542fb709a4
when passing data to a method that is of type Foo&& Change-Id: I0e6bcfb42d6ebcbc7cb19e510ab2010a2cc2bb7e Reviewed-on: https://gerrit.libreoffice.org/c/core/+/121843 Tested-by: Jenkins Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>
352 lines
14 KiB
C++
352 lines
14 KiB
C++
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4; fill-column: 100 -*- */
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/*
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* This file is part of the LibreOffice project.
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*
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/.
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*/
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#ifndef LO_CLANG_SHARED_PLUGINS
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#include "check.hxx"
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#include "compat.hxx"
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#include "plugin.hxx"
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#include <iostream>
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#include <fstream>
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#include <unordered_set>
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#include <vector>
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namespace
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{
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class RedundantFCast final : public loplugin::FilteringPlugin<RedundantFCast>
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{
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public:
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explicit RedundantFCast(loplugin::InstantiationData const& data)
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: FilteringPlugin(data)
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{
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}
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bool VisitReturnStmt(ReturnStmt const* returnStmt)
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{
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if (ignoreLocation(returnStmt))
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return true;
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Expr const* expr = returnStmt->getRetValue();
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if (!expr)
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return true;
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if (auto exprWithCleanups = dyn_cast<ExprWithCleanups>(expr))
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expr = exprWithCleanups->getSubExpr();
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if (auto cxxConstructExpr = dyn_cast<CXXConstructExpr>(expr))
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{
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if (cxxConstructExpr->getNumArgs() != 1)
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return true;
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expr = cxxConstructExpr->getArg(0);
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}
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if (auto materializeTemporaryExpr = dyn_cast<MaterializeTemporaryExpr>(expr))
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expr = compat::getSubExpr(materializeTemporaryExpr);
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auto cxxFunctionalCastExpr = dyn_cast<CXXFunctionalCastExpr>(expr);
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if (!cxxFunctionalCastExpr)
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return true;
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auto const t1 = cxxFunctionalCastExpr->getTypeAsWritten();
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auto const t2 = compat::getSubExprAsWritten(cxxFunctionalCastExpr)->getType();
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if (t1.getCanonicalType().getTypePtr() != t2.getCanonicalType().getTypePtr())
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return true;
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if (!loplugin::isOkToRemoveArithmeticCast(compiler.getASTContext(), t1, t2,
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cxxFunctionalCastExpr->getSubExpr()))
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{
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return true;
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}
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if (m_Seen.insert(cxxFunctionalCastExpr->getExprLoc()).second)
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report(DiagnosticsEngine::Warning, "redundant functional cast from %0 to %1",
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cxxFunctionalCastExpr->getExprLoc())
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<< t2 << t1 << cxxFunctionalCastExpr->getSourceRange();
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return true;
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}
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/* Check for the creation of unnecessary temporaries when calling a method that takes a param by const & */
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bool VisitCallExpr(CallExpr const* callExpr)
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{
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if (ignoreLocation(callExpr))
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return true;
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const FunctionDecl* functionDecl;
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if (isa<CXXMemberCallExpr>(callExpr))
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functionDecl = dyn_cast<CXXMemberCallExpr>(callExpr)->getMethodDecl();
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else
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functionDecl = callExpr->getDirectCallee();
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if (!functionDecl)
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return true;
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unsigned len = std::min(callExpr->getNumArgs(), functionDecl->getNumParams());
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for (unsigned i = 0; i < len; ++i)
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{
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// check if param is const&
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auto param = functionDecl->getParamDecl(i);
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auto lvalueType = param->getType()->getAs<LValueReferenceType>();
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if (!lvalueType)
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continue;
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if (!lvalueType->getPointeeType().isConstQualified())
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continue;
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auto paramClassOrStructType = lvalueType->getPointeeType()->getAs<RecordType>();
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if (!paramClassOrStructType)
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continue;
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// check for temporary and functional cast in argument expression
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auto arg = callExpr->getArg(i)->IgnoreImpCasts();
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auto materializeTemporaryExpr = dyn_cast<MaterializeTemporaryExpr>(arg);
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if (!materializeTemporaryExpr)
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continue;
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auto functionalCast = dyn_cast<CXXFunctionalCastExpr>(
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compat::getSubExpr(materializeTemporaryExpr)->IgnoreImpCasts());
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if (!functionalCast)
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continue;
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auto const t1 = functionalCast->getTypeAsWritten();
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auto const t2 = compat::getSubExprAsWritten(functionalCast)->getType();
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if (t1.getCanonicalType().getTypePtr() != t2.getCanonicalType().getTypePtr())
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continue;
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// Check that the underlying expression is of the same class/struct type as the param i.e. that we are not instantiating
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// something useful
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if (t1.getCanonicalType().getTypePtr() != paramClassOrStructType)
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continue;
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// Don't warn about (necessary) cast from braced-init-list in non-deduced contexts:
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if (lvalueType->getPointeeType()->getAs<SubstTemplateTypeParmType>() != nullptr
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&& loplugin::TypeCheck(t1).ClassOrStruct("initializer_list").StdNamespace()
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&& isa<CXXStdInitializerListExpr>(compat::getSubExprAsWritten(functionalCast)))
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{
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continue;
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}
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if (m_Seen.insert(arg->getExprLoc()).second)
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{
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report(DiagnosticsEngine::Warning, "redundant functional cast from %0 to %1",
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arg->getExprLoc())
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<< t2 << t1 << arg->getSourceRange();
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report(DiagnosticsEngine::Note, "in call to method here", param->getLocation())
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<< param->getSourceRange();
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}
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}
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return true;
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}
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/* Check for the creation of unnecessary temporaries when calling a constructor that takes a param by const & */
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bool VisitCXXConstructExpr(CXXConstructExpr const* callExpr)
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{
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if (ignoreLocation(callExpr))
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return true;
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const CXXConstructorDecl* functionDecl = callExpr->getConstructor();
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unsigned len = std::min(callExpr->getNumArgs(), functionDecl->getNumParams());
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for (unsigned i = 0; i < len; ++i)
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{
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// check if param is const&
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auto param = functionDecl->getParamDecl(i);
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auto rvalueType = param->getType()->getAs<RValueReferenceType>();
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if (!rvalueType)
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{
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auto lvalueType = param->getType()->getAs<LValueReferenceType>();
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if (!lvalueType)
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continue;
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if (!lvalueType->getPointeeType().isConstQualified())
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continue;
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}
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auto valueType = param->getType()->getAs<ReferenceType>();
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auto paramClassOrStructType = valueType->getPointeeType()->getAs<RecordType>();
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if (!paramClassOrStructType)
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continue;
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// check for temporary and functional cast in argument expression
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auto arg = compat::IgnoreParenImplicit(callExpr->getArg(i));
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auto functionalCast = dyn_cast<CXXFunctionalCastExpr>(arg);
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if (!functionalCast)
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continue;
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auto const t1 = functionalCast->getTypeAsWritten();
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auto const t2 = compat::getSubExprAsWritten(functionalCast)->getType();
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if (t1.getCanonicalType().getTypePtr() != t2.getCanonicalType().getTypePtr())
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continue;
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// Check that the underlying expression is of the same class/struct type as the param i.e. that we are not instantiating
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// something useful
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if (t1.getCanonicalType().getTypePtr() != paramClassOrStructType)
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continue;
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if (rvalueType)
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{
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// constructing a temporary to pass to a && argument is fine. But we will see that in the VisitFunctionalCast
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// method below and generate a warning. And we don't have enough context there to determine that we're
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// doing the wrong thing. So add the expression to the m_Seen list here to prevent that warning.
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m_Seen.insert(functionalCast->getExprLoc());
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continue;
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}
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if (m_Seen.insert(arg->getExprLoc()).second)
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{
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report(DiagnosticsEngine::Warning,
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"redundant functional cast from %0 to %1 in construct expression",
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arg->getExprLoc())
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<< t2 << t1 << arg->getSourceRange();
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report(DiagnosticsEngine::Note, "in call to method here", param->getLocation())
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<< param->getSourceRange();
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}
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}
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return true;
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}
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// Find redundant cast to std::function, where clang reports
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// two different types for the inner and outer
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bool isRedundantStdFunctionCast(CXXFunctionalCastExpr const* expr)
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{
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bool deduced = false;
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QualType target;
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auto const written = expr->getTypeAsWritten();
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if (auto const t1 = written->getAs<DeducedTemplateSpecializationType>())
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{
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auto const decl = t1->getTemplateName().getAsTemplateDecl();
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if (!decl)
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{
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return false;
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}
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if (!loplugin::DeclCheck(decl->getTemplatedDecl())
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.ClassOrStruct("function")
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.StdNamespace())
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{
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return false;
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}
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deduced = true;
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}
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else if (auto const t2 = written->getAs<TemplateSpecializationType>())
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{
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auto const decl = t2->getTemplateName().getAsTemplateDecl();
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if (!decl)
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{
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return false;
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}
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if (!loplugin::DeclCheck(decl->getTemplatedDecl())
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.ClassOrStruct("function")
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.StdNamespace())
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{
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return false;
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}
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if (t2->getNumArgs() != 1)
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{
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if (isDebugMode())
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{
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report(DiagnosticsEngine::Fatal,
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"TODO: unexpected std::function with %0 template arguments",
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expr->getExprLoc())
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<< t2->getNumArgs() << expr->getSourceRange();
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}
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return false;
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}
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if (t2->getArg(0).getKind() != TemplateArgument::Type)
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{
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if (isDebugMode())
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{
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report(DiagnosticsEngine::Fatal,
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"TODO: unexpected std::function with non-type template argument",
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expr->getExprLoc())
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<< expr->getSourceRange();
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}
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return false;
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}
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target = t2->getArg(0).getAsType();
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}
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else
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{
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return false;
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}
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auto cxxConstruct
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= dyn_cast<CXXConstructExpr>(compat::IgnoreParenImplicit(expr->getSubExpr()));
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if (!cxxConstruct)
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return false;
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auto const lambda
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= dyn_cast<LambdaExpr>(compat::IgnoreParenImplicit(cxxConstruct->getArg(0)));
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if (!lambda)
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return false;
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if (deduced)
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// std::function([...](Args)->Ret{...}) should always be redundant:
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return true;
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auto const decl = lambda->getCallOperator();
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std::vector<QualType> args;
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for (unsigned i = 0; i != decl->getNumParams(); ++i)
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{
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args.push_back(decl->getParamDecl(i)->getType());
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}
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auto const source
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= compiler.getASTContext().getFunctionType(decl->getReturnType(), args, {});
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// std::function<Ret1(Args1)>([...](Args2)->Ret2{...}) is redundant if target Ret1(Args1)
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// matches source Ret2(Args2):
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return target.getCanonicalType() == source.getCanonicalType();
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}
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bool VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr const* expr)
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{
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if (ignoreLocation(expr))
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return true;
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// specifying the name for an init-list is necessary sometimes
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if (isa<InitListExpr>(compat::IgnoreParenImplicit(expr->getSubExpr())))
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return true;
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if (isa<CXXStdInitializerListExpr>(compat::IgnoreParenImplicit(expr->getSubExpr())))
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return true;
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auto const t1 = expr->getTypeAsWritten();
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auto const t2 = compat::getSubExprAsWritten(expr)->getType();
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if (!(t1.getCanonicalType().getTypePtr() == t2.getCanonicalType().getTypePtr()
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|| isRedundantStdFunctionCast(expr)))
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{
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return true;
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}
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// (a) we do a lot of int/sal_Int32 kind of casts which might be platform necessary?
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// (b) we do bool/bool casts in unit tests to avoid one of the other plugins
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// so just ignore this kind of thing for now
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if (const auto* BT = dyn_cast<BuiltinType>(t1->getUnqualifiedDesugaredType()))
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{
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auto k = BT->getKind();
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if (k == BuiltinType::Double || k == BuiltinType::Float
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|| (k >= BuiltinType::Bool && k <= BuiltinType::Int128))
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return true;
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}
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if (const auto* BT = dyn_cast<BuiltinType>(t2->getUnqualifiedDesugaredType()))
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{
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auto k = BT->getKind();
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if (k == BuiltinType::Double || k == BuiltinType::Float
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|| (k >= BuiltinType::Bool && k <= BuiltinType::Int128))
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return true;
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}
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auto tc = loplugin::TypeCheck(t1);
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if (tc.Typedef("sal_Int32").GlobalNamespace())
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return true;
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if (m_Seen.insert(expr->getExprLoc()).second)
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report(DiagnosticsEngine::Warning, "redundant functional cast from %0 to %1",
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expr->getExprLoc())
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<< t2 << t1 << expr->getSourceRange();
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return true;
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}
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bool preRun() override
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{
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if (!compiler.getLangOpts().CPlusPlus)
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return false;
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std::string fn = handler.getMainFileName().str();
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loplugin::normalizeDotDotInFilePath(fn);
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// necessary on some other platforms
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if (fn == SRCDIR "/sal/osl/unx/socket.cxx")
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return false;
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// compile-time check of constant
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if (fn == SRCDIR "/bridges/source/jni_uno/jni_bridge.cxx")
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return false;
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// TODO constructing a temporary to pass to a && param
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if (fn == SRCDIR "/sc/source/ui/view/viewfunc.cxx")
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return false;
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return true;
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}
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void run() override
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{
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if (preRun())
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TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
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}
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std::unordered_set<SourceLocation> m_Seen;
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};
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static loplugin::Plugin::Registration<RedundantFCast> redundantfcast("redundantfcast");
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} // namespace
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#endif // LO_CLANG_SHARED_PLUGINS
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/* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */
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