40 results about "Pointer analysis" patented technology

This invention describes a compilation method of extracting and implementing an accelerator control program from an application source code in a processor based system. The application source code comprises arrays and loops. The input application source code is sequential, with loop, branch and call control structures, while the generated output of this invention has parallel execution semantics. The compilation method comprises the step of performing loop nest analysis, transformations and backend processes. The step of loop nest analysis consists of dependence analysis and pointer analysis. Dependence analysis determines the conflicts between the various references to arrays in the loop, and pointer analysis determines if two pointer references in a loop are in conflict. Transformations convert the loops from their original sequential execution semantics to parallel execution semantics. The back-end process determines the parameters and memory map of the accelerator and the hardware dependent software.

The invention discloses a method of fully detecting null pointer reference defects. The method comprises recognizing all addressable expressions of an application to be detected based on an abstract syntax tree; carrying out conservative interval arithmetic and pointer analysis on the application to be detected according to a control flow diagram, and generating a procedural summary according to results of the interval arithmetic and the pointer analysis; recognizing all pointer reference and referred pointers according to the procedural summary and the abstract syntax tree, and creating a null pointer reference defect state machine example on each referred pointer; and running the null pointer reference defect state machine examples based on the control flow diagram, carrying out state transition on each defect state machine example on each node of the control flow diagram according to the results of the interval arithmetic and the pointer analysis, and carrying out null pointer reference detection. By adopting the method of fully detecting the null pointer reference defects, the problem of failing to report the null pointer reference defects can be effectively solved, and zero omission and low misinformation of the null pointer reference defect detection are achieved.

The invention relates to a software security hole dynamic detection method, in particular to a pointer analysis-combined software security hole dynamic detection method, and belongs to the technical field of information security. The software security hole dynamic detection method comprises the following steps of: identifying insecure pointers in a program to be detected; expressing the insecure pointers as fat pointers; and continuously checking the pointer state information contained in the fat pointers and finding the hole existing in the program to be detected by operating the program to be detected. The software security hole dynamic detection method can detect various holes simultaneously, such as a buffer area overflow hole, a suspended pointer hole, and the like, and can reduce the consumption of the system resources simultaneously.

A data dependence analysis support device calculates pointer information by performing a context-sensitive pointer analysis on every pointer used in a program; calculates dataflow information between statements by performing a context-sensitive dataflow analysis, using the context-sensitive pointer information, on all statements in an analysis target region and all statements that might be called upon execution of the analysis target region; and calculates inter-region data dependence information, using the dataflow information, for two or more threaded regions included in the source program.

The invention relates to a wave beam residence scheduling method of a cooperative distributed system, and belongs to the field of radar system resource management. The priority of a task work manner and influence of deadline on the task priority are both taken into consideration, an HPEDF method is used to calculate the integrated priority, a wave beam residence scheduling model is established according to characteristics of radar task scheduling enforced by multiple stations cooperatively in the cooperative distributed system, a time pointer analysis based heuristic method is used for solution, and the method is formed. The problem that a sub-radar needs to work independently but also needs wave beam residence scheduling during cooperative work is solved.

A “Demand-Driven Pointer Analyzer” (DDPA) provides a “demand-driven” field-sensitive pointer analysis process. This process rapidly and accurately identifies alias sets for selected pointers in software modules or programs of any size, including large-scale C/C++ programs such as a complete operating system (OS). The DDPA formulates the pointer analysis task as a Context-Free Language (CFL) reachability problem that operates using a Program Expression Graph (PEG) automatically constructed from the program code. The PEG provides a node and edge-based graph representation of all expressions and assignments in the program and allows the DDPA to rapidly identify aliases for pointers in the program by traversing the graph as a CFL reachability problem to determine pointer alias sets. In various embodiments, the DDPA is also context-sensitive.

A software vulnerability detection method based on pointer analysis includes the following steps that with the help of instrumentation software, three main instrumentation operations of basic data type recovery, complex data type recovery and vulnerability detection are respectively finished, wherein the instrumentation operation of basic data type recovery includes the processes that type collection codes are inserted behind instructions belonging to a type sensitive instruction set, and then propagation codes of different types are inserted according to different assembly instructions; the instrumentation operation of complex data type recovery includes the processes that pointer collection codes are inserted behind a memory application instruction set, pointer analysis codes are inserted according to different assembly instructions, and then complex data types are recovered in the pointer analysis process; the instrumentation operation of vulnerability detection includes the processes that pollution marking codes are inserted to external input positions of programs, stain spreading codes are inserted according to assembly instructions, and security detection codes are inserted to security sensitive points.

The embodiment of the invention discloses a C language defect detection method and device based on multi-level analysis. The method comprises the following steps: calculating pointer pointing information of each function in the function call relation graph based on a path-sensitive pointer analysis method; performing inter-process analysis on a calling function corresponding to a function callingstatement in the function calling relational graph to obtain abstract information of the calling function; aiming at each node in the control flow graph, determining a control dependence correspondingrelation and a data dependence corresponding relation corresponding to the node; and generating a value flow graph according to the pointer pointing information of each function, the abstract information of the calling function, the control dependence corresponding relation corresponding to each node and the data dependence corresponding relation, and performing defect detection on the to-be-detected C language program according to the value flow graph to obtain a detection result. By applying the scheme provided by the embodiment of the invention, the accuracy and efficiency of defect detection can be considered.

The invention discloses an assembly level interprocedual pointer analysis method based on speculative multithreading. Through assembly level interprocedual points-to analysis, a procedure call graph of all processes is established in a source program before the interprocedual points-to analysis is carried out, and after establishment, points-to analysis is carried out in two stages. The method comprises: in the first stage, firstly, establishing a path profiling cost model based on probability, extracting speculative paths selected by all process nodes in the procedure call graph, and then performing points-to analysis in a process; in the second stage, performing interprocedual points-to analysis and interprocedual side-effect calculation, on each process calling point, performing mappingand inverse mapping on points-to relations using a points-to analysis result in a process, to obtain an interprocedual side-effect calculation result, and realize context points-to relation update ofa calling procedure. On this basis, the method guides a whole procedure to perform interprocedual data flow analysis, evaluates data dependence degree among pointer variable memory points-to relations, and obtains a more accurate thread partitioning result.

The invention discloses a method for intelligently detecting C program memory leakage based on machine learning. The method has three stages; in a model construction stage, two data sets are constructed according to original memory leakage; memory leakage characteristics are extracted respectively from the two data sets; the memory leakage characteristics are input into a machine learning classifier, so that training and cross validation are carried out; the type and the parameter of the classifier are modified; the memory leakage is detected by taking the classifier having highest classification accuracy rate as the classifier model; in a program analysis and characteristic obtaining stage, a source program is pre-analyzed; all memory allocation points o are obtained; then, pointer analysis is carried out; a VFG (Value Flow Graph) at the beginning of o is constructed; the memory leakage characteristics corresponding to each path in the VFG are extracted; in a defect detection and report stage, the memory leakage characteristics in the program analysis and characteristic obtaining stage are input into the classifier model in the model construction stage and detected; whether memoryleakage exists in a path at the beginning of o or not is judged; and thus, a memory leakage report is obtained.

Pointer analysis is used for different applications, e.g., compilers, debugging tools and programs understanding tools, each having different requirements. A framework for pointer analysis is provided that defines a multidimensional space, for example a three-dimensional space, containing an order sensitivity dimension, a predicate sensitivity dimension and a value persistence dimension. A point in the three-dimensional space is identified. This point yields values for order sensitivity, predicate sensitivity and value persistence. Pointer analysis is then conducted on a computer program in accordance with the identified values for order sensitivity, predicate sensitivity and value persistence.

The invention discloses a GPU-based large-scale software high-precision static analysis method. The method comprises the following steps of: firstly, converting a series of specific program analysis,such as pointer analysis, data flow analysis, program slicing and the like, into a special graph accessibility problem, namely a context independent language (CFL) accessibility problem; Transmittingthe converted program chart and the corresponding grammar rule to a graphics processing unit (GPU) to carry out parallel CFL reachability calculation, namely dynamically adding edges according to thegrammar rule until a fixed point is reached; And if the size of the graph exceeds the limited value of the video memory, only part of data can be called to participate in calculation each time, and the rest is stored in a hard disk. By utilizing the GPU and the external memory, the method disclosed by the invention has relatively high efficiency and expandability, and can be used for carrying outcomplex code analysis on a large-scale software system.

The invention discloses a system suitable for the analysis control of an AU/TU pointer, which comprises the sub-block of a pointer analysis state machine, a pointer type state machine and an I/D bit inversion detection module, wherein the pointer type state machine is used for judging and outputting the type of state indication according to the current pointer value; the I/D bit inversion detection module is used for indicating the adjustment indication type of the pointer; the pointer analysis LOP/AIS/NORMAL state machine sub-block uses the pointer type which is generated by the pointer analysis state machine as the basis to carry out the state skip and output pointer loss state indication and alarm state indication; the initial state in the resetting course is used as the loss state of the pointer; and the pointer value updating sub-block updates the value of the pointer and outputs positive adjustment indication signals, negative adjustment indication signals and new pointer adjustment indication signals according to the positive and negative adjustment indication and new data pointer adjustment indication which are generated by the pointer analysis state machine. The system disclosed by the invention solves the dispersity of the existing pointer analysis treatment of an SDH (synchronous digital hierarchy).

The invention discloses a source code scanning tool, method and device and a medium, and the tool comprises an analysis module which is used for analyzing a program source code, so as to generate a question dictionary corresponding to a third-party assembly; wherein a problem in the problem dictionary is a grammar corresponding to the third-party part which cannot be identified by the analysis module; third-party part parsing engine, the searching module is used for searching a function fragment of the third-party part referenced by the program source code corresponding to the question in thequestion dictionary; and storing the function segment and a context in the program source code corresponding to the problem as a target program segment in a target file, and calling back a pointer ofthe target file to the analysis module, so that the analysis module analyzes the target program segment through the pointer to obtain a corresponding analysis result. Therefore, the missing report rate of the source code problem can be reduced, and the accuracy of reporting the source code problem is improved.