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-rw-r--r--compilerplugins/clang/unusedindex.cxx87
1 files changed, 87 insertions, 0 deletions
diff --git a/compilerplugins/clang/unusedindex.cxx b/compilerplugins/clang/unusedindex.cxx
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+++ b/compilerplugins/clang/unusedindex.cxx
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+
+/* -*- 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", loopVarDecl->getBeginLoc())
+ << 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: */