1 files changed, 206 insertions, 0 deletions
diff --git a/compilerplugins/clang/fieldcast.cxx b/compilerplugins/clang/fieldcast.cxx
new file mode 100644
index 0000000000..0807aef9b3
--- /dev/null
+++ b/compilerplugins/clang/fieldcast.cxx
@@ -0,0 +1,206 @@
+/* -*- 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/.
+ */
+
+#if !defined _WIN32 //TODO, #include <sys/file.h>
+
+#include <cassert>
+#include <string>
+#include <iostream>
+#include <fstream>
+#include <unordered_set>
+#include <vector>
+#include <algorithm>
+#include <sys/file.h>
+#include <unistd.h>
+
+#include "config_clang.h"
+
+#include "plugin.hxx"
+#include "compat.hxx"
+#include "check.hxx"
+
+#include "clang/AST/ParentMapContext.h"
+
+/**
+  Look for class fields that are always cast to some subtype,
+  which indicates that they should probably just be declared to be that subtype.
+
+  TODO add checking for dynamic_cast/static_cast on
+      unique_ptr
+      shared_ptr
+*/
+
+namespace
+{
+struct MyFieldInfo
+{
+    std::string parentClass;
+    std::string fieldName;
+    std::string fieldType;
+    std::string sourceLocation;
+};
+
+// try to limit the voluminous output a little
+static std::unordered_multimap<const FieldDecl*, const CXXRecordDecl*> castMap;
+
+class FieldCast : public loplugin::FilteringPlugin<FieldCast>
+{
+public:
+    explicit FieldCast(loplugin::InstantiationData const& data)
+        : FilteringPlugin(data)
+    {
+    }
+
+    virtual void run() override;
+
+    bool VisitCXXStaticCastExpr(const CXXStaticCastExpr*);
+    bool VisitCXXDynamicCastExpr(const CXXDynamicCastExpr*);
+    bool VisitCXXReinterpretCastExpr(const CXXReinterpretCastExpr*);
+
+private:
+    MyFieldInfo niceName(const FieldDecl*);
+    void checkCast(const CXXNamedCastExpr*);
+};
+
+void FieldCast::run()
+{
+    handler.enableTreeWideAnalysisMode();
+
+    TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
+
+    if (!isUnitTestMode())
+    {
+        // dump all our output in one write call - this is to try and limit IO "crosstalk" between multiple processes
+        // writing to the same logfile
+        std::string output;
+        output.reserve(64 * 1024);
+        for (const auto& pair : castMap)
+        {
+            MyFieldInfo s = niceName(pair.first);
+            output += "cast:\t" + s.parentClass //
+                      + "\t" + s.fieldName //
+                      + "\t" + s.fieldType //
+                      + "\t" + s.sourceLocation //
+                      + "\t" + pair.second->getQualifiedNameAsString() //
+                      + "\n";
+        }
+        std::ofstream myfile;
+        myfile.open(WORKDIR "/loplugin.fieldcast.log", std::ios::app | std::ios::out);
+        myfile << output;
+        myfile.close();
+    }
+    else
+    {
+        for (const auto& pair : castMap)
+            report(DiagnosticsEngine::Warning, "cast %0", pair.first->getBeginLoc())
+                << pair.second->getQualifiedNameAsString();
+    }
+}
+
+MyFieldInfo FieldCast::niceName(const FieldDecl* fieldDecl)
+{
+    MyFieldInfo aInfo;
+
+    const RecordDecl* recordDecl = fieldDecl->getParent();
+
+    if (const CXXRecordDecl* cxxRecordDecl = dyn_cast<CXXRecordDecl>(recordDecl))
+    {
+        if (cxxRecordDecl->getTemplateInstantiationPattern())
+            cxxRecordDecl = cxxRecordDecl->getTemplateInstantiationPattern();
+        aInfo.parentClass = cxxRecordDecl->getQualifiedNameAsString();
+    }
+    else
+    {
+        aInfo.parentClass = recordDecl->getQualifiedNameAsString();
+    }
+
+    aInfo.fieldName = fieldDecl->getNameAsString();
+    // sometimes the name (if it's an anonymous thing) contains the full path of the build folder, which we don't need
+    size_t idx = aInfo.fieldName.find(SRCDIR);
+    if (idx != std::string::npos)
+    {
+        aInfo.fieldName = aInfo.fieldName.replace(idx, strlen(SRCDIR), "");
+    }
+    aInfo.fieldType = fieldDecl->getType().getAsString();
+
+    SourceLocation expansionLoc
+        = compiler.getSourceManager().getExpansionLoc(fieldDecl->getLocation());
+    StringRef name = getFilenameOfLocation(expansionLoc);
+    aInfo.sourceLocation
+        = std::string(name.substr(strlen(SRCDIR) + 1)) + ":"
+          + std::to_string(compiler.getSourceManager().getSpellingLineNumber(expansionLoc));
+    loplugin::normalizeDotDotInFilePath(aInfo.sourceLocation);
+
+    return aInfo;
+}
+
+bool FieldCast::VisitCXXDynamicCastExpr(const CXXDynamicCastExpr* expr)
+{
+    checkCast(expr);
+    return true;
+}
+
+bool FieldCast::VisitCXXStaticCastExpr(const CXXStaticCastExpr* expr)
+{
+    checkCast(expr);
+    return true;
+}
+
+bool FieldCast::VisitCXXReinterpretCastExpr(const CXXReinterpretCastExpr* expr)
+{
+    checkCast(expr);
+    return true;
+}
+
+void FieldCast::checkCast(const CXXNamedCastExpr* expr)
+{
+    if (ignoreLocation(expr))
+        return;
+    if (isInUnoIncludeFile(compiler.getSourceManager().getSpellingLoc(expr->getBeginLoc())))
+        return;
+    auto castToType = expr->getTypeAsWritten()->getPointeeCXXRecordDecl();
+    if (!castToType)
+        return;
+    const Expr* subExpr = compat::getSubExprAsWritten(expr);
+    const FieldDecl* fieldDecl = nullptr;
+    if (const MemberExpr* memberExpr = dyn_cast_or_null<MemberExpr>(subExpr->IgnoreImplicit()))
+    {
+        fieldDecl = dyn_cast_or_null<FieldDecl>(memberExpr->getMemberDecl());
+    }
+    else if (const CXXMemberCallExpr* memberCallExpr
+             = dyn_cast_or_null<CXXMemberCallExpr>(subExpr->IgnoreImplicit()))
+    {
+        if (!memberCallExpr->getMethodDecl()->getIdentifier()
+            || memberCallExpr->getMethodDecl()->getName() != "get")
+            return;
+        const MemberExpr* memberExpr = dyn_cast_or_null<MemberExpr>(
+            memberCallExpr->getImplicitObjectArgument()->IgnoreImplicit());
+        if (!memberExpr)
+            return;
+        fieldDecl = dyn_cast_or_null<FieldDecl>(memberExpr->getMemberDecl());
+    }
+    if (!fieldDecl)
+        return;
+    if (isInUnoIncludeFile(compiler.getSourceManager().getSpellingLoc(fieldDecl->getBeginLoc())))
+        return;
+
+    // ignore casting to a less specific type
+    auto castFromType = subExpr->getType()->getPointeeCXXRecordDecl();
+    if (castFromType && castFromType->isDerivedFrom(castToType))
+        return;
+
+    castMap.emplace(fieldDecl, castToType);
+}
+
+loplugin::Plugin::Registration<FieldCast> X("fieldcast", false);
+}
+
+#endif
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */