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
|
//===- RedundantStringInitCheck.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 "RedundantStringInitCheck.h"
#include "../utils/Matchers.h"
#include "../utils/OptionsUtils.h"
#include "clang/ASTMatchers/ASTMatchers.h"
using namespace clang::ast_matchers;
using namespace clang::tidy::matchers;
namespace clang {
namespace tidy {
namespace readability {
const char DefaultStringNames[] =
"::std::basic_string_view;::std::basic_string";
static ast_matchers::internal::Matcher<NamedDecl>
hasAnyNameStdString(std::vector<std::string> Names) {
return ast_matchers::internal::Matcher<NamedDecl>(
new ast_matchers::internal::HasNameMatcher(std::move(Names)));
}
static std::vector<std::string>
removeNamespaces(const std::vector<std::string> &Names) {
std::vector<std::string> Result;
Result.reserve(Names.size());
for (const std::string &Name : Names) {
std::string::size_type ColonPos = Name.rfind(':');
Result.push_back(
Name.substr(ColonPos == std::string::npos ? 0 : ColonPos + 1));
}
return Result;
}
static const CXXConstructExpr *
getConstructExpr(const CXXCtorInitializer &CtorInit) {
const Expr *InitExpr = CtorInit.getInit();
if (const auto *CleanUpExpr = dyn_cast<ExprWithCleanups>(InitExpr))
InitExpr = CleanUpExpr->getSubExpr();
return dyn_cast<CXXConstructExpr>(InitExpr);
}
static llvm::Optional<SourceRange>
getConstructExprArgRange(const CXXConstructExpr &Construct) {
SourceLocation B, E;
for (const Expr *Arg : Construct.arguments()) {
if (B.isInvalid())
B = Arg->getBeginLoc();
if (Arg->getEndLoc().isValid())
E = Arg->getEndLoc();
}
if (B.isInvalid() || E.isInvalid())
return llvm::None;
return SourceRange(B, E);
}
RedundantStringInitCheck::RedundantStringInitCheck(StringRef Name,
ClangTidyContext *Context)
: ClangTidyCheck(Name, Context),
StringNames(utils::options::parseStringList(
Options.get("StringNames", DefaultStringNames))) {}
void RedundantStringInitCheck::storeOptions(ClangTidyOptions::OptionMap &Opts) {
Options.store(Opts, "StringNames", DefaultStringNames);
}
void RedundantStringInitCheck::registerMatchers(MatchFinder *Finder) {
const auto HasStringTypeName = hasAnyNameStdString(StringNames);
const auto HasStringCtorName =
hasAnyNameStdString(removeNamespaces(StringNames));
// Match string constructor.
const auto StringConstructorExpr = expr(
anyOf(cxxConstructExpr(argumentCountIs(1),
hasDeclaration(cxxMethodDecl(HasStringCtorName))),
// If present, the second argument is the alloc object which must
// not be present explicitly.
cxxConstructExpr(argumentCountIs(2),
hasDeclaration(cxxMethodDecl(HasStringCtorName)),
hasArgument(1, cxxDefaultArgExpr()))));
// Match a string constructor expression with an empty string literal.
const auto EmptyStringCtorExpr = cxxConstructExpr(
StringConstructorExpr,
hasArgument(0, ignoringParenImpCasts(stringLiteral(hasSize(0)))));
const auto EmptyStringCtorExprWithTemporaries =
cxxConstructExpr(StringConstructorExpr,
hasArgument(0, ignoringImplicit(EmptyStringCtorExpr)));
const auto StringType = hasType(hasUnqualifiedDesugaredType(
recordType(hasDeclaration(cxxRecordDecl(HasStringTypeName)))));
const auto EmptyStringInit = traverse(
TK_AsIs, expr(ignoringImplicit(anyOf(
EmptyStringCtorExpr, EmptyStringCtorExprWithTemporaries))));
// Match a variable declaration with an empty string literal as initializer.
// Examples:
// string foo = "";
// string bar("");
Finder->addMatcher(
traverse(TK_AsIs,
namedDecl(varDecl(StringType, hasInitializer(EmptyStringInit))
.bind("vardecl"),
unless(parmVarDecl()))),
this);
// Match a field declaration with an empty string literal as initializer.
Finder->addMatcher(
namedDecl(fieldDecl(StringType, hasInClassInitializer(EmptyStringInit))
.bind("fieldDecl")),
this);
// Matches Constructor Initializers with an empty string literal as
// initializer.
// Examples:
// Foo() : SomeString("") {}
Finder->addMatcher(
cxxCtorInitializer(
isWritten(),
forField(allOf(StringType, optionally(hasInClassInitializer(
EmptyStringInit.bind("empty_init"))))),
withInitializer(EmptyStringInit))
.bind("ctorInit"),
this);
}
void RedundantStringInitCheck::check(const MatchFinder::MatchResult &Result) {
if (const auto *VDecl = Result.Nodes.getNodeAs<VarDecl>("vardecl")) {
// VarDecl's getSourceRange() spans 'string foo = ""' or 'string bar("")'.
// So start at getLocation() to span just 'foo = ""' or 'bar("")'.
SourceRange ReplaceRange(VDecl->getLocation(), VDecl->getEndLoc());
diag(VDecl->getLocation(), "redundant string initialization")
<< FixItHint::CreateReplacement(ReplaceRange, VDecl->getName());
}
if (const auto *FDecl = Result.Nodes.getNodeAs<FieldDecl>("fieldDecl")) {
// FieldDecl's getSourceRange() spans 'string foo = ""'.
// So start at getLocation() to span just 'foo = ""'.
SourceRange ReplaceRange(FDecl->getLocation(), FDecl->getEndLoc());
diag(FDecl->getLocation(), "redundant string initialization")
<< FixItHint::CreateReplacement(ReplaceRange, FDecl->getName());
}
if (const auto *CtorInit =
Result.Nodes.getNodeAs<CXXCtorInitializer>("ctorInit")) {
if (const FieldDecl *Member = CtorInit->getMember()) {
if (!Member->hasInClassInitializer() ||
Result.Nodes.getNodeAs<Expr>("empty_init")) {
// The String isn't declared in the class with an initializer or its
// declared with a redundant initializer, which will be removed. Either
// way the string will be default initialized, therefore we can remove
// the constructor initializer entirely.
diag(CtorInit->getMemberLocation(), "redundant string initialization")
<< FixItHint::CreateRemoval(CtorInit->getSourceRange());
return;
}
}
const CXXConstructExpr *Construct = getConstructExpr(*CtorInit);
if (!Construct)
return;
if (llvm::Optional<SourceRange> RemovalRange =
getConstructExprArgRange(*Construct))
diag(CtorInit->getMemberLocation(), "redundant string initialization")
<< FixItHint::CreateRemoval(*RemovalRange);
}
}
} // namespace readability
} // namespace tidy
} // namespace clang
|
