summaryrefslogtreecommitdiffstats
path: root/compilerplugins/clang/noexceptmove.cxx
blob: b2679024e97bc8330eac82b2c11df3894e35fee0 (plain)
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
/* -*- 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/.
 */
// versions before 9.0 didn't have getExceptionSpecType

#include "plugin.hxx"

// clang before V9 does not have API to report exception spec type
#if CLANG_VERSION >= 90000

#include "check.hxx"

#include <string>
#include <set>

/**
  Look for move constructors that can be noexcept.
*/

namespace
{
/// Look for the stuff that can be marked noexcept, but only if we also mark some of the callees noexcept.
/// Off by default so as not too annoy people.
constexpr bool bLookForStuffWeCanFix = false;

class NoExceptMove : public loplugin::FilteringPlugin<NoExceptMove>
{
public:
    explicit NoExceptMove(loplugin::InstantiationData const& data)
        : FilteringPlugin(data)
    {
    }

    virtual void run() override
    {
        StringRef fn(handler.getMainFileName());
        // ONDXPagePtr::operator= calls ONDXPage::ReleaseRef which cannot be noexcept
        if (loplugin::isSamePathname(fn,
                                     SRCDIR "/connectivity/source/drivers/dbase/dindexnode.cxx"))
            return;
        TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
    }

    bool shouldVisitImplicitCode() const { return true; }

    bool TraverseCXXConstructorDecl(CXXConstructorDecl*);
    bool TraverseCXXMethodDecl(CXXMethodDecl*);
    bool VisitCallExpr(const CallExpr*);
    bool VisitCXXConstructExpr(const CXXConstructExpr*);
    bool VisitVarDecl(const VarDecl*);

private:
    llvm::Optional<bool> IsCallThrows(const CallExpr* callExpr);
    std::vector<bool> m_ConstructorThrows;
    std::vector<std::vector<const Decl*>> m_Exclusions;
    std::vector<bool> m_CannotFix;
};

bool NoExceptMove::TraverseCXXConstructorDecl(CXXConstructorDecl* constructorDecl)
{
    const bool isMove = constructorDecl->isMoveConstructor()
                        && constructorDecl->getExceptionSpecType() == EST_None
                        && !constructorDecl->isDefaulted() && !constructorDecl->isDeleted()
                        && !ignoreLocation(constructorDecl)
                        && constructorDecl->isThisDeclarationADefinition()
                        && constructorDecl->getBody() != nullptr;
    if (isMove)
    {
        m_ConstructorThrows.push_back(false);
        m_Exclusions.emplace_back();
        m_CannotFix.push_back(false);
    }
    bool rv = RecursiveASTVisitor::TraverseCXXConstructorDecl(constructorDecl);
    if (isMove)
    {
        if (!m_ConstructorThrows.back())
        {
            report(DiagnosticsEngine::Warning, "move constructor can be noexcept",
                   constructorDecl->getSourceRange().getBegin())
                << constructorDecl->getSourceRange();
            auto canonicalDecl = constructorDecl->getCanonicalDecl();
            if (canonicalDecl != constructorDecl)
                report(DiagnosticsEngine::Note, "declaration here",
                       canonicalDecl->getSourceRange().getBegin())
                    << canonicalDecl->getSourceRange();
        }
        else if (bLookForStuffWeCanFix && !m_CannotFix.back())
        {
            report(DiagnosticsEngine::Warning, "move constructor can be noexcept",
                   constructorDecl->getSourceRange().getBegin())
                << constructorDecl->getSourceRange();
            auto canonicalDecl = constructorDecl->getCanonicalDecl();
            if (canonicalDecl != constructorDecl)
                report(DiagnosticsEngine::Note, "declaration here",
                       canonicalDecl->getSourceRange().getBegin())
                    << canonicalDecl->getSourceRange();
            for (const Decl* callDecl : m_Exclusions.back())
                report(DiagnosticsEngine::Warning, "but need to fix this to be noexcept",
                       callDecl->getSourceRange().getBegin())
                    << callDecl->getSourceRange();
        }
        m_ConstructorThrows.pop_back();
        m_Exclusions.pop_back();
        m_CannotFix.pop_back();
    }
    return rv;
}

bool NoExceptMove::TraverseCXXMethodDecl(CXXMethodDecl* methodDecl)
{
    bool isMove = methodDecl->isMoveAssignmentOperator()
                  && methodDecl->getExceptionSpecType() == EST_None && !methodDecl->isDefaulted()
                  && !methodDecl->isDeleted() && !ignoreLocation(methodDecl)
                  && methodDecl->isThisDeclarationADefinition() && methodDecl->getBody() != nullptr;
    if (isMove)
    {
        StringRef fn = getFilenameOfLocation(
            compiler.getSourceManager().getSpellingLoc(compat::getBeginLoc(methodDecl)));
        // SfxObjectShellLock::operator= calls SotObject::OwnerLock which in turn calls stuff which cannot be noexcept
        if (loplugin::isSamePathname(fn, SRCDIR "/include/sfx2/objsh.hxx"))
            isMove = false;
    }
    if (isMove)
    {
        m_ConstructorThrows.push_back(false);
        m_Exclusions.emplace_back();
        m_CannotFix.push_back(false);
    }
    bool rv = RecursiveASTVisitor::TraverseCXXMethodDecl(methodDecl);
    if (isMove)
    {
        if (!m_ConstructorThrows.back())
        {
            report(DiagnosticsEngine::Warning, "move operator= can be noexcept",
                   methodDecl->getSourceRange().getBegin())
                << methodDecl->getSourceRange();
            auto canonicalDecl = methodDecl->getCanonicalDecl();
            if (canonicalDecl != methodDecl)
                report(DiagnosticsEngine::Note, "declaration here",
                       canonicalDecl->getSourceRange().getBegin())
                    << canonicalDecl->getSourceRange();
        }
        else if (bLookForStuffWeCanFix && !m_CannotFix.back())
        {
            report(DiagnosticsEngine::Warning, "move operator= can be noexcept",
                   methodDecl->getSourceRange().getBegin())
                << methodDecl->getSourceRange();
            auto canonicalDecl = methodDecl->getCanonicalDecl();
            if (canonicalDecl != methodDecl)
                report(DiagnosticsEngine::Note, "declaration here",
                       canonicalDecl->getSourceRange().getBegin())
                    << canonicalDecl->getSourceRange();
            for (const Decl* callDecl : m_Exclusions.back())
                report(DiagnosticsEngine::Warning, "but need to fix this to be noexcept",
                       callDecl->getSourceRange().getBegin())
                    << callDecl->getSourceRange();
        }
        m_ConstructorThrows.pop_back();
        m_Exclusions.pop_back();
        m_CannotFix.pop_back();
    }
    return rv;
}

bool NoExceptMove::VisitCallExpr(const CallExpr* callExpr)
{
    if (ignoreLocation(callExpr))
        return true;
    if (m_ConstructorThrows.empty())
        return true;
    llvm::Optional<bool> bCallThrows = IsCallThrows(callExpr);
    if (!bCallThrows)
    {
        callExpr->dump();
        if (callExpr->getCalleeDecl())
            callExpr->getCalleeDecl()->dump();
        report(DiagnosticsEngine::Warning, "what's up doc?", callExpr->getSourceRange().getBegin())
            << callExpr->getSourceRange();
        m_ConstructorThrows.back() = true;
        return true;
    }
    if (*bCallThrows)
        m_ConstructorThrows.back() = true;
    return true;
}

static bool IsCallThrowsSpec(clang::ExceptionSpecificationType est)
{
    return !(est == EST_DynamicNone || est == EST_NoThrow || est == EST_BasicNoexcept
             || est == EST_NoexceptTrue);
}

bool NoExceptMove::VisitCXXConstructExpr(const CXXConstructExpr* constructExpr)
{
    if (ignoreLocation(constructExpr))
        return true;
    if (m_ConstructorThrows.empty())
        return true;
    auto constructorDecl = constructExpr->getConstructor();
    auto est = constructorDecl->getExceptionSpecType();
    if (constructorDecl->isDefaulted() && est == EST_None)
        ; // ok, non-throwing
    else if (IsCallThrowsSpec(est))
    {
        if (bLookForStuffWeCanFix)
        {
            if (est == EST_None && !ignoreLocation(constructorDecl))
                m_Exclusions.back().push_back(constructorDecl);
            else
                m_CannotFix.back() = true;
        }
        m_ConstructorThrows.back() = true;
    }
    return true;
}

bool NoExceptMove::VisitVarDecl(const VarDecl* varDecl)
{
    if (varDecl->getLocation().isValid() && ignoreLocation(varDecl))
        return true;
    if (m_ConstructorThrows.empty())
        return true;
    // The clang AST does not show me implicit calls to destructors at the end of a block,
    // so assume any local var decls of class type will call their destructor.
    if (!varDecl->getType()->isRecordType())
        return true;
    auto cxxRecordDecl = varDecl->getType()->getAsCXXRecordDecl();
    if (!cxxRecordDecl)
        return true;
    auto destructorDecl = cxxRecordDecl->getDestructor();
    if (!destructorDecl)
        return true;
    auto est = destructorDecl->getExceptionSpecType();
    if (destructorDecl->isDefaulted() && est == EST_None)
        ; // ok, non-throwing
    else if (IsCallThrowsSpec(est))
    {
        if (bLookForStuffWeCanFix)
        {
            if (est == EST_None && !ignoreLocation(destructorDecl))
                m_Exclusions.back().push_back(destructorDecl);
            else
                m_CannotFix.back() = true;
        }
        m_ConstructorThrows.back() = true;
    }
    return true;
}

llvm::Optional<bool> NoExceptMove::IsCallThrows(const CallExpr* callExpr)
{
    const FunctionDecl* calleeFunctionDecl = callExpr->getDirectCallee();
    if (calleeFunctionDecl)
    {
        auto est = calleeFunctionDecl->getExceptionSpecType();
        if (bLookForStuffWeCanFix)
        {
            if (est == EST_None && !ignoreLocation(calleeFunctionDecl))
                m_Exclusions.back().push_back(calleeFunctionDecl);
            else
                m_CannotFix.back() = true;
        }
        // Whitelist of functions that could be noexcept, but we can't change them because of backwards-compatibility reasons
        // css::uno::XInterface::acquire
        // css::uno::XInterface::release
        if (calleeFunctionDecl->getIdentifier())
        {
            auto name = calleeFunctionDecl->getName();
            if (auto cxxMethodDecl = dyn_cast<CXXMethodDecl>(calleeFunctionDecl))
                if (loplugin::ContextCheck(cxxMethodDecl->getParent()->getDeclContext())
                        .Namespace("uno")
                        .Namespace("star")
                        .Namespace("sun")
                        .Namespace("com")
                        .GlobalNamespace()
                    && (name == "acquire" || name == "release"))
                    return false;
            if (name == "osl_releasePipe" || name == "osl_destroySocketAddr")
                return false;
        }
        return IsCallThrowsSpec(est);
    }

    auto calleeExpr = callExpr->getCallee();
    if (isa<CXXDependentScopeMemberExpr>(calleeExpr) || isa<UnresolvedLookupExpr>(calleeExpr))
    {
        m_CannotFix.back() = true;
        return true;
    }

    // check for call via function-pointer
    clang::QualType calleeType;
    if (auto fieldDecl = dyn_cast_or_null<FieldDecl>(callExpr->getCalleeDecl()))
        calleeType = fieldDecl->getType();
    else if (auto varDecl = dyn_cast_or_null<VarDecl>(callExpr->getCalleeDecl()))
        calleeType = varDecl->getType();
    else
    {
        m_CannotFix.back() = true;
        return llvm::Optional<bool>();
    }

    // whitelist of functions that could be noexcept, but we can't change them because of backwards-compatibility reasons
    if (auto typedefType = calleeType->getAs<TypedefType>())
        if (typedefType->getDecl()->getName() == "uno_ReleaseMappingFunc")
            return false;

    if (calleeType->isPointerType())
        calleeType = calleeType->getPointeeType();
    auto funcProto = calleeType->getAs<FunctionProtoType>();
    if (!funcProto)
    {
        m_CannotFix.back() = true;
        return llvm::Optional<bool>();
    }

    auto est = funcProto->getExceptionSpecType();
    if (bLookForStuffWeCanFix)
    {
        m_CannotFix.back() = true; // TODO, could improve
    }
    return IsCallThrowsSpec(est);
}

loplugin::Plugin::Registration<NoExceptMove> noexceptmove("noexceptmove");
}

#endif // CLANG_VERSION
/* vim:set shiftwidth=4 softtabstop=4 expandtab: */