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
|
//===--- DanglingHandleCheck.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 "DanglingHandleCheck.h"
#include "../utils/Matchers.h"
#include "../utils/OptionsUtils.h"
#include "clang/AST/ASTContext.h"
#include "clang/ASTMatchers/ASTMatchFinder.h"
using namespace clang::ast_matchers;
using namespace clang::tidy::matchers;
namespace clang::tidy::bugprone {
namespace {
ast_matchers::internal::BindableMatcher<Stmt>
handleFrom(const ast_matchers::internal::Matcher<RecordDecl> &IsAHandle,
const ast_matchers::internal::Matcher<Expr> &Arg) {
return expr(
anyOf(cxxConstructExpr(hasDeclaration(cxxMethodDecl(ofClass(IsAHandle))),
hasArgument(0, Arg)),
cxxMemberCallExpr(hasType(hasUnqualifiedDesugaredType(recordType(
hasDeclaration(cxxRecordDecl(IsAHandle))))),
callee(memberExpr(member(cxxConversionDecl()))),
on(Arg))));
}
ast_matchers::internal::Matcher<Stmt> handleFromTemporaryValue(
const ast_matchers::internal::Matcher<RecordDecl> &IsAHandle) {
// If a ternary operator returns a temporary value, then both branches hold a
// temporary value. If one of them is not a temporary then it must be copied
// into one to satisfy the type of the operator.
const auto TemporaryTernary =
conditionalOperator(hasTrueExpression(cxxBindTemporaryExpr()),
hasFalseExpression(cxxBindTemporaryExpr()));
return handleFrom(IsAHandle, anyOf(cxxBindTemporaryExpr(), TemporaryTernary));
}
ast_matchers::internal::Matcher<RecordDecl> isASequence() {
return hasAnyName("::std::deque", "::std::forward_list", "::std::list",
"::std::vector");
}
ast_matchers::internal::Matcher<RecordDecl> isASet() {
return hasAnyName("::std::set", "::std::multiset", "::std::unordered_set",
"::std::unordered_multiset");
}
ast_matchers::internal::Matcher<RecordDecl> isAMap() {
return hasAnyName("::std::map", "::std::multimap", "::std::unordered_map",
"::std::unordered_multimap");
}
ast_matchers::internal::BindableMatcher<Stmt> makeContainerMatcher(
const ast_matchers::internal::Matcher<RecordDecl> &IsAHandle) {
// This matcher could be expanded to detect:
// - Constructors: eg. vector<string_view>(3, string("A"));
// - emplace*(): This requires a different logic to determine that
// the conversion will happen inside the container.
// - map's insert: This requires detecting that the pair conversion triggers
// the bug. A little more complicated than what we have now.
return callExpr(
hasAnyArgument(
ignoringParenImpCasts(handleFromTemporaryValue(IsAHandle))),
anyOf(
// For sequences: assign, push_back, resize.
cxxMemberCallExpr(
callee(functionDecl(hasAnyName("assign", "push_back", "resize"))),
on(expr(hasType(hasUnqualifiedDesugaredType(
recordType(hasDeclaration(recordDecl(isASequence())))))))),
// For sequences and sets: insert.
cxxMemberCallExpr(callee(functionDecl(hasName("insert"))),
on(expr(hasType(hasUnqualifiedDesugaredType(
recordType(hasDeclaration(recordDecl(
anyOf(isASequence(), isASet()))))))))),
// For maps: operator[].
cxxOperatorCallExpr(callee(cxxMethodDecl(ofClass(isAMap()))),
hasOverloadedOperatorName("[]"))));
}
} // anonymous namespace
DanglingHandleCheck::DanglingHandleCheck(StringRef Name,
ClangTidyContext *Context)
: ClangTidyCheck(Name, Context),
HandleClasses(utils::options::parseStringList(Options.get(
"HandleClasses",
"std::basic_string_view;std::experimental::basic_string_view"))),
IsAHandle(cxxRecordDecl(hasAnyName(HandleClasses)).bind("handle")) {}
void DanglingHandleCheck::storeOptions(ClangTidyOptions::OptionMap &Opts) {
Options.store(Opts, "HandleClasses",
utils::options::serializeStringList(HandleClasses));
}
void DanglingHandleCheck::registerMatchersForVariables(MatchFinder *Finder) {
const auto ConvertedHandle = handleFromTemporaryValue(IsAHandle);
// Find 'Handle foo(ReturnsAValue());'
Finder->addMatcher(
varDecl(hasType(hasUnqualifiedDesugaredType(
recordType(hasDeclaration(cxxRecordDecl(IsAHandle))))),
hasInitializer(
exprWithCleanups(has(ignoringParenImpCasts(ConvertedHandle)))
.bind("bad_stmt"))),
this);
// Find 'Handle foo = ReturnsAValue();'
Finder->addMatcher(
traverse(TK_AsIs,
varDecl(hasType(hasUnqualifiedDesugaredType(recordType(
hasDeclaration(cxxRecordDecl(IsAHandle))))),
unless(parmVarDecl()),
hasInitializer(exprWithCleanups(
has(ignoringParenImpCasts(handleFrom(
IsAHandle, ConvertedHandle))))
.bind("bad_stmt")))),
this);
// Find 'foo = ReturnsAValue(); // foo is Handle'
Finder->addMatcher(
traverse(TK_AsIs,
cxxOperatorCallExpr(callee(cxxMethodDecl(ofClass(IsAHandle))),
hasOverloadedOperatorName("="),
hasArgument(1, ConvertedHandle))
.bind("bad_stmt")),
this);
// Container insertions that will dangle.
Finder->addMatcher(
traverse(TK_AsIs, makeContainerMatcher(IsAHandle).bind("bad_stmt")),
this);
}
void DanglingHandleCheck::registerMatchersForReturn(MatchFinder *Finder) {
// Return a local.
Finder->addMatcher(
traverse(
TK_AsIs,
returnStmt(
// The AST contains two constructor calls:
// 1. Value to Handle conversion.
// 2. Handle copy construction.
// We have to match both.
has(ignoringImplicit(handleFrom(
IsAHandle,
handleFrom(IsAHandle,
declRefExpr(to(varDecl(
// Is function scope ...
hasAutomaticStorageDuration(),
// ... and it is a local array or Value.
anyOf(hasType(arrayType()),
hasType(hasUnqualifiedDesugaredType(
recordType(hasDeclaration(recordDecl(
unless(IsAHandle)))))))))))))),
// Temporary fix for false positives inside lambdas.
unless(hasAncestor(lambdaExpr())))
.bind("bad_stmt")),
this);
// Return a temporary.
Finder->addMatcher(
traverse(
TK_AsIs,
returnStmt(has(exprWithCleanups(has(ignoringParenImpCasts(handleFrom(
IsAHandle, handleFromTemporaryValue(IsAHandle)))))))
.bind("bad_stmt")),
this);
}
void DanglingHandleCheck::registerMatchers(MatchFinder *Finder) {
registerMatchersForVariables(Finder);
registerMatchersForReturn(Finder);
}
void DanglingHandleCheck::check(const MatchFinder::MatchResult &Result) {
auto *Handle = Result.Nodes.getNodeAs<CXXRecordDecl>("handle");
diag(Result.Nodes.getNodeAs<Stmt>("bad_stmt")->getBeginLoc(),
"%0 outlives its value")
<< Handle->getQualifiedNameAsString();
}
} // namespace clang::tidy::bugprone
|
