cc26cfd379
Change-Id: I539e6aedad61d80b6ebe80104b77d720072395bd
413 lines
14 KiB
C++
413 lines
14 KiB
C++
/* -*- 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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// Original idea from tml.
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// Look for variables that are (a) initialised from zero or one constants. (b) only used in one spot.
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// In which case, we might as well inline it.
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namespace
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{
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Expr const * lookThroughInitListExpr(Expr const * expr) {
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if (auto const ile = dyn_cast<InitListExpr>(expr->IgnoreParenImpCasts())) {
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if (ile->getNumInits() == 1) {
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return ile->getInit(0);
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}
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}
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return expr;
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}
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class ConstantValueDependentExpressionVisitor:
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public ConstStmtVisitor<ConstantValueDependentExpressionVisitor, bool>
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{
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ASTContext const & context_;
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public:
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ConstantValueDependentExpressionVisitor(ASTContext const & context):
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context_(context) {}
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bool Visit(Stmt const * stmt) {
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assert(isa<Expr>(stmt));
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auto const expr = cast<Expr>(stmt);
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if (!expr->isValueDependent()) {
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return expr->isEvaluatable(context_);
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}
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return ConstStmtVisitor::Visit(stmt);
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}
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bool VisitParenExpr(ParenExpr const * expr)
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{ return Visit(expr->getSubExpr()); }
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bool VisitCastExpr(CastExpr const * expr) {
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return Visit(expr->getSubExpr());
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}
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bool VisitUnaryOperator(UnaryOperator const * expr)
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{ return Visit(expr->getSubExpr()); }
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bool VisitBinaryOperator(BinaryOperator const * expr) {
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return Visit(expr->getLHS()) && Visit(expr->getRHS());
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}
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bool VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr const *) {
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return true;
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}
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};
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class OnceVar:
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public loplugin::FilteringPlugin<OnceVar>
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{
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public:
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explicit OnceVar(loplugin::InstantiationData const & data): FilteringPlugin(data) {}
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virtual void run() override {
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// ignore some files with problematic macros
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std::string fn(handler.getMainFileName());
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loplugin::normalizeDotDotInFilePath(fn);
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// platform-specific stuff
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if (fn == SRCDIR "/sal/osl/unx/thread.cxx"
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|| fn == SRCDIR "/sot/source/base/formats.cxx"
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|| fn == SRCDIR "/svl/source/config/languageoptions.cxx"
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|| fn == SRCDIR "/sfx2/source/appl/appdde.cxx"
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|| fn == SRCDIR "/configmgr/source/components.cxx"
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|| fn == SRCDIR "/embeddedobj/source/msole/oleembed.cxx")
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return;
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// some of this is necessary
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if (loplugin::hasPathnamePrefix( fn, SRCDIR "/sal/qa/"))
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return;
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if (loplugin::hasPathnamePrefix( fn, SRCDIR "/comphelper/qa/"))
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return;
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// TODO need to check calls via function pointer
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if (fn == SRCDIR "/i18npool/source/textconversion/textconversion_zh.cxx"
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|| fn == SRCDIR "/i18npool/source/localedata/localedata.cxx")
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return;
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// debugging stuff
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if (fn == SRCDIR "/sc/source/core/data/dpcache.cxx"
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|| fn == SRCDIR "/sw/source/core/layout/dbg_lay.cxx"
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|| fn == SRCDIR "/sw/source/core/layout/ftnfrm.cxx")
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return;
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// TODO taking local reference to variable
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if (fn == SRCDIR "/sc/source/filter/excel/xechart.cxx")
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return;
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// macros managing to generate to a valid warning
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if (fn == SRCDIR "/solenv/bin/concat-deps.c")
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return;
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// TODO bug in the plugin
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if (fn == SRCDIR "/vcl/unx/generic/app/saldisp.cxx")
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return;
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TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
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for (auto const & varDecl : maVarDeclSet)
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{
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if (maVarDeclToIgnoreSet.find(varDecl) != maVarDeclToIgnoreSet.end())
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continue;
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int noUses = 0;
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auto it = maVarUsesMap.find(varDecl);
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if (it != maVarUsesMap.end())
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noUses = it->second;
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if (noUses > 1)
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continue;
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report(DiagnosticsEngine::Warning,
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"var used only once, should be inlined or declared const",
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varDecl->getLocation())
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<< varDecl->getSourceRange();
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if (it != maVarUsesMap.end())
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report(DiagnosticsEngine::Note,
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"used here",
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maVarUseSourceRangeMap[varDecl].getBegin())
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<< maVarUseSourceRangeMap[varDecl];
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}
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}
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bool VisitMemberExpr(MemberExpr const * expr) {
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// ignore cases like:
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// const OUString("xxx") xxx;
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// rtl_something(xxx.pData);
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// where we cannot inline the declaration.
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if (isa<FieldDecl>(expr->getMemberDecl())) {
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recordIgnore(expr);
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}
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return true;
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}
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bool VisitUnaryOperator(UnaryOperator const * expr) {
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// if we take the address of it, or we modify it, ignore it
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UnaryOperator::Opcode op = expr->getOpcode();
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if (op == UO_AddrOf || op == UO_PreInc || op == UO_PostInc
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|| op == UO_PreDec || op == UO_PostDec)
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{
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recordIgnore(expr->getSubExpr());
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}
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return true;
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}
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bool VisitBinaryOperator(BinaryOperator const * expr) {
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// if we assign it another value, or modify it, ignore it
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BinaryOperator::Opcode op = expr->getOpcode();
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if (op == BO_Assign || op == BO_PtrMemD || op == BO_PtrMemI || op == BO_MulAssign
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|| op == BO_DivAssign || op == BO_RemAssign || op == BO_AddAssign
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|| op == BO_SubAssign || op == BO_ShlAssign || op == BO_ShrAssign
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|| op == BO_AndAssign || op == BO_XorAssign || op == BO_OrAssign)
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{
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recordIgnore(expr->getLHS());
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}
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return true;
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}
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bool VisitCallExpr(CallExpr const * expr) {
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unsigned firstArg = 0;
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if (auto const cmce = dyn_cast<CXXMemberCallExpr>(expr)) {
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if (auto const e1 = cmce->getMethodDecl()) {
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if (!(e1->isConst() || e1->isStatic())) {
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recordIgnore(cmce->getImplicitObjectArgument());
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}
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} else if (auto const e2 = dyn_cast<BinaryOperator>(
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cmce->getCallee()->IgnoreParenImpCasts()))
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{
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switch (e2->getOpcode()) {
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case BO_PtrMemD:
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case BO_PtrMemI:
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if (!e2->getRHS()->getType()->getAs<MemberPointerType>()
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->getPointeeType()->getAs<FunctionProtoType>()
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->isConst())
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{
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recordIgnore(e2->getLHS());
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}
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break;
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default:
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break;
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}
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}
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} else if (auto const coce = dyn_cast<CXXOperatorCallExpr>(expr)) {
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if (auto const cmd = dyn_cast_or_null<CXXMethodDecl>(
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coce->getDirectCallee()))
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{
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if (!cmd->isStatic()) {
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assert(coce->getNumArgs() != 0);
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if (!cmd->isConst()) {
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recordIgnore(coce->getArg(0));
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}
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firstArg = 1;
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}
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}
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}
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// ignore those ones we are passing by reference
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const FunctionDecl* calleeFunctionDecl = expr->getDirectCallee();
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if (calleeFunctionDecl) {
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for (unsigned i = firstArg; i < expr->getNumArgs(); ++i) {
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if (i < calleeFunctionDecl->getNumParams()) {
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QualType qt { calleeFunctionDecl->getParamDecl(i)->getType() };
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if (loplugin::TypeCheck(qt).LvalueReference().NonConst()) {
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recordIgnore(expr->getArg(i));
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}
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if (loplugin::TypeCheck(qt).Pointer().NonConst()) {
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recordIgnore(expr->getArg(i));
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}
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}
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}
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}
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return true;
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}
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bool VisitCXXConstructExpr(CXXConstructExpr const * expr) {
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// ignore those ones we are passing by reference
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const CXXConstructorDecl* cxxConstructorDecl = expr->getConstructor();
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for (unsigned i = 0; i < expr->getNumArgs(); ++i) {
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if (i < cxxConstructorDecl->getNumParams()) {
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QualType qt { cxxConstructorDecl->getParamDecl(i)->getType() };
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if (loplugin::TypeCheck(qt).LvalueReference().NonConst()) {
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recordIgnore(expr->getArg(i));
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}
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if (loplugin::TypeCheck(qt).Pointer().NonConst()) {
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recordIgnore(expr->getArg(i));
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}
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}
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}
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return true;
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}
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bool VisitDeclRefExpr( const DeclRefExpr* );
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bool VisitVarDecl( const VarDecl* );
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bool TraverseFunctionDecl( FunctionDecl* functionDecl );
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private:
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std::unordered_set<VarDecl const *> maVarDeclSet;
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std::unordered_set<VarDecl const *> maVarDeclToIgnoreSet;
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std::unordered_map<VarDecl const *, int> maVarUsesMap;
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std::unordered_map<VarDecl const *, SourceRange> maVarUseSourceRangeMap;
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bool isConstantValueDependentExpression(Expr const * expr) {
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return ConstantValueDependentExpressionVisitor(compiler.getASTContext())
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.Visit(expr);
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}
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void recordIgnore(Expr const * expr) {
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for (;;) {
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expr = expr->IgnoreParenImpCasts();
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if (auto const e = dyn_cast<MemberExpr>(expr)) {
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if (isa<FieldDecl>(e->getMemberDecl())) {
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expr = e->getBase();
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continue;
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}
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}
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if (auto const e = dyn_cast<ArraySubscriptExpr>(expr)) {
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expr = e->getBase();
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continue;
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}
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if (auto const e = dyn_cast<BinaryOperator>(expr)) {
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if (e->getOpcode() == BO_PtrMemD) {
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expr = e->getLHS();
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continue;
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}
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}
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break;
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}
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auto const dre = dyn_cast<DeclRefExpr>(expr);
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if (dre == nullptr) {
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return;
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}
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auto const var = dyn_cast<VarDecl>(dre->getDecl());
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if (var == nullptr) {
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return;
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}
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maVarDeclToIgnoreSet.insert(var);
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}
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};
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bool OnceVar::TraverseFunctionDecl( FunctionDecl* functionDecl )
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{
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// Ignore functions that contains #ifdef-ery, can be quite tricky
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// to make useful changes when this plugin fires in such functions
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if (containsPreprocessingConditionalInclusion(
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functionDecl->getSourceRange()))
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return true;
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return RecursiveASTVisitor::TraverseFunctionDecl(functionDecl);
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}
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bool OnceVar::VisitVarDecl( const VarDecl* varDecl )
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{
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if (ignoreLocation(varDecl)) {
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return true;
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}
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if (auto const init = varDecl->getInit()) {
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recordIgnore(lookThroughInitListExpr(init));
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}
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if (varDecl->isExceptionVariable() || isa<ParmVarDecl>(varDecl)) {
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return true;
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}
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// ignore stuff in header files (which should really not be there, but anyhow)
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if (!compiler.getSourceManager().isInMainFile(varDecl->getLocation())) {
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return true;
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}
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// Ignore macros like FD_ZERO
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if (compiler.getSourceManager().isMacroBodyExpansion(compat::getBeginLoc(varDecl))) {
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return true;
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}
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if (varDecl->hasGlobalStorage()) {
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return true;
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}
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auto const tc = loplugin::TypeCheck(varDecl->getType());
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if (!varDecl->getType().isCXX11PODType(compiler.getASTContext())
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&& !tc.Class("OString").Namespace("rtl").GlobalNamespace()
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&& !tc.Class("OUString").Namespace("rtl").GlobalNamespace()
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&& !tc.Class("OStringBuffer").Namespace("rtl").GlobalNamespace()
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&& !tc.Class("OUStringBuffer").Namespace("rtl").GlobalNamespace()
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&& !tc.Class("Color").GlobalNamespace()
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&& !tc.Class("Pair").GlobalNamespace()
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&& !tc.Class("Point").GlobalNamespace()
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&& !tc.Class("Size").GlobalNamespace()
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&& !tc.Class("Range").GlobalNamespace()
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&& !tc.Class("Selection").GlobalNamespace()
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&& !tc.Class("Rectangle").Namespace("tools").GlobalNamespace())
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{
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return true;
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}
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if (varDecl->getType()->isPointerType())
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return true;
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// if it's declared const, ignore it, it's there to make the code easier to read
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if (tc.Const())
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return true;
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if (!varDecl->hasInit())
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return true;
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// check for string or scalar literals
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bool foundStringLiteral = false;
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const Expr * initExpr = varDecl->getInit();
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if (auto e = dyn_cast<ExprWithCleanups>(initExpr)) {
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initExpr = e->getSubExpr();
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}
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if (isa<clang::StringLiteral>(initExpr)) {
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foundStringLiteral = true;
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} else if (auto constructExpr = dyn_cast<CXXConstructExpr>(initExpr)) {
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if (constructExpr->getNumArgs() == 0) {
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foundStringLiteral = true; // i.e., empty string
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} else {
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auto stringLit2 = dyn_cast<clang::StringLiteral>(constructExpr->getArg(0));
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foundStringLiteral = stringLit2 != nullptr;
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}
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}
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if (!foundStringLiteral) {
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auto const init = varDecl->getInit();
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if (!(init->isValueDependent()
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? isConstantValueDependentExpression(init)
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: init->isConstantInitializer(
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compiler.getASTContext(), false/*ForRef*/)))
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{
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return true;
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}
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}
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maVarDeclSet.insert(varDecl);
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return true;
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}
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bool OnceVar::VisitDeclRefExpr( const DeclRefExpr* declRefExpr )
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{
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if (ignoreLocation(declRefExpr)) {
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return true;
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}
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const Decl* decl = declRefExpr->getDecl();
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if (!isa<VarDecl>(decl) || isa<ParmVarDecl>(decl)) {
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return true;
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}
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const VarDecl * varDecl = dyn_cast<VarDecl>(decl)->getCanonicalDecl();
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// ignore stuff in header files (which should really not be there, but anyhow)
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if (!compiler.getSourceManager().isInMainFile(varDecl->getLocation())) {
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return true;
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}
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if (maVarUsesMap.find(varDecl) == maVarUsesMap.end()) {
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maVarUsesMap[varDecl] = 1;
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maVarUseSourceRangeMap[varDecl] = declRefExpr->getSourceRange();
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} else {
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maVarUsesMap[varDecl]++;
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}
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return true;
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}
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loplugin::Plugin::Registration< OnceVar > X("oncevar", false);
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}
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/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
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