JPH02195438A - Recursive access detecting system in microdevelopment - Google Patents

Abstract

PURPOSE:To correctly develope the reculsive access detection of a macro name based upon an ordinary method without using recursive access even when a practically developed result is extremely large by setting up the maximum number of retrievals as the total definition number of macro names. CONSTITUTION:A source program is inputted from an undeveloped source program file by a source program input means 3, and when a macro name is included in the inputted source program, a macro developing means 4 retrieves macros in a macro definition area 1 so that the number of macros concerned does not exceeds the total definition number and obtains the result of the macro development concerned. The result is outputted to a source program film 8 by a source program output means 5. When no macro is searched in the area, the means 4 outputs an error. The shown diagram indicates the developing procedure of the means 4 and the area 1 consists of a macro name storing area 6 and a counter indicating the total definition number of macro names.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a recursive call detection method in macro expansion, and more particularly to a recursive call detection method in macro expansion in compiler processing.

(Prior Art) Conventionally, this type of macro expansion processing has been part of compiler processing, and has been used to process constants, names,
Define expressions as a macro, which is a logical set,
By referring to this macro name, it is possible to write it in place of these constants, names, expressions, etc.

In this method, the method for detecting infinite references when recursively calling a macro name is to store the result of expansion in the expansion area when expanding the macro, as shown in Figure 2 (a) and Figure 2 (b). The method was to detect an error when the expansion result did not fit within the expansion area.

That is, in FIG. 2, in the macro expansion process, the source program from the unexpanded source program file 2 is inputted via the source program input means 3, and if it is determined that macro expansion is not necessary, the source program is inputted to the source program output means 5.
The source program is output. On the other hand, if it is determined that macro expansion is necessary, the macro expansion means 7 searches the macro definition area 1 and temporarily expands the corresponding macro.
It is stored in the expansion area, and if there is expansion that exceeds the area, an error will occur. The source program of 1mf& is output to the source program file 8 after being expanded.

In this manner, the conventional macro expansion means 7 has an expansion area for storing macro expansion results, and when the expanded results cannot be stored in this area, it is assumed that a recursive call is performed.

(Problem to be Solved by the Invention) In the conventional method of detecting recursive calls in macro expansion described above, recursive calls are detected based on whether or not the expansion result fits in the expansion area. However, even if the result of simple expansion, rather than a recursive call, does not fit in the expansion area, an error will occur, and there is a drawback that it depends on the size of the expansion r#J area.

In addition, a macro declaration in which a macro reference ends up referencing itself as shown in Figure 2 (C) has the disadvantage that recursive calls cannot be detected if there is no expansion result stored in the expansion area. be.

(Means for Solving the Problems) The recursive call detection method in macro expansion according to the present invention treats constants, names, expressions, etc. that appear in a source program as a logical set called one macro, and defines this set as one macro. By defining a name called a macro name and writing the macro name instead of the constant, name, expression, etc., you can create a constant,
In a recursive call detection method in macro expansion of a compiler that allows references to names, expressions, etc., recursive calls to the macro name are limited by a predetermined total number of definitions of the macro name during macro name reference processing.

(Example) Next, one embodiment of the present invention will be described using the drawings.

FIG. 1(a) is a diagram showing the configuration of a recursive call detection method in macro expansion according to the present invention, and shows an overview of macro expansion processing, which is a part of compiler processing.

When a source program is inputted from the source program file 2 before expansion using the source program input means 3, and if there is a macro name in the input source program, the macro expansion means 4 inputs the corresponding macro into the macro definition area 1, with the total number of definitions. The search is performed within a range not exceeding , the result of corresponding macro expansion is obtained, and this result is outputted to the source program file 8 after expansion by the source program output means 5. The macro expansion means 4 determines an error if it cannot be found by the above-mentioned range search.

FIG. 1(b) shows the expansion method in the macro expansion means 4, where the macro definition area 1 is the macro name storage area 6.
and a counter indicating the total number of defined macro names. X=VAL5 shown in this example is X=V in the first expansion
The result is AL6, and in the second expansion, X = VAL5, which would be repeated infinitely in the normal processing method, but in this processing method, by setting the maximum number of expansions to the total number of times the macro name is defined, infinite repetition is not possible. This detects recursive calls in macro name expansion.

FIG. 1(C) shows an example of the macro definition area 1 and the unexpanded source program file 2 in FIG. 1(a). In this example, 6 of macro definition area 1lil11
In the definition of lines 0 and 70, VAL5. VAL6 indicates a recursive invocation of a macro name that eventually refers to itself. Therefore, source program file 2 before expansion
The 1000th line of '30M=1000+2000;'
However, the 1100th line cannot be expanded because of the recursive call.

(Effects of the Invention) As explained above, according to the present invention, the recursive call detection of macro names, which depends on the size of the expansion area in the conventional method, is performed by setting the maximum number of searches to the total number of macro name definitions. This has the effect that no matter how large the actual expansion result is, it can be expanded correctly without making it a recursive call, and it is possible to detect recursive calls in declarations where the macro name ends up being itself. There is.

[Brief explanation of the drawing]

FIG. 1(a) is an overall diagram of the recursive call detection method according to the present invention, and FIG. 1(b) is a diagram of the macro name storage area 6 for explaining the contents of the macro expansion means 4 in FIG. 1(a). The detailed diagram, FIG. 1(c), is a diagram showing an example of macro definition 1 and source program 2 in FIG. 1(a), and FIG.
a) is a diagram showing an overview of conventional macro expansion processing, and Figure 2 (
b) is a diagram showing the conventional macro expansion means 7 shown in FIG. 2(a). 1... Macro definition area, 2... Source program file before expansion, 3... Source program input means, 4
．． 7.9... Macro expansion means, 5... Source program output means, 6... Macro name storage area details diagram, 8.
- Source program file after expansion.

Claims (1)

[Claims] The constants, names, expressions, etc. that appear in a source program are defined as a logical set called a macro, and this set is defined by a name called a macro name, and instead of the constants, names, expressions, etc. By writing macro names, constants, names,
In a recursive call detection method in macro expansion of a compiler that enables referencing of expressions, etc., the recursive call of the macro name is limited by a predetermined total number of definitions of the macro name during macro name reference processing. A recursive call detection method for macro expansion.