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-rw-r--r--compilerplugins/clang/commaoperator.cxx130
1 files changed, 130 insertions, 0 deletions
diff --git a/compilerplugins/clang/commaoperator.cxx b/compilerplugins/clang/commaoperator.cxx
new file mode 100644
index 0000000000..3ba1c89c4b
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+++ b/compilerplugins/clang/commaoperator.cxx
@@ -0,0 +1,130 @@
+/* -*- 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 <cassert>
+#include <string>
+#include <iostream>
+#include <fstream>
+#include <set>
+
+#include "plugin.hxx"
+
+/**
+the comma operator is best used sparingly
+*/
+
+namespace {
+
+Stmt const * lookThroughExprWithCleanups(Stmt const * stmt) {
+ if (auto const e = dyn_cast_or_null<ExprWithCleanups>(stmt)) {
+ return e->getSubExpr();
+ }
+ return stmt;
+}
+
+class CommaOperator:
+ public loplugin::FilteringPlugin<CommaOperator>
+{
+public:
+ explicit CommaOperator(loplugin::InstantiationData const & data):
+ FilteringPlugin(data) {}
+
+ virtual void run() override
+ {
+ TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
+ }
+
+ bool TraverseForStmt(ForStmt * stmt) {
+ auto const saved1 = ignore1_;
+ ignore1_ = lookThroughExprWithCleanups(stmt->getInit());
+ auto const saved2 = ignore2_;
+ ignore2_ = lookThroughExprWithCleanups(stmt->getInc());
+ auto const ret = RecursiveASTVisitor::TraverseForStmt(stmt);
+ ignore1_ = saved1;
+ ignore2_ = saved2;
+ return ret;
+ }
+
+ bool TraverseWhileStmt(WhileStmt * stmt) {
+ auto const saved1 = ignore1_;
+ ignore1_ = lookThroughExprWithCleanups(stmt->getCond());
+ auto const ret = RecursiveASTVisitor::TraverseWhileStmt(stmt);
+ ignore1_ = saved1;
+ return ret;
+ }
+
+ bool TraverseParenExpr(ParenExpr * expr) {
+ auto const saved1 = ignore1_;
+ ignore1_ = expr->getSubExpr();
+ auto const ret = RecursiveASTVisitor::TraverseParenExpr(expr);
+ ignore1_ = saved1;
+ return ret;
+ }
+
+ bool TraverseBinaryOperator(BinaryOperator * expr) {
+ if (expr->getOpcode() != BO_Comma) {
+ return RecursiveASTVisitor::TraverseBinaryOperator(expr);
+ }
+ if (!WalkUpFromBinaryOperator(expr)) {
+ return false;
+ }
+ auto const saved1 = ignore1_;
+ ignore1_ = expr->getLHS();
+ auto const ret = TraverseStmt(expr->getLHS())
+ && TraverseStmt(expr->getRHS());
+ ignore1_ = saved1;
+ return ret;
+ }
+
+ bool VisitBinaryOperator(const BinaryOperator* );
+
+private:
+ Stmt const * ignore1_ = nullptr;
+ Stmt const * ignore2_ = nullptr;
+};
+
+bool CommaOperator::VisitBinaryOperator(const BinaryOperator* binaryOp)
+{
+ if (binaryOp->getOpcode() != BO_Comma) {
+ return true;
+ }
+ if (binaryOp == ignore1_ || binaryOp == ignore2_) {
+ return true;
+ }
+ if (ignoreLocation(binaryOp)) {
+ return true;
+ }
+ // Ignore FD_SET expanding to "...} while(0, 0)" in some Microsoft
+ // winsock2.h (TODO: improve heuristic of determining that the whole
+ // binaryOp is part of a single macro body expansion):
+ if (compiler.getSourceManager().isMacroBodyExpansion(
+ binaryOp->getBeginLoc())
+ && compiler.getSourceManager().isMacroBodyExpansion(
+ binaryOp->getOperatorLoc())
+ && compiler.getSourceManager().isMacroBodyExpansion(
+ binaryOp->getEndLoc())
+ && ignoreLocation(
+ compiler.getSourceManager().getSpellingLoc(
+ binaryOp->getOperatorLoc())))
+ {
+ return true;
+ }
+ report(
+ DiagnosticsEngine::Warning, "comma operator hides code",
+ binaryOp->getOperatorLoc())
+ << binaryOp->getSourceRange();
+ return true;
+}
+
+
+loplugin::Plugin::Registration< CommaOperator > X("commaoperator", true);
+
+}
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */