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-rw-r--r--compilerplugins/clang/trivialconstructor.cxx156
1 files changed, 156 insertions, 0 deletions
diff --git a/compilerplugins/clang/trivialconstructor.cxx b/compilerplugins/clang/trivialconstructor.cxx
new file mode 100644
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+++ b/compilerplugins/clang/trivialconstructor.cxx
@@ -0,0 +1,156 @@
+/* -*- 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 <unordered_map>
+#include <unordered_set>
+
+#include "plugin.hxx"
+#include "check.hxx"
+#include "config_clang.h"
+#include "clang/AST/CXXInheritance.h"
+#include "clang/AST/StmtVisitor.h"
+
+// Look for declared constructors that can be trivial (and therefore don't need to be declared)
+
+namespace
+{
+class TrivialConstructor : public loplugin::FilteringPlugin<TrivialConstructor>
+{
+public:
+ explicit TrivialConstructor(loplugin::InstantiationData const& data)
+ : FilteringPlugin(data)
+ {
+ }
+
+ virtual void run() override { TraverseDecl(compiler.getASTContext().getTranslationUnitDecl()); }
+
+ bool VisitCXXConstructorDecl(CXXConstructorDecl const*);
+
+private:
+ bool HasTrivialConstructorBody(const CXXRecordDecl* BaseClassDecl,
+ const CXXRecordDecl* MostDerivedClassDecl);
+ bool FieldHasTrivialConstructorBody(const FieldDecl* Field);
+};
+
+bool TrivialConstructor::VisitCXXConstructorDecl(CXXConstructorDecl const* constructorDecl)
+{
+ if (ignoreLocation(constructorDecl))
+ return true;
+ if (!constructorDecl->hasTrivialBody())
+ return true;
+ if (constructorDecl->isExplicit())
+ return true;
+ if (!constructorDecl->isDefaultConstructor())
+ return true;
+ if (constructorDecl->getNumParams() != 0)
+ return true;
+ if (!constructorDecl->inits().empty())
+ return true;
+ if (constructorDecl->getExceptionSpecType() != EST_None)
+ return true;
+ if (constructorDecl->getAccess() != AS_public)
+ return true;
+ if (!constructorDecl->isThisDeclarationADefinition())
+ return true;
+ if (isInUnoIncludeFile(
+ compiler.getSourceManager().getSpellingLoc(constructorDecl->getLocation())))
+ return true;
+ const CXXRecordDecl* recordDecl = constructorDecl->getParent();
+ if (std::distance(recordDecl->ctor_begin(), recordDecl->ctor_end()) != 1)
+ return true;
+ // Constructor templates are not included in ctor_begin()..ctor_end() above, so also do a slow
+ // check across all decls():
+ for (auto d : recordDecl->decls())
+ {
+ if (auto const d2 = dyn_cast<FunctionTemplateDecl>(d))
+ {
+ if (isa<CXXConstructorDecl>(d2->getTemplatedDecl()))
+ {
+ return true;
+ }
+ }
+ }
+ if (!HasTrivialConstructorBody(recordDecl, recordDecl))
+ return true;
+
+ report(DiagnosticsEngine::Warning, "no need for explicit constructor decl",
+ constructorDecl->getLocation())
+ << constructorDecl->getSourceRange();
+ if (constructorDecl->getCanonicalDecl() != constructorDecl)
+ {
+ constructorDecl = constructorDecl->getCanonicalDecl();
+ report(DiagnosticsEngine::Warning, "no need for explicit constructor decl",
+ constructorDecl->getLocation())
+ << constructorDecl->getSourceRange();
+ }
+ return true;
+}
+
+bool TrivialConstructor::HasTrivialConstructorBody(const CXXRecordDecl* BaseClassDecl,
+ const CXXRecordDecl* MostDerivedClassDecl)
+{
+ if (BaseClassDecl != MostDerivedClassDecl && !BaseClassDecl->hasTrivialDefaultConstructor())
+ return false;
+
+ // Check fields.
+ for (const auto* field : BaseClassDecl->fields())
+ if (!FieldHasTrivialConstructorBody(field))
+ return false;
+
+ // Check non-virtual bases.
+ for (const auto& I : BaseClassDecl->bases())
+ {
+ if (I.isVirtual())
+ continue;
+ if (!I.getType()->isRecordType())
+ continue;
+ const CXXRecordDecl* NonVirtualBase = I.getType()->getAsCXXRecordDecl();
+ if (NonVirtualBase && !HasTrivialConstructorBody(NonVirtualBase, MostDerivedClassDecl))
+ return false;
+ }
+
+ if (BaseClassDecl == MostDerivedClassDecl)
+ {
+ // Check virtual bases.
+ for (const auto& I : BaseClassDecl->vbases())
+ {
+ if (!I.getType()->isRecordType())
+ continue;
+ const CXXRecordDecl* VirtualBase = I.getType()->getAsCXXRecordDecl();
+ if (VirtualBase && !HasTrivialConstructorBody(VirtualBase, MostDerivedClassDecl))
+ return false;
+ }
+ }
+ return true;
+}
+
+bool TrivialConstructor::FieldHasTrivialConstructorBody(const FieldDecl* Field)
+{
+ QualType FieldBaseElementType = compiler.getASTContext().getBaseElementType(Field->getType());
+
+ const RecordType* RT = FieldBaseElementType->getAs<RecordType>();
+ if (!RT)
+ return true;
+
+ CXXRecordDecl* FieldClassDecl = cast<CXXRecordDecl>(RT->getDecl());
+
+ // The constructor for an implicit anonymous union member is never invoked.
+ if (FieldClassDecl->isUnion() && FieldClassDecl->isAnonymousStructOrUnion())
+ return false;
+
+ return FieldClassDecl->hasTrivialDefaultConstructor();
+}
+
+loplugin::Plugin::Registration<TrivialConstructor> X("trivialconstructor", true);
+}
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */