Detecting data races in multithreaded computer programs

1. A machine-implemented method of processing program code, comprising:

storing in a thread-local variable a value of a variable shared by multiple threads for executing the program code;

detecting a data race condition based on a comparison of values of the shared variable and the thread-local variable; and

reporting detection of the data race condition.

2. The method of claim 1 , wherein the shared variable value is stored to the thread-local variable during execution of at least a given one of the threads sharing the shared variable.

3. The method of claim 2 , wherein the data race condition is detected during execution of the given thread.

4. The method of claim 3 , wherein the detection of the data race condition is reported during execution of the given thread.

5. The method of claim 1 , further comprising comparing the values of the shared variable and the thread-local variable after the shared variable value is stored in the thread-local variable, and subsequently loading the shared variable value.

6. The method of claim 1 , wherein the data race condition is detected based on a determination that the values of the shared variable and the thread-local variable are different.

7. The method of claim 1 , wherein the reporting comprises reporting a detection of the data race condition in response to a determination that the values of the shared variable and the thread-local variable are different.

8. A machine-readable medium storing machine-readable instructions for causing a machine to:

store in a thread-local variable a value of a variable shared by multiple threads for executing the program code;

detect a data race condition based on a comparison of values of the shared variable and the thread-local variable; and

report detection of the data race condition.

9. The machine-readable medium of claim 8 , wherein the machine-readable instructions cause a machine to store the shared variable value to the thread-local variable during execution of at least a given one of the threads sharing the shared variable.

10. The machine-readable medium of claim 9 , wherein the machine-readable instructions cause a machine to detect the data race condition during execution of the given thread.

11. The machine-readable medium of claim 10 , wherein the machine-readable instructions cause a machine to report the detection of the data race condition during execution of the given thread.

12. The machine-readable medium of claim 8 , wherein the machine-readable instructions cause a machine to compare the values of the shared variable and the thread-local variable after the shared variable value is stored in the thread-local variable, and to subsequently load the shared variable value.

13. The machine-readable medium of claim 8 , wherein the machine-readable instructions cause a machine to detect the data race condition based on a determination that the values of the shared variable and the thread-local variable are different.

14. The machine-readable medium of claim 8 , wherein the machine-readable instructions cause a machine to report a detection of the data race condition in response to a determination that the values of the shared variable and the thread-local variable are different.

15. A machine-implemented method of processing program code, comprising:

generating a machine-readable instruction to store in a thread-local variable a value of a variable shared by multiple threads for executing the program code;

generating a machine-readable instruction to detect a data race condition based on a comparison of values of the shared variable and the thread-local variable; and

storing the machine-readable instructions in a machine-readable medium.

16. The method of claim 15 , further comprising generating a machine-readable instruction to report detection of the data race condition.

17. The method of claim 15 , further comprising identifying the shared variable.

18. The method of claim 15 , further comprising identifying an access to the shared variable to test for occurrence of a data race condition.

19. The method of claim 15 , further comprising determining whether an instruction in the program code stores a value to the shared variable.

20. The method of claim 19 , wherein the machine-readable instruction to store the shared variable value to the thread-local variable is generated in response to a positive determination that the program code instruction stores a value to the shared variable.

21. The method of claim 19 , wherein the machine-readable instruction to detect the data race condition is generated in response to a negative determination that the program code instruction stores a value to the shared variable.

22. A machine-readable medium storing machine-readable instructions for causing a machine to:

generate a machine-readable instruction to store in a thread-local variable a value of a variable shared by multiple threads for executing the program code;

generate a machine-readable instruction to detect a data race condition based on a comparison of values of the shared variable and the thread-local variable; and

store the machine-readable instructions in a machine-readable medium.

23. The machine-readable medium of claim 22 , wherein the machine-readable instructions cause a machine to generate a machine-readable instruction to report detection of the data race condition.

24. The machine-readable medium of claim 22 , wherein the machine-readable instructions cause a machine to identify the shared variable.

25. The machine-readable medium of claim 22 , wherein the machine-readable instructions cause a machine to identify an access to the shared variable to test for occurrence of a data race condition.

26. The machine-readable medium of claim 22 , wherein the machine-readable instructions cause a machine to determine whether an instruction in the program code stores a value to the shared variable.