Multi-threaded fragment patching

• US 7,069,549 B2
• Filed: 05/16/2001
• Issued: 06/27/2006
• Est. Priority Date: 11/16/1998
• Status: Expired due to Term

• Current Assignee: RPX Corporation
• Original Assignee: Esmertec AG (Myriad Group AG)
• Inventors: Rautenbach, Keith, Wynn, Michael John, Sexton, Jeremy James, Kramskoy, Jeremy Paul, Guthrie, Philippa Joy, Dias, Blaise Abel Alec, Darnell, Stephen, Plummer, Wayne, Charnell, William Thomas, Thomas, Stephen Paul
• Primary Examiner(s): Nguyen-Ba, Antony
• Application Number:
  US09/858,578
• Publication Number:
  US 20020104077A1
• Time in Patent Office: 1,868 Days
• Field of Search: 717/148, 717168-178, 717162-167, 717/159, 717/136, 717/139, 717/141, 717/151, 717/152, 717/157, 717/158, 711/118, 711/153, 711/170, 711/213, 712/220, 712/226, 712/233, 712/234, 712/244
• US Class Current: 717/158
• CPC Class Codes: G06F 11/3612 by runtime analysis performance monitoring G06F11/3466
• CPC Class Codes: G06F 12/0269 Incremental or concurrent garbage collection, e.g. in real-time systems G06F12/0261 takes precedence
• CPC Class Codes: G06F 2209/481 Exception handling
• CPC Class Codes: G06F 8/4442 Reducing the number of cache misses; Data prefetching cache prefetching G06F12/0862
• CPC Class Codes: G06F 8/445 Exploiting fine grain parallelism, i.e. parallelism at instruction level run-time instruction scheduling G06F9/3836
• CPC Class Codes: G06F 9/4484 Executing subprograms
• CPC Class Codes: G06F 9/449 Object-oriented method invocation or resolution
• CPC Class Codes: G06F 9/4491 Optimising based on receiver type
• CPC Class Codes: G06F 9/455 Emulation; Interpretation; Software simulation, e.g. virtualisation or emulation of application or operating system execution engines
• CPC Class Codes: G06F 9/45516 Runtime code conversion or optimisation
• CPC Class Codes: G06F 9/4812 by interrupt, e.g. masked
• CPC Class Codes: Y10S 707/99932 Access augmentation or optimizing
• CPC Class Codes: Y10S 707/99953 Recoverability
• CPC Class Codes: Y10S 707/99956 File allocation

Abstract

A method and system multi-threaded fragment patching. The method provides a link in a self-modifying multi-threaded computer system between a first and a second piece of compiled code where the first piece of compiled code includes a control transfer instruction to the second piece of compiled code. The link is formed by inserting a patch from the first piece of compiled code to the second piece of compiled code. The patch may be a direct reference or a reference to an outlier.

Claims

1. A method of providing a link between pieces of compiled code in a self-modifying multi-threaded computer system having system memory and a system compiler for compiling a program during execution of a program, the method comprising the steps of:

(a) first determining whether a first piece of code includes a dominant path therethrough formed of a series of program instructions for execution one after another in sequence during execution of the dominant path;

(b) first determining whether the first piece of code includes a control transfer instruction therein;

(c) first compiling the first piece of code by the system compiler during execution of the program to provide a first piece of compiled code only if the first piece of code is determined to be a dominant path and the control transfer instruction is determined to be present in the first piece of code;

(d) second compiling a second piece of code by the system compiler during execution of the program to provide a second piece of compiled code; and

(e) creating a link between the first and second pieces of compiled code by changing the control transfer instruction within of the first piece of compiled code, whereby the link is disposed in the first piece of compiled code for linking the first piece of compiled code to the second piece of compiled code.

2. A method as claimed in claim 1, wherein creating a link between the first piece of compiled code and the second piece of compiled code includes making a reference to an outlier by changing the control transfer instruction within the first piece of compiled code.

3. A method as claimed in claim 1, further comprising recording information about the link in a buffer.

4. A method as claimed in claim 1, further comprising maintaining a hash table.

5. A method as claimed in claim 1, wherein creating a link between the first piece of compiled code and the second piece of compiled code by changing the control transfer instruction within the first piece of compiled code includes making a change to an instruction atomically.

6. A method as claimed in claim 1, further comprising removing the link when a predetermined condition occurs.

7. A method as claimed in claim 6, wherein the predetermined condition is that assumptions made during compilation are no longer valid.

8. A method as claimed in claim 6, wherein the predetermined condition is that a code buffer holding the second piece of compiled code is required for use elsewhere in the computer system.

9. A method as claimed in claim 6, wherein the predetermined condition is that the second piece of compiled code is no longer required by the computer system.

10. A method as claimed in claim 6, wherein removing the link includes identifying any links between the first and second pieces of compiled code.

11. A method as claimed in claim 6, further comprising redirecting any identified links to glue code.