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
| //===--- NonConstReferences.cpp - clang-tidy --------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "NonConstReferences.h"
#include "../utils/OptionsUtils.h"
#include "clang/AST/DeclBase.h"
#include "clang/ASTMatchers/ASTMatchFinder.h"
#include "clang/ASTMatchers/ASTMatchers.h"
using namespace clang::ast_matchers;
namespace clang {
namespace tidy {
namespace google {
namespace runtime {
NonConstReferences::NonConstReferences(StringRef Name,
ClangTidyContext *Context)
: ClangTidyCheck(Name, Context),
WhiteListTypes(
utils::options::parseStringList(Options.get("WhiteListTypes", ""))) {}
void NonConstReferences::storeOptions(ClangTidyOptions::OptionMap &Opts) {
Options.store(Opts, "WhiteListTypes",
utils::options::serializeStringList(WhiteListTypes));
}
void NonConstReferences::registerMatchers(MatchFinder *Finder) {
if (!getLangOpts().CPlusPlus)
return;
Finder->addMatcher(
parmVarDecl(
unless(isInstantiated()),
hasType(references(
qualType(unless(isConstQualified())).bind("referenced_type"))),
unless(hasType(rValueReferenceType())))
.bind("param"),
this);
}
void NonConstReferences::check(const MatchFinder::MatchResult &Result) {
const auto *Parameter = Result.Nodes.getNodeAs<ParmVarDecl>("param");
const auto *Function =
dyn_cast_or_null<FunctionDecl>(Parameter->getParentFunctionOrMethod());
if (Function == nullptr || Function->isImplicit())
return;
if (Function->getLocation().isMacroID())
return;
if (!Function->isCanonicalDecl())
return;
if (const auto *Method = dyn_cast<CXXMethodDecl>(Function)) {
// Don't warn on implementations of an interface using references.
if (Method->begin_overridden_methods() != Method->end_overridden_methods())
return;
// Don't warn on lambdas, as they frequently have to conform to the
// interface defined elsewhere.
if (Method->getParent()->isLambda())
return;
}
auto ReferencedType = *Result.Nodes.getNodeAs<QualType>("referenced_type");
if (std::find_if(WhiteListTypes.begin(), WhiteListTypes.end(),
[&](llvm::StringRef WhiteListType) {
return ReferencedType.getCanonicalType().getAsString(
Result.Context->getPrintingPolicy()) ==
WhiteListType;
}) != WhiteListTypes.end())
return;
// Don't warn on function references, they shouldn't be constant.
if (ReferencedType->isFunctionProtoType())
return;
// Don't warn on dependent types in templates.
if (ReferencedType->isDependentType())
return;
if (Function->isOverloadedOperator()) {
switch (Function->getOverloadedOperator()) {
case clang::OO_LessLess:
case clang::OO_PlusPlus:
case clang::OO_MinusMinus:
case clang::OO_PlusEqual:
case clang::OO_MinusEqual:
case clang::OO_StarEqual:
case clang::OO_SlashEqual:
case clang::OO_PercentEqual:
case clang::OO_LessLessEqual:
case clang::OO_GreaterGreaterEqual:
case clang::OO_PipeEqual:
case clang::OO_CaretEqual:
case clang::OO_AmpEqual:
// Don't warn on the first parameter of operator<<(Stream&, ...),
// operator++, operator-- and operation+assignment operators.
if (Function->getParamDecl(0) == Parameter)
return;
break;
case clang::OO_GreaterGreater: {
auto isNonConstRef = [](clang::QualType T) {
return T->isReferenceType() &&
!T.getNonReferenceType().isConstQualified();
};
// Don't warn on parameters of stream extractors:
// Stream& operator>>(Stream&, Value&);
// Both parameters should be non-const references by convention.
if (isNonConstRef(Function->getParamDecl(0)->getType()) &&
(Function->getNumParams() < 2 || // E.g. member operator>>.
isNonConstRef(Function->getParamDecl(1)->getType())) &&
isNonConstRef(Function->getReturnType()))
return;
break;
}
default:
break;
}
}
// Some functions use references to comply with established standards.
if (Function->getDeclName().isIdentifier() && Function->getName() == "swap")
return;
// iostream parameters are typically passed by non-const reference.
if (StringRef(ReferencedType.getAsString()).endswith("stream"))
return;
if (Parameter->getName().empty()) {
diag(Parameter->getLocation(), "non-const reference parameter at index %0, "
"make it const or use a pointer")
<< Parameter->getFunctionScopeIndex();
} else {
diag(Parameter->getLocation(),
"non-const reference parameter %0, make it const or use a pointer")
<< Parameter;
}
}
} // namespace runtime
} // namespace google
} // namespace tidy
} // namespace clang
|