Method and apparatus for loading native object code in data processing system

• US 6,295,638 B1
• Filed: 07/30/1998
• Issued: 09/25/2001
• Est. Priority Date: 07/30/1998
• Status: Expired due to Term

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Winters, Scott Lee, Brown, Michael Wayne, McIntyre, Joseph Herbert
• Primary Examiner(s): Powell, Mark R.
• Assistant Examiner(s): Booker, Kelvin
• Application Number:
  US09/126,283
• Time in Patent Office: 1,153 Days
• Field of Search: 717/1, 717/5, 717/7, 717/9
• US Class Current: 717/148
• CPC Class Codes: G06F 9/44557 Code layout in executable memory
• CPC Class Codes: G06F 9/45504 Abstract machines for programme code execution, e.g. Java virtual machine [JVM], interpreters, emulators

Abstract

A method and apparatus that provides a method for loading native code into the memory of a data processing system for use by a Java virtual machine. Native code is loaded for a method into the memory, wherein the memory is accessible by the Java virtual machine. An indicator is set to indicate to the Java virtual machine that native code is present for the method.

Claims

1. A process in a data processing system for loading native code, the process comprising:

loading native code for a method into memory for execution by a virtual machine that normally interprets code, wherein the native code is used by the data processing system; and

altering an indicator to indicate that native code is present for the method, wherein the indicator is located within a fixup table in the virtual machine.

2. The process of claim 1 further comprising:

creating an entry point for the native code in which the entry point is used to access the native code when the method is executed.

3. The process of claim 1, wherein the process is executed by a class loader.

4. The process of claim 1, wherein the native code is located in a class file.

5. The process of claim 1, wherein the native code is located on a server having a communications link to the data processing system.

6. The process of claim 1, wherein the virtual machine is a Java virtual machine.

7. A process for loading native code into a data processing system for use by a Java virtual machine, the process comprising data processing system implemented steps of:

loading bytecode for a method into a memory, wherein the memory is accessible by the Java virtual machine;

determining whether native code exists for the method;

loading the native code for the method into the memory in response to a determination that native code exists for the method and setting an indicator to indicate to the Java virtual machine that native code is present in memory for the method; and

interpreting the bytecode in response to no indicator indicating that native code is present in memory for the method.

8. The process of claim 7, wherein the indicator is located in a fixup table in the Java virtual machine.

9. The process of claim 7, wherein the loading step is performed by a loader class within the Java virtual machine.

10. The process of claim 7, wherein the loading step loads native code from a fully caffienated class file.

11. The process of claim 7, wherein the loading step loads native code from a server connected to the data processing system.

12. A data processing system comprising:

a virtual machine, wherein the virtual machine executes methods;

loading means for loading native code for a method into a memory, wherein the memory is accessible by the virtual machine;

setting means for setting an indicator to indicate to the virtual machine that native code is present in memory for the method; and

interpreting means for interpreting code to execute the method in response to no indicator indicating that native code is present for the method.

13. The data processing system claim 12, wherein the indictor is located in a fixup table in the virtual machine.

14. The data processing system of claim 12, wherein the loading means and the setting means are located in a loader class within the virtual machine.

15. The data processing system of claim 12, wherein the virtual machine is a Java virtual machine.

16. A Java virtual machine for use in a data processing system comprising:

a plurality of entry points into memory accessible by the Java virtual machine; and

a loader class, wherein the loader class loads native code, generated from a source other than from within the Java virtual machine, for execution by the data processing system and modifies an entry point within the plurality of entry points to provide an entry point for the native code.

17. The Java virtual machine of claim 16, wherein the plurality of entry points is located in a fixup table.

18. The Java virtual machine of claim 16, wherein the loader class loads native code from a fully caffienated class file.

19. The Java virtual machine of claim 16, wherein the loader class loads the native code from a server data processing system connected to the data processing system.

20. The Java virtual machine of claim 16 further comprising:

a just-in-time compiler, wherein the just-in-time compiler generates native code from bytecodes for a method and modifies an entry point within the plurality of entry points to provide an entry point to the native code generated from bytecodes and sets an indicator to indicate that the method has been processed by the just-in-time compiler,

wherein the class loader sets an indicator in a manner compatible with the manner used by the just-in-time compiler.

21. A computer program product in a computer readable medium for loading native code for a computer onto the computer, the computer program product comprising:

first instructions for loading native code for a method into memory, wherein the memory is accessible by a virtual machine that normally interprets code; and

second instructions for setting an indicator to indicate to the virtual machine that native code is present for the method, wherein the indicator is located within a fixup table in the virtual machine.

22. A computer program product in a computer readable medium for loading native code for a computer onto the computer, the computer program product comprising:

first instructions for loading native code for a method into memory, wherein the memory is accessible by a virtual machine that normally interprets code;

second instructions for setting an indicator to indicate to the virtual machine that native code is present for the method; and

third instructions for creating an entry point for the native code in which the entry point is used to access the native code when the method is executed.