JP2727996B2 - Program execution monitoring method and program execution monitoring system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a program execution monitoring method, and more particularly to a program execution monitoring method and a program execution monitoring system for monitoring an infinite loop state in a loop portion in a program.

[0002]

2. Description of the Related Art Conventionally, in this type of technology, for example, in the technology described in Japanese Patent Application Laid-Open No. 57-90767 as a first prior art, a breakpoint is provided at an arbitrary position in a program and the program passes through the breakpoint. When the number of times reaches a predetermined number, it is determined that the program is in an infinite loop.

A second prior art is disclosed in Japanese Patent Laid-Open No.
In the technique described in Japanese Patent Application Laid-Open No. 05233, an interrupt routine is started each time a branch instruction appears, and when the branch by the branch instruction and the immediately preceding branch are performed between the same addresses, the number of loops is reduced by one. When the number of loops exceeds a predetermined limit value, it is determined that the program is in an infinite loop.

[0004]

In the above-mentioned first prior art, a breakpoint is set at a place where a loop may occur, and a limit value of the number of times of passing through the breakpoint is set in advance. As the program gets larger, this setting itself becomes less easy. Also,
The determination as to whether or not a loop often depends on the data input to the program, and it is difficult to set in advance the limit values corresponding to all data in the program. Further, the first prior art cannot deal with a loop in a place where a breakpoint is not set. In other words, it is difficult to find a loop because it occurs in an unpredictable place, and in reality, it is often impossible to identify in advance the location where the loop occurs.

In the above-described second embodiment, it is not necessary to set a breakpoint, but it is necessary to set a limit value for judging whether or not the loop is an infinite loop in the first embodiment. It has the same problem as the example. Further, in the second prior art, only one pair of a pre-branch address and a post-branch address is held. Therefore, when an infinite loop is formed by a plurality of branches, this is detected. Can not. For example, if a certain process is performed after branching from address A to address B and then branching from address C to address A, a branch from address A to address B is followed by a branch from address C to address A. Is determined to have left the loop at the time when the error occurs, and an infinite loop state cannot be detected.

It is an object of the present invention to eliminate the need for setting a breakpoint and setting a limit value for determining whether or not an infinite loop exists in a program execution monitoring method.

Another object of the present invention is to make it possible to monitor the execution state of a program even when an infinite loop is formed by a plurality of branch instructions.

[0008]

In order to solve the above-mentioned problems, a program execution monitoring method according to the present invention stores history information on a branch that occurred during execution of a program, and analyzes the history information after the execution of the program. By doing so, the place where the infinite loop occurs is specified.

According to another program execution monitoring method of the present invention, there is provided a processing device for executing a program, a storage device including a branch history storage unit for storing a history of branches generated during execution of the program, and a method for externally storing data. In a program execution monitoring system having an input device for inputting and a display device for displaying data, a step of generating an interrupt indicating that a branch has been detected during program execution, and a branch instruction that has generated the branch Retrieving whether or not information relating to the branch instruction is already registered in the branch history storage unit; and, if the information of the corresponding branch instruction is already registered in the branch history storage unit, increasing the number of branches of the branch instruction. If the information of the corresponding branch instruction is not already registered in the branch history storage unit, the information on the branch instruction is stored in the branch history storage unit. Comprising a step of registering, the steps of resuming execution of the program, and displaying on said display means to edit the information stored in the branch history storage unit in accordance with an instruction from the input means to the end of the program.

The program execution monitoring system according to the present invention comprises a program executing means for executing a program, an interrupt receiving means for receiving an interrupt indicating that a branch has been detected by the program executing means, and a branch instruction for generating the branch. Search means for searching whether or not information relating to a branch instruction is already registered in the branch history storage unit, and if the information is already registered, a search means for increasing the number of times of branching; A registration unit for newly registering the information in the branch history storage unit when it is not registered in the branch history storage unit; an interruption ending unit for notifying the program execution unit of a program execution restart instruction; Editing means for editing the content stored in the section and displaying it on the display means.

In another program execution monitoring method and a program execution monitoring system according to the present invention, the information on the branch instruction includes a branch destination address, and the display means displays the number of branches for each branch destination address.

Further, in another program execution monitoring method and program execution monitoring system according to the present invention, the information on the branch instruction includes a branch destination address and a branch instruction address, and the display means displays the branch destination address for each branch instruction. Displays the number of branches.

In another program execution monitoring method and program execution monitoring system according to the present invention, the information on the branch instruction includes a branch destination address and a branch instruction type identification code, and the display means branches for each type of the branch instruction. Displays the number of branches for the destination address.

[0014]

Next, an embodiment of a program execution monitoring method according to the present invention will be described in detail with reference to the drawings.

Referring to FIG. 1, a program execution monitoring method according to an embodiment of the present invention includes a processing device 100 for processing data, a storage device 200 for storing data, and a keyboard used by a user for inputting. The present invention is realized in a program execution monitoring system having a display device 300 for displaying figures and texts.

The storage device 200 includes a branch history storage unit 210 that stores a history of branches that have occurred in the processing device 100.

The processing device 100 includes a program execution unit 110 for executing a program, an interrupt reception unit 120 for receiving an interrupt indicating that a branch has been detected by the program execution unit 110, and a branch history storage unit 210 for storing the generated branch. A search unit 130 for searching whether or not a registered branch is already registered in the branch history storage unit 210
Registration means 140 for newly registering if not registered in
And an interrupt ending means 150 for notifying the program executing means 110 of the end of the interrupt to restart the program, and an editing means 160 for editing the contents stored in the branch history storage unit 210 and displaying the contents on the display device 400. Have.

The program execution means 110 normally executes each instruction in the program in order. When detecting the occurrence of a branch due to a branch instruction during the execution of a program, the program execution means 110 generates an interrupt and temporarily suspends the execution of the program. This interrupt is received by the interrupt receiving means 120, and the program is not executed until a series of interrupt processing ends. The instruction to restart the program is issued by the interrupt ending means 150. Here, a series of interrupt processing means the interrupt receiving means 1 described above.
20, the search means 130, the registration means 140, and the interruption end means 150.

The interrupt receiving means 120 receives a branch detection interrupt in the program executing means 110. Then, as shown in FIG. 2, an instruction address 203, an instruction code 202, and a branch destination address 201 of the branch instruction that caused the interrupt are received as branch information, and the branch information is provided to the search unit 130. The branch destination address 201 and the branch instruction address 203 may be logical addresses or physical addresses. The instruction code 202 is for determining the type of the branch instruction, and may take the part of each instruction code in the program as it is, or may be in a compressed form as long as it can be determined.

The search means 130 is provided by the interrupt receiving means 12
A search is performed to determine whether the branch information given from 0 is already registered in the branch history storage unit 210 in the storage device 200. Referring to FIG. 3, the branch history storage unit 210 in the storage device 200 has a plurality of entries, and each entry includes a branch destination address 211, an instruction code 212, and a branch instruction Address 213,
And the number of branches 214. Among them, the branch destination address 211, the instruction code 212, and the branch instruction address 213 are the branch destination address 20 of the branch information.
1, instruction code 202 and branch instruction address 20
3 respectively. The number of branches 214 counts how many times the corresponding branch has occurred in the past.

The search means 130 includes a branch history storage unit 210
Are searched for an entry that matches the branch information provided by the interrupt receiving means 120. At this time, the comparison target is the branch destination address 21
1, instruction code 212, and branch instruction address 21
3. As a search method, a method of sequentially performing a match comparison from the first entry, a method of performing hashing using a part of the branch destination address 211 as a key, and the like can be considered.

The search means 130 includes a branch history storage section 210
When an entry that matches the branch information is detected, the value of the branch count 214 of that entry is incremented by one.

The registration unit 140 newly registers the branch information in the branch history storage unit 210 when the corresponding entry is not searched by the search unit 130. As a result, the branch destination address 201, the instruction code 202, and the branch instruction address 203 of the branch information are stored in the branch destination address 211, the instruction code 212, and the branch instruction address 213 of the new entry, respectively.
The number of times of branch 214 is set to “1”.

When the registration means 140 secures a new entry, if there is an empty entry, one of the empty entries is arbitrarily selected and used. If a certain number of entries are prepared more than the number of branch instructions appearing in the program, it can be dealt with by a method of sequentially registering from the first entry. When all the entries have been used, it is conceivable to use a technique called “use a recently unused entry as a new entry”, which is generally called an LRU method, such as a cache memory. Can be

When the search means 130 and the registration means 140 have been completed, the interruption ending means 150 instructs the program execution means 110 to resume the execution of the program.

The editing means 160 includes the program executing means 1
After the execution of the program in 10 is completed, the contents of the branch history storage unit 210 are edited according to the instruction from the user using the keyboard, and the result is displayed on the display device 400. In this editing process, for example, if the number of branches is indicated for each branch destination address, it is possible to easily recognize which instruction has caused many branches.
You can know the cause of the infinite loop.

It is needless to say that the keyboard 300 may be another input means such as a mouse or a touch panel. Needless to say, the display device 400 may be another output unit such as a printer device.

Next, the operation of the embodiment of the present invention will be described.

When a branch detection interrupt occurs in the program executing means 110, the interrupt is accepted by the interrupt accepting means 120. Referring to FIG. 4, a search process is performed in an interrupt routine (step 131).
That is, as described above, the search unit 130 determines whether or not the branch information provided from the interrupt receiving unit 120 has already been registered in the branch history storage unit 210, that is, whether or not there is an entry that matches the content of the branch information. Or search.

As a result, when a matching entry is detected, the value of the branch count 214 of the entry is increased by one (step 133). Conversely, if no matching entry is detected, registration processing is performed on the branch information (step 141). This registration process is realized by newly registering the branch information in the branch history storage unit 210 by the registration unit 140 as described above.

When the processing in step 133 or step 141 is completed, the interrupt ending means 150 instructs the program execution means 110 to resume the program execution.

In this way, when the execution of the program progresses and then ends normally, or when the program is manually terminated or abnormally terminated after exceeding a predetermined time,
The branch history storage unit 210 stores the branch history of the program. The user enters the keyboard 300
When the instruction to display the branch history is issued by the
0 edits the contents of the branch history storage unit 210 and displays the result on the display device 400. That is, referring to FIG. 5, the editing processing by the editing means 160 is performed in step 161, and then the display on the display device 400 is performed in step 162.

Referring to FIG. 6, in an example of a program to be subjected to the present invention, there is a branch from x to c as an innermost loop, a branch from y to b as an outer loop, and a branch from y to b. It is assumed that a branch from z to a can occur as an outer loop.

Referring to FIG. 7, in the example of the display of the branch history when the program of FIG. 6 is executed, the horizontal axis direction is the branch destination address, and the vertical axis direction indicates the number of branches to the corresponding address. ing. The results in FIG. 7 show that the number of branches for b is extremely large. As a result, the user can make a prediction that an infinite loop is generated for the branch to b as a reason why the program does not end normally.

Further, the user can further instruct the keyboard 300 to display the instruction address of the branch instruction which caused the branch for the branch destination address "b". As a result, a screen display is obtained in which the horizontal axis represents the branch instruction address and the vertical axis represents the number of branches from the branch instruction to the branch destination address “b”. As a result, if the number of branches from the branch instruction address “y” is extremely large, it is highly possible that an infinite loop is formed between the branch instruction address “y” and the branch destination address “b”. You can judge.

There are several types of branch instructions.
For example, there are a conditional branch instruction that determines whether or not to branch according to the value of a certain variable, an unconditional branch instruction that branches unconditionally, and a branch instruction that specifies the number of times to form a loop according to a predetermined counter value. By designating the types of these branch instructions, the user can also help analyze an infinite loop.

As described above, according to the program execution monitoring method of one embodiment of the present invention, the program execution means 11
When the occurrence of a branch is detected at 0, an interrupt is generated, and the history of the branch that occurred in the past is stored in the branch history storage unit 210 to set a breakpoint or determine whether or not the loop is an infinite loop. And the execution state of the program can be monitored even when an infinite loop is formed by a plurality of branch instructions.

In the above embodiment, the branch destination address, the instruction code, and the branch instruction address are used as the branch information and the branch history, but they need not always be used simultaneously. This is because the execution state of the program can be known only by storing the branch destination address. The reason for using the branch instruction address in the above embodiment is that
This is for detailed analysis of a specific branch pattern in which a branch source and a branch destination are paired. Therefore, if there is no such request, this branch instruction address is unnecessary.
The reason why the instruction code is used in the above embodiment is to analyze operations having different properties for each type of branch instruction. Therefore, if there is no such request, this instruction code is unnecessary.

[0039]

As is apparent from the above description, according to the present invention, it is not necessary to set a breakpoint or to set a limit value for judging whether or not an infinite loop exists. Even if it is formed,
The execution status of the program can be monitored.

[Brief description of the drawings]

FIG. 1 is a diagram showing a functional configuration of an embodiment of a program execution monitoring method according to the present invention.

FIG. 2 is a diagram showing information on a branch instruction in one embodiment of the present invention.

FIG. 3 is a diagram showing the contents of a branch history storage unit in one embodiment of the present invention.

FIG. 4 is a diagram showing a search registration procedure of the program execution monitoring method according to one embodiment of the present invention.

FIG. 5 is a diagram showing an edit display procedure of the program execution monitoring method according to one embodiment of the present invention.

FIG. 6 is a diagram illustrating an example of a program that is an object of the present invention.

FIG. 7 is a diagram showing a display example on a display device according to an embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 processing device 110 program executing means 120 interrupt accepting means 130 searching means 140 registering means 150 interrupt ending means 160 editing means 200 storage device 210 branch history storage unit 300 keyboard 400 display device

Claims (5)

(57) [Claims] 1. A processing device for executing a program, a storage device including a branch history storage unit for storing a history of branches generated during execution of the program, an input device for externally inputting data, and displaying data Generating an interrupt indicating that a branch has been detected during execution of a program, and information relating to the branch instruction that caused the branch has already been registered in the branch history storage unit. And if the information of the corresponding branch instruction is already registered in the branch history storage unit, increase the number of times of the branch instruction, and store the information of the corresponding branch instruction in the branch history. Registering information on the branch instruction in the branch history storage unit if the information is not already registered in the storage unit; Steps and the program execution monitoring method characterized by editing the information stored in the branch history storage section according to an instruction from said input means after the end of the program and displaying on said display means for opening. 2. The program execution monitoring method according to claim 1, wherein the information on the branch instruction includes a branch destination address, and the display unit displays the number of branches for each branch destination address. 3. The program according to claim 1, wherein the information on the branch instruction includes a branch destination address and a branch instruction address, and the display unit displays, for each branch instruction, the number of branches for the branch destination address. Execution monitoring method. 4. The information on the branch instruction includes a branch destination address and a branch instruction type identification code, and the display unit displays the number of branches for the branch destination address for each type of the branch instruction. The described program execution monitoring method. 5. A program executing means for executing a program, an interrupt receiving means for receiving an interrupt indicating that a branch has been detected by the program executing means, and information on a branch instruction which caused the branch is stored in the branch history storage unit. A search means for searching whether or not the information has already been registered, and increasing the number of times of the branch if the information has been already registered; and information about the branch instruction which caused the branch when the information has not been registered in the branch history storage unit. Registration means for newly registering the program in the branch history storage unit; interrupt ending means for notifying the program execution means of a program execution restart instruction; and editing the contents stored in the branch history storage unit after the program ends. A program execution monitoring system, comprising: an editing unit for displaying on a display unit.