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
/* -*- 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 <unordered_map>


#include "clang/AST/Attr.h"

#include "plugin.hxx"
#include "compat.hxx"

/**
This plugin performs 3 different analyses:

(1) Find unused methods
(2) Find methods whose return types are never evaluated
(3) Find methods which are public, but are never called from outside the class i.e. they can be private

It does so, by dumping various call/definition/use info to a log file.
Then we will post-process the various lists and find the set of unused methods.

Be warned that it produces around 15G of log file.

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

and then
  $ for dir in *; do make FORCE_COMPILE_ALL=1 UPDATE_FILES=$dir COMPILER_PLUGIN_TOOL='unusedmethodsremove' $dir; done
to auto-remove the method declarations

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

*/

namespace {

struct MyFuncInfo
{
    std::string access;
    std::string returnType;
    std::string nameAndParams;
    std::string sourceLocation;
    std::string virtualness;

};
bool operator < (const MyFuncInfo &lhs, const MyFuncInfo &rhs)
{
    return std::tie(lhs.returnType, lhs.nameAndParams)
         < std::tie(rhs.returnType, rhs.nameAndParams);
}

// try to limit the voluminous output a little

// for the "unused method" analysis
static std::set<MyFuncInfo> callSet;
static std::set<MyFuncInfo> definitionSet;
// for the "unused return type" analysis
static std::set<MyFuncInfo> usedReturnSet;
// for the "can be private" analysis
static std::set<MyFuncInfo> calledFromOutsideSet;


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

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

        // 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 MyFuncInfo & s : definitionSet)
            output += "definition:\t" + s.access + "\t" + s.returnType + "\t" + s.nameAndParams<--- Consider using std::accumulate algorithm instead of a raw loop.
                      + "\t" + s.sourceLocation + "\t" + s.virtualness + "\n";
        // for the "unused method" analysis
        for (const MyFuncInfo & s : callSet)
            output += "call:\t" + s.returnType + "\t" + s.nameAndParams + "\n";<--- Consider using std::accumulate algorithm instead of a raw loop.
        // for the "unused return type" analysis
        for (const MyFuncInfo & s : usedReturnSet)
            output += "usedReturn:\t" + s.returnType + "\t" + s.nameAndParams + "\n";<--- Consider using std::accumulate algorithm instead of a raw loop.
        // for the "method can be private" analysis
        for (const MyFuncInfo & s : calledFromOutsideSet)
            output += "outside:\t" + s.returnType + "\t" + s.nameAndParams + "\n";<--- Consider using std::accumulate algorithm instead of a raw loop.
        std::ofstream myfile;
        myfile.open( WORKDIR "/loplugin.unusedmethods.log", std::ios::app | std::ios::out);
        myfile << output;
        myfile.close();
    }

    bool shouldVisitTemplateInstantiations () const { return true; }
    bool shouldVisitImplicitCode() const { return true; }

    bool VisitCallExpr(CallExpr* );
    bool VisitFunctionDecl( const FunctionDecl* decl );
    bool VisitDeclRefExpr( const DeclRefExpr* );
    bool VisitCXXConstructExpr( const CXXConstructExpr* );
    bool TraverseCXXRecordDecl( CXXRecordDecl* );
    bool TraverseFunctionDecl( FunctionDecl* );
    bool TraverseCXXMethodDecl( CXXMethodDecl* );
    bool TraverseCXXConversionDecl( CXXConversionDecl* );
#if CLANG_VERSION >= 50000
    bool TraverseCXXDeductionGuideDecl( CXXDeductionGuideDecl* );
#endif
private:
    void logCallToRootMethods(const FunctionDecl* functionDecl, std::set<MyFuncInfo>& funcSet);
    MyFuncInfo niceName(const FunctionDecl* functionDecl);
    std::string toString(SourceLocation loc);
    void functionTouchedFromExpr( const FunctionDecl* calleeFunctionDecl, const Expr* expr );
    CXXRecordDecl const * currentCxxRecordDecl = nullptr;
    FunctionDecl const * currentFunctionDecl = nullptr;
};

MyFuncInfo UnusedMethods::niceName(const FunctionDecl* functionDecl)
{
    if (functionDecl->getInstantiatedFromMemberFunction())
        functionDecl = functionDecl->getInstantiatedFromMemberFunction();
    else if (functionDecl->getClassScopeSpecializationPattern())
        functionDecl = functionDecl->getClassScopeSpecializationPattern();
    else if (functionDecl->getTemplateInstantiationPattern())
        functionDecl = functionDecl->getTemplateInstantiationPattern();

    MyFuncInfo aInfo;
    switch (functionDecl->getAccess())
    {
    case AS_public: aInfo.access = "public"; break;
    case AS_private: aInfo.access = "private"; break;
    case AS_protected: aInfo.access = "protected"; break;
    default: aInfo.access = "unknown"; break;
    }
    if (!isa<CXXConstructorDecl>(functionDecl)) {
        aInfo.returnType = functionDecl->getReturnType().getCanonicalType().getAsString();
    } else {
        aInfo.returnType = "";
    }

    if (auto methodDecl = dyn_cast<CXXMethodDecl>(functionDecl)) {
        const CXXRecordDecl* recordDecl = methodDecl->getParent();
        aInfo.nameAndParams = recordDecl->getQualifiedNameAsString()
                + "::"
                + functionDecl->getNameAsString()
                + "(";
        if (methodDecl->isVirtual())
            aInfo.virtualness = "virtual";
    }
    else
    {
        aInfo.nameAndParams = functionDecl->getQualifiedNameAsString() + "(";
    }
    bool bFirst = true;
    for (const ParmVarDecl *pParmVarDecl : compat::parameters(*functionDecl)) {
        if (bFirst)
            bFirst = false;
        else
            aInfo.nameAndParams += ",";
        aInfo.nameAndParams += pParmVarDecl->getType().getCanonicalType().getAsString();
    }
    aInfo.nameAndParams += ")";
    if (isa<CXXMethodDecl>(functionDecl) && dyn_cast<CXXMethodDecl>(functionDecl)->isConst()) {
        aInfo.nameAndParams += " const";
    }

    aInfo.sourceLocation = toString( functionDecl->getLocation() );

    return aInfo;
}

std::string UnusedMethods::toString(SourceLocation loc)
{
    SourceLocation expansionLoc = compiler.getSourceManager().getExpansionLoc( loc );
    StringRef name = compiler.getSourceManager().getFilename(expansionLoc);
    std::string sourceLocation = std::string(name.substr(strlen(SRCDIR)+1)) + ":" + std::to_string(compiler.getSourceManager().getSpellingLineNumber(expansionLoc));
    loplugin::normalizeDotDotInFilePath(sourceLocation);
    return sourceLocation;
}

// For virtual/overriding methods, we need to pretend we called the root method(s),
// so that they get marked as used.
void UnusedMethods::logCallToRootMethods(const FunctionDecl* functionDecl, std::set<MyFuncInfo>& funcSet)
{
    functionDecl = functionDecl->getCanonicalDecl();
    bool bCalledSuperMethod = false;
    if (isa<CXXMethodDecl>(functionDecl)) {
        const CXXMethodDecl* methodDecl = dyn_cast<CXXMethodDecl>(functionDecl);
        for(CXXMethodDecl::method_iterator it = methodDecl->begin_overridden_methods();
            it != methodDecl->end_overridden_methods(); ++it)
        {
            logCallToRootMethods(*it, funcSet);
            bCalledSuperMethod = true;
        }
    }
    if (!bCalledSuperMethod)
    {
        while (functionDecl->getTemplateInstantiationPattern())
            functionDecl = functionDecl->getTemplateInstantiationPattern();
        if (functionDecl->getLocation().isValid() && !ignoreLocation( functionDecl )
             && !functionDecl->isExternC())
            funcSet.insert(niceName(functionDecl));
    }
}

bool UnusedMethods::VisitCallExpr(CallExpr* expr)
{
    // Note that I don't ignore ANYTHING here, because I want to get calls to my code that result
    // from template instantiation deep inside the STL and other external code

    FunctionDecl* calleeFunctionDecl = expr->getDirectCallee();
    if (calleeFunctionDecl == nullptr) {
        Expr* callee = expr->getCallee()->IgnoreParenImpCasts();
        DeclRefExpr* dr = dyn_cast<DeclRefExpr>(callee);
        if (dr) {
            calleeFunctionDecl = dyn_cast<FunctionDecl>(dr->getDecl());
            if (calleeFunctionDecl)
                goto gotfunc;
        }
        return true;
    }

gotfunc:


    if (currentFunctionDecl == calleeFunctionDecl)
        ; // for "unused method" analysis, ignore recursive calls
    else if (currentFunctionDecl
            && currentFunctionDecl->getIdentifier()
            && currentFunctionDecl->getName() == "Clone"
            && currentFunctionDecl->getParent() == calleeFunctionDecl->getParent()
            && isa<CXXConstructorDecl>(calleeFunctionDecl))
        ; // if we are inside Clone(), ignore calls to the same class's constructor
    else
        logCallToRootMethods(calleeFunctionDecl, callSet);

    const Stmt* parent = getParentStmt(expr);

    // Now do the checks necessary for the "can be private" analysis
    CXXMethodDecl* calleeMethodDecl = dyn_cast<CXXMethodDecl>(calleeFunctionDecl);
    if (calleeMethodDecl && calleeMethodDecl->getAccess() != AS_private)
    {
        const FunctionDecl* parentFunctionOfCallSite = getParentFunctionDecl(expr);
        if (parentFunctionOfCallSite != calleeFunctionDecl) {
            if (!parentFunctionOfCallSite || !ignoreLocation(parentFunctionOfCallSite)) {
                calledFromOutsideSet.insert(niceName(calleeFunctionDecl));
            }
        }
    }

    // Now do the checks necessary for the "unused return value" analysis
    if (calleeFunctionDecl->getReturnType()->isVoidType()) {
        return true;
    }
    if (!parent) {
        // we will get null parent if it's under a CXXConstructExpr node
        logCallToRootMethods(calleeFunctionDecl, usedReturnSet);
        return true;
    }
    if (isa<Expr>(parent) || isa<ReturnStmt>(parent) || isa<DeclStmt>(parent)
        || isa<IfStmt>(parent) || isa<SwitchStmt>(parent) || isa<ForStmt>(parent)
        || isa<WhileStmt>(parent) || isa<DoStmt>(parent)
        || isa<CXXForRangeStmt>(parent))
    {
        logCallToRootMethods(calleeFunctionDecl, usedReturnSet);
        return true;
    }
    if (isa<CompoundStmt>(parent) || isa<DefaultStmt>(parent) || isa<CaseStmt>(parent)
        || isa<LabelStmt>(parent))
    {
        return true;
    }
    parent->dump();
    return true;
}

bool UnusedMethods::VisitCXXConstructExpr( const CXXConstructExpr* constructExpr )
{
    // Note that I don't ignore ANYTHING here, because I want to get calls to my code that result
    // from template instantiation deep inside the STL and other external code

    const CXXConstructorDecl* constructorDecl = constructExpr->getConstructor();
    constructorDecl = constructorDecl->getCanonicalDecl();

    if (!constructorDecl->getLocation().isValid() || ignoreLocation(constructorDecl)) {
        return true;
    }

    logCallToRootMethods(constructorDecl, callSet);

    // Now do the checks necessary for the "can be private" analysis
    if (constructorDecl->getParent() != currentCxxRecordDecl)
        calledFromOutsideSet.insert(niceName(constructorDecl));

    return true;
}

bool UnusedMethods::VisitFunctionDecl( const FunctionDecl* functionDecl )
{
    // ignore stuff that forms part of the stable URE interface
    if (isInUnoIncludeFile(functionDecl)) {
        return true;
    }
    const FunctionDecl* canonicalFunctionDecl = functionDecl->getCanonicalDecl();
    if (isa<CXXDestructorDecl>(functionDecl)) {
        return true;
    }
    if (functionDecl->isDeleted() || functionDecl->isDefaulted()) {
        return true;
    }
    if (isa<CXXConstructorDecl>(functionDecl)
        && dyn_cast<CXXConstructorDecl>(functionDecl)->isCopyOrMoveConstructor())
    {
        return true;
    }
    if (!canonicalFunctionDecl->getLocation().isValid() || ignoreLocation(canonicalFunctionDecl)) {
        return true;
    }
    // ignore method overrides, since the call will show up as being directed to the root method
    const CXXMethodDecl* methodDecl = dyn_cast<CXXMethodDecl>(functionDecl);
    if (methodDecl && (methodDecl->size_overridden_methods() != 0 || methodDecl->hasAttr<OverrideAttr>())) {
        return true;
    }
    if (!functionDecl->isExternC()) {
        MyFuncInfo funcInfo = niceName(canonicalFunctionDecl);
        definitionSet.insert(funcInfo);
    }
    return true;
}

bool UnusedMethods::VisitDeclRefExpr( const DeclRefExpr* declRefExpr )
{
    const FunctionDecl* functionDecl = dyn_cast<FunctionDecl>(declRefExpr->getDecl());
    if (!functionDecl) {
        return true;
    }
    logCallToRootMethods(functionDecl->getCanonicalDecl(), callSet);
    logCallToRootMethods(functionDecl->getCanonicalDecl(), usedReturnSet);

    // Now do the checks necessary for the "can be private" analysis
    const CXXMethodDecl* methodDecl = dyn_cast<CXXMethodDecl>(functionDecl);
    if (methodDecl && methodDecl->getAccess() != AS_private)
    {
        const FunctionDecl* parentFunctionOfCallSite = getParentFunctionDecl(declRefExpr);
        if (parentFunctionOfCallSite != functionDecl) {
            if (!parentFunctionOfCallSite || !ignoreLocation(parentFunctionOfCallSite)) {
                calledFromOutsideSet.insert(niceName(functionDecl));
            }
        }
    }

    return true;
}

bool UnusedMethods::TraverseCXXRecordDecl(CXXRecordDecl* cxxRecordDecl)
{
    auto copy = currentCxxRecordDecl;
    currentCxxRecordDecl = cxxRecordDecl;
    bool ret = RecursiveASTVisitor::TraverseCXXRecordDecl(cxxRecordDecl);
    currentCxxRecordDecl = copy;
    return ret;
}

bool UnusedMethods::TraverseFunctionDecl(FunctionDecl* f)
{
    auto copy = currentFunctionDecl;
    currentFunctionDecl = f;
    bool ret = RecursiveASTVisitor::TraverseFunctionDecl(f);
    currentFunctionDecl = copy;
    return ret;
}
bool UnusedMethods::TraverseCXXMethodDecl(CXXMethodDecl* f)
{
    auto copy = currentFunctionDecl;
    currentFunctionDecl = f;
    bool ret = RecursiveASTVisitor::TraverseCXXMethodDecl(f);
    currentFunctionDecl = copy;
    return ret;
}
bool UnusedMethods::TraverseCXXConversionDecl(CXXConversionDecl* f)
{
    auto copy = currentFunctionDecl;
    currentFunctionDecl = f;
    bool ret = RecursiveASTVisitor::TraverseCXXConversionDecl(f);
    currentFunctionDecl = copy;
    return ret;
}
#if CLANG_VERSION >= 50000
bool UnusedMethods::TraverseCXXDeductionGuideDecl(CXXDeductionGuideDecl* f)
{
    auto copy = currentFunctionDecl;
    currentFunctionDecl = f;
    bool ret = RecursiveASTVisitor::TraverseCXXDeductionGuideDecl(f);
    currentFunctionDecl = copy;
    return ret;
}
#endif

loplugin::Plugin::Registration< UnusedMethods > X("unusedmethods", false);

}

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