Method and apparatus for analyzing software executed in embedded systems

• US 5,748,878 A
• Filed: 09/11/1995
• Issued: 05/05/1998
• Est. Priority Date: 09/11/1995
• Status: Expired due to Fees

• Current Assignee: Freescale Semiconductor, Inc. (NXP Semiconductors NV)
• Original Assignee: Applied Microsystems Corporation
• Inventors: Rees, Andrew John, Krystad, Peter D., O'Brien, Stephen Caine
• Primary Examiner(s): Beausoliel, Jr., Robert W.
• Assistant Examiner(s): LE, DIEU MINH T
• Application Number:
  US08/526,709
• Time in Patent Office: 967 Days
• Field of Search: 395/183.14, 395/183.15, 395/183.21, 395/500, 395/704, 395/708, 364/267, 364/267.91
• US Class Current: 714/38.13
• CPC Class Codes: G06F 11/25 Testing of logic operation, e.g. by logic analysers
• CPC Class Codes: G06F 11/3466 Performance evaluation by tracing or monitoring
• CPC Class Codes: G06F 11/3624 by performing operations on the source code, e.g. via a compiler
• CPC Class Codes: G06F 11/364 tracing values on a bus

Abstract

A software analysis system for capturing tags generated by tag statements in instrumented source code. The software analysis system includes a probe that monitors the address and data bus of the target system. When a tag statement is executed in the target system, a tag is written to a predetermined location in the address space of the target system. The tag contains a tag value that is indicative of the location in the source code of the tag statement generating the tag. By monitoring the predetermined address, the probe is able to capture tags as they are written on the data bus of the target system. By properly instrumenting the source code, the software analysis system is able to perform a variety of analysis functions in essentially real time, including code coverage, function and task execution times, memory allocation, call pairs, and program tracing.

Claims

1. A system for analyzing software being executed in a target system having a data bus and an address bus, said software containing a plurality of executable tag statements which, when executed, cause said target system to write at least one tag to respective predetermined locations in the address space of said target system, said tags containing respective tag values corresponding to the locations in said software of tag statements generating said tags, said system comprising:

a probe connected to the address and data buses of said target system while said target system is executing said software, said probe detecting when said predetermined location in the address space of said target system is being addressed, said probe capturing a tag on the data bus of said target system when said probe detects that said predetermined location has been addressed; and

a processor connected to said probe, said processor processing said tags at a rate sufficient to sustain processing said tags as they are captured while said software is being executed, said processor determining and displaying information about the execution of said software based on said tag values while said software is being executed.

2. The system of claim 1 further comprising:

a time tag generator connected to said probe, said time tag generator recording respective times when said probe captures said tags on the data bus of said target system; and

wherein the processor includes a software performance analyzer determining the time required to execute said software between first and second locations based on the difference between first and second times recorded when first and second tags are captured from said data bus.

3. The system of claim 1 wherein at least some of said tags have a tag type field corresponding to an analysis function for which said tag is used, and wherein said processor includes means for processing said tags differently according to their respective analysis functions based on respective values in said tag type field regardless of the location in the address space to which said tag is written.

4. The system of claim 1, wherein at least one of said tag statements is inserted in said software at a location that will cause said tag statement to be executed along with a memory allocation statement or a library call, and wherein an executable data tag statement is inserted in said software at a location that will be executed along with said memory allocation statement, said data tag statement, when executed, causing said target system to write a data tag to a second predetermined location in the address space of said target system, said data tag containing a data value indicative of the memory being allocated by said memory allocation statement, and wherein said system further includes a memory allocation analyzer connected to said processor, said memory allocation analyzer determining the memory allocation resulting from said memory allocation statement based on the data value of said data tag captured by said probe and maintaining a running account of the memory allocated by said memory allocation statements based on the data values of respective data tags captured by said probe.

5. The system of claim 4 wherein said memory allocation analyzer further includes means for generating a graph in essentially real time of the amount of memory allocated based on said running account.

6. The system of claim 1 wherein said tag statements are inserted in said software at locations causing respective tag statements to be executed along with a plurality of function call statements, and wherein said system further includes a call pair analyzer determining which functions of said software are linked to other functions of said source code based on the order in which said probe captures said tags.

7. The system of claim 6, wherein said call pair analyzer further includes means for compiling a record of the number of times that specific called functions are called by specific calling functions.

8. The system of claim 7, wherein said call pair analyzer further includes means for compiling a statistical record of the frequency at which specific called functions are called by specific calling functions.

9. The system of claim 1 wherein said tag statements are inserted in respective branches of said software so that said tag statements will be executed along with said branches, and wherein said system further includes a code coverage analyzer determining which branches of said software have been executed based on the tag values of said tags captured by said probe.

10. The system of claim 1, wherein said processor comprises a plurality of processor devices performing different respective functions.

11. A system for analyzing software being executed in a target system having a data bus and an address bus, said software containing a plurality of executable tag statements which, when executed, cause said target system to write at least one tag to respective predetermined locations in the address space of said target system, said tags containing respective tag values corresponding to the locations in said software of tag statements generating said tags, said system comprising:

a probe connected to the address and data buses of said target system while said target system is executing said software, said probe detecting when said predetermined location in the address space of said target system is being addressed, said probe capturing a tag on the data bus of said target system when said probe detects that said predetermined location has been addressed;

a processor connected to said probe, said processor determining the software locations that have been executed based on the respective tag values of said captured tags;

a tag filter connected to said processor, said tag filter comprising;

selections means for establishing criteria for processing said tags based on their respective tag values;

comparator means for examining each tag captured by said probe to determine if said tag meets said criteria; and

filter means for disregarding tags not meeting said criteria so that tags are processed by said processor only if said tags meet said criteria.

12. A system for analyzing software being executed in a target system having a data bus and an address bus, said software containing a plurality of executable tag statements which, when executed cause said target system to write at least one tag to respective predetermined locations in the address space of said target system, said tags containing respective tag values corresponding to the locations in said software of tag statements generating said tags, said system comprising:

a probe tip connected to the address and data buses of said target system while said target system is executing said software, said probe tip detecting when said predetermined location in the address space of said target system is being addressed, said probe tip capturing a tag on the data bus of said target system when said probe tip detects that said predetermined location has been addressed;

a tag preprocessor connected to said probe tip, said tag preprocessor examining said tags and, based upon the contents of said tags, routing said tags to a first output if said tags are being used for a code coverage analysis and routing said tags to a second output if said tags are not being used for a code coverage analysis;

a code coverage data reduction processor and data base connected to the first output of said tag preprocessor;

a tag buffer connected to the second output of said tag preprocessor, said tag buffer storing and then outputting tags received from the second output of said tag preprocessor and

a processor receiving the tags from the tag buffer, said processor determining the source code locations that have been executed based on the respective tag values of said tags.

13. A method of analyzing software being executed in a target system having a data bus and an address bus, said method comprising the steps of:

inserting a plurality of executable tag statements at locations in said software, each of said tag statements, when executed, causing said target system to write a tag to a predetermined location in the address space of said target system, said tags containing respective tag values corresponding the locations in said software of tag statements generating said tags;

allowing said target system to execute said software;

monitoring the address and data buses of said target system while said target system is executing said software;

detecting when said predetermined location in the address space of said target system is being addressed;

capturing a tag on said data bus when addressing of said predetermined location is detected;

determining information about the execution of said software based on said tag values while said software is being executed; and

displaying information about the execution of said software based on said determination while said software is being executed.

14. The method of claim 13 further including the steps of:

recording a first time when a first tag is present on said data bus;

said first tag having a first tag value corresponding to a first location in said software of a first tag statement generating said first tag;

recording a second time when a second tag is present on said data bus;

said second tag having a second tag value corresponding to a second location in said software of a second tag statement generating said second tag; and

based on the difference between said first and second times, determining the time required to execute said software between said first and second locations.

15. The method of claim 13 wherein at least some of said tag statements, when executed, cause said target system to write a tag to a predetermined location in the address space of said target system having a tag type field corresponding to an analysis function of said tag so that different tags may be processed differently according to their respective analysis functions.

16. The method of claim 13, wherein at least one of said tag statements is inserted in said software at a location that will cause said tag statement to be executed along with a memory allocation statement or a library call, and wherein said method further comprises the steps of:

inserting an executable data tag statement in said software at a location that will be executed along with said memory allocation statement, said data tag statement, when executed, causing said target system to write a data tag to a second predetermined location in the address space of said target system, said data tag containing a data value indicative of a characteristic of the memory being allocated by said memory allocation statement;

detecting when said second predetermined location in the address space of said target system is being addressed;

capturing a data tag on said data bus when addressing of said second predetermined location is detected; and

determining the memory allocation resulting from said memory allocation statement based on the data value of said captured data tag.

17. The method of claim 16 further including the step of placing data tag statements in software locations so that a data tag statement will be executed with the execution of each memory allocation statement, and wherein said method further includes the step of maintaining a running account of the memory allocated by said memory allocation statements based on the data values of respective captured data tags.

18. The method of claim 17 further including the step of generating a graph in essentially real time of the amount of memory allocated based on said running account.

19. The method of claim 16, wherein the data value contained in said data tag provides an indication of the size of a block of memory being allocated.

20. The method of claim 16, wherein the data value contained in said data tag provides an indication of the type of said memory allocation statement.

21. The method of claim 16, wherein the data value contained in said data tag provides an indication of an erroneous memory allocation.

22. The method of claim 16, wherein the data value contained in said data tag provides an indication of the size of a block of memory being allocated.

23. The method of claim 16, wherein the data value contained in said data tag provides an indication of the address of the memory being allocated by said memory allocation statement in said software.

24. The method of claim 13, further including the steps of:

inserting tag statements in said software at locations causing respective tag statements to be executed along with a plurality of function call statements; and

based on the order in which said tags are captured when addressing of said predetermined location is detected, determining which functions of said software are linked to other functions of said software.

25. The method of claim 24, further including the step of compiling a record of the number of times that specific called functions are called by specific calling functions.

26. The method of claim 24, further including the step of compiling a statistical record of the frequency at which specific called functions are called by specific calling functions.

27. The method of claim 13, further including the steps of:

inserting tag statements in respective branches of said software so that said tag statements will be executed along with said branches; and

based on the tag values of said tags captured when addressing of said predetermined location is detected, determining which branches of said software have been executed.

28. The method of claim 13 wherein said tags may be either control tags or data tags, said control tags including a field having a tag value corresponding to the software location of a control tag statement generating said control tag, said data tags being associated with a respective control tag and having a data field that provides information about an event identified by the control tag with which said data tag is associated.

29. The method of claim 13 wherein said method further includes the step of determining an execution context from a record of the source code locations that have been executed by said target system, the execution context being determined while said software is being executed.

30. The method of claim 29, further including the step of using said execution context determination to control the progress of said analysis, while said software is being executed.

31. The method of claim 29 wherein said tags are used to produce a task performance analysis.

32. The method of claim 29 wherein said step of determining an execution context comprises determining a task context from a record of the source code locations that have been executed by said target system, the execution context being determined while said software is being executed.

33. The method of claim 29 wherein said step of determining an execution context comprises determining a function nesting hierarchy from a record of the source code locations that have been executed by said target system, the nesting hierarchy being determined while said software is being executed.

34. The method of claim 13 wherein said tag statements are inserted in the source code of said software, and wherein said method further includes the steps of compiling said source code and inserted tag statements to obtain object code, and executing said object code in said target system.

35. A method of analyzing software being executed in a target system having a data bus and an address bus, said method comprising the steps of:

inserting a plurality of executable tag statements at locations in said software, each of said tag statements, when executed, causing said target system to write a tag to a predetermined location in the address space of said target system, said tags containing respective tag values corresponding the locations in said software of tag statements generating said tags;

allowing said target system to execute said software;

monitoring the address and data buses of said target system while said target system is executing said software;

detecting when said predetermined location in the address space of said target system is being addressed;

capturing a tag on said data bus when addressing of said predetermined location is detected;

establishing criteria for processing said tags based on their respective tag values;

examining each captured tag to determine if said tag meets said criteria; and

subsequently processing and displaying respective software locations that have been executed based on said tags only if said tags meet said criteria, thereby filtering said tags after said tags have been captured.

36. A system for determining and displaying the context of software being executed in a target system having a data bus and an address bus, said software containing a plurality of executable tag statements which, when executed, cause said target system to write a plurality of tags to at least one location in the address space of said target system, said tags containing respective tag values corresponding to the locations in said software of respective tag statements generating said tags, said system comprising:

a probe connected to the address and data buses of said target system while said target system is executing said software, said probe capturing tags on the data bus of said target system when said tag statements generating said tags are executed; and

a processor connected to said probe, said processor determining the software locations that have been executed based on the respective tag values of said captured tags while said software is being executed by said target system, said processor determining and displaying the context of said software currently being executed by said target system.

37. The system of claim 36 wherein said processor further determines a duration that said software is executing a function for each of a plurality of tasks calling said function.

38. The system of claim 36 wherein said processor further detects when said software is performing a function in one of a plurality of tasks calling said function and alters its performance in response thereto.

39. The system of claim 38 wherein said processor traces the execution of said software only when said processor detects that said software is performing the function in the one of a plurality of tasks calling said function.

40. The system of claim 38 wherein said processor determines a characteristic of the memory being allocated in said target system only when said processor detects that said software is executing the function in the one of a plurality of tasks calling said function.

41. A system for determining and displaying the coverage of software being executed in a target system having a data bus and an address bus, said software containing a plurality of executable tag statements which, when executed, cause said target system to write a plurality of tags to at least one location in the address space of said target system, said tags containing respective tag values corresponding to the locations in said software of respective tag statements generating said tags, said system comprising:

a probe connected to the address and data buses of said target system while said target system is executing said software, said probe capturing tags on the data bus of said target system when said tag statements generating said tags are executed; and

a processor connected to said probe, said processor determining the software locations that have been executed based on the respective tag values of said captured tags while said software is being executed by said target system, said processor maintaining a database indicative of the execution of portions of said software while said software is being executed, said database listing each of said software portions and the numbers of respective times that said software portions have been executed.

42. A method of determining and displaying the context of software being executed in a target system having a data bus and an address bus, comprising the steps of:

inserting a plurality of executable tag statements at locations in said software which, when executed, cause said target system to write a plurality of tags to at least one location in the address space of said target system, said tags containing respective tag values corresponding to the locations in said software of respective tag statements generating said tags;

allowing said target system to execute said software;

monitoring the data bus of said target system while said target system is executing said software;

capturing tags on said data bus when said tag statements generating said tags are executed;

determining the software locations that have been executed based on the respective tag values of said captured tags while said software is being executed by said target system; and

determining and displaying the context of said software currently being executed by said target system.

43. The method of claim 42 wherein said method further comprises the step of determining the duration that said software is performing a function for each of a plurality of tasks calling said function.

44. The method of claim 42 wherein said method further comprises the steps of detecting when said software is performing a function in one of a plurality of tasks calling said function and, in response thereto, tracing the execution of said software.

45. The method of claim 42 wherein said method further comprises the steps of detecting when said software is performing a function in one of a plurality of tasks calling said function and, in response thereto, determining a characteristic of the memory being allocated in said target system.

46. A method of determining and displaying the coverage of software being executed in a target system having a data bus and an address bus, comprising:

inserting a plurality of executable tag statements at locations in said software which, when executed, cause said target system to write a plurality of tags to at least one location in the address space of said target system, said tags containing respective tag values corresponding to the locations in said software of respective tag statements generating said tags;

allowing said target system to execute said software;

monitoring the data bus of said target system while said target system is executing said software;

capturing tags on said data bus when said tag statements generating said tags are executed;

determining the software locations that have been executed based on the respective tag values of said captured tags while said software is being executed by said target system; and

maintaining a database indicative of the execution of portions of said software while said software is being executed, said database listing each of said software portions and the numbers of respective times that said software portions have been executed.