KR100279731B1 - How to Display Control Flow for Fill Languages - Google Patents

Abstract

The present invention relates to a control flow display method for a fill language for displaying a control flow for analyzing an execution order of a program in an exchange software programmed in a fill language. By providing a control flow display method for the seven languages that perform the processing, the module and the execution statement in the block, indentation for each node, and output to each node of the linked list, Visually indent the control structure according to the visibility structure and concurrency of the input chill source program, and the nesting relationships between the execution statements, so that the developer can clearly understand the overall flow of the program and the relationship between the execution statements, thereby making it more reliable. High fill program and control flow analysis This has the effect of improving quality.

Description

How to Display Control Flow for Fill Languages

The present invention relates to a method for displaying a control flow of an exchange software programmed in a CHILL language. In particular, the present invention relates to a control flow display method for a fill language for displaying a control flow capable of analyzing a program execution order. It is about.

Chil, a high-level programming language for making switch software, is a large and complex language that includes most of the features of existing programming languages. It is designed with reliability, efficiency, and ease of generation and modification of object code. Much of the software currently used in exchanges is written in seven languages. The exchanger must be highly reliable, so the chilling program must not contain any errors. In order to write a highly reliable program, it is necessary to find and correct the parts that may be in error.

In the past, a debugger was used as a method of detecting an error of a program that is operating incorrectly in order to prevent and correct an error. The debugger is a powerful and essential tool for error correction, but it also puts the burden of error correction as you track program execution. Therefore, as another method of improving the reliability of the program by improving the shortcomings of the debugger, the program is structured using programs that analyze and output a call relationship or a control structure in the program. Structured programs are easy to understand and reduce the likelihood of errors.

However, such a conventional debugger or a program structuring a program does not consider the visibility structure or the parallel structure of the seven languages, so that it is difficult for a software developer to understand the relationship between the entire flow and execution statements of the program.

In order to solve the above problems, the present invention, after processing the module and the block in the unit program, the processing of the execution statement in the module and the block, indentation processing for each node, By providing a control flow display method for the fill language that outputs to each node, the developer visually indents the visibility structure of the input fill source program, the control flow according to the concurrency, and the nesting relationship between execution statements. Its purpose is to provide a clear understanding of the overall flow and relationships between Sal statements.

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

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

3 is an overall flowchart of a control flow indicator in the control flow analyzer of FIG. 2;

4 is a detailed process flowchart of the modular and block information search step of FIG. 3;

FIG. 5 is a detailed processing flowchart of the information search step of the modular and intra-block execution statements of FIG. 3; FIG.

FIG. 6 is a detailed process flowchart of an indent value setting step for each node of FIG. 3;

7 is a detailed processing flowchart of a diagnostic result output step for the control flow structure of FIG.

<Explanation of symbols for main parts of drawing>

101: main memory 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 displaying a control flow of an exchange software programmed in a CHILL language. In particular, the present invention relates to a control flow display method for a fill language for displaying a control flow capable of analyzing a program execution order. It is about.

Hereinafter, with reference to the accompanying drawings will be described an embodiment of the present invention;

1 is a schematic diagram of a hardware system to which the present invention is applied and includes a main memory board 101 equipped with a chill compiler for developing a control flow indicator, and a central processing unit for executing a file mounted on the main memory board 101. Board 102, auxiliary storage 103 for storing files and data used in each board and device of the hardware system, input / output device 104 for inputting / outputting all error messages and diagnostic results, and And a Unix operating system 105 for controlling the boards and devices, and a system bus 106 for transmitting messages and information exchanged between the boards and devices.

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

First, the parser 201 lexically analyzes an input program and parses it using a LALR (1) parsing method to generate a symbol table and an abstract syntax tree (AST) to the entire program structure 205. After storing and outputting to the visibility control unit 202, the visibility control unit 202 analyzes the visibility of the symbol table and the abstract syntax tree output from the parser 201, and generates the symbol table using GRANT / SEIZE information. The semantic analysis unit 203 reconstructs the semantic analysis of the program using the symbol table output from the visibility control unit 202. In addition, the control flow analyzer 204 is added to the front end of the compiler in relation to the control structure of the program, the call relationship to the input source program, the skeleton of the control flow, the infinite loop or the unreachable code, the constant part, The contents of the dangerous control movement and the like are analyzed at a static time, and finally, the diagnosis result output unit 206 outputs the diagnosis result of the control flow analyzer 204 to a screen or a file.

3 is an overall flowchart of a control flow indicator in the control flow analyzer of FIG. 2.

The input source program is composed of symbol table and abstract syntax tree structure by the compiler front end. The abstract syntax tree is composed of 20 unit program structures. The control flow indicator first determines whether or not the 20 unit program search is completed (300). If the unit program search is not completed, the control flow indicator reads each unit program structure and reads one unit program information (400). . Next, the module searches for the information of the module and block in the unit program constituting the abstract syntax tree while traversing the abstract syntax tree associated with the unit program read in step 400 and stores the information in the linked list (500). In the same manner as in 500), the first position of each execution statement in each module and block is searched, and only the elements affecting the control of the execution statement are stored, and the information is stored in the linked list (600), and then returned to the step (300). Repeat the above steps. When the search of the unit program is completed in step 300, an indentation value is set in consideration of the connection characteristics of the nodes stored in the next connection list (700), and each node of the next connection list is sequentially read to read the entire source. The control flow of the program is visually indented and output in a list format (800).

4 is a detailed process flowchart of the modular and block information search step of FIG. 3.

First, an abstract syntax tree is searched from the beginning to check whether the node type of each node is a module and a block, thereby defining a group name for the current node (501). Here, the module and the block have a nesting structure, so they have a starting point and an ending point. Next, create and store a node to configure information about the start point of the current node into a connection list, insert the point into the connection list (502), and the information about the last point in the same manner as in step 502. Generates a node to be configured as a linked list and inserts it into the linked list (503).

FIG. 5 is a detailed process flowchart of the information search step of the modularity and intra-block execution statement of FIG. 3.

First, it is determined whether or not the node entry is null. If it is null, it is terminated (601). If not, it is determined whether or not the node entry is nonterminal (602). Here, determining whether the node entry is null in step 601 is to search all nodes on the abstract syntax tree to find the starting point of the execution statement for each of the modalities and blocks constituting the abstract syntax tree. It is for. Therefore, in step 602, only the non-terminal node of each node is found using the starting point found in step 601 as a starting point. Next, in step 602, if it is a non-terminal, only the elements that affect the control are searched, a node for the entry is created, inserted into the linked list (603), and the points are reset to sibling entries to abstract. Searching for sibling nodes in the syntax tree in turn, searching for nodes that affect the rest of the execution, and returning to step 601 again, repeating these steps until the node entry is null (604). In step 602, step 604 is performed even if the node entry is not a non-terminal.

FIG. 6 is a detailed process flowchart of an indent value setting step for each node of FIG. 3.

First, since the indentation value of the current node varies according to the indentation value of the previous node and the type of the node, the depth information about the current node and the current node is searched for in the connection list (701). Also, since the indent value varies depending on whether the current node is a multiple control statement, it is determined whether the current node is a single control statement (702), and in the case of a single control statement, basic indentation processing is performed (703). If it is not a single control statement (ie, multiple control statements), indentation is performed on the beginning and the end of the control statement, and thus a special type of indentation processing is performed (704). Here, if multiple control statements such as IF statement or CASE statement overlap, the abstract syntax tree structure is more complicated than general control statement. Therefore, indentation should be processed considering various state values. It also searches for nodes one by one from the beginning of the linked list and gives indents for each.

7 is a detailed processing flowchart of a diagnostic result output step for the control flow structure of FIG. 3.

First, it determines whether or not the linked list is null and terminates if it is null (801). Otherwise, it modifies each node of the linked list consisting of the information of modalities, blocks, and execution statements that affect control. Read and indent according to the read indent value of the node to visually output the nesting relationship between each node, and returns to the step 801 again to repeat until the linked list is null (802).

According to the present invention, a module and a block in a unit program are processed, an execution statement in a module and a block is processed, an indentation process is performed for each node, and an output is output for each node of the linked list. By providing a control flow display method for the fill language, the visual flow of the visibility structure and concurrency of the input fill source program and the nesting relationship between the execution statements enables the developer to visually indent the overall flow and execution statements of the program. By clearly understanding the relationship between, it is possible to write more reliable chilling program and improve the quality of software through control flow analysis.

Claims (5)

In the display method of the control flow for analyzing the program execution order for the CHILL language for programming the exchange software, A first step of determining whether 20 unit program searches have been completed; A second step of reading one unit program information if not completed in the first step; A third step of traversing the abstract syntax tree associated with the unit program read in the second step, searching for information of the module and the block in the unit program constituting the abstract syntax tree and storing the information in a linked list; A fourth step of searching for only elements influencing the control of the execution statements within the module and the block found in the third step, storing the information in a linked list, and returning to the first step to repeat the steps; A fifth process of setting an indent value for each node when 20 unit program searches are completed in the first process; And a sixth process of sequentially reading each node having an indent value set in the fifth process, visually indenting the control flow structure information of the program, and outputting the list in the form of a list. Way. The method of claim 1, The third step may include: a first step of defining an group name for a current node by searching an abstract syntax tree from the beginning and checking whether a node type of each node is a module and a block; A second step of generating and storing a node to form a connection list of information about a start point of the current node of the first step, and inserting the point into the connection list; And a third step of generating a node to be configured as a linked list of information about the last point and inserting the node into the linked list. The method of claim 1, The fourth step includes: a first step of determining whether the node entry is null and ending if it is null; A second step of determining whether a node entry is a non-terminal if not null in the first step; A third step of searching for only elements that affect control when the non-terminal is used in the second step, and generating a node for the entry and inserting the node into the connection list; After performing the third step or in the second step, if the node entry is not a non-terminal, the node is reset to a sibling entry to search for sibling nodes in the abstract syntax tree in order to search for nodes that affect the rest of the execution. And a fourth step of returning to said first step and repeating said steps until a node entry becomes null. The method of claim 1, The fifth process includes: a first step of searching for a current node and depth information about the current node in a connection list; A second step of determining whether the current node found in the first step is a single control statement; A third step of performing basic indentation processing in the case of the single control statement in the second step; And a fourth step of performing a special type of indentation processing when the second step is not a single control statement (ie, multiple control statements). The method of claim 1, The fifth process includes: a first step of determining whether the linked list is null and ending if it is null; If the first step is not null, each node of the linked list composed of the information of the module, the block, and the execution statements affecting the control is read in sequence, and indented according to the read indent value of each node, and the nodes are read. And a second step of visually outputting a nested relationship of the and returning to the first step and repeatedly performing a connection list until null.

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