JPH07239787A - Extraction device for information from parsing tree - Google Patents

Abstract

PURPOSE:To easily extract information from a source program of any language and to make the correspondence relation between the original source program and the extracted information clear. CONSTITUTION:At a request given by one of tools 9, 10..., an instruction extracting means 6 extracts necessary information from the parsing tree of the object language, converts only the extracted information to a common format which does not depend upon the language of the extracted information, and supplied it to the use currently in use. When a source program of any language among 7, 8... is handled, information on the common format among respective languages is supplied to the tool to enable the languages to be processed by the one tool, the correspondence relation between the parsing tree and extracted information is prevented from becoming unclear as a result of the conversion to the common format, and the result of the processing into an object source program by the tool is easily reflected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information extraction device from a syntax analysis tree, and is particularly suitable for use in software development for analyzing a source program.

[0002]

2. Description of the Related Art Conventionally, when developing application software for analyzing a source program, an existing source program is parsed, and information obtained as a result of this analysis is analyzed by various tools (for example, call graph). It is performed by a generator or a data flow analyzer). Such software is intended for source programs in various procedural languages.

As described above, in order to extract necessary information from the analysis results of source programs of various languages and to enable a tool to perform a predetermined process by using this information, conventionally, the following is mainly used. Two methods are adopted.

That is, the first method is a method of creating a program analysis system for each language. For example,
When the target source program has two languages, the first language and the second language, a program analysis system for the first language and a program analysis system for the second language are created respectively. Is.

The second method is to translate the analysis result of the source program of each language into an intermediate representation common to each language,
A method is to perform processing such as analysis with a tool using this intermediate representation.

[0006]

In the first method described above, a tool corresponding to each language is created for each language, so that even detailed information depending on each language can be handled. However, since it is necessary to create a tool for each language, there is a problem in that it costs a lot. In addition, when the function of the tool is expanded, it is necessary to correspond to each language, so that there is a problem that it takes a lot of time to expand the function.

On the other hand, in the second method, the analysis result of the source program of each language is translated into an intermediate representation common to each language, so that a common tool is created regardless of the target language. You can Therefore, the problem described above does not occur in this second method.

However, in the second method, all the analysis results of the source program are collectively translated into the intermediate representation. For this reason, it becomes difficult to make correspondence between the original source program and the intermediate expression after translation. For example, it is necessary to find out which part of the original source program a certain part of the intermediate expression corresponds to, It was difficult to convert the original source program according to the processing result.
In addition, there is a problem that information of a part peculiar to each language is lost during the translation into the intermediate representation.

The present invention has been made to solve such a problem, and makes it possible to easily extract information from a source program of any language, and at the same time, the original source program and its intermediate representation. The purpose is to be able to clarify the correspondence relationship with.

[0010]

An information extraction device from a syntax analysis tree of the present invention is a tool for extracting information from a syntax analysis tree of a source program and performing a predetermined process,
In the information extraction device from the syntactic analysis tree that provides the extracted information, a plurality of syntactic analysis provided for each of the programming languages in order to create the syntactic analysis tree from the source programs described in various programming languages. Means and the syntax analysis tree output from each of the plurality of syntax analysis means according to a request from the tool, and extract the information from the syntax analysis tree of the programming language targeted by the tool. An information extracting means for converting information into a format common to each programming language and supplying it to the tool is provided.

Another feature of the present invention is to access a plurality of parse trees provided for each of the programming languages in order to extract information from the parse trees output from the plurality of syntax analysis means. Means and a parse tree access means corresponding to the programming language targeted by the tool from among the plurality of parse tree access means according to a request from the tool. The information extracting means includes a language switching means for switching the access means and a conversion means for converting the information extracted by the syntax analysis tree access means selected by the language switching means into a format common to each programming language. Is configured.

Still another feature of the present invention is that whether or not the information extracted by the parse tree access means selected by the language switching means is converted into a format common to each programming language is selected. The selection means is provided.

[0013]

Since the present invention comprises the above technical means, regardless of which programming language source program is targeted, the tool is provided with information in a common format independent of the programming language, and a plurality of programming languages are provided. It is possible to process a language source program with one tool. Further, only the information extracted from the corresponding parse tree in response to the request from the tool is converted into the intermediate format, so that the correspondence relationship between the extracted information and the parse tree becomes clear.

According to another feature of the present invention, a plurality of programming languages can be processed by one tool, and the programming language to be processed can be dynamically selected. Efforts to extract necessary information from source programs in various languages are reduced.

According to still another feature of the present invention, among the information extracted from the parse tree, the information specific to the programming language may not be converted into the intermediate format. In addition, the inconvenience of losing the information specific to the programming language is eliminated.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a main configuration of a program analysis system to which an information extraction device from a syntax analysis tree according to this embodiment is applied.

In FIG. 1, reference numeral 1 denotes an information extraction device from a syntax analysis tree according to this embodiment, which is a syntax analysis means 2 for a first language, a syntax analysis means 3, for a second language, ... .. for storing the parse tree given by each of the means 2, 3, ... For storing the parse tree for the first language 4, the parse tree storage means for the second language 5 ,. And means 6.

The syntactic analysis means 2, 3, ... Are provided in correspondence with the source program 7 of the first language, the source program 8 of the second language ,. The program 7, 8, ... Is analyzed to create a syntax analysis tree for each language. Here, the syntactic analysis tree is a tree structure representing the structure of the source program. Also, as the language of the source program,
For example, FORTRAN, C, COBOL, PASCA
L, BASIC, etc.

Further, the above-mentioned information extracting means 6 responds to a request given from each tool such as the call graph generator 9, the data flow analyzer 10, ... Which extracts necessary information from the syntax parse tree stored in, converts it into a format common to each language independent of the language, and supplies it to the call graph generator 9, the data flow analyzer 10 ,. Is. The information extracted from the syntax analysis tree is the above tools 9, 1
It varies depending on the request from 0, ....

The information extraction means 6 has a function of sequentially tracing the nodes of the parse tree, a function of obtaining a variable whose value is referred to or a variable to which a value is assigned, and a node of the parse tree corresponds to which part of the source program. It has a function to ask for Then, these functions are executed in response to a request given from each tool such as the call graph generator 9, the data flow analyzer 10, ..., By this, necessary information is extracted from the parse tree. There is.

The call graph generator 9 is for generating a call graph by analyzing and processing the program using the information extracted from the source program. For example, the call graph generator 9 receives information about where a function or procedure in a source program is defined and where it is called from the information extracting means 6, and obtains a calling relationship between the functions and procedures.

The data flow analyzer 10 is for analyzing the flow of data in the program. For example, the data flow analyzer 10 receives from the information extraction means 6 information about where a variable in the source program is defined and where it is used, and analyzes the data flow.

Next, FIG. 2 shows a concrete configuration of the above-mentioned information extracting means 6. In FIG. 2, reference numeral 11 is a parse tree access unit of the first language, and each tool 9, 10,
This is for accessing the parse tree storage means 4 of the first language in response to a request given from ... and extracting necessary information therefrom.

The parse tree access means 11 of the first language has a parse tree moving / detecting section 11a, an information extracting section 11b, and a parse tree changing section 11c. The parsing tree moving / detecting unit 11a sequentially follows the nodes of the parsing tree of the first language,
It detects which part of the original source program the parse tree corresponds to. The parse tree moving / detecting unit 11a holds information indicating a state such as how the parse tree is followed and which part is being accessed now.

Further, the information extracting unit 11b extracts necessary information from the syntactic analysis tree of the first language in response to a request given from each of the tools 9, 10, .... For example, the information extraction unit 11b extracts information such as where the function or variable is defined in the source program and where it is called from the syntax analysis tree of the first language. Further, the parsing tree changing unit 11c includes the tools 9, 1
This is for changing the target parse tree in response to a request from 0, ....

Next, 12 is a selection means, which is the first
This is to select whether or not to convert the information extracted by the syntax analysis tree access unit 11 of the language into a format common to each language. Here, the selection is made such that the information of the part peculiar to each language is not converted into the common format, but other information is converted. Reference numeral 13 is a common format conversion means for converting the information provided by the selection means 12 into a common format independent of the programming language.

As described above, in this embodiment, the necessary information is extracted from the parse tree of the first language by the parse tree access means 11, the selection means 12 and the common format conversion means 13. A configuration is provided for converting this into a common format. The second language is also configured in the same manner as the above configuration. That is, the parse tree access unit 14, the selection unit 15, and the common format conversion unit 16 are configured to extract necessary information from the parse tree of the second language and convert it into the common format. ing. The same applies to other languages not shown.

Next, 17 is a language switching means, which selects the parse tree access means for that language from among the parse tree access means 11, 14, ... In accordance with the target programming language. To do. Then, after selecting one of the parse tree access means, the language switching means 17 functions as an interface between the parse tree access means and the tool currently being used.

Next, the operation of the information extraction device from the syntax analysis tree according to the present embodiment configured as described above will be described with reference to a specific example. Here, a case where a call graph is generated from a source program of two languages of C language and FORTRAN will be described as an example. That is, the first language source program 7 shown in FIG. 1 is a C language program, and the second language source program 8 is FORTR.
Suppose it is an AN program.

In this case, it is assumed that the C language source program 7 and the FORTRAN source program 8 include those shown in FIGS. 3 and 4, respectively. These source programs 7 and 8 are converted into syntax analysis trees of respective languages by the syntax analysis means 2 and 3 of the respective languages. Then, these parse trees are stored in the parse tree storage means 4 and 5 for each language.

That is, the C language source program 7
Is converted into a syntax analysis tree by the syntax analysis means 2 of the first language, and the syntax analysis tree is stored in the syntax analysis tree storage means 4 of the first language. Further, the FORTRAN source program 8 is converted into a parse tree by the parse tree 3 of the second language, and the parse tree is stored in the parse tree storage 5 of the second language. The parse tree stored in this way depends on each programming language, and its structure differs depending on the programming language.

By the way, in order to generate a call graph, in the C language, it is necessary to find out which function call is included in which function definition. Also, FO
In RTRAN, which program definition, subroutine definition, which subroutine call in function definition,
Need to ask if there is a function call.

As described above, due to the difference in the structure of each programming language, the information required when generating a call graph differs for each programming language.
Therefore, the information extraction means 6 performs a predetermined process on the information extracted from the syntax analysis tree of each language, so that the above-mentioned subroutines and functions are expressed as a common format procedure that does not depend on the language. .

For example, the definition of function a, the definition of function b, and the function c in the C language source program shown in FIG.
, The definition of procedure a, the definition of procedure b,
It is expressed as the definition of procedure c. Further, the definition of the program c, the definition of the subroutine a, and the definition of the function b in the source program of FORTRAN shown in FIG. 4 are expressed as the definition of the procedure c, the definition of the procedure a, and the definition of the procedure b, respectively.

By doing so, the call graph generator 9 can obtain the FO from the C language source program 7.
The call graph can be generated by taking out necessary information from the RTRAN source program 8. This eliminates the need to create a call graph generator corresponding to each language for each language, thus reducing costs.

Further, as described above, since the call graph generator can be created in a form independent of the programming language, when adding the target programming language, it is only necessary to create the parse tree access means for that language. so,
It can be added to the call graph generator without any modification, and the labor can be reduced.

Here, for example, the operation of extracting necessary information from the C language syntax analysis tree and converting the extracted information into a common format will be described with reference to FIGS. 1 and 2.
First, the call graph generator 9 sends a request to the information extracting means 6 to target the C language. Information extraction means 6
Upon receipt of this request, the language switching means 17 in the above section selects the parse tree access means 11 of the first language from the parse tree access means 11, 14 ,.

Next, when the call graph generator 9 issues a request to the information extracting means 6 for the procedure definition and call information, the request is sent via the language switching means 17 to the first language. Parsing tree access means 1
Given to 1. Then, the parse tree access unit 11 of the first language analyzes the C parse tree stored in the parse tree storage unit 4 of the first language to extract necessary information.

The information thus extracted is selected by the selecting means 12
Given to. Then, whether or not the given information is peculiar to the C language is discriminated by the selecting means 12, and only the information not peculiar to the C language is given to the converting means 13 to the common format so that the common information independent of the language is obtained. Converted to format.

For example, the following information is extracted from the syntax analysis tree of the C language source program shown in FIG. -There is a definition of function a.・ Function b is defined. There is a definition of the function c, in which there is a call to the function a. There is a call to function b.

In this case, the above information is given to the common format conversion means 13 and converted into the following common format information which does not depend on the programming language.・ Procedure a is defined.・ Procedure b is defined. There is a definition of procedure c, in which: -Call of procedure a. There is a call to procedure b.

Next, the information converted into the common format as described above is sent to the call graph generator 9 via the language switching means 17. Then, the call graph generator 9 performs a predetermined process on the basis of the information thus sent, thereby generating a call graph as shown in FIG.

As described above, in the information extraction device from the parse tree according to the present embodiment, not all the information extracted from the parse tree is converted into the intermediate format as in the conventional case, but the request from the tool is issued. According to the above, only the information extracted from the corresponding parse tree is converted into the intermediate format. Therefore, it becomes possible to easily determine which part of the parse tree the extracted information corresponds to.

Therefore, for example, it is possible to add a line number or a part of the source code to the result of processing by the tool and output it, or to find out where the parse tree is when changing the parse tree. It will be easier.

Further, when converting to the intermediate format, since the conversion is not performed for the part peculiar to the programming language, there is no inconvenience that the information of the part peculiar to the language is lost during the conversion. be able to.
As a result, it is possible to reliably extract the necessary information from the target source program.

In order to process the information of the language-specific part which has not been converted into the intermediate format, a tool dedicated to that language (for example, the information of the part specific to the first language is processed). Tools, tools for processing information specific to the second language, etc.) must be provided and processed by these tools. However, even if these tools are provided, the number of tools as a whole is significantly smaller than that in the conventional technique in which a tool corresponding to each language is provided for each language.

Furthermore, according to the information extraction device from the syntax analysis tree according to the present embodiment, the syntax analysis trees of a plurality of programming languages can be processed by one tool, and the syntax analysis tree of which language is processed. Since it is possible to dynamically select whether or not to do so, it becomes possible to easily extract information from the syntactic analysis tree, which can improve the efficiency of the development work of the program analysis tool. Moreover, since it is not necessary to change the tool used for each language, it is very convenient for the operator.

[0048]

As described above, according to the present invention, necessary information is extracted from the syntax analysis tree of the target programming language in response to the request from the tool, and this is converted into a common format independent of the language, and then the above Since it is supplied to the tool, no matter what programming language is used, common format information independent of language is given to the tool, and source programs of multiple programming languages are processed by one tool. You will be able to. Therefore, the tool can be created in a form independent of the programming language.

Further, since only the information extracted from the corresponding parse tree is converted into the intermediate format in response to the request from the tool, which part of the parse tree corresponds to the extracted information. Can be easily determined, and the result of processing by the tool can be easily reflected in the original source program.

According to another feature of the present invention, a plurality of programming languages can be processed by one tool, and a programming language to be processed can be dynamically selected. The effort for extracting information from various programming languages can be reduced and the information can be easily extracted. For example, the work efficiency of the development of a program analysis tool can be improved.

Further, since the tool can be created in a form independent of the programming language, it is not necessary to make any changes to the tool. As a result, when adding a target programming language, it becomes possible to add the target programming language simply by creating a parse tree access means for that language, and the effort when adding the programming language. Can be reduced.

According to another feature of the present invention, among the information extracted from the parse tree, the information peculiar to the programming language is not converted into the intermediate format. In addition, it is possible to eliminate the inconvenience that the information peculiar to the programming language is lost, and it is possible to reliably extract the necessary information from the original source program.

[Brief description of drawings]

FIG. 1 is a block diagram showing a main configuration of a program analysis system to which an information extraction device according to an embodiment of the present invention is applied.

FIG. 2 is a block diagram showing a specific configuration of information extraction means.

FIG. 3 is a diagram showing an example of a source program written in C language.

FIG. 4 is a diagram showing an example of a source program written in FORTRAN.

FIG. 5 is a diagram showing a call graph generation result.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Information extraction device 2 1st language syntactic analysis means 3 2nd language syntactic analysis means 4 1st language syntactic analysis tree storage means 5 2nd language syntactic analysis tree storage means 6 Information extraction means 7th 1 language program 8 2nd language program 9 Call graph generator 10 Data flow analyzer 11 1st language syntax analysis tree access means 11a Movement / detection unit of syntax analysis tree 11b Information extraction unit 11c Syntax analysis Change part of tree 12 Selection means 13 Conversion means to common format 14 Parsing tree access means of second language 15 Selection means 16 Conversion means to common format 17 Language switching means

Claims (3)

[Claims] 1. An information extraction apparatus for extracting information from a syntax analysis tree of a source program, which provides the extracted information to a tool adapted to perform a predetermined process, in various programming languages. A plurality of parsing means provided for each programming language for creating a parsing tree from the described source program, and a parsing tree output from each of the plurality of parsing means are output from the tool. Information extraction means that checks according to a request, extracts information from a syntax analysis tree of a programming language targeted by the tool, converts the extracted information into a format common to each programming language, and supplies the converted information to the tool. An information extraction device from a syntax parse tree, comprising: 2. The information extraction device from a syntax analysis tree according to claim 1, wherein the information extraction means extracts each information from the syntax analysis tree output from each of the plurality of syntax analysis means. A plurality of parse tree access means provided for each language and a parse tree access means corresponding to the programming language targeted by the tool from among the plurality of parse tree access means are provided in response to a request from the tool. Language conversion means for switching the target parse tree access means, and the information extracted by the parse tree access means selected by the language switch means is converted into a format common to each programming language. An information extraction device from a syntactic parse tree, which is configured by a conversion means to a common format. 3. A selection means for selecting whether or not to convert the information extracted by the parse tree access means selected by the language switching means into a format common to each programming language. An apparatus for extracting information from a syntax analysis tree according to claim 2.