COMPUTER SYSTEM

• US 20080016507A1
• Filed: 06/29/2007
• Published: 01/17/2008
• Est. Priority Date: 11/16/1998
• Status: Active Grant

• Current Assignee: RPX Corporation
• Original Assignee: Esmertec AG (Myriad Group AG)
• Inventors: Thomas, Stephen, Rautenbach, Keith, Sexton, Jeremy, Dias, Blaise, Darnell, Stephen, Wynn, Michael, Plummer, Wayne, Guthrie, Philippa, Charnell, William, Kramskoy, Jeremy
• Granted Patent: US 8,127,280 B2
• Time in Patent Office: Days
• US Class Current: 718/100
• 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 computer system which includes a plurality of threads and a garbage collector that traces memory objects and identifies memory objects according to a three-color abstraction. The computer system also includes two methods of deleting compiled code in a self-modifying multi-threaded computer system. The computer system also utilizes a method of handling links between fragments of code in a self-modifying multi-threaded computer system. The computer system also handles patches between two pieces of code.

Claims

1. A computer system comprising:

a plurality of threads;

a garbage collector that traces memory objects and identifies memory objects according to a three-color abstraction, the garbage collector identifying a memory object with a certain color if that memory object itself has been encountered by the garbage collector, but some of the objects to which the memory object refers have not yet been encountered; and

a packet manager accessible by the plurality of threads and the garbage collector, the packet manager operable to organize memory objects identified with the certain color into packets, provide services to obtain empty or partially full packets and obtain fill or partially full packets, and verify whether a packet of the certain color is being accessed by one of the plurality of threads of the garbage collector.

2. A computer system as claimed in claim 1, wherein the certain color is gray.

3. A computer system as claimed in claim 1, wherein each packet includes a plurality of slots.

4. A computer system as claimed in claim 3, wherein each packet includes one slot per reference to a memory object.

5. A computer system as claimed in claim 1, wherein each packet has a fixed size.

6. A method of deleting compiled code in a self-modifying multi-threaded computer system, the method comprising:

selecting a section of compiled code to be deleted;

identifying any patches in the section of compiled code;

redirecting any identified patches to other code; and

deleting the section of compiled code.

7. A method as claimed in claim 6, wherein the section of compiled code to be deleted has a range of addresses, the method further comprising:

examining a frame of a stack in the computer system;

identifying whether the frame contains a return address that is in the range of addresses of the section of compiled code to be deleted; and

altering the contents of the frame in the event that the frame contains a return address that is in the range of addresses of the section of compiled code to be deleted.

8. A method of deleting compiled code in a self-modifying multi-threaded computer system, the method comprising:

selecting a code buffer to delete, the code buffer having an address;

generating a hash of the address of the code buffer;

selecting a patch block;

identifying whether there is a patch into the code buffer to be deleted;

if a patch into the code buffer is identified, redirecting the identified patch to other code; and

deleting the code buffer.

9. A method of handling links between fragments of code in a self-modifying multi-threaded computer system, the method comprising:

creating patches between compiled pieces of code;

storing information in a patch block about each patch as it is made, each patch block including a from address and a to address;

configuring the patch blocks in a from chain and a to chain;

selecting a code buffer to delete, the code buffer having an address;

generating a hash of the address of the code buffer;

selecting a patch block;

identifying whether there is a patch into the code buffer to be deleted;

if a patch into the code buffer is identified, redirecting the identified patch to other code;

selecting a patch from the from chain;

generating a hash of the selected patch from the from chain;

removing the patch block from the from chain; and

deleting the selected code buffer.

10. A system for handling patches between two pieces of code, the system comprising:

a control device having access to glue code and at least one patch;

a deleter coupled to the control device;

an interpreter coupled to the control device;

a compiler coupled to the control device; and

a hash table coupled to the control device.