diff options
Diffstat (limited to 'compilerplugins/clang/unusedindex.cxx')
-rw-r--r-- | compilerplugins/clang/unusedindex.cxx | 88 |
1 files changed, 88 insertions, 0 deletions
diff --git a/compilerplugins/clang/unusedindex.cxx b/compilerplugins/clang/unusedindex.cxx new file mode 100644 index 000000000..a47d55b0f --- /dev/null +++ b/compilerplugins/clang/unusedindex.cxx @@ -0,0 +1,88 @@ + +/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */ +/* + * This file is part of the LibreOffice project. + * + * This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. + */ + +#include <string> +#include <iostream> +#include <unordered_set> + +#include "plugin.hxx" +#include "check.hxx" +#include "clang/AST/CXXInheritance.h" +#include "clang/AST/StmtVisitor.h" + +/* + Mike Kaganski found a bug where the code was looping over a block and + not using the index var, and the loop was unnecessary. + So he wanted to have a look for other places like that. +*/ +namespace +{ +class UnusedIndex : public loplugin::FilteringPlugin<UnusedIndex> +{ +public: + explicit UnusedIndex(loplugin::InstantiationData const& data) + : FilteringPlugin(data) + { + } + + virtual void run() override { TraverseDecl(compiler.getASTContext().getTranslationUnitDecl()); } + + bool TraverseForStmt(ForStmt* stmt); + bool VisitDeclRefExpr(DeclRefExpr const* stmt); + +private: + std::vector<VarDecl const*> mLoopVarDecls; + std::unordered_set<VarDecl const*> mFoundSet; +}; + +bool UnusedIndex::TraverseForStmt(ForStmt* stmt) +{ + if (ignoreLocation(stmt)) + return true; + + VarDecl const* loopVarDecl = nullptr; + if (stmt->getInit()) + { + auto declStmt = dyn_cast<DeclStmt>(stmt->getInit()); + if (declStmt && declStmt->isSingleDecl()) + { + loopVarDecl = dyn_cast<VarDecl>(declStmt->getSingleDecl()); + } + } + if (loopVarDecl) + mLoopVarDecls.push_back(loopVarDecl); + + // deliberately ignore the other parts of the for stmt, except for the body + auto ret = RecursiveASTVisitor::TraverseStmt(stmt->getBody()); + + if (loopVarDecl && mFoundSet.erase(loopVarDecl) == 0) + report(DiagnosticsEngine::Warning, "loop variable not used", + compat::getBeginLoc(loopVarDecl)) + << loopVarDecl->getSourceRange(); + + if (loopVarDecl) + mLoopVarDecls.pop_back(); + return ret; +} + +bool UnusedIndex::VisitDeclRefExpr(DeclRefExpr const* stmt) +{ + auto varDecl = dyn_cast<VarDecl>(stmt->getDecl()); + if (!varDecl) + return true; + if (std::find(mLoopVarDecls.begin(), mLoopVarDecls.end(), varDecl) != mLoopVarDecls.end()) + mFoundSet.insert(varDecl); + return true; +} + +loplugin::Plugin::Registration<UnusedIndex> X("unusedindex", false); +} + +/* vim:set shiftwidth=4 softtabstop=4 expandtab: */ |