JPH1021087A - Compiling method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compiling method which has realized an efficient compilation. SOLUTION: This method consists of definitions of several functions, definitions of variables, and declarations of types, and all the names (function name, variable name, and type name) are declared and defined before use in principle, thereby compiling a high-level language. At this time, halfway results of the compilation process are held and when an undefined function is detected in the process of other compilation, a corresponding function is picked up among halfway results held in the compilation and used as the declaration of the function.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compiling method, and more particularly to a technique effective for compiling (translating into a machine language) a C language and a C ++ language.

[0002]

2. Description of the Related Art High-level languages are widely used depending on the purpose, such as for scientific and technical calculations and business calculations, or in a combination of these. There is a large gap between such a high-level language and a machine language actually used for information processing in a computer, and a process for filling the gap is compilation (translation). Such a programming language is described in, for example, "Microcomputer Handbook", pp. 497-532, issued by Ohmsha on December 25, 1985.

The C language, which is one of the high-level languages, was introduced in 1972 by D. Ritchie of Bell Laboratories in the United States as BCP, as shown in the above-mentioned document.
Based on languages such as L and B, TSS (time sharing s) on PDP-11 (minicomputer architecture)
ystem) It is designed as a language for the system UNIX. C language is UNI as a system description language.
It is a language developed with X, and its features are as follows. The C ++ language is an extension of the functions of the C language.

[0006] A compact program can be written by using abundant operators and data types and a control structure for facilitating structural programming, and employing a simple expression method. A program consists of a collection of small modules (= functions) and can be divided and compiled. It can handle bit operations and address pointers, and can describe in a form similar to machine language. It has a preprocessor and can use macro functions. Since it is a small language, processing can be small, and
High portability.

[0005] The C language operators and data types are as follows. The C language has an extremely rich set of operators, in addition to ordinary arithmetic, logical, and relational operators, various operators for bit processing, conditional operators for describing "if-then-else", and object addresses. There is a pointer-related operator such as "&" for extracting the number of bytes, a "sizeof" operator for extracting the number of bytes of an object, a comma operator, an assignment operator, and the like, which enable a simple expression. Certain expressions may have side effects, for example, an operation that assigns a value to a variable causes the side effect of an assignment expression (taking an assigned value as a value). For example, the expression a [i ++] = (x + = 2); has the same effect as x = x + 2; a [i] = x; i = i + 1;

[0006] Variables are classified into four types according to the difference in the description area management method. Declared outside all functions, 1
Variables that serve as global variables in one source file are called external variables (extern). The dynamic variable (auto)
Occurs and disappears each time the function is invoked. In contrast, static variables exist for the duration of a program. A high-speed operation register is assigned to a register variable (register).

The data types of the C language are broadly classified into basic types and composite types. The composite type is constructed recurrently based on the basic data type. The array name is synonymous with the address of the 0th element, and the pointer variable and the array name are treated almost in the same manner, and addition and subtraction and comparison with integers can be performed. For example, the sum of the elements of the array a declared as int a [10] is for (p = a, sum = 0; p <= a + 9; p
++) sum + = ^* p; The type that represents a function is called the function type, and determines the type of the result returned by the function. A collection of variables of some type is a structure
This is a PASCAL record. A variable that holds various data of different types and sizes in a single area is called a union.

[0008] C language statements include a simple statement (an expression followed by ";") and a compound statement (a list of local declarations followed by a statement, and these are enclosed by ｛｝). Block), conditional statement (if-then-else), selection statement (switch), repetition statement (while, fo)
r, do), auxiliary control statements (break, goto, re)
turn, etc.).

A program in the C language is composed of several function definitions, variable definitions, and type declarations.
One program must define a function named "main".
n. A function is a compound statement written after the function name and formal parameters. The parameter binding method for functions is only a call by value, and uses pointers to cause side effects.

A recursive definition is allowed in the definition of a function or a data type definition of a complex type. This allows a simple and clear definition of a function and a dynamic structure having a complicated structure such as a list or a tree. Data structures can be described. In principle, all names are declared or defined before use, and their scope is only within the block in which they are defined (functions are also one block).

[0011]

As described above, since a function to be used must be declared or defined in a program, it is troublesome to change the program. That is, if the function to be used is not declared or defined, an error occurs, and the entire compilation process is redone.

An object of the present invention is to provide a compiling method which realizes efficient compiling. The above and other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

[0013]

The following is a brief description of an outline of a typical invention among the inventions disclosed in the present application. In other words, it consists of several function definitions, variable definitions, and type declarations, and all names (function names, variable names, and type names) must be declared or defined before use. In the language compilation method, the intermediate result of the compilation process is held, and if an undefined function is detected in another compilation process, the corresponding function is picked up from the intermediate result held in the above compilation, and the function is extracted. Use it as a declaration. Declaring a function refers to describing only the name and type of the function that may be used. Defining a function means "declaring a function" and further describing what the function does.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a system configuration diagram of an embodiment for performing a compiling process according to the present invention. Although not particularly limited, the compiler receives a source program written in the C language and the C ++ language and forms an output translated into an object program composed of a machine language by a compiling process. At this time, the compiler uses, for example, a database file to hold information on the declaration of the function, which is a result of compiling in each program.

FIG. 2 shows a PAD (Problem Analysis Diagram) showing an example of a compiling process using information on the declaration of a function stored in the database file.
The figure is shown. The function symbol is read, and it is defined as a function x. If it is a symbol declaration, register x in a database file (1). If it is a symbol reference,
It is determined whether the function x is declared in the source program. If the function x is not declared in the source program (no), the function x is not immediately treated as an error as in the related art. Refers to the information in the database file, and if there is the corresponding function x in the result of compiling with another program, the function x is interpreted as having been declared in the source program. (2) In the figure,
Although omitted, if the function x is not defined in the database file, a function undefined error occurs as in the conventional compilation method.

FIG. 3 shows an example of a source program in C language. In C language, there is no concept of a program line as in BASIC, but for convenience of explanation, description will be given with temporary line numbers as shown in FIGS. In the specification, parentheses are added to the above numbers and are expressed as (4) to (7). int f (void); declares a symbol (function) f (4), and f () refers to it (5). Other symbols (functions) a and b are, for example, i
The reference (6) in a (); and the reference in b (1, 2L); are made without declaration (definition) such as nt a (void); int b (void); ). In the conventional compiling method, if there is an undeclared symbol a or b in the source program, an error occurs, and the int a (voi
d); and int b (void); require declaration of symbols a and b.

However, in the compiling method according to the present invention, when undeclared symbols a and b are detected, the database file is referred to. That is, as shown in FIG. 4A, if a symbol name and an attribute (argument) are registered in a database file by definition in another program, such declaration information is acquired from the database file, and a and b Is interpreted as being already declared in the source program. Therefore, after compiling the source program as shown in FIG. 3, the database file contains the declaration of the symbol f in this program in addition to the symbols a and b already declared in another program as shown in FIG. 4B. Is additionally registered.

The functions and effects obtained from the above embodiment are as follows. (1) Consisting of several function definitions, variable definitions, and type declarations, all names (function names, variable names, and type names) must be declared or defined before use. In the high-level language compilation method, the intermediate result of the compilation process is held, and if an undefined function is detected in another compilation process, the corresponding function is picked up from the intermediate result held in the compilation, and Is used as a function declaration, an effect is obtained that an efficient compilation process can be realized.

(2) According to the above (1), in the development of a program, when a part of the source program is modified or changed, the declaration before the change can be effectively used, and without reviewing all the symbols, Since it is only necessary to declare symbols to be added, it is possible to obtain an effect that the program can be efficiently modified or changed.

Although the invention made by the inventor has been specifically described based on the embodiments, the invention of the present application is not limited to the above embodiments, and various modifications can be made without departing from the gist of the invention. Needless to say. For example, a high-level language consists of several function definitions, variable definitions, and type declarations as described above, and all names (function names, variable names, and type names) must be declared or used before use. Anything can be used as long as it is defined in principle.

[0021]

The effects obtained by typical ones of the inventions disclosed in the present application will be briefly described as follows. In other words, it consists of several function definitions, variable definitions, and type declarations, and all names (function names, variable names, and type names) must be declared or defined before use. In the high-level language compilation method, the intermediate result of the compilation process is held, and if an undefined function is detected in another compilation process, the corresponding function is picked up from the intermediate result held in the compilation, and By using it as a function declaration, efficient compile processing can be realized.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram showing one embodiment for performing a compiling process according to the present invention.

FIG. 2 is a PAD diagram showing an example of a compiling process using the database file shown in FIG. 1;

FIG. 3 is a source program configuration diagram showing an example of the C language for describing the present invention.

FIG. 4 is a symbol configuration diagram showing a recording example of a database file for explaining the present invention.

[Explanation of symbols]

1 ... Symbol registration processing, 2 ... Symbol acquisition processing, 4 ... Symbol declaration, 5-7 ... Symbol reference.

Claims (2)

[Claims] (1) It consists of several function definitions, variable definitions and type declarations. In principle, all names (function names, variable names, type names) are declared or defined before use. In the high-level language compilation method, the intermediate result of the compilation process is held, and if an undefined function is detected in another compilation process, the corresponding function is picked up from the intermediate result held in the above compilation, A compilation method characterized by using it as a function declaration. 2. The compiling method according to claim 1, wherein said high-level languages are C language and C ++ language.