Recompiling with Generic to Specific Replacement

• US 20120233601A1
• Filed: 05/01/2012
• Published: 09/13/2012
• Est. Priority Date: 05/01/2012
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Concurix Corporation
• Inventors: Gounares, Alexander G., Garrett, Charles D.
• Granted Patent: US 8,726,255 B2
• Time in Patent Office: Days
• US Class Current: 717/143
• CPC Class Codes: G06F 8/443 Optimisation
• CPC Class Codes: G06F 8/53 Decompilation; Disassembly

Abstract

Executable code may be recompiled so that generic portions of code may be replaced with specific portions of code. The recompilation may customize executable code for a specific use or configuration, making the code lightweight and executing faster. The replacement mechanism may replace variable names with fixed values, replace conditional branches with only those branches which are known to be executed, and may eliminate executable code portions that are not executed. The replacement mechanism may comprise identifying known values defined in the executable code for variables, and replacing those variables with the constant value. Once the constants are substituted, the code may be analyzed to identify branches that may be evaluated using the constant values. Those branches may be reformed using the constant value and the rest of the conditional code that may not be accessed may be removed.

Claims

1. A method comprising:

receiving a set of executable code;

decompiling said set of executable code;

determining a first constant value for a first variable in said executable code;

for each occurrence of said first variable, replacing said first variable with said first constant value to create a first modified set of executable code; and

recompiling said first modified set of executable code to create a second set of executable code.

2. The method of claim 1 further receiving a semantic definition of said executable code, said semantic definition being used to identify at least one occurrence of said first variable.

3. The method of claim 2, said semantic definition being one of a group composed of:

debugger symbols;

source code; and

intermediate code.

4. The method of claim 1 further comprising:

analyzing said first modified set of executable code to identify conditions that are satisfied when said first variable is defined at said first constant value;

for each of said conditions, removing said conditions from said first modified set of executable code.

5. The method of claim 4 further comprising:

identifying an orphan code in a first condition, said first condition being satisfied when said first variable is defined at said first constant value; and

removing said orphan code from said first modified set of executable code.

6. The method of claim 5, said executable code being application code.

7. The method of claim 6, said decompiling being performed in an executable environment, said executable environment being separate from an operating system.

8. The method of claim 6, said decompiling being performed in an operating system.

9. The method of claim 8, said second set of modified executable code comprising operating system code.

10. A system comprising:

a processor;

a code analyzer operating on said processor, said code analyzer that;

receives a set of executable code and a set of semantic definitions for said executable code;

examines said set of semantic definitions to determine a first constant value for a first variable in said executable code;

for each occurrence of said first variable, replaces said first variable with said first constant value to create a first modified set of executable code; and

recompiles said first modified set of executable code to create a second set of executable code.

11. The system of claim 10, said code analyzer being comprised in an execution environment.

12. The system of claim 10, said code analyzer being executed after receiving a request for executing said executable code.

13. The system of claim 10, said executable code comprising application executable code.

14. The system of claim 10, said executable code comprising operating system executable code.

15. The system of claim 14, said executable code further comprising application executable code.

16. The system of claim 10, said code analyzer being comprised in an operating system.

17. The system of claim 16, said second set of executable code being executed on a second system having a second processor.

18. A method comprising:

receiving a set of executable code, said executable code comprising application code;

decompiling said set of executable code;

identifying links from said application code to operating system code and incorporating said operating system code into said set of executable code;

determining a first constant value for a first variable in said executable code;

for each occurrence of said first variable, replacing said first variable with said first constant value to create a first modified set of executable code; and

recompiling said first modified set of executable code to create a second set of executable code.

19. The method of claim 18 further comprising:

downloading said second set of executable code to a client device.

20. The method of claim 19, said second set of executable code being the complete set of executable code executing on said client device.