A method and a device for detecting memory leakage of an object

Abstract

The invention relates to a method and device for detecting memory leakage of an object, and belongs to the technical field of computers. The method comprises the following steps that A, testing according to a preset testing rule, monitoring and recording reference counting operation and a current reference counting value of a to-be-monitored object, and the reference counting operation comprises reference counting plus 1 operation and reference counting minus 1 operation; B, after the test is finished, reading the reference count value of each object to be monitored, and screening a memory leakage object which is an object with a non-zero reference count value in the objects to be monitored; C, repeating the test in the step A again, and monitoring and recording corresponding call stack information when a memory leakage object has a reference counting operation; and D, analyzing the information of the call stack, searching the call stack which is not matched with the operation of adding 1 to the reference count and subtracting 1 from the reference count, and positioning the code block corresponding to the call stack. According to the method and the device, the reason of memory leakage can be quickly analyzed, so that a program developer can repair bugs more easily.

Description

technical field [0001] The invention relates to a method and device for detecting memory leakage of an object, belonging to the technical field of computers. Background technique [0002] Various types of applications developed by C++ generally use the method of reference counting to maintain the life cycle of the corresponding objects. [0003] The most basic form of reference counting is to associate each managed object with a reference counter, which records the number of times the object is currently referenced, and the counter is incremented whenever a new reference is created to point to the object. 1, the counter is decremented by 1 each time the reference to the object becomes invalid. When the value of this counter drops to 0, the object is considered dead. Each counter only records the local information of its corresponding object - the number of references, without the global reference information of the object; [0004] 1) When a circular reference occurs, the...

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Problems solved by technology

[0004] 1) When a circular reference occurs, the object may not be released correctly (when object A and object B refer to each other as their own member variables, and only when they are destroyed by themselves, the reference count of the member variable can be reduced by 1, because the object The destruction of A depends on the destruction of object B, and the destruction of object B depends on the destruction of object A, which causes circular references, even if no external pointer can access them, they still cannot be released)

[0005] 2) Since the objects are referenced layer by layer, when it is very complex, the reference count mismatch may occur due to improper operation. Once it occurs, some objects will never be released and cause memory leaks

[0006] When a memory leak occurs, it is extremely difficult to find the root cause of the problem. The commonly used tool umdh can often only locate which line of code causes the memory leak, but how the leak occurs, you need to read the context of the line of code, and how to search layer by layer. The count does not match, the workload is large and cumbersome

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