JPH04256132A - Optimization system for substitute sentence of high level program language - Google Patents

Abstract

PURPOSE:To improve the executing performance of a program. CONSTITUTION:A variable allocation address setting means 3 sets a variable allocation address, i.e., an allocation address of a declared variable in a variable allocation address store area 6 in a name table 5. A variable allocation length setting means 4 sets the variable allocation length in a variable allocation length store area 8 in the table 5. A substitute sentence token saving means 12 saves a substitute sentence token into a substitute sentence token saving area 25. Then a block substitute intermediate language text generating means 13 substitute plural substitute sentences for the single one and sets the variable allocation address and the variable allocation length in en intermediate language operand text 14.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to an optimization method for assignment statements in high-level programming languages, and in particular, the present invention relates to an optimization method for assignment statements in high-level programming languages. The present invention relates to an assignment statement optimization method for high-level programming languages that replaces consecutive assignment statements with one assignment statement.

0002

2. Description of the Related Art Conventionally, in high-level programming languages, when a plurality of assignment statements for assigning a constant to a variable exist in succession, a plurality of assignment instructions are output.

0003

[Problem to be Solved by the Invention] In the conventional high-level programming languages mentioned above, optimization is not performed when there are multiple consecutive assignment statements that assign a constant to a variable. Even when it is possible to replace ``with'' a single assignment statement, there is a drawback that execution performance deteriorates because multiple assignment instructions are output.

An object of the present invention is to provide an assignment statement optimization method for a high-level programming language that can improve program execution performance.

[0005]

[Means for Solving the Problems] The optimization method for assignment statements in a high-level programming language of the present invention is applicable to cases where a plurality of assignment statements that assign a constant to a variable exist consecutively in a source program of a high-level programming language. , is an assignment statement optimization method for high-level programming languages that improves program execution performance by replacing multiple assignment statements with a single assignment statement when a compiler compiles the program, wherein: (A) compiler declaration data; The name table created by the name table creation section in the processing section has a variable allocation address storage area and a variable allocation length storage area, and furthermore, the variable allocation address storage area and the variable allocation length storage area are included in the intermediate language operand text generated by the intermediate language text generation section. It has an address storage area and a variable allocation length storage area, and has an assignment statement token save area that holds assignment statement tokens input by the intermediate language text generation section. (B) variable allocation address setting means for setting a variable allocation address that is the allocation address of the variable declared in the variable allocation address storage area in the name table; Variable allocation length setting means for setting a certain variable allocation length; (C) an assignment statement that inputs an executable statement token and saves the assignment statement token to the assignment statement token save area in an assignment statement processing section that processes the assignment statement; token saving means, (D) referring to the name table and the assignment statement token saving area, replacing multiple assignment statements with one assignment statement, and assigning a variable to the variable assignment address storage area in the intermediate language operand text; The apparatus further comprises block assignment intermediate language text generation means for setting an address and setting a variable allocation length in a variable allocation length storage area in the intermediate language operand text.

[0006]

Embodiments Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of an assignment statement optimization method for a high-level programming language according to the present invention.

As shown in FIG. 1, the assignment statement optimization method for the high-level programming language of this embodiment consists of a declaration data processing section 1, an intermediate text generation section 10, an object generation section 19, and a declaration data processing section 1, which are part of the compiler. A declaration data token 20 which is a token for a statement, an executable statement token 21 which is a token for an executable statement, a name table 5 created for each declaration of each variable in the source program, and an intermediate language generated by the intermediate language text generation unit 10. It consists of an operand text 14, an assignment statement token save area 25 where executable statement tokens of assignment statements are saved, an intermediate language text file 22 where intermediate language text is stored, and an object file 24 where objects are stored.

Furthermore, the declaration data processing section 1 has a name table creation section 2, and the name table creation section 2 has variable allocation address setting means 3 and variable allocation length setting means 4.
It is composed of:

The name table 5 also includes a variable allocation address storage area 6 and a variable allocation length storage area 8.

Further, the intermediate language text generation section 10 includes an assignment statement processing section 11, and the assignment statement processing section 11 includes an assignment statement token saving means 12 and a block assignment intermediate language text generation means 13. There is.

[0012] Furthermore, the intermediate language operand text 14 is
It is configured to include a variable allocation address storage area 15 and a variable allocation length storage area 17.

Next, the operation will be explained.

In FIG. 1, when the compiler is activated, the declaration data processing unit 1, intermediate language text generation unit 10, and object generation unit 19 are activated in sequence.

When the declaration data processing section 1 is activated, the name table creation section 2 is activated, and further, the variable allocation address setting means 3 and the variable allocation length setting means 4 are activated in sequence from the name table creation section 2.

The name table creation unit 2 inputs a declaration data token 20 having information on declared variables, and creates a name table 5 from the input variable information as shown in FIG.
Create. Then, variable allocation address setting means 3
determines the allocation addresses 7 of the variables in the order in which they are declared, and sets them in the variable allocation address storage area 6 in the name table 5. Further, the variable allocation length setting means 4
The length information of the declared variable is obtained from the declaration data token 20 and set as the variable allocation length 9, which is set in the variable allocation length storage area 8.

Furthermore, when the intermediate language text generation section 10 is activated, the assignment statement processing section 11 is activated, and further, the assignment statement token saving means 12 and the block assignment intermediate language text generation means 13 are sequentially executed from the assignment statement processing section 11. will be activated.

The assignment statement token saving means 12 receives an executable statement token 21 and saves the assignment statement token to an assignment statement token save area 25 while the input executable statement is an assignment statement. The block assignment intermediate language text generation means 13 sequentially refers to the assignment statement tokens saved in the assignment statement token save area 25, and when referenced, the variable assignment address 7 in the name table 5 for the variable to be assigned. Obtain variable allocation length 9 and save assignment statement token area 25
It is determined whether the variables to which the assignment statement tokens saved in are assigned are consecutive in memory. To determine whether they are consecutive in memory, use the expression (allocation address of the variable to be assigned in the n-th assignment statement + allocation length of the variable to be assigned in the n-th assignment statement) and (n+allocation length of the variable to be assigned in the n-th assignment statement). When the assigned variables (allocated addresses) are equal,
Assume that they are contiguous in memory.

When the variables to which the assignment statement tokens saved in the assignment statement token save area 25 are assigned are continuous in memory and all the data to be assigned are constants, the assignment statement tokens saved in the assignment statement token save area 25 are saved to the assignment statement token save area 25. Replace all assigned assignment statement tokens with one assignment statement token. Intermediate operand text 14 is generated for the variable to be assigned to that one assignment statement token.

The variable allocation address storage area 15 and the variable allocation length storage area 17 in the intermediate language operand text 14 each contain the variable allocation address 16 of the variable to be assigned in the first assignment statement in the assignment statement token save area 25.
The variable allocation length 18 is the sum of the allocation lengths of all assigned variables in the assignment statement token save area 25.
Set as . The length of the data assigned by the reduced assignment statement is the same as the variable allocation length 18 of the variable to which it is assigned. Then, it is output to the intermediate language text file 22 as constant text.

The object generating section 19 inputs the intermediate language text and outputs the object to the object file 24.

[0022] In this way, when compiling, the compiler determines whether or not multiple assignment statements can be replaced with one assignment statement when there are multiple assignment statements that assign constants to variables, and performs the replacement. If possible, program execution performance can be improved by replacing multiple assignment statements with one assignment statement.

[0023]

[Effects of the Invention] As explained above, the method for optimizing assignment statements in a high-level programming language of the present invention allows the compiler to perform multiple assignment statements that assign a constant to a variable when there are multiple consecutive assignment statements during compilation. The effect is that program execution performance can be improved by determining whether an assignment statement can be replaced with one assignment statement, and if so, replacing multiple assignment statements with one assignment statement. have.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of an assignment statement optimization method for a high-level programming language of the present invention.

FIG. 2 is a diagram showing details of a name table in the assignment statement optimization method of the high-level programming language of this embodiment.

[Explanation of symbols]

1 Declaration data processing section 2 Name table creation section 3 Variable allocation address setting means 4 Variable allocation length setting means 5 Name table 6 Variable allocation address storage area 7 Variable allocation address 8 Variable allocation length storage area 9 Variable allocation length 10 Intermediate text generation Part 11 Assignment statement processing unit 12 Assignment statement token saving means 13 Block assignment intermediate language text generation means 14
Intermediate language operand text 15 Variable allocation address storage area 16 Variable allocation address 17 Variable allocation length storage area 18 Variable allocation length 19 Object generation unit 20 Declaration data token 21 Executable statement token 22 Intermediate language text file 24 Object file 25 Assignment statement token save area

Claims (1)

[Claims] [Claim 1] When a source program of a high-level programming language contains multiple consecutive assignment statements that assign a constant to a variable, when the compiler compiles the program, the multiple assignment statements are combined into one assignment. replace with the sentence,
This is an assignment statement optimization method for high-level programming languages that improves program execution performance, and includes: (A) variable allocation address storage area and variable It has an allocated length storage area,
Furthermore, the intermediate language operand text generated by the intermediate language text generation unit has a variable allocation address storage area and a variable allocation length storage area, and an assignment statement token save area that holds the assignment statement token input by the intermediate language text generation unit. (B) variable allocation address setting means for inputting a declaration data token and setting a variable allocation address that is an allocation address of the declared variable in the variable allocation address storage area in the name table; Variable allocation length setting means for setting the variable allocation length that is the allocation length of the variable declared in the variable allocation length storage area in the name table; (C) Inside the assignment statement processing unit that inputs the executable statement token and processes the assignment statement. (D) an assignment statement token saving means for saving assignment statement tokens to the assignment statement token save area; block substitution intermediate language text generation means for replacing, setting a variable allocation address in a variable allocation address storage area in the intermediate language operand text, and setting a variable allocation length in a variable allocation length storage area in the intermediate language operand text; An assignment statement optimization method for a high-level programming language characterized by the following.