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Diffstat (limited to 'compilerplugins/clang/empty.cxx')
| -rw-r--r-- | compilerplugins/clang/empty.cxx | 167 |
1 files changed, 167 insertions, 0 deletions
diff --git a/compilerplugins/clang/empty.cxx b/compilerplugins/clang/empty.cxx new file mode 100644 index 000000000..d5129d29d --- /dev/null +++ b/compilerplugins/clang/empty.cxx @@ -0,0 +1,167 @@ +/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4; fill-column: 100 -*- */ +/* + * 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/. + */ + +#ifndef LO_CLANG_SHARED_PLUGINS + +#include <cassert> + +#include "check.hxx" +#include "plugin.hxx" + +// Warn about checks whether a container is empty done via an (expensive) call to obtain the +// container's size. For now only handles cases involving strlen. + +namespace +{ +BinaryOperatorKind reverse(BinaryOperatorKind op) +{ + switch (op) + { + case BO_LT: + return BO_GE; + case BO_GT: + return BO_LE; + case BO_LE: + return BO_GT; + case BO_GE: + return BO_LT; + case BO_EQ: + case BO_NE: + return op; + default: + abort(); + } +} + +class Empty : public loplugin::FilteringPlugin<Empty> +{ +public: + explicit Empty(loplugin::InstantiationData const& data) + : FilteringPlugin(data) + { + } + + bool VisitBinaryOperator(BinaryOperator const* expr) + { + if (expr->isRelationalOp() || expr->isEqualityOp()) + { + visitComparison(expr); + } + return true; + } + +private: + void run() override { TraverseDecl(compiler.getASTContext().getTranslationUnitDecl()); } + + void visitComparison(BinaryOperator const* expr, CallExpr const* lhs, Expr const* rhs, + BinaryOperatorKind op) + { + auto const fdecl = lhs->getDirectCallee(); + if (fdecl == nullptr) + { + return; + } + loplugin::DeclCheck dc(fdecl); + if (!(dc.Function("strlen").StdNamespace() || dc.Function("strlen").GlobalNamespace())) + { + return; + } + if (rhs->isValueDependent()) + { + return; + } + auto const val = rhs->getIntegerConstantExpr(compiler.getASTContext()); + if (!val) + { + return; + } + switch (op) + { + case BO_LT: + if (val->getExtValue() == 1) + { + report(DiagnosticsEngine::Warning, + "replace a comparison like 'strlen(e) < 1' with 'e[0] == '\\0''", + expr->getExprLoc()) + << expr->getSourceRange(); + } + break; + case BO_GT: + if (val->getExtValue() == 0) + { + report(DiagnosticsEngine::Warning, + "replace a comparison like 'strlen(e) > 0' with 'e[0] != '\\0''", + expr->getExprLoc()) + << expr->getSourceRange(); + } + break; + case BO_LE: + if (val->getExtValue() == 0) + { + report(DiagnosticsEngine::Warning, + "replace a comparison like 'strlen(e) <= 0' with 'e[0] == '\\0''", + expr->getExprLoc()) + << expr->getSourceRange(); + } + break; + case BO_GE: + if (val->getExtValue() == 1) + { + report(DiagnosticsEngine::Warning, + "replace a comparison like 'strlen(e) >= 1' with 'e[0] != '\\0''", + expr->getExprLoc()) + << expr->getSourceRange(); + } + break; + case BO_EQ: + if (val->getExtValue() == 0) + { + report(DiagnosticsEngine::Warning, + "replace a comparison like 'strlen(e) == 0' with 'e[0] == '\\0''", + expr->getExprLoc()) + << expr->getSourceRange(); + } + break; + case BO_NE: + if (val->getExtValue() == 0) + { + report(DiagnosticsEngine::Warning, + "replace a comparison like 'strlen(e) != 0' with 'e[0] != '\\0''", + expr->getExprLoc()) + << expr->getSourceRange(); + } + break; + default: + assert(false); + } + } + + void visitComparison(BinaryOperator const* expr) + { + if (ignoreLocation(expr)) + { + return; + } + if (auto const call = dyn_cast<CallExpr>(expr->getLHS()->IgnoreParenImpCasts())) + { + visitComparison(expr, call, expr->getRHS(), expr->getOpcode()); + } + else if (auto const call = dyn_cast<CallExpr>(expr->getRHS()->IgnoreParenImpCasts())) + { + visitComparison(expr, call, expr->getLHS(), reverse(expr->getOpcode())); + } + } +}; + +loplugin::Plugin::Registration<Empty> emptyRegistration("empty"); +} + +#endif // LO_CLANG_SHARED_PLUGINS + +/* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */ |