Apparatus and methods for placing a managed heap

• US 20050246402A1
• Filed: 05/01/2004
• Published: 11/03/2005
• Est. Priority Date: 05/01/2004
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Wu, Gansha, Lueh, Guei-Yuan
• Granted Patent: US 7,240,176 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 12/0223 User address space allocation, e.g. contiguous or non contiguous base addressing
• CPC Class Codes: Y10S 707/99953 Recoverability
• CPC Class Codes: Y10S 707/99957 Garbage collection

Abstract

Methods and apparatus are disclosed to intelligently place a managed heap in a memory. An example method disclosed herein identifies a current boundary of a static data region in memory, and sets a lower boundary of the managed heap at an address located a safeguard distance above the identified current boundary of the static data region in memory. Other embodiments may be described and claimed.

Claims

1. A method of placing a managed heap in a memory comprising:

identifying a current boundary of a static data region in the memory; and

setting a lower boundary of the managed heap at an address located a safeguard distance above the current boundary of the static data region in the memory.

2. A method as defined in claim 1 wherein the lower boundary of the managed heap is set such that a machine accessible instruction within the managed heap addresses the static data region using an immediate value.

3. A method as defined in claim 1 wherein the lower boundary of the managed heap is set such that an immediate value of a pointer to an address in the managed heap is constructed in two instructions.

4. A method as defined in claim 1 wherein the lower boundary of the managed heap is set such that an address within a code segment of the memory is accessed using a direct branch machine accessible instruction in the managed heap.

5. A method as defined in claim 1 wherein identifying the current upper boundary of the static data region comprises determining the current boundary using binary image introspection.

6. A method as defined in claim 1 wherein identifying the current upper boundary of the static data region comprises determining the current upper boundary using a system call.

7. A method as defined in claim 1 wherein the safeguard distance is larger than a maximum growth amount of the static data region.

8. A method as defined in claim 1 wherein setting a lower boundary of the managed heap comprises summing a memory address of the current boundary of the static data region, and a maximum growth amount of the static data region.

9. A method as defined in claim 1 wherein setting the lower boundary of the managed heap is performed during a runtime initialization phase.

10. A method as defined in claim 1 further comprising generating a direct branch from Just-in Time code located in the managed heap to virtual machine code located in a static code segment.

11. A method as defined in claim 1 further comprising compressing a managed pointer to an address in the managed heap.

12. A method as defined in claim 11 wherein compressing the managed pointer comprises:

decomposing the managed pointer into a predetermined base value and an offset value; and

storing the offset value.

13. A method as defined in claim 12 wherein storing the offset value comprises storing all but the last two bits of the offset value.

14. A method as defined in claim 12 wherein the managed pointer points from a first address in the managed heap to a second address in the managed heap.

15. A method as defined in claim 12 wherein the managed pointer points from an address in the managed heap to an address in the static data region.

16. A method as defined in claim 12 wherein a predetermined number of bits of the base are combined with a predetermined number of bits of the offset to address the managed heap.

17. A method as define in claim 1 further comprising constructing a managed pointer to an address in the managed heap.

18. A method as defined in claim 17 wherein constructing the managed pointer comprises constructing the managed pointer from a predetermined base and an offset value.

19. A method as defined in claim 18 further comprising adding two bits to the offset value.

20. An apparatus to place a managed heap in a memory comprising:

a boundary locator to identify a current boundary of a static data region in the memory; and

,

a heap placement engine to set a lower boundary of the managed heap at an address located a safeguard distance above the current boundary.

21. An apparatus as defined in claim 20 wherein the safeguard distance is larger than a maximum growth amount of the static data region.

22. A compiler system comprising:

a dynamic random access memory;

a boundary locator to identify a current boundary of a static data region in the dynamic random access memory; and

,

a heap placement engine to set a lower boundary of a managed heap at an address in the dynamic random access memory located a safeguard distance above the current boundary.

23. A system as defined in 22 wherein the safeguard distance is larger than a maximum growth amount of the static data region.

24. A machine accessible medium containing instructions which, when executed, cause a machine to:

identify a current boundary of a static data region in a memory; and

set a lower boundary of the managed heap at an address located a safeguard distance above the current boundary of a static data in memory.

25. A machine accessible medium as defined in claim 24 wherein the safeguard distance is larger than a maximum growth amount of the static data region.

26. A method of constructing a pointer to an address in a managed heap comprising:

loading an offset portion of the address;

appending a predetermined value to the offset to generate an intermediate address; and

combining the intermediate address with a predetermined base address of a managed heap.

27. A method as defined in claim 26 wherein the predetermined base comprises sixteen bits of the address.

28. A method as defined in claim 26 wherein combining the intermediate address with the predetermined base address comprises loading the base into a first predetermined portion of a register.

29. A method as defined in claim 26 wherein loading the offset portion comprises loading the offset portion into a second predetermined portion of the register.

30. A method as defined in claim 26 wherein appending the predetermined value comprises shifting the offset.

31. A method as defined in claim 26 wherein the predetermined value is dependent on the memory allocation structure.