JPS63104141A - Register fixing system - Google Patents

Abstract

PURPOSE:To produce a proper object code at a high speed by using a saving subject common arithmetic result detecting means, a saving position deciding means, a tentative saving code generating means, a common arithmetic result storing register saving deciding means, and a tentative saving code processing means respectively. CONSTITUTION:A saving position deciding means 2 is started by a saving subject common arithmetic result detecting means 1 and then starts a tentative saving code generating means 3 to inform a saving subject TS and a decided saving position. A tentative saving code showing an object code for saving is produced at a saving position informed from the means 3 and inform to an optimizing means. At the same time, a common arithmetic result storing register saving deciding means 4 is started by a register allocating means and checks the tentative saving code and the using state of the corresponding register. Thus it is possible to produce a saving object code to be given to a main memory storing the common arithmetic result in the form of an optimum object code without deteriorating the processing speed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a code generation method for a compiler, and more particularly to an object code generation method in which the results of a common operation are fixed in a specific register and referenced.

(Prior art) Conventionally, in the object code generation method of a compiler, in order to generate efficient object code, the results of common operations in a program are stored in a specific register, and when the results of common operations are referenced, Assume that an object code that refers to the relevant register is generated.

FIG. 4 is an explanatory diagram showing such an object code generation method. In Figure 4, L is load,
MULT is multiplication, ST is store, SUB is subtraction, GRl
represents register 1. In addition, in the object image corresponding to the paper program image indicated by ■, the operation corresponding to 'N+J' is omitted, and the result of 'IXJ' in ■ is referred to by register GR1.

On the other hand, registers are required to perform other operations,
In order to effectively utilize a finite register set, it may be necessary to generate object code that saves registers storing the results of common operations into the main memory.

FIG. 5 is an explanatory diagram showing an example of a method for dealing with such a case. In Figure 5, “l-36J” is ■
This is a common operation in sentences ~■. After a while, ■～
As long as the contents of "J" and "J" do not change between ■, the register storing the result of 'IXJ' of ■
%J", efficient object code can be generated.

However, in generating the object code corresponding to the interval between ■ and ■, it is required to use a large number of registers. Therefore, if a register that stores the result of "I+J" must also be used, it is best to generate an object code that saves the corresponding register immediately after ■.

FIG. 6 is an explanatory diagram showing instruction intermediate code strings corresponding to ① to ② in FIG. 5, respectively, and illustrating a stacking method. In FIG. 6, intermediate code strings of instructions corresponding to a range that refers to the result of a common operation are stacked and searched to generate an optimal object code for saving. In FIG. 6, T1 to T4 each indicate a register.

FIG. 7 is an explanatory diagram showing the evacuation priority method.

Among the registers storing the results of common operations, all registers TS to be saved are used to generate object codes for saving.

In FIG. 7, an object code that saves the result of "I+J" is unconditionally generated at the position (■).

(Problems to be Solved by the Invention) In the conventional register fixing method described above, in the stacking method, firstly, the range in which intermediate code strings can be stacked is limited, so the range in which optimal object code can be generated is limited. Second, it is necessary to re-search the stacked intermediate code string, which has the disadvantage of slowing down the processing speed. , since the object code for saving is generated, there is a drawback that redundant object code is generated.

An object of the present invention is to eliminate the above-mentioned drawbacks by making it possible to generate an object code for saving a register storing the result of a common operation to main memory as an optimal object code with an optimal processing configuration. The object of the present invention is to provide a system for fixing registers so that object code can be generated quickly and appropriately.

(Means for Solving the Problems) The register fixing method according to the present invention includes a save target common operation result detection means, a save position determination means, a temporary save code generation means, a common operation result storage register save determination means, The system is equipped with temporary save code processing means and is configured to be able to generate object code for the compiler.

The save target common operation result detection means detects a common save referenced beyond the execution branch point in the program among the common TSs as registers that temporarily store the results of the common operations started by the optimization means. This is for detecting a target TS.

The evacuation position determination means is for determining an optimal position in a program that generates an object code for evacuation of the evacuation target TS activated by the evacuation target common operation result detection means into the main memory.

The temporary evacuation code generation means is for generating a temporary evacuation code for the evacuation target TS activated by the evacuation position determining means at the position determined by the evacuation position determining means.

The common operation result storage register save judgment means is for judging whether or not to save the save target TS activated by the register allocation means into the main memory, and to generate temporary save judgment information including the judgment result. be.

The temporary save code processing means is activated by the object code editing means and uses the temporary save judgment information generated by the common operation result storage register save judgment means to convert the temporary save code generated by the save position determining means into an object code. This is for executing processing regarding whether to output or not.

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

FIG. 1 is a block diagram showing an embodiment of the register fixing method according to the present invention.

In FIG. 1, the present invention includes a save target common calculation result detection means 1, a save position determining means 2, and a temporary save code generating means 3.
, common operation result storage register save determination means 4, and temporary save code processing means 5.

Normally, the compiler's object code generation process is
In order to generate an optimal object code by the optimization means, processing at the intermediate code stage such as summarizing common operations is performed, the code generation means generates an object code string from the intermediate code, and the register allocation means generates a register. The object code unit is edited by the object code editing means.

The saving target common operation result detection means 1 is activated by the optimization means every time a common TS is detected, and investigates whether or not the common TS notified from the optimization means is referenced over a wide area. do. After reading, the saving target common operation result detecting means 1 detects whether or not the flow of the program execution order is referenced beyond the control statement. If the above is the case, the evacuation position determining means 2 is activated with this common TS as the evacuation target TS, and the activation is notified.

The evacuation position determination means 2 is activated by the evacuation target common calculation result detection means 1. The evacuation target TS notified by the evacuation position determining means 2 is saved inside the main memory, but the most appropriate position within the program for generating the object code for evacuation is determined by the evacuation position determining means 2. Ru.

Therefore, the evacuation position determining means 2 uses the temporary evacuation code generating means 3.
is activated to notify the evacuation target TS and the evacuation position determined above.

The temporary evacuation code generation means 3 is activated by the evacuation position determination means 2. The evacuation target TS notified from the temporary evacuation code generation means 3 is saved in the main memory, but the temporary evacuation code indicating the object code for evacuation is sent from the temporary evacuation code generation means 3 as shown in FIG. It is generated at the notified evacuation position and is notified to the optimization means.

The common operation result storage register save determination means 4 is activated by the register allocation means, is notified of the temporary save code generated by the temporary save code generation means 3 and the use status of the register, and determines the use of the register corresponding to the temporary save code. Investigate the condition. When the register is used for another purpose, the temporary evacuation determination information 6 indicates that an actual evacuation object code will be generated for the corresponding temporary evacuation hood. On the other hand, when the register is not used for other purposes, the temporary save determination information 6 indicates that the corresponding temporary save code is invalid. FIG. 3 is an explanatory diagram showing the above operation.

The temporary save code processing means 5 is activated by the object code editing means. When the temporary evacuation code processing means 5 is notified of the temporary evacuation code generated by the temporary evacuation code generating means 3, the temporary evacuation code processing means 5 stores the temporary evacuation code and the corresponding temporary evacuation determination information 6.
Based on the above display, the object code is generated by processing whether to invalidate the temporary save code or generate the temporary save code and object code for saving the corresponding register to the main memory. Notify the editing means to that effect.

Through the above processing, it is possible to generate an optimal object code for saving a register that stores the result of a common operation to the main memory without impairing the processing speed.

(Effects of the Invention) As explained above, the present invention makes it possible to generate an object code for saving a register storing the result of a common operation to main memory as an optimal object code using an optimal processing configuration. In order to generate efficient object code, the result of a common operation is stored in a specific register and an object food that references that register is generated. This has the effect of being able to generate optimal object code that uses the code efficiently.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of a register fixing method according to the present invention. FIG. 2 is an explanatory diagram showing an example of a temporary save code generation position. FIG. 3 is an explanatory diagram showing the contents of temporary evacuation determination information. FIG. 4 is an explanatory diagram showing an example of common operations. FIG. 5 is an explanatory diagram showing an example of the save location of a register that stores the result of a common operation. FIG. 6 is an explanatory diagram showing an example of the stack method. FIG. 7 is an explanatory diagram showing an example of the evacuation priority method. 1...Evacuation target common operation result detection means 2...Evacuation position determination means 3...Temporary evacuation code generation means 4...Common operation result storage register Evacuation determination means 5...Temporary evacuation code processing means 6 ...Temporary evacuation determination information patent applicant NEC Co., Ltd. agent Patent attorney Hisashi Inoro 〉 Age 6

Claims (1)

[Claims] Among the common TSs that are activated by the optimization means and serve as registers that temporarily store the results of common operations, common save target Ts that are referenced beyond execution branch points in the program.
save target common operation result detection means for detecting S;
evacuation position determining means for determining an optimal position among a program for generating an object code for evacuation of the evacuation target TS into main memory, which is activated by the evacuation target common operation result detection means; and the evacuation position temporary evacuation code generation means for generating a temporary evacuation code for the evacuation target TS activated by the determination means to the position determined by the evacuation position determination means; and temporary evacuation code generation means for generating the temporary evacuation code for the evacuation target TS activated by the register allocation means a common operation result storage register save determination means for determining whether or not to save into the main memory and generating temporary save determination information including the determination result; Temporary saving for executing processing regarding whether or not to output the temporary saving code generated by the saving position determining means as an object code, based on the temporary saving judgment information generated by the saving judgment means. A register fixing method comprising a code processing means and configured to be able to generate object code for a compiler.