1 // Copyright 2018 The Abseil Authors.
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License");
4 // you may not use this file except in compliance with the License.
5 // You may obtain a copy of the License at
6 //
7 // https://www.apache.org/licenses/LICENSE-2.0
8 //
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS,
11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 // See the License for the specific language governing permissions and
13 // limitations under the License.
14 //
15 // -----------------------------------------------------------------------------
16 // File: leak_check.h
17 // -----------------------------------------------------------------------------
18 //
19 // This file contains functions that affect leak checking behavior within
20 // targets built with the LeakSanitizer (LSan), a memory leak detector that is
21 // integrated within the AddressSanitizer (ASan) as an additional component, or
22 // which can be used standalone. LSan and ASan are included (or can be provided)
23 // as additional components for most compilers such as Clang, gcc and MSVC.
24 // Note: this leak checking API is not yet supported in MSVC.
25 // Leak checking is enabled by default in all ASan builds.
26 //
27 // See https://github.com/google/sanitizers/wiki/AddressSanitizerLeakSanitizer
28 //
29 // -----------------------------------------------------------------------------
30 #ifndef ABSL_DEBUGGING_LEAK_CHECK_H_
31 #define ABSL_DEBUGGING_LEAK_CHECK_H_
32
33 #include <cstddef>
34
35 #include "absl/base/config.h"
36
37 namespace absl {
38 ABSL_NAMESPACE_BEGIN
39
40 // HaveLeakSanitizer()
41 //
42 // Returns true if a leak-checking sanitizer (either ASan or standalone LSan) is
43 // currently built into this target.
44 bool HaveLeakSanitizer();
45
46 // LeakCheckerIsActive()
47 //
48 // Returns true if a leak-checking sanitizer (either ASan or standalone LSan) is
49 // currently built into this target and is turned on.
50 bool LeakCheckerIsActive();
51
52 // DoIgnoreLeak()
53 //
54 // Implements `IgnoreLeak()` below. This function should usually
55 // not be called directly; calling `IgnoreLeak()` is preferred.
56 void DoIgnoreLeak(const void* ptr);
57
58 // IgnoreLeak()
59 //
60 // Instruct the leak sanitizer to ignore leak warnings on the object referenced
61 // by the passed pointer, as well as all heap objects transitively referenced
62 // by it. The passed object pointer can point to either the beginning of the
63 // object or anywhere within it.
64 //
65 // Example:
66 //
67 // static T* obj = IgnoreLeak(new T(...));
68 //
69 // If the passed `ptr` does not point to an actively allocated object at the
70 // time `IgnoreLeak()` is called, the call is a no-op; if it is actively
71 // allocated, leak sanitizer will assume this object is referenced even if
72 // there is no actual reference in user memory.
73 //
74 template <typename T>
IgnoreLeak(T * ptr)75 T* IgnoreLeak(T* ptr) {
76 DoIgnoreLeak(ptr);
77 return ptr;
78 }
79
80 // FindAndReportLeaks()
81 //
82 // If any leaks are detected, prints a leak report and returns true. This
83 // function may be called repeatedly, and does not affect end-of-process leak
84 // checking.
85 //
86 // Example:
87 // if (FindAndReportLeaks()) {
88 // ... diagnostic already printed. Exit with failure code.
89 // exit(1)
90 // }
91 bool FindAndReportLeaks();
92
93 // LeakCheckDisabler
94 //
95 // This helper class indicates that any heap allocations done in the code block
96 // covered by the scoped object, which should be allocated on the stack, will
97 // not be reported as leaks. Leak check disabling will occur within the code
98 // block and any nested function calls within the code block.
99 //
100 // Example:
101 //
102 // void Foo() {
103 // LeakCheckDisabler disabler;
104 // ... code that allocates objects whose leaks should be ignored ...
105 // }
106 //
107 // REQUIRES: Destructor runs in same thread as constructor
108 class LeakCheckDisabler {
109 public:
110 LeakCheckDisabler();
111 LeakCheckDisabler(const LeakCheckDisabler&) = delete;
112 LeakCheckDisabler& operator=(const LeakCheckDisabler&) = delete;
113 ~LeakCheckDisabler();
114 };
115
116 // RegisterLivePointers()
117 //
118 // Registers `ptr[0,size-1]` as pointers to memory that is still actively being
119 // referenced and for which leak checking should be ignored. This function is
120 // useful if you store pointers in mapped memory, for memory ranges that we know
121 // are correct but for which normal analysis would flag as leaked code.
122 void RegisterLivePointers(const void* ptr, size_t size);
123
124 // UnRegisterLivePointers()
125 //
126 // Deregisters the pointers previously marked as active in
127 // `RegisterLivePointers()`, enabling leak checking of those pointers.
128 void UnRegisterLivePointers(const void* ptr, size_t size);
129
130 ABSL_NAMESPACE_END
131 } // namespace absl
132
133 #endif // ABSL_DEBUGGING_LEAK_CHECK_H_
134