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
|
//===--- NSInvocationArgumentLifetimeCheck.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
//
//===----------------------------------------------------------------------===//
#include "NSInvocationArgumentLifetimeCheck.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/ComputeDependence.h"
#include "clang/AST/Decl.h"
#include "clang/AST/Expr.h"
#include "clang/AST/ExprObjC.h"
#include "clang/AST/Type.h"
#include "clang/AST/TypeLoc.h"
#include "clang/ASTMatchers/ASTMatchFinder.h"
#include "clang/ASTMatchers/ASTMatchers.h"
#include "clang/ASTMatchers/ASTMatchersMacros.h"
#include "clang/Basic/Diagnostic.h"
#include "clang/Basic/LLVM.h"
#include "clang/Basic/LangOptions.h"
#include "clang/Basic/SourceLocation.h"
#include "clang/Basic/SourceManager.h"
#include "clang/Lex/Lexer.h"
#include "llvm/ADT/StringRef.h"
#include <optional>
using namespace clang::ast_matchers;
namespace clang::tidy::objc {
namespace {
static constexpr StringRef WeakText = "__weak";
static constexpr StringRef StrongText = "__strong";
static constexpr StringRef UnsafeUnretainedText = "__unsafe_unretained";
/// Matches ObjCIvarRefExpr, DeclRefExpr, or MemberExpr that reference
/// Objective-C object (or block) variables or fields whose object lifetimes
/// are not __unsafe_unretained.
AST_POLYMORPHIC_MATCHER(isObjCManagedLifetime,
AST_POLYMORPHIC_SUPPORTED_TYPES(ObjCIvarRefExpr,
DeclRefExpr,
MemberExpr)) {
QualType QT = Node.getType();
return QT->isScalarType() &&
(QT->getScalarTypeKind() == Type::STK_ObjCObjectPointer ||
QT->getScalarTypeKind() == Type::STK_BlockPointer) &&
QT.getQualifiers().getObjCLifetime() > Qualifiers::OCL_ExplicitNone;
}
static std::optional<FixItHint>
fixItHintReplacementForOwnershipString(StringRef Text, CharSourceRange Range,
StringRef Ownership) {
size_t Index = Text.find(Ownership);
if (Index == StringRef::npos)
return std::nullopt;
SourceLocation Begin = Range.getBegin().getLocWithOffset(Index);
SourceLocation End = Begin.getLocWithOffset(Ownership.size());
return FixItHint::CreateReplacement(SourceRange(Begin, End),
UnsafeUnretainedText);
}
static std::optional<FixItHint>
fixItHintForVarDecl(const VarDecl *VD, const SourceManager &SM,
const LangOptions &LangOpts) {
assert(VD && "VarDecl parameter must not be null");
// Don't provide fix-its for any parameter variables at this time.
if (isa<ParmVarDecl>(VD))
return std::nullopt;
// Currently there is no way to directly get the source range for the
// __weak/__strong ObjC lifetime qualifiers, so it's necessary to string
// search in the source code.
CharSourceRange Range = Lexer::makeFileCharRange(
CharSourceRange::getTokenRange(VD->getSourceRange()), SM, LangOpts);
if (Range.isInvalid()) {
// An invalid range likely means inside a macro, in which case don't supply
// a fix-it.
return std::nullopt;
}
StringRef VarDeclText = Lexer::getSourceText(Range, SM, LangOpts);
if (std::optional<FixItHint> Hint =
fixItHintReplacementForOwnershipString(VarDeclText, Range, WeakText))
return Hint;
if (std::optional<FixItHint> Hint = fixItHintReplacementForOwnershipString(
VarDeclText, Range, StrongText))
return Hint;
return FixItHint::CreateInsertion(Range.getBegin(), "__unsafe_unretained ");
}
} // namespace
void NSInvocationArgumentLifetimeCheck::registerMatchers(MatchFinder *Finder) {
Finder->addMatcher(
traverse(
TK_AsIs,
objcMessageExpr(
hasReceiverType(asString("NSInvocation *")),
anyOf(hasSelector("getArgument:atIndex:"),
hasSelector("getReturnValue:")),
hasArgument(
0,
anyOf(hasDescendant(memberExpr(isObjCManagedLifetime())),
hasDescendant(objcIvarRefExpr(isObjCManagedLifetime())),
hasDescendant(
// Reference to variables, but when dereferencing
// to ivars/fields a more-descendent variable
// reference (e.g. self) may match with strong
// object lifetime, leading to an incorrect match.
// Exclude these conditions.
declRefExpr(to(varDecl().bind("var")),
unless(hasParent(implicitCastExpr())),
isObjCManagedLifetime())))))
.bind("call")),
this);
}
void NSInvocationArgumentLifetimeCheck::check(
const MatchFinder::MatchResult &Result) {
const auto *MatchedExpr = Result.Nodes.getNodeAs<ObjCMessageExpr>("call");
auto Diag = diag(MatchedExpr->getArg(0)->getBeginLoc(),
"NSInvocation %objcinstance0 should only pass pointers to "
"objects with ownership __unsafe_unretained")
<< MatchedExpr->getSelector();
// Only provide fix-it hints for references to local variables; fixes for
// instance variable references don't have as clear an automated fix.
const auto *VD = Result.Nodes.getNodeAs<VarDecl>("var");
if (!VD)
return;
if (auto Hint = fixItHintForVarDecl(VD, *Result.SourceManager,
Result.Context->getLangOpts()))
Diag << *Hint;
}
} // namespace clang::tidy::objc
|
