JPH0588909A - System for optimizing object by assignment of argument for internal procedure call to register - Google Patents

Abstract

PURPOSE:To provide the object optimizing method for argument reference and setting of internal procedures with respect to an object generated by a compiler. CONSTITUTION:When compiling a procedure call instruction, a call procedure discrimination processing 1 discriminates whether procedures are internal procedures or external procedures. A main procedure breakable register search processing 2 obtains breakable registers in the case of internal procedures. A breakable register search processing 3 obtains breakable registers. A register assignment determination processing 4 discriminates whether an argument can be assigned to a register or not. An argument-register assignment processing 5 substitutes variables in internal procedures with registers based on a table and deletes unnecessary transfer instructions. Consequently, registers are effectively used at the time of argument transfer, reference, and setting of internal procedures to optimize machine language instructions.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optimization method for generating an optimum object program when compiling a source program having internal procedures.

[0002]

2. Description of the Related Art Conventionally, a procedure call argument has a temporary area (hereinafter called an argument area) for a caller (hereinafter referred to as a main procedure) to communicate with an external procedure or an internal procedure. I was calling it) and handing it over.

[0003]

In the conventional method, since the argument is always assigned to the argument area, the instruction for assigning to the argument area at the time of calling the main procedure and the argument area in the called external procedure or internal procedure. Optimal object is not created because variables are fetched from and write commands are created.

An object of the present invention is to provide optimization of machine language instructions and an optimization method for reducing the number of machine language instructions.

[0005]

In order to achieve the above object, in an optimization method by allocating arguments of internal procedure calls according to the present invention to registers, a source program is read and an optimum object program is output. Whether a procedure that is trying to process an instruction that calls a certain set of processing (procedure) exists in the compilation (internal procedure) or does not exist in the compilation unit (external procedure). And a register that is not used in the process of processing a procedure call when the procedure call is an internal procedure (destructible register)
And in the process of processing internal procedures,
A means for obtaining a destructible register, a means for determining whether or not the argument to be passed to the internal procedure can be assigned to the register, and a register showing the relationship between the register and the argument when the argument to be passed to the internal procedure is assigned to the register. A variable correspondence table and means for replacing an argument in an internal procedure with a register and deleting an unnecessary register-variable transfer instruction based on the register-variable correspondence table.

Further, when there is the destructible register, it is registered in the internal procedure destructible register number of the register-variable correspondence table.

Further, a common destructible register is obtained from the destructible register numbers, and if the destructible register number is not registered, the processing is terminated, and if it is registered, the argument in the internal procedure is replaced with the register. , Unnecessary register-variable transfer instructions are deleted.

[0008]

In the process of compiling an instruction for calling a procedure, it is determined whether the procedure to be processed is an internal procedure or an external procedure. If the procedure call is an internal procedure, a destructible register is obtained by the internal call. Furthermore, it is determined whether the argument to be passed to the internal procedure can be assigned to a register, the variable in the internal procedure is replaced with the register based on the register-variable correspondence table, and an unnecessary register-variable transfer instruction is executed. To reduce.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention.

Referring to FIG. 1, in this embodiment, a calling procedure determination process 1 and a main procedure destructible register search process 2 are performed.
, Internal procedure destructible register search processing 3, register allocation availability determination processing 4, and argument-register allocation processing 5.

In the optimization method of allocating an argument to a register according to the present invention and using the register for communication with an internal procedure, the calling procedure judgment processing 1 is going to process it in the process of compiling an instruction to call the procedure. Main procedure destructible register search processing by judging whether the procedure is an internal procedure (procedure to be processed exists in the compilation) or external procedure (procedure to be processed does not exist in the compilation unit) In 2, when the procedure call is an internal procedure, a destructible register (a register that is not used) is obtained in the process of processing the procedure call.

Further, in the internal procedure destructible register search process 3, in the process of processing the internal procedure, a destructible register is obtained, and the register allocation availability determination process 4
Then, it is determined whether the argument passed to the internal procedure can be assigned to the register.

Register-variable correspondence table (see FIG. 2)
Represents the relationship between the registers and variables when the arguments to be passed to the internal procedure are allocated to the registers. The argument-register allocation processing 5 registers the variables in the internal procedure based on the register-variable correspondence table. To remove unnecessary register-variable transfer instructions.

FIG. 2 is a diagram showing the structure of the register-variable correspondence table, which comprises internal destructible register numbers, calling procedure serial numbers, and destructible register numbers corresponding to the calling procedure serial numbers. There is.

FIG. 3 shows a flow chart of the processing of the embodiment.

The processing in this embodiment will be described below.

(Machine Language Input Processing S1) Machine Language Input Processing S
1 reads a machine language from the machine language file F1. The compiler inputs a source file here, parses it, converts it into an intermediate language, and outputs it to an intermediate language file. The machine language generation unit inputs the intermediate language file, creates a machine language, and then outputs the machine language file.

(Input end determination processing S2) In the input end determination processing S2, it is determined whether or not the input of the machine language is completed. If the input is not completed, the control is transferred to the machine language memory expansion processing S3. When the input of the machine language is completed, the control is transferred to the instruction pointer setting process S4.

(Machine Language Memory Expansion Processing S3) In the machine language memory expansion processing S3, the machine language read in the machine language input processing S1 is expanded in the memory and the control is transferred to the machine language input processing S1.

(Instruction Pointer Setting Process S4) In the instruction pointer setting process S4, the instruction pointer is set to the first machine language expanded in the memory, and then the control is transferred to the instruction end determination process S5.

(Calling procedure determination processing S5) The calling procedure determination processing S5 determines whether the instruction being processed is a procedure calling instruction, and if it is a calling procedure, further determines whether the calling procedure is an internal procedure. If it is an internal procedure, control is transferred to the main procedure destructible register search processing S6, and if it is not an internal procedure call, control is transferred to the internal procedure determination processing S7.

(Main procedure destructible register search process S
6) The main procedure destructible register search process S6 searches for a destructible register by executing the internal procedure call instruction,
If it is a destructible register, the calling sequence number and the destructible register number are registered in the register-variable correspondence table.

(Internal procedure determination processing S7) The internal procedure determination processing S7 determines whether or not the instruction being processed is the start of the internal procedure, and if it is the start of the internal procedure, the internal procedure destructible register search processing S8 is executed. Transfer control,
If it is not the start of the internal procedure, the control is shifted to the instruction pointer update processing S9.

(Internal procedure destructible register search process S
8) Internal procedure destructible register search processing S8 searches for a destructible register from the start of the internal procedure to the end of the internal procedure, and if there is a destructible register, the internal procedure destructible register number of the register-variable correspondence table is set. register.

(Instruction pointer update processing S9) In the instruction pointer update processing S9, the instruction pointer is advanced to the next machine language instruction, and the control is shifted to the instruction end determination S5.

(Instruction End Processing S10) Instruction End Processing S1
At 0, it is determined whether the instruction pointer has reached the end of the instruction expanded in the memory. If it is not the end of the instruction, control is transferred to the calling procedure determination processing S5, and if it is the end of the instruction, argument-register allocation is performed. Control is transferred to process S11.

(Argument-register allocation processing S11) In the argument-register allocation processing S11, a common destructible register number is obtained from the destructible register numbers corresponding to the respective calling sequence numbers in the register-variable correspondence table, and the destructible register numbers are registered. If not, the process is terminated, and if a destructible register is registered, the common destructible register of the obtained common destructive register number and internal procedure destructive register sequence number is obtained, and the common destructible register is available. If the register does not exist, the process ends. If there is a common destructible register, the register allocation availability determination process S12 is called to determine whether the requested register can be allocated to the argument. Replace the argument in the A register - Remove transfer instructions between variables.

(Argument-register allocation availability determination processing S
12) Argument-register allocation availability determination processing S12
It is determined whether the common register and the argument obtained in the argument-register allocation process S11 can be allocated.

[0030]

As described above, according to the present invention, when optimizing a machine language instruction, it is possible to optimize the machine language instruction by effectively using a register in the argument passing of the internal procedure and the reference and setting of the argument. And has the effect of reducing the number of machine language instructions.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a configuration diagram showing a register-variable table that is a component of the present invention.

FIG. 3 is a flowchart showing an argument-register allocation optimizing process of the present invention.

[Explanation of symbols]

 1 Call procedure determination processing 2 Main procedure destructible register search processing 3 Internal procedure destructible register search processing 4 Register allocation availability determination processing 5 Argument-register allocation processing

Claims (3)

[Claims] 1. A set of certain processes (procedure) in a compilation process for reading a source program and outputting an optimum object program.
Means to determine whether the procedure that is trying to process the instruction that calls is present in the compilation (internal procedure) or not in the compilation unit (external procedure), and the procedure call if the procedure call is an internal procedure Is it possible to allocate registers to the registers that are not used in the process of processing (destructible registers), means to find destructible registers in the process of processing internal procedures, and arguments passed to internal procedures? A register-variable correspondence table that represents the relationship between the registers and the arguments when the arguments to be passed to the internal procedure are assigned to registers, and the arguments in the internal procedure are registered based on the register-variable correspondence table. To remove unnecessary register-variable transfer instructions. Optimization method according to allocate an argument of internal procedure calls, characterized in that it comprises a means to register. 2. When there is the destructible register,
The optimization method by allocating an argument of an internal procedure call to a register according to claim 1, wherein this is registered in an internal procedure destructible register number of the register-variable correspondence table. 3. A common destructible register is obtained from the destructible register numbers, and if the destructible register number is not registered, the process is terminated, and if registered, the argument in the internal procedure is replaced with the register. , Unnecessary registers
An optimization method by allocating an argument of an internal procedure call to a register according to claim 1, wherein a transfer instruction between variables is deleted.