JPH0232425A - Constant optimizing system - Google Patents

Abstract

PURPOSE:To execute the high speed constant optimization by storing a constant and a hash value with a hash table and using the constant stored corresponding to the same hash value as the hash value of the constant to appear in a source program. CONSTITUTION:When a compiler 2 is activated with a source program 1, the compiler 2 starts to translate the source program 1. When a constant appears during the translation of the source program 1, a constant optimizing means 3 is activated. The activated constant optimizing means 3 obtains the appeared constant hash value and searches a hash table 4 based on the obtained hash value. At the time of obtaining the same hash value, the constant corresponding to the hash value in the hash table 4 is used. By repeating the above-mentioned action each time the constant appears, the high speed constant optimization is executed and an object module 5 can be prepared.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a constant optimization method, and more particularly to a constant optimization method in the target program generation process of a compiler.

[Conventional technology]

Conventionally, in this type of constant optimization method, when allocating a constant, the constant to be allocated is compared with the already allocated constant one after another, and if the same constant already exists, the constant to be allocated is not allocated and the constant is already allocated. I was trying to use the given constant.

[Problem to be solved by the invention]

In the conventional constant optimization method described above, when searching whether a constant to be allocated is the same as a constant that has already been allocated, the constant to be allocated is compared with the allocated constant one after another. , the disadvantage is that it takes time to search.

In view of the above points, an object of the present invention is to provide a constant optimization method that performs constant optimization at high speed by using a hash table.

[Means to solve the problem]

The constant optimization method of the present invention is a constant optimization method in which when allocating a constant in a source program, if the same constant has already been allocated, the constant is not allocated and the already allocated constant is used. Search the hash table to store the hash value and the hash table for the hash value of the constant that appears when the constant appears in the source program. and constant optimization means using correspondingly stored constants.

[Effect]

In the constant optimization method of the present invention, the hash table stores constants and their hash values, and the constant optimization means calculates the hash values of the constants that appear when the constants appear in the source program and stores them in the hash table. If the same hash value is found, the stored constant corresponding to that hash value is used.

〔Example〕

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

FIG. 1 is a block diagram showing the configuration of a constant optimization method according to an embodiment of the present invention.
Consisting of a source program 1 as an input, a compiler 2, a constant optimization means 3 included in the compiler 2, a hash table 4 used by the constant optimization means 3, and an object module 5 generated by the compiler 2. has been done.

Referring to FIG. 2, the processing in the constant optimization means 3 includes a hash value calculation step 31, a hash table search step 32, an identical hash value determination step 33, a hash table constant use step 34,
Constant allocation consists of step 35 and hash table registration step 36.

Next, the operation of the constant optimization method of this embodiment configured as described above will be explained.

When the compiler 2 is started using the source program 1, the compiler 2 starts translating the source program l.

If a constant appears during translation of source program 1,
Constant optimization means 3 is activated.

The activated constant optimization means 3 calculates the hash value of the constant that appears (step 31), and searches the hash table 4 based on the calculated hash value (step 32). Next, the constant optimization means 3 determines whether or not there is the same hash value in the hash table 4 (step 33), and if there is the same hash value, the hash value in the hash table 4 is determined. (Step 34)
If the same hash value does not exist, the constant that appears is assigned (step 35), and the obtained hash value and the constant that appears are registered in the hash table 4 (step 36).

The constant optimization means 3 repeats the above operations every time a constant appears, thereby performing constant constant optimization at high speed and finally generating an object module 5.

〔Effect of the invention〕

As explained above, by using a hash table when optimizing constants, the present invention can perform a high-speed search for the same constant, which in turn enables high-speed constant optimization. effective.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a constant optimization method according to an embodiment of the present invention, and FIG. 2 is a flowchart showing processing in the constant optimization means in FIG. In the figure, 1: source program, 2: compiler, 3: constant optimization means, 4: hash table, 5: object module.

Claims (1)

[Claims] In a constant optimization method in which when allocating a constant in a source program, if the same constant has already been allocated, the constant is not allocated and the already allocated constant is used, the constant and its hash value a hash table for storing constants; and a hash table for searching the hash table for the hash value of the constant that appears when the constant appears in the source program, and if the same hash value is found, the hash value is stored corresponding to that hash value. 1. A constant optimization method, comprising a constant optimization means using a constant.