JP3045083B2 - Storage area management device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a storage area management device in an apparatus for automatically synthesizing a program by rewriting input specification data expressed in a tree structure in a programming language, a specification description language, or the like according to a set of rewrite rules.

[0002]

2. Description of the Related Art When a data structure represented by a tree structure is rewritten using a set of rewrite rules, an unnecessary data structure that is not referred to from anywhere by the rewrite occurs. The storage area recovery device recovers a storage area occupied by an unnecessary data structure from the storage area into a usable storage area again, thereby efficiently using the storage area. In the related art, when recovering an unnecessary data structure from a storage area, the entire storage area currently being used is scanned, and a storage area that is not included in the scanned area in the entire storage area is unnecessary. It was being collected as a storage area.

FIG. 10 shows a data structure expressing a tree structure in a storage area, and a specific example of an input represented thereby.
The tree structure is expressed using a data structure represented by a value of the tree node and a pointer indicating the tree node in the storage area. Using this data structure, the tree structure is expressed by substituting a function symbol for the value of each node and a pointer to a subtree for the pointer, and establishing a link.

FIG. 11 shows a specific example of a rewrite rule and an example of an input data structure rewritten by the rewrite rule. By applying the rewriting rule 301, the input data structure represented by the tree structure is rewritten. In the figure, c, f, g, and h represent function symbols, and X and Y represent variables. In this example, the function symbol c
Represents an operation of rewriting a tree composed of h into a tree composed of h. As a result of the application of the rewrite rule 301, a data structure appearing on the right side of the rewrite rule is newly secured in the storage area, and an area that becomes unnecessary as a result of the rewrite remains as an area that is not referenced from anywhere in the storage area.

FIG. 12 shows a specific example of collecting a storage area.
Although the data structure representing the tree structure is conceptually a tree structure as shown on the left side of the figure, the storage area on the computer is stored in a continuous storage area 310 as shown on the right side of the figure. The areas of the structure are connected by pointers.

While rewriting is repeated, the storage area 310
In the case where the usable area becomes small in the storage area, the storage area management device for reclaiming the storage area scans all the currently used tree structures from the root of the tree of the input data structure, thereby obtaining the currently used tree structure. A mark is attached to the storage area (hatched part in the figure). Next, the entire storage area 310 is scanned, the unmarked part is collected as an unnecessary area part 311 and the storage area 310 is reused.

[0007]

In the conventional storage area management apparatus described above, when finding an unnecessary storage area from a storage area, all of the currently used areas are searched for, so that the storage area can be searched for in the storage area. The area currently in use and the unnecessary area were distinguished. Therefore, every time the storage area is collected, it is necessary to perform a search over all the used areas,
There is a problem that it takes time to collect the storage area.

An object of the present invention is to analyze a rewrite rule in advance, to extract an invariant portion that is not rewritten by execution of rewrite from a rewrite target, and to store this portion as an invariable portion in a storage area in advance. By taking advantage of the fact that the invariable part does not become an unnecessary area, the time required for scanning the storage area in use is shortened, thereby realizing a high-speed recovery processing of the storage area. It is an object of the present invention to provide a storage area management device capable of performing the above.

[0009]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a storage area management device for an apparatus for automatically synthesizing a program by rewriting an input specification expressed in a tree structure by a set of rewriting rules. A rewriting rule analyzing means for extracting, from the left side, information for detecting data which is likely to be rewritten by the rewriting rule and data which is not likely to be rewritten among the input specifications, a first area and a second area A storage area for storing the input specification expressed in the tree structure separately from the area, and a data portion which is not rewritten by the rewrite rule in the input specification based on information from the rewrite rule analysis means. Storage area allocation for storing in a first area of a storage area and storing a data portion to be rewritten in a second area of the storage area And the step, by scanning the second region of the storage area, characterized in that it comprises a recovery means for recovering unwanted tree structure data of the storage area generated by the execution of the rewriting.

In the storage area management apparatus according to the present invention, the rewriting rule analyzing means extracts one left side from the rewriting rule, determines whether the left side has a function symbol structure, and If it is a symbol structure, by repeating the process of adding a function symbol to a set of function symbols that may be rewritten, all the function symbols appearing on the left side of the rewriting rule are added to the set, and the obtained set Is a set of function symbols that can be rewritten by the left side of the rewrite rule, and the storage area allocating means is a function in which the function symbol of the input specification represented by the tree structure is obtained by the rewrite rule analyzing means. Judge whether it belongs to a set of symbols, and if so, make the tree-structured data by the function symbol data that can be rewritten. To as data having no possibility of being rewritten tree structure data by the function number symbols, stored in the first region and the second region of the storage area.

According to a third aspect of the present invention, the rewriting rule analyzing means determines whether the argument of the function symbol has a function symbol structure, and if the function symbol has a function symbol structure, rewrites the argument. It is characterized in that a process of adding to a set of possible function symbols is repeated.

[0012]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows the configuration of an automatic software synthesis apparatus to which the present invention is applied. As shown in FIG. 1, this software automatic synthesizing apparatus is an apparatus that receives a program specification 11 as an input and outputs a program 12, and includes a syntax analysis unit 14, an output unit 15,
It comprises a rewrite rule application unit 16, a storage area management unit 17, and a rewrite rule compiler 18.

The input program specification 11 is converted into a syntax tree 13 by using a syntax analyzer 14. Syntax tree 13
Is rewritten using the rewrite target search / rewrite rule application unit 16, and when there is finally no rewrite target, the output unit 16 generates the program 12.

The rewriting rule 110 is a rule for rewriting a subtree of the syntax tree 13 and is compiled by a rewriting rule compiler 18 into a rewriting function 19 for actually executing rewriting.

The storage area management unit 17 manages a storage area required to store the syntax tree 13 and a storage area required to store the result of rewriting by the rewrite target search / rewrite rule application unit 16. As shown in FIG. 2, the storage system includes a storage area allocation unit 21, a storage area 22, a rule analysis unit 23, and a collection unit 24.

The storage area 22 is a section which secures a storage area for expressing a syntax tree on a computer. The storage area 22 includes an invariable section 221 for allocating and storing a non-rewritable portion, and a rewritable portion. Is divided into variable sections 222, which are areas for assigning and storing parts having potential.

The storage area allocating section 21 includes the syntax analyzing section 1
4 and the rewrite target search / rewrite rule application unit 16 allocates an area necessary for expressing the syntax tree 13 to the storage area unit 22. As shown in FIG. The area is the invariable part 2 of the storage area 22
An invariable part allocating unit 211 that allocates and stores the same to
The area for the part that may be rewritten is the storage area 2
And a variable unit allocating unit 212 that allocates and stores the variable units to the two variable units 222. This storage area allocating unit 21
When the storage area 22 is exhausted, the collection unit 24 is called to execute a collection process of the area part of the storage area 22 that is no longer referred to from anywhere.

The rule analysis unit 23 receives the left side of the rewrite rule from the rewrite rule compiler 18 and passes a function symbol appearing when performing pattern matching in the rewrite rule to the storage area allocating unit 21.

In the configuration of the storage area management section 17 described above, the storage area allocation section 21 receives the input specification from the syntax analysis section 14 and, when reserving an area of the storage area section 22, specifies a function symbol appearing in pattern matching. Since the included part may be rewritten, the variable part allocating part 212
Is stored in the variable section 222 of the storage area 22, and the other non-rewritable portions are stored in the variable section allocating section 2.
11 to the invariable part 221 of the storage area 22.

The recovery unit 25 scans the area of the storage area 22 in order to detect a subtree that is not referred to from the storage area 22. The storage area 22 is divided into an invariable section 221 and a variable section 222 in advance. Since the area of the invariable section 221 is not rewritten according to the rewriting rule, scanning of the storage area 22 is performed only for the variable section 222. I just need. As a result, the storage area to be scanned can be reduced, and the speed for the collection process is increased.

Next, specific embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 3 shows a specific example of the rewriting rule 110. The rule shown in FIG. 3 is based on the function symbol “ap” in the input specification.
This is a rule for rewriting the tree represented by “pend”, where uppercase alphanumeric characters (X, Y, Z) in the figure represent variables, and rewriting unifies the left side of the rewriting rule with the input specification, and By applying the conversion operator to the right side, it is made a rewrite result.

The rule analysis unit 26 of the storage area management unit 17 shown in FIG. 2 receives the left side of the rewrite rule 110 from the rewrite rule compiler 18 and performs analysis according to the procedure shown in the flowcharts of FIGS. .

First, a set P for registering a pattern of a function symbol appearing in a rewrite rule is initialized (step 40).
1), the set on the left side of the rewrite rule is assigned to the set R (step 402). Next, one left side of the rule is extracted from the set R and is substituted for L (step 40).
3). Here, based on the L, a second process shown in FIG. 5, which is a process for extracting a portion that may be subjected to pattern matching, is called (step 404).

As shown in FIG. 5, in the second process, it is determined whether or not L is a structure of a function symbol f (arg1, arg2,..., Argn), that is, a conditional branch is performed based on the L structure (step 501), if the pattern is a pattern in which a function symbol appears, the function symbol f is added to the set P (step 502). Next, the same processing is repeated for the argument of the function symbol (step 503), and all the function symbols appearing on the left side of the rewrite rule are added to the set P.

When the second processing is completed, L is removed from the set R (step 405). Steps 403 to 40 for the set R until the processing is performed for all the left sides
Step 5 is repeated (step 406). All sets R
The set P is obtained as a result of performing the repetitive processing (step 407). The obtained set P is a set of function symbols that may be rewritten by the set R on the left side of the rewriting rule 110.

FIG. 6 shows an analysis result of the rewrite rule shown in FIG. 3 analyzed by the analysis method shown in FIGS. In this example, "append" and "con" are function symbols that may be rewritten by the left side of the rewriting rule.
Three function symbols “s” and “nil” are obtained.

The storage area allocating section 21 of the storage area management section 17 has a syntax analysis section 14 for performing syntax analysis of the input specification 11.
The processing shown in the flowchart of FIG.

The storage area allocating section 21 first divides the storage area 22 into an invariable section 221 and a variable section 222 (Step 701). Next, a text expression of the tree structure data to be assigned to the storage area 22 is input from the syntax analyzer 14 (step 702). Then, one function symbol f is extracted from the data (step 703), and the function symbol f
Is included in the set P obtained in FIGS. 4 and 5 (step 704).

If the function symbol f belongs to the set P, the tree structure data created by the function symbol f may be rewritten. Variable part 2 of area 22
When the function symbol f does not belong to the set P, the tree structure data created by the function symbol f is not rewritten.
An area is secured and stored in the invariable part 221 of the storage area 22 using the invariable part allocating part 211 of the storage area allocating part 21 (Step 706). These processes are performed for all inputs (step 707).

FIG. 8 shows an example of the input specification 11 and an example of the data structure expression on the storage area 22. In this example, a data structure including the function symbols “append” and “cons” is stored in the variable section 222 of the storage area 22, and a data structure including other function symbols is stored in the invariable section 22 of the storage section 22.
1 is stored.

FIG. 9 shows an example of collecting the storage area 22. When the rewriting is executed, an unnecessary tree structure data area is generated in the storage area 22. Storage area management device 17
The collection unit 25 scans the storage area 22 in order to collect the unnecessary tree structure data area generated by such rewriting. At this time, the invariable part 2
21 is not rewritten according to the rewriting rule, so that an unnecessary area does not occur. Therefore, by scanning only the variable section 222 in the storage area 22, the currently used area can be changed. It can be specified. Therefore, the storage area 2 during the collection process
Scanning 2 is completed in an extremely short time as compared with scanning the entire storage area 22, and as a result, speeding up of the collection process is realized.

Although the present invention has been described with reference to the preferred embodiments and examples, the present invention is not necessarily limited to the above embodiments and examples.

[0034]

As described above, the storage area management apparatus in the apparatus for automatically synthesizing a program by rewriting input specification data expressed by a tree structure according to the present invention as described above, analyzes the rewriting rules in advance. By storing the part that is not likely to be rewritten by the execution of the rewriting and the part that is likely to be rewritten into the invariable part and the variable part of the storage area, respectively, When scanning the area, it is only necessary to scan the variable portion of the storage area, so it is possible to reduce the area for scanning the area in use. As a result, it is possible to speed up the processing for collecting the storage area. The effect of realizing is obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an automatic software synthesis apparatus to which the present invention is applied.

FIG. 2 is a block diagram illustrating a configuration of a storage area management unit according to the embodiment of the present invention.

FIG. 3 is a diagram showing a specific example of a rewriting rule.

FIG. 4 is a flowchart illustrating a processing procedure of a rewriting rule analysis unit of a storage area management unit.

FIG. 5 is a flowchart showing a second process of the rewriting rule analysis unit of the storage area management unit.

FIG. 6 is a diagram showing a result of analyzing the rewriting rule of FIG. 3 according to the processing procedures of FIGS.

FIG. 7 is a flowchart illustrating a processing procedure of a storage area allocation unit of the storage area management unit.

8 is a diagram showing a specific example in which a storage area is secured according to the processing procedure of FIG. 7;

9 is a diagram illustrating a specific example in a case where the storage area collection processing illustrated in FIG. 8 is performed.

FIG. 10 is a diagram showing an example of a data structure expressing a tree structure and a specific example of a tree structure expressed thereby.

FIG. 11 is a diagram showing a specific example of rewriting tree structure data according to a rewriting rule.

FIG. 12 is a diagram showing an example of a conventional storage area collection process.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Program specification 12 Program 13 Syntax tree 14 Syntax analysis part 15 Output part 16 Rewrite target search / rewrite rule application part 17 Storage area management part 18 Rewrite rule compiler 19 Rewrite function 110 Rewrite rule 21 Storage area allocation part 211 Invariant part allocation part 212 Variable part allocating part 22 Storage area part 221 Invariable part 222 Variable part 25 Collection part 26 Rule analysis part

Continuation of the front page (56) References JP-A-6-251066 (JP, A) JP-A-2-69842 (JP, A) Minoru Tomobe, and two others, "Realization of an automatic software synthesis system based on the term rewriting system"", Information Processing Society of Japan Research Report, November 30, 1995, VOL. 95, NO. 114 (PRO-4), P.E. 13-18 (58) Field surveyed (Int.Cl. ⁷ , DB name) G06F 12/00-12/02 G06F 9/44 G06F 9/06

Claims (3)

(57) [Claims] 1. A storage area management device for an apparatus for automatically synthesizing a program by rewriting an input specification expressed in a tree structure by a rewrite rule set, wherein a rewrite rule of the input specification is rewritten from a left side of the rewrite rule. Rewriting rule analysis means for extracting information for detecting data that is likely to be rewritten and data that is not likely to be rewritten; and an input represented by the tree structure divided into a first area and a second area. A storage area for storing specifications, and a data portion that is not rewritten by the rewriting rule in the input specifications is stored in a first area of the storage area based on information from the rewriting rule analysis means, Storage area allocating means for storing a data portion to be performed in a second area of the storage area, and running in the second area of the storage area By,
A storage area management device, comprising: a recovery unit that recovers unnecessary tree structure data in the storage area generated by execution of rewriting. 2. The rewriting rule analyzing means extracts one left side from the rewriting rule, determines whether the left side has a structure of a function symbol, and rewrites the function symbol if the left side has a function symbol structure. By repeating the process of adding to the set of possible function symbols, all the function symbols appearing on the left side of the rewriting rule can be added to the set, and the obtained set can be rewritten by the left side of the rewriting rule. The storage area allocating means determines whether the function symbol of the input specification represented by the tree structure belongs to the set of function symbols obtained by the rewriting rule analysis means, In such a case, the tree structure data by the function symbol is regarded as data that can be rewritten, and when it does not belong, the tree structure data by the function symbol is rewritten. 2. The storage area management device according to claim 1, wherein data that is not likely to be stored is stored in a first area and a second area of the storage area. 3. The rewriting rule analysis means determines whether an argument of the function symbol has a function symbol structure.
3. The storage area management device according to claim 2, wherein if the structure is a function symbol, a process of adding the function symbol to a set of function symbols that may be rewritten is repeated.