JPH0962512A - Program transformation device and method having description language transformation function from low-class language to high-class language - Google Patents

Abstract

PROBLEM TO BE SOLVED: To transform register preserving/recovering processing, which is contained in the respective procedure of low-class language program, into effective descriptions. SOLUTION: An assembly language program 11 is read into a description language transforming processor 20 and analyzed at a program analytic part 21, and a first type register to dispatch the program at the time of calling in each procedure and a second type register to reflect a master procedure with its value in the case of returning from each procedure are decided. when generating a high-class language program 12, a description language transforming part 22 expresses the respective respective registers in each procedure in local parameters for each procedure, describes the first type register in that procedure as the register to dispatch the program at the time of calling in that procedure and describes the second type register in that procedure as the register to reflect the master procedure with its value in the case of returning from that procedure in place of register preserving/recovering processing.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention is suitable for converting and generating a program (high-level language program) written in a high-level language from a program written in a low-level language represented by an assembly language (low-level language program). The present invention relates to a program conversion device and method having a description language conversion function from a low level language to a high level language.

[0002]

2. Description of the Related Art Conventionally, when converting a description language from a low-level language typified by assembly language to a high-level language typified by C language or FORTRAN, each procedure of a program (low-level language program) written in a low-level language is Regarding the register saving / restoring processing included, language conversion was performed faithfully to the description of the program.

FIG. 8 shows an assembly language program 81 including a register saving / restoring process to a high-level language (here, C
Program written in (language) (high-level language program)
An example of conversion to 82 is shown.

In the example of FIG. 8, the register save / restore processing (SAVE) included in the assembly language program 81 is performed.
/ RESTORE) target register is R2
To R15, and the 14 registers R2 to R15.
The register saving / restoring process for R15 is directly converted to the description in the high-level language (C language).

That is, a high-level language (C language) program 82
In the above, according to the global variable definition statement 821, the above 1
Global variables R1 to R15 that can be seen from each procedure (which is a name indicating an area on the memory) of the five registers
(The R1 to R15 are R in the assembly language program.
1 to R15 have different meanings), and the assignment statement 822 expresses the global variables R1 to R15 as local variables r1 to r15 inside the procedure (local variable r1).
.. to r15), the register saving process 811 for the 15 registers in the assembly language program 81 is converted into the C language description.

Further, by using the assignment statement 823, the local variables r1 to r15 are expressed by the global variables R1 to R15 (substitution to the global variables R1 to R15), thereby targeting 15 registers in the assembly language program 81. The register recovery process 812 is converted into a C language description.

[0007]

As described above, conventionally, when converting a description language from a low level language to a high level language,
For register saving / restoring processing included in each procedure of a low-level language program, it is common to perform language conversion faithfully to the description of the program.

For this reason, even in the high-level language program to be converted / generated, the register that is not rewritten in the procedure is also saved / restored, which has a problem of affecting the performance.

Further, since the register is represented by a global variable, the access to the register is converted into the access to the memory, and there is a problem that the performance is deteriorated. The present invention has been made in consideration of the above circumstances, and its purpose is to
When a high-level language program is generated by converting a description language from a low-level language to a high-level language, the register save / restore processing included in each procedure of the low-level language program can be converted into a lean description, It is an object of the present invention to provide a program conversion device and method capable of efficiently executing save / restore processing in a high-level language.

[0010]

The present invention provides a register,
The feature is that the register is not visible to other procedures by representing it as a local variable that can be seen only inside the procedure, not as a global variable that can be seen commonly in each procedure. And

By doing this, the problem that the access to the register is converted into the access to the memory can be solved, and the register represented by the local variable cannot be seen from other procedures, so that the register saving / restoring is performed. Even if no processing is performed, it does not have any influence on other procedures. For this reason, even registers that are not rewritten in the procedure are not subject to the save / restore processing.

However, when a register is represented by a local variable, it cannot be seen from other procedures as described above, and therefore it is possible for a register that needs to exchange a value with another procedure. A description is required.

Therefore, in the present invention, a low-level language program is analyzed, and for each procedure, a register referred to by the procedure and a procedure called directly or indirectly from the procedure (that is, a procedure following a child procedure) are referenced. Registers that are registered and that do not match the definition register that is rewritten by the procedure before it is directly or indirectly called by the procedure should be passed when the procedure is called (when the procedure is called from outside). Of the first type register (passed), and the definition register that is rewritten by the procedure and the definition register that is rewritten by the procedure that is called directly or indirectly from the procedure. When returning from a non-target register, the value is returned to the parent procedure when returning from the procedure. When determining as a second type of register to be processed and converting a low-level language program into a high-level language description to generate a high-level language program, instead of register save / restore processing for each procedure, the above determination is made. The register of the first type in the corresponding procedure described above is described as a register to be passed when the procedure is called, and the register of the second type in the determined corresponding procedure is returned when returning from the procedure. It is characterized in that it is described as a register whose value should be reflected in the parent procedure.

Here, the register saving / restoring processing included in each procedure of the low-level language program is analyzed (by the register saving / restoring analysis means) to recognize the register to be saved / restored. , The register definition / reference situation in each procedure of the low-level language program is analyzed (by the register definition / reference analysis means), and the call relationship between the procedures of the low-level language program is analyzed (by the procedure call relationship analysis means). Then, it becomes possible to efficiently determine the first type register and the second type register by using these analysis results (of the analysis means).

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the overall configuration of a program conversion device according to an embodiment of the present invention.

In the figure, 10 is an external storage device for storing various programs and the like. The external storage device 10 stores a program (assembly language program) 11 described in a low-level language, for example, an assembly language, which is a target of the description language conversion. The external storage device 10 also converts a description language targeted for the assembly language program 11, for example, a description language conversion from the assembly language to the high-level C language to convert and generate a high-level language (C A language program 12 is also stored.

Reference numeral 20 denotes a description language conversion processing device which reads the assembly language program 11 from the external storage device 10 and converts the assembly language into a high level language (for example, C language) to generate the high level language program 12. .

The description language conversion processing device 20 is realized by using a CPU, which is the center of a computer, and a memory for storing software (programs) for the description language conversion process. Each functional element of the analysis unit 21 and the description language conversion unit 22 is provided.

The program analysis unit 21 analyzes the assembly language program 11 and assigns a value to a register (first type register) that is passed from the outside when each procedure is called, and a value to the parent procedure when returning from each procedure. The register saving / recovery analyzing unit 211 is for determining the register (the second type register) to be reflected.
The register definition / reference analysis unit 212, the procedure call relation analysis unit 213, and the register determination unit 214 are functionally configured.

The register saving / restoring analysis unit 211 saves / registers registers included in each procedure of the assembly language program 11 read by the description language conversion processing device 20.
It has a function of analyzing a recovery process and recognizing a target register.

The register definition / reference analysis unit 212 has a function of analyzing the register definition / reference status in each procedure of the assembly language program 11 read by the description language conversion processing device 20.

The procedure call relation analysis unit 213 has a function of analyzing the call relation between procedures of the assembly language program 11. The register determination unit 214, based on the analysis results of the register storage / recovery analysis unit 211, the register definition / reference analysis unit 212, and the procedure call relation analysis unit 213, registers of the first type (external when calling each procedure). From the register) and the second
Type registers (registers whose values should be reflected in the parent procedure when returning from each procedure) are determined, and also registers used only inside the procedure (third type registers) are determined.

The description language conversion unit 22 includes a register determination unit 2
Based on the determination result of 14 and the assembly language program 11 read by the description language conversion processing device 20, it has a function of performing a description language conversion from an assembly language to a high-level language (here, C language).

Next, the operation of the configuration of FIG. 1 will be described with reference to the flow charts of FIGS. 4 to 7 by taking the case where the assembly language program 11 is as shown in FIG. 2A as an example. Note that the assembly language program 11 shown in FIG. 2A has the same contents as the assembly language program 81 (see FIG. 8) described in the "Prior Art" section.

First, the description language conversion processing device 20 reads the assembly language program 11 stored in the external storage device 10 (step S1). Then, the register saving / restoring analysis unit 211 in the description language conversion processing device 20 is activated by a control unit (not shown). The register saving / restoring analysis unit 211 stores which register (register group) is saved and restored in each procedure of the assembly language program 11 read from the external storage device 10, that is, register saving / restoring processing of each procedure. The target register (register group) is recognized (step S2). The recognition of the register saving / restoring processing is performed by checking the SAVE instruction and the RESTORE instruction for each procedure, and the recognition result is stored in a memory (not shown).

Assembly language program 1 of FIG. 2 (a)
In the example of No. 1, the registers R2 to R2 in the procedure PROC1.
It is recognized that R15 is subject to register save / restore processing.

Next, the register definition / reference analysis unit 212 is activated. The register definition / reference analysis unit 212 includes a register explicitly defined (rewritten) by each procedure of the assembly language program 11 read from the external storage device 10, a register referred to, and a position thereof ( A register definition / reference situation analysis process for recognizing the (order) is performed (step S3). This analysis process is performed by an instruction (see FIG. 2) involving register definition / reference for each procedure.
In the example of the assembly language program 11 in (a), this is performed by checking the load (L) instruction, and the result of the register definition / reference situation analysis is stored in the memory.

Assembly language program 1 of FIG. 2 (a)
In the example of No. 1, in the procedure PROC1, a defined (rewritten) register (definition register)
Is recognized by the registers R0 and R10, and the referenced register (reference register) is the register R3. In the procedure PROC2, it is recognized that the definition register is the register R1 and the reference register is the register R10. .

Next, the procedure call relation analysis unit 213 is activated. The procedure call relation analysis unit 213 analyzes the call relation between procedures in the assembly language program 11 read from the external storage device 10 (step S4). The location of the called procedure is also recognized here. The analysis result of the call relationship between the procedures is stored in the memory.

Assembly language program 1 of FIG. 2 (a)
In the first example, it is analyzed that the procedure PROC1 is called from the procedure PROC1. The activation order of the register saving / restoring analysis unit 211, the register definition / reference analysis unit 212, and the procedure call relation analysis unit 213 described above is not important and any order may be used.
Further, it may operate in parallel. Also,
In order to efficiently perform the analysis processing in each of the analysis units 211 to 213, the lexical words of the assembly language program 11 are analyzed in advance, the data structure in the assembly language of the program 11 is recognized, and the result is stored in the memory. Aside
The analysis result may be referred to by each of the analysis units 211 to 213. This lexical analysis result is described in the description language conversion unit 2
Since it can be referred to from 2, the waste of repeating the same processing by each unit can be omitted.

Now, the register saving / restoring analysis unit 211,
Analysis operations of the register definition / reference analysis unit 212 and the procedure call relation analysis unit 213 (steps S2, S3, S
When 4) ends, the register determination unit 214 is activated. The register determination unit 214 includes the analysis units 211 to 213 stored in the memory (steps S2 to S4).
)) Based on the analysis result, perform data flow analysis focusing on registers, and register registers that should be received from the outside when each procedure is called, and registers that should reflect the value to the parent procedure when returning from each procedure. A register determining process for determining is executed (step S5). The reason why the analysis result of the procedure call relation analysis unit 213 is necessary for the processing in the register determination unit 214 is the register definition /
Although the reference analysis unit 212 can recognize the register definition / reference of the procedure itself, in reality, another procedure (child procedure) may be called from that procedure, and there may be registers defined / referenced there. Is.

Details of the register determination processing in step S5 will be described with reference to the flowchart of FIG. First, the register determining unit 214 is configured to register the register definition / reference analysis unit 21.
2 based on the definition register and reference register in each procedure recognized in 2 and the target register of the save / recovery process in each procedure recognized by the register save / recovery analysis unit 211. A list (definition register list) of definition registers that are not subject to recovery (that is, definition registers whose values should be reflected in the parent procedure), save /
A list of definition registers to be restored (that is, definition registers used only inside the procedure) (internal definition register list) and a list of reference registers (reference register list) are generated (step S11). Each of these lists is stored in memory.

Next, the register deciding unit 214 excludes the registers in the definition register list in each procedure at that point in time even in the parent procedure except the registers in the internal definition register list in the parent procedure. As can be seen, it is added to the definition register list in the parent procedure (step S12).

Next, the register determining unit 214 excludes the registers in the reference register list of each procedure at that point in time, except for the registers defined in the parent procedure before the procedure is called. It is added to the reference register list in the parent procedure so that it can be seen inside (step S13). Whether or not the register in the reference register list is defined by the parent procedure before the corresponding procedure is called is determined by the register definition / reference analysis unit 212.
It can be determined from the relationship between the register position included in the reference situation analysis result and the position where the child procedure is called.

The register determining unit 214 repeats the above steps S12 and S13 until there is no change in the definition register list and the reference register list in all procedures before and after the execution of the steps S12 and S13 (step S14). That is, the register determination unit 214 repeats steps S12 and S13 as long as the contents of the definition register list or the reference register list in any procedure change before and after steps S12 and S13.

Then, when the definition register list and the reference register list in each procedure do not change before and after the execution of steps S12 and S13, the register determination unit 214 exits the loop of repetition of steps S12 and S13, and at that time point. The reference register list in each procedure is determined by the list of registers that should be passed when the procedure is called, and the definition register list in each procedure at that time is the list of registers whose values are to be reflected in the parent procedure. And decide (step S1
5). Further, the internally defined register list in each procedure at this point is determined as a list of registers used only inside the procedure.

With the above, the register determination processing of step S5 by the register determination unit 214 is completed. As a result, in the example of the assembly language program 11 of FIG. 2A, since the register saving / restoring target in the procedure PROC1 is the registers R2 to R15 in the definition register list of the procedure PROC1, the procedure PR is concerned.
Of the registers R0 and R10 defined in OC1, the register R0 that is not the target of saving / restoring and its procedure PR that is added from its child procedure PROC2 (because it is not the target of saving / restoring in procedure PROC1)
The register R1 defined by OC2 will be entered. On the other hand, only the register R1 is included in the definition register list of the procedure PROC2. This PROC
The contents of the definition register lists 1 and 2 are shown in FIG.
(B).

Next, only the register R10 to be saved / restored among the registers R0 and R10 defined in the procedure PROC1 is included in the internal definition register list of the procedure PROC1. On the other hand, nothing is entered in the internal definition register list of the procedure PROC2. The contents of the internally defined register list of PROC1 and PROC2 are shown in FIGS.

Next, only the register R3 referred to in the procedure PROC1 is entered in the reference register list of the procedure PROC1. The register R10 referenced in the procedure PROC2 is its parent procedure PROC1,
Since it is defined before that, the procedure PROC
It is not added to the reference register list of 1. On the other hand, in the reference register list of procedure PROC2, register R1
Only 0 enters. The contents of the reference register list of PROC1 and PROC2 are shown in FIGS.

When the register determination process (step S5) by the register determination unit 214 is completed, the description language conversion unit 22
Is started. The description language conversion unit 22 uses the external storage device 1.
Based on the assembly language program read from 0 and the register determination result in step S5, description language conversion processing for converting the description language from assembly language to C language (high-level language) is performed (step S6).

Details of the description language conversion processing in step S6 will be described with reference to the flowcharts of FIGS. 6 and 7. First, the description language conversion unit 22 detects the description language conversion target portion (label or instruction) in order from the beginning of the assembly language program 11 (the data structure recognized as a result of the lexical analysis for the assembly language program 11) which is the conversion target (step). S21).

If the description language conversion target portion can be detected (step S22), the description language conversion unit 22 determines that the description language conversion target portion is a label (in the example of FIG. 2,
It is determined whether it is PROC1 or PROC2) or an instruction (step S23).

When the detected description language conversion target portion is a label, the description language conversion unit 22 converts the label into a function definition statement described in a high-level language (C language) and gives it as an argument from the outside. Information (local variable representing each register in the reference register list in the procedure corresponding to the label), and the type (name) and address of the structure of information to be passed to the parent procedure are set (step S26).

Subsequently, the description language conversion unit 22 generates a definition statement of a local variable used inside the corresponding procedure (step S27). In this local variable definition statement, a local variable representing each register in the definition register list and the internal definition register list obtained by the register determining unit 214 is defined.

However, when the detected label is not the first label, that is, when the start of a procedure other than the first procedure is detected, in other words, when a procedure break is detected, the description language conversion unit 22 Is the above step S
Prior to step 26, a process is performed to generate an assignment statement (the last statement of the preceding procedure) that stores the value to be reflected in the parent procedure in the structure so that the value can be reflected in the parent procedure from the preceding procedure ( Step S25).

As a result of the above, the label PRO in FIG.
If C1 is detected, a function definition statement 121 and a local variable definition statement 122 in a high-level language (C language) as shown in FIG. 2B are converted / generated.

In the function definition statement 121, as an argument, an integer type (int) local variable r3 representing the register R3 in the reference register list of PROC1 shown in FIG. 3 (e).
And the type of the structure of information passed to the parent procedure, "struc
“t ret1” and the address “* ret” are set in the local variable definition statement 122.
Definition register list of PROC1 shown in (a) and FIG.
An integer type (int) representing each register R0, R1, R10 in the internally defined register list of PROC1 shown in (c).
Local variables r0, r1, r10 are defined.

Similarly, the label PROC2 in FIG.
2 is detected, the function definition statement 123 and the local variable definition statement 124 in the high-level language (C language) as shown in FIG. 2B are converted / generated.

In the function definition statement 123, as an argument, an integer type (int) local variable r representing the register R10 in the reference register list of PROC2 shown in FIG. 3 (f).
10 and the type of the structure of information passed to the parent procedure, "str
ct ret2 ”and the address“ * ret ”are set in the local variable definition statement 124 shown in FIG.
An integer type (int) local variable r1 representing the register R1 in the definition register list of PROC2 shown in (b) is defined.

Prior to the generation of the function definition statement 123 and the local variable definition statement 124, two assignment statements 125 as shown in FIG. 2B are generated. In this assignment statement 125, local variables r0 and r1 representing the registers R1 and R2 in the definition register list of PROC1 shown in FIG.
Is assigned as r0 and r1 in the area indicated by "ret" of the structure to be passed to the parent procedure.

The description language conversion unit 22 executes the step S26,
When S27 is executed, the process returns to step S21, and the process for detecting the next description language conversion target part from the assembly language program 11 is performed.

Next, when the detected description language conversion target portion is not a label but an instruction, the description language conversion unit 22
Is the register save / restore instruction (SAVE / R
It is determined whether it is an ESTORE command), a procedure call command (CALL command), or another command (steps S28 and S29).

If the detected description language conversion target portion is a register save (SAVE) or restore (RESTORE) command, the description language conversion unit 22 returns to step S21 without doing anything and returns to the next description language conversion target. Perform the process of detecting the part.

In the description language conversion unit 22, the detected description language conversion target portion is a register save / restore instruction (SAVE
If the command is neither a / RESTORE command) nor a procedure call command (CALL command), the command is converted into a high-level language (C language) description as it is (step S30), and the process returns to step S21.

As a result, the load instruction L in FIG.
If (R0,1) and L (R10, R3) are detected, a high-level language (C language) as shown in FIG. 2B.
Are converted into "r0 = 1" and "r10 = r3".

Similarly, the load instruction L (R) in FIG.
1, R10) is detected, a high-level language (C language) assignment statement “r1 = r10 as shown in FIG. 2B.
Is converted to

When the detected description language conversion target portion is a procedure call instruction (CALL instruction), the description language conversion unit 22 converts the instruction into a function call statement described in a high-level language (C language). Then, a local variable representing each register in the reference register list of the child procedure and the address of the structure of information received from the child procedure are set as arguments (step S31).

Subsequently, the description language conversion unit 22 generates an assignment statement for receiving information from the child procedure through the structure (step S32), and returns to step S21. This causes the procedure call instruction (CAL) to call the procedure PROC2 included in the procedure PROC1 in FIG.
If the L instruction) is detected, the function call statement 126 and the assignment statement 127 in the high-level language (C language) as shown in FIG. 2B are converted / generated.

In the function call statement 126, as an argument, an integer type (int) local variable r10 representing the register R10 in the reference register list of the PROC2 shown in FIG. 3E and a structure of information received from the child procedure. The address "&ret2" of (structure of type "struct ret2") is set. On the other hand, the assignment statement 127 indicates that the content of the address r1 of the structure indicated by "ret2" is used as the local variable r1 in the procedure PROC1.

Further, if the description language conversion unit 22 cannot detect the description language conversion target portion (step S2).
2) As an end of the assembly language program 11, an assignment statement for storing the value to be reflected in the parent procedure from the procedure currently being processed in the structure is generated (step S3).
3) The series of description language conversion processing (step S6) is ended.

By this step S33, in the example of the assembly language program 11 of FIG. 2A, the assignment statement 128 as shown in FIG. 2B is generated. This assignment statement 12
8, the local variable r1 representing the register R1 in the definition register list of PROC2 shown in FIG. 3B is r1 in the area indicated by "ret" of the structure passed to the parent procedure.
It is shown to substitute as.

When the description language conversion section 22 completes the series of description language conversion processing (step S6), the description language conversion processing result of the high-level language program 12 as shown in FIG. 2B is obtained. The data is output to the external storage device 10 (step S7). As a result, the processing in the description language conversion processing device 20 for analyzing the assembly language program 11 and converting it into a description in a high-level language (C language) and generating the high-level language (C language) program 12 is completed.

As described above, in this embodiment, when the assembly language program 11 is converted into the description of the high-level language (C language) to generate the high-level language (C language) program 12, the program 11 is analyzed. By analyzing in the unit 21, each procedure (PROC1, PROC
For each 2), the list of registers that should be passed when the procedure is called (reference register list), the list of registers that should reflect the value to the parent procedure when returning from the procedure (definition register list), and inside the procedure A list of registers to be used only (internally defined register list) is obtained and stored in a memory, and based on the list in the memory, in the description language conversion unit 22, for each procedure,
The registers in each corresponding list are represented by local variables.

As a result, the access to the register is not converted into the access to the memory, and the performance is not deteriorated. Moreover, since the register represented by the local variable cannot be seen from other procedures, it does not have any influence on other procedures without register saving / restoring processing.

Further, in the present embodiment, instead of register saving / restoring processing for each procedure, the register in the corresponding reference register rest is treated as a register to be passed at the time of calling of the procedure, and it corresponds. Since the register in the definition register is treated as a register whose value should be reflected in the parent procedure when returning from the procedure, and the corresponding description is made in the description language conversion unit 22, the register is represented by a local variable. However, for registers that need to exchange values with other procedures, they can be exchanged.

The case where the assembly language is converted into the C language description has been described above.
It is also applicable when converting to a high-level language other than C language such as RAN.

[0067]

As described in detail above, according to the present invention, when a high-level language program is generated by converting a description language from a low-level language to a high-level language, a register can be seen only inside a procedure. Expressed by local variables, instead of register save / restore processing for each procedure, operation to pass the register required when calling the procedure and reflect the register value to the parent procedure required when returning from the procedure Since, the register saving / restoring processing included in each procedure of the low-level language program can be converted into a description without waste,
The recovery process can be executed efficiently in a high-level language.

[Brief description of drawings]

FIG. 1 is a block diagram showing an overall configuration of a program conversion device according to an embodiment of the present invention.

FIG. 2 is an assembly language program 1 in the same embodiment.
1 is a diagram showing the example 1 and a high-level language program 12 generated by performing a description language conversion from an assembly language to a high-level language (C language) for the assembly language program 11 as a target.

3 shows an example of contents of a definition register list, an internal definition register list, and a reference register list for each procedure determined by a program analysis unit 21 (internal register determination unit 214) in FIG. The figure shown about the case where the language program 11 is made into object.

FIG. 4 is a flowchart for explaining the flow of overall processing according to the embodiment.

5 is a flowchart for explaining in detail a processing flow of step S5 (register determination processing) in the flowchart of FIG.

FIG. 6 is a diagram showing a part of a flowchart for explaining in detail the processing flow of step S6 (description language conversion processing) in the flowchart of FIG. 4;

7 is a diagram showing the rest of the flowchart for explaining in detail the processing flow of step S6 (description language conversion processing) in the flowchart of FIG.

FIG. 8 is a diagram showing a high-level language program 82 converted and generated from an assembly language program 81 by a conventional description language conversion process, in comparison with the assembly language program 81.

[Explanation of symbols]

10 ... External storage device, 11 ... Assembly language program (lower language program), 12 ... High-level language program, 20 ... Description language conversion processing device, 21 ... Program analysis unit, 22 ... Description language conversion unit, 211 ... Register save / restore Analysis unit, 212 ... Register definition / reference analysis unit, 213 ... Procedure call relation analysis unit, 214 ... Register determination unit.

Claims (3)

[Claims] 1. A program conversion device for converting a low-level language program described in a low-level language into a high-level language description to generate a high-level language program, analyzing the low-level language program, and for each procedure, its procedure. , And the registers that are referenced in the procedure that is called directly or indirectly from the procedure, and are different from the definition registers that are rewritten in the procedure before being called directly or indirectly from the procedure, It is determined as the first type of register that should be passed when each procedure is called, and the definition register that is rewritten by that procedure and the definition register that is rewritten by the procedure that is called directly or indirectly from that procedure Registers that are not subject to save / restore processing While determining from the register of the second type that the value should be reflected in the parent procedure when returning from the procedure, the register to be saved / restored in that procedure among the definition registers that are rewritten in that procedure Program analysis means for determining as a third type of register to be used only, and a high-level language program by converting the low-level language program into a high-level language description based on the register determination result of the low-level language program and the program analysis means Is a description language conversion means for generating each of the registers of the first to third types determined by the program analysis means for each procedure by a local variable, instead of the register saving / restoring processing, The register of the first type determined for each procedure should be passed when the procedure is called. And a description language conversion means for describing the second type of register determined for each procedure as a register whose value should be reflected in the parent procedure when returning from the procedure. Characteristic program conversion device. 2. The program analysis means analyzes register saving / restoring processing included in each procedure of the low-level language program and recognizes a register to be saved / restored for each procedure. / Recovery analysis means and register definition in each procedure of the low-level language program /
A register definition / reference analysis means for analyzing a reference situation, a procedure call relationship analysis means for analyzing a call relationship between procedures of the low-level language program, the register save / recovery analysis means, the register definition /
Based on the analysis results of the reference analysis means and the procedure call relationship analysis means, the register of the first type to be passed when calling each procedure, and the value to be reflected in the parent procedure when returning from each procedure, Register deciding means for deciding the register of the second type which is not subject to save / restore in the procedure and the register of the third type which is subject to save / restore in the procedure and is used only in the procedure; The program conversion device according to claim 1, further comprising: 3. A program conversion method for converting a low-level language program written in a low-level language into a high-level language description to generate a high-level language program, wherein the low-level language program is analyzed, and the procedure is executed for each procedure. , And the registers that are referenced in the procedure that is called directly or indirectly from the procedure, and are different from the definition registers that are rewritten in the procedure before being called directly or indirectly from the procedure, It is determined as the first type of register that should be passed when each procedure is called, and the definition register that is rewritten by that procedure and the definition register that is rewritten by the procedure that is called directly or indirectly from that procedure Registers that are not subject to save / restore processing While determining from the register of the second type that the value should be reflected in the parent procedure when returning from the procedure, the register to be saved / restored in that procedure among the definition registers that are rewritten in that procedure It is determined as a third type of register to be used only, and when converting the low-level language program to a high-level language description to generate a high-level language program, for each procedure, Each of the first to third types of registers is represented by a local variable, and instead of the register saving / restoring process, the first type of register in the determined corresponding procedure is used as a register to be passed when the procedure is called. In addition to the description, the value of the second type register in the determined corresponding procedure is returned to the parent procedure when returning from the procedure. Program conversion method characterized by described as should do register.