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
|
//===--- MagicNumbersCheck.cpp - clang-tidy-------------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// A checker for magic numbers: integer or floating point literals embedded
// in the code, outside the definition of a constant or an enumeration.
//
//===----------------------------------------------------------------------===//
#include "MagicNumbersCheck.h"
#include "../utils/OptionsUtils.h"
#include "clang/AST/ASTContext.h"
#include "clang/ASTMatchers/ASTMatchFinder.h"
#include "llvm/ADT/STLExtras.h"
#include <algorithm>
using namespace clang::ast_matchers;
namespace clang {
static bool isUsedToInitializeAConstant(const MatchFinder::MatchResult &Result,
const DynTypedNode &Node) {
const auto *AsDecl = Node.get<DeclaratorDecl>();
if (AsDecl) {
if (AsDecl->getType().isConstQualified())
return true;
return AsDecl->isImplicit();
}
if (Node.get<EnumConstantDecl>())
return true;
return llvm::any_of(Result.Context->getParents(Node),
[&Result](const DynTypedNode &Parent) {
return isUsedToInitializeAConstant(Result, Parent);
});
}
static bool isUsedToDefineABitField(const MatchFinder::MatchResult &Result,
const DynTypedNode &Node) {
const auto *AsFieldDecl = Node.get<FieldDecl>();
if (AsFieldDecl && AsFieldDecl->isBitField())
return true;
return llvm::any_of(Result.Context->getParents(Node),
[&Result](const DynTypedNode &Parent) {
return isUsedToDefineABitField(Result, Parent);
});
}
namespace tidy::readability {
const char DefaultIgnoredIntegerValues[] = "1;2;3;4;";
const char DefaultIgnoredFloatingPointValues[] = "1.0;100.0;";
MagicNumbersCheck::MagicNumbersCheck(StringRef Name, ClangTidyContext *Context)
: ClangTidyCheck(Name, Context),
IgnoreAllFloatingPointValues(
Options.get("IgnoreAllFloatingPointValues", false)),
IgnoreBitFieldsWidths(Options.get("IgnoreBitFieldsWidths", true)),
IgnorePowersOf2IntegerValues(
Options.get("IgnorePowersOf2IntegerValues", false)),
RawIgnoredIntegerValues(
Options.get("IgnoredIntegerValues", DefaultIgnoredIntegerValues)),
RawIgnoredFloatingPointValues(Options.get(
"IgnoredFloatingPointValues", DefaultIgnoredFloatingPointValues)) {
// Process the set of ignored integer values.
const std::vector<StringRef> IgnoredIntegerValuesInput =
utils::options::parseStringList(RawIgnoredIntegerValues);
IgnoredIntegerValues.resize(IgnoredIntegerValuesInput.size());
llvm::transform(IgnoredIntegerValuesInput, IgnoredIntegerValues.begin(),
[](StringRef Value) {
int64_t Res;
Value.getAsInteger(10, Res);
return Res;
});
llvm::sort(IgnoredIntegerValues);
if (!IgnoreAllFloatingPointValues) {
// Process the set of ignored floating point values.
const std::vector<StringRef> IgnoredFloatingPointValuesInput =
utils::options::parseStringList(RawIgnoredFloatingPointValues);
IgnoredFloatingPointValues.reserve(IgnoredFloatingPointValuesInput.size());
IgnoredDoublePointValues.reserve(IgnoredFloatingPointValuesInput.size());
for (const auto &InputValue : IgnoredFloatingPointValuesInput) {
llvm::APFloat FloatValue(llvm::APFloat::IEEEsingle());
auto StatusOrErr =
FloatValue.convertFromString(InputValue, DefaultRoundingMode);
assert(StatusOrErr && "Invalid floating point representation");
consumeError(StatusOrErr.takeError());
IgnoredFloatingPointValues.push_back(FloatValue.convertToFloat());
llvm::APFloat DoubleValue(llvm::APFloat::IEEEdouble());
StatusOrErr =
DoubleValue.convertFromString(InputValue, DefaultRoundingMode);
assert(StatusOrErr && "Invalid floating point representation");
consumeError(StatusOrErr.takeError());
IgnoredDoublePointValues.push_back(DoubleValue.convertToDouble());
}
llvm::sort(IgnoredFloatingPointValues);
llvm::sort(IgnoredDoublePointValues);
}
}
void MagicNumbersCheck::storeOptions(ClangTidyOptions::OptionMap &Opts) {
Options.store(Opts, "IgnoreAllFloatingPointValues",
IgnoreAllFloatingPointValues);
Options.store(Opts, "IgnoreBitFieldsWidths", IgnoreBitFieldsWidths);
Options.store(Opts, "IgnorePowersOf2IntegerValues",
IgnorePowersOf2IntegerValues);
Options.store(Opts, "IgnoredIntegerValues", RawIgnoredIntegerValues);
Options.store(Opts, "IgnoredFloatingPointValues",
RawIgnoredFloatingPointValues);
}
void MagicNumbersCheck::registerMatchers(MatchFinder *Finder) {
Finder->addMatcher(integerLiteral().bind("integer"), this);
if (!IgnoreAllFloatingPointValues)
Finder->addMatcher(floatLiteral().bind("float"), this);
}
void MagicNumbersCheck::check(const MatchFinder::MatchResult &Result) {
TraversalKindScope RAII(*Result.Context, TK_AsIs);
checkBoundMatch<IntegerLiteral>(Result, "integer");
checkBoundMatch<FloatingLiteral>(Result, "float");
}
bool MagicNumbersCheck::isConstant(const MatchFinder::MatchResult &Result,
const Expr &ExprResult) const {
return llvm::any_of(
Result.Context->getParents(ExprResult),
[&Result](const DynTypedNode &Parent) {
if (isUsedToInitializeAConstant(Result, Parent))
return true;
// Ignore this instance, because this matches an
// expanded class enumeration value.
if (Parent.get<CStyleCastExpr>() &&
llvm::any_of(
Result.Context->getParents(Parent),
[](const DynTypedNode &GrandParent) {
return GrandParent.get<SubstNonTypeTemplateParmExpr>() !=
nullptr;
}))
return true;
// Ignore this instance, because this match reports the
// location where the template is defined, not where it
// is instantiated.
if (Parent.get<SubstNonTypeTemplateParmExpr>())
return true;
// Don't warn on string user defined literals:
// std::string s = "Hello World"s;
if (const auto *UDL = Parent.get<UserDefinedLiteral>())
if (UDL->getLiteralOperatorKind() == UserDefinedLiteral::LOK_String)
return true;
return false;
});
}
bool MagicNumbersCheck::isIgnoredValue(const IntegerLiteral *Literal) const {
const llvm::APInt IntValue = Literal->getValue();
const int64_t Value = IntValue.getZExtValue();
if (Value == 0)
return true;
if (IgnorePowersOf2IntegerValues && IntValue.isPowerOf2())
return true;
return std::binary_search(IgnoredIntegerValues.begin(),
IgnoredIntegerValues.end(), Value);
}
bool MagicNumbersCheck::isIgnoredValue(const FloatingLiteral *Literal) const {
const llvm::APFloat FloatValue = Literal->getValue();
if (FloatValue.isZero())
return true;
if (&FloatValue.getSemantics() == &llvm::APFloat::IEEEsingle()) {
const float Value = FloatValue.convertToFloat();
return std::binary_search(IgnoredFloatingPointValues.begin(),
IgnoredFloatingPointValues.end(), Value);
}
if (&FloatValue.getSemantics() == &llvm::APFloat::IEEEdouble()) {
const double Value = FloatValue.convertToDouble();
return std::binary_search(IgnoredDoublePointValues.begin(),
IgnoredDoublePointValues.end(), Value);
}
return false;
}
bool MagicNumbersCheck::isSyntheticValue(const SourceManager *SourceManager,
const IntegerLiteral *Literal) const {
const std::pair<FileID, unsigned> FileOffset =
SourceManager->getDecomposedLoc(Literal->getLocation());
if (FileOffset.first.isInvalid())
return false;
const StringRef BufferIdentifier =
SourceManager->getBufferOrFake(FileOffset.first).getBufferIdentifier();
return BufferIdentifier.empty();
}
bool MagicNumbersCheck::isBitFieldWidth(
const clang::ast_matchers::MatchFinder::MatchResult &Result,
const IntegerLiteral &Literal) const {
return IgnoreBitFieldsWidths &&
llvm::any_of(Result.Context->getParents(Literal),
[&Result](const DynTypedNode &Parent) {
return isUsedToDefineABitField(Result, Parent);
});
}
} // namespace tidy::readability
} // namespace clang
|
