new loplugin sequentialassign
Look for places we are assigning to the same variable twice in succession, which means we can simplify that to a single assign Change-Id: I499d20e28f5595e81e927bef8e1bf364eea8ba91 Reviewed-on: https://gerrit.libreoffice.org/70531 Tested-by: Jenkins Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>
This commit is contained in:
Noel Grandin
331
compilerplugins/clang/sequentialassign.cxx
Normal file
331
compilerplugins/clang/sequentialassign.cxx
Normal file
@@ -0,0 +1,331 @@
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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
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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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#include <cassert>
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#include <string>
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#include <iostream>
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#include <unordered_map>
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#include <unordered_set>
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#include "plugin.hxx"
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#include "check.hxx"
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#include "clang/AST/CXXInheritance.h"
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#include "clang/AST/StmtVisitor.h"
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/**
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This is a kind of simplified dead-store analysis.
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We are looking for patterns like:
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Foo x = a;
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x = b;
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which can be simplified to
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x = b
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or
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Foo x = a;
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x = f(x)
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which can be simplified to
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Foo x = f(a)
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TODO Improve this plugin to make it safer. We should really be checking the following
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conditions inside the RHS of the second statement:
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If the variable is having it's address taken, or a non-const method called on it,
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on passed by non-const-ref.
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*/
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namespace
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{
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//static bool startswith(const std::string& rStr, const char* pSubStr) {
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// return rStr.compare(0, strlen(pSubStr), pSubStr) == 0;
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//}
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class SequentialAssign : public loplugin::FilteringPlugin<SequentialAssign>
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{
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public:
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explicit SequentialAssign(loplugin::InstantiationData const& data)
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: FilteringPlugin(data)
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{
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}
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virtual void run() override
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{
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std::string fn(handler.getMainFileName());
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loplugin::normalizeDotDotInFilePath(fn);
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// places where the existing code style just looks better
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// TODO lots of these would be unnecessary if I taught the plugin
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// to ignore vars which are assigned to repeatedly
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if (fn == SRCDIR "/vcl/source/helper/commandinfoprovider.cxx"
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|| fn == SRCDIR "/basegfx/source/polygon/b2dpolygonclipper.cxx"
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|| fn == SRCDIR "/i18nlangtag/source/isolang/insys.cxx"
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|| fn == SRCDIR "/vcl/unx/generic/fontmanager/fontconfig.cxx"
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|| fn == SRCDIR "/svtools/source/filter/exportdialog.cxx"
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|| fn == SRCDIR "/svtools/source/control/ruler.cxx"
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|| fn == SRCDIR "/basic/qa/cppunit/test_scanner.cxx"
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|| fn == SRCDIR "/basic/source/uno/namecont.cxx"
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|| fn == SRCDIR "/test/source/sheet/xnamedrange.cxx"
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|| fn == SRCDIR "/i18npool/qa/cppunit/test_breakiterator.cxx"
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|| fn == SRCDIR "/i18npool/source/localedata/LocaleNode.cxx"
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|| fn == SRCDIR "/i18npool/source/transliteration/transliteration_Ignore.cxx"
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|| fn == SRCDIR "/i18npool/qa/cppunit/test_textsearch.cxx"
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|| fn == SRCDIR "/framework/source/jobs/jobdata.cxx"
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|| fn == SRCDIR "/framework/source/services/pathsettings.cxx"
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|| fn == SRCDIR "/xmloff/source/chart/SchXMLTools.cxx"
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|| fn == SRCDIR "/svx/source/tbxctrls/Palette.cxx"
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|| fn == SRCDIR "/svx/source/sdr/contact/objectcontactofpageview.cxx"
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|| fn == SRCDIR "/svx/source/form/fmservs.cxx"
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|| fn == SRCDIR "/svx/source/svdraw/svdograf.cxx"
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|| fn == SRCDIR "/svx/source/accessibility/AccessibleShape.cxx"
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|| fn == SRCDIR "/svx/source/fmcomp/fmgridcl.cxx"
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|| fn == SRCDIR "/chart2/source/tools/CharacterProperties.cxx"
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|| fn == SRCDIR "/svx/source/dialog/dialcontrol.cxx"
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|| fn == SRCDIR "/connectivity/source/commontools/TTableHelper.cxx"
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|| fn == SRCDIR "/svx/source/dialog/_bmpmask.cxx"
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|| fn == SRCDIR "/media/noel/disk2/libo4/cui/source/dialogs/SignSignatureLineDialog.cxx"
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|| fn == SRCDIR "/filter/source/msfilter/msdffimp.cxx"
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|| fn == SRCDIR "/filter/source/flash/swffilter.cxx"
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|| fn == SRCDIR "/cui/source/dialogs/SignSignatureLineDialog.cxx"
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|| fn == SRCDIR "/cui/source/dialogs/screenshotannotationdlg.cxx"
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|| fn == SRCDIR "/cui/source/options/optupdt.cxx"
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|| fn == SRCDIR "/dbaccess/source/ui/querydesign/querycontroller.cxx"
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|| fn == SRCDIR "/dbaccess/source/ui/dlg/DbAdminImpl.cxx"
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|| fn == SRCDIR "/dbaccess/source/ui/querydesign/JoinController.cxx"
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|| fn == SRCDIR "/dbaccess/source/ui/misc/TokenWriter.cxx"
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|| fn == SRCDIR "/dbaccess/source/ui/misc/TokenWriter.cxx"
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|| fn == SRCDIR "/dbaccess/source/ui/misc/dbsubcomponentcontroller.cxx"
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|| fn == SRCDIR "/dbaccess/source/core/api/querycomposer.cxx"
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|| fn == SRCDIR "/desktop/source/lib/init.cxx"
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|| fn == SRCDIR "/lotuswordpro/source/filter/lwpfribmark.cxx"
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|| fn == SRCDIR "/tools/qa/cppunit/test_color.cxx"
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|| fn == SRCDIR "/sc/qa/unit/ucalc.cxx"
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|| fn == SRCDIR "/sc/source/ui/view/printfun.cxx"
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|| fn == SRCDIR "/sc/source/ui/view/preview.cxx"
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|| fn == SRCDIR "/sw/source/core/doc/tblafmt.cxx"
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|| fn == SRCDIR "/sw/source/core/draw/dflyobj.cxx"
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|| fn == SRCDIR "/sw/source/core/doc/DocumentDrawModelManager.cxx"
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|| fn == SRCDIR "/sw/source/core/edit/edfcol.cxx"
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|| fn == SRCDIR "/sw/source/filter/ww8/ww8toolbar.cxx"
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|| fn == SRCDIR "/sw/source/ui/fldui/fldvar.cxx"
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|| fn == SRCDIR "/sw/source/filter/ww8/ww8atr.cxx"
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|| fn == SRCDIR "/sd/source/ui/accessibility/AccessiblePageShape.cxx"
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|| fn == SRCDIR "/xmlsecurity/source/xmlsec/nss/nssinitializer.cxx"
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|| fn == SRCDIR "/sd/source/ui/slidesorter/cache/SlsRequestFactory.cxx"
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|| fn == SRCDIR "/sd/source/ui/framework/configuration/ResourceId.cxx"
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|| fn == SRCDIR "/sd/source/filter/html/htmlex.cxx"
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|| fn == SRCDIR "/starmath/source/cfgitem.cxx"
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|| fn == SRCDIR "/ucb/source/ucp/ftp/ftpurl.cxx"
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|| fn == SRCDIR "/starmath/source/node.cxx"
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|| fn == SRCDIR "/ucb/source/ucp/cmis/certvalidation_handler.cxx"
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|| fn == SRCDIR "/reportdesign/source/ui/inspection/GeometryHandler.cxx"
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|| fn == SRCDIR "/reportdesign/source/core/api/ReportDefinition.cxx"
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|| fn == SRCDIR "/test/source/table/tablerow.cxx"
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|| fn == SRCDIR "/basegfx/test/B2DHomMatrixTest.cxx"
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|| fn == SRCDIR "/comphelper/qa/unit/base64_test.cxx"
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|| fn == SRCDIR "/testtools/source/bridgetest/bridgetest.cxx"
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|| fn == SRCDIR "/comphelper/qa/string/test_string.cxx"
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|| fn == SRCDIR "/cppu/qa/test_unotype.cxx"
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|| fn == SRCDIR "/cppu/qa/cppumaker/test_cppumaker.cxx"
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|| fn == SRCDIR "/o3tl/qa/test-lru_map.cxx" || fn == SRCDIR "/svl/qa/unit/svl.cxx"
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|| fn == SRCDIR "/chart2/qa/extras/PivotChartTest.cxx"
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|| fn == SRCDIR "/chart2/qa/extras/chart2export.cxx"
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|| fn == SRCDIR "/writerfilter/qa/cppunittests/misc/misc.cxx"
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|| fn == SRCDIR "/sw/qa/extras/ww8export/ww8export.cxx"
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|| fn == SRCDIR "/sw/qa/extras/uiwriter/uiwriter.cxx")
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return;
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// inside ifdef
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if (fn == SRCDIR "/vcl/source/filter/png/pngread.cxx"
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|| fn == SRCDIR "/vcl/source/window/syschild.cxx"
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|| fn == SRCDIR "/sal/osl/unx/security.cxx"
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|| fn == SRCDIR "/vcl/source/filter/png/pngwrite.cxx"
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|| fn == SRCDIR "/svtools/source/control/inettbc.cxx"
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|| fn == SRCDIR "/canvas/source/cairo/cairo_textlayout.cxx"
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|| fn == SRCDIR "/sal/qa/osl/file/osl_File.cxx")
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return;
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// taking address of variable
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if (fn == SRCDIR "/vcl/unx/generic/dtrans/X11_selection.cxx")
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return;
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// other
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if (fn == SRCDIR "/sc/source/core/tool/scmatrix.cxx"
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|| fn == SRCDIR "/sal/qa/rtl/oustringbuffer/test_oustringbuffer_assign.cxx")
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return;
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TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
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}
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bool VisitCompoundStmt(CompoundStmt const*);
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private:
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const VarDecl* findSimpleAssign(Stmt const*);
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bool isSimpleRHS(Expr const*);
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Expr const* ignore(Expr const*);
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void checkForSecondAssign(Stmt const* firstStmt, Stmt const* stmt, VarDecl const* varDecl);
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};
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bool SequentialAssign::VisitCompoundStmt(CompoundStmt const* compoundStmt)
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{
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if (ignoreLocation(compoundStmt))
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return true;
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auto it = compoundStmt->body_begin();
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while (true)
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{
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if (it == compoundStmt->body_end())
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break;
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auto firstStmt = *it;
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const VarDecl* foundVars = findSimpleAssign(firstStmt);
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// reference types have slightly weird behaviour
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if (!foundVars || foundVars->getType()->isReferenceType())
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{
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++it;
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continue;
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}
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++it;
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if (it == compoundStmt->body_end())
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break;
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checkForSecondAssign(firstStmt, *it, foundVars);
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}
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return true;
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}
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void SequentialAssign::checkForSecondAssign(Stmt const* firstStmt, Stmt const* stmt,
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VarDecl const* varDecl)
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{
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if (auto exprCleanup = dyn_cast<ExprWithCleanups>(stmt))
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stmt = exprCleanup->getSubExpr();
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if (auto operatorCall = dyn_cast<CXXOperatorCallExpr>(stmt))
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{
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if (operatorCall->getOperator() == OO_Equal)
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{
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if (auto declRefExprLHS = dyn_cast<DeclRefExpr>(ignore(operatorCall->getArg(0))))
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if (declRefExprLHS->getDecl() == varDecl)
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{
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firstStmt->dump();
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report(DiagnosticsEngine::Warning,
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"simplify by merging with the preceding assignment",
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compat::getBeginLoc(stmt))
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<< stmt->getSourceRange();
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}
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}
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return;
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}
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if (auto binaryOp = dyn_cast<BinaryOperator>(stmt))
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{
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if (binaryOp->getOpcode() == BO_Assign)
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{
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if (auto declRefExpr = dyn_cast<DeclRefExpr>(ignore(binaryOp->getLHS())))
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if (declRefExpr->getDecl() == varDecl)
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{
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firstStmt->dump();
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report(DiagnosticsEngine::Warning,
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"simplify by merging with the preceding assignment",
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compat::getBeginLoc(stmt))
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<< stmt->getSourceRange();
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}
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}
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}
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}
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const VarDecl* SequentialAssign::findSimpleAssign(Stmt const* stmt)
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{
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if (auto declStmt = dyn_cast<DeclStmt>(stmt))
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if (declStmt->isSingleDecl())
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if (auto varDeclLHS = dyn_cast_or_null<VarDecl>(declStmt->getSingleDecl()))
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{
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if (varDeclLHS->getStorageDuration() == SD_Static)
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return nullptr;
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// if it's call-style init (e.g. OUString s("xxx")), we only treat
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// it as simple if it only contains a variable in the call
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// (e.g. OUString s(x))
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if (varDeclLHS->getInitStyle() == VarDecl::InitializationStyle::CallInit)
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{
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auto cxxConstructExpr
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= dyn_cast<CXXConstructExpr>(ignore(varDeclLHS->getInit()));
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if (cxxConstructExpr)
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{
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if (cxxConstructExpr->getNumArgs() == 0)
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return varDeclLHS;
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if (cxxConstructExpr->getNumArgs() > 1)
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return nullptr;
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if (!isa<DeclRefExpr>(ignore(cxxConstructExpr->getArg(0))))
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return nullptr;
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}
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}
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if (auto init = varDeclLHS->getInit())
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if (isSimpleRHS(init))
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return varDeclLHS;
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}
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if (auto operatorCall = dyn_cast<CXXOperatorCallExpr>(stmt))
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if (operatorCall->getOperator() == OO_Equal)
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if (auto declRefExprLHS = dyn_cast<DeclRefExpr>(ignore(operatorCall->getArg(0))))
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if (auto varDeclLHS = dyn_cast<VarDecl>(declRefExprLHS->getDecl()))
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if (isSimpleRHS(operatorCall->getArg(1)))
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return varDeclLHS;
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if (auto binaryOp = dyn_cast<BinaryOperator>(stmt))
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if (binaryOp->getOpcode() == BO_Assign)
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if (auto declRefExprLHS = dyn_cast<DeclRefExpr>(ignore(binaryOp->getLHS())))
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if (auto varDeclLHS = dyn_cast<VarDecl>(declRefExprLHS->getDecl()))
|
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if (isSimpleRHS(binaryOp->getRHS()))
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return varDeclLHS;
|
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return nullptr;
|
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}
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|
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/**
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Does the first statement have a relatively simply RHS we can inline into the second statement?
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*/
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bool SequentialAssign::isSimpleRHS(Expr const* expr)
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{
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expr = ignore(expr);
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// code like
|
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// Point aCurPos = rGlyphs
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// always has a CXXConstructExpr wrapping the RHS
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if (auto cxxConstructExpr = dyn_cast<CXXConstructExpr>(expr))
|
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if (cxxConstructExpr->getNumArgs() == 1)
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expr = ignore(cxxConstructExpr->getArg(0));
|
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|
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if (!expr->isValueDependent()
|
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&& expr->isConstantInitializer(compiler.getASTContext(), false /*ForRef*/))
|
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return true;
|
||||
if (isa<CXXMemberCallExpr>(expr))
|
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return false;
|
||||
if (isa<CXXOperatorCallExpr>(expr))
|
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return false;
|
||||
if (isa<UserDefinedLiteral>(expr))
|
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return true;
|
||||
if (isa<CallExpr>(expr))
|
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return false;
|
||||
if (isa<CastExpr>(expr))
|
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return false;
|
||||
if (isa<ArraySubscriptExpr>(expr))
|
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return false;
|
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if (isa<BinaryOperator>(expr))
|
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return false;
|
||||
if (isa<ConditionalOperator>(expr))
|
||||
return false;
|
||||
if (isa<UnaryOperator>(expr))
|
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return false;
|
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if (isa<CXXNewExpr>(expr))
|
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return false;
|
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if (auto memberExpr = dyn_cast<MemberExpr>(expr))
|
||||
return isSimpleRHS(memberExpr->getBase());
|
||||
|
||||
return true;
|
||||
}
|
||||
|
||||
Expr const* SequentialAssign::ignore(Expr const* expr)
|
||||
{
|
||||
return expr->IgnoreImplicit()->IgnoreParens()->IgnoreImplicit();
|
||||
}
|
||||
|
||||
// Off by default because of safety concerns, see TODO at top
|
||||
loplugin::Plugin::Registration<SequentialAssign> X("sequentialassign", false);
|
||||
}
|
||||
|
||||
/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
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||||
95
compilerplugins/clang/test/sequentialassign.cxx
Normal file
95
compilerplugins/clang/test/sequentialassign.cxx
Normal file
@@ -0,0 +1,95 @@
|
||||
/* -*- 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/.
|
||||
*/
|
||||
|
||||
#include <rtl/ustring.hxx>
|
||||
|
||||
namespace test1
|
||||
{
|
||||
void f(OUString s1)
|
||||
{
|
||||
OUString s2 = s1;
|
||||
// expected-error@+1 {{simplify by merging with the preceding assignment [loplugin:sequentialassign]}}
|
||||
s2 = s2.getToken(0, '(');
|
||||
}
|
||||
}
|
||||
|
||||
namespace test2
|
||||
{
|
||||
OUString s2;
|
||||
void f(OUString s1)
|
||||
{
|
||||
s2 = s1;
|
||||
// expected-error@+1 {{simplify by merging with the preceding assignment [loplugin:sequentialassign]}}
|
||||
s2 = s2.getToken(0, '(');
|
||||
}
|
||||
}
|
||||
|
||||
namespace test3
|
||||
{
|
||||
struct VolumeInfo
|
||||
{
|
||||
OUString getFileSystemName();
|
||||
};
|
||||
OUString aNullURL("");
|
||||
void f(VolumeInfo _aVolumeInfo)
|
||||
{
|
||||
OUString aFileSysName(aNullURL);
|
||||
// expected-error@+1 {{simplify by merging with the preceding assignment [loplugin:sequentialassign]}}
|
||||
aFileSysName = _aVolumeInfo.getFileSystemName();
|
||||
}
|
||||
}
|
||||
|
||||
namespace test4
|
||||
{
|
||||
struct B3DVector
|
||||
{
|
||||
B3DVector getPerpendicular();
|
||||
};
|
||||
void f(B3DVector aNewVPN)
|
||||
{
|
||||
B3DVector aNewToTheRight = aNewVPN;
|
||||
// expected-error@+1 {{simplify by merging with the preceding assignment [loplugin:sequentialassign]}}
|
||||
aNewToTheRight = aNewToTheRight.getPerpendicular();
|
||||
}
|
||||
}
|
||||
|
||||
namespace test5
|
||||
{
|
||||
void f(OUString s, int x)
|
||||
{
|
||||
int nPos = x;
|
||||
// expected-error@+1 {{simplify by merging with the preceding assignment [loplugin:sequentialassign]}}
|
||||
nPos = s.indexOf("x", nPos);
|
||||
}
|
||||
}
|
||||
|
||||
namespace test6
|
||||
{
|
||||
void f()
|
||||
{
|
||||
OUString s2("xxxx");
|
||||
s2 = s2.getToken(0, '('); // no warning expected
|
||||
}
|
||||
}
|
||||
|
||||
namespace test7
|
||||
{
|
||||
class Class1
|
||||
{
|
||||
OUString m_field1;
|
||||
void foo(Class1& rOther)
|
||||
{
|
||||
OUString s = rOther.m_field1;
|
||||
// expected-error@+1 {{simplify by merging with the preceding assignment [loplugin:sequentialassign]}}
|
||||
s = s.copy(1, 2);
|
||||
}
|
||||
};
|
||||
}
|
||||
|
||||
/* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */
|
||||
@@ -51,6 +51,7 @@ $(eval $(call gb_CompilerTest_add_exception_objects,compilerplugins_clang, \
|
||||
compilerplugins/clang/test/salcall \
|
||||
compilerplugins/clang/test/sallogareas \
|
||||
compilerplugins/clang/test/salunicodeliteral \
|
||||
compilerplugins/clang/test/sequentialassign \
|
||||
compilerplugins/clang/test/shouldreturnbool \
|
||||
compilerplugins/clang/test/simplifybool \
|
||||
compilerplugins/clang/test/simplifyconstruct \
|
||||
|
||||
Reference in New Issue
Block a user