JPH01237737A - System for supporting flag identification - Google Patents

Abstract

PURPOSE:To improve efficiency of the test of a software by preparing the list of a variable, which is referred to only by a conditional statement or an assignment statement, to an inputted program and extracting a flag from the variable which is decided as a marker. CONSTITUTION:A variable list (..., X, Y,...), which is referred to only by the conditional statement or assignment statement, is prepared by a variable list producing part 102 to the inputted program. For the variable X of the variable list, a referring spot (Y=X-4) is investigated by a arrivable defining set extracting part 103, named as a eta and stored to an REF list. Next, the eta is fetched and an RD (eta, X) is obtained by an analyzing means 108 and stored in an RD list. Whether there is the conditional statement or not is decided by a deciding part 104. Then, the X is referred in a second conditional branch and a conditional function is obtained. The RD (eta, X) is fetched and whether the definition of the flag to the X is satisfied or not is investigated. After that, the X is decided as the marker and a variable Y, which is defined with the X is obtained as the flag in a flag extracting part 105 and stored in a flag list. Then, the Y is erased from the variable list.

Description

[Detailed Description of the Invention] [Summary] Support for efficiently performing software testing, etc., regarding a flag identification support method for identifying variables used as flags among variables in a procedural language program. The purpose of this program is to provide a variable list generator that creates a list of variables that are referenced only by conditional statements or assignment statements for an input program, and a a reachable definition set extraction unit that obtains a set of reachable definitions; a marker final determination unit that examines whether the set of reachable definitions is divided into disjoint subsets by a certain conditional statement; a flag extraction unit that creates a list of variables to be used as flags from variables determined to be markers;
and an output processing unit that outputs the list of flags, and is configured to support extraction of variables used as flags in the input program.

[Industrial application field]

The present invention relates to a software testing method, and more particularly to a flag identification support method for identifying variables of a procedural language program that are used as flags.

The present invention is a system for supporting flag identification work using a computer, and aims to make flag identification more efficient by using data flow analysis, which is an existing technique.

[Prior art and problems to be solved by the invention] When trying to understand a created program for software testing or maintenance, for example, the need to delete, change, or add functionality, it is difficult to understand that a certain variable is a flag. Identification is important to facilitate understanding tasks. Previously, this work had to be done by the person in charge directly reading the program and relying on their own knowledge and background, which took time and effort, and the content of the work was heterogeneous.

An object of the present invention is to provide a support method for efficiently performing software testing.

[Means and effects for solving the problems] Before explaining the present invention in detail, the definition of a flag will be clarified. However, in the following we will exclude flags that are used across multiple programs. That is, the present invention targets only flags that are used locally within a program and have no reference relationship with other programs. Basically, flags are used to control branching of processing at other (later) points in accordance with the processing at a certain point in the program.

In other words, flags are control variables used only to control branching in a program, and have no other meaning. A flag is used in conjunction with a marker variable to store the processing at a certain point in a program, but the marker itself can also serve as a flag.

Usually both are the same.

Next, we will give the definition of f'.

・Variable X is defined by variables AH, ..., A6 (for example, X: ” AI + 2 At + 3
As in A3, AI, ..., X depending on the value of A
An assignment statement that determines the value of is called a definition of X), then this can be expressed functionally as

A) I will write it as follows.

-Hereinafter, the conditional function of a conditional statement is a function that is true (T) when the conditional expression in the conditional statement is true, and false (F) when it is not true.

For example, the conditional statement "if X+2Y>Othen...else..."
The conditional function of is .

・Variable X is indirectly referenced as Y:=f(X,
This means that a variable defined using X (Y in this case), such as Z'), is referenced.

Here, the conditions for determining that a variable used in a program in the present invention is a flag are found below.

[Definition 1] Variable X is a marker (MK).

(1) X is referenced only in a conditional statement or an assignment statement in the program (this referenced node is assumed to be η).

(2) For the reference in (1), X has two or more different reachable definitions (let this be RD(η, X>)).

(31RD(η,
. This Definition 1 (3) can be found more specifically as Definition 2.

[Definition 2) RD(η, X) = (X: =X
(i) (Al(ri,...A, U)); i =
1°..., n), RD(η, X) is divided into subsets that can be determined to be different from each other by a certain conditional statement.

+l) There is a conditional statement that refers to X directly (for example, C(X)) or indirectly (for example, C(W); w== (X)). In this case, the conditional function of this conditional statement is C(X,
Yl, ..., Yi).

However, if X is indirectly referenced in the conditional statement,
There is a variable (let W) defined by X, and W:
=g (X, B, . . .

Bs). At this time, the conditional function is C(g (X, B,, ・ −・, Bs)
, Y.

・ ・ ・, Yi), but since there is no essential effect, C is used for simplicity.
Consider only the case of (X, Y, . . . , Yz).

(21X(7) Definition X , =)((i) (A,
(i) ,...,.

A, (i)), the domain of the function X(') (i.e. all Ak'' (K=1. . . .

set of possible combinations of possible values of m)) as don(X
) (dom; area), all X<=+
(i = 1. . . +, n)! 11: In contrast, the following holds true.

Y++...When the possible values of YL are arbitrarily fixed (these are yl,...yz), C(X (direct)
Eyes (mu'+71+ ..., y, c) = constant forf
"Kdom(X") +3)Y,... When the possible values of Yfi are fixed arbitrarily, C(X"ゝ (Word (11), y,...

yz)≠C(X ” (a ”) r 7 r
+...

There exist i and j (i≠j) such that y□).

[Definition 3] Variable X is a flag.

Either X is MK and there is a conditional statement that directly references it, or there is a conditional statement that is defined by MK and directly references X.

Definition 1 is a definition of a variable used as a marker in the program. In many cases, the marker itself and the flag match; for example, M in FIG. 2(a) is a flag and is a remarker. For example, in the case of the example shown in Figure 2), Ml, M2
is a marker but not a flag, and F is not a marker but is considered a flag.

Definition 2 is a formulation of one of the properties of a marker (definition 1131).

Definition 3 is the definition of a flag.

Next, a functional block diagram of the present invention is shown in FIG.

The present invention inputs a specified program (101) and outputs a list of variables used as flags within the program (107).

The variable list generation unit 102 creates a list of variables that are referenced only by conditional statements or assignment statements among all (local) variables of the read program (Definition 1 (11)
. This list is called a "processing list". The first element (variable) is extracted from the processing list, the processing after the reachable definition set extraction unit 103 is executed, and when the processing is completed, the next element is extracted and the same process is repeated.

The reachable definition set extraction unit 103 is for checking definition 2 (2). This is variable list generator 1
02 is input, and by using the data flow analysis means 1O8, which is an existing technique, a set of definitions of X that can reach the location where the variable (denoted as X) is referenced is obtained. When this set consists of two or more elements (definition [2)], the marker final determination unit 10
4 and subsequent processes are executed, and if not, the process related to X is ended.

Here, the definition of X that can reach a certain point η in the program (
Assignment statement) means that there exists a path from its definition to η,
A definition in which there is no other definition of X on that path. For example, the set RD(η4.X) of definitions of X that can reach 44 in FIG.
+Y).

FIG. 4 shows a processing flow diagram of the reachable definition set extraction unit. This process will be explained below with reference to FIG.

The change X(2) extracted by the variable list generation unit 102
All references to 01) are checked, given a name to identify the position in the program, such as a line number, and stored in the REF list (202).
. For example, in FIG. 3, the REF list is -(η3.η4).

Extract the first element η from the REF list and set RD (77,
X) is determined (203).

If the number of elements in RD(η,
05).

Otherwise, store RD(η,
) Repeat the same thing.

Next, the marker final determination section 104 will be explained using FIG. 5, which is a processing flow diagram thereof. Marker final judgment section 10
4 is a part that performs processing for checking (3) of Definition 1 (ie, Definition 2).

First, it is determined whether there is a conditional statement that directly or indirectly refers to the variable X of interest (303), and if there is no conditional statement, the process regarding X is terminated and the reachable definition set extraction unit 1
Return to 03 (302).

Here, referring to X indirectly means Y:=f(X, Z"
) refers to the case where a variable Y defined using X is referenced.

Next, a conditional function C (X, Y+, Y2, . . . , Yl) regarding the conditional statement is obtained from the conditional statement (304).

Let η be the position of the conditional statement in the program. shall be.

From the input RD list I-(301) to the first element (RD
(let η, X>) is extracted (305).

Furthermore, the first element (x, = x (
i) Extract (A, (''), . . . , a, , (1)) (306).

It is checked as follows whether (2) of Definition 2 holds for this X(i) (307).

In the program, X , = X (i) (A,
Let η(1) be the location (definition location) where +ri,... ),, (1) ) exists.

A. Tit by a support method for estimating possible values of program variables (hereinafter abbreviated as value estimation method).

..., A, +i), find all possible values of η(i), and for all combinations of those values (i.e., all a(a)εdomX(")
) C(X” (a ”’ ) + )’+ ,...
yA)...(1) Calculate and check whether all the calculation results match. However, C is a conditional function, y++ ..., y
is Y3. . . . is fixed to a value that can be taken at ηゎ of YL. Ding (correct) is a (i) = (a , (ri, a %
il, , ・t, a,
(5) ) katsu a lC1' + ” ' + a
m ″) are A and (t ), respectively.

. . . is the possible value of Ai (iゝ).In reality,
When X is a marker, the definition of X is often just a constant (X), and equation (1) becomes C(x, y, . . . , yl) for that definition and remains unchanged. Therefore, in this case, definition 2 (2) regarding X
It can be seen that (307) is easily established.

A similar check is performed for all elements of RD(η, X) (definitions of X that can reach η) (309).

Next, each definition of X X: = X (i) (...
), does Definition 2 (2) hold for X?
Executed when checking (307), it is checked whether (3) of Definition 2 holds true using the result of the calculation of equation 11. If it holds, X is determined to be a marker and it does not hold. If not, the process regarding X is ended and the process returns to the reachable definition set extraction unit 103 (30B).

If it is determined that X is a landmark (marker) through the process of the marker final determination unit 104 as described above, then the flag extraction unit 105 is executed.

The flag extraction unit 105 receives the marker variable X and checks whether X is directly referenced in a certain conditional statement in the program. If it is directly referenced, X is determined to be a flag and is stored in the flag list. When X is not directly referenced by a conditional statement, the assignment statement in which X is referenced is checked in the program, the variable to which it is assigned (the left side of the assignment statement) is stored as a flag in the flag list, and then deleted from the variable list.

With the above, the processing related to X is completed, and the process returns to the reachable definition set extraction unit 103 to repeat the same processing.

After processing is completed for all elements (variables) of the variable list generated by the variable list generation unit 102, the output processing unit 1
06, the flag list is output in an appropriate format.

〔Example〕

The program flowchart of the embodiment of the present invention shown in FIG. 6 will be described with reference to FIGS. 1, 4, and 5.

The process of the variable list generation unit 102 is executed for the input program (Fig. 6), and the variable list (...,
Y, ...) is created.

For each element of the variable list, reachable definition set extraction unit 1
It is assumed that the processes after 03 are executed one after another, and now the process regarding variable X is executed.

The variable X is sent to the reachable definition set extraction unit 103 (20
1), you can look up the references. The reference point for X in the program of this example is Y knee X-4, so
Name this η and store it in the REF list (
202). REF list=(η).

Next, η is extracted from the REF list and RD(η, x) is obtained using the data flow analysis means 108 (20
3), RD (η, X)=(X:=1, X:=51.

Since the number of elements of RD(η,X) is 2 or more (204), it is stored in the RD list (206).

RD list=RD (η, X).

Since the REF list is empty (20?), the process is transferred to the marker final determination unit 104.

The marker final determination unit 104 first determines whether there is a conditional statement that directly or indirectly refers to X (
303), X is indirectly referenced in the second conditional branch.

Therefore, find the conditional function regarding this conditional statement (304
).

The condition function is It is.

Extract the first element RD (η, X) from the RD list (3
05).

Next, the first element X:=1 is extracted from RD(η,X) (306). This definition is a constant definition, and since the definition of X does not include any variables, X always takes the same value (i.e. 1), so C(1) = F... (A)
Therefore, definition 2 (2) holds for X (307)
.

At this time, RD(η,
Similarly, C(5)=T ・ ・ ・ ・
From (a), definition 2(2) holds for X (307
).

From (a) and (b), definition 2 (3) holds, so (3
10), determines that X is a marker (311).

Next, processing is transferred to flag extraction section 105. The flag extraction unit 105 inputs the marker variable X and checks to see if there is a conditional statement that directly refers to X.
The variable Y defined by X is stored as a flag in the flag list, and Y is deleted from the variable list.

The processing related to X is thus completed, and the process returns to the reachable definition set extracting unit 103 to perform the same processing until there are no more variables, and finally outputs the flag list and completes the entire processing.

〔Effect of the invention〕

According to the present invention, when testing a program in a procedural language, work efficiency is significantly improved compared to conventional manual testing.

[Brief explanation of the drawing]

Fig. 1 is a functional block diagram of the present invention, Fig. 2(a) and (bl are marker discrimination diagrams, Fig. 3 is an example of a flow for explaining the present invention, and Fig. 4 is a reachable definition of the present invention). Figure 5 is a processing flow diagram of the set extraction unit, Figure 5 is a processing flow diagram of the marker final judgment unit, and Figure 6 is an example diagram of the input program.101... Input program, 102... Variable list generation unit, 103. ... Reachable definition set extraction unit, 104... Marker final judgment unit, 105... Flag extraction unit, 106... Output processing unit, 107... Output list, 108... Data flow analysis means, 109...Means for estimating possible values of variables.

Claims (1)

[Claims] A variable list generation unit (102) that creates a list of variables that are referenced only by conditional statements or assignment statements for an input program (101); A reachable definition set extraction unit (103) that obtains a set of reachable definitions for a variable, and checks whether the above set of reachable definitions can be divided into disjoint subsets by a certain conditional statement. It has a marker final determination unit (104), a flag extraction unit (105) that creates a list of variables used as flags from variables determined to be markers, and an output processing unit (106) that outputs the list of flags. , a flag identification support method that supports extracting variables used as flags in an input program.