live-bindings-test.cpp source code [clang_source_code/test/Analysis/live-bindings-test.cpp]

1	// RUN: %clang_analyze_cc1 -std=c++17 -analyzer-checker=core,deadcode -verify %s
2
3	typedef unsigned long size_t;
4
5	// Machinery required for custom structured bindings decomposition.
6	namespace std {
7	template <class T> class tuple_size;
8	template <class T>
9	constexpr size_t tuple_size_v = tuple_size<T>::value;
10	template <size_t I, class T> class tuple_element;
11
12	template<class T, T v>
13	struct integral_constant {
14	static constexpr T value = v;
15	typedef T value_type;
16	typedef integral_constant type;
17	constexpr operator value_type() const noexcept { return value; }
18	};
19	}
20
21	struct S {
22	int a;
23	double b;
24	S(int a, double b) : a(a), b(b) {};
25	};
26
27	S GetNumbers();
28
29	int used_binding() {
30	const auto [a, b] = GetNumbers(); // no-warning
31	return a + b;
32	}
33
34	void no_warning_on_copy(S s) {
35	// Copy constructor might have side effects.
36	const auto [a, b] = s; // no-warning
37	}
38
39
40	int unused_binding_ignored() {
41	const auto [a, b] = GetNumbers(); // expected-warning{{Value stored to '[a, b]' during its initialization is never read}}
42	return 0;
43	}
44
45	int unused_binding_liveness_required() {
46	auto [a2, b2] = GetNumbers(); // expected-warning{{Value stored to '[a2, b2]' during its initialization is never read}}
47	a2 = 10;
48	b2 = 20;
49	return a2 + b2;
50	}
51
52	int kill_one_binding() {
53	auto [a, b] = GetNumbers(); // no-warning
54	a = 100;
55	return a + b;
56
57	}
58
59	int kill_one_binding2() {
60	auto [a, b] = GetNumbers(); // expected-warning{{Value stored to '[a, b]' during its initialization is never read}}
61	a = 100;
62	return a;
63	}
64
65	void use_const_reference_bindings() {
66	const auto &[a, b] = GetNumbers(); // no-warning
67	}
68
69	void use_reference_bindings() {
70	S s(0, 0);
71	auto &[a, b] = s; // no-warning
72	a = 200;
73	}
74
75	int read_through_pointer() {
76	auto [a, b] = GetNumbers(); // no-warning
77	int *z = &a;
78	return *z;
79	}
80
81	auto [globalA, globalB] = GetNumbers(); // no-warning, globals
82	auto [globalC, globalD] = GetNumbers(); // no-warning, globals
83
84	void use_globals() {
85	globalA = 300; // no-warning
86	globalB = 200;
87	}
88
89	struct Mytuple {
90	int a;
91	int b;
92
93	template <size_t N>
94	int get() const {
95	if constexpr (N == 0) return a;
96	else if constexpr (N == 1) return b;
97	}
98	};
99
100	namespace std {
101	template<>
102	struct tuple_size<Mytuple>
103	: std::integral_constant<size_t, 2> {};
104
105	template<size_t N>
106	struct tuple_element<N, Mytuple> {
107	using type = int;
108	};
109	}
110
111	void no_warning_on_tuple_types_copy(Mytuple t) {
112	auto [a, b] = t; // no-warning
113	}
114
115	Mytuple getMytuple();
116
117	void deconstruct_tuple_types_warning() {
118	auto [a, b] = getMytuple(); // expected-warning{{Value stored to '[a, b]' during its initialization is never read}}
119	}
120
121	int deconstruct_tuple_types_no_warning() {
122	auto [a, b] = getMytuple(); // no-warning
123	return a + b;
124	}
125

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