Adding upstream version 4:7.4.7.upstream/4%7.4.7upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 357 insertions, 0 deletions

diff --git a/compilerplugins/clang/redundantfcast.cxx b/compilerplugins/clang/redundantfcast.cxx
new file mode 100644
index 000000000..38a7daf9f
--- /dev/null
+++ b/compilerplugins/clang/redundantfcast.cxx
@@ -0,0 +1,357 @@
+/* -*- 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 "check.hxx"
+#include "compat.hxx"
+#include "plugin.hxx"
+#include <iostream>
+#include <fstream>
+#include <unordered_set>
+#include <vector>
+
+namespace
+{
+class RedundantFCast final : public loplugin::FilteringPlugin<RedundantFCast>
+{
+public:
+    explicit RedundantFCast(loplugin::InstantiationData const& data)
+        : FilteringPlugin(data)
+    {
+    }
+
+    bool VisitReturnStmt(ReturnStmt const* returnStmt)
+    {
+        if (ignoreLocation(returnStmt))
+            return true;
+        Expr const* expr = returnStmt->getRetValue();
+        if (!expr)
+            return true;
+        if (auto exprWithCleanups = dyn_cast<ExprWithCleanups>(expr))
+            expr = exprWithCleanups->getSubExpr();
+        if (auto cxxConstructExpr = dyn_cast<CXXConstructExpr>(expr))
+        {
+            if (cxxConstructExpr->getNumArgs() != 1)
+                return true;
+            expr = cxxConstructExpr->getArg(0);
+        }
+        if (auto materializeTemporaryExpr = dyn_cast<MaterializeTemporaryExpr>(expr))
+            expr = materializeTemporaryExpr->getSubExpr();
+        auto cxxFunctionalCastExpr = dyn_cast<CXXFunctionalCastExpr>(expr);
+        if (!cxxFunctionalCastExpr)
+            return true;
+        auto const t1 = cxxFunctionalCastExpr->getTypeAsWritten();
+        auto const t2 = compat::getSubExprAsWritten(cxxFunctionalCastExpr)->getType();
+        if (t1.getCanonicalType().getTypePtr() != t2.getCanonicalType().getTypePtr())
+            return true;
+        if (!loplugin::isOkToRemoveArithmeticCast(compiler.getASTContext(), t1, t2,
+                                                  cxxFunctionalCastExpr->getSubExpr()))
+        {
+            return true;
+        }
+        if (m_Seen.insert(cxxFunctionalCastExpr->getExprLoc()).second)
+        {
+            if (suppressWarningAt(cxxFunctionalCastExpr->getBeginLoc()))
+            {
+                return true;
+            }
+            report(DiagnosticsEngine::Warning, "redundant functional cast from %0 to %1",
+                   cxxFunctionalCastExpr->getExprLoc())
+                << t2 << t1 << cxxFunctionalCastExpr->getSourceRange();
+        }
+        return true;
+    }
+
+    /* Check for the creation of unnecessary temporaries when calling a method that takes a param by const & */
+    bool VisitCallExpr(CallExpr const* callExpr)
+    {
+        if (ignoreLocation(callExpr))
+            return true;
+        const FunctionDecl* functionDecl;
+        if (isa<CXXMemberCallExpr>(callExpr))
+            functionDecl = dyn_cast<CXXMemberCallExpr>(callExpr)->getMethodDecl();
+        else
+            functionDecl = callExpr->getDirectCallee();
+        if (!functionDecl)
+            return true;
+
+        unsigned len = std::min(callExpr->getNumArgs(), functionDecl->getNumParams());
+        for (unsigned i = 0; i < len; ++i)
+        {
+            // check if param is const&
+            auto param = functionDecl->getParamDecl(i);
+            auto lvalueType = param->getType()->getAs<LValueReferenceType>();
+            if (!lvalueType)
+                continue;
+            if (!lvalueType->getPointeeType().isConstQualified())
+                continue;
+            auto paramClassOrStructType = lvalueType->getPointeeType()->getAs<RecordType>();
+            if (!paramClassOrStructType)
+                continue;
+            // check for temporary and functional cast in argument expression
+            auto arg = callExpr->getArg(i)->IgnoreImpCasts();
+            auto materializeTemporaryExpr = dyn_cast<MaterializeTemporaryExpr>(arg);
+            if (!materializeTemporaryExpr)
+                continue;
+            auto functionalCast = dyn_cast<CXXFunctionalCastExpr>(
+                materializeTemporaryExpr->getSubExpr()->IgnoreImpCasts());
+            if (!functionalCast)
+                continue;
+            auto const t1 = functionalCast->getTypeAsWritten();
+            auto const t2 = compat::getSubExprAsWritten(functionalCast)->getType();
+            if (t1.getCanonicalType().getTypePtr() != t2.getCanonicalType().getTypePtr())
+                continue;
+            // Check that the underlying expression is of the same class/struct type as the param i.e. that we are not instantiating
+            // something useful
+            if (t1.getCanonicalType().getTypePtr() != paramClassOrStructType)
+                continue;
+            // Don't warn about (necessary) cast from braced-init-list in non-deduced contexts:
+            if (lvalueType->getPointeeType()->getAs<SubstTemplateTypeParmType>() != nullptr
+                && loplugin::TypeCheck(t1).ClassOrStruct("initializer_list").StdNamespace()
+                && isa<CXXStdInitializerListExpr>(compat::getSubExprAsWritten(functionalCast)))
+            {
+                continue;
+            }
+
+            if (m_Seen.insert(arg->getExprLoc()).second)
+            {
+                report(DiagnosticsEngine::Warning, "redundant functional cast from %0 to %1",
+                       arg->getExprLoc())
+                    << t2 << t1 << arg->getSourceRange();
+                report(DiagnosticsEngine::Note, "in call to method here", param->getLocation())
+                    << param->getSourceRange();
+            }
+        }
+        return true;
+    }
+
+    /* Check for the creation of unnecessary temporaries when calling a constructor that takes a param by const & */
+    bool VisitCXXConstructExpr(CXXConstructExpr const* callExpr)
+    {
+        if (ignoreLocation(callExpr))
+            return true;
+        const CXXConstructorDecl* functionDecl = callExpr->getConstructor();
+
+        unsigned len = std::min(callExpr->getNumArgs(), functionDecl->getNumParams());
+        for (unsigned i = 0; i < len; ++i)
+        {
+            // check if param is const&
+            auto param = functionDecl->getParamDecl(i);
+            auto rvalueType = param->getType()->getAs<RValueReferenceType>();
+            if (!rvalueType)
+            {
+                auto lvalueType = param->getType()->getAs<LValueReferenceType>();
+                if (!lvalueType)
+                    continue;
+                if (!lvalueType->getPointeeType().isConstQualified())
+                    continue;
+            }
+            auto valueType = param->getType()->getAs<ReferenceType>();
+            auto paramClassOrStructType = valueType->getPointeeType()->getAs<RecordType>();
+            if (!paramClassOrStructType)
+                continue;
+            // check for temporary and functional cast in argument expression
+            auto arg = compat::IgnoreParenImplicit(callExpr->getArg(i));
+            auto functionalCast = dyn_cast<CXXFunctionalCastExpr>(arg);
+            if (!functionalCast)
+                continue;
+            auto const t1 = functionalCast->getTypeAsWritten();
+            auto const t2 = compat::getSubExprAsWritten(functionalCast)->getType();
+            if (t1.getCanonicalType().getTypePtr() != t2.getCanonicalType().getTypePtr())
+                continue;
+            // Check that the underlying expression is of the same class/struct type as the param i.e. that we are not instantiating
+            // something useful
+            if (t1.getCanonicalType().getTypePtr() != paramClassOrStructType)
+                continue;
+            if (rvalueType)
+            {
+                // constructing a temporary to pass to a && argument is fine. But we will see that in the VisitFunctionalCast
+                // method below and generate a warning. And we don't have enough context there to determine that we're
+                // doing the wrong thing. So add the expression to the m_Seen list here to prevent that warning.
+                m_Seen.insert(functionalCast->getExprLoc());
+                continue;
+            }
+
+            if (m_Seen.insert(arg->getExprLoc()).second)
+            {
+                if (suppressWarningAt(arg->getBeginLoc()))
+                {
+                    continue;
+                }
+                report(DiagnosticsEngine::Warning,
+                       "redundant functional cast from %0 to %1 in construct expression",
+                       arg->getExprLoc())
+                    << t2 << t1 << arg->getSourceRange();
+                report(DiagnosticsEngine::Note, "in call to method here", param->getLocation())
+                    << param->getSourceRange();
+            }
+        }
+        return true;
+    }
+
+    // Find redundant cast to std::function, where clang reports
+    // two different types for the inner and outer
+    bool isRedundantStdFunctionCast(CXXFunctionalCastExpr const* expr)
+    {
+        bool deduced = false;
+        QualType target;
+        auto const written = expr->getTypeAsWritten();
+        if (auto const t1 = written->getAs<DeducedTemplateSpecializationType>())
+        {
+            auto const decl = t1->getTemplateName().getAsTemplateDecl();
+            if (!decl)
+            {
+                return false;
+            }
+            if (!loplugin::DeclCheck(decl->getTemplatedDecl())
+                     .ClassOrStruct("function")
+                     .StdNamespace())
+            {
+                return false;
+            }
+            deduced = true;
+        }
+        else if (auto const t2 = written->getAs<TemplateSpecializationType>())
+        {
+            auto const decl = t2->getTemplateName().getAsTemplateDecl();
+            if (!decl)
+            {
+                return false;
+            }
+            if (!loplugin::DeclCheck(decl->getTemplatedDecl())
+                     .ClassOrStruct("function")
+                     .StdNamespace())
+            {
+                return false;
+            }
+            if (t2->getNumArgs() != 1)
+            {
+                if (isDebugMode())
+                {
+                    report(DiagnosticsEngine::Fatal,
+                           "TODO: unexpected std::function with %0 template arguments",
+                           expr->getExprLoc())
+                        << t2->getNumArgs() << expr->getSourceRange();
+                }
+                return false;
+            }
+            if (t2->getArg(0).getKind() != TemplateArgument::Type)
+            {
+                if (isDebugMode())
+                {
+                    report(DiagnosticsEngine::Fatal,
+                           "TODO: unexpected std::function with non-type template argument",
+                           expr->getExprLoc())
+                        << expr->getSourceRange();
+                }
+                return false;
+            }
+            target = t2->getArg(0).getAsType();
+        }
+        else
+        {
+            return false;
+        }
+        auto cxxConstruct
+            = dyn_cast<CXXConstructExpr>(compat::IgnoreParenImplicit(expr->getSubExpr()));
+        if (!cxxConstruct)
+            return false;
+        auto const lambda
+            = dyn_cast<LambdaExpr>(compat::IgnoreParenImplicit(cxxConstruct->getArg(0)));
+        if (!lambda)
+            return false;
+        if (deduced)
+            // std::function([...](Args)->Ret{...}) should always be redundant:
+            return true;
+        auto const decl = lambda->getCallOperator();
+        std::vector<QualType> args;
+        for (unsigned i = 0; i != decl->getNumParams(); ++i)
+        {
+            args.push_back(decl->getParamDecl(i)->getType());
+        }
+        auto const source
+            = compiler.getASTContext().getFunctionType(decl->getReturnType(), args, {});
+        // std::function<Ret1(Args1)>([...](Args2)->Ret2{...}) is redundant if target Ret1(Args1)
+        // matches source Ret2(Args2):
+        return target.getCanonicalType() == source.getCanonicalType();
+    }
+
+    bool VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr const* expr)
+    {
+        if (ignoreLocation(expr))
+            return true;
+        // specifying the name for an init-list is necessary sometimes
+        if (isa<InitListExpr>(compat::IgnoreParenImplicit(expr->getSubExpr())))
+            return true;
+        if (isa<CXXStdInitializerListExpr>(compat::IgnoreParenImplicit(expr->getSubExpr())))
+            return true;
+        auto const t1 = expr->getTypeAsWritten();
+        auto const t2 = compat::getSubExprAsWritten(expr)->getType();
+        if (!(t1.getCanonicalType().getTypePtr() == t2.getCanonicalType().getTypePtr()
+              || isRedundantStdFunctionCast(expr)))
+        {
+            return true;
+        }
+        // (a) we do a lot of int/sal_Int32 kind of casts which might be platform necessary?
+        // (b) we do bool/bool casts in unit tests to avoid one of the other plugins
+        // so just ignore this kind of thing for now
+        if (const auto* BT = dyn_cast<BuiltinType>(t1->getUnqualifiedDesugaredType()))
+        {
+            auto k = BT->getKind();
+            if (k == BuiltinType::Double || k == BuiltinType::Float
+                || (k >= BuiltinType::Bool && k <= BuiltinType::Int128))
+                return true;
+        }
+        if (const auto* BT = dyn_cast<BuiltinType>(t2->getUnqualifiedDesugaredType()))
+        {
+            auto k = BT->getKind();
+            if (k == BuiltinType::Double || k == BuiltinType::Float
+                || (k >= BuiltinType::Bool && k <= BuiltinType::Int128))
+                return true;
+        }
+        auto tc = loplugin::TypeCheck(t1);
+        if (tc.Typedef("sal_Int32").GlobalNamespace())
+            return true;
+
+        if (m_Seen.insert(expr->getExprLoc()).second)
+        {
+            if (suppressWarningAt(expr->getBeginLoc()))
+            {
+                return true;
+            }
+            report(DiagnosticsEngine::Warning, "redundant functional cast from %0 to %1",
+                   expr->getExprLoc())
+                << t2 << t1 << expr->getSourceRange();
+        }
+        return true;
+    }
+
+    bool preRun() override
+    {
+        if (!compiler.getLangOpts().CPlusPlus)
+            return false;
+        return true;
+    }
+
+    void run() override
+    {
+        if (preRun())
+            TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
+    }
+
+    std::unordered_set<SourceLocation> m_Seen;
+};
+
+static loplugin::Plugin::Registration<RedundantFCast> redundantfcast("redundantfcast");
+
+} // namespace
+
+#endif // LO_CLANG_SHARED_PLUGINS
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */