JPS61213936A - Step execution system for high-level language program - Google Patents

Abstract

PURPOSE:To improve the efficiency of debugging by analyzing the statement structure of a high-level language program and storing start positions of statements, etc., and controlling the execution and stop of the program while regarding the start positions as break points. CONSTITUTION:A CPU analyzes the statement structure of the source program in high-level language which is stored in a memory, and store its compiled machine word program in the memory and also generates a statement number table 20 and a statement structure table 30 in the memory. When a command for step execution up to right before a statement in the statement at a stop position is supplied while the program is stopped, a stop position statement number (i) in the source program is checked on the basis of the value of a program counter and the statement number table to take the statement number (j) of the statement in the statement corresponding to the statement number (i) out of the statement structure table 30. The program is executed until the start address of the machine word program which has the statement number (j), then stopped, and debugging result information is displayed on a display device.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a debugging technique for a computer system, and particularly to a step execution method at a high-level language level of a program.

<Summary of the invention> Analyzes the sentence structure of a primary language program and determines the starting position of one sentence,
Detect and memorize the start position of a sentence included in a certain sentence, the start position of a sentence following a certain sentence, and the start position of a sentence that includes a certain sentence, and use these start positions as breakpoints. Control step execution.

<Background of the Invention> A program written in a high-level language is translated into a machine language program by a compiler in advance, and then executed by a computer.

As is well known, one execution of a high-level language is often translated into multiple machine languages.

When debugging a computer system, it is necessary to stop program execution at each high-level language level executable statement of the source program and examine changes in each variable within the program.
Checking the operation by step execution is an important operation.

However, the step execution method in conventional debugging devices is at the machine language level, and an interrupt occurs and stops for each machine language. Therefore, in order to control step execution of one executable statement at the target high-level language level, step execution at the machine language level must be repeated many times.

This consumes extra processing time, which hinders improvements in debugging efficiency.

<Object of the Invention> An object of the invention is to enable direct and efficient step execution at a high-level language level.

<Structure and Effects of the Invention> In order to achieve the above object, the step execution method according to the present invention first analyzes the sentence structure of a high-level language program and determines the starting position of a sentence and the starting position of sentences included in a certain sentence. , the starting position of the sentence following a certain sentence.

It is characterized by detecting and storing the start positions of sentences that include a certain sentence, and controlling execution/stop of the program using the start positions of each of the sentences as breakpoints according to instructions.

According to this step execution method, step execution is performed immediately before the statement contained within a certain statement, step execution is performed immediately before the next statement, and step execution is performed immediately before or to the end of the statement that contains the statement. can be done semi-automatically without having to be particularly aware of breakpoints, which greatly contributes to improving debugging efficiency.

<Embodiment> FIG. 1 is a block diagram of a debugging device to which the present invention is applied. 1 is a CPU that executes debug processing. 2
is the memory in which the program to be debugged is stored. 3 and 4 are key human power devices and display devices as man-machine interfaces. Reference numeral 5 denotes a debug document monitor memory, which is a memory for storing compiled machine language programs and data necessary for debugging. Tables shown in FIGS. 2 and 3, which will be explained below, are also created in the debug monitor memory 5.

When debugging, the CPU 1 first compiles a source program in a high-level language stored in the memory 2, analyzes the sentence structure of the source program, stores the compiled machine language program in the memory 5, and
The sentence number table 20 in the figure and the sentence structure table 30 in Figure 3
and is created in memory 5.

A program written in a high-level language is executed using statements, and one statement represents a single execution unit. In high-level languages, sentences are recursively defined and have a structure that includes sentences within one sentence. In other words, a statement that instructs repeated execution or a statement that makes a conditional judgment is defined using one sentence.A complex sentence defined as a simple sentence is composed of a sequence of statements.

Figure 4 shows an example of a sentence structure. This program consists of statements 1 to 12. Looking at sentence 1,
Sentence 1 includes Sentence 2, Sentence 4, and Sentence 7. Further, sentence 2 includes sentence 3, and sentence 4 includes sentence 5. This sentence 5 further includes sentence 6. For example, looking at sentence 4, sentence 4 is included in sentence 1.

In the statement number table 20 of FIG. 2, each statement number of the source program is associated with the start address and end address of a group of machine language instructions corresponding to each statement in the machine language program.

For each statement number in the source program, the statement structure table 30 in FIG. , and control information.

As control information, information indicating the classification when there are multiple sentence number information, the division sentence of the sentence, etc. is stored,
Used for special cases.

Regarding the example in FIG. 4, the contents of the sentence structure table 30 will be explained with sentence 4 as the main body.The sentences contained within sentence 4 are the sentences contained in sentence 5.
The sentence following sentence 4 is sentence 7, and the sentence that includes sentence 4 is sentence 1.

According to this invention, the following four types of steps can be executed arbitrarily by instructions from the key human power device 3.

a...Step execution up to just before the statement included inside the statement at the stop position B...Step execution up to just before the next sentence of the statement at the stop position C...Including the statement at the stop position Step execution to the end of the sentence containing the sentence d...Step execution to the point immediately before the sentence that includes the sentence at the stop position Figure 4 shows the following steps when the stop position is immediately before (the beginning) of sentence 4. Arrows a and b indicate the destination of the above four types of step execution.
, c, and d.

The value of program counter 1 of the CPUI indicates the position in the machine language program, but which statement number in the source program the counter value corresponds to (position in the source program) is determined by the counter value and the statement number table 20 above. You can understand by comparing and contrasting.

Normally, step execution is performed when the program is stopped.

When, for example, a command to execute step a above is given from the key human power device 3 in the stopped state, the CPUI checks the stop position statement number on the source program from the value of the program counter and the statement number table 20. The sentence number is l
shall be. Next, the item of sentence number i in the sentence structure table 30 is checked, and the sentence number of the sentence that can be discussed inside the sentence of sentence number i is extracted.

Let the sentence number be j. Next, return to the written statement number table 20 and check the start address of statement number j on the machine language program. Let that address be 8j.

Once the address 8j is known, the program is executed in real time up to the machine #i west exit program address Sj and then stopped, and the debug result information is output to the display device 4. The step execution process of b j '#d is also the same as above.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a debugging device to which the present invention is applied, FIG. 2 is a diagram showing a statement number table created for step execution of the present invention, and FIG. 3 is a diagram also showing a statement structure table. FIG. 4 is a diagram showing an example of a sentence structure. 20...Sentence number table, 30...Sentence structure table.

Claims (1)

[Claims] (1) In a device for debugging a program written in a high-level language, the sentence structure of the program is analyzed,
It detects and memorizes the start position of a sentence, the start position of a sentence included in a certain sentence, the start position of a sentence following a certain sentence, and the start position of a sentence that includes a certain sentence, and then A step execution method for a high-level language program, characterized in that execution/stop of the program is controlled using the start position of each of the above statements as a breakpoint.