JP5170555B2 - Error trace simplification system, error trace simplification method, and program - Google Patents

Description

  The present invention relates to an error trace simplification system, and more particularly to an error trace simplification system in source code verification.

  Conventionally, there is a source code verification method that can verify a source code of a computer program and present an error trace, that is, a path where an error occurs to a user.

  Error tracing is performed at each step (program step) executed until an error occurs, the line number on the source code corresponding to the step, the substitution expression executed at that step, and evaluated at that step. And the value of the variable in that step.

  When the user refers to such an error trace, the cause of the error can be investigated.

  This can be said to be a great advantage when compared to a source code verification method that does not present an error trace. As a source code verification method that does not present an error trace, for example, there is Spint (see Non-Patent Document 1).

  Note that the source code verification method for presenting an error trace generally has the following characteristics in order to require strict calculation. For example, in the source code verification method that presents an error trace, an expression that statically determines an address (static access) can be handled at a location that accesses a memory area in the source code, but an expression that dynamically determines an address ( Dynamic access) cannot be handled.

  General source code includes many dynamic accesses, such as when an array index is a variable or when a pointer operation is performed using a variable. Since the source code verification method as described above cannot use dynamic access, the source code cannot be handled as it is.

  In such a case, a method of rewriting dynamic access to static access can be used. As means for this, a technique using conditional branching is known (see Non-Patent Document 2).

  A technique is known in which dynamic access is rewritten to static access using a conditional branch by a conditional operator, and then a source code verification method is applied (Non-patent Document 3). reference). Such rewriting is called flattening.

  As described above, source code verification can be applied to source code including dynamic access.

  However, the conventional source code verification method has a problem that the user has a great effort to refer to the error trace.

  This is because the error trace that is the output of the source code verification technique is based on the flattened source code. Since the source code after flattening includes many operations using conditional operators, as a result, the error trace also becomes complicated including many operations using conditional operators. It can be said that interpreting a complex expression using an operation by a conditional operator is a labor-intensive work for the user.

  As a related technique, Japanese Laid-Open Patent Publication No. 2000-215037 (Patent Document 1) discloses a source code display device, a source code display method, and a debug processing device. In this related technology, if there is a branch process during step execution of a program, the branch process condition is analyzed, the line that is not executed under that condition and the line that is executed are examined, and the color of the line that is not executed in the source code display stands out. It is lost.

  Japanese Patent Laid-Open No. 2001-142716 (Patent Document 2) discloses an in-loop conditional branch deletion optimization method. In this related technology, the code that became unnecessary due to the change from the conditional branch code to the unconditional branch code (the unconditional branch code and the code that has never been executed due to the change) is deleted. .

JP 2000-215037 A JP 2001-142716 A IEEE SOFTWARE January / February 2002 Improving Security Usable Extensible Lightweight Static Analysis <http: // www. cs. virginia. edu / papers / ieessoftware. pdf> "Resolution, Optimization, and Encoding of Pointer Variables for the Behavioral Synthesis from C, IEEE TRANSACTIONS ON COMPUTER-AIDED DESIGN OF INTEGRATED CIRCUITS AND SYSTEMS, VOL.20, NO.2, FEBRUARY 2001" <http: // citeseerx. ist. psu. edu / viewdoc / download? doi = 10.1.1.31.6774 & rep = rep1 & type = pdf> Model Checking C Programs Using F-Soft, Proceedings of the 2005 International Conference on Computer Design <http: // portal. acm. org / citation. cfm? id = 1097556 & dl = ACM & coll = portal>

  An object of the present invention is to provide an error trace simplification system that saves labor for referring to an error trace obtained when a source code verification method is applied to the source code of a computer program.

  An error trace simplification system according to the present invention includes a flattening unit that flattens input source code, a source code verification unit that verifies the flattened source code and creates an error trace, and the created error trace. In the case where an operation by a conditional operator is included in the steps included in, an error trace simplification unit that simplifies to a format not including an operation by a conditional operator is provided.

  The error trace simplification method of the present invention includes flattening input source code, verifying the flattened source code, creating an error trace, and steps included in the created error trace. On the other hand, in the case of including an operation by a conditional operator, it includes simplification to a format not including an operation by a conditional operator.

  The program of the present invention flattens input source code, verifies the flattened source code, creates an error trace, and performs conditional operations on the steps included in the created error trace. When a calculation by a child is included, this is a program for causing a computer to execute simplification to a format that does not include a calculation by a conditional operator.

  In the source code verification process using flattening, the expression included in the error trace is simplified, and an error trace that is easy for the user to output can be output.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  Referring to FIG. 1, the error trace simplification system of the present invention includes an input source code 1, a processing device 2, a storage device 3, and a simplified error trace 4.

  As an example of the error trace simplification system of the present invention, a computer such as a PC (personal computer), a thin client terminal / server, a workstation, a mainframe, and a supercomputer is assumed. The system is not limited to a terminal or a server, and may be a relay device or a peripheral device. The system may be an expansion board or software installed in a computer. Furthermore, this system may be a virtual machine (Virtual Machine (VM)) environment mounted on a computer. However, actually, it is not limited to these examples.

  The input source code 1 is a source code to be subjected to source code verification. FIG. 2 illustrates the contents of the input source code 1.

  The processing device 2 operates under program control. As an example of the processing apparatus 2, a processing apparatus such as a CPU (Central Processing Unit) or a microprocessor (microprocessor), or a semiconductor integrated circuit (Integrated Circuit (IC)) having a similar function may be considered. The processing device 2 may be a program for causing a computer to execute the error trace simplification method of the present invention. However, actually, it is not limited to these examples.

  The storage device 3 stores information. Examples of the storage device 3 include a semiconductor storage device such as a memory, an external storage device (storage) such as a hard disk, or a storage medium (media). The storage device 3 may be an external storage device or a network storage server. However, actually, it is not limited to these examples.

  The simplified error trace 4 is a processing result in the error trace simplification system of the present invention.

  The processing device 2 includes a source code input unit 21, a flattening unit 22, a source code verification unit 23, an error trace simplification unit 24, and a result output unit 25.

  The source code input unit 21 reads the input source code 1 and passes it to the flattening unit 22.

  The flattening unit 22 flattens the input source code 1 and passes it to the source code verification unit 23. Here, the flattening unit 22 flattens the input source code 1 as shown in FIG. 2 to create a flattened source code (flattened code) as shown in FIG. 3, and the flattened source The code (flattened code) is transferred to the source code verification unit 23.

  The source code verification unit 23 applies the source code verification to the flattened source code (flattened code), and stores the obtained error trace in the error trace storage unit 31 of the storage device 3. That is, the source code verification unit 23 creates an error trace according to the source code verification method based on the flattened source code (flattened code).

  The error trace simplification unit 24 simplifies the storage device 3 while simplifying all steps included in the error trace stored in the error trace storage unit 31 of the storage device 3 when including operations by a conditional operator. Stored in the error-error trace storage unit 32. An operation by a conditional operator is represented by “conditional expression? True expression: false expression”. That is, the calculation by the conditional operator includes three elements: a conditional expression, a true expression, and a false expression. The error trace simplification unit 24 determines whether the conditional expression is true or false based on the value of the variable in the corresponding step, and the true expression selected by the determination result and the conditional operator or false By leaving only the formula, the components of the formula are reduced.

  Note that the error trace simplification unit 24 may be an apparatus provided independently of the processing apparatus 2. For example, the error trace simplification unit 24 may be a server that can access a plurality of storage devices 3. Further, the error trace simplification unit 24 may be included in a terminal or a server having the storage device 3.

  The result output unit 25 outputs the error trace stored in the simplified error trace storage unit 32 of the storage device 3 as the simplified error trace 4.

  The storage device 3 includes an error trace storage unit 31 and a simplified error trace storage unit 32.

  The error trace storage unit 31 holds information on each step executed until an error occurs. Specifically, as shown in FIGS. 4A, 4B, and 4C, the information held in the error trace storage unit 31 includes the line number on the source code corresponding to the step, and the substitution performed at the step. An expression, a conditional expression that is evaluated and established in the step, and a value of a variable in the step. Although there are various standards for counting the number of steps, in many cases, the value is based on “LOC” (Lines Of Code) which is the number of lines of the source code of the program. LOC may be used as the number of steps as it is, but conversion may be performed by removing the number of blank lines and comment lines that do not make sense as a program from LOC.

  The simplified error trace storage unit 32 basically holds the same content as the content of the error trace storage unit 31 (information of each step executed until an error occurs). However, the simplified error trace storage unit 32 holds the steps including the calculation by the conditional operator after being simplified. That is, the simplified error trace storage unit 32 stores an error trace in which a step not including an operation by a conditional operator is transcribed. For example, the simplified error trace storage unit 32 stores the error trace stored in the error trace storage unit 31 when the error trace stored in the error trace storage unit 31 does not include a step including a calculation by a conditional operator. Is stored as it is. On the contrary, if the error trace stored in the error trace storage unit 31 includes a step including an operation by a conditional operator, the simplified error trace storage unit 32 converts the error trace into the error trace simplification unit 24. And stored after being simplified by the error trace simplification unit 24.

  5 and 6 show the states of the steps included in the error trace shown in FIGS. 4A, 4B, and 4C before and after the simplification. Here, in order to simplify the explanation, only the step in which the expression changes after simplification, that is, the step including the calculation by the conditional operator is shown. FIG. 5 shows steps included in the error trace before simplification stored in the error trace storage unit 31. FIG. 6 shows steps included in the simplified error trace stored in the simplified error trace storage unit 32. However, actually, steps other than the step including the calculation by the conditional operator are also shown.

  Next, the operation of the error trace simplification system of the present invention will be described in detail with reference to FIG.

(1) Processing procedure A1
The source code input unit 21 reads the input source code 1 and passes it to the flattening unit 22. An example of the input source code 1 delivered to the flattening unit 22 is as shown in FIG. Here, the source code input unit 21 acquires the input source code 1 via an input device, a communication interface, or the like. The source code input unit 21 may receive the input source code 1 from an external computer. Alternatively, the source code input unit 21 may read the input source code 1 from an external storage device or storage medium (media).

(2) Processing procedure A2
Next, the flattening unit 22 flattens the input source code 1 and passes it to the source code verification unit 23. For example, when receiving the input source code 1 shown in FIG. 2 from the source code input unit 21, the flattening unit 22 flattens and, as a result, flattened source code (flattened code) having the form shown in FIG. 3. Create and pass to the source code verification unit 23.

(3) Processing procedure A3
Next, the source code verification unit 23 verifies the flattened source code (flattened code).

(4) Processing procedure A4
The source code verification unit 23 determines whether an error trace is obtained in verification of the flattened source code (flattened code). When an error trace is obtained as a result of the verification of the flattened source code (flattened code), the source code verification unit 23 stores it in the error trace storage unit 31. For example, when the source code verification unit 23 verifies the flattened source code (flattened code) shown in FIG. 3, the error trace shown in FIGS. 4A, 4B, and 4C is obtained. The contents (error traces shown in FIGS. 4A, 4B, and 4C) are stored in the error trace storage unit 31. In the verification of the flattened source code (flattened code), an error trace cannot be obtained if no error is detected. If the error trace is not obtained, the source code verification unit 23 ends the process.

(5) Processing procedure A5
Next, the error trace simplification unit 24 simplifies the obtained error trace. For example, the error trace simplification unit 24 reads the error trace stored in the error trace storage unit 31, simplifies the read error trace, and stores it in the simplified error trace storage unit 32. Note that the error trace simplification unit 24 may receive the obtained error trace directly from the source code verification unit 23. Details of the error trace simplification will be described later.

(6) Processing procedure A6
Next, the result output unit 25 outputs the error trace stored in the simplified error trace storage unit 32 as the simplified error trace 4. Note that the result output unit 25 may receive the simplified error trace directly from the error trace simplification unit 24 and output it as the simplified error trace 4.

  Since the obtained simplified error trace 4 does not include the calculation by the conditional operator by the processing of the processing procedure A5 (error trace simplification) in FIG. 7, the user of the present system uses the conditional operator. The error trace can be referenced with little effort without interpreting the operation.

  Next, error trace simplification (processing procedure A5 in FIG. 7) will be described in detail with reference to FIG.

(1) Processing procedure B1
The error trace simplification unit 24 performs the processes from the process procedure B2 to the process procedure B6 in FIG. 8 for all steps included in the error trace stored in the error trace storage unit 31 in the error trace simplification process. It repeats and it transcribe | transfers to the simplification error trace memory | storage part 32. FIG. In the error trace examples shown in FIGS. 4A, 4B, and 4C, step numbers 1 to 55 are repeated step by step. Here, the error trace simplification unit 24 checks whether there is an unprocessed step in the error trace stored in the error trace storage unit 31. At this time, the error trace simplification unit 24 may acquire the error trace directly from the source code verification unit 23 and check whether there is an unprocessed step in the acquired error trace. The error trace simplification unit 24 is configured so that the error trace simplification unit 24 calculates 1 for all steps included in the error trace stored in the error trace storage unit 31 when an unprocessed step is included in the error trace. Read step by step. In other words, the error trace simplification unit 24 reads out the step formulas corresponding to the step numbers 1 to 55 step by step in the example of the error trace shown in FIGS. 4A, 4B, and 4C.

(2) Processing procedure B2
The error trace simplification unit 24 determines whether the expression of the step (read step) includes an operation by a conditional operator. That is, the error trace simplification unit 24 determines whether or not the expression of the step includes an expression represented by “conditional expression? True expression: false expression”.

(3) Processing procedure B3
The error trace simplification unit 24 evaluates the conditional expression part of the operation by the conditional operator based on the value of the variable in the step and determines its true / false when the operation of the conditional operator is included in the expression of the step. To do. For example, the error trace simplification unit 24 assumes that the error trace shown in FIGS. 4A, 4B, and 4C is stored in the error trace storage unit 31 and processes the step of step number 45 by a conditional operator. Since this includes an operation, this branch becomes yes, and the conditional expression part of the operation by the conditional operator is evaluated based on the value of the variable in the step, and its true / false is determined.

(4) Processing procedure B4
If the determination result is false, the error trace simplification unit 24 replaces the entire calculation by the conditional operator with an expression corresponding to the false expression according to the result. As a result, the calculation by the conditional operator is not included in the expression of the step.

(5) Processing procedure B5
If the determination result is true, the error trace simplification unit 24 replaces the entire operation by the conditional operator with an expression corresponding to the true expression according to the result. As a result, the calculation by the conditional operator is not included in the expression of the step.

(6) Processing procedure B6
The error trace simplification unit 24 transcribes the information after replacing the entire calculation by the conditional operator to the error trace (simplified error trace 4) for storing in the simplified error trace storage unit 32. . The error trace simplification unit 24 transcribes the information of the step as it is to the error trace to be stored in the simplified error trace storage unit 32 when the calculation of the conditional operator is not included in the formula of the step. . For example, the error trace simplification unit 24 assumes that the error trace shown in FIGS. 4A, 4B, and 4C is stored in the error trace storage unit 31 and processes the step of step number 1 by using a conditional operator. Since the calculation is not included, the information of the step is directly transferred to the error trace for storing in the simplified error trace storage unit 32. In other words, the error trace simplification unit 24 transcribes information on a step that does not include an operation by a conditional operator in the step expression into an error trace for storing in the simplified error trace storage unit 32.

(7) Processing procedure B7
The error trace simplification unit 24 stores an error trace to be stored in the simplified error trace storage unit 32 when there are no unprocessed steps for all the steps included in the error trace stored in the error trace storage unit 31. Is stored in the simplified error trace storage unit 32, and the process ends. Note that the error trace simplification unit 24 stores in the error trace storage unit 31 when all the expressions of the steps included in the error trace stored in the error trace storage unit 31 do not include an arithmetic operation by a conditional operator. The error trace is stored in the simplified error trace storage unit 32 as an error trace to be stored in the simplified error trace storage unit 32 as it is, and the process is terminated. At this time, the error trace simplification unit 24 outputs the error trace to be stored in the simplified error trace storage unit 32 directly to the result output unit 25 without storing it in the simplified error trace storage unit 32. May be. Here, the error trace stored in the error trace storage unit 31 may be read as the error trace acquired from the source code verification unit 23.

  As a result, the expression of the step transferred to the error trace stored in the simplified error trace storage unit 32 becomes a simplified form in which the true / false judgment of the conditional expression has already been completed.

  Here, with reference to FIG. 9, the details of the processing procedures B2, B3, B4, and B5 will be described using the step number 45 in FIG. 4C as an example.

  The formula 4501 in FIG. 9 is a transcription of the formula at step number 45 in FIG. 4C. An expression 4501 indicates an operation 45011 by a conditional operator. The calculation 45011 by the conditional operator includes a conditional expression 45012, a true expression 45013, and a false expression 45014. When the expression 4501 in FIG. 9 is seen, since the calculation 45011 by the conditional operator is included, the error trace simplification unit 24 executes the processing procedure B3. That is, the error trace simplification unit 24 evaluates the conditional expression part of the calculation by the conditional operator 45011 based on the value of the variable in the step, and determines its true / false. Since the value of the variable i at step number 45 in FIG. 4C is “1” (“i == 1”), the error trace simplifying unit 24 sets “i == 0” in the conditional expression 45012. Judged to be false. Therefore, the operation 45011 by the conditional operator is replaced by a fake expression 45014 and takes the form of the expression 4502 in FIG.

  An expression 4502 in FIG. 9 shows an operation 45021 by a conditional operator. The calculation 45021 by the conditional operator includes a conditional expression 45022, a true expression 45023, and a false expression 45024. When the expression 4502 of FIG. 9 is seen, since the calculation 45021 by the conditional operator is included, the error trace simplification unit 24 executes the processing procedure B3 again. That is, the error trace simplification unit 24 evaluates the conditional expression part of the calculation by the conditional operator 45021 based on the value of the variable in the step, and determines its true / false. Since the value of the variable i at step number 45 in FIG. 4C is “1” (“i == 1”), the error trace simplification unit 24 determines that “i == 1” in the conditional expression 45022. Judge as true. Therefore, the operation 45021 by the conditional operator is replaced by the true expression 45023 and takes the form of 4503 in FIG.

  An expression 4503 in FIG. 9 shows an operation 45031 by a conditional operator. The calculation 45031 by the conditional operator includes a conditional expression 45032, a true expression 45033, and a false expression 45034. Even if the expression 4503 in FIG. 9 is seen, since the calculation 45031 by the conditional operator is included, the error trace simplification unit 24 executes the processing procedure B3 again. That is, the error trace simplification unit 24 evaluates the conditional expression part of the calculation by the conditional operator 45031 based on the value of the variable in the step, and determines its true / false. Since the value of the variable j of step number 45 in FIG. 4C is “0” (“j == 0”), the error trace simplifying unit 24 determines that “j == 0” in the conditional expression 45032 Judge as true. Therefore, the operation 45031 by the conditional operator is replaced by the true expression 45033 and takes the form of 4504 in FIG.

  When the expression 4504 of FIG. 9 is seen, since the calculation by the conditional operator is not included, the error trace simplification unit 24 ends the processing relating to this step.

  As described above, according to the present invention, when the source code verification method is applied to the source code of the computer program, the work of referring to the obtained error trace is saved. Specifically, the operation by the conditional operator included in the error trace is interpreted based on the value of the variable indicated by the error trace, and a simplified error trace that does not include the conditional operator is presented to the user. Thus, the user can reduce the labor for interpreting the calculation by the conditional operator included in the error trace.

  The error trace simplification system of the present invention outputs an error trace that is easy for the user to understand by simplifying the expression included in the error trace in the source code verification method using flattening.

  First, the error trace simplification system of the present invention is obtained by reading an input source code, flattening the input source code, and applying a source code verification method to the flattened source code (flattened code). Stored error traces in the error trace storage unit.

  Next, the error trace simplification system of the present invention does not include the calculation by the conditional operator when all the steps included in the error trace stored in the error trace storage unit include the calculation by the conditional operator. Simplify to format and store in simplified error trace storage. That is, the conditional operator includes elements of a conditional expression, a true expression, and a false expression. When k, the error trace simplification system of the present invention determines whether the conditional expression is true or false based on the value of the variable in the step, and the true expression selected by the conditional operator, Or leave only false expressions.

  Finally, the error trace simplification system of the present invention outputs the error trace stored in the simplified error trace storage unit as a simplified error trace.

  Thereby, since the user can refer to the simplified error trace without interpreting the calculation by the conditional operator, the effort for referring to the error trace can be reduced.

  As mentioned above, although embodiment of this invention was explained in full detail, actually it is not restricted to said embodiment, Even if there is a change of the range which does not deviate from the summary of this invention, it is contained in this invention.

FIG. 1 is a block diagram showing a configuration example of an error trace simplification system of the present invention. FIG. 2 is a diagram illustrating an example of the contents of the input source code. FIG. 3 is a diagram illustrating an example of the content of a flattened source code (flattened code). FIG. 4A is a diagram illustrating an example of step numbers 1 to 20 of information of each step included in the error trace. FIG. 4B is a diagram illustrating an example of step numbers 21 to 40 of information of each step included in the error trace. FIG. 4C is a diagram illustrating an example of step numbers 41 to 55 of information of each step included in the error trace. FIG. 5 is a diagram illustrating an example of steps included in the error trace before simplification stored in the error trace storage unit. FIG. 6 is a diagram illustrating an example of steps included in the simplified error trace stored in the simplified error trace storage unit. FIG. 7 is a flowchart showing the operation of the error trace simplification system of the present invention. FIG. 8 is a flowchart showing a detailed operation of the error trace simplification. FIG. 9 is a diagram for explaining an example of simplification of error tracing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Input source code 2 ... Processing apparatus 21 ... Source code input part 22 ... Flattening part 23 ... Source code verification part 24 ... Error trace simplification part 25 ... Result output part 3 ... Storage device 31 ... Error trace storage part 32 ... Simplified error trace storage unit 4 ... Simplified error trace

Claims (12)

A flattening unit for flattening the input source code;
A source code verification unit that verifies the flattened source code and creates an error trace;
If the step included in the created error trace includes an operation by a conditional operator, the error trace simplification unit includes an error trace simplification unit that simplifies to a format not including the operation by the conditional operator. System. The error trace simplification system according to claim 1,
The operation by the conditional operator is
A conditional expression for determining whether it is true or false based on the value of the variable in the step;
A true expression selected when the conditional expression is true;
An error trace simplification system including a false expression selected when the conditional expression is false. The error trace simplification system according to claim 2,
The error trace simplification unit determines whether a conditional expression in the calculation by the conditional operator is true or false based on the value of the variable in the step, and the conditional operator is determined according to a determination result. An error trace simplification system that replaces the operation by using either a true expression or a false expression in the operation by the conditional operator. An error trace simplification system according to claim 3,
The error trace simplification unit, when the replaced operation is an operation based on the conditional operator, the replaced operation based on the value of the variable in the step with respect to the replaced operation. It is determined whether a conditional expression in a subsequent operation is true or false, and the replaced operation is changed into a true expression and a false expression in the replaced operation according to a determination result. Replace with one of the error trace simplification systems. Flatten the input source code,
Verifying the flattened source code and creating an error trace;
An error trace simplification method comprising: simplifying the step included in the created error trace to a format that does not include the operation by the conditional operator when the operation by the conditional operator is included. An error tracing simplification method according to claim 5,
The operation by the conditional operator is
A conditional expression for determining whether it is true or false based on the value of the variable in the step;
A true expression selected when the conditional expression is true;
An error trace simplification method including a false expression selected when the conditional expression is false. The error trace simplification method according to claim 6,
Based on the value of the variable in the step, it is determined whether a conditional expression in the calculation by the conditional operator is true or false, and the calculation by the conditional operator is performed according to the determination result. A method for simplifying error tracing, further comprising replacing one of a true expression and a false expression in an operation by. The error trace simplification method according to claim 7,
When the replaced operation is an operation based on the conditional operator, the conditional expression in the replaced operation is true based on the value of the variable in the step with respect to the replaced operation. Or replacing the operation after the replacement with either a true expression or a false expression in the operation after the replacement according to the determination result. Including error trace simplification method. Flatten the input source code,
Verifying the flattened source code and creating an error trace;
A program for causing a computer to execute simplification to a format that does not include an operation by a conditional operator when an operation by a conditional operator is included in the steps included in the created error trace. The program according to claim 9, wherein
The operation by the conditional operator is
A conditional expression for determining whether it is true or false based on the value of the variable in the step;
A true expression selected when the conditional expression is true;
A program including a false expression selected when the conditional expression is false. The program according to claim 10,
Based on the value of the variable in the step, it is determined whether a conditional expression in the calculation by the conditional operator is true or false, and the calculation by the conditional operator is performed according to the determination result. A program that further causes a computer to execute replacement with either a true expression or a false expression in an operation by. The program according to claim 11,
When the replaced operation is an operation based on the conditional operator, the conditional expression in the replaced operation is true based on the value of the variable in the step with respect to the replaced operation. Or replacing the operation after the replacement with either a true expression or a false expression in the operation after the replacement according to the determination result. A program that causes a computer to execute.

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