JPH0381829A - Static variable reference system having initial value of high-ranking - Google Patents

Abstract

PURPOSE:To reduce the whole size of a static variable allocating area by providing a system with a name table classification setting means, an initial value information setting means, a data updating information setting means, a name table classification changing means, and so on. CONSTITUTION:The name table classification setting means 3 inputs a declaration data token 14 and sets up a name table classification 8 to be the classification of a variable declared in a name table classification storing area 7. The initial value information setting means 4 sets up the initial value information 10 of the token 14 in an initial value information storing area 9 and the data updating information setting means 5 inputs an execution sentence token 15 and sets up data updating information 12 in a data updating information storing area 11. The name table classification changing means 6 inputs the information 12 set up in the storing means 11, decides whether a static variable can be changed to a constant or not and changes the classification 8 set up in the area 7 by the means 3 to the sort 8 indicating a constant having the initial value information 10 as its value. Consequently, the whole size of the static variable allocating area can be reduced.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method in which a high-level language compiler refers to a static variable that has an initial value at the time of compilation, and particularly relates to a method in which a static variable is referenced as a constant without being allocated to memory. .

[Conventional technology]

Conventionally, static (STATI) had this kind of initial value.
C) Variables were always referenced as data allocated to memory.

[Problem to be solved by the invention]

The conventional method of referencing 5TATIC variables with initial values described above necessarily allocates the 5TATIC variables to memory, which are frequently updated, so as the number of 5TATIC variables increases, the memory size allocated to the 5TATIC variables also increases. The disadvantage is that it increases.

[Means to solve the problem]

The static variable reference method having an initial value for a high-level language program of the present invention includes a declaration data processing unit, and when compiling a high-level language source program in which a state variable having an initial value is declared, the static variable In the static variable reference method that has an initial value of a high-level language program that refers to, initial value information of the static variable that has the initial value in a name table created by the name table creation unit of the declaration data processing unit. It has an initial value information storage area that stores the name table type, a name table type storage area that stores the name table type, and a data update information storage area that stores the data update information that is the update information of the declared variable. name table type setting means for inputting a token and setting a name table type that is a type of a variable declared in the name table type storage area; and initial value information for setting the initial value information in the initial value information storage area. a setting means; a data update information setting means for inputting an executable statement token and setting data update information in the data update information storage area; and data update information set in the data update information storage area by the data update information setting means. a name table type changing means for inputting a static variable, determining whether a static variable can be changed to a constant, and changing the name table type set in the name table type storage area by the name table type setting means to a type representing a constant; We are prepared.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention.

Referring to FIG. 1, one embodiment of the present invention includes a declaration data processing unit 1 which is a part of a compiler, and name tables 13a to 13 created for each declaration of each variable in a source program.
d, declaration data token 14, which is a token for a declaration statement; executable statement token 1, which is a token for an executable statement;
Consists of 5.

Furthermore, the declaration data processing unit 1 includes the name table creation unit 2.
, data update information setting means 5, and name table type changing means 6.

Further, the name table creation section 2 includes a name table type setting means 3 and an initial value information setting means 4.

The name tables 13a to 13d are composed of a name table type storage area 7, an initial value information storage area 9, and a data update information storage area 11.

Next, the flow of processing will be explained.

In FIG. 1, when the declaration data processing section 1 is activated, the name table creation section 2, data update information setting means 5, and name table type changing means 6 of the declaration data processing section 1 are activated in sequence. Further, the name table type setting means 3 and the initial value information setting means 4 of the name table creation section 2 are sequentially activated.

Then, the name table creation unit 2 inputs the declaration data token 14 having information on the declared variables, creates name tables 13a to 13d from the input variable information, and clears the data update information storage area 11. Furthermore, the name table type setting means 3 sets the variable allocation status from the declaration data token 14 to the name table type storage area 7 as name table type 8. In addition, the initial value information setting means 4
sets the initial value information 10 in the declaration data token 14 to the initial value information storage area 9 in the name tables 13a to 13d. If no initial value exists for the variable, information about no initial value is set in the initial value information storage area 9.

The data update information setting means 5 inputs an executable statement token 15, and when the input executable statement is a statement that updates the contents of a variable, the name table 13a to 1 for that variable is input.
3d and sets data update information 12 indicating that the variable has been updated in the data update information storage area 11 in the name tables 13a to 13d. The name table type changing means 6 inputs all the name tables 13a to 13d, and the name table type 8 stored in the name table type storage area 7 represents a 5TATIC variable, and the name table type 8 stored in the name table type storage area 7 represents a 5TATIC variable, and the initial value information storage area 9 Initial value information 10 exists, and
When the data update information 12 in the data update information storage area ll indicates that the variable has not been updated, the name table type 8 in the name table type storage area 7
is changed to name table type 8, which indicates that it is a constant having initial value information 10 as a value.

In this way, the compiler creates 5TATIC with initial values.
Determine whether the variable can be referenced as a constant, and if it is, refer to the 5TATIC variable as a constant without allocating it to memory.
Variable allocation can reduce the total size of the area. Furthermore, since there is no need to refer to memory, the execution performance of the target program can be improved.

〔Effect of the invention〕

As explained above, the present invention allows the compiler to determine whether or not a 5TATIC variable with an initial value can be referenced as a constant, and if it can be referenced as a constant, the compiler refers to the 5TATIC variable as a constant without allocating it to memory. This has the effect that 5TATIC variable allocation can reduce the total size of the area.

[Brief explanation of drawings]

FIG. 1 shows the constituent countries of one embodiment of the present invention. l...Declaration data processing unit, 2...Name table creation unit, 3...Name table type setting means, 4...Initial value information setting means, 5...
... Data update information setting means, 6... Name table type changing means, 7... Name table type storage area, 8... Name table type, 9...・
・Initial value information storage area, 10...Initial value information, 1
1... Data update information storage area, 12...
・Data update information, 13... Name table, 1
4...Declaration data token, 15...
Executable statement token.

Claims (1)

[Claims] When compiling a high-level language source program that includes a declaration data processing unit and in which static variables with initial values are declared, static variables with initial values of the high-level language program that refer to the static variables. In the reference method, the name table created by the name table creation unit of the declaration data processing unit includes an initial value information storage area for storing initial value information of a static variable having the initial value, and a name table type. It has a name table type storage area for storing name table type storage areas and a data update information storage area for storing data update information that is update information of declared variables, and inputs a declaration data token and displays the declared variables in the name table type storage area. a name table type setting means for setting a name table type which is a type of a variable; an initial value information setting means for setting the initial value information in the initial value information storage area; inputting an executable statement token and updating the data; a data update information setting means for setting data update information in an information storage area; and inputting the data update information set by the data update information setting means into the data update information storage area, and determining whether a static variable can be changed to a constant. and name table type changing means for changing the name table type set in the name table type storage area by the name table type setting means to a type representing a constant. Static variable reference method.