1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*
 * This file is part of the LibreOffice project.
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 */

#include <cassert>
#include <string>
#include <iostream>
#include <fstream>
#include <set>
#include "plugin.hxx"

/**
Look for fields that are only ever assigned a single constant value.

We dmp a list of values assigned to fields, and a list of field definitions.
Then we will post-process the 2 lists and find the set of interesting fields.

Be warned that it produces around 5G of log file.

The process goes something like this:
  $ make check
  $ make FORCE_COMPILE_ALL=1 COMPILER_PLUGIN_TOOL='singlevalfields' check
  $ ./compilerplugins/clang/singlevalfields.py

Note that the actual process may involve a fair amount of undoing, hand editing, and general messing around
to get it to work :-)

@TODO we don't spot fields that have been zero-initialised via calloc or rtl_allocateZeroMemory or memset
@TODO calls to lambdas where a reference to the field is taken

*/

namespace {

struct MyFieldInfo
{
    FieldDecl const * fieldDecl;
    std::string parentClass;
    std::string fieldName;
    std::string fieldType;
    std::string sourceLocation;
};
bool operator < (const MyFieldInfo &lhs, const MyFieldInfo &rhs)
{
    return std::tie(lhs.parentClass, lhs.fieldName)
         < std::tie(rhs.parentClass, rhs.fieldName);
}

struct MyFieldAssignmentInfo : public MyFieldInfo
{
    std::string value;
};

bool operator < (const MyFieldAssignmentInfo &lhs, const MyFieldAssignmentInfo &rhs)
{
    return std::tie(lhs.parentClass, lhs.fieldName, lhs.value)
         < std::tie(rhs.parentClass, rhs.fieldName, rhs.value);
}


// try to limit the voluminous output a little
static std::set<MyFieldAssignmentInfo> assignedSet;
static std::set<MyFieldInfo> definitionSet;


class SingleValFields:
    public RecursiveASTVisitor<SingleValFields>, public loplugin::Plugin
{
public:
    explicit SingleValFields(loplugin::InstantiationData const & data):
        Plugin(data) {}

    virtual void run() override
    {
        TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());

        if (!isUnitTestMode())
        {
            // dump all our output in one write call - this is to try and limit IO "crosstalk" between multiple processes
            // writing to the same logfile
            std::string output;
            for (const MyFieldAssignmentInfo & s : assignedSet)
                output += "asgn:\t" + s.parentClass + "\t" + s.fieldName + "\t" + s.value + "\n";<--- Consider using std::accumulate algorithm instead of a raw loop.
            for (const MyFieldInfo & s : definitionSet)
                output += "defn:\t" + s.parentClass + "\t" + s.fieldName + "\t" + s.fieldType + "\t" + s.sourceLocation + "\n";<--- Consider using std::accumulate algorithm instead of a raw loop.
            std::ofstream myfile;
            myfile.open( WORKDIR "/loplugin.singlevalfields.log", std::ios::app | std::ios::out);
            myfile << output;
            myfile.close();
        }
        else
        {
            for (const MyFieldAssignmentInfo & s : assignedSet)
                if (s.fieldDecl && compiler.getSourceManager().isInMainFile(compat::getBeginLoc(s.fieldDecl)))
                    report(
                        DiagnosticsEngine::Warning,
                        "assign %0",
                        compat::getBeginLoc(s.fieldDecl))
                        << s.value;
        }
    }

    bool shouldVisitTemplateInstantiations () const { return true; }
    // to catch compiler-generated constructors
    bool shouldVisitImplicitCode() const { return true; }

    bool VisitFieldDecl( const FieldDecl* );
    bool VisitVarDecl( const VarDecl* );
    bool VisitMemberExpr( const MemberExpr* );
    bool VisitDeclRefExpr( const DeclRefExpr* );
    bool VisitCXXConstructorDecl( const CXXConstructorDecl* );
//    bool VisitUnaryExprOrTypeTraitExpr( const UnaryExprOrTypeTraitExpr* );
private:
    void niceName(const DeclaratorDecl*, MyFieldInfo&);
    void walkPotentialAssign( const DeclaratorDecl* fieldOrVarDecl, const Stmt* stmt );
    std::string getExprValue(const Expr*);
    const FunctionDecl* get_top_FunctionDecl_from_Stmt(const Stmt&);
    void checkCallExpr(const Stmt* child, const CallExpr* callExpr, std::string& assignValue, bool& bPotentiallyAssignedTo);
};

void SingleValFields::niceName(const DeclaratorDecl* fieldOrVarDecl, MyFieldInfo& aInfo)
{
    const VarDecl* varDecl = dyn_cast<VarDecl>(fieldOrVarDecl);
    const FieldDecl* fieldDecl = dyn_cast<FieldDecl>(fieldOrVarDecl);
    aInfo.fieldDecl = fieldDecl;
    if (fieldDecl)
        aInfo.parentClass = fieldDecl->getParent()->getQualifiedNameAsString();
    else
    {
        if (auto parentRecordDecl = dyn_cast<CXXRecordDecl>(varDecl->getDeclContext()))
            aInfo.parentClass = parentRecordDecl->getQualifiedNameAsString();
        else if (auto parentMethodDecl = dyn_cast<CXXMethodDecl>(varDecl->getDeclContext()))
            aInfo.parentClass = parentMethodDecl->getQualifiedNameAsString();
        else if (auto parentFunctionDecl = dyn_cast<FunctionDecl>(varDecl->getDeclContext()))
            aInfo.parentClass = parentFunctionDecl->getQualifiedNameAsString();
        else if (isa<TranslationUnitDecl>(varDecl->getDeclContext()))
            aInfo.parentClass = handler.getMainFileName();
        else if (auto parentNamespaceDecl = dyn_cast<NamespaceDecl>(varDecl->getDeclContext()))
            aInfo.parentClass = parentNamespaceDecl->getQualifiedNameAsString();
        else if (isa<LinkageSpecDecl>(varDecl->getDeclContext()))
            aInfo.parentClass = "extern"; // what to do here?
        else
        {
            std::cout << "what is this? " << varDecl->getDeclContext()->getDeclKindName() << std::endl;
            exit(1);
        }
    }
    aInfo.fieldName = fieldOrVarDecl->getNameAsString();
    aInfo.fieldType = fieldOrVarDecl->getType().getAsString();

    SourceLocation expansionLoc = compiler.getSourceManager().getExpansionLoc( fieldOrVarDecl->getLocation() );
    StringRef name = compiler.getSourceManager().getFilename(expansionLoc);
    aInfo.sourceLocation = std::string(name.substr(strlen(SRCDIR)+1)) + ":" + std::to_string(compiler.getSourceManager().getSpellingLineNumber(expansionLoc));
    loplugin::normalizeDotDotInFilePath(aInfo.sourceLocation);
}

bool SingleValFields::VisitFieldDecl( const FieldDecl* fieldDecl )
{
    auto canonicalDecl = fieldDecl->getCanonicalDecl();

    if( ignoreLocation( canonicalDecl )
        || isInUnoIncludeFile( compiler.getSourceManager().getSpellingLoc(canonicalDecl->getLocation())) )
        return true;

    MyFieldInfo aInfo;<--- Shadowed declaration
    niceName(canonicalDecl, aInfo);
    definitionSet.insert(aInfo);

    if (fieldDecl->getInClassInitializer())
    {
        MyFieldAssignmentInfo aInfo;<--- Shadow variable
        niceName(canonicalDecl, aInfo);
        aInfo.value = getExprValue(fieldDecl->getInClassInitializer());
        assignedSet.insert(aInfo);
    }

    return true;
}

bool SingleValFields::VisitVarDecl( const VarDecl* varDecl )
{
    if (isa<ParmVarDecl>(varDecl))
        return true;
    if (varDecl->getType().isConstQualified())
        return true;
    if (!(varDecl->isStaticLocal() || varDecl->isStaticDataMember() || varDecl->hasGlobalStorage()))
        return true;

    auto canonicalDecl = varDecl->getCanonicalDecl();
    if (!canonicalDecl->getLocation().isValid())
        return true;

    if( ignoreLocation( canonicalDecl )
        || isInUnoIncludeFile( compiler.getSourceManager().getSpellingLoc(canonicalDecl->getLocation())) )
        return true;

    MyFieldInfo aInfo;<--- Shadowed declaration
    niceName(canonicalDecl, aInfo);
    definitionSet.insert(aInfo);

    if (varDecl->getInit())
    {
        MyFieldAssignmentInfo aInfo;<--- Shadow variable
        niceName(canonicalDecl, aInfo);
        aInfo.value = getExprValue(varDecl->getInit());
        assignedSet.insert(aInfo);
    }

    return true;
}

bool SingleValFields::VisitCXXConstructorDecl( const CXXConstructorDecl* decl )
{
    if( ignoreLocation( decl ) )
        return true;

    // doesn't count as a write to fields because it's self->self
    if (decl->isCopyOrMoveConstructor())
        return true;

    for(auto it = decl->init_begin(); it != decl->init_end(); ++it)
    {
        const CXXCtorInitializer* init = *it;
        const FieldDecl* fieldDecl = init->getMember();
        if( !fieldDecl )
            continue;
        MyFieldAssignmentInfo aInfo;
        niceName(fieldDecl, aInfo);
        const Expr * expr = init->getInit();
        // unwrap any single-arg constructors, this helps to find smart pointers
        // that are only assigned nullptr
        if (auto cxxConstructExpr = dyn_cast<CXXConstructExpr>(expr))
            if (cxxConstructExpr->getNumArgs() == 1)
                expr = cxxConstructExpr->getArg(0);
        aInfo.value = getExprValue(expr);
        assignedSet.insert(aInfo);
    }
    return true;
}

bool SingleValFields::VisitMemberExpr( const MemberExpr* memberExpr )
{
    const ValueDecl* decl = memberExpr->getMemberDecl();
    const FieldDecl* fieldDecl = dyn_cast<FieldDecl>(decl);
    if (!fieldDecl)
        return true;
    if (ignoreLocation(memberExpr))
        return true;
    walkPotentialAssign(fieldDecl, memberExpr);
    return true;
}

bool SingleValFields::VisitDeclRefExpr( const DeclRefExpr* declRefExpr )
{
    const VarDecl* varDecl = dyn_cast_or_null<VarDecl>(declRefExpr->getDecl());
    if (!varDecl)
        return true;
    if (isa<ParmVarDecl>(varDecl))
        return true;
    if (varDecl->getType().isConstQualified())
        return true;
    if (!(varDecl->isStaticLocal() || varDecl->isStaticDataMember() || varDecl->hasGlobalStorage()))
        return true;
    if (ignoreLocation(declRefExpr))
        return true;
    walkPotentialAssign(varDecl, declRefExpr);
    return true;
}

void SingleValFields::walkPotentialAssign( const DeclaratorDecl* fieldOrVarDecl, const Stmt* memberExpr )
{
    const FunctionDecl* parentFunction = getParentFunctionDecl(memberExpr);
    if (parentFunction)
    {
        auto methodDecl = dyn_cast<CXXMethodDecl>(parentFunction);
        if (methodDecl && (methodDecl->isCopyAssignmentOperator() || methodDecl->isMoveAssignmentOperator()))
           return;
        if (methodDecl && methodDecl->getIdentifier()
            && (methodDecl->getName().startswith("Clone") || methodDecl->getName().startswith("clone")))
           return;
        auto cxxConstructorDecl = dyn_cast<CXXConstructorDecl>(parentFunction);
        if (cxxConstructorDecl && cxxConstructorDecl->isCopyOrMoveConstructor())
           return;
    }

    // walk up the tree until we find something interesting
    const Stmt* child = memberExpr;
    const Stmt* parent = getParentStmt(memberExpr);
    bool bPotentiallyAssignedTo = false;
    bool bDump = false;
    std::string assignValue = "?";

    // check for field being returned by non-const ref eg. Foo& getFoo() { return f; }
    if (parentFunction && parent && isa<ReturnStmt>(parent)) {
        const Stmt* parent2 = getParentStmt(parent);
        if (parent2 && isa<CompoundStmt>(parent2)) {
            QualType qt = parentFunction->getReturnType().getDesugaredType(compiler.getASTContext());
            if (!qt.isConstQualified() && qt->isReferenceType()) {
                bPotentiallyAssignedTo = true;
            }
        }
    }

    while (!bPotentiallyAssignedTo) {
        // check for field being accessed by a reference variable e.g. Foo& f = m.foo;
        auto parentsList = compiler.getASTContext().getParents(*child);
        auto it = parentsList.begin();
        if (it != parentsList.end()) {
            const VarDecl *varDecl = it->get<VarDecl>();
            if (varDecl) {
                QualType qt = varDecl->getType().getDesugaredType(compiler.getASTContext());
                if (!qt.isConstQualified() && qt->isReferenceType()) {
                    bPotentiallyAssignedTo = true;
                    break;
                }
            }
        }

        if (!parent) {
            return;
        }
        if (isa<CastExpr>(parent) || isa<MemberExpr>(parent) || isa<ParenExpr>(parent) || isa<ParenListExpr>(parent)
             || isa<ExprWithCleanups>(parent))
        {
            child = parent;
            parent = getParentStmt(parent);
        }
        else if (isa<UnaryOperator>(parent))
        {
            const UnaryOperator* unaryOperator = dyn_cast<UnaryOperator>(parent);
            int x = unaryOperator->getOpcode();
            if (x == UO_AddrOf || x == UO_PostInc || x == UO_PostDec || x == UO_PreInc || x == UO_PreDec) {
                assignValue = "?";
                bPotentiallyAssignedTo = true;
                break;
            }
            // cannot be assigned to anymore
            break;
        }
        else if (auto callExpr = dyn_cast<CallExpr>(parent))
        {
            checkCallExpr(child, callExpr, assignValue, bPotentiallyAssignedTo);
            break;
        }
        else if (isa<CXXConstructExpr>(parent))
        {
            const CXXConstructExpr* consExpr = dyn_cast<CXXConstructExpr>(parent);
            const CXXConstructorDecl* consDecl = consExpr->getConstructor();
            for (unsigned i = 0; i < consExpr->getNumArgs(); ++i) {
                if (i >= consDecl->getNumParams()) // can happen in template code
                    break;
                if (consExpr->getArg(i) == child) {
                    const ParmVarDecl* parmVarDecl = consDecl->getParamDecl(i);
                    QualType qt = parmVarDecl->getType().getDesugaredType(compiler.getASTContext());
                    if (!qt.isConstQualified() && qt->isReferenceType()) {
                        bPotentiallyAssignedTo = true;
                    }
                    break;
                }
            }
            break;
        }
        else if (isa<BinaryOperator>(parent))
        {
            const BinaryOperator* binaryOp = dyn_cast<BinaryOperator>(parent);
            auto op = binaryOp->getOpcode();
            if ( binaryOp->getLHS() != child ) {
                // if the expr is on the RHS, do nothing
            }
            else if ( op == BO_Assign ) {
                assignValue = getExprValue(binaryOp->getRHS());
                bPotentiallyAssignedTo = true;
            } else if ( op == BO_MulAssign || op == BO_DivAssign
                        || op == BO_RemAssign || op == BO_AddAssign
                        || op == BO_SubAssign || op == BO_ShlAssign
                        || op == BO_ShrAssign || op == BO_AndAssign
                        || op == BO_XorAssign || op == BO_OrAssign )
            {
                bPotentiallyAssignedTo = true;
            }
            break;
        }
        else if ( isa<CompoundStmt>(parent)
                || isa<SwitchStmt>(parent) || isa<CaseStmt>(parent) || isa<DefaultStmt>(parent)
                || isa<DoStmt>(parent) || isa<WhileStmt>(parent)
                || isa<IfStmt>(parent)
                || isa<ForStmt>(parent)
                || isa<ReturnStmt>(parent)
                || isa<CXXNewExpr>(parent)
                || isa<CXXDeleteExpr>(parent)
                || isa<ConditionalOperator>(parent)
                || isa<CXXTypeidExpr>(parent)
                || isa<ArraySubscriptExpr>(parent)
                || isa<CXXDependentScopeMemberExpr>(parent)
                || isa<DeclStmt>(parent)
                || isa<UnaryExprOrTypeTraitExpr>(parent)
                || isa<UnresolvedMemberExpr>(parent)
                || isa<MaterializeTemporaryExpr>(parent)  //???
                || isa<InitListExpr>(parent)
                || isa<CXXUnresolvedConstructExpr>(parent)
                || isa<LambdaExpr>(parent)
                || isa<PackExpansionExpr>(parent)
                || isa<CXXPseudoDestructorExpr>(parent)
                )
        {
            break;
        }
        else if ( isa<ArrayInitLoopExpr>(parent) || isa<GCCAsmStmt>(parent) || isa<VAArgExpr>(parent))
        {
            bPotentiallyAssignedTo = true;
            break;
        }
        else {
            bPotentiallyAssignedTo = true;
            bDump = true;
            break;
        }
    }
    if (bDump)
    {
        report(
             DiagnosticsEngine::Warning,
             "oh dear, what can the matter be?",
              compat::getBeginLoc(memberExpr))
              << memberExpr->getSourceRange();
        parent->dump();
    }
    if (bPotentiallyAssignedTo)
    {
        MyFieldAssignmentInfo aInfo;
        niceName(fieldOrVarDecl, aInfo);
        aInfo.value = assignValue;
        assignedSet.insert(aInfo);
    }
}

void SingleValFields::checkCallExpr(const Stmt* child, const CallExpr* callExpr, std::string& assignValue, bool& bPotentiallyAssignedTo)
{
    if (callExpr->getCallee() == child) {
        return;
    }
    const FunctionDecl* functionDecl;
    if (auto memberCallExpr = dyn_cast<CXXMemberCallExpr>(callExpr)) {
        functionDecl = memberCallExpr->getMethodDecl();
    } else {
        functionDecl = callExpr->getDirectCallee();
    }
    if (functionDecl) {
        if (auto operatorCallExpr = dyn_cast<CXXOperatorCallExpr>(callExpr)) {
            if (operatorCallExpr->getArg(0) == child) {
                const CXXMethodDecl* calleeMethodDecl = dyn_cast_or_null<CXXMethodDecl>(operatorCallExpr->getDirectCallee());
                if (calleeMethodDecl) {
                    if (operatorCallExpr->getOperator() == OO_Equal) {
                        assignValue = getExprValue(operatorCallExpr->getArg(1));
                        bPotentiallyAssignedTo = true;
                        return;
                    }
                }
            }
        }
        for (unsigned i = 0; i < callExpr->getNumArgs(); ++i) {
            if (i >= functionDecl->getNumParams()) // can happen in template code
                break;
            if (callExpr->getArg(i) == child) {
                const ParmVarDecl* parmVarDecl = functionDecl->getParamDecl(i);
                QualType qt = parmVarDecl->getType().getDesugaredType(compiler.getASTContext());
                if (!qt.isConstQualified() && qt->isReferenceType()) {
                    assignValue = "?";
                    bPotentiallyAssignedTo = true;
                }
                break;
            }
        }
        return;
    }
    // check for function pointers
    const FieldDecl* calleeFieldDecl = dyn_cast_or_null<FieldDecl>(callExpr->getCalleeDecl());
    if (!calleeFieldDecl) {
        return;
    }
    QualType qt = calleeFieldDecl->getType().getDesugaredType(compiler.getASTContext());<--- Shadowed declaration
    if (!qt->isPointerType()) {
        return;
    }
    qt = qt->getPointeeType().getDesugaredType(compiler.getASTContext());
    const FunctionProtoType* proto = qt->getAs<FunctionProtoType>();
    if (!proto) {
        return;
    }
    for (unsigned i = 0; i < callExpr->getNumArgs(); ++i) {
        if (i >= proto->getNumParams()) // can happen in template code
            break;
        if (callExpr->getArg(i) == child) {
            QualType qt = proto->getParamType(i).getDesugaredType(compiler.getASTContext());<--- Shadow variable
            if (!qt.isConstQualified() && qt->isReferenceType()) {
                assignValue = "?";
                bPotentiallyAssignedTo = true;
            }
            break;
        }
    }
}


std::string SingleValFields::getExprValue(const Expr* arg)
{
    if (!arg)
        return "?";
    arg = arg->IgnoreParenCasts();
    arg = arg->IgnoreImplicit();
    // ignore this, it seems to trigger an infinite recursion
    if (isa<UnaryExprOrTypeTraitExpr>(arg))
        return "?";
    if (arg->isValueDependent())
        return "?";
    // for stuff like: OUString foo = "xxx";
    if (auto stringLiteral = dyn_cast<clang::StringLiteral>(arg))
    {
        if (stringLiteral->getCharByteWidth() == 1)
            return stringLiteral->getString();
        return "?";
    }
    // ParenListExpr containing a CXXNullPtrLiteralExpr and has a NULL type pointer
    if (auto parenListExpr = dyn_cast<ParenListExpr>(arg))
    {
        if (parenListExpr->getNumExprs() == 1)
            return getExprValue(parenListExpr->getExpr(0));
        return "?";
    }
    if (auto constructExpr = dyn_cast<CXXConstructExpr>(arg))
    {
        if (constructExpr->getNumArgs() >= 1
            && isa<clang::StringLiteral>(constructExpr->getArg(0)))
        {
            auto stringLiteral = dyn_cast<clang::StringLiteral>(constructExpr->getArg(0));
            if (stringLiteral->getCharByteWidth() == 1)
                return stringLiteral->getString();
            return "?";
        }
    }
    if (arg->getType()->isFloatingType())
    {
        APFloat x1(0.0f);
        if (arg->EvaluateAsFloat(x1, compiler.getASTContext()))
        {
            std::string s;
            llvm::raw_string_ostream os(s);
            x1.print(os);
            return os.str();
        }
    }
    APSInt x1;
    if (compat::EvaluateAsInt(arg, x1, compiler.getASTContext()))
        return x1.toString(10);
    if (isa<CXXNullPtrLiteralExpr>(arg))
        return "0";
    return "?";
}

loplugin::Plugin::Registration< SingleValFields > X("singlevalfields", false);

}

/* vim:set shiftwidth=4 softtabstop=4 expandtab: */