# java-callgraph **Repository Path**: MTV168168/java-callgraph ## Basic Information - **Project Name**: java-callgraph - **Description**: No description available - **Primary Language**: Unknown - **License**: Not specified - **Default Branch**: master - **Homepage**: None - **GVP Project**: No ## Statistics - **Stars**: 0 - **Forks**: 1 - **Created**: 2022-04-08 - **Last Updated**: 2022-04-08 ## Categories & Tags **Categories**: Uncategorized **Tags**: None ## README java-callgraph: Java Call Graph Utilities ========================================= A suite of programs for generating static and dynamic call graphs in Java. * javacg-static: Reads classes from a jar file, walks down the method bodies and prints a table of caller-caller relationships. * javacg-dynamic: Runs as a [Java agent](http://download.oracle.com/javase/6/docs/api/index.html?java/lang/instrument/package-summary.html) and instruments the methods of a user-defined set of classes in order to track their invocations. At JVM exit, prints a table of caller-callee relationships, along with a number of calls #### Compile The java-callgraph package is build with maven. Install maven and do: ``` mvn install ``` This will produce a `target` directory with the following three jars: - javacg-0.1-SNAPSHOT.jar: This is the standard maven packaged jar with static and dynamic call graph generator classes - `javacg-0.1-SNAPSHOT-static.jar`: This is an executable jar which includes the static call graph generator - `javacg-0.1-SNAPSHOT-dycg-agent.jar`: This is an executable jar which includes the dynamic call graph generator #### Run Instructions for running the callgraph generators ##### Static `javacg-static` accepts as arguments the jars to analyze. ``` java -jar javacg-0.1-SNAPSHOT-static.jar lib1.jar lib2.jar... ``` `javacg-static` produces combined output in the following format: ###### For methods ``` M:class1:(arg_types) (typeofcall)class2:(arg_types) ``` The line means that `method1` of `class1` called `method2` of `class2`. The type of call can have one of the following values (refer to the [JVM specification](http://java.sun.com/docs/books/jvms/second_edition/html/Instructions2.doc6.html) for the meaning of the calls): * `M` for `invokevirtual` calls * `I` for `invokeinterface` calls * `O` for `invokespecial` calls * `S` for `invokestatic` calls * `D` for `invokedynamic` calls For `invokedynamic` calls, it is not possible to infer the argument types. ###### For classes ``` C:class1 class2 ``` This means that some method(s) in `class1` called some method(s) in `class2`. ##### Dynamic `javacg-dynamic` uses [javassist](http://www.csg.is.titech.ac.jp/~chiba/javassist/) to insert probes at method entry and exit points. To be able to analyze a class `javassist` must resolve all dependent classes at instrumentation time. To do so, it reads classes from the JVM's boot classloader. By default, the JVM sets the boot classpath to use Java's default classpath implementation (`rt.jar` on Win/Linux, `classes.jar` on the Mac). The boot classpath can be extended using the `-Xbootclasspath` option, which works the same as the traditional `-classpath` option. It is advisable for `javacg-dynamic` to work as expected, to set the boot classpath to the same, or an appropriate subset, entries as the normal application classpath. Moreover, since instrumenting all methods will produce huge callgraphs which are not necessarily helpful (e.g. it will include Java's default classpath entries), `javacg-dynamic` includes support for restricting the set of classes to be instrumented through include and exclude statements. The options are appended to the `-javaagent` argument and has the following format ``` -javaagent:javacg-dycg-agent.jar="incl=mylib.*,mylib2.*,java.nio.*;excl=java.nio.charset.*" ``` The example above will instrument all classes under the the `mylib`, `mylib2` and `java.nio` namespaces, except those that fall under the `java.nio.charset` namespace. ``` java -Xbootclasspath:/System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Classes/classes.jar:mylib.jar -javaagent:javacg-0.1-SNAPSHOT-dycg-agent.jar="incl=mylib.*;" -classpath mylib.jar mylib.Mainclass ``` `javacg-dynamic` produces two kinds of output. On the standard output, it writes method call pairs as shown below: ``` class1:method1 class2:method2 numcalls ``` It also produces a file named `calltrace.txt` in which it writes the entry and exit timestamps for methods, thereby turning `javacg-dynamic` into a poor man's profiler. The format is the following: ``` <>[stack_depth][thread_id]fqdn.class:method=timestamp_nanos ``` The output line starts with a `<` or `>` depending on whether it is a method entry or exit. It then writes the stack depth, thread id and the class and method name, followed by a timestamp. The provided `process_trace.rb` script processes the callgraph output to generate total time per method information. #### Examples The following examples instrument the [Dacapo benchmark suite](http://dacapobench.org/) to produce dynamic call graphs. The Dacapo benchmarks come in a single big jar archive that contains all dependency libraries. To build the boot class path required for the javacg-dyn program, extract the `dacapo.jar` to a directory: all the required libraries can be found in the `jar` directory. Running the batik Dacapo benchmark: ``` java -Xbootclasspath:/System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Classes/classes.jar:jar/batik-all.jar:jar/xml-apis-ext.jar -javaagent:target/javacg-0.1-SNAPSHOT-dycg-agent.jar="incl=org.apache.batik.*,org.w3c.*;" -jar dacapo-9.12-bach.jar batik -s small |tail -n 10 ```
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``` Running the lucene Dacapo benchmark: ``` java -Xbootclasspath:/System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Classes/classes.jar:jar/lucene-core-2.4.jar:jar/luindex.jar -javaagent:target/javacg-0.1-SNAPSHOT-dycg-agent.jar="incl=org.apache.lucene.*;" -jar dacapo-9.12-bach.jar luindex -s small |tail -n 10 ```

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``` #### Known Restrictions * The static call graph generator does not account for methods invoked via reflection. * The dynamic call graph generator will not work reliably (or at all) for multithreaded programs * The dynamic call graph generator does not handle exceptions very well, so some methods might appear as having never returned #### Author Georgios Gousios #### License [2-clause BSD](http://www.opensource.org/licenses/bsd-license.php)