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.

A system and method for pointer analysis for computer program verification includes forming a subset or cluster of pointers from pointers in a program by applying increasingly accurate alias analyses in a cascaded fashion such that each analysis works on a subset of pointers generated by a previous analysis's results. Aliases are computed for any pointer by computing aliases in the subsets in parallel instead of an entire program. For carrying out context and flow-sensitive alias analysis, function summaries are computed on small subsets in a top-down manner based on the points-to hierarchy which reduces the sizes of the summaries.

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.

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 system and method for analyzing a concurrent program employ asynchronous function calls for communication and recursion. A control flow graph is constructed based on a context-sensitive pointer analysis, whereupon encountering a function pointer, a points-to set of the function pointer is computed in a context-sensitive fashion to determine a set of potential function calls. The context-sensitive pointer analysis is terminated when no new potential function calls are encountered and where the potential function calls may contribute new data races other than those that exist in the contexts traversed thus far. To decide this, a characterization of pointer aliasing based upon complete update sequences is employed. A set of contexts that may contribute to different data races are enumerated by tracking update sequences for function and lock pointers and pointers that are shared or point to shared memory locations. Data race detection is carried out on the control flow graph.

A data-dependent analysis assistance device: for all pointers used in a program, performs context-sensitive pointer analysis and computes pointer information; for an area for analysis and for all program lines that could be called when the area for analysis is executed, performs context-sensitive data flow analysis using the context-sensitive pointer information; computes program line-to-program line data flow information; and, using the data flow information, computes area-to-area data-dependent information in two or more threaded areas contained in a source program.

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.

This invention relates to a method for plugging unload bytes of SDH / SONET and a circuit including generating high-low order channel to load the data stream, among which, the effective pointer value is plugged into H6, H2 high-order pointer positions to the high-order channel, zero bytes are plugged into other overhead bytes and net charge positions, thus, C2 bytes are zero and the lower reach device receives the channel without loading instruction information, the effective pointer value is given at V1, V2 bytes and zero is plugged into other overhead and net charge positions to realize that zero is plugged into the V5 byte unload bit so as to realize low order unload plug, which omits the pointer analysis circuit.

The present invention discloses a method for analyzing and optimizing a deep structure pointer of a source library pattern defect detector, comprising the following steps: first collecting related functions related to Source-Sink, and then analyzing the collected related functions on a function call graph to obtain the function call graph Subgraph, then analyze the adjacent two points in the subgraph to obtain the segmented source-sink reachability judgment result, and finally carry out the cross / merge operation summary to the segmented results to obtain the source-sink overall judgment condition; the present invention comprehensively utilizes multiple A static code analysis technology that uses a heuristic algorithm to automatically split the source-sink pattern problem with high complexity into several simple sub-problems, and then judges each sub-problem individually. For undecidable problems, it can narrow the scope of influence, Correlation functions with relatively close correlation levels are given to facilitate manual verification and can effectively reduce the false negative rate of code analysis results.

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.

Embodiments of the present invention provide a pointer analysis method and device. The pointer analysis method provided by the present invention includes: reading statement information in the multi-threaded program to be analyzed; performing pointer analysis on the program according to the statement information of the program to obtain shared information of the program, the shared information It includes shared amount, pointer pointing set and memory access behavior, wherein the shared amount includes global shared amount and local shared amount; compensation analysis is performed on the shared amount according to the shared information of the program. The embodiment of the present invention solves the problem in the prior art that the pointer analysis of multi-threaded programs is limited to the global share in the program, and the analysis results are not comprehensive, improves the accuracy of pointer analysis, and correspondingly improves the implementation scope of program optimization and effects.