Using IBM Wala’s Slicer for CSCI578 HW3

1. Using IBM Wala’s Slicer for CSCI578 HW3 By Joshua Garcia

2. Some Requirements • Eclipse IDE • SVN or GitPlugin for Eclipse (e.g. Subclipse at http://subclipse.tigris.org/)

3. Getting the IBM Wala code • Check out all com.ibm.wala* projects form the trunk of the repository EXCEPT for com.ibm.wala.core.tests • Import com.ibm.wala.core.tests from the zip file we provide • Reference • A more general guide to starting with Wala: http://wala.sourceforge.net/wiki/index.php/UserGuide:Getting_Started

4. Possible Building Problems • Some of the projects will have errors. I have errors in the following Wala projects: • com.ibm.wala.cast.js.rhino.test • com.ibm.wala.cast.js.test • com.ibm.wala.ide.jsdt • com.ibm.wala.ide.tests • However, you won’t be using all the code so it shouldn’t be a problem • However, you should set your JDK compiler compliance level to 1.6 • Click Window -> Preferences • Java -> Compiler • Set Compiler compliance level to 1.6

5. Configuring Properties Files • Go to this page: http://wala.sourceforge.net/wiki/index.php/UserGuide:Getting_Started • Follow the section called “Configuring WALA properties” • Wait there’s more and it’s IMPORTANT – You need to set some properties in dat/wala.examples.properties as well • Just copy the wala.example.properties.sample file and rename it

6. A Little About Slicing Before We Continue • Given a statement and a subset of its variables, you can perform forward or backward slicing • A slice is a set of statements that affect or are affected by the selected statement • Forward slicing gives you the statements affected by your selected statement • Backward slicing gives you the statements that affect the given statement

7. More on slicing, If You Are Interested • http://www.grammatech.com/research/papers/slicing/slicingWhitepaper.html • http://en.wikipedia.org/wiki/Program_slicing

8. Time To Slice Some Programs • You should be able to run our customized PDFSliceMod drivers • There are three launcher configuration you can modify and run as needed (one for each DEB application): • PDFSliceMod KLAX • PDFSliceModspecjms from stmts file • PDFSliceModstoxx • Simple way to get to these launcher configurations • Click Run -> Run Configurations • Under Java Application select the appropriate launcher configuration

9. Customizing the launcher configuration • The launcher configuration takes a few arguments • You can see these arguments from the Arguments tab of the launcher configuration • For example, for PDFSliceMod KLAX, here are the arguments • -appJar ${workspace_loc}/com.ibm.wala.core.tests/apps/c2fw-original.jar -sliceCritFiles "${workspace_loc}/com.ibm.wala.core.tests/c2fw-mda-task0-search-deps-stmts.txt" -dd "no_base_no_heap" -cd "none" -dir "backwards" -pkgIncludes "Lc2/apps/klax" • The arguments and what they do • appJar, the jar of the DEB application (no need to change it) • srcCaller, the method you will create the slice from • sliceCritFiles, file name of the file containing the input statements to the slicer • dir, “forward” or “backward” slice • pkgIncludes, which packages to analyze and show for output • For the remaining options take a look at http://wala.sourceforge.net/wiki/index.php/UserGuide:Slicer • You may not need to change dd or cd, unless you think it will give you more accurate results • Changing dd or cd can make your program running for a very long time • A slicer on our DEB applications can take minutes to run

10. Understanding the console output • The slicer’s analysis starts from entry points in your program, which are set to all the methods of your selected class • One statement can be broken up into multiple IR statements. For example line 70 of KLAX’s ChuteArtist class is made up of these statements (and some null statements): • 70 18 = invokevirtual < Application, Lc2/fw/Notification, getParameter(Ljava/lang/String;)Ljava/lang/Object; > 2,16 @22 exception:17 • 70 19 = checkcast <Application,Ljava/lang/Integer>18 <Application,Ljava/lang/Integer> • 70 21 = invokevirtual < Application, Ljava/lang/Integer, intValue()I > 19 @28 exception:20

11. More on console output • You get the statements of the slice and corresponding line numbers (if applicable): Printing slice with node number and line number: SLICE: 1, -1 NORMAL_RET_CALLER:Node: < Application, Lc2/apps/klax/comp/ChuteArtist, handle(Lc2/fw/Notification;)V > Context: Everywhere[1]5 = invokevirtual < Application, Lc2/fw/Notification, name()Ljava/lang/String; > 2 @1 exception:4 2, 66 NORMAL handle:8 = invokevirtual < Application, Ljava/lang/String, equals(Ljava/lang/Object;)Z > 5,6 @8 exception:7 Node: < Application, Lc2/apps/klax/comp/ChuteArtist, handle(Lc2/fw/Notification;)V > Context: Everywhere 3, -1 PARAM_CALLER:Node: < Application, Lc2/apps/klax/comp/ChuteArtist, handle(Lc2/fw/Notification;)V > Context: Everywhere[5]8 = invokevirtual < Application, Ljava/lang/String, equals(Ljava/lang/Object;)Z > 5,6 @8 exception:7 v5 4, 74 NORMAL handle:12 = invokevirtual < Application, Ljava/lang/String, equals(Ljava/lang/Object;)Z > 5,10 @56 exception:11 Node: < Application, Lc2/apps/klax/comp/ChuteArtist, handle(Lc2/fw/Notification;)V > Context: Everywhere 5, -1 PARAM_CALLER:Node: < Application, Lc2/apps/klax/comp/ChuteArtist, handle(Lc2/fw/Notification;)V > Context: Everywhere[29]12 = invokevirtual < Application, Ljava/lang/String, equals(Ljava/lang/Object;)Z > 5,10 @56 exception:11 v5 Node 2 corresponds to line 66 of ChuteArtist Some IR statements have no corresponding line number Node Numbers

12. How to read your slice Printing slice with selected statements only: Lorg/spec/jms/eventhandler/sp/SP_CallForOffersEH:306 NORMAL handleMessage:4 = instanceof 2 <Application,Ljavax/jms/TextMessage> Node: < Application, Log/spec/jms/eventhandler/sp/SP_CallForOffersEH, handleMessage(Ljavax/jms/Message;)V > Context: Everywhere Lorg/spec/jms/eventhandler/sp/SP_CallForOffersEH:306 NORMAL handleMessage:conditional branch(eq) 4,5 Node: < Application, Lorg/spec/jms/eventhandler/sp/SP_CallForOffersEH, handleMessage(Ljavax/jms/Message;)V > Context: Everywhere Lorg/spec/jms/eventhandler/sp/SP_CallForOffersEH:308 NORMAL handleMessage:19 = checkcast <Application,Ljavax/jms/TextMessage>2 <Application,Ljavax/jms/TextMessage> Node: < Application, Lorg/spec/jms/eventhandler/sp/SP_CallForOffersEH, handleMessage(Ljavax/jms/Message;)V > Context: Everywhere Lorg/spec/jms/eventhandler/sp/SP_CallForOffersEH:308 NORMAL handleMessage:21 = invokeinterface < Application, Ljavax/jms/TextMessage, getText()Ljava/lang/String; > 19 @12 exception:20 Node: < Application, Lorg/spec/jms/eventhandler/sp/SP_CallForOffersEH, handleMessage(Ljavax/jms/Message;)V > Context: Everywhere Lorg/spec/jms/eventhandler/sp/SP_CallForOffersEH:308 NORMAL handleMessage:invokevirtual < Application, Lorg/spec/jms/eventhandler/sp/SP_CallForOffersEH, parseMessage(Ljava/lang/String;)V > 1,21 @17 exception:22 Node: < Application, Lorg/spec/jms/eventhandler/sp/SP_CallForOffersEH, handleMessage(Ljavax/jms/Message;)V > Context: Everywhere Class Name Line No.

13. More Stuff You Might Need to Know • How slices map to line numbers: http://wala.sourceforge.net/wiki/index.php/UserGuide:MappingToSourceCode#From_Slices_to_source_line_numbers • Understanding the IR: http://wala.sourceforge.net/wiki/index.php/UserGuide:IR

14. Eclipse’s Reference-finding Feature • Right click on method, variable, class, etc. • Select References -> Project, Hierarchy, Workspace, or Working Set • You get list of references to your selection • Or simply highlight the method, variable, class etc. • Press Ctrl+Shift+G