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}
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bool UnusedIndex::VisitDeclRefExpr(DeclRefExpr const* stmt)
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{
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auto varDecl = dyn_cast<VarDecl>(stmt->getDecl());
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if (!varDecl)
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return true;
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if (mLoopVarDecl && mLoopVarDecl == varDecl)
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mFoundSet.insert(varDecl);
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return true;
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}
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loplugin::Plugin::Registration<UnusedIndex> X("unusedindex", false);
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}
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/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
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