Method and apparatus for analyzing software executed in embedded systems

• US 6,161,200 A
• Filed: 03/02/1998
• Issued: 12/12/2000
• Est. Priority Date: 09/11/1995
• Status: Expired due to Term

• 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): LE, DIEU MINH T
• Application Number:
  US09/035,308
• Time in Patent Office: 1,016 Days
• Field of Search: 714/38, 714/39, 714/45, 395/701, 395/704, 717/1, 717/4
• 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 method of analyzing software being executed in a target system, comprising:

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

storing in a symbol database instrumentation data associated with each executable tag statement inserted into the software;

retrieving tags during execution of the software from the at least one predetermined location; and

determining, during execution of the software, the software locations that have been executed by using the tag values of the retrieved tags as keys for retrieving from the symbol database the instrumentation data associated with each of the retrieved tags.

2. The method of claim 1 wherein retrieving tags during execution of the software comprises:

allowing the target system to execute the software;

monitoring the at least one predetermined location while the target system executes the software; and

capturing tags from the at least one predetermined location as the monitored target system executes tag statements.

3. The method of claim 1, further comprising:

maintaining, while the software executes, an output data set that lists each of the software locations executed and a number of respective times that the software locations have been executed.

4. The method of claim 1 wherein at least one of the executable tag statements is inserted in the software at a software location that will cause the tag statement to be executed along with a memory allocation statement, and wherein the method further comprises:

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

storing in the symbol database the data value and instrumentation data associated with the executable data tag statement.

5. The method of claim 4, further comprising:

detecting when the at least another predetermined location in the address space of the target system is being addressed;

capturing a data tag directed to the at least another predetermined location when addressing of the at least another predetermined location is detected; and

determining a memory allocation resulting from the memory allocation statement by retrieving from the symbol database the instrumentation data associated with the data tag by using the data value as a reference key for looking up the instrumentation data.

6. The method of claim 1, further comprising:

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

determining which function call statements of the software are linked to other function call statements of the software based on the order in which the respective tags are retrieved from the at least one predetermined location.

7. The method of claim 6, further comprising compiling a statistical record of the frequency at which specific function call statements are called by specific calling functions.

8. The method of claim 1, further comprising:

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

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

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

9. The method of claim 1 wherein the respective tags may be either control tags or data tags, the control tags including a field having a tag value corresponding to the software location of a control tag statement generating the control tag, the 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 the data tag is associated.

10. The method of claim 1 wherein the instrumentation data includes the tag values.

11. A system for analyzing a computer program executed in a target system, comprising:

a tagging instrumenter that inserts a plurality of executable tag statements having tag values into the computer program at tagging locations and records instrumentation data related to the tagging locations;

a symbol database that contains the tag values associated with the plurality of executable tag statements and the instrumentation data; and

a program memory containing instructions of the computer program causing the target system to write at least one tag to at least one predetermined location in an address space of the target system during the execution of the computer program in the target system, the at least one tag containing a respective tag value corresponding to a tagging location in the computer program.

12. The system of claim 11, further comprising:

a probe that captures tags from the at least one predetermined location while the target system executes the computer program; and

a tagging analyzer that receives the tags from the probe and uses the received tag values as reference keys for retrieving the instrumentation data associated with the executed tagging statements from the symbol database.

13. The system of claim 12 wherein the tagging analyzer determines computer program locations that have been executed based upon the instrumentation data retrieved from the symbol database.

14. The system of claim 12, further comprising:

a time tag generator connected to the probe, the time tag generator recording respective times when the probe captures the tags from the target system,

wherein the tagging analyzer determines the time required for executing the software between first and second locations based on the difference between first and second times recorded when the probe captures first and second tags.

15. The system of claim 12 wherein at least some of the tags have a tag type field corresponding to an analysis function for which the tag is used, and wherein the tag analyzer processes the tags differently according to their respective analysis functions based on respective values in the tag type field regardless of the location in the address space to which the tag is written.

16. The system of claim 12 wherein the tagging instrumenter inserts at least one of the tag statements in the software at a tagging location that will cause the tag statement to be executed along with a memory allocation statement, and wherein the tagging instrumenter inserts an executable data tag statement in the software at a tagging location that will be executed along with the memory allocation statement, the data tag statement, when executed, causing the target system to write a data tag to at least another predetermined location in the address space of the target system, the data tag containing a data value indicative of the memory being allocated by the memory allocation statement, and wherein the tagging analyzer further comprises:

a memory allocation analyzer that determines the memory allocation resulting from the memory allocation statement based on the data value of the data tag captured by the probe and maintains a running account of the memory allocated by the memory allocation statements based on the data values of respective data tags captured by the probe.

17. The system of claim 16 wherein the memory allocation analyzer generates a graph in essentially real time of the amount of memory allocated based on the running account.

18. The system of claim 12 wherein the tagging instrumenter inserts tag statements in the software at tagging locations causing respective tag statements to be executed along with a plurality of function call statements, and wherein the tagging analyzer includes a call pair analyzer that determines which functions of the software are linked to other functions of the software based on the order in which the probe captures the tags.

19. The system of claim 18 wherein the call pair analyzer compiles a statistical record of a relative frequency at which specific called functions are called by specific calling functions.

20. The system of claim 11 wherein the tagging instrumenter inserts the tagging statements into the computer program when source code for the computer program is compiled.

21. The system of claim 11 wherein the tagging instrumenter inserts the tagging statements into the computer program before source code for the computer program is compiled.

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

a probe communicating with the target system while the target system executes the software, the probe capturing tags from the target system when executable respective tag statements are executed;

a processor connected to the probe, the processor determining software locations that have been executed based on the respective tag values of the captured tags while the target system executes the software; and

a symbol database communicating software location data to the processor, the symbol database receiving from the processor the respective tag values of the captured tags, the processor using the respective tag values as reference keys for retrieving corresponding software location data.

23. The system of claim 22 wherein the processor further determines a duration that the software executes a function in the software for each of a plurality of tasks calling the function based upon analysis of received tag values and software location data.

24. The system of claim 22 wherein the processor utilizes the software location data from the symbol database to detect when the software is performing a function in one of a plurality of tasks calling the function and alters its performance in response thereto.

25. The system of claim 24 wherein the processor traces the execution of the software only when the processor determines from the software location data retrieved from the symbol database that the software is performing the function in the one of a plurality of tasks calling the function.

26. The system of claim 24 wherein the processor uses the software location data from the symbol database to identify a memory characteristic being allocated in the target system when the processor detects that the software is executing the function in the one of a plurality of tasks calling the function.