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 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.
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
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 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
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.
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:
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 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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