KR100248435B1 - Detecting method of dangerous control flow for chill programming language - Google Patents

Abstract

The present invention relates to a method for detecting dangerous control movements in a program that dangerously branches by a GOTO statement or an EXIT statement at a static time for a CHILL programming language, and detects a control movement statement while traversing an abstract syntax tree. If the information on the label of the control door is found, the location of the label is examined to determine the label information of the detected control door. By providing a method of detecting dangerous control movements for the fill language that judges whether or not and outputs an appropriate diagnostic message, it is possible to automatically diagnose dangerous control movements in the fill program at a static time, thereby creating a reliable fill program, and controlling flow. It has the effect of improving the quality of software through analysis .

Description

How to detect dangerous control movements for seven languages

The present invention relates to a method for detecting dangerous control movements in a program at a static time for a seven programming language, and more particularly, to a method for detecting a dangerous branching by a GOTO statement or an EXIT statement.

Control movement statements are more likely to cause unexpected situations and are more likely to cause fatal errors not intended by the program developer because they are not related to grammatical errors in the program. Software errors can occur at any stage of the planning process, including inaccuracies in the definition of a problem, subjective interpretation of the requirements by the developer, difficulty in the design phase of switching to software representation, and coding. The results of research in software engineering indicate that the faster the discovery and correction of errors inherent in software, the more economically. To write a reliable exchange program, it is necessary to find and correct an error part early. Although the debugger is a powerful and essential tool for fixing errors in a program, it is burdensome to fix them while tracking the execution of the program. To overcome these shortcomings of the debugger, many static analysis methods are used to analyze the program before or when it is compiled. These tools are not burdened at run time because they run at or before compilation. It also has the advantage that it does not only consider an instance of program execution but also analyzes the program itself.

Conventionally, as a debugging tool for error correction of the program, a static analyzer such as lint and LOGISCOPE was used.

Lint is open source software that diagnoses C programs statically. Lint finds bugs, is not portable or unnecessary, and performs more powerful type checking than the C compiler. Lint also diagnoses the correct use of data and the correct flow of control.

Logiscope is a software analysis tool developed by Verilog. The results of this analysis can be useful for software development and maintenance. And, the logscope can do static analysis, and as a result it is possible to generate diagnostics, call graphs, and control flow graphs for the quality of the software. Dynamic analysis is also possible, and test results can be automatically generated using the analysis results to simulate software performance. Logiscope is designed for the analysis of general purpose procedural languages, and this design method has the advantage that there are many languages to be applied, but it has the disadvantage of inefficiency for a specific language. In addition, these systems have a problem that the functions of visibility analysis and parallel analysis of the seven languages are not considered.

In order to solve the above problem, the present invention detects a control movement statement while traversing an abstract syntax tree, grasps the label information of the detected control movement statement, and outputs an appropriate diagnostic message if there is no information on the label. When the information on the label of the moving statement is known, the location of the label is examined to determine whether it is inside the block statement and to provide a dangerous control movement detection method for the seven languages that outputs an appropriate diagnostic message. The goal is to automatically diagnose movement at static times.

1 is a hardware system configuration to which the present invention is applied,

2 is an internal configuration diagram of a chill compiler diagnostic unit according to the present invention;

3 is an overall process flow diagram for hazardous control movement detection in accordance with the present invention;

4 is a detailed processing flowchart of the control moving door detection step of FIG. 3;

5 is a detailed processing flowchart of the information collecting step for the control mobile door label of FIG. 3;

FIG. 6 is a detailed processing flowchart of the suitability determination step of the control mobile door of FIG. 3; FIG.

<Explanation of symbols for main parts of drawing>

101: main memory board 102: central processing unit

103: auxiliary memory 104: input / output device

105: Unix Operating System 106: System Bus

The present invention relates to a method for detecting dangerous control movements in a program at a static time for a CHILL programming language, and more particularly, to a method for detecting a dangerous branching by a GOTO statement or an EXIT statement.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram of a hardware system to which the present invention is applied, and includes a main memory board 101 of a system in which a program for analyzing a control flow at a static time by analyzing seven source codes created by a user, and the main memory board. Central processing board 102 for executing files mounted in 101, auxiliary storage 103 for storing files and data used in the system, and all error messages and results generated during dangerous control movement detection execution. Input / output device 104 for inputting / outputting the devices, the Unix operating system 105 for controlling the boards and devices, and the system bus 106 for transmitting messages and information exchanged between the boards and devices. It is composed.

2 is an internal configuration diagram of a chill compiler diagnostic unit according to the present invention.

The diagnosis unit of the Chill compiler for control flow analysis generates the abstract syntax tree for the symbol table and the execution statement for the data while simultaneously parsing the input program in the parser 201 and simultaneously parsing the entire program structure unit 205. In this case, the visibility control unit 202 analyzes the visibility of the symbol table and the abstract syntax tree output from the parser 201, and displays name information disconnected between modules. The symbol table is reconstructed using GRANT / SEIZE information received from the outside, and the semantic analysis unit 203 performs semantic analysis of the program using the symbol table output from the visibility control unit 202. When the control flow analyzing unit 204 outputs the output signal of the semantic analyzing unit 203 by analyzing the control flow at a static time, the dangerous control movement detection output unit 206 finally outputs a diagnosis result.

3 is an overall process flow diagram for hazardous control movement detection in accordance with the present invention.

First, it is determined whether or not the end of the unit program (300), and if it is the end, if it is not the end, it detects the control movement statement (GOTO statement, EXIT statement) while traversing the abstract syntax tree (400). If the control movement door is found in step 400, the controller determines the information on the label of the found control movement door and outputs an appropriate diagnostic message if there is no information on the label (500). When the information on the label of the control movement statement is grasped according to the result of step 500, the position of the label is examined to determine whether it is inside the block statement (IF statement, DO statement, or CASE statement), and to output an appropriate diagnostic message. (600). Each of the above steps is repeated until the end of the unit program.

4 is a detailed process flowchart of the control mobile door detection step of FIG.

First, it is determined whether the node of the abstract syntax tree is last (401). If it is the last, it is terminated. If not, it is determined whether it is a nonterminal type (402). In step 402, if the node is a non-terminal type, it is determined whether the node name is a control movement statement (403), and if it is not a non-terminal type, a pointer of the node is moved to a sibling node (406). Returning to 401, the above steps are repeated. In step 403, if the node name is the control movement statement, the label information of the control movement statement is detected (404). If the node name is not the control movement statement, the node re-calls itself with the child node of the current node as a factor (405). . Steps 404 and 405 then move the node's pointer to the sibling node 406 and then back to step 401, ending if the node of the abstract syntax tree is last and again if not last. Repeat the above steps.

FIG. 5 is a detailed processing flowchart of the information collecting step for the control mobile door label of FIG. 3.

First, information on the label of the control movement statement is obtained (501), and whether the label information is present and whether the class of the name corresponds to the execution statement of the program is judged to determine whether the label information is correct ( 502) If the label information is correct, the label position of the control moving door is checked (503). If the label information is incorrect, an appropriate warning message is output and the process ends (504). In step 503, it is checked whether the position of the label checked is in the current block (505). In step 505, it is determined whether or not the label exists in the current block (505). If it is present, it terminates. If not, an appropriate warning message is output (506) and then terminated.

6 is a detailed processing flowchart of the suitability determination step of the control mobile door of FIG.

It is determined whether the node of the abstract syntax tree is last (601). If it is the last, it is terminated. If not, it is determined whether it is a non-terminal type (602). In step 602, if the non-terminal type is a non-terminal type, check whether the node name is a block statement (603), if not in the non-terminal type, move the pointer of the node to a sibling node (606), and then return to step 601. Repeat the above steps again. In step 603, if the node name is not a block statement, the node is called again with the child node of the current node as an argument (605). If the node name is a block statement, the label is detected by detecting a label inside the block statement. If it does, it outputs a warning message (604), then calls itself again with the child node of the current node as an argument (605), moves the node's pointer to a sibling node (606), and returns to step 601 to abstract it. Terminates when the node of the syntax tree is last.

The present invention detects the control movement statement while traversing the abstract syntax tree, grasps the label information of the detected control movement statement, outputs an appropriate diagnostic message if there is no information on the label, and provides information on the label of the control movement statement. Once identified, it provides a method of detecting dangerous control movements in a chilled language that automatically detects dangerous control movements within a chilling program at static times by examining the location of the label to determine whether it is inside a block statement and output an appropriate diagnostic message. By diagnosing, it is possible to create a reliable fill program and to improve the quality of software through control flow analysis.

Claims (4)

In the CHILL programming language, a method of detecting dangerous control movement in a program that is dangerously branched by a GOTO statement or an EXIT statement at a static time, Determining whether or not the end of the unit program is completed; A second step of detecting a control movement statement (GOTO statement, EXIT statement) while traversing the abstract syntax tree when the first step is not the end; A third step of identifying information on a label of the found control door and outputting an appropriate diagnostic message when the control door is found in the second step; When the information on the label of the control movement statement is grasped according to the result of the third process, the position of the label is examined to determine whether it is inside the block statement (IF statement, DO statement, CASE statement), and to output an appropriate diagnostic message. And a fourth process of repeating each process until the end of a unit program is returned to the first process again. The method of claim 1, The second process includes: a first step of determining whether a node of the abstract syntax tree is an end and ending if it is an end; A second step of determining whether the terminal is non-terminal if not in the first step; A third step of determining whether the node name is a control mobile statement when the terminal is non-terminal in the second step; A fourth step of detecting label information of the control mobile statement when the node name is the control mobile statement in the third step; A fifth step of calling itself again with a child node of the current node when the node name is not a control movement statement in the third step; If the terminal is not non-terminal in the second step or after performing the fourth or fifth step, the pointer of the node is moved to the sibling node, and the node of the abstract syntax tree ends again by returning to the first step. And a sixth step of repeating the above steps until the dangerous control movement detection method for the seven languages. The method of claim 1, The third process includes: a first step of obtaining information on a label of a control moving door; A second step of determining whether the label information is correct by checking whether the label information obtained in the first step and the class of the name correspond to an execution statement of the program; A third step of outputting and terminating an appropriate warning message if the label information is incorrect in the second step; A fourth step of checking the label position of the control door when the label information is correct in the second step; A fifth step of determining whether the position of the label checked in the fourth step exists in the current block; A sixth step of outputting a warning message and terminating if it is not present in the fifth step; And a seventh step of terminating if present in the fifth step. The method of claim 1, The fourth process includes: a first step of determining whether a node of the abstract syntax tree is an end, and ending if it is an end; A second step of determining whether the terminal is non-terminal if not in the first step; A third step of determining whether or not the node name is a block statement when the non-terminal type is used in the second step; A fourth step of detecting whether a label exists inside the block statement when the node name is a block statement and outputting a warning message if the node name is a block statement; A fifth step of calling the node again with the child node of the current node when the node name is not a block statement in the third step or after performing the fourth step; If the second step is not a non-terminal type or after performing the fifth step, move the pointer of the node to the sibling node, and return to the first step until the node of the abstract syntax tree ends. And a repeating sixth step.

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