JPH06214764A - Influence analysis device by correction of program - Google Patents

Abstract

PURPOSE:To provide an influence analysis device by means of the correction of a program which can precisely recognize a dependent relation between variables without judging that influence is given even if it is not actually given. CONSTITUTION:A calculation route restriction means 15 detecting a calculation route not executed is provided. The calculation route restriction means 15 preserves a restriction condition with respect to the variable deciding the truth or false of a logical expression in a condition sentence when a system passes through the condition sentence bringing branch, monitors the presence or absence of the change of the value of a variable in a section to the condition sentence which appears later in the calculation route, inspects the restriction condition of the condition sentence which appears later and sequentially judges that some of branches of the condition sentence appearing later is not executed by following the calculation route when the restriction condition of the later condition sentence can uniquely be decided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an influence analysis device for analyzing the influence of a modification made on a program.

[0002]

2. Description of the Related Art When a computer program is modified, some variables appearing in each statement in the modified program are affected by the modification. For example, if you modify the place where "a: = 1" in a certain statement to "a: = 5", when the statement that is executed after this statement says "d: = a", the variable The influence of the program modification affects d. Here, a value that is determined by a series of statements that is different from that before correction is defined as one that is affected by the correction.

Conventionally, as a technique for analyzing such an influence due to a modification applied to a program, there is one using a calculation path detecting means and an influence analyzing means. FIG. 1 is a block diagram showing the configuration of an apparatus (impact analysis apparatus) that has been used conventionally and analyzes the effect of modifying a program. The influence analysis device 50 is connected to an analysis target program holding device 51 that stores a program to be analyzed, and has a calculation path detection unit 52 that detects the execution order of the programs and an influence that analyzes the influence of the correction. It is composed of an analysis means 53 and a control means 54 for controlling the whole operation.

First, the definitions of terms are shown below. -Program calculation path In a procedural language program, the sequence of statements obtained by following the execution order according to syntax information is defined as the program calculation path. FIG. 2 shows an example of a program including a conditional statement. The procedure calc_1 in this program includes a calculation path represented by ST11 → ST12 → ST13 → ST14 → ST15. Further, the Console_in and Console_out procedures are procedures for inputting data from an input device and outputting data to an output device, respectively.

In the description of this specification, what is represented by "ST" + numeral indicates a statement. The illustrated program is an Algol language and is similar to the Pascal language. A procedure is called by the call statement, and the assignment relationship is indicated by ": =". Also, the end of the if clause is indicated by "fi" instead of "endif". -Dependency between variables When the value of another variable or constant in the same statement is referenced to define (assign) a value to a variable in a statement, the defined variable is the referenced variable or constant. Call it dependent on. We define this as having a reference definition dependency from the referenced variable or variable defined from a constant. For example, in the statement ST13 in the procedure cal_1 in FIG. 2, the variable s defined from the referenced variable q has a reference definition dependency relationship.

Further, when referring to a value of a variable in a statement, the variable to be referred to is defined when the value to be referred to is defined in another statement preceding the statement on a calculation path. Is called dependent on the variables defined. We define this as having a definition reference dependency from the defined variable to the referenced variable. For example, in the procedure calc_1 in FIG. 2, the statement ST13
There is a definition reference dependency from the variable s defined in step S15 to the variable s referenced in step ST15.

Further, the reference definition dependency relationship, the definition reference dependency relationship, and the relationship between variables obtained by combining these are defined as the dependency relationship between variables. For example, in the procedure calc_1 in Figure 2, the statement ST
Reference definition dependency relationship from the variable q referenced in 13 to the variable s defined in ST13, definition reference dependency relationship from the variable s defined in ST13 to the variable s referenced in ST15, and referenced in ST15 By combining the reference definition dependency relation from the variable s referred to in ST15 to the variable u defined in ST15, the dependency relation between the variables from the variable q referred to in ST13 to the variable u defined in ST15 is obtained. -Affects When the program is modified, it is considered that the effect of the modification will be exerted on the variables that appear in each statement in the modified program and whose values are determined by a series of statements different from those before the modification. Define.

Next, the conventional influence analyzer 5 shown in FIG.
0 calculation path detection means 52 and influence analysis means 5
The functions that 3 should perform will be described. -Calculation route detecting means 52 The calculation route detecting means 52 obtains a calculation route which may be actually executed. That is, each time a conditional statement (if statement) appears in the calculation path, the calculation path is obtained by tracing the sequence of statements corresponding to each branch. For example, for the procedure calc_1 in FIG.
Is applied, the calculation path becomes statements ST11 to ST12.
When it reaches ST14 via ST13 and ST13, it follows the calculation route to ST15 and ST16, respectively. -Effect analysis unit 53 The influence analysis unit 53 obtains a set of variables that are affected by a certain correction. That is, first of all, the one that passes through the modified portion of the given calculation path is detected, and then
For each detected calculation path, the reference definition dependency relationship and the definition reference dependency relationship that occur when executing each are calculated, and finally, all the reference definition dependency relationships and the defined reference dependency relationships and the variables obtained from them are obtained. From the dependencies, find the set of variables that might be affected by the modification.
For example, for the procedure calc_1 in Figure 2, the statement
Consider the case where the value defined for the variable s of ST13 is modified. By using this influence analysis means 53, it is possible to obtain a set of variables that have an influence as shown below.

First, as a calculation route passing through ST13,
"ST11 → ST12 → ST13 → ST14 → ST15" (calculation route 1),
“ST11 → ST12 → ST13 → ST14 → ST16” (calculation route 2) is obtained. Next, the reference definition dependency relationship and the definition reference dependency relationship are obtained. A part of the obtained relationship is shown below. As a relationship that occurs when executing the calculation path 1, the variable q of ST13 is used.
To the variable s of ST13, the variable s of ST15 to the variable u of ST15
There is a reference definition dependency relationship to and a definition reference dependency relationship from the variable s of ST13 to the variable s of ST15. The relationship that occurs when executing the calculation path 2 is from the variable q of ST13 to ST13.
There is a reference definition dependency between the variable s of ST16 and the variable v of ST16, and a definition reference dependency between the variable s of ST13 and the variable s of ST16.

Then, a set of variables that may be affected by the modification is obtained. The dependency relationship between variables can be obtained from the reference definition dependency relationship and the definition reference dependency relationship for both calculation paths. From the obtained dependency between variables, ST
Get the set of variables that depend on the variable s whose value is defined in 13. In the case of procedure calc_1 in Fig. 2, the set of this variable is ST
The variable s referred to in 15, and the variable u defined in ST15,
It consists of a variable s referenced in ST16 and a variable v defined in ST16, and these variables may be affected by the modification to ST13.

Next, a conventional method for realizing the calculation path detecting means 52 and the effect analyzing means 53 which fulfill such functions will be described.

(1) Implementation Example of Calculation Route Detection Means 52 In the calculation route detection means 52, the possibility of being executed by repeatedly applying the following rules R101 and R102 until there is no new calculation route to be traced Find a calculation path. A calculation path from the virtual statement called start to the first statement and a calculation path from the last statement of the calculation path to the virtual statement called end are introduced. -Straight rule (R101) If the statement that the calculation path reaches is not a judgment statement that causes a conditional branch, the calculation path to the next statement is continuously followed. -Branch rule (R102) If the statement that the calculation path reaches is a judgment statement that causes a conditional branch, then both calculation paths corresponding to the branch are followed.

FIG. 3 shows an example of the configuration of such a calculation path detecting means 52. That is, the calculation path detecting means 52 has an input program holding means 52a for holding the input program, a straight-line rule applying means 52b for applying the straight-line rule, a branch rule applying means 52c for applying the branch rule, and already detected. It is composed of the detected calculation route holding means 52d for holding the calculation route and the calculation route analysis control means 52e for controlling the whole.

Here, an example in which each of the above rules is applied to the procedure calc_1 in FIG. 2 is shown. Further, the calculated routes P1011 and P1012 thus obtained are shown in FIG. Note that the number of statements through which the calculation path passes is described according to the example of ST11. Then, the calculation route P1011 is "start → ST11 → (R101) →
ST12 → (R101) → ST13 → (R101) → ST14 → (R102) → ST15 → en
d ”, and the calculation route P1012 is“ start → ST11 → (R101)
→ ST12 → (R101) ST13 → (R101) → ST14 → (R102) → ST16 → en
d ”. Here, (R101) and (R102) indicate which rule is applied. These calculation paths P1011, P1
Considering 012, it can be said that the calculation route starting from start and reaching ST11 can reach ST12 by applying R101, and similarly reach ST13 and ST14.
Even by applying R101, it can be said that the calculation route that starts from start and reaches ST14 via ST11, ST12, and ST13 reaches both ST15 and ST16 by applying R102.

Similarly, an example in which each of the above rules is applied to the procedure calc_2 shown in FIG. 5 is shown below. Procedure ca
lc_2 contains two conditional statements. Obtained calculation path P1
021 to P1024 are shown in FIG. As shown in the figure, the calculation route P1021 is “start → ST21 → (R102) → ST22 → (R101) → ST24.
→ (R101) → ST25 → (R102) → ST26 → (R101) → ST27 → end 」
, The calculation route P1022 is "start → ST21 → (R102)
→ ST22 → (R101) → ST24 → (R101) → ST25 → (R102) → ST28 →
(R101) → ST29 → end ”, and calculation route P1023 is“ start → ST21 → (R102) → ST23 → (R101) → ST24 → (R101)
→ ST25 → (R102) → ST26 → (R101) → ST27 → end ”, and calculation path P1024 is“ start → ST21 → (R102) → ST23 →
(R101) → ST24 → (R101) → ST25 → (R102) → ST28 → (R101) →
ST29 → end ”.

(2) Implementation Example of Impact Analysis Means 53 As shown in FIG. 7, the impact analysis means 53 is configured to execute the following steps S201 to S204.
Then, the influence analysis unit 53 uses these steps S201 to S2.
By sequentially applying 04, the set of variables affected by the variables appearing in a certain correction part is obtained.

Step S201 is a step of detecting a route passing through the correction portion, and is a step of obtaining a route passing through the correction portion of interest from the calculation routes detected by the calculation route detecting means 52. is there.

Step S202 is a step of detecting a reference definition dependency relationship and a definition reference dependency relationship with respect to a certain route, and for the certain calculation route obtained in S201, the following S202
By sequentially applying each substep from -1 to S202-4, the reference definition dependency relationship and the definition reference dependency relationship for the calculation path are obtained.

Sub-step S202-1 is a variable-definition line number detection sub-step, which is executed first. This sub-step S202-1 detects the name of the variable whose value is defined when executing the calculation route and the number of the statement in which the variable appears for the calculation route of interest, and then determines these. To record. That is, every time a variable passed as an argument when a procedure is called or a variable described on the left side in an assignment statement appears, the variable name and statement number are detected.

Sub-step S202-2 is a variable-referenced line number detection sub-step. After execution of sub-step S202-1, a value is referred to when the calculation path is executed for the calculation path of interest. After detecting the name of the variable or constant to be stored and the number of the statement in which the variable or constant appears, these are recorded. That is, the variable returned as an argument when exiting the procedure or the variable (or constant) described on the right side of the assignment statement is detected.

Sub-step S203-3 is a reference definition dependency detection sub-step, which is the variable definition line number detection step S202-1 or the variable reference line number detection sub-step.
The reference definition dependency is detected by using the result of S202-2. Further, sub-step S202-4 is a definition reference dependency detection sub-step, in which the result of the variable definition line number detection step S202-1 and the variable reference line number detection sub-step S202-2 is used. It also detects well-defined reference dependencies.

Step S203 is a step of detecting reference definition dependency relations and definition reference dependency relations with respect to all the routes. Step S202 is applied to all the calculation routes obtained in step S201, and all the calculation routes are calculated. The reference definition dependency and the definition reference dependency are detected.

Step S204 is an influence spread area detecting step, and appears in the modified portion by using the reference definition dependency obtained in steps S202 and S203 and the dependency relationship between variables obtained from the definition reference dependency. It seeks variables that depend on variables. The set of variables obtained here is the set of variables affected by the variables appearing in the correction portion of interest.

(Execution Example by Conventional Method-Part 1) Next, the influence analysis means 5 for the procedure calc_1 shown in FIG.
An example where 3 is applied will be described. Here, the procedure calc_1
When the statement ST13 “s: = q + 2” of is modified to “s: = q + 3”, an example of obtaining a set of variables affected by this modification is shown below. Then, the obtained set of variables is shown in FIG.

First, the step S201 of detecting a route passing through the modified portion is applied. Then, the calculation path detecting means 52
Among the calculation paths P1011 and P1012 detected by (see FIG. 4), the ones passing through the statement ST13 are obtained as P1011 and P1012 as shown in FIG. Subsequently, the reference definition dependency relationship and the definition reference dependency relationship detection step S202 for a certain route are applied, and the reference definition dependency relationship and the definition reference dependency relationship for the calculation route P1011 are obtained.

In the execution of this step S202, first, the line number detection sub-step S202-1 of the variable definition is applied, and the number of the statement whose value is defined for each variable when passing through the calculation path P1011 and its Variable names and are required. The obtained results are shown in Table 1.

[0027]

[Table 1] It is read that, for example, the value of the variable p, q, u, v is defined at the time of start, and the value of the variable u is defined at the statement ST11. In addition, each variable p, q, u, v
Is an argument when calling the procedure calc_1.
lc_1 shall be defined at start.

Subsequently, the variable reference line number detection sub-step S202-2 is applied, and when the calculation path P1011 is executed, the number of the statement in which the value of each variable and each constant is referred to and the variable name thereof are obtained. To be Table 2 shows the obtained results.

[0029]

[Table 2] This table is read, for example, when the value of the variable q is referred to in the statement ST13 and the value of a certain constant is referred to in ST12.

Next, the reference definition dependency detection substep
S202-3 is applied. In this sub-step, the reference definition dependency that occurs when the calculation path P1011 is executed is obtained from the results obtained in the sub-steps S202-1 and S202-2. Here, by referring to the same row in Table 1 and Table 2, the reference definition dependency relationship is obtained. Table 3 shows the relationship obtained.

[0031]

[Table 3] This table shows, for example, certain constants (here,
ST11 reads that there is a reference definition dependency from "0" in "u: = 0" to a variable u whose value is defined in statement ST11, and a variable q whose value is referenced in ST13 Read that there is a reference definition dependency on the variable s whose value is defined in ST13. Here, in the former case, the variable u defined in ST11 depends on a certain constant that refers to a value, and in the latter case, the variable s defined in ST13 becomes the variable q referred to in ST13. It has been shown to be dependent.

Next, the definition reference dependency detection substep
S202-4 is applied, and the definition reference dependency that occurs when the calculation path P1011 is executed is obtained. By paying attention to the same variables in Table 1 and Table 2, the definition reference dependency can be obtained. Table 4 shows the relationships obtained.

[0033]

[Table 4] This table reads, for example, that there is a definition reference dependency from the variable p whose value is defined at start to the variable p whose value is referenced in the statement ST14, and in the variable s to ST15 whose value is defined in ST13. Read that there is a definition reference dependency on the variable s whose value is referenced. Here, in the former case, the variable p referred to in ST14 depends on the variable p defined in start, and in the latter case, the variable s referred to in ST15 is
It is shown that it depends on the variable s defined in ST13. FIG. 10 shows the dependency relationship between variables with respect to the calculation path P1011 obtained as described above.

The reference definition dependency relationship and the definition reference dependency relationship detection step S203 for all the routes are applied so that step S202 including the above-mentioned sub-steps S202-1 to S202-4 is sequentially executed for all the routes. It Here, all calculation paths P1011 and P1012 obtained in step S201 are
In order to obtain the reference definition dependency relationship and the definition reference dependency relationship with respect to and, following the processing for the calculation path P1011 described above,
Apply 202. Table 5 shows the reference definition dependency relationships and Table 6 shows the definition reference dependency relationships for the calculation path P1012.
FIG. 11 shows the dependency relationship between variables for the calculation path P1012.
Shown in.

[0035]

[Table 5]

[0036]

[Table 6] Next, in step S203, the reference definition dependency relationship and the definition reference dependency relationship for both the calculation paths P1011 and P1012 obtained in step S201 are obtained. Computational path P1011 and P10
In order to obtain the reference definition dependency relation with respect to 12, it is sufficient to obtain the union of Table 3 and Table 5. The results are shown in Table 7.
How to read this table is the same as in Table 3.

[0037]

[Table 7] Similarly, in order to obtain the definition reference dependency for both the calculation paths P1011 and P1012, it is sufficient to obtain the union of Tables 4 and 6. The results are shown in Table 8. How to read this table is the same as in Table 4. Also, obtained by the above processing,
The dependency relationships between variables when the calculation paths P1011 and P1012 are executed are shown in FIG.

[0038]

[Table 8] When the execution of step S203 ends, the influence spread area detection step S204 is applied. Here, a set of variables affected by the variables defined in the statement ST13 is obtained based on the reference definition dependency relationship and the definition reference dependency relationship (see Table 7 and Table 8) obtained in step S203.

First, all variables that depend on the variables defined in ST13 are obtained. Next, all variables that depend on the calculated variables are calculated. In this manner, the variables that depend on the determined variables are sequentially obtained, and the dependent variables are continuously obtained until there are no new dependent variables. Table 9 shows the reference definition dependency relationship and the definition reference dependency relationship used in this obtaining process.

[0040]

[Table 9] By using these reference definition dependency relationships and definition reference dependency relationships, a set of affected variables is obtained from the variables defined in ST13, and the results are shown in Table 10. As described above, the result is shown in FIG.

[0041]

[Table 10] As described above, when the statement ST13 in the procedure calc_1 is modified, the set of variables affected by the modification can be obtained.

(Execution Example by Conventional Method—Part 2) Next, an implementation example of obtaining the influence spread area by applying the conventional technique to a program including a plurality of conditional statements in the calculation path will be described. Here, consider the procedure calc_3 in the program shown in FIG. ST32 "s: = u * 2"
When is modified to “s: = u * 4”, using conventional technology,
The variables affected by this modification can be determined as follows.

First, the calculation route detecting means 52 is used to obtain four calculation routes P1031 to P1034 shown in FIG. Then, according to step S201 of the impact analysis means 53, P1031 and P1032 are obtained as calculation routes passing through ST32, and according to steps S202 and S203 of the impact analysis means 53, P1031 and P103
Find reference definition dependency and definition reference dependency on 1032. Table 11 shows the obtained reference definition dependency relationship, and Table 12 shows the obtained definition reference relationship. Also, the dependency relationship between variables when executing the calculation path P1031, the calculation path P10
The dependency relationships between variables when executing 32 are shown in FIG.

[0044]

[Table 11]

[0045]

[Table 12] Then, according to step S204 of the impact analysis means, by using the obtained reference definition dependency relationship and the dependency relationship between the variables obtained by the definition reference dependency relationship, the set of variables dependent on the variable defined in ST32 is detected. . The set obtained here is the set of variables affected by the variables defined in ST32. Table 13 shows a set of detected variables. Also, FIG. 16 shows the dependency relationship of variables that depend on the variables defined in ST32 (it is assumed that P1032 is executed).

[0046]

[Table 13] As shown above, the statement in procedure calc_3
When ST32 is modified, the set of variables affected by the modification can be obtained. The analysis of the variables affected by this conventional method shows, for example, as shown in Table 13.
It has been determined that the variable i defined in ST39 is affected by the variable defined in ST32.

Here, it is investigated whether the calculation path P1032 may actually be executed.

In the calculation path P1032, the control shifts from ST31 to ST32 instead of ST33. Therefore, in ST31, the condition (p> 0) becomes true. Then, in the calculation path P1032, after passing through ST32 and ST34, ST35 is reached. Here, in calculation path P1032, ST31 to ST32 and S
Since there is no assignment statement to the variable p while passing through T34, the value of p in ST35 is the same as the value of p in ST31. Since the condition (p> 0) is true in ST31, ST35
The condition (p> 0) is always true. Therefore, ST31 →
The calculation path executed as ST32 → ST34 → ST35 will never be executed in the direction of ST38.
From the above, it can be seen that P1032 is a calculation path that is not actually executed.

Using the above-mentioned conventional technique, as shown above, a calculation path that is not actually executed (for example, P1032)
Even in this case, the calculation route detecting means 52 may determine that the calculation route may be executed.

Here, taking into account that the calculation path P1032 is not actually executed, the set of variables affected by the modification to ST32 is obtained again. Assuming that the calculation path P1032 is never executed, in step S201 of the influence analysis means 53, it is required that only P1031 is the calculation path passing through ST32. Then, S2 of the impact analysis means 53
By 02 and S203, the reference definition dependency relationship and the definition reference dependency relationship for the calculation path P1031 are shown in Table 14 respectively.
And detected as shown in Table 15. Further, FIG. 17 shows the dependency relationship between variables that occurs when P1031 is executed.

[0051]

[Table 14]

[0052]

[Table 15] Then, in S204 of the influence analysis unit 53, a set of variables depending on the variable defined in ST32 is obtained from the obtained reference definition dependency relationship and the definition reference dependency relationship. The set of variables is affected by the variable of interest. Table 16 shows the obtained set of variables. Also, the calculation path P1032
FIG. 18 shows the dependency relationships of variables that depend on the variables defined in ST32 when is not executed.

[0053]

[Table 16] If the conventional technique is used, it is treated as passing through the calculation path P1032. Therefore, for example, it was determined that the variable i defined in ST39 is influenced by the variable defined in ST32. However, in reality, the variable defined in ST32 does not influence the variable i defined in ST39, since it never passes through the calculation path P1032. As described above, the conventional technique has a problem that it is determined that the influence is exerted even though the influence is not actually exerted.

[0054]

As described above, when the conventional technique is applied, it may be judged that the influence is exerted although the influence by the program modification is not actually exerted. Occurs. The root cause of this problem is to detect computational paths that are not actually executed. For example, in a program,
The calculation path goes through two conditional statements that cause a branch of the calculation path, the first branch is in the then direction, and the second branch is el.
The expressions of the judgment part for the two conditional sentences that follow the se direction are the same. The values of all variables appearing in the expression of the judgment part in the conditional sentence are always the same in the two conditional sentences,
And if all the functions included in the formula satisfy the three conditions that output the same value if the input value is the same at the same time, the calculation path is not actually executed. According to this, it will be detected as a calculation path to be executed. As a result, a dependency relationship between variables that exists only when tracing a calculation path that is not actually executed, that is, a dependency relationship between variables that should not exist in actual program execution is detected. As a result, a variable that will be affected based on a dependency that does not actually exist will be generated, and it will be judged that it will be affected even if the modification does not actually affect it. It will be.

The object of the present invention is to solve the above-mentioned problems,
An object of the present invention is to provide an influence analysis device by modifying a program that does not actually determine the influence but determines that the influence is not generated.

[0056]

According to a program modification influence analysis apparatus of the present invention, a program consisting of a group of statements to be executed sequentially is analyzed, and variables affected by the program modification are analyzed. In the influence analysis device, the execution order of the programs is traced according to the syntax information of the program, and a calculation path detecting unit that obtains a sequence of the statements obtained by following the execution order as a calculation path, and a conditional statement that causes a branch. Save the constraint condition for the variable that determines the truth or falseness of the logical expression in the conditional statement when passing, and monitor the value of the variable for the section up to the conditional statement that appears later in the calculation path. Verify the constraint condition of the conditional statement that appears after that, and if the constraint condition can be uniquely determined, appear after that One of the branches of the conditional statement that is executed is determined along the calculation path in order to determine that it is not executed, and a calculation path limiting unit that finds a calculation path that is not executed; and a calculation path limiting unit that is not executed among the calculation paths Among the calculation paths not found as the ones, the ones passing through the modified portion are detected, and the dependency relationship between the variables is obtained from the relationship between the definition of the variable and the reference for each of the detected calculation paths. , An effect analysis unit for obtaining a set of variables that are likely to be affected by the modification.

[0057]

In the influence analysis apparatus by modifying the program of the present invention, since the calculation route limiting means for finding the calculation route which is not executed is provided, it is not actually executed when the dependence relation between variables is obtained by the influence analysis means. Since the calculation route can be excluded in advance, it is possible to prevent the determination that an influence is not exerted even if the influence is not exerted.

Now, the execution of the impact analysis using the apparatus of the present invention will be described.

First, the calculation route detecting means detects a calculation route which may be executed. Then, the calculation route limiting means determines, for each calculation route detected by the calculation route detecting means, one that is not actually executed. Next, the influence analysis unit removes the calculation route detected by the calculation route limiting unit from the calculation route detected by the calculation route detection unit. Then, it is determined whether or not the influence is exerted on the basis of the calculation paths remaining without being removed. By performing the influence analysis in this manner, it is possible to correctly determine (if there is no influence) a portion that has not been actually influenced in the area that has been conventionally determined to have an influence.

Next, regarding the procedure of detecting a calculation route that is not executed by the calculation route limiting means, the procedure calc of FIG.
_3 ST31 → ST32 → ST34 → ST35 → ST38 → ST39 calculation path P1
An example will be described as to whether or not 032 (see FIG. 14) is actually executed.

Generally, when a certain calculation path passes through a conditional statement that causes a branch, only one calculation path corresponding to the branch is actually executed, so that the truth of the logical expression in the conditional statement is determined. In the case of calculation route P1032, the calculation route is from ST31 to t
Because it goes to ST32 in the hen direction, the judgment sentence of ST31 (p> 0)
Will be true. By determining the truth of the logical expression in this way, the constraint condition of the variable in the passing conditional statement can be obtained. This constraint condition is (p>
0) is true, the variable constraint condition (p> 0) in ST31 is satisfied.

As the calculation path is continuously executed, the expression form of the constraint condition of the obtained variable is sequentially updated. In the case of the calculation path P1032, the variable constraint condition (p> 0) is unchanged during the passage from ST31 to ST32 and ST34 because there is no substitution to the variable p. At this time, the calculation route is 1
When one conditional statement is executed and then another conditional statement is executed, the constraint relationship of the variable that should be satisfied in the reached conditional statement is updated by sequentially updating the constraint relationship of the variables found in the calculation path that has passed. It becomes possible to obtain the conditions. In the case of calculation path P1032, one conditional statement ST31 and ST32
It is assumed that another conditional statement ST35 has been executed via the and ST34. The constraint condition that the variable should satisfy in the reached conditional sentence ST35 is (p> 0).

By applying the constraint condition of the variable obtained in this way to the reached conditional sentence, it may be said that the logical expression in the conditional sentence is either true or false. . In the case of calculation path P1032, the constraint condition that the variable should satisfy in ST35 is (p> 0), so it can be said that the determination part of the conditional statement in ST35 is always true. Here, if it can be said that the logical expression is either true or false, it means that one of the two calculation paths corresponding to the branch is not executed. For calculation path P1032, S
The calculation route executed from T31 → ST32 → ST34 → ST35 is ST35
Since it is not executed in the else direction of, it can be determined that the calculation route is not actually executed in the direction of ST38 from ST35.

In this way, a calculation path that is not actually executed can be detected.

[0065]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 19 is a block diagram showing the configuration of the influence analysis apparatus according to the embodiment of the present invention. This impact analyzer 1
0 is connected to the analysis target program holding device 11 that stores the analysis target program, and the calculation route detection means 12 that detects the execution order of the programs and the calculation route that finds the calculation route that is not actually executed Limiting means 1
5, and an impact analysis unit 13 that analyzes the impact of the modification,
The control means 14 controls the entire operation. Hereinafter, each component will be described.

The calculation path detecting means 12 obtains a calculation path by tracing a series of statements corresponding to each branch each time a conditional statement appears in the calculation path.

Further, the influence analysis means 13 first detects one of the given calculation paths that goes through the applied correction portion, and then, for each detected calculation path, a reference generated when executing each of them. The definition dependency and the definition reference dependency are obtained, and finally, the relations between all the obtained reference definition dependency and the definition reference dependency and the variables obtained from them are used to identify the variables that may be affected by the modification. It seeks a set. The influence analysis unit 13 does not perform the above process on the calculation route which is determined by the calculation route limiting unit 15 described later to be a calculation route that is not actually executed.

Here, the calculation route limiting means 15 is inputted with the calculation route detected by the calculation route detecting means 12 and the program for detecting the calculation route and is not actually executed for each input calculation route? , Outputs after determining whether there is a possibility of execution. FIG. 20 is a block diagram showing a configuration example of the calculation route limiting means 15. As shown in this figure, a program holding unit 21 that holds a program to be analyzed, a calculation route information holding unit 22 that stores data of a calculation route detected by the calculation route detection unit 12, and a calculation route statement ( (Statement) detects a conditional statement such as an if statement and reads the judgment section 23, a conditional judgment statement detection section 23, a constraint condition detection section 24 that detects a restriction condition for the read variable, a judgment section for the detected conditional statement. Condition judgment sentence that records the detected constraint condition
The constraint condition recording unit 25, the constraint condition updating unit 26 that sequentially updates the expression form of the constraint condition each time the constraint condition of the read variable changes, and the constraint condition of the read variable is applied to the detected condition statement and this condition is applied. The calculation path is actually executed based on the judgment result of the logical expression true / false judgment means 27 and the logical expression true / false judgment means 27 for judging whether the logical expression of the sentence is true or false. Calculation route limitation determining means 28 for determining whether there is a possibility that
˜28 and the calculation path limiting control means 29 for controlling the exchange of data between these means 21 to 28.

Next, the operation of the calculation path limiting means 15 will be described with reference to the flowchart of FIG. First, regarding the program held in the program holding means 21 in advance, it is assumed that each calculation route input to the calculation route information holding means 22 is examined (step S301), and attention is paid to one of the calculation routes that has not yet been determined. (Step S302). Here, it is checked whether or not there is a calculation route of interest (step S303). If not, the process proceeds to step S318, and if there is a calculation route of interest, the calculation performed by the condition determination statement detection unit 23 The path is traced from the top and the conditional statements that cause a branch are detected sequentially (step
S304). Then, it is checked whether or not one conditional sentence has been detected, and if not found, the process proceeds to step S315. When the conditional part is detected, the expression of the determination part in the conditional statement is recorded (step S306).

Next, for the detected conditional sentences, the formulas of the judgment section recorded are read out for all the conditional sentences that have passed when the conditional route from the head to the conditional sentence was traced (step S307). Next, for the detected conditional sentence, when the focused calculation path is traced from the beginning to the conditional sentence, it is examined how the constraint condition of the read variable changes, and the constraint condition is changed every time the constraint condition changes. Update means 2
6, the expression form of the constraint condition is sequentially updated. Then, the constraint condition of the variable in the detected conditional sentence is obtained (step S308). The obtained constraint condition of the variable is applied to the detected conditional sentence to determine whether it can be said that the logical expression is true or false (step S309).

As a result of the judgment (step S310) If it cannot be definitely determined whether it is true or false, the following operation is continued.
The process moves to step S317 to search for the next conditional statement. In the case of a definite decision, the calculation route limitation determining means 28 determines whether the logical formula is true or false and which calculation route the focused calculation route branches to in the conditional formula. It is determined whether the route can be continued (step S311). According to this determination (step S312), if traceable, the process proceeds to step S317, and if traceable, it is determined that the focused calculation path is not executed (step S31).
3) Focusing on the next calculation path (step S314), the process proceeds to step S303.

If the conditional expression is not found in step S305, it is determined that the arrived calculation route may be executed (step S315), and the next calculation route is focused on (step S316). Move to S303.

If it is determined in step S310 that the authenticity is not definitely determined, or if it is determined in step S312 that the calculation route has continued, the above process is continued for this calculation route. In order to repeat, the calculation path of interest is continuously followed, the next conditional statement is detected (step S317), and then the process proceeds to step S305.

When there are no more calculation routes to be noted in step S303, the determination result for each calculation route is output (step S318), and the process in the calculation route limiting means 15 is ended. In this way, the calculation route limiting means 15 detects a calculation route that is not actually executed.

Next, the result of carrying out this embodiment for a specific program will be described. Examples 1 to 5 below
Is an example in which the area affected by the program modification can be narrowed down, and the sixth embodiment limits the authenticity of the determination part of the third conditional statement by passing through two conditional statements in a program having three conditional statements. Example 7 is an example of determining whether or not a plurality of independent modifications to a program affect each other.

(Embodiment 1) This is an example of the case where the decision section is the same in a program having two conditional statements, and the variables appearing in the decision section are the same in the two conditional statements. Here, FIG.
Take the procedure calc_3 of the program shown in 3 as an example.

When the calculation route detecting means 12 is used, as shown in FIG. 14, the four calculation routes P1031 to P1034 are detected. Here, the calculation route limiting means 15 determines, for each of the calculation routes P1031 to P1034 detected by the calculation route detecting means 12,
Determine if it may actually be executed.

For example, the calculation route P1031 is determined as follows.

Since the process proceeds from ST31 to ST32, it can be said that (p> 0) is true in ST31. This allows ST
The condition that the variable in 31 must satisfy, that is, the constraint condition of the variable is (p> 0). ST31 to ST via ST32 and ST34
Since the variable p is not substituted while reaching 35, when P1031 reaches ST35, the constraint condition of the variable is (p> 0). When this constraint condition (p> 0) is applied to the judgment section (p> 0) of the conditional sentence of ST35, the judgment section (p> 0) of ST35 is always true. With this, from ST31
It can be said that the calculation route to reach ST35 via ST32 and ST34 continues to follow the then direction to ST35, that is, ST36. As described above, it can be determined that P1031 may be executed.

The calculation path P1032 is determined as follows.

From the example of P1031 shown above, ST31 to ST32
It can be said that the conditional statement determination unit (p> 0) in ST35 is always true when the program reaches ST35 via ST34 and ST34. As a result, it can be said that the calculation route from ST31 to ST35 via ST32 and ST34 does not continue in the else direction to ST35, that is, ST38. As described above, it can be determined that P1032 is not executed.

Similarly, it can be determined that P1033 is not executed and that P1034 may be executed. As described above, conventionally, it was determined that all the calculation paths of P1031 to P1034 may be executed,
In this embodiment, it can be determined that the calculation paths P1032 and P1033 are not executed.

By using the determination result of the calculation path limiting means 15, it is possible to detect the variable which has not been actually influenced, out of the variables which have been conventionally determined to have an influence (see FIG. 18). . Here, ST32 of the procedure calc_3 "s:
As an example, when “= u * 2” is modified to “s: = u * 4”, the variable affected by the modification is detected.

According to the conventional method, the calculation paths passing through ST32 are determined to be P1031 and P1032. Therefore, when the influence analysis means is applied, the reference definition dependency shown in Table 7 and the definition reference relation shown in Table 8 are obtained. Is obtained. Therefore, the definition reference dependency relationship from the variable s defined in ST32 to the variable s referenced in ST34, the reference definition dependency relationship from the variable s referenced in ST34 to the variable t defined in ST34, and ST34 By combining the definition reference dependency from the defined variable t to the variable t referenced in ST39 and the reference definition dependency from the variable t referenced in ST39 to the variable i defined in ST39, ST32 It was determined that the variable s defined in step 39 affects the variable i defined in ST39.

On the other hand, in this embodiment, since it is determined that the calculation route P1032 does not occur, the calculation route passing through ST32 is
It can be said that there is only P1031. Therefore, when the influence analysis unit 13 is applied under the condition that only P1031 exists as the calculation route passing through ST32, the reference definition dependency shown in Table 14 and the definition reference dependency shown in Table 15 are obtained. Further, when variables affected by the variables defined in ST32 are obtained, it can be said that the variables i defined in ST39 are not affected, as shown in Table 16.

From the above, it has been shown that it may be possible to determine that variables do not actually have an effect, out of variables that have been conventionally determined to have an effect, and the areas that have the effect of program modification have been narrowed down.

(Embodiment 2) In a program having two conditional statements, the shape of the judging section is the same except for the variable name,
This is an example when the values of corresponding variables are the same between the two conditional statements. Here, the procedure calc_4 of the program shown in FIG. 22 is taken as an example.

When the calculation route detecting means 12 is used, FIG.
As shown in (4), four calculation paths P1041 to P1044 are detected. Here, the calculation path limiting unit 15 determines whether or not there is a possibility that the calculation paths P1041 to P1044 detected by the calculation path detection unit 12 are actually executed.

The details are the same as in the first embodiment described above, but 2
In the second conditional statement, the method for applying the constraint condition that the variable should satisfy is different.

Similar to the first embodiment, for example, ST41 to ST42
When reaching ST45 via ST44 (calculation route P104
Consider 2). The constraint condition (p> 0) to be satisfied in ST41 is S
Although it is satisfied even at T45, it is impossible to determine whether or not the truth of the conditional statement determination unit (q> 0) in ST45 is determined only by the constraint condition (p> 0). But calca_4
Is called from the program Main4, calc_4
Since it can be said that the constraint condition (p = q) between the variable p and the variable q is satisfied when the calculation path reaches ST41 of
The constraint condition to be satisfied in ST41 is not only (p> 0) but (q
> 0). Also, from ST41 to ST42 and ST
Since there is no substitution to q while reaching ST45 via 44 and 44, it can be said that the constraint condition to be satisfied in ST45 is not only (p> 0) but also (q> 0). Therefore, if this condition (q> 0) is applied to the conditional statement determination section (q> 0) of ST45, the determination section of ST45 is always true. by this,
It can be said that the calculation route from ST41 to ST45 via ST42 and ST44 is not continuously executed in the else direction to ST45, that is, to ST48. As shown above, it can be determined that the calculation path P1042 is not executed.

Similarly, since it is determined that the calculation path P1043 is not executed, it can be determined that P1041 and P1044 may be executed and that P1042 and P1043 may not be executed.

By using this determination result, it is possible to detect a variable that has not been actually affected, among variables that have been conventionally determined to have an effect.

Here, “s: = u * 2” of ST42 of procedure calc_4
When is modified to “s: = u * 4”, consider the case where the variables affected by the modification are detected. The determination method is the same as that of the first embodiment, and in conclusion, conventionally, since it was determined that the calculation route passing through ST42 was P1041 and P1042, the effect of the modification to ST42 is defined in ST49. It was determined that the variable i was reached. However, in this embodiment, P104
Since it is determined that 2 is not executed, it can be determined that the effect of the modification in ST42 does not reach i defined in ST49. From the above, it was shown that among the variables that were previously determined to have an effect, it may be possible to determine that they do not actually have an effect, and the areas affected by the program modification were narrowed down.

(Third Embodiment) In a program having two conditional statements, the judgment statements have different shapes, but there is a relation between variables appearing in the respective judgment sections. Here, the procedure calc_5 in the program of FIG. 24 is taken as an example.

The calculation path detecting means 12 detects four calculation paths P1051 to P1054 as shown in FIG.
Here, the calculation route limiting means 15 is used by the calculation route detecting means 12
For each of the calculation paths P1051 to P1054 detected by, it is determined whether or not there is a possibility that it will actually be executed.

The details are similar to those of the first and second embodiments, but the method for applying the constraint condition that the variable should satisfy in the second conditional statement is different. Similar to the first embodiment, let us consider a case where the vehicle arrives at ST56 from ST51 via ST52, ST54, and ST55 (calculation route P1051). The constraint condition (p> 0) that should be satisfied in ST51 is also satisfied in ST56, but it is determined whether or not the determination unit (q> = 0) of the conditional statement in ST56 determines whether the constraint condition (p> 0) is true. Is impossible. However, in ST54 through which the above-mentioned calculation path passes, the value of the variable q is determined based on the value of the variable p. ST54
Although the constraint condition (p> 0) that the calculation path has reached is satisfied, but in the state where the substitution to q is completed in ST54,
A constraint condition (q <0) is newly generated. The constraint condition (q <0) newly generated in ST54 is still satisfied in ST56 because there is no substitution for q on the route reaching ST56. Therefore, if this constraint condition (q <0) is applied in the conditional statement determination section (q> = 0) of ST56, the determination section of ST56 is always false. By this ST
It can be said that the calculation route from 51 to ST56 via ST52, ST54, and ST55 is not continuously executed in the then direction to ST56, that is, to ST57. As shown above, P1
It can be determined that 051 is not executed.

It can be seen that the calculation path P1054 is not executed by the same procedure, and eventually it is possible to determine that P1052 and P1053 may be executed and that P1051 and P1054 are not executed.

By using this determination result, it is possible to detect a variable that has not been actually affected, among variables that have been conventionally determined to have an effect. Where the procedure
When “s: = u * 2” in ST52 of calc_5 is modified to “s: = u * 4”, let us consider an example of detecting variables affected by the modification. The determination method is the same as in the first embodiment.

That is, conventionally, it was determined that the calculation route passing through ST52 was P1051 and P1052, and therefore it was determined that the effect of the correction on ST52 extends to the variable h defined in ST57. However, in the present embodiment, since it is determined that P1051 is not executed, it can be determined that the effect of the modification on ST52 does not reach the h defined in ST57. From the above, it was shown that among the variables that were previously determined to have an effect, it may be possible to determine that they do not actually have an effect, and the areas affected by the program modification were narrowed down.

(Embodiment 4) This is an example of a case in which in a program having two conditional statements, a new condition is added to the determination section of the conditional statement that appears later, in the determination section of the conditional statement that appears first. Here, the procedure calc_6 in the program shown in FIG. 26 is taken as an example.

When the calculation route detecting means 12 is used, FIG.
As shown in, the four calculation paths P1061 to P1064 are detected. The calculation path limiting means 15 determines whether or not there is a possibility that the calculation paths P1061 to P1064 detected by the calculation path detecting means 12 will actually be executed. The details are the same as in Example 1 and the like, but in the second conditional statement, the method for applying the constraint condition that the variable should satisfy is different.

Similar to the first embodiment, for example, ST61 to ST63
When reaching ST65 via ST64 (calculation path P106
Think 3). Restraint conditions to be satisfied in ST61 (p <= 0)
Is also met at ST65. Therefore, the determination section [(p> 0) and (q> 0)] of the conditional statement of ST65 is always false. Therefore, it can be said that the calculation route from ST61 to ST65 via ST63 and ST64 is not continuously executed in the then direction to ST65, that is, to ST66. As shown above,
It can be determined that P1063 is not executed.

After all, it can be determined that P1061, P1062, and P1064 may be executed, and that P1063 may not be executed.

By using this determination result, it is possible to detect a variable that has not been actually affected, out of the variables that were conventionally determined to have an effect. Where calc_6
When “s: = u * 3” in ST63 is modified to “s: = u * 5”, let us consider an example of detecting variables affected by the modification. The determination method is the same as in the first embodiment.

That is, in the past, it was determined that the calculation paths passing through ST63 were P1063 and P1064. Therefore, it was determined that the effect of the correction on ST63 extends to the variable h defined in ST66. However, in this embodiment, since it is determined that P1063 is not executed, it can be determined that the effect of the modification in ST63 does not reach the h defined in ST66.

From the above, it has been shown that it may be possible to determine that the variables do not actually affect, among the variables that have conventionally been determined to affect, and that the areas affected by the program modification have been narrowed down.

(Embodiment 5) This is an example of the case where variables appearing in each judgment sentence are related to each other in a program having two conditional sentences. Here, the procedure calc_7 in the program shown in FIG. 28 is taken as an example.

When the calculation route detecting means 12 is used, FIG.
As shown in, the four calculation paths P1071 to P1074 are detected. The calculation path limiting unit 15 determines whether or not there is a possibility that the calculation paths P1071 to P1074 detected by the calculation path detection unit 12 are actually executed. The details are the same as in Example 1 and the like, but in the second conditional statement, the method for applying the constraint condition that the variable should satisfy is different.

Similar to the first embodiment, for example, ST71 to ST72
When reaching ST76 via ST74 and ST75 (calculation route
Consider P1072). Constraints that ST71 must meet (p>
0) is also satisfied in ST76, but this constraint (p> 0)
Only by itself, it is impossible to judge whether the truth of the conditional statement judgment section (q> 0) in ST76 is determined. However, in ST74 through which the above-described calculation path P1072 passes, the value of the variable q is determined based on the value of the variable p. When the calculation route reaches ST74, the constraint condition (p> 0) is satisfied, but ST
In the state where the substitution to q is completed in 74, a constraint condition (q> 10) is newly generated. The constraint condition (q> 10) newly generated in ST74 is still satisfied in ST76 because there is no substitution for q on the route reaching ST76. Therefore, if this constraint condition (q> 10) is applied in the conditional statement determination unit (q> 0) of ST76, the determination unit of ST76 is always true. Therefore, it can be said that the calculation route from ST71 to ST76 via ST72, ST74, and ST75 is not continuously executed in the else direction to ST76, that is, to ST79. As shown above, P1072
Can be determined not to be executed.

In the end, it can be determined that P1071, P1073, and P1074 may be executed, and that P1072 is not executed.

By using this determination result, it is possible to detect a variable that has not been actually affected, among variables that were conventionally determined to have an effect. Where the procedure
When “s: = u * 2” in ST72 of calc_7 is modified to “s: = u * 4”, let us consider an example of detecting variables affected by the modification. The determination method is the same as in the first embodiment.

In other words, conventionally, it was determined that the calculation route passing through ST72 was P1071 and P1072, so it was determined that the effect of the correction on ST72 would extend to the variable i defined in ST80. However, in this embodiment, since it is determined that P1072 is not executed, it can be determined that the effect of this modification does not reach i defined in ST80. From the above, it was shown that among the variables that were previously determined to have an effect, it may be possible to determine that they do not actually have an effect, and the areas affected by the program modification were narrowed down.

(Embodiment 6) This is an example in which the authenticity of the determination section for the third conditional statement can be limited by passing through the two conditional statements in a program having three conditional statements. Here, the procedure calc in the program of FIG.
Take _8 as an example.

When the calculation route detecting means 12 is used, FIG.
As shown in (8), eight calculation paths P1081 to P1088 are detected. The calculation path limiting unit 15 determines whether or not there is a possibility that the calculation paths P1081 to P1088 detected by the calculation path detection unit 12 are actually executed. For example, the calculation path P1082 is determined as follows.

It can be said that (p> 0) is true in ST81 in order to proceed from ST81 to ST82. This makes ST81
The constraint condition that the variable in (4) should satisfy is (p> 0). ST
Since substitution is not performed for p from 81 to ST84 via ST82, when P1082 reaches ST84, the constraint condition to be satisfied by the variable is (p> 0). This constraint condition (p> 0) in the judgment section (q> 0) of the conditional sentence of ST84
Even if is applied, it is not possible to determine the authenticity of the determination unit (q> 0) in ST84. However, the calculation route is from ST81 to ST82
After reaching 84, the calculation route P1082 progresses from ST84 to ST85. Therefore, in ST84, the constraint condition determined in ST81 (p>
Besides 0), a new constraint condition (q> 0) can be obtained. For the calculation route reaching ST87 via ST81, ST82, ST84 and ST85, while passing ST84 to ST85,
Since neither the variable p nor the variable q is substituted, the constraint condition [(p> 0) and (q>
0)] also holds in ST87. Therefore, if this constraint condition [(p> 0) and (q> 0)] is applied to the determination part [(p> 0) and (q> 0)] of the conditional statement of ST87, the determination statement of ST87 becomes Always true. This makes ST81
It can be said that the calculation path from ST to ST87 via ST82, ST84, and ST85 continues to be executed, and the else direction to ST87, that is, ST89 is not continuously executed. As described above, it can be determined that P1082 is not executed.

Similarly, P1081, P1084, P1086 and P1088
May be executed, and P1083, P1085 and P1
It can be determined that 087 and 087 are not executed. After all, according to the conventional method, P1081, P1082, P1083, P1084, P1085 and P
Although it was determined that 1086, P1087, and P1088 may be executed, according to the present embodiment, P1082, P1083, and P1085
And P1087 could not be executed.

(Embodiment 7) This is an example in which it is possible to show that the areas affected by a plurality of independently applied modifications are different. Here, the procedure device_driver and the procedure device_io in the program of FIG. 32 are taken as an example.
These procedures device_driver and device_io are for directly operating the external input / output port from the console to input / output data, and the procedures Port_in and Port_out called in the procedure device_io are procedures for directly executing input / output respectively. Is.

Here, for example, in the procedure advice_io,
Modification 1 in which ST111 is changed only from "d: = data" to "d: = data * 4", and ST114 is changed to "data: =" in procedure device_io.
Consider a case in which after performing independently the modification 2 that only changes from "d" to "data: = d * 2", both modified parts are reflected in the same program.

When the calculation route detecting means 12 is used, FIG.
As shown in FIG. 8, eight calculation paths P1101 to P1108 were detected as executable calculation paths. Based on this, by using the impact analysis method as in the conventional method, the impact of the modification 2 is tempdata referenced in ST106.
And io_data1 defined in ST107, tempdata defined in ST108, and dat referenced in ST111.
It has been determined to extend to a and d defined in ST111. Therefore, it is determined that the variable defined in ST111 out of the set of variables affected by the modification 2 is modified by the modification 1 performed independently of the modification 2.

However, when the calculation route limiting means 15 in this embodiment is used, the calculation routes P1102, P1103, P1104 and P11 are calculated.
It can be determined that 05, P1106, and P1107 are not executed.
From this judgment, it can be determined that the effect of modification 2 does not reach the variables defined in ST111, and the set of variables affected by modification 2 and the set of variables affected by modification 1 do not intersect, and both modifications affect each other. It can be determined that they do not affect each other.

[0121]

As described above, according to the present invention, by providing the calculation route limiting means for finding the calculation route that is not executed by saving the constraint condition for the variable and verifying the constraint condition in the next conditional statement, When calculating the dependency between two, it is possible to exclude in advance the calculation paths that are not actually executed, so when determining what the impact of the program modification will be, it will affect even those that do not really affect. There is an effect that it is possible to prevent the judgment that it extends.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a conventional effect analysis device by modifying a program.

FIG. 2 is a diagram illustrating an example of a program including a calculation path that passes one conditional statement.

FIG. 3 is a block diagram showing a configuration of a calculation route detecting means.

4 is a diagram showing a calculation route obtained by a calculation route detecting means for a procedure calc_1 in the program shown in FIG.

FIG. 5 is a diagram showing an example of a program including a calculation path passing through two conditional statements.

6 is a diagram showing a calculation route obtained by a calculation route detecting means for a procedure calc_2 in the program shown in FIG.

FIG. 7 is a block diagram showing a configuration of an influence analysis unit.

FIG. 8 is a diagram showing variables that depend on variables defined in ST13 in procedure calc_1.

FIG. 9 is a diagram showing a calculation route via ST13 in procedure calc_1.

FIG. 10 is a diagram showing a dependency relationship between variables that occurs when the calculation path P1011 is executed.

FIG. 11 is a diagram showing a dependency relationship between variables that occurs when the calculation path P1012 is executed.

FIG. 12 is a diagram showing a dependency relationship between variables that occurs when the calculation paths P1011 and P1012 are executed.

FIG. 13 is a diagram showing an example of a program including a calculation path passing through two conditional statements.

14 is a procedure calc_3 in the program shown in FIG.
It is a figure which shows the calculation route which the calculation route detection means calculated | required with respect to.

FIG. 15: Execution of calculation path P1031 and calculation path P1032
It is a figure which shows the dependency relationship between the variables which arises at the time of executing.

FIG. 16 is a diagram showing variables depending on the variables defined in ST32, assuming that the calculation path P1032 is executed.

FIG. 17 is a diagram showing a dependency relationship between variables that occurs when the calculation path P1031 is executed.

FIG. 18: If the calculation path P1032 is not executed, ST32
It is a figure which shows the variable which depends on the variable defined by.

FIG. 19 is a block diagram showing a configuration of an influence analysis device according to an exemplary embodiment of the present invention.

FIG. 20 is a block diagram showing a configuration of a calculation route limiting unit.

FIG. 21 is a flowchart showing the operation of the calculation route limiting means.

FIG. 22 is a diagram showing an example of a program including a calculation path passing through two conditional statements.

23 is a procedure calc_4 in the program shown in FIG.
It is a figure which shows the calculation route which the calculation route detection means calculated | required with respect to.

FIG. 24 is a diagram showing an example of a program including a calculation path passing through two conditional statements.

FIG. 25 is a procedure calc_5 in the program shown in FIG.
It is a figure which shows the calculation route which the calculation route detection means calculated | required with respect to.

FIG. 26 is a diagram showing an example of a program including a calculation path passing through two conditional statements.

FIG. 27 is a procedure calc_6 in the program shown in FIG.
It is a figure which shows the calculation route which the calculation route detection means calculated | required with respect to.

FIG. 28 is a diagram showing an example of a program including a calculation path passing through two conditional statements.

FIG. 29 is a procedure calc_7 in the program shown in FIG.
It is a figure which shows the calculation route which the calculation route detection means calculated | required with respect to.

FIG. 30 is a diagram showing an example of a program including a calculation path passing through three conditional statements.

FIG. 31 is a procedure calc_8 in the program shown in FIG.
It is a figure which shows the calculation route which the calculation route detection means calculated | required with respect to.

FIG. 32 is a diagram showing an example of a program for directly operating an input / output port from a console.

33 is a procedure device in the program shown in FIG. 32.
It is a figure which shows the calculation route which the calculation route detection means calculated with respect to _driver.

[Explanation of symbols]

 10,50 Impact analysis device 11,51 Analysis target program holding device 12,52 Calculation path detection means 13,53 Impact analysis means 14,54 Control means 15 Calculation path limiting means 21 Program holding means 22 Calculation path information holding means 23 Condition determination Sentence detecting means 24 Restraint condition detecting means 25 Condition judgment sentence / restraint condition recording means 26 Restraint condition updating means 27 Logical expression true / false judgment means 28 Calculation route limitation determining means 29 Calculation route limiting control means

Claims (1)

[Claims] 1. A program modification influence analysis apparatus for analyzing a variable affected by the modification of a program for a program consisting of a group of statements to be sequentially executed, wherein the program execution is performed according to syntax information of the program. Computation path detecting means for finding a sequence of the sentence obtained by tracing the execution order and the sentence sequence obtained as a result of the execution order, and determining whether the logical expression in the conditional statement when branching through the conditional statement is true or false The constraint condition for the variable is saved, and whether or not the value of the variable is changed is monitored in the section up to the conditional sentence that appears later in the calculation path, and the constraint condition of the conditional sentence that appears later is verified, If the condition can be uniquely determined, it is judged that one of the branches of the conditional statement that appears after that is not executed. The correction is performed from the calculation route limiting means that finds a calculation route that is not executed by following the calculation route and the calculation route that is not found to be not executed by the calculation route limiting device among the calculation routes. An impact analysis that detects the one passing through a part, obtains the dependency between variables from the relation between the definition of the variable and the reference for each of the detected calculation paths, and obtains the set of variables that may be affected by the modification. An effect analysis device by modifying a program, which comprises: